Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidation of the catecholaminergic neurotransmitter dopamine (1) at physiological pH normally results in formation of black, insoluble melanin polymer. In this study, it is demonstrated that L-cysteine (CySH) can divert the melanin pathway by scavenging the proximate o-quinone oxidation product of 1 to give 5-S-cysteinyldopamine (8). This cysteinyl conjugate is further oxidized in the presence of free CySH to give 7-(2-aminoethyl)-3,4-dihydro-5-hydroxy-2H- 1,4-benzothiazine-3-carboxylic acid (11) and its 6-S-cysteinyl (12), 8-S-cysteinyl (14), and 6,8-di-S-cysteinyl (16) conjugates in addition to many other unidentified compounds. 5-S-Cysteinyldopamine (8) and dihydrobenzothiazines 11, 12, 14, and 16 are all more easily oxidized than 1. With increasing molar excesses of CySH, the formation of melanin is decreased and, ultimately, completely blocked. Preliminary experiments have revealed that when injected into the brains of laboratory mice, dihydrobenzothiazine 11 and its cysteinyl conjugates 12 and 14 are lethal and evoke profound behavioral responses including hyperactivity and tremor. On the basis of these results and other recent observations, a new hypothesis has been advanced which might help explain the selective degeneration of nigrostriatal dopaminergic neurons which occurs in idiopathic Parkinson's Disease (PD). This hypothesis proposes that in response to some form of chronic brain insult, the activity of gamma-glutamyltranspeptidase is upregulated leading to an increased rate of translocation of glutathione (GSH) into the cytoplasm of dopaminergic cell bodies in the substantia nigra (SN) para compacta. The results of this in vitro study predict that such an elevated translocation of GSH into heavily pigmented dopaminergic neurons would cause a diversion of the neuromelanin pathway with consequent depigmentation of these cells and formation of 8, all of which occur in the Parkinsonian SN. The further very facile oxidation of 8 which must occur under intraneuronal conditions where 1 is autoxidized, i.e., in neuromelanin-pigmented cells, would lead to dihydrobenzothiazine 11 and its cysteinyl conjugates which could be the endotoxins responsible for the selective degeneration of dopaminergic SN neurons in PD. The ease of autoxidation of 8 is suggested to account for the low levels of this conjugate found in the degenerating and Parkinsonian SN.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of L-cysteine on the oxidation chemistry of dopamine: new reaction pathways of potential relevance to idiopathic Parkinson's disease. 790 37

It was noticed that monotonous diet which imitated the composition of diet for the susceptible population of Keshan disease with a habit of food preference was prominently low in calcium and selenium. The plasma calcium ion content of rats kept on a monotonous diet was significantly lowered to merely half the content of the stock diet group with significant lowering of GSH-px activity. After peritoneal injection of furosemide, the plasma calcium ion contents of the monotonous diet group were further lowered significantly and signs of calcium deficiency, such as muscle tremor, spasm and convulsion might occur. If anoxic factor NaNO2 acted simultaneously, acute and severe myocardial necrosis developed. Morphologically, the myocardial necrosis was similar to that in Keshan disease. When monotonous diet was supplemented with only calcium, the growth state of the rats was significantly improved, and the degree of myocardial necrosis was significantly decreased. Supplement of calcium, selenium as well as vitamin E, seemed more effective. It is suggested that low selenium is the basic factor of endemic pathogenesis of Keshan disease, and low calcium intake by food preference among the susceptible population of Keshan disease plays an important role in the pathogenesis of myocardial necrosis in Keshan disease.
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PMID:[Effects of low calcium on myocardial necrosis of Keshan disease by food preference]. 822 83

