SEARCH · PubMed Health

Results for “Chick Embryo”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 685 records · Page 38Linked to original sources

PubMed1989

Fine structure and organ culture of chick embryo dorsal aorta.

Embryonic blood vessels have not been grown in organ culture, in a way which might easily submit them to studies of vascular organogenesis. The chick embryo dorsal aorta is easily accessible and relatively simple to explant to culture. Its organ culture may provide a model for wounding and repair of the intima and/or media and provide a model for studies of growth (or maintenance) and differentiation. Fresh dorsal aorta and its organ culture from the chick embryo was characterized morphologically by light microscopy scanning (SEM) and transmission electron microscopy (TEM) from days 4 to 18. Explants were incubated up to 4 days at 37.5 degrees C in normal atmosphere in media including whole chick embryo extract (EE) diluted to 20%. The normal fine structure by SEM shows that as the embryo ages the endothelial cells of the aorta tend to elongate, their microvilli lengthen and increase in size and number up to about 11 days, after which they decrease. TEM also demonstrates an increased differentiation of smooth muscle cells as embryonic age advances. The best culture medium was EE20-Tyrode's. Most of the explants from 14 and 17 days cultured in EE20-Tyrode's contracted into small balls of tissue, endothelial side out. None of these explants showed any significant cellular degeneration. None of the explants survived in EE20-DMEM. Addition of insulin to each medium had no effect on the explants. Intimal cells resembling myofibroblasts were observed in the contracted explants. Using a simple culture condition the chick embryo dorsal aorta can be sustained in organ culture for at least 4 days. The most suitable age for organ culture studies is 9 days (or perhaps somewhat younger); however, it is the most difficult to obtain.

Animals↗

PubMed1991

Coumarin-induced changes in delta-aminolaevulinic acid synthase and cytochrome P-450 in chick embryo liver.

Coumarin occurs naturally in the diet and inhibits several cytochrome P-450 enzymes in laboratory animals. The effect of coumarin was examined on haem biosynthesis and cytochrome P-450 activities in the 18-day-old chick embryo liver in ovo. At 40 and 50 mumol/embryo coumarin increased delta-aminolaevulinic acid synthase, porphyrins, cytochrome P-450, benzphetamine N-demethylase and benzo[a]pyrene hydroxylase. At 10 mumol/embryo coumarin decreased aniline 4-hydroxylase, and at both 10 and 50 mumol/embryo it decreased 7-ethoxyresorufin O-deethylase, coumarin 7-hydroxylase and nitrosodimethylamine N-demethylase. 7-Hydroxycoumarin and 5, 7-methoxycoumarin at 40 mumol/embryo had none of these effects. Coumarin (5-500 microM) added to liver microsomes inhibited aniline hydroxylase by 45%, but not nitrosodimethylamine N-demethylase, and inhibited 7-ethoxyresorufin O-deethylase in microsomes from 3-methylcholanthrene-treated embryos by 15 and 100% at coumarin concentrations of 250 and 500 microM, respectively. Coumarin 7-hydroxylase activity in chick embryo liver was comparable with that reported for human liver and greater than in the rat. The data indicate that coumarin can both increase and decrease cytochrome P-450 activities in chick embryo liver and can induce haem biosynthesis. Because the chick embryo liver hydroxylates coumarin at position 7 in a manner similar to humans, it may be a more suitable model than the rat for studying some of the metabolic effects of coumarin.

5-Aminolevulinate Synthetase↗

PubMedDate not supplied

[The rate of gluconeogenesis and the activity of its key enzymes in the kidneys of the developing chick embryo].

The rate of glucose formation from lactate was studied in tubules isolated from the kidneys of chick embryos of different age and for one- and two-day-old chickens. Changes in the activity of the key enzymes of gluconeogenesis have also been followed in the chick embryo kidneys. The rate of gluconeogenesis markedly increased after hatching. Changes in the rate of gluconeogenesis during embryogenesis are correlated with those in the activity of key enzymes of this process: phospho(enol) pyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase. Glucose-6-phosphatase was shown to be polyfunctional in the kidneys of chick embryos and chickens: in addition to hydrolysis of glucose-6-phosphate with formation of glucose, the enzyme is capable of phosphorylating glucose with the help of phosphate donors, carbamyl-phosphate and pyrophosphate.

Animals↗

PubMed1991

The effect of cardiac cycle length on ventricular end-diastolic pressure and maximum time derivative of pressure in the stage 24 chick embryo.

