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)

Age-related human neurodegenerative diseases are a major social and medical problem. It is therefore logical to take into consideration every theory with an overall approach to neurodegenerative diseases. This environmental proposal relies mainly on data concerning the Western Pacific amyotrophic lateral sclerosis-Parkinsonism-dementia complex (WP ALS-PD) considered as 'a prototypal human neurodegenerative disease' and on extrapolation from it to the bulk of neurodegenerative diseases (NDD). NDD would be due to an accelerated ageing process in certain populations of neurons due to the noxious synergy of (1) increased environmental slow deleterious factors (such as slow toxins) and of (2) decreased environmental protective factors (Mg deficient intake particularly). First, it was observed that three apparently dissimilar conditions occurred at extraordinary high rates in the Guam area: motoneuron disease (ALS), Parkinson's disease (P) and Alzheimer's-like dementia (D). Next, several other foci of endemic ALS-PD were found in Asia and Oceania in three Western Pacific population groups. These included the Chamorro people in Mariana Islands (Guam and Rota), the Auyu and Jakai people of West New Guinea and the Japanese residents of the Kii peninsula (Honshu island). The post-Second World War decline of the occurrence of WP ALS-PD in all three high incidence disease foci coupled with the absence of demonstrable heritable or transmissible factors had led to focus the search for the cause of this degenerative disease on nontransmissible environmental factors that are disappearing as the susceptible population groups acculturate to modern way. Epidemiologic study has shown that preference for traditional Chamorro food is the only one of 23 tested variables significantly associated with an increased risk for PD. An early suggestion incriminated the toxic seed of the false sago palm (Cycas circinalis L) which was used in traditional food and medicine. Laboratory investigation of cycad seed revealed the presence of various toxins and particularly of an 'unusual' non protein aminoacid: L-BMAA (beta-N-methylamino-L-alanine), an excitotoxic aminoacid. This slow toxin presents some structural similarity to another 'unusual' excitotoxic aminoacid: L-BOAA (beta-N-oxalyl-amino-L-alanine), an exogenous neurotoxin present in the grass pea (Lathyrus sativus) whose excessive consumption may cause lathyrism. The excitotoxicity of both L-BMAA and L-BOAA mainly concerns non-NMDA receptors. The neurotoxicity of these aminoacids varies with experimental models failing to induce an experimental model akin to WP ALS-PD or displaying many of the motor-system and behavioral changes of WP ALS-PD. It may be due to the presence of physiological levels of bicarbonate or of various toxic cofactors: bio-organic such as cycasin or inorganic such as pollutant metals e.g. aluminum or manganese, together with the lack of protective factors (e.g. calcium and magnesium deficiencies). Combined Al intoxication with Ca-Mg deficiencies is a reasonable model to investigate the pathogenesis of neurodegenerative diseases and eventually to screen their treatments. It may also be considered as a model of magnesium deficit, but it does not concern simple magnesium deficiency reversible with mere oral physiological magnesium supplementation. Magnesium deficiency cannot result in neurodegenerative disease. Combined Al intoxication with Ca-Mg deficiencies is not reversible through physiological oral magnesium supplementation. It therefore constitutes a type of experimental magnesium depletion model, instrumental in the investigation of the pathogenesis of magnesium depletion and in the screening of its still unknown possible treatments. (ABSTRACT TRUNCATED)
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PMID:Are age-related neurodegenerative diseases linked with various types of magnesium depletion? 951 30

The mechanism of pathogenesis of idiopathic Parkinson's disease (PD) is unknown. In a study of 200 PD patients and 200 age- and sex-matched controls, Strang noted a marked and statistically significant higher incidence of ulcers (diagnosed by X-ray or surgery) in the PD patients compared to the controls (14% to 4%). These results have been discussed but never explained. Studies have shown increased concentrations of aluminum in the substantia nigra of PD patients compared to controls. Aluminum is thought to be a cellular toxin. Here I suggest that aluminum, and in particular aluminum-containing antacids may contribute to the pathogenesis of idiopathic PD.
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PMID:Aluminum-containing antacids as a cause of idiopathic Parkinson's disease. 1049 20

