PubMed Health⌕ Search

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 235 records · Page 13Linked to original sources
PubMed2000

Different physiological mechanisms control isovolumetric regulation and regulatory volume decrease in chick embryo cardiomyocytes.

Cultured chick embryo cardiac myocytes submitted to a 180 mOsm/kg hyposmotic solution swell present a regulatory volume decrease (RVD). This RVD is mediated by a Ca(2+)influx followed by a 40% loss of total taurine content accompanied by the loss of lesser amounts of other osmolytes. Kidney cells respond to a gradual change in osmolality by maintaining their volume at the initial level. This is termed isovolumetric regulation (IVR), which may activate regulatory processes other than those observed with sudden changes in osmolality. When cardiac myocytes were exposed to a gradual change in osmolality, they show a partial IVR which is not dependent upon extracellular Ca(2+). Potassium channel blockers, quinidine and Ba(2+), and the chloride channel blocker, diphenylamine-2-carboxylate (DPC), compromise IVR in our model. Tritiated taurine loss and total intracellular K(+)contents were analyzed in cultured cardiomyocytes submitted to a gradual change in osmolality. The cultured cells lost approximately 10% of their taurine and 35% of their total K(+). These findings suggest that different compensatory mechanisms are activated when cells are exposed to stepwise and gradual changes in osmolality. Inorganic osmolytes (through conductive pathways) are preferentially mobilized during the physiological and/or patho-physiological IVR situation, perhaps reflecting energetic conservation in response to a less traumatic event for the cardiac myocytes.

Animals↗
PubMed1985

The influence of stress and strain in the early development of shaft bones. An experimental study on the chick embryo tibia.

In chick embryos from stage 23 to stage 27 the whole presumptive zeugopod - or its pre-axial (tibial) portion only - was proximodistally and dorsoventrally inverted by turning it 180 degrees round the anteroposterior axis of the limb bud. Development of the reoriented blastema of the tibia was consistently retarded and variously reduced: this skeletal piece appeared shorter and relatively thicker than the controlateral normal tibia. Chondrification, progress of differentiation of the cartilaginous model, onset and gradual spreading of the ossification processes were considerably delayed. Often the diminutive tibia underwent a degree of bending or angulation of up to 90 degrees - 100 degrees in the sagittal plane. In these bent tibiae - obviously developing under abnormal conditions of intrinsic and extrinsic mechanical stresses - cell hypertrophy appeared greatly retarded or hindered in sites of the diaphysial cartilaginous core which were presumably subjected to strong longitudinal compression. No rigorous temporal and topographical relationships were observed between chondrocyte hypertrophy and onset of perichondral osteogenesis. Apparently, a direct contact between hypertrophic cartilage and perichondrial cells was not strictly required to prompt osteogenesis; this process, in fact, often involved areas of the perichondrium enveloping parvicellular cartilage. Radial pressures exerted by the over-stretched outer layer of the perichondrium, or periosteum, on the subjacent prospective osteogenous layer reduced or prevented the deposition of bone. Conversely, radial stretching of the inner layer of the perichondrium, or periosteum, considerably enhanced cell proliferation, blood vessel formation, differentiation of osteoblasts and formation of bone matrix.

Animals↗
PubMed1982

The adverse effects of HEPES, TES, and BES zwitterion buffers on the ultrastructure of cultured chick embryo epiphyseal chondrocytes.

