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PubMed1981

Deacylation and reacylation of phosphatidylcholines by liver homogenates from chick embryos.

Liver homogenates from 13, 17 and 21 day-old chick embryos were incubated with phosphatidylcholine and lysophosphatidylcholine labeled with fatty acids to study deacylation and reacylation reactions of phosphatidylcholines during development. By using phosphatidylcholines labeled with palmitic or linoleic acids in position 1 or 2, respectively, phospholipase A2 activity was detected. By using lysophosphatidylcholine labeled with palmitic acid in position 1, preferential acylation with araquidonic acid was demonstrated. In agreement with this data, the incubation of dienoic phosphatidylcholines labeled with palmitic acid in position 1, with the liver homogenates, gave rise to labeled tetraenoic phosphatidylcholines. The extent of both deacylation and reacylation of the phosphatidylcholine molecule in position 2 by liver homogenates from chick embryos, decreased during development.

Acylation↗
PubMed1990

In vitro effects of gonadotrophic and steroid hormones on the interstitial cells of the chick embryo ovaries.

The embryonic gonads produce and secrete the steroid hormones that induce secondary sex differentiation in different species. The production of estrogens, testosterone and progesterone by interstitial cells of the chick embryo ovary has been demonstrated in experiments in ovo and in vitro. Estrogens would be responsible at the 7th day of in ovo incubation, of the evolution of the functional left ovary. According to Gasc, only the cells of the germinative epithelium of the left ovary possess receptors for estrogens, thus originating the formation of a cortex in this functional gonad and not in the right one. On the other hand, extragonadal factors, such as gonadotrophins, would participate in gonadal differentiation. Involvement of the hypophysis in the morphological and functional differentiation of the ovary in the chick embryo, has been considered in several studies. Woods and Week established the functional hypophysealgonadal axis at 13 days of in ovo incubation. However, the effects of individual gonadotrophins on the interstitial cells of the chick embryo remain unclear. Avila et al. and Grassi Milano observed that when the female gonads were cultured without steroid or gonadotrophic hormones at the start of differentiation an hermaphrodite left ovary and a male right one were formed. Kyparissi and Vakolopoulu observed that the inoculation in ovo of FSH at the end of embryonic development led to an increment in the number and size of follicles in the left ovary. Pittini and Grassi Milano added FSH and LH to cultures of 15 days-old chick embryos testicles and ovaries and found that only male gonads developed similar to normal embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The patterns on chondrogenesis of cells from facial primordia of chick embryos in micromass culture.

Chondrogenesis of mesenchymal cells from the frontonasal mass, mandibles and maxillae of stage-24 chick embryos has been investigated in micromass (high-density) cultures. Distinct differences in the amount and pattern of cartilage differentiation are found. In cultures of frontonasal mass cells, a central sheet of cartilage develops; in cultures of mandible cells, less cartilage differentiates and nodules form; while in cultures of maxillae cells, virtually no chondrogenesis takes place. The same patterns of cartilage are found in cultures established from stage-20 embryos. At stage 28, frontonasal mass cultures form cartilage nodules and the number of nodules in mandible cultures is markedly decreased. There are striking parallels between the chondrogenic patterns of cells from the face and limb buds in micromass culture. The frontonasal mass cell cultures of stage-20 and -24 chick embryos resemble those established from the progress zone of limb buds. The progress zone is an undifferentiated region of the limb in which positional cues operate. Cultures established from the frontonasal mass of stage-28 chick embryos and from the mandibles of all stages resemble cultures of whole limb buds. These contain a mixture of committed and uncommitted cells. Ectoderm from facial primordia locally inhibits chondrogenesis in micromass cultures and this could provide a positional cue. The differences in chondrogenic potential of cells from facial primordia may underlie the specific retinoid effects on the frontonasal mass.

Age Factors↗
PubMed2005

Bilateral neuro-retinitis following chick embryo cell anti-rabies vaccination--a case report.

