Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Embryos”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed1993

Multiple attempts at embryo transfer: effect on pregnancy outcome in an in vitro fertilization and embryo transfer program.

PURPOSE: This study derives from the observation that a correlation exists between failed first attempts (FFA) at embryo transfer caused by one or more embryos remaining in the catheter and reduced pregnancy rates (20.3 vs 3.0%). The aim of this study was to examine the relationship between failed first attempts at transfer and contamination of the transfer set; the related aspects of cervix dilatation and late embryo transfer were also investigated. RESULTS: The following observations were made. Retention of embryos in the transfer sets significantly reduced the pregnancy rate (P = 0.015); catheters contaminated with blood and cervical mucus indirectly contributed to this effect by increasing the incidence of failed first transfer attempts. Even though cervical dilatations, if indicated by uterus sounding, were done 2 days before embryo transfer, no pregnancies were effected in these 18 cases (P = 0.0001). Late transfers of embryos, due to delayed fertilization or slow cleavage rates, yielded a pregnancy rate of 10.5%. CONCLUSION: The approach of immediately retransferring retained embryos does not solve the problem of reduced pregnancy rates in FFA cases. It is suggested that ET should be repeated 1 day later in FFA cases in an attempt to improve pregnancy rates.

Blood↗
PubMed1976

Lysyl hydroxylase. Further purification and characterization of the enzyme from chick embryos and chick embryo cartilage.

A purification of up to 4000-fold is reported for lysyl hydroxylase (EC 1.14.11.4) from extract of chick-embryo homogenate and one of about 300-fold from extract of chick-embryo cartilage. Multiple forms of the enzyme were observed during purification from whole chick embryos. In gel filtration the elution positions of the two main forms corresponded to average molecular weights of about 580000 and 220000. These two forms could also be clearly separated in hydroxyapatite chromatography. In addition, some enzyme activity was always eluted between the two main peaks both in gel filtration and in hydroxyapatite chromatography. The presence of the two main forms was also observed when purifying enzyme from chick embryo cartilage. Both forms of the enzyme hydroxylated lysine in arginine-rich histone, which does not contain any -X-Lys-Gly- sequence. No difference was found between the enzyme from whole chick embryos and from chick embryo cartilage in this respect. Lysyl hydroxylase was found to have affinity for concanavalin A, indicating the presence of some carbohydrate residues in the enzyme molecule. Lysyl and prolyl hydroxylase activities increased when the chick embryo homogenate was assayed in the presence of lysolecithin. Preincubation of the homogenate either with lysolecithin or with Triton X-100 increased lysyl hydroxylase activity in homogenate, and in the 1500 x g and 150000 x g supernatants, suggesting that the increase in the enzyme activity was due to liberation of the enzyme from the membranes. Divalent cations were found to inhibit the activity of lysyl and prolyl hydroxylases in vitro. An inhibition of about 50% was achieved with 15 mM calcium 60 muM copper and 3 muM zinc concentrations. The mode of inhibition was tested with Cu2+, and was found to be competitive with Fe2+.

Albumins↗
PubMed1993

Developmental toxicity of methanol in whole embryo culture: a comparative study with mouse and rat embryos.

Methanol (MeOH), a widely used industrial solvent, has been proposed as an alternative motor vehicle fuel. Inhaled MeOH is developmentally toxic in both rats and mice but the mouse is more sensitive than is the rat. The contribution of the embryo to this differential sensitivity was studied in whole embryo culture (WEC) using equivalent stage rat (day 9) and mouse (day 8) embryos (plug day = day 0). Rat embryos were explanted and cultured in 0, 2, 4, 8, 12 or 16 mg MeOH/ml rat serum for 24 h and then transferred to rat serum alone for 24 h. Embryonic development of the 2 and 4 mg MeOH/ml groups was not significantly different from the controls whereas the higher concentrations resulted in a concentration related decrease in somite number, head length and developmental score. The 12 mg/ml dose resulted in some embryolethality as well as dysmorphogenesis, while the highest dose was embryolethal. MeOH was dysmorphogenic in vitro in rat embryos at a MeOH concentration comparable to that reported in maternal serum following teratogenic in vivo exposures. Day 8 mouse embryos were explanted and cultured in 0, 2, 4, 6 or 8 mg MeOH/ml culture medium (75% rat serum, 25% Tyrode's salt solution) for 24 h. Embryonic development in the 2 mg/ml MeOH group was not significantly different from the controls but all higher concentration groups had a significant decrease in developmental score and crown-rump length. The high concentration group also suffered 80% embryolethality. Thus, mouse embryos were affected at MeOH concentrations which were not dysmorphogenic or embryotoxic in the rat, suggesting that the higher sensitivity of the mouse to the developmental toxicity of inhaled methanol is due, at least in part, to greater intrinsic embryonal sensitivity of this species to methanol.

