Sensitive Detection of p53 Gene Mutations in Esophageal Endoscopic Biopsy Specimens by Cell Sorting Combined with Polymerase Chain Reaction Single-strand Conformation Polymorphism Analysis

For the rapid and sensitive detection of p53 gene mutations in esophageal endoscopic biopsy specimens, we combined cell sorting with the polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis. Mutations in exons 5–8 of the p53 gene were investigated by FCR-SSCF analysis using 10³ sorted nuclei obtained from each endoscopic biopsy specimen of 16 patients with esophageal cancer. DNAs extracted from their respective surgical specimens were investigated by a conventional method of PCR-SSCP analysis. Mutations in the biopsy specimens were detected in 6 of the 12 aneuploid tumors but in none of the 4 diploid tumors. After tumor cell enrichment by cell sorting, one mutation in exon 8 became apparent, which could not be detected from the surgical specimen by a conventional method of PCR-SSCP analysis. This method should improve the sensitivity of detecting p53 gene mutations, and provides additional information concerning the DNA ploidy pattern in the tumors.     

人类乳头瘤病毒16,18型,p53基因与胃癌

３０例新鲜胃癌标本，采用多聚酶链反应技术检测人类乳头瘤病毒１６、１８感染、并采用多聚酶链反应－单链构象多态性技术对ｐ５３基因突变进行检测。结果：ＨＰＶ１５阳性率为４０．０％，未发现ＨＰＶ１８感染：Ｐ５３基因突变率为５０．０％，ＨＰＶ１６感染和Ｐ５３基因突变同时存在者为１６．７％。     

Pheophytin a, a low molecular weight compound found in the marine brown alga Sargassum fulvellum, promotes the differentiation of PC12 cells

We identified and characterized a neurodifferentiation compound from the marine brown alga Sargassum fulvellum collected from the Japanese coastline. Several instrumental analyses revealed the compound to be pheophytin a. Pheophytin a did not itself promote neurite outgrowth of PC12 cells. However, when PC12 cells were treated with a low concentration of pheophytin a (3.9 microg/ml) in the presence of a low level of nerve growth factor (10 ng/ml), the compound produced neurite outgrowth similar to that produced by a high level of nerve growth factor (50 ng/ml). Pheophytin a also enhanced signal transduction in the mitogen-activated protein kinase signaling pathway, which is also induced by nerve growth factor. The effect of pheophytin a on neurite outgrowth of PC12 cells was completely blocked by U0126, a representative mitogen-activated protein kinase kinase inhibitor. These results suggest that pheophytin a enhances the neurodifferentiation of PC12 cells in the presence of a low level of nerve growth factor and that this effect is mediated by activation of a mitogen-activated protein kinase signaling pathway.     

VEGF和p53在胰腺癌中的表达及意义

目的　探讨胰腺癌组织中血管内皮生长因子 (VEGF)及p5 3蛋白的表达及其临床病理意义。方法　采用SP免疫组织化学方法 ,对 46例胰腺癌组织中VEGF及 p5 3蛋白的表达进行检测。结果　VEGF与 p5 3表达率分别为 65 .2 %和 5 8.7%。p5 3表达与VEGF表达呈明显正相关(P <0 .0 5 )。VEGF表达与胰腺癌淋巴结转移 (P <0 .0 5 )和远处转移 (P <0 .0 1)显著相关 ,而与肿瘤大小 ,病理学分级无关 ,p5 3表达与胰腺癌远处转移 (P <0 .0 5 )显著相关 ,而与肿瘤大小 ,病理学分级及淋巴结转移无关。结论　在胰腺癌中 ,VEGF表达与 p5 3蛋白的表达呈正相关 ,在胰腺癌的转移中起重要作用     

老年2型糖尿病患者胰岛素抵抗相关指标的检测和意义

目的:探讨老年2型糖尿病胰岛素抵抗(IR)及其相关性,为老年2型糖尿病的合理防治提供临床依据。方法:选择120例老年2型糖尿病患者,按胰岛素敏感指数(HOMA)胰岛素抵抗(HOMA-IR)50百分位点将患者分为两组:胰岛素相对敏感组(HOMA-IR<3.56)和胰岛素相对抵抗组(HOMA-IR≥3.56),比较体重指数(BMI)、腰/臀比(WHR)、血压、血生化学检查等指标。用年龄>40岁,<60岁的2型糖尿病患者做对照组。结果:两组老年患者在年龄、性别、舒张压、空腹血糖、胆固醇、高密度脂蛋白、糖化血红蛋白、HOMA胰岛β细胞功能方面无差异;但BMI、WHR、收缩压、甘油三脂、空腹胰岛素、HOMA-IR差异具有显著性。多线性回归分析后,只有腰/臀比、收缩压、甘油三脂、HOMA-IR存在统计学差异。老年患者与对照组相比,IR发生率明显增加,且两者腰/臀比、收缩压、甘油三脂方面也差异显著。结论:IR与老年2型糖尿病密切相关,是临床防治糖尿病的重要靶点。     

