Changes in HIV-1 incidence in heroin users in Guangxi Province, China

Guangxi Province, China recently experienced an outbreak of HIV-1 infection among heroin users. We studied HIV-1 incidence rates and associated risk factors for HIV-1 infection among heroin users residing in Pingxiang City. A total of 318 heroin users were followed from February 1998 through January 1999 (median follow-up: 8.1 months). Of these, 130 were prospectively followed from January through September 1999 (median follow-up: 8.3 months). HIV-1 and hepatitis C virus (HCV) incidence rates for each period were calculated. A generalized estimating equation approach was implemented to identify independent risk factors associated with HIV-1 infection across both periods. Among 318 study participants, 97.2% were men. The median age was 22 years. Approximately 60% reported sharing needles. HIV-1 prevalence at baseline was 15.4%. During the first follow-up period, HIV-1 incidence was 2.38 per 100 person years (py), and HCV incidence was 26.8 per 100 py. During the second follow-up period, HIV-1 incidence was 6.86 per 100 py, and HCV incidence was 28.9 per 100 py. After controlling for age and other factors, HCV seropositivity, history of sexually transmitted diseases, and sharing needles were independently associated with HIV-1 infection. These data suggest that HIV-1 incidence was rising over time in Pingxiang City, Guangxi Province. The high incidence of HCV heightens the importance of enhanced prevention programs to reduce injection and needle sharing among heroin users.     

Proteomic analysis of human skin fibroblasts grown on titanium: novel approach to study molecular biocompatibility

Despite the growing use of titanium as an implant material, there is a lack of consensus on what constitutes the molecular basis of its biocompatibility. In the present study we compared the response of skin fibroblasts to two different growth supporting surfaces: commercially pure titanium (cpTi) and tissue culture polystyrene (TCPS). Proteins from extracts of whole cells and adsorbed serum were separated and identified by 2-dimensional gel electrophoresis. In all, 40 proteins (46 spots) were identified by matrix-assisted laser desorption/ionization and mass spectrometry, database searching, immunoblotting, running a standard, or a combination of these techniques. Many of the proteins collected from the two surfaces were found to derive from the serum used in the culture medium. The surface properties of titanium appeared to promote the formation of a more concentrated carpet of serum proteins. Several proteins from bovine or human serum, such as albumin, alpha2-HS-glycoprotein, alpha-fetoprotein, plasminogen, thrombospondin 1, and serotransferrin, along with a few unidentified serum components, were found to adsorb onto cpTi in comparatively high concentrations. The adsorption of serum proteins did not appear to be selective on either substrate. We found that among the major cellular proteins, fibronectin and a cytoskeletal protein (non-muscle myosin heavy chain type A) were expressed at lower levels by fibroblasts grown on cpTi compared to TCPS. By analyzing the changes in the entire proteome of cells in response to different growth substrates, we may gain a better understanding of the molecular basis of biocompatibility.     

The P9 peptide sidechain specificity of I-Ad

The murine MHC class II variant I-Ad confers susceptibility to herpes simplex virus (HSV)-induced keratitis and relative protection against type 1 diabetes mellitus. The association to these autoimmune diseases appears to be largely determined by the peptide sidechain specificity of the P9 pocket, which we therefore have analyzed in detail. Assessment of T-cell responses and I-Ad binding capacity of position 446-substituted analogs of an IgG2a allotype b (IgG2a(b)) heavy chain peptide demonstrates that engagement of the P9 pocket is crucial for effective peptide presentation. Sidechain size rather than charge decides the capacity to engage the P9 pocket. Thus, small, uncharged sidechains are accepted, whereas acidic and aromatic amino acids as well as lysine and arginine are disfavored. The specificity of the P9 pocket of I-Ad (serine beta57) is distinct from that of the diabetes-associated I-Ag7 (aspartic acid beta57), supporting the contention that the polymorphism at residue beta57 influences diabetes susceptibility via P9-specific effects on the repertoires of self peptides presented to T cells. Furthermore, the data rationalize the susceptibility to HSV-induced keratitis conferred by the a and the protection conferred by the b allotypes of the IgG2a heavy chain. Keratitogenic T cells, which cross-react with the viral UL6 protein and a corneal antigen, are silenced in IgG2a(b) mice because of antigenic mimicry with gamma2a(b) 435-451. Our finding that the lysine P9 residue of the corresponding gamma2a(a) allopeptide precludes high-affinity binding to I-Ad indicates that the susceptibility of IgG2a(a) mice reflects inefficient thymic presentation of autologous IgG2a and thus failure to purge the T-cell repertoire of the pathogenic clones.     

