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Biomedical subjects

Andreas Kupsch

Publications and source records attributed to Andreas Kupsch.

48 records · Page 3Linked to original sources
PubMed2004

Levodopa therapy with entacapone in daily clinical practice: results of a post-marketing surveillance study.

The catechol-O-methyl transferase inhibitor entacapone is given in combination with levodopa/dopa decarboxylase inhibitor for Parkinson's disease (PD) patients experiencing end-of-dose wearing-off. This 4-week post-marketing surveillance study was undertaken to assess patients' responses to levodopa combined with entacapone in a real clinical practice setting. Overall, 466 patients with idiopathic PD treated with levodopa and experiencing symptoms of wearing-off were recruited. Both physicians and patients recorded the response to therapy, including improvements and side-effects. Following initiation of entacapone treatment, the average daily levodopa dose was reduced from 510 to 453 mg. Physician assessment of entacapone efficacy was judged to be "very good" or "good" in 77.6% of the patients, and tolerability was considered to be "very good" or "good" in 92.4% of patients, with only 12 patients (2.6%) withdrawing from the study. Compared with baseline, there was a decrease in the mean duration of daily 'off' time from 3.0 to 1.3 h per day during the treatment period. Adverse events were in line with those previously reported, with diarrhoea being the most frequent event. The percentage of patients suffering from dyskinesia decreased from 46 to 34%, and of those patients still suffering from dyskinesia, the average daily duration of dyskinesia was reduced from 2.2 to 1.7 h. The use of adjunct dopamine agonists decreased from 67 to 59%. At study end, the percentage of patients who rated their quality of life (QoL) as "very good" or "good" increased from 12.1 to 51.7% and the percentage of patients who rated their QoL as "bad" or "very bad" decreased from 40 to 10.7%. In summary, the results of this survey conducted in real clinical practice support the findings of previous clinical trials demonstrating the efficacy and tolerability of entacapone, as well as the benefits of improved QoL, for patients achieved with entacapone.

Adult↗
PubMed2003

Comparison of motor effects following subcortical electrical stimulation through electrodes in the globus pallidus internus and cortical transcranial magnetic stimulation.

Current concepts of transcranial magnetic stimulation (TMS) over the primary motor cortex are still under debate as to whether inhibitory motor effects are exclusively of cortical origin. To further elucidate a potential subcortical influence on motor effects, we combined TMS and unilateral subcortical electrical stimulation (SES) of the corticospinal tract. SES was performed through implanted depth electrodes in eight patients treated with deep brain stimulation (DBS) for severe dystonia. Chronaxie, conduction velocity (CV) of the stimulated fibres and poststimulus time histograms of single motor unit recordings were calculated to provide evidence of an activation of large diameter myelinated fibres by SES. Excitatory and inhibitory motor effects recorded bilaterally from the first dorsal interosseus muscle were measured after SES and focal TMS of the motor cortex. This allowed us to compare motor effects of subcortical (direct) and cortical (mainly indirect) activation of corticospinal neurons. SES activated a fast conducting monosynaptic pathway to the alpha motoneuron. Motor responses elicited by SES had significantly shorter onset latency and shorter duration of the contralateral silent period compared to TMS induced motor effects. Spinal excitability as assessed by H-reflex was significantly reduced during the silent period after SES. No ipsilateral motor effects could be elicited by SES while TMS was followed by an ipsilateral inhibition. The results suggest that SES activated the corticospinal neurons at the level of the internal capsule. Comparison of SES and TMS induced motor effects reveals that the first part of the TMS induced contralateral silent period should be of spinal origin while its later part is due to cortical inhibitory mechanisms. Furthermore, the present results suggest that the ipsilateral inhibition is predominantly mediated via transcallosal pathways.

Adolescent↗
PubMed2003

Patterning of globus pallidus local field potentials differs between Parkinson's disease and dystonia.

