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Biomedical subjects

C Vermeij-Keers

Publications and source records attributed to C Vermeij-Keers.

5 recordsLinked to original sources
PubMed1991

Aplasia of semilunar valve leaflets: two case reports and developmental aspects.

Two fetuses of approximately 11 weeks development with aplasia of the pulmonary as well as the aortic valve leaflets are reported. Both cases showed additional cardiac malformations. Case 1, with all leaflets missing, also had double-outlet right ventricle, hypoplastic left ventricle, large ventricular septal defect, straddling tricuspid valve, and atretic mitral valve. Case 2, with only one hypoplastic aortic valve leaflet, showed hypoplasia of the mitral valve and the left ventricle, and a subaortic ventricular septal defect. The observations made and data in the literature suggest that aplasia of semilunar valve leaflets reflects an underdevelopment of the endocardial cushion swellings at the ventriculoarterial junction, rather than resulting primarily from a malseptation of the cardiac outflow tract.

Adult↗
PubMed1991

Abdominal wall defect associated with persistent cloaca. The embryologic clues in autopsy.

Three stillborn fetuses are reported in which an abdominal wall defect was associated with defects in the urogenital and anal region. Autopsy of these fetuses provided clues indicative of how and where the embryonic development went wrong. The malformation involved a disturbance of the cell deposition process, occurring in the caudal part of the embryo. During the cell deposition process, which takes place in the neural crest and the body wall placode, ectodermal cells are added to the mesodermal compartment of the embryo, thus contributing to the anlagen of several structures, including the ventral body wall. In addition, a change in the shape of the embryo is generated. The sequence of events resulting from a disturbance of the cell deposition process is explained.

Abdominal Muscles↗
PubMed1991

Teratogenic effects of transplacental transfusion of heterologous antisera simulated in an experimental model using in vitro whole rat embryo culture.

The effects of the transplacental transfusion of heterologous rabbit-anti-rat antiserum (RAR antiserum) and subsequent immunological interaction on the development of 9-10 days old rat embryos (stages 8-10 somites) were studied using an in vitro whole rat embryo culture. Transplacental transfusion was simulated by the embryonic intracardiac microinjection of approximately 0.5 microliter RAR antiserum, followed by an incubation period of 24 and 48 hours. All the tested embryos survived the incubation period. Embryos taken from the incubator after 24 hours showed signs of growth retardation and axial non-rotation, a delayed closure of the neural tube and ear vesicle, and a delayed formation of the foregut. They also had a moderate number of areas with local pathogenetic cell degeneration. Embryos taken from the incubator after 48 hours demonstrated signs of growth retardation and incomplete axial rotation. The formation of the foregut and closure of the neural tube was complete, with the exception of one embryo with a persisting open neuroporus posterior. All embryos displayed a considerable number of areas with local pathogenetic cell degeneration. The intracardiac injection technique is an elegant method to test the effects of teratogens administered directly into the embryonic circulation. The results demonstrate that heterologous antisera have teratogenic potential, believed to be due to an immunological reaction, with a particular sensitivity of the neurectoderm in 9-10 day old embryos.

Abnormalities, Drug-Induced↗