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Biomedical subjects

A Barocka

Publications and source records attributed to A Barocka.

At least 19 recordsLinked to original sources
PubMed1999

Dose-dependent stereoselective activation of the trigeminal sensory system by nicotine in man.

RATIONALE: Nicotine applied to the nasal cavity can evoke 'odorous' sensations in the concentration range near the detection threshold by the activation of the olfactory sensory system and at higher concentrations 'burning' and 'stinging' sensations by the dose-dependent recruitment of C- and Adelta-fibers of the trigeminal sensory system. Neuronal nicotinic acetylcholine receptor (nAchR) subunits are expressed in trigeminal primary afferents and could constitute the receptors involved in nicotine perception. OBJECTIVE: In the present study, we dose-dependently investigated the stereoselective effects of R(+)- and S(-)-nicotine on the trigeminal and olfactory sensory system in man. METHODS: Trigeminal detection thresholds for the 'burning' and 'stinging' sensations and the olfactory detection threshold for the 'odorous' sensation were determined. In order to quantify trigeminal activation, we recorded summated electrical responses from the respiratory nasal mucosa during stimulation with R(+)-and S(-)-nicotine vapor (40, 80, 120, 160 ng/ml; stimulus duration: 250 ms). In addition, subjects rated the intensity of 'odorous', 'burning' and 'stinging' sensations. For chemical stimulation with nicotine enantiomers, a vapor-dilution olfactometer (constant flow rate: 140 ml/s, humidity: 80%, temperature: 37 degrees C, stimulus duration 250 ms) was employed. RESULTS: We found significant stereoselective differences for the trigeminal but not for the olfactory system, i.e. higher summated responses, higher trigeminal intensity estimates, and lower trigeminal detection thresholds for S(-)- compared to R(+)-nicotine. CONCLUSION: Our results clearly demonstrate the different stereoselective activation of the trigeminal sensory system by R(+)-and S(-)-nicotine, indicating the presence of specific stereoselective receptors on trigeminal nociceptive Adelta- and C-fibers.

Adult↗
PubMed1999

Spontaneous slow and fast MEG activity in male schizophrenics treated with clozapine.

RATIONALE: The atypical neuroleptic clozapine induces specific electroencephalogram changes, which have not been investigated using the technique of magnetoencephalography (MEG). OBJECTIVE: The present study investigated whether spontaneous magnetoencephalographic (MEG) activity in patients treated with clozapine differs from that in patients treated with haloperidol and untreated control subjects. METHODS: A 2 x 37 channel biomagnetic system was used to record spontaneous magnetic activity for the frequency ranges (2-6 Hz), (7.5-12 Hz), (12.5-30 Hz) in schizophrenic patients and controls in two trials within 3 weeks. After data acquisition, the processed data were digitally filtered and the spatial distribution of dipoles was determined by a 3-D convolution with a Gaussian envelope. The dipole localisation was calculated by the dipole density plot and the principal component analysis. The target parameters were absolute dipole values and the dipole localisations. The relationship between absolute dipole values, dipole localisations and psychopathological findings (documented by the use of the PANSS, BPRS-scale) during a 3 week period with constant doses of clozapine and haloperidol was investigated using correlation analysis. RESULTS: Our results lend strong support to the assumption of a significant elevation of absolute dipole values [dipole density maximum (Dmax), dipole number (Dtotal), absolute and relative dipole density] in the fast frequency range (12.5-30 Hz) over the left hemisphere, especially in the temporoparietal region by clozapine. In this area, we found a dipole concentration effect only in patients treated with the atypical neuroleptic, whereas the dipole distribution in patients treated with haloperidol and healthy controls was concentrated in the central region. With regard to the absolute dipole values in the frequency ranges 2-6 Hz (delta, theta) and 7.5-12 Hz (alpha), we found no statistically significant differences between the groups investigated. In the slow frequency range (2-6 Hz) no difference was found between the clozapine and haloperidol group for the dipole localisation, which predominated in the temporoparietal region, in contrast to the central dipole distribution in control subjects. CONCLUSIONS: The results of an increase in beta activity under clozapine demonstrate a smaller reduction in activity in terms of unspecific sensory and motor paradigms in comparison with typical neuroleptics. The temporoparietal concentration of dipoles, in particular over the left half of the brain, might illustrate either their special role in the disease process, or the effects of the medication. The latter possibility was supported by the differing dipole distribution in the clozapine group with a left temporoparietal centre in both frequency ranges, and a deviating central dipole localisation in the fast activity range in the haloperidol group.

