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Biomedical subjects

H M Emrich

Publications and source records attributed to H M Emrich.

At least 19 recordsLinked to original sources
PubMed1999

Effects of fentanyl and low doses of alcohol on neuropsychological performance in healthy subjects.

The effects of the opioid fentanyl and low doses of alcohol on neuropsychological functions in healthy volunteers were measured. Twenty-four healthy male volunteers participated in this study. Two randomised placebo-controlled cross-over trials were conducted. In group 1, 6 subjects received fentanyl (0.2 microgram/kg body weight) in the order of fentanyl/placebo and 6 subjects in the order of placebo/fentanyl. Group 2 received alcohol in a similar procedure by continuous intravenous infusion, leading to a blood alcohol concentration (BAC) of 0.03%. Impairment was measured via different neuropsychological tests. The results indicate that fentanyl in concentrations commonly used in out-patient surgical procedures produces pronounced cognitive impairment (auditory reaction time, signal detection, sustained attention, recognition) in comparison to placebo. After application of low doses of alcohol (BAC 0.03%) only visual reaction time was impaired in comparison to placebo.

Adult↗
PubMed1998

A viro-psycho-immunological disease-model of a subtype affective disorder.

Borna Disease Virus (BDV) infections are widespread in animal species. This neurotropic, negative and single-stranded enveloped RNA virus spreads via axonal and transsynaptic pathways quite specifically into olfactoric and limbic structures. The symptoms in BDV-infected animals range from unapparent or subtle clinical manifestations to fatal neurological disorders. The severe and fulminant course of the infection, which is often accompanied by neurobehavioral and "emotional" disturbances, occurs sporadically and, at least in experimentally infected animals (rats), is thought to be mediated by immunopathology. Increases in serum-BDV antibodies have also been detected in neuropsychiatric patients. In addition, viral antigen and viral RNA have been observed in acutely ill major depressive patients, leading to the conclusion that BDV was causally related to psychiatric disorders, in particular to affective disorders. A number of studies have meanwhile furnished evidence of abnormal immune functions in mentally ill patients. In addition, stress has been shown to decrease immune responses to viral infections. On the basis of these findings it is hypothesized that human BDV infection represents a co-factor in the development or course of psychiatric diseases. Stress may cause immunosuppression and thus induce activation of persisting BDV in the limbic system, resulting in an inflammatory reaction of these structures. These neuropathological changes might influence the serotonergic or dopaminergic neurotransmitter systems. In addition, a specific affinity of BDV structural elements for aspartate and glutamate receptors in the hippocampal formation might directly induce an imbalance of these transmitter system interactions, causing affective and behavioral disturbances. The possible interactions between stress-induced immunosuppression, BDV infection and affective disorders in humans, and the theoretical and clinical aspects of this concept are discussed.

Animals↗
PubMed1998

Lack of psychotomimetic or impairing effects on psychomotor performance of acamprosate.

The possible effects on psychomotor performance, concentration, attention, and mood of acamprosate (calciumacetylhomotaurinate) were assessed using a randomized, double-blind, cross-over, placebo-controlled design involving 12 healthy male volunteers. Acamprosate 2 g daily per os or placebo was administered for seven days and separated by washout intervals of at least 21 days. Objective tests evaluated psychomotor functions (simple reaction time measurement, binary choice reaction test, computerized visual searching task, sustained attention test). Mood was assessed using the Beck Depression Inventory and the Beschwerde-Liste to assess subjective physical impairment. Additionally, a visual 3-D illusion paradigm was applied to measure the psychotomimetic effect. A dose of acamprosate of 2 g/day for seven days was free of any significant effects on mood, concentration, attention, psychomotor performance and did not produce any subjective sedation, excitation or psychotomimetic effects.

Acamprosate↗
PubMed1998

Combined treatment of schizophrenic psychoses with haloperidol and valproate.

In accordance with a previous study of adjuvant effects of the anticonvulsant carbamazepine (CBZ) on the neuroleptic treatment of schizophrenic psychoses, the effects of valproate (VPA) were tested in a randomly assigned double-blind, placebo-controlled study. Apart from a (statistically nonsignificant) psychopathological deterioration following discontinuation of VPA while on continuous neuroleptic mediation after four weeks and a statistically significant effect on "hostile belligerence", no overall therapeutic effects of the combination of haloperidol (HPD) with VPA were observed under controlled conditions. Unlike the results with CBZ, concomitant use of VPA led to an even higher consumption of haloperidol and biperiden and to a higher rate of extrapyramidal symptoms compared with the corresponding placebo group, although these differences did not attain statistical significance. In regard to use of the sedative neuroleptic chlorprothixene, there was a trend toward lower doses in the VPA group than in the placebo group. From these results, adjuvant effects like those of carbamazepine in the neuroleptic treatment of schizophrenic psychoses could not be confirmed for valproate in the present study. However, the trend toward lower doses of sedative medication and observed effects on "hostile belligerence" may indicate sedative and/or antimanic properties of valproate which have recently been demonstrated in several controlled studies.

Adult↗
PubMed1998

Cannabinoid/anandamide system and schizophrenia: is there evidence for association?

