Hiroyuki Nozaki

Reduction of platelet aggregation induced by euglycaemic insulin clamp

SummaryTo examine the effect of serum insulin independent of the level of blood glucose in vivo on platelet aggregation in healthy individuals, a euglycaemic insulin clamp was applied up to 4 h. During the clamp, blood glucose at 5.0 mmol/l and insulin levels at 100 μU/ml were maintained. Blood samples were drawn before, 2 and 4 h after the start of the insulin clamp. The platelet aggregation induced by 1 μmol/l and 2 μmol/l ADP, 1 μg/ml collagen and 2.7 μmol/l epinephrine was measured in the blood samples. Platelet aggregation induced by adenosine diphosphate, collagen and epinephrine in the 4 h sample was significantly reduced from the pre-clamp value of 8.4% to 3.9% (p<0.05), 26.2% to 7.0% (p<0.01) and 31.8% to 9.1% (p<0.01), respectively. On the other hand, when the same individuals were infused with physiological saline and blood glucose (4.4 mmol/l) and insulin level (10 mIU/l) were kept within normal values, there was no difference between the values of induced platelet aggregation in samples drawn before and during the insulin infusion. It was concluded that hyperinsulinaemia reduces platelet aggregation in vivo when euglycaemia was maintained.

Lipid content of human platelets quantitated by thin-layer chromatography in combination with flame ionization detection

The lipid contents of human platelets from twenty-one healthy adults were analysed using thin-layer chromatography in combination with flame ionization detection. The weight per cent of neutral lipids in human platelets was 14.6%, which consisted mainly of free cholesterol, that of phosphatidylethanolamine 24.9%, phosphatidylserine plus phosphatidylinositol 6.8%, phosphatidylcholine 35.2% and sphingomyelin 18.6%. Free cholesterol in 10(8) platelets was estimated as 7 micrograms and phospholipids as 46 micrograms from calibration standards. The reproducibility was satisfactory and the procedure could be performed quickly and simply.

Platelet volume and intraplatelet adenine nucleotides in various hematologic disorders

By recent advanced techniques, blood platelets have proved to be varied in size and metabolism in various hematologic disorders. We examined platelet volume and intraplatelet adenine nucleotides in 36 patients with various hematologic disorders in order to clarify the quantitative platelet abnormalities. Platelet volumes were smaller in patients with acute leukemia and aplastic anemia, and larger in patients with immune thrombocytopenic purpura (ITP). The amount of intraplatelet ADP was decreased and ATP/ADP ratio was increased in acute leukemia, aplastic anemia and myeloproliferative disoders (MPD), which strongly suggested the presence of storage pool deficiency in these patients. Intraplatelet ADP per volume was decreased in acute leukemia, aplastic anemia and MPD, and ATP per volume was decreased in aplastic anemia. ATP content was increased in ITP in proportion to the increased platelet volume. These parameters were examined in 36 patients with the following hematologic disorders: 7 acute leukemia treated with cytotoxic chemotherapy, 5 aplastic anemia, 3 paroxysmal nocturnal hemoglobinuria (PNH), 9 immune thrombocytopenic purpura (ITP), 5 hypersplenism and 7 myeloproliferative disorders (MPD).

Case Report: The effect of a Chinese herbal medicine, BG-104 in two HIV positive hemophiliacs

The BG-104, a Chinese herbal medicine, has been reported to restore decreased plasma superoxide scavenging activity.This report showedin vivo effect of BG-104 on two patients with hemophilia A infected with human immunodeficiency virus by infusions of the concentrated Factor VIII. Both patients, showed a peripheral CD4+ T-lymphocytopenia for more than half a year. BG-104 was administered daily and follow-up observations were continued for 3 years. The number of CD4+ T-lymphocytes remained relatively constant during BG-104 treatment without disease progression.

Increased Collagen Synthesis of Bone Marrow Fibroblasts by Materials Released from Platelets of Chronic Granulocytic Leukemia and Polycythemia vera

Collagen synthesis stimulated by materials released from platelets (MRFP) of patients with chronic granulocytic leukemia (CGL) and polycythemia vera (PV) was measured in human bone marrow fibroblasts derived from normal individuals. The MRFP of patients with CGL and PV stimulated normal fibroblast collagen synthesis significantly compared to the response from normal MRFP. Platelets derived from patients with CGL and PV may have some factors that dramatically stimulate collagen synthesis which is relevant to the frequently observed myelofibrosis in these diseases.

Clinical Evaluation of Combination of Cefmetazole and Piperacillin in the Treatment of Infections in Patients with Acute Leukemia

27 episodes of infection in patients with acute leukemia were treated with combination of cefmetazole and piperacillin. Causative bacteria were isolated in each infection. The patients were treated with 6 g cefmetazole and 15 g piperacillin per day in three divided doses. Among the episodes of infection, 21 (78%) of 27 responded to cefmetazole and piperacillin. Adverse reactions were skin rash in 2 patients, transient elevation of serum glutamic-pyruvic transaminase in 3 patients and elevation of creatinine in 1 patient. Cefmetazole and piperacillin appear to be an effective combination, with acceptable adverse reactions, for the empiric therapy of infection in patients with acute leukemia.

Platelet aggregation and intraplatelet adenine nucleotides in diabetic retinopathy.

Twenty non-diabetic controls, 50 diabetics without retinopathy and 29 diabetics with retinopathy, all well-matched age groups, were studied in males and females, respectively. Moreover, diabetic patients with retinopathy were divided into the following two subgroups: mild retinopathy and severe retinopathy. Platelet aggregation was elevated in the male diabetics with mild or severe retinopathy. There was no difference in platelet volume between the groups. Intraplatelet ADP contents were significantly decreased in the female diabetics with severe retinopathy showing no high platelet aggregability. There was no significant difference in intraplatelet ATP contents between groups. These results indicated not only that platelet aggregation might be generally high in the diabetics with retinopathy, but also that dense granule release might occur readily in vivo in the female diabetics with severe retinopathy and therefore platelet aggregation was not elevated in the group.