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  • 2000-2004  (9)
  • 1965-1969  (30)
  • 1905-1909  (1)
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  • 11
    Electronic Resource
    Electronic Resource
    Experimental determination of the instrumental transparency function of texture goniometers (2000)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 33 (2000), S. 1162-1174 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The instrumental transparency functions of five commercially available texture goniometers were measured experimentally with six monocrystalline samples cut in different orientations from a large highly perfect silicon crystal with a rocking curve of less than 0.01°. Transparency functions were measured in steps of 0.02 to 0.2° in the pole-figure angles α, β. The window size Δα depends on the Bragg angle θ in the form 1/sinθ; the window size Δω is constant for each goniometer. The dominant instrumental parameter determining the long axis Δα of the pole-figure window is the axial width of the detector entrance slit. This parameter is smallest for area detectors (smaller by more than an order of magnitude compared with conventional scintillation detectors as well as one-dimensional position-sensitive detectors). The main features of the pole-figure window and their dependence on the instrumental parameters can be deduced fairly well from a simple geometrical model. The particular shapes of the transparency functions of the studied goniometers are markedly different. Particularly, they are not very well represented by Gauss functions. The two-dimensional transparency function can be fairly well characterized by its α and β profiles. The normalized profiles are virtually independent of the goniometer angles 2θ and α. The increasing size of the pole-figure window with decreasing θ puts a lower limit on the Bragg angle below which pole-figure measurement ceases to be meaningful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889800007251
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  • 12
    Electronic Resource
    Electronic Resource
    Serine residues 994 and 1023/25 are important for insulin receptor kinase inhibition by protein kinase C isoforms β2 and θ (2000)
    Springer
    Diabetologia 43 (2000), S. 443-449 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Insulin receptor inhibition, tyrosine kinase activity, serine phosphorylation, protein kinase C.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Inhibition of the signalling function of the human insulin receptor (HIR) is one of the principle mechanisms which induce cellular insulin resistance. It is speculated that serine residues in the insulin receptor β-subunit are involved in receptor inhibition either as inhibitory phosphorylation sites or as part of receptor domains which bind inhibitory proteins or tyrosine phosphatases. As reported earlier we prepared 16 serine to alanine point mutations of the HIR and found that serine to alanine mutants HIR-994 and HIR-1023/25 showed increased tyrosine autophosphorylation when expressed in human embryonic kidney (HEK) 293 cells. In this study we examined whether these mutant receptors have a different susceptibility to inhibition by serine kinases or an altered tyrosine kinase activity.¶Methods. Tyrosine kinase assay and transfection studies.¶Results. In an in vitro kinase assay using IRS-1 as a substrate we could detect a higher intrinsic tyrosine kinase activity of both receptor constructs. Additionally, a higher capacity to phosphorylate the adapter protein Shc in intact cells was seen. To test the inhibition by serine kinases, the receptor constructs were expressed in HEK 293 cells together with IRS-1 and protein kinase C isoforms β2 and θ. Phorbol ester stimulation of these cells reduced wild-type receptor autophosphorylation to 58 % or 55 % of the insulin simulated state, respectively. This inhibitory effect was not observed with HIR-994 and HIR-1023/25, although all other tested HIR mutants showed similar inhibition induced by protein kinase C.¶Conclusion/interpretation. The data suggest that the HIR-domain which contains the serine residues 994 and 1023/25 is important for the inhibitory effect of protein kinase C isoforms β2 and θ on insulin receptor autophosphorylation. [Diabetologia (2000) 43: 443–449]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051327
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  • 13
    Electronic Resource
    Electronic Resource
    The HIV-1 protease inhibitor indinavir impairs insulin signalling in HepG2 hepatoma cells (2000)
