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Biomedical subjects

M Lo Monaco

Publications and source records attributed to M Lo Monaco.

At least 37 records · Page 2Linked to original sources
PubMed1993

Quantitative EMG findings at different force levels in patients with myasthenia gravis.

Quantitative electromyography, comprising manual motor unit potential analysis at weak effort and turns/amplitude analysis at 30% of maximum force were performed in the brachial biceps muscle of 17 patients with myasthenia gravis (MG). Findings simulating myopathic and less often neurogenic changes were observed in seven out of 17 patients, suggesting that the myasthenic muscle may have random block of muscle fibres, functional block of the main part or whole motor units or a changed recruitment pattern. In addition, turns/amplitude analysis was performed at low force levels (10% of maximum force) both before and after a provocative manoeuvre consisting of a maximum effort sustained for 1 min, and at maximum force at the beginning and at the end of the provocation itself. Turns/amplitude analysis at low force failed to differentiate MG patients from controls. The relative change of ratio of turns to mean amplitude calculated from 10% to maximum force (at the beginning of the provocative manoeuvre) was increased in seven out of eight patients compared to the controls. This last finding seems to be useful in differentiating MG patients from patients with myopathy.

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

Long-term results of corticosteroid therapy in patients with myasthenia gravis.

We studied the long-term outcome of prednisone therapy in 104 patients with myasthenia gravis (MG). At the end of the follow-up period, good therapeutic results were recorded in 85 patients (81.7%), poor results in 13 (12.5%) and no significant change of MG status in 6 (5.8%). We found a correlation between the duration of treatment and the incidence of steroid side effects. The presence of thymoma and severe forms of MG were associated with relapsing disease requiring prolonged corticosteroid regimens. The age at the start of therapy did not influence significantly the response to treatment.

Adult↗
PubMed1991

Accuracy of reinnervation by peripheral nerve axons regenerating across a 10-mm gap within an impermeable chamber.

The axon regeneration following a peripheral nerve injury often fails to restore a complete functional recovery. One of the causes of this unsatisfactory result has been attributed to regrowth of regenerating fibers to inappropriate peripheral targets. The accuracy of reinnervation by axons regenerating across a 10-mm gap within an impermeable chamber has been studied by using a sequential retrograde double-labeling technique. Despite the long gap between the nerve stumps, at 4 weeks a mean of 30.5% of the regenerating axons can reinnervate the original muscular area. These data confirm previous studies in which a preferential reinnervation is reported not to be absolutely dependent on the axon's mechanical alignment.

Action Potentials↗
PubMed1990

Early-onset myasthenia gravis: clinical characteristics and response to therapy.

We studied 59 children with myasthenia gravis (MG). Disease onset was pre-pubertal in 26 patients and post-pubertal in 33. The male to female ratio was 0.62 in the early- and 0.17 in the late-onset groups. The frequency of ocular MG was higher in patients with prepubertal onset. Patients with generalized MG generally showed a good response to thymectomy and corticosteroid therapy proved effective with no major side-effects. In our experience early-onset MG has the same course as in adult life. We recommend thymectomy for generalized disease in childhood, except in very young children on account of possible long-term effects on immunological development. Immunosuppressive therapy should be considered in severely affected patients who do not respond adequately to other therapies.

Adolescent↗
PubMed1990

Somatosensory evoked potentials in a case of neurosyphilis.

Here we report median and common peroneal nerve SEPs in a patient with tabes dorsalis. SEPs were within normal limits following median nerve stimulation, but of prolonged latency for common peroneal nerve. This was in keeping with clinical findings of posterior column involvement confined to the lumbosacral tract and with pathological features of tabetic neurosyphilis.

Adult↗
PubMed1990

[The effects of nitrous oxide on evoked potentials recorded during enflurane and isoflurane anesthesia].

The effects on median nerve somatosensory evoked potentials produced by nitrous-oxide (67%) were studied in 20 patients undergoing elective surgery under enflurane or isoflurane anaesthesia. This study demonstrates that nitrous-oxide does not significantly modify spinal (N13) and cortical (N20) component latencies nor central conduction time. The addition of nitrous-oxide to enflurane or isoflurane (up to 1 MAC) causes a significant reduction of N20 amplitude.

