Analysis of Platelet Membrane Glycoproteins in Myeloproliferative Disoroers

The platelet membrane glycoproteins (GP) of myeloproliperetion disorders(12 cases) were analyzed by SDS PAGE. In GP I peak there was no difference between normal and this disorders in the 125I incorporation rate but the percentage of GP I to all PAS stained peaks was reduced in chronic myelogenous leukemia (CML) but increased in primary thrombo-cythemia(PT) polycythemia vera(PV) and myelofibrosis (MMM). In GP m peak of CML, the increased percent of PAS staining and the decreased 125I incorporation rate were proved compared to the control. In other myeloproliferative disorders, it was shown that the percent of PAS staining was normal but 125I incorporation rate was decreased against GP III. To analyse the dissociation between PAS stain and 125I incorporation rate, the two dimensional electrophoresis was conduced with non reduced-reduced system. The autradiographic pattern of this electrophoresis disclosed seven 125I incorporated spots (GP Ia, Ib, Ic, IIa, IIb, III and IV) in normal platelets. GP Ib was exposed as an unclear spot in CML (4/6). GP IV appeared as a most dense spot in control but were divided in two spotsimain large and small satellite fragment in 4 of 6 CML and in one of PV and MMM. This findingsuggested a heterogeneity of membrane glycoprotein in these disorders.

Kinetic Study of Thrombogenesis on Stroke-Prone Spontaneously Hypertensive Rats (SHRSP). The Effect of Platelet-Inhibiting Drug and Vitamin E

The increase of platelet production was demonstrated in stroke-prone SHR(SHRSP) after 10 weeks of age, probably due to increased platelet consumption compared with those in stroke-resistant SHR(SHRSR)(Koganemaru, S., et al. Thrombus. Haemostas.(Stuttgart)38:139, 1977). We extended our study to see the effect of aging, blood pressure, platelet-inhibiting drug and vitamin E(Vit.E) on this kinetic change. SHRSP(A1-sbF37-39) and SHRSR (BlF36-38) with matched age (5 weeks, 10 weeks and 9-12 months) and sex were used. The maximum uptake of 75se-methionine(75SeM) into platelets was not affected in both salt loading group and Clonidine group in SHRSP. A significant decrease was observed in dipyridamole group (0.096 ± 0.020, p<0.05). The platelet survival time was shortened in Vit. E deficient group of SHRSR; 3.0 days at 9-10 weeks. In Vit.E sufficient group of SHRSP. the platelet survival time was corrected to normal. The maximum uptake of 75SeM increased in both Vit.E deficient group of SHRSP (0.119 ± 0.010 vs 0.192 ± 0.030, p<0.01) and SHRSR (0.071 ± 0.016 vs 0.119 ± 0.018, p<0.01). The increased platelet production was not affected by blood pressure but it can be suppressed by treating with dipyridamole or giving Vit.E before 10 weeks of age.

Ultrastructural studies on the surface coat of human platelet aggregated by polylysine and dextran

Positively charged macromolecule, polylysine (mol. wt. 15,000; 23,000; 180,000) could induce the platelet aggregation in low concentration but high concentration was required in the case of neutral macromolecule, dextran (mol. wt. 40,000; 250,000; 2,000,000). The larger molecules of polylysine and dextran were more effective in inducing platelet aggregation. In the dextran-induced aggregation, positively charged Thorotrast particles on the cell surface did not decrease significantly. On the other hand, the surface membranes of platelets aggregated by polylysine were essentially devoid of bound particles. Heparin inhibited the polylysine-induced platelet aggregation but not the dextran-induced aggregation. These findings suggested that polylysine induced aggregation more effectively than dextran by reducing the negative surface charge and giving stronger adsorption force on cell surface. In platelet-rich plasma, polylysine elicited the release reaction of 14C-serotonin but dextran did not. Possible mechanism by which polylysine could elicit the release reaction is the formation of more tightly packed platelet aggregate than that by dextran in the presence of the low calcium ion concentration in citrated platelet-rich plasma. Average distance between plasma membranes of aggregated platelets, however, did not vary with the degrees of polymerization of these macromolecules.

Glutathione reductase deficiency in a kindred with hereditary spherocytosis

A kindred with hereditary spherocytosis was found to have erythrocyte glutathione reductase deficiency. The glutathione reductase was evaluated enzymatically and immunologically. The enzyme activity could not be restored either by flavin adenine dinucleotide (FAD) in vitro, or by oral administration of FAD. Kinetic and electrophoretic studies, heat stability tests, and pH curves revealed no evidence of a varient enzyme. The results of electroimmunodiffusion and neutralization tests using an antiserum indicated that the deficiency is caused by a diminished production of enzyme protein. Hereditary spherocytosis and glutathione reductase deficiency traits segregated independently. The amount of reduced glutathione in the erythrocyte was normal, and the deficiency state without hereditary spherocytosis was asymptomatic. All deficient members in this kindred were heterozygous and the residual enzyme activity in the heterozygote might be sufficient to maintain the reduced glutathione level to prevent oxidative stress.