PubMed Health⌕ Search

Biomedical subjects

E Frecska

Publications and source records attributed to E Frecska.

At least 19 recordsLinked to original sources
PubMed2004

Effects of ayahuasca on binocular rivalry with dichoptic stimulus alternation.

RATIONALE: During binocular rivalry, two incompatible images are presented to each eye and these monocular stimuli compete for perceptual dominance, with one pattern temporarily suppressed from awareness. One variant of stimulus presentation in binocular rivalry experiments is dichoptic stimulus alternation (DSA), when stimuli are applied to the eyes in rapid reversals. There is preliminary report that in contrast with healthy controls, schizophrenic patients can maintain binocular rivalry even at very high DSA rates. OBJECTIVE: The study was undertaken to investigate whether binocular rivalry survives high rates of DSA induced by the South American hallucinogenic beverage ayahuasca. METHODS: Ten individuals who were participating in ayahuasca ceremonials were requested to volunteer for binocular rivalry tests (DSA=0, 3.75, 7.5, 15 and 30 Hz) without and after drinking the brew. RESULTS: Ingestion of ayahuasca increased mean dominance periods both in standard binocular rivalry conditions (no DSA) and tests with DSA. At higher DSA rates (15 and 30 Hz) the total length of dominance periods was longer on the brew. CONCLUSION: It is discussed that ayahuasca-induced survival of binocular rivalry at high DSA rates may be related to slow visual processing and increased mean dominance periods may result from hallucinogen-induced alteration of gamma oscillations in the visual pathways.

Adult↗
PubMed1998

Ventricular enlargement in poor-outcome schizophrenia.

BACKGROUND: A subset of patients with schizophrenia, defined on the basis of longitudinal deficits in self-care, may show a classic ("Kraepelinian") degenerative course. An independent validator of the phenomenologically defined Kraepelinian subtype might be provided by a structural indicator of possible brain degeneration: ventricular size as measured by computed tomography (CT). METHODS: To examine whether Kraepelinian patients would show a differential increase in ventricular size over time, two CT scans were conducted at intervals separated by > 4 years, an average of 5 years. Fifty-three male patients with DSM-III-R diagnoses of chronic schizophrenia were subdivided into Kraepelinian (n = 22; mean age = 42 +/- 6 years) and non-Kraepelinian (n = 31; mean age = 38 +/- 12.2 years) subgroups. Kraepelinian patients were defined on the basis of longitudinal criteria: > 5 years of complete dependence on others for life necessities and care, lack of employment, and sustained symptomatology. Thirteen normal elderly volunteers (mean age = 60 +/- 17.8) were also scanned at 4-year intervals. CT measurements were made by raters without knowledge of subgroup membership. A semiautomated computer program was used to trace the anterior horn, lateral ventricles, and temporal horns for each slice level on which they were clearly seen. RESULTS: The ventricles showed a bilateral increase in size over the 4-year interval in the Kraepelinian subgroup, more marked in the left hemisphere than the right. By contrast, neither the non-Kraepelinian subgroup nor the normal volunteers showed significant CT changes from scan 1 to scan 2. CONCLUSIONS: Thus, the longitudinal dysfunctions in self-care that characterize the Kraepelinian patients were associated with an independent indicator of brain abnormality.

Adult↗
PubMed1997

The Dose Reduction in Schizophrenia (DORIS) Study: a final report.

Twenty-one medication-free chronic schizophrenics were randomly assigned to three treatment groups: 50% blockade of the bromocriptine growth hormone (GH) response, 100% blockade or 10 ng/ml haloperidol. Only seven of the 21 patients showed a significant improvement after 6 weeks in positive psychotic symptoms; six of the seven responders came from the 50 and 100% blockade groups, suggesting greater efficacy at lower doses. Fifty percent blockade was associated with an average daily haloperidol dose of 3.2 mg and plasma haloperidol levels below the limit of detection (< 1 ng/ml). 100% blockade was associated with a daily dose of 6.5 mg and a plasma haloperidol level of 1 ng/ml. Negative symptoms significantly improved in only four of the 21 patients, and three of these patients were from the 100% blockade group. Twenty-nine patients currently receiving 20 mg/day haloperidol were randomly assigned to three treatment groups: placebo, 100% blockade of the GH response and 10 ng/ml. Patients in the placebo group showed significant deterioration along both the positive and negative symptom dimensions. There were no significant symptom differences between the 100% blockade and the 10 ng/ml groups. The patients in the 100% blockade group had on average a daily dose reduction from 20 to 11 mg/day and a 65% reduction in the plasma haloperidol level. There was a 70% difference in the average daily dose for 100% blockade between the two study arms. The higher daily dose in the dose-reduction arm may reflect receptor up-regulation and/or other "tolerance'-like mechanisms associated with chronic neuroleptic administration.

