Frequent Detection of Hepatitis C Virus Subtype 3a (HCV-3a) Isolates in Thailand by PCR Using Subtype-Specific Primers

By means of a polymerase chain reaction (PCR) method using subtype-specific primers for hepatitis C virus (HCV) subtypes 1a, 1b, 2a, 2b and 3a, the prevalence of each subtype among HCV isolates in Chiang Mai, Thailand, was determined. HCV-3a appeared to be the most common subtype in blood donors, and was also frequently found in patients with liver disease. HCV-1b, but not HCV-2a or ?2b, was also commonly found in this area, while a considerable percentage of the total HCV isolates still remained unclassifiable by the above methods. Serotype analysis of the HCV isolates using C14-1 and C14-2 recombinant peptides revealed that HCV-3a was likely to carry an antigenic determinant(s) different from those of the major types 1 (HCV-1a and ?1b) and 2 (HCV-2a and ?2b).     

Evaluation of the anti-hepatitis C virus effects of cyclophilin inhibitors, cyclosporin A, and NIM811

Hepatitis C virus (HCV) is a major causative agent of hepatocellular carcinoma. We recently discovered that the immunosuppressant cyclosporin A (CsA) and its analogue lacking immunosuppressive function, NIM811, strongly suppress the replication of HCV in cell culture. Inhibition of a cellular replication cofactor, cyclophilin (CyP) B, is critical for its anti-HCV effects. Here, we explored the potential use of CyP inhibitors for HCV treatment by analyzing the HCV replicon system. Treatment with CsA and NIM811 for 7 days reduced HCV RNA levels by 2-3 logs, and treatment for 3 weeks reduced HCV RNA to undetectable levels. NIM811 exerted higher anti-HCV activity than CsA at lower concentrations. Both CyP inhibitors rapidly reduced HCV RNA levels even further in combination with IFNalpha without modifying the IFNalpha signal transduction pathway. In conclusion, CyP inhibitors may provide a novel strategy for anti-HCV treatment.     

抑癌蛋白p16INK4a:一种新的衰老调控因子

p16INK4a是一种非常重要的抑癌蛋白．可通过抑制癌细胞的分裂和诱导癌细胞的死亡而减少癌症的发生,因此它的缺失或异常将增加患癌症的概率。最新的研究却发现,p16INK4a还有另外一个重要作用,通过诱发老龄哺乳动物干细胞功能下降而促使衰老的产生．至少在骨髓、前脑、胰岛细胞和角化细胞等类型细胞中被证实。这个发现使人们对p16INK4a功能和衰老分子机制有了新的理解,因此为更好的临床应用提供了重要的材料。     

p16INK4a基因的功能及其调控

p16INK4a蛋白能抑制CDK4和CDK6的活性,使pRb处于非磷酸化或低磷酸化状态而能与转录因子E2Fs结合,从而抑制DNA 的合成,阻止细胞由G1期进入S期.p16INK4a的表达受Ets1和Ets2的正调控,受Bmi-1的负调控.p16INK4a基因缺失、突变、甲基化、RNA剪接加工错误可导致细胞周期失控和癌变.应用p16INK4a对某些肿瘤进行基因治疗的研究正在进行中.     

A novel neuroprotectant PAN-811 protects neurons from oxidative stress

Hydrogen peroxide (H₂O₂), a major non-radical reactive oxygen species (ROS) could elicit intracellular oxidative damage and/or cause extracellular free calcium influx by activating the NMDA receptor or through calcium channels. In the present study, NMDA receptor antagonist MK-801 fully blocked H₂O₂-induced neuronal cell death, whereas green tea (GT) extract containing-antioxidants only partially suppressed the neurotoxicity of H₂O₂. These suggest that majority of ROS overproduction is downstream of H₂O₂-induced calcium influx. A novel neuroprotectant PAN-811 was previously demonstrated to efficiently attenuate ischemic neurotoxicity. PAN-811 hereby fully blocks H₂O₂-elicited neuronal cell death with a more advanced neuroprotective profile than that of GT extract. PAN-811 was also shown to protect against CaCl₂-elicited neurotoxicity. Efficient protection against oxidative stress-induced neurotoxicity by PAN-811 indicates its potential application in treatment of ROS-mediated neurodegenerative diseases. W.P. and C.M.D. had equal contributions to this project     

小鼠胚胎干细胞p16INK4a基因外显子1α打靶研究

在活体水平上 ,小鼠p16 INK4a基因是否具有抑制肿瘤发生和发展的功能是一个悬而未决的问题。利用筛选基因组文库得到的小鼠p16 INK4a基因组DNA片段 ,构建了针对小鼠p16 INK4a 基因外显子 1α的基因打靶载体 ,其短臂为1.5kbEco81Ⅰ AccⅡ片段 ,长臂为 5 .9kbXbaⅠ XhoⅠ片段。打靶载体经线性化和纯化后通过电穿孔转导小鼠R1ES细胞 ,获得 37个G418和Gancyclovir双药抗性克隆。用Southern杂交法对双药抗性克隆进行鉴定 ,获得一个敲除了p16 INK4a基因外显子 1α的阳性ES细胞克隆。     

Spontaneous hepatitis C viral clearance and hepatitis C chronic infection are associated with distinct cytokine profiles in Mexican patients

The mechanisms related to the spontaneous clearance of hepatitis C virus (HCV) havebeen primarily studied in regions where the infection is endemic. Results of priorstudies have been extrapolated to populations with low endemicity, such as Mexico.Herein, we determined the cytokine profiles in serum samples from Mexican patientswho spontaneously cleared HCV and patients chronically infected with HCV genotype 1a.Chronic HCV-infected patients displayed increased interleukin (IL)-8 and regulatedupon activation, normal T-cell expressed and secreted (CCL-5) secretion, whereaspatients who spontaneously cleared HCV showed augmented levels of IL-1 alpha, tumournecrosis factor-alpha, transforming growth factor-beta, monocyte chemoattractantprotein-2 (CCL-8), IL-13 and IL-15. Our study suggeststhat cytokine profiles maypredict disease outcome during HCV infection.     

