Biomedical subjects

D F Braus

Publications and source records attributed to D F Braus.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Diffusion tensor imaging (DTI) and functional magnetic resonance tomography (fMRI) expand methodological spectrum in psychiatric research].

In psychiatric research, there is a growing interest in the microstructural and functional characteristics of brain networks, which often form the basis of current etiological concepts. As a result of novel magnetic resonance imaging techniques, the pathogenic characteristics of neuronal activity and connectivity can be examined in a noninvasive, safe, and repeatable manner. Functional magnetic resonance imaging (fMRI) uses blood oxygenation level-dependent (BOLD) measures for identifying the gray matter contribution to cognition. Diffusion tensor imaging (DTI) reveals the course and structural integrity of white matter projections. Because DTI does not require special motivation and performance, group differences in psychiatry are more easily interpreted in terms of underlying pathology. To date few studies have tried to investigate both, i.e. dynamic and microstructural data in the sense of a modern multi-dimensional investigation approach. The combination of both techniques, however, seems to offer a promising vehicle to further extent our current understanding of mental disorders and to identify populations at risk. In addition to addressing findings in psychiatric research, the present article presents a technical overview of DTI and examines the limitations and potential applications of both techniques.

Anisotropy↗

PubMed2001

Hippocampal 1H-MRSI in ecstasy users.

In recent years the illicit drug ecstasy (MDMA, 3,4-methylenedioxymethamphetamine) has come into widespread use among young people. Despite clear evidence for the neurotoxic potential of MDMA in animals, corresponding evidence in humans is limited to indirect findings. In an exploratory study we compared the hippocampal 1H-MRSI (magnetic resonance spectroscopic imaging) spectra of five MDMA users with those of controls with no history of substance abuse. Although 1H

Adult↗

PubMed2001

Effects of antipsychotic treatment on membrane phospholipid metabolism in schizophrenia.

Several studies have shown an increased membrane phospholipid turnover in brain and blood cells of schizophrenic patients. However the specificity of these findings for schizophrenia and the effects of longterm antipsychotic treatment had yet to be demonstrated. In the present study we measured the concentrations of phospholipids in platelet membranes from 67 neuroleptic-free schizophrenic patients compared to both healthy and psychiatric controls, followed by repeated measurements during a 6 months antipsychotic treatment period. At baseline, levels of the main phospholipid components phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were decreased and lysophosphatidylcholine (LPC), a major breakdown product of phospholipid metabolism, was increased in schizophrenic patients compared to healthy and to psychiatric controls, suggesting a specificity of the findings for schizophrenia. During the first 3-weeks on antipsychotic drug treatment LPC levels decreased to control values, but increased again during the following 6 months, reaching significantly higher levels than controls at the end of this period. Thus, at least in peripheral cells an increased breakdown of phospholipids in schizophrenia appears to be present during the acute episode, being influenced only by initial antipsychotic treatment, but without evidence of a long lasting treatment effect on membrane metabolism.

Adult↗

PubMed2001

Alcohol-associated stimuli activate the ventral striatum in abstinent alcoholics.

Alcohol-associated cues may act as conditioned stimuli that activate the brain reward system and motivate alcohol intake in alcoholics. Alcohol-associated visual stimuli were presented during functional magnetic resonance imaging. An activation of the ventral putamen was observed in alcoholics but not in control subjects. Patients with a strong activation of the ventral putamen relapsed during the next three months. This observation supports the hypothesis that alcohol use affects areas involved in brain reward circuits and that their stimulus-induced activation may be associated with an increased risk for relapse.

Adult↗

PubMed2001

[Current overview of structural magnetic resonance imaging in schizophrenia].

Non-invasive morphologic imaging (computer tomography, magnetic resonance imaging, MRT) has contributed significantly to our understanding of schizophrenic disorders as diseases of the brain. Improved MRT techniques enable us to analyse anatomical substructures. The present overview evaluates peer-reviewed MRT studies published between 1994 and July 2000 and provides a comparison with our own results. Chronic schizophrenic patients most frequently show an enlargement in the ventricular system along with a reduction in grey matter. A more detailed subdivision into cortical and subcortical regions additionally shows the noted volume reduction to be limited to specific areas within the brain rather than being distributed equally throughout the brain. Within the area of the temporal lobes the two most frequently affected areas are the hippocampus and the gyrus temporalis superior. Alterations within these areas correlate with clinical symptoms such as hallucinations or thought disorders. Within the frontal cortex nearly 70% of all studies show a decrease in overall volume, while 63% note a reduction in size within the thalamus and 60% in the cerebellum. Morphologically speaking these structures therefore play the greatest role in the pathophysiology of schizophrenia and the onset of clinical symptoms. More recent studies also showed a specific progression in subgroups of patients pointing toward a neurodegenerative process. Additionally there are a number of differential antipsychotic effects following longterm treatment with typical neuroleptics as compared to atypical antipsychotics. Based on these findings future longitudinal studies should examine to what extent such a progressive decrease in volume might be influenced by treatment with modern antipsychotics.

