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Biological response modification of normal tissue reactions: Basic principles and pitfalls
Published in Michael C. Joiner, Albert J. van der Kogel, Basic Clinical Radiobiology, 2018
Selenium stimulates glutathione peroxidase, which is supposed to reduce the level of toxic oxygen compounds in irradiated cells. Only few data are available on potential tumour effects of selenium which, however, do not suggest any detrimental outcome (8). After total-body irradiation of rats, a clear increase in animal survival was found after administration of sodium selenite. Also, protection of salivary glands by sodium selenite has been found in rats (44).
Glutathione Synthesis
Published in Robert A. Greenwald, CRC Handbook of Methods for Oxygen Radical Research, 2018
Glutathione (l-γ-glutamyl-l-cysteinyl-glycine) is found in almost all cells in relatively high concentrations (e.g., 0.5 to 10 mM).1 Glutathione has a number of cellular functions. It is an effective intracellular reductant. It functions in catalysis, metabolism, transport, and in the protection of cells against foreign compounds, free radicals, and reactive oxygen compounds. Of relevance to the subject matter of this volume, glutathione is an active participant in reactions that destroy hydrogen peroxide and organic peroxides, such as those catalyzed by glutathione peroxidase or certain glutathione-S-transferases.
Benzene Metabolism (Toxicokinetics and the Molecular Aspects of Benzene Toxicity)
Published in Muzaffer Aksoy, Benzene Carcinogenicity, 2017
Keith R. Cooper, Robert Snyder
O'Brien77 reported that during the oxidative burst in leukocytes activated by the well-known tumor promoter, phorbol myristate acetate (PMA), phenol, the first metabolite of benzene was oxidized to a reactive metabolite which bound to DNA. The respiratory burst is a phenomenon observed in several types of white cells including neutrophils, eosinophils, monocytes, and macrophages, and is associated with either phagocytosis or a variety of other stimuli.78-82 Ordinarily the respiratory burst occurs only in cells which are termed "activated". The respiratory burst is characterized by the sudden increase in oxygen uptake by the cells and the rapid formation of superoxide radical anion, O2-, hydrogen peroxide, and other reactive oxygen compounds. The cells undergoing the respiratory burst are ordinarily protected from its effects by enzymes such as superoxide dismutase, catalase, and glutathione peroxidase, but these cells may, under some conditions, be damaged or killed by a failure to protect themselves from the products of the respiratory burst. There is also the potential for cells in the immediate vicinity to be damaged by active oxygen and other factors released during the burst.
Protective role of resveratrol and apigenin against toxic effects of bisphenol a in rat salivary gland
Published in Drug and Chemical Toxicology, 2023
Yaser Said Çetin, Fikret Altındağ, Mehmet Berköz
Resveratrol (RSV) and Apigenin (APG) have been shown to have antioxidant, anti-mutagenic, anti-carcinogenic, and anti-inflammatory properties. Due to these properties, it is considered that RSV and FPG can prevent various pathologies such as chronic diseases and cancer. Most of the studies investigating the effects of RSV and APG have focused on cancer, and it has been determined that these compounds have inhibitory and preventive properties in many stages of cancer development (Upadhyay & Dixit 2015; Diaz-Gerevini et al. 2016; Yammine et al. 2020). In this study, we aimed to investigate the cytotoxicity and the cytopathological and apoptotic changes induced by BPA exposure in salivary gland cells and to examine the changes in intracellular reactive oxygen compounds in the presence of oxidative stress, which is considered to have a role in the formation of these effects. We also aimed to evaluate the protective role of RSV and APG against the negative effects of BPA administered at varying doses. The findings to be obtained will be useful in elucidating the effects of BPA exposure on the salivary gland and in the development of preventive approaches to be developed for reducing or eliminating these effects.
Modulatory Effects of Alkaloid Extract from Gongronema latifolium (Utazi) and Lasianthera africana (Editan) on Activities of Enzymes Relevant to Neurodegeneration
Published in Journal of Dietary Supplements, 2019
Esther E. Nwanna, Adeniyi A. Adebayo, Ganiyu Oboh, Opeyemi B. Ogunsuyi, Ayokunle O. Ademosun
Imbalance between free radical generation and the protective mechanism conferred by antioxidants is another implicated factor that triggers and induces AD, as evidenced by the high incidence of lipid oxidation in specific areas of the brain of an AD patient (Lovell et al., 1995). This incidence might be the result of higher polyunsaturated fatty acid (PUFA) content, a higher level of oxidation-induced metals such as iron (Fe) in certain regions, low antioxidant defense, and high oxygen demand by the mammalian brain (Praticò and Delanty, 2000). These characteristics make the brain more susceptible to peroxidation and oxidative modification compared with other organs in the body (Praticò and Delanty, 2000; Uttara et al., 2009). Reactive species (O2−, OH*, and NO) are active oxygen compounds generated by normal aerobic cellular metabolism (Uttara et al., 2009). These radicals are capable of stealing electrons from surrounding molecules and oxidizing the vital components of biological membrane, thereby eliciting oxidative damage to the cell (Lee et al., 2004).
Ultrasound-mediated drug delivery by gas bubbles generated from a chemical reaction
Published in Journal of Drug Targeting, 2018
Sungmun Lee, Leena Al-Kaabi, Aurélie Mawart, Ahsan Khandoker, Habiba Alsafar, Herbert F. Jelinek, Kinda Khalaf, Ji-Ho Park, Yeu-Chun Kim
In this research, bovine serum albumin (BSA) nanoparticles are used as a drug delivery carrier encapsulating luminol that can produce N2 gas bubbles at a disease site only. The microbubbles are generated by a chemical reaction between luminol and H2O2, a reactive oxygen species (ROS). ROS are chemically reactive oxygen compounds including H2O2, hydroxyl radical, and superoxide. ROS are generated naturally as by-products of intracellular metabolism of oxygen [25]. Overproduction of ROS and the ensuing oxidative stress leads to significant damage to normal cell structure, which contributes to the progression of inflammatory disorders and the development of cancers [26]. Tumours and cancer cells further increase ROS levels compared to normal cells both in vitro and in vivo [27,28]. The high levels of H2O2 result from increased metabolic activity, mitochondrial dysfunction, oncogene activity, and increased activity of oxidases [29]. H2O2 is a highly diffusible messenger across the biological membrane and is considered to be a mediator of apoptotic cell death [29,30]. This diffusibility characteristic of H2O2 is utilised by the proposed microbubble delivery system as it generates the required N2 from reacting with luminol.