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At least 541 records · Page 30Linked to original sources
PubMed1987

Morphometric study of cartilage dynamics in the chick embryo tibia. II. Dexamethasone-treated embryos.

The cartilage dynamics in the tibia of dexamethasone-treated chick embryos has been studied by means of morphometric methods. Treated embryos showed a delay in the longitudinal growth of the tibia, as well as in the growth of all structures enclosed by the perichondrium-periosteum. The cartilage formation rate remained nearly unchanged (above 1 mm3/day) from Day 12 to Day 14, whereas the cartilage resorption rate was zero up to Day 13, and showed a non-significant increase from Day 13 onwards. This might be related to the scarcity of resorptive cells found in the cartilage-marrow interface. By Day 14 a certain recovery of the growth rhythm was observed. These results indicate that the greatest effect of dexamethasone occurs at the level of cartilage resorption.

Animals↗
PubMed1986

Quantification of the transition from oocyte-coded to embryo-coded glucose phosphate isomerase in mouse embryos.

A quantitative electrophoretic analysis of glucose phosphate isomerase (GPI-1) allozymes produced by heterozygous Gpi-1sa/Gpi-1sb mouse embryos has enabled us to estimate separately the contributions of GPI-1 enzyme that were oocyte coded, encoded by the embryonic, maternally derived Gpi-1sa allele and encoded by the embryonic, paternally derived Gpi-1sb allele. The oocyte-coded GPI-1 activity is stable until 2 1/2 days and then declines and is exhausted by 5 1/2 to 6 1/2 days post coitum (p.c.). The maternally and paternally derived Gpi-1s alleles are probably usually activated synchronously but several possible exceptions were observed. This activation was first detected in 2 1/2-day embryos. Total GPI-1 activity falls to a minimum around 3 1/2 to 4 1/2 days, even though embryonic gene expression has already begun. The profile of oocyte-coded GPI-1 activity is consistent with the suggestion (Harper & Monk, 1983) that there is a mechanism for the removal of oocyte-coded gene products at around 2 1/2 days p.c. The method of analysis described is applicable to other dimeric enzymes with electrophoretic variants.

Animals↗
PubMed1979

The effects of experimental unilateral anotia on skull development in the chick embryo. V. The development of the brain and its meningeal envelope in embryos of 9-20 days of incubation.

In a total number of 27 normal and 27 unilaterally anotic chick embryos, varying in age from 9-19 days, the morphogenetic relationships between the neurocranium on the one hand and the brain and its meningeal envelope on the other were studied. The results showed that, in general, unilateral anotia slightly interferes with the development of the bain. Only the homolateral nucleus tangentialis and cerebellar auricle proved to be underdeveloped. However, the brain of the anotic embryos progressively develops asymmetrically: In an antero-posterior and a ventro-dorsal direction abnormal flexures are present, and various components of the brain on the anotic side undergo changes in shape and position. These changes in brain morphology are interpreted as secondary features. Hence, the conclusion is drawn that the neurocranium, through the intermediary of the meningeal envelope, controls--or at least is capable to control--the general morphological development of the brain.

Animals↗
PubMed1983

Transfection of brown Leghorn embryo fibroblasts (BLEF) and duck embryo fibroblasts (DEF) by means of DNA isolated from RSV-transformed cells.

Transfection of Brown Leghorn embryo fibroblasts (BLEF) and embryo fibroblasts (DEF) was made by means of DNA isolated from RSV-transformed cells. DNA samples were carried out by means of phenol method, according to Svoboda at al. [16, 20] from the tumor sarcoma tissue and from cells transformed in vitro (XC and PR-RSH). DNA samples isolated from cell cultures were used for transfection BLEF and DEF cell cultures. Positive transfection results after the use DNA samples were recorded in BLEF and DEF1 cell cultures. The efficiency of transfection of BLEF is about 30% and for DEF1 10%.

Animals↗
PubMed1983

The transition from oocyte-coded to embryo-coded glucose phosphate isomerase in the early mouse embryo.

The proportions of glucose phosphate isomerase (GPI-1) allozymes produced by early (Gpi-1sa/Gpi-1sb female X Gpi-1sc/Gpi-1sc male)F1 mouse embryos were analysed by quantitative cellulose acetate electrophoresis. Technical controls showed that this system is extremely sensitive, quantitatively reproducible and quite accurate. Genetic controls established that the Gpi-1sa/Gpi-1sb mothers were homozygous for the Gpi-1tb temporal allele, that produces relatively high GPI-1 activity in the oocyte. The oocyte-coded enzyme lasted until about 5 1/2 days post coitum (p.c.) or shortly thereafter. The maternally derived, embryonic Gpi-1s allele was expressed no earlier than the paternally derived allele. This was first expressed between 2 1/2 and 3 1/2 days p.c. In this cross, most of the transition from oocyte-coded to embryo-coded GPI-1 occurred between 2 1/2 and 5 1/2 days p.c.

