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Biomedical subjects

O Benkert

Publications and source records attributed to O Benkert.

At least 73 records · Page 4Linked to original sources
PubMed1994

Functional properties of the brain during sleep under subchronic zopiclone administration in man.

Zopiclone, a non-benzodiazepine, has been shown to be efficient in the treatment of transient, short-term or chronic sleep disorders. Apart from its hypnotic effects zopiclone has anxiolytic, anticonvulsant and myorelaxant properties and is therefore hardly distinguishable from benzodiazepines. Dependence liability and discontinuation effects have been reported to be less pronounced. Therefore zopiclone seems to be a hypnotic drug which may cause fewer side effects than conventional benzodiazepines. From the electrophysiological point of view one requires from a hypnotic drug the induction of a physiological sleep pattern as well as no alterations of information processing by the brain. The aim of the present study was to investigate the subchronic effect of zopiclone medication on some functional properties of the sleep EEG in healthy subjects. In order to get better insight into the principles of information processing by the brain during sleep and its alterations under the influence of zopiclone we applied some tools from linear system theory to sleep EEG data. For this purpose we investigated late components of auditory and visual evoked potentials during different sleep stages and calculated from these the so-called amplitude-frequency characteristic of the brain. This function describes the relationship between an input and the output of the investigated system. The main advantage of this kind of analysis is that it enables one to detect functional differences during sleep stages. This information can hardly be obtained from conventional spectral analysis. As a result we could demonstrate that under subchronic zopiclone medication no quantitative or qualitative alterations of the functional sleep EEG properties concerning the transfer properties of the brain under auditory and visual stimulation were detectable.

Adult↗
PubMed1994

Adverse effects associated with the short-term treatment of panic disorder with imipramine, alprazolam or placebo.

Side effects play a significant role in the selection of drugs to be used in panic disorder/agoraphobia whose polyphobic symptomatology often includes a suspiciousness about taking drugs and a fear of undesired side effects which may lead to the refusal of treatment. The safety, side effects and patients' acceptance of alprazolam and imipramine versus placebo were evaluated in 1168 subjects with panic disorder/agoraphobia who had been enrolled in the second phase of the Upjohn World Wide Panic Study. Side effects that worsened over baseline to a greater extent with alprazolam than with imipramine and placebo were sedation, fatigue/weakness, memory problems, ataxia and slurred speech. In the imipramine group blurred vision, tachycardia/palpitations, insomnia, sleep disturbance, excitement/nervousness, malaise, dizziness/faintness, headache, nausea/vomiting and decrease in appetite were worse than in the other groups. In the placebo group the anxious symptoms were most prominent. The highest level of compliance was shown in the alprazolam-treated group and the lowest in the placebo-treated group. Strong predictors of side effects were not observed. If a side effect profile is known, it will be easier for a clinician to choose the right drug and the appropriate management by taking into account compliance, safety and efficacy in each patient under treatment. Further information about side effects in long-term maintenance treatment would be of great clinical pertinence in ensuring safety and enhancing patients' quality of life.

Adolescent↗
PubMed1994

Plasma levels of benperidol, prolactin, and homovanillic acid after intravenous versus two different kinds of oral application of the neuroleptic in schizophrenic patients.

Plasma levels of prolactin (PRL) and the butyrophenone neuroleptic benperidol (BPD) were closely followed 0 to 48 h after acute application of 6 mg BPD as intravenous injection, orally as liquid, and orally as tablets in 12 schizophrenic patients using a partially randomized cross over design. Drug concentrations showed application specific pharmacokinetic behavior with complete elimination within 48 h. All three applications led to a biphasic PRL response with pronounced initial plasma PRL peaks returning to baseline levels within 48 h. The results suggest that after acute neuroleptic challenge BPD plasma levels as low as 2-3 ng/ml can be sufficient for complete depletion of pituitary PRL stores. This initial peak was followed by a PRL plateau about twice above pretreatment values indicating doubling of the PRL synthesis and secretion independent of supraeffective actual BPD concentrations. The PRL plateau persisted as long as BPD concentrations were above those levels which triggered the initial PRL response. As compared with the time of maximum concentrations (tmax) for BPD, the PRL tmax was later after i.v. injection, equal after liquid application, and earlier after tablet administration leading to pronounced application specific differences in shape, direction, and position of resulting hysteresis curves. Plasma levels of homovanillic acid (HVA) were not affected by BPD treatment. The PRL and HVA levels registered after acute doses of BPD indicated that the hormone responses were most likely the result of acute depletion of PRL stores and subsequent stimulation of hormone synthesis whereas it seemed unlikely that dopaminergic activities were relevant.

