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Urothelial and Urethral Cancer
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Ibrahim Jubber, Karl H. Pang, James W.F. Catto
Carcinogenic components are combustion products:Arylamines (particularly 4-aminobiphenol).Polycyclic aromatic hydrocarbons.N-nitroso compounds.Heterocyclic amines.Various epoxides.
Micronutrient Supplementation and Ergogenesis — Metabolic Intermediates
Published in Luke Bucci, Nutrients as Ergogenic Aids for Sports and Exercise, 2020
It was formerly believed that a reason to avoid large oral doses of DMG existed. DMG had been shown to be converted to nitrososarcosine, a weak carcinogen, in mouse stomachs.567 Nitrite presence greatly increased the amount of nitrososarcosine formed. Nitrites are present in human saliva and many preserved meat products. Another form of commercial pangamic acid, DIPA-dichloroacetate, was shown to be mutagenic by the Ames test.568 It appears that many dietary tertiary amines are being considered as nitrosatable compounds capable of causing cancer in humans. However, recent work has cast doubt on the risk of carcinogen formation from DMG.569,570 First, the risk of formation of nitroso compounds from dietary levels of DMG and similar compounds is very low (less than 1 fmol of nitrosated DMG products), even if supplemental amounts (100 mg/d) are factored.569 Second, extensive repeat experiments with more rigorous procedural controls have not found mutagenic activity from DMG reacted with nitrite.570
Experimental Lung Carcinogenesis by Intratracheal Instillation
Published in Joan Gil, Models of Lung Disease, 2020
Although N-nitroso compounds are well known to induce lung tumors when given parenterally, orally, or by inhalation, the use of N-nitrosamines for lung carcinogenicity studies using IT instillation has been limited (Dotenwill et al., 1962; Moiseev and Benemansky, 1975; IARC, graphs, 1978). Herrold and Dunham (1963), however, clearly demonstrated that IT instillation of N-nitrosodiethylamine (NDEA) induced multiple squamous cell papillomas of the trachea and bronchi and carcinomas of the ethmoid region of the nasal cavity in Syrian golden hamsters. Ferron et al. (1972) also confirmed the development of tumors in Syrian golden hamsters after IT instillation of NDEA.
A Meta-Analysis of Calcium Intake and Risk of Glioma
Published in Nutrition and Cancer, 2022
Glioma and meningioma are the two most prevalent forms of primary central nervous system tumors, accounting for more than 80% of all cases (1). Glioma is a tumor that originates from brain glial cells and is the most common in primary brain tumors (2). Gliomas have a reasonably high incidence of 4–5/100,000 persons each year, with the highest occurrence in the sixth decade of life (3, 4). Aside from ionizing radiation and some genetic abnormalities, the risk factors for brain cancer remain unknown. Furthermore, other potential risk factors include exposure to chemical carcinogens in the environment and exposure to n-nitroso compounds in dietary factors (5–7). Despite the low frequency of adult brain cancer, the prognosis for brain cancer (particularly glioma) is dismal (8). Therefore, preventing the progression of glioma has become an important strategy to prevent and treat glioma.
Investigating the root cause of N-nitrosodimethylamine formation in metformin pharmaceutical products
Published in Expert Opinion on Drug Safety, 2021
Nasr Eldin Hussein Nasr, Metwaly Gamel Metwaly, Eman Osama Ahmed, Ahmed Roshdy Fares, Aliaa Nabil ElMeshad
The term nitrosamine describes a class of compounds having the chemical structure of a nitroso group bonded to an amine (R1 N (-R2)-N = O). These compounds can be formed by a nitrosating reaction between amines (secondary, tertiary, or quaternary) and nitrous acid [1]. N-nitrosodimethyl amine (NDMA) is considered a human carcinogen according to the World Health Organization (WHO) and the International Agency for Research on Cancer [2]. The US Environmental Protection Agency found an association between NDMA and liver cancer. Also exposure to NDMA may be associated with bladder, renal, pancreatic, intestinal, colon and stomach cancers [3–6]. NDMA is mutagenic, as it transforms to diazonium ions (highly carcinogenic) by interacting with deoxyribonucleic acid (DNA), a reaction catalyzed by cytochrome P450 [7]. Figure 1 shows the chemical reactions leading finally to NDMA formation.
Cancer Chemopreventive Properties of Sulfated Enterolobium cyclocarpum Extract
Published in Nutrition and Cancer, 2021
Amira M. Gamal-Eldeen, Hassan Amer, Amani A Alrehaili, Ahmed Saleh, Abd El-Rahman Al Ghamdi, Nahed M Hawsawi, Asma Salman, Bassem M. Raafat
It is well known that N-nitroso compounds act as strong carcinogens in mammals (45). DEN has been suggested to cause oxidative stress and cellular injury due to the enhanced formation of free radicals. In rats, DEN is metabolized, primarily, in the liver by CYP into α–hydroxy derivative (ethyl-acetoxyethyl-nitrosamine) by phase I enzymes. This intermediate compound may be conjugated by phase II enzymes, which turns it into a nontoxic compound. Alternatively, this derivative may, spontaneously, produce an ethyl-diazonium ion that is able to directly ethylate the cellular macromolecules and to react with nucleophilic sites and generate DNA adducts (45). Moreover, it has been reported that the hepatocyte proliferation which was induced by a single treatment of hyperplastic agents, like DEN, supported the initiation of chemical hepatocarcinogenesis, which often identified through phenotypic markers such as GSTP. Our results found that the administration of SEC prevented DEN-induced initiation of hepatocarcinogenesis, in rats, as concluded from the remarkable inhibition of the GSTP + cells.