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Biomedical subjects

P Tonali

Publications and source records attributed to P Tonali.

At least 19 recordsLinked to original sources
PubMed1995

Genetic homogeneity between childhood-onset and adult-onset autosomal recessive spinal muscular atrophy.

Molecular diagnosis of childhood proximal spinal muscular atrophy has been enhanced by the discovery of the survival motor neuron (SMN) gene, which is absent or truncated in 98.6% of patients. To determine whether deletion analysis of the SMN gene may also be diagnostic for adult-onset disease, we studied six patients and found deletions in all. This finding will facilitate the diagnosis of adult-onset spinal muscular atrophy, and provides evidence for genetic homogeneity between the clinically diverse adult and childhood forms of the disease.

Adult↗
PubMed1995

Analysis of peristaltic reflex in young mdx dystrophic mice.

Experiments have been carried out in isolated distal colon of young normal and mdx dystrophic mice, the animal homologous of Duchenne muscular dystrophy. Intraluminal pressure, longitudinal displacement, ejected fluid volume and changes in morphology during peristaltic events were recorded. In both male and female normal animals, pressure waves were observed to be generally regular in shape, amplitude (14.19 +/- 2.45 (SD) cm H2O), frequency (54.00 +/- 10.78 h-1) and duration (31.12 +/- 3.47 s). The propulsive activity resulted in orthograde transport of intraluminal content. Mdx mice exhibited great changes in relation to sex, since clear and more marked dysfunctions were recorded in female mice. In male mdx animals, an increase of intraluminal pressure (22%) and ejected fluid volume (38%) were recorded. In females, a remarkable significant (P < 0.001) increase (78%) of intraluminal pressure was observed. Simultaneous anterograde and retrograde propulsive activity also occurred. Localized annular constrictions in proximal, central and distal portions of colonic segment were observed. The implications of the results are discussed in terms of injury of myogenic and nervous pathways controlling mdx colonic smooth muscle.

Animals↗
PubMed1995

Differential electrophysiological features of neuropathies associated with 17p11.2 deletion and duplication.

UNLABELLED: Hereditary neuropathy with liability to pressure palsies (HNPP) and hereditary motor-sensory neuropathy type IA (HMSN IA) are quite distinct clinical entities recently associated to deletion and duplication, respectively, of the 17p11.2 segment including the gene for peripheral myelin protein 22 (PMP-22). We studied the electrophysiological features of 48 HNPP and 62 HMSN IA motor nerves. Conduction velocities (CV) and compound muscle action potential amplitudes were significantly reduced and distal latencies prolonged in HMSN IA compared to HNPP. CV was uniformly slowed in HMSN IA nerves whereas in HNPP it was focally slowed in 80% of ulnar and 12% of peroneal nerves at usual compression sites. Conduction block was present in 6% of HNPP nerves but in none of HMSN IA. IN CONCLUSION: (1) HMSN IA with 17p11.2 duplication presents marked, diffuse, and uniform slowing; (2) HNPP with 17p11.2 deletion presents focal electrophysiological abnormalities possibly correlated with the presence of tomaculae; and (3) under- and overexpression of PMP-22 in concurrence with environmental factors might be responsible for the distinctive features of HNPP and HMSN IA.

Action Potentials↗
PubMed1995

Motor cortex changes in a patient with hemicerebellectomy.

To evaluate reorganisation of motor pathways following a cerebellar lesion, we studied motor cortex excitatory responses and inhibitory effects after transcranial stimulation, together with segmental spinal cord excitability, in one patient who had undergone hemicerebellectomy. We compared the results obtained using different forms of stimulation capable of activating the cortico-spinal tract at different sites. Results were compared between sides. We previously reported that the threshold for responses is higher in the motor cortex contralateral to the impaired hemicerebellum and the right/left threshold asymmetry is clearly greater than normal when a circular coil centred over the vertex is used. In the present study, using electrical anodal stimulation, no side difference was observed. Significant interside differences were absent also when the durations of the silent periods or the mean amplitude of the flexor carpi radialis H reflex between the two sides were compared. The outcome is that the interside differences previously observed are mainly due to reduction in the intrinsic excitability properties of the motor cortex functionally related to the impaired hemicerebellum and not to modification of the inhibitory properties of the cortex or to spinal mechanisms.

