Comprehensive Study of the Liquid Expanded-Liquid Condensed Phase Transition in 1,2-Dimyristoyl-sn-glycero-3-phospho-l-serine Monolayers: Surface Pressure, Volta Potential, X-ray Reflectivity, and Molecular Dynamics Modeling.

An integrated approach is applied to reveal fine changes in the surface-normal structure of 1,2-dimyristoyl-sn-glycero-3-phospho-l-serine (DMPS) monolayers at the air-lipid-water interface occurring in a liquid expanded (LE)-liquid condensed (LC) transition. The combination of the Langmuir monolayer technique, X-ray reflectometry, and molecular dynamics (MD) modeling provides new insight into the molecular nature of electrostatic phenomena in different stages of lipid compression. A homemade setup with a laboratory X-ray source (λ = 1.54 Å) offers a nondestructive way to reveal the structural difference between the LE and LC phases of the lipid. The electron density profile in the direction normal to the interface is recovered from the X-ray reflectivity data with the use of both model-independent and model-based approaches. MD simulations of the DMPS monolayer are performed for several areas per lipid using the all-atom force field. Using the conventional theory of capillary waves, a comparison is made between the electron density profiles reconstructed from the X-ray data and those calculated directly from MD modeling, which demonstrates remarkable agreement between the experiment and simulations for all selected lipid densities. This confirms the validity of the simulations and allows an analysis of the contributions of the hydrophobic tails and hydrated polar groups to the electron density profile and to the dipole component of the electric field at the interface. According to the MD data, the dependence of the Volta potential on the area per lipid in the monolayer has a different molecular nature below and above the phase transition. In the LE state of the monolayer, the potential is determined mostly by the oriented water molecules in the polar region of the lipid. In the LE-LC transition, these molecules are displaced to the bulk, and their effect on the Volta potential becomes insignificant compared with the contribution of the hydrophobic tails. The hydrophobic tails are highly ordered in the state of the liquid crystal so that their dipole moments entirely determine the growth of the potential upon compression up to the monolayer collapse.

Molecular Dynamics Modeling of the Interaction of Cationic Fluorescent Lipid Peroxidation-Sensitive Probes with the Mitochondrial Membrane.

Cardiolipin (CL) plays a central role in lipid peroxidation (LPO) of the mitochondrial inner membrane due to higher content of unsaturated fatty acids in CL in comparison with the other phospholipids. CL oxidation plays an important role in the regulation of various intracellular signaling pathways and its excessive oxidation contributes to the development of various pathologies and, possibly, participates in the aging process. Mitochondria-targeted antioxidants containing triphenylphosphonium (TPP+) effectively protect CL from oxidation. It is assumed that fluorescent probes on the basis of the C11-BODIPY fluorophore sensitive to LPO and containing TPP+ can selectively register CL oxidation. To test this possibility, we carried out a molecular dynamic simulation of such probes in a model mitochondrial membrane. It is shown that the probes are located in the membrane at the same depth as the unsaturated bonds in CL molecules sensitive to oxidation. Increasing the length of the linker that binds the fluorophore and TPP+ residue ha little effect on the position of the probe in the membrane. This indicates the possibility of modifying the linker to increase the selectivity of the probes to CL.

[Hox Genes and Animal Regeneration].

The concept of regeneration is intimately associated with ideas about positional information, that is, the distribution of various signals prescribing cells their location in an embryo or an adult organism. Hox genes are perfect candidates for the role of factors creating positional information. Their main function is thought to be regionalization of the embryo and the determination of the anterior/posterior (A/P) axis of the bilaterian body according to the rules of temporal and spatial colinearity. At the same time, Hox genes are also expressed postembryonically and may participate in various processes in the adult body. In particular, Hox genes are involved in regeneration, as shown on animals from different evolutionary clades. During reparation Hox genes are responsible for regionalization and specification of the newly formed structures, which reflects their embryonic role. This is not all, however. Hox transcription patterns in some adult organisms and their expression dynamics after damage suggest that Hox genes are involved in creating positional information in the adult body. This information is necessary for consistent reparation, while its fast reorganization may accelerate the reparative process.

