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 1,693 records · Page 94Linked to original sources
PubMed1993

Role of platelet-derived growth factor in development of in vitro matured and in vitro fertilized bovine embryos.

This experiment was designed to determine whether the stimulatory effects of bovine oviductal epithelial cells (BOEC) on development of early bovine embryos are due to platelet-derived growth factor (PDGF). Four hundred and twenty five 8-cell bovine embryos derived from in vitro maturation and in vitro fertilization procedures were equally and randomly allotted to one of the following culture treatment groups: control medium alone (Menezo's B2 medium; MB2), MB2 with 1 ng PDGF ml-1 (PDGF), 1 ng PDGF ml-1 and 10 micrograms anti-PDGF antibody ml-1 (PDGF + Ab), BOEC or BOEC and 10 micrograms anti-PDGF antibody ml-1 (BOEC + Ab). All embryos were cultured in 100 microliters of serum-free MB2 medium supplemented with 2 mg fatty-acid-free bovine serum albumin ml-1. Embryos for all treatment groups were incubated at 39 degrees C and 5% CO2 in humidified air in groups of five embryos per well in 96-well culture plates until 7 days after in vitro insemination. A higher proportion of embryos developed to > 8-cell and to the morula stage following culture with PDGF, BOEC or BOEC+Ab than with MB2 alone. Incubation of PDGF and BOEC-treated embryos with anti-PDGF reduced development to the morula and blastocyst stages. However, anti-PDGF did not completely inhibit blastocyst development when added to BOEC. In addition, embryos incubated with BOEC and anti-PDGF contained a reduced number of inner cell mass cells compared with embryos incubated with BOEC alone. These results indicate that PDGF provides a developmental stimulus similar to BOEC for bovine embryos at the fourth cell cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Oxygen uptake and carbohydrate metabolism by in vitro derived bovine embryos.

The consumption of oxygen, uptake of pyruvate and glucose and production of lactate were determined for groups of bovine embryos produced in vitro from the one-cell to the blastocyst stage (day 0-6 of culture). Measurements were made in Hepes-buffered synthetic oviduct fluid medium supplemented with 1.0 mmol pyruvate l-1, 10 mmol D,L-lactate l-1 and 1.5 mmol glucose l-1 and also 3 mg BSA ml-1 and, from day 5 of development, 10% (v/v) fetal calf serum. The amount of ATP production was determined from oxygen consumption and the proportion of glucose taken up that could be accounted for by lactate production. The data revealed that oxygen consumption was relatively constant from days 0-4 of culture (0.24-0.27 nl per embryo h-1), but increased with the initiation of compaction (0.39 nl per embryo h-1) and continued to increase with the formation and expansion of the blastocoel (0.9 nl per embryo h-1). Both pyruvate and glucose uptake followed similar patterns. Furthermore, when plotted against oxygen consumption, both pyruvate and glucose uptake increased significantly (P < 0.001) in a linear relationship (R2 = 0.61 and 0.49, respectively). Lactate production also increased with development and accounted for 40% of glucose uptake at day 0 of culture (putative zygotes), increasing to 70% by day 2 (eight-cell stage) and 100% of glucose uptake from day 4 of culture onwards. ATP production followed a similar pattern to that of oxygen consumption (60-85 pmol per embryo h-1 from day 0 to day 4) increasing with compaction (124 pmol per embryo h-1) and blastulation (221 pmol per embryo h-1). For precompaction stages, 93-96% of ATP production was derived from oxidative phosphorylation, decreasing to 82% with compaction. ATP produced by oxidative phosphorylation could be accounted for by the uptake of pyruvate, suggesting that bovine embryos produced in vitro utilize little endogenous substrates when appropriate exogenous substrates are present in the culture medium. The data revealed that bovine embryos were dependent on oxidative phosphorylation for energy (ATP) production at all stages of pre-elongation development, with perhaps a shift in dependence towards glycolysis in conjunction with compaction. It follows that oxidizable substrates, such as pyruvate and certain amino acids, are preferred in embryo culture medium during development in vitro.

