Adipocytes and reticular cells of the bone marrow stroma in the human iliac bone

The results of the histological and electron microscopic investigation of adipose and reticular cells and their interconnections with blood cells are presented in the material of trephine biopsies of the iliac bone. A possibility for development of adipocytes from the adventitial reticular cells is demonstrated. Close contacts are revealed between pre-adipocytes and young hemopoietic cells. Two types of the reticular cells are characterized, they differ in their position, structural organization and interconnection with the young hemopoietic elements. The peculiarities revealed in the morphofunctional state of the microenvironmental structures demonstrate functional variegation of the stromal elements, and also attest an essential importance of intercellular contacts of the hemopoietic predecessors and the stromal cells in maintaining the hemopoietic function of the bone marrow.     

Effect of hydrocortisone on the properties of rat liver polyribosomes, metabolism, and template activity of polysomal poly-A-containing RNA

The effect of hydrocortisone on the amount of newly synthesized polyribosomal poly-A+-RNA and its translation activity and the distribution of polyribosomes in the induction dynamics according to their size were studied. It was shown that 3-5 hours after intraperitoneal injection of hydrocortisone the incorporation of labelled precursors into polyribosomal poly-A+-mRNA is increased, which is accompanied by rapid accumulation of mRNA in the polyribosomes. Under prolonged induction those parameters come down to the initial level. 4-7 hours after the injection of the hormone the relative amount of heavy polyribosomes (350-412S) in liver cells is increased. It was found that hydrocortisone significantly changes the specific translation activity of polysomal poly-A+-mRNA: it shows an increase 2-4 hours after the hormone injection and returns to the initial level 12 hours after the injection.     

Reconstruction of connective tissue from fibrin-based dermal equivalent transplanted to animals with experimental wounds

Wound healing in rats transplanted with dermal equivalent (DE) based on fibrin with dermal fibroblasts has been examined in this work. Histological studies of biopsy samples from dermis newly formed in the process of the model wound recovery in laboratory animals have shown the positive influence of DE on wound healing. It was found that the area of collagen fibers, number of precapillaries, capillaries and post-capillaries in granulation tissue were significantly increased in animals with transplanted fibrin-based DE compared to the rats of the control group indicating more intensive repair.     

Dynamics of the spatial structure of pulsed discharges in dense gases in point cathode−plane anode gaps and their erosion effect on the plane electrode surface

The dynamics of the spatial structure of the plasma of pulsed discharges in air and nitrogen in a nonuniform electric field and their erosion effect on the plane anode surface were studied experimentally. It is established that, at a nanosecond front of the voltage pulse, a diffuse discharge forms in the point cathode–plane anode gap due to the ionization wave propagating from the cathode. As the gap length decreases, the diffuse discharge transforms into a spark. A bright spot on the anode appears during the diffuse discharge, while the spark channel forms in the later discharge stage. The microstructure of autographs of anode spots and spark channels in discharges with durations of several nanoseconds is revealed. The autographs consist of up to 100 and more microcraters 5–100 μm in diameter. It is shown that, due to the short duration of the voltage pulse, a diffuse discharge can be implemented, several pulses of which do not produce appreciable erosion on the plane anode or the soot coating deposited on it.     

Cell cultivation on porous titanium implants with various structures

The paper presents data on the cultivation of human dermal fibroblasts and rabbit mesenchymal stromal cells on two types of porous titanium implants, i.e., those with irregular pores formed by pressed titanium particles and those with regular pores formed by the cohesion of one-size titanium particles inside the implant. The goal of this study was to determine what type of titanium implant porosity ensured its strongest interaction with cells. Cells were cultivated on implants for 7 days. During this period, they formed a confluent monolayer on the implant surface. Cells grown on titanium implants were monitored by scanning electron microscopy. Fibroblasts interaction with implants depended on the implant porosity structure. On implants with irregular pores cells were more spread. On implants with regular pores fibroblasts enveloped particles and were only occasionally bound with neighboring particles by small outgrowths. There was no tight interaction of particles inside the implant. In implants formed by pressed particles, cells grow not only on surface, but also in the depth of the implant. Thus, we suppose that a tighter interaction of cells with the titanium implant and, supposedly, tissues with the implant in the organism will take place in the variant when the implant structure is formed by pressed titanium particles, i.e., cellular interaction was observed inside the implant. In implants with irregular pores, cells grew both on the surface and in the depth. Thus, cells exhibited more adequate interactions with irregular pore titanium implants in vitro and hopefully the same interaction will be true in tissues after the implantation of the prosthesis into the organism.     

Zajdela hepatoma cells cultured in vitro

The goal of this work was to study cellular mechanisms of tumor progression and metastasizing. As a result of explantation of cells of rat Zajdela ascitic hepatoma, we obtained two transplantable cell cultures—monolayer (ZH-ad) and suspension (ZH-fl)—that differ in levels of cell differentiation and tumorigenicity. By using tumor-specific immune serum, we revealed tumor-associated antigens, synthesis of which is reduced or inhibited in ZH-ad cells, in outer membranes of the ZH-fl cells. Intraperitoneal injection into rat of 0.5–12 × 10⁶ ZH-fl cells leads to development of an ascitic tumor and death of 100% of animals, whereas, in the case of administration of ZH-ad cells, to achieve a tumorigenic effect, the minimal dose needs to be elevated to 20 × 10⁶ cells. Clonogenic analysis of the ZH-fl cells revealed three types of the formed clones—nonadhesive sphere colonies and two types of monolayer clones differing in proliferative potential, shape of colonies, and cell composition. Upon reaching a critical size, the spheres disintegrated, with separation of single cells and islands of different sizes, some of them being attached with monolayer formation. Three clonal cell lines were obtained: 1C as a result of expansion of a spherical clone and 4G and 10E from monolayer clones. We established that there is tumorigenicity of the 1C cell line, which, at a dose of 107 cells, led to the development of ascites and to the death of 50% of animals. The presented results indicate the existence in the ZH-fl cell population of tumor-initiating cells generating spherical clones—floating multicellular islets that, in culturing in the complete growth medium, are partly differentiated and are attached with monolayer formation.     

Immunomodulating effect of cyclophosphamide on cytotoxic activity of rats and mice splenocytes

This study examines the immunomodulating effect of cytostatic drug--cyclophosphamide (Cy)--on natural cytotoxic activity of rats and mice splenocytes. The cytotoxicity of the effector cells against the confluent monolayer cell lines of rat hepatoma Zajdela and HTC and mice hepatoma MH-22a was estimated by means the morphometric analysis. It was shown, that 48 h after single intraperitoneal injection of Cy produced a immunomodulating effect on the activity of splenocytes--suppressor action on cells of Zajdela hepatoma and immunopotentiating action on the target cells of HTC and MH-22a hepatomas. The possible mechanisms of immunopotentiating effect of Cy are discussed.