The effects of 50 Hz magnetic field-exposed cell culture medium on cellular functions in FL cells.

Although extremely low frequency magnetic fields (ELF-MFs) have been classified as a possible carcinogen for humans by the International Agency for Research on Cancer (IARC), their biological effects and underlying mechanisms are still unclear. Our previous study indicated that ELF-MF exposure influenced the relative permittivity of the saline solution, suggesting that the MF exposure altered physical properties of the solution. To explore the biophysical mechanism of ELF-MF-induced biological effects, this study examined the effects of 50 Hz sinusoidal MF at 0-4.0 mT on the permittivity of culture medium with phase-interrogation surface plasmon resonance (SPR) sensing. Then, the biological effects of MF pre-exposed culture medium on cell viability, the mitogen-activated protein kinase (MAPK) signaling pathways, oxidative stress, and genetic stabilities were analyzed using Cell Counting Kit-8, western blot, flow cytometry, γH2AX foci formation, and comet assay. The results showed that SPR signals were decreased under MF exposure in a time- and dose-dependent manner, and the decreased SPR signals were reversible when the exposure was drawn off. However, MF pre-exposed culture medium did not significantly change cell viability, intracellular reactive oxygen species level, activation of the MARK signaling pathways, or genetic stabilities in human amniotic epithelial cells (FL cells). In conclusion, our data suggest that the relative permittivity of culture medium was influenced by 50 Hz MF exposure, but this change did not affect the biological processes in FL cells.

Association between parental occupational exposure to extremely low frequency magnetic fields and childhood nervous system tumors risk: A meta-analysis.

BACKGROUND AND OBJECTIVE: Previous epidemiological studies suggested association between parental occupational exposure to extremely low frequency magnetic fields (ELF-MF) and risk of childhood nervous system tumors, but the results were inconsistent. We conducted a meta-analysis of case-control and cohort studies to re-evaluate this association. METHODS: Relevant studies were identified by searching PubMed and Web of Science databases as well as by manual searching. Summary odds ratio (OR) with 95% confidence interval (CI) were pooled with a fixed-effects or random-effects model. RESULTS: A total of 22 eligible articles (21 case-control studies and 1 cohort study) were included for the quantitative analysis. The results showed that parental occupational ELF-MF exposure was significantly associated with an increased risk of childhood nervous system tumors (OR = 1.11, 95% CI = 1.02-1.21), and this association remained in studies on central nervous system (CNS) tumors (OR = 1.13, 95% CI = 1.02-1.27) but not neuroblastoma (OR = 1.02, 95% CI = 0.92-1.14). Furthermore, maternal (OR = 1.14, 95% CI = 1.05-1.23) but not paternal (OR = 1.05, 95% CI = 0.98-1.13) occupational ELF-MF exposure significantly increased risk of childhood nervous system tumors. Increased risk of childhood CNS tumors was significant associated with maternal (OR = 1.16, 95% CI = 1.06-1.26) but not paternal (OR = 1.15, 95% CI = 0.98-1.34) occupational ELF-MF exposure. CONCLUSION: In conclusion, our results provide limited evidence for the association between maternal occupational exposure to ELF-MF and increased risk of childhood CNS tumors, which should be explained with cautions. Future studies are needed to further evaluate the association of paternal occupational ELF-MF exposure with risk of childhood CNS tumors.

Associations of urinary polycyclic aromatic hydrocarbons with bone mass density and osteoporosis in U.S. adults, NHANES 2005-2010.

Polycyclic aromatic hydrocarbons (PAHs) are environmental endocrine disruptors, which may modify the bone mineralization. However, epidemiological evidences on this issue were scant. We aimed to investigate the associations of PAHs with bone mass density (BMD) and osteoporosis based on a nationally-representative sample from general U.S. POPULATION: Data utilized were extracted from the 2005-2010 National Health and Nutrition Examination Survey (NHANES). Nine urinary PAHs (U-PAHs) metabolites were measured as exposure biomarkers. Associations of specific U-PAHs with BMD and osteoporosis were estimated by multivariable adjusted linear regression models and logistic regression models, respectively. Compared with women at the first tertiles, those at the third tertiles of 1-Hydroxynapthalene, 2-Hydroxyfluorene, 3-Hydroxyphenanthrene, 2-Hydroxyphenanthrene and 9-Hydroxyfluorene had significantly decreased BMD levels [coefficient (ß) = -0.023 to -0.014, p < 0.05] or increased likelihoods of osteoporosis [odds ratios (ORs) = 1.86 to 3.36, p < 0.05] at different bone sites. Whereas, elevated BMD levels (ß = 0.021, p < 0.05) at trochanter and decreased likelihoods of osteoporosis (OR = 0.33, p < 0.05) at intertrochanter were observed among women at the second tertiles of 1-Hydroxypyrene and 2-Hydroxynapthalene, respectively. Similar results were found for all the population, i.e., combination of men and women. Most of the significant associations disappeared among adult men only. Furthermore, Associations between U-PAHs and BMD were stronger for postmenopausal women when compared with premenopausal group. In conclusion, associations of U-PAHs with BMD and osteoporosis varied by specific U-PAHs and bone sites, as well as menopausal status and genders in U.S. adults.