The biological action of low-level radiation

On the basis of their own data and the literature the authors have analyzed the mechanism of biological action of low-level radiation on cells. In studying the harmful effect of gamma-radiation (10-40 cGy) on HeLa cells it was shown that damages occurred in 12 postirradiation generations. Analysis of cell distribution within the colonies has demonstrated that the share of colonies with low cell content and the number of giant cell increase. These data indicate that low-level radiation causes reproductive cell death that can occur not immediately but in later generations.     

On the mechanism of the biological action of some nitrophenols

The pH dependence of the germinative capacity inhibition by 14 nitrophenol derivatives was estimated on the conidia ofNeurospora sitophila. The improtance of maintaining accurate pH during biological tests, particularly with derivatives possessing a low pK value is emphasized. The McGowan relationship cannot be applied to the group of substances investigated here. No relationship could be established between the biological activity and lipid solubility. The effect of acidity of the medium and pK of fungicides on the course of absorption of phenols byNeurospora sitophila spores was studied.     

Intratumor heterogeneity: Nature and biological significance

Intratumor heterogeneity inherent in the majority of human cancers is a major obstacle for a highly efficient diagnosis and successful prognosis and treatment of these diseases. Being a result of clonal diversity within the same tumor, intratumor heterogeneity can be manifested in variability of genetic and epigenetic status, gene and protein expression, morphological structure, and other features of the tumor. It is most likely that the appearance of this diversity is a source for the adaptation of the tumor to changes in microenvironmental conditions and/or a tool for changing its malignant potential. In any case, both processes result in the appearance of cell clones with different undetermined sets of hallmarks. In this review, we describe the heterogeneity of molecular disorders in various human tumors and consider modern viewpoints of its development including genetic and non-genetic factors of heterogeneity origin and the role of cancer stem cells and clonal evolution. We also systematize data on the contribution of tumor diversity to progression of various tumors and the efficiency of their treatment. The main problems are indicated in the diagnosis and therapy of malignant tumors caused by intratumor heterogeneity and possible pathways for their solution. Moreover, we also suggest the key goals whose achievement promises to minimize the problem of intratumor heterogeneity and to identify new prognostic, predictive, and target markers for adequate and effective treatment of cancer.     

New data on the biological action of normal immunoglobulins

Experiments on 2,520 CBA mice (CBA X X C57BL) F1 nice have shown that the injection of homologous serum immunoglobulins (obtained from intact and blood-stimulated animals), made 2 hours after gamma irradiation from a 60Co source, prevents the development of intestinal dysbacteriosis and endogenous infection. The injection of mouse and human immunoglobulins to nonirradiated mice improved their resistance to experimental infection with Escherichia coli live culture, increased the expression of receptors to the Fc-fragments of IgG in peritoneal macrophages and enhanced the physical working capacity of the animals. The preparations containing normal antitissular antibodies have proved to be particularly effective. In mice, rabbits and dogs the preparations under test have produced no changes in the general state of the animals, no local reactions and no disturbances in the cardiovascular activity.     

Mechanism of action of biological antioxidants.

More and more diseases have been proposed to have a radical or oxidant involvement. Although in most cases we do not know if this involvement is a cause or a result of the disease process, it is still valuable to learn about those compounds or enzymes that might block, inhibit, or prevent radical-initiated reactions. Therefore, it becomes increasingly important to understand which compounds can function as antioxidants, where they are located in the body, and what their mechanism of action might be. As we increase our knowledge in these areas, we will have a better opportunity to propose interventions that might suppress or even reverse some of the ravages of oxidant-based diseases in humans.     

The biological action of Yersinia pseudotuberculosis endotoxin

Experimental studies on guinea pigs have shown that Y. pseudotuberculosis lipopolysaccharide is capable of inducing endotoxinemia accompanied by the development of the thrombohemorrhagic syndrome. In cases of pseudotuberculosis the importance of the increased synthesis of prostaglandins and cyclic nucleotides with the prevalence of PGF2 alpha and cGMP in the genesis of toxico-allergic manifestations of pathologic processes has been established. The pathomorphological picture of pseudotuberculosis endotoxinemia is characterized by sludge, the vascular thrombosis of the microcirculatory bed, diapedetic hemorrhages, delymphatization of the immunogenetic organs. The moderately pronounced action of indomethacin, a prostaglandin inhibitor, on the manifestations of pseudotuberculosis endotoxinemia has been revealed.     

Delayed biological effect of electromagnetic fields action

The real possibility of the development of remote effects in people after longterm EMF-exposure was presented in the world scientific literature. Many authors decided that there is connection between long-term EMF-exposure and development of the breast cancer, brain tumours, leukaemia and neurodegenerative diseases (Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis). The analysis of up-to-date publications leads us to the conclusion that this problem is actual and further researches of conditions provoking development of last-term effects are required.