Biomedical subjects

W Küpker

Publications and source records attributed to W Küpker.

At least 19 recordsLinked to original sources

PubMed1998

Principles of mammalian fertilization.

The principles of mammalian fertilization are defined in relation to studies of the intracytoplasmic injection of spermatozoa into human oocytes (ICSI). Sections are included on the production of mature oocytes and mature spermatozoa, sperm-oocyte interaction, and formation of the pronucleate oocyte. Current concepts in gametogenesis are discussed, including spermiogenesis, oogenesis, the biology and penetration of the zona pellucida including capacitation and the acrosome reaction, gamete fusion, the block to polyspermy and growth of the pronucleus. A concluding section relates the normal events of fertilization to those occurring after ICSI and discusses various types of anomalies found in the oocyte after ICSI.

Animals↗

PubMed1998

Ultrastructure of gametes and intracytoplasmic sperm injection: the significance of sperm morphology.

The aim of this study was to determine characteristic malformations of sperm ultrastructure in patients with severe subfertility undergoing intracytoplasmic sperm injection (ICSI). Although light microscopy (LM) can reveal major abnormalities of the three parts of the spermatozoon (head, mid-piece and flagellum), the various cell organelles of the spermatozoon and their fine structure remain unevaluated by LM. Insight into the submicroscopic organization of the spermatozoon and its complex organellar system may contribute to a better understanding of the preconditions for success or failure of fertilization. An in-depth evaluation of semen quality by transmission electron microscopy (TEM) can improve the diagnosis of male subfertility and can give substantial information about the fertilizing competence of spermatozoa. Thus, in this study 56 ejaculated sperm samples from patients with severe male subfertility or previous failed attempts at in-vitro fertilization were assessed by LM and TEM prior to ICSI to evaluate the most important sperm defects causing extreme subfertility. LM analysis was performed according to World Health Organization criteria. It could be confirmed that severe head defects are mostly involved in long-term infertility and fertilizing failure in classical IVF treatments. The most frequent head defects are disorders of the nuclear membranes and the acrosomal cap and disorganization of the chromatin structure. These defects of sperm fine structure seem to be associated with dysfunctional sperm-oocyte recognition, binding and fusion with the oolemma. Chromatin alterations and signs of decondensation or karyolysis are frequently associated with a deterioration of the nuclear membranes and may be due to impaired spermiogenesis. However, our results and the success of ICSI proved that severe sperm defects have no predictive value and do not impair the fertilization process, and also that the maturity of spermatozoa does not play an important role. Fine structure analysis revealed the pleiomorphology and heterogeneity of human spermatozoa.

Female↗

PubMed1997

A new indication for an intracytoplasmic sperm injection procedure outside the cases of severe male factor infertility.

OBJECTIVE: To show the success of intracytoplasmic sperm injection (ICSI) in cases of a low number of oocytes retrieved. STUDY DESIGN: 715 microinjection cycles, which were performed at our center, were analyzed retrospectively. RESULTS: Within the analyzed cycles, there were 50 cycles with less than four oocytes retrieved. Twelve, 18, and 20 cases were treated with one, two, and three oocytes, respectively. The rate of metaphase II oocytes injected and subsequently fertilized, and intact oocytes was similar in the three groups. The transfer rate was not significantly different from those cases with more than three oocytes (84% vs. 94%). Therefore, the rate of fertilization failure was not higher in the low-number group. The number of embryos transferred was statistically significantly lower in the group with one and two oocytes compared to the group with three oocytes (1, and 1.31 vs. 2.27; P < 0.01) and the group of all patients (2.63; P < 0.01), as well as between the group of less than four oocytes and all patients (1.63 vs. 2.63; P < 0.01). There was no statistically significant difference between the pregnancy rates of the three groups (36.4% vs. 20% vs. 22.2%), and also no difference was found between the group with less than four oocytes and the data of all patients (22% vs. 26.9%). CONCLUSION: In our opinion, these data show that ICSI guarantees a successful treatment even if only as many oocytes are present as embryos are planned to be transferred, i.e. three embryos. This has been accepted to be a new indication in our center. Therefore it should be possible to stimulate patients mildly, with e.g. clomiphene citrate, to avoid unnecessary hyperstimulation syndromes, and to lower the cost of hormonal superstimulation.

