The Influence of Myofibrils on the Proliferation and Differentiation of Myoblasts Cocultured with Macrophages.

We studied the effect of myofibrils on proliferation and differentiation of myoblasts cocultured with macrophages as well as the effect of incubation of macrophages with myofibrils on the expression by macrophages of the compounds that are cytokines for muscle cells. In the cocultures, macrophages stimulated the proliferation of myoblasts. Myofibrils greatly enhanced the stimulating effect of macrophages, whereas lipopolysaccharide (LPS) completely abolished it. The culture medium conditioned by macrophages activated the proliferation of myoblasts that were incubated with myofibrils but inhibited it when myoblasts were incubated with LPS. Possibly, myofibrils and their constituent proteins activate macrophages in an alternative pathway, enriching the population with M2-type macrophages.Z.

[Small interfering RNAs targeting human myostatin].

Ten human myostatin small interfering RNAs which sequence was found by two different software products were synthesized and tested for activity. It was found that three of them have pronounced biological activity and decrease myostatin mRNA level to 22-27% of control value. These small interfering RNAs stimulate human myoblast proliferation and decrease their differentiation reliably. The obtained small interfering RNAs can be used for development of new approaches for the treatment of sarcopenia and different myodystrophies.

Cytotoxic effects of macrophages and asbestos on transformed rat mesothelial cells.

Asbestos produced a cytotoxic effect on transformed cells of rat pleural mesothelium and on IAR2 epithelial cells and Rat1 fibroblasts transformed by ras oncogene, but not on normal cells of these strains under conditions of coculturing with peritoneal macrophages. Contact of mesothelioma cells, but not macrophages with asbestos was necessary and sufficient for attaining the cytotoxic effect. Macrophage-conditioned medium potentiated asbestos cytotoxicity for transformed mesothelial cells, but not for IARS-ras and Rat1-ras.

Cytokine secreted by rat macrophages and inhibiting proliferation of mesothelial cells.

Rat peritoneal macrophages and human peripheral blood monocytes secrete a protein with a molecular weight of 450 kDa, which specifically inhibits proliferation of cultured rat pleural mesothelial cells, but not fibroblasts and epitheliocytes. Protein secretion does not depend on the activation of macrophages. This cytokine is not a cobalamin-binding protein and has no arginase activity.

Secretion of immunoreactive corticotropin releasing factor and adrenocorticotropic hormone by T- and B-lymphocytes in response to cellular stress factors.

The ability of human lymphocytes and mouse splenocytes to secrete corticotropin-releasing factor (CRF) in response to hyperthermia, hyperosmolarity and hypoxia has been shown. Both human T- and B-lymphocytes appear to have this ability. E. coli lipopolysaccharide and concanavalin A can stimulate CRF secretion by B- and T-lymphocytes, respectively, whereas hydrocortisone inhibits the CRF secretion induced by any agent tested. Adrenocorticotropic hormone (ACTH) secretion in response to hyperthermia, hyperosmolarity and hypoxia was demonstrated also, and this secretion could be inhibited by anti-CRF antibodies and by hydrocortisone. We demonstrate that CRF could provide a necessary link between external stimuli such as cellular stress factors and ACTH secretion by immunocytes leading to corticosteroid production and, subsequently, to non-specific defence reaction of the organism. We also describe a model designed to explain the results obtained.

Monoclonal antibodies directed against two different corticotropin-releasing factor determinants.

Two hybridomas secreting monoclonal antibodies (mAbs) against human/rat corticotropin-releasing factor (CRF) have been produced by the cell fusion technique. Isotyping of the mAbs revealed that both belong to the IgG1 subclass. Human serum containing CRF-binding protein inhibits the binding protein inhibits the binding of CRF to both mAbs. Modification of lysine residue inhibits binding of the mAbs in a different manner. Affinity constants of binding with native and histidine-modified antigens have been determined by ELISA. The epitope specificity of the mAbs has been examined in competition experiments. No competition was detected, suggesting that the mAbs recognize different antigenic determinants. Two monoclonal antibodies can be employed in a two-site assay to measure CRF.

[The interaction of monoclonal antibodies to the structural proteins of the Vnukovo-32 vaccinal virus with other viruses of the rabies group]. / Vzaimodeistvie monoklonal'nykh antitel k strukturnym belkam vaktsinnogo virusa Vnukovo-32 s drugimi virusami gruppy beshenstva.

The interaction of 7 monoclonal antibodies (MCA) to the nucleocapsid complex and 3 MCA to protein G of the vaccine virus Vnukovo-32 with 33 and 27 members of the rabies virus group, respectively, was studied. The indirect immunofluorescence test showed 7 MCA to the nucleocapsid complex to recognize 4 antigenic determinants (AD). Two MCA recognized the AD common for all the viruses under study. Individual ecological variants may be detected using other MCA. Three MCA to protein G had marked virus-neutralizing activity. MCA 1C5 neutralized all the rabies viruses under study. The other two MCA differed in the number of viruses they could neutralize. The viruses under study were divided into 4 groups depending on their interactions with certain MCA in neutralization test.

[The isolation and characteristics of hybridomas producing monoclonal antibodies to the structural proteins of the Vnukovo-32 strain of the rabies virus]. / Poluchenie i kharakteristika gibridom, produtsiruiushchikh monoklonal'nye antitela k strukturnym belkam virusa beshenstva, shtamm Vnukovo-32.

A series of hybridomas secreting monoclonal antibodies (MCA) to glycoprotein and nucleocapsid proteins of rabies virus strain Vnukovo-32 was selected as a result of fusion of splenocytes from immune BALB/c mice with cells of myeloma line Sp2/OAq14, screening and cloning by limiting dilution methods in semi-liquid agar. Four hybridomas secreted MCA to glycoprotein in high titres (5.0 x 10(5)-2.2 x 10(6)) and had marked virus-neutralizing and therapeutic properties. Eight hybridomas produced MCA to the nucleocapsid complex: five hybridomas secreted MCA of the G class in high titres (2.4 x 10(5)-1.6 x 10(6)) and three hybridomas secreted MCA of the M class in low titres.

[The use of monoclonal antibodies for determining the transferrin content of the urine]. / Ispol'zovanie monoklonal'nykh antitel dlia opredeleniia soderzhaniia transferrina v moche.

The authors used monoclonal antibodies to human transferrin for the development of a high-sensitive test system for the assessment of transferrin levels in urine with enzyme immunoassay. The conditions of the immunoassay performance were optimized. The sensitivity of the test system enabled the authors to define the levels of transferrin up to 1 ng/ml. Tests for the detection of transferrin in patients with chronic pyelonephritis and chronic renal failure were performed. The designed test system permitted transferrin to be revealed in the urine of those patients who had negative results during a radial immunodiffusion. The authors demonstrated the possibility of using the developed monoclonal antibodies in laser nephelometry for the detection of blood and urinary transferrin levels.