Assembly of plasmin-generating proteins on the surface of human endothelial cells.

Traditionally, plasmin generation has been conceptualized as a process oriented on the surface of a fibrin-containing thrombus. Recent work, however, indicated that plasminogen and its activators, tissue plasminogen activator (t-PA) and urokinase, can assemble on the surface of cultured human umbilical vein endothelial cells (HUVECs). On binding to HUVECs, plasminogen is activated by t-PA approximately 12-fold more efficiently than fluid-phase plasminogen, and is converted to a plasmin-modified form, possibly unique to cell surfaces. In addition, t-PA interacts with HUVECs at two sites. The major binding site preserves its activity and represents a true (relative molecular weight 40,000) membrane-associated exoreceptor. The low-density lipoprotein (LDL)-like lipoprotein, lipoprotein(a), is highly associated with atherosclerosis, bears striking sequence homology to plasminogen, and competes with plasminogen for cell surface binding. In summary, functional assembly of plasminogen and t-PA may represent an important thromboregulatory system.     

HIV-1核心抗原p24基因的表达、纯化及抗原性分析

目的在原核系统中表达全长HIV-1 p24抗原,并对其抗原性进行鉴定。方法利用PCR技术从HIV-1全基因质粒(BH-10)中扩增p24抗原基因,通过酶切消化后连接到表达载体pET22b上,用此连接产物转化大肠埃希菌BL21(DE3),经IPTG诱导,表达p24抗原。运用双酶切技术、SDS-PAGE电泳检测插入基因片段的正确性,并用W estern B lot(WB)及ELISA法对表达产物的抗原性进行检测。结果PCR产物和构建的重组质粒pET22b-p24经双酶切插入的外源基因片段均为690 bp,与预期p24抗原全基因片段大小一致。纯化蛋白SDS-PAGE电泳,可见1条相对分子量约26×103的外源表达蛋白带,与预期大小一致,未见杂蛋白带。WB结果显示重组蛋白与HIV-1阳性血清呈特异性反应,与健康人血清没有反应。ELISA检测p24抗原灵敏度为93.94%(62/66),特异性为93.33%(28/30)。结论构建了HIV-1 p24表达载体pET22b-p24,并在原核细胞中高效表达,其表达产物具有良好的抗原性,为研制HIV抗体确认试剂奠定了良好的基础。     

Viral infections in short-term injection drug users: the prevalence of the hepatitis C, hepatitis B, human immunodeficiency, and human T-lymphotropic viruses.

OBJECTIVES: The purpose of this study was to estimate the prevalence and correlates of four blood-borne viral infections among illicit drug injectors with up to 6 years of injecting experience. METHODS: We analyzed data from 716 volunteers recruited in 1988 and 1989. Test results for hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus, type 1 (HIV), and human T-lymphotropic virus types I and II (HTLV) were examined across six sequential cohorts defined by duration of drug injection. RESULTS: Overall, seroprevalence of HCV, HBV, HIV, and HTLV was 76.9%, 65.7%, 20.5% and 1.8%, respectively, and 64.7%, 49.8%, 13.9%, and 0.5%, respectively, among those who had injected for 1 year or less. Among the newest initiates, HCV and HBV were associated with injecting variables, and HIV was associated with sexual variables. CONCLUSIONS: The high rates of HCV, HBV, and HIV infections among short-term injectors emphasizes the need to target both parenteral and sexual risk reduction interventions early. Renewed efforts at primary prevention of substance abuse are indicated.     

Seroprevalence of hepatitis B and C, and human immunodeficiency type 1 viruses in a rural population from the Republic of Equatorial Guinea.

