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Results for “embryo assessment”

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At least 19 recordsLinked to original sources

PubMed2006

Sequential embryo assessment outperforms investigator-driven morphological assessment at selecting a good quality blastocyst.

Two selection methods (morphology-only and a sequential embryo assessment algorithm) were compared within the same IVF clinic to determine which method best identifies the embryos on day 3 that will develop into the highest quality on day 5. The sequential embryo assessment algorithm was significantly better at selecting the best embryo and selecting a blastocyst compared with the morphology-only method.

Adult↗

PubMed2005

Noninvasive methods to assess embryo quality.

PURPOSE OF REVIEW: The present review examines recent publications concerned with the issue of the number of embryos to replace in an in-vitro fertilization cycle and in doing so concentrates on the proposed selection methods that may allow us to transfer one or two embryos. RECENT FINDINGS: A number of techniques that will allow us to ascertain the health and viability of the embryo are discussed. These range from methods to assess embryo morphology to those that require more complex forms of technology. Logically the use of the simple methodology is more abundant. However, there is accumulating evidence that some of the more complex assessment techniques may be ready for a more general use. SUMMARY: In performing embryo selection we need to develop processes that will be extremely critical, allowing us to limit the number of embryos replaced without detriment to pregnancy rates.

Cell Nucleus↗

PubMed2026

Non-invasive embryo assessment: Cell-free DNA-based genetic testing and amino acid metabolomics in relation to morphology: A case-control study.

BACKGROUND: Cell-free DNA (cfDNA) in spent culture medium (SCM) offers a non-invasive option for preimplantation genetic testing, but its low concentration and fragmentation reduce clinical reliability. Combining genetic assessment with metabolomic profiling may provide complementary information about embryo competence. OBJECTIVE: This study assessed pre-analytical cfDNA processing workflows and examined whether SCM amino acid metabolic patterns could act as practical markers of embryo quality. MATERIALS AND METHODS: In this case-control study (2021-2023), 90 embryos were evaluated using fluorescence in situ hybridization or array comparative genomic hybridization. SCM samples underwent rapid boiling, silica-based purification, or whole-genome amplification (WGA). Sex determination was performed using quantitative polymerase chain reaction (qPCR). For cfDNA quality control and aneuploidy screening, the multiplex IRFiling kit and quantitative fluorescent polymerase chain reaction (QF-PCR) were used. Amino acid profiles across embryonic developmental stages and quality grades were quantified via liquid chromatography-tandem mass spectrometry. RESULTS: Rapid boiling resulted in complete failure of DNA amplification. Conversely, silica-based purification yielded 70.0% concordance for qPCR-based sexing and 56.7% for QF-PCR. WGA achieved the highest efficacy (73.3% qPCR and 56.7% QF-PCR concordance), although quality control checks flagged occasional misclassifications. LC-MS/MS profiling revealed significantly elevated alanine and arginine levels in tripronuclear embryos. Furthermore, high-quality blastocysts exhibited elevated glutamic acid levels alongside a pronounced overall depletion of extracellular amino acids compared to low-quality counterparts and controls. CONCLUSION: WGA improves cfDNA detectability and qPCR accuracy compared with boiling or purification, but remains inadequate as a standalone screening approach. SCM amino acid profiling provides informative, complementary metabolic signatures of developmental competence, supporting a multimodal strategy for non-invasive embryo assessment.

Amino acid metabolism↗

PubMed2006

Development of a respirometric biochip for embryo assessment.

A prototype respirometric biochip dedicated to monitoring oxygen consumption of preimplantation embryos has been developed. The biochip comprises a linear array of eight flow-through microchambers profiled on silicon substrate, and functions together with a phosphorescent oxygen sensitive probe and fluorescence plate reader detection. A high level of sensitivity to changes in dissolved oxygen was achieved through miniaturisation and optimization of biochip geometry, and incorporation of appropriate sealing and humidification systems. The biochips have allowed characterisation of oxygen consumption, by 2 cell and blastocyst stage preimplantation mouse embryos, through monitoring as few as ten preimplantation embryos over a one-hour time period. They provide a non-invasive, simple and convenient means for assessing preimplantation embryo metabolism.

Animals↗

PubMed1987

Non-invasive methods for assessing embryos.

Non-invasive methods offer considerable potential in assessing the viability of human embryos conceived by IVF. Their use in diagnosing genetic defects appears to be more limited at the present time, but it would be premature to rule out this possibility.

