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#32364724   2020/05/08 To Up

Occurrence and Fate of Natural Estrogens in Swiss Cattle and Pig Slurry.

Natural estrogens act as endocrine disruptors. However, the fate of livestock farming derived natural estrogens (17α-estradiol, 17β-estradiol, estrone, and estriol) in slurry is not well understood. In this study, we assessed the effects of on farm-storage on natural estrogen concentrations in slurry. Furthermore, we monitored pig and cattle slurry pits from major agricultural areas in Switzerland and determined natural estrogen concentrations therein. They were relatively stable over time, and mean concentrations ranged from 138 to 861 and 54 to 244 ng/L for cattle and pig slurries, respectively. 17α-Estradiol and estriol were the most prevalent estrogens in cattle and pig slurries, respectively. Based on livestock numbers, agricultural area, and estrogen concentrations in slurry, the estimated annual load of total natural estrogens applied on agricultural area amounted to 36 mg/ha. Our results indicate that slurry application is a relevant source of natural estrogens in the environment.
Daniela Rechsteiner, Sabine Schrade, Michael Zähner, Michael Müller, Juliane Hollender, Thomas D Bucheli

1800 related Products with: Occurrence and Fate of Natural Estrogens in Swiss Cattle and Pig Slurry.

1,000 tests200ug11 mg1000 TESTS/0.65ml100ug50 ug 25 mg1000 tests2.5 mg100ug

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#32354868   2020/04/30 To Up

Natural estrogens enhance the engraftment of human hematopoietic stem and progenitor cells in immunodeficient mice.

Hematopoietic Stem and Progenitor Cells are crucial in the maintenance of lifelong production of all blood cells. These Stem Cells are highly regulated to maintain homeostasis through a delicate balance between quiescence, self-renewal and differentiation. However, this balance is altered during the hematopoietic recovery after Hematopoietic Stem and Progenitor Cell Transplantation. Transplantation efficacy can be limited by inadequate Hematopoietic Stem Cells number, poor homing, low level of engraftment, or limited self-renewal. As recent evidences indicate that estrogens are involved in regulating the hematopoiesis, we sought to examine whether natural estrogens (estrone or E1, estradiol or E2, estriol or E3 and estetrol or E4) modulate human Hematopoietic Stem and Progenitor Cells. Our results show that human Hematopoietic Stem and Progenitor Cell subsets express estrogen receptors, and whose signaling is activated by E2 and E4 on these cells. Additionally, these natural estrogens cause different effects on human Progenitors in vitro. We found that both E2 and E4 expand human Hematopoietic Stem and Progenitor Cells. However, E4 was the best tolerated estrogen and promoted cell cycle of human Hematopoietic Progenitors. Furthermore, we identified that E2 and, more significantly, E4 doubled human hematopoietic engraftment in immunodeficient mice without altering other Hematopoietic Stem and Progenitor Cells properties. Finally, the impact of E4 on promoting human hematopoietic engraftment in immunodeficient mice might be mediated through the regulation of mesenchymal stromal cells in the bone marrow niche. Together, our data demonstrate that E4 is well tolerated and enhances human reconstitution in immunodeficient mice, directly by modulating human Hematopoietic Progenitor properties and indirectly by interacting with the bone marrow niche. This application might have particular relevance to ameliorate the hematopoietic recovery after myeloablative conditioning, especially when limiting numbers of Hematopoietic Stem and Progenitor Cells are available.
Sara Fañanas-Baquero, Israel Orman, Federico Becerra Aparicio, Silvia Bermudez de Miguel, Jordi Garcia Merino, Rosa Yañez, Yolanda Fernandez Sainz, Rebeca Sánchez, Mercedes Dessy-Rodríguez, Omaira Alberquilla, David Alfaro, Agustin Zapata, Juan A Bueren, Jose Carlos Segovia, Oscar Quintana-Bustamante

1986 related Products with: Natural estrogens enhance the engraftment of human hematopoietic stem and progenitor cells in immunodeficient mice.

