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Biomedical subjects

L Murri

Publications and source records attributed to L Murri.

At least 91 records · Page 5Linked to original sources
PubMed1997

Alteration of cardiac function in patients with temporal lobe epilepsy: different roles of EEG-ECG monitoring and spectral analysis of RR variability.

PURPOSE: Because several reports have described the relation between epilepsy and cardiac arrhythmias and suggest that changes in autonomic neural control of the heart could be involved in the pathogenesis of sudden unexplained death in patients with epilepsy, the aim of this study was to evaluate cardiac function in patients with temporal lobe epilepsy. METHODS: Sixty-five patients with epilepsy were evaluated by simultaneous ambulatory 24-h EEG-ECG monitoring, and in 30 of these, power spectral analysis of relative-risk (RR) variability also was carried out, both in the supine position and in a passive tilt position at 60 degrees. The power spectrum of RR variability, the two major spectral components detectable at low frequency (LF) and at high frequency (HF), respectively, and the LF/HF ratio were calculated. RESULTS: By EEG-ECG monitoring, we recorded six partial seizures, and in four cases, discharges were associated with sinus tachycardia. However, interictally the occurrence of ventricular and supraventricular arrhythmias was not different from that in normal subjects. The spectral analysis of RR variability, on the other hand, demonstrated in patients with epilepsy a significant decrease in the total RR variability and in both of its components (LF and HF) in the supine position, and of the LF/HF ratio in orthostatic position. CONCLUSIONS: These findings suggest that the spectral analysis of RR variability may detect disorders of autonomic cardiac control in patients with epilepsy, even in the absence of abnormal findings during ECG monitoring. This alteration, which is more severe in cases with right EEG focus, could play a role in the pathogenesis of cardiac arrhythmias.

Arrhythmias, Cardiac↗
PubMed1997

A quantitative study of daytime sleepiness induced by carbamazepine and add-on vigabatrin in epileptic patients.

INTRODUCTION: The clinical relevance of daytime sleepiness associated with carbamazepine (CBZ) and vigabatrin (VGB) was objectively assessed by the multiple sleep latency test (MSLT) and nocturnal sleep recordings. MATERIAL AND METHODS: Twenty-six patients with partial epilepsy and mean monthly seizure frequency of 4, aged 18 to 48 years, receiving chronic monotherapy with CBZ and subsequent VGB addition for 2 months (14 patients), were compared with a group of healthy subjects. Subjective daytime sleepiness was complained by 13 patients on CBZ monotherapy and 9 patients during VGB add-on treatment. RESULTS: No differences in nocturnal sleep parameters, but significantly shorter daytime sleep latencies at the MSLT, were detected in CBZ-treated patients as compared with healthy controls. Addition of VGB therapy did not further enhance objective daytime sleepiness. CONCLUSION: Some sleepiness occurs in chronically CBZ-treated epileptic patients, which can be objectively measured by the MSLT, but it is not aggravated by add-on VGB.

Adolescent↗
PubMed1997

Carotid plaque features on angiography and asymptomatic cerebral microembolism.

We studied 110 carotid arteries of 55 patients with unilateral or bilateral carotid stenosis diagnosed with selective angiography, by using Transcranial Doppler to detect high intensity transient signals (HITS) in the middle cerebral arteries (MCAs). HITS identified as embolic signals were prevalent (P < 0.05) in the MCAs on the same side as severe (70-99%) stenosis (22 of 51 = 43.1%) compared to moderate (30-69%) stenosis (5 of 37 = 13.5%). No HITS were observed in the MCA on the same side as normal control carotid arteries (n = 17) [occluded arteries (n = 5) were not considered]. HITS were more prevalent (P < 0.05) in the MCAs on the same side as ulcerated plaques (14 of 23 = 60.9%) compared to non-ulcerated plaques (13 of 65 = 20%), and all moderate stenoses producing HITS presented ulceration of the plaque. Ulcerated plaque groups showed a higher mean number of HITS than non-ulcerated plaque groups and no significant difference was noted between moderate and severe stenosis, between superficial or deep ulcerations and between ulcerations with flap or without flap. Therefore, severe carotid stenosis and moderate stenosis with plaque ulceration result in angiographic findings most frequently associated with HITS. Further studies are necessary to evaluate the clinical significance of this finding.