Adenosine Triphosphate↗
PubMed1997

Effect of different concentrations of potassium on pig embryos developing in vitro.

The effects of varying the potassium concentration in Whitten's medium on the development of pig embryos in vitro was investigated. Osmolality was maintained by adjusting the NaCl concentration. In Expt I, 209 one-cell to early blastocyst stage embryos were individually cultured in 50 microliters microdrops of glucose-free Whitten's medium containing 0.4% (w/v) BSA and 1.5, 3.0, 6.0 or 12.0 mmol potassium l-1. The percentages of embryos undergoing blastocoel formation and expansion for each cell stage evaluated did not differ (P > 0.10) among the various concentrations of potassium. However, more four-cell embryos commenced hatching in 3.0 mmol potassium l-1 (53%) than in 1.5 mmol potassium l-1 (16%) (P < 0.05) and 12.0 mmol potassium l-1 (24%) (P < 0.10). The time required for embryos to develop blastocoels, expand and initiate hatching was not affected (P > 0.10) by the concentration of potassium in the medium. However, blastocoel formation by one- to two-cell embryos was delayed (P < 0.05) in medium with 1.5 mmol potassium l-1. In Expt 2, 89 four-cell embryos were cultured in medium containing 6.0 or 24.0 mmol potassium l-1. No differences (P > 0.10) were observed in the percentages of embryos undergoing blastocoel formation, expansion and hatching or in the time required to develop to these stages. The number of cells in embryos recovered at 96 h was greater (P < 0.05) in medium containing 6.0 compared with 24.0 mmol potassium l-1 (32.9 +/- 1.7 versus 26.9 +/- 2.1, respectively). These results demonstrate that pig embryos are tolerant to a wide range of potassium concentrations when the osmolality of the medium is maintained by adjusting the NaCl concentration. These results also suggest that limitations in development due to culture conditions are not due to inappropriate concentrations of this ion.

Animals↗
PubMed1999

Nonsurgical collection and nonsurgical transfer of preimplantation embryos in the domestic rabbit (Oryctolagus cuniculus) and domestic ferret (Mustela putorius furo).

The objective of this study was to develop nonsurgical methods of embryo collection and transfer in domestic rabbits (Oryctolagus cuniculus) and domestic ferrets (Mustela putorius furo) to serve as models for use in mammals in which surgical procedures are the usual means for applying embryo transfer technology. Specially designed transcervical catheters were used together with a fibre optic endoscope to visualize and then catheterize the rabbit and ferret cervices. Five consecutive transcervical uterine flushes in each of eight superovulated female rabbits 78-89 h after an ovulatory injection of LH resulted in the retrieval of 187 embryos, for an average of 23 embryos per rabbit. A total of 116 embryos were nonsurgically transferred to the uteri of ten recipients, and resulted in 23 young (20%). Eight rabbits (80%) produced young with an average litter size of 2.88 (range 1-7). Ten consecutive transcervical uterine flushes in each of 37 female ferrets 145-178 h after an ovulatory injection of hCG resulted in the retrieval of 324 embryos, an average of 8.76 embryos per ferret. A total of 251 embryos from 27 donors were nonsurgically transferred to the uteri of 31 recipients, and resulted in 65 young (26%). Twenty-eight of the recipients (90%) were initially pregnant, as indicated by postpartum necropsies, and twenty-two ferrets (71%) produced young. The average litter size was 2.95 (range 1-7). This is the first report of live births resulting from the nonsurgical collection of embryos from a donor followed by nonsurgical transfer of those same embryos to a synchronous recipient. The methods reported here can serve as models for use in other mammals in which direct visualization and manipulation of the cervix are not possible, and will be particularly useful in endangered species.

Animals↗
PubMed2005

Effect of cryopreservation on the cellular integrity of equine embryos.