Adult↗
PubMed1998

Effects of tryptophan depletion in drug-free depressed patients who responded to total sleep deprivation.

BACKGROUND: There is some evidence that sleep deprivation (SD) might exert its antidepressant properties by involving serotonergic mechanisms. We investigated the effects of short-term tryptophan depletion (TD) on depressed patients who responded to a single night of total SD. METHODS: Drug-free depressed inpatients (n = 30) were randomly assigned to either TD or sham depletion. Tryptophan depletion was induced by a 24-hour low-tryptophan diet (day 1) followed the next morning by ingestion of a tryptophan-free amino acid mixture (day 2). During sham depletion, the diet and the amino acid beverage were supplemented with tryptophan. Sleep deprivation was performed from day 1 until day 2. Only SD responders received the amino acid beverage the morning after SD. Behavioral ratings and total and free plasma tryptophan levels were obtained before and after the test sessions. RESULTS: Twenty-two of 30 patients showed a favorable outcome after SD. As predicted, TD significantly lowered total and free plasma tryptophan levels, whereas both levels increased during sham depletion. No acute effects on mood were observed during the day after SD in either treatment group. Unexpectedly, TD, but not control testing, prevented the depressive relapse after the recovery night in most of the patients. CONCLUSIONS: Tryptophan depletion did not reverse the antidepressant effects of SD, but it prevented the relapse beyond a night of recovery sleep. These findings suggest that SD does not act via a single monoamine-related mechanism, but they allow the assumption that TD may induce neurochemical alterations that transiently improve depression.

Adult↗
PubMed1998

Neuropsychological results of craniopharyngioma surgery in adults: a prospective study.

BACKGROUND: The optimal management of craniopharyngiomas is a topic of ongoing debate. Supporters of limited surgery for craniopharyngiomas claim that more radical approaches are afflicted with adverse neuropsychological sequelae. Since prospective studies on this issue have not yet been performed, we assessed neuropsychological functioning in adults before and after craniopharyngioma surgery. METHODS: Thirteen adults with an age range of 17-76 years (mean, 45 years) were included in the study. Surgery included a transcranial procedure in 10 patients. The bifrontal interhemispheric approach predominated (n = 7). Neuropsychological evaluation was performed before and 3 months after surgery. The test battery was adjusted to evaluate function related to structures in the operative trajectory and at the tumor site. RESULTS: A complete tumor removal was accomplished in eight patients and subtotal removal in three patients. IQ scores for verbal intelligence were in the normal range and not affected by surgery (mean IQ score preoperative: 106.8; postoperative 107.4). In 12 of 13 patients, immediate recall, delayed recall and recognition memory were not impaired after surgery. Postoperative results for abstract thinking were in the normal or above-normal range. Cognitive speed was impaired in three patients preoperatively and in two patients postoperatively. Overall results were significantly better after surgery. Word fluency was not affected by surgery. Quality of life for the category "sleep" was impaired preoperatively, and this improved after surgery. Otherwise, quality of life was normal both before and after surgery. CONCLUSIONS: Neuropsychological performance and quality of life are generally not impaired after surgical removal of craniopharyngiomas. The findings support the attitude that the initial therapy of craniopharyngiomas should be an attempt at total removal.

Adolescent↗
PubMed1998

Effects of tryptophan depletion in fully remitted patients with seasonal affective disorder during summer.