We hypothesized that developmental increases in both ventricular end-diastolic pressure (EDP) and the maximum time derivative of pressure (dP/dt) observed in stage 12 to 29 chick embryos are the result of observed cardiac cycle length (CL) decrease (heart rate increase). To test this hypothesis, we evaluated EDP and dP/dt changes that occur during acute CL alterations in the Hamburger-Hamilton stage 24 chick embryo (n = 18). Ventricular pressure measurements were obtained with a servo-null pressure system and digitally recorded at 500 samples/s. A 1-mm steel probe, heated (decrease CL) or cooled (increase CL), was applied to the sinus venosus. The average baseline CL was 454 ms. The heart rate perturbation resulted in CL that varied over a range of 200-2966 ms, assimilating the range of CL change observed during development. Changes in EDP ranged from 0.014 to 0.130 kPa (baseline = 0.061 kPa) and maximum dP/dt ranged from 0.33 to 13.33 kPa/s (baseline = 5.99) kPa/s). In each study, EDP varied directly with CL (R2 = 0.70). Conversely, maximum dP/dt changes were inversely related to CL alterations (R2 = 0.54). Thus, we found that there is a direct relationship between changes in CL and EDP in the stage 24 chick embryo, whereas CL and dP/dt vary inversely. During cardiac development, observed increases in maximum dP/dt may be attributed to CL decreases. In contrast, developmental increases in EDP cannot be explained by CL decrease and must be accounted for by maturational changes in cardiac function in the chick embryo.

Animals↗

PubMed1977

Chick-embryo DNA polymerase gamma. Identity of gamma-polymerases purified from nuclei and mitochondria.

The level of DNA polymerase gamma as compared to DNA polymerases alpha and beta has been determined in chick embryo by means of specific tests: the amount of gamma-polymerase in the 12-day-old chick embryo reaches about 15% of the total polymerase activity. This enzyme is mainly localized in nuclei and mitochondria, where it represents the prevailing if not the unique DNA polymerase activity. The mitochondrial DNA polymerase gamma is likely to be associated with the internal membrane or the matrix of this organelle since it is not removed by digitonin treatment. The gamma-polymerases have been purified from chick embryo nuclei and mitochondria 500-700 times by means of DEAE-cellulose, phosphocellulose and hydroxyapatite chromatographies. The purified mitochondrial DNA polymerase gamma is closely related to the homologous enzyme purified from the nuclei of the same cells. So far, they cannot be distinguished on the basis of their sedimentation, catalytical properties and response to inhibitors or denaturating agents. The purified gamma enzymes are distinct from the chick embryo DNA polymerases alpha and beta and are not inhibited by antibodies prepared against the latter enzymes. The nuclear and mitochondrial gamma-polymerases do not respond to the oncogenic RNA virus DNA polymerase assay with natural mRNAs.

Animals↗

PubMed1992

Development of the endolymphatic sac in chick embryos, with reference to the degradation of otoconia.

The endolymphatic sac of chick embryos (from embryonic day 7 to 1-day-old chicks) was studied light- and electron-microscopically. At stage 30-31 (embryonic day 7-7.5), the epithelial cells of the endolymphatic sac were cuboidal to columnar in shape. Microvilli were relatively well developed. The intercellular space was wide. In the endolymphatic space of the endolymphatic sac, varying shapes and sizes of otoconia-like bodies were often observed. Intracytoplasmic phagosomes containing these bodies were rarely found. After stage 37 (embryonic day 11), otoconia-like bodies in the endolymphatic sac decreased in number and size. They were almost the same as the otoconia in the macular organs, ultrastructurally. These findings indicate that the endolymphatic sac of the chick embryos may possess the function of otoconial degradation and removal of calcium from otoconia.

Animals↗

PubMed1975

Spontaneous and induced mutagenesis in Western Equine encephalomyelitis virus in chick embryo cells with different repair activity.

Evidence was obtained indicating differences in the survival rate of Western equine encephalomyelitis virus after exposure to ultraviolet radiation and methyl methanesulfonate in commercial and leukosisfree chick embryo cells that differed in repair activity. The levels of spontaneous mutagenesis (on the basis of the yield of small palque variants of the encephalomyelitis virus) did not essentially change when the virus was passage in leukosis-free chick embryo cells, whereas an increase in the number of small palque variants was observed in the cells of commercial chick embryos. A 10-fold increase in the number of induced virus variants was observed in commercial chick embryo cells in experiments with methyl methanesulfonate as compared with the contorl, whereas the induction of virus variants was not noted in leukosis-free cells.

Animals↗

PubMed1984

Isoproterenol--induced damage to the liver of chick embryos.