Chick embryo epiphyseal chondrocytes cultured in media containing HEPES, TES, and BES zwitterion buffers, used in combination or independently, consistently developed cytoplasmic vacuoles. This cytoplasmic vacuolation was resolved when the zwitterion buffered media was replaced by media containing bicarbonate:CO2 enriched air buffer. Vacuoles were infrequent or absent in cultures grown in bicarbonate:CO2 enriched air. Chondrocytes with an established extracellular matrix showed less vacuolation than fibroblastlike and polygonal shaped cells that lacked such a matrix. The granular endoplasmic reticulum and Golgi dictyosomes of zwitterion buffered chondrocytes were distended and contained a flocculent amorphous material. Cytoplasmic vacuoles (0.5 to 3.0 micron diam) formed by the fusion and intracellular accumulation of Golgi vesicles and vacuoles also contained a flocculent material enhanced by ruthenium red. Membrane bound extracellular vacuoles containing ruthenium red stained proteoglycan aggregates were common in the extracellular matrix of zwitterion buffered cultures but were generally absent from bicarbonate treated cultures. Electron dense calcium deposits seemed much larger and more numerous in the presence of zwitterion buffers. It is suggested that HEPES, TES, and BES buffers, used alone or in combination, may adversely affect cell membrane systems, and thus the transport or secretory mechanisms operative in cultured chondrocytes, or both, resulting in vacuole formation and the intracellular accumulation of synthesized export material. Although the mechanism by which HEPES, TES, and BES induce these changes remains unclear, the use of zwitterion buffers in biological preparations should be treated with caution.

Alkanesulfonates↗
PubMedDate not supplied

Phosphorylation and protein kinase activities of chromosomal non histone proteins from chick embryo fibroblasts.

Confluent chick embryo fibroblasts were cultured in vitro in (i) medium which prevented the cells from dividing, (ii) medium which stimulated the cells to divide synchronously, (iii) medium without lysine in which the cells were blocked in G1. Chromosomal non histone proteins (NHP) were extracted from cells pulse labelled with 32P phosphate, and the radioactivity analyzed by acrylamide gel electrophoresis. Several radioactive peaks were found all along the gel in the NHP from confluent and stimulated cells. The highest phosphorylation was found in the fast moving proteins, but the stimulation of the cells increases the phosphorylation of the slower moving proteins. In the NHP from cells cultured in the medium without lysine only the slow migrating proteins were phosphorylated. NHP were extracted from unlabelled cell cultures in the three different media, incubated with [gamma-32P] ATP and analyzed by acrylamide gel electrophoresis. Highly labelled peaks were observed in the fast moving proteins from stimulated cells and from cells cultured in a medium deprived from lysine. By comparing in vivo and in vitro phosphorylation, it can be concluded that in confluent cells the turnover of bound phosphate is slow. In stimulated cells there is a fast turnover of the phosphate bound to fast turnover of the phosphate bound to a small group of fast migrating proteins and very little turnover of the phosphate bound to slow migrating proteins. The cells were incubated with labelled lysine and NHP analyzed by gel electrophoresis. The radioactivity of individual NHP varied with the culture conditions, but in all cases, there was little radioactivity in the fast moving proteins. The phosphate groups submitted to a fast turnover are bound to stable proteins. Phosvitin and casein kinase activities were measured in the NHP fractions. Nine-ten peaks of activities were observed with each substrate. Some variations were observed which apparently correlate with the culture conditions.

Adenosine Triphosphate↗
PubMed1986

Regulation of extraembryonic calcium mobilization by the developing chick embryo.

During development, the chick embryo mobilizes the calcium it needs from two extraembryonic sources, first the yolk and then the eggshell. Since previous studies have strongly suggested that vitamins D and K may regulate chick embryonic calcium metabolism, we have examined here how these vitamins might be involved in regulating the calcium mobilization processes. We used as our experimental system chick embryos which were maintained in long-term in vitro culture in the absence of the eggshell. Our results showed that exogenous vitamin D3, in the form of the active 1,25-dihydroxylated metabolite, was hypercalcaemic in both control embryos and the calcium-deficient, shell-less embryos. Since the eggshell was absent in the latter, the vitamin D-induced hypercalcaemia must involve mobilization of calcium from the yolk and, or, the embryonic skeleton. The latter was unlikely since concomitant hyperphosphataemia was not observed. By radiolabelling the yolk with 45Ca2+ and subsequently monitoring its distribution, we showed that vitamin D3 stimulated yolk calcium mobilization. However, exogenous vitamin D3 did not appear to influence the calcium uptake activity of the chorioallantoic membrane (CAM), the tissue responsible for translocating eggshell calcium. On the other hand, when embryos were rendered vitamin K deficient by the administration of its antagonist, Warfarin, CAM calcium activity was significantly depressed, an effect which was remedied by vitamin K supplementation. We conclude that, during normal chick embryonic development, vitamin D is primarily involved in regulating yolk calcium mobilization whereas vitamin K is required for eggshell calcium translocation by the CAM.

