PubMed Health⌕ Search

Biomedical subjects

C Munari

Publications and source records attributed to C Munari.

At least 37 records · Page 2Linked to original sources
PubMed1997

Activation of brain nitric oxide synthase in depolarized human temporal cortex slices: differential role of voltage-sensitive calcium channels.

1. Nitric oxide (NO) synthase activity was studied in slices of human temporal cortex samples obtained in neurosurgery by measuring the conversion of L-[3H]-arginine to L-[3H]-citrulline. 2. Elevation of extracellular K+ to 20, 35 or 60 mM concentration-dependently augmented L-[3H]-citrulline production. The response to 35 mM KCl was abolished by N(G)-nitro-L-arginine (100 microM) demonstrating NO synthase specific conversion of L-arginine to L-citrulline. Increasing extracellular MgCl2 concentration up to 10 mM also prevented the K+ (35 mM)-induced NO synthase activation, suggesting the absolute requirement of external calcium ions for enzyme activity. 3. However, the effect of high K+ (35 mM) on citrulline synthesis was insensitive to the antagonists of ionotropic and metabotropic glutamate receptors dizocilpine (MK-801), 6-nitro-7-sulphamoylbenzo(f)-quinoxaline-2-3-dione (NBQX) or L-2-amino-3-phosphonopropionic acid (L-AP3) as well as to the nicotinic receptor antagonist, mecamylamine. 4. The 35 mM K+ response was insensitive to omega-conotoxin GVIA (1 microM) and nifedipine (100 microM), but could be prevented in part by omega-agatoxin IVA (0.1 and 1 microM). The inhibition caused by 0.1 microM omega-agatoxin IVA (approximately 30%) was enhanced by adding omega-conotoxin GVIA (1 microM) or nifedipine (100 microM). Further inhibition (up to above 70%) could be observed when the three Ca2+ channel blockers were added together. Similarly, synthetic FTX 3.3 arginine polyamine (sFTX) prevented (50% at 100 microM) the K+-evoked NO synthase activation. This effect of sFTX was further enhanced (up to 70%) by adding 1 microM omega-conotoxin GVIA plus 100 microM nifedipine. No further inhibition could be observed upon addition of MK-801 or/and NBQX. 5. It was concluded that elevation of extracellular [K+] causes NO synthase activation by external Ca2+ entering cells mainly through channels of the P/Q-type. Other Ca2+ channels (L- and N-type) appear to contribute when P/Q-channels are blocked.

Alanine↗
PubMed1996

Double-blind stereo-EEG and FDG PET study in severe partial epilepsies: are the electric and metabolic findings related?

The aim of this study was to evaluate, in 16 patients with drug-resistant partial epilepsy who were waiting to undergo surgical treatment, the relation between positron emission tomography (PET) findings with fluorine-18 fluorodeoxyglucose ([18F]FDG) in the interictal state and the different stereo-electroencephalography (SEEG) patterns that characterize: (a) the epileptogenic zone (low-voltage fast-activity discharge before or concurrent with ictal clinical symptoms), (b) the irritative zone (spikes, spikes and waves, isolated or grouped in short bursts) and (c) the lesional zone (continuous, sometimes polyrhythmic slow waves or continuous delta waves or very important voltage depression). SEEG was performed following an individually defined electrode implantation strategy. Whereas at least one area of hypometabolism was detected by visual interpretation of PET/[18F]FDG images in all the subjects in the study, there was poor agreement between PET/[18F]FDG quantitative measures of regional metabolism and SEEG findings. Normal metabolic rates were found in up to 62% of the areas with abnormal SEEG activity, independent of the type of electrical activity, i.e. epileptogenic, irritative, or lesional, while abnormal metabolic rates were found in up to 23% of the areas with normal SEEG activity. In conclusion, whereas the visual interpretation of interictal studies of glucose utilization in our series of drug-resistant epileptic patients consistently allowed the localization of an area of temporal hypometabolism, the quantitative and regional metabolic analysis demonstrated that such a finding is not specifically related to any of the three very different SEEG patterns (epileptogenic, irritative, lesional) or combinations thereof. These results complement those of previous interictal and ictal single-photon emission tomographic studies and of receptor studies in epileptics, suggesting functional and biochemical heterogeneity within the interictal hypoperfused/hypometabolic area in epileptic patients, and contribute to the debate on the use and interpretation of interictal PET/[18F]FDG studies in patients with medically refractory partial seizures.

Adult↗
PubMed1996

[Clinical characteristics critical for patients "recovered" after surgical treatment for temporal lobe epilepsy].