Conformational and phase transitions in DNA--photosensitive surfactant solutions: Experiment and modeling.

DNA binding to trans- and cis-isomers of azobenzene containing cationic surfactant in 5 mM NaCl solution was investigated by the methods of dynamic light scattering (DLS), low-gradient viscometry (LGV), atomic force microscopy (AFM), circular dichroism (CD), gel electrophoresis (GE), flow birefringence (FB), UV-Vis spectrophotometry. Light-responsive conformational transitions of DNA in complex with photosensitive surfactant, changes in DNA optical anisotropy and persistent length, phase transition of DNA into nanoparticles induced by high surfactant concentration, as well as transformation of surfactant conformation under its binding to macromolecule were studied. Computer simulations of micelles formation for cis- and trans-isomers of azobenzene containing surfactant, as well as DNA-surfactant interaction, were carried out. Phase diagram for DNA-surfactant solutions was designed. The possibility to reverse the DNA packaging induced by surfactant binding with the dilution and light irradiation was shown.

Karyotype evolution of giraffes (Giraffa camelopardalis) revealed by cross-species chromosome painting with Chinese muntjac (Muntiacus reevesi) and human (Homo sapiens) paints.

Considering the giraffe (Giraffa camelopardalis, GCA, 2n = 30) as a primitive species, its comparative genomic data are critical for our understanding of the karyotype evolution of pecorans. Here, we have established genome-wide chromosomal homologies between giraffe, Chinese muntjac (Muntiacus reevesi, MRE, 2n = 46) and human (Homo sapiens, HSA, 2n = 46) with whole sets of chromosome-specific paints from Chinese muntjac and human, in addition to providing a high-resolution G-banding karyotype of giraffe. Chinese muntjac and human chromosome paints detected 32 and 45 autosomal homologs in the genome of giraffe, respectively. Our results suggest that it would require at least thirteen fissions, six fusions and three intrachromosomal rearrangements to 'transform' the 2n = 44 eutherian ancestral karyotype to the 2n = 58 pecoran ancestral karyotype. During giraffe evolution, some ancestral eutherian syntenies (i.e. association of HSA3/21, 4/8, 7/16, 14/15, 16/19 and two forms of 12/22) have been retained, while several derived syntenies (i.e. associations of human homologous segments 2/1, 2/9, 5/19, 4/12/22, 8/9, and 10/20) have been produced. The reduction of chromosome number in giraffe from the 2n = 58 pecoran ancestral karyotype could be primarily attributed to extensive Robertsonian translocations of ancestral chromosomal segments. More complex chromosomal rearrangements (including tandem fusion, centromere repositioning and pericentric inversion) have happened during the evolution of GCA2 and GCA8.

Studies on the current 137Cs body burden of children in Belarus--can the dose be further reduced?

After the Chernobyl reactor accident wide areas of Belarus were contaminated with radioactive fallout. The verification and documentation of the long-term development of radiation doses is still going on. A population group of special concern are the children living in contaminated regions. The annual dose limit of 1 mSv is still exceeded in some cases, essentially due to high body burdens of 137Cs as indicated by screening measurements with portable incorporation monitors. In this situation the evaluation of possible dose reduction measures in addition to the control of food contamination is being investigated. Special attention is given to the therapeutic application of a pectin preparation (Vitapect), for which a dose-lowering effect is presumed by Belarusian scientists. In a placebo-controlled double-blind study, several groups of contaminated children received a pectin compound named Vitapect for a two-week period during their stay in a sanatorium. For comparison the same number of control groups were given a placebo preparation. The 137Cs body burden of the children was measured at the beginning and the end. The mean relative reduction of the specific activity within the Vitapect groups was found to be approximately 33%, whereas the specific activity of the children who received a placebo decreased only by approximately 14%, due to clean food supply. It is known that pectins chemically bind cations like caesium in the gastrointestinal tract and thereby increase faecal excretion. Theoretical calculations based on this assumption and considering metabolism processes are qualitatively consistent with the experimentally found retention of radiocaesium in the human body after pectin treatment.

