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E R Te Velde

Publications and source records attributed to E R Te Velde.

10 recordsLinked to original sources
PubMed2006

Anti-Müllerian hormone levels in the spontaneous menstrual cycle do not show substantial fluctuation.

CONTEXT: Anti-Müllerian hormone (AMH), a quantitative marker for ovarian reserve, has been suggested to be independent of the classical endocrine fluctuations of the menstrual cycle. OBJECTIVE: The objective of the study was to determine whether AMH levels are constant throughout the menstrual cycle, compared with those of FSH, LH, and estradiol. DESIGN/PATIENTS: Frequent blood sampling was performed in 44 fertile, regularly cycling, female volunteers during one full menstrual cycle. SETTING: The study was conducted at a university hospital. MAIN OUTCOME MEASURES: AMH, FSH, LH, and estradiol measurements were allocated to one of seven cycle phases, and a multilevel analysis was performed. Consistent fluctuation patterns were tested by fitting sine patterns to the data. Finally, the frequency in which randomly selected individual samples would remain in one of five preset level categories (quintiles) for each of the variables was studied. RESULTS: A sine pattern fitted to the AMH data was not statistically significant (P = 0.40). In contrast, sine patterns for FSH, LH, and estradiol were highly significant. Comparing the seven cycle phases, no significant differences could be observed between phase-specific AMH levels (P = 0.06). Repeated selection of AMH samples for each individual showed that in 71.5% of selections, AMH values remained in the same quintile, whereas in 27.9% values fell in an adjacent quintile. CONCLUSIONS: AMH levels measured through a full menstrual cycle did not show consistent fluctuation patterns in contrast to levels of FSH, LH, and estradiol. Furthermore, random fluctuations were small, indicating that AMH can be relied on as a cycle-independent marker for ovarian reserve.

Adult↗
PubMed2004

Repeated clomiphene citrate challenge testing in the prediction of outcome in IVF: a comparison with basal markers for ovarian reserve.

BACKGROUND: The aim of this study was to investigate the predictive accuracy and clinical value of performing either a single or a repeated clomiphene citrate challenge test (CCCT) in predicting poor response in IVF, compared to that of currently used basal ovarian reserve markers. METHODS: Sixty-three patients undergoing their first IVF treatment were prospectively included. After measurement of basal markers on cycle day 3 (cd3) [FSH, inhibin B and antral follicle count (AFC)], a CCCT was performed. FSH and inhibin B levels were measured on day 10 (cd10). A second CCCT was performed after a washout period of one cycle. In all patients the tests were followed by an IVF treatment. Poor response (<4 oocytes or cancellation due to impaired (<3 follicles) or absent follicular growth) was used as primary outcome measure. RESULTS: Both the single as well as the repeated CCCT markers had a rather good discriminative potential for the prediction of poor response (area under the receiver operating characteristic curve (ROCAUC): FSH cd10=0.79, inhibin B cd10=0.79, mean FSH cd10=0.82 and mean inhibin B cd10=0.88). This compared well with the performance of the basal markers (FSH 0.82, inhibin B 0.72 and AFC 0.83). In a multivariate analysis on only the basal variables, FSH cd3 and AFC were selected (ROCAUC 0.89). Only stepwise forward analysis on the repeated CCCT variables revealed a better discriminating potential for the prediction of poor response (ROCAUC 0.92). At a specificity level of approximately 0.97, sensitivity and the positive predictive value were marginally improved in the CCCT models. CONCLUSIONS: Performing a CCCT (single or repeated) has a rather good ability to predict poor response in IVF. However, it appears that the predictive accuracy and clinical value of the CCCT is not clearly better than that of basal FSH in combination with an AFC. Therefore, the use of the CCCT as a predictor of outcome in IVF should not be advocated.

Adult↗
PubMed2004

The neutral comet assay detects double strand DNA damage in selected and unselected human spermatozoa of normospermic donors.

The occurrence of DNA breaks in human sperm is of concern to genetic safety in artificial reproduction techniques. Here, we have explored the neutral comet assay (NCA) for evaluating the frequency of spermatozoa with double strand (ds) DNA breaks in normospermic donors. The NCA results into DNA tail formation by fibre extension and by the separation of DNA fragments. Gamma-irradiated native, lysed and lysed plus RNA and protein degraded human sperm nuclei have been used to assess sensitivity and specificity of fragment formation as an indication for ds DNA breaks. At 5 and 10 Gy gamma irradiation, the sensitivity increases in the order: native, lysed, lysed plus RNA and protein degraded. At 10 Gy, a uniform response between donors was obtained. For technical and biological reasons, the NCA underestimates the true incidence of ds DNA breaks by an unknown factor. Semen samples of six healthy normospermic donors were differentiated by swim up and by Percoll density centrifugation, followed by the NCA. In native semen, percentages of sperm nuclei with ds DNA breaks ranged from 15 to 25%. Swim up and selection for high-density sperm nuclei (high Percoll fraction) reduced the frequency of sperm with ds DNA breaks by about one third, whereas an increased frequency was found in the low Percoll fraction. In conclusion, the response to gamma irradiation of DNA fragment formation indicates the NCA to demonstrate ds DNA breaks which is in keeping with theory and experimental results from somatic cells. Ds DNA breaks are a characteristic of the sperm population of normal donors. Current sperm selection procedures reduce the fractions of sperm with ds DNA breaks, yet are not effective in eliminating these cells.

Centrifugation, Density Gradient↗
PubMed2002

Quantitative transvaginal two- and three-dimensional sonography of the ovaries: reproducibility of antral follicle counts.