Humans↗

PubMed2001

Favorable effect on neuronal viability in the anterior cingulate gyrus due to long-term treatment with atypical antipsychotics: an MRSI study.

In the present study, we evaluated 23 chronic schizophrenic patients under stable clinical conditions to determine the association between neuronal viability, as measured by in vivo(1)H magnetic resonance spectroscopic imaging (MRSI), and antipsychotic drug effects in the anterior cingulate cortex. Careful screening of the medication history showed that 11 of these patients had been treated with traditional neuroleptics only, while the others had switched to atypical antipsychotics due to non-response to traditional drugs. The group of patients receiving typical neuroleptic medication showed a mean NAA that was lower than in the group of patients receiving atypical antipsychotic drugs. Removing the duration of illness effect indicated a significant correlation between the NAA signal in the anterior cingulate gyrus and time on atypical drugs in patients under long-term atypical antipsychotic treatment. In contrast, patients with traditional medication revealed progressive decrease in the NAA level. These results suggest a favorable effect on neuronal viability in the anterior cingulate gyrus due to long-term treatment with atypical antipsychotics.

Adult↗

PubMed2001

[Antipsychotics and phospholipid metabolism in schizophrenia].

To date numerous in-vivo (31)P-MRS and in-vitro studies in schizophrenic patients have been able to demonstrate changes in their membrane phospholipid metabolism, which might be relevant for the cause and the therapeutic responsiveness of this disorder. Thus far, however, only limited studies exist regarding the specificity of these findings for schizophrenia and the effect of antipsychotic medication. The present study examined the composition of membrane phospholipids in platelets of 67 neuroleptic-free schizophrenic patients compared to healthy and psychiatric controls. In a subsample of the schizophrenic patients we determined the effect of antipsychotic treatment on the phospholipid metabolism during six-months follow up. While untreated patients showed a decrease in major membrane phospholipid components, i.e. phosphatidylcholine and phosphatidylethanolamine, when compared to control subjects, as well as an increase in their breakdown-product lysophosphatidylcholine (LPC), there was a significant reduction in LPC during three weeks of pharmacotherapy with haloperidol. After six months treatment with different antipsychotics some divergent effects on phospholipid metabolism in schizophrenic patients could be demonstrated. While in the long-term course LPC remained decreased under continuous therapy with typical neuroleptics, patients being treated with the atypical drug zotepine showed an increase in LPC compared to their baseline level before therapy. Thus, specific mechanisms of the different antipsychotic therapies on phospholipid metabolism might serve to explain the divergent findings of (31)P-MRS in medicated patients.

Adult↗

PubMed2001

[Homosexual pedophilia and functional networks - An fMRI case report and literature review].

Pedophilia is a complex bio-psycho-social disorder often associated with serious offending. Knowledge about neurobiological correlates that could serve as diagnostic and maybe even as prognostic markers is limited. FMRI examination, which shows neuronal activation in vivo and therefore represents a neurobiological correlate, was not done in pedophilia so far. We report on results of an fMRI examination in a homosexual pedophilic sex offender who differed significantly in neuronal activation during exposure to arousing visual material (young boys in underwear) from normal controls. In self assessment on a visual analogous scale the pedophilic offender scored the pictures of the boys as not being interesting and sexually not stimulating. Nevertheless presentation of the pictures of the boys resulted in the pedophilic offender in a significant activation of the attention network and the right orbitofrontal cortex. In contrast to the controls there was no activation of left hemispheric areas relevant for speech. The study design will be continued in a larger sample to examine whether there is a possible neurobiological correlate of pedophilia which can be changed by therapeutic interventions.

Adult↗

PubMed2001

Lower concentration of thalamic n-acetylaspartate in patients with schizophrenia: a replication study.

