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Jon D Hennebold - One of the best experts on this subject based on the ideXlab platform.
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impact of the prostaglandin synthase 2 inhibitor celecoxib on ovulation and luteal events in women
Contraception, 2013Co-Authors: Alison Edelman, Jeffrey T Jensen, Carmen M Doom, Jon D HenneboldAbstract:Abstract Background Ovarian prostaglandins are critical in normal ovulation processes; thus, their inhibition may provide contraceptive benefits. This study was performed to determine the effect of the cyclooxygenase-2 (COX2) inhibitor celecoxib on ovulation and luteal events in women. Study Design The study had a randomized, double-blind, crossover design. Ovulatory, reproductive-aged women underwent ovarian ultrasound and serum hormone monitoring during four menstrual Cycles (Control Cycle, treatment Cycle 1, washout Cycle, treatment Cycle 2). Subjects received study drug (oral celecoxib 400 mg or placebo) either (a) once daily starting on Cycle day 8 and continuing until follicle rupture or the onset of next menses if follicle rupture did not occur [pre-luteinizing hormone (LH) surge dosing] or (b) once daily beginning with the LH surge and continuing for 6 days (post-LH surge dosing). Subjects were randomly assigned to one of the above treatment schemes and received the other in the subsequent treatment Cycle. The main outcomes were evidence of ovulatory and luteal dysfunction as determined by inhibited/delayed follicle rupture and reduced luteal progesterone synthesis or lifespan, respectively. Results A total of 20 women enrolled and completed the study (Group 1=10, Group 2=10), with similar demographics between groups. Nineteen subjects exhibited normal ovulation in the Control Cycle (one had a blunted LH peak). In comparison to Control Cycles, treatment Cycles resulted in a significant increase in ovulatory dysfunction [pre-LH treatment: 30% (6/20), p=.04; post-LH treatment: 25% (5/20), p=.04]. Mean peak progesterone, estradiol, and LH levels and luteal phase length did not differ significantly between Control and either treatment Cycle. Conclusions Although treatment with celecoxib before or after the LH surge increases the rate of ovulatory dysfunction, most women ovulate normally. Thus, this selective COX2 inhibitor appears to be of limited usefulness as a potential emergency contraceptive.
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original research article impact of the prostaglandin synthase 2 inhibitor celecoxib on ovulation and luteal events in women
2013Co-Authors: Alison Edelman, Jeffrey T Jensen, Carmen M Doom, Jon D HenneboldAbstract:Background: Ovarian prostaglandins are critical in normal ovulation processes; thus, their inhibition may provide contraceptive benefits. This study was performed to determine the effect of the cyclooxygenase-2 (COX2) inhibitor celecoxib on ovulation and luteal events in women. Study Design: The study had a randomized, double-blind, crossover design. Ovulatory, reproductive-aged women underwent ovarian ultrasound and serum hormone monitoring during four menstrual Cycles (Control Cycle, treatment Cycle 1, washout Cycle, treatment Cycle 2). Subjects received study drug (oral celecoxib 400 mg or placebo) either (a) once daily starting on Cycle day 8 and continuing until follicle rupture or the onset of next menses if follicle rupture did not occur [pre-luteinizing hormone (LH) surge dosing] or (b) once daily beginning with the LH surge and continuing for 6 days (post-LH surge dosing). Subjects were randomly assigned to one of the above treatment schemes and received the other in the subsequent treatment Cycle. The main outcomes were evidence of ovulatory and luteal dysfunction as determined by inhibited/delayed follicle rupture and reduced luteal progesterone synthesis or lifespan, respectively. Results: A total of 20 women enrolled and completed the study (Group 1=10, Group 2=10), with similar demographics between groups. Nineteen subjects exhibited normal ovulation in the Control Cycle (one had a blunted LH peak). In comparison to Control Cycles, treatment Cycles resulted in a significant increase in ovulatory dysfunction [pre-LH treatment: 30% (6/20), p=.04; post-LH treatment: 25% (5/20), p=.04]. Mean peak progesterone, estradiol, and LH levels and luteal phase length did not differ significantly between Control and either treatment Cycle. Conclusions: Although treatment with celecoxib before or after the LH surge increases the rate of ovulatory dysfunction, most women ovulate normally. Thus, this selective COX2 inhibitor appears to be of limited usefulness as a potential emergency contraceptive.
