Doctoral Degrees (Obstetrics and Gynaecology)

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Browsing Doctoral Degrees (Obstetrics and Gynaecology) by Author "Windt, Marie-Lena"

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    Human gamete micromanipulation and intracytoplasmic sperm injection (ICI) : its impact on severe male infertility
    (Stellenbosch : Stellenbosch University, 2000-12) Windt, Marie-Lena; Kruger, T. F.; Stellenbosch University. Faculty of Medicine & Health Sciences. Dept. of Obstetrics & Gynaecology.
    ENGLISH ABSTRACT: Intracytoplasmic sperm injection (ICSI) introduced a revolutionary way of treatment for male factor infertility. With the exception of some cases of non-obstructive azoospermia, all other male factor infertility cases have the potential to be successfully treated with ICS!. The only prerequisite seems to be the presence of a motile or viable immotile sperm cell for each oocyte. In this study we report on our own experience with the development and implementation of the ICSI method in the Reproductive Biology Unit at Tygerberg Hospita!. An analysis of 5 years of ICSI experience showed that semen parameters, sperm morphology, motility and concentration did not influence fertilization and pregnancy rates adversely. In most cases, patients who could not be treated with in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT), due to poor semen parameters or fertilization failure, were treated successfully with ICS!. Even a case of globozoospermia was treated successfully with ICS!. Testicular spermatozoa, fresh or frozen-thawed, also resulted in excellent fertilization and pregnancy rates. Cryopreservation of testicular samples facilitated the management of the infertile couple, aiding the coordination of the recovery of vital gametes from both partners and also limiting the repetition of testicular biopsies. Incubation (maturation) of testicular spermatozoa also induced an enhancement in pregnancy rates. It can be concluded that ICSI proved to be a treatment method with success similar to that of in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT), in spite of a severe male factor. The study also indicated transfer route and embryo quality (viability) to be very important factors in the success of ICS!. The tubal transfer route was shown to be a significant contributor to the pregnancy success (compared to uterine transfer) as was the transfer of embryos that showed early division to the 2-cell stage, 26 hours post injection. The transfer of early dividing embryos into the fallopian tube resulted in a pregnancy rate of almost 40%, a result similar to that of GIFT with a mild male factor. The role of the oocyte in fertilization and pregnancy success was also revealed indirectly by the introduction of ICS!. Visual observation of denuded oocytes was possible and many morphological features, normal and abnormal, can be observed. Immature oocytes can also be identified and it was shown that they could be successfully matured in vitro before injection. In this study transmission electron microscopy (TEM) was used to study abnormalities in oocyte morphology. The standard method was adapted and modified for single cell TEM. The abnormalities observed included lysosomal and non-lysosomal degeneration (yellowish or darkly coloured oocytes), degeneration and vacuole formation (vacuolated oocytes), large secondary lysosomes filled with multiple small lipid droplets - lipofuscin body (refractile body) and a fragmented oocyte. It was also possible to study at ultrastructural level, possible reasons for fertilization failure in ICS!. Different stages of oocyte activation failure, cytoplasmic immaturity, sperm cell extrusion, abnormal sperm cell decondensation, female spindle abnormalities and technique related factors were observed. TEM was also successfully implemented to elucidate the reason for infertility in a patient with a longstanding, unexplained history of infertility. TEM evaluation of two of the patient's unfertilized oocytes revealed a spindle abnormality with contributing cytoskeletal anomalies at ultrastructural level. The modified TEM technique offers a valuable tool to study this small, but important group of patients with unexplained infertility. ThisTEM study opened up a new, valuable and interesting avenue of research with both diagnostic and prognostic value for patients with unexplained infertility. ICSI is therefore a valuable method in the treatment of especially male factor infertility. It is the most advanced fertilization technique developed in the last decade in this field. Not only can almost all male factor patients be treated, but unexplained female infertility can also be exposed, studied and hopefully in future also be treated with micromanipulation methods.