Adult↗

PubMed1997

Pregnancy outcome after assisted fertilization--a short survey.

Since 1992, intracytoplasmic sperm injection has been established as the treatment of choice for severe male subfertility. Worldwide results with regard to fertilization, pregnancy and pregnancy outcome, collected by the EHSRE Task Force on ICSI, are reported in this short survey. Aspects of genetic inheritance that are of major concern are addressed briefly.

Data Collection↗

PubMed1996

Hormone profiles under ovarian stimulation with human menopausal gonadotropin (hMG) and concomitant administration of the gonadotropin releasing hormone (GnRH)-antagonist Cetrorelix at different dosages.

PURPOSE: The premature LH surge in ART programs seems to be avoided by daily administration of the GnRH-antagonist Cetrorelix during the midcycle phase in controlled ovarian hyperstimulation with hMG. The dosage necessary for sufficient suppression of the pituitary gland is not yet defined. METHODS: To elucidate this question three daily dosages (3, 1, 0.5 mg) were administered and the hormone profiles obtained as well as the number of oocytes retrieved, the fertilization rate, and the consumption of HMG were compared. RESULTS: No premature LH surge could be observed at any of the three dosages administered. Both gonadotropins were deeply suppressed. The fertilization rates of the oocytes obtained were 45.3% in the 3-mg group, 53.1% in the 1-mg group, and 67.7% in the 0.5-mg group. The average uses of hMG ampoules were 30 in the 3-mg group, 27 in the 1-mg group, and 26 in the 0.5-mg group. CONCLUSIONS: Cetrolix, 0.5 mg/day, administered during the midcycle phase of controlled ovarian hyperstimulation with hMG is enough to prevent completely the premature LH surge. Perhaps even lower dosages would be sufficient. Regarding fertilization rates and use of hMG, the lower dosage seems to be the most favorable.

Adolescent↗

PubMed1996

Small-diameter laparoscopy (SDL) using a microlaparoscope.

PURPOSE: To determine the ability of new sub-2.0-mm-diameter microlaparoscopes to be used for diagnostic laparoscopy, 28 small-diameter laparoscopies (SDL) were performed during a 4-month-period. METHODS: These cases were performed under general anesthesia, with immediate follow-up confirmation with conventional laparoscopic equipment. An additional 13 SDL procedures were performed under analgosedation plus local anesthesia and were well tolerated by the patients. RESULTS: For the cases performed with conventional laparoscopic control, the visualization results were comparable in 27 of 28 procedures. In the nongeneral anesthesia SDL group, patients were highly satisfied and reported less post-procedural discomfort and minimal scar formation due to the smaller access ports. In this study, two types of microlaparoscopes were used. CONCLUSIONS: While both were adequate, the newer high-resolution microlaparoscope delivered an image much more similar to that which conventional laparoscopy and required little or no change in technique in order to obtain images. With the advent of this new endoscope technology with optics performance comparable to that of conventional laparoscopes, SDL has demonstrated to be a useful procedure for certain clinical indications.

Evaluation Studies as Topic↗

PubMed1996

[Significance of tumor necrosis factor alpha (TNF-alpha) in endometriosis].

