Correlations between DNA polymorphism and frequencies of gamma-radiation induced and spontaneous cytogenetic damage

Radioactively contaminated areas: Bioindicator species and biomarkers of effect in an early warning scheme for a preliminary risk assessment

Concerns about the impacts on public health and on the natural environment have been raised regarding the full range of operational activities related to uranium mining and the rest of the nuclear fuel cycle (including nuclear accidents), nuclear tests and depleted uranium from military ammunitions. However, the environmental impacts of such activities, as well as their ecotoxicological/toxicological profile, are still poorly studied. Herein, it is discussed if organisms can be used as bioindicators of human health effects, posed by lifetime exposure to radioactively contaminated areas. To do so, information was gathered from several studies performed on vertebrates, invertebrate species and humans, living in these contaminated areas. The retrieved information was compared, to determine which are the most used bioindicators and biomarkers and also the similarities between human and non-human biota responses. The data evaluated are used to support the proposal for an early warning scheme, based on bioindicator species and on the most sensitive and commonly shared biomarkers, to perform a screening evaluation of radioactively contaminated sites. This scheme could be used to support decision-making for a deeper evaluation of risks to human health, making it possible to screen a large number of areas, without disturbing and alarming local populations.

Time in hemodialysis modulates the levels of genetic damage in hemodialysis patients

It is assumed that hemodialysis treatment can diminish the levels of genetic damage in circulating lymphocytes by cleaning the blood of uremic toxins that cause oxidative stress. However, the hemodialysis process by itself may also induce genomic damage by producing reactive oxygen species (ROS). We conducted a follow-up study in a group of 70 hemodialysis patients followed for a mean time of 15 months. We investigated the effect of exposure time in hemodialysis on the levels of genetic damage in peripheral blood lymphocytes using the micronucleus assay. In addition, genetic damage after in vitro irradiation with 0.5 Gy was also analyzed to evaluate changes in radiosensitivity. Our results showed that, at the end of the study, there was a decrease in both the basal levels of genetic damage (9.9 ± 1.0 vs. 7.6 ± 0.7) and radiosensitivity values (38.5 ± 3.0 vs. 27.6 ± 2.4). We conclude that hemodialysis procedures may act as an ameliorating factor reducing the genetic damage present in chronic kidney disease patients.

Association of single nucleotide polymorphisms in ERCC2 gene and their haplotypes with esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC), one of the leading causes of cancer death worldwide, occurs at a relatively high frequency in China. To investigate whether common excision repair cross-complementing rodent repair group 2 (ERCC2) variants (rs3916874 G>C, rs238415 C>G, rs1618536 G>A, rs1799793 G>A, and rsl3181 A>C) were associated with ESCC risk, a case-control study was conducted, including 405 cases with ESCC and 405 age and sex 1:1 matched cancer-free controls. The result showed that rsl3181 AC/CC genotypes was associated with an increased risk of ESCC (OR: 1.45, 95% CI: 1.05-2.00), and two ERCC2 haplotypes Grs3916874Crs238415Grs1618536Grs1799793Crsl3181 (Hap5) and Grs3916874Grs238415Ars1618536Grs1799793Crsl3181 (Hap7) were associated with increased risk of ESCC (OR: 2.16, 95 % CI: 1.27-3.57 for Hap5 and OR: 3.72; 95 % CI: 1.89-6.63 for Hap7, respectively), while Grs3916874Grs238415Grs1618536Grs1799793Arsl3181 (Hap4) was associated with decreased risk of ESCC (OR: 0.47, 95% CI: 0.35-0.71). Gene-environment interaction analysis by multifactor dimensionality reduction (MDR) software showed that there was an interaction among rs238415, rs1618536, and family history of cancer with a P value under 0.0001 (OR: 3.23: 95% CI: 2.37-4.40). These results suggested that genetic variations in the ERCC2 gene were associated with risk of ESCC, and there was a significant interaction between gene polymorphisms and family history of cancer in the etiology of ESCC.