Leo Vankrieken - Academia.edu (original) (raw)
Papers by Leo Vankrieken
The Journal of Clinical Endocrinology & Metabolism, 1991
In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a se... more In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a sensitive ovine pituitary cell culture system. Human inhibin activities were detected in a range between 0.02-5.28 U/mL at six dilutions by using serum from the 38-week pregnant women as a quality control. A remarkable increase in serum inhibin was observed from 4 to 38 weeks of pregnancy. The mean serum inhibin level was 1.58 U/mL at 4 weeks. Thereafter, inhibin levels increased progressively with the weeks of pregnancy (r = 0.988; P less than 0.001). In the midterm of pregnancy, serum inhibin was elevated at average levels of 2.84 and 3.84 U/mL at 20 and 28 weeks, respectively. The peak level of inhibin (5.33 U/mL) was obtained at 38 weeks, which was an increase of 237% compared to that at 4 weeks. The average rate of increase in serum inhibin levels was 14.51% every 2-4 weeks (ranging from 8.1-20%). These findings suggest that circulating inhibin is useful marker during human pregnancy.
Los Angeles: Diagnostic Products …, 1997
Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and ... more Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and hirsutism and virilism in females.
The following pages show estradiol results for nine subjects (designated “A ” through “I”) follow... more The following pages show estradiol results for nine subjects (designated “A ” through “I”) followed on a daily basis throughout an ovulatory cycle, against the backdrop of reference range results generated in Diagnostic Products Corporation’s Multicenter Ovulatory Cycle Study. For each sample, three estradiol results were available for comparison: 1. IMMULITE ® Estradiol (LKE2), 2. IMMULITE ® 2000 Estradiol (L2KE2), and 3. Coat-A-Count ® Estradiol-6 (TKSE) — an antibodycoated tube radioimmunoassay. The graphs serve to demonstrate in clinical context the extent of agreement among the three methods.
Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and ... more Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and hirsutism and virilism in females.
Fertility and Sterility, 1989
The contribution of the ovary to the circulating total renin pool is linked to its secretory acti... more The contribution of the ovary to the circulating total renin pool is linked to its secretory activity in relation with its reproductive function. In a longitudinal study of 13 normal women, total renin levels measured in serum by an immunoradiometric assay were lower in the midfollicular phase (180 +/- 59 pg/ml) than in the midluteal phase (291 +/- 100 pg/ml). Peak levels were encountered 1 day after the luteinizing hormone (LH) surge (375 +/- 97 pg/ml). Rapid circhoral fluctuations were observed in all periods of the cycle, unrelated to the LH pulses. In case of ovarian function inhibition (induced by gonadotropin-releasing hormone agonists), total renin levels were lower than in the midfollicular phase (126 +/- 56 pg/ml). Low levels also were encountered in the prepubertal period (153 +/- 89 pg/ml). Very high levels (17,600 +/- 11,400 pg/ml) were found in follicular fluids from stimulated cycles. These results show that circulating total renin levels follow a complex pattern in which LH, but possibly also follicle-stimulating hormone and gonadal steroid hormones (estradiol and progesterone), may play a role.
Journal of Clinical Endocrinology & Metabolism, 1991
In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a se... more In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a sensitive ovine pituitary cell culture system. Human inhibin activities were detected in a range between 0.02-5.28 U/mL at six dilutions by using serum from the 38-week pregnant women as a quality control. A remarkable increase in serum inhibin was observed from 4 to 38 weeks of pregnancy. The mean serum inhibin level was 1.58 U/mL at 4 weeks. Thereafter, inhibin levels increased progressively with the weeks of pregnancy (r = 0.988; P less than 0.001). In the midterm of pregnancy, serum inhibin was elevated at average levels of 2.84 and 3.84 U/mL at 20 and 28 weeks, respectively. The peak level of inhibin (5.33 U/mL) was obtained at 38 weeks, which was an increase of 237% compared to that at 4 weeks. The average rate of increase in serum inhibin levels was 14.51% every 2-4 weeks (ranging from 8.1-20%). These findings suggest that circulating inhibin is useful marker during human pregnancy.
