Search PubMed⌕ Search

Biomedical subjects

I D Cooke

Publications and source records attributed to I D Cooke.

At least 37 records · Page 2Linked to original sources
PubMed1998

Profile of cytokine mRNA expression in peri-implantation human endometrium.

The human embryo and subsequent fetus is a semi-allograft and immunologically foreign to the mother. Successful embryonic implantation and maintenance of normal pregnancy depends on intricate interactions between the invading embryo, maternal endometrium and maternal immune response. Cytokines are pivotal in determining the type of maternal T-helper immune response, which can be divided into T-helper 1 (TH1)-mediated delayed hypersensitivity and T-helper 2 (TH2)-mediated humoral immunity. We examined the pattern of TH1 [interleukin (IL)-2, IL-12 and interferon-gamma] and TH2 (IL-4 and IL-6) cytokine expression in the peri-implantation endometrium of 10 fertile, multiparous women. Endometrial samples were timed to the mid-cycle luteinizing hormone (LH) surge, with collection on days LH+7 to LH+9. Analysis for cytokine mRNA was by mRNA extraction and reverse transcription-polymerase chain reaction. The results show a lack of TH1 and predominant TH2 cytokine expression. We postulate that endometrial cytokines may contribute to the local modulation of maternal adaptive immune response in peri-implantation endometrium, to facilitate successful embryonic implantation and maintenance of pregnancy.

Adult↗
PubMed1998

Phosphoinositide 3-kinase is involved in the induction of the human sperm acrosome reaction downstream of tyrosine phosphorylation.

In somatic cells phosphoinositide 3-kinase (PI 3-kinase) is activated upon interaction with both receptor tyrosine kinases (RTK) and G-proteins resulting in the production of moieties involved in the inositol phospholipid signalling pathway. As G proteins, RTK and the inositol phospholipids have all been implicated in the human sperm acrosome reaction, experiments were carried out to determine whether PI 3-kinase was also involved in this phenomenon. Wortmannin is a selective inhibitor of PI 3-kinase and was shown to significantly inhibit the acrosome reaction induced by both mannose-bovine serum albumin (mannose-BSA) (10, 50 and 100 nM) and a polyclonal antibody raised against an extracellular region of the sperm zona receptor kinase (ZRK, at 100 nM only). Wortmannin did not inhibit the A23187- or progesterone-induced acrosome reaction. These results suggest that PI 3-kinase is involved in the human sperm acrosome reaction. The levels of tyrosine phosphorylation of sperm proteins as detected by Western blotting using antiphosphotyrosine antibodies was not affected by wortmannin in agonist (A23187 and mannose-BSA)-stimulated spermatozoa. This indicated that PI 3-kinase operates downstream of tyrosine phosphorylation in the signal transduction cascade which leads to the human sperm acrosome reaction.

Acrosome Reaction↗
PubMed1998

A combinatorial phage display library for the generation of specific Fab fragments recognizing human spermatozoa and inhibiting fertilizing capacity in vitro.

To select a source of lymphocytes for the generation of an anti-sperm-biased combinatorial phage display library, venous blood was obtained from 34 vasovasostomy (vasectomy reversal) patients approximately 3 mo after surgery. Using a variety of immunoassays, serum was analyzed for antibodies against human spermatozoa, and a patient was selected on the basis of high titer of antibodies that recognized the equatorial region of the sperm head and inhibited sperm fertilizing capacity in vitro. Total RNA isolated from the stored lymphocytes of this individual was reversed transcribed, and gamma1 (Fd) region and kappa chains were amplified by polymerase chain reaction for the successful construction of an antibody phage display library. The library was panned against human spermatozoa to isolate sperm-specific phage that recognized the equatorial region of the sperm head. Three preparations of Fab were tested via the hamster egg penetration test. Each preparation significantly (p < 0. 005) inhibited sperm-egg binding and fusion, with one preparation (designated Fab-G) causing complete inhibition. Sequence analysis of the kappa light gene encoding Fab-G revealed a 93% homology with the light chain of human anti-human immunodeficiency virus gp120 p35 variable region. This technology may have a practical application in characterization of the immune response to spermatozoa and for the design of sperm-based contraceptive vaccines.

