Signaling events during macrophage activation with Betula pendula roth pectic polysaccharides.

We studied the effect of two pectic polysaccharides PS-B1-AG and PS-B2-RG that were contained in total polysaccharides extracted from Betula pendula leaves on NO production by mouse macrophages and the contribution of signaling molecules to macrophage activation by the test substances. Unlike the total sample, pectins produced a NO-stimulating effect on macrophages. The effect of PS-B2-RG (10 µg/ml) did not differ from the effect of LPS, while PS-B1-AG produced this effect only in a concentration of 20 µg/ml, which was probably due to differences in the chemical structure of the test substances. The studied pectin polysaccharides activated transcription factor NF-κB, kinases p38 and PI3, and cAMP as a negative regulator. These results indicate that Betula pendula polysaccharides are promising substances for creation of immunomodulating drugs.

In vitro effect of combined hybrid molecules from vitamin E analogues and betulinic acid on macrophage activity.

Macrophage activity was studied after treatment with hybrid molecules obtained by condensation of terpenic acid residues (betulinic and betulonic acids) and α-tocopherol analogues (α-tocopherol hemisuccinate and Trolox acid). As distinct from betulinic acid and α-tocopherol hemisuccinate, hybrid molecules did not exhibit cytotoxicity in relation to mouse peritoneal macrophages in the MTT test. Test substances inhibited the production of NO by mouse peritoneal macrophages. However, hybrid molecules had no effect on activity of macrophage arginase. Our results indicate that new molecules have anti-inflammatory activity. It can be hypothesized that these substances have immunomodulatory properties.

Thyroid mass in children and adolescents living in the most exposed areas to Chernobyl fallout in Belarus.

This paper aims to determine the thyroid volumes in children and teenagers living in Gomel and Mogilev Oblasts, which are the areas of Belarus that were most affected by the Chernobyl accident. Results of thyroid volume measurements performed in 1991-1996 by the Sasakawa Memorial Health Foundation were used to evaluate the variation by age of the thyroid volumes for girls and boys aged from 5 to 16 y. Thyroid volumes for age groups without measurements were also estimated. For a given age and gender, the differences between children from Gomel and Mogilev Oblasts do not exceed 12 %, which is relatively small when the variability of individual values is considered. For children of a given age, the individual values show a variability characterised by geometric standard deviation (GSD) of 1.25-1.4. Values of thyroid mass that were derived from the measured thyroid volumes are being used within the framework of the on-going Belarusian-American cohort study of thyroid cancer and other thyroid diseases after the Chernobyl accident to estimate with more accuracy the thyroid doses that were received by the cohort members.

Water-soluble polysaccharide obtained from Acorus calamus L. classically activates macrophages and stimulates Th1 response.

A pectic polysaccharide was isolated from the rhizomes of Acorus calamus L. The main component of its carbohydrate chain was represented by residues of D-galacturonic acid (>85%). In addition, this polysaccharide contained residues of galactose, arabinose, xylose and rhamnose (<10%). Structural analysis of pectic polysaccharide from A.calamus L. with NMR spectroscopy indicated that it contains the regions of a linear 1,4-alpha-D-galactopyranosyluronan, which represents a major component of the macromolecule. A considerable amount of galacturonic acid residues was not methoxylated. We demonstrate here that the pectic polysaccharide from A. calamus L. in low concentrations was able to stimulate in vitro IL-12 and nitric oxide production by murine macrophages. It also induced TNF-alpha secretion by human peripheral blood mononuclear cells, reduced arginase activity but did not affect IL-10 secretion by murine macrophages or human peripheral blood mononuclear cells. The IL-12 and NO-stimulating effects on murine macrophages were similar to that of LPS. In addition, the polysaccharide promoted in vivo Th1 immune response in mice which were immunized with sheep red blood cells (DTH and quantity of plaque-forming cells) and down regulated serum level of IgG1 and IgE during Th2-depend immune response induced by ovalbumin. The PS increased Th1-induced edema and suppressed Th2-induced paw swelling in adoptive systems. Our results suggest that the pectic polysaccharide from A. calamus L. represents a promising immunomodulating agent that stimulates M1-polarized macrophages and promotes Th1-oriented adaptive immune response. We propose that this polysaccharide could be potentially applied for treatment of infectious, oncological diseases or for immunoglobulin-E-mediated disorders.

Information processing using dynamical chaos: neural networks implementation.

In this work, we study information processing applications of complex dynamics and chaos in neural networks. We discuss mathematical models based on piecewise-linear maps which enable us to realize the basic functions of information processing using complex dynamics and chaos. Realizations of these models using recurrent neural-like systems are presented.