BACKGROUND: Deficiencies in brain serotonin function are believed to play an important role in the pathophysiology of seasonal affective disorder/winter type (SAD). However, no direct evidence has been reported so far that lowered brain serotonin activity causes the symptoms of SAD. METHODS: We studied 11 SAD patients who had suffered recurrent winter depressive episodes of SAD and were fully recovered and off treatment during the summer. In a randomized, balanced, double-blind crossover design patients received two amino acid beverages, one containing tryptophan and the other containing no tryptophan but otherwise identical. Behavioural ratings and plasma total and free tryptophan concentrations were assessed at baseline before administration of the amino acid beverages and at several time points afterwards. RESULTS: The tryptophan-free amino acid beverage induced significant decreases of plasma total and free tryptophan levels and both levels increased during sham depletion (condition x time interaction: P < 0.001). Tryptophan depletion, but not sham depletion caused a transient return of depressive symptoms (condition x time interaction: P < 0.001). CONCLUSIONS: The present study demonstrates that SAD patients in remission during the summer are vulnerable to a return of depression when depleted of tryptophan. This finding supports the importance of serotonergic mechanisms in the pathophysiology of SAD.

Adult↗
PubMed1998

Weight of adrenal glands may be increased in persons who commit suicide.

In a previous study, increased weight of the adrenal glands was found in a small group of persons who committed violent suicides. This finding was confirmed in our study, which comprised a group of 42 suicide cases and 37 control cases. Further analysis with special consideration toward a "relative adrenal weight" (weight/body surface) revealed that a relative combined adrenal weight >6 g/m2 may be a morphologic sign of a depressive disorder prior to death if no other disease with a known effect on the adrenals is present. These results are consistent with clinical computed tomographic findings of enlarged adrenals in depressed patients. In all suicide cases the police records were reviewed and a postmortem psychiatric diagnosis conducted to investigate whether a correlation between adrenal weight and the "severity" of depression or type of psychiatric disorder exists. In thirteen cases, psychiatric treatment prior to death was known, and a postmortem severity score of depressive disease was formed. No influence of this score or the postmortem diagnosis on the adrenal weight, however, could be detected. Also, the increase in weight of adrenal glands could not be explained by a suspected or proven preceding drug therapy or use. The effect on the pituitary-adrenal-axis by depressive disorders and changes in serotonin metabolism have been investigated repeatedly; mainly reported are increased levels of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) in the depressive interval, which may lead to a growth of the adrenal glands.

Adrenal Glands↗
PubMed1997

Duration of lithium treatment and brain lithium concentration in patients with unipolar and schizoaffective disorder--a study with magnetic resonance spectroscopy.

Twenty psychiatric patients on lithium medication were examined with 7-Li-magnetic resonance spectroscopy of the brain. Patients on long-term lithium treatment (> 6 months) were compared with a short-term group who had been taking lithium for between 4 and 8 weeks. Patients met DSM-III-R criteria for either recurrent unipolar depressive disorder (DSM-III-R 296.3x) or schizoaffective disorder, depressive type (DSM-III-R 295.70). The brain:serum lithium ratio was 0.76 +/- 0.26; there was no significant difference between short-term and long-term treatment. In the group of long-term treatment patients there was a positive correlation between lithium dose per day and brain lithium concentration (R = .72, p < .01), and between lithium plasma concentration and brain lithium concentration (R = .65, p < .05). In the short-term group, however, there was no significant correlation for these parameters. No differences between unipolar and schizoaffective disorder were found.

Adult↗
PubMed1997

Influence of season on manifestation of schizophrenic subtypes.

