Background: In modern medicine, various technical means and developments are actively used in invasive intravascular (IVL) and non-invasive transcutaneous blood irradiation methods, including low-intensity laser radiation (LLLR) of various ranges. Despite the positive clinical results of such exposure, the physical and molecular mechanisms remain incompletely understood. Ultraviolet (UV) and terahertz (THz) ranges of electromagnetic radiation are classified as biogenic; therefore, establishing their effects at the level of blood cells will allow them to be recommended for use in medical and biotechnological practice after the development of appropriate exposure methods. The objective was to study the biogenic activity of ultraviolet (UV) and terahertz (THz) ranges of LLLR on the structural and functional state of red blood cells of rats in vitro. Materials and methods: Using methods of microelectrophoresis, spectrophotometry and chemical erythrograms, the following was studied: zeta potential of red blood cells; the content of the primary products of lipid peroxidation in the red blood cells (fatty acid conjugates of membrane of red blood cells phospholipids — diene (DK), triene (TK), and tetraene (TTK), oxodiene (ODK); resistance of erythrocytes to the action of an acid hemolytic after previous laser irradiation in the UV and THz ranges. Laser irradiation of the samples in the UV range was carried out by a nitrogen pulsed laser (λ = 0.337 μm), with the average radiation power 5 mW; irradiation in the THz range with a continuous CO2 laser (λ = 118.8 μm), the average radiation power is 20 mW. When the samples were irradiated, the density of radiation power W did not exceed 7 W/m2. The exposure dose under nitrogen laser irradiation was D1UV=0.109 J/cm2, D2UV=0.327 J/cm2, D3UV=0.546 J/cm2. Under CO2 laser irradiation, the exposure dose was D1THz=0.624 J/cm2, D2THz=1.871 J/cm2, D3THz=3.119 J/cm2. The thickness of irradiated red blood cell suspension layer was 1 mm. Results: The effect of low-dose LLLR UV and THz radiation causes physicochemical changes in the plasma membrane of erythrocytes. A nonlinear dose-dependent decrease in the electrokinetic potential of the cell surface and an increase in the hemolytic sensitivity of erythrocytes against the background of activation of lipid peroxidation processes in erythrocyte membranes have been established. Conclusions: Under the influence of LLLR, the free-radical peroxidation of lipids of erythrocyte membranes is stimulated. Pronounced biogenic activity of UV of LLLR was detected at the level of erythrocyte membranes. The obtained data can be used to expand the spectrum of application of LLLR of the UV range in IVL techniques.

Background: The impact of low-dosed ionizing radiation (IR) itself and in combination with the other damaging physical factors such as extremely high frequency (EHF) microwaves and magnetic fields (MF) is currently the object of numerous researches. Results of those investigations, however, still didn’t lead to certain unequivocal conclusions. Objectives: This paper presents the review and analysis of previously conducted experimental series in comparison with adjacent-aimed works to make a step forward in understanding the role of low doses of ionizing, non-ionizing radiation and magnetic field in the development of cellular effects. Results: Ultra-low doses of both IR itself and with EHF and MF have triggering effects which included variability of IR effect modification; the significance of even non-ionizing radiation effects was shown on the example of ultra-wideband microwaves irradiation. Combined effects from gamma-IR with EHF microwaves and MF on chromatin led to decrease of heterochromatin granules quantity (HGQ) but affected the cell membrane permeability (CMP) rate greater than IR itself. Mitochondrial activity inhibition and cytoplasm Ca2+ decrease was detected under exposure to both IR and EHF-microwaves and their combination; MF slightly increased mitochondrial membrane potential and showed no significant changes in Ca2+ migration to the nucleus when applied together with IR. Exposure to neutron radiation revealed the maximum of chromatin condensation rate and cell membrane permeability up to the dose 36.5 mSv. Further dose increase returned the state of chromatin and cell membrane to control levels. Conclusions: Vague effect of ultra-low doses of IR with modifying abilities of EHF-microwaves and MF was shown on the example of HGQ. Effects of high doses of gamma-radiation were also modified by both EHF-microwaves and MF at indexes of HGQ (decrease), CMP (increase), mitochondrial activity (decrease) and Ca2+ nucleus/cytoplasm redistribution. Irradiation with fast neutrons in low-to-medium dose range led to the development of cell stress signs (HGQ/CMP increase) which were smoothed under the dose increase.

