A computer-assisted study of the effect of gravitation on the functional state of the lungs

Gravitation influence on lung function was investigated in 115 patients and 21 healthy persons. Changing of an examinee's position from vertical into a horizontal one causes changes in lung function in health and disease. Characteristic features of lung function were determined for each group of examinees in order to improve the diagnosis and differential diagnosis of bronchial cancer and nonspecific chronic pulmonary diseases with a similar x-ray picture. A study of pulmonary ventilation and blood supply of the lungs in vertical and horizontal postures in Hodgkin's disease patients led to a conclusion that irradiation of patients seemed more effective in a phase of deep breath. It made it possible to reduce radiation exposure of healthy parts in a zone to be irradiated.     

Effect of the membrane potential on the passive transport of Ca2+ in fractions of vesicles of the myometrium sarcolemma

Using a potential-sensitive fluorescent probe diS-C3-(5), the formation of the membrane (K+-diffusion) potential, delta psi, in the myometrium sarcolemmal vesicular fraction was demonstrated. The magnitude of this potential corresponds to that calculated according to the Nernst equation, is time-stable (characteristic dissociation time--3-5 min) and temperature-dependent and is generated upon the substitution of the anion (Cl- for gluconate-) and the compensating cation (Na+ for Tris+, choline+). The change in delta psi from -61 to 0 mV leads to the activation of passive Ca2+ efflux from the vesicles (with choline+ as the compensating cation in the dilution medium). At the same value of the potential, i. e., -61 mV, the substitution of choline in the dilution medium for Na+ or Li+ stimulates the passive release of Ca2+. Co2+, Mn2+ and D-600 suppress this process by 15-20% in depolarized vesicles which points to the inhibition of Ca2+ release with an alteration of the membrane potential value from 0 to -61 mV (20%). The potential-dependent component of passive Ca2+ transport is characterized by saturation with the substrate (Km = 0.5 mM). The dependence of Ca2+ flux release from the sarcolemmal vesicles on the membrane potential value (-60-+27 mV) is bell-shaped and qualitatively relative to the volt-amper characteristics of the steady state Ca2+ flux in single smooth muscle cells. Analysis of experimental results revealed that the potential-dependent component of passive Ca2+ transport in myometrium sarcolemmal vesicles is determined by the non-activated Ca2+ conductivity of plasma membrane.     

Arthropod toxins inhibiting Ca2+ and Na+ channels prevent AC‐1001 H3 peptide‐induced apoptosis

Peptide toxins of arthropods are one of the potential sources of bioactive substances. Toxins are able to bind to calcium channels and block them. Ca²⁺ ions play an important role in many cell processes, in particular, in apoptosis. In this work, we study the effect of some arthropod toxins on intracellular processes associated with the induction of apoptosis. Synthetic analogs of U₅‐scytotoxin‐Sth1a, ω‐hexatoxin‐Hv1a, ω‐theraphotoxin‐Hhn2a, and μ‐agatoxin‐Aa1a toxins—inhibitors of calcium L, P, and Q channels and sodium channels were used in the study. Apoptosis was induced by AC‐1001 H3 peptide. We study the effect of toxins on the level of apoptosis, ROS, mitochondrial potential, GSH, and ATP in CHO‐K1 cells. We show that all the tested toxins are able to dose dependently block the induction of apoptosis triggered by AC‐1001 H3 and reduce the level of natural apoptosis in CHO‐K1 cells. Cell incubation with apoptosis inducer AC‐1001 H3 in the presence and absence of toxins causes an increase in the intracellular concentrations of ROS, ATP, and mitochondrial potential and decreases the GSH concentration. The present study reveals the antiapoptotic effect of a number of arthropod peptide toxins. The toxins studied can represent a novel approach used in the treatment of pathologies associated with the activation of apoptotic mechanisms.     

