Shift In Balance Research Articles

Heart rate variability in patients with obstructive sleep apnea and comorbid pathology

Aim. To study the features of heart rate variability in patients with obstructive sleep apnea (OSA) and comorbid pathology.Materials and methods. Polysomnography and registration of heart rate variability (HRV) were performed in 98 patients who applied to a neurologist.Results. Most of the HRV indicators in patients with OSA were significantly lower compared to the control group with orthostatic loading. The most notable of these were: TP (ms2), SDNN (ms), CV (%), HF (ms2), RMSSD (ms), DX (ms), LF (ms2). There were higher CI at rest (3.29 (1.53; 6.10), p = 0.034) and IVR (455.45 (286.95; 704.87), p = 0.014) during exercise in patients with OSA in comparison with the control group (1.73 (0.79; 3.93) and 344.00 (171.57; 440.87), respectively). It was found that arterial hypertension (94.6 %), chronic cerebral ischemia (80.4 %), and acute cerebrovascular accident (10.7 %) were significantly more common in patients with OSA than those examined without apnea (71.4 %, 42.9 % and 0.0 % respectively).Conclusions. BMI, neck volume, saturation level, and desaturation index can be considered as criteria for referring patients for HRV registration in order to assess the state of adaptive reserves. In patients with OSA, according to HRV indicators, a shift in the autonomic balance was found, which is expressed by a weakening of vagal influences and the degree of participation of the autonomic circuit in the regulation of heart rate with an increase in sympathetic orientation and central control mechanisms, a decrease in the body's adaptive resources. Work should be continued to clarify the contribution of comorbid pathology in patients with OSA to the development of autonomic dysfunction.

The Dynamics of an Entangled Security Dilemma: China's Changing Nuclear Posture

Abstract Amid an intensifying rivalry with the United States, China is modernizing and significantly expanding its nuclear forces. These developments fuel concerns that China's traditional nuclear strategy premised on a limited nuclear arsenal for assured retaliation and a no-first-use policy is undergoing a major shift. Using Chinese-language materials, an examination of Chinese debates about China's security environment and the future direction of its nuclear strategy finds that a nuclear-conventional entangled security dilemma is emerging between the United States and China. The shift in the conventional balance of force in the region and the U.S. development of lower-yield nuclear weapons has led to greater fears in China of U.S. limited nuclear use in a conflict. Chinese strategists increasingly believe that U.S. nonnuclear strategic capabilities threaten China's nuclear forces. Although there is limited evidence of a shift in its nuclear strategy, China is changing its strategic posture to ensure its second-strike capability, including by relying on advanced conventional weapons (e.g., counterspace capabilities, cyber weapons, and electronic warfare) that can target U.S. missile defense. The dynamics of an entangled security dilemma may weaken arms race stability, and they underscore why it will be challenging for the United States to engage China in nuclear arms control.

Immunomorphological aspects of post-traumatic subatrophy of the eyeball

The study attempts to characterize immunomorphological disorders at different degrees of post-traumatic subatrophy of the eyeball. The study included 123 patients with blind and unpromising eyes, eyeball subatrophy of various degrees, who were divided into three groups (1, 2 and 3) depending on the degree of eyeball subatrophy. The greatest risk of autoimmune inflammation was observed in patients with degree I subatrophy. Contusion injury of the eye was proven to not exclude the course of post-traumatic autoimmune uveitis. The development of post-traumatic subatrophic process is associated with activation of systemic organ-specific immunity, shift of balance in main regulatory subpopulations. The study showed that the most severe clinical course of chronic post-traumatic uveitis is observed in patients as a result of penetrating trauma to the eyeball. The contusion nature of such ocular injury does not exclude the development of autoimmune inflammation.

Morphofunctional characteristics of proliferation and apoptosis of germinal epithelium: pathogenesis of temporary azoospermia after local electron irradiation.

