Oleic acid is a key cytotoxic component of HAMLET-like complexes

HAMLET is a complex of α-lactalbumin (α-LA) with oleic acid (OA) that selectively kills tumor cells and Streptococcus pneumoniae. To assess the contribution of the proteinaceous component to cytotoxicity of HAMLET, OA complexes with proteins structurally and functionally distinct from α-LA were prepared. Similar to HAMLET, the OA complexes with bovine β-lactoglobulin (bLG) and pike parvalbumin (pPA) (bLG-OA-45 and pPA-OA-45, respectively) induced S. pneumoniae D39 cell death. The activation mechanisms of S. pneumoniae death for these complexes were analogous to those for HAMLET, and the cytotoxicity of the complexes increased with OA content in the preparations. The half-maximal inhibitory concentration for HEp-2 cells linearly decreased with rise in OA content in the preparations, and OA concentration in the preparations causing HEp-2 cell death was close to the cytotoxicity of OA alone. Hence, the cytotoxic action of these complexes against HEp-2 cells is induced mostly by OA. Thermal stabilization of bLG upon association with OA implies that cytotoxicity of bLG-OA-45 complex cannot be ascribed to molten globule-like conformation of the protein component. Overall, the proteinaceous component of HAMLET-like complexes studied is not a prerequisite for their activity; the cytotoxicity of these complexes is mostly due to the action of OA.     

Immunoglobulins and staphylococcal antitoxin in the sera of patients subjected to surgery for acute appendicitis]

The content of staphylococcus antitoxin and IgA, IgG and IgM was studied in the sera of 200 patients operated on for various forms of acute appendicitis. 147 patients were subjected to express-immunization with a crude staphylococcus toxoid. It was revealed that the IgA, IgG and IgM level was much lower in the operated on patients than in healthy persons. Express immunization with the toxoid led to a marked increase in the level of staphylococcus antitoxin and also of the IgA, IgG, IgM in the sera of the vaccinated persons. There was no distinct association between the immunoglobulin content in the sera of the patients and the appearance in them of postoperative complications of staphylococcus etiology; it is not excluded, however, that an intensified IgM synthesis could play a certain role in the protection of the macroorganism from staphylococcus infection. A moderate, but statistically significant correlation between the titre of the staphylococcus antitoxin in the sera of the patients and the content of the IgM and IgA in them was revealed.     

Cytotoxic effect of dihydroquercetin and its derivatives in liposomal form and in the form of fat nanoscale emulsions

We studied cytotoxic effects of dihydroquercetin (DHQ) and its derivatives, penta-O-acetylsalicylate dihydroquercetin (PAS DHQ), penta-O-acetate dihydroquercetin (PA DHQ), and penta-O-benzoate dihydroquercetin (PB DHQ), in aqueous solutions, liposomal form, and in the form of fat emulsions, on cultured tumor cells HL-60 and HEp-2. Solubility of the DHQ derivatives in aqueous solutions was much lower than that of DHQ. Modification of DHQ either did not alter its toxicity (PAS DHQ) or significantly reduced the cytotoxic effect of DHQ on tumor cells (PA DHQ, PB DHQ). DHQ and its derivative PAS DHQ were more toxic when dissolved in an aqueous solution than in the form of liposomes. Cytotoxic effect of DHQ applied in the form of fat emulsion was significantly higher than in the liposomal form and was close to the activity of DHQ in a solution. These results can be implicated for the development of new anticancer drugs based on liposomal and fat emulsions.     

Aggregation of Nanosized Hydroxyapatite Particles and Inhibition of Cell Adhesion on this Bio-Active Material as Key Factors that Limit its Biointegration

Biophysics - Abstract—Different synthetic calcium phosphate compounds are used as osteoplastic materials for filling of bone defects during surgical reconstruction of bone. Synthetic...     

Patterns in the antigen-nonspecific modulation of the B-cell activity in mice under the influence of a purified staphylococcal anatoxin

Purified staphylococcal toxoid (PST) has been shown to be an antigen-nonspecific immunomodulator, capable of inducing changes in the immune response of B-cells to unrelated antigens, such as sheep red blood cells (SRBC), in a wide range of doses (from 15 to 0.15 binding units per mouse). The manifestation of the immunomodulating effect depends on the conditions of the experiment: the doses of PST and SRBC, the age of mice, the sequence of the injections of the antigens and the intervals between the injections. The simultaneous injection of PST and SRBC induces, as a rule, an increase in immune response to the test antigen, while their separate injection induces mainly immunosuppression.     

Intracellular pH and the proliferation of BHK-21 cells

Data are presented on the dynamics of intracellular pH (pHi) in the course of growth of BHK-21 cells in suspension and on solid substrate. Cell proliferation in suspension in the presence of bicarbonate occurs at a mean value of pHi 6.76 +/- 0.02, which is only by 0.06 higher than that for resting cells. Adhesion of cells to the substrate cause a short (12 to 24 h) increase in pHi to 7.0-7.2, then proliferation of spread cells continued at pHi 6.8 +/- 0.03. Thus, for proliferation of substrate-independent BHK-21 cells to occur, there is no need for an additional alkalization of the cytoplasm at the expense of cell adhesion to a solid substrate, so the cells grow at low pHi values and at weak alkalization provided by adding serum. Data are presented that the Cl- and HCO(3-)-transport into the cell as well as Na+/H+ exchange are involved in pHi regulation. The decrease in pHi and inhibition of cell proliferation were observed in the presence of amiloride in bicarbonate-containing medium.     

Correction of immune response using purified staphylococcal toxoid and likopid in the secondary immunodeficiency induced by Coxsackie virus B3

The action of immunomodulators, purified staphylococcal toxoid (PST) and lycopid, on secondary immunodeficiency state developing during infection caused by Coxsackie virus B3 was studied. This defect was manifested by delayed hypersensitivity to sheep red blood cells (SRBC) and the suppression of neutralizing antibodies to poliomyelitis virus. Depending on the scheme of the experiment, PST normalized the defects of immune response to SRBC or poliovirus, increased suppression or showed no activity. Lycopid corrected the defects of humoral response to SRBC. The combination of PST and lycopid was found to produce no increase of suppression. The suggestion was made on the expediency of combination of two (and probably more) immunomodulators for increasing the efficiency of correction of secondary immunodeficiency.     

Migration of fibroblasts into heart valve leaflet tissue in vitro

Heart valve allografts are widely used for surgical treatment of the heart. In recent years a new field of research has emerged dealing with allograft modification by cells of recipient by means of tissue engineering. This method involves culturing fibroblasts and endothelial cells, using recipient tissue, followed by introduction of the fibroblasts into tissues of allograft and coating its surface by the endothelial cells. This modification is expected to ensure the structural maintenance of implanted tissues and to reduce its thrombogenecity. This procedure may promote the allograft adhering to the recipient tissues, thus prolonging the terms of the valve normal functioning after implantations. For this purpose, methods of luminescent microscopy are suggested using double staining of tissue with fluorescent dyes Hoechst 33,342 and ethidium bromide, or with fluorescein diacetate and ethidium bromide. Experimental results are presented indicative of fibroblast migration from the surface to the human heart valve leaflets.