Animals↗

PubMed1995

Nuclear transfer in the bovine using microinjected donor embryos: assessment of development and deoxyribonucleic acid detection frequency.

Bovine embryos that had been microinjected with DNA were examined for their potential use as donor embryos in nuclear transfer. Donor embryos were obtained from oocytes collected by transvaginal oocyte aspiration, matured and fertilized in vitro, microinjected with a murine whey acidic protein-human protein C genomic DNA construct, and cultured in vitro on liver cells of buffalo rat (Rattus norvegicus). Blastomeres from these embryos were transferred into enucleated bovine oocytes received from an abattoir by electrofusion at 40 h postmaturation. Following 7 d of culture, the developmental stage was recorded, and resulting embryos were prepared for analysis by polymerase chain reaction. Embryos that were derived from microinjected donor embryos did not differ from control donor embryos (11 vs. 8.6%) in development to the morula and blastocyst stage. Of the biopsies from 20 microinjected donor embryos, 19 were positive for the injected DNA. Of 37 embryos developing normally, only 12 (32.4%) were positive for the injected DNA. These results indicate that microinjected embryos can be successfully used in a nuclear transfer program to produce additional viable embryos and that these embryos may be reliably screened for the transgene for transfer to recipients.

Animals↗

PubMed1986

Nuclear transplantation in mouse embryos: assessment of recipient cell stage.

Enucleated zygotes were compared with enucleated two-cell embryos as recipients for donor nuclei from eight-cell embryos. Only one or two cleavage divisions were observed when eight-cell nuclei were transplanted to enucleated zygotes. Development of enucleated two-cell embryos containing a transplanted eight-cell nucleus was appreciably better with 51% (45/89) of the embryos forming blastocysts in vitro and 42% (25/60) initiating implantation. Of these, eleven implantation sites on Day 10 of gestation were examined histologically and two contained normally developing embryos. No development was observed beyond Day 12 of gestation. These observations indicate that a major transition occurs between the zygote and two-cell stage that results in the two-cell recipient being more compatible with the eight-cell nucleus than with the zygote.

Animals↗

PubMed1987

Nuclear transplantation in the bovine embryo: assessment of donor nuclei and recipient oocyte.

Blastomeres from 2- to 32-cell bovine embryos were transferred to enucleated oocytes matured either in vivo or in vitro by micromanipulation and electrofusion. The percentage of donor cells fusing with the recipient oocytes was dependent on relative cell size or stage of development. Therefore, when smaller donor karyoplasts (17- to 32-cell vs. 2- to 8-cell) were transferred, the rate of fusion was significantly less (p less than 0.01). After fusion, nuclear transfer embryos were cultured either in vitro or in vivo (in a ligated ovine oviduct). Nuclear transfer embryos cultured in vitro developed to the 4- to 6-cell stage after 72 h (4-cell, 71%; 8-cell, 33%, 16-cell, 33%; p less than 0.30), whereas nuclear transfer embryos cultured in vivo developed to the morula or blastocyst stage (2- to 8-cell, 11.7%; 9- to 16-cell, 16.0%; 17- to 32-cell, 8.3%; p greater than 0.30) after 4 or 5 days. Freshly ovulated oocytes (collected 36 h after the onset of estrus), when used as recipients, resulted in morula/blastocyst-stage embryos more often than in vitro-matured oocytes or in vivo-matured oocytes collected 48 h after the onset of estrus (20% vs. 7.8% and 6.7%, respectively; p less than 0.02). After in vivo culture, nuclear transfer embryos were mounted and fixed or transferred nonsurgically to the uteri of 6- to 8-day postestrus heifers. Seven pregnancies resulted from the transfer of 19 embryos into 13 heifers; 2 heifers completed pregnancy with the birth of live calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Nuclear transplantation in mouse embryos: assessment of nuclear function.

