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Biomedical subjects

A S Penzias

Publications and source records attributed to A S Penzias.

At least 19 recordsLinked to original sources
PubMed2004

Improving results with assisted reproductive technologies: individualized patient-tailored strategies for ovulation induction.

Infertility treatment should be made as efficacious as possible while being simple for patients. Although the treatment paradigm may be, at times, complex, patients deserve pure products that simplify protocol implementation while providing reliable outcomes. The more the treatment experience is simplified and improved, the more patients will benefit from the technology.

Female↗
PubMed2000

Infertility. Contemporary office-based evaluation and treatment.

Infertility is a common condition that is highly treatable. Couples can help themselves by recognizing that they have a problem, and practitioners can help patients by recognizing who requires an infertility investigation and when they need it. Instituting a clear and comprehensive evaluation will enable patients who need treatment to achieve their goals.

Adult↗
PubMed1999

Administration of progesterone before oocyte retrieval negatively affects the implantation rate.

OBJECTIVE: To compare the efficacy of two clinically accepted methods of progesterone supplementation during IVF. DESIGN: Prospective randomized trial. SETTING: A university-based IVF program. PATIENT(S): Three hundred fourteen stimulated IVF cycles between January 1993 and October 1994. INTERVENTION(S): Patients were assigned to one of two luteal phase progesterone regimens by a random permuted block design. In protocol A, 12.5 mg of IM progesterone was given 12 hours before oocyte retrieval; in protocol B, 25 mg of IM progesterone was given on the day of oocyte retrieval. MAIN OUTCOME MEASURE(S): Clinical pregnancy. RESULT(S): Patient demographic characteristics, including age, diagnosis, number of oocytes retrieved and fertilized, and number of embryos transferred, were not different between the two groups. There was no difference in the rate of cycle cancellation between the groups. One hundred forty ETs were performed in patients assigned to protocol A and 142 in patients assigned to protocol B. The clinical pregnancy rate in group A was 12.9% compared with 24.6% in group B. CONCLUSION(S): The administration of progesterone before oocyte retrieval is associated with a lower pregnancy rate than the administration of progesterone after oocyte retrieval.

Adult↗
PubMed1998

Technical and physiological aspects associated with the lower fertilization following intra cytoplasmic sperm injection (ICSI) in human.

The fertilization rates with ICSI range from 30% to 70% and suggest that, despite injecting sperm into mature oocytes, significant fertilization failure still occurs in humans. The objective of this study was to determine technical and physiological factors which may contribute to lower fertilization following ICSI. Eggs that failed to show two pronuclei (PN) 48 hours after ICSI were studied at two different time intervals: at ICSI program inception (group A) and after 8 months (group B). The eggs were analyzed by staining with DNA fluorochromes, Hoescht 33258 and DAPI. The extent of sperm head as well as maternal chromatin decondensation in unfertilized ICSI eggs was determined by high resolution fluorescence microscopy. The average fertilization rate (FR) from all ICSI cycles in these two groups was 45%. The FR in Groups A and B were 35% and 59%, respectively (P < 0.05). In Group A, 65% of the unfertilized eggs were characterized by condensed sperm chromatin with 11% showing partial decondensation. In Group B, only 28% of the unfertilized eggs demonstrated condensed sperm chromatin while 45% were partially decondensed. Sperm chromatin was not detected in 24% of all unfertilized eggs studied. The maternal chromatin remained at metaphase II in 84% of all unfertilized eggs analyzed. These observations suggest that the technical problem of deposition of the sperm inside the egg is not the major cause for failure of fertilization rates in ICSI cycles. The increased percentage of eggs undergoing sperm head decondensation may be related to subtle changes in technique as experience is gained over time. The failure of sperm head decondensation in some of the ICSI eggs may be associated with cytoplasmic immaturity but not nuclear maturity.

Chromatin↗
PubMed1998

Neonatal morbidity and mortality associated with triplet pregnancy.