Aged↗
PubMed1997

Silent cerebral microembolism in asymptomatic and symptomatic carotid artery stenoses of low and high degree.

124 carotid arteries of 62 patients with unilateral or bilateral carotid stenosis proven by selective angiography were investigated by transcranial Doppler to detect high-intensity transient signals (HITS) in the middle cerebral arteries (MCAs). HITS identified as embolic signals were detected in 29 of 124 (23.3%) MCAs and in all cases were asymptomatic. HITS were more common in the MCAs on the same side as high-degree (> 70%) carotid stenoses (24 of 57 = 42.2%) compared with low-degree (< 70%) carotid stenoses (5 of 28 = 17.9%, p < 0.05). No HITS were detected in the MCAs on the same side as normal (24) and occluded (15) carotid arteries. About the clinical features related to the stenoses, HITS were detected with a nonsignificant prevalence in the MCAs on the same side as symptomatic stenoses (16 of 43 = 37.2%) compared with asymptomatic stenoses (13 of 42 = 30.9%) and a relationship between HITS number and time elapsed from symptoms was observed. All symptomatic carotid stenoses > 70% (33) underwent endarterectomy and none of them showed HITS after surgical treatment. These results encourage the feasibility of prognostic studies to evaluate the clinical significance of embolic signals and suggest that silent microembolism could be helpful in selecting a high-risk group of asymptomatic or < 70% carotid stenoses for endarterectomy.

Aged↗
PubMed1997

Catamenial epilepsy, progesterone and its metabolites.

This study was undertaken to determine plasma allopregnanolone (3alpha-hydroxy-5alpha-pregnan-20-one, A-PREG) and pregnanolone (3alpha-hydroxy-5beta-pregnan-20-one, PREG) concentrations in the luteal phase (22nd to 24th day of the ovarian cycle) in 15 women with partial epilepsy and catamenial exacerbation of the seizures in the intercritical phase and in 15 healthy women matched for age in order to determine if an impaired metabolism of 3alpha-hydroxymetabolites of progesterone (P) occurs in this convulsive disorder. No significant differences between the two groups were found with respect to the mean plasmatic A-PREG and PREG levels. A significant correlation was found instead between P and A-PREG or PREG concentrations.

Adolescent↗
PubMed1997

Clinical and biochemical features of muscle dysfunction in subclinical hypothyroidism.

Alterations in muscle structure and function have been reported in overt hypothyroidism, with decreased activity of enzymes involved in anaerobic and oxidative glucose metabolism. To test whether similar changes in muscle energy metabolism are present in subclinical hypothyroidism (sHT), we studied 12 patients with sHT who complained of mild neuromuscular symptoms. The control group included 10 sex- and age-matched healthy volunteers. Skeletal muscle lactate and pyruvate production were determined in the resting state and during dynamic arm exercise. During exercise, blood lactate was significantly higher in sHT patients than in controls from the third exercise step onward (P = 0.02 at 30%, p = 0.008 at 40%, and P = 0.002 at 50% of maximal voluntary contraction). Moreover, the mean increment in blood lactate during exercise was positively related (r2 = 0.44; P = 0.02) to the duration of sHT, but not to serum levels of TSH, free T3, or free T4. No significant difference was found in blood pyruvate concentrations between the two groups at baseline or during exercise. Thus, the lactate/pyruvate ratio curve paralleled the lactate curve in patients as well as controls. We conclude that muscle energy metabolism is impaired in sHT in rough proportion to the known duration of the disease. Early L-T4 therapy may be useful not only to provide specific treatment for such metabolic changes, but also to avoid progression to frank hypothyroidism.

Adolescent↗
PubMed1997

Clozapine in Parkinson's disease tremor. Effects of acute and chronic administration.

