AIM:To study if low dose NaNO2 can induce the adaptive response of cultured Chinese hamster lung cells(CHL cells)to DNA damage.METHODS:Single cell gel electrophoresis technique was used to detect the DNA damage in CHL cells exposed to NaNO2 at different concentrations.CHL cells were pretreated with NaNO2 of concentrations of 0.01 mg/L,0.1 mg/L and 1 mg/L respectively.And the adaptive response to the toxicity of 1g/L NaNO2 was observed.The activity of polyADP-ribose polymerase(PARP-1) of CHL cells was inhibited with 3-aminobenzamide(3AB) before or after pretreated with low dose of NaNO2.And the changes of the adaptive response were observed.RESULTS:The rate of tailing cells was 7.87% when the cells were exposed to 1 g/L NaNO2 without pretreatment with low dose NaNO2.An extremely remarkable statistics significance(P0.05).The adaptive response could be blocked when the activity of PARP-1 was inhibited with 3AB before the low dose pretreatment,but could not be blocked when the activity of PARP-1 was inhibited after low dose NaNO2 pretreatment 6 h.CONCLUSION:NaNO2 of concentration that equals to or lowers than 0.1 mg/L can induce the adaptive response of cultured CHL cells to DNA damage caused by high dose NaNO2 through PARP-1 activation.And the dose of NaNO2 that can induce adaptive response might not cause the DNA damage.

AIM: To study the significance of expressio n of fms-like tyrosine kinase 4 (Flt-4) in different histopathological grades of a strocytoma. METHODS: The surgical specimens from 50 brain astrocytoma patien ts were stained immunohistochemically for examining Flt-4 and vascular endotheli al growth factor (VEGF) expression. Intratumoral microvessel density (IMVD) was calculated by labeling the endothelial cells of the blood vessels within the tum or. RESULTS: Flt-4, VEGF expression were closely correlated with his topathological grades of astrocytoma. Flt-4 and VEGF expression were found in 52 % (26/50), 60% (30/50) of tumors. A significant correlation was found between Fl t-4 and VEGF expression (P

AIM: To investigate the mutagenicity of cadmium and zinc and the effect of zinc on the mutagenicity of cadmium. METHODS: The frequency of sister chromatid exchange (SCE) induced by cadmium, zinc and the combination of cadmium and zinc were observed in cultured human lymphocytes. RESULTS: Cadmium induced the increase in frequency of SCE in human lymphocytes from the concentration 1?10~(-8) mol/L to 1?10~(-6) mol/L, but zinc had a negative result. Zinc reduced the frequency of SCE induced by cadmium at the concentration from 1?10~(-6) mol/L to 1?10~(-4) mol/L and a relationship between dose and effect was also observed. CONCLUSION: Zinc inhibits the mutagenicity of cadmium in cultured human lymphocytes.

Objectives To assess the prevalence of and risk factors for some sebaceous glands diseases (seborrhoeic dermatitis, acne, seborrhoeic alopecia and rosacea) and their relation to gastrointestinal dysfunction in adolescents. Methods A questionnaire survey was carried out for the epidemiologic information of sebaceous glands diseases from September to October 2001. A total of 4 600 youngsters aged from 12 to 20 years were recruited from 7 middle schools in Macau by random cluster sampling. The statistical software of SPSS 10.0 was used to analyze the data. Results The prevalence of seborrhoeic dermatitis, acne, seborrhoeic alopecia and rosacea was 2.7%, 45.5%, 1.6% and 0.7% respectively. Based on multivariate logistic regression analysis, the risk factors of sebaceous glands diseases included age, gastrointestinal dysfunction, season (summer), spicy and fried food, a family history of acne and the presence of long hairs on areolae of breasts. Gastrointestinal dysfunction was correlated with the incidence rates of seborrhoeic dermatoses (P = 0.007, OR = 1.208, 95% C.I 1.053 ~ 1.385). Conclusion Gastrointestinal dysfunction is an important risk factor for diseases of the sebaceous glands and correlates with the occurrence and development of these diseases.

Objective: To detect the alterations of telomerase activity and the expression for oxidative stress responsive genes related with senescence during cellular replicative senescence and hydrogen peroxide-induced premature senescence in human embryonic lung fibroblasts (HELFs) in vitro. Methods: The HELFs were divided into young cells (22 population doubling levels, 22PDL) , mid-aged cells (35PDL) and replicative senes-cent cells (49PDL) and premature senescent cells induced by H₂O₂(premature senescence, PS). The telomerase activity was detected by ELISA assay during cellular replicative and premature senescence. The mRNA level of oxidative stress responsive genes related with senescence for Foxo1, Foxo3, Pdx1, apoA-I and MMP1 was per-formed by RT-Q-PCR separately. Results: The mRNA level for Foxo1, Foxo3, apoA-I and Pdx1 was decreased separately during cellular replicative senescence compared to that in the young-stage cells with statistical signifi-cance (P<0.05). The expression of MMP1 was up-regulated 5.1-fold obviously (P<0.05). In premature senes-cence, the mRNA level was only decreased for Foxo1, Foxo3 and apoA-I, but up-regulated 2.3-fold and 6.2-fold for Pdx1 and MMP1 respcetively vs 22PDL significantly (P<0.05). The telomerase activity in young cells was not detected, and it increased in mid-aged cells and replicative senescence stages during cellular replicative se-nescence as compared to 22PDL with statistical significance (P<0.05). The telomerase activity in premature se-nescence was highly active. Conclusion The expression for genes related with senescence has differences be-tween replicative and premature senescence and hydrogen peroxide modifies their expression levels. The telomer-ase activity has been going up with increased PDLs.