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P Serhal

Publications and source records attributed to P Serhal.

At least 19 recordsLinked to original sources
PubMed2006

Comparative genomic hybridization analysis of human oocytes and polar bodies.

BACKGROUND: Classical cytogenetic methods and fluorescent in situ hybridization (FISH) have been employed for the analysis of chromosomal abnormalities in human oocytes. However, these methods are limited by the need to spread the sample on a microscope slide, a process that risks artefactual chromosome loss. Comparative genomic hybridization (CGH) is a DNA-based method that enables the investigation of the entire chromosome complement. We optimized and evaluated a CGH protocol for the chromosomal analysis of first polar bodies (PBs) and oocytes. The protocol was then employed to obtain a detailed picture of meiosis I errors in human oogenesis. METHODS: 107 MII oocyte-PB complexes were examined using whole genome amplification (WGA) and CGH. RESULTS: Data was obtained for 100 complexes, donated from 46 patients of average age 32.5 (range 18-42). 22 complexes from 15 patients were abnormal, giving an aneuploidy rate of 22%. CONCLUSIONS: The results presented in this study more than double the quantity of CGH data from female gametes currently available. Abnormalities caused by whole chromosome non-disjunction, unbalanced chromatid predivision and chromosome breakage were reliably identified using the CGH protocol. Analysis of the data revealed a preferential participation of chromosome X and the smaller autosomes in aneuploidy and provided further evidence for the existence of age-independent factors in female aneuploidy.

Adolescent↗
PubMed2005

Antral follicle count, anti-mullerian hormone and inhibin B: predictors of ovarian response in assisted reproductive technology?

OBJECTIVE: The objective of this study was to evaluate the relationship between anti-mullerian hormone (AMH), inhibin B and antral follicle count (AFC) with ovarian response. DESIGN: Retrospective study. SETTING: Fertility unit. SAMPLE: AFC was recorded, and a serum sample obtained on day 3 from all patients undergoing in vitro fertilisation (IVF). Patients were given 300 IU/L recombinant follicle stimulating hormone (FSH; Gonal F). The following day blood samples were collected. METHODS Serum samples were assayed for FSH, AMH and inhibin B using commercial immunoassay kits and oestradiol using an in house assay. MAIN OUTCOME MEASURES: Response to gonadotrophin stimulation and the number of eggs collected. RESULTS: AFC was negatively correlated to age (r=-0.426, P < 0.001). Delta inhibin B (levels of inhibin B on day 4 minus day 3) had the best association to the number of eggs collected (r= 0.533, P < 0.001) followed by basal AMH (r= 0.51, P < 0.001) and AFC (r= 0.505, P < 0.001). The number of eggs fertilised was significantly associated with basal AMH (r= 0.592, P < 0.001) and inhibin B (r= 0.548, P < 0.001). AMH with a cutoff of 0.2 ng/mL had the best sensitivity (87%) and specificity (64%) in predicting poor response. A cumulative score using basal FSH, basal AMH, delta E2 (levels of oestradiol on day 4 minus day 3), delta inhibin B, AFC and age gives the best predictive statistics to identify poor responders with 87% sensitivity and 80% specificity and a positive likelihood ratio of 4.36. CONCLUSION: Delta inhibin B had the best positive association with the number of eggs collected and basal AMH is the single best predictor of poor response. AFC has a significant association with the number of eggs collected and is predictive of clinical pregnancy. It is evident that a single parameter is of limited value in predicting ovarian response. However, we have demonstrated a cumulative score using all the above markers could be useful in predicting poor response.

Adult↗
PubMed2003

Preimplantation genetic diagnosis of chromosome abnormalities: implications from the outcome for couples with chromosomal rearrangements.

OBJECTIVES: Chromosomal rearrangements can lead to infertility or repeated spontaneous or induced abortions. The use of preimplantation genetic diagnosis (PGD) allows the selected transfer of chromosomally balanced embryos. The aim of this study was to carry out detailed analysis of the outcome of 11 PGD cycles for 8 patients carrying various chromosomal rearrangements. METHODS: Patients underwent routine in vitro fertilisation with biopsy of embryos on day 3. Specific fluorescent in situ hybridisation protocols were developed for each couple. Embryo transfer was possible in all 11 cycles. RESULTS: The outcome was four pregnancies, leading to three live births and one biochemical pregnancy. Post-zygotic mosaicism was detected in 75% of untransferred embryos, the majority of which were chaotic. Detailed follow-up and analysis provided evidence for the co-existence of chromosomally balanced and abnormal cells in six embryos. The mechanisms involved included chromosome breakage and loss of material. CONCLUSIONS: Biopsy and analysis of two blastomeres, where possible, reduced the risk of misdiagnosis in cases of balanced/aneuploid mosaics. The three live births achieved for the eight couples treated in this series, despite the poor history in almost all cases, is further proof that a policy of biopsying two cells from embryos consisting of six or more cells and a single cell from four- or five-cell embryos is compatible with a positive outcome.

