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Biomedical subjects

William B Schoolcraft

Publications and source records attributed to William B Schoolcraft.

13 recordsLinked to original sources
PubMed2006

Proteomic analysis of individual human embryos to identify novel biomarkers of development and viability.

OBJECTIVE: To develop a method to analyze the proteome of individual human blastocysts and identify differentially expressed proteins prior to implantation. DESIGN: Experimental study. SETTING: Research environment. PATIENT(S): Couples undergoing infertility treatment donated with consent cryopreserved human cleavage-stage embryos for research. INTERVENTION(S): Individual embryos were extracted and analyzed by time-of-flight mass spectrometry. MAIN OUTCOME MEASURE(S): The protein expression profiles of individual embryos. RESULT(S): Differential protein expression profiles were observed between early and expanded blastocysts, as well as between developing blastocysts and degenerate embryos. Significantly, several up-regulated and down-regulated proteins were detected in degenerating embryos. A search in the protein databases highlighted several candidates, including an inhibitor of Tcf-4 (transcription factor mediating Wnt signaling) and an apoptotic protease-activating factor. CONCLUSION(S): This is the first study to successfully analyze the proteome of individual human embryos. This study has shown that protein expression profiles relate to morphology, with degenerating embryos exhibiting significant up-regulation of several potential biomarkers that might be involved in apoptotic and growth-inhibiting pathways.

Biomarkers↗
PubMed2006

Analysis of protein expression (secretome) by human and mouse preimplantation embryos.

OBJECTIVE: To analyze the protein production into the surrounding medium (secretome) of both human and mouse embryos and correlate these findings with ongoing blastocyst development. Along with improvements in culture systems, there is renewed focus on the development of noninvasive viability assays in human IVF. Because the majority of biologic functions are carried out by proteins, it is important to study the dynamics of the proteome during embryonic development and its response to both internal and external stimuli. DESIGN: Experimental study. SETTING: Research laboratory. PATIENT(S): Couples undergoing infertility treatment donated with consent spent culture media for research. INTERVENTION(S): Analysis by time-of-flight mass spectrometry. MAIN OUTCOME MEASURE(S): Protein profiles of spent culture media. RESULT(S): Distinctive and significantly different secretome profiles were observed at each embryonic developmental stage (P<0.05). Correlation of day 5 secretome data with ongoing blastocyst development revealed an 8.5-kDa protein biomarker that was significantly up-regulated (P<0.05). The best candidate for this protein biomarker was ubiquitin, which has been implicated in the implantation process of mammalian species. CONCLUSION(S): This approach to analyze the secretome should not only further our understanding of embryo physiology but provide the basis for the development of noninvasive assays of embryo viability in human IVF.

Animals↗
PubMed2005

Effect of myomectomy on the outcome of assisted reproductive technologies.

OBJECTIVE: To evaluate the impact of myomectomy on in vitro fertilization-embryo transfer (IVF-ET) and oocyte donation cycle outcome. DESIGN: Retrospective case-controlled study of consecutive fresh IVF-ET and oocyte donation patients during a 2-year interval. SETTING: Private assisted reproductive technology (ART) center. PATIENT(S): Patients with submucosal leiomyomata resected hysteroscopically (group A: 15 oocyte donor recipients; group 1 = 31 IVF-ET patients) and those with intramural components or strictly intramural leiomyomata that distorted or impinged upon the endometrial cavity resected at laparotomy (group B = 26 oocyte donor recipients; group 2 = 29 IVF-ET patients). INTERVENTION(S): Precycle hysteroscopic or abdominal myomectomy and subsequent fresh IVF-ET or oocyte donation. MAIN OUTCOME MEASURE(S): Results of controlled ovarian hyperstimulation as well as ongoing pregnancy and implantation rates were evaluated in comparison with contemporaneous patient groups without such lesions (group C = 552 oocyte donor recipients; group 3: 896 IVF-ET patients). RESULT(S): As would be expected, the mean number and size of leiomyomata were significantly larger in patients who underwent abdominal myomectomy. However, neither ongoing pregnancy nor implantation rates were significantly different in comparison with controls among either oocyte donor recipients (group A: 86.7%, 57.8%; group B: 84.6%, 55.2%; group C 77%, 49.1%). The findings were similar for those undergoing IVF-ET in comparison with controls (group 1: 61%, 24%; group 2: 52%, 26%; group 3: 53%, 23%). CONCLUSION(S): Precycle resection of appropriately selected clinically significant leiomyomata results in IVF-ET or oocyte donation cycle outcomes that are similar to controls.