OBJECTIVE: Using proton magnetic resonance spectroscopic imaging, the authors measured thalamic N-acetylaspartate (NAA) concentrations in patients with schizophrenia. METHOD: The study included 15 schizophrenic patients on a stable medication regimen and 15 age-matched healthy comparison subjects. Concentrations of NAA, creatine plus phosphocreatine, and choline-containing compounds in bilateral thalamic regions were determined. RESULTS: Previous findings of lower NAA concentration in the left and right mediodorsal region of the thalamus and significant correlations between left and right thalamic NAA measures in patients with schizophrenia were corroborated. Furthermore, the concentrations of choline-containing compounds were significantly lower in the schizophrenic patients. No group differences in creatine plus phosphocreatine were found. CONCLUSIONS: There is strong evidence for neuronal dysfunction or loss in the mediodorsal region of the thalamus in patients with schizophrenia.

Adult↗

PubMed2000

[Effective treatment of depressive disorder with psychotic symptoms by olanzapine combination therapy].

HISTORY AND ADMISSION FINDINGS: Four days after swallowing lithium and amitriptyline tablets with suicidal intent, a 48-year-old man was admitted. He was known to be suffering from recurrent depression which had led to 7 previous hospital admissions. At psychiatric assessment he appeared to be depressed with reduced ability of affective changes and impaired formal reasoning. He exhibited delusions of guilt and reference. His sleep was impaired and appetite diminished. INVESTIGATIONS: Serum lithium level was 1.98 mmol/l (therapeutic range 0.8-1.0 mmol/l). An ECG demonstrated sinus tachycardia, the EEG showed theta waves with mild general changes. DIAGNOSIS, TREATMENT AND COURSE: He was diagnosed as suffering from severe depressive syndrome with psychotic symptoms. He was given both antidepressive and neuroleptic drugs: mirtazapine 30 mg daily (p.d.) and halperidol 10 mg p.d.. When both the depressive and psychotic symptoms were treatment-resistant, even after a change from mirtazapine to venlafaxine (300 mg p.d.), the drug regimen was changed to sertraline, 150 mg p.d., and olanzapine, 20 mg p.d.. While this brought about improvement, his condition deteriorated when olanzapine was withdrawn. But all symptoms completely disappeared when olanzapine was again given. Spontaneous remission in the future thus seems unlikely to occur. CONCLUSION: This case illustrates that the atypical antipsychotic drug olanzapine has some advantages over such typical antipsychotic drug olanzapine has some advantages over such typical antipsychotic medication as butyrophenone. The underlying mechanism for this greater efficacy is probably the difference in receptor-binding capacity between these drugs, the former inhibiting some serotonin receptors so that it is synergistic with antidepressives that inhibit serotonin transport.

Antidepressive Agents, Second-Generation↗

PubMed2000

Cortical response to motor stimulation in neuroleptic-naive first episode schizophrenics.

The purpose of the present study was to evaluate the cortical response to motor stimulation in neuroleptic-naive first episode schizophrenics in comparison to matched controls using a high speed functional magnetic resonance imaging technique (fMRI). Twelve patients satisfying ICD 10 criteria (F20.0) for schizophrenia (paranoid subtype) as well as sex- and age-matched healthy volunteers participated in this study. All subjects underwent fMRI examination on a conventional 1.5 T MR unit equipped with an echo-planar imaging booster. The blood oxygen level dependent (BOLD) response of the sensorimotor cortex and the higher order SMA region was evaluated during performance of a left hand sequential finger opposition task. Special care was taken to minimize performance and motion artifacts. Patients and controls showed no notable difference with respect to laterality, changes of signal intensity or spatial extent of activation within the primary and higher order motor regions. Using high speed fMRI no fundamental motor cortical dysfunction was evident in a group of paranoid neuroleptic-naive first episode schizophrenic patients. In contrast to data previously reported for chronic disorganized medicated patients, these results suggest that motor dysfunction is not part of the phenomenology of acute paranoid first episode patients.

Acute Disease↗

PubMed2000

Effects of age, medication, and illness duration on the N-acetyl aspartate signal of the anterior cingulate region in schizophrenia.

