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At least 487 records · Page 27Linked to original sources
PubMed1989

Inhibition of chick embryo hepatic uroporphyrinogen decarboxylase by components of xenobiotic-treated chick embryo hepatocytes in culture.

Uroporphyrinogen decarboxylase (UROG-D) activity in the 10,000g supernatant of 17-day-old chick embryo liver homogenates was determined by measuring the conversion of pentacarboxylporphyrinogen I to coproporphyrinogen I. The optimum pH of the enzyme was found to be approximately 6.0 and enzyme activity was found to be linear with protein concentrations ranging from 0.3 to 2.0 mg/mL. At a protein concentration of 1.2 mg/mL and pH 6.0, the activity was found to be linear for a reaction time of 50 min and to be approximately 10 pmol/(mg protein.min). This enzyme assay was used to demonstrate that a UROG-D inhibitor, previously reported to accumulate in rodent liver, also accumulates in 3,3'4,4'-tretrachlorobiphenyl (TCBP) and sodium phenobarbital (PB) treated chick embryo hepatocytes in culture. This results accords with the previous demonstration of a TCBP- and PB-induced decrease in UROG-D activity in this system. Uroporphyrin accumulation in chick embryo hepatocyte culture is interpreted as resulting from a combination of two mechanisms, viz., inhibition of UROG-D activity and uroporphyrinogen oxidation to uroporphyrin catalyzed by a cytochrome P-450 isozyme.

Animals↗
PubMed1992

In vitro evaluation of plasticizer activity on the growth and metabolism of chick embryo fibroblasts and on the development of chick embryo lungs.

Administration of di(2-ethylhexyl) phthalate (DEHP) to primary cultures of chick embryo fibroblasts brought about a decrease in cell proliferation rate after 48 h and an inhibition of both DNA and protein synthesis measured by [3H]thymidine and [3H]leucine, respectively, after 48 h. The growth of chick embryo lung rudiments in vitro was also depressed by DEHP treatment. Lung rudiment were smaller in DEHP-treated embryos after 6 days' treatment. These results indicate that DEHP has a cytostatic effect on embryonic cells and tissues.

Animals↗
PubMed2004

Vitamin a requirement for early cardiovascular morphogenesis specification in the vertebrate embryo: insights from the avian embryo.

Vitamin A is required throughout the life cycle, including crucial stages of embryonic and fetal development. With the identification of retinoic acid-specific nuclear transcription factors, the retinoid receptors, considerable advances have been made in understanding the molecular function of vitamin A. The requirement for vitamin A during early embryogenesis has successfully been examined in the vitamin A-deficient avian embryo during neurulation, when in the vertebrates crucial developmental decisions take place. These studies revealed that retinoic acid is essential during these early stages of embryogenesis for the initiation of organogenesis (i.e., formation of the heart). If retinoic acid is not present at this time, abnormal development ensues, leading to early embryonic death. Though the initial insult of the absence of vitamin A appears to be on the specification of cardiovascular tissues, subsequently all development is adversely affected and the embryo dies. Molecular and functional studies revealed that retinoic acid regulates the expression of the cardiogenic transcription factor GATA-4 and several heart asymmetry genes, which explains why the heart position is random in vitamin A-deficient quail embryos. During the crucial retinoic acid-requiring developmental window, retinoic acid transduces its signals to genes for heart morphogenesis via the receptors RARalpha2, RARgamma, and RXRalpha. Elucidation of the function of vitamin A during early embryonic development may lead to a better understanding of the cardiovascular birth defects prevalent in the Western world.

Animals↗
PubMed1992

Ovarian follicular characteristics, embryo recovery, and embryo viability in heifers fed high-fat diets and treated with follicle-stimulating hormone.

Postpubertal beef heifers (n = 55) were used to examine the effects of high-fat diets, independently of energy intake, on nonesterified fatty acid and lipoprotein metabolic patterns, ovarian follicular dynamics, and embryo recovery/viability after FSH superstimulation. High-lipid (HL) diets (5.4% added fat) increased (P < .01) serum concentrations of cholesterol, but not of nonesterified fatty acids, during the 35-d period before FSH treatment. Development of medium-sized (5 to 9.9 mm) follicles was enhanced (P < .05) during this period in heifers fed the HL diet. The HL diet increased total cholesterol (P < .05) and progesterone (P = .14) concentrations in follicular fluid obtained at ovariectomy (n = 10) 60 h after the onset of FSH treatment, but neither estradiol-17 beta nor androstenedione was affected. Granulosa cells recovered from FSH-induced, estrogen-active follicles in heifers fed the HL diet produced greater quantities of progesterone (P = .06) and less estradiol-17 beta (P < .05) in vitro than did granulosa cells from heifers fed the normal lipid diet. Dietary treatment did not influence FSH-stimulated recruitment of medium and large follicles, number of ovulations, embryo recovery, or embryo viability. Data suggest that increments in dietary fat intake can alter specific aspects of ovarian steroidogenic potential and can increase the population of medium-sized follicles theoretically available for maturation and harvest during the estrous cycle. However, conditions that limited the latter process in the current experiment are not understood and require further investigation.

