thrombocytopoietin

Successive chromatographic procedures made it possible to isolate thrombocytopoietin from the serum of thrombocytopenic rats. The following steps were taken: DEAE-cellulose phosphate chromatography, Sephadex chromatography, exclusion chromatography on DEAE-Sephadex A-50 gel. The apparent molecular weight of thrombocytopoietin was about 48,000 daltons. Like erythropoietin, thrombocytopoietin is a glycoprotein, its molecular weight is similar. A single form is obtained only when the different purification steps last less than 10 days...

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Thrombocytopoietin seems to be only partially responsible for the regulation of platelet production. We determined precisely the differences between a second thrombocytopoiesis-stimulating factor (TSF2), and thrombocytopoietin (TSF1) and erythropoietin (Epo). Fractionation was carried out, first on a DEAE-cellulose phosphate column and then on a Sephadex G-75 column. Thrombocytopoietic activity in the various fractions was assessed using 75Se-methionine platelet incorporation into normal recipients. Epo concentrations were determined using a radioimmunoassay...

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The effects of plasma thrombocytopoietin are investigated in test mice against the background of nonselective beta adrenergic impacts. The changes in the thrombocytopoiesis are accounted for by the thrombocytes count and by the percentage of 75selenomethionine incorporated in the newly-formed thrombocytes. Plasma thrombocytopoietin is found to stimulate markedly thrombocytopoiesis on the background of beta-adrenergic stimulation with isoprenaline. Pretreatment with propranolol totally prevents this stimulation...

The influence of neonatal thymectomy on the number of thrombocytes, bone-marrow megakaryocytes (MKC) and activity of plasa thrombocytopoietin(TP) was studied in male rats 60 days after the manipulation--under normal and extreme (acute thromobocytopenia) conditions. It was established that under normal conditions neonatal thymectomy (NT) diminished the number of thromobocytes, the percentage of incorporated 75 selenomethionine in newly formed thromobocytes, the total number of MKC and their single stages--I, II, III, IV...

On the basis of our long-term experience, presented are the current clinically useful methods for determining erythropoietin, the granulocytopoiesis growth factor and thrombocytopoietin with the results in their use. Facts are shown, concerning the long-used method of determining erythropoietin through the use of the biological test on polycythemic mice. In our conditions, mice treated with physiological solution (negative controls) have a Fe-59 incorporation below 0.5% of the given dose, while 0.2 units of the international erythropoietin standard (positive control) increases that incorporation to 3...

The influence of insulin on the number of thrombocytes of male and female rats as well as on the percentage of 75Selenomethionine (75Se-M) incorporated, on bone marrow megakaryocytes and thrombocytopoietic activity of the plasma was studied under normal conditions. It was established that a 3-day administration of insulin induced in both go groups of rats an increase in thrombocyte number, in the percentage of incorporated 75Se-M, in bone marrow megakaryocytes as well as in their total number and in all stages from I to IV with shift to mature cellular forms (III and IV stages)...

The influence of estradiol, estriol and progesterone was studied on basic parameters of thrombocytopoiesis and thrombocytopoietic activity of plasmas of female rats. It was established that the investigated hormones increased highly the number of thrombocytes, the percentage of 75-selenomethionine incorporated in newly formed thrombocytes and the total number of megakaryocytes. Thrombocytopoietic activity of the plasma was raised considerably only in rats, injected with estradiol, but the remaining hormones did not induce significant changes in this activity...

The assumption that thrombocytopoietin preparations prepared in our own laboratory can prevent the decrease of the number of thrombocytes in the peripheral blood of animals irradiated by a sublethal dose of gamma-ionizing rays was tested in an experiment on mice. Two preparations were tested: one, with an influence on stem cells, which directs them in the direction of megacariocyte differentiation (Smp), and the other one which is essential for the endomitosis and production of thrombocytes (Stp). The results undoubtedly indicated that a decrease in the number of thrombocytes occurred in the peripheral blood of animals following irradiation without the use of the preparations mentioned above, and was mostly emphasized after 9 days...

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