Animals↗
PubMed2006

In vitro embryo production and embryo transfer in domestic and non-domestic cats.

Over a 5-year interval, multiple laparoscopic oocyte retrievals were done in fishing cats (Prionailurus viverrinus), caracals (Caracal caracal) and domestic cats after ovarian stimulation with gonadotropins. From 21 retrievals in five fishing cats, 579 preovulatory oocytes (mean = 27.6) were recovered and 348 embryos were produced in vitro (mean = 16.6). A total of 452 preovulatory oocytes (mean = 25.1) were recovered from 18 of 24 retrievals in six caracals and 297 (mean = 16.6) embryos were produced. An additional 16 caracal embryos (19%) were produced after in vitro maturation of 83 oocytes, 59 of which came from six retrievals producing only immature oocytes. The presence of corpora lutea at oocyte retrieval occurred in each species (1) at a similar frequency (33%) and (2) more frequently during January through May (11 of 15 retrievals) than during the latter half of the year (4 of 30 retrievals). Of the 12 embryo transfer procedures done in fishing cats, one pregnancy (8%) was obtained and one live kitten born after the auto-transfer of 10 Day-6 embryos. In caracals, a total of 46 Day-4 or Day-5 embryos were auto-transferred to six recipients, one of which delivered two live kittens. Then, 109 caracal embryos were cryopreserved before thawing and transferring to nine recipients (mean = 12.1) on Days 5 or 6. From three pregnancies established (33%), a total of three kittens were born. Two to six gonadotropin treatments/oocyte retrievals were done in domestic cats during 1999 through 2003; an average of 24.9, 23.5, 22.0, 23.1, 23.5 and 40.9 oocytes (P > 0.05) were recovered at the first through the sixth treatment cycles from 138, 138, 97, 49, 22, and seven retrievals, respectively.

Animals↗
PubMed1999

Human endometrial stromal cells improve embryo quality by enhancing the expression of insulin-like growth factors and their receptors in cocultured human preimplantation embryos.

OBJECTIVE: To demonstrate the mechanism by which human endometrial stromal cells improve embryo quality in coculture. DESIGN: Randomized study. SETTING: Academic research center. PATIENT(S): Patients undergoing IVF-ET. INTERVENTION(S): Donated human embryos were cultured randomly either alone (group A) or with human endometrial stromal cells (group B), and the embryonic expression of insulin-like growth factors (IGFs) and their receptors was detected by reverse transcriptase polymerase chain reaction after culture. MAIN OUTCOME MEASURE(S): The embryo frequency distribution of groups A and B before and after culture and the embryonic transcripts of the IGF family genes of the two study groups after culture were compared. RESULT(S): The embryo frequency distribution of the day 3 embryonic stages in groups A and B was not different. However, after culture, a statistically significant difference in blastocyst formation was observed between groups A and B. A significant increase in the expression of IGF-1, IGF-2, the IGF-1 receptor, and the insulin-receptor also was noted. Among the embryos that reached the blastocyst stage, the expression of IGF-1 and the IGF-1 receptor also was significantly different in the two study groups. CONCLUSION(S): Human endometrial stromal cells enhanced the expression of IGFs and their receptors in cocultured human embryos, which may be essential for improving embryo quality.

Blastocyst↗
PubMed2005

Embryos produced in vitro from bulls carrying 16;20 and 1;29 Robertsonian translocations: detection of translocations in embryos by fluorescence in situ hybridization.