    Springer
    Diabetologia 43 (2000), S. 1145-1148 
    Details
    ISSN: 1432-0428
    Keywords: Keywords HIV protease inhibitors ; lipodystrophy syndrome ; diabetes mellitus ; insulin resistance ; insulin signalling.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Patients treated with human immunodeficiency virus-1 protease inhibitors often develop impaired glucose tolerance or diabetes, most likely due to an induction of insulin resistance. We therefore investigated whether the protease inhibitor indinavir alters insulin signalling. Methods. We incubated HepG2 cells for 48 h without or with indinavir (100 μmol/l). Subsequently 125I-insulin binding to the cells and the effects of insulin stimulation on insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-Thr308-phosphorylation were measured. Results. In cells not exposed to indinavir, insulin (100 nmol/l) led to rapid increases of insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-phosphorylation during the first 75 s, followed by subsequent decreases. In indinavir-treated cells, these insulin-stimulated increases during the first 75 s were reduced by 30–60 % and this was not associated with alterations in cell number or viability, insulin binding to the cells or cellular insulin-receptor substrate-1-content. Conclusion/interpretation. Effects of indinavir on initial insulin signalling could cause, or contribute to, the metabolic effects of human immunodeficiency virus-1 protease inhibitors. [Diabetologia (2000) 43: 1145–1148]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051505
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  • 14
    Electronic Resource
    Electronic Resource
    Serum leptin concentrations throughout the menstrual cycle (2000)
    Springer
    Archives of gynecology and obstetrics 263 (2000), S. 99-101 
    Details
    ISSN: 1432-0711
    Keywords: Key words Leptin ; Menstrual cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Leptin is a cytokine involved in the regulation of food intake and fertility in rodents and in humans. No data exist about serum leptin serum levels during the spontaneous menstrual cycle. In this study 16 ovulatory cycles of endocrinologically normal volunteers were analyzed. Blood samples were taken on alternate days throughout the menstrual cycle for measurement of serum estradiol, progesterone, LH, FSH and leptin serum levels. No correlation of leptin values with estradiol values (r = 0.07) or progesterone values (r = 0.14) were seen. Mean leptin values during the luteal phase were significantly higher (16.67 ± 9.45 ng/mL) compared to the follicular phase (13.50 ± 8.75 ng/mL) (P 〈 0.02). A strongly positive correlation with the progression of the menstrual cycle could be seen (r = 0.91). The physiological significance of higher luteal phase leptin levels is unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004040050004
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  • 15
    Electronic Resource
    Electronic Resource
    Thrombelastographische Untersuchungen in vitro mit Heparin, Histamin, Serotonin, Protamin und Theophyllin-Nikotinat (1966)
    Springer
    Annals of hematology 13 (1966), S. 161-168 
    Details
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The influence of heparin, histamine, serotonin, theophylline-nicotinate (Complamin®), and protamine, as individual substances and combined, on blood coagulation was studied in vitro in the “Thrombelastograph”. Fibrinolysis could not be detected. Histamine, serotonin, and Complamin slightly reduce—without statistical confirmation—the r and c times as compared to untreated blood. A comparison of untreated blood with blood samples of the same donor with histamine, serotonin, and Complamin showed a reduction of the r time in all cases in the case of histamine, in 9 of 11 cases in the case of serotonin, and in 50% in the case of Complamin. Heparin and protamine as individual substances prolonged-statistically confirmed—the r and c times. The following combinations of pharmaceutical products reduced the shearing elasticity of the thrombus-statistically confirmed-partly by more than 50% compared with untreated blood: heparin, heparin-histamine-protamine II, heparin-histamine, heparin-Complamin-serotonin, heparin-histamine-serotonin heparin-Complamin-histamine, serotonin-protamine II. The heparin-neutralizing action of protamine could not be statistically confirmed at the dosages used in the pharmaca combinations heparin-Complamin-histamine-serotonin, heparin-Complamin, heparin-histamine.