Administration, Oral↗
PubMed1994

Effects of long-term treatment with the MAO-A inhibitor moclobemide on sleep EEG and nocturnal hormonal secretion in normal men.

Sleep EEG, nocturnal penile tumescence (NPT) and nocturnal hormone secretion were studied in four normal males during placebo, under up to 300 mg per day of moclobemide, the short-acting and reversible inhibitor of monoamine oxidase (type A), and after withdrawal. Under moclobemide, REM sleep was slightly suppressed. Drug cessation was followed by REM rebound. In contrast to REM sleep, NPT was not affected by the drug. The nocturnal cortisol concentration was elevated under moclobemide and this effect persisted after withdrawal. No influences on growth hormone, prolactin, testosterone, luteinizing hormone or follicle-stimulating hormone were found.

Adult↗
PubMed1994

Roxindole, a dopamine autoreceptor agonist, in the treatment of positive and negative schizophrenic symptoms.

Twenty schizophrenic inpatients with either predominantly positive or predominantly negative symptoms were treated with the dopamine autoreceptor agonist roxindole in prospective open clinical trials. There was no antipsychotic effect in the subgroup with positive symptoms, whereas the subgroup with negative symptoms, especially those with the residual type of schizophrenia, showed a moderate but significant 20% reduction in total scores on the Scale for the Assessment of Negative Symptoms.

Dopamine Agents↗
PubMed1993

Continuity and discontinuity of affective disorders and schizophrenia. Results of a controlled family study.

BACKGROUND: It is widely acknowledged that the genetic diatheses for schizophrenia and affective disorders are independent. However, there are increasing doubts about this classic view, and empirical evidence for a dichotomy of these two prototypes of functional psychoses is limited. A controlled family study of consecutive admissions was conducted to determine whether familial risks for schizophrenic (SCZ) and affective disorders were independent or overlapping. METHODS: Index probands met Research Diagnostic Criteria for SCZ (n = 146), schizoaffective (SA [n = 115]), bipolar (BP [n = 80]), or unipolar major depressive (UP [n = 184]) disorder. Comparison probands met Research Diagnostic Criteria for alcoholism (n = 64) or were sampled from the general population (n = 109). A total of 2845 first-degree relatives were blindly diagnosed from interview, informant, and/or record data, with direct interviews completed in 2070 (82% of living first-degree relatives). RESULTS: By Cox's proportional hazards analysis, SCZ, SA, BP, and UP disorders were familial, in that each group of relatives had an increased lifetime morbid risk (vs those with alcoholism and those from the general population) for the proband's diagnosis. The SCZ and BP disorders were transmitted independently: only probands with manic disorders (BP or SA-BP subtype) showed increased familial risks of BP disorder, and only probands with prominent SCZ features (SCZ or SA) showed increased familial risks of SCZ disorder. However, SCZ probands had an increased familial risk for UP disorder (as did SA, BP, and UP probands) and for the SA-UP subtype. Aggregation of depression in families of SCZ probands could not be explained by the subtype of depression, broad or narrow definition of SCZ disorder, presence or absence of history of depression in SCZ probands, whether onset of depression in a relative occurred before or after onset of a proband's SCZ disorder, or assortative mating. CONCLUSIONS: These data suggest that there could be a familial relationship between the predispositions to schizophrenia and to major depression. We discuss a number of alternative hypotheses about the nature of this possible relationship.

Adult↗
PubMed1993

Roxindole, a dopamine autoreceptor agonist, in the treatment of major depression.