The seroprevalence of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) markers was evaluated in a group of 2042 subjects from a rural area in the Republic of Equatorial Guinea, to obtain a better understanding of the transmission patterns of these viruses. Antibodies to HIV-1 were detected in 12 subjects (0.6%); the seroprevalence did not differ significantly by age or gender. Overall seroprevalence for HCV was 1.7% (in patients aged > 40 years, 5.6%). Hepatitis B surface antigen was detected in 8.8% of subjects, with the higher seroprevalence in children aged < or = 18 years of 13.4% contrasting with the higher seroprevalence of HCV in older subjects of the Equatoguinean studied population. These results indicate differences in the distribution of the viruses and, probably, different routes of transmission. The study demonstrates the existence of a high HBV carrier rate in children, concluding that hepatitis B vaccine should be incorporated into the Expanded Programme on Vaccination in Equatorial Guinea.     

Salivary and urinary diagnosis of human immunodeficiency viruses 1 and 2 infection in C?te d'Ivoire, using two assays.

This investigation, done at the Institut Pasteur de Cote d'Ivoire 'blind' of the previous serological findings, suggests that GACELISA, a commercial immunoglobulin G capture enzyme immunoassay for anti-human immunodeficiency virus antibody, can be successfully applied to unprocessed saliva and urine specimens. Its accuracy may be as high as that of conventional enzyme assays on serum tested under similar conditions. However, the role of GACPAT, a similar assay, as a cheap alternative screening test for urine remains in doubt unless its non-specificity can be controlled.     

脑胶质瘤中p16与p53及增殖细胞核抗原蛋白的表达和意义

目的探讨p16与p53及增殖细胞核抗原(PCNA)在人脑胶质瘤中的表达及意义。方法用免疫组织化学手段检测114例不同级别脑胶质瘤组织中p16和p53、PCNA蛋白的表达,并其与肿瘤不同级别的关系。结果p16蛋白表达缺失在Ⅲ级(65.6%)、Ⅳ级(91.3%)脑胶质瘤中显著高于Ⅰ~Ⅱ级的缺失(33.3%)(P<0.01);p53蛋白表达在Ⅲ级(68.8%)、Ⅳ级(89.1%)脑胶质瘤中显著高于Ⅰ~Ⅱ级的表达(27.8%)(P<0.01);PCNA蛋白的表达在Ⅲ级(56.3%)、Ⅳ级(84.8%)脑胶质瘤中的表达强度显著高于Ⅰ~Ⅱ级(16.7%)的表达强度(P<0.01)。结论p16和p53、PCNA蛋白表达异常可用以判断人脑胶质瘤的生物学行为。     

锰对HUVEC-304细胞生长及p53、p21WAF1/CIP1蛋白表达的影响

目的探讨锰对人脐静脉内皮细胞系HUVEC-304细胞生长及p53、p21WAF1/CIP1蛋白表达的影响。方法取指数生长期HUVEC-304细胞,以100、200、400、800μmol/L MnCl2,分别作用24、48、72 h后,以四甲基偶氮唑蓝(MTT)比色实验检测细胞的存活力,筛选锰对细胞的毒性剂量。流式细胞仪(FCM)检测细胞凋亡,Western blot方法检测p53、p21WAF1/CIP1蛋白的表达。结果100、200、400、800μmol/L MnCl2作用24、48、72 h均对HUVEC-304细胞有显著的抑制作用(P<0.05),且呈剂量-时间效应关系。流式细胞仪检测结果表明锰能诱导HUVEC-304细胞凋亡(P<0.01),Western blot结果显示,随锰浓度的增高,p53蛋白的表达下降(P<0.05);而p21WAF1/CIP1蛋白表达上升,差异有统计学意义(P<0.05),且呈剂量依赖性。结论锰可抑制HUVEC-304细胞的增殖,诱导其发生凋亡,p53蛋白的表达减少及p21WAF1/CIP1蛋白的表达增加是其发生凋亡的机制之一。     

Association of hepatitis B surface antigen and core antibody with acquisition and manifestations of human immunodeficiency virus type 1 (HIV-1) infection