Here we test the hypothesis that there are distinct temporal patterns of synchronized neuronal activity in the pallidum that characterize untreated and treated parkinsonism and dystonia. To this end we recorded local field potentials (LFPs) from the caudal and rostral contact pairs of macroelectrodes implanted into the pallidum of patients for the treatment of Parkinson's disease (12 cases recorded on and off medication, 17 macroelectrodes) and dystonia (10 cases, 19 macroelectrodes). Percentage LFP power in the 11-30 Hz band was decreased and that in the 4-10 Hz band increased across both contact pairs in treated Parkinson's disease compared with untreated Parkinson's disease. Dystonic patients had even less 11-30 Hz power and greater 4-10 Hz power compared with untreated or treated Parkinson's disease patients. The change in the 4-10 Hz band in patients with dystonia was particularly manifest in the more rostral contact pair, presumed to be within or bridging the globus pallidus externus. We conclude that untreated and treated Parkinson's disease and dystonia are characterized by different spatiotemporal patterns of activity in the human pallidum.

Adult↗
PubMed2003

Behavioural cues are associated with modulations of synchronous oscillations in the human subthalamic nucleus.

The speed with which one reacts to an imperative signal depends on the extent to which preceding cues predict that command. When reliable warning cues are available, the processing of the imperative stimulus can be favoured and responses partially pre-prepared, leading to shorter reaction times. Here we seek evidence for involvement of the human basal ganglia in the exploitation of behaviourally relevant predictive cues. To this end, local field potentials (LFPs) were recorded in the region of the subthalamic nuclei of parkinsonian patients during the performance of a pre-cued reaction task in which the cue either predicted or failed to predict the demands of the imperative signal. We demonstrate that LFP activity in the beta frequency band ( approximately 20 Hz) is modulated by the behavioural relevance of the external cue. The findings suggest that, first, the subthalamic nucleus is involved in mediating or facilitating the response advantage derived from predictive cues in humans and, secondly, variations in synchronous neuronal activity in the beta band may contribute to this function in the subthalamic nucleus.

Aged↗
PubMed2003

Absorption and extinction correction in quantitative DAFS analysis.

An approach to X-ray attenuation correction for diffraction anomalous fine-structure (DAFS) measurements is presented, taking into account energy-dependent secondary extinction effects. A numerical model based on the kinematical theory of diffraction is presented. This model is exemplified by DAFS measurements of the Zr 0002 reflection intensities for energies in the vicinity of the Zr K absorption edge of a Co/Zr multilayer exhibiting strong fibre texture. X-ray absorption fine-structure (XAFS) measurements proved to be a necessary auxiliary for DAFS amplitude correction.

Journal Article↗
PubMed2003

Deep brain stimulation in dystonia.

Renewed interest in stereotaxy for dystonia followed the introduction of deep brain stimulation (DBS) in Parkinson's disease and essential tremor in the 1990s. DBS evolved from ablative surgery, which was applied with varying results in the 1950s in patients with movement disorders such as Parkinson's disease, essential tremor and dystonia. The present review summarizes the current knowledge on clinical aspects of DBS in dystonia (Dec. 2002). Excellent results have been achieved in dystonic patients carrying a mutation in the DYT1 gene with improvements up to 90 %. Similar results may also be obtained in patients with idiopathic generalized dystonia, myoclonus-dystonia syndrome, and tardive dystonia. Substantial improvement has been observed in patients with focal dystonia (for instance cervical dystonia). Patients with secondary dystonia often display a lesser and more variable degree of improvement. Long-term studies are warranted to assess both motor and neuropsychological sequelae of DBS in dystonia. Furthermore, the optimal target for different dystonic disorders remains to be determined, although the globus pallidus internus has currently emerged as the most promising target for dystonia.

Dystonia↗
PubMed2003

High-frequency stimulation of the subthalamic nucleus enhances striatal dopamine release and metabolism in rats.

High-frequency stimulation of the subthalamic nucleus is believed to exert its main effects via the basal ganglia output structures. Previously, we have shown a concomitant increase in striatal dopamine (DA) metabolites in normal and 6-hydroxydopamine-lesioned rats. The present study was designed to determine whether this increase in striatal DA metabolites reflects enhanced intraneuronal DA turnover or, alternatively, is due to increased DA release with subsequent rapid and efficient reuptake and/or metabolism. Thus, high-frequency stimulation of the subthalamic nucleus was performed in normal rats after inhibition of DA reuptake, metabolism or DA depletion. Extracellular levels of striatal DA and its metabolites were assessed using microdialysis. Our data suggest that subthalamic high-frequency stimulation increases striatal DA release and activates independent striatal DA metabolism. Since such changes could be triggered by modification of either the activity or the gene expression of the rate-limiting enzyme tyrosine hydroxylase, an activity assay and RT-PCR of striatal and nigral samples were performed. Subthalamic stimulation increased striatal tyrosine hydroxylase activity without affecting gene expression. We, therefore, conclude that the application of subthalamic high-frequency stimulation could partially compensate for the DA deficit by inducing increased striatal DA release and metabolism.

