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Dive into the research topics where Robert N. Clarke is active.

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Featured researches published by Robert N. Clarke.


Journal of Assisted Reproduction and Genetics | 1998

Effects of endometriomas on ooccyte quality, embryo quality, and pregnancy rates in in vitro fertilization cycles : A prospective, case-controlled study

Elena H. Yanushpolsky; Craig L. Best; Katharine V. Jackson; Robert N. Clarke; Robert L. Barbieri; Mark D. Hornstein

Purpose:The effect of endometriomas on oocyte quality, embryo quality, and pregnancy rates in in vitro fertilization (IVF) cycles was evaluated.Methods:Forty-five women had “chocolate” cysts aspirated at the time of oocyte retrieval, and cyst fluid CA 125 levels were measured to ascertain presence of “true” endometriomas. Fifty-seven women without any complex cysts at the time of oocyte retrieval served as controls. IVF cycle outcome parameters were compared between the two groups.Results:Women with endometriomas experienced a significantly higher rate of early pregnancy loss compared to controls (47 vs 14%). There was also a trend toward fewer oocytes retrieved and fewer embryos reaching at least the four-cell stage 48 hr after retrieval in patients with true endometriomas vs controls.Conclusions:The presence of endometriomas at the time of oocyte retrieval is associated with increased rates of early pregnancy losses. The number of oocytes retrieved and the embryo quality may also be affected adversely in the presence of endometriomas.


Fertility and Sterility | 1998

Multinucleation in normally fertilized embryos is associated with an accelerated ovulation induction response and lower implantation and pregnancy rates in in vitro fertilization-embryo transfer cycles

Katharine V. Jackson; Elizabeth S. Ginsburg; Mark D. Hornstein; Mitchell S. Rein; Robert N. Clarke

OBJECTIVEnTo determine if multinucleation in normally fertilized embryos is indicative of poor developmental or clinical pregnancy prognosis and to examine the ovulation induction characteristics associated with multinucleation.nnnDESIGNnRetrospective review.nnnSETTINGnA tertiary care institution.nnnPATIENT(S)nPatients undergoing IVF-ET cycles (exclusive of other assisted reproductive technologies).nnnMAIN OUTCOME MEASURE(S)nCycles in which embryos had at least 1 multinucleated blastomere were compared with cycles in which all blastomeres exhibited no nucleus or a single nucleus (control).nnnRESULT(S)nWhen >50% of transferred embryos contained multinucleated blastomeres there was a significant reduction in implantation (3.4% vs. 14.7%), clinical pregnancy (9.1% vs. 29.1%), and live birth rates (7.5% vs. 27.6%) when compared with transfers of control embryos. In conjunction with this finding, multinucleate cycles had higher E2 levels and more follicles on the day of hCG administration, a higher number of oocytes retrieved, a higher fertilization rate, and more embryos transferred per patient than did the cycles that produced control embryos. When multinucleated embryos were present, but not transferred, the developmental capacity of the sibling embryo was reduced.nnnCONCLUSION(S)nThe evaluation of nuclear status using simple light microscopy is predictive of embryo developmental capacity and should be included in the embryo scoring system. The presence of multinucleated blastomeres in normally fertilized embryos is associated with a more effusive response to gonadotropin therapy and is indicative of a poor developmental outcome and lower clinical pregnancy rates.


Journal of Assisted Reproduction and Genetics | 2000

The prognostic value of age and follicle-stimulating hormone levels in women over forty years of age undergoing in vitro fertilization.

