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)

Hydrogen peroxide production in reconstituted skim milk (10%) and low-fat milk by four strains lf Lactobacillus acidophilus was studied at 37 and 4 C. Strains A and B produced little, but strains C and D produced larger amounts, especially if agitated continuously during growth at 37 C or storage at 4 C. Continuous shaking was required at 4 C for C or D (4.0 X 10(8)/ml) to produce sufficient hydrogen peroxide to retard growth of Pseudomonas fragi. Flavin adenine dinucleotide stimulated the oxidation of reduced nicotinamide adenine dinucleotide by dialyzed cell-free extracts of C and D, which indicated that the reduced nicotinamide adenine dinucleotide oxidases of these strains produce hydrogen peroxide as an end product.
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PMID:Production of Hydrogen peroxide by Lactobacillus acidophilus. 676 78

We investigated the effects of an OH. (Fe2+/H2O2) generator system on erythrocyte membrane, particularly the time-course of lipid peroxidation as estimated by measurement of conjugated dienes, thiobarbituric reactive substances (TBARS), lipofuscin-like pigments, and alpha-tocopherol. Polyunsaturated fatty acids (PUFAs), especially arachidonic acid (20:4 omega 6) and docosahexenoic acid (22:6 omega 3), were also measured. Erythrocyte membranes were suspended in phosphate buffer containing Fe2+ (200 microM) and H2O2 (1.42 mM), and incubated in a shaking water bath at 37 degrees C. Initially, there was an increase in TBARS and lipofuscin-like pigments, two well-known end products of PUFA oxidative degradation, whereas PUFAs remained unchanged (incubation time: 1 h). After two or more hours of incubation, marked lipid peroxidation was noted, with the appearance of conjugated dienes and a decrease of PUFAs, indicating that lipid peroxidation had occurred after a lag phase during which TBARS were not produced from PUFAs. This suggests that another OH. target was involved.
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PMID:Lack of correlation between TBARS production and PUFA degradation during incubation of membrane erythrocytes in an OH. (Fe2+/H2O2) generator system. 777 62

Parkinson's disease, known also as striatal dopamine deficiency syndrome, is a degenerative disorder of the central nervous system characterized by akinesia, muscular rigidity, tremor at rest, and postural abnormalities. In early stages of parkinsonism, there appears to be a compensatory increase in the number of dopamine receptors to accommodate the initial loss of dopamine neurons. As the disease progresses, the number of dopamine receptors decreases, apparently due to the concomitant degeneration of dopamine target sites on striatal neurons. The loss of dopaminergic neurons in Parkinson's disease results in enhanced metabolism of dopamine, augmenting the formation of H2O2, thus leading to generation of highly neurotoxic hydroxyl radicals (OH.). The generation of free radicals can also be produced by 6-hydroxydopamine or MPTP which destroys striatal dopaminergic neurons causing parkinsonism in experimental animals as well as human beings. Studies of the substantia nigra after death in Parkinson's disease have suggested the presence of oxidative stress and depletion of reduced glutathione; a high level of total iron with reduced level of ferritin; and deficiency of mitochondrial complex I. New approaches designed to attenuate the effects of oxidative stress and to provide neuroprotection of striatal dopaminergic neurons in Parkinson's disease include blocking dopamine transporter by mazindol, blocking NMDA receptors by dizocilpine maleate, enhancing the survival of neurons by giving brain-derived neurotrophic factors, providing antioxidants such as vitamin E, or inhibiting monoamine oxidase B (MAO-B) by selegiline. Among all of these experimental therapeutic refinements, the use of selegiline has been most successful in that it has been shown that selegiline may have a neurotrophic factor-like action rescuing striatal neurons and prolonging the survival of patients with Parkinson's disease.
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PMID:Oxidative stress and antioxidant therapy in Parkinson's disease. 883 Mar 46

