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Z Frühbauer

Publications and source records attributed to Z Frühbauer.

16 recordsLinked to original sources
PubMed1990

[Determination of antitoxoplasma IgM antibodies using the ELISA method].

The described ELISA method was developed for the examination of antitoxoplasmatic IgM. It is a double, i.e. 4-layer sandwich with the following layers: 1. anti. IgM antibody, 2. the examined serum in a uniform dilution of 1:100, 3. antigen + antitoxoplasmatic conjugate, 4. combined in a mixture prepared in advance. Thus the reaction is shorter but also more sensitive. The components in all three steps are combined for one hour at 37 degrees C. The entire process takes four hours. With regard to the course of the final answer in this type of ELISA reaction it is better to express the results by the level of the attained plateau of optic density than by a titre. The sera are thus examined in a uniform dilution of 1:100 and the results are expressed by a coefficient, the ratio of optic density of the examined serum to the optic density of the pooled negative control serum. By this evaluation the deviation of the mean is reduced to one half, i.e. V = 12.6%. The coefficient does not depend on the contents of specific IgM in a linear fashion, but an antibody change of 1:2 changes it about 1.55 times.

Animals↗
PubMed1990

[Interpretation of antitoxoplasma antibody findings].

Between reactions assessing one class of immunoglobulins and reactions detecting all serum immunoglobulins comprehensively such as CFT, there is, as might be expected, a very poor quantitative correlation and thus in individual sera the result of one reaction cannot be reliably added to the result of another (CFT:ELISA/IgG). Even the correlation between reactions focused on the same Ig class (ELISA/IgG: IFT/IgG) is no better. Among reactions assessing specific IgM we consider ELISA/IgM better than IFT/IgM because there is not the risk of false negativity caused by concurrence of IgG. A combination of ELISA/IgG and ELISA/IgM gives good results as a statistical group: the distribution of results revealed agglomerations of sera corresponding to the assumed age of the infection derived from the generally accepted pattern of antibody formation. The applicability of the combination of these two reactions alone for evaluation of individual sera is a promising procedure but awaits further confirmation. Long-term investigations revealed within two years after infection a marked decline of CFT antibodies in the majority of cases but it was not sufficiently clear in ELISA/IgG. Despite the technical advantages of ELISA reactions, elimination af the CFT reaction is not foreseen in the near future. As the minimal combination of methods which provides adequate information we may consider at the present time CFT for assessment of total antibodies and ELISA/IgM for more marked differentiation of the acute stage. Evaluation of the lowest CFR titres considered hitherto as "practically negative" must be obviously revised in subjects with immunosuppression and organ donors for transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Determination of antitoxoplasma IgG antibodies using the ELISA method].

The described ELISA reaction is suggested as a method for examination of antitoxoplasmatic IgG antibodies. It is a simple, i.e. three-layer sandwich with the following layers: 1. antigen 2. the examined serum either in serial dilution or single dilution 1:300 and 3. a peroxidase anti-IgG conjugate with a final conclusive step, i.e. a substrate solution with OPD. Sera and conjugate are allowed to bind for 30 mins. at 37 degrees C and the substrate solution with OPD is allowed to act for 15 mins., also at 37 degrees C, and thus the entire reaction lasts about two and half hours. The authors describe alternative procedures with standard serum of a known number of international units (I.U.) or without it, evaluated optically or by a photometer. In the version with standard serum evaluated optically we compare the different localization of equally stained wells in the series of serially diluted (4n) examined and standard serum and thus we assess, based on the different dilutions the number of I.U. in the examined serum. If we compare the sera with the serum standard by means of a photometer, we examine them in a single dilution of 1:300 and compare the resulting optical density (OD) with the calibration curve made with four dilutions of the standard. The calibration curve is plotted on a scale which straightens it approximately at an angle close to the optimal 45 degrees and which makes it possible to take readings of interpolated international units.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Standardization of plates used in the ELISA reaction].

The results of ELISA reactions made on the entire area of the plates, in the same way in all wells revealed that it is essential to eliminate the marginal rows. Even then there are in some instances deviations from the mean. These deviations frequently follow a loop-sided or dish-like pattern with the minimum in the centre of the plate. The deviations equalled in different wells on average 5-10% (or 20%) of the optic density. Between individual rows there may be a 0.100 difference in optic density, in rare instances as much as 0.300. These differences may influence the results during dilution of sera in a series more detailed than 4n and also when examining a single dilution of sera repeated in an inadequate number of wells.

Enzyme-Linked Immunosorbent Assay↗
PubMed1989

[Antitoxoplasma serum--derivation of the national standard (ELISA)].

When assessing the content of specific antibodies in serum there is tendency to abandon the specification expressed as dilution and use more reproducible data, i.e. international units. To this end it is necessary to derive from the international standard the national standard according to which positive control sera in diagnostic sets, produced by SEVAC can be described in international units. In pooled positive human serum recommended as the national standard and in the international standard first the parallel course of the dose/response curve was tested. Then both sera were repeatedly compared: into a close dilution series of the national standard one dilution of the international standard was included and in both sera the dilution with same response was found (by optic density) and thus the activity of the suggested national standard was assessed as 2400 units/ml. The author discusses also the recommended routine procedure for expressing the activity of the examined sera in international units.

Animals↗
PubMed1989

[Detection of Toxoplasma antibodies using the c-ELISA method].

Sensitive and high capacity ELISA techniques introduced for the detection of toxoplasmatic antibodies so far do not correlate very well with standard serological examination systems used in common diagnosis of Toxoplasmosis. The most frequently used method in the CSSR - SFT using tween-ether soluble antigen extract, and displaying very satisfactory agreement with the Sabin-Feldman test, was compared with the system of direct ELISA, using the same antigen extract and the described c-ELISA method. The latter method uses for antibody detection whole non-disintegrated formol-treated trophozoites of Toxoplasma gondii and thus in the reaction in particular membrane antigens, incl. latent ones, are involved. Parallel examination of 160 sera of subjects with clinical suspicion of toxoplasma infection by the standard CFT, method and methods ELISA and c-ELISA revealed a better correlation between CFT and c-ELISA (r = 0.8031) than between CFT and ELISA with soluble antigen (r = 0.6016). Other positive specific features of the c-ELISA method are the use of commercially produced antigen for the immunofluorescence test, considerable elimination of selective adsorption of the polystyrene carrier and the perspective of the long-term preservation of plates with the fixed antigen.

Animals↗
PubMed1979

Verification of tween-ether antigen for complement fixation test in the diagnostics of toxoplasmosis.

Tween-ether toxoplasma antigen for the complement fixation test was verified on a more extensive clinical material. From a series of 949 patient's sera, positive reaction was obtained in 44% of samples with the tween-ether antigen and in only 33.5% of samples with the FT antigen. All sera, giving positive results only with the tween-ether antigen, were also positive in the Sabin-Feldman test. The authors believe that by using this type of more sensitive antigen, containing also the cell-wall components of Toxoplasma gondii, it would be possible to standardize serological examination by the complement fixation test on the basis of an international standard serum.

Animals↗