Horse embryos are rarely cryopreserved in practice because expanded blastocysts tolerate freezing poorly, and the embryo begins expanding very soon after entering the uterine cavity. This study examined the effects of freezing on cytoskeleton integrity, and investigated whether cell damage could be reduced using trypsin to thin the blastocyst capsule or cytochalasin-B (cyto-B) to stabilise the cytoskeleton. Sixty-nine embryos were recovered 7 days after ovulation and equilibrated in 10% glycerol, with or without pretreatment with 0.2% trypsin or 7.5 microg/ml cyto-B. Forty-two of the embryos were frozen; the rest were used to determine whether pre-freezing treatment alone caused cell damage. Subsequently, embryos were stained with 4',6-diamidino-2-phenylindole dihydrochloride, to identify dead cells, and fluorescently labelled phalloidin, to assess cytoskeleton quality. Without freezing, none of the treatments affected cell viability. And although Cyto-B altered actin distribution, the cytoskeleton returned to normal during a 4-h culture. Following cryopreservation, the percentage of dead cells (11.1 +/- 1.3%) did not differ between treatments (P > 0.05), but significantly fewer cells died in small (< or = 300 microm) than in large embryos when neither pretreatment was used (P > 0.05); the effect of embryo size was, however, not significant after pretreatment with trypsin or cyto-B, and trypsin improved the likelihood of an intact cytoskeleton post thaw. However, trypsin treatment also resulted in a 'sticky' capsule that complicated embryo handling, and cyto-B-induced actin-depolymerisation was not reversed during a 6-h post-thaw incubation. Thus, while trypsin pretreatment improved cytoskeleton preservation and both trypsin and cyto-B may reduce cell death during cryopreservation of large embryos, both treatments induced other changes likely to compromise embryo survival.

Animals↗
PubMed2005

Amino acid depletion and appearance during porcine preimplantation embryo development in vitro.

Preimplantation embryos can consume and produce amino acids in a manner dependent upon the stage of development that may be predictive of subsequent viability. In order to examine these relationships in the pig, patterns of net depletion and appearance of amino acids by in vitro produced porcine preimplantation embryos were examined. Cumulus oocyte complexes derived from slaughterhouse pre-pubertal pig ovaries were matured for 40 h in defined TCM-199 medium (containing PVA) before being fertilised (Day 0) with frozen-thawed semen in Tris-based medium. After 6 h, presumptive zygotes were denuded and cultured in groups of 20, in NCSU-23 medium modified to contain 0.1 mM glutamine plus a mixture of 19 amino acids (aa) at low concentrations (0.02-0.11 mM) (NCSU-23(aa)). Groups of 2-20 embryos were removed (dependent on stage) on Day 0 (1 cell), Day 1 (two- and four-cells), Day 4 (compact morulae) and Day 6 (blastocysts) and placed in 4 mul NCSU-23aa for 24 h. After incubation, the embryos were removed and the spent media was analysed by HPLC. The net rate of amino acid depletion or appearance varied according to amino acid (P < 0.001) and, apart from serine and histidine, stage of development (P < 0.014). Glycine, isoleucine, valine, phenylalanine, tryptophan, methionine, asparagine, lysine, glutamate and aspartate consistently appeared, whereas threonine, glutamine and arginine were consistently depleted. Five types of stage-dependent trends could be observed: Type I: amino acids having high rates of net appearance on Day 0 that reached a nadir on Day 1 or 4 but subsequently increased by Day 6 (glycine, glutamate); Type II: those that exhibited lower rates of net appearance on Days 0 and 6 compared with the intermediate Days 1 and 4 (isoleucine, valine, phenylalanine, methionine, arginine); Type III: amino acids which showed a continuous fall in net appearance (asparagine, aspartate); Type IV: those that exhibited a steady fall in net depletion from Day 0 to Day 6 (glutamine, threonine); Type V: those following no discernable trend. Analysis of further embryo types indicated that presumptive polyspermic embryos on Day 0 had increased (P < 0.05) net rates of leucine, isoleucine, valine and glutamate appearance, and reduced (P < 0.05) net rates of threonine and glutamine depletion compared with normally inseminated oocytes. These data suggest that the net rates of depletion and uptake of amino acids by pig embryos vary between a) amino acids, b) the day of embryo development and, c) the type of embryos present at a given stage of development. The results also suggested that the net depletion and appearance rates of amino acids by early pig embryos might be more similar to those of the human than those of the mouse and cow.