Bound-state approach to the QCD coupling constant at low-energy scales.

We exploit theoretical results on the meson spectrum within the framework of a Bethe-Salpeter (BS) formalism adjusted for QCD, in order to extract an experimental coupling alpha(s)exp (Q2) below 1 GeV by comparison with the data. Our results for alpha(s)exp (Q2) exhibit a good agreement with the infrared safe analytic perturbation theory (APT) coupling from 1 GeV down to 200 MeV. As a main result, we claim that the combined BS-APT theoretical scheme provides us with a rather satisfactory correlated understanding of very high- and low-energy phenomena.

[A role of the motor-and-active forms of training in lifestyle formation and health promotion in schoolchildren].

The motor-and-active forms of training were studied for their impact on the health status, moral, business, and social qualities of children and adolescents. The school-children's health was found to be worse, which was attended by a rise in the total morbidity, which was 9.3 times higher in pupils from general educational classes. The lifestyle of today's young people has some negative aspects: the early onset of smoking, alcoholic use, and sexual life. The goal-oriented educational work promotes the formation of healthy lifestyle in children and adolescents--their striving for harmonic physical development, achievement of sports results, leads to a significant reduction in the number of smokers and alcohol users in a more problematic section of pupils. The diet in adolescents is unbalanced, has inadequate caloric value and does not meet the rational nutrition principles (predominance of calorie consumption over energy expenditure), and it needs to be corrected.

Reducing the 137Cs-load in the organism of "Chernobyl" children with apple-pectin.

As a complement of standard radioprotective measures, apple-pectin preparations are given, especially in the Ukraine, to reduce the 137Cs uptake in the organism of children. The question has been raised: is oral pectin also useful when children receive radiologically clean food, or does this polysaccharide only act in binding 137Cs in the gut, blocking its intestinal absorption? In this case, pectin would be useless if radiologically clean food could be given. The study was a randomised, double blind placebo-controlled trial comparing the efficacy of a dry and milled apple-extract containing 15-16% pectin with a similar placebo-powder, in 64 children originating from the same group of contaminated villages of the Gomel oblast. The average 137Cs load was of about 30 Bq/kg bodyweight (BW). The trial was conducted during the simultaneous one-month stay in the sanatorium Silver Spring. In this clean radiological environment only radiologically "clean" food is given to the children. The average reduction of the 137Cs levels in children receiving oral pectin powder was 62.6%, the reduction with "clean" food and placebo was 13.9%, the difference being statistically significant (p <0.01). The reduction of the 137Cs load is medically relevant, as no child in the placebo group reached values below 20 Bq/kg BW (which is considered by Bandazhevsky as potentially associated with specific pathological tissue damages), with an average value of 25.8 +/- 0.8 Bq/kg. The highest value in the apple-pectin group was 15.4 Bq/kg, the average value being 11.3 +/- 0.6 Bq/kg BW.

[Variants of the treatment of critical states with consideration of the pathogenesis of the systemic inflammatory response syndrome]. / Varianty lecheniia kriticheskikh sostoianii s uchetom patogeneza SIRS-sindroma sistemnogo vospalitel'nogo otveta.

A total of 182 critical patients with sepsis (n = 62), prolonged compression syndrome (PCS) (n = 41), toxic allergic dermatitis (TAD) presenting as Lyell's and Stevens-Johnson's syndromes (n = 54), and stages I-II status asthmaticus (SA) (n = 25) were examined. Statistical computer processing of the data by the method of comparing the means and analysis of correlations revealed a cascade of numerous mediators and metabolites which can be regarded as manifestations of the systemic inflammatory response syndrome (SIRS). This syndrome develops as a reaction to infection, toxic products of microorganisms, ischemic reperfusion lesions, and humoral cytotoxic reactions and is responsible for the formation of multiple organ disorders. Inefficiency of 7-10-day traditional intensive care necessitated active repair of the natural defense mechanisms and addition to the therapeutic complexes of hemo- and plasmaxenosplenoperfusion variants developed by the authors. Despite multiple organ disorders, splenoperfusion decreased the period of critical state from 24 to 12 days in sepsis, from 28 to 18 days in TAD, from 14 to 10 days in PCS, and from 17 to 7 days in SA. The mortality in sepsis dropped from 32.4 to 8%, in TAD from 10.7 to 4%, in PCS from 38.8 to 14.7%, and in SA from 15.9 to 5%. No additional drug therapy or equipment was needed.

