Comparison of buserelin and nafarelin in IVF cycles and in subsequent frozen-thawed embryo transfer cycles.

OBJECTIVE: To compare two gonadotropin-releasing hormone agonists for down-regulation prior to superovulation in in vitro fertilization/embryo transfer treatment. METHODS: Infertility patients (n=181) were randomized to receive buserelin (1200 microg/day, n=90) or nafarelin (800 microg/day, n=91) intranasally starting in the luteal phase. Serum levels of LH, estradiol and progesterone were measured during the treatment. The cycles were compared with regard to number of oocytes, fertilization and implantation rates and achieved pregnancies. RESULTS: Serum LH was lower after two weeks on buserelin: 1.8 (1.3-2.4) IU/L (median, with lower and upper quartile in parenthesis), than after nafarelin: 2.6 (1.8-4.0) IU/L, (p=0.0001). No other differences in serum hormone levels could be detected. More oocytes were recovered in the buserelin group: 13.0 (8.0-19.0) vs 11.0 (6.8-15.0), (p=0.046), but the fertilization rate was higher in the nafarelin group (49.9%, vs 45.1%, p=0.023). Implantation rate was higher in the nafarelin group (26.28% vs 15.5%, p=0.030), but there were an equal number of deliveries in both groups (20.9% vs 15.6% per started stimulation, p=0.420). In the subsequent frozen-thawed embryo transfer cycles the implantation rate was 21.1% (nafarelin group) and 10.6% (buserelin group, p=0.067), the pregnancy rate/ET was 31.7% and 17.0% (p=0.107) and the delivery rate was 22.0% and 10.6% (p=0.148), respectively. CONCLUSIONS: Differences exist in IVF-cycles down-regulated with buserelin or nafarelin which might affect embryo quality and treatment outcome.

Nephrocalcinosis in rabbits--correlation of ultrasound, computed tomography, pathology and renal function.

Objective. The purpose of this study was to induce nephrocalcinosis (NC) in rabbits with phosphate, vitamin D, oxalate and furosemide, to determine the effect on renal function and to correlate detection on ultrasound (US) and computed tomography (CT) with pathology. Materials and methods. Seventy-five immature New Zealand white rabbits were divided into five groups of 15. In each group, 5 animals were controls and 10 were given oral phosphate, furosemide, vitamin D or oxalate. Unilateral nephrectomy was performed at 3-6 weeks, and 5 rabbits of each test group were withdrawn from the substance. Weekly US was performed as well as US, CT and measurement of serum creatinine at the time of nephrectomy and prior to planned demise. Results. A total of 140 kidneys in 75 rabbits had both pathological and US correlation, with CT correlation in 126. Forty rabbits developed nephrocalcinosis with early (post nephrectomy at 3-6 weeks) or late (post demise at 12-20 weeks) pathological correlation obtained in 53 kidneys. Forty-one of these kidneys were from test animals: 23 developed NC early, 18 late. Twelve controls developed NC: 4 early, 8 late. Comparing US and CT to pathology, the sensitivity was 96% for US, 64% for CT. Specificity was 85% for US and 96% for CT. In 109 kidneys, information on serum creatinine level was available to correlate with pathology. The mean creatinine level was 138 mmol/l for those with NC and 118 mmol/l for those without NC (P<0.001). Conclusion. In this study, the presence of NC was significantly associated with increasing serum creatinine. Overall, US was more sensitive and CT was more specific in the detection of NC.

Pattern and permanence of phosphate-induced nephrocalcinosis in rabbits.

Objective. The purpose of this study was to observe the pattern and permanence of phosphate-induced nephrocalcinosis (NC) in rabbits. Materials and methods. Thirty immature New Zealand white rabbits were divided into 10 controls and 20 test subjects who were given oral phosphate. Unilateral nephrectomy was performed at 3-6 weeks, and 10 of the test group were withdrawn from the substance. All surviving rabbits were terminated at 6-14 weeks post nephrectomy. Weekly US was performed, as well as US, CT and serum creatinine evaluation at the time of nephrectomy and prior to planned demise. Results. Of the 20 rabbits that received oral phosphate, 16 had NC by 3 weeks and the remainder by 6 weeks. The severity was proportional to intake. NC occurred in the cortex in 69%, the corticomedullary junction (CMJ) in 81% and the medulla in 27% of cases. Only 5 of 10 rabbits that returned to oral water post nephrectomy were suitable for follow-up on pathology. NC improved in 3 of these animals. Conclusion. NC in rabbits occurs maximally at the CMJ but also frequently in the cortex. NC was not permanent or static but improved in 3 of 5 rabbits when phosphate was withdrawn.

The effect of cryopreservation in prevention of ovarian hyperstimulation syndrome.

OBJECTIVE: To evaluate the effect of elective cryopreservation of all embryos in the prevention of severe ovarian hyperstimulation syndrome in women at increased risk, following superovulation for in vitro fertilisation. DESIGN: Three hundred and ninety women undergoing superovulation for in vitro fertilisation between September 1991 and December 1992. SETTING: University Infertility Clinic, Helsinki, Finland. INTERVENTIONS: Twenty-three women were considered to have an increased risk of developing ovarian hyperstimulation syndrome. They were characterised by more than 20 retrieved oocytes and/or by serum oestradiol levels exceeding 10,000 pmol/l on the day of administration of human chorionic gonadotrophin. Instead of cancelling the cycle the oocytes were harvested and fertilised, and all good quality embryos were cryopreserved. The embryos were thawed and replaced during subsequent natural cycles. MAIN OUTCOME MEASURES: Occurrence of ovarian hyperstimulation syndrome and pregnancy rate. RESULTS: One out of the 23 patients at increased risk developed a moderate degree ovarian hyperstimulation syndrome, while the others had only mild symptoms. Two of the remaining 367 women with no risk developed ovarian hyperstimulation syndrome, both during early pregnancy. Among the 23 patients at increased risk there have been 15 clinical pregnancies after transfer of two to three frozen-thawed embryos in natural cycles, with a 32.6% pregnancy rate. CONCLUSIONS: Withholding embryo replacement and elective cryopreservation of the embryos is effective in preventing severe ovarian hyperstimulation syndrome. After subsequent replacement in natural cycles the implantation rate per embryo is good (22.7%).

Fluoroscopic study of the birth posture of the sheep fetus.

Video-taped fluoroscopy was used in a research programme to review the characteristic attitudes of fetal limbs, head, neck and trunk, throughout the course of physiologically normal parturition in sheep. Nine fetuses from eight ewes were monitored during the whole process of natural birth by means of image-intensified X-ray fluoroscopy. All nine births were spontaneous and full term; with one exception they were unassisted. In all examinations the ewes were placed on their left sides on the X-ray table and lightly restrained with loose rope shackles. At parturition the ewes were fully conditioned to the examination procedure and had considerable limb mobility which allowed them to strain naturally during labour. No treatment was given to induce parturition or sedation. The consistency of observations was notable. A major finding was in the postural adaption of the forelimbs, taking the form of carpal extension with extreme flexion of the elbow and shoulder joints. This prepartum posture persisted throughout parturition in all monitored cases and is suggested as normal. The moulding effect of uterine contractions evidently acted on the hindquarters, contributing to their bunched (flexed) posture until mid-expulsion of the fetus. Full extension of all the hind limb joints occurred promptly when the fetal stifle region contacted the maternal pubis at terminal expulsion.