Background: The problem of drug delivery to the tissue-damaged area of the human body remains relevant. Hydroxyapatite (HA), as one of the best known calcium phosphate (CaP) compounds, is used as an inorganic component of composite materials for drug loading. The organic components in composite materials are biopolymers such as alginate, agarose, chitosan (CS), collagen, and gelatin. Selected C60 nanoparticles are widely used as antibacterial agents and can strengthen the structure of composites. Microwave (MW) irradiation is an exposure method that shortens the synthesis time by significantly increasing the number of nucleation centers, which results the reducing the size of the crystallites formed, which affects the adsorption capacity of the product. Objectives: Most forms of drug delivery systems demonstrate rapid release of ceftriaxone (CFT) and anasthesin (ANA) within 2 days, characterized by a "burst release" that may cause overdose in the first hours of use. The aim of this work was to investigate and compare the drug release kinetics from convectionally and MW-synthesized CS matrices modified with HA, multiphasic CaP, and fullerene C60 nanoparticles for long-term bone tissue regeneration. Materials and methods: The study was performed by high-performance liquid chromatography (HPLC) using an Agilent 1200 device with a DAD detector (λ = 210–270 nm) and a C18 chromatographic column (Zorbax SB-C18 4.6×150 mm, 5 μm) at ambient temperature. Results: HA is a good adsorbent, but a poorly soluble substance, so the pharmacokinetics of ANA release was mainly determined by the degree of adsorption of the drug on the surface of the material and its diffusion potential. CS and C60 in the composition provide a prolonged release of ANA for up to 18 days. The release of CFT from CaP/CS matrices depends on the method of its introduction into the composite - during synthesis or saturation after synthesis. The saturation method is characterized by a fast release range of 24–48 hours, and adding during synthesis delays active release to 48–72 hours (start of degradation). The release index took values from n = 0.56 to n = 0.92, which corresponds to the release kinetics that does not follow Fick's law, and close to the first-order release kinetics model. Conclusions: Synthesized composites based on a CS matrix modified with nanostructured CaP particles and fullerene C60 are potential carriers of CFT and ANA with the function of their long-term release in areas of bone tissue injury.

Background: The study of physical and molecular mechanisms of the influence of low-level laser radiation (LLLR) of a wide frequency range on biological objects allows to clarify the problem of laser photomodulation at the level of natural biological membranes and their model analogues. Objectives: Identification of molecular and physical mechanisms of the influence of LLLR of a wide frequency range on biological objects of various levels of complexity. Materials and methods: Research objects: unicellular organisms S. cerevisiae, concentration of cells in the sample 18×106; model lipid membranes from a mixture of phosphatidylcholine and cardiolipin with different content of components (10%, 20% and 40% cardiolipin), which simulates the surface electrical properties of lipid models. A spectrophotometric study of charge redistribution on the cell surface was carried out using bromothymol blue dye. Complex formation of cytochrome c with model membranes was studied spectrophotometrically at the wavelength of the Soret band (405–410 nm). The influence of low-intensity laser radiation with wavelength and power density, respectively: 337 nm, 2.8 mW/cm2; 532 nm, 9.5 mW/cm2; 70.5 μm, 10.0 mW/cm2 on the yeast cell surface; 632.8 nm, 5.1 mW/cm2 on liposomes with different protein-lipid composition. Results: LLLR of a wide frequency range causes a change in the surface electrical properties of S. cerevisiae cells, namely, a redistribution of the surface charges of the cell membrane, as a result of which a change in the surface membrane potential is recorded. Irradiation of samples of model lipid membranes with a helium-neon laser leads to a change in the surface characteristics of liposomes, which affects the kinetic parameters of the formation of protein-lipid complexes with the participation of cytochrome c. Conclusions: The target of laser photomodulation processes is the surface of the biological membrane of both natural cells, for example yeast cells, and model lipid membranes made of a mixture of phospholipids with different content of components. The creation of lipid models based on the protein and lipid composition of natural membranes makes it possible to predict the reaction of cell membranes to the action of LLLR in the model, and to understand the molecular mechanisms of laser photomodulation processes.

The article is devoted to the 2nd Scientific workshop for students “Computational physics of DNA”.

Background: Recovery of biomechanical parameters of contraction of muscles damaged by alcoholic myopathy is a rather complex and long-term process. Therefore, the search for effective therapeutic means for its acceleration is an extremely urgent task in biomedicine. Aim of work: The effect of C60 fullerene aqueous solution (C60FAS) on the dynamics of skeletal muscle contraction in rats after 9 months of chronic alcoholization and 2 months after cessation of alcohol consumption was investigated. Materials and Methods: When analyzing the miotic response using tensometry, such biomechanical parameters as the time of reduction of the muscle force response by 50% from the initial value, the values of the contraction force and the impulse of the muscle force were evaluated. Results: It has been shown that animals orally administered alcohol and C60FAS (daily dose of 1 mg/kg) together (scheme II) during the experiment showed an increase in muscle force response by 40–45±2% compared with the group of alcoholized animals and by 12–15±1% compared with the group of rats administered C60FAS 1 h after alcohol ingestion (scheme I). The positive effect of C60FAS administration according to scheme II and scheme I was 34±2% and 10±1%, respectively, compared with the group of alcoholized animals in the case of recording the time of reduction of the muscle force response by 50% of the initial value. After 2 months of rehabilitation, the level of minimum muscle contraction force when using C60FAS in both schemes differed by about 15±1% compared to the group of alcoholized animals, and the time of reduction of the force response by 50% was not significantly recorded. Finally, the use of C60FAS revealed a significant increase in the magnitude of the muscle force impulse: up to 86±4% (scheme I) and almost to control values — 94±2% (scheme II). Conclusions: The obtained results indicate the prospects of using C60FAS to restore the biomechanical parameters of skeletal muscle contraction during long-term development of alcoholic myopathy.

