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Vitamin D is not really a vitamin but the precursor to the potent steroid hormone calcitriol, which has widespread actions throughout the body. Calcitriol regulates numerous cellular pathways that could have a role in determining cancer risk and prognosis. Although epidemiological and early clinical trials are inconsistent, and randomized control trials in humans do not yet exist to conclusively support a beneficial role for vitamin D, accumulating results from preclinical and some clinical studies strongly suggest that vitamin D deficiency increases the risk of developing cancer and that avoiding deficiency and adding vitamin D supplements might be an economical and safe way to reduce cancer incidence and improve cancer prognosis and outcome.
In studies to determine whether Saccharomyces cerevisiae produced estrogens, the organism was grown in culture media prepared using distilled water autoclaved in polycarbonate flasks. The yeast-conditioned media showed the presence of a substance that competed with [3H]estradiol for binding to estrogen receptors (ER) from rat uterus. However, it soon became clear that the estrogenic substance in the conditioned media was not a product of the yeast grown in culture, but was leached out of the polycarbonate flasks during the autoclaving procedure. [3H]Estradiol displacement activity was monitored by ER RRA, and the active substance was purified from autoclaved medium using a series of HPLC steps. The final purified product was identified as bisphenol-A (BPA) by nuclear magnetic resonance spectroscopy and mass spectrometry. BPA could also be identified in distilled water autoclaved in polycarbonate flasks without the requirement of either the organism or the constituents of the culture medium. Authentic BPA was active in competitive RRAs, demonstrating an affinity approximately 1:2000 that of estradiol for ER. In functional assays, BPA (10-25 nM) induced progesterone receptors in cultured human mammary cancer cells (MCF-7) at a potency of approximately 1:5000 compared to that of estradiol. The BPA effect on PR induction was blocked by tamoxifen. In addition, BPA (25 nM) increased the rate of proliferation of MCF-7 cells assessed by [3H]thymidine incorporation. Thus, BPA exhibited estrogenic activity by both RRA and two functional bioresponse assays. Finally, MCF-7 cells grown in media prepared with water autoclaved in polycarbonate exhibited higher progesterone receptor levels than cells.grown in media prepared with water autoclaved in glass, suggesting an estrogenic effect of the water autoclaved in polycarbonate. Our findings raise the possibility that unsuspected estrogenic activity in the form of BPA may have an impact on experiments employing media autoclaved in polycarbonate flasks. It remains to be determined whether BPA derived from consumer products manufactured from polycarbonate could significantly contribute to the pool of estrogenic substances in the environment.
BackgroundWe hypothesized that a fully automated mobile health (mHealth) intervention with tracking and texting components would increase physical activity.Methods and Results mActive enrolled smartphone users aged 18 to 69 years at an ambulatory cardiology center in Baltimore, Maryland. We used sequential randomization to evaluate the intervention's 2 core components. After establishing baseline activity during a blinded run‐in (week 1), in phase I (weeks 2 to 3), we randomized 2:1 to unblinded versus blinded tracking. Unblinding allowed continuous access to activity data through a smartphone interface. In phase II (weeks 4 to 5), we randomized unblinded participants 1:1 to smart texts versus no texts. Smart texts provided smartphone‐delivered coaching 3 times/day aimed at individual encouragement and fostering feedback loops by a fully automated, physician‐written, theory‐based algorithm using real‐time activity data and 16 personal factors with a 10 000 steps/day goal. Forty‐eight outpatients (46% women, 21% nonwhite) enrolled with a mean±SD age of 58±8 years, body mass index of 31±6 kg/m2, and baseline activity of 9670±4350 steps/day. Daily activity data capture was 97.4%. The phase I change in activity was nonsignificantly higher in unblinded participants versus blinded controls by 1024 daily steps (95% confidence interval [CI], −580 to 2628; P=0.21). In phase II, participants receiving texts increased their daily steps over those not receiving texts by 2534 (95% CI, 1318 to 3750; P<0.001) and over blinded controls by 3376 (95% CI, 1951 to 4801; P<0.001).ConclusionsAn automated tracking‐texting intervention increased physical activity with, but not without, the texting component. These results support new mHealth tracking technologies as facilitators in need of behavior change drivers.Clinical Trial Registration URL: http://ClinicalTrials.gov/. Unique identifier: NCT01917812.
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