Assessment Of Embryo Viability Research Articles

Early pregnancy factor as a marker for assessing embryonic viability in threatened and missed abortions.

It is now well recognized that the presence of early pregnancy factor (EPF) can signify the occurrence of fertilization, continuation of pregnancy and the existence of a viable embryo. With this in view, a study was undertaken to observe the potential of EPF as a marker in assessing embryo viability in cases complicated with vaginal bleeding during early pregnancy. The results indicated that the sensitivity of EPF as a marker in predicting threatened or missed abortion was 78.9% and the specificity 95.6%. The positive predictive value was observed to be 93.8% and the negative predictive value 84.6%. Our studies have shown that since EPF is present in viable but absent in non-viable pregnancies, it could be a useful marker of prognostic value in threatened abortions.

Fluorescein diacetate assessment of embryo viability after ultrarapid freezing of human multipronucleate embryos

To assess embryo viability after ultrarapid freezing-thawing. We studied the fluorescence pattern of 35 ultrarapidly frozen-thawed multipronucleate human embryos exposed to fluorescein diacetate. All the embryos were obtained from the Medical Center for Fertility Diagnostics and In Vitro Fertilization and Embryo Transfer at Leuven (Belgium), a private care center. None. None. The fluorescence pattern was evaluated at room temperature after a 1-minute incubation in fluorescein diacetate solution, 4 hours and 24 hours after thawing. Healthy human multipronucleate embryos, when exposed to fluorescein diacetate, accumulated intracellular fluorescein and fluoresced brightly under ultraviolet light. On the other hand, embryos presenting submicroscopic cell membranes damage caused by different processes (e.g., high or low temperatures) lost the ability to accumulate intracellular fluorescein. All the ultrarapidly frozen embryos with normal looking blastomeres fluoresced brightly after a short exposure to fluorescein diacetate. Our experiments indicate an intact cell membrane permeability and an integrity of the intracytoplasmatic esterase enzyme activity of human embryos ultrarapidly frozen.

Effect of immunization on reproducvive performance, embryo quality and progesterone in Rasa Aragonesa ewes actively immunized against androstenedione or passively immunized against testosterone

A total of 217 Rasa Aragonesa ewes were used to test two immunization treatments: 1.Active immunization against androstenedione: ewes immunized in previous matings (androstenedione, reimmunized; AR groups, n=58) or not (first immunization; AF groups n=64) were boosted either 2 or 4 wk before mating. 2.Passive immunization against testosterone: antisera were injected either at sponge withdrawal (zero time; T0 group, n=21) or 1 wk previously (Tl group, n=22). We used 52 ewes as controls (C group). Half of each group was used either to record reproductive performance or to embryo viability assessment. Prolificacy was significantly increased in ewes which reached a moderate antibody level, independently of the treatment. Fertility was lower in AR ewes that attained a high antibody titre (P<0.01). The percentage of viable embryos recovered was lower in AF ewes (P<0.01), and in ewes whose testosterone antibody titre was high (P<0.05), compared to C group. It was proven that similar or lower antibody levels were more harmful for ewes from AF and Tl than for ewes from AR or T0 groups. The proportion of nonfertilized recovered ova was not significant. Progesterone levels were notably increased in AR ewes (P<0.001) independently of ovulation rate and were positively correlated to antibody titre at mating (P<0.01) but these events were not observed in T ewes. These findings indicate that after androgen immunoneutralization, only those ewes having antibody titres within a limited range at mating had improved reproductive performance. Further research is needed in order to understand the role that progesterone plays in immunized ewes.

