Draga Creter

The effect of pH on platelet and coagulation factor activities

After observing that lavage of the stomach with alkaline solutions has a beneficial effect on the control of gastric hemorrhage, we examined the platelet and coagulation factor activities under conditions of lower and elevated pH. The results showed that change of the pH from acidosis to 7.0 and even to slight alkalosis induces platelet aggregation, platelet calcium and serotonin release, as well as platelet factor II availability. The prothrombin and partial thromboplastin times approached normal levels, whereas the fibrinogen level did not change significantly. The results obtained may serve as an explanation for the control of the intragastric bleeding in patients treated by maintenance of their gastric pH at 7.0.

Elevated Thrombocyte Calcium Content in Uremia and Its Correction by 1α(OH) Vitamin D Treatment

Intracellular calcium plays an important role in the regulation of platelet function. It has also been demonstrated that platelet functions are impaired in uremia. A rise in intracellular calcium has

Inhibition of platelet aggregation by contrast media.

The effect of 30% Urografin on platelet aggregation induced by adenosine diphosphate (ADP), epinephrine, and arachidonic acid was examined. In vivo and in vitro experiments in 10 nondiabetic subjects and in vitro experiments in 7 diabetic-uremic patients showed a statistically significant decrease in platelet aggregation 20 minutes after in vitro incubation or in vivo infusion with Urografin. Urografin concentration was about 2.4-2.5%. The possibility of bleeding induced by contrast media and the connection with acute renal failure in diabetic-uremic patients are discussed.

Tissue plasminogen activator levels in different types of polycythemia.

Abstract: The plasma level of tissue plasminogen activator antigen (t‐PA‐Ag) was examined in 86 patients with polycythemia (29 polycythemia vera, 11 secondary polycythemia and 46 with spurious polycythemia) and 24 healthy volunteers. Tissue plasminogen activator antigen was significantly decreased in patients with polycythemia vera in comparison with healthy controls. On the other hand, in patients with spurious polycythemia and secondary polycythemia t‐PA‐Ag concentration was significantly increased. There was no significant difference in t‐PA‐Ag levels in polycythemic patients with or without thromboembolic disease. A significant correlation was detected between t‐PA‐Ag level and hemoglobin or hematocrit concentration in patients with polycythemia vera (p = 0.02, r = 0.43). However, in patients with secondary polycythemia and spurious polycythemia, no significant correlation between t‐PA‐Ag and hemoglobin level was found. Plasminogen activator inhibitor (PAI) levels in patients with polycythemia vera and healthy volunteers did not differ significantly.

Platelet aggregation in diabetic retinopathy.

Platelet aggregation in diabetic retinopathy was investigated in a group of 25 patients. An enhanced activity induced by epinephrine and arachidonic acid was found in this group as compared with the controls, whereas in adenosine diphosphate (ADP) platelet aggregation no differences were observed. Spontaneous aggregation was found in 8% of the diabetic retinopathy cases.

Platelet Functions Before, During and After Labor

Platelet functions were evaluated in 20 healthy pregnant women in the last months of pregnancy, during labor, and 5-12 weeks after labor. The results showed an increased platelet count, bleeding time and nitroblue tetrazolium (NBT) test, as well as an increased plasma calcium level postlabor. ADP- and epinephrine-induced aggregation during labor was markedly decreased, followed by a statistically significant increase postlabor. These findings are in correlation with the high incidence of thromboembolic phenomena occurring postlabor.

A Simple and Rapid Platelet Calcium Determination

A simple and rapid method for platelet calcium determination by atomic absorption spectrophotometry is described. The results in normals and in May-Hegglin anomaly are given.

Extensive Pharyngeal Hemorrhage Induced by Dipyridamole

An extensive hemorrhage in the pharynx appeared in association with dipyridamole administration to a diabetic patient. The hemorrhage caused dysphagia and subsided when the drug was discontinued. Coagulation tests were normal except for a decreased platelet aggregation. Platelet factor 3 and the aggregation tests with adenosine diphosphate and epinephrine were abnormal during the hemorrhagic event and returned to normal after discontinuation of the drug.

The Fibrinolytic Pathway in the Human Fetus

The fibrinolytic pathway and the protease inhibitors in 12 to 24-and 24-to 36-week-old fetuses were examined and compared with full-term newborns. The activity of the fibrinolytic system, as well as the values of the protease inhibitors approach the normal values progressively with the embryonic maturation.

The in vitro effect of pirprofen on the surface ultrastructure and function of human platelets

SummaryThe in vitro effect of pirprofen (Rengasil), an antiinflammatory agent, on the surface ultrastructure and function of human platelets was examined and compared with that of acetylsalicylic acid (Aspirin, ASA), and diclofenac sodium (Voltaren, DS). Incubation with pirprofen induced formation of long, neddle-shaped pseudopodia, a phenomenon observed also after incubation of the cells with DS. In contrast with ASA and DS, pirprofen induced a marked increase in platelet protein synthesizing capacity. The drug decreased the platelet aggregation to a degree similar to that of ASA and DS. The release of platelet factors 3 and 4 and the level of β-thromboglobulin following incubation with the drug remained unaltered.