4- tumorigenic activities

It is not appropriate to generali2e the carcinogenicity of this class of compounds. Nitrofura2one appears to increase the incidence of benign mammary tumors in rats. The tumorigenic activity of fura2ohdone is expressed by an increase in the incidence of spontaneous tumors in both mice and rats. Bioassays of nitrofurantoin in several species of mice and rats failed to reveal any evidence of direct tumorigenic activity. Ovarian tumors have been reported in B C F mice, but these are beheved due to an indirect expression of toxicity (14,15). 

Some laboratory studies with rats and mice have linked trichloroethylene exposure to various types of cancers. Several of these studies, however, should be viewed cautiously, since the tumorigenic activity might be influenced by the presence of direct-acting compounds, namely the epoxides (e.g., epichlorohydrin) added as stabilizers in trichloroethylene. Epoxides are known to be very reactive, and some, such as epichlorohydrin, are potent carcinogens themselves. 

Carcinogenesis research has demonstrated the tumorigenic activities of a large number of chemical substances in experimental animals. These include molecules of diverse chemical classes, organic and inorganic, and natural products as well as compounds synthesized in the laboratory or produced by industry. 

Importantly, knowledge of intestinal bile acid transport and metabolism, coupled with increased understanding of the mechanistic basis of the pro-tumorigenic activity of bile acids against CRC cells in vitro, has recently led to development and testing of bile acid-based treatment and prevention strategies for sporadic and inflammatory bowel-disease-associated CRC. Existing evidence that manipulation of the luminal secondary bile acid pool and/or therapy with ursodeoxycholic acid (UDCA) may have promise for prevention of CRC will be assessed. 

There are three main sources of evidence for pro-tumorigenic activity of bile acids in the lower gastro-intestinal tract (activity in rodent CRC models, human observational data and mechanistic studies using CRC cells in vitro), which together create a strong case for a role for colorectal mucosal bile acid exposure during human colorectal carcinogenesis. 

AAF is classified as a cytotoxic teratogen. Because of demonstrated carcinogenicity in animals, contact by all routes should be avoided. In recent years this compound has been used only in laboratories as a model of tumorigenic activity in animals. It is of little occupational health importance. 

In humans, a concentration of 330ppm caused slight irritation of the eyes and rapidly increasing nasal irritation. No chronic systemic effects have been reported in humans. Rats survived 4 hours of inhalation at 4000 ppm, but 8000 ppm was fatal to five of six animals. Cats exposed to 5000 ppm for 20 minutes showed eye irritation 10,000 ppm for 80 minutes caused narcosis followed by death. Pulmonary edema and death were observed in dogs exposed to 10,000 ppm for 4 hours. When applied to the skin of mice, ethyl formate showed no evidence of tumorigenic activity in 10 weeks. ... 

NTl29 LaVoie, E. J., G. Prokopczyk, J. Rigotty, A. Czech, A. Rivenson, and J. D. Adams. Tumorigenic activity of the tobacco-specific nitrosamines 4-(methyl-ni trosam ino) -1 - (3 -py r idy 1) -1 -butanone (NNK), 4-(methylnitrosamino)-4-(3-pyridyl)- -butanol (iso-NNAL) and N -nitrosonomicotine (NNN) on topical application to Senear mice. Cancer Lett 1987 37(3) 277-283. 

Another health hazard associated with exposure to UV radiation is the potential cocarcinogenic activity of UV light with the contaminant on the skin. Past studies have found that exposure to UV radiation results in a significant enhancement of the effects of chemical carcinogens such as 7,12-dimethyl benzanthracene (13) and benzo[a]pyrene (14). Even normally innocuous compounds such as anthracene, n-decane and n-tetradecane can develop tumorigenic activity in mice under irradiation with long-wavelength (>350 nm)... 

Jeong, J. Kamino, K. (1993) Lack of tumorigenic activity of 1.1-dimethyIhydrazine in Syrian... 

Furst A, Schlauder M, Sasmore DP. 1976. Tumorigenic activity of lead chromate. Cancer Res 36 1779-1783. 

Continued studies from several laboratories of the binding, mutagenicity and tumorigenicity of benzo [a] pyrene and its derivatives led to the identification of (+)-(7R,8S)-dihydroxy-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[aJpyrene (a diol epoxide-2 diastereomer) as the principal metabolite responsible for the carcinogenic activity of benzo[a]pyrene. Only one of the four metabolically possible isomers of the 7,8-diol-9,10-epoxide was found to have high tumorigenic activity... 

Several compounds, such as creatinine and purine derivatives (allantoin, uric acid, hypoxanthine, and xanthine) present in biological samples, are important analytes for diagnoses of certain types of metabolic diseases and can serve as markers for these processes. Analyses for such substances are crucial for the diagnosis and monitoring of renal diseases, metabolic disorders, and various types of tumorigenic activity. 

Repeated exposures to APFO, the most widely used salt of PFOA, produced liver, kidney, pancreas and testes changes, anemia, and cyanosis. Tests in male rats demonstrated weak tumorigenic activity based on an increased incidence of benign testicular, pancreatic, and liver tumors. Tests in animals demonstrate no developmental toxicity. 

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