Genetic monitoring of progeny derived from natural spawning of Acipenser ruthenus Linnaeus, 1758 and Acipenser stellatus Pallas, 1771 as well as their hybrids in the Lower Volga river during the period 2017 to 2019

The state of natural spawning of sturgeons in the Lower Volga River was investigated through genetic monitoring of juveniles (larvae, fingerlings, subadults) captured at seven traditionally used monitoring locations. Sampling was performed during the period 2017–2019. In total, 460 individuals were caught and genotyped using a set of six microsatellite loci (Afug41, Afug51, Afug135, An20, AoxD161, AoxD165) and mtDNA control region sequencing. The observed species-specific microsatellite alleles revealed the presence of juvenile sturgeons originating from natural spawning also included some hybrids between Acipenser stellatus and A. ruthenus. Thus, the majority of sterlet breeding takes place in natural spawning grounds but also sterlet hybridizes with a small number of stellate sturgeons. Juveniles of other sturgeon species were not identified, and it is concluded that natural spawning activities of Russian sturgeon, beluga and ship sturgeon were insignificant or even absent in the Lower Volga during the observation period.     

Real-time technique for conversion of skin temperature into skin blood flow: human skin as a low-pass filter for thermal waves

Monitoring of skin blood flow oscillations related with mechanical activity of vessels is a very useful modality during diagnosis of peripheral hemodynamic disorders. In this study, we developed a new model and technique for real-time conversion of skin temperature into skin blood flow oscillations, and vice versa. The technique is based on the analogy between the thermal properties of the human skin and electrical properties of the special low-pass filter. Analytical and approximated impulse response functions for the low- and high-pass filters are presented. The general algorithm for the reversible conversion of temperature into blood flow is described. The proposed technique was verified using simulated or experimental data of cold stress, deep inspiratory gasp, and post-occlusive reactive hyperaemia tests. The implementation of the described technique will enable to turn a temperature sensor into a blood flow sensor.     

V. B. Krasovitski $\overset{\lower0.5em\hbox{$\overset{\lower0.5em\hbox{, Nonlinear regular oscillations in nonequilibrium plasma and gaseous media (Folio, Kharkov, 2000), vols. 1, 2

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V. B. Krasovitski $\overset{\lower0.5em\hbox{$\overset{\lower0.5em\hbox{ , Nonlinear regular oscillations in nonequilibrium plasma and gaseous media (Folio, Kharkov, 2000), vols. 1, 2     

Identification of a critical control element directing expression of the muscle-specific transcription factor MRF4 in the mouse embryo

Skeletal muscle development in the vertebrate embryo critically depends on the myogenic regulatory factors (MRFs) including MRF4 and Myf5. Both genes exhibit distinct expression patterns during mouse embryogenesis, although they are genetically closely linked with multiple regulatory elements dispersed throughout the common gene locus. MRF4 has a biphasic expression profile, first in somites and later in foetal skeletal muscles. Here, we demonstrate by transgenic analysis that elements within a 7.5-kb promoter fragment of the MRF4 gene are sufficient to drive the embryonic wave of expression very similar to the endogenous gene in somites of mouse embryos. In contrast, a 3-kb fragment of the proximal promoter fails to support expression in the myotome, suggesting that essential cis-acting elements are located between -7.5 and -3 kb upstream of MRF4. Further analysis of this sequence delimits an essential region between -6.6 and -5.6 kb that together with the 3-kb promoter fragment directs transgene expression in the epaxial myotome of all somites during the appropriate developmental period. These data provide evidence that the partly overlapping expression patterns of Mrf4 and Myf5 in somites are controlled by distinct regulatory elements. We also show that 11.4 kb sequence upstream of MRF4, including the promoter and the somitic control region identified in this study, is not sufficient to elicit target specificity towards the strong Myf5 (-58/-48 kb) enhancer, suggesting that additional yet unidentified elements are necessary to convey promoter selectivity and protect the MRF4 gene from this enhancer.