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diethylstilbestrol diethylstilbestrol [keywords]
- Nylon 6 electrospun nanofibers mat as effective sorbent for the removal of estrogens: kinetic and thermodynamic studies. [Journal Article]
- Nanoscale Res Lett 2014; 9(1):353.
Nylon 6 electrospun nanofibers mat was prepared via electrospinning for the removal of three estrogens, namely, diethylstilbestrol (DES), dienestrol (DS), and hexestrol (HEX) from aqueous solution. Static adsorption as well as the dynamic adsorption was evaluated by means of batch and dynamic disk flow mode, respectively. The kinetic study indicated that the adsorption of the target compounds could be well fitted by the pseudo-second-order equation, suggesting the intra-particle/membrane diffusion process as the rate-limiting step of the adsorption process. The adsorption equilibrium data were all fitted well to the Freundlich isotherm models, with a maximum adsorption capacity values in the range of 97.71 to 208.95 mg/g, which can be compared to or moderately higher than other sorbents published in the literatures. The dynamic disk mode studies indicated that the mean removal yields of three model estrogens were over 95% with a notable smaller amount of adsorbent (4 mg). Thermodynamic study revealed that the adsorption process was exothermic and spontaneous in nature. Desorption results showed that the adsorption capacity can remain up to 80% after seven times usage. It was suggested that Nylon 6 electrospun nanofibers mat has great potential as a novel effective sorbent material for estrogens removal.
- Effect of ethanolic extract of Lepidium meyenii Walp on serum hormone levels in ovariectomized rats. [Journal Article]
- Indian J Pharmacol 2014 Jul; 46(4):416-9.
To evaluate the effect of long-term ethanol extract of Lepidium meyenii (Maca) on serum hormone levels in ovariectomized (OVX) rats and compare them with the effect of diethylstilbestrol.Fifty female Sprague-Dawley rats were ovariectomized or sham operated. Both sham and OVX control groups (n = 10, respectively) received the vehicle. The remaining OVX rats were oral administrated with ethanol extract of Maca (0.096, or 0.24g/kg; n = 10, respectively) and diethylstilbestrol (0.05 mg/kg; n = 10). The treatment continued for 28 weeks. At week 12 and week 28, the blood of rats was collected and serum hormone levels, including estradiol (E2), testosterone (T) and follicle-stimulating hormone (FSH) were measured by radioimmunoassay.At week 12, the levels of serum E2 were slightly higher in Maca groups than that in OVX group; T levels were significantly decreased; and FSH levels were advanced slightly in Maca groups than that in sham group. After 28 weeks administration, serum E2 levels in Maca-treated animals did not differ significantly from sham control, the low dose of Maca increased serum E2 levels, and Maca prevented increase in serum FSH levels compared with OVX group.Long-term Maca supply modulates endocrine hormone balance in OVX rats, especially it decreases enhanced FSH levels. It is proposed that Maca may become a potential choice for postmenopausal women.
- A time-resolved fluorescence immunoassay for the ultrasensitive determination of diethylstilbestrol based on the double-codified gold nanoparticles. [JOURNAL ARTICLE]
- Steroids 2014 Aug 1.
An ultrasensitive and selective method is presented for the determination of diethylstilbestrol (DES) using time-resolved fluorescence immunoassay (TRFIA) based on double-codified gold nanoparticles (DC-AuNPs). In this system, the DC-AuNPs, that are gold nanoparticles (AuNPs) modified with anti-DES antibody and SH-dsDNA-biotin, was regarded as signal amplifier. A competitive immunoreaction was performed on polystyrene microtitration plates, where the DES compete with the immobilized DES-ovalbumin on polystyrene microtitration plates to bind to anti-DES antibodies on DC-AuNPs, and the europium(III)-labeled streptavidin was added to link to the SH-dsDNA-biotin as a tracer. Fluorescence signal was amplified via the AuNPs and the biotin-streptavidin double amplification systems. Under the optimized condition, DES can be quantified by TRFIA. The linear range and the limit of detection of DES were 1.0×10(-6)-10ngmL(-1) and 0.4fgmL(-1), respectively. This method was applied to determine DES in beef sample, with the recoveries ranging from 88% to 105%.
