ISSN:
1432-0878
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Morphological and histochemical studies of the developing human islet cells are facilitated by the characteristic localization of the different islet cell types from about the third intrauterine month. By combining light microscopical analyses of silver impregnated and granule stained pancreatic sections with electron microscopy of osmium fixed material, the following four types of islet cells could be identified: (1) A1 cells containing faint globular granules. These granules could be visualized only with the electron microscope. (2) A2 cells containing electron-dense globular granules. It is uncertain whether the observation of a light and a dark variety of the A2 cells reflects different stages of maturation or signifies cells with different secretion products. (3) B cells with irregular granules, which were often accumulated at the capillary pole of the cells. (4) Agranular islet cells. Mixed forms of A cells containing both faint and dense granules were also encountered. The difficulties in evaluating in the light microscope what may be called D cells in the human fetal islets were obvious from the observation of more cells stained with light-green than A1 cells. Except for acid phosphatases, the histochemical tests for different phosphatases and esterases revealed rather weak or negative reactions in the islet cells. The development of phosphatase and esterase activities in the islets seemed far from complete, when morphologically differentiated islet cells could be recognized.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00319250
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