OBJECTIVE: To compare neonatal morbidity and mortality in a large cohort of triplet pregnancies with singleton and twin neonates managed at a single tertiary center over a short time. METHODS: Records from all triplet pregnancies managed and delivered from 1992 to 1996 were reviewed for neonatal outcome data. Pregnancies delivered before 20 weeks' gestation and neonates with lethal congenital anomalies were excluded. The comparison group comprised all singleton and twin neonates managed in the same neonatal intensive care unit (NICU) during the same period. RESULTS: During the 5-year period, 55 triplet pregnancies and their resulting 165 neonates were managed and delivered at this center. Their outcomes were compared with those of 959 singleton and 357 twin neonates born at similar gestational ages. The median gestational age at delivery for triplets was 32.1 weeks, and 149 of the 165 infants were admitted. Sixteen triplet neonates were not admitted to our neonatal intensive care unit, 12 because of previable gestational age, three because of stillbirth, and one because of a lethal congenital anomaly. The crude perinatal mortality rate in triplets was 121 per 1000 births, and there was no significant difference in outcome based on triplet birth order. There were no significant differences in survival rates between singleton, twin, and triplet neonates, with an overall neonatal survival of 95%, 95%, and 97%, respectively. The only significant differences in morbidity were an increased incidence of mild intraventricular hemorrhage (relative risk [RR] 6.20; 95% confidence interval [CI] 2.64, 14.61), mild retinopathy of prematurity (RR 20.05; 95% CI 3.59, 111.79), and severe retinopathy of prematurity (RR 46.69; 95% CI 6.25, 348.85) in triplets compared with singletons, and severe retinopathy of prematurity (RR 6.83; 95% CI 1.24, 37.56) in triplets compared with twins. CONCLUSION: When stratified by gestational age, triplet neonates delivered at 24-34 weeks' gestation have similar outcomes as singleton and twin neonates, with the only clinically significant difference being an increased incidence of retinopathy of prematurity in triplets.

Female↗
PubMed1997

Failed fertilization after intracytoplasmic sperm injection: the extent of paternal and maternal chromatin decondensation.

OBJECTIVE: To determine the extent of paternal and maternal chromatin decondensation in unfertilized eggs after intracytoplasmic sperm injection (ICSI). DESIGN: Eggs that failed to show two pronuclei (2-PN) 48 hours after ICSI were studied at two different time intervals: at ICSI program inception (group A) and after 8 months (group B). PATIENT(S): Forty-nine patients undergoing IVF cycles. MAIN OUTCOME MEASURE(S): The unfertilized eggs were studied by chromatin staining. RESULT(S): The average fertilization rate from all ICSI cycles in these two groups was 45%. The fertilization rates in groups A and B were 35% and 59%, respectively. In group A, 65% of the unfertilized eggs were characterized by condensed sperm chromatin with 11% showing partial decondensation. In group B, only 28% of the unfertilized eggs demonstrated condensed sperm chromatin, whereas 45% were partially decondensed. In these two groups, no sperm chromatin was detected in 24% of the unfertilized eggs. The maternal chromatin remained at metaphase II in 84% of all unfertilized eggs analyzed. CONCLUSION(S): These observations suggest that the technical problem of deposition of the sperm inside the egg is not the major cause of failure of fertilization rates in ICSI cycles. Rather, it is likely to be the failure to complete both the maternal and paternal chromatin transitions that occur with normal fertilization.

Chromatin↗
PubMed1996

Biochemical study of individual zonae from human oocytes that failed to undergo fertilization in intracytoplasmic sperm injection.

Successful intracytoplasmic sperm injection (ICSI) is dependent upon the competence of the oocyte to respond to the injection of a spermatozoon in the presence of calcium. This study determined if oocytes that failed to become fertilized (absence of any pronuclei) failed to undergo cytoplasmic activation, as ascertained by an electrophoretic shift in the zona pellucida (zona) protein, huZP2. Of 48 zonae individually analysed, 58% did not have a detectable huZP2 shift. Three patterns were observed. In seven patients, none of the unfertilized oocyte huZP2 shifted (16 out of 48); in two, all zonae exhibited a huZP2 shift (five out of 48); in eight, there was a mixture of shifted and unshifted (27 out of 48) in each case. There was no clear relationship between the presence of the huZP2 shift and maternal age, pregnancy outcome, male-factor infertility, or fertilization rate. However, in six couples diagnosed as having no detectable male-factor infertility, 73% (11 out of 15) of the zonae had unshifted huZP2, suggesting that an oocyte defect is involved in some cases of failed fertilization after ICSI. One likely cause for the absence of the huZP2 shift is a failure of cytoplasmic activation. Since oocytes were injected at metaphase II, we hypothesize that some oocytes that failed to fertilize have completed nuclear (meiotic) without cytoplasmic maturation.

