Biomedical subjects
Publications and source records attributed to C Caponnetto.
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We recorded motor responses evoked by transcranial magnetic stimulation (TMS) in the masseter muscles of 30 patients with amyotrophic lateral sclerosis (ALS), 10 patients with cervical spondylotic myelopathy (CSM) and 22 age-matched normal controls. Responses to direct activation of the trigeminal motor root (R-MEPs) were normal both in ALS and CSM patients. Responses to activation of cortico-bulbar descending fibers (C-MEPs) were absent or delayed in 19 ALS patients (63.3%). Abnormalities of masseter C-MEPs were more frequent than abnormalities of limb MEPs and could be observed both in patients with (77.8%) and without (41.7%) clinical bulbar signs. Masseter C-MEPs were normal in all CSM patients. Recording masseter responses to TMS can reveal the frequent impairment of cortico-bulbar projections in ALS and can be useful in the differential diagnosis of spinal cord compression disorders mimicking ALS because of combination of upper and lower motor neuron signs.
Hereditary neuropathy with liability to pressure palsies (HNPP) is associated with a deletion in chromosome 17p11.2, which includes the gene for the peripheral myelin protein 22 (PMP-22). A "gene dosage" effect is probably the mechanism underlying HNPP, but the amount of PMP-22 mRNA in sural nerves of HNPP patients is highly variable and the role of PMP-22 underexpression in impairing myelination has yet to be clarified. We have studied 6 genetically proven HNPP patients, to evaluate the relationship between PMP-22 mRNA levels, and clinical, neurophysiological, and neuropathological findings. Underexpression of PMP-22 mRNA correlates with disease severity and with mean axon diameter and g ratio, but not with myelin thickness, number of "tomacula," or nerve conduction parameters. Our findings further confirm that underexpression of PMP-22 is the main pathogenetic mechanism underlying the severity of clinical symptoms and signs in HNPP. Smaller axons in sural nerves of HNPP patients with lower PMP-22 levels suggests that underexpression of PMP-22 may also affect axon development.
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We studied the prevalence of ubiquitin-reactive dystrophic neurites in neocortex of cases with Huntington's disease (HD), with a history of dementia lasting from 5 to 8 years before death, and in four age-matched controls. The ubiquitin-reactive neurites, identified as round structures localized outside neuronal and glial cells, were quantified in six microscopic fields of cingulate, 2nd temporal and 2nd parietal cortical gyri. The number of ubiquitin-reactive neurites in HD was 12 to 16 times that of controls in the three cortical areas examined. The finding indicates that in HD neocortex there is a severe degeneration of neuronal processes and suggests that it may represent a pathological correlate of dementia.
The diagnostic relevance of recording motor evoked potentials (MEPs) after electrical stimulation of the cervical region, as compared with conventional needle electromyography (EMG), was evaluated in 26 patients with brachial plexus (BP) damage of different aetiology, severity and topography. MEP abnormalities (absence or latency increase) were observed in at least one muscle of all the patients, with a global incidence of 61.5% of the muscles examined. Neurogenic EMG signs were present in all but one patient with an incidence of 62.2% of the muscles examined. Combining the two methods, the global incidence of abnormalities rose to 69.9%. MEP abnormalities were consistent with the clinical topography and severity of BP lesions and were fairly parallel with EMG findings. Recording MEPs after percutaneous electrical stimulation of the cervical region may be regarded as a rapid, non-invasive method for quantitative electrophysiological assessment of BP damage.
In 70 patients with diabetes mellitus (DM) we recorded the motor evoked potentials (MEPs) following magnetic stimulation of the motor cortex and spinal roots. Central motor conduction time (CMCT) was determined as the difference between MEP latencies after cortical and spinal stimulation. The mean CMCTs for the biceps, thenar and tibialis anterior muscles were prolonged in the DM group, as compared to normal controls, and 21 patients exceeded the CMCT upper confidence limit for at least one muscle. CMCT changes and peripheral conduction velocity abnormalities occurred independently and were related to different clinical parameters. We conclude that a subclinical impairment of central motor conduction is present in 30% of DM patients, independently from the occurrence of a diabetic peripheral neuropathy and possibly reflecting different pathophysiological mechanisms.
A long-term follow-up study was performed on patients with transient global amnesia (TGA) in order to evaluate the prognosis, the recurrence rate and the occurrence of stroke and dementia. 102 patients (57 women, 45 men; mean age 62.8 +/- 9.4 years) were prospectively included and followed up. The follow-up duration ranged between 12 and 241 months with an average value of 82.2 +/- 51.1 (mean +/- SD). The death rate showed no difference from that of sex- and age-matched subjects. TGA recurred in 19 cases (18.63%). Only 4 patients suffered subsequent stroke, and only 3 showed intellectual deterioration. TGA prognosis was shown to be better than that of RIA and lacunar patients.