We examined the associations between seropositivity for hepatitis B virus (HBV) with the presence or development of antibodies to human immunodeficiency virus (HIV-1) and with HIV-1 induced T-helper lymphocyte deficiency or acquired immunodeficiency syndrome (AIDS). Serologic data on HBV and HIV-1, cytometric enumeration of CD4+ lymphocytes, clinical events (AIDS by Centers for Disease Control criteria) and hepatitis B vaccination histories were available on 4,498 homosexual participants in the Multicenter AIDS Cohort Study, Men were classified as to previous infection with HBV and prevalent or incident infection with HIV-1. Although there was an association between seropositivity for HBV infection and HIV-1 infection at enrollment (odds ratios anti-HBc 2.6; HBsAg 4.2), the relation between HBV seropositivity and subsequent seroconversion to HIV-1 was weaker (odds ratios 1.3 and 1.6). HIV-1 seroconversion was also associated with a history of certain other sexually transmitted diseases, but predisposing sexual practices did not account for the association between HBV and HIV-1 infection. Seropositivity for HBV infection at entry was not related to initially low or more rapid subsequent decline in T-helper lymphocyte counts and was not associated with an increased incidence of AIDS during 2.5 years of follow-up. History of vaccination against HBV did not appear to decrease susceptibility to HIV-1 infection or to subsequent progression of immunodeficiency. We conclude that prior HBV infection is unlikely to be specifically associated with acquisition of HIV-1 infection and is unrelated to more rapid progression of HIV-1-induced immunodeficiency.     

汉坦病毒核蛋白核心区域高效表达及产物鉴定

汉坦病毒是引起肾综合征出血热（HFRS）的主要病毒,汉坦病毒的基因由L、M、S三个片段构成,分别编码病毒RNA聚合酶,囊膜核蛋白G1和G2及核衣壳蛋白（简称核蛋白,Nucleocapsid Protein,NP）。血清学研究表明,汉坦病毒核蛋白具有很强的抗原性和免疫原性,同时NP抗原可以与汉坦病毒内的多种血清型病毒的免疫血清产生交叉反应,表明汉坦病毒的NP具有共同的抗原决定族。有鉴于此,我们对核蛋白的核心区域进行表达和纯化,并用SDS-PAGE和Western-Blotting对重组核蛋白进行鉴定,为其应用于诊断抗原提供技术依据。[第一段]     

Transmission of hepatitis B, hepatitis C and human immunodeficiency viruses through unsafe injections in the developing world: model-based regional estimates

Thousands of millions of injections are delivered every year in developing countries, many of them unsafe, and the transmission of certain bloodborne pathogens via this route is thought to be a major public health problem. In this article we report global and regional estimates of the number of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections that may occur from unsafe injections in the developing world. The estimates were determined using quantitative data on unsafe injection practices, transmission efficiency and disease burden of HBV, HCV and HIV and the prevalence of injection use obtained from a review of the literature. A simple mass-action model was used consisting of a generalized linear equation with variables accounting for the prevalence of a pathogen in a population, susceptibility of a population, transmission efficiency of the pathogen, proportion of injections that are unsafe, and the number of injections received. The model was applied to world census data to generate conservative estimates of incidence of transmission of bloodborne pathogens that may be attributable to unsafe injections. The model suggests that approximately 8-16 million HBV, 2.3-4.7 million HCV and 80,000-160,000 HIV infections may result every year from unsafe injections. The estimated range for HBV infections is in accordance with several epidemiological studies that attributed at least 20% of all new HBV infections to unsafe injections in developing countries. Our results suggest that unsafe injections may lead to a high number of infections with bloodborne pathogens. A major initiative is therefore needed to improve injection safety and decrease injection overuse in many countries.     

Effect of periodic vitamin A supplementation on mortality and morbidity of human immunodeficiency virus-infected children in Uganda: A controlled clinical trial

