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Biomedical subjects

M P Steinkampf

Publications and source records attributed to M P Steinkampf.

14 recordsLinked to original sources
PubMed1992

Inhibition of preimplantation mouse embryo development by isoflurane.

OBJECTIVE: Preimplantation mouse embryos were exposed to a commonly used inhalational anesthetic agent, isoflurane, to determine its effects on embryo development. STUDY DESIGN: Two-cell embryos were exposed at various intervals (5 to 6 hours, 3 to 4 hours, and 0 to 1 hour) before the onset of their first cleavage in vitro. In addition, the effects of 5% isoflurane on four-cell embryos exposed about 2 hours after the first cleavage and morula stage embryos also were examined. RESULTS: Development to the blastocyst stage was inhibited by 3% and 5% isoflurane (p less than 0.005) but not by 1.5% isoflurane when two-cell embryos were exposed 3 to 4 hours or 0 to 1 hour before the onset of cleavage. Most of the affected embryos completed cell division and came to a halt at the three- to four-cell stage. The development of embryos exposed to isoflurane at the four-cell or morula stage was unaffected. CONCLUSIONS: Isoflurane adversely affects subsequent preimplantation development when two-cell mouse embryos are exposed just before the onset of their first cleavage in vitro.

Animals↗
PubMed1992

A simplified approach to in vitro fertilization.

A simplified protocol for in vitro fertilization treatment was developed using low-dose clomiphene for ovarian stimulation, timing of human chorionic gonadotropin administration based solely on sonographic criteria, in-office egg retrieval and use of a simplified culture medium for embryo culture. Twenty-six infertile women underwent 39 treatment cycles, with 33 egg retrievals resulting in 29 embryo transfers. Clinical pregnancy was obtained in six patients (20.7% per embryo transfer), for a rate comparable to that achieved with conventional in vitro fertilization treatment in an age-matched control group. This simplification of in vitro fertilization treatment protocols can lead to decreased patient stress and costs without a substantially lower success rate.

Adult↗
PubMed1991

Visualization of free peritoneal fluid with transvaginal sonography. A preliminary study.

Visualization of free peritoneal fluid during sonographic examination is often of considerable clinical importance. To determine the sensitivity of transvaginal sonography in the detection of this finding, measured amounts of isotonic saline were instilled into the abdominal cavities of 15 women undergoing diagnostic laparoscopy while a 5-MHz transvaginal probe was employed to view the pelvic contents. Small amounts of free fluid could be visualized easily in all the patients (mean +/- SD, 25.8 +/- 6.4 mL). Fluid was first seen in the cul-de-sac in 10 patients and in the adnexal region in 5. When fluid instillation was continued to a total volume of 200 mL, the pelvic viscera were distinctly outlined in all the patients, markedly enhancing visualization of the uterus, tubes and ovaries. Transvaginal sonography seems to be a sensitive and reliable method of detecting free peritoneal fluid. Instillation of fluid into the peritoneal cavity may be a clinically useful technique for enhancing the sonographic visualization of pelvic structures.

Ascitic Fluid↗
PubMed1990

Performance anxiety during infertility treatment: effect on semen quality.

The requirement to obtain a semen sample at a specific time for an infertility treatment procedure has potential to produce considerable performance anxiety. This study was designed to evaluate the semen quality of men participating in infertility treatments associated with heightened performance anxiety. The most recent pretreatment semen analysis and the infertility treatment semen analysis, as well as the first and last procedure semen analyses, were compared using paired t-tests for 77 patients undergoing assisted reproductive technology procedures and 121 patients undergoing intrauterine insemination. No significant differences were noted in either of these groups of patients. However, in men with total motile sperm counts of less than 40 million, semen parameters improved significantly in the procedure semen analyses. Thus, participation in infertility treatments associated with performance anxiety does not appear to be detrimental to semen quality, and in certain groups of patients semen quality may improve.

Adult↗
PubMed1990

Use of molecular probes to study regulation of aromatase cytochrome P-450.

Aromatase, an enzyme complex localized in the endoplasmic reticulum of estrogen-producing cells, is composed of NADPH-cytochrome P-450 reductase, and aromatase cytochrome P-450 (cytochrome P-450AROM). To define the molecular mechanisms involved in the multifactorial regulation of cytochrome P-450AROM in estrogen-producing cells, we have isolated a cDNA specific for human cytochrome P-450AROM and have used this cDNA to isolate the human cytochrome P-450AROM gene. The cDNA sequence encodes a polypeptide of 503 amino acids and contains--near the carboxy-terminus, a region of high homology with the putative heme-binding regions of other P-450 cytochromes. COS1 cells transfected with an expression plasmid containing the cytochrome P-450AROM cDNA had the capacity to aromatize testosterone, androstenedione and 16 alpha-hydroxyandrostenedione, suggesting that a single polypeptide catalyzes all steps of the aromatization reaction using either of the three major C19-substrates. The human cytochrome P-450AROM gene is greater than 52 kb in size and consists of 10 exons and 9 introns. Hormonally induced changes in aromatase activity of human ovarian granulosa and adipose stromal cells are associated with comparable changes in cytochrome P-450AROM gene expression and synthesis, whereas the reductase component is only modestly affected. Studies are in progress to define the molecular mechanisms involved in the regulation of cytochrome P-450AROM gene expression in estrogen-producing cells.

