ᮀ Low-dose ionizing radiation (LDR) may lead to suppression of smoking-related lung cancer. We examined the effects of a known cigarette smoke carcinogen Benzo[a]pyrene (B[a]P) alone or in combination with fractionated low-dose gamma radiation (60 -600 mGy total dose) on the induction of lung neoplasms in the A/J mouse. Our results show that 600 mGy of gamma radiation delivered in six biweekly fractions of 100 mGy starting 1 month after B[a]P injection significantly inhibits the development of lung adenomas per animal induced by B[a]P. Our data also indicated that the six biweekly doses suppressed the occurrence of spontaneous hyperplastic foci in the lung, although this suppression failed to reach statistical significance when analyzed as average foci per lung possibly related to the small sample sizes used for the control and test groups.
American Indian/Alaska Native (AI/AN) and Canadian Indigenous people are disproportionally affected by hepatitis C virus (HCV) infection yet are frequently underrepresented in epidemiologic studies and surveys often used to inform public health efforts. We performed a systematic review of published and unpublished literature and summarized our findings on HCV prevalence in these Indigenous populations. We found a disparity of epidemiologic literature of HCV prevalence among AI/AN in the United States and Indigenous people in Canada. The limited data available, which date from 1995, demonstrate a wide range of HCV prevalence in AI/AN (1.49%–67.60%) and Indigenous populations (2.28%–90.24%). The highest HCV prevalence in both countries was reported in studies that either included or specifically targeted people who inject drugs. Lower prevalence was reported in studies of general Indigenous populations, although in Canada, the lowest prevalence was up to 3-fold higher in Aboriginal people compared with general population estimates. The disparity of available data on HCV prevalence and need for consistent and enhanced HCV surveillance and reporting among Indigenous people are highlighted. HCV affects Indigenous peoples to a greater degree than the general population; thus we recommend tribal and community leaders be engaged in enhanced surveillance efforts and that funds benefitting all Indigenous persons be expanded to help prevent and cover health care expenses to help stop this epidemic.
ᮀ We show evidence for low doses of γ rays preventing spontaneous hyperplastic foci and adenomas in the lungs of mice, presumably via activating natural anticancer defenses. The evidence partly relates to a new study we conducted whereby a small number of female A/J mice received 6 biweekly dose fractions (100 mGy per fraction) of γ rays to the total body which prevented the occurrence of spontaneous hyperplastic foci in the lung. We also analyzed data from a much earlier Oak Ridge National Laboratory study involving more than 10,000 female RFMf/Un mice whereby single γ-ray doses from 100 to 1,000 mGy prevented spontaneous lung adenomas. We point out the possibility that the decrease in lung cancer mortality observed in The National Lung Screening Trial Research Team study involving lung tumor screening using low-dose computed tomography (CT) may relate at least in part to low-dose X-rays activating the body's natural anticancer defenses (i.e., radiation hormesis). This possibility was apparently not recognized by the indicated research team.
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