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  • 1
    ISSN: 1432-072X
    Keywords: Key words K+-ATPase ; Lactobacilli ; Potassium pump ; 2 ; 3-Butanedione ; Enzyme-phosphate complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lactobacillus helveticus ATCC 15009 (wild-type) membrane preparations hydrolyzed Mg2+-ATP as a function of K+ concentration (2–200 mM). Mg2+-ATP hydrolysis by L. helveticus membranes was strongly inhibited in the absence of exogenous K+, while it amounted to 6 nmol ATP hydrolyzed min–1 (mg membrane protein)–1 at 50 mM KCl (saturating conditions) and pH 7.2. The K+-dependent ATPase of L. helveticus displayed a relatively high affinity for potassium ions (K m = 800 μM) and was not affected by pretreatment of membranes with N,N’-dicyclohexylcarbodiimide. Membrane preparations were subjected to hypotonic shock to obtain a maximum yield of open profiles. The formation of a maximum level of enzyme-phosphate complex with a molecular mass of approximately 82 kDa was induced upon treatment of L. helveticus membrane preparations with low concentrations of [γ-32P]ATP in the presence of K+ and La3+ ions and was visualized by acidic SDS-PAGE. It was concluded that L. helveticus membranes contain an inwardly directed K+ pump whose presence is discussed in terms of its putative role in cytoplasmic pH regulation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 122 (1995), S. 0 
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Theoretical relationships allow the distributed deformation due to seismic activity to be quantified on the basis of the analysis of moment tensors. We apply this method to a data set consisting of seismic events that have occurred in the past 85 yr (1908–1992) along the most important seismogenic zones of the Mediterranean region. We use the Centroid Moment Tensor (CMT) Catalog prepared at Harvard University, covering the last 16 yr, and older data from Jackson & McKenzie (1988). We determine the seismic deformation and compare it to estimates of the overall deformation as obtained from global plate motion and geological studies. We generally find that the geometry of seismic deformation is similar to tectonic predictions. Even though spanning a shorter time interval, the CMT Catalog often gives a better estimate of deformation geometry than the whole data set (85 yr). Seismic deformation generally ranges from less than 10 per cent to more than 90 per cent of the total deformation. Uncertainties arise because data sets may not be representative of the long-term seismic behaviour of each zone. More reliable estimates for comparison with geodynamic processes should result from analysis of a longer time period, for which no instrumental data are available. The similarity of the deformation geometry using CMT data with tectonic expectations suggests, for several zones, the possibility of using historical data to infer longer term deformation rates based on current deformation geometry.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd.
    Alimentary pharmacology & therapeutics 11 (1997), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Margination of circulating neutrophils (PMN) into the gastric microcirculation is an early and critical event in the pathogenesis of non-steroidal antinflammatory drug (NSAID)-induced gastropathy. This effect is mediated through the upregulation of β2 integrins on the PMN surface.〈section xml:id="abs1-2"〉〈title type="main"〉Aims:To investigate whether indomethacin modulates: (1) Mac-1 expression; (2) Ca2+ mobilization ([Ca2+]i), protein kinase C and nitric oxide accumulation; and (3) mitogen-associated protein kinase phosphorylation in human PMN.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Human PMN were isolated by centrifugation through a double Ficoll gradient. [Ca2+]i was measured in PMN loaded with fura-2 and Mac-1 expression by flow cytometry.〈section xml:id="abs1-4"〉〈title type="main"〉Results:Indomethacin caused a concentration- and time-dependent upregulation of CD11b and CD18 expression and PMN adhesion to endothelial cells. Maximal upregulation of Mac-1 expression (40–50%) occurred after a 30-min incubation with 0.1 mM indomethacin. The effect was prevented by removing the Ca2+. Ionomycin and thapsigargin caused a 7–10-fold increase in [Ca2+]i and a 2–4-fold increase in Mac-1 expression. Indomethacin induced a concentration-dependent phosphorylation of a 41-kDa mitogen-associated protein kinase. Tyrosine kinase inhibitors prevented the effect of indomethacin on Mac-1 expression and Ca2+ mobilization. Indomethacin and ionomycin increased superoxide generation, myeloperoxidase secretion and PMN adherence to endothelial cells and stimulated nitric oxide production. Indomethacin-induced Mac-1 upregulation was prevented by a nitric oxide synthase inhibitor.