We present the results of a spectral study of the effect of low-intensity laser radiation on the molecular structure of blood and blood components. Analysis of the Fourier transform IR absorption spectra of blood confirmed the changes we observed previously in the oxygen transport characteristics of blood with intravenous exposure to the emission from a He-Ne laser. We show that structural and conformational changes in the hemoglobin tetramer, initiated by laser-induced photoreactions between Hb and oxygen, lead to characteristic changes in the shape and intensity of the IR bands for NH stretching vibrations, and also the amide I and amide II absorption bands. In the IR spectra of irradiated blood samples, we note increased absorption in the bands for stretching vibrations of the phosphate groups (945-1280 cm -1 ), which is evidence for an increase in the nucleic acid content (DNA, RNA). In the spectra of plasma and erythrocytes prepared from irradiated blood, there are no changes in this region of the IR spectrum. At the same time, in the IR spectra of samples of irradiated plasma, the intensity of the bands for stretching vibrations of the CH 2 groups increases substantially.

We have used the absorption spectra of whole blood, erythrocytes, and plasma to study photochemical reactions initiated by exposure of blood in vivo to UV radiation (UV irradiation) in the UV-visible and IR regions of the spectrum. We have established that when blood is exposed to therapeutic doses of UV radiation (0.5 J/cm 2 ), the absorption of blood proteins decreases as monitored using the UV absorption and luminescence bands of the proteins; photochemical reactions are initiated in the protein and heme components of the hemoglobin. For the studied doses, the reversible reaction of photodissociation of hemoglobin complexes with oxygen is one of the most likely primary reactions initiated by UV irradiation of blood. We conclude that changes in the position and relative intensities of the IR absorption bands of the peptide groups (stretching and bending vibrations of NH, CN, and CO bonds) may be due to conformational transitions in the blood protein macromolecules, induced with a change in the intermolecular hydrogen bonds on absorption of the UV radiation by the blood. The changes in the absorption spectra of blood initiated by UV irradiation are compared with the results of laboratory blood analyses.Key words: UV irradiation, spectrum of blood, photodissociation of hemoglobin, conformational transitions in proteins. Introduction.Exposure of blood to UV radiation (UV irradiation) is widely used in medical practice for treatment of various diseases as a method based on modification of blood by optical radiation in the UV range followed by returning the blood back into the body. UV irradiation is recognized as an effective phototherapy method that has multiple impacts on the body [1, 2]. However, to date opinions vary concerning the primary mechanisms of action on the blood by UV irradiation. The effect of UV irradiation has been studied in the most detail in cell cultures, for which several important effects have been identified: the high reversibility of the changes induced by UV irradiation; the different sensitivities of both different cells and the same cell, depending on its physiological state; stimulation of protein and nucleic acid synthesis by exposure to small UV doses [3].The effect of UV irradiation at the molecular level has been most studied for exposure of cell cultures and biomolecules to high doses (D UV >> 1 J/cm 2 ). For such doses, the molecular structure of DNA breaks down, intramolecular crosslinking of pyrimidine bases and different types of intermolecular crosslinking appear. The most general primary response of proteins to treatment with high doses of UV irradiation is the process of deamination and decarboxylation [4]. The photodissociation products are NH 3 , CO 2 , and aldehydes. A number of observed effects are associated with denaturing changes in the protein molecules. Among the effects detected at the molecular level, we also note changes in the biological activity of proteins and formation of new compounds having higher biological activity. Some of these compounds, structurally...

We used IR Fourier absorption spectra of blood to study changes in the structure of globular blood proteins with extracorporeal autohemomagnetotherapy, used to treat ischemic heart disease. We compare the spectra of blood before and after magnetotherapy in the regions: amide I (1655 cm -1 ), amide II (1545 cm -1 ), amide III (1230-1350 cm -1 ), amide IV and amide V (400-700 cm -1 ). We have shown that pronounced changes in the spectra in the indicated regions on direct exposure of blood in vivo to a low-frequency pulsed magnetic field are connected with conformational changes in the secondary structure of globular blood proteins, which are apparent in the increase in the contribution of the α-helix conformation. We discuss the magnetotherapy-initiated appearance of new IR absorption bands at 1018 and 1038 cm -1 and an increase in the intensity of a number of other bands located in the 1000-1200 cm -1 region, which suggests a change in the concentration of some blood components.

