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Biomedical subjects

L Ravagnati

Publications and source records attributed to L Ravagnati.

17 recordsLinked to original sources
PubMed1982

Differences between the concentrations of antiepileptic drugs in normal and pathological human brain.

The concentrations of antiepileptic drugs in histologically normal and pathological brain tissues were investigated in 6 patients submitted to surgery. No significant difference for phenobarbital and phenytoin was found between normal and scar tissue, whereas there was a trend to concentration in tumour tissue (meningioma and glioma) of phenobarbital, phenytoin and carbamazepine. Alteration in the vascular supply and pathological changes at cellular and subcellular levels could be responsible for the differences in the distribution of the drugs. The possible clinical relevance of the preferential concentration of the drugs in tumour tissue is discussed.

Adolescent↗
PubMed1980

Stereo-EEG and surgery in partial epilepsy with temporo-parieto-occipital foci.

Six cases of partial epilepsy operated on for lesions at the temporo-parieto-occipital junction are presented. Three cases had signs of enlargement of one lateral ventricle at the temporo-parieto-occipital carrefour, three had a lateral homonymous hemianopsia and all showed lateralizing interictal EEG abnormalities. The manifold features of the seizures could not be related to the involvement of one or more definite cortical areas. Since clinical, radiological, scalp EEG investigations provided no sufficient data to map the epileptogenic lesion to be excised, stereo-EEG studies with chronic depth electrodes were performed. Besides permitting the exact delimitation of the epileptogenic lesion, depth EEG gave the clue for interpreting physiopathological mechanisms underlying the electroclinical seizures in each case.

Adolescent↗
PubMed1980

Late results of stereotactic radiofrequency lesions in epilepsy.

Thirty-five patients with partial complex seizures and two patients with generalized epilepsy were treated by stereotactic radiofrequency lesions. Follow-up from 2 to 13 years was available in 30 patients. The stereotactic targets in patients with partial complex seizures were: a) Amygdala; b) Ammon's horns; c) parahippocampal gyrus; d) Fornix. Depending on scalp EEG and depth electrode studies, each patient had one or more target coagulated, unilaterally or bilaterally. In the 2 cases of generalized epilepsy, bilateral Forel field lesions were performed. Late surgical results are discussed in relation to the depth EEG studies and the number and site of stereotactic lesions.

Adolescent↗
PubMed1980

Antiepileptic drug distribution in cerebral cortex, ammon's horn, and amygdala in man.

Significant correlations in the concentrations of phenobarbital, phenytoin, and carbamazepine in the brain, plasma, and cerebrospinal fluid were found in 12 surgically treated epileptic patients. These findings confirm the clinical reliability of monitoring anticonvulsant drug plasma levels as part of the routine management of epilepsy. Phenobarbital, phenytoin, and carbamazepine are uniformly distributed in the gray and white matter in different brain areas (except for a higher concentration of phenobarbital in the rhinencephalic structures in comparison with the corresponding temporal neocortex) and in normal and scar tissue. In these 12 patients, all of whom were medically resistant, molar cortex concentration of phenobarbital and phenytoin was at "therapeutic" levels or even higher. These data suggest that in therapy-resistant patients, despite cerebral drug concentrations of the same therapeutic level as, or higher than, those present in medically controlled patients, anticonvulsant drugs are pharmacologically ineffective.

Adolescent↗
PubMed1979

Activity of human hippocampal formation and amygdala neurons during sleep.

Fine wire microelectrodes were implanted for diagnostic purposes in 17 patients suffering from psychomotor epilepsy. Single- and multiunit activity during waking and natural nocturnal slow wave sleep and REM sleep was recorded in the hippocampus (n = 42), hippocampal gyrus (n = 53), and amygdala (n = 32). The firing rates of hippocampal gyrus units usually decreased during slow wave sleep and then increased to levels equal to or above waking during REM. In contrast, the firing rates of hippocampal neurons generally increased during slow wave sleep and fell to very low levels during REM. The amygdala presented a more mixed pattern. Since the projection from the hippocampal gyrus to hippocampus is excitatory, their opposite patterns during sleep suggest that the tonic firing patterns of HC neurons may be mainly the result of subcortical afferents.

Afferent Pathways↗
PubMed1979

Interictal acute psychoses in temporal lobe epilepsy during withdrawal of anticonvulsant therapy.