Allantois↗
PubMed2005

Toxic interactions between fluconazole and disopyramide in chick embryos.

The present study evaluated the effect of fluconazole on the heart, as well as and the toxic interactions between fluconazole and disopyramide in chick embryos. Chick embryos have been widely used in pharmacologic and toxicologic experiments for evaluating drug action. Fertilized eggs of White Leghorns were incubated and investigated. Fluconazole 0.4 mg/egg, 0.8 mg/egg, 1.2 mg/egg alone or disopyramide 0.3 mg/egg alone was injected into the air sac of each fertilized egg. And fluconazole 0.4 mg/egg with disopyramide 0.3 mg/egg was injected into the air sac of each fertilized egg. Electrocardiograms (ECGs) were recorded 0 to 60 min after the drug injection, and heart rate was determined from ECG wave cycles. Changes in heart rate were expressed as mean-percent changes of the drug-treated groups to the matched control. After the administration of fluconazole 0.4 mg/egg alone, the heart rate did not differ compared with that of the controls. However, the heart rate was significantly decreased with the administration of fluconazole 0.8 mg/egg and 1.2 mg/egg. The heart rate was also significantly decreased by the administration of fluconazole 0.4 mg/egg together with disopyramide 0.3 mg/egg. In addition, an arrhythmia was produced by fluconazole and disopyramide. These findings indicate that the interaction between fluconazole and disopyramide has a marked influence on the heart rate in chick embryos.

Animals↗
PubMed1982

Optimum conditions for growth and longevity of chick embryo fibroblasts in culture.

Chick embryo fibroblasts are often used as a model of cellular ageing in vitro. It seems important to culture these cells in optimum conditions which may not be the same as those for mammalian cells. An incubation temperature of 40 degrees C and the use of chicken serum were found to be optimum for growth and longevity of chick embryo fibroblasts in culture.

Animals↗
PubMed1997

Induction of additional limb at the dorsal-ventral boundary of a chick embryo.

In the early chick embryo, an apical ectodermal ridge (AER) is formed from the overlying ectoderm of the presumptive limb bud region at the dorsal-ventral (DV) boundary. We report here that the ectopic DV boundary formed in the presumptive wing, flank, and leg fields induces an ectopic AER structure. Dorsal tissue (ectoderm and mesoderm) from the presumptive wing field of stage 10 to 17 embryos was inserted into a slit in the somatopleure of the future ventral side of host embryos. The same method was used to implant ventral tissue into the future dorsal side of host embryos. After the implantation, ectopic AER was induced and an additional limb or limb-like structure developed. In related experiments, ectoderm-free presumptive wing tissue was implanted, which resulted in a considerably decreased frequency of ectopic AER formation. Further analysis of chick and quail chimeras suggests that the ectopic AER was formed from the ectodermal cells overlying the boundary of host and graft mesodermal cells. These results indicate that the DV boundary organizes the AER structure in the limb bud field of early-stage chick embryos and that the ectoderm of the grafted tissues plays an important role in this process.

Animals↗
PubMed1991

Lethal and teratogenic effects of long-term low-intensity radio frequency radiation at 428 MHz on developing chick embryo.

Exposure of developing chick embryos to 428 MHz radio frequency (RF) radiation at a power density of 5.5 mW/cm2 for more than 20 days resulted in embryolethal and/or teratogenic effects and delayed hatching. These adverse biological effects were not due to any thermal effect of the RF radiation. We have demonstrated teratogenicity in the chick embryo as a result of protracted low-dose RF irradiation.