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:Indomethacin-induced upregulation of Mac-1 is mediated by changes in [Ca2+]i and nitric oxide. Phosphorylation of the 41-kDa mitogen-associated protein isoform is a previously unreported target of NSAID action. These effects might help to explain the ability of indomethacin to cause gastric neutrophil margination.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study assesses the efficacy of the intubating laryngeal mask as a ventilation device and blind intubation guide. Following induction of anaesthesia with propofol, the device was successfully inserted at the first attempt in 110/110 (100%) patients. Placement took less than 10 s in all patients. Size selection was based on nose–chin distance. Adequate ventilation was achieved in 104/110 (95%) patients. Blind tracheal intubation using an 8-mm internal diameter straight silicone cuffed tracheal tube was attempted 3 min after the administration of vecuronium. Passage of a lighted stylet through the intubating laryngeal mask was used to determine the position of the intubating laryngeal mask cuff before blind intubation. If resistance was felt during intubation, a sequence of adjusting manoeuvres was used, based on the depth at which resistance occurred. Tracheal intubation was possible in 104/104 (100%) patients. In 42 (40%) patients, no resistance was encountered and the trachea was intubated at the first attempt. Sixty-two (60%) patients required one adjusting manoeuvre. The mean (range) time taken to successful intubation, i.e. the time from disconnection of the intubating laryngeal mask from the breathing system to successful tracheal intubation, was 79 (12–315) s. Six patients with potential or known intubation problems were included in the study. The tracheas of all six patients were successfully intubated. We conclude that the intubating laryngeal mask is an effective ventilation device and intubation guide with potential for use in patients who may present difficulty in tracheal intubation.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of plastic surgery 19 (1996), S. 47-49 
    ISSN: 1435-0130
    Keywords: Hand tumor ; Plexiform fibrohistiocytic tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of a rare and recently described neoplasm of the superficial soft tissue that occurs mainly in children and young adults is described. The lesion demonstrates morphological features reminiscent of both fibrous histiocytoma and fibromatosis. Microscopically, this tumor is characterized as a multinodular or plexiform proliferation of histiocyte- and fibroblast-like cells associated with multinuclear giant cells. Because of its unpredictable biological behavior, high recurrence rate, and potential for regional lymphatic metastasis, the diagnosis of plexiform fibrohistiocytic tumor raises important treatment considerations.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    International journal of colorectal disease 10 (1995), S. 173-180 
    ISSN: 1432-1262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le côlon humain est probablement le viscère creux de l'abdomen dont on connaît le moins l'activité motrice. Ceci résults de plusieurs facteurs: a) la partie proximale est relativement inaccessible pour des raisons anatomiques; b) il n'y a pas de modèle animal fiable en raison des différences anatomo-physiologiques considérables qui existent chez les mammifères. Par example, la plupart des déductions quant à l'activité motrice du côlon humain, résultent d'expériences chez les chats et les chiens dont le côlon présente un caecum le plus souvent atrophique et dont l'aspect est sans particularité, en forme de C, sans les haustrations et les angulations aiguës que l'on observe chez l'homme; c) les grandes fluctuations que l'on observe dans la motilité d'un même individu au cours d'une journée rendent difficiles l'interprétation de nombreuses études, particulièrement si l'on considère le fait que, jusqu'à une date récente, la plupart des études menées chez l'homme sur la motilité colique, comportaient des enregistrements sur des périodes relativement courtes (30 à 180 min). Récement, toutefois, des techniques permenttant des enregistrements de la partie proximale du côlon humain ont été développées autorisant des observations prolongées (24 h et plus) de l'activité myoélectrique et contractile permettant d'améliorer nos connaissances des propriétés physiologiques normales de cet organe. Ces données ont été intégrées par ailleurs et confirmées par des techniques scintigraphiques moins invasives permettant des mesures des flux intra-coliques. Le but de l'article présent est de faire une revue des aspects physiologiques de la motilité colique chez l'homme tout en citant les études animales lorsque des études identiques font défaut chez l'homme. Nous introduirons brièvement quelques concepts de base puis une description plus détaillée du sujet principal.
