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Biomedical subjects

M Peterka

Publications and source records attributed to M Peterka.

At least 73 records · Page 4Linked to original sources
PubMed1983

Glucocorticoid receptor-mediated teratogenesis in the chick embryo.

The susceptibility of chick embryos to the teratogenic action of intraamniotically injected hydrocortisone increases by several orders during the first four days of incubation. An attempt was made to correlate this phenomenon with the appearance of specific intracellular binding proteins for glucocorticoids. The binding of [3H] corticosterone to the soluble cytoplasmic proteins of the chick embryo was investigated on days 1.5, 2, 3, and 4 of incubation using a gel filtration method. No evidence of high affinity binding was found in embryos on day 1.5. High affinity binding of [3H] corticosterone to the cytosol proteins was first observed in embryos on day 2, but the binding capacity was four times lower than that found in embryos on days 3 and 4. A correlation was obtained between the increasing sensitivity of the chick embryo to hydrocortisone and the appearance of the intracellular binding protein for glucocorticoids. The causal relationship between these two phenomena is further supported by the finding that administration of a nonteratogenic dose of cortexolone completely prevents the teratogenic "cleft beak" action of hydrocortisone, presumably on the basis of competition for binding sites to the glucocorticoid receptor. These findings are consistent with the hypothesis that the teratogenic action of glucocorticoids is mediated by specific cytoplasmic receptors in the chick embryo.

Animals↗
PubMed1983

Origin of hydrocortisone induced orofacial clefts in the chick embryo.

The growth and fusion of facial processes were studied in White Leghorn chicken embryos treated with hydrocortisone. This treatment results in complete bilateral cleft beak in 80-100% of cases. The frontonasal complex of the experimental embryos exhibited marked hypoplasia prior to cleft manifestation. During the critical period for cleft beak formation, the maximum mitotic activity was concentrated in the medial nasal processes, which thus became vulnerable to the mitosis inhibiting effect of corticoids. Primary hypoplasia of the facial processes was documented as a causative factor of corticoid-induced cleft beak which is analogous to mammalian cleft lip/palate.

Animals↗
PubMed1983

Tooth size in children with cleft lip and palate.

The mesiodistal and buccolingual dimensions of primary and permanent teeth were measured in 246 children with either isolated cleft palate or complete unilateral cleft lip and palate. The primary teeth of males with clefts were reduced in their buccolingual dimension compared to the control, while in females there were reductions in the mesio-distal dimension. There were no remarkable differences in the size of the permanent teeth in males with clefts. Females with clefts had reduced buccolingual dimensions of the permanent teeth, in both jaws.

Child↗
PubMed1980

Cardiotoxicity of drugs detected on chicken embryos.

Results of direct observation of the effects of 9 drugs with known cardiotoxic properties upon the embryonic chick heart after intraamniotic administration on days 4 and 3 respectively, revealed the possibility of rough detection of cardiotoxic properties of newly developed drugs using the rapid, simple and inexpensive technique on chicken embryos.

Animals↗
PubMed1978

Differences in the size of the palatal processes in mouse embryos with cleft palate induced in two critical periods.

Using planimetric measurements of projections of the space between the palatal processes of ICR-Velaz mouse embryos, we indirectly demonstrated that the pre-horizontalization size of the palatal processes after the i.m. administration of 7.5 mg cortsone acetate on the 12th day of gestation was smaller than in the controls. After horizontalization, the inadequate palatal processes were unable to meet in the midline as they do in the majority of normal embryos. The administration of 0.5 mg 6-amino-nicotinamide on the 14th day of gestation did not significantly affect the size of the palatal processes.

6-Aminonicotinamide↗