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Biomedical subjects

P A van Dop

Publications and source records attributed to P A van Dop.

17 recordsLinked to original sources
PubMed2006

A randomized clinical trial of clomiphene citrate versus low dose recombinant FSH for ovarian hyperstimulation in intrauterine insemination cycles for unexplained and male subfertility.

BACKGROUND: Controlled ovarian hyperstimulation with intrauterine insemination (IUI) is a widely accepted treatment for unexplained and male subfertility. No consensus exists about the drug of first choice to be used as hyperstimulation. This randomized multicentre trial using a parallel design compares the efficacy of clomiphene citrate (CC) with that of recombinant FSH (rFSH). METHODS: Couples with primary unexplained or male subfertility were randomized to receive CC or rFSH for ovarian hyperstimulation. The treatment was continued for up to four cycles unless pregnancy occurred. Cycles with more than three follicles were cancelled. Cumulative pregnancy rates and live birth rates were primary outcomes. Cancellation during treatment and multiple birth rates are secondary outcomes. Results were analysed following the intention-to-treat principle. RESULTS: Seventy couples with male subfertility and 68 couples with unexplained subfertility were included. Seventy-one women received CC, and 67 received rFSH. Twenty-seven pregnancies were observed in the CC group (38%) and 23 in the rFSH group (34.3%) relative risk (RR) 1.11 [95% confidence interval (95% CI) 0.71-1.73]. The live birth rate was 28.2% (20/71) and 26.9% (18/67) for CC and rFSH, respectively, RR 1.05 (95% CI 0.61-1.80). Overall, the live birth rates per cycle were 10% for CC-stimulated and 8.7% for rFSH stimulated cycles. The total multiple pregnancy rate was 6.0%. Thirty-five cycles (8.6%) were cancelled because of four or more follicles (CC, n = 17; rFSH, n = 18). CONCLUSIONS: In couples with primary unexplained or male subfertility participating in an IUI program, ovarian hyperstimulation can be achieved by CC or rFSH. No significant difference in live birth rates between CC and rFSH was observed. Being less expensive, CC seems the more cost-effective drug and therefore, can be offered as drug of first choice.

Adult↗
PubMed2002

[Results of in vitro fertilization in the Netherlands, 1996-2000].

OBJECTIVE: To describe the annual results in all 13 Dutch in vitro fertilisation (IVF) centres in the period 1996-2000, and to look for possible differences between individual centres and years. DESIGN: Retrospective data collection, description and analysis. METHOD: The results collected on the website of the Dutch Society of Obstetrics and Gynaecology (Dutch acronym: NVOG; www.nvog.nl) in the period 1996-2000 were integrated and described, with special attention to possible differences between centres and years. RESULTS: In 1996-2000 (5 years), 63,414 IVF or ICSI treatment cycles were started in the Netherlands, and 5,884 transfers of cryopreserved embryos were performed. The number of treatment cycles increased over the years, particularly the number of ICSI cycles. The total number of ongoing pregnancies was 12,991 (20.5% per started cycle; 22.5% for ICSI and 18.3% for IVF). Particularly during the first 3 years, there was an increase in these percentages (IVF: from 16.4% (1996) to 19.2% (1998); ICSI: from 18.3% (1996) to 23.9% (1998)). There were differences between the centres in both the percentage of ongoing pregnancies per started IVF/ICSI cycle (range 13.7-25.1%) and the percentage ICSI (14-61%) and cryo-transfers per total number of treatment cycles (0-26%). It was estimated that, during this 5-year period, 1 out of every 61 Dutch neonates resulted from IVF or ICSI. CONCLUSION: The pregnancy-rates after IVF and ICSI increased during the study period, and were comparable with the rates in other European countries. Some important data are still missing from the inventory, for example regarding the number of embryos per transfer, multiple pregnancies, live births, congenital malformations and complications.

Embryo Transfer↗
PubMed2001

Dynamics of immunoreactive endothelin plasma levels during ovarian stimulation for in vitro fertilization with and without dietary sodium restriction.

