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G Athanassenas

Publications and source records attributed to G Athanassenas.

9 recordsLinked to original sources
PubMed1992

Human brainstem auditory-evoked potentials in deep experimental diving to pressures up to 62.5 bar.

The neural mechanisms underlying the high pressure neurologic syndrome (HPNS), which limit man's safe advance to extreme diving depths, are still unclear. This work was aimed at a better understanding of HPNS through study of brainstem auditory-evoked potentials (BAEP). BAEP were repeatedly recorded within 2 experimental chamber dives, Titan VIII (2 divers, maximum depth of 560 msw, compression time to bottom 109 h) and Titan XI (3 divers, maximum depth of 615 msw, compression time to bottom 240 h). Prolongation of the IV/V-complex occurred in 2 divers upon reaching 525 msw during Titan VIII compression and was accompanied by vestibular disturbances and amplitude increases of finger tremor. Both categories of changes--clinical signs and IV/V delay--gradually diminished during a 4-day stay at 545 msw, suggesting that they depended on excessive compression rates and insufficient acclimation time. Longer holding times at intermittent depths during Titan XI clearly reduced both HPNS symptoms and magnitude of prolongation of IV/V latencies. Wave I and wave III latency did not significantly change, pointing to a suppression of pontomesencephalic transmission. We infer that pressure suppresses synaptic transmission or triggers an increase of cortical or subcortical efferent inhibitory modulation of upper pontine and midbrain auditory afferents. Postdive controls revealed no persistent changes of BAEP measures in either the Titan VIII or XI divers.

Adult↗
PubMed1985

Prevalence of DSM III schizophrenia among the first-degree relatives of schizophrenic probands.

The extent of the genetic component, if any, in DSM III schizophrenia still remains unresolved. To further examine the issue, the first-degree relatives of 116 DSM III schizophrenic probands in our department were compared with those of an equal number of normal subjects, randomly selected and matched for age and sex. More than three fourths of the surviving relatives of each group were interviewed and rated according to DSM III criteria. Information of varying degrees of completeness was obtained about the remainder (surviving and dead). The gathered data were sufficiently detailed to provide general evidence that schizophrenia, and schizophrenia-related personality disorders were significantly more common in the first-degree relatives of DSM III schizophrenic probands than in the relatives of the controls. These findings suggest that even narrowly defined schizophrenia, such as that obtained by using DSM III criteria, has also a genetic component.

Adult↗
PubMed1983

Psychotic depressive disorder. A separate entity?

Two groups of patients suffering from primary unipolar major depressive disorder, one with (n = 145) and one without (n = 119) psychotic disorders were compared, in order to elucidate whether psychotic depressive disorder represents a distinct subtype or a severe variation of the illness. Except for more frequent appearance of psychomotor disturbances among the psychotic depressives, no demographic, family history and course variables were found to distinguish between those with or without psychotic features. The findings from our study are compatible with the view that psychotic depressive disorder is a severe variant of major depressive illness.

Affective Disorders, Psychotic↗
PubMed1983

Serum calcium and magnesium levels in chronic schizophrenics.

Serum calcium and magnesium levels were studied during neuroleptic treatment in a group of 29 chronic schizophrenic inpatients who had previously remained drug free for at least 4 weeks. The drug-free values of both electrolytes were not significantly different between patients and controls. In three patients who developed catatonic stupor during the drug-free period, calcium was significantly increased at the onset of the catatonic manifestations. Both electrolytes were significantly decreased in the whole group during treatment; the magnitude of the decrease was independent of the neuroleptic used. No correlation was found between the observed increase in prolactin and calcium changes. Patients who remained free of extra-pyramidal symptoms had a higher mean drug-free magnesium to calcium ratio compared to those who developed such symptoms. Our study provides evidence for an interconnection between serum electrolyte changes and neuroleptic drug action.

Calcium↗
PubMed1982

Differences in lateral brain ventricular size among various types of chronic schizophrenics. Evidence based on a CT study.

Data from a previous study of ours, based on computerised tomography of the brain in 70 chronic schizophrenics, indicated that a severe degree of lateral brain enlargement was present in a great proportion. No correlation was found between lateral ventricular enlargement and age of patients, length of illness, duration of hospitalization or ECT treatment. In order to elucidate whether other factors (e.g. type of disease) are likely to correlate with the enlargement we divided these patients into three subgroups: hebephrenics, paranoids and undifferentiated. Comparison of the mean values of ventricular brain ratio (VBR) of the above groups showed that paranoids presented a statistically greater enlargement than hebephrenics. There was no statistically significant difference between undifferentiated and hebephrenics. The difference between undifferentiated and paranoids approached statistical significance. This study provides evidence that there exists a difference between the types of schizophrenia in CT images, a finding that may suggest different degrees of underlying disease process.

Adult↗
PubMed1982

HLA antigens in schizophrenia: no difference between patients with and without evidence of brain atrophy.

The HLA antigens distribution was studied in 56 chronic schizophrenic in-patients with or without brain atrophy determined by CAT examination, and compared with that of 200 controls. There was no difference in the incidence of HLA-A2 in the whole sample, and an increase in those without brain atrophy (by comparison with normal controls) failed to reach statistical significance. A decrease of Bw35 in the whole sample, more prominent in those without brain atrophy, again failed to be significant after multiplying the probability by the number of antigens studied.

Adult↗
PubMed1980

Seasonality of the episodes of recurrent affective psychoses. Possible prophylactic interventions.

This study is an attempt to ascertain whether evidence for seasonal variations of the episodes of recurrent affective psychoses can be found in patients in Greece. Due allowance has been made for the fact that different socio-cultural and above all climatological factors prevail in Greece as opposed to other countries, which might be relevant in the phenomenon of seasonality. The seasonal distribution of the psychotic episodes, either depressive or manic, has been examined for 533 patients with various forms of affective psychoses, admitted to and treated in the State Mental Hospital of Athens, Greece, during the last 50 years. Statistically significant seasonal variation with peaks in spring was found for both depressive and manic episodes of various subgroups of patients, divided according to the I.C.D.-9.

Affective Disorders, Psychotic↗
PubMed1976

Air operations and circadian performance rhythms.

This paper reviews experimental results and pertinent data from the literature on circadian behavioural rhythms and their modifications through various factors. It relates them to the operation of aircrews "round the clock" and on transmeridian routes and discusses some possibilities of an appropriate scheduling.

Aerospace Medicine↗