Influence of a Single Deuterium Substitution for Protium on the Frequency Generation of Different-Size Bubbles in IFNA17.

The influence of a single 2H/1H replacement on the frequency generation of different-size bubbles in the human interferon alpha-17 gene (IFNA17) under various energies was studied by a developed algorithm and mathematical modeling without simplifications or averaging. This new approach showed the efficacy of researching DNA bubbles and open states both when all hydrogen bonds in nitrogenous base pairs are protium and after an 2H-substitution. After a single deuterium substitution under specific energies, it was demonstrated that the non-coding region of IFNA17 had a more significant regulatory role in bubble generation in the whole gene than the promoter had. It was revealed that a single deuterium substitution for protium has an influence on the frequency generation of DNA bubbles, which also depends on their size and is always higher for the smaller bubbles under the largest number of the studied energies. Wherein, compared to the natural condition under the same critical value of energy, the bigger raises of the bubble frequency occurrence (maximums) were found for 11-30 base pair (bp) bubbles (higher by 319%), 2-4 bp bubbles (higher by 300%), and 31 bp and over ones (higher by 220%); whereas the most significant reductions of the indicators (minimums) were observed for 11-30 bp bubbles (lower by 43%) and bubbles size over 30 bp (lower by 82%). In this study, we also analyzed the impact of several circumstances on the AT/GC ratio in the formation of DNA bubbles, both under natural conditions and after a single hydrogen isotope exchange. Moreover, based on the obtained data, substantial positive and inverse correlations were revealed between the AT/GC ratio and some factors (energy values, size of DNA bubbles). So, this modeling and variant of the modified algorithm, adapted for researching DNA bubbles, can be useful to study the regulation of replication and transcription in the genes under different isotopic substitutions in the nucleobases.

Influence of Single Deuterium Replacement on Frequency of Hydrogen Bond Dissociation in IFNA17 under the Highest Critical Energy Range.

The effect of single substitutions of protium for deuterium in hydrogen bonds between pairs of nitrogenous bases on the open states occurrence probability at high critical breaking energies of these bonds has been studied. The study was carried out using numerical methods based on the angular mathematical model of DNA. The IFNA17 gene was divided into three approximately equal parts. A comparison of the open states occurrence probability in these parts of the gene was done. To improve the accuracy of the results, a special data processing algorithm was developed. The developed methods have shown their suitability for taking into account the occurrence of open states in the entire range of high critical energies. It has been established that single 2H/1H substitutions in certain nitrogenous bases can be a mechanism for maintaining the vital activity of IFNA17 under critical conditions. In general, the developed method of the mathematical modeling provide unprecedented insight into the DNA behavior under the highest critical energy range, which greatly expands scientific understanding of nucleobases interaction.

Evaluation of effectiveness of a new treatment method for healing infected wounds: an animal model.

OBJECTIVE: To evaluate the effectiveness of a new treatment method in healing superficial infected wounds compared with surgical debridement with chlorhexidine solution. METHOD: In this animal model, two wounds were created on the back of 10 male adult rabbits. Wounds treated by Method 1 were debrided using 0.02% chlorhexidine aqueous solution and an antibiotic topical ointment. Wounds treated by Method 2 wounds were treated using a newly developed device which enabled visual monitoring of the wound as it was treated with various pharmacological solutions (including antiseptic, antiseptic oxidant and an osmotically active agent) specifically formulated for each wound healing stage. Wound area size (using digital planimetry) and time taken to clean the wound were recorded, and biopsies were taken, at the beginning of the study and at various timepoints throughout. RESULT: It was observed that both wound cleaning and wound healing were accelerated by treatment with method 2 compared with method 1 (by 43.8% and 36.7%, respectively). There were also a significantly smaller number of complications in these wounds [p=0.0044] due to the positive ratios of neutrophils and fibroblasts in the wound cavities (from the third to the fourteenth day after wound modelling). CONCLUSION: Wounds treated with the new device in method 2 had a shorter wound healing time than wounds treated with a traditional method. The automated influx-outflow of solutions removed any fragments of necrotic tissue from the wound surface. Wounds were able to be monitored without the need to remove dressings. The transparent, airtight film, which allowed for wound monitoring without the need to remove dressings, meant that suturing was not required. This resulted in no complications in the wounds treated by this new method.