Abortion, Spontaneous↗
PubMed2002

First application of preimplantation genetic diagnosis to neurofibromatosis type 2 (NF2).

Neurofibromatosis type 2 (NF2) is a dominantly inherited cancer predisposition syndrome that is caused bymutations in the NF2 gene. We report here the first clinical preimplantation genetic diagnosis (PGD) forNF2. A protocol was developed to simultaneously amplify the mutation and a single nucleotide polymorphism (SNP) located within the gene. The mutation and polymorphism were analysed by simultaneous fluorescent single-strand conformation polymorphism (SSCP) on an automated DNA sequencer. The mutation, carried by the male partner, was a single base pair substitution affecting a splice site in intron 4 of the gene. The female partner was infertile due to polycystic ovary syndrome and would require IVF to conceive. The couple was found to be informative at a linked intragenic SNP situated in the 5' untranslated region of the gene. The SNP was included in the assay to reduce the risk of misdiagnosis due to allele dropout (ADO). The couple underwent three cycles of treatment during which a total of 43 blastomeres were biopsied from 31 embryos. Amplification at both loci was obtained in 35 cells (81%). A total of five embryos were transferred, two in the first cycle, two in the second and one in the third. No pregnancy ensued. The results of the diagnoses indicated that, in this couple, the inheritance of the mutation may be non-Mendelian. Out of a total of 32 embryos tested only four were found not to carry the mutation. The reasons for this apparent skew remain unknown.

Adult↗
PubMed2002

Pregnancy following preimplantation genetic diagnosis for Crouzon syndrome.

Crouzon syndrome is a dominantly inherited craniosynostosis syndrome which is caused by mutations in the fibroblast growth factor receptor 2 gene (FGFR2). However, a specific point mutation in the FGFR3 gene has also been shown to result in Crouzon syndrome associated with acanthosis nigricans. We report here the first method for preimplantation genetic diagnosis (PGD) of Crouzon syndrome based on multiplex PCR amplification followed by the direct detection of the causative mutation by single-stranded conformational polymorphism (SSCP) analysis. A highly polymorphic short tandem repeat (STR) locus was simultaneously analysed as a control against some forms of contamination. The mutation, carried by the female partner, was a de-novo substitution at codon 338 of the FGFR2 gene. The couple were found to be informative at the D21S11 STR locus. Two clinical PGD cycles were performed, resulting in the biopsy of 36 blastomeres, 25 of which showed amplification at the FGFR2 locus. All of the cells showed expected genotypes at the D21S11 locus with only one incidence of allele drop-out. A total of five embryos were transferred, two in the first cycle and three in the second, resulting in a singleton pregnancy.

Adult↗
PubMed2001

Simultaneous evaluation of basal FSH and oestradiol response to GnRH analogue (F-G-test) allows effective drug regimen selection for IVF.

To determine whether preliminary assessment of ovarian reserve by simultaneous evaluation of basal follicle-stimulating hormone (FSH) and oestradiol response to gonadotrophin releasing hormone (GnRH) analogue (F-G-test) can be used to tailor individually the drug regimen for ovarian stimulation, the in-vitro fertilization (IVF) results of 238 patients were retrospectively analysed. Sixty-two women with abnormal response to the test (DeltaE2 <180 pmol/l and/or FSH >9.5 mIU/ml) had commenced buserelin nasal spray in the mid-luteal phase and discontinued it on cycle day 1. Ovarian stimulation was started on cycle day 3 with 375 IU/day of gonadotrophin. Fifty-three patients completed the treatment cycle (group A). A total of 176 women with normal response to the test (DeltaE2 >180 pmol/l and FSH <9.5 mIU/ml) had continued the GnRH analogue throughout the stimulation cycle and a starting dose of 225 IU/day of gonadotrophin was used from cycle day 3. A total of 158 patients completed the treatment cycle (group B). Group A had significantly higher age (34.9 +/- 4.2 versus 33.2 +/- 4.2) (P < 0.05) and basal FSH (9.2 +/- 3.8 versus 7.0 +/- 2.2) (P < 0.05) and required a higher total dose of gonadotrophin. The numbers of oocytes retrieved and embryos transferred were significantly lower. However, fertilization, clinical pregnancies, and implantation rates were similar in both groups. It was concluded that simultaneous evaluation of basal FSH and oestradiol response to GnRH analogue can be useful in identifying subcategories of women with reduced ovarian reserve who may benefit from reduced GnRH analogue administration and a higher starting dose of gonadotrophin.

