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Biomedical subjects

Daniel R Brison

Publications and source records attributed to Daniel R Brison.

14 recordsLinked to original sources
PubMed2006

Ovarian response to gonadotropins after laparoscopic salpingectomy or the division of fallopian tubes for hydrosalpinges.

OBJECTIVE: To compare the effect of prophylactic laparoscopic salpingectomy versus division of the fallopian tubes on ovarian response to gonadotropins in women undergoing IVF. DESIGN: Retrospective study. SETTING: National Health Service-based tertiary referral center for reproductive medicine. PATIENT(S): One hundred sixty-eight women with tubal factor infertility. Sixty-five women with hydrosalpinges had either salpingectomy (n = 40, group A) or proximal tubal division (n = 25, group B), while the remaining women with tubal disease but without hydrosalpinges acted as the control group (n = 103, group C). INTERVENTION(S): Prophylactic laparoscopic salpingectomy or proximal division of the fallopian tubes and ovarian stimulation with gonadotropins for IVF. MAIN OUTCOME MEASURE(S): Day 2 serum FSH levels before surgery and 3 months after surgery but before ovarian stimulation, ovarian response assessed as total dose of hMG administered, serum E2 concentrations on day 3 and day 8 of stimulation and on the day of hCG injection, number of follicles, and number of oocytes retrieved and fertilized. RESULT(S): In group A, baseline FSH levels were significantly raised after surgery compared with before surgery. Postsurgery FSH concentrations were significantly higher in group A compared with group B. The number of follicles (15-20 mm) was significantly lower in group A compared with group B and group C. The serum E2 levels on day 8 of stimulation were lower in group A compared with group B, and on the day of hCG injection it was significantly reduced in group A compared with groups B and C. The number of oocytes retrieved per cycle was significantly lower in group A compared with group B. There were no significant differences in pregnancy rates and miscarriage rates among the three groups. CONCLUSION(S): These findings suggest that prophylactic salpingectomy in women with hydrosalpinx may compromise ovarian response to stimulation without affecting pregnancy rates. A randomized control trial is recommended to determine the most appropriate laparoscopic procedure in the management of hydrosalpinx before IVF.

Adult↗
PubMed2006

Metabolomics: current technologies and future trends.

The ability to sequence whole genomes has taught us that our knowledge with respect to gene function is rather limited with typically 30-40% of open reading frames having no known function. Thus, within the life sciences there is a need for determination of the biological function of these so-called orphan genes, some of which may be molecular targets for therapeutic intervention. The search for specific mRNA, proteins, or metabolites that can serve as diagnostic markers has also increased, as has the fact that these biomarkers may be useful in following and predicting disease progression or response to therapy. Functional analyses have become increasingly popular. They include investigations at the level of gene expression (transcriptomics), protein translation (proteomics) and more recently the metabolite network (metabolomics). This article provides an overview of metabolomics and discusses its complementary role with transcriptomics and proteomics, and within system biology. It highlights how metabolome analyses are conducted and how the highly complex data that are generated are analysed. Non-invasive footprinting analysis is also discussed as this has many applications to in vitro cell systems. Finally, for studying biotic or abiotic stresses on animals, plants or microbes, we believe that metabolomics could very easily be applied to large populations, because this approach tends to be of higher throughput and generally lower cost than transcriptomics and proteomics, whilst also providing indications of which area of metabolism may be affected by external perturbation.

Biomarkers↗
PubMed2006

Cryopreserved-thawed embryo transfer in natural or down-regulated hormonally controlled cycles: a retrospective study.

