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PubMed2003

Growth retardation and lethality induced by adriblastina in chick embryo.

The low (1.2 mg/kg) and high (2.4 mg/kg) therapeutic dose of adriblastina, dissolved in 0.04 ml of distilled water was injected into the chick embryo at different duration of the incubation. The control chick embryo received equal volume of distilled water at the same duration. All groups of embryo were collected on day 19 of gestation. The treated embryo showed growth retardation and lethality in a dose dependence response. The lethality and growth retardation in both treated groups were found significantly different (p<0.001) as compared with the control chick embryo. Similarly the groups treated on different days showed a time sequential effect on the developing chick embryo. Our observation had revealed that the drug is teratogenic to the chick embryo.

Animals↗

PubMed1985

Cytoplasmic vitamin A binding proteins in chick embryo dermis and epidermis.

Excess vitamin A has striking morphologic and developmental effects on chick embryo skin. While cytoplasmic retinoic acid-binding protein (CRABP) was known to be abundant in chick embryo skin, neither quantitative values nor the distribution between dermis and epidermis have been established. We determined CRABP levels in collagenase-separated dermis and epidermis from 8-day-old embryos using specific binding of all-trans-[11-3H]retinoic acid in cytosols prepared from gram quantities of these tissues. The level of CRABP in dermis was twice the level in epidermis whether calculated on the basis of wet weight, cytosol protein, or DNA. When averaged over many preparations, 3 times as much dermis as epidermis was recovered from a single piece of skin. Therefore, the dermis contained 85% of the extremely high CRABP levels found in collagenase-treated skin, while epidermis contributed only 15%. Cytoplasmic retinol binding protein (CRBP) was also detected in chick embryo skin, but the binding was low and the levels in epidermis and dermis were not significantly different. The amount of CRABP in chick embryo skin (1600 pmol/g wet weight or 100 pmol/mg cytosol protein) is the highest level reported in any tissue and suggests an important role for vitamin A in the normal development and maturation of skin.

Animals↗

PubMed1985

Formation of cadaverine as an effect of alpha-difluoromethylornithine on chick embryo fibroblasts transformed by rous sarcoma virus.

Chick embryo fibroblasts grew normally in the presence of 1 X 10(-3) to 10 X 10(-3) M alpha-difluoromethylornithine (DFMO). This drug did not interfere with protein and DNA synthesis of normal fibroblasts and of cells transformed by Rous sarcoma virus. The morphological appearance of normal and transformed cells was not altered by DFMO, as determined by scanning electron microscopy. Flow microfluorometric analyses also confirmed the notion that normal or transformed cells were not blocked by DFMO in the G1 phase of the cell cycle. As expected, DFMO reduced cellular putrescine levels. This diamine, however, was replaced by the analogue cadaverine (1,5-diaminopentane), which accumulated mainly in the transformed cells. The increase in cellular cadaverine levels was also demonstrated during the infection of chick embryo fibroblasts with a temperature-sensitive mutant of Rous sarcoma virus under permissive conditions. Under restrictive conditions (42 degrees C), less cadaverine accumulated in the infected cells. These findings suggest that diamines and polyamines are necessary for the transformation process and that blocking one pathway by DFMO leads to the activation of an alternative biosynthetic pathway.

Animals↗

PubMed1978

Development of Leucocytozoon caulleryi in chick embryos infected by biting of Culicoides arakawae through shell membrane.

Chick embryos were infected with Leucocytozoon caulleryi by biting of the midge, Culicoides arakawae, through the shell membrane. Schizonts of L. caulleryi were detected in the chorioallantoic membrane and most of the internal organs of embryos and of chicks after hatching. The development of schizonts was slower in embryos than in chickens. Soluble antigens of L. caulleryi were demonstrated by the precipitation test in the allantoic fluid and blood from the embryos and chicks. No erythrocytic stage of L. caulleryi, however, was observed in any embryo or chick.

Animals↗

PubMed1997

Afferent portal venous system in the mesonephros and metanephros of chick embryos: development and degeneration.

