In proceeding with the comparative investigations with 5-fluoro-2'-deoxycytidine (F-CdR) in inbred mice we used a strain of random bred golden hamsters maintained for years at our laboratory and tested the embryotoxic and teratogenic dose response relations at stage day IX of pregnancy. It could be stated that the status of differentiation at stage day IX of pregnancy may be externally comparable with day X in the mouse (C57BL/6 and C57BL/10) except for some features. In experimental series attention was focused mainly on the skeletal system, i.e. the skull, the vertebral column and the limbs. Primordia of the vertebral column reacted most, while those of the skull reacted least. Analogous to the earlier investigation with mice we defined types of multiple regional skeletal defects of the three main parts. Animals with defects in all three main parts of the skeleton were the most frequent, whereas the combination of defects of limbs and vertebral column had lower incidence. With in-creasing doses multiple regional defects were increased while single regional defects declined. The types of malformations were described.

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Cyclohexylamine was found as a metabolite of sodium cyclamate in humans and dogs, which had orally received the sweetener (Kojima and Ichibagase, 1966). Since then, toxicity of cyclohexylamine has been studied by many investigators and it was revealed to cause chromosome aberrations in mammalian cells in vivo as well as in vitro (Legator et al., 1969; Stoltz et al., 1970; Tonmura, 1969, 1970). The present experiment was carried out to examine embryotoxic effects cyclohexylamine in mice. Pregnancy of ICR mice was timed by counting the morning on which the vaginal plug was found as day 0. Cyclohexylamine was diluted with distilled water and given orally to the pregnant mice at 100, 50, and 20 mg/kg/day for six days either from day O to day 5 or from day 6 to day 11 of gestation. Fetuses were removed on day 18 of gestation, all implantation sites counted and the living fetuses weighed and examined for external malformation and then for skeletal abnormality following staining with alizarin red S. Cyclohexylamine at 100 mg/kg/day was mildly embryolethal when administered from day 6 to day 11 of gestation. This dosage, however, was also mildly lethal to the adult female mice when administered for 6~10 days. Body weight of the living fetuses was significantly decreased when 100 mg/kg/day of cyclohexylamine was given from day 6 to day 11 of gestation. Such a growthsuppressing effect of the agent was not so evident in other experimental groups. No teratogenic effect of the agent was revealed in any experimental group. As a result, it was concluded that the level of embryotoxicity of cyclohexylamine is about the same as that of its subacute toxicity in the adult female. Discrepancies in the results of teratological examinations of cyclamate (Tanaka, 1964; Nees and Derse, 1967; Fritz and Hess, 1968; Klotzsche, 1969; Lorke, 1969 a, b) were discussed and it is assumed that cyclamate also has no teratological effect on the offspring when administered to pregnant animals.

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母体マウスの年令または体重が,妊娠中に薬物を投与することにより,その胎仔に如何なる障害があるかを副腎皮質ホルモンを用いて調査した.生後4週令より75週令迄の間の未経産ICR-JCL系マウスを妊娠させ,その11日より14日までの関連続4日間,prednisoloneのCMC懸濁液を25mg/kgの割合で背部皮下に注射し,妊娠末期に開腹し胎仔を観察した.なおCMC懸濁液で同様に処理したものを対照例とした.その成績の大要はつぎのようである.1)各年令群における死亡胎仔の頻度を対照例と実験例とで比較したところ52-75週令群では有意の差はなく,他の年令群では実験例で高かった.2)胎仔の死亡率の年令による推移については対照例と実験例は,ほば同様であった.3)実験例における生任中の口蓋裂の発生率は23週令まではほぼ一定でありこれより高年令になるにしたがい減少した.4)各年令群における母獣の体重と口蓋裂の発生率との関係を求めたところ,相関関係はなかった.5)平均生存胎行数と口蓋裂の発生率との関係を各年令群について求めたところ,いずれにおいても両者問の相関関係はみとめられなかった.6)各年令群とも生存胎仔の体重は常に実験例では対照例より優っていた.

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A parasitic body, i. e. the fist-sized trunk with the arms and legs was attached to the epigastric region of a male newborn at full-term birth. The parasite showed spontaneous urination and movement of the extremities, and was detached successfully. The autosite died of cyanosis and dyspnea 7 days after birth. The autosite weighed 2,800g. No external anomalies except for the parasitic body were present. Cardiac anomalies including ventricular septal defect, overriding of the aorta and patency of the foramen ovale were detected. Besides, acute bronchopneumonia and congestion of the liver, kidney and spleen occurred. An artery arising from the right subclavian artery entered into the parasite in the region of the xiphoid process after running down behind the sternum. The blood circulating through the parasite flowed back into the left atrium of the autosite. The parasite weighed 400g. The upper and lower extremities were almost well-developed on both sides. No anomalies of the hands and feet were found. The head, thorax, upper abdomen and vertebral column were defective. In the abdominal cavity there were blind-end isolated small and large intestines with the appendix. No rectum and anus were formed. The uro-genital organs consisting of one fused kidney with the adrenal glands, urinary bladder, two ureters, prostate, penis and two testicles in the scrotum were also found. No anomalous genitals were seen. On x-ray examination, the autosite revealed almost complete formation of the skeleton. In the parasite the bones of the upper and lower extremities and pelvis were clearly shown, but the cranium, vertebrae, sternum and ribs were not indicated. It was pointed out that in the autosite cardiac anomalies were found, and that in the parasite the uro-genital organs as well as the lower portion of the skeleton were relatively well-developed.

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