At present, the violation of male reproductive function caused by electron irradiation, leading to a decrease in the proliferative activity of germ cells, as well as the development of methods for its correction are relevant. The effect of leukocyte-poor platelet-rich plasma (LP-PRP) growth factors, which have a high regenerative capacity for the restoration of spermatogenesis, remains poorly understood. Objective of the study: immunohistochemical (IHC) assessment of the proliferation of germinal epithelium after electron irradiation with a dose of 2 Gy. Wistar rats (n=60) were divided into groups (conventional names): (I) control (n=30), which were injected with saline; (II) single local irradiation of the testes with electrons at a dose of 2 Gy (n=30). Animals were gradually withdrawn from the experiment over 11 weeks: 5 animals one week after irradiation, and then 5 animals once every 2 weeks. The testes were studied by histological and IHC methods using antibodies to Ki-67, Bcl-2, and p53. Terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) method was used to study DNA fragmentation in germ cells, which were stained with TdT solution (Thermo Fisher, USA) and incubated for 60 minutes. The nuclei were counterstained with 4',6-diamidino-2-phenylindole (DAPI) (blue spectrum) (Thermo Fisher), and the luminescence intensity was controlled in a fluorescent microscope with a set of fluorescein isothiocyanate (FITC) filters (green spectrum). IHC analysis of testes after irradiation showed a shift in the proliferative-apoptotic balance towards apoptosis of germ cells: a decrease in the expression levels of Ki-67 (16.3%±1.1%, P<0.05) and Bcl-2 (9.1%±1.1%, P<0.05), an increase in p53-positive cells (74.8%±1.2%, P<0.05) by the end of the experiment. In the experimental model, local irradiation of the testes with electrons at a dose of 2 Gy causes the development of focal hypospermatogenesis, affecting up to 1/8 of the sections of the tubules (in the first week) with a subsequent increase to 1/4 (in the second month), with a tendency to recovery in the third month (temporary azoospermia). The basis of focal hypospermatogenesis is the irradiation-induced proliferative-apoptotic imbalance towards the dominance of apoptosis, which is most pronounced in the pool of spermatogonia.

Immunohistochemical and histochemical analysis of the rat skin after local electron irradiation.

Skin cancer is the most frequently diagnosed type of cancer among all malignant neoplasms. The decrease in mitotic activity and the death of intact keratinocytes arise due to the constantly renewing epithelium being highly sensitive to ionizing radiation. The aim of the study is immunohistochemical evaluation of the proliferative-apoptotic balance of keratinocytes, the fibrous component of the skin, and the expression of pro-inflammatory and anti-inflammatory cytokines after single or fractional local electron irradiation. Wistar rats (n = 80) were taken from the ITM&B Vivarium (Sechenov University) and divided into groups: I-control, which were injected with saline; and experimental groups, local electron irradiation at doses: II-8 Gy (single), III-40 Gy (single), IV-summary dose 78 Gy (fractional; 13 Gy per day for 6 days). We performed histological analysis, histochemical analysis using Masson, safranine, and picrosirius red staining, immunohistochemical (Ki-67, caspase-3, p53, types I and III collagens, IL-1, IL-6, IL-4, and IL-10) and morphometric analysis of skin fragments of the outer surface of the thigh, irradiated in accordance with the design of the experiment. The early and delayed effects of local electron irradiation at different doses were studied. After local electron irradiation, dose-dependent morphological changes in the skin of the experimental groups were observed: violation of the histoarchitectonics of the skin confirmed by morphological and morphometric analysis, the proliferation of connective tissue according to the results of histochemical and immunohistochemical studies with signs of the radiation-induced skin fibrosis development, an increase in the levels of pro- and anti-inflammatory cytokines. We observed the most pronounced signs of radiation-induced skin damage in the group of fractional irradiation after 3 months. 8 Gy and 40 Gy single local electron irradiation leads to a shift in the proliferative-apoptotic balance of keratinocytes toward their apoptosis, which activity is directly correlated with the dose of ionizing radiation, and 78 Gy in fractions leads to partial desquamation of the epithelium and inflammatory infiltration. In addition, after 3 months a significant increase in the expression of type I and III collagen fibers and the development of radiation-induced skin fibrosis takes place against the background of 78 Gy fractional local electron irradiation.

