Showing papers by "Ruth H. Walker published in 2003"
TL;DR: Examination of the effects of levodopa on dopamine neurons in mesencephalic cultures and rat pups in which glutathione synthesis has been inhibited byl-buthionine sulfoximine provides further evidence to support the notion that although levodopamine can be toxic to dopamine neuron in vitro, it is not likely to be toxic in vivo and specifically in conditions such as PD.
Abstract: Levodopa is the "gold standard" for the symptomatic treatment of Parkinson's disease (PD). There is a theoretical concern, however, that levodopa might accelerate the rate of nigral degeneration, because it undergoes oxidative metabolism and is toxic to cultured dopaminergic neurons. Most in vivo studies do not show evidence of levodopa toxicity; levodopa is not toxic to normal rodents, nonhuman primates, or humans and is not toxic to dopamine neurons in dopamine-lesioned rodents or nonhuman primates in most studies. However, the potential for levodopa to be toxic in vivo has not been tested under conditions of oxidative stress such as exist in PD. To assess whether levodopa is toxic under these circumstances, we have examined the effects of levodopa on dopamine neurons in mesencephalic cultures and rat pups in which glutathione synthesis has been inhibited by L-buthionine sulfoximine. Levodopa toxicity to cultured dopaminergic neurons was enhanced by glutathione depletion and diminished by antioxidants. In contrast, treatment of neonatal rats with levodopa, administered either alone or in combination with glutathione depletion, did not cause damage to the dopamine neurons of the substantia nigra or changes in striatal levels of dopamine and its metabolites. This study provides further evidence to support the notion that although levodopa can be toxic to dopamine neurons in vitro, it is not likely to be toxic to dopamine neurons in vivo and specifically in conditions such as PD.
90 citations
TL;DR: Three patients from a previously described family with autosomal dominant chorea-acanthocytosis were found to have the CTG trinucleotide repeat expansion mutation of the junctophilin-3 gene associated with Huntington’s disease–like 2 (HDL2).
Abstract: Three patients from a previously described family with autosomal dominant chorea-acanthocytosis were found to have the CTG trinucleotide repeat expansion mutation of the junctophilin-3 gene associated with Huntington's disease-like 2 (HDL2). One of six previously identified patients with HDL2 had acanthocytosis on peripheral blood smear, suggesting that HDL2 should be considered in the differential of chorea-acanthocytosis.
76 citations
TL;DR: This work highlights the clinical features of this disorder, including chorea, dystonia, parkinsonism, and cognitive deficits, and highlights the need to understand and treat these features more fully.
Abstract: Huntington's disease-like 2 is an autosomal dominantly inherited disorder due to an expansion of trinucleotide repeats. It resembles classic Huntington's disease in clinical phenotype, inheritance pattern, and neuropathological features. We highlight the clinical features of this disorder, including chorea, dystonia, parkinsonism, and cognitive deficits.
61 citations
TL;DR: Examining cases of Huntington's disease, spinocerebellar ataxia type III, and Huntington’s disease‐like 2 using antibodies to torsinA found that ubiquitinated, intranuclear neuronal inclusions were torsInA‐immunoreactive, possibly indicating a role for tors in protein degradation.
Abstract: A mutation of the DYT1 gene, which codes for torsinA, has been identified as a cause of autosomal dominantly inherited dystonia. The function of torsinA is not yet known, but it is found throughout the central nervous system and has been identified in Lewy bodies in Parkinson's disease. We examined cases of Huntington's disease, spinocerebellar ataxia type III, and Huntington's disease-like 2 using antibodies to torsinA, and found that ubiquitinated, intranuclear neuronal inclusions were torsinA-immunoreactive, possibly indicating a role for torsinA in protein degradation. © 2003 Movement Disorder Society
26 citations
TL;DR: A functional interference with neuronal signal processing induced by mutation of torsinA is consistent with current hypotheses regarding impairment of the center‐surround mechanism in the striatum.
Abstract: The identification of a mutation of the DYT1 gene as a cause of inherited dystonia has led to many insights regarding the genetics of this disorder. In addition, there is a rapidly expanding list of inherited dystonia syndromes, the genes for some of which have been identified or localized. The DYT1 mutation has been found in a variety of ethnic groups, and it may result in a range of phenotypes. To date, studies of torsinA, the protein product of the DYT1 gene, have not revealed its function, although its widespread distribution throughout the central nervous system suggests a universal role. TorsinA has structural homology to heat shock and chaperone proteins. Evidence from studies in cell cultures and Caenorhabditis elegans, and the presence of torsinA in inclusion bodies in several neurodegenerative diseases may be indicative of a function of this nature. Preliminary studies in humans with DYT1 dystonia and in DYT1 transgenic mice suggest disruption of the dopaminergic nigrostriatal system. A functional interference with neuronal signal processing induced by mutation of torsinA is consistent with current hypotheses regarding impairment of the center-surround mechanism in the striatum. © 2003 Movement Disorder Society
19 citations