Amino Acid Sequence↗
PubMed1998

Factors affecting the outcome of laparoscopic ovarian drilling for polycystic ovarian syndrome in women with anovulatory infertility.

OBJECTIVE: To describe and analyse the factors affecting the pregnancy rate of laparoscopic ovarian drilling for polycystic ovarian syndrome in women with anovulatory infertility. DESIGN: A retrospective study. SETTING: A specialist infertility clinic based at a teaching hospital in England. POPULATION: One hundred and eighteen women, for whom hospital records and follow up data were available, with polycystic ovarian syndrome who underwent laparoscopic ovarian surgery for anovulatory infertility over a five year period, between January 1991 and December 1995. MAIN OUTCOME MEASURES: Ovulation and pregnancy rate. RESULTS: The cumulative conception rate 12 months after the treatment was 54%. Women who conceived following the surgery had a shorter duration of infertility, were treated with diathermy (rather than laser), had higher pre-operative luteinising hormone levels, were younger and were more likely to have ultrasonographic evidence of polycystic ovarian disease. Logistic multiple regression analysis showed that the duration of infertility, modality used in treatment (laser or diathermy) and the pre-operative levels were the main determinants of the outcome. CONCLUSION: Women with polycystic ovarian syndrome respond favourably to laparoscopic ovarian drilling. The success rate in women with infertility duration of less than three years, treated with diathermy, in whom the pre-operative level was more than 10 IU/L reached 79%.

Adult↗
PubMed1997

Response of human spermatozoa to an internal calcium ATPase inhibitor, 2,5-di(tert-butyl) hydroquinone.

This study has investigated the effect of elevating intracellular calcium levels, using an internal calcium ATPase inhibitor, 2,5-di(tert-butyl) hydroquinone (TBQ), on human sperm function. Isolated sperm samples from five fertile donors were incubated in a capacitating media for up to 6 hr. After 0, 3, and 6 hr incubation, sperm were exposed to a range of TBQ concentrations; 100 microM, 10 microM, and 1 microM, for a fixed incubation period of 5 min. Controls were run for each experiment where sperm were incubated for 5 min in the absence of TBQ. Sperm capacitation and the acrosome reaction were monitored prior to and after exposure to TBQ, using the Chlortetracycline assay. In addition, sperm motility was assessed at each time point and after sperm had been exposed to TBQ. The treatment of sperm with TBQ caused a significant increase in the number of capacitated sperm with an optimum response being achieved in the presence of 100 microM TBQ. However, sperm motility was found not to be effected by the addition of TBQ. The results from the present study suggest that elevating intracellular calcium levels in human sperm by short exposure to a high concentration of TBQ can rapidly accelerate the capacitation process. Furthermore, the observation that TBQ did not elicit a change in sperm motility suggests that TBQ may be highly specific in its mode of action by acting within the head region of human sperm.

Acrosome↗
PubMed1997

Elevating intracellular calcium levels in human sperm using an internal calcium ATPase inhibitor, 2,5-di(tert-butyl) hydroquinone (TBQ), initiates capacitation and the acrosome reaction but only in the presence of extracellular calcium.

The aim of this study was to investigate the effect of an internal calcium ATPase inhibitor, TBQ, on human sperm capacitation and the acrosome reaction during incubation in a calcium-depleted media. Sperm were isolated into and incubated for up to 6 hr in media depleted of Ca2+ and two Ca(2+)-containing media controls. At set time intervals, sperm in each media group were treated with 100 microM TBQ for 5 min. Afterwards, sperm were induced to acrosome react using the divalent cation ionophore, A23187, as a measure of sperm fertilizing potential. It was established, using the Chlortetracycline assay, that incubation of sperm in a Ca(2+)-depleted media inhibited or delayed sperm capacitation resulting in fewer spontaneous or A23187-induced acrosome reacted sperm. However, incubation of sperm in a Ca(2+)-depleted media did not appear to inhibit sperm motility. The treatment of sperm with TBQ during their incubation in Ca(2+)-depleted media was found to have very little effect resulting in low numbers of capacitated and acrosome reacted sperm. The results from this study suggest that human sperm have an obligatory requirement for extracellular calcium during capacitation and the acrosome reaction, but may require either very little extracellular Ca2+ to maintain motility or possess internal Ca2+ stores sufficient for their requirements. In addition, TBQ did not increase the number of capacitated and acrosome reacted sperm during incubation in a Ca(2+)-depleted media suggesting that the TBQ-effect of accelerating sperm capacitation is dependent on presence of extracellular Ca2+.

