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PubMed2006

Ultrasonographic-guided embryo transfer does not enhance pregnancy rates compared with embryo transfer based on previous uterine length measurement.

OBJECTIVE: To compare pregnancy rates (PRs) after ultrasound-guided embryo transfer and embryo transfer based on ultrasonographic length measurement. DESIGN: Prospective intervention group combined with retrospective control group. SETTING: University fertility clinic. PATIENT(S): Patients undergoing IVF and intracytoplasmic sperm injection. INTERVENTION(S): Transabdominal ultrasonographic guidance at embryo transfer. MAIN OUTCOME MEASURE(S): Pregnancy and implantation rates. RESULT(S): In 367 ultrasound-guided embryo transfers clinical PR, ongoing PR, and implantation rate were 35.1%, 31.1%, and 24.3%, respectively. In 363 embryo transfers based on previous ultrasonographic length measurement, the rates were 33.9%, 29.5%, and 24.2%, respectively. There were no statistical significant differences between the groups. CONCLUSION(S): Ultrasonographic guidance does not show any benefit in terms of PR and implantation rate compared to previous ultrasonographic length measurement, an other precise and atraumatic transfer technique.

Adult↗
PubMed2007

Effect of embryo quality on pregnancy outcome following single embryo transfer in women with a diminished egg reserve.

OBJECTIVE: To evaluate independently the effect of blastomere number and degree of fragmentation on pregnancy outcome following single ETs in women with a decreased egg reserve. DESIGN: Retrospective cohort analysis. SETTING: In vitro fertilization center of a university-based practice. PATIENT(S): Women having a single ET related to a decreased egg reserve. A requirement for inclusion was a day 3 serum FSH >12 mIU/mL and < or =3 antral follicles on ultrasound. INTERVENTION(S): Patients received no or minimal stimulation with gonadotropins. MAIN OUTCOME MEASURE(S): Pregnancy rates (PRs) following single ETs were evaluated according to blastomere number (group 1, < or =4 cells; group 2, 5 cells; group 3, 6 cells; group 4, 7 cells; and group 5, > or =8 cells) and fragmentation index (A, no fragmentation; B, 1-25% fragmentation; and C, >25% fragmentation). Embryo transfers and morphologic evaluation were performed on day 3. RESULT(S): The clinical and delivered PRs according to blastomere number showed that 6-8-cell embryos were six times more likely to implant than 4-5-cell embryos (6.6% versus 40.4% clinical). Degree of fragmentation did not predict outcome nearly as well as blastomere number. The overall clinical and delivered PRs per transfer were 27.8% and 24.1%, respectively, and were 14.8% and 12.8% per retrieval, respectively, and were 9.0% and 7.3% per initiated cycle, respectively. CONCLUSION(S): Six, seven, or eight-cell embryos have equal chances of implanting in women with day 3 elevated serum FSH. The key finding is that these embryos do better than those with <6 blastomeres. These data may be helpful in women with a diminished ovarian reserve in attempting IVF with their own eggs or when choosing donor oocytes.

Adult↗
PubMed2004

Luteotrophic influence of early bovine embryos and the relationship between plasma progesterone concentrations and embryo survival.

This study was carried out to evaluate the luteotrophic influence of early (before Day 7 as well as after Day 7; Day 0=estrus) bovine embryos and the relationship between plasma progesterone (P4) concentrations and embryo survival. Virgin Holstein dairy heifers (n=325) from a single herd were randomly allocated to be nonbred, bred by artificial insemination (AI) or by embryo transfer (ET). Bred heifers were either treated with 1500 IU human chorionic gonadotrophin (hCG) on Day 7 of the estrous cycle or received no hCG treatment. Plasma P4 concentrations on Days 0, 5, 7, 10, 13, 15, 17, 19 and 21 were similar in pregnant AI- and ET-bred heifers and, this was observed in both hCG-treated and untreated females. Nonbred, AI- and ET-bred nonpregnant heifers (both hCG-treated and untreated) presented similar plasma P4 concentrations. Plasma P4 concentrations of pregnant heifers significantly deviated from those of nonpregnant and nonbred heifers on Day 17. In hCG-treated heifers, plasma P4 concentrations and Day 28 pregnancy rate were significantly higher in females with an induced accessory corpus luteum (CL) than in those females without an induced accessory CL. Treatment with hCG, although inducing the formation of accessory CL and significantly increasing plasma P4 concentrations had no significant effect on Day 28 pregnancy rate. In conclusion, this study does not support the existence of any peripherally detectable luteotrophic influence from early embryos (Days 5-7). Plasma P4 was only significantly related to embryo survival on Day 17, the time of expected onset of luteolysis.