Cognitive impairments during psychotic episodes are assumed to be caused not only by one single putative classical neurotransmitter dysfunction but also to be due to an impaired equilibrium of the interaction between different neurobiological generators of cognitive processes. Here, the perceptual abnormalities induced by psychotogenic agents play a major role as tools for understanding model psychoses. The recently discovered cannabinoid receptor system with its endogenous ligand anandamide can be regarded as an extremely relevant regulation system, a dysfunctionality of which may explain at least one subtype of endogenous psychoses. The present paper discusses the possible associations between the endogenous anandamide/cannabinoid system and schizophrenic psychoses. Neuropsychological experiments with the 3-D inversion paradigm were performed in healthy volunteers intoxicated with delta9-Tetrahydrocannabinol (delta9-THC). The 3-D inversion paradigm represents a visual illusion of binocular depth perception. Such an inversion occurs in many cases, especially when objects with a higher degree of familiarity (e.g. photographs of faces) are displayed. It is assumed that cognitive factors override the binocular disparity cues of stereopsis. We tested the hypothesis that, during psychotic and related prepsychotic states, the human CNS is unable to correct implausible perceptual hypotheses. Our study provides evidence of strong similarities between data acquired from patients, suffering from productive schizophrenic psychoses and delta9-THC-intoxicated healthy volunteers, as concerns disturbances in the internal regulation of perceptual processes.

Arachidonic Acids↗
PubMed1998

[Perception, mimesis and consciousness].

Questions as to the fundamentals of "consciousness" are envisaged, first of all, from the viewpoint of quantifying experiments on visual perception in humans, focussed on "internal censorship", the role of intrapsychic mechanisms processing and correcting perception, and secondly based on recent theories on "mimesis" in the sense of R. Girard's concept of psychosocial transfer of aims and values between humans. The paper demonstrates a convergence between these two strategies of understanding, pointing to the view that "consciousness" may be interpreted as the performance of the intrapsychic "translation" between "cognitive" and "assessing" (or "valuating") emotional processes.

Consciousness↗
PubMed1998

Cannabinoids: possible role in patho-physiology and therapy of Gilles de la Tourette syndrome.

High densities of cannabinoid receptors were found in the basal ganglia and hippocampus, indicating a putative functional role of cannabinoids in movement and behaviour. Anecdotal reports suggested beneficial effects of marijuana in Tourette's syndrome (TS). We therefore interviewed 64 TS patients with regard to use of marijuana and its influence on TS symptomatology. Of 17 patients (27%) who reported prior use of marijuana, 14 subjects (82%) experienced a reduction or complete remission of motor and vocal tics and an amelioration of premonitory urges and obsessive-compulsive symptoms. Our results provide more evidence that marijuana improves tics and behavioural disorders in TS. It can be speculated that cannabinoids might act through specific receptors, and that the cannabinoid system might play a major role in TS pathology.

Adolescent↗
PubMed1998

The effects of tetrahydrocannabinol on the recognition of emotionally charged words: an analysis using event-related brain potentials.

The effects of synthetic tetrahydrocannabinol (THC) on event-related brain potentials (ERPs) were assessed in 19 healthy male volunteers while they performed a visual continuous word recognition task. The study used a double-blind cross-over design. Specifically, word lists were manipulated to contain an equal number of emotionally neutral, negative, and positive words. Most words were repeated after several intervening items with the subject's task to classify each word as old (previously seen) or new. Behaviorally, a decrease in recognition rate was observed under THC but no influence of the emotional charge of a word on recognition rate was seen. The ERPs showed a typical difference between old and new words taking the form of an enhanced positivity for old words beginning 250 ms poststimulus. The effects of THC were confined to the positive words, for which an enhancement of the positivity to the old words was seen. This effect was interpreted in terms of a congruity of the drug-induced mood state and the material to be recognized. The dissociation between ERPs and behavioral indices suggested that the former primarily reflect implicit memory processes.

Adult↗
PubMed1998

The use of anticonvulsants to augment antidepressant medication.

Combination therapy that couples classical antidepressants with other psychoactive compounds is one of the major therapeutic strategies in therapy-resistant depression. The authors review reports on the antidepressive effects of the mood stabilizers carbamazepine and valproate and focus on the pharmacodynamic and clinical aspects of combining these compounds with antidepressant drugs. In addition, a pivotal study (N=10 outpatients) demonstrates the use and efficacy of a low-dose combination therapy of carbamazepine and amitriptyline. It is concluded that low-dose combination of classical antidepressants and mood stabilizers appears to be well tolerated and highly effective.

Adult↗
PubMed1998

[Therapy of bipolar affective illnesses with valproate. A review of the literature].

This paper gives an overall review of the literature since 1980 on the use of valproate in bipolar affective disorders. Randomised comparative studies definitely demonstrate that valproate proves superior in comparison with placebo and equivalent in comparison with lithium in the treatment of acute manic episodes. A series of open studies indicates a reduction in frequency and intensity of manic and depressive episodes with the long-term administration of valproate suggesting efficaciousness in the prophylaxis of bipolar affective disorders. Details on dosage, side effects and potential interactions with this group of patients are presented. Valproate constitutes a further valuable and well tolerated alternative to lithium, antipsychotic agents and carbamazepine not only in acute therapy of manic episodes but also in prophylactic treatment of patients with bipolar psychosis.