The initial step in the genesis of neuromelanin, a black polymeric pigment normally found in the cytoplasm of dopaminergic cell bodies in the substantia nigra (SN), is the autoxidation of dopamine (DA) to DA-o-quinone (1). In this investigation, it is demonstrated that in the presence of L-cysteine (CySH) o-quinone 1 is scavenged to give 5-S-cysteinyldopamine (5-S-Cys-DA, major product) and 2-S-cysteinyldopamine (2-S-CyS-DA, minor product). These cysteinyl conjugates are more easily oxidized than DA. The relative yields of the resulting products are dependent on the concentration of free CySH. These products include 2,5-bi-S-cysteinyldopamine (2,5-bi-S-CyS-DA) and 2,5,6-tri-S-cysteinyldopamine (2,5,6-tri-S-CyS-DA), 7-(2-aminoethyl)-3,4-dihydro-5-hydroxy-2H-1,4-benzothiazine-3-carboxylic acid (DHBT-1), 8-(2-aminoethyl)-3,4-dihydro-5-hydroxy-2H-1,4-benzothiazine-3-carboxylic acid (DHBT-5), and a number of cysteinyl conjugates of these dihydrobenzothiazines (DHBTs). 2,5-Bi-S-CyS-DA, DHBT-1, the 6-S-cysteinyl conjugate of DHBT-1, DHBT-5, and the 6-S-cysteinyl conjugate of DHBT-5 were lethal when administered into the brains of laboratory mice and evoke a very characteristic hyperactivity syndrome and episodes of severe tremor. These and related results provide support for the hypothesis that the massive, irreversible loss of glutathione (GSH), increased 5-S-CyS-DA/DA concentration ratio, and depigmentation of dopaminergic neurons in the SN that all occur in Parkinson's disease (PD) might be caused by the gamma-glutamyl transpeptidase-mediated translocation of CySH (and/or GSH) into these cells. Furthermore, the resulting cysteinyldopamines and DHBTs might include endotoxic metabolites responsible for the selective degeneration of nigrostriatal dopaminergic neurons and PD.
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PMID:Further insights into the influence of L-cysteine on the oxidation chemistry of dopamine: reaction pathways of potential relevance to Parkinson's disease. 883 20

Ethanol is metabolized in the brain by catalase/H2O2 to yield acetaldehyde and by an ethanol-inducible form of cytochrome P450 (P450 IIE1) in a reaction that yields oxygen radicals. Within the cytoplasm of serotonergic axon terminals these metabolic pathways together provide conditions for the endogenous synthesis of 1-methyl-6-hydroxy-1,2,3,4-tetrahydro-beta-carboline (1), by reaction of acetaldehyde with unbound 5-hydroxytryptamine (5-HT), and for the oxygen radical-mediated oxidation of this alkaloid. The major initial product of the hydroxyl radical (HO.)-mediated oxidation of 1 in the presence of free glutathione (GSH), a constituent of nerve terminals and axons, is 8-S-glutathionyl-1-methyl-1,2,3,4-tetrahydro-beta-carboline-5,6-dione (6). When administered into the brains of mice, 6 is a potent toxin (LD50 = 2.9 microg) and evokes episodes of hyperactivity and tremor. Compound 6 binds at the GABA(B) receptor and evokes elevated release and turnover of several neurotransmitters. Furthermore, the GABA(B) receptor antagonist phaclofen attenuates the behavioral response caused by intracerebral administration of 6. These observations suggest that 6 might be an inverse agonist at the GABA(B) receptor site. Accordingly, it is speculated that ethanol drinking might potentiate formation of 6 that contributes to elevated release of several neurotransmitters including dopamine (DA) and endogenous opioids in regions of the brain innervated by serotonergic axon terminals. Subsequent interactions of DA and opioids with their receptors might be related to the initial development of dependence on ethanol. Redox cycling of 6 (and of several putative secondary metabolites) in the presence of intraneuronal antioxidants and molecular oxygen to produce elevated fluxes of cytotoxic reduced oxygen species might contribute to the degeneration of serotonergic pathways. Low levels of 5-HT in certain brain regions of the rat predisposes these animals to drink or augments drinking. Accordingly, 6, formed as a result of ethanol metabolism in the cytoplasm of certain serotonergic axon terminals, might contribute to the initial development of dependence on ethanol, by mediating DA and opioid release, and long-term preference and addiction to the fluid as a result of the progressive degeneration of these neurons.
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PMID:Putative oxidative metabolites of 1-methyl-6-hydroxy-1,2,3,4-tetrahydro-beta-carboline of potential relevance to the addictive and neurodegenerative consequences of ethanol abuse. 916 Jul 98