Adult↗
PubMed1995

Costs of triplet pregnancy.

OBJECTIVE: Our purpose was to describe the total costs involved in the delivery, prenatal, and neonatal care for triplet pregnancies. STUDY DESIGN: Twenty triplet pregnancies were born at our institution over the 1-year period between July 1, 1992, and June 30, 1993. Total charges for prenatal care, physician fees, antepartum admissions, delivery, postpartum inpatient and outpatient care, and neonatal inpatient and outpatient care were extracted from the hospital billing computers. RESULTS: Our 20 triplet pregnancies were delivered of 54 live born infants at an average gestation of 30.2 weeks. Mothers averaged 16.7 inpatient hospital days. Total cost of prenatal care, outpatient laboratories and ultrasonography, delivery, and maternal inpatient care averaged $27,491. Neonates averaged 13.7 hospital days. Total neonatal costs for the inpatient stay and short term-postpartum (< 6 week) outpatient period was $36,856 per family. Total average cost per family was $64,347. CONCLUSION: Combined maternal and neonatal costs per individual baby delivered was approximately $21,000. Although expensive, this cost is far from prohibitive, even in times of close attention to health care expenditures.

Boston↗
PubMed1995

The correlation between follicular measurements, oocyte morphology, and fertilization rates in an in vitro fertilization program.

OBJECTIVE: To explore the relationship between follicle size and the morphology of the oocyte-cumulus-corona complex with fertilization rates in stimulated cycles of IVF. DESIGN: Retrospective comparison of measurements and observations of 2,429 oocytes from 215 patients undergoing 324 stimulated IVF cycles. SETTING: A large hospital-based IVF program. MAIN OUTCOME MEASURES: Individual follicles were measured by ultrasound before transvaginal aspiration and the size was recorded. The oocyte-cumulus-corona complex from each follicle was examined and classified. The oocytes were checked for evidence of fertilization 17 to 22 hours after insemination. RESULTS: The fertilization rate of all oocytes regardless of morphological type revealed a positive linear correlation with increasing follicle diameter. The fertilization rates of type I oocytes was marginally higher than type II oocytes, controlling for follicle diameter; however, this difference did not achieve statistical significance. Oocytes from follicles with a mean diameter > or = 16 mm had significantly higher fertilization rates than did oocytes from follicles with a mean diameter < or = 14 mm. CONCLUSIONS: Follicle size is a better predictor of fertilization than is morphological characterization of the oocyte-cumulus-corona complex in IVF.

Female↗
PubMed1995

A zona biochemical change and spontaneous cortical granule loss in eggs that fail to fertilize in in vitro fertilization.

OBJECTIVE: To determine the extent of biochemical changes in the zona pellucida (ZP) and cortical granule release in eggs failing to fertilize in IVF. DESIGN: After insemination, unactivated eggs without two pronuclei (PN) were studied by high resolution microscopy and fluorescent probes to determine cortical granule density and meiotic stage. After ZP isolation, proteins from individual ZPs were biotinylated, electrophoresed, and visualized by western blots with avidin-chemiluminescence. Controls included mouse unfertilized and fertilized eggs and human germinal vesicle stage oocytes and > or = 3PN eggs. SETTING: University medical center and hospital tertiary care IVF-ET program. RESULTS: Many of the unfertilized eggs were in metaphase and had relatively low cortical granule densities indicative of cortical granule loss. Approximately one half of the ZPs showed evidence of biochemical hardening with a modification of a 90 to 100 x 10(3) molecular (weight) ratio (M(r)) ZP protein. The 3PN eggs had few cortical granules and their ZPs had a pronounced 90 to 100 x 10(3) M(r) modification that was not detected in germinal vesicle stage ZP controls. CONCLUSION: The observed changes in ZP biochemistry and cortical granule quantitation demonstrate that failed fertilization is frequently associated with spontaneous cytoplasmic, but not nuclear, activation. In affected eggs, these changes could prevent fertilization in routine IVF and in cases of reinsemination. The relationship of changes in the ZP and cortical granules to infertility and in vitro culture requires further investigation. The 90 to 100 x 10(3) M(r) ZP protein modification can be detected biochemically with 1/10 of a human ZP.