Alleles↗
PubMed1995

Embryo experimentation and the murder prohibition: a casuistic examination of the utilitarian and pro-life positions on the moral status of the embryo.

Argument concerning the permissibility of embryo experimentation has tended to proceed from the opposed ethical principles of utilitarianism and the sanctity of human life, neither of which entirely reflects Western society's present position on murder and moral obligations. Singer's utilitarian arguments propose a test of subject attributes for admission to the protection of morality, and it is argued that this approach is entirely at odds with our current axiomatic application of the murder prohibition of post-birth humans. Similarly, those arguing from a pro-life position do not take account of the ambivalence of our application of this principle to the pre-birth human, as seen in abortion. In the attempt to deal with the quandary of the moral position of the embryo, we should, following the philosophical precedent of casuistry, start from the position of our current moral certainties, rather than expose ourselves to the social dangers of an untried rationality divorced from practice.

Australia↗
PubMed1996

[New immortalized cell lines from transgenic rat embryos. I. The isolation and characteristics of cell lines from rat embryos with an injected v-mos oncogene coupled with or without the gene for genecitin resistance].

A collection of established cell lines was made by means of their explanation into 15 day old transgenic rat embryos. Some of these cell lines were characterized by measuring the cultivated population redoubling time, the saturation density and oncogenicity. A cytogenetic analysis was also carried out. The phenotypical analysis and studies of reproduction permit to define these lines as transformed immortalized non-oncogenic lines capable of contact inhibition. Cytogenetic studies were performed only on Mos N3, N6 and Mos+Neo N1, N6 lines. The karyotypes of cells in Mos lines were normal, and the karyotypes of cells in Mos+Neo lines had chromosomal markers (2 and 3, resp.). These markers result from arrangements of chromosomes 6, 9, 14, 15 and 17. the "thru deletions" of region q1 2qter (line N1) and region q22qter (line N6) of chromosome 15 were revealed in Mos+Neo lines by the summarized reconstruction karyotype method. We propose that these deletions of chromosome 15 and other chromosomes rearrangements may play an important role in transformation of cells from transgenic embryos in vitro, because RB1 antioncogene was mapped on rat chromosome 15.

Animals↗
PubMed2005

Embryo technologies and animal health - consequences for the animal following ovum pick-up, in vitro embryo production and somatic cell nuclear transfer.

Mammalian reproductive technologies that aim either to complement or to transcend conventional livestock breeding options have contributed to some of the most remarkable achievements in the field of reproductive biology in recent decades. In so doing they have extended our horizons in two distinct dimensions, the first concerning what it is technically possible to achieve and the second relating to the time-frame within which an individual's life-long developmental capability is initially established and ultimately realized or undermined. Our impressions of the benefits and values, or otherwise, of technologies such as in vitro embryo production and nuclear transfer are rightly influenced by the extent to which they impinge on the health of animals either subjected to or derived from them. Here, we consider some of the health implications of oocyte/embryo-centric technologies applied to farm livestock.

Animal Welfare↗
PubMed1982

Neuroblast of the grasshopper embryo as a new mutagen test system. II. Chromosome breakage induced by in vitro exposure of embryos to the direct-acting mutagens 4NQO, MNNG, adriamycin, and bleomycin.

The dose-response for the induction of acentric chromosome fragments was determined in neuroblasts of the grasshopper embryo (Chortophaga viridifasciata De Geer, Orthoptera: Acrididae) exposed in vitro to four direct-acting chemical known to be mutagenic, clastogenic, and carcinogenic: 4-nitroquinoline-1-oxide (4NQO), N-methyl-N-nitro-N-nitrosoguanidine (MNNG), Adriamycin (ADM), and bleomycin (BLM). After a 1-hr exposure followed by a 3-hr recovery period (untreated cell cycle time is 4 hr), acentric fragments were observed at doses down to 1 microM 4NQO, 1.25 microM MNNG, and 0.125 microM ADM and BLM. After an 8-hr continuous exposure, acentric fragments were induced by 4NQO at a dose as low as 0.125 microM. These low concentrations also reduced the number of dividing cells. No chromosome aberrations or mitotic effects were observed in untreated embryos or in those exposed only to the solvent dimethyl sulfoxide. Because of the short cell cycle and the sensitivity of the neuroblast to the induction of acentric chromosome fragments by chemical clastogens, a minimum of time is needed to perform the test. From a comparison with the prominent clastogen test systems currently used, it is concluded that the grasshopper neuroblast test is the fastest and that it detects some agents that some systems do not. Grasshoppers have a worldwide distribution. If neuroblasts of other species prove to be as sensitive to mutagens as those of Chortophaga, investigators in many countries would have available a eukaryotic mutagen test system that is simple, fast, reproducible, and inexpensive.

