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Christian Brenneis

Publications and source records attributed to Christian Brenneis.

At least 19 recordsLinked to original sources
PubMed2007

Abnormal responses to repetitive transcranial magnetic stimulation in multiple system atrophy.

We studied the response of the motor cortex to brief trains of suprathreshold repetitive transcranial magnetic stimulations (rTMS) in patients with the Parkinson-variant of multiple system atrophy (MSA-P) and compared it to patients with idiopathic Parkinson's disease (PD) and healthy controls. Eight subjects were studied in each group, and patients were matched for disease severity as assessed by Hoehn & Yahr stages. rTMS was delivered at rest and during low-level contractions in trains of 10 stimulations at 5 Hz, and stimulation intensity was set to result in an motor evoked potential (MEP) in the first dorsal interosseus muscle of 0.5 to 1.0 mV. In MSA-P, MEP amplitude at rest was already reduced after the second stimulus and remained so, while it did not change in PD and controls. During contraction, MEP size did not change during the train in any group. The silent period that followed the last stimulus was of similar duration as the first stimulus in MSA-P, but was increased in PD and controls. These findings indicate that abnormal inhibition occurs within the motor cortex in MSA-P, despite dopaminergic treatment and indicate differences in cortical dysfunction between MSA-P and PD. We suggest that these abnormalities reflect the motor cortex pathology found in MSA-P.

Electromyography↗
PubMed2006

Scanning electron microscopy of the neuropathology of murine cerebral malaria.

BACKGROUND: The mechanisms leading to death and functional impairments due to cerebral malaria (CM) are yet not fully understood. Most of the knowledge about the pathomechanisms of CM originates from studies in animal models. Though extensive histopathological studies of the murine brain during CM are existing, alterations have not been visualized by scanning electron microscopy (SEM) so far. The present study investigates the neuropathological features of murine CM by applying SEM. METHODS: C57BL/6J mice were infected with Plasmodium berghei ANKA blood stages. When typical symptoms of CM developed perfused brains were processed for SEM or light microscopy, respectively. RESULTS: Ultrastructural hallmarks were disruption of vessel walls, parenchymal haemorrhage, leukocyte sequestration to the endothelium, and diapedesis of macrophages and lymphocytes into the Virchow-Robin space. Villous appearance of observed lymphocytes were indicative of activated state. Cerebral oedema was evidenced by enlargement of perivascular spaces. CONCLUSION: The results of the present study corroborate the current understanding of CM pathophysiology, further support the prominent role of the local immune system in the neuropathology of CM and might expose new perspectives for further interventional studies.

Animals↗
PubMed2006

A widespread distinct pattern of cerebral atrophy in patients with alcohol addiction revealed by voxel-based morphometry.

BACKGROUND: Patients with alcohol addiction show a number of transient or persistent neurological and psychiatric deficits. The complexity of these brain alterations suggests that several brain areas are involved, although the definition of the brain alteration patterns is not yet accomplished. AIM: To determine brain atrophy patterns in patients with alcohol dependence. METHODS: Voxel-based morphometry (VBM) of grey matter (GM) and white matter (WM) was performed in 22 patients with alcohol dependence and in 22 healthy controls matched for age and sex. RESULTS: In patients with alcohol dependence, VBM of GM revealed a significant decrease in density (p<0.001) in the precentral gyrus, middle frontal gyrus, insular cortex, dorsal hippocampus, anterior thalamus and cerebellum compared with controls. Reduced density of WM was found in the periventricular area, pons and cerebellar pedunculi in patients with alcohol addiction. CONCLUSIONS: Our findings provide evidence that alcohol addiction is associated with altered density of GM and WM of specific brain regions. This supports the assumption that alcohol dependence is associated with both local GM dysfunction and altered brain connectivity. Also, VBM is an effective tool for in vivo investigation of cerebral atrophy in patients with alcohol addiction.

Adult↗
PubMed2006

Pharmacokinetics of intravenous linezolid in cerebrospinal fluid and plasma in neurointensive care patients with staphylococcal ventriculitis associated with external ventricular drains.

