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Biomedical subjects

C B Lambalk

Publications and source records attributed to C B Lambalk.

At least 55 records · Page 3Linked to original sources
PubMed1999

Successful in-vitro fertilization in a natural cycle after four previously failed attempts in stimulated cycles: case report.

A case is reported of successful in-vitro fertilization (IVF) and pregnancy in a natural cycle after four previously failed attempts with stimulated cycles. The patient began treatment at the age of 36 years and underwent four stimulated IVF cycles, each time with three embryos of good quality transferred. In one attempt, three cryopreserved embryos were transferred in a natural cycle. The patient failed to conceive. At the age of 38 years, the patient was entered into a natural cycle IVF programme. The patient conceived twice in each of her first two attempts but unfortunately aborted. In her third natural cycle of IVF, again with one oocyte obtained and one embryo transferred, the patient conceived and had a full term gestation. It is concluded that IVF in a natural cycle is a viable option for infertile women with blocked Fallopian tubes who have normal ovulatory menstrual cycles.

Adult↗
PubMed1999

Variation of luteinizing hormone and androgens in oligomenorrhoea and its implications for the study of polycystic ovary syndrome.

We measured luteinizing hormone (LH) and androgen concentrations in patients at different phases of the oligomenorrhoeic cycle and compared the results with those of patients with normogonadotrophic amenorrhoea. Several blood samples separated by >/=7 days were obtained from each of 72 patients with oligomenorrhoea and 18 with normogonadotrophic amenorrhoea. The oligomenorrhoeic cycle was divided into five phases: the postmenstrual phase week 1 (day 1-7) and week 2 (day 8-14), the specific oligomenorrhoeic phase (SOP, day 15 after a menstruation to day 21 before the next menstruation), the possibly peri-ovulatory phase (days 21-11 before menstruation) and the premenstrual phase (days 10-1 before menstruation). Samples obtained in the possibly peri-ovulatory phase were excluded. Within individuals LH concentrations were significantly higher during the SOP than during all other phases of the oligomenorrhoeic cycle (paired t-test, P = 0.0001-0.03). In contrast to the other phases of the oligomenorrhoeic cycle, no significant differences in gonadotrophins, androgen or oestradiol concentrations were found between the SOP and normogonadotrophic amenorrhoea. In oligomenorrhoea timing of blood sampling influences the measurement of LH and androgen concentrations, and the accurate interpretation of these measurements requires that the dates of menstruation both before and after the sample is taken should be known. In patients with oligomenorrhoea blood samples should be obtained during the SOP, when the endocrinology is comparable with that of normogonadotrophic amenorrhoea.

Adult↗
PubMed1998

The endocrinology of dizygotic twinning in the human.

Heredity, higher maternal age and increased parity are well defined conditions associated with dizygotic twinning. An endocrine model of excessive secretion of pituitary gonadotrophic hormones explains multiple ovulation as a result of multiple follicle growth. In hereditary conditions FSH levels are indeed clearly elevated because of increase in stimulating mechanisms that regulate pituitary gonadotropin secretion while in most non-hereditary conditions, overshoot FSH secretions occurs as a result of diminished ovarian feedback. Puberty is a condition in which the hypothalamic LHRH pulse generator is reinitiated and this is typically characterized by temporary overshoot LH and FSH secretion, probably due to not yet fully operational ovarian feedback. In adult females situations can be found that mimic this peripubertal event such as while recovering from hypothalamic amenorrhea. Under these circumstances more DZ twinning can be observed. Elevated FSH levels along with ageing in premenopausal women probably underlie the age related increased risk of dizygotic twinning. The apparent paradox in the combination of age related decline in fecundity and rise in twinning risk can be explained by incidental presence in the cohort of more than one follicle, containing vital oocytes under deficient feedback mechanisms that lead to high FSH.

Aging↗
PubMed1998

[Secondary amenorrhea due to intrauterine adhesions: Asherman's syndrome].

Three women aged 35, 33 and 40 years had secondary amenorrhoea and monthly recurring abdominal pains after curettage for blood loss after a pregnancy. Hysteroscopy revealed intrauterine adhesions. The symptoms disappeared largely or completely after synechiolysis, introduction of an IUD and oestrogen treatment. Changes in the menstrual cycle, infertility or recurrent abortions starting after a puerperal or postabortum curettage should cause the physician to suspect intrauterine adhesions. For the diagnosis hysteroscopy is the method of choice and hysterography should be added for preoperative assessment and classification. Blind procedures for rupturing the adhesions should not be performed because of the risk of perforation and creating false routes.

