Experimental Model to Study the Role of Retinoblastoma Gene Product (pRb) for Determination of Adipocyte Differentiation.

Using stable constitutive expression of retinoblastoma gene product (pRb) in polypotent mesenchymal 10T1/2 cells we obtained stable cell lines hyperexpressing functionally active or inactive mutant pRb. The cells producing active exogenous pRb demonstrated high sensitivity to adipocyte differentiation inductors, whereas production of inactive form of the exogenous protein suppressed adipocyte differentiation. The obtained lines can serve as the experimental model for studying the role of pRb in determination of adipocyte differentiation.

[Oxygen consumption in the lungs and systemic circulation--different methods of measurement of one data or different data?].

The article deals with calculation of oxygen consumption in the lungs by means of breathing gas mixture analysis and in parallel--in the systemic circulation by reverse Fick method; 32 paired measurements were performed in 8 patients after cardiac surgery with cardiopulmonary bypass. The mean pulmonary oxygen consumption was higher than the same value calculated by the reverse Fick principle--148.4 +/- 39.9 ml x min(-1) x m(-2) and 120 +/- 35.1 ml x min(-1) x m(-2), respectively, the mean difference between two methods was 28.4 +/- 18.4 ml x min(-1) x m(-2). However, in two observations the interrelation was inversed. While analyzing physiological and methodological reasons for these differences, the authors concluded that, despite both methods can be used in monitoring systemic oxygen transport in the critically ill, they are not interchangeable, and valuable additional data could be derived from fast changes in lungs oxygen uptake.

[Epithelial intestine cells transdifferentiate into bladder urothelium in experiments in vivo].

The autoplastic surgery by intestine tissue has been used for reconstructive therapy of the urinary tract since the middle of the last century; however, cell mechanisms of the urothelium engraftment are still obscure. Intestine stem cells possess plasticity and presumably enable after the autoplastic surgery to transdifferentiate into mature cells of urinary tract. Using the preliminary developed in vivo model for evaluation of somatic cells transdifferentiation into urothelium, we have found that the epithelial intestine cells producing Gfp transdifferentiate into the cryoinjured bladder urothelium of the syngenetic C57BL mice. Gfp was detected in the bladder tissue of mice-recipients using reverted polymerase chain reaction, primary fluorescence and immunofluorescence, while colocalization of the Gfp and Her-4 revealing similar to urothelium staining pattern was demonstrated in a few urothelium cells by double immunohistochemical staining of the bladder tissue with specific antibodies. The results obtained suggest that epithelial intestine cells enable to transdifferentiate into bladder urothelium, however the transdifferentiation level is low and presumably can not provide full functional urothelium engraftment in the case of autoplastic bladder surgery by intestine tissue.

[Model in vivo to study the transdifferentiation of the somatic cell into urothelium].

Development of reconstructive therapy of the urinary tract using pluripotent and somatic stem cells, for example mesenchymal stem cell (MSCs), recently goes through the stage of experimental studies. These studies include investigation of the main functions of MSCs and urothelium lining from inside the organs of the urinary tract. An important role in the regulation of proliferation and differentiation of urothelium belongs to EGF and Wnt-beta-catenin signaling pathways which activity may be accessed by the level of Her-4 and Tcf3,4, accordingly. We found here that MSCs labeled by transgenic green fluorescence protein (GFP) did not produce in vitro Her-4 and Tcf3,4 but activated their production after transfer into cryoinjured bladder of the syngenic mouse. After MSCs transplantation, GFP was detected in the bladder by RT-PCR and was colocalized with Her-4 or Tcf3,4 in a few urothelium cells detected by immunohistichemical staining with specific antibodies. These results suggest that MSCs labeled by GFP may be used as a good model to study transdifferentiation of somatic cells into urothelium.

[Characteristic of tumors developed after transplantation of transgenic GFP-positive C57BL/6 mice bone-marrow mesenchymal stem cells to mdx mice muscle].

The purpose of the study was the morphological and histochemical characteristics of differentiation of tumors developed after transplantation of GFP-positive mesenchymal bone-marrow stem cells (MSC) of transgenic mice C57BL/6 into M. quadriceps femoris of mdx mice. The tumors occurred only after transplantation of MSCs of 43-45th passages and did not arise after transplantation of MSCs of the 15th passage. No tumors developed also after transplantation of MSCs of 43-45th passages into muscle of C57BL/6 mice. The average weight of tumors appeared in 4 mdx mice studied was 1.3 +/- 0.5 g. All four tumors were classified as mesenchymomas because they originated from mesenchymal stem cells. Most of the periphery of the tumors was classified as fibrosarcomas with mitotic index 0.9 +/- 0.1%. The central parts of tumors had areas with epithelial like morphology of cells. Such cells showed positive reactivity for alcyan blue staining at pH 2.5, which indicated chondrocyte nature of the cells. No mitosis was observed in epithelial like cells. In the tumors, there were also areas with bone trabeculae containing megacaryocytes and foci of myeloid and erythrocyte hematopoiesis. There were also areas with neuronal and glial cells, and accumulations of adipocytes. One of the tumors was classified as a round cells sarcoma. The observed types of tumor cell differentiation in vivo were in accordance with described in literature types of MSCs differentiation after induction in vitro with special inductors. The spectrum of in vivo differentiation of transgenic GFP-positive MSCs after transplantation to mdx mice was broader than the spectrum of in vivo differentiation of transfected or transformed in vitro adult MSCs after transplantation to immunodeficient mice and mdx mice.