    Notes: Zusammenfassung Im Thrombelastographen wurde in vitro der Einfluß von Heparin, Histamin, Serotonin, Theophyllin-Nikotinat (Complamin®) und Protamin, als Einzelsubstanzen und in Kombination miteinander, auf die Blutgerinnung untersucht. Eine Fibrinolyse konnte nicht erfaßt werden. Histamin, Serotonin und Complamin verkürzten geringgradig-ohne statistische Sicherung—die r- und k-Zeiten gegenüber Nativblut. Ein Vergleich zwischen nativen und mit Histamin, Serotonin und Complamin versetzten Blutproben desselben Spenders ergab jedoch für Histamin in allen, für Serotonin in 9 von 11 Fällen und für Complamin in der Hälfte der Fälle eine Verkürzung der r-Zeit. Heparin und Protamin, als Einzelsubstanzen, verlängerten-statistisch gesichert—die r- und k-Zeiten. Die Scherelastizität des Thrombus wurde durch folgende Pharmakakombinationen-statistisch gesichert-teilweise um mehr als die Hälfte gegenüber Nativblut herabgesetzt: Heparin, Heparin-Histamin-Protamin II, Heparin-Histamin, Heparin-Complamin-Serotonin, Heparin-Histamin-Serotonin, Heparin-Complamin-Histamin-Serotonin-Protamin II. Der heparinneutralisierende Effekt des Protamins konnte in den hier verwendeten Dosierungen in den Pharmakakombinationen Heparin-Complamin-Histamin-Serotonin, Heparin-Complamin, Heparin-Histamin statistich nicht gesichert werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01635453
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  • 16
    Electronic Resource
    Electronic Resource
    Zytochemische Untersuchungen an Zellen eines extramedullären Plasmozytoms des Magens (1967)
    Springer
    Annals of hematology 14 (1967), S. 211-216 
    Details
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Cytochemical examination of cells of an extramedullary plasmocytoma, of the stomach yielded large amounts of 1,2 glycol, acid mucopolysaccharides and glycogen, as well as small amounts of lipids and paramyloid. Furthermore, reactive NH2 groups and the amino acids cysteine and cystine, tyrosine and tryphophane were found to be present. The numerous multi-nuclei giant cells contained substantial amounts of these cytochemically established substances. There was striking proof of larger amounts of acid sulfogroup-free mucopolysaccharides. On the other hand, only sporadic protein coacervates in the form ofRussel bodies were found.
    Notes: Zusammenfassung Die zytochemischen Untersuchungen an Zellen eines extramedullären Plasmozytoms des Magens ergaben reichlich 1,2-Glykole, saure Mukopolysaccharide und Glykogen und geringe Mengen Lipide und Paramyloid. Weiterhin konnten reaktionsfähige NH2-Gruppen und die Aminosäuren Cystein, Cystin, Tyrosin und Tryptophan dargestellt werden. Die zahlreichen, mehrkernigen Riesenzellen enthielten besonders reichlich diese zytochemisch nachgewiesenen Substanzen. Auffallend war der Nachweis größerer Mengen saurer, sulfogruppenfreier Mukopolysaccharide. Dagegen konnten nur vereinzelt Eiweißkoazervate in FormRusselscher Körperchen gefunden werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01631636
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  • 17
    Electronic Resource
    Electronic Resource
    Autoradiographische und hämatologische Untersuchung zur Zellkinetik der Erythroblasten im Kurzzeitversuch nach doppelseitiger Nephrektomie und Ureterligatur bei Mäusen (1969)
    Springer
    Annals of hematology 19 (1969), S. 449-456 
    Details
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In this study the duration of the generation cycle as well as individual partial stages of the cell cycle of erythroblasts of mice were determined autoradiographically by means of the double labelling method in a short-term experiment under normal conditions as well as after bilateral ureteral ligature and bilateral nephrectomy. After nephrectomy but not after ureteral ligature the individual cell groups of erythroblasts showed a prolongation of the mean generation time and this was more than twofold. In contrast to this the DNA-synthesis time, which was approximately 8 hours, was approximately constant in the individual cell groups of erythroblasts as well in the individual test groups. These experiments show that for the prolongation of the mean generation time of erythroblasts, which has been observed after nephrectomy, obviously the deficiency of erythropoetin is of significant importance and not azotemia. By this model experiment in mice it might be possible to provide an explanation for the decrease of erythroblasts which has been observed in patients with acute renal failure.
