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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical syndrome of acute liver failure produced by fulminant viral hepatitis can be reproduced in mice by infection with murine hepatitis virus strain 3 (MHV-3). Although it is clear that MHV-3-induced hepatitis depends upon macrophage activation and the expression of a specific prothrombinase, fgl-2, the signaling pathways involved in virally stimulated cell activation are unclear. Since we had previously found that MHV-3 induces the tyrosine phosphorylation of cellular proteins, we investigated the roles of the mitogen-activated protein kinase (MAPK) proteins. In a series of Western blots, immunoprecipitation and in vitro kinase assay studies, we found that both the extracellular signal-related kinase (ERK) and p38 MAPK proteins are tyrosine-phosphorylated and activated following exposure of murine peritoneal exudative macrophages (PEM) to MHV-3. Although p38 phosphorylation and activity are induced soon after MHV-3 exposure, peaking by 1-5 min, ERK phosphorylation and activity increase more gradually, peaking at 20-30 min and gradually fading thereafter. Interestingly, whereas selective p38 inhibition with SB203580 (1-20 microM) abolished the virally stimulated induction of fgl-2 mRNA, protein, and functional activity, selective ERK inhibition with PD98059 (1-50 microM) limited fgl-2 functional activity but had little to no effect on fgl-2 mRNA or protein levels. Moreover, whereas inhibition of ERK had no effect on p38 activity, p38 inhibition consistently increased MHV-3-induced ERK activity. To ensure that these pathways were relevant in vivo, MHV-3 was injected intraperitoneally, and peritoneal exudative macrophages were collected. Again, MHV-3 exposure led to increased p38 and ERK tyrosine phosphorylation. These data argue that MHV-3 induces tightly interconnected ERK and p38 MAPK cascades in the macrophage both in vitro and in vivo. Although the ERK and p38 MAPK proteins have discordant effects at the level of fgl-2 expression, both converge at the level of its activity, suggesting that targeted MAPK inhibition may ultimately be useful in the modulation of viral hepatitis.
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PMID:Murine hepatitis virus strain 3 induces the macrophage prothrombinase fgl-2 through p38 mitogen-activated protein kinase activation. 982

Using a set of parental and recombinant murine hepatitis virus strains, we demonstrate that the nucleocapsid protein induces transcription of the novel fgl2 prothrombinase gene and elevated procoagulant activity in those strains that produce fulminant hepatitis. Chinese hamster ovary cells cotransfected with a construct expressing nucleocapsid protein from susceptible strains and with a luciferase reporter construct containing the fgl2 promoter showed a 6-fold increase in luciferase activity compared with nontransfected cells or cells cotransfected with a construct expressing nucleocapsid protein from resistant strains. Two deletions found at coding sites 111-123 and 1143-1145 of structural domains I and III, respectively, of the nucleocapsid gene may account for the differences between pathogenic and nonpathogenic strains. Preliminary mapping of the fgl2 promoter has defined a region from -372 to -306 upstream from the ATG translation initiation site to be responsive to nucleocapsid protein. Hence, mapping of genetic determinants in parental and recombinant strains demonstrates that the nucleocapsid protein of strains that induce fulminant hepatitis is responsible for transcription of the fgl2 prothrombinase gene. These studies provide new insights into the role of the nucleocapsid gene in the pathogenesis of viral hepatitis.
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PMID:The nucleocapsid protein of murine hepatitis virus type 3 induces transcription of the novel fgl2 prothrombinase gene. 1018 67

In the present studies, we report the cloning and structural characterization of the HFGL2 gene and its functional role in human fulminant hepatitis. The HFGL2 gene is approximately 7 kb in length with 2 exons. The putative promoter contains cis element consensus sequences that strongly suggest the inducibility of its expression. From the nucleotide sequence of the human gene, a 439-amino acid long protein is predicted. The overall identity between the murine fgl2 and hfgl2 coded proteins is over 70%. About 225 amino acids at the carboxyl end of these molecules are almost 90% identical, and correspond to a well-conserved fibrinogen-related domain. Both HFGL2 and FGL2 encode a type II transmembrane protein with a predicted catalytic domain toward the amino terminus of the protein. Transient transfection of Chinese hamster ovary (CHO) cells with a full-length cDNA of HFGL2 coding region resulted in high levels of prothrombinase activity. Livers from 8 patients transplanted for fulminant viral hepatitis were examined for extent of necrosis, inflammation, fibrin deposition, and HFGL2 induction. In situ hybridization showed positive staining of macrophages in areas of active hepatocellular necrosis. Fibrin stained positively in these areas and was confirmed by electron microscopy. These studies define a unique prothrombinase gene (HFGL2) and implicate its importance in the pathogenesis of fulminant viral hepatitis.
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PMID:Molecular and functional analysis of the human prothrombinase gene (HFGL2) and its role in viral hepatitis. 1075 47

