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At least 433 records · Page 24Linked to original sources
PubMed2005

Influence of embryo quality and number of previous cycles on pregnancy and multiple pregnancy rates in women aged 35 to 37 years who received two or three embryos.

Women aged 35-37 years undergoing IVF-ET with fresh embryos at a university infertility center were analyzed to evaluate factors useful in determining whether two or three embryos should be transferred in this age group. Embryo quality and number, but not number of previous failed cycles, were important in determining outcome, and all triplet pregnancies could have been avoided at our program in this age group by limiting the transfer to two good-quality embryos, without reducing pregnancy rates.

Adult↗
PubMed2006

An alternative simple method for mass production of chimeric embryos by coculturing denuded embryos and embryonic stem cells in Eppendorf vials.

The generation of germline competent chimeric mice via embryonic stem (ES) cells is a crucial step in developing gene-manipulated mouse models. To date, techniques for generating chimeric mice include direct microinjection of ES cells into the cavity of 3.5-d post-coitum (dpc) blastocysts and aggregating or coculturing 2.5 dpc zona pellucida-free (denuded) embryos with ES cells. We present here a procedure that is simple and reproducible for mass producing (10-150 embryos/vial/time) chimeric embryos by coculturing denuded 8-cell embryos and morula in 0.8 mL KSOM-AA medium containing 5 x 10(5)mL-1 purified green fluorescence protein-expressing ES cells (either fresh or thawed) in an 1.7 mL Eppendorf vial for 3h. The resulting chimeras had substantial levels of chimerism and high germline transmission rates. Therefore, the method developed in this study can provide a simple and mass reproducible alternative method (to germline transmitter chimeric mice), without technological and instrumental difficulties, for generating chimeric embryos.

Animals↗
PubMed1998

Production of sheep embryos in vitro and development of progeny following single and twin embryo transfers.

An in vitro culture system for producing ovine embryos is described, in which heat inactivated sheep serum was used as a protein source for maturation, fertilization and 7-d culture phases. Ovaries obtained from a commercial abattoir were used as the source of mature ewe (285) and lamb oocytes (356), which were subsequently cultured in this system to yield similar mean cleavage rates of 91 and 92%, respectively, but significantly different (P < 0.025) proportions for blastocysts/cleaved oocytes (46 and 18%). At Days 7 or 8 of culture, embryos from each source were transferred, either singly (ewe-derived) or in pairs (ewe- and lamb-derived), to hormonally synchronized recipient ewes, resulting in the birth of lambs ranging in weight from 2.5 to 8.8 kg for singletons and 2.6 to 8.0 kg for twins. Mean gestation length of 153.4 +/- 0.5 d (range 151 to 160) was slightly longer than the expected norm of about 150 d. The pregnancy rate was significantly higher after the transfer of embryo pairs (64%) than single (39%) embryos, while survival of lambs to weaning was greater for singleton (80%) than for twin lambs (43%). Some factor(s) in the culture media, such as growth factors in the sera, may have a mitogenic effect on embryonic cells, or it may alter the distribution of cells to the trophectoderm and inner cell mass, resulting in enhanced body growth rates.

Animals↗
PubMed2003

Involvement of interleukin-1 and the interleukin-1 receptor antagonist in in vitro embryo development among women undergoing in vitro fertilization-embryo transfer.

PURPOSE: To examine the roles of Interleukin-1 (IL-1) and IL-1 receptor antagonist (IL-1ra), in in vitro embryo development and subsequent pregnancy outcome. METHODS: Maternal serum utilized to supplement embryo growth in IVF cycles was analyzed for the presence of IL-1 cytokines. RESULTS: The maternal serum that was utilized to supplement the embryo media was found to have measurable amounts of IL-1beta and IL-1ra. CONCLUSIONS: Relative antagonism of the IL-1 system was positively associated with embryo development and pregnancy outcome.

Embryo Transfer↗
PubMed2002

Ex vivo whole-embryo culture of caspase-8-deficient embryos normalize their aberrant phenotypes in the developing neural tube and heart.

Caspase-8 plays the role of initiator in the caspase cascade and is a key molecule in death receptor-induced apoptotic pathways. To investigate the physiological roles of caspase-8 in vivo, we have generated caspase-8-deficient mice by gene targeting. The first signs of abnormality in homozygous mutant embryos were observed in extraembryonic tissue, the yolk sac. By embryonic day (E) 10.5, the yolk sac vasculature had begun to form inappropriately, and subsequently the mutant embryos displayed a variety of defects in the developing heart and neural tube. As a result, all mutant embryos died at E11.5. Importantly, homozygous mutant neural and heart defects were rescued by ex vivo whole-embryo culture during E10.5-E11.5, suggesting that these defects are most likely secondary to a lack of physiological caspase-8 activity. Taken together, these results suggest that caspase-8 is indispensable for embryonic development.