Andrew H. Watt; Anna T. R. Legedza; Elizabeth S. Ginsburg; Robert L. Barbieri; Robert N. Clarke; Mark D. Hornstein

AbstractPurpose: Basal follicle-stimulating hormone (FSH) and ageare predictors of successful outcome in in vitro fertilization(IVF). More recently, the clomiphene citrate challenge test(CCCT) has been proposed as a better way to predict IVFoutcome than FSH alone. The purpose of this study was todetermine which indicator of ovarian reserve—basal(day 3) FSH or the CCCT—is the better predictor of IVF successin the critical age group of women over the age of 40.nMethods: In this retrospective study, basal FSH andclomiphene-stimulated FSH levels from 104 women whounderwent 175 cycles of IVF were analyzed.nResults: Neither basal FSH level nor stimulated FSH levelalone were statistically significant predictors of IVF success;however, no patient with a day 3 FSH level >11.1 mIU/mlor a stimulated day 10 FSH level >13.5 mIU/ml conceivedand carried a pregnancy. All ongoing pregnancies occurredin the first two cycles of IVF.nConclusions: Clear prognostic cutoff values were found topredict IVF success in women over age 40. IVF programsshould consider limiting the number of cycles of IVF inwomen above age 40.


Journal of Assisted Reproduction and Genetics | 1999

The Graafian follicle is a site of L-ascorbate accumulation.

Tomasz Paszkowski; Robert N. Clarke

Purpose:Our purpose was to evaluate the L-ascorbate level in human preovulatory follicular fluid and to quantify the blood/follicle gradient for vitamin C. The effect of smoking on the follicular L-ascorbate concentration was studied. The correlations were tested between follicular L-ascorbate and follicle size and oocyte maturity.Methods:In 65 women undergoing in vitro fertilization, samples of follicular fluid and blood serum were collected. Biochemical analyses included L-ascorbate determinations by a colorimetric method and cotinine measurements by a radioimmunoassay.Results:The average follicular fluid:serum ratio for L-ascorbate was 1:68. Ascorbate levels in follicular fluid and serum were significantly correlated. The follicular L-ascorbate level did not correlate with the follicle size and the oocyte maturity grade. Insignificantly lowered follicular L-ascorbate levels were observed in smokers.Conclusions:The extracellular compartment of the Graafian follicle is a site of an ascorbate accumulation. Exposure to tobacco smoke does not significantly diminish the intrafollicular pool of L-ascorbate.


Fertility and Sterility | 1992

The appearance of one-pronuclear human oocytes is associated with a better ovulation-induction response and successful pregnancy outcome *

Katharine V. Jackson; Aida Nureddin; Robert N. Clarke; Mark D. Hornstein; Mitchell S. Rein; Andrew J. Friedman

OBJECTIVEnTo study the relationship between the presence of one-pronuclear oocytes in in vitro fertilization (IVF) patients and ovulation-induction response, oocyte and embryo development, and clinical outcome.nnnDESIGNnRetrospective analysis of 535 consecutive IVF retrievals. Retrievals in which one or more oocytes exhibited one pronucleus were compared with retrievals in which no one-pronuclear oocytes (control) were observed. The following one-pronuclear versus control subgroups were also examined: leuprolide acetate/human menopausal gonadotropin (LA/hMG) ovulation inductions, high estradiol (E2) response cases, and retrievals in which a large number of oocytes (greater than or equal to 15) were recovered.nnnSETTINGnBrigham and Womens Hospital, a tertiary care, university-affiliated hospital.nnnPATIENTSnThree hundred forty-six IVF patients were treated between January 1989 and May 1991.nnnMAIN OUTCOME MEASURESnParameters examined included E2 concentration and number of follicles with maximum diameter greater than or equal to 12 mm on day of human chorionic gonadotropin administration; number of total and mature oocytes retrieved; total fertilization rates; number of embryos; and percent per retrieval of embryo transfers (ETs), clinical pregnancies, and ongoing-livebirths.nnnRESULTSnThe one-pronuclear patients had higher E2 levels and larger number of follicles, yielded significantly more total and mature oocytes, had a higher overall fertilization rate, produced more embryos, and had higher ET, clinical pregnancy and ongoing-livebirth rates per retrieval than did the control patients. Analysis of the subgroup populations revealed no significant differences in the majority of the main outcome measures studied; however, the one-pronuclear patients yielded significantly more total and mature oocytes per retrieval.nnnCONCLUSIONSnAlthough there was an increase in the clinical and ongoing-livebirth pregnancy rates (PRs) in one-pronuclear patients, this was probably associated with an improved ovulation-induction response in the one-pronuclear patients. They achieved significantly higher E2 levels, recruited a larger number of follicles, and yielded more oocytes and embryos per retrieval than the control patients. When only the LA/hMG, E2 greater than or equal to 1,500 pg/mL, or the greater than or equal to 15 oocytes/case retrievals were analyzed, the PRs were no longer different; however, the one-pronuclear patients still yielded significantly more total and mature oocytes per retrieval than the controls. Therefore, the appearance of one-pronuclear oocytes is probably associated with the maturation stage of the oocytes obtained and is indicative of an ovulation induction in which a large number of preovulatory, metaphase II oocytes have been recruited.


