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  • 1
    Electronic Resource
    Electronic Resource
    An Ibotenate-Selective Metabotropic Glutamate Receptor: Mediates Protein Phosphorylation in Cultured Hippocampal Pyramidal Neurons (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Previous results showed that within 30 s after glutamate stimulation of cultured rat hippocampal pyramidal neurons there occurred an elevation of Ca2+ and diacylglycerol, and the phosphorylation of three acidic protein kinase C substrates, i.e., an 87-kDa protein known as myristoylated alanine-rich C kinase substrate and a 120-and a 48-kDa protein. In addition, it was suggested that a metabotropic-type glutamate receptor might be responsible for the phosphorylation observed. This work examines the ability of metabotropic and ionotropic glutamate receptor agonists to quickly activate phospholipases in 1.26 mM versus 50 nM extracellular Ca2+ by measuring the generation of inositol phosphates. NMDA, quisqualate, and trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid did not stimulate the generation of inositol phosphates in the presence of normal or low extracellular Ca2+ in pyramidal neurons. Kainate stimulated the production of inositol phosphates in the presence of 1.26 mM extracellular Ca2+ but not in 50 nM extracellular Ca2+. Other than glutamate, only ibotenate was able to stimulate the generation of inositol phosphates in both normal and low extracellular Ca2+. The maximal response to ibotenate was approximately equal to that of glutamate, when pyramidal neurons were stimulated in 50 nM extracellular Ca2+. The generation of inositol phosphates by glutamate and ibotenate could be partially blocked (50–60% reduction) by pretreatment of neurons with pertussis toxin (250 ng/ml),-suggesting that a GTP-binding protein might be involved. In addition, ibotenate stimulated the immediate phosphorylation of the same three protein kinase C substrates as glutamate. The NMDA receptor blocker MK-801 had no effect on this phosphorylation. These results suggest that the stimulation of phosphorylation in pyramidal neurons by glutamate occurs predominantly through the activation of an ibotenate-selective metabotropic glutamate receptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.62051764.x
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  • 2
    Electronic Resource
    Electronic Resource
    View on linking the particle backscattering and particle-induced x-ray emission methods of materials analysis (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 2696-2698 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method employing simultaneous counting of elastically backscattered ions and particle-induced x rays is demonstrated as a particularly simple means of measuring differential non-Rutherford proton scattering cross sections. This method eliminates the need to determine total projectile number, target atom density or detector solid angles, or to use any additional reference element. Applied to elemental analysis via x rays, this method should allow equal accuracy to be attained with L x rays as with K x rays. The method's simplicity and versatility in these applications suggest the routine linking of the two materials analysis techniques in an integrated system which lends itself to successively reducing the impact of residual uncertainties in inner shell ionization cross sections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102830
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  • 3
    Electronic Resource
    Electronic Resource
    Expression of CD26 (Dipeptidyl Peptidase IV) on Resting and Activated Human T-Lymphocytes (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 33 (1991), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: CD26 is an activation antigen which is expressed on the surface of human T-lymphocytes. It has been characterized to be the dipeptidyl peptidase IV (DPP IV). Considerable amounts of CD26 are already present on resting T-lymphocytes. The expression of CD26 is enhanced by T-cell milogens or antigens. A correlation of CD26 expression and of enhanced enzymatic activity was observed after T-cell activation. Our data indicate that not only the immunoreactivity, but also the enzymatic activity of CD26 are detectable on the cell surface. In addition, de novo expression of CD26 was demonstrated on CD26-negative T-cells after mitogenic or antigenic stimulation.CD26 expression is initiated during the G1 phase of the cell cycle. The expression occurs nearly simultaneously with HLA-DR, but later than CD25. Similar lo CD25 and HLA-DR, CD26 is not a permanent marker on the surface of T-lymphocytes, but is down-regulated after 7 days of culture. When testing the influence of interleukin I, interleukin 2, tumour necrosis factor, and interferon-γ on the expression of CD26, no effect was found on unstimulated or on mitogen-stimulated T-lymphocytes. The binding of two different monoclonal antibodies against CD26 (anti-DPP IV and anti-Tal) to resting and activated T-lymphocytes revealed a different pattern of immunoreactivity. Resting T-lymphocytes reacted stronger with anti-DPP IV than with anti-Ta I. However, binding of the two monoclonal antibodies to T-cell blasts did not show significant differences. These data indicate that CD26 may be expressed in differently modulated configurations on the surface of T-cells, which may be associated with a distinct status of activation and or function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3083.1991.tb02548.x
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  • 4
    Electronic Resource
    Electronic Resource
