Lab-on-a-Chip-Based Devices for Rapid and Accurate Measurement of Nanomaterial Toxicity
Suresh C. Pillai, Yvonne Lang in Toxicity of Nanomaterials, 2019
Engineered nanomaterials with distinctive size, shape, surface structure, aggregation, and solubility parameters can be dedicated to a wide variety of important industrial processes. While these materials bring many advantages in current technology and research, the lack of a full understanding of their risks is a prevalent danger. Despite this there is evidence to support the fact that the benefits may outweigh the risks for possible applications in therapeutics. For example, Doxorubicin, a chemotherapeutic drug which exerts a high level of toxicity, can be delivered to the target cell types precisely using integrated nanomaterials without harming the neighbouring healthy cells (Prados et al. 2012). The cytotoxicity induced by nanomaterial exposure is believed to originate from the interaction of an electron donor or acceptor with an oxygen group on the NM, which can create a superoxide radical. Once formed, superoxide radicals are able to create more reactive oxygen species (ROS). ROS induces protein degradation, denaturation, DNA damage, mutagenesis, carcinogenesis, and altered cell cycle regulation (Manke et al. 2013). In addition, they can be uptaken by neuronal tissue, leading to brain and/or nervous system injury (Buzea et al. 2007) Once inside the mitochondria, NM can also cause energy failure (Nel 2007). For these diverse reasons, it is evident a thorough understanding of nanotoxicity must be developed in parallel with biomedical sensors that can measure it.
Photosensitive Manifestations of HIV Disease
Clay J. Cockerell, Antoanella Calame in Cutaneous Manifestations of HIV Disease, 2012
Normal cellular respiration produces a baseline level of reactive oxygen species (ROS), including superoxides, hydrogen peroxide, hydroxyl radicals, and nitric oxide. The immune system adds to these free radicals in the form of reactive oxygen bursts as a response whenever something stimulates polymorphonuclear cells, monocytes/macrophages, or T cells. In an HIV-infected patient, the HIV infection itself and the numerous opportunistic infections secondary to it generate a state of chronic immune activation that is exacerbated by often misdirected reactions to other antigenic substances. This worsens as CD4+ helper T cells that normally regulate and direct immune activity fall to pathologically low levels and immune regulation breaks down, creating a state of constant oxidative stress.6
Iron, Oxygen Stress, and The Preterm Infant
Bo Lönnerdal in Iron Metabolism in Infants, 2020
A one-electron reduction of oxygen gives rise to the superoxide radical (·O2−) (Table 1). ·O2− is formed in almost all aerobic cells.6 The generation of ·O2− is associated with several deleterious effects on the organism including DNA degeneration,4 loss of viscosity of human synovial fluid,7 and damage to cell membranes.8 The generation of ·O2− is also a vital part in the bacterial killing by phagocytic cells. ·O2− is released in neutrophils, eosinophils, monocytes, and macrophages in a series of metabolic events usually referred to as “respiratory burst”. ·O2−, however, is by itself quite unreactive.10 The toxic effects seen after the generation of ·O2− are considered to be caused by the formation of more reactive oxidizing radicals, especially the hydroxyl radical.11
Can intravenous oxytocin infusion counteract hyperinflammation in COVID-19 infected patients?
Published in The World Journal of Biological Psychiatry, 2021
Benjamin Buemann, Donatella Marazziti, Kerstin Uvnäs-Moberg
The anti-inflammatory effect of oxytocin may also involve a suppression of the gene expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. This enzyme is responsible for the inflammation induced superoxide production and thereby the formation of Reactive Oxygen Species (ROS). Such an effect of oxytocin was demonstrated in kidney homogenate from rats being treated with intraperitoneal injection of cisplatin (Rashed et al. 2011). In the same study, the gene expression of p38 mitogen-activated protein kinase (MAPK), an enzyme involved in the apoptotic pathway, was also reduced by oxytocin. The latter effect may protect the tissue against further destruction. These observations are in line with findings of a decreased basal and stimulated NADPH-dependent superoxide activity in human vascular cells, monocytes, and macrophages when the cells were incubated with oxytocin at physiological levels (Szeto et al. 2008).
Protective effect of Euphorbia thymifolia and Euphorbia hirta against carbon tetrachloride-induced hepatotoxicity in Wistar rats
Published in Drug Development and Industrial Pharmacy, 2022
Balamuralikrishnan Balasubramanian, Wen-Chao Liu, Vijaya Anand Arumugam, Durai Muthu Mani Gurupalraj, Manikandan Ramasamy, Shenbagam Madhavan, Shanmugam Velayuthaprabhu, Sungkwon Park
Superoxide radicals are neutralized by SOD, which converts them into H2O2. The percentage of inhibition of superoxide anion formation is directly proportional to the anti-oxidant potency of plant extracts. In the present study, the ethanolic extract of both the leaves of E. thymifolia and E. hirta has a potent inhibition power of superoxide anion formation. Previous studies also showed a similar effect of Psidium guajava leaves extract on superoxide anion radical scavenging activity [36]. Among ROS which is deleterious and leads to oxidative damages, H2O2 is less reactive than superoxide anion or hydroxyl radical, but it can be toxic when it is converted into hydroxyl radical in cells [37]. Decreasing H2O2 level is an important anti-oxidant power which is the ability to protect cells from oxidative damage [38]. Scavenging of H2O2 by extracts of E. thymifolia and E. hirta may be attributed to their phenolics and other active components which can donate electrons to H2O2 and then neutralizing it to water. The aerial parts of Sorghum halepense have the potential source of bioactive compounds, which may help to treat free radical associated disorders [39].
Protective effect and mechanism of low P50 haemoglobin oxygen carrier on isolated rat heart
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2022
Wentao Zhou, Shen Li, Shasha Hao, Honghui Zhang, Tao Li, Wanjing Li, Jiaxin Liu, Hong Wang, Chengmin Yang
The inflammation score of photomicrographs of HE-stained of cardiac tissue in the low P50 HBOCs was significantly lower the control group (p < .05). The results suggest that a reasonable oxygen supply can effectively improve MI. It is most commonly thought that main cause of toxicity is not oxygen but ROS that are formed as a product of oxygen metabolism. Protons are transported across the inner mitochondrial membrane by an electron transport chain that finishes in the acceptance of electrons by molecular oxygen. Meanwhile, a small amount of these electrons are incompletely reduced to form the superoxide radical, oxygen. Superoxide can react with lipids to form lipid peroxides, and excessive superoxide can cause apoptosis and premature cell death. Thus one important implication that oxygen supply be carefully linked to energy production is that ATP production, in excess of demand, could lead to excessive accumulation of ROS. The possible reason is that the effects of ischaemic injury in the control group are similar the cause of MI of ROS generated in the body by overload of oxygen supply in high and medium P50 HBOCs, so the myocardium of rats in the high and medium P50 HBOCs group are similar to the control group, the results appear to exclude ROS as culprit of injury, and oxidative stress as a mechanism of protection for low P50 HBOCs.
Related Knowledge Centers
- Chemical Compound
- Chemistry
- Molecular Orbital
- Oxygen
- Reactive Oxygen Species
- Ion
- Redox
- Allotropes of Oxygen
- Diradical
- Radical