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Biomedical subjects

I D Gust

Publications and source records attributed to I D Gust.

At least 91 records · Page 5Linked to original sources
PubMed1985

Restrictive events in the replication of hepatitis A virus in vitro.

Hepatitis A virus was purified from the feces of 2 patients with unrelated, naturally acquired infections and was inoculated into FRhK-4 cells. Analysis of protein synthesis by double-label coelectrophoresis and subtraction allowed the resolution of virus-specific proteins synthesized during infection. In FRhK-4 cells the two strains of virus studied produced markedly different profiles of virus-specified proteins, with an accumulation of high-molecular-weight proteins for strain HM790 relative to strain HM175, suggesting a level of restriction in the processing of the viral polyprotein.

Antigens, Surface↗
PubMed1984

Aetiology of fatal viral hepatitis in Melbourne. A retrospective study.

In the period from January 1971 to June 1983, 46 of 5477 patients (0.84%) admitted to Fairfield Hospital, Melbourne, with acute viral hepatitis died of fulminant hepatic failure. The case-fatality rate for patients with hepatitis A was 0.14%; for patients with hepatitis B, 0.84%; and for patients with non-A non-B (NANB) hepatitis, 2.29%. The highest case-fatality rates were observed in patients with post-transfusion hepatitis B (18.8%), and in patients with NANB hepatitis aged less than 5 years (50%) and 40 years and over (10%).

Adolescent↗
PubMed1984

Detection of delta infection using reagents obtained from the serum of patients infected with HBV.

A microtitre solid-phase radioimmunoassay (SPRIA) was developed for the detection of delta antigen (delta Ag) and antibody (anti-delta) using sera from subjects who had been infected with this agent as the source of antigen and antibody. The assay was compared with reference tests, which use delta antigen extracted from liver tissue obtained at autopsy, and found to be equally sensitive and specific.

Adult↗
PubMed1984

Viruses and virus-like particles in the faeces of dogs with and without diarrhoea.

Negative staining electron microscopy was used to identify viruses in 157 normal and 29 diarrhoeal faecal samples collected from 156 dogs admitted to an animal shelter during an 8 month period (March to October) in 1982. Seven distinct viral types were detected: 21-26 nm parvovirus-like particles, 28-31 nm astrovirus-like particles, a previously undescribed 34-35 nm "round" virus particle, coronavirus, coronavirus-like particles ( CVLP ), rotavirus and papova-like virus. Parvovirus-like particles alone were detected in 14 diarrhoeal and 50 normal faeces, astrovirus-like particles in 3 normal faeces, "round" viruses in 4 normal faeces, coronavirus in 2 diarrhoeal and 5 normal faeces, CVLP in one diarrhoeal and one normal faeces, rotavirus in 2 normal faeces, papova-like virus in one normal faeces, both parvovirus-like particles and coronavirus in 2 diarrhoeal and 2 normal faeces, parvovirus-like particles and rotavirus in one normal faeces and parvovirus-like and papova-like virus in one normal faeces. The significance of these findings in canine and human disease is discussed.

Animals↗
PubMed1984

Immunoglobulin M antibodies against hepatitis B core antigen in patients with chronic hepatitis B infection.

A batch of sera obtained from subjects with acute hepatitis B virus (HBV) infection, chronic carriers of hepatitis B surface antigen (HBsAg) who were either asymptomatic or who had chronic active hepatitis, and 32 sera from patients with HBsAg negative chronic active hepatitis were examined for the presence of antibodies against hepatitis B core antigen (anti-HBc) by radioimmunoassay (RIA). Sera containing anti-HBc were fractionated on sucrose density gradients to separate immunoglobulin M (IgM) and the titre of anti-HBc IgM was determined. In patients with acute HBV infection, anti-HBc IgM was detected during the acute phase of the illness with titres ranging from 1:128 to 1:4,096 (geometric mean titre 1:709). The titre of anti-HBc IgM fell rapidly over the following months and in most patients persisted at low levels for several years. Anti-HBc IgM was also detected in subjects with chronic HBV infection but with significantly lower titres. In asymptomatic carriers, anti-HBc IgM titres ranged from 1:4 to 1:32 (geometric mean titre 1:12), whilst carriers with chronic active hepatitis had titres ranging from 1:4 to 1:128 (geometric mean titre 1:35). By using a standardized assay procedure, the titre of anti-HBc IgM in a patient's serum may be of value in differentiating between acute and chronic HBV infection.

