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A Colcher

Publications and source records attributed to A Colcher.

14 recordsLinked to original sources
PubMed2003

Genetic polymorphisms of the N-acetyltransferase genes and risk of Parkinson's disease.

Recently, the authors demonstrated linkage in idiopathic PD to a region on chromosome 8p that contains the N-acetyltransferase genes, NAT1 and NAT2. The authors examined NAT1 and NAT2 for association with PD using family-based association methods and single nucleotide polymorphisms (SNPs). The authors did not find evidence for association with increased risk for PD between any individual NAT1 or NAT2 SNP or acetylation haplotype (N = 397 families, 1,580 individuals).

Aged↗
PubMed2001

Complete genomic screen in Parkinson disease: evidence for multiple genes.

CONTEXT: The relative contribution of genes vs environment in idiopathic Parkinson disease (PD) is controversial. Although genetic studies have identified 2 genes in which mutations cause rare single-gene variants of PD and observational studies have suggested a genetic component, twin studies have suggested that little genetic contribution exists in the common forms of PD. OBJECTIVE: To identify genetic risk factors for idiopathic PD. DESIGN, SETTING, AND PARTICIPANTS: Genetic linkage study conducted 1995-2000 in which a complete genomic screen (n = 344 markers) was performed in 174 families with multiple individuals diagnosed as having idiopathic PD, identified through probands in 13 clinic populations in the continental United States and Australia. A total of 870 family members were studied: 378 diagnosed as having PD, 379 unaffected by PD, and 113 with unclear status. MAIN OUTCOME MEASURES: Logarithm of odds (lod) scores generated from parametric and nonparametric genetic linkage analysis. RESULTS: Two-point parametric maximum parametric lod score (MLOD) and multipoint nonparametric lod score (LOD) linkage analysis detected significant evidence for linkage to 5 distinct chromosomal regions: chromosome 6 in the parkin gene (MLOD = 5.07; LOD = 5.47) in families with at least 1 individual with PD onset at younger than 40 years, chromosomes 17q (MLOD = 2.28; LOD = 2.62), 8p (MLOD = 2.01; LOD = 2.22), and 5q (MLOD = 2.39; LOD = 1.50) overall and in families with late-onset PD, and chromosome 9q (MLOD = 1.52; LOD = 2.59) in families with both levodopa-responsive and levodopa-nonresponsive patients. CONCLUSIONS: Our data suggest that the parkin gene is important in early-onset PD and that multiple genetic factors may be important in the development of idiopathic late-onset PD.

Adult↗
PubMed2001

Association of single-nucleotide polymorphisms of the tau gene with late-onset Parkinson disease.

CONTEXT: The human tau gene, which promotes assembly of neuronal microtubules, has been associated with several rare neurologic diseases that clinically include parkinsonian features. We recently observed linkage in idiopathic Parkinson disease (PD) to a region on chromosome 17q21 that contains the tau gene. These factors make tau a good candidate for investigation as a susceptibility gene for idiopathic PD, the most common form of the disease. OBJECTIVE: To investigate whether the tau gene is involved in idiopathic PD. DESIGN, SETTING, AND PARTICIPANTS: Among a sample of 1056 individuals from 235 families selected from 13 clinical centers in the United States and Australia and from a family ascertainment core center, we tested 5 single-nucleotide polymorphisms (SNPs) within the tau gene for association with PD, using family-based tests of association. Both affected (n = 426) and unaffected (n = 579) family members were included; 51 individuals had unclear PD status. Analyses were conducted to test individual SNPs and SNP haplotypes within the tau gene. MAIN OUTCOME MEASURE: Family-based tests of association, calculated using asymptotic distributions. RESULTS: Analysis of association between the SNPs and PD yielded significant evidence of association for 3 of the 5 SNPs tested: SNP 3, P =.03; SNP 9i, P =.04; and SNP 11, P =.04. The 2 other SNPs did not show evidence of significant association (SNP 9ii, P =.11, and SNP 9iii, P =.87). Strong evidence of association was found with haplotype analysis, with a positive association with one haplotype (P =.009) and a negative association with another haplotype (P =.007). Substantial linkage disequilibrium (P<.001) was detected between 4 of the 5 SNPs (SNPs 3, 9i, 9ii, and 11). CONCLUSIONS: This integrated approach of genetic linkage and positional association analyses implicates tau as a susceptibility gene for idiopathic PD.