Cerebellum↗
PubMed1995

Origin and distribution of P13 and P14 far-field potentials after median nerve stimulation. Scalp, nasopharyngeal and neck recording in healthy subjects and in patients with cervical and cervico-medullary lesions.

We studied median nerve SEPs in 10 healthy subjects, by means of simultaneous recording over the scalp, around the neck and near the ventral surface of the medulla using a nasopharyngeal (NP) electrode. This recording technique enabled us to clearly differentiate P13 and P14 potentials. The former was always found in NP records, while the latter was more evident in scalp traces. The same technique was used to study 9 patients with various lesions of the cervical cord or cervico-medullary junction. Patients with high cervical lesions demonstrated abnormalities of both P13 and P14 potentials, while patients with lesions of the cervico-medullary junction demonstrated a clear dissociation between normal P13 in scalp and NP traces, and abnormal scalp P14. Patients with lower cervical lesions, selectively involving the central grey matter, showed normal P13 and P14 potentials, in spite of abnormal N13 cervical responses. Our findings strongly suggest that both scalp and NP P13 have the same generators in higher segments of the cervical cord, and that NP more than scalp records are effective in analyzing the P13 response. We suggest that the selective recording of the P13 potential could be useful in the assessment of focal lesions of the higher cervical cord or of the cervico-medullary junction.

Adult↗
PubMed1995

Recovery after surgery of the spinal N24 SEP in dural arteriovenous malformation of the dorsal cord.

We studied somatosensory evoked potentials (SEPs) to tibial nerve stimulation in two patients suffering from dorsal dural arteriovenous malformation (AVM). We found in both patients abnormalities in the lumbar N24 potential and in the cortical P40 response. After surgical removal of the AVM, the N24 recovered in both patients. Cord lesions probably occur in patients with dural AVM because of a theft of blood through the fistula; N24 recovery may therefore be associated with a restoration of blood supply after surgery. The N24 recovery in our patients with dural AVM suggests that the abnormality of this potential does not necessarily reflect irreversible damage to the lumbo-sacral cord and that the N24 recording can be useful in post-surgical monitoring.

Aged↗
PubMed1995

Familial autoimmune myasthenia gravis: report of four families.

Four families each with two patients with autoimmune myasthenia gravis or related conditions are reported. All clinical forms of myasthenia gravis were represented and different disease types were found within the same family. Either one or two generations could be affected and no association with a single HLA haplotype was found. The frequency of familial autoimmune myasthenia gravis is very low and the genetic factors involved seem to be different from MHC genes.

Adult↗
PubMed1995

Multiple system atrophy presenting as parkinsonism: clinical features and diagnostic criteria.

To evaluate the possibility that parkinsonian signs may be the only presenting feature of multiple system atrophy (MSA), parkinsonian patients were studied who had no atypical clinical signs and had no symptoms of autonomic dysfunction, but who reported that they had not experienced the anticipated good response to dopaminergic treatment. These stringent criteria identified 20 patients from a series of 298 consecutive parkinsonian outpatients. The following clinical pointers were analysed: (a) rate of disease progression; (b) symmetry of parkinsonian symptoms and signs; (c) occurrence of resting tremor during the first three years from onset. In addition, all patients underwent (d) acute and chronic challenge with dopaminergic drugs; (e) cardiovascular reflex autonomic function tests; (f) high field MRI. Rapid progression of disease was seen in 45% of patients, onset was symmetric in 25%, tremor was absent at onset in 70%, response to dopaminergic drug challenges was inadequate in 40%, abnormal cardiovascular reflexes occurred in 50%, and some abnormal MRI finding occurred in 35% of cases. Each of these features was equally weighted by giving to each patient a 0 to 6 point score corresponding to the number of abnormal findings. Fifteen patients scoring higher than 1 were considered at risk for having MSA: five of them were classified as clinically possible (score 2), six as clinically probable (score 3-4), and four patients were classified as clinically definite multiple system atrophy (score 5). The six pointers considered were variably combined in each patient, none of them being universally abnormal in patients with high scores. The patients were followed up for a mean 2.1 (SEM 0.65) years. All but one of the 10 patients prospectively classified as probable or definite MSA developed unequivocal clinical signs of fully symptomatic MSA. A receiver operator characteristic cure was plotted for the prospective score based on follow up diagnosis. The best compromise for trade off between sensitivity and specificity was a cut off value at a score of 3. The sensitivity and specificity of the individual pointers considered to predict fully symptomatic MSA varied considerably, and no single item could predict whether patients presenting with just parkinsonian signs went on during the two year follow up period to develop fully symptomatic MSA. Instead, the number of abnormalities offered a predictive value for the clinical prognosis of these parkinsonian patients.

