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Biomedical subjects

F Rossi

Publications and source records attributed to F Rossi.

At least 721 records · Page 40Linked to original sources
PubMed1980

Contact-activated factors: contaminants of immunoglobulins preparations with coagulant and vasoactive properties.

The intramuscular or intravenous administration of ISG prepared from human plasma by ethanol fractionation can elicit such reactions as pain at the injection site, flushing, and even hypotension. Similar adverse reactions to plasma protein fraction, a volume expander also made by ethanol fractionation, have been associated with PKA (Hageman factor fragments) in the product. Twenty-five lots of commercial ISG were therefore analyzed for PKA and kallikrein, components of the contact activation system which could mediate such reactions through the generation of kinins in recipients. Kallikrein activity ranged from undetectable levels to > 60% of the total potential kallikrein activity in normal plasma. PKA, which was measured by its ability to catalyze the conversion of prekallikrein to kallikrein, ranged from 5% to 3950% of the activity in a reference plasma protein fraction that had caused hypotension. All but five lots increased vascular permeability in the guinea pig. The five lots which caused no increased were also the lowest in PKA and kallikrein activity. When ISG ws subjected to gel chromatography to separate the enzymic contaminants from immunoglobulin G, only the fractions containing PKA and/or kallikrein increased vascular permeability. Several lots of ISG shortened the nonactivated partial thromboplastin time of normal plasma fro 236 sec to 38 to 55 sec. During gel chromatography, coagulation activity was eluted in a position corresponding to a molecular weight of 150,000; it was inhibited by antibody to human factor XI. These data indicate that factor XIa is responsible for the coagulant activity observed and that PKA and/or kallikrein are potential mediators of vasoactive reactions to ISG.

Animals↗
PubMed1980

Modulatory effect of brain acetylcholine on reflex-induced bradycardia and tachycardia in conscious rats.

The effects of intracerebroventricular (i.c.v.) injection of physostigmine and hemicholinium-3 (HC-3) on reflex bradycardia and tachycardia have been studied in unanesthetized rats. The reflex increases and decreases in heart rate were elicited by i.v. injection of norepinephrine and sodium nitroprusside, respectively. Physostigmine (5-10 micrograms) increased basal mean arterial pressure (MAP), reduced basal heart rate (HR), enhanced the reflex bradycardia and reduced reflex tachycardia. Physostigmine did not modify either the pressor effect of norepinephrine, the depressor effect of sodium nitroprusside or the responsiveness of peripheral muscarinic receptors. Pretreatment (i.c.v.) with atropine (0.3 micrograms) completely abolished the effect of physostigmine on MAP, HR, reflex bradycardia and reflex tachycardia. Pretreatment (i.c.v.) with mecamylamine (50 micrograms) did not modify the effect of the cholinesterase inhibitor on MAP, HR and reflex tachycardia, but inverted its effect on reflex bradycardia. Injection of HC-3 (20 micrograms i.c.v.) did not modify MAP, but reduced HR and inhibited both reflex bradycardia and reflex tachycardia. The HC-3 bradycardic effect started within minutes and lasted for about 1 hr, while the depressor effect on the reflexes began only after 15 min and continued for several hours. In addition, i.c.v. pretreatment with HC-3 completely abolished all the effects of physostigmine on MAP, HR, reflex bradycardia and reflex tachycardia. These results suggest that brain acetylcholine has a modulatory effect on baroreceptor reflexes. This modulation operates through muscarinic receptors in reflex tachycardia and through both muscarinic and nicotinic receptors in reflex bradycardia.

Acetylcholine↗
PubMed1980

Derivatives of 1,2,3,3-tetramethyl-2-azabicyclo[2.2.2]octan-5-trans-ol with antiarrhythmic and other activities. III.

A new series of aliphatic and aromatic esters of 1,2,3,3-tetramethyl-2-azabicyclo[2.2.2]octan-5-trans-ol is described. A number of these compounds showed antiarrhythmic activity in guinea pigs and mice, as well as surface anesthesia in rabbits and infiltration anesthesia in mice, superior or similar to that of lidocaine. The circulatory, cardiac and respiratory effects in dogs and hens are also described.

Anesthetics, Local↗
PubMed1980

Derivatives of 1,2,3,3-tetramethyl-2-azabicyclo[2.2.2]octan-5-trans-ol with antiarrhythmic and other activities. IV.

A new series of aliphatic and aromatic amides of 5-trans-(3-aminopropoxy)-1,2,3,3-tetramethyl-2-azabicyclo[2.2.2] octane is described. A number of these compounds showed antiarrhythmic activity in guinea pigs and mice, as well as surface anesthesia in rabbits and infiltration anesthesia in mice, superior or similar to that of lidocaine. The circulatory, cardiac and respiratory effects in dogs and hens are also described.

Anesthetics, Local↗
PubMed1979

Interrelationship between oxygen consumption, superoxide anion and hydrogen peroxide formation in phagocytosing guinea pig polymorphonuclear leucocytes.

The paper presents an experimental procedure for a simultaneous assay of oxygen consumption, O2- release and H2O2 accumulation at a very early stage of the respiratory burst that is induced by phagocytosis in guinea pig polymorphonuclear leucocytes. The main findings are as follows: (a) The oxygen consumption that is measurable does not correspond to all oxygen that is reduced. The relationship between the actual oxygen consumed and the amount that is reduced depends on the fate of the intermediate products O2- and H2O2. (b) O2- is measurable extracellularly by the reduction of cytochrome c. When cytochrome c oxidizes the extracellular O2-, molecular oxygen is formed. This fact is shown by a decrease of oxygen consumption. The molar ratio between the O2- detected and the oxygen given back is 1. (c) The amount of O2- released from the cells accounts for only a small part of oxygen actually reduced. (d) H2O2 is detectable only in the presence of NaN3. In this condition almost all oxygen consumed is recovered in the form of H2O2. The molar ratio O2/H2O2 is near unity. The amount of H2O2 derived from dismutation of O2- released is only an aliquot of the total H2O2 accumulated. Thus, most of H2O2 is derived from intracellular sources. (e) In the absence of inhibitors of H2O2 degrading reactions, no detectable accumulation of peroxide occurs. Under these conditions, the main part of H2O2 formed is degraded in almost equal amount by catalase and myeloperoxidase, while only a small aliquot is degraded by NaN3 insensitive reactions.

Animals↗