Age of Onset↗
PubMed2001

A randomized, controlled trial of remacemide for motor fluctuations in Parkinson's disease.

BACKGROUND: Preclinical studies suggest that glutamate antagonists help ameliorate motor fluctuations in patients with PD treated with levodopa. METHODS: In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study, the authors assessed the safety, tolerability, and efficacy of the glutamate receptor blocker remacemide hydrochloride in 279 patients with motor fluctuations treated with levodopa. The primary objective was to assess the short-term tolerability and safety of four dosage levels of remacemide during 7 weeks of treatment. Patients were also monitored with home diaries and the Unified PD Rating Scale (UPDRS) to collect preliminary data on treatment efficacy. RESULTS: Remacemide was well tolerated up to a dosage of 300 mg/d on a twice daily schedule and 600 mg/d on a four times daily schedule. The most common dosage-related adverse events were dizziness and nausea, as observed in previous studies of remacemide. The percent "on" time and motor UPDRS scores showed trends toward improvement in the patients treated with 150 and 300 mg/d remacemide compared with placebo-treated patients, although these improvements were not significant. CONCLUSION: Remacemide is a safe and tolerable adjunct to dopaminergic therapy for patients with PD and motor fluctuations. Although this study had limited power to detect therapeutic effects, the observed improvement is consistent with studies of non-human primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian signs and symptoms. Additional studies are warranted to confirm these results over an extended period of observation, and to explore the potential neuroprotective effects of remacemide in slowing the progression of PD.

Acetamides↗
PubMed2001

Repetitive proximal esophageal contractions: a new manometric finding and a possible further link between Parkinson's disease and achalasia.

Repetitive, spontaneous contractions of the proximal esophagus have recently been identified as a feature of achalasia. This article documents similar findings in six patients with Parkinson's disease. Parkinson's disease and achalasia share many common features neurologically. Both have Lewy bodies in the esophageal myenteric plexuses and the substantia nigra, in addition to evidence of degeneration of the dorsal motor nucleus of the vagus. The esophageal features radiologically and manometrically are also similar. Repetitive proximal esophageal contractions may represent another link between these diseases. They have also been reported in scleroderma. We speculate that the common link between all three disease processes may be poor distensibility of the esophagus.

Aged↗
PubMed2001

Other Parkinson syndromes.

The etiology of parkinsonism is varied. Symptomatic parkinsonism is seen in the setting of genetic disorders, infectious processes, structural lesions, and as a result of concomitant medications. A thorough history and good examination will differentiate PD from the diverse group of conditions that can mimic it.

Diagnosis, Differential↗
PubMed2001

Manometric abnormalities of the oesophagus in patients with Parkinson's disease.

Dysphagia in Parkinson's disease (PD) is known to correlate with abnormalities of oropharyngeal function. Oesophageal abnormalities have not been previously demonstrated to correlate with dysphagia. The aim of the study was to determine if motor dysfunction of the oesophageal body correlates with dysphagia or disease severity in PD. Twenty-two patients with PD were assessed for the severity of their dysphagia (scale of 1-7) and severity of PD (Hoehn and Yahr scale 1-4). All underwent oesophageal manometry. Dysphagia was present daily in 10 patients (45%). Parkinson's disease was graded as severe (Hoehn and Yahr > or =3) in eight (36%) patients. Oesophageal manometry was abnormal in 16 (73%) patients. Thirteen patients had either complete aperistalsis or multiple simultaneous contractions (diffuse oesophageal spasm). These findings were significantly more common in patients with daily dysphagia (90% vs. 33%; P < 0.005), and were not related to duration or severity of PD. We conclude that the presence of aperistalsis or multiple simultaneous contractions in the oesophagus does correlate with dysphagia and is independent of PD severity or duration. This may reflect selective involvement of either the dorsal motor nucleus of the vagus or the oesophageal myenteric plexus.

