Inhibition of hepatitis B virus DNA replicative intermediate forms by recombinant interferon-γ

AIM: To evaluate the in vitro anti-HBV activity of recombinant human IFN-γ, alone and in combination with lamivudine. METHODS: A recombinant baculovirus-HBV/HepG2 culture system was developed which could support productive HBV infection in vitro. Expression of HBsAg and HBeAg in infected HepG2 culture medium was detected by commercial enzyme immunoassays. HBV DNA replication intermediates were detected in infected cells by Southern hybridization and viral DNA load was determined by dot hybridization. RESULTS: IFN-γat 0.1 to 5μg/L efficiently down regulated HBsAg expression in transduced HepG2 cells. At 5μg/L, IFN-γalso suppressed HBV DNA replication in these cells. While treatment with a combination of lamivudine and IFN-γshowed no additive effect, sequential treatment first with lamivudine and then IFN-γwas found to be promising. In this culture system the best HBV suppression was observed with a pulse of 2μmol/L lamivudine for two days, followed by 1μg/L IFN-γfor another four days. Compared to treatment with lamivudine alone, the sequential use of 0.2μmol/L lamivudine for two days, followed by 5μg/L IFN-γfor six days showed a 72% reduction in HBV cccDNA pool. CONCLUSION: This in vitro study warrants further evaluation of a combination of IFN-γand lamivudine, especially in IFN-αnon-responder chronic hepatitis B patients. A reduced duration of lamivudine treatment would also restrict the emergence of drug-resistant HBV mutants.     

Diagnosis of fetal rubella infection by nucleic acid hybridization

The efficacy of nucleic acid hybridization for the diagnosis of rubella infection in experimental and clinical materials was compared with immunoblot and virus isolation techniques. Our results showed that nucleic acid hybridization is specific and rapid but gives false-negative results when compared with conventional virus isolation in some experimental although not in clinical materials so far examined. For this reason, a failure to demonstrate rubella virus in fetal specimens by this method alone cannot yet be taken as a sole criterion for ruling out fetal rubella infection.     

肝癌及癌旁组织中丙型肝炎病毒基因负链的研究

运用巢式聚合酶链反应（ＰＣＲ）等方法检测了５例丙型肝炎病毒核糖核酸（ＨＣＶ—ＲＮＡ）阳性患者的肝癌、癌旁组织和周围血清中ＨＣＶ—ＲＮＡ正链和负链，其中男４例，女１例。结果，正链检测：血清及癌旁组织全部阳性，癌组织中３例阳性。负链检测：血清中均阴性，癌组织３例阳性，癌旁组织５例均阳性。本组５例患者肝脏ＨＣＶ—ＲＮＡ负链阳性，推测ＨＣＶ以ＨＣＶ—ＲＮＡ负链作为模板在感染的肝脏组织中复制，ＨＣＶ持续存在于肝脏组织中对肝癌的发生起了一定的作用。     

流行性出血热病毒感染黑线姬鼠有效剂量的观察

用Hantaan病毒(76-118株)悬液以不同感染剂量采用灌胃和浸泡毒米任实验鼠自行取食两种方法,对捕自非疫区的黑线姬鼠进行实验感染。结果表明:实验鼠未能通过完整的消化道粘膜感染,但可通过破损的消化道粘膜感染,感染剂量与感染率呈正相关,最低感染剂量为10ID_(so)/ml。     

dC14可抑制小鼠SRS腹水瘤的发病和生长

作者曾经体外实验证明,均聚寡脱氧胞嘧啶核苷酸片段(dC14)有抗病毒活性,现继续研究其在体内的作用。不给dC14的对照组小鼠,接种腹水瘤细胞后:100％发病和死亡,潜伏期为6d,存活期11d;给每只小鼠dC14 1.3～3.2 mg,发病率和死亡率降低至20％,疾病潜伏期和存活期推迟。在未经dC14处理的种瘤细胞和淋巴组织与经处理的淋巴组织中,多聚酶链反应(PCR)法都检测到病毒核酸,而正常小鼠中则无此种病毒核酸顺序。研究结果提示,dC14对小鼠SRS腹水瘤的发病和生长有抑制作用。此种抑制作用可能是通过抑制病毒基因的表达来实现的。     