    Notes: Zusammenfassung In der vorliegenden Arbeit wurde die Zeitdauer des Generationszyklus sowie einzelner Teilphasen des Zellzyklus für die Erythroblasten der Maus unter normalen Bedingungen sowie nach doppelseitiger Ureterligatur und doppelseitiger Nephrektomie mittels der Doppelmarkierungsmethode im Kurzzeitversuch autoradiographisch bestimmt. Es fand sich nach Nephrektomie, nicht dagegen nach Ureterligatur für die einzelnen Zellklassen der Erythroblasten eine Verlängerung der mittleren Generationszeit, und zwar um mehr als das Doppelte. Dagegen war die DNS-Synthesezeit mit einem Wert um 8 Std. sowohl bei den einzelnen Zellklassen der Erythroblasten wie bei den einzelnen Versuchsgruppen annähernd konstant. Die Versuche zeigen, daß für die nach Nephrektomie beobachtete Verlängerung der mittleren Generationszeit der Erythroblasten offenbar der Mangel an Erythropoetin und nicht die Azotämie von wesentlicher Bedeutung ist. Durch diesen Modellversuch an der Maus könnte der beim akuten Nierenversagen des Menschen beobachtete Erythroblastenschwund eine Erklärung finden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01631054
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  • 18
    Electronic Resource
    Electronic Resource
    Self-assembled monolayers of decanethiol on Au(111)/mica (2000)
    Springer
    The European physical journal 14 (2000), S. 371-376 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 61.16.Ch Scanning probe microscopy: scanning tunnelling, atomic force, scanning optical, magnetic force, etc. - 68.35.Bs Surface structure and topography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: We report here a preparation for thin gold films on mica substrates. We have investigated the influence of the substrate temperature and the evaporation rate on the morphology of the films. After careful outgasing of the substrate, 100 nm of Au is evaporated onto the mica surface maintained at high temperature. After slow cooling, ex situ characterizations are performed using AFM and STM. For our purposes, the best compromise between roughness and grain size is found to occur for an evaporation rate of 2 Ås-1 onto a mica substrate maintained at 460 C. We have used these substrates for STM and AFM study of decanethiol self-assembled monolayers (SAMs). We present results for gold samples immersed for a few seconds in decanethiol solutions, revealing an incomplete organization of the films. The organization process is discussed through comparison between AFM and STM data recorded on the SAMs. Then we present molecular resolution STM pictures of ordered SAMs for longer immersion times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100510050141
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  • 19
    Electronic Resource
    Electronic Resource
    Die klinische Lungentransplantation und ihre spezielle Problematik (1968)
    Springer
    Langenbeck's archives of surgery 322 (1968), S. 537-542 
    Details
    ISSN: 1435-2451
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über Homotransplantation der Lunge bei zwei jungen Patienten berichtet, bei denen eine pulmonale Insuffizienz bestand. Bei dem einen war die Lunge durch Salzsäuredämpfe zerstört, bei dem anderen war die pulmonale Insuffizienz durch Pneumonie bedingt. Es konnte zunächst eine Verbesserung der pulmonalen Funktion erreicht werden, aber, die unterschiedlichen Widerstände zwischen dem Transplantat und der eigenen verbliebenen Lunge führten zu einer Verteilungsstörung der Ventilation und Perfusion zwischen den beiden Lungen. Damit werden die klinischen Schwierigkeiten und Probleme der Ventilation nach der Transplantation demonstriert. Wir glauben, daß die getrennte künstliche Beatmung des Transplantates und der eigenen Lunge mit unterschiedlichen Beatmungsdrucken sowie die Blockierung der Pulmonalarterie, der eigenen Lunge mit einem Ballonkatheter die therapeutischen Konsequenzen darstellen könnten.