1 mg10 ug1 mg1.00 flask1.00 flask11mg0.1ml (1mg/ml)1.00 flask111.00 flask

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#32320758   2020/04/19 To Up

The 2-/16α-Hydroxylated Estrogen Ratio-Breast Cancer Risk Hypothesis: Insufficient Evidence for its Support.

During the past 25 years or so a number of studies have been carried out to address the hypothesis that the ratio of 2-hydroxyestrone (2-hydroxy-E) to 16α-hydroxyestrone (16α-hydroxy-E) is associated with breast cancer risk. The rationale for this hypothesis is based on data from studies that suggest a tumorigenic and genotoxic effect of 16α-hydroxy-E and a protective effect of 2-hydroxy-E regarding breast cancer risk. The adverse effect of 16α-hydroxy-E has been attributed to its potential to form covalent adducts with macromolecules. Initial studies used radiometric assays and enzyme immunoassays to test the hypothesis. However, concerns about the accuracy of these assays led to the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay that is capable of measuring 5 unconjugated and 15 conjugated endogenous estrogens, which include 2- and 16-hydroxylated estrogen metabolites, in serum or urine. The conjugated estrogens are quantified following a deconjugation (hydrolysis) step to remove the sulfate and glucuronide groups. Epidemiologic studies have been using the LC-MS/MS assay to determine whether there is an association between breast cancer risk and the ratio of the sum of the concentrations of metabolites in the 2-hydroxylated estrogen pathway and in the 16-hydroxylated estrogen pathway. However, the validity of the pathways as biomarkers was not evaluated. The 16-hydroxylated estrogen pathway includes estriol, 16-epiestriol, 17-epiestriol and 16-ketoestradiol, in addition to 16α-hydroxy-E. However, with the exception of 16α-hydroxy-E, there is no evidence that any of the other estrogens in the pathway have tumorigenic or genotoxic properties, and they do not form covalent adducts with macromolecules. Another deficiency in the epidemiological studies pertains to the accuracy of estrogen metabolite measurements obtained after the hydrolysis step in the LC-MS/MS assays. No validation was performed to demonstrate that a constant efficiency of hydrolysis is found for all the different structural forms of sulfated and glucuronidated conjugates. Other deficiencies in the assays include the need for greater sensitivity so that the very low concentrations of unconjugated 2-hydroxy-E, 2-hydroxy-E, and 16α-hydroxy-E can be measured in serum. There is also a need to develop assays to measure intact forms of conjugated estrogens in both serum and urine, particularly the sulfates and glucuronides of 2-hydroxylated, 2-methoxylated, and 16α-hydroxylated E and E. This will avoid inaccuracies that stem from hydrolysis procedures. Improvements in LC-MS/MS assay methodology to obtain accurate measurements of unconjugated and conjugated 2-hydroxylated, 2-methoxylated, and 16α-hydroxylated estrogen metabolites are needed. This should provide valuable data for testing the 2-/16α-hydroxylated estrogen-breast cancer risk hypothesis.
Frank Z Stanczyk

1584 related Products with: The 2-/16α-Hydroxylated Estrogen Ratio-Breast Cancer Risk Hypothesis: Insufficient Evidence for its Support.



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#32291422   // To Up

Effects of androgens and estrogens on sirtuin 1 gene expression in human aortic endothelial cells.

To investigate the effect of androgens and estrogens on surtuin 1 (SIRT1) expression in human aortic endothelial cells (HAECs).
Takafumi Tsuchiya, Ayano Takei, Kyoko Tsujikado, Toshihiko Inukai

2258 related Products with: Effects of androgens and estrogens on sirtuin 1 gene expression in human aortic endothelial cells.

1.00 flask1.00 flask1.00 flask1.00 flask1.00 flask1.00 flask300 units100ug Lyophilized5ug100ug100 μg1x10e7 cells

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