The diameter histograms of cell bodies (cytons) in motor neuron columns at the L5 segment of the spinal cord of adult man reproducibly yield three peaks of increasing height: small (Cs), intermediate (Ci), and large (Cl). Histograms of L5 myelinated axons obtained from the ventral root have two peaks of increasing height: intermediate (Ai) and large (Al). In histograms prepared from seven cases of amyotrophic lateral sclerosis (ALS), the Cl and Al peaks were decreased selectively and severely. This provides evidence for alpha, but not gamma, motor neuron vulnerability. The Cl peak of spinal ganglion neurons and the Al peak of dorsal roots were significantly reduced in number, without a concomitant increase in Ci, Cs, and Ai peaks. This, plus earlier reports of abnormal cutaneous sensation thresholds, abnormal rates of fiber degeneration in cutaneous nerves, and dorsal column demyelination, provides evidence that large afferent neurons are affected in ALS, but to a lesser degree than alpha motor neurons.
Centrifugal segmental demyelination extended from the proximal to the distal portion, and onion bulb formation in the extraspinal ventral root occurred following the axonal lesion of the intraspinal ventral root induced by 3,3'-iminodipropionitrile. These results suggest that axonal factors may be responsible to segmental demyelination and onion bulb formation.
The selectivity of the impregnation of neurons by the Golgi method was examined by comparing Nissl-stained specimens with Golgi-stained specimens in terms of the somatic orientation, cross-sectional area, and long and short axes of the soma in the ventromedial hypothalamic nucleus (VMH) and lateral hypothalamic area (LHA) of 5-week-old rats. With regard to somatic orientation, we made comparisons directly between the Nissl distribution pattern and the Golgi pattern. The two distribution patterns did not differ significantly in either VMH or LHA (Smirnov test, P greater than 0.05). For somatic cross-sectional area and diameter (long and short), a mean value of every 10% of the total frequency was estimated for each histogram; the histogram was segmented into 10 percentile frequency domains, and a mean value for each domain was estimated. A linear regression was calculated between Golgi mean values and Nissl's at the same place. By use of the linear regression, all of the observed values on Nissl sections for somatic cross-sectional area and diameter were transformed into their corresponding Golgi values. The frequency distribution of these transformed Nissl values was compared with that of the actually observed Golgi values. There was a high degree of similarity between the two distribution patterns in all regions examined for long and short diameters as well as cross-sectional area of the soma (Smirnov test, P greater than 0.05). These findings suggest that the sampling of VMH and LHA neurons in the Golgi method used in the present study is similar to the corresponding sampling in Nissl preparation.(ABSTRACT TRUNCATED AT 250 WORDS)
A 21-year-old man had progressive symmetric, distal muscle atrophy and weakness, as well as spasticity of the limbs. Histologic examination of the sural nerve disclosed swollen axons containing membranous tubular profiles, ring tubules, large mitochondria with abnormal cristae, and glycogen like granules. Peripheral sensory nerve fibers also were affected. The pathologic features of the peripheral nerves were similar to those of infantile neuroaxonal dystrophy. Sural nerve biopsy may be useful in the study of pathologic processes in spastic paraplegia.
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