Excitability cycle of the visual cortex during sleep and wakefulness.
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Biomedical subjects
Publications and source records attributed to G F Rossi.
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We observed 4 children with hemimegalencephaly, (3 boys, 1 girl aged 3-7 years). One child had a linear sebaceous nevus. All patients had a similar clinical, EEG, and neuroradiologic pattern. All patients had macrocrania, hemiparesis, hemianopsia, and psychomotor retardation of variable degree. All cases had an epileptic syndrome with onset during the first days or the first months of life. The seizures were consistently similar: partial motor seizures, generally hemiclonic and asymmetric brief tonic seizures, in series, involving predominantly one side of the body, contralateral to the cerebral damage. The EEG was initially characterized by a hemihypsarrhythmia and afterward, over the malformed hemisphere, by a rather high-frequency background activity associated with almost continuous transients of spikes, sharp waves, and spike and waves that progressively involved the contralateral hemisphere. Hemispherectomy was performed in two children with sudden and complete recovery from seizures and improvement in psychomotor development. Macroscopic examination was consistent with the computed tomography (CT) scan and magnetic resonance imaging (MRI) showing pachygyria and poorly represented white matter. Histologic examination showed the characteristic absence of cortical neuronal layering, and the presence of giant neurons, neuronal heterotopias, and gliosis. For hemispherectomy to be successful, we believe prolonged EEG monitoring is needed to verify that no seizures are originating in the normal hemisphere.
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The purpose of this paper is to propose a preliminary scheme which standardizes the terminology and the manner of classifying comatose states due to organic cerebral lesions. This attempt is based on recognition of the need to use a common language in order to facilitate the transmission of information in this field.
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Stereotactic biopsy is nowadays considered a diagnostic procedure indispensable for anyone dealing with neuro-oncology, though its role is still debated especially in comparison with the one of the direct surgical approach. The Authors examine the indications of stereotactic biopsy in the management of intracranial expanding lesions, reviewing their personal series of 793 cases surgically treated in the last 7 years; of these, 210 underwent stereobiopsy. The possibilities of the procedure, its reliability as well as the possible complications are analysed in detail. Finally, the crucial role played by the pathological examination in the diagnosis of neoplasia is particularly stressed.
Brachicurietherapy represents a low dose-rate irradiation able to deliver high focal doses within relatively small tumor volumes. Its application to brain tumors utilizing the stereotactic techniques is nowadays considered with growing interest. The Authors analyze, on the basis of their personal experience, the possibilities and the limits offered by this therapeutic procedure in neuro-oncology. The choice of the sources and their modality of application, the definition of the optimal dose/time and dose/volume ratio are the main problems taken into consideration and discussed.
In our study we evaluated the presence of steroid hormone receptors in a large series of endocranial tumors and investigated the possible correlations between receptor presence and levels and patient's age and sex. Our data indicate that steroid receptor behavior in the neoplasias considered is quite different from that observed in endocrine-related tumors, such as breast and endometrial cancer. Moreover, in neuroepithelial tumors an interesting difference between male and female subjects has been found regarding the receptor distribution in poor differentiated neoplasias.
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The results of a study on the effects of L-Dopa in brain-injured patients showing impairment of consciousness are reported. Fifteen patients were selected for this study. The degree of consciousness impairment, or level of coma, varied in the different patients. In all of them, however, the comatose state persisted unchanged for at least 6 days before the beginning of L-Dopa treatment. A gradual and progressive improvement of the level of consciousness, as well as of the EEG patterns, followed the administration of L-Dopa in patients whose treatment commenced while they were in comas III, II and I (classification of Fishgold and Mathis, 1959, and Rossi, 1962). On the other hand, the results of the treatment were questionable in the sequelae of coma (apallic syndrome, coma vigil, akinetic mutism). A direct relation between L-Dopa and consciousness improvement appears to be supported by: 1) the fact that the level of coma was stabilized for several days prior to L-Dopa treatment (see above); 2) the fact that consciousness improvement occurred abreast of L-Dopa dosage; 3) the observation in some patients that worsening followed the temporary withdrawal of L-Dopa treatment and, vice-versa, improvement followed its resumption. The hypothesis of neurochemical components in the processes responsible for the decrease of vigilance following cerebral injury would appear supported by the findings reported.
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