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Biomedical subjects

I D Gust

Publications and source records attributed to I D Gust.

At least 37 records · Page 2Linked to original sources
PubMed1992

Epidemiological patterns of hepatitis A in different parts of the world.

Serological surveys in many communities show a high prevalence of antibodies to hepatitis A virus (HAV) in people over the age of 50 years. However, few of that age can recall a previous episode of hepatitis, indicating that subclinical infections are common. The outcome of infection with HAV depends on the age at which infection occurs and, perhaps, the infectious dose. Fulminant disease is well recorded, with the frequency varying from one to eight per 1000 cases. Information on the frequency of hepatitis A can be obtained by analysing hospital records and notifications to health authorities or by serological surveys. In many countries, these data are limited and seriously underestimate the true frequency of the disease. At a conservative estimate, the incidence of disease in most developed countries is probably four to five times higher than the number of notifications. HAV appears to circulate in most parts of the world and to be responsible for both epidemic and sporadic disease. Three major patterns of infection are known which reflect different epidemiological situations. These are demonstrated by different patterns of the age-specific prevalence of antibodies to HAV which reflect standards of hygiene and sanitation, the degree of crowding of the population and opportunities for the virus to survive and spread.

Age Factors↗
PubMed1991

AIDS vaccines.

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AIDS Vaccines↗
PubMed1991

Hepatitis C antibody testing: problems associated with non-specific binding.

The prevalence of antibodies to hepatitis C virus (anti-HCV) was measured in a number of groups known to be at increased risk of blood-borne viral infections, using an enzyme-linked immunosorbent assay (EIA) based on a nonstructural peptide generated by recombinant DNA technology. The assay was repeatably reactive in 75.6% of men with haemophilia, 61.9% of intravenous drug users, 34.1% of homosexual men who were regular attenders at a gay sauna and 30.8% of prisoners. A lower reactivity was detected in sera collected from female prostitutes (10.4%), patients undergoing maintenance haemodialysis (5.9%), or renal transplantation (6.9%) and patients attending a sexually transmitted diseases clinic (6.2%). We also measured reactivity among inmates of a large institution for the mentally handicapped in which hepatitis B is known to be endemic, and in panels of sera which had been stored for 25-35 years. The test was positive in 41.1% of mentally handicapped patients with Down's syndrome and 7% of subjects with other forms of mental retardation. Similarly some 23% and 20% of sera collected in 1954 and 1964 from patients with a variety of illnesses were found to be reactive. As most diagnostic assays suffer from some degree of non-specificity and confirmatory tests for the anti-HCV assay were not initially available in Australia, we analysed the distribution of optical density (OD) values in the different groups, in an attempt to obtain an insight into the specificity of the results being obtained. Whereas the ODs of sera collected from patients with haemophilia and IVDU had a bimodal pattern, with two well separated sets of results on either side of the cut-off.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Viral↗
PubMed1991

The increased risk of fatal liver disease in renal transplant patients who are hepatitis Be antigen and/or HBV DNA positive.

To determine whether active viral replication is associated with increased morbidity and mortality in chronic carriers of hepatitis B virus (HBV) undergoing renal transplantation, we reviewed 23 years of experience at our hospital. Over the period 1966-1989, 42 chronic carriers of hepatitis B surface antigen (HBsAg) received renal transplants, 32 of whom had functioning grafts for 12 months or longer. Stored sera were tested for markers of hepatitis B virus, hepatitis C virus (HCV), and hepatitis delta virus (HDV) infection, and the serologic findings were correlated with clinical and biochemical data. The presence of HBV DNA and/or hepatitis Be antigen (HBeAg) in serum samples collected prior to transplantation was associated with an increased probability of death from liver disease. Whereas 5 of 10 patients in this group died of chronic liver disease, only 1 of 15 patients who were HBV DNA and/or HBeAg negative prior to transplantation died of liver disease. This difference is highly significant (P less than 0.02). No difference in outcome was attributable to age at transplantation, gender, country of birth, or the presence of abnormal hepatic transaminase levels prior to transplantation.

Adolescent↗
PubMed1991

Testing of saliva for antibodies to HIV-1.

To determine whether saliva is a potentially useful sample for screening for HIV infection when serum is not obtainable, saliva and serum samples from 50 HIV-infected and 50 uninfected subjects were tested for antibody to HIV-1 (anti-HIV-1) using a second-generation enzyme-linked immunosorbent assay (ELISA; Abbott) and prototype antibody-capture ELISA (Wellcome). Of saliva specimens from HIV-infected people, six gave negative results on the Abbott and one on the Wellcome assays; all specimens from uninfected people were negative by both assays. Sensitivity for the Abbott assay was therefore 88.0% [95% confidence interval (Cl) 76.2-94.4%], an unacceptable level for screening purposes. Sensitivity for the Wellcome assay was 98% (95% Cl 89.5-99.6%), a more satisfactory level for population screening. Further validation of this technique is necessary, and of methods for collection of saliva specimens in particular.