甲型流感病毒治疗S37腹水瘤小鼠的实验研究

甲型流流感病毒鼠肺适庆型７５－３９株治疗Ｓ３７腹水型荷瘤小鼠，存活率达９３．３％。体外实验观察流感病毒感染Ｓ３７肿瘤细胞，到３天时Ｓ３７细胞经胎盘蓝染色，１００％的Ｓ３７细胞死亡，而对照组肿瘤细胞染色率只有１０％左右。     

Autopsy findings in two cases of neonatal herpes simplex virus infection: detection of virus by immunohistochemistry, in situ hybridization and the polymerase chain reaction

We describe the pathological findings in two fatal cases of neonatal infection with herpes simplex virus. One had an encephalitis caused by herpes simplex virus type 2 (HSV-2); the other had a disseminated infection with herpes simplex virus type 1 (HSV-1). Confirmation of the diagnosis was obtained by use of the polymerase chain reaction to amplify viral DNA from paraffin sections of autopsy tissues. By using primers which amplify fragments of the HSV-1 thymidine kinase gene and HSV-2 glycoprotein gene respectively it was possible to discriminate between infection with HSV-1 and HSV-2. In contrast, immunohistochemistry and in situ hybridization using commercially available reagents did not distinguish between HSV-1 and HSV-2 infection. However, immunohistochemistry and in situ hybridization are probably more reliable than the polymerase chain reaction for assessment of the distribution of virus in different tissues.     

Human spumaretrovirus antibody reactivity in multiple sclerosis

The role of human spumaretrovirus (HSRV) infections in the pathogenesis of multiple sclerosis (MS) was investigated with recombinant HSRV env-specific enzyme-linked immunosorbent assay. The presence of HSRV antibodies was determined in pairs of serum and cerebrospinal fluid (CSF) samples from 60 MS patients. In 7 of these patients serial serum and CSF samples were obtained in relation to the clinical activity of the disease during a period of 2 years. No increased antibody reactivity was demonstrable in the MS population compared with 14 aseptic meningitis patients, 50 blood donors and 16 healthy controls. Slightly elevated levels of antibodies were demonstrable in serum and/or CSF in 4 MS patients but also in 1 patient with aseptic meningitis, 1 blood donor and 1 child. No marked serum or CSF HSRV antibody fluctuation was observed in the MS patients followed longitudinally. Thus, this study does not support the involvement of HSRV in the pathogenesis of MS.     

丁型肝炎病毒中国SZ株的cDNA克隆及基因变异分析

以四川地区１例无症状携带丁型肝炎病毒（ＨＤＶ）和乙型肝炎病毒（ＨＢＶ）患者的外周血为标本，采用逆转录－ＰＣＲ技术，获得了ＨＤＶ全基因组的ｃＤＮＡ克隆（ＨＤＶＳＺ９３株），全长１６８４ｂｐ。与世界其他七个地区株相比，其核酸同源性为８１．８％～９５．４％；丁肝病毒抗原蛋白编码区核酸同源性为８８．９％～９６．１％，氨基酸同源性为８６，４％～９３．０％。另从１例慢性重型肝炎患者血清内克隆了丁肝病毒抗原蛋白（ＨＤＡｇ）编码基因（ＨＤＶ－ＳＺ９２株），与ＳＺ９３株相比，亦存在若干变异。对这些不同地区、不同病情ＨＤＶ株变异的可能意义进行了讨论。     

青天葵抗甲、乙型流感病毒作用研究

目的研究青天葵在体外抗甲、乙型流感病毒株作用。方法选用狗肾细胞培养法考察青天葵不同极性部位对甲型(FM1)、乙型(昆40B)流感病毒的作用。结果青天葵水溶性部位对甲型流感病毒FM1有抑制作用。结论青天葵具有体外抗甲型流感病毒作用。