BACKGROUND: In the chick embryo, both mesonephros and metanephros have a renal portal system. The classical literature gives uncertain answers about the development and degeneration of the meso- and metanephric portal venous system. Some mesonephric vessels present angiogenic processes to colonize the metanephros, while others show signs of degeneration and disappear together with the mesonephros. The adult avian kidney has a conspicuously placed valve, the renal portal valve. The development of this functionally important renal portal valve has not yet been studied in detail. METHODS: Scanning electron microscopy of vascular corrosion casts has been used in this study. Strong mesonephric degeneration as well as metanephric growth and maturation occur in the developmental stages selected for this investigation (7.5, 9, 11, 14, and 21 days of incubation). RESULTS: The mesonephric afferent venous system in the chick embryo is supplied by two vessels, the posterior and the anterior mesonephric portal veins. The posterior mesonephric portal veins show a similar pattern to the anuran (amphibian) kidney. The anterior mesonephric portal vein has not previously been described. Constrictions were found in this vessel, a probable sign of subsequent degeneration. The metanephric afferent venous system is also supplied by two vessels: the caudal and cranial metanephric portal veins. The caudal metanephric portal vein is derived from the postcardinal vein. The cranial metanephric portal vein grows independently throughout the development of the mesonephric vascular system. It is connected to the vertebral venous sinus already at the beginning of its development. The renal portal valve first appears as a capillary network that communicates with the developing afferent and efferent metanephric venous systems. This capillary network later develops to a venous valve. The metanephric afferent venous system shows typical angiogenic signs in corrosion cast, such as nodular protrusions, holes, and enlarged vessels. CONCLUSIONS: The postcardinal vein first supplies only the mesonephric tissue as a portal vessel. Then it becomes a common source for both kidney generations. Finally it supplies only the metanephric tissue with venous blood. However, two independent vessels were found to supply the cranial renal regions: the anterior mesonephric portal vein and the cranial metanephric portal vein.

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PubMed1996

A light and electron microscopic radioautographic study on RNA synthesis in the retina of chick embryo.

The incorporation of 3H-uridine into RNA of chick embryo retina was studied by light and electron microscopic radioautography. The numbers of silver grains were counted over the nucleus, nucleolus and cytoplasm of the cells in three different regions of the same retina of 2, 3, 4, and 7 day chick embryos. The results showed an increase of 3H-uridine incorporation from embryonic day 2 to 7. In every stage of development of the chick embryo retina, the number of silver grains was higher in the anterior than in the other two regions of the retina. In the three cell compartments of every embryo group, the number of silver grains was higher in the nucleus than in the nucleolus and cytoplasm. The results show further that the grains were less in the cytoplasm of the retinal cells of the day 2 embryo group and higher in the other groups especially in the day 7 embryos. Ultrastructural changes were also observed during the studied period of retina development.

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PubMed2001

Introduction of DT40 cells into chick embryos.

AIM: To examine the transfection of exogenous genes into chick embryos, applying the characteristics of avian leukosis virus (ALV)-induced chicken B cell line DT40 to the production of chimeric birds. METHODS: The DT40 cells incorporated with exogenous gene ( lacZ constructs encoding Escherichia coli beta-galactosidase: beta-gal) were introduced into chick embryos by the injection of cells into stage X blastoderm. Manipulated eggs were incubated for 3 (trial 1) or 6 (trial 2) days, and the expression of lacZ DNA was detected by a histochemical staining method of beta-galactosidase and polymerase chain reaction (PCR) analysis. RESULTS: The survival rates of the manipulated embryos incubated for 3 days (stage 18-20: trial 1) and 6 days (stage 28, 30: trial 2) were about 42% and 38%, respectively. The expression rates of the lacZ gene in the embryos in the trials 1 and 2 were about 60% and 23%, respectively, for the survived embryos. CONCLUSION: The rate of embryonic viability and expression rate of introduced genes were not so high, but it suggested the possibility of utilizing the DT40 cells as a vector for carrying exogenous genes into chick embryos.

Animals↗

PubMed1987

Chloroquine is a muscarinic antagonist. Binding and dose-response studies with chick embryo cells.

A muscarinic acetylcholine receptor is present on undifferentiated cells of the chick embryo. We show that, in the chick embryo, chloroquine binds to the muscarinic receptor site and behaves as a muscarinic antagonist. In competition studies performed with cell suspensions, chloroquine displaced the specific muscarinic ligand [3H]quinuclidinylbenzilate ([3H]QNB) from the receptor. The dissociation constant (KD) of chloroquine was calculated to be 6.0 X 10(-6) M. In saturation studies performed in chick embryo homogenate, chloroquine shifted the binding curve of [3H]QNB to the right (KD = 4.8 X 10(-6) M). Dose-response curves were established by measuring the acetylcholine-triggered Ca2+ mobilization in cell suspensions by means of a fluorometric assay with chlorotetracycline. Chloroquine shifted the dose-response curve to the right. The inhibitory constant (KI) of chloroquine calculated from the dose-response curve was 1.5 X 1 10(-5) M. Our observations provide an explanation for the known interference of chloroquine with the muscarinic cholinergic systems in a variety of adult organs.

