Functional and structural regeneration in the axolotl heart ( Ambystoma mexicanum) after partial ventricular amputation

array:20 ["pii" => "X1405994010533998" "issn" => "14059940" "estado" => "S300" "fechaPublicacion" => "2010-04-01" "documento" => "article" "crossmark" => 0 "licencia" => "http://www.elsevier.com/open-access/userlicense/1.0/" "subdocumento" => "fla" "cita" => "Arch Cardiol Mex. 2010;80:79-86" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 4968 "formatos" => array:3 [ "EPUB" => 48 "HTML" => 4140 "PDF" => 780 ] ] "itemSiguiente" => array:16 [ "pii" => "X1405994010534009" "issn" => "14059940" "estado" => "S300" "fechaPublicacion" => "2010-04-01" "documento" => "article" "crossmark" => 0 "licencia" => "http://www.elsevier.com/open-access/userlicense/1.0/" "subdocumento" => "fla" "cita" => "Arch Cardiol Mex. 2010;80:87-94" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 8223 "formatos" => array:3 [ "EPUB" => 60 "HTML" => 7529 "PDF" => 634 ] ] "en" => array:12 [ "idiomaDefecto" => true "titulo" => "Surgical repair of congenital mitral valve malformations" "tienePdf" => "en" "tieneTextoCompleto" => "en" "tieneResumen" => array:2 [ 0 => "en" 1 => "es" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "87" "paginaFinal" => "94" ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Reparación quirúrgica de las malformaciones congénitas de la válvula mitral" ] ] "contieneResumen" => array:2 [ "en" => true "es" => true ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:8 [ "identificador" => "fig1" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153400fig1.jpg" "Alto" => 1100 "Ancho" => 1020 "Tamanyo" => 171164 ] ] "descripcion" => array:1 [ "en" => "Schematic diagrams of surgical mitral valve repair techniques and number of cases." ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Pedro Curi-Curi, Samuel Ramírez-Marroquín, Jorge Cervantes-Salazar, Mauricio Soulé, Julio Erdmenger, Juan Calderón-Colmenero" "autores" => array:6 [ 0 => array:2 [ "nombre" => "Pedro" "apellidos" => "Curi-Curi" ] 1 => array:2 [ "nombre" => "Samuel" "apellidos" => "Ramírez-Marroquín" ] 2 => array:2 [ "nombre" => "Jorge" "apellidos" => "Cervantes-Salazar" ] 3 => array:2 [ "nombre" => "Mauricio" "apellidos" => "Soulé" ] 4 => array:2 [ "nombre" => "Julio" "apellidos" => "Erdmenger" ] 5 => array:2 [ "nombre" => "Juan" "apellidos" => "Calderón-Colmenero" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/X1405994010534009?idApp=UINPBA00004N" "url" => "/14059940/0000008000000002/v0_201307091127/X1405994010534009/v0_201307091128/en/main.assets" ] "itemAnterior" => array:16 [ "pii" => "X140599401053398X" "issn" => "14059940" "estado" => "S300" "fechaPublicacion" => "2010-04-01" "documento" => "article" "crossmark" => 0 "licencia" => "http://www.elsevier.com/open-access/userlicense/1.0/" "subdocumento" => "fla" "cita" => "Arch Cardiol Mex. 2010;80:77-8" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 2267 "formatos" => array:3 [ "EPUB" => 53 "HTML" => 1759 "PDF" => 455 ] ] "en" => array:9 [ "idiomaDefecto" => true "titulo" => "Is time for a national multi-institutional mechanical circulatory assistance program?" "tienePdf" => "en" "tieneTextoCompleto" => "en" "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "77" "paginaFinal" => "78" ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "¿Es momento para un programa de asistencia mecánica circulatoria multi-institucional?" ] ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Gustavo Sánchez-Miranda" "autores" => array:1 [ 0 => array:2 [ "nombre" => "Gustavo" "apellidos" => "Sánchez-Miranda" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/X140599401053398X?idApp=UINPBA00004N" "url" => "/14059940/0000008000000002/v0_201307091127/X140599401053398X/v0_201307091127/en/main.assets" ] "en" => array:15 [ "idiomaDefecto" => true "titulo" => "Functional and structural regeneration in the axolotl heart ( Ambystoma mexicanum) after partial ventricular amputation" "tieneTextoCompleto" => true "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "79" "paginaFinal" => "86" ] ] "autores" => array:1 [ 0 => array:3 [ "autoresLista" => "Agustina Cano-Martínez, Alvaro Vargas-González, Verónica Guarner-Lans, Esteban Prado-Zayago, Martha León-Olea, Betzabé Nieto-Lima" "autores" => array:6 [ 0 => array:3 [ "nombre" => "Agustina" "apellidos" => "Cano-Martínez" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "a" "identificador" => "affa" ] ] ] 1 => array:3 [ "nombre" => "Alvaro" "apellidos" => "Vargas-González" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "a" "identificador" => "affa" ] ] ] 2 => array:3 [ "nombre" => "Verónica" "apellidos" => "Guarner-Lans" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "a" "identificador" => "affa" ] ] ] 3 => array:3 [ "nombre" => "Esteban" "apellidos" => "Prado-Zayago" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "b" "identificador" => "affb" ] ] ] 4 => array:3 [ "nombre" => "Martha" "apellidos" => "León-Olea" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "c" "identificador" => "affc" ] ] ] 5 => array:3 [ "nombre" => "Betzabé" "apellidos" => "Nieto-Lima" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "a" "identificador" => "affa" ] ] ] ] "afiliaciones" => array:3 [ 0 => array:3 [ "entidad" => "Departamento de Fisiología, Instituto Nacional de Cardiología Ignacio Chávez." "etiqueta" => "a" "identificador" => "affa" ] 1 => array:3 [ "entidad" => "Criadero Tachipa Umbral, Maya 'Ik Centro. México. " "etiqueta" => "b" "identificador" => "affb" ] 2 => array:3 [ "entidad" => "Instituto Nacional de Psiquiatría Ramón de la Fuente. " "etiqueta" => "c" "identificador" => "affc" ] ] ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Regeneración funcional y estructural del corazón de axolotl ( Ambystoma mexicanum) después de amputación parcial del ventrículo" ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:8 [ "identificador" => "fig1" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig1.jpg" "Alto" => 1341 "Ancho" => 845 "Tamanyo" => 131723 ] ] "descripcion" => array:1 [ "en" => "Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum, in isolated organ assays. Traces correspond to control (a) and to day one (b), five (c), and 30 and 90 (d) after partial ventricular resection. Hearts were maintained in amphibian Ringer, pH 7.8, and the contractile activity was simultaneously recorded for ventricle and atrium at 16+1°C. Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions. A= atrium, V= ventricle, T= tension." ] ] ] "textoCompleto" => "Introduction The amphibian heart is characterized by a single ventricular chamber, an atrium partially separated by a perforated septum1 and the absence of coronary circulation.2,3 The heart of amphibians shows contractile activity with a cyclic pattern of alternating steps of contraction and relaxation. It involves a wave of depolarization created by the cells of the sinus venosus that spreads to contractile cells in the two sides of the atrium, which contract simultaneously. Meanwhile the ventricle is in a state of relaxation that allows it to receive the blood from the atrium. After a short delay, the wave of depolarization reaches the ventricle which contracts and pumps the blood to the pulmonary and systemic circuits, where gases and nutrients can be exchanged. As the ventricle contracts, the cells of the atrium repolarize.4 In contrast to the heart of other vertebrates, the heart of amphibians beats spontaneously for long periods of time in vitro at room temperature,5 which allows the evaluation of the contractile activity of cardiac muscle without the necessity of field stimulation.6-8On the other hand, in contrast to mammals, adult urodele amphibians such as the newt,9,10 axolotl, Ambystoma mexicanum,11,12 and adult zebrafish13,14 restore the structure of myocardial tissue after partial ventricular amputation (PVA). In an ideal situation, structural recovery would result in a fully functional tissue or organ. It is generally assumed that there is a structural restoration, based on the survival time after PVA in newts9,10 and the visual inspection of beating hearts in zebrafish.13 This restoration is related with regeneration and could contribute to the functional reestablishment of the heart function.15 However in none of the cases included, a systematic evaluation of function has been considered. Considering that the functional restoration could be part of the regeneration process, in the present study we evaluated in the adult urodele A. mexicanum the contractile activity of the heart at different time after PVA. Additionally, tissue changes and cardiomyocyte proliferation were evaluated in order to corroborate structural restoration. MethodsAnimals Neotenic adult specimens of A. mexicanum of either sex, aged 8- to 12-months, were used in this study. All animals received adequate care according to the principles of laboratory animal care (NIH publication No. 86-23, revised 1985) and the specific national and institutional laws on protection of animals. The animals were obtained by reproduction in captivity (Breeding place "Tachipa Umbral", Permission SEMARNAP: INE-CITES-DGVS-CR-IN-0249-D.F./97) and were transported to the laboratory where they were maintained at 20 ± 2oC, on a 12 h light/ dark cycle, and fed with living fish ad libitum. Surgical heart injuryAnimals were anaesthetized by placing them in a MS-222 water solution, 1:1000 (w:v) (ICN Biomedicals) and transferred to an ice plate to reduce their metabolic rate. Under aseptic conditions, the heart was exposed through thoracotomy and using microsurgery scissors the ventricular wall was partially resected, reaching the ventricular cavity. The amputated tissue corresponded to the 10 ± 2% of the mean value of total weight of the ventricle. After a blood clot was formed, the wound was cleaned and the incision in the thoracic cavity was closed with a 3-0 silk surgical thread. Sham-operated control organisms were treated in a similar way with the exception of the injury to the ventricular wall. Functional assaySix experimental and 4 sham-operated animals were sacrificed at each specific time (1, 5, 30 and 90 days) after surgery. Each whole heart was placed in an isolated organ chamber5 and perfused with amphibian Ringer solution, pH 7.8, with the following composition (mM): NaCl 111, KCl 1.9, NaHCO3 2.4, NaH2PO4 0.07 and CaCl2 1.1, at 16±1ºC. This temperature was selected considering our previous results for A. dumerilii, in which the reproducibility of the recordings after pharmacological damage was higher when the bath temperature was between 15 and 17ºC.16 The base of the heart was collocated to the bottom of the chamber with a 6-0 surgical thread, whereas the apex was connected to a tension transducer (FTO3 model, Grass, Quincy Mass, USA). A resting tension of 50 to 80 mg was applied to the heart, the cardiac activity was stabilized for 15 to 30 minutes, and spontaneous contractile activity of both the ventricle and atrium was recorded simultaneously in a polygraph (79D model, Grass, Quincy Mass, USA). Isotonic tension and heart rate were evaluated by measuring the amplitude of the spikes and by counting the number of spikes per unit of time in the recording paper, respectively. Structural evaluationMacroscopic structural changes were identified in the hearts previously used in the functional assays. Tissue recovery was detected by Masson's trichrome technique (commercial kit, Accustain Trichrome Stain, Sigma Diagnostics) in subsequent serial and longitudinal frozen sections (10 mm thick). On the other hand, to analyze the cardiomyocyte proliferation, 8 experimental and 4 sham-operated animals for each specific time (5, 10, and 30 days after PVA), received previously their sacrifice 3 administrations of BrdU (250 mg/kg, i.p.) at interval of 24 hr.Animals were sacrificed by decapitation on days 5, 10 and 30 after surgery, hearts were removed, washed, fixed with Carnoy´s solution overnight and equilibrated with 30% sucrose at 4oC. Subsequently, serial and trans-verse frozen sections (10 mm thick) of each heart were obtained and a double immunohistochemistry for BrdU and a-sarcomeric actin was carried. Tissue sections were rehydrated with 0.1 M PBS, pH 7.4, and denatured with 2 N HCl at room temperature for 30 minutes, followed by a double immunohistochemistry for mouse anti-BrdU (Sigma Chemical) and a-sarcomeric actin (a-Sr-1, Dako A/S) antibodies. BrdU and a-sarcomeric actin were indirectly detected by using conjugated donkey anti-mouse IgG-fluoresceine isothiocyanate (FITC; green) and mouse IgG-tetramethyl rhodamine isothiocyanate (TRITC; red), respectively. The proportion of cardiomyocyte with BrdU-labelled nuclei in the damaged area with respect to the total was revealed by DAPI staining. The proportion of BrdU-positive nuclei was determined by counting nuclei in 6 random fields under a 10X objective in 4 tissue sections from the regenerating area of each condition. A total of 1000 to 2500 nuclei were counted for each tissue section. Tissue sections were analyzed by fluorescence (BX51, Olympus) and confocal microscopy (Axiovert 100M, Carl Zeiss). Confocal images were reconstructed from 64 optical sections. Statistical analysisData are presented as mean ± S.D., and the differences between the values of the injured and sham-operated control hearts were established using the Student's t-test. Values of p ≤ 0.05 were considered significant. Results Functional evaluation During spontaneous activity of the hearts of sham-operated adult A. mexicanum, a simultaneous record of ventricle and atrium contractions was obtained, showing a cyclic pattern of a peak from ventricular tension (VT) preceded by a peak from atrium tension (AT) (Figure 1a). Traces of contractile activity of injured hearts are shown in Figures 1b-1d. One day (Figure 1b) and 5 days (Figure 1c) after injury, the form, magnitude (mg) and number of peaks (beats/min) were clearly altered; while at 30 and 90 days (Figure 1d) after resection, values were similar to those of control hearts (Figure 1a). <img src="293v80n02-13153399fig1.jpg" alt="Figure 1. Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum, in isolated organ assays. Traces correspond to control (a) and to day one (b), five (c), and 30 and 90 (d) after partial ventricular resection. Hearts were maintained in amphibian Ringer, pH 7.8, and the contractile activity was simultaneously recorded for ventricle and atrium at 16+1°C. Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions. A= atrium, V= ventricle, T= tension."></img>Figure 1. Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum, in isolated organ assays. Traces correspond to control (a) and to day one (b), five (c), and 30 and 90 (d) after partial ventricular resection. Hearts were maintained in amphibian Ringer, pH 7.8, and the contractile activity was simultaneously recorded for ventricle and atrium at 16+1°C. Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions. A= atrium, V= ventricle, T= tension.Control VT and AT were 62 + 3 and 284 + 15 mg respectively (Figure 2A), while the mean heart rate (HR) of control was 19 + 2 beats/min (Figure 2B). The effect caused by the PVA was detected 1 day after injury as a decrease in the values of VT (84% ± 3), AT (54% ± 4) (Figure 2A) and HR (42% ± 10) in comparison with control heart (Figure 2B). These values returned gradually to those observed in control hearts; achieving a 61 ± 5, 93 ± 3 and 98 ± 5% of the control values for VT; 60 ± 4, 96 ± 3 and 99 ± 5% of the control values for AT (Figure 3A) and 74 ± 5, 84 ± 10 and 95 ± 10% of control values for HR (Figure 3B); on days five, 30 and 90 after injury, respectively. <img src="293v80n02-13153399fig2.jpg" alt="Figure 2. Effect of partial ventricular resection in adult Ambystoma mexicanum on ventricle and atrium tension (A) and heart rate (B) on day one (1d) after partial ventricular resection as compared to control. Contractile activity for ventricle and atrium was recorded simultaneously at 16±1°C. * p ≤ 0.05 when compared to control (C)."></img>Figure 2. Effect of partial ventricular resection in adult Ambystoma mexicanum on ventricle and atrium tension (A) and heart rate (B) on day one (1d) after partial ventricular resection as compared to control. Contractile activity for ventricle and atrium was recorded simultaneously at 16±1°C. * p ≤ 0.05 when compared to control (C).<img src="293v80n02-13153399fig3.jpg" alt="Figure 3. Recovery of tension (A) and heart rate (B) values after partial resection of the ventricle of adult Ambystoma mexicanum as compared to control. Contractile activity for ventricle and atrium was recorded simultaneously at 16°C ± 1. Both tension and heart rate were lower on days one and five after injury. The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury. AT= atrium tension, VT= ventricular tension, * p ≤ 0.05 when compared to control."></img>Figure 3. Recovery of tension (A) and heart rate (B) values after partial resection of the ventricle of adult Ambystoma mexicanum as compared to control. Contractile activity for ventricle and atrium was recorded simultaneously at 16°C ± 1. Both tension and heart rate were lower on days one and five after injury. The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury. AT= atrium tension, VT= ventricular tension, * p ≤ 0.05 when compared to control.Structural evaluationConcomitant with the heart contractile activity we corroborated a gradual tissue restoration (Figure 4). One day after damage, the ventricle showed an evident gap that was covered with a cloth (Figure 4J); after 30 days the hole was partially occupied by compact tissue (Figures 4C, 4G, 4K), and 90 days after injury the heart showed a ventricular wall surface and myocardic tissue similar to control (Figures 4D, 4H, 4L).