Healthy adult male animals (48 guinea pigs and 8 rats), showing allert responsesto hearing and equilibrium tests, were selected for chronic and acute experiments respec-tively. Twenty-five guinea pigs received intramuscular injections of streptomycin sulfatedaily in different doses (100 mg/kg in water, 200 mg/kg in water, or 400 mg/kg in 5%calcium gluconate). The rest 23 guinea pigs received same amount of water or calciumgluconate for control. Four rats received a single injection of streptomycin sulfate (600mg/kg in water) and the other 4 controls received water instead. Guinea pigs, admitting 100 mg/kg of streptomycin sulfate daily for one month, showedno conspicuous changes in both functional tests and histochemical examinations. Animals,receiving a daily dose of 200mg/kg or 400 mg/kg with Ca, for two months, lost equili-brium response and became dull in hearing. But these intoxicative effects were observedas early as 58 days and as late as 158 days in individual cases. Histochemical examinations of the pons and medulla oblongalta showed that, in theintoxicated guinea pigs from the chronic experiments, the chromophobe (Ⅲ-type) cellsincreased in number in the terminal nucleus of the cochlear nerve, the lateral terminalnucleus of the vestibular nerve and the primary nucleus of the trigeminal nerse. In thesenuclei, the histochemical reactions of SH-groups, protein-bound histidine, tyrosine and try-ptophan, PAS and succinic dehydrogenase showed a general fall in intensity, while thoseof allcaline and acid phosphatases had no obvious changes. The acetylcholinesterase of the end plates in the intercostal muscle of the rats into-xicated with a single heavy dose of streptomycin sulfate decreased in activity, while thosefrom the chronic experiments did not show any change. Calcium gluconate exhibited the detoxication effect in acute experiments and couldincrease the tolerance dosage in the animals. The author concluded from the experimental facts that streptomycin has a generaltoxic effect on the entire nervous system and discussed the results with the current lite-rature.

The method of combining culture of embryonic chicken mesonephrons or heart fragments with some cells on double layer agar-agar medium is used in this experiment. The authors have investigated with this method invading capacity of malignant esophageal cancer cell line (ECa-109), malignant hepatoma cell line (BEL-7402) and normal diploid Chinese hamster ovary cell line (CHO) to embryonic chicken mesonephrons and heart fragments.The authors have found that both ECa-109 cell line and BEL-7402 cell line have invasive capacity in vitro. The invasive capacity of ECa-109 cells is higher than that of BEL-7402 cells. The normal diploid CHO cells can not invade target organs and show only slight adhesion to them. The capacity for ECa-109 cells or BEL-7402 cells to invade both the embryonic chicken mesonephrons and heart fragment is similar.

40 human fetuses were used in this study. The range of fetal age varied from 3 months to full terms. All fetuses used were normal and their parents were healthy. The CFU-C from bone marrow, liver, spleen and peripheral blood were studied in vitro with agar culture technique modified by Metcalf.Experiments proved that the CFU-C of bone marrow may be observed in the fetuses in 3rd month, however, it increased rapidly in 4th month and maintained higher level until the end of fetal life. The progenitor cell population was detected at very high level in liver from 4th month to 6th month fetuses. The number of CFU-C of fetal liver were low in 7—10th month. The circulating progenitor cells in peripheral blood of 4, 5 and 6-month fetuses Were on high level but it was lower than that of liver and bone marrow.

The tadpole extract without large molecular protein(T-871) was prepared from dry tadpoles. This extract and RPMI1640 medium were mixed in the ratio of 1:50(V/V) to form T-871 medium. HeLa cells were cultured in the T-871 medium in order to study the possible mechanism of HeLa cell differentiation induced by tadpole extract. We found that there was a decreased acitivity of LDH which may be released through HeLa cell membrane in the 2 day's cultured T-871 medium. After 3 day's culture in the T-871 medium we found that on the HeLa cell membranes, Na-K-ATPase activity reduced and the content of Con A receptors increased. When these cells were analyzed by flow cytometry(FACS-420), the results indicated that HeLa cells accumulated in G_2 and M phases of the cell cycle and the influence on DNA and RNA content of the HeLa cells was insignificant. HeLa cells cultured by RPMI 1640 medium or T-871 medium for 3 days were inoculated into the dorsal hypodermis of 12 nude mice, respectively. Then after 24 hours this extract was injected to each nude mouse at dose of 0.3 ml each day. Our study showed that T-871 could result in decrease of tumor formation such as delay of tumor nodule appearance and reduce of tumor weight. This study suggested that the changes of the cell membrane may be caused by the tadpole extract. It may also reduce malignancy of the HeLa cells.