Animals↗

PubMed1988

Pretreatment of chick embryos with estrogen in ovo prevents mullerian duct regression in organ culture.

Diethylstilbestrol (DES) feminizes chick embryos in ovo, preventing regression of the Mullerian ducts (MDs). The feminized testis, however, despite its ovarian-like appearance, continues to produce Mullerian inhibiting substance (MIS). This study was designed to test whether exogenous DES preserved the MD against endogenous MIS by affecting the target organ (feminization). DES (0.1 mg) was injected into the air sacs of 5-day-old chick embryos. Testes were obtained from 15-day-old chick embryos and MDs from 8-day-old chick embryos and combined in organ culture for 72 h. MD regression was examined macroscopically and microscopically after 3 days in vitro in medium without DES (group A: n = 155) and with 10(-6) M DES (group B: n = 169). Four types of coculture were set up as follows: 1) Control testis with control MD; 2) DES-treated testis with DES-treated MD; 3) Control testis with DES-treated MD; 4) DES-treated testis with control MD. In medium without DES (group A), MD regression was inhibited significantly when the duct was pretreated with DES [2) and 3) vs. 1) and 4)]. The pretreated testis produced slightly less regression [4) vs. 1)], but this was not significant. Previous studies in ovo had suggested that estrogen prevented MD regression directly as well as causing feminization of the testis, because MIS secretion was not inhibited from the feminized gonad. These results show that pretreatment of the MD with DES blocks regression in vitro by a normal testis, confirming that the primary site of action of estrogen is on the duct itself.

Animals↗

PubMed1991

Concomitant changes in endothelial cell junctions and extracellular matrix components in the chick embryo aorta.

According to previous studies, a process of endothelial activation seems to be occurring in the chick embryo between days 7 and 18. Also, endothelial cells respond to collagen as a substratum between 12 and 18 days, and this response diminishes until it almost disappears after birth. In the present study, aortas from chick embryos (days 7 to 21), and from chicks (14 days posthatching) were used. The results obtained by the freeze-fracturing technique, showed that between days 12 and 14 the intramembranous particles were aggregated into linear or clustered arrays in the fracture P-face of endothelial cells. This could signify that some kind of gap junction-like coupling may occur between adjacent endothelial cells. Our results also indicate that in advanced stages (21-day-old chick embryos and 14-day-old chicks) the growth of small aggregates into larger aggregates or plaques could occur. In addition to gap junctions, the presence of macular and linear tight junctions, reported as focal tight junctions (day 14 of development) macular and linear tight junctions with free-ending strands oriented parallel to one another (21 days) and smooth contoured ridges (14 days post-hatching) were observed. This sequence of changes may represent a development from linear to macular, to a more occluding arrangement, and may also reflect an endothelial cell polarization. Histochemical study of proteoglycans was done by using cuprolinic blue according to the critical electrolyte concentration method. Cuprolinic blue-positive granular, elongated and microfibrillar materials were found in the subendothelial region, forming a meshwork that occupies the extracellular space. Qualitative and quantitative changes were observed both in proteoglycans and in other extracellular matrix components throughout development, suggesting an increase in extracellular matrix complexity. These results lead us to suggest that the assembly of a more complex extracellular matrix, concomitantly with the formation of intercellular junctions during development, might influence the polarization of endothelium in the aorta of the chick embryo.

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PubMed1980

Hemopoietic colonies on the chorioallantoic membrane of the chick embryo: induction by embryonic, adherent, non-hemopoietic spleen cells.

Granulocytic and erythrocytic colonies developed on the chick embryo chorioallantoic membrane (CAM) following the inoculation of chick embryo spleen cells. Dose response and kinetic experiments showed that the colonies were derived from cell aggregates present in the inoculum. Dissociation and reaggregation studies of the CAM colony-inducing cells (CAM-CIC) indicated that these cells must be present as aggregates in order to form colonies. Results from the morphology and cell marker experiments suggested that the colony-inducing aggregates (CAM-CIA) attract and support the differentiation of primitive host hemopoietic cells. The physical characteristics of the CAM-CIC, which are different from those of the hemopoietic progenitor cells, indicated that they represent a stromal cell population of the chick embryo spleen. Further evidence supporting this notion was provided by the radiation studies which showed that the colony-inducing ability of the CAM-CIC is radioresistant. The above characteristics of the CAM-CIC strongly suggest that they represent the stromal cells of the chick embryo spleen which influence hemopoiesis.