Carrier State↗
PubMed1983

A cross sectional study of markers of hepatitis B infection in Niue.

To determine whether the island of Niue would be a suitable location to evaluate the efficacy of hepatitis B vaccine, the prevalence of hepatitis B infection in the adult population was studied. Sera were collected from 1147 of 1244 residents above the age of 20 years, and tested for the presence of hepatitis B surface antigen (HBsAg) and specific antibody to the surface and core antigens (anti-HBs and anti-HBc) by solid-phase radioimmunoassay (SPRIA). Hepatitis B was found to be hyperendemic; 11.9% of those tested were found to be carriers of HBsAg and an additional 84% had detectable levels of anti-HBs or anti-HBc indicative of current or past infection. In this population HBV infection appears to occur early in life as the peak prevalence of serological markers was found in young adults. The almost universal infection of the population, their high rate of compliance with the study and the relatively high birth rate indicate that Niue would be a suitable location to evaluate methods of preventing hepatitis B infection.

Adult↗
PubMed1983

Replication of human rotavirus in cell culture.

Nine strains of human rotavirus were adapted to growth in CV-1 and/or MA-104 cells following pretreatment of virus with trypsin, incorporation of trypsin into culture medium, and use of roller cultures. Immunofluorescence was the most reliable method for the detection of virus replication, although characteristic cytopathic effects were produced sporadically by most isolates. Virus could be readily detected in supernatant fluids of cell cultures and in cell sections by electron microscopy.

Animals↗
PubMed1983

Characterization of a precipitating antigen detected in the serum of patients with viral hepatitis.

During a search for the aetiological agent of non-A non-B hepatitis, a precipitating antigen was detected in the sera of some patients during the acute phase of their illness. The antigen was detected by agar gel diffusion using antibody from convalescent sera obtained from patients with non-A non-B hepatitis, and from haemophiliac sera. The antigen was usually detected early in the patient's illness, disappearing as liver function tests returned to normal. In some patients specific antibody appeared during the convalescent phase of the disease. The antigen does not appear to be specific for non-A non-B hepatitis, as it could be detected with similar frequency in patients with hepatitis A or hepatitis B and some patients with other liver disorders. Biochemical and biophysical studies suggest that the antigen is probably an abnormal lipoprotein produced as a result of acute liver damage.

Antigens↗
PubMed1983

Monoclonal antibodies against hepatitis A virus.

Three monoclonal antibodies (K2-4F2, K3-2F2, and K3-4C8) of the immunoglobulin G2a class were raised against hepatitis A virus. The specificity of these antibodies was confirmed by immune electron microscopy, solid-phase radioimmunoassay, and in vitro neutralization in cell culture. Binding studies suggested that they all recognize closely related antigenic determinants. These monoclonal antibodies should prove to be of great value as diagnostic and research reagents.

Animals↗
PubMed1983

Taxonomic classification of hepatitis A virus.

Sufficient data have accumulated to permit the ICTV Ad Hoc Study Group on the Taxonomy of Hepatitis Viruses to recognize hepatitis A virus as a picornavirus. Within the family Picornaviridae, hepatitis A virus closely resembles members of the genus Enterovirus.

Enterovirus↗
PubMed1983

The effect of glucocorticoid hormones on release of HBsAg from PLC/PRF/5 (Alexander) hepatoma cells.

The glucocorticoid hormones dexamethasone, beta-methasone, and cortisone enhanced HBsAg release from PLC/PRF/5 cells by 40 per cent, 40 per cent and 10 per cent respectively, as compared to untreated controls. In the same experiments dexamethasone and betamethasone depressed the viable cell population by 20 per cent compared to the controls whereas cortisone had no significant effect. Immune electron microscope studies of the HBsAg material revealed no morphological differences compared to the control. Thus the glucocorticoid hormones dexamethasone, betamethasone and cortisone induce quantitative enhancement of HBsAg release without significant qualitative change. It is suggested that quantitative change in HBsAg release relates at least in part to the cell cycle of PLC/PRF/5 cells.