<img src="293v80n02-13153399fig4.jpg" alt="Figure 4. Representative images of the heart of uninjured adult Ambystoma mexicanum control (A, E, I), and at different times after ventricular partial resection (B, F, J; C, G, K; D, H, L). Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson's trichrome. One day after damage, the ventricle showed an evident gap (F) that was covered with a cloth (J); which is not evident in F because it was removed to photograph; 30 days after injury (G, K) the hole was partially occupied by compact tissue, and 90 days (H, L) after injury the heart showed a ventricular wall surface and myocardial tissue similar to control. A = atrium, c.a = conus arteriosus, V = ventricle. Bar = 1300 mm (A-D) and 1200 mm (E-L). The arrows indicate the zone of resected tissue one day after injury (F, cloth eliminated; J without elimination of cloth) one days after injury, and recovery tissue at day 30 (G and K) and day 90 (H and L) after damage."></img>Figure 4. Representative images of the heart of uninjured adult Ambystoma mexicanum control (A, E, I), and at different times after ventricular partial resection (B, F, J; C, G, K; D, H, L). Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson's trichrome. One day after damage, the ventricle showed an evident gap (F) that was covered with a cloth (J); which is not evident in F because it was removed to photograph; 30 days after injury (G, K) the hole was partially occupied by compact tissue, and 90 days (H, L) after injury the heart showed a ventricular wall surface and myocardial tissue similar to control. A = atrium, c.a = conus arteriosus, V = ventricle. Bar = 1300 mm (A-D) and 1200 mm (E-L). The arrows indicate the zone of resected tissue one day after injury (F, cloth eliminated; J without elimination of cloth) one days after injury, and recovery tissue at day 30 (G and K) and day 90 (H and L) after damage.Colocalization of a-sarcomeric actin staining (Figures 5A, 5D) and BrdU-labelled-nuclei (Figures 5B, 5E) revealed by DAPI staining (Figures 5G-5J), by fluorescence microscopy allowed the identification of BrdU-labelled cardiomyocytes. Five days after injury, the proportion of cardiomyocytes with BrdU-labelled nuclei in the damaged area (Figures 5C, 5F) with respect to the total, was 56 ± 5%. Ten days after injury, this value corresponded to the 32 ± 3% and thirty days after lesion it was the 20 ± 2% of the total. In all cases, cell BrdU-labelled nuclei were surrounded by myocardial cytoplasm, as shown in the image reconstructed from 64 optical sections using confocal microscopy (Figure 6). <img src="293v80n02-13153399fig5.jpg" alt="Figure 5. Fluorescence photomicrographs of double immunostaining for a-sarcomeric actin (TRITC; red), 5-bromo-2'-deoxyuridine (BrdU) (FITC; green) and DAPI (blue) from ventricular myocardium of Ambystoma mexicanum. Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining (A and B), BrdU-positive nuclei in the same fields (B and E) and merged (C, F). Images D, E and F correspond to the in-box marked in A, B and C respectively. Panel II shows the co-staining for asarcomeric actin (A), DAPI (B), BrdU (C) and merged (D). Bar = 100 µm (A-C) and 10 µm (D-J)."></img>Figure 5. Fluorescence photomicrographs of double immunostaining for a-sarcomeric actin (TRITC; red), 5-bromo-2'-deoxyuridine (BrdU) (FITC; green) and DAPI (blue) from ventricular myocardium of Ambystoma mexicanum. Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining (A and B), BrdU-positive nuclei in the same fields (B and E) and merged (C, F). Images D, E and F correspond to the in-box marked in A, B and C respectively. Panel II shows the co-staining for asarcomeric actin (A), DAPI (B), BrdU (C) and merged (D). Bar = 100 µm (A-C) and 10 µm (D-J).<img src="293v80n02-13153399fig6.jpg" alt="Figure 6. Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin (TRITC; red) and 5-bromo-2'-deoxyuridine (BrdU) (FITC; green) immunohistochemistry in ventricular myocardium of Ambystoma mexicanum on day five after surgical injury. The image was reconstructed from 64 optical sections by confocal microscopy. In sections from sham-operated animals, cardiomyocytes with BrdU-labelled nuclei were not found. (A) Frontal view of BrdU-labelled nuclei (arrows) in myocardial fibers (*). View of the myocardial fiber with a rotation of 45, 90 and 180º. In all the cases, nuclei are surrounded by myocardial cytoplasm. Bar = 10 mm. "></img>Figure 6. Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin (TRITC; red) and 5-bromo-2'-deoxyuridine (BrdU) (FITC; green) immunohistochemistry in ventricular myocardium of Ambystoma mexicanum on day five after surgical injury. The image was reconstructed from 64 optical sections by confocal microscopy. In sections from sham-operated animals, cardiomyocytes with BrdU-labelled nuclei were not found. (A) Frontal view of BrdU-labelled nuclei (arrows) in myocardial fibers (*). View of the myocardial fiber with a rotation of 45, 90 and 180º. In all the cases, nuclei are surrounded by myocardial cytoplasm. Bar = 10 mm. Discussion Our results represent the first data concerning about the simultaneous evaluation of the structure and function of the heart of adult A. mexicanum, after surgical injury of the ventricular myocardium. We have obtained evidence showing that the structural recovery of myocardium after ventricular injury in the heart of adult axolotl is accompanied by the restoration of its functional capacity. This finding is in agreement with the proposal that adult organisms of early terrestrial animal species are endowed with a higher capacity of tissue regeneration.17,18Functional assays of the heart of adult A. mexicanum showed a contractile activity with a cyclic pattern of alternating steps of contraction and relaxation, as occurs in the heart of other vertebrates.4 This pattern was markedly disrupted by the PVA. Besides, the capability to develop tension of both ventricle and atrium was significantly decreased (Figures 2 and 3). The heart rate of 19 ± 2 beats/minute, found in control hearts of axolotl, lays within the range of other cardiac rates of other amphibians, which vary from 13 to 23 beats/min.19,20 In our study the decrease in HR (42 ± 6%) in comparison to control (Figures 2B and 3B) at one day of injury, was less dramatic than the fall in tension in the ventricle and atrium (84 ± 2 and 54 ± 4%) (Figure 3A). The force-frequency relationship is an important intrinsic regulatory mechanism of cardiac contractility in which an increase in contractile force is associated with an increase in amplitude,21 however in failing ventricular myocardium this relation is lost. We suggest that the differences in the proportional changes between tension and HR in our study could be a compensatory response in proportion to the tissue and the force-frequency relationship recovery. This might be related to the hypoxic bradycardia, which occurs in lower vertebrates and which could provide a number of direct benefits to the heart when oxygen supply in the spongy myocardium is precarious.22One day after the insult, the effect of PVA was reflected as a more evident decrease in VT (84%) and AT (54%) (Figures 1b and 2A), reflecting that the injured structure was the ventricle. Considering that the function of this structure in vertebrates is to develop the necessary pressure to pump blood to other organs,1,4 its alterations would induce more evident adverse effects. Additionally even when the injury was made in the ventricle, a smaller decrease in the capability of the atrium to develop tension was also observed (Figure 3A), suggesting that the function of other cardiac structures was also altered on the first day as a consequence of the ventricular damage. The progressive reestablishment of the heart rate along with the ventricular- and atrium-tension observed between 30 and 90 days after the PVA, shows that the heart of adult A. mexicanum restore its functional capability when it is impaired by a cardiac damage. Furthermore, as proved later on, this functional restoration is also accompanied by the structural recovery of the heart, which is in accordance with the functional restoration in heart of A. dumerilli after pharmacological heart damage.16Structural evaluation, based on Masson's trichrome results (Figure 4) together with the colocalization of BrdU-labelled nuclei and a-sarcomeric actin, with the surrounding of the BrdU-labelled nuclei by myocar-dial cytoplasm in the heart of A. mexicanun (Figure 6), shows a notorious recovery of the ventricular tissue and the presence of proliferating cardiomyocyte which were more abundant 5 days after PVA. These results are in accordance with the finding of a subset of cardiomyocytes that progress through mitosis and may enter to successive divisions in the newt, other adult urodele amphibian15 and with previous reports that detect BrdU11 and PCNA12 in cardiomyocyte of A. mexicanum. Our finding suggests that cardiomyocyte proliferation could be responsible of the structural recovery detected. However, other mechanisms proposed for tissue regeneration, such as the reprogramming of stem cell23,24 or differentiated cells,25 cannot be ruled out. On the other hand, the reason behind the high regenerative capacity of the heart of adult A. mexicanum is unknown; but it is probably a consequence of the biological characteristics of its cardiac tissue. The heart of adult amphibians consists of spongy, loose and trabecu-late myocardium,26,27 similar to embryonic myocardium of other vertebrates28,29. These characteristics allow the muscle to acquire oxygen by diffusion from luminal blood within the trabecular spaces,30 which would facilitate the supplement of nutrients and growth factors to cardiac cells, which in turn may result in the production of new cardiomyocyte. However, this remains to be analyzed in future studies. Finally, it is relevant to mention that in our study we demonstrated that the heart of A. mexicanum beats spontaneously in vitro for long periods of time at room temperature, as has been found for other amphibians,5,16 this allows the evaluation of the contractile activity of cardiac muscle without the necessity of field stimulation.6-8 Furthermore, the procedure that we used to test functional performance allowed us to register simultaneously the spontaneous activity of both ventricle and atrium, and to assess the intrinsic capacity of the cardiac function independently of the compensatory mechanisms from the rest of the body and avoiding the influence of the anesthetics on cardiac function.31 ConclusionsWe obtained the first quantitative evidence about the recovery of heart contractile activity after PVA in an adult urodele amphibian which indicates that the heart of A. mexicanum restores its functional capacity after PVA in association to cardiomyocyte proliferation. The evaluation of the post-injury changes in the structure and function in the heart of non-mammalian vertebrates, like urodele amphibians, can be very useful, because the proportion of proliferating myocardial cells after damage is very high when compared to mammalian cardiomyocyte, which show a very low ability to proliferate.32 The possibility of an effective myocardial regeneration in A. mexicanum makes it an interesting model to study the mechanisms underlying heart restoration after an insult. Acknowledgements We wish to thank Instituto Nacional de Cardiología Ignacio Chávez for grant 00-303 to ACM and Centro de Instrumentos Hospital de Especialidades C.M.N Siglo XXI (IMSS) for the Carl Zeiss confocal mycroscope facility. <hr></hr>Corresponding author: Agustina Cano Martínez Ph.D. Instituto Nacional de Cardiología Ignacio Chávez, Departamento de Fisiología, Juan Badiano N°1, Colonia Sección XVI, Delegación Tlalpan, CP. 14080, México City, México. Phone: 011 (52) 5573 2911, ext. 1278. E-mail: <a href="mailto:cmamx2002@yahoo.com.mx" class="elsevierStyleCrossRefs">cmamx2002@yahoo.com.mx</a>Received in November 15, 2007; accepted in March 05, 2010." "pdfFichero" => "293v80n02a13153399pdf001.pdf" "tienePdf" => true "PalabrasClave" => array:2 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec192614" "palabras" => array:1 [ 0 => "Amputación parcial del ventrículo; Corazón; Anfibios; Actividad contráctil; Axolotl; Ambystoma; México" ] ] ] "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras clave" "identificador" => "xpalclavsec192613" "palabras" => array:1 [ 0 => "Partial ventricular amputation; Heart, Amphibian; Contractile activity; Axolotl; Ambystoma; Mexico" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "en" => array:1 [ "resumen" => "In the present study we evaluated the effect of partial ventricular amputation (PVA) in the heart of the adult urodele amphibian (Ambystoma mexicanum) in vivo on spontaneous heart contractile activity recorded in vitro in association to the structural recovery at one, five, 30 and 90 days after injury. One day after PVA, ventricular-tension (VT) (16 ± 3%), atrium-tension (AT) (46 ± 4%) and heart rate (HR) (58 ± 10%) resulted lower in comparison to control hearts. On days five, 30 and 90 after damage, values achieved a 61 ± 5, 93 ± 3, and 98 ± 5% (VT), 60 ± 4, 96 ± 3 and 99 ± 5% (AT) and 74 ± 5, 84 ± 10 and 95 ± 10% (HR) of the control values, respectively. Associated to contractile activity recovery we corroborated a gradual tissue restoration by cardiomyocyte proliferation. Our results represent the first quantitative evidence about the recovery of heart contractile activity after PVA in an adult urodele amphibian, indicating that the heart of A. mexicanum restores its functional capacity concomitantly to the structural recovery of the myocardium by proliferation of cardiomyocytes after PVA. These properties make the heart of A. mexicanum a potential model to study the mechanisms underlying heart regeneration in adult vertebrates in vivo." ] "es" => array:1 [ "resumen" => "En el presente estudio evaluamos el efecto de la amputación parcial del ventrículo (APV) del corazón de un anfibio urodelo adulto (Ambystoma mexicanum) in vivo, sobre la actividad contráctil espontánea del corazón registrada in vitro, a diferentes tiempos después de APV, en asociación a su recuperación estructural. Un día después del daño, los valores de tensión ventricular (TV) (16 ± 3%), tensión auricular (TA) (46 + 4%) y frecuencia cardiaca (FC) (58 + 10%), resultaron ser menores respecto al control. En los días cinco, 30 y 90 después del daño, los valores alcanzaron 61 ± 5, 93 ± 3 y 98 ± 5% (TV), 60 ± 4, 96 ± 3 y 99 ± 5% (AT) y 74 ± 5, 84 ± 10 y 95 ± 10% (FC) de los valores control, respectivamente. Además de la recuperación de la actividad contráctil, corroboramos la recuperación estructural y gradual del tejido miocárdico por proliferación de cardiomiocitos. Nuestros resultados representan la primera evidencia cuantitativa de la recuperación de la actividad contráctil del corazón de un anfibio urodelo adulto después de APV; indicando que el corazón de A. mexicanum recupera su capacidad funcional concomitantemente con la recuperación estructural del miocardio por proliferación de cardiomiocitos. El corazón de A. mexicanum es un modelo potencial para el estudio de los mecanismos de la regeneración miocárdica de vertebrados adultos in vivo." ] ] "multimedia" => array:6 [ 0 => array:8 [ "identificador" => "fig1" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig1.jpg" "Alto" => 1341 "Ancho" => 845 "Tamanyo" => 131723 ] ] "descripcion" => array:1 [ "en" => "Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum, in isolated organ assays. Traces correspond to control (a) and to day one (b), five (c), and 30 and 90 (d) after partial ventricular resection. Hearts were maintained in amphibian Ringer, pH 7.8, and the contractile activity was simultaneously recorded for ventricle and atrium at 16+1°C. Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions. A= atrium, V= ventricle, T= tension." ] ] 1 => array:8 [ "identificador" => "fig2" "etiqueta" => "Figure 2" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig2.jpg" "Alto" => 845 "Ancho" => 1854 "Tamanyo" => 64867 ] ] "descripcion" => array:1 [ "en" => "Effect of partial ventricular resection in adult Ambystoma mexicanum on ventricle and atrium tension (A) and heart rate (B) on day one (1d) after partial ventricular resection as compared to control. Contractile activity for ventricle and atrium was recorded simultaneously at 16±1°C. * p ≤ 0.05 when compared to control (C)." ] ] 2 => array:8 [ "identificador" => "fig3" "etiqueta" => "Figure 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig3.jpg" "Alto" => 812 "Ancho" => 1891 "Tamanyo" => 89528 ] ] "descripcion" => array:1 [ "en" => "Recovery of tension (A) and heart rate (B) values after partial resection of the ventricle of adult Ambystoma mexicanum as compared to control. Contractile activity for ventricle and atrium was recorded simultaneously at 16°C ± 1. Both tension and heart rate were lower on days one and five after injury. The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury. AT= atrium tension, VT= ventricular tension, * p ≤ 0.05 when compared to control." ] ] 3 => array:8 [ "identificador" => "fig4" "etiqueta" => "Figure 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig4.jpg" "Alto" => 1687 "Ancho" => 1983 "Tamanyo" => 690244 ] ] "descripcion" => array:1 [ "en" => "Representative images of the heart of uninjured adult Ambystoma mexicanum control (A, E, I), and at different times after ventricular partial resection (B, F, J; C, G, K; D, H, L). Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson's trichrome. One day after damage, the ventricle showed an evident gap (F) that was covered with a cloth (J); which is not evident in F because it was removed to photograph; 30 days after injury (G, K) the hole was partially occupied by compact tissue, and 90 days (H, L) after injury the heart showed a ventricular wall surface and myocardial tissue similar to control. A = atrium, c.a = conus arteriosus, V = ventricle. Bar = 1300 mm (A-D) and 1200 mm (E-L). The arrows indicate the zone of resected tissue one day after injury (F, cloth eliminated; J without elimination of cloth) one days after injury, and recovery tissue at day 30 (G and K) and day 90 (H and L) after damage." ] ] 4 => array:8 [ "identificador" => "fig5" "etiqueta" => "Figure 5" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig5.jpg" "Alto" => 1679 "Ancho" => 1991 "Tamanyo" => 363823 ] ] "descripcion" => array:1 [ "en" => "Fluorescence photomicrographs of double immunostaining for a-sarcomeric actin (TRITC; red), 5-bromo-2'-deoxyuridine (BrdU) (FITC; green) and DAPI (blue) from ventricular myocardium of Ambystoma mexicanum. Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining (A and B), BrdU-positive nuclei in the same fields (B and E) and merged (C, F). Images D, E and F correspond to the in-box marked in A, B and C respectively. Panel II shows the co-staining for asarcomeric actin (A), DAPI (B), BrdU (C) and merged (D). Bar = 100 µm (A-C) and 10 µm (D-J)." ] ] 5 => array:8 [ "identificador" => "fig6" "etiqueta" => "Figure 6" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "copyright" => "Elsevier España" "figura" => array:1 [ 0 => array:4 [ "imagen" => "293v80n02-13153399fig6.jpg" "Alto" => 1512 "Ancho" => 1520 "Tamanyo" => 266906 ] ] "descripcion" => array:1 [ "en" => "Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin (TRITC; red) and 5-bromo-2'-deoxyuridine (BrdU) (FITC; green) immunohistochemistry in ventricular myocardium of Ambystoma mexicanum on day five after surgical injury. The image was reconstructed from 64 optical sections by confocal microscopy. In sections from sham-operated animals, cardiomyocytes with BrdU-labelled nuclei were not found. (A) Frontal view of BrdU-labelled nuclei (arrows) in myocardial fibers (*). View of the myocardial fiber with a rotation of 45, 90 and 180º. In all the cases, nuclei are surrounded by myocardial cytoplasm. Bar = 10 mm." ] ] ] "bibliografia" => array:2 [ "titulo" => "Bibliography" "seccion" => array:1 [ 0 => array:1 [ "bibliografiaReferencia" => array:32 [ 0 => array:3 [ "identificador" => "bib1" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Vertebrates. Comparative anatomy, function, evolution." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Kardong KV." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:2 [ "tituloSerie" => "WCB/McGraw-Hill, Boston Massachusetts, pp" "fecha" => "401, 422-470, 1998" ] ] ] ] ] ] 1 => array:3 [ "identificador" => "bib2" "etiqueta" => "2" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "The cyclo-oxygenase pathway in the avascular heart of the frog, Rana esculenta L." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "Ghiara P" 1 => "Parente L" 2 => "Piomelli D." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Gen Pharmacol 1984" "volumen" => "15" "paginaInicial" => "300" "paginaFinal" => "313" ] ] ] ] ] ] 2 => array:3 [ "identificador" => "bib3" "etiqueta" => "3" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Endocardial endothelium in the avascular frog heart: role for diffusion of NO in control of cardiac O2 consumption." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "Adler A" 1 => "Huang H" 2 => "Wang Z" 3 => "et al." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Am J Physiol Heart Circ Physiol 2004" "volumen" => "287" "paginaInicial" => "14" "paginaFinal" => "21" ] ] ] ] ] ] 3 => array:3 [ "identificador" => "bib4" "etiqueta" => "4" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "The heart: physiology, from cell to circulation." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Opie LH." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:2 [ "tituloSerie" => "Lippincott-Raven, Philadelphia, pp" "fecha" => "343-389, 1998" ] ] ] ] ] ] 4 => array:3 [ "identificador" => "bib5" "etiqueta" => "5" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Pharmacological Experiments on Intact Preparation." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "MacLeod LJ." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:2 [ "tituloSerie" => "Churchill Livingstone, Edinburgh, pp" "fecha" => "113, 1970" ] ] ] ] ] ] 5 => array:3 [ "identificador" => "bib6" "etiqueta" => "6" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Cardiac beta2-adrenoceptor in the frog." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "Stene-Larsen G" 1 => "Helle KB." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Comp Biochem Physiol 1978" "volumen" => "60C" "paginaInicial" => "165" "paginaFinal" => "173" ] ] ] ] ] ] 6 => array:3 [ "identificador" => "bib7" "etiqueta" => "7" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Ericson LE, Poupa O." "idioma" => "pt" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Carlsten A." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:1 [ "tituloSerie" => "The healing of frog heart lesions induced by isoproterenol injections" ] ] ] ] ] ] 7 => array:3 [ "identificador" => "bib8" "etiqueta" => "8" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Hypoxia and ischemia in buffer-perfused toad hearts." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "McKean T." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "J Exp Biol 1997" "volumen" => "200" "paginaInicial" => "2575" "paginaFinal" => "2581" ] ] ] ] ] ] 8 => array:3 [ "identificador" => "bib9" "etiqueta" => "9" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Regeneration of ventricular myocardium in amphibians." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "Becker RO" 1 => "Chapin S" 2 => "Sherry R." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Nature 1974" "volumen" => "248" "paginaInicial" => "145" "paginaFinal" => "147" ] ] ] ] ] ] 9 => array:3 [ "identificador" => "bib10" "etiqueta" => "10" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Response of the adult newt ventricle to injury." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "Oberpriller JO" 1 => "Oberpriller JC." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "J Exp Zool 1974" "volumen" => "187" "paginaInicial" => "249" "paginaFinal" => "260" ] ] ] ] ] ] 10 => array:3 [ "identificador" => "bib11" "etiqueta" => "11" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Cell cycle reentry of ventricular and atrial cardiomyocytes and cells within the epicardium following amputation of the ventricular apex in the axolotl, Amblystoma mexicanum: confocal microscopic immunofluorescent image analysis of bromodeoxyuridine-labeled nuclei." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Flink IL." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Anat Embryol 2002" "volumen" => "205" "paginaInicial" => "235" "paginaFinal" => "244" ] ] ] ] ] ] 11 => array:3 [ "identificador" => "bib12" "etiqueta" => "12" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Regeneración miocárdica en Ambystoma mexicanum después de lesión quirúrgica." "idioma" => "es" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "Vargas GA" 1 => "Prado ZE" 2 => "León OM" 3 => "et al." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Arch Cardiol Mex 2005" "volumen" => "75" "paginaInicial" => "21" "paginaFinal" => "29" ] ] ] ] ] ] 12 => array:3 [ "identificador" => "bib13" "etiqueta" => "13" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Heart regeneration in zebrafish." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "Poss KD" 1 => "Wilson LG" 2 => "Keating MT." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Science 2002" "volumen" => "298" "paginaInicial" => "2188" "paginaFinal" => "2190" ] ] ] ] ] ] 13 => array:3 [ "identificador" => "bib14" "etiqueta" => "14" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Getting to the heart of regereration in zebrafish." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Poss KD." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Semin" "fecha" => "Cell Dev Biol 2007" "volumen" => "18" "paginaInicial" => "36" "paginaFinal" => "45" ] ] ] ] ] ] 14 => array:3 [ "identificador" => "bib15" "etiqueta" => "15" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Heterogeneous proliferative potential in regenerative adult newt cardiomyocytes." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "Bettencourt DM" 1 => "Mittnacht S" 2 => "Brockes JP." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "J Cell Sci 2003" "volumen" => "116" "paginaInicial" => "4001" "paginaFinal" => "4009" ] ] ] ] ] ] 15 => array:3 [ "identificador" => "bib16" "etiqueta" => "16" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Temperature effect on contractile activity of the Ambystoma dumerilii heart previously treated with isoproterenol." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "Cano MA" 1 => "Vargas GA" 2 => "Guarner LV." ] ] ] ] ] "host" => array:1 [ 0 => null ] ] ] ] 16 => array:3 [ "identificador" => "bib17" "etiqueta" => "17" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Regeneration through phylogenesis: cellular and molecular basis of regeneration. In: Ferretti P. Géraudie JJ (Eds). From invertebrates to humans." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "Thouveny Y" 1 => "Tassava R." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:2 [ "tituloSerie" => "Wiley and Sons, New York, pp" "fecha" => "9-43, 1998" ] ] ] ] ] ] 17 => array:3 [ "identificador" => "bib18" "etiqueta" => "18" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Regeneration in vertebrates." "idioma" => "de" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Tsonis P." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:2 [ "fecha" => "Dev Biol 2000" "volumen" => "221 273-284" ] ] ] ] ] ] 18 => array:3 [ "identificador" => "bib19" "etiqueta" => "19" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Autonomic influences on heart rate and blood pressure in the toad, Bufo marinus, at rest and during exercise." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "Wahlqvist I" 1 => "Campbell G." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "J Exp Biol 1988" "volumen" => "134" "paginaInicial" => "377" "paginaFinal" => "396" ] ] ] ] ] ] 19 => array:3 [ "identificador" => "bib20" "etiqueta" => "20" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Resting heart rate of the toad Bufo marinus: a long term study of individual differences and environmental influences." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Dumsday B." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Physiol Zool 1990" "volumen" => "63" "paginaInicial" => "420" "paginaFinal" => "431" ] ] ] ] ] ] 20 => array:3 [ "identificador" => "bib21" "etiqueta" => "21" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Force-frequency relationship in intact mammalian ventricular myocardium: physiological and pathophysiological relevance." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Edoh M." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Eur J Pharmacol 2004" "volumen" => "500" "paginaInicial" => "73" "paginaFinal" => "86" ] ] ] ] ] ] 21 => array:3 [ "identificador" => "bib22" "etiqueta" => "22" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Tribute to P. L." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Farrell AP." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Lutz: a message from the heart--why hypoxic bradycardia in fishes?" "fecha" => "J Exp Biol 2007" "volumen" => "210" "paginaInicial" => "1715" "paginaFinal" => "1725" ] ] ] ] ] ] 22 => array:3 [ "identificador" => "bib23" "etiqueta" => "23" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Nuclear reprogramming: a key to stem cell function in regenerative medicine." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "Pomerantz J" 1 => "Blau HM." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Nat Cell Biol 2004" "volumen" => "6" "paginaInicial" => "810" "paginaFinal" => "816" ] ] ] ] ] ] 23 => array:3 [ "identificador" => "bib24" "etiqueta" => "24" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Re-programming of newt cardiomyocytes is induced by tissue regeneration." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "Laube F" 1 => "Heister M" 2 => "Scholtz C" 3 => "et al." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "J Cell Sci 2006" "volumen" => "199" "paginaInicial" => "4719" "paginaFinal" => "4729" ] ] ] ] ] ] 24 => array:3 [ "identificador" => "bib25" "etiqueta" => "25" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Plasticity and reprogramming of differentiated cells in amphibian regeneration: partial purification of a serum factor that triggers cell cycle re-entry in differentiated muscle cells." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "Straube WL" 1 => "Brockes JP" 2 => "Drechsel DN" 3 => "et al." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Cloning Stem Cells 2004" "volumen" => "6" "paginaInicial" => "333" "paginaFinal" => "344" ] ] ] ] ] ] 25 => array:3 [ "identificador" => "bib26" "etiqueta" => "26" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Blood supply of the compact and spongy myocardium of fish, amphibia and reptiles." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Romenskii O." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Arkh Anat Gistol Embriol 1978" "volumen" => "75" "paginaInicial" => "91" "paginaFinal" => "95" ] ] ] ] ] ] 26 => array:3 [ "identificador" => "bib27" "etiqueta" => "27" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Evolution of the ventricles." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Victor S." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Tex Heart Inst J 1999" "volumen" => "26" "paginaInicial" => "168" "paginaFinal" => "175" ] ] ] ] ] ] 27 => array:3 [ "identificador" => "bib28" "etiqueta" => "28" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Ventricular trabeculations in the chick embryo heart and their contribution to ventricular and muscular septal development." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Ben-Shachar G." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Circ Res 1985" "volumen" => "57" "paginaInicial" => "759" "paginaFinal" => "766" ] ] ] ] ] ] 28 => array:3 [ "identificador" => "bib29" "etiqueta" => "29" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Developmental patterning of the myocardium." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "Sedmera D" 1 => "Pexieder T" 2 => "Vuillemin M" 3 => "et al." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "fecha" => "Anat Rec 2000" "volumen" => "258" "paginaInicial" => "319" "paginaFinal" => "337" "itemHostRev" => array:3 [ "pii" => "S1462388909000982" "estado" => "S300" "issn" => "14623889" ] ] ] ] ] ] ] 29 => array:3 [ "identificador" => "bib30" "etiqueta" => "30" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Resting and maximal heart rates in ectothermic vertebrates." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "Lillywhite HB" 1 => "Zippel KC" 2 => "Farrell AP." ] ] ] ] ] "host" => array:1 [ 0 => null ] ] ] ] 30 => array:3 [ "identificador" => "bib31" "etiqueta" => "31" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Sympathetic cardiac stimulation in Bufo marinus under MS-222 anesthesia." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Smith DG." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:4 [ "fecha" => "Am J Physiol 1974" "volumen" => "226" "paginaInicial" => "367" "paginaFinal" => "370" ] ] ] ] ] ] 31 => array:3 [ "identificador" => "bib32" "etiqueta" => "32" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:3 [ "titulo" => "Cardiomyocyte proliferation: a platform for mammalian cardiac repair." "idioma" => "en" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "Engel FB." ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "fecha" => "Cell Cycle 2005" "volumen" => "4" "paginaInicial" => "1360" "paginaFinal" => "1363" "itemHostRev" => array:3 [ "pii" => "S0959804911004679" "estado" => "S300" "issn" => "09598049" ] ] ] ] ] ] ] ] ] ] ] ] "idiomaDefecto" => "en" "url" => "/14059940/0000008000000002/v0_201307091127/X1405994010533998/v0_201307091127/en/main.assets" "Apartado" => array:4 [ "identificador" => "14673" "tipo" => "SECCION" "es" => array:2 [ "titulo" => "Investigación básica" "idiomaDefecto" => true ] "idiomaDefecto" => "es" ] "PDF" => "https://static.elsevier.es/multimedia/14059940/0000008000000002/v0_201307091127/X1405994010533998/v0_201307091127/en/293v80n02a13153399pdf001.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/X1405994010533998?idApp=UINPBA00004N"]

