Long-lived reactive protein products were shown to be evolved under heat treatment and low-intensity laser irradiation in blood serum in presence of dissolved oxygen from the air. These reactive protein products generate hydrogen peroxide for a long time, which results from conjugated electron-radical chain reactions. Long-lived reactive protein species play an important role in the adaptation of living systems to stress factors. Apparently, the formation of visible light- and heat-induced reactive protein species is not specific to just blood serum proteins, rather than it could also be a feature of other proteins.

After injection of 20 mg/kg peroxiredoxin 6 to male Kv:SHK mice 15 min before X-ray irradiation in the range of lethal doses (7–10 Gy), the mice remained alive for 30 days, whereas the mortality of the control animals was 100%. In the irradiated animals, peroxiredoxin 6 decreased the severity of radiation-induced leucopenia, granulocytopenia, and thrombocytopenia, increased the number of blood corpuscles, and prevented the mass death of epithelial cells and the destruction of the small intestine. Thus, peroxiredoxin 6 can be regarded as a prophylactic radioprotective agent.

A process for manufacture of chitosan-based biodegradable biopolymer membranes suitable for medical applications was developed. A technology for inclusion of broad spectrum antibiotics into the chitosan membranes was elaborated. The effects of pH of the solution surrounding the membranes and the initial solvent chosen for chitosan on the kinetics of release of antibiotics from the membranes were studied. It was demonstrated that the kinetics of drug release from the chitosan-based biodegradable biopolymer membranes depends on the properties of substance immobilized in the membrane, the membrane manufacture process, and extraction conditions.

The influence of biologically relevant anions (succinate, acetate, citrate, chloride, bicarbonate, hydroorthophosphate, dihydroorthophosphate, nitrite, nitrate) on the formation of hydrogen peroxide and hydroxyl radicals in water was studied under the effect of non-ionizing radiation: heat, laser light with a wavelength of 632.8 nm, corresponding to the maximum absorption of molecular oxygen, and electromagnetic radiation of extremely high frequencies. It has been established that various anions may both inhibit the formation of reactive oxygen species and increase it. Bicarbonate and sulfate anions included in the biological fluids' and medicinal mineral waters have significant, but opposite effects on reactive oxygen species production. Different molecular mechanisms of reactive oxygen species formation are considered under the action of the investigated physical factors involving these anions, which may influence the biological processes by signal-regulatory manner and provide a healing effect in physical therapy.

It is demonstrated that hydroxyl radicals and hydrogen peroxide are formed under the action of uranyl ions in aqueous solutions containing no reducing agents. In the presence of uranyl ions, formation of 8-oxoguanine in DNA and long-lived protein radicals are observed in vitro. It is shown that the pro-oxidant properties of uranyl at micromolar concentrations mostly result from the physico-chemical nature of the compound rather than its radioactive decay. Uranyl ions lead to damage in DNA and proteins causing death of HEp-2 cells by necrotic pathway. It is revealed that the uranyl ions enhance radiation-induced oxidative stress and significantly increase a death rate of mice exposed to sublethal doses of X-rays.

It has been previously shown that reactive oxygen species (ROS) produce the long-lived reactive protein species (LRPS) as a result of ionizing radiation exposure. Since laser radiation and thermal effects in water solutions also result in ROS generation, this study was aimed to investigate and demonstrate the possibility of LRPS formation from the blood serum proteins – albumin and gamma-globulin – in response to moderate laser radiation and hyperthermia, as well as the production of ROS. Chemiluminescence of BSA and gamma-globulin (GG) in solutions subjected to moderate heating allowed detecting LRPS with a half-life of about 4 h, while enhanced chemiluminescence using the luminol para-iodophenol peroxidase system testified prolonged generation of Н2О2 in BSA and GG solutions. The obtained data indicate the ability of blood serum proteins – albumins and globulins – to form LRPS upon laser radiation and heating. They can act as components of an antioxidant protection system required for inactivation of singlet oxygen, also playing a signaling and regulatory role in the processes related to Н2О2 formation.

Background: Proteins oxidized by the action of X-rays represent long-lived reactive species, which trigger the secondary generation of reactive oxygen species (ROS). A change in the hydrogen peroxide (H2O2) content induced by various physical impacts may be an important factor of the therapeutic effect and the adaptation of the organism to unfavorable environmental conditions. Moderate hyperthermia and a number of physiotherapeutic procedures leading to a local warming of tissues are widely used in medical practice. However, the biological mechanisms of their curative effect are poorly understood. The prolonged generation of H2O2 long-lived reactive protein species (LRPS) after heating may be one of the mechanisms of activation of protective cellular mechanisms and thus to contribute to overcoming the disease. Aim: To investigate if the serum proteins bovine serum albumin (BSA) and bovine gamma-globulin (BGG) can form LRPS under moderate hyperthermia and show that heat induces LRPS, which in turn continuously generate ROS, in particular H2O2. Materials and methods: LRPS were studied by measuring the heat-induced chemiluminescence of protein solutions using a specially elaborated highly sensitive photon-counting chemiluminometer Biotoks-7 AM. The Results: Here we studied the possibility of formation of long-lived species of the blood serum proteins BSA and BGG in air-saturated solutions under the action of heat. It is shown that heat induces the generation of long-lived protein species, which in turn generate ROS (1O2, О2-•, OH•, H2O2). The formation of the long-lived reactive species of BSA and BGG with a half-life of about 4 h induced by moderate hyperthermia was revealed using the chemiluminescence of protein solutions. It was found that long-lived reactive species of BSA and BGG cause prolonged generation of H2O2. Conclusion: Thus, we found a new fundamental property of serum proteins: by the action of moderate heating, they are able to transform into LRPS that produce H2O2 over a long period of time. Therefore, it cannot be excluded that the heat treatment during physiotherapeutic procedures in clinical practice is accompanied by local heating and the formation of LRPS. H2O2 generated by these species may participate in signaling pathways and induce adaptive response in humans.

It is found that in bidistilled water saturated with oxygen, hydrogen peroxide and hydroxyl radicals are formed under the influence of visible and infrared radiation in the absorption bands of molecular oxygen. Formation of reactive oxygen species (ROS) occurs under the influence of both solar and artificial light sources, including the coherent laser irradiation. The oxygen effect, i.e. the impact of dissolved oxygen concentration on production of hydrogen peroxide induced by light, is detected. It is shown that the visible and infrared radiation in the absorption bands of molecular oxygen leads to the formation of 8-oxoguanine in DNA in vitro. Physicochemical mechanisms of ROS formation in water when exposed to visible and infrared light are studied, and the involvement of singlet oxygen and superoxide anion radicals in this process is shown.

Formation of long-lived radicals in solutions of casein and its hydrolysate with an equimolar mixture of amino acids was compared by measuring the X-ray-induced chemiluminescence. It was shown that free amino acids constituting the protein produce long-lived radicals. It was demonstrated that some amino acids (Leu, Ile, Val, Ser, Trp, Met, Pro, Arg, Gly, Phe) emit light of visible spectrum over a long period of time after irradiation, which indicates generation of long-lived radicals of these amino acids. The half-life times of these radicals are several hours. Dissolution of irradiated dry amino acids capable of luminescing over a long time causes formation of hydrogen peroxide in the aqueous medium.