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Biomedical subjects

I Craft

Publications and source records attributed to I Craft.

At least 37 records · Page 2Linked to original sources
PubMed1995

The time of appearance and disappearance of fetal DNA from the maternal circulation.

A single copy Y-chromosome DNA sequence was amplified using the polymerase chain reaction (PCR) from the peripheral blood of 30 women who had achieved a pregnancy through an in vitro fertilization (IVF) programme. The time of conception was known precisely and was confirmed by serial ultrasound scans. Conceptions were dated as the number of weeks after fertilization plus 2, to give a time equivalent to the obstetric menstrual dating of the pregnancy (LMP). Y-chromosome-specific DNA was detected in all pregnancies with a male fetus (18/30). The earliest detection was at 4 weeks and 5 days, and the latest at 7 weeks and 1 day. Y-chromosome-specific sequences were no longer detected in any of the male pregnancies 8 weeks after delivery. No Y-chromosome sequences were detected in any of the pregnancies where only female babies were delivered. This demonstrates that fetal DNA appears in the maternal circulation early in the first trimester, that it can be identified in all pregnancies tested by 7 weeks, that it continues to be present throughout pregnancy, and that it has been cleared from the maternal circulation 2 months after parturition. Early non-invasive prenatal diagnosis for aneuploidies and inherited disorders will be possible in all pregnancies if fetal cells can be isolated free from maternal contamination (or identified accurately in the presence of maternal cells) without problems of contamination from previous pregnancies.

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PubMed1995

Late intracytoplasmic sperm injection in unexpected failed fertilization in vitro: diagnostic or therapeutic?

OBJECTIVE: To evaluate fertilization potential of 24-hour-old unfertilized oocytes using intracytoplasmic sperm injection and the pregnancy potential of resultant embryos. DESIGN: Prospective observational study. SETTING: Private infertility clinic, London, United Kingdom. PATIENTS: Fifteen patients with a history of infertility who underwent treatment with IVF and showed failure of fertilization on the day after oocyte retrieval. INTERVENTION: Assisted fertilization with intracytoplasmic sperm injection was carried out at 24 hours after oocyte retrieval. RESULTS: A total of 121 metaphase II oocytes were subjected to intracytoplasmic sperm injection. Of these, 9 were damaged (7%), 2 were polyploidic (2%), and 58 showed normal fertilization (48%). Of the latter, 47 cleaved normally (81%). Forty embryos were transferred and three were cryopreserved. One patient conceived (7%) but in this case only one of three embryos transferred was from intracytoplasmic sperm injection. CONCLUSION: Late (24 hours) intracytoplasmic sperm injection can give good fertilization and cleavage rates but the potential of the generated embryos to achieve pregnancy seems to be low.

Adult↗
PubMed1995

Percutaneous epididymal sperm aspiration and intracytoplasmic sperm injection in the management of infertility due to obstructive azoospermia.

OBJECTIVE: To evaluate the recovery rate of spermatozoa from the epididymis using a percutaneous aspiration technique and to examine the fertilization rate after intracytoplasmic sperm injection. DESIGN: Prospective observational study. SETTING: Private infertility clinic, London. SUBJECTS: Twenty patients with obstructive azoospermia who each had an attempt at IVF. The sperm used for intracytoplasmic sperm injection was retrieved by percutaneous epididymal sperm aspiration in 16 patients. In one patient, microepididymal sperm aspiration was performed in addition because the quality of the sperm obtained by percutaneous epididymal sperm aspiration was not considered suitable for microinjection. In the remaining three patients, neither percutaneous epididymal sperm aspiration nor microepididymal sperm aspiration resulted in the recovery of sperm, which was obtained by testicular biopsy in one of them. INTERVENTION: Assisted fertilization with intracytoplasmic sperm injection. MAIN OUTCOME MEASURES: Normal fertilization and pregnancy rates. RESULTS: A total of 179 eggs were collected and 157 subsequently were microinjected. Normal fertilization occurred in 22 oocytes (14%) and the total number of embryos cleaved was 30. Twelve patients underwent ET in which three conceived (pregnancy rate 25% per transfer). The implantation rate was 10% and failed fertilization occurred in four cycles. CONCLUSION: Percutaneous epididymal sperm aspiration can be used successfully to recover sperm in men with obstructive azoospermia for use in assisted fertilization IVF cycles. The technique is simple, effective, and less traumatic compared with an open microsurgical operation.

Adult↗
PubMed1994

Experience with subzonal insemination (SUZI) and intracytoplasmic sperm injection (ICSI) on unfertilized aged human oocytes.

OBJECTIVE: The aim of this study was to assess the fertilizability of unfertilized aged human oocytes from failed in vitro fertilization (IVF) cycles using SUZI and ICSI. METHODS: A total of 363 oocytes which showed no fertilization after conventional IVF was subjected to assisted fertilization using SUZI or ICSI. The microinjected oocytes which were derived from 72 patients undergoing their first IVF treatment had an intact polar body and no signs of degeneration. SUZI was carried out in 265 oocytes and ICSI in the remaining 98. RESULTS: Significantly more oocytes were damaged after ICSI (9 vs 0.3%, P < 0.01). Normal fertilization rates were higher at 24 hr in both groups and occurred more frequently after ICSI, although the difference did not reach statistical significance. Abnormal fertilization occurred significantly more often after SUZI at 48 hr (P < 0.005), but not at 24 hr. Cleavage rates were significantly higher after ICSI (94.4 vs 57.1%, P < 0.025) at 24 hr, but this was not observed at 48 hr, although the ICSI group still showed better cleavage rates (33.3 vs 19.1%). There was no difference in embryo quality in either group. CONCLUSIONS: Our results indicate that micromanipulation rather than reinsemination should be carried out on unfertilized human oocytes from failed IVF attempts. Both techniques can be used to achieve fertilization which occurs more often after ICSI. However, the trauma from the former technique on the microinjected oocytes may impair the potential of the generated embryos to achieve pregnancy compared to SUZI. Prospective randomized trials are necessary to address the problem.

Adult↗
PubMed1994

Pregnancies after assisted fertilization for "extreme" male factor: report on three cases.

Three cases of extreme male factor infertility, not acceptable for conventional IVF, are presented. In the first case, only 30 sluggishly motile spermatozoa were obtained in two ejaculates but treatment with SUZI resulted in a viable singleton pregnancy. In the second case, a combination of microepididymal sperm aspiration, for vasal obstruction after failure of reversal, with intracytoplasmic sperm injection resulted in a viable singleton pregnancy. In the third case, the husband had a vasal reservoir for distal vasal blockage. Sperm from the reservoir with extremely low motility and high antisperm antibody were microinjected by intracytoplasmic sperm injection and this resulted in a triplet pregnancy.

Adult↗