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Biomedical subjects

H Claeys

Publications and source records attributed to H Claeys.

16 recordsLinked to original sources
PubMed1992

Association of hepatitis C virus carrier state with the occurrence of hepatitis C virus core antibodies.

An enzyme immunoassay (EIA) was developed for the determination of antibodies against the "putative" core protein of hepatitis C virus (HCV). Antigens used were recombinant fragments (amino acids 6-77 or 6-143) of the HCV core protein, produced in Escherichia coli with truncated hepatitis B core (HBc) as fusion protein. Evaluation of 385 sera positive for HCV antibodies by first generation EIA, revealed 98 (25.4%) with HCV core antibodies. HCV-RNA, determined by the polymerase chain reaction (PCR), was exclusively found in the sera positive for HCV core antibodies (89 PCR positives). In random screening of 3,708 sera, 3 sera with HCV core antibodies were found PCR positive. Only 2 of these sera were positive in the first generation EIA. It is concluded that HCV core antibody determination is a reliable test for identifying HCV carriers among blood donors.

Carrier State↗
PubMed1992

Confirmation of hepatitis C virus positive blood donors by immunoblotting and polymerase chain reaction.

In a series of 385 sera obtained from volunteer blood donors positive for the first-generation hepatitis C virus assay (Ortho), the viral genome was detected by polymerase chain reaction (PCR) in 89 sera (23%). Most PCR-positive sera were found positive with the c100-3 neutralisation assay (Abbott) and by two second-generation enzyme immunoassays (Abbott, Ortho). However overall specificity of these assays was rather low. By immunoblotting (Innogenetics and Chiron/Ortho) the specificity could be considerably improved and the best correlation with carrier state was obtained when analysing the results for lane-specific reaction: all 89 viral carriers and only 9 other donors had antibodies against structural 'core' epitopes. From the present data we can conclude that in screening a volunteer blood donor population the confirmation of antibodies against 'core' epitopes by immunoblotting is strongly associated with viral carriage.

Base Sequence↗
PubMed1986

A microcomputer-based graphical reconstruction technique for serial sectioned objects, with hidden line removal.

The presented software package fulfills the need for processing serial sections with a microcomputer configuration, enabling three-dimensional reconstruction with hidden line removal. The language used is an interpreted BASIC-dialect (HPL). The input is performed via an interactive program. The object can be rotated in space. The Hidden Line algorithm does not depend upon a raster technique. Points of intersection of successive contours are calculated and inserted, thus providing drawings of high resolution and quality. The handling time can be said to be short, especially when considering the capacities of the microcomputer configuration used.

Animals↗
PubMed1986

Transfer factor therapy in multiple sclerosis: a three-year prospective double-blind clinical trial.

One hundred five patients with MS were divided into three groups matched for age, sex, and disability, and treated with either placebo, transfer factor prepared from leukocytes of random donors, or transfer factor from leukocytes of family members living with the patients. There were no differences in the three treatment groups for changes in disability, activities of daily living, or evoked potentials. Eighteen months of transfer factor therapy had no effect on gamma-interferon production or natural killer cell activities.

Activities of Daily Living↗
PubMed1979

Action of brinase on human fibrinogen and plasminogen.

Brinase added to human plasma in vitro caused a decrease in fibrinogen concentration, positive paracoagulation tests and formation of a friable clot in sequence. Agarose gel filtration of these samples revealed the presence of fibrinogen derivatives both larger and smaller than the parent molecule. Infusion of the enzyme in vivo resulted in a decreased fibrinogen level, a prolonged thrombin time and an increase in fibrinogen related antigen (FRA) in serum. The elution pattern of FRA in the plasma samples obtained after infusion of Brinase was similar to that of the in vitro samples. The plasma pool of fibrinogen was partially consumed by infusion of Brinase, but the turnover of plasminogen remained unaffected. Purified plasminogen was partially degraded by addition of the enzyme but this was accompanied by a generation of proteolytic activity. These findings confirm that Brinase induces a proteolytic degradation of fibrinogen in plasma without activation of the plasminogen-plasmin system. Exposure of polymerization site(s) in the fibrinogen molecule is probably responsible for the reported clot promoting effect of the enzyme.

Antigens↗
PubMed1975

Amino-acid sequence of activation cleavage site in plasminogen: homology with "pro" part of prothrombin.

A 38-residue fragment is isolated from carboxymethylated plasminogen. Residues 29-38 have the same sequence as the amino-terminal end of the light chain of plasmin. The sequence 1-28 is therefore the sequence of the carboxyl-terminal end of the heavy chain and contains the specific sequence at which urokinase (EC 3.4.99.26) and other plasminogen-activating serine proteases split. Two of the five carboxymethyl-cysteine residues in the isolated fragment are situated close to the cleavage site and the fragment is not itself a substrate for plasminogen-activators. Residues 1-11 show extensive sequence homology with residues 137-147 and 242-252 in prothrombin, which are located in corresponding regions of the two internally homologous 83-residue structures in the non-thrombin part of the molecule, indicating that such structures may be a common feature of the non-protease part of the larger serine protease zymogens.

Amino Acid Sequence↗
PubMed1972

Metabolism of plasminogen in healthy subjects: effect of tranexamic acid.

The metabolism of human plasminogen labeled with radioactive iodine was studied in 12 healthy men. The labeled plasminogen had a high specific activity and the same elution on Sephadex G-100 as the plasminogen activity in plasma. Immunoelectrophoresis revealed a single precipitin line. Polyacrylamide gel electrophoresis revealed six main bands, all with plasminogen properties and radioactivity. The purified plasminogen behaved as a homogeneous protein in the turnover experiments. The plasma radioactivity data were adequately approximated by a sum of two exponential terms. The metabolism of plasminogen was therefore represented by a two-compartment mammillary model. Results in the 12 normal subjects were as follows: plasma plasminogen concentration 20.8+/-1.9 mg/100 ml; intravascular plasminogen pool 0.66+/-0.14 g; intravascular fraction 0.59+/-0.06; fractional catabolic rate 0.55+/-0.09 of the plasma pool per day; half-life of the plasma radioactivity 2.21+/-0.29 days. Circulating large-molecular-weight degradation products of labeled plasminogen could not be detected by Sephadex G-100 gel filtration. The plasminogen turnover rate was normal in a patient with Behçet's syndrome and low circulating plasminogen activator activity. This finding supports the concept that under normal conditions the primary pathway of plasminogen catabolism is not via the formation of plasmin. The in vivo effect of tranexamic acid, a potent inhibitor of plasminogen activation, on the turnover of labeled plasminogen was studied in five normal subjects. When 1 g was administered perorally t.i.d. to three of them, one showed an increased plasminogen turnover. A 2 g dose administered t.i.d. to the other two caused markedly increased catabolism in both. This increase may be attributable to a direct reversible effect of tranexamic acid on the plasminogen molecule.

Acrylamides↗