1
|
Matson WR, Ackerson BJ, Tong P. Patterns in a suspension contained in a horizontally rotating cylinder. Chaos 2010; 20:041102. [PMID: 21198063 DOI: 10.1063/1.3491340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- W R Matson
- DePaul University, 2219 North Kenmore Avenue, Chicago, Illinois 60614-3504, USA
| | | | | |
Collapse
|
2
|
Yao JK, Dougherty GG, Reddy RD, Keshavan MS, Montrose DM, Matson WR, Rozen S, Krishnan RR, McEvoy J, Kaddurah-Daouk R. Altered interactions of tryptophan metabolites in first-episode neuroleptic-naive patients with schizophrenia. Mol Psychiatry 2010; 15:938-53. [PMID: 19401681 PMCID: PMC2953575 DOI: 10.1038/mp.2009.33] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Schizophrenia is characterized by complex and dynamically interacting perturbations in multiple neurochemical systems. In the past, evidence for these alterations has been collected piecemeal, limiting our understanding of the interactions among relevant biological systems. Earlier, both hyper- and hyposerotonemia were variously associated with the longitudinal course of schizophrenia, suggesting a disturbance in the central serotonin (5-hydroxytryptamine (5-HT)) function. Using a targeted electrochemistry-based metabolomics platform, we compared metabolic signatures consisting of 13 plasma tryptophan (Trp) metabolites simultaneously between first-episode neuroleptic-naive patients with schizophrenia (FENNS, n=25) and healthy controls (HC, n=30). We also compared these metabolites between FENNS at baseline (BL) and 4 weeks (4w) after antipsychotic treatment. N-acetylserotonin was increased in FENNS-BL compared with HC (P=0.0077, which remained nearly significant after Bonferroni correction). N-acetylserotonin/Trp and melatonin (Mel)/serotonin ratios were higher, and Mel/N-acetylserotonin ratio was lower in FENNS-BL (all P-values<0.0029), but not after treatment, compared with HC volunteers. All three groups had highly significant correlations between Trp and its metabolites, Mel, kynurenine, 3-hydroxykynurenine and tryptamine. However, in the HC, but in neither of the FENNS groups, serotonin was highly correlated with Trp, Mel, kynurenine or tryptamine, and 5-hydroxyindoleacetic acid (5HIAA) was highly correlated with Trp, Mel, kynurenine or 3-hydroxykynurenine. A significant difference between HC and FENNS-BL was further shown only for the Trp-5HIAA correlation. Thus, some metabolite interactions within the Trp pathway seem to be altered in the FENNS-BL patients. Conversion of serotonin to N-acetylserotonin by serotonin N-acetyltransferase may be upregulated in FENNS patients, possibly related to the observed alteration in Trp-5HIAA correlation. Considering N-acetylserotonin as a potent antioxidant, such increases in N-acetylserotonin might be a compensatory response to increased oxidative stress, implicated in the pathogenesis of schizophrenia.
Collapse
Affiliation(s)
- JK Yao
- VA Pittsburgh Healthcare System, Pittsburgh, PA, USA, Department of Psychiatry, Western Psychiatric Institute & Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA, USA, Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA, USA
| | - GG Dougherty
- VA Pittsburgh Healthcare System, Pittsburgh, PA, USA, Department of Psychiatry, Western Psychiatric Institute & Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - RD Reddy
- VA Pittsburgh Healthcare System, Pittsburgh, PA, USA, Department of Psychiatry, Western Psychiatric Institute & Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - MS Keshavan
- Department of Psychiatry, Western Psychiatric Institute & Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA, USA, Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, USA, Department of Psychiatry, Beth Israel Deaconess Medical Center and Harvard University, Boston, MA, USA
| | - DM Montrose
- Department of Psychiatry, Western Psychiatric Institute & Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - WR Matson
- Bedford VA Medical Center, Bedford, MA, USA
| | - S Rozen
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - RR Krishnan
- Duke University Medical Center, Durham, NC, USA
| | - J McEvoy
- Duke University Medical Center, Durham, NC, USA
| | | |
Collapse
|
3
|
Matson WR, Kalyankar M, Ackerson BJ, Tong P. Concentration and velocity patterns in a horizontal rotating suspension of non-Brownian settling particles. Phys Rev E 2005; 71:031401. [PMID: 15903425 DOI: 10.1103/physreve.71.031401] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2004] [Indexed: 11/07/2022]
Abstract
We report a systematic experimental study of concentration and velocity patterns formed in a horizontal rotating cylinder filled completely with a monodisperse suspension of non-Brownian settling particles. The system shows a series of concentration and velocity patterns, or phases, with varying rotation rate and solvent viscosity. Individual phases are studied using both side and cross-sectional imaging to examine the detailed flow structures. The overall phase diagram of the system is mapped out as a function of the rotation rate and solvent viscosity. Attempts are made to analyze the functional form of the phase boundaries in order to understand the transition mechanism between different phases.