For diseases in which thrombosis plays a pivotal role, such as virus-induced fulminant hepatitis, fetal loss syndrome, and xenograft rejection, the major procoagulant has remained elusive. Here we describe the isolation and functional expression of a distinct human prothrombinase, termed FGL2. The murine fgl2 gene product has been implicated in the pathophysiology of murine fulminant hepatitis. The predicted ORF corresponds to a 439-amino-acid type II integral membrane protein that contains a carboxy-terminal Fibrinogen-related domain. Functional analysis showed that FGL2-encoded protein is indeed a prothrombinase. This enzyme is a serine protease and directly cleaves prothrombin to thrombin. The FGL2 gene is a single-copy gene in the haploid human genome and has two exons separated by a 2195-bp intron expressing two mRNA transcripts of 1.5 and 5.0 kb. The 5'-flanking region contains putative cis-elements including a TATA box, an AP1 site, CEBP sites, Sp1 site, and Ets binding domains. By both radiation hybrid analyses and fluorescence in situ hybridization, human FGL2 was localized to 7q11.23.
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PMID:Genomic characterization, localization, and functional expression of FGL2, the human gene encoding fibroleukin: a novel human procoagulant. 1117 Jul 50

The antiphospholipid syndrome has rarely been described in patients with autoimmune hepatitis. Two cases with type I autoimmune hepatitis and antiphospholipid syndrome are presented. The first case is that of a 53-year-old Caucasian female with a history of arterial thrombosis and fetal loss who was submitted to clinical and laboratory testing due to persistent transaminasaemia and was found to have autoimmune hepatitis. Antiphospholipid antibodies (anticardiolipin antibodies and lupus anticoagulant) were positive. The second case is that of a 31-year-old Caucasian woman with a history of autoimmune hepatitis who was submitted to laboratory testing due to a second-trimester fetal death, revealing an increased activated partial thromboplastin time and positive antiphospholipid antibodies. In conclusion, secondary antiphospholipid syndrome may accompany autoimmune hepatitis.
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PMID:Autoimmune hepatitis associated with the antiphospholipid syndrome. 1139 42

fgl2 prothrombinase, by its ability to generate thrombin, has been shown to be pivotal to the pathogenesis of viral-induced hepatitis, cytokine-induced fetal loss syndrome, and xeno- and allograft rejection. In this study, the molecular basis of fgl2 prothrombinase activity was examined in detail. Purified fgl2 protein generated in a baculovirus expression system had no measurable prothrombinase activity, whereas the activity was restored when the purified protein was reconstituted into phosphatidyl-L-serine-containing vesicles. Reconstituted fgl2 catalyzed the cleavage of human prothrombin to thrombin with kinetics consistent with a first order reaction, with an apparent V(max) value of 6 mol/min/mol fgl2 and an apparent K(m) value for prothrombin of 8.3 microM. The catalytic activity was totally dependent on calcium, and factor Va (500 nM) enhanced the catalytic efficiency of fgl2 by increasing the apparent V(max) value to 3670 mol/min/mol fgl2 and decreasing the apparent K(m) value for prothrombin to 7.2 microM. By a combination of site-directed mutagenesis and production of truncated proteins, it was clearly shown that residue Ser(89) was critical for the prothrombinase activity of fgl2. Furthermore, fgl2 prothrombinase activity was not inhibited by antithrombin III, soybean trypsin inhibitor, 4-aminobenzamidine, aprotinin, or phenylmethylsulfonyl fluoride, whereas diisopropylfluorophosphate completely abrogated the activity. In this work we provide direct evidence that fgl2 cleaves prothrombin to thrombin consistent with serine protease activity and requires calcium, phospholipids, and factor Va for its full activity.
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PMID:Kinetic analysis of a unique direct prothrombinase, fgl2, and identification of a serine residue critical for the prothrombinase activity. 1199 72

Treatment of hemorrhagic diathesis after saline-solution-induced abortion is discussed. A 23-year-old woman who had a therapeutic abortion by intraamniotic instillation of 23% saline solution developed uterine bleeding 2 hours after the fetus had passed. Her fibrinogen level was 125 mg% (normal 250-450 mg%) and her partial thromboplastin time was 97 seconds (normal 45 seconds). 2 units of fibrinogen, followed by immune serum globulin, were administered to the patient. Approximately 2 1/2 months later the patient developed hepatitis. The question of whether or not this was proper treatment for her low fibrinogen state was asked. The consultant (author) stated that the fibrinogen could have been kept in reserve for the unlikely emergency of increasing fibrinogenopenia or hemorrhage. The addition of the fibrinogen substrate could (rarely) exacerbate disseminated intravascular coagulation as well as inoculate the patient with hepatitis virus. In a patient such as this, usually needs are met with transient obstetric and medical support since body processes restore the depleted hemostatic and fibrinolytic mechanisms.
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PMID:Treatment of hemorrhagic diathesis after saline-solution-induced abortion. 1230 85