聚乙二醇干扰素a-2a联合拉米夫定治疗HBeAg阳性慢性乙型肝炎疗效观察

目的目的观察聚乙二醇干扰素a-2a联合拉米夫定治疗HBeAg阳性慢性乙型肝炎疗效。方法采用开放、随机、对照临床试验。所选120例患者分为两组：PegIFNa-2a联合拉米夫定组（A组）和单用PegIFNa-2a组（B组）。分别在治疗12周、24周、治疗52周停药及停药后随访26周时进行疗效评价。结果A、B组治疗结束时HBVDNA阴转率分别为86．7％（52／60）、53．3％（32／60）;ALT复常率88．3％（53／60）、60％（36／60）;HBeAg阴转率70％（42／60）、38．3％（23／60）;HBsAg阴转率26．7％（16／60）、11．7％（7／60）;抗-HBs阳转率分别为23．3％（14／60）、8．3％（5／60）;抗-HBeAb阳转率分别为65．0％（39／60）、35．0％（21／60）,差异均具有统计学意义（P〈0．01或P〈0．05）。结论PegIFNa-2a联合拉米夫定治疗HBeAg阳性慢性乙型肝炎的疗效优于单用Peg IFNa-2a     

Proteoglycan synthesis by normal and neoplastic human transitional epithelial cells

Metabolically 35S-labeled proteoglycans were isolated from cell-associated matrices and media of confluent cultures of human normal transitional epithelial cells and HCV-29T transitional carcinoma cells. On Sepharose CL-4B columns, the cell-associated proteoglycans synthesized from both cell types separated into three identical size classes, termed CI, CII, and CIII. Normal epithelial cell C-fractions eluted in a 22:34:45 proportion and contained 64%, 64%, and 72% heparan sulfate, whereas corresponding HCV-29T fractions eluted in a 29:11:60 proportion, and contained 91%, 77%, and 70% heparan sulfate, respectively. Medium proteoglycans from normal cells separated into two size classes in a proportion of 6:94 and were composed of 35% and 50% heparan sulfate. HCV-29T medium contained only one size class of proteoglycans consisting of 23% heparan sulfate. The remaining percentages were accounted for by chondroitin/dermatan sulfate. On isopycnic CsCl gradients, proteoglycan fractions from normal cells had buoyant densities that were higher than the corresponding fractions from HCV-29T cells. DEAE-Sephacel chromatography showed that cell and medium associated heparan sulfate from HCV-29T cells was consistently of lower charge density (undersulfated) than that from normal epithelial cells. In contrast, the chondroitin/dermatan sulfate of HCV-29T was of a charge density similar to that of normal cells. These as well as other structural and compositional differences in the proteoglycan may account, at least in part, for the altered behavioral traits of highly invasive carcinoma cells.     

长效干扰素对CHB患者CD4^＋T细胞ICOS表达及血清IFN-γ、IL-4水平的影响

目的探讨长效干扰素对慢性乙型肝炎患者外周血CD4^＋T细胞上ICOS表达及血清IFN-γ、IL-4水平的影响。方法慢性乙型肝炎患者52例,其中聚乙二醇干扰素α2a治疗28例,常规治疗24例,另征集健康志愿者20例为正常对照组。采集治疗前及治疗后24、48周的患者外周血,以FCM检测ICOS^＋CD4^＋T细胞在PBMC中的频数变化;以ELISA检测治疗前后患者血清中IFN-γ、IL-4的水平变化;以Realtime—PCR检测患者HBV—DNA载量变化。结果慢性乙肝患者CD4^＋T细胞ICOS表达水平明显高于正常对照者（P〈0．001）,干扰素治疗者48周时ICOS表达水平低于常规治疗者,差异有统计学意义（P〈0．01）。经干扰素治疗后,患者Th1细胞因子IFN-γ水平升高,与常规治疗者相比有差异有统计学意义（P〈0．001）;而Th2细胞因子IL-4水平逐渐降低,与常规治疗者相比差异有统计学意义（P〈0．001）。干扰素治疗者ICOS、HBV-DNA载量变化值同IFN-γ水平的变化值呈负相关（P〈0．001）,而与IL4水平的变化值则为正相关（P〈0．001）。结论慢性乙肝患者存在着细胞免疫紊乱,干扰素治疗可以在一定程度纠正患者体内的Th2偏移,降低CD4^＋T细胞上ICOS的表达,促进IFN-γ表达,发挥抗病毒作用。     

细胞衰老的重要通路:p16INK4a/Rb和p19ARF/p53/p21Cip1信号途径

细胞周期蛋白依赖激酶（cyclin-dependent kinase,CDK)抑制因子p16^INK4a,p21^Cipl等是细胞衰老的关键效应物。本文对涉及这些抑制物的两条衰老诱导途径作一综述,它们是p16^INK4a/Rb和p19^ARF/p53/p21^Cipl信号途径。其中,几个抑癌基因的产物R ,16^INFK4a,p53及p19^ARF处于两条途径的核心位置。