Statistics

Regeneración funcional y estructural del corazón de axolotl ( Ambystoma mexicanum) después de amputación parcial del ventrículo

Agustina Cano-Martíneza, Alvaro Vargas-Gonzáleza, Verónica Guarner-Lansa, Esteban Prado-Zayagob, Martha León-Oleac, Betzabé Nieto-Limaa

a Departamento de Fisiología, Instituto Nacional de Cardiología Ignacio Chávez.

b Criadero Tachipa Umbral, Maya 'Ik Centro. México.

c Instituto Nacional de Psiquiatría Ramón de la Fuente.

Read

10189

Times
was read the article

1476

Total PDF

8713

Total HTML

Share statistics

 array:20 [
  "pii" => "X1405994010533998"
  "issn" => "14059940"
  "estado" => "S300"
  "fechaPublicacion" => "2010-04-01"
  "documento" => "article"
  "crossmark" => 0
  "licencia" => "http://www.elsevier.com/open-access/userlicense/1.0/"
  "subdocumento" => "fla"
  "cita" => "Arch Cardiol Mex. 2010;80:79-86"
  "abierto" => array:3 [
    "ES" => true
    "ES2" => true
    "LATM" => true
  ]
  "gratuito" => true
  "lecturas" => array:2 [
    "total" => 4968
    "formatos" => array:3 [
      "EPUB" => 48
      "HTML" => 4140
      "PDF" => 780
    ]
  ]
  "itemSiguiente" => array:16 [
    "pii" => "X1405994010534009"
    "issn" => "14059940"
    "estado" => "S300"
    "fechaPublicacion" => "2010-04-01"
    "documento" => "article"
    "crossmark" => 0
    "licencia" => "http://www.elsevier.com/open-access/userlicense/1.0/"
    "subdocumento" => "fla"
    "cita" => "Arch Cardiol Mex. 2010;80:87-94"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:2 [
      "total" => 8223
      "formatos" => array:3 [
        "EPUB" => 60
        "HTML" => 7529
        "PDF" => 634
      ]
    ]
    "en" => array:12 [
      "idiomaDefecto" => true
      "titulo" => "Surgical repair of congenital mitral valve malformations"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => array:2 [
        0 => "en"
        1 => "es"
      ]
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "87"
          "paginaFinal" => "94"
        ]
      ]
      "titulosAlternativos" => array:1 [
        "es" => array:1 [
          "titulo" => "Reparaci&#243;n quir&#250;rgica de las malformaciones cong&#233;nitas de la v&#225;lvula mitral"
        ]
      ]
      "contieneResumen" => array:2 [
        "en" => true
        "es" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:8 [
          "identificador" => "fig1"
          "etiqueta" => "Figure 1"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "copyright" => "Elsevier Espa&#241;a"
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "293v80n02-13153400fig1.jpg"
              "Alto" => 1100
              "Ancho" => 1020
              "Tamanyo" => 171164
            ]
          ]
          "descripcion" => array:1 [
            "en" => "Schematic diagrams of surgical mitral valve repair techniques and number of cases&#46;"
          ]
        ]
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "Pedro Curi-Curi, Samuel Ram&#237;rez-Marroqu&#237;n, Jorge Cervantes-Salazar, Mauricio Soul&#233;, Julio Erdmenger, Juan Calder&#243;n-Colmenero"
          "autores" => array:6 [
            0 => array:2 [
              "nombre" => "Pedro"
              "apellidos" => "Curi-Curi"
            ]
            1 => array:2 [
              "nombre" => "Samuel"
              "apellidos" => "Ram&#237;rez-Marroqu&#237;n"
            ]
            2 => array:2 [
              "nombre" => "Jorge"
              "apellidos" => "Cervantes-Salazar"
            ]
            3 => array:2 [
              "nombre" => "Mauricio"
              "apellidos" => "Soul&#233;"
            ]
            4 => array:2 [
              "nombre" => "Julio"
              "apellidos" => "Erdmenger"
            ]
            5 => array:2 [
              "nombre" => "Juan"
              "apellidos" => "Calder&#243;n-Colmenero"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/X1405994010534009?idApp=UINPBA00004N"
    "url" => "/14059940/0000008000000002/v0_201307091127/X1405994010534009/v0_201307091128/en/main.assets"
  ]
  "itemAnterior" => array:16 [
    "pii" => "X140599401053398X"
    "issn" => "14059940"
    "estado" => "S300"
    "fechaPublicacion" => "2010-04-01"
    "documento" => "article"
    "crossmark" => 0
    "licencia" => "http://www.elsevier.com/open-access/userlicense/1.0/"
    "subdocumento" => "fla"
    "cita" => "Arch Cardiol Mex. 2010;80:77-8"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:2 [
      "total" => 2267
      "formatos" => array:3 [
        "EPUB" => 53
        "HTML" => 1759
        "PDF" => 455
      ]
    ]
    "en" => array:9 [
      "idiomaDefecto" => true
      "titulo" => "Is time for a national multi-institutional mechanical circulatory assistance program&#63;"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "77"
          "paginaFinal" => "78"
        ]
      ]
      "titulosAlternativos" => array:1 [
        "es" => array:1 [
          "titulo" => "&#191;Es momento para un programa de asistencia mec&#225;nica circulatoria multi-institucional&#63;"
        ]
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "Gustavo S&#225;nchez-Miranda"
          "autores" => array:1 [
            0 => array:2 [
              "nombre" => "Gustavo"
              "apellidos" => "S&#225;nchez-Miranda"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/X140599401053398X?idApp=UINPBA00004N"
    "url" => "/14059940/0000008000000002/v0_201307091127/X140599401053398X/v0_201307091127/en/main.assets"
  ]
  "en" => array:15 [
    "idiomaDefecto" => true
    "titulo" => "Functional and structural regeneration in the axolotl heart &#40; <span class="elsevierStyleItalic">Ambystoma mexicanum</span>&#41; after partial ventricular amputation"
    "tieneTextoCompleto" => true
    "paginas" => array:1 [
      0 => array:2 [
        "paginaInicial" => "79"
        "paginaFinal" => "86"
      ]
    ]
    "autores" => array:1 [
      0 => array:3 [
        "autoresLista" => "Agustina Cano-Mart&#237;nez, Alvaro Vargas-Gonz&#225;lez, Ver&#243;nica Guarner-Lans, Esteban Prado-Zayago, Martha Le&#243;n-Olea, Betzab&#233; Nieto-Lima"
        "autores" => array:6 [
          0 => array:3 [
            "nombre" => "Agustina"
            "apellidos" => "Cano-Mart&#237;nez"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "affa"
              ]
            ]
          ]
          1 => array:3 [
            "nombre" => "Alvaro"
            "apellidos" => "Vargas-Gonz&#225;lez"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "affa"
              ]
            ]
          ]
          2 => array:3 [
            "nombre" => "Ver&#243;nica"
            "apellidos" => "Guarner-Lans"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "affa"
              ]
            ]
          ]
          3 => array:3 [
            "nombre" => "Esteban"
            "apellidos" => "Prado-Zayago"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">b</span>"
                "identificador" => "affb"
              ]
            ]
          ]
          4 => array:3 [
            "nombre" => "Martha"
            "apellidos" => "Le&#243;n-Olea"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">c</span>"
                "identificador" => "affc"
              ]
            ]
          ]
          5 => array:3 [
            "nombre" => "Betzab&#233;"
            "apellidos" => "Nieto-Lima"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "affa"
              ]
            ]
          ]
        ]
        "afiliaciones" => array:3 [
          0 => array:3 [
            "entidad" => "Departamento de Fisiología, Instituto Nacional de Cardiología Ignacio Chávez."
            "etiqueta" => "<span class="elsevierStyleSup">a</span>"
            "identificador" => "affa"
          ]
          1 => array:3 [
            "entidad" => "Criadero Tachipa Umbral, Maya 'Ik Centro. México. "
            "etiqueta" => "<span class="elsevierStyleSup">b</span>"
            "identificador" => "affb"
          ]
          2 => array:3 [
            "entidad" => "Instituto Nacional de Psiquiatría Ramón de la Fuente. "
            "etiqueta" => "<span class="elsevierStyleSup">c</span>"
            "identificador" => "affc"
          ]
        ]
      ]
    ]
    "titulosAlternativos" => array:1 [
      "es" => array:1 [
        "titulo" => "Regeneraci&#243;n funcional y estructural del coraz&#243;n de axolotl &#40; <span class="elsevierStyleItalic">Ambystoma mexicanum</span>&#41; despu&#233;s de amputaci&#243;n parcial del ventr&#237;culo"
      ]
    ]
    "resumenGrafico" => array:2 [
      "original" => 0
      "multimedia" => array:8 [
        "identificador" => "fig1"
        "etiqueta" => "Figure 1"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig1.jpg"
            "Alto" => 1341
            "Ancho" => 845
            "Tamanyo" => 131723
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum&#44; in isolated organ assays&#46; Traces correspond to control &#40;a&#41; and to day one &#40;b&#41;&#44; five &#40;c&#41;&#44; and 30 and 90 &#40;d&#41; after partial ventricular resection&#46; Hearts were maintained in amphibian Ringer&#44; pH 7&#46;8&#44; and the contractile activity was simultaneously recorded for ventricle and atrium at 16&#43;1&#176;C&#46; Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions&#46; A&#61; atrium&#44; V&#61; ventricle&#44; T&#61; tension&#46;"
        ]
      ]
    ]
    "textoCompleto" => "<p class="elsevierStylePara"><span class="elsevierStyleBold">Introduction </span></p><p class="elsevierStylePara">The amphibian heart is characterized by a single ventricular chamber&#44; an atrium partially separated by a perforated septum<span class="elsevierStyleSup">1</span> and the absence of coronary circulation&#46;<span class="elsevierStyleSup">2&#44;3</span> The heart of amphibians shows contractile activity with a cyclic pattern of alternating steps of contraction and relaxation&#46; It involves a wave of depolarization created by the cells of the <span class="elsevierStyleItalic">sinus venosus</span> that spreads to contractile cells in the two sides of the atrium&#44; which contract simultaneously&#46; Meanwhile the ventricle is in a state of relaxation that allows it to receive the blood from the atrium&#46; After a short delay&#44; the wave of depolarization reaches the ventricle which contracts and pumps the blood to the pulmonary and systemic circuits&#44; where gases and nutrients can be exchanged&#46; As the ventricle contracts&#44; the cells of the atrium repolarize&#46;<span class="elsevierStyleSup">4</span> In contrast to the heart of other vertebrates&#44; the heart of amphibians beats spontaneously for long periods of time <span class="elsevierStyleItalic">in vitro</span> at room temperature&#44;<span class="elsevierStyleSup">5 </span>which allows the evaluation of the contractile activity of cardiac muscle without the necessity of field stimulation&#46;<span class="elsevierStyleSup">6-8</span></p><p class="elsevierStylePara">On the other hand&#44; in contrast to mammals&#44; adult urodele amphibians such as the newt&#44;<span class="elsevierStyleSup">9&#44;10</span> axolotl&#44; <span class="elsevierStyleItalic">Ambystoma mexicanum&#44;</span><span class="elsevierStyleSup">11&#44;12</span> and adult zebrafish<span class="elsevierStyleSup">13&#44;14 </span>restore the structure of myocardial tissue after partial ventricular amputation &#40;PVA&#41;&#46; In an ideal situation&#44; structural recovery would result in a fully functional tissue or organ&#46; It is generally assumed that there is a structural restoration&#44; based on the survival time after PVA in newts<span class="elsevierStyleSup">9&#44;10 </span>and the visual inspection of beating hearts in zebrafish&#46;<span class="elsevierStyleSup">13</span> This restoration is related with regeneration and could contribute to the functional reestablishment of the heart function&#46;<span class="elsevierStyleSup">15</span> However in none of the cases included&#44; a systematic evaluation of function has been considered&#46; Considering that the functional restoration could be part of the regeneration process&#44; in the present study we evaluated in the adult urodele <span class="elsevierStyleItalic">A&#46; mexicanum</span> the contractile activity of the heart at different time after PVA&#46; Additionally&#44; tissue changes and cardiomyocyte proliferation were evaluated in order to corroborate structural restoration&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Methods</span></p><p class="elsevierStylePara"><span class="elsevierStyleItalic">Animals </span></p><p class="elsevierStylePara">Neotenic adult specimens of <span class="elsevierStyleItalic">A&#46; mexicanum</span> of either sex&#44; aged 8- to 12-months&#44; were used in this study&#46; All animals received adequate care according to the principles of laboratory animal care &#40;NIH publication No&#46; 86-23&#44; revised 1985&#41; and the specific national and institutional laws on protection of animals&#46; The animals were obtained by reproduction in captivity &#40;Breeding place &#34;Tachipa Umbral&#34;&#44; Permission SEMARNAP&#58; INE-CITES-DGVS-CR-IN-0249-D&#46;F&#46;&#47;97&#41; and were transported to the laboratory where they were maintained at 20 &#177; 2<span class="elsevierStyleSup">o</span>C&#44; on a 12 h light&#47; dark cycle&#44; and fed with living fish ad libitum&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Surgical heart injury</span></p><p class="elsevierStylePara">Animals were anaesthetized by placing them in a MS-222 water solution&#44; 1&#58;1000 &#40;w&#58;v&#41; &#40;ICN Biomedicals&#41; and transferred to an ice plate to reduce their metabolic rate&#46; Under aseptic conditions&#44; the heart was exposed through thoracotomy and using microsurgery scissors the ventricular wall was partially resected&#44; reaching the ventricular cavity&#46; The amputated tissue corresponded to the 10 &#177; 2&#37; of the mean value of total weight of the ventricle&#46; After a blood clot was formed&#44; the wound was cleaned and the incision in the thoracic cavity was closed with a 3-0 silk surgical thread&#46; Sham-operated control organisms were treated in a similar way with the exception of the injury to the ventricular wall&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Functional assay</span></p><p class="elsevierStylePara">Six experimental and 4 sham-operated animals were sacrificed at each specific time &#40;1&#44; 5&#44; 30 and 90 days&#41; after surgery&#46; Each whole heart was placed in an isolated organ chamber<span class="elsevierStyleSup">5</span> and perfused with amphibian Ringer solution&#44; pH 7&#46;8&#44; with the following composition &#40;mM&#41;&#58; NaCl 111&#44; KCl 1&#46;9&#44; NaHCO<span class="elsevierStyleInf">3</span> 2&#46;4&#44; NaH<span class="elsevierStyleInf">2</span>PO<span class="elsevierStyleInf">4</span> 0&#46;07 and CaCl<span class="elsevierStyleInf">2 </span>1&#46;1&#44; at 16&#177;1&#186;C&#46; This temperature was selected considering our previous results for <span class="elsevierStyleItalic">A&#46; dumerilii</span>&#44; in which the reproducibility of the recordings after pharmacological damage was higher when the bath temperature was between 15 and 17&#186;C&#46;<span class="elsevierStyleSup">16</span> The base of the heart was collocated to the bottom of the chamber with a 6-0 surgical thread&#44; whereas the apex was connected to a tension transducer &#40;FTO3 model&#44; Grass&#44; Quincy Mass&#44; USA&#41;&#46; A resting tension of 50 to 80 mg was applied to the heart&#44; the cardiac activity was stabilized for 15 to 30 minutes&#44; and spontaneous contractile activity of both the ventricle and atrium was recorded simultaneously in a polygraph &#40;79D model&#44; Grass&#44; Quincy Mass&#44; USA&#41;&#46; Isotonic tension and heart rate were evaluated by measuring the amplitude of the spikes and by counting the number of spikes per unit of time in the recording paper&#44; respectively&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Structural evaluation</span></p><p class="elsevierStylePara">Macroscopic structural changes were identified in the hearts previously used in the functional assays&#46; Tissue recovery was detected by Masson&#39;s trichrome technique &#40;commercial kit&#44; Accustain Trichrome Stain&#44; Sigma Diagnostics&#41; in subsequent serial and longitudinal frozen sections &#40;10 mm thick&#41;&#46; </p><p class="elsevierStylePara">On the other hand&#44; to analyze the cardiomyocyte proliferation&#44; 8 experimental and 4 sham-operated animals for each specific time &#40;5&#44; 10&#44; and 30 days after PVA&#41;&#44; received previously their sacrifice 3 administrations of BrdU &#40;250 mg&#47;kg&#44; i&#46;p&#46;&#41; at interval of 24 hr&#46;</p><p class="elsevierStylePara">Animals were sacrificed by decapitation on days 5&#44; 10 and 30 after surgery&#44; hearts were removed&#44; washed&#44; fixed with Carnoy&#180;s solution overnight and equilibrated with 30&#37; sucrose at 4<span class="elsevierStyleSup">o</span>C&#46; Subsequently&#44; serial and trans-verse frozen sections &#40;10 mm thick&#41; of each heart were obtained and a double immunohistochemistry for BrdU and a-sarcomeric actin was carried&#46; Tissue sections were rehydrated with 0&#46;1 M PBS&#44; pH 7&#46;4&#44; and denatured with 2 N HCl at room temperature for 30 minutes&#44; followed by a double immunohistochemistry for mouse anti-BrdU &#40;Sigma Chemical&#41; and a-sarcomeric actin &#40;a-Sr-1&#44; Dako A&#47;S&#41; antibodies&#46; BrdU and a-sarcomeric actin were indirectly detected by using conjugated donkey anti-mouse IgG-fluoresceine isothiocyanate &#40;FITC&#59; green&#41; and mouse IgG-tetramethyl rhodamine isothiocyanate &#40;TRITC&#59; red&#41;&#44; respectively&#46; The proportion of cardiomyocyte with BrdU-labelled nuclei in the damaged area with respect to the total was revealed by DAPI staining&#46; The proportion of BrdU-positive nuclei was determined by counting nuclei in 6 random fields under a 10X objective in 4 tissue sections from the regenerating area of each condition&#46; A total of 1000 to 2500 nuclei were counted for each tissue section&#46; </p><p class="elsevierStylePara">Tissue sections were analyzed by fluorescence &#40;BX51&#44; Olympus&#41; and confocal microscopy &#40;Axiovert 100M&#44; Carl