BACKGROUND: The Optic nerve is rarely involved after sheep brain anti-rabies vaccination in the form of retrobulbar neuritis or papillitis. Bilateral neuroretinitis after chick embryo cell antirabies vaccination has not been reported. CASE PRESENTATION: We report the case of a 56 year old male who developed bilateral neuro-retinitis following three injections of antirabies vaccine prepared from the chick embryo. CONCLUSION: The chick embryo cell antirabies vaccine can cause bilateral neuroretinits which has not been reported previously.

Animals↗
PubMed1984

Expression of cone-like properties by chick embryo neural retina cells in glial-free monolayer cultures.

We report here that cells present in embryonic chick retinal monolayer cultures express differentiated properties characteristic of chick cones developing in vivo. Cell suspensions from 8-d chick embryo retina (a stage when photoreceptor differentiation has not yet started) were cultured for up to 7 d in low density, glial-free monolayers. Under these conditions, monopolar cells represent approximately 40% of the total number of process-bearing neurons. After 6 d in vitro, most of these monopolar cells showed morphological features reminiscent of developing chick cones. These features could be detected with phase-contrast microscopy, lectin cytochemistry, and transmission and scanning electron microscopy. Characteristic cone traits expressed by cultured monopolar cells included the following: (a) a highly polarized organization; (b) a single, short, usually unbranched neurite; (c) the polarized position of the nucleus close to the origin of the neurite; (d) characteristic cone inner segment features such as abundant free ribosomes, a polarized Golgi apparatus, a cluster of mitochondria distal to the nucleus, a big, membrane-bound, pigment-containing vacuole reminiscent of the "lipid droplet" characteristic of chick cones, and at least in some cases, a well-developed paraboloid; (e) the presence of a complex of apical differentiations including abundant microvilli and in some cases also a cilium-like process; and (f) the staining of the apical region of the cell with peanut lectin, which has been shown to be selective for chick embryo cones (Blanks, J.C., and L.V. Johnson, 1983, J. Comp. Neurol., 221:31-41; and Blanks, J.C., and L.V. Johnson, 1984, Invest. Ophthalmol. Visual Sci., 25:546-557). This pattern of differentiation achieved by 8-d chick retina cells after 6 d in vitro is similar to that shown by 14-d-old chick embryo cones in vivo. Outer segments are not present at this stage of development either in vivo or in vitro. This experimental system is now being used to search for cellular and molecular signals controlling survival and differentiation of cone cells.

Animals↗
PubMed1979

Studies of the effect of chloramphenicol, ethidium bromide and camptothecin on the reproduction of Rous sarcoma virus in infected chick embryo cells.

A function for mitochondria in the reproduction of Rous sarcoma virus (RSV) in chronically and newly infected chick embryo cells was studied by using chloramphenicol and ethidium bromide. Chloramphenicol (CAM) and ethidium bromide (EB) were both shown to decrease the rate of growth of infected chick embryo cells and to inhibit the synthesis of mitochondrial macromolecules. Both drugs however had little or no effect on the incorporation of labelled leucine, thymidine and uridine into total cellular macromolecules. Neither CAM (80 microgram/ml) nor EB (0.4 microgram/ml) inhibited the production of infectious virus. In contrast, camptothecin, an inhibitor of cellular but not mitochondrial macromolecular synthesis, was shown to depress the production of infectious virus. The results indicate that the mitochondrial macromolecular synthesis machinery of RSV-infected chick embryo cells does not contribute to virus production.

Animals↗
PubMed1990

On the development of the chick embryo colon: a computerized morphometric study.