Animals↗
PubMed2001

From cell death to embryo arrest: mathematical models of human preimplantation embryo development.

Human preimplantation embryos exhibit high levels of apoptotic cells and high rates of developmental arrest during the first week in vitro. The relation between the two is unclear and difficult to determine by conventional experimental approaches, partly because of limited numbers of embryos. We apply a mixture of experiment and mathematical modeling to show that observed levels of cell death can be reconciled with the high levels of embryo arrest seen in the human only if the developmental competence of embryos is already established at the zygote stage, and environmental factors merely modulate this. This suggests that research on improving in vitro fertilization success rates should move from its current concentration on optimizing culture media to focus more on the generation of a healthy zygote and on understanding the mechanisms that cause chromosomal and other abnormalities during early cleavage stages.

Apoptosis↗
PubMed1977

Developmental decline in DNA repair in neural retina cells of chick embryos. Persistent deficiency of repair competence in a cell line derived from late embryos.

Neural retinas of 6-day-old chick embryos synthesize DNA and are able to carry out DNA excision repair. However, in contrast to the situation in human cells, the maximum rate of repair induced by N-acetoxy acetylaminofluorene (AAAF) is no greater than that induced by methyl methanesulfonate (MMS). With advancing differentiation of the retina in the embryo, cell multiplication and DNA synthesis decline and cease, and concurrently the cells lose the ability to carry out DNA excision repair. Thus, in 15-16-day embryos, in which the level of DNA synthesis is very low, DNA repair is barely detectable. If retinas from 14-day embryos are dissociated with trypsin and the cell suspension is plated in growth- promoting medium, DNA synthesis is reinitiated; however, in these cultures there is no detectable repair of MMS-induced damage, and only low levels of repair are observed after treatment with AAAF. A cell line was produced, by repeated passaging of these cultures, in which the cell population reached a steady state of DNA replication. However, the cell population remained deficient in the ability to repair MMS-induced damage. This cell line most likely predominantly comprises cells of retino-glial origin. Possible correlations between deficiency in DNA repair mechanisms in replicating cells and carcinogenesis in neural tissues are discussed.

Acetoxyacetylaminofluorene↗
PubMed2001

PAF receptor and PAF acetylhydrolase expression in the endosalpinx of the human Fallopian tube: possible role of embryo-derived PAF in the control of embryo transport to the uterus.

BACKGROUND: Prostaglandin-E(2) and platelet-activating factor (PAF) are embryonic-derived signals that time embryo passage into the uterus in the mare and hamster respectively. PAF-like activity is detectable in the spent media of preimplantation human embryos and it has been suggested that PAF may be the embryonic signal that controls embryo transport to the uterus in our species. The actions of PAF are regulated at the level of its synthesis and degradation as well as the expression of a specific cell surface receptor (PAFr). The enzyme PAF acetylhydrolase (PAF-AH) degrades PAF. This study was undertaken to examine whether or not PAFr and PAF-AH are expressed in the human Fallopian tube and to identify the cell types in which they are expressed. METHODS: The presence of PAFr mRNA in tissue extracts was investigated using reverse transcription-polymerase chain reaction. We amplified the predicted amplicon for PAFr mRNA from RNA samples extracted from Fallopian tubes. The expression of PAF-AH was detected by Western blot and the localization of PAFr and PAF-AH proteins was detected by immunohistochemistry. RESULTS: Utilizing antibodies against PAFr and PAF-AH, co-localization of the two proteins in the epithelium and stromal cells were demonstrated. CONCLUSIONS: These observations show that the human Fallopian tube expresses PAFr and PAF-AH at a location compatible with the proposed paracrine role of early embryo-derived PAF.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2004

A real-life prospective health economic study of elective single embryo transfer versus two-embryo transfer in first IVF/ICSI cycles.

