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G Kuo

Publications and source records attributed to G Kuo.

67 records · Page 4Linked to original sources
PubMed1990

The putative nucleocapsid and envelope protein genes of hepatitis C virus determined by comparison of the nucleotide sequences of two isolates derived from an experimentally infected chimpanzee and healthy human carriers.

cDNA fragments of a 5'-terminal region of the hepatitis C virus (HCV) genome were isolated by the reverse polymerase chain reaction from RNA extracted from plasma samples of healthy Japanese carriers. Their nucleotide sequence was compared with that of the original isolate which had been passaged twice in chimpanzees. No deletions or insertions were observed between the two sequences in the regions examined. Both the 5' untranslated and putative nucleocapsid (core) protein regions were highly conserved (99% and 91% nucleotide identities, respectively). In contrast, the region immediately downstream which encodes a putative envelope glycoprotein(s) showed only 74% nucleotide identity between the two isolates. At the polypeptide level, the core and envelope domains showed 97% and 75% amino acid identities, respectively. This envelope variation may reflect the adaptation of HCV to the different hosts and/or the result of immunological selection. The highly conserved nucleotide sequence of the 5' untranslated and core regions may play an important regulatory role in the life cycle of HCV.

Amino Acid Sequence↗
PubMed1989

A cDNA fragment of hepatitis C virus isolated from an implicated donor of post-transfusion non-A, non-B hepatitis in Japan.

Recently, a cDNA from the hepatitis C virus (HCV) RNA genome has been isolated in the USA from a chronically infected chimpanzee. In order to isolate HCV cDNA derived from human material, RNA was extracted from plasma of a Japanese blood donor implicated in post-transfusion non-A, non-B hepatitis and HCV cDNA was synthesized and amplified by the PCR method using HCV-specific oligonucleotide primers. The cDNA fragment, 583 nucleotides long, showed 79.8% homology at the nucleotide level and 92.2% homology at the amino acid level compared with the prototype HCV cDNA. These results provides further evidence to show that HCV is closely associated with the development of post transfusion non-A, non-B hepatitis.

Amino Acid Sequence↗
PubMed1989

Detection of antibody to hepatitis C virus in prospectively followed transfusion recipients with acute and chronic non-A, non-B hepatitis.

We measured antibody (anti-HCV) to hepatitis C virus, which causes non-A, non-B hepatitis, by radioimmunoassay in prospectively followed transfusion recipients and their donors. Of 15 patients with chronic non-A, non-B hepatitis documented by liver biopsy, all seroconverted for the antibody; of 5 with acute resolving non-A, non-B hepatitis, 3 (60 percent) seroconverted. The development of anti-HCV was delayed (mean delay, 21.9 weeks after transfusion, or 15 weeks after the onset of clinical hepatitis) and took approximately one year in one patient. Antibody has persisted in 14 of the 15 patients with chronic disease (mean follow-up, greater than or equal to 6.9 years; maximum, greater than or equal to 12), but has disappeared in the 3 with acute resolving disease after a mean of 4.1 years. Anti-HCV was detected in samples of donor serum given to 14 (88 percent) of the 16 anti-HCV-positive patients for whom all donor samples were available. Only 33 percent of the anti-HCV-positive donors tested had an elevated serum concentration of alanine aminotransferase; 54 percent were positive for antibody to the hepatitis B core antigen (anti-HBc). We conclude that hepatitis C virus is the predominant agent of transfusion-associated non-A, non-B hepatitis and that screening of donors for anti-HCV could prevent the majority of cases of the disease. "Surrogate" assays for anti-HBc and alanine aminotransferase would have detected approximately half the anti-HCV-positive donors involved in the transmission of hepatitis that we identified.

Acute Disease↗
PubMed1989

Prevalence of antibodies to hepatitis C virus in Italian patients with hepatocellular carcinoma.

A sensitive radioimmunoassay was used to detect antibodies to hepatitis C virus (HCV) in patients with hepatocellular carcinoma and chronic hepatitis. HCV antibodies (anti-HCV) were detected in 86 of 132 patients with hepatocellular carcinoma with no relation to the presence or absence of hepatitis B surface antigen (HBsAg). The prevalence of anti-HCV was also high in patients with diseases thought to predispose to hepatocellular carcinoma, such as non-A, non-B chronic hepatitis and cirrhosis (74%). In HBsAg-negative patients with hepatocellular carcinoma the prevalence of anti-HCV was lower than that in patients with non-A, non-B chronic hepatitis (16% vs 55%); the prevalence of serum antibodies to hepatitis B core antigen (anti-HBc), a marker of hepatitis B virus infection, was 70% and 28%, respectively. In HBsAg-negative patients with hepatocellular carcinoma, anti-HCV and anti-HBc occurred together nearly three times as often as in patients with chronic hepatitis (54% vs 19%). These data indicate that, in Italy, HCV is an important factor associated with hepatocellular carcinoma and non-A, non-B chronic hepatitis.

