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7,12-Dimethylbenz[a]anthracene
About: 7,12-Dimethylbenz[a]anthracene is a research topic. Over the lifetime, 1717 publications have been published within this topic receiving 40892 citations.
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TL;DR: It is suggested that SAC exerts its chemopreventive effects by modulating lipid peroxidation and enhancing antioxidant activities in the target organ as well as in the liver and circulation.
Abstract: The effect of S-allylcysteine (SAC), a water-soluble garlic constituent, on 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis was investigated in male Syrian hamstes. Forty hamsters were divided into 4 groups of 10 animals. The right buccal pouches of the animals in Group I were painted with a 0.5% solution of DMBA in liquid paraffin three times a week. The animals in Group II were painted with DMBA as in Group I and, in addition, received 200 mg/kg body wt p.o. SAC three times a week on days alternate to DMBA application. Group III animals received SAC as in Group II. Group IV animals received neither DMBA nor SAC and served as the control. The hamsters were killed after an experimental period of 14 wk. Measurement of lipid peroxidation, the antioxidant enzymes superoxide dismutase (SOD) and catalase, in the buccal pouch mucosa, liver, and circulation was used to monitor the chemopreventive potential of SAC. All hamsters painted with DMBA alone developed tumors identified histologically as well-differentiated squamous cell carcinomas. In hamsters bearing DMBA-induced buccal pouch tumors, diminished lipid peroxidation in the tumor tissue was accompanied by decreased activities of SOD and catalase, whereas in the liver and circulation, enhanced lipid peroxidation was associated with compromised antioxidant defenses. Administration of SAC suppressed the incidence of DMBA-induced HBP tumors as revealed by the absence of carcinomas. Histologically, only keratosis was observed. SAC modulated DMBA-induced decreased susceptibility of the HBP to lipid peroxidation while simultaneously enhancing SOD and catalase activities, whereas in the liver and circulation, SAC decreased the extent of lipid peroxidation and significantly enhanced antioxidant activities. We suggest that SAC exerts its chemopreventive effects by modulating lipid peroxidation and enhancing antioxidant activities in the target organ as well as in the liver and circulation.
25 citations
TL;DR: A calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) markedly inhibited the promoting activity of teleocidin on formation of skin tumors in mice initiated by 7,12-dimethylbenz[a]anthracene, indicating that the critical action of the Ca2+-calmodulin system is responsible for tumor promotion in mouse skin.
Abstract: A calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) markedly inhibited the promoting activity of teleocidin on formation of skin tumors in mice initiated by 7,12-dimethylbenz[a]anthracene. This result strongly indicates that the critical action of the Ca2+-calmodulin system is responsible for tumor promotion in mouse skin.
25 citations
TL;DR: The absence of an absolute increase in 6-sulfatoxymelatonin after DMBA could be caused by an additional shift within the spectrum of different metabolic products of melatonin due to the carcinogen.
Abstract: The aim of this study was to establish whether the nocturnal peak concentrations of circulating melatonin are affected by a single dose of 7,12-dimethylbenz[a]anthracene (DMBA) in female Sprague-Dawle
25 citations
TL;DR: The results from this study in combination with previous data suggest that the chemopreventive effects of GLN are exerted by enhancing the antioxidant status of the body and activation of apoptosis.
25 citations
TL;DR: It is shown that iron overload acts as a mild tumor promoter in mouse skin and oxidative stress generated by iron overload plays an important role in the augmentation of cutaneous tumorigenesis.
Abstract: SummaryIron overload is known to occur in West European and American populations due to the consumption of an iron-rich diet. There are also genetic disorders which lead to body iron overload. It has been shown that iron overload predisposes humans to an increased risk of cancer. In experimental animals, iron overload is known to enhance intestinal, colon, hepatic, pulmonary and mammary carcinogenesis. However, the mechanism by which iron overload enhances chemically-induced carcinogenesis is not known. In this study, we show that iron overload acts as a mild tumor promoter in mouse skin. Female albino swiss mice were given 1 mg iron/mouse parenterally for 2 weeks to induce iron overload. These animals showed a three-fold increase in cutaneous iron concentration as compared to normal mice. Tumors were initiated by topically applying 7,12-dimethylbenz(a)anthracene (DMBA). Appearance of the first tumor (latency period), percent tumor incidence and number of tumors/mouse were recorded. When compared to the c...
25 citations