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Biomedical subjects

R F Casper

Publications and source records attributed to R F Casper.

At least 73 records · Page 4Linked to original sources
PubMed1995

Type of stimulation protocol affects oocyte maturity, fertilization rate, and cleavage rate after intracytoplasmic sperm injection.

OBJECTIVE: To compare oocyte maturity, fertilization rate and cleavage rate after a short and long GnRH agonist (GnRH-a) stimulation protocol and intracytoplasmic sperm injection (ICSI). DESIGN: Retrospective study of 34 sequential ICSI cycles stimulated with a short or long GnRH-a protocol. SETTING: A university-based tertiary care center for assisted reproductive treatment. RESULTS: Significantly more oocytes were mature (metaphase II) after a long GnRH-a protocol then after a short GnRH-a protocol (25.6% and 80.8%, respectively). The long protocol resulted in more cleaving embryos (36/152 versus 9/132) and more cycles of ET (12/17 versus 5/17) than the short group. CONCLUSION: A greater percentage of mature oocytes results from ovarian stimulation with a long GnRH-a protocol than a short GnRH-a protocol. Maturity could be assessed accurately after cumulus stripping that is required before ICSI. Fertilization rate and cleavage rate with ICSI was superior after a long GnRH-a stimulation protocol for superovulation.

Adult↗
PubMed1995

Cadmium accumulation in follicular fluid of women in in vitro fertilization-embryo transfer is higher in smokers.

OBJECTIVE: To assess cadmium, a heavy metal in cigarette tobacco, in follicular fluid (FF) of women in IVF-ET, who smoke. DESIGN: Controlled clinical study. SETTING: Infertile patients in a hospital IVF-ET program. PATIENTS: Fifty-one women selected in groups according to smoking habits: nonsmokers (n = 10), passive smokers (n = 17), light smokers (< 15 cigarettes per day, n = 19), and heavy smokers (> or = 15 cigarettes per day, n = 5). INTERVENTIONS: Ovarian hyperstimulation with GnRH agonist. RESULTS: The mean +/- SEM level of FF cadmium was higher in smokers (7.93 +/- 0.16 ng/mL) than in nonsmokers (6.73 +/- 0.31 ng/mL), and with a dose-effect of smoking. The individual levels in passive, light, and heavy smoking women also were higher than in nonsmoking women. CONCLUSIONS: Despite lack of vascularization of the follicle, cadmium accumulation was detectable in FF. Cadmium also could accumulate in oocytes of smokers; it does so, in a dose-dependent manner, in oocytes of cadmium-treated rats. Access to cadmium and other contaminants of cigarette smoke in FF may compromise the quality of oocytes, becoming a risk factor.

Adult↗
PubMed1995

Involvement of programmed cell death in preimplantation embryo demise.

Fragmentation is frequently observed in animal and human embryos obtained via in-vitro fertilization (IVF), and is known to be associated with decreased pregnancy rates and poor survival following cryopreservation. We postulate that embryo fragmentation is a consequence of activated programmed cell death (PCD) and subsequent apoptosis and discuss evidence of morphological, histological and biochemical features compatible with the occurrence of PCD in preimplantation embryos. If PCD is an underlying cause of the high incidence of the fragmentation seen in human pre-embryos, it remains to be determined whether this is reflective of the natural incidence of lethal chromosomes in the human population or due to the IVF procedure and culture conditions.

Animals↗
PubMed1995

Cigarette smoking may affect meiotic maturation of human oocytes.

