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Biomedical subjects

G M Warnes

Publications and source records attributed to G M Warnes.

At least 19 recordsLinked to original sources
PubMed1994

Sex determination of preimplantation embryos by human testis-determining-gene amplification.

When there is a risk of inherited disease, preimplantation diagnosis gives couples an opportunity to avoid having a child with the disease. Sex determination can be used to exclude the likelihood of a sex-linked disorder. Accuracy of the diagnosis is important. We have tested the reliability of sex determination based on the recognition of a testis-determining gene (SRY) sequence. DNA from the blood of 120 men and women and from 38 single lymphocytes was amplified by polymerase chain reaction (PCR) with the SRY and control (ZP3) gene primers. All results confirmed the correct sex of origin (100%). The test was then used to determine the sex of 21 single embryo cells biopsied from 21 (4-8 cell) human polyspermic embryos. 2 embryo cells recognised at biopsy to have degenerated produced negative results. The other 19 single embryo cells showed 100% PCR amplification. 11 (58%) of the embryos were judged to be "male" and 8 (42%) "female". The SRY and ZP3 gene primers selected are highly specific and give accurate results in sex determination and their use provides a new reliable method for routine preimplantation and general prenatal sex determination in man.

Animals↗
PubMed1994

Local experience with zona drilling, zona cutting and sperm microinjection.

Clinical trials were performed between 1987 and 1992 on the use of zona drilling (ZD), zona cutting (ZC) and subzonal sperm microinjection (SZI) for the treatment of severe male infertility. ZD significantly improved the fertilization rate, but embryo morphology was poor and no pregnancies were achieved, so it was abandoned in favour of ZC. The fertilization rate was acceptable in the first trial of ZC but embryo morphology was still poor and no pregnancies were achieved, so a number of protocol changes were instigated. Shrinkage of oocytes in hypertonic sucrose prior to ZC markedly improved embryo quality, whereas transfer of embryos on Day 3 after oocyte retrieval enhanced the pregnancy rate. However, despite these improvements, the overall pregnancy rate in the third ZC trial was still low (16.6% per transfer), so a trial of SZI was initiated in 1992. The overall fertilization rate in 82 SZI cycles was 34.4% and, although the polyspermy rate was high, a clinical pregnancy rate of 30.8% per transfer and an implantation rate of 18.4% per embryo were achieved. These trials demonstrate that SZI is a successful treatment for severe male infertility; under the trial conditions, at least, it was superior to ZD or ZC.

Embryonic and Fetal Development↗
PubMed1994

Successful treatment of severe male factor infertility in 100 consecutive cycles using intracytoplasmic sperm injection.

In this report, we present the results of our first 100 consecutive cycles of intracytoplasmic sperm injection (ICSI). Overall, fertilization occurred in 98% of cycles and embryos were transferred in 94% (2.6 embryos per cycle). About 50% of patients had embryos frozen. The overall fertilization rate was 71%, of which 4% were abnormally fertilized (three pronuclei). A total of 30 clinical pregnancies were established (32% per transfer), resulting in 18 singleton, six twin and one triplet ongoing pregnancies. The implantation rate per embryo was 15%. There were no significant differences in the fertilization or pregnancy rates between patients who had only occasional motile spermatozoa in the ejaculate, semen that was too poor for routine in-vitro fertilization (IVF), or who had failed routine IVF and/or subzonal sperm injection (SUZI). A group of 18 patients were treated with both ICSI and routine IVF on their first cycle because of the high likelihood of failed fertilization due to poor sperm morphology < 20% normal). In this group, ICSI oocytes had a fertilization rate of 76% compared to only 15% for the routine IVF (control) oocytes, and six patients conceived after transfer of ICSI embryos (33%), indicating that ICSI can be used successfully on 50% of the oocytes if fertilization failure is expected. Similarly, patients who had failed to become pregnant with SUZI achieved excellent results after ICSI. There were no significant differences between ICSI and routine IVF in the proportions of grade 1, 2 or 3 embryos on day 3 post-oocyte recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Decrease in luteal gonadotropin concentration in conception cycles after in vitro fertilization/gamete intrafallopian transfer.