OBJECTIVE: To investigate the correlation between immunoreactive endothelin plasma levels and both the number and size of follicles and its relationship with the development of ovarian hyperstimulation syndrome, in in vitro fertilization cycles, with and without dietary sodium restriction. STUDY DESIGN: Randomized study in an assisted reproduction unit of a large teaching hospital. Data of 88 women form the basis of this report (45 ad libitum sodium intake and 43 dietary sodium restriction). Non-parametric tests were used for statistical analysis. RESULTS: Immunoreactive endothelin plasma levels neither correlate with the number of follicles, independent of their size, nor with the grade of ovarian hyperstimulation syndrome. Immunoreactive endothelin plasma levels decrease significantly in the luteal phase. These results are the same in both sodium diet groups. CONCLUSIONS: Immunoreactive endothelin plasma levels do not correlate with the number and size of follicles and they are not related to the development of ovarian hyperstimulation syndrome. These findings are independent of sodium intake.

Diet, Sodium-Restricted↗
PubMed2000

A randomized controlled study comparing the endocrine effects of pulsatile intravenous gonadotropin-releasing hormone after gonadotropin-releasing hormone agonist pretreatment versus clomiphene citrate in patients with polycystic ovary syndrome.

OBJECTIVE: To compare the endocrine changes in the follicular phase in infertile patients with polycystic ovary syndrome (PCOS) treated with either pulsatile IV GnRH after GnRH-agonist (GnRH-a) down-regulation or clomiphene citrate (CC). DESIGN: Subgroup analysis within a randomized, controlled, multicenter study. SETTING: Women referred to the Infertility Clinic, Catharina Hospital Eindhoven, The Netherlands. PATIENT(S): Twenty-eight infertile patients with PCOS. INTERVENTIONs): Patients were randomly assigned to pulsatile IV GnRH (10-20 microgram/90 min) after GnRH-a down-regulation or CC (50-150 mg; cycle days 3-7). Patients were monitored on alternate days with ovarian sonography and serum concentrations of E(2), LH, and FSH. Serum P and sonography confirmed ovulation. MAIN OUTCOME MEASURE(S): Serum concentrations of E(2), LH, and FSH were assessed before treatment was started and after each ovarian sonography. RESULT(S): In ovulatory cycles, no statistically significant differences were observed during the follicular phase comparing serum concentrations of E(2), LH, and FSH between the treatments. However, a significant increase in LH occurred in the GnRH group. CONCLUSION(S): No significant endocrine differences were observed between GnRH and CC treatment. However, there was a significant increase in the serum LH concentration during the follicular phase in the GnRH group. Increments of LH in the GnRH group may be due to recovery of endogenous LH secretion.

Adult↗
PubMed2000

Angiotensin sensitivity test revisited.

OBJECTIVE: To determine the validity of a single angiotensin sensitivity test as predictor of pregnancy-induced hypertension with special reference to the dietary sodium intake at the time of testing. METHODS: The angiotensin sensitivity test was successfully performed at 32 weeks' gestation in 104 women. In 90 of these women, the 24-h urinary sodium-creatinine ratio was known. Using an effective pressure dose of 10 ng/kg/min as the cutoff level, test characteristics were assessed in both the total population and after subdivision into a sodium restricted (n = 23) and an unrestricted diet group (n = 67). RESULTS: The incidence of pregnancy-induced hypertension was 13.4%. The number of positive angiotensin sensitivity tests was 7.5%. Test characteristics showed poor sensitivity (22.2%) and high specificity (94.8%); positive and negative predictive values were 40.0% and 88.7%, respectively. None of the sodium-restricted women was angiotensin sensitive. Sodium restriction did not have a significant influence on sensitivity, specificity, and predictive values of the test. CONCLUSION: The angiotensin sensitivity test is not an appropriate screening test to predict hypertensive disorders of pregnancy. No significant effect of dietary sodium restriction was found.

Adult↗
PubMed1998

External validation of prognostic models for ongoing pregnancy after in-vitro fertilization.