Adult↗
PubMed2005

A proteomic analysis of mammalian preimplantation embryonic development.

Genetic studies on the mammalian preimplantation embryo are providing a wealth of information regarding gene expression. However, changes in the transcriptome do not always reflect cellular function or the complexity and diversity of the mammalian proteome with post-translational modifications or protein-protein interactions. To elucidate embryonic cellular function, a detailed understanding at the protein level is necessary. The aim of this study was to generate protein profiles of mammalian embryos throughout development, and to investigate the effects of oxygen concentration on the embryonic proteome. A protocol was developed to analyse small groups of embryos (n = 5) by time-of-flight mass spectrometry. F1 mice zygotes were cultured in G1/G2 sequential media with recombinant albumin (2.5 mg/ml) in 6% CO(2) and O(2) concentrations of either 5% or 20%. In vivo-developed embryos were flushed from the reproductive tract (day 4). Protein profiles were generated for all embryonic samples and statistical analysis revealed 32 potential proteins/biomarkers with significant changes (P < 0.05). Embryos generated under 5% O(2) more closely resembled in vivo-developed embryos. Under 20% O(2) conditions, embryos showed down-regulation of 10 proteins/biomarkers (masses between 4 to 20 kDa) (P < 0.05) confirming the pathological effects of oxygen during embryonic development. These data demonstrate for the first time the complexity of the mammalian preimplantation proteome. The unique protein profiles of in vivo-developed embryos and a panel of selected biomarkers represent optimal cellular function, against which comparisons can be made to facilitate improvements in mammalian assisted reproduction techniques procedures.

Animals↗
PubMed2004

Single blastocyst transfer: a prospective randomized trial.

OBJECTIVE: To determine the efficacy of single blastocyst transfer. DESIGN: Prospective randomized trial. SETTING: Private assisted reproductive technology unit. PATIENT(S): Forty-eight women undergoing IVF-embryo transfer with day 3 FSH 12 mm in diameter on day of hCG administration. INTERVENTION(S): Embryo culture to the blastocyst stage in sequential media G1/G2 followed by transfer of either one or two blastocysts. MAIN OUTCOME MEASURE(S): Implantation rate, ongoing pregnancy rate, and twinning. RESULT(S): The transfer of a single blastocyst resulted in an implantation and ongoing pregnancy rate of 60.9% with no twins. The transfer of two blastocysts resulted in an implantation rate of 56%, an ongoing pregnancy rate of 76% with a 47.4% incidence of twins. CONCLUSION(S): Single blastocyst transfer is an effective method of eliminating multiple births while maintaining high pregnancy rates in this selected group of patients.

Adult↗
PubMed2004

Extent of nuclear DNA damage in ejaculated spermatozoa impacts on blastocyst development after in vitro fertilization.

OBJECTIVE: To determine whether the extent of ongoing apoptotic cell death measured as the presence of DNA strand breaks in spermatozoa affects embryo development to the blastocyst stage in IVF. DESIGN: A prospective comparative study. SETTING: A university IVF clinic and a private IVF clinic. PATIENT(S): Men (n = 49) undergoing infertility treatment with IVF. INTERVENTION(S): After density gradient centrifugation preparation, part of the sperm sample was used for infertility treatment, and the rest was fixed in paraformaldehyde. Strand breaks in DNA that are indicative of apoptosis were detected by the in situ DNA nick end labeling (TUNEL) technique. A total of 15,000 spermatozoa from each sample were evaluated for TUNEL reactivity by flow cytometry. MAIN OUTCOME MEASURE(S): Percentage of ejaculated spermatozoa with DNA strand breaks indicative of apoptosis, blastocyst development rate, and pregnancy rate. RESULT(S): Blastocyst development showed a significant negative correlation with percentage TUNEL positivity in spermatozoa. When 20% was used as a cutoff for TUNEL positivity in sperm samples, the percentage of blastocyst development was 50% higher in the <20% TUNEL-positivity group (n = 27) compared with those with >/=20% TUNEL positivity (n = 22; 44.7% blastocyst development vs. 29.8%). Clinical pregnancy rates in these two groups were 52% vs. 44%, respectively. CONCLUSION(S): The extent of nuclear DNA fragmentation in prepared ejaculated spermatozoa used in IVF negatively correlates with blastocyst development. A larger series of patients needs to be assessed to determine whether this paternal effect on blastocyst development may also affect pregnancy outcome.