Amino Acids↗
PubMed2003

Evaluation of developmental competence of vitrified-warmed early cleavage stage embryos and their application for chimeric mouse production.

The developmental competence of in vitro cultured embryos vitrified-warmed at an early cleavage stage (2- or 4, 8-cell stage) was examined by both direct transfer into recipient animals and after in vitro manipulation for chimeric mice production using embryonic stem (ES) cells. Vitrified-warmed embryos transferred at the morulae and blastocyst stages showed fetus development comparable to control embryos, although blastocyst development of vitrified-warmed embryos was significantly slower than that of controls. When vitrified-warmed early cleavage stage embryos were used for chimeric mouse production using ES cells, 1 to 10% of the injected or aggregated embryos developed into chimeric neonates and germ-line chimeric mice were obtained from all ES cell lines. This study indicates that embryos developed in vitro from vitrified-warmed embryos have equivalent competence with unvitrified embryos irrespective of stage of vitrification and that these vitrified-warmed embryos maintain adequate viability even after in vitro manipulation such as aggregation and microinjection with ES cells.

Animals↗
PubMed1990

Relationship between plasminogen activator production and bovine embryo development in vitro.

The relationship of plasminogen activator (PA) production to cell stage, cell number and changes in overall diameter and zona pellucida thickness for bovine embryos developing in vitro was determined. Late morulae to blastocysts (n = 80) were collected nonsurgically from naturally mated, estrous-synchronized, superovulated crossbred beef cows. Embryos were cultured, one embryo per 25-microliters microdrop, for 6 d. At 24-h intervals, embryos were evaluated for stage of development and transferred to fresh microdrops; media were recovered for PA analysis. In addition, embryo diameter and zona pellucida thickness were measured with an ocular micrometer. Plasminogen activator production was determined using a caseinolytic assay with urokinase as the standard. Changes in diameter, zona pellucida thickness and PA production per 24-h interval for each embryo were plotted, and the graphs were cut out and weighed. Sixty-one embryos (76%) completed the hatching process. Total PA production was correlated positively (P less than .005) to embryonic size (r = .40), developmental stage (r = .35) and cell number (r = .35) and negatively, but weakly, correlated to zona pellucida thickness (r = -.13; P = .267). Hatched embryos produced more total PA than embryos that did not hatch (.140 +/- .011 vs .070 +/- .019 g; P less than .01). These results suggest that as embryonic size and cell number increase and development progresses, bovine embryos liberate more PA.

Animals↗
PubMed1995

Developmental changes in sensitivity of bovine embryos to heat shock and use of antioxidants as thermoprotectants.

Experiments were conducted with in vitro-produced bovine embryos to determine whether 1) increased culture temperatures (i.e., heat shock) adversely affected embryonic development, 2) embryos become more resistant to heat shock as they advance in development, and 3) selective antioxidant molecules alleviate heat shock effects on embryonic development. Development of 2-cell embryos to > or = 16-cell stage on d 5 after in vitro fertilization was not affected by a heat shock of 40 degrees C for 3 h, but 41 or 42 degrees C for 3 h decreased (P = .004) development. In a separate experiment, development of 2-cell embryos was decreased (P = .01) by exposure to 41 degrees C for 3 h but not for 1 h. In contrast, development of morulae to blastocysts was not affected by heat shock of 41 degrees C for 1 or 3 h. Medium supplementation with 50 nM glutathione or 50 mM taurine before heat shock did not reduce the effects of heat shock (41 degrees C for 3 h) on 2-cell embryos. Likewise, addition of glutathione ester, a more membrane-permeable analog of glutathione, did not protect 2-cell embryos from heat shock. In conclusion, early bovine embryos are susceptible to disruption in development caused by heat shock. As embryos progress in development, they acquire resistance to heat shock. Glutathione, taurine, and glutathione ester were not effective in alleviating the effects of heat shock on development of 2-cell embryos. Consequently, molecules have yet to be identified that can protect early-stage bovine embryos from the adverse effects of heat shock.