Allantois↗

PubMed1977

Morphologies of cells from 1-day chick embryos.

Cells disaggregatedfrom 1-day chick embryos show three morphologies,two reminiscent of mammalian erythrocytes and one epithelial. The presence of intermediate forms suggests that the three morphologies are interconvertible.

Age Factors↗

PubMed1996

Serum sensitivity and apathogenicity for chickens and chick embryos of Escherichia coli J5 strain.

Escherichia coli J5 strain was assessed for its serum resistance and pathogenicity for both chickens and chick embryos. Pathogenicity for chickens was assessed by intravenous inoculation into three-week-old broiler chickens. Pathogenicity for chick embryos was determined by inoculation of 12-day-old chick embryos into the allantoic cavity. Chicken serum was used to determine the serum resistance status. E coli J5 strain was found to be serum-sensitive and apathogenic for chickens and chick embryos. No mortality and no gross lesions occurred in the chickens inoculated with this strain. The chick embryos inoculated with this strain remained alive. It is worth trying this strain as a live vaccine to immunize chickens against infection from different serotypes of E coli.

Allantois↗

PubMed1995

Effect of chronic ethanol on phospholipase A2- and C-activity in chick embryo brain, heart and liver.

The activities of phospholipase A2 (PLA2) and C (PLC) in subcellulal fractions from chick embryo brain, heart and liver were determined using the substrate 1-palmitoy 1-2-N-(4-nitrobenzo-2-oxa-1, 3-diazole amino caproyl-phsphatidylcholine (NBD-PC), and the effect of chronic ethanol treatment on these activities was evaluated. PLA2 and PLC activities of each fraction were assayed by measuring release of N- (4-nitrobenzo-2-oxa-1, 3-diazole) amino caproic acid (NBD-caproic acid) and of 1-palmitoy 1-2-NBD amino caproyl glycerol (NBD-DG) from exogenous NBD-PC. The microsomal membrane fluidity was estimated from diphenylhexatriene anisotropy (gamma). Cytosolic, mitochondorial, and microsomal subcellular fractions were prepared by differential centrifugation of homogenates of the brain, heart, and liver. Microsomal subcellular fractions from the brain, heart and liver of ethanol treated chick embryo showed significantly higher PLA2 and PLC specific activities than did corresponding fractions from non-treated chick embryo. Mitochondrial subcellular fractions from the brain and heart of ethanol-treated chick embryo also showed significantly higher PLA2 and PLC specific activities than the corresponding control fractions. Microsomal fractions from the brain and heart of ethanol-treated chick embryo decreased significantly the gamma than those of control. These results suggest that the change in the membrane fluidity is an apparent prerequisite for the changes of PLA2 and PLC activities.

Animals↗

PubMed1998

Coumarin chemoprotection against aflatoxin B1-induced gene mutation in a mammalian cell system: a species difference in mutagen activation and protection with chick embryo and rat liver S9.

Coumarin (1,2-benzopyrone), a natural food constituent, prevents polycyclic aromatic hydrocarbon-induced neoplasms in rats and mice, but has not been studied with other chemical carcinogens. We examined coumarin chemoprotection against aflatoxin B1 using the 6-thioguanine resistance mutation assay in two different Chinese hamster ovary cell lines (K1BH4 and AS52) with liver S9 from rats and 19-day-old chick embryos for aflatoxin B1 bioactivation. Laboratory rodents metabolize coumarin through 3-hydroxylation, whereas 7-hydroxylation predominates in chick embryos and humans. Chick embryo liver S9 was approximately 25-fold more effective in activating aflatoxin B1 to the mutagenic and cytotoxic metabolite(s) than rat liver S9. Coumarin added at 50 and 500 microM with chick embryo liver S9 reduced the mutant frequency of 1 microM aflatoxin B1 by 40 and 85%, respectively. Coumarin up to 500 microM had no effect on aflatoxin B1 mutagenicity with rat liver S9. When liver S9 from chick embryos pretreated with coumarin was used for aflatoxin B1 bioactivation, mutant frequency and cytotoxicity were decreased compared to liver S9 from vehicle-treated controls. Liver S9 from coumarin-treated rats did not significantly affect mutant frequency or cytotoxicity. HPLC analysis of chick embryo liver S9 incubated with 1 microM aflatoxin B1 showed a dose-dependent decrease by coumarin of aflatoxin B1 activation to the 8,9-epoxide ranging from 70% of controls at 5 microM coumarin to 4% of controls at 500 microM coumarin. In contrast, coumarin produced a dose-dependent increase in 20 microM aflatoxin B1 activation by rat liver S9, reaching twice the control levels at 500 microM coumarin. These findings, using a mammalian cell system as a mutagenic endpoint, demonstrate marked species differences in chemoprotection by coumarin.