AIDS Serodiagnosis↗
PubMed1990

Epidemiology and hepatitis C virus in Victoria.

Parenterally transmitted non-A, non-B (NANB) hepatitis virus or hepatitis C virus is a common cause of both acute and chronic hepatitis. Using a recently developed enzyme-linked immunosorbent assay we looked at the prevalence of antibodies to hepatis C virus (anti-HCV) in a number of groups. People with haemophilia (75.6%) and intravenous drug users (61.9%) had the highest prevalence, while homosexual men attending a sauna (34.1%) and prisoners (30.8%) had a moderately high prevalence of anti-HCV. A lower prevalence of antibody was detected in female prostitutes (10.4%), institutionalised mentally retarded subjects (9.5%), homosexual men requesting human immunodeficiency virus (HIV) testing through their local doctor (8.8%), dialysis patients (5.9%), renal transplant patients (6.9%), and patients referred from a sexually transmitted diseases clinic (6.2%). The lowest prevalence of anti-HCV was recorded in women attending a provincial hospital for antenatal care (0.4%). The predominance of anti-HCV in groups of people exposed to blood-borne and sexually transmitted infections suggests that these routes may be primarily involved in the spread of hepatitis C virus infection.

Adult↗
PubMed1990

Humoral immune responses in mice using gamma inulin preparations as adjuvants for hepatitis B vaccines.

There is an urgent need for new, powerful adjuvants suitable for use with sub-unit and peptide vaccines in humans. We have measured the humoral immune response in BALB/c mice to vaccine formulations using recombinant HBsAg antigens, and gamma inulin and alum adjuvants. Using Merck, Sharpe & Dohme (MSD) HBsAg at 10 micrograms/mL, high levels of anti-HBs were generated and geometric mean S/N ratios of 88, 133 and 107 were obtained for alum absorbed vaccine, gamma inulin, and a mixture of the two adjuvants, respectively. A dilution series produced ED50 values of 0.08, 0.15 and 0.22 micrograms/mL respectively. In a second series of experiments comparing alum and algamulin (a complex of gamma inulin and alum), MSD HBsAg induced anti-HBs levels of 81 and 52, and ED50 values of 0.3 and 0.4 when used in conjunction with alum and algamulin, respectively. SKF HBsAg induced anti-HBs levels of 126 and 111 with alum and algamulin, and ED50 values of 0.11 and 0.075. The class, subclass and level of antibody produced in mice boosted with a second dose of vaccine at 21 days was also examined. Both alum and gamma inulin induced higher levels of total antibody, IgG1 and minor IgG subclasses than algamulin, or HBsAg alone. Overall, gamma inulin appears to be an equivalent adjuvant to alum, although their mechanisms of action are different. Mixtures or complexes of the two adjuvants appear to be less effective in inducing humoral immune responses in mice than either alone.

Adjuvants, Immunologic↗
PubMed1990

Altered sensitivity to antiviral drugs of herpes simplex virus isolates from a patient with the acquired immunodeficiency syndrome.

Acyclovir (ACV)-resistant herpes simplex virus type 2 (HSV-2) was isolated from a patient with acquired immunodeficiency syndrome after long-term but intermittent ACV therapy. These thymidine kinase-defective isolates were sensitive in vitro to foscarnet. While combined therapy with ACV and interferon produced only partial clinical improvement, the in vitro effect of this combination against an ACV-resistant isolate from the patient was strongly synergistic. A short course (10-12 days) of intravenous foscarnet controlled severe ulceration, and clinical improvement lasted 6 months. After recurrence and further courses of foscarnet, however, the patient responded poorly, and subsequent HSV isolates were resistant to both ACV and foscarnet and hypersensitive to aphidicolin.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Design of hepatitis A vaccines.

Hepatitis A is a major public health problem in many rapidly developing countries and it is still an important disease in many developed countries. Isolation of the virus in cell culture and access to reliable animal models has led to the development of several candidate vaccines. Both inactivated and attenuated vaccines have been developed which appear to be safe, antigenic and protective in laboratory animals. If studies in man support the data which have been obtained in other primates, the first commercially available vaccines are likely to be licensed within the next two years.

Animals↗
PubMed1990

Use of a conserved immunodominant epitope of HIV surface glycoprotein gp41 in the detection of early antibodies.

