Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular basis for the variation in induction of monocyte procoagulant activity (PCA) by murine hepatitis virus strain 3 (MHV-3) was examined using a set of recombinant inbred strains of mice derived from the resistant (A/J) and susceptible C57B1/6J (B) progenitors. Induction of PCA by MHV-3 required live virus and host protein and RNA synthesis. Absolute restriction for induction of PCA was observed at the level of the macrophage. Peritoneal macrophages from resistant parental A/J and RI strains (AXB5) could not be induced to express PCA when stimulated by MHV-3 alone or in the presence of lymphocytes from susceptible and H-2 compatible RI mice (AXB3) although they did respond to endotoxin (LPS). In contrast, macrophages from both susceptible (AXB3) and semisusceptible (AXB1) RI strains of mice expressed a similar increase in PCA after stimulation with MHV-3 in the absence of lymphocytes. The levels of PCA expressed by macrophages in the presence of Thy-1.2+ lymphocytes correlated with susceptibility to disease. Thy-1.2+ lymphocytes from susceptible RI AXB3 mice could induce levels of PCA in macrophages from semisusceptible RI AXB1 mice equivalent to that seen in cultures of macrophages and lymphocytes from susceptible mice. Further subfractionation of Thy-1.2+ cells demonstrated that L3T4+ cells instructed macrophages to produce PCA. Thy-1.2+ cells from MHV-3 immunized resistant AXB5 mice, but not from non-immunized mice, were able to suppress induction of PCA. This suppressor cell activity could be detected 4 days after immunization, reaching maximal activity at day 7 with significant suppression even at 28 days. The PCA was shown to have direct prothrombin cleaving activity (prothrombinase) by ELISA and immunofluorescence staining using the mAb 3D4.3. These results demonstrate that induction of a unique PCA (prothrombinase) is restricted at the level of the macrophage and define a regulatory role for T lymphocytes in its induction.
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PMID:Cellular and metabolic requirements for induction of macrophage procoagulant activity by murine hepatitis virus strain 3 in vitro. 170 94

A panel of 24 IgG2ak monoclonal antibodies was produced against murine hepatitis virus strain 3 (MHV-3)-induced procoagulant activity (PCA) from murine macrophages. The antibodies were specific and did not react in an enzyme-linked immunosorbent assay with purified MHV-3; lipopolysaccharide-induced PCA; crude mouse, human, or rabbit tissue factor, or unstimulated murine macrophages. Sixteen of 24 monoclonal antibodies inhibited functional PCA expression in a one-stage clotting assay. More detailed studies on one monoclonal antibody, 3D4.3, demonstrated that it inhibited prothrombin cleavage at concentrations of greater than or equal to 0.1 microgram/ml, and by Western blot this antibody reacted with proteins of a molecular mass of 140, 74, and 70 kDa on nonreduced gels and 74 and 70 kDa on reduced gels distinct from tissue factor known to have a molecular mass of 47 kDa. Induction of PCA was dependent on both host RNA and protein synthesis. Immunofluorescence studies showed specific binding to MHV-3-stimulated PCA-positive macrophage membranes. Both numbers of positive macrophages and intensity of staining correlated with multiplicity of infection. These monoclonal antibodies will be useful in isolation and characterization of the unique viral-induced PCA as well as in determining its biologic role in MHV infection and other diseases in which the prothrombinase has been implicated.
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PMID:Monoclonal antibody analysis of a unique macrophage procoagulant activity induced by murine hepatitis virus strain 3 infection. 184 63

Previously, we demonstrated induction of a unique macrophage prothrombinase during infection of BALB/cJ mice by mouse hepatitis virus strain 3 (MHV-3). By immunologic screening, a clone representing this prothrombinase was isolated from a cDNA library and sequenced. The sequence identified this clone as representing part of a gene, musfiblp, that encodes a fibrinogen-like protein. Six additional clones were isolated, and one clone, p11-3-1, encompassed the entire coding region of musfiblp. Murine macrophages did not constitutively express musfiblp but, when infected with MHV-3, synthesized musfiblp-specific mRNA. musfiblp mRNA induction was earlier and significantly greater in BALB/cJ than A/J macrophages. Prothrombinase activity was demonstrated when musfiblp was expressed from p11-3-1 in RAW 264.7 cells. These data suggest that musfiblp encodes the MHV-induced prothrombinase.
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PMID:Association of mouse fibrinogen-like protein with murine hepatitis virus-induced prothrombinase activity. 760 73

