A new Dutch Law regulating provision of identifying information of donors to offspring: background, content and impact.

In 2004 a law was introduced in The Netherlands, which gives offspring conceived by semen or oocyte donation the right to know the identity of the donor. The law also regulates the provision of other information concerning the donor to the offspring, their parents or their general practitioner. With the introduction of this law, a choice has been made in which the wish of offspring prevails above others involved. Donors can no longer claim absolute anonymity; they are anonymous at the time of donation, but if a child aged > or =16 years requests information the donor may now be traced. During 15 years of debate on the abolition of donor anonymity the number of donors decreased by >70% and the number of semen banks by 50%. We describe the debate which led to the law, the characteristics of the law itself and note some of the probable and possible consequences for donor offspring, parents, donors and semen banks.

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.

Effect of cumulus cell removal of in vitro matured bovine oocytes prior to in vitro fertilization on subsequent cleavage rate.

The aim of this study is to identify the effect of cumulus cells removal prior to the in vitro fertilization of matured bovine oocytes on cleavage rate. Denuded, matured oocytes were fertilized in presence or absence of loose cumulus cells, cumulus cell conditioned IVF medium (CCCM), charcoal-treated CCCM and charcoal-treated CCCM supplemented with progesterone at a final concentration of 150 ng/ml. After 18 h of incubation with sperm, the presumptive embryos were cultured on a BRL monolayer and the percentage of cleaved embryos was evaluated on Day 4. Removal of cumulus cells prior to IVF significantly reduced the cleavage rate (25% for denuded oocytes versus 56% for cumulus-oocyte complexes (COCs)). The addition of loose cumulus cells partially restored the effect of denudation (cleavage rate: 37% for denuded oocytes supplemented with loose cumulus cells versus 27% for denuded oocytes and 58% for COCs). CCCM also had a positive effect on the cleavage rate of oocytes denuded prior to IVF (36% for denuded oocytes fertilized in CCCM versus 14% for denuded oocytes). Treating the CCCM with charcoal resulted in complete loss of its effect on cleavage rate (18% for denuded oocytes fertilized in charcoal-treated CCCM versus 34% for denuded oocytes fertilized in CCCM). The addition of progesterone to charcoal-treated CCCM partially restored the reduction of the cleavage rate caused by charcoal treatment (27% for denuded oocytes fertilized in charcoal-treated CCCM supplemented with progesterone versus 14% for denuded oocytes fertilized in charcoal-treated CCCM and 36% for denuded oocytes fertilized in CCCM). In conclusion, removal of cumulus cells prior to IVF adversely affects the cleavage rate through loss of a factor secreted by these cells. This factor probably is progesterone.

Temporal factors in resource dilemmas.

The conflict between present and future consumption lies at the heart of resource dilemmas (RDs), yet the role of time has received little attention in this research area. Emphasis was on factors related to the social rather than the temporal conflict inherent in an RD. We propose a model that deals explicitly with the temporal distribution of outcomes. The model combines three basic elements: a simple algebraic model, representing the RD's payoff structure; a growth function, reflecting the autonomous growth of the resource pool; and a discount function, describing how the temporal distance of outcomes affects their perceived value. The model provides a comprehensive framework for understanding the role of temporal factors in RD situations. It enables us to identify four relevant temporal RD characteristics (people's discount rates, their time horizon, the inter-trial delay, and the pool's growth rate) and to describe how these would be expected to affect people's tendency to cooperate. Theoretical, methodological and practical implications of the work are briefly discussed.

Paternal occupational exposures and embryo implantation rates after IVF.

OBJECTIVE: To investigate any influence of paternal occupational exposures on implantation rates after IVF. DESIGN: Cohort study of couples who sought IVF treatment. SETTING: University Hospital Utrecht, The Netherlands. PATIENT(S): The study population was composed of 726 couples pursuing IVF treatment. INTERVENTION(S): Only the earliest IVF treatment cycle with ET was selected for the analysis. All couples filled in a generic questionnaire on lifestyle factors and details about their occupation. In addition, more detailed exposure information was obtained for pesticides with use of job-specific questionnaires and a subsequent telephone interview. MAIN OUTCOME MEASURE(S): The implantation rate was defined as the number of gestational sacs seen with ultrasound at 6-7 weeks of pregnancy, divided by the number of embryos replaced. RESULT(S): A significantly reduced implantation rate was seen among couples with male partners working in occupations with presumably high levels of organic solvent exposure. Conversely, paternal pesticide exposure was significantly associated with an increased implantation rate. Paternal exposures to metal dust or fumes and welding fumes were not related to the probability of implantation. CONCLUSION(S): The findings suggested that paternal organic solvent exposure decreased the implantation rate among couples undergoing IVF-ET treatment.

ESHRE guidelines for good practice in IVF laboratories. Committee of the Special Interest Group on Embryology of the European Society of Human Reproduction and Embryology.

