Separable function of platelet release reaction and clot retraction.

Amiloride, a known Na+/H+ exchange inhibitor, inhibited platelet serotonin release in a dose-dependent manner (100 microM for 50% inhibition, and 1mM for the nearly complete inhibition), although amiloride (1mM) accelerated clot retraction when it was measured at decreased platelet concentration. On the contrary, cytochalasin B (10 micrograms/ml) accelerated platelet serotonin release, but it inhibited clot retraction. These results demonstrate that release reaction and clot retraction, both of which are important processes involved in platelet activation, can be functionally separated.

A defect of platelet release reaction in a patient with SLE: impaired platelet aggregation induced by phorbol ester with a normal phosphorylation of 40K protein.

A 37-year-old female who suffered from SLE had a bleeding disorder. At the time of initial evaluation, the main disease demonstrated was a delta-storage pool deficiency. After this improved, a marked decrease of aggregation still remained, when induced by either ADP, epinephrine, collagen, A23187, thrombin, or PAF-acether.

The platelet protein phosphorylation induced by a monoclonal antibody against human platelets (TP82).

In human platelets, a monoclonal anti-human platelet antibody (TP82) induced platelet aggregation and release of granules (i.e., serotonin, platelet factor 4, N-acetyl-beta-D-glucosaminidase).

A novel leukocyte differentiation antigen: two monoclonal antibodies TM2 and TM3 define a 120-kd molecule present on neutrophils, monocytes, platelets, and activated lymphoblasts.

We produced two hybridomas by fusion of mouse myeloma cells with splenocytes from a mouse immunized with the THP-1 human monocytoid leukemia cell line. Two cloned hybridoma cell lines, designated as TM2 and TM3, were obtained. They secreted antibodies against a unique cell surface antigen expressed on all normal peripheral blood monocytes, neutrophilic granulocytes, platelets, and mitogen-induced lymphoblasts, some cells from patients with immature-type lymphoid leukemias.

The platelet activation induced by wheat germ agglutinin.

In human platelets, wheat germ agglutinin (WGA) induced serotonin release without cell agglutination. WGA induced the phosphorylation of both 40-kDa and 20-kDa proteins in a parallel manner, and at least, the phosphorylation of 40-kDa protein was preceded by transient formation of endogenous diacylglycerol (DG) accompanied by a decrease in phosphatidylinositol (PI). Both phosphorylation of these two proteins and serotonin release were inhibited by prior treatment of platelets with dibutyryl cyclic AMP, W-7, or TMB-8.

A monoclonal anti-human platelet antibody: a new platelet aggregating substance.

A monoclonal anti-human platelet antibody, TP82, is described, which caused irreversible aggregation of platelets in association with the release of adenosine triphosphate or [14C] serotonin, and which inhibited ristocetin-induced agglutination. Immunofluorescence assay showed that the antibody binds to platelets, megakaryocytes, and common acute lymphoblastic leukemia cells. The antibody (IgG1) immunoprecipitated a polypeptide of 23,000 daltons with an isoelectric point of about 7.

Protection by vaccination against bovine leukemia virus infection in sheep.

Four preparations were tested as potential vaccines to protect sheep against bovine leukemia virus (BLV) infection. Purified glycoprotein (gp) 51 and protein (p) 24 antigens from the virus and glutaraldehyde-fixed fetal lamb kidney (FLK) cells chronically infected with BLV or sheep fibroblasts transformed with BLV (SF-28 cells) were used to inoculate 12 sheep. Each vaccine was given 3 times 2 and 4 weeks apart to 3 sheep.

Interaction of Solanum tuberosum agglutinin with human platelets.

Solanum tuberosum agglutinin (STA) binds to the surface of human platelets and leads to their agglutination. Lectin staining shows that 125I-STA most intensely labels a major platelet membrane glycoprotein identified as GPIIIa followed by GPIV . STA does not induce release reaction, TXB2 formation or platelet protein phosphorylation.

A case of tuberculous epididymitis associated with Addison's disease.

A 68-year-old man was admitted to the hospital because of loss of appetite, easy fatigability, and skin pigmentation. Physical examination revealed that the bilateral epididymides were enlarged and hard without tenderness. At 7 a.

Purification and hemagglutinating properties of egg drop syndrome 1976 virus.

We purified three populations of virus particles, F7, F9 and F17, with buoyant densities of 1.34, 1.33 and 1.

Myocarditis in Behcet's disease--a case report and review of the literature.

A 33-year-old male with Behçet's disease developed congestive heart failure without apparent etiology. Although an electrocardiogram and thallium-201 scintigraphy showed myocardial ischemic damage, there were no abnormalities detected in the coronary arteries. Echocardiographic studies and a left ventriculogram were compatible with congestive cardiomyopathy.