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a nonhormonal model for emergency contraception prostaglandin synthesis inhibitor effects on luteal function and lifespan a pilot study
Contraception, 2010Co-Authors: Alison Edelman, Jeffrey T Jensen, Jon D HenneboldAbstract:Abstract Objectives The purpose of this study is to determine if the use of a specific prostaglandin endoperoxide-2 inhibitor will prevent luteal development in women. Study Design Ovulatory reproductive-aged women not using or needing hormonal contraception were prospectively followed for three menstrual Cycles. Women were randomized into two groups using a crossover design [Group 1: Control Cycle, placebo Cycle, active drug (celecoxib 400 mg orally) Cycle; Group 2: Control Cycle, celecoxib Cycle, placebo Cycle]. Study drug was dosed daily until the onset of the next menses. Demographics, menstrual Cycle length and twice-weekly progesterone (P) levels during the placebo and active drug Cycles were recorded. End points included the change in luteal phase P levels and menstrual Cycle length (days) during active drug exposure. Results A total of 11 women completed the study (Group 1, n=7; Group 2, n=4). No demographic differences were found between groups [age, race, body mass index (BMI), Control Cycle length]. A comparison of the Control and active drug Cycles for all participants demonstrated a trend toward a longer menstrual Cycle with active drug exposure [Control, 27.2 days (SD, 2.4); study drug, 28.5 days (SD, 2.5), p=.09]. Five women had a delay in the rise of their luteal phase P levels, two women had lower peak P levels and two women had no elevation of luteal phase P levels during active drug Cycle as compared to placebo Cycle. Conclusion Daily administration of a prostaglandin synthesis inhibitor may delay the timing of luteal events and, therefore, fertility in women. PTGS2 inhibitors may hold potential as an emergency contraceptive.
Mats Hamberg - One of the best experts on this subject based on the ideXlab platform.
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the effect of antiprogestin ru 486 and prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin f2 alpha concentrations
Human Reproduction, 1994Co-Authors: Kristina Gemzelldanielsson, Mats HambergAbstract:The effects of the antiprogestin RU-486 and the prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin F2 alpha (PGF2alpha) concentrations were investigated in a comparative study involving 15 healthy women. Nine women received 200 mg of orally administered RU-486 two days after the luteinizing hormone (LH) surge; six received 500 mg of naproxen five times at 12-hour intervals starting four days after the LH surge. Uterine fluid was collected through direct aspiration on Cycle days 10 LH+1 and LH+6 to LH+8 in both a Control and treatment Cycle. Uterine fluid volume was largest at ovulation. In the Control Cycles PGF2alpha concentrations decreased significantly immediately after ovulation and increased significantly on days LH+6 to LH+8 compared to concentrations on day 10. RU-486 treatment resulted in a 78% decrease in PGF2alpha compared to the amount recorded in the Control Cycle at days LH+6 to LH+8. In the naproxen treatment group PGF2alpha values decreased by about 75% in comparison to concentrations at day 10 in the treatment Cycle and days LH+6 to LH+8 in the Control Cycle. Prostaglandins produced by the endometrium or blastocyst are considered crucial to the implantation process. These findings suggest that postovulatory administration of RU-486 prevents implantation presumably through inhibition of the secretory development of the endometrium. RU-486-induced inhibition of PGF2alpha release through the uterine fluid also may be a relevant factor.
