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Biomedical subjects

A C Wentz

Publications and source records attributed to A C Wentz.

At least 19 recordsLinked to original sources
PubMed1997

Strategies for ovulation induction and oocyte retrieval in the lowland gorilla.

PURPOSE: Ovulation induction and oocyte retrieval were performed in a lowland gorilla in an attempt to propagate and potentially cryopreserve embryos from an infertile animal and to advance techniques to help preserve this endangered species. RESULTS: Following 34 days of leuprolide acetate suppression, human menopausal gonadotropins were administered for 14-days in a 32-year-old wild-born lowland gorilla. Ten oocytes were retrieved by transrectal ultrasound-guided aspiration. Other approaches to oocyte recovery were not feasible in this case. A serum estradiol concentration of 4700 pg/ml at the time of human chorionic gonadotropin administration did not induce ovarian hyperstimulation. Mature oocytes were recovered from follicles measuring 14 to 24 mm in diameter, with a corresponding average serum estradiol concentration of approximately 300 pg/ml for each mature follicle. Cryopreservation of a gorilla embryo was effected from cryopreserved gorilla spermatozoa. CONCLUSIONS: Parameters for monitoring ovulation induction in the gorilla appear to be similar to those for humans. The results indicate that the use of a gonadotropin releasing hormone agonist and higher doses of gonadotropins than previously used in gorillas appear to improve oocyte recovery.

Animals↗
PubMed1997

Follicle stimulating hormone effects on immature human oocytes: in vitro maturation and hormone production.

PURPOSE: Our purpose was (1) to determine if in vitro maturation of unstimulated oocytes could be improved with the addition of urofollitropin; (2) to evaluate the output of estradiol, testosterone, progesterone, and androstenedione by the cultured oocyte-cumulus complex; and (3) to ascertain if steroid hormone production of the oocyte-cumulus complex correlates with final oocyte maturation stage. METHODS: Fifty-eight immature oocytes were obtained from 11 regularly cycling women undergoing oophorectomy. The oocyte-cumulus complexes were randomly assigned to control medium (Ham's F-10 supplemented with 7.5% fetal bovine serum) or test medium (control medium supplemented with 75 mIU/ml of urofollitropin). RESULTS: (1) The addition of urofollitropin to oocyte culture medium does not significantly increase the ability of the oocyte to achieve the metaphase II stage; (2) the addition of urofollitropin significantly increases the production of progesterone, testosterone, and androstenedione by the oocyte-cumulus complex; and (3) there is no difference in the production of estradiol, progesterone, testosterone, and androstenedione by the oocyte-cumulus complex at the germinal vesicle, metaphase I or metaphase II stage of oocyte maturation. CONCLUSIONS: This information is of importance in the use of oophorectomy specimens for patients who must undergo an oophorectomy but desire to attempt pregnancy using their oocytes, in the use of oophorectomy specimens for donor oocytes, or for patients undergoing in vitro fertilization using immature oocyte collection.

Androstenedione↗
PubMed1995

Estrogenic and antiestrogenic activities of anordiol: a comparison of uterine and vaginal responses with those of clomiphene citrate.

Anordiol (2 alpha,17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta,17 beta-diol) has been variously characterized as an estrogen and as an antiestrogen. To more completely understand the pharmacological properties of this contraceptive steroid, simultaneous responses were studied in uterine, vaginal, and hepatic tissues. Rats received 4 daily sc injections with either anordiol, clomiphene citrate (CC), or the vehicle alone (C+) starting on the first day of pseudopregnancy. Uteri were traumatized on day 4 of pseudopregnancy, and rats were sacrificed 5 days later. A pseudopregnant group without uterine trauma served as a negative control (C-). Mean uterine weights per animal and cytosolic estrogen (EcR) and progesterone (PcR) receptor activities per g of DNA were all 5- to 7-fold greater in the C+ group than in the other groups (all p < 0.05). However, anordiol and CC suppressed uterine weight without suppressing the stromal proliferative response; the DNA content of the uteri of anordiol- and CC-treated rats was similar to that of C+ rats. Vaginal tissue exhibited estrogenic responses to anordiol and CC with an increase in epithelial stratification compared to the C+ and C- groups even though no difference in levels of EcR/g of DNA were expressed 5 days after the last antiestrogen dose. Binding affinities and serum E2 and progesterone (P) concentrations were not statistically different among the groups. In conclusion, anordiol produced responses in the uterus and vagina of the pseudopregnant rat which were indistinguishable from those of CC, and, therefore, we conclude that anordiol acts on these tissues as an antiestrogen.

Animals↗
PubMed1995

TEST-yolk media and sperm quality.

Media prepared with egg yolk and two buffers, TES and Tris, called TEST-yolk have been shown to have beneficial effects on the survivability, fertilizing capacity and storage potential of human spermatozoa. Egg yolk lipoproteins are the critical compounds for the beneficial effects, with a synergistic effect due to the TES-Tris buffer component. TEST-yolk media have been used in the sperm penetration assay, the hemizona assay, sperm preparation for clinical in-vitro fertilization, artificial insemination with homologous spermatozoa, cryopreservation, sperm samples with a positive antisperm antibody test, and preparation for techniques requiring capacitated spermatozoa. Few harmful consequences of TEST-yolk have been reported, although controlled trials are required to evaluate therapeutic effects in the treatment of male infertility.

