Purpose: To investigate the effect of Vit. A deficiency on Hox3.5 mRNA expression and development of mouse embryos. Methods: Sixty Kunming female mice were divided in to four groups: normal control group N ( 4 000 IU Vit.A/kg diet),Vit.A deficiency group A ( 0 IU Vit.A/kg diet)、Vit.A-supplement after 0d.p.c (day post coitus), group B and Vit,A-supplement after 7 d.p.c group C (B、C were fed 0 IU Vit.A/kg diet before crossover, B was fed 10 000 IU Vit.A/kg diet after 0 d.p.c and C was fed 10 000 IU Vit.A/kg diet after 7 d.p.c.). On the 12th day p.c. pregnant mice in every group were killed and the uteri were dissected and the mouse embryos were taken out immediately. Meanwhile, blood samples were taken from pregnant mice for the determination of serum Vit.A. In situ hybridization was used to determine Hox-3.5 mRNA expression in the mouse embryos by digitoxin-labeled cDNA probes. Results: Hox-3.5 mRNA expression in the embryos of group A and C decreased significantly as compared with group N and B (P<0.01， P<0.05),and there was no difference between group B and group N. The level of Hox-3.5 mRNA expression in group C was higher than that of group A, but still lower than group N. Vit.A-deficiency(A) was significantly lower than that of group A and abnormal development of the skeleton existed. Moreover, encephalocele and micro kidney were found. Conclusion: Vit.A may regulate Hox gene expression in transcription level and may influence the development and growth of embryos.

Purpose: This study was designed to evaluate the effects of two methods, hormone induction ovulation(HIO) and culture in vitro maturation (CVM), on the quality and chromosomal complements in mouse oocytes. Methods: 100 matured mouse oocytes were obtained by HIO and 80 by CVM. Their chromosomal complements were prepared and analyzed. Results: The hyper haploid rate, aneuploid rate, chromosomal structurally aberration rate, structurally aberrated oocyte rate, degenerative oocyte rate and mean number of splitting chromosomes in HIO group were 2.0 ％,4.0 ％,2.0 ％, 2.0 ％, 8.0 ％ and 0.13 subsequently, and were 4.0 ％, 8.0 ％, 7.5 ％, 6.3 ％, 12.5 ％ and 0.32 5 in CVM group. All the parameters between two groups are not signifi cantly different. Conclusion: The qualities and chromosomal complements of mouse oocytes obtained by CVM were not naturally different from those by HIO. Extrapolating to human, this result suggested that the maturation in vitro of immature oocyte would have great potential for human assisted reproduction.

Purpose: The aim of this study was to observe the anti－oxidative activity of spirulina platensis and to explore anticarciogenic mechanism of spirulina platensis. Methods: Single cell gel electrophoresis (SCGE) assay was used to observe and evaluate the anti－oxidative activity of spirulina platensis. Results: T he results demonstrated that Spirulina platensis could protect CHL cellular DNA from damage induced by hydroxy free radical in dose－dependent manner. Conclusion： The anti－oxidative activity of spirulina platensis might plays an important role in cancer chemoprevention.

Purpose: To investigate the change of magnitude of DNA damage induced by B [a]P(benzo [a]pyrene) in Hep G2 cells after pre-treatment with Aroclor1254. Methods: single-cell gel electrophoresis(SCGE) was performed to assay DNA damages caused by aroclor1254(23, 46, 92 and 184 μmol / L) for 24 h alone treatment and B[a] P for 1 h treatment after 24 h pretreatment with Aroclor1254 in Hep G2 cells.Results:DNA damagesinduced by B[a] P increased 8 ％, 16 ％ and 160 ％ respectively in a dose-response manner after pretreatment of Aroclor1254 at 46, 92 and 184 μmol / L compared to the B[a]P treatment alone. A statistically significant increase of DNA damage caused by B[a]P was observed at the concentration of 184 μmol / L of Aroclor1254 pretreatment(P<0.01). Conclusion: DNA damage induced by B[a]P can be enhanced by Aroclor1254, which may be a result from induction of CYP1A1 by Aroclor1254.