Journal of Assisted Reproduction and Genetics | 1995

Screening of maternal sera using a mouse embryo culture assay is not predictive of human embryo development or IVF outcome.

Robert N. Clarke; Patricia M. Griffin; John D. Biggers

PurposeMaternal serum is commonly added to media used for human IVF but can vary widely in its ability to support the development of human embryos in vitro.The objective of this study was to determine if the screening of maternal serum with a mouse one-cell embryo culture assay would be useful in predicting human embryo development and clinical outcome following IVF.MethodsTwenty-two individual serum samples from IVF patients were used as a supplement (7.5%) to Hams F-10 media for culturing human embryos. All embryos were evaluated at the time of transfer for stage of development and embryo quality. Each serum sample was also tested for its ability to support mouse embryo development. One-cell embryos were recovered from superovulated female mice and cultured in serum-supplemented media. Mouse blastocyst development was assessed after 96 h of incubation.ResultsNo correlation was found between mouse blastocyst formation and human embryo development in media supplemented with maternal sera. Similarly, there was no association between the development of mouse blastocysts and clinical outcome following IVF. A subanalysis of patients whose sera tested poorly on the mouse assay again revealed no association between mouse and human embryo development.ConclusionMouse embryo development in media containing human serum did not predict development of human embryos in vitroor clinical outcome following IVF. There would be little benefit to screening maternal sera using a mouse embryo culture system for determining its suitability for use in human IVF.


Journal of Assisted Reproduction and Genetics | 1993

A self-programmable in vitro fertilization/gamete intrafallopian transfer patient database management system for MacIntosh computers.

Katharine V. Jackson; Robert N. Clarke; Aida Nureddin; Mark D. Hornstein; Mitchell S. Rein; Andrew J. Friedman

PurposeOur purpose was to develop a data processing system for a large in Vitro Fertilization/Gamete Intrafallopian Transfer (IVF/GIFT) practice which would (1) require minimal data entry time, (2) be easy to operate, (3) be simple to construct (no knowledge of procedural language or programming necessary), and (4) quickly collate and reduce data.ResultsA database management system was successfully constructed on an Apple MacIntosh computer which met the above criteria. The key elements of this database were its user-friendly features (MacIntosh-based system), adaptability (user was constantly able to update and revise the program as informational needs changed), and ability to perform complex searches and data analyses imposed by the individual operators.ConclusionsThe software and hardware described in this report were found to be highly effective in meeting the ever-changing administrative and clinical needs of our IVF/GIFT program.