Animals↗
PubMed2006

Transfer of inner cell mass cells derived from bovine nuclear transfer embryos into the trophoblast of bovine in vitro-produced embryos.

Presence of placental tissues from more normal noncloned embryos could reduce the pregnancy failure of somatic cloning in cattle. In this study, inner cell mass (ICM) cells of in vitro-produced (IVP) embryos was replaced with those of nuclear transfer (NT) embryos to reconstruct bovine blastocysts with ICM and trophoblast cells from NT and IVP embryos, respectively. A total of 65 of these reconstructed embryos were nonsurgically transferred to 20 recipient beef females. Of those, two females were diagnosed pregnant by ultrasonography on day 30 of gestation. One pregnancy was lost at 60-90 days of gestation, and the other recipient cow remained pregnant at day 240 of gestation; however, this female died on day 252 of gestation. Gross pathology of the internal organs of the recipient female, a large fetus, and a large placental tissue mass suggested the massive size of the fetus and placental tissue were likely involved in terminating the life of the recipient female. Biopsy samples were harvested from the skin of the dead recipient cow, the fetus and from cotyledonary tissue. Microsatellite DNA analysis of these samples revealed that the genotype of the fetus was the same as that of the NT donor cells and different from that of the recipient cow. Correspondingly, neither the fetus nor recipient cow had the same genotype with that of the fetal cotyledonary tissue. These results present the first known documented case of a bovine somatic NT pregnancy with nonclone placental tissues after transfer of a blastocyst reconstructed by a microsurgical method to exchange of ICM cells and trophoblast tissue between NT and IVP blastocysts.

Animals↗
PubMed1995

Galileo and the embryos: religion and science in parliamentary debate over research on human embryos.

Confrontation between science and religion was a significant feature of the lengthy public appraisal of research on human embryos in Britain during the 1880s. The series of formal debates over embryo research in the House of Lords is chosen as a particularly appropriate setting to study this confrontation. It is shown that religious opposition to embryo research was repeatedly attacked in these debates by means of a stereotyped contrast between religious and scientific styles of thought. Leading figures in the movement for embryo research attempted to discredit their opponents by claiming that, whereas their own case was built upon reasoned assessment of the facts, the other side relied on religious dogma, clerical authority and faith. It is shown that, although there were genuine differences between those critical of embryo research on religious grounds and those supporting such research on grounds furnished by scientists, this account of the differences is inaccurate: dogma, reliance on authority and faith were as characteristic of the discourse associated with science as they were of that associated with religion. It is argued that these features were not generated by the presence of religious or scientific beliefs as such, but by the struggle between advocates of science and religion for intellectual and moral dominance.

Beginning of Human Life↗
PubMed2001

Pregnancy rates (prs) according to embryo cell number at time of embryo transfer (ET).

PURPOSE: To evaluate pregnancy and implantation rates following fresh and frozen embryo transfer (ET) according to blastomere number. METHODS: A retrospective study from 1/1/97 to 9/30/98 including all cycles with ETs irrespective of age. RESULTS: 65% of fresh transfers had at least one 8-cell embryo vs only 39.6% for frozen ET. The clinical pregnancy and implantation rates were higher when one 8-cell embryo was transferred (64% and 24%) vs a 5-7 cell embryo (41% and 14.5%) for fresh transfers. There was less of a difference with frozen ETs (46% and 19% for 8-cell vs 38% and 17% for 5-7 cell). CONCLUSIONS: Since mostly only 8-cell embryos at day 3 reach the blastocyst stage, these data raise questions as to whether the quest to attain the highest pregnancy rate per transfer through blastocyst transfer, may be at the expense of overall pregnancy rate (fresh and frozen) from a given oocyte harvest.

Adult↗
PubMed2005

[Vitrification of human cleaved embryos in vitro fertilization-embryo transfer].

OBJECTIVE: To assess the outcome of thawing human cleaved embryos from cryopreservation by vitrification. METHODS: A total of 957 day 2 or day 3 embryos from 219 patients were thawed after vitrification with ethylene glycol 5.5 solution and 0.25 ml straw between Jan 2003 and Jun 2005, 514 embryos were recovered and transferred in 178 patients. RESULTS: The survival rate of thawing embryos and the clinical pregnancy rate after transfer was 72.2% and 19.7% respectively. Twenty-two healthy babies were born from 16 deliveries, including 12 girls and 10 boys, 6 pregnancies ended in miscarriage and another 13 are ongoing. CONCLUSION: Vitrification method is an alternative for cryopreservation of human cleaved embryos because of high effectiveness, convenience and good cost efficiency.