Animals↗
PubMed2002

Deep brain stimulation of subthalamic neurons increases striatal dopamine metabolism and induces contralateral circling in freely moving 6-hydroxydopamine-lesioned rats.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) alleviates Parkinson's disease (PD) symptoms. Although widely used, the mechanisms of action are still unknown. In an attempt to elucidate those mechanisms, we have previously demonstrated that STN-DBS increases striatal extracellular dopamine (DA) metabolites in anaesthetized rats. PD being a movement disorder, it remains to be determined whether these findings are related to any relevant motor or behavioural changes. Thus, this study investigates concomitant behavioural changes during STN-DBS and extracellular striatal DA metabolites measured using microdialysis in freely moving 6-hydroxydopamine-lesioned rats. STN-DBS induced an increase of striatal DA metabolites in awake, freely moving animals. Furthermore, we observed concomitant contralateral circling behaviour. Taken together, these results suggest that STN-DBS could disinhibit (consequently activate) substantia nigra compacta neurons via inhibition of gamma-aminobutyric acid-ergic substantia nigra reticulata neurons.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2002

Myoclonus-dystonia syndrome: epsilon-sarcoglycan mutations and phenotype.

Mutations in the gene for epsilon-sarcoglycan (SGCE) have been found to cause myoclonus-dystonia syndrome. We now report clinical and genetic findings in nine additional European families with myoclonus-dystonia syndrome. The clinical presentation in 24 affecteds was homogeneous with myoclonus predominantly of neck and upper limbs in 23 of them and dystonia, presenting as cervical dystonia and/or writer's cramp, in 13 cases. Six novel and one previously known heterozygous SGCE mutations were identified. SGCE deficiency seems to be the common pathogenetic mechanism in myoclonus-dystonia syndrome.

Adolescent↗
PubMed2002

Oscillatory local field potentials recorded from the subthalamic nucleus of the alert rat.

Hitherto, high-frequency local field potential oscillations in the upper gamma frequency band (40-80 Hz) have been recorded only from the region of subthalamic nucleus (STN) in parkinsonian patients treated with levodopa. Here we show that local field potentials recorded from the STN in the healthy alert rat also have a spectral peak in the upper gamma band (mean 53 Hz, range 46-70 Hz). The power of this high-frequency oscillatory activity was increased by 30 +/- 4% (+/-SEM) during motor activity compared to periods of alert immobility. It was also increased by 86 +/- 36% by systemic injection of the D2 dopamine receptor agonist quinpirole. The similarities between the high-frequency activities in the STN of the healthy rat and in the levodopa-treated parkinsonian human argue that this oscillatory activity may be physiological in nature and not a consequence of the parkinsonian state.

Animals↗
PubMed2002

Rasagiline. Teva Pharmaceutical.

Rasagiline is a selective and potent irreversible MAO(B) inhibitor which is under development by Teva for the treatment of neurological diseases. Rasagiline is in phase III trials in the US, Canada and Europe for Parkinson's disease (PD) and has completed phase II trials in Israel and Hungary. Teva planned to submit a filing in 2002 and expected to launch rasagiline in 2003. Lundbeck acquired European development and commercialization rights to rasagiline in November 1999 and, in September 2001, the company reported that it planned to file an NDA in 2003. In March 2002, analysts at Morgan Stanley Dean Witter predicted that H Lundbeck would make sales of rasagiline of DKr 100 million in 2003, rising to DKr 300 million in 2008. In the same month, launch was predicted in 2004/2005 for the PD indication, and 2005/2006 for the AD indication, by analysts at Deutsche Banc Alex Brown.

Administration, Oral↗