Animals↗
PubMed1982

Development of one-cell porcine embryos in two culture systems.

The effect of culture system and protein supplementation on the development of one-cell porcine embryos was investigated. One hundred and sixty-four one-cell embryos were collected at slaughter from 19 handmated gifts. Culture systems evaluated were microdrops of Whitten's medium (WM) under paraffin oil (M) or tubes with 4.0 ml of WM (T). Also tested was T with a 2.0 ml paraffin oil overlay (O). Media evaluated were WM with: no bovine serum albumin (-BSA), 15 mg/ml BSA (+BSA) or 10% (v/v) heat-treated porcine serum (+HTPS). Twenty-nine, 29, 28, 29, 28 and 21 one-cell embryos were assigned to treatments T + BSA + O, T - BSA, M + BSA, M - BSA and M + HTPS, respectively. All cultures were conducted at 37 C in a humidified atmosphere of 5% CO2 in air. At the cessation of division, embryos were fixed and stained, and each was assigned a cleavage index bases on the number of divisions completely in culture. The mean cleavate indexes for embryos cultured in T + BSA + O (2.07) and T + BSA (1.97) were not significantly different, but both were greater (P less than .05) than the indexes for T - BSA (1.09), M + BSA (1.12), M - BSA (.82) and M + HTPS (.86). Mean cleavage indexes for embryos cultured in T - BSA, M + BSA, M - BSA and M + HTPS were not significantly different. More (P less than .05) embryos developed to the blastocyst stage in T + BSA + O (6/29) than in either T - BSa (0.28) or M BSA (0.28). Fragmentation was greater (P less than .05) in embryos cultured in M - BSA than in embryos cultured in tubes. These results suggest that culture tubes of WM with 1.5% BSA are superior to microdrops and WM with 10% HTPS in supporting the in vitro development of one-cell porcine embryos.

Animals↗
PubMed1987

Nuclear transplantation in bovine embryos.

This study was conducted to develop a method for transplanting nuclei in bovine embryos and to test the development of several stages of donor nuclei transplanted to enucleated pronuclear recipient embryos. Pronuclear embryos were centrifuged to reveal nuclei. Nuclei were removed without penetrating the plasma membrane as membrane-bound karyoplasts, and were inserted into enucleated zygotes by electrically induced cell fusion. The highest rate of fusion (79%) occurred in Zimmerman Cell Fusion medium at 100 V for 20 to 40 microseconds with the fusion membranes oriented parallel to the electrodes. The effect of nuclear transplantation on development was tested in pronuclear embryos in which nuclei were removed and reinserted and the embryos were then transferred to sheep oviducts for 5 d. Of the intact nuclear transplant embryos recovered, 5/29 (17%) developed to morulae or blastocysts compared with 11/30 (37%) of the non-manipulated embryos. Two nuclear transplant embryos were transferred to a recipient cow, and both developed to normal offspring. When nuclei from two-, four-, or eight-cell embryos were transplanted to pronuclear recipient embryos, no development was observed.

Animals↗
PubMed1996

Experimentally induced Chiari-like malformation with myeloschisis in chick embryos.