ПОКАЗНИКИ СИСТЕМИ АНТИОКСИДАНТНОГО ЗАХИСТУ У ПЛАЗМІ КРОВІ ХВОРИХ НА ОСТЕОАРТРИТ ПІСЛЯ SARS-CoV-2-ІНФЕКЦІЇ

An outbreak of pneumonia that began in December 2019 in Wuhan (China) caused the spread of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). After an increase in the number of positive cases of infection in China, on January 30, 2020, the World Health Organization declared the virus epidemic a public health emergency. The 2019 coronavirus disease (Coronavirus disease 2019, COVID-19) has a devastating effect on the health of people in many countries around the world. It is known that the SARS-CoV-2 virus, in addition to damaging the lung parenchyma, can damage other organ systems and complicate the condition of patients with comorbid diseases, in particular, with osteoarthritis. Oxidative stress plays an important role in the formation and progression of osteoarthritis. Its development is associated with a violation of the oxidative-antioxidant balance. The aim of the work was to determine the indicators of the antioxidant system in the blood plasma of patients with OA after SARS-CoV-2 infection. All study participants were further divided into three experimental groups: Group I – conditionally healthy people, Group II – patients with OA of the knee joints of the II-III degree, and Group III – patients with OA of the knee joints of the II–III degree who suffered a mild or moderately severe form COVID-19 6–9 months ago. Superoxide dismutase and catalase activity and the content of sulfhydryl groups were determined by generally accepted biochemical methods. Processing of research results was carried out using generally accepted methods of variational statistics. It was found that the activity of anti-radical enzymes (superoxide dismutase and catalase) and the content of compounds containing SH-groups (of protein and non-protein nature) are reduced in the blood plasma of osteoarthritis patients who contracted COVID-19. The obtained results indicate a shift of the oxidant-antioxidant balance in the pro-oxidant direction. These disorders are more profound compared to patients with osteoarthritis who did not suffer from coronavirus infection. The results obtained by us indicate that patients with osteoarthritis may experience a more severe course of osteoarthritis and develop complications after infection with COVID-19.

Інвестування нафтогазовидобутку в ТНК: тенденції, еколого-економічні проблеми та пріоритети

It is substantiated that the intensification of the global environment protection movement in recent decades, the key component of which is the development of tools for transferring national economies to a model of low-carbon development, has had a decisive impact on the dynamics of investment in projects for the development of natural resource potential, primarily hydrocarbons. It has been found that the reduction of dependence of individual countries of the world on oil and natural gas directly depends on the diversification of energy sources to meet the needs of socioeconomic development through the development of the industry for the production of energy from renewable sources. It is proved that the decrease in the volume of production of hydrocarbons and energy carriers produced on its basis is an important factor in the transition of national economies to the model of low-carbon development, in particular, reducing the negative impact on climate processes. It is found that in the sector of «hydrocarbon» TNCs (BP, Shell and Chevron) during 2011–2022 there was a generally downward trend in the dynamics of investments in oil and natural gas production, which has led to significant conjunctural fluctuations in the global markets of hydrocarbons and to structural shifts in the energy balance of many countries of the world. It has been found that BP, Shell and Chevron, along with investing in oil and gas production, finance projects related to the production of energy from alternative sources, which has led to a reduction in capital injections into fossil fuel production and diversified the investment portfolio of these companies, minimizing the risks of reducing their capitalization in the context of diversification of the range of energy carriers in the global and national energy markets. It is proved that the decrease in the volume of investment in oil and gas production in the sector of «hydrocarbon» TNCs (BP, Shell and Chevron) has led to a reformatting of the global energy landscape and created additional prerequisites for increasing the amount of funding for alternative energy projects and solving a set of ecological and economic problems associated with the transition to a low-carbon development model.