There is a strong association between cigarette smoking and reduced fecundity, reduced fertility, and early mean age of menopause, suggesting that smoking may impair oocyte function and viability. We analysed the effect of smoking on meiotic maturation of oocytes. A total of 156 women undergoing in-vitro fertilization therapy, classified as non-smokers (n = 102), passive smokers (n = 21), light smokers (< 15 cigarettes/day; n = 19), and heavy smokers (> or = 15 cigarettes/day, n = 14), participated in this study. Tubal factor infertility was more frequent in smokers, in agreement with the literature, and showed a significant dose effect (P = 0.008). Smokers had decreased numbers of retrieved oocytes compared with non-smokers, suggesting reduced fertility. Cytogenetic data from 286 oocytes apparently unfertilized showed similar proportions of haploid (normal) and aneuploid chromosome complements among groups. In contrast, oocytes with diploid complements were more frequent among smokers. Regression of individual proportions of diploid oocytes on number of cigarettes smoked per day was very significant (P = 0.0003). The increased frequency of oocyte diploidy in smokers, probably resulting from prevention of first polar body extrusion, indicates meiotic immaturity. Also, triploid zygotes occurred more frequently in smokers (P = 0.03), suggesting preferential digynic fertilization. Our study shows that external factors, like cigarette smoking, may be hazardous to the viability and function of developing oocytes and their resulting embryos.

Adult↗
PubMed1995

Discrimination against men in infertility treatment.

OBJECTIVE: To evaluate the scope of the medical effort invested in the study and treatment of male infertility, some of its sources and implications. STUDY DESIGN: The study reviewed the range of medical treatments of male and female infertility and their effectiveness. It also examined the funding policy in Ontario, Canada, as well as patients' responses to this policy. RESULTS: Male infertility therapy is relatively lacking and is not funded by the Ontario Health Insurance Plan. Neither professionals nor patients, however, challenge the unequal policy. CONCLUSION: The traditional association of infertility with the female partner prevails among professionals, policy makers and patients. It explains both the relative lack of therapy and the absence of public resentment. This traditional attitude hinders the prospects that infertile men will be assisted by biomedicine.

Female↗
PubMed1995

Recombinant human leukemia inhibitory factor does not enhance in vitro human blastocyst formation.

OBJECTIVE: To assess the effect of human recombinant leukemia inhibitory factor in different doses on human blastocyst formation. SETTING: A university-based tertiary referral center (The Toronto Hospital). INTERVENTIONS: Nontransferable human embryos (n = 473) at the two- to six-cell stage were obtained from patients undergoing IVF and were split randomly into five groups. Embryos in group A (n = 164) were cultured as the control group in Ham's F-10 (GIBCO-BRL, Grand Island, NY) + 10% human sera. Embryos in groups B, C, D, and E (n = 54, 78, 87, and 80, respectively) were cultured in the same medium supplemented with human recombinant leukemia inhibitory factor in four different concentrations (5, 7.5, 10, and 20 ng/mL, respectively). Morphological assessment of embryo development was recorded daily. MAIN OUTCOME MEASURE: Human blastocyst formation. RESULTS: No significant difference was detected in the rate of blastocyst formation of embryos in the study groups when compared with embryos in group A. CONCLUSIONS: This study shows that 5 to 20 ng/mL of recombinant leukemia inhibitory factor in standard medium does not enhance in vitro human blastocyst formation. It is possible that recombinant leukemia inhibitory factor may play a role at later stages of human embryogenesis and during implantation.

Blastocyst↗
PubMed1995

Hyaluronidase activity in human semen: correlation with fertilization in vitro.

OBJECTIVES: To characterize the relationship between hyaluronidase activity and the currently used methods of assessing sperm function and to determine whether the measurement of hyaluronidase activity can provide a reliable index of sperm fertilizing capacity in man. DESIGN: Nonrandomized prospective study. SETTING: Tertiary referral IVF and andrology clinics affiliated with the University of Toronto. SUBJECTS: Four hundred eight samples were collected, 248 from men undergoing investigation in andrology and fertility clinics and 160 from men participating in an IVF program. INTERVENTIONS: Semen samples were treated with NP-40 in buffer to extract hyaluronidase and applied to a circular well cut into a petri dish containing a mixture of hyaluronic acid and agar. Enzyme activity was assessed by measuring the area of substrate hydrolysis. RESULTS: Significant positive correlations were found between hyaluronidase activity and sperm concentration, motility, and the percentage of sperm with normal morphology in the studied samples. In the IVF samples, hyaluronidase activity was found to be related significantly to the fertilization rate. Moreover, we were able to establish values of hyaluronidase below which no fertilization occurred and above which fertilization of at least one oocyte was achieved. CONCLUSION: These results suggest that measurement of hyaluronidase activity may provide a useful method for assessing the integrity of the acrosomal enzyme system, providing a simple and reliable predictor of the fertilizing potential of human sperm.