- Histone methyl-transferase EZH2 is transcriptionally induced by estradiol as well as estrogenic endocrine disruptors bisphenol-A and diethylstilbesterol. [JOURNAL ARTICLE]
- J Mol Biol 2014 Jul 31.
Enhancer of Zeste homolog 2 (EZH2), a histone 3 lysine 27 (H3K27) specific methyltransferase, is a critical player in gene silencing and is overexpressed in breast cancer. Our studies demonstrate that EZH2 is transcriptionally induced by estradiol in cultured breast cancer cells as well as in the mammary glands of ovariectomized rats. EZH2 promoter contains multiple functional estrogen-response elements (EREs). Estrogen-receptors (ERs) and ER-coregulators such as MLL-histone methylases (MLL2 and MLL3) and histone acetyl-transferase CBP/P300 bind to the EZH2 promoter in presence of estradiol and regulate estradiol-induced EZH2 expression. EZH2 expression is also increased upon exposure to estrogenic endocrine disrupting chemicals such as bisphenol-A (BPA) and diethylstilbestrol (DES). Similar to estradiol, BPA and DES-induced EZH2 expression is coordinated by ERs, MLLs and CBP/P300. In summary, we demonstrate that EZH2 is transcriptionally regulated by estradiol in vitro and in vivo, and its expression is potentially dysregulated upon exposure to estrogenic endocrine disrupting chemicals.
- Timing and recovery of postweaning exposure to diethylstilbestrol on early pregnancy in CD-1 mice. [JOURNAL ARTICLE]
- Reprod Toxicol 2014 Jul 22.:48-54.
Exposure timing could play an important role in the effects of estrogenic endocrine disrupting chemicals (EEDCs) on early pregnancy. This study examined the sensitivity of different exposure periods from weaning to gestation day 4.5 (D4.5) to 50ppb diethylstilbestrol (DES, a test EEDC) diet on embryo implantation and potential recovery upon temporary cessation of DES exposure in CD-1 mice. Peripubertal (3-5 weeks old) DES exposure reduced the numbers of corpora lutea and implantation sites. Postpubertal (5-7 weeks old) DES exposure did not have significant effects on early pregnancy. Postmating (D0.5-D4.5) DES exposure affected postovulation events leading to impaired embryo implantation. A 5-day premating rest from 5-week DES exposure (3-8 weeks old) resulted in recovery of early pregnancy rate. These data demonstrate that peripubertal and postmating periods are sensitive windows to endocrine disruption of early pregnancy and temporary cessation of exposure could partially alleviate adverse effects of DES on early pregnancy.
- Structural insights into selective agonist actions of tamoxifen on human estrogen receptor alpha. [Journal Article]
- J Mol Model 2014 Aug; 20(8):2338.
Tamoxifen-an anti-estrogenic ligand in breast tissues used as a first-line treatment in estrogen receptor (ER)-positive breast cancers-is associated with the development of resistance followed by resumption of tumor growth in about 30 % of cases. Whether tamoxifen assists in proliferation in such cases or whether any ligand-independent pathway to transcription exists is not fully understood; also, no ERα mutants have been detected so far that could lead to tamoxifen resistance. Using in silico conformational analysis of the ERα ligand binding domain (LBD), in the absence and presence of selective agonist (diethylstilbestrol; DES), antagonist (Faslodex; ICI), and selective estrogen receptor modulator (SERM; 4-hydroxy tamoxifen; 4-OHT) ligands, we have elucidated ligand-responsive structural modulations of the ERα-LBD dimer in its agonist and antagonist complexes to address the issue of "tamoxifen resistance". DES and ICI were found to stabilize the dimer in their agonist and antagonist conformations, respectively. The ERα-LBD dimer without the presence of any bound ligand also led to a stable structure in agonist conformation. However, binding of 4-OHT to the antagonist structure led to a flexible conformation allowing the protein to visit conformations populated by agonists as was evident from principal component analysis and radius of gyration plots. Further, the relaxed conformations of the 4-OHT bound protein exhibited a diminished size of the co-repressor binding pocket in the LBD, thus signaling a partial blockage of the co-repressor binding motif. Thus, the ability of 4-OHT-bound ERα-LBD to assume flexible conformations visited by agonists and reduced co-repressor binding surface at the LBD provide crucial structural insights into tamoxifen-resistance that complement our existing understanding.