This study aimed to validate prognostic models for predicting ongoing pregnancy after the first and second in-vitro fertilization cycles. Models were developed using data from the University Hospital, Nijmegen, 1991-1994 and tested using more recent data from the same centre and data from two other centres. Although the variables included in the models seemed plausible, the predictions of the models were unsatisfactory. The models did not discriminate between women who had achieved pregnancy and women who did not achieve pregnancy; neither could they indicate which women had a (very) low probability of ongoing pregnancy. Taking into account the success rate of a specific clinic or the success rate during a specific period did not show any advantage. The predictions were even inaccurate in the same hospital during another period. It is obvious that these prognostic models should not be used. This study shows the importance of validating prognostic models before their implementation in clinical practice.

Adult↗
PubMed1998

Ovarian hyperstimulation syndrome: facts and fallacies.

Severe or critical ovarian hyperstimulation syndrome (OHSS) is a serious complication of ovarian hyperstimulation for assisted reproduction techniques (ART). The syndrome is characterized by cystic enlargement of the ovaries and fluid shifts from the intravascular to the third space. The morbidity in OHSS is mainly determined by the hemodynamic changes caused by increased capillary permeability. The incidence of OHSS depends on definitions, risk factors, ovarian stimulation protocols, luteal support and conception. Currently, research on the pathogenesis of OHSS is focused on increased capillary permeability. Several theories are reviewed. Until the pathogenesis of OHSS becomes clear, treatment is restricted to supportive therapy. The various proposals for management of OHSS are discussed and, based on the available data, directions for the management of various grades of OHSS are summarized. However, prevention and early recognition are still the most important tools to handle OHSS. A flowchart with preventive measures for OHSS is presented derived from the available literature.

Algorithms↗
PubMed1997

Two sibs with chorioretinal dystrophy, hypogonadotrophic hypogonadism, and cerebellar ataxia: Boucher-Neuhäuser syndrome.

We describe two sibs with chorioretinal dystrophy, hypogonadotrophic hypogonadism, and cerebellar ataxia, Boucher-Neuhäuser syndrome, a rare but distinct pleiotropic single gene disorder with an autosomal recessive pattern of inheritance. The cases presented illustrate that this syndrome is still poorly recognised. We provide a review and analysis of previously reported cases and the differential diagnosis, which might aid in the identification of additional cases.

Adult↗
PubMed1996

Prognostic models for the probability of achieving an ongoing pregnancy after in-vitro fertilization and the importance of testing their predictive value.

The aim of this study was to create reliable models to predict the probability of achieving an ongoing pregnancy during in-vitro fertilization (IVF) treatment: model A, at the start of the first treatment, model B at the time of embryo transfer, and model C, during the second treatment at the end of the first IVF treatment. Prognostic models were created using data from the University Hospital Nijmegen (n = 757) and applied to the data from the Catharina Hospital Eindhoven (n = 432), The Netherlands, to test their predictive performance. The predictions of model B (made at time of embryo transfer) were fairly good (c = 0.672 in the test population). For instance, 93% of the patients who had a predicted probability of achieving an ongoing pregnancy of < 10% did not achieve an ongoing pregnancy. However, the predictions of the other two models (A and C) for Eindhoven were less reliable. The predictive value of model C was fairly high in Nijmegen (c = 0.673). Its poor performance in the test population may be explained partly by differences in effectiveness of the ovulation stimulation protocols and the decision about when to discontinue the cycle. Thus, before using prognostic models at an IVF centre, their reliability at that specific centre should be tested.

Evaluation Studies as Topic↗
PubMed1996

The influence of dietary sodium restriction on renal and ovarian renin and prorenin production during ovarian stimulation.

In a prospective study, the effect of dietary sodium restriction on plasma and follicular fluid renin and prorenin concentrations and on fertilization measures was investigated during ovarian stimulation. In all, 18 women undergoing ovarian stimulation for in-vitro fertilization and embryo transfer were randomly divided into groups with and without sodium restriction. Plasma renin and prorenin concentrations were higher in the low sodium than in the normal sodium group. Plasma renin concentrations showed a mid-luteal rise. Plasma prorenin concentrations increased 4-fold on the day of oocyte retrieval, followed by a gradual decline to basal values. The low sodium group had more follicles than the normal sodium group. Neither follicular fluid renin and prorenin concentrations, nor the total amount of follicular fluid renin and prorenin per ovary differed significantly between the two groups. Oocyte yield and fertilization rates were similar in both groups. These rates were correlated with neither renin nor prorenin concentrations in follicular fluid. We conclude that sodium restriction did not influence cyclic plasma variation of renin or prorenin or follicular fluid renin and prorenin concentrations. In addition, fertilization rates were not affected by sodium restriction.