Adult↗
PubMed1997

Regional brain metabolic response to lorazepam in alcoholics during early and late alcohol detoxification.

Changes in GABA function have been postulated to be involved in alcohol tolerance, withdrawal and addiction. In this study we measured regional brain metabolic responses to lorazepam, to indirectly assess GABA function (benzodiazepines facilitate GABAergic neurotransmission), in alcoholics during early and late withdrawal. Brain metabolism was measured using PET and 2-deoxy-2[18F]fluoro-D-glucose after placebo (baseline) and after lorazepam (30 micrograms/kg intravenously) in 10 alcoholics and 16 controls. In the alcoholics evaluations were performed 2 to 3 weeks after detoxification and were repeated 6 to 8 weeks later. Controls were also evaluated twice at a 6 to 8 weeks interval. While during the initial evaluation metabolism was significantly lower for most brain regions in the alcoholics than in controls in the repeated evaluation the only significant differences were in cingulate and orbitofrontal cortex. Lorazepam-induced decrements in metabolism did not change with protracted alcohol withdrawal and the magnitude of these changes were similar in controls and alcoholics except for a trend towards a blunted response to lorazepam in orbitofrontal cortex in alcoholics during the second evaluation. Abnormalities in orbitofrontal cortex and cingulate gyrus in alcoholics are unlikely to be due to withdrawal since they persist 8 to 11 weeks after detoxification. The fact that there was only a trend of significance for an abnormal response to lorazepam in orbitofrontal cortex indicates that mechanisms other than GABA are involved in the brain metabolic abnormalities observed in alcoholic subjects.

Adult↗
PubMed1995

Severity of symptoms in chronically institutionalized geriatric schizophrenic patients.

OBJECTIVE: The goal of this study was to characterize the symptoms of geriatric, chronically ill, institutionalized schizophrenic patients and investigate age-related differences in schizophrenic symptoms and cognitive performance from early adulthood to late senescence. METHOD: The Positive and Negative Syndrome Scale and the Mini-Mental State examination were used to assess the schizophrenic symptoms and cognitive performance, respectively, of 393 institutionalized schizophrenic patients stratified into seven groups designated by 10-year age intervals from 25 years to over 85 years. RESULTS: In the comparisons of the seven age groups, significant differences between groups in positive and negative subscale scores on the Positive and Negative Syndrome Scale and in Mini-Mental State scores were revealed. Significant correlations between Mini-Mental State scores and Positive and Negative Syndrome Scale negative symptom scores, but not positive symptom scores, were found for all age groups, except for the youngest patients studied. Current treatment with neuroleptics and prior treatment with ECT, insulin coma, or leukotomy could not account for the poor cognitive performance of the older schizophrenic patients. CONCLUSIONS: The older schizophrenic patients continued to experience psychotic and nonpsychotic symptoms in senescence. Their positive symptoms were moderately less severe and their negative symptoms and cognitive impairment were significantly more severe than those of the younger patients. Somatic treatment appeared not to be responsible for the severe cognitive impairment and negative symptoms of the older patients. These data are relevant to chronically hospitalized geriatric schizophrenic patients but not necessarily to all geriatric schizophrenic patients.

Adult↗
PubMed1991

Serotonergic interhemispheric asymmetry: neurochemical and pharmaco-EEG evidence.