Adult↗
PubMed1989

Lephetamine abuse and dependence: clinical effects and withdrawal syndrome.

Lephetamine (L-SPA) is a compound with central analgesic and anti-inflammatory action, recently reported to be abused in Italy. In this study, cases of L-SPA abuse were recorded. The survey included 15 patients who were assessed for effects caused by using L-SPA and induced by withdrawal. Moreover L-SPA was administered to 15 volunteers. L-SPA displayed effects partly similar to opiates and its withdrawal caused both subjective and objective symptoms. It is concluded that L-SPA exhibits abuse liability and dependence potential of a certain degree.

Female↗
PubMed1988

Ocular myasthenia: diagnostic and therapeutic problems.

Forty-eight patients with purely ocular myasthenia were studied. Tensilon test was positive in 46 patients (95%); decremental response from limb muscles was present in 24 patients (50%); anti-AChR antibodies were detected in 20 patients of 44 (45.5%). Twenty-two patients underwent thymectomy, 18 were given corticosteroids, 42 received AChE drugs. At the end of the observation period, 8% of the patients were in remission, 67% were improved, 25% were unchanged. In our experience, the diagnosis of ocular myasthenia relies mainly on clinical data; AChE drugs are not very effective in extrinsic ocular muscles; indications for thymectomy should be restricted to thymoma cases and, perhaps, to patients in the early stages of the disease, within the first year of onset; corticosteroids are effective in most cases, but relapses after withdrawal are not uncommon.

Adolescent↗
PubMed1987

Motor and sensory conduction along the posterior interosseous nerve.

The posterior interosseous nerve (PIN) is the main distal branch of the radial nerve. It innervates most of the extensor muscles of the forearm and contains deep sensory fibres directed to the ligaments and joints of the wrist. The presence of deep sensory fibres allow measurement of sensory conduction (SCV) other than motor nerve conduction velocity (MCV) along this nerve. Normal values of motor and sensory conduction along the terminal branches of the radial nerve distal to the elbow are reported. The results accord well with data previously reported.

Action Potentials↗
PubMed1985

Turns analysis (peak ratio) in EMG using the mean amplitude as a substitute of force measurement.

Several modifications of turns and mean amplitude analysis of the electrical activity of muscles have been suggested to avoid measurement of force. Previously we have shown that these modifications may overlook abnormalities if the analysis is performed at high force. A new modification is suggested: analysing the maximal value of the ratio of turns to mean amplitude (peak ratio), using the mean amplitude as an indication of force. It has been applied to a material in which the force was measured. The peak ratio was increased in 82% of 17 patients with myopathy and decreased in 36% of 14 patients with neurogenic disorders.

Adolescent↗
PubMed1985

Pattern of electrical activity and force in normal and pathological muscle: S-index of turns and amplitude.

Cenkovich et al. (1982) found that a rotated hyperbolic curve fitted the relationship between the logarithm of cumulative amplitude (log A) and the logarithm of turns (log T). They found the intercept of the hyperbola (S-index) to be independent of force and suggested to use the S-index without measurement of the force as a diagnostic criterion. We have applied this modification of the method to our material previously published. In controls we found a slight increase in S-index with increasing force. The S-index was often increased in patients with myopathy and decreased in patients with neurogenic disorders, mostly at low to moderate force. The S-index was not better in discriminating patients from controls than the ratio of turns to mean amplitude.

Adolescent↗
PubMed1984

Integrated electrical activity and number of zero crossings during a gradual increase in muscle force in patients with neuromuscular diseases.

