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  • 1
    Electronic Resource
    Electronic Resource
    Ability of Melanins to Protect Against the Radiolysis of Thymine and Thymidine (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Periodontology 2000 1 (1987), S. 0 
    Details
    ISSN: 1600-0757
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Individuals with black skin rarely get skin cancer, and melanomas, tumors arising from pigmented cells, are generally resistant to radiation therapy. The role of melanin in these two phenomena has not been defined, but oxygen-radical species have been implicated in both effects. These studies were undertaken to determine the ability of various melanins to compete for ionizing radiation-produced radicals which destroy nucleic acid bases. The ability of Sigma eumelanin (S-eumelanin) to protect against the radiolysis of thymidine in buffered solutions was compared to the protective ability of seven amino acids, including melanin precursors; bovine serum albumin, as a model protein; ficoll, as a model polysaccharide; and DNA. Both proteins and polysaccharides are known to scavenge hydroxyl radicals in cells. The concentration of thymidine after exposure to gamma radiation was determined by High Performance Liquid Chromatography (HPLC) analysis after removal of insoluble melanin by acid precipitation. S-eumelanin was more effective at competing with thymidine for free radicals than bovine serum albumin, Ficoll, or DNA, but less effective than certain of the small molecules. Several of the above compounds were also examined for ability to protect against thymine radiolysis. In addition, melanins from other sources were compared to S-eumelanin. Of these, enzymatically synthesized phaeomelanin was the most effective. The results indicate that melanins can compete for base- and nucleoside-damaging free radicals more effectively than other cellular macromolecules. Of the small molecules, the phenolic compounds had the greatest scavenging ability. In vivo, melanins are found in melanosomes bound to protein. Therefore, the relevance of these findings to the photo- and radiobiology of melanins in vivo has yet to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0749.1987.tb00394.x
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  • 2
    Electronic Resource
    Electronic Resource
    Eumelanin Causes DNA Strand Breaks and Kills Cells (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Periodontology 2000 1 (1987), S. 0 
    Details
    ISSN: 1600-0757
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Synthetic eumelanin prepared by autooxidation of D,L-DOPA causes DNA strand breaks, as determined by alkaline elution after cell lysis with detergent and proteolysis, in B16CL4 mouse melanoma cells. The melanin is toxic to the cells in the range of doses that causes strand breaks. When the melanin was incubated with the cells at 37°C in tissue culture medium, it was maximally effective after 15 to 20 min at causing strand breaks in the DNA. The extent of damage is concentration dependent, but the effect plateaus at 1 mg/ml. The nature of the interaction of the cellular DNA with melanin is consistent with strand breaks, not DNA-DNA crosslinks. The strand break damage is repaired, even in the continued presence of melanin, but repair is more rapid if the cells are washed and the melanin is removed. The form of the melanin is important for obtaining the effect. Sonication for 3 min abrogates the effect to a considerable extent, and repeated cycles of sonication can completely destroy the activity. Lost activity returns slowly with storage at 4°C. Melanin is more effective at damaging DNA in a protein-free medium. It is also DNA-damaging at 4°C, but less so than at 37°C. Preliminary studies indicate that the strand breaks caused by melanin are additive with those caused by ionizing radiation.The extent of DNA strand breaks and alkali-labile sites caused by several other melanins was also determined. Some melanins did not cause frank strand breaks, but were active in causing alkali-labile sites. It is concluded that eumelanins are potentially genotoxic, and their protective effects in vivo must be possible by virtue of their chemical and physical relationships with other molecules and structures within the cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0749.1987.tb00408.x
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  • 3
    Electronic Resource
    Electronic Resource
    Variation in the swimming velocity of Tetrahymena thermophila through the cell cycle (1985)
    Springer
    Naturwissenschaften 72 (1985), S. 381-382 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410607
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  • 4
    Electronic Resource
    Electronic Resource
    Field evidence for the oxidation of SO 2 by H 2 O 2 in cap clouds (1988)
    [s.l.] : Nature Publishing Group
    Nature 333 (1988), S. 241-243 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Controlled emissions of both SO2 and SF6 (as a reference tracer) were made in a molar ratio of 120: 1 from the top of a 20 m tower ~5 km upwind of Great Dun Fell (847 m above sea level, 54°41'N, 2°27'W). A mobile laboratory continuously travelled along a mine road, located approximately 170 ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/333241a0
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of sodium cyanate in mice bearing B16 melanoma (1986)
    Springer
    Cancer chemotherapy and pharmacology 17 (1986), S. 231-235 
    Details
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sodium cyanate injected IP at a dose level of 200 or 250 mg/kg caused a 90% or greater inhibition of the incorporation of [3H]thymidine into DNA of B16 melanoma transplanted SC in mice. Despite the inhibitory effect of sodium cyanate on precursor incorporation into DNA, no significant effect on host survival was observed when sodium cyanate was administered as a single agent in the diet, in drinking water, or by IP injection to mice that had received IP transplants of B16 melanoma. The action of melphalan and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) in prolonging the survival time of melanoma-bearing mice was not enhanced by combined treatment with sodium cyanate. However, combined injections of sodium cyanate and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) increased the survival of tumor-bearing mice significantly more than injections of BCNU alone at a lower dose than the maximum tolerated one. These data and other studies suggest that B16 melanoma may be less responsive to the action of sodium cyanate than are murine leukemic cells or rat hepatomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256690
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  • 6
    Electronic Resource
    Electronic Resource
    Protective metabolic mechanisms during liver ischemia: Transferable lessons from long-diving animals (1988)
