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Biomedical subjects

W Vogt

Publications and source records attributed to W Vogt.

At least 145 records · Page 8Linked to original sources
PubMed1977

[The mechanization of the enzyme immunological determination of phenytoine with the Centrifichem (author's transl)].

The separation of free from bound antigen is not required in homogeneous enzyme immunoassays (EMIT). Therefore this technique can easily be mechanized. For the mechanization of the enzyme immunological determination of serum levels of Phenytoine the fast analyzer (CENTRIFICHEM) was found most satisfactory in our laboratory. The marked advantages over manual methods are: 1. The amount of sample and reagents needed can be reduced by half. 2. The intra- and interassay variance are significantly better compared to values found with manual techniques. 3. 60 samples can be determined in duplicate in under two hours.

Autoanalysis↗
PubMed1976

[Significance of serum digoxin concentration and its influencing factors].

In recent years it has become possible by means of a radioimmunoassay to measure Digoxin concentration in the serum of digitalized patients. With this method it could be shown that the resorption of Digoxin is decreased by partial resection of the samll intestines, by malabsorption syndromes, after ingestion of Neomycin, Colestyramine and antacids. In renal insufficiency, however, the elimination half-life period of Digoxin is increased conspiciously (from about 35 hours up to about 120 hours). This results in a raised serum concentration of cardiac glycosides unless the dosage is decreased considerably. The incidence of Digitalis intoxication in Digitalis treated patients has been reported to rank as high as 20%. There is, however, no strict correlation between the serum glycoside level and the clinical symptoms, because the glykoside concentration in the serum does not represent the pharmacologically active concentration at the receptor. Experimental investigations of cardiac glycoside binding to the receptor for cardiac glycosides in human heart cell membranes revealed, that receptor bound Digoxin for instance is diminished in serious renal insufficiency and it depends on the serum concentration of potassium, calcium and magnesium. In hypoxia, after myocardial infarction and in myxedema the sensitivity for cardiac glycosides is increased. The opposite is true in hyperthyreoidism, fever and in children. All of these factors have to be kept in mind and paid attention to in the clinical evaluation of the measured Digoxin concentration in the serum.

Cardiac Complexes, Premature↗
PubMed1976

Steroid phosphorus compounds. V--Mass spectrometry of phosphinic esters of monohydroxy steroids.

The mass spectra of the dimethylphosphinic, dimethylthiophosphinic and dimethylphosphinous ester derivatives of several monohydroxy steroids are reported. The fragmentations of the derivatized steroids largely depend on the nature of the phosphorus-containing ester group. Phenolic ester derivatives exhibit the base peak at the molecular ion, whereas the spectra of the secondary phosphinic esters are dominated by very intense protonated phosphinic acid ions [Me2P(XH)(OH)]+ at m/e 95 (X =O) or at m/e 111 (x = s). The present results also indicate the low ionization potential for the phosphinic ester group. Due to their good gas chromatographic properties, these steroid derivatives appear to be particularly suitable for gas chromatographic mass spectrometric analysis of biochemical materials.

Androsterone↗
PubMed1976

Effect of hog anaphylatoxin (C 5a) on vascular permeability and leukocyte emigration in vivo.

The effects of highly purified hog anaphylatoxin (C 5a) on leukocyte emigration were investigated in guinea pigs in vivo using two experimental models: 1. Subcutaneous infusions. Sterile solutions of C 5a in saline infused at a rate of 1.8 mug C 5a/h (0.2 ml/h) for 10 h induced a dense accumulation of leukocytes, mainly neutrophils but also some eosinophils at the site of application; In control infusions with saline alone comparatively few leukocytes were found. 2. Single injections into the pleural cavity. 10 or 20 mug C 5a (dissolved in 2 ml saline) caused a dose-dependent increase in leukocyte number and volume of pleural exudate. Bradykinin in a dose of 18 mug produced similar fluid exudation as 20 mug C 5a but had no significant effect on leukocyte accumulation. Intrapleural injections of C 5a further caused the appearance of i.v. injected Evans blue in the pleural cavity. This effect, indicating an increase in vascular permeability lasted for about 3 h; Since at least one of the two models used - subcutaneous infusion -simulates natural conditions -continuous local generation of C 5a in small amounts at the site of an inflammatory lesion-the results indicate that C 5a once formed by complement activation in natural defense reactions may contribute to local increase in vascular permeability and leukocyte infiltration.

Anaphylatoxins↗
PubMed1976

Induction of platelet aggregation by the complement-derived peptides C3a and C5a.

The effect of two complement-derived peptides, hog serum C3a and C5a, on platelet aggregation in platelet-rich plasma and suspensions in Tyrode solution was investigated. 1. Guinea-pig platelets were aggregated by both C3a and C5a; the spasmogenically inactive product of C3a, C3ai, also induced aggregation. Threshold concentrations were in the range of 10(-6)--10(-9) M depending on the peptide and platelet preparation. 2. Cat platelets were aggregated by C5a (threshold concentrations 10(-7)--10(-8) M) but not by C3a. 3. Platelets from pig, rabbit and man were not aggregated by either of the two peptides in concentrations of up to 5 X 10(-6) M. 4. When C5a was administered repeatedly in subthreshold doses guinea-pig platelets became tachyphylactic to C5a but were still aggregable by C3a or ADP. Conversely, platelets desensitized to C3a still reacted to C5a or ADP. Tachyphylaxis towards C5a developed also when platelets were incubated with C5a in the absence of free Ca2+ under which condition they do not react. The tachyphylaxis in this case became evident after recalcification of the medium. The lack of cross-desensitization indicates that C3a and C5a react via different receptors. 5. C3a and C5a were injected i.v. into guinea pigs. Histological examination of the lungs revealed that some of the smaller vessels (20-30 mu in diameter) were occluded by platelet aggregates. In addition signs of severe acute emphysema were seen in animals treated with C5a, but only slight emphysema in C3a-treated animals. Intravenous injections of C3a into guinea pigs caused but weak respiratory distress and drowsiness and never killed an animal (at doses of up to 20 mg per kg body weight), whereas C5a caused the well-known severe respiratory failure and death already at doses of 0.03 mg/kg body weight.