Enucleated mouse zygotes receiving eight-cell nuclei rarely develop beyond the two-cell stage, whereas enucleated two-cell embryos with eight-cell nuclei develop to blastocysts, and a few develop to midgestation. In this study the function of eight-cell nuclei in either the zygote or two-cell recipient was assessed by monitoring several nuclear-dependent events. These included methionine uptake, qualitative changes in protein synthesis, the time of blastocoele formation, and changes in nuclear volume. Although enucleated zygotes with nuclei from eight-cell embryos did not develop past the two-cell stage and had abnormally low levels of methionine uptake, they did show a normal zygote-to-two-cell transition in the types of polypeptides synthesized. Enucleated two-cell embryos with eight-cell nuclei formed blastocysts on schedule with the recipient cell stage and reached levels of methionine uptake equivalent to control embryos. The types of proteins synthesized by two-cell embryos with eight-cell nuclei indicated that the nucleus was developing partly in accord with its own developmental program. Transplanted nuclei did not enlarge to acquire the volume of the recipient cell's nucleus in either the zygote or the two-cell recipient. These results indicate that the difference in development between zygotes and two-cell embryos (each with eight-cell nuclei) may be the result of a greater overlap of function between the two-cell and eight-cell stages, rather than the extent of nuclear reprogramming. Nuclear function was not completely normal in either type of embryo, which may explain their failure to develop to term.

Animals↗

PubMed2001

Use of a non-contact, infrared laser for zona drilling of mouse embryos: assessment of immediate effects on blastomere viability.

To compare the effects of using a non-contact infrared laser with acid Tyrode's for zona drilling, mouse embryos were used to examine both immediate effects on blastomere viability, using fluorescent markers, and development to the blastocyst stage in vitro. Preliminary experiments with isolated blastomeres established that the safe working distance for the lowest setting of the laser (pulse duration 5 ms) was 8 micro m. At the 2-cell stage, when it was possible to drill through the zona while maintaining this safe distance from adjacent blastomeres, no immediate damage was detected. At the 8-cell stage, blastomeres are generally <8 micro m away from the outer surface of the zona and often touch its inner surface. Hence it was not possible to drill the zona while maintaining a safe distance and as a consequence almost all embryos had at least one, and often more, damaged blastomeres. Acid Tyrode's drilling also frequently lysed an adjacent blastomere at this stage and after 24 h in culture cavitation was delayed compared with laser-drilled embryos. Cell numbers at the late morula/early blastocyst stage, analysed by differential labelling of trophectoderm and inner cell mass nuclei, were significantly reduced following zona drilling. With the laser-drilled embryos, this was in proportion to the immediate effects on blastomere viability, whereas with acid Tyrode's, the reduction was greater, indicating an adverse effect on cleavage rate. It is concluded that use of a non-contact laser, at an appropriate pulse duration and distance from adjacent blastomeres, avoids blastomere lysis and adverse effects on development caused by acid Tyrode's zona-drilling.

Journal Article↗

PubMed1998

Restitution of functional neural connections in chick embryos assessed in vitro after spinal cord transection in Ovo.

Functional neural reconnection is not common after spinal cord transection in the CNS of adult higher vertebrates but has been demonstrated in embryonic avian and neonatal mammalian CNS. Chick brainstem spinal cord preparations from nontransected controls and embryos transected at the cervical level on embryonic days (E) 8, 9, or 10 in ovo were assessed in vitro between E12 and E20 for their ability to produce and maintain episodic motor activity (EMA) using electrophysiological, voltage sensitive dye and anatomical tract-tracing techniques. After 3 to 4 days recovery, cycle-by-cycle coupling of EMA between segments separated by a transection was absent or inconsistent, although otherwise normal bouts of locally stimulated and spontaneous EMA were routinely observed restricted to segments of a cord separated by a transection site. After 5-7 days recovery in ovo the cross-transection coordination during bouts of EMA approached that of nontransected controls. The delay between the initiation of EMA in cervical segments to its initiation in lumbosacral segments caudal to a transection was an indicator of reconnection strength. The delay shortened from 0.5 to a few seconds after 3 days of recovery to around 150 ms (i.e., normal) after 5 days of recovery. We conclude that the reconnection of spinal central pattern generators for EMA across the transection was served mainly by axons which established connections with local circuits after extending 1-3 segments through a transection. Propriospinal axons that originated within 1-3 segments rostral to the transection then served to serially initiate EMA in distal caudal segments.

Animals↗

PubMed2004

A successful model to assess embryo development after transplantation of prophase nuclei.

