The Experts below are selected from a list of 1944 Experts worldwide ranked by ideXlab platform
Karen O Klein - One of the best experts on this subject based on the ideXlab platform.
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Ultrasensitive estrogen levels at 7 years of age predict earlier Thelarche: evidence from girls of the growth and obesity Chilean cohort.
European journal of endocrinology, 2015Co-Authors: Ana Pereira, Karen O Klein, Camila Corvalán, Ricardo Uauy, Verónica MericqAbstract:Objective: Prepubertal estradiol equivalents have been inconsistently linked to age at Thelarche; elucidating this relationship becomes relevant given the worldwide decline in the age of puberty onset. Thus, our aim is to assess whether prepubertal girls with higher serum levels of estradiol equivalents at age 7 have a greater risk of presenting early Thelarche (ET). Design: Nested case‐control study within the Growth and Obesity Cohort Study of 1196 low-middle income children (w50% girls) from Santiago, Chile. Girls were defined as cases (ET; nZ61) if breast bud appeared prior to 8 years of age; controls (nZ91) had Thelarche O8 years. Methods: At 6.7 years, weight, height and waist circumference were measured and a fasting blood sample was obtained for measuring estrogen equivalent (ultrasensitive recombinant cell bioassay), DHEAS, leptin, insulin and IGF1. Beginning at 7 years old, Tanner staging was assessed prospectively twice a year and the appearance of breast bud was assessed by palpation. Results: Mean serum estradiol-equivalent at 6.7 years was 3.9G3.6 pg/ml for cases and 3.6G2.3 pg/ml for controls. Girls with ET had a higher risk of presenting elevated estradiol-equivalent (R5 pg/ml) at 7 years (ORZ2.05, 95% CI: 0.96‐4.36) than controls that was borderline significant. However, after adjusting by BMI, insulin and IGF1 at age 7, the association between estradiol-equivalent and ET was significant (ORZ2.29 (95% CI: 1.05‐5.01)). Conclusions: Chilean girls from low to middle socioeconomic status with ETexhibited double the risk of having high levels of estradiol-equivalent at 7 years than girls with a later age of Thelarche. Whole-body adiposity and increased adrenal activity did not explain the observed prepubertal estrogen increase.
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Estrogen levels in girls with premature Thelarche compared with normal prepubertal girls as determined by an ultrasensitive recombinant cell bioassay
The Journal of pediatrics, 1999Co-Authors: Karen O Klein, Verónica Mericq, Jacquelyn M. Brown-dawson, Kimberly A. Larmore, Patricia Cabezas, Amanda CortinezAbstract:Abstract Objective: Estradiol levels in girls with premature Thelarche have not previously been well defined because of the lack of adequate sensitivity of previously available estradiol assays. The ultrasensitive recombinant cell bioassay for estradiol has made the study of estradiol levels in premature Thelarche possible. We hypothesized that girls with premature Thelarche have higher estradiol levels than normal prepubertal girls. Study design: We used an ultrasensitive recombinant cell bioassay to study estradiol levels in 20 girls with premature Thelarche and 15 normal prepubertal girls less than 3 years of age. The 2 groups were compared by Student t test. Results: Estradiol levels were significantly greater in the girls with premature Thelarche (8.4 ± 4.5 pmol/L estradiol equivalents) than in the normal prepubertal girls (3.3 ± 3.5 pmol/L estradiol equivalents; P
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Estrogen Levels in Girls with Premature Thelarche Compared to Age Matched Normal Prepubertal Girls as Determined by an Ultrasensitive Recombinant Cell Bioassay. † 395
Pediatric Research, 1997Co-Authors: Karen O Klein, Jacquelyn M Brown, Kimberly A SoissonAbstract:Estrogen Levels in Girls with Premature Thelarche Compared to Age Matched Normal Prepubertal Girls as Determined by an Ultrasensitive Recombinant Cell Bioassay. † 395
Marco A. Rivarola - One of the best experts on this subject based on the ideXlab platform.
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High serum sex hormone-binding globulin (SHBG) in premature Thelarche.
Clinical endocrinology, 1992Co-Authors: A Belgorosky, Eduardo Chaler, Marco A. RivarolaAbstract:OBJECTIVE We determined serum sex hormone-binding globulin (SHBG), serum dehydroepiandrosterone sulphate, serum oestradiol and serum testosterone and its fractions in girls with premature Thelarche. DESIGN Blood was drawn from girls with recently diagnosed (3–12 weeks) premature Thelarche. Serum was kept frozen for at least one year before hormonal determination to exclude precocious puberty by clinical evaluation. PATIENTS Seventeen girls with premature Thelarche aged 0.83–7.16 years were studied, and compared with a group of 22 normal prepubertal girls. MEASUREMENTS SHBG was measured by saturation analysis and serum dehydroepiandrosterone sulphate, serum total oestradiol and serum total testosterone were determined by radioimmunoassay. Non-SHBG-bound testosterone and free testosterone were calculated from an equation derived from the law of mass action. RESULTS Median serum SHBG in premature Thelarche was 137 nmol/l (range 64–221), significantly higher than in normal controls, 93.7 (32–172) (P < 0.05) non-parametric test of medians. Serum SHBG decreased significantly with age in controls but not in premature Thelarche. No difference was found in serum dehydroepiandrosterone sulphate. Median serum total testosterone (0.34 nmol/l, 0.17–0.97), median serum non-SHBG-bound testosterone (0.04 nmol/l, 0.02–0.10) and median free testosterone (2.2 pmol/l, 1.0–4.5) were significantly lower in premature Thelarche than in control (P < 0.001). CONCLUSIONS Serum SHBG is high and bioavailable T is low in girls with premature Thelarche. This might alter the oestrogen/androgen ratio in the breast.
