Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent imaging studies suggest a rapid degeneration of the dopaminergic system in early Parkinson's disease (PD), followed by a slowing of the degenerative process in advanced disease. In the present study, a group of early-stage PD patients underwent three sequential [123I]beta-CIT SPECT studies to assess the decline of striatal dopamine transporter binding over a 5-year period. Twenty-one of a cohort of 24 early PD patients who participated in an earlier longitudinal beta-CIT SPECT imaging study [Mov Disord 2002;17:45-53] were included. Scan intervals were 26 +/- 11 months (scan 1-2) and 38 +/- 15 months (scan 2-3), respectively. The relative annual rate of decline of striatal beta-CIT binding from age-expected normal values at the time of Scan 1 was used as primary outcome variable. The relative annual decline of striatal binding from Scan 1 to Scan 2 (4.5 +/- 4.6%) and from Scan 2 to Scan 3 (3.0 +/- 3.0%) was not significantly different. The non-significant difference in progression rate was due mainly to the rapid early decline of striatal binding in 1 patient who subsequently developed a severe dysexecutive dementia syndrome. These data are not suggestive of substantial change in the course of dopaminergic degeneration in PD within the first 5 to 7 years after symptom onset.
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PMID:Measuring the rate of progression of Parkinson's disease over a 5-year period with beta-CIT SPECT. 1463 66

Levodopa pharmacokinetic-phamacodynamic (PK-PD) modeling may be able to test the functional integrity of the nigrostriatal dopaminergic system in Parkinson's disease (PD). [(123)I]-FP-CIT SPECT imaging of striatal dopamine transporters has also been introduced for the evaluation of presynaptic dopaminergic homeostasis. We aimed to assess the intrapatient relation between levodopa PK-PD and SPECT measures of dopaminergic function in PD. Thirty-five PD patients, 1 to 4 on the Hoehn and Yahr (H&Y) scale, enrolled in the study. Each patient was examined by levodopa PK-PD modeling and SPECT imaging. Primary measure outcomes were the levodopa half-life in the effect compartment (t1/2(eq)) for PKPD modeling and the ratio of specific to non specific (SP/NSP) tracer striatal uptake for SPECT. Levodopa t1/2(eq) was highly significantly correlated with H&Y scale (r = -0.815, p < 0.0001), Unified Parkinson's disease Rating Scale (UPDRS) (r = -0.691, p < 0.0001) and PD symptom duration (r = -0.647, p < 0.0001). SPECT contralateral putamen SP/NSP ratio showed the most significant correlations with clinical indicators of disease severity: H&Y, r = -0.526, p < 0.002; UPDRS, r = -0.523, p < 0.002; symptom duration, r = -0.513, p < 0.002. Significant correlations were observed between levodopa t1/2(eq) and putamen SP/NSP ratios, yielding the closest correlation for the contralateral region (r = 0.522, p < 0.002). An indirect PK-PD dopaminergic functional variable and direct SPECT measures of presynaptic dopaminergic system homeostasis were in close agreement with clinical data and correlated to each other. Levodopa PK-PD modeling can be a practical clinical tool indirectly assessing the functional integrity of the nigrostriatal dopaminergic system in PD patients.
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PMID:Assessing dopaminergic function in Parkinson's disease: levodopa kinetic-dynamic modeling and SPECT. 1467 82

Functional imaging of the dopamine transporter (DAT) defines integrity of the dopaminergic system and has its main clinical application in patients with mild, incomplete, or uncertain parkinsonism. Imaging with specific single positron emission computerised tomography ligands for DAT (FP-CIT, beta-CIT, IPT, TRODAT) provides a marker for presynaptic neuronal degeneration. Striatal uptake correlates with disease severity, in particular bradykinesia and rigidity, and monitoring of progression assists in clinical trials of potential neuroprotective drugs. DAT imaging is abnormal in idiopathic Parkinson's disease, multiple system atrophy and progressive supranuclear palsy and does not distinguish between these disorders. Dopamine loss is seen even in the earliest clinical presentations of true parkinsonism; a normal scan suggests an alternative diagnosis such as essential tremor, vascular parkinsonism (unless there is focal basal ganglia infarction), drug-induced parkinsonism, or psychogenic parkinsonism. Congruence between working clinical diagnosis and DAT imaging increases over time in favour of baseline DAT imaging results. Additional applications are characterising dementia with parkinsonian features (abnormal results in dementia with Lewy bodies, normal in Alzheimer's disease); and differentiating juvenile-onset Parkinson's disease (abnormal DAT) from dopa-responsive dystonia (normal DAT).
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PMID:Role of dopamine transporter imaging in routine clinical practice. 1546

