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Biomedical subjects

A Tirelli

Publications and source records attributed to A Tirelli.

At least 37 records · Page 2Linked to original sources
PubMed1992

Glutathione (GSH) improved haemostatic and haemorheological parameters in atherosclerotic subjects.

Blood samples from ten patients with clinically evident manifestations of atherosclerotic disease were used to evaluate in vitro the effects of exogenous glutathione (GSH) on platelet aggregation and on blood filtration and viscosity. In two groups, each of ten atherosclerotic patients, matched for sex, age, prevalent localization, duration and gravity of disease, the effects of GSH infusion (600 mg every day for seven days) on the haemocoagulative pattern, platelet aggregation and blood filtration and viscosity were evaluated in a double-blind, placebo cross-over trial. The GSH in vitro addition resulted in a significant increase in blood filtration and a significant decrease in blood viscosity and platelet aggregation. The venous GSH infusion both significantly decreased blood viscosity and increased blood filtration. Partial thromboplastin time was lengthened after GSH infusion even thought it remained in the normal range.

Aged↗
PubMed1985

[Accentuated and irregular post-maximal deflection in thromboelastographic tracings: occurrence in various pathologies].

The increased and irregular post-maximal deflection of the two limbs of thromboelastographic traces has been variably interpreted by the Authors who utilize TEG as a global screening test for haemostasis evaluation. These thromboelastographic patterns have been attributed either to enhanced fibrinolytic activity or to raised clot's rectractility or even to incorrect technique. In our study, 1701 TEG's traces carried out in the last five years have been reviewed in order to evaluate the incidence of such patterns in both healthy subjects and in patients affected by different diseases. The data obtained show that such irregular post-maximal deflection's patterns are quite absence in healthy subjects while reaches a statistically significant incidence only in patients affected by diabetes mellitus, obesity or systemic hypertension. The results seem to suggest that the increased and irregular post-maximal TEG deflection is not a simply product of technique's mistake but may represent an useful index of some haemostatic alterations which need further studies.

Adult↗
PubMed1984

[Effects of low O2 tension on platelet aggregation].

Several studies in animals suggest a link between haemocoagulative patterns and blood gas changes. Furthermore platelet functions seem to be affected by O2 concentrations. In the present study we have evaluated "in vitro" the effect of low PO2 concentrations on platelet aggregation in man. In 15 normal subjects (mean age 32 +/- 5) platelet aggregation ADP (end conc. 1,25 microM) and collagen induced 2 micrograms/Ml) was determined before and after exposition to low PO2 concentrations (O2 conc. 5,04%). The results show that low PO2 concentrations determine a significant increase (P less than 0,001) of platelet aggregation as compared to controls. Although the mechanism of the direct influence of PO2 concentrations upon human platelet is unclear, this finding suggest new therapeutic approaches in chronic lung obstructive diseases.

Adenosine Diphosphate↗
PubMed1984

P50 values determined by tonometry and by simplified techniques.

Actual determination of the position of the oxygen hemoglobin dissociation curve (P50) was compared to three methods of estimating P50 in 39 patients with various diseases. There was a significant correlation between determined and estimated P50 values (P less than 0,001) for each of the methods studied. The data suggest that calculating P50 is reliable and may replace the need for actual measurement.

Adult↗
PubMed1984

Depressed antithrombin III biological activity in opiate addicts.

Antithrombin III activity was significantly decreased in opiate addicts, but no difference was found between addict and control groups in antithrombin III plasma concentration. Moreover, glycosylated haemoglobin concentration was increased in opiate addicts, but no correlation between glycosylated haemoglobin and antithrombin III activity was found. These data show that in opiate addicts there is depressed biological activity of antithrombin III. Further characterisation of the molecular changes in antithrombin III in addicts is needed to establish whether the impaired activity is affected by altered glucose metabolism.

Adolescent↗
PubMed1984

Rapid decrease of platelet aggregation (ADP--and collagen--induced) and of platelet circulating aggregates by the artificial pancreas in insulin-dependent diabetics.

