云南微小按蚊(Anopheles minimus)对5种杀虫剂敏感性基数调查

本文报道了云南微小按蚊对DDT、马拉硫磷(malathion)、杀螟硫磷(fenitrothion)、溴氰菊酯(deltamethrin)和二氯苯醚菊酯(permethrin)的敏感性测定。结果显示,潞西微小按蚊对菊酯类杀虫剂产生了不同程度的抗性。另外的3个杀虫剂,除元江品系对DDT表现为中度抗性外,其余均为敏感。     

HBV无症状携带者与ABO血型关系的探讨

目的：探讨ＨＢＶ无症状携带者与ＡＢＯ血型间关系。方法：采用Ｗｏｏｌｆ统计方法与卡方（ｘ＾２）检验方法对１７４例ＨＢＶ无症状携带者的ＡＢＯ血型分布以及男女性别的关系进行系统分析。结果：男性携带者血型呈Ｂ〉Ｏ〉Ａ〉ＡＢ型分布,女性携带者呈Ｂ〉Ａ〉Ｏ〉ＡＢ型分布。Ａ、Ｂ、Ｏ和ＡＢ血型人相对危险率分别是０．４８７０、２．０４１４、０．９６６８和１．７９５０。结论：ＨＢＶ无症状携带者与ＡＢＯ血型间存在一定关     

福州地区妇女解脲支原体感染情况及其药物敏感性分析

目的 了解福州地区妇女生殖道解脲支原体的感染及其药物敏感情况。方法 对福州地区１５２名生殖道炎症妇女和２７２名健康妇女,采集阴道或官颈分泌物,进行解脲支原体（Ｕｕ）培养及其对９种抗生素敏感性试验。结果 生殖道炎症妇女Ｕｕ阳性率６５．１３％,健康妇女阳性率４８．３５％．由生殖道炎症妇女检出的Ｕｕ对强力霉素最敏感（７８．７９％）,由健康妇女检出的Ｕｕ对阿奇霉素最敏感（１００．００％）。来自不同组妇女的     

Antimicrobial susceptibility and serogroups of Salmonella isolates from Riyadh, Saudi Arabia

The antimicrobial susceptibility and serogroups of 153 Salmonella strains isolated during a period of 22 months from both children and adults at a major teaching hospital in Riyadh, Saudi Arabia were studied. Antimicrobial susceptibility testing by comparative disc method and MIC determination by E-test method were performed on selected antimicrobial agents. For nalidixic acid and trimethoprim only the comparative disc method was used. Discrepancy between the two methods were noticed only in 1.3% of isolates. The majority of isolates from children (41%) were serogroup B, while those from adults (43%) were serogroup C1. The overall resistance was 16% to ampicillin and ampicillin/sulbactam, 13% to nalidixic acid, and 11% to chloramphenicol and trimethoprim/sulphamethoxazole. The resistance of Salmonella isolates to the so-called first line anti-Salmonella agents, i.e. ampicillin, chloramphenicol and trimethoprim/sulphamethoxazole, has increased compared to that reported 4 years ago from this Institution. Almost all isolates were susceptible to the second, and third generation cephalosporins, fluoroquinolones, aztreonam, mecillinam and gentamicin. Multiple drug resistance to two or more drugs was noticed in 16% of isolates, most of which were serogroup B. The majority of these multiple drug resistant isolates (96%) were ampicillin resistant and β-lactamase producers. Although these isolates showed reduced MICs to ampicillin/sulbactam, their MICs were still higher than the susceptibility breakpoint for this combination. The nalidixic acid-resistant isolates showed higher MICs to the fluoroquinolones compared to the nalidixic acid-sensitive isolates. Isolates from children showed higher resistance to some of the antimicrobial agents compared to those from adults.     