Cryopreservation↗
PubMed2006

[Influence of the depth of embryo transfer on pregnancy outcome in in vitro fertilization-embryo transfer].

OBJECTIVE: To detect whether the depth of embryo transfer has influence on pregnancy outcome in in vitro fertilization-embryo transfer (IVF-ET). METHODS: The distance between the high echogenic transfer dot and the fundal endometrium was measured under guidance of transabdominal ultrasound. The average distance 0.75 cm was used to divide patients into two groups. Group 1 included 44 patients with a distance > 0.75 cm, while group 2 had 48 patients with a distance </= 0.75 cm. RESULTS: There were no significant differences in the average age (32 +/- 3 versus 31 +/- 4), the mean number of oocytes retrieved (14 +/- 7 versus 14 +/- 6), and the mean number of embryos transferred (2.3 +/- 0.6 versus 2.2 +/- 0.5) between groups 1 and 2. The distance to the fundal endometrium in group 2 was (0.50 +/- 0.21) cm, significantly smaller than that of group 1 (1.02 +/- 0.21) cm (P < 0.01). However, pregnancy rate was significantly higher (P < 0.05) in group 2 (58.3%, 28/48) than in group 1 (36.4%, 16/44). Although implantation rate in group 2 (33.0%, 35/106) was higher than group 1 (22.2%, 22/99), the difference was not significant. CONCLUSION: Pregnancy outcome may be affected by the depth of embryo transfer, and the fundal endometrium is a favorable region for embryo deposition.

Abdomen↗
PubMed1988

Cultivation of Cryptosporidium baileyi: studies with cell cultures, avian embryos, and pathogenicity of chicken embryo-passaged oocysts.

Sporozoites of Cryptosporidium baileyi did not undergo development in primary cell cultures from either avian or mammalian hosts, or in mammalian cell lines. Oocysts of C. baileyi produced infections resulting in complete development to sporulated oocysts in chicken embryos and embryos of 8 other avian species examined. Inoculation of 4 X 10(5) oocysts was not pathogenic for avian embryos as evidenced by the lack of gross lesions or death. Oocysts obtained after C. baileyi had been passaged 10 times (first experiment) or 20 times (second experiment) in chicken embryos still caused clinical respiratory disease and gross airsacculitis when inoculated intratracheally into 2-day-old broiler chickens. Oocysts that had been passaged 10 times in chicken embryos were similarly pathogenic for 4-day-old turkeys after intratracheal inoculation.

Animals↗
PubMed1981

Effects of varying chamber construction and embryo pre-incubation age on survival and growth of chick embryos in shell-less culture.

Shell-less culture involves culturing chick embryos with associated yolk and albumen outside of the eggshell and shell membranes. The technique allows direct access to and continuous observation of cultured embryos almost to the time of hatching. The plastic wrap/culture tripod technique described in this paper allows normal embryonic growth and differentiation from 48 hours (in ovo pre-incubation age) through at least 10 days of total incubation. As the duration of in ovo pre-incubation is decreased below 36 hours, there is a concomitant increase in the percentage of grossly abnormal embryos associated with decreased survival and retarded growth and differentiation. Survival of embryos pre-incubated for 72 hours through 13 and 18 days of total incubation is greater than 80% and 40%, respectively. The wrap/tripod technique allows substantially better survival and more normal development of cultured embryos than does the petri dish technique of Auerbach et al. (1974). Embryonic growth in 7.8-cm-diameter chambers is significantly greater than in either larger (10.6 cm) or smaller (5.2 cm) diameter chambers. Some gas exchange through the culture chamber walls appears necessary for optimal embryonic survival and growth. Suspending egg contents in either Safeway or Handi-Wrap plastic wrap (both of intermediate permeability) in 7.8-cm tripods resulted in superior growth and/or survival compared to suspension in Silastic sheeting (high permeability), Saran Wrap (low permeability), glass dishes (nonpermeable), or glass dishes lined with an inner layer of Safeway wrap(nonpermeable).

Animals↗
PubMed2002

Dynamic in vivo imaging of postimplantation mammalian embryos using whole embryo culture.

Due to the internal nature of mammalian development, much of the research performed is of a static nature and depends on interpolation between stages of development. This approach cannot explore the dynamic interactions that are essential for normal development. While roller culture overcomes the problem of inaccessibility of the embryo, the constant motion of the medium and embryos makes it impossible to observe and record development. We have developed a static mammalian culture system for imaging development of the mouse embryo. Using this technique, it is possible to sustain normal development for periods of 18-24 h. The success of the culture was evaluated based on the rate of embryo turning, heart rate, somite addition, and several gross morphological features. When this technique is combined with fluorescent markers, it is possible to follow the development of specific tissues or the movement of cells. To highlight some of the strengths of this approach, we present time-lapse movies of embryonic turning, somite addition, closure of the neural tube, and fluorescent imaging of blood circulation in the yolk sac and embryo.