The authors performed a MRSI study of the anterior cingulate gyrus in 19 schizophrenic patients under stable medication and 16 controls in order to corroborate previous findings of reduced NAA in the anterior cingulate region in schizophrenia. Furthermore, correlations between NAA in the anterior cingulate gyrus and age or illness duration have been determined. A decreased NAA signal was found in the anterior cingulate gyrus of patients compared to controls. Subdividing the patient group into two groups depending on medication revealed that the group of patients receiving a typical neuroleptic medication showed a lower mean NAA in comparison to the group of patients receiving atypical antipsychotic drugs. No significant group differences in the creatine and phosphocreatine signal or the signal from choline-containing compounds were found. The NAA signal significantly correlated with age, and therefore, individual NAA values were corrected for the age effect found in the control group. The age-corrected NAA signal in schizophrenia correlated significantly with the duration of illness. The detected correlations of NAA decrease with age and illness duration are consistent with recent imaging studies where progressing cortical atrophy in schizophrenia was found. Further studies will be needed to corroborate a possible favorable effect of atypical antipsychotics on the NAA signal.

Adult↗

PubMed2000

The hippocampus in patients treated with electroconvulsive therapy: a proton magnetic resonance spectroscopic imaging study.

BACKGROUND: We monitored the effect of electroconvulsive therapy (ECT) on the nuclear magnetic resonance-detectable metabolites N-acetylaspartate, creatine and phosphocreatine, and choline-containing compounds in the hippocampus by means of hydrogen 1 magnetic resonance spectroscopic imaging. We hypothesized that if ECT-induced memory deterioration was associated with neuronal loss in the hippocampus, the N-acetylaspartate signal would decrease after ECT and any increased membrane turnover would result in an increase in the signal from choline-containing compounds. METHODS: Seventeen patients received complete courses of ECT, during which repeated proton magnetic resonance spectroscopic imaging studies of the hippocampal region were performed. Individual changes during the course of ECT were compared with values obtained in 24 healthy control subjects and 6 patients remitted from major depression without ECT. RESULTS: No changes in the hippocampal N-acetylaspartate signals were detected after ECT. A significant mean increase of 16% of the signal from choline-containing compounds after 5 or more ECT treatments was observed. Despite the mostly unilateral ECT application (14 of 17 patients), the increase in the choline-containing compound signal was observed bilaterally. Lactate or elevated lipid signals were not detected. All patients showed clinical amelioration of depression after ECT. CONCLUSIONS: Electroconvulsive therapy is not likely to induce hippocampal atrophy or cell death, which would be reflected by a decrease in the N-acetylaspartate signal. Compared with an age-matched control group, the choline-containing compounds signal in patients with a major depressive episode was significantly lower than normal, before ECT and normalized during ECT.

Adult↗

PubMed2000

[Acute tongue and pharyngeal spasms during changeover from clozapine to amisulpride. A case example].

With the advent of atypical antipsychotics, quality of life for patients with schizophrenia has improved significantly. The positive effects are based not only on the compliance-enhancing reduction of extrapyramidal side effects but also due to improved cognitive function and social integration, shorter duration, and overall reduction of hospital treatment. Numerous controlled studies have addressed the issue of switching patients from typical to atypical antipsychotics. However, published data on substituting one atypical antipsychotic for another are preliminary and very limited. This case report describes acute side effects which occurred when switching from clozapine to amisulpride and discusses mechanisms on the receptor level. Regarding these two agents, the clinical relevance of the knowledge of receptor profiles is outlined.

Acute Disease↗

PubMed1999

Antipsychotic drug effects on motor activation measured by functional magnetic resonance imaging in schizophrenic patients.

Brain function and laterality in schizophrenia were investigated by means of a simple motor task with a self-generated left-hand sequential finger opposition (SFO) using a whole-brain high-speed (100 ms per slice) functional imaging technique. Neuroleptic-naïve, acutely ill schizophrenic patients were compared to schizophrenic patients under stable neuroleptic medication and matched controls. The goal was to evaluate both the motor function in first-episode patients and possible effects of different neuroleptic treatments on functional MRI results. Forty patients satisfying ICD 10 criteria (F20.x) for schizophrenia and sex- and age-matched healthy volunteers participated in this study. All subjects underwent fMRI examinations on a conventional 1.5 T MR unit. The primary sensorimotor cortex and the high-order supplementary motor area (SMA) were evaluated. There was a close similarity in the activation of the primary and high-order (SMA) sensorimotor areas between first-episode schizophrenic patients and controls. In contrast, a significant reduction in the overall blood oxygen level dependent (BOLD) response was seen in sensorimotor cortices (contra- and ipsilateral) in schizophrenic patients under stable medication with typical neuroleptics. This effect was not present in patients treated with atypical antipsychotics. Both antipsychotic treatments, however, led to a significant reduction in activation of the SMA region compared to controls and neuroleptic-naïve subjects. Thus, the present study provides no evidence for the localized involvement of the primary motor cortex or the SMA as a relatively stable vulnerability marker in schizophrenia. There is, however, strong evidence that neuroleptics themselves influence fMRI activation patterns and that there are major differences between typical neuroleptics and atypical antipsychotics.