The concentrations of the gonadotropins, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured in the luteal phase of the cycle in patients undergoing ovarian hyperstimulation. In nonconception cycles, FSH and LH were increased in the late luteal phase compared with conception cycles in which both gonadotropins were suppressed. Estradiol (E2) and progesterone concentrations increased in pregnancy cycles and may be the sole cause for the decreased gonadotropin concentrations as shown by equivalent concentrations of LH and FSH in both pregnancy and nonpregnancy cycles after matching for E2 concentrations. Subjects who subsequently had twin pregnancy or a spontaneous abortion were compared with those with a successful ongoing singleton conception. There were no significant differences relative to LH and FSH between the three groups, although in twin pregnancy FSH tended to be lower at day 16 from oocyte recovery. It is concluded that suppression of LH and FSH in hyperstimulated pregnancy cycles occurs after the time of the rising human chorionic gonadotropin concentrations in plasma.

Abortion, Spontaneous↗
PubMed1991

Differential effects of gonadotrophin-releasing hormone agonists administered as desensitizing or flare protocols on hormonal function in the luteal phase of hyperstimulated cycles.

The incorporation of gonadotrophin-releasing hormone agonist (GnRHa) in in-vitro fertilization (IVF) stimulation protocols has led to doubt about the quality of the subsequent luteal phase. The effects of two GnRHa stimulation protocols on luteal phase concentrations of oestradiol (E2), progesterone (P), luteinizing hormone (LH) and follicle stimulating hormone (FSH) were compared with the standard clomiphene stimulation regimen. Subjects receiving clomiphene with human menopausal gonadotrophin (HMG, n = 377) showed essentially similar luteal phase P concentrations to those receiving leuprolide acetate/HMG as a desensitization protocol. Subjects receiving concomitant leuprolide and HMG from day 2 to utilize the flare effect of the GnRHa exhibited significantly lower P levels in the luteal phase compared to clomiphene/HMG and leuprolide desensitization protocols despite the addition of HCG support. This occurred despite equivalent E2 concentrations at the time of ovulation and identical numbers of oocytes recovered. LH concentrations in non-conception cycles were suppressed for at least 14 days in the luteal phase in both GnRHa protocols compared to clomiphene stimulation. Differences were less obvious in cycles where conception occurred suggesting that implantation may proceed more favourably when the luteal endocrinology was optimal. It is concluded that flare methods of GnRHa hyperstimulation are associated with significantly different luteal phases compared with clomiphene or desensitization protocols. It is proposed that the use of the flare type of stimulation may significantly influence the response of the granulosa cells to LH or HCG via gonadotrophin receptors or through altered post-receptor function.

Chorionic Gonadotropin↗
PubMed1991

Experience with zona drilling and zona cutting to improve fertilization rates of human oocytes in vitro.

Zona drilling (ZD) and zona cutting (ZC) were used in an IVF programme to assist fertilization in semen defect patients. Twenty-seven patients consented to ZD where acidified Tyrode's was used to create a hole in the zona pellucida. In 19 patients, ZD increased the fertilization rate to 29% compared with 8% (P less than 0.001) in their routine IVF cycles, and in eight patients precluded from routine IVF, a fertilization rate of 14% was achieved. Twenty-two patients consented to ZC where a slit in the zona is made mechanically. In 12 patients ZC increased the fertilization rate to 31% compared with 14% (P less than 0.01) from previous routine IVF cycles, and in 10 patients precluded from routine IVF, a fertilization rate of 34% was achieved. In 13 cycles, 68 uncut control oocytes were inseminated. In five cycles both control and ZC oocytes were fertilized (n.s.d.). In eight cycles no control oocytes were fertilized compared with 27% of ZC oocytes. The polyspermy rate was 4.6%. Twenty-four per cent of ZD and 12% of ZC (P less than 0.01) oocytes and embryos were degenerate after 42 h. Both ZD and ZC can increase the fertilization rate of sub-optimal semen, however, in our hands neither technique produced a pregnancy.

Cell Survival↗
PubMed1991

The leuprolide flare regime for in-vitro fertilization/gamete intra-fallopian transfer and embryo cryopreservation.

Gonadotrophin releasing hormone agonists (GnRHa) are now well established as adjuvant agents for in-vitro fertilization (IVF)/gamete intra-Fallopian transfer (GIFT) but several different modes of usage have been proposed. Our experience with 328 cycles of leuprolide used in a flare regime is reviewed. An endocrinologically proven flare effect was associated with a reduction of human menopausal gonadotrophin (HMG) usage (10 versus 16 ampoules) and a lower cycle cancellation/conversion rate (7.4 versus 11.3%). Overall, satisfactory rates of oocyte recovery (93%, mean number of oocytes 7.0), clinical pregnancy (24.4% per oocyte recovery) and pregnancy from frozen/thawed embryo transfers (14%) were achieved. The flare protocol appears to be a satisfactory choice for the majority of subjects but careful monitoring is required to avoid the potential for ovarian hyperstimulation.

