Inhibition of ligand binding to g protein-coupled receptors by arachidonic acid

Arachidonic acid (AA), released in response to muscarinic acetylcholine receptor (mAChR) stimulation, previously has been reported to function as a reversible feedback inhibitor of the mAChR. To determine if the effects of AA on binding to the mAChR are subtype specific and whether AA inhibits ligand binding to other G protein-coupled receptors (GPCRs), the effects of AA on ligand binding to the mAChR subtypes (M₁, M₂, M₃, M₄, and M₅) and to the μ-opioid receptor, β₂-adrenergic receptor (β₂-AR), 5-hydroxytryptamine receptor (5-HTR), and nicotinic receptors were examined. AA was found to inhibit ligand binding to all mAChR subtypes, to the β₂-AR, the 5-HTR, and to the μ-opioid receptor. However, AA does not inhibit ligand binding to the nicotinic receptor, even at high concentrations of AA. Thus, AA inhibits several types of GPCRs, with 50% inhibition occurring at 3–25 μM, whereas the nicotinic receptor, a non-GPCR, remains unaffected. Further research is needed to determine the mechanism by which AA inhibits GPCR function.     

广东地区肝炎患者血清中庚型肝炎病毒RNA的检测

目的了解庚型肝炎病毒（ＨＧＶ）感染在不同临床类型肝炎患者中的存在状况。方法用逆转录－聚合酶链反应（ＲＴ－ＰＣＲ）技术对７２１例肝炎患者血清进行了ＨＧＶＲＮＡ检测。结果发现８０例ＨＧＶＲＮＡ阳性，以非甲、乙、丙、丁或戊型肝炎中阳性率为高；慢性丙型肝炎（ＨＣＶ）和慢性乙型混合丙型肝炎（ＨＢＶ＋ＨＣＶ）次之；在慢性重型肝炎和肝硬化时较低。结论庚型肝炎病毒在广东地区现症肝炎患者中有一定程度的流行     

Identification of GRASP-1 as a novel 97 kDa autoantigen localized to endosomes

We have identified an autoantigen that is recognized by antibodies from an 18-year-old female with a history of recurrent infections who later in her clinical course developed Raynaud's phenomenon and telangiectasias. By indirect immunofluorescence (IIF), the index serum produced a unique cytoplasmic discrete speckled (CDS) staining pattern that partially colocalized with early endosome antigen 1 (EEA1) but not Golgi complex or other cytoplasmic organelles in HEp-2 cells. When HEp-2 cells were treated with 0.1 N HCl, the cytoplasmic speckled staining of the index serum was markedly decreased, suggesting that the reactive antigen was soluble. Western blot analysis showed a reactive approximately 97 kDa protein in a saline soluble protein preparation from HeLa cells. Mass spectrometric analysis of the excised 97 kDa band that was immunoprecipitated from HeLa cell extracts identified GRASP-1 as a possible target. The index serum and anti-GRASP-1 antibodies colocalized to structures in the cytoplasm of HEp-2 cells. Synthetic peptides representing the full-length GRASP-1 protein were used to identify reactive epitopes. Like many other cytoplasmic autoantigens, GRASP-1 has numerous coiled-coil domains throughout the protein with the exception of short segments at the amino and carboxyl terminus.     

临床诊断为非甲～戊型肝炎患者的病原学研究

目的探讨临床诊断为非甲-戊型肝炎患者的病原学。方法 采用巢式PCR（nPCR)检测HBV、TTV、B19、和SENV DNA；用逆转录巢式PCR（RT-nPCR)检测HGV和HCV RNA。结果 60例临床诊断为非甲-戊型肝炎患者中，单独HBVDNA阳性30例（阳性率为50.0%)，HBV和TTVDNA阳性10例（16.7%)，HBV和B19DNA阳性6例（10.0%)，HCVRNA、HBV和SENVDNA阳性1例（1.7%)，单独HCVRNA阳性1例（1.7%)，HCVRNA和B19DNA阳性1例（1.7%),HGVRNA无一例阳性，单独B19DNA阳性2例（3.3%)。单独TTVDNA阳性1例（1.7%)，另8例（13.3%)上述病毒核酸均为阴性。HBV合并感染TTV或B19对其血清学生化指标无影响。结论HBV是临床诊断为非甲-戊型肝炎的主要病原，HGV、TTV、B19和SENV与非甲-戊型肝炎无关。     