Air↗
PubMed1981

Embryo-derived teratocarcinoma. III. Development of tumors from teratocarcinoma-permissive and non-permissive strain embryos transplanted to F1 hybrids.

Seven-day-old mouse embryos of two teratocarcinoma-permissive (C3H and BALB/c) and two teratocarcinoma-non-permissive (C57BL/6 and AKR) strains were transplanted to their F1 hybrids to determine the role of the genetic background of the recipient animals in controlling embryo-derived teratocarcinogenesis. The yield of teratocarcinomas in F1 hybrid recipients of embryonic grafts was either identical with the yield in syngeneic recipients or increased or decreased, depending on the strain of the embryo and the F1 hybrid combination. In certain hybrids, the yield of malignant tumors remained the same as in the syngeneic recipients but the F1 hybrids exerted a stimulatory effect on tumor growth and the tumors weighed more than those in syngeneic recipients. A matroclinous effect was also seen in certain hybrids. These data indicate that embryo-derived teratocarcinogenesis in histocompatible F1 mice depends on the genetic background of adult recipients. The teratocarcinogenic potential of non-permissive and permissive strain mouse embryos can be modified by choosing appropriate F1 hybrids for embryonic transplantations.

Animals↗
PubMed1988

Improved growth and development of presomite mouse embryos in whole embryo culture.

A rotator whole embryo culture system was used to assess the growth and development of late-primitive-streak-stage (Theiler stage 9-10) mouse embryos to the limb-bud stage of organogenesis in a variety of media containing combinations of mouse serum (MS), rat serum (RS), and Tyrode's buffer (TB). The results demonstrate that embryonic growth and morphogenesis to the early limb-bud stage (20 somite pairs; 48-h total culture period) mimicked that in vivo when embryos were grown for 24 h in combinations of MS:RS:TB 1:2:1 or 2:1:1 (v/v/v) and then were transferred to fresh medium containing RS:TB 3:1 at the early somite stage. When the culture period was extended for an additional 24 h (total 72-h culture period) embryonic growth retardation was observed. Regardless of the medium employed, superior growth was observed in embryos transferred at the early somite stage when compared to embryos cultured continuously in the same medium for the entire 48- or 72-h culture period.

Animals↗
PubMed1995

Effect of donor embryo cell number and cell size on the efficiency of bovine embryo cloning.

To establish reliable criteria for the evaluation of nuclear donor embryos, we studied the effect of cell number and cell size of in vitro produced day 6 donor morulae on the rate of blastocyst formation following nuclear transfer to in vitro matured oocytes. In experiment 1, donor embryos were divided into three groups with low (25-34), intermediate (40-55), and high (60-81) blastomere numbers. Transfer of nuclei from day 6 morulae with intermediate and high cell numbers resulted in a significantly higher blastocyst rate (31% and 32%, respectively) than use of nuclei from day 6 morulae with low cell numbers (17%) or nuclei from day 7 morulae with 50-83 blastomeres (19%). This suggests that blastomeres from the developmentally advanced day 6 morulae are more viable than blastomeres from retarded embryos. In experiment 2, we evaluated the effect of blastomere size in day 6 donor morulae with intermediate (40-55) or high (60-81) cell numbers on the efficiency of nuclear transfer. In both classes of embryos, small blastomeres were better nuclear donors than large blastomeres. The rates of development to the blastocyst stage were 28% versus 15% (40-55 cells) and 41% versus 25% (60-81 cells), suggesting that small blastomeres include a higher proportion of totipotent cells than the polarized large blastomeres. Our results demonstrate that blastomere number and size markedly affect the efficiency of nuclear transfer and therefore are useful criteria for evaluating nuclear donor embryos. These parameters are easy to determine and may therefore be helpful to improve the efficiency of cattle cloning.

Animals↗
PubMed1989

Development of chimaeric two-cell mouse embryos produced by allogenic exchange of single nucleus from two- and eight-cell embryos.