We analyse subjective and objective clinical manifestations, in 33 patients, among the 63 with "pure" temporal lobe epilepsy, for which we obtained at least a video-EEG or video-stereo-EEG ictal recording. We compared video-EEG recordings (103 seizures, mean 3.9; min 1, max. 23) and video-stereo-EEG recordings (77 seizures, mean 3.2; min 1, max. 13) with anamnestical data, in order to define the degree of reliability of patient and relatives reports. Overall agreement between anamnestic and video-recorded informations is excellent for subjective symptoms, and fairly good for objective signs. Subjective manifestations (reported in 90.1% of this group) are described in detail as well as the objective ones, these latter split divided into early and late manifestations.

Electroencephalography↗
PubMed1996

[EEG video recording].

We analyse EEG data from video-EEG recordings of 24 patients, selected among the 63 with "pure" temporal lobe epilepsy. As to interictal EEG features, 62.5% of patients show a less regular background activity on the affected side, in 70% of patients slow waves are either localised or lobar, while in 58% are spikes. Slow waves and spikes have the same well-defined localisation in 37.5% of the patients. Ictal recordings show an initial EEG pattern with high localising value (low-voltage fast activity, flattening or slow waves interruption) in 74/121 seizures (61%). Five out of these 24 patients were operated on without invasive recordings on the basis of ictal video-EEG data. In the 19 patients left, video-EEG ictal informations were used for the planning of the stereo-EEG exploration.

Electroencephalography↗
PubMed1996

[Temporal lobe epilepsy: stereotaxic methods].

We give a description of stereotaxic methodology as originally elaborated by the S.te Anne Hospital School in Paris, and successively modified and utilised in Niguarda Hospital in Milan. Performing a stereotactic arteriography and ventriculography should allow the appreciation of minimal modification of vascular anatomy, identification of sulci and gyri by utilising stereoscopic technique and the proportional grid, based on bicommissural line, evaluation of the morphological abnormalities and their precise reconstruction in the intracranial space. Anatomical information obtained by this kind of examinations are essential for intracerebral stereo-EEG investigation and for planning surgical procedure.

Brain Mapping↗
PubMed1996

[Relationship between anatomic lesions of the temporal lobe and temporal lobe epilepsy].

A structural lesion of the brain is a frequent finding in intractable partial epileptic patients. We analyse anatomo-electro-clinical characteristics of 58 patients in which MR showed a lesion inside the temporal lobe. They are 29 males and 29 females with a mean age at surgery of 23.5 +/- 10.7 years (2.6-45.9). The mean epilepsy duration is of 13.4 +/- 8 years (1.3-35.5), with a mean seizure frequency of 28.7 +/- 43.6 per month, with a great inter-individual variability (from 3 per month to 15 a day). The minimum follow-up is 3.5 years. A video-EEG monitoring was performed in 21 cases, while a stereo-EEG investigation was judged mandatory in 26. On the basis of anatomo-electro-clinical correlations and of the results of presurgical investigations, the epileptogenic area was proved to be temporal in 49 cases, temporal but controlateral to the lesion in 1, and at least bilobar in 8 patients.

Adolescent↗
PubMed1996

[Short account of modern history of surgery in temporal lobe epilepsy].

We make an overview of the most significant historical steps of the temporal lobe epilepsies surgical treatment, from the first description, at the end of 19th century, to recent times. We also describe the history of neuropsichological testing (mainly Wada test), extra- and intra-cranial EEG-recordings, synchronised electro-clinical monitoring, structural and functional neuroimaging. We mainly tried to point out that the selection of candidates to surgical treatment should be based, despite any technological development, on a synoptical anatomo-electroclinical reasoning.

Diagnostic Imaging↗
PubMed1996

[Surgical treatment of temporal lobe epilepsy: reality and prospectives].

This chapter provides a synthetic overview of the topics treated in this issue. Presurgical diagnostic procedures are schematically described and an analysis of surgical results is made in comparison with those obtained from other epilepsy surgery groups. Surgical complications linked both to invasive presurgical diagnostic procedures and therapeutic surgical acts are described. Finally, the creation of new epilepsy surgery centres is suggested on the basis of epidemiological data, which demonstrate the discrepancy among the patients operated on at present and those who could benefit from the surgical treatment.

Decision Making↗
PubMed1996

[Characteristics of the global population].

We analyse clinical characteristics, presurgical investigations, surgical procedures and outcome of 137 patients operated-on for a drug-resistant partial epilepsy, in Grenoble from January 1990 to December 1993. Moreover we present data of 63 patients suffering from a "pure" temporal lobe epilepsy selected using the following criteria: 1. surgery limited to temporal lobe structures 2. totally cured after surgery (Engel's class la).

Adolescent↗
PubMed1995

Role of the hypothalamic hamartoma in the genesis of gelastic fits (a video-stereo-EEG study).

