Inhibition of cleavage of the third component of human complement (C3) by its small cleavage fragment, C3a: inhibition occurs with the classical-pathway, but not the alternative-pathway, C3 convertase

Activation of the third component of complement (C), C3, is central to the functioning of the C system in inflammation. Cleavage of C3 by the C3 convertases of both the classical and alternative pathways results in the formation of two split products, C3b and C3a. C3a inhibited cleavage of C3 by the classical-pathway C3 convertase. The inhibition varied in a concn-dependent relationship, with a concn of approximately 40 micrograms/ml yielding 50% inhibition. Removal of the carboxy terminal arginine from the C3a did not alter the inhibition. C3a did not inhibit cleavage of C3 by the alternative C pathway C3 convertase, or cleavage of C5 by C5 convertase. The C3-cleaving capacity of EAC142oxy that had been previously incubated with C3a could be recovered completely by washing the cells, indicating that the C3a binding to the EAC42oxy cell must have been reversed without having had an effect on the amount of C2 bound. Ribonuclease, a molecule of similar size and charge to C3a, did not affect C3 cleavage and C3a inhibition was not reduced by providing a surface for non-specific adsorption of the C3a, suggesting that the effect of C3a on C3 cleavage was not mediated by non-specific interaction with cell surfaces. C3a inhibited the C3-cleaving capacity of the fluid-phase enzyme, C42oxy, to the same degree as it inhibited the cell-bound enzyme, EAC42oxy, indicating that the C3a must interact with the C42 complex directly. Inhibition of C3 cleavage by C3a is the first demonstration of product inhibition of a complement enzyme. It may provide another control of C3 activation.     

Serum C-Reactive Protein and Complement Proteins in Patients with Acute Myocardial Infarction

C-reactive protein (CRP) and complement proteins levels were determined in 20 patients with acute myocardial infarction (AMI) and 20 controls. Blood was obtained from all subjects at admission, 6 hr and 12 hr later. Serum CRP levels were determined by ELISA and complement proteins by radial immunodiffusion. A statistically significant elevation of the mean CRP level was obtained at 12 hr postadmission. The mean complement proteins levels were 16–49% higher in AMI patients than the controls. It appeared that the alternate pathway was activated initially, followed by activation of the classical pathway. The increased levels of CRP and complement proteins are suggestive of their involvement in AMI.     

Serum C-reactive protein and complement proteins in patients with acute myocardial infarction

C-reactive protein (CRP) and complement proteins levels were determined in 20 patients with acute myocardial infarction (AMI) and 20 controls. Blood was obtained from all subjects at admission, 6 hr and 12 hr later. Serum CRP levels were determined by ELISA and complement proteins by radial immunodiffusion. A statistically significant elevation of the mean CRP level was obtained at 12 hr postadmission. The mean complement proteins levels were 16-49% higher in AMI patients than the controls. It appeared that the alternate pathway was activated initially, followed by activation of the classical pathway. The increased levels of CRP and complement proteins are suggestive of their involvement in AMI.     

Consumption of C4b-binding protein (C4BP) during in vivo activation of the classical complement pathway.

C4BP has a central role in regulating the classical complement (C') pathway, but it is still uncertain whether or not it is consumed during in vivo complement activation. Attempts to demonstrate changes in C4BP plasma levels in systemic lupus erythematosus and essential mixed cryoglobulinaemia have failed, probably due to up-regulation of this protein during the inflammatory reaction. We have studied one patient with severe post-transfusion complement-mediated anaphylaxis (CMA), and 67 patients with hereditary C1 inhibitor deficiency (hereditary angioedema (HAE)). The first of these two conditions is characterized by the absence of systemic inflammatory reaction and the second by acute and chronic activation of the C' classical pathway. C4BP, C4BP-C4b complex, and soluble terminal C' complex (sC5b-9) were measured in the patients' plasmas by ELISA techniques and C3a and C4a by radioimmunoassays. In CMA, 15 min after the transfusion, there was a massive C' activation, with increases in C4a, C3a, sC5b-9, C4BP-C4b complexes and decreases in C4, C3 and C4BP. All parameters reverted to preinfusion values within 24 h. Depletion of C4 was correlated with that of C4BP. In patients with HAE, the median value of C4BP (83% range 54-165) was significantly lower (P < 0.0001) than in normal controls (99% range 70-159), with no difference between patients in remission or during acute attacks. C4BP-C4b complexes could not be detected in HAE patients. The results of this study indicate that C4BP is consumed in vivo during acute, and possibly during chronic activation of the C' classical pathway, and that this protein, after interaction with C4b, not longer circulates in plasma.     