Enzyme Stability↗
PubMed1995

The effect of three hormone replacement regimens on bone density in the aged ovariectomized rat.

OBJECTIVE: To investigate the effects of estrogen (E) alone or with cyclic, continuous, or interrupted P regimens on bone density in an aged rat model. DESIGN: Randomized controlled trial. ANIMALS: Twenty 12-month-old female Sprague-Dawley rats were sham operated (intact control) and 100 were ovariectomized (OVX). INTERVENTION: Four groups of 20 OVX rats were implanted with silastic capsules containing 5% E2 (wt/wt) in cholesterol. All rats in the intact control (group 1), OVX (group 2), and the first of the OVX plus E groups (group 3) were injected subcutaneously daily for 6 months with corn oil (vehicle). Three other groups of rats with E capsules received daily injections of norethindrone in corn oil, according to the following dosage schedules: 6 micrograms norethindrone/rat per day for 2 of every 4 weeks (cyclic; group 4); 3 micrograms norethindrone/rat per day every day (continuous; group 5); or 3 micrograms norethindrone/rat per day for 3 of every 6 days (interrupted; group 6). MAIN OUTCOME MEASURES: Bone mineral content (BMC) and bone mineral density (BMD) in the femur and vertebrae were measured by dual-energy roentgenogram absorptiometry. RESULTS: The OVX rats (group 2) receiving corn oil alone had the lowest BMD. Intact controls (group 1), E plus cyclic P (group 4), and E and interrupted P (group 6) were all similar and had significantly greater bone density in the vertebrae than the OVX controls. In contrast, vertebral BMD with E alone (group 3) and continuous E and P (group 5) was not significantly different from the OVX group. Femur BMD was significantly lower in the OVX group compared with the other five groups, which did not differ significantly from each other. CONCLUSION: In this experimental model, compared with OVX controls, combined hormone replacement therapy with E and cyclic or interrupted P resulted in the best vertebral BMD whereas continuous E and P resulted in the worst BMD. In the femurs, E alone and E plus P had equal effects on BMD.

Adrenal Glands↗
PubMed1994

Preliminary characterization of a factor in human follicular fluid that stimulates human spermatozoa motion.

Follicular fluid alters the physiology and behaviour of spermatozoa by increasing acrosome reaction, accelerating capacitation, attracting the spermatozoon and enhancing vigorous motion of the cell. The objective of this study was to characterize the factor(s) in human follicular fluid that causes vigorous spermatozoa motion. Follicular fluid and its fractions were tested for stimulation of spermatozoa motion using a standardized assay which employs a computerized digital imaging system. Our results show that both follicular fluid and its methanol extract stimulate vigorous spermatozoa motion. To determine the characteristics of the active factor(s), the methanol extract was subjected to molecular weight fractionation, protease digestion, microcrystalline thin-layer chromatography (TLC) and C18 reverse-phase high-pressure liquid chromatography (HPLC). The spermatozoa motion stimulator in the methanol extract was dialysable against a low molecular weight membrane (1000 Da), insensitive to boiling and low pH (3.5) and was largely inactivated by proteinase K digestion. The activity was detected near the solvent front on TLC. Using reverse-phase HPLC monitored at 254 nm (UV), the activity eluted as a single peak of activity at low methanol concentration, indicating that the activity was relatively hydrophilic. The activity in the HPLC peak lost most of its motion-stimulating ability after digestion with proteinase K. The motion stimulator could be a peptide analogous to the egg-associated peptides characterized in echinoderms which stimulate spermatozoa motion, respiration and chemotaxis.

