Asymmetric DNA methylation between sister chromatids of metaphase chromosomes in mouse embryos upon bisphenol A action.

Earlier we showed that asymmetric methylation of sister chromatids (AMSC) was a specific characteristic of differentiation potency, and supposed that AMSC could be a useful marker of environmental impact connected with differentiation and/or dedifferentiation. Here we investigated the level of AMSC in chromosomes and the nuclei methylation in mouse preimplantation and postimplantation embryos, in comparison with the undifferentiated cells of mouse embryonal carcinoma cell line F9, and human differentiated HEK293 cells upon BPA influence. We found that exposure of mouse preimplantation embryos to BPA caused a significant decrease in the level of AMSC in chromosomes and the nuclei methylation. The BPA exposure of potentially differentiating F9 cells had no any influence on DNA methylation in nuclei but significantly decreased the number of AMSC. The level of DNA methylation and AMSC in HEK293 cells were not also changed. These data indicate that BPA exerts significant influence on differentiating and potentially differentiable cells. The most sensitive BPA targets are preimplantation embryos and stem cells.

[THE INFLUENCE OF THE PREPARATION PRETREATMENT ON IN SITU DETECTION OF 5-METHYLCYTOSINE IN METAPHASE CHROMOSOMES AND IN INTERPHASE NUCLEI].

Qualitative and quantitate analysis of DNA methylation in situ at the level of cells, chromosomes and chromosomal domains is extremely important for the diagnosis and treatment of various diseases, the study of ageing and the consequences of environmental impacts. An important question arises, whether the revealed in situ methylation pattern reflects DNA methylation per se and (or) availability of the DNA for antibodies, which in turn depends on the peculiarities of chromatin structure and chromosome condensation. These events can lead to an incorrect evaluation of the actual pattern of DNA methylation. To avoid this shortcoming as far as possible, we have modified the most widely used method of revealing 5-methylcytosine in situ with monoclonal antibodies. Here we have shown that the detection of DNA methylation staining of chromosomes including C-heterochromatin, chromosomal arms and sister chromatids is drastically dependent on pretreatment of chromosomal preparations for immunocytochemical study using fluorescent antibodies. Using undifferentiated stem cells of mouse embryonal carcinoma line F9, it has been found that change in preparations storage results in a sharp fluorescence decrease up to complete disappearance of the signal in centromeric heterochromatin. With the help of the method described in the work, we have first revealed the asymmetry of sister chromatids methylation in metaphase chromosomes of F9 cell and lymphocytes of human periphery blood. This may lead to asymmetry of transcriptional signature of daughter cells after division. The proposed here modification of 5-methylcytosine detection in situ provides a more complete characterization of methylation of chromosomes and chromosomal domains, compared to previously published methods.

[Molecular and cellular aspects of dioxin toxicity].

BACKGROUND: Using methods of molecular toxicology to study dioxin intoxication consequences the contribution was accessed of pathologic alterations induced and manifested by specific biomarkers and ecogenetic effects among Vietnamese population living on contaminated territories. The causes of variability in individual sensitivity to toxic activity were also evaluated. MATERIALS AND METHODS: Individual biomedical indices were compared between those living in contaminated with dioxins (n = 8142) and control (n = 4421) regions. Dioxin concentrations were measured by high resolution chromato-mass spectrometry (84 samples). The characteristics of cytochrome P-450 system state (94 persons) and cytogenetic parameters (368 persons, 331 450 cells) reflected the molecular and genetic effects. Variable sensitivity to dioxins was demonstrated by associations of genetic polymorphism (CYP1A1, GSTM1, GSTT1, n = 195) and congenital morphogenetic variants among children (n = 1734). RESULTS: Numerous consequences were demonstrated among the exposed individuals: noticeable absobtion of dioxins from environmental objects; direct effects of P-450 system's induction; systemic alterations in nucleus and genetic stability; changes in cellular generation's rate. The associations were revealed of genetic polymorphism in xenobiotic biotransformation/detoxification system and the peculiarities of development and morphogenesis among exposed children. CONCLUSION: Characteristics of population chronicle intoxication with dioxins permitted to describe its numerous preclinical and clinical manifestations, to show the key elements in pathogenesis of revealed alterations. Future investigations are to create the groundwork for developing a method for prevention of dioxin pathology induction and realization based on revealing preclinical signs and effects of intoxication.