肝癌及癌旁组织中P~(53)基因第七外显子转录水平的表达差异及临床意义

目的 :研究启东区肝癌中 P53基因第七外显子转录水平的表达及其与患者临床病理特征间的关系。方法 :通过 RT- PCR确定 P53基因第七外显子在 47对肝癌标本中的表达 ,并分析其与肝癌患者临床病理特征间的关系。结果 :P53基因第七外显子在肝癌及其癌旁组织中均显示差异表达 ,其中 1 7例为上调表达 ,30例为下调表达 ,上下调表达之间差异显著 ;女性、年龄≥ 45岁、AFP( + )、HBs Ag( + )、癌栓 ( + )、肝硬化、病理 Edmondson's 级的病例中 P53基因第七外显子均呈显著下调表达 ;Edmondson's I级病例肝癌组织中 P53基因的 EI显著高于 Edmondson's 级病例。结论 :启东肝癌中 P53基因第七外显子转录水平上存在表达差异 ,且其异常表达与肝癌的临床病理特征有关     

突触功能必需基因参与线虫衰老的调控(英文)

目的鉴定参与线虫衰老的神经内分泌调控的新基因。方法鉴于神经系统在衰老调控中的重要作用,通过寿命分析和脂褐质自发荧光的检测,从编码突触蛋白的遗传位点中筛选参与衰老调控的基因。我们还进一步检查了这些遗传位点相应的突变体的永久性幼虫形成情况,探讨它们是否可能受胰岛素样信号通路的调控。结果遗传位点 unc-10,syd-2,hlb-1,dlk-1,mkk-4,scd-2,snb-1,ric-4,nrx-1,unc-13,sbt-1,unc-64 可能参与线虫衰老的调控。而且在衰老的调控中,unc-10,syd-2,hlb-1,dlk-1,mkk-4,scd-2,snb-1,ric-4,nrx-1 的功能可能与unc-13,sbt-1,unc-64相反。肠道脂褐质自发荧光的检测进一步证明了筛选出的各基因对应突变体的长寿或短寿表型,是由减慢或缩短的组织衰老所致。在筛选出的基因中,syd-2,hlb-1,mkk-4,scd-2,snb-1,ric-4,unc-64 也参与了永久性幼虫形成的调控。另外,daf-2突变增强了syd-2和hlb-1的表达,降低了mkk-4,nrx-1,ric-4,sbt-1,rpm-1,unc-10,dlk-1,unc-13 的表达。daf-16突变提高了syd-2和 hlb-1 的表达,降低了mkk-4,nrx-1,sbt-1,rpm-1,unc-10,dlk-1,unc-13 的表达. 结论突触功能可能在个体寿命和永久性幼虫形成的调控机制中具有重要的作用。     

火箭推进剂呼吸防护装备研究现状及发展趋势

本文对呼吸防护装备的应用、发展进行了综述，分析了火箭推进剂毒性对呼吸防护的要求和国内推进剂呼吸防护研究现状，对推进剂专用呼吸防护装备的发展趋势进行了探讨。     

Deregulation of cell proliferation by polycyclic aromatic hydrocarbons in human breast carcinoma MCF-7 cells reflects both genotoxic and nongenotoxic events.

Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), are carcinogens suggested to be involved in development of human cancer. Several recent studies have reported that PAHs can activate estrogen receptors (ER), either directly or indirectly by producing estrogenic metabolites. We hypothesized that the activation of ER by PAHs or their metabolites could induce cell proliferation in estrogen-sensitive cells. In the present study, we found that two PAHs, benz[a]anthracene (BaA) and BaP, can stimulate proliferation of human breast carcinoma MCF-7 cells at concentrations 100 nM and higher. This effect was ER-dependent, because it was blocked by the pure antiestrogen ICI 182,780. Although both PAHs partially inhibited S-phase entry and DNA synthesis induced by 17beta-estradiol, they stimulated S-phase entry when applied to MCF-7 cells synchronized by serum deprivation. This was in contrast with model antiestrogenic aryl hydrocarbon receptor ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin, which fully suppressed S-phase entry. BaP, which is a strong mutagen, was found to induce p53 tumor suppressor expression, a partial S-phase arrest and at higher concentrations also cell death. Pifithrin-alpha, a synthetic inhibitor of p53 activity, abolished both S-phase arrest and apoptosis induced by genotoxic PAHs, and it potentiated the proliferative effect of BaP. Thus, both genotoxic and nongenotoxic events seem to interact in the effects of BaP on cell proliferation. Taken together, our data indicate that both BaA and BaP can stimulate cell proliferation through activation of ER. The proliferative effects of these carcinogenic compounds might contribute to tumor promotion in estrogen-sensitive tissues.