[Role of the non-peptide thymic factor--hypoxanthine system in the proliferation of mature thymocytes of mice and rats]. / Vlyianye khymycheskoi modifykatsyy ostatkov arhinina fibrinohena i eho DH-frahmenta na ksorost' hidroliza étukh belkov plazminom.

The incorporation of [8-14C]hypoxanthine radioactive label into the nucleic acids of the mature thymocytes (that do not bind peanut agglutinin) of CBA mice and Wistar rats and the action of non-peptide thymic mitogenic factor (factor) on this process have been studied. It was shown, that the factor, shifting AMP catabolism towards hypoxanthine accumulation, accelerated by 50% the incorporation of hypoxanthine radioactive label into nucleic acids during 3-hour incubation. It is concluded that the factor being an activator of the hypoxanthine accumulation, abrogates the purine limits in thymocytes and activates the "salvage pathway" of purine synthesis which is the primary pathway in thymocytes. The factor is assumed to act as the mitogen on one of the stages of nucleic acids or nucleotides synthesis, but not to act on the guanine-hypoxanthine phosphoribosyl transferase. It was shown that the intrathymocyte ratio of hypoxanthine and factor concentrations (hypoxanthine/factor) is higher in rats than in mice. The dependence of proliferative activity on relative levels of both substances was revealed. The stimulation of cell proliferation by the system: factor--hypoxanthine is one of the mechanisms of thymus regeneration at the expense of mature thymocyte population.

[Intrathymic regulation of proliferation of medullary thymocytes in CBA mice]. / Vnutrishn'otymichna rehuliatsiia proliferatsiï meduliarovykh tymotsytiv myshei liniï CBA.

The action of non-peptide mitogenic factor (NMF) on the following thymocytes populations: common cortisone-resistant (CR); cortisone-resistant cells without macrophages (CR-M) and mature (PNP-) thymocytes was studied. It has been shown, that NMF shifts the catabolism of (8-(14) C) AMP towards hypoxanthine accumulation as well as stimulates the (2(-14) C) Thd incorporation in DNA of thymocyte populations to an increasing degree when comparing CR with PNA- cells. The action of NMF is not mediated by macrophages. It has been concluded that mature PNP- population is the target for NMF.

[The action of somatotropin and a nonpeptide mitogenic factor on thymocyte proliferative activity]. / Deistvie somatotropina i nepeptidnogo mitogennogo faktora na proliferativnuiu aktivnost' timotsitov.

Hydrocortisone-resistant thymocyte proliferation is stimulated by the nonpeptide mitogenic factor. In vivo incubation of hydrocortisone-resistant thymocytes in the presence of the nonpeptide mitogenic factor results in accumulation of extra- and intracellular hypoxanthine, originating from 8-14C-adenylic acid. Stimulation of in vitro incorporation of 2-14C-thymidine in the thymocyte DNA may be effected via the somatotropic hormone in case nonseparated thymocytes (but not hydrocortisone-resistant ones) are used. No hypoxanthine accumulation in somatotropin-stimulated nonseparated rat thymocytes was observed. 2-14C-thymidine incorporation in the hydrocortisone-resistant thymocyte DNA was enhanced by incubation of the cells in the presence of hypoxanthine in concentrations observed after thymocyte stimulation with nonpeptide mitogenic factor. The authors come to a conclusion that somatotropin and nonpeptide mitogenic factor stimulate the proliferation of two different thymocyte populations, that may be involved in the process of proliferation and regeneration of the thymus exposed to steroids.

[Role of thymocytes in the correlation between the thymus and hypophysis]. / Uchast tymotsytiv u vzaiemynakh mizh tymusom i gipofizom.

The influence of the thymus on the growth hormone (GH) level in the mouse hypophysis has been studied. It has been found, that syngeneic transfer of thymocytes of young mice into thymectomized mice causes on increase of the growth hormone level in the hypophysis. Administration of hydrocortisone simultaneously with transfer of thymocytes accelerated the GH level increase. The administration of only hydrocortisone into thymectomized mice does not lead to changes in the GH level. The increased GH level was observed when thymocytes were replaced by some structures shedding from thymocytes after their stimulation with short peptide thymic hormone. It is supposed that thymocytes can stimulate GH accumulation in the hypophysis.