Apoptosis↗
PubMed2003

Changing the start temperature and cooling rate in a slow-freezing protocol increases human blastocyst viability.

OBJECTIVE: To determine the effect of start temperature and cooling rate of a slow freezing protocol on human blastocyst viability. DESIGN: Controlled-rate freezing of human blastocysts using different start temperatures and cooling rates. SETTING: Private assisted reproductive technology unit. PATIENT(S): Patients donated with consent cryopreserved pronucleate embryos. INTERVENTION(S): Culture of thawed pronucleate embryos in G III series media, containing hyaluronan, followed by cryopreservation of 36 blastocysts with subsequent noninvasive analysis of embryo metabolism. MAIN OUTCOME MEASURE(S): Pyruvate and glucose consumption and blastocyst reexpansion and quality. RESULT(S): Glucose consumption and blastocyst reexpansion after thaw were significantly higher when a start temperature of -6 degrees C and a cooling rate of 0.5 degrees C/min to -32 degrees C were used compared with a start temperature of 20 degrees C and a cooling rate of 2 degrees C to -6 degrees C, followed by cooling at 0.3 degrees C to -35 degrees C. Pyruvate uptake after thaw was not affected by the freezing procedure. Clinical use of the lower start temperature and quicker cooling rate, combined with culture in hyaluronan-based media, has led to the establishment of a 30% implantation rate. CONCLUSION(S): Human embryos cultured to the blastocyst stage in hyaluronan-based sequential media are readily cryopreserved and maintain their viability after thaw.

Blastocyst↗
PubMed2003

Management of endometriosis-associated infertility.

Management of infertility associated with endometriosis remains challenging. The clinician must rule out all other causes of infertility before creating a treatment plan. It is important to remember that women with infertility and endometriosis with tubal patency can conceive spontaneously, albeit at lower rates than in the fertile population. Surgical ablation or resection seems to provide benefit even in the absence of correctable anatomic defects. One should note, however, that the goal of surgery is not only to eliminate disease effectively but also to restore pelvic anatomy to normal. After reconstruction or in patients with less extensive disease, controlled ovarian hyperstimulation techniques potentially in conjunction with intrauterine inseminations can be effective. It is important to monitor patients carefully given the risk of high order multiple gestation reported with these techniques. IVF represents an effective means of bypassing the hostile peritoneal environment and anatomic distortion associated with this disease state. Although medical suppression of endometriosis alone has virtually no benefit in the asymptomatic patient, there seems to be significant benefit of pretreatment with GnRH agonists immediately before IVF cycle initiation. Whether only a specific subset or all patients with endometriosis would benefit from this approach has not yet been determined. The use of endometrial implantation markers may be helpful in this regard. The selection of the most effective approach to overcome infertility must be individualized and based on extent of disease, additional infertility factors, patient comfort, and a frank discussion of success rates and risks with patients.

Combined Modality Therapy↗
PubMed2003

Does surgical management of endometriosis within 6 months of an in vitro fertilization-embryo transfer cycle improve outcome?