Roxindole is a potent autoreceptor-"selective" dopamine agonist originally developed for the treatment of schizophrenic syndromes. The drug also inhibits 5-HT uptake and has 5-HT1A agonistic actions. In this open clinical trial 12 in-patients suffering from a major depressive episode (DSM-III-R) were treated with roxindole for 28 days in a fixed dosage of 15 mg per day. A reduction of at least 50% in HAMD-17 total scores was observed in 8 out of 12 patients after 4 weeks (mean HAMD-17 reduction of 56% in all patients), while 4 patients did not respond to roxindole treatment. Half of the patients showed a complete psychopathological remission (HAMD-17 < 8). Roxindole's onset of antidepressant action was remarkably rapid. Seven out of eight responders improved within the first 2 weeks of treatment (at least 50% decrease in HAMD-17 total score), and four patients were nearly asymptomatic within 1 week. Our results indicate that roxindole may possess potent antidepressant properties and that its efficacy should be further evaluated by double-blind controlled studies against reference drugs.

Adult↗
PubMed1993

Dopamine autoreceptor agonists in the treatment of schizophrenic disorders.

1. Synthesis and release of dopamine as well as firing rates of dopaminergic neurons are controlled by stimulation of autoreceptors via a negative feedback regulation. Investigations on therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia have yielded inconsistent results. 2. With respect to the dopamine hypothesis of schizophrenia, dopamine autoreceptor agonists have been tested in positive schizophrenic symptomatology in order to reduce the postulated excess of central dopaminergic activity. However, administration of selective dopamine autoreceptor agonists like talipexole or roxindole did not result in a significant improvement of psychopathological symptoms. 3. In negative schizophrenic symptomatology, a dopamine deficit rather than an excess has been hypothesized. Current evidence from open clinical trials suggests that dopamine autoreceptor agonists may produce a minor to moderate improvement of symptoms like affective flattening, depressed mood, alogia and avolition.

Dopamine Agents↗
PubMed1993

Differential effects of the enantiomers R(-) and S(+) oxaprotiline on major endogenous depression, the sleep EEG and neuroendocrine secretion: studies on depressed patients and normal controls.

The effects of the optically active enantiomers of oxaprotiline (OXP), R(-) OXP and S(+) OXP, on depressive symptomatology and the sleep EEG were investigated in two separate exploratory studies. In addition, the neuroendocrine profile of both compounds was characterized in normal controls. In the patients treated with a daily oral dose of 150 mg S(+) OXP we found a Hamilton depression score that decreased from 29.1 +/- 1.8 (SEM) on day 0 to 14.7 +/- 3.2 on day 28 (P < 0.01). Six patients were judged to be full responders (HAMD score 0-7 points), three were improved (HAMD score 8-15) and four were nonresponders (HAMD score > 16). The therapeutic effect achieved with 150 mg R(-) OXP daily was less pronounced: the HAMD score decreased from 27.8 +/- 2.5 on day 0 to 19.4 +/- 3.2 on day 28 (P < 0.05). There were two full responders, one improved patient and seven nonresponders. The sleep EEG scoring revealed a marked suppression of REM sleep among patients treated with S(+) OXP but not with R(-) OXP. In the normal controls, a single oral dose of 75 mg S(+) OXP prompted an increase in the secretion of cortisol and growth hormone, whereas 75 mg R(-) OXP did not. Neither enantiomer influenced the secretion of testosterone or prolactin.

Adult↗
PubMed1993

A comparison study of moclobemide and doxepin in major depression with special reference to effects on sexual dysfunction.

A double-blind parallel-group comparison study of moclobemide versus doxepin in 237 patients with major depression confirmed that moclobemide was equal in efficacy and better tolerated than doxepin. It was less sedating and caused fewer anticholinergic adverse events as measured by the UKU side-effect rating scale. Unexpectedly, moclobemide therapy more often than doxepin resulted in increased sexual desire. An exploratory analysis of UKU-measured symptoms of impaired sexual function prior to commencement of the study revealed that moclobemide more often than doxepin led to an improvement of reduced libido and impaired erection, ejaculation and orgasm. This finding is compatible with the assumption that there is a greater likelihood that the anticholinergic reuptake inhibitor doxepin has a higher risk of impairing sexual function than the non-anticholinergic RIMA moclobemide. A single case report of moclobemide-induced sexual hyperarousal supports the alternative assumption that moclobemide has a specific sexually stimulative effect in depression.

