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PubMed2002

[Subcellular aspects of interstitial cell innervation in chick embryo ovary cultured with LH or hCG].

UNLABELLED: Several authors have shown the effect of LH or hCG gonadotrophins on steroid secretion in the chick embryo ovary. However, the effects of luteinising hormone or human chorionic gonadotropin on chick embryo ovary innervation have not been studied. The purpose of the present work was to study the subcellular aspects of interstitial cells innervation in chick embryo ovaries cultured with LH or hCG. Coob's White Rock female chick embryos at 7, 11, 15 and 19 days of incubation (in ovo) were employed. Explants of the left and right ovaries were cultured separately for 4 days in: 1--Basic medium (control): minimum essential medium (MEM-GIBCO) with 10% bovine fetal serum, 2--Basic medium with added LH or hCG (problems). The cultures were processed to be studied ultrastructurally (TEM). Left and right ovary explants were fixed two hours at room temperature in Karnovsky's fixative. The tissues were then post-fixed in osmium tetroxide in 0.1 M cacodylate buffer for one hour and after a rinse in buffer were dehydrated in acetone: afterwards they were embedded in Araldite resin. Thick sections stained with 1% Toluidine blue were examined and photographed using a Zeiss Photo II microscope. Thin sections were stained with uranyl acetate and lead citrate and examined in a Siemens ElmisKop 101 electron microscope. CONTROLS: In both ovaries the isolated interstitial cells and the appearance of nerve fibers and nerve endings were observed in the explants of 11 day cultured during four days and in a similar way at the age of 15 days of in ovo development. PROBLEMS: With LH or hCG nerve fibers and nerve endings were observed both in the right gonad and in the medulla of the left ovary in close contact with the steroid-producing interstitial cells. Ultrastructurally, the interstitial cells are recognized by their typical organoids: SER, Golgi apparatus, mitochondria with tubular crests and abundant lipidic droplets. The innervation of these cells were seen in ovaries at 7 days development, cultured during 4 days. The present state corresponds to that of 11 days development in ovo. The nerve endings had mitochondria, microtubules and small and medium-sized vesicles, some with an electrodense content. These results in vitro suggest that innervation of the ovaries is controlled by an indirect mechanism via the hypothalamic-pituitary system and another local with production neurotrophic factors modulated by LH.

Animals↗
PubMed1996

Nitric oxide and spontaneous motility in chick embryos.

The effects of direct donors of the nitric oxide molecule on spontaneous motility and its development was investigated in chick embryos. The study was carried out in embryos of white Leghorns from the day 4 to day 19 of incubation. Following direct donors of NO were used: sodium nitroprusside (SNP), hydroxylamine, 1-nitrosopyrrolidine and L-arginine, the natural precursor for enzymatic production of nitric oxide. 1. SNP evoked apparent depression of spontaneous motility as at acute application (20 mg/kg e.w.), as at long-lasting continual supply (1.55 +/- 0.25 mg/kg e.w./24 h) from e.d. 4 to e.d. 8, 12 or 16). The same depressive effect was noted both in normal and spinal embryos. The application of K4Fe(CN)6 pointed out noticeable participation of the cyanide component and perhaps Fe2+ on the SNP effects, too. 2. Hydroxylamine (12.5 mg/kg e.w.) and 1-nitrosopyrrolidine (90 and 900 mg/kg e.w.) evoked a significant activation of spontaneous motility in chick embryos 3. L-arginine (20 mg/kg e.w.) activated spontaneous motility from day 11 of incubation. 4. 1-nitrosopyrrolidine changed not only the resting spontaneous motility in 17-day-old chick embryos, but it changed also the reactivity of the central generator of motility to some neuropharmacological drugs: it potentiated the activatory effect of NMDA, fully abolished the inhibitory effect of ketamine, was suppressed by inhibitory effect of Mg2+ and its activatory effect was significantly reduced by the inhibitory effects of glycine and GABA. 5. These results did not exclude the possible participation of NO-ergic components in the onset of embryonic spontaneous motility and in the NMDA-ergic activation of the central generator of motor behaviour in chick embryos.

Animals↗
PubMed1984

Repair of chromate-induced DNA damage in chick embryo hepatocytes.