Chemical Fractionation↗
PubMed1994

Conditioned medium from human cumulus oophorus cells stimulates human sperm velocity.

The objective of this study was to determine whether the cumulus oophorus cells surrounding the human oocyte release a factor(s) that stimulates sperm velocity. Medium from in vitro fertilization (IVF) that was exposed to cumulus/oocyte complexes was tested for its ability to stimulate sperm velocity by use of a computerized sperm motion analyzer. In subsequent experiments, primary cultures of cumulus cells, granulosa cells, and ovarian cancer cells were established, and conditioned medium from these cells was assessed for sperm velocity-stimulating activity. In the initial series of assays using four sperm donors, cumulus/oocyte complex-conditioned medium from IVF increased sperm curvilinear velocity and amplitude of lateral head displacement by an average of 12.3% and 19.3% (p < 0.0001), respectively, compared to medium from IVF that was not exposed to cumulus/oocyte complexes. These results were confirmed in a subsequent, more extensive series of assays using a single sperm donor. Testing of conditioned media after 24 h of primary cell culture showed that cumulus-conditioned medium consistently stimulated curvilinear velocity (8.8% increase) and lateral head amplitude (18.7% increase) compared to unconditioned medium (p < 0.0001) in a manner similar to cumulus/oocyte complex-conditioned medium. In contrast, granulosa-conditioned medium and ovarian cancer cell-conditioned medium did not stimulate curvilinear velocity and lateral head amplitude compared to unconditioned medium. The ability of cumulus-conditioned medium to stimulate curvilinear velocity and lateral head amplitude declined gradually during the 5-day culture period. Nevertheless, the results indicate that the cumulus released velocity-stimulating activity throughout the culture period.(ABSTRACT TRUNCATED AT 250 WORDS)

Culture Media, Conditioned↗
PubMed1993

Estrogen and interrupted progestin: a new concept for menopausal hormone replacement therapy.

OBJECTIVE: We tested a new hormone replacement formulation based on the hypothesis that interrupted administration of progestin in the presence of continuous estrogen would result in receptor up-regulation and resensitization of target tissues to both estrogen and progestin. As a result, symptom control might be possible with lower doses of steroids and in the absence of withdrawal bleeding. STUDY DESIGN: Forty postmenopausal women were entered in a 6-month pilot study, including an 18-month extension. They received piperazine estrone sulfate 0.75 mg daily. Norethindrone 0.35 mg daily was added in 3-day phases, alternating with progestin-free phases of 3 days. There was no steroid-free withdrawal period. We examined symptom control, bleeding patterns, endometrial protection, and lipid profiles in the women over the 24 months of the study. RESULTS: Hot flushes were completely eliminated in 76% of women, and 80% had no bleeding by 6 months. There were three dropouts. Thirty-three women elected to continue after the first 6 months and completed 24 months on therapy for a compliance rate of 82.5%. No endometrial hyperplasia was seen on serial biopsies, and no changes occurred in lipids except for a small but statistically significant decrease in high-density lipoproteins and triglycerides at 24 months. CONCLUSION: Our preliminary results of low bleeding rates, good symptom control, and endometrial protection suggest that hormone replacement with low-dose estrogen and interrupted progestin is effective and may lead to improved compliance in menopausal women.

Adult↗
PubMed1993

Characterization of the first cell cycle in human zygotes: implications for cryopreservation.