We examined the maintenance of functional and morphological integrity of precision-cut rat liver slices cultured in various incubation systems and conditions for 72 h. Slices were incubated (37 degrees C) for 6, 24, 48, and 72 h in supplemented Williams E medium in 6-well plastic culture plates on a gyratory shaking platform (WPCS) or in a rotating organ culture system (ROCS) using 5% CO2--95% air (WPCS/air or ROCS/air) or 5% CO2--70% O2--25% N2 (WPCS/O2 or ROCS/O2). Biochemical and functional parameters of slices maintained in WPCS/air or WPCS/O2 were almost totally inhibited after 24 h, in keeping with the extensive and diffuse coalescing coagulative necrosis typical of post-ischemic injury affecting almost all the slice surface after 48 h. As compared to freshly isolated slices, slices maintained in ROCS/air for 72 h showed stable ATP and GSH content, increased protein synthesis, and a slight steady decrease in GST activity, while ATP and GST activity remained stable and protein synthesis and GSH content increased in slices incubated in ROCS/O2 for 72 h. The extent of coagulative necrosis was markedly lower in longitudinal sections from slices incubated for 72 h in ROCS/O2 than in ROCS/air. Transversal sections from slices kept in ROCS/air for 72 h showed a thick central band of necrotic cells edged by two peripheral layers of viable hepatocytes, whereas most of the slice was composed of viable hepatocytes lined by two thin layers of necrotic cells after 72 h in ROCS/O2. ROCS/O2 emerged as the system best preserving the histological and functional integrity of rat liver slices in long-term culture.
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PMID:Morphological and functional integrity of precision-cut rat liver slices in rotating organ culture and multiwell plate culture: effects of oxygen tension. 968 91

The effects of pH, broth volume, initial sugar concentration, ratio of carbon to nitrogen and phosphorus, and the glucose feeding method on GSH production in a shaking flask were investigated. The results showed that the proper pH and broth content for GSH production were 6.0 and 60 ml broth per 500 ml flask, respectively. The initial glucose concentration distinctly affected the GSH production; the intracellular GSH content of yeast would decrease when the initial glucose concentration was beyond 12 g/L. A glucose feeding strategy with the purpose of controlling the specific growth rate at an expected value was developed and applied to a 12 hour fermentation with the total glucose concentration 26.2 g/L; the final cell concentration (DCW) and the intracellular GSH content could reach 8.78 g/L and 13.6 mg/g, respectively, while the total GSH in the broth was 119.4 mg/L and the yield of cell to glucose was 0.335 g/g.
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PMID:The effect of environmental conditions and glucose feeding in shaking flask on glutathione (GSH) production. 1019 32

Glutathione peroxidase (GSH-Px), from commercial bovine erythrocytes or ammonium sulfate fractionations (30-45%, 45-60%, 60-75% and 75-90% saturations) of ginger rhizome, was detected on polyacrylamide gels after native polyacrylamide gel electrophoresis (PAGE) or sodium dodecyl sulfate (SDS)-PAGE. The gel was submerged in a 50 mM Tris-HCl buffer (pH 7.9) containing 13 mM glutathione and 0.004% hydrogen peroxide with gentle shaking for 10-20 min. The GSH-Px activity was stained with a solution containing 1.2 mM 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 1.6 mM phenazine methosulfate (PMS) for 10 min. The clear zone of GSH-Px activity on a purple background was found in both native and SDS-PAGE gels. This fast and sensitive method can be used in the process of enzyme purification and characterization of mammalian or plant cells.
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PMID:Activity staining of glutathione peroxidase after electrophoresis on native and sodium dodecyl sulfate polyacrylamide gels. 1187 Jul 57