OBJECTIVE: We investigated whether vitamin A supplementation would decrease mortality and morbidity rates in children infected with the human immunodeficiency virus (HIV). METHODS: We conducted a randomized, double-blind, placebo-controlled clinical trial at Mulago Hospital, a large hospital that serves the urban and semiurban populations of Kampala, Uganda. One hundred eighty-one HIV-infected children were enrolled at 6 mo and randomized to receive vitamin A supplementation, 60 mg retinol equivalent, or placebo every 3 mo from ages 15 to 36 mo. Morbidity was assessed through a 7-d morbidity history every 3 mo, and vital events were measured. Children received daily trimethoprim-sulfamethoxazole prophylactic therapy. RESULTS: After age 15 mo, children were followed for a median of 17.8 mo (interquartile range = 11.1 to 21.0 mo). The trial was stopped when there was a new policy to implement a program of mass supplementation of vitamin A in the country. Mortality rates among 87 children in the vitamin A group and 94 children in the control group were 20.6% and 32.9%, respectively, yielding a relative risk of 0.54 (95% confidence interval, 0.30 to 0.98; P = 0.044) after adjusting for baseline weight-for-height Z score. Children who received vitamin A had lower modified point prevalences of persistent cough (odds ratio, 0.47; 95% confidence interval, 0.23 to 0.96; P = 0.038) and chronic diarrhea (odds ratio, 0.48; 95% confidence interval, 0.19 to 1.18; P = 0.11) and a shorter duration of ear discharge (P = 0.03). Vitamin A supplementation had no significant effect on modified point prevalences of fever, ear discharge, bloody stools, or hospitalizations. CONCLUSIONS: Vitamin A supplementation decreases mortality rate in HIV-infected children and should be considered in the care for these children in developing countries.     

Resting energy expenditure, caloric intake, and short-term weight change in human immunodeficiency virus infection and the acquired immunodeficiency syndrome.

To assess the causes of short-term weight loss in patients with acquired immunodeficiency syndrome (AIDS), we measured resting energy expenditure (REE), caloric intake, and the 28-d weight trend in control subjects, human immunodeficiency virus (HIV)+ subjects, AIDS patients, and AIDS patients during secondary infection (AIDS-SI). REE was increased in HIV+ (11%), AIDS (25%), and AIDS-SI (29%). Caloric intake was similar in control subjects, HIV+, and AIDS but reduced 36% in AIDS-SI, who consumed 17% fewer calories than their REE. Average short-term weight was stable for HIV+ and AIDS but decreased 5% in AIDS-SI. Weight trend correlated with caloric intake but not with REE. Thus HIV+ and AIDS are able to partially compensate for increased REE because they do not show short-term weight loss. Decreased caloric intake is critical for short-term weight loss and is seen during secondary infection. Inability of decreased caloric intake to decrease REE during infection accelerates short-term weight loss. Rapid weight loss with anorexia may be a harbinger of secondary infection in AIDS.     

Micronutrients and the pathogenesis of human immunodeficiency virus infection.

Micronutrient deficiencies may be common during human immunodeficiency virus (HIV) infection. Insufficient dietary intake, malabsorption, diarrhoea, and impaired storage and altered metabolism of micronutrients can contribute to the development of micronutrient deficiencies. Low plasma or serum levels of vitamins A, E, B6, B12 and C, carotenoids, Se, and Zn are common in many HIV-infected populations. Micronutrient deficiencies may contribute to the pathogenesis of HIV infection through increased oxidative stress and compromised immunity. Low levels or intakes of micronutrients such as vitamins A, E, B6 and B12, Zn and Se have been associated with adverse clinical outcomes during HIV infection, and new studies are emerging which suggest that micronutrient supplementation may help reduce morbidity and mortality during HIV infection.     

Protection of cotton rats by immunization with the human parainfluenza virus type 3 fusion (F) glycoprotein expressed on the surface of insect cells infected with a recombinant baculovirus.

The antigenicity, immunogenicity and efficacy of the human PIV3 fusion (F) glycoprotein expressed in insect cells by a baculovirus vector were studied. The results indicate that the PIV3 F glycoprotein expressed by a recombinant baculovirus is antigenically authentic as determined using a panel of PIV3 F specific monoclonal antibodies. Only a low level of antibody was stimulated by immunization of animals with infected cells, but the antibody appeared to be of high quality. Immunized animals were also moderately protected against PIV3 challenge. These results indicate that the baculovirus expression system is a reasonable source of authentic PIV3 F protein for use in a subunit vaccine.