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Organic Chemicals
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
In 1980, the annual production of xylene in the United States was 11.1 × 109 pounds.244 This production has steadily increased over the last 32 years. Xylenes are used for industrial cleaning, degreasing, processing, extracting, and thinning solvents.245 Mixed xylenes are used a diluents in the paint industry, in agricultural sprays for insecticides and in gasoline blends, synthetic resins, rubbers, and inks. Gasoline is about 9% xylenes by weight.246 Like toluene, xylenes causes CNS depression and can cause erythema, defatting dermatitis, conjunctivitis, renal damage, and paresthesia of the extremities. Xylene is metabolized by oxidation. It is then conjugated to methylhippuric acid and excreted in the urine. It has half-life of 20–30 hours, except in the chemically sensitive, where it may linger for weeks. Only about 5% of xylene is exhaled unchanged.
Pharmacokinetic/Physiologically Based Pharmacokinetic Models in Integrated Risk Information System Assessments
Published in John C. Lipscomb, Edward V. Ohanian, Toxicokinetics and Risk Assessment, 2016
Robert S. DeWoskin, John C. Lipscomb, Chadwick Thompson, Weihsueh A. Chiu, Paul Schlosser, Carolyn Smallwood, Jeff Swartout, Linda Teuschler, Allan Marcus
For inhalation exposures, the weight of evidence from limited human data and more extensive animal data indicate neurological impairment, and developmental effects are the most sensitive adverse effects following repeated inhalation exposure to xylenes. Reversible symptoms of neurological impairment and irritation of the eyes and throat are well-known acute effects from inhaled xylene or other aromatic solvents. In general, acute effects are expected to result from reversible molecular interactions of the parent compound (i.e., not a metabolite) with target tissue membranes, e.g., neuronal membranes, and are most pronounced at high exposure levels in excess of 1000 ppm.
Hydrocarbons*
Published in Bev-Lorraine True, Robert H. Dreisbach, Dreisbach’s HANDBOOK of POISONING, 2001
Bev-Lorraine True, Robert H. Dreisbach
Benzene: liquid; bp: 80°C; vapor pressure at 26°C: 100 mmHg; exposure limit: 1 ppm. Xylene: commercial preparation a mixture of o-, m-, p-; bp: 140°C; vapor pressure at 28°C: 10 mmHg; exposure limit: 100 ppm. Toluene: liquid; bp: 110°C; vapor pressure at 31°C: 40 mmHg; exposure limit: 100 ppm. Coal tar naphtha is a mixture of benzene, toluene, xylene, and other aromatic hydrocarbons.
Hepatotoxicological potential of P-toluic acid in humanised-liver mice investigated using simplified physiologically based pharmacokinetic models
Published in Xenobiotica, 2021
Tomonori Miura, Yusuke Kamiya, Shotaro Uehara, Norie Murayama, Makiko Shimizu, Hiroshi Suemizu, Hiroshi Yamazaki
Estimation of the human exposures to synthetic chemicals by biomonitoring is an important research area in health science (Sexton et al.2006, Alwis et al.2012). Xylenes (or dimethylbenzenes) are used as organic solvents in various industrial preparations (Lauwerys and Buchet 1988, Marchand et al.2015). In humans, the urinary excretion of xylene metabolites such as methylhippuric acid (Figure 1) has been studied in volunteers under experimental exposures and in workers under occupational exposures (Ogata et al.1970, Kawai et al.1991, Inoue et al.1993). Methylhippuric acid is biotransformed from toluic acid by glycine conjugation in rodents and humans. These glycine conjugations generally proceed in two-step reactions and are mediated by bile acid CoA:amino acid N-acyltransferase (Kwakye et al.1991, Falany et al.1997). Rodent preparations reportedly show more rapid glycine conjugation in vitro than human preparations (Kirkpatrick et al.1988, Hewitt et al.2001, Gu et al.2007). It should be noted that the no‐observed‐effect level (NOEL) of p-toluic acid in rats is high (1000 mg/kg) (Sakuratani et al.2013), possibly because of the rapid glycine conjugation of p-toluic acid and that no lowest observed effect level has been recorded in rats. Among potential animal models (including rodents), choosing the most appropriate species is relatively complex because some species may be better metabolically suited to a particular line of research than others (Wetmore et al.2010).
Examination of xylene exposure in the U.S. Population through biomonitoring: NHANES 2005–2006, 2011–2016
Published in Biomarkers, 2021
Víctor R. De Jesús, Daniel F. Milan, Young M. Yoo, Luyu Zhang, Wanzhe Zhu, Deepak Bhandari, Kevin S. Murnane, Benjamin C. Blount
Xylenes are aromatic hydrocarbons commonly used for industrial applications due to their superior solvent properties (Angerer and Lehnert, 1979, Mohammadyan and Baharfar 2015). They are synthetically derived from crude oil or coal tar and used in various commercial products such as petrochemicals, plastics, and paints. Additionally, other xylene sources in the environment include landfill gases, emissions from petroleum refineries, vehicle exhaust fumes, and tobacco smoke (Chambers et al.2011, Niaz et al.2015, Staszewska et al.2012, Saliba et al.2017). Xylene exists as three different positional isomers: ortho-, meta-, and para-xylene (o-xylene, m-xylene, and p-xylene). Throughout this report, the term xylene refers to a mixture of the three positional isomers unless otherwise stated.
Update on proteomic studies of formalin-fixed paraffin-embedded tissues
Published in Expert Review of Proteomics, 2019
Laura Giusti, Cristina Angeloni, Antonio Lucacchini
Deparaffinization is the first step in the approach with FFPE tissues and consists in the solubilization of paraffin with different apolar organic solvents or mineral oils (see [1]). Rehydration process is carried out with alcohol (methanol or ethanol) at decreasing concentration. Xylene is the apolar solvent most widely used still today, despite its toxicity, followed by rehydration with ethanol. Recently the use of efficient xylene free protocols for paraffin solubilization was proposed by three different research groups [9–11] utilizing hot water (95°, 90°, 80°C, respectively) for protein extraction or DNA extraction. The authors suggested that these protocols have the advantage to avoid toxic xylene and to perform solubilization and rehydration at the same time reducing the time of deparaffinization.