Purpose : To study the effect of radiation on the expression of human DNA repair gene hR24L. Methods : We amplified it s open reading f rame f rom human breast cancer MCF7 cells by RT2PCR , and had its sequence checked , irradiated the cells with gamma2ray at a total dose of 5 Gy followed by incubating the cells for different time , collecting cells , isolating the total RNA , analysed hR24L2mRNA by Northern bloting. results :The expression of hR24L2mRNA began to increase at about one hour after irradiation and reached the maximum at about two hours after irradiation. Conclusion : The expression of hR24L gene is damage2inducible , this expression can repair the damage caused by gamma2ray irradiation.

Purpose : Two kinds of antagonist s to cholinergic receptors , at ropine sulfate and d2tubocurarine , were analyzed for their effect s on porcine tubulin polymerization. Methods : Two chemicals were added into the tubulin polymerization/ depolymerization system and the changes of absorption values at value decreased significantly at the reaction solution. The results indicated that 350 nm and 37 ℃were recorded. Results : The chemicals made the absorption value decreased significantly at the reaction solution. The result s indicated that the chemicals st rongly inhibit the polymerization of tubulin. Conclusion : The tested chemicals interrupt the mitosis by tubulin polymerization and may induce aneuploidy by the pathway.

Purpose : To explore the time-course effect s in detecting DNA crosslinks with comet assay and to prove the feasibility of comet assay for detecting DNA crosslinks. Method : Hydrogen peroxide (H2O2) was used as standard DNA breaking agent , the relationship of time2effect s of DNA crosslinks in TK6 cells induced by formaldehyde (FA) was studied using comet assay. Meanwile , two kinds of DNA crosslinking agent s ( FA and mitomycine c) were tested and verified. Results : The length of DNA migration caused by H2O2 decreased with the increase in the dosage of FA and MMC within the doses given. The investigation of time2course effects of DNA crosslinks showed that the action of DNA crosslinks increased with increase in the exposure time of FA.Conclusion : The comet assay could detect both DNA2protein crosslinks and DNA2DNA crosslinks. The cometassay was more sensitive for detecting DNA2protein crosslinks than detecting DNA2DNA crosslinks.

Purpose : To study the influence on the tumorigenicity of the human renal cell carcinoma (RCC) cells by t ransfection of human TNFαgene. Methods : hTNFαcDNA was inserted into ret roviral vector to const ruct recombinant vector pL ( TNFα) SN. The packaged and confirmed ret rovirus were infected to RCC cell line.Then , nude mice were injected by 78620 cell infected with the hTNFαgene or not , and the tumorigenecity of RCC was observed. Results : The mean expression level of TNFαin the supernatant of TNFα2t ransfected 78620 cell2culture medium was (5 004 ±624) pg/ ml. And the nude mice injected with TNFα gene engineered RCC cells had no tumor growth. Conclusion : The TNFαgene engineered human RCC cells lost tumorigenicity.

To probe into the embryotoxicity , the teratogenic effect of sodium selenite as well as it teratogenic dosage and characteristics were studied. Methods : The body weight , body length and tail length of fetuses were measured , the death rate of fetuses and the rate of absorbed embryos were counted , the external appearances and internal organ malformations were observed , ossificated gradation of supraoccipital bone , ossification centers in caudal , forelimb and hindlimb , as well as degree of ossification agenesis in sternebrae were graded and counted. Statistics analysis was made with analysis of variance , chi2square and rank2sum test .Results : The low dosage (0. 6 mg/ kg·bw) was ineffective. In middle (3 mg/ kg·bw) and high (15 mg/ kg·bw) dosage groups , there were agenesia of supraoccipital bone , sternebrae , forelimb and hindlimb in fetuses and the differences were significant ( P < 0. 05～0. 005) comparing the two groups with the cont rol group. Conclusion Sodium selenite possesses embryotoxicity , it s toxicity dosage for mice is 3 mg/ kg·bw and above ; it causes only mouse embryo or fetus ossification agenesis and development retardation.

Purpose and Methods : The mutagenicity of heavyweight aromatic hydrocarbon (HAH) was studied by Ames test , micronucleus test and sperm deformity test in mice , sister chromatid exchange test in human beings. Results : Ames test was negative in all dosage groups. The f requencies of bone marrow micronucleus were increased significantly at the dose of 316～1 580 mg/ kg·bw. The result of SCE showed that the f requencies of SCE in two groups (0. 5 mg/ ml and 5. 0 mg/ ml) were significantly increased. In mouse spermatic deformity test , the rate of spermatic deformity was statistically higher at 1 580 mg/ kg·bw than that of negative group.Conclusion : HAH has potential mutagenicity for somatic cells in mice and human being , and for sperm in mice.We should pay attention to it s occupational exposure and it s application.