In the modern classification systems ICD-10 and DSM-III-R, the term seasonality has been given a separate significance in the diagnostic categorization of affective disorders. Its definition is oriented not merely to the increased seasonal prevalence in the autumn and winter months, but also to symptoms that do not occur in nonseasonal attacks. To date, research work on seasonality in schizophrenia has concentrated on birth seasonality, while no results based on large populations of patients have yet become available on the manifestation seasonality of schizophrenic subtypes. Within the framework of a retrospective study carried out in the period between 1983 and 1995, involving 2, 119 patients suffering from recurrent attacks of schizophrenia, seasonal manifestations were recorded in accordance with the criteria defined in DSM-III-R. It was found that the two subtypes of paranoid hallucinatory and schizoaffective psychoses met the criterion of seasonality significantly more frequently than did the subtypes disorganized and catatonic disorders. In addition, seasonal courses within the groups just mentioned clearly differed from the nonseasonal forms in terms of their symptomatology.

Adult↗
PubMed1997

Rapid tryptophan depletion in drug-free depressed patients with seasonal affective disorder.

OBJECTIVE: Brain serotonin systems might be involved in the pathophysiology of seasonal affective disorder. The authors tested whether tryptophan depletion alters the mood of depressed patients with seasonal affective disorder. METHOD: Eleven drug-free depressed patients with seasonal affective disorder underwent tryptophan depletion in a placebo-controlled, double-blind crossover study. Tryptophan depletion was induced by a 24-hour low-tryptophan diet and by ingestion of a tryptophan-free amino acid beverage. During control testing the diet and the beverage were supplemented with tryptophan. Behavioral ratings and plasma total and free tryptophan levels were obtained before the diet started and several times after administration of the beverages. RESULTS: The diet and the tryptophan-free amino acid drink reduced plasma total and free tryptophan levels by 79.0% and 87.5%, respectively. Both levels increased during control testing. No significant behavioral changes were induced by tryptophan depletion or control testing. CONCLUSIONS: The failure of tryptophan depletion to exacerbate the depressive syndrome suggests that dysfunctional serotonergic activity does not play a primary, direct role in the pathogenesis of winter depression.

Acute Disease↗
PubMed1995

Residual symptoms after partial remission: an important outcome in depression.

This paper draws attention to an important adverse outcome in depression, the occurrence of residual symptoms after partial remission. Among patients with definite major depression followed every 3 months to remission and thereafter, residual symptoms reaching 8 or more on the Hamilton Depression Scale 17-item total were present in 32% (19) of the 60 who remitted below major depression by 15 months. The pattern was of mild but typical depressive symptoms. Residual symptoms were more common in subjects with more severe initial illness, but were not related to any other predictors, including longer prior illness, dysthymia, or lower dose of drug treatment during the illness episode. There were weak associations with personality that might have been consequences of symptom presence. Residual symptoms were very strong predictors of subsequent early relapse, which occurred in 76% (13/17) of those with residual symptoms and 25% (10/40) of those without.

Adolescent↗
PubMed1994

Single photon emission computerized tomography assessment of cerebral dopamine D2 receptor blockade in depression before and after sleep deprivation--preliminary results.

The antidepressant properties of total sleep deprivation (TSD) have been well established. There is some evidence that TSD may improve depression by altering central dopamine (DA) function. We therefore studied five depressed TSD responders and five TSD nonresponders after sleep and after TSD and five controls after sleep with IBZM single photon emission computerized tomography (SPECT). Responders showed a significant decrease (Wilcoxon--test p < 0.05) of relative basal ganglia D2 receptor occupancy after TSD compared to nonresponders (change score responders versus nonresponders p < 0.05, U-test). The data are interpreted as a sign of an enhanced DA release in responders. The results confirm previous hypotheses of dopaminergic involvement in the therapeutic action of TSD and indirectly support a dopamine hypotheses of depression.

Adult↗
PubMed1993

A test-retest study of cerebral blood flow during somatosensory stimulation in depressed patients with schizophrenia and major depression.