Cryopreservation↗
PubMed1991

A prospective trial of intrauterine insemination of motile spermatozoa versus timed intercourse.

STUDY OBJECTIVE: The efficacy of intrauterine insemination (IUI) of selected motile sperm. DESIGN: Prospective randomized sequential alternating cycle trial comparing IUI with luteinizing hormone (LH)-timed intercourse. SETTING: Clinical infertility service. PATIENTS: Couples selected included unexplained infertility (n = 73), cervical mucus hostility (n = 24), moderate semen defect (n = 110), and severe semen defect (n = 78). Two hundred eighty-five couples undertook 600 IUI cycles and 505 LH-timed intercourse. RESULTS: Overall, IUI was slightly more effective than LH-timed intercourse with a pregnancy rate of 6.2% versus 3.4% per cycle. When individual categories were considered only, IUI for severe semen defect was significantly better (5.6% versus 1.3%, P less than 0.05). The first IUI cycle was more effective when compared with both subsequent IUI cycles and the initial LH-timed cycle. Overall, 74% (27/37) of IUI pregnancies occurred in the first cycle. CONCLUSIONS: Compared with LH-timed intercourse, IUI provided little or no improved expectation of pregnancy but was beneficial in couples with severe semen defect. The occurrence of pregnancy was limited per cycle and confined essentially to the initial cycle of treatment. Continued IUI is considered to be unrewarding.

Cervix Mucus↗
PubMed1990

Failure of body mass index or body weight to influence markedly the response to ovarian hyperstimulation in normal cycling women.

A retrospective analysis was performed of 368 normally cycling women treated with a single cycle of a standard ovarian hyperstimulation regime (CC 100 mg days 5 to 9 and hMG 150 IU days 6, 8, and 10) associated with either an IVF or GIFT program. Neither the peak serum E2 level attained nor the number of days of stimulation required bore a relationship to the BMI or the total body weight of these women. Whereas the mean number of oocytes aspirated from women with BMI less than 19.1 was higher (6.4 +/- 3.2) compared with obese women (BMI greater than 27.6, 4.8 +/- 2.6), the rate of fertilization was not different for both BMI extremes. It is concluded that factors other than BMI or total body weight have more important influences on the response to hyperstimulation in normal women.

Body Mass Index↗
PubMed1990

Luteal function associated with single, multiple and ectopic embryo implantation in natural cycles or after ovarian hyperstimulation for in-vitro fertilization/gamete intra-fallopian transfer.

Levels of reproductive steroids and gonadotrophins were analysed retrospectively during the peri-implantation period following non-conceptional and conceptional natural cycles and in cycles associated with ovarian hyperstimulation for in-vitro fertilization or gamete intra-Fallopian transfer. In cycles not associated with conception, the luteal phase of hyperstimulated cycles (n = 100) was characterized by higher serum progesterone and oestradiol levels (P less than 0.01) and with an earlier decline in steroids than in natural cycles (n = 21). On day 11 (day of oocyte recovery = day 0), the level of progesterone in twin (n = 59) and triplet (n = 13) pregnancies was higher than singleton pregnancies (n = 176) (P less than 0.006, P less than 0.006 respectively) while those destined to abort (n = 66) had lower progesterone levels (P less than 0.01). Ectopic implantation (n = 11) had the lowest progesterone concentrations on day 11 (P less than 0.01) and this may imply a delay in corpus luteum rescue or a later implantation time than intrauterine conception.

Clomiphene↗
PubMed1989

Adjuvant leuprolide in normal, abnormal, and poor responders to controlled ovarian hyperstimulation for in vitro fertilization/gamete intrafallopian transfer.