The quantitative aspects of the chick embryo colon organogenesis (proximal and distal tracts) have been studied from the 7th to the 15th day of incubation on histological sections by means of a computerized morphometric system. A semiautomatic digital system (Videoplan 2) was used. The area of total section, of the lumen, of the wall and its components (subserous stratum, muscle layer, lamina propria, epithelium) and the thickness of the epithelium and muscle layer were measured; the mean +/- S.E.M. of the obtained values was calculated. The percentage of shrinkage, due to histological procedures, was calculated for each day. The mean values for each day of incubation were modified on the basis of the shrinkage percentage. The differences between the mean values of the areas of the proximal and distal tract were statistically evaluated. Exponential curves and r coefficient were determined to evaluate the general growing pattern of the mean area of colonic wall components as a function of age. The main results demonstrate that in both tracts the component with the greatest growth was the muscle layer, while there are some differences between the proximal and distal tracts of the colonic anlage in the growing pattern of other wall components. The colonic anlage also shows a different developmental behaviour compared with that of the chick embryo ileum and duodenum.

Animals↗
PubMed1985

Effects of insulin-like growth factors on chick embryo hepatocytes.

Biological effects of insulin-like growth factors (IGF) I and II on primary cultures of chick embryo liver cells have been investigated and compared 1) with the biological effect of insulin and 2) with competitive binding of the three hormones to their respective binding sites. IGF I and II stimulate the incorporation of D[U-14C]-glucose into liver cell glycogen in a time- and dose-dependent manner, but with a 5-10-fold lower potency than insulin. Both IGFs also lead to enhanced incorporation of 5-[3H]uridine and L[U-14C]valine into trichloroacetic acid (TCA) insoluble material and to activation of ornithine decarboxylase activity. Their potency in stimulating RNA synthesis and ornithine decarboxylase activity is comparable to that of insulin. Protein synthesis is maximally stimulated at 3 nM by all three hormones. In the competitive binding studies, IGF I and II are 10-fold less potent than insulin in competing for [125I]insulin binding, but 100-fold more potent than insulin in competing for [125I]IGF I or II binding. These studies show that IGF I and II stimulate the same metabolic indices as insulin in the chick embryo liver. By comparing these biological effects with competitive binding data it appears that IGFs act on glucose metabolism in the chick embryo liver via the insulin receptor, whereas stimulation of growth indices by IGFs and insulin appears to be mediated by their own specific receptors.

Animals↗
PubMed1977

Effect of cortisol acetate on collagen biosynthesis and on the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase in chick-embryo tendon cells.

Collagen synthesis and the activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase were studied in isolated chick-embryo tendon cells after the administration of cortisol acetate to the chick embryos. When the steroid was injected 1 day before isolation of the tendon cells, collagen synthesis was decreased, even though the enzyme activities were not changed. When cortisol acetate was given as repeated injections over a period of 4 days, both collagen synthesis and the enzyme activities decreased. The hydroxylase activities decreased even more than the two collagen glycosyltransferase activities, both in isolated cells and in whole chick embryos. The amount of prolyl hydroxylase protein diminished to the same extent as the enzyme activity, indicating that cortisol acetate inhibits enzyme synthesis. The inhibitory effect of cortisol acetate on collagen synthesis and on the enzyme activities was partially reversible in 3 days. Total protein synthesis was completely restored within this time. Only massive doses of cortisol acetate inhibited collagen synthesis in vitro. Additional experiments indicated that cortisol acetate did not decrease the rate of the enzyme reactions when added directly to the enzyme incubation mixtures. The results suggest that cortisol acetate decreases collagen synthesis both by its direct effect on collagen polypeptide-chain synthesis and by decreasing the activities of enzymes involved in post-translational modifications.

Animals↗
PubMed1983

The use of early chick embryos in experimental embryology and teratology: improvements in standard procedures.

