Sample records for cholanthrene

  1. Smoke carcinogens cause bone loss through the aryl hydrocarbon receptor and induction of CYP1 enzymes (United States)

    Smoking is a major risk factor for osteoporosis and fracture. Here, we show that smoke toxins and environmental chemicals such as benzo[a]pyrene (BaP), 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD), and 3-methyl cholanthrene, which are well known aryl hydrocarbon receptor (AHR) agonists, induce osteocla...

  2. Phytoplankton growth, dissipation, and succession in estuarine environments. Renewal proposal and annual summary report, August 1, 1977--July 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Seliger, H H


    The directions of the research program in understanding the dynamics of the natural phytoplankton populations of the Chesapeake Bay, the methodology, the statistical analysis, and the description of the system are parallel to the requirements for environmental impact studies. Results are reported for the following studies: development of instrumentation and the synoptic isopleth methodology for relating the dynamic distributions of natural phytoplankton populations to water circulation patterns; phytoplankton cage experiments for assessment of nutrient dynamics; sub-lethal concentrations and effects of polycyclic aromatic hydrocarbons; and studies on concentration and time kinetics of induction of liver aryl hydrocarbon hydroxylase system in Fundulus heteroclitus by benzopyrene and 3-methyl cholanthrene. (HLW)

  3. Safrole-DNA adducts in tissues from esophageal cancer patients: clues to areca-related esophageal carcinogenesis. (United States)

    Lee, Jang-Ming; Liu, Tsung-Yung; Wu, Deng-Chyang; Tang, Hseau-Chung; Leh, Julie; Wu, Ming-Tsang; Hsu, Hsao-Hsun; Huang, Pei-Ming; Chen, Jin-Shing; Lee, Chun-Jean; Lee, Yung-Chie


    Epidemiological studies have demonstrated that areca quid chewing can be an independent risk factor for developing esophageal cancer. However, no studies are available to elucidate the mechanisms of how areca induces carcinogenesis in the esophagus. Since the areca nut in Taiwan contains a high concentration of safrole, a well-known carcinogenic agent, we analyzed safrole-DNA adducts by the 32P-postlabelling method in tissue specimens from esophageal cancer patients. In total, we evaluated 47 patients with esophageal cancer (16 areca chewers and 31 non-chewers) who underwent esophagectomy at the National Taiwan University Hospital between 1996 and 2002. Of the individuals with a history of habitual areca chewing (14 cigarette smokers and two non-smokers), one of the tumor tissue samples and five of the normal esophageal mucosa samples were positive for safrole-DNA adducts. All patients positive for safrole-DNA adducts were also cigarette smokers. Such adducts could not be found in patients who did not chew areca, irrespective of their habits of alcohol consumption or cigarette smoking (psafrole was also tested in vitro in three esophageal cell lines and four cultures of primary esophageal keratinocytes. In two of the esophageal keratinocyte cultures, adduct formation was increased by treatment with safrole after induction of cytochrome P450 by 3-methyl-cholanthrene. This paper provides the first observation of how areca induces esophageal carcinogenesis, i.e., through the genotoxicity of safrole, a component of the areca juice.