OBJECTIVE: To study the temporal pattern of deoxyribonucleic acid (DNA) synthesis leading up to the first mitotic division in human one-cell stage zygotes. SETTING: In vitro fertilization program of a university hospital. PATIENTS: Couples donating spare embryos before the existence of an embryo freezing program. DESIGN: Incorporation of 3H-thymidine was examined between 9 to 27 hours after insemination in 72 untransferred human zygotes containing two pronuclei. Microscopic observations on an additional 978 transferred zygotes extended the 3H-thymidine incorporation data. RESULTS: The first thymidine incorporation was seen 9 to 10 hours after insemination, and the heaviest incorporation occurred between 11 and 13 hours. Subsequently, thymidine labeling declined, and chromosomal condensation and cell division first occurred approximately 19 to 20 hours. At 20 hours after insemination, 89% of the zygotes had two visible pronuclei (PN). In contrast, by 24 hours, 41% had no visible PN, whereas 5% had cleaved to the two-cell stage. By 27 hours, 38% had cleaved to the two-cell stage, and only 25% still had two visible PN. CONCLUSIONS: These results suggest that the DNA-synthetic, S-phase of the human zygote is initiated by approximately 9 to 10 hours after insemination and is completed approximately 3 to 5 hours later. The duration of G2 phase and mitosis is in the range of 4 to 6 and 3 to 3.5 hours, respectively. Because zygotes may be particularly susceptible to damage during the S phase of the cell cycle, these findings suggest that the optimal time for freezing of human zygotes may be approximately 20 to 22 hours after insemination when the majority of zygotes should have entered the G2 phase, before pronuclear dissolution and chromosome condensation.

Adult↗
PubMed1993

The use of vaginal ultrasound for monitoring endometrial preparation in a donor oocyte program.

OBJECTIVE: To determine whether vaginal sonographic measurements can be used to monitor the endometrial preparation of recipients in a donor egg program. DESIGN: Prospective clinical trial. SETTING: University hospital-based IVF and donor egg program. PATIENTS: Twelve women without ovarian function. INTERVENTIONS: [1] In a control cycle, patients received 4 or 8 mg of oral E2 and vaginal ultrasound (US) daily until endometrial thickness > or = 6 mm with a triple-line pattern (favorable endometrium) was seen. Progesterone (P) in oil, 100 mg/d, was then added. [2] An endometrial biopsy was performed on day 7 of P therapy. [3] In a treatment cycle, US monitoring of endometrial development during estrogen (E) administration was used; and ET was performed on the 3rd day of P therapy. RESULTS: In the control cycle, 8 mg/d or 4 mg/d of micronized E2 resulted in favorable endometrium development in all patients in a mean time of 5 and 7 days, respectively. After P treatment, only 1 of 12 endometrial biopsies was in phase. In the treatment cycles, the overall clinical pregnancy rate (PR) was 42%. In those patients with a favorable endometrium in the E replacement phase, before addition of P, the PR was 62.5%. All of the pregnant patients but only 42.8% of the nonpregnant patients had a favorable endometrium on US before the addition of P. CONCLUSION: An endometrium that is favorable for implantation can result from the use of a simple fixed dose of E2, with higher doses achieving favorable endometrial development in shorter time. Vaginal sonography of endometrial development before P administration is more accurate than endometrial biopsy in predicting a successful donor egg cycle. Endometrial preparation in donor oocyte programs can be simplified by the use of vaginal US monitoring.

Endometrium↗
PubMed1993

The effect of nalmefene on pulsatile secretion of luteinizing hormone and prolactin in men.

Luteinizing hormone (LH) and prolactin are released in pulses which are relatively synchronous in the luteal phase of the menstrual cycle in women. The concordance of LH and prolactin pulses in normal men has not been reported. The objectives of this study were firstly to determine whether LH and prolactin pulses are synchronous in men, and secondly to examine the effects of naloxone and a new orally active opiate antagonist, nalmefene, on LH and prolactin release in men. Three groups of normal male subjects received saline infusion (control n = 5), naloxone infusion (2 mg/h; n = 5) or nalmefene (10 mg p.o.; n = 6). Blood samples were collected every 15 min for 2 h before and 6 h after study medication for determination of LH, prolactin and testosterone by radioimmunoassay. Both naloxone and nalmefene resulted in a significant increase in LH pulse frequency and in mean serum LH and testosterone concentrations with no change in LH pulse amplitude, prolactin pulse frequency or amplitude. In controls, 61% of LH pulses were synchronous with prolactin pulses. There was a decrease in concomitance of LH and prolactin pulses with naloxone (48%) and nalmefene (24%; P < 0.025) administration. In contrast, 52% of prolactin pulses were concomitant with LH pulses in controls, while naloxone (100%) but not nalmefene (67%) resulted in a significant (P < 0.01) increase in pulse synchrony. The difference observed between naloxone and nalmefene on prolactin--LH pulse synchrony is probably due to differential opioid receptor activity at the pituitary and hypothalamic level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Characterization of abnormal one pronuclear human oocytes by morphology, cytogenetics and in-situ hybridization.

