鸭病毒性肝炎的诊治

２０００年５月上旬，郑州市郊古荥镇养鸭专业户雏鸭暴发死亡，以全身性抽搐，两腿痉挛向后踢，头向后背死亡为特征的传染病，送我室化验诊治，经诊断为鸭病毒性肝炎，现将情况报告如下。１　　发病情况２０００年５月上旬，郑州市郊古荥镇几十个养鸭专业户雏鸭发生大批死亡，该批鸭苗从长葛市、荥阳市鸭厂购进，以２周龄内的雏鸭死亡率最高，个别养鸭户鸭死亡率达８０％以上。现场观察，养鸭户大多以庭养为主，鸭舍卫生极差，发病后，个别养鸭户用恩诺沙星饮水治疗未能控制疫情。２　　临床症状及病理变化病鸭主要表现为精神萎顿，缩颈，头…     

Regulation of interferon regulatory factor-3 by the hepatitis C virus serine protease

Persistent infections with hepatitis C virus (HCV) are likely to depend on viral inhibition of host defenses. We show that the HCV NS3/4A serine protease blocks the phosphorylation and effector action of interferon regulatory factor-3 (IRF-3), a key cellular antiviral signaling molecule. Disruption of NS3/4A protease function by mutation or a ketoamide peptidomimetic inhibitor relieved this blockade and restored IRF-3 phosphorylation after cellular challenge with an unrelated virus. Furthermore, dominant-negative or constitutively active IRF-3 mutants, respectively, enhanced or suppressed HCV RNA replication in hepatoma cells. Thus, the NS3/4A protease represents a dual therapeutic target, the inhibition of which may both block viral replication and restore IRF-3 control of HCV infection.     

Modulation of hepatitis C virus RNA abundance by a liver-specific MicroRNA

MicroRNAs are small RNA molecules that regulate messenger RNA (mRNA) expression. MicroRNA 122 (miR-122) is specifically expressed and highly abundant in the human liver. We show that the sequestration of miR-122 in liver cells results in marked loss of autonomously replicating hepatitis C viral RNAs. A genetic interaction between miR-122 and the 5' noncoding region of the viral genome was revealed by mutational analyses of the predicted microRNA binding site and ectopic expression of miR-122 molecules containing compensatory mutations. Studies with replication-defective RNAs suggested that miR-122 did not detectably affect mRNA translation or RNA stability. Therefore, miR-122 is likely to facilitate replication of the viral RNA, suggesting that miR-122 may present a target for antiviral intervention.     

病毒性肝炎患者血清微量元素的检测及其临床意义

目的:探讨病毒性肝炎患者和肝炎肝硬化患者血清微量元素水平与病情的相关性。方法:采用RI- 10 0 0 TM全自动生化分析仪检测2 73例病毒性肝炎患者(慢性肝炎130例、急性肝炎35例、重型肝炎38例、肝炎肝硬化70例)及4 0例正常对照者血清中镁、铁、铜、锌的水平。结果:各型肝炎及肝硬化患者血清锌水平均显著低于正常对照组(P<0 .0 1)。除急性肝炎组外,慢性肝炎、重型肝炎、肝炎肝硬化患者血清中镁、铜水平均显著低于正常对照组(P<0 .0 1) ,血清中镁、铜、锌水平以重型肝炎组最低。各型肝炎及肝硬化患者血清铁水平均显著高于正常对照(P<0 .0 1) ,以重型肝炎组最高。结论:检测病毒性肝炎患者血清中的微量元素,对了解病情及指导临床治疗具有一定的意义。     

Spring-loaded mechanism of DNA unwinding by hepatitis C virus NS3 helicase

NS3, an essential helicase for replication of hepatitis C virus, is a model enzyme for investigating helicase function. Using single-molecule fluorescence analysis, we showed that NS3 unwinds DNA in discrete steps of about three base pairs (bp). Dwell time analysis indicated that about three hidden steps are required before a 3-bp step is taken. Taking into account the available structural data, we propose a spring-loaded mechanism in which several steps of one nucleotide per adenosine triphosphate molecule accumulate tension on the protein-DNA complex, which is relieved periodically via a burst of 3-bp unwinding. NS3 appears to shelter the displaced strand during unwinding, and, upon encountering a barrier or after unwinding >18 bp, it snaps or slips backward rapidly and repeats unwinding many times in succession. Such repetitive unwinding behavior over a short stretch of duplex may help to keep secondary structures resolved during viral genome replication.     

几种提纯鸭病毒性肝炎血清免疫球蛋白G方法的比较

用辛酸-硫酸铵法、硫酸铵法、硫酸钠法和聚乙二醇沉淀法分别提纯鸭抗DHV血清中免疫球蛋白G(IgG),经SDS-PAGE电泳、蛋白含量及生物活性测定分析表明,先用辛酸澄清,再用50%饱和硫酸铵粗提,最后用35%饱和硫酸铵重复两次提取的IgG纯度和生物活性均较其它方法高。此法操作简便,便于推广应用。     

鸭病毒性肝炎病原分离与鉴定

从郑州地区疑似鸭病毒性肝炎的病例中分离到1株病毒，该病毒可使7日龄健康鸭100％发病，90％死亡，死亡鸭具有鸭病毒性肝炎的典型病变，经血清学试验鉴定该病毒为Ⅰ型鸭肝炎病毒。     

