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Biomedical subjects

G G Frösner

Publications and source records attributed to G G Frösner.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Epidemiology of hepatitis A and B and yellow fever in Zaire].

In a sero-epidemiological study, clinically healthy persons from a rural area of Zaire were tested for antibodies against hepatitis A, B and yellow fever. There was a high prevalence of antibodies to hepatitis A-virus in early life: 90% of all children at the age of ten had antibodies in their sera. Similarly up to the age of 19 years almost 90% of all persons investigated were positive for hepatitis B (anti-HBc). The incidence of the hepatitis B-surface antigen in all ages was high. According to the method used, it totalled to 21% (capillary blood) or 32% (serum specimens). All these persons were asymptomatic HBsAg carriers. A carrier-rate of 20-30% is extremely high; it has been reported only in a few studies in tropical countries. 138 serum specimens from all age groups were tested for antibodies to yellow fever virus; 59 of them (43,4%) were positive. None of these persons reported a history of yellow fever; evidently they had undergone subclinical infections. Our findings show that yellow fever still is endemic in Central Africa. It may be concluded that all persons visiting Central Africa should be vaccinated against hepatitis A (passive prophylaxis), yellow fever and, if possible, against hepatitis B.

Adolescent↗
PubMed1984

Expression of hepatitis B virus core antigen gene is induced in human hepatoma cells by their growth in nude mice.

The human hepatoma cell line PLC/PRF/5 is persistently infected with hepatitis B virus. Cells cultured in vitro are known to produce the virus surface antigen but not be other structural virus proteins, the core and the e antigen. It is shown here that expression of the core antigen gene was inducible by growing the cells as a nude mouse tumour. The buoyant density in CsCl (1.31 to 1.32 g/ml) of core or e antigen produced in the tumours was very similar to that of virus core particles. Expression of the core antigen gene was shunt off by culture in vitro of core or e antigen-producing nude mouse tumour cells and induced again by subsequent passage of cells in the nude mouse. The experimental system thus allows studies on the regulation of expression of the core antigen gene.

Animals↗
PubMed1983

Post-transfusion hepatitis and its association with pooled clotting factors.

A prospective study of post-transfusion hepatitis was conducted in 97 adult patients undergoing open heart surgery. Twelve patients developed presumed non-A, non-B hepatitis (five of these were hospitalized and three were jaundiced), and all 12 had received clotting factors from pooled plasma (fibrinogen, factor VIII, factor IX complex) from different manufacturers. Of the remaining 85 patients none received these high risk plasma derivatives and none developed hepatitis. Multiple peak ALT elevation seems to be an indication of development of chronic non-A, non-B hepatitis. In addition to the 12 cases of presumed non-A, non-B hepatitis, nine cases of serological changes related to hepatitis B virus were observed as follows: six early booster reactions of anti-HBs, but not anti-HBc, in anti-HBs and anti-HBc positive persons; one late immunization-like response for anti-HBs and two serological hepatitis B infections without transaminase elevation. Five of the nine cases were also associated with the administration of pooled clotting factors.

Adult↗
PubMed1983

Topology and immunoreactivity of capsid proteins in hepatitis A virus.

Hepatitis A virus (HAV) was propagated in a hepatoma cell line and complete viral particles with a density of 1.34 g/ml were purified from cell extracts. The topography of the viral proteins (VPs) was studied by surface labelling with 125I and a solid-phase oxidant. The order of labelling intensity in complete particles was VP1 much greater than VP3 greater than VP2; labelling of VP4 was undetectable. When the particles were denatured with sodium dodecyl sulfate at 100 degrees C before iodination, the labelling efficiency was 6 times higher and the order of labelling intensity was VP3 greater than VP2 greater than VP1. After denaturation, the viral proteins no longer reacted with human anti-HAV antibody. The results suggest that (i) as with other picornaviruses, HAV exposes an essential part of VP1 at its surface whereas VP3 and especially VP2 are more hidden; (ii) naturally immunized individuals do not form detectable amounts of antibodies against the denatured capsid proteins. The apparent molecular weights of the VPs were 33000, 29000 and 28000 daltons.

Capsid↗
PubMed1982

Diagnostic significance of quantitative determination of hepatitis B surface antigen in acute and chronic hepatitis B infection.

HBsAg was determined quantitatively by radioimmunoassay and by Laurell electrophoresis in sera of 90 patients with acute hepatitis B, 57 patients with chronic hepatitis B, and 154 HBsAg positive blood donors. Of 55 patients with clearance of HBsAg from the circulation within six months, 54 (98%) showed an at least 50% reduction in concentration within 16 days. All 55 patients had such a decrease within 20 days. No such decrease was found in seven patients with acute hepatitis B who became HBsAg carriers. Therefore, quantitative HBsAg concentration in paired sera seems to be a reliable and early prognostic marker in acute hepatitis B. In patients with clearance of HBsAg most of the antigen is already present in the circulation at hospitalization and is eliminated with a mean half-life of 8.8 days. Patients with chronic hepatitis exhibit on average nearly the same HBsAg concentration (about 40,000 ng/ml) as patients with acute hepatitis B at hospitalization (about 39,000 ng/ml) and HBsAg positive blood donors on average a lower HBsAg concentration (about 8,000 ng/ml).