beta-CIT was labeled with 131I by the peracetic acid method. Cat model of Parkinsonism was set up with MPTP. Each of normal and PD model cats was given an injection of 74 MBq/0.5 ml 131I-beta-CIT into the femur vein. Then the blood samples were obtained at 4 h and 20 h, the radioactivity was counted with calibrator. The biodistribution data of 131I-beta-CIT in cat body was calculated (ID%/g). The cats were subjected to imaging at 0.5 h, 1 h, 2 h, 4 h, 20 h after the administration of radiopharmaceutical. The radioactivity in striatum and cerebellum was measured and striatal specific binding ratios were calculated. The Results showed that the radio chemical purity of 131I-beta-CIT was 97.62% +/- 0.31%. The 131I-beta-CIT remained stable for at least 4 h after incubation with water and serum respectively. Following intravenous administration in cats, 131I-beta-CIT showed high accumulation in striatum. The study of imaging in cats showed that striatal specific uptake of 131I-beta-CIT at 20 h after injection was 4.83 +/- 0.82 in normal cats and 2.92 +/- 0.66 in PD cats. There was a significant reduction of striatal tracer uptake in PD cats, compared to the controls. The results of biodistribution study was in agreement with the results of imaging study. These results suggest that beta-CIT is an ideal agent for dopamine transporter imaging and can be used for the diagnosis of Parkinson's disease.
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PMID:[Basic study of dopamine transporter imaging with 131I-beta-CIT]. 1471 69

Degeneration of substantia nigra has been described in spinocerebellar ataxia type 2 (SCA2). In this study, dopamine transporter (DAT) density with [123 I]FP-CIT SPECT was studied in six SCA2 patients with no parkinsonian signs, six Parkinson's disease (PD) patients, and six controls. Marked striatal DAT loss was found in both SCA2 and PD patients. However, a more severe reduction in the caudate and a higher putamen to caudate ratio distinguished SCA2 from PD patients, suggesting a more uniform nigrostriatal impairment in SCA2. Striatal DAT density of SCA2 patients correlated with the severity of cerebellar ataxia.
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PMID:Reduced striatal [123 I]FP-CIT binding in SCA2 patients without parkinsonism. 1499 22

A comparative study was carried out on two promising presynaptic dopamine transporter single-photon emission tomography (SPECT) radioligands with a fast pharmacokinetic profile, 123I-FP-beta-CIT (FP) and 99mTc-TRODAT-1 (TR), in order to assess their differential diagnostic power in early parkinsonism and their sensitivity for detection of disease progression. This cross-sectional study was conducted on 96 patients with early-stage parkinsonism referred in a tertiary clinical setting. Mean disease duration was 2.0+/-1.3 years, and patients had a modified Hoehn and Yahr (H&Y) stage of 1-2 (average 1.2). Forty-seven patients received TR, and 49 received FP. In both groups, ten patients with normal presynaptic function were included as a control population; all other patients were clinically diagnosed as having idiopathic Parkinson's disease. Groups were matched for gender, age, disease duration and modified H&Y stage. Triple-head gamma camera SPECT was analysed using a semiquantitative index of transporter binding (BI). Discriminant analysis with cross-validation resulted in a maximal classification accuracy for FP of 93% (sensitivity 95% and specificity 86%) for the contralateral putamen BI. For TR, the corresponding values were 87% accuracy, 92% sensitivity and 70% specificity. For FP, disease duration was correlated with both the putamen BI (-8.8%/year, rho=-0.41, P=0.025) and the putamen/caudate ratio (-7.4%/year, rho=-0.51, P=0.004), but for TR no significant correlation was found (all P values >0.5). In conclusion, both FP and TR show high sensitivity in a clinically relevant setting, but FP has superior accuracy for early differential diagnosis of idiopathic parkinsonism and non-degenerative extrapyramidal disorders, as well as better sensitivity for disease follow-up.
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PMID:Dopamine transporter SPECT using fast kinetic ligands: 123I-FP-beta-CIT versus 99mTc-TRODAT-1. 1506 72

After reports of reversible parkinsonism and cognitive impairment with sodium valproate (VPA), the authors examined 50 consecutive patients taking VPA and 20 patients taking carbamazepine. Three patients taking VPA exhibited unequivocal parkinsonism with Unified Parkinson Disease Rating Scale scores >30. VPA was withdrawn from two patients with improvement of symptoms. Reduction in VPA dosage in the third patient produced no improvement. beta-CIT-SPECT scans were normal, suggesting dopaminergic neuronal loss is not the underlying mechanism.
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PMID:Reversible parkinsonism with normal beta-CIT-SPECT in patients exposed to sodium valproate. 1511 93