Patients having a hypothalamic hamartoma frequently present epileptic attacks of laughter, and they later experience multiple additional seizure types, which invariably lead to a severe drug-resistant epilepsy. If this association is now well-known, relationships between the hypothalamic mass and the different types of seizures remain still mysterious. We report the case of a 16-year-old girl suffering from this peculiar epileptic picture, in whom a stereo-EEG study was performed, allowing us to record both the hamartoma, the neighboring hypothalamic structures, and other bilateral cortical areas. It showed that gelastic fits were strictly linked to ictal discharges which began and remained well localized in the hamartoma. Conversely, atonic seizures, which might result from a secondary epileptogenesis, admitted a widely extended bilateral frontal cortical origin, sparing the lesion, and slightly involving the posterior hypothalamus. Stereotactic radiosurgery of the hamartoma proved to be ineffective on both types of seizures, probably because of the too low dose of X-rays delivered (18 grays), as suggested by the absence of hypothalamic mass changes on MRI. Such data, never reported to our knowledge, seem able to contribute to a better understanding of this very peculiar epileptic syndrome, and perhaps to a better adapted therapeutic management.

Adolescent↗
PubMed1995

Inter-ictal brain SPET in frontal epilepsy: correlations with stereo-electroencephalography.

Single photon emission tomography (SPET) imaging holds promise for localization of the site of extratemporal seizures, but limited data currently exist; in particular, correlations with stereo-electroencephalography (S-EEG) have not been made. Ten patients aged 14-44 years (mean 25 years) with a proven frontal or central epilepsy by S-EEG and post-surgical follow-up were studied retrospectively: 7 patients had frontal cortectomy and one patient had a callosotomy for bifrontal epilepsy. All patients underwent clinical, inter-ictal and ictal video-EEG, computed tomography scan and/or magnetic resonance imaging, SPET and S-EEG examinations. SPET was performed inter-ictally, while on usual epileptic medications, using 99Tcm-HMPAO (n = 4) or 123I-IMP (n = 6) as the perfusion tracer. The SPET images were evaluated independently by two observers, blind to any data other than the diagnosis of frontral or central epilepsy. Localization of inter-ictal SPET hypoperfusion was compared with the epileptogenic (EZ), irritative (IZ) and lesional (LZ) zones, as defined by S-EEG. Six patients showed structural frontal abnormalities. One patient had normal SPET and one had a contralateral hypoperfusion. Therefore, concordance of sides was found in 8 of 10 patients (including one with bilateral SPET and S-EEG abnormalities). The hypoperfusion was equal to or larger than the EZ + IZ + LZ in 6 patients (5 had a frontal lesion). SPET hypoperfusion was smaller than the EZ in one patient, and different from the EZ, IZ and LZ in two patients. Although this was a retrospective study, it provides qualitative data regarding the significance of inter-ictal SPET abnormalities in frontal or central epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Stereo-EEG of interictal and ictal electrical activity of a histologically proved heterotopic gray matter associated with partial epilepsy.

Magnetic resonance imaging allows the identification of heterotopic gray matter (HGM) in medically intractable partial epilepsies. The relationships between HGM and the epileptogenic zone remain, however, unclear. In a case of a temporo-parietal epilepsy studied by stereo-EEG, interictal and ictal electrical activity of a temporal HGM were recorded, showing: (1) an intralesional electrical activity, (2) the possible presence of asynchronous spikes, and (3) an early but never initial, or isolated, involvement during ictal discharges. This suggests that the presurgical and surgical management of HGM must be guided, as for other lesions, by the coherence existing between ictal clinical and electrical features, and anatomical data.

Adult↗
PubMed1994

Stereo-electroencephalography methodology: advantages and limits.

Since January 1990, 70 patients with medically intractable partial epilepsy underwent a stereo-EEG investigation in our center. We first described technical requirements, and gave an overview of the variety of the explored cerebral regions and implantation patterns realized, pointing out the low rate of morbidity (1.4%). The three-dimensional epileptogenic zone thus defined led to a tailored individualized surgical excision in 60 patients, while 9 are waiting for surgery and the remaining 1 has been excluded (1.4%). Conceptual and technical aspects of the stereo-EEG methodology were discussed in order to underline its peculiarities in the field of "depth recordings", and more generally among the broader group of "invasive" procedures.

Adolescent↗
PubMed1993

[Stimulators of the central nervous system].

Progress in biomedical engineering has provided implantable and programmable stimulators which allowed application of neurophysiological knowledge to therapeutic attempts on human neurological diseases. Chronic electrodes can be implanted accurately and safely into the brain, against the spinal cord and around the nerves. Therapeutic applications, mainly on pain, dyskinesias and epilepsy are therefore available, which call for careful clinical evaluation, basic and technological research to improve indications and diminish the cost of these methods.

Central Nervous System↗