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)

The cause of Parkinson's Disease remains unknown although environmental toxin/s and ageing are likely to play a significant role. Experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced parkinsonism can be prevented by monoamine oxidase B inhibitors. Monoamine oxidase B inhibitors have been shown to delay disease progression in early Parkinson's Disease and improve mortality. Symptomatic therapy remains the cornerstone of drug treatment, and should include levodopa replacement with concomitant dopamine agonist therapy in order to achieve maximum efficacy, and reduce side effects. Complicated Parkinson's Disease could be managed by better delivery systems like slow release preparations and parenteral infusions. Brain tissue transplants may offer hope of restoring the damaged nigrostriatal system.
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PMID:Drug treatment of Parkinson's disease: current concepts. 202 54

Monoamine oxidase B (MAO B) plays a pivotal role in N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced Parkinsonism. An increased MAO B activity in platelets of patients with idiopathic Parkinson's disease (PD) is reported in this study. The possibility that high MAO B activity may represent a trait of vulnerability for PD by enhancing the neurotoxic effects of environmental compounds is discussed.
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PMID:Platelet monoamine oxidase B activity in parkinsonian patients. 226 65

Monoamine oxidase B (MAO-B) is implicated in the cause of Parkinson's disease (PD) because of its role in metabolizing the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and forming H2O2 during dopamine metabolism. Altered MAO-B activity has been observed in PD platelets. Polymerase chain reaction was used to amplify a portion of the MAO-B gene. Polymerase chain reaction products were screened with restriction enzymes to identify fragments useful for single-stranded conformational polymorphism analysis. A single-stranded conformational polymorphism was identified in an MAO-B polymerase chain reaction product after Hae III digestion. One hundred twenty-one control individuals were allelotyped with frequencies of 0.45 and 0.55 for alleles 1 and 2, respectively. Frequencies of 0.62 and 0.38 (1 and 2, respectively) were observed in a population of 46 patients with PD. The presence of MAO-B allele 1 is associated with a relative risk for PD of 2.03-fold (confidence interval, 1.44-2.61; p < 0.02). For comparison, a monoamine oxidase A polymorphism was used to determine allelic frequencies in these same populations and no statistically significant differences were found. These results suggest that an inherited variant of MAO-B may be involved in a genetic predisposition for PD.
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PMID:Association of a monoamine oxidase B allele with Parkinson's disease. 848 7

Monoamine oxidase B (MAO-B) is an enzyme that has relevance for Parkinson disease (PD) because of its roles in catabolizing dopamine and potentially activating exogenous neurotoxicants. A polymorphism of the gene encoding MAO-B has been identified as a single base change (A or G) in intron 13 of the X chromosome. The A allele was previously associated with an approximately twofold risk of PD. The present study compared A and G allele frequencies between newly diagnosed idiopathic PD cases and a control group free of neurodegenerative diseases. All study subjects were Caucasian. Cases were 37 men and 25 women, age 37-80 years; controls were 50 men and 29 women, age 45-82 years. MAO-B genotype was determined by the allele-specific polymerase chain reaction on DNA extracted from peripheral lymphocytes. In complete contrast to previous studies, elevated risks were detected with the G allele. The age-adjusted odds ratio for the G allele in males was 1.87 ((95% confidence interval) 0.78-4.47). Among females the age-adjusted odds ratios were 5.00 ((95% confidence interval) 1.13-22.1) for the GA genotype and 5.60 ((95% confidence interval) 1.01-30.9) for the GG genotype. These findings, although of limited statistical precision, suggest that the G allele of this MAO-B polymorphism may relate to PD risk.
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PMID:Association of a polymorphism in intron 13 of the monoamine oxidase B gene with Parkinson disease. 912 14