Влияние коронавирусной инфекции на маркеры эндотелиальной дисфункции у детей при патологии почек

Coronavirus infection (COVID-19), caused by severe acute respiratory syndrome 2 (SARS-CoV-2) RNA virus, has become a global problem in the world. Its consequences are of great importance for the health status of both adults and children, since the number of lethal outcomes and life-threatening complications has reached high rates. Of particular importance is coronavirus damage of important organs in childhood, due to the possible impairment of their functions and the development of later distant complications. Thus, the formation of acute kidney injury (AKI) in children is an independent risk factor for hospital mortality and disability. An important role in the development of this pathological condition is given to the development of endothelial dysfunction due to the activation of a number of pro-inflammatory cytokines and other biomarkers of endothelial disorders. Endothelitis, endothelial injury, endothelial cell dysfunction, and impaired microcirculatory function in various vascular beds all contribute markedly to life-threatening complications of COVID-19 such as venous thromboembolism and multiple organ failure. Endothelial dysfunction is the main determinant of microvascular disorders due to a shift in vascular balance towards greater vasoconstriction and subsequent organ ischemia, inflammation with concomitant tissue edema and procoagulant condition. In general, understanding the mechanisms of endothelial activation and dysfunction during COVID-19 infection can contribute to early detection of individuals, especially children, at risk of severe complications. Further study of endothelial dysfunction in the pathogenesis of AKI in children with COVID-19 is promising to determine a personalized approach to the management of pediatric patients with COVID-19.

СРЕДНЕСРОЧНОЕ ПРОГНОЗИРОВАНИЕ СКОРОСТИ ПРОСТОЙ ЗРИТЕЛЬНО-МОТОРНОЙ РЕАКЦИИ ПО ПАРАМЕТРАМ АРТЕРИАЛЬНОГО ДАВЛЕНИЯ И ВАРИАБЕЛЬНОСТИ СЕРДЕЧНОГО РИТМА

One of the symptoms of asthenia in space flight is a decrement of cognitive efficiency, memory and concentration. A demand exists for simple noninvasive methods to forecast appearance of cognitive shifts. It is hypothesized that blood pressure (BP) and heart rate variability (HRV) measured in the morning can predict the psychomotor reactions as at the time of measurement, so in the course of the day (medium-term prediction). The investigation involved 6 volunteers (29-44 y.o.) for a 120-day isolation study. The protocol included 5-min ECG and BP measurement soon after awakening, and HRV evaluation. The classic simple ocular-motor reaction (SOMR) test was performed before and then after midday. Regression analysis of reaction duration and stability showed that SOMR time correlated with the homeostatic parameters (BP, HR); stability of SOCM duration correlated both BP and HR, and parameters reflecting HR regulation processes. Elevated diastolic BP correlated with an increase of reaction duration irrespective of whether the test was performed before or in midday. Elevation of diastolic BP and autonomic balance shift toward the sympathetic activity in the morning correlated with a loss in SOMR stability no matter when the test was performed.

FEATURES OF OXIDATIVE METABOLISM AND GENETIC DISORDERS IN PERIPHERAL BLOOD LYMPHOCYTES OF PATIENTS WITH PRIMARY CERVICAL CANCER.

