ABSTRACT Bis-diamine induces conotruncal anomalies including persistent truncus arteriosus, tetralogy of Fallot, interruption of the aortic arch, and ventricular septal defect in rat embryos when administered to the mother. Bis-diamine also induces extracardiac malformations including thymic hypoplasia, facial dysmorphism, forelimb anomalies and diaphragmatic hernia. However, the teratogenic mechanisms of this chemical in early developing rat hearts have not been fully established. Chimeric studies in chick and quail embryos demonstrated that the cranial neural crest cells reached the cardiac outflow tract, contributing to aorticopulmonary and truncal septation. Since an ablation of the cranial neural crest also produced the conotruncal anomalies, bis-diamine is proposed to disturb the normal migration of cardiac neural crest cells to the heart. Based on our data concerning cardiac anomalies induced by bis-diamine, we reviewed how the cardiac malformations were morphologically established in early developing rat hearts. Our data showed that 1) cardiovascular anomalies induced by bis-diamine are time- and species or strain- dependent. 2) bis-diamine reduces the number of neural crest cells migrating to participate in the conotruncal septation, 3) bis-diamine induces anomalous coronary arteries, thin ventricular walls and epicardial defects, and 4) some embryos cultured in the medium containing bis-diamine had extra-cardiac abnormalities including abnormal location of the otic placodes and delay in mid brain closure. Conclusively, bis-diamine does not appear to merely affect the cardiac development, but rather disturbs normal development of all the organs contributed to by neural crest cells.
ABSTRACT Using female Chinese hamsters stimulated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG), we investigated the influence of hormonal stimulation upon meiotic segregation in oocytes. In 1,576 oocytes ovulated spontaneously from 197 non-treated mature females, the number (percentage) of hyperhaploid oocytes with more than 12 (12–14) chromosomes was 16 (1.0%). These cells had no extra single chromatids, but all had extra chromosomes. Single chromatids were seen in 7 (0.4%) cells with a haploid chromosome set. On the other hand, a total of 1,329 and 1,198 second meiotic (MII) oocytes from 64 mature females and 61 immature females stimulated with PMSG and hCG, respectively, were subjected to chromosomal analysis. Single chromatids were seen in 34 (2.6%) and 62 (5.2%) of these oocytes, respectively. Since these chromatids were mostly paired and the sister chromatids existed near each other in many cells, they may have separated from some chromosomes of haploid cells. Compared with the non-treated females, the frequency of cells with single chromatids was significantly greater in oocytes from both mature and immature females stimulated with PMSG and hCG. The number (percentage) of hyperhaploid cells from mature and immature PMSG-hCG-stimulated females, respectively, was 15 (1.1%) and 14 (1.2%), which was not significantly greater than that in non-treated females. Most of these cells had extra whole chromosomes but one oocyte from mature females and one from immature females had an extra single chromatid. These findings indicate that such hormonal stimulation induces premature centromere separation in MII oocytes and precocious division at anaphase I, which can be assumed by the presence of MII cells with extra single chromatids. Considering that no or less hyperhaploid MII oocytes with an extra single chromatid were seen in oocytes from spontaneous ovulation and from artificial ovulation on hormonal stimulation, these findings suggest that the major mechanism of malsegregations at first meiotic (MI) division is not a precocious division but rather, errors such as nondisjunction of homologous chromosomes (dyads).
ABSTRACT The dermatoglyphics of the hand of 33 male and 17 female, a total of 50 patients with congenital clubfoot deformity (CFD) were compared with those of 250 male and 250 female, a total 500 control cases. The most remarkable dermatoglyphic findings observed in CFD were the decreased frequency of ulnar loops and the increased frequency of whorls on all fingers, the decreased frequency of ulnar loops on the left long finger and ring finger and the right thumb, long finger and little fingers, the increased frequancy of whorls on the left long finger and the right thumb, long finger, ring finger and little fingers, the decreased frequency of palmar IV loops and the increased frequency of ? loops and t triradii and the decreased frequency of plantar Î and V̂ loops and the increased frequency of the p and p″ triradii on the soles.
ABSTRACT Anencephaly is usually observed without association of severe malformations of other organs. A case of polysplenia, which was experienced in a 20-week-old anencephalic female fetus, was reported. The families of the parents had no history of neural tube defects. There was no consanguinity between the parents. The fetus showed a typical anencephaly with absent cranial vault, exophthalmus, hyperplastic thymus and hypoplastic adrenals. There was an atypical polysplenia consisting of five small spleens, absent gall bladder, short pancreas, small intestinal atresia and Fallot tetralogy. No visceral heterotaxy was observed in bronchi, lungs, liver or stomach. Though no direct association has been recognized between anencephaly and polysplenia, recent progresses in the studies of human fetuses and animal experiments help explain the relationship between anencephaly and heterotaxy syndrome. The mother of the present fetus had no history of hyperthermia, drug take or diabetes mellitus. She also had no infections such as virus and toxoplasma before and during pregnancy. There were no clues that would elucidate the etiology of the present anencephalic fetus with polysplenia. Precise surveillance and records of such cases should be advisable.