Background: Currently, an increase in the number of new cases of Covid-19 caused by the severe acute respiratory syndrome virus (SARS-CoV-2) is recorded in Ukraine and the world. SARS-CoV-2 provokes exacerbation of chronic diseases and activates inflammatory and allergic reactions. A severe course of Covid-19 increases the duration of hospitalization and the mortality rate among the population. Pathogenetic therapy is carried out with systemic corticosteroids, which suppress the cytokine storm by mitigating the SARS-CoV-2-induced systemic inflammatory response and inhibit SARS-CoV-2 main protease Mpro, a key component of viral replication. Objectives: The aim of this study is to identify the potential corticosteroid binding sites on SARS CoV-2 main protease Mpro based on the analysis of the energetic and topological characteristics of the complexes as well as to investigate the inhibitory activity of selected corticosteroids against Mpro. Material and Methods: The crystal structure of Mpro (ID: 6LU7 from Protein Data Bank) (www.rcsb.org) was chosen as a docking target. Molecular docking methods (AutoDock Tools 1.5.7, AutoDock Vina 1.1.2) were used to gain insight into the binding affinity Mpro with systemic corticosteroids such as dexamethasone (DEX), prednisone (PRED), prednisolone (PNL), methylprednisolone (Medrol), triamcinolone (TAC), and hydrocortisone (HCT). Visualization of docking results was done in PyMol 2.5. The protein-ligand interaction profiler (PLIP) and the LigPlot+ web tool were used to identify non-covalent interactions between Mpro and ligands (https://plip-tool.biotec.tu-dresden.de). Results: In silico docking study demonstrated that all selected corticosteroids bound with amino acid residues of II and III domains of Mpro with binding energy in the range -7.8…-6.6 kcal/mol. The high binding affinity is found for dexamethasone-Mpro (-7.8 kcal/mol); for prednisone, prednisolone, methylprednisolone, triamcinolone, and hydrocortisone the binding energies were -7.4, -7.0, -7.5, -7.6 and -6.6 kcal/mol, respectively. It was shown that hydrogen bonds and hydrophobic interactions were involved in the formation of ligand-protein complexes mainly through residues such as Arg131, Lys137, Thr199, Asp289, Leu272, Leu286, Leu287, Tyr239, and Gly275, which formed the catalytic and distal sites for ligand binding. The inhibition constant of corticosteroids has ranged from 1.90 × 10-6 to 14.4 × 10-6 M. Conclusion: Our results showed that the favorable binding sites for dexamethasone, prednisone, methylprednisolone, and triamcinolone are located in the catalytic site of domain II and the distal site of domain III of SARS-CoV-2 main protease Mpro with high binding affinities confirming the stability of the complexes. The low inhibition constants values for dexamethasone, prednisone, methylprednisolone, and triamcinolone further confirm the effectiveness of the selected corticosteroids as inhibitors of Mpro activity. Based on the binding energy as well as inhibition constants values dexamethasone, prednisone, methylprednisolone, and triamcinolone were identified as potential inhibitors for Mpro.

Background: Computer tomography is recognized as one of the most powerful methods for diagnosis, and monitoring of a wide range of diseases. It provides the ability to obtain detailed information about the internal structure of organs and bones. Despite the success of computed tomography in areas such as three-dimensional mammography or lung radiography, it has not achieved the same level of widespread as, for example, magnetic resonance imaging, even if CT offers greater accuracy. This is primarily due to safety limitations on the permissible number of examinations due to the harmfulness of X-ray radiation to the patient. One of the main challenges facing researchers is the need to reduce the time of the entire examination and decrease the radiation exposure to the patient. Overcoming these challenges is crucial for improving the overall efficiency of medical services, optimizing treatment plans, and ultimately enhancing patient outcomes. Thus, addressing these issues through innovative algorithms and methods in computed tomography holds significant potential for revolutionizing medical diagnostics and ensuring continuous progress in modern healthcare. Objectives: The aim of this work was to develop an algorithm for three-dimensional reconstruction that is independent of the conicity of the radiation beam. Therefore, it allows for accurate reconstruction of the entire object with a single rotation of the radiation source around the investigated object. Materials and Methods: The work utilizes methods of integral transforms and computer modeling to solve inverse problems arising in computer tomography. Results: An analytical inversion formula was obtained for three-dimensional computer tomography with linear scan geometry and segmentation. The feasibility of the developed algorithm was verified, and a methodology for research with linear motion of the conical emitter and detectors was developed. Conclusions: The developed algorithm improves the reconstruction of object layers significantly distant from the plane in which the emitter and detector move, compared to existing algorithms.