Adipose Tissue↗
PubMed1990

Effects of nitrous oxide on preimplantation mouse embryo cleavage and development.

Preimplantation mouse embryos were exposed to nitrous oxide for 30 min to determine its effects on subsequent development after short durations of exposure. Two-cell mouse embryos were exposed to 60% nitrous oxide/40% oxygen at 6-7 h, 3-4 h, or 0-1 h prior to the expected onset of their first cleavage in vitro, or at the 4-cell or morula stages. Effects of nitrous oxide were not observed except in 2-cell embryos treated within 4 h of the expected in vitro cleavage. At 3-4 h and 0-1 h prior to the onset of cleavage, exposure to 60% nitrous oxide/40% oxygen resulted in blastocyst development rates of 27.7% and 4.7%, respectively, while control rates ranged from 75% to 77%. The majority of affected embryos were halted at the 2-cell stage before completing cell division. Similar effects were obtained with 80% nitrous oxide/20% oxygen. Thus, we conclude that brief exposure of mouse preimplantation embryos to nitrous oxide may be deleterious to subsequent embryo cleavage, but this effect is highly dependent on the developmental stage at which exposure occurs.

Animals↗
PubMed1990

Hormonal treatment of functional ovarian cysts: a randomized, prospective study.

Estrogen (E)/progestin therapy for functional ovarian cysts is widely used in clinical practice, but the efficacy of this treatment has not been determined in controlled trials. In this study, we examined the effect of E/progestin administration in a group of infertility patients enrolled in a program of ovulation induction who had cysts identified by transvaginal sonography. Patients were randomized to receive either norethindrone 1 mg/mestranol 0.05 mg/d (group A, n = 24) or no treatment (group B, n = 24) for up to 6 weeks. Patients were re-evaluated by sonography at 3, 6, and 9 weeks after entry into the protocol. The ages, mean cyst diameters, and proportions of patients having received gonadotropins in the previous menstrual cycle were not significantly different among the two groups. All patients who had a sonographic abnormality persisting for 9 weeks were surgically explored and found to have pathological cysts. The rate of disappearance of functional ovarian cysts was not affected by E/progestin treatment.

Adult↗
PubMed1990

Systemic illness and menstrual dysfunction.

Menstrual dysfunction can be associated with a number of systemic illnesses. Whereas the effects of some diseases on the reproductive system are simply a result of the pathophysiology of the disorders, in other cases, temporary cessation of reproductive function conserves energy for other tasks related to survival and well being.

Female↗
PubMed1989

Postoperative recuperation: relation to the extent of endoscopic surgery.

Ninety patients undergoing a total of 92 endoscopic procedures were assessed regarding their subjective recovery times, their delays in returning to their places of employment, the duration of analgesic use, and their inhospital stays. A significant association (P less than 0.05) between recuperation parameters and the extent of the intra-abdominal surgery at laparoscopy was observed. A weak association also was noted between the number of incisions performed, the duration of surgery, and postoperative recuperation. Nonetheless, even the most radical endoscopic procedures required considerably less recuperation time when compared with laparotomies. With the out-of-work period reduced 5- to 6-fold, obese individuals appeared to tolerate these procedures as well as their thin counterparts.

Abdomen↗
PubMed1988

Transvaginal sonography.

Transvaginal sonography can overcome some of the inherent limitations of the transabdominal technique. Scanning with a transvaginal probe often provides increased resolution and greater patient comfort. This technique is likely to be employed more frequently in the future for the evaluation of numerous gynecologic problems.

Female↗
PubMed1987

Regulation by follicle-stimulating hormone of the synthesis of aromatase cytochrome P-450 in human granulosa cells.

The effects of FSH to increase the activity of aromatase, as well as the synthesis of the components of the aromatase enzyme complex, have been studied in human ovarian granulosa cells obtained from women undergoing oocyte retrieval. FSH increased aromatase activity, as well as the synthesis of aromatase cytochrome P-450 (P-450AROM) in a time-dependent fashion, whereas in the absence of FSH, both activity and synthesis declined with duration of culture. The effect of FSH was mimicked by forskolin, an activator of adenylate cyclase. FSH also increased the synthesis of NADPH-cytochrome P-450 reductase, but to a relatively modest extent. The levels of hybridizable mRNA species encoding cytochrome P-450AROM of lengths 3.0, 2.4, and 1.6 kilobases were also increased with FSH treatment. It is concluded that the regulation of aromatase activity by FSH in human granulosa cells is mediated primarily by changes in the synthesis of cytochrome P-450AROM, that this action of FSH is mediated by cAMP, and that the changes in cytochrome P-450AROM synthesis are the consequences of changes in the levels of mRNA encoding this enzyme.

Aromatase↗