Current medical and surgical therapies for Parkinson's disease provide symptomatic control of motor impairments rather than slowing or halting the progression of the disease. Previous clinical trials examining drugs such as dopamine agonists and selegiline for neuroprotective effects used "surrogate" outcomes, including clinical measures (rating scales, time to require levodopa), neuroimaging techniques (beta-CIT single photon emission computed tomography; fluorodopa positron emission tomography), and mortality tracking. These studies failed to provide conclusive results because of design faults such as failing to control for symptomatic effects, small sample size, and not accounting for the possible effects of drugs on radionuclide tracer handling. Lessons must be learned from these failed neuroprotection trials. This review summarises the problems with previous neuroprotection studies and makes recommendations for future trial design. It is concluded that the primary outcome of explanatory trials should continue to be clinical measures such as the Unified Parkinson's Disease Rating Scale (UPDRS). It should be assumed that all agents have a symptomatic effect, which necessitates evaluation after a prolonged drug washout period. To achieve the evaluation after a prolonged drug washout period more effectively, trials must be performed in early disease and over a short period (6-12 months) so that symptomatic therapy is not required. To achieve adequate statistical power, these trials will need to include thousands of patients. Radionuclide imaging can only be used in such trials after considerable methodological work has been performed to establish its validity and reliability. To be affordable, such large explanatory trials need more streamlined designs with fewer hospital visits, fewer outcome measures, and rationalised safety monitoring. The clinical effectiveness of promising compounds from explanatory trials will need to be established in large long-term pragmatic trials using outcome measures such as quality of life, cost-effectiveness, and mortality. Such pragmatic trials could be continuations of the explanatory trials: after the primary outcome of the explanatory study (e.g., UPDRS) has been reported in an interim analysis, the trial could be continued for a further 5 to 10 years to report on quality of life and health economics outcomes.
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PMID:A "cure" for Parkinson's disease: can neuroprotection be proven with current trial designs? 1513 11

Hereditary progressive dystonia with marked diurnal fluctuation/dopa-responsive dystonia (HPD/DRD) shows the considerable heterogeneity of clinical phenotypic expression and a dramatic sustained response to levodopa. The autosomal dominant HPD/DRD is caused by mutations in the gene coding GTP cyclohydrolase I (GCH I), the enzyme that catalyzes the first step in the biosynthesis of tetrahydrobiopterin. Previous studies suggested that normal [18F]Dopa positron emission tomography or [123I]beta-CIT single-photon emission computed tomography (SPECT) imaging, indicating intact structural integrity of nigrostriatal neurons, may be useful for differentiating HPD/DRD from clinically similar conditions such as juvenile Parkinson's disease with dystonia that have a considerably poorer prognosis. We here report a Korean family affected with HPD/DRD due to a novel missense mutation of the GCH I gene (T-->G mutation in exon 2), Met 137 Arg, which may change the conformation of the binding site of GCH I. The clinical features are considerably variable within the family. We documented normal striatal uptake of [123I]IPT, a dopamine transporter ligand with fast washout kinetics, in our patients by using SPECT. This method can be helpful in diagnosing HPD/DRD in uncertain cases.
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PMID:A novel missense mutation of the GTP cyclohydrolase I gene in a Korean family with hereditary progressive dystonia/dopa-responsive dystonia. 1516 67

The occurrence of parkinsonism in Alzheimer's disease (AD) is quite common, however the molecular and neurochemical changes underlying such extrapyramidal features in AD have been not fully understood. Post-mortem as well as in vivo imaging study have produced conflicting results as regards the existence of dopaminergic changes in AD. Aim of the present study was to investigate in vivo the nigro-striatal dopaminergic function in a group of AD patients with parkinsonism. Thirteen patients with AD and extrapyramidal features not related to past neuroleptic use (AD-P) underwent SPECT with 123I-FP-CIT, a ligand of dopamine transporter, and the data were compared with those obtained in 15 patients with Diffuse Lewy Body Dementia (DLBD), 20 patients with Parkinson's disease (PD), and 8 healthy elderly controls. The analysis of the data was performed by regions-of-interest approach and calculations of the striatal-to-non specific (occipital lobes) radioactivity ratios were made. The 123I-FP-CIT striatal uptake in patients with AD-P was similar to that obtained in the control population. Both the DLBD and PD groups showed significantly lower 123I-FP-CIT uptake in all striatal areas with respect to AD-P and control groups (p < 0.005). The lack of dopamine transporter changes in our series of AD-P patients can indicate that dopaminergic presynaptic function is preserved in this population and that different dopaminergic changes such as postsynaptic ones, or different neurotransmitter alterations might underlie the extrapyramidal features in AD.
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PMID:Presynaptic nigro-striatal function in a group of Alzheimer's disease patients with parkinsonism: evidence from a dopamine transporter imaging study. 1525 94


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