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  • 1
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    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
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  • 3
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 50 (1990), S. 13-17 
    ISSN: 1432-0649
    Keywords: 32.80P
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract 172Yb+ ions in an rf trap have been laser cooled for the first time by driving the 2 S 1/2–2 P 1/2 transition at 369.5 nm. It was necessary to irradiate the ions with 2.438 μm infra-red radiation to depopulate the metastable 2 D 3/2 state. An upper limit on ion energies was determined by observing the size of the trapped cloud and corresponds to a temperature below 2 K. Cooled ion lineshapes were compared with simulations and coherence nulls were observed in the infra-red frequency scans.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 263 (2000), S. 99-101 
    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
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  • 6
    ISSN: 0942-0940
    Keywords: Intraoperative ultrasound ; craniotomy ; cerebral convexity ; brain neoplasms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The authors describe a method of real-time ultrasound-guided craniotomy for an approach to cerebral convexity lesions. During surgery, a specially designed high frequency (7.5 MHz) sector probe with a thin (11 mm), extended tip is used to image the cerebral lesion through a single burr-hole. The distance between burr-hole and lesion and the direction of the target are then determined from the ultrasound images, and craniotomy is completed with the aid of these parameters. Errors in the preoperative planning of the approach, which might result in incorrect placement of the craniotomy, can easily be recognized and corrected at an early stage of the operation, before the craniotomy has been completed. This technique greatly improves the accuracy in placing craniotomy flaps. Since the risk of misplacing the craniotomy is virtually eliminated in lesions which are identifiable on ultrasound images, the technique allows the surgeon to keep the skull opening as limited as possible.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 91-93 (Jan. 1992), p. 35-40 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 595 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 836-838 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: For the International Fusion Materials Irradiation Facility (IFMIF) scenario, a 140 mA deuterium beam in continuous wave (cw) mode with an atomic yield of above 85% is required. The normalized root-mean-square emittance should be less than 0.2 π mm mrad at the entrance of a RFQ. As part of a conceptual design for IFMIF, a new ion source has been developed and is tested at the Institut für Angewandte Physik in Frankfurt. The ion source is of the volume type with a tungsten cathode driving the discharge. Both cw and pulsed mode are possible and were studied. First experiments were carried out with deuterium. 80 mA deuterons with a D+ fraction of above 90% were extracted [A. Maser et al., Rev. Sci. Instrum. 67, 1054 (1996)]. In order to avoid neutron generation by the d–d reaction, hydrogen was used instead of deuterium later on. As far as the ion source and plasma production processes are concerned, the use of hydrogen instead of deuterium is equivalent because of their similar atomic shells. Recently, a 200 mA proton beam at 55 kV was extracted in cw mode (according to Child–Langmuir, 200 mA H+ corresponds to 140 mA D+) with a H+ fraction of 93%. This article will give a detailed description of the ion source and the essential experimental results. Especially, the influence of important physical parameters (such as discharge current and strength of the filter field) on the H+ fraction was studied. By using different kinds of auxiliary gases, the influence on the H+ fraction and the noise level were investigated, too. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 758-759 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Results of experiments, carried out in space and on earth, are reported in which spinodal decomposition in a single-component fluid (SF6) is studied by small angle light scattering. Deformed circular light-scattering patterns are observed. They reflect deformation of density fluctuations by gravity effects and shear flow.
    Type of Medium: Electronic Resource
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