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Biomedical subjects

L Simek

Publications and source records attributed to L Simek.

At least 19 recordsLinked to original sources
PubMed1988

The first clinical trial for determination of alpha 1 fetoprotein by means of Sevatest-ELISA AFP Kit (micro I).

At the Institute of Sera and Vaccines, Praha, was invented and tested on clinical samples a kit for detection and quantification of alpha 1 fetoprotein in human serum. It is a heterogeneous EIA on the "sandwich" principle. Rabbit antibody to alpha 1 fetoprotein (further AFP) was used for coating the solid surface and goat horse-radish peroxidase labelled antibody to AFP was used as the tracer. Microtitration plate of Czechoslovak manufacture (KOH-I-NOOR, Dalecín) type P with 96 wells was used as the solid phase. The range of an approximately linear part of the calibration curve was intentionally chosen between 10 and 400 ng/ml, since in this way it fills the detection gap in AFP determination between 10 and 200 ng/ml, which is, on the one hand, a physiological value of AFP in human serum and, on the other hand, the bottom limit of sensitivity of counter immunoelectrophoresis (CIEP). Attention was devoted both to reproducibility of the method, i.e. results of intra- and interassays, and comparability with other foreign ELISA Kits. According to the correlation analysis, the kit was ascertained to be very well comparable with kits of foreign provenance. The coefficient of variation (CV) for the interassays varied between 11 and 16% and for intraassays it equalled 15%.

Clinical Trials as Topic↗
PubMed1984

Particulate protein-synthesis factors associated with translatable mRNA in mouse hybridoma cells.

Besides of mRNA, the postribosomal pellet of mouse hybridoma cells contains RNA species which become labeled more rapidly than rRNA. Their synthesis is inhibited by actinomycin D. Density-gradient centrifugation of the postribosomal pellet yielded fractions of approx. 55-60 and 90S, synthesizing after the addition of both ribosomal subunits and energy-sources light and heavy chains of immunoglobulin, as demonstrated by indirect immunoprecipitation. Analysis of translation products by electrophoresis indicated the presence of precursors of mRNAs for immunoglobulin chains in these particles. Postribosomal pellets thus apparently contain different particles composed of similar polypeptide chains and containing protein-synthesis factors associated with translatable mRNA.

Animals↗
PubMed1982

Complexity of the genetic control of a structural marker in the CH1 homology region of pig IgG.

The occurrence of two variant peptides P1 and P2 originating in the vicinity of the heavy-light chain disulphide bridge in the CH1 homology region was examined in IgG samples prepared from 36 randomly selected pigs. The peptides labelled with 35S at the half-cystine residues were separated on two-dimensional peptide maps and their ratio was quantitatively evaluated by a non-destructive automated method using semiconductor detectors. Fourteen individuals were found to yield only the peptide P1, the remaining 22 individuals yielded both P1 and P2 with a mean ratio of 69.4: 30.6. A model of genetic determination of the amino acid interchange, serine-leucine, distinguishing the peptides P1 and P2 was suggested. It has been assumed that the gene for one gamma-chain subclass exists only in the form coding for the peptide P1 whereas the gene for another gamma-chain subclass exists in two allelic forms coding for either P1 or P2.

Animals↗
PubMed1977

[About the elimination of thromboagglutinins from anti-lymphocytic serum (author's transl)].

The possible utilization of the effect of immunological tolerance for inhibition of formation of thromboagglutinins was studied, which dependent of the kind of antigen employed for immunization more or less contaminate antilymphocyte sera (ALS) or globulins (ALG). In the sera of pigs weighing 80-90 kg, immunized with human thrombocytes the thromboagglutinin levels in a) animals tolerated in adult age with an i.v. dose of 2.2 X 10(9) thrombocytes though the complete inhibition of thromboagglutinin formation failed even in these conditions. The attempted induction of tolerance in adult animals, similarly as in newborn piglets obtaining a dose of 1 X 10(9) thrombocytes, was of little success. Good results were recorded in animals tolerated in the perinatal period with a dose of 5 X 10(9) thrombocytes though the complete inhibition of thromboagglutinin formation failed even in these conditions. The authors suggest that of all possible methods for thromboagglutinin elimination, for ALS production the above technique, i.e. the induction of tolerance during the perinatal period seems most feasible, both from the viewpoint of effectiveness and thrombocyte consumption as well.

