Objective: To determine the incidence of premature luteinization in patients with polycystic ovary syndrome (PCOS) undergoing controlled ovarian hyperstimulation (COH) with exogenous gonadotropin/GnRH antagonist (GnRH-a); to compare clinical outcomes in patients with and without premature luteinization.Design: Retrospective case series.Setting: IVF clinic.Patient(s): Thirty-five treatment cycles in 30 patients with PCOS.Intervention(s): Controlled ovarian hyperstimulation with gonadotropin/GnRH-a protocol.Main Outcome Measure(s): Premature luteinization defined as a P concentration of >= 1.3 ng/mL on the day of hCG administration; number of oocytes and two pronuclei (2PN) embryos; implantation and clinical pregnancy rates (PR).Result(s): The incidence of premature luteinization was 28%. Compared with those without premature luteinization, patients with premature luteinization had a higher number of oocytes retrieved (24.1 +/- 13.3 vs. 12.0 +/- 5.9) and greater number of mature oocytes (19.7 +/- 11.7 vs. 9.5 +/- 4.5), respectively. The number of good quality embryos and embryos transferred was not significantly different between groups. Although implantation rates (56% vs. 40%) and clinical PRs (36% vs. 30%) were higher in patients without premature luteinization, the differences were not statistically significant.Conclusion(s): The patients with PCOS with premature luteinization had a higher number of oocytes retrieved and mature oocytes, and similar clinical PRs as patients with PCOS without premature luteinization. (Fertil Steril (R) 2009;91:1755-9. (C)2009 by American Society for Reproductive Medicine.)

OBJECTIVE: To determine if there is a difference in outcome in patients with PCOS who underwent COS with Gonadotropin/GnRH-agonist vs Gonadotropin/GnRH-antagonist protocols for IVF.DESIGN: Retrospective clinical case-series.MATERIALS AND METHODS: We evaluated the outcome of IVF in patients diagnosed with PCOS who underwent IVF with Gonadotropin/GnRH-agonist protocol (n=720), compared to Gonadotropin/GnRH-antagonist protocol (n=48). Cycle data analyzed included patient age, infertility diagnosis, BMI, number of days of oral contraceptive pills, total dose of gonadotropin administered, number of stimulation days and number of follicles >12 mm. Data from the day of hCG administration included cycle day, estradiol (E2), luteinizing hormone (LH) and progesterone (P4) levels. Outcome data analyzed included number of oocytes, di-pronucleate (2PN) eggs, number of morphologically good embryos, number of embryos transferred, number of embryos frozen, cycle cancellation rate and clinical pregnancy rates. The outcomes were evaluated using ANOVA statistical analysis. P value <0.05 was considered statistically significant.RESULTS: Our data shows that PCOS patients who underwent COS with Gonadotropin/GnRH-antagonist had a lower E2 level, a higher number of 2PN eggs and a higher number of morphologically good embryos.Table 1GnRH-agonistGnRH-antagonistP valueCycles72048BMI31.1± 3.933.4± 4.10.5OCP Days26.0± 18.823.8± 9.90.2Total FSH2796± 13962557± 15940/2Total hMG73 ±610559± 7880/0002Stimulation Days9.9± 0.110.3± 0.40.4Follicles >12 mm10.9± 8.311.3± 8.90.7E2pg/mL2115± 12291521± 1750.001P4 ng/mL0.58± 2.30.75± 0.60.6LHmIU/mL0.80 ±1.20.95±1.10.4# Oocytes12.0± 6.613.8± 9.80.062PN7.1± 4.88.6 ±5.90.03Day 3 good embryos1.5± 2.12.3± 3.10.02ET1.7± 0.81.8± 0.90.8Embryos Cryo1.2± 3.22.0± 3.10.9ancellation Cycles75/720 (10%)8/48 (17%)0.2Pregnancy/Cycle34/720 (47%)18/48 (37%)0.4Pregnancy/ET34/605 (56%18/40 (45%) Open table in a new tab OBJECTIVE: To determine if there is a difference in outcome in patients with PCOS who underwent COS with Gonadotropin/GnRH-agonist vs Gonadotropin/GnRH-antagonist protocols for IVF. DESIGN: Retrospective clinical case-series. MATERIALS AND METHODS: We evaluated the outcome of IVF in patients diagnosed with PCOS who underwent IVF with Gonadotropin/GnRH-agonist protocol (n=720), compared to Gonadotropin/GnRH-antagonist protocol (n=48). Cycle data analyzed included patient age, infertility diagnosis, BMI, number of days of oral contraceptive pills, total dose of gonadotropin administered, number of stimulation days and number of follicles >12 mm. Data from the day of hCG administration included cycle day, estradiol (E2), luteinizing hormone (LH) and progesterone (P4) levels. Outcome data analyzed included number of oocytes, di-pronucleate (2PN) eggs, number of morphologically good embryos, number of embryos transferred, number of embryos frozen, cycle cancellation rate and clinical pregnancy rates. The outcomes were evaluated using ANOVA statistical analysis. P value <0.05 was considered statistically significant. RESULTS: Our data shows that PCOS patients who underwent COS with Gonadotropin/GnRH-antagonist had a lower E2 level, a higher number of 2PN eggs and a higher number of morphologically good embryos.

