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Biomedical subjects

D Seiffge

Publications and source records attributed to D Seiffge.

42 records · Page 3Linked to original sources
PubMed1977

On the growth of Brucella species in presence of erythritol in defined and undefined media and amniotic fluid of human, cow and sheep.

Different concentrations of erythritol (25-1000 microng/ml) in defined medium were shown to enhance the growth of 75.00 to 91.66 per cent of Brucella abortus and 69.23 to 100.00 per cent of Brucella melitensis strains studied. Compared to these figures only 13.04 to 60.86% (in tryptose broth), and 41.40 to 62.50% (in glycerol dextrose broth), of Brucella abortus strains, 25.00 to 83.30 per cent (in tryptose broth) and 83.30 to 100.00 per cent (in glycerol dextrose broth) of Brucella melitensis strains showed increased growth over the control. 82.20 per cent of amniotic fluid samples from humans showed anti-brucella activity with lytic zones varying from 7-19 mm. Amniotic fluid from cows and sheep had no antibrucella activity.

Amniotic Fluid↗
PubMedDate not supplied

Induction of human vascular endothelial stress fibres by fluid shear stress.

Endothelial cells of the arterial vascular system and the heart contain straight actin filament bundles, of which there are few, if any, in the venous endothelium. Since stress fibre-containing endothelial cells within the vascular system tend to be located at sites exposed to particularly high shear stress of blood flow, we have investigated, in an experimental rheological system (Fig. 1), the response of the endothelial actin filament skeleton to controlled levels of fluid shear stress. Here we report that endothelial stress fibres can be induced by a 3-h exposure of confluent monolayer cultures of human vascular endothelium to a fluid shear stress of 2 dynes cm-2, approximately the stress occurring in human arteries in vivo. Fourfold lower levels of shear stress that normally occur only in veins, had no significant effect on the endothelial actin filament system. The formation of endothelial stress fibres in response to critical levels of fluid shear stress is probably a functionally important mechanism that protects the endothelium from hydrodynamic injury and detachment.

Actinin↗
PubMedDate not supplied

Effects of different mediators or cytokines and monoclonal antibodies to adhesion molecules on leukocyte adhesion in rat mesenteric venules.

Leukocyte adhesion (LA) to the endothelium of postcapillary venules is considered to be an important step in the inflammatory response. The recruitment of blood leukocytes into sites of inflammation involves a well-coordinated and dynamic sequence of events in which several cellular adhesion molecules (CAMs) and chemotactic cytokines play an active role. The aim of the present study was to elucidate receptor-mediated interaction in mesenteric venules of leukocyte rolling/adhesion and plasma leakage. We applied intravital microscopic techniques, with the help of an analogous video image processing system, to measure changes in the microvascular integrity. Rat monoclonal antibodies (MoAb) to different CAMs were administered before inflammatory stimuli were applied. Topical application of different doses of either lipo-polysaccharide (LPS), fMet-Leu-Phe, zymosan, complement C5a, Tnf-alpha, interleukin-1beta (IL-1beta), IL2 or IL-6 resulted in a dose-dependent increase in LA. The injection of a MoAb (1 mg/kg), 15 min prior to the LPS challenge, resulted in (1) total inhibition of LA, when MoAb to rat L-section, LFA1-beta and VLA-4 were used, (2) a moderate effect with LFA-1beta and Mac-1 MoAb, and (3) only a weak influence on LA by the MoAb to rat ICAM-1 (1 mg/kg). No effects were seen with IgG1 control MoAb. LA in acute models of inflammation can be regarded as a consequence of time-dependent differential effects of CAMs, as observed through the application of different MoAb.

Animals↗
PubMedDate not supplied

Platelet function in the dorsal skin fold chamber of the rat.

The majority of the preparations described for studying platelet functions in vivo require the administration of anesthetic agents and surgery. Some anesthetic which are frequently used in microvascular research (such as ketamine hydrochloride and pentobarbital) are reported to exert an effect on platelet properties themselves. Using a modified chamber preparation situated in the rat's dorsal skin fold, it is possible to study platelet function in the same rat with or without anesthesia. Thrombus formation is induced in arterioles and venules by argon-laser irradiation with a local capacity of 25mW and an exposure time of 1/30 s. Platelet function was studied for ten successive days in the same group of rats to examine the model's aptitude for long-term investigations. There was no significant alteration in platelet response during the experimental period. To evaluate the potential antithrombotic effects of the anesthetics, the animals were studied before and after the application of ketaminehydrochloride (130 mg/kg b.w., pentobarbital (25 mg/kg b.w.), or urethane (1,25 g/kg i.m.). The first two drugs caused significant increase in the number of laser injuries in arterioles and venules, although the effect of pentobarbital was weaker especially in venules. The influence of thrombus formation while using these anesthetics could influence the testing of antithrombotic drugs. Urethane had no effect on laser-induced thrombus formation. Furthermore, special attention was paid to spontaneous and laser-induced vasomotion with respect to thrombus formation.

Anesthetics↗