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1.
The Free Radical Diseases of Prematurity: From Cellular Mechanisms to Bedside.
Perrone, S, Santacroce, A, Longini, M, Proietti, F, Bazzini, F, Buonocore, G
Oxidative medicine and cellular longevity. 2018;:7483062
Abstract
During the perinatal period, free radicals (FRs) are involved in several physiological roles such as the cellular responses to noxia, the defense against infectious agents, the regulation of cellular signaling function, and the induction of a mitogenic response. However, the overproduction of FRs and the insufficiency of an antioxidant mechanism result in oxidative stress (OS) which represents a deleterious process and an important mediator of damage to the placenta and the developing fetus. After birth, OS can be magnified by other predisposing conditions such as hypoxia, hyperoxia, ischemia, hypoxia ischemia-reperfusion, inflammation, and high levels of nonprotein-bound iron. Newborns are particularly susceptible to OS and oxidative damage due to the increased generation of FRs and the lack of adequate antioxidant protection. This impairment of the oxidative balance has been thought to be the common factor of the so-called "free radical related diseases of prematurity," including retinopathy of prematurity, bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, kidney damage, and oxidative hemolysis. In this review, we provide an update focused on the factors influencing these diseases refining the knowledge about the role of OS in their pathogenesis and the current evidences of such relationship. Mechanisms governing FR formation and subsequent OS may represent targets for counteracting tissue damage.
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2.
Sources of free radicals and oxidative stress in the oral cavity.
Żukowski, P, Maciejczyk, M, Waszkiel, D
Archives of oral biology. 2018;:8-17
Abstract
OBJECTIVE An oral cavity is a place especially susceptible to oxidative damage. It is subjected to many environmental pro-oxidative factors or factors that have the ability to generate reactive oxygen species (ROS). The aim of this article is to present the main sources of ROS and oxidative stress in the oral environment. DESIGN A literature search was performed using the PubMed and Google Scholar databases. RESULTS One of the most important ROS sources in the oral cavity is periodontal inflammation. Other sources of ROS include: xenobiotics (ethanol, cigarette smoke, drugs), food (high-fat diet, high-protein diet, acrolein), dental treatment (ozone, ultrasound, non-thermal plasma, laser light, ultraviolet light), and dental materials (fluorides, dental composites, fixed orthodontic appliances, and titanium fixations). It has been shown that excessive production of ROS in the oral cavity may cause oxidative stress and oxidative damage to cellular DNA, lipids, and proteins, thus predisposing to many oral and systemic diseases. CONCLUSIONS Recognition of the exogenous sources of ROS and limitation of exposure to the ROS generating factors can be one of the prophylactic measures preventing oral and systemic diseases. It is suggested that antioxidant supplementation may be helpful in people exposed to excessive production of ROS in the oral cavity system.
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3.
Selenoproteins are involved in antioxidant defense systems in thalassemia.
Genc, GE, Ozturk, Z, Gumuslu, S
Metallomics : integrated biometal science. 2017;(9):1241-1250
Abstract
Thalassemia major (TM) is a hereditary blood disease that affects the production of hemoglobin, resulting in severe anemia. Iron overload because of repeated blood transfusion and increased intestinal iron absorption and hemolysis are the major causes of increased oxidative stress in these patients. Growth and maturational delay, cardiomyopathy, endocrinopathies, and osteoporosis are the complications of thalassemia, secondary to anemia and iron overload. The human body has endogenous defense mechanisms to help protect against free radical-induced cell damage. Selenoproteins are important enzymes involved in these antioxidant defense mechanisms. In thalassemia patients, selenoproteins are essential because of their potential defense against oxidative damage due to iron overload and hemolysis. The aim of this review is to provide an overview of data regarding selenoproteins including glutathione peroxidase, thioredoxin reductase and iodothyronine deiodinases in TM patients. We also underline some complications of thalassemia that may be associated with selenoproteins.
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4.
Evaluation of plasma oxidative stress, with or without antioxidant supplementation, in superficial partial thickness burn patients: a pilot study.