Blood Pressure↗
PubMed1991

Initiation of spermatogenesis and successful in vitro fertilization in an infertile male with panhypopituitarism; superiority of pulsatile LH-RH over gonadotropins? A case report.

This case report describes an infertile male patient with panhypopituitarism, presumably caused by traumatic breech delivery. Previous hMG/hCG treatment had failed to induce spermatogenesis. Initiation of the production of motile and morphological normal sperm, despite persisting significant oligozoospermia was established with s.c. pulsatile LH-RH treatment. Spermatogenesis could be maintained with i.m. hCG injections bi-weekly. Later, fruitful in vitro fertilization (IVF) resulted in the birth of a healthy daughter.

Adult↗
PubMed1985

Pulsatile luteinizing hormone patterns in the follicular phase of the menstrual cycle, polycystic ovarian disease (PCOD) and non-PCOD secondary amenorrhea.

To characterize the oscillations of plasma LH in normally cycling and amenorrheic women, three groups of women were studied: I, normal women during the follicular phase of the cycle (n = 9); II, women with polycystic ovarian disease (PCOD; n = 11); and III, women with non-PCOD secondary amenorrhea (n = 12). Blood samples were obtained at 10-min intervals for 6 h on 2 separate days. A pulse was defined as an increase in LH at least 20% over the preceding lowest value (nadir). Since LHRH release immediately follows the nadir of the LH levels, the nadir interval (NI) was used for analysis. For analysis, the results from 1 day were selected at random from each subject, and from each day, the same number of NIs also were randomly selected. When two NIs from each patient were selected, the median NI was 75 min in group I, 45 min in group II, and 45 min in group III. When three or four NIs were chosen, the median NI was 60 min in group I, 50 min in group II, and 40 min in group III. The differences between the groups were statistically significant. When three NIs were selected, the mean of the corresponding LH amplitudes was 2.8 U/liter in group I, 6.0 U/liter in group II, and 1.5 U/liter in group III. The differences between these groups were statistically significant. Thus, the NI in PCOD patients was shorter than that during the follicular phase of the cycle, but this short NI is not unique for PCOD, since the NI in non-PCOD secondary amenorrhea patients was even smaller. The LH amplitude was higher in PCOD and lower in non-PCOD secondary amenorrhea compared to that during the follicular phase of the cycle. The decrease in NI in PCOD and/or non-PCOD secondary amenorrhea vs. the NI of the follicular phase could be explained by either a higher frequency of LHRH pulses from the hypothalamus or an increased sensitivity of the pituitary leading to a greater response of the pituitary to LHRH pulses.

Adolescent↗
PubMed1980

A quantitative structural model of the testis of fertile males with normal sperm counts.

The morphology of testicular biopsies of 8 healthy fertile men with proven normal sperm counts was studied using stereological techniques. Quantitative estimations were made of different cellular compartments in the testicular biopsies. The experimental errors of observation, homogeneity of the section, accuracy of the measurements and errors caused during the preparation of the sections were studied. A stereological model of the human testis comprising all compartments was designed. The present observations on the stereological parameters were compared with the results in literature; generally a good agreement was found. This stereological model enabled the authors to establish the quantitative correlations that exist between the separate compartments of the human testis. The tubular length density was positively correlated with the tubular surface density. The tubular surface density showed a negative correlation with the volume density of the germinal cell nuclei. The tubular volume density showed a negative correlation with the volume density of the Leydig cells. The intra-tubular volume density correlated negatively with the volume density of the Leydig cells and with the volume density of the remaining extra-tubular tissue. The intra-tubular tissue density correlated negatively with the volume density of the intra-tubular space.

Biopsy↗