Adult↗
PubMed2000

FISH analysis on day 5 post-insemination of human arrested and blastocyst stage embryos.

Preimplantation genetic diagnosis (PGD) is usually performed on cleavage stage embryos on day 3 post-insemination. Fluorescent in situ hybridization (FISH) has revealed four groups of chromosome patterns in embryos at this stage: uniformly normal, uniformly abnormal, mosaic and chaotic. Recently, some in vitro fertilization (IVF) clinics have started to perform blastocyst stage transfer. In blastocysts, conventional karyotyping has shown that all four groups of chromosome patterns are observed. In the present study, embryos were cultured to day 5 and were subject to a two-round multicolour FISH procedure for chromosome analysis to ensure almost every nucleus was examined. Probes for chromosomes X, Y and 18 were used in the first round and those for chromosomes 13 and 21 in the second round. Twenty arrested embryos (274 cells) and 19 blastocyst stage embryos (1272 cells) were analysed. Four arrested embryos and two blastocysts were uniformly diploid. The remaining 33 embryos were mosaic, including 17 blastocysts. Most of the blastocysts had a high proportion of diploid cells while in the arrested embryos, this proportion varied widely. For PGD, this high prevalence of mosaicism persisting to the blastocyst stage may pose problems similar to mosaicism in cleavage stage embryos.

Adult↗
PubMed2000

Basal 17beta-estradiol did not correlate with ovarian response and in vitro fertilization treatment outcome.

OBJECTIVE: To verify the correlation of basal 17beta-E(2) with ovarian response to stimulation and outcome of in vitro fertilization (IVF). DESIGN: Retrospective observational study. SETTING: The Assisted Conception Unit, University College London Hospitals. PATIENT(S): Three hundred five women undergoing IVF and IVF with intracytoplasmic sperm injection. INTERVENTION(S): Basal follicle-stimulating hormone (FSH) and 17beta-E(2) were assessed. The cutoff level for day 2 E(2) established was 250 pmol/L. Each patient was noted for below (group A) or above (group B) the cutoff point according to her basal E(2) level. MAIN OUTCOME MEASURE(S): Basal E(2), age, duration of infertility, cycle day 2 FSH, number of ampules of gonadotropin used, number of days of stimulation, number of retrieved oocytes, fertilization rate, number of embryos transferred, number of cycles with embryo freezing, cancellation rate, clinical pregnancy rate, and implantation rate were compared between the two groups. RESULT(S): No differences were found between group A and group B in the number of oocytes retrieved (8.8 +/- 4.2 vs. 9.3 +/- 4.8), embryos transferred (2.5 +/- 0.8 vs. 2.7 +/- 0.7), cancellation (9.1% vs. 6.9%), pregnancy (24.8% vs. 30%), and implantation rate (12.3% vs. 15.6%). Correlation coefficient and coefficient of determination showed no significant correlation between basal E(2) and the number of oocytes retrieved, age, and basal FSH. CONCLUSION(S): In our study population, basal E(2) was not a sensitive predictor of ovarian response to stimulation and did not correlate with IVF outcome.

Adult↗
PubMed1998

Simultaneous evaluation of basal follicle-stimulating hormone and 17 beta-estradiol response to gonadotropin-releasing hormone analogue stimulation: an improved predictor of ovarian reserve.

OBJECTIVE: To compare different predictors of ovarian reserve. DESIGN: Prospective study. SETTING: The Assisted Conception Unit, University College London Hospitals. PATIENT(S): One hundred seventy-seven patients undergoing IVF treatment. INTERVENTION(S): Blood samples were collected on cycle day 2 to determine basal levels of FSH and 17beta-E2 and the FSH/LH ratio, and on cycle days 3 and 4 to assess the increase in FSH (deltaFSH) and 17beta-E2 (deltaE2) after the commencement of GnRH analogue (GnRH-a) stimulation. Ultrasound scans were performed during ovarian stimulation to assess the number of follicles. MAIN OUTCOME MEASURE(S): Day 2 FSH and 17beta-E2 levels, the FSH/LH ratio, and the deltaFSH and deltaE2 after the commencement of GnRH-a stimulation were correlated with the number of follicles obtained after ovarian stimulation. RESULT(S): All the possible predictors considered, except for the day 2 E2 level and the deltaFSH, correlated significantly with the ovarian response. The best single correlation was between the number of follicles and the deltaE2 (GnRH-a test). When the FSH level was evaluated simultaneously, the correlation was strengthened, resulting in a better negative predictive value. CONCLUSION(S): Simultaneous evaluation of basal levels of FSH and of the response of E2 to GnRH-a stimulation seems to be the best marker of ovarian reserve and a sensitive predictor of response to ovarian stimulation in patients undergoing IVF treatment.

