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Adverse Reactions to Local Anesthetics
Published in Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand, Pediatric Regional Anesthesia, 2019
Gari Purcell-Jones, Felicity Reynolds
Methemoglobinemia is a well-recognized effect of local anesthetics. It is periodically reported following surface application and ingestion of benzocaine, and less frequently with lidocaine.238–241 Nowadays it is most commonly encountered following prilocaine administration. The causative agent is O-toluidine, a product of prilocaine hydrolysis (see Section III, Chapter 1).
Nasal Cavity Carcinogens: Possible Routes of Metabolic Activation
Published in D. V. M. Gerd Reznik, Sherman F. Stinson, Nasal Tumors in Animals and Man, 2017
Stephen S. Hecht, Andre Castonguay, Dietrich Hoffmann
Many aromatic amines are activated by formation of hydroxamic acid esters or hydroxylamines which dissociate to electrophilic nitrenium ions that react with DNA.88,89 It is likely that the metabolic activation of p-cresidine involves N-oxidation. In the metabolism of o-toluidine, N-oxidation is a relatively minor pathway, but the resulting metabolites are mutagenic toward S. typhimurium.90,91 The major metabolites of o-toluidine in vivo in the rat result from oxidation of the para position and conjugation. This is probably a detoxification process. Oxidation at the para position of p-cresidine might be inhibited by the neighboring methyl group. This could result in a relatively greater proportion ofN-oxidation. The activity in the nasal cavity mucosa for conjugation of metabolites of aromatic amines could be a major factor in their carcinogenicity, but no relevant studies have been performed.
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
Aromatic and heterocyclic amines are chemicals composed of single- and multiple-ring systems with an exocytic amino group. They do not occur in nature except for complex heterocyclines that are generated during pyrolysis. They are synthetics used in dye and drug manufacturing and as antioxidants.383 The typical monoarylamines and polyarylamines with carcinogenic potential include aniline and o-toluidine (sarcoma), o-anisidine and p-cresidine (bladder cancer), and phenacetin384 (Table 5.48). At high doses, anilines are carcinogenic, and through its metabolite phenylhydroxylamine, aniline is a powerful hematopoietic poison producing methemoglobinemia. o-Toluidine and 2,6-dimethylaniline are released from the local anesthetics prilocaine and lidocaine.385 High-level chronic abuse, but not ordinary intermittent drug use, of phenacetin has led to human bladder cancer.386 These aforementioned aromatic amines have been observed to trigger chemical sensitivity.
Pea Starch-Lauric Acid Complex Alleviates Dextran Sulfate Sodium-Induced Colitis in C57BL/6J Mice
Published in Nutrition and Cancer, 2023
Nina Qin, Yan Meng, Zhihua Ma, Zhaoping Li, Zhenzhen Hu, Chenyi Zhang, Liyong Chen
Pea starch was purchased from Yantai Shuangta Company (Yantai, China). Lauric acid and anhydrous ethanol were purchased from Sinopharm Group (Beijing, China). Pullulanase was purchased from Aladdin (Shanghai, China). The resistant starch detection kit was purchased from Megazyme (Wicklow, Ireland). DSS (molecular weight 36–50 KDa) was purchased from MP Biomedicals (Solon, USA). A fecal occult blood qualitative test kit (O-toluidine method) was purchased from Leagene Biotechnology (Beijing, China). Hematoxylin and eosin (H&E) staining and immunohistochemical detection kits were purchased from Servicebio (Wuhan, China). Enzyme-linked immunosorbent assay (ELISA) kits for the detection of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were purchased from Solarbio (Beijing, China). The RNAeasy™ Animal RNA Isolation Kit with Spin Column was purchased from Beyotime Biotechnology (Shanghai, China). The M5 Sprint qPCR RT kit with gDNA remover and M5 HiPer SYBR Premix EsTaq (with Tli RNaseH) were purchased from Mei Biotechnology (Beijing, China). RIPA Lysis Buffer, phenylmethanesulfonyl fluoride, and a dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) kits were purchased from Beyotime Biotechnology (Shanghai, China). Antibodies against Occludin and claudin-1 were purchased from Abcam (Cambridge, UK). Antibodies against mucin 2 (MUC2) and zonula occludens-1 (ZO-1) were purchased from Servicebio (Wuhan, China). Rabbit- and mouse-derived antibodies were purchased from ZSGB Biotechnology (Beijing, China).
Development of reliable quantitative structure–toxicity relationship models for toxicity prediction of benzene derivatives using semiempirical descriptors
Published in Toxicology Mechanisms and Methods, 2023
Ayushi Singh, Sunil Kumar, Archana Kapoor, Parvin Kumar, Ashwani Kumar
The AD was studied using William’s plot. There were total of 12 compounds falling outside the domain of applicability. Nonylphenol, Pentafluoroaniline, 2,4,6-and Tris(dimethyIaminomethyI)phenol lie beyond the cut off HAT value (h* = 0.0476). 4-Hexylresorcinol, 1-Bromo-2,4-dinitrobenzene, 1-Chloro-2,4-dinitrobenzene, 2,3,4,5-Tetrachlorophenol, 4-Chloro-3,5-dinitrobenzonitrile, and α,α,α-4-Tetrafluoro-o-toluidine were response outliers only. Compound Pentafluoronitrobenzene, 1,5-DifIuoro-2,4-dinitrobenzene, and Pentafluorobenzyl alcohol were found to be structural as well as response outliers. Further, the full model QSTR model had the same AD as that of this split model.
A comprehensive review of cytochrome P450 2E1 for xenobiotic metabolism
Published in Drug Metabolism Reviews, 2019
Jingxuan Chen, Sibo Jiang, Jin Wang, Jwala Renukuntla, Suman Sirimulla, Jianjun Chen
Prilocaine and lidocaine are safe in general but induce methemoglobinemia occasionally by O-toluidine and 2,6-xylidine, the hydrolysis products of prilocaine and lidocaine. Incubation with an anti-CYP2E1 antibody was reported to decrease methemoglobin formation induced by O-toluidine and 2,6-xylidine. In addition to CYP2E1, CYP3A4 and human carboxylesterase are also involved in the production of these metabolites. CYP2E1 further hydrolyzes the metabolites of prilocaine and lidocaine to 4- and 6-hydroxy-o-toluidine and 4-hydroxy-2, 6-xylidine, respectively, efficiently increasing methemoglobin formation, which results in methemoglobinemia (Higuchi et al. 2013).