RESUMO
The cardiac cycle-related deformations of tubular embryonic hearts were traditionally described as concentric narrowing and widening of a tube of circular cross-section. Using optical coherence tomography (OCT), we have recently shown that, during the cardiac cycle, only the myocardial tube undergoes concentric narrowing and widening while the endocardial tube undergoes eccentric narrowing and widening, having an elliptic cross-section at end-diastole and a slit-shaped cross-section at end-systole. Due to technical limitations, these analyses were confined to early stages of ventricular development (chick embryos, stages 10-13). Using a modified OCT-system, we now document, for the first time, the cyclic changes in cross-sectional shape of beating embryonic ventricles at stages 14 to 17. We show that during these stages (1) a large area of diminished cardiac jelly appears at the outer curvature of the ventricular region associated with formation of endocardial pouches; (2) the ventricular endocardial lumen acquires a bell-shaped cross-section at end-diastole and becomes compressed like a fireplace bellows during systole; (3) the contracting portions of the embryonic ventricles display stretching along its baso-apical axis at end-systole. The functional significance of our data is discussed with respect to early cardiac pumping function.
Assuntos
Ventrículos do Coração/embriologia , Coração/diagnóstico por imagem , Coração/embriologia , Imageamento Tridimensional/métodos , Contração Miocárdica/fisiologia , Anatomia Transversal/métodos , Animais , Embrião de Galinha , Fase de Clivagem do Zigoto/diagnóstico por imagem , Coração/fisiologia , Ventrículos do Coração/anatomia & histologia , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/ultraestrutura , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Imageamento Tridimensional/instrumentação , Modelos Biológicos , Tamanho do Órgão , Periodicidade , RadiografiaRESUMO
This paper describes ten children with a developmental defect in the midportion of the odontoid process that may be related to congenital os odontoideum. Six of the patients had a skeletal dysplasia, the seventh had an associated congenital C5-C6 fusion, and the last three patients had no other congenital anomalies.