    Notes: Summary The authors report on homotransplantation of a lung in two young patients who suffered from pulmonary insufficiency. In one patient the lung was destroyed by hydrochloric acid vapors and in the other patient the pulmonary insufficiency was caused by pneumonia. Initially improvement of pulmonary function could be achieved but the different resistances between the transplanted organ and the patient's own remaining lung resulted in a distribution disorder of ventilation and perfusion between the two lungs. This demonstrates the clinical difficulties and problems of ventilation after transplantation. We believe that separate positive pressure ventilation of the transplant and of the patient's own lung with different ventilation pressures as well as blocking of the pulmonary artery of the patient's own lung with a ballooncatheter could be of therapeutic value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02453873
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  • 20
    Electronic Resource
    Electronic Resource
    Determination of fibrillatory frequency for assessment of the atrial electrophysiologic state in human atrial fibrillation – (2000)
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 11 (2000), S. 77-87 
    Details
    ISSN: 1435-1544
    Keywords: Schlüsselwörter Vorhofflimmern – Flimmerfrequenz –¶EKG-Signalverarbeitung – Elektrisches Remodeling ; Key words Atrial fibrillation – fibrillatory frequency –¶ECG signal processing – electrical remodeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Atrial fibrillation (AF) being the most common arrhythmia encountered in clinical practice is based on the continuous propagation of multiple wavelets wandering throughout the atria in most cases. Neither the natural history of AF nor its response to therapy are sufficiently predictable by clinical and echocardiographic parameters.¶   In contrast, invasively determined atrial fibrillatory frequency has been shown to be related with AF complexity, AF behavior and cardioversion success. Fibrillatory frequency can also be assessed from the surface ECG using digital signal processing (filtering, subtraction of averaged QRST complexes, and Fourier transformation). This measurement correlates well with intraatrial cycle length, a parameter which appears to have primary importance in the genesis and perpetuation of AF. Low frequency fibrillation is more likely to terminate spontaneously or to respond to antiarrhythmic therapy, while high frequency fibrillation is more often persistent and drug refractory. The influence of physiological and pharmaceutical interventions can be monitored directly.¶   Thus, determination of fibrillatory frequency from the surface ECG may prove useful for non-invasive assessment of the electrophysiologic state of the atria in patients with AF. Further studies are necessary to determine the role of this test in the management of AF.
    Notes: Zusammenfassung Vorhofflimmern (VHF) ist das elektrographische Bild mehrerer simultaner Kreiserregungen in den Vorhöfen. Weder der natürliche Verlauf von VHF noch die Effektivität therapeutischer Maßnahmen sind mit klinischen oder echokardiographischen Variablen vorhersagbar.¶   Im Gegensatz dazu konnten verschiedene Untersuchungen einen Zusammenhang zwischen invasiv ermittelter atrialer Flimmerfrequenz (atriale Zykluslänge) und VHF-Komplexität, klinischem Verhalten sowie Kardioversionserfolg feststellen. Die atriale Flimmerfrequenz kann ebenfalls aus dem Oberflächen-EKG mittels digitaler Signalverarbeitung (Filterung, Subtraktion gemittelter QRST-Komplexe, Fourie-Transformation) bestimmt werden. Die so erhaltene Frequenz korreliert hoch mit der invasiv ermittelten Frequenz. VHF mit niedriger Frequenz zeigt die Tendenz zur spontanen Termination und eine hohe Ansprechrate auf akute medikamentös-antiarrhythmische Therapie. Hingegen ist VHF mit hoher Frequenz eher persistierend und medikamenten-refraktär. Physiologische und pharmakologische Einflüsse auf die atriale Flimmerfrequenz können direkt beobachtet werden.¶   Die vorgestellte Methodik könnte somit zur Einschätzung des Krankheitsstadiums von VHF und damit dem gezielten Einsatz therapeutischer Optionen dienen. Weitere Studien müssen die Wertigkeit der atrialen Frequenzbestimmung aus dem Oberflächen-EKG im Management von VHF-Patienten zeigen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003990070042
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