The repair of DNA damage caused by chromate was examined in chick embryo hepatocytes. Treatment of chick embryo hepatocytes with 5 microM sodium chromate for 2 h caused the formation of DNA strand breaks, DNA interstrand cross-links, and DNA-protein cross-links. The maximal level of strand breaks and DNA interstrand cross-links was observed immediately after the 2 h chromate treatment. After removal of the chromate, strand breaks and DNA interstrand cross-links were completely repaired by 3 h and 12 h, respectively. In contrast, DNA-protein cross-links continued to form reaching a maximal level 3 h after chromate removal. Although the level of DNA-protein cross-links decreased at later times, a significant level persisted 40 h after chromate removal. The effect of these persistent DNA-protein cross-links on gene expression was examined by measuring induction of porphyrin accumulation by propylisopropylacetamide and deferoxamine methanesulphonate, a process known to depend on mRNA synthesis. Induction of porphyrin accumulation was decreased immediately following the 2 h chromate treatment. Only partial recovery of induction was observed even 40 h after chromate removal. The effect of chromate treatment on cellular glutathione levels was monitored. No change in cellular glutathione was observed after a 2 h treatment with 5 microM sodium chromate; however, a three-fold increase was observed 12 h after removal of chromate.

Animals↗
PubMed1983

Metabolism of 4-hydroxyaminoquinoline-1-oxide and its binding to DNA in chick embryos.

The metabolic pathway of 4-hydroxyaminoquinoline-1-oxide (4HAQO) and its binding to DNA was studied in 2-day chick embryos administered [G-3H]4HAQO in a shell-less culture. The 4HAQO rapidly metabolized into non-carcinogenic compounds and 1 h after administration only very small amounts of free 4HAQO could be detected in the embryo cells. The amount of DNA-bound 4HAQO in the embryo cells reached a maximum 2 h after administration, then began to decrease. The maximum extent (mu mol/mol P of nucleotide) was 18.2, equivalent to 1 molecule of 4HAQO-purine adducts per 2.8 X 10(4) base pairs of DNA. It was possible to detect removal of 4HAQO-purine adducts from DNA in chick embryo cells in a shell-less culture. A dose-response relationship for the killing effect of 4HAQO on 2-day embryos was observed in the range of 0.24-24 nmol 4HAQO per embryo. The practicality of the present method of administration of 4HAQO for 'flash administration' of compounds to chick embryo and the advantages of the shell-less culture method which provides access for biochemical and developmental studies of chick embryos were also discussed.

4-Hydroxyaminoquinoline-1-oxide↗
PubMed1976

Serum protein synthesis in the early chick embryo.

Isolated yolk-sacs of chick embryos secreted serum proteins when incubated in buffered chick Ringer's solution. The presence of serum transferrin, two embryo-specific alpha-globulins, and a prealbumin were demonstrated by acrylamide gel analysis. Yolk-sacs from embryos explanted at 11-13 somites (40 hr preincubation) and cultured for 48 hr secreted in addition a protein with the mobility of serum albumin. Incubation of yolk-sacs in the presence of radioactive valine indicated that serum proteins were synthesized as early as the primitive streak stage. By incubating isolated yolk-sacs and embryos from 48-hr explants in the presence of radioactive valine, the synthesis of serum proteins was found to be restricted to the yolk-sac at this stage of development. Culturing explants on various nutrient proteins as well as protein starvation medium altered the relative synthesis of several serum proteins. We have proposed that morphological and biochemical changes in embryos resulting from altered nutrition may be mediated by the proteins of the serum.

Animals↗
PubMed1980

Protective value of gamma globulin preparations against group B streptococcal infections in chick embryos and mice.

The protective value of pooled human gamma globulin (GG) and a group B streptococcal immune globulin (GBSIG) was studiedf in a chick embryo and a murine model of group B streptococcal (GBS) infection. Chick embryos were protected by the IV administration of 0.4 to 0.8 mg of GG from three manufacturers against IV challenge with type Ia GBS. Two of three GG preparations at doses of 0.4 to 1.65 mg protected chick embryos against type III, but 1.65 mg of all three preparations failed to protect against GBS types Ib and II. MIce were protected from lethal IP challenges with types Ia and Ib by the prior IM inoculation of three and two of the three GG preparations at doses of 0.5 to 1.0 mg, respectively. Administration IM of 1 mg of GG failed to protect mice against types II and III. The IV administration of 0.2 mg of GBSIG protected chick embryos against IV inoculation with GBS types Ia, Ib, II, and III. Administration IM of 0.5 mg of GBSIG protected mice against IP challenges with types Ia, Ib, and II, but not with type III. The IP administration of 0.25 mg of GBSIG simultaneously with type III GBS protected mice, whereas GG was not protective. GBSIG should undergo clinical trials for the prevention of GBS infections and their recurrences and as a possible adjunct to antibiotic and supportive therapy of severe GBS infections.

