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Biomedical subjects

Hinderk M Emrich

Publications and source records attributed to Hinderk M Emrich.

At least 19 recordsLinked to original sources
PubMed2006

Disturbances of visual information processing in early states of psychosis and experimental delta-9-tetrahydrocannabinol altered states of consciousness.

Recent data on alterations of the endogenous cannabinoid system in schizophrenia have raised the question of its functional role in this disease. The psychoactive compound of Cannabis sativa, delta-9-tetrahydrocannabinol (Delta9-THC), has been shown to induce psychotic symptoms, but it is unknown to what extend prodromal states of psychoses are reflected by these experimental approaches. This study compares four groups of subjects: antipsychotic-naïve patients suffering from acute paranoid schizophrenic or schizophreniform psychosis (SZ), patients in the prodromal state (IPS), healthy controls without any pharmacological intervention (HC) and a second group of healthy volunteers who were orally administered synthetic Delta9-THC (Dronabinol) (HC-THC). Neither SZ and IPS nor HC received the experimental drug. All subjects were assessed using the Brief Psychiatric Rating Scale (BPRS) and the Binocular Depth Inversion Illusion Test (BDII). The latter represents a sensitive measure of impaired visual information processing that manifests in various experimental and naturally occurring psychotic states. BDII values were well comparable in SZ, IPS and HC-THC, and all groups differed significantly to HC. The BPRS revealed no significant difference between HC-THC and IPS while both were significantly different from SZ and HC, respectively. Our results suggest that Delta9-THC-induced altered states of consciousness may serve as a useful tool for modeling psychotic disorders, particularly their prodromal states. Furthermore, they provide insight into the perceptual and psychopathological alterations induced by Delta9-THC, which is essential for the understanding of the pro-psychotic effects of herbal cannabis preparations with highly enriched Delta9-THC content.

Acute Disease↗
PubMed2006

Feasibility of central cannabinoid CB1 receptor imaging with [124I]AM281 PET demonstrated in a schizophrenic patient.

We studied central cannabinoid CB1 receptors in a schizophrenic patient using the pyrazole derivative AM281 labelled with the positron-emitting nuclide iodine-124. A dynamic positron emission tomography (PET) acquisition with simultaneous blood sampling was performed up to 1.5 h post-injection. The classical Logan plot analysis was applied to generate a three-dimensional map of distribution volume (DV). The map was spatially normalised into the Montreal Neurological Institute stereotactic space. Using a volume of interest (VOI) template, mean values of DV were extracted from multiple grey matter regions and white matter (as a reference). As a measure of regional receptor availability, ratios of DV in grey matter to DV in white matter minus one (DVR-1) were calculated. The highest receptor binding was observed in the striatum and the pallidum (DVR-1: 0.35-0.37). Binding in basal ganglia regions was lower on the left than the right side. Moderately high binding was seen in the frontal cortex (0.22), the temporal cortex (0.18) and the cerebellum (0.15). In conclusion, 124I-AM281 PET can be used to reveal areas with prominent CB1 receptor binding. Nevertheless, limited image contrast and relatively high radiation exposure (physical half-life of 124I: 4 days) have to be taken into account. Asymmetric receptor binding may possibly reflect pathologic changes in schizophrenia.

Brain↗
PubMed2006

[Screening for major dissociative disorders with the FDS, the German version of the Dissociative Experience Scale].