Thecombination of chemo- and radiotherapy used as main treatment of locally advanced cervical cancer (CC) may lead to side effects in healthy cells, which undermine theeffectiveness of treatment and quality of life. Theassessment of damage level in healthy radiosensitive cells from thetumor environment before thetreatment is important in order to predict and prevent remote side effects of radiation. To study theoxidative metabolism and genetic disorders in peripheral blood lymphocytes (PBL) of primary CC patients in order to evaluate thepossibilities of predicting radiation complications based on themolecular and biological properties of PBL. Peripheral blood samples were collected from 13primary CC patients T1-4N0-1M0-1, and PBL were routinely isolated. Theoxidative metabolism (mitochondrial trans-membrane potential, superoxide anion radical (О2•) generation, reactive oxygen species (ROS) production in PBL as well as thelevel of SH-groups in plasma and pro/antioxidant ratio in hemolysates were examined. Thedevelopment of genetic instability was determined by estimation of DNA double-strand breaks (DNA-DSB), frequency and spectrum of chromosome aberrations and apoptosis. Themarked increase in theintensity of О2• generation in PBL (1.5-fold), depletion of SH-groups content (1.6-fold) and a shift in thepro-antioxidant balance (1.4-fold) towards its prooxidant component were observed in theblood of primary CC patients as compared to healthy individuals. These oxidative stress related events were accompanied by an increase in thelevel of DNA-DSB (2.1-fold), apoptosis (3.5-fold) and frequency of cells with chromosome aberrations (3.9-fold). On thecontrary, significant decrease in mitochondrial trans-membrane potential (2.0-fold) and ROS generation in PBL (4.0-fold) were detected. Preliminary data indicate a violation of redox processes regulation, a shift in thepro-antioxidant balance towards its pro-oxidant component, accompanied by an increase in thelevel of DNA damage, development of genetic instability and apoptotic death of blood lymphocytes in primary CC patients.

Discovery of endogenous nitroxyl as a new redox player in Arabidopsis thaliana

Nitroxyl (HNO) is the one-electron reduced and protonated congener of nitric oxide (•NO), owning a distinct chemical profile. Based on real-time detection, we demonstrate that HNO is endogenously formed in Arabidopsis. Senescence and hypoxia induce shifts in the redox balance, triggering HNO decay or formation mediated by non-enzymatic •NO/HNO interconversion with cellular reductants. The stimuli-dependent HNO generation supports or competes with •NO signalling, depending on the local redox environment.

Changes in mucosal immunity of oral cavity upon tooth loss in patients with periodontal diseases

Partial or complete loss of teeth occurs in elderly and senile people, caused, mainly, by chronic generalized periodontitis. At the same time, the impact of presence or absence of persisting teeth and periodontium, is practically not covered in the literature as a factor of balance in the oral cavity, including local immunity of the mucous membranes. Our work concerned the changes in local immunity of the oral cavity occuring with the loss of natural teeth. We have observed 45 elderly people who were divided into 3 study groups, i.e., without inflammatory periodontal pathology (1), with periodontitis (2) and with chronic periapical inflammatory processes in the absence of periodontal inflammation (3). In order to sanitize oral cavity before the upcoming dental prosthetics, the patients of study groups 2 and 3 underwent extraction of all teeth in the upper and lower jaws. Indices of local immunity of the oral cavity in the salivary fluid of patients were assessed before surgical sanitation of the oral cavity (before the teeth extraction) and 30-35 days after removal of the last tooth. We have measured the salivary levels of secretory immunoglobulin A (sIgA) as well as pro-inflammatory cytokines, i.e., interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor- (TNF), and anti-inflammatory cytokines, e.g., receptor antagonist of interleukin-1 (RAIL), interleukin-4 (IL-4), interleukin-10 (IL-10)), as well as contents of antimicrobial peptides in saliva (catelicidin LL-37 and alphadefensins 1-3 (HNP1-3). We have found that the development of inflammation in severe inflammatory periodontal diseases, in particular, chronic generalized periodontitis requiring tooth extraction for oral cavity sanitation is characterized by functional insufficiency of secretory immunity of the oral mucosa associated with decreased secretion of secretory immunoglobulin A and antimicrobial peptides of neutrophilic origin, as well as a shift in the salivary cytokine balance towards increased production of pro-inflammatory cytokines. Removal of teeth, as the main source of inflammation and the basis for maintenance of dysbiotic microbiome biofilm leads to elimination of inflammation and the restoration of immune balance in the oral cavity.