Abdominal Pain↗
PubMed1998

Interpretation of elevated FSH in the regular menstrual cycle.

In reproductive medicine, abnormal elevation of serum follicle stimulating hormone (FSH) concentrations during the luteofollicular transition is associated with low response in infertility treatment. Increasing levels of serum FSH in the early follicular phase is a characteristic of reproductive ageing and has become very popular for the determination of diminished ovarian oocyte reserve. In the case of elevated FSH in premenopausal women, many more (patho)physiological mechanisms other than ageing may be responsible and should be considered also. FSH concentrations may vary considerably due to a number of factors. Next to intra-, inter- and between different assays variation there is hourly-, cycle day dependent-, intercycle and life time variation. Furthermore, physiological conditions such as during puberty, in hereditary dizygotic twinning, after use of oral contraceptives and during lactation also elevated FSH levels can be found. Pathological conditions associated with significant increases in FSH are after unilateral ovariectomy, during recovery from hypothalamic amenorrhea and with excessive smoking. It should be kept in mind, that with the interpretation of an abnormal high FSH value, just as with any other abnormal laboratory results, one should be aware, that there may be a variety of underlying causes other than the one where was aimed at.

Aging↗
PubMed1998

Follicle-stimulating hormone measured in unextracted urine: a reliable tool for easy assessment of ovarian capacity.

OBJECTIVE: To determine the presence of FSH in unextracted urine of perimenopausal women using a microparticle enzyme immunoassay kit on an AxSYM random access immunoassay analyzer. DESIGN: Controlled descriptive study. SETTING: A large teaching hospital and infertility clinic. PATIENT(S): Forty perimenopausal women aged 32-55 years admitted to our clinic for a gynecological operation. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Mean serum FSH level and urinary FSH in early-morning urine, in a random void urine sample, and in 24-hour urine on the same day. FSH in urine on the day of excretion and 1 and 4 weeks thereafter, stored under various conditions. FSH in urine before and after extraction. RESULT(S): The Pearson's correlation coefficient between mean serum FSH levels and urinary FSH in early morning urine was 0.904, in a random void 0.915, and in 24-hour urine 0.857. Determination of optimal storage conditions revealed that urine was best kept at 4 degrees C without any additive. The correlation between FSH in extracted and unextracted urine was 98.9%. CONCLUSION(S): In perimenopausal women, FSH can be reliably measured in unextracted urine. The correlation between urinary FSH and a random void urine sample and mean FSH from a serial serum sample is very high. Urine can be stored for 4 weeks at 4 degrees C without loss of FSH immunoreactivity.

Adult↗
PubMed1998

Apoptotic cell death in human granulosa-lutein cells: a possible indicator of in vitro fertilization outcome.

OBJECTIVE: To determine whether women who do not conceive during an IVF treatment despite normal FSH levels have a higher rate of apoptosis in their granulosa-lutein cells than women who do conceive. DESIGN: Prospective. SETTING: Large teaching hospital and fertility center. PATIENT(S): Patients with normal FSH levels undergoing an IVF treatment. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Outcome of the IVF treatment and percentage of apoptotic granulosa-lutein cells. RESULT(S): A significantly lower percentage of granulosa-lutein cells were apoptotic in patients who became pregnant compared with those who did not become pregnant. A higher basal FSH level was significantly correlated with the duration of the stimulation, and the number of follicles was significantly inversely correlated with the number of ampules of FSH used and the duration of the treatment. The number of embryos was significantly correlated with the number of oocytes, and significantly inversely correlated with the number of apoptotic granulosa-lutein cells. CONCLUSION(S): Fewer granulosa-lutein cells are apoptotic in women who have an ongoing pregnancy after IVF treatment than in women who do not conceive.

Adult↗
PubMed1998

Insulin-like growth factor (IGF)-I and IGF binding protein-3 concentrations in fluid from human stimulated follicles.

Insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) play an important role in regulating follicle growth and maturation. We have evaluated whether responsiveness to gonadotrophins during an in-vitro fertilization (IVF) treatment is related to follicular fluid IGF-I and IGFBP-3 concentrations. We also investigated if a difference is present in IGF-I and IGFBP-3 concentrations between patients treated with human menopausal gonadotrophin (HMG) and patients treated with highly purified follicle stimulating hormone (FSH). We have measured IGF-I and IGFBP-3 in follicular fluid from pre-ovulatory follicles in an IVF programme. All 70 patients were stimulated after being down-regulated with a gonadotrophin-releasing hormone (GnRH) analogue. IGF-I concentrations in follicular fluid were significantly inversely correlated with the number of ampoules FSH administered and number of days of FSH administration, and significantly correlated with the number of follicles aspirated. IGFBP-3 concentrations were not correlated with any other parameter measured nor were IGF-I and IGFBP-3 concentrations correlated. IGFBP-3 concentrations were significantly higher in patients receiving highly purified FSH compared with patients receiving HMG (P < 0.005). These results are new evidence that IGF-I concentration in follicular fluid is higher in women who respond better to follicular stimulation, i.e. women who grow many follicles, women who need a shorter duration of stimulation and women who need fewer ampoules FSH before oocyte retrieval.

Adult↗
PubMed1998

Gonadotrophin-releasing hormone agonist dose-dependency of pituitary desensitization during controlled ovarian hyperstimulation in IVF.

The aim of this study was to find the minimal effective daily s.c. dose of the gonadotrophin-releasing hormone (GnRH) agonist, triptorelin acetate, that suppresses the GnRH-induced release of luteinizing hormone (LH) at time of human chorionic gonadotrophin (HCG) injection and thereby prevents spontaneous LH surges during in-vitro fertilization (IVF) stimulation cycles. Therefore, a double-blind, prospective and randomized titration study was performed. A total of 48 IVF patients were divided into four groups of 12 patients. Each group received a different dose of triptorelin acetate, namely 5, 15, 50 or 100 microg s.c. daily. Standard ovarian stimulation was carried out using urinary follicle stimulating hormone (FSH) preparations. A 500 microg GnRH test was performed 90 min before the HCG injection in order to measure the degree of pituitary desensitization. Spontaneous LH surges were not detected in any of the groups, although three patients in the 5 microg group had ovulated at the time of ovum retrieval. The pituitary LH response to the GnRH test at time of HCG, expressed as area under the curve (AUC), appeared to be dose-dependent. Thus, a daily s.c. dose of 100 microg triptorelin acetate appears to be too high, since adequate desensitization of the pituitary (i.e. no spontaneous LH surge) can be achieved with doses as low as 15 and 50 microg.

Chorionic Gonadotropin↗
PubMed1998

Increased levels and pulsatility of follicle-stimulating hormone in mothers of hereditary dizygotic twins.

According to the endocrine model of hereditary dizygotic twinning, high FSH is responsible for multiple ovulation and pregnancy. Our study explored the underlying neuroendocrine causes. In a prospective clinical study, we compared the third day of menses parameters of episodic secretion of LH and FSH, the pituitary response to LHRH, plasma estradiol, and dimeric inhibin A and B in 16 regularly menstruating and 9 postmenopausal mothers of dizygotic twins with a family history of twinning and 14 premenopausal and 9 postmenopausal controls. Seven of 16 premenopausal mothers of twins had abnormally high FSH levels of more than 10 IU/L compared with 1/14 in controls (P = 0.024). In the premenopausal mothers of twins, mean FSH concentrations (P = 0.025) and FSH pulse frequency (P = 0.003) were significantly elevated, whereas FSH pulse amplitude and FSH response to LHRH were unaltered. For LH, neither the secretory parameters nor the response to LHRH was different. There were no differences between estradiol and inhibin A and B levels. Postmenopausal mothers of twin and controls did not differ with respect to the secretory pattern of LH and FSH. We conclude that under equal ovarian feedback conditions, premenopausal mothers of a dizygotic twin have hyper stimulation by endogenous FSH caused by neuroendocrine, hypothalamic, or pituitary mechanisms. This is the result of altered responsiveness to ovarian feedback and/or pituitary or suprapituitary, non-LHRH-like mechanisms that stimulate pulsatile FSH.

Adult↗
PubMed1998

Genetic risk factors in tumours of the testis: lessons from twin studies.