Occupational exposure to specific metals (manganese, copper, lead, iron, mercury, zinc, aluminum and others) appears to be a risk factor for Parkinson's disease (PD) in some, but not all, case-control studies. These epidemiological studies are reviewed. Several methodological issues that may account for the lack of unanimity of findings are discussed, and suggestions for improved case-control methodology are offered. The study of the neurological disease outcome of workers who have had long-term, well-defined occupational exposure to one or more metals is also urged, with collaborative work including industrial hygienists, occupational toxicologists, neurologists, epidemiologists and biostatisticians. Such efforts, employing state-of-the-art case and control ascertainment and enrollment from suitable population bases, neurological diagnostic rigor and exposure assessment, will help to further define the potentially important roles played by metals in PD and other neurodegenerative disorders.
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PMID:Occupational metal exposures and the risk of Parkinson's disease. 1054 82

Monoamine oxidase type B (MAO-B) activity is elevated in certain neurological diseases such as Alzheimer's and Parkinson's disease with respect to age-matched controls; the cause of this elevation is unknown. The documented accumulation of aluminum in certain neurodegenerative diseases prompted us to test the effect of Al3+ on the activity of MAO-B in rat brain homogenate. Results showed that the metal ion significantly increased MAO-B enzymatic activity in a dose-dependent manner, yielding a K(M) of 5.69 microM compared with 34.45 microM in the absence of the metal ion. The Vmax of 45.34 micromol/min was unchanged in the presence of the metal ion.
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PMID:Activation of monoamine oxidase type-B by aluminum in rat brain homogenate. 1061 59

Motor fluctuations and abnormal involuntary movements are common complications encountered in advanced Parkinson's disease (PD) patients with long-term levodopa therapy. Monitoring of plasma levodopa concentrations and clinical effects has been reported to benefit the management of these complications. However, to our knowledge, there is no data available in Taiwan concerning the correlation between the plasma levodopa levels and motor fluctuations. In this study, we developed the laboratory methodology for plasma levodopa determination by using the aluminum extraction procedure and HPLC-ED. Serial blood samples and motor scores were obtained from 7 PD patients, and the correlation between plasma levodopa levels and motor responses were studied individually. In three patients with wearing-off phenomenon, plasma levodopa concentrations are compatible with the clinical "on" and "off" states. In the other four patients with complex fluctuating responses, their levodopa dosages were adjusted by the results of monitoring. Better motor responses were achieved by optimization of the levodopa pharmacokinetics in these patients. Our preliminary data suggest that simultaneous monitoring of plasma levodopa concentrations and clinical effects might be helpful to improve the therapeutic strategy in some of the parkinsonian patients with fluctuating responses to levodopa.
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PMID:Monitoring of the levodopa concentration-response relationship in Parkinson's disease. 1084 47

In a previous paper, it was suggested that a relative deficiency of essential fatty acids might play a role in the etiology of sporadic or non-familial Alzheimer's disease. A recent article regarding dementia in the Rotterdam Study reinforces this suggestion. It is also hypothesized that this relative deficiency could facilitate passage of aluminum into the brain, aluminum being increasingly suggested as one of the possible pathogenic factors in AD. It is further suggested that hypomethylation caused by a deficiency of S-adenosylmethionine might also play a role in the etiology of this disease and perhaps even of Parkinson's disease.
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PMID:Alzheimer's disease revisited. 1085 85

Parkinson's disease involves the aggregation of alpha-synuclein to form fibrils, which are the major constituent of intracellular protein inclusions (Lewy bodies and Lewy neurites) in dopaminergic neurons of the substantia nigra. Occupational exposure to specific metals, especially manganese, copper, lead, iron, mercury, zinc, aluminum, appears to be a risk factor for Parkinson's disease based on epidemiological studies. Elevated levels of several of these metals have also been reported in the substantia nigra of Parkinson's disease subjects. We examined the effect of various metals on the kinetics of fibrillation of recombinant alpha-synuclein and in inducing conformational changes, as monitored by biophysical techniques. Several di- and trivalent metal ions caused significant accelerations in the rate of alpha-synuclein fibril formation. Aluminum was the most effective, along with copper(II), iron(III), cobalt(III), and manganese(II). The effectiveness correlated with increasing ion charge density. A correlation was noted between efficiency in stimulating fibrillation and inducing a conformational change, ascribed to formation of a partially folded intermediate. The potential for ligand bridging by polyvalent metal ions is proposed to be an important factor in the metal-induced conformational changes of alpha-synuclein. The results indicate that low concentrations of some metals can directly induce alpha-synuclein fibril formation.
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PMID:Metal-triggered structural transformations, aggregation, and fibrillation of human alpha-synuclein. A possible molecular NK between Parkinson's disease and heavy metal exposure. 1155 18

