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Biomedical subjects

P Pinelli

Publications and source records attributed to P Pinelli.

At least 37 records · Page 2Linked to original sources
PubMed1991

EMG evaluation of motor neuron sprouting in amyotrophic lateral sclerosis.

Collateral sprouting has been evaluated in amyotrophic lateral sclerosis (ALS) patients on the basis of: 1) Motor Unit action potential (M.U.A.P.) parameters evaluated by simultaneous EMG recordings using concentric needle electrodes and surface electrodes and 2) Motor Action Potential (M.A.P.) activated by graded electrical stimulation of nerve and recorded with the same electrodes. Mean values of duration and amplitude were calculated in 40 normal age-matched controls, 42 ALS patients in the early phase of the disease and in 5 muscles of three ALS patients during the whole course of the disease including the last paralytic phase. Percentage of M.U.A.P.s with linked potentials and highest amplitude was also calculated. The study confirms previous suggestions on collateral sprouting occurring in the early, middle and advanced phases of the disease and it shows, at variance with some recent claims, that it fails in the latest phase of paralysis.

Action Potentials↗
PubMed1990

Ataxia in myxoedema: a neurophysiological reassessment.

In a long-standing case of myxoedema with ataxia and dysarthria, neurophysiological investigations were carried out to assess how much of the ataxic dysbasic syndrome depended on the slowness of mechanical contraction and how much resulted from primary cerebellar involvement. It was observed that the Achilles reflexogram showed a marked prolongation of contraction and relaxation time and that in both quadriceps and triceps surae mechanical percussion induced a marked myxoedema and prolonged relaxation time. The EMG of these muscles during voluntary contraction and stopping reaction detected an excessive recruitment of the antagonistic muscles, starting without any abnormal delay, a finding at variance with a typical cerebellar pattern. Post-urographic analysis gave a pattern of oscillations still within the normal range. These findings suggest that the gait alterations of our patient depended on the increase in muscle contraction time and the consequent excessive recruitment of the antagonists.

Achilles Tendon↗
PubMed1990

Positive giant potentials: an electromyographic investigation.

Positive giant potentials (PGPs) consist of a peculiar EMG activity which is observed mostly in the large lower limb muscles, and mainly in men, either during the insertion of the needle electrode or during muscle contraction. PGPs have a shape similar to that of positive sharp waves, but with a larger amplitude (up to 25 mV). Their firing rate may reach 200 c/s. PGPs probably have no diagnostic significance since they are frequently observed in healthy individuals. They correspond to an insertional activity and should be recognized as such because they may be mistaken for giant motor unit potentials and thus be the source of diagnostic errors. The mechanism involved in the genesis of PGPs remains a matter of speculation.

Action Potentials↗
PubMed1990

Cryptogenic hemifacial spasm. A neurophysiological study.

Whether hemifacial spasm (HFS) is due to axono-axonal ephaptic transmission or to facial nucleus abnormal hyperexcitability remains controversial. The neurophysiological hallmark of HFS is the delayed response (DR). This response has an indirect pathway and thus a long latency. It is evoked A) as a distant response in muscles innervated by a facial branch other than the one stimulated, and B) in muscles innervated by the branch stimulated. In this work, 99 single all-or-none DRs of 24 cases of cryptogenic HFS were studied by threshold stimulation of a branch, or of the trunk, of the facial nerve. A) Eighty-eight distant DRs were studied. Fifty-four of them were frequently evoked as double discharges (DDs), or sometimes as multiple discharges, with a 3 to 7 ms interval. A collision technique, using paired stimuli, showed that the second discharge of 12 out of 20 DDs was accompanied by a back-wave due to a proximal ectopic re-excitation on the axon, or to the back-firing of an alpha cell (F-response), or to both. F-waves in HFS were more frequent than in normals or in other facial pathologies. B) Eleven DRs were recorded in muscles innervated by the facial branch stimulated. Some of them persisted when, using a stronger stimulus, the same all-or-none potential was also evoked as a direct response. In other cases both the direct response and the DR were evoked with identical stimulation threshold. The direct-indirect response interval of these 11 DRs was shorter than the normal M-F interval. These findings suggest that, in the case of HFS, axons are interconnected by uni- and bidirectional ephapses. Self-sustained repetitive firing in such a group of axons apparently results from re-excitations occurring both at the ephapse site and at the cellular level (F-responses). Spasm develops when several groups fire together. The changing excitability of the alpha cells modulates the importance of the phenomenon.

Adult↗
PubMed1989

Electromyographic assessment of spasticity.

We define the concept of muscle tone and describe the signs and symptoms of its alteration in spasticity. In assessing muscle tone it is important to consider all the inputs and outputs affecting it, using biomechanical-EMG techniques for measuring active tone. We list the various features of the myotatic and defence reflexes that are altered in spastics and analyze the altered parameters in relation to the tonic reflexes. The degree of displacement, the position from which it is initiated and the velocity of displacement constitute a specific, sensitive and reliable criterion. We report the results of a personal study of these reflexes and of the shortening reflexes.

