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At least 1,153 records · Page 64Linked to original sources
PubMed2004

Tolerance-induced receptor selection: scope, sensitivity, locus specificity, and relationship to lymphocyte-positive selection.

Receptor editing is a mode of immunological tolerance of B lymphocytes that involves antigen-induced B-cell receptor signaling and consequent secondary immunoglobulin light chain gene recombination. This ongoing rearrangement often changes B-cell specificity for antigen, rendering the cell non-autoreactive and sparing it from deletion. We currently believe that tolerance-induced editing is limited to early stages in B-cell development and that it is a major mechanism of tolerance, with a low-affinity threshold and the potential to take place in virtually every developing B cell. The present review highlights the contributions from our laboratory over several years to elucidate these features.

Animals↗
PubMed1982

Relevance of selectivity and non-selectivity in beta-adrenoceptor blocking drugs.

1 The heart rate responses to increasing doses of isoprenaline (n = 6) (during infusion with atropine 0.5 mg/min i.v.) and noradrenaline (n = 5), (during infusion with phentolamine 160 mg/h i.v.) were recorded before and after the intravenous administration of propranolol (15 mg) or metoprolol (15 mg). 2 In the doses used, metoprolol was less potent than propranolol in antagonizing isoprenaline-induced tachycardia, during atropine infusion. 3 In volunteers treated with phentolamine both metoprolol and propranolol produced similar inhibition of noradrenaline-induced tachycardia, indicating comparable beta 1-adrenoceptor blockade in the doses used. 4 The fact that the shift of the dose-response curve of isoprenaline-induced tachycardia was smaller after metoprolol than after propranolol supports the hypothesis that beta 2-adrenoceptors are present in the heart.

Adrenergic beta-Antagonists↗
PubMed1990

The influence of selected tannin-containing plant species on the tenacity of pathogenic bacteria in an in-vitro rumen system. 1. Communication: the influence of selected plant species on the tenacity of Cl. perfringens.

The effect of plant species containing tannins on the tenacity of Cl. perfringens was elucidated. Trials were purchased in physiological saline solution and in a rumen-fluid-medium under anaerobic conditions. The results obtained show, that within minutes the tenacity of Cl. perfringens can be reduced by some of the tested plant material not only in physiological saline solution but also in a rumen-fluid-medium. The results indicate that the reaction of some vegetable tannins and Clostridium perfringens germs is a specific one and could be used in controlling diseases caused by Clostridium perfringens.

Acacia↗
PubMed1984

Method of selective and non-selective angiocardiography for the horse.

A practical and safe method of angiocardiography for the horse is described. The technique involved the rapid injection of 50 to 150 ml contrast agent via catheters in the right and left heart, pulmonary artery and aorta. The examination was carried out with the horse in the standing position or under general anaesthesia. Angiocardiograms were performed on 10 normal horses and satisfactory pictures of the right and left ventricles, pulmonary arteries, aorta and coronary circulation were obtained. The technique was also used in a foal with severe congenital heart disease. The most practical methods of recording the images in the standing position were cinefilm or video taperecording. In the recumbent position both cinefilm and radiographs were taken. No damage to the heart was inflicted by the catheters and only a few ventricular premature contractions (less than five) were produced by the pressure of injection. No signs of toxicity were recorded using repeated injections of contrast material (ie, less than 600 ml).

Anesthesia, General↗
PubMed1979

Selective adaptation to frequency-modulated tones: evidence for an information-processing channel selectively sensitive to frequency changes.

Exposure to an FM tone elevates FM threshold but not AM threshold. This holds for a wide range of frequency deviations (delta F = +/- 0.4 Hz- +/- 30 Hz at least) provided that modulation frequency is low (fm = 2 Hz), but if fm is somewhat higher (e.g., 8 Hz) the finding only holds for small frequency deviations. FM threshold can rise with time up to an adapting duration of at least 1200 s, through this buildup depends on frequency deviation. Exposure to an AM tone elevates AM threshold, but not FM threshold, over a wide range of modulation depths (at least m = 5%--50%). Quasi-FM (QFM) adapting tones resemble FM adapting tones in their effects upon FM and AM sensitivities, even though QFM and AM adapting tones have identical power spectra. Exposure to a pure tone produces no difference between FM and AM threshold elevations. These data can be explained if the human auditory pathway contains separate information-processing channels for AM and FM signals whose sensitivities do not overlap even with suprathreshold stimuli. We suppose that the FM channel (but not the AM channel) is sensitive to changing differences (or ratios) between signals from different sites along the basilar membrane.

Adaptation, Psychological↗