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endocrinology the effect of antiprogestin ru 486 and prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin f2α concentrations
Human Reproduction, 1994Co-Authors: Kristina Gemzelldanielsson, Mats HambergAbstract:The effects of the antiprogestin RU-486 and the prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin F2 alpha (PGF2alpha) concentrations were investigated in a comparative study involving 15 healthy women. Nine women received 200 mg of orally administered RU-486 two days after the luteinizing hormone (LH) surge; six received 500 mg of naproxen five times at 12-hour intervals starting four days after the LH surge. Uterine fluid was collected through direct aspiration on Cycle days 10 LH+1 and LH+6 to LH+8 in both a Control and treatment Cycle. Uterine fluid volume was largest at ovulation. In the Control Cycles PGF2alpha concentrations decreased significantly immediately after ovulation and increased significantly on days LH+6 to LH+8 compared to concentrations on day 10. RU-486 treatment resulted in a 78% decrease in PGF2alpha compared to the amount recorded in the Control Cycle at days LH+6 to LH+8. In the naproxen treatment group PGF2alpha values decreased by about 75% in comparison to concentrations at day 10 in the treatment Cycle and days LH+6 to LH+8 in the Control Cycle. Prostaglandins produced by the endometrium or blastocyst are considered crucial to the implantation process. These findings suggest that postovulatory administration of RU-486 prevents implantation presumably through inhibition of the secretory development of the endometrium. RU-486-induced inhibition of PGF2alpha release through the uterine fluid also may be a relevant factor.
Changliang Xia - One of the best experts on this subject based on the ideXlab platform.
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a torque Control strategy for torque ripple reduction of brushless dc motor with nonideal back electromotive force
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Tingna Shi, Yanfei Cao, Guokai Jiang, Xinmin Li, Changliang XiaAbstract:This paper proposes a new torque Control strategy to reduce torque ripple of brushless dc motor. All possible combinations of terminal voltages are obtained from different switching states of the inverter during normal conduction period and commutation period. Moreover, the expressions of torque variation rates, corresponding to different terminal voltages, are derived to analyze the sign and the magnitude of the torque variation rates. Based on this analysis, two switching tables with main vector (MV) and subsidiary vector (SV) in these two periods are established, respectively. Through the combined effect of MV and SV in each Control Cycle, the torque ripple caused by both nonideal back electromotive force and current commutation can be reduced effectively. Meanwhile, dynamic performance of torque and switching times are taken into account. Especially in the commutation period, a unified vector selection table is applied over the entire speed range without distinguishing high speed and low speed. Finally, the effectiveness of the proposed strategy is verified by experimental results.
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a torque Control strategy for torque ripple reduction of brushless dc motor with nonideal back electromotive force
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Tingna Shi, Yanfei Cao, Guokai Jiang, Changliang XiaAbstract:This paper proposes a new torque Control strategy to reduce torque ripple of brushless dc motor. All possible combinations of terminal voltages are obtained from different switching states of the inverter during normal conduction period and commutation period. Moreover, the expressions of torque variation rates, corresponding to different terminal voltages, are derived to analyze the sign and the magnitude of the torque variation rates. Based on this analysis, two switching tables with main vector (MV) and subsidiary vector (SV) in these two periods are established, respectively. Through the combined effect of MV and SV in each Control Cycle, the torque ripple caused by both nonideal back electromotive force and current commutation can be reduced effectively. Meanwhile, dynamic performance of torque and switching times are taken into account. Especially in the commutation period, a unified vector selection table is applied over the entire speed range without distinguishing high speed and low speed. Finally, the effectiveness of the proposed strategy is verified by experimental results.
Kristina Gemzelldanielsson - One of the best experts on this subject based on the ideXlab platform.
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the effect of antiprogestin ru 486 and prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin f2 alpha concentrations
Human Reproduction, 1994Co-Authors: Kristina Gemzelldanielsson, Mats HambergAbstract:The effects of the antiprogestin RU-486 and the prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin F2 alpha (PGF2alpha) concentrations were investigated in a comparative study involving 15 healthy women. Nine women received 200 mg of orally administered RU-486 two days after the luteinizing hormone (LH) surge; six received 500 mg of naproxen five times at 12-hour intervals starting four days after the LH surge. Uterine fluid was collected through direct aspiration on Cycle days 10 LH+1 and LH+6 to LH+8 in both a Control and treatment Cycle. Uterine fluid volume was largest at ovulation. In the Control Cycles PGF2alpha concentrations decreased significantly immediately after ovulation and increased significantly on days LH+6 to LH+8 compared to concentrations on day 10. RU-486 treatment resulted in a 78% decrease in PGF2alpha compared to the amount recorded in the Control Cycle at days LH+6 to LH+8. In the naproxen treatment group PGF2alpha values decreased by about 75% in comparison to concentrations at day 10 in the treatment Cycle and days LH+6 to LH+8 in the Control Cycle. Prostaglandins produced by the endometrium or blastocyst are considered crucial to the implantation process. These findings suggest that postovulatory administration of RU-486 prevents implantation presumably through inhibition of the secretory development of the endometrium. RU-486-induced inhibition of PGF2alpha release through the uterine fluid also may be a relevant factor.