The pharmacokinetic profile of linezolid in cerebrospinal fluid (CSF) in five neurointensive care patients with staphylococcal ventriculitis was studied. The mean area under concentration-time curve (+/- standard deviation) was 63 +/- 18.9 mg x h/liter, with a CSF-to-plasma ratio of 0.8 +/- 0.3. Times above MIC in CSF were 99.8% and 57.2% for pathogens with MICs of 2 mg/liter and 4 mg/liter, respectively.

Acetamides↗
PubMed2006

Low dose treatment with the synthetic cannabinoid Nabilone significantly reduces spasticity-related pain : a double-blind placebo-controlled cross-over trial.

About 30% of patients with chronic upper motor neuron syndrome (UMNS) suffer from disabling spasticity-related pain not sufficiently correctable by conventional treatment. Delta9-tetrahydrocannabinol (Delta(9)-THC) was reported to add benefit in the treatment of pain in patients with multiple sclerosis (MS). The question arose whether synthetic cannabinoids with lower potential for psychotropic side effects could be effective as well. To evaluate the safety and efficacy of low dose treatment with the synthetic cannabinoid Nabilone (1 mg per day) on spasticity-related pain a placebo-controlled double-blind crossover trial was performed.11 out of 13 included patients completed the study. The 11-Point-Box-Test showed a significant decrease of pain under Nabilone (p < 0.05), while spasticity, motor function and activities of daily living did not change. 5 patients reported side effects: one moderate transient weakness of the lower limbs (Nabilone phase, drop out), three mild drowsiness (two Nabilone, one placebo) and one mild dysphagia (placebo). One patient was excluded from the study due to an acute relapse of multiple sclerosis (Nabilone phase, drop out). Nabilone 1 mg per day proved to be a safe and easily applicable option in the care of patients with chronic UMNS and spasticity-related pain otherwise not controllable.

Activities of Daily Living↗
PubMed2006

Topography of dopamine transporter availability in progressive supranuclear palsy: a voxelwise [123I]beta-CIT SPECT analysis.

BACKGROUND: Dopaminergic loss can be visualized by means of iodine I 123-labeled 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane ([(123)I]beta-CIT) single-photon emission computed tomography (SPECT) in several neurodegenerative parkinsonian disorders. Most previous SPECT studies have adopted region-of-interest methods for analysis, which are subjective and operator dependent. OBJECTIVE: To objectively localize the cerebral dopamine transporter status in the early stages of progressive supranuclear palsy (PSP). DESIGN: Prospective study. SETTING: Parkinson disease outpatient clinic. PATIENTS: Fourteen patients with PSP, 17 with Parkinson disease (PD), 15 with Parkinson-variant multiple-system atrophy (MSA-P), and 13 healthy control subjects, matched for age and disease duration. INTERVENTIONS: Statistical parametric mapping applied to [(123)I]beta-CIT SPECT. MAIN OUTCOME MEASURES: Differences in [(123)I]beta-CIT uptake. RESULTS: All patients with the different parkinsonian disorders showed a significant decrease in striatal [(123)I]beta-CIT uptake without any overlap with the control group. In patients with MSA-P and PSP, an additional reduction in brainstem [(123)I]beta-CIT signal compared with controls and patients with PD was identified with statistical parametric mapping. Midbrain [(123)I]beta-CIT uptake discriminated atypical parkinsonian disorders from PD with an overall correct classification of 91.3%. On the other hand, [(123)I]beta-CIT SPECT failed to discriminate PSP and MSA-P. CONCLUSION: By applying statistical parametric mapping to [(123)I]beta-CIT SPECT images of patients with PSP, a widespread decline of monoaminergic transporter availability including the striatum and brainstem was localized in PSP, discriminating patients with PSP from patients with PD, but not from those with MSA-P. Quantification of midbrain dopamine transporter signal may therefore enhance the utility of SPECT imaging in the differential diagnosis of patients with parkinsonism.