4-Nitroquinoline-1-oxide↗
PubMed1981

Hepatitis A virus in cell culture. III. Propagation of hepatitis A virus in human embryo kidney cells and human embryo fibroblast strains.

The propagation and adaptation of hepatitis A virus (HAV) in human embryo kidney cells (HKC) is shown. The growth curve of HAV in the first passage through HKC is compared to the growth curve in the tenth passage through HKC. It is shown that in the course of 18 passages through HKC, HAV adapted to these cells causing the virus to grow much more rapidly. The cell-bound HAV is compared to the HAV released in the cell-culture supernatant during the ninth passage through HKC. The HAV from the tenth passage through HKC is shown to be able to replicate also in a human embryo fibroblast strain (HFS). Furthermore, adaptation of the HAV to HFS is demonstrated.

Adaptation, Physiological↗
PubMed1991

Recommended protocols based on a survey of current practice in genotoxicity testing laboratories: III. Cell transformation in C3H/10T1/2 mouse embryo cell, BALB/c 3T3 mouse fibroblast and Syrian hamster embryo cell cultures.

A standardized protocol and guidelines for the performance of cell transformation testing in mouse embryo (C3H/10T1/2), mouse fibroblast (BALB/c 3T3) and Syrian hamster embryo (SHE) cells have been developed. The protocol is based primarily on current laboratory practices as determined by responses to a detailed questionnaire completed by North American and European governmental, university and contract laboratories involved with cell transformation experimentation. This report identifies those modifications to previously described methodologies which are being used on a regular basis and also serves to clarify confusing or inconsistent practices.

Animals↗
PubMed1982

Monoclonal antibody to murine embryos defines a stage-specific embryonic antigen expressed on mouse embryos and human teratocarcinoma cells.

A murine stage-specific embryonic antigen (SSEA3) is defined by reactivity with a monoclonal antibody prepared by immunization of a rat with 4- to 8-cell-stage mouse embryos. This antigenic determinant, present on oocytes, becomes restricted first to the inner cell mass at the blastocyst stage, and later to the primitive endoderm. Murine teratocarcinoma stem cells do not react with this antibody, whereas human teratocarcinoma stem cells are SSEA3-positive. This antigenic determinant is not expressed on a variety of other human and murine cell lines, but is found on the surface of human erythrocytes. It is a carbohydrate and is present on both cell-surface glycolipids and glycopeptides. These results demonstrate the feasibility of identifying stage-specific antigenic determinants with monoclonal antibody prepared against embryos. The need for thorough screening on a variety of cell types to establish developmentally important cross-reactivities is also emphasized.

Animals↗
PubMed1986

Embryo transfer as a means of controlling the transmission of viral infections. VIII. Failure to detect foot-and-mouth disease viral infectivity associated with embryos collected from infected donor cattle.

Foot-and-mouth disease (FMD) viral infectivity detectable in cell cultures or by animal inoculation was not found to be associated with any of 48 washed zona pellucida-intact (ZPI) embryos collected from 8 cattle during the acute stages of disease. Similarly, infectivity was not found to be associated with any of 42 washed ZPI embryos collected from 3 cattle 21 d after infection with FMD.

Journal Article↗
PubMed1995

Screening of some variables influencing the results of embryo transfer in the ewe. I. Five-day-old embryos.

Rasa Aragonesa ewes (n = 89) received 2 embryos on Day 6 of the estrous cycle (Day 0 = estrus) from 46 donors of the same breed that had been superovulated with FSH-p. The influence of several variables on fertility and prolificacy after transfer was studied by discriminant analysis. Our results showed that the main variables that contributed to a high fertility rate were the degree of synchrony (better outcome if donors come into estrus later than the recipients); Fluorogestone acetate (FGA) to estrus interval and interval from previous lambing in the recipients, ovulation rate of the donors and recipients (better if superior to the mean); prolificacy of recipients in the previous lambing; and difference in developmental stage of the pair of transferred embryos (better if inferior to the mean). The main variables affecting prolificacy were the ovulation rate and weight of the donors and progesterone concentrations of the recipients (better if lower than the mean); age of the donors and difference in progesterone concentrations between donors minus those of the recipients (better if higher than the mean). The percentage of ewes correctly classified into lambing or not lambing status was 73% (P < 0.001) and that of the ewes correctly classified as lambing 1 or 2 lambs was 81.8% (P < 0.001). Whether or not the criteria we have established for optimum transfer results are applicable to conditions other than our own still needs to be confirmed.

Journal Article↗
PubMed2001

Changes in embryo production results and ovarian recrudescence during the acclimatisation to the semiarid tropics of embryo donor Holstein-Friesian cows raised in a temperate climate.