Blood Donors↗
PubMed1982

Enzyme-linked immunosorbent assay for acute adenovirus infection.

An enzyme-linked immunosorbent assay (ELISA) is described for demonstrating antibodies to the hexone antigen of adenoviruses. The antigen-coated, flat-bottomed microtiter plates are incubated sequentially with dilutions of patients' sera (2 h at 37 degrees C) and peroxidase-coupled anti-human IgG (2 h at 37 degrees C). After a final washing, orthophenylenediamine is added to the plates, and the absorbance (A) measured 30 min later. The ELISA was found to be a hundred-fold more sensitive than complement fixation. An evaluation methods for determining antibody concentration is described which correlates the absorbance of sera diluted 10(-3) to the absorbance of a reference serum containing an arbitrary value (100) of antibody. This methods avoids titration of sera and day-to-day assay variations by different background reactions. A significant increase in antibody concentration of acute-phase serum over that of convalescent phase serum is observed. The ability to test sera in a single dilution and the automatic reading of results and their evaluation by computer make this assay suitable for diagnostic laboratories.

Adenoviridae Infections↗
PubMed1981

Propagation of hepatitis A virus in human embryo fibroblasts.

human diploid fibroblasts and human primary liver cell carcinoma cells (PLC/PRF/5) were infected with hepatitis A virus (HAV) adapted to growth in cell culture or derived directly from human stool. Viral antigen was expressed in PLC/PRF/5 cells 28 days after infection with cell culture-adapted HAV, and 50 days after infection with virus from human stool. In human fibroblasts the periods until first expression of viral antigen were 90 and 210 days, respectively. During further passages of HAV in fibroblasts the time of first appearance of antigen decreased to about 28 days. Biophysical properties of HAV extracted from infected fibroblasts were comparable to those of HAV derived directly from human stool. Immunofluorescence studies showed that the antigen was located exclusively within the cytoplasm of the infected fibroblasts. Kinetics of antigen production indicated that an equilibrium between virus multiplication and cell metabolism was reached in persistently infected fibroblasts.

Antigens, Viral↗
PubMed1981

The physicochemical properties of infectious hepatitis A virions.

The propagation of hepatitis A virus (HAV) in the cell line PLC/PRF/5 made possible the radiolabelling in vivo of mature, infectious hepatitis A virions and the determination of their physicochemical properties. In contrast to poliovirus type 2 (160S, 1.340 g/ml), HAV had a sedimentation coefficient of 156 +/- 2S and a buoyant density of 1.332 g/ml in CsCl. The genome of HAV consisted of linear single-stranded RNA which sedimented at 32.5S under non-denaturing conditions. Compared to the size and sedimentation behaviour of poliovirus RNA (2.6 X 10(6) mol. wt., 35S) this corresponds to a mol. wt. of 2.3 X 10(6). Electrophoresis under fully denaturing conditions, however, revealed a mol. wt. of 2.8 X 10(6) and indicates the existence of relatively extended regions with secondary structure. The purified virus genome, containing a poly(A) sequence, served as a messenger for the synthesis of virus antigen in PLC/PRF/5 cells. Finally, in accordance with previous observations, the capsid of the virion was found to be constructed of three major polypeptides (VP1, 31 X 10(3); VP2, 26 X 10(3); VP3, 21 X 10(3) mol. wt.) and of two less readily demonstrable components probably corresponding to VP4 (8 X 10(3) to 10 X 10(3) mol. wt.) and the precursor polypeptide VP0 (40 X 10(3) mol. wt.).

Antigens, Viral↗
PubMed1981

Anti-HBc of IgM-class, HBeAg and anti-HBe in acute and chronic hepatitis B.

The presence and persistence of IgM antibody against hepatitis B core antigen (anti-HBc IgM) and the correlation with other HBV markers were studied in 42 patients, all of whom had acute HBsAg-positive hepatitis but whose subsequent diseases differed. All patients initially had anti-HBc IgM. In 13 out of 15 patients with uncomplicated acute hepatitis, anti-HBc IgM disappeared within 6 months after onset of the disease. In five out of 12 patients, who in spite of transient HBsAg developed chronic liver disease, the anti-HBc IgM persisted for more than 2 years. Among 15 patients with persistent HBsAg, anti-HBc IgM was present from 7 months to more than 8 years. Seroconversion from HBeAg to anti-HBe was observed in seven patients and in five of these anti-HBc IgM disappeared during the follow-up period. These results indicate that anti-HBc IgM can be used as a serological marker of recent or ongoing HBV infection.

Adolescent↗