An analysis of human oocytes and follicles from stimulated cycles: oocyte morphology and associated follicular fluid characteristics.

The aim of this study was to determine whether certain characteristics of the follicular biochemistry, previously shown by us to be associated with oocyte developmental capacity, also reflected differences in oocyte appearance, and to determine the range of oocyte characteristics induced by ovarian stimulation. A representative sample of 33 human oocytes and associated follicular fluids was obtained after a follicular growth period considered suitable for IVF. Individual follicular fluid protein and proteoglycan levels, and follicular volume were compared with the morphological characteristics of each oocyte. Oocytes which retained the germinal vesicle nuclear status after exposure to human chorionic gonadotrophin tended to occur in small follicles (less than or equal to 2 ml) and to be highly vacuolated and with characteristic predicted a low potential for cleavage. Among those oocytes which had progressed to MII nuclear maturity [in the medium (2.5-6.5 ml) and large (greater than or equal to 7 ml) volume follicles] the degree of oocyte vacuolation was negatively correlated with alpha 1-antitrypsin level, while the degree of organelle clumping was correlated with proteoglycan and immunoglobulin levels. Only five of the oocytes (15%) in this sample had follicular characteristics consistent with a normal potential for pregnancy. These MII oocytes occurred within the medium volume range, had low vacuolation levels, and a low degree of organelle clumping. In contrast, those oocytes with a low potential for cleavage based on their follicular biochemistry, showed high cytoplasmic vacuolation levels.

Vasopressin release in sheep following various degrees of rehydration.

Restriction of the water intake of sheep to 0.5 1/day for 7-9 days increases plasma arginine vasopressin (pAVP), and voluntary rehydration causes a rapid fall in pAVP with no change in plasma osmolality. The extent of that inhibition of AVP release was assessed by comparing the decline of pAVP after drinking with pAVP disappearance curves obtained in the same sheep after stopping a constant infusion of AVP at 0.5 micrograms/h, which increased pAVP to the dehydration level. The fall in pAVP after drinking was almost identical with the disappearance curve showing that AVP release was almost completely inhibited during the 2-3 min taken for the sheep to drink 3-5 liters to satiate themselves. The response seemed, therefore, to be cued before the intake reached the satiating volume. When dehydrated sheep drank only 0.5 or 1.0 liter, in 30 s or less, pAVP again fell rapidly but only to a minimum approximately 15 min after drinking. The pAVP was unaltered in dehydrated sheep presented with water but denied access to it. Thus satiation was not necessary for rapid inhibition of AVP release after drinking, but satiation was necessary for this inhibition to be maintained. The initial inhibition was associated with falls in hematocrit and plasma total protein but not plasma osmolality. This isosmolar dilution occurred even in sheep that saw but were denied access to the water and suggests a shift of fluid from the extravascular space.

Follicular characteristics associated with viable pregnancy after in vitro fertilization in humans.

The aim of this study has been the development of a noninvasive method of predicting the pregnancy potential of human oocytes and embryos intended for in vitro fertilization and embryo replacement. A multifactorial system which distinguishes, with a high degree of accuracy, between normal pregnancy, abnormal pregnancy, and non-pregnancy-producing embryos is reported. The variables included are (1) follicular fluid proteins alpha 1-antitrypsin, complement C3, immunoglobulin IgG2, and total protein, and total proteoglycan level separated by isoelectric focusing; (2) follicular volume; and (3) an embryo appearance rating. The study group consisted of (1) follicles which produced embryos of known performance after transfer (a) when the number of embryos transferred = the number of implantations and, (b) where one embryo transferred = no pregnancy; (2) follicles which produced oocytes which did not cleave after insemination; and (3) follicles from which no oocyte was aspirated. Canonical discriminant analysis of follicular fluid variables and follicular volume has been used to characterize the oocyte performance groups. Correct classification was achieved in 69% of normal pregnancy, 70% of abnormal pregnancy, 33% of no pregnancy, and 47% of no cleavage oocytes. An embryo appearance rating was included with the above variables for a separate discriminant analysis of only those oocytes which had formed embryos after insemination. Correct classification was achieved in 81% of normal-pregnancy, 70% of abnormal-pregnancy, and 70% of no-pregnancy embryos.