DNA Dynamics under Periodic Force Effects.

The sensitivity of DNA to electromagnetic radiation in different ranges differs depending on various factors. The aim of this study was to examine the molecular dynamics of DNA under the influence of external periodic influences with different frequencies. In the present paper, within the framework of a mechanical model without simplifications, we investigated the effect of various frequencies of external periodic action in the range from 1011 s-1 to 108 s-1 on the dynamics of a DNA molecule. It was shown that under the influence of an external periodic force, a DNA molecule can perform oscillatory movements with a specific frequency characteristic of this molecule, which differs from the frequency of the external influence ω. It was found that the frequency of such specific vibrations of a DNA molecule depends on the sequence of nucleotides. Using the developed mathematical model describing the rotational motion of the nitrogenous bases around the sugar-phosphate chain, it is possible to calculate the frequency and amplitude of the oscillations of an individual DNA area. Such calculations can find application in the field of molecular nanotechnology.

Reduction of Deuterium Level Supports Resistance of Neurons to Glucose Deprivation and Hypoxia: Study in Cultures of Neurons and on Animals.

The effect of a reduced deuterium (D) content in the incubation medium on the survival of cultured neurons in vitro and under glucose deprivation was studied. In addition, we studied the effect of a decrease in the deuterium content in the rat brain on oxidative processes in the nervous tissue, its antioxidant protection, and training of rats in the T-shaped maze test under hypoxic conditions. For experiments with cultures of neurons, 7-8-day cultures of cerebellar neurons were used. Determination of the rate of neuronal death in cultures was carried out using propidium iodide. Acute hypoxia with hypercapnia was simulated in rats by placing them in sealed vessels with a capacity of 1 L. The effect on oxidative processes in brain tissues was assessed by changes in the level of free radical oxidation and malondialdehyde. The effect on the antioxidant system of the brain was assessed by the activity of catalase. The study in the T-maze was carried out in accordance with the generally accepted methodology, the skill of alternating right-sided and left-sided loops on positive reinforcement was developed. This work has shown that a decrease in the deuterium content in the incubation medium to a level of -357‱ has a neuroprotective effect, increasing the survival rate of cultured neurons under glucose deprivation. When exposed to hypoxia, a preliminary decrease in the deuterium content in the rat brain to -261‱ prevents the development of oxidative stress in their nervous tissue and preserves the learning ability of animals in the T-shaped maze test at the level of the control group. A similar protective effect during the modification of the 2H/1H internal environment of the body by the consumption of DDW can potentially be used for the prevention of pathological conditions associated with the development of oxidative stress with damage to the central nervous system.

Electrophysiological Activity and Survival Rate of Rats Nervous Tissue Cells Depends on D/H Isotopic Composition of Medium.

The deuterium content modification in an organism has a neuroprotective effect during the hypoxia model, affecting anxiety, memory and stress resistance. The aim of this work was to elucidate the possible mechanisms of the medium D/H composition modification on nerve cells. We studied the effect of an incubation medium with a 50 ppm deuterium content compared to a medium with 150 ppm on: (1) the activity of Wistar rats' hippocampus CA1 field neurons, (2) the level of cultured cerebellar neuron death during glucose deprivation and temperature stress, (3) mitochondrial membrane potential (MMP) and the generation of reactive oxygen species in cultures of cerebellar neurons. The results of the analysis showed that the incubation of hippocampal sections in a medium with a 50 ppm deuterium reduced the amplitude of the pop-spike. The restoration of neuron activity was observed when sections were returned to the incubation medium with a 150 ppm deuterium content. An environment with a 50 ppm deuterium did not significantly affect the level of reactive oxygen species in neuron cultures, while MMP decreased by 16-20%. In experiments with glucose deprivation and temperature stress, the medium with 50 ppm increased the death of neurons. Thus, a short exposure of nerve cells in the medium with 50 ppm deuterium acts as an additional stressful factor, which is possibly associated with the violation of the cell energy balance. The decrease in the mitochondrial membrane potential, which is known to be associated with ATP synthesis, indicates that this effect may be associated with the cell energy imbalance. The decrease in the activity of the CA1 field hippocampal neurons may reflect reversible adaptive changes in the operation of fast-reacting ion channels.