A threefold increase for testicular carcinoma has been reported in male dizygotic twins. In this comment we suggest the hypothesis that over-exposure to endogenously hypersecreted Follicle Stimulating Hormone (FSH) may underlie the pathogenesis. This is supported by several findings. 1) FSH hypersecretion in mothers of dizygotic twins is most likely an autosomal trait implicating the possibility of male offspring with the same hormone characteristic. 2) In testicular carcinoma higher levels of cyclin D2 are found. This is an FSH dependent stimulatory regulator of mitosis. 3) There is a marked similarity between geographical distribution in occurence of dizygotic twinning and testicular carcinoma. 4) Men undergoing surgery for testicular carcinoma have higher FSH concentrations and males with Down syndrome have higher FSH levels and are more at risk to develop testicular carcinoma. We suggest to study FSH secretion in males of familial dizygotic twins and furthermore the risk of developing testicular carcinoma in males with elevated FSH. These men with one testicle and/or with dysfunctioning Sertoli/Leydig cells.

Breast Neoplasms↗
PubMed1997

Hypothetical risks of twinning in the natural menstrual cycle.

Dizygotic (DZ) twinning is likely the result of multiple ovulation upon multiple ongoing follicle growth. Well known conditions with an increased incidence of DZ twinning are a hereditary trait, high maternal age and ovulation induction treatments. These conditions are clearly related to elevation of Follicle Stimulating Hormone (FSH) at the time of peri-menstrual follicle recruitment. In this contribution, we summarize certain other circumstances that may occur in normal women that could increase twinning rate based on the assumption that the elevation of FSH levels is the principal underlying mechanism in DZ twinning. It is hypothesized that recovery from prolonged hypothalamic amenorrhea in part mimics hormonal sequelae of puberty characterized by temporary overshoot of FSH levels. By deduction, such conditions are recovery from lactational amenorrhea, recovery from use of oral contraceptives and recovery of weight loss amenorrhea. According to the literature, these conditions indeed carry the risk of DZ twinning and all show temporary elevated FSH levels. However, prospective experiments will be needed to prove the relation between this type of DZ twinning and possible patterns of serum FSH that mimic puberty under these circumstances.

Amenorrhea↗
PubMed1997

Post-menopausal and chronological age have divergent effects on pituitary and hypothalamic function in episodic gonadotrophin secretion.

OBJECTIVE: Ageing is known to reduce gonadotrophin secretion in post-menopausal women. To what extent the hypothalamus and pituitary are involved in this process is not clear. The aim of this study was to compare pulse characteristics of FSH and LH in relation to chronological and post-menopausal age. Base on the gonadotrophin to GnRH, we assessed the extent to which pituitary and/or hypothalamic ageing is responsible for the observed changes. DESIGN: Blood samples were obtained from post-menopausal women every 10 minutes for 6 hours. Subsequently, 100 micrograms GnRH was administered intravenously and blood samples taken after 30, 60 and 90 minutes. PATIENTS: Twenty healthy women aged 47-72 years and between 1 and 30 years after the menopause. MEASUREMENTS: Plasma LH and FSH were measured by immunoradiometric assay. Pulses were identified by a computerized pulse detection program. End points were the mean number and amplitude of pulses, the mean LH and FSH concentrations during the 6-hour study period and the maximal LH and FSH increments following GnRH. RESULTS: Mean LH and FSH levels did not change with chronological age but the LH pulse frequency declined significantly and the response to GnRH increased. Mean LH levels declined with post-menopausal age without alteration in LH pulse frequency but with a significant decrease in pituitary LH response to GnRH. FSH levels remained unchanged. CONCLUSIONS: Post-menopausal ageing seems to have a major suppressive effect on pituitary gonadotroph function, while chronological ageing mainly affects the hypothalamic regulation of LH secretion.

Aged↗
PubMed1997

Specific gonadotrophin-releasing hormone analogue binding predominantly in human luteinized follicular aspirates and not in human pre-ovulatory follicles.

In an attempt to resolve the apparent controversy in the observed effects of gonadotrophin-releasing hormone (GnRH) analogues on the ovary, conventional binding studies were conducted with a GnRH agonist and an antagonist in various ovarian tissues to demonstrate possible GnRH receptor binding. In human luteinized granulosa cells derived from unstimulated in-vitro fertilization cycles, high affinity receptor binding was present in 17 out of 24 patients, while binding was not observed in any of the six pre-ovulatory follicles removed during abdominal surgery. Apparently contradictory observations on the direct ovarian effects of GnRH analogues may be the result of the intermittent presence of high affinity GnRH receptors. Our observations indicate that in the human, high affinity ovarian GnRH receptors are present predominantly in ovarian tissue after the luteinizing hormone surge. We also propose the possibility of regulation and activation of a human follicular GnRH receptor in the ovary as a physiological process which may be influenced pharmacologically.

Adult↗