Aged↗
PubMed2006

Cortical atrophy in the cerebellar variant of multiple system atrophy: a voxel-based morphometry study.

This study aimed to determine in vivo the atrophy patterns in clinically established cerebellar variant of multiple-system atrophy (MSA-C) using voxel-based morphometry (VBM). Thirteen patients with MSA-C (12 probable, 1 possible) and 13 healthy controls matched for age and sex were included. High-resolution MR images were acquired with a 1.5 T scanner. Images were normalized onto a study-specific template, segmented into the tissue compartments, modulated with the Jacobian determinants, and finally smoothed with a Gaussian kernel filter of 10 mm. The general linear model was used to assess statistical differences in gray and white matter. Infratentorial atrophy was observed in the cerebellar hemispheres, vermis, mesencephalon, and pons of MSA-C patients. Supratentorial volume loss was found in orbitofrontal and mid-frontal regions as well as in temporomesial and insular areas of both hemispheres. A negative correlation was observed between a cerebellar ataxia score and the volume of cerebellar hemispheres, peduncles, and pons. To compare this atrophy pattern to that of spinocerebellar ataxia (SCA2), which was previously reported by our group, a conjunction analysis was assessed. We observed a volume loss shared by both disorders comprising the cerebellum, vermis, pons, mesencephalon, orbitofrontal, mid-frontal, and temporomesial cortex of both hemispheres as well as the left insular cortex.

Adult↗
PubMed2006

Diffusion-weighted imaging in Huntington's disease.

Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder that results from an expanded trinucleotide (CAG) repeat on the huntingtin gene. Neurodegeneration in HD affects most prominently the basal ganglia. Therefore, diffusivity was obtained in the basal ganglia and thalamus of 29 patients with early HD and 27 healthy volunteers by means of the trace of the diffusion tensor (Trace(D)). Putaminal, caudate, pallidal, and thalamic Trace(D) values were increased in patients with HD compared with controls. Increased diffusivity in the putamen and caudate nucleus correlated with global functional impairment, CAG repeat length, as well as bicaudate ratio. Diffusion-weighted imaging appears to be a promising surrogate marker for disease severity in HD. Sensitivity to change remains to be established longitudinally.

Activities of Daily Living↗
PubMed2006

Inhibition of prostaglandin E2 synthesis by SC-560 is independent of cyclooxygenase 1 inhibition.

Prostaglandin E2 (PGE2) produced by cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1) plays an important role in the pathophysiology of inflammation, pain, and fever. We investigated the actions of TNFalpha toward stimulation of PGE2 synthesis in primary spinal cord neurons. TNFalpha induced COX-2 and mPGES-1 expression in neurons, followed by formation of PGE2, which was blocked by a selective COX-2 inhibitor. Surprisingly, the "selective COX-1" inhibitor SC-560 completely inhibited TNFalpha-induced PGE2 synthesis in neurons at nanomolar concentrations. Moreover, SC-560 inhibited PGE2 and thromboxane A2 synthesis in human monocytes and platelets with IC50 of 1.8 nM and 2.5 nM, respectively. SC-560 treatment neither altered TNFalpha-induced COX-2 or mPGES-1 expression nor did the addition of the calcium ionophore A23187 or arachidonic acid reverse the inhibition by SC-560. Moreover, no influence of SC-560 on PGE2 synthase activities or PGE2 transport was seen. Most importantly, SC-560 blocked TNFalpha-induced PGE2 synthesis in COX-1-deficient spinal cord neurons, demonstrating a COX-1-independent inhibition of PGE2 synthesis. Although SC-560 inhibited LPS-induced PGE2 synthesis in neurons and RAW264.7 macrophages in whole cell assays, no inhibition was observed in lysates of the same cells. Taken together our data demonstrate that SC-560 acts at least in some cell types as an unselective COX inhibitor despite its selectivity toward COX-1 under cell-free conditions.