    Springer
    Molecular and cellular biochemistry 84 (1988), S. 77-85 
    Details
    ISSN: 1573-4919
    Keywords: ischemia ; O2 lack ; high energy phosphates ; mitochondrial respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract During periods of O2 lack in liver of seals, mitochondrial respiration and adenosine triphosphate (ATP) synthesis are necessarily arrested. During such electron transfer system (ETS) arrest, the mitochondria are suspended in functionally protected states; upon resupplying O2 and adenosine diphosphate (ADP), coupled respiration and ATP synthesis can resume immediately, implying that mitochondrial electrochemical potentials required for ATP synthesis are preserved during ischemia. A similar situation occurs in the rest of the cell since ion gradients also seem to be maintained across the plasma membrane; with ion-specific channels seemingly relatively inactive, ion fluxes (e.g., K+ efflux and Ca++ influx) can be reduced, consequently reducing ATP expenditure for ion pumping. The need for making up energy shortfalls caused by ETS arrest is thus minimized, which is why anaerobic glycolysis can be held in low activity states (anaerobic ATP turnover rates being reduced in ischemia to less than 1/100 of typical normoxic rates in mammalian liver and to about 1/10 the rates expected during liver hypoperfusion in prolonged diving). As in many ectotherms, an interesting parallelism (channel arrest coupled with a proportionate metabolic arrest at the level of both glycolysis and the ETS) appears as the dominant hypoxia defense strategy in a hypoxia-tolerant mammalian organ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235195
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  • 7
    Electronic Resource
    Electronic Resource
    An empirical investigation of the specificity and sensitivity of the automatic thoughts questionnaire and dysfunctional attitudes scale (1989)
    Springer
    Journal of psychopathology and behavioral assessment 11 (1989), S. 291-311 
    Details
    ISSN: 1573-3505
    Keywords: cognitive assessments ; depression ; Automatic Thoughts Questionnaire (ATQ) ; Dysfunctional Attitudes Scale (DAS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract Cognitive assessment of depression is not well advanced and the evidence for the validity and reliability of measures is incomplete. This study examined two cognitive assessments of depression-the Automatic Thoughts Questionnaire (ATQ) and the Dysfunctional Attitudes Scale (DAS). There were two major objectives of this study. The first objective was to examine the ability of these two measures of cognitions to discriminate depressive symptomatology within a variety of sample populations-university undergraduate students, medical and psychiatric outpatients, and acute psychiatric inpatients. The second objective was to examine the ability of the ATQ and DAS succesfully to classify depressed and nondepressed patients. The results of this study suggest that the ATQ is a sensitive and specific measure of depression. Nonspecificity to the ATQ, however, was demonstrated in the substance abuse disorder group and the personality disorder group. In contrast, the DAS, although correlated with depressive symptomatology, was not found to be specific to depression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00961529
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  • 8
    Electronic Resource
    Electronic Resource
    The value of plasmid profiling in monitoringLactobacillus plantarum in silage fermentations (1986)
    Springer
    Current microbiology 13 (1986), S. 91-94 
    Details
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Two strains ofLactobacillus plantarum were used to inoculate chopped, whole plant corn in a model ensiling system. At specific intervals up to 32 days, pH values and populations of lactic acid bacteria were determined for both uninoculated and inoculated forages in 15-kg minisilos. At all times after the second day, the inoculated forage had lower pH values and higher levels of homofermentative lactobacilli than the uninoculated material. Plasmid profiling indicated that this shift was due to the added strains ofL. plantarum. This study demonstrates that plasmids of naturally occurringLactobacillus plantarum strains are stable during the ensiling process and hence can be used to monitor the succession of introduced organisms at the expense of epiphytic populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01568288
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  • 9
    Electronic Resource
    Electronic Resource
    Human cytokines, tumor necrosis factor, and interferons: Gene cloning, animal studies, and clinical trials (1988)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 36 (1988), S. 353-367 
    Details
    ISSN: 0730-2312
    Keywords: TNF ; IFN ; genes ; clinical use ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Presented is a comprehensive program designed to isolate human cytokine genes and investigate their relative induction, and to analyze cytokine activities in cell culture, animal tumor models, and human clinical trials. Human cytokine cDNAs have been isolated from a cDNA library made from normal human peripheral blood leukocytes (PBLs) treated with Sendai virus and the relative induction of tumor necrosis factor (TNF), alpha and gamma interferons (IFN-α, IFN-γ), and interleukin-1 beta IL-1β genes has been analyzed. In the Sendai virus-induced PBL system, IL-1β mRNA was shown to be approximately twofold higher than TNF or IFN-α mRNA whereas IFN-γ mRNA was 50-100-fold lower than TNF or IFN-α mRNA. The cytotoxic activity of TNF was analyzed on several cell lines and IFN-α and IFN-γ were shown to potentiate TNF cytotoxicity about 2-200-fold depending on cell lines. The LD50 for recombinant TNF in BALB/c mice was determined to be 6 × 107 U/kg and the therapeutic dose of recombinant TNF in sarcoma 180 bearing BALB/c mice was 3 × 105 U/kg, indicating a wide therapeutic index. Phase I clinical trials of recombinant TNF given I.V. indicated a tolerated dose of 150,000 U/kg with biphasic half-life (T-1/2) of 2 and 31 min following TNF injection. Phase II trials of TNF and trials of TNF combined with IFN-α are in progress. These studies indicate that cytokines such as TNF and IFN-α are subject to similar induction systems, potentiate each other's activities, and can be tolerated at specific doses for potential therapeutic use.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240360405
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and chiroptical properties of 5,7-dioxobicyclo[2.2.2]oct-2-ene and bicyclo[2.2.2]octane-2,5-dione (1985)
    s.l. : American Chemical Society
    The @journal of organic chemistry 50 (1985), S. 5528-5533 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00350a019
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