Collapse
Affiliation(s)
- W R Matson
- Department of Physics, Oklahoma State University, Stillwater, 74078, USA
| | | | | | | |
Collapse
|
4
|
Milbury PE, Vaughan MR, Farley S, Matula GJ, Convertino VA, Matson WR. A comparative bear model for immobility-induced osteopenia. URSUS 2003; 10:507-20. [PMID: 12744261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
The National Institutes of Health (NIH) and the National Aeronautics and Space Administration (NASA) are seeking solutions to the human problem of osteopenia, or immobility-induced bone loss. Bears, during winter dormancy, appear uniquely exempted from the debilitating effects of immobility osteopenia. NIH and ESA, Inc. are creating a large database of metabolic information on human ambulatory and bedrest plasma samples for comparison with metabolic data obtained from bear plasma samples collected in different seasons. The database generated from NASA's HR113 human bedrest study showed a clear difference between plasma samples of ambulatory and immobile subjects through cluster analysis using compounds determined by high performance liquid chromatography with coulometric electrochemical array detection (HPLC-EC). We collected plasma samples from black bears (Ursus americanus) across 4 seasons and from 3 areas and subjected them to similar analysis, with particular attention to compounds that changed significantly in the NASA human study. We found seasonal differences in 28 known compounds and 33 unknown compounds. A final database contained 40 known and 120 unknown peaks that were reliably assayed in all bear and human samples; these were the primary data set for interspecies comparison. Six unidentified compounds changed significantly but differentially in wintering bears and immobile humans. The data are discussed in light of current theories regarding dormancy, starvation, and anabolic metabolism. Work is in progress by ESA Laboratories on a larger database to confirm these findings prior to a chemical isolation and identification effort. This research could lead to new pharmaceuticals or dietary interventions for the treatment of immobility osteopenia.
Collapse
Affiliation(s)
- P E Milbury
- Long Range Research Department, ESA, Inc., Chelmsford, MA 01824-4171, USA.
| | | | | | | | | | | |
Collapse
|
5
|
Matson WR, Ackerson BJ, Tong P. Pattern formation in a rotating suspension of non-Brownian settling particles. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 67:050301. [PMID: 12786120 DOI: 10.1103/physreve.67.050301] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2002] [Indexed: 05/24/2023]
Abstract
We report band formation and other pattern formation for a settling suspension of uniform non-Brownian particles in a completely filled horizontal rotating cylinder. The system shows a series of sharp pattern changes that are mapped out as a function of the rotation period and suspension viscosity. The experiment suggests that a large number of patterns and rich dynamics result from the interplay among the viscous drag, and gravitational and centrifugal forces.
Collapse
Affiliation(s)
- W R Matson
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | | | | |
Collapse
|
6
|
Szydlowski FJ, Dunmire DL, Peck EE, Eggers RL, Matson WR. Simultaneous determination of iron(II), iron(III), and total iron in sphagnum moss peat by programmable voltammetry on a graphite tubular electrode. Anal Chem 2002. [DOI: 10.1021/ac00225a016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
7
|
|
8
|
Jeitner TM, Bogdanov MB, Matson WR, Daikhin Y, Yudkoff M, Folk JE, Steinman L, Browne SE, Beal MF, Blass JP, Cooper AJ. N(epsilon)-(gamma-L-glutamyl)-L-lysine (GGEL) is increased in cerebrospinal fluid of patients with Huntington's disease. J Neurochem 2001; 79:1109-12. [PMID: 11739625 DOI: 10.1046/j.1471-4159.2001.00673.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pathological-length polyglutamine (Q(n)) expansions, such as those that occur in the huntingtin protein (htt) in Huntington's disease (HD), are excellent substrates for tissue transglutaminase in vitro, and transglutaminase activity is increased in post-mortem HD brain. However, direct evidence for the participation of tissue transglutaminase (or other transglutaminases) in HD patients in vivo is scarce. We now report that levels of N(epsilon)-(gamma-L-glutamyl)-L-lysine (GGEL)--a 'marker' isodipeptide produced by the transglutaminase reaction--are elevated in the CSF of HD patients (708 +/- 41 pmol/mL, SEM, n = 36) vs. control CSF (228 +/- 36, n = 27); p < 0.0001. These data support the hypothesis that transglutaminase activity is increased in HD brain in vivo.
Collapse
Affiliation(s)
- T M Jeitner
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Vigneau-Callahan KE, Shestopalov AI, Milbury PE, Matson WR, Kristal BS. Characterization of diet-dependent metabolic serotypes: analytical and biological variability issues in rats. J Nutr 2001; 131:924S-932S. [PMID: 11238787 DOI: 10.1093/jn/131.3.924s] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This report, the first in a series on diet-dependent changes in the serum metabolome (metabolic serotype), describes validation of the use of high performance liquid chromatography (HPLC) separations coupled with Coulometric array detectors to characterize changes in the metabolome. The long-term aim of these studies is to improve understanding of the effects of significant variation in nutritive status on physiology and on disease processes. Initial studies focus on identifying the effects of dietary (or caloric) restriction on the redox-active components of rat serum. Identification of compounds of interest is being carried out using HPLC separations coupled with coulometric array analysis, an approach allowing simultaneous examination of nearly 1200 serum compounds. The technical and practical issues discussed in this report are related to both analytical validity (HPLC running conditions, computer-automated peak identification, mathematical compensation for chromatographic drift, etc.) and biological variability (individual variability, cohort-cohort variability, outliers). Attention to these issues suggests approximately 250 compounds in serum are sufficiently reliable, both analytically and biologically, for potential use in building mathematical models of serotype.
Collapse
|
10
|
Abstract
Type I diabetes in rodents is associated with a spectrum of liver mitochondrial abnormalities ranging from evidence of oxidative stress and altered antioxidant defenses to frank defects in respiration rates and respiratory control ratios. To better address the myriad changes in redox metabolism in these mitochondria, we have applied new chromatographic techniques that enable simultaneous analysis of multiple components of pathways of interest (e.g., purine catabolites and oxidation by-products). We report here a portion of these results, which, in conjunction with other reported data, suggest that purine catabolism may contribute to mitochondrial antioxidant defenses by producing the antioxidant urate. In liver mitochondria from diabetic rats, increases in uric acid (threefold) and its direct precursor xanthine (sixfold) were observed in moderate diabetes, but levels fell essentially to normal in severe disease. Failure to maintain elevated xanthine and uric acid occurred contemporaneously with progressive mitochondrial dysfunction. Regression analysis revealed altered precursor-product relationships between xanthine, its precursors, and uric acid. An independent set of studies in isolated rat liver mitochondria showed that mitochondrial respiration was associated with essentially uniform decreases (approximately 30%) in all purine catabolites measured (urate, xanthine, hypoxanthine, guanine, guanosine, and xanthosine). That result suggests the potential for steady production of urate. Taken together, the two studies raise the possibility that purine catabolism may be a previously unappreciated component of the homeostatic response of mitochondria to oxidant stress and may play a critical role in slowing progressive mitochondrial dysfunction in certain disease states.
Collapse
Affiliation(s)
- B S Kristal
- Dementia Research Service, Burke Medical Research Institute, White Plains, New York, 10605, USA.
| | | | | | | |
Collapse
|
11
|
Bogdanov MB, Beal MF, McCabe DR, Griffin RM, Matson WR. A carbon column-based liquid chromatography electrochemical approach to routine 8-hydroxy-2'-deoxyguanosine measurements in urine and other biologic matrices: a one-year evaluation of methods. Free Radic Biol Med 1999; 27:647-66. [PMID: 10490286 DOI: 10.1016/s0891-5849(99)00113-6] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
8-Hydroxy-2'-deoxyguanosine (8OH2'dG) is a principal stable marker of hydroxyl radical damage to DNA. It has been related to a wide variety of disorders and environmental insults, and has been proposed as a useful systematic marker of oxidative stress. Analytic procedures for 8OH2'dG in DNA digests are well established; however, routine measurement of free 8OH2'dG in other body fluids such as urine or plasma has been problematic. This has hindered its evaluation as a general clinical, therapeutic monitoring, or environmental assessment tool. Therefore, we developed a liquid chromatography electrochemical column-switching system based on the use of the unique purine selectivity of porous carbon columns that allows routine accurate measurement of 8OH2'dG in a variety of biologic matrices. This paper describes the rationale of the system design and the protocols developed for 8OH2'dG in urine, plasma, cerebrospinal fluid, tissue, DNA, saliva, sweat, kidney dialysis fluid, foods, feces, culture matrix, and microdialysates. Concentrations in both human and animal body fluids and tissues are reported. The system performance is discussed in the context of a 1-year evaluation of the methods applied to approximately 3600 samples, using internal quality control and external blind testing to determine long-term accuracy. The methods are reliable and accurate, and therefore should prove useful in assessing the role and utility of oxidative DNA damage in aging and human illness.
Collapse
Affiliation(s)
- M B Bogdanov
- Neurochemistry Laboratory, Neurology Service, Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA.
| | | | | | | | | |
Collapse
|
12
|
Loeffler DA, LeWitt PA, Juneau PL, Camp DM, DeMaggio AJ, Havaich MK, Milbury PE, Matson WR. Influence of repeated levodopa administration on rabbit striatal serotonin metabolism, and comparison between striatal and CSF alterations. Neurochem Res 1998; 23:1521-5. [PMID: 9821156 DOI: 10.1023/a:1020923919560] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Parkinson's disease (PD) is characterized by decreased striatal dopamine, but serotonin (5-HT) is also reduced. Because 5-HT decreases following a single levodopa injection, levodopa has been suggested to contribute to PD's serotonergic deficits. However, in a recent study, rat striatal serotonin levels were reported to increase following 15-day levodopa administration. To address this issue, we administered levodopa (50 mg/kg) to rabbits for 5 days, then measured serotonin, its precursors tryptophan and 5-hydroxytryptophan (5-HTP), and its major metabolite 5-hydroxyindole-acetic acid (5-HIAA) in striatum and CSF. Striatal serotonin and tryptophan were unchanged, while 5-HTP and 5-HIAA increased 4- and 7-fold, respectively. CSF 5-HTP and 5-HIAA were also significantly increased. In levodopa-treated animals, 5-HTP concentrations were moderately correlated (r = 0.679) between striatum and CSF, while weak correlations were present between striatal and CSF concentrations of both serotonin and 5-HIAA. These results suggest that repeated levodopa treatment increases striatal serotonin turnover without changing serotonin content. However, levodopa-induced alterations in striatal serotonin metabolism may not be accurately reflected by measurement of serotonin and 5-HIAA in CSF.
Collapse
Affiliation(s)
- D A Loeffler
- Clinical Neuroscience Program, Sinai Hospital, Detroit, MI 48235, USA
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Kristal BS, Vigneau-Callahan KE, Matson WR. Simultaneous analysis of the majority of low-molecular-weight, redox-active compounds from mitochondria. Anal Biochem 1998; 263:18-25. [PMID: 9750137 DOI: 10.1006/abio.1998.2831] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies of the interaction between oxidative stress and mitochondrial dysfunction are complicated by analytical limitations, especially the need to assess multiple parameters in relatively small samples. We have addressed this problem by developing a methodology for the simultaneous analysis of the majority of low-molecular-weight, redox-active compounds from mitochondria using HPLC separations followed by coulometric array detection. The method described should also be applicable for the study of redox-active compounds in other subcellular organelles as well as in intact cells and tissues. The protocol described enables simultaneous measurement of antioxidants (e.g., tocopherols, ascorbate, lipoates, uric acid, and glutathione), markers of oxidative stress (e.g., o-tyrosine, m-tyrosine, nitrotyrosine, dityrosine, glutathione disulfide, and 8-hydroxydeoxyguanosine) as well as other metabolites (e.g., purines and indoles). In all, ca. 600 redox active compounds can be detected, most with a limit of detection of approximately 5 pg on column. Results, including analytical parameters, from a study of liver mitochondria from control and diabetic rats are presented to demonstrate utility of this methodology.
Collapse
Affiliation(s)
- B S Kristal
- Dementia Research Service, Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, New York 10605, USA.
| | | | | |
Collapse
|
14
|
Loeffler DA, LeWitt PA, Juneau PL, Camp DM, DeMaggio AJ, Milbury P, Matson WR, Rathbone MP. Altered guanosine and guanine concentrations in rabbit striatum following increased dopamine turnover. Brain Res Bull 1998; 45:297-9. [PMID: 9510422 DOI: 10.1016/s0361-9230(97)00367-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The significance of guanine nucleotides and nucleosides in neurodegenerative disorders is suggested by recent reports that these molecules enhance neurite branching and astrocyte proliferation. The objective of this study was to investigate the influence of increased dopamine metabolism, produced by 5-day treatment of rabbits with reserpine (2 mg/kg) or levodopa (LD) (50 mg/kg), on striatal concentrations of guanosine, guanine, and their metabolites. Reserpine treatment decreased striatal guanosine by 41% and increased guanine by 50%, while LD decreased guanosine by 48% (all p < 0.01 vs. vehicle-treated controls). LD also increased guanine by 22% (not statistically significant). Xanthine and uric acid concentrations were unchanged. Because of the neurotrophic properties of guanosine and guanine, changes in striatal concentrations of these purines secondary to increased dopamine (DA) turnover may have relevance for survival of remaining dopaminergic neurons in Parkinson's disease (PD).
Collapse
Affiliation(s)
- D A Loeffler
- Clinical Neuroscience Program, Sinai Hospital, Detroit, MI 48235, USA
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Loeffler DA, LeWitt PA, DeMaggio AJ, Juneau PL, Milbury PE, Matson WR. Markers of dopamine depletion and compensatory response in striatum and cerebrospinal fluid. J Neural Transm Park Dis Dement Sect 1995; 9:45-53. [PMID: 7605589 DOI: 10.1007/bf02252962] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Though depletion of CSF homovanillic acid (HVA) concentration has often been regarded as a direct indicator of dopamine (DA) deficiency in Parkinson's Disease (PD), CSF HVA is normal in mildly affected patients. To explore why, we measured DA and its metabolites in striatum and CSF in rabbits receiving reserpine for 5 days. Reserpine, which depletes striatal DA by disrupting vesicular storage of the neurotransmitter, results in a compensatory increase of DA turnover. In response to a 96% depletion of striatal DA, its catabolic intermediates 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxytyramine (3-MT) decreased 64% and 92% in striatum, although the endproduct, HVA, was unchanged. In contrast, CSF concentrations of HVA and DOPAC increased significantly, though 3-MT and levodopa (LD) were unaltered. A 5-fold rise in striatal LD concentration after reserpine-induced DA depletion provided evidence for enhanced DA synthesis. As in PD, the compensatory increase of DA synthesis after reserpine administration confounds the ability of CSF HVA to reflect DA depletion.
Collapse
Affiliation(s)
- D A Loeffler
- Clinical Neuroscience Center, Sinai Hospital, Wayne State University School of Medicine, Detroit, Michigan, USA
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
We measured metabolites of tyrosine and tryptophan (TRP) in the frontal cortex, putamen (PT), and pars compacta of the substantia nigra (SN) of control and Parkinson's disease (PD) brain tissues. Dopamine concentrations were significantly decreased in the PT and SN of PD tissue, regardless of L-dopa therapy. However, 3-O-methyldopa (3OMD) concentration showed a significant increase in each region of the PD group treated with L-dopa (PD[+]) as compared with both the control group and the PD group without L-dopa therapy (PD[-]). Therefore, 3OMD concentration appears to be a reliable marker of L-dopa therapy. Serotonin concentration was lower in each region of the PD groups than in the control group. Although the magnitude of decrease was greater in the PD(+) group, there was no statistical significance between the two PD groups. The same patterns of decrease were present in kynurenine (KYN) and kynurenic acid (KYA) concentrations, but the molar ratios of TRP to KYN and KYN to KYA were unchanged among three groups. In contrast, 3-hydroxykynurenine (3OHKY) concentration was increased in the PT PD(-) group and in three regions of the PD(+) group. Since the KYN pathway leads to formation of nicotinamide-adenine dinucleotide (NADH), the present results may be a further indication of a defect in NADH:ubiquinone oxidoreductase (complex I) in mitochondria in PD.
Collapse
Affiliation(s)
- T Ogawa
- Brain Tissue Resource Center, McLean Hospital, Belmont, MA 02178
| | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
Transient hypercapnic hyperoxemia was induced in two Rett syndrome children by the administration of a gaseous mixture of 80% O2 and 20% CO2. Time course studies of neurotransmitters and their metabolites showed an immediate and marked increase in central biogenic amine turnover following inhalation of the gas mixture. The increased turnover of biogenic amines was associated with improved clinical changes. This suggests a coupled relationship and provides further support for an etiological role of neurotransmitter dysfunction in Rett syndrome. In a complementary study, elevation of pulmonary CO2 by application of a simple rebreathing device resulted in improvement of abnormal blood gases and elimination of the Cheyne-Stokes-like respiratory pattern of the Rett syndrome. Near normalization of the EEG occurred when a normal respiratory pattern was imposed by means of a respirator. Taken together, these results lead to the preliminary conclusion that cerebral hypoxemia secondary to abnormal respiratory function may contribute to diminished production of biogenic amines in Rett syndrome.
Collapse
Affiliation(s)
- R Pelligra
- Ames Research Center, National Aeronautics and Space Administration (NASA), Moffett Field, CA 94035
| | | | | | | | | |
Collapse
|
18
|
Abstract
Huntington's disease (HD) is characterized by gradually evolving selective neuronal death. Several lines of evidence suggest that an excitotoxic mechanism may play a role. Tryptophan metabolism leads to production of quinolinic acid, an N-methyl-D-aspartate (NMDA) receptor agonist, and to kynurenic acid, an antagonist at these same receptors. We recently found increased kynurenine to kynurenic acid ratios in HD postmortem putamen and decreased kynurenic acid concentrations in cerebrospinal fluid, consistent with decreased formation of kynurenic acid in HD brain. In the present study we used HPLC with 16 sensor coulometric electrochemical detection to measure kynurenic acid and 18 other electrochemically active compounds in 6 cortical regions, caudate and cerebellum from controls, HD, Alzheimer's disease (AD), and Parkinson's disease (PD) patients. Significant reductions in kynurenic acid concentrations were found in 5 of 6 cortical regions examined. Smaller reductions of kynurenic acid in the caudate, cerebellum and frontal pole were not significant. No significant reductions were found in the AD and PD patients. Both uric acid and glutathionine were significantly reduced in several regions of HD cerebral cortex, which could signify abnormal energy metabolism in HD. Since kynurenic acid is an antagonist of excitatory amino acid receptors, a deficiency could contribute to the pathogenesis of neuronal degeneration in HD.
Collapse
Affiliation(s)
- M F Beal
- Department of Neurology, Massachusetts General Hospital, Boston 02114
| | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
BACKGROUND AND PURPOSE Increases in uric acid follow experimental stroke, which may be related to free radical formation by xanthine oxidase. The present study examined the time course of changes in xanthine and uric acid and their relationship to changes in the free radical scavengers glutathione, cysteine, and ascorbic acid. METHODS Focal ischemia was induced by occluding the middle cerebral artery, followed by transient occlusion of the common carotid arteries for 60 minutes. At varying time points, animals were sacrificed, and ischemic cortex was dissected. Neurochemical measurements were made by high-performance liquid chromatography with 16-sensor electrochemical detection. RESULTS Marked increases in uric acid were seen at all time points, with a maximal increase at 1 day and a persistent increase lasting up to 21 days. There were smaller reciprocal decreases in xanthine. Glutathione, cysteine, and ascorbic acid showed significant decreases, consistent with the generation of free radicals. Reductions in levels of cysteine and glutathione were significantly correlated with increases in uric acid levels. CONCLUSIONS These findings confirm marked alterations in purine metabolism following focal ischemia and suggest that xanthine oxidase contributes to the generation of free radicals.
Collapse
Affiliation(s)
- Y Uemura
- Stroke Research Laboratory, Massachusetts General Hospital, Boston 02114
| | | | | | | |
Collapse
|
20
|
During MJ, Heyes MP, Freese A, Swartz KJ, Matson WR, Markey SP, Martin JB, Roth RH. Indolic and kynurenine pathway metabolites of tryptophan in rat brain: effect of precursor availability on in vivo release. Adv Exp Med Biol 1991; 294:535-9. [PMID: 1837690 DOI: 10.1007/978-1-4684-5952-4_62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- M J During
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Beal MF, Matson WR, Swartz KJ, Gamache PH, Bird ED. Kynurenine pathway measurements in Huntington's disease striatum: evidence for reduced formation of kynurenic acid. J Neurochem 1990; 55:1327-39. [PMID: 2144582 DOI: 10.1111/j.1471-4159.1990.tb03143.x] [Citation(s) in RCA: 222] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recent evidence suggests that there may be overactivation of the N-methyl-D-aspartate (NMDA) subtype of excitatory amino acid receptors in Huntington's disease (HD). Tryptophan metabolism by the kynurenine pathway produces both quinolinic acid, an NMDA receptor agonist, and kynurenic acid, an NMDA receptor antagonist. In the present study, multiple components of the tyrosine and tryptophan metabolic pathways were quantified in postmortem putamen of 35 control and 30 HD patients, using HPLC with 16-sensor electrochemical detection. Consistent with previous reports in HD putamen, there were significant increases in 5-hydroxyindoleacetic acid, 5-hydroxytryptophan, and serotonin concentrations. Within the kynurenine pathway, the ratio of kynurenine to kynurenic acid was significantly (p less than 0.01) increased twofold in HD patients as compared with controls, consistent with reduced formation of kynurenic acid in HD. CSF concentrations of kynurenic acid were significantly reduced in HD patients as compared with controls and patients with other neurologic diseases. Because kynurenic acid is an endogenous inhibitor of excitatory neurotransmission and can block excitotoxic degeneration in vivo, a relative deficiency of this compound could directly contribute to neuronal degeneration in HD.
Collapse
Affiliation(s)
- M F Beal
- Department of Neurology, Massachusetts General Hospital, Boston 02114
| | | | | | | | | |
Collapse
|
22
|
Godefroy F, Matson WR, Gamache PH, Weil-Fugazza J. Simultaneous measurements of tryptophan and its metabolites, kynurenine and serotonin, in the superficial layers of the spinal dorsal horn. A study in normal and arthritic rats. Brain Res 1990; 526:169-72. [PMID: 2078814 DOI: 10.1016/0006-8993(90)90267-f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It has been demonstrated that 5-hydroxytryptamine (5-HT) is not the only neuroactive metabolite of tryptophan (TRP) in the CNS. The presence of kynurenine (KYN) and its metabolites has been reported in the brain of several mammalian species and the neuroactive properties of these compounds are now well established. In the present study, we report the identification of KYN in the superficial layers of the rat spinal dorsal horn. KYN was measured simultaneously with TRP. 5-hydroxytryptophan, 5-HT, 5-hydroxyindoleacetic acid and 5-HT-O-sulfate by means of liquid chromatography with coulometric electrode array detection. The results observed in the normal rat and in an animal model of persistent pain, the arthritic rat, are discussed in view of the hypothesis relating to the involvement of the bulbospinal serotonergic system in pain mechanisms and of the possible participation of KYN and its metabolites in these mechanisms.
Collapse
Affiliation(s)
- F Godefroy
- Unité de Recherches de Physiopharmacologie du Système Nerveux de l'I.N.S.E.R.M. (U. 161), Paris, France
| | | | | | | |
Collapse
|
23
|
Swartz KJ, Matson WR, MacGarvey U, Ryan EA, Beal MF. Measurement of kynurenic acid in mammalian brain extracts and cerebrospinal fluid by high-performance liquid chromatography with fluorometric and coulometric electrode array detection. Anal Biochem 1990; 185:363-76. [PMID: 2339792 DOI: 10.1016/0003-2697(90)90309-w] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Kynurenic acid is a broad-spectrum excitatory amino acid (EAA) receptor antagonist which is present in the mammalian central nervous system. We describe a method for the measurement of kynurenic acid using isocratic reverse-phase high-performance liquid chromatography (HPLC) with fluorometric detection enhanced by Zn2+ as a postcolumn reagent. The method requires no prior sample preparation procedures other than extraction with 0.1 M HClO4. The reliability of the primary fluorometric method was verified by comparing measurements of tissue concentrations of kynurenic acid in human cerebral cortex and putamen using three different methods of separation with fluorometric detection, as well as four methods utilizing HPLC with coulometric electrode array system (CEAS) detection. All seven methods produced comparable results. The concentration of kynurenic acid in human cerebral cortex was 2.07 +/- 0.61 pmol/mg protein, and in human putamen, 3.38 +/- 0.81 pmol/mg protein. Kynurenic acid was also found to be present in human cerebrospinal fluid (CSF) at a concentration of 5.09 +/- 1.04 nM. The regional distribution of kynurenic acid in the rat brain was examined. Kynurenic acid concentrations were highest in brainstem (149.6 fmol/mg protein) and olfactory bulb (103.9 fmol/mg protein) and lowest in thalamus (26.0 fmol/mg protein). There were no significant postmortem changes in kynurenic acid concentrations in cerebral cortex, hippocampus, and striatum at intervals ranging from 0 to 24 h. Perfusion of the cerebral vasculature with normal saline prior to sacrifice did not significantly alter kynurenic acid content in rat hippocampus, cerebral cortex, or striatum. The analytical methods described are the most sensitive (10-30 fmol injection-1) and specific (utilizing both excitation and emissions properties and electrochemical reaction potentials, respectively) methods for determining kynurenic acid in brain tissue extracts and CSF. These methods should prove useful in examining whether kynurenic acid modulates EAA-mediated neurotransmission under physiologic conditions, as well as in determining the role of kynurenic acid in excitotoxic neuronal death.
Collapse
Affiliation(s)
- K J Swartz
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115
| | | | | | | | | |
Collapse
|
24
|
Abstract
Six female cats, varying in susceptibility to motion sickness, were implanted with chronic cannulae in the rostral portion of the fourth ventricle. The cats were then challenged with a motion sickness-inducing stimulus. Samples of cerebrospinal fluid were withdrawn before and after emesis or 30 min of motion if emesis did not occur and again on control (no motion) days. The samples were analyzed by HPLC with an array of 16 coulometric detectors. Thirty-six compounds were identified in the samples. Baseline levels of DOPAC, MHPGSO4, uric acid, DA, 5-HIAA and HVA were lower on motion and control days in cats which became motion sick when compared with cats which did not become motion sick. None of the identified compounds varied as a function of either exposure to motion or provocation of emesis. It is concluded that susceptibility to motion sickness is a manifestation of individual differences related to fundamental neurochemical composition.
Collapse
Affiliation(s)
- J B Lucot
- Department of Pharmacology, Wright State University, Dayton, OH 45435
| | | | | | | |
Collapse
|
25
|
Abstract
The use of multiple parameter assays of entire metabolic pathways is potentially a powerful tool for unraveling mechanisms of disorders or drug action and classification of neurological diseases. Coulometric electrode series array sensors, coupled with liquid chromatography (n-ELC), provide a route to multiplying the resolving power of conventional LC by factors of 10 to 50. Since the original description of the n-ELC concept by Matson et al. (1), fundamental issues of optimizing sensor design and integration with computer controlled LC systems have been addressed. Femtogram level potential time (ET) separations can now be performed for multiple components in both isocratic and gradient modes. A 56-component isocratic method for the study of the kynurenine system in Huntington's Disease (HD) is presented as an indication of the analytical definitions and nomenclature used to qualify an n-ELC procedure, and an indication of the implications of multiparameter data bases on data handling and experimental design.
Collapse
|
26
|
Sweet WH, Bouckoms AJ, Matson WR. Neurochemical correlates of trigeminal, post-traumatic, and chronic migrainous neuralgia. Pain 1987. [DOI: 10.1016/0304-3959(87)91597-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
27
|
Volicer L, Langlais PJ, Matson WR, Mark KA, Gamache PH. Serotoninergic system in dementia of the Alzheimer type. Abnormal forms of 5-hydroxytryptophan and serotonin in cerebrospinal fluid. Arch Neurol 1985; 42:1158-61. [PMID: 2415092 DOI: 10.1001/archneur.1985.04060110040013] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Serotonin (5-HT), its precursor 5-hydroxytryptophan (5-HTP), and its major metabolite 5-hydroxyindoleacetic acid (5-HIAA) were measured in the cerebrospinal fluid (CSF) of 14 patients with dementia of the Alzheimer type (DAT) and in nine controls by high-performance liquid chromatography with a novel multisensor coulometric detection system. Concentrations of both 5-HT and 5-HIAA detected by this system were lower than the concentrations obtained using conventional amperometric detection. This difference was caused by coelution of compounds that could be resolved from 5-HT and 5-HIAA by the multisensor coulometric system. One of the coelution compounds, observed in DAT but not in control CSF, behaved like a partially oxidized 5-HT. A compound behaving like partially oxidized 5-HTP was also observed in DAT CSF. Concentrations of 5-HTP, 5-HT, and 5-HIAA were lower in DAT CSF than in a corresponding fraction of control CSF. These results indicate involvement of the serotoninergic system in DAT and might lead to development of a diagnostic test for DAT.
Collapse
|
28
|
Matson WR, Gamache PH. Rapid procedure for finger-stick whole-blood analysis for serotonin by electrochemical-array-cell liquid chromatography. Clin Chem 1985. [DOI: 10.1093/clinchem/31.8.1407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
29
|
Matson WR, Gamache PH. Rapid procedure for finger-stick whole-blood analysis for serotonin by electrochemical-array-cell liquid chromatography. Clin Chem 1985; 31:1407. [PMID: 4017250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
30
|
Matson WR, Langlais P, Volicer L, Gamache PH, Bird E, Mark KA. n-Electrode three-dimensional liquid chromatography with electrochemical detection for determination of neurotransmitters. Clin Chem 1984; 30:1477-88. [PMID: 6147209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Coulometric electrodes in series have been used with liquid chromatography with electrochemical detection to increase selectivity and resolution for the direct analysis of tissue neurotransmitters. Use of three coulometric sensors for electrochemical modification, selectivity, and peak identification has been expanded into "gate" cells of three or four coulometric electrodes that allow elimination of all electrochemically irreversible substances, and "array" cells of up to 15 coulometric electrodes for separation of co-eluting compounds by their current/voltage characteristics. On-column sensitivity of the sensor arrays is 0.4 to 4 pg. Gate cell selectivity favors electrochemically reversible compounds over irreversible ones, e.g., 3-methoxy-4-hydroxyphenylglycol vs ascorbate, by a factor of up to 10(4). Resolution across the multi-electrode array cells allows separation of co-eluting compounds with half-wave potentials differing by as little as 30 to 40 mV. Cells with three to 15 electrodes have been used to measure monoamines and metabolites in brain; monoamines directly in serum filtrate; and the state of oxidation of 5-hydroxytryptamine and 5-hydroxytryptophan in cerebrospinal fluid of patients with Alzheimer's disease.
Collapse
|
31
|
Matson WR, Langlais P, Volicer L, Gamache PH, Bird E, Mark KA. n-Electrode three-dimensional liquid chromatography with electrochemical detection for determination of neurotransmitters. Clin Chem 1984. [DOI: 10.1093/clinchem/30.9.1477] [Citation(s) in RCA: 166] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Coulometric electrodes in series have been used with liquid chromatography with electrochemical detection to increase selectivity and resolution for the direct analysis of tissue neurotransmitters. Use of three coulometric sensors for electrochemical modification, selectivity, and peak identification has been expanded into "gate" cells of three or four coulometric electrodes that allow elimination of all electrochemically irreversible substances, and "array" cells of up to 15 coulometric electrodes for separation of co-eluting compounds by their current/voltage characteristics. On-column sensitivity of the sensor arrays is 0.4 to 4 pg. Gate cell selectivity favors electrochemically reversible compounds over irreversible ones, e.g., 3-methoxy-4-hydroxyphenylglycol vs ascorbate, by a factor of up to 10(4). Resolution across the multi-electrode array cells allows separation of co-eluting compounds with half-wave potentials differing by as little as 30 to 40 mV. Cells with three to 15 electrodes have been used to measure monoamines and metabolites in brain; monoamines directly in serum filtrate; and the state of oxidation of 5-hydroxytryptamine and 5-hydroxytryptophan in cerebrospinal fluid of patients with Alzheimer's disease.
Collapse
|
32
|
Zink EW, Davis PH, Griffin RM, Matson WR, Moffitt RA, Sakai DT. Direct determination of lead in evaporated milk and apple juice by anodic stripping voltammetry: collaborative study. J Assoc Off Anal Chem 1983; 66:1414-20. [PMID: 6689016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A method for the direct determination of lead in evaporated milk and in fruit juice with no prior sample digestion was successfully collaborated by 13 laboratories. The anodic stripping voltammetric (ASV) method studied consisted of adding 0.2 mL aliquots of evaporated milk or 0.3 mL aliquots of fruit juice to 2.9 mL of a dechelating reagent, Metexchange. The reagent-sample mixture is then analyzed for lead by ASV with no further sample preparation. Each collaborator received 24 samples, 2 each at 5 different levels (0.07-0.70 ppm for spiked evaporated milk and 0.09-0.87 ppm for spiked apple juice) along with duplicate practice samples of labeled lead content at each of 2 levels for each sample type. All unknowns were coded with random numbers. Approximately 69% of the reporting laboratories had never analyzed either evaporated milk or fruit juice for lead. Average time between receipt of samples and reporting of results was 1.6 days for all laboratories. The pooled variations between duplicate determinations for apple juice and evaporated milk were 0.00059 and 0.00043, respectively. The method was adopted official first action for both fruit juice and evaporated milk.
Collapse
|
33
|
Zink EW, Moffitt RA, Matson WR. Rapid direct determination of lead in evaporated milk by anodic stripping voltammetry without sample pretreatment. J Assoc Off Anal Chem 1983; 66:1409-13. [PMID: 6689015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The method presented describes the direct determination of lead in evaporated milk in which the milk ashing step prior to analysis is eliminated. Digital instrument readout units are microgram Pb/mL milk. Total analysis time after instrument calibration is less than 3 min per sample. Range of the method is 0.05-1.0 ppm lead in milk, and precision of the method expressed by relative standard deviation of duplicate pairs ranged from 30% at 0.1 micrograms/mL to 3% at 1.0 micrograms/mL of lead in milk. The method compares favorably with the AOAC official first action anodic stripping voltammetric method (25.074). In addition, the method appears to work equally well for skim evaporated milk, sweetened condensed milk, and nonfat powdered dry milk when the latter two are reconstituted with water according to product label instructions. Recovery and interference studies are presented.
Collapse
|
34
|
Davis PH, Berlandi FJ, Dullude GR, Griffin RM, Matson WR, Zink EW. Analysis of total arsenic in urine and blood by high speed anodic stripping voltammetry. Am Ind Hyg Assoc J 1978; 39:480-90. [PMID: 685828 DOI: 10.1080/0002889778507793] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A method for the measurement of parts per billion levels of total arsenic in urine and blood is described. Samples are wet ashed with a mixture of HNO3, HCIO4, and H2SO4 acids. Ashed materials are subjected to a reductillationTM procedure to reduce As (V) to As (III) and to separate arsenic from the sample matrix. Collected arsenic is then quantitated by anodic stripping voltammetry (ASV) at a gold film electrode. ASV analysis time is only 2 minutes. By simultaneous reductillation of 4 samples, ppb arsenic determinations can be accomplished at a rate of about 12 per hour. The method is as accurate, precise and reliable at the nanogram level as the more universally accepted colorimetric techniques are at the microgram and milligram levels. For replicate analysis of real samples, method precision ranged from +/- 1.4 ppb at the 5 ppb level to +/- 0.96 ppb at the 25 ppb level. Accuracy is estimated at +/- 6% over the range 5 to 500 ppb arsenic.
Collapse
|
35
|
Zink EW, Matson WR, Pfeiffer L, Pietrzyk AF. Direct analysis of lead in fruit juice by anodic stripping voltammetry with no prior sample preparation. J Assoc Off Anal Chem 1978; 61:652-9. [PMID: 649557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A method is presented for determining lead in fruit juice in less than 3 min after instrument calibration. The range examined is 0.01 to 1.3 ppm lead. The method is compared with 3 other methods in general use. Standard error of estimates between the methods compared range from 0.023 to 0.051 ppm for a set of 50 samples and from 0.037 to 0.091 ppm for a set of 9 samples. Regression correlation coefficients between methods range from 0.968 to 0.995. Judged by the comparisons, the direct method is precise and accurate over greater than a 100-fold range of lead concentrations.
Collapse
|
36
|
Abstract
Mercury liberated during coal combustion can be either discharged as vapor in the flue as or retained in the furnace ash. About 90 percent (by weight) of the mercury released from a furnace fired with pulverized coal appears to be in the vapor phase, and 10 percent remains with the furnace residual ash. For a 700-megawatt unit, approximately 2.5 kilograms of mercury per day are released.
Collapse
|
37
|
Griffin RM, Matson WR. The assessment of individual variability to trace metal insult: low-molecular-weight metal complexing agents as indicators of trace metal insult. Am Ind Hyg Assoc J 1972; 33:373-7. [PMID: 4651521 DOI: 10.1080/0002889728506667] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|