鸭病毒性肝炎多价卵黄抗体的研制

选取4株不同地区分离的适应鸡胚的鸭肝炎病毒作为疫苗株制备灭活苗,免疫试验鸡制备卵黄抗体。鸡胚中和试验表明,第三次免疫后15天,抗体中和效价(PD50)都在29以上,卵黄抗体保护雏鸭试验显示,本试验制备的卵黄抗体有着显著的预防效果,并大大提高攻毒后雏鸭的存活率。     

Single-base pair unwinding and asynchronous RNA release by the hepatitis C virus NS3 helicase

Nonhexameric helicases use adenosine triphosphate (ATP) to unzip base pairs in double-stranded nucleic acids (dsNAs). Studies have suggested that these helicases unzip dsNAs in single-base pair increments, consuming one ATP molecule per base pair, but direct evidence for this mechanism is lacking. We used optical tweezers to follow the unwinding of double-stranded RNA by the hepatitis C virus NS3 helicase. Single-base pair steps by NS3 were observed, along with nascent nucleotide release that was asynchronous with base pair opening. Asynchronous release of nascent nucleotides rationalizes various observations of its dsNA unwinding and may be used to coordinate the translocation speed of NS3 along the RNA during viral replication.     

Complete replication of hepatitis C virus in cell culture

Many aspects of the hepatitis C virus (HCV) life cycle have not been reproduced in cell culture, which has slowed research progress on this important human pathogen. Here, we describe a full-length HCV genome that replicates and produces virus particles that are infectious in cell culture (HCVcc). Replication of HCVcc was robust, producing nearly 10(5) infectious units per milliliter within 48 hours. Virus particles were filterable and neutralized with a monoclonal antibody against the viral glycoprotein E2. Viral entry was dependent on cellular expression of a putative HCV receptor, CD81. HCVcc replication was inhibited by interferon-alpha and by several HCV-specific antiviral compounds, suggesting that this in vitro system will aid in the search for improved antivirals.     

Isolation of a cDNA clone derived from a blood-borne non-A, non-B viral hepatitis genome

A random-primed complementary DNA library was constructed from plasma containing the uncharacterized non-A, non-B hepatitis (NANBH) agent and screened with serum from a patient diagnosed with NANBH. A complementary DNA clone was isolated that was shown to encode an antigen associated specifically with NANBH infections. This clone is not derived from host DNA but from an RNA molecule present in NANBH infections that consists of at least 10,000 nucleotides and that is positive-stranded with respect to the encoded NANBH antigen. These data indicate that this clone is derived from the genome of the NANBH agent and are consistent with the agent being similar to the togaviridae or flaviviridae. This molecular approach should be of great value in the isolation and characterization of other unidentified infectious agents.     

The early evolution of the tetrapod humerus

A tetrapod humerus from the Late Devonian of Pennsylvania has a novel mix of primitive and derived characters. A comparative analysis of this fossil and other relevant humeri from the Devonian shows that the role of the limb in propping the body arose first in fish fins, not tetrapod limbs. The functional diversity of the earliest known limbs includes several different kinds of appendage design. This functional diversity was achieved with a humeral architecture that was remarkably conserved during the Devonian.     

The geological evolution of the Tibetan Plateau

The geological evolution of the Tibetan plateau is best viewed in a context broader than the India-Eurasia collision zone. After collision about 50 million years ago, crust was shortened in western and central Tibet, while large fragments of lithosphere moved from the collision zone toward areas of trench rollback in the western Pacific and Indonesia. Cessation of rapid Pacific trench migration ( approximately 15 to 20 million years ago) coincided with a slowing of fragment extrusion beyond the plateau and probably contributed to the onset of rapid surface uplift and crustal thickening in eastern Tibet. The latter appear to result from rapid eastward flow of the deep crust, probably within crustal channels imaged seismically beneath eastern Tibet. These events mark a transition to the modern structural system that currently accommodates deformation within Tibet.     

The predicted structure of immunoglobulin D1.3 and its comparison with the crystal structure

Predictions of the structures of the antigen-binding domains of an antibody, recorded before its experimental structure determination and tested subsequently, were based on comparative analysis of known antibody structures or on conformational energy calculations. The framework, the relative positions of the hypervariable regions, and the folds of four of the hypervariable loops were predicted correctly. This portion includes all residues in contact with the antigen, in this case hen egg white lysozyme, implying that the main chain conformation of the antibody combining site does not change upon ligation. The conformations of three residues in each of the other two hypervariable loops are different in the predicted models and the experimental structure.     

Inhibition of chemical carcinogenesis by viral vaccines

The incidence of 3-methylcholanthrene-induced subcutaneous tumors was significantly reduced by a single injection of inactivated type C RNA viral vaccine. Rauscher leukemia virus vaccine reduced the incidence of sarcomas from 78 to 50 percent in the BALB/cCr mouse. Radiation leukemia virus vaccine and a vaccine from a wild murine leukemia virus derived from a 3-methylcholanthrene tumor reduced the incidence of sarcoma from 86 percent to 33 and 37 percents, respectively, in the C57BL/6 mouse. These reductions in tumor incidence by virus vaccines help support the concept that type C RNA viruses serve as determinants of chemically induced cancer; additional studies of vaccines made with more purified virus preparations are necessary.