Purpose: To study DNA damages induced by 60 Co γ-radiation and o-phenylenediamine(o-PDA) using comet assay. Methods: The DNA damages induced by 0,2,4,6,8,10,15 Gy 60 Co γ-rays and 0,2,4,6,8 μmol / L o-PDA were measured using comet assay. The dose-respose relationship of the CHL cell tail length and the dose of the two type of mutagen were established with Origin 4 software. Results: The tail length of comet, index of DNA damage in this experiment， increased with the dose of 60 Co γ-ray and concentration of o-PDA, respectively. The dose-respose relationship of the CHL cell tail length(TL)and the dose of 60 Coγ-ray fitted for linear-quadratic model: TL=20.41＋2.42D＋0.38D 2; The dose-response relationships for DNA damage induced by o-PDA fitted for linear-quadratic model: TL=1.90＋1.46C＋0.52C 2. Conclusion: The comet assay is a useful tool for determining the genotoxicity of environmental agents.

Purpose: To investigate cyclooxygenase - 2(COX - 2) protein expression in gastric carcinoma and its relationship with the helicobacter pylori(Hp) infection,supply rationale for chemoprevention of gastric carcinoma. Methods: 35 biopsy specimen from gastric carcinoma,18 from gastric dysplasia and 15 from patients with chronic gastritis were examined for COX-2 protein expression by immunohistochemistry ,and Hp infection condition by urease test, respectively. Results: Positive rates of COX - 2 expression in gastric carcinoma group,gastric dysplasia group and chronic gastritis group were 85.71 ％,72.22 ％ and 6.67 ％,respectively. 35 patients in COX - 2 positive cases were Hp positive. Conclusion: COX-2 protein overexpression may contribute to an early event of gastric cancer development and Hp infection may be one of the mechanisms of COX - 2 overexpression.

Purpose and Methods: The study used micronucleus test in Vicia faba to detect and compare the genotoxicity of water samples collected from Panlong River and Dianchi area in Kunming City. Results: Except the sample from the SongHua Dam( the headwaters of Panlong River), all the water samples signifi cantly inducedmicronuclei in vicia faba (P < 0.001～0.01). The highest micronuc leus freauencies was induced by the sample No.6 which was collected in JinTaiTan Irrigation and Drainage station which takes abundant industrial and municipal waste water effluent. Conclusion: The results imply that the water samples from Panlong River and Dianchi lake contain some polluting component(s) which induced genetic damage.

Purpose: To study the antimutagenic effect and mechanism of water extract of tea and related components; to distinguish between desmutagenic dose effect relationship and bactericidal action; in order to discern their similarities or differences in antimutagenesis against direct mutagen(1- NP) and indirect mutagen(Trp- P- 1). Methods: Desmutagenic assay and modified Ames test with Salmonella typhimurim TA 98 were applied. Results: Both tea extract and polyphenols were desmutagenic active without bactericidal action, EGCG and TF were far better than the others; Tea extract was more powerful in antimutagenicity on indirect mutagen(Trp- P- 1) ＋S 9 than on direct mutagen(1- NP)- S 9(P<0.01). The mixture of tea extract and Trp- P- 1 was not mutagenized(without S 9), but was mutagenized with S 9 pre- incubation, and the mutagenic activity was highly related to tea extract inhibiting rate against 1- NP- S 9(r=- 0.969 4). Conclusion: Tea polyphenols can inhibit the formation of indirect mutagen precursors. As a suppressive agent it can also inhibit direct mutagens. Tea polyphenols can form unstable combinations or unsafe structures as they block some strong oxidative mutagens.

Purpose: To study the oral acute toxicity and mutagenicity of Polyoxometalates α-K8H2[SiW9Ti3O40]•15H2O for clinic application(α-Ti3). Methods: The studies were conducted with acute toxicity test,Ames test,micronuclei test and chromosome aberration test on CHO cell in vitro. Results: ① LD50 in mice was 2 055.36 mg/kg ,it was a low-grade toxicity compound .②The results of Ames test showed no mutagenic effects with the concentration ranged from 31.3 to 500 μg/plate with or without S9 mixture added. ③In micronuclei test,the mice orally received 25,50,125 mg/kg level of α-Ti3,no mutagenic effects were observed,and no significant increase was observed on polychromatophil.④The chromosome aberration ratio of α-Ti3 was no significant discrepancy compared with the control on CHO cells,with the concentration ranged from 40 to 320 μg /ml with or without S 9 mixture added. Conclusion： The toxicity of α-Ti 3 was low and no mutagenicity was observed in the experiment.

