Experimental study on the formation of the epicardium in chick embryos

1993 ◽  
Vol 187 (3) ◽  
Author(s):  
J�rg M�nner
Keyword(s):  
Experimental Study ◽  
Chick Embryos

Is the re-closure of surgically induced open neural tube defect the repetition of primary neurulation? An experimental study with chick embryos

2001 ◽  
Vol 307 (2) ◽  
pp. 69-72 ◽  
Author(s):  
Sang Ki Chung ◽  
Ki Bum Sim ◽  
Byung-Kyu Cho ◽  
Seung-Kwan Hong ◽  
Kyu-Chang Wang
Keyword(s):  
Experimental Study ◽  
Neural Tube ◽  
Neural Tube Defect ◽  
Chick Embryos ◽  
Surgically Induced

Formation of the Cervical Flexure: An Experimental Study on Chick Embryos

1995 ◽  
Vol 152 (1) ◽  
pp. 1-10 ◽  
Author(s):  
J. Männer ◽  
W. Seidl ◽  
G. Steding
Keyword(s):  
Experimental Study ◽  
Chick Embryos ◽  
Cervical Flexure

Analyse expérimentale de la régulation du nombre des cellules germinales après déficience gonadique chez le poulet

Development ◽  
1974 ◽  
Vol 32 (3) ◽  
pp. 619-635
Author(s):  
Eliane Didier ◽  
Nöel Fargeix ◽  
Yves Bergeaud
Keyword(s):  
Experimental Study ◽  
Germ Cells ◽  
Surgical Excision ◽  
Chick Embryos ◽  
Cellules Germinales ◽  
Control Chick ◽  
The Asymmetry

Experimental study of the regulation of the number of germ cells following gonadial deficiency in the chick Colonization of the genital ridges by germ cells was quantitatively studied in control chick embryos killed at stages 25–29, and in embryos in which a surgical excision of the gonad presumptive area was made previously on the second day. In operated embryos which show a more or less perfect agenesis of one gonad, the number of germ cells counted in genital ridges is lower than the number of germ cells estimated in the same stages of control embryos. The deficit is greater for left gonadic agenesis. The decrease in the total number of germ cells is essentially due to a reduction in the cells colonizing the deficient gonad. There is no excess of germ cells observed in the control gonad. Accordingly, a right side operation strengthens the asymmetry of germ cells distribution, whereas a left side one reduces it. Thus, in birds the regulation of the number of germ cells and the quantitative control of colonisation of the gonads is at the gonad level.

Spinal congenital dermal sinus in a chick embryo model

2009 ◽  
Vol 3 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Jasper van Aalst ◽  
Toon F. M. Boselie ◽  
Emile A. M. Beuls ◽  
Johan S. H. Vles ◽  
Henny W. M. van Straaten
Keyword(s):  
Experimental Study ◽  
Animal Model ◽  
Neural Tube ◽  
Split Cord Malformation ◽  
Dermal Sinus ◽  
Chick Embryos ◽  
In Ovo ◽  
Surface Ectoderm ◽  
Chick Embryo Model ◽  
Congenital Dermal Sinus

Object The origin of spinal congenital dermal sinuses is not known. A local nondisjunction of the closing neural tube and the epidermal ectoderm is thought to be the cause of this malformation. In this experimental study, a nondisjunction was mimicked in chick embryos to create an animal model for the dermal sinus. Methods A piece of amniotic tissue was implanted in the closing neural tube in ovo in chick embryos at 2 days of incubation. A total of 50 embryos were manipulated. After a further incubation time of 2–7 days, the embryos were macroscopically and histologically evaluated. Results Dermal sinus–like anomalies were induced in 24 embryos. The induced abnormalities varied from superficial, epidermal lesions to epidermal dimples continuing as a strand of tissue toward the neural tube. This strand invariably was of nonneuronal origin. Additionally, in 3 embryos a split cord malformation was noted, most likely caused by damage to the neural tube during implantation. Conclusions Implantation of donor amniotic tissue in the closing chick neural tube does result in a dimple, from which a strand of tissue continues to the neural tube in various cases, indicating that formation of a dermal sinus–like anomaly can be successfully induced by experimental continuation of the connection between neural tube and surface ectoderm. This finding strengthens the hypothesis that a human dermal sinus arises after nondisjunction of neural tube and surface ectoderm.

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.

Development of the Foramen Secundum in the Chick as Observed by Scanning Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 212-213
Author(s):  
M.J.C. Hendrix ◽  
D.E. Morse
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Procaine Hydrochloride ◽  
Cardiac Anomaly ◽  
Chick Embryos ◽  
Congenital Cardiac Anomaly ◽  
Septal Defects ◽  
Critical Point Drying ◽  
Scanning Electron

Atrial septal defects are considered the most common congenital cardiac anomaly occurring in humans. In studying the normal sequential development of the atrial septum, chick embryos of the White Leghorn strain were prepared for scanning electron microscopy and the results were then extrapolated to the human heart. One-hundred-eighty chick embryos from 2 to 21 days of age were removed from their shells and immersed in cold cacodylate-buffered aldehyde fixative . Twenty-four embryos through the first week post-hatching were perfused in vivo using cold cacodylate-buffered aldehyde fixative with procaine hydrochloride. The hearts were immediately dissected free and remained in the fixative a minimum of 2 hours. In most cases, the lateral atrial walls were removed during this period. The tissues were then dehydrated using a series of ascending grades of ethanol; final dehydration of the tissues was achieved via the critical point drying method followed by sputter-coating with goldpalladium.

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

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