    Multiple minute marker chromosomes derived from Y identified by FISH in an intersexual infant (1992)
    Springer
    Human genetics 〈Berlin〉 90 (1992), S. 181-183 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Chromosomal analysis in a child with ambiguous sex showed mosaicism of at least two cell lines with one or more marker chromosomes or none at all. They were shown to be derived from the Y chromosome by fluorescent in situ hybridisation (FISH) using different DNA probes that cover parts of the long and the short arm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210772
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  • 5
    Electronic Resource
    Electronic Resource
    Cell shrinkage stimulates bradykinin-induced cell membrane potential oscillations in NIH 3T3 fibroblasts expressing the ras-oncogene (1993)
    Springer
    Pflügers Archiv 423 (1993), S. 221-224 
    Details
    ISSN: 1432-2013
    Keywords: Cell volume ; Intracellular pH ; ras oncogene ; Calcium oscillations ; Cell membrane potential ; Bradykinin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In NIH 3T3 fibroblasts expressing the Ha-ras oncogene (+ras) bradykinin leads to sustained oscillations of cell membrane potential due to oscillations of intracellular Ca2+ with subsequent activation of Ca2+-sensitive K+ channels. In cells not expressing the oncogene (-ras), bradykinin leads only to a single transient hyperpolarization of the cell membrane. The present study has been performed to elucidate the possible interaction of cell volume, intracellular pH and bradykinin-induced oscillations of the cell membrane potential. Bradykinin leads to cell shrinkage and intracellular alkalinization of both +ras cells and −ras cells. Inhibition of Na+/H+ exchanger by HOE 694 abolishes the bradykinin-induced alkalinization but does not significantly interfere with the bradykinin-induced oscillations of cell membrane potential. In contrast, prevention of bradykinin-induced cell shrinkage by simultaneous reduction of extracellular osmolarity blunts the oscillations. Thus, cell shrinkage stimulates bradykinin-induced oscillations of cell membrane potential. On the other hand, cell shrinkage alone does not elicit oscillations unless, in addition, Ca2+ entry is stimulated by ionomycin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374398
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  • 6
    Electronic Resource
    Electronic Resource
    Na+/H+ exchange and its inhibition in cardiac ischemia and reperfusion (1993)
    Springer
    Basic research in cardiology 88 (1993), S. 443-455 
    Details
    ISSN: 1435-1803
    Keywords: Na+/H+ exchange inhibition ; cardiac ischemia ; reperfusion ; intracellular pH ; intracellular Na+ ; intracellular Ca++
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The characterization of various ion transport systems has led to a better understanding of the effects, which seem to take part in the impairment of ischemic and reperfused cardiac tissue. This review discusses the role of the Na+/H+ exchange system in the pathophysiology of ischemia and reperfusion and the beneficial effects of its inhibition. At the onset of ischemia intracellular pH (pHi) decreases due to anaerobic metabolism and ATP hydrolysis, leading to an activation of Na+/H+ exchange. This in turn increases intracellular Na+ (Na+ i) and activates Na+/K+ ATPase, with a consecutive increase of energy consumption. Since cellular Na+ and Ca++ transport are coupled by the Na+/Ca++ exchange system, which depends on the Na+ gradient, the high Na+ i leads to increased intracellular Ca++ (Ca++ i). After a certain period, Na+/H+ exchange is inactivated by a decrease of extracellular pH. In case of reperfusion the acid extracellular fluid is washed out, which reactivates Na+/H+ exchange, leading to an unfavourably fast restoration of pHi and a second time to Na+ and Ca++ i overflow. High Ca++ i is assumed to be one of the main reasons for ischemic and reperfusion injury, like arrhythmias, myocardial contracture, stunning and necrosis. It seems that the inhibition of Na+/H+ exchange can interrupt this process at an early phase and prevent or delay the consequences of ischemia and reperfusion as demonstrated by numerous investigators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00795411
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of residual stresses on hardness measurements (1993)
    Springer
    Experimental mechanics 33 (1993), S. 164-168 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The RockwellC hardness,RC, was measured as a function of position on steel rings with different residual-stress profiles through the thickness. An experimental correlation between residual stress andRC was obtained. A relationship between the average pressurep of a spherical indenter, the yield strengthS y and the residual stress of the material was conceived and used in fitting the experimental data. In order to model the effects of residual stresses on the measured hardness, the von Mises-Hencky (power) yield criterion was utilized, together with an adaptation for residual stresses of the expression for the stress state under a spherical indenter, given in Shaw, Hoshi and Henry. A parameter α was introduced in our calculations to account for the effect of the nonperpendicularity of the residual stresses to the pressurep of the spherical indenter. The proposed model in large measure fits experimental hardness versus residual stress data, and results are consistent with different samples. This model can be used as a basis for the measurement of residual stresses in steel or other materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02322494
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