PURPOSE: To assess the effect on cycle outcome of surgery for endometriosis performed in the 6 months prior to in vitro fertilization-embryo transfer (IVF-ET). METHODS: Retrospective analysis of all patients with a primary diagnosis of endometriosis undergoing IVF-ET during 12 consecutive months. The setting included tertiary care assisted reproductive technology program. Ninety-five consecutive cycles in candidates for autologous IVF-ET who had undergone surgical resection of endometriosis within 60 months of oocyte retrieval were evaluated. Five patients with persistent or recurrent endometriomas > 3 cm at the time of IVF-ET were excluded. Patients were divided into two groups based on the interval between the most recent surgical intervention and oocyte aspiration-Group I: < or = 6 months' interval (19 cycles); Group II: > 6 months' interval (76 cycles). RESULTS: Mean intervals between surgery and oocyte aspiration were significantly different between the groups (Gr I: 3.7 +/- 0.3 months; Gr II: 21.8 +/- 1.6 months; p < 0.001). There were no significant differences between groups with regards to age, extent of endometriosis, or results of ovarian stimulation and oocyte aspiration. Ongoing pregnancy rates (Gr I: 63.2%; Gr. II: 60.5%) were similar. Regression analyses revealed no correlation between implantation rates and either endometriosis score (r = -0.09) or surgery-oocyte aspiration interval (r = -0.13). CONCLUSIONS: The interval between surgical management of endometriosis and oocyte aspiration did not have an impact on IVF-ET cycle outcome in the absence of significant persistent or recurrent ovarian disease. Any effect of surgery on enhancing spontaneous conception may be overcome by the inherently greater impact of IVF-ET on implantation and pregnancy.

Embryo Transfer↗
PubMed2002

Effect of prolonged gonadotropin-releasing hormone agonist therapy on the outcome of in vitro fertilization-embryo transfer in patients with endometriosis.

OBJECTIVE: To evaluate the effect of a 3-month course of GnRH agonist administered immediately before IVF-ET in infertile patients with endometriosis. DESIGN: Prospective, randomized trial. SETTING: Three tertiary care assisted reproductive technology programs. PATIENT(S): IVF-ET candidates with surgically confirmed endometriosis. INTERVENTION(S): Twenty-five patients received three courses of a long-acting GnRH agonist, 3.75 mg i.m. every 28 days, followed by standard controlled ovarian hyperstimulation. Twenty-six patients received standard controlled ovarian hyperstimulation with mid-luteal phase GnRH agonist down-regulation or microdose flare regimens. MAIN OUTCOME MEASURE(S): Response to controlled ovarian hyperstimulation, ongoing pregnancy rates per cycle, group implantation rates, and implantation rate per embryo transfer procedure. RESULT(S): The extent of surgically confirmed endometriosis was greater in patients who received the long-acting GnRH regimen for 3 months before IVF-ET. The groups did not differ significantly in terms of dose or duration of gonadotropin stimulation, number of oocytes retrieved, fertilization rate, or number of embryos transferred. Patients who received the long-acting GnRH regimen had significantly higher ongoing pregnancy rates (80% vs. 53.85%) and a trend toward higher implantation rates (42.68% vs. 30.38%). CONCLUSION(S): Prolonged use of GnRH agonist before IVF-ET in patients with endometriosis resulted in significantly higher ongoing pregnancy rates than did standard controlled ovarian hyperstimulation regimens. No deleterious effect on ovarian response was observed.

Adult↗
PubMedDate not supplied

Physiology and culture of the human blastocyst.

The human embryo undergoes many changes in physiology during the first 4 days of life as it develops and differentiates from a fertilized oocyte to the blastocyst stage. Concomitantly, the embryo is exposed to gradients of nutrients within the female reproductive tract and exhibits changes in its own nutrient requirements and utilization. Determining the nature of such nutrient gradients in the female tract and the changing requirements of the embryo has facilitated the formulation of stage-specific culture media designed to support embryo development throughout the preimplantation period. Resultant implantation rates attained with the culture and transfer of human blastocysts are higher than those associated with the transfer of cleavage stage embryos to the uterus. Such increases in implantation rates have facilitated the establishment of high pregnancy rates while reducing the number of embryos transferred. With the introduction of new scoring systems for the blastocyst and the non-invasive assessment of metabolic activity of individual embryos, it should be possible to move to single blastocyst transfer for the majority of patients.

Blastocyst↗