Aflatoxin B1↗

PubMed1976

Developmental changes in prolyl hydroxylase activity and protein in chick embryo.

Changes in prolyl hydroxylase activity and immunoreactive protein were studied in various chick embryo tissues during the embryonic development. Both the enzyme activity and the amoung of immunoreactive protein increased till the 16th day of development and declined thereafter in all tissues studied. Comparison of the enzyme activity to the content of the total immuno-reactive protein indicated that there are distinct differences in the degree of enzyme activity between different chick embryo tissues, and in the same tissue between different stages of embryonic development. The highest relative enzyme activities were found in cartilage and skin, in which about 60% of the enzyme was active on the 16th day of development and only 20-30% was active on the 20th day of development; the lowest values were observed in spleen and large vessels, in which below 10% of the enzyme protein was in the active form on the 20th day of development Gel filtration studies demonstrated that in cartilage of 16-day-old chick embryos about 60% of the total immunoreactive enzyme in the tissue was present in the form of active prolylhydroxylase tetramer, whereas on the 20th day of development only 30% of the enzyme protein in cartilage was in the tetramer form. By contrast, in large vessels of the 16-day-old chick embryos, essentially all the enzyme was in the form of prolyl hydroxylase monomers.

Animals↗

PubMed1987

Carrageenan induces anomalies in the chick embryo. A light microscopic study.

Chick embryos injected with lambda-carrageenan prior to incubation and studied with light microscopy at 48 hours of development presented various anomalies. Lack of closure at different levels of the neural tube was one of the lesions most frequently seen. Rachischisis and craniorachischisis were commonly associated with various degrees of hyperplasia of the neural tube wall. Diverse patterns of neural hyperplasia ranged from total occlusion of the neural tube to localized thickening of lateral walls leading to a typical "hourglass" appearance of the ependymal lumen. Multiple septa and cavitations of the neural tube lumen were also recorded. Cephalic and/or trunk duplication of the body as well as disorganization of notochord and somites were frequently associated with rachischisis and areas of necrosis or pyknosis of neural tissue. Neural crest cells, which are normally present in paraneural areas at the stages studied, were not encountered in the carrageenan-injected embryos. These areas were frequently occupied by hyperplastic ectodermic folds. Similarity of present findings on carrageenan-treated embryos with the anomalies induced by selective destruction or impairment of migration of neural crest cells suggests that involvement of this cell population may have a role in the causation of the anomalies observed.

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PubMedDate not supplied

"In vitro" expression of the cardiogenic potentiality of chick embryo heart-forming cells.

Chick embryos between final presomitic and 4 somites stage were studied. The subcephalic fold was handly severed from the embryos and cultivated in liquid medium for 7 days. Because of the embryo age, no heart anlage was observed at the moment of dissection. After 4 hours of culture the cells began to migrate from the explants. After 20 hours a very extended migration ring was observed in all of the cultures; in the explants, one or more newformed tubular or spherical masses of cells throbbed rhythmically. Their size and shape were related to the embryos age: from presomitic embryos, irregular clusters appeared, while starting from two somites embryos tubular, vascular-like structures were formed. The cells of the throbbing areas at submicroscopic observation showed organizing myofibrillar apparatus into the cytoplasm; junctional complexes between the cells and gap junctions in course of organization were present in the vascular-like structures. This suggests that very early, in the lateral mesoderm are the presumptive cardiac cells which can develop "in vitro" as myocardic elements even in absence of the interactions that occur during the development "in vitro"; the observed vascular-like structures may be considered as an attempt to form a sort of cardiac primordium "in vitro", and a further step in the expression of the cardiogenic potentiality, involving cell-cell communications. The serial sections of the embryos enhanced that into the cultivated areas, vessels from yolk sac are always present; this suggests that the vascular structures, i.e. the endothelium may be involved in the determination of the myocardic elements.

Animals↗