Adult↗
PubMed1989

Anti-hepatitis C antibodies and non-A, non-B post-transfusion hepatitis in The Netherlands.

In a prospective study carried out in the Netherlands (1984-86) to establish the incidence of post-transfusion hepatitis non-A, non-B (PTH-NANB) in patients undergoing open heart surgery, 393 patients received 5315 blood product transfusions. PTH-NANB developed in 9 patients (index cases); stored serum samples from these patients and from 9 control patients, matched for age, sex, and number of blood product transfusions, as well as serum samples of all implicated blood products, were selected retrospectively. Sera were tested under code with a radioimmunoassay for the detection of antibodies to hepatitis C virus (anti-HCV). PTH-NANB patients received 151 blood product transfusions and control patients 140. 4 of 9 PTH-NANB patients (3/5 chronic, 1/4 acute resolved hepatitis) and 0/9 controls seroconverted. 7 of the transfusions given to PTH-NANB patients but none of those given to control patients were anti-HCV positive. In 7 of 9 serum sets from PTH-NANB index cases plus implicated donors, either a donor or the recipient was anti-HCV positive. Among the donors implicated in transmission of PTH-NANB there was a strong correlation between raised alanine aminotransferase levels and the presence of anti-HCV antibodies.

Alanine Transaminase↗
PubMed1989

An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis.

A specific assay has been developed for a blood-borne non-A, non-B hepatitis (NANBH) virus in which a polypeptide synthesized in recombinant yeast clones of the hepatitis C virus (HCV) is used to capture circulating viral antibodies. HCV antibodies were detected in six of seven human sera that were shown previously to transmit NANBH to chimpanzees. Assays of ten blood transfusions in the United States that resulted in chronic NANBH revealed that there was at least one positive blood donor in nine of these cases and that all ten recipients seroconverted during their illnesses. About 80 percent of chronic, post-transfusion NANBH (PT-NANBH) patients from Italy and Japan had circulating HCV antibody; a much lower frequency (15 percent) was observed in acute, resolving infections. In addition, 58 percent of NANBH patients from the United States with no identifiable source of parenteral exposure to the virus were also positive for HCV antibody. These data indicate that HCV is a major cause of NANBH throughout the world.

Antibodies, Viral↗
PubMed1989

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.

Animals↗
PubMed1989

Cachectin/tumor necrosis factor-alpha alters red blood cell kinetics and induces anemia in vivo.

Chronic inflammatory diseases are often associated with decreased red blood cell (RBC) mass. The cytokines cachectin/tumor necrosis factor-alpha (TNF) and interleukin 1 (IL 1) are produced by monocytes/macrophages in response to many inflammatory stimuli and have been implicated in the anemia of chronic disease. This study was undertaken to evaluate the mechanisms by which cachectin/TNF, IL 1, or endotoxin induce anemia. Hematologic parameters and RBC kinetics were quantitated in rats given chronic sublethal quantities of either recombinant human cachectin/TNF, recombinant human IL 1 alpha, or Salmonella endotoxin for 7 days. Cachectin/TNF or endotoxin treatment resulted in a 25 or 31% decrease, respectively, in total RBC mass, whereas RBC mass was unchanged by IL 1 administration. Anemia associated with either chronic cachectin or endotoxin administration was characterized by normal mean corpuscular volume, mean corpuscular hemoglobin content, and reticulocyte numbers. [59Fe]RBC survival was significantly shortened in animals given cachectin, IL 1 or endotoxin, but the magnitude of the response was greatest in cachectin/TNF-or endotoxin-treated rats. Although cachectin/TNF-IL 1-, or endotoxin treatment resulted in similar hypoferremia and shortened plasma iron half-life, endotoxin or cachectin/TNF treatment (but not IL 1) significantly reduced the incorporation of plasma 59Fe into newly synthesized RBCs. We conclude that chronic cachectin/TNF administration produces anemia by decreasing RBC synthesis and reducing the life span of circulating RBCs. An endogenous cachectin/TNF response during inflammatory disease may contribute to an associated anemic state, whereas the modestly reduced red cell life span induced by IL 1 does not lead to a net reduction in RBC mass, presumably owing to a preserved RBC synthetic rate.