The effects of the acute administration of clozapine on parkinsonian mixed tremor (i.e., resting and postural tremors) were evaluated to establish clozapine's predictive value for long-term response and to determine if there is a difference in the pharmacologic responses of the two tremors. We also investigated the correlation between reduction of tremor and induction of sedation after acute and chronic administration of clozapine. Clozapine (12.5 mg) or placebo were administered po in a double-blind manner to 17 PD patients with mixed L-dopa-resistant tremors. Two patients did not reach 50% improvement and were considered nonresponders. The remaining 15 patients reported moderate to marked reduction of tremor. Responsive patients in the acute test moved on to a long-term, open clozapine add-on study receiving an average daily dose +/- SD of 45 +/- 9.6 mg for a period of 15.5 +/- 8.3 months. A significant reduction of both resting (p < 0.05) and postural (p < 0.05) tremors was observed under clozapine from the first week of treatment through the entire period of the study. There was no statistically significantly difference between the degree of improvement for resting and postural tremors after either single or chronic clozapine administration. Sedation was the only side effect reported after clozapine; however, the time courses of sedation and tremor reduction did not coincide in the acute or in the chronic experimental paradigm, where it decreased considerably in a few weeks in all patients. During long-term clozapine treatment, neither systemic side effects nor worsening of motor disability scores were noted. Thus we wish to propose an acute test or a therapeutic attempt, or both, with clozapine before defining a case of mixed parkinsonian tremor as resistant tremor and therefore resorting to a neurosurgical approach.

Aged↗
PubMed1997

Central motor pathway evaluation using magnetic coil stimulation in hereditary motor and sensory neuropathy type I (HMSN type I, Charcot-Marie-Tooth disease).

Central Motor Conduction Time (CMCT) was investigated in 18 patients (5 m, 13 f; age range: 11-69 yrs) with clinical and electrophysiological features of HMSN type I, using Magnetic Coil (MC) stimulation. No one exhibited clinically pyramidal signs. Brain stimulation Motor Evoked Potentials (MEPs), recorded monolaterally from the left abductor digiti minimi (ADM) and tibialis anterior (TA) muscles, were evoked in all patients from upper extremities and absent in 11.1% from lower limbs. Total Motor Conduction Time (TMCT), as well as Peripheral Motor Conduction Time estimated by either magnetic nerve root stimulation (mag-PMCT) or F-wave latency values (F-PMCT), were markedly delayed in all patients. Central Motor Conduction Time was calculated by subtracting both the latency of mag-PMCT (mag-CMCT) and F-PMCT (F-CMCT) from that one obtained by cortical stimulation. F-CMCT was abnormal in 22.2% in upper extremities and in 27.8% patients from lower extremities, whereas mag-CMCT in 22.2% from ADM muscles and in 33.3% from TA muscles. Furthermore, CMCT to both methods was not possible to evaluate in 5.6% from upper and lower extremities and following magnetic root stimulation in 11.1% from lower limbs. These findings prove lower motor neuron involvement, in agreement with electroneurographic data, and suggest a possible central motor pathways impairment, even in patients without any clinical evidence, but they cannot explain which is the underlying pathophysiological mechanism, a true upper motor neuron involvement or an abnormal spinal motor neuron excitability.

Adolescent↗
PubMed1997

Functional uncertainty, aging and memory processes during sleep.

Disorganized sleep patterns, can be found both during normal development and in pathological conditions. Aging could also be accompanied by a disorganization of the night sleep episode; sleep could be interrupted by spontaneous awakening, sleep cycle could be shortened or incomplete, sleep states modified. These patterns suggest an inability to sustain a stable condition, i.e. a condition of functional uncertainty. Biological and cognitive implications of functional uncertainty conditions are discussed. In particular, the hypothesis has been put forward that disturbances of sleep could have a detrimental role on memory. Recent results obtained in our lab support this hypothesis: recall is correlated with NREM-REM cycles proportion. Future research should ascertain the role of the functional uncertainty with respect to the kind of memory being involved during sleep, and establish how much and for which cognitive processes (including those involved in dream production) the inability to sustain a steady condition impairs the functioning during sleep. The duration of the functional uncertainty condition is also important. The long-term study of the link between functional uncertainty and cognitive resources, could be important for the understanding of the night life and for an adequate treatment of patients.

Adult↗
PubMed1996

Circulating levels of anticonvulsant metabolites of progesterone in women with partial epilepsy in the intercritical phase.