Animals↗
PubMed2006

Language lateralization in temporal lobe epilepsy: a comparison between fMRI and the Wada Test.

PURPOSE: Recent studies have claimed that language functional magnetic resonance imaging (fMRI) can identify language lateralization in patients with temporal lobe epilepsy (TLE) and that fMRI-based findings are highly concordant with the conventional assessment procedure of speech dominance, the intracarotid amobarbital test (IAT). METHODS: To establish the power of language fMRI to detect language lateralization during presurgical assessment, we compared the findings of a semantic decision paradigm with the results of a standard IAT in 68 patients with chronic intractable right and left temporal lobe epilepsy (rTLE, n=28; lTLE, n=40) who consecutively underwent a presurgical evaluation program. The patient group also included 14 (20.6%) subjects with atypical (bilateral or right hemisphere) speech. Four raters used a visual analysis procedure to determine the laterality of speech-related activation individually for each patient. RESULTS: Overall congruence between fMRI-based laterality and the laterality quotient of the IAT was 89.3% in rTLE and 72.5% in lTLE patients. Concordance was best in rTLE patients with left speech. In lTLE patients, language fMRI identified atypical, right hemisphere speech dominance in every case, but missed left hemisphere speech dominance in 17.2%. Frontal activations had higher concordance with the IAT than did activations in temporoparietal or combined regions of interest (ROIs). Because of methodologic problems, recognition of bilateral speech was difficult. CONCLUSIONS: These data provide evidence that language fMRI as used in the present study has limited correlation with the IAT, especially in patients with lTLE and with mixed speech dominance. Further refinements regarding the paradigms and analysis procedures will be needed to improve the contribution of language fMRI for presurgical assessment.

Adolescent↗
PubMed2005

Voxel-wise analysis of diffusion weighted imaging reveals disruption of the olfactory tract in Parkinson's disease.

Diffusion weighted imaging (DWI) and the trace of diffusion tensor [Trace (D)], a marker of water molecule diffusivity, provide information on structural integrity of nervous tissues. To investigate structural lesions within the brain's neuronal architecture in early stages of Parkinson's disease, 12 patients with disease duration of 3.5 +/- 1.5 years were studied with DWI. Data were compared with 12 age-matched healthy control subjects. To objectively localize focal changes of structural neuronal integrity without having to make an a priori hypothesis as to its location statistical parametric mapping (SPM) was applied to our DWI study. SPM localized significant increases of diffusivity in the region of both olfactory tracts in patients (P < 0.001). Trace (D) cut-off values for the voxel cluster of the olfactory tracts have been calculated from the subjects entered into SPM and applied to a total of 17 different individuals (9 patients with Parkinson's disease, disease duration 3.1 +/- 1.3 years and 8 age-matched healthy subjects). Out of 17 subjects, 16 subjects, i.e. 94%, were correctly discriminated with a sensitivity of 100% and a specificity of 88%. All patients with Parkinson's disease were correctly classified and only one normal subject was classified as having the disease, underlining the high potential of this method to separate patients with the illness from healthy subjects. Increased diffusivity in the olfactory tract is in line with the well-established clinical finding of hyposmia in Parkinson's disease. Whether DWI can be used as a marker to identify individuals at risk to develop this disease remains to be shown.

Case-Control Studies↗
PubMed2005

Case report: severe heat stroke with multiple organ dysfunction - a novel intravascular treatment approach.

