Effects produced by the administration of high doses of 1,25-dihydroxycholecalciferol to the chick embryo

1978 ◽  
Vol 26 (1) ◽  
pp. 221-226 ◽  
Author(s):  
Roberto Narbaitz ◽  
Susan Tolnai
Keyword(s):  
Chick Embryo ◽  
High Doses

85Sr uptake by the chick embryonic heart: Effect of high doses of isoproterenol

1992 ◽  
Vol 70 (7) ◽  
pp. 959-962 ◽  
Author(s):  
I. Oštádalová ◽  
B. Oštádal
Keyword(s):  
Chick Embryo ◽  
Intracellular Calcium ◽  
Embryonic Heart ◽  
Developmental Changes ◽  
Chick Embryos ◽  
Embryonic Tissues ◽  
High Doses

The aim of the present study was to establish whether intraamnial administration of toxic doses of isoproterenol to chick embryos increases cardiac accumulation of strontium, the homologue element of calcium. It has been shown that the ability of embryonic tissues (blood, heart, and liver) to accumulate 85Sr decreases significantly during ontogeny. Administration of isoproterenol to chick embryos did not elevate the concentration of 85Sr in the heart. It seems, therefore, that isoproterenol-induced developmental changes in the chick embryonic myocardium are not necessarily due to intracellular calcium (as measured by 85Sr) overload.Key words: heart, isoproterenol, radiostrontium, chick embryo.

Evidence for the presence of adrenergic receptors in 3-day-old chick embryo

1977 ◽  
Vol 232 (3) ◽  
pp. H250-H254
Author(s):  
L. B. Petery ◽  
L. H. Van Mierop
Keyword(s):  
Chick Embryo ◽  
Pressor Response ◽  
Venous Blood ◽  
Hypotensive Effect ◽  
Pressor Effect ◽  
Alpha Receptors ◽  
Blood Pressures ◽  
High Doses ◽  
Adrenergic Blocking ◽  
Depressor Effect

Effects of sympathomimetic amines without and with alpha and beta-adrenergic blocking agents on the heart rate and arterial and venous blood pressures in the 3-day-old chick embryo were studied. No chronotropic effect was observed. Norepinephrine caused a biphasic change in systolic and diastolic arterial pressures, the lower doses effecting a fall, and the higher doses a rise in these pressures. With phenylephrine a sharp rise in systolic, diastolic, and pulse pressures was seen. Isoproterenol caused a dramatic fall in systolic, diastolic, and pulse pressures. In the presence of phenoxybenzamine, the pressor effect of high doses of norepinephrine was reversed, the pressor effect of phenylephrine was abolished, and the hypotension with isoproterenol was enhanced. After propranolol, the hypotensive effect of low doses of norepinephrine was reversed, the pressor response to phenylephrine was unchanged, and the depressor effect of isoproterenol was abolished. These findings suggest the presence of functioning alpha- and beta-receptors in the 3-day-old chick embryo. Additionally, they suggest that the alpha-receptors develop more slowly in the chick embryo.

The bursa of Fabricius of the chicken embryo: localization and ontogenic evolution of sex-steroid target cells

Development ◽  
1981 ◽  
Vol 63 (1) ◽  
pp. 225-231
Author(s):  
Jean-Marie Gasc ◽  
Walter E. Stumpf
Keyword(s):  
Chick Embryo ◽  
Steroid Hormones ◽  
Normal Development ◽  
Bursa Of Fabricius ◽  
Sex Steroid ◽  
Target Cells ◽  
Immune Organ ◽  
Receptor Sites ◽  
High Doses ◽  
Autoradiographic Technique

Androgenic hormones induce inhibition or regression of the bursa of Fabricius in the chick embryo. The high doses of hormones necessary to this involution raises the question of the processes involved and their putative role in the normal development of the bursa. If androgens play a role it is mediated by receptor sites in target cells. Using an autoradiographic technique, receptor sites for androgenic hormones were localized in mesenchymal cells of the bursa from the primordium (7-day embryo) up to the fully differentiated immune organ (15-day embryo). No target cells containing receptor sites in their nuclei were observed in the endodermic epithelium or the follicles. Oestrogen target cells in very small number are found in the mesenchyme of the bursa, in 15-day embryos. The early presence of receptor sites for steroid hormones in the bursa of Fabricius shows that the normal development may be influenced by androgens, but the actual effects are yet to be demonstrated.

