In Japan, 303 teenagers with thalidomide embryopathy have been registered by the Ministry of Health and Welfare of the Japanese Government. Of 303 patients, the 242 patients showed radial logitudinal reduction malformations in various degrees, thalidomide dysmelia. The authors classified the malformations into the following 5 types; 1) thenar muscle hypoplasia-type, 2) thumb ray hypoplasia- or aplasia-type, 3) radial clubhand-type, 4) phocomelia-type and 5) amelia-type . Thenar muscle hypoplasia-type was observed in 53 limbs; thumb ray hypoplasia- or aplasia-type was observed in 1 59 limbs; radial clubhand-type was observed in 225 limbs; phocomelia-type was observed in 43 limbs; and amelia-type was observed in 4 limbs. The authors believe that this study is worth while not only to know today's nation-wide statistical results of thalidomide dysmelia but also to apply this study to that of morphological sequence of radial longitudinal reduction malformations not caused by thalidomide.

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The statistical association between the incidence of congenital hydrocephaly and paternal age, maternal age and birth order was analyzed in 492 cases of fetal deaths with congenital hydrocephaly reported during 1975-1976. The birth order association was confirmed with a high degree of statistical significance. The quadratic model fitted the data better than the linear one in explaining the variation of incidence of congenital hydrocephaly.

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Congenital megacolon rats were found in offspring of a female albino rat crossed with a wild male. In megacolon rats, their eyes were dark and their coats were almost white with only small pigmented spots on the heads. These rats could not survive more than 35 days after birth because of the fecal stasis. At autopsy of these rats, the upper side of the intestine enlarged and the anal side of that narrowed. Narrow segments of the lower intestine were found in the lower colon, in the total colon or in the lower small intestine and total colon in respective rats. From histological observations, it was confirmed that myenteric ganglion cells of the narrow segment were absent. And it was demonstrated by genealogical analysis that the congenital aganglionosis was controlled by an autosomal recessive gene. We named these megacolon rats Congenital Aganglionosis Rat and this gene Spotting Lethal, sl. It has since been maintained by heterozygous brother-sister matings.

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Pregnant CF#1 mice were exposed to single whole-body X-irradiation at a dose of 25R on day 10, 13 or 15 of pregnancy. The embryos and fetuses were exarnined for early pathological changes of neuroepithelial cells in the telencephalon with light and electron microscopy. The embryos and fetuses irradiated with 100R were also examined. In light microscopy, the earlier the day on which exposure to irradiation took place cells with cytoplasmic inclusion increased earlier and showed a higher incidence. They increased before the start of pyknotic cell increase in the groups irradiated with 25R on day 10 and 13. In electron microscopy, cytoplasmic inclusion observed with light microscopy was divided into cytoplasmic degeneration and phagocytosed necrotic cell. Cytoplasmic degeneration was observed before nuclear changes in day 10 and 13 embryos irradiated with 25R. Cytoplasmic degeneration was not observed in day 15 irradiated fetuses. Phagocytosis of necrotic cells tended to appear later in day 13 irradiated embryos than in day 10 and 1 5 irradiated embryos and fetuses. It was noticed that the first detectable changes in the cells of mouse embryonic brain were cytoplasmic degenerations before nuclear change. The time at which cytoplasmic degeneration and phagocytosis appeared was found to differ according to the stages of gestation irradiated.

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In order to ascertain the role of embryonic facial structure for the manifestation of genetic microphthalmia (mic), excessive vitamin A (VA) was administered to mic mice on day 8-9 of pregnancy, and the embryos and fetuses were examined. In non-treated mic embryos, the maxillary process grew upward and the optic vesicle was blocked from contact with the head ectoderm. In the VA-treated embryos, reduction of the maxillary process was marked and the lens was fairly well induced. The size of the lens and the eyeball of fetuses in the treated group was significantly larger than in the non-treated one. The incidence of histological abnormalities, such as incomplete detachment of the lens, incomplete closure of the embryonic fissure and persistent primary vitreous was reduced by the VA-treatment. These findings indicated that the morphological deviation of the embryonic facial structure played a significant role for the manifestation of the microphthalmia (mic).

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The purpose of the investigation was to clarify the influence of immune response in the mother upon the embryonic development. One ml and two ml of rabbit serum-protein were injected intraperitoneally into mice on day 12 of pregnancy. The administration of heterologous protein resulted in the supression of body weight increase of pregnant mice and also in the decreased number of live fetuses and the increased number of absorbed embryos. The treatment with foreign protein during pregnancy produced malformed fetuses in mice. Dose-response relationship was obvious in the findings. A teratogenic spectrum was confined to cleft palate and limb abnormalities in relation to the timing of treatment. It is of interest to note that the malformations were often accompanied with hematomas in their neighborhoods, i.e. at the snout-tip and the tips of the hand and the foot.

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