Biomedical subjects
Publications and source records attributed to V Crespi.
Electrophysiological examination of the peroneal nerve was performed in a group of individuals exposed for professional reasons to vapours of n-heptane. The results suggest a probably specific role of this hydrocarbon compound in provoking "minimal" peripheral nerve damage.
Compound muscle action potentials of the extensor digitorum brevis were obtained in two groups of normal and uraemic subjects by stimulating the deep peroneal nerve at the ankle and at the capitulum fibulae. Particular attention was drawn to the index of desynchronisation supplied by the amplitude change in the muscle potential evoked by distal and proximal stimulation of the same nerve. Statistical studied confirmed the soundness of this index in the normal and in the pathological condition, and showed a significant increase of the values found in uraemic patients. The complex of the data pointed out the advantage of integrating the usual motor conduction velocity determination with the mentioned desynchronisation index.
The F-wave velocity in the central segment (axilla to spinal cord) was studied employing the "collison technique" described by Kimura (1974), and compared with the conduction velocity obtained with the usual methods. In 25 normal subjects the F-wave velocity increased proceeding proximally, reaching the maximum values in the central tract (64.86 +/- 2.23 m/sec in ulnar nerve). In 11 patients affected by motor neurone disease and 11 patients affected by amyotrophic lateral sclerosis the F-wave velocity decreased significantly proceeding proximally and the minimum values were found in the central tract (52.51 +/- 2.15 m/sec in MND and 48.64 +/- 5.60 m/sec in ALS). We therefore suggest the use of F-wave velocity as a more complete element for precise localization of the lesion in the central segment when the motoneurone is primarily involved.
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Peripheral neuropathy often occurs in cryoglobulinemia but the pathogenesis of the peripheral nerve involvement is not completely understood, so that the relation between the reported endoneural changes and neuropathy is not clear. In this study we compared the sural nerve biopsies of 6 cryoglobulinemic patients with or without signs of peripheral neuropathy and all affected by the essential mixed type II form (ECII) and, moreover, of 8 age-matched controls. We found that in all the patients with neuropathy, axonopathy occurred and it was invariably associated with endoneural vessel damage. Moreover, the fiber losses were patchily distributed within the nerve fascicles. On the contrary both nerve fibers and vessels were normal in the patients without clinical and neurophysiological evidence of neuropathy and in controls. Our results support the hypothesis that the endoneural damage observed during ECII is not simply coincidental, but is relevant in the pathogenesis of cryoglobulinemic neuropathy. They also favor the assumption that ischemic damage of the nerve fibers occurs during ECII.
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We report a case of intracerebral hemorrhage (ICH) in a young man following intravenous self-administration of epinephrine. Arteriography evidenced normal intracranial vessels, and namely excluded the presence of vascular malformations which could have been implicated in the pathogenesis of ICH. We believe that the main pathogenetic agent in this case was the sudden rise in arterial blood pressure. This report aims at underlying the severe implications of non-medical use of sympathomimetic drugs.
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Motor and sensory nerve conduction velocity was determined bilaterally, evry 4 h, in 6 healthy volunteers. A circadian rhythm was demonstrated in 18 nerves out of 24. A rhythm for both motor and sensory groups could also be determined. The two rhythms differ significantly.