Raposio, E, Grieco, MP, Caleffi, E
Journal of plastic surgery and hand surgery. 2017;(6):393-398
Abstract
BACKGROUND Oxidative stress is one of the main causes of pathophysiological alterations observed during burn injury. The present pilot study aimed to determine whether a specific oral antioxidant supplementation could in any way influence free radical blood values in patients affected by superficial partial thickness burns. MATERIALS AND METHODS Plasma oxidants and plasma antioxidant capacity were analysed in 20 superficial partial thickness burn patients for a 2-week period; patients were randomly divided into two groups, one of which was supported with a specifically designed oral antioxidant formula (Squalene 100 mg, Vitamin C 30 mg, Coenzyme Q10 10 mg, Zinc 5 mg, Beta Carotene 3.6 mg, Bioflavonoids 30 mg, Selenium 55 mcg) administered daily, starting from the day of admission, for the whole study period. RESULTS No significant differences were found in plasma oxidants and plasma antioxidant capacity between the two groups of patients. CONCLUSIONS These results did not reflect any significant benefits of an antioxidant oral supplementation at usual dosages when considering oxidative plasmatic values of superficial partial thickness burn patients.
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Hepatic Effects of Estrogen on Plasma Distribution of Small Dense Low-Density Lipoprotein and Free Radical Production in Postmenopausal Women.
Nii, S, Shinohara, K, Matsushita, H, Noguchi, Y, Watanabe, K, Wakatsuki, A
Journal of atherosclerosis and thrombosis. 2016;(7):810-8
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Abstract
AIM: Hepatic effects of estrogen therapy on low-density lipoprotein (LDL) subfraction or oxidative stress have not been previously evaluated. The purpose of the present study was to investigate whether the differential hepatic effects of estrogen affect plasma distribution of small dense LDL and free radical production in postmenopausal women. METHODS In all, 45 postmenopausal women were given 0.625 mg/day of oral conjugated equine estrogen (CEE) (n=15), 1.0 mg/day of oral 17β estradiol (E2) (n=15), or 50 μg/day of transdermal 17βE2 (n=15) for 3 months. Subjects received either estrogen alone or with dydrogesterone at 5 mg/day. Plasma concentrations of sex hormone-binding globulin (SHBG), lipids, metallic ions, and derivatives of reactive oxygen metabolites (d-ROMs) were measured. RESULTS CEE, but not oral 17βE2, increased the plasma concentrations of triglyceride, copper (Cu), and d-ROMs and the ratio of small dense LDL/total LDL cholesterol, a marker for plasma distribution of small dense LDL. Transdermal 17βE2 decreased d-ROMs concentrations but did not significantly change other parameters. Plasma concentrations of SHBG increased in the 3 groups. Estrogen-induced changes in triglyceride correlated positively either with changes in SHBG (R=0.52, P=0.0002) or the ratio of small dense LDL/total LDL cholesterol (R=0.65, P<0.0001). Changes in Cu also correlated positively either with changes in SHBG (R=0.85, P<0.0001) or d-ROMs (R=0.86, P<0.0001). CONCLUSION The hepatic effects of different routes or types of estrogen therapy may be associated with plasma distribution of small dense LDL and free radical production in postmenopausal women.
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[Molecular effects of mitochondrial mutations in cytochrome b of complex III and their impact on the levels of free radical production].
Borek, A, Ekiert, R, Osyczka, A
Postepy biochemii. 2016;(2):162-172
Abstract
Cytochrome bc1 (mitochondrial complex III) is a common element of several bioenergetic systems. This enzyme catalyses electron transfer from ubiquinol to cytochrome c coupled to translocation of protons across the membrane, which contributes to generation of protonmotive force utilized for ATP production. Cytochrome b, together with cytochrome c1 and iron-sulfur protein (ISP), forms the evolutionarily conserved catalytic core. Transfer of electrons within this enzyme, is facilitated by the movement of ISP domain that allows communication between cytochrome b and cytochrome c1. Mutations in the subunits of catalytic core may cause mitochondrial diseases, however elucidation of their molecular effects in human cells is difficult. For that reason yeast or bacterial systems are used. It was found that some mutations in cytochrome b influence the movement of ISP and, in consequence, the levels of superoxide generation. By exploring the effects of mitochondrial mutations in model systems one can not only learn about molecular basis of diseases but also gain insights about catalytic and side reactions in cytochrome bc1.