Acute interictal psychotic attacks during withdrawal of medication are described in two patients with temporal lobe epilepsy submitted to depth EEG study with a view to surgical treatment. The patients were on chronic treatment with clonazepam associated in one with phenobarbitone and in the other with phenobarbitone plus carbamazepine. Our observations suggest that the acute withdrawal of clonazepam, the plasma levels of which were monitored may play a part in producing psychotic attacks characterised by dysphoric manifestations, irritability, aggressiveness, anxiety, and hallucinations. These symptoms could be interpreted as a withdrawal syndrome.

Adult↗
PubMedDate not supplied

Anal protrusion as a complication of ventriculo-peritoneal shunt. Case report and review of the literature.

A case is reported in which the Raimondi peritoneal catheter of a ventriculoperitoneal shunt spontaneously protruded from the anus in an infant. This complication has been previously reported; both pathogenesis and treatment may still represent a problem. From the review of the pertinent literature pathogenesis is mostly related to bowel perforation due to local infective adhesions. Treatment does not imply major abdominal surgery, if after avulsion of the extruded catheter and exteriorization of the shunt no peritoneal signs are present.

Anal Canal↗
PubMedDate not supplied

[Interruption of antiepileptic therapy in seizure-free patients following surgery to remove the epileptogenic lesion].

This paper presents a series of 20 epileptic patients operated on at our Institute, with a clinical, EEG and drug plasma level follow-up, for periods from 48 to 60 months. Following surgery a group of 12 patients were seizure-free in a 3 year period of follow-up, and anticonvulsant medication was gradually withdrawn. While in 8 of these patients drug interruption uneventful, in 4 cases drug withdrawal caused the seizure to reappear. These 4 patients became seizure-free again, following a reintroduction of pharmacological therapy, which appeared to be effective also at low doses. Another group of 8 patients continued to have seizure also after surgery. Following quantitative and qualitative adjustments of their anticonvulsant medication, 5 patients became again seizure-free, while 3 continued to have seizures. Our experience suggests that in patients in whom the epileptogenic lesions have been surgically removed, anticonvulsant therapy can be safely withdrawn and removed after a seizure-free period of 3 years. Reappearance of seizures after drug withdrawal has a good prognosis, since a simple readjustment of medical therapy is usually effective in preventing further seizures to occur.

Adolescent↗
PubMedDate not supplied

Cerebral protection with diphenylhydantoin during disobliterating surgery of the sovra-aortic branches.

Cerebral metabolic protection in patients submitted to carotid tromboendoarterectomy (TEA) can be made by means of drugs, both in the clamping acute intraoperative phase and in the immediate post-operative period. The knowledge that DPH has the property of reducing CMRO2, the lactates production and of increasing the cerebral level of glucose, glycogen and phosphocreatinine, has persuaded us to use this drug instead of barbiturate, as a therapeutic protection to prevent hypoxic damages to the nervous cell. Our series include 12 patients submitted to carotid TEA in whom cerebral metabolic protection has been obtained by means of DPH at the dosage of 15-17 mg/kg body wt. injected intravenously in about 15' just before clamping. Using this type of pharmacologic protection, we have not observed any of the undesired effects in the cardiocirculatory system described in the literature. The prompt awakening, the absence of neurological deficits, the absence of side-effects suggest that DPH can be used to provide a cerebral metabolic protection during TEA.

Cerebrovascular Disorders↗
PubMedDate not supplied

CT-scan and EEG findings in professional pugilists: early detection of cerebral atrophy in young boxers.

In order to evaluate the possibility of early detection of minimal cerebral damages in the professional boxers, ten young pugilists were submitted to complete neurological examination, EEG recording and CT-scan. Neuroradiological data, electrical patterns and neurological aspects were examined in connection with sporting career of each boxer. Neurological examination was normal in all cases. EEG patterns were considered normal in 3 cases, borderline in 4 cases and pathological in 3 cases. CT-scan was considered normal in 4 cases, borderline in 4 and pathological (showing signs of cerebral atrophy) in 2 cases. A good correlation was found between CT-scan pictures, EEG patterns and sporting career of the boxers: the pugilistis who suffered knockouts had pathological and/or borderline CT-scan and EEGs, while the pugilists who did not experience knockouts during their career showed a normal CT-scan and EEG, independently of the years of activity and number of matches.

Adolescent↗