UNLABELLED: The prevalence of major dissociative disorders (dissociative identity disorder, DID and similar forms of dissociative disorder not otherwise specified, DDNOS) in clinical samples is about 5 %. Despite their frequency, major dissociative disorders are often overseen for a long time. Screening-scales have proved to be effective to support clinical diagnosis. The aim of this study was to test, whether the Fragebogen für dissoziative Symptome (FDS), the German version of the Dissociative Experiences Scale (DES), differentiates between patients with dissociative disorders, non-dissociative disorders and non-clinical controls. Additionally, an optimal FDS-cutoff for a more detailed differential-diagnostic evaluation of the dissociative symptomatology should be identified. 150 participants with DID (group DID: n = 44), DDNOS (DDNOS: n = 22), posttraumatic disorders (TRAUMA: n = 20), other non-dissociative disorders (non-TRAUMA: n = 34) and non-clinical controls (KG: n = 30) completed the FDS. In the five diagnostic groups, mean values were calculated and compared for the FDS, DES and FDS-20. Via receiver-operating-curves the cutoff-scores, which differentiated best between participants with and without major dissociative disorders, were identified. FDS, DES and FDS-20 differentiate significantly between patients with and without major dissociative disorders. For all scales, there were significant differences between the diagnostic groups, with mean-scores decreasing continuously from the groups DID to DDNOS and TRAUMA. Between the groups non-TRAUMA and KG tendencies were found in the predicted direction. The optimal cutoff-scores to differentiate between participants with and without major dissociative disorders were 13 (FDS/FDS-20) and 15 (DES). Using these cutoff-scores, at least 90 % of the patients with major dissociative disorders could be identified correctly (sensitivity). The specifity of the scales was 0.89 to 0.90. CONCLUSION: Screening for major dissociative disorders with the FDS, DES and FDS-20 allows to identify patients with or without major dissociative disorders correctly in about 90 % of the cases. Therefore, the FDS should be used routinely in psychiatric and psychotherapeutic clinics and practices to identify high risk patients. Such a procedure would be an important step towards an improvement of the diagnostic and therapeutic care of patients with major dissociative disorders, which is still often unsatisfactory at present.

Adolescent↗
PubMed2005

Serotonin transporter binding in Tourette Syndrome.

Recent studies provided evidence for an involvement of the dopaminergic system in the pathophysiology of Tourette Syndrome (TS). However, little is known about possible impairment of other neurotransmitter systems. In obsessive-compulsive disorder (OCD), a common comorbidity in TS, it is suggested that the serotonergic system plays a major role in the pathogenesis. We, therefore, used [I-123]2[beta]-carbomethoxy-3[beta]-(4-iodophenyl)tropane ([123I]beta-CIT) and single photon emission computed tomography (SPECT) to investigate serotonin transporter (SERT) binding capacity in 12 patients with TS with various degrees of associated obsessive compulsive behaviour (OCB) and 16 age-matched healthy controls. Binding ratios in TS patients not receiving serotonin reuptake inhibitors (SSRI) (n=8) were significantly reduced compared to age-adjusted ratios from normal controls (2.8 versus 3.2, p=0.003). Treatment with SSRI resulted in a significant reduction of SERT availability. Performing linear regression analysis for this small group, SSRI-free patients indicated trends for a negative correlation between [123I]beta-CIT binding on SERT and OCB (r=-0.78, p=0.023) as well as complex motor tics (r=-0.68, p=0.064). In healthy controls, but not in the TS group, we found an age-related decline in SERT binding capacity (0.28% decrease per year, p=0.038). Our data are in agreement with previous results suggesting an impairment of the serotonergic system in TS. It can be speculated that the reduction in SERT binding capacity is associated with the degree of comorbid OCB.

Adult↗
PubMed2005

Effects of different subanesthetic doses of (S)-ketamine on neuropsychology, psychopathology, and state of consciousness in man.

This is the first neuropsychological study using the S-enantiomer of the noncompetitive N-methyl-D-aspartate antagonist ketamine. In 2 randomized placebo-controlled trials we studied effects of two different doses of (S)-ketamine (low dose/high dose) on neuropsychological functions and psychopathology in 12 healthy male volunteers. Impairment was measured via standardized neuropsychological tests. Results indicate that both subanaesthetic doses produce only nonsignificant impairment in most of the tasks. Tasks involving divided and sustained attention as well as scores for objective and subjective psychopathology show significant impairment in a dose-dependent manner. Implications of these findings for the neuropsychology of attention and schizophrenia are discussed.

Adult↗
PubMed2005

Ecstasy (MDMA) mimics the post-orgasmic state: impairment of sexual drive and function during acute MDMA-effects may be due to increased prolactin secretion.