Zeiss&#41;&#46; Confocal images were reconstructed from 64 optical sections&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Statistical analysis</span></p><p class="elsevierStylePara">Data are presented as mean &#177; S&#46;D&#46;&#44; and the differences between the values of the injured and sham-operated control hearts were established using the Student&#39;s t-test&#46; Values of p &#8804; 0&#46;05 were considered significant&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Results </span></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Functional evaluation </span></p><p class="elsevierStylePara">During spontaneous activity of the hearts of sham-operated adult <span class="elsevierStyleItalic">A&#46; mexicanum</span>&#44; a simultaneous record of ventricle and atrium contractions was obtained&#44; showing a cyclic pattern of a peak from ventricular tension &#40;VT&#41; preceded by a peak from atrium tension &#40;AT&#41; &#40;<span class="elsevierStyleBold">Figure 1a</span>&#41;&#46; Traces of contractile activity of injured hearts are shown in <span class="elsevierStyleBold">Figures 1b-1d</span>&#46; One day &#40;<span class="elsevierStyleBold">Figure 1b</span>&#41; and 5 days &#40;<span class="elsevierStyleBold">Figure 1c</span>&#41; after injury&#44; the form&#44; magnitude &#40;mg&#41; and number of peaks &#40;beats&#47;min&#41; were clearly altered&#59; while at 30 and 90 days &#40;<span class="elsevierStyleBold">Figure 1d</span>&#41; after resection&#44; values were similar to those of control hearts &#40;<span class="elsevierStyleBold">Figure 1a</span>&#41;&#46; </p><p class="elsevierStylePara"><img src="293v80n02-13153399fig1.jpg" alt="Figure 1&#46; Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum&#44; in isolated organ assays&#46; Traces correspond to control &#40;a&#41; and to day one &#40;b&#41;&#44; five &#40;c&#41;&#44; and 30 and 90 &#40;d&#41; after partial ventricular resection&#46; Hearts were maintained in amphibian Ringer&#44; pH 7&#46;8&#44; and the contractile activity was simultaneously recorded for ventricle and atrium at 16&#43;1&#176;C&#46; Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions&#46; A&#61; atrium&#44; V&#61; ventricle&#44; T&#61; tension&#46;"></img></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Figure 1&#46; </span>Representative traces of spontaneously developed contractile activity of the whole heart of adult <span class="elsevierStyleItalic">Ambystoma mexicanum</span>&#44; in isolated organ assays&#46; Traces correspond to control &#40;a&#41; and to day one &#40;b&#41;&#44; five &#40;c&#41;&#44; and 30 and 90 &#40;d&#41; after partial ventricular resection&#46; Hearts were maintained in amphibian Ringer&#44; pH 7&#46;8&#44; and the contractile activity was simultaneously recorded for ventricle and atrium at 16&#43;1&#176;C&#46; Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions&#46; A&#61; atrium&#44; V&#61; ventricle&#44; T&#61; tension&#46;</p><p class="elsevierStylePara">Control VT and AT were 62 &#43; 3 and 284 &#43; 15 mg respectively &#40;<span class="elsevierStyleBold">Figure 2A</span>&#41;&#44; while the mean heart rate &#40;HR&#41; of control was 19 &#43; 2 beats&#47;min &#40;<span class="elsevierStyleBold">Figure 2B</span>&#41;&#46; The effect caused by the PVA was detected 1 day after injury as a decrease in the values of VT &#40;84&#37; &#177; 3&#41;&#44; AT &#40;54&#37; &#177; 4&#41; &#40;<span class="elsevierStyleBold">Figure 2A</span>&#41; and HR &#40;42&#37; &#177; 10&#41; in comparison with control heart &#40;<span class="elsevierStyleBold">Figure 2B</span>&#41;&#46; These values returned gradually to those observed in control hearts&#59; achieving a 61 &#177; 5&#44; 93 &#177; 3 and 98 &#177; 5&#37; of the control values for VT&#59; 60 &#177; 4&#44; 96 &#177; 3 and 99 &#177; 5&#37; of the control values for AT &#40;<span class="elsevierStyleBold">Figure 3A</span>&#41; and 74 &#177; 5&#44; 84 &#177; 10 and 95 &#177; 10&#37; of control values for HR &#40;<span class="elsevierStyleBold">Figure 3B</span>&#41;&#59; on days five&#44; 30 and 90 after injury&#44; respectively&#46; </p><p class="elsevierStylePara"><img src="293v80n02-13153399fig2.jpg" alt="Figure 2&#46; Effect of partial ventricular resection in adult Ambystoma mexicanum on ventricle and atrium tension &#40;A&#41; and heart rate &#40;B&#41; on day one &#40;1d&#41; after partial ventricular resection as compared to control&#46; Contractile activity for ventricle and atrium was recorded simultaneously at 16&#177;1&#176;C&#46; &#42; p &#8804; 0&#46;05 when compared to control &#40;C&#41;&#46;"></img></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Figure 2&#46;</span> Effect of partial ventricular resection in adult <span class="elsevierStyleItalic">Ambystoma mexicanum</span> on ventricle and atrium tension &#40;A&#41; and heart rate &#40;B&#41; on day one &#40;1d&#41; after partial ventricular resection as compared to control&#46; Contractile activity for ventricle and atrium was recorded simultaneously at 16&#177;1&#176;C&#46; &#42; p &#8804; 0&#46;05 when compared to control &#40;C&#41;&#46;</p><p class="elsevierStylePara"><img src="293v80n02-13153399fig3.jpg" alt="Figure 3&#46; Recovery of tension &#40;A&#41; and heart rate &#40;B&#41; values after partial resection of the ventricle of adult Ambystoma mexicanum as compared to control&#46; Contractile activity for ventricle and atrium was recorded simultaneously at 16&#176;C &#177; 1&#46; Both tension and heart rate were lower on days one and five after injury&#46; The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury&#46; AT&#61; atrium tension&#44; VT&#61; ventricular tension&#44; &#42; p &#8804; 0&#46;05 when compared to control&#46;"></img></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Figure 3&#46; </span>Recovery of tension &#40;A&#41; and heart rate &#40;B&#41; values after partial resection of the ventricle of adult <span class="elsevierStyleItalic">Ambystoma mexicanum</span> as compared to control&#46; Contractile activity for ventricle and atrium was recorded simultaneously at 16&#176;C &#177; 1&#46; Both tension and heart rate were lower on days one and five after injury&#46; The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury&#46; AT&#61; atrium tension&#44; VT&#61; ventricular tension&#44; &#42; p &#8804; 0&#46;05 when compared to control&#46;</p><p class="elsevierStylePara"><span class="elsevierStyleBold">Structural evaluation</span></p><p class="elsevierStylePara">Concomitant with the heart contractile activity we corroborated a gradual tissue restoration &#40;<span class="elsevierStyleBold">Figure 4</span>&#41;&#46; One day after damage&#44; the ventricle showed an evident gap that was covered with a cloth &#40;<span class="elsevierStyleBold">Figure 4J</span>&#41;&#59; after 30 days the hole was partially occupied by compact tissue &#40;<span class="elsevierStyleBold">Figures 4C&#44; 4G&#44; 4K</span>&#41;&#44; and 90 days after injury the heart showed a ventricular wall surface and myocardic tissue similar to control &#40;<span class="elsevierStyleBold">Figures 4D&#44; 4H&#44; 4L</span>&#41;&#46;</p><p class="elsevierStylePara"><img src="293v80n02-13153399fig4.jpg" alt="Figure 4&#46; Representative images of the heart of uninjured adult Ambystoma mexicanum control &#40;A&#44; E&#44; I&#41;&#44; and at different times after ventricular partial resection &#40;B&#44; F&#44; J&#59; C&#44; G&#44; K&#59; D&#44; H&#44; L&#41;&#46; Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson&#39;s trichrome&#46; One day after damage&#44; the ventricle showed an evident gap &#40;F&#41; that was covered with a cloth &#40;J&#41;&#59; which is not evident in F because it was removed to photograph&#59; 30 days after injury &#40;G&#44; K&#41; the hole was partially occupied by compact tissue&#44; and 90 days &#40;H&#44; L&#41; after injury the heart showed a ventricular wall surface and myocardial tissue similar to control&#46; A &#61; atrium&#44; c&#46;a &#61; conus arteriosus&#44; V &#61; ventricle&#46; Bar &#61; 1300 mm &#40;A-D&#41; and 1200 mm &#40;E-L&#41;&#46; The arrows indicate the zone of resected tissue one day after injury &#40;F&#44; cloth eliminated&#59; J without elimination of cloth&#41; one days after injury&#44; and recovery tissue at day 30 &#40;G and K&#41; and day 90 &#40;H and L&#41; after damage&#46;"></img></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Figure 4&#46; </span>Representative images of the heart of uninjured adult <span class="elsevierStyleItalic">Ambystoma mexicanum</span> control &#40;A&#44; E&#44; I&#41;&#44; and at different times after ventricular partial resection &#40;B&#44; F&#44; J&#59; C&#44; G&#44; K&#59; D&#44; H&#44; L&#41;&#46; Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson&#39;s trichrome&#46; One day after damage&#44; the ventricle showed an evident gap &#40;F&#41; that was covered with a cloth &#40;J&#41;&#59; which is not evident in F because it was removed to photograph&#59; 30 days after injury &#40;G&#44; K&#41; the hole was partially occupied by compact tissue&#44; and 90 days &#40;H&#44; L&#41; after injury the heart showed a ventricular wall surface and myocardial tissue similar to control&#46; A &#61; atrium&#44; c&#46;a &#61; conus arteriosus&#44; V &#61; ventricle&#46; Bar &#61; 1300 mm &#40;A-D&#41; and 1200 mm &#40;E-L&#41;&#46; The arrows indicate the zone of resected tissue one day after injury &#40;F&#44; cloth eliminated&#59; J without elimination of cloth&#41; one days after injury&#44; and recovery tissue at day 30 &#40;G and K&#41; and day 90 &#40;H and L&#41; after damage&#46;</p><p class="elsevierStylePara">Colocalization of a-sarcomeric actin staining &#40;<span class="elsevierStyleBold">Figures 5A&#44; 5D</span>&#41; and BrdU-labelled-nuclei &#40;<span class="elsevierStyleBold">Figures 5B&#44; 5E</span>&#41; revealed by DAPI staining &#40;<span class="elsevierStyleBold">Figures 5G-5J</span>&#41;&#44; by fluorescence microscopy allowed the identification of BrdU-labelled cardiomyocytes&#46; Five days after injury&#44; the proportion of cardiomyocytes with BrdU-labelled nuclei in the damaged area &#40;<span class="elsevierStyleBold">Figures 5C&#44; 5F</span>&#41; with respect to the total&#44; was 56 &#177; 5&#37;&#46; Ten days after injury&#44; this value corresponded to the 32 &#177; 3&#37; and thirty days after lesion it was the 20 &#177; 2&#37; of the total&#46; In all cases&#44; cell BrdU-labelled nuclei were surrounded by myocardial cytoplasm&#44; as shown in the image reconstructed from 64 optical sections using confocal microscopy &#40;<span class="elsevierStyleBold">Figure 6</span>&#41;&#46; </p><p class="elsevierStylePara"><img src="293v80n02-13153399fig5.jpg" alt="Figure 5&#46; Fluorescence photomicrographs of double immunostaining for a-sarcomeric actin &#40;TRITC&#59; red&#41;&#44; 5-bromo-2&#39;-deoxyuridine &#40;BrdU&#41; &#40;FITC&#59; green&#41; and DAPI &#40;blue&#41; from ventricular myocardium of Ambystoma mexicanum&#46; Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining &#40;A and B&#41;&#44; BrdU-positive nuclei in the same fields &#40;B and E&#41; and merged &#40;C&#44; F&#41;&#46; Images D&#44; E and F correspond to the in-box marked in A&#44; B and C respectively&#46; Panel II shows the co-staining for asarcomeric actin &#40;A&#41;&#44; DAPI &#40;B&#41;&#44; BrdU &#40;C&#41; and merged &#40;D&#41;&#46; Bar &#61; 100 &#181;m &#40;A-C&#41; and 10 &#181;m &#40;D-J&#41;&#46;"></img></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Figure 5&#46; </span>Fluorescence photomicrographs of double immunostaining for a-sarcomeric actin &#40;TRITC&#59; red&#41;&#44; 5-bromo-2&#39;-deoxyuridine &#40;BrdU&#41; &#40;FITC&#59; green&#41; and DAPI &#40;blue&#41; from ventricular myocardium of <span class="elsevierStyleItalic">Ambystoma mexicanum</span>&#46; Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining &#40;A and B&#41;&#44; BrdU-positive nuclei in the same fields &#40;B and E&#41; and merged &#40;C&#44; F&#41;&#46; Images D&#44; E and F correspond to the in-box marked in A&#44; B and C respectively&#46; Panel II shows the co-staining for asarcomeric actin &#40;A&#41;&#44; DAPI &#40;B&#41;&#44; BrdU &#40;C&#41; and merged &#40;D&#41;&#46; Bar &#61; 100 &#181;m &#40;A-C&#41; and 10 &#181;m &#40;D-J&#41;&#46;</p><p class="elsevierStylePara"><img src="293v80n02-13153399fig6.jpg" alt="Figure 6&#46; Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin &#40;TRITC&#59; red&#41; and 5-bromo-2&#39;-deoxyuridine &#40;BrdU&#41; &#40;FITC&#59; green&#41; immunohistochemistry in ventricular myocardium of Ambystoma mexicanum on day five after surgical injury&#46; The image was reconstructed from 64 optical sections by confocal microscopy&#46; In sections from sham-operated animals&#44; cardiomyocytes with BrdU-labelled nuclei were not found&#46; &#40;A&#41; Frontal view of BrdU-labelled nuclei &#40;arrows&#41; in myocardial fibers &#40;&#42;&#41;&#46; View of the myocardial fiber with a rotation of 45&#44; 90 and 180&#186;&#46; In all the cases&#44; nuclei are surrounded by myocardial cytoplasm&#46; Bar &#61; 10 mm&#46; "></img></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Figure 6&#46;</span> Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin &#40;TRITC&#59; red&#41; and 5-bromo-2&#39;-deoxyuridine &#40;BrdU&#41; &#40;FITC&#59; green&#41; immunohistochemistry in ventricular myocardium of <span class="elsevierStyleItalic">Ambystoma mexicanum</span> on day five after surgical injury&#46; The image was reconstructed from 64 optical sections by confocal microscopy&#46; In sections from sham-operated animals&#44; cardiomyocytes with BrdU-labelled nuclei were not found&#46; &#40;A&#41; Frontal view of BrdU-labelled nuclei &#40;arrows&#41; in myocardial fibers &#40;&#42;&#41;&#46; View of the myocardial fiber with a rotation of 45&#44; 90 and 180&#186;&#46; In all the cases&#44; nuclei are surrounded by myocardial cytoplasm&#46; Bar &#61; 10 mm&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Discussion </span></p><p class="elsevierStylePara">Our results represent the first data concerning about the simultaneous evaluation of the structure and function of the heart of adult <span class="elsevierStyleItalic">A&#46; mexicanum</span>&#44; after surgical injury of the ventricular myocardium&#46; We have obtained evidence showing that the structural recovery of myocardium after ventricular injury in the heart of adult axolotl is accompanied by the restoration of its functional capacity&#46; This finding is in agreement with the proposal that adult organisms of early terrestrial animal species are endowed with a higher capacity of tissue regeneration&#46;<span class="elsevierStyleSup">17&#44;18</span></p><p class="elsevierStylePara">Functional assays of the heart of adult <span class="elsevierStyleItalic">A&#46; mexicanum</span> showed a contractile activity with a cyclic pattern of alternating steps of contraction and relaxation&#44; as occurs in the heart of other vertebrates&#46;<span class="elsevierStyleSup">4</span> This pattern was markedly disrupted by the PVA&#46; Besides&#44; the capability to develop tension of both ventricle and atrium was significantly decreased &#40;<span class="elsevierStyleBold">Figures 2 and 3</span>&#41;&#46; </p><p class="elsevierStylePara">The heart rate of 19 &#177; 2 beats&#47;minute&#44; found in control hearts of axolotl&#44; lays within the range of other cardiac rates of other amphibians&#44; which vary from 13 to 23 beats&#47;min&#46;<span class="elsevierStyleSup">19&#44;20</span> In our study the decrease in HR &#40;42 &#177; 6&#37;&#41; in comparison to control &#40;<span class="elsevierStyleBold">Figures 2B and 3B</span>&#41; at one day of injury&#44; was less dramatic than the fall in tension in the ventricle and atrium &#40;84 &#177; 2 and 54 &#177; 4&#37;&#41; &#40;<span class="elsevierStyleBold">Figure 3A</span>&#41;&#46; The force-frequency relationship is an important intrinsic regulatory mechanism of cardiac contractility in which an increase in contractile force is associated with an increase in amplitude&#44;<span class="elsevierStyleSup">21</span> however in failing ventricular myocardium this relation is lost&#46; We suggest that the differences in the proportional changes between tension and HR in our study could be a compensatory response in proportion to the tissue and the force-frequency relationship recovery&#46; This might be related to the hypoxic bradycardia&#44; which occurs in lower vertebrates and which could provide a number of direct benefits to the heart when oxygen supply in the spongy myocardium is precarious&#46;<span class="elsevierStyleSup">22</span></p><p class="elsevierStylePara">One day after the insult&#44; the effect of PVA was reflected as a more evident decrease in VT &#40;84&#37;&#41; and AT &#40;54&#37;&#41; &#40;<span class="elsevierStyleBold">Figures 1b and 2A</span>&#41;&#44; reflecting that the injured structure was the ventricle&#46; Considering that the function of this structure in vertebrates is to develop the necessary pressure to pump blood to other organs&#44;<span class="elsevierStyleSup">1&#44;4</span> its alterations would induce more evident adverse effects&#46; Additionally even when the injury was made in the ventricle&#44; a smaller decrease in the capability of the atrium to develop tension was also observed &#40;<span class="elsevierStyleBold">Figure 3A</span>&#41;&#44; suggesting that the function of other cardiac structures was also altered on the first day as a consequence of the ventricular damage&#46; </p><p class="elsevierStylePara">The progressive reestablishment of the heart rate along with the ventricular- and atrium-tension observed between 30 and 90 days after the PVA&#44; shows that the heart of adult <span class="elsevierStyleItalic">A&#46; mexicanum</span> restore its functional capability when it is impaired by a cardiac damage&#46; Furthermore&#44; as proved later on&#44; this functional restoration is also accompanied by the structural recovery of the heart&#44; which is in accordance with the functional restoration in heart of <span class="elsevierStyleItalic">A&#46; dumerilli</span> after pharmacological heart damage&#46;<span class="elsevierStyleSup">16</span></p><p class="elsevierStylePara">Structural