Search results for "PAM"
showing 10 items of 1768 documents
Asymmetry in dopamine D2/3 receptors of caudate nucleus is lost with age
2007
Molecular and functional imaging techniques reveal evidence for lateralization of human cerebral function. Based on animal data, we hypothesized that asymmetry in dopamine neurotransmission declines during normal aging. In order to test this hypothesis, we measured dopamine D2/3 receptor availability with [18F]desmethoxyfallypride-PET (DMFP) in putamen and caudate nucleus (NC) of 21 healthy, right-handed males (24-60 years; 35+/-10). For volumetric analysis, high-resolution T1-weighted MR-images were obtained in 18 of the PET-subjects in order to assess possible age-related decreases in NC and putamen volume. The calculated DMFP binding potentials (BP) showed a right-ward asymmetry in NC of…
Roxindole, a dopamine autoreceptor agonist, in the treatment of major depression
1993
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…
Lisuride, a dopamine D2 receptor agonist, and anticraving drug expectancy as modifiers of relapse in alcohol dependence
2002
Due to a central role of dopamine in mediating ethanol intake and dependence, the authors tested lisuride, a dopamine D2 receptor agonist, for relapse prevention in alcoholics. Psychological and neuroendocrine determinants of outcome were also assessed within the study. This double-blind, placebo-controlled randomized study comprised 120 alcoholics who were subjected to an intend-to-treat analysis (ITT). After hospital detoxification, patients received an outpatient rehabilitation program and either the study medication or placebo for 6 months and follow-up for another 6 months without medication. Pharmacological and psychological effects on relapse and times to first drink were assessed us…
Altered benzodiazepine receptor sensitivity in alcoholism: a study with fMRI and acute lorazepam challenge.
2007
Previous studies suggested altered sensitivity of the GABA/benzodiazepine receptor system in alcoholic patients. Expanding on these findings, the present functional magnetic resonance imaging (fMRI) study aimed to assess whether a differential modulation of cognitive brain activation by an acute GABAergic drug challenge could be detected in patients with alcoholism. Eight detoxified male patients meeting DSM-IV criteria for alcohol dependence and nine healthy male control subjects were studied with fMRI while performing a 2-back working memory task. The fMRI scans were performed 1 h after intravenous administration of saline and again 1 h after 0.03 mg/kg lorazepam I.V. After saline, a task…
Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge
2005
Summary Objective To verify findings of an independently regulated anterior limbic alpha band source. Methods In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t -statistical parametric mapping [SPM{ t }]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. Results Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18,…
A ventral striatal prediction error signal in human fear extinction learning.
2021
Animal studies have shown that the prediction error (PE) signal that drives fear extinction learning is encoded by phasic activity of midbrain dopamine (DA) neurons. Thus, the extinction PE resembles the appetitive PE that drives reward learning. In humans, fear extinction learning is less well understood. Using computational neuroimaging, a previous study from our group reported hemodynamic activity in the left ventral putamen, a subregion of the ventral striatum (VS), to correlate with a PE function derived from a formal associative learning model. The activity was modulated by genetic variation in a DA-related gene. To conceptually replicate and extend this finding, we here asked whether…
Amelanotic conjunctival melanoma
2006
Conjunctival melanoma is a rare condition of the eye pigment predominantly affecting white adults. We describe a 32-year-old white man with an amelanotic malignant melanoma of the conjunctiva that is not associated with primary acquired melanosis (PAM) or melanocytic nevus. The patient presented with a 2-year history of nonpigmented vascularized nodules of the right eye. Results of hematoxylin and eosin (H and E) staining of the lesion showed an invasive nodule with vertical spreading, invasion of the substantia propria corneae, and ulceration. S100 protein was expressed in the cells of the invasive nodule. HMB45 protein was highly positive in the melanoma cells. The de novo amelanotic mali…
High Iodine Concentration Contrast Material for Noninvasive Multislice Computed Tomography Coronary Angiography
2006
OBJECTIVE: The objective of this study was to compare intracoronary attenuation on 16-row multislice computed tomography (16-MSCT) coronary angiography using 2 contrast materials (CM) with high iodine concentration. MATERIAL AND METHODS: Forty consecutive patients (29 male, 11 female; mean age, 61 ± 11 years) with suspected coronary artery disease were randomized to 2 groups to receive 100 mL of either iopromide 370 (group 1: Ultravist 370, 370 mg iodine/mL; Schering AG, Berlin, Germany) or iomeprol 400 (group 2: Iomeron 400, 400 mg iodine/mL; Bracco Imaging SpA, Milan, Italy). Both CM were administered at a rate of 4 mL/s. All patients underwent 16-MSCT coronary angiography (Sensation 16; …
A Nonlinear Approach to Brain Function: Deterministic Chaos and Sleep EEG
1992
In order to perform a nonlinear dimensional analysis of the sleep electroencephalogram (EEG), we applied an algorithm proposed by Grassberger and Procaccia to calculate the correlation dimension D2 of different sleep stages under Lorazepam medication versus placebo. This correlation dimension characterizes the dynamics of the sleep EEG and it estimates the degrees of freedom of the signal under study. We demonstrate that slow-wave sleep depicts a much smaller dimensionality than light or rapid eye movement (REM) sleep, and that Lorazepam does not alter the EEG's dimensionality except in stage II and REM.
Strange Attractors, Chaotic Behavior and Informational Aspects of Sleep EEG Data
1992
In order to perform a nonlinear dimensional analysis of the sleep EEG, we applied an algorithm proposed to calculate the correlation dimension D2 of different sleep stages. D2 characterizes the dynamics of the sleep EEG, estimates the degrees of freedom, and describes the complexity of the signal under study. An attempt is made to correlate dimensionality analysis and informational aspects of the sleep EEG. Information processing by the brain during different sleep stages of healthy subjects under the influence of lorazepam and in unmedicated acute schizophrenics is estimated.