Isoproterenol has been shown to cause severe liver damage in chick embryos. Most severe lesions were observed in embryos 10 to 12 days old, which showed extensive parenchymal necrosis. In older embryos, the lesions were mostly represented by areas of fatty degeneration. In 6 to 9-day-old embryos, the changes were indistinct (slight). The necrotic foci underwent slow resorption with disperse dystrophic calcification. Surviving hepatocytes around the damaged areas revealed some regenerative phenomena. The possible cause of marked hepatotoxicity of isoproterenol for chick embryos is discussed.

Animals↗

PubMed1985

Morphometric and autoradiographic analysis of frontonasal development in the chick embryo.

Dimensional changes in the nasal processes were measured in chick embryos from Hamburger and Hamilton (1951) stages 20 through 27.5. Transverse measurements in the frontonasal region of freshly fixed embryos were compared to frontal sections of the nasal region of comparably staged embryos. These observations were correlated with autoradiographic studies of cell movement employing an implant labeling technique. Morphometric analysis indicated that between stages 20 and 25 the separation of the nasal pit orifices increased coincidentally with rapid forebrain enlargement. Since the separation of the nasal pit fundi increased more rapidly, the orientation of the nasal pits changed. Autoradiographic studies indicated that lateral movement of medial nasal process mesenchyme into the base of the nasal groove and medial area at the base of the lateral nasal process had occurred. After stage 25, the separation of the nasal orifices declined dramatically, coincidental with rapid orbital enlargement. In contrast, the separation of the nasal pit fundi was maintained. It is proposed that nasal development of the chick embryo may be governed initially by forebrain enlargement and associated lateral movements of mesenchyme in the medial nasal processes, resulting in reorientation of the invaginating nasal placodes; subsequently, orbital enlargement and an associated medial redirection of growth of the lateral nasal processes assumes greater significance to the continued development of the frontonasal region.

Animals↗

PubMed1985

Stimulatory and persistent effect of acute hyperoxia on respiratory gas exchange of the chick embryo.

The hypothesis that oxygen availability limits growth of the normal chick embryo late in development predicts that an increase in oxygen availability would accelerate the rate of growth and, therefore, metabolism. We tested the prediction concerning metabolism by comparing the oxygen consumption (VO2) and carbon dioxide production (VCO2) of 14-18 day embryos acutely exposed to either 50% or 100% O2 with those of normoxic (21% O2) controls. Two hours of hyperoxia produced increases in both VO2 and VCO2; however, repeated measurements over time in normoxia also demonstrated a significant increase in gas exchange, presumably due to normal growth of the embryos. After correcting for the increase in VO2 due to growth, there was no effect of 60% O2 on day 14. Thereafter the stimulatory effect of 60% O2 increased gradually, reaching 6.1% on day 18. VCO2 was 4 to 6% higher in embryos acutely exposed to 60% O2 than in normoxic controls throughout the observation period, although the difference was significant only on day 18. The VO2 of embryos acutely exposed to 100% O2 was not significantly different from that observed in 60% O2, and was still significantly elevated 3 h after the eggs were returned to 21% O2. We conclude that acute hyperoxia late in incubation elicits an increase in embryonic VO2 and VCO2, with little or no effect on the respiratory exchange ratio, and that the stimulation of gas exchange by 100% O2 persists after the embryo is returned to normoxic conditions. These findings support the hypothesis that oxygen availability limits growth and metabolism of the normoxic chick embryo late in development.

Animals↗

PubMed1982

Xylosylphosphoryldolichol synthesized by chick embryo epiphyses. Not an intermediate in proteoglycan biosynthesis.

Incubation of chick embryo epiphyseal microsomes with UDP-[14C]xylose in the presence of pyrophosphatase inhibitors resulted in the incorporation of [14C]xylose into proteoglycan and the formation of small amounts of 14C-labeled material soluble in chloroform:methanol. Synthesis of the [14C]xylose-lipid was stimulated by exogenous dolichol phosphate whereas the addition of retinol plus ATP had no effect. The [14C]xylosyl-lipid was identified as [14C]xylosylphosphoryldolichol by chromatography on SG-81 paper and DEAE-cellulose and by acid hydrolysis. Addition of UDP-galactose and UDP-glucuronic acid to incubations of epiphyseal microsomes with UDP-[14C]xylose did not stimulate [14C]xylose incorporation into lipid nor into proteoglycan. Under several different conditions, [14C]xylose was not transferred from [14C]xylosylphosphoryldolichol to proteoglycan, indicating that [14C]xylosylphosphoryldolichol was not an intermediate in proteoglycan biosynthesis. Chick embryo epiphyseal microsomes also synthesized [14C]glucosylphosphoryldolichol. In addition, [14C]glucose was transferred from [14C]glucosylphosphoryldolichol into oligosaccharide lipids in the chloroform:methanol:water extract and into glycoproteins in the pellet fraction. Competition experiments with UDP-glucose and UDP-xylose suggested that xylosylphosphoryldolichol was synthesized by the glucosyltransferase involved with glucosylphosphoryldolichol biosynthesis.