evaluation&#44; based on Masson&#39;s trichrome results &#40;<span class="elsevierStyleBold">Figure 4</span>&#41; together with the colocalization of BrdU-labelled nuclei and a-sarcomeric actin&#44; with the surrounding of the BrdU-labelled nuclei by myocar-dial cytoplasm in the heart of A&#46; <span class="elsevierStyleItalic">mexicanun</span> &#40;<span class="elsevierStyleBold">Figure 6</span>&#41;&#44; shows a notorious recovery of the ventricular tissue and the presence of proliferating cardiomyocyte which were more abundant 5 days after PVA&#46; These results are in accordance with the finding of a subset of cardiomyocytes that progress through mitosis and may enter to successive divisions in the newt&#44; other adult urodele amphibian<span class="elsevierStyleSup">15</span> and with previous reports that detect BrdU<span class="elsevierStyleSup">11</span> and PCNA<span class="elsevierStyleSup">12 </span>in cardiomyocyte of A&#46; <span class="elsevierStyleItalic">mexicanum</span>&#46; Our finding suggests that cardiomyocyte proliferation could be responsible of the structural recovery detected&#46; However&#44; other mechanisms proposed for tissue regeneration&#44; such as the reprogramming of stem cell<span class="elsevierStyleSup">23&#44;24</span> or differentiated cells&#44;25 cannot be ruled out&#46; </p><p class="elsevierStylePara">On the other hand&#44; the reason behind the high regenerative capacity of the heart of adult <span class="elsevierStyleItalic">A&#46; mexicanum</span> is unknown&#59; but it is probably a consequence of the biological characteristics of its cardiac tissue&#46; The heart of adult amphibians consists of spongy&#44; loose and trabecu-late myocardium&#44;<span class="elsevierStyleSup">26&#44;27</span> similar to embryonic myocardium of other vertebrates<span class="elsevierStyleSup">28&#44;29</span>&#46; These characteristics allow the muscle to acquire oxygen by diffusion from luminal blood within the trabecular spaces&#44;<span class="elsevierStyleSup">30</span> which would facilitate the supplement of nutrients and growth factors to cardiac cells&#44; which in turn may result in the production of new cardiomyocyte&#46; However&#44; this remains to be analyzed in future studies&#46; </p><p class="elsevierStylePara">Finally&#44; it is relevant to mention that in our study we demonstrated that the heart of <span class="elsevierStyleItalic">A&#46; mexicanum</span> beats spontaneously <span class="elsevierStyleItalic">in vitro</span> for long periods of time at room temperature&#44; as has been found for other amphibians&#44;<span class="elsevierStyleSup">5&#44;16</span> this allows the evaluation of the contractile activity of cardiac muscle without the necessity of field stimulation&#46;<span class="elsevierStyleSup">6-8</span> Furthermore&#44; the procedure that we used to test functional performance allowed us to register simultaneously the spontaneous activity of both ventricle and atrium&#44; and to assess the intrinsic capacity of the cardiac function independently of the compensatory mechanisms from the rest of the body and avoiding the influence of the anesthetics on cardiac function&#46;<span class="elsevierStyleSup">31 </span></p><p class="elsevierStylePara"><span class="elsevierStyleBold">Conclusions</span></p><p class="elsevierStylePara">We obtained the first quantitative evidence about the recovery of heart contractile activity after PVA in an adult urodele amphibian which indicates that the heart of <span class="elsevierStyleItalic">A&#46; mexicanum</span> restores its functional capacity after PVA in association to cardiomyocyte proliferation&#46; The evaluation of the post-injury changes in the structure and function in the heart of non-mammalian vertebrates&#44; like urodele amphibians&#44; can be very useful&#44; because the proportion of proliferating myocardial cells after damage is very high when compared to mammalian cardiomyocyte&#44; which show a very low ability to proliferate&#46;<span class="elsevierStyleSup">32</span> The possibility of an effective myocardial regeneration in <span class="elsevierStyleItalic">A&#46; mexicanum</span> makes it an interesting model to study the mechanisms underlying heart restoration after an insult&#46; </p><p class="elsevierStylePara"><span class="elsevierStyleBold">Acknowledgements </span></p><p class="elsevierStylePara">We wish to thank Instituto Nacional de Cardiolog&#237;a Ignacio Ch&#225;vez for grant 00-303 to ACM and Centro de Instrumentos Hospital de Especialidades C&#46;M&#46;N Siglo XXI &#40;IMSS&#41; for the Carl Zeiss confocal mycroscope facility&#46; </p><hr></hr><p class="elsevierStylePara"><span class="elsevierStyleItalic">Corresponding author&#58;</span> Agustina Cano Mart&#237;nez Ph&#46;D&#46; Instituto Nacional de Cardiolog&#237;a Ignacio Ch&#225;vez&#44; Departamento de Fisiolog&#237;a&#44; Juan Badiano N&#176;1&#44; Colonia Secci&#243;n XVI&#44; Delegaci&#243;n Tlalpan&#44; CP&#46; 14080&#44; M&#233;xico City&#44; M&#233;xico&#46; Phone&#58; 011 &#40;52&#41; 5573 2911&#44; ext&#46; 1278&#46; <span class="elsevierStyleItalic">E-mail</span>&#58; <a href="mailto&#58;cmamx2002&#64;yahoo&#46;com&#46;mx" class="elsevierStyleCrossRefs">cmamx2002&#64;yahoo&#46;com&#46;mx</a></p><p class="elsevierStylePara">Received in November 15&#44; 2007&#59;<br></br> accepted in March 05&#44; 2010&#46;</p>"
    "pdfFichero" => "293v80n02a13153399pdf001.pdf"
    "tienePdf" => true
    "PalabrasClave" => array:2 [
      "en" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Keywords"
          "identificador" => "xpalclavsec192614"
          "palabras" => array:1 [
            0 => "Amputaci&#243;n parcial del ventr&#237;culo&#59; Coraz&#243;n&#59; Anfibios&#59; Actividad contr&#225;ctil&#59; Axolotl&#59; Ambystoma&#59; M&#233;xico"
          ]
        ]
      ]
      "es" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Palabras clave"
          "identificador" => "xpalclavsec192613"
          "palabras" => array:1 [
            0 => "Partial ventricular amputation&#59; Heart&#44; Amphibian&#59; Contractile activity&#59; Axolotl&#59; Ambystoma&#59; Mexico"
          ]
        ]
      ]
    ]
    "tieneResumen" => true
    "resumen" => array:2 [
      "en" => array:1 [
        "resumen" => "In the present study we evaluated the effect of partial ventricular amputation &#40;PVA&#41; in the heart of the adult urodele amphibian &#40;Ambystoma mexicanum&#41; in vivo on spontaneous heart contractile activity recorded in vitro in association to the structural recovery at one&#44; five&#44; 30 and 90 days after injury&#46; One day after PVA&#44; ventricular-tension &#40;VT&#41; &#40;16 &#177; 3&#37;&#41;&#44; atrium-tension &#40;AT&#41; &#40;46 &#177; 4&#37;&#41; and heart rate &#40;HR&#41; &#40;58 &#177; 10&#37;&#41; resulted lower in comparison to control hearts&#46; On days five&#44; 30 and 90 after damage&#44; values achieved a 61 &#177; 5&#44; 93 &#177; 3&#44; and 98 &#177; 5&#37; &#40;VT&#41;&#44; 60 &#177; 4&#44; 96 &#177; 3 and 99 &#177; 5&#37; &#40;AT&#41; and 74 &#177; 5&#44; 84 &#177; 10 and 95 &#177; 10&#37; &#40;HR&#41; of the control values&#44; respectively&#46; Associated to contractile activity recovery we corroborated a gradual tissue restoration by cardiomyocyte proliferation&#46; Our results represent the first quantitative evidence about the recovery of heart contractile activity after PVA in an adult urodele amphibian&#44; indicating that the heart of A&#46; mexicanum restores its functional capacity concomitantly to the structural recovery of the myocardium by proliferation of cardiomyocytes after PVA&#46; These properties make the heart of A&#46; mexicanum a potential model to study the mechanisms underlying heart regeneration in adult vertebrates in vivo&#46;"
      ]
      "es" => array:1 [
        "resumen" => "En el presente estudio evaluamos el efecto de la amputaci&#243;n parcial del ventr&#237;culo &#40;APV&#41; del coraz&#243;n de un anfibio urodelo adulto &#40;Ambystoma mexicanum&#41; in vivo&#44; sobre la actividad contr&#225;ctil espont&#225;nea del coraz&#243;n registrada in vitro&#44; a diferentes tiempos despu&#233;s de APV&#44; en asociaci&#243;n a su recuperaci&#243;n estructural&#46; Un d&#237;a despu&#233;s del da&#241;o&#44; los valores de tensi&#243;n ventricular &#40;TV&#41; &#40;16 &#177; 3&#37;&#41;&#44; tensi&#243;n auricular &#40;TA&#41; &#40;46 &#43; 4&#37;&#41; y frecuencia cardiaca &#40;FC&#41; &#40;58 &#43; 10&#37;&#41;&#44; resultaron ser menores respecto al control&#46; En los d&#237;as cinco&#44; 30 y 90 despu&#233;s del da&#241;o&#44; los valores alcanzaron 61 &#177; 5&#44; 93 &#177; 3 y 98 &#177; 5&#37; &#40;TV&#41;&#44; 60 &#177; 4&#44; 96 &#177; 3 y 99 &#177; 5&#37; &#40;AT&#41; y 74 &#177; 5&#44; 84 &#177; 10 y 95 &#177; 10&#37; &#40;FC&#41; de los valores control&#44; respectivamente&#46; Adem&#225;s de la recuperaci&#243;n de la actividad contr&#225;ctil&#44; corroboramos la recuperaci&#243;n estructural y gradual del tejido mioc&#225;rdico por proliferaci&#243;n de cardiomiocitos&#46; Nuestros resultados representan la primera evidencia cuantitativa de la recuperaci&#243;n de la actividad contr&#225;ctil del coraz&#243;n de un anfibio urodelo adulto despu&#233;s de APV&#59; indicando que el coraz&#243;n de A&#46; mexicanum recupera su capacidad funcional concomitantemente con la recuperaci&#243;n estructural del miocardio por proliferaci&#243;n de cardiomiocitos&#46; El coraz&#243;n de A&#46; mexicanum es un modelo potencial para el estudio de los mecanismos de la regeneraci&#243;n mioc&#225;rdica de vertebrados adultos in vivo&#46;"
      ]
    ]
    "multimedia" => array:6 [
      0 => array:8 [
        "identificador" => "fig1"
        "etiqueta" => "Figure 1"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig1.jpg"
            "Alto" => 1341
            "Ancho" => 845
            "Tamanyo" => 131723
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Representative traces of spontaneously developed contractile activity of the whole heart of adult Ambystoma mexicanum&#44; in isolated organ assays&#46; Traces correspond to control &#40;a&#41; and to day one &#40;b&#41;&#44; five &#40;c&#41;&#44; and 30 and 90 &#40;d&#41; after partial ventricular resection&#46; Hearts were maintained in amphibian Ringer&#44; pH 7&#46;8&#44; and the contractile activity was simultaneously recorded for ventricle and atrium at 16&#43;1&#176;C&#46; Upper panel shows a complete cycle of contractile activity and criteria of measurement of the ventricular and atrium tensions&#46; A&#61; atrium&#44; V&#61; ventricle&#44; T&#61; tension&#46;"
        ]
      ]
      1 => array:8 [
        "identificador" => "fig2"
        "etiqueta" => "Figure 2"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig2.jpg"
            "Alto" => 845
            "Ancho" => 1854
            "Tamanyo" => 64867
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Effect of partial ventricular resection in adult Ambystoma mexicanum on ventricle and atrium tension &#40;A&#41; and heart rate &#40;B&#41; on day one &#40;1d&#41; after partial ventricular resection as compared to control&#46; Contractile activity for ventricle and atrium was recorded simultaneously at 16&#177;1&#176;C&#46; &#42; p &#8804; 0&#46;05 when compared to control &#40;C&#41;&#46;"
        ]
      ]
      2 => array:8 [
        "identificador" => "fig3"
        "etiqueta" => "Figure 3"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig3.jpg"
            "Alto" => 812
            "Ancho" => 1891
            "Tamanyo" => 89528
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Recovery of tension &#40;A&#41; and heart rate &#40;B&#41; values after partial resection of the ventricle of adult Ambystoma mexicanum as compared to control&#46; Contractile activity for ventricle and atrium was recorded simultaneously at 16&#176;C &#177; 1&#46; Both tension and heart rate were lower on days one and five after injury&#46; The values returned gradually to those observed in control hearts and were similar to control at 30 and 90 days post-injury&#46; AT&#61; atrium tension&#44; VT&#61; ventricular tension&#44; &#42; p &#8804; 0&#46;05 when compared to control&#46;"
        ]
      ]
      3 => array:8 [
        "identificador" => "fig4"
        "etiqueta" => "Figure 4"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig4.jpg"
            "Alto" => 1687
            "Ancho" => 1983
            "Tamanyo" => 690244
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Representative images of the heart of uninjured adult Ambystoma mexicanum control &#40;A&#44; E&#44; I&#41;&#44; and at different times after ventricular partial resection &#40;B&#44; F&#44; J&#59; C&#44; G&#44; K&#59; D&#44; H&#44; L&#41;&#46; Images A-D are photographs of the heart observed on dissection microscopy and images E-L correspond to longitudinal heart sections stained with Masson&#39;s trichrome&#46; One day after damage&#44; the ventricle showed an evident gap &#40;F&#41; that was covered with a cloth &#40;J&#41;&#59; which is not evident in F because it was removed to photograph&#59; 30 days after injury &#40;G&#44; K&#41; the hole was partially occupied by compact tissue&#44; and 90 days &#40;H&#44; L&#41; after injury the heart showed a ventricular wall surface and myocardial tissue similar to control&#46; A &#61; atrium&#44; c&#46;a &#61; conus arteriosus&#44; V &#61; ventricle&#46; Bar &#61; 1300 mm &#40;A-D&#41; and 1200 mm &#40;E-L&#41;&#46; The arrows indicate the zone of resected tissue one day after injury &#40;F&#44; cloth eliminated&#59; J without elimination of cloth&#41; one days after injury&#44; and recovery tissue at day 30 &#40;G and K&#41; and day 90 &#40;H and L&#41; after damage&#46;"
        ]
      ]
      4 => array:8 [
        "identificador" => "fig5"
        "etiqueta" => "Figure 5"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig5.jpg"
            "Alto" => 1679
            "Ancho" => 1991
            "Tamanyo" => 363823
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Fluorescence photomicrographs of double immunostaining for a-sarcomeric actin &#40;TRITC&#59; red&#41;&#44; 5-bromo-2&#39;-deoxyuridine &#40;BrdU&#41; &#40;FITC&#59; green&#41; and DAPI &#40;blue&#41; from ventricular myocardium of Ambystoma mexicanum&#46; Panel I corresponds to representative images at day 5 after ventricular resection for a-sarcomeric actin-positive staining &#40;A and B&#41;&#44; BrdU-positive nuclei in the same fields &#40;B and E&#41; and merged &#40;C&#44; F&#41;&#46; Images D&#44; E and F correspond to the in-box marked in A&#44; B and C respectively&#46; Panel II shows the co-staining for asarcomeric actin &#40;A&#41;&#44; DAPI &#40;B&#41;&#44; BrdU &#40;C&#41; and merged &#40;D&#41;&#46; Bar &#61; 100 &#181;m &#40;A-C&#41; and 10 &#181;m &#40;D-J&#41;&#46;"
        ]
      ]
      5 => array:8 [
        "identificador" => "fig6"
        "etiqueta" => "Figure 6"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "copyright" => "Elsevier Espa&#241;a"
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "293v80n02-13153399fig6.jpg"
            "Alto" => 1512
            "Ancho" => 1520
            "Tamanyo" => 266906
          ]
        ]
        "descripcion" => array:1 [
          "en" => "Three-dimensional reconstruction of confocal analysis for a-sarcomeric actin &#40;TRITC&#59; red&#41; and 5-bromo-2&#39;-deoxyuridine &#40;BrdU&#41; &#40;FITC&#59; green&#41; immunohistochemistry in ventricular myocardium of Ambystoma mexicanum on day five after surgical injury&#46; The image was reconstructed from 64 optical sections by confocal microscopy&#46; In sections from sham-operated animals&#44; cardiomyocytes with BrdU-labelled nuclei were not found&#46; &#40;A&#41; Frontal view of BrdU-labelled nuclei &#40;arrows&#41; in myocardial fibers &#40;&#42;&#41;&#46; View of the myocardial fiber with a rotation of 45&#44; 90 and 180&#186;&#46; In all the cases&#44; nuclei are surrounded by myocardial cytoplasm&#46; Bar &#61; 10 mm&#46;"
        ]
      ]
    ]
    "bibliografia" => array:2 [
      "titulo" => "Bibliography"
      "seccion" => array:1 [
        0 => array:1 [
          "bibliografiaReferencia" => array:32 [
            0 => array:3 [
              "identificador" => "bib1"
              "etiqueta" => "1"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Vertebrates&#46; Comparative anatomy&#44; function&#44; evolution&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Kardong KV&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:2 [
                        "tituloSerie" => "WCB/McGraw-Hill, Boston Massachusetts, pp"
                        "fecha" => "401, 422-470, 1998"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            1 => array:3 [
              "identificador" => "bib2"
              "etiqueta" => "2"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "The cyclo-oxygenase pathway in the avascular heart of the frog&#44; Rana esculenta L&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "Ghiara P"
                            1 => "Parente L"
                            2 => "Piomelli D&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Gen Pharmacol 1984"
                        "volumen" => "15"
                        "paginaInicial" => "300"
                        "paginaFinal" => "313"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            2 => array:3 [
              "identificador" => "bib3"
              "etiqueta" => "3"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Endocardial endothelium in the avascular frog heart&#58; role for diffusion of NO in control of cardiac O2 consumption&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "Adler A"
                            1 => "Huang H"
                            2 => "Wang Z"
                            3 => "et al&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Am J Physiol Heart Circ Physiol 2004"
                        "volumen" => "287"
                        "paginaInicial" => "14"
                        "paginaFinal" => "21"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            3 => array:3 [
              "identificador" => "bib4"
              "etiqueta" => "4"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "The heart&#58; physiology&#44; from cell to circulation&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Opie LH&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:2 [