Robertsonian translocation rob(16;20) in the heterozygous state was discovered in a subfertile bull of the Czech Siemmental breed. A chromosomal analysis of its family has shown that this dicentric fusion is formed de novo. The present experiments were designed to detect rob(16;20) and determine its incidence for in vitro produced embryos, using fluorescence in situ hybridization (FISH) and rob(1;29) as a detection control. To characterize semen of both bulls with the rob translocations, their sperm was examined for DNA integrity by the sperm chromatin structure assay (SCSA). For in vitro fertilization of oocytes, spermatozoa from a rob(16;20) bull carrier (Czech Siemmental breed) and those from a rob(1;29) bull carrier (Charolais breed) were used. Embryos at the 6- to 8-cell stage were cultured in a vinblastine-supplemented medium for 17 h, and embryos at the blastocyst stage were cultured in a colcemide-supplemented medium for 4 h. The embryos were fixed in methanol and acetic acid with Tween-20. Painting probes for chromosomes 16 (Spectrum Green) and 20 (Spectrum Orange) and chromosomes 1 (Spectrum Orange) and 29 (Spectrum Green) were simultaneously hybridized. In the embryos derived from the rob(16;20) bull, the presence of this translocation was not detected. On the other hand, 52.5% of the embryos derived from the rob(1;29) bull were translocation carriers. There was no significant difference in the frequency of this translocation between early and advanced embryos.

Animals↗
PubMed2001

Cryopreservation of embryos, blastocysts, and pregnancy rates of blastocysts derived from frozen-thawed embryos and frozen-thawed blastocysts.

PURPOSE: To evaluate the development of cryopreserved embryos when thawed and subsequently cultured to the blastocyst stage in comparison to transferring cryopreserved blastocysts. METHODS: In this retrospective clinical study, we have evaluated 170 cycles in patients undergoing IVF treatment for infertility. Cryopreserved embryos were thawed and were subsequently cultured and transferred at the blastocyst stage. Cryopreserved blastocysts (Day 6) were thawed and transferred immediately. RESULTS: Five hundred and sixty embryos and 444 blastocysts have been thawed. In the embryos group, the survival rate was 89% while in the blastocyst group the survival rate was 56%. In the embryos group the blastocyst development rate was 24.5%. The implantation rate in the embryos group was 20.6% per group blastocyst transferred compared to 5.3% in the blastocyst group. CONCLUSIONS: The ability of cryopreserved embryos to develop to blastocysts and their implantation potential does not seem to be greatly affected by the cryopreservation procedure.

Blastocyst↗
PubMed2006

Embryo development and embryo transfer in the European mink (Mustela lutreola), an endangered mustelid species.

The European mink is an endangered Mustelidae species and thus requires effective conservation measures, although little is known about reproduction in this species. In particular, preimplantation development has not been studied and, therefore, embryonic development and the growth of embryos was documented in the present study for European mink using light and fluorescent microscopy. Embryos develop in the oviducts and then migrate into the uterus on Day 6 post coitum (p.c.) at the morula stage. Embryos expanded as blastocysts from Day 7 until implantation on Day 12 p.c. Based on these findings, the use of embryo transfer for a conservation programme for the European mink was evaluated. Embryos were flushed from European mink resource females and transferred into the uterine horns of recipient hybrid females (honoriks and nohoriks). These hybrids were obtained by mating European polecat males with European mink females and vice versa. A total of 40 embryos was transferred and 20 live kits were born. The rates of pre- and postnatal survival were 50% and 70%, respectively. Both male and female offspring were lighter at birth in the embryo transfer group compared with naturally born controls, but there was no difference at 3 months of age.

Animals↗
PubMedDate not supplied

Relationships between the developmental potential of human in-vitro fertilization embryos and features describing the embryo, oocyte and follicle.