Methylenedioxymethamphetamine (MDMA or "Ecstasy") is a major stimulant drug of abuse worldwide. MDMA produces euphoria, enhances interpersonal communication and feelings of closeness with others. In contrast to the induced emotions of affection and sensual enhancement, clinical studies show that it impairs sexual drive and functioning. In drug-free humans, sexual stimulation with orgasm induces a pronounced secretion of prolactin, which may mediate the post-orgasmic state. The phenomenological features of the psychological state induced by MDMA show some similarities with features of the post-orgasmic state. In addition, MDMA also induces a prominent increase of prolactin plasma levels with a similar time kinetic compared to the post-orgasmic prolactin increase. Here, we present the hypothesis that the impairment of sexual parameters after MDMA may be mediated by increased prolactin.

N-Methyl-3,4-methylenedioxyamphetamine↗
PubMed2005

Sex hormones in psychotic men.

For women at risk to develop schizophrenia, estradiol has been postulated to constitute a protective factor. Women suffering from psychotic disorders have accordingly been found to exhibit lower estradiol levels than controls. Our aim was to study gonadal function in psychotic men to determine the gender specificity of these observations, as available data in men are more scarce and conflicting and largely disregarded estradiol. Serum hormone levels were examined in 34 men admitted consecutively for an acute exacerbation or first onset of schizophrenia in a blinded prospective design. Subjects with current affective disorder including manic episode, concomitant substance abuse or severe medical illness were excluded. A control group of 34 healthy male blood donors was recruited. As compared to matched controls, acutely admitted men suffering from schizophrenia exhibited significantly lower serum levels of estradiol, oestrone, testosterone and free testosterone. Although results have to be regarded as preliminary, acute exacerbation of schizophrenia in men seems to be associated with low serum oestrogen and androgen levels. The oestrogen hypothesis postulating a protective action of estradiol concerning schizophrenia for women might well be valid for both genders. However, future research is needed before clinical applications are justified.

Adult↗
PubMed2005

Oxidative stress during treatment with first- and second-generation antipsychotics.

Neurotoxicity of first-generation antipsychotics (FGAs) may be involved in lipid peroxidation, which is the pathogenesis of extrapyramidal symptoms, including tardive dyskinesia (TD). Blood samples at day 0, 7, and 21 drawn from patients taking antipsychotics were analyzed for malondialdehyde (MDA) in plasma, a marker of lipid peroxidation, by high-performance liquid chromatography. Of 115 patients enrolled, 92 patients completed the study. Most MDA levels were within normal ranges (<1.0 micromol/liter). Malondialdehyde levels in patients receiving clozapine (p = 0.002), quetiapine (p = 0.003), amisulpride (p = 0.008), and risperidone (p = 0.008) were significantly lower than within the first generation antipsychotic group. The authors conclude that lipid peroxidation is significantly higher in treatment with FGAs.

Adolescent↗
PubMed2004

[123I]AM281 single-photon emission computed tomography imaging of central cannabinoid CB1 receptors before and after Delta9-tetrahydrocannabinol therapy and whole-body scanning for assessment of radiation dose in tourette patients.

BACKGROUND: The cannabinoid CB1 receptor agonist Delta9-THC has been suggested for treatment of Tourette syndrome (TS). Based on animal studies, the CB1 antagonist [123I]AM281 (N-(Morpholin-4-yl)-1-(2,4-dichlorophenyl)-5-(4-[123I]iodophenyl)-4-methyl-1H-pyrazole-3-carboxamide) has been proposed for single photon emission computed tomography (SPECT) in humans. Our aims were to 1) evaluate specific binding of [123I]AM281 to CB1 receptors in TS patients and 2) assess radiation exposure associated with the use of AM281 labeled with 123I for SPECT and 124I for positron emission tomography. METHODS: We employed [123I]AM281 in six TS patients before and after Delta9-THC treatment. Dynamic SPECT, plasma measurements (including metabolite analysis with thin layer chromatography), and whole-body imaging were performed. Regions of interest derived from magnetic resonance images were used to extract from SPECT uptake in an area with high CB1 density (lentiform nuclei) and reference regions. Specific over nonspecific partition coefficients V3" were calculated. Whole-body images were carried out for dosimetric analysis. Data obtained with [123I]AM281 were used to predict doses from [124I]AM281. RESULTS: Mean V3" ranged from .19 to .31 and did not change significantly after Delta9-THC treatment. Nevertheless, in the only patient with a marked clinical response, V3" clearly declined. Thin layer chromatography revealed biexponential kinetics of tracer metabolism; about 60% remained nonmetabolized after 3 hours. Effective doses of .011 mSv/MBq for [123I]AM281 and .34 for [124I]AM281 were computed. CONCLUSIONS: This study suggests that specific binding of [123I]AM281 to CB1 receptors can be detected in patients using SPECT. Radiation exposure with [123I]AM281 is low; that with [124I]AM281 is higher but acceptable for single investigations.