Adult↗
PubMed1993

Studies of nocturnal penile tumescence and sleep electroencephalogram in patients with major depression and in normal controls.

Nocturnal penile tumescence (NPT), sleep electroencephalogram and testosterone secretion were investigated in 25 nonmedicated male patients with an acute episode of major depression. Twelve patients were reassessed after a stable remission and withdrawal of antidepressants. Four of the 25 patients had no NPT activity during acute depression, but this was reversed after recovery. The area under the NPT curve increased after remission, whereas all other NPT variables remained unchanged. Nocturnal testosterone secretion was enhanced after recovery, whereas the sleep structure remained unchanged. The NPT findings for the depressed patients did not differ from those for a control group, even though the latter group was younger. Hence, there are no general NPT changes that could be used to separate depressed patients and normal controls. However, a lack of NPT seems to be a possible, reversible symptom of depression in men.

Adult↗
PubMed1993

[Panic disorder and vertigo. On the psychopathologic differentiation between neurologic and psychiatric disease].

Seventy-six in- and outpatients seeking help for complaints of dizziness in a neurological clinic were assessed by the Structured Clinical Interview for DSM III (SCID). Neurological assessment included electrophysiological and otological examination. We established criteria to differentiate between dizziness as a symptom of panic disorder and dizziness as a symptom of neurological illness. Criteria for dizziness as a symptom of panic disorder are: adverse life events before the onset of dizziness, current comorbidity with depression, a high number of vegetative symptoms typical for panic attacks, a specific cluster of symptoms and little evidence of a neurological illness. We conclude that patients with complaints of dizziness often suffer from anxiety disorders. Thus we describe a vestibular subtype and contribute to the classification of panic disorder.

Adult↗
PubMed1992

Differentiation between major and minor depression.

Though the concept of Major Depression was generated by clinicians using depressed inpatients as models, a polydiagnostic study in 600 psychiatric inpatients with heterogenous psychological disturbances revealed that all six competing operational definitions of Major Depression (including DSM-III-R and ICD-10) were too restrictive to serve as a general concept of depression. Another polydiagnostic study in 500 primary care outpatients showed that more than two-thirds of all non-chronic depressed cases were below the severity threshold of Major Depression: these patients are classified as Depression Not Otherwise Specified (NOS) by DSM-III-R. Loosening of the over-restrictive time criteria would broaden the concept of Major Depression so as to meet the requirements of a general concept of depression, while the definition of Minor Depression below the threshold of Major Depression would add to a reduction of cases of NOS Depression by more than 80%. For the evaluation of antidepressant drugs in outpatient samples, we propose that patients with these modified definitions of Major and Minor Depression be included, provided they meet a minimum severity criterion of 13 or more points on the Hamilton Depression Scale; four-fifths of the modified Major Depression group and one-third of the Minor Depression group do in fact meet this criterion.

Depression↗
PubMed1992

Nimodipine in acute alcohol withdrawal state.

The effect of the calcium channel blocker, nimodipine, in acute alcohol withdrawal was investigated in a randomized, placebo controlled, double blind study. Thirty-two male patients with a history of alcohol dependence according to DSM-III criteria, but no other substance abuse, were included. A new rating instrument which fulfilled theoretical test criteria was applied to determine the severity of the alcohol withdrawal state. The patients received nimodipine or a placebo on four separate occasions (4 x 60 mg) and, in addition, clomethiazole, according to a standardized procedure. Our investigation has shown that, in the first 48-72 h of alcohol withdrawal, both groups consumed similar amounts of additional clomethiazole medication. Thus, no significant effect of nimodipine on the acute alcohol withdrawal state could be demonstrated. There was some tendency for nimodipine to ameliorate psychosensory dysfunction.

Acute Disease↗
PubMed1992

Risperidone in the treatment of disorders with a combined psychotic and depressive syndrome--a functional approach.