To examine the response to controlled ovarian hyperstimulation with Gonadotropin and GnRH-Antagonist protocol in In Vitro Fertilization cycles in different infertility etiologies Retrospective observational study. The outcome of controlled ovarian hyperstimulation cycles using Gonadotropin and GnRH-Antagonist protocol for in In Vitro Fertilization were compared between patients diagnosed with decreased ovarian reserve (n=40), endometriosis (n=21), male factor (n=85), tubal factor (n=40), unexplained infertility (n=25) and PCOS (n=22). Patients cycle data collected included: age, infertility diagnosis, peak Estradiol level on the day of hCG administration, number of follicles > 16 mm, number of oocytes retrieved, number of 2PN embryos developed, number of embryos transferred, embryos frozen, progesterone level, LH level and occurrence of pregnancy. Statistical analysis was performed using JMP 5.0 software. The values are presented as mean ± standard deviation. IVF outcome following controlled ovarian hyperstimulation with Gonadotropin and GnRH-Antagonist Tabled 1 Controlled ovarian hyperstimulation for IVF-ET with GnRH-Antagonist protocol is an effective alternative hyperstimulation protocol. The results suggest that GnRH-Antagonist protocol is a viable option of controlled ovarian hyperstimulation in patients with different etiologies with the benefits of no initial flare up effect, no estrogen deprivation symptoms, reduced gonadotropin requirements and rapid suppression of LH/FSH during all phases of menstrual cycles.

To compare serum hCG concentrations measured on the twelfth day after embryo transfer (D12) in autologous IVF and recipients of donated oocytes. D12 hCG concentrations in 577 women (younger than age 35) who had clinical pregnancies with autologous fresh embryo transfers between January 2001 and December 2003 were compared with D12 hCG concentrations of clinical pregnancies resulting from 68 egg donation cycles during the same time period. All women underwent GnRH agonist suppression and controlled ovarian stimulation with exogenous gonadotropins. Ultrasound-guided transvaginal follicle aspiration was performed 36 hr after hCG administration for autologous IVF cycles and 34 hr after hCG administration for egg donation cycles. Recipients of donated oocytes were synchronized using oral contraceptive pills (OCP) and Lupron down-regulation (LDR) followed by an oral Estrace and intramuscular (IM) Progesterone (EP) protocol. Embryo transfers were all performed 3 days after egg retrieval. Luteal support was achieved with only IM progesterone in all autologous IVF cycles, and with a combination of oral Estrace and IM progesterone in all recipients of donor oocytes. At 12 days following embryo transfer, serum hCG level of each patient was determined by a fluoroimmunometric assay system. Serum hCG values for viable and non-viable pregnancies were compared by Student's t test. The median D12 hCG concentrations were 167.00 IU/L and 223.0 IU/L for singleton autologous and egg donation pregnancies, respectively. Patients with singleton pregnancies that resulted from fresh autologous embryo transfers had significantly lower median D12 hCG levels (p<0.01) than patients with singleton pregnancies resulting from egg donation cycles. Twin pregnancies resulting from autologous IVF cycles had a median D12 hCG concentration of 306.8 IU/L which was also significantly lower (p=0.005) than 418 IU/L, the D 12 serum hCG concentrations in twin pregnancy of egg donation IVF cycles. Serum hCG concentrations on D 12 after embryo transfer were significantly higher in pregnant recipients of donated oocytes than in autologous IVF pregnancies. Our data suggests that embryo implantation may occur sooner in egg donation cycles compared to autologous IVF cycles.