An enzyme immunoassay (EIA) utilizing a synthetic peptide analogue of HIV gp41 (amino acids 579-599, RILAVERYLKDQQLLGIWGCS) as antigen was compared with two commercial assays (Genetic Systems, Abbott ENVACORE) for the ability to detect antibodies in the early stages of infection. Two panels, consisting of 96 sera from 15 people and 140 sera from 44 people seroconverting to HIV, were examined. In the first group the synthetic peptide assay (gp41 EIA) detected antibodies before the Genetic Systems EIA in seven out of 15 people and concurrently in the remaining eight. With the second panel the Abbott ENVACORE assay detected antibodies before the gp41 EIA in two out of 44 people while the gp41 EIA detected antibodies first in six out of 44. In the remaining 36 people antibodies were detected simultaneously by the two tests. The gp41 EIA usually detected anti-HIV antibodies before or concurrently with the two commercial assays examined suggesting that the epitope cluster represented by this peptide is recognized early in infection.

AIDS Serodiagnosis↗
PubMed1990

Hepatitis A.

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Epidemiologic Factors↗
PubMed1989

Patterns of migration indicate sexual transmission of HTLV-I infection in non-pregnant women in Papua New Guinea.

The prevalence of infection with human T-cell leukaemia virus (HTLV-I) was studied in Madang Province on the north coast of Papua New Guinea. Serum specimens collected from non-pregnant women in 17 villages were tested for anti-HTLV-I by gelatin particle agglutination screening and confirmed by immunofluorescence and Western blotting. Overall, 13.9% of subjects were antibody-positive, with the prevalence of antibodies varying from less than 10% to 30% in villages situated less than 10 km apart. Two groups of migrant women were identified, and in both a parity-related increase in antibody prevalence which occurred only after marriage suggested that the predominant mode of transmission in migrant women was sexual. There was no parity-associated increase in anti-HTLV-I in indigenous women, and in contrast to migrant women, nulliparous indigenous women had a high prevalence of antibody (16.8% vs. 0%; p = 0.005). Vertical transmission cannot be excluded in indigenous women. No correlation was detected between the prevalence of anti-HTLV-I and a variety of indices of malarial infection.

Emigration and Immigration↗
PubMed1989

Control of HBV and HDV infection in an isolated Pacific Island: 1. Pattern of infection.

Hepatitis B virus (HBV) and hepatitis delta virus (HDV) infections are known to be hyperendemic in Nauru. Because of the consequences of chronic HBV infection, the Nauruan Government has commenced a program that aims to reduce and eventually eliminate hepatitis B infection by immunizing susceptible adults and children on the island and every newborn baby. At the outset of this program, a national seroepidemiological survey was undertaken. Eighty-eight percent of the population were tested, of whom 69.1% had markers of HBV infection. Evidence of superinfection with HDV was found in 22.7% of HBV carriers, with the highest prevalence in adolescents and young adults. All seronegative individuals were offered three doses of plasma derived hepatitis B vaccine. A post-vaccination survey of 64% of those vaccinated showed that 98% had developed circulating antibodies.

Adolescent↗
PubMed1989

Coronavirus-like particles in adults in Melbourne, Australia.

Coronavirus-like particle(s) (CVLP) are faecal-derived pleomorphic membrane bound virus-like particles characterised by a fringe of club-shaped spikes that measure about 27 nm in length. The association of CVLP with a variety of social, clinical, and epidemiological factors was examined after a 69 month survey of faeces received for routine testing at an infectious diseases hospital. CVLP was found most commonly in three groups: first, intellectually retarded individuals who were usually inmates of institutions; second, recent overseas travellers who were either Indochinese refugees/immigrants or were overseas travellers who had usually visited developing communities for lengthy periods; and, third, male homosexuals who had a history of multiple sexual contacts and/or venereal disease. It was concluded that the excretion of CVLP had a strong association with unhygienic living or working conditions irrespective of any clinical symptoms the individual might show.

Adolescent↗
PubMed1989

Detection of anti-HIV immunoglobulin M by particle agglutination following acute HIV infection.

In a study of 23 subjects infected with HIV, a modified particle agglutination assay was used to detect anti-HIV-specific immunoglobulin M (IgM). The presence of anti-HIV IgM was demonstrated in every subject, becoming detectable 1-2 weeks after the onset of acute symptoms, and showing a variable duration of 1-5 weeks. Anti-HIV immunoglobulin G (IgG) developed 1-2 weeks after anti-HIV IgM. Particle agglutination detected the presence of specific antibody up to 7-10 days earlier than the Abbott recombinant or Genetic Systems enzyme immunoassays. In this study, all subjects with acute infection became clearly positive by Western blot within 3 months of the onset of acute symptoms.

Acquired Immunodeficiency Syndrome↗