新生儿G6PD缺陷病和晚发性维生素K缺乏症的特点与预防

目的 探讨新生儿C6PD缺陷病和晚发性维生素K缺乏症的危害与预防措施。方法 回顾分析1995-2000年儿内科住院的1周-2月(不含2月)的婴儿3104例次，其中病死56例。结果 1周-2月的小婴儿占住院患儿的19．34％，其中新生儿G6PD缺陷病239例，占7．70％；晚发性维生素K缺乏症92例，占2．96％。死因的第2、3位分别是晚发性维生素K缺乏症(13例，占23．21％)和新生儿C6PD缺陷病(12例，占21．43％)，两者的病死率分别为14．13％和5．02％，极显著高于(x^2＝17．59，P＜0．01)或相近于(x^2＝0．88，P＞0．05)肺炎的3．57％。新生儿G6PD缺陷病合并感染占38．49％、低氧血症占23．35％、低血糖占19．25％、酸中毒占15．90％，继发胆红素脑病占13．81％。晚发性维生素K缺乏症出现抽搐占90．22％、胃肠、注射部位出血占60．89％；CT证实颅内出血占98．91％。结论 1周-2月的小婴儿约占住院患儿的两成，新生儿G6PD缺陷病和晚发性维生素K缺乏症的病死率均很高，两者是除肺炎外最主要的死因。提议制定并推广预防这2种疾病的常规措施，并参照国内外相应的现状拟出其具体内容。     

应用荧光斑点法和比值法检测G6PD

目的建立适合于G6PD缺乏的新生儿筛查及确诊方法。方法应用荧光斑点法(FST)对新生儿筛查滤纸干血片进行检测，对可疑阳性者召回，抽静脉血以D6PD／6PGD比值法进行确诊，同时结合新生儿父母亲的G6PD结果，根据遗传关系综合分析。结果FST筛查25000例新生儿，G6PD缺乏阳性率为4．56％，确诊检出率为4．09％。与比值法的符合率为90．4％，G6PD重度缺乏者的符合率为100％，G6PD中间缺乏者的符合率为78．5％，室间质量控制结果与反馈结果符合率为100％。结论FST汀具有高的敏感性、特异性和准确性，方法简便、快捷、费用低廉，可对滤纸干血片标本进行大规模的筛查检测，同时利用比值法进行确诊，可减少假阳性及假阴性，有利于早期诊断和防治G6PD缺乏所致的新生儿黄疸和急性溶血。     

Virion-bound ICAM-1 and activated LFA-1: a combination of factors conferring resistance to neutralization by sera from human immunodeficiency virus type 1-infected individuals independently of the disease status and phase

The role of the supplementary interaction between virion-bound host ICAM-1 and LFA-1 on target cells in sensitivity to neutralization of human immunodeficiency virus type 1 (HIV-1) is poorly studied. Serum samples from four long-term nonprogressors (LTNPs) and sequential sera from one progressor were used to assess neutralization sensitivity of isogenic ICAM-1-negative and ICAM-1-bearing HIV-1(NL4-3), a prototype of T-cell-line-adapted viruses. We found that virus neutralization sensitivity to the studied sera is not modified by the additional interaction between virally embedded ICAM-1 and LFA-1 under an inactive state. However, expression on the target cell surface of an activated LFA-1 form renders ICAM-1-bearing virus particles, but not viruses devoid of ICAM-1, more refractory to neutralization by sera from three out of four LTNPs and all sequential sera from the person who has experienced a progression of the HIV-1-associated disease. Although no conclusive correlation could be drawn between virus susceptibility to neutralization and the disease status or stages of HIV-1 infection, these findings demonstrate that other nonspecific virus-cell interactions mediated by virion-anchored host proteins and their normal cognate ligands on target cells represent factors that can affect the mechanism of HIV-1 neutralization.     

