von Willebrand factor: an endothelial marker to monitor in-vitro fertilization patients with ovarian hyperstimulation syndrome.

A retrospective study was conducted to evaluate the possible role of endothelial and extracellular factors in the pathophysiology of ovarian hyperstimulation syndrome (OHSS). Plasma changes in von Willebrand-Jürgen factor were correlated with the clinical condition of hyperstimulated patients, since the rise of capillary permeability is the central event in all subsequent morbidity. The corresponding oestradiol levels and ultrasound parameters were assessed. In-vitro fertilization patients designated as 'high responders' and with oestradiol values > 2500 pg/ml and > 8 pre-ovulatory follicles at the time of human chorionic gonadotrophin (HCG) injection were assessed. Among 62 patients, 37 fulfilled these criteria and 18 developed OHSS, indicating the low predictive ability of ultrasound and oestradiol values alone. The remaining 19 patients served as control group. von Willebrand factor-associated antigen in plasma was measured using enzyme-linked immunosorbent assay and ristocetin co-factor activity by an aggregatometric test. Basal values of the two groups of patients did not differ but there were large inter-individual variations. A slight increase occurred in the control group until the day of HCG although individual cycles showed 'no change of pattern' or a 'decreasing tendency' from the start. Some patients allocated to the non-hyperstimulated type showed a steep increase of values followed by a decline. A consistent increase in the OHSS group lasted after embryo transfer even to the late corpus luteum phase. These subtle changes of capillary permeability or damage always preceded the clinical signs, such as ascites, haemoconcentration, hypoproteinaemia and pleural effusion. Mean values differed in the two groups from the day preceding ovum retrieval.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryopreservation of human and rabbit oocytes and one-cell embryos: a comparison of DMSO and propanediol.

The aim of this study was to improve the cryopreservation of human oocytes and pronuclear embryos. One-step and multiple-step addition of dimethyl sulphoxide (DMSO) and 1,2-propanediol (PROH) and three different freezing protocols with intermediate temperatures of -35, -70 and -110 degrees C were investigated. This work was performed using rabbit oocytes as well as human oocytes and one-cell embryos from the routine IVF programme. Also, human polyploid pronucleate oocytes were used in controlled prospective studies of morphological intactness and development in vitro. Rabbit oocytes survived best (113/126) when PROH was added in one step and controlled freezing stopped at -110 degrees C. But the development was better (141/187) if DMSO was added in multiple steps and the oocytes were cooled to -70 degrees C before being plunged into liquid nitrogen. The mode of addition of the cryoprotectant influenced development only if slow freezing was stopped at -35 degrees C (51 versus 34%). Using PROH, the development after thawing was also better if cooling was stopped at -35 degrees C (51 versus 37%) and DMSO was superior to PROH when the oocytes were cooled slowly to -110 degrees C (66 versus 37%). In the human, significantly more pronucleated than unfertilized oocytes developed after freezing (92 versus 50%). The best results were achieved with pronuclear embryos using 1.5 M PROH and cooling to -110 degrees C, when 91.7% of the surviving oocytes developed further. This is a marked improvement of the development rate and comparable to embryo freezing.