丙型肝炎病毒抗体阳性人群中抗-HCV、HCV-cAg与HCV-RNA结果的相关性及其联合检测在临床应用价值的评估

目的探讨丙型肝炎病毒抗体阳性人群中抗-HCV、HCV-cAg与HCV-RNA结果的相关性及其联合检测在临床应用的价值,同时界定雅培I2000全自动化学发光仪检测抗-HCV真阳性95%时标本S/CO值的临界点。方法选取全自动化学发光仪检测的抗-HCV阳性血清样本179例(包括11例灰区标本),利用化学发光法检测HCV-cAg,利用RT-PCR法检测HCV-RNA,采用SPSS16.0软件对抗-HCVS/CO值绘制受试者操作特性(ROC)曲线,得到95%真阳性时抗-HCV结果的临界值(S/CO)。再对抗-HCV、HCV-cAg与HCV-RNA进行相关性分析。结果对179例样本进行抗-HCV、HCV-RNA及HCV-cAg的检测,其中HCV-RNA阳性43例,HCV-cAg阳性42例。在43例HCV-RNA阳性的标本中,抗-HCV的阳性检出率为93.02%,HCV-cAg阳性检出率为95.35%。抗-HCV灵敏度为93.02%,特异性为5.88%;HCV-cAg灵敏度为95.35%,特异性为99.26%。且HCV-cAg及抗-HCV阳性率随着HCV病毒含量升高而增高,RNA病毒含量越高,HCV-cAg及抗-HCV的阳性率也越高,差异具有统计学意义(P<0.05)。HCV-cAg联合抗-HCV检测与HCV-RNA的阳性符合率为100%,高于单独检测HCV-cAg或抗-HCV的阳性符合率95.35%、93.02%。以HCV-RNA检测为金标准,当抗-HCV的S/CO值>4.42时,真阳性率可达到95%。结论HCV-cAg与HCV-RNA检测的阳性符合率高达95.35%,故HCV-cAg可作为丙型肝炎早期诊断的特异性指标。为保证标本真阳性率达到95%,建议使用美国雅培I2000仪器进行丙肝抗体检测时,若抗-HCV结果(S/CO)小于4.42的标本,抗-HCV、HCV-cAg与HCV-RNA联合检测可有效降低丙型肝炎窗口期的漏检率,为丙型肝炎的早期发现、早期诊断、早期治疗提供有力证据。     

Genetic detection of the silent allele (*Q0) in hereditary deficiencies of the human complement C6, C7, and C9 components

DNA polymorphisms (RFLPs) of the human complement component C6, C7, and C9 genes were studied in three C7-deficient (C7D) families, one C6-deficient (C6D) family, and one C9-deficient (C9D) family. The 3 loci are closely linked on human chromosome 5. The haplotypes carrying the “silent” allele (C7*Q0, C6*Q0, and C9*Q0) were defined in each family, allowing for the detection of carriers among asymptomatic relatives. This paper describes familial studies on a type of hereditary trait, characterized by recurrent Neisseria infections in individuals homozygous for “silent” alleles at the C6, C7, or C9 loci. © 1995 Wiley-Liss, Inc.     

