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Biomedical subjects

W Kramer

Publications and source records attributed to W Kramer.

At least 199 records · Page 11Linked to original sources
PubMed1980

Induction of prostaglandin E release from macrophages by colchicine.

Rat peritoneal macrophages released high amounts of prostaglandin E (PGE) when treated in vitro with 10(-7) to 10(-4) M colchicine. PGE production occurred after a lag period of 4 hr and proceeded at a constant rate for more than 24 hr. Lymphocytes could not be stimulated to PGE release by colchicine. Disaggregation of microtubules appeared to be an essential event, since lumicolchicine was inactive and addition of heavy water (D2O) abolished colchicine-induced PGE formation. Cytochalasin B (5 microgram/ ml) did not interfere with PGE production by colchicine during the initial 12 hr, but thereafter it gave rise to an activity capable of degrading or converting newly synthesized PGE. Although details of the mechanisms by which colchicine in association with disrupted microtubules may induce PGE release remain unclear, these observations suggest that components of the cytoskeleton may efficiently influence the biosynthesis of prostaglandins.

Animals↗
PubMed1980

[Echo parameters of chronic aortic regurgitation (author's transl)].

Staging and timing of aortic-valve replacement, with respect to long-term prognosis is crucial in patients with isolated chronic aortic regurgitation (AR). To compare angiographic and M-mode echocardiographic parameters we echoed 39 patients one day before cardiac catheterisation: The angiography was used to divide the collective into four grades (G I-G IV). End-diastolic volume (EDV), stroke volume (SV) and regurgitant volume (RV) were used as echo parameters of the left ventricular volume, ejection fraction (EF) and circumferential fiber shortening (VCF) as parameters of left ventricular function. AR of G II and G III could be differentiated by an increase of EDV from 145 +/- 28.2 to 304 +/- 33.5 ml (p < 0.001), whereas EDV in G I-G II were similar to normal and G IV was similar to G III. EF and VCF were able to differentiate G III and G IV by a decrease from 67 +/- 8% to 54 +/- 7% (p < 0.001) and 1.01 +/- 0.24 to 0.88 +/- 0.31 (p < 0.01) respectively. Thus echo measurements predicted AR greater than G II from an increase of the EDV by more than 110% and a regurgitant volume of more than 3 1/min. G III and G IV could be differentiated by EF und VCF. These quantitative echo parameters were highly sensitive (92%) and specific (96%) whereas all other M-mode echo signs (oscillations of the mitral valve leaflet and interventricular septum, amplitude of oscillations, aortic root diameter, diastolic separation of the cusps) could be used only as qualitative indices, some with high specificity. Echocardiography allows a non-invasive assessment of the severity of AR based on parameters of left ventricular volume and function and thereby assist the accurate timing of aortic valve replacement.

Adult↗
PubMed1979

Bile salt binding to serum components. Taurocholate incorporation into high-density lipoprotein revealed by photoaffinity labelling.

1. Photoaffinity labelling of human serum albumin with the sodium salts of (3 beta-azido-7 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oyl)-2-amino[2(-3)H (N)]ethanesulfonic acid, (7,7-azo-3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oyl)-2-amino[2(-3)H (N)]ethanesulfonic acid and (11 zeta-azido-12-oxo-3 alpha,7 alpha-dihydroxy-5 beta-cholan-24-oyl)-2-amino[2(-3)H (N)]ethanesulfonic acid resulted, in each case, in a considerable covalent incorporation of radioactivity into the protein. 2. Photoaffinity labelling of whole serum, obtained from fasting test persons, revealed with all three photolabile derivatives of taurocholate at the physiological concentration of 2.1 microM the incorporation of radioactivity not only into albumin but also into high-density lipoprotein, as demonstrated by density gradient centrifugation and by immunological characterization. 3. The bulk of radioactivity incorporated into high-density lipoprotein by photoaffinity labelling of whole serum was found to have been associated with the lipids. Only 10-20% of the label was covalently bound to apolipoproteins, predominantly to the apolipoproteins A-I and A-II. 4. The interaction of taurocholate with high-density lipoprotein has been confirmed by density gradient centrifugation using 14C-labelled taurcholate. It is assumed that the interaction of taurocholate with high-density lipoprotein is physiologically of significance.

Adult↗
PubMed1979

Antiphytoviral activity of 2,4 dioxo hexahydro triazine.

Three treatments with 2,4 dioxo hexahydro triazine (DHT) significantly reduced the concentration of potato virus X (PVX) in systemically infected tobacco plants. In hypersensitive plants DHT caused a reduction in the number of local lesions produced by PVX. In systemic and hypersensitive hosts, treatment with DHT resulted in a more or less marked reduction in the concentration of, and in the number of local lesions caused by, potato virus Y (PVY), potato virus A (PVA), tobacco mosaic virus (TMV), and cucumber mosaic virus (CMV). Three days after treatment with DHT the incorporation of 32P into TMV RNA was significantly reduced, while that into host RNA was less affected.

Antiviral Agents↗
PubMed1979

[Dioxohexahydrotriazine, a new synthetic antiphytoviral compound (author's transl)].

This paper reports the first results of studies made to determine the antiviral activity of dioxo hexahydro triazine, a newly developed antiphytoviral compound. After treatment with dioxo hexahydro triazine, the concentration of helical potato virus X in leaves of Nicotiana tabacum "Samsun" was found to be considerably reduced in both the serological test and local lesion test conducted on Nicotiana glutinosa at temperatures of 14 degrees C +/- 3 degrees C. In secondarily infected leaves, the reduction of the concentration of potato virus X in the range of from 1 mol/l to 10(-3) mol/l was so that it was no longer possible for viruses to be detected serologically. In vitro, however, dioxo hexahydro triazine, which was added to the inoculum, did not produce a significant change in the activity of the virion of potato virus X. Therefore, it is reasonable to assume that dioxo hexahydro triazine tends to affect replication steps of viruses. The use of dioxo hexahydro triazine also had the effect of greatly and highly significantly reducing the concentration of the isodiametric cucumber mosaic virus.

Antiviral Agents↗
PubMed1976

Effect of platelet antiserum on the precipitation of soluble fibrin by endotoxin.

Rabbits were injected with a platelet antiserum to examine the role of thrombocytopenia of the precipitation of soluble fibrin by endotoxin.dotoxin. Platelet antiserum removed more than 98% of the circulating platelets, and the resulting thrombocytopenia with platelet counts below 10,000 per mul persisted during the entire 10 hr-period of the experiment. Leukocyte counts were not significantly influenced by the platelet antiserum. Since the rabbits were treated with high doses of heparin, activation of intravascular coagulation by the antiserum did not occur. Precipitation of soluble fibrin was achieved by injection of endotoxin into rabbits with ancrod-induced circulating soluble fibrin. Thrombocytopenia did not prevent the occurrence of glomerular microclots after ancrod and endotoxin administration. On the contrary, if endotoxin was injected into antiserum- and heparin-treated rabbits with circulating soluble fibrin, glomerular microclot formation occurred even in a higher percentage than in control rabbits treated with absorbed platelet antiserum. This investigation indicates that platelet antiserum-induced thrombocytopenia does not protect against precipitation of soluble fibrin by en

Ancrod↗