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Estradiol Concentrations (estradiol + concentration)

Distribution by Scientific Domains

Medical Sciences	62%

Selected Abstracts

Low Skeletal Muscle Mass Is Associated With Poor Structural Parameters of Bone and Impaired Balance in Elderly Men,The MINOS Study,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2005
Pawel Szulc MD
Abstract In 796 men, 50-85 years of age, decreased relative skeletal muscle mass index was associated with narrower bones, thinner cortices, and a consequent decreased bending strength (lower section modulus), as well as with impaired balance and an increased risk of falls. Introduction: In men, appendicular skeletal muscle mass (ASM) is correlated positively with BMC and areal BMD (aBMD). In elderly men, low muscle mass and strength (sarcopenia) is associated with difficulties in daily living activities. The aim of this study was to evaluate if ASM is correlated with bone size, mechanical properties of bones, balance, and risk of falls in elderly men. Materials and Methods: This study used 796 men, 50-85 years of age, belonging to the MINOS cohort. Lifestyle factors were evaluated by standardized questionnaires. Estimates of mechanical bone properties were derived from aBMD measured by DXA. ASM was estimated by DXA. The relative skeletal muscle mass index (RASM) was calculated as ASM/(body height)2.3. Results: After adjustment for age, body size, tobacco smoking, professional physical activity, and 17,-estradiol concentration, RASM was correlated positively with BMC, aBMD, external diameter, and cortical thickness (r = 0.17-0.34, p < 0.0001) but not with volumetric BMD. Consequently, RASM was correlated with section modulus (r = 0.29-0.39, p < 0.0001). Men in the lowest quartile of RASM had section modulus of femoral neck and distal radius lower by 12-18% in comparison with men in the highest quartile of RASM. In contrast, bone width was not correlated with fat mass, reflecting the load of body weight (except for L3), which suggests that the muscular strain may exert a direct stimulatory effect on periosteal apposition. After adjustment for confounding variables, a decrease in RASM was associated with increased risk of falls and of inability to accomplish clinical tests of muscle strength, static balance, and dynamic balance (odds ratio per 1 SD decrease in RASM, 1.31-2.23; p < 0.05-0.001). Conclusions: In elderly men, decreased RASM is associated with narrower bones and thinner cortices, which results in a lower bending strength. Low RASM is associated with impaired balance and with an increased risk of falls in elderly men. It remains to be studied whether low RASM is associated with decreased periosteal apposition and with increased fracture risk in elderly men, and whether the difference in skeletal muscle mass between men and women contributes to the between-sex difference in fracture incidence. [source]

Ovarian stromal blood flow following clomiphene citrate challenge test in infertile women

JOURNAL OF CLINICAL ULTRASOUND, Issue 7 2008
Ernest Hung Yu Ng MD
Abstract Purpose. To compare ovarian stromal blood flow indices in the follicular phase and after clomiphene citrate (CC) in infertile women. Methods. Pulsatility index (PI), resistance index (RI), and peak systolic blood flow velocity (PSV) of ovarian stromal vessels were determined by spectral Doppler analysis in the early follicular phase and on day 10 after CC. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol concentrations were determined. Results. A total of 69 infertile women were included in the analysis. No significant differences in the average PI, RI, and PSV of ovarian stromal blood flow were demonstrated in the follicular phase and after CC despite a significant increase in serum estradiol concentration after CC. Serum FSH concentration was similar in the follicular phase and after CC, while serum LH concentration was significantly higher after CC. In the right ovary, ovarian stromal blood flow was absent in 13 (18.8%) patients in the follicular phase and in 6 (8.7%) patients after CC, but the difference did not reach statistical significance. In the left ovary, ovarian stromal blood flow was absent in 13 (18.8%) and 12 (17.4%) patients in the follicular phase and after CC, respectively. Conclusion. Ovarian stromal blood flow indices were similar in the follicular phase and after CC. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008 [source]

Sublethal effects of methylmercury on fecal metabolites of testosterone, estradiol, and corticosterone in captive juvenile white ibises (Eudocimus albus),

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2009
Evan M. Adams
Abstract Methylmercury (MeHg) is a globally distributed neurotoxin, endocrine disruptor, and teratogen, and its effects on birds are poorly understood, especially within an environmentally relevant exposure range. In an effort to understand the potential causal relationship between MeHg exposure and endocrine development, we established four dietary exposure groups (0 [control], 0.05, 0.1, and 0.3 mg/kg wet wt/d of MeHg) of postfledging white ibises (Eudocimus albus) in a divided, free-flight aviary that spanned the estimated range of environmental exposure for this species. Fecal samples were collected from individually identified ibises over six months in 2005 and processed for hormone evaluation. Significant sex-related differences in fecal estradiol concentrations, though unpredicted in direction, suggest that this steroid could be related to juvenile development in this species. Using repeated-measures general linear models, we tested a set of candidate models to explain variation in endocrine expression. We found that MeHg exposure led to significant differences in fecal estradiol concentrations between the control and medium-dose groups, whereas differences in fecal corticosterone concentrations were observed between the control and both the low- and high-dose groups. These results suggest highly nonlinear dose-response patterns for MeHg. Many endocrine-disrupting contaminants are theorized to affect multiple endpoints in a nonlinear manner, making results difficult to interpret using a traditional toxicological approach. The evidence presented here suggests that endocrine effects of MeHg exposure could behave similarly. [source]

Evaluation of the methoxytriazine herbicide prometon using a short-term fathead minnow reproduction test and a suite of in vitro bioassays