Education has always been a priority for the European Society of Human Reproduction and Embryology (ESHRE). Many efforts have been dedicated to promoting knowledge of techniques, procedures and strategies in order to ensure use of the highest quality practices in reproductive medicine. The need to develop a set of guidelines was a logical consequence that found its first expression in 1990, when Focus on Reproduction (vol. 1, pp. 10-38) published the first guidelines which were distributed among the membership. Five years later a new, more complete edition with several novel techniques and developments appeared in Human Reproduction (vol. 10, pp. 1246-1271). Both have proved to be invaluable references. Five more years have now passed. The necessity to produce current guidelines for good IVF laboratory practice has provided the strongest motivation. This originated from the increasing awareness that embryologists have a duty to prevent unintentional incidents that might result from poor practice in the laboratory. Therefore, the Embryology Special Interest Group (SIG) undertook to draw up guidelines aimed at giving support and guidance to the laboratory staff. All the aspects required to provide a safe working system were taken into consideration by members of the SIG and their effort produced this document. We hope that it will assist staff in achieving the best clinical outcome for their patients.

Pesticide exposure and decreased fertilisation rates in vitro.

The effect of paternal occupational exposures on fertilising ability was investigated in 836 couples who sought in-vitro fertilisation treatment. Fertilisation rates were significantly decreased for couples with paternal pesticide exposure.

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.

Occupationally related exposures and reduced semen quality: a case-control study.

OBJECTIVE: To determine whether there is an association between abnormal semen parameters and occupational exposures to organic solvents, metals, and pesticides. DESIGN: Case-control study using three case groups based on different cutoff values for semen parameters and one standard reference group. SETTING: University Hospital Utrecht and University Hospital Rotterdam, the Netherlands. PATIENT(S): Male partners of couples having their first consultation at the two infertility clinics (n = 899). INTERVENTION(S): Men provided at least one semen sample. Occupational exposure was assessed with use of job-specific questionnaires, a job exposure matrix, and measurements of metals and metabolites of solvents in urine. MAIN OUTCOME MEASURE(S): Standard clinical semen analyses were used to define case groups and controls. RESULT(S): An association between aromatic solvents and reduced semen quality was demonstrated, irrespective of the exposure assessment method used. The associations were stronger if the case definition was based on stricter cutoff values for semen parameters. Risk estimates were higher if the analysis was restricted to primary infertile men. Exposure to other pollutants at the workplace was not associated with impaired semen quality. CONCLUSION(S): The findings indicated an association between aromatic solvent exposure and impaired semen parameters.

Controlled ovarian hyperstimulation and intrauterine insemination for treating male subfertility: a controlled study.

In this randomized crossover trial we investigated whether the use of controlled ovarian hyperstimulation with low-dose human menopausal gonadotrophin in couples with male subfertility leads to a higher probability of conception when intrauterine insemination (IUI) is applied. We also investigated whether the efficacy of IUI in natural or stimulated cycles was related to the severity of male subfertility. Seventy-four couples completed 308 treatment cycles. Thirteen pregnancies occurred after IUI in a natural cycle (pregnancy rate per completed cycle: 8.4%) and 21 after IUI in a stimulated cycle (pregnancy rate per completed cycle: 13.7%). The difference between the two treatment modalities was not statistically significant. The efficacy of IUI in stimulated cycles was related to the severity of the semen defect. In couples with a total motile sperm count < 10 x 10(6), ovarian stimulation did not improve treatment outcome, while it did in couples with a total motile sperm count > or = 10 x 10(6). Compared with the expected chance of conceiving spontaneously without treatment, both natural and stimulated cycles improved the probability of conception. We conclude that, for the group as a whole, ovarian stimulation did not improve the probability of conception. However, in couples with less severe semen defects, ovarian stimulation did improve the probability of conception.

Uniqueness of limit cycles in models for microparasitic and macroparasitic diseases.

The aim of this paper is to prove the uniqueness of isolated periodic solutions (i.e. limit cycles) in two simple models for microparasitic and macroparasitic diseases. Both models are described by systems of planar autonomous ordinary differential equations. After transformation of these systems to generalized Liénard systems, we will apply a modified theorem of Zhang and Dulac's criterion to prove the uniqueness of limit cycles.

Protein C inhibitor may modulate human sperm-oocyte interactions.

