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Solvent Exposure and Toxic Responses
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
Alcohols are hydrocarbons substituted with a single hydroxyl group. They are widely used as cleaning agents, thinners, and diluents; as vehicles for paints, pesticides, and pharmaceuticals; as extracting agents; and as chemical intermediates. Methyl alcohol is widely used as an industrial solvent and as an adulterant to denature ethanol to prevent its abuse when used as an industrial solvent. Another important industrial use of methyl alcohol is in the production of formaldehyde. Isopropyl alcohol is used as rubbing alcohol and in the manufacture of acetone. Cyclohexanol is used to produce adipic acid for the production of nylon. In general, the aliphatic alcohols with more than five carbon atoms are divided into the plasticizer range (6 to 11 carbons) and the detergent range (>12 carbons).
Principles of Biology
Published in Arthur T. Johnson, Biology for Engineers, 2019
Epigenetics is the term describing gene expression and its long-term effect on phenotype. It is the study of changes in gene activity that do not involve alterations in the genetic code, but are, nevertheless, passed on to at least one, and maybe more, successive generations (Cloud, 2010). Epigenetic markers include methylation, phosphorylation, or acetylation bound at one or more genetic sites. The effects of these markers are to regulate whether the genes to which they are attached are expressed or not. Methyl groups and other molecules can bind to the helix itself or to its histone protein core and cause the whole assembly to flex. As that happens, some genes are exposed and others are obscured. The exposed genes are the ones that can be actively expressed. When a methyl group is added to a gene, it keeps other regulatory molecules from binding to that gene.
Toxic Pollution
Published in Kimon Hadjibiros, Ecology and Applied Environmental Science, 2013
Organic mercury occurs in the form of methyl mercury CH3Hg+ (soluble, an important pollutant of water bodies) and dimethyl mercury (CH3)2Hg (insoluble). Methyl mercury accumulates in tissues and is particularly toxic. It reaches humans mainly through fish in the diet. It accumulates in the nerve cells, attacks the metabolism of the nervous system and disturbs the action of various enzymes. Its half-life in the human body is around 70 days. The symptoms of poisoning may appear weeks or months after ingestion and include numbness and pain in the lips or hands and feet, ataxia, vision and hearing impairment, and emotional disturbances. This type of illness is known as “Minamata disease” because it appeared for the first time in epidemic form in the small town of Minamata in Japan in the 1950s. There the mercury came from a chemical plant that released its wastes into the sea. It ended up in the bodies of people and animals via the marine food chain. In 1970, 121 serious cases of poisoning including 46 deaths had been officially recognised, but it would appear that the disease affected, to a greater or lesser degree, a much larger number of people. Children born by affected mothers suffered from genetic defects. Other cases of toxic effects have been reported from Iraq, Pakistan and Guatemala, due to consumption of seeds sprayed with a fungicide containing mercury.
Critical and supercritical fatty amide synthesis
Published in Chemical Engineering Communications, 2023
Miguel Gonzalo Arenas-Quevedo, Andrés Adolfo Velasco-Medina, Jesús Gracia-Fadrique
The production of palm oil in the surfactant industry has a great advantage over petroleum-derived products (Piispanen et al. 2003). Different studies show that synthesized methyl esters are used in a variety of industries (Ghandi et al. 2007; Yang et al. 2003; Chinedu et al. 2022), food industries (James et al. 1982; Aravindan et al. 2009) the cosmetics (Boyxen et al. 2001), pharmaceutical (Craig 1995; Perez et al. 2011) and textile industries (Taskovich et al. 1997). Surfactants are substances that degrade slowly, so the industries that synthesize and commercialize them generate a negative impact on the environmental and living organisms (Elraies et al. 2010). For this reason, at present, alternatives for the synthesis and characterization of surfactants from natural products are being sought (Saad et al. 2020).
Animal models and mechanisms of tobacco smoke-induced chronic obstructive pulmonary disease (COPD)
Published in Journal of Toxicology and Environmental Health, Part B, 2023
Priya Upadhyay, Ching-Wen Wu, Alexa Pham, Amir A. Zeki, Christopher M. Royer, Urmila P. Kodavanti, Minoru Takeuchi, Hasan Bayram, Kent E. Pinkerton
In addition to RNA interference, other epigenetic modifications might be mediated by different mechanisms, including DNA methylation and histone modification, which might also play essential roles in COPD development. DNA methylation is a chemical modification that involves addition of a methyl group to cytosine residues in CpG dinucleotides, resulting in formation of 5-methylcytosine. DNA methylation might occur in promoter regions of genes, leading to gene silencing or reduced gene expression. In COPD, alterations in DNA methylation patterns were noted in genes involved in inflammation, oxidative stress, and tissue remodeling, which are critical processes in COPD pathogenesis (Alfahad et al. 2021). Previously Zeng et al. (2020) suggested that cigarette-induced oxidative stress plays a role in mediating pulmonary apoptosis and hypermethylation of the B-cell lymphoma/leukemia-2 (Bcl-2) promoter, an apoptosis regulator, in COPD through DNA methyltransferase enzyme 1 (DNMT1), a key DNA methyltransferase enzyme. Similarly, aberrant DNA methylation was reported to be a widespread occurrence in small airways of COPD patients and was associated with altered expression of genes and pathways related to COPD, such as NF-E2-related factor 2 oxidative response pathway (Vucic et al. 2014).
Association between global DNA methylation (LINE-1) and occupational particulate matter exposure among informal electronic-waste recyclers in Ghana
Published in International Journal of Environmental Health Research, 2022
Ibrahim Issah, John Arko-Mensah, Laura S. Rozek, Katie Rentschler, Thomas P. Agyekum, Duah Dwumoh, Stuart Batterman, Thomas G. Robins, Julius N. Fobil
DNA methylation, the covalent addition of a methyl group to the 5ʹ carbon of cytosine in a CpG dinucleotide, is the most stable and best-studied epigenetic mark that often responds to environmental stimuli and is critical in regulating gene expression and maintaining chromosomal integrity (Jamebozorgi et al. 2018; Lei et al. 2018). Most studies have focused on the influence of PM on either global methylation or gene-specific methylation (Baccarelli et al. 2009; Madrigano et al. 2011; Kile et al. 2013). The Long interspersed nucleotide elements-1 (LINE-1) are often used as surrogates for global DNA methylation measurement, given their relatively uniform spread across the genome (Yang et al. 2004). They are repetitive elements or transposons, constitute approximately 18% of the human genome, and are usually heavily methylated to suppress retrotransposition (Perera et al. 2020). Because DNA methylation marks are labile and respond to environmental stimuli, LINE-1 methylation is often used as an epigenetic biomarker of effect where low methylation levels correlate with genome instability (Rozek et al. 2014).