Adult↗

PubMed1999

Structural neuroimaging in schizophrenia. An integrative view of neuromorphology.

The use of structural magnetic resonance imaging (MRI) in studies of schizophrenia has resulted in a more detailed picture of anatomic areas which may be altered in this syndrome. Thus far, there have been over 130 studies of schizophrenia using MRI and, taken together, they present a clear picture of a group of disorders with altered brain structure. Their major finding is a confirmation of the older pneumoencephalography and computertomography studies showing an enlargement of lateral ventricles and a volume reduction seen in the temporal lobe. When structural studies are carried out in other cortical and subcortical regions, however, the volume reduction is not so uniform, but rather restricted to certain areas in a given patient. In addition medication effects can be seen especially in the caudate nucleus which tend to increase in volume after long-term neuroleptic drug usage and again normalize under the atypical drug clozapine. These data are consistent with a neurodevelopmental model of schizophrenia and with some kind of progressive neurodegenerative process. This review suggests that an integrative model with initial developmental errors may underlie the majority of cases of schizophrenia, but that cases of chronic schizophrenia appear to involve progressive neurodegeneration. In assessing the scatter in available data, it appears that there is no consistent neuropathology across all cases of schizophrenia and preferential areas of dysfunction can be determined. Thus, there seems a collection of subtle neurodevelopmental errors which can lead to various forms of schizophrenia and that at least some types of schizophrenia most probably also involve a neurodegenerative process which could in fact be a consequence of the initial developmental defect.

Brain↗

PubMed1999

Reduced activation and altered laterality in two neuroleptic-naive catatonic patients during a motor task in functional MRI.

BACKGROUND: Catatonia, a symptom complex with motor, affective and cognitive symptoms seen in a variety of psychotic conditions and with organic disease, was examined using a motor task using functional magnetic resonance imaging (fMRI). METHODS: Two acute catatonic patients and two age- and sex-matched healthy controls performed sequential finger opposition (SFO) after being medicated with 2 mg of lorazepam (i.v.). Functional magnetic resonance images were collected using a gradient echo pulse sequence (EPI). RESULTS: Patients with catatonia showed reduced motor activation of the contralateral motor cortex during SFO of the right hand, ipsilateral activation was similar for patients and controls. There were no differences in the activation of the SMA. During left hand activation the right-handed catatonic patients showed more activation in the ipsilateral cortex, a reversal from the normal pattern of activation in which the contralateral side shows four to five times more activation than the ipsilateral side. CONCLUSIONS: In catatonic patients there is a decreased activation in motor cortex during a motor task compared to matched medicated healthy controls. In addition activation of the non-dominant side, left-handed activity in right-handed patients, results in a total reversal of the normal pattern of lateral activation suggesting a disturbance in hemispheric localization of activity during a catatonic state.

Acute Disease↗

PubMed1997

Real-time direct volume rendering in functional magnetic resonance imaging.

Direct volume rendering is a visualization method that allows display of all information hidden in three-dimensional data sets of, for example, computed tomography or magnetic resonance imaging (MRI). In contrast to commonly used surface rendering methods, these algorithms need no preprocessing but suffer from a high computational complexity. A real-time rendering system, VIRIM (Vitec: Visualization Technology GmbH, Mannheim, Germany), cuts down rendering times of minutes on normal workstations to an interactive rate of 1 second or less. The immediate visual feedback allows interactive steering of the visualization process to achieve insight into the internal three-dimensional structure of objects. Additional information is obtained by using an interactive gray-value segmentation tool that both allows segmentation of the data set according to bone, tissue, and liquor and display of multifunctional data sets (e.g., functional MRI [fMRI] data sets). Thus, real-time direct volume rendering allows segmentation and volume data processing of functional and anatomical MR data sets simultaneously. As this method can be integrated in the clinical routine, it is of great importance for real-time motion artifact detection and the interpretation of fMRI data acquired during cognitive experiments with normal subjects and psychiatric patients. Because of the free programmability of VIRIM, more complex matching procedures are currently being investigated for future implementation.

Brain↗