[Neurocirculatory dystonia: views on its etiology, pathogenesis and methods of therapy]. / Neirotsirkuliatornaia distoniia: vzgliady na étiologiiu, patogenez, metody terapii.

Basing on their psychophysiological, immunological and clinical findings, the authors emphasize the role of chronic infection, occupational hazards, adaptation to new climatic and social environment in pathogenesis of neurocirculatory asthenia (NA). The disease is also associated with sensitization to streptococcus, allergization, adverse effects of circulating immune complexes, impaired relationships between CNS and immune system. It is suggested that NA arises consequently to genetic determination of regulation process desynchronization. A new effective NA treatment is proposed comprising in addition to conventional treatment a course of UHF-inductothermia to the chest and anterior mediastinum conducted in conditions of short-term and low-intensity regimen of the exposure.

[A clinical and morphological study of status asthmaticus]. / Kliniko-morfologicheskoe issledovanie pri astmaticheskom statuse.

Clinical and morphologic studies were carried out in 230 patients suffering a grave course of an exacerbation of infectious bronchial asthma. A protracted attack of the condition was detected in 70 patients, in 80 patients status asthmaticus, Stages I-II was found, 50 patients suffered a Stage III status asthmaticus, and 30 patients were hospitalized in the terminal state and died within 12 hours since admission. The circulatory, metabolic, immunologic homeostasis parameters were studied, morphologic, examination of pulmonary, tracheal, cardiac, cerebral, splenic and hepatic tissue was carried out in 30 patients who died at the height of the status asthmaticus. The authors have analyzed the contribution of the homeostasis parameters to the formation of the critical state in status asthmaticus and the relationships of these parameters between each other and with the condition severity. The severity of the patients' condition was found closely related to the degree of respiratory, circulatory, and metabolic disturbances. Respiratory failure and circulatory disorders were the principal clinical manifestations of status asthmaticus, though the disorders of the metabolic and immunologic homeostasis also much contributed to the formation of a critical condition due to status asthmaticus. Characteristic histomorphologic changes of the viscera, detected at autopsy, were the morphologic equivalent of these clinical symptoms. The findings regarding status asthmaticus as a critical state that is characterized by the development of multiorgan insufficiency involving the formation of incompetence of natural detoxication routes.

[The prognosis and prevention of syncopal states and sudden death in patients with a complete atrioventricular block in disorders of permanent cardiac electrostimulation]. / Prognozirovanie i profilaktika sinkopal'nykh sostoianii i vnezapnoi smerti u bol'nykh s polnoi atrioventrikuliarnoi blokadoi pri narusheniiakh postoiannoi élektrikardiostimuliatsii.

A total of 105 patients with implantable pacemakers were examined. Whether the pacemaker disconnection test can be used to predict syncopes in failure of permanent cardiac pacing was studied. The spontaneous ventricular activity was evaluated in 62 patients with acquired complete atrioventricular block (CAVB) and in 43 patients with artificial CAVB. The patients with varying pacemaker dependence were grouped. It was ascertained that 7% of patients with artificial CAVB and 19% of those with acquired CAVB were dependent on pacemakers. In possible failure of stimulation or in reimplantation of a pacemaker on its disconnection, 93% of patients with artificial CAVB and 81% with acquired CAVB could develop their own cardiac rhythm. Lowering the frequency of pacing enabled the duration of asystole to be decreased. The usage of isadrin was demonstrated to enhance spontaneous ventricular activity.