Fibrinogen-like protein 2/fibroleukin (Fgl2) plays a pivotal role in the pathogenesis of both experimental and human fulminant hepatic failure. We have reported recently that the nucleocapsid (N) protein from strains of murine hepatitis virus (MHV-3, MHV-A59), which cause massive hepatocellular necrosis but not from strains (MHV-JHM, MHV-2) which do not produce serious liver disease, induces transcription of fgl2. The purpose of the present study was to characterize both viral and host factor(s) necessary for viral induced transcription of fgl2. Mutation of residues Gly-12, Pro-38, Asn-40, Gln-41, and Asn-42 within domain 1 of the N protein of MHV-A59 to their corresponding residues found in MHV-2 abrogated fgl2 transcription, whereas mutation of other N protein domains, including a protein expressed from an internal reading frame (I protein), did not affect fgl2 gene transcription. We then examined the -372 to -306 sequence within the 1.3-kb fgl2 promoter region upstream from the transcription start site that was previously identified as necessary for N protein-induced gene transcription. We demonstrated that the -331/-325 HNF4 cis-element and its cognate transcription factor, HNF4alpha, are necessary for virus-induced fgl2 gene transcription. In uninfected macrophages and macrophages infected with MHV-2, an unidentified protein occupies the HNF4 cis-element. Following stimulation with MHV-A59, it was shown by electrophoretic mobility shift assay that HNF4alpha binds the HNF4 cis-element in the fgl2 promoter. We further report the unprecedented presence of HNF4alpha in peritoneal macrophages. Collectively, the results of this study define both viral and host factors necessary for induction of fgl2 prothrombinase gene transcription in MHV infection and may provide an explanation for the hepatotrophic nature of MHV-induced fulminant hepatic failure.
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PMID:Induction of prothrombinase fgl2 by the nucleocapsid protein of virulent mouse hepatitis virus is dependent on host hepatic nuclear factor-4 alpha. 1259 8

Nodular regenerative hyperplasia (NRH) of the liver is a local hyperplastic response of hepatocytes, probably due to vascular abnormalities. Since it was shown in a few case reports that NRH may be associated with antiphospholipid antibodies (APA) we wanted to analyze the relevance of APA in patients with this disease. Sera from 13 patients with histologically defined NRH were tested for APA by an in-house ELISA using as antigens cardiolipin (CL), beta2-glycoprotein I (beta2-gp I), phosphatidylserine (PS), and thromboplastin (TP), a mixture of different phospholipids and phospholipid-binding proteins. As controls, sera from patients with serologically and histologically defined autoimmune liver diseases (primary biliary cirrhosis n = 14; autoimmune hepatitis n = 14) without histological evidence for NRH as well as from 14 healthy blood donors were analyzed. 77% of the NRH patients had APA. In 46% they were directed against CL. In contrast, only 14% of the patients with autoimmune liver diseases and 14% of the healthy controls had anti-CL antibodies (p < 0,05). Antibodies to beta2-gp I and TP did not discriminate between NRH and autoimmune liver diseases. Anti-PS antibodies were not observed. These data indicate that determination of anti-CL antibodies in NRH may help to identify a subgroup of patients in whom an 'organ-specific antiphosholipid syndrome' of the liver may be involved in the pathogenesis.
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PMID:Nodular regenerative hyperplasia (NRH) of the liver--a manifestation of 'organ-specific antiphospholipid syndrome'? 1263 4

During the period from July 1, 1999 to September 30, 2000, 9 children with severe adenovirus infection were treated at Chang Gung Children's Hospital. The mean age was 22 months (range, 5-50 months). All of them had lower respiratory tract infections, which manifested as lobar or segmental pneumonia and pleural effusion. Eight (88.9%) of the 9 patients required intensive care and 4 of them required mechanical ventilation. Abnormal laboratory findings included leukocytosis, elevated C-reactive protein, anemia, and prolonged prothrombin time and partial thromboplastin time. Extrapulmonary complications included hepatitis (6 cases), encephalitis (3), conjunctivitis (3), periorbital ecchymosis (1), and coagulopathy (2). One patient died, resulting in a mortality rate of 12.5%. Follow-up at 3 months postdischarge, 5 patients (62.5% of survivors) had bronchiolitis obliterans and/or organizing pneumonia. Seven patients were infected by serotype 3 adenovirus, 1 patient by serotype 2, and another by serotype 11. In conclusion, the clinical, laboratory, and radiographic features of severe adenovirus infection may mimic bacterial infection. Rapid progression of the clinical course despite antibiotic therapy and the presence of unusual extrapulmonary symptoms are important clinical clues in the diagnosis of severe adenoviral infection.
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PMID:Severe adenovirus infection in children. 1274 31


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