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Biomedical subjects

G Wolters

Publications and source records attributed to G Wolters.

35 records · Page 2Linked to original sources
PubMed1984

Cellular and humoral immune reactions in chronic active liver disease. II. Lymphocyte subsets and viral antigens in liver biopsies of patients with acute and chronic hepatitis B.

The characteristics and distribution of the inflammatory infiltrate in liver biopsies of 25 patients with hepatitis B viral (HBV) infection were studied in relation to the distribution and expression of HBV antigens. Mononuclear subsets were characterized with monoclonal (OKT, OKM, Leu) antibodies to surface antigens. For the demonstration of viral antigens directly conjugated antibodies to surface (HBsAg), core (HBcAg) and 'e' (HBeAg) antigen were used. For the study of mutual relations all methods were performed on serial cut tissue sections. In chronic active hepatitis B (CAH-B, n = 12) OKT8+ lymphocytes of T cell origin were the only cell type present in areas with liver cell degeneration and T cell cytotoxicity appears to be the only immune mechanism. In chronic persistent hepatitis B (CPH-B, n = 7) the only conspicuous feature was the presence of many Leu 3+ lymphocytes of the helper/inducer population in the portal tracts. In acute hepatitis B (AHB, n = 6) OKT8+ cells of non-T origin (OKT1-,3-) and Leu 7+ cells of presumed natural killer (NK) potential predominated in the areas with liver cell necrosis, and non-T cell cytotoxicity appears to be the predominant immune mechanism. In none of these disease entities a positive spatial relation could be established between the cytotoxic cells and the demonstrable expression of HBV antigens in hepatocytes. It is concluded that differences in immunological reaction pattern may explain the different course in the three forms of HBV infection studied.

Acute Disease↗
PubMed1980

Improved Hepanostika, an enzyme-immunoassay for hepatitis B surface antigen.

Two modifications of Hepanostika were studied in order to improve this enzyme-immunoassay with regard to duration of the test, sensitivity and reading of test results. Test conditions and composition of some components of the test system were modified. With the first modification the test could be performed within 3 h and was about 3X as sensitive as Hepanostika. However, this method was less specific than Hepanostika and it was not suitable for routine screening. A second modification was studied with two differently prepared conjugates. The duration of the test was less than 4 h and the sensitivity was at least twice that of Hepanostika. The test results could be measured directly with a suitable photometer. Preliminary results with more than 500 deep-frozen donor sera showed that the specificity was acceptable with a number of false positives being less than 2%.

Enzyme-Linked Immunosorbent Assay↗
PubMed1979

Detection of human antibodies to hepatitis B surface antigen (HBsAg) by an enzyme-immunoassay for HBsAg.

We studied the feasibility of detecting antibody to hepatitis B surface antigen (anti-HBs) by an inhibition assay using the reagents of an enzyme-immunoassay for HBsAg (Hepanostika). Several modifications of the basic assay were investigated. Sensitivity was greatest when the test sample was incubated with a predetermined amount of HBsAg before the usual procedure of HBsAg detection. The presence of anti-HBs in the test sample was shown by a reduction of the solid-phase bound enzyme label. Results were obtained with a dilution series of serum samples containing anti-HBs, the anti-HBs Reference Panel of the American Bureau of Biologics, sera of hepatitis B patients, and sera of two individuals passively immunised with anti-HBs. The enzyme-immunoassay method showed at least the same sensitivity as passive haemagglutination. It was less sensitive than a commercially available radioimmunoassay (Ausab). There are no indications that non-specific reactions occur frequently. This study also revealed that the antigenaemia of acute hepatitis-B patients can be interrupted by a transient seroconversion.

Acute Disease↗
PubMed1978

Enzyme-immunoassay in diagnosis of hepatitis with emphasis on the detection of "e" antigen (HBeAg).

