Alpha-1-Fetoprotein (AFP): international proficiency study with different test systems.

BACKGROUND: The present proficiency study aimed to elucidate the comparability and reliability of test systems for the determination of AFP concentrations. METHODS: 25 laboratories using 8 different commercial test systems used liquid BIOREF-AFP control serum in their routine internal quality control over a period of one year. For statistical analysis the results were collected centrally. RESULTS: The statistical analysis of the test results revealed considerable variation for the different laboratories. The deviations of the mean values of different laboratories from the overall mean value varied between 0.1 and 26.1%, and for most of the laboratories the deviation was round about 10%. The precision of measured values in the individual laboratories was in most cases acceptable: Nevertheless, the coefficients of variation of the individual laboratories ranged from 13 to 16.1%. CONCLUSIONS: In conclusion, this study indicates that AFP results vary between different laboratories albeit an international standard for AFP is available. Therefore, every laboratory should participate in external ring studies and should use a quality control serum independent of the test kit manufacturer for the internal quality control.

[Influencing the fibrinolytic activity by antithrombotics in patients with atherosclerosis]. / Die Beeinflussung der Fibrinolysekapazität durch Antithrombotika bei Patienten mit Arteriosklerose.

In 106 atherosclerotic patients receiving an anticoagulant therapy and 91 patients receiving acetylsalicylic acid, fibrinogen and fibrin degradation products were determined as well as euglobulin lysis before and after venous occlusion. Platelet function data and thromboxane (TXB2) were also determined. Since "moderate" anticoagulant therapy with thromboplastin time values 26-40% results in deteriorated fibrinolysis data, anticoagulant therapy is strictly to remain within the therapeutic range of 15-20% up to 25% thromboplastin time at maximum. Treatment with acetylsalicylic acid proved useful on condition that the required dose was determined individually. This type of treatment will then be able to reduce the thromboxane level and positively influence the fibrinolytic potential.

Determination of serum level of myoglobin and plasma level of autoantibodies to myoglobin in patients with angina pectoris.

The serum level of myoglobin (Mb) was determined in 11 male patients with chronic ischemic heart disease (angiographically studied) by the mean of an enzyme immunoassay (EIA). By a second EIA we could detect in all our patients autoantibodies (autoAB) to Mb. While the level of Mb in all cases was normal (less than 100 ng/ml) we found differences in the level of autoAB to Mb (normal value 90-100%). 7 patients with unstable Angina pectoris exhibited decreased levels of autoAB to Mb (65%). In 4 patients with stable Angina pectoris autoAB to Mb were 93%. The physiological role of the autoAB to Mb remains still unclear. The simultaneous determination of Mb and the autoAB to Mb may be helpful in differential diagnosis of stable and unstable Angina pectoris.

Differences in phosphorylation of isolated phospholamban in dependence on the preparation procedure.

Phospholamban was purified by two different preparation protocols. The products of both preparations are immunochemical similar. They differ, however, with regard to their phosphorylation by the catalytic subunit of cAMP-dependent protein kinase. It is suggested that the lipid environment plays a crucial role in the exposition of the phosphorylation sites of phospholamban.

Purification of phospholamban and characterization of its antibodies.

Phospholamban was extracted from pig heart microsomal membranes with a methanol-chloroform (2:1) mixture. The proteolipid was further purified to electrophoretic homogeneity by chromatography in organic solvents and in SDS-containing medium. Purification was about 50-fold with respect to specific 32P-phospholamban radioactivity. Antisera were produced in rabbits against phospholamban. Electroblot analysis demonstrates specific binding of the antisera to purified phospholamban and to phospholamban in preparations of cardiac sarcoplasmic reticulum and sarcolemma.

[Human T-lymphocytes--clinical and methodological studies on the detection of Fc-IgM- and Fc-IgG-receptor bearing T-lymphocytes (Tm and Tg)]. / Humane T-Lymphozyten--Klinische und methodische Studien zum Nachweis von Fc-IgM- und Fc-IgG-Rezeptor-tragenden T-Lymphozyten (TM und TG).

Several methodical aspects for determination of T lymphocytes with Fc receptors for IgM (TM) and IgG (TG) were studied including separation technique of T cells with E-rosetting, culture conditions of T cells for determination of TM and the rosetting of TM and TG with EA complexes. The bests results were obtained by stabilization of E-rosettes with human serum albumin, after separation of E-rosette forming cells lysis of sheep erythrocytes with save hypotonic shock, culturing of T cells in medium containing 20% AB Serum. Furthermore it was shown the possibility using EA complexes produced with not purifieded IgG or IgM anti-ox-red-blood cells antisera without lost of specifity for TM and TG. The percentage of TM and TG in peripheral blood of thirty healthy persons as well as monitoring TM and TG in three cases was investigated.