The chick embryo is a convenient experimental system for embryologic and teratologic studies. However, windowing eggs during the first day of incubation, a procedure that is required to expose embryos in ovo, frequently results in dysmorphogenesis. The frequency and severity of the particular anomalies caused by windowing are greater the younger the embryo at the time this procedure is done. At all stages examined, dysraphic defects of the neural tube are the most common anomaly present following windowing. Defects of the neural tube are virtually eliminated if the air space introduced over the embryo by windowing is filled with albumen or saline, and the egg (with its window sealed with tape) rotated 180 degrees, so that the embryo rests subjacent to an undisturbed area of the shell. Subblastodermic injection of saline, a vehicle often used for teratogenic agents, has no adverse effects when eggs are subsequently filled with albumen or saline and rotated. Furthermore, known teratogens (e.g., colchicine, hyaluronidase) injected subblastodermically after windowing are active in eggs that are then filled with albumen or saline and rotated. Finally, the addition of albumen or saline, followed by rotation, may be delayed up to 3 hours without reducing the restorative effects of these two procedures. Our modified procedures for the handling of windowed eggs significantly increase the value of young chick embryos for studies of early developmental events.

Animals↗
PubMed1984

Effects of follicle-stimulating hormone, luteinizing hormone and prolactin on left and right gonads of female chick embryos in culture.

Organotypic cultures were made of right female gonads of chick embryos of 8 days, on medium containing follicle-stimulating hormone, luteinizing hormone or prolactin (PRL), and of left ovaries of the same age on the medium containing PRL. Results indicate that the explants cultured on PRL resemble most closely the normal ovaries in vivo. It is suggested that PRL may have a function in the morphogenesis of the female gonads of chick embryos.

Animals↗
PubMed1972

Development of chicken lymphoid system. II. Synthesis of primordial immunoglobulin M by the bursa cells of chick embryo.

Development of Ig-synthesizing cells in the bursa of chick embryo was studied by immunohistochemical staining method as well as by in vitro incorporation of leucine-(3)H into Ig. Ig-synthesizing cells are first detected in the bursa of a 14 day old chick embryo and increase with the maturation of the embryo. Acrylamide gel analysis of leucine-(3)H-labeled Ig shows that synthesis of nonsecretory IgM-H(0) precedes that of secretory IgM-H, reflecting an ontogenetic sequence of development of lymphoid cells synthesizing IgM. Since IgM-H(0) is not secreted, we further studied biochemical differences between two heavy chains. The difference is attributable to lack of galactose attachment to H(0) chains. It is proposed that during differentiation of lymphoid cells synthesizing and secreting Ig, attachment of galactose may play an obligatory role in the development of cellular capacity for Ig secretion.

Acrylamides↗
PubMed1992

Inhibition of protein synthesis increases the transcription of the phenobarbital-inducible CYP2H1 and CYP2H2 genes in chick embryo hepatocytes.

The mechanism by which phenobarbital and similar compounds regulate gene expression has remained elusive for many years despite intense investigation. We had previously reported that the mRNA expression for the phenobarbital-inducible CYP2H1 gene was increased by cycloheximide treatment as rapidly and to a similar extent as by the phenobarbital-type drugs glutethimide and 2-propyl-2-isopropylacetamide (PIA), in primary cultures of chick embryo hepatocytes or in chick embryo liver in vivo (J. W. Hamilton, W. J. Bement, P. R. Sinclair, J. F. Sinclair, and K. E. Wetterhahn, 1988, Biochem. J. 255, 267-275). To examine the mechanism of this induction further, we determined the effects of various structurally related and unrelated inhibitors of protein synthesis on CYP2H1 expression in cultured chick embryo hepatocytes. Cycloheximide increased the transcription rate of the CYP2H1/2 genes to a similar extent as did PIA, and had little or no effect on CYP2H1 mRNA half-life. A number of other protein synthesis inhibitors, including streptovitacin, acetoxycycloheximide, pactamycin, and ricin, all increased CYP2H1 mRNA expression to a similar extent. The dose responses for induction of CYP2H1 mRNA and inhibition of protein synthesis by these agents were closely correlated. There was no relationship between the effectiveness of these agents to induce CYP2H1 mRNA expression and their structures or lipophilicity. Cycloheximide acetate required deesterification to cycloheximide for both inhibition of protein synthesis and induction of CYP2H1 mRNA. These results suggest that a labile negative regulatory protein is involved in CYP2H1/2 gene expression. It is also possible that this factor is involved in regulating the phenobarbital response of CYP2H1/2.