In vitro receptor-binding profiles and in vivo pharmacological studies have shown risperidone to be a potent mixed serotonin-S2 dopamine-D2-like receptor antagonist. While anti-D2 activity may relate to the antipsychotic potency of neuroleptic drugs, an antidepressive efficacy of substances with anti-S2 activity has been suggested. In an open pilot-study, ten patients with schizodepressive disorders or a DSM-III-R diagnosis of psychotic major depressive episodes were treated with risperidone (2-10 mg/d) for six weeks. Weekly psychopathological evaluation was performed, including BPRS, SANS, SAPS, VAS scales, and AIMS and UKU for the assessment of side-effects. Generally, the psychotic syndrome (BPRS, SANS and SAPS) decreased markedly in all patients; seven patients also showed a clinically significant improvement of depressive symptoms (BPRS). Except for two patients who needed biperiden because of extrapyramidal side-effects, the tolerance of risperidone was good. The antipsychotic and antidepressive properties of risperidone shown in our pilot study are promising enough to merit full double-blind controlled trials for further evaluation of its therapeutic value in this broad spectrum of psychiatric disorders.

Adult↗
PubMed1992

Dopamine autoreceptor agonists in the treatment of schizophrenia and major depression.

Dopamine autoreceptor agonists reduce the firing rate, synthesis, and release of dopamine in dopaminergic neurons by means of a negative feedback mechanism via stimulation of autoreceptors. Moreover, dopamine autoreceptor agonists are able to stimulate supersensitive but not normosensitive postsynaptic receptors. For dopamine autoreceptor agonists, therapeutic effects by readjustment of excessive or deficient dopaminergic function have been postulated for positive and negative schizophrenic symptomatology as well as for subtypes of depressive disorders. Investigations on the therapeutic effects of autoreceptor-nonselective dopamine agonists in schizophrenia or depression have yielded inconsistent results. In order to reduce the excess of central dopaminergic activity postulated by the dopamine hypothesis of schizophrenia, dopamine autoreceptor agonists have been tested in open clinical trials in positive schizophrenic symptomatology. However, administration of selective dopamine autoreceptor agonists like talipexole or roxindole did not result in a significant improvement of positive psychotic symptoms. In negative schizophrenic symptomatology, a dopamine deficit rather than an excess has been hypothesized. Current evidence from pilot studies suggests that dopamine autoreceptor agonists like roxindole may produce a minor to moderate improvement of symptoms like affective flattening, depressed mood, alogia, and avolition, possibly by stimulation of supersensitive postsynaptic dopamine receptors. For certain subgroups of depression, a reduction of functional dopamine activity has been postulated. In an open pilot study in patients with a major depression, roxindole demonstrated antidepressive properties comparable to those of standard antidepressants, justifying further double-blind controlled trials against reference drugs.

Animals↗
PubMed1992

Schizoaffective disorder and affective disorders with mood-incongruent psychotic features: keep separate or combine? Evidence from a family study.

OBJECTIVE: This study investigated whether the distinction between schizoaffective disorder and affective disorders with mood-incongruent psychotic features as described in DSM-III-R is reflected by aggregation of schizophrenia in the families of probands with the former disorder and aggregation of affective disorders mainly among the relatives of probands with the latter type of disorders. METHOD: The probands were 118 inpatients with definite lifetime diagnoses of DSM-III-R schizoaffective disorder or a major mood disorder with incongruent psychotic features according to structured clinical interviews. Diagnostic information on 475 of the probands' first-degree relatives was gathered through direct interviews (with 80% of the living first-degree relatives) or the family history approach. The rates of affective and psychotic disorders among these relatives were then compared with those among the relatives of a comparison group of 109 interviewed individuals from the general population who were matched on sociodemographic factors to the inpatient probands. RESULTS: With regard to the familial aggregation of schizophrenia, the DSM-III-R distinction emerged as valid. However, the risk of unipolar affective disorders was enhanced in the families of all of the subgroups of patients studied. The unipolar/bipolar distinction in both DSM-III-R diagnostic groups was reflected by distinct patterns of bipolar disorders in the relatives. CONCLUSIONS: The results partly support the DSM-III-R dichotomy of schizoaffective disorder and affective disorders with mood-incongruent psychotic features. Although the differences between these two diagnostic groups were significant, the magnitude of the differences remained relatively modest.

Adult↗