Motor Neuron Atrophy Research Articles

Long-term changes in the spinal cords of patients with old poliomyelitis. Signs of continuous disease activity.

In a retrospective study, we reviewed sections from the spinal cords from eight patients, aged 36 to 61 years, who had had poliomyelitis and who died of nonneurologic diseases nine months to 44 years (mean, 20.7 years) after the acute poliomyelitis infection. Five patients had stable postpoliomyelitis deficits without new symptoms, and three patients had new slowly progressive muscle weakness defined as postpoliomyelitis progressive muscular atrophy (PPMA). Representative spinal cord sections matched the patients' clinical involvement in both groups. Control tissues from ten patients with amyotrophic lateral sclerosis and five with spinocerebellar degeneration were examined simultaneously. The spinal cord segments from all patients who had had poliomyelitis showed loss or atrophy of motor neurons, severe reactive gliosis (disproportional to the neuronal loss), and a surprising mild to moderate perivascular and interparenchymal inflammation. There was no difference in these pathologic changes between the patients with stable postpoliomyelitis deficits and those with PPMA. Additional findings were axonal spheroids (dystrophic axons) and occasional chromatolytic neurons in the spinal cord of patients with PPMA. Corticospinal tracts were spared.

Histochemical and morphological changes in human muscle spindle in upper and lower motor neuron lesions.

The human intrafusal fibers were found to consist of two morphological and three histochemical (ATPase reaction) types. Two types of nuclear bag fibers were seen. Type A showed alkali stable and acid labile and Type B showed acid and alkali stable ATPase reaction. The nuclear chain fibers showed only alkali stable ATPase reaction. In the lower motor neuron atrophy, muscle spindle showed thickening of the capsule, atrophy of the nuclear chain fibers, and splitting of the nuclear bag fibers. ATPase reaction showed targetoid Type B nuclear bag fibers and 2 types of nuclear chain fibers. Oxidative enzymes also showed targetoid nuclear bag and chain fibers. In upper motor neuron atrophy the spindle showed no changes.

Dantrolene in Amyotrophic Lateral Sclerosis

To the Editor.— In relation to the article by Dr. Michael H. M. Dykes (231:862, 1975), our experience using the muscle relaxant dantrolene sodium (Dantrium) in patients with amyotrophic lateral sclerosis (ALS) may provide additional information on side effects and precautions. Dantrolene has been used in controlling spasticity resulting from disorders such as spinal cord injury, brain damage secondary to birth trauma, multiple sclerosis, and stroke. Although the spastic syndromes associated with motor neuron manifestations in ALS are not mentioned in the literature 1-3 or in the package insert by the company producing the drug, it would seem justifiable to use this muscle relaxant because this syndrome affects the corticospinal pathways, producing spasticity that interferes with motor function and rehabilitation. Amyotrophic lateral sclerosis comprises a group of progressive diseases in which variable degrees of atrophy of motor neurons and degeneration of the corticospinal tracts are the common pathological results: Progressive