ISSN:
1432-0533
Keywords:
Arachnoid villi
;
Psammoma body
;
Matrix granule
;
Matrix vesicle
;
Matrix mineral
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The fine structure of the human arachnoid villi was studied to clarify the origin of psammoma bodies. Within the villous surface layer, collagen fibrils and fine granular material clustered forming microcores of variable caliber measuring up to 10 μm. An early stage of psammoma body formation was seen more frequently in these villous microcores than in the meningocytic whorls. The villous microcores contained a large number of membrane-free matrix granules as well as a small number of membranebound matrix vesicles and matrix minerals. The matrix granules were irregularly oval structures with electronlucent halo, measuring 0.05–0.70 μm in diameter. Hydroxyapatite crystals were frequently precipitated within and around the matrix granules which aggregated with calcifying matrix vesicles and matrix minerals. Numerous calcifying matrix granules were present within and around enlarging psammoma bodies. The matrix granules may serve as the principal calcification nidi of psammoma bodies in the human arachnoid villi. The possible mechanisms of matrix granule biogenesis are extrusion of preformed arachnoid cell structures or secretion of fine granular material with its extracellular assemblage.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00687957
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