Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Sequential electron microscopic observations of thymic histogenesis in the toad, Xenopus laevis, reveal that the thymus arises as epithelial buddings of the visceral pouches at Nieuwkoop-Faber stage 40, and acquires its basic histological features at stages 48-49. In the rudiments and the surrounding mesenchyme at stages 43-45, there are non-epithelial cells with pseudopodia, abundant ribosomes, and marginated heterochromatin. These cells, possible precursor cells of thymic lymphocytes, are frequently observed to attach and pass through the basal lamina which coats the thymic rudiment. The proliferation and differentiation of large lymphocytes are evident at stage 47. During stages 48-49 the small lymphocytes, lymphoid cortex and epithelial medulla including the thymic cysts, differentiate, and vascularization occurs. The results provide an ultrastructural basis for recent experimental evidence that the thymus exerts its essential function at stages 47-48. The possibility of non-epithelial derivation of thymic lymphocytes is discussed.
Ackerman,
Morphological studies of the embryonic rabbit thymus: the in situ epithelial versus the extrathymic derivation of the initial population of lymphocytes in the embryonic thymus.
1970, Pubmed
Ackerman,
Morphological studies of the embryonic rabbit thymus: the in situ epithelial versus the extrathymic derivation of the initial population of lymphocytes in the embryonic thymus.
1970,
Pubmed
Curtis,
Ultrastructure of the developing thymus of the leopard frog (Rana pipiens).
1972,
Pubmed
Du Pasquier,
Ontogeny of the immune response in cold-blooded vertebrates.
1973,
Pubmed
Du Pasquier,
Direct evidence for immunoglobulins on the surface of thymus lymphocytes of amphibian larvae.
1972,
Pubmed
Horton,
Ontogeny of the immune response to skin allografts in relation to lymphoid organ development in the amphibian Xenopus laevis Daudin.
1969,
Pubmed
,
Xenbase
Jurd,
Humoral antibodies to soluble antigens in larvae of Xenopus laevis.
1975,
Pubmed
,
Xenbase
Kapa,
Electron-microscopic investigation of the thymus of adult frog (Rana esculenta).
1968,
Pubmed
Kidder,
Cytodynamics and ontogeny of the immune response of Xenopus laevis against sheep erythrocytes.
1973,
Pubmed
,
Xenbase
Klug,
[Submicroscopical cytology of the thymus of Ambystoma mexicanum].
1967,
Pubmed
LeDouarin,
Origin and renewal of lymphocytes in avian embryo thymuses studied in interspecific combinations.
1973,
Pubmed
Leene,
Lymphoid stem cell identification in the developing thymus and bursa of Fabricius of the chick.
1973,
Pubmed
LUFT,
Improvements in epoxy resin embedding methods.
1961,
Pubmed
Manning,
Histogenesis of lymphoid organs in larvae of the South African clawed toad, Xenopus laevis (Daudin).
1969,
Pubmed
,
Xenbase
Moore,
Experimental studies on the development of the thymus.
1967,
Pubmed
Owen,
Tissue interaction in the development of thymus lymphocytes.
1969,
Pubmed
Rambourg,
Electron microscope observations on the carbohydrate-rich cell coat present at the surface of cells in the rat.
1967,
Pubmed
REYNOLDS,
The use of lead citrate at high pH as an electron-opaque stain in electron microscopy.
1963,
Pubmed
Sanel,
Ultrastructure of differentiating cells during thymus histogenesis. A light and electron microscopic study of epithelial and lymphoid cell differentiation during thymus histogenesis in C57 black mice.
1967,
Pubmed
Tachibana,
Development and regeneration of the thymus: the epithelial origin of the lymphocytes in the thymus of the mouse and chick.
1974,
Pubmed
Turner,
Thymic dependence of amphibian antibody responses.
1974,
Pubmed
,
Xenbase
Turpen,
Localization of thymocyte stem cell precursors in the pharyngeal endoderm of early amphibian embryos.
1976,
Pubmed
Volpe,
Thymus: central role in the immune system of the frog.
1975,
Pubmed