Protein C inhibitor (PCI) is a heparin-binding plasma serine protease inhibitor that was originally identified as an inhibitor of activated protein C. PCI has a broad protease specificity, inhibiting several proteases in hemostasis and fibrinolysis by acting as a suicide substrate. Recently it has been reported that proteases of the reproductive system, such as acrosin, prostate-specific antigen, and tissue kallikrein, can also be effectively inhibited by PCI. However, a direct relation between PCI and physiological events during fertilization has not yet been established. An attempt was made to monitor and localize the inhibition of the sperm protease acrosin by PCI. Localization experiments for PCI on epididymal spermatozoa showed that PCI is present on the acrosomal cap of human spermatozoa, which demonstrates the early presence of PCI in the male reproductive tract. Induction of the acrosome reaction in ejaculated human spermatozoa resulted in the disappearance of PCI from the plasma membrane overlying the acrosomal head and the appearance of a strict distribution at the equatorial segment of human spermatozoa. The activity of acrosin in sperm extracts could be effectively inhibited by PCI. Zona-binding assays showed that active PCI is able to block sperm-egg binding in a concentration-dependent manner. The combination of the potent inhibition of acrosin and sperm-egg binding by PCI and the localization studies suggested that PCI may protect spermatozoa against premature acrosome reaction and degradation, thereby modulating the acrosin activity so that it can coincide with binding to the oocyte.

[Exposure to pseudo-estrogens and the quality of sperm]. / Blootstelling aan pseudo-oestrogenen en spermakwaliteit.

Some synthetic chemicals and natural compounds occurring in vegetables or animal food products mimic endogenous hormones, especially oestrogens, or may have a general action of disturbing hormonal status. It is assumed that intrauterine exposure to these compounds may have an adverse effect on development, differentiation and function of the genital organs of the male foetus. In a worldwide discussion a supposed drop in human sperm quality is related to foetal exposure to chemicals with oestrogen activity. Experimental animal evidence suggests that foetal exposure to compounds with oestrogenic activity may influence reproductive capabilities. In addition chemicals such as diethylstilbestrol (DES) in humans and dichlorodiphenyltrichloroethane (DDT) in wildlife influence the reproductive system. There is no conclusive evidence of decreasing semen quality in general.

General ageing and ovarian ageing.

The age related decrease in female fertility is associated with a decrease in follicle numbers and oocyte quality. Meiotic division errors, mitochondrial DNA mutations and ageing itself have been suggested to play a part in the age associated reduction in oocyte quality. During the past decades several hypothesis have been proposed, trying to explain the underlying mechanisms. However, none of them is yet conclusive. This review will consider the main hypotheses regarding the age related reduction in oocyte quality. This will be reviewed together with recent results of studies analysing a possible relationship between ageing and ovarian ageing. On the basis of our own results and those presented in the literature, it is concluded that ovarian ageing may only be related to specific aspects of general ageing.

[Male subfertility, modern reproduction techniques and transmission of genetic abnormalities]. / Mannelijke subfertiliteit, moderne voortplantingstechnieken en het doorgeven van genetische afwijkingen.

Somatic cells of males with azoospermia or oligozoospermia (sperm density < 20 million sperm cells/ml) were found to contain increased percentages of chromosomal abnormalities. Subfertile males with a normal somatic karyogram were found to have increased rates of aneuploidy in sperm. This creates risks for the offspring after fertilization with intracytoplasmatic sperm injection (ICSI). Certain gene mutations on the Y chromosome cause severe oligo- or azoospermia and will, in case of successful reproduction with ICSI, be transmitted to male offspring in 100% of the cases. The same holds true, irrespective of sex, of mutations responsible for cystic fibrosis. In non-random groups of ICSI pregnancies, higher proportions of de novo sex-chromosomal abnormalities have been found than expected. In addition, there are increased proportions of paternally inherited structural autosomal anomalies. Extrapolation of the findings is not yet possible, however.

Intracytoplasmic sperm injection (ICSI) and chromosomally abnormal spermatozoa.

An infertile couple was referred for intracytoplasmic sperm injection (ICSI) because of primary infertility and oligoasthenoteratozoospermia (OAT) in the male. It was observed that although the sperm cells presented with an unusual head size and multiple tails they were able to fertilize the oocytes after ICSI. Subsequent molecular cytogenetic analysis demonstrated de-novo chromosome abnormalities in virtually all sperm cells with 40% diploidy and 24% triploidy in addition to aneuploidy for the sex chromosomes.

Age-dependent decrease in embryo implantation rate after in vitro fertilization.

OBJECTIVE: To investigate the relation between the implantation rate per embryo after replacement in IVF-ET in relation to female age. DESIGN: Retrospective study using linear and biphasic models in a multivariate analysis. SETTING: Academic tertiary care institution. INTERVENTION(S): In vitro fertilization-ET and determination of gestational sacs at 6 to 7 weeks of pregnancy buy ultrasound. MAIN OUTCOME MEASURE(S): Implantation rate as defined by the number of gestational sacs per embryo replaced. RESULT(S): Woman's age and embryo morphology were strongly related to the implantation rate, indication for IVF-ET and cycle rank number also were related significantly but less strongly. A linear model was built describing the decrease in implantation rate with age, resulting in a decrease of approximately 7%. A biphasic model was tested also and performed significantly better, resulting in a yearly decrease of > 20% after 37 years of age. CONCLUSION(S): The most important independent factors related to the ability of embryos to implant are female age and embryo morphology. The best way to describe the relation with female age is biphasic model with a discontinuity at approximately 37 years of age.