Animals↗
PubMed1995

The effect of Norplant on glucose metabolism under hyperglycemic hyperinsulinemic conditions.

OBJECTIVES: To assess the impact of a levonorgestrel-releasing implant contraceptive (Norplant; Wyeth-Ayerst Laboratories, Philadelphia, PA) on glucose metabolism. DESIGN: Prospective evaluation of insulin action and secretion in women under hyperglycemic hyperinsulinemic clamp conditions in the midfollicular phase before and 8 weeks after Norplant placement. SETTING: Yale University Clinical Research Center. PARTICIPANTS: Seven previously normally cycling, nonobese, nondiabetic women participated in the study. INTERVENTIONS: Norplant insertion. MAIN OUTCOME MEASURES: Basal levels of glucose and insulin, as well as glucose-mediated insulin secretion, glucose uptake, and tissue sensitivity to insulin were assessed using the hyperglycemic hyperinsulinemic clamp technique before and after Norplant insertion. RESULTS: Norplant placement did not alter the fasting glucose or insulin levels. However, it was associated with a significant 37% increase in the first phase insulin response from a control level of 51 +/- 8 to 70 +/- 10 microU/mL (conversion factor to SI unit, 7.175), and a significant 48% increase in the second phase insulin response from 60 +/- 5 to 89 +/- 8 microU/mL. In association with this increase in insulin levels after Norplant insertion, total mean body glucose uptake (M) increased from 8.08 +/- 0.91 to 9.53 +/- 0.95 mg/kg per minute. However, when expressed as the total body glucose uptake per unit of insulin, the M:I ratio (a measure of tissue sensitivity to insulin) decreased significantly from a mean of 0.12 +/- 0.02 to 0.10 +/- 0.01 mg/kg per minute per microU/mL. CONCLUSION: Although Norplant insertion does not alter basal glucose and insulin levels, tissue sensitivity to insulin under hyperglycemic hyperinsulinemic conditions is decreased after Norplant insertion.

Adult↗
PubMed1994

Aberrant estradiol flare despite gonadotropin-releasing hormone-agonist-induced suppression is associated with impaired implantation.

Our results confirm the previous report that rapid suppression by GnRH-a is favorable relative to delayed suppression (1). They further indicate that the pattern of E2 production during GnRH-a-induced ovarian suppression may be predictive of cycle outcome. We suggest that imperfect pituitary suppression of bioactive LH as indicated by an aberrant rise in E2 during GnRH-a down-regulation may compromise oocyte quality and ultimately impair implantation. Further study of follicular phase E2 response to GnRH-a suppression may provide a prognostic marker for implantation.

Embryo Implantation↗
PubMed1994

Laparoscopic diagnosis and methotrexate treatment of an ovarian pregnancy: a case report.

This report suggests an alternative for dealing with the diagnostic dilemma of differentiating an ovarian pregnancy from a ruptured CL cyst and suggests a conservative management approach that will possibly minimize adhesion formation and optimize future fertility. This new approach is based on a single case reported here, and therefore needs further verification. However, use of this revised set of diagnostic criteria, combined with the judicious use of MTX, may be an alternative therapy for selected ovarian pregnancies.

Adult↗
PubMed1994

Ultrasound prediction of follicle volume: is the mean diameter reflective?