To determine the incidence of premature luteinization in patients with Polycystic Ovarian Syndrome (PCOS) using GnRH-Antagonist protocol in IVF cycles and correlation with outcome. Retrospective case control study. Twenty two patients diagnosed with PCOS with a prior unsuccessful IVF cycle using a GnRH-Agonist protocol underwent controlled ovarian hyperstimulation with GnRH-Antagonist between 03/2002 and 12/2003. Premature luteinization was defined as a progesterone level >1.3 ng/ml on day of hCG. Data collected included: age, peak estradiol, and progesterone and LH levels on the day of hCG. In addition, number of eggs retrieved, number of embryos developed, embryos transferred, embryos frozen, implantation rate and pregnancy rate were recorded. Statistical analysis was performed using ANOVA and Chi square methodology. The incidence of premature luteinization was 50% in patients with PCOS who used a GnRH-Antagonist protocol for IVF. Implantation rate (36.36% vs 22.73%, p=0.03), and pregnancy rate (73% vs 18%, p=<0.0001) were significantly higher in PCOS patients without premature luteinization. Implantation and pregnancy rates were significantly greater in PCOS patients without evidence of premature luteinization when using a GnRH-Antagonist protocol. The occurrence of premature luteinization occurs frequently, and if it occurs has a negative effect on pregnancy rate.

ObjectiveThe objective of this study was to determine if there is any correlation between paternal age and outcome in egg donation cycles.DesignRetrospective observational.Materials and methods204 donor egg cycles conducted in 2001–2003 were included in this study. To eliminate female age factor we only included donors age between 21–32 (inclusive). Cases were grouped according to the age of the sperm provider, =55 (n=5). Egg donors were down-regulated using a standard OCP-GnRH agonist protocol and COH was achieved using rec-hFSH. When the leading follicle reached a diameter >=18mm and two other >=16mm, final follicle maturation was induced with 10,000 IU of uhCG or 250 ug of rec-hCG. Oocyte retrieval was scheduled 34 hours post hCG and the oocytes retrieved were fertilized with IVF or ICSI. Embryos were transferred on day 3. Statistical analyses were done using Welch's ANOVA and Fisher exact test as required; p-values <0.05 were considered statistically significant.ResultsThere were no significant difference in either ongoing pregnancy rates or implantation rates for the different paternal age groups.Conclusion ObjectiveThe objective of this study was to determine if there is any correlation between paternal age and outcome in egg donation cycles. The objective of this study was to determine if there is any correlation between paternal age and outcome in egg donation cycles. DesignRetrospective observational. Retrospective observational. Materials and methods204 donor egg cycles conducted in 2001–2003 were included in this study. To eliminate female age factor we only included donors age between 21–32 (inclusive). Cases were grouped according to the age of the sperm provider, =55 (n=5). Egg donors were down-regulated using a standard OCP-GnRH agonist protocol and COH was achieved using rec-hFSH. When the leading follicle reached a diameter >=18mm and two other >=16mm, final follicle maturation was induced with 10,000 IU of uhCG or 250 ug of rec-hCG. Oocyte retrieval was scheduled 34 hours post hCG and the oocytes retrieved were fertilized with IVF or ICSI. Embryos were transferred on day 3. Statistical analyses were done using Welch's ANOVA and Fisher exact test as required; p-values <0.05 were considered statistically significant. 204 donor egg cycles conducted in 2001–2003 were included in this study. To eliminate female age factor we only included donors age between 21–32 (inclusive). Cases were grouped according to the age of the sperm provider, =55 (n=5). Egg donors were down-regulated using a standard OCP-GnRH agonist protocol and COH was achieved using rec-hFSH. When the leading follicle reached a diameter >=18mm and two other >=16mm, final follicle maturation was induced with 10,000 IU of uhCG or 250 ug of rec-hCG. Oocyte retrieval was scheduled 34 hours post hCG and the oocytes retrieved were fertilized with IVF or ICSI. Embryos were transferred on day 3. Statistical analyses were done using Welch's ANOVA and Fisher exact test as required; p-values <0.05 were considered statistically significant. ResultsThere were no significant difference in either ongoing pregnancy rates or implantation rates for the different paternal age groups. There were no significant difference in either ongoing pregnancy rates or implantation rates for the different paternal age groups. Conclusion