The morphology, chromosomal constitution and developmental capability of abnormal human oocytes (94/3500 oocytes; 2.7%) which after insemination exhibited only one pronucleus were examined. The majority of one pronuclear oocytes exhibited two or more distinct polar bodies. Dividing oocytes showed irregular chromosome distribution from haploid to diploid. Embryos resulting from abnormal oocytes displayed limited developmental potential. Many of them underwent fragmentation or were arrested at the 2- or 8-cell stage of development, and only some reached the morula or blastocyst state (11/35 oocytes). In approximately 45% (15/33) of examined oocytes, decondensed sperm heads or tiny nucleus-like structures were found in addition to a single nucleus. Chromosome Y was also detected in chromosomal preparations in approximately 10% of the oocytes by in-situ hybridization utilizing the human Y chromosome-specific DNA probe (DYZ3). These observations provided strong evidence that many of these oocytes originated from fertilized oocytes. The origin of the other one pronuclear oocytes could not be determined. Parthenogenetic activation of some oocytes cannot be excluded and other explanations concerning the origin of abnormal oocytes are discussed.

Adult↗
PubMed1993

Experimentally induced parthenogenetic activation of human oocytes.

A total of 486 unfertilized, aged human oocytes were exposed to ethanol, calcium ionophore A23187, phorbol ester or puromycin and examined for evidence of activation. Five per cent of control oocytes (3/58) were spontaneously activated. Of the two agents which cause the release of intracellular Ca2+ ions, Ca2+ ionophore induced activation of only 16% of unfertilized oocytes, while ethanol did not have any effect. Phorbol ester, a stimulator of protein kinase C, also resulted in limited activation (14% of oocytes). In contrast, puromycin, an inhibitor of protein synthesis, resulted in activation of 91% of the exposed oocytes. It is speculated that puromycin probably inhibits a specific cytostatic factor or factors which are responsible for maintenance of the metaphase II block. Morphologically activated oocytes usually retained the second polar body and formed subnuclei. The developmental potential of activated oocytes appeared to be reduced, with only some oocytes capable of a single division.

Calcimycin↗
PubMed1993

Adhesion formation after laparoscopic ovarian cautery for polycystic ovarian syndrome: lack of correlation with pregnancy rate.

OBJECTIVE: To assess adhesion formation after laparoscopic ovarian cautery in women with polycystic ovarian syndrome (PCOS) and the efficacy of Interceed Adhesion Barrier (Ethicon, Summerville, NJ) in their prevention. DESIGN: Prospective, randomized, blinded, clinical study of laparoscopic ovarian cautery with application of Interceed to one ovary, followed by short interval second-look laparoscopy, scoring of adhesions, and clinical follow-up. SETTING: Tertiary care clinic at a University teaching hospital. PATIENTS: Eight infertile women with PCOS who failed to conceive with previous clomiphene citrate (CC) therapy. RESULTS: Periovarian adhesions of varying severity developed in all women after laparoscopic ovarian cautery. Interceed showed no protective effect. Despite this finding, all women initiated regular menses after laparoscopic ovarian cautery and seven of eight women spontaneously conceived eight singleton pregnancies without any further therapy. CONCLUSION: Laparoscopic ovarian cautery should be considered in infertile women with PCOS who fail to respond to CC therapy. These women must be counseled with respect to the possible complication of postoperative adhesion formation.

Adult↗