Acrosome↗
PubMed1997

Reversal of sterilisation vs. IVF: a cost-benefit analysis.

A consecutive series of 132 cases of reversal of sterilisation carried out in a teaching hospital in England between 1982 and 1995 was analysed. Follow-up data was obtained on 112 patients. The overall cumulative conception rate was 47% at 12 months and 55% at 24 months. Among the 71 pregnancies there were seven miscarriages (9%) and 11 ectopic pregnancies (15%). Factors affecting the outcome of surgery were examined. The pregnancy rate achieved with microsurgical techniques was significantly higher than the conventional (macrosurgical) techniques (61% v. 40%, P = 0.05). The method of sterilisation also has a significant impact on the outcome; Filshie clips 69%; Fallope ring 46%; Pomeroy technique 31% (P < 0.05). Age, associated infertility factors and the interval between sterilisation and reversal operation did not appear to have a significant impact on the outcome. When compared with IVF, reversal of sterilisation is associated with a higher ectopic rate, lower multiple pregnancy rate and a lower miscarriage rate. We conclude that reversal of sterilisation carries a higher overall success rate than IVF and is more cost effective when the method of sterilisation is by the clip or ring and when the reversal operation is carried out with microsurgical techniques.

Journal Article↗
PubMed1997

Natural cycle in-vitro fertilization in couples with unexplained infertility: impact of various factors on outcome.

This study evaluated outcome in 117 couples with unexplained infertility who underwent 162 attempts at natural cycle in-vitro fertilization (NIVF) between 1991 and 1993. An egg was obtained in 138 cycles and a single embryo was transferred in 89 cycles. There were 16 implantations (four biochemical pregnancies, three clinical abortions and nine live births). The implantation rate per embryo was 16/89 (18.0%), which translated into a live birth rate per egg collection of 9/138 (6.5%). The impact factors that were assessed included oocyte quality, sperm quality, embryo quality and woman's age. The outcome measures used were fertilization/inseminated egg and implantation/replaced embryo. All embryo transfers were of single embryos. We conclude that, in couples with unexplained infertility, outcome following NIVF is affected by both egg and sperm quality and by the age of the woman. Embryo quality was independent of the above factors but was also critical for successful implantation.

Adult↗
PubMed1997

Comparison between stimulated in-vitro fertilization and stimulated intrauterine insemination for the treatment of unexplained and mild male factor infertility.

A prospective trial was undertaken to evaluate the efficacy of stimulated in-vitro fertilization (SIVF) and stimulated intrauterine insemination (SIUI) in couples with unexplained and mild male factor infertility. In all, 80 couples were allocated to treatment with SIVF or SIUI, both treatments following the same protocol [clomiphene citrate and follicle stimulating hormone (FSH) injection], except that higher doses of FSH were used in the SIVF treatment cycles. Initially, 41 couples were allocated to and started treatment with SIVF but eight cases were eventually converted to SIUI because of under-response. Similarly, although 39 couples were initially allocated to SIUI treatment, five of these converted to SIVF because of over-response. The treatment cycles that were converted either to SIUI or to SIVF were not considered as treatment failures but as treatment changes and so were included in the analyses. Of the final 38 SIVF cycles, four were cancelled (dysfunctional response), failed fertilization occurred in five cycles and 29 subjects reached embryo transfer. There were two biochemical pregnancies [positive human chorionic gonadotrophin (HCG) only], two clinical abortions and seven live births. Of the final 42 SIUI cycles, only two were cancelled, insemination being performed in the remaining 40 cases. The result was one clinical abortion, three ectopics and eight live births. The proportion of cycles with positive HCG was identical (28.9% per cycle treated for SIVF and 28.6% for SIUI) and the livebirth rates were also not different (18.4% per cycle treated for SIVF and 19.0% for SIUI). The cost per maternity of SIUI was approximately half that of SIVF (Pounds Sterling 1923 versus Pounds Sterling 4611) and so we conclude that, as SIUI had an efficacy that was not significantly different from SIVF (using similar protocols) but was more cost-effective, it must be considered the more appropriate form of management for the treatment of unexplained and mild male factor infertility. Indeed, it is hard to justify the routine use of IVF, as a first approach, in unexplained infertility.

