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At least 667 records · Page 37Linked to original sources
PubMed1989

Glucocorticoid-induced cataract in chick embryo monitored by Raman spectroscopy.

Glucocorticoid-induced cataract lens in chick embryo was monitored by laser Raman spectroscopy. The lens opacity that appeared in chick embryo is a reversible one. Raman spectra show no significant change in the relative content of water or secondary structure of the proteins upon lens opacification. The intensity ratios of tyrosine doublet bands in Raman spectra between clear and opaque lens portions are changes. This change is reversible, and is interpreted as a protein-water phase separation that occurred during lens opacification.

Animals↗
PubMed1992

Isolation of factor Xa from chick embryo as the amniotic endoprotease responsible for paramyxovirus activation.

In chick embryo, certain paramyxoviruses mainly target the chorioallantois and the allantoamnion and show no extensive further spreading in the other organs. This has been explained by the possible presence of an endoprotease activating the viral fusion glycoprotein precursor in the allantoic and the amniotic fluid, and its absence in other places or organs. We previously isolated such an endoprotease from the allantoic fluid and demonstrated its identity with the clotting factor Xa. Exactly the same endoprotease by all the criteria including the N-terminal amino acid sequence was now isolated from the amniotic fluid. Thus, the factor Xa seems to be a major host determinant of the viral tropism in chick embryo.

Amino Acid Sequence↗
PubMed1997

Effects of N-nitrosodimethylamine on glutathione levels during development of chick-embryo.

Glutathione content in the liver, kidney and eye of chick embryo increased during development, having the maximum at day 17 after incubation of eggs. Activity of enzymes involved in glutathione metabolism changed during development. gamma-Glutamyltransferase activity increased gradually until day 17 in the liver and eye, but decreased thereafter, while the enzyme activity increased continuously in the kidney. Glutathione reductase and glutathione peroxidase activities did not change significantly during development. Administration of N-nitrosodimethylamine (NDMA) to the fertile eggs 2 days after incubation resulted in an increase of glutathione levels in the liver and kidney at a dose of 0.01 mmol NDMA/egg, but the effect was not significant for glutathione levels by increasing the dose of NDMA. Decrease in viability and increase in formation of thiobarbituric acid (TBA) reactive substance were observed in the liver and kidney by administration of NDMA at 0.1 mmol/egg. By administration of buthionine sulfoximine (BSO) alone, viability and glutathione levels were decreased and TBA reactive substance was increased in the liver. Fatal toxicity of NDMA was observed especially when BSO was administered together with NDMA. These results indicate that glutathione plays an important role in protecting chick embryos against toxic effects induced by administration of NDMA.

Animals↗
PubMed1989

Absence of histochemical immunoreactivity to calcitonin gene-related peptide (CGRP) in spinal cord motoneurons from (+)-tubocurarine-treated chick embryos.

A physiological neuronal death that implicates about 50% of the motoneuron population occurs in the chick embryo between the 6th (E6) and 9th (E9) day of incubation. This natural death can be prevented by administration of neuromuscular blocking agents (e.g. (+)-tubocurarine ((+)-Tc)). In this study, calcitonin gene-related peptide-like immunoreactivity (CGRP-LIR) was studied in spinal cord motoneurons from normal and (+)-Tc-treated chick embryos. In normal embryos CGRP-LIR was found in a neuronal subpopulation of the spinal cord lateral motor column (LMC) that was maximal between the 14th (E14) and 16th (E16) embryonic days with a subsequent decrease. In LMC neurons from (+)-Tc-treated chick embryos examined at E14-16 days no histochemically detectable CGRP-LIR could be observed.

Animals↗
PubMed1979

DNA repair in lens cells during chick embryo development.