The effect of selegiline (L-deprenyl) on plasma catecholamines, clinical response, and drug tolerability was studied in 13 patients with Parkinson's disease (PD) treated with L-Dopa/benserazide and entacapone, a peripheral catechol-O-methyltransferase (COMT) inhibitor, in a placebo-controlled double-blind study. An L-Dopa test was performed on 3 study days. The first study day was with L-Dopa/benserazide only (control), the second after 14 days of treatment with 200 mg entacapone taken concomitantly with L-Dopa/benserazide in combination with either selegiline (10 mg daily) or placebo. After a 2-week washout period, selegiline and placebo treatments were switched, and the third study day was after 14 days of treatment. During the study days, clinical response was evaluated at 30-min intervals for 6 h, by using the motor score of the Unified Parkinson's Disease Rating Scale (UPDRS). In addition, repeated blood pressure measurements were made, and plasma samples were taken for analysis of L-Dopa, 3-O-methyldopa (3-OMD), dihydroxyphenyl acetic acid (DOPAC), homovanillic acid (HVA), dopamine, noradrenaline, and 3-methoxy-4-hydroxyphenylethylene glycol (MHPG). Monoamine oxidase B (MAO-B) and COMT enzyme activities were measured from platelets and erythrocytes, respectively. Entacapone improved the clinical response to L-Dopa during both selegiline and placebo (p < 0.001) treatments. The improvement was more marked during combined selegiline and entacapone treatment than with entacapone alone (p < 0.01). Entacapone significantly increased plasma L-Dopa and DOPAC levels and decreased plasma 3-OMD and MHPG levels both with selegiline and placebo. Selegiline partially inhibited the entacapone-induced increase of plasma DOPAC. Plasma dopamine and noradrenaline levels did not change. Entacapone decreased erythrocyte COMT activity by > 35% (p < 0.001), and platelet MAO-B activity was almost completely inhibited by selegiline (p < 0.001). One patient withdrew because of diarrhea, dizziness, and loss of sleep when receiving selegiline treatment. Otherwise no differences in adverse events, mean daily blood pressures, or other safety parameters were observed between selegiline and placebo treatments. Our results suggest that entacapone can be safely administered together with L-Dopa and selegiline in patients with PD, although further studies with larger number of patients and longer treatment periods are necessary to confirm this finding.
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PMID:Simultaneous MAO-B and COMT inhibition in L-Dopa-treated patients with Parkinson's disease. 925 Oct 66

Monoamine oxidase B (MAOB) metabolises dopamine and activates neurotoxins known to induce parkinsonism in humans and primates. Therefore the MAOB gene (MAOB; Xp15.21-4) is a candidate gene for Parkinson's disease (PD). Longer length dinucleotide repeat sequences in a highly polymorphic GT repeat region of intron 2 of this gene showed an association with PD in an Australian cohort. We repeated this allele-association study in a population of 176 Chinese PD patients (90 men, 86 women) and 203 agematched controls (99 men, 104 women). Genomic DNA was extracted from venous blood and the polymerase chain reaction was used to amplify the appropriate regions of the MAOB gene. The length of each (GT) repeat sequence was determined by 5% polyacrylamide denaturing gel electrophoresis. There was no significant difference in allele frequencies of the (GT) repeat allelic variation between patients and controls (chi2 = 2.48; df = 5, P<0.75). Therefore the longer length GT repeat alleles are not associated with PD in this Chinese population. Possible reasons for the discrepancy between Chinese and Australian populations include a different interaction between this genetic factor and environmental factors in the two populations and the possibility that the long length GT repeat alleles may represent a marker mutation, genetically linked to another susceptibility allele in whites but not in Chinese. Methodological differences in the ascertainment of cases and controls in this cohort could also explain the observed differences. Further study is required to determine whether the longer length GT repeat alleles are true susceptibility alleles in PD.
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PMID:The monoamine oxidase B gene GT repeat polymorphism and Parkinson's disease in a Chinese population. 1070 98

The purpose of the new drugs for Parkinson's disease is control of the long-term levodopa treatment syndromes, especially wearing-off phenomenon and dyskinesia. Therefore, they show long T1/2. Most of them are classified into dopamine agonists. Others are monoamine oxidase B inhibitor and cathecole-o-methyltransferase inhibitor. Marketed dopamine agonists are bromocriptine, pergolide, talipexole, and cabergoline in Japan. Except talipexole, they are all ergot alkaloid derivatives. Their affinity for dopamine receptor is D2 group, and their T1/2 are longer than levodopa. Bromocriptine is an oldest dopamine agonist. Other 3 drugs and bromocriptine had made each other double blinded cross over trial previously. The result of double blinded studies show that their efficacy for PD treatment were equal, 40-50% patients with PD. However, in clinical usage, some difference is observed as described below. Efficacy of pergolide is strong compared with bromocriptine; however, pergolide is easy to arise dyskinesia. Talipexole is strong in the hypnosis effect. As for cabergoline, it takes long time to show medical effect, so that it is expected to control wearing-off phenomenon. Monoamine oxidase B inhibitor, Selegiline, is useful as an economizer effect to levodopa. As for the cathechole-o-methyltransferase inhibitor (COMT-I) will be make double-blinded trial in future. The efficacy for PD treatment of COMT-I is prolonged levodopa effect for PD, so that wearing-off phenomenon will be controlled. To use these drugs successfully is important with the treatment of PD. In the future, the development of the cause therapy in addition to the systematic therapy is wanted.
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PMID:[The new Parkinson's disease drugs]. 1106 48