INTRODUCTION: We report the case of a patient who developed a severe post-exertional heat stroke with consecutive multiple organ dysfunction resistant to conventional antipyretic treatment, necessitating the use of a novel endovascular device to combat hyperthermia and maintain normothermia. METHODS: A 38-year-old male suffering from severe heat stroke with predominant signs and symptoms of encephalopathy requiring acute admission to an intensive care unit, was admitted to a ten-bed neurological intensive care unit of a tertiary care hospital. The patient developed consecutive multiple organ dysfunction with rhabdomyolysis, and hepatic and respiratory failure. Temperature elevation was resistant to conventional treatment measures. Aggressive intensive care treatment included forced diuresis and endovascular cooling to combat hyperthermia and maintain normothermia. RESULTS: Analyses of serum revealed elevation of proinflammatory cytokines (TNF alpha, IL-6), cytokines (IL-2R), anti-inflammatory cytokines (IL-4) and chemokines (IL-8) as well as signs of rhabdomyolysis and hepatic failure. Aggressive intensive care treatment as forced diuresis and endovascular cooling (CoolGard and CoolLine) to combat hyperthermia and maintain normothermia were used successfully to treat this severe heat stroke. CONCLUSION: In this case of severe heat stroke, presenting with multiple organ dysfunction and elevation of cytokines and chemokines, which was resistant to conventional cooling therapies, endovascular cooling may have contributed significantly to the reduction of body temperature and, possibly, avoided a fatal result.

Adult↗
PubMed2005

Voxel-based morphometry in narcolepsy.

BACKGROUND AND PURPOSE: Voxel-based morphometry (VBM) is a magnetic resonance imaging (MRI)-based indirect volumetry, which allows the investigation of the entire brain without restriction of predefined regions-of-interest. Recent studies using this technique reported controversial results in patients with narcolepsy. PATIENTS AND METHODS: In this study, 12 patients with narcolepsy according to the criteria of the International Classification of Sleep Disorders were compared to 12 age-matched controls with normal MR images using VBM. Sex and global differences in voxel intensities were used as confounding covariates. RESULTS: Significant gray matter loss was found in the right prefrontal and frontomesial cortex of patients with narcolepsy. White matter comparison revealed no significant changes in patients or controls. The comparison of cerebrospinal fluid partition detected an enlargement of subarachnoidal space of controls close to the prefrontal cortex. CONCLUSIONS: The volume reduction of gray matter in narcoleptic patients could indicate a disease-related atrophy pattern. However, the results of VBM studies in narcolepsy are contradictory. A possible systematic bias due to inhomogeneous patient groups, stimulant medication history or pre-statistical image processing must be considered. We suggest that studies with drug-naive patients and/or region-of-interest-based volumetric studies should be performed in areas defined by VBM.

Adult↗
PubMed2005

Voxel-wise analysis of [123I]beta-CIT SPECT differentiates the Parkinson variant of multiple system atrophy from idiopathic Parkinson's disease.

To investigate the cerebral dopamine transporter status in the early stages of the parkinson-variant of multiple system atrophy (MSA-P), 15 patients with MSA-P and a disease duration up to 3 years were studied with [123I]beta-CIT single photon emission computed tomography (SPECT). Data were compared with 13 age-matched healthy control subjects and 15 patients with idiopathic Parkinson's disease (IPD), matched for age and disease duration. Parametric SPECT images of the specific-to-nondisplaceable equilibrium partition coefficient (V3''), which is proportional to the receptor density (Bmax) have been generated. To objectively localize focal changes in dopaminergic function throughout the entire brain volume without having to make an a priori hypothesis as to their location, statistical parametric mapping (SPM) was applied to our [123I]beta-CIT SPECT study. Both MSA-P and IPD patients showed significant decreases in striatal [123I]beta-CIT SPECT uptake. However, in MSA-P patients an additional reduction in midbrain [123I]beta-CIT signal was localized with SPM compared with control subjects (MSA-P, V3'': 0.89 +/- 0.37 versus controls V3'': 1.81 +/- 0.38; P < 0.001) and patients with IPD (V3'': 1.84 +/- 0.26; P < 0.001). Stepwise linear discriminant analysis of mean [123I]beta-CIT uptake in the putamen, caudate and midbrain identified the caudate and midbrain as indices to classify correctly 95.2% of subjects as either normal, patients with MSA-P or IPD. Voxel-wise analysis of [123I]beta-CIT SPECT revealed more widespread decline of monoaminergic transporter availability in MSA-P compared with IPD, matching the underlying pathological features. We suggest that the quantification of midbrain DAT signal should be included in the routine clinical analysis of [123I]beta-CIT SPECT in patients with uncertain parkinsonism.

