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Biomedical subjects

F Rossi

Publications and source records attributed to F Rossi.

At least 757 records · Page 42Linked to original sources
PubMed1976

Studies on the mechanism of metabolic stimulation in polymorphonuclear leukocytes during phagocytosis. Activators and inhibitors of the granule bound NADPH oxidase.

The effects of several known inhibitors and activators of peroxidase-catalyzed reactions have been studied on the NADPH oxidase activity of granules isolated from polymorphonuclear leukocytes at rest or during phagocytosis. Redogenic substances, such as ascorbate or hydroquinone, and superoxide dismutase, which are known to inhibit peroxidase-catalyzed reactions, also inhibited the NADPH oxidase activity of granules. Oxidogenic substances, such as guaiacol or resorcinol, and manganese, which are known to stimulate peroxidase-catalyzed reactions, also activated the NADPH oxidase activity of granules. Cyanide, an inhibitor of peroxidase-catalyzed reactions, inhibited the NADPH oxidase activity of granules isolated from resting leukocytes but only slightly affected that of granules isolated from phagocytosing cells, as previously reported. A list of the properties of the NADPH oxidase activity of granules and of peroxidase oxidase activity is given. The arguments in favor of and those against a possible identity of the two activities are discussed.

Animals↗
PubMed1976

Metabolic perturbation of the inflammatory cells.

An activation of the oxidative metabolism of phagocytes is a regular concomitant of phagocytosis as well as of other functions of these cells such as exocytosis, chemotactic locomotion, and immune-adherence. Several other substances, some of which may be found in the inflammatory site, are also able to stimulate the oxidative metabolism of phagocytes, for example phospholipases, antileucocyte antibodies, endotoxins, fatty acids, surfactants and fragments of complement. This paper deals with, (1) the molecular events occurring within the plasma membrane that trigger the stimulation of the oxidative metabolism. An experimental model is presented that involves redistribution of ions across the plasma membrane of leucocytes as the trigger of the stimulated respiration and exocytosis; (2) the intracellular localization of the enzymatic system that is the effector of the metabolic response. A scheme is proposed for the mechanism of this enzymatic system which accounts for the production of highly reactive compounds such as hydrogen peroxide, superoxide anion radical and hydroxyl radical during the metabolic activation of phagocytes.

Animals↗
PubMed1975

[Experimental analysis of some cardiovascular effects of Verapamil].

In vivo and in vitro experiments showed that Verapamil dilates the coronaries, prevents coronary spasm, produces Ca++-antagonism, offers protection against myocardial necrosis, prevents arrhythmia, reduces pressure, increases the purinergic reactivity and produces inhibition of platelet aggregation. It was devoid of competitive-adrenolytic activity in the heart and vessels. A methoxy derivative of the drug (D-600) had a negative inotropic and chronotropic action and was more hypotensive than Verapamil.

Amiodarone↗
PubMed1975

Studies on the mechanism of metabolic stimulation in polymorphonuclear leucocytes during phagocytosis. I. Evidence for superoxide anion involvement in the oxidation of NADPH2.

1. The oxidation of NADPH2 by leucocyte granules, as measured at acid pH in the presence of Mn-2+, was found to be inhibited by superoxide dismutase. 2. Omission of Mn-2+ markedly lowered the oxidase activity at acid pH, which was still inhibited by superoxide dismutase. 3. At alkaline pH the oxidase activity was lower than at acid pH. 4. During oxidation of NADPH2 by leucocyte granules, reduction of cytochrome c occurred which was partially inhibited by superoxide dismutase. 5. It was concluded that NADPH2 oxidation occurs through an enzymatic reaction and a nonenzymatic chain reaction. Superoxide anion (O-minus-2 and NADPH- free radical would be involved in the chain reaction. The differential sensitivity of NADPH2 oxidation to superoxide dismutase in different experimental conditions (see above 1, 2 and 3) was explained on the basis of changes in the properties of the chain reaction.

Animals↗