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Biomedical subjects

C A Kirby

Publications and source records attributed to C A Kirby.

13 recordsLinked to original sources
PubMed1994

Chemotaxis of polymorphonuclear leukocytes towards human pre-ovulatory follicular fluid and serum using a 'sparse-pore' polycarbonate filtration membrane.

The chemotactic responses of polymorphonuclear leukocytes (PMN) towards pre-ovulatory follicular fluid and serum from patients participating in an in vitro fertilization program were tested in a modified Boyden chamber using a 'sparse-pore' polycarbonate filtration membrane method. The chemotactic activities of follicular fluids were generally low, but were significantly higher in conceptual cycles than in non-conceptual cycles. The chemotactic activities of sera were generally high, but were significantly lower in conceptual cycles. The chemotactic activity of few follicular fluids ever exceeded that of serum, regardless of the occurrence of conception. These findings demonstrate for the first time using an appropriate technique, that pre-ovulatory follicular fluids can be chemotactic for PMN, but the relationship between this activity, serum chemotactic activity and successful pregnancy is not clear.

Chemotaxis, Leukocyte↗
PubMed1994

The obstetric outcome of singleton pregnancies following in-vitro fertilization/gamete intra-fallopian transfer.

The present study compares 465 singleton live deliveries from in-vitro fertilization/gamete intra-Fallopian transfer (IVF/GIFT) pregnancies with a large control population to evaluate the incidence of pre-term delivery and small for gestational age (SGA) or very small for gestation age (VSGA) babies resulting from IVF/GIFT pregnancies. Overall the incidence of SGA or VSGA from an IVF/GIFT pregnancy is higher than from the normal obstetric population (SGA odds ratio 1.76, 95% confidence interval (CI): 1.38-2.25 and VSGA odds ratio 1.61, 95% CI: 1.05-2.46) particularly among primiparous women (SGA odds ratio 1.99, 95% CI: 1.25-3.16 and VSGA odds ratio 1.97, 95% CI: 1.49-2.62). After stratifying by the cause of infertility, only women with unexplained infertility had a significantly higher proportion of SGA/VSGA babies. There was a significantly higher incidence of pre-term deliveries among the young primiparae (odds ratio 5.02, 95% CI: 3.09-8.13). Thus the excess risk of delivering a SGA/VSGA baby and pre-term delivery from an IVF/GIFT pregnancy seems to be largely confined to women with unexplained infertility and young primiparae.

Adult↗
PubMed1993

Gamete intra-fallopian transfer: outcome following the elective or non-elective replacement of two, three or four oocytes.

The outcome of 807 gamete intra-Fallopian transfer (GIFT) cycles following the elective or non-elective transfer of two, three or four oocytes has been retrospectively studied. Electively replacing either three or two oocytes did not reduce the clinical or ongoing pregnancy rate when compared with replacing four oocytes. The incidence of high-order multiple gestation (triplet or more) was significantly reduced by replacing fewer oocytes, but the occurrence of twin pregnancy was not altered. Lower pregnancy rates were found when the number of oocytes available for replacement was limited and non-elective replacement was performed. It is suggested, therefore, that a higher number of oocytes available may allow selection of higher quality oocytes for transfer. We conclude that the overall expectation of pregnancy from the GIFT procedure is high (30-40%) and the number of oocytes replaced should be two in order to minimize the risk of high-order multiple pregnancies. It is not clear whether increasing the number of oocytes transferred will benefit subjects who failed to become pregnant previously with GIFT, but limited data suggest that transferring large numbers of oocytes to women > 40 years does not improve the expectation of pregnancy.

Age Factors↗
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

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↗
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↗