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

Traditional strategies for signal transduction in immunosensors are based on piezoelectric, thermometric, electrochemical, magnetic and optical methods. The use of pressure as a signal transduction method in immunosensors has not been reported previously. An immunosensor incorporating the detection of a change in pressure as the signal-transducing mechanism was investigated. A commercially available ultra-low pressure sensor was used in conjunction with a sealed chamber to assess the feasibility of this strategy. A key feature of the current approach is the use of a thin membrane (or film) in which to perform an immunoassay and subsequently to detect production of gas. The thinness contributes to efficient gas evolution and minimizes the effect of liquid acting as a "sink" for gas molecules. This feature also simplifies measurement of evolved gas, which traditionally was based on the use of bulk solutions, shaking and pH changes to "release" dissolved gas (especially carbon dioxide). Gas generation in the current approach is achieved by the coupling of catalase to haptens or antibodies for use in competitive or sandwich immunoassays, respectively. Hydrogen peroxide is used as the substrate. Performance characteristics of the sensor apparatus were assessed in several ways. Injection of various volumes of air from a gas-tight syringe produced an essentially linear relationship from 0.2 to 2.0 microl of injected volume, with a slope of approximately 5 V/microl. Depending on the duration of the sampling period, specific signals in excess of 2 V have been obtained for 0.01 units of catalase (approximately 0.4 ng of protein). Development and use of this sensing apparatus will be described for both competitive and sandwich immunoassays.
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PMID:Development of an immunosensor based on pressure transduction. 1270 94

Wastepaper constitutes approximately half of municipal solid waste, making it a potential source of bioenergy. Newspaper was pretreated with an ammonia-hydrogen peroxide (H2O2) mixture in a shaking bath from room temperature to 80 degrees C, and then its enzymatic digestibility was measured. A significant amount of ink was removed from the newspaper slurry by the reciprocating movement of the shaking bath. In addition, the ammonia-H2O2 significantly swelled the substrate, thereby greatly increasing its susceptibility to enzymatic digestion. After pretreating the newspaper with conditions of 40 degrees C, 3 h, 130 strokes/min, and 4 wt% ammonia-2 wt% H2O2, the enzymatic digestibility was almost 90% of theoretical, or about 25% higher than that of untreated substrate. Digestibility was also investigated as a function of ammonia concentration, H2O2 concentration, shaking speed, pretreatment temperature, and time.
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PMID:Enzymatic digestibility of used newspaper treated with aqueous ammonia-hydrogen peroxide solution. 1272 59

The effect of growth and fermentation conditions on the production of catalase by T. aurantiacus WSH 03-01 was investigated in shaking flasks. Catalase activity reached 1594 u/mL when the culture was grown on a complex carbon source containing 20 g/L dextrin and 1% (V/V) ethanol, which was 23% higher than the sum produced on 20 g/L dextrin and 1% (V/V) ethanol, respectively. It was concluded that dextrin might act as a major carbon source in the complex, while ethanol was rather a stimulator than a carbon source. The stimulation effect of ethanol on catalase production was postulated to be two aspects; catalase-dependent alcohol metabolism is activated by acute alcohol, thus more catalase need to be synthesized for that use, named direct induction. As for indirect induction, which may result from little amount of H2O2 generation in process of NADH regeneration in respiratory chain. Peptone was shown to be a favorable nitrogen source for catalase production and its optimum concentration was found to be 10 g/L. Catalase production by T. aurantiacus WSH 03-01 was further improved by optimizing the initial pH, volume of medium in flasks as well as the concentration of external H2O2. Under the optimum culture conditions, the activity of catalase reached 2762 u/mL, which was nearly 6.8 times higher than that of the initiate conditions. Furthermore, the potential application of this novel catalase in the treatment of textile bleaching effluents was evaluated. Thermo-and alkaline stability of this catalase was compared with the commercial available catalases produced from bovine and Aspergillus niger. The crude enzyme from T. aurantiacus WSH 03-01 showed stronger stabilities at (70 degrees C, 80 degrees C, 90 degrees C) and (pH 9.0, pH 10.0, pH 11.0) than the other two types of catalases, indicating a great application potential in the clean production process of textile industry.
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PMID:[Thermo-alkali-stable catalase from Thermoascus aurantiacus and its potential use in textile bleaching process]. 1597 17