Viability of inner cell mass versus trophectodermal cells of frozen‐thawed horse embryos

SummaryFluorescein diacetate (FDA), a fluorogenic vital stain, was used in conjunction with a silicon‐intensified target (SIT) camera and computer‐based image analysis to estimate the viability of cells of the inner cell mass (ICM) and trophectoderm (TE) of freshly collected and frozen‐thawed horse embryos. Fluorescence intensities were greater (p&lt;0.02) for fresh ICM (0.1500) and TE (0.1686) than for frozen‐thawed ICM (0.0323) and TE (0.0694). Fluorescence intensity ratios (ICM:TE) also differed (p&lt;0.004) between fresh (0.966) and frozen‐thawed (0.482) embryos. These results indicate that 1) the use of FDA coupled with SIT camera image analysis is a repeatable, objective method for assessing embryo viability and 2) the freeze‐thaw process is more detrimental to ICM cells than to TE cells of horse embryos.

Uptake of pyruvate by early human embryos determined by a non-invasive technique.

Normal levels of pyruvate in freshly collected follicular fluid were found to be 0.45 mM, a value approximately 4 X that of serum. The utilization of pyruvate by human oocytes and early embryos has been measured, non-invasively, using two similar but separate analytical methods. The mature oocyte has a high level of pyruvate uptake (36 pmol/embryo/h). After fertilization this value falls, and then slowly increases to reach a peak just prior to the morula stage of 27 pmol/embryo/h before decreasing. Degenerating oocytes and embryos demonstrated much lower pyruvate uptake rates. The possible usefulness of this method for assessing embryo viability is discussed.

Maternal blood platelet physiology and luteal-phase endocrinology as a means of monitoring pre- and postimplantation embryo viability following in vitro fertilization.

The discovery that the fertilized mouse ovum triggers an increased demand for platelets and results in thrombocytopenia during the preimplantation phase of pregnancy provides a monitor for embryo survival and viability. This paper reports a study in which the platelet count was significantly reduced throughout the human preimplantation phase of pregnancy and returned to normal following embryo implantation. The human embryo was shown to produce a platelet activating factor in vitro which caused the reduction in platelet count after embryo transfer. This factor in the embryo culture medium could be measured using a bioassay which provided a means of assessing embryo viability prior to transfer. Some women showed no reduction in platelets after transfer. These embryos failed to produce a platelet activating factor in vitro and pregnancy was not established. Other women displayed a reduction in platelets following transfer but failed to become pregnant. All of these women had elevated luteal-phase plasma E2 levels compared to pregnant patients, which may have interfered with the implantation process. Our observations provide a possible rapid and simple means for monitoring the viability of human embryos cultured in vitro and the survival of embryos in utero.

Development and viability of frozen-thawed cattle embryos

Embryos recovered 7 to 8 days after estrus were frozen from −7 to −30°C at 0.3°C/min, from −30 to −33°C at 0.1°C/min, and then plunged into liquid nitrogen. They were thawed in a 25°C waterbath. In a preliminary study, 15 of 18 embryos continued to develop during the 24-hour culture post-thaw in either Ham's F-10 or modified Dulbecco's phosphate buffered saline (PBS). In the main study, 5 of 20 embryos developed to 60-day pregnancies when embryos were transferred within 5 hours after thawing. The incidence of extended estrous cycles (pregnancy or presumed embryonic mortality) was 10 of 14, when the zona pellucida was intact after thawing, and 0 of 6, when it was ruptured or absent (P<.05). Embryos cultured in PBS tended to develop more readily than those in Ham's F-10 (15 of 20 vs 9 of 20, respectively, P⋍.1). Quality of the embryos, at recovery from the donor and after thawing, affected development in culture (19 of 27 embryos excellent at recovery developed vs 5 of 13 poor to very good, P⋍.1; 23 of 33 embryos good to excellent after thawing developed vs 1 of 7 poor, P<.05). The proportion of pyknotic nuclei in embryos which were cultured ranged from 18 to 100%. The pregnancy rate from embryos which were cultured was low (2 of 20). Thirty percent of frozen and thawed embryos had damaged zonae pellucidae. The study showed that: the pregnancy rate from frozen embryos was approximately half that achieved with unfrozen embryos; culturing embryos for 24 hours before transfer was not beneficial; the PBS culture system appears to be the system of choice for assessing embryo viability in vitro .