OBJECTIVE: To evaluate the relationship between 2 dimensional sonographic measurement of ovarian follicles and their actual volume. DESIGN: Prospective clinical study. SETTING: The in vitro fertilization (IVF) program of a University based, tertiary care hospital. PATIENTS AND INTERVENTIONS: Sonographic categorization by shape, and measurement of 96 individual ovarian follicles immediately prior to aspiration for IVF. Each follicle was aspirated under direct ultrasound guidance and the volume recorded. The 96 follicles were visualized in a total of 14 patients from whom 2 to 27 oocytes were obtained. MAIN OUTCOME MEASURE: Total volume of each follicle. RESULTS: Round and polygonal follicles exhibited a highly significant relationship between sonographically measured mean diameter and total follicle volume. The volume of follicles that were categorized as ellipsoid was not predicted by measurement of the longest diameter, shortest diameter or mean diameter. CONCLUSION: The mean diameter of round and polygonal follicles accurately predicts total follicular volume. However, clinical decisions in ovulation induction should be modified when the follicle shape is predominantly ellipsoid because the traditionally held belief that the sonographic measurement of the follicular diameter correlates with the follicular volume does not apply in those circumstances.

Female↗
PubMed1993

Proliferative index of human luteinized granulosa cells varies as a function of ovarian reserve.

OBJECTIVE: We examined whether the proliferative index of luteinized granulosa cells, as determined by flow cytometry, varied as a function of a woman's ovarian reserve, as reserve, as reflected by follicular-phase day 3 serum follicle-stimulating hormone. STUDY DESIGN: This prospective cohort study consisted of 19 women of similar chronologic age preparing for in vitro fertilization-embryo who met specific day 3 serum follicle-stimulating hormone criteria. The "low follicle-stimulating hormone" group consisted of 11 women with day 3 serum follicle-stimulating hormone levels < or = 6 IU/L. The "high follicle-stimulating hormone" group consisted of eight women with day 3 serum follicle-stimulating hormone levels > or = 18 IU/L. A total of 56 preovulatory follicles containing > or = 10(4) luteinized granulosa cells were examined by flow cytometry. The low follicle-stimulating hormone group was compared with the high follicle-stimulating hormone group to examine proliferative index as a function of serum day 3 follicle-stimulating hormone levels. RESULTS: The low follicle-stimulating hormone group had a greater proliferative index (11.1% +/- 0.4%) than did the high follicle-stimulating hormone group (8.3% +/- 0.6%), p < 0.001). This study demonstrates that in spite of the same chronologic age, luteinized granulosa cells from preovulatory follicles of women with day 3 serum follicle-stimulating hormone levels > or = 18 IU/L have a 25% decreased proliferative index compared with luteinized granulosa cells from women with day 3 serum follicle-stimulating hormone levels < or = 6. CONCLUSIONS: This suggests that granulosa cell proliferation is influenced by ovarian reserve and may explain in part the more favorable response to ovulation induction protocols that younger women demonstrate compared with women of more advanced reproductive age.

Adult↗
PubMed1993

Dichloroacetic acid accelerates initial development of 2-cell murine embryos in vitro.

Preimplantation embryos up to the 8-cell stage of development use lactate and pyruvate but not glucose or Krebs cycle intermediates to support growth, development, and cleavage. The dominant effect of dichloroacetic acid (DCA) is the irreversible stimulation of pyruvate dehydrogenase (PDH) activity, thus accelerating the oxidative metabolism of pyruvate and lactate. To test the hypothesis that early induction of oxidative metabolism in 2-cell murine embryos accelerates preimplantation embryo cleavage rates, female B6C3F1 mice at 6 to 8 weeks of age were superovulated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) and mated. All 2-cell stage embryos were randomly assigned to culture media with or without 130 micrograms/mL DCA. The developmental stage of all embryos was then noted every 24 hours for a total of 72 hours. Chi-square analysis and the method of average rank sum were used to compare the distribution of embryos at each observation point. At 24 hours, DCA-exposed embryos had achieved an advanced stage of growth and development relative to controls (average rank sum, P = .026; chi-square distribution, P = .047). Subsequently, at 48 and 72 hours, neither the average rank sum nor the chi-square distribution was different. Our data suggest that DCA accelerates early growth and development of murine embryos before implantation, possibly through the early induction of oxidative metabolism.

Animals↗