Agglutinins↗
PubMed1976

[On the production of anti-human-lymphocyte serum (ALS) by means of combined local and intravenous immunization in swine].

Lymphocytes of donors' peripheral blood were used for the study of pig antihuman ALS preparation by means of local and intravenous immunization. The results were compared with those obtained with exclusively local application of the same antigen. Antisera were tested from the aspect of activity (lymphoagglutination, lymphocytotoxicity, the rosette inhibition test) and for the presence of unwanted antibodies (haemagglutinins, thromboagglutinins, precipitins to serum proteins). Of all alternatives tested the following scheme proved to be optimal: subcutaneous application of 2 X 10(9) lymphocytes with adjuvans on day 0, followed by intravenous application of the same dosage on day 13, and serum harvesting on day 20. Antisera thus obtained displayed titres 1: 32 000 to 1 : 130 000 in the RIT - this being maximum level reached by exclusively local immunization only in some animals. Therefore, favourable immunosuppressive effect in vivo can be expected. Even more profound difference was observed in the level of unwanted antibodies that were found to be on markedly lower level after combined immunization. There is a good reason to suppose that with the help of further techniques, more likely absorption, these can be lowered to acceptable level. It is apparent from the results that with the help of a suitable immunization procedure not only highly active ALS can be obtained but also formation of nondesirable antibodies can be suppressed and, despite their thrombocyte contamination peripheral blood lymphocytes can successfully be used.

Animals↗
PubMed1975

[Studies on the production of anti-human-lymphocyte serum (ALS) in bulls].

The applicability of bulls as productive animals was considered for the preparation of anti-humans ALS. The course of immunologic response was studied by lymphoagglutination, lymphocytotoxicity, rosette inhibition, hemagglutination tests and by precipitin formation in two experimental groups immunized by different amounts of lymphocytes from peripheral blood of normal donors. The animals were found to respond well already after the second application of very small amounts of antigen (on day 0-4 times 10(7), on day 21-2 times 10(8) lymphocytes). They showed lymphoagglutination titre 1 : 512-2000, lymphocytotoxic titre being higher than 1 : 4000 and the rosette inhibition test gave a minimum titre of 1 : 65000. On the other hand, further application of a high amount of antigen (2 times 10(9), or 4 times 10(9) lymphocytes) did not lead to further increase in the titre; on the contrary - hyperimmunization resulted in a lower titre in the case of the rosette inhibition test, which is known to correlate best with the in vivo immunosuppressive activity. The hemagglutinin titre was also acceptable under the above conditions and the formation of undersirable precipitins against human serum proteins was negligible. Good response reached by a simple and economical immunization scheme speaks for the suitability of bulls for the production of ALS.

Animals↗
PubMed1975

[Use of the immune tolerance induction in the production of an antilymphocyte serum (ALS) free of antibodies against serum proteins].

The possibility has been investigated of a direct gain of ALS free of undesirable antibodies against serum proteins by inducing immunologic tolerance in productive animals (pigs). Preliminary experiments made with tolerogenic amounts of 10 and 50 ml of sera and with immunization by the serum alone proved applicability of this method. Electrophoresis showed antibodies against 6 to 7 and 2 to 3 fractions in animals tolerated with 10 and 50 ml respectively, compared to 18 to 20 fractions in the control group, which was not tolerated. This has been confirmed when preparing ALS in practice, where the toleration was carried out with 25 ml of serum or with the same amount of serum with the addition of hemoglobin and immunization by lymphocytes isolated from peripheral blood. Final ALS of untolerated animals contained antibodies against 7 to 8 fractions, whereas that of experimental group tolerated with serum and Hb was free of antibodies against serum protein, hemoglobin included. ALS of the group tolerated with normal serum contained only antibodies against hemoglobin. In vitro tests (i.e. lymphoagglutination t., lymphocytotoxicity t., rosette inhibition t.) proved that by inducing tolerance towards serum protein the activity of ALS was in no was affected. According to the results this method can be employed not only for the preparation of ALS, but also for other purposes, such as preparation of monovalent antisera for immunoelectrophoresis.

Agglutinins↗