药敏纸片的质量控制研究

目的：探讨和研究药敏纸片质量控制的方法。方法：以克拉霉素药敏纸片为例，参照美国临床实验室标准化委员会(NCCLS)和联邦法规全书(CFR)的方法，建立一套药敏纸片质量控制的指标，包括鉴别、检查及含量测定。结果：采用专属性较强、灵敏度较高的TLC法进行鉴别，最低检出量为50μg；制订纸片的的直径、重量差异、含量均匀性及干燥失重作为检查项，采用短小芽孢杆菌(Bacillus pumilus)[CMCC(B)63202]作为检定菌，进行含量测定。结论：建立的克拉霉素药敏纸片质量标准能够控制其质量，可作为其他抗生素药敏纸片建立质量标准的参考。     

Variations in Prkdc and susceptibility to benzene-induced toxicity in mice.

Benzene, a carcinogen that induces chromosomal breaks, is strongly associated with leukemias in humans. Possible genetic determinants of benzene susceptibility include proteins involved in repair of benzene-induced DNA damage. The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), encoded by Prkdc, is one such protein. DNA-PKcs is involved in the nonhomologous end-joining (NHEJ) pathway of DNA double-strand break (DSB) repair. Here we compared the toxic effects of benzene on mice (C57BL/6 and 129/Sv) homozygous for the wild-type Prkdc allele and mice (129/SvJ) homozygous for a Prkdc functional polymorphism that leads to diminished DNA-PK activity and enhanced apoptosis in response to radiation-induced damage. Male and female mice were exposed to 0, 10, 50, or 100 ppm benzene for 6 h/d, 5 d/week for 2 weeks. Male mice were more susceptible to benzene toxicity compared with females. Hematotoxicity was evident in all male mice but was not seen in female mice. We observed similar, large increases in both micronucleated erythrocyte populations in all male mice. Female mice had smaller but significant increases in micronucleated cells. The p53-dependent response was induced in all strains and genders of mice following benzene exposure, as indicated by an increase in p21 mRNA levels in bone marrow that frequently corresponded with cell cycle arrest in G2/M. Prkdc does not appear to be a significant genetic susceptibility factor for acute benzene toxicity. Moreover, the role of NHEJ, mediated by DNA-PK, in restoring genomic integrity following benzene-induced DSB remains equivocal.     

GENETIC DELETION OF DETOXIFIC ENZYME GSTM1 AND GSTTI AS A HOST SUSCEPTIBLE FACTOR FOR NASOPHARYNGEAL CARCINOMA

Objective: To study the gene polymorphisms of GSTT1 and GSTM1 in nasopharyngeal carcinoma (NPC) patients and controls in an incidental area to evaluate the relationship between specific genotype and genotype combinations of these polymorphisms with the risk of NPC. Methods: Cases and controls all came from the Southwestern Guangxi. DNAs were extracted from their WBC. PCR technique was used to calculate the deletion rate of the two detoxific enzyme genes. Results: In this high risk area of NPC, the residents had high level deletion rates of 47.4% (64/135) Ml and T1 40.7% (55/135). The deletion rates were even higher in NPC patients, 61.5% (56/91) for Ml and 59.3% (54/91) for T1 respectively. There were statistical significances compared with control,P<0.05 andP<0.01 for Ml and T1 respectively. The difference was more significant in terms of combined Ml and T1 deletion between patients and controlsx ²=12.533,P=0.002. Conclusion: The combined deletion of detoxific enzyme genes GSTM1 and GSTT1 may be an important genetic susceptible factor for NPC in Guangxi. Biography: DENG Zhuo-lin (1929-), male, professor of pathology, Guangxi Medical University, majors in tumor pathology. E-mail :zhuolin@hotmail.com     

细胞色素P450 3A4基因多态性及与肝癌易感性研究

目的 探讨细胞色素P450 3A4(CYP3A4)基因的多态性与肝癌的关系。方法 应用聚合酶链反应（PCR）、变性梯度凝胶电泳（DGGE）、单链构象多态（SSCP）和DNA测序技术，对84例肝癌患者和144例健康对照的CYP3A4基因的多态性进行了研究。结果 通过对CYP3A4基因10个外显子的检测，发现2例肝癌患者的第7外显子第15742位核苷酸发生了A→G转换，使得第183位氨基酸残基由天冬酰胺转变为丝氨酸；发现第10内含子存在一单核苷酸多态，表现第20338位核苷酸发生了G→A转换。病例组G／G、G／A和A／A基因型频率分别为59.52％,36.90%和3.58%；对照组则为59.72%，33.33%和6.95％。两组比较没有统计学差异。结论 CYP3A4基因可能高度保守，虽有突变，但属罕见。     

