FoxN3 is necessary for the development of the interatrial septum, the ventricular trabeculae and the muscles at the head/trunk interface in the African clawed frog, Xenopus laevis (Lissamphibia: Anura: Pipidae).

BACKGROUND: Fox genes are a large family of transcription factors that play diverse roles in the immune system, metabolism, cancer, cell cycle, and animal development. It has been shown that FoxN3 is indispensable for normal craniofacial development in the mouse and the African clawed frog, Xenopus laevis. Morpholino-mediated knockdown of FoxN3 in X. laevis delays overall development of early tadpole stages and causes eye defects, the absence of some cranial nerve branches, and malformations of the cranial skeleton and some cranial muscles, while the skeleton, nerves and muscles of the trunk are unaffected. RESULTS: We report a delay in heart morphogenesis, the absence of the interatrial septum, and a reduction and compaction of the ventricular trabeculation after knockdown of FoxN3 in X. laevis. Furthermore, we found malformations of the cucullaris and diaphragmatico-branchialis muscles, two head muscles that develop in the head/trunk interface of X. laevis. CONCLUSIONS: FoxN3 is necessary for the development of the interatrial septum and trabeculae in the frog heart, as well as the cranial muscles developing in the head/trunk interface. This gives the first evidence for a dependence on the head myogenic program of the cucullaris muscle in an anuran species.

Prosthetic Valve Escaping During Transcatheter Aortic Valve Implantation.

We performed transapical transcatheter aortic valve implantation on an 87-year-old woman with severe aortic valve stenosis. Because of the narrow left ventricular outflow tract, annular positioning of the prosthetic valve proved challenging. During positioning, the prosthetic valve was accidentally dislodged from the balloon catheter and dropped into the left ventricle. Attempted catheter retrieval was unsuccessful. We therefore converted to open surgery without delay. After aortotomy, to our surprise, the prosthesis could not be found, neither in the left ventricle nor in the ascending aorta. Transesophageal echocardiography failed to reveal the location of the missing prosthesis. Fluoroscopy finally displayed the prosthesis in the descending aorta at the level of the left atrium. We proceeded with aortic and mitral valve replacement and closed the sternum. Under fluoroscopic guidance, the prosthetic valve was secured to the wall of the abdominal aorta in an infrarenal position by dilatation with a balloon catheter. This case shows that we should be alert to septum hypertrophy or a narrow left ventricular outflow tract during transapical aortic valve implantation. In such anatomical situations, we recommend advancing the sheath of the application system directly below the annular plane and positioning the prosthesis from this point.

Comportamento do fluxo pelo forame oval em fetos de mães diabéticas com hipertrofia miocárdica / Bahavior of the foramen ovale flow in fetuses of diabetic mothers and myocardial hypertrophy

Introdução: O forame oval (FO) tem extrema importância na circulação fetal, pois conduz o sangue oxigenado proveniente da placenta diretamente ao átrio esquerdo. Frequentemente fetos de mães diabéticas(FMD) apresentam hipertrofia miocárdica(HM), com alterações na função diastólica ventricular esquerda, podendo acarretar modificações do fluxo pelo FO, com reflexo no índice de pulsatilidade. Objetivo: Testar a hipótese de que o fluxo pelo FO apresenta índice de pulsatilidade maior em FMD com HM do que em fetos sem HM de mães com ou sem diabetes. Métodos: Trata-se de um estudo transversal controlado comparando FMD com HM com FMD sem hipertrofia e fetos controles normais. Pacientes: 16 FMD com HM(grupo I), 36 FMD sem HM(grupo II) e 39 fetos controles normais(grupo III), A ecocardiografia fetal com Doppler foi realizada para obter o índice de pulsatilidade do forame oval(IPFO), através da razão velocidade sistólica-velocidade pré-sistólica/velocidade média. Foram utilizados ANOVA e teste das diferenças mínimas significativas, com alfa crítico de 0,05. Resultados: O IPFO médio foi de 4,07 mais ou menos 1,33 no grupo I, 2,28 mais ou menos 0,58 no grupo II e 2,78 mais ou menos 0,55 no grupo III. Houve diferença estatisticamente significante entre os grupos (p menor 0,001); os valores de IPFO do grupo I foram significativamente maiores dos que o do grupo II e III (p menor 0,001). Os valores do IPFO do grupo II não foram significativamente diferentes em relação ao grupo III (p igual 0,604). Conclusão: Fetos de mães diabéticas com hipertrofia miocárdica têm o índice de pulsatilidade do fluxo do forame oval maior do que os fetos sem hipertrofia miocárdica e fetos controles normais. Sugere-se que sua diferença ocorra por uma complacência diminuída do ventriculo esquerdo secundária à hipertrofia do septo interventricular.

Bulboventricular foramen size in infants with double-inlet left ventricle or tricuspid atresia with transposed great arteries: influence on initial palliative operation and rate of growth.

Bulboventricular foramen obstruction may complicate the management of patients with single left ventricle. Bulboventricular foramen size was measured in 28 neonates and infants greater than 5 months old and followed up for 2 to 5 years in those patients whose only systemic outflow was through the foramen. The bulboventricular foramen was measured in two planes by two-dimensional echocardiography, its area calculated and indexed to body surface area. One patient died before surgical treatment. The mean initial bulboventricular foramen area index was 0.94 cm2/m2 in 12 patients (Group A) in whom the foramen was bypassed as the first procedure in early infancy. The remaining 15 patients underwent other palliative operations but the bulboventricular foramen continued to serve as the systemic outflow tract. There was one surgical death. Six (Group B) of the 14 survivors developed bulboventricular foramen obstruction during follow-up (mean initial bulboventricular foramen area index 1.75 cm2/m2). The remaining eight patients (Group C) did not develop obstruction during follow-up and had an initial bulboventricular foramen larger than that in the other two groups (mean initial bulboventricular foramen area index 3.95 cm2/m2). All patients with an initial bulboventricular foramen area index less than 2 cm2/m2 who did not undergo early bulboventricular foramen bypass developed late obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)