BACKGROUND: We analysed the difference in maternal, neonatal and total costs after single (SET) versus double day 3 embryo transfer (DET). METHODS: We performed a two-centre prospective study of women in their first IVF/ICSI cycle choosing between SET or DET. Infertility treatment data were gathered from a database; maternal and neonatal outcome data from a case report form (CRF); health economic data from medical acts registered in the CRF for the outpatient part and from hospital bills. SET was performed in 206/367 (56.1%) and DET in 161/367 (43.9%) women. RESULTS: In all, 367 transfers yielded 186 positive pregnancy tests, 148 ongoing pregnancies and 136 live deliveries (50.7, 40.3 and 37.1% per embryo transfer) of which 15 (11.0%) were twins. Live birth rate was 37.4% for SET, 36.6% for DET. Intention-to-treat analysis showed differences for: duration of pregnancy (SET: 39.0 +/- 1.4 versus DET: 38.3 +/- 2.2 weeks; P = 0.055), percentage prematurity (8.5 versus 23.8%; P = 0.033), percentage of neonates hospitalized (5.7 versus 17.9%; P = 0.121) and duration of neonatal hospitalization (6.3 +/- 2.2 versus 10.3 +/- 10.1 days; P = 0.01). Total cost after DET was higher (SET: 4700 +/- 3239 versus DET: 8613 +/- 10 105; P = 0.105), due to significantly higher neonatal costs (451 +/- 957 versus 3453 +/- 8154; P < 0.001) and not to differences in maternal costs (4250 +/- 2882 versus 5160 +/- 4106; P = 0.152). CONCLUSIONS: This prospective health economic study shows that transfer of a single top quality embryo is equally effective as, but substantially cheaper than, double embryo transfer in women <38 years of age in their first IVF/ICSI cycle.

Birth Rate↗
PubMed1990

The effect of iron and iron chelators on the in-vitro block to development of the mouse preimplantation embryo: BAT6 a new medium for improved culture of mouse embryos in vitro.

The effect of iron and iron chelators on the development of the mouse embryo in vitro from the 1-cell stage to the blastocyst has been investigated. An adverse effect of iron was found. The high affinity iron chelator, desferal, also blocked development, whilst transferrin (whether as apoprotein or saturated with iron), DETAPAC and EDTA promoted development. The addition of transferrin permitted development to the blastocyst stage of embryos from stains normally exhibiting the 2-cell block. Under such circumstances both the rate of embryonic development and the proportion of embryos reaching the blastocyst stage approached levels found in vivo. Based on these results, a new medium, BAT6, is described for the optimal in-vitro culture of mouse embryos.

Animals↗
PubMed2001

Embryo growth and amino acid concentration profiles of broiler breeder eggs, embryos, and chicks after in ovo administration of amino acids.

Two experiments were conducted to evaluate the effect of in ovo amino acid (AA) injections in broiler breeder eggs on AA utilization of embryos. All AA used in these experiments were pure crystalline AA in free-base form. Treatments in Experiment 1 comprised 1) control eggs (no injection), 2) 0.5 mL sterile-distilled water injected eggs, and 3) eggs injected with an AA solution suspended in 0.5 mL sterile-distilled water. Injections were administered into the yolk at Day 7 of incubation. At hatch, chicks were killed and bled, and plasma AA concentration was determined. Plasma AA concentration of hatched chicks decreased (P < 0.05) when water was injected. In addition, all AA from eggs injected with AA, except Glu and Lys, were decreased (P < 0.05) at hatch as compared to control eggs. However, AA pattern was not affected by in ovo water injection, but the AA ratio to Lys was reduced by in ovo AA injection. Experiment 2 was conducted to evaluate whole internal egg AA concentrations over incubation time in the presence or absence of in ovo AA administration. Treatments in Experiment 2 comprised 1) control eggs (no injection), and 2) eggs injected with a AA solution at Day 7 of incubation. The AA contents of embryo, yolk, albumen, and allantoic and amnion fluids were analyzed over time during incubation (Days 0, 7, 14, and 19 of incubation). On Day 14 of incubation, there were no differences in AA contents of all tissues between the control group and the group injected with AA on Day 7 of incubation. On Day 19 of incubation, AA contents of embryo, yolk, albumen, and allantoic and amnion fluids were increased (P < 0.05) as mediated by in ovo administration of AA at Day 7 of incubation. These results suggest that in ovo administration of AA may increase AA concentrations in chicken embryos and other egg contents.

Amino Acids↗
PubMed1998

Nuclear-cytoplasmic interaction and development of goat embryos reconstructed by nuclear transplantation: production of goats by serially cloning embryos.