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Effect of vitamin A administration on free radicals and lactate levels in individuals exercised to exhaustion.
Patlar, S, Baltaci, AK, Mogulkoc, R
Pakistan journal of pharmaceutical sciences. 2016;(5):1531-1534
Abstract
This study was performed to explore the effect of vitamin A administration on Free Radicals production and antioxidant system activity and lactate levels in individuals exercised to exhaustion The study registered 10 healthy sedentary males their mean age was 22,85±0,26 years. The subjects were orally administrated with 300 mg vitamin A (retinol) for 4 weeks and engaged in strenuous exercise (using the Bruce protocol) once a week. Blood samples were collected from the subjects at four different times, before and after the supplementation and before and after exercise to analyze Malondialdehyde (MDA), Nitric oxide (NO), Glutathione (GSH), Glutathione peroxidase (GSH-Px), Catalase (CAT), Superoxide dismutase (SOD) levels using colorimetric ELISA test kits and plasma lactate levels using an autoanalyzer. Exhaustion exercise leaded to an increase in both MDA, NO, and lactate, and GSH, GSH-Px, CAT and SOD levels compared to resting levels both before and after supplementation (p<0.05). Increased NO levels found in pre-supplementation exhaustion showed a significant decrease after the supplementation of vitamin A (p<0.05), but the other parameters were not changed after vitamin A administration. The results of our study demonstrate that the increase caused by 4-week strenuous exercise in the levels of the free radical NO was offset by vitamin A supplementation. It can be suggested that supplementation of vitamin A at physiological doses has a limited effect on lipid peroxidation caused by strenuous exercise.
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Non-photochemical Fluorescence Quenching in Photosystem II Antenna Complexes by the Reaction Center Cation Radical.
Paschenko, VZ, Gorokhov, VV, Grishanova, NP, Korvatovskii, BN, Ivanov, MV, Maksimov, EG, Mamedov, MD
Biochemistry. Biokhimiia. 2016;(6):583-90
Abstract
In direct experiments, rate constants of photochemical (kP) and non-photochemical (kP(+)) fluorescence quenching were determined in membrane fragments of photosystem II (PSII), in oxygen-evolving PSII core particles, as well as in core particles deprived of the oxygen-evolving complex. For this purpose, a new approach to the pulse fluorometry method was implemented. In the "dark" reaction center (RC) state, antenna fluorescence decay kinetics were measured under low-intensity excitation (532 nm, pulse repetition rate 1 Hz), and the emission was registered by a streak camera. To create a "closed" [P680(+)QA(-)] RC state, a high-intensity pre-excitation pulse (pump pulse, 532 nm) of the sample was used. The time advance of the pump pulse against the measuring pulse was 8 ns. In this experimental configuration, under the pump pulse, the [P680(+)QA(-)] state was formed in RC, whereupon antenna fluorescence kinetics was measured using a weak testing picosecond pulsed excitation light applied to the sample 8 ns after the pump pulse. The data were fitted by a two-exponential approximation. Efficiency of antenna fluorescence quenching by the photoactive RC pigment in its oxidized (P680(+)) state was found to be ~1.5 times higher than that of the neutral (P680) RC state. To verify the data obtained with a streak camera, control measurements of PSII complex fluorescence decay kinetics by the single-photon counting technique were carried out. The results support the conclusions drawn from the measurements registered with the streak camera. In this case, the fitting of fluorescence kinetics was performed in three-exponential approximation, using the value of τ1 obtained by analyzing data registered by the streak camera. An additional third component obtained by modeling the data of single photon counting describes the P680(+)Pheo(-) charge recombination. Thus, for the first time the ratio of kP(+)/kP = 1.5 was determined in a direct experiment. The mechanisms of higher efficiency for non-photochemical antenna fluorescence quenching by RC cation radical in comparison to that of photochemical quenching are discussed.
