Vol 69, No 2 (2024)

A method for analyzing intramolecular vibrations of the amino acid like glycine, diphenylalanine and tryptophan in terahertz and infrared electric fields has been implemented with Fourier frequency spectrum calculation of the integral dipole moment amplitude-time realizations. Realizations lasting up to 2 ns were obtained by supercomputer modeling with a sampling step of 1 fs. The results obtained showed new possibilities of applying this method, in which the electric field simulated with a symmetrical meander was used for the first time. Our findings deepen the current understanding about dynamic properties of biomoleculaes in external electromagnetic radiation. These data can also be used in the development of nanobiotechnologies, bioelectronic and heterogenous hybrid microelectronic devices with embedded biomolecular components.

The formation of short DNA fragments, up to 3 kbp, induced in chromatin by nitrogen (LET 97 keV/mм) and iron (LET 190 keV/mм) ions was studied by computer simulation. Chromatin models with different structure parameters and Monte Carlo track structure simulation were used to assess the impact of chromatin fiber structure and LET on the DNA fragment size distribution. For the structures modeled (different types of solenoids, a chain of nucleosomes), the fragment size distribution had a maximum in the region of ~100 bp corresponding to the formation of DNA breaks in two neighboring turns of the helix on the nucleosome. The calculation predicted the peak in the region of ~1000 bp, corresponding to the formation of DNA breaks in two neighboring turns of the solenoid, which parameters depended on the degree of compactness of the fiber and were independent of LET. The assumption was introduced of the presence of subpopulations of various chromatin structures under irradiation. It allowed to explain the experimentally observed size distributions of the short DNA fragments induced by high-LET charged particles.

It has previously been shown that heteroaromatic antioxidant oxibiol (N-acetylcysteinate 6-hydroxy-2-aminobenzothiazole) inhibits the process of fructosylation of serum albumin. The aim of this study is to elucidate the inhibitory effect of oxibiol on modification of proteins by photodegradation products of bisretinoid A2E, the main fluorophore of lipofuscin granules in retinal pigment epithelial cells of the human eye. It was shown that unlike a water-soluble fraction fraction from non-irradiated A2E-liposomes, a water-soluble fraction formed after irradiation of A2E-liposomes with visible light significantly modified albumin in a day after incubation at 37°C. Oxibiol in millimolar concentrations effectively inhibited this process. The inhibitory effect of oxybiol could be attributed to its antioxidant activity and the ability to compete with reactive aldehydes formed during the photooxidative degradation of A2E-cardiolipin liposomes. The acute toxicity of oxibiol in mice after intraperitoneal injection was studied, the values of LD 10 and LD 50 were determined. The results obtained demonstrate that oxibiol can be used in pharmacology for preventing and curing diseases associated with the development of oxidative stress in various fields of medicine, primarily in ophthalmology.

The effect of ambiol, a plant growth regulator, on the functional state of mitochondria of etiolated pea seedlings has been studied. The drug prevented the activation of lipid peroxidation in mitochondrial membranes in the concentration range of 10–5–10–6 and 10–9 M. The addition of ambiol to the incubation medium of these organelles led to an increase in the oxidation rates of NAD-dependent substrates. At the same time, the most effective concentrations were 10–5 and 10–6 M. Changes in the bioenergetic characteristics of mitochondria were accompanied by alterations in the fatty acid composition of mitochondrial membranes. The most significant changes were observed in the content of 18:2 ω6 and 18:3 ω3 fatty acids. It is assumed that an increase in the content of these fatty acids in the mitochondrial membranes may indicate an increase in the content of cardiolipin, which provides the effective functioning of the mitochondrial respiratory chain, and, consequently, plays an essential role in the maintenance of high-energy-level metabolism. Treatment of pea seeds with ambiol not only prevented a decrease in the growth rate of pea seedlings under water-deficit conditions, but also stimulated their growth.

Nitric oxide is a signaling molecule of plants under stressful conditions, and also this molecule can have a toxic effect. This study focused on investigation of a dose-dependent effect of the nitric oxide donor, sodiumμ2-dithiosulphate-tetranitrosyl diferrate tetrahydrate, on the structural state of mitochondrial membranes of epicotyls of pea seedlings. Treatment of mitochondria with 10–8 M of this drug led to thermo-induced structural transitions within the temperature range from 15°C to 21°C and from 30°C to 36°C in the lipid regions, and within the temperature range from 12°C to 15°C and from 27°С to 33°С in preprotein regions of membranes. In the lipid regions of the membranes, the compound exhibited antioxidant activity, leading to accumulation of long unsaturated fatty acids. Treatment of mitochondria with 10–4 M sodium-μ2-dithiosulphatetetranitrosyl diferrate tetrahydrate most likely led to a significant increase of the lipid peroxidation level and membrane lipid phase fluidity.

The transport of calcium ions across the cardiomyocyte cellular membrane is associated with crossing a high energy barrier and can be dysregulated by the vibration. Calcium channel blockers are a group of medication that reduce damage of mitochondria and cell membranes. In this study, the effects of nifedipine (adalat), a calcium channel blocker drug, 7.5 mg/kg on energy metabolism of cardiomyocytes which underwent vibration induced hypoxia (exposure to 56 vibration sessions at a single frequency, 44 Hz with an amplitude of 0.5 mm) were evaluated. The functional states of mitochondria in 30% rabbit left ventricular myocardial tissue homogenate were studied polarographically using a closed galvanic oxygen sensor in a 1 ml cuvette with thermostatic holder, the protein concentration in the system was 2.4 ± 0.5 mg and a modified microbiuret method was used for protein determination. In animals injected with calcium channel blockers and exposed to vibration, the rate of endogenous respiration (V e) remained at the level as in intact animals and was 16.4 ± 4.1 [ng-atom O] min–1mg–1 protein, amytal sensitivity increased by 39%, and malonate sensitivity decreased by 40% as compared to animals that were not injected with calcium channel blockers but exposed to vibration. The indices of the ratio of the activity of mitochondrial enzyme complex I and complex II and the processes of regulation of mitochondria in different metabolic states indicate that the activity of mitochondrial complex I , inhibited by vibration, is restored and mitochondrial complex II exhibits limited regulatory functions. This study has shown the energy-protective action of calcium channel blockers, due to which tissue resistance in response to vibration increases, thereby preventing the development of necrotic changes in the tissue.

