scholarly journals The development of sensory projection patterns in embryonic chick hind limb.

1982 ◽  
Vol 330 (1) ◽  
pp. 175-202 ◽  
Author(s):  
M G Honig
Keyword(s):  
Hind Limb ◽  
Embryonic Chick

The appearance of muscle protein and myofibrils within the embryonic chick limb-bud

Development ◽  
1973 ◽  
Vol 30 (3) ◽  
pp. 673-679
Author(s):  
P. V. Thorogood
Keyword(s):  
Banding Pattern ◽  
Hind Limb ◽  
Muscle Protein ◽  
Ventral Surface ◽  
Ultrastructural Level ◽  
Limb Bud ◽  
Embryonic Chick ◽  
Immunofluorescence Technique ◽  
Flexor Muscles

Myotubes are present in the developing hind limb of the embryonic chick at 5 days. An immunofluorescence technique was used to detect actomyosin within the myotubes. The earliest detectable appearance of this muscle protein was at six days of development, at sites located peripherally beneath the flattened dorsal and ventral surface of the limb. These dorsal and ventral loci are interpreted as representing the primordial extensor and flexor muscles. At the ultrastructural level the cytoplasm of the myotubes contains fibrillar components which are apparently aggregating to form myofibrils. A rudimentary banding pattern can be distinguished.

The genesis of membrane bone in the embryonic chick maxilla: epithelial-mesenchymal tissue recombination studies

Development ◽  
1980 ◽  
Vol 56 (1) ◽  
pp. 269-281
Author(s):  
Mary S. Tyler ◽  
David P. McCobb
Keyword(s):  
Bone Formation ◽  
Hind Limb ◽  
Bone Grafts ◽  
Chick Embryos ◽  
Embryonic Chick ◽  
Limb Buds ◽  
Mesenchymal Tissue ◽  
Membrane Bone ◽  
Tissue Recombination

In the present study, the question of whether a relatively non-specific epithelial requirement exists for membrane bone formation within the maxillary mesenchyme was investigated. Organ rudiments from embryonic chicks of three to five days of incubation (HH 18–25) were enzymatically separated into the epithelial and mesenchymal components. Maxillarymesenchyme (from embryos HH 18–19) which in the absence of epithelium will not form bone was recombined with epithelium from maxillae of similarly aged embryos (homotypichomochronic recombination) and of older embryos (HH 25) (homotypic-heterochronicrecombination). Heterotypic recombinations were made between maxillary mesenchyme (HH 18–19) and the epithelium from wing and hind-limb buds (HH 19–22). Recombinants were grown as grafts on thechorioallantoic membranes of host chick embryos. Grafts of intact maxillae, isolated maxillary mesenchyme, and isolated epithelia from the maxilla, wing-, and hind-limb buds weregrown as controls. The histodifferentiation of grafted intact maxillae was similar to that in vivo; both cartilage and membrane bone differentiated within the mesenchyme. Grafts of maxillary mesenchyme (from embryos HH 18–19) grown in the absence of epithelium formed cartilage but did not form membrane bone. Grafts of maxillary mesenchyme (from embryos HH 18–19) recombined with epithelium in homotypichomochronic, homotypic-heterochronic, and heterotypic tissue combinations formed membrane bone in addition to cartilage. These results indicate that maxillary mesenchyme requires the presence of epithelium to promote osteogenesis and that this epithelial requirement is relatively non-specific in terms of type and age of epithelium.

An analysis of the condensation process during chondrogenesis in the embryonic chick hind limb

Development ◽  
1975 ◽  
Vol 33 (3) ◽  
pp. 581-606
Author(s):  
P. V. Thorogood ◽  
J. R. Hinchliffe
Keyword(s):  
Hind Limb ◽  
Mesenchymal Cell ◽  
Cell Number ◽  
Limb Bud ◽  
Condensation Process ◽  
Embryonic Chick ◽  
Cellular Events ◽  
Cell Counts

An analysis has been made of the pre-cartilaginous condensation stage in the development of the femur and tibia/fibula skeletal blastemata of the embryonic chick hind limb. Light microscopy serial sections were used to ‘map’ the mesenchymal cell condensations of both myogenic and chondrogenic anlagen in the limb-bud from stages 22 to 26 (Hamburger & Hamilton, 1951). Cell counts reveal that an increase in mesenchymal cell number per unit area occurs in the central chondrogenic locus at stage 24 (4½ days) prior to matrix formation. Electron microscopy, using a simultaneous double fixation with osmium and glutaraldehyde, reveals that the pre-chondrogenic cells are characterized by large areas of close surface contact between adjacent cells, as compared with the extensive intercellular spaces associated with undifferentiated mesenchymal cells. The results are discussed and related to other investigations of in vivo chondrogenesis and to analyses of cellular events during in vitro chondrogenesis. These observations are consistent with the theory that condensations are formed by a process of aggregation rather than by localized increased mitosis.