BACKGROUND: Germinal vesicle transplantation (GVT) provides a means of investigating interactions between karyoplasts and cytoplasts isolated from different cells. Technically, GVT can be accomplished with a high degree of efficiency without compromising the maturation of either the human or mouse oocyte nucleus. Although maturation, fertilization and preimplantation development have been established using GVT, full-term development has been reported only after supplementation with fresh mature ooplasm. In this study, we assess the ability of immature oocytes collected from gonadotrophin-primed ovaries to mature in vitro after GVT and develop to full-term. METHODS: GV oocytes were retrieved from either non-stimulated or pregnant mare's serum gonadotrophin (PMSG)-primed female mice. Microsurgically isolated GV karyoplasts were transplanted into previously enucleated oocytes. Oocytes successfully reconstituted by electrofusion were cultured for 14 h to allow nuclear maturation. Metaphase II oocytes were subjected to Piezo-ICSI, and those fertilized normally were cultured to the blastocyst stage. Some such embryos were transferred to pseudopregnant female mice to examine their potential for normal development. Cumulus-denuded non-manipulated oocytes that were matured in vitro served as controls. RESULTS: The reconstitution and maturation rates were comparable in oocytes isolated from PMSG-primed and from unstimulated ovaries. The rate of normal fertilization in oocytes from primed ovaries was significantly higher than that of their non-primed counterparts (63.5 versus 39.6%; P < 0.01). This difference was also confirmed in terms of blastocyst development (31.8 versus 7.9%; P < 0.01). Of a total of 70 embryos transferred to the oviduct of five recipient mice, 21.4% developed to normal live offspring. All developed as normal adults and proved to be fertile. The live birth rate was comparable to that obtained using non-manipulated control oocytes (22.3%). CONCLUSIONS: Higher rates of fertilization and blastocyst formation were obtained after GVT of mouse oocytes isolated from PMSG-primed ovaries compared with their non-primed counterparts. These represent the first mouse offspring derived from in vitro matured, cumulus-denuded oocytes treated by allo-GVT and fertilized by ICSI. Thus, GVT appears not to impair oocyte maturation, fertilization and pre- and post-implantation development and, after gonadotrophin priming, allows generation of healthy mouse offspring without mature ooplasm supplementation.

Animals↗

PubMed2005

The fate of human malignant melanoma cells transplanted into zebrafish embryos: assessment of migration and cell division in the absence of tumor formation.

Certain aggressive melanoma cell lines exhibit a dedifferentiated phenotype, expressing genes that are characteristic of various cell types including endothelial, neural, and stem cells. Moreover, we have shown that aggressive melanoma cells can participate in neovascularization in vivo and vasculogenic mimicry in vitro, demonstrating that these cells respond to microenvironmental cues and manifest developmental plasticity. To explore this plasticity further, we transplanted human metastatic melanoma cells into zebrafish blastula-stage embryos and monitored their behavior post-transplantation. The data show that human metastatic melanoma cells placed in the zebrafish embryo survive, exhibit motility, and divide. The melanoma cells do not form tumors nor integrate into host organs, but instead become scattered throughout the embryo in interstitial spaces, reflecting the dedifferentiated state of the cancer cells. In contrast to the fate of melanoma cells, human melanocytes transplanted into zebrafish embryos most frequently become distributed to their normal microenvironment of the skin, revealing that the zebrafish embryo contains possible homing cues that can be interpreted by normal human cells. Finally, we show that within the zebrafish embryo, metastatic melanoma cells retain their dedifferentiated phenotype. These results demonstrate the utility of the zebrafish embryonic model for the study of tumor cell plasticity and suggest that this experimental paradigm can be a powerful one in which to investigate tumor-microenvironment interactions.

Animals↗

PubMed1998

Asymmetric mRNA expression in the retinal neuroepithelium of the chick embryo assessed by differential display polymerase chain reaction.

In the normal retinotectal topography established during the embryonic development of the chick visual system, retinal ganglion cell axons from the nasal retina connect to the posterior part and temporal retinal axons connect to the anterior part of the optic tectum. For the investigation of position-specific gene expression along the nasal-temporal axis of the retinal neuroepithelium (RN), differential display PCR was carried out from the nasal or temporal part of the RN at HH11 (E2). We found several genes that are differentially expressed either in the nasal or in the temporal part of the RN and the analysis of the asymmetrically expressed fragments showed at least one cDNA fragment to be exclusively expressed in the nasal RN. This fragment was 550 bp in size.

Animals↗

PubMed1980

The use of fluorescein diacetate to assess embryo viability in the mouse.