The time of pronuclear formation of in vivo-matured oocytes was examined. Maturation-promoting factor (MPF) activity in enucleated and electrically activated oocytes was checked by assessment of nuclear envelope breakdown (NEBD) of fused blastomeres. The effect of stage of the cell cycle of donor cells and recipient oocytes on DNA synthesis and development of reconstructed embryos was studied. MPF activity declined rapidly to approximately 63.2% at 1 h, to 9.7% at 5 h, and to the level at which NEBD cannot occur at 7 h postactivation. All blastomeres that were fused at the time of recipient cytoplasm activation underwent NEBD and subsequent DNA synthesis. However, when blastomeres were fused to enucleated oocytes at 7 h postactivation, no NEBD was observed; DNA was replicated in nuclei at the G1/S border, but in G2 nuclei no DNA replication was observed. The proportion of development to blastocysts of reconstructed goat embryos increased with the decline in MPF activity in fused recipient cytoplasm when reconstruction took place at 0-6 h postactivation of enucleated oocytes. Generations 1, 2, 3, 4, 5, and 6 of cloned goat embryos were produced by a combination of nuclear transplantation and in vitro techniques. After transfer to recipients, 45 kids were obtained, including three pairs of monozygotic twins, three series of monozygotic triplets, two series of monozygotic quadruplets, three series of monozygotic quintuplets, and one series of monozygotic heptaplets. The present study indicates that normal DNA replication of goat blastomere nuclei can be accomplished in enucleated oocytes when MPF activity is low, regardless of the stage of the cell cycle of donor nuclei; induction of NEBD and prematuration chromosome condensation is not essential for further development of reconstructed goat embryos.

Animals↗
PubMed2005

Wound healing ability of Xenopus laevis embryos. I. Rapid wound closure achieved by bisectional half embryos.

We examined wound closure in 'half embryos' produced by the transverse bisection of Xenopus laevis embryos at the primary eye vesicle stage. Both the anterior- and posterior-half embryos survived for more than 6 days, and grew into 'half tadpoles'. Histology and videomicroscopy revealed that the open wound in the half embryo was rapidly closed by an epithelial sheet movement in the wound marginal zone. The time-course of wound closure showed a downward convex curve: the wound area decreased to one-fifth of the original area within 30 min, and the wound continued to contract slowly thereafter. The rapidity of closure of the epidermis as well as the absence of inflammatory cells are typical features of an embryonic type of wound healing. There was a dorso-ventral polarity in the motility of the epidermis: the wound was predominantly closed by the ventral and lateral epidermis. The change in the contour of the wound edge with time suggested a complex mechanism involved in the wound closure that could not be explained only by the purse-string theory. The present experimental system would be a unique and useful model for analyses of cellular movements in the embryonic epithelia.

Animals↗
PubMed1989

Twin embryos in mares. II: Post fixation embryo reduction.

Recent findings on the development and natural outcome of twins from Day 17 (immediately after fixation) to Day 40 are reviewed. Incidence of embryo reduction was increased significantly when the vesicles became fixed unilaterally, rather than bilaterally, and when the vesicles were unequal in diameter. Of 68 mares with twins on the day of fixation, post fixation embryo reduction occurred in 41 (60 per cent). The incidence of reduction was 41 of 48 (85 per cent) following unilateral fixation; reduction occurred in all of 22 mares with vesicles of dissimilar size (4 mm or more difference in diameter) and in 19 (73 per cent) of 26 mares with vesicles of similar size (0 to 3 mm difference). Embryo reductions were complete (vesicle no longer visible ultrasonically) by Day 20 (59 per cent of the reductions), during Days 21 and 30 (27 per cent), or Days 31 to 38 (14 per cent). In 80 per cent of the early reductions (by Day 20) the eliminated vesicle disappeared within one day. Reductions that occurred after Day 20 were preceded by a gradual decrease in size. As the number of days after Day 17 increased, the frequency of reduction decreased and the time required for completion of reduction increased. When the twins were dissimilar in diameter (4 mm or more), they were more likely to undergo reduction by Day 20. In summary, dissimilarity in diameter increased the likelihood of unilateral fixation, increased the incidence of reduction for unilaterally fixed vesicles, hastened the day of occurrence of reduction and shortened the interval from initiation to completion of reduction. The deprivation hypothesis proposes that embryo reduction occurs when a major portion of the three walled area of the yolk sac or the vascularised wall of the yolk sac or allantoic sac is in apposition with the wall of the adjacent vesicle rather than with the endometrium; the vesicle is deprived of adequate embryonal-maternal exchange and therefore regresses.