Adult↗
PubMed2004

Target evaluation processing and serum levels of nerve tissue protein S100B in patients with remitted major depression.

Selective attention processes (N2 and P3 components of event-related potentials (ERPs)) have been shown to be impaired in depressed patients but findings have been mixed. Part of this variability might be explained by neurobiological factors. ERPs (Go/Nogo paradigm) were investigated in patients with remitted major depression in relation to S100B. S100B, an astroglial protein with neuroplastic properties, has been shown to be increased in depression. Its pathophysiologic role in depression, however, is not yet sufficiently understood. Patients with increased S100B serum levels (n=6) showed a normal N2- and P3-amplitude in contrast to a reduced N2- and P3-amplitude in patients with normal S100B serum levels (n=6). These findings provide evidence of a correlation between S100B levels and attentional processes in patients with recurrent depression and further substantiate S100B's role as a marker in the course of affective disorders.

Attention↗
PubMed2004

[The original paradigm of dependence - historical and cultural aspects].

Repeated drunkenness became a contradiction in terms of a healthy and rational life style in the context of the Enlightenment in the 18th century. Corresponding to the self-referential understanding of man as an independent and rational being repeated drunkenness could not longer be understood as a conscious decision or a vice. The central point of the new paradigm of dependence was the installation of a special urge by a specific chronic chemical traumatization. But this original paradigm also required the acceptance of the human individual as a depth-structured being and shows influence by the Brownianism, therefore it is also an unspecific concept. This understanding corresponds with the modern anthropology, in which the human being is understood two-fold: on the one hand his consciousness and mind, on the other hand his unconsciousness, body and world around.

Alcoholic Intoxication↗
PubMed2003

Effect of sildenafil (Viagra) on cerebral blood flow velocity: a pilot study.

Sildenafil (Viagra) is a selective inhibitor of the cyclic guanosine monophosphate (cGMP) specific phosphodiesterase 5 (PDE5) used for the oral treatment of male erectile dysfunction due to vasodilation. However, assessment of direct effects of sildenafil on cerebral arteries is unknown. The aim of this present experiment is to measure the possible changes in blood flow velocity of the middle cerebral artery after the administration of sildenafil and a placebo. Blood-flow velocity changes of the middle cerebral artery were measured before and 1 to 2 h after the administration of the drug. Neither the intake of sildenafil nor the application of placebo resulted in any significant changes in blood flow velocity of the right middle cerebral artery. The next step for future experiments will be in vitro measurement of the diameters of the cerebral arteries under the influence of sildenafil and in vivo measurement of carbon dioxide and cerebral blood flow velocity during sexual stimulation after sildenafil intake instead of under resting conditions.

Adult↗
PubMed2003

On the function of groaning and hyperventilation during sexual intercourse: intensification of sexual experience by altering brain metabolism through hypocapnia.

Sexual arousal is accompanied by some typical physiological reaction patterns. Another typical feature of sexual intercourse is involuntary sound production implying in its more intense forms acceleration of breathing (hyperventilation). Up to now no study examined spCO2 during intense sexual intercourse, but there is evidence that some degree of hyperventilation with its physiological consequences may often be induced during sexual intercourse. This article discusses implications of hyperventilation during sexual intercourse for alterations of consciousness and subjective experience in the light of recent studies of brain metabolic changes during states of hyperventilation. Groaning and hyperventilation are interpreted in this context as a psychophysiological mechanism to deepen states of sexual trance.

