CHARACTERISTIC OF FREE-RADICAL DAMAGE AND ANTIOXIDANT PROTECTION STATE IN PATIENTS WITH CHRONIC KIDNEY DISEASE AGAINST A BACKGROUND OF MALABSORPTION SYNDROME

Oxidation processes play an important role in damage of the renal structures, especiallyagainst a background of other serious pathologies, in particular, malabsorptionsyndrome.The study of the mechanisms of mutual aggravation and progression of kidneydamage against a background of malabsorption is a very urgent problem of the presenttime.Purpose - to investigate the state of free radical oxidation of lipids, proteins andantioxidant defense in patients with chronic kidney disease of different ages withoxaluria against a background of malabsorption syndrome.Material and methods. 98 patients with chronic kidney disease of the I-II stages(pyelonephritis) with the presence of oxaluria against a background of malabsorptionsyndrome of different age were examined.The age of the patients under examination was32 - 64. All patients underwent a study of the system of free radical oxidation of lipidsand proteins.Results. chronic kidney disease with the presence of oxaluria is accompanied by asignificant increase in the blood content of free radical oxidation products, namelyaldehyde and ketone dinitrophenylhydrazones, especially of a neutral nature,malondialdehyde, as well as a significant decrease in the indicators of the antioxidantdefense system, which manifested itself to a greater extent in patients with older age.groups.Conclusion. An essential factor in the development and progression of chronic kidneydisease with the presence of oxaluria against a background of malabsorption syndromeis an increase in the intensity of free radical oxidation of lipids and proteins (mainly dueto aldehyde and ketondinitrophenylhydrazones of a neutral nature).

Some indicators of free radical oxidation and antioxidant protection in the erythrocytes of former athletes

Objective: to study the main indicators of free radical oxidation and antioxidant protection in the erythrocytes of former athletes, depending on the period of termination of sports.Materials and methods: 24 former male athletes aged 19–29 years were examined, who were divided into 2 groups of 12 people each (1st group — former athletes who stopped training for up to 2 years; 2nd — over 2 years). The control group consisted of 15 practically healthy untrained student volunteers of the same age. In erythrocytes, spectrophotometrically (spectrophotometer Shimadzu 1240, Japan), the activity of antioxidant enzymes was determined: superoxide dismutase (SOD) (K.F. 1.15.1.1) — by inhibiting the reduction of nitro blue tetrazolium by superoxide anion radical at λ = 540 nm, after preliminary processing of erythrocytes by the method of Dubinina E.E. and others [8]; catalase (K.F. 1.11.1.6) — according to the rate of utilization of hydrogen peroxide at λ = 260 nm; glutathione peroxidase (HP) (KF 1.11.1.9) — by the change in the content of reduced glutathione in samples before and after incubation of the substrate with dithiobis-nitrobenzoic acid at λ = 412 nm; glutathione reductase (GR) (K.F. 1.6.4.2) — according to the catalytic NADPH ∙ H+-dependent transformation of the oxidized form of glutathione into the reduced form, the intensity of which was estimated by the rate of decrease in the extinction of samples at λ = 340 nm, at which the NADPH H+ solution has a maximum light absorption (Warburg test).Results: the direction of the shifts in the state of the oxidative balance was established depending on the period of detraining. A significantly lower value of the total antioxidant activity was revealed in the former athletes of the 1st group. This phenomenon is probably associated with a decrease in the efficiency of the enzymatic link of the antioxidant defense in the absence of regular physical exertion, and, as a consequence, an increased consumption of non-enzymatic antioxidants. It was found that the early post-sports period is characterized by significantly lower, in comparison with the control group, the values of the activity of the first-order enzymes (superoxide dismutase) against the background of the increased activity of the second-order enzymes (catalase).Conclusions: the obtained data can be recommended for monitoring the state of athletes who stopped playing sports and taken into account when prescribing rehabilitation measures for the corresponding contingent.

Dihydroxyacetone valorization with high atom efficiency via controlling radical oxidation pathways over natural mineral-inspired catalyst

Diminishing fossil fuel resources and calls for sustainability are driving the urgent need for efficient valorization of renewable resources with high atom efficiency. Inspired from the natural goethite mineral with Mn paragenesis, we develop cost-effective MnO2/goethite catalysts for the efficient valorization of dihydroxyacetone, an important biomass-based platform molecule, into value-added glycolic acid and formic acid with 83.2% and 93.4% yields. The DHA substrates first undergo C−C cleavage to selectively form glycolic acid and hydroxymethyl (·CH2OH) radicals, which are further oxidized into formic acid. The kinetic and isotopic labeling experiments reveal that the catalase-like activity of MnO2 turns the oxidative radicals into oxygen, which then switches towards a hydroxymethyl peroxide (HMOO) pathway for formic acid generation and prevents formic acid over-oxidation. This nature-inspired catalyst design not only significantly improves the carbon efficiency to 86.6%, but also enhances the oxygen atom utilization efficiency from 11.2% to 46.6%, indicating a promising biomass valorization process.