    Notes: Abstract From the point of view of its motor activity, the human colon is probably the least understood of the abdominal hollow viscera. This is due to several facts: a) its proximal portions are relatively inaccessible due to anatomical reasons; b) there is no reliable animal model due to the considerable anatomic-physiological differences among mammals. For instance, most deductions about human colonic motor activity have been drawn from experiences in cats and dogs, in which the colon displays a cecum which is almost atrophic, and the viscus is featureless and C-shaped, without the haustrations and the sharp angulations seen in man [1], c) the wide fluctuations of motility in the daily time course of the same individual makes the interpretation of many studies difficult [2, 3, 4], especially considering the fact that, until recently, most of the studies on human colonic motility have been conducted for relatively short (30–180 min) recording periods [5]. Recently, however, techniques that allow recording from the proximal portions of the human colon have been developed, and prolonged (24 h or more) observations of myoelectrical and contractile events have been achieved, thus improving our knowledge of the normal physiologic properties of the viscus [6, 7]. These informations have furthermore been integrated and confirmed by scintigraphic techniques (less invasive), that allow the measurement of intracolonic flow activity [8, 9]. The purpose of the present paper is to review the physiological aspects of colonic motility in man, quoting animal studies where human ones are lacking. We will briefly introduce some basic concepts, then a more detailed description of the main topic will follow.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Neurochemical research 22 (1997), S. 297-304 
    ISSN: 1573-6903
    Keywords: Ca2+-ATPase ; synaptosomes ; calcium ; neuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two forms of Ca2+-pump were identified in bovine brain synaptic membranes as aspartylphosphate intermediates and were characterized. The 140 kDa and 97 kDa phosphoproteins were digested by calpain, producing two phosphorylated fragments, of M.W. 124 and 80 kDa respectively, not inhibited by thapsigargin, and displayed a trypsin digestion pattern with the formation of one phosphorylatable fragment of about 80 kDa. These results suggest that both pumps belong to the Plasma Membrane-type of Ca2+ ATPases, differing from the Sarco- or Endoplasmic Reticulum kind. A plasma membrane Ca2+-ATPase proteinaceous inhibitor with molecular weight between 6,000 and 10,000 Da was resolved from synaptic terminal cytosol, where it is enriched by fourfold with respect to frontal cortex brain cytosol. Such enrichment is already evident in the correspondent crude fractions. The presence of calcium pump and its proteinaceous inhibitor inside the synaptic terminals from bovine brain is discussed in terms of free calcium level regulation in neuron synaptoplasm.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1615-6102
    Keywords: Adrenalin ; Cyclic AMP ; Ejecting process ; Epixenosomes ; Membrane receptors ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The extrusive apparatus is the most prominent and complex structure of epixenosomes. In the present paper the mechanisms activating its ejecting process were investigated by means of in vivo treatments and cytochemical procedures at the ultrastructural level. The results obtained clearly demonstrated that the ejecting process in epixenosomes is triggered by the detection of external signals through membrane receptors and the consequent activation of the adenylate cyclase-cyclic AMP system as a transduction mechanism. The membrane receptors coming into play have an affinity for soybean agglutinin and have a precise localization at the top of the organism, just where a membrane interruption appears as a first step in the whole process. The factors that trigger ejection in nature are still unknown. In the laboratory, ejection was obtained in the presence of adrenalin, which has been proved to bind to the same receptors shown to have affinity for soybean agglutinin. So epixenosomes appear to possess specific binding molecules for a mammalian hormone in the appropriate location, i.e., in the plasma membrane, and this hormone induces a precise biological response. These results are particularly interesting if we consider that epixenosomes are enigmatic organisms in which prokaryotic and eukaryotic characteristics appear to coexist.
    Type of Medium: Electronic Resource
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