                        "tituloSerie" => "Lippincott-Raven, Philadelphia, pp"
                        "fecha" => "343-389, 1998"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            4 => array:3 [
              "identificador" => "bib5"
              "etiqueta" => "5"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Pharmacological Experiments on Intact Preparation&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "MacLeod LJ&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:2 [
                        "tituloSerie" => "Churchill Livingstone, Edinburgh, pp"
                        "fecha" => "113, 1970"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            5 => array:3 [
              "identificador" => "bib6"
              "etiqueta" => "6"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Cardiac beta2-adrenoceptor in the frog&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "Stene-Larsen G"
                            1 => "Helle KB&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Comp Biochem Physiol 1978"
                        "volumen" => "60C"
                        "paginaInicial" => "165"
                        "paginaFinal" => "173"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            6 => array:3 [
              "identificador" => "bib7"
              "etiqueta" => "7"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Ericson LE&#44; Poupa O&#46;"
                      "idioma" => "pt"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Carlsten A&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:1 [
                        "tituloSerie" => "The healing of frog heart lesions induced by isoproterenol injections"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            7 => array:3 [
              "identificador" => "bib8"
              "etiqueta" => "8"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Hypoxia and ischemia in buffer-perfused toad hearts&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "McKean T&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "J Exp Biol 1997"
                        "volumen" => "200"
                        "paginaInicial" => "2575"
                        "paginaFinal" => "2581"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            8 => array:3 [
              "identificador" => "bib9"
              "etiqueta" => "9"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Regeneration of ventricular myocardium in amphibians&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "Becker RO"
                            1 => "Chapin S"
                            2 => "Sherry R&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Nature 1974"
                        "volumen" => "248"
                        "paginaInicial" => "145"
                        "paginaFinal" => "147"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            9 => array:3 [
              "identificador" => "bib10"
              "etiqueta" => "10"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Response of the adult newt ventricle to injury&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "Oberpriller JO"
                            1 => "Oberpriller JC&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "J Exp Zool 1974"
                        "volumen" => "187"
                        "paginaInicial" => "249"
                        "paginaFinal" => "260"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            10 => array:3 [
              "identificador" => "bib11"
              "etiqueta" => "11"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Cell cycle reentry of ventricular and atrial cardiomyocytes and cells within the epicardium following amputation of the ventricular apex in the axolotl&#44; Amblystoma mexicanum&#58; confocal microscopic immunofluorescent image analysis of bromodeoxyuridine-labeled nuclei&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Flink IL&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Anat Embryol 2002"
                        "volumen" => "205"
                        "paginaInicial" => "235"
                        "paginaFinal" => "244"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            11 => array:3 [
              "identificador" => "bib12"
              "etiqueta" => "12"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Regeneraci&#243;n mioc&#225;rdica en Ambystoma mexicanum despu&#233;s de lesi&#243;n quir&#250;rgica&#46;"
                      "idioma" => "es"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "Vargas GA"
                            1 => "Prado ZE"
                            2 => "Le&#243;n OM"
                            3 => "et al&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Arch Cardiol Mex 2005"
                        "volumen" => "75"
                        "paginaInicial" => "21"
                        "paginaFinal" => "29"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            12 => array:3 [
              "identificador" => "bib13"
              "etiqueta" => "13"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Heart regeneration in zebrafish&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "Poss KD"
                            1 => "Wilson LG"
                            2 => "Keating MT&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Science 2002"
                        "volumen" => "298"
                        "paginaInicial" => "2188"
                        "paginaFinal" => "2190"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            13 => array:3 [
              "identificador" => "bib14"
              "etiqueta" => "14"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Getting to the heart of regereration in zebrafish&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Poss KD&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Semin"
                        "fecha" => "Cell Dev Biol 2007"
                        "volumen" => "18"
                        "paginaInicial" => "36"
                        "paginaFinal" => "45"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            14 => array:3 [
              "identificador" => "bib15"
              "etiqueta" => "15"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Heterogeneous proliferative potential in regenerative adult newt cardiomyocytes&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "Bettencourt DM"
                            1 => "Mittnacht S"
                            2 => "Brockes JP&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "J Cell Sci 2003"
                        "volumen" => "116"
                        "paginaInicial" => "4001"
                        "paginaFinal" => "4009"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            15 => array:3 [
              "identificador" => "bib16"
              "etiqueta" => "16"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Temperature effect on contractile activity of the Ambystoma dumerilii heart previously treated with isoproterenol&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "Cano MA"
                            1 => "Vargas GA"
                            2 => "Guarner LV&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => null
                  ]
                ]
              ]
            ]
            16 => array:3 [
              "identificador" => "bib17"
              "etiqueta" => "17"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Regeneration through phylogenesis&#58; cellular and molecular basis of regeneration&#46; In&#58; Ferretti P&#46; G&#233;raudie JJ &#40;Eds&#41;&#46; From invertebrates to humans&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "Thouveny Y"
                            1 => "Tassava R&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:2 [
                        "tituloSerie" => "Wiley and Sons, New York, pp"
                        "fecha" => "9-43, 1998"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            17 => array:3 [
              "identificador" => "bib18"
              "etiqueta" => "18"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Regeneration in vertebrates&#46;"
                      "idioma" => "de"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Tsonis P&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:2 [
                        "fecha" => "Dev Biol 2000"
                        "volumen" => "221 273-284"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            18 => array:3 [
              "identificador" => "bib19"
              "etiqueta" => "19"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Autonomic influences on heart rate and blood pressure in the toad&#44; Bufo marinus&#44; at rest and during exercise&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "Wahlqvist I"
                            1 => "Campbell G&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "J Exp Biol 1988"
                        "volumen" => "134"
                        "paginaInicial" => "377"
                        "paginaFinal" => "396"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            19 => array:3 [
              "identificador" => "bib20"
              "etiqueta" => "20"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Resting heart rate of the toad Bufo marinus&#58; a long term study of individual differences and environmental influences&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Dumsday B&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Physiol Zool 1990"
                        "volumen" => "63"
                        "paginaInicial" => "420"
                        "paginaFinal" => "431"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            20 => array:3 [
              "identificador" => "bib21"
              "etiqueta" => "21"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Force-frequency relationship in intact mammalian ventricular myocardium&#58; physiological and pathophysiological relevance&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Edoh M&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Eur J Pharmacol 2004"
                        "volumen" => "500"
                        "paginaInicial" => "73"
                        "paginaFinal" => "86"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            21 => array:3 [
              "identificador" => "bib22"
              "etiqueta" => "22"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Tribute to P&#46; L&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Farrell AP&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Lutz: a message from the heart--why hypoxic bradycardia in fishes?"
                        "fecha" => "J Exp Biol 2007"
                        "volumen" => "210"
                        "paginaInicial" => "1715"
                        "paginaFinal" => "1725"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            22 => array:3 [
              "identificador" => "bib23"
              "etiqueta" => "23"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Nuclear reprogramming&#58; a key to stem cell function in regenerative medicine&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "Pomerantz J"
                            1 => "Blau HM&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Nat Cell Biol 2004"
                        "volumen" => "6"
                        "paginaInicial" => "810"
                        "paginaFinal" => "816"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            23 => array:3 [
              "identificador" => "bib24"
              "etiqueta" => "24"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Re-programming of newt cardiomyocytes is induced by tissue regeneration&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "Laube F"
                            1 => "Heister M"
                            2 => "Scholtz C"
                            3 => "et al&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "J Cell Sci 2006"
                        "volumen" => "199"
                        "paginaInicial" => "4719"
                        "paginaFinal" => "4729"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            24 => array:3 [
              "identificador" => "bib25"
              "etiqueta" => "25"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Plasticity and reprogramming of differentiated cells in amphibian regeneration&#58; partial purification of a serum factor that triggers cell cycle re-entry in differentiated muscle cells&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "Straube WL"
                            1 => "Brockes JP"
                            2 => "Drechsel DN"
                            3 => "et al&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Cloning Stem Cells 2004"
                        "volumen" => "6"
                        "paginaInicial" => "333"
                        "paginaFinal" => "344"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            25 => array:3 [
              "identificador" => "bib26"
              "etiqueta" => "26"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Blood supply of the compact and spongy myocardium of fish&#44; amphibia and reptiles&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Romenskii O&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Arkh Anat Gistol Embriol 1978"
                        "volumen" => "75"
                        "paginaInicial" => "91"
                        "paginaFinal" => "95"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            26 => array:3 [
              "identificador" => "bib27"
              "etiqueta" => "27"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Evolution of the ventricles&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Victor S&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Tex Heart Inst J 1999"
                        "volumen" => "26"
                        "paginaInicial" => "168"
                        "paginaFinal" => "175"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            27 => array:3 [
              "identificador" => "bib28"
              "etiqueta" => "28"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Ventricular trabeculations in the chick embryo heart and their contribution to ventricular and muscular septal development&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Ben-Shachar G&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Circ Res 1985"
                        "volumen" => "57"
                        "paginaInicial" => "759"
                        "paginaFinal" => "766"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            28 => array:3 [
              "identificador" => "bib29"
              "etiqueta" => "29"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Developmental patterning of the myocardium&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "Sedmera D"
                            1 => "Pexieder T"
                            2 => "Vuillemin M"
                            3 => "et al&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "fecha" => "Anat Rec 2000"
                        "volumen" => "258"
                        "paginaInicial" => "319"
                        "paginaFinal" => "337"
                        "itemHostRev" => array:3 [
                          "pii" => "S1462388909000982"
                          "estado" => "S300"
                          "issn" => "14623889"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            29 => array:3 [
              "identificador" => "bib30"
              "etiqueta" => "30"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Resting and maximal heart rates in ectothermic vertebrates&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "Lillywhite HB"
                            1 => "Zippel KC"
                            2 => "Farrell AP&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => null
                  ]
                ]
              ]
            ]
            30 => array:3 [
              "identificador" => "bib31"
              "etiqueta" => "31"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Sympathetic cardiac stimulation in Bufo marinus under MS-222 anesthesia&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Smith DG&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:4 [
                        "fecha" => "Am J Physiol 1974"
                        "volumen" => "226"
                        "paginaInicial" => "367"
                        "paginaFinal" => "370"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            31 => array:3 [
              "identificador" => "bib32"
              "etiqueta" => "32"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:3 [
                      "titulo" => "Cardiomyocyte proliferation&#58; a platform for mammalian cardiac repair&#46;"
                      "idioma" => "en"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "Engel FB&#46;"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "fecha" => "Cell Cycle 2005"
                        "volumen" => "4"
                        "paginaInicial" => "1360"
                        "paginaFinal" => "1363"
                        "itemHostRev" => array:3 [
                          "pii" => "S0959804911004679"
                          "estado" => "S300"
                          "issn" => "09598049"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
          ]
        ]
      ]
    ]
  ]
  "idiomaDefecto" => "en"
  "url" => "/14059940/0000008000000002/v0_201307091127/X1405994010533998/v0_201307091127/en/main.assets"
  "Apartado" => array:4 [
    "identificador" => "14673"
    "tipo" => "SECCION"
    "es" => array:2 [
      "titulo" => "Investigaci&#243;n b&#225;sica"
      "idiomaDefecto" => true
    ]
    "idiomaDefecto" => "es"
  ]
  "PDF" => "https://static.elsevier.es/multimedia/14059940/0000008000000002/v0_201307091127/X1405994010533998/v0_201307091127/en/293v80n02a13153399pdf001.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/"
  "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/X1405994010533998?idApp=UINPBA00004N"
]