Ultrastructural Localization of Acetylcholinesterase in the Arcuate Nucleus and Median Eminence of the Rat

1977 ◽  
Vol 35 ◽  
pp. 440-441
Author(s):  
K.A. Carson ◽  
C.B. Nemeroff ◽  
M.S. Rone ◽  
J.S. Kizer ◽  
J.S. Hanker
Keyword(s):  
Choline Acetyltransferase ◽  
Median Eminence ◽  
Arcuate Nucleus ◽  
Cholinergic Neurons ◽  
Ultrastructural Localization ◽  
Male Rats ◽  
Neonatal Rats ◽  
Good Marker ◽  
Chemical Studies ◽  
High Doses

Biochemical, physiological, pharmacological, and more recently enzyme histo- chemical data have indicated that cholinergic circuits exist in the hypothalamus. Ultrastructural correlates of these pathways such as acetylcholinesterase (AchE) positive neurons in the arcuate nucleus (ARC) and stained terminals in the median eminence (ME) have yet to be described. Initial studies in our laboratories utilizing chemical lesioning and microdissection techniques coupled with microchemical and light microscopic enzyme histo- chemical studies suggested the existence of cholinergic neurons in the ARC which project to the ME (1). Furthermore, in adult male rats with Halasz deafferentations (hypothalamic islands composed primarily of the isolated ARC and the ME) choline acetyltransferase (ChAc) activity, a good marker for cholinergic neurons, was not significantly reduced in the ME and was only somewhat reduced in the ARC (2). Treatment of neonatal rats with high doses of monosodium 1-glutamate (MSG) results in a lesion largely restricted to the neurons of the ARC.

Otoconia formation in the chick embryo

1983 ◽  
Vol 41 ◽  
pp. 572-573
Author(s):  
C.D. Fermin ◽  
M. Igarashi
Keyword(s):  
Chick Embryo ◽  
Inner Ear ◽  
Gallus Domesticus ◽  
The Body ◽  
Abnormal Behavior ◽  
Intensive Study ◽  
Basic Fuchsin ◽  
Gestational Period ◽  
Sensory Epithelia ◽  
Transmission Electron

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.

Morphological Examination of a Herpes-type Virus Indigenous for Tree Shrews

1970 ◽  
Vol 28 ◽  
pp. 160-161
Author(s):  
J. P. Brunschwig ◽  
R. M. McCombs ◽  
R. Mirkovic ◽  
M. Benyesh-Melnick
Keyword(s):  
Electron Microscopy ◽  
Soft Tissue ◽  
Chick Embryo ◽  
Soft Tissue Sarcoma ◽  
Cell Cultures ◽  
Tree Shrew ◽  
Type Virus ◽  
Morphological Examination ◽  
Tree Shrews ◽  
Embryo Cells

A new virus, established as a member of the herpesvirus group by electron microscopy, was isolated from spontaneously degenerating cell cultures derived from the kidneys and lungs of two normal tree shrews. The virus was found to replicate best in cells derived from the homologous species. The cells used were a tree shrew cell line, T-23, which was derived from a spontaneous soft tissue sarcoma. The virus did not multiply or did so poorly for a limited number of passages in human, monkey, rodent, rabbit or chick embryo cells. In the T-23 cells, the virus behaved as members of the subgroup B of herpesvirus, in that the virus remained primarily cell associated.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Hexachlorobenzene toxicity in the rat ovary: II. Ultrastructure induced by medium (10 mg/kg) dose exposure

1992 ◽  
Vol 50 (1) ◽  
pp. 668-669
Author(s):  
Amreek Singh ◽  
Warren G. Foster ◽  
Anna Dykeman ◽  
David C. Villeneuve
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Surface Epithelium ◽  
Morphological Parameters ◽  
Comprehensive Investigation ◽  
Ovary Surface Epithelium ◽  
Rat Ovary ◽  
High Doses