有关冠状窦心导管术的应用解剖

对３０例成人心标本进行解剖，测得冠状窦口的纵径为１７．７９±４．６６ｍｍ，横径为８．７５±３．３９ｍｍ。发现冠状窦口朝向上或水平方向者占７０．００％；向下者占３０．００％，冠状窦瓣有新月状、半月状、网状、筛状和嵴状等五种形态。瓣高５．３１±４．１８ｍｍ，宽８．６２±２．４４ｍｍ。冠状窦的长度为３１．３３±１０．２２ｍｍ，最窄径为５．６０±１．０５ｍｍ；并有成角、缩窄和发育不良现象。其属支中有７３．３３％的心中静脉和１０．００％的心小静脉开口于冠状窦口处。本文并就冠状窦心导管术插管的成败因素进行了讨论。     

纳曲酮对移植排异反应的抑制作用

以小鼠心肌组织异位移植和混合淋巴细胞反应为整体和离体模型，观察了阿片受体阻断剂纳曲酮对移植排异反应的影响。结果显示：给动物从术前开始腹腔注射纳曲酮共１０天（每日二次，每次５ｍｇ／ｋｇ）可明显延长移植心肌组织的存活时间；加入纳曲酮（１０－４～１０－８ｍｏｌ／Ｌ）对混合淋巴细胞反应有抑制作用并呈量效关系。同时还观察到，给正常小鼠腹腔注射纳曲酮３天以上，可引起动物脾细胞由ＣｏｎＡ诱导的淋巴细胞转化反应受抑制。以上结果说明纳曲酮可抑制移植排异反应，此作用有可能是通过阻断内源性阿片肽所致。     

非悬滴开放式培养法在鸡胚背根节体外培养中的应用

本研究针对悬滴培养法在操作和应用上存在的问题和局限性，改用操作简便、适用范围广的非悬滴开放式培养法培养鸡胚背根节。将数个鸡胚背根节按一定间隔种植在内置生长基质盖玻片的35mm培养皿中，加人适量培养液，置于CO2。孵箱中进行培养。结果显示.从培养24h至60h各时期，培养皿中背根节生长状况均良好，神经突起明显增长，表明用非悬滴开放式培养法培养鸡胚背根节是可行且可靠的。     

脑内源性β-内啡肽对应激诱发促肾上腺皮质激素和催乳素释放的调节

在预先埋植第三脑室导管和预置颈外静脉导管的SD大鼠中,脑室内微量注射β-内啡肽抗血清,并与脑室内注射正常兔血清的大鼠对比。看到注射β-内啡肽抗血清后,ACTH和催乳素因限制性应激的释放,分别被抑制了46.1％和71.2％。说明中枢内源性β-内啡肽可能是ACTH和催乳素在某种应激时相伴释放的重要调节因素之一。     

Oestrogen infusions into the amygdala potentiate excitatory transmission from the accessory olfactory bulb to tuberoinfundibular arcuate neurones in the mouse.

We have previously shown that oestrogen increases the percentage of tuberoinfundibular (TI) arcuate neurones that respond to electrical stimulation of the accessory olfactory bulb (AOB). This study focuses on the amygdala as a possible site for the hormonal modulation of AOB input to TI arcuate neurones. Local infusions of 17 beta-oestradiol (30 pmol) into the amygdala of ovariectomized female mice significantly potentiated excitatory responses of TI arcuate neurones to AOB stimulation. This effect appeared rapidly (less than 10 min) after infusion. The inactive oestrogen isomer, 17 alpha-oestradiol, infused in the same manner, was without effect. These results suggest that oestrogen acts directly on amygdala neurones, thereby modulating olfactory information relayed along the vomeronasal pathway to TI arcuate neurones.     

Methodologic study of direct preparation for chromosome analysis of human solid brain tumors.

Human malignant glioma grown in athymic nude mice (NHG-1) and three freshly resected human solid gliomas were used in the study of factors influencing the direct preparation (DP) for chromosome analysis of human solid tumors. The results showed that: 1) the length of time after the blood supply was obstructed was a major factor in reducing the success rate of DP, i.e., a 2-hour delay resulted in a significantly lowered metaphase number and after 4 hours almost no metaphases could be seen; 2) preserving tumor cells at 4 degrees C may prolong the time limit to about 4 hours; 3) culture medium (RPMI 1640 and Eagle MEM) and bovine calf serum concentration (0%, 10%, 20%, and 30%) did not influence the success rate significantly; 4) colchicine concentration (0.025 micrograms/mL, 0.05 micrograms/mL, 0.1 micrograms/mL) and time of treatment (30 min, 90 min, or 180 min) mainly affected the quality of chromosomes observed but had little effect on the quantity of metaphases that might be obtained. Based on these results, we had a success rate of more than 80% in 72 xenografts and 22 human brain tumors.