Combined effects of electrolysis and ultrasound on the population of E. coli bacteria in aqueous solution of sodium sulfate were investigated. The kinetics of bacteria inactivation was determined employing these water purification techniques. It has been shown that the combination of ultrasonic and electrochemical treatments of aqueous solution significantly increases the rate of bacterial inactivation. It has been suggested that hydroxyl radicals formed as a result of the reaction occurred after treatment of aqueous solution by employing a combination of electrolysis and ultrasound are responsible for the death of bacteria. A correlation between the rate of hydroxyl radical formation and the inactivation rate of bacteria has been obtained.

FLASH radiotherapy is the innovative radiotherapy technique in which the short treatment times, few tens of milliseconds, are used to deliver a therapeutic dose of radiation to the tumor. This novel approach reduces damage and minimizes the dose to normal tissues surrounding the tumor and to tissues that are affected by radiation, whilst maintaining the treatment effect on cancer cells. This regimen may improve the level of local control of the tumor and lower the occurrence of side effects. To date, the exact radiobiological mechanisms underpinning the FLASH effect are not completely understood. The paper presents the results on the delivery of a high-intensity proton beam at an energy of 660 MeV produced by Phasotron, a proton accelerator at the Joint Institute for Nuclear Research, Dubna. This proton beam has been created to perform radiobiological studies involving cell cultures and small laboratory animals (mice, rats) using FLASH radiation. Also, the survival rates were compared between A549 cells irradiated at extremely high dose rates (FLASH technique) and those exposed to conventional irradiation with the lower dose rate. It was found that there is a difference between these groups of A549 cells in the survival rates. The magnitude of the FLASH effect is represented by a factor of different dose rates.

It has been demonstrated that “Oxacom”, a freeze-dried preparation, retains, throughout its period of storage in the ampoule in the absence of oxygen for 15 years at ambient temperature, the same hypotensive activity due to the presence of a binuclear form of dinitrosyl iron complex with glutathione. It is suggested that an oxidation reaction where glutathione ligands as constituents of dinitrosyl iron complexes react with the oxygen, the content of which gradually increase in the preparation, could lead to the degradation of these complexes, but it was prevented due to the presence of a considerable amount of free, not included in dinitrosyl iron complexes glutathione molecules in this preparation.

The paper presents an overview of image visualization techniques and other biophysical approaches that demonstrate a validity of using higher invertebrate animals that include the crustacean Daphnia magna, a member of the subphylum Crustacea as a test model for biomedical and ecotoxicological studies. The authors describe the main characteristics of animals, such as a transparent body, small size, filter feeding mechanism, the presence of the formed organs, as well as a short life cycle, high fertility and sensitivity to toxicants, which allow the use of this test organism in experiments in vivo as an alternative model to warm-blooded animals. An analysis of the existing literature on the use of D. magna as a model for visualizing the accumulation and distribution of nanomaterials in the body, as well as for analyzing the mechanisms of cytotoxicity is carried out. Methods for fluorescence imaging, interference microscopy and spectrophotometry are described.

This paper considers time series data collected over a five year interval of time on geophysical (environmental) rhythms of atmospheric pressure and geomagnetic activity and their impact on human biorhythms - blood pressure and frequency of heart rate over a longer time step than one day was evaluated. It was found that during the periods that last around 15 days, when atmospheric pressure changes smoothly and slightly, the heart beats quietly and minor fluctuations in blood pressure are observed. These "quiet" periods are mainly expected during summer months from July to August, usually only once a year. A comparison of the graphs of systolic blood pressure fluctuations with the graph of geomagnetic activity index showed that correlation coefficients between systolic blood pressure fluctuations and geomagnetic activity index were three times greater than those between systolic blood pressure and atmospheric pressure. Thus, the results obtained demonstrate that the geomagnetic field with an activity index of greater than 2 has a greater effect on elevation of systolic blood pressure in people. The analysis also showed that the intervals of the spectral peaks in spectra of atmospheric pressure are well consistent with the intervals between each heartbeat. This indicates that the heart rate of people can be influenced by synoptic processes passing through the region in the atmosphere such as cyclones and anticyclones, and, ultimately, they can affect the well-being of elderly and ill individuals. The results obtained during this study in combination with geophysical data from hydrometeorological centers can help forecast the state of human health.

Research studies conducted over the last years relating to the use of priming or the precedence effect while restoring impaired functions and cognitive rehabilitation of patients in a neurological clinic are analyzed. This paper is about the wide variety of priming, including transcranial magnetic and electrical stimulation, as well as preliminary presentation of acoustic and visual stimuli. The data presented show a wide range of conditions under which specific types of priming can be successfully used in the clinic, taking into account that the number of studies is growing every year. It is thought that the activation of neuroplasticity mechanisms underlies the positive effects of priming in the treatment of various neurological and psychogenic disorders. Based on the results obtained, the present research demonstrates that visual object priming is effective through the procedure of resonance scanning, or LED photostimulation with the frequency gradually increasing in the range of main EEG rhythms.