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Biomedical subjects

G P Sechi

Publications and source records attributed to G P Sechi.

At least 19 recordsLinked to original sources

Neurological disorders associated with Mycoplasma pneumoniae infection.

Neurological syndromes caused by Mycoplasma pneumoniae (MP) infection are occasionally reported in adults, usually in the post-infectious period, and three computed tomography documented cases have recently appeared in this journal. Here we present the cases of three young women with recent respiratory tract infection caused by MP some weeks prior to neurological complication documented by magnetic resonance imaging. Two cases suffered from demyelinating disorders of the central nervous system (CNS). The other case had a middle cerebral artery thrombosis, a rare complication of MP infection. Another potential risk factor for stroke in the latter case was the use of oral contraceptives. Recent infection with MP is discussed as a risk factor for cerebrovascular disorders and CNS demyelinating diseases.

Adolescent↗

P300 and executive function alterations: possible links in a case of Morgagni-Stewart-Morel syndrome.

To evaluate possible cause-effect relationships between hyperostosis frontalis interna and cognitive dysfunction, we performed a neurophysiological (event-related potentials, ERPs) and neuropsychological study in a case of Morgagni-Stewart-Morel (MSM) syndrome associated with frontal lobe compression. Neuropsychological evaluation evidenced selective impairment of executive function. Visual and auditory oddball ERPs revealed delayed P300 latency and reduced auditory P300 amplitude with multi-peaked morphology. ERP abnormalities and cognitive dysfunction could be due to the frontal bone-cortex conflict documented by neuroradiological investigations.

Cognition Disorders↗

Which syringomyelia is truly associated with multiple sclerosis?

Necrosis of the spinal cord within multiple sclerosis (MS) lesions was suggested as a putative cause of syringomyelic cavity development in MS. A number of evidences suggest however that mechanisms other than necrosis are pathogenetically relevant for cavity formation, possibly depending on the atypical topographical distribution of the demyelinative lesion and on the increased cerebrospinal fluid pressure into the central canal below the compression. Not coincidentally, the hypothesis of post-necrotic and ex-vacuo mechanisms leading to cavitation derives from Japanese studies where MS is characterised by high tissue destructive capability and, besides its rarity, has many differences from the more common Western MS type and similarities with the acute disseminated encephalomyelitis (ADEM). Our opinion is that different MS types (Asian and Western) are accompanied by nonuniform mechanisms of syrinx formation and that the Asian MS type shares common, post-necrotic mechanisms with ADEM.

Cerebrospinal Fluid↗

Brain interstitial fluid collected through implanted tissue cages.

The physicochemical properties of the whole-brain interstitial fluid (IF) are unknown. A volume of whole-brain IF sufficient for analysis was obtained through a small, hollow, multiperforated polypropylene sphere implanted for 4-5 weeks into the dog brain parenchyma. The main physicochemical properties of the whole-brain IF were characterized, in comparison with the physicochemical properties of cerebrospinal fluid and blood/serum.

Amino Acids↗

Phenobarbital-induced buccolingual dyskinesia in oral apraxia.

A young woman with oral apraxia and a well-defined brain lesion on CT scan developed buccolingual dyskinesia lasting 40 days after low phenobarbital (PB) doses. Disruption of the corticostriatal glutamatergic pathway from areas 6 and 4 may have been important both in causing oral apraxia and in lowering the threshold for PB-induced buccolingual dyskinesia.

Adult↗

Eating seizures and distraction-arousal functions. A case study.

Reports of epileptic seizures evoked by eating are very scarce in the literature. A review of the reported cases suggests that various mechanisms may act as triggering factors in this form of reflex epilepsy. We studied a 17-year-old boy in whom the seizures precipitated by eating had been prevented by giving him some alerting stimuli during the meal. The attention-arousal coupling sustained by the meal seems to play a role in triggering the attacks.

Adolescent↗

Distribution of diphenylhydantoin in the brain during experimental status epilepticus of the cat.

The distribution of diphenylhydantoin (PHT) (40 mg/kg i.p.) in the brain was investigated in cats with convulsive generalized (group 1) and focal penicillin-induced status epilepticus (group 2), and in controls. A significant increase in the amount of PHT entering the brain during the convulsive status was found, with peak brain levels at 45 min (12 +/- 3.2 micrograms/g vs. 6.0 +/- 0.8 in normal cats, P less than 0.05). In the focal status brain concentrations of PHT reached levels intermediate between controls and group 1 cats. At 15 min, elevated blood levels of the drug were paralleled by increased concentrations in the brain, whereas at 30 and 45 min other factors, such as changes in cerebral blood flow, cerebral pH, vascular resistance, metabolic derangement and blood-brain barrier disruption were presumably responsible for the altered brain PHT uptake. The relevance of these data to clinical practice is discussed, in relation to the treatment of human status epilepticus and the potentially neurotoxic effects of the drug.

Animals↗

Cardiac side effects of phenytoin and carbamazepine. A dose-related phenomenon?

Three patients with dystrophia myotonica and echocardiographic signs of subclinical cardiopathy had cardiac side effects during oral treatment with phenytoin sodium or carbamazepine. These side effects were dose related: ventricular tachycardia appeared at a toxic serum phenytoin level in one patient and disappeared as the concentration fell within the therapeutic range, and atrioventricular block grade 1 developed in two patients at low serum carbamazepine levels, its severity increasing with the drug level. Given the risk of dangerous side effects, cardiac status needs to be carefully assessed before administration of phenytoin or carbamazepine in the treatment of dystrophia myotonica.

Adult↗

Fatal hyperpyrexia after withdrawal of levodopa.

We studied a patient affected with idiopathic Parkinson's disease and levodopa-induced dyskinesias. Fatal hyperpyrexia followed simultaneous levodopa withdrawal and a decrease in the dosage of diphenhydramine. The clinical features were those of the neuroleptic malignant syndrome. The rapid decrease in dopaminergic activity may have been important in causing the syndrome.

Basal Ganglia Diseases↗

Brain atrophy, peripheral neuropathy and folic acid deficiency.

A woman with peripheral neuropathy and cerebral atrophy, both secondary to a selective folic acid deficiency caused by severe gastrointestinal disturbances, was given folic acid replacement therapy, which improved her clinical, blood and neurophysiological status.

Atrophy↗

The penetration of phenobarbital in generalized and focal penicillin-induced epileptic brain of the cat.

The penetration of phenobarbital (PB) into cerebral tissue was determined in cats rendered epileptic by parenteral penicillin and in cats with focal penicillin-induced epilepsy. The results were compared with those from normal controls. In both kinds of experimental models of epilepsy, PB penetration was impaired, although a gradual and progressive accumulation of the drug in the brain tissue was observed in all three groups of cats (binding occurring from time 30 min on). Similar to the events with other substances, such as carbamazepine, the prolonged epileptic activity may have contributed to the impaired penetration of PB, because of severe metabolic alterations secondary to seizures. The present data confirm previous reports indicating that epileptic seizures alter the pharmacokinetics of drugs.

Absorption↗

Carbamazepine versus diphenylhydantoin in the treatment of myotonia.

A double-blind controlled trial was performed on 6 patients affected with Steinert's disease in order to evaluate the efficacy of two different dosages of diphenylhydantoin (PHT, 200 and 300 mg/day) and carbamazepine (CBZ, 600 and 800 mg/day) on the myotonic afterdischarge. Both dosages of PHT and CBZ induced a significant improvement of myotonia. For PHT a trend towards decreased efficacy is pointed out at toxic or at high dosages.

Adolescent↗