Several metals have toxic actions on nerve cells and neurobehavorial functioning. These toxic actions can be expressed either as developmental effects or as an increased risk of neurodegenerative diseases in old age. The major metals causing neurobehavioral effects after developmental exposure are lead and methylmercury. Lead exposure in young children results in a permanent loss of IQ of approximately 5 to 7 IQ points, and also results in a shortened attention span and expression of anti-social behaviors. There is a critical time period (<2 years of age) for development of these effects, after which the effects do not appear to be reversible even if blood lead levels are lowered with chelation. Methylmercury has also been found to have effects on cognition at low doses, and prenatal exposure at higher levels can disrupt brain development. Metals have also been implicated in neurodegenerative diseases, although it is unlikely that they are the sole cause for any of them. Elevated aluminum levels in blood, usually resulting from kidney dialysis at home with well water containing high aluminum, result in dementia that is similar to but probably different from that of Alzheimer's disease. However, there is some epidemiological evidence for elevated risk of Alzheimer's in areas where there is high concentration of aluminum in drinking water. Other metals, especially lead, mercury, manganese and copper, have been implicated in amvotrophic lateral sclerosis and Parkinson's disease.
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PMID:Effects of metals on the nervous system of humans and animals. 1176 47

Aluminum is a well known neurotoxic agent that is overaccumulated in the substantia nigra of patients affected by Parkinson's disease as well as in certain cerebral areas of other neurodegenerative pathologies such as Alzheimer's disease. Although the role of aluminum in neurodegenerative diseases is yet to be clearly understood, the metal ion is known to substantially alter the activity of several key enzymes in the central nervous system. The present paper reports data on the effect of aluminum on the activity of dopamine-beta-hydroxylase from bovine adrenaL gland utiLized as a model study. The metal ion inhibited the activity of this enzyme with a mixed type mechanism following the Michaelis-Menten equation. In the absence of Al, the enzyme exhibited a Km and Vmax of 2.56 mM of 4.12 pmol/min respectively, while in the presence of Al its Km and Vmax were 3.85 mM and 2.86 pmol/min respectively. The potential implications of aluminum in the etiopathogenesis of neurological disorders are discussed.
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PMID:Inhibitory effect of aluminum on dopamine beta-hydroxylase from bovine adrenal gland. 1178 79

Aluminum and zinc have been related to the pathogenesis of Parkinson's disease (PD), the former for its neurotoxicity and the latter for its apparent antioxidant properties. 6-Hydroxydopamine (6-OHDA) is an important neurotoxin putatively involved in the pathogenesis of PD, its neurotoxicity often being related to oxidative stress. The potential effect of these metals on the oxidative stress induced by 6-OHDA autoxidation and the potential of ascorbic acid (AA), cysteine, and glutathione to modify this effect were investigated. Both metals, particularly Al3+, induced a significant reduction in *OH production by 6-OHDA autoxidation. The combined action of AA and a metal caused a significant and sustained increase in *OH generation, particularly with Al3+, while the effect of sulfhydryl reductants was limited to only the first few minutes of the reaction. However, both Al3+ and Zn2+ provoked a decrease in the lipid peroxidation induced by 6-OHDA autoxidation using mitochondrial preparations from rat brain, assessed by TBARS formation. In the presence of AA, only Al3+ induced a significant reduction in lipid peroxidation. After intrastriatal injections of 6-OHDA in rats, tyrosine hydroxylase immunohistochemistry revealed that Al3+ reduces 6-OHDA-induced dopaminergic lesion in the striatum, which corroborates the involvement of lipid peroxidation in 6-OHDA neurotoxicity and appears to discard the participation of this mechanism on PD by Al3+ accumulation. The previously reported antioxidant properties of Zn2+ appear to be related to the induction of Zn2+-containing proteins and not to the metal per se.
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PMID:Effects of aluminum and zinc on the oxidative stress caused by 6-hydroxydopamine autoxidation: relevance for the pathogenesis of Parkinson's disease. 1195 57


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