Brain↗
PubMed2003

Treatment of Tourette syndrome with delta-9-tetrahydrocannabinol (delta 9-THC): no influence on neuropsychological performance.

Previous studies provide evidence that marijuana (Cannabis sativa) and delta-9-tetrahydrocannabinol (Delta(9)-THC), the major psychoactive ingredient of marijuana, respectively, are effective in the treatment of tics and behavioral problems in Tourette syndrome (TS). It, therefore, has been speculated that the central cannabinoid receptor system might be involved in TS pathology. However, in healthy marijuana users there is an ongoing debate as to whether the use of cannabis causes acute and/or long-term cognitive deficits. In this randomized double-blind placebo-controlled study, we investigated the effect of a treatment with up to 10 mg Delta(9)-THC over a 6-week period on neuropsychological performance in 24 patients suffering from TS. During medication and immediately as well as 5-6 weeks after withdrawal of Delta(9)-THC treatment, no detrimental effect was seen on learning curve, interference, recall and recognition of word lists, immediate visual memory span, and divided attention. Measuring immediate verbal memory span, we even found a trend towards a significant improvement during and after treatment. Results from this study corroborate previous data suggesting that in patients suffering from TS, treatment with Delta(9)-THC causes neither acute nor long-term cognitive deficits. Larger and longer-duration controlled studies are recommended to provide more information on the adverse effect profile of THC in patients suffering from TS.

Adolescent↗
PubMed2003

Effects of acute alcohol withdrawal on memory performance in alcohol-dependent patients: a pilot study.

Studies on the neuropsychological performance in detoxified alcoholic patients often begin by acknowledging that there is a cognitive impairment to be found. Only little attention has been paid to date to the question as to how acute alcohol withdrawal might affect cognitive functions. Twenty-nine alcohol-dependent inpatients, nine in moderate alcohol withdrawal, treated with carbamazepine (group 1), 10 in mild alcohol withdrawal without pharmacological treatment (group 2), 10 in mild alcohol withdrawal with carbamazepine treatment (group 3) and 31 healthy subjects as controls (group 4) underwent repeated investigations using memory tests. The tests were performed on the first, third, seventh and fourteenth days of withdrawal. Immediate free recall of a word-list was impaired in the three patient groups in comparison with the control group on the 1st day. Thereafter no significant differences could be revealed between patients and controls. In a word-list recognition test the memory functions were not impaired in group 1 and group 2 in comparison with the control subjects. However, patients in group 3 showed impairment in this recognition test in comparison with the healthy subjects on the first and third days. The present study suggests that acute alcohol withdrawal impairs memory functions, especially free recall. This should be considered in treatment interventions in the early days of withdrawal.

Adult↗
PubMed2003

Tourette syndrome and obsessive-compulsive disorder: event-related brain potentials show similar mechanisms [correction of mechansims] of frontal inhibition but dissimilar target evaluation processes.

OBJECTIVES: Tourette Syndrome (TS) and Obsessive-Compulsive Disorders (OCD) share many clinical similarities and show a strong comorbidity. Current theories view a frontal-striatal dysfunction as the underlying cause of many clinical aspects of both disorders. This study sought to investigate mechanisms of conceptual integration and attention in both disorders. We hypothesized that the processing of stimuli with interfering aspects would be altered in a similar way while attentional mechanisms could differ. METHODS: Event-related brain potentials (ERPs) were recorded in a modified STROOP-paradigm in groups of TS and OCD patients and in a control group. The paradigm involved the presentation of color words in a range of different colors. The subjects had to respond to words of matching word content and color and to ignore mismatching stimuli. RESULTS: Incongruent stimuli elicited a frontal negative component ("N450") which was enhanced in amplitude and prolonged in latency in both patient groups. Matching stimuli evoked enhanced N2 and P3b components representing target evaluation mechanisms. The OCD group alone displayed a larger P3b amplitude in comparison to both other groups. CONCLUSIONS: The data are interpreted to indicate that frontal inhibitory mechanisms are altered alike in TS and OCD. In contrast, only the OCD group showed evidence for aberrant target evaluation.

Adolescent↗