Animals↗

PubMed2000

Molecular characterization and developmental expression of the aryl hydrocarbon receptor from the chick embryo.

The aryl hydrocarbon receptor (AhR) was cloned from the chick embryo and its function and developmental expression characterized. Chicken AhR cDNA coded for 858 amino acid protein and 396 bp of 3' UTR. The basic helix loop helix domain exhibited 87-100% amino acid identity to avian, mammalian, and amphibian AhR, and 69-74% to piscine AhR. The PAS (Per-ARNT-Sim) region was slightly less well conserved with (a) 97% identity to other avian sequences, (b) 81-86% to amphibian and mammalian AhR, and (c) 64-69% with piscine AhR. The carboxy terminus diverged the most among species with less than 53% amino acid identity between chicken and any available mammalian and piscine AhR sequences. The chicken AhR RNA and protein were 6.1 kb and 103 kDa, respectively. Chicken AhR dimerized with human AhR nuclear translocator and bound the mammalian dioxin-response element in a ligand-dependent manner. AhR protein was detected in neural ganglia; smooth, cardiac, and skeletal muscle; and epithelium involved in epithelial-to-mesenchymal transformations, such as pituitary, gastrointestinal tract, limb apical-ectodermal ridge, and kidney collecting ducts. AhR mRNA was detected in all tissues expressing protein, except myocardium. Cytochrome P4501A4 mRNA was highly induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in a subset of tissues expressing AhR, including small intestine, liver, kidney, blood vessels, and outflow tract myocardium. In conclusion, the AhR sequence and function is highly conserved between birds and mammals, and although many tissues express AhR during chick embryo development, only a subset are responsive to TCDD induction of CYP1A4.

Amino Acid Sequence↗

PubMed1996

The chorioallantoic artery blood flow of the chick embryo from stage 34 to 43.

Chorioallantoic artery blood flow and heart rate were studied in the chick embryo from stage 34 until stage 43 (d 9-16 of 21-d incubation). Baseline blood flow profiles of the chorioallantoic artery were measured with a flow probe (Transonic) in 100 chick embryos. The eggs were opened at the air cell and placed in a small plexiglass box with a continuous gas flow of a N2/O2 mixture (5 L/min), at 38 degrees C and 60% humidity. The chorioallantoic artery was localized near the fetal abdomen and placed in the lumen of the Transonic flow probe. The heart rate was derived from the blood flow signal. The mean chorioallantoic artery blood flow rose from 0.35 +/- 0.14 mL/min (mean +/- SD) at stage 34 to 3.13 +/- 1.49 mL/min at stage 43 (R2 = 0.69, p < 0.0001), which correlated with an increase in body weight (1.51 +/- 0.18 g to 15.08 +/- 0.76 g). Heart rate increased from 195 +/- 38 beats/min at stage 34 to 289 +/- 13 beats/min at stage 43 (R2 = 0.38, p < 0.0001). The chorioallantoic artery blood flow, which in avian species correlates with umbilical blood flow in mammals, increased with incubation time as reported in the mammalian fetus. This study shows that the chick embryo could be useful as a preparation for further perinatal cardiovascular research.

Allantois↗

PubMed1998

Use of chick embryo in screening for teratogenicity.

A teratology screening system would detect agents hazardous to the conceptus before they can perturb embryonic development in humans. The back log of untested chemicals and the rate at which new substances enter the market exceed the developmental effects testing by standard in vivo method. Thus, cheaper, quicker in vitro systems afford a unique opportunity for investigating the direct interaction of substances with developing morphogenetic system (MGSs), since maternal influences are excluded. As a carrier of a complete set of MGSs, the chick embryo in ovo manifests an advantage over those in vitro systems that employ isolated embryos or embryonic tissues that have only limited survival. Under controlled experimental conditions including standardization of subjects, administration technique and mode of evaluation, according to the basic principles of teratology, the chick embryo test is demonstrated to be reliable and to afford quantifiable end points for evaluation. Individual compounds, mixtures of compounds and against and antagonist can easily be administered and tested. The chick embryo possesses its own basic enzyme-catalyzed drug-transformation capacity and moreover, it can be used for screening specific human metabolites. Different newer techniques e.g. chick embryotoxicity screening test (CHEST), Chick embryo blastoderm model etc are described in detail. Chick embryo fulfills all the criteria which a test should have at a lower level of tier system in teratological studies i.e. modest laboratory equipment, moderate skill, minimal expenditure of time and money, ease of accessibility of embryo, known embryological development, possibility of experimenting on a large scale for statistically valid results and whole animals are also not required.