Aged↗
PubMed1999

Clinical manifestations of Parkinson's disease.

Although the clinical manifestations of PD remain similar to those described by Parkinson in the nineteenth century, knowledge of associated findings has increased dramatically. The ability to characterize the myriad of findings associated with PD enables clinicians to care better for patients with PD. Knowledge of the associated symptoms as well as the cardinal manifestations allows clinicians to target treatment to specific symptoms and thereby improve the quality of life of those affected with PD.

Activities of Daily Living↗
PubMed1999

Targeting for thalamic deep brain stimulator implantation without computer guidance: assessment of targeting accuracy.

The authors assess the accuracy of targeting nucleus ventralis intermedius (Vim) with fast spin echo inversion recovery (FSE/IR) magnetic resonance imaging (MRI) in 18 successful deep brain stimulator (DBS) implants for medically refractory tremor. FSE/IR-MRI-derived coordinates are compared to the final coordinates employed for DBS lead placement, selected with intraoperative neurophysiology. The authors conclude that FSE/IR MRI is sufficiently reliable to serve as the sole means of anatomically targeting Vim for DBS lead placement. An independent computer workstation is not required for accurate targeting; however, intraoperative neurophysiology remains essential.

Brain Mapping↗
PubMed1999

Movement disorders.

Movement disorders cause difficulty with ambulation. Hypokinetic disorders produce a slow gait with short strides and impairment of balance. The hyperkinetic disorders are also marked by an impairment of balance, caused by rapid or uncontrollable movements of the limbs or trunk, that interferes with the normal rhythm of walking. The gaits of different movement disorders help the clinician to classify them. Appropriate diagnosis and treatment of the disorder may significantly improve ambulation and quality of life.

Gait↗
PubMed1997

Comparison of swallowing function in Parkinson's disease and progressive supranuclear palsy.

Dysphagia is common in both Parkinson's disease (PD) and progressive supranuclear palsy (PSP). Although it is believed to be more common in PSP, there are no controlled data and no comparison of swallowing function between these two disorders. Our aim was to assess dysphagia and swallow function in patients with PSP and PD. Seven patients with PSP were matched to seven patients with PD on the basis of disease duration. Self-rated dysphagia, movement disorder disability, modified barium swallow results, and abnormalities noted on manometry of the lower esophageal sphincter, esophageal body, upper esophageal sphincter, and pharynx were compared between the two groups. Neither severity nor duration of dysphagia differed between the two groups. Patients with PSP had a significantly greater degree of disability [median (range) Hoehn & Yahr score, 4 (3-5) vs. 2 (1-2); P < 0.002]. Manometric abnormalities were similar for the two groups. Oral-phase abnormalities on modified barium swallow were significantly more frequent in PSP (four patients with PSP vs. no patients with PD; p < 0.005). Pharyngeal abnormalities did not differ. Modified barium-swallow scores correlated well with self-reported dysphagia severity for patients with PSP (r = 0.93; p < 0.05) but not for those with PD (r = 0.42; p = NS). The frequency of abnormalities noted during the oral phase was significantly increased in PSP. It is hypothesized that the sensory information conveyed due to this may account for the better correlation between symptoms and swallowing abnormalities and the belief that swallowing problems are more common in PSP.

Barium↗
PubMed1995

Therapy guided by symptoms for Parkinson's disease.

Low-dose combinations of medications that work in slightly different ways constitute optimal management of Parkinson's disease. Surgical approaches are being perfected for patients who stop responding favorably to pharmacologic treatment.

Humans↗