Macrophage-derived substances such as cytokines and growth promoting factors are known to be present in the peritoneal fluid of women with endometriosis. Active endometriosis of the peritoneum is characterised by hypervascularization and neoangiogenesis. TNF-alpha is a pleiotropic cytokine also involved in angiogenesis and immunoregulation. Our question was to determine whether there are differences in the peritoneal TNF-alpha concentrations in women with various degrees of active and inactive endometriosis. We found that TNF-alpha concentrations were higher in the peritoneal fluid of women with endometriosis than in the peritoneal fluid of those without. TNF-alpha concentrations were higher in cases of active endometriosis than in cases of inactive endometriosis. The highest concentrations could be detected in women with severe endometriosis (stage III and IV rAFS).

Adult↗

PubMed1996

Results of cytogenetic analysis in men with severe subfertility prior to intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is increasingly becoming the treatment of choice for severe male subfertility. Cytogenetic evaluation of men with andrological subfertility reveals an increased incidence of chromosomal abnormalities when compared with the normal population. We performed chromosomal analysis on the male partners of 32 couples referred for andrological subfertility. In two of these men, constitutional chromosomal translocations were diagnosed prior to ICSI [(45,XY,t(21;22)(p11;q11) and 46,XY,t(22;Y)(p11;q12)]. Since ICSI bypasses many potential barriers of fertilization, successful pregnancy can be achieved despite the presence of severely impaired spermatozoa in a population at high risk for chromosomal aberrations. It is well known that the presence of a chromosomal aberration plays a significant role in partial or complete spermatogenic arrest. ICSI does not seem to increase the risk of fetal chromosomal abnormalities when a spermatozoon from a chromosomally normal male is used. To exclude a higher risk for spontaneous abortion and fetal chromosomal abnormalities, we advocate cytogenetic screening of males with severe male subfertility who opt for ICSI.

Adult↗

PubMed1996

Comparison of cryopreservation of supernumerary pronuclear human oocytes obtained after intracytoplasmic sperm injection (ICSI) and after conventional in-vitro fertilization.

A comparison was made of pronuclear stage human oocytes obtained either after classical in-vitro fertilization (IVF) or after intracytoplasmic sperm injection (ICSI). After ICSI or IVF, three fertilized oocytes from each patient were kept in culture for a further 24 h before embryo transfer. The surplus oocytes were cryopreserved using the 'open freezing system' and 1,2-propanediol and sucrose as cryoprotectants. A cohort of 817 and 1626 oocytes in pronuclear stage were frozen after IVF and ICSI respectively. Of these, 333 and 744 zygotes have been thawed, of which 78 and 76.5% were morphologically intact zygotes after IVF and ICSI respectively. From the 204 (ICSI) and 89 (IVF) zygote transfers performed, 34 (17%) and 18 (20%) pregnancies were established. Both groups showed a similar abortion rate of approximately 20%. It is concluded that pronuclear stage oocytes resulting from ICSI can be successfully frozen/thawed and the survival and pregnancy rates achieved are comparable to those for zygotes obtained after IVF.

Cryopreservation↗

PubMed1996

The combination of two semen preparation techniques (glass wool filtration and swim-up) and their effect on the morphology of recovered spermatozoa and outcome of IVF-ET.

The aim of this prospective study was to relate sperm quality, especially sperm morphology, to the outcome of IVF results, when glass wool filtration (GWF) and swim-up were used in combination for the preparation of spermatozoa. A total of 60 ejaculates were analysed. GWF was compared with glass wool filtration/swim-up (GWF-SU) by using aliquots from the same semen samples to increase the precision of the comparison and to establish the cumulative effect of these two semen preparation methods on the morphology of the recovered spermatozoa. Sperm parameters were examined in native semen, in semen preparation samples after GWF and GWF-SU. The mean percentages for motility, morphology and velocity were improved significantly over those in fresh semen only when GWF-SU was used. GWF alone resulted only in a significantly higher recovery of motile spermatozoa. In semen preparation, 10% of spermatozoa with normal morphology appeared to be the cut-off point as there was a significantly higher recovery in fresh semen samples containing > 10% morphologically normal spermatozoa after GWF-SU. Outcome of IVF-ET following preparation with GWF-SU showed better results in comparison to the swim-up procedure alone, though this difference was not statistically significant. The cut-off point was also > 10% morphologically normal spermatozoa. Improvement in all aspects of IVF-ET occurred when native semen contained > 10% morphologically normal spermatozoa. It is concluded that GWF alone did not produce significantly better results but, in combination with swim-up, it resulted in significantly better sperm morphology and in an improved outcome of IVF-ET for fresh semen samples with > 10% morphologically normal spermatozoa.