We studied immunocytochemically with 2 amyloid beta protein (ABP) antisera brains from 5 non-demented elderly subjects with evidence of diffuse periventricular white matter hypodensity on computed tomography. In periventricular white matter of all brains we found ABP reactive deposits arranged around small vessels walls. Furthermore ABP reactive deposits, identical to those currently called diffuse plaques, were detected in neocortex in amount proportional to that of white matter deposits. We suggest that ABP microangiopathy and parenchymal deposition is responsible of white matter rarefaction in a subset of cases with a diffuse hypodensity on CT scan which has been called leukoaraiosis.
The efficacy of Cyproheptadine, a serotonin antagonist, in preventing the cerebral ischemic damage was tested on experimental model of transient global cerebral ischemia in Mongolian Gerbil. The semi-quantitative histological evaluation of the severity of ischemic damage showed a protective effect of Cyproheptadine, mainly in the anterior cortical areas.
61 of 1,590 (3.8%) patients with cerebrovascular disease showed suprabulbar palsy of the pure form (42 patients; 2 had autopsy) and striate form (19 patients; 3 had autopsy). 25 patients with the pallidopyramidal syndrome were included since the clinical picture bordered on the striate form. The pure variety was characterized by dysarthria, dysphagia and automatic voluntary dissociation of facial movements. Half of the patients also had hemiparesis, primitive reflexes and short-step gait. In the striate form, the main signs were dysarthria, dysphagia, automatic voluntary dissociation, rigidity and hypokinesia. Brisk tendon reflexes, primitive reflexes, short-step gait and mental deterioration were also present in half of the patients. The pure variety was caused by multiple infarcts and/or lacunae (85.7%), while the striate form had vascular lesions by computed tomography in only 36.8% of the cases. Histological findings, showing lipohyalinosis of the arterial wall leading to stenosis and occlusion of the lumen and tissue rarefaction and disintegration, support the assumption that microinfarctions, sometimes found only by histopathological examination, are the leading pathogenetic factor in this form. Hypertension, cardiopathy, smoking habit, dyslipemia and diabetes are the most frequent risk factors in both forms.
We describe a case of Lyme disease with a prolonged relapsing-remitting course, in which peripheral facial palsy, optic neuritis and myopathy were associated. After high-dose penicillin therapy the patient completely recovered.
The association between some hypothetical risk factors (previous TIA, hypertension, ECG ischemic abnormalities, diabetes, cigarette smoking, atrial fibrillation, hypercholesterolemia, hypertriglyceridemia, high hematocrit) and lacunar syndromes has been evaluated by a matched sample case-control study involving 108 consecutive, incident cases with lacunar syndrome and 216 hospital control subjects, matched for sex and age. A significant increase of Relative Risk (RR) has been shown for: 1. Previous history of TIA; 2. Hypertension; 3. Smoking; 4. Diabetes. No relevance was shown for: 1. Atrial fibrillation; 2. Hypercholesterolemia; 3. Hypertriglyceridemia; 4. High hematocrit. The analysis of the triplets of subjects (1 case + 2 controls) without hypertension showed a significant RR increase for: 1. Previous history of TIA; 2. Ischemic cardiac abnormalities; 3. Atrial fibrillation. Such findings support the hypothesis that, in a minority of cases with lacunar syndrome, the pathogenetic mechanism could be different from occlusion of penetrating arteries in hypertensive patients.
Data from existent literature and from analysis of 60 personal cases of subarachnoid hemorrhage are examined in order to clarify the etiologic and pathogenetic mechanisms. In about 50% of the patients intracranial arterial aneurysms are found; in a lower percentage arteriovenous malformations or arterial atherosclerotic lesions are seen. Specific activities or events related to the onset of subarachnoid hemorrhage are found in about 50% of the cases.
Albumin and IgG have been determined in the serum and cerebrospinal fluid (CSF) of 64 patients affected by Alzheimer's disease and senile dementia of Alzheimer type (SDAT/AD), 17 multi-infarct dementia (MID) patients and 52 controls. The concentrations of albumin and IgG in the serum and CSF have been taken into account to evaluate the integrity of the blood-brain barrier (BBB) and the occurrence of intrathecal immunological activation in demented patients. Clear-cut signs of BBB damage have been shown only in the group of patients affected by MID, whilst none of the two groups of patients displayed signs of immunological activation, expressed by an increase in IgG index, nor abnormally low CSF/serum ratios for IgG, previously suggested as expressive of a "consumption" of IgG by the brain parenchyma.
The authors are presenting a review concerning the most visible aspects of the research directed to emphasize that Huntington's Chorea cannot be compared, either clinically or pathologically, to Parkinson's Disease. It is a hereditary disease in which we can discern an alteration of some neurotransmitters, neuromodulators, neurohormones that are not necessarily opposite in respect to pathophysiological findings of Parkinson disease.