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The size distribution of marmoset luteal cells was determined on Days 6, 14 and 20 after ovulation in non-pregnant cycles and in early pregnancy. Image analysis was used to estimate the cell diameter of dispersed cells prepared from the marmoset corpus luteum (CL). Steroidogenic cells showed a size distribution consistent with one population of cells. There was a significant increase in mean cell diameter (P less than 0.05) from Day 6 to Day 14 in pregnant and non-pregnant animals with no further increase on Day 20. Micrographs of marmoset luteal tissue showed cells of greater than 10 micron containing the organelles typical of steroid-producing cells, and smaller non-steroidogenic cells surrounding the steroid-producing cells. On the basis of microscopy, there were no areas within the CL where cell composition was noticeably different. In contrast, micrographs of human luteal tissue showed two types of steroidogenic cell; most cells were similar to those in the marmoset CL but a smaller population of smaller cells could be distinguished around the periphery and along vascular septa. It is likely that these smaller and larger types of steroidogenic cells are of theca and granulosa cell origin respectively, the two cell populations differing in the degree of electron density and amount of rough endoplasmic reticulum. A distinguishing feature between marmoset and human luteal cells was the shape of the mitochondrian which were considerably rounder in marmoset luteal cells. The origin of steroidogenic cells in the marmoset CL is unclear, although in marmosets and man the luteal cell types display morphological characteristics distinct from the large and small luteal cells described for CL of the domestic ungulates.

The modeling and analysis of transient faults in microprocessor based controllers are discussed. Such controllers typically consist of a microprocessor, read only memory storing and application program, random access memory for data storage, and input/output devices for external communications. The effects of transient faults on the performance of the controller are reviewed. An instruction level perspective of performance is taken which is the basis of a useful high level program state description of the microprocessor controller. A transition matrix is defined which determines the controller's response to transient fault arrivals.

Objective: To determine whether a relation exists between previous exposure to Chlamydia trachomatis and impaired ovarian response to gonadotropin stimulation. Design: Controlled clinical study. Setting: Two university IVF centers. Patient(s): Two hundred forty-two patients receiving IVF treatment and 81 control patients. Ninety-four patients with a poor response to IVF, defined by cycle cancellation in response to a daily stimulation dose of 300 IU of FSH, and 148 patients with a good response were matched for age. Twenty-eight pregnant controls and 53 controls of proven fertility also were included. Intervention(s): Serum samples were obtained from patients and controls. Serum levels of immunoglobulin (Ig) G antibodies to C. trachomatis were determined by ELISA. Main Outcome Measure(s): The prevalence of serum IgG antibodies to C. trachomatis in critically defined poor responders was compared with that of age-matched good responders. Result(s): A significantly higher proportion of poor responders had serum IgG antibodies to C. trachomatis compared with good responders (44.7% and 30.4%, respectively). Patients undergoing IVF had a significantly higher prevalence of IgG antibodies to C. trachomatis (36%) than did either pregnant or nonpregnant controls (12%). Conclusion(s): A significantly higher prevalence of serum IgG antibodies to C. trachomatis was observed in critically defined poor responders, suggesting a possible detrimental effect of C. trachomatis on subsequent ovarian function.

Objective To investigate levels of placental protein 14 (PP14) in in vitro fertilization (IVF) patients with and without exogenous human chorionic gonadotropin (hCG) for luteal support. Design, Patients Thirty-one women undergoing IVF were studied. For 18 women, hCG was administered in the luteal phase, and 12 became pregnant. Five pregnancies occurred in 13 women not receiving exogenous hCG. Setting All the patients attended the University of Southampton/Chalybeate Hospital IVF program. Results There was no change in PP14 levels 2 days after embryo transfer (ET), but small significant rises were noted by day 8 in all patients. Thereafter, levels rose further in pregnant subjects but showed no change in nonpregnant patients. The highest level of PP14 was seen in the group of women on hCG support, but there was no overall statistical difference between those on support and those not. In the nonpregnant group, there was no significant correlation between progesterone (P) and PP14 8 days from ET, whereas a highly significant correlation was noted in the pregnant group. Conclusions Neither hCG nor P are primary factors in the control of endometrial PP14 secretion, but PP14 and P may have common underlying control mechanisms.

OBJECTIVE--To evaluate the effect of support with human chorionic gonadotrophin in the luteal phase in women taking part in an in vitro fertilisation programme after buserelin and human menopausal gonadotrophin were used to hyperstimulate their ovaries. DESIGN--Controlled group comparison. SETTING--Outpatient department of a private hospital. PATIENTS--115 Women with indications for in vitro fertilisation, all of whom had at least one embryo transferred. INTERVENTIONS--After suppression of the pituitary with buserelin the ovaries of all the women were stimulated with human menopausal gonadotrophin on day 4 of the luteal phase. Human chorionic gonadotrophin (10,000 IU) was given to induce ovulation, and oocytes were recovered 34 hours later. Embryos were transferred 46 to 48 hours after insemination. Women who had received the 10,000 IU of human chorionic gonadotrophin on a date that was an uneven number (n = 61) were allocated to receive support doses of 2500 IU human chorionic gonadotrophin three and six days after that date. The remaining 54 women did not receive hormonal support. END POINT--Determination of the rates of pregnancy. MEASUREMENTS and main results--Support with human chorionic gonadotrophin did not significantly alter the progesterone or oestradiol concentrations in the early or mid-luteal phase. The mean (range) progesterone concentrations in the late luteal phase in women who did not become pregnant were, however, significantly higher in those who received support (16(9-110) nmol/l nu 8(4-46) nmol/l), and the luteal phase was significantly longer in this group (14 days nu 12 days). The rate of pregnancy was significantly higher in the women who received support than in those who did not (25/61 nu 8/54). CONCLUSIONS--When buserelin and human menopausal gonadotrophin are used to hyperstimulate ovaries support with human chorionic gonadotrophin in the luteal phase has a beneficial effect on in vitro fertilisation.

A method is described for the separation of motile sperm from semen by "migration' into a diluent, providing a large area of interface between the semen and the diluent and resulting in a good yield of motile sperm (58%), with a mean percentage of motility of 95%. The method provides a specimen free of seminal plasma and debris and suitable for intrauterine insemination in less than two hours. The motile fraction was used for AIH treatment of 20 couples with a mean of 4 years' infertility, where the female factor had been excluded and the male was asthenospermic. After a mean of six cycles, three pregnancies were achieved. Improvement of the percentage of motility alone did not, in this study, give a significant improvement in conception rates when compared with accepted cycles with the placebo.