The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Britton Trabert - One of the best experts on this subject based on the ideXlab platform.
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circulating Estrogens and postmenopausal ovarian and endometrial cancer risk among current hormone users in the women s health initiative observational study
Cancer Causes & Control, 2019Co-Authors: Britton Trabert, Sally B Coburn, Roni T Falk, Joann E Manson, Louise A Brinton, Margery Gass, Lewis H Kuller, Thomas E Rohan, Ruth M PfeifferAbstract:Menopausal hormone therapy (MHT) use induces alterations in circulating Estrogens/estrogen metabolites, which may contribute to the altered risk of reproductive tract cancers among current users. Thus, the current study assessed associations between circulating Estrogens/estrogen metabolites and ovarian and endometrial cancer risk among MHT users. We conducted a nested case–control study among postmenopausal women using MHT at baseline in the Women’s Health Initiative Observational Study (179 ovarian cancers, 396 controls; 230 endometrial cancers, 253 controls). Multivariable logistic regression was utilized to estimate odds ratios and 95% confidence intervals overall and by subtype. Estrogen/estrogen metabolite levels were not associated with overall or serous ovarian cancer risk, examined separately. However, unconjugated estradiol was positively associated with non-serous ovarian cancer risk [quintile 5 vs. quintile 1: 3.01 (1.17–7.73); p-trend = 0.03; p-het < 0.01]. Endometrial cancer risk was unrelated to estrogen/estrogen metabolite levels among women who took combined estrogen/progestin therapy (EPT). These findings provide novel evidence that may support a heterogeneous hormonal etiology across ovarian cancer subtypes. Circulating Estrogens did not influence endometrial cancer risk among women with EPT-induced high-estrogen levels. Larger studies are needed to delineate the relationship between ovarian/endometrial cancer subtypes and estrogen levels in the context of MHT use.
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Comparability of serum, plasma, and urinary estrogen and estrogen metabolite measurements by sex and menopausal status
Cancer Causes & Control, 2019Co-Authors: Sally B Coburn, Roni T Falk, Louise A Brinton, Frank Z. Stanczyk, Katherine A. Mcglynn, Joshua Sampson, Gary Bradwin, Britton TrabertAbstract:Purpose The comparability between serum, plasma, and urinary measurements of estrogen metabolites via liquid chromatography–tandem mass spectrometry (LC–MS/MS) has not been largely explored, and it is unclear if urinary LC–MS/MS measurements are suitable surrogates of circulating levels. Methods Serum, plasma (EDTA and heparin), and urinary estrogen/estrogen metabolite levels were measured via LC–MS/MS in paired samples from 64 healthy volunteers (18 men, 20 premenopausal women, 26 postmenopausal women). Geometric means and Spearman correlation coefficients were used to compare individual and combined pathway levels of Estrogens/estrogen metabolites across biologic matrices by sex/menopausal status. Results Measured concentrations of Estrogens/estrogen metabolites across blood matrices were almost identical (percent differences
Wen‐chao Song - One of the best experts on this subject based on the ideXlab platform.
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Biochemistry and reproductive endocrinology of estrogen sulfotransferase.
Annals of the New York Academy of Sciences, 2006Co-Authors: Wen‐chao SongAbstract:: Estrogen sulfotransferase is a cytosolic enzyme that catalyzes the sulfoconjugation and inactivation of Estrogens. Significant progress has been made in the last few years regarding the structure, substrate specificity, tissue expression, and regulation of mammalian estrogen sulfotransferases. The enzyme has high affinity for Estrogens and is expressed in a number of estrogen target tissues, including the male and female reproductive systems. Expression of the enzyme in the testis has been particularly well characterized. In the testis, estrogen sulfotransferase is localized selectively to Leydig cells and its expression in these cells is dependent on LH and androgen. It was concluded, from both in vitro and in vivo studies, that estrogen sulfotransferase can function as an effective modulator of local estrogen activity in target tissues. The finding that certain hydroxylated polychlorinated biphenyls are potent inhibitors of the human estrogen sulfotransferase enzyme raises the possibility that environmental chemicals can cause endocrine disruption by enhancing endogenous estrogen activity through inhibition of steroid transformation enzymes such as estrogen sulfotransferase. This provides a new paradigm in explaining the endocrine disrupting potential of environmental chemicals that have low or no binding affinities for steroid hormone receptors.
Rainer Fürbass - One of the best experts on this subject based on the ideXlab platform.
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estrogen specific sulfotransferase sult1e1 in bovine placentomes inverse levels of mrna and protein in uninucleated trophoblast cells and trophoblast giant cells
Biology of Reproduction, 2014Co-Authors: Marina Polei, Torsten Viergutz, Wolfgang Tomek, Gerhard Schuler, Rainer FürbassAbstract:ABSTRACT The bovine trophoblast produces significant amounts of Estrogens. In maternal and fetal blood, Estrogens occur predominantly in sulfonated forms, which are unable to bind to estrogen receptors (ESRs). However, Estrogens may act as local factors in ESR-positive trophoblast cells or in the adjacent caruncular epithelium, which in addition to ESR highly expresses steroid sulfatase. Estrogen sulfonation is catalyzed by the cytosolic enzyme SULT1E1. Previous studies clearly indicated the trophoblast as the primary site of estrogen sulfonation. However, investigations into the cellular localization of SULT1E1 yielded conflicting results. In situ hybridization studies detected SULT1E1 mRNA only in trophoblast giant cells (TGCs), whereas in immunohistochemical experiments the SULT1E1 protein was virtually restricted to uninucleated trophoblast cells (UTCs). The aim of this work was to resolve this conflict by analyzing SULT1E1 expression in isolated UTCs and TGCs. Highly enriched pools of UTCs and TGCs w...