Animals↗
PubMed1982

Estrogen inhibition of Mullerian inhibiting substance in the chick embryo.

Diethylstilbestrol (DES) feminizes the embryonic chick testes and causes retention of the Mullerian duct, an observation made by Etienne Wolff in 1939. The present study was designed to determine if the feminized testis could produce Mullerian Inhibiting Substance (MIS). DES in various doses was injected into the air sac or yolk of 5-day chick embryos, with removal of the gonads at 13-16 days of incubation. That the DES-treated testis was feminized was documented by the development of a left "ovarian" cortex, yet this gonad continued to produce MIS as estimated by a graded organ-culture assay. The male chick Mullerian ducts, exposed to both endogenous MIS and exogenous estrogen (DES), however, were preserved, indicating that the Mullerian duct retention seen in DES-treated embryos was not caused by suppression of MIS secretion. These data support the hypothesis that MIS and estrogens interact at the target-organ (i.e., Mullerian duct), resulting in Mullerian duct retention. The implications of this hypothesis for mammalian sexual development especially in regard to the effect of DES-treatment on male fetuses, and the possible role of MIS and estrogens in testicular descent are considered.

Animals↗
PubMed1994

Effect of hydroquinone (HQ) on the development of chick embryos.

The developmental toxic effect of hydroquinone (HQ) was evaluated in chick embryos after 72 and 96 hour of incubation. HQ was injected into the air sacs of the eggs at doses ranging from 0.0625 to 40 micrograms per egg. On the 15th day of incubation, live embryos including controls were removed from the eggs and examined for gross malformations and body hemorrhage. The LD50 values for HQ at 72 and 96 hours of incubation were 8.59 and 15.63 micrograms per egg, respectively. HQ produced gross malformations such as body hemorrhage, curled claws, everted viscera, defective beak, exencephaly and monophtalmia in developing chick embryos at dosages ranging from 20 to 0.0625 micrograms per egg in both groups. The various types of malformations and their incidences in both groups were higher in comparison with the controls, but were not statistically significant. At no concentration did malformations occur greater, than 35 percent for both 72 and 96 hours of incubation. The results of this study reveal that HQ is embryo toxic at higher doses and that teratogenic potential of HQ is unremarkable.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

[The action of cisplatin on the developing meso- and metanephros of chick embryos].

Injection of various doses of cisplatin to 2-14-day chick embryos showed that within 2-8 days of incubation cisplatin produces total toxic effect, the number of dead embryos being dependent on a dose of the drug. Within 9-16 days of incubation, i.e. a period when both the mature mesonephros and the developing metanephros are in action, no significant changes were observed in the content of urea and uric acid, the weight of the meso- and metanephros, their water content, and ion content of the blood. Electron microscopic studies revealed no structural changes in the renal tubules. The data obtained suggest that cisplatin does not produce any nephrotoxic effect in chick embryos irrespectively of their age.

Animals↗
PubMed1970

Overgrowth-stimulating activity of disrupted chick embryo cells and cells infected with Rous sarcoma virus.

Sonically disrupted chick embryo cells markedly stimulate DNA synthesis and cell multiplication when added to the medium of population density-inhibited cultures of such cells, but have little effect on the growth rate of sparse cultures. Sonicates from density-inhibited chick embryo cultures have as much overgrowth-stimulating activity as do sonicates from actively growing cells. Sonicates from cells infected with Rous sarcoma virus show markedly increased overgrowth-stimulating activity 4 days after infection. The activity in Rous-cell sonicates falls back to near normal amounts at 6 days concurrently with the appearance of a high content of overgrowth-stimulating activity in the medium. The active material is nondialyzable. It seems that growth-inhibited cells contain material in a sequestered location which, when released, can stimulate rapid growth in similarly inhibited cells.

Animals↗