HEART RATE VARIABILITY AND BASIC HEMODYNAMIC PARAMETERS IN MEDICAL STUDENTS IN SEASONS WITH DIFFERENT PHOTOPERIOD

One of the main external factors that contributes to the seasonal functional reorganization of the organism in the process of adaptation is seasonal photoperiodic variability. Day length is affecting not only visual function, but also all physiological and behavioural processes controlled by the circadian rhythm system. The person's ability to adapt to changes in external factors is especially important for medical students who experience significant mental overload in the process of studying at a university. The study goal was to investigate the features of the main hemodynamic parameters and heart rate variability in medical students in the spring and autumn periods, with taking into account gender differences. Materials and methods: A cross-sectional study of 304 students of the North-Ossetian State Medical Academy (Russia) comprising 233 female and 71 male subjects was performed during periods of elongation (spring) and shortening (autumn) of the photoperiod. Blood pressure (BP), pulse rate (HR), parameters of heart rate variability (HRV) were measured. Results: The students showed an increase in DBP and MBP rates within the normal range in autumn. Hemodynamic parameters of SBP, DBP, PBP, MBP in males were significantly higher than in females group, regardless of the season. Interseasonal differences in HRV parameters (LF, THF, PHF, PLF, LF/HF, IC) were revealed. From spring to autumn period, LF decreases from 980.22 (590.30; 1445.83) to 690.68 (438.81; 1170.15) ms2 against the background of a decrease in the dominant period of the high-frequency component of the spectrum (THF) from 5.40 (3 .77; 6.10) to 3.71 (3.08; 5.54) s. The contribution of the high-frequency component (PHF) to the total power of HRV fluctuations increases by 10.4%, and the low-frequency component (PLF) decreases by 6.45% as the photoperiod shortens. The centralization index (IC) also declines from 2.58 (1.42; 3.90) to 1.61 (0.97; 2.98); p=0.0076. Parameters of Mean, Mo, RMSSD, pNN50, SDNN, TP, HF, PHF in spring are lower in males in comparison with females, while parameters of HR, SI, PLF, LF/HF, VLF/HF, IC, PARS are higher in males. Conclusions: It was indicated that the change in the photoperiod trend is an important mediator of heart rate variability in the annual cycle. The lengthening of the photoperiod in the spring season is accompanied by a shift in the vegetative balance of students towards an increase in the tonus of the sympathetic division of the autonomic nervous system (ANS) together with the involvement of the central circuit of the heart rhythm regulation. In autumn, on the background of shorter daylight duration hours, parasympathetic influences are intensified and autonomic regulation circuit is most active. In the common trend of increased sympathetic activity of the ANS and activation of the central regulatory circuit in the spring, in young males these changes are indicated at greater extent.

Interaction Of Inflammatory Parameters And Thiol/Disulfide System Of Antioxidant Protection In Chronic Obstructive Pulmonary Disease

Introduction — Increased incidence and prevalence of chronic obstructive pulmonary disease (COPD) provides rationale for describing the disease progression mechanism, considering the interaction of key participants of this process. The objective of our study was to establish the dysfunction parameters of thiol/disulfide system components and adaptive immunity unit in patients with stable chronic obstructive pulmonary disease (COPD). Material and Methods — We examined patients with stable COPD of moderate (62 subjects) or severe (50 subjects) grades. The control group included 32 subjects. Prooxidant and antioxidant markers of oxidative stress were investigated with ELISA. We determined cytokine levels in blood plasma and the number of T helper cells expressing IL-6R with flow cytometry (BD FACSCanto II, USA). Correlation pleiads sensu Terentiev were employed to visualize the data. Results — Changes in both antioxidant and cytokine status of subjects with COPD of varying severity grades implied the progression of systemic inflammation in conditions of uncontrolled activation of adaptive immunity unit rather than just a shift in the peroxide balance and an increase in oxygen metabolites. Conclusion — Accumulation of biomolecule peroxidation products, imbalance in the prooxidant-antioxidant system, and a change in pathogenetic mechanism of inflammation could lead to an aggravated course of bronchopulmonary pathology.

