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This study intends to assess the potential health hazards of drinking water quality and explore the application of geographic information system( GIS) in drinking water safety in Tianjin. Eight hundred and fifty water samples from 401 sampling points in Tianjin were measured according to the national drinking water standards. The risk assessment was conducted using the environmental health risk assessment model recommended by US EAP, and GIS was combined to explore the information visualization and risk factors simultaneously. The results showed that the health risks of carcinogens, non-carcinogens were 3.83 x 10⁻⁵, 5.62 x 10⁻⁹ and 3.83 x 10⁻⁵ for total health risk respectively. The rank of health risk was carcinogen > non-carcinogen. The rank of carcinogens health risk was urban > new area > rural area, chromium (VI) > cadmium > arsenic > trichlormethane > carbon tetrachloride. The rank of non-carcinogens health risk was rural area > new area > urban, fluoride > cyanide > lead > nitrate. The total health risk level of drinking water in Tianjin was lower than that of ICRP recommended level (5.0 x 10⁻⁵), while was between US EPA recommended level (1.0 x 10⁻⁴-1.0 x 10⁻⁶). It was at an acceptable level and would not cause obvious health hazards. The main health risks of drinking water came from carcinogens. More attentions should be paid to chromium (VI) for carcinogens and fluoride for non-carcinogens. GIS can accomplish information visualization of drinking water risk assessment and further explore of risk factors.

Background & Objective: Previous studies have showed that chromosome 7q occurs a high frequency of loss of heterozygosity (LOH) in primary gastric carcinoma; D7S486 located in 7q31 is a locus with the highest frequency of LOH on 7q, which is significantly related to lymph node metastasis of tumor. Gastric carcinoma-related tumor suppressor genes (TSGs) might locate near the locus. In order to seek gastric carcinoma-related TSGs in a further narrow region, LOH of microsatellite marker loci on chromosome 7q31 was examined in primary gastric carcinoma to determine the minimal commonly deleted regions, and the possible roles of these regional deletions in gastric carcinoma pathogenesis were analyzed in this study., Methods: Twelve microsatellite markers centering D7S486 locus on 7q31 region, with an average genetic distance of about 0.5 centimorgan (cM), were selected. DNAs were extracted from 78 specimens of gastric carcinoma and corresponding normal gastric mucosa tissues, amplified through multi-polymerase chain reaction (multi-PCR), and separated by electrophoresis. LOH of microsatellite marker loci was analyzed with GeneScan and Genotyper software to determine the minimal commonly deleted regions on 7q31. The possible roles of these regional deletions in gastric carcinoma pathogenesis were analyzed with consideration of clinicopathologic parameters., Results: LOH of all 12 selected microsatellite marker loci was detected in primary gastric carcinoma, with the total frequency of 41.7% (40/72). The most frequent LOH was D7S486 locus (located in 7q31.2), with the frequency of 30.4% (17/56); the second was D7S650 locus (located in 7q31.3), with the frequency of 21.1% (8/38). Two minimal commonly deleted regions, D7S2543-D7S486 and D7S480-D7S650 (each span about 90 kb), were detected on 7q31 in primary gastric carcinoma. The LOH frequency of D7S2543-D7S486 region was significantly related to clinical stage and lymph node metastasis (P = 0.01, P = 0.03); the LOH frequency of D7S480-D7S650 region was significantly related to clinical stage (P = 0.03), and LOH of this region occurred only in the patients with stage III/IV tumor, T3/T4 primary lesion, or lymph node metastasis., Conclusions: There are 2 minimal commonly deleted regions on 7q31 in primary gastric crcinoma, D7S2543-D7S486 and D7S480-D7S650. There might be TSGs in these 2 regions closely related to the progression of gastric carcinoma.

Background & Objective: Familial clustering of NPC has been widely observed, however, related investigations were mainly involved in individual reports for high-risk families or case-control study with small sample size, so no quantitive evaluation for NPC risk in relatives of high-risk families documented in high-risk area until now. The purpose of the study was to estimate NPC risk among relatives of high-risk pedigrees in Guangong province, so as to provide information for genetic epidemiology and clinical genetic consultation., Methods: One hundred and thirteen high-risk pedigrees were collected in the Cancer Center of Sun Yat-sen University, and standardized incidence ratio (SIR) was used to estimate NPC risk of first degree relatives (FDR)., Results: NPC risk was significantly higher in first degree relatives that in general population, and SIR was 37.55; in addition, SIRs were 50.72, 79.64, 7.12, and 33.58 in their brothers, sisters, fathers, and mothers respectively., Conclusion: NPC risk of relatives in familial NPC pedigrees elevates 7.12 to 79.64 times in high-risk families.