The fermentation conditions for production of glutathione by recombinant E. coli were investigated, the addition of certain materials, such as yeast extract, precusor amino acids and ATP were mainly focused on. The results showed that the addition of precusor amino acids and ATP could promote intracellular GSH accumulation. DCW and intracellular GSH content would be 24% and 1.4 times higher than that of fermentation without additions when 2.0 g/L ATP and 9 mmol/L precusor amino acids were added at the begining and 12 h of fermentation, respectively. By using the optimized combination of additives obtained from orthogonal experiments, the maximal DCW and total GSH in broth could be improved 10% and 26% higher than the best results in orthogonal experiments, respectively. Based on the analysis of glucose utilizing ability of this strain, an exponential fed-batch culture process was conducted. DCW and total GSH in broth culd be 8.3 and 4.6 times higher than that of shaking flask culture and finally reached 80 g/L and 880 mg/L, respectively.
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PMID:[Fermentation conditions for production of glutathione by recombinant Escherichia coli]. 1255 76

Administration of 3,4-methylenedioxymethamphetamine (MDMA) or 3,4-methylenedioxyamphetamine (MDA) to rats produces serotonergic nerve terminal degeneration. However, they are not neurotoxic when injected directly into the brain, suggesting the requirement for peripheral metabolism of MDMA to a neurotoxic metabolite. Alpha-methyldopamine (alpha-MeDA) is a major metabolite of MDA. There are indications that a glutathione metabolite of alpha-MeDA and/or 3,4-dihydroxymethamphetamine may be responsible for the neurotoxicity and some of the behavioural effects produced by MDMA and/or MDA. The present study details the synthesis, purification and separation of the 5-(glutathion-S-yl)-alpha-MeDA and 6-(glutathion-S-yl)-alpha-MeDA regioisomers of alpha-MeDA. Incubation of MDA with human liver microsomes demonstrated that production of both glutathione adducts are related to cytochrome P450 2D6 isoform activity. Following intracerebroventricular administration (180 nmol) of either GSH adduct into Dark Agouti or Sprague-Dawley rats only 5-(glutathion-S-yl)-alpha-MeDA produced behavioural effects characterised by hyperactivity, teeth chattering, tremor/trembling, head weaving, splayed posture, clonus and wet dog shakes. Pre-treatment with a dopamine receptor antagonist (haloperidol, 0.25 mg/kg; i.p.) attenuated hyperactivity, teeth chattering, low posture and clonus and potentiated splayed postural effects. These results indicate that MDA can be converted into two glutathione regioisomers by human liver microsomes, but only the 5-(glutathion-S-yl)-alpha-MeDA adduct is behaviourally active in the rat.
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PMID:Synthesis, in vitro formation, and behavioural effects of glutathione regioisomers of alpha-methyldopamine with relevance to MDA and MDMA (ecstasy). 1449 58

Parkinson's disease (PD) is the second most common neurodegenerative disease, affecting over a million people in the United States alone, and is characterized by rigidity, bradykinesia, resting tremor, and postural instability. Its main neuropathological feature is the loss of dopaminergic neurons of the substantia nigra pars compacta. However, the pathogenesis of this loss is not understood fully. One of the earliest biochemical changes seen in PD is a reduction in the levels of total glutathione, a key cellular antioxidant. Traditionally, it has been thought that this decrease in GSH levels is the consequence of increased oxidative stress, a process heavily implicated in PD pathogenesis. However, emerging evidence suggests that GSH depletion may itself play an active role in PD pathogenesis. This review aims to explore the contribution of GSH depletion to PD pathogenesis.
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PMID:Glutathione--a review on its role and significance in Parkinson's disease. 1954 4


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