Adult↗

PubMed1996

Assisted fertilization--treatment of severe male subfertility.

Since 1992 direct injection of a single spermatozoon into the cytoplasm of the oocyte (ICSI) has developed as the treatment of choice in cases of severe male subfertility. The ICSI procedure displays high fertilization and pregnancy rates in cases of extreme oligoasthenoteratozoospermia. In combination with sperm aspiration from the epididymis or sperm retrieval by testicular sperm extraction, fertilization is possible even in cases of azoospermia. To date, a couple of thousand children have been born after ICSI. Despite the criticism about the lack of natural selection while breaking the zona pellucida and the cytoplasmic membrane with the injection pipette, there has been no increased incidence of malformations and chromosomal abnormalities.

Congenital Abnormalities↗

PubMed1996

[Risks of expectant management of extrauterine pregnancies with low HCG titers and absent clinical symptoms].

We report on 4 cases of ectopic pregnancy with low HCG-levels and lack of clinical symptoms, in which expectant management was performed. Advantages and disadvantages of the procedure are discussed. While one can find a variety of therapeutical concepts in the literature such as conservative medical treatment alone or in combination with laparoscopy or expectant management, we dispose to prefer a fertilization providing gentle operative laparoscopic assessment as the treatment of choice in all cases of ectopic pregnancy. In all 4 cases operative laparoscopy had to be performed after an interval of expectance when the patients displayed sudden severe clinical symptoms.

Adult↗

PubMed1996

Use of assisted reproductive techniques for treatment of ejaculatory disorders.

Ejaculatory disorders can interfere with the fertility of young adults who suffer from spinal cord injury, have type I diabetes mellitus or have undergone retroperitoneal or intrapelvic operations. Following an overview of causes and treatment of ejaculatory disorders, the data of our centre are presented. From a group of 37 patients with genuine loss of seminal emission, 15 men and their wives were offered a combined treatment of rectal probe electro-ejaculation and artificial reproductive techniques. No serious complications occurred. During 40 cycles with intracorporeal insemination and 11 cycles with extracorporeal fertilization techniques, seven pregnancies were achieved, representing a pregnancy rate of 46% per couple and 14% per cycle for all cycles. Five healthy children were born, all following extracorporeal insemination. The 'take-home baby rate' for this population and for this technique is 45%. In vitro fertilization (IVF) led to one birth, intracytoplasmic sperm injection (ICSI) achieved four live births out of three pregnancies, one being a twin gestation. Since our successes are due to the use of extracorporeal insemination techniques, these are now incorporated in a new, more rational treatment protocol.

Ejaculation↗

PubMed1995

Mini-swim-up: a new technique of sperm preparation for intracytoplasmic sperm injection.

PURPOSE: The male factor is nowadays one of the major problems in the treatment of infertility. New methods of assisted fertilization such as the intracytoplasmic sperm injection (ICSI) show better fertilization and pregnancy rates than classical IVF. METHOD: In this study, we present a new technique of sperm preparation: the "mini-swim-up." CONCLUSION: This technique, used in conjunction with the ICSI procedure, improves pregnancy and fertility rates in cases of severe oligoasthenoteratozoospermia.

Cell Separation↗

PubMed1995

Morphology in intracytoplasmic sperm injection: preliminary results.