Fertility and Sterility | 1996

A randomized clinical trial to evaluate the clinical effects of split- versus single-dose human menopausal gonadotropins in an assisted reproductive technology program*

Janis H. Fox; Katharine V. Jackson; Mitchell S. Rein; Mark D. Hornstein; Robert N. Clarke; Andrew J. Friedman

OBJECTIVEnTo compare the effect of twice (split) versus once (single) daily administration of hMG on assisted reproductive technology (ART) cycle parameters.nnnDESIGNnA randomized clinical trial.nnnSETTINGnHospital-based academic ART program.nnnPATIENTSnA total of 171 patients undergoing their initial ART cycle were enrolled. All patients received one of two hMG regimens and were excluded from the study if they were receiving medications other than leuprolide acetate (LA) and hMG for ovulation induction.nnnINTERVENTIONSnSubjects were randomized to receive an initial dose of 300 IU/d of hMG in either split-dose (i.e., 150 IU twice daily) or single-dose fashion for four successive days after down-regulation with LA. Thereafter, their daily dose was individualized, maintaining a split-or single-dose schedule. All cycles were managed in accordance with our standard ART protocols.nnnMAIN OUTCOME MEASURESnCancellation rate, total hMG requirements, number of days treated with hMG, E2 and P responses, oocyte yield and maturity, fertilization rate, total number of embryos, embryo quality, number of embryos transferred, implantation rate, clinical and ongoing-delivered pregnancy rates.nnnRESULTSnSplit-dose hMG administration resulted in a significantly higher implantation rate, but significantly lower normal and polyspermic fertilization rates than single-dose hMG administration. No significant differences were noted between the two dosage protocols with respect to the other outcome measures.nnnCONCLUSIONSnSplit-dose hMG administration may be associated with significantly higher implantation rates; single-dose hMG with significantly higher fertilization rates. Although our data also demonstrate a trend toward higher clinical and ongoing-delivered pregnancy rates with split-dose therapy, demonstration of a significant difference would require a multicenter trial. Based on our data, clinicians may want to consider split-dose therapy for patients with repeated implantation failures.


Obstetrical & Gynecological Survey | 2002

Smoking induces oxidative stress inside the graafian follicle

T. Paszkowski; Robert N. Clarke; Mark D. Hornstein

BACKGROUNDnA growing body of evidence indicates that pro-oxidant/antioxidant balance inside ovarian follicles plays an important role in folliculogenesis. Over 20% of women of reproductive age in Europe and the USA regularly smoke cigarettes. The impact of tobacco smoking on the intrafollicular markers of oxidative stress has not been fully elucidated. The objective of the present study was to test the hypothesis that cigarette smoking affects the intrafollicular redox milieu.nnnMETHODSnIn follicular fluid samples originating from 108 IVF patients, lipid peroxidation was assessed by the thiobarbituric reactive substances method and total antioxidative capacity was quantified by the luminol enhanced chemiluminescence method. The level of patients exposure to the cigarette smoke was evaluated by measuring the follicular fluid cotinine concentration by means of radioimmunoassay.nnnRESULTSnIntrafollicular exposure to cigarette smoke metabolites was associated with a significant increase in follicular lipid peroxidation intensity (P < 0.001), which was accompanied by a significant decrease in the local antioxidative potential (P = 0.004).nnnCONCLUSIONnThe results indicate that active smoking affects the pro-oxidant/antioxidant balance inside the pre-ovulatory ovarian follicle by inducing intrafollicular oxidative stress. This provides another possible explanation for impaired folliculogenesis in female smokers.


Human Reproduction | 2002

Smoking induces oxidative stress inside the Graafian follicle

T. Paszkowski; Robert N. Clarke; Mark D. Hornstein

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Mark D. Hornstein

Brigham and Women's Hospital

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Katharine V. Jackson

Brigham and Women's Hospital

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Mitchell S. Rein

Brigham and Women's Hospital

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Andrew J. Friedman

Brigham and Women's Hospital

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Aida Nureddin

Brigham and Women's Hospital

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Janis H. Fox

Brigham and Women's Hospital

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Robert L. Barbieri

Brigham and Women's Hospital

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Andrew H. Watt

Brigham and Women's Hospital

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Anna T. R. Legedza

Beth Israel Deaconess Medical Center

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