[The determination of T-lymphocyte antigenic markers in the serum of patients with atopic dermatitis]. / Vyznachennia antigennykh determinant, prytamannykh T-limfotsytam, u syrovattsi krovi khvorykh na atopichnyi dermatyt.

The euglobulin fraction of serum of the patients with atopic dermatitis was studied using monoclonal antibodies OKT3, OKT8 and OKT10 in assay system including secondary 125J labeled anti-mouse IgG antibodies. It was shown that CD3, CD8 and CD38 T-cell marker antigens shed from the T-cell surface could be found in euglobulin fraction of serum patients. The patients with atopic dermatitis successfully treated with immunomodulator vilosen were selected and their serums obtained before and after treatment were investigated. The treatment resulted in the increase of CD8, CD3 determinants and a decrease of antigens determined by OKT10 antibodies (CD38). It is supposed that an increase of CD3 and CD8 determinants is caused by stimulation of T-lymphocyte proliferation and suppressor cell function by vilosen. Since CD38 marker is predominantly on the surface of immature and activated T-cells, which do not occur in circulating blood, it can be supposed that decrease of CD38 in the euglobulin fraction of serum reflects a shedding of these determinants from T-cells of thymus and peripheral lymphoid organs.

[Significance of adenylic acid catabolites for mouse thymus regeneration]. / Znachenna gipokantinu ta sechovoï kysloty dlia regeneratsii tymusu myshi.

The distribution of [8-14C]adenylic acid catabolites in mouse thymocytes in cortisone-resistant and total thymocyte population has been studied. The accumulation of labelled catabolites in a form of hypoxanthine was found preferentially in cortisone resistant thymocytes but not in total population. This accumulation considerably grows after incubation of cortisone resistant thymocytes with non-peptide mitogenic factor. The excretion of labelled hypoxanthine into medium was also observed. In order to investigate a significance of hypoxanthine accumulation cortisone resistant thymocytes were incubated in the presence of hypoxanthine range concentration and [14C]thymidine incorporation into thymocyte DNA was determined. It was found that [14C]thymidine incorporation into thymocyte DNA increases after incubation in presence of 0.5-5.0 micrograms of hypoxanthine or 0.0005-5.0 micrograms of uric acid. It has been concluded that stimulation of [14C]thymidine incorporation and thymocyte proliferation by non-peptide mitogenic factor is caused by hypoxanthine accumulation.

[Adenylic acid catabolism in thymocytes of the regenerating thymus in mice]. / Katabolizm adenilovoi kisloty v timotsitakh regeneriruiushchei v timotsitakh regeneriruiushchei vilochkovoi zhelezy myshi.

The T-cell non-peptide mitogenic factor isolated from the thymus stimulates thymus regeneration in mice previously treated with hydrocortisone. [8-14C]AMP catabolism in cortisone resistant thymocytes of mice has been investigated. Incorporation of radioactivity into hypoxanthine in cortisone resistant thymocytes is found to increase as compared with the total thymocyte population. Accumulation of labeled AMP catabolites in the form of hypoxanthine grows considerably after in vitro incubation of cortisone-resistant thymocytes with the non-peptide T-cell mitogenic factor. A large proportion of [8-14C]AMP catabolite radioactivity incorporated into cortisone-resistant thymocytes is excreted into the medium as hypoxanthine. It is supposed that hypoxanthine accumulation abrogates limitation of thymocyte DNA synthesis inhibited by relative excess of dGTP.

[Shedding of mouse thymocyte receptors for autologous erythrocytes under the influence of oligopeptide thymic factor]. / Otdalenie retseptorov timotsitov myshi k autologichnym éritrotsitam pod vliianiem oligopeptidnogo faktora timusa.

The supernatant obtained from the mouse thymocytes incubated with oligopeptide thymic factor can partially restore autorosette formation in heated at 45 degrees C and washed thymocytes which have lost the receptors for autologous erythrocytes. It is supposed that decreased level of autorosette formation after treatment of thymocytes with thymic factor is caused by shedding of receptors for autologous erythrocytes.

[Effect of hydrocortisone on the density-gradient distribution of autoreactive and 5'-nucleotidase-separating thymocytes]. / Vliianie gidrokortizona na raspredelenie v gradiente plotnosti autoreaktivnykh i otdeliaiushchikh 5'-nukleotidazu timotsitov.