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endocrinology the effect of antiprogestin ru 486 and prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin f2α concentrations
Human Reproduction, 1994Co-Authors: Kristina Gemzelldanielsson, Mats HambergAbstract:The effects of the antiprogestin RU-486 and the prostaglandin biosynthesis inhibitor naproxen on uterine fluid prostaglandin F2 alpha (PGF2alpha) concentrations were investigated in a comparative study involving 15 healthy women. Nine women received 200 mg of orally administered RU-486 two days after the luteinizing hormone (LH) surge; six received 500 mg of naproxen five times at 12-hour intervals starting four days after the LH surge. Uterine fluid was collected through direct aspiration on Cycle days 10 LH+1 and LH+6 to LH+8 in both a Control and treatment Cycle. Uterine fluid volume was largest at ovulation. In the Control Cycles PGF2alpha concentrations decreased significantly immediately after ovulation and increased significantly on days LH+6 to LH+8 compared to concentrations on day 10. RU-486 treatment resulted in a 78% decrease in PGF2alpha compared to the amount recorded in the Control Cycle at days LH+6 to LH+8. In the naproxen treatment group PGF2alpha values decreased by about 75% in comparison to concentrations at day 10 in the treatment Cycle and days LH+6 to LH+8 in the Control Cycle. Prostaglandins produced by the endometrium or blastocyst are considered crucial to the implantation process. These findings suggest that postovulatory administration of RU-486 prevents implantation presumably through inhibition of the secretory development of the endometrium. RU-486-induced inhibition of PGF2alpha release through the uterine fluid also may be a relevant factor.
Tingna Shi - One of the best experts on this subject based on the ideXlab platform.
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a torque Control strategy for torque ripple reduction of brushless dc motor with nonideal back electromotive force
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Tingna Shi, Yanfei Cao, Guokai Jiang, Xinmin Li, Changliang XiaAbstract:This paper proposes a new torque Control strategy to reduce torque ripple of brushless dc motor. All possible combinations of terminal voltages are obtained from different switching states of the inverter during normal conduction period and commutation period. Moreover, the expressions of torque variation rates, corresponding to different terminal voltages, are derived to analyze the sign and the magnitude of the torque variation rates. Based on this analysis, two switching tables with main vector (MV) and subsidiary vector (SV) in these two periods are established, respectively. Through the combined effect of MV and SV in each Control Cycle, the torque ripple caused by both nonideal back electromotive force and current commutation can be reduced effectively. Meanwhile, dynamic performance of torque and switching times are taken into account. Especially in the commutation period, a unified vector selection table is applied over the entire speed range without distinguishing high speed and low speed. Finally, the effectiveness of the proposed strategy is verified by experimental results.
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a torque Control strategy for torque ripple reduction of brushless dc motor with nonideal back electromotive force
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Tingna Shi, Yanfei Cao, Guokai Jiang, Changliang XiaAbstract:This paper proposes a new torque Control strategy to reduce torque ripple of brushless dc motor. All possible combinations of terminal voltages are obtained from different switching states of the inverter during normal conduction period and commutation period. Moreover, the expressions of torque variation rates, corresponding to different terminal voltages, are derived to analyze the sign and the magnitude of the torque variation rates. Based on this analysis, two switching tables with main vector (MV) and subsidiary vector (SV) in these two periods are established, respectively. Through the combined effect of MV and SV in each Control Cycle, the torque ripple caused by both nonideal back electromotive force and current commutation can be reduced effectively. Meanwhile, dynamic performance of torque and switching times are taken into account. Especially in the commutation period, a unified vector selection table is applied over the entire speed range without distinguishing high speed and low speed. Finally, the effectiveness of the proposed strategy is verified by experimental results.