Fifty patients (normal responders) received either human menopausal gonadotropin (hMG) alone (control group) or leuprolide + hMG (leuprolide group). The use of leuprolide was associated with a reduction of hMG requirements (14.8 versus 17.8 ampules, P = 0.02) and the abolition of spontaneous luteinizing hormone surges (nil versus 3, P = 0.006). The rate of fertilization (87% versus 65%, P = 0.003) was higher in the leuprolide group. Pituitary and ovarian suppression was effected for 16 subjects who had previously shown a poor follicular response and a further 19 subjects who had previously responded abnormally. The poor responders required more hMG (43.9 versus 27.1 ampules, P less than 0.001), achieved a lower estradiol maximum (5.1 versus 12.1 nmol/l, P less than 0.001), and had fewer oocytes recovered (4.1 versus 11.5, P less than 0.001), than the abnormal responders.

Drug Therapy, Combination↗
PubMed1989

Increase in digyny explains polyploidy after in-vitro fertilization of frozen-thawed mouse oocytes.

Fewer frozen-thawed mouse oocytes cleaved to the 2-cell stage compared to fresh control oocytes fertilized in vitro (46% vs 79%). The reduced rate of 2-cell formation was only partly explained by a decreased rate of fertilization (63% vs 85%). However, subsequent development to expanded blastocysts was not different (75% vs 78%). An increased frequency of second polar body retention by fertilized frozen-thawed oocytes compared with controls (11.8% vs 1.3%) was shown to be largely responsible for the higher incidence of polyploidy (16.3% vs 3.7%). The frequency of polyspermic fertilization was not different in the two groups (3.9% vs 2.3%).

Animals↗
PubMed1988

The effect of transferring pronuclear embryos on pregnancy outcome after in vitro fertilization.

In a prospective clinical trial the pregnancy rate in patients matched for infertility status, degree of hyperstimulation, and number of oocytes recovered was unaffected by whether embryos were transferred while still pronuclear (day 1) or after they had undergone cleavage (day 2). The pregnancy rates per transfer were 27% and 22%, respectively, for the two transfer times. Unlike results of a previous study, no difference was detected in the outcome of pregnancies from the two groups.

Cell Division↗
PubMed1988

Comparison of zona cutting and zona drilling as techniques for assisted fertilization in the mouse.

Zona cutting and zona drilling of the mouse oocyte significantly increased the fertilization rate (3.8-90%) at low sperm concentrations (less than 200,000/ml) compared with zona-intact controls (0-45%). More oocytes were fertilized after zona drilling. Zona cutting was associated with a low loss of oocytes (less than 1%), no increase in polyspermy and normal development in vitro and in vivo after fertilization. There was a 4% oocyte loss rate after zona drilling, mostly due to extrusion of the oocyte from the zona during the procedure. Hatching of blastocysts occurred about 12 h earlier for zona-drilled than for zona-cut and zona-intact control oocytes. Zona drilling was associated with a higher, but not statistically significant, rate of polyspermy at all sperm concentrations tested. The proportion of zygotes developing to the blastocyst stage was not different between the techniques (zona cut, 77%; zona drilled, 66%; control, 71%). Similarly, no difference was found in the percentage of embryos implanting after blastocyst transfer to the uterine horns of pseudopregnant female mice (zona cut, 67%; zona drilled, 68%; control, 77%). Transmission electron microscopy demonstrated the induced defects in the zona with no damage to the oocyte or oolemma. Parthenogenetic activation was not seen after either of the micromanipulative techniques. Both techniques have promise for application to the human.

Animals↗
PubMed1986

Pregnancy-related chemotactic activity of human follicular fluid.

We measured chemotactic activity in 238 follicular fluids (FF) aspirated from 45 women who had undergone ovarian stimulation with a combination of clomiphene citrate and human menopausal gonadotropin for oocyte retrieval, in vitro fertilization, and embryo transfer. Fifteen of the treatment cycles resulted in pregnancy. The mean chemotactic activity, measured as the distance in microns granulocytic leukocytes migrated through a 3.0-micron membrane, was significantly higher in FF from conceptual cycles, compared with nonconceptual cycles. Serum chemotactic activity was significantly lower in conceptual cycles, compared with nonconceptual cycles. A chemotactic gradient appears to exist between the peripheral circulation and the ovarian follicle. The gradient favors the follicle in conceptual cycles, as indicated by the chemotactic quotient (the ratio of chemotactic activity of FF to serum). In conceptual cycles the chemotactic quotient was 1.7 +/- 0.17, compared with 0.7 +/- 0.03 for nonconceptual cycles. The presence of leukocyte chemotactic factor in FF appears to discriminate prospectively with a 90% degree of confidence between conceptual and nonconceptual in vitro fertilization and embryo transfer cycles.

Androstenedione↗