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![The performance of human sperm in an assisted conception programme için kapak resmi The performance of human sperm in an assisted conception programme için kapak resmi](/client/assets/d79c3e4af2b6d196/ctx/images/no_image.png)
The performance of human sperm in an assisted conception programme
Başlık:
The performance of human sperm in an assisted conception programme
Yazar:
Critchlow, Jacqueline Diane, author.
ISBN:
9780438084780
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (282 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Özet:
The performance of human sperm was examined in three areas of assisted conception technology with a view to maximizing the chance of successful treatment outcome: i) a quality control bioassay using human sperm was developed to identify potentially cytotoxic equipment or materials which may compromise the viability of human gametes and embryos during assisted conception procedures. In comparison with established one-cell and two-cell mouse embryo bioassays, human sperm survival studies proved as effective for detecting major toxic contaminants. Test conditions were optimized to maintain the forward progressive motility of donor sperm and the bioassay was performed over 4 days at room temperature. Comparison between the control and the test samples was used to calculate a sperm survival index. Cytotoxicity was detected in several items containing rubber components and also from unexpected sources eg. embryo transfer catheters. Inter-batch variation of products was also detected following the initial screen. Non-toxic items were therefore substituted, or methods were used to remove toxic substances and monitored with further use of the bioassay. ii) a strategy to fertilize and cryopreserve supernumerary oocytes normally discarded and wasted at GIFT units was implemented using intravaginal culture. For almost half of the couples included in the study (49%,44/89), the fertilizing ability of the sperm in vitro was confirmed and one or more fertilized oocytes were cryostored for future use. In these cycles, 50% (133/267) of oocytes fertilized and the rate of polyspermy, not previously described, was 6%. The use of thawed embryos to date has given a 17% pregnancy rate per embryo transfer. However, failed fertilization following IVC was unexpectedly high and consequently the overall fertilization rate was reduced (30%,133/444). Furthermore, impaired sperm fertilizing ability could not be diagnosed reliably, since the failure of oocytes to fertilize following IVC did not mean a reduced chance of pregnancy following GIFT. The benefits of IVC in delivering fertilized oocytes at a suitable time and in a convenient manner must be balanced against the results of a previous study suggesting transport followed by conventional IVF is likely to improve the fertilization rates achieved. iii) problems associated with the use of a new technique to assist fertilization in men whose sperm had failed to fertilize their partners oocytes in vitro previously were illustrated. The use of PZD followed by insemination of the micromanipulated oocytes with the standard sperm concentration used for conventional IVF (100,000/m1) did not improve the fertilization rate when compared to zona-intact sibling oocytes. The effects of insemination concentration upon sperm entry following PZD were investigated with model systems utilizing frozen-thawed hamster oocytes and aged unfertilized human oocytes inseminated with donor sperm. Clinical application of PZD with 5 times the standard IVF insemination concentration significantly improved the overall (37%) and monospermic fertilization rates (31%) when compared to control oocytes (p<0.005). The use of aged unfertilized donor oocytes following cryostorage and removal of the zone pellucida also demonstrated that these patients had a reduced proportion of sperm able to fuse with the oolemma compared to donor sperm samples.
Notlar:
School code: 1543
Konu Başlığı:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(686910.1) | 686910-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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