[Spontaneous transformation and immortalization of mesenchymal stem cells in vitro].

Mesenchymal stem cells (MXC) possess plasticity and unlimited proliferative activity in vitro that makes them an attractive subject of the studies focused on searching new resources for regenerative medicine. The usage of MSC is effective for treatment of patients with degenerative and traumatic diseases of different tissues, however, biological basis of therapeutic efficacy of MSC are still obscure. We found that long term culture of MSC expressing transgenic green fluorescence protein (GFP) led to increase in their proliferative activity, decrease in adhesion, and loss of differentiation potential and production of the GFP. MSC at the first passages showed karyotipic features of transformation, that at the later passages were complicated with developing of tumorigenic abilities detected after transplantation into normal syngenic recipients. When explanted into cell culture conditions the cells of the tumor tissue originated from the MSC did not express GFP and were not inducible to differentiation, but in contrast to the parent cells showed decreased clonogenic and proliferative activities. We suggest that growth of MSC in vitro results in their spontaneous transformation at early passages. Immortalization making physiological basis for the unlimited proliferation of MSC in vitro may be a feature of MSC transformation but not an initial characteristic of the stem cells.

[Characterization of cultured murine mesenchymal stem cell line expressing GFP].

We have developed and characterized a murine mesenchymal stem cell line from the bone marrow of transgenic mouse C57BL ubiquitously expressing GFP. Immunostaining analysis revealed the presence of several markers typically found in fibroblasts such as smooth muscle cells actin in the form of stress fibrils and vimentin--the protein of intermediate filaments. These cells maintained capability to differentiate into adipocytes or osteoblasts under appropriate conditions. Karyotypic features include changes in the ploidy level between 2n and 8n and multiple chromosomal aberrations. After six passages 80% of the cell population was aneuploid with chromosomal numbers between 50 and 85 without well defined modal class. Differential G-staining of metaphase spreads showed variability in copy numbers of individual chromosomes and the presence of aberrations such as ectopic associations of non-homologous chromosomes. All analyzed cells contained unique dicentric marker chromosome and some of them also had numerous microchromosomes which might indicate gene amplification. These cells could be useful in the future work directed at the investigation of stem cells spontaneous oncogenic transformation in vivo and in vitro.

[Status of the glucocorticoid function of the adrenal glands in patients with juvenile rheumatoid arthritis]. / Sostoianie gliukokortikoidnoi funktsii nadpochechnikov u bol'nykh iuvenil'nym revmatoidnym artritom.

The authors studied the glucocorticoid function of the adrenals in 117 patients with juvenile rheumatoid arthritis (JRA) and in 37 children of the control group. Relation between the level of cortisol in the blood plasma and sex, age form and duration of the disease, indices of the clinical, laboratory and immunological activity, the nature of roentgenological changes in the joints and therapy was analysed. A decrease in the glucocorticoid function of the adrenal cortex correlated with the severity of the clinical forms and duration of the disease, being especially manifest in children of younger age. Hormonal therapy also causes significant and prolonged inhibition of the glucocorticoid function. The total contribution of the analysed sings of the disease being most significant for JRA from the clinical point of view did not influence much changes in cortisol concentration in the blood of the patients.

[Effect of acute hypoxia on the renin and erythropoietin activities of the blood serum in rats]. / Vliianie ostroi gipoksii na aktivnosti renina i éritropoétina v syvorotke krovi krys.

A comparative study of renin and erythropoietin content in the blood serum of rats with "endocrine" kidneys and changes in their activity following the action of specific erythropoietic stimulus (4-hour hypoxia) has been conducted. The presence of "endocrine" kidneys increased renin and erythropoietin activity in such animals. Acute hypoxia produced further increase in erythropoietin titre in the blood serum, with renin remaining at the same level. Possible differences in the mechanisms of renin and erythropoietin biogenesis in the kidneys are considered.

[Incretory changes in the pancreatic hormones in chronic pancreatitis]. / Izmenenie inkretsii nekotorykh gormonov podzheludochnoi zhelezy pri khronicheskom pankreatite.

Radioimmunoassay was employed to study blood content of insulin, C-peptide and glucagon in 78 patients with chronic pancreatitis. It was revealed that during exacerbation, there was an increase in the content of insulin and glucagon and, to a lesser degree, in that of C-peptide. During remissions, part of the patients showed insular deficiency which increased with disease standing. When pancreatitis lasted from 1 to 5 years or from 5 to 10 years, diabetes mellitus was recorded in 9.4% of the patients and in 16% of the patients, respectively.

[Effect of a hypoxic-hypercapnic gaseous medium and lowered temperature on the functional state of the rat hypothalamo-hypophyseal-thyroid system]. / Vliianie gipoksichesko-giperkapnicheskoi gazovoi sredy i snizhennoi temperatury na funktsional'noe sostoianie u krys sistemy gipotalamus-gipofiz-shchitovidnaia zheleza.

Radioimmunoassay and morphometry were used to study the time course of the function of the hypothalamus-pituitary-thyroid system in rats cooled under the conditions of the increasing hypoxia-hypercapnia. The changes in the function of this system exposed to combined factors were phasic in nature. The trend of the changes and functional activity of the test system depended, at individual times of cooling, on the pattern of environmental factors and reconstitution of the general body reactivity. It is suggested that the changes in the function of the hypothalamus-hypophysis-thyroid attest to the involvement of this part of the endocrine system in the body response to cooling and are thus one of the essential components in neuroendocrine regulation of the adaptive process responsible for the increased resistance of the animals to the exposure to extremal environmental factors.