Biomedical subjects
Publications and source records attributed to V Palma.
The functional integrity of the main sensorial systems and of the central motor pathways can be evaluated through multimodal evoked potentials and non-invasive transcranial stimulation of the motor cortex. In this review the authors summarize the main clinical indications of the afore said methods specifically in the field of the neurological disorders.
The intraoperative evoked potential monitoring has become indispensable in patients at risk for neurologic damages during surgery. This review presents the principal clinical indications for intraoperative monitoring of sensory and motor functions of spinal cord as well as of the auditory, facial and optic nerves and of brain functions during cerebrovascular surgery.
Focal, limbic seizures were produced by systemically administered pilocarpine (200 mg/kg, i.p.); as previously described this dose produces limbic stereotypies but neither convulsions nor seizure-related brain damage. The pretreatment, 5 minutes prior pilocarpine, with the D-1 agonist SKF 38393 (-ED50 = 1 mg/kg; i.p.) induced convulsions similar to those produced by a higher, convulsant dose of pilocarpine. On the other hand, the pretreatment with the D-2 agonist LY 171555 failed to induce convulsions. The D-1 receptor antagonist SCH 23390 prevented the convulsions induced by SKF 38393 plus pilocarpine (200 mg/kg). This study indicates that D-1, but not D-2, receptor stimulation converts subconvulsant doses of pilocarpine into convulsant ones.
Electroretinogram was performed in 18 patients with inherited ataxias. Eight had Friedreich's disease, 9 autosomal dominant cerebellar ataxia and one early onset cerebellar ataxia with retained tendon reflexes. Abnormalities were found in one patient for each group. The most frequent were decreased b-wave amplitude in photopic and scotopic conditions and prolonged implicit time.
We have performed otoneurological examination in a case of vermis cerebelli agenesia, CT scan confirmed. Visuo-vestibular interaction (VST) abnormality, with normal saccades and normal smooth pursuit movements, allows to suppose normal functioning of the flocculus and a damage in the nucleus olivaris inferior and, particular, in the paraolive.
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Deliberate inhalation of volatile substances is a common and harmful phenomenon among young persons around the world. Clinical and cytogenetic studies were performed in 35 children (33 boys and 2 girls) chronically habituated to inhalation of volatile agents, with the aim to define whether this practice is associated with chromosome abnormalities and if so to what extent. A significant increase in the rate of chromosome abnormalities and in the frequency of sister chromatid exchanges (SCE) was found in sniffers over the values in controls (p less than 0.001). Clinical, socioeconomic, and cytogenetic findings are discussed.
Glutamate dehydrogenase (GDH) activity was studied in 17 regions of six human brains. Duration and conditions of the postmortem period did not affect enzyme activity. Specific activity ranged between 103 and 377 nmoles/min/mg protein at 25 degrees C and it was 10-fold higher than that found in leukocytes. Apart from exclusively white matter regions (corpus callosum and centrum ovale), there was a moderate regional distribution (2.5-fold variation), with highest values in the inferior olive and hypothalamus, and lowest in the cerebellum and lenticular nucleus. With alpha-ketoglutarate (alpha-KG), NADH, or NH4+ as variable substrate, the apparent Km values in human brain were Km alpha-KG = 1.9 X 10(-3) M, KmNADH = 0.21 X 10(-3) M, and KmNH4+ = 28 X 10(-3) M, and in leukocytes they were Km alpha-KG = 1.7 X 10(-3) M, KmNADH = 0.24 X 10(-3) M, and KmNH4+ = 28 X 10(-3) M. The effects of cofactors, inhibitor, and pH were similar in brain and leukocyte GDH.
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