PURPOSE: Direct intracytoplasmic sperm injection (ICSI) is a successful treatment of severe male subfertility. Conventional in vitro fertilization shows poor pregnancy rates especially in cases of severe teratozoospermia. The objective was to determine if severe morphological defects of spermatozoa in oligoasthenoteratozoospermia (OAT) have any impact on the fertilization process in ICSI and if there are any specific morphological characteristics in nonfertilized oocytes after the ICSI procedure. METHODS: Ejaculates and nonfertilized oocytes were investigated by electron microscopy. CONCLUSIONS: The lack of intracytoplasmic sperm-oocyte interaction, not severe sperm defects, displays the most critical role in the fertilization process. Clinical data with fertilization rates of 66% and pregnancy rates of 23.3% confirm the fertilization capacity of severely

Acrosome↗

PubMed1995

Preserved pituitary response under ovarian stimulation with HMG and GnRH antagonists (Cetrorelix) in women with tubal infertility.

OBJECTIVE: To examine the pituitary response in patients undergoing short-term application of the GnRH antagonist Cetrorelix in the mid-cycle phase for hypophysial suppression of premature LH surges within an IVF-program. DESIGN: Twenty patients suffering from primary or secondary tubal infertility were stimulated with hMG from cycle day 2. From day 7 till ovulation induction Cetrorelix was administered in two different dose regimens (15 patients 3 mg s.c. daily; 5 patients 1 mg s.c. daily). Three hours before ovulation induction a GnRH test was performed using 25 micrograms of native GnRH and the pituitary response examined by measurement of the serum LH concentration after 30 min. RESULTS: Premature LH surges could be avoided in the 3-mg group and in the 1-mg group, respectively. Due to this, none of the cycles had to be cancelled. Oestradiol profiles and ultrasound demonstrated a satisfactory follicular maturation. All patients showed pronounced suppression of the serum LH levels before ovulation induction. The mean increase of serum LH due to the performed GnRH test was 10 mIU/ml for the 3-mg group, while the average maximum in the 1-mg group was about 32.5 mIU/ml. CONCLUSIONS: The pituitary response is preserved by the treatment with the GnRH antagonist Cetrorelix. The extent of suppression of the adenohypophysis, as expressed by the different reactions on GnRH test, can be modulated by the dosage administered. This should allow ovulation induction by GnRH or one of its agonists instead of hCG, which could be beneficial in patients at high risk of Ovarian Hyperstimulation Syndrome (OHSS) and those suffering from Polycystic Ovary Disease (PCOD).

Adult↗

PubMed1995

[Triplet pregnancy after intracytoplasmic sperm injections].

Morphology of the spermatozoa is one of the major criteria in severe male subfertility. We report on a case of severe Oligoasthenoteratozoospermia in which a triplet pregnancy could be achieved after intracytoplasmic sperm injection (ICSI). After treatment with GnRH-analogues/HMG/HCG seven oocytes of metaphase II could be retrieved and injected. Three of them fertilised and were transferred as four-cell stage embryos after two days. Seven weeks later an intact triplet pregnancy could be detected by ultrasonography. The severe sperm defects in this case were evaluated with the technique of electron microscopy. Ultramorphology of spermatozoa appears to have an important predictive value for fertilisation and pregnancy in classical IVF. Its value for the assisted procreation techniques such as ICSI remains to be investigated.

Adult↗

PubMed1995

[GnRH antagonists in gynecology: initial results within the scope of controlled ovarian hyperstimulation].

OBJECTIVE: Applicability of the GnRH-antagonist Cetrorelix within controlled ovarian hyperstimulation (COH) to avoid the premature LH-surge should be examined. METHODS: 35 patients suffering from tubal infertility were stimulated for In Vitro Fertilization (IVF) by human menopausal gonadotrophins (HMG) and concomitant administration of Cetrorelix in different dosages (3 mg, 1 mg, 0,5 mg). RESULTS: No premature LH-surge could be observed. CONCLUSIONS: Short term administration of the GnGR-antagonists avoids the occurrence of a premature LH-surge.

Adult↗