The aim of the present study was to evaluate the role of the strict metabolic control achieved with the aid of an artificial pancreas (Biostator, Miles) on platelet functions in insulin-dependent diabetics (n = 20). Platelet aggregation responses to both ADP and collagen, as well as circulating platelet aggregates according to Wu and Hoak, were determined before and after 24 hours of complete metabolic control; as control group, 18 insulin-dependent diabetics were only monitored without attempts to normalize their blood glucose behaviour. A significant decrease in ADP induced aggregation (p less than 0.01) and circulating platelet aggregates (p less than 0.001) was observed in diabetics during the period of strict metabolic control. No changes were observed in the control group. The present data suggest that the increased platelet activity in diabetes is a consequence of the metabolic derangement of the disease.

Adenosine Diphosphate↗
PubMed1983

[Changes in mean erythrocyte volume and 2,3-diphosphoglycerate in two groups of diabetic subjects].

Mean corpuscular volume and Red Blood Cell 2-3, diphosphoglycerate in insulin dependent diabetics and in non insulin dependent diabetics were evaluated. Only in insulin dependent diabetics an increased mean corpuscular volume was found while in non insulin dependent diabetics red blood cell 2-3, DPG level appears to be reduced. These findings were not correlated with the metabolic parameters neither they seemed to be dependent upon sex, age or vascular disease. The Authors suggest that the increase of mean corpuscular volume might be indicative of a tendency to macromegaloblastosis in insulin dependent diabetics; with regard to RBC 2-3, DPG level it seems to be extremely variable in dependence on oxygen request at the tissue level.

2,3-Diphosphoglycerate↗
PubMed1983

[Effect of pentoxifylline on the dissociation curve of oxyhemoglobin].

In 9 subjects with peripheral vascular insufficiencies the AA. have studied the behaviour of the oxyhaemoglobin dissociation curve before and after pentoxyphilline infusion. After this drug no variations were observed as it regards MCHC, 2-3-DPG and so on; however a positive correlation was found between 2-3-DPG and the Hill number. These results suggest that 2-3-DPG may influence the Hill number (which is the expression of the gradient of the oxyhaemoglobin dissociation curve) and therefore may interfere with O2 transport.

Aged↗
PubMed1982

Glucagon secretion in patients with hypoparathyroidism: effect of serum calcium on glucagon release.

The aim of the present study was to evaluate the influence of changes in the serum calcium concentration upon glucagon secretion in man. For this purpose, a group of subjects with either idiopathic (four cases) or secondary (two cases) hypoparathyroidism was submitted to an arginine test (0.5 g/kg) before and after the correction of hypocalcemia. In the presence of hypocalcemia, the glucagon response to the amino acid was modest and delayed (glucagon peak, 150 +/- 28 pg/ml). The acute correction of hypocalcemia produced a striking increase in basal glucagon levels (125 +/- 24 vs. 75 +/- 15 pg/ml; P less than 0.01) and restored the glucagon peak in response to arginine (270 +/- 50 pg/ml; P less than 0.01). The increase in plasma glucose triggered by arginine was augmented under normocalcemic conditions, while the pattern of plasma insulin response was quite similar. These results indicate that glucagon secretion in man is critically dependent on the serum calcium concentration.

Adult↗
PubMed1981

Further studies on the significance of circulating platelet aggregates induced by somatostatin in man.