Anemia↗
PubMed1989

Tumor necrosis factor-induced lung injury is not mediated by platelet-activating factor.

Both tumor necrosis factor (TNF) and platelet-activating factor (PAF) have been incriminated as mediators of endotoxic shock. Since TNF stimulates PAF synthesis in vitro, we tested the hypothesis that PAF mediates TNF-induced lung injury in vivo using specific PAF receptor antagonists. Intravenous infusion of purified human recombinant TNF resulted in peripheral neutrophilia, lymphocytopenia, and hemoconcentration, caused hemorrhagic injury to the cecum, and increased lung tissue levels of thromboxane B2 and 6-ketoprostaglandin F1 alpha. In addition, plasma glutathione disulfide (GSSG), an in vivo index of oxidative stress, was significantly increased. TNF (0.01-1 mg/kg) caused a dose-dependent increase in lung permeability-surface area product (PS) measured in isolated perfused lungs removed from rats 90 min after injection of TNF. [Lung PS in controls and after 0.01, 0.1, and 1.0 mg/kg of TNF were 0.022 +/- 0.001, 0.027 +/- 0.002, 0.033 +/- 0.001, and 0.036 +/- 0.005, respectively (P less than 0.05 from control for TNF 0.1 and 1 mg/kg).] Pretreatment of the rats with the PAF receptor antagonists WEB 2086 (10 mg/kg) and SRI 63-441 (10 mg/kg), at doses that previously protected against endotoxin-induced lung injury, did not significantly affect TNF-induced (0.1 mg/kg) changes in hematocrit, plasma GSSG, or lung PS. Moreover, WEB 2086 (10 mg/kg) did not inhibit TNF-induced (1 mg/kg) lymphocytopenia or the increases in lung tissue eicosanoid products. We conclude that TNF causes oxidative stress, eicosanoid activation, and acute lung injury in rats by a mechanism largely independent of PAF receptor activation.

Animals↗
PubMed1989

Cachectin/TNF or IL-1 alpha induces cachexia with redistribution of body proteins.

Macrophage secretory products are suspected to participate in the severe lean tissue wasting related to chronic illness. The protein metabolic effects of chronic, 7-day cachectin/tumor necrosis factor (cachectin) or interleukin 1 alpha (IL-1 alpha) administration in vivo were studied in male Wistar rats that were 1) freely fed, 2) pair fed, 3) total protein and calorie starved, 4) twice daily lipopolysaccharide (LPS) administered, 5) twice daily cachectin administered, and 6) twice daily IL-1 alpha administered. LPS, cachectin, or IL-1 alpha administration produced anorexia; weight loss in these groups was comparable to respective pair-fed animals. However, LPS, cachectin, or IL-1 alpha accelerated peripheral protein wasting while preserving liver protein content, unlike the pattern in the pair-fed or starved animals in which loss of liver proteins and relative preservation of skeletal muscle protein were observed. The decrease in skeletal muscle protein content in LPS- or cytokine-treated animals was associated with coordinate decreases in muscle mRNA levels for the myofibrillar proteins myosin heavy chain, myosin light chain, actin, and in the 18S and 28S subunits of ribosomal RNA. We conclude that chronic exposure to the cytokines, IL-1 alpha or cachectin, can simulate those body and muscle protein changes seen in experimental LPS administration or chronic disease and markedly differ from the pattern of protein redistribution due to caloric restriction.

Animals↗
PubMed1988

Crystallization of trimeric recombinant human tumor necrosis factor (cachectin).

Crystals of tumor necrosis factor (TNF) have been obtained in two forms. Rhombohedral crystals grow in 1.8 to 2.0 M ammonium sulfite, pH 7.8 at 21 degrees C, and tetragonal crystals grow in 2.6 M magnesium sulfate, pH 5.5 at 25 degrees C. Analysis of TNF by isoelectric focusing under native and denaturing conditions indicates that TNF molecules exist as trimers in solution. The rhombohedral cachectin crystals belong to space group R3 and have unit cell constants a = b = c = 47.65 A and alpha = beta = gamma = 88.1 degrees. Density determinations and the space group indicate that the unit cell contains one 51,000-dalton trimer. These crystals are stable in the x-ray beam and diffract to at least 1.85 A but are apparently twinned by merohedry. The tetragonal crystals are space group P4(3)2(1)2 or its enantiomorph P4(1)2(1)2 and have unit cell constants a = b = 95.08, c = 117.49. The asymmetric unit contains one trimer; the crystals are stable in the x-ray beam and diffract to beyond 3 A.

Crystallization↗