Animals↗
PubMedDate not supplied

Effects of brief hypoxia and hyperoxia on tissue trace element levels in the developing chick embryo.

Brief hypoxia or hyperoxia has been shown to affect growth and metabolism of chick embryos during the late stages of development. The objective of this study was to alter the availability of oxygen to chick embryos developing in ovo and to determine the effects on tissue zinc, copper, iron and manganese levels. On day 15 of incubation fertile chicken eggs were divided into three groups: 15% O2 (hypoxic), 60% O2 (hyperoxic) and 21% O2 (normoxic) and incubated under these conditions for 72 h to day 18. Hypoxia reduced embryo, heart, brain and liver wet weights, whereas hyperoxia increased embryo, heart, lung and liver wet weights compared to normoxic controls. Chorioallantoic membrane (CAM) wet weight was increased by hypoxia and reduced by hyperoxia. Livers from hyperoxic embryos contained more zinc, iron and manganese and less copper than livers from hypoxic or normoxic embryos. Tissue concentrations of zinc, copper, iron and manganese were reduced in brains from hyperoxic compared to hypoxic or normoxic embryos. Hyperoxia increased the zinc and copper concentrations in CAM, whereas hypoxia reduced zinc and iron levels. The contents of zinc and copper were increased in hyperoxic compared to normoxic or hypoxic lungs. Hearts from hyperoxic embryos had more zinc, copper and manganese than hypoxic or normoxic hearts. Hypoxic yolk sac contained more zinc and manganese than hyperoxic or normoxic yolk sac. Except for yolk sac, the trace element content of tissues from normoxic embryos increased from day 15 to day 18 of incubation in concert with tissue growth. We conclude that the availability of oxygen to the developing chick embryo affects tissue trace element levels through its effects on tissue growth, as a result of adaptation by specific tissues to different oxygen tensions, or via effects on the regulation of trace element uptake and assimilation by the tissues.

Allantois↗
PubMed1990

Lack of effect of exogenous insulin-like growth factor-I (IGF-I) on chick embryo growth rate.

Direct evidence that IGF-I has any significant effect on embryo growth is lacking. We therefore studied the effect of administration of IGF-I on the chick embryo in ovo. Five hundred ng pure IGF-I (purified from human plasma) were given to chick embryos on 2 occasions (7 and 14 d) by injection directly into the allantoic sac. Treated and control (saline injected) chicks hatched on the same day and were killed. IGF-I appeared to reach the tissues as the [35S]-sulphate uptake of treated sternal cartilage was significantly greater than that of control (P less than 0.02). However, there were no significant effects of treatment on total body weight, bone length measurements, organ (lung, liver, heart) weights, muscle DNA, RNA or protein levels. From these results we conclude that administration of exogenous IGF-I to the chick embryo at 7 and 14 d does not stimulate further growth of the chick embryo.

Animals↗
PubMed1986

Hemodynamic effects of environmental hyperthermia in stage 18, 21, and 24 chick embryos.

Environmental hyperthermia is a hazard to the poikilothermic chick embryo. We studied effects of hyperthermia on mean vitelline arterial blood pressure and mean dorsal aortic blood flow in stage 18, 21, and 24 chick embryos. The pressure was measured with a servo-null micropressure system, and the blood flow was measured with a 20 MHz pulsed Doppler flowmeter. Temperature was monitored with a needle thermoprobe positioned adjacent to the embryo. Data were obtained at 37 degrees C, after warming to 40 degrees C, and then after cooling to 37 degrees C. At stage 21, the pressure increased from 0.96 +/- 0.05 (+/- SE) to 1.04 +/- 0.06 mm Hg on warming and returned from 1.05 +/- 0.04 to 0.87 +/- 0.04 mm Hg on cooling. Pressure measurements during warming and cooling were performed in two separate groups of embryos because of technical problems. The blood flow, studied using different groups of the embryo from the pressure study, also increased from 0.65 +/- 0.06 to 0.75 +/- 0.06 mm3/s on warming and returned to 0.56 +/- 0.05 mm3/s. The heart rate increased from 173 +/- 2 to 211 +/- 3 at 40 degrees C and returned to 170 +/- 3 at 37 degrees C. Stroke volume (flow/heart rate) did not change during the temperature variation. Vascular resistance, the quotient of pressure to blood flow obtained by a ratio analysis, changed from 1.53 +/- 0.33 (median +/- 95% confidence interval) to 1.42 +/- 0.29 mm Hg/mm3/s on warming and changed to 1.60 +/- 0.32 mm Hg/mm3/s on cooling. Similar results were obtained at stages 18 and 24.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Effect of L-azetidine-2-carboxylic acid on glycosylations of collagen in chick-embryo tendon cells.