The aim of the present study was to further evaluate the significance of circulating platelet aggregates induced by somatostatin in insulin-dependent diabetic subjects. Eight insulin-dependent diabetics and eight normals were infused with somatostatin at increasing doses (250, 500, and 750 microgram/h), each dose for 30 min. In diabetics, somatostatin induced the appearance in blood of platelet aggregates in a dose-dependent fashion, the highest level being observed with the highest dose (750 microgram/h), p less than 0.005). In normals, circulating platelet aggregates were detected only with the infusion of the highest rate of somatostatin (p less than 0.025). This effect of somatostatin was reversible, since it tended to disappear 30 min after the infusion was stopped. In six additional insulin-dependent diabetics, a previous infusion of phentolamine (0.5 mg/min) completely prevented the appearance of platelet aggregates by somatostatin. No significant variation of the aggregation response to both ADP and collagen and the platelet count was seen in both experiments. Somatostatin, as expected, reduced the basal concentration of plasma glucose, glucagon, and C-peptide in both diabetics and normals. On the basis of these results, we suggest that somatostatin has some proaggregating capacity in vivo, probably by interacting with adrenergic mechanisms.

Adolescent↗
PubMed1980

[Thromboelastographic patterns in patients suffering from chronic obstructive lung disease after hyperventilation].

In an our previous study we studied the influence of O2 therapy administration on the thromboelastographic pattern of patients suffering from chronic obstructive lung disease. We showed that basal hypocoagulability of our patients became normal after O2 administration. In this study we refer the thromboelastographic pattern observed in patients suffering from the same disease before and after hyperventilation. We don't find any changes about total coagulability either in patients or in healthy subjects after hyperventilation. Therefore we suggest that the absence of any changes is due to PCO2 and pH variations that occur at the same time of PO2 modification during hyperventilation; PCO2 and pH variations may influence the haemoglobin oxygen affinity and annul the effect of the increase PO2 on the tissue oxygenation. We suppose that the increase of patients suffering from chronic obstructive lung disease, is due to decreased fibrinolysis or to increased production of prostacycline induced by hyperventilation.

Adult↗
PubMed1980

[Effect of circulating insulin on liver damage by CCl4 in the rat. I. Biochemical studies].

The authors have studied the damaging effects of CCl4 (0.05ml/Kg) in healthy rats, in alloxan-diabetic rats, and in rats treated with tolbutamide per os (100mg/Kg) for twenty days. Biochemical studies in these animals demonstrated that actually hyperinsulinemia has a preventive effect in relation to the damage produced by CCl4 as demonstrated by a decrease in bilirubinemia and transaminasemia.

Animals↗
PubMed1980

Circulating platelet aggregates induced by somatostatin in insulin-dependent diabetic subjects.

The present study was undertaken to reevaluate the influence of somatostatin on platelet function in insulin-dependent diabetics and in normal subjects. In in vivo studies, nine insulin-requiring diabetics were infused with cyclic somatostatin (250 microgram/hour) for 120 minutes or with saline, in randomized order. This dose of somatostatin, sufficient to depress the basal concentrations of plasma glucose, glucagon and C-peptide, resulted in no significant change of platelet aggregation response to either ADP or collagen. By contrast, a progressive and significant reduction of platelet aggregation response to ADP was found during saline infusion. A similar pattern of response was seen in normal subjects. In all diabetics, but not in normals, somatostatin induced the appearance of circulating platelet aggregates. In in vitro studies, somatostatin augmented the aggregation response to epinephrine in both normals and diabetics. In conclusion, somatostatin counteracts the decrease of platelet aggregation response to ADP seen in saline studies, induces the appearance of platelet aggregates in diabetics and potentiates the aggregation response to epinephrine (in vitro) in both normals and diabetics. These actions of somatostatin suggest some aggregating capacity of the peptide in man.

Adolescent↗
PubMed1979

[Acetylsalicylic acid and hormonal response in insulin induced hypoglycemia].

The influence of a short-term treatment with acetylsalicylic acid (ASA 3,2 g/daily), an inhibitor of endogenous prostaglandin synthesis, on plasma glucose, glucagon and growth hormone responses to insulin-induced hypoglycemia, has been investigated in seven subjects. ASA caused a slight but significant reduction in basal glucose levels, but did not alter the pattern of glucagon and growth hormone secretion following hypoglycemia. On the basis of these results, it is hypothesized that endogenous prostaglandins are not implicated in the response of pancreatic alfa-cell to hypoglycemia.

Adult↗