Cryopreservation↗
PubMed1994

Obstetrics and gynecology.

Emergency contraception could reduce the number of unintended pregnancies by 1.7 million. The best approach to oral contraception is education and not limitation, but it is unlikely that there will be any increase in contraceptive availability in the near future. Routine ultrasonography in low-risk pregnancies does not appear to be cost-effective.

Gynecology↗
PubMed1993

Comparison of the methods of artificial insemination on the incidence of conception in single unmarried women.

OBJECTIVE: To compare pregnancy rates after intrauterine insemination (IUI) versus pericervical insemination in absolute male factor infertility using each patient as her own control. DESIGN: Ovulatory women with patent fallopian tubes without male partners were alternately inseminated with cryopreserved donor semen using either IUI or pericervical insemination techniques. A total of 81 cycles, which included up to 4 cycles per patient were performed. In this manner a comparison between the efficacy of each method could be evaluated. SETTING: The donor insemination program at the Center For Assisted Reproduction at Northwestern University Medical School. PATIENTS: Twenty-six single, healthy, unmarried women with patent fallopian tubes and < 40 years of age without male partners (absolute male factor infertility). MAIN OUTCOME MEASURES: Positive quantitative serum subunit of human chorionic gonadotropin followed by the presence of an intrauterine gestational sac seen by transvaginal ultrasonography. RESULTS: Fourteen (54%) of 26 patients conceived including two (14%) miscarriages within four insemination cycles. Seven (17.5%) patients after IUI, and 7 (17.1%) patients after pericervical insemination conceived. The pregnancy rates were similar regardless of the order of insemination method. CONCLUSION: These findings reveal that there is no statistical difference in the pregnancy outcome between these two methods of insemination in absolute male factor infertility.

Adult↗
PubMed1993

Antiestrogenic potency of toremifene and tamoxifen in postmenopausal women.

In this nonblinded, controlled multicenter trial, postmenopausal women were randomly assigned to receive graded doses of toremifene and tamoxifen or no antiestrogen to assess dose-response levels and evaluation methodology. For standardization, transdermal estradiol (Estraderm-Ciba Geigy) was applied to all women for 38 days. The antiestrogens were added on days 29-38. For control and all treatment groups, there were no significant changes in serum chemistries or serum hormone levels, nor were there differences in adverse effects. The use of continuous estradiol precluded any meaningful assessment of the estrogenicity of tamoxifen or toremifene. As measured by vaginal superficial cytologic cell count changes, the antiestrogenic activity of toremifene doses ranging from 20 to 200 mg/day could not be distinguished from that of 20 mg/day of tamoxifen, the clinically recommended dose in North America.

Adult↗
PubMed1993

The impact of subchronic hypercortisolemia on progesterone metabolism and the luteinizing hormone-progesterone axis in the cynomolgus monkey.

The purpose of the study was to assess the impact of subchronic hypercortisolemia on progesterone (P) metabolism and production and on peripheral LH levels in a nonhuman primate using a repeated measures experimental design. Osmotic pumps that released hydrocortisone phosphate (HP) at a dose of 15 mg/day were implanted sc in seven cynomolgus monkeys for two menstrual cycles. The pumps were filled with saline for the two control cycles, which either preceded (three animals) or followed (four animals) HP infusion. P metabolism, P production, and episodic secretion of LH were determined 8 +/- 1 days after the serum estradiol peak in the second control cycle and in the second cycle of HP infusion in each monkey, after iv bolus administration of 50 microCi [3H]P, followed by a 6-h blood sampling period. HP infusion elevated serum cortisol levels 1.6-fold. Serum P levels were decreased throughout the luteal phase by 58% (P < 0.01). The MCR of P and the volume of distribution at steady state of P were increased by 200% during HP infusion (both P < 0.005). The production rate of P was increased by HP treatment in five of seven monkeys. HP infusion increased the ratio of 20 alpha-[3H]dihydroprogesterone to [3H]P in serum from 0.5 to 1.0 (P < 0.05) while decreasing the fraction of [3H]P and its metabolites excreted in urine from 20% to 11% (P < 0.05). Serum LH levels, determined over a 5.25-h period in the luteal phase, were elevated by 200% during HP treatment (P < 0.05). Episodic secretion of LH during treatment was characterized by a 660% increase in the pulse amplitude (P < 0.05) and an apparent decrease in the pulse frequency. The results of this study provide evidence that moderate elevation of serum cortisol levels for two menstrual cycles in primates 1) increases the MCR of P, which may be the cause of the observed decrease in serum P levels; and 2) elevates serum LH levels by amplifying its pulse amplitude, which may result in a compensatory rise in the production rate of P.

Animals↗
PubMed1993

Salpingitis or oophoritis: what causes fever following oocyte aspiration and embryo transfer?