We investigated the effects of O2 on Bifidobacterium species using liquid shaking cultures under various O2 concentrations. Although most of the Bifidobacterium species we selected showed O2 sensitivity, two species, B. boum and B. thermophilum, demonstrated microaerophilic profiles. The growth of B. bifidum and B. longum was inhibited under high-O2 conditions accompanied by the accumulation of H2O2 in the medium, and growth was restored by adding catalase to the medium. B. boum and B. thermophilum grew well even under 20% O2 conditions without H2O2 accumulation, and growth was stimulated compared to anoxic growth. H2O-forming NADH oxidase activities were detected dominantly in cell extracts of B. boum and B. thermophilum under acidic reaction conditions (pH 5.0 to 6.0).
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PMID:Response of the microaerophilic Bifidobacterium species, B. boum and B. thermophilum, to oxygen. 1695 Sep 14

Gastrointestinal stability of venlafaxine was evaluated in vitro in simulated gastric (SGF) and intestinal (SIF) fluids using a stability indicating HPLC method. The method was validated using a 5 microm Ascentis C18 column (150 mm x 4.6 mm) and mobile phase consisting of 30% acetonitrile in 20 mM potassium phosphate buffer (pH 6.5) delivered isocratically at a flow rate of 1 mL/min with UV detection at 228 nm. Venlafaxine in USP simulated gastric and intestinal fluids (0.4 mg/mL) was incubated at 37 degrees C in a shaking water bath. The gastric stability study samples were assayed at 0, 15, 30 and 60 min intervals while sampling for the intestinal stability study was at 0, 1, 2 and 3 h. System suitability determinations gave R.S.D.s of 0.68, 0.5 and 3.9% for retention factor (k'), peak area and tailing factor, respectively. The method was shown to be accurate, precise, specific, and linear over the analytical range. Intra- and inter-day precision was <5.3%. Forced degradation studies of drug substance in basic media at 70 degrees C as well as in H2O2 for 1 h and ultra-violet photostability studies at 255 and 365 nm for 24 h did not produce any detectable degradation products. Forced degradation studies of drug substance in acidic media at 70 degrees C for 1 h produced the dehydro-venlafaxine degradant. Venlafaxine was stable in SGF (pH approximately 1.2) for the 1-h incubation period and in SIF (pH 6.8) up to 3 h with <1.5% relative difference (RD) between the amount of drug added and that found for all time points. This stability experiment in simulated gastric and intestinal fluids suggests that drug loss in the gastrointestinal tract takes place by membrane permeation rather than a degradation process.
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PMID:Validation and application of a stability-indicating HPLC method for the in vitro determination of gastric and intestinal stability of venlafaxine. 1730 Aug 96

Hydrogen peroxide in basic media is proposed as a means for dissolving whole blood samples to be analyzed by electrothermal atomization atomic absorption spectrometry, ET AAS. Approximately 2g of the whole blood sample were directly weighed in a 150mL volumetric flask; 3mL of a NaOH 0.2molL(-1) solution, two drops of 1-octanol, as an antifoaming agent, and 1mL of 30% volume hydrogen peroxide were added to the flask to promote oxidation. The solution was then manually shaken and after approximately three minutes of shaking, a clear solution, with no apparent suspended solids or greasy layers, was obtained. Distilled-deionized water was used to complete the volume. Ten muL of the resulting solution along with 10muL of a solution containing 5000mgL(-1) of NH(4)H(2)PO(4) and 300mgL(-1) of Mg(NO(3))(2) as a modifier, were injected into transversely heated graphite tubes for lead determination. Both aqueous standards and standard addition calibration curves produced results not significantly different at a 95% confidence limit level. Accuracy of the measurements was assessed by analysis of the IAEA A-13 (concentration of trace and minor elements in freeze dried animal blood) standard reference material containing 0.18mgL(-1) lead on a dry basis and by means of recovery tests. Analysis of the IAEA A-13 standard produced 0.17+/-0.02mgL(-1) lead on a dry basis; recovery tests afforded values from 95 to 105%. Ten consecutive measurements of a 5ppb lead solution gave a characteristic mass of 47.2pg and a (3S) detection limit of 1.77mugL(-1) Pb. Results obtained from analysis of whole blood samples of volunteer donors covered a lead concentration range between 8 and 21mugL(-1) with a mean value of 11.9+/-4.7mugL(-1).
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PMID:Hydrogen peroxide in basic media for whole blood sample dissolution for determination of its lead content by electrothermal atomization atomic absorption spectrometry. 1907 29


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