The several and sometimes paradoxical effects of cortisone and its analogues on the course of a variety of infections may be duplicated in the relatively simple chick embryo-influenza virus model in which the interrelationships of a single obligate intracellular parasite and the cells of a single target organ (the allantoic entoderm) may be examined. Even in this simple system the influence of ...

The establishment of a successful plaque method for counting infectious virus particles by Dulbecco (1952), with subsequent refinements by Dulbecco and Vogt (1953, 1954a), makes it possible to quantitatively assay animal viruses with a high degree of accuracy in a manner comparable to assays of bacterial viruses. Two methods of assay commonly used in characterizing any particular Newcastle dise...

Despite voluminous literature describing the chemical changes which accompany development of the chick embryo, there are few quantitative data on the occurrence of respiratory and glycolytic enzymes and coenzymes. Since these catalysts are concerned with reactions which may be available for the processes of growth and differentiation, more knowledge of their activities during the incubation per...

Chick embryos ranging from the stage of first cleavage to that of about 700 cells were removed from the oviduct and examined by transmission electron microscopy. Beneath the cell membrane is a yolk-free cortical region containing microfilaments. Beneath this lies cytoplasm which contains yolk spheres which are graded in size, the dorsal ones being smaller than the ventral ones. The subgerminal ...

Chick embryos are useful models for probing developmental mechanisms including those involved in organogenesis. In addition to classic embryological manipulations, it is possible to test the function of molecules and genes while the embryo remains within the egg. Here we define conditions for imaging chick embryo anatomy and for visualising living quail embryos. We focus on the developing limb ...

T H E use of specific antisera against different embryonic antigens to detect a correlation between morphological and immunochemical differentiation in ontogenesis has proved to be a valuable technique. In a study of the appearance of lens proteins in chick embryos, using various antisera and agar precipitation methods, we observed the development of precipitation lines which did not correspond...

Although vertebrates display a superficial bilateral symmetry, most internal organs develop and locate with a consistent left:right asymmetry. There is still considerable debate as to when this process actually begins, but it seems that, at least for some species, the initial steps occur at a very early stage of development. In recent years, a number of model systems, including the chick embryo...

The immunological properties of the surface of chick embryo cells infected with strain MC29 avian leukosis virus were investigated by immune electron microscopy in con junction with antiviral and anticellular immune sera. When samples were taken at sequential times after infection, it was found that cells stained strongly for viral antigen very early after infection. Staining reached a minimum ...

Objective: In recent years, amino acids are used in veterinary medicine for many purposes. They injected into hatching eggs to increase chick body weight and performance at hatch, but the adverse effects of amino acids have always been a major concern. There is scant information available about the pathological alterations of amino acids in the chicken embryonated eggs. The objective of this st...

Objective: In recent years, amino acids are used in veterinary medicine for many purposes. They injected into hatching eggs to increase chick body weight and performance at hatch, but the adverse effects of amino acids have always been a major concern. There is scant information available about the pathological alterations of amino acids in the chicken embryonated eggs. The objective of this st...