TROMBOTSITOPOETINA

From Big Medical Encyclopedia

TROMBOTsITOPOETYNY (thrombocytes] + the Greek poietikos creating, making) — the humoral substances stimulating formation of thrombocytes.

Yamamoto in 1957, studying effect of the blood serum taken from people after blood loss on a hemogenesis of rabbits, established that in blood of rabbits increase in number of thrombocytes (cm) is observed.

He assumed that blood serum of people contains the humoral factor stimulating a thrombocytopoiesis (see the Hemopoiesis). This factor received the name of a trombotsi-topoetin.

Further presence of T. in blood it was established in an experiment at animals after administration of antithrombocytic serum by it, after a splenectomy (see), at a thrombocyte-fereze (see the Plasma exchange), an aseptic inflammation, impact of ionizing radiation. T. were found also normal in serum and a blood plasma, in urine, in extracts of a spleen, limf, nodes, a liver. In a wedge, conditions of T. most often find in patients with thrombocytopenia (see).

One of factors of regulation of maintenance of T. the quantity of the circulating thrombocytes is (inverse relation of T is noted. from quantity of the circulating thrombocytes: the more the quantity of thrombocytes, the are lower the maintenance of T. and vice versa). In an experiment it was shown that T. appear in blood earlier, than otkhmechatsya morfol. changes of cells of a thrombocytopoiesis. Intensity of changes of a thrombocytopoiesis is in direct dependence on a dose and duration of introduction of T. Other indicators of blood and marrow at the same time significantly do not change.

Existence of T. in an organism is determined by most of researchers indirectly, by increase in number of thrombocytes in blood. Kelemen's method and soavt is most often applied. To mice weighing 20 g enter once into a tail vein the examinee material (blood serum of patients with thrombocytopenia) of 0,2 ml \thrombocytes count before its introduction and the 48th hour later. Reaction is considered positive if the number of thrombocytes increases by 30% and more. Other method of a research T. it is based on size discrimination of thrombocytes. It is shown that again formed thrombocytes have the big sizes, than «old». Emergence of thrombocytes of the big sizes is a sign of stimulation of a thrombocytopoiesis. In a crust, time for determination of T. use marked drugs — radio sulfate (85S) and selenometionin (75Se), to-rye enter intravenously. Joining in the developing megacaryocytes, they appear in again formed thrombocytes. At stimulation of a thrombocytopoiesis increase in number of marked thrombocytes is observed.

Nature of T. it is studied insufficiently, in a chemically pure look they are not allocated. According to a number of researchers, T. — - substances of the proteinaceous nature, are not dialyzed, digested trypsin, are sensitive to heating, collapse at storage, at an electrophoresis migrate in globulinovy fraction. The fraction containing T., it is possible to allocate from the blood received after bloodletting; it contains three amino acids (alanine, serine, valine), is its part glitserol and two fat to - you. Nek-ry researchers consider that T. termostabilna belong to lipids, do not lose activity at pH 5,5. Therefore existence of several thrombopoietic active factors possessing a promoting effect on proliferative activity of megacaryocytes, their maturing and an exit of thrombocytes from marrow in blood is not excluded.

Question of the place of formation of T. in a crust, time finally it is not solved. However a number of researchers consider the main place of their education a spleen and a liver; there are data on education them in marrow.

T., apparently, exert impact on the hemopoietic fabric. Most of researchers consider that T. affect the stem cell of marrow sensitive to T., stimulating its differentiation in the direction of a thrombocytopoiesis.

Bibliography: Abesadze A. I., In

robyev O. Ya. and Iosava G. G. Regulation of a thrombocytopoiesis, Tbilisi, 1978; To and x e t e l and d z e M. G. Endogenous regulators of a thrombocytopoiesis, Stalemate. fiziol. and ekspery. ter., No. 2, page 84, 1975; Markosyan A. A. and Putin c e in and E. G. Trombotsitopoetina, Usp. fiziol. sciences, t. 1, No. 1, page 55, 1970; M about-syagina E. N and Kakhetelid-z e M. G. Trombotsitopoez, in book: A normal hemopoiesis and its regulation, under the editorship of N. A. Fedorov, page 489, M., 1976; Tsygankova V. A. and Rudakov I. A. Methods of a research of thrombopoietic activity of blood, La borate. business, No. 2, page 94, 1972; To r i z-s a F., G e r g e 1 at G. a. R a k K. Megakaryocyte response in posthaemorrhegic thrombocytosis o! mice, Acta haemat. (Basel), v. 39, p. 112, 1968;

McDo nald T. P. The hemagglutination-inhi-bition assay for thrombopoietin, Blood, Y. 41, p. 219, 1973; Odell T. T. Regulation of the megakaryocyte-platelet system, in book: Regulation of organ and tissue growth, ed. by R. J. Goss, p. 187, N. Y. — L., 1972; Schulman I. o. Studies on thrombopoiesis, II. Assay of human plasma thrombopoietic activity, J. Pediat., v. 66, p. 604, 1965; Steinberg B. o. Thrombocytic and thrombopenic factors in normal human serum, Acta haemat. (Basel), v. 33, p. 341, 1965.

T. A. Prigozhina.

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