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Biomedical subjects

P Benna

Publications and source records attributed to P Benna.

At least 37 records · Page 2Linked to original sources
PubMed1982

Brainstem auditory evoked potentials in postconcussion syndrome.

Brainstem auditory evoked potentials (BAEPs) were recorded from 55 patients with postconcussion syndrome (PCS) to elicit evidence of an organic and subclinical brainstem disorder. Fifteen patients (27.3%) showed abnormal responses unilaterally or bilaterally, especially for one or more interpeak latencies prolonged beyond the upper 99% confidence limits. Other 9 patients had borderline responses. The BAEP alterations were not correlated either with dizziness at the time of recording, or with vestibular troubles in the routine caloric test. Though BAEP abnormalities may be present a long time after injury, we found an improvement of responses in the majority of 14 re-tested patients. These data show that BAEP can give an objective demonstration of a reversible brainstem disorder in patients with PCS.

Adolescent↗
PubMed1981

Acute neurologic complications of hemodialysis. Study of 14,000 hemodialyses in 103 patients with chronic renal failure.

We have examined and subjected to statistical analysis the transient acute neurological complications arising in the course of hemodialysis in 103 patients with chronic renal failure (13,969 hemodialysis sessions). Our data show that such complications are multiform. Some of the symptoms are aspecific: headache, nausea and/or vomiting, muscle cramps. We have found these symptoms in over 96% of patients, often combined with extraneurological symptoms and phenomena, such as cardiocirculatory shock or increased blood pressure. The other symptoms denote real cerebral impairment: convulsions, consciousness disturbances, psychomotor agitation. They are present in 36% of the patients, but only 10.5% of the patients show a combination of at least two symptoms. In these patients the so-called "Disequilibrium syndrome" is present: its percentage in our case-series is similar to that reported in literature.

Adolescent↗
PubMed1979

Brain stem auditory evoked potentials and blink reflexes in quiescent multiple sclerosis.

Brain stem auditory evoked potentials (BAEP) and blink reflexes (BR) were studied in 25 patients with multiple sclerosis (MS), the diagnosis being definite according to McAlpine's criteria, in the quiescent phase, without signs of brain stem involvement. BAEP abnormalities were found in 64% of the cases and BR abnormalities in 60%. A good correlation between the two tests was found in most patients. The abnormalities consisted of delayed latencies and/or high intraindividual variability in shape and latency of BAEP and BR components. It seems that demyelination of brain stem pathways results not only in conduction slowing but also in more serious dysfunction of the generators of the evoked components.

Adolescent↗
PubMed1976

Further observations on carbamazepine plasma levels in epileptic patients. Relationships with therapeutic and side effects.

Plasma levels of carbamazepine, phenytoin and phenobarbital were monitored weekly over a period of 9 weeks in 20 epileptic patients unresponsive to treatment. No attempts were made to modify phenytoin and/or phenobarbital plasma levels; emphasis was on achieving carbamazepine plasma levels of 4 to 10 mug per milliliter. A remarkable drop in seizure frequency was attained within 2 to 3 weeks of monitoring, with carbamazepine plasma and concentrations within the desired range. Children disposed of the drug faster than adults. No effects of phenytoin and phenobarbital on carbamazepine plasma levels could be observed, while phenobarbital on carbamazepine plasma levels fluctuated remarkably without any relationship to carbamazepine levels. Transient leukopenia was present in most of the patients, while a significant reversible drop in red blood cells was observed in eight patients. The data reported confirm that with a careful monitoring of drug plasma levels, carbamazepine may exert a definite passive effect on seizure frequency in epileptic patients poorly responsive to therapy.

Adult↗
PubMed1976

[The influence of noise on the human central nervous system (author's transl)].

We studied the effects of the road noise on the central nervous system in a group of 40 normal adult subjects. The neurophysiological research included the following parameters: acoustic and visual evoked cortical potentials, percentage of EEG desynchronization, contingent negative variation (CNV) and sleep-EEG. The results showed in every subject a reduction of the amplitude of the acoustic evoked potential recorded during the road noise as against to that one we recorded during normal silence. This fact, also in contrast to the stability of the visual evoked potential during the road noise and the normal silence, permitted to verify the existence of a neuronal occlusion phenomenon interesting the evocative acoustic stimulus when the noise is provided at the same time. The study of the EEG desynchronization during the road noise compared to that one during the normal silence did not give any statistically difference. The study of the CNV gave analogous results. Only if we complete the research with the study of the base-personality of every subject by the Rorschachtest, we found significant differences among the neurphysiological parameters as the EEG desynchronization and the CNV during the normal silence and the noise in relation to the different levels of anxiety and endotensivity of every subject.

Acoustic Stimulation↗
PubMedDate not supplied

Peripheral-type benzodiazepine receptors and diazepam binding inhibitor-like immunoreactivity distribution in human peripheral blood mononuclear cells.

Peripheral-type benzodiazepine receptors (pBZr) in human lymphocytes have been detected only in mixtures of peripheral blood mononuclear cells (PBMC). The present investigation was designed to describe precisely the location of pBZr in the various sets and subsets of PBMC, purified using monoclonal antibodies to specific PBMC surface markers. Site densities and affinities of pBZr were measured in the intact cells by conventional binding, using 3H-PK 11195 as a ligand. Moreover, we used a specific radioimmunoassay to identify in these cells the presence of the polypeptide diazepam binding inhibitor (DBI), a putative endogenous ligand for various benzodiazepine receptors including the peripheral type. Two major findings are derived from these studies: first, the coexistence of pBZr and DBI, or closely related immunoreactive material, in all major lymphocyte sets and subsets, as well as in monocytes. And second, the significant correlation (r = 0.87, p < 0.001) observed between the density of pBZr in a given cell type and its abundance of DBI like-immunoreactivity (DBI-LI). For both pBZr and DBI-LI content the cell distribution was monocytes > B cells and large granular lymphocytes > T cells (CD3+ set or CD4+ and CD8+ subsets) (ANOVA: pBZr: F = 114.11, p < 0.001; DBI-LI: F = 20.79, p < 0.001). The results are discussed in terms of the possibility that DBI and pBZr might share a relevant interaction in immunocompetent elements, thereby contributing to a new route of connection between the immune and the nervous systems.

B-Lymphocytes↗
PubMedDate not supplied

Pharmacological treatment of epilepsy today.

The pharmacological treatment of epilepsy has not gone through remarkable changes in recent years. Treatment is based on few first choice drugs, the mechanism of action of which we do not yet know exactly. These include: phenobarbital, primidone, phenytoin, carbamazepine, valproic acid, ethosuximide, clonazepam. Choice of drug is determined by the kind of seizures presented by the patient, while successful treatment is determined by the kind of epilepsy. The present trend is the use of first line drugs in monotherapy, fixing individually the dosage according to the plasma levels. The results obtained with the GABA-agonists (progabide, gamma-vinyl GABA) and with some of the calcium-antagonists (flunarizine) seem promising.

Anti-Anxiety Agents↗