Purpose： To observe antagonistic effects of garlic extract(GE)and vitamin E to mutagenicity of condensates of cooking oil fumes(COF). Methods： SCE(sister chromatid exchange) was observed and compared before and after addition of garlic extract or vitamin E in different amounts to the culture of human peripheral blood lymphocytes containing different amounts of COF. Then GE(1:10 000 dilution)and / or vitamin E (5 μl) were added to the culture of human peripheral blood lymphocytes containing COF 10μl to compare the changes in SCE. Results： Garlic extract(1:10 000 dilution) could lower SCE of lymphocytes(P< 0.05); Garlic extract and vitamin E had a very significantly synergistic effect on lowering SCE of lymphocytes treated by COF(P< 0.01). Conclusions： Garlic extract and vitamin E have a synergistic effect to antagonize the mutagenicity of COF; garlic extract alone can also lower SCE of human peripheral blood lymphocytes.

Purpose:To study the effects of Taraxacum mongo(TM) on anti-mutation and cell proliferation. Methods: Mitotic Index(MI), chromosome aberration and micronucleus test in bone marrow lymphocytes of mice were determined. Results: ①The MI of bone marrow lymphocytes in mice were in hibited by CP(P < 0.01),but MI were significantly increased compared with control group after TM oral feeding on mice (P < 0.01). ②The inhibition rates of chromosome aberration were 39.62 ％, 58.49 ％ and 54.72 ％ ,respectively by TM in different concentrations of low, medium and high, furthermore the frequencies of micronucleus(MN) were inhibited by CP(P > 0.05). Conclusion: No mutagenicity was observed on TM .but TM possesses the ability of anti - mutation,and promotes cell proliferation.

Purpose: To compare natural micronucleus frequencies in polychromatic erythrocytes (fMPCE) from normal Kunming mouse chest bone marrow to that from normal NIH strain. Methods: According to Procedures and methods for toxicological assessment on food safety, 30 h micronucleus test was performed, the numbers of micronuclei were scored, and the fMPCE was calculated. Results: The natural fMPCE from the chest bone marrow showed skew distribution, and the media was a good indicator. The natural fMPCE of Kunming mice was 1.0 (0, 4.0) in female, and 2.0 (0, 6.0) in male, and there was a significant difference between different sex (P<0.05). The natural fMPCE of NIH mice was 2.0 (0, 4.0) in female, 2.0 (0, 6.0) in male, and there was no significant difference between different sex. There was no significant difference between Kunming and NIH mice in the natural fMPCE. Conclusion: The natural fMPCE from chest bone marrow of Kunming mice and NIH mice are similar. There is no significant difference between two strains; but a significant difference between different sex in Kunming mice does exist (P<0.05).

Purpose:To compare the cycotoxixity,mutagenncity and mouse acute toxicity between Chromium chloride and Potassium dichromate. Methods: MTT method for determition of CHL Cell IC 50, Salmonella mutagenicity test, and mouse acute toxicity test were used. Results: The CHL cell IC 50 of chromium chloride and potassium dichromate were 33.80 mmol / L and 8.02 μmol / L,respectively; the LD 50 of chromium chloride and potassium dichromate in mouse acute toxicity test were 2 143.3 and 171.0 mg / kg,respectively. Potassium dichromate meet the positive respond standards of Salmonella mutagenicity test whereas chromium chloride showed a negative results. Conclusion: Both the cytotoxicity and mouse acute toxicity of potassium dichromate was larger than chromium chloride. Potassium dichromate was mutagennic to Salomamella strains,but chromium chloride was not.

Purpose:To explore potential mutagenicity of thifensulfuron. Methods: The potential mutagenicity of thifensulfuron was studied by Ames test, micronucleus test of polychromatic erythrocytes in bone marrow and chromosomal aberration test of spermatocytes in mice to provide the data for its safety. Results: No increase in the number of revertant colonies was found in the Ames test in all dosage groups. The results were also negative in the chromosomal aberration test of spermatocytes in mice and in the micronucleus test at doses from 1 000 to 5 000 mg/kg. Conclusion: The mutagenicity of thifensalfuron was not showed in this study.

The mouse lymphoma cell mutation assay (shortened as the mouse lymphoma assay or MLA) is often used as a general genetic toxicological assay abroad in order to evaluate the genotoxicity risk. But MLA isn't much often reported in China. In this paper, the assay method and current protocol of MLA is not discussed and described. The areas discussed for MLA were only be on a typical microwell protocol. The method and procedure described were available and could be handled better according to the discription.