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of anti-HCV antibody. We assayed for antibodies against either oligopeptide (S29-1) deduced from the nucleocapsid gene or the product of nonstructural region (NS3) synthesized in a recombinant Escherichia coli (S4). To reduce false-positive results induced by non-specific binding of antibodies with a carrier protein and to increase the sensitivity of an immunoassay, non-fused S4 peptide was prepared by the recombinant DNA technique and site-specific proteolysis (by factor Xa). In 71 non-A, non-B hepatitis patients with chronic liver disease, 70 (98.5%) were positive by S29-1/S4 ELISA as well as by a second-generation test (Abbott II). On the other hand, of 40 serum samples from blood donors, in which anti-N14 (core) and C100-3 antibodies were not detected but hepatitis C virus (HCV) RNA was detectable by polymerase chain reaction (PCR), 24 (60%) were positive by S29-1/S4 ELISA, whereas only 18 (45%) were diagnosed by Abbott II. In addition, based on results in a small group of 92 blood donors, detection of anti-S29-1/S4 antibody correlated well with HCV viremia as confirmed by PCR. These results indicated that the preparation of nonfused protein (S4) by recombinant DNA technique and a combination of S29-1 and S4 as immobilized antigens in an ELISA provide a sensitive and specific diagnosis for HCV infection with good correlation with the presence of viral RNA as confirmed by PCR.
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PMID:A sensitive serodiagnosis of hepatitis C virus (HCV) infection with two non-fused peptides: comparison of antibody responses detected with a newly developed assay and a commercial second-generation test. 768 47

Plasma levels of prothrombin fragment F 1 + 2 (PTF) and thrombin-antithrombin III complex (TAT) were assayed in 86 cases of disseminated intravascular coagulation (DIC). A significant elevation of both parameters was observed in most cases of DIC, which suggested that the in vivo generation of thrombin is highly accelerated by the cleavage of the prothrombin molecule by factor Xa. On the contrary, no significant elevation of plasma levels of PTF was observed in cases of DIC with severe hepatic failure or fulminant hepatitis in spite of significant elevation of TAT. Plasma levels of PTF were directly proportional to those of TAT in 86 cases of DIC as a whole (r = 0.682, p < 0.001). The measurement of both parameters was considered to be useful to estimate the hemostatic activation in DIC.
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PMID:Changes in plasma levels of prothrombin fragment F 1 + 2 in cases of disseminated intravascular coagulation. 848 Apr 81

Activation of the immune coagulation system has been implicated in the pathogenesis of liver injury following infection of inbred mice with murine hepatitis virus strain 3 (MHV-3). Following MHV-3 infection, macrophages isolated from MHV-3-susceptible and -semisusceptible inbred strains of mice express increased procoagulant activity (PCA), whereas macrophages from resistant strains express no increase in PCA over basal levels. The PCA induced by MHV-3 is a prothrombinase, encoded by the gene Fgl-2, which encodes a fibrinogen-like protein (musfiblp). In this study, MHV-3-resistant A/J mice treated with methylprednisolone prior to infection with MHV-3 developed elevated levels of alanine aminotransferase in serum and died within 10 days of infection, with histological findings of fulminant hepatitis. In vitro, macrophages isolated from A/J mice and pretreated with methylprednisolone produced a marked increase in functional PCA following infection with MHV-3. The PCA was shown to be a prothrombinase by its ability to cleave 125I-prothrombin. Northern blot analysis of RNA transcripts from these macrophages demonstrated increased transcription of the Fgl-2 gene relative to that in macrophages which had not been pretreated with methylprednisolone prior to MHV-3 infection. Methylprednisolone pretreatment of MHV-3-infected macrophages stabilized the Fgl-2 mRNA. Thus, loss of resistance to MHV-3 secondary to methylprednisolone therapy is associated with increased transcription and stability of Fgl-2 mRNA resulting in expression of the Fgl-2 gene product, musfiblp. These results provide further insight into mechanisms of PCA regulation in response to MHV-3 infection in inbred strains of mice.
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PMID:Loss of resistance to murine hepatitis virus strain 3 infection after treatment with corticosteroids is associated with induction of macrophage procoagulant activity. 867 49

BALB/cJ mice die of fulminant hepatitis within 7 days of exposure to murine hepatitis virus strain 3 (MHV-3) whereas A/J mice are fully resistant to the lethal effects of MHV-3 infection. Previous studies have implicated macrophage activation with production of a unique macrophage prothrombinase (PCA) and lymphocyte cytokine secretion in the pathogenesis of MHV-3 susceptibility and have demonstrated that immunosuppression induces susceptibility in resistant mice. This study was undertaken to determine whether macrophages, derived from resistant A/J mice and treated in vitro with methylprednisolone sodium succinate (MP), elaborated PCA following MHV-3 exposure and whether therapy with MP altered resistance of A/J mice to MHV-3 infection in vivo. Macrophages, incubated with MP in vitro, expressed dose dependent increases in PCA following infection with MHV-3. No induction of PCA occurred in macrophages treated with MHV-3 or MP alone. Analysis of mRNA transcripts for mouse fibrinogen like protein (musfiblp), the MHV-3 specific prothrombinase, in macrophages which were incubated with MP prior to exposure to MHV-3 demonstrated significantly increased mRNA levels as compared to macrophages not incubated with MP prior to MHV-3 exposure. In vivo, A/J mice treated for 3 days with 500 mg/kg/day of MP prior to infection with MHV-3 demonstrated extensive hepatocyte necrosis and fibrin deposition in hepatic sinusoids on histological examination of liver tissue, elevated serum transaminases and 100% mortality within 10 days of infection. These results therefore provide further support for the role of increased PCA in the pathogenesis of MHV-3 related liver necrosis.
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PMID:Treatment of resistant A/J mice with methylprednisolone (MP) results in loss of resistance to murine hepatitis strain 3 (MHV-3) and induction of macrophage procoagulant activity (PCA). 883 May 51