The glycosylations of hydroxylysine during collagen biosynthesis in isolated chick-embryo tendon cells were studied by using pulse-chase labelling experiments with [14C]-lysine. The hydroxylation of lysine and the glycosylations of hydroxylysine continued after a 5 min pulse label for up to about 10 min during the chase period. These data differ from those obtained previously in isolated chick-embryo cartilage cells, in which, after a similar 5 min pulse label, these reactions continued during the chase period for up to about 20 min. The collagen synthesized by the isolated chick-embryo tendon cells differed markedly from the type I collagen of adult tissues in its degree of hydroxylation of lysine residues and glycosylations of hydroxylysine residues. When the isolated tendon cells were incubated in the presence of L-azetidine-2-carboxylic acid, the degree of glycosylations of hydroxylysine during the first 10 min of the chase period was identical with that in cells incubated without thcarboxylic acid for at least 60 min, whereas no additional glycosylations took place in the control cells after the 10 min time-point. As a consequence, the collagen synthesized in the presence of this compound contained more carbohydrate than did the collagen synthesized by the control cells. Additional experiments indicated that azetidine-2-carboxylic acid did not increase the collagen glycosyltransferase activities in the tendon cells or the rate of glycosylation reactions when added directly to the enzyme incubation mixture. Control experiments with colchicine indicated that the delay in the rate of collagen secretion, which was observed in the presence of azetidine-2-carboxylic acid, did not in itself affect the degree of glycosylations of collagen. The results thus suggest that the increased glycosylations were due to inhibition of the collagen triple-helix formation, which is known to occur in the presence of azetidine-2-carboxylic acid.

Animals↗
PubMed1989

[Hypophysis and estradiol secretion in the chick embryo].

Ovaries from 10- to 18-day-old chick embryos hypophysectomized by partial decapitation were cultured in vitro and their estradiol secretion was compared to that of ovaries from control embryos. The production of estradiol was not less in the decapitated than in the control embryos at 15-18 days, neither per ovary nor on the basis of ovarian weight. However, the difference was significant at 10-11 days. These results suggest that the hypophysis controls estradiol secretion by the chick embryo ovary in the early stages, but not in the later ones.

Animals↗
PubMed1988

Tryptophan 2,3-dioxygenase in chick embryo hepatocytes: studies in ovo and in culture.

Tryptophan dioxygenase is a hemoprotein in its active form, which has a relatively low affinity for heme. From previous studies in rats, the ratio of holoenzyme/total enzyme activity of tryptophan dioxygenase has been proposed to reflect the size of a "free" heme pool in hepatocytes. Chick embryo hepatocytes in ovo and in culture are other systems that have proven useful for study of hepatic heme metabolism and its control. Heretofore, there have been few studies of tryptophan dioxygenase activity in chick embryo hepatocytes. As part of studies on hepatic heme metabolism, using two different assays, we have measured tryptophan dioxygenase activity and percentage of heme saturation of the enzyme in chick embryo livers cells in ovo and in culture. One method of assay relies on endogenous formamidase to generate the final product, kynurenine, which is measured directly, whereas the other method uses a chemical hydrolysis step to form kynurenine which is further diazotized prior to measurement. The latter method is shown to be preferable for studies with chick embryo hepatocytes. In addition, we show that (i) tryptophan dioxygenase activity is present and can be increased by tryptophan and phenobarbital-like drugs in chick embryo hepatocytes in ovo; (ii) total enzyme activity falls markedly in cultured hepatocytes despite the presence of high concentrations of glucocorticoids in the culture medium; and (iii) under all conditions studied thus far in the cultures, the enzyme is nearly saturated with heme. Results are discussed in relation to regulation of heme metabolism in chick embryo hepatocytes.

