Platelet aggregation, ATP release and cytoplasmic Ca2+ movement: the effects of cloricromene.

A placebo-controlled, double-blind, randomized, cross-over study was performed in 24 healthy volunteers. 12 volunteers received Cloricromene (100mg gastroresistant capsules twice a day) for 7 days, the other volunteers received identical placebo capsules. Subsequently, after a 7-day wash-out period, at day 15, each subject received the other treatment. Blood samples were taken on days 1 and 15 (1st day of each treatment) as well as on days 7 and 21 (7th day of each treatment) before the morning drug administration and 2 and 4 hours later. Platelet aggregation and ATP secretion were studied in whole blood (WB) using ADP and collagen as stimulating agents. Ca2+ fluxes were studied in aequorin…

ABNORMALLY HIGH THROMBOXANE BIOSYNTHESIS IN HOMOZYGOUS HOMOCYSTINURIA. EVIDENCE FOR PLATELET INVOLVEMENT AND PROBUCOL-SENSITIVE MECHANISM.

Homocystinuria due to homozygous cystathionine beta-synthase deficiency is an inborn error of metabolism characterized by a high incidence of thrombosis and premature atherosclerosis. We evaluated TXA2 biosynthesis in vivo and several in vitro tests of platelet function in 11 homocystinuric patients and 12 healthy controls. In vitro, patients' platelet aggregation was within control values as were TXB2 formation, fibrinogen binding, and ATP secretion in response to thrombin. In contrast, the urinary excretion of 11-dehydro-TXB2, a major enzymatic derivative of TXA2, was > 2 SD of controls in all patients (1,724 +/- 828 pg/mg creatinine, mean +/- SD, in patients vs. 345 +/- 136 in controls, …

Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 9

In this contribution, new data concerning bryophytes, fungi, and lichens of the Italian flora are presented. It includes new records and confirmations for the bryophyte genera Encalypta, Grimmia, and Riccia, for the fungal genera Hericium, Inocybe, Inocutis, Pluteus, and Russula, and for the lichen genera Bryoria, Farnoldia, Hypocenomyce, Lecania, Paracollema, Peltigera, Sarcogyne, and Teloschistes.

Increased plasminogen activator inhibitor antigen levels in diabetic patients with stable angina

PAI-1 antigen, tPA antigen and thrombin - antithrombin III complexes (TAT) levels were measured in 10 males with stable angina and type-II diabetes mellitus and in 16 males with stable angina without diabetes or other risk factors (hyperfibrinogenaemia, hyperlipidaemia, diabetes, hypertension, smoking and obesity) known to increase PAI levels. Ten healthy men of equivalent age served as controls. Because only diabetics with coronary artery disease (CAD) showed a decreased fibrinolytic capacity, a second study was performed on the 16 non-diabetic CAD patients to determine whether submaximal workload induces significant changes of tPA and PAI levels. TAT levels were increased in CAD, and sign…

Thrombin-antithrombin III complexes in type II diabetes mellitus.

Several studies suggest that diabetes is associated with a hypercoagulable state. Therefore determination of thrombin-antithrombin complex (TAT) could represent a sensitive parameter for specific detection of a latent activation of the clotting system. The present study documents increased plasma TAT in a heterogeneous group of non-insulin-dependent diabetic patients. The finding of increased TAT levels both in diabetic patients with vascular complications and in vascular disease patients without diabetes suggests a relationship between existing vascular disease and the hemostatic mechanism that produces augmented thrombin activity. In acute vascular occlusions the presence of diabetes seem…

Platelet Function During Ticlopidine and Eicosapentaenoic Acid Administration in Patients with Coronary Heart Disease

Antiplatelet drugs have been reported to be useful in unstable angina. This study was designed to investigate the effects of simultaneous administration of ticlopidine and eicosapentaenoic acid (EPA) on platelet function in coronary heart disease (CHD) patients. Ticlopidine significantly reduced platelet aggregation induced by ADP and collagen with no effect on arachidonate metabolism. The aggregation responses to collagen, ADP and arachidonate were not altered significantly by EPA (as fish oil) intake whereas thromboxane A(2) formation was reduced, but not completely inhibited. Combined therapy seems to achieve a more marked degree of inhibition of aggregation together with a fall in the u…

Platelets, eicosanoids and aging.