Humans↗
PubMed1987

Antiprostatic effect of cimetidine in rats.

Administration of large doses of cimetidine for 45 days to rats decreases the weight of the prostate and seminal vesicles without affecting the testicles. The decrease in weight is due to a marked regression in the prostate of both epithelial and stromal tissue. Treatment with cimetidine also causes an increase in the plasma testosterone level without modifying the plasma values of LH and prolactin. The mechanism of action of cimetidine is discussed. In presence of high levels of testosterone, cimetidine depresses structures such as the prostate and seminal vesicles, which are sensitive to androgens, but does not depress the weight or change the histology profile of the testicles, which are also rich in androgen receptors. Perhaps cimetidine binds to androgen receptors differently in the prostate and in the testicles because of differences in receptor structure or more probably, cimetidine interacts with zinc metal ion essential to prostate growth and androgen action by lowering zinc prostatic levels and consequently depresses the prostatic weight.

Animals↗
PubMed1986

Inversion of T/TMP ratio in ALS: a specific finding?

Thiamine (T) and thiamine monophosphate (TMP) levels were determined by an electrophoretic fluorometric method in the CSF of patients with typical sporadic ALS (50 cases), in other motor neuron diseases (MND) (14 cases) and in patients with upper and/or lower motor neuron lesions of varying origin (disseminated sclerosis, polyneuropathy, spondylotic myelopathy). T/TMP ratio was greater than or equal to 1 in a high percentage of patients with typical sporadic ALS (94%), in 35.7% of cases with other MND, while it was below 1 in the all other patients. The decrease of TMP with the inversion of the T/TMP ratio is a finding highly specific to typical sporadic ALS.

Adult↗
PubMed1986

The identification of neuroapraxia, axonostenosis and trigger zone in facial nerve pathology.

The classical electromyographic investigations and simultaneous recordings of voluntary activity and M responses from muscles of both the upper and lower branch of the facial nerve were carried out in 5 patients with Bell's palsy. R1 responses were also recorded. All investigations were extended to the healthy side. With the aim of localizing the point of axonostenosis with axonal atrophy we investigated the following parameters: conduction velocity (c.v.) in the fallopian canal, c.v. in the external facial nerve, side difference of R1-M. In one case of amyotrophic lateral sclerosis with previous Bell's palsy signs of collateral sprouting and of ephaptic transmission were detected.

Adult↗
PubMed1985

Monotherapy and polytherapy for intractable epilepsies.

A retrospective survey on 66 adults with epilepsy who received multiple drug therapy after the failure of single drugs showed: a reduction of seizure frequency of 75% or more in 16.5%, no change in 67% and an increase in seizure frequency of 100% or more in 16.5%. Multiple drug therapy is of limited value in severe epilepsies.

Anti-Anxiety Agents↗
PubMed1982

Lymphocyte populations in patients with myasthenia gravis. Influence of thymectomy and immunosuppressive drugs.

The T/B peripheral blood lymphocyte ratio was evaluated in 51 patients with myasthenia gravis by means of the rosette test and HTLA. Total T cells and T gamma and Tmu were decreased while B lymphocytes were increased. E-active rosettes were also above the normal range. The previous thymectomy and/or immunosuppressive treatment restored the T lymphocytes identified by HTLA to normal range while those identified by E rosettes were still reduced. This difference may be due to the different stages of T lymphocyte maturation.

Adolescent↗
PubMed1982

Isoprinosine in multiple sclerosis treatment: a preliminary study.

Isoprinosine, a drug enhancing the cellular immunity, was administered to 11 patients with multiple sclerosis (MS) for a period of 60 days. Kurtzke's Disability Status Scale was evaluated in all the patients before the starting of the therapy and after 60 days and after 14 months of follow-up. 11 MS patients were taken as a control group and were treated with prednisone for the same period of time. No significant difference in the clinical course of the disease between the two groups of patients after the therapeutical trial was observed. CSF examination showed IgG oligoclonal bands in all the cases; no modification of the CSF IgG profile was found after the therapy in those patients in whom the lumbar puncture was performed after the follow-up period.

Adult↗
PubMed1982

Neuromuscular diseases associated with benign monoclonal gammopathy. Study of CSF and serum proteins by isoelectric focusing.

In over 1200 cases examined by isoelectric focusing of CSF and serum proteins, 4 patients had benign monoclonal gammopathy. These patients were affected by amyotrophic lateral sclerosis of bulbar onset, sensitive neuropathy of Thevenard type, myasthenia gravis, and limb-girdle muscular dystrophy, respectively. The difficulty to relate the differences in the clinical features of these cases to a common physiopathological mechanism and the incidence of this finding (0.4% in 873 cases ranging from 21-60 years of age) do not seem to suggest any pathogenetic relationship between benign monoclonal gammopathy and the different neurological disorders encountered in these patients.

Adult↗