Biomedical subjects

E Giannella

Publications and source records attributed to E Giannella.

21 records · Page 2Linked to original sources

PubMed1987

The antianaphylactic action of histamine H2-receptor agonists in the guinea-pig isolated heart.

The effects of histamine and of H1- and H2-receptor agonists on the response to specific antigen were studied in isolated hearts taken from actively sensitized guinea-pigs. Histamine and H2-receptor agonists (dimaprit, impromidine) dose-dependently decrease the positive chronotropic and inotropic effects, and the severity of arrhythmias evoked by the challenge of sensitized hearts with specific antigen. Nordimaprit and the selective H1-receptor agonist 2-pyridyl-ethyl-amine (2-PEA) did not modify the patterns of cardiac anaphylaxis. The positive inotropic and chronotropic responses of the isolated heart to exogenous histamine appear to be partly reduced in the presence of dimaprit. The H2-receptor agonists decrease the amount of histamine released during cardiac anaphylaxis which is increased by cimetidine, while nordimaprit and PEA were ineffective, indicating an inhibitory function afforded by H2-receptors in cardiac anaphylaxis.

Anaphylaxis↗

PubMed1987

Mast cell histamine release induced by intermediate products of arachidonic acid metabolism.

This study was performed to evaluate the role of intermediate products of arachidonic acid metabolism on histamine release from rat serosal mast cells. Arachidonic acid in concentrations ranging from 10(-9) to 10(-4) M caused no histamine release from purified rat peritoneal mast cells. High concentrations (10(-6)-10(-6) M) of the terminal products of the arachidonic acid metabolism were also devoid of any significant histamine-releasing properties. The metabolic activation of arachidonic acid with prostaglandin-H-(PGH)-synthase isolated from calf seminal vesicles, evoked a significant release of histamine from rat serosal mast cells. The liberation of histamine was not accompanied by a significant leakage of lactic dehydrogenase (LDH) and the electron microscopical features were consistent with an exocytotic release. The phenomenon was blocked by reduced glutathione (GSSH) and by D-mannitol, a hydroxyl free-radical scavenger. These results suggest that free radical derivatives of arachidonic acid are generated during the catalysis which triggers mast cell histamine release.

Animals↗

PubMed1986

Stimulation and resection of Vidian nerve in patients with chronic hypertrophic non-allergic rhinitis: effect on histamine content in nasal mucosa.

Parasympathetic innervation of nasal mucosa plays an important role in the pathogenesis of chronic hypertrophic non-allergic rhinitis (C.H.N.A.R.). The present study investigated the effect of Vidian nerve stimulation and resection on the histamine contents and on the morphological pattern in mucosal samples of patients with C.H.N.A.R. Vidian nerve stimulation determines a significant decrease in histamine content in the samples examined; microscopical observations showed significant variations in the glandular, stromal and vascular components. The changes indicate an enhanced secretory activity, intensive vasodilatation and active degranulation of mast cells, which were significantly decreased in number in the samples obtained after 90 sec of stimulation. The neurectomy of the Vidian nerve resolves quite completely the clinical symptomatology and in parallel decreases the mucosal histamine contents, which are increased in patients with C.H.N.A.R. before the operation in comparison with the normal controls.

Chronic Disease↗