Activation of the immune coagulation system has been implicated in the pathogenesis of fulminant liver failure caused by murine hepatitis virus strain 3 (MHV-3). The recent discovery of the fgl2 gene, which encodes for MHV-3-induced prothrombinase (fgl2 prothrombinase), allows for fundamental studies to determine the molecular basis for fulminant liver failure. Transcription of the fgl2 gene and translation of the protein it encodes were examined in the liver and other organs of susceptible mice following MHV-3 infection. No constitutive expression of the fgl2 gene or the fgl2 prothrombinase was detected. Within 12 to 24 h of MHV-3 infection, however, fgl2 gene transcripts were detected in large amounts in the liver, spleen, and lungs, all of which are rich in reticuloendothelial cells, but were only focally present in small amounts in the kidney and brain. There was sequential detection of fgl2 prothrombinase in the liver, where it was localized specifically to the endothelium of intrahepatic veins and hepatic sinusoids; this was allowed by fibrin deposition, which resulted in confluent hepatocellular necrosis. These results provide further evidence for the role of the selective expression of this novel fgl2 prothrombinase in the pathogenesis of MHV-3-induced fulminant liver failure.
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PMID:Fulminant hepatic failure in murine hepatitis virus strain 3 infection: tissue-specific expression of a novel fgl2 prothrombinase. 937 81

Ribavirin, a synthetic guanosine analogue, possesses a broad spectrum of activity against DNA and RNA viruses. It has been previously shown to attenuate the course of fulminant hepatitis in mice produced by murine hepatitis virus strain 3. We therefore studied the effects of ribavirin on murine hepatitis virus strain 3 replication, macrophage production of proinflammatory mediators including TNF, IL-1, and the procoagulant activity (PCA), fgl2 prothrombinase; and Th1/Th2 cytokine production. Although ribavirin had inhibitory effects on viral replication (<1 log), even at high concentrations complete eradication of the virus was not seen. In contrast, at physiologic concentrations (up to 500 microg/ml), ribavirin markedly reduced viral-induced parameters of macrophage activation. With ribavirin treatment, the concentrations of PCA, TNF-alpha and IL-1beta all decreased to basal concentrations: PCA from 941 +/- 80 to 34 +/- 11 mU/10(6) cells; TNF-alpha from 10.73 +/- 2.15 to 2.74 +/- 0.93 ng/ml; and IL-1beta from 155.91 +/- 22.62 to 5.74 +/- 0.70 pg/ml. The inhibitory effects of ribavirin were at the level of gene transcription as evidenced by Northern analysis. Both in vitro and in vivo, ribavirin inhibited the production of IL-4 by Th2 cells, whereas it did not diminish the production of IFN-gamma in Th1 cells. In contrast, ribavirin had no inhibitory effect on TNF-alpha and IL-1beta production in LPS-stimulated macrophages. These results suggest that the beneficial effects of ribavirin are mediated by inhibition of induction of macrophage proinflammatory cytokines and Th2 cytokines while preserving Th1 cytokines.
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PMID:Ribavirin inhibits viral-induced macrophage production of TNF, IL-1, the procoagulant fgl2 prothrombinase and preserves Th1 cytokine production but inhibits Th2 cytokine response. 953 10

Infection with mouse hepatitis virus strain 3 (MHV-3) results in lethal fulminant hepatic necrosis in fully susceptible BALB/c mice compared to the minimal disease observed in resistant strain A/J mice. Macrophages play a central role in the pathogenesis of MHV-3-induced hepatitis. In the present study we have shown that MHV-3 infection of macrophages induces these cells to undergo apoptosis. Three methods to detect apoptosis were applied: flow cytometry analysis of nuclear DNA content, fluorescence microscopic visualization of apoptotic cells labeled by the TUNEL assay, and gel electrophoresis to detect DNA laddering. Apoptosis in A/J and BALB/c macrophages was first detected at 8 h postinfection (p.i.) and reached a maximum by 12 h p.i. The degree of MHV-3-induced apoptosis was much greater in A/J-derived macrophages than in BALB/c-derived cells. Apoptosis was inversely correlated with the development of typical MHV cytopathology, namely syncytia formation. Infected macrophages from A/J mice did not form synctia in contrast to the extensive synctia formation observed in BALB/c-derived macrophages. In MHV-3-infected BALB/c macrophage cultures, apoptotic cells were not incorporated into syncytia. Apoptosis was also inversely correlated with the expression of MHV-3-induced fgl2 prothrombinase in macrophages. These results add the murine coronavirus MHV-3 to the list of RNA-containing viruses capable of inducing apoptosis.
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PMID:Coronavirus MHV-3-induced apoptosis in macrophages. 977 Apr 18


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