Hexachlorobenzene (HCB) is a known toxicant that is found in the environment as a by-product during manufacture of certain pesticides. This chlorinated chemical has been isolated from many tissues including ovary. When administered in high doses, HCB causes degeneration of primordial germ cells and ovary surface epithelium in sub-human primates. A purpose of this experiment was to determine a no-effect dose of the chemical on the rat ovary. The study is part of a comprehensive investigation on the effects of the compound on the biochemical, hematological, and morphological parameters in the monkey and rat.

vitreal cells and specialized phagocytes in the chick embryo retina: A TEM and SEM study

1990 ◽  
Vol 48 (3) ◽  
pp. 330-331
Author(s):  
M.A. Cuadros ◽  
M.J. Martinez-Guerrero ◽  
A. Rios
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Chick Embryo ◽  
Basement Membrane ◽  
Sem Images ◽  
Intimate Contact ◽  
Cellular Processes ◽  
Sem Study ◽  
Free Cells

In the chick embryo retina (days 3-4 of incubation), coinciding with an increase in cell death, specialized phagocytes characterized by intense acid phosphatase activity have been described. In these preparations, all free cells in the vitreal humor (vitreal cells) were strongly labeled. Conventional TEM and SEM techniques were used to characterize them and attempt to determine their relationship with retinal phagocytes.Two types of vitreal cells were distinguished. The first are located at some distance from the basement membrane of the neuroepithelium, and are rounded, with numerous vacuoles and thin cytoplasmic prolongations. Images of exo- and or endocytosis were frequent; the cells showed a well-developed Golgi apparatus (Fig. 1) In SEM images, the cells was covered with short cellular processes (Fig. 3). Cells lying parallel to or alongside the basement membrane are elongated. The plasma membrane is frequently in intimate contact with the basement membrane. These cells have generally a large cytoplasmic expansion (Fig. 5).

Structural Studies on the Eukaryotic Ribosome

1990 ◽  
Vol 48 (1) ◽  
pp. 256-257
Author(s):  
Adriana Verschoor ◽  
Ronald Milligan ◽  
Suman Srivastava ◽  
Joachim Frank
Keyword(s):  
Chick Embryo ◽  
3D Reconstruction ◽  
Single Particle ◽  
Mass Density ◽  
Particle Surface ◽  
Uranyl Acetate ◽  
Electron Microscopic ◽  
Eukaryotic Ribosome ◽  
Negative Stain ◽  
Reconstruction Methods

We have studied the eukaryotic ribosome from two vertebrate species (rabbit reticulocyte and chick embryo ribosomes) in several different electron microscopic preparations (Fig. 1a-d), and we have applied image processing methods to two of the types of images. Reticulocyte ribosomes were examined in both negative stain (0.5% uranyl acetate, in a double-carbon preparation) and frozen hydrated preparation as single-particle specimens. In addition, chick embryo ribosomes in tetrameric and crystalline assemblies in frozen hydrated preparation have been examined. 2D averaging, multivariate statistical analysis, and classification methods have been applied to the negatively stained single-particle micrographs and the frozen hydrated tetramer micrographs to obtain statistically well defined projection images of the ribosome (Fig. 2a,c). 3D reconstruction methods, the random conical reconstruction scheme and weighted back projection, were applied to the negative-stain data, and several closely related reconstructions were obtained. The principal 3D reconstruction (Fig. 2b), which has a resolution of 3.7 nm according to the differential phase residual criterion, can be compared to the images of individual ribosomes in a 2D tetramer average (Fig. 2c) at a similar resolution, and a good agreement of the general morphology and of many of the characteristic features is seen.Both data sets show the ribosome in roughly the same ’view’ or orientation, with respect to the adsorptive surface in the electron microscopic preparation, as judged by the agreement in both the projected form and the distribution of characteristic density features. The negative-stain reconstruction reveals details of the ribosome morphology; the 2D frozen-hydrated average provides projection information on the native mass-density distribution within the structure. The 40S subunit appears to have an elongate core of higher density, while the 60S subunit shows a more complex pattern of dense features, comprising a rather globular core, locally extending close to the particle surface.

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