Biomedical subjects
Publications and source records attributed to R Weiss.
A high incidence of Klebsiella contamination in German 'Warmblut' and Thoroughbred stallions is reported. The organism was recovered from the nostrils, prepuce, pre-ejacultory secretion and, in some cases, on the body surface, in the faeces and on the ground of the covering (mating) yard. Fertility was not affected. However, differences of virulence were observed and Type 5 proved to be the most pathogenic.
INTRODUCTION: In part I of this paper (Schulz et al., 1975) it was shown that in the initial phase of experimental erysipelas a transition from the vascular processes to a systemic connective tissue reaction can be demonstrated in different species. It is the purpose of this paper to describe the chronic phase of the disease with special emphasis on polyarthritis. MATERIALS AND METHODS: 12 spontaneously diseased and 22 experimentally infected pigs were used in experiments to study the pathogenesis of the disease. In addition, 74 Wistar rats and 148 Sprague-Dawley rats were used in the experiments. All experimental animals were specific-pathogen-free and were parenterally infected with the standardized E. insidiosa serotype B strain T 28. The observation period for the pigs was up to 2 years, for the rats up to 11 months. The methods used for pathohistological and electron microscopical studies are described in part I. Immunihistological studies were carried out on synovial tissue with peroxidase-conjugates of goat-anti-pig-IgG, goat-anti-pig-IgM, pig-collagen, E. insidiosa-homogenate and heat-aggregated-pig-IgG. Furthermore, goat-anti-pig-IgG and rabbit-anti-pig-C3 conjugated with FITC were used. Passive hemagglutination tests and Latex agglutination test (Singer and Plotz) were performed to demonstrate rheumatoid factors and collagen antibodies. RESULTS: Polyarthritis occurred in pigs between the 4th and 10th day p.i. and between the 4th and 8th day p.i. in nearly 100% of the infected rats. Fibrinous exudation, proliferation and destruction with pannus formation are marked in most of the joints examined during the first three months. Fibrosis begins 30 days p.i. in the rats' joints and is most severe in both species between the 5th and 8th month. 3 types of lining cells may be differentiated electron microscopically: A (M) cells, B (F) cells and an intermediate form which is found in both species most frequently. Swelling of the endothelial cells together with constriction of the lumen and thickening of the basal membrane occurs in the capillaries. DISCUSSION: A comparison of chronic erysipelas polyarthritis in pigs and rats with rheumatoid arthritis of men reveals many morphological and immunological similarities between the two diseases. Systemic connective tissue activation manifests itself in organs predilected for rheumatic changes, such as heart valves, endocardium and joints. The possible prepetuation of the processes by specific or nonspecific immunomechanisms or by deposits of fibrin is discussed. In addition, experimental erysipelas is reproducible in nearly 100% of the animals given one single subcutaneous application of one defined bacteria strain. Therefore too, erysipelas is suited as an animal model for human rheumatic diseases.
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Cat papillary muscles were depolarized from about -80 mV to -50 mV by addition of KCl to Tyrode's solution. This causes an inactivation of the Na-carrying system so that the remaining transmembrane inward current is due, in practice, to Ca. Such action potentials show a reduced rate of rise, a greater overshoot, and a shorter duration. These parameters vary somewhat with the strength of stimulation and, particularly, with frequency. Excitability as well as contractility of the K-depolarized fibers are completely abolished by Ca withdrawal or by addition of verapamil or D 600, which block the transmembrane Ca inward current specifically. Conversely, extra Ca or epinephrine overcomes the verapamil and C 600 effects by increasing the transmembrane Ca influx. As soon as the papillary muscles are returned to Tyrode's solution with normal K0 the Na-carrying system is reactivated. Then Ca withdrawal or Ca-antagonistic compounds lose their inhibitory influence on excitation, whereas excitation-contraction uncoupling persists.
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CD studies of the deoxyoligomer series d(pT)(n) and d(pA)(n) show increasing CD maxima for oligo (dT)'s with chain length variation from two to seven, while oligo (dA)'s exhibit a decreasing CD maximum. Concentrated solutions of NaClO(4) cause a decrease in the CD of longer oligo (dT)'s towards the CD of d(pT)(2) which is different from oligo dA's. Probably base-sugar interactions are important in the observed conformational effects. The chemically synthesized oligomers dpApApTpT and dpTpApTpA show deviations in their CD spectra which reflect a dominating conformational effect of d(pA)(2) in the former but not in the alternating isomer.
Sickle cell anemia (SS) is associated with abnormalities of the red cell membrane and decreased red cell deformability. The present study assesses globin chain binding to stroma in SS, sickle cell trait (AS), and nonsickling (AA) cells. The results indicate that there is preferential binding of newly synthesized beta(S) globin to red cell stroma in SS cells and preferential binding of beta(S) to stroma compared to beta(A) in AS cells. These studies show that beta(S) globin binding to stroma accompanies the membrane abnormalities in SS and AS patients.
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