OBJECTIVE: To assess the implantation, pregnancy, and live birth rates after the transfer of frozen-thawed embryos (FET) in a natural or hormonal control cycle. DESIGN: Retrospective study. SETTING: National Health Service tertiary referral center for reproductive medicine in Manchester, United Kingdom. PATIENT(S): Two comparable groups of women with regular menstrual cycles: Group A (n = 212) had FET in a natural cycle after spontaneous ovulation; group B (n = 205) had FET in a pituitary-desensitized hormonally controlled cycle. INTERVENTION(S): In group B, GnRH agonist was commenced in the midluteal phase of the previous cycle and discontinued 3 days before embryo transfer. Oral estradiol valerate and vaginal progesterone pessary were used to prepare the endometrium. Embryo transfer was carried out 3 days after detection of the endogenous LH surge in group A and on day 3 of progesterone administration in group B. MAIN OUTCOME MEASURE(S): Implantation, pregnancy, and live birth rates per cycle and per embryo transfer (ET). RESULT(S): In the 212 women who had natural-cycle FET, 172 ETs were performed and 247 embryos replaced. The implantation rate was 14.1% (35/247). Twenty clinical pregnancies (20/172, 11.6%) were achieved. In the 205 women who had down-regulated hormone replacement-cycle FET, 173 embryo transfers were performed and 243 embryos replaced. The implantation rate was 13.5% (33/243). Eighteen clinical pregnancies (18/173, 10.2%) were achieved. There were no significant differences between the two groups with regard to the implantation, clinical pregnancy, or live birth rates per cycle or per ET. CONCLUSION(S): These findings suggest that both FET protocols are equally effective in terms of implantation rate and pregnancy outcome in women with regular menstrual cycles.

Administration, Intravaginal↗
PubMed2006

The optimal length of 'coasting protocol' in women at risk of ovarian hyperstimulation syndrome undergoing in vitro fertilization.

Ovarian hyperstimulation syndrome (OHSS) is a serious and potentially life-threatening complication following ovarian stimulation for in vitro fertilization (IVF). Coasting is the practice whereby the gonadotrophins are withheld and the administration of human chorionic gonadotrophin (hCG) is delayed until serum oestradiol (E2) has decreased to what is considered to be a safe level, to prevent the onset of OHSS. This study aimed to assess the length of coasting on the reproductive outcome in women at risk of developing OHSS. Coasting was undertaken when the serum E2 concentrations were > or = 17000 pmol/L but < 21000 pmol/L. Daily E2 measurements were performed and hCG was administered when hormone levels decreased to < 17000 pmol/L. Eighty-one women who had their stimulation cycles coasted were grouped according to the number of coasting days. Severe OHSS occurred in one case, which represented 1.2% of patients who underwent coasting because of an increased risk of developing the syndrome. No difference was found between cycles coasted for 1 - 3 days and cycles coasted for > or = 4 days in terms of oocyte maturity, fertilization and embryo cleavage rates. Women in whom coasting lasted for > or = 4 days had significantly fewer oocytes retrieved (P < 0.05) and decreased implantation rate (P < 0.05) compared to those coasted for 1 - 3 days. Pregnancy rate/embryo transfer and live birth rate did not differ between groups. In conclusion, coasting appears to decrease the risk of OHSS without compromising the IVF cycle pregnancy outcome. Prolonged coasting is, however, associated with reduced implantation rates, perhaps due to the deleterious effects on the endometrium rather than the oocytes.

Chorionic Gonadotropin↗
PubMed2005

Challenges imposed by scientific development in ART.

The primary goal of ART is to produce a healthy baby which will develop into a healthy adult. There are a number of challenges which must be met in order to achieve this goal, with possibly two foremost at the present time. The first is to eliminate multiple pregnancy by transfer of a single embryo, and the second is to understand the risks involved in ART. In recent years spin-out technologies have also developed from ART, first the diagnosis of genetic disease in the embryo, and now the derivation of embryonic stem cell lines with the potential to treat a range of human health disorders. Current and future scientific developments can help achieve all of these aims, but present a number of challenges to the ART community and regulatory bodies.

Female↗
PubMed2004

Expression of 11 members of the BCL-2 family of apoptosis regulatory molecules during human preimplantation embryo development and fragmentation.