Objective: To determine the predictive value of serum hCG concentrations measured on the twelfth day after embryo transfer (D12) as a marker to distinguish between viable and non-viable pregnancies.Design: Two thousand four hundred six women who had fresh embryo transfers between January 2000 and December 2002 were studied retrospectively. Patients who had serum hCG concentrations higher than 5IU/l on D12 post embryo transfer were stratified and evaluated.Materials and Methods: All women underwent GnRH agonist suppression and controlled ovarian stimulation with gonadotropin administration. Transvaginal follicle aspiration was performed 36 hr after hCG administration and embryo transfers performed on the third post retrieval day. On day 12 following embryo transfer, serum hCG level of each patient was determined by a fluoroimmunometric assay system. Serum hCG values for viable and non-viable pregnancies were compared by Student's t test.Results: The median hCG concentration was 161.00 IU/l for viable autologous singleton pregnancies. The median hCG concentration in viable multiple pregnancies was 200% higher than in singleton pregnancies with a median value of 321.42 IU/l. Patients with singleton pregnancies that resulted spontaneous abortion (sab) had lower median hCG levels (126.98 IU/l, p<0.01) than viable singleton pregnancies. Multiple pregnancies which resulted in an sab had a median hCG concentration of 196.54 IU/l which was also significantly lower compared to serum hCG concentrations in live multiple birth/ongoing pregnancies. Patients identified as having a biochemical pregnancy were found to have median hCG levels of 36.15 IU/l. Patients with ectopic pregnancies were also associated with low hCG values with the median concentration of 42.56 IU/l.Conclusion: Serum hCG concentration on day 12 following embryo transfer may be a useful prognostic tool in counseling patients regarding pregnancy outcome. Objective: To determine the predictive value of serum hCG concentrations measured on the twelfth day after embryo transfer (D12) as a marker to distinguish between viable and non-viable pregnancies. Design: Two thousand four hundred six women who had fresh embryo transfers between January 2000 and December 2002 were studied retrospectively. Patients who had serum hCG concentrations higher than 5IU/l on D12 post embryo transfer were stratified and evaluated. Materials and Methods: All women underwent GnRH agonist suppression and controlled ovarian stimulation with gonadotropin administration. Transvaginal follicle aspiration was performed 36 hr after hCG administration and embryo transfers performed on the third post retrieval day. On day 12 following embryo transfer, serum hCG level of each patient was determined by a fluoroimmunometric assay system. Serum hCG values for viable and non-viable pregnancies were compared by Student's t test. Results: The median hCG concentration was 161.00 IU/l for viable autologous singleton pregnancies. The median hCG concentration in viable multiple pregnancies was 200% higher than in singleton pregnancies with a median value of 321.42 IU/l. Patients with singleton pregnancies that resulted spontaneous abortion (sab) had lower median hCG levels (126.98 IU/l, p<0.01) than viable singleton pregnancies. Multiple pregnancies which resulted in an sab had a median hCG concentration of 196.54 IU/l which was also significantly lower compared to serum hCG concentrations in live multiple birth/ongoing pregnancies. Patients identified as having a biochemical pregnancy were found to have median hCG levels of 36.15 IU/l. Patients with ectopic pregnancies were also associated with low hCG values with the median concentration of 42.56 IU/l. Conclusion: Serum hCG concentration on day 12 following embryo transfer may be a useful prognostic tool in counseling patients regarding pregnancy outcome.