Article information

ISSN: 14059940
Original language: English

The statistics are updated each day

Year/Month	Html	Pdf	Total

2024 November	6	0	6
2024 October	94	3	97
2024 September	68	9	77
2024 August	45	9	54
2024 July	58	8	66
2024 June	40	6	46
2024 May	52	3	55
2024 April	71	7	78
2024 March	64	5	69
2024 February	83	5	88
2024 January	115	4	119
2023 December	114	11	125
2023 November	141	15	156
2023 October	154	18	172
2023 September	113	10	123
2023 August	97	11	108
2023 July	102	5	107
2023 June	106	4	110
2023 May	132	10	142
2023 April	110	4	114
2023 March	129	4	133
2023 February	101	4	105
2023 January	110	10	120
2022 December	99	8	107
2022 November	100	10	110
2022 October	94	9	103
2022 September	118	23	141
2022 August	81	14	95
2022 July	44	17	61
2022 June	57	9	66
2022 May	62	15	77
2022 April	76	28	104
2022 March	71	12	83
2022 February	83	10	93
2022 January	81	11	92
2021 December	58	8	66
2021 November	83	15	98
2021 October	69	27	96
2021 September	77	16	93
2021 August	66	9	75
2021 July	73	19	92
2021 June	50	11	61
2021 May	64	10	74
2021 April	148	41	189
2021 March	92	34	126
2021 February	89	33	122
2021 January	46	23	69
2020 December	58	11	69
2020 November	62	15	77
2020 October	56	22	78
2020 September	39	11	50
2020 August	50	10	60
2020 July	27	12	39
2020 June	24	13	37
2020 May	84	6	90
2020 April	109	10	119
2020 March	48	9	57
2020 February	52	4	56
2020 January	70	10	80
2019 December	97	17	114
2019 November	58	17	75
2019 October	29	12	41
2019 September	54	4	58
2019 August	41	8	49
2019 July	49	13	62
2019 June	86	21	107
2019 May	199	55	254
2019 April	110	36	146
2019 March	29	17	46
2019 February	22	14	36
2019 January	15	8	23
2018 December	12	6	18
2018 November	26	15	41
2018 October	50	23	73
2018 September	37	6	43
2018 August	12	7	19
2018 July	18	7	25
2018 June	14	7	21
2018 May	24	6	30
2018 April	14	2	16
2018 March	20	2	22
2018 February	16	5	21
2018 January	20	2	22
2017 December	10	4	14
2017 November	21	3	24
2017 October	20	2	22
2017 September	21	5	26
2017 August	17	3	20
2017 July	27	2	29
2017 June	33	6	39
2017 May	36	3	39
2017 April	19	1	20
2017 March	25	42	67
2017 February	13	3	16
2017 January	14	1	15
2016 December	18	3	21
2016 November	20	4	24
2016 October	22	4	26
2016 September	10	1	11
2016 August	14	1	15
2016 July	15	4	19
2016 June	45	10	55
2016 May	55	25	80
2016 April	38	16	54
2016 March	49	19	68
2016 February	43	17	60
2016 January	40	16	56
2015 December	47	14	61
2015 November	40	10	50
2015 October	43	13	56
2015 September	48	6	54
2015 August	79	4	83
2015 July	60	9	69
2015 June	34	2	36
2015 May	52	6	58
2015 April	33	12	45
2015 March	20	9	29
2015 February	16	1	17
2015 January	27	8	35
2014 December	53	6	59
2014 November	45	1	46
2014 October	53	6	59
2014 September	45	7	52
2014 August	50	3	53
2014 July	34	3	37
2014 June	35	5	40
2014 May	43	3	46
2014 April	31	2	33
2014 March	73	14	87
2014 February	75	9	84
2014 January	51	7	58
2013 December	66	6	72
2013 November	62	10	72
2013 October	74	10	84
2013 September	59	9	68
2013 August	73	8	81
2013 July	77	8	85
2013 June	37	3	40
2013 May	41	6	47
2013 April	32	13	45
2013 March	21	8	29
2013 February	13	5	18
2013 January	17	4	21
2012 December	11	3	14
2012 November	5	4	9
2012 October	2	3	5
2012 September	0	1	1
2010 March	694	0	694

Show all

Indexed in:

Follow us:

Statistics

Indexed in:

Follow us:

Statistics

Subscribe to our newsletter