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

Interruption of cardiac output does not affect short-term growth and metabolic rate in day 3 and 4 chick embryos

2000 ◽  
Vol 203 (24) ◽  
pp. 3831-3838 ◽  
Author(s):  
W.W. Burggren ◽  
S.J. Warburton ◽  
M.D. Slivkoff
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Body Mass ◽  
Regression Line ◽  
Heart Beat ◽  
Chick Embryos ◽  
Simple Diffusion ◽  
Significant Difference ◽  
Vertebrate Embryos ◽  
Cervical Flexure

The heart beat of vertebrate embryos has been assumed to begin when convective bulk transport by blood takes over from transport by simple diffusion. To test this hypothesis, we measured eye growth, cervical flexure and rates of oxygen consumption (V(O2)) in day 3–4 chick embryos denied cardiac output by ligation of the outflow tract and compared them with those of embryos with an intact cardiovascular system.Eye diameter, used as the index for embryonic growth, increased at a rate of approximately 4.5-5 % h(−)(1) during the observation period. There was no significant difference (P>0.1) in the rate of increase in eye diameter between control (egg opened), sham-ligated (ligature present but not tied) and ligated embryos. Similarly, the normal progression of cervical flexure was not significantly altered by ligation (P>0.1). V(O2) (ml O(2)g(−)(1)h(−)(1)) at 38 degrees C, measured by closed respirometry, was not significantly different (P>0.1) on day 3 in sham-ligated (14.5+/−1.9 ml O(2)g(−)(1)h(−)(1)) and ligated 17.6+/−1.8 ml O(2)g(−)(1)h(−)(1)) embryos. Similarly, on day 4, V(O2) in sham-ligated and ligated embryos was statistically the same (sham-ligated 10. 5+/−2.9 ml O(2)g(−)(1)h(−)(1); ligated 9.7+/−2.9 ml O(2)g(−)(1)h(−)(1)). Expressed as a linear function of body mass (M), V(O2) in sham-ligated embryos was described by the equation V(O2)=−0.48M+24.06 (r(2)=0.36, N=18, P<0.01), while V(O2) in ligated embryos was described by the equation V(O2)=−0.53M+23.32 (r(2)=0.38, N=16, P<0.01). The regression line describing the relationship between body mass and V(O2) for pooled sham-ligated and ligated embryos (the two populations being statistically identical) was V(O2)=−0.47M+23.24. The slope of this regression line, which was significantly different from zero (r(2)=0.30, N=34, P<0.01), was similar to slopes calculated from previous studies over the same range of body mass.Collectively, these data indicate that growth and V(O2) are not dependent upon cardiac output and the convective blood flow it generates. Thus, early chick embryos join those of the zebrafish, clawed frog and axolotl in developing a heart beat and blood flow hours or days before required for convective oxygen and nutrient transport. We speculate that angiogenesis is the most likely role for the early development of a heart beat in vertebrate 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

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.

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