Relation between motoneuron disease and past poliomyelitis

Amyotrophic lateral sclerosis and polio: is there an association?

Because polio and ALS are both manifestations of anterior horn cell disease, consideration of some etiologic or pathogenetic relationship continues to recur. Studies that show an association are infrequent and are greatly outnumbered by negative reports in spite of possible journal bias to report positive results. Our limited studies in Guam and Rochester, Minnesota, have added to the negative list, and support the conclusion that there is no etiologic association of these two distinct diseases. The role, if any, of nonparalytic polio and polio vaccines with respect to ALS is not clear. With such a high proportion of the population having antibodies to polio, it may not be feasible to differentiate ALS with respect to the presence or absence of polio antibodies. Although the results to date do not support a polio-ALS relationship, further long-term studies are desirable for both the classical and the Western Pacific forms of ALS with respect to past polio outbreaks and, for the future, the unknown effect of polio vaccines on the incidence of ALS.

Comparative study of spinal cord ubiquitin expression in post-poliomyelitis and sporadic amyotrophic lateral sclerosis

This study addresses the suggested possible pathogenetic relationship between the late-onset muscular atrophy in patients with the prior diagnosis of poliomyelitis and amyotrophic lateral sclerosis (ALS). For this purpose we applied immunohistochemical techniques to determine the presence of pathological structures that were stained for ubiquitin (a protein involved in degenerative processes) in the spinal cords of patients with a history of poliomyelitis and compared the results with those of ALS, a condition in which cytoplasmic ubiquitin-positive inclusions are invariably found in the anterior horn cells. Our results indicate that post-poliomyelitis patients have no ubiquitin-reactive inclusion bodies in these cells; however, some immunopositive globular and cord-shaped structures are seen in less-affected areas. Similar structures were also found in the spinal cords from patients with ALS and from normal individuals. Our findings would suggest that the pathogenesis of late muscular atrophy in post-poliomyelitis patients is dissimilar to that of ALS.

The use of molecular techniques in studying viral pathogenesis in the nervous system

Molecular biological techniques have been used extensively to gain insights into the pathogenesis of a variety of diseases caused by neurotropic viruses. Increasingly sensitive methods for detecting viral nucleic acids and proteins in pathological nervous tissues have clarified the viral aetiology of certain neurological disorders and are now being used to investigate possible viral involvement in others. In addition, a diverse range of molecular techniques has greatly enhanced our understanding of the molecular basis of viral neurotropism and neurovirulence in both humans and experimental animals. This article provides an overview of these various approaches with examples drawn from both clinical neurological disease and animal models.