China
Africa
Explore chapters and articles related to this topic
Interaction of Nonmodulated Radio Frequency Fields with Living Matter: Experimental Results
Published in Charles Polk, Elliot Postow, CRC Handbook of Biological Effects of Electromagnetic Fields, 2019
Two studies report effects of RF on sister chromatid exchange.81'82 In the first study, Chinese hamster ovary cells were exposed in vitro to 2.45-GHz RF at unstated power density levels and durations. Sister chromatid exchanges were observed in RF-exposed cells; however, the same level of exchanges was produced in control cells by heating them to the same temperature as that produced by RF exposure. The authors concluded that the production of sister chromatid exchanges is not related to RF. In the second study, mice were exposed to 2.45-GHz RF at 200 W/m2 (SAR 21 W/kg) for 8 hr/day for 28 days. Incidences of sister chromatid exchange in bone marrow cells of irradiated mice, sham-irradiated control mice, and standard control mice were compared. No statistically significant differences were detected.
Epidemiologic Research Priorities on the Health Risk of Drinking Water Contaminants
Published in Roberto Bertollini, Michael D. Lebowitz, Rodolfo Saracci, David A. Savitz, Environmental Epidemiology, 2019
An assessment of cancer incidence rates for the period 1955–1977 in the vicinity of the Love Canal disposal site in Niagara Falls, New York revealed elevated lung cancer that was not consistent across age groups.69 Other cancers did not appear to be elevated, but the statistical power to detect elevated rates of less common sites was limited. Rates of chromosomal aberrations and sister chromatid exchange frequencies were as expected.70 A Finnish community with drinking water contaminated with chlorophenols, probably from sawmills, had an elevated incidence of soft-tissue sarcoma and non-Hodgkin’s lymphoma.71 These tumours have been linked with exposure to the closely related chlorinated phenoxyacetic acids and/or their dioxin contaminants.72 Liver cell cancer in China was strongly linked to consuming drinking water from ditches highly polluted with agricultural runoff that presumably contained a variety of organic and other chemicals.73
Biological Monitoring of PAH Exposure
Published in Alf Bjørseth, Georg Becher, PAH in Work Atmospheres: Occurrence and Determination, 1986
These results are particularly interesting when comparing the analytical data with epidemiological data on occupational cancer in the aluminum industry. There is no obvious correlation between exposure, as measured by air analysis, and lung cancer frequency. Recent epidemiological data indicate that there is only a slight excess of lung cancer in aluminum workers, while the exposure is up to three orders of magnitude higher compared to urban atmospheres. On the other hand, analyses of PAH metabolites in urine fit well with the epidemiological data, as there is only a slight increase in the excretion of PAH in exposed workers. This corresponds well with the low or negligible increase in lung cancer found in epidemiological studies. The results are supported by the study of sister chromatid exchange (SCE) in blood lymphocytes of the same aluminum workers.48 The highly exposed workers had no significant increase in the SCE frequencies, while the SCE frequencies of cigarette smokers were significantly higher than those of the nonsmokers in both groups.
Overview of biological mechanisms of human carcinogens
Published in Journal of Toxicology and Environmental Health, Part B, 2019
Nicholas Birkett, Mustafa Al-Zoughool, Michael Bird, Robert A. Baan, Jan Zielinski, Daniel Krewski
There is strong evidence that the carcinogenicity of butadiene involves a genotoxic mechanism of action mediated by reactive epoxide metabolites. 1,3-Butadiene and its metabolites produce DNA adducts in animals and humans, with the N7 position of guanine being the major target site. The metabolites are mutagenic and genotoxic at multiple sites in mice and rats, and in a variety of other test systems. An AT-TA transversion mutation was consistently found across all biological systems. Mutations in K-Ras, H-Ras, p53, p16/p15 and β-catenin were detected in mice treated with 1,3-butadiene. Lab-controlled modulation of key determinants of 1,3-butadiene metabolism was shown to affect genotoxicity. Micronucleus formation and sister chromatid exchange were reported.
Could fluoride be considered a genotoxic chemical agent in vivo? A systematic review with meta-analysis
Published in International Journal of Environmental Health Research, 2023
Giovana Wagner Branda Drummond, Wilton Mitsunari Takeshita, Glaucia Monteiro de Castro, Jean Nunes dos Santos, Patricia Ramos Cury, Ana Claudia Muniz Renno, Daniel Araki Ribeiro
Micronucleus (MN) is an assay that identifies a chromosome or a fragment of chromosome that during mitosis was not included in the nucleus of the cell. Its size corresponds to 1/3 to 1/5 of nucleus size and is located near it. The appearance of MN is a natural process of the organism that occurs with aging itself, but exposure to xenobiotics and some diseases can increase the frequency resulting in DNA damage (Sommer et al. 2020). Comet assay (SCEG) is a method that quantifies DNA breakage. It consists in the movement of DNA fragments when subjected to electrophoresis. The lower molecular weight fragments are dragged in the anionic direction, resulting in a comet shape. The length of the tail determines the damage to the genetic material (Lu et al. 2017; Møller et al. 2020). There are two types of comet assay. The most specific is the alkaline one for detecting damage in single strands, double strands, incomplete repair regions and alkali-labile. Neutral comet assay only detects double-stranded DNA damage (Singh 2016). The sister chromatid exchange (SCE) test is able to determine the impact of clastogens effects on whole chromosomes. During the S phase of the cell cycle, occurs crossing over of genetic material between two chromatids in the same chromosome. Exposure to a genotoxic compound can lead to an increase in SCE. This technique evaluates DNA damage quantitatively and qualitatively (Wilson Iii and Thompson 2007; Kwasniewska and Bara 2020). Chromosomal aberration (ABS) test is used to identify toxic substances with the potential to induce abnormalities to chromosomes, such as chromosomal breaks or translocation of sister chromatids and thereby result in damage to genetic material, mutations, and cancer (Turkez et al. 2017).