Animals↗

PubMed1978

Enzymes involved in adenine nucleotide metabolism of developing chick embryo liver.

1. This paper describes the changes in the activity of adenylate deaminase, adenylate and inosinate phosphatase, and adenosine deaminase in the developing chick embryo liver. 2. The adenylate and inosinate phosphatase and adenosine deaminase activity appears considerably higher in chick embryo liver with respect to other chick embryo tissues previously examined. 3. During development the control exerted by ATP on AMP breakdown undergoes variations. Consequently, in the first period of incubation AMP is degraded by the direct pathway (AMP-IMP) and in the last period of incubation by the indirect pathway (AMP-adenosine). In the intermediate period (from the 12th to the 15th day of incubation) both pathways may be followed. 4. The ability to synthesize purine nucleotides through "salvage pathway" seems to be acquired by embryonic liver at least at the 15th day.

5'-Nucleotidase↗

PubMed1995

An in vitro culture method for chick embryos obtained from the anterior portion of the magnum of oviduct.

1. Chick embryos, obtained from the anterior portion of the magnum of the oviduct 60 to 80 min after the preceding egg had been laid, were cultured in vitro in small and large recipient eggshells until hatching. 2. Of 82 embryos cultured, 46.3% had survived to day 4 of incubation, and 19.5% survived to hatching. 3. The method for culturing embryos used in this experiment could facilitate research on the in vitro manipulation of early chick embryos.

Animals↗

PubMed2004

Ventricular diastolic filling characteristics in stage-24 chick embryos after extra-embryonic venous obstruction.

Alteration of extra-embryonic venous blood flow in stage-17 chick embryos results in well-defined cardiovascular malformations. We hypothesize that the decreased dorsal aortic blood volume flow observed after venous obstruction results in altered ventricular diastolic function in stage-24 chick embryos. A microclip was placed at the right lateral vitelline vein in a stage-17 (52-64 h of incubation) chick embryo. At stage 24 (4.5 days of incubation), we measured simultaneously dorsal aortic and atrioventricular blood flow velocities with a 20-MHz pulsed-Doppler velocity meter. The fraction of passive and active filling was integrated and multiplied by dorsal aortic blood flow to obtain the relative passive and active ventricular filling volumes. Data were summarized as means +/- S.E.M. and analyzed by t-test. At similar cycle lengths ranging from 557 ms to 635 ms (P>0.60), dorsal aortic blood flow and stroke volume measured in the dorsal aorta were similar in stage-24 clipped and normal embryos. Passive filling volume (0.07+/-0.01 mm(3)) was decreased, and active filling volume (0.40+/-0.02 mm(3)) was increased in the clipped embryo when compared with the normal embryo (0.15+/-0.01 mm(3), 0.30+/-0.01 mm(3), respectively) (P<0.003). In the clipped embryos, the passive/active ratio was decreased compared with that in normal embryos (P<0.001). Ventricular filling components changed after partially obstructing the extra-embryonic venous circulation. These results suggest that material properties of the embryonic ventricle are modified after temporarily reduced hemodynamic load.

Animals↗

PubMed1988

[Response to antitumor agents of human transplantable glioma implanted into chorioallantoic membrane of chick embryo].

In case of chemotherapy against brain tumors, it is most important to choose suitable drugs for brain tumors, since human tumors have different drug sensitivity and growth. Heretofore, the nitrosourea-induced rat glioma cell, such as C6, or immunodeficient mice were usually used for predicting the drug sensitivity of brain tumors. We took notice of Murphy's system for the chemosensitivity test, in which a human tumor is transplanted into the chorioallantoic membrane (CAM) of a chick embryo. By modifying the conventional Murphy's system, we studied the efficiency of this system in predicting the drug sensitivity of brain tumors. First, we compared the result of a drug sensitivity test using CAM of a chick embryo with that using nude mice. Next we studied the effect of chemotherapeutic agents against brain metastasis of a chick embryo caused by the intravenous injection of mouse B16 melanoma cells. The tumor reduction rate of the sensitivity test using a chick embryo tended to agree with that using nude mice. In the drug sensitivity test against brain metastasis, ACNU was the most effective. This result supports the result of the clinical study. In conclusion, the drug sensitivity test using a chick embryo is thought to be useful and the advantages or disadvantages of this system are discussed.

Allantois↗