Animals↗
PubMed1986

Activities in chick embryos of 7-ethoxycoumarin O-deethylase and aryl hydrocarbon (benzo[a]pyrene) hydroxylase and their induction by 3,3',4,4'-tetrachlorobiphenyl in early embryos.

Basal activities of 7-ethoxycoumarin O-deethylase and aryl hydrocarbon (benzo[a]pyrene) hydroxylase were determined in whole-liver homogenates from chick embryos of different ages, from newly hatched chicks and from chicks a few days old. The enzyme activities increased substantially in chick embryo livers between days five and 10, remained at a fairly constant level until day 19, and reached a peak in activity one day after hatching. The optimal pH value was lower than 7.0 for both enzyme activities. The total increase in activity from day five to one day after hatching was about 300-fold for 7-ethoxycoumarin O-deethylase and about 75-fold for aryl hydrocarbon (benzo[a]pyrene) hydroxylase. Treatment of eggs with 3,3',4,4'-tetrachlorobiphenyl resulted in increased metabolism of both substrates by five-day-old chick embryo livers. The increase in aryl hydrocarbon (benzo[a]pyrene) hydroxylase activity was 14-fold while that of 7-ethoxycoumarin O-deethylase was approximately double.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1984

Effect of varying levels of dietary vitamin D3 on turkey hen egg production, fertility and hatchability, embryo mortality and incidence of embryo beak malformations.

Two hundred Large White turkey hens were fed diets varying in vitamin D3 supplementation (300, 900, or 2700 IU/kg feed) from day-old to 37 weeks of age. Hens receiving 300 IU vitamin D3/kg feed produced fewer eggs, which were lighter in weight and had thinner shells than those laid by hens receiving the higher levels of vitamin D3. Fertility was not affected by treatment; however, hatchability of eggs from hens fed 300 IU vitamin D3/kg feed was reduced by 48% from that of hens fed the two higher levels. A shortened upper mandible, which was detected in embryos during Week 4 of incubation, accounted for approximately 10% of the total embryo mortality and 49.5% of the embryo mortality, during Week 4. It appeared that hens fed the low vitamin D3 did not have adequate amounts of the vitamin to transport to the egg for normal embryonic development.

Animal Feed↗
PubMed1999

Comparison of pronuclear stage embryo transfer and in vitro fertilization-embryo transfer following intracytoplasmic sperm injection.

To determine whether the mode of embryo transfer (PROST vs IVF) affected the outcome in intracytoplasmic sperm injection (ICSI) cycles, 237 ICSI cycles (106 PROST and 131 IVF) were analyzed. Several parameters, including patient age, duration of infertility, amounts of hMG used, number of mature eggs retrieved and injected, fertilization rate, number of embryos transferred, and clinical pregnancy rate, were compared. Most of the variable factors were not significantly different, except the mean numbers of transferred embryos which were significantly higher in the PROST group. The clinical pregnancy rate showed no statistical difference between PROST and IVF cycles (25.5 and 16.8%; p = 0.139). This study suggests that even the pregnancy rate in PROST cycles was slightly higher than IVF cycles, but there was no statistically significant difference between the two groups.

Adult↗
PubMed1976

[Plasma membrane proteins of embryo cells of various sea urchin species and hybrid embryo].

Differences are observed in plasma membrane proteins of S. intermedius and S. droebachiensis sea urchin embryo cells isolated at middle blastula stage by means of acrylamide-gel electrophoresis in presence of SDS, urea or non-ionic detergents--Triton X-100 or Brij 35. Electrophoretic mobilities of plasma membrane proteins of sea urchin hybrid embryo malemale S. intermedius X femalefemale S. droebachiensis were identical with electrophoretic mobilities of plasma membrane proteins of maternal species S. droebachiensis. Three sea urchin embryo species under study had just the same biosynthesis of plasma membrane proteins at middle blastula stage detected by 14C-aminoacids pulse-labeling followed by membrane isolation, electrophoresis and gel-autoradiography.