Six depressed patients with schizophrenia and 6 depressed patients with major depression were investigated before and during somatosensory stimulation (SS) with Tc-99m HMPAO SPECT. 8 controls were investigated only under resting conditions. The results can be summarized as follows: 1. Both psychiatric patient groups were hypofrontal (dorsolateral prefrontal cortex) compared to controls. 2. Hypofrontality was further enhanced by SS, significantly only in affective psychoses in the right inferior frontal lobe and in the right frontal hemisphere in total, in schizophrenia in the left dorsolateral prefrontal cortex. 3. Within the frontal lobes different regions were affected by SS in the two diagnostic groups. 4. In the right inferior parietal lobe SS response was significantly different in the two illnesses with schizophrenia showing a relative decrease, affective psychoses showing a relative increase of activity. 5. SS produced an increase of cerebral blood flow in subcortical regions (statistically significant contralateral to SS in thalamus and basal ganglia, ipsilateral to SS in cerebellum), a pattern which was common to all psychiatric patients. 6. Somatosensory cortex flow was not changed by SS. In conclusion, we could not fully confirm our hypotheses that similar blood flow abnormalities in different illnesses during SS are only caused by similarities in depressive psychopathology. Instead, depressed patients with schizophrenia were different from depressed patients with major depression in showing decreased activity in interrelating brain regions participating in an attentional network.

Adult↗
PubMed1992

Neurotoxicity of solvent mixtures in spray painters. II. Neurologic, psychiatric, psychological, and neuroradiologic findings.

A multidisciplinary cross-sectional study was performed to examine the chronic neurotoxicity of organic solvents. Participating in the study were 105 persons employed as spray painters and having long-term solvent exposure (10-44 years) and a control group consisting of 58 construction workers, electricians, and plumbers without occupational contact to solvents. Samples were matched for age, preexposure intelligence level, occupation, and socioeconomic status. After controlling for potentially non occupational confounding factors (neuropsychiatric diseases, metabolic disorders, high blood pressure, alcohol intake) 83 spray painters and 42 controls were entered finally into the study. The evaluation included work history, self-rating questionnaire, neurologic investigation, psychiatric analysis using the Present State Examination (PSE), psychological testing, and computerized axial tomography (CAT) of the brain. Physical and neurologic examinations demonstrated no case of overt disorders of the central or peripheral nervous system. An important result of the psychiatric analysis was that the syndromes "special features of depression" and "loss of interest and concentration" occurred significantly more frequently among spray painters than among controls. Further analyses demonstrated an association with chronic exposure over 30 years and repeated acute neurotoxic effects during solvent exposures. Neither psychological nor performance tests demonstrated any statistically significant differences in the performance sets after adjustment according to premorbid intelligence level; this finding supports the presumption of only a low grade of mental dysfunction. Correlation analyses indicated a relationship between subjective health complaints and long-term solvent exposure; however, the effect of age cannot be completely ruled out.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The early course of atypical depression.

The early course was studied of 29 atypical depressives with first onset of affective disorder not otherwise specified in DSM-III-R. Psychopathology was not stable over time in all patients, with some showing bipolar disorder or melancholia.

Adolescent↗
PubMed1991

Effects of sleep deprivation on the limbic system and the frontal lobes in affective disorders: a study with Tc-99m-HMPAO SPECT.

We studied 10 patients with melancholia before and after sleep deprivation and 8 controls with Tc-99m-hexamethylpropylenamineoxime (HMPAO) single photon emission computed tomography (SPECT). All depressed subjects showed relative hypoperfusion in the left anterolateral prefrontal cortex under both conditions. Only responders showed relative hyperperfusion in parts of the limbic system and a reduction of blood flow in these regions after sleep deprivation.

Adult↗
PubMed1990

[Treatment with nootropic drugs].

The effectiveness of nootropic agents (cerebroactive substances) is still under controversial discussion. Confusion occurs owing to the fact that effectiveness tests are undertaken on quite different levels ranging from in vitro assays to observations of day-to-day living. Methods of testing the effectiveness of cerebroactive substances are presented, with consideration being given to the recommendations of the experts.

Aged↗