Fertility and sterility, 1989
Several regimens have been developed to administer gonadotropin-releasing hormone agonists in ass... more Several regimens have been developed to administer gonadotropin-releasing hormone agonists in association with human menopausal gonadotropins (hMG) during follicular growth stimulation for in vitro fertilization. The aim of this study was to characterize hormonal changes induced by short-term administration of agonist, and to evaluate a putative impact of the flare-up effect on follicular recruitment and subsequent IVF. Eighteen highly selected patients were randomely divided in two groups. Nine patients received a short-term administration of Buserelin (Hoechst, AG, Franfurt/Main, FRG) (day 1). They were compared with 9 patients who were exposed to a long-term protocol (day 21), and 13 control patients. Agonist-induced luteinizing hormone (LH) and follicle-stimulating hormone (FSH) increase, in early follicular phase, stimulated follicular growth, shortened follicular phase, and induced a transient rise in progesterone. This was followed by a phase of reduced LH secretion associate...
American journal of obstetrics and gynecology, 1990
Ovulation inhibition by the monophasic oral contraceptive containing 75 ug of gestodene and 30 ug... more Ovulation inhibition by the monophasic oral contraceptive containing 75 ug of gestodene and 30 ug of ethinyl estradiol was evaluated in 25 healthy volunteers for five cycles: a pretreatment cycle, three treatment cycles, and a posttreatment cycle. Serum luteinizing and follicle- stimulating hormones, estradiol, and progesterone levels were measured on days 8 through 17; progesterone was measured once, around day 21. Pelvic ultrasound examinations were performed on cycle days 8 to 17, luteinizing and follicle-stimulating hormone levels reached values on the lower limit of detection. Luteal activity was not detected in treated cycles. Follicular activity, which was reflected by estradiol levels, was mot strongly depressed during the first treated cycle. Pelvic ultrasound examinations confirmed excellent inhibition of follicular maturation. Restoration of ovarian function in the posttreatment cycle was excellent and showed a midcycle hormonal profile identical to the pretrial cycle.
Ann Clin Biochem, 2005
tion of the extra Cu. If this patient had an issue relating to protein metabolism, then this woul... more tion of the extra Cu. If this patient had an issue relating to protein metabolism, then this would not have been the case and both plasma Cu and caeruloplasmin concentrations would have remained low. Case 2 did not show the same rise in plasma Cu and caeruloplasmin as Case 1, and only showed a small responsewhen extra copper supplementationwas given at a time di¡erent from other medication. The carer for this patient was concerned about the increased bowel movements associated with the administration of the Minedex solution, which contains iron and manganese in addition to copper. We suspect that the extra supplemental Cu was not being administered with the same regularity in Case 2 as in Case1. There are certainly no reasons to suspect any issues relating to protein synthesis in Case 2. This latter patient was on enteral feeding following a CVAand had no previous medical history of note, with normal renal and liver function tests and a normal plasma albumin. Case 1, on the other hand, was a very frail elderly lady with a history of liver disease, who has recently died.We do intend to follow up Case 2 by carrying out an isotopic Cu absorption test. I agree with Twomey et al. that low plasma Cu concentrations per se are not necessarily due to copper de¢ciency. However, patients with low plasma Cu due to copper de¢ciency also have associated low plasma concentrations of caeruloplasmin.
Taiwanese journal of obstetrics & gynecology, 2009
To determine the acceptability and effectiveness of a gonadotropin-releasing hormone (GnRH) agoni... more To determine the acceptability and effectiveness of a gonadotropin-releasing hormone (GnRH) agonist for the treatment of perimenopausal women with symptomatic uterine myomas. The participants included 43 women with symptomatic myomas who wished to retain their uteri. All the women were older than 45 years old, agreed to use the GnRH agonist for menopause induction, and were without any underlying malignancy. They were treated with six courses of GnRH agonist between 2004 and 2005. The definition of re-intervention included: (1) surgical intervention, such as hysterectomy, myomectomy or laparoscopic uterine vessel occlusion, or (2) modification of GnRH agonist use. Modification of GnRH agonist use included either failure to complete a 6-month GnRH agonist treatment course, or re-use of GnRH agonist with/without interruption of continuity. Failure was defined as women who underwent surgical intervention or failed to complete the 6-month GnRH agonist treatment. Evaluations were perform...