Animals↗
PubMed1975

The effects of experimental unilateral anotia on skull development in the chick embryo. II. Essentials of the development of the chondrocranium in normal embryos of 7-20 days of incubation.

In order to be able to describe adequately the developmental anomalies of the chondrocranium in unilateral anotia in the chick embryo, it seemed necessary to describe the essentials of the normal chondrocranial development. The following observations proved to be different from the available descriptions: 1. the occipital processes do not fuse with the ear capsules; 2. the tectum synoticum fuses only with the ear capsules; the occipital processes fuse later with the tectum synoticum by outgrowth to dorsal; 3. in the chick embryo there is no evidence for the existence of a tectum posterius; 4. the metotic fissure is in the cartilaginous stage of development not closed, but shifts laterally; 5. there is strong evidence that the pro-otic processes arise as independent structures which later fuse with the ear capsules. The results of the study of the development of the chondrocranium in the embryos in which experimentally unilateral anotia is produced, will be described in a following paper.

Animals↗
PubMed2005

Frozen embryo transfer outcome according to reason for freezing the embryos.

PURPOSE: To determine if cryopreservation influences pregnancy outcome following transfer. METHODS: Retrospective cohort analyses of frozen embryo transfer (ET) cycles divided into five different categories according to reason for freezing. RESULTS: Frozen embryos remaining as a result of failing to conceive with the previous fresh transfer or those remaining because of cancellation of fresh ET related to inadequate endometrial thickness, result in lower pregnancy rates (PRs). CONCLUSIONS: The fact that embryos never deselected in a group whose fresh ET was canceled because of risk of ovarian hyperstimulation did not have the best results suggests that these oocytes may not be of equal quality to those attained with a more modest response.

Abortion, Spontaneous↗
PubMed1969

The chick embryo neutralization test in the assay of meningococcal antibody. 1. Infection of the embryo with Neisseria meningitidis.

Present methods of controlling meningococcal cerebrospinal meningitis have failed to contain the disease. This has led to the search for effective vaccines and to the development of methods for assaying the potency of these vaccines, as well as for measuring the immune response of the individual. The feasibility of using the sero-protection test in embryonated eggs for the assay of meningococcal antibody has been investigated. The paper describes detailed investigations of the infectious process established by injecting Neisseria meningitidis by various challenge routes. Embryos, even 10-12 days old, showed high susceptibility to meningococci injected via the yolksac or chorioallantoic vein, and lesser susceptibility when injected via the intra-allantoic and chorioallantoic routes. The deaths of intravenously inoculated embryos coincided with the multiplication of the organisms and ensuing septicaemia. A study of the infection in embryos which had died, or were killed, 18-24 hours after inoculation showed a specific localization of the organisms in the brain.

Animals↗
PubMed1978

Measurement of metabolites in single preimplantation embryos; a new means to study metabolic control in early embryos.

Methods are described for preparing and analyzing single preimplantation mouse embryos for a variety of metabolites and cofactors (glucose-6-P, fructose-6-P, fructose-1,6-bisphosphate, ATP, AMP, Pi, citrate, isocitrate, alpha-ketoglutarate, and malate). Oil-well and enzymatic cycling techniques are combined to provide the sensitivity needed to measure the amounts present (10(-12) to 1o(-15) moles). After experimental treatment, embryos are collected on glass slides and freeze-dried. They can then be stored indefinitely under vacuum at -25 degrees C without deterioration. With these procedures, the embryos were collected at successive stages of development and subjected to starvation and refeeding with glucose, pyruvate or both. The results confirm the existence of a block at early stages at the P-fructokinase step. This may be due to inhibition by the very high citrate levels present. The data suggest that glycolysis is turned on late in preimplantation development by the rise in fructose-6-P, a deinhibitor of P-fructokinase. In the citrate cycle, no step between citrate and alpha-ketoglutarate is rate-limiting, but a step between alpha-ketaglutarate and malate appears to impede the flux at early embryonic stages.

Adenosine Monophosphate↗
PubMed1980

Hemorrhagic syndrome induced in chicken embryos by intravenous inoculation of ground chicken embryo extract.

The hemorrhagic syndrome which occurred after the IV inoculation of ground embryo extract into living chicken embryos resulted from rapid activation and depletion of the clotting mechanism. The syndrome was prevented by the addition of heparin to the ground embryo inoculum. The characteristics of the hemorrhagic syndrome suggest that the phenomenon is the result of disseminated intravascular coagulation.