Adult↗
PubMed1998

A familial case of X chromosome deletion ascertained by cytogenetic screening of women with premature ovarian failure.

The association between X chromosome deletions and premature ovarian failure is well established. Previous anecdotal reports however, have not documented the prevalence of X deletions in women with premature ovarian failure. We therefore performed cytogenetic analyses on 79 women with primary or secondary amenorrhoea to assess the utility of screening for a genetic marker for familial premature ovarian failure. A normal karyotype was found in 77 women. One woman with primary amenorrhoea had an XY karyotype and a woman with secondary amenorrhoea had a deletion at Xq 26.1. This second case had a family history of premature ovarian failure, and her mother who underwent premature ovarian failure at 28 years shared this deletion. The early diagnosis of familial X deletions causing premature ovarian failure allowed for the prediction of impending menopause and the implementation of manoeuvres to advance conception. Although cytogenetic aberrations are rare in secondary amenorrhoea, the ability to predict premature ovarian failure can be vital.

Adult↗
PubMed1997

XIST expression in human oocytes and preimplantation embryos.

During mouse preimplantation development, the exclusive expression of the Xist gene from the paternally inherited allele is thought to play a role in the inactivation of the paternally inherited X chromosome in the extra-embryonic cell lineages of the developing female embryo. Recently, inactivation of the paternally inherited X chromosome has also been shown to occur in the extraembryonic cell lineages of the human female conceptus. In this paper, we determine whether the pattern of XIST expression in human preimplantation embryos is similarly correlated with paternal X inactivation. We developed procedures sensitive to the single cell, for the simultaneous analysis of XIST and HPRT expression and of sexing, initially using human fibroblast cells. Application of these procedures to human cleavage-stage embryos derived by in vitro fertilization revealed a pattern of XIST expression different from that in the mouse. Transcripts of the XIST gene were detected as early as the 1-cell zygote and, with increasing efficiency, through to the 8-cell stage of preimplantation development. In addition, transcripts of XIST were detected in both male (hence from the maternally inherited allele) and female preimplantation embryos. This pattern of expression is not consistent with a role for the early expression of the XIST gene in the choice of paternal X inactivation in the extraembryonic cell lineages of the developing human embryo.

Animals↗
PubMed1996

Twin pregnancy following embryo transfer on day 7 of the luteal phase in an oocyte donation programme.

We report a case of a 42 year old female patient with hypergonadotrophic hypogonadism requiring oocyte donation. Spontaneous ovulation occurred during a hormonal replacement treatment cycle and three embryos were transferred 7 days after documented ovulation. This resulted in a viable twin pregnancy. The twins were genetically distinct from the mother. To the best of our knowledge this is the first reported case of a successful transfer of embryos on day 7 of the luteal phase leading to a viable pregnancy in an oocyte donation programme.

Adult↗
PubMed1995

Expression of the myotonin protein kinase gene in preimplantation human embryos.

We have examined the expression of the myotonin protein kinase gene (MPK) in individual human preimplantation embryos. An allele-specific, reverse transcriptase polymerase chain reaction assay was developed to the required sensitivity using human buccal cells. Human cleavage stage embryos, derived by in vitro fertilisation, were assayed for MPK transcription directly, or after biopsy of a single blastomere used to determine the genotype of the embryo. The maternal and paternal genotypes were determined from cumulus cells and sperm, respectively. MPK gene transcripts were detected in embryos at the 1-cell--4-cell stage of development. Detection of transcripts from the paternally-inherited allele confirmed onset of embryonic MPK gene expression at this very early preimplantation stage.

Alleles↗
PubMed1995

Gamete intra-Fallopian transfer or in-vitro fertilization after failed ovarian stimulation and intrauterine insemination in unexplained infertility?

A prospective randomized study was designed to compare gamete intra-Fallopian transfer (GIFT) and in-vitro fertilization (IVF) and embryo transfer in the treatment of couples who have failed to conceive after at least three cycles of ovarian stimulation and intrauterine insemination (IUI). A total of 69 couples with primary unexplained infertility of at least 2 years' duration plus at least three failed cycles of ovarian stimulation and IUI were randomly allocated to either GIFT or IVF/embryo transfer. The clinical pregnancy rate was 34% after GIFT treatment and 50% after IVF/embryo transfer. This difference was not statistically significant. The twin rate in the IVF/embryo transfer group was higher than in the GIFT group (53 versus 17%, P = 0.005). We conclude that patients with unexplained infertility and failed ovarian stimulation and IUI can still achieve encouraging pregnancy rates with IVF/embryo transfer or GIFT. Since IVF/embryo transfer is the least invasive of the two procedures and may yield diagnostic information, we would favour this therapy; however, the number of embryos transferred should be reduced to two to reduce the risk of twin pregnancy.

Adult↗