Animals↗
PubMedDate not supplied

[Testicular graft on the chick embryo].

A testis from an 18-day-old chick embryo was transplanted into the extra-coelomic cavity of 3-4-day-old hosts. The embryos surviving at 17 days were sacrificed and their genital system was examined. Testis grafting produced inhibition of testicular development. Development of the female gonads was also inhibited. A more or less complete modification of sex was associated with this inhibition. The left ovary lost its cortex, but its medulla remained mostly ovarian in structure. The right gonad frequently acquired a typical testicular structure. These results confirm the possibility of obtaining sex reversal in the female chick embryo by testis grafting.

Animals↗
PubMed2000

Asymmetric expression of antivin/lefty1 in the early chick embryo.

Mammalian lefty and zebrafish antivin, highly related to lefty, are shown to be expressed asymmetrically and involved in the specification of the left body side of early embryos. We isolated a chick homologue of the antivin/lefty1 cDNA and studied its expression pattern during early chick development. We found that antivin/lefty1 is expressed asymmetrically on the left side of the prospective floorplate, notochord and lateral plate mesoderm of the chick embryo.

Amino Acid Sequence↗
PubMed1995

Development of regulation of melatonin release in pineal cells in chick embryo.

Melatonin release in a pineal cell culture from 13- and 14-day-old chick embryos increased during the dark phase and decreased during the light phase of a 12 h light:12 h dark cycle. When the light-dark cycle was reversed, the pattern of melatonin release in the culture also reversed. 8-Bromo cyclic-AMP stimulated melatonin release in both the light and dark phases. However, no rhythm of melatonin release was detected under constant dark (DD) conditions in a cell culture from 14-day-old chick embryos. In 18-day-old chick embryos, the pineal cell culture expressed a circadian rhythm of melatonin release under DD conditions. These results indicate that mechanisms regulating melatonin synthesis in the avian pineal gland are established during embryonic life.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMedDate not supplied

The effect of forskolin on the teratogenicity of methylxanthines in the chick embryo heart.

Interactions between forskolin and methylxanthines, including caffeine and isobutylmethylxanthine (IBMX), in the developing chick embryo heart were investigated. Forskolin, a potent activator of adenylate cyclase, was administered to young chick embryos (Hamburger-Hamilton stage 24) together with caffeine or IBMX at doses where each agent alone caused minimal embryotoxicity. The incidence of malformation in the embryonic chick heart or aorta induced by caffeine (5 x 10(-7) or 5 x 10(-6) mol) and IBMX (1 or 2.5 x 10(-6) mol) significantly increased with coadministration of forskolin (1 x 10(-9) mol). Cardiovascular malformations included ventricular septal defect, double outlet right ventricle, and aortic arch anomalies. These results indicate that forskolin potentiates the teratogenicity of caffeine or IBMX on the cardiovascular system in the chick embryo and suggest that this potentiation may be related to increase intracellular cAMP due to stimulation of adenylate cyclase (forskolin) and inhibition of phosphodiesterase (methylxanthines).

1-Methyl-3-isobutylxanthine↗
PubMed1983

Fine structural aspects of the development of Ito cells (vitamin A uptake cells) in chick embryo livers.

The development of Ito cells in the chick embryo liver was studied using electron as well as fluorescence microscopes. The collagen fibrils in the Disse's space can already be seen in 6-day-old chick embryos. This space contains fibroblast-like cells which should be called primitive Ito cells. They are slender cells characterized by numerous free polyribosomes. The rough endoplasmic reticulum, Golgi apparatus and 10 nm microfilaments are also well developed. The fluorescence of vitamin A and lipid droplets begin to appear in the primitive Ito cell at 9 days of incubation in both the control and vitamin A-treated animals. A special topographic relation between the lipid droplets and cell organelles is difficult to recognize. The primitive Ito cell in the Disse's space acquires the ability to produce collagen fibrils earlier than that of taking up and storing vitamin A. The Ito cells containing lipid droplets increase in number with embryonic age, and about 40-50% of perisinusoid cells have droplets of vitamin A at 21 days of incubation. The droplets are usually less than 1 micron in diameter and do not fuse with each other.

Animals↗