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Biomedical subjects

F Pierelli

Publications and source records attributed to F Pierelli.

At least 37 records · Page 2Linked to original sources

Pattern visual evoked potentials and flash electroretinogram in clinically definite multiple sclerosis.

The authors have studied, by means of pattern visual evoked potential (VEP) and flash electroretinogram (ERG) recordings, a group of 15 patients affected by definite multiple sclerosis. All of the subjects examined presented a clinical history indicating involvement of the visual pathways; VEPs were altered in a high percentage of eyes examined (93.3%), while a lower percentage of abnormal ERGs was seen (20% of eyes examined). The only type of ERG alteration found consisted of a pathologic b wave voltage increase, observed mainly with red flash stimuli. This finding could be attributed to an involvement of centrifugal optic nerve fibers having inhibitory functions on retinal cells.

Adult

Subjective posttraumatic syndrome. A comparison of visual and brain stem auditory evoked responses.

Evoked responses testing including pattern visual evoked potentials (VEPs) and brain stem auditory evoked potentials (BAEPs) were performed in 57 subjects suffering from subjective posttraumatic syndrome (SPTS). 36 of them had loss of consciousness after head injury. Abnormalities were found in 12 subjects out of 57 (21%). In addition, the pathological findings by percentage were: 25% in subjects who had loss of consciousness after head injury (9 cases out of 36) and 14% in subjects without loss of consciousness (3 cases out of 21). Evoked response alterations were more frequent in subjects with frontal and/or occipital trauma; BAEP abnormalities were found to be more frequent than VEPs. Our findings suggest that evoked responses testing could be a useful noninvasive technique to evidence an organic dysfunction of CNS in some subjects with SPTS.

Adult

Electrophysiological measures (CNV--EEG) and nitrous oxide at low doses in man.

Nitrous oxide (N2O) is a widely used inhalational anesthetic gas, but its exact mode of action and its distribution in the CNS are not yet well known. The aim of this research was to study the effects of N2O at low doses (10 percent) in the CNS of humans. Five healthy volunteers were tested. Contingent Negative Variation (CNV), Reaction time (RT) and quantified EEG recordings were taken while subjects were breathing air and then N2O. A significant reduction of the post-imperative positive CNV components during N2O inhalation was observed; no changes in EEG power spectrum and RT values were seen. These results could be consistent with an early N2O interference with processes underlying CNV resolution, while vigilance and attention were still maintained.

Adult

Brain slow potentials and hypnosis.

Contingent negative variation behavior was studied in 12 voluntary normal subjects in basal conditions and in the hypnotic trance state under different emotional suggestions. A CNV voltage decrease and the appearance of a PINV were observed in the hypnotic state. Furthermore 12 nonhypnotizable control subjects were tested under the same experimental conditions and no CNV modification was found.

Adult

A longitudinal CNV study in a group of five bipolar cyclothymic patients.

The authors carried out a longitudinal study in five subjects with bipolar cyclothymic psychosis, recording contingent negative variations in the same patients in the different phases of illness and under normal clinical conditions. An average voltage decrease was found in the depressive phases and a more conspicuous decrease in the manic phases. Furthermore, an evident postimperative negative variation was present in four subjects during the manic phase. The authors set forth tentative psychological and neurophysiological interpretation of their results.

Adult

Antiepileptic effects of a calcium antagonist (nimodipine) on cefazolin-induced epileptogenic foci in rabbits.

The epileptogenic properties of cefazolin (CFZ) were utilized to induce an electrophysiological pattern of epilepsy in the rabbit. CFZ, cortically applied in different concentrations (2 or 4%), produced epileptic activity in a degree proportional to the concentration of the substance. In this experimental epilepsy model, we evaluated the effects of increasing doses (0.025, 0.05, and 0.1 mg/kg i.v.) of the calcium antagonist nimodipine (Bay e 9736). In the evaluation of nimodipine effects, the spike-and-wave burst frequency per minute was taken into account. These data were compared with those of placebo-treated (Bay e 9736 control test) control groups and statistically evaluated by two-tailed t test. In 2% CFZ-induced epilepsy, nimodipine at the 0.025- and 0.05-mg/kg doses did not produce significant changes in the EEG pattern. A statistically significant reduction (p less than 0.001) in epileptic activity was observed at the 0.1-mg/kg nimodipine dose. This reduction was seen first in the contralateral focus leads and persisted for the entire time of observation. In the more intense epileptic form (4% CFZ), nimodipine at the doses employed did not induce noteworthy EEG modifications. These data indicate that nimodipine exerts an antiepileptic effect. The possible mechanisms involved in this activity of a calcium antagonist are discussed.