Though several pathogenetic theories concerning the frequent association of Chiari malformation and hydrocephalus with myeloschisis have been suggested, none of them explains all the aspects of the disorder. To investigate whether myeloschisis is the direct cause of Chiari malformation and hydrocephalus or these conditions are the results of another basic event, we observed the morphological changes of the posterior cranial fossa and its components in the chick embryos with surgically induced myeloschisis. To make myeloschistic lesions, we opened the neural tube for a length of 9-11 somites in Hamburger and Hamilton stage 16-19 chick embryos. They were divided into cervicothoracic (C-T) and lumbosacral(L-S) groups according to the area of incision. The embryos were re-incubated until postoperative day 11. In the control group, embryos were incubated with the eggshell window open as their experimental counterparts. The survival rates of each group were as follows; 11% (9 survivors/85 operated embryos), 8% (7/83), and 17% (10/60) in the C-T, L-S and control groups, respectively. Myeloschisis positive rates were 100% in the operated groups and 0% in the control group. The heads of embryos were sectioned along the sagittal plane to observe the morphological changes in the posterior cranial fossa and its components. Of the survivors, five in the C-T group, two in the L-S group and six in the control group were available for light microscopic inspection. In the majority of embryos with myeloschisis, without difference between the C-T and L-S groups, the fourth ventricles were smaller than those of the control group and the subarachnoid spaces in the posterior cranial fossa were also narrower. In embryos with severe changes, the cerebellum displaced downward comparing with that of the control embryos. No evidence of hydrocephalus was present Though not always typical, morphological changes similar to Chiari malformation were observed in chick embryos with surgically induced myeloschisis. It suggests a strong direct causal relationship between the two conditions and supports the theories of derangements in cerebrospinal fluid dynamics rather than those of primary mesenchymal or neural origin as a pathogenetic mechanism of Chiari malformation.

Animals↗
PubMed1989

Use of ultramicrofluorometric methods for the study of single preimplantation embryos.

Ultramicrofluorescence and video fluorescence microscopy are highly sensitive techniques for studying embryo metabolism and developmental potential. These techniques are attractive in that they allow one to study single embryos and thus to detect more subtle changes in embryo metabolism or intracellular pH which, using less sensitive techniques or batches of embryos, would likely go undetected. This is especially important in those species where few embryos can be recovered from a single mother. An additional advantage of ultramicrofluorescence techniques lies in their lack of invasiveness to the embryo under study. When measuring nutrient uptake, several measurements can be made on a single embryo that can then be placed back into culture for evaluation of its developmental potential. Alternatively, test embryos can be transferred back into a recipient for determination of embryo viability. This flexibility further illustrates the beneficial aspects of using ultramicrofluorescence techniques for studying embryo metabolism and development.

Animals↗
PubMed1990

The role of plasma thyroid hormones in the regulation of body weight of single comb White Leghorn and broiler embryos.

Studies were conducted to determine if sex differences in embryo weights existed in a light-weight breed of chickens (the Single Comb White Leghorn, SCWL) and in a heavy broiler strain of chickens. Plasma thyroid hormone concentration was measured to determine its relationship to embryo weight. Male SCWL embryos were heavier than females at 15 and 17 days of incubation, but not at 13 days. Male broiler embryos were heavier than females at 13 and 15 days of incubation, but not at 17 days. There was no sex difference in the levels of plasma triiodothyronine (T3) or of tetraiodothyronine (T4) of SCWL embryos at those respective ages. The plasma T4 in male broiler embryos was significantly lower than that in the females at 15 and 17 days of incubation, but not at 13 days. There was no relationship between plasma T3, and the weight of SCWL embryos. There were significant linear regressions of embryo weight on the plasma T4 levels for SCWL males at 13 and 15 days of incubation and for SCWL females at 13 and 17 days of incubation, respectively. A significant regression of embryo weight on plasma T4 was found in female broiler embryos at 13 days of age, but not in females at other ages or in males at any of the ages studied.

Age Factors↗
PubMedDate not supplied

Histone H1 kinase activity in one-cell mouse embryos blocked in the G2 phase by X-irradiation.

The activation of the p34cdc2/cyclin B complex is responsible for driving the cell cycle from the G2- to the M-phase. To investigate the effects of irradiation on the activity of the p34cdc2/cyclin B complex in preimplantation embryos, we irradiated one-cell mouse embryos with 2.5 Gy of X-rays at the early pronuclear stage, and measured the fluctuations of histone H1 kinase activity (a biochemical indicator of the kinase activity of the p34cdc2) at different times during the radiation-induced G2-arrest. BALB/c embryos were chosen for these experiments, since earlier results obtained in our laboratory had shown that such a treatment induces a G2-arrest of about 20 hours in more than 90% of the embryos. Our data showed that histone H1 kinase activity of irradiated embryos remained at a very low level during the period of G2-arrest. The level of activity found during late division of the G2-arrested embryos was also significantly lower in comparison with that of control embryos or irradiated embryos dividing without delay. All together, our results suggest that a) low levels of histone H1 kinase activity are sufficient for the division of one-cell embryos, b) there could be a link between the levels of histone H1 kinase activity in mitosis and the health status of the embryo.