Amanda Cortinez - One of the best experts on this subject based on the ideXlab platform.
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Estrogen levels in girls with premature Thelarche compared with normal prepubertal girls as determined by an ultrasensitive recombinant cell bioassay
The Journal of pediatrics, 1999Co-Authors: Karen O Klein, Verónica Mericq, Jacquelyn M. Brown-dawson, Kimberly A. Larmore, Patricia Cabezas, Amanda CortinezAbstract:Abstract Objective: Estradiol levels in girls with premature Thelarche have not previously been well defined because of the lack of adequate sensitivity of previously available estradiol assays. The ultrasensitive recombinant cell bioassay for estradiol has made the study of estradiol levels in premature Thelarche possible. We hypothesized that girls with premature Thelarche have higher estradiol levels than normal prepubertal girls. Study design: We used an ultrasensitive recombinant cell bioassay to study estradiol levels in 20 girls with premature Thelarche and 15 normal prepubertal girls less than 3 years of age. The 2 groups were compared by Student t test. Results: Estradiol levels were significantly greater in the girls with premature Thelarche (8.4 ± 4.5 pmol/L estradiol equivalents) than in the normal prepubertal girls (3.3 ± 3.5 pmol/L estradiol equivalents; P
Verónica Mericq - One of the best experts on this subject based on the ideXlab platform.
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Ultrasensitive estrogen levels at 7 years of age predict earlier Thelarche: evidence from girls of the growth and obesity Chilean cohort.
European journal of endocrinology, 2015Co-Authors: Ana Pereira, Karen O Klein, Camila Corvalán, Ricardo Uauy, Verónica MericqAbstract:Objective: Prepubertal estradiol equivalents have been inconsistently linked to age at Thelarche; elucidating this relationship becomes relevant given the worldwide decline in the age of puberty onset. Thus, our aim is to assess whether prepubertal girls with higher serum levels of estradiol equivalents at age 7 have a greater risk of presenting early Thelarche (ET). Design: Nested case‐control study within the Growth and Obesity Cohort Study of 1196 low-middle income children (w50% girls) from Santiago, Chile. Girls were defined as cases (ET; nZ61) if breast bud appeared prior to 8 years of age; controls (nZ91) had Thelarche O8 years. Methods: At 6.7 years, weight, height and waist circumference were measured and a fasting blood sample was obtained for measuring estrogen equivalent (ultrasensitive recombinant cell bioassay), DHEAS, leptin, insulin and IGF1. Beginning at 7 years old, Tanner staging was assessed prospectively twice a year and the appearance of breast bud was assessed by palpation. Results: Mean serum estradiol-equivalent at 6.7 years was 3.9G3.6 pg/ml for cases and 3.6G2.3 pg/ml for controls. Girls with ET had a higher risk of presenting elevated estradiol-equivalent (R5 pg/ml) at 7 years (ORZ2.05, 95% CI: 0.96‐4.36) than controls that was borderline significant. However, after adjusting by BMI, insulin and IGF1 at age 7, the association between estradiol-equivalent and ET was significant (ORZ2.29 (95% CI: 1.05‐5.01)). Conclusions: Chilean girls from low to middle socioeconomic status with ETexhibited double the risk of having high levels of estradiol-equivalent at 7 years than girls with a later age of Thelarche. Whole-body adiposity and increased adrenal activity did not explain the observed prepubertal estrogen increase.
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Estrogen levels in girls with premature Thelarche compared with normal prepubertal girls as determined by an ultrasensitive recombinant cell bioassay
The Journal of pediatrics, 1999Co-Authors: Karen O Klein, Verónica Mericq, Jacquelyn M. Brown-dawson, Kimberly A. Larmore, Patricia Cabezas, Amanda CortinezAbstract:Abstract Objective: Estradiol levels in girls with premature Thelarche have not previously been well defined because of the lack of adequate sensitivity of previously available estradiol assays. The ultrasensitive recombinant cell bioassay for estradiol has made the study of estradiol levels in premature Thelarche possible. We hypothesized that girls with premature Thelarche have higher estradiol levels than normal prepubertal girls. Study design: We used an ultrasensitive recombinant cell bioassay to study estradiol levels in 20 girls with premature Thelarche and 15 normal prepubertal girls less than 3 years of age. The 2 groups were compared by Student t test. Results: Estradiol levels were significantly greater in the girls with premature Thelarche (8.4 ± 4.5 pmol/L estradiol equivalents) than in the normal prepubertal girls (3.3 ± 3.5 pmol/L estradiol equivalents; P
Kimberly A Soisson - One of the best experts on this subject based on the ideXlab platform.
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Estrogen Levels in Girls with Premature Thelarche Compared to Age Matched Normal Prepubertal Girls as Determined by an Ultrasensitive Recombinant Cell Bioassay. † 395
Pediatric Research, 1997Co-Authors: Karen O Klein, Jacquelyn M Brown, Kimberly A SoissonAbstract:Estrogen Levels in Girls with Premature Thelarche Compared to Age Matched Normal Prepubertal Girls as Determined by an Ultrasensitive Recombinant Cell Bioassay. † 395
