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Biomedical subjects

U Armani

Publications and source records attributed to U Armani.

At least 19 recordsLinked to original sources
PubMed2001

Maximal endothelial tissue plasminogen activator release is not impaired in patients with acute coronary syndromes before heparin treatment.

Procoagulant and fibrinolytic disturbances are described in patients with acute coronary syndromes (ACS), but whether defective maximal tissue plasminogen activator (t-PA) release from the endothelium is also present is still controversial. Previous studies did not take into consideration the contribution of heparin, which strongly affects fibrinolysis. Accordingly, in this study, we measured maximal t-PA release in patients with ACS before, during, and after heparin treatment. Maximal t-PA release was measured by the venous occlusion test in 38 hospitalized patients with confirmed ACS (18 acute myocardial infarctions and 20 unstable anginas) before starting heparin, during heparin treatment, and 4 and 12 h after discontinuation. Plasma plasminogen activator inhibitor type 1 (PAI-1), D-dimer and prothrombin fragment F1 + 2 were also measured. Eighteen age-matched subjects with no evidence of coronary disease were used as controls. At admission, patients showed significantly higher plasma levels of t-PA, PAI-1, and F1 + 2 than controls. Before heparin, maximal t-PA release was similar in patients and controls. Heparin treatment was associated with a significant increase of plasma t-PA, while it did not affect maximal t-PA release. Coagulative and fibrinolytic disturbances are present in patients with ACS, but these do not include maximal t-PA release. Among our patients, maximal t-PA release appears stable over time and is not affected by heparin treatment.

Aged↗
PubMed2000

4-Dialkylamino-1-(5-substituted or unsubstituted 1-phenyl-1H-pyrazol-4-yl)butan-1-ols: synthesis and evaluation of analgesic, anti-inflammatory and platelet anti-aggregating activities.

A number of 4-dialkylamino-1-(5-substituted or unsubstituted 1-phenyl-1H-pyrazol-4-yl)butan-1-ols 2a-n were synthesized and tested in vivo for anti-inflammatory and analgesic activities and in vitro for platelet anti-aggregating activity. Dimethylaminoderivatives 2b, e, g showed good analgesic activity; almost all of them had strong platelet anti-aggregating properties at a final concentration of 1 x 10(-3) M; pyrazoles 2c, d, f-h showed weak anti-inflammatory activity.

Analgesics↗
PubMed1998

Determination of plasma and serum homocysteine by high-performance liquid chromatography with fluorescence detection.

Determination of homocysteine in plasma or serum is becoming an important diagnostic procedure. Accurate, rapid and low cost methods for measuring homocysteine are therefore required. We have improved an HPLC method and made it suitable for clinical application. The total homocysteine in plasma consists of free homocysteine (i.e., reduced plus oxidized homocysteine in the non-protein fraction of plasma) and protein-bound homocysteine. The method consists of the following steps: reduction of the sample with tri-n-butylphosphine, precipitation of proteins with trichloroacetic acid (10%) and derivatization with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate. The derivatives are separated by reversed-phase high-performance liquid chromatography followed by fluorescence detection. The concentrations (mean +/- S.D.) of total homocysteine in plasma from 77 normal subjects, 44 male and 33 female adults, were 8.4 +/- 2.15 and 7.1 +/- 1.18 mumol/l, respectively. Serum concentrations were 8.8 +/- 2.6 mumol/l in males and 7.6 +/- 1.5 mumol/l in females.

Chromatography, High Pressure Liquid↗
PubMed1997

Hyperactivity and increased hydrogen peroxide formation in platelets of NIDDM patients.

Free radical activity may contribute to atherosclerotic lesions which in diabetic subjects may frequently lead to vascular complications. It is known that oxidative stress is associated to diabetes. Protein glycation and glucose oxidation could be possible source of free radicals. 28 non insulin dependent diabetic subjects (NIDDM) were examined. 20 healthy subjects matched for age, sex and for the presence of hypertension and hyperlipidemia were also studied. Hydrogen peroxide, measured by intracellular levels of the fluorescent 2,7-dichloro-fluorescein (DCF), was considered as indicative parameter of free radical production. The results showed that in resting platelets the basal level of hydrogen peroxide was significantly higher in diabetic subjects than in controls. Moreover, after stimulation with thrombin, collagen, phorbol myristate acetate (PMA) and platelet activating factor (PAF), platelets of diabetic subjects generated significantly higher amounts of hydrogen peroxide than controls. Moreover, platelet aggregation induced by adenosine 5'-diphosphate (ADP) and plasma beta TG levels were higher in diabetics than in controls. In diabetic patients platelet free radical production and functional activity are increased and therefore could play a role in the elevated thrombotic risk described in diabetes.

