S. Abe et al., VIRAL BEHAVIOR OF PARACRYSTALLINE INCLUSIONS IN OSTEOCLASTS OF PAGETS-DISEASE OF BONE, Ultrastructural pathology, 19(6), 1995, pp. 455-461
Fresh tissues from six patients with Paget's disease of bone were exam
ined ultrastructurally to investigate whether the characteristic parac
rystalline inclusions in pagetic osteoclasts revealed viral behavior.
These inclusions appeared as microfilamentous aggregates in both nucle
i and cytoplasm of the osteoclasts in all six cases. The filamentous e
lements of the inclusions with a diameter of 11-15 nm showed tubular s
tructures with a central electron-lucent zone measuring 5-7 nm in diam
eter. Viral budding-like structures containing these inclusions were f
ound at the peripheral cytoplasm or cell processes in the ruffled bord
er of some pagetic osteoclasts in two cases. The inclusions in the bud
ding-like structures were often arrayed in a parallel fashion on the c
ytoplasmic side of the cell membranes of extruded cytoplasm or cell pr
ocesses. Virion-like particles were also found in the extracellular sp
aces of the ruffled border. Marked nuclear degeneration was often seen
in pagetic osteoclasts of three cases, although other nuclei in the s
ame osteoclasts appeared normal. The degenerated nuclei showed nuclear
ring formation where destroyed nuclear membranes were seen and disapp
earance of nuclear matrices was noted. Since the modifications were al
ways associated with the accumulation of abundant inclusions, they wer
e probably caused by the inclusions. These findings suggested that the
inclusions showed viral behavior in pagetic osteoclasts, and that the
nuclear modifications were caused by virus infection.