1. Postmortem neurochemical investigations revealed interhemispheric asymmetry in the mediofrontal region of human brain. Significantly higher right hemisphere serotonin metabolite (5HIAA) content as well as increased maximal imipramine binding (IB) were found in the right hemisphere than in the left side. 2. IB did not show a gender difference in the mediofrontal area. However, women had higher IB in the right orbital frontal cortex than did men. 3. In vivo pharmaco-EEG results tend to support the postmortem neurochemical data. Intravenous chlorimipramine resulted in an asymmetric topographic distribution of the P300 auditory evoked potential, peak amplitudes were shifted to the right hemisphere.

Adult↗
PubMed1991

Effects of adjunctive verapamil administration in chronic schizophrenic patients.

1. The efficacy of adjunctive verapamil on psychopathological symptoms and tardive dyskinesia was investigated in 22 chronic schizophrenic patients, who had partially responded to neuroleptics. 2. After 28 days verapamil administration (240 mg/day) a significant improvement was found in anxiety-depression, and in some positive and negative symptoms. Three of the 22 patients showed clinically pronounced global improvement. 3. The treatment was ineffective in tardive dyskinesia.

Adult↗
PubMed1991

Serotonergic interhemispheric asymmetry: gender difference in the orbital cortex.

The asymmetry of tritiated imipramine (IMI) binding sites (which are associated with serotonergic mechanisms) were investigated in the orbital frontal cortex in 6 women and men who died of natural causes, and who did not have a history of mental disorders. There was significant interhemispheric asymmetry in both sexes, higher Bmax on the right side compared with the left. The Bmax values of IMI binding in the right orbital cortex in women were significantly higher than in men. Our preliminary findings--gender difference of serotonergic mechanisms in some area of the human brain--are in accordance with the observed gender differences in a variety of serotonin-regulated behaviors (sexual behavior, aggression and impulse control), and serotonergic mental disorders (eating disorders, suicidal behavior, anxiety disorders and depression).

Aged↗
PubMed1990

Predicting neuroleptic response from a combination of multilevel variables in acute schizophrenic patients.

A predetermined set of 22 sociodemographic, psychosocial, clinical, neurocognitive and biochemical potential predictor variables was tested in 98 schizophrenic patients admitted for relapse. The patients were treated with neuroleptics, mostly with haloperidol, for 28 d. Ten of the 22 variables correlated significantly with the neuroleptic response. Using stepwise multiple regression analyses, an optimal combination of 5 predictors was found to be in hierarchical order: disturbances of premorbid adjustment, intensity of positive symptoms at admission, family history of schizophrenia, working ability during the year before admission and serum dopamine-beta-hydroxylase. The 5 best predictors explained 29% of outcome variance, and all 22 variables together explained 35%. Such neurological characteristics as neurological soft signs, handedness, abnormal voluntary movements, spontaneous blink rate and cognitive impairment did not predict the treatment response. Several psychopathological, psychosocial and clinical predictors known from the literature could also be confirmed by cross-validation.

Activities of Daily Living↗
PubMed1989

Prolactin response to fentanyl in depression.

Ten unmedicated female inpatients with major depression (DSM-III) and 10 healthy volunteer women were given an intravenous injection of 0.1 mg fentanyl at 9:00 AM and 9:00 PM on different days. The prolactin secretory response to this opioid agonist was investigated for 1 h with serial blood sampling. Repeated measures Analysis of Variance yielded a significant effect of fentanyl administration on prolactin secretion (p less than 0.0001), and there were elevated hormone responses in the evening (p less than 0.005). No group difference was seen between healthy volunteers and depressed patients, but four of the depressives showed the most blunted response, and three of these low responders committed suicide within 1 year.

Adult↗
PubMed1989

A pilot study of the role of prophylactic antiparkinson treatment during neuroleptic therapy.

The authors administered haloperidol 4.5 mg t.i.d. to 33 drug-free schizophrenic patients. Ten patients did not receive anything else (group HPL), while ten patients received procyclidine 5 mg t.i.d., and 13 patients were given promethazine 25 mg t.i.d. (groups HPRC and HPRM respectively) in addition. Seven patients dropped out of the HPL group and three out of the HPRM group, but none out of the HPRC group. These drop outs were due to the development of early extrapyramidal side effects, which were absent in the HPRC group. The findings suggest that antiparkinson prophylaxis is useful during commencement of therapy with high-potency neuroleptic agents.