A brief survey of the application of enzyme-immunoassay (EIA) for the detection of hepatitis B surface antigen (HBsAg), hepatitis A, and their corresponding antibodies is given. The preliminary results of a similar EIA for detection of hepatitis B-related "e" antigen (HBeAg) and its antibody (anti-HBe) are reported. This EIA is much more sensitive than immunodiffusion: at least 128 times for HBeAg and at least 512 times for anti-HBe. HBsAg and its antibody do not interfere with the test. Only a few sera strongly positive for rheumatoid factor gave rise to false-positive results, as was demonstrated by a confirmatory test.

Carrier State↗
PubMed1977

Enzyme-linked immunosorbent assay for hepatitis B surface antigen.

A solid-phase enzyme-linked immunosorbent assay (ELISA), based on the "sandwich" principle with use of microtiter plates, was developed for the detection of hepatitis B surface antigen (HBSAg). Results could be read within one day by the naked eye or by colorimeter. The detection level was less than or equal to 5-10 ng of HBSAg/ml. The sensitivities of ELISA and radioimmunoassay were about the same in dilution series and in a follow-up study of 19 patients with acute hepatitis B infection. In 11 European medical centers where greater than 50,000 samples were tested, ELISA detected significantly more HBSAg-positive samples than a reversed hemagglutinatiom test. No significant difference in sensitivity between ELISA and radioimmunoassay could be demonstrated. On the average, 2.2% of readings were false-positive reactions. Falsely positive samples were identified by a confirmatory test.

Acute Disease↗
PubMed1976

[Complications following ambulatory abortion].

A survey was made of 394 abortions with ensuing complications during the years 1970-1974. Of these 17 were induced abortions, 3 of which showed serious complications. In two of these cases uterus extirpation by laparotomy was necessary.

Abortion, Induced↗
PubMed1976

Solid-phase enzyme-immunoassay for detection of hepatitis B surface antigen.

The preliminary results of a solid-phase enzyme-immunoassay (EIA) for the detection of hepatitis B surface antigen (HBsAg) are presented. This method has been compared with the solid-phase radioimmunoassay (RIA) for HBsAg in dilution series of four HBsAg positive sera four national reference panels (The Laboratory Panel of the Central Laboratory of the Blood Transfusion Service of the Netherlands Red Cross, USA BOB Reference Panels Nos 2 and 3, and the 1st Panel of the National Reference Centre for virus Hepatitis at the Institute of Hygiene of the University of Göttingen, West Germany). In addition, the two test methods were compared in a weekly (up to 16 weeks) follow-up of 14 patients with acute viral hepatitis B. It was seen that, both by reading EIA test results with the naked eye and by colorimetric reading, the sensitivity and specificity of this test method compared very favourably with those of the RIA. EIA may have a slightly lower sensitivity than RIA for the subtype ad, while its sensitivity for the subtype ay may be slightly higher than that of RIA. These minor sensitivity differences may be due to the specificity profiles of the antisera used.

Antibody Formation↗
PubMedDate not supplied

Hepatitis B surface antigen and human serum proteins.

The purification of HBs Ag is briefly discussed with emphasis on the immunochemical characterization of the resulting preparations. Results of experimental work in various laboratories aimed at establishing presence or absence of human serum proteins as integral parts of (highly purified) HBs Ag particles do not yet allow definite conclusions.

Animals↗
PubMedDate not supplied

Results of a multicentre clinical trial of the solid-phase enzyme immunoassay for hepatitis B surface antigen.

The results obtained in a multicentre clinical trial of an enzyme immunoassay (EIA) method for hepatitis B surface antigen (HBsAg) (65,451 sera tested) have demonstrated that this new test has a significantly higher sensitivity than a reversed haemagglutination test (rHA). In a part of the trial, EIA was also compared with radioimmunoassay (RIA). Only a small number of discrepant results was obtained with these two tests, indicating similar sensitivities. No definite conclusion about a difference in sensitivities could be drawn from these results. Although the specificity of the EIA screening test is lower than that of rHA and RIA, the mean percentage of false positives was 2.2% of the total number of donor samples screened. Presumptive positives in EIA were subjected to a confirmatory test based on neutralization with human antibodies to HBsAg. After elimination of false positives in EIA screening, there was excellent agreement between EIA and RIA results.

Blood Donors↗