Animals↗
PubMed1981

Influence of temperature of incubation on chicken embryo tracheal organ cultures and chick embryos infected with strains of avian infectious bronchitis virus.

The ciliostatic and embryo lethal effect of four strains of avian infectious bronchitis virus (IBV) were observed at two different incubation temperatures. In organ cultures, nephrosis-producing IBV strains (GN-2 and M-41) were slightly more ciliostatic and respiratory strains (Beaudette and Kita-1/Tokushima) less ciliostatic at 40.5 degrees C than at 37 degrees C. Mortality of chicken embryos infected with the GN-2, M-41 and Kita-1/Tokushima strains was greater at 40.5 degrees C than at 37 degrees C, while the reverse was true of the Beaudette strain which caused no embryo mortality at 40.5 degrees C. The Beaudette strain of IBV was the only one which could not be recovered from the kidneys of young chickens four days after infection. These results indicate that the different IBV strains may show variation in virulence at different temperatures in ovo and in organ cultures and this may be a reflection of the virulence and tropism for chickens.

Animals↗
PubMed1989

Octaploid mouse embryos produced by electrofusion polarize and cavitate at the same time as normal embryos.

We created enlarged octaploid mouse blastomeres by subjecting four-cell embryos to a large (greater than 2,000 V/cm) dc field of brief duration (10 microseconds). This electrofusion pulse caused three to four of the blastomeres to fuse in 60% of the embryos tested. Modifications of fusion chamber and medium enabled fusion of up to 20 embryos per pulse, greatly increasing the yield for this fusion method. The effectiveness of the electrofusion pulse depended upon such parameters as embryonic cell cycle time and the pH and temperature of the electrofusion medium. There was no discernable lag in the onset of the third cleavage division or the time of cavitation in fused blastomeres. These fused blastomeres also underwent polarization of their apical surfaces at the same time as controls in spite of their increased cell size. These results suggest that octaploid mouse blastomeres created via electrofusion divide normally through the blastocyst stage and polarize at the same time and in the same sequence as smaller control blastomeres. This suggests that the mechanisms underlying cell division, cavitation, and cortical polarization are not affected by changes in cellular size or ploidy.

Animals↗
PubMed1993

Spinal cord-notochord relationship in normal human embryos and in a human embryo with double spinal cord.

Spinal cord-notochord relationship was analyzed histologically and immunohistochemically in normal human conceptuses between the 4-8 developmental weeks and in a 8-week embryo with double spinal cord. In the early 4-week embryo, the gradual closure of the neural tube along the cranio-caudal body axis was paralleled by the differentiation of the median hindge point cells at the ventral midline of the tube and by its temporary close association with the notochord. During the 5th-8th developmental weeks, the neuroepithelium differentiating into three distinct layers was accompanied by a solid, ventromedially positioned notochord. In the abnormal 8-week embryo, the additional spinal cord was located ventrolaterally from the vertebral column. Both spinal cords appeared bilaterally asymmetric, with their floor and roof plates irregularly formed. An abnormally enhanced pattern of neuroepithelial differentiation characterized their dorsal parts. Furthermore, additional spinal nerves and ganglia and an abnormal bony structure were associated with the spinal cord positioned outside the vertebral column. The underlying vertebral bodies were misshaped and contained scattered supernumerary groups of notochord cells. Our investigation underlines the importance of the notochord-neural tube relationship in the morphogenesis of the spinal cord. We suggest that the double spinal cord was induced by the split notochord.

Cell Differentiation↗
PubMed1982

A biological embryo-reduction mechanism for the elimination of excess embryos in mares.

Only one embryo was found in each of 15 pregnant mares in which multiple, synchronous (0 or 1 day apart) ovulations were induced with a pituitary extract. In the brood-farm mares, fewer (P<.05) twin pregnancies were associated with synchronous, double ovulations (0 39 ), than with asynchronous, double ovulations (9 57 ). Higher (P<.05) pregnancy rates (number of mares pregnant, regardless of number of embryos) were obtained in pituitary extract-treated mares with multiple, synchronous ovulations (15 18 ) than in treated mares with single ovulations (6 14 ). Similarily, pregnancy rates were higher (P<.01) in brood-farm mares with double, synchronous ovulations (39 47 ) than in brood-farm mares with single ovulations (1320 2426 ). Our interpretation is that ova produced by synchronous, double ovulations are viable and fertilizable (indicated by higher pregnancy rates), but that one of the resulting embryos is eliminated (indicated by the absence of twins).

Journal Article↗