[PECULIARITIES OF INTERACTION IN THE "PARASITE-HOST" SYSTEM IN HIV-INFECTED PATIENTS WITH TOXOPLASMOSIS: LITERATURE AND CLINICAL CASE REVIEW].

The article presents a review of current literature data on the development of opportunistic toxoplasmosis in patients suffering from HIV infection and a clinical case of an immunocompromised patient with toxoplasmosis. Current information concerning the incidence of toxoplasmosis in Russia and other countries are presented. Special attention is paid to the Toxoplasma gondii interactions with the host cell in HIV-infected people. The mechanism of parasite penetration into the host cell and subsequent modifications that the parasite makes with the occupied cell are analyzed in detail. The significance of the chosen topic is illustrated by the description of a clinical case of toxoplasmosis in an HIV-infected patient. The authors hope that the article will help to attract attention of the professional community to the problem of opportunistic infections in HIV/AIDS carriers, and in particular to the mechanisms of the "parasite-host" interactions in patients with toxoplasmosis.

[SEVERE FORMS OF TROPICAL MALARIA: MOLECULAR GENETIC FEATURES OF THE COURSE OF THE INFECTION (REVIEW)].

The article overviews some issues of the severe course of tropical malaria. In addition to the analysis of the ongoing situation with malaria in Russia, a general clinical picture of the severe course of tropical malaria is discussed. The main part of the overview includes a detailed analysis of current data on the molecular genetic aspects of the erythrocytes' adhesion in the case of tropical malaria. The main elements involved in the process of binding red blood cells and, as a result, in the process of their adhesion to other cells of the human body were considered in detail. Data were studied and summarized not only on protein interactions between an infected red cell and its cellular environment, but also on the genetic characteristics of the parasite leading to similar molecular-biological processes. In addition to the study of protein PfEMP1 role which is nowadays well-considered in the literature, the most up-to-date but less reported data on erythrocyte adhesion proteins STEVOR and RIFIN were also included. The team of authors hopes that this publication will help to get a deeper insight into the problem of erythrocyte adhesion in the course of complicated malaria infection forms and to summarize some of the available data on this issue.

[THE SIGNIFICANCE OF THE SYSTEM APPROACH IN THE STUDY OF THE GENERAL ADAPTATION SYNDROME' REACTIONS].

The article discusses the problems of the process of environmental adaptations appearance which are based on the general principles of functional systems' constitution. The value of the theory of functional systems development as the basis for physiological cybernetics (P. Anokhin, 1935) is also given. A general adaptation syndrome ("a stress - syndrome") that was discovered by H. Selye is chosen as an example to explain the development of the stages of the functional system of the stress, the sequence and value of ongoing physiological reactions and negative feedback interactions. The stress - syndrome reactions are the nonspecific response of a particular organism to various factors: emotional shock, trauma, infections, surgery, burns etc. The article also paid attention to the reasons and conditions for the failure of adaptations' emergence and the transformation of adaptive reactions into pathological ones. The key role of stress syndrome reactions as the main or auxiliary etiological factor in the development of coronary heart disease, hypertension, atherosclerosis, lesions of the stomach and duodenum, immunodeficiencies, etc. is indicated. To be effective in interactions with the environment, organisms have developed different mechanisms which are not only activating but also suppressing the excessive activity of the functional stress system that damages the organs. Therefore, the article considers the significance of negative feedback adaptations that act as stress - initiating and stress - limiting mechanisms.

[COMPARISON OF THE EFFECTIVENESS OF DRUGS FOR THE TREATMENT OF CUTANEOUS LEISHMANIASIS IN VITRO].

In this study, we studied the activity of three antibacterial drugs: Cefotaxime (Claforan, France), Ceftriaxone (Russia) and Doxycycline (Russia). The control group is a pentavalent antimony drug - Glucantim (France), which has been the "gold standard" for a long time in the treatment of any form of leishmaniasis. During the experiments, the leading positions of doxycycline and ceftriaxone established in vitro. Minimal doses of both drugs lead to absolute suppression of the mobility of the pathogen L. major. Increasing the therapeutic dose of drugs is not justified. Comparison of these drugs with the gold standard of therapy with meglumine antimonate (glucantim) showed their superiority in all indicators.

[GENETIC ASPECTS OF RESISTANCE TO MALARIA (REVIEW)].

Malaria is one of the most important and common infectious diseases in the world. The world health organization estimates 225 million malaria cases worldwide. Malaria is one of the strongest selective factors affecting the human genotype. The greatest pressure of malaria pathogens had on the inhabitants of the tropical belt, in which invasion was the main factor of genetic selection. As a result, there were genetic diseases such as sickle cell anemia, thalassemia, glucose-6-phosphate dehydrogenase deficiency and others. An important role in the pathogenesis of malaria is the stage of penetration of the parasite of malarial Plasmodium into the erythrocyte. Changes in the structure of surface antigens of red blood cells may contribute to or reduce the effectiveness of invasion. Genetic polymorphism associated with the pathogenesis and characteristics of the malaria clinic is also important in the development of malaria resistance. Understanding the genetic changes associated with red blood cell disorders and pathogenesis can provide insights into the development of new strategies for malaria treatment and prevention.

Changed course of cytotoxic reaction as a result of modification of target cell membrane.

We studied the sensitivity of K-562 erythromyeloblasts cultured for a long time in a nutrient media of common composition (control) or medium modified by proline-rich hexapeptide, to cytolysis mediated by natural killers. On day 2 of culturing the cytotoxicity of human natural killers towards targets maintained in the modified medium was almost 2-fold higher than in the control. By day 30 this difference was retained at the effector:target ratio of 50:1 and 12:1. By day 90 of the experiment activity of natural killers towards K-562 cells cultured in modified medium was lower than in the control. The results are discussed in the context of hydration of the target cell surface structures at the expense of bound water brought by proline-rich open type sequences into the distal regions of extracellular sites of adhesion receptors and target determinants recognized by natural killers.