Regina G Ziegler - One of the best experts on this subject based on the ideXlab platform.
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urinary Estrogens and estrogen metabolites and subsequent risk of breast cancer among premenopausal women
Cancer Research, 2012Co-Authors: Heather A Eliassen, Larry K. Keefer, Timothy D. Veenstra, Donna Spiegelman, Robert L Barbieri, Walter C Willett, Susan E Hankinson, Regina G ZieglerAbstract:Endogenous Estrogens and estrogen metabolism are hypothesized to be associated with premenopausal breast cancer risk but evidence is limited. We examined 15 urinary Estrogens/estrogen metabolites and breast cancer risk among premenopausal women in a case-control study nested within the Nurses' Health Study II (NHSII). From 1996 to 1999, urine was collected from 18,521 women during the mid-luteal menstrual phase. Breast cancer cases (N = 247) diagnosed between collection and June 2005 were matched to two controls each (N = 485). Urinary estrogen metabolites were measured by liquid chromatography-tandem mass spectrometry and adjusted for creatinine level. Relative risks (RR) and 95% confidence intervals (CI) were estimated by multivariate conditional logistic regression. Higher urinary estrone and estradiol levels were strongly significantly associated with lower risk (top vs. bottom quartile RR: estrone = 0.52; 95% CI, 0.30-0.88; estradiol = 0.51; 95% CI, 0.30-0.86). Generally inverse, although nonsignificant, patterns also were observed with 2- and 4-hydroxylation pathway estrogen metabolites. Inverse associations generally were not observed with 16-pathway estrogen metabolites and a significant positive association was observed with 17-epiestriol (top vs. bottom quartile RR = 1.74; 95% CI, 1.08-2.81; P(trend) = 0.01). In addition, there was a significant increased risk with higher 16-pathway/parent estrogen metabolite ratio (comparable RR = 1.61; 95% CI, 0.99-2.62; P(trend) = 0.04). Other pathway ratios were not significantly associated with risk except parent estrogen metabolites/non-parent estrogen metabolites (comparable RR = 0.58; 95% CI, 0.35-0.96; P(trend) = 0.03). These data suggest that most mid-luteal urinary estrogen metabolite concentrations are not positively associated with breast cancer risk among premenopausal women. The inverse associations with parent estrogen metabolites and the parent estrogen metabolite/non-parent estrogen metabolite ratio suggest that women with higher urinary excretion of parent Estrogens are at lower risk.
Yuesuo Yang - One of the best experts on this subject based on the ideXlab platform.
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environmental impact of Estrogens on human animal and plant life a critical review
Environment International, 2017Co-Authors: Muhammad Adeel, Xiaoming Song, Yuanyuan Wang, Dennis Francis, Yuesuo YangAbstract:Abstract Background Since the inception of global industrialization, steroidal Estrogens have become an emerging and serious concern. Worldwide, steroid Estrogens including estrone, estradiol and estriol, pose serious threats to soil, plants, water resources and humans. Indeed, Estrogens have gained notable attention in recent years, due to their rapidly increasing concentrations in soil and water all over the world. Concern has been expressed regarding the entry of Estrogens into the human food chain which in turn relates to how plants take up and metabolism Estrogens. Objectives In this review we explore the environmental fate of Estrogens highlighting their release through effluent sources, their uptake, partitioning and physiological effects in the ecological system. We draw attention to the potential risk of intensive modern agriculture and waste disposal systems on estrogen release and their effects on human health. We also highlight their uptake and metabolism in plants. Methods We use MEDLINE and other search data bases for Estrogens in the environment from 2005 to the present, with the majority of our sources spanning the past five years. Published acceptable daily intake of Estrogens (μg/L) and predicted no effect concentrations (μg/L) are listed from published sources and used as thresholds to discuss reported levels of Estrogens in the aquatic and terrestrial environments. Global levels of Estrogens from river sources and from Waste Water Treatment Facilities have been mapped, together with transport pathways of Estrogens in plants. Results Estrogens at polluting levels have been detected at sites close to waste water treatment facilities and in groundwater at various sites globally. Estrogens at pollutant levels have been linked with breast cancer in women and prostate cancer in men. Estrogens also perturb fish physiology and can affect reproductive development in both domestic and wild animals. Treatment of plants with steroid estrogen hormones or their precursors can affect root and shoot development, flowering and germination. However, Estrogens can ameliorate the effects of other environmental stresses on the plant. Conclusions There is published evidence to establish a causal relationship between Estrogens in the environment and breast cancer. However, there are serious gaps in our knowledge about estrogen levels in the environment and a call is required for a world wide effort to provide more data on many more samples sites. Of the data available, the synthetic estrogen, ethinyl estradiol, is more persistent in the environment than natural Estrogens and may be a greater cause for environmental concern. Finally, we believe that there is an urgent requirement for inter-disciplinary studies of Estrogens in order to better understand their ecological and environmental impact.