Anticonvulsants↗
PubMed1997

[Pro-psychotic change of binocular depth inversion by sleep deprivation].

Binocular depth inversion represents an illusion of visual perception. Such inversion does not occur in all cases, especially when objects with a higher degree of familiarity (e.g. photographs of faces) are displayed. Cognitive factors are assumed to override the binocular disparity cues of stereopsis. We tested the hypothesis that during sleep deprivation the human CNS is unable to correct the implausible perceptual information. Measurements of binocular depth inversion in perception of 3D objects were taken in sleep-deprived medical staff and healthy volunteers. The binocular depth inversion scores were highly elevated in the sleep-deprived group in comparison to the healthy volunteers. The data demonstrate a strong impairment of binocular depth inversion after sleep deprivation and support the view that sleep deprivation may be accompanied by a disorganisation of the interaction between sensory input and generation of perceptual hypotheses.

Adult↗
PubMed1997

Towards a cannabinoid hypothesis of schizophrenia: cognitive impairments due to dysregulation of the endogenous cannabinoid system.

Cognitive impairments during psychotic episodes are assumed to be caused not only by one single putative classical neurotransmitter dysfunction but also by an impaired equilibrium of the interaction between different neurobiological generators of cognitive processes. Herein, the perceptual abnormalities induced by psychotogenic agents play a major role as tools for the understanding of model psychoses. The recently discovered cannabinoid receptor system with its endogenous ligand anandamide can be regarded as an extremely relevant regulator system, a dysfunctionality of which may explain at least one subtype of endogenous psychoses. Neuropsychological results (three-dimensional inversion illusion) in delta 9-tetrahydrocannabinol-intoxicated normal volunteers exhibit strong similarities with data acquired from patients suffering from productive schizophrenic psychoses, regarding disturbances in internal regulation of perceptual processes. The relevance of this finding to a general cognitive dysfunction concept of schizophrenic psychosis is discussed.

Adult↗
PubMed1996

Visual 3D illusion: a systems-theoretical approach to psychosis.

Binocular depth inversion represents an illusion of visual perception. Such an inversion does not occur in all cases, especially when objects with a higher degree of familiarity (e.g. photographs of faces) are displayed. Cognitive factors are assumed to override the binocular disparity cues of stereopsis. We tested the hypothesis that during psychotic and similar states the human CNS is unable to correct the implausible perceptual hypothesis. Measurements of binocular depth inversion in perception of 3D objects were performed in schizophrenic patients (n = 13), in patients with alcohol withdrawal (n = 10), in sleep-deprived medical staff (n = 10) and in healthy volunteers (n = 41). The binocular depth inversion scores were highly elevated in the patient group and in the sleep-deprivated medical staff in comparison with healthy volunteers. The data demonstrate that impairment of binocular depth inversion reflects a common final pathway, characterized by an impairment of adaptive systems regulating perception.

Adult↗
PubMed1995

Effects of flumazenil on recovery sleep and hormonal secretion after sleep deprivation in male controls.

The effects of flumazenil, a benzodiazepine antagonist, on the sleep electroencephalogram (EEG) and neuroendocrine secretion in early morning recovery sleep (0500-0800 hours) following sleep deprivation (SD; 2300-0500 hours) were studied in seven healthy men. SD induced an increase in slow wave sleep (SWS), a decrease in sleep onset latency (SOL), an enhancement of EEG delta and theta power in non-rapid-eye-movement sleep, an increase in plasma human growth hormone (GH) concentration, and a decrease in plasma cortisol levels in recovery sleep (0500-0800 hours). Plasma GH, but neither plasma cortisol nor adrenocorticotrophic hormone (ACTH) concentration was attenuated during SD as compared to sleep (2300-0445 hours). The administration of flumazenil (3 x 1 mg intravenously) during recovery sleep resulted in an inhibition in SWS, an increase in stage 2 sleep, a selective reduction in delta and theta power, and a tendency to prolongation of SOL. Plasma GH concentration was decreased but plasma cortisol and ACTH remained unaffected. Since the SD-induced changes in sleep EEG and plasma GH secretion were antagonized by flumazenil, it is suggested that electrophysiological and hormonal effects of SD are mediated at least in part through GABAergic mechanisms.

Adrenocorticotropic Hormone↗
PubMed1995

[The emotional self with reference to neurotransplantation].

From a systems-theoretical point of view the concept of the "self" is represented and discussed in relation to phenomena of emotion. The question is raised as to whether structural changes of the brain induce changes of the "emotional self" and thereby induce changes of personal identity. The philosophical and neurobiological implications of these considerations are discussed in relation to transplantation of neuronal cells. The hypothesis is discussed that neuronal transplantation has to avoid the transfer of intact neuronal tissue and should be restricted to transfer of isolated cells, since otherwise parts of other neuronal "selves" might be transmitted.

Brain Mapping↗