Adult↗
PubMed1997

Identification of ovarian antibodies by immunofluorescence, enzyme-linked immunosorbent assay or immunoblotting in premature ovarian failure.

The development of new techniques for the detection of ovarian antibodies has challenged early concepts about the rarity of ovarian antibodies in idiopathic premature ovarian failure (POF), but few attempts have been made to compare results between assays. We have sought to define the prevalence of ovarian autoimmunity in a group of 30 idiopathic POF patients compared to a group of 12 patients with POF plus an associated autoimmune disease and a group of 38 controls, using an enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IFL). Ovarian antibodies were detected in 27% of idiopathic POF patients by ELISA (not significantly different compared to POF patients with associated autoimmune disease; P < 0.0003 compared to controls) but only 7% of these patients were positive by IFL. In a further, pre-selected group of individuals, all positive for ovarian antibodies by IFL, 53% had measurable antibodies by ELISA. Some overlap was therefore demonstrated between the two techniques but many POF patients had ovarian antibodies detectable by only one method. Immunoblotting studies revealed that no consistent pattern of binding could be demonstrated for these patients. These results call into question the specificity of ovarian antibodies as a marker for autoimmune POF.

Adult↗
PubMed1997

Is subclinical ovarian failure an autoimmune disease?

Young women with unexplained infertility who exhibit elevated basal serum follicle stimulating hormone (FSH) concentrations (>10 IU/l) have poor outcomes in in-vitro fertilization. A subgroup of these women has regular menses, representing 'subclinical' ovarian failure, which may have an autoimmune basis and could potentially be treated by immunosuppression. To investigate this further, a range of immunological markers was used to assess autoimmune activity in 14 women aged <40 years with elevated FSH compared with 15 infertile women with normal FSH and 10 pre-menopausal, healthy controls. All samples were taken during natural menstrual cycles. Organ-specific antibodies against ovary, endometrium and thyroid, and non-organ-specific antibodies against histones and cardiolipin, were not significantly increased in elevated FSH patients compared with other control groups. Soluble CD23 and soluble intercellular adhesion molecule concentrations were not elevated in the sera of the women tested, and circulating T cell subsets remained unaltered. Significantly, increased concentrations of the complement breakdown product C3a and terminal complement complexes were detected in the elevated FSH group compared with the normal FSH group, although the latter also had significant complement activation compared with laboratory controls. Autoimmunity appears as an infrequent cause of 'subclinical' ovarian failure, but there is evidence of activation of complement in the sera of infertile women.

Adult↗
PubMed1997

Retrograde tubal embryo transfer in natural cycle in-vitro fertilization.

Two modes of embryo transfer, uterine and tubal, were compared following natural cycle in-vitro fertilization (IVF). Only patients with patent Fallopian tubes were included in the study. Tubal embryo transfer was performed by retrograde tubal cannulation without analgesia on an outpatient basis. Tubal transfer conferred no benefit compared with uterine transfer in male factor infertility with positive fertilization (pregnancy rates of 15.8% in both groups). Although tubal embryo transfer in the patients with unexplained infertility improved the pregnancy rates from 7.8% in uterine transfer (5/64) to 17.6% in the tubal transfer group (13/74), this improvement was not statistically significant.

Adult↗
PubMed1997

Impact of the learning curve on term delivery rates following laparoscopic salpingostomy for infertility associated with distal tubal occlusive disease.

The objective of this study was to determine the impact of the learning curve of one surgeon on the term delivery rate following laparoscopic salpingostomy for tubal infertility. This was a retrospective audit of ongoing clinical practice, undertaken in two tertiary level infertility programmes. Subjects in this study were women undergoing surgery for total occlusion of the distal Fallopian tube. The main outcome measure was cumulative term delivery rates. On stepwise life-table analysis the length of infertility, primary and secondary infertility, tubal diameter and whether surgery was performed in the first or second half of the series were significantly associated with outcome. These data suggest that there is a learning curve in obtaining skills to perform laparoscopic salpingostomy, that patient selection may improve with experience, and that selection criteria should be emphasized during didactic teaching and the preceptorship process.