Inequality in the Frequency of the Open States Occurrence Depends on Single 2H/1H Replacement in DNA.

In the present study, the effect of 2H/1H isotopic exchange in hydrogen bonds between nitrogenous base pairs on occurrence and open states zones dynamics is investigated. These processes are studied using mathematical modeling, taking into account the number of open states between base pairs. The calculations of the probability of occurrence of open states in different parts of the gene were done depending on the localization of the deuterium atom. The mathematical modeling study demonstrated significant inequality (dependent on single 2H/1H replacement in DNA) among three parts of the gene similar in length of the frequency of occurrence of the open states. In this paper, the new convenient approach of the analysis of the abnormal frequency of open states in different parts of the gene encoding interferon alpha 17 was presented, which took into account both rising and decreasing of them that allowed to make a prediction of the functional instability of the specific DNA regions. One advantage of the new algorithm is diminishing the number of both false positive and false negative results in data filtered by this approach compared to the pure fractile methods, such as deciles or quartiles.

8-Oxoguanine-DNA-Glycosylase Gene Polymorphism and the Effects of an Alternating Magnetic Field on the Sensitivity of Peripheral Blood.

BACKGROUND: The production of reactive oxygen species (ROS) in animals and cells often results from exposure to low-intensity factors, including magnetic fields. Much of the discussion about the initiation of oxidative stress and the role of ROS and radicals in the effects of magnetic fields has centered on radical-induced DNA damage. METHODS: The DNA concentration in the final solution was determined spectrophotometrically. Typing of the polymorphic variant rs1052133 of the 8-oxoguanin DNA glycosylase (hOGG1) gene was performed by polymerase chain reaction. An enzyme immunoassay was performed to determine the level of 8-oxyguanine in DNA. To process samples exposed to an alternating magnetic field, the authors developed a device for the automated study of biological fluids in an alternating magnetic field. The content of hydrogen peroxide in aqueous solutions of DNA was determined using the spectrophotometric method. RESULTS: It was experimentally determined that an increase in the concentration of hydrogen peroxide in an aqueous medium by 3-5 times under the action of a low-frequency magnetic field reduces the resistance of the genomic material to oxidative modification and the accumulation of 8-oxyguanine in DNA. A model is proposed for the mechanism of action of a low-frequency magnetic field on aqueous solutions of nucleic acids and proteins, which satisfies the model of a chemical oscillator for the transformations of reactive oxygen species in an aqueous medium. The model illustrates the oscillating nature of the processes occurring in an aqueous solution of DNA and makes it possible to predict changes in the concentration of hydrogen peroxide in an aqueous solution of biopolymers, depending on the frequency of the acting low-intensity magnetic field. CONCLUSIONS: The key element in the mechanisms involved in the effects of low-intensity magnetic field on living systems is the occurrence of ROS generation in the aquatic environment of chemical oscillators, in which the competition of physical and chemical processes (electron transfers, reactions of decay and addition of radicals, spin magnetically induced conversion, synthesis, and decay of the longest-lived form-hydrogen peroxide) is controlled by a magnetic field.

Changes in Number and Antibacterial Activity of Silver Nanoparticles on the Surface of Suture Materials during Cyclic Freezing.

This article presents the results of the 10-fold cyclic freezing (-37.0 °C) and thawing (0.0 °C) effect on the number and size range of silver nanoparticles (AgNPs). AgNPs were obtained by the cavitation-diffusion photochemical reduction method and their sorption on the fiber surface of various suture materials, perlon, silk, and catgut, was studied. The distribution of nanoparticles of different diameters before and after the application of the cyclic freezing/thawing processes for each type of fibers studied was determined using electron microscopy. In general, the present study demonstrates the effectiveness of using the technique of 10-fold cyclic freezing. It is applicable to increase the absolute amount of AgNPs on the surface of the suture material with a simultaneous decrease in the size dispersion. It was also found that the application of the developed technique leads to the overwhelming predominance of nanoparticles with 1 to 15 nm diameter on all the investigated fibers. In addition, it was shown that after the application of the freeze/thaw method, the antibacterial activity of silk and catgut suture materials with AgNPs was significantly higher than before their treatment by cyclic freezing.