Animals↗
PubMed1993

Development to the blastocyst stage of pig embryos cultured in the amniotic fluid of developing chick embryos.

Early-stage pig embryos were collected from superovulated donor gilts (60-72 hr post hCG injection) and co-cultured in modified Brinster medium for ovum culture (mBMOC-2) + porcine oviduct epithelial cells (POEC) or in the amniotic fluid of a developing chick embryo (CEAm). The development rate to the compacted morulae or blastocyst stage was significantly higher (P < 0.01) in embryos co-cultured in CEAm (60.0%) than those co-cultured in mBMOC-2 + POEC (18.0%). The results indicate that CEAm could be used for production of compacted morulae or blastocysts from early-stage pig embryos. This culture system could also be valuable in situations where a CO2 controlled incubator is not available.

Amniotic Fluid↗
PubMed1993

Patterns of integration and expression of retroviral, non-replicative vectors in avian embryos: embryo developmental stage and virus subgroup envelope modulate tissue-tropism.

We previously demonstrated that Avian Leukemia Viruses (ALV) carrying the v-myc gene specifically induce two types of tumors, cardiomyocytic tumors when the virus is injected before embryonic day 3 (E3), skin tumors when the virus is injected at E3 or E5. Aiming to elucidate the mechanisms which determine this time-dependent change in target, we infected chick and quail embryos at E3 and E5 with replication-deficient, lacZ gene-carrying, ALV-based viruses produced by a packaging cell line. Three constructs driven by 3 different Long Terminal Repeats (LTRs) were tested and yielded similar results. When the constructs were inoculated at E3 and the lacZ gene product revealed 5 days later, around 70% of the embryos carried lacZ+ clones in the heart, around 50% had positive clones in the skin anywhere on the body, while a few embryos displayed clones in internal organs (liver, stomach, lungs). Immunocytological identification of the heart cell type(s) expressing the virus revealed that the only cells infected were cardiomyocytes. When the constructs were inoculated at E5, no lacZ+ clones appeared in the heart but all were located in the cephalic skin. In order to examine the relationship between viral integration and expression, DNA of different organs or tissues from lacZ stained embryos was analyzed by PCR. A tight correlation between integration and expression in the heart and in the skin was revealed in most cases. In contrast, a significant PCR signal was often detected in the liver or the stomach despite weak or absent expression as revealed by lacZ+ clones. We then investigated the influence of envelope glycoprotein subgroups on the tropism of these constructs. The lacZ vector driven by RAV-2 LTRs was packaged as subgroups A, B or E viral particles. The A subgroup, used in the part of the study described above, infects both chick and quail while the B and E subgroups are specific for chick or quail respectively. These B and E subgroups induced lacZ+ clones in the heart (after E3 injection) while no clones or only a few were detected in the skin either after E3 or E5 injection. The following conclusions can be drawn: 1) cardiomyocytes are at E3 the major target for integration and expression of ALV-derived viruses in vivo; 2) targets change rapidly with embryonic age; and 3) tissue-specific infections depend on the envelope subgroup, thus presumably on the presence of the cognate receptor.(ABSTRACT TRUNCATED AT 400 WORDS)

Alpharetrovirus↗
PubMedDate not supplied

Conception and realization of artificial dyed embryos for training in in vitro fertilization and embryo transfer (IVF and ET).

An artificial embryo model is proposed for current training in in vitro fertilization and embryo transfer. It consists in resin microballs of 180 micron diameter, stained either with fluoresceinamin or methylene blue. These microspheres release, even at the maximum dye concentrations tested, very negligible amounts of dye; heat stable they can be sterilized. This model, already checked for human embryo transfer, seems to be a useful tool in other reproduction studies such as embryo transport.

Education, Medical, Continuing↗
PubMed1997

Investigations into mechanisms of amino acid supply to the rat embryo using whole-embryo culture.

The technique pioneered by D.A.T. New for the in vitro culture of early post-implantation rat embryos has been used to study nutritional mechanisms during early organogenesis. The results indicate that the principal route for amino acid supply to the 8.5- to 11.5-day embryo involves the endocytosis of proteins into cells of the visceral yolk sac endoderm, their digestion in lysosomes, and transmission of the amino acids to the growing embryo. Free amino acids constitute a comparatively unimportant source. Inhibition of either endocytosis or intralysosomal proteolysis diminishes amino acid supply to the embryo, and this can result in embryonic death or maldevelopment during organogenesis.

Amino Acids↗