Apoptosis during preimplantation development has received much interest because of its potential role in eliminating defective cells. Although development in humans is characterised by a high degree of genetic abnormality, little is known of the regulation of apoptosis in embryos. By PolyA PCR we analysed expression of 11 BCL-2 genes in individual human embryos representative of normal development and in severely fragmented embryos. We demonstrate constitutive expression of BAX in virtually all embryos at all stages of development, and variable expression of BCL2, BCL-XL, BCL-W, MCL-1 BAK, BAD, BOKL, BID, BIK, and BCL-XS. The frequency of expression of pro- and anti-apoptotic BCL-2 members was similar throughout development, except at the two-cell stage where pro-apoptotic genes predominated. Protein expression was confirmed for BCL-2, MCL-1, BCL-X, BAX, BAD, and activated caspase 3. BCL-2 protein was associated with mitochondria but expressed inconsistently in the blastocyst inner cell mass. Consistent differences between morphologically intact and fragmented embryos included the expression of BAK in fragmented but not intact four-cell embryos. Our study addresses the importance of examining single human embryos representative of the viable population for a large number of genes, in order to establish meaningful expression profiles and provide information on overlapping function in a large gene family.

Apoptosis↗
PubMed2004

Focus on ART.

Explore the source record for details and available documents.

Cell Culture Techniques↗
PubMed2003

Amplification of representative cDNA pools from single human oocytes and pronucleate embryos.

In the human embryo, gene expression studies have been hindered by the scarcity of material and the fact that in vitro fertilisation (IVF) embryos available for research are usually of poor quality and are, therefore, not representative of normal development. This has led most authors to study individual human embryos, using conventional RT-PCR strategies, which permit analysis of only a few genes. Variability in the expression of genes between individual embryos is characteristic of these studies. In this study, a global RT-PCR strategy has been used, allowing the analysis of an almost infinite number of genes from a single embryo. We have used oocytes, which failed to fertilise and representative pronucleate embryos donated from cycles in which the patient conceived, to investigate possible variability in transcript abundance between individual embryos. We have screened oocytes and embryos for a panel of genes including beta-actin (expressed in 24/28 oocytes, 6/6 pronuclear embryos), the integrins beta1 (17/28 oocytes, 6/6 pronuclear embryos) and beta5 (8/28 oocytes, 5/6 pronuclear embryos), and the apoptotic regulators BCL-2 (20/28 oocytes, 2/6 pronuclear embryos) and BAX (21/28 oocytes, 5/6 pronuclear embryos). The expression of the pro-apoptotic regulator BAX increased in human oocytes following prolonged periods of culture. Overall, patterns of gene transcript presence showed variation between embryos and this was independent of either zona removal or lysis conditions. Pronucleate embryos showed less variation, however, even sibling embryos from the patient did not express an identical subset of genes.

DNA, Complementary↗
PubMed2003

Waiting for in vitro fertilization treatment: spontaneous and ART live births.

This study analysed the live birth rates in 760 couples referred in 1994 to St Mary's Hospital, Manchester, a non-fee-paying National Health Service (NHS) centre, who had waited for up to 4 years for IVF treatment. These live birth rates were compared with those of 199 couples referred at a similar time to Manchester Fertility Services, a fee-paying unit, where they received IVF treatment shortly after referral. The waiting time was advantageous in that 17.8% (135 of 760) of the couples referred to St Mary's Hospital conceived without IVF treatment, 60% within one year of referral. However, the waiting time was detrimental to women aged 30-34 in whom treatment was delayed by 3-4 years. Only 26.8% (204 of 760) of couples originally referred eventually received NHS-funded IVF treatment at St Mary's. A waiting time not exceeding 18 months would allow most spontaneous conceptions and reduce the adverse effect of prolonged waiting on the take-up rate for treatment and on the chance of success in the older women.

Adult↗
PubMed2002

Apoptosis in the preimplantation mouse embryo: effect of strain difference and in vitro culture.

