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Biomedical subjects

M Buraglio

Publications and source records attributed to M Buraglio.

6 recordsLinked to original sources
PubMed1987

Congenital deficiency of alpha-2-adrenoceptors on human platelets: description of two cases.

The biochemistry and functionality of platelets from two related subjects (mother and son) with alpha-2-adrenoceptor-deficient platelets has been evaluated. Radioligand binding experiments with the specific alpha-2-adrenergic-receptor antagonist, 3H-yohimbine, showed a drastic reduction of alpha-2-adrenoceptors in platelets from both subjects in comparison with the control values. Electron microscopy studies revealed a normal morphology and a normal number of alpha granules and dense bodies. Levels of adenine nucleotides; 5-hydroxytryptamine; B-thromboglobulin; platelet-factor-4 and thromboxane A2 production were within normal limits. Platelet aggregation and 5-hydroxytryptamine production in response to adrenalin (at concentrations up to 50 microM) were absent, whereas ADP, AA, PAF, collagen and thrombin-induced aggregation, secretion, Ca++ flux and thromboxane A2 production were normal. The inhibitory effect caused by different concentrations of prostacyclin on Ca++ flux, aggregation, secretion and thromboxane A2 production of platelet functionally lacking of alpha-2-adrenoceptor was not distinguishable from control platelets and platelets preincubated with yohimbine.

Adult↗
PubMed1987

Absence of (-) [3H]desmethoxyverapamil binding sites on human platelets and lack of evidence for voltage-dependent calcium channels.

The two major pathways for Ca2+ entry into cells are potential-sensitive channels and receptor-operated channels. The main object of this investigation was to identify which mechanism regulates Ca2+ entry into human platelets. Platelet stimulation with thrombin, adenosine diphosphate, platelet activating factor and arachidonic acid resulted in a concentration-dependent 2.5-3-fold increase in cytoplasmic free calcium concentration over the basal levels (140 +/- 32 nM or 104 +/- 21 respectively) as measured with the fluorescent dyes Quin-2 and Fura-2. Adrenaline and collagen had no effect in promoting intracellular Ca2+ increase as measured with Quin-2 and little effect when measured with Fura-2. Incubation of Quin-2-loaded platelets with the calcium antagonists verapamil and diltiazem, which are known to inhibit Ca2+ entry from voltage-gated channels in many types of cells, over the concentration range 10(-8) - 10(-4) M did not alter significantly either the resting or the cytoplasmic free Ca2+ after stimulation of platelets by several agonists. Moreover, the calcium antagonists exhibited little or no effect on aggregation and 5-hydroxytryptamine secretion induced by platelet activating factor, adenosine diphosphate, collagen or arachidonic acid in whole blood, platelet-rich plasma or washed platelets when employed at concentration ranges as above. Similar results were obtained in washed thrombin-stimulated platelets. High doses of verapamil (but not diltiazem) inhibited platelet aggregation and secretion in response to adrenaline. Direct radioligand binding studies with (-)[3H]desmethoxyverapamil showed that platelet membranes have no receptors for this drug, suggesting that Ca2+ entry occurs in human platelets via a pathway different from potential-sensitive Ca2+ channels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Antitubercular agents].

Author resume the most important stages of the antitubercular struggle. Then they consider the action mechanisms of single drugs, often not well known, such the action mechanism of pyrazinamide. At present, the criteria of effectiveness, tolerance, availability and economy allow to use rationally and not arbitrarily the antitubercular drugs and these criteria also assure the best therapeutic results.

Antimetabolites↗
PubMed1984

Changes of lymphocyte beta-adrenergic receptors after surgical stress.

In this study the authors' purpose was to observe the effects of surgical stress on the number of lymphocyte beta-adrenergic receptors in hypertensive and normotensive subjects. It was noticed that after surgery a significant reduction occurred in the number of binding sites of lymphocytes of both hypertensive and normotensive subjects. The time course of recovery to the pre-operative values of binding sites varied between the two groups, being slower in normotensive than in hypertensive patients. This might suggest a different pattern of regulation of the beta-adrenergic receptor between hypertensive and normotensive subjects.

Adult↗