精神分裂症患者G72基因表达水平的研究

目的 本工作旨在检测精神分裂症（Schizophrenia）患者外周淋巴细胞中G72基因的表达情况，进而探讨G72基因的表达与精神分裂症的相关关系。 方法 工作在56例精神分裂症患者和84名年龄性别相匹配的对照中进行，在新鲜外周血样本中抽提总RNA，反转录成cDNA，基因表达量的检测在ABI Prism7900HT型序列监测系统上进行，采用TaqMan的方法对患者及对照组样本的mRNA进行定量，采集的荧光数据经SDS2.1软件自动处理，每个样本作三次平行检测，取平均值作为该样本的最终定量。数据应用SPSS统计软件进行处理，对组间基因表达水平的差异采用独立样本的T检验，调用本实验室G72基因单核苷酸多态性（SNPs）资料，用单因素方差分析的方法分析SNP与基因表达水平的关联性。结果 1.检测得到G72基因在对照组中的表达量为0.0586±0.0114amol/ng cDNA, 在精神分裂症患者组中的表达量为0.0498±0.0121amol/ng cDNA。2.经显著性检验， G72基因的表达水平在病例和对照组间差异无统计学意义，t=-0.512，df138，P=0.609，95%CI:-4.258~2.506。3.单因素方差分析结果显示，rs947267位置上的SNP与该基因的表达水平无相关，F=0.355，df2，χ2=0.703；而rs2181953位置上的SNP与G72基因表达水平相关联，F=6.275，df2，χ2=0.004。A/A基因型的患者基因表达水平显著高于其他基因型。结论：精神分裂症患者G72基因的表达量总体上较正常人并无显著变化，但rs2181953位置上的基因型会影响精神分裂症患者该基因的表达。     

Transcytosis and catabolism of antibody

This review describes the evolution of our knowledge of the transmission of immunoglobulin G (IgG) from mother to infant and the factors which regulate the persistence of IgG in the circulation. These apparently unrelated processes involve the same Fc receptor, FcRn (n=neonatal). FcRn appears to carry out these diverse roles by binding to IgG and then either transporting the bound IgG across cells (transcytosis) or recycling its cargo back to the cell surface (control of catabolism). IgG that is taken up by cells in the absence of binding to FcRn undergoes degradation. Thus, FcRn is the “protective” receptor that servesto maintain IgG homeostasis and deliver IgGs across cellular barriers.     

Dissociation of hepatitis A virus antigen-anti-HAV antibody complexes by 2-mercaptoethanol and dithiothreitol

Intravenous inoculation of two marmosets and one chimpanzee with hepatitis A virus (HAV) resulted in the replication of virus in liver, excretion of HAV particles in stool, and the appearance of circulating antibodies specific for hepatitis A. The development of an early antibody response in the chimpanzee and in one of the two infected marmosets was shown to interfere with the serologic detection of HAV antigen (HAV Ag) in homogenates of acute phase liver tissue obtained from these animals. Treatment of HAV Ag-positive and IgM anti-HAV-positive liver homogenates with thiol reducing compounds was shown to release HAV Ag from in vitro formed immune complexes. The increased RIA response for HAV Ag in homogenates treated with 2-mercaptoethanol (2-ME) or dithiothreitol (DTT) was further shown not to be due to activation of HAV Ag itself or to a nonspecific effect on the RIA coating antibody, radiolabeled probe, or homogenized liver tissue. IgG and IgM double-antibody sandwich RIAs for HAV Ag were also compared for their ability to detect HAV Ag under reducing and nonreducing conditions. Application of the 2-ME or DTT treatment procedure to the serologic detection of other viral antigens or viruses whose presence in blood, stool, tissue macerate, or other milieu may be masked by specific antibody appears to be feasible.