Animals

Long-term EEG-video-audio monitoring: detection of partial epileptic seizures and psychogenic episodes by 24-hour EEG record review.

Twenty-seven patients with medically refractory paroxysmal disorders underwent EEG-video-audio (EVA) monitoring in an inpatient neurology-neurosurgery unit over 1-15 (mean 8.9) days. Fast visual review of all EEG records (5,784 h) and subsequent analysis of synchronized EVA patterns demonstrated a total of 208 partial epileptic seizures (ES) in 12 individuals and 87 psychogenic episodes (PE) in 15 subjects. Clinical ES lasted 83.3 s on the average and were most frequent from day 7 to 9 of monitoring (42.3%) and during sleep (56.4%). PE were longer in duration (mean 724.5 s), most numerous during the first 2 days of monitoring (41.4%), and occurred exclusively during wakefulness. Subjects with PE signaled (by pressing on a push button) more events (35.6%) than did the individuals with ES (27.9%). Multiple observers raised the proportion of alarms to 69.0% of PE compared to 39.9% of ES. Following the alarm, nurses reached the patients' bedside within a brief time (mean 22.2 s). To differentiate partial ES from PE or to establish the association of these disorders, EVA monitoring is best performed around the clock over a period of 1-2 weeks. The limited number of paroxysmal events, especially ES, signaled by the patients should be considered when designing studies of the effectiveness of pharmacologic, surgical, and other treatments.

Adolescent

Wolfram's syndrome: a clinical, diagnostic, and interpretative contribution.

Four cases (belonging to two different families) of Wolfram's syndrome (WS), a rare congenital disease characterized in its complete form by insulin-dependent diabetes mellitus, optic atrophy, diabetes insipidus, deafness, and dilation of the urinary tracts are presented, and a review of the literature is included. Three of four patients are characterized by HLA-DR2 haplotype, which is rare in IDDM. The neurodegenerative nature of some symptoms and the possible pathogenesis of diabetes mellitus connected with it are discussed.

Diabetes Mellitus, Type 1

[A case of central pontine myelinolysis: clinical and electrophysiologic findings].

We described a case of Central Pontine Myelinolysis, typical with regard to pathogenesis (excessive correction of hyponatremia), neuroanatomical damage revealed by imaging techniques (Magnetic Resonance Imaging) and clinical symptomatology. Serially performed BAEPs recordings during patient's hospitalization, showed interesting data on functional recovery which well correlate with the evolution of clinical symptomatology. These data strongly suggest the usefulness of such electrophysiological technique for a prognostic evaluation.

Brain Diseases

[Cluster headache: clinical and physiopathogenetic aspects].

The authors show the clinical characteristics of the cluster headache and consider the main physiopathogenetic hypothesis that could explain the polyhedric symptomatology of this kind of headache. They point out at first the hypothesis of an imbalance in the autonomic nervous system, sympathetic-parasympathetic, then they discuss about the theory of a disregulation of nociceptive system proposed by Sicuteri, at the end they hypothesize an alteration at the superior integrative level, probably the hypothalamic-limbic one.

Adult

Event-related potentials and autonomic functions.

The authors pointed out how some of the anatomic structures involved in the genesis of the event related potentials (ERPs) are also considered parts of the supranuclear regulation apparatus of the autonomic nervous system. Since there are evident functional similarities between some components of the ERPs and the orienting reflex--primitive form of attention--that is clearly associated with an autonomic activation, it could be interesting to evaluate the parameters of the ERPs in those experimental and clinical situations in which there is a functional involvement of the vegetative nervous system.

Autonomic Nervous System