The 3alpha-hydroxy metabolites of progesterone (P), 3alpha-hydroxy-5alpha-pregnan-20-one (allopregnanolone, A-PREG) and 3alpha-hydroxy-5beta-pregnan-20-one (pregnanolone, PREG), have been found to be among the most potent ligands of gamma-aminobutyric (GABA)-A receptors; in experimental animals, they have been found to have anxiolytic, hypnotic and anticonvulsant effects. Similar to those of the benzodiazepines and barbiturates that interact with GABA-A receptors. The present study was undertaken to determine plasma A-PREG and PREG concentrations in the luteal phase in women with partial epilepsy, in order to determine if an impaired metabolism of P occurs in this convulsive disorder. We measured plasma P, A-PREG and PREG levels in 15 women with partial epilepsy in the intercritical phase, and in 15 age-matched healthy women, during the luteal phase of the ovarian cycle (22nd-24th day). The mean plasma +/- S.E. A-PREG levels (three blood samples) were 0.7 +/- 0.6 ng/ml in the epileptic women and 0.5 +/- 0.2 ng/ml in controls, with no significant difference between the two groups (p = NS); the PREG levels were also similar (1.4 +/- 1 ng/ml and 1 +/- 1.1 ng/ml, respectively: p = NS). A significant correlation was found between P levels and both A-PREG and PREG levels (r = 0.72, p < 0.001 and r = 0.79, p < 0.001, respectively). There were no significant differences between the two groups in terms of serum adrenocorticotropic hormone, cortisol, dihydroepiandrosterone-sulfate, follicle stimulating hormone, prolactin, luteinizing hormone or estradiol levels.

Adolescent↗
PubMed1996

Cryoglobulinemic peripheral neuropathy: neurophysiologic evaluation in twenty-two patients.

The aim of this study was to evaluate the frequency and degree of peripheral neuropathy in 22 consecutive patients with mixed cryoglobulinemia, whether symptom-free or with subjective neurological symptoms. Electrophysiological investigations were carried out and a biopsy of the sural nerve was performed in six patients. Peripheral neuropathy of the lower limbs was demonstrated, which was mostly sensory and light or moderate in 86% of cases (19 patients). F-Wave and H-reflex recordings were found to be the most reliable methods; in 77% of cases, they were abnormal (17 patients). Using somatosensory evoked potentials, we were able to exclude simultaneous central nervous system involvement in 10 patients.

Adult↗
PubMed1996

Posatirelin in the treatment of vascular dementia: a double-blind multicentre study vs placebo.

INTRODUCTION: The usefulness of posatirelin (L-pyro-2-aminoadipyl-L-leucyl-L-prolinamide), a synthetic peptide having modulatory activity on the monoaminergic and cholinergic systems and neurotrophic effects, was evaluated in vascular dementia. PATIENTS AND METHODS: A multicentre, parallel groups, double-blind clinical study vs placebo was carried out with patients suffering from probable vascular dementia according to the NINDS-AIREN criteria. The study consisted of a two-week run-in of a once daily, orally administered, placebo phase, followed by 12 weeks of intramuscular treatment with posatirelin 10 mg/ml or placebo given once a day and a follow-up after one month's withdrawal. Efficacy was assessed using the Gottfries-Bråne-Steen (GBS) Rating Scale for dementia, the Randt Memory Test and the Toulouse-Piéron Attention Test. Data were evaluated using analysis of variance and covariance. RESULTS: As regards GBS scores, patients treated with posatirelin showed a significant improvement in intellectual performance, in orientation, motivation and memory as compared to controls. The improvement of memory performance was also confirmed by the acquisition score and memory index of the Randt Memory Test. At the end of the follow-up period the differences between treatments were still maintained. Tolerability was good. CONCLUSIONS: The significant improvement observed in cognitive functions, attention and motivation of demented patients treated with posatirelin suggests the potential usefulness of this drug in vascular dementia. Furthermore, the presence of a long-lasting effect after drug withdrawal suggests the possibility of administering the drug cyclically.

Aged↗
PubMed1996

Transcranial Doppler assessment of cerebral flow velocity at rest and during voluntary movements in young and elderly healthy subjects.