BACKGROUND: Febrile morbidity following in vitro fertilization and embryo transfer (IVF-ET) is a rare but possibly serious complication. This report describes a case of salpingitis after IVF-ET and discusses the possible reasons for febrile morbidity following this common procedure. CASE: A 37-year-old woman undergoing IVF-ET for tubal factor infertility developed sudden, severe pelvic pain, fever, and leukocytosis 24 hours after ET. Laparoscopy revealed bilateral suppurative pyosalpinges with cystic, hemorrhagic ovaries. Pain, fever, and leukocytosis resolved with conservative surgery and intravenous antibiotic therapy. CONCLUSIONS: This case presents laparoscopic documentation of a rare complication of oocyte aspiration and/or ET, namely, salpingitis. Possibilities for the development of salpingitis following IVF-ET include activation of quiescent bacteria within the fallopian tubes from a previous pelvic infection, puncture of the bowel during oocyte aspiration, inoculation of the pelvis with cervicovaginal flora during oocyte aspiration, and introduction of bacteria-laden secretions or air into the fallopian tubes during ET. Although rare, the possibility of severe pelvic infection following IVF-ET warrants consideration of prophylactic antibiotic coverage.

Adult↗
PubMed1992

In vitro fertilization and gamete micromanipulation in the lowland gorilla.

PURPOSE: Our purpose was to utilize current reproductive technologies to treat an infertile female lowland gorilla. RESULTS: Following pituitary down-regulation with a gonadotropin releasing hormone agonist and follicular stimulation with human menopausal gonadotropins, transrectal ultrasound-guided aspiration of ovarian follicles yielded nine oocytes. Following failed fertilization with both epididymal and electroejaculated sperm, zona dissection and sperm injection were performed and produced one embryo, which was cryopreserved. Immature oocytes were obtained from ovarian sections and were either cultured in vitro or cryopreserved. CONCLUSIONS: This report demonstrates that in vitro fertilization techniques, including pituitary suppression, ultrasound-guided aspiration, micromanipulation, and cryopreservation, can be used to assist reproduction in the lowland gorilla.

Animals↗
PubMed1992

Fertilizing capacity of various populations of spermatozoa within an ejaculate.

To determine whether ejaculates consist of various populations of sperm with varying degrees of fertilizing capacity, semen was filtered through a glass-wool column and the filtrate aliquoted sequentially into three portions. The ejaculate and its respective filtrates were evaluated for progressive motility, ability to respond to hypoosmotic swelling (HOS) test, acrosin content, ability to capacitate and acrosome react (AR), and ability to penetrate into denuded hamster oocytes (SPA). Filtrate 1 contained significantly more sperm with progressive motility, increased acrosin content, and positive HOS and SPA results than did the ejaculate. AR did not differ between the ejaculates and the respective filtrates. The data suggest that the ejaculate consists of various populations of sperm with different properties and that these populations may be separated by glass-wool filtration.

Acrosin↗
PubMed1992

Endometrial receptivity and the luteal phase.

Endometrial receptivity to the implanting blastocyst determines whether pregnancy occurs. Whether fertilization is initiated in vivo or in vitro, the receptivity of the luteal-phase endometrium results from the input of interacting hormonal, growth, and immunologic factors. Endometrial adequacy for implantation has traditionally been assessed by the endometrial biopsy. Newer methods used to study the endometrium, such as ultrasound imaging and measurement of endometrial proteins, have increased our understanding yet have demonstrated the limits of our knowledge. This review is designed to analyze the available literature for concepts and scientific facts to aid in our understanding of the complex events required in preparation of a receptive endometrium. Special attention is focused on the effect of supraphysiologic levels of steroid hormones on the endometrium in ovulation induction. The effect of both embryo quality and luteal-phase support are also reviewed.

Embryo Implantation↗
PubMed1991

Inhibition of estrogen biosynthesis in the rat ovary by anordrin.

The delay in appearance of vaginal cornification associated with administration of anordiol (de-esterified anordrin) in the post-ovulatory period was confirmed. Ovarian tissue incubated in vitro for 2 h on the day which, in normal cycles, would be the day of proestrus produced negligible amounts of estradiol even in the presence of androstenedione and human menopausal gonadotropin, despite the appearance of apparently mature follicles in the ovaries. Ovaries of untreated rats produced significant amounts of estradiol when androstenedione was present. Continued incubation for 3 days resulted in significant estradiol production by ovaries of anordiol-pretreated rats in the presence of androstenedione, but less than that of ovaries of control rats. Granulosa cells of immature rats pretreated with diethylstilbestrol (DES) were unaffected by pretreatment with anordrin, whether anordrin was given before or after DES treatment. Taken together, the results indicate that anordiol inhibits development of the capacity for estrogen secretion in maturing follicles without affecting structural development, but that follicles that grow under the influence of high concentrations of estrogen (DES) are unaffected by the presence of anordrin (which is rapidly converted to anordiol in vivo). The latter result suggests that DES treatment bypasses the anordiol-sensitive step in follicular maturation.

Analysis of Variance↗