- Efficacy of kidney-tonifying traditional Chinese medicine prescriptions in hypoplastic uterus treatment: A systematic review and meta-analysis. [Journal Article]
- J Obstet Gynaecol Res 2014 Jul; 40(7):1913-24.
To review and evaluate the efficacy of kidney-tonifying traditional Chinese medicine prescriptions (KT-TCMP) in hypoplastic uterus (HU) treatment.We searched MEDLINE, the Cochrane Library, CNKI (China National Knowledge Infrastructure), WANFANG and VIP databases until 14 December 2013 independently with two investigators. Randomized controlled trials (RCT) involving KT-TCMP as a combined or monotherapy in the treatment of HU were reviewed and analyzed. Meta-analysis was performed by Review Manager (version 5.2).Nine RCT of 1745 patients were eligible for this review and meta-analysis, of which eight RCT described the primary outcome of clinical efficacy and three RCT drew the secondary outcome of uterine size. Meta-analyzed 'recovery' clinical efficacy of KT-TCMP in seven RCT was conducted which considered diethylstilbestrol therapy alone as control, as well as three RCT that meta-analyzed the effect of KT-TCMP on uterine diameter enlargement. As a result, KT-TCMP therapy had a significantly improved difference in increasing 'recovery' clinical efficacy (risk ratio, 2.34; 95% confidence interval [CI], 1.90-2.89) and enlarging the uterine diameter (standardized mean difference, 1.62; 95% CI, 1.39-1.84). One study reported adverse reactions as an important outcome and found it was safe during KT-TCMP therapy.The therapy of applying KT-TCMP as a combined or monotherapy in the treatment of HU may be more efficacious. However, these RCT were of moderate methodological quality and small sample size; thus, the results should be confirmed with more rigorously controlled further studies.
- Endocrine Disruption Screening by Protein and Gene Expression of Vitellogenin in Freshly Isolated and Cryopreserved Rainbow Trout Hepatocytes. [JOURNAL ARTICLE]
- Chem Res Toxicol 2014 Jul 23.
Xenobiotics may activate the estrogen receptor, resulting in alteration of normal endocrine functions in animals and humans. Consequently, this necessitates development of assay end points capable of identifying estrogenic xenobiotics. In the present study, we screened the potential estrogenicity of chemicals via their ability to induce vitellogenin (VTG) expression in cultured primary hepatocytes from male trout. A routine method for VTG detection measures the secretion of the protein by enzyme-linked immunosorbent assay (ELISA) in freshly isolated trout hepatocytes. However, this lengthy (6 days) culturing procedure requires that hepatocyte isolation is performed each time the assay is run. We optimized this methodology by investigating the utility of cryopreserved hepatocytes, shortening the incubation time, performing a quantitative real-time PCR (qPCR) method for VTG quantification, and verifying the model system with reference chemicals 17β-estradiol, estrone, diethylstilbestrol, hexestrol, genistein, and a negative control, corticosterone. To test the performance of both freshly isolated and cryopreserved hepatocytes, mRNA was collected from hepatocytes following 24 h treatment for VTG gene expression analysis, whereas cell culture media was collected for a VTG ELISA 96 h post-treatment. EC50 values were obtained for each reference chemical except for corticosterone, which exhibited no induction of VTG gene or protein level. Our results show linear concordance between ELISA and qPCR detection methods. Although there was approximately 50% reduction in VTG inducibility following cryopreservation, linear concordance of EC50 values was found between freshly isolated and cryopreserved hepatocytes, indicating that cryopreservation does not alter the functional assessment of estrogen receptor activation and therefore VTG expression. These studies demonstrate that qPCR is a sensitive and specific method for detecting VTG gene expression that can be used together with cryopreserved trout hepatocytes for screening estrogenic chemicals, resulting in a reduction of the time required to perform the assay and enabling greater access to the model system through the approach of cryopreservation.