When chick lens epithelium is cultured in vitro, differentiation into lens fiber cells is accompanied by DNA degradation. This phenomenom of terminal differentiation was studied in the epithelium from embryos at the 6th and 11th days of development. DNA size and the ability of the cells to repair DNA damage induced by X-rays were analysed in alkaline sucrose gradients. In the 6-day epithelium a rapid degradation and complete lack of DNA repair were recorded. Similar observations have been made in previous studies on the 11-day sample, but here degradation is progressive and occurs after a lag of several days. In the younger epithelium, internal irradiation by [3H]thymidine also had a drastic effect resembling that caused by X-rays. In order to assess the process of differentiation in our experimental system the synthesis of delta- and alpha-crystallins was monitored. Stage-related modifications in the rates of synthesis were recorded. The results confirm that the DNA repair system is impaired during terminal differentiation. The differences observed between the two stages may reflect either a developmental modification in DNA repair mechanisms or a change in the relative proportions of differentiating cells. An hypothesis is proposed in support of the latter case.

Age Factors↗
PubMed1978

Toxicology of triethyllead, methylmercury and cadmium, determined in chick embryo brain cell cultures.

The toxicology of water soluble chemical compounds may be investigated in tissue culture systems. The toxicology of triethyllead chloride, methylmercury chloride and cadmium acetate was studied in chick embryo brain cell cutlures. Tetraethyllead is added to petrol as an anti-knock agent. When tetraethyllead is absorbed by the organism, it is converted to triethyllead which cause the symptoms of tetraethyllead poisoning. Chick embryo brain cell cultures derived from cerebrum of 11-day-old chick embryos developed both neurons and glial cells. The neurons formed nerve processes and synapsis in the cultures. The effect of triethyllead chloride was investigated by addition of triethyllead chloride to the nutrient medium. The median tissue culture lethal dose, TCLD50 = 1.9 mg/l, was determined as the concentration of triethyllead chloride at which the confluent layer of glial cells was destroyed in 50% of the cultures. The neurons lost their processes at even lower concentration, TCED50 = 0.57 mg/l. Electron microscopy revealed cells with swollen Golgi apparatus and dilated endoplasmic reticulum in chick embryo brain cell cultures which were treated with triethyllead chloride, 1.0 mg/l. Studies with radioactive labelled precursors revealed that triethyllead chloride inhibited the synthesis of DNA, sulfatides and cerebrosides without hydroxyfatty acids.

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↗
PubMed2006

Magnetic resonance imaging of iron-oxide labeled SK-Mel 28 human melanoma cells in the chick embryo using a clinical whole body MRI scanner.

PURPOSE: To evaluate advantages and limitations of magnetic resonance imaging (MRI) to monitor the migration of superparamagnetic iron oxide (SPIO) labeled cells in the chick embryo. MATERIALS AND METHODS: Labeled human SK-Mel 28 melanoma cells were injected into the E2 chick embryo neural tube. Embryos were examined with a clinical 3 T MRI whole body system using 3D T*(2)-weighted sequences with isotropic spatial resolutions of 0.3-1.0 mm. MR-measurements of embryos were performed 2 - 16 days after cell injection. MRI findings were verified by dissection and histology. RESULTS: After injection, melanoma cells formed aggregations that were detectable in the neural tube as signal voids in MR images from day 2 after injection. Emigrating cells later left MRI detectable tracks. Aggregates that remained in the neural tube left label that was absorbed by glia cells. In E18 chick embryos, signals of haematopoiesis interfered with signals from cell labeling. CONCLUSION: It was shown that SK-Mel 28 cells will resume the neural crest pathways after injection into the embryonic micro-environment. SPIO cell labeling allows monitoring of transplanted melanoma cells during embryonic development. MRI using the standard clinical equipment promises to be valuable for high-sensitive monitoring of ex-vivo labeled cells in the chick embryo.

Animals↗
PubMed1984

[Streptococcus pneumoniae multiplication in the allantoic cavity of developing chick embryos].

The possibility of the active multiplication of S. pneumoniae (serotypes 1, 3, 6 and 19) in the allantoic cavity of chick embryos has been demonstrated. This multiplication is accompanied by the development of characteristic changes whose intensity and time of manifestation have been found to depend on the infective dose and the age of the embryo. The accumulation of S. pneumoniae in the allantoic cavity of chick embryos in the absence of visible changes in the biological properties of the infective agent after 5 successive subcultures makes it possible to recommend chick embryos as a model for the study of experimental pneumococcal infection.