Objective: Delayed childbearing has resulted in a significant increase in the population of women over 40 years of age attempting assisted reproduction treatments. The objective of this study is to supply more detailed information on pregnancy rates and live birth rates on counseling these patients. Design: 799 women between the ages 40 and 45 who had initiated an IVF cycle between January 2000 and December 2002 were evaluated. Age at treatment, number of oocytes retrieved, inseminated and fertilized normally, the number of embryos transferred, number of sacs and pregnancy outcome were analyzed. Materials and Methods: Patients had FSH and estradiol levels on cycle day 3, most also had clomiphene citrate challenge tests which were normal. Women age 43 and over were individually screened by a review team prior to cycling to predict whether the risk was offset by the potential benefit. All women underwent controlled ovarian stimulation with a GnRH agonist in combination with gonadotropin administration. Ultrasound guided transvaginal follicle aspiration was performed 36 hr after hCG administration and embryo transfers performed on the third day after retrieval. Clinical pregnancy indicated by a gestational sac which could be seen on ultrasound examination five weeks after embryo transfer. Live birth information was collected from the patient or her physician. Statistical analysis included Chi-square for categorical data and Student's t-test for continuous variables. A p <0.05 was considered significant. Results: Tabled 1 Conclusion: While patients between 40–42 years of age can expect significantly reduced but reasonable pregnancy and live birth rates, the chance for successful outcomes are extremely low over 42 years of age. Women seeking infertility treatment who are 43 years old and beyond even with reasonable ovarian reserve testing, should be counseled extensively on sharp decline in live birth rates and be offered alternative treatments such as donor oocytes.

Human chorionic gonadotropin (hCG) is administered routinely to women to induce final maturation of oocytes prior to follicular aspiration and isolation of oocytes for insemination in vitro. A recombinant hCG (rec-hCG) became available recently and has been used for this purpose. Objective: To compare the efficacy of rec-hCG to preparations of human urinary hCG (u-hCG) in the isolation and insemination of oocytes in vitro. Design: 198 treatment cycles in which the patient was administered rec-hCG (Ovidrel, Serono) between January and June of 2002 were identified and compared retrospectively to 638 age-matched treatment cycles in which the patient received u-hCG during the same period; either Profasi (Serono), Pregnyl (Organon) or Novarel (Ferring). Methods: When follicular development was deemed to be optimal on the basis of serum estradiol concentration and ovarian ultrasound, either rec-hCG (250ug sc) or u-hCG (10,000 IU im) was administered as a single dose. Efficacy was assessed as the arithmetic difference between the number of ovarian follicles (>12mm) and the number of oocytes isolated 36 hours after hCG injection, the proportion of oocytes which underwent normal fertilization following insemination and, for cases in which cumulus cells were removed prior to intracytoplasmic injection of sperm, the proportion of oocytes at metaphase II. These values were calculated for individual treatment cycles within the rec-hCG and the u-hCG groups, respectively. The statistical significance of any difference in the mean of these values for the rec-hCG and the u-hCG groups was examined using one-way ANOVA. Results: Neither the mean age at commencement of stimulation ( rec-hCG 35.8 ± 4.1, u-hCG 35.2 ± 3.9 years, p=0.07) nor the interval from hCG injection to follicular aspiration (rec-hCG 36.0 ± 4.9, u-hCG 35.9 ± 3.8 hours, p=0.803) was different between the two groups. The mean differential between the number of oocytes isolated and the number of follicles present in each patient was not different between the rec-hCG and the u-hCG cycles (rec-hCG +0.4 ±5.4, u-hCG 0.0 ±5.0 percent, p=0.330). Similarly, the mean proportion of oocytes forming two pronuclei at 16–22 hours after insemination (rec-hCG 55.8 ±23.6, u-hCG 57.9 ±24.5 percent, p=0.273) and the mean proportion of oocytes at metaphase II (rec-hCG 76.5 ± 1.9, u-hCG 77.0 ± 1.0 percent, p=0.794) were not different between rec-hCG and u-hCG cycles. Conclusion: Ovidrel (rec-hCG) is as effective as urinary hCG in the recovery of oocytes for insemination in vitro.