Neobaicalein Inhibits Th17 Cell Differentiation Resulting in Recovery of Th17/Treg Ratio through Blocking STAT3 Signaling Activation

Huangqin is the dried root of Scutellaria baicalensis Georgi, which has been widely utilized for heat-clearing (Qingre) and dewetting (Zaoshi), heat-killed (Xiehuo) and detoxifying (Jiedu) in the concept of Traditional Chinese Medicine and is used for treating inflammation and cancer in clinical formulas. Neobaicalein (NEO) is of flavonoid isolated from Huangqin and has been reported to possess prominent anti-inflammatory effects in published work. Th17/Treg balance shift to Th17 cells is an essential reason for autoimmune inflammatory diseases. However, the role NEO plays in Th17 and Treg and the underlying mechanism has not been elucidated yet. Network pharmacology-based study revealed that NEO predominantly regulated IL-17 signaling pathway. Moreover, our result shown that NEO (3-30 μmol/L) down-regulated Th17 differentiation and cellular supernatant and intracellular IL-17A level and tumor necrosis factor α production in a concentration-dependent manner. The further mechanism research revealed that NEO also specifically inhibited phosphorylation of STAT3(Tyr725) and STAT4 (Y693) without influence on activation of STAT5 and STAT6 in splenocytes. Immunofluorescence results illuminated that NEO effectively blocked STAT3 translocated into nucleus. Interestingly, NEO at appreciated dose could only inhibit Th17 cell differentiation and have no effect on Treg differentiation. The present study revealed that NEO effectively inhibited Th17 cell differentiation through specifically blocking the activation of STAT3 signaling without inactivation of STAT5 and STAT6. Additional inhibitory effect on activation of STAT4 by NEO also suggested the potential for antagonism against Th1 differentiation. All work suggested that NEO may be a potential candidate for immunoregulation and treating autoimmune inflammatory diseases through inhibiting immune cell viability and T cell differentiation.

Inhibition of thioredoxin reductase activity reduces the antioxidant defense capacity of human pluripotent stem cells under conditions of mild but not severe oxidative stress

Pro-oxidative shift in redox balance, usually termed as “oxidative stress”, can lead to different cell responses depending on its intensity. Excessive accumulation of reactive oxygen species (“oxidative distress”) can cause DNA, lipid and protein damage. Physiological oxidative stimulus (“oxidative eustress”), in turn, can favor cell proliferation and differentiation – the processes of paramount importance primarily for stem cells. Functions of antioxidant enzymes in cells is currently a focus of intense research, however the role of different antioxidant pathways in pluripotent cell responses to oxidative distress/eustress is still under investigation. In this study, we assessed the contribution of the thioredoxin reductase (TrxR)-dependent pathways to maintaining the redox homeostasis in human induced pluripotent stem cells and their differentiated progeny cells under basal conditions and under conditions of oxidative stress of varying intensity. Employing the genetically encoded H2O2 biosensor cyto-HyPer and two inhibitors of thioredoxin reductase (auranofin and Tri-1), we show that the reduced activity of TrxR-dependent enzymatic systems leads to the non-cytotoxic disruption of thiol-disulfide metabolism in the cytoplasm of both pluripotent and differentiated cells under basal conditions. Quantifying the cytoplasmic concentrations of peroxide establishing in H2O2-stressed cells, we demonstrate that TrxR-dependent pathways contribute to the antioxidant activity in the cell cytoplasm under conditions of mild but not severe oxidative stress in both cell lines tested. The observed effects may testify about a conservative role of the TrxR-controlled enzymatic systems manifested as a response to physiological redox stimuli rather than a protection against the severe oxidative stress.

New Approaches to Chemical Technologies of Plant Materials for Aromatherapy

A new approach to the production of commercial products used in aromatherapy and household aromatizing agents based on induction heating of plant raw materials and the use of hydrophilic polymer hydrogels is proposed. It is shown that obtaining highly purified essential oils is neither technologically nor economically justified from the point of view of their use in aromatherapy. The proposed approach makes it possible to obtain products for aromatherapy with minimal processing of raw materials and low production costs. The main end product is a polymer hydrogel saturated with a liquid phase formed during induction heating of a mixture of a plant component with metal inclusions. Such a product, among other things, allows the implementation of electronic aromatherapy systems and household aromatizing agents, in which the generation of aroma oils is also provided by induction heating. In the operation of such systems, the basic property of thermosensitive hydrogels is used – a shift in the hydrophobic-hydrophilic balance with temperature variations, which makes it possible to exclude parasitic evaporation of volatile components. Specific technical solutions that implement this approach are proposed.