Anaphylatoxins↗
PubMed1976

Purification and some properties of factor D of the human properdin system.

Factor D has been purified by gel and ion exchange chromatographies, and by ultrafiltration through different membranes. The final preparation appeared pure in various analytical tests. The molecular weight of human D is 21,500 according to gel chromatography, the isoelectric point was found at pH 7.8. Factor D is an active esterolytic enzyme, it cleaves N-alpha-acetyl-L-lysine methyl ester and N-alpha-acetyl-L-glycyl-L-lysine methyl ester. Both peptide esters inhibit the hydrolytic activation of factor B by D in the presence of cobra venom factor. D is also inhibited by diisopropyl-fluorophosphate and by penylmethyl-sulfonyl-flouride.

Humans↗
PubMed1976

Purification of a human serum protein ("factor E") which enhances cobra venom factor-induced indirect lysis. Identification with the fifth component of complement.

Complexes formed of Cobra venom factor (CVF) and activated factor B (B) by interaction of CVF and B with trypsin or factor D are capable of activating the third and fifth complement component. When incubated with sheep or guinea pig red cells and guinea pig serum in the presence of EDTA, these CVFB complexes produce "indirect lysis". Addition of a human serum factor, earlier designated as factor E (6), greatly enhances the efficiency of this lytic system. The component with this activity has been purified to homogeneity (disc and immunoelectrophoresis). In chromatographic fractionations it was inseparable from the fifth complement component, it was inactivated by and reacted with several anti-C5 antisera, and kinetics of inactivation by heat (56 degrees C) and trypsin were the same for factor E and hemolytic C5 activities. It is concluded that factor E is the fifth component of human complement. Guinea pig C5 is not capable of supporting indirect lysis in a comparable manner, for as yet unknown reasons. Some possible explanations are discussed.

Animals↗
PubMed1976

Incompatibility between C3b and B of guinea-pig and man and its influence on the titration of the alternative pathway factors D and B in these two species.

The incubation of the proteins C3b, B, D and C3 induces enzymatic activation of B and of C3. This system of purified components was applied to the titration of the guinea-pig and human factors D and B in various homologous and heterologous reaction mixtures. On the basis of functional as well as of immunological tests, the D enzymes of both species were found to be related proteins. First, titrations of factor B revealed that both D enzymes activate homologous and heterologous B with comparable efficiency. Secondly, a rabbit anti-D antiserum raised against guinea-pig D was found to form a precipitation line of partial identity with guinea-pig and human D. In contrast to the compatibility between heterologous D and B, heterologous combinations of C3b and B were found to be incompatible. This incompatibility was indicated by low titres of D in the presence of heterologous C3b and B; in contrast, in the presence of homologous C3b and B, the titres of D were up to one hundred-fold higher. The reason for this effect was found to reside in inefficient complex formation between heterologous C3b and B. Therefore titrations of D and B should be only performed in the presence of homologous C3b and B.

Animals↗
PubMed1975

[Effect of aprotinin in acute myocardial infarction (clinical double-bind study (author's transl)].

In a double-bind study 164 patients with acute myocardial infarction, admitted to an intensive-care unit within 72 hours of infarction, were randomly treated for three days either with aprotinin (Trasylol-82 persons) or placebo (82 persons). Retrospective analysis proved both patient groups to have been comparable in all other respects. There was no definite influence on the course of the infarction, haemodynamic changes, arrythmias or mortality rate. Trasylol thus has no therapeutic importance in the treatment of acute myocardial infarction.

Acute Disease↗
PubMed1975

Histamine release, formation of prostaglandin-like activity (SRS-C) and mast cell degranulation by the direct lytic factor (DLF) and phospholipase A of cobra venom.

Cobra venom, alone and in combination, on mast cell degranulation, histamine release and formation of prostaglandin-like activity (SRS-C) was studied in perfused guinea-pig lungs and in mast cell-containing rat peritoneal cell suspensions. For comparison, the effect of equivalent doses of whole cobra venom was investigated. 1. Cobra venom caused mast cell degranulation, histamine release and SRS-C formation in both systems. For comparable effects much higher doses had to be used in guine-pig lungs than in rat peritoneal cell suspensions. 2. Phase A showed little degranulation of mast cells in both systems, a limited histamine release in rat peritoneal cell suspensions and none in perfused guinea-pig lungs. It caused a considerable SRS-C formation in both, lung tissue and peritoneal cell suspensions. 3. DLF caused histamine release, SRS-C formation and mast cell degranulation in both systems; in rat peritoneal cell suspensions it acted almost as strong as equivalent doses of cobra venom, in guinea pig lungs it was much less active. 4. In rat peritoneal cell suspensions the effects of DLF and phase A in combination did not exceed the sum of their single effects. In guinea-pig lungs these two substances interacted in a potentiating synergism. It is concluded that DLF is the main cytotoxic principle of cobra venom, whereas ph-ase A alone is not cytotoxic. The difference in the synergism of DLF and ph-ase A between rat peritoneal cells and guinea-pig lungs may be due to two different actions of DLF and species differences as regards sensitivity against these actions.

Animals↗