- Vitellogenin of the northern leopard frog (Rana pipiens): Development of an ELISA assay and evaluation of induction after immersion in xenobiotic estrogens. [Journal Article]
- Chemosphere 2014 Oct.:348-54.
An immunoassay for leopard frog (Rana pipiens) vitellogenin was developed for studying endocrine disruption. Male frogs were injected with estradiol-17β to stimulate vitellogenin for purification. SDS-PAGE revealed high amounts of a 170-180kDa protein, which was confirmed to be vitellogenin by Western blotting. Vitellogenin was purified by DEAE chromatography and used to generate a polyclonal antibody. A competitive ELISA was developed for leopard frog vitellogenin with a detection limit of 6.0ngmL(-1) and a working range of 20-1000ngmL(-1). The intra-assay coefficient of variation averaged 5.47% for control sera and 9.71% for estrogen-treated sera. The inter-assay coefficient of variation averaged 8.21% for control sera and 9.93% for estrogen-treated sera. Recovery of purified vitellogenin averaged 95.2%. Vitellogenin was measured in male frogs immersed in the estrogenic compound diethylstilbestrol (DES) for various times and doses. Serum vitellogenin was detected within five days after immersion in 1.0mgL(-1) DES and levels continued to increase through 20d. In a 20-day dose-response experiment, serum vitellogenin was detected in frogs immersed in 0.01mgL(-1) DES and vitellogenin concentration increased with dose. Immersion of frogs in one of several xenobiotic estrogens (nonylphenol, octylphenol, bisphenol-A) for 20d did not increase vitellogenin for any treatment, suggesting that this frog may be less sensitive than fish to endocrine disruptors. Vitellogenin induction in R.pipiens may be a useful amphibian model system for field studies of endocrine disruption, due to its broad geographic range.
- A novel ERα-mediated reporter gene assay for screening estrogenic/antiestrogenic chemicals based on LLC-MK2 cells. [JOURNAL ARTICLE]
- Toxicol Mech Methods 2014 Jul 21.:1-14.
Abstract Low concentration of endocrine disrupting chemicals (EDCs) may lead to serious consequences in animals and human, so it is essential to develop an effective assay for EDCs detection. In this study, we developed a novel ERα-mediated reporter gene assay based on LLC-MK2 cells by co-transfecting pERE-sv40-Luc, hERα-pcDNA3.1 and pRL-tk. Then we determined 17β-estradiol (E2) and some estrogenic/antiestrogenic chemicals to verify the validity of this assay. Data showed that the assay possess a concentration-dependent responses to E2, diethylstilbestrol (DES) from 10(-12)M to 10(-8)M with EC50 3.4×10(-10)M and 5.9×10(-10)M respectively and ICI 182,780 completely block the luciferase activity induced by 10(-9)M E2. Bisphenol A (BPA), nonylphenol (NP), genistein (GS) and tamoxifen (TAM) also showed corresponding estrogenic or antiestrogenic activity at test concentrations. All evidences proved that the LLC-MK2 reporter gene assay was specific and sensitive to estrogen receptor (ER) agonistic and antagonistic chemicals.