Cell death by apoptosis occurs predominantly in the inner cell mass (ICM) of the blastocyst, the cell population which carries the germ line and gives rise to the foetus. The frequency of apoptosis in blastocysts varies widely within outbred species such as human and cow. We have addressed the basis of this variation by examining the relative influence of strain difference and in vitro culture conditions on apoptosis, using embryos from two different strains of mice (MF1 and C57BL6/CBA) in two different culture media (M16 and kSOM). In both strains and all crosses apoptosis was first detected by nuclear fragmentation or TUNEL [Terminal deoxynucleotidyl transferase mediated d-UTP nick end-labelling] labelling at the early blastocyst stage. This was true for embryos which had developed in vivo, and in vitro in both M16 and kSOM. The apoptotic index in blastocysts was found to be significantly different between both media and strain (P < 0.0001). Blastocysts from MF1 x MF1 at equivalent stages had an apoptotic index of 32.4% in M16 and 20.3% in kSOM. Blastocysts from C57BL6/CBA x C57BL6/CBA had an apoptotic index of 19.3% in M16 and 14.4% in kSOM. When embryos of similar cell number were compared, a significantly greater apoptotic index was found for cultured MF1 x MF1 embryos with a cell number between 40 and 59 compared to similar directly flushed C57BL6/CBA embryos (P = 0.001), and MF1 embryos (P < 0.0005). MF1 x MF1 embryos and C57BL6/CBA x MF1 embryos of 60-79 cells had a greater apoptotic index in M16 than kSOM (P < 0.0005) but the difference between media was not significant for C57BL6/CBA x C57BL6/CBA. When strain was compared MF1 x MF1 embryos of 60-79 cells had a significantly greater apoptotic index than C57BL6/CBA x MF1 in both media (P < 0.0005 M16; P = 0.002 kSOM) and than C57BL6/CBA x C57BL6/CBA in M16 (P = 0.019). Our data suggest that genetic make-up and the chemical composition of simple medium are equally important in determining the level of apoptosis.

Analysis of Variance↗
PubMed2002

Fertility preservation in cancer patients.

This symposium was an international gathering of clinicians and scientists working in the field of preservation of fertility for male and female cancer patients and was organized by Professor Ettore Cittadini. Two days of invited lectures covered the spectrum of options for cryopreservation of fertility, from sperm, testicular tissue and germ cells, to eggs and ovarian tissue. The UK was represented by invited talks from Daniel Brison (sperm cryopreservation), John Radford (ovarian tissue cryopreservation), Kate Hardy (in vitro culture of follicles) and David Baird (ovarian tissue cryopreservation and regrafting in sheep).

Cryopreservation↗
PubMedDate not supplied

Ultrastructural preservation of ovarian cortical tissue cryopreserved in dimethylsulfoxide for subsequent transplantation into young female cancer patients.

Cytotoxic therapy in young women with cancer may cause loss of ovarian function, and ovarian cryopreservation has been proposed as a means of preserving fertility. The objective of this study is to assess ultrastructural preservation of follicles in frozen-thawed ovarian cortical strips, previously cryopreserved using dimethylsulfoxide and a standard slow-cool/rapid-thaw protocol. Ovarian cortical strips (patients, n=7) were thawed and fixed in glutaraldehyde for epoxy resin embedding electron microscopy according to conventional procedures. Oocytes were generally well preserved, on the basis of plasma-membrane integrity, uniformity of chromatin pattern, mitochondrial and rough endoplasmic reticulum (rER) cisternal integrity, and absence of cytoplasmic and intranuclear clear spaces. Frequently, rER cisternae were distended and intramitochondrial matrices lost. Granulosa cells showed somewhat variable preservation. Some were dark-staining; others exhibited washed-out cytoplasm containing damaged or artifactually expanded organelles. The consistently good preservation of oocytes and the good but more variable preservation of granulosa cells provides scientific validation of one component in the overall clinical procedure of attempting to reestablish fertility in young female patients after cytotoxic therapy for cancer.

Adult↗