Annals of Clinical Biochemistry, 2005
The Journal of Clinical Endocrinology & Metabolism, 1991
In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a se... more In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a sensitive ovine pituitary cell culture system. Human inhibin activities were detected in a range between 0.02-5.28 U/mL at six dilutions by using serum from the 38-week pregnant women as a quality control. A remarkable increase in serum inhibin was observed from 4 to 38 weeks of pregnancy. The mean serum inhibin level was 1.58 U/mL at 4 weeks. Thereafter, inhibin levels increased progressively with the weeks of pregnancy (r = 0.988; P less than 0.001). In the midterm of pregnancy, serum inhibin was elevated at average levels of 2.84 and 3.84 U/mL at 20 and 28 weeks, respectively. The peak level of inhibin (5.33 U/mL) was obtained at 38 weeks, which was an increase of 237% compared to that at 4 weeks. The average rate of increase in serum inhibin levels was 14.51% every 2-4 weeks (ranging from 8.1-20%). These findings suggest that circulating inhibin is useful marker during human pregnancy.
Los Angeles: Diagnostic Products …, 1997
Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and ... more Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and hirsutism and virilism in females.
The following pages show estradiol results for nine subjects (designated “A ” through “I”) follow... more The following pages show estradiol results for nine subjects (designated “A ” through “I”) followed on a daily basis throughout an ovulatory cycle, against the backdrop of reference range results generated in Diagnostic Products Corporation’s Multicenter Ovulatory Cycle Study. For each sample, three estradiol results were available for comparison: 1. IMMULITE ® Estradiol (LKE2), 2. IMMULITE ® 2000 Estradiol (L2KE2), and 3. Coat-A-Count ® Estradiol-6 (TKSE) — an antibodycoated tube radioimmunoassay. The graphs serve to demonstrate in clinical context the extent of agreement among the three methods.
Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and ... more Testosterone measurements are very helpful in the evaluation of hypogonadal states in males, and hirsutism and virilism in females.
Fertility and Sterility, 1989
The contribution of the ovary to the circulating total renin pool is linked to its secretory acti... more The contribution of the ovary to the circulating total renin pool is linked to its secretory activity in relation with its reproductive function. In a longitudinal study of 13 normal women, total renin levels measured in serum by an immunoradiometric assay were lower in the midfollicular phase (180 +/- 59 pg/ml) than in the midluteal phase (291 +/- 100 pg/ml). Peak levels were encountered 1 day after the luteinizing hormone (LH) surge (375 +/- 97 pg/ml). Rapid circhoral fluctuations were observed in all periods of the cycle, unrelated to the LH pulses. In case of ovarian function inhibition (induced by gonadotropin-releasing hormone agonists), total renin levels were lower than in the midfollicular phase (126 +/- 56 pg/ml). Low levels also were encountered in the prepubertal period (153 +/- 89 pg/ml). Very high levels (17,600 +/- 11,400 pg/ml) were found in follicular fluids from stimulated cycles. These results show that circulating total renin levels follow a complex pattern in which LH, but possibly also follicle-stimulating hormone and gonadal steroid hormones (estradiol and progesterone), may play a role.
Journal of Clinical Endocrinology & Metabolism, 1991
In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a se... more In this study bioactive inhibin was measured in 112 serum samples from 103 pregnant women by a sensitive ovine pituitary cell culture system. Human inhibin activities were detected in a range between 0.02-5.28 U/mL at six dilutions by using serum from the 38-week pregnant women as a quality control. A remarkable increase in serum inhibin was observed from 4 to 38 weeks of pregnancy. The mean serum inhibin level was 1.58 U/mL at 4 weeks. Thereafter, inhibin levels increased progressively with the weeks of pregnancy (r = 0.988; P less than 0.001). In the midterm of pregnancy, serum inhibin was elevated at average levels of 2.84 and 3.84 U/mL at 20 and 28 weeks, respectively. The peak level of inhibin (5.33 U/mL) was obtained at 38 weeks, which was an increase of 237% compared to that at 4 weeks. The average rate of increase in serum inhibin levels was 14.51% every 2-4 weeks (ranging from 8.1-20%). These findings suggest that circulating inhibin is useful marker during human pregnancy.