Adult↗
PubMed1989

Multivariate analysis of monoamine indices in patients with chronic schizophrenia.

Levels of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), noradrenaline (NA), 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid and serum levels of prolactin (PRL) and dopamine-beta-hydroxylase (DBH) were measured in 42 chronic schizophrenic inpatients grouped according to their scores on the Brief Psychiatric Rating Scale (BPRS) and the Abnormal Involuntary Movement Scale (AIMS). Factor analysis was carried out on various combinations of variables. In patients with tardive dyskinesia (TD), cerebrospinal fluid DA, DOPAC, HVA, NA, and serum DBH were distributed into three factors; in patients without TD, these substances were assembled in only one factor. Cerebrospinal fluid DA, DOPAC, and HVA were dispersed in two factors in patients with severe positive symptoms versus one factor in subjects with mild productive signs. Factor structures diverged only when the variables listed above were included in the analysis. These findings support the hypothesis that both the dopaminergic and the noradrenergic system contribute to TD and that positive schizophrenic symptoms are associated with dopaminergic dysregulation.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Effect of adjuvant reserpine treatment on catecholamine metabolism in schizophrenic patients under long-term neuroleptic treatment.

The clinical and biochemical effects of adjuvant reserpine treatment were investigated in 12 chronic schizophrenic patients on long-term neuroleptic medication. The global severity of the symptoms using the Brief Psychiatric Rating Scale did not change significantly in the whole group, however, a moderate decrease in positive symptoms (factors though disturbance, activation and hostile-suspiciousness) was observed for 5 patients. Cerebrospinal fluid (CSF) noradrenaline levels showed a consistent decrease, but other biochemical parameters (CSF dopamine metabolites, platelet MAO and serum dopamine-beta-hydroxylase activities) did not change significantly. The changes of clinical symptoms and biochemical parameters did not show any correlation.

Adjuvants, Pharmaceutic↗
PubMed1988

Dexamethasone suppression test and coping behavior in psychosocial stress.

The dexamethasone suppression test (DST) and the Minnesota Multiphasic Personality Inventory (MMPI) were administered to 144 healthy inductees on day 2 of military service. One hundred and four of them completed a 120-item questionnaire describing their coping responses to this particular challenge. Thirty-six subjects (25%) failed to suppress plasma cortisol adequately. Their mean scores on the MMPI clinical standard scales were within the normal range. High postdexamethasone cortisol levels were associated with denial and passivity, and with low demand for social support. These results suggest that the DST might be more related to coping with a stressor than to a specific diagnosis. The authors speculate that high hypothalamic-pituitary-adrenal activity may have a primary role in psychological defense promoting inattention to the aversive aspects of stressful situations.

Adolescent↗
PubMed1988

Diurnal variation in fentanyl-induced hormone responses and side effects.

The prolactin (PRL) and thyrotropin (TSH) secretory response to the opioid agonist fentanyl (0.1 mg IV) was investigated with serial blood sampling in ten healthy women at 9 AM and 9 PM on different days. In five subjects saline control trials were also performed. A repeated-measures analysis of variance yielded a highly significant effect of fentanyl administration both on PRL and TSH secretion. In every case there were elevated hormone responses in the evening, and more drug-related subjective symptoms were reported at this time than before noon. These findings indicate a diurnal variation of opioid responsiveness, with lower sensitivity in the morning.

Adult↗
PubMed1987

Dexamethasone suppression test and depressive symptoms in schizophrenics and endogenous depressed patients.

Dexamethasone Suppression Test (DST) was given to 30 depressed and 30 schizophrenic patients. 10 depressed patients (33%) and 6 schizophrenics (20%) showed abnormal DST; the difference was not statistically significant. The DST-positive and DST-negative patients did not differ significantly in the total scores on anxiety-depression factor of the BPRS, either in the group of depressed patients or in schizophrenics.

Adult↗