In ovo Experiments Concerning the Eye, the Orbit, and Certain Juxta-Orbital Structures, in the Chick Embryo

Development ◽  
1962 ◽  
Vol 10 (3) ◽  
pp. 423-450
Author(s):  
P. H. S. Silver

The present communication concerns the influence in the chick (Gallus domesticus) of the growing eyes on various structures which form the wall of the orbits, or which lie in their vicinity. Features of the development of the trabeculae cranii, the fronto-nasal process, the nasal capsules, the maxillary ‘process’, the otic capsule, and the cephalic flexure will be described as well as certain growth relationships of the upper and lower jaws. The methods employed include (1) removal of one or both primary optic vesicles, (2) the grafting of an additional primary vesicle into the head mesenchyme so that two eyes develop in one orbit, and (3) the isolation in the coelom of various head components. The importance of the trabeculae to our present study stems from the fact that they contribute to the boundaries of the orbits on their medial sides.

Author(s):  
C.D. Fermin ◽  
M. Igarashi

Otoconia are microscopic geometric structures that cover the sensory epithelia of the utricle and saccule (gravitational receptors) of mammals, and the lagena macula of birds. The importance of otoconia for maintanance of the body balance is evidenced by the abnormal behavior of species with genetic defects of otolith. Although a few reports have dealt with otoconia formation, some basic questions remain unanswered. The chick embryo is desirable for studying otoconial formation because its inner ear structures are easily accessible, and its gestational period is short (21 days of incubation).The results described here are part of an intensive study intended to examine the morphogenesis of the otoconia in the chick embryo (Gallus- domesticus) inner ear. We used chick embryos from the 4th day of incubation until hatching, and examined the specimens with light (LM) and transmission electron microscopy (TEM). The embryos were decapitated, and fixed by immersion with 3% cold glutaraldehyde. The ears and their parts were dissected out under the microscope; no decalcification was used. For LM, the ears were embedded in JB-4 plastic, cut serially at 5 micra and stained with 0.2% toluidine blue and 0.1% basic fuchsin in 25% alcohol.


Endocrinology ◽  
2013 ◽  
Vol 154 (1) ◽  
pp. 388-399 ◽  
Author(s):  
Youli Hu ◽  
Subathra Poopalasundaram ◽  
Anthony Graham ◽  
Pierre-Marc Bouloux

Fibroblast growth factor (FGF) signaling is essential for both olfactory bulb (OB) morphogenesis and the specification, migration, and maturation of the GnRH-secreting neurons. Disruption of FGF signaling contributes to Kallmann syndrome characterized by both anosmia and sexual immaturity. However, several unanswered questions remain as to which specific FGF receptor (FGFR)-1 signaling pathways are necessary for OB and GnRH neuronal development. Here, using pharmacological phosphatidylinositol 3-kinase (PI3K) isoform-specific inhibitors, we demonstrate a central role for the PI3K p110α isoform as a downstream effector of FGFR1 signaling for both GnRH neuronal migration and OB development. We show that signaling via the PI3K p110α isoform is required for GnRH neuronal migration in explant cultures of embryonic day (E) 4 chick olfactory placodes. We also show that in ovo administration of LY294002, a global PI3K inhibitor as well as an inhibitor to the PI3K p110α isoform into the olfactory placode of E3 chick embryo impairs GnRH neuronal migration toward the forebrain. In contrast, in ovo PI3K inhibitor treatment produced no obvious defects on primary olfactory sensory neuron axonal targeting and bundle formation. We also demonstrate that anosmin-1 and FGF2 induced neuronal migration of immortalized human embryonic GnRH neuroblast cells (FNC-B4-hTERT) is mediated by modulating FGFR1 signaling via the PI3K p110α isoform, specifically through phosphorylation of the PI3K downstream effectors, Akt and glycogen synthase kinase-3β. Finally, we show that neurite outgrowth and elongation of OB neurons in E10 chick OB explants are also dependent on the PI3K p110α isoform downstream of FGFR1. This study provides mechanistic insight into the etiology of Kallmann syndrome.