Fertility and sterility, 1989
Several regimens have been developed to administer gonadotropin-releasing hormone agonists in ass... more Several regimens have been developed to administer gonadotropin-releasing hormone agonists in association with human menopausal gonadotropins (hMG) during follicular growth stimulation for in vitro fertilization. The aim of this study was to characterize hormonal changes induced by short-term administration of agonist, and to evaluate a putative impact of the flare-up effect on follicular recruitment and subsequent IVF. Eighteen highly selected patients were randomely divided in two groups. Nine patients received a short-term administration of Buserelin (Hoechst, AG, Franfurt/Main, FRG) (day 1). They were compared with 9 patients who were exposed to a long-term protocol (day 21), and 13 control patients. Agonist-induced luteinizing hormone (LH) and follicle-stimulating hormone (FSH) increase, in early follicular phase, stimulated follicular growth, shortened follicular phase, and induced a transient rise in progesterone. This was followed by a phase of reduced LH secretion associate...
American journal of obstetrics and gynecology, 1990
Ovulation inhibition by the monophasic oral contraceptive containing 75 ug of gestodene and 30 ug... more Ovulation inhibition by the monophasic oral contraceptive containing 75 ug of gestodene and 30 ug of ethinyl estradiol was evaluated in 25 healthy volunteers for five cycles: a pretreatment cycle, three treatment cycles, and a posttreatment cycle. Serum luteinizing and follicle- stimulating hormones, estradiol, and progesterone levels were measured on days 8 through 17; progesterone was measured once, around day 21. Pelvic ultrasound examinations were performed on cycle days 8 to 17, luteinizing and follicle-stimulating hormone levels reached values on the lower limit of detection. Luteal activity was not detected in treated cycles. Follicular activity, which was reflected by estradiol levels, was mot strongly depressed during the first treated cycle. Pelvic ultrasound examinations confirmed excellent inhibition of follicular maturation. Restoration of ovarian function in the posttreatment cycle was excellent and showed a midcycle hormonal profile identical to the pretrial cycle.
Ann Clin Biochem, 2005
tion of the extra Cu. If this patient had an issue relating to protein metabolism, then this woul... more tion of the extra Cu. If this patient had an issue relating to protein metabolism, then this would not have been the case and both plasma Cu and caeruloplasmin concentrations would have remained low. Case 2 did not show the same rise in plasma Cu and caeruloplasmin as Case 1, and only showed a small responsewhen extra copper supplementationwas given at a time di¡erent from other medication. The carer for this patient was concerned about the increased bowel movements associated with the administration of the Minedex solution, which contains iron and manganese in addition to copper. We suspect that the extra supplemental Cu was not being administered with the same regularity in Case 2 as in Case1. There are certainly no reasons to suspect any issues relating to protein synthesis in Case 2. This latter patient was on enteral feeding following a CVAand had no previous medical history of note, with normal renal and liver function tests and a normal plasma albumin. Case 1, on the other hand, was a very frail elderly lady with a history of liver disease, who has recently died.We do intend to follow up Case 2 by carrying out an isotopic Cu absorption test. I agree with Twomey et al. that low plasma Cu concentrations per se are not necessarily due to copper de¢ciency. However, patients with low plasma Cu due to copper de¢ciency also have associated low plasma concentrations of caeruloplasmin.
Taiwanese journal of obstetrics & gynecology, 2009
To determine the acceptability and effectiveness of a gonadotropin-releasing hormone (GnRH) agoni... more To determine the acceptability and effectiveness of a gonadotropin-releasing hormone (GnRH) agonist for the treatment of perimenopausal women with symptomatic uterine myomas. The participants included 43 women with symptomatic myomas who wished to retain their uteri. All the women were older than 45 years old, agreed to use the GnRH agonist for menopause induction, and were without any underlying malignancy. They were treated with six courses of GnRH agonist between 2004 and 2005. The definition of re-intervention included: (1) surgical intervention, such as hysterectomy, myomectomy or laparoscopic uterine vessel occlusion, or (2) modification of GnRH agonist use. Modification of GnRH agonist use included either failure to complete a 6-month GnRH agonist treatment course, or re-use of GnRH agonist with/without interruption of continuity. Failure was defined as women who underwent surgical intervention or failed to complete the 6-month GnRH agonist treatment. Evaluations were perform...
Annals of Clinical Biochemistry, 2005