Polymorphisms in the glutathione S-transferase class mu and theta genes interact and increase susceptibility to lung cancer in minority populations (Texas, United States)

The genes coding for separate isoforms of both the human glutathioneS-transferase class mu and class theta enzymes (GSTM1and GSTT1) arepolymorphic with a variable ethnic distribution. These enzymes detoxifyreactive epoxides, including carcinogens produced by tobacco smoke. Becauseof this, the null polymorphism in the GSTM1 gene (coding for the glutathioneS-transferase class mu enzyme) has been studied widely as a possible sourceof inherited susceptibility to smoking-related lung cancer. The more recentlydescribed null polymorphism in the GSTT1 gene also could contribute to anincreased risk of smoking-related lung cancer. As the incidence of lungcancer is known to differ by ethnicity, we have conducted a case-controlstudy in the United States of 108 African-Americans (Blacks) and 60Mexican-Americans (Hispanics) with lung cancer and 132 African-American(Black) and 146 Mexican-American (Hispanic) controls to investigate theassociation of the GSTT1 and GSTM1 polymorphi sms with lung cancer inminority populations. In the unadjusted data, there was a borderlinesignificant association of the GSTM1 null polymorphism with lung cancer inMexican-Americans (odds ratio [OR] = 1.8, 95 percent confidence interval [CI]= 1.0-3.3 ) that was not observed in African-Americans. The GSTT1 nullpolymorphism also had a higher prevalence in cases than controls in bothracial/ethnic groups, but this increase was not statistically significant.When the data were analyzed using logistic regression controlling for age,gender, race, and smoking, no significant association of either trait withlung cancer was observed, with ORs for both traits of approximately 1.3.However, when the prevalence of individuals who were null for bothpolymorphisms was compared by case status, a significant interaction wasobserved. Logistic regression models showed the OR for the association oflung cancer and the presence of both null polymorphisms compared with one(either GSTT1 or GSTM1) or no null genotype to be 2.9 (P < 0.04). Theseresults suggest that there may be carcinogenic intermediates in cigarettesmoke that are substrates for both the GSTT1 and GSTM1 enzymes, and that lungcancer risk is increased more than additively for individuals who have bothGSTT1 and GSTM1 null polymorphisms.     

Azoxymethane-induced colon tumors and aberrant crypt foci in mice of different genetic susceptibility

Azoxymethane (AOM) is an organotropic colon carcinogen that is commonly used to induce colon tumors in rodents. Unlike its parent compound, 1,2-dimethylhydrazine (DMH), a tumor susceptibility phenotype in inbred mice with respect to AOM has not been established. Thus, this study was undertaken to determine whether genetic susceptibility extends to this carcinogen. SWR/J, A/J (both susceptible to DMH carcinogenesis) and AKR/J (resistant) mice were treated with 10 mg/kg AOM i.p. once a week for 8 weeks. Twenty-five weeks after the initial injection, tumor yield was determined. With a single exception, only SWR/J and A/J mice developed tumors, with a distribution that was limited to the distal colon (16.3±1.1 and 36.4±2.4, respectively). The formation of aberrant crypt foci (ACF), putative preneoplastic lesions, was also assessed in whole-mount colons using Methylene Blue staining. Consistent with tumor multiplicity, the total number of ACF was highest in A/J mice, followed by SWR/J mice. In addition, A/J mice had a significantly greater number of large ACF (five or more crypts per foci) than the other strains. Despite the absence of colon tumors, however, AKR/J mice did develop a significant number of ACF. This finding suggests that ACF in resistant mice are persistent but do not progress to tumors.