This paper investigates the relationship of features of in-vitro fertilization (IVF) embryos and the associated oocyte and follicle to the outcome of transfer. It differs from previous studies in including a range of features (n = 53) and in using class probability tree analysis. This is a non-parametric multivariate method which expresses relationships as simple rules of features characterizing the 'take home baby' and 'no take home baby' (negative pregnancy test) classes of embryo batches. Data were analysed retrospectively. Fifty-three (embryo, oocyte and follicular) features for each of the three embryos in the transferred batch were collected for 200 IVF patients. Each batch of three embryos was described by a representative value for each feature. The relationship between features and outcome of transfer was analysed. Only four of the 53 features were identified as predictive. However, an appropriate combination of these four (embryo grade, cell number, follicle size and follicular fluid volume) achieved satisfactory predictivities while offering a simplified and more quantitative basis than regularly used criteria. The key component of the composite embryo grading allotted by embryologists turned out to be cell number. The existing predictive use of follicular size was corroborated and an independent additional predictive contribution of follicular fluid volume was found. The study also suggests that the 49 remaining features have little additional predictive value.

Embryo Transfer↗
PubMed1999

Embryo depth during the first trimester. Data required for embryo dosimetry.

RATIONALE AND OBJECTIVES: To provide data regarding embryo depth during the extremely radiosensitive gestational stages of organogenesis and early fetal period for use in embryo dosimetry. METHODS: Ultrasound examination was performed in 73 pregnant women at gestational age 5 to 13 weeks and in a control group of 75 nonpregnant women. Embryo skull and abdominal depth from the maternal skin surface were determined in the anteroposterior direction. Uterus depth was measured in the control group. Measurements were taken before and after voiding. Gestational age and maternal age, height, and weight were noted. Body mass index (BMI) was estimated for every woman from the formula BMI = W/H2. RESULTS: The mean embryo pre- and postvoid skull depth was 8.3 and 5.7 cm and the mean abdominal depth was 8.4 and 5.8 cm, respectively. The mean pre- and postvoid uterus depth was 9.5 and 4.7 cm. Mean abdominal depth and mean skull depth values were significantly different than mean uterus depth for full as well as for empty bladder. Embryo skull depth and abdominal depth were found to be significantly correlated with maternal BMI. Skull and abdominal dimensions were found to be significantly correlated with gestational age. CONCLUSIONS: During the first trimester, embryo depth ranges from 4 to 10 cm, depending on the individual, the status of the bladder, and the maternal BMI. For an accurate determination of embryo depth, ultrasound measurement should be performed.

Abdomen↗
PubMed1982

Development of the articular cavity in paralyzed chick embryos and in chick embryo limb buds cultured on chorioallantoic membranes.

The development of digital joints of chick embryo paralyzed with dacamethonium bromide and of joints in chick embryo limb buds cultured on chorioallantoic membranes was studied. The digital joints of 45 paralyzed and 40 control embryos and the joints of 37 grafts and 30 control legs were examined histologically. Six preselected grafts were studied by electron microscope. Our results demonstrate that paralysis does not completely inhibit the early stages of joint clefting. In many paralysis does not completely inhibit the early stages of joint clefting. In many paralyzed embryos, small clefts appeared in the periphery and occasionally in the central part of the interzone. Unlike in normal embryos, they rapidly disappeared, inducing fusions across the joints. Early, 2-day paralysis during a period of normal clefting inhibited irreversibly the development of the articular cavity that failed to appear after a cessation of the drug. Paralysis initiated in older embryos caused rapid regression and partial fibrous ankylosis of previously fully differentiated joints. Grafts from 4- to 6-day-old embryos usually failed to develop a full range of skeletal segments. Normal development of skeletal segments occurred in grafts from older donors. The articular cavity failed to develop in almost all grafts. Early cavitation accompanied by characteristic cell changes was found in a few joints. These cellular changes are suggestive of an intrinsic mechanism of early cavitation, but joint motion is required for the full differentiation and maintenance of the joint cavity.

Allantois↗
PubMed2005

Transition of the pregnancy rate of bisected bovine embryos after co-transfer with trophoblastic vesicles prepared from in vivo-cultured in vitro-fertilized embryos.