Adult↗
PubMed1995

Myasthenia gravis during interferon alfa therapy.

Patients treated with interferon alfa can develop autoantibodies and autoimmune diseases. We describe two patients who developed myasthenia gravis with abnormal levels of serum anti-acetylcholine receptor antibodies during interferon alfa-2b treatment for malignancies. One of these patients had myopathic findings on EMG and focal deficiency of cytochrome c oxidase on muscle biopsy.

Cytochrome-c Oxidase Deficiency↗
PubMed1994

Cerebro-cerebellar interactions in man: neurophysiological studies in patients with focal cerebellar lesions.

Recently Ugawa and co-workers reported that motor cortex excitability after magnetic stimulation in man can be reduced by coupling an electrical transcranial stimulus over the base of the skull. They hypothesised that the motor cortex inhibition observed was determined by activation of cerebellar structures. Nevertheless, the paradigm employed did not allow to exclude interference from extracerebellar structures due to spread of the electrical stimulus. In order to ascertain the role of the cerebellum in determining the modulation of the motor cortex excitability we examined, in 10 normal subjects and in 2 patients with unilateral cerebellar lesions, the effects of electrical stimuli over the base of the skull on the motor responses evoked by cortical magnetic stimulation. In both patients no inhibition of motor responses was present in the muscles ipsilateral to the lesion, whereas an inhibition, similar to that observed in controls, was evident on the opposite side. The present findings suggest the cerebellar origin of the motor effects seen after electrical stimulation of the base of the skull and further clarify the physiological cerebro-cerebellar interactions in man.

Action Potentials↗
PubMed1994

The role of upper limb somatosensory evoked potentials in the management of cervical spondylotic myelopathy: preliminary data.

We studied upper limb somatosensory evoked potentials (SEPs) in 11 patients with MRI and clinical evidence of cervical spondylotic myelopathy (CSM), before and after cervical open-door laminoplasty. SEP studies before surgery revealed two main types of abnormality, the first characterized by the isolated loss of the spinal N13 response, reflecting the dysfunction of dorsal horn cervical cells in 4 patients. The second combined abnormalities of both spinal N13 and scalp far-field P14 potential, suggesting the involvement of both dorsal horn cells and dorsal columns at the cervical level in 7 patients. After surgery, N13 recovered in 9 patients, while P14 abnormalities remained unchanged. Clinical recovery, evaluated by means of the Japanese Orthopaedic Association (JOA) disability scale, was accompanied by SEP improvement. Moreover, this improvement was more pronounced in patients with isolated loss of the N13 than in patients with combined abnormalities of the N13 and scalp P14 response. Our data strongly suggest that upper limb SEPs can be useful in monitoring the effectiveness of surgery, as well as in selecting before surgery patients who are likely to have a better postsurgical outcome.

Adult↗
PubMed1994

MHC class I, MHC class II and intercellular adhesion molecule-1 (ICAM-1) expression in inflammatory myopathies.

We investigated the relationship between the MHC-I, MHC-II and intercellular adhesion molecule-1 (ICAM-1) expression on myofibres and the presence of inflammatory cells in muscle specimens of 18 patients with inflammatory myopathies (nine polymyositis, seven dermatomyositis, two inclusion body myositis). We observed MHC-I expression in muscle fibres, infiltrating mononuclear cells and endothelial cells in every specimen. In seven patients, some muscle fibres were MHC-II-positive for the DR antigen, while the DP and DQ antigens were absent. ICAM-1 expression, detected in seven patients, was found in clusters of myofibres, associated with a marked MHC-I positivity and a widespread mononuclear infiltration. Most of the ICAM-1-positive fibres were regenerating fibres. Furthermore, some fibres expressed both ICAM-1 and DR antigens near infiltrating cells. This finding could support the hypothesis that myofibres may themselves be the site of autosensitization.