Abnormalities, Radiation-Induced↗
PubMed1972

Age-associated changes in fecal excretion patterns of strain 93 chick embryo lethal orphan virus in chicks.

Oral incoulation of chickens with strain 93 (chick embryo lethal orphan) virus produced a subclinical infection of the gastrointestinal tract. The pattern of fecal virus excretion in birds infected at 4 or more weeks of age (adult pattern) differed from that in chicks infected when newly hatched (juvenile pattern). By comparison with the juvenile pattern, the adult pattern was characterized by lower peak titers of fecal virus, earlier decline in virus titer, and shorter duration of excretion. Quantitative studies on hatchmates infected at various ages showed that these characteristics are established sequentially with age: lower peak titers were observed in birds infected at 2 to 4 days of age; early decline in titer was first observed in birds infected at 14 days of age; and curtailed excretion was observed in birds infected at 21 days of age. Possible mechanisms operative in the autosterilization process are discussed.

Adenoviridae↗
PubMed1990

Action of 1,25-dihydroxyvitamin D3 and parathyroid hormone on 45calcium uptake by the yolk sac membrane of chick embryos.

During development, the chick embryo mobilizes the calcium it needs from two extraembryonic sources, initially from the yolk and later from the eggshell. Calcium may be hormonally regulated during avian embryogenesis, but details of this regulation are lacking. We investigated the effects of 1,25-dihydroxycholecalciferol [1,25(OH)2D3], bovine parathyroid hormone [bPTH], and vehicle [ethanol or saline] on blood calcium values and incorporation of 45Ca into the yolk sac membrane of 9, 12, and 15 day chick embryos. Control data were also collected from uninjected 6 day embryos. Solutions were injected directly into the yolk sac compartment 48 and 24 hours prior to the experiment. Exogenous 1,25(OH)2D3 induced hypercalcemia in all age groups examined, while exogenous PTH induced hypercalcemia in day 12 and 15 embryos. Small disks of yolk sac membrane were incubated in medium to which 45Ca was added and assayed for 45Ca content at various intervals after start of incubation. In control yolk sac tissue, the uptake of 45Ca was greatest in younger embryos with decreasing uptake at developmentally more advanced ages; 1,25(OH)2D3 treatment significantly enhanced the uptake of 45Ca into yolk sac tissue in all groups (9, 12, and 15 day embryos). PTH treatment caused a significant elevation in 45Ca uptake in the day 12 and 15 embryos.

Aging↗
PubMed1975

Physiological effects of hypoxia and trypan blue in 17-day chick embryos.

Seventeen-day chick embryos were divided into 5 groups and treated as follows: (1) untreated, (2) yolk-sac injected with 0.1 ml of saturated trypan blue solution solution in sterile saline, (3) saline, (4) hypoxia, i.e., 10.5% oxygen, and (5) hypoxia plus trypan blue. After 5 h hypoxia-treated embryos had an increased mortality rate, severe hypoglycemia, reduced blood pH, elevated plasma potassium, and reduced CO2 content. Trypan blue treatment induced few deaths and few physiological imbalances. Hypoxia plus trypan blue was without synergistic effects and had effects that did not differ significantly from hypoxia alone. This lack of response of 17-day chick embryos to high doses of trypan blue may be related to a marked decline in oxygen consumption by the yolk at this age.

Animals↗
PubMed1995

Ultrastructural and immunocytochemical evidence for the presence of polarised plasma membrane H(+)-ATPase in two specialised cell types in the chick embryo chorioallantoic membrane.