Development ◽  
1986 ◽  
Vol 95 (1) ◽  
pp. 147-168
Author(s):  
Jane Butler ◽  
Peter Cauwenbergs ◽  
Ethel Cosmos

The extent of interaction between brachial muscles and foreign (thoracic) nerves of the chick embryo was determined during an extended period of development in ovo from the perspectives of innervation pattern, function (motility analyses), muscle growth (quantitative analyses of muscle volume) and fibre-type expression (myosin-ATPase profiles). Results indicated that according to all parameters analysed, initially a compatible union existed between the foreign nerves and their muscle targets. During subsequent stages of development, deterioration of the once compatible relationship emerged, until eventually denervation of muscles, i.e. an actual loss of intramuscular nerve branches, was observed. The process of denervation, which proceeded at a differential rate among individual muscles, however was restricted to brachial muscles derived from the premuscle masses of the wing bud. In contrast, brachial muscles of myotomal origin were spared the fate of wing-bud-derived muscles and maintained a successful union with the foreign nerves.


1988 ◽  
Vol 250 (1) ◽  
pp. 189-196 ◽  
Author(s):  
B C Lincoln ◽  
J F Healey ◽  
H L Bonkovsky

We studied drug- and metal-mediated increases in activity of haem oxygenase, the rate-controlling enzyme for haem breakdown, in chick-embryo hepatocytes in ovo and in primary culture. Phenobarbitone and phenobarbitone-like drugs (glutethimide, mephenytoin), which are known to increase concentrations of an isoform of cytochrome P-450 in chick-embryo hepatocytes, were found to increase activities of haem oxygenase as well. In contrast, 20-methylcholanthrene, which increases the concentration of a different isoform of cytochrome P-450, had no effect on activity of haem oxygenase. Inhibitors of haem synthesis, 4,6-dioxoheptanoic acid or desferrioxamine, prevented drug-mediated induction of both cytochrome P-450 and haem oxygenase in embryo hepatocytes in ovo or in culture. Addition of haem restored induction of both enzymes. These results are interpreted to indicate that phenobarbitone and its congeners induce haem oxygenase by increasing hepatic haem formation. In contrast, increases in haem oxygenase activity by metals such as cobalt, cadmium and iron were not dependent on increased haem synthesis and were not inhibited by 4,6-dioxoheptanoic acid. We conclude that (1) induction of hepatic haem oxygenase activity by phenobarbitone-type drugs is due to increased haem formation, and (2) induction of haem oxygenase by drugs and metals occurs by different mechanisms.


2017 ◽  
Vol 234 (12) ◽  
pp. 1458-1462 ◽  
Author(s):  
Ronja Klose ◽  
Felix Streckenbach ◽  
Stefan Hadlich ◽  
Thomas Stahnke ◽  
Rudolf Guthoff ◽  
...  

ZusammenfassungDie UHF-MRT ist ein hervorragendes Verfahren zur nicht invasiven sowie nicht destruktiven Darstellung verschiedener Gewebe mit unterschiedlichem Weichteilkontrast sowie einem hohen Auflösungsvermögen im µm-Bereich. Das embryonale Auge stellt mit seinen filigranen anatomischen Strukturen genau diese Anforderungen an ein Bildgebungsverfahren. Durch seinen kurzen Entwicklungszyklus ist das Huhn ein beliebtes Tiermodell für embryonale Studien. Als nicht invasives Bildgebungsdiagnostikum erlauben repetitive In-ovo-Untersuchungen am selben Embryo eine Realisierung longitudinaler Studien über den gesamten Entwicklungsverlauf. Am Hühnerembryonenmodell (Gallus gallus domesticus) wurden die Grenzen und Möglichkeiten der In-ovo-Bildgebung bei 7 T evaluiert sowie das Größenwachstum der Embryonen mit Hauptaugenmerk auf die detaillierte Augenentwicklung beschrieben.


Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 369-375
Author(s):  
P. H. S. Silver

It seems to be generally accepted that experimenting in ovo on the chick during the early stages of development (up to about 48 hours) is fraught with the greatest difficulty. After about this time no serious technical problems arise and a high proportion of successful results can be expected. It is natural to ask why there should be this change-over from extreme difficulty to reasonable simplicity. New (1955) attributed to this ‘inaccessibility of the chick embryo in the egg’ the invention of his own and many other in vitro methods during the last 30 years. There is no doubt that, when short-term experiments only are required, in vitro methods will probably always be preferred. But all in vitro methods suffer from the disadvantage that the embryo cannot be expected to survive for more than 48 hours or so after explantation.


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