OBJECTIVE: To assess the intra- and interobserver reproducibilities in addition to the between-method reliability of antral follicle counts using two (2D)- and three (3D)-dimensional transvaginal sonography (TVS). METHODS: Two groups of women with regular menstrual cycles were studied. One group consisted of healthy volunteers with proven fertility and the other group consisted of patients visiting the general infertility clinic. In each woman, 2D or 3D TVS was performed in the early follicular phase (day 2, 3 or 4) of the menstrual cycle to measure the number of antral follicles (2-10 mm). RESULTS: Intraobserver reproducibility was calculated from follicle counts using 3D TVS in 41 women. The intraclass correlation coefficient was 0.99 and the 95% coverage interval of the difference (CID) was -3.2 to +3.2. Interobserver reproducibility was assessed from both 2D (n = 37) and 3D (n = 49) TVS-based follicle counts. An interclass correlation coefficient of 0.98 was found for both methods. The 95% CID was -5.0 to +4.1 for 2D and -5.6 to +5.7 for 3D measurements. The latter CID appeared to increase in the higher range of counts. Finally, the degree of agreement between 2D and 3D TVS counts (n = 76) was characterized by a 95% CID of -5.3 to +8.3. This coverage interval widened when higher numbers of follicles were counted. With the exception of the between-method analysis, kappa values indicated overall that follicle counts will hardly change from one category to another when repeatedly carried out. CONCLUSIONS: Determination of antral follicle numbers by both 2D and 3D TVS is adequate with regard to the intra- and interobserver reproducibility. The between-method reproducibility of follicle counts measured both by 2D and 3D ultrasound is moderate. When higher follicle counts are observed both interobserver and between-method reproducibilities tend to decline. If used in categorical classifications, ultrasound-based follicle counts appear to have a high level of agreement between and within observers.

Female↗
PubMed1999

Comparison between intracytoplasmic sperm injection and in-vitro fertilization (IVF) with high insemination concentration after total fertilization failure in a previous IVF attempt.

The aim of this prospective study was to evaluate whether couples with total fertilization failure in a previous in-vitro fertilization (IVF) attempt should be offered an additional IVF treatment with elevated insemination concentration or should be treated with intracytoplasmic sperm injection (ICSI). In 23 cycles 228 sibling metaphase II (MII) oocytes were randomly divided: 143 and 85 oocytes were utilized for ICSI and IVF respectively. Of the 143 injected (ICSI) oocytes, 90 (62.9%) were normally fertilized (two pronuclei), whereas 21 (14.7%) oocytes were damaged by the ICSI procedure. Of the fertilized oocytes 72 (80%) developed into transferable embryos. No fertilization at all was observed in the 85 sibling MII oocytes which were inseminated (P < 0.001). In all 23 cycles at least one embryo, obtained by ICSI, could be replaced. Eight pregnancies were achieved of which six resulted in the delivery of nine healthy children. In conclusion, for couples with no or almost no fertilization of oocytes in previous IVF attempts, ICSI appeared to be far superior to an additional IVF attempt with further elevated insemination concentrations.

Adult↗
PubMed1998

Fetal growth retardation as a cause of impaired ovarian development.

Low birthweight has been associated with diseases and disorders later in life. It has been suggested that this is caused by the impaired development of abdominal organs, especially in cases of growth retardation. Besides general malnutrition of the fetus, preferential bloodflow to the heart and brain may further deprive organs, such as liver, pancreas and kidney, of nutrients. As a result these organs may not develop properly. Anatomically, the ovary is situated close to the kidney and it is very likely that, similar to the kidney, ovarian development can be negatively affected by intra-uterine growth retardation. Placental insufficiency, which is an important cause of severe intra-uterine growth retardation, was used as a model to investigate this hypothesis. In the present study, the volume percentages of primordial follicles in the ovaries of four severely growth-retarded fetuses of different gestational ages are compared to those of four age-matched controls. It is found that these volume percentage in growth-retarded fetuses were significantly lower than those observed in the age-matched controls. It can be concluded that ovarian development is impaired in intra-uterine growth-retarded fetuses. These findings further suggest that, as a result of the premature loss of follicles, females with low birthweights may encounter fertility problems later in life.

Birth Weight↗
PubMed1990

Influence of complement on sperm motility.

Isolated sperm from normo-, oligo- and astheno-spermic men were incubated for 20 h in medium supplemented with 8% heat-inactivated or untreated human serum, and in medium with heated or untreated serum deficient in complement factor C3. Before and after incubation, sperm motility was assessed by means of a computer-assisted semen analyser. The results did not show significant differences between the motility of sperm incubated in heated or untreated serum. It is concluded that heating of homologous serum is not necessary for preserving sperm motility and in some cases may even be disadvantageous.

Blood↗
PubMed1984

The treatment of rupture of the pregnant uterus. Analysis of 93 cases treated in a rural hospital in Zambia.

In this study 93 cases of uterine rupture, treated in a rural hospital in Zambia have been analyzed. Clinical characteristics and mortality rate were found to be comparable to those reported in other series from developing countries. An attempt was made to compare the outcome of various surgical procedures. No statistically significant differences were found between the mortality rates after repair, subtotal and total hysterectomy (12%, 13% and 28%, respectively). A survey of recent literature on the treatment of uterine rupture in developing countries revealed a wide divergence of opinions and criteria of selection, precluding reliable comparisons. A proposition for individualized treatment is outlined, concluding that repair should be performed when suitable but that hysterectomy is preferable when the tear is extensive, bruised and contaminated.

Developing Countries↗