S Servidei — Page 8 | PubMed Health

PubMedDate not supplied

Morphological studies of sural nerve biopsies in the pseudopolyneuropathic form of amyotrophic lateral sclerosis.

The aim of this work was to study the neuropathological picture of the sural nerve in the pseudopolyneuropathic form of amyotrophic lateral sclerosis (ALS). Five patients were considered: in all cases the clinical and electromyographic follow-up excluded other diseases. EMG-studies were repeatedly performed: they showed the progressive evolution of the spinal anterior horn cell pathology from lower spinal to cervical levels. The sural nerve was removed and immediately fixed in phosphate-buffered 2.5% glutaraldehyde and processed according to the procedure used in our laboratory for light and ultrastructural microscopy. Quantitative analysis of myelinated fiber density was carried out on photographic enlargements of 1 micron semithin sections and recorded on histograms. The light and ultrastructural findings revealed a severe loss of myelinated fibers, the decrease affecting all types of fibers, but predominantly the largest ones. In the teased fibers, Wallerian-like degeneration was observed. In the axons there was an increase of mitochondria, dilatation of the small vesicles, and an increase in the number of neurofilaments. It can be assumed from the histopathologic data that the neuropathologic pattern in the pseudopolyneuropathic form of ALS shows an axonal degeneration. It is our opinion that the histopathologic data obtained in the sural nerve biopsy in this form of ALS reveals a clear involvement of the sensory neurons of the spinal ganglia, and the results can be useful for the study of precocious lesions in ALS.

Adult↗

PubMedDate not supplied

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS).

We report the clinical, pathological, and genetic findings of a case of MELAS syndrome. This was a man who died for metabolic failure at the age of 27 years. His familiar history was positive for hypoacusia and stroke. He was of short stature and presented mild mental retardation. Since the age of 21 he suffered from recurrent brain-ischemic lesions mainly in the occipital lobes, documented by repeated CT scans. The laboratory data and muscle biopsy disclosed lactic acidosis with ragged red fibres. Neurophysiological data and peripheral nerve biopsy showed an axonal neuropathy. A point mutation in the tRNALeu(UUR) gene of mitochondrial DNA was detected in 5 post-mortem tissues and in muscle biopsy. No defects of mitochondrial respiratory chain were detected. The histological and ultrastructural studies of the brain showed multiple and heterogeneous ischemic lesions with no obvious alterations of cerebral blood vessels. These lesions do not correspond to the vascular territories of main cerebral arteries. Our observations support the hypothesis that local metabolic alterations would play a crucial role in the pathogenesis of cerebral ischemic lesions in MELAS. The correlation between genetic, biochemical, and pathological data are discussed.

Adult↗