Adult↗
PubMed1997

The effect of a single dose of mifepristone (RU486) on the fine structure of the human endometrium during the early luteal phase.

This study examined the fine structure of the human endometrial glandular epithelium after the administration of a single dose of RU486 (mifepristone), given in the early luteal phase. The drug was administered on days 2, 3, 5 and 6 after the luteinizing hormone peak (LH + 0). Biopsies were performed on days LH + 5, 6, 8 and 9. These were compared with control biopsies taken on corresponding days. Qualitatively, the main cytological effect of the RU486 was on the secretory apparatus and on the polarity of the cell. The formation of the nuclear channel system was also affected by the drug. A two-way analysis of variance on cell and nuclear volume data revealed no significant effect of day of biopsy, condition or interaction. Mitochondrial volume and secretory apparatus volume data revealed a significant effect of day of biopsy and interaction term; mitochondrial volume at LH + 5 was 95.9 +/- 25.3 microm3 (mean +/- SD) for control and 57.7 +/- 31.9 microm3 for RU486-treated epithelium. The volume of the secretory apparatus in the treated group was smaller on days LH + 5 and 6 (14.6 +/- 4.2 microm3, 6.41 +/- microm3) when compared to day-matched control biopsies (35.9 +/- 10.5 microm3, 41.7 +/- 26.4 microm3). RU486 administration in the early luteal phase disrupted the secretory activity of the cells. These findings provide an insight into the cellular mechanisms of progesterone receptor blockade in the peri-implantation period.

Adolescent↗
PubMed1997

The pattern of cytokine mRNA expression in ovarian endometriomata.

Intraovarian cytokines play a pivotal role in the normal growth and development of the ovarian follicle. The purpose of this study was to investigate the pattern of cytokine mRNA expression in ovarian endometriomata. A total of 10 patients with histologically confirmed endometriomata undergoing surgery formed the study group while nine patients undergoing sterilization with no evidence of a cyst in the ovary formed the control group. Biopsies of the ovary were obtained at surgery and stored in liquid nitrogen until processed by reverse transcription-polymerase chain reaction amplification to identify the presence of mRNA for interleukin (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, tumour necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma). IL-6 and IL-10 mRNA were expressed by nine and seven patients respectively in the endometriosis group compared with three and one patients in the control group; this difference was significant (P < 0.05). IL-1 alpha mRNA was expressed by seven of 10 patients with endometriosis but by only one of the control group; this was again significantly different (P < 0.04). Ovarian IL-2 and IL-4 mRNA were not expressed in either group. There was no significant difference in the expression of IL-8, IL-13, IFN-gamma and TNF-alpha mRNA in the two groups. These findings suggest that abnormal local expression of certain cytokines may contribute to the development of endometriomata.

Adult↗
PubMed1996

Measurement of intracellular pH in human spermatozoa by flow cytometry with the benzo[c]xanthene dye SNAFL-1: a novel, single excitation, dual emission, molecular probe.

In numerous animal species the acrosome reaction of spermatozoa has been linked to elevations in intracellular pH (pHi). However, whether or not this is merely a passive consequence of calcium ion influx is not known. Studies into the fluctuations in pHi in sperm cells have been hampered by the lack of a pH-sensitive probe that could be used in conjunction with flow cytometry. In this study, flow cytometric analysis of pHi in human spermatozoa was accomplished by using one of the new benzo[c]xanthene dyes (SNAFL-1). SNAFL-1 was then observed in situ with conventional fluorescent microscopy and was found to be located in the post-acrosomal cytoplasm of the head. It was then used to measure the differences in pHi between acrosome intact populations of spermatozoa, and populations that had been induced to acrosome-react with human follicular fluid or the calcium ionophore A23187 to mimic the calcium influx. It was concluded that the human sperm acrosome reaction is also accompanied by a rise in pHi and the natural agonist-induced rise could not be accounted for by calcium ion influx alone.

Acrosome↗