Betamethasone↗
PubMed1983

Live attenuated vaccine for hepatitis A.

The successful development of hepatitis B vaccines has stimulated interest in the active immunoprophylaxis of type A hepatitis. The development of hepatitis A vaccines has been simplified by the ability to propagate HAV in tissue culture systems and the availability of animal model systems, including the chimpanzee and certain species of marmosets in which to evaluate safety and efficacy of candidate vaccines. Both inactivated and live, attenuated hepatitis A vaccines are possible, but the limited replicative ability of HAV in tissue culture makes the former impractical at present. However, HAV appears to be rapidly attenuated by serial passage in tissue culture and such attenuated strains are candidates for a live, attenuated vaccine similar to the Sabin polio vaccine. The HM-175 strain of HAV, recovered from the stool of a patient with type A hepatitis in Melbourne, Australia, was isolated directly in primary African green monkey kidney (AGMK), a cell substrate suitable for vaccine development. This strain has been serially passaged over 20 times in AGMK. The parent strain (stool extract) and virus at tissue culture passages 10 and 20 were evaluated for infectivity and virulence in seronegative chimpanzees. The parent strain produced evidence of liver damage (elevated liver enzymes) at all dilutions of infectious virus tested. In contrast, tissue culture-passaged virus was fully infectious for chimpanzees, but did not produce biochemical evidence of hepatitis. Similarly, hepatitis A viral antigen could not be detected in liver biopsies and little or no viral antigen could be detected in acute phase stool samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

ELISA assay for IgG autoantibody to G-actin: comparison of chronic active hepatitis and acute viral hepatitis.

An ELISA was developed to test for IgG autoantibody to rabbit skeletal muscle G-actin in liver disease. To express results of the ELISA, we used a single reference serum with known high anti-actin activity, and assessed binding of test sera as a percentage of that displayed by the reference antiserum. Antibody to G-actin was measured in 40 sera from patients with chronic active hepatitis (CAH), 39 from acute viral hepatitis A (Hep A), 46 from acute viral hepatitis B (Hep B), 23 from non-A, non-B hepatitis (Hep non-A, non-B), 31 from systemic lupus erythematosus (SLE), 21 from scleroderma and 93 from normal persons. The results were compared with those obtained using indirect immunofluorescence tests with frozen sections of rodent stomach or fibroblast monolayers as substrates. Anti-G-actin activity of serum was significantly higher (P less than 0.001) in CAH (mean 63% +/- 23, range 18-110) than in controls (mean 15% +/- 12, range 0-51), systemic lupus erythematosus (mean 25% +/- 16, range 8-76), scleroderma (mean 23% +/- 13, range 3-59), Hep A (mean 24% +/- 11, range 6-25), Hep B (17% +/- 8, range 2-36), or Hep non-A, non-B (mean 23% +/- 11, range 7-53). There was no significant difference (P greater than 0.05) in the occurrence of anti-G-actin activity of serum in Hep A, Hep B or non-A, non-B compared with controls. At an ELISA reading of greater than or equal to 40% (mean + 2 s.d. of controls) the assay detected autoantibodies to G-actin in 85% of CAH, compared to 80% on fibroblast monolayers and 70% on rodent stomach. The ELISA described in the present study is a simple, sensitive and quantitative assay for autoantibody to G-actin. It should prove useful in assessing subspecificities of actin antibodies in liver diseases, and in differential diagnosis, particularly CAH from acute viral hepatitis.

Actins↗
PubMed1983

Immunisation against hepatitis B.

Over the past decade it has been recognised that viral hepatitis is due to at least three different agents. Two of these--the viruses responsible for hepatitis A and hepatitis B--have been identified and characterised. A safe, effective subunit vaccine against hepatitis B is now available in Australia and should assist greatly in the control of this important disease.

Adolescent↗