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9.
Regulation of exercise blood flow: Role of free radicals.
Trinity, JD, Broxterman, RM, Richardson, RS
Free radical biology & medicine. 2016;:90-102
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Abstract
During exercise, oxygen and nutrient rich blood must be delivered to the active skeletal muscle, heart, skin, and brain through the complex and highly regulated integration of central and peripheral hemodynamic factors. Indeed, even minor alterations in blood flow to these organs have profound consequences on exercise capacity by modifying the development of fatigue. Therefore, the fine-tuning of blood flow is critical for optimal physical performance. At the level of the peripheral circulation, blood flow is regulated by a balance between the mechanisms responsible for vasodilation and vasoconstriction. Once thought of as toxic by-products of in vivo chemistry, free radicals are now recognized as important signaling molecules that exert potent vasoactive responses that are dependent upon the underlying balance between oxidation-reduction reactions or redox balance. Under normal healthy conditions with low levels of oxidative stress, free radicals promote vasodilation, which is attenuated with exogenous antioxidant administration. Conversely, with advancing age and disease where background oxidative stress is elevated, an exercise-induced increase in free radicals can further shift the redox balance to a pro-oxidant state, impairing vasodilation and attenuating blood flow. Under these conditions, exogenous antioxidants improve vasodilatory capacity and augment blood flow by restoring an "optimal" redox balance. Interestingly, while the active skeletal muscle, heart, skin, and brain all have unique functions during exercise, the mechanisms by which free radicals contribute to the regulation of blood flow is remarkably preserved across each of these varied target organs.
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The COFU3 Study. Improvement in cognitive function, attention, mental performance with Pycnogenol® in healthy subjects (55-70) with high oxidative stress.
Belcaro, G, Dugall, M, Ippolito, E, Hu, S, Saggino, A, Feragalli, B
Journal of neurosurgical sciences. 2015;(4):437-46
Abstract
AIM: This 12-month product registry study evaluated the effects of supplementation with French pine bark extract (Pycnogenol(®)) on cognitive function, attention, and mental performance in healthy subjects with high oxidative stress. METHODS Healthy subjects (age range 55-70) were screened - within a cardiovascular screening program - for oxidative stress. Out of 150 subjects, high oxidative stress was present in 44; the use of the supplement Pycnogenol(®) was suggested (100 mg/day). These subjects decided to use Pycnogenol(®) and accepted to be evaluated by assessing cognitive functions. A group of subjects with comparable oxidative stress was followed as a reference. IQ Code (Informant Questionnaire on Cognitive Decline in the Elderly), daily tasks, cognitive function, oxidative stress and the short Blessed tests (SBT) were used (in defined scales) to evaluate cognitive functions (COFU). RESULTS As for the IQ Code, at 12 months there was a significantlty total lower score in Pycnogenol(®) patients and also a lower value (P<0.05) for 14 out of 16 items in the questionnaire. Daily tasks: all items were improved (P<0.05) with supplementation in comparison with controls. The improvement was seen for all 12 items (P<0.05) with the supplement. Cognitive function values (visual scale line) indicated a significant improvement (P<0.05) in all elements present in the questionnaire with the 12-month supplementation (no significant variations in controls). Oxidative stress was comparable in both groups at inclusion. It was significantly decreased with Pycnogenol(®) (-28.07%; P<0.05) at 12 months; there was no decrease in controls. The short blessed test (SBT) value was significantly increased in controls (P<0.05); but significantly decreased in the Pycnogenol(®) group (P<0.05). Values for supplemented patients at 12 months were almost within the normal range (21 out or 38 were below the normal value of 4). Tolerability and compliance for Pycnogenol(®) were optimal with >97% of the doses of the supplement correctly used. No side effects were observed, recorded or described. CONCLUSION Pycnogenol(®) supplementation for 12 months appears to improve cognitive function and oxidative stress in normal subjects between 55 and 70 years of age.