Dexamethasone Effect on Embryonic Chick Respiratory Epithelium

1982 ◽  
Vol 40 ◽  
pp. 248-249
Author(s):  
M.R. Richter ◽  
R.V. Blystone
Keyword(s):  
Lung Development ◽  
Critical Role ◽  
Respiratory Epithelium ◽  
Chick Embryos ◽  
Embryonic Chick ◽  
White Leghorn ◽  
Lung Maturation ◽  
Synthetic Analogs ◽  
Lung Physiology ◽  
Avian Lung

Dexamethasone and other synthetic analogs of corticosteroids have been employed clinically as enhancers of lung development. The mechanism(s) by which this steroid induction of later lung maturation operates is not clear. This study reports the effect on lung epithelia of dexamethasone administered at different intervals during development. White Leghorn chick embryos were used so as to remove possible maternal and placental influences on the exogenously applied steroid. Avian lung architecture does vary from mammals; however, respiratory surfactant produced by the lung epithelia serves an equally critical role in avian lung physiology.

Depression of Collateral Blood Flow Following Arterial Thrombosis

1977 ◽  
Vol 38 (04) ◽  
pp. 0850-0862 ◽  
Author(s):  
Robert G. Schaub ◽  
Ronald Sande ◽  
Kenneth M. Meyers
Keyword(s):  
Blood Flow ◽  
Arterial Thrombosis ◽  
Hind Limb ◽  
Therapeutic Interventions ◽  
Collateral Blood Flow ◽  
Serotonin Antagonist ◽  
Limb Perfusion ◽  
Clinical Consequences ◽  
Collateral Vessels ◽  
Iliac Bifurcation

SummaryPermanent ligation of the feline aorta at the iliac bifurcation is followed by rapid opening of pre-existing collateral blood vessels. However, if ligation is combined with formation of a clot, these protective collateral vessels do not function. This study was undertaken to determine if drugs which alter serotonin function can improve collateral blood flow after arterial thrombosis. Permanent ligations were placed at the iliac bifurcation, circumflex iliac and sixth lumbar arteries in all cats. A clot was produced in the aorta of 27 cats by injection of 0.1 ml of thromboplastin. Ligated clot-occluded cats were untreated (10); had blood serotonin depleted using a single dose of reserpine (0.1 mg/kg i. m.) followed by para-chlorophenylanine (p-CPA) (100 mg/kg orally) every 3 days (9) ; or were treated prior to surgery with a serotonin antagonist cinanserin HC1 (4 mg/kg i. v.) (8). Control cats (18) were acutely ligated. 9 of these cats were untreated, 5 were cinanserin HC1-treated, and 4 were reserpine/p-CPA-treated. Extent of collateral development was assessed by aortograms 3 days after occlusion and by neurologic rating. Aortograms of acutely ligated cats indicated a significant collateral blood flow around the segment of ligated aorta, while ligated clot-occluded cats had a severely depressed hind-limb perfusion. Reserpine/p-CPA-treated ligation clot-occluded cats had aortograms similar to acutely ligated cats. The cinanserin HC1-treated ligation clot-occluded cats had aortograms which indicated hind-limb perfusion was not as adequate as the acutely ligated cats. However, the perfusion of these animals was improved over untreated ligation clot-occluded cats. Neurologic rating correlated with aortograms. These results suggest: 1) the clinical consequences of arterial thrombosis cannot be entirely attributed to mechanical occlusion of an artery, but may be due to depression of protective collateral blood flow induced by thrombosis, 2) serotonin is an important factor in this depression of collateral blood flow, and 3) isolation of the factors responsible for collateral inhibition could permit the development of therapeutic interventions.

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