[Clinical toxicology of the Academy: yesterday, today and tomorrow].

National toxicology school of the Kirov Military Medical Academy, demonstrates the unity of clinical and experimental approaches related to one purpose throughout its history--saving human life and health from exposure to toxic substances of chemical nature. For more than three centuries the russian science of toxicology has been steadily developing, often ahead of the world science. It helped to create the means of protection and develop methods of treatment for chemical lesions. Currently, toxicology departments of military field therapy and military toxicology and medical protection are actively involved in the current study of military medicine, restructuring policy to provide toxicological aid in the Armed Forces, the development and introduction of Innovative methods of diagnosis and treatment of victims of toxicological etiology.

[Features of hemocomponental therapy in oncological patients].

The authors present an analysis of specific features of transfusions of erythrocyte containing media in oncological patients. Special attention was given to necessary selection of donor erythrocytes in performing operations with massive intraoperative blood loss. It considerably contributes to a decreased number of posttransfusional reactions and complications. For the recent five years transfusions of erythrocyte containing media to more than 15 thousand patients with surgical treatment were analyzed. Among them the individual selection of donor blood was fulfilled in 2047 cases. Compatible erythrocytes could not be selected in five cases only. In these patients infusions of Perftoran were used as an oxygen carrier both during operation and at the postoperative period.

[The congenital morphogenetic variants and genetic polymorphism of the system of xenobiotic detoxication in children living in dioxin-contaminated regions of South Vietnam].

The presence of dioxins and dioxin-containing ecotoxicants (DCE) in human environment leads to multi-level homeostasis disbalance and, eventually, dioxin pathology (DP) develops. This was demonstrated for the adult population of South Vietnam (1), who had suffered from the use of military chlorphenoxiherbicides to which dioxins had been added. The subjects of this study were children who belonged to the second generation of the inhabitants of DCE-polluted South Vietnam areas. In this sample, the frequency of malformations depending on two factors, genes GSTMI, GSTT1, CYP1A1 genotypes, and DCE exposure, were estimated. The study demonstrates that an increased level of congenital morphogenetic variants per one child is associated with the presence of DCE in the environment, as well as the fact that this parameter is influenced by genotypes of xenobiotic detoxication genes.

[New blood substitutes of polyfunctional action]. / Novye krovezameniteli polifunktsional'nogo deistviia.

The paper deals with two categories of new oxygen-carrying blood substitute solutions (OCBSS), based on a modified hemoglobin (MG) and perfluor-organic carbon emulsion (PCE), and with crystalloid and colloid blood substitutes of the antihypoxic action containing the Crebs' substrate (sodium fumarat). Described are the results of clinical use of Russian OCBSS based on MG (Gelenpol) and on PCE (Perftoran) in 151 patients with hemorrhagic shock and intraoperative blood loss. Both drugs are allowed for medical application in Russia. Gelenpol was administered at 1 to 6 units, perftoran--at 10-15 ml/kg. An improved oxygen status as well as normalization of hemodynamics, microcirculation, rheology, and of blood acid-base balance (ABB) were registered. Gelenpol had a hematosis-stimulating action. The combined use of both drugs or one of them alone in surgery is under discussion. The OCBSS efficiency can be enhanced when they are used jointly with the first Russian infusion antihypoxants containing sodium furmarat, i.e. Mufasol and Polyoxyfumarin. Both of them were shown to normalize the oxidation in tissues, to recover the mitochondrial metabolism in the liver and myocardium and to improve the blood ABB when used in hypovolemic and hypoxic conditions of different etiologies, in substituting for intraoperative blood losses (gastrointestinal hemorrhages), in polytrauma and destructive cholecystitis as well as in preoperative preparations of patients with diffuse peritonitis. The OCBSS preparations and antihypoxants are undoubtedly drugs of choice in emergency infusion-transfusion therapy and in cases of multiple victims from accidents.

