Dual Character of Reactive Oxygen, Nitrogen, and Halogen Species: Endogenous Sources, Interconversions and Neutralization.

Oxidative stress resulting from accumulation of reactive oxygen, nitrogen, and halogen species (ROS, RNS, and RHS, respectively) causes the damage of cells and biomolecules. However, over the long evolutionary time, living organisms have developed the mechanisms for adaptation to oxidative stress conditions including the activity of the antioxidant system (AOS), which maintains low intracellular levels of RONS (ROS and RNS) and RHS. Moreover, living organisms have adapted to use low concentrations of these electrophiles for the regulation of cell functions through the reversible post-translational chemical modifications of redox-sensitive amino acid residues in intracellular effectors of signal transduction pathways (protein kinases and protein phosphatases), transcription factors, etc. An important fine-tuning mechanism that ensures involvement of RONS and RHS in the regulation of physiological processes is interconversion between different reactive species. This review focuses on the complex networks of interacting RONS and RHS types and their endogenous sources, such as NOX family of NADPH oxidases, complexes I and III of the mitochondrial electron transport chain, NO synthases, cytochrome P450-containing monooxygenase system, xanthine oxidoreductase, and myeloperoxidases. We highlight that kinetic parameters of reactions involving RONS and RHS determine the effects of these reactive species on cell functions. We also describe the functioning of enzymatic and non-enzymatic AOS components and the mechanisms of RONS and RHS scavenging under physiological conditions. We believe that analysis of interactions between RONS and relationships between different endogenous sources of these compounds will contribute to better understanding of their role in the maintenance of cell redox homeostasis as well as initiation and progression of diseases.

[A new antiviral drug Triazavirin: results of phase II clinical trial].

The results of the clinical trial testing the efficacy of a new anti-influenza drug Triazavirin are presented in this work. The data of the trial were gathered during the 2010 influenza season. The treatment with oral Triazavirin significantly reduced the duration of the main clinical symptoms of influenza (intoxication, fever, respiratory symptoms), decreased the incidence of the influenza-related complications and the use of symptomatic drugs. The re-isolation rate of the influenza A and B viruses was significantly lower in the patients who were using Triazavirin. The analysis of the clinical data showed that the optimal prescribed dosage was 250 mg 3 times a day.

[Methodological approaches to experimental investigation of drugs for the prophylaxis and treatment of prostate gland disorders].

New methodological approaches to preclinical study of the efficiency of potential prostatotropic drugs are suggested on the basis of original research and published data. An algorithm is proposed to investigate specific activity and safety of potential drugs for the prevention and treatment of prostate disorders.

[Methodological approaches to the experimental investigation of dermotropic drugs].

Methodological approaches to preclinical evaluation of the efficiency of potential dermotropic preparations are proposed on the basis of original investigations and an analysis of published data. At the first stage of the preclinical investigation of preparations for external application, it is necessary to estimate their acute toxicity, allergenic activity, and local irritation effect in addition to studying the specific activity.