Exercise to Combat Respiratory Muscle Wasting in Cancer

Cachexia is the term used to describe the progressive loss of muscle mass in association with severe disease. The primary resulting alteration observed in cachexia is a shift in the fundamental balance of muscle protein synthesis and muscle protein degradation. One of the diseases most commonly associated with cachexia is cancer, in which the prevalence rate is 50-80%. Furthermore, cachexia is estimated to be responsible for 20% of cancer deaths. Potentially contributing to this mortality rate is the wasting of the respiratory muscles. Despite this, relatively little research has investigated the impact of cancer cachexia on respiratory muscle wasting and dysfunction. Additionally, exercise provides promise in the implementation of a therapeutic intervention aimed at ameliorating the adverse effects of cancer cachexia.

Involvement of Nitric Oxide in Methyl Jasmonate-Mediated Regulation of Water Metabolism in Wheat Plants under Drought Stress

Drought is a serious challenge that causes significant crop loss worldwide. The developmental processes of plants are regulated by phytohormones and signaling molecules that crosstalk together in signaling cascades. We suppose that nitric oxide (NO) is a secondary messenger of the JAs signaling pathway, as 10−7 M methyl jasmonate (MeJA) pretreatment regulates NO accumulation in wheat plants under drought stress, modulated by 12% polyethylene glycol (PEG), and in control plants. This study aimed to compare 2 × 10−4 M nitric oxide donor sodium nitroprusside (SNP) and MeJA pretreatments in regulating growth and water balance parameters at the vulnerable initial first-leaf stage of wheat growth. The application of 12% PEG decreased transpiration intensity twofold, relative water content (RWC) by 7–9%, and osmotic potential of cell sap by 33–40% compared with those of control plants. Under drought, MeJA- and SNP-pretreated plants decreased transpiration intensity by 20–25%, RWC by 3–4%, and osmotic potential of cell sap by 16–21% compared with those of control plants, and enhanced the proline content by 25–55% compared with MeJA- and SNP-untreated plants. Our results suggest that pretreatment with MeJA as well as SNP could mitigate drought stress in wheat plants. Similarities in MeJA- and SNP-induced shifts in plant water balance suggested that NO is a mediator of MeJA-induced regulation of wheat water content during water deficit.

Contributions to the Characterization of Chromogenic Dyes in Color Slides

Chromogenic reversal films (or color slides) are first-generation positive transparencies. These were used for various purposes, namely as an artistic medium, especially from the 1960s onwards. However, these materials are intrinsically vulnerable to chemical degradation and have poor long-term stability. Although over time significant improvements have been achieved in the stability of chromogenic products, chromogenic dyes are highly susceptible to oxidation and hydrolysis, both induced by light and/or relative humidity and temperature, leading to the fading and shift in the original color balance of the images. During the present investigation, a gap of knowledge regarding chromogenic materials in general, and chromogenic reversal films specifically, was detected. Today, there is still no methodology to identify the dyes present in a specific work and, therefore, to study their chemical mechanism of degradation. From this premise and focused on case studies from the Portuguese artist Ângelo de Sousa (1938–2011), a research study was carried out seeking the characterization of chromogenic dyes. Based on the isolation of the different dyes composing a chromogenic material, several procedures were tested to describe the dyes found in chromogenic reversal films, such as Raman spectroscopy, thin-layer chromatography (TLC), infrared spectroscopy, high-performance liquid chromatography with diode array detector (HPLC-DAD) and coupled with mass spectrometry (HPLC-HRMS). Promising results were achieved with this approach, opening new paths for the understanding of these materials.