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Biomedical subjects

R A Loy

Publications and source records attributed to R A Loy.

6 recordsLinked to original sources

Selection bias in in vitro fertilization programs.

Pregnancy rates per cycle reported from different in vitro fertilization-embryo transfer programs vary widely. While several programs have reported constant pregnancy rates per cycle, others report declining pregnancy rates. Selection biases at the point of entry and between cycles are discussed as possible explanations of these discrepancies.

Bias

Ovarian steroids modulate human monocyte tumor necrosis factor alpha messenger ribonucleic acid levels in cultured human peripheral monocytes.

OBJECTIVE: To determine whether tumor necrosis factor alpha (TNF-alpha) messenger ribonucleic acid (mRNA) levels in human peripheral monocytes are regulated by ovarian steroids. DESIGN: Human granulosa-luteal cells and cultured, activated human peripheral monocytes were subjected to Northern blot analysis for TNF-alpha mRNA. SETTING: Academic research laboratory. PATIENTS: Two human female volunteers of reproductive age and in the luteal phase of the menstrual cycle. RESULTS: Human granulosa-luteal cells produce TNF-alpha mRNA. Physiological levels of progesterone (P) and estradiol (E2) modulate TNF-alpha mRNA from peripheral blood monocytes with an apparent inverse relationship between steroid concentration and TNF-alpha message. CONCLUSIONS: Progesterone and E2 at physiological concentrations regulate TNF-alpha mRNA production. The P antagonist mifepristone (RU486) and the E2 agonist/antagonist tamoxifen modulate total TNF-alpha mRNA levels, suggesting involvement of specific receptors.

Cells, Cultured

Pulmonary function changes following exercise.

Many studies have documented differing changes in forced vital capacity (FVC) following various intensities and durations of exercise. This investigation used three different intensities and durations of treadmill running, with subjects who were active runners, with the intent of finding an intensity or duration that might elicit changes in FVC and if these changes are related to respiratory muscle fatigue. Intensities and durations included a graded maximal test to exhaustion (7-14 min); a 7-min test at 90% of maximal VO2, and a 30-min test at 60% of maximal VO2 (intensity). Maximal inspiratory pressures (MIP), maximal expiratory pressures (MEP), forced expiratory volume in 1 s (FEV1.0) and FVC were measured pretest, and 5, 10, and 30 min post-test (time). MIP was not different across time or intensities. The decrease in MEP approached significance at 10-min post-exercise compared to pretest values (P = 0.0569), with no differences found between intensities. FVC was different between times (P = 0.0117) but not between intensities. FVC was decreased at 5 and 10 min post-test compared with pre and 30 min. FEV1.0 was significantly reduced at 5 and 10 min post-test compared with pretest. These data suggest that a combination of duration and intensity may be necessary to elicit pulmonary function changes after exercise and that expiratory muscle fatigue may be a factor that results in a reduced FVC.

Adult

Heterogeneity in patient populations explains differences in in vitro fertilization programs.

OBJECTIVE: To evaluate the efficacy of in vitro fertilization and embryo transfer (IVF-ET). DESIGN: Two different models for pregnancy rates in IVF-ET have been developed: a beta-geometric model and a split population model. SETTINGS: All IVF cycles were performed at the Yale University School of Medicine in New Haven, Connecticut. PATIENTS, PARTICIPANTS: All patients undergoing 1,257 IVF-ET cycles performed between the years 1983 through 1987. INTERVENTIONS: None. MAIN OUTCOME MEASURE: The probability of achieving a viable pregnancy per cycle. RESULTS: Because both models provide excellent explanations for our data distribution, the decline in the conditional probability of achieving pregnancy after a given number of unsuccessful cycles may be inferred. CONCLUSIONS: These findings question the justification of continuing IVF-ET treatment beyond some threshold number of cycles.

Embryo Transfer

Human follicular fluids contain tissue macrophages.

Tissue cells obtained from the follicular fluids of women undergoing in vitro fertilization and embryo transfer were found to contain interleukin-1 beta mRNA by Northern analysis. Since macrophages are known to produce interleukin-1 beta, we examined the follicular fluids of 20 women undergoing in vitro fertilization as well as tissue sections of normal human ovary for the presence of macrophages and monocytes. Although granulosa-luteal cells predominate in follicular fluid, we found that resident macrophages and monocytes comprise 5-15% of human follicular tissue cells. In addition, we observed that macrophages are present in the human ovarian follicle as well as in the corpus luteum.

Blotting, Northern

Femoral neuropathy after laparoscopy. A case report.

Femoral neuropathy has been reported to occur after abdominal hysterectomies and has been related to nerve compression by abdominal wound retractors. We report a case of a 35-year-old woman with infertility who developed unilateral femoral nerve palsy after laparoscopy and hysteroscopy. This rare complication, secondary to extreme flexion, abduction and lateral rotation of the hip joint, can be prevented by careful preoperative patient positioning.

Adult