Document Detail

Anatomy and formation of congenital bicuspid and quadricuspid pulmonary valves in Syrian hamsters.
MedLine Citation:
PMID:  9458068     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Congenital bicuspid and quadricuspid pulmonary valves have received little attention because of their limited clinical relevance. However, knowledge of the mechanisms by which these anomalous valves develop is essential to obtain a more accurate survey of the etiological factors implicated in the malformations of the cardiac outflow tract in mammals. The present study was designed to assess the anatomical features of bicuspid and quadricuspid pulmonary valves in Syrian hamsters as well as to elucidate the mechanisms involved in the formation of these defective valves. METHODS: The sample examined consisted of 206 adults and 28 embryos belonging to a laboratory-inbred family of Syrian hamsters with a high incidence of congenital anomalies of the pulmonary and aortic valves. The study was carried out using histological techniques for light microscopy, semithin sections, and scanning electron microscopy. RESULTS: The pulmonary valve was tricuspid in 140 of the 206 adult hamsters, and in 124 of these tricuspid valves the dorsal commissure was more or less extensively fused. Another 45 hamsters possessed a bicuspid pulmonary valve with the sinuses oriented ventrodorsally. In 43 of these bicuspid valves, a raphe was located in the dorsal pulmonary sinus. The pulmonary valve was quadricuspid in a further nine specimens. The remaining 12 hamsters had a tricuspid pulmonary valve with a raphe-like ridge located in the right pulmonary sinus. In seven of these valves, the dorsal commissure showed a more or less extensive fusion. The embryos examined, aged between 11 days, 3 hours and 12 days, 6 hours postcoitum, were at the beginning of the valvulogenesis. In five of the 28 embryos, the pulmonary valve consisted of three mesenchymal valve cushions, right, left, and dorsal. In a further 17 embryos, the right and left valve cushions were more or less fused toward the lumen of the pulmonary artery. In the remaining six embryos, the left and dorsal valve cushions were normal, whereas the right cushion was divided into two lobes. CONCLUSIONS: The present findings suggest that in the Syrian hamster: (1) bicuspid pulmonary valves result from the extensive fusion of the right and left pulmonary valve cushions at the beginning of the valvulogenesis, (2) the partial fusion of the right and left pulmonary valve cushions leads to the formation of tricuspid pulmonary valves with a more or less extensive fusion of the dorsal commissure, (3) quadricuspid pulmonary valves result from the partition of one of the three valve cushions at a very early stage of the valvulogenesis, and (4) the partial division of the right pulmonary valve cushion may lead to the development of tricupsid pulmonary valves with a raphe-like ridge located in the right pulmonary sinus. In addition, the present findings, together with previous observations in Syrian hamsters, indicate that in this species the mechanisms by which bicuspid and quadricuspid pulmonary valves develop are similar to those by which bicuspid and quadricuspid aortic valves form, respectively. However, the primary factor or factors that induce the malformations of the pulmonary valve operate independently from those inducing the malformations of the aortic valve.
B Fernández; M C Fernández; A C Durán; D López; A Martire; V Sans-Coma
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Anatomical record     Volume:  250     ISSN:  0003-276X     ISO Abbreviation:  Anat. Rec.     Publication Date:  1998 Jan 
Date Detail:
Created Date:  1998-03-05     Completed Date:  1998-03-05     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370540     Medline TA:  Anat Rec     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  70-9     Citation Subset:  IM    
Department of Animal Biology, Faculty of Science, University of Málaga, Spain.
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MeSH Terms
Animals, Inbred Strains / abnormalities*
Aortic Valve / embryology
Embryo, Mammalian / abnormalities
Heart Valve Diseases / congenital,  embryology
Mesocricetus / abnormalities*
Pulmonary Valve / abnormalities*,  ultrastructure

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