In the brachial biceps muscle of 17 patients with myopathy and of 14 patients with neurogenic disorders the integrated electrical activity and number of zero crossings per unit time were analysed in 3 sites of each muscle every 100 msec during a gradual increase in force from zero to maximum within 10 sec. The analysis of integrated electrical activity could not discriminate between patients with myopathy and patients with neurogenic disorders. The slope of the linear relation between the square root of integrated electrical activity and force expressed in kilograms was increased in 44% of the patients with myopathy and in 64% of the patients with neurogenic disorders. The increase in slope may be due to increase in the ratio of electrical activity and force of individual motor units. The integrated electrical activity related to a force of 40% of maximum was decreased in about two-thirds of patients with myopathy and in about half of the patients with neurogenic disorders. This decrease in integrated electrical activity may be due to random loss of muscle fibres or to loss of whole motor units respectively. The integrated electrical activity was linearly related to mean amplitude between potential reversals per unit time (turns). The number of zero crossings was increased in 29% of the patients with myopathy and decreased in 70% of the patients with neurogenic disorders at a force of 30% of maximum. The number of zero crossings was linearly related to turns.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1984

Processing of electrical activity in human muscle during a gradual increase in force.

The integrated electrical activity, the number of zero crossings and the number of turns, the mean amplitude and the ratio between them, of the electrical activity were compared in the brachial biceps muscle and the anterior tibial muscle of 20 controls. The electrical activity and force were analysed every 100 msec during a gradual increase in force from zero to maximum within 10 sec. The square root of integrated electrical activity increased linearly with increasing force. The slope of this relation was inversely related to maximum force when the increasing force was expressed in kilograms. The number of zero crossings per unit time increased with increasing force up to 40-60% of maximum force after which it remained constant. Comparison of 100 microV and 50 microV level detections suggested that there is a cancellation of small spike components in the electrical activity during higher force. The square root of integrated electrical activity was linearly related to mean amplitude between turns and the number of zero crossings was linearly related to the number of turns. In conclusion the information obtained by analysis of integrated activity and number of zero crossings is probably also obtained by number of turns and mean amplitude analysis.

Adolescent↗
PubMed1984

Electrical muscle activity during a gradual increase in force in patients with neuromuscular diseases.

The electrical activity of the brachial biceps muscle from 31 patients with neuromuscular diseases were quantified during a gradual increase in force from zero to maximum within 10 sec. In patients with myopathy the ratio of potential reversals per 100 msec (turns) to mean amplitude was increased more often at 10% and 20% of maximum force than at greater force (i.e., in four-fifths of the patients). Similarly, the mean amplitude as a function of turns was more diagnostic at low than at high force, possibly due to an affection of low threshold motor units. In 14 patients with neurogenic disorders turns was decreased in nearly two-thirds of the patients at a force of 20% and 30% of maximum. In muscles where the force is easily determined it is suggested to quantitate the electrical activity during constant forces of 10% and 30% of maximum. In muscles where the force is difficult to determine the analysis of the ratio of turns to mean amplitude should be performed when motor unit potentials begin to interfere.

Adult↗
PubMed1983

Conduction studies along the accessory, long thoracic, dorsal scapular, and thoracodorsal nerves.

Latencies to the trapezius (upper and lower portion), serratus anterior, latissimus dorsi and rhomboid muscles were evaluated in 66 subjects. There was a significant relation between latencies and conduction distances to the rhomboid, to the trapezius and to the serraturs anterior muscles but not to the latissimus dorsi muscle, probably due to differences in the organization of the endplate regions in the muscles in question.

Accessory Nerve↗
PubMed1982

When is there a full recovery for a myasthenia gravis patient?

A myasthenia gravis (MG) patient who seems to have recovered can later have recurrence of myasthenic signs. Clearly clinical remission does not always correspond to the normalization of all the factors involved in the pathogenesis of the disease. In ten patients who had apparently recovered from MG, electromyographic tests of repetitive supramaximal stimulation were performed and the anti-acetylcholine receptor (anti-AChR) antibody was assessed. In two of the ten patients all these tests were normal, thus showing lack of electromyographic myasthenic fatigability and the absence of circulating anti-AChR antibodies. Our hypothesis is that for these two subjects the risk of a recurrence of MG is lower than for the others.

Adolescent↗