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Xu C.,Nanjing Medical University | Liu Q.,Nanjing Medical University | Liu H.,Nanjing Medical University | Heroux P.,InVitroPlus Laboratory | And 4 more authors.
PLoS ONE | Year: 2015

Background: Little is known regarding the effects of environmental exposure of chemicals on androgenic system in the general population. We studied 5,107 subjects included in the National Health and Nutrition Examination Survey (2011-2012). Methods: Urinary, serum, and blood levels of 15 subclasses comprising 110 individual chemicals were analyzed for their association with serum testosterone levels. The subjects were divided into high and low testosterone groups according to the median testosterone concentration (374.51 ng/dL). Odds ratios (ORs) of individual chemicals in association with testosterone were estimated using logistic regression after adjusting for age, ethnicity, cotinine, body mass index, creatinine, alcohol, and the poverty income ratio. Results: Adjusted ORs for the highest versus lowest quartiles of exposure were 2.12 (95% CI: 1.07, 4.21; Ptrend= 0.044), 1.84 (95% CI: 1.02, 3.34; Ptrend= 0.018) for the association between urinary mandelic acid, and strontium quartiles with low testosterone concentrations in adult men, respectively. However, no association was observed for the remaining chemicals with testosterone. Conclusions: The National Health and Nutrition Examination Survey data suggest that elevations in urinary mandelic acid, and strontium levels are negatively related to low serum testosterone levels in adult men. © 2015 Xu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Li Y.,InVitroPlus Laboratory | Li Y.,McGill University | Heroux P.,InVitroPlus Laboratory | Heroux P.,McGill University | Kyrychenko I.,Cell Culture Technologies
Tumor Biology | Year: 2012

The metabolism of cultured cancer cells is stimulated by 21% oxygen and generous nutrition, while real tumors grow in oxygen and nutrient-restricted environments. The effect of these contrasted conditions was studied in five hyperploid (54-69) cancer cell lines. When grown under anoxia and in the presence of antioxidant metabolic restrictors, the cell lines quickly reverted to almost normal chromosome numbers (47-49). The stepped withdrawal of oxygen over K562 showed progressive increases in proliferation rate and the acquisition of a stable, stem phenotype. In genetic studies, hyperploid cancer cells adjusted their chromosome numbers up or down to match their micro-environment through rapid mechanisms of endo-reduplication or chromosome loss. These fast reactions may explain the surprising adaptability of tumor cells to oncologic interventions. Furthermore, karyotype contraction may provide a basis for the previously observed carcinogenic influence of the administration of some antioxidants in human populations. © 2011 International Society of Oncology and BioMarkers (ISOBM). Source

Li Y.,InVitroPlus Laboratory | Li Y.,McGill University | Heroux P.,InVitroPlus Laboratory | Heroux P.,McGill University
Electromagnetic Biology and Medicine | Year: 2014

Background: Biological effects of extra-low-frequency (ELF) magnetic fields (MFs) have lacked a credible mechanism of interaction between MFs and living material. Objectives: To examine the effect of ELF-MFs on cancer cells. Methods: Five cancer cell lines were exposed to ELF-MFs within the range of 0.025-5 μT, and the cells were examined for karyotype changes after 6 d. Results: All cancer cells lines lost chromosomes from MF exposure, with a mostly flat dose-response. Constant MF exposures for three weeks allow a rising return to the baseline, unperturbed karyotypes. From this point, small MF increases or decreases are again capable of inducing karyotype contractions (KCs). Our data suggest that the KCs are caused by MF interference with mitochondria's adenosine triphosphate synthase (ATPS), compensated by the action of adenosine monophosphate-activated protein kinase (AMPK). The effects of MFs are similar to those of the ATPS inhibitor, oligomycin. They are amplified by metformin, an AMPK stimulator, and attenuated by resistin, an AMPK inhibitor. Over environmental MFs, KCs of various cancer cell lines show exceptionally wide and flat dose-responses, except for those of erythroleukemia cells, which display a progressive rise from 0.025 to 0.4 μT. Conclusions: The biological effects of MFs are connected to an alteration in the structure of water that impedes the flux of protons in ATPS channels. These results may be environmentally important, in view of the central roles played in human physiology by ATPS and AMPK, particularly in their links to diabetes, cancer and longevity. © 2014 Informa Healthcare USA, Inc. Source

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