[Use of an artificial carrier of oxygen on the base of modified hemoglobin in patients with gastroduodenal hemorrhage]. / Primenenie iskusstvennogo perenoschika kisloroda na osnove modifitsirovannogo gemoglobina u bol'nykh s gastroduodenal'nymi krovotecheniiami.

Infusions of Helenpole used in 23 patients allowed for a short time to stabilize hemodynamics and to considerably improve the gas-transporting function of blood. The best curative effect in patients with hemorrhagic shock was obtained by means of intravenous jet infusions of the medicine, after stabilization of the hemodynamic indices with the help of an intravenous dropper (80-90 drops/min). The dose of the 1% solution of the medicine was 25-30 ml/kg of the patient's body weight.

[Current views on molecular structure of benzodiazepine receptors]. / Sovremennye predstavleniia o molekuliarnoi strukture benzodiazepinovykh retseptorov.

It is generally accepted that gamma-aminobutyric acid (GABA) is the most important inhibitory transmitter. It interacts with specific receptors. In the central nervous system of the vertebrates there are three types of GABA receptors: GABAA, GABAB, and GABAC receptors. Channel gating at GABAA receptors allosterically is modulated by a wide of neuroactive compounds, including benzodiazepine ligands. The structural and functional bases for the heterogeneity of benzodiazepine receptors are discussed. Investigations of the functional properties of GABAA and benzodiazepine receptors may contribute to progress in neurobiology, neuropathology, neurochemistry, toxicology, and pharmacology.

[The potentials of molecular genetic diagnosis in military medicine (a review of the literature)]. / Vozmozhnosti molekuliarno-geneticheskoi diagnostiki v voennoi meditsine (obzor literatury).

The practical importance of the main genetic infringements in diagnostics of a wide circle of illnesses, including cardiology, nephrology, and oncology. Methods used. The exclusive effectiveness of application of the polymerasic chain reaction in the purposes of diagnostic. Expediency of application of the molecular-genetic methods for radiating, chemical and extreme effects evaluation.

[Long-term ecological and genetic consequences of use of dioxin-containing environmental agents]. / Otdalennye ékologo-geneticheskie posledstviia vozdeistviia doksinosoderzhashchimi ékotoksinami.

The long-term consequences of the use of dioxine-containing ecotoxic agents in the USA in 1961-1972 are ecologically and genetically characterized. There were increases in the incidence of pathological reproductive events in the contaminated region. It is concluded that there will be higher probability of abnormalities in the families of individuals born at war or just thereof. An association of impaired reproduction with functional disorders and women's poorer health, with higher incidence of somatic and gynecological diseases (chronic ones in particular) is shown. Cytogenetic changes in the lymphocytes were found in individuals from exposure risk groups. The contribution of chromosomal alterations observed in the contaminated area to immunodeficiency is appreciated. The systemic pattern of the action of biologically active properties of dioxine was demonstrated from the morphofunctional changes of different cell types. Cluster analysis revealed associations of cytogenetic parameters with the integrated index of health status in individuals from different contaminated areas. The ecological and genetic consequences may be regarded as part of homeostatic changes at many levels, as suggested by a correlation between the genetic instability and the changes occurring in other tissues, organs, and systems.

[The effect of perftoran on the resistance of mice to GABA receptor antagonists and on the antidote activity of anticonvulsant agents]. / Vliianie perftorana na ustoichivost' myshei k antagonistam GAMK-retseptorov i antidotnuiu aktivnost' protivosudorozhnykh sredstv.

Perfluorane (a phenobarbital-type inducer of the microsomal enzyme system) raised the resistance of mice to the toxic effect of picrotoxin and bicucullin in 7 days after injection. The antidote effect of diazepam and phenobarbital increased under such conditions. In experiments in vitro a modulatory effect of perftorane on the central muscarine and benzodiazepine receptors was demonstrated.