We have used the absorption spectra of whole blood in the UV-visible and IR regions of the spectrum to study changes in the structure of the molecular components of blood when exposed to a low-frequency pulsed magnetic field used to treat ischemic heart disease. We show that pronounced changes in the spectra when the blood is directly exposed in vivo to a magnetic field may be due to breaking of the bond between the heme group and the protein of the hemoglobin, as a consequence of changes in the intermolecular interactions in the polypeptide chains of the hemoglobin and also the spin states of the paramagnetic heme components. Exposure to a magnetic field results in changes in the conformations of the polypeptide chains of hemoglobin and the rate of dissociation of oxyhemoglobin. The structural changes in the hemoglobin molecule are considered as one of the possible primary mechanisms of action on blood in vivo for a low-frequency pulsed magnetic field.Key words: IR absorption spectrum of blood, low-frequency magnetic field, hemoglobin.Introduction. To date, a considerable amount of experimental data has been accumulated on the effect of electromagnetic fields on various biological systems. The major characteristic features of magnetobiological effects have been reliably established [1][2][3]. Further development of magnetobiology is stimulated by the specific practical orientation of magnetobiological effects. On the one hand, medical centers, considering that magnetic fields have diverse therapeutic effects, use electromagnetic radiation for treatment of a wide range of diseases. On the other hand, people are constantly surrounded by natural and anthropogenic magnetic fields, which may pose a threat to human health. However, to date there has been no clear interpretation of the primary mechanisms of action for magnetic fields responsible for transforming the action of the magnetic field in biological systems to a biologically desirable response [2][3][4]. An important scientific problem of fundamental interest is study of the primary mechanisms by physical methods, making it possible to analyze processes at the molecular level that are activated by magnetic fields. Furthermore, a solution to this problem is needed both for further development of physiotherapeutic methods and optimal setting of public health standards, as well as for development of methods for protection from undesirable electromagnetic radiation.Magnetotherapy, as a method based on the effect of magnetic fields on the body for therapeutic and prophylactic purposes, has been successfully used for treatment of ischemic heart disease. Blood is sensitive to exposure to a magnetic field, which can alter coagulation of blood and regional and peripheral hemodynamics and can have a hypotensive effect [5,6].The aim of this work was to use spectral methods to study the mechanisms of the primary physicochemical processes determining the effect of magnetic fields on the molecular structures of blood in vivo. It is specifically the participation of molecule...

Oxygen quenching of excited triplet and singlet states of gas-phase anthracene and its derivatives that have similar energies of the lower triplet levels but widely different oxidation potentials (0.44 < E ox < 1.89 V) was studied. Quenching rate constants for singlet (k S O 2 ) and triplet (k T O 2 ) states in addition to the fraction of oxygen-quenched singlet and triplet states q S 1 (T 1 ) O 2 were determined from the decay rates, fluorescence intensities, and delayed fluorescence as functions of oxygen pressure. It was found that k S O 2 values vary from 2⋅10 4 (9,10-dicyanoanthracene) to 1.2⋅10 7 sec -1 ⋅torr -1 (anthracene, 9-methylanthracene, 2-aminoanthracene) and k S O 2 values from 5⋅10 2 to 1⋅10 5 sec -1 ⋅torr -1 . The k S O 2 values for anthracene, 9-methylanthracene, and 2-aminoanthracene, which have fast rates of interconversion from S 1 to T 1 , are close to the rate constants for gas-kinetic collisions and are independent of the oxidation potentials (E ox ). The quenching rate constants k S O 2 for the other anthracene derivatives and k T O 2 for all studied compounds decrease with increasing free energy of electron transfer ∆G ET , which indicates the important role of charge-transfer interactions in the oxygen quenching of singlet S 1 -and triplet T 1 states.