Bisected bovine embryos were co-transferred with trophoblastic vesicles (TVs). These TVs were prepared by dissection of conceptuses that were collected by uterine flushing after culture for seven days in the uterus following transfer of embryos derived by in vitro fertilization (IVF). Pregnancy diagnoses were performed twice, between Day 26 and Day 43 and between Day 38 and Day 73 post-estrus by ultrasonography. The pregnancy rate was significantly increased at first pregnancy diagnosis when demi-embryos were transferred with TVs (66.7%, 16/24) compared with the control group (34.5%, 10/29) (P < 0.05). Three losses occurred in the co-transfer group between the first and second pregnancy diagnosis. The final pregnancy rates according to delivered offspring were 41.7% (10/24) and 27.6% (8/29), respectively. There were no statistically significant differences between the pregnant and non-pregnant groups with regard to the average diameter of the TVs measured before transfer at three points during the gestation period. The birth weight and gestation lengths of the offspring were almost the same for the co-transfer and control groups. In the co-transfer group, the genetic identities of calves from the separated embryos were not affected by the TVs, as confirmed by parental blood type testing. Delivered offspring in co-transferred groups showed normal morphology. In conclusion, the present study indicates that co-transfer of TVs prepared from conceptuses cultured in vivo following transfer of IVF embryos enhances the fertility of demi-embryos during the early stages of pregnancy, as has similarly been shown in previous research for those prepared from in vivo embryos.

Animals↗
PubMed1988

Sexing of half-embryos produced by microsurgical bisection of mouse morulae and production of chimeric mouse of defined sex composition by aggregating two sexed half-embryos.

Using the halved morulae of mice obtained with microsurgical technique, the following two experiments were performed. 1) Sexing of half-embryos by chromosomal analysis and transfer of the half-embryos after determining the sex of the other monozygotic half. One half of the bisected embryo was cultured in Colcemid solution (0.04 micrograms/ml) to be ensured for chromosomal preparation. More than 50% (152/270) of the blastulated embryos from the halves could be sexed by direct sex chromosome analysis. Thirty-nine of the half-embryos of which the co-twin halves were sexed, were transplanted in to the uterine horns of 18 pseudopregnant mice, and twelve became pregnant. The autopsies of them on Day 18 to 20 of pregnancy, revealed the presence of 16 fetuses. The morphological sex of these fetuses thus obtained coincided completely with the previous judgement based on the chromosomal sexing. 2) Production of chimeras of defined sex composition by aggregating two half-morulae of defined sex. Out of 147 pairs of half-morulae of two different strains (ICR and C3H/He), which were replaced in pairs into empty zona pellucidae, 107 (72.8%) were aggregated successfully and developed in vitro into full expanding blastocysts of typical form. Among the 107 aggregate blastocysts, 31 were sexed for both component embryos by chromosomal analysis on the co-twin half-embryos. When these 31 blastocysts were transferred, 11 living offspring including 4 chimeras were obtained. Transfer of 12 male-male and 5 female-female aggregate blastocysts resulted in 8 males and 1 female, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

[Analyses of the factors affecting the occurrence of polypronuclear embryos in in-vitro fertilization and embryo transfer].

OBJECTIVE: To investigate the factors affecting the occurrences of the polypronuclear embryos in in-vitro fertilization and embryo transfer (IVF-ET). METHODS: The data from 145 IVF-ET cycles and 1,168 oocytes were analyzed by logistic regression for multiple factors. The influences of the couple's age, the superovulation stimulation protocols, the number of the follicles punctured and the oocytes obtained, the preinseminational interval, the quality and quantity of seminal and inseminational sperms, and the oocyte fertilization ratio on the incidences of the polypronuclear embryos from the matured, and immature oocytes were examined respectively. RESULTS: The incidence of the polypronuclear embryos from matured oocytes was significantly negatively correlated with the women age and the number of the follicles punctured, and the incidence from immature oocytes was significantly positively correlated with the density of sperms at grade a and b and the oocyte fertilization ratio. CONCLUSIONS: The woman's age and the number of follicles are the main factors which influence the occurrence of polypronuclear embryos from matured oocytes, while the density of the seminal sperm with high motility and the fertilization ratio play important roles in the occurrence of polypronuclear embryos in immature oocytes. Stimulating greater number of follicles might be benefit for the reduction of occurrence of polypronuclear embryos.

