Physiologie (Bucarest)最新文献

We studied the histochemical behaviour of neutral non-lysosomal and acid lysosomal proteases of the myocardium in heart anoxia by aorta-clamping, using an experimental model alike to the open heart surgery conditions. After one hour of blood deprivation we found destabilization, conglomeration, diffusion and extracellular release of the histochemical reactions for neutral BANA-reactive proteases, cathepsin B, acid and neutral gelatinases in monkey, rat and mice myocardium, in connection with lytic ultrastructural lesions. Intracardiac perfusion with cardioplegic solution exerted a partial protective effect which is improved by adding Trasylol, a protease inhibitor. Administration of Trasylol by intravenous injections preceding aorta clamping, or/and by intracardiac perfusion after aorta clamping, normalized the histochemical reactions of proteases together with the ultrastructural organization of the myocardial fibres. Acting especially by the inhibition of membrane serine proteinases, Trasylol may intercept membrane permeabilization events, impairing the proteolytic cascades triggered by anoxia.

In rats recovered after 13 days of cosmic flight a diminution of acid and neutral glycoproteins was observed in the gastric mucosa and proximal segments of the small intestine: the decrease was less evident in the sublingual glands and colon. Leucine aminopeptidase and acid phosphatase in the small intestine were intensified. No significant changes were observed in the other enzymes investigated. Acid phosphatase showed a more intense activity in the endocrine pancreas B cells. The alterations observed after 13 days of flight in the "Cosmos 1887" biosatellite are significant but less marked than after 18 days of flight, and more accentuated than after 5-7 days of flight.

Propranolol induces basal achlorhydria in 30.7% of the patients, decreases significantly the HCl secretion in 42.3%, does not change it in 25% and increases it in 1.9%. After histamine stimulation (Kay test) propranolol decreases HCl in 57% and increases it in 43% of the cases. Propranolol induces a significant decrease of carbon anhydrase in the gastric mucosa. Serum gastrin is not significantly decreased after propranolol treatment. Isoprenaline increases the HCl secretion in all the patients investigated. Propranolol suppresses the effect of isoprenaline in 28.6% of the cases, decreases it in 33%, does not change it in 19% and increases it in 19%. The action of isoprenaline is not influenced by atropine, so the mechanism of action of the beta agonist is non-cholinergic. The gastric juice volume is not changed significantly by the blockage or stimulation of beta receptors. The beta adrenergic nervous system stimulates HCl secretion.

Components of the autonomic control of the heart were studied in 5 young normals subjected to: 1) sustained lung inflation (SLI) in various postures; (2) mental loading by concentration of attention, 3) face immersion in cold water under SLI or snorkel breathing, when sitting; 4) superposition of above experimental interventions. We recorded cardiotachogram (RR interval) and T-amplitude from ECG, ear lobe photoplethysmogram, digital impedance rheogram, thermistor respiration. Cardiac data were explored by means of Fourier spectral analysis on a M 118 B microcomputer. Results caution that allegedly unilateral stimulation by some "vagal" maneuvers triggers in fact amphotropic heart rate control menus involving sympathetic nonreciprocal response. Subsequent bradycardia should be interpreted as an absolute indicator of the parasympathetic function only when a separate measure of the sympathetic counterpart is available. In vigil young adult at physical rest the medullary cardiovascular centers appear as subjected to "sliding capture" by their prominent input signal--as determined by various receptor stimulation or cortical status, the latter preserving a higher priority at competing task demands. In a coupled study 9 normals were polygraphically monitored (EEG, EOG, ear duct temperature and the above variables as well) during 2 nonconsecutive nights and cardiac data were spectrally examined along various sleep stages. Results suggest an increased dual autonomic tone during REM that could be related to reported stage-specific arrhythmias. Reciprocal dynamics of the respiratory versus lower frequency variability of RR interval from NREM to REM sleep points to a useful discriminant for computer sleep stage scoring.

The paper reviews basic concepts, measurement principles, abnormality criteria, errors and limitations as well as technical aspects involved in the intracavitary exploration of sinus node dysfunction in man, from a standpoint connecting the cardiologist's and the clinical engineer's views.