Purpose and Methods : To establish a hepatocellular carcinoma (HCC) cell st rain that expresses bcl2-protein stably the ret rovirus expression vector pDOR2SB containing human bcl-2 cDNA was t ransduced into bcl-2 protein negative cell line HCC-9204 by lipid2mediated gene t ransfection method. The bcl-2 t ransfected cells were obtained after being selected with G-418 , and the expression of bcl-2 was detected by immunocytochemist ry after the cells being expanded. The t ransfected cells were cloned by a limited dilution method , and bcl-2 expression in the monoclonal cells was detected with flow cytometer. Results : Bcl-2 protein was expressed in most of the HCC-9204 cells t ransfected with pDOR2SB , but was negative in the HCC-9204 cells t ransfected with pDOR vector and nont ransfected HCC29204 cells. After being cloned for 3 times continually , the monoclonal cell strain that expressed bcl-2 protein at a 100 % positive rate was obtained. Conclusion : The HCC cell st rain that expressed bcl-2 protein stably , was established successfully by gene t ransfection method.

Purpose and Methods : In order to investigate the p16 gene expression and it s relationship with pathological type and clinical stage , 52 Wilms tumor specimens and 7 normal renal tissues aroud tumor were stained routinely by SP immunohistochemical method. Results : Positive expression rate of p16 gene was 30. 8 % 16/ 52) in tumor specimens and significantly lower than that in cont rol 100 % (7/ 7) ( P < 0. 05) . The positiverates were 37. 2 % (16/ 43) , 0 % (0/ 9) in the favorable pathological type and the unfavorable pathological type ,and 47. 6 % (10/ 21) , 37. 5 % (3/ 8) , 28. 6 % (2/ 7) ,6. 3 % (1/ 16) in Ⅰ, Ⅱ, Ⅲ, Ⅳclinical stage respectively. Conclusion : The positive expression of p16 gene was correlated with pathological type and clinical stage , and p16 inactivation seems to be the later event of Wilms tumor progression.

Purpose and Methods : The mutagenecity of two batches of chlorine dioxide (ClO2) were studide using-micronucleus test in V icia f aba root tip cells. Results : The f requencies of micronucleus of two kinds of ClO2 were (17. 91 ±4. 80) ‰ and (17. 5 ±3. 12) ‰ respectively when the diluent multiple of ClO2 was at 1 : 100.=Comparing with the tap water group , the differences (χ2A = 30. 57 , χ2B-= 29. 60 P < 0. 01) was statistically significant and the dose2effect relationship ws clear. Conclusion : Clorine dioxide has mutagenicity. We should pay attention to safety of it s apllication in food and water.

Purpose and Methods : To test the pollution of Sushui River in Wenxi County and the wells along the river using the root tip cells micronucleus test of V icia f aba and garlic. Results : V icia f aba test showed that e water samples taken f rom five places in the River were polluted by genotoxicant s , the order of the pollution severity in turn being Dongqiao , Luzhuang reservoir , Diantou , Suncun and Sucun. The garlic test showed thesimilar result s and a high positive correlation compared with the result s of V icia f aba ( r = 0. 9503 , P < 0. 01)As for the well water , V icia f aba test showed that four out of the five wells near the bank. and two of the five wells distant f rom the bank were polluted. The result s of garlic test indicated that two wells near the bank and one well distant f rom the bank were polluted ; which also showed a positive correlation with the result s of Vicia f aba test ( r = 0. 8790 , P < 0. 025 ) . Conclusion : this study suggested that the river and some of the wells along the river were polluted in a different degree ; garlic as a new method could be used in the study of genotoxity Key words : Pollution of Sushui River ; Wells along the river , Genotoxicity , Micronucleis test .

Purpose and Methods : Allele2specific PCR (AS2PCR) was modfied to identify the genotype of N-acetylt ransferase (NAT2) . Three mutations at the NAT2 gene locus , namely , 481 T , 590 A , 857 A were analyzed. We used the method to investigate the f requency of various genotypes of NAT2 in 76 unrelated Nanjing persons , and the method was tested also. Results : In the population the gene f requencies of Wt , 481 T , 590 A ,and 857 A were 0. 5723 , 0. 0395 , 0. 2368 , 0. 1513 , respectively. The f requencies for NAT2 mutations were significantly different f rom those of Whites , and were similar to those of Asian populations reported. Conclusion : The prevalence of the genotype associated with rapid acetylation among Nanjing people was 82. 9 % , and was proved that the modified AS2PCR is useful in acetylator polymorphism studies.

Purpose : To study sarin toxicity effect on human chromosomes. Methods : Frequency of sister2chromatid exchanges (SCEs) was measured in lymphocytes of 8 victims of Tokyo sarin t ragedy and 49 cont rols and statistical analysis was employed. Results : The mean f requency of exposure group was (4. 916 ±1. 480) / cell.The slightly significant difference was found as compared with the mean f requency (3. 766 ±0. 620) / cell of cont rol (Cochran t test , one tail , P < 0. 05) . Conclusion : The positive result may probably be due to an excess of at ropine (a possible teratogenicity) during emergency t reatment of by three victims with severe symptoms. Proportion was 1∶95 , 1∶25 between dose accumulated of at ropine and dose estimated of sarin. A finally conclusion requires logical and authentic experiment s and more long-term epidemiological investigation. In the t reatment of organophosphorus pesticide poisoning , a compound and altrnate application of special alexipharmic and cholinesterase reactivating agent must be emphasized in order to reduce the possible side effect s of drugs as much as possible.