Heterosexual transmission of hepatitis C in Italy

Data from a surveillance system for type-specific acute viral hepatitis in Italy has been used to evaluate the risk of heterosexual transmission of hepatitis C virus (HCV) associated with sexual activity with multiple partners in subjects ⩾15 years of age. Hepatitis A cases were used as controls. During the period 1991–1996, 1,359 acute hepatitis C and 4,365 hepatitis A cases were recorded among subjects ⩾15 years of age. Intravenous drug use was the most frequent source of infection (35.9%) reported by HCV cases; two or more sexual partners during the 6 months before disease onset accounted for 34.9% of hepatitis C cases. Adjusting by multiple logistic regression analysis for the confounding effect of all risk factors considered (blood transfusion, intravenous drug use, surgical intervention, dental therapy, other parenteral exposure), and for age, sex, area of residence, and educational level of subjects, showed that having two or more sexual partners is an independent predictor of the likelihood of hepatitis C (OR = 2.2; 95% CI = 1.7–2.7). After excluding intravenous drug users and patients transfused with blood from analysis, the increase in the adjusted OR for the association between HCV and the number of sexual partners correlated with the increase in the number of sexual partners. The risk of hepatitis C was 2.0 times higher (95% CI = 1.4–2.9) for subjects with two sexual partners and 2.8 times higher (95% CI = 2.1–3.8) for subjects with three or more sexual partners, as compared to subjects with less than two sexual partners. These findings suggest that heterosexual transmission may play an important role in the spread of hepatitis C in Italy. J. Med. Virol. 57:111–113, 1999. © 1999 Wiley-Liss, Inc.     

Importance of sexual transmission of hepatitis C virus in seropositive pregnant women: A case-control study

The mode of hepatitis C virus (HCV) transmission in patients who deny parenteral exposure is still not understood. Seroprevalence studies of anti-HCV in sexually promiscuous populations and in spouses of infected patients have given contradictory results. We investigated the role of sexual transmission of HCV in a case-control study of risk factors for infection in a series of 43 anti-HCV positive pregnant women and 172 matched controls (4 for each case). In the univariate analysis, the following factors were associated significantly with anti-HCV seropositivity: low social class, unmarried, history of abortion, wounds which were sutured, tattooes, sharing toiletries with the partner, sexual contact outside the partnership without condom use, blood transfusion, and intravenous drug abuse, but only the last 3 factors remained significantly associated with HCV infection in multiple logistic regression analysis. The relative risk of HCV infection increased according to the increased number of sexual partners. Thus sexual transmission must be considered a possible mode of infection in HCV infected persons without parenteral exposures. J. Med. Virol. 52:164–167, 1997. © 1997 Wiley-Liss, Inc.     

Hepatitis C virus-core and non structural proteins lead to different effects on cellular antioxidant defenses

Chronic hepatitis C virus (HCV) infection leads to increased oxidative stress in the liver. Hepatic antioxidant enzymes provide an important line of defense against oxidative injury. To understand the antioxidant responses of hepatocytes to different HCV proteins, we compared changes in antioxidative enzymes in HCV-core and HCV-nonstructural protein expressing hepatocyte cell lines. We found that expression of HCV-core protein in hepatocyte cell lines leads to increased oxidative stress as determined by increased in the oxidant-sensitive probe 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-DCFH(2)) fluorescence, decreased reduced glutathione (GSH), and increased oxidation of thioredoxin (Trx). Although the expression of HCV-nonstructural (HCV-NS) proteins led to increased oxidative stress as well, the antioxidant enzymatic responses were different. Over-expression of HCV-NS proteins increased antioxidant enzymes (MnSOD and catalase), heme oxygenase-1 (HO-1), and GSH, indicating different mechanism(s) of prooxidative activity than HCV-core protein. Our findings show that different HCV proteins induce different antioxidant defense responses in hepatocytes. These findings may facilitate understanding the interaction of different HCV proteins with infected liver cells and help identify possible factors contributing to hepatocyte damage during HCV infection.     