Influence of Metabolic Control on Thromboxane Biosynthesis and Plasma Plasminogen Activator Inhibitor Type-1 in Non-insulin-dependent Diabetes mellitus

SummaryWe have previously shown that tight metabolic control by insulin therapy reduced thromboxane-dependent platelet activation in noninsulin-dependent diabetes mellitus (NIDDM) patients. The present study was undertaken to determine whether a similar effect could be obtained without switching diabetics in secondary failure to insulin treatment. For this purpose, we gave strict diet and exercise advise program and adjusted on a weekly basis the oral antidiabetic therapy (glipizide) that 26 patients with NIDDM had been given over the previous months.Basal measurements of urinary ll-dehydro-TXB2 and PAI-1 confirmed previous findings of enhanced levels of these parameters in NIDDM patients w…

Climate change fosters the decline of epiphytic Lobaria species in Italy

Similarly to other Mediterranean regions, Italy is expected to experience dramatic climatic changes in the coming decades. Do to their poikilohydric nature, lichens are among the most sensitive organisms to climate change and species requiring temperate-humid conditions may rapidly decline in Italy, such in the case of the epiphytic Lobaria species that are confined to humid forests. Our study, based on ecological niche modelling of occurrence data of three Lobaria species, revealed that in the next decades climate change will impact their distribution range across Italy, predicting a steep gradient of increasing range loss across time slices. Lobaria species are therefore facing a high ext…

Fibrinogen and von Willebrand factor in type II diabetes mellitus

A hypercoagulable state may contribute to the formation of early vascular lesions in diabetes. The von Willebrand factor is required for the attachment of platelets to the subendothelium; fibrinogen is required for platelet aggregation. This study was designed to assess in type II diabetic patients plasma levels of fibrinogen and von Willebrand factor to see if these variables are associated with platelet aggregation responses to adenosine diphosphate (ADP). Fibrinogen and the von Willebrand factor were significantly increased in diabetics but only fibrinogen was significantly related to platelet aggregation for ADP. Strict metabolic control does not reduce the increased concentrations of t…

Increased thromboxane biosynthesis in type IIa hypercholesterolemia.

BACKGROUND Increased platelet thromboxane (TX)A2 production has been described in type IIa hypercholesterolemia. To verify the relevance of these capacity-related measurements to the actual rate of TXA2 biosynthesis in vivo, we studied the urinary excretion of its major enzymatic metabolites in 46 patients with type IIa hypercholesterolemia and 20 age-matched controls. METHODS AND RESULTS Urinary 11-dehydro-TXB2 and 2,3-dinor-TXB2 were measured by previously validated radioimmunoassays. The excretion rate of 11-dehydro-TXB2 was significantly (p less than 0.001) higher in patients (68.7 +/- 35.1 ng/hr, mean +/- SD) than in controls (22.4 +/- 9.4 ng/hr), with metabolite excretion greater tha…

Thromboxane biosynthesis, neutrophil and coagulative activation in type IIa hypercholesterolemia

SummaryThromboxane (Tx) A2 biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because blood clotting activation is an important component of the inflammatory response, involved in the initiation and progression of atherosclerotic plaques, we have investigated TxA2 biosynthesis, neutrophil activation and thrombin generation in 24 patients with type IIa hypercholesterolemia.Urinary 11-dehydro-TxB2, was significantly higher (p =0.0001) in patients than in 24 sex- and age matched healthy subjects. Similarly, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complexes and plasma elastase were significantly higher in patients than incontrols. Urinary…