Embryo Transfer↗
PubMed1992

Studies on teratological testing using chicken embryos--effects of solvents, injection sites and the age of the embryo.

The purpose of this study was to examine the effects of solvents, injection sites and embryo age when using chicken embryos for teratological testing. The results obtained were as follows: 1) Solvents: distilled water, physiological saline, sesame oil, 25% ethanol, 0.5% carboxymethylcellulose and 0.1% methylcellulose solution were not toxic in Day-4 embryos (eggs incubated for 4 days). 2) With 6-aminonicotinamide, air space injection more effectively induced malformations in chicken embryos. With boric acid, however, yolk sac injection was better. It was shown therefore that the appropriate injection site varied according to the test drug. 3) 6-aminonicotinamide induced characteristic malformations when injected into embryos of various ages ranging from 4 to 13 days of incubation. On the other hand, boric acid was teratogenetic only when injected into Day-3 or Day-4 embryos. It seems, therefore, that the age of the embryo at the time of administration is of critical importance and that the optimum time of administration varies according to the test drug.

6-Aminonicotinamide↗
PubMedDate not supplied

Rate of blastocyst development from excess embryos remaining in culture after day 3 embryo transfer.

OBJECTIVE: To assess the rate of blastocyst development (BDR) from embryos remaining in culture after day-3 embryo transfer (ET), and its relationship to cause of infertility. STUDY DESIGN: Retrospective cohort study in tertiary-care IVF Center. Blastocyst development rate (BDR) after day-3 ET was assessed in 126 women who underwent either conventional IVF or ICSI. RESULTS: Mean age, early follicular FSH levels, number of 2PN zygotes, number of excess embryos, and number of ET were similar between patients that underwent IVF and ICSI. Overall, 20% of extra embryos from conventional IVF patients developed into blastocysts compared to 14% of embryos obtained from ICSI. Cause of infertility did not affect BDR, even in patients who required ICSI due to male factors. CONCLUSIONS: Low rates of blastocyst development from excess embryos are similar between IVF and ICSI patients. Only 15 to 25% of excess embryos left in culture develop into blastocysts, regardless of cause of infertility. Physicians and patients can use this information to adjust both AR treatment protocols and patient expectations.

Adult↗
PubMed1988

Evaluation of media, protein supplements and potassium concentration for human in vitro fertilization and embryo transfer by preimplanted mouse embryo development.

A two-cell mouse embryo was used to investigate the effect of three different media and protein supplements together with different potassium (K+) concentrations on embryo development. The embryos of the ICR mouse showed higher expanded blastocyst rates in Biggers-Whitten- Whittingham (BWW) than in Ham's F10 (F10) and Whittingham's T6 (T6). The embryos of the C57BL X CBA strain showed the highest hatching rate in BWW but the expanded blastocyst rate was highest in F10. Embryos from both strains developed more rapidly with BSA supplement with no difference between human serum (HS) and fetal cord serum (FCS). Relatively higher K+ concentrations (7.7 mM and 17.8 mM) suppressed 2-cell mouse embryo development. F10 and BWW were used for human in vitro fertilization and embryo transfer (IVF-ET). The fertilization rate was significantly higher in BWW than in F10. Two viable pregnancies were obtained in BWW cycles. This study supports the use of BWW over other standard media for human IVF-ET.

Animals↗
PubMed1993

A modified two-step method for cryopreservation of mouse embryos for purposes of embryo banking.

So far, more than 17,000 embryos have been frozen in the repository of the cryobank in the Institute of Molecular Genetics. The freezing of embryos from more than 20 inbred, congenic and mutant strains has been completed. For purposes of embryo banking, a modified two-step method was used. The first step includes slow freezing, after seeding, to -25 degrees C, rate 0.3 degrees C/min, and is followed by a second step involving direct transfer of the embryos into liquid nitrogen. A relatively high percentage of survival is found (85-95%) after thawing, depending on the strain used. If thawed embryos are cultivated briefly and transferred into recipients, 20-35% living offspring are obtained. Mice born after embryo transfer are subjected to genetic control in order to check the correct procedure of embryo banking.

Animals↗