OBJECTIVE:To determine the presence or absence of the deleted in azoospermia (DAZ) gene clusters in the Y-bearing spermatozoa in semen of severely oligozoospermic men or in testicular biopsy samples of azoospermic men with somatic DAZ deletions.DESIGN:Prospective study.SETTING:Academic hospital.PATIENT(S):Nineteen patients attending our clinics for therapeutic intracytoplasmic injection of sperm.INTERVENTION(S):Peripheral blood lymphocytes were used to obtain somatic DNA for analysis using the polymerase chain reaction. Analysis of chromosomes X and Y and the detection of the DAZ gene clusters were carried out with the fluorescence in situ hybridization technique in spermatozoa remaining after intracytoplasmic sperm injection.MAIN OUTCOME MEASURE(S):Presence or absence of the DAZ gene clusters in matched somatic DNA and Y-bearing spermatozoa.RESULT(S):Seven patients appeared to have a somatic DAZ deletion. Three-color fluorescence in situ hybridization showed that all Y-bearing spermatozoa examined from these men carried the same deletion.CONCLUSION(S):The DAZ deletions present in the seven men would all have been transmitted if they had fathered sons through artificial fertilization techniques using the sperm cells examined in this study.

Objective: Oral contraceptive steroids (OCS's) are presently used in a significant proportion of patients to suppress ovarian activity for a specified period prior to initiating ovarian stimulation with exogenous gonadotropins. In this way, a patient's treatment can be best matched to their schedule and to the clinical resources necessary for their treatment. We observed that the period of exposure to OCS's varied considerably between patients and therefore undertook a retrospective analysis of ovarian response in patients administered OCS's immediately prior to a standardized regimen of ovarian stimulation between January 1998 and December 1999. Design: The response of the female partner to sequential OCS's, GnRH agonist and exogenous gonadotropins was analyzed for couples in which intracytoplasmic injection was to be performed because of sub-fertility in the male partner. Materials and Methods: The female partner was administered OCS's (Ortho-Novum 1/35 or Desogen) daily commencing the third day after onset of a spontaneous menstrual period for 14 to 106 days before beginning daily injections of Lupron. Suppression of pituitary gonadotropin secretion was confirmed before beginning daily injections of exogenous gonadotropins. Thereafter, ovarian response was monitored by measurement of estradiol in serum and ovarian ultrasound; an ovulatory dose of hCG was administered when the largest cohort of follicles had exceeded a diameter of 17mm. Subjects were categorized; A: 14–28 (n=249), B: 29–42 (n=218), C: 43–56 (n=121) and D: >56 days of OCS's (n=45). Analysis of variance combined with Duncan's multiple range was used to determine the statistical significance of differences between categories at the 0.05 level. Results: The mean age of all subjects was 34.1 ± 4.4 years and did not differ between groups. Compared to category A, the mean interval from first gonadotropin injection to the ovulatory dose of hCG was increased significantly (A: 10.9 < C: 11.6, D: 11.7 days) as was the total amount of gonadotropin administered (A: 31.6 < C: 43.6, D: 44.0 ampoules). Serum estradiol concentrations in the 36 hour period prior to hCG injection were decreased significantly (A: 1673 > B: 1515, C: 1419 pg/mL) as were the quotients of maximum estradiol concentration and ampoules of gonadotropin (A: 57.16 > C: 42.8 pg/mL/ampoule), the total number of oocytes isolated (A: 14.3 >B; 12.7, C: 11.9, D: 11.7 oocytes) and the number of mature (MII) oocytes available for insemination (A: 10.3 >B; 9.0, C: 8.6, D: 8.3 oocytes). Conclusion: While OCS's can be used effectively to manage patients undergoing ovarian stimulation, the subsequent ovarian response to exogenous gonadotropins is reduced significantly in patients maintained on OCS's beyond 28 days.