Pregnant Holstein-Friesian (HF) heifers were transported from central Europe (defined as temperate conditions) to north-eastern Brazil (defined as tropical, semiarid conditions). They were kept in open-sided pens with a hard floor, a roof for shade and sprinkled with water for 10 min every hour if ambient temperature exceeded 30 degrees C. Their diet was balanced to meet nutritional requirements and they were fed twice daily. Control animals were randomly chosen first and second lactation animals located on a farm 25 km away and receiving similar management. Imported animals were superovulated in 1996 (n=63) and 1997 (n=96), compared to 38 and 45 cows in the control herd. The variates recorded were: the interval post-partum to first oestrus; changes in ovarian size and activity; responses to superovulation; and, embryo quality. The average daily milk yields of the imported cows were 20.0 and 23.3 l in 1996 and 1997, respectively compared to 22.1 l throughout the experiment for cows in the control herd. The post-partum anoestrus interval in the imported cows were 112.1+/-30.5 days in 1996 compared to 55.0+/-18.0, 48.2+/-12.0 and 42.6+/-10.7 days in 1997 for control cows. The size and functionality of the ovaries was lowest for the imported animals in 1996 but did not differ between other group-year combinations. These animals also had a lower superovulatory response in 1996 than control cows in terms of the number of ovulations (6.4+/-4.3 versus 13.6+/-5.9, P<0.05) and good quality embryos (1.2+/-0.9 versus 4.4+/-2.1, P<0.05). The two groups of cows did not differ in respect of these characters in the second year of the study. The imported cows had lower reproductive efficiency and responses to superovulation in their first year in their new environment. A period of approximately 1.5 years is required for full adaptation.

Adaptation, Physiological↗
PubMed1998

Role of integrins in mouse eyelid development: studies in normal embryos and embryos in which there is a failure of eyelid fusion.

Eyelid fusion normally occurs between E15.5 and E16.5 of mouse embryonic development and results from the migration of a population of periderm-derived epithelial cells over the corneal surface. Cell migration is known to depend on extracellular matrix receptors of the integrin family and to be regulated by growth factors. We were therefore interested that a failure of eyelid fusion has been reported in mice that are homozygous null for the transforming growth factor alpha (TGF-alpha) gene and in mice (invalpha5beta1) in which a transgenic alpha5beta1 integrin under the control of the involucrin promoter is misexpressed in differentiating keratinocytes. We examined expression of the alpha2beta1, alpha3beta1, alpha5beta1 and alpha6beta4 integrins during eyelid fusion in wild-type embryos and found selective upregulation of the alpha5beta1 integrin and its ligand, fibronectin, in the migrating eyelid tip cells. In TGF-alpha null embryos, the failure of eyelid fusion was correlated with a failure to upregulate the alpha5beta1 integrin and fibronectin in the tip cells. Using beta-galactosidase as a reporter gene in transgenic mice, we observed specific activity of the involucrin promoter in the eyelid tip cells. In invalpha5beta1 mice the transgenic human integrin was overexpressed not only in the tip cells but throughout the eyelid epidermis. In contrast, the endogenous, murine, alpha5beta1 integrin was only weakly expressed in the tip cells. We speculate that selective and coordinated expression of the alpha5beta1 integrin and fibronectin in eyelid tip cells is required for eyelid fusion and may be under the control of growth factors that include TGF-alpha.

Animals↗
PubMed1998

Expression and subcellular distribution of rel/NF kappa B transcription factors in the preimplantation mouse embryo: novel kappa B binding activities in the blastocyst stage embryo.

We describe the expression patterns and subcellular localisation of murine rel/NF kappa B transcription factors and their inhibitors during preimplantation development in the mouse. We find that the known rel and I kappa B proteins are ubiquitously expressed during early murine embryogenesis. The differential persistence of individual rel and I kappa B transcripts in the first cleavage stage embryo and analysis of the 3'UTR suggests that rel and I kappa B protein expression may be regulated at the level of mRNA stability and translation. At the stages of early mouse embryogenesis examined, there was no evidence for strong induction of rel dimer translocation into the nucleus. However, novel kappa B-binding proteins are found in the mouse blastocyst and may provide an alternative mechanism for regulation of gene expression via the kappa B motif in the early mouse embryo.

3' Untranslated Regions↗
PubMed2004

Heterotopic Caesarean scar pregnancy combined with intrauterine pregnancy successfully treated with embryo aspiration for selective embryo reduction: case report.

Ectopic pregnancy situated in a Caesarean section scar is a rare but potentially life-threatening event. Because of its rarity, there are no universal treatment guidelines to manage this condition. We report a case of IVF-induced triplet heterotopic pregnancy of early gestational age that included one Caesarean scar pregnancy diagnosed as early as 6 weeks gestation. Treatment with embryo aspiration under vaginal ultrasonography for selective embryo reduction was given and the concurrent intrauterine twin pregnancy was preserved successfully.

Adult↗