Calcified microspheres as biological entities and their isolation from bone

Citation
Je. Aaron et al., Calcified microspheres as biological entities and their isolation from bone, HISTOCHEM J, 31(7), 1999, pp. 455-470
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Medical Research Diagnosis & Treatment
Journal title
HISTOCHEMICAL JOURNAL
ISSN journal
0018-2214 → ACNP
Volume
31
Issue
7
Year of publication
1999
Pages
455 - 470
Database
ISI
SICI code
0018-2214(199907)31:7<455:CMABEA>2.0.ZU;2-U
Abstract
Calcified microspheres, about 1 mu m in diameter, appear at sites of bone f ormation where they invest the collagenous matrix, become confluent and dis appear. Evidence that the particle boundaries are not lost with compaction but merely deformed is supported in section by the granular histochemical s taining of the inorganic phase for bone salt, lipid, fibronectin and acid p hosphatase in osteomalacic, acid-etched and normal human bone. Their persis tence as discrete objects is confirmed by the application of methods for th eir isolation from the collagenous matrix of immature mouse calvarium and m ature bovine femur. Five methods have been used to extract them and include (i) biochemical, (ii) chemical, (iii) mechanical, (iv) pyrogenous and (v) biological separation. Under the optical microscope, all isolates consisted of similar discrete objects and bridged assemblies, whose birefringence va ried with treatment. After decalcification, their organic 'ghosts' remained . Each isolated microsphere had a complex substructure of clusters of non-c ollagenous calcified filaments surrounding a less dense centre. The filamen ts were 5 nm in diameter with a 5 nm periodicity and regular fine interfila mentous connections. It is concluded that the microspheres are independent, complex, pervasive and central to the containment (i.e. packaging) of calc ium phosphate in bone. Their extraction will enable further analysis.