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Summary and Development of a New Approach to Senescence
Published in Nate F. Cardarelli, The Thymus in Health and Senescence, 2019
The free-radical “theory” of aging supposes that the accumulation of free radicals, and therefore cross-linking in collagen and other tissues, increases with age. The inability to detect the free radicals directly or to alter the course of aging using free-radical scavangers has not much dampened the enthusiasm of its supporters. Antioxidant-enhanced rodent diets are to no avail in regard to life-span, although tumor incidence does decrease.24 Fruitflies and nematodes, however, do seem to respond. (As one might imagine, our knowledge of aging processes in nematodes is sparse indeed.) The question of why free radicals accumulate is usually answered by the reposte that the protective enzyme levels have decreased. There is no reasonable supporting evidence that supraoxide dismutase levels, for instance, are down, and even if true, the reason as to the decrease must still be addressed.
Bronchopulmonary Dysplasia
Published in Lourdes R. Laraya-Cuasay, Walter T. Hughes, Interstitial Lung Diseases in Children, 2019
R. Boynton Bruce, T. Allen Merritt
Oxygen toxicity appears to be mediated through the action of oxidizing radicals released by phagocytes such as neutrophils and pulmonary alveolar macrophages. When phagocytes are exposed to certain stimuli they reduce molecular oxygen (O2) to superoxide anion (O−2) in a NADPH-dependent reaction catalyzed by the plasma membrane-bound enzyme, pyridine nucleotide oxidase.2 Superoxide has been implicated in the initiation of lipid peroxidation, the oxidation of thiol groups, and the oxidation of purines and pyrimidines.3 However, most superoxide reacts rapidly with itself to produce molecular oxygen and hydrogen peroxide in a reaction catalyzed by superoxide dismutase. Superoxide is not only cytotoxic itself, but also can react with hydrogen peroxide to produce hydroxyl radicals (OH·).2 Thus, superoxide dismutase is thought to be a major protective mechanism against oxygen toxicity. The survival time of rats exposed to 100% oxygen increased from 70 to 118 hr when liposomes containing superoxide dismutase and catalase were injected intravenously before and during exposure.4
Herbicides
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Glutathione (GSH) and superoxide dismutase also play a role as cellular defense factors against reactive oxygen species generated in tissues. GSH and superoxide dismutase depletion selectively enhance PQ-induced oxidative stress by further inhibiting the cell’s ability to prevent the damaging effects of free radical generation. In addition, dismutated oxygen (O·, singlet O2) accumulates from O2−, producing an excess of hydroperoxides.* This precipitates a series of potentiating reactions undermining the stability of unsaturated lipids within cell membranes.
D-ribose-L-cysteine exhibits neuroprotective activity through inhibition of oxido-behavioral dysfunctions and modulated activities of neurotransmitters in the cerebellum of Juvenile mice exposed to ethanol
Published in Drug and Chemical Toxicology, 2023
Damilare Adedayo Adekomi, Olamide Janet Olajide, Omowumi Oyeronke Adewale, Akeem Ayodeji Okesina, John Olabode Fatoki, Benedict Abiola Falana, Temidayo Daniel Adeniyi, Adebiyi Aderinola Adegoke, Waliu Adetunji Ojo, Sheriffdeen Oluwabusayo Alabi
Superoxide dismutase is an antioxidant enzyme that catalyzes the conversion of anion superoxide to oxygen and hydrogen peroxide. The reduction of SOD activity in the brain induced by ethanol in this study may be due to the generation of excessive anion, which causes this enzyme to become inactivated. The administration of DRLC provided a better protective effect against ethanol-induced cerebellar damage and this may be due to the high amount of cysteine present in DRLC. Increased SOD and GPx activities observed in this study may correlate to the fact that the high antioxidant activities in DRLC induced endogenous antioxidants thus reduced the free radical activity (Emokpae et al. 2020a). In addition, an increase in the antioxidant activity can be described as an adaptive response to excessive ROS (Haorah et al. 2008). DRLC was sufficient to subdue the ROS generated by the ethanol exposure.
Moringa seed-supplemented diets modulate ACE activity but not its gene expression in L-NAME-induced hypertensive rats
Published in Biomarkers, 2022
Ganiyu Oboh, Odunayo O. Oluokun, Sunday I. Oyeleye, Opeyemi B. Ogunsuyi
The effect of moringa seed-supplemented diets on antioxidant enzymes; catalase (CAT), glutathione-S-transferase (GST), and superoxide dismutase (SOD) in experimental rats are shown in Figures 6–8. There was no significant (p > 0.05) difference in the activities of catalase (CAT), glutathione-S- transferase (GST), and superoxide dismutase (SOD) of the normotensive control group and normotensive groups fed a diet supplemented with moringa seeds. A significant reduction in CAT, SOD, and GST activities in induced rats was recorded, however, a significantly increased activity of CAT and SOD of hypertensive groups treated with the sample and positive control group was recorded when compared to the induced group. The 5% dietary inclusion of moringa seed resulted in a significantly increased CAT and reduced GST activity when compared with the positive control group.
Impact of nonionizing electromagnetic radiation on male infertility: an assessment of the mechanism and consequences
Published in International Journal of Radiation Biology, 2022
Rohit Gautam, Eepsita Priyadarshini, JayPrakash Nirala, Paulraj Rajamani
Besides these, studies also demonstrate the harmful effect of radiations on humans leading to reduction in sperm motility, viability along with increased ROS generation (Agarwal et al. 2009). In one such study, men exposed to combination of EMR (1800 MHz) and wi-fi (2.45 GHz) were divided into 3 groups. While the 1st group was exposed for 30 min duration, 2nd and 3rd groups were exposed to 31-120 min and >120 mins respectively. The results showed that increase in exposure time results in enhancement of ROS and increased expression of 8-OHdG leading to DNA fragmentation. Besides this, decrease in total antioxidant capacity, glutathione and superoxide dismutase were also observed. Sperm count, vitality, and motility was also found to decrease significantly (Ding, Ping, et al. 2018). In another study, sperm samples were collected from 32 healthy individuals and exposed to 900/1800 MHz for 5 hours. Analysis of sperm parameters signified progressive decrease in sperm motility and increase in DNA fragmentation formation on exposure (Gorpinchenko et al. 2014a). Table 1 summarizes some of studies performed for determination of the effect of EMR on in vivo and in vitro system.