Antigens, CD↗
PubMed1993

Sensitivity and specificity of diagnostic criteria for conduction block in chronic inflammatory demyelinating polyneuropathy.

Detection of conduction block (CB) has important clinical implications because it suggests segmental demyelination potentially reversible following treatment. There are no universally accepted criteria to define CB. We tested the sensitivity of two diagnostic criteria of partial motor CB in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and hereditary motor-sensory neuropathy type I (HMSN I) which are thought to be the prototypes of segmental and uniform demyelination respectively. Criterion I requires > 20% drop in negative peak amplitude and area and < 15% change in duration between proximal and distal compound muscle action potentials (CMAPs). Criterion II requires > 50% drop in negative peak amplitude and area of proximal CMAP independently from temporal dispersion. Twenty-eight percent of CIDP nerves and 65% of CIDP patients had CB according to criterion I. However, 29% of nerves and 61% of patients with HMSN I also fulfilled the same criterion. Thirty-four percent of CIDP nerves and 78% of CIDP patients and none of HMSN I patients fulfilled criterion II. Criterion II has the same sensitivity as criterion I, but seems to be highly specific in diagnosis of the segmental demyelination characteristic of CIDP. Therefore this criterion should be employed, as the diagnostic tool of CB, in chronic neuropathies presenting high stimulation threshold and coexisting axonal loss.

Action Potentials↗
PubMed1992

Effects of surgical treatment in thymoma with myasthenia gravis: our experience in 103 patients.

A retrospective study of 103 thymectomies examines the effects of the integration of surgical and medical therapy in patients affected by myasthenia gravis accompanied by thymoma. An extended thymectomy via a median longitudinal sternotomy was used in 102 patients. The operative mortality was 4.85% (5/103 patients), the 10-year survival rate was 78% with a recurrence rate of 3.06% (3/98). Neoplastic infiltration and postoperative radiotherapy did not influence the survival rate. There was no correlation between a preoperative Osserman's class better than III and postoperative outcome. The improvement of medical treatment, and anaesthesiological and intensive care techniques resulted in a decrease of the operative mortality and long-term death rate during the last 10 years of our 20-year series. Extended thymectomy via sternotomy is the best intervention in patients with myasthenia gravis associated with thymoma judged by the low operative mortality and the favorable 10-year survival rates.

Adolescent↗
PubMed1992

Postural axial tremor in a patient with cerebellar atrophy.

A patient affected by low-frequency postural tremor of the trunk and limbs is reported. Apart from mild dysarthria and gait ataxia, no other neurological abnormalities were present. Cerebellar atrophy was demonstrated by means of magnetic resonance imaging. The tremor was associated with alternating activity in antagonistic muscles; it was triggered whenever a contraction of lumbar back extensor muscles occurred. Electrical stimulation of the cerebellum did not produce the normal suppression phases of motor responses evoked by a magnetic stimulation of the cerebral cortex.

Aged↗
PubMed1992

Giant axonal neuropathy: report on a case with focal fiber loss.

We report on a 5 1/2 year-old boy with chronic progressive polyneuropathy, ataxia, and pyramidal signs. His hair was not curled. Sural nerve biopsy disclosed many axons enlarged by accumulation of 10-nm neurofilaments and a marked variability in the number of myelinated fibers as well as in the amount of axonal enlargements among different fascicles. These findings and the electrophysiological data were consistent with a giant axonal polyneuropathy with a multifocal fiber loss.

Axons↗
PubMed1992

Cisplatin neuropathy: clinical course and neurophysiological findings.

Sixteen patients treated with cisplatin (CDDP) 40 mg/m2 on days 1-5 every 4 weeks for three courses (cumulative dose 600 mg/m2) were clinically and neurophysiologically tested before, during and 1, 3, 6, 9 and 12 months after CDDP administration. The first symptoms of polyneuropathy occurred in 4 of 9 patients after the second course (cumulative dose 400 mg/m2). One month after treatment 1 of 9 patients was asymptomatic, 5 complained of symptoms and 3 showed clinical and neurophysiological signs of polyneuropathy. Three months after CDDP all patients were affected. Clinical and neurophysiological signs of severity progression were noted up to 6 months after treatment with CDDP.

Action Potentials↗