Publications by authors named "Vincent Ries"

The polypeptide ghrelin is an endogenous ligand at the growth hormone secretagogue receptor 1a. To ghrelin multiple functions have been ascribed including promotion of gastrointestinal motility. Postprandial ghrelin levels have been reported to be reduced in patients suffering from Parkinson disease (PD).

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Augmented spinal nociception during the "off" phase has been observed early in Parkinson's disease further increasing with disease duration. To find out whether increased spinal nociception represents a premotor feature, experimental pain sensitivity was assessed in idiopathic REM-sleep behavior disorder (IRBD) patients with or without signs of a neurodegenerative disorder compared to early Parkinson's disease (ePD) patients and healthy controls (HC). Spinal nociception as measured by the nociceptive flexion reflex (NFR) and experimental pain sensitivity as measured by heat and electrical pain thresholds were determined in 14 IRBD, 15 ePD patients in the medication-defined "off" state and 27 HC in an explorative cohort study.

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Parkinson's disease (PD) is a frequent neurodegenerative process in old age. Accumulation and aggregation of the lipid-binding SNARE complex component α-synuclein (SNCA) underlies this vulnerability and defines stages of disease progression. Determinants of SNCA levels and mechanisms of SNCA neurotoxicity have been intensely investigated.

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Parkinson disease (PD) is a neurodegenerative disorder characterized by massive loss of midbrain dopaminergic neurons. Whereas onset of motor impairments reflects a rather advanced stage of the disorder, hyposmia often marks the beginning of the disease. Little is known about the role of the nigro-striatal system in olfaction under physiological conditions and the anatomical basis of hyposmia in PD.

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Gain-of-function mutations of alpha-synuclein (SNCA) are known to trigger Parkinson's disease (PD) with striatal dopaminergic deficits and a reduction of spontaneous movements. The longest size variant (allele 2) of the complex microsatellite repeat Rep1 within the SNCA gene promoter is known to confer a PD risk. We now observed this Rep1 allele 2 to show significantly decreased frequency in restless legs syndrome (RLS) in a genotyping study of 258 patients versus 235 healthy controls from Germany.

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Olfactory dysfunction, often preceding the cardinal motor symptoms, such as bradykinesia, rigidity, tremor at rest and postural instability, is frequently reported in Parkinson's disease. This symptom appears to be related to an increased number of dopamine neurons in the periglomerular layer of the olfactory bulb. In animal models of Parkinson's disease, adult neural progenitor cells migrating from the subventricular zone of the lateral ventricle to the olfactory bulb are evidently altered in their survival and progeny.

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We report on two pregnant women who either had de novo restless legs syndrome (RLS) or had marked enhancement of preexisting RLS symptoms during pregnancy. Both patients had ferritin values <50 μg/L at baseline. The patients had relevant sleep disorders and daytime symptoms caused by RLS.

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Progressive supranuclear palsy (PSP) is a sporadic and progressive neurodegenerative disease, most often leading to a symmetric, akinetic-rigid syndrome with prominent postural instability, vertical supranuclear gaze palsy, and cognitive decline. It belongs to the family of tauopathies and involves both cortical and subcortical structures. There is evidence from laboratory as well as in vivo studies suggesting that mitochondrial energy metabolism is impaired in PSP.

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The mechanisms underlying the chronic neurodegeneration that occurs in Parkinson's disease (PD) are unknown. One emerging hypothesis is that neural systems deteriorate and eventually degenerate due to a primary failure of either extrinsic neurotrophic support or the intrinsic cellular pathways that mediate such support. One of the cellular pathways that have been often identified in mediating neurotrophic effects is that of PI3K/Akt signaling.

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Study objectives were to assess the efficacy, safety, and tolerability of AFQ056 in Parkinson's disease patients with levodopa-induced dyskinesia. Two randomized, double-blind, placebo-controlled, parallel-group, in-patient studies for Parkinson's disease patients with moderate to severe levodopa-induced dyskinesia (study 1) and severe levodopa-induced dyskinesia (study 2) on stable dopaminergic therapy were performed. Patients received 25-150 mg AFQ056 or placebo twice daily for 16 days (both studies).

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Objective: This study investigated the feasibility, safety, and potential benefit in motor symptom control when switching from a dopamine agonist to tolcapone as an adjunctive therapy in patients with Parkinson's disease with a fluctuating response to levodopa (l-dopa). We determined the efficacy of 2 replacement strategies.

Methods: In this 10-week, randomized, open-label, stratified, parallel-group trial, 150 patients on a stable regimen of l-dopa/decarboxylase inhibitor in combination with bromocriptine, lisuride, or pergolide were switched to tolcapone.

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Following mitosis, specification and migration during embryogenesis, dopamine neurons of the mesencephalon undergo a postnatal naturally occurring cell death event that determines their final adult number, and a period of axonal growth that determines pattern and extent of target contacts. While a number of neurotrophic factors have been suggested to regulate these developmental events, little is known, especially in vivo, of the cell signaling pathways that mediate these effects. We have examined the possible role of Akt/Protein Kinase B by transduction of these neurons in vivo with adeno-associated viral vectors to express either a constitutively active or a dominant negative form of Akt/protein kinase B.

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Activation of c-jun N-terminal kinase (JNK) by the mitogen-activated protein kinase cascade has been shown to play an important role in the death of dopamine neurons of the substantia nigra, one of the principal neuronal populations affected in Parkinson's disease. However, it has remained unknown whether the JNK2 and JNK3 isoforms, either singly or in combination, are essential for apoptotic death, and, if so, the mechanisms involved. In addition, it has been unclear whether they play a role in axonal degeneration of these neurons in disease models.

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Despite promising preclinical studies, neurotrophic factors have not yet achieved an established role in the treatment of human neurodegenerative diseases. One impediment has been the difficulty in providing these macromolecules in sufficient quantity and duration at affected sites. An alternative approach is to directly activate, by viral vector transduction, intracellular signaling pathways that mediate neurotrophic effects.

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There is increasing evidence that neuron death in neurodegenerative diseases, such as Parkinson's disease, is due to the activation of programmed cell death. However, the upstream mediators of cell death remain largely unknown. One approach to the identification of upstream mediators is to perform gene expression analysis in disease models.

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There is increasing evidence that glial cell line-derived neurotrophic factor (GDNF) plays a role as a limiting, striatal target-derived neurotrophic factor for dopamine neurons of the substantia nigra pars compacta (SNpc) by regulating the magnitude of the first phase of postnatal natural cell death which occurs in these neurons. While it has been shown that GDNF mRNA is relatively abundant in postnatal striatum, the cellular basis of its expression has been unknown. We therefore used nonradioactive in situ hybridization and immunohistochemistry to examine the cellular basis of GDNF mRNA and protein expression, respectively, in postnatal striatum and related structures.

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Because Parkinsonism is underdiagnosed in the community, we have validated screening modalities in the field setting and developed a screening procedure to enhance recognition of undiagnosed patients. In a first survey, we identified suspect cases among patients consulting 9 general practitioners (GPs) over a 3-week period using in parallel: (1) a published questionnaire; (2) a standardized examination by the GPs; (3) clinical impression of the GPs; or (4) pre-established diagnoses. Parkinsonism was ascertained by two neurologists with a 1-year follow-up and FP-CIT-SPECT.

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