Rat thymocytes forming rosettes with autologous erythrocytes, are separated by centrifugation in the ficoll-verografin density gradient into two unequal fractions. A minor part of rosette forming cells is found in the gradient layers with the density of 1.069 and 1.073, a major part in the layers with the density of 1.090 and 1.080. After the administration of hydrocortisone to rats (2.5 mg per 100 g of mass) the number of rosette forming cells increased but in the gradient light fraction (d = 1.069). At 37 degrees C this thymocyte fraction separates the greatest amount of protein with 5'-nucleotidase activity. Under hydrocortisone influence the number of cells in this fraction and the amount of separable protein per 10(6) cells as well as 5'-nucleotidase activity per 10(6) increased in this fraction only. It has been assumed that an increase in 5'-nucleotidase separated at 37 degrees C, is a more constant feature of cortisone resistant thymocytes than a low affinity to autologous erythrocytes which is usually regarded as a feature of mature thymocytes.

[Interaction of thymosin fraction 3 with opiate receptors]. / Vzaimodeistvie tret'ei fraktsii timozina s opiatnymi retseptorami.

Using the radioreceptor method thymosin fraction 3 was demonstrated to displace 3H-morphine and 3H-naloxone from opiate receptor of crude membrane fraction of the rat brain. The value of EC50 ratio in the presence and absence of 100 mM NaCl seems to indicate that thymosin contains one or several partial agonists of morphine. Furthermore, the peptide nature of these ligands is suggested on the basis of enzymatic treatment data. The possible role of opioid peptides in the realization of thymus endocrine functions is discussed.

The relationship between mouse thymocyte receptors for syngeneic and allogeneic erythrocytes and receptors for IgG.

Mouse thymocytes lose the affinity for syngeneic erythrocytes in the rosette formation test after heating in the isotonic medium for 1 h at 45 degrees. The thymocyte receptors for syngeneic erythrocytes appear in the medium after heating. The rosetting of heated and washed thymocytes is restored after incubation with the supernatant obtained from heating in medium thymocytes. The receptors for allogeneic erythrocytes were not separated from thymocytes under the same conditions of heating and washing. The receptors for syngeneic erythrocytes separated by heating can be adsorbed on the column with IgG-Sepharose conjugate and probably are connected with the receptors for Fc portion of IgG.

[Stimulation of antigen Thy-1 expression in mouse bone marrow cells by thymus extracts]. / Stimuliatsiia ékspressii antigena Thy-1 kletok kostnogo mozga myshei ékstraktami timusa.

The expression of antigen Thy-1 was studied in bone marrow cells of CBA line mice under the effect of thymus extracts. Extracts of the calf thymus--thymosine (fraction 5) and the preparation free of the Comsa factor were obtained by a combination of the Goldstein and Comsa extraction methods. The both extracts stimulate the expression of antigen Thy-1 in bone marrow cells. Incorporation of [14 C]sodium acetate into fragments containing antigen Thy-1 and absorbed by the column with anti-Thy-1-antibodies remains unchanged after stimulation. It is supposed that antigen Thy-1 ability to stimulate expression in bone marrow precursors of T-cells is not due to the synthesis of the antigen and is a property of one of the thymus factors with molecular mass of about 5000.

[Activity of cell-detached 5'-nucleotidase in thymocytes of various densities]. / Aktivnost' otdeliaemoi ot kletok 5'-nukleotidazy v timotsitakh razlichnoi plotnosti.

The rat thymocytes submitted to heating at 45 degrees C for 1 hr liberate plasma membrane fragments containing 5'-nucleotidase activity in the supernatant. The thymocytes were separated by ficoll density gradient centrifugation. High activity of 5'-nucleotidase per 10(6) cells was found in the supernatant of low density (1.069) subset of thymocytes. Thymocyte supernatant of rats treated with hydrocortisone demonstrated higher 5'-nucleotidase activity per 10(6) cells than in intact animals. This is due to an increase of the low density population of thymocytes in treated rats since the 5'-nucleotidase activity per 10(6) cells of the supernatant obtained from this density fraction is the same both in treated with hydrocortisone and intact rats. Hydrocortisone seems to induce a selection of the thymocytes with high 5'-nucleotidase activity.