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2006
Daniel L. Villeneuve
Abstract Prometon is one of the most consistently detected herbicides in the U.S. environment. However, no previous assessment of the potential for prometon or related methoxytriazine herbicides to act as endocrine-disrupting chemicals has been conducted. This study used an array of in vitro bioassays to assess whether prometon, atraton, terbumeton, or secbumeton might act as potent (ant)agonists of the aryl hydrocarbon, estrogen, androgen, or glucocorticoid receptors or as aromatase inhibitors or inducers in vitro. Potential effects of prometon were also evaluated using a 21-d fathead minnow reproduction assay. Concentrations of methoxytriazines, as great as 1 mg/L (4.4 ,M), did not induce significant dioxin-like responses in H4IIE-luc cells, estrogenic responses in MVLN cells, or androgen or glucocorticoid receptor,mediated responses in MDA-kb2 cells, nor did the methoxytriazines significantly affect aromatase activity in vitro. In the fathead minnow assay, exposure to 20, 200, or 1,000 ,g prometon/L significantly reduced the weight of the male fat pad (an androgen-responsive tissue) relative to body weight. Exposure to 20 ,g prometon/L significantly increased female plasma testosterone concentrations, but the effect was not observed at greater concentrations. Overall, prometon did not significantly reduce fecundity over the 21-d exposure, nor were other endpoints, including plasma vitellogenin and estradiol concentrations, brain and ovary aromatase activity, and male tubercle index, significantly affected. Evidence from our work suggests that prometon may cause subtle endocrine and/or reproductive effects in fathead minnows, but no clear mechanism of action was observed. The relevance of these effects to hazard assessment for the pesticide is uncertain. [source]

Association Between Testosterone and Estradiol and Age-Related Decline in Physical Function in a Diverse Sample of Men

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2008
Andre B. Araujo PhD
OBJECTIVES: To examine the association between aging and physical function in men by testing a theoretically based model of aging, hormones, body composition, strength, and physical function with data obtained from men enrolled in the Boston Area Community Health/Bone (BACH/Bone) Survey. DESIGN: Cross-sectional, observational survey. SETTING: Population-based. PARTICIPANTS: Eight hundred ten black, Hispanic, and white randomly selected men from the Boston area aged 30 to 79. MEASUREMENTS: Testosterone, estradiol, sex hormone,binding globulin, lean and fat mass, grip strength, and summated index of physical function (derived from walk and chair stand tests). RESULTS: Measures of grip strength and physical function declined strongly with age. For instance, 10 years of aging was associated with a 0.49-point difference (scale 0,7) in physical function. Age differences in total testosterone and estradiol concentrations were smaller than age differences in their free fractions. Weak or nonsignificant age-adjusted correlations were observed between hormones and measures of physical function, although path analysis revealed a positive association between testosterone and appendicular lean mass and a strong negative association between testosterone and total fat mass. Lean and fat mass, in turn, were strongly associated with grip strength and physical function, indicating the possibility that testosterone influences physical function via indirect associations with body composition. CONCLUSION: The age-related decline in serum testosterone concentration in men has a weak association with physical strength and functional outcomes through its associations with lean and fat mass. [source]

Ovarian stromal blood flow following clomiphene citrate challenge test in infertile women

Polymers effect on estradiol partition coefficient between powdered human stratum corneum and water

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2002
Ronald C. Wester
Abstract Macromolecules have gained interest as drug entities unto themselves and as transport facilitators to alter initial phases of percutaneous absorption. Two macromolecular polymers (MW 2081 and 2565) were designed to hold cosmetics and drugs to the skin surface by altering initial chemical and skin partitioning. The effect of these polymers on the partition coefficient (PC) of estradiol with powdered human stratum corneum (PHSC) and water was determined. There was no statistically significant effect on the PC when the concentration of estradiol was increased 100-fold (0.028,2.8 ,g/mL), when the incubation time was increased from 0 to 24 h, or when PHSC was delipidized. The addition of a liphophilic polymer had no effect on the PC; however, the hydrophilic polymer showed a significant polymer concentration-dependent increase (p,<,0.01) in log PC for estradiol concentrations. Thus, a macromolecular chemical has the potential to alter the partitioning of chemical into the outer layers of skin, the first step in percutaneous absorption. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2642,2645, 2002 [source]

Menopausal asthma: a new biological phenotype?

ALLERGY, Issue 10 2010
M. P. Foschino Barbaro
To cite this article: Foschino Barbaro MP, Costa VR, Resta O, Prato R, Spanevello A, Palladino GP, Martinelli D, Carpagnano GE. Menopausal asthma: a new biological phenotype? Allergy 2010; 65: 1306,1312. Abstract Background:, Female hormones play an important role in women's lung health, especially in asthma pathophysiology. Although a growing interest has recently been aroused in asthma related to short-term reproductive states, menopausal asthma has been little studied in the past. The aim of the present study was to explore airway inflammation in menopausal asthmatic women in a noninvasive manner. Methods:, Forty consecutive women with menopausal asthma, 35 consecutive women with premenopausal asthma and 30 age-matched healthy controls were enrolled in the study. Urinary LTE-4, induced sputum inflammatory cells, and exhaled LTE-4, IL-6, pH, and NO levels were measured in all the subjects enrolled. Results:, Women with menopausal asthma showed decreased estradiol concentrations, high sputum neutrophils, and exhaled IL-6. Women with premenopausal asthma presented instead an essentially eosinophilic inflammatory pattern. Higher urine and breath condensate LTE-4 concentrations were found in premenopausal and menopausal asthma compared to controls. Conclusion:, Our results substantiate the existence of a new biological phenotype of menopausal asthma that is mainly characterized by neutrophilic airways inflammation and shares several characteristics of the severe asthma phenotype. [source]