Adenosine Diphosphate↗
PubMed1992

Increased hydrogen peroxide formation in platelets of patients affected with essential thrombocythaemia (ET).

The basal platelet level of reactive oxygen species and their enhancement following stimulation by different agonists were determined in a selected group of patients with essential thrombocythaemia (ET). Activated platelets had lower levels of superoxide anion and higher intracellular concentrations of hydrogen peroxide than controls. Higher levels of lipid peroxidation induced by N-ethylmaleimide were also observed. Measurement of the most important enzymes generating and scavenging these reactive oxygen species revealed increased specific activities of NADPH-cytochrome c reductase and superoxide dismutase and a decrease in platelet catalase activity in patients with ET. Since an abnormal production of oxygen radicals seems to be implicated in various pathological conditions and aging processes, the increased amount of hydrogen peroxide found in platelets of patients could be involved in some of the platelet alterations described in ET.

Blood Platelets↗
PubMed1990

Platelets of patients affected with essential thrombocythemia are abnormal in plasma membrane and adenine nucleotide content.

The adenine nucleotides present in distinct cellular compartments of platelets of 27 patients affected with essential thrombocythemia have been measured. In order to quantify granule-bound nucleotides and adenylic cytoplasmic pool, platelets have been stimulated with thrombin or treated with increasing digitonin concentrations, respectively. Among patients, we have identified two groups: 12 patients (Group 1) had normal platelet level of ATP and ADP both in dense granules as well as in cytoplasmic pool. The other patients (Group 2) had granule ATP and ADP significantly lower and ATP/ADP ratio significantly higher than controls. In these patients an increase in hypoxanthine level, derived from metabolic ATP degradation occurring during stimulation, was observed. In addition, in the latter patients an increased resistance of plasma membrane to digitonin was shown, suggesting that membrane fluidity should be reduced owing to a modified cholesterol/phospholipid ratio.

Adenine Nucleotides↗
PubMed1990

[Evaluation of various hemorheological parameters in nonagenarians: evidence of an increase of fibrinogen].

Cardiovascular disease is the most frequent cause of mortality in the elderly. A reduced microvascular blood flow associated with an increase in atherosclerosis might contribute to age related increases in the incidence of ischemic vascular disease. In order to evaluate the effect of age on some haemorheological parameters, blood and plasma viscosity and fibrinogen have been measured in 10 healthy elderly subjects, aged between 88 and 96 years, compared with 15 healthy young subjects (mean age 37 years). Elderly subjects showed a significant increase in plasma fibrinogen (p less than 0.0005) and a trend to an increase in plasma viscosity, whereas no difference was present in blood viscosity. These data confirm that aging is associated with a greater deal of thrombotic risk factors, the most important of which seems to be fibrinogen.

Adult↗
PubMed1990

[Evaluation of various hemorheologic parameters in diabetes mellitus].

It has been speculated that changes in intrinsic blood flow properties may contribute to the evolution of vascular complications in diabetes mellitus. To verify this hypothesis we measured hematocrit, fibrinogen, plasma and blood viscosity in 30 diabetic patients and in 25 healthy volunteers. Diabetics showed blood and plasma viscosity and fibrinogenemia higher than healthy subjects, although only plasma viscosity and fibrinogenemia were statistically significant (p less than 0.001). Moreover the diabetic patients with the highest HbAlc values had a significant increase in plasma viscosity compared with the patients with lower HbAlc values (p less than 0.001), despite a similar fibrinogenemia. This study confirms the presence of hemorheological changes in diabetes mellitus and shows a correlation between plasma viscosity and metabolic control.

Adult↗
PubMed1989

[Hemorheological and coagulation aspects in plasmacytoma].

We reported the main rheological and coagulative features in seven patients affected with monoclonal gammapathy: four of them presented IgA class paraprotein, two IgM class paraprotein and one IgG class paraprotein. All presented increased plasma and serum viscosity. The four patients affected with IgA monoclonal paraproteinaemia underwent one plasma volume plasmapheresis. This procedure has been demonstrated to be useful and effective in reducing both plasma and serum viscosity.

Adult↗
PubMed1987

Platelet glucose metabolism in type I diabetic subjects.