Synchronous or asynchronous chimaeras were produced by transplanting a single nucleus of two- and eight-cell embryos from CD-1xCD-1 or BALB/CxBALB/C albino strains into one enucleated blastomere of a late F1 (C57/BLxCBA) x F1 two-cell embryo. The cytoplasmic volume of the blastomere was reduced in some instances by 50%. These chimaeric embryos were cultured in vitro and transferred to pseudopregnant recipients. The distribution of each component to the pups and to the day-10 embryos after transfer to recipients was determined by examining their coat color and by glucose phosphate isomerase analysis, respectively. The contribution of progeny of the nuclear-transplanted cell with nonreduced cytoplast to the pups was 83% when synchronous; this proportion decreased to 43% when asynchronous because the progeny tended to migrate to the trophoblast and/or to the primitive endoderm. When the recipient cytoplast was reduced by 50%, the contribution of the nuclear-transplanted cell progeny to the pups was 79% when synchronous and 80% when asynchronous. This shows that allogenic exchange of a single nucleus at the two-cell stage by nuclear transfer is an effective procedure for producing highly asynchronous mouse chimaeras and suggests that larger and advanced blastomeres tend to be excluded from the inner cell mass of the embryo, but smaller, advanced blastomeres do not.

Animals↗
PubMed1990

Immunosuppressive activity in human embryo growth media is associated with successful pregnancy: effect of gonadotropin releasing hormone agonist (GnRHa) treatment of patients undergoing in vitro fertilization and embryo transfer (IVF-ET).

The aim of the present study was to determine whether the secretion of embryo-associated immunosuppressor factor (EASF) by preimplantation embryo correlates with pregnancy outcome and whether this relationship is influenced by pretreatment of gonadotropin releasing hormone agonist (GnRHa) in patients undergoing in vitro fertilization and embryo transfer (IVF-ET). EASF activity was measured using concanavalin A-induced human lymphocyte proliferation assay in 256 embryo growth media obtained from 61 patients undergoing IVF-ET. EASF activity was then correlated with GnRHa treatment and pregnancy outcome in these IVF patients. Results indicate that (i) the presence of immunosuppressive activity in human embryo growth media is associated with success of pregnancy in GnRHa nontreated patients and (ii) serum factors present in GnRHa-treated patients may affect the EASF secretion by preembryos in vitro.

Blastocyst↗
PubMed1990

Embryo-derived platelet activating factor, a marker of embryo quality and viability following ovarian stimulation for in vitro fertilization.

Embryo-derived platelet-activating factor (PAF) may be an important mediator of early maternal recognition of pregnancy. PAF was higher in media associated with clinical pregnancies when compared to preclinical pregnancies but not higher in pregnant vs nonpregnant groups. The production of PAF by the preimplantation embryo was not related to follicle size or embryo morphology. However, differences in PAF concentrations in the culture media were related to the age of the embryo culture medium and the developmental stage of the embryo.

Biomarkers↗
PubMed1987

Regulation of intracellular glutathione in rat embryos and visceral yolk sacs and its effect on 2-nitrosofluorene-induced malformations in the whole embryo culture system.

The dysmorphogenic effects of 2-nitrosofluorene (NF) in vitro were modulated in Day 10 rat embryos by agents which regulate intracellular glutathione (GSH) levels. The incidence of abnormal axial rotation caused by NF alone increased in a dose-dependent manner at NF concentrations in excess of 25 microM. No effects were observed at 15 microM NF and doses of 100 microM resulted in a 100% incidence of mortality. L-Buthionine-S,R-sulfoximine (BSO), an inhibitor of GSH synthesis, produced malformations (50%) in embryos exposed to 15 microM NF but produced no additional effects on embryos at higher NF concentrations. BSO treatment alone resulted in a greater than 50% decrease in GSH content in visceral yolk sacs and had a lesser but likewise significant effect (15% decrease) on the GSH content of embryos. Protein content was inversely affected as embryonic levels were increased by 20% and yolk sac levels were unchanged. When BSO was added in combination with NF at the onset of the culture period, embryonic GSH decreased in a dose-dependent manner, suggesting a relatively low rate of embryonic GSH turnover that could be increased by addition of an exogenous substrate capable of forming adducts with and removing GSH from the cells. 2-Oxothiazolidine-4-carboxylate (OTC), a compound which is enzymatically modified to provide an additional source of intracellular cysteine and increase GSH synthesis, produced no significant changes in embryonic or yolk sac GSH when added alone to the culture medium. When OTC (5 mM) was added in combination with NF, however, NF-elicited malformations were eliminated. This was also the case at 100 microM NF in which OTC not only prevented malformations but completely protected embryos against the loss in viability. The GSH and protein levels were indistinguishable from controls when OTC and NF were added simultaneously except for the 41 microM NF dose at which a highly significant increase in both embryonic and yolk sac protein was observed. This study clearly demonstrates the potential importance of GSH in the modulation of chemical dysmorphogenesis and provides an important new tool for the study of mechanisms of developmental toxicity.

Abnormalities, Drug-Induced↗