Allantois↗
PubMed1985

[Aminoglutethimide, an inhibitor of aromatase from chick embryo ovary].

The gonads from 13-day-old female chick embryos were cultured in vitro on TC medium 199, and oestradiol production was measured by radioimmunoassay. In the presence of dehydroepiandrosterone as substrate, oestradiol synthesis was markedly increased, but when aminoglutethimide was also present, it was greatly reduced, depending on the concentration of the drug. This result demonstrates inhibition of the aromatizing enzyme system of the chick embryo ovary by aminoglutethimide in vitro. However, sex differentiation of the female gonads was not modified after in vivo treatment. Since it is not known whether their production is completely suppressed in vivo, the hypothesis cannot be dismissed that oestrogens play a role in ovarian differentiation.

Aminoglutethimide↗
PubMed1986

Opioid elements in development of the spontaneous motility of chick embryos.

The effects of the acute and chronic administration of a pure opioid antagonist--naltrexone--was studied in chick embryos from the 4th to the 19th day of incubation. In acute administration, naltrexone (40 mg/kg egg weight) induced paroxysmal activation of spontaneous motility in both normal and spinal embryos from the 13th-15th day of incubation. Activation attained 3- to 4-fold the resting activity of chick embryos of the same ages. The chronic administration of naltrexone (7.46 +/- 1.18 mg/kg e.w. per 24 h) from the 4th to the 16th day of incubation was not manifested either in the embryos' somatic development or in the weight of the brain hemispheres, but it depressed the development of spontaneous motility to 26.1-75.8% of the activity of the control embryos. This developmental effect was not demonstrably correlated either to the length of time for which naltrexone was administered, or to when, in the course of incubation, it was administered to the chick embryos. The results are evaluated as evidence of the participation of opioid elements in the development and effectuation of central motor input functions in the early stages of ontogenetic development.

Animals↗
PubMed1997

Changes in mean chorioallantoic artery blood flow and heart rate produced by hypoxia in the developing chick embryo.

Hypoxia in the mammalian fetus produces cardiovascular changes, such as bradycardia, systemic hypertension, and changes in heart rate variability. This response was studied in 140 chick embryos ranging from stage 34 to stage 42 (d 9-16 of the 21-d incubation), by measuring the changes in mean chorioallantoic artery blood flow (CABF) and heart rate for 5 min in two levels of hypoxia (group 1; n = 90; 100% N2) or (group 2; n = 50; 5% O2). Eggs were opened at the air cell and placed in a small plexiglass holder, which had a continuous gas flow of an O2/N2 mixture (5 L/min), at 38 degrees C and 60% humidity. The chorioallantoic artery was placed in the lumen of a flow probe to measure mean CABF, heart rate, peak flow, and blood flow acceleration. After baseline measurements, the gas mixture was changed to 100% N2 or 5% O2 in N2 for 5 min. Mean CABF and heart rate decreased significantly in both groups (Wilcoxon paired sample test, p < 0.05). This response was more pronounced with the development of the chick embryo. Chorioallantoic artery peak flow (mL/min) and CABF acceleration (mL/s2) increased with incubation time and decreased during periods of hypoxia. During recovery, heart rate returned to baseline levels, whereas mean CABF showed an overshoot. The initial decrease in mean CABF and heart rate was similar in both groups. The cardiovascular response to hypoxia in the chick embryo is similar to the response in the mammalian fetus. The more pronounced response in the more developed chick embryo may represent a maturation of cardiovascular control.

Allantois↗
PubMed1990

Segmentation in the chick embryo hindbrain is defined by cell lineage restrictions.

In the chick embryo hindbrain, morphological segmentation into rhombomeres is matched by metameric patterns of early neuronal differentiation and axonogenesis. Boundaries between rhombomeres coincide with boundaries of expression of murine regulatory genes. By clonal analysis using intracellular marking, we show here that the rhombomere boundaries are partitions across which cells do not move. When a parent cell is marked before the appearance of rhombomere boundaries, the resulting clone is able to spread into the neighbouring rhombomere. When marked after boundary appearance, the clone still expands freely within the rhombomere of origin, but it is now restricted at the boundaries. Rhombomeres in the chick embryo thus behave like polyclonal units, raising the possibility that they are analogous to the compartments of insects.