Preimplantation mouse embryos that were exposed to fluorescein diacetate (FDA) accumulated intracellular fluorescein and fluoresced brightly under ultraviolet (u.v.) light. The rate at which intracellular fluorescein was lost from the cells was measured at 37, 28 and 4 degrees C and the rate decreased as the storage temperature decreased. The rate at which intracellular fluorescein accumulated increased as FDA concentration increased until a maximum rate was attained. The ability to accumulate intracellular fluorescein could be removed by heating embryos at 56 degrees C for 30 min or by damaging the cell membrane. Cells grown under inadequate culture conditions lost the ability to accumulate intracellular fluorescein. Exposure of 2-cell mouse embryos to FDA and u.v. light did not alter the rate of blastocyst formation in vitro, and exposure of blastocysts to FDA and u.v. light did not alter the rate of implantation or post-implantation development in vivo.

Animals↗

PubMed2006

Interobserver agreement and intraobserver reproducibility of embryo quality assessments.

BACKGROUND: The objective of this investigation was to determine the inter- and intraobserver agreement when assessing embryo quality. METHODS: This investigation included 4002 cleaved embryos from 7535 oocytes retrieved in 688 patients undergoing IVF cycles in a multicentre trial. Embryos were evaluated locally at the inverted microscope at 28, 44 and 68 h (+/-1 h) post-insemination. Digital images of the embryos were assessed centrally by three blinded embryologists. To assess reproducibility, 215 randomly selected cleaved embryos from 33 patients were re-evaluated by the three central embryologists. RESULTS: The interobserver agreement among the central embryologists (using the same method of evaluation; 2D images) was good for classification of top-quality embryos (kappa 0.71-0.73), excellent for classification of normally developed embryos (kappa 0.83-0.86) and good-excellent for classification of transferable embryos (kappa 0.78-0.82). The interobserver agreement between local and consolidated central assessment (different methods of evaluation, inverted microscopy versus 2D images) was good for all three embryo classifications (kappa 0.64-0.79). The intraobserver reproducibility for all three overall embryo classifications was excellent for the consolidated central assessment (kappa 0.80-0.91). CONCLUSION: Embryo quality can be determined with a good degree of interobserver agreement independently of the method of evaluation. Embryologists classify embryos with excellent intraobserver reproducibility.

Embryo Implantation↗

PubMed1999

Development of serum-free culture systems for the ruminant embryo and subsequent assessment of embryo viability.

The mammalian embryo undergoes considerable changes in its physiology and energy metabolism as it proceeds from the zygote to the blastocyst stage. Complete development of the mammalian zygote in vitro was restricted to a few strains of mice and their F1 hybrids for many years, as the ruminant embryo arrested development at the 8- to 16-cell stage. The introduction of co-culture of ruminant embryos with somatic cells in the mid-1980s helped to alleviate this in vitro induced arrest. However, such culture systems required the use of complex tissue culture media and serum. Serum has subsequently been shown to induce several abnormalities during embryo development in culture and has been associated with the production of offspring with significantly greater birth weights than normal, leading to both difficulties in pregnancy management and an unacceptable frequency of neonatal death. Resurgence of interest in mammalian embryo physiology has culminated in the formulation of defined embryo culture media, capable of supporting a high percentage of viable blastocyst development in vitro. Optimum embryo development in culture has been shown to take place not in one, but two or more media, each designed to cater for the changing requirements and metabolism of the embryo as it develops. The development of viability assays to identify those embryos with the highest developmental potential will further increase the efficiency of embryo transfer procedures. Assays based upon nutrient uptake and subsequent utilization make promising candidates.

Animals↗

PubMed1991

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

OBJECTIVE: To assess embryo viability after ultrarapid freezing-thawing. DESIGN: We studied the fluorescence pattern of 35 ultrarapidly frozen-thawed multipronucleate human embryos exposed to fluorescein diacetate. SETTING: 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. PATIENTS, PARTICIPANTS: None. INTERVENTIONS: None. MAIN OUTCOME MEASURE: The fluorescence pattern was evaluated at room temperature after a 1-minute incubation in fluorescein diacetate solution, 4 hours and 24 hours after thawing. RESULTS: 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. CONCLUSIONS: Our experiments indicate an intact cell membrane permeability and an integrity of the intracytoplasmatic esterase enzyme activity of human embryos ultrarapidly frozen.

Blastocyst↗