Animals↗
PubMed2001

Transfer of refrozen twice-thawed embryos do not decrease the implantation rate.

PURPOSE: To assess the ability of twice frozen/thawed multi-cell embryos to implant in the human uterus. METHOD: Fourteen frozen embryo transfer (ET) cycles, in which at least one twice-frozen embryo was thawed for transfer, were matched to frozen ET cycles in which no twice-frozen embryos were thawed. The number of embryos thawed at the pronuclear stage and at the multi-cell stage were matched. RESULTS: Multi-cell embryos frozen once had a 76.3% survival rate after thaw and those frozen twice had a 74.0% survival rate. For frozen ET cycles that had no twice-frozen embryos, the viable pregnancy and implantation rates were 58.3% and 29.8%, respectively. The corresponding rates for cycles involving at least one twice-frozen embryo were 50.0% and 25.5%, respectively. CONCLUSION: The inclusion of twice-frozen embryos in the embryo pool did not reduce the implantation rate.

Adult↗
PubMed2001

Successful production of offspring after superovulation and in vitro culture of embryos from domestic ferrets (Mustela putorius furos).

In an effort to expand the use of ferrets as models for genetic disease, several experimental parameters that are required for successful genetic manipulation in this species were investigated. Optimum superovulation (19.3 +/- 0.6 oocytes and embryos per female) was achieved after injections of 100 iu equine chorionic gonadotrophin (eCG) and 150 iu human chorionic gonadotrophin (hCG). The ovulation rate achieved by the treatment was more than double that induced by mating. Mating with a male immediately after hCG treatment did not significantly alter the number of oocytes ovulated or the number of embryos present, indicating that mating is not required for superovulation in ferrets. Of embryos harvested at the one-cell stage, 64.5% and 47.1% developed into blastocysts when cultured in vitro in CZB or TCM-199 plus 10% fetal bovine serum (FBS) media, respectively. In contrast, only 17.1% of embryos cultured in vitro in NCSU-23 developed to the blastocyst stage. Both freshly retrieved and in vitro cultured embryos from cinnamon-coloured parents produced live young when transferred at the eight-cell stage into albino, pseudo-pregnant recipients. The percentage of kits delivered relative to embryos transferred was 61% for freshly retrieved embryos and 32% for embryos cultured in vitro. These results demonstrate successful embryo transfer in ferrets and provide a basis for further study of genetic modelling approaches in this species after embryo manipulation.

Analysis of Variance↗
PubMedDate not supplied

The incidence of mitotic abnormalities in cryopreserved eight-cell early and compacted mouse embryos.

The effects of slow freezing-rapid thawing on viability and chromosomal complement of eight-cell early and eight-cell compacted mouse embryos were investigated. The abnormalities connected with damage to the mitotic apparatus, and with chromosome damage were investigated in cryopreserved embryos by cytological analysis. The embryos were preserved using 1M glycerol as cryoprotectant and a slow cooling regime to -30 degrees C before transfer to liquid nitrogen. The proportion of mitotic abnormalities in compacted embryos was significantly higher (13.1%) than in early embryos (5.9%) and unfrozen control embryos (3.9%) in these studies performed after thawing. This was reflected after cryopreservation by a reduced viability of the embryos as judged by culture to the hatching blastocyst stage--compacted 8-cell embryos (71.8+/-4.7%) versus controls (78.4+/-5.9%) and cryopreserved early-stage 8-cell embryos (86.1+/-4.0%)--p<0.05 in each case. However, aneuploidy rates were low in all groups in both fresh and cryopreserved embryos (around 3%).

Aneuploidy↗