Nighttime and daytime dark oxidation chemistry in wildfire plumes: an observation and model analysis of FIREX-AQ aircraft data

Wildfires are increasing in size across the western US, leading to increases in human smoke exposure and associated negative health impacts. The impact of biomass burning (BB) smoke, including wildfires, on regional air quality depends on emissions, transport, and chemistry, including oxidation of emitted BB volatile organic compounds (BBVOCs) by the hydroxyl radical (OH), nitrate radical (NO3), and ozone (O3). During the daytime, when light penetrates the plumes, BBVOCs are oxidized mainly by O3 and OH. In contrast, at night or in optically dense plumes, BBVOCs are oxidized mainly by O3 and NO3. This work focuses on the transition between daytime and nighttime oxidation, which has significant implications for the formation of secondary pollutants and loss of nitrogen oxides (NOx=NO+NO2) and has been understudied. We present wildfire plume observations made during FIREX-AQ (Fire Influence on Regional to Global Environments and Air Quality), a field campaign involving multiple aircraft, ground, satellite, and mobile platforms that took place in the United States in the summer of 2019 to study both wildfire and agricultural burning emissions and atmospheric chemistry. We use observations from two research aircraft, the NASA DC-8 and the NOAA Twin Otter, with a detailed chemical box model, including updated phenolic mechanisms, to analyze smoke sampled during midday, sunset, and nighttime. Aircraft observations suggest a range of NO3 production rates (0.1–1.5 ppbv h−1) in plumes transported during both midday and after dark. Modeled initial instantaneous reactivity toward BBVOCs for NO3, OH, and O3 is 80.1 %, 87.7 %, and 99.6 %, respectively. Initial NO3 reactivity is 10–104 times greater than typical values in forested or urban environments, and reactions with BBVOCs account for >97 % of NO3 loss in sunlit plumes (jNO2 up to 4×10-3s-1), while conventional photochemical NO3 loss through reaction with NO and photolysis are minor pathways. Alkenes and furans are mostly oxidized by OH and O3 (11 %–43 %, 54 %–88 % for alkenes; 18 %–55 %, 39 %–76 %, for furans, respectively), but phenolic oxidation is split between NO3, O3, and OH (26 %–52 %, 22 %–43 %, 16 %–33 %, respectively). Nitrate radical oxidation accounts for 26 %–52 % of phenolic chemical loss in sunset plumes and in an optically thick plume. Nitrocatechol yields varied between 33 % and 45 %, and NO3 chemistry in BB plumes emitted late in the day is responsible for 72 %–92 % (84 % in an optically thick midday plume) of nitrocatechol formation and controls nitrophenolic formation overall. As a result, overnight nitrophenolic formation pathways account for 56 %±2 % of NOx loss by sunrise the following day. In all but one overnight plume we modeled, there was remaining NOx (13 %–57 %) and BBVOCs (8 %–72 %) at sunrise.

Pathophysiological bases of maladjustment formation in high mountains and polar zones

The pathophysiological features of the development of maladjustment under mountain-cold conditions as a manifestation of the syndrome of mutual burdening are considered. In this study, contents of various literary sources, characterizing a persons resistance to the effects of a complex of factors under high mountains and polar zones conditions, were analyzed. With the simultaneous exposure to hypoxia and hypothermia from a pathophysiological point of view, intersecting links of terminological paths, often having diametrically opposite dynamics of changes in the characterized concepts, will be significant. Thus, in the terminological mitochondrial pathway of energy metabolism, uncoupling proteins are present, which, to increase the resistance to hypothermia, should be activated to switch the energy metabolism to predominantly use fatty acids. However, hypoxic conditions should be suppressed to maintain the level of adenosine triphosphate acid available for cells. In the terminological tract of compensatory reactions in response to hypoxemia, the volume of pulmonary ventilation is released, which must increase to improve tolerance to hypoxia, which, under mountain-cold conditions, increased heat loss and promote the deterioration of the condition, i.e., tolerance to low temperatures. Under hypoxic and hypothermic conditions, a synergistic interaction can form, which can be manifested by the development of a syndrome of mutual burdening, which will result in a significant decrease in the functional capabilities of the body, result, and productivity. Maladjustment to mountain cold, with maximum probability, will manifest as disorders of the central nervous system, decreased physical performance, depletion of the functional and regulatory reserves of the body, functional immunodeficiency, decreased regenerative potential, and development of endogenous intoxication. With a high degree of probability, a significant synergistic interaction of hypoxia and hypothermia can be found in relation to the indicators of pulmonary ventilation, blood gases (hypercapnia), acidbase balance (gas alkalosis and lactic acidosis), heart rate (tachycardia), blood pressure (hypotension), central venous pressure (increase), blood viscosity (increase) and its coagulability (hypercoagulation), peroxide and free radical oxidation (activation), and protein catabolism (increase). These changes will negatively affect the functional state of specialists performing complex professional tasks in polar latitudes.

Effects of His-Phe-Arg-Trp-Pro-Gly-Pro peptide on free-radical oxidation processes in conditions of chronic restraint stress

Studying the effects of regulatory peptides on the stress-induced shifts in the bodily processes is of great fundamental and applied significance. Currently, a wide range of peptide neurotropic drugs, affecting the stress response development, are used in medicine, and new promising molecules are being studied. The study was aimed to assess the effects of the adrenocorticotropic hormone (ACTH) synthetic analog, ACTH(6-9)-Pro-Gly-Pro, administered at a dose of 5, 50 and 500 μg/kg, on the free-radical oxidation processes in Wistar rats, subjected to chronic restraint stress (CRS) during two weeks. Serum levels of 8-oxo-2'-deoxyguanosine (8-OHdG) and superoxide dismutase 3 (SOD3) were assessed by enzyme immunoassay, and the levels of thiobarbituric acid reactive substances (TBARS) were assessed by fluorimetric method. CRS lead to the significant increase in the 8-OHdG levels by 18.4% (p = 0.01) and the decrease in the SOD3 levels by 14.3% (p = 0.01), however, it had no effect on the levels of TBARS. ACTH(6-9)-Pro-Gly-Pro, administered at a dose of 5 and 50 μg/kg, significantly decreased the levels of 8-OHdG by 19.8% (p = 0.03) and 30% (p = 0.001), respectively. Thus, it was found that CRS resulted in oxidative stress in animals. ACTH(6-9)-Pro-Gly-Pro administration at a dose of 5 and 50 μg/kg inhibits the stress-induced free-radical oxidation processes.