Identification of carcinogens by measurement of cell-mediated immunity: I. Immunity induced by rat pancreas and colon carcinogens

Anti-tumor cell-mediated immunity was used as a measure of exposure to chemical carcinogens. The measurements involved determining the amount of cytotoxicity to cultured X-ray-induced rat small bowel adenocarcinoma cells exhibited by peripheral blood lymphoid-cells isolated from animals exposed to the carcinogens. Cytotoxicity was determined by the release of radioiodinated integral and peripheral proteins of the small bowel cancer cells. The studies indicate that exposures to 1,2-dimethylhydrazine (DMH) which induces colon adenocarcinomas and 7,12-dimethylbenz[a]anthracene (DMBA) implants which produce pancreatic adenocarcinomas, can be detected within a 6- to 72-day postexposure interval. Dose response studies of the DMH indicate exposures to as little as 100 μg (1.7 μmol) can be detected within this time interval although this amount is insufficient to produce detectable cancer. The present results further outline the specificity of the assay since it was found that tumors of mesodermally derived tissues (asbestos-induced peritoneal mesotheliomas) and nonspecific injury (70% surgical resection of ileum and jejunum) will not induce cytotoxicity. Our previous studies had shown ectodermal lesions also will not evoke responses; therefore, these findings suggest the measured anti-tumor immunity is specific to carcinogens which interact with entodermally derived tissue. Thus, the findings support our suggestion that measurement of anti-tumor immunity offers a rapid, sensitive, and specific technique for detecting carcinogenic substances.     

Chemical and radioactive carcinogens in cigarettes: associated health impacts and responses of the tobacco industry, U.S. Congress, and federal regulatory agencies

21?Po and 21?Pb were discovered in tobacco in 1964. This was followed by detailed assessments of the nature of their deposition, and accompanying dose rates to the lungs of cigarette smokers. Subsequent studies revealed: (1) the sources and pathways through which they gain access to tobacco; (2) the mechanisms through which they preferentially deposit in key segments of the bronchial epithelium; and (3) the fact that the accompanying alpha radiation plays a synergistic role in combination with the chemical carcinogens, to increase the fatal cancer risk coefficient in cigarette smokers by a factor of 8 to 25. Nonetheless, it was not until 2009 that Congress mandated that the Food and Drug Administration require that the cigarette industry reveal the presence of these carcinogens. In the meantime, cigarette smoking has become not only the number one source of cancer deaths in the United States, but also a major contributor to heart disease and other health impacts. If the latter effects are included, smoking is estimated to have caused an average of 443,000 deaths and 5.1 million years of potential life lost among the U.S. population each year from 2000 through 2004. The estimated associated collective dose is more than 36 times that to the workers at all the U.S. nuclear power plants, U.S. Department of Energy nuclear weapons facilities, and crews of all the vessels in the U.S. Nuclear Navy. This unnecessary source of lung cancer deaths demands the utmost attention of the radiation protection and public health professions.     

The structure,role, and procedures of the U.S. Advisory Committee on Immunization Practices (ACIP)

The National Immunization Technical Advisory Group (NITAG) in the United States is the Advisory Committee on Immunization Practices (ACIP). The ACIP was established in 1964 by the US Surgeon General to assist in the prevention and control of communicable diseases, and includes a chair, an executive secretary, 15 voting members, 8 ex officio members and liaison representatives from 26 health-related professional organizations. Meetings are regularly convened at the Centers for Disease Control and Prevention (CDC) and are open to the public. Stringent measures and rigorous screening are used to avoid both real and apparent conflicts of interest, and no special interest or lobbying groups provide any material support to ACIP or its members. The committee recommends licensed new vaccines to be incorporated into the routine immunization schedule, recommends vaccine formulations, and reviews older vaccines to consider revising its recommendations.