Monoamine oxidase B (MAO-B) inhibitors are potentially useful in the therapeutic treatment of Parkinson's disease. L-Deprenyl has been shown to slow nigrostriatal tract degeneration in human idiopathic Parkinsonism and to be an effective neuroprotector in experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity models. However, L-amphetamine and (-)methamphetamine, the metabolites generated by L-deprenyl, can have adverse and severe side-effects. Therefore, the search for new MAO-B inhibitors without potential amphetamine-like properties is a matter of great therapeutic interest. The present report is the first to describe the neuroprotective effect--following chronic intraperitoneal (i.p.) treatment--of a novel and non-amphetaminic MAO-B inhibitor, [N-(2-propynyl)-2-(5-benzyloxy-indolyl) methylamine] (PF 9601N), on the neurodegeneration of nigral dopaminergic neurons caused by administration of intrastriatal 6-hydroxydopamine (6-OHDA). Two groups of six animals were unilaterally injected with 6-OHDA in the right striatum. One group was treated daily with 60 mg/kg PF 9601N i.p., starting before stereotaxic lesion and continuing for 18 days thereafter. The other group was treated with vehicle solution. Coronal slabs including the substantia nigra pars compacta (SNpc) were processed for tyrosine hydroxylase immunohistochemistry (TH). The number of TH positive (TH+) neurons in the SNpc was 60% lower in 6-OHDA lesioned rats. However, the loss of TH+ neurons in the SNpc was only 30% in PF 9601N i.p.-treated animals. Therefore, treatment with the specific MAO-B inhibitor significantly reduced the 6-OHDA-induced degeneration to about 50%.
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PMID:Neuroprotective effect of the monoamine oxidase inhibitor PF 9601N [N-(2-propynyl)-2-(5-benzyloxy-indolyl) methylamine] on rat nigral neurons after 6-hydroxydopamine-striatal lesion. 1216 3

There is increasing evidence to challenge the traditional view that the initiation of drug treatment in Parkinson's disease (PD) should be delayed until the patient has significant disability such as to affect work or social function. Firstly, to delay treatment sentences the patient to protracted impairment of quality of life that could be improved by therapy. Secondly, there is evidence to support the notion that earlier rather than later initiation of treatment leads to better long term motor benefit. The selection of which drug to begin must be tailored to the patient's individual characteristics and circumstances. Monoamine oxidase B inhibitors result in a mild improvement in motor function compared to dopamine agonists or levodopa. They are well tolerated, easy to use once a day drugs and there is evidence that early use of Rasagiline improves motor outcome. Dopamine agonists lead to a substantial improvement in motor function and are, or will shortly be, available as once a day drugs. They are generally well tolerated but can be associated with exacerbating confusion or hallucinations and with behavioral changes. Levodopa is the most potent of the dopaminergic drugs. It is routinely combined with a dopa decarboxylase inhibitor and can also be used with a catecholo-o-methyl transferase inhibitor for enhanced absorption. The most important limiting factor for the use of levodopa is the emergence of motor complications. These are related to a number of factors including the dose of levodopa and the duration of its use.
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PMID:Drug selection and timing of initiation of treatment in early Parkinson's disease. 1939 73

The ADAGIO study demonstrated a symptomatic benefit for rasagiline in early Parkinson's disease (PD) and suggested a disease-modifying effect. Evidence indicates that mitochondrial dysfunction plays a role in the pathogenesis of PD and that this may be the site of effect for rasagiline. In this systematic review, evidence for the role of mitochondria in the pathogenesis of PD are reviewed in light of other proposed mechanisms of neuronal degeneration and the actions of rasagiline and its component parts, namely propargylamine and the metabolite, aminoindan. Evidence for the role of mitochondria in the pathogenesis and treatment of PD are reviewed in light of other proposed mechanisms of neuronal degeneration and clinical actions of rasagiline. Monoamine oxidase B (MAO-B) located in the outer mitochondrial membrane controls dopamine metabolism in early PD, and this is the likely location for the symptomatic action of rasagiline. Accumulating evidence indicates that mitochondrial impairment contributes to dopaminergic neuronal loss in PD, either directly or through other mechanisms such as oxidative stress or protein misfolding. Further rasagiline affects numerous mitochondrial mechanisms that prevent apoptotic cell death including prevention of opening of the mitochondrial transition pore, decreased release of cytochrome C, alterations in pro-antiapoptotic genes and proteins, and the nuclear translocation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Thus, the functional neuroprotective actions of rasagiline may not be dependent on MAO-B inhibition, but rather may involve actions of the propargylamine moiety and the aminoindan metabolite. An accumulating body of literature indicates a mitochondrial site of action for rasagiline and highlights the neuroprotective action of the drug, providing strong biological plausibility for disease-modifying effects of the drug such as those observed in ADAGIO.
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PMID:Explaining ADAGIO: a critical review of the biological basis for the clinical effects of rasagiline. 2195 31


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