The mutagenicity of 22 kinds of foods, including soy sauce, fish sauce, shrimp paste, sausages, sundried fishes, rice cracker, deep fried pork skin, salfed vegetable and spices after nitrite treatment, was detected by means of Ames test with preincubation. Mutagenicity assay was employed on salmonella typhimurium TA100, aud meanwhile, the validity of each experiment was checked by using the koown mutagen, AF-2, as the positive control.16 kinds of foods showed marked direct-acting mutagenicity toward Salmonella typhimurium TA100 after nitrite treatment.Shrimp paste produced in Bankok was the strongest one among these samples.Its specific mutgenicity was 37000 revertants/g.The amount of precursor, tyramine, in shrimp paste was estimated from the area of tyramine peak on HPLC by using the authentic tyramine as the standard.Results showed that one gram shrimp paste contained 439ug tyramine.The mutagenicity of foods suggested that nitrosatable precursors, such as amine or amide, were presented in foods, and they could converted into endogenous carcinogen, mtrosamine, in vivo.Therefore, detection of mutagenicity of foods has significance in preventing cancer.

331 silicosis patients have been observed for their forward therapeutic effect in continuation of the treatment with Hydroxypiperaquine. The exact therapeutic effects have shown ar follows :1.The ratio of improving the major symptoms was 46.05-58.2%.2.According to the X-ray photograph, it revealed that 10.29% of patients were improved, 66.54% were stable, and only 14.34% of the disease were in progress. The ratio of progress in cases during five years before or after treatment with Hydroxypiperaquine was 68.85% and 22.95% respectively. It means that two thirds of patientt could been retarded the progress of disease.3.The results from biochemical and immunological indexes have also shown thas the progress of the disease was controlled.None of the serious side effects was found during the continuation of treatment.

We have synthesized Hydroxypiperaquine Phosphate (HPQP) as a new antimalarial drug in 1971. Studies have shown that the drug has markedly therapeutic effects on experimental silicosis after administration to rats 100mg/kg by oral twice per week and the treatment was performed either in the earlier or later course of silicosis. We tried to treat 663 cases for silicosis with HPQP. Patients took cure up to two years. As a result of therapeutic effect examining by X-ray photograph, it revealed that 153 cases of them were marked improved, a few of cases (about 6.49%) were still in progress, and the remainders were stable as before.This study proved that HPQP can alleviate patients' suffering, prevent or retard the progress of the disease. We, there-fore, recommed the drug to be the choice of good therapeutic medicine for silicosis.

0.05).The results showed that HPQP has a protective effect on macrophages.incubated with silica, and we are inclined to think that the effect might serve as a therapuetic basis for treating silicosis by HPQP.

In this experiment, teratogenic effect of Hydroxypiperaquine Phosphate has been studied in mice.We divided the pregnant mice into five groups: (1) normal control' (2) positive control, (the mice were administered 0.3 ml concentrated cod liver oil containing vit A 15)000 IU per day.) (3) the highest dose group of HPQP, (1/3LD50 per mouse per day), (4) medium close group (1/9LD50), (5) lower dose group (1/27 LD50).HPQP was given to the mice on the 9th day to the 14th day of gestation.Dams were killed for the teratological examination on the 18th day.We found that the number of the resorbed and dead fetuses markedly increased in the positive control group.The changes of those fetuses included growth retardation and external abnormalities such as microcephaly, encephalocele.open eyes, small ears, phocomelia, syndactylia, ectrodactyly and gastroschiasis were observed.Besides, the cleft palate and some skeletal alterations such as delayed ossifications of skull bones and dilatant ribs were observed too.We have not found in this experiment any evidences of embryotoxicity in the normal and ail of HPQP groups, The experimental results showed that the drug did not exert teratogenic effect on mice.

0.05) .The dominant lethal test has also suggested that HPQP was a non-mutagen based on the data of percentage of living embryos, average number of early deaths and percentage of females with one or more dead implant.

0.05). However, 0.01 and 0.1 mg/L mercury in water significantly increased the frequency of micronucleated cells in Vicia faba root tips (P

The inhibitory and antimutagenic effects of 17 compounds, cysteine (1), cinnamic acid (2), rutin (3), tannic acid (4), germanium dioxide (5), fluro uracil (6), sodium copper chlorophylline (7), B-sitosterol (8), vitamin C (9), coumarin (10), vitamin E (11), L-glutathione (oxidized form) (12), L-glutathione (reduced form) (13), sodium selenile (14), organic germanium (15), L-methioine (16) and proline (17) on the SOS response induced by N-methyl-N'-nitro-N-nitrosoguanidine, niethly muthanesulfonate, benzo (a)pyrine and UV were studied by using SOS chromotest. The results showed that compounds 1~15 revealed inhibitory effects, and compounds 2~8 and 10-11 revealed antimutagenic effects. It was demonstrated that cinnamic acid is the best antimutagen among 17 compounds. Cinnamic acid has not only inhibitory effect but also antimutagenic activity towards a wide variety of mutagens/carcinogens. The modes, specificity and end point of action of antimutagens are discussed.

In the present paper, antimutagenic mechanisms of hotbed chives, fragrant-flowered garlic and garlic leaves were investigated by the SOS Chromotest The results showed that these vegetables could inhibit the SOS respones induced by temperature (42℃) in E coli GW1060 and GW11M (rec 441 (tif)), but they could not act on SOS network gene expression in E. coli GW2707 (lexA::Tn5), so one of their antimutagenic mechanisms is inhibitory effect on cleavage of lexA by RecA protease. Desmutagenic test results indicate that some aqueous extractions of the three vegatables can inactivate mutagens outside cells.

1 ?mol/L,24 h); (3) With the development of neoplastic transformation, the resistance to terminal differentiation induced by some promoter increased till the promoter became mitogenic. Conclusion: The development of transfected cells provides a powerful and convenient model for detecting potential tumor promoters and research on the mechanisms of promotion tumor.