Acta biologica et medica Germanica最新文献

Several fluorescence assays with bovine leukemia virus (BLV) conjugated to activated Sepharose 4B were used for the detection of BLV and anti-BLV antibodies. These tests were compared with a solid-phase radioimmunoassay and found to be in the same sensitivity range. Sepharose bead immunofluorescence assay and solid-phase radioimmunoassay can be applied to the diagnosis of BLV infection in cattle.

Proteinase B from baker's yeast was purified to homogeneity by applying affinity chromatography with D,L-tyrosine ethyl ester as ligand. The molecular parameters of the product are similar to those reported formerly by other groups. A different form of proteinase B is isolated if affinity chromatography is replaced by CM-cellulose chromatography and gel filtration. In this case a peptide tightly associated with the enzyme was found to occur. This could be identified as an inhibitor fragment produced by limited proteolysis of a proteinase B bound inhibitor induced by proteinase A.

In human diabetes mellitus, functional microangiopathy starts with venule dilatation, the cause of which is unknown. The results of comparative measurements of animals with alloxan diabetes verify also an increase in the arterio-venous calibre relation. As studied vital-microscopically, these alterations are due to venule congestion and passive dilatation as a consequence or red cell aggregation and an increase in the viscosity of blood. The increase of the flow resistance on the postcapillary side depends only on rheological but not on nervous-humoral factors, which leads by means of a veno-arterial reaction to increased constrictions of the arterioles.

Rabbit antisera against specifically purified guinea pig IgG1 and IgG2 antibodies and against several papain-fragments of IgG2 were produced. These antisera were made specific by absorption with purified immunoglobulin of the other subclass and assayed for monospecificity by two immunological tests. In the macrophage rosette inhibition test, only the anti-IgG2 and the anti-Fab (IgG2) sera were effective. Inhibition of the rosette formation could be obtained at dilutions up to 1:100 or higher. Attempts to induce passive cutaneous anaphylaxis in the guinea pig skin after sensibilization with homocytotropic antibodies were evidently positive only with rabbit anti-guinea pig IgG1 serum. Anti-IgG2 and anti-IgG2 Fab sera revealed a positive reaction in higher concentrated forms (1:2 or 1:5 diluted) only.

In accordance with earlier results the electrophoretic mobility of lymphocytes is decreased by horse anti-human lymphocyte globulin (AHLG), which correlates with the results of the rosette inhibition test. Under the influence of AHLG, the distribution of the electrophoretic mobilities of lymphocytes shows a characteristic change. In some of the AHLG samples, the antilymphocyte action is accompanied by an antithrombocyte effect. The resulting decrease in the electrophoretic mobility of platelets correlates with the thrombocytopenic effect in vivo. The variation of pH or ionic strength leads to changes of the AHLG effects. The in vivo influence of AHLG on the distribution of the electrophoretic mobility of peripheral blood lymphocytes and platelets is discussed.

The reduction of Sepharose bound mistletoe lectin I (ML I) is a convenient method for preparing A- and B-chains under mild conditions. The B-chain represents the D-galactose binding moiety. The A-chain shows a significant dose-dependent inhibition of protein synthesis in cell-free systems from rat liver and rabbit reticulocytes, while pure B-chain preparations do not affect ribosomal translation processes.

Bilateral symmetric lesions of the posterior thalamic nucleus reduced the preoperatively learnt avoidance responses in Long-Evans hooded rats strongly. Postoperative acquisition of conditioned avoidance reflexes was rather low in each rat in a simple runway and impossible in an alternation task. Thresholds of reactions to pain (withdrawal of paws from the grid floor) were significantly increased. The lesioned rats had trouble to find the way out, as if they had difficulties to localize the source of punishment or to associate pain information with any other cues.

To determine the possible role of cytochrome P-450 in the adaptation response of an organism to chronic carbon monoxide exposure, rats received 4, 15 or 30 subcutaneous CO injections (7.2 mmol/kg body mass; maximal COHb concentration about 56%). The concentration of cytochrome P-450 is significantly reduced after 4 injections. This effect is no longer evident following 15 or 30 CO injections, which produced distinct increases of the total hemoglobin concentration. Ethylmorphine N-demethylation is distinctly inhibited after 4, 15 and 30 CO injections, whereas the initial inhibition of ethoxycoumarin O-deethylation disappears after 30 CO administrations. Ethoxyresorufin O-deethylation is only slightly influenced by CO.