Hepatitis C virus infection in 2,744 hemodialysis patients followed regularly at nine centers in Hiroshima during November 1999 through February 2003

Patients on maintenance hemodialysis (HD) are at increased risk of infection with hepatitis C virus (HCV). A prospective follow-up study on HCV infection from November 1999 to February 2003 was conducted in nine hemodialysis (HD) units in Hiroshima. A total of 2,744 HD patients were surveyed regularly for HCV RNA in serum. The prevalence of HCV RNA decreased from 15.7% (262/1,664) on the first survey to 12.9% (242/1,882) in the last one (P<0.05). This decrease may be attributed to the inclusion of patients with a lower prevalence of HCV RNA compared to patients leaving dialysis centers (111/1,080 [10.3%] vs. 132/862 [15.3%], P<0.01). During the 40 months of this study, 16 de novo HCV infections were documented in the nine HD units corresponding to an incidence of 0.33% per year. These cases included eight new HCV infections, three re-infections, and five infections that presumably occured in the window period when tested during the first survey. Our study shows that the annual incidence of de novo HCV infection during HD was 0.33%, and emphasizes the need for frequent serum HCV RNA testing and for stringent disinfection procedures in order to prevent the transmission of HCV in these settings.     

丙型肝炎病毒核心基因重组腺病毒的构建、鉴定与表达

目的构建HCV C基因重组腺病毒，以期用于HCV C蛋白的功能研究。方法以含有丙肝病毒1b亚型核心基因的质粒pcDNA3.1／HCV-C为模板，PCR扩增HCV C基因，PCR产物双酶切后亚克隆至穿梭质粒pAdTrack-CMV上，与骨架质粒pAdEasy-1在BJ5183细菌内同源重组，获得重组腺病毒质粒pAd-C，PacⅠ酶切线性化后脂质体法转染293细胞进行包装，获得重组腺病毒Ad-C，继之在293细胞内扩增，利用报告基因GFP监测病毒滴度和感染效率，Western blot检测HCV C蛋白的表达。结果PCR及Western blot结果均证实重组腺病毒Ad-C构建成功。结论成功构建了重组腺病毒Ad-C，为进一步研究核心蛋白的生物学功能奠定了基础。     

丙型肝炎病毒核心抗原检测用于献血者筛查价值的探讨

目的应用酶联免疫吸附技术筛查献血员中丙型肝炎病毒核心抗原（HCV—cAg）和抗体（HCV—Ab），了解丙型肝炎病毒核心抗原筛查献血员应用价值。方法对我站2004年8-12月间的3972份献血者血清标本进行抗-HCV初、复检和HCV—cAg ELISA检测，将ELISA法阳性的25份血清标本，再做RT-PCR检测证实。结果3972份血清标本检测中，有10份仅初检抗-HCV阳性样本，经HCVRNA检测阳性有l份，12份仅复检抗-HCV阳性样本，经HCVRNA检测阳性有1份，HCV—cAg检测阳性有3份，经HCVRNA检测阳性有2份。结论HCV—cAg ELISA检测技术的敏感性与HCVRNA技术类似，但成本明显降低，可与HCV抗体联合检测应用献血员筛查。     

Changes in Hepatitis C Virus Genotype Distribution in Chronic Hepatitis C Infection Patients

