Ubiquitin-immunoreactive skein-like inclusions in the neostriatum are not restricted to amyotrophic lateral sclerosis, but are rather aging-related structures

We examined the presence of ubiquitin-immunoreactive skein-like inclusions (SLI) in the neostriatum and spinal cord in normal individuals and patients with different neurodegenerative diseases. Ubiquitin-immunoreactive SLI in the neostriatum were observed both in the normal individuals and in the pa tients with a variety of neurodegenerative diseases. In particular, SLI wer e frequently seen in normal aged subjects and certain neurodegenerative dis eases, such as progressive supranuclear palsy and myotonic dystrophy. In co ntrast, the occurrence rate of SLI in cases with Pick's disease and multipl e system atrophy tended to decrease. On the other hand, SLI in the spinal a nterior horn were detected in cases of amyotrophic lateral sclerosis, but n ot in any cases with other neurodegenerative diseases. SLI in the neostriat um were also identifiable using phosphotungstic acid-hematoxylin and Gomori trichrome staining. Ubiquitin immunoelectron microscopy demonstrated that the SLI in the neostriatum corresponded to bundles of filaments. These feat ures of SLI in the neostriatum were quite similar to those of intracytoplas mic rod-like inclusions (RLI) in the large neurons of caudate nucleus, whic h were first described by Kojima and Ogawa in 1974. Our findings indicate t hat SLI in the neostriatum are ubiquitin-related structures whose occurrenc e increases by aging, and less frequently accompany several neurodegenerati ve diseases, and are identical to at least some RLI.