The chick embryo, confined in the eggshell, has to dispose/buffer the acid generated by its metabolism, as well as to release calcium from the shell which is used for growth. To localise H(+)-ATPase, electron microscope and immunocytochemical studies were conducted on chorioallantoic membranes of 15-17 d chick embryos. Ultrastructural studies of the villus cavity (VC) cells in the chorionic epithelium demonstrated that their apical plasma membrane, juxtaposed with the shell membranes, contains microvilli as well as microplicae which possess 9-10 nm studs at a density of 16,700 particles/micron2, a characteristic feature of the polarised H(+)-ATPase pump. Immunocytochemical staining, using a monoclonal antibody to the 31 kDa subunit of H(+)-ATPase, confirmed the presence of large amounts of the vacuolar H(+)-ATPase in the VC shells with a distribution highly polarised towards the eggshell membranes. Immunoelectron-microscopic localisation studies using a rabbit antiserum to whole bovine H(+)-ATPase and immunogold technique, confirmed the localisation of H(+)-ATPase at the apical microvilli/microplicae as well as in the subapical vesicles. In the allantoic epithelium, the presence of mitochondria-rich (MR) cells was confirmed; it was shown that these cells extend through the full thickness of this epithelium. The MR cells also contained large numbers of 9-10 nm studs, typical of proton secreting cells, in their apical plasma membrane. This was confirmed by immunocytochemical staining which showed abundant localisation of H(+)-ATPase in these cells; this localisation was, however, diffuse rather than apical.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1998

Molecular cloning, characterization, and expression of the chicken heme oxygenase-1 gene in transfected primary cultures of chick embryo liver cells.

Using chick heme oxygenase-1 (cHO-1) cDNA as a probe, three independent clones were identified from screening a lambda FixII chick genomic library. Genomic Southern blots using this cDNA probe or a cHO-1 5' specific probe showed that cHO-1 is a single-copy gene. Based on restriction enzyme analysis, Southern blots, polymerase chain reaction analysis and DNA sequencing, it was confirmed that the three overlapping clones isolated cover the entire cHO-1 gene, as well as approximately 10 kb of the flanking regions on both ends. As with mammalian HO-1x, cHO-1 has five exons and four introns. Computer analysis of the DNA sequence obtained identified consensus sequences corresponding to numerous transcription factor recognition elements. These include AP-1, AP-2, NF-kB, C/EBP, c-Myc and a metal-responding element identified in the promoter region, and two Sp-1 elements in intron 1. Transient expression studies in transfected primary cultures of chick embryo liver cells showed that a CAT reporter gene construct containing 2.8 kb of the cHO-1 promoter region responded to sodium arsenite, H2O2, transition metals and 12-0-tetradecanoylphorbol 13-acetate, but not to heme. Studies with deletion mutants, consisting of various lengths of the cHO-1 promoter region, indicated that there are two regions important for sodium arsenite induction, one located between residues -1642 and -1293, and the second located in the first 263 base pairs of the cHO-1 promoter. DNA binding studies by electrophoretic mobility shift assay showed that nuclear protein isolated from primary cultures of chick embryo liver cells bound to the oligonucleotide probe containing an AP-1 element identified at -1573 to -1580. In addition, such binding was increased by cobalt or sodium arsenite treatment.

Animals↗
PubMed1977

Levels of translatable mRNAs for cell surface protein, collagen precursors, and two membrane proteins are altered in Rous sarcoma virus-transformed chick embryo fibroblasts.

Transformation of chick embryo fibroblasts by Rous sarcoma virus results in decreased amounts of a major cell surface protein and of collagen. To determine the mechanism accounting for the decreased production of these proteins, we have measured the relative amounts of functional mRNAs for these and other transformation-sensitive proteins. Total cellular RNAs extracted from normal cells and from cells transformed by the Schmidt-Ruppin strain of Rous sarcoma virus were translated in a cell-free system derived from wheat germ. Analysis of the in vitro translation products of RNAs from normal and transformed chick embryo fibroblasts shows a 5-fold reduction in the translatable mRNA for cell surface protein and a 10-fold reduction in translatable mRNA for two collagen precursors. In addition, increases in functional mRNA are observed for myosin and for two membrane polypeptides with molecular weights of 95,000 and 78,000; the latter two proteins increase on transformation, but the increases are in large part secondary to the depletion of glucose from the medium of transformed cells. Our data suggest that some of the major cellular changes induced by oncogenic viruses are due to changes in the activity of specific cellular genes.

Actins↗