Testicular tissue extraction (TESE) to obtain spermatozoa for use with intracytoplasmic sperm injection (ICSI) has recently been employed in patients with non-obstructive azoospermia. Standard protocol is to retrieve a new sample of testis tissue on the day of oocyte recovery. Unfortunately, approximately 30% of men will possess no spermatozoa in their tissue, making ICSI an impossibility. We investigated whether testicular tissue that was intentionally obtained well before any planned ICSI cycle and cryopreserved could then serve as an efficacious sperm source in a subsequent ICSI cycle. This study reports on 10 men with non-obstructive azoospermia who did have spermatozoa found within their testis tissue at the time of TESE and who chose to use their frozen samples as the source of spermatozoa for a later cycle of ICSI. In 19 cycles the overall fertilization rate was 48%. Embryo transfer occurred in 89% of cycles. Two couples have achieved pregnancy (one ongoing, one delivered). All patients except one had multiple vials of frozen tissue remaining following their first cycle. This approach is offered as an alternative to repeated testicular tissue sampling, as the availability of spermatozoa is assured prior to the initiation of ovulation induction. This tissue can be harvested at the same time as diagnostic biopsy, thereby minimizing the number of surgical procedures.

SummaryThe relative level of blood flow through thecal capillaries (RTF) in individual atretic and non‐atretic follicles >1 mm was measured in conscious ewes by injecting 15 μm radioactive microspheres into the aorta near the origin of the ovarian artery, and determining the ratio of radioactivity per mg protein in theca of individual follicles to that in the non‐luteal portion (stroma plus follicles <1 mm diameter) of the corresponding ovary.In follicles >1 mm diameter, RTF in those showing advanced stages of atresia (stages IV and V) was significantly less than that in non‐atretic (stage I) follicles. RTF values in non‐atretic (stage I), early atretic (stage II) and moderately atretic (stage III) follicles did not differ significantly. There was no effect of follicular diameter (P>0·05) on the relative level of blood flow within individual thecae or of atresia on thecal protein content.These data indicate that reduced thecal blood flow is associated with advanced atresia of antral follicles and are in accordance with the findings of previous histological studies. Whether thecal ischaemia is a factor involved in the onset of atresia, or occurs as a consequence of the degenerative process, remains uncertain.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnthalpy of formation of acyl-, alkyl- and hydridopentacarbonyl-manganese complexes. The enthalpy contributions of manganese-hydrogen and manganese-carbon bonds in these molecules. Thermochemical aspects of models in Fischer-Tropsch reactionsJoseph A. Connor, Mohamed T. Zafarani-Moattar, James Bickerton, Nabila I. El Saied, Sukiman Suradi, Ronald Carson, Ghassan Al Takhin, and Henry A. SkinnerCite this: Organometallics 1982, 1, 9, 1166–1174Publication Date (Print):September 1, 1982Publication History Published online1 May 2002Published inissue 1 September 1982https://doi.org/10.1021/om00069a011RIGHTS & PERMISSIONSArticle Views312Altmetric-Citations91LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts