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  • 1
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The cause of neuronal death in amyotrophic lateral sclerosis (ALS) is unknown. Recently, it was found that some patients with autosomal-dominant familial ALS (FALS) have point mutations in the gene that encodes Cu/Zn superoxide dismutase (SOD1). In this study of postmortem brain tissue, we examined SOD activity and quantified protein carbonyl groups, a marker of oxidative damage, in samples of frontal cortex (Brodmann area 6) from 10 control patients, three FALS patients with known SOD1 mutations (FALS-1), one autosomal-dominant FALS patient with no identifiable SOD1 mutations (FALS-0), and 11 sporadic ALS (SALS) patients. Also, we determined the activities of components of the electron transport chain (complexes I, II-III, and IV) in these samples. The cytosolic SOD activity, which is primarily SOD1 activity, was reduced by 38.8% (p 〈 0.05) in the FALS-1 patients and not significantly altered in the SALS patients or the FALS-0 patient relative to the control patients. The mitochondrial SOD activity, which is primarily SOD2 activity, was not significantly altered in the FALS-1, FALS-0, or SALS patients. The protein carbonyl content was elevated by 84.8% (p 〈 0.01) in the SALS patients relative to the control patients. Finally, the complex I activity was increased by 55.3% (p 〈 0.001) in the FALS-1 patients relative to the control patients. These results from cortical tissue demonstrate that SOD1 activity is reduced and complex I activity is increased in FALS-1 patients and that oxidative damage to proteins is increased in SALS patients.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 63 (1994), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: A defect in energy metabolism may play a role in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease. In the present study, we examined the activities of the enzymes that catalyze oxidative phosphorylation in frontal, temporal, parietal, and occipital cortex from Alzheimer's disease patients and age-matched controls. Complex I and complex II–III activities showed a small decrease in occipital cortex, but were unaffected in the other cortical areas. The most consistent change was a significant decrease of cytochrome oxidase (complex IV) activity of 25–30% in the four cortical regions examined. These results provide further evidence of a cytochrome oxidase defect in Alzheimer's disease postmortem brain tissue. A deficiency in this key energy-metabolizing enzyme could lead to a reduction in energy stores and thereby contribute to the neurodegenerative process.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 101 (1994), S. 0 
    ISSN: 1471-0528
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 7 (1961), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 60 (1993), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: It has been hypothesized that some of the functional impairments associated with aging are the result of increasing oxidative damage to mitochondrial DNA that produces defects in oxidative phosphorylation. To test this hypothesis, we examined the enzymes that catalyze oxidative phosphorylation in crude mitochondrial preparations from frontoparietal cortex of 20 rhesus monkeys (5-34 years old). Samples were assayed for complex I, complex II-III, complex IV, complex V, and citrate synthase activities. When enzyme activities were corrected for citrate synthase activities (to account for variable degrees of mitochondrial enrichment), linear regression analysis demonstrated a significant negative correlation of the activities of complex I (p 〈 0.002) and complex IV (p 〈 0.03) with age but no significant change in complex II-III or complex V activities. Relative to animals 6.9 ± 0.9 years old (n = 7), the citrate synthase-corrected activity of complex I was reduced by 17% in animals 22.5 ± 0.9 years old (n = 6) (p 〈 0.05) and by 22% in animals 30.7 ± 0.9 years old (n = 7) (p 〈 0.01). Similar age-related reductions in the activities of complexes I and IV were obtained when enzyme activities were corrected for complex II-III activity. These findings show an age-associated progressive impairment of mitochondrial complex I and complex IV activities in cerebral cortices of primates.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have made time-of-flight neutron diffraction measurements on α-manganese metal. Powder diffraction measurements were made at 14 temperatures between 15 and 305 K, and single crystal measurements were made at 15 and 300 K. We found that the crystal structure of α-Mn is tetragonal below its Néel point of 100 K, with crystal symmetry I4¯2m and magnetic (Shubnikov) symmetry PI4¯21c. In agreement with the earlier results of Yamada et al., there are six independent magnetic atoms, and we found that their moments are weakly temperature dependent. The onset of magnetic order causes slight changes in the atomic positions and in the average atomic elastic constant.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: By specific-heat, magnetization, electrical resistivity, and neutron-diffraction measurements on a single crystal we have confirmed that UNiGe orders antiferromagnetically below 50.5 K into an incommensurate phase with q=(0,1/2,−1/2)±(0,δ,δ), δ∼0.15. δ decreases continuously with decreasing temperature to ∼0.123 at 41.5 K, where the incommensurate phase vanishes in a first-order phase transition and a commensurate antiferromagnetic structure with q=(0,1/2,1/2) sets in and remains stable down to the lowest temperatures. If a magnetic field sufficient to induce a metalmagnetic transition (1–5 T) is applied along the c axis, both antiferromagnetic phases are transformed to an uncompensated AF phase with q=(0,1/3,1/3) yielding a nonzero magnetization M≈1/3×MS. The latter structure is destroyed and a complete alignment of U moments is achieved in fields above 10 T. The strikingly different B-T diagrams observed for a magnetic field applied along different crystallographic directions reflect strongly anisotropic exchange interactions.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Clinical psychology 1 (1994), S. 0 
    ISSN: 1468-2850
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Psychologie
    Notizen: The term and concept of comorbidlty has been receiving increasing currency in the psychopathology literature. Nevertheless, most uses of this term in contemporary psychopathology research do not adequately distinguish between the nature of conditions in organic medicine (which typically approximate “diseases”) and those in descriptive psychopathology (which are typically “syndromes” or, more rarely, “disorders”), and blur the distinction between latent constructs and manifest indicators. Specific problems with use of the term comorbidlty include its (a) application to childhood and personality disorders and (b) inconsistent usage. We conclude that, with the possible exception of its use to describe some organic mental disorders, application of the term comorbidlty to psychopathologlcal syndromes encourages the premature rerHcation of diagnostic entities and arguably has led to more confusion than clarification.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 6072-6074 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A single crystal of the intermetallic compound UPdSn has been studied by means of neutron diffraction using the white-beam Laue diffractometer (single-crystal diffractometer) at the Los Alamos spallation neutron source. Data were taken in the paramagnetic phase at 55 K and just below the Néel point at 37 K. The crystallographic data refine well within the space group P63mc and confirm the results obtained previously on powders, namely that the Pd and Sn atoms are ordered. At low temperature, UPdSn undergoes two phase transitions at 40 and 25 K to complicated noncollinear antiferromagnetic structures. All three pairs of magnetic domains are observed, in roughly equal populations, in the intermediate-temperature orthorhombic magnetic structure (phase I). A uranium moment of 0.863μB and canting angles φ=56.51° and θ=21.42° were obtained, in reasonable agreement with previous powder neutron data for this temperature. The observed form factor yields an orbital-to-spin moment ratio −μL/μS=2.6 which is characteristic of the trivalent f3 configuration.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 2035-2040 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A method is described to measure deformation textures in polycrystals by time-of-flight of thermal neutrons with a 2d position sensitive detector. The procedure is illustrated for a standard sample of deformed calcite limestone and results from the Los Alamos Neutron Scattering Center and the Intense Pulsed Neutron Source at Argonne National Laboratory are compared with those from more conventional neutron diffraction experiments.
    Materialart: Digitale Medien
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