Animals↗
PubMed1995

Expression of laminin in vestibular ganglia and nerves in herpes simplex virus infectious chick embryo.

The expression of laminin in the vestibular ganglia and nerves in herpes simplex virus I (HSV-I) infectious chick embryos was examined by immuno-histochemistry. In 9-day-old normal chick embryos, the surface of the vestibular ganglion cells and the vestibular nerves were labelled with laminin, while, in HSV-I infectious chick embryos, the staining of laminin in the vestibular ganglia and nerves was very weak. These results suggest that HSV-I injures vestibular ganglia and nerves, and that laminin is a good marker of the degeneration and innervation of developing vestibular nerves.

Animals↗
PubMed1985

Studies on the cytosolic DNA of chick embryo fibroblasts and its uptake by recipient cultured cells.

Cytosol and extruded DNA complexes from cultured chick embryo fibroblast cells have been separated by agarose gel chromatography at intervals after pulse labelling with [3H]thymidine. The proportion of the various cytosol components changed markedly with time: there was a lag period of 3 hr before the major labelled (5 X 10(5) dalton) DNA complex appeared in the cytosol, and a further lag period of 5 hr before it was extruded from the cell. Cultured chick embryo fibroblast, and rat spleen, cells rapidly and very efficiently import their own or each others cytosolic DNA complexes into their respective cytosol fractions: the material recovered from the cytosol of recipient cells is characteristic of the presented material. Homologous cytosolic DNA complex presented to chick embryo fibroblast cells also becomes associated with the nucleus. The rat at which this occurs is comparable with the rate of incorporation of [3H]thymidine into nuclear DNA.

Animals↗
PubMed1987

Brachial muscles of dystrophic chick embryos atypically sustain interaction with thoracic nerves.

Previous analyses of experimental chick embryos of normal lineage demonstrate the inability of brachial muscles to sustain a successful union with foreign nerves derived from a thoracic neural tube segment transplanted to the brachial region at day 2 in ovo (day 2E). The present experiments were performed to determine if mutant chick embryos afflicted with hereditary muscular dystrophy would respond similarly to this experimental manipulation. Using the same criteria applied to our analysis of experimental normal embryos, our results demonstrated that dystrophic brachial muscles were capable of maintaining a compatible union with foreign thoracic nerves throughout the experimental period analysed. Significant muscle growth occurred, intramuscular nerve branches were maintained, motor endplates formed and wing motility was equivalent to that of unoperated dystrophic embryos. Thus, foreign nerves rejected by normal brachial muscles were accepted by brachial muscles of the mutant dystrophic embryo.

Animals↗
PubMed1984

Immunological evidence for phenobarbital-stimulated synthesis of cytochrome P-450 in primary cultures of chick embryo hepatocytes.

The induction of cytochrome P-450 by phenobarbital was studied in primary cultures of chick embryo hepatocytes. The rate of the de novo synthesis of the induced form of cytochrome P-450 was measured directly and specifically, using form-specific anti-cytochrome antibodies that quantitatively immunoprecipitated this form from the radiolabeled hepatocytes. Additionally, the steady-state levels of the cytochrome were estimated spectrophotometrically and electrophoretically. In the presence of phenobarbital the synthesis of cytochrome P-450PB by cultured hepatocytes was markedly accelerated. Furthermore, the same cytochrome P-450PB form was induced by phenobarbital in vivo in chicken liver and in the cultured chick embryo hepatocytes. Their identity was judged from immunological and electrophoretic properties of these induced cytochromes. Immunological cross-reactivity was also detected between the cytochrome P-450PB forms from chick embryo hepatocytes and from adult rat liver. The immunological cross-reactivity observed between the phenobarbital-induced cytochrome P-450 forms from different species was not observed between the different cytochrome forms with the same liver (Thomas, P.E., Reik, L.M., Ryan, D.E. and Levin, W. (1981) J. Biol. Chem. 256, 1044-1052). Implications as to the evolutionary origin of the different cytochrome forms are discussed.

Animals↗