Purpose: Identification of hepatitis C virus (HCV) genotypes is very important in the selection of antiviral treatment, dose adjustment of antiviral agents, determining the treatment duration and following-up of treatment response. We aimed to determine the distribution pattern of HCV genotypes in chronic hepatitis C infection (CHC) patients. Materials and Methods: We have included 106 CHC patients who were positive in the anti-HCV and HCV-RNA tests performed in our hospital during the 16-month period. Anti-HCV assays were performed on device using a chemiluminescent microparticle immunoassay, while HCV-RNA tests and HCV genotyping assays were performed by real-time polymerase chain reaction. Results: Of the 106 cases; genotype 1b was detected in 67.0%, genotype 3 was detected in 16.0%, genotype 1a was detected in 14.2% and genotype 2 was detected in 2.8% patients. Genotypes 4, 5 and 6 were not detected in our study group. There were no statistically significant differences between the gender and age groups according to the HCV genotype distribution. The genotype 3 detection rate (16%) was the highest rate among the studies compared with the other studies in our country. Conclusions: Events that cause social changes such as war and immigration and intense commercial and touristic activities affect and alter the HCV genotype distribution in HCV-infected patients. For this reason, further multicentre studies are required reflecting all the regions in order to determine the genotype distribution in HCV-infected patients at regular intervals.     

13C呼气试验-一种非侵入的临床检测方法

活体评估不同代谢途径的安全性问题一直是其临床应用推广的重大阻碍，而稳定同位素呼气试验却巧妙地避开了这个问题，自上个世纪七十年代诞生以来，在某些领域迅速完成从科研到临床的过渡。近年来，质谱仪推广的同时，新型底物和测试餐的发掘逐渐深入，稳定核素13C呼气试验逐渐被用于药物代谢学、营养学以及消化系统各种疾病的诊断研究中。本文旨在讲述13C呼气试验作为一种非侵入性的检测方法在临床中的应用进展。     

豚鼠血清功能纯C2分子的制备和鉴定

以低渗沉淀方法制备的豚鼠血清功能纯Ｃ１及人血清为实验材料，建立Ｃ２溶血活性检测方法，经ＣＭ－ＳｅｐｈａｄｅｘＣ５０离子交换色谱分离纯化豚鼠血清功能纯Ｃ２分子。经鉴定，所得功能纯Ｃ２具有良好活性，无Ｃ１及Ｃ３～Ｃ９活性成份，可用于体外组装经典途径Ｃ３转化酶。本工作为进一步研究经典途径Ｃ３转化酶的补体调控蛋白奠定了基础。     

13C呼气试验检测肝脏线粒体功能

肝脏是体内最大的器官，其中的代谢活动十分复杂。肝病作为一种严重的常见多发病，严重威胁着患者的身体健康。及时、准确地了解肝脏功能具有重要的临床意义。目前临床上仍然缺乏安全、简便、准确、重复性佳的肝功能检测手段。传统肝脏功能血清学检查以及现有的定量肝功能动态试验，如动脉血酮体比（artery ketone body ratio，AKBR）测定、     

Functions of C5a receptors

The split product of the complement protein, C5, is C5a and is an extremely potent pro-inflammatory peptide that interacts with two C5a receptors, C5aR and C5L2, present on surfaces of phagocytes as well as other cell types. The former is a well-established receptor that initiates G-protein-coupled signaling via mitogen-activated protein kinase pathways. Its in vivo blockade greatly reduces inflammatory injury. Much less is known about C5L2, occupancy of which by C5a does not initiate increased intracellular Ca²⁺. There are numerous conflicting reports suggesting that C5L2 is a “default receptor” that attenuates C5a-dependent biological responses by competing with C5aR for binding of C5a. However, there are other reports suggesting that C5L2 plays an active, positive role in inflammatory responses. Better definition of C5L2 is needed if its in vivo blockade, along with C5aR, is to be considered in complement-dependent inflammatory diseases.     

氨基比林呼气试验的临床应用现状和问题

13C呼气试验检测肝脏储备功能在短时间内得到研究者的认同，这不仅因为其非侵害性，更是由于从某种程度上它具有较高的灵敏度、特异度以及简便、可重复的特性。相比于传统的血清学检查和定量肝功能动态检查，临床上的肝储备功能定量检测更倾向于采用这种安全无创的手段。