Aged↗
PubMed2005

Hippocampal formation involvement in a language-activation task in patients with mesial temporal lobe epilepsy.

PURPOSE: The study aims to explore the contribution of the hippocampal formation to the retained language-comprehension network in patients with unilateral mesial temporal lobe epilepsy (TLE). METHODS: We performed a functional magnetic resonance (MRI) study based on a language comprehension paradigm in 45 right-handed patients with unilateral mesial TLE and 35 healthy control subjects. Activations in the hippocampal formations in both hemispheres were analyzed for each subject as well as for groups of left TLE, right TLE, and controls. RESULTS: In sum, 82% of TLE patients displayed hippocampal activations. A significant difference in hippocampal activation between left and right TLE was found: Right TLE patients showed increased activity in the left hippocampal formation compared with left TLE patients. In contrast, patients with left TLE did not show increased activity in the right hippocampal formation compared with right TLE patients. In comparison with a healthy control group, right TLE patients activated the left hippocampal formation to a greater extent, whereas patients with left TLE did not activate the right hippocampal formation to a greater degree. These findings point to an increased involvement of the left hippocampal formation during a language-comprehension task in right TLE patients. In contrast, left TLE in right-handed patients seems not associated with an enhanced involvement of the right hippocampal formation in retained language comprehension. CONCLUSIONS: These findings suggest that effective language comprehension in right-handed subjects with TLE depends on the involvement of the left hippocampal formation and underline the risks of postoperative language decline in patients with left TLE.

Adolescent↗
PubMed2004

Basal forebrain atrophy is a distinctive pattern in dementia with Lewy bodies.

We determined brain atrophy patterns in dementia with Lewy bodies and Alzheimer's disease using voxel-based morphometry, an indirect volumetry. Ten patients with dementia with Lewy bodies, 10 patients with Alzheimer's disease and 10 controls were included. All groups were matched for age; sex and global differences in voxel intensities were included as confounding covariates. We observed basal forebrain atrophy discriminating dementia with Lewy bodies from Alzheimer's disease. Compared to controls, atrophy of lateral prefrontal cortex and left premotor cortex was seen in dementia with Lewy bodies whereas atrophy of the medial temporal cortex, posterior parietal cortex, thalamus and temporo-occipital areas was observed in Alzheimer's disease. Atrophy of insular cortex was found in both patient groups.

Aged↗
PubMed2004

Popeye domain containing gene 2 (Popdc2) is a myocyte-specific differentiation marker during chick heart development.

The Popeye domain containing (popdc) genes constitute a novel gene family encoding proteins of the plasma membrane in muscle cells, with three N-terminal transmembrane domains and a cytoplasmic carboxy terminus. In vertebrates, three members of the Popdc gene family have been described. However, in the chick system only two cDNAs, Popdc1 and Popdc3, have been cloned previously. By screening a chick expressed sequence tag database, we report here the identification of five alternatively spliced chick Popdc2 cDNAs with different carboxy termini. Northern blot analysis revealed expression of Popdc2 predominantly in the myocardium and weaker expression in skeletal muscle. By whole-mount in situ hybridization, chick Popdc2 was first detected at Hamburger and Hamilton (HH) stage 7 within the anterior part of the heart fields. In the tubular heart, atrial and ventricular precursor cells stained positively for Popdc2. Weaker expression was observed in myocardium of the outflow tract and sinus venosus. By HH stage 18, the outer curvature myocardium was strongly stained, whereas expression in myocardium of the inner curvature was negligible. Popdc2 expression was absent from the endocardium and propepicardial organ. At HH stage 36, Popdc2 expression was confined to the compact layer myocardium. In addition to the heart, Popdc2 expression was also observed in the myotome and in the muscle-forming fields of the limbs. Our results indicate that Popdc2 is highly expressed in the developing heart and may serve as a novel marker of myocardial differentiation in the chick embryo.

Alternative Splicing↗