Fifty-five healthy volunteers (thirty young and twenty-five elderly), all of them right-handed, were investigated by Transcranial Doppler monitoring mean flow velocity on the right and left middle cerebral artery at rest, during a motor task performed by the hand and in the following rest condition. In all cases the motor task induced an increase in bilateral mean flow velocity, but significantly greater on the opposite side middle cerebral artery in the task. The percentage increase in mean flow velocity compared to the rest condition observed during the motor task performed by the opposite side hand to the artery investigated was significantly greater in the young than the elderly. Moreover, in the young, this increase showed a slight prevalence during the left middle cerebral artery assessment relating to right hand preference. Furthermore, elderly subjects achieved the greatest mean flow velocity percentage increase compared to rest condition later than young subjects and returned to basal values more slowly.

Adult↗
PubMed1995

Evaluation of olfactory function by topographic EEG analysis in patients with Parkinson's disease.

Olfactory function impairment has been observed in patients with idiopathic Parkinson's disease (PD) using psychophysical procedures. In this study, an electrophysiological technique based on spectral analysis and topographic EEG mapping was used to evaluate EEG arousal response to olfactory stimulation in ten normal subjects and ten PD patients in stage II according to Hoehn and Yahr's scale, all of whom had akinetic-rigid syndrome and were receiving chronic L-Dopa therapy. Olfactory function was stimulated using diluted benzaldehyde by means of an apparatus set up in our laboratory. Spontaneous and post-olfactory stimulus EEGs were recorded from 20 electrodes placed upon the scalp according to the Int. 10-20 System. Total EEG power (from 0.5 to 19.5 Hz) was evaluated over 10 sec. artefact-free epochs. An olfactory arousal reaction was detected in nine of the ten PD patients and was characterised by a significant decrease in total power similar to that observed in all of the 10 normal subjects; these variations in EEG were found in all but the anterior regions of the scalp. The use of this technique does not seem to reveal any clear alteration in the olfactory function of PD patients.

Aged↗
PubMed1995

Vigabatrin as first add-on treatment in carbamazepine-resistant epilepsy patients.

Numerous clinical reports and several controlled clinical trials have confirmed that vigabatrin is both effective and well-tolerated as an add-on treatment for patients with drug-resistant epilepsy. This report presents the results of a study of 40 patients (22 women and 18 men), aged 19-60 years (mean 37 years), with partial seizures (with or without secondary generalization) and receiving carbamazepine, 600-1800 mg/day. Vigabatrin was given as first add-on drug at a dose of 2-3 g/day for an average of 6 months, in order to assess the clinical response before considering other anti-epilepsy drugs. There was a significant decrease in seizure frequency, from a median of 13 seizures/month at baseline, to 3 seizures/month during the last month on vigabatrin (p < 0.01). Seven patients became seizure-free (17.5%). The most common adverse events experienced during the study were drowsiness, diplopia/blurred vision, and were already present before vigabatrin treatment. In conclusion, vigabatrin is effective as a first add-on therapy for partial epilepsy, refractory to carbamazepine monotherapy, and appears to be a worthy clinical alternative to other drug combinations.

Adult↗
PubMed1994

Quantitative description of EEG periodicities during stationary sleep stages.

A quantitative method was applied in order to assess variations in EEG activities during sleep. Three classes of variations were distinguished: variations connected with sleep-stage changes (class 1), higher-frequency variations described by the envelope of frequency-band activities (class 2), intermediate-frequency variations, corresponding to periods from 4 to 120 s (class 3). For each class, parameters characterizing the frequency spectra were computed. These parameters were mathematically simple and clear in their meaning, since they measured power, modulation index and mean squared frequency. A statistical comparison of the mean values of the parameters during different sleep stages evidenced a certain number of significant shifts in each of the three classes. The most important class-1 and class-2 variations were described by our parameters with high levels of significance. The results obtained for class 3 were in agreement with visual observations reported in the literature, such as the progressive increase in the interval between successive arousals from sleep onset to Stage 4 and the frequent occurrence of cyclic alternating patterns during Stage 2 epochs immediately preceding REM sleep.

Journal Article↗