In a group of 35 type I diabetics, platelet glycolytic and glycogenolytic flux have been measured. In type I diabetic platelets glucose uptake was significantly reduced. The quite normal lactate production was obtained by a faster utilization of stored glycogen in these patients. Specific activity of glycolytic enzymes was normal, in particular the levels and kinetic properties of soluble and membrane bound hexokinase. The rate of glucose flux through the hexose monophosphate shunt, measured either in resting or in arachidonic acid-stimulated platelets, was normal in diabetics. Kinetics of glucose transport across plasma membrane have also been determined. Km was significantly increased in diabetic patients. No changes was shown in Vmax. Modifications present in membrane organization of patients could involve glucose transport protein.

Adult↗
PubMed1987

Effect of diabetes mellitus on selected acid hydrolase activities in human platelets.

Platelets were isolated from blood donated by 57 diabetic subjects, 41 insulin-dependent and 16 non insulin-dependent, ranging in age from 19 to 78 years, and by 54 healthy non-diabetic subjects ranging from 19 to 63 years of age. The platelets were ruptured by sonication and resultant preparations assayed for their levels of activity of seven acid glycohydrolases. Platelets from diabetic subjects contained only 50% of the alpha-L-fucosidase activity and about 60% of the acid phosphatase, beta-D-galactosidase, and beta-D-glucosidase activities of platelets from non-diabetic individuals; the differences were statistically significant. N-acetyl-beta-D-glucosaminidase activity in platelets from diabetic subjects was reduced by about 15% from normal levels while beta-D-glucuronidase and alpha-D-mannosidase activities were similar to those from non-diabetic individuals. A comparison of the data from older insulin-dependent diabetic and normal subjects with a similar age distribution yielded identical results for the two groups in all enzymes tested except fucosidase. Platelets of non insulin-dependent diabetics and those from non-diabetic subjects of a similar age distribution appear to possess similar levels of these acid hydrolases. There was no difference in levels of these platelet acid hydrolases between males and females in either the diabetic or non-diabetic group. Within the diabetic group, there was no difference in these platelet acid hydrolase activities between subjects with retinopathy and without retinopathy. There was no correlation of the enzyme activity levels of platelets from diabetic subjects with concentration of glycosylated haemoglobin, serum triglycerides or serum cholesterol.

Acid Phosphatase↗
PubMed1985

Lactate overproduction in platelets of subjects affected with myeloproliferative disorders.

In platelets of patients affected with myeloproliferative disorders, glycolytic and glycogenolytic flux have been examined. Results of studies on glucose uptake, glycogen breakdown and lactate formation have been reported. No difference in glucose uptake between controls and patients was observed, but in patients a higher lactate formation was always noted in the presence or absence of exogenous glucose, in correlation with a higher glycogen breakdown rate. Results could be explained by modified regulation mechanisms on glycogen phosphorylase.

Adult↗
PubMed1984

Some aspects of platelet glucose metabolism in thrombocytosis due to myeloproliferative disorders.

Some aspects of the glucose metabolism were investigated in platelets of 11 healthy donors and 11 patients suffering from thrombocytosis due to myeloproliferative disorders. Out of all the glycolytic compounds measured in resting platelets, dihydroxyacetonephosphate and fructose 1,6 bisphosphate were significantly higher in cells of subjects with thrombocytosis. No difference was observed in the basic net flux of glucose through the hexose monophosphate shunt. Addition of arachidonic acid to platelets of patients with thrombocytosis had a very poor effect in stimulation of the hexose monophosphate shunt, whereas high values of activation were obtained in control platelets. Lactate production determined by collagen was found significantly higher in all patients. These data observed in platelets of patients could be explained by a decreased pool of metabolic adenine nucleotides.

Adult↗
PubMed1984

Platelet membrane fatty acids in thrombocytosis due to myeloproliferative disorders.

The fatty acid composition of platelet membranes has been analysed in patients with thrombocytosis due to myeloproliferative disorders, who had not taken any drugs. A significant increase in palmitic and oleic acid, together with a decrease in stearic, linoleic and arachidonic acids was observed. The fatty acid pattern of platelet membranes was also analysed in patients during treatment with ASA (acetylsalicylic acid). ASA ingestion completely normalizes the platelet content of palmitic acid and partially that of stearic and arachidonic acid, whereas it has no effect on the level of linoleic acid and raises that of oleic acid. The altered pattern of fatty acids observed in patients may interfere with platelet function by decreasing membrane fluidity. Treatment of patients with ASA seems to act on platelet membranes by partially normalizing the fatty acid composition.

Adult↗