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  • 1
    Electronic Resource
    Electronic Resource
    A spatially scanning vacuum ultraviolet and visible range spectrometer for spectroscopy of tokamak plasmas in ASDEX-Upgrade (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 5433-5441 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A spatially scanning, combined vacuum-ultraviolet (VUV) and visible range spectrometer system for the spectroscopy of tokamak plasmas in the ASDEX-Upgrade experiment is described. This system is designed to allow flexible observation of about 2/3 of the boundary plasma using VUV (30–200 nm) and visible range spectrometers viewing along a common line of sight which can be scanned during the plasma discharge by means of a rotatable mirror. From successive spectra recorded using intensified, multichannel photodiode detectors and the recorded position data, spatial profiles of the plasma emission can be reconstructed. Because radiation losses from the boundary plasma can largely be attributed to line emission in the VUV spectral region, this instrument finds application in quantitative studies of radiation loss processes as well as to studies of impurity production and transport. Simultaneous observation in the visible spectral range facilitates an in situ absolute calibration of the VUV instrument by means of the "branching-ratios'' technique. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146065
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative analysis of the effects of flavonoids on proliferation, cytotoxicity, and apoptosis in human colon cancer cell lines (1999)
    Springer
    European journal of nutrition 38 (1999), S. 133-142 
    Details
    ISSN: 1436-6215
    Keywords: Key words Flavonoids – cancer-cell lines – proliferation –, cytotoxicity – apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Notes: Summary Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Their proposed protective role in tumor development may prevail especially in the intestinal tract due to direct exposure of intestinal epithelia to these dietary ingredients. We have screened more than 30 flavonoids for their effects on cell proliferation and potential cytotoxicity in the human colon cancer cell lines Caco-2, displaying features of small intestinal epithelial cells, and HT-29, resembling colonic crypt cells. In addition, for selected compounds we assessed whether they induce apoptosis by determining caspase-3 activation. Studies on the dose dependent effects of the flavonoids showed antiproliferative activity of all compounds with EC50 values ranging between 39.7 ± 2.3 μM (baicalein) and 203.6 ± 15.5 μM (diosmin). In almost all cases, growth inhibition by the flavonoids occured in the absence of cytotoxicity. There was no obvious structure-activity relationship in the antiproliferative effects either on basis of the subclasses (i.e., isoflavones, flavones, flavonols, flavanones) or with respect to kind or position of substituents within a class. In a subset of experiments we examined the antiproliferative activities of the most potent compound of each flavonoid subgroup in addition in LLC-PK1, a renal tubular cell line, and the human breast cancer cell line MCF-7. Out of four flavonols tested, three displayed almost equal antiproliferative activities in all cell lines but fisetin was less potent in MCF-7 cells. The flavanones bavachinin and flavanone inhibited growth of Caco-2 and HT-29 cells with lower EC50 values than that obtained in LLC-PK1 and MCF-7 cells. The lower susceptibility of LLC-PK1 and MCF-7 cells towards growth arrest was even more pronounced in the case of the flavone baicalein. Half maximal growth-inhibition in LLC-PK1 and MCF-7 required 2.5 and 6.6 fold higher concentrations than that needed in the intestinal cell lines. The flavonoids failed to affect apoptosis in LLC-PK1 and MCF-7, whereas baicalein and myricetin were able to induce apoptosis in HT-29 and Caco-2 cells. In conclusion, flavonoids of the flavone, flavonol, flavanone, and isoflavone classes possess antiproliferative effects in different cancer cell lines. The capability of flavonoids for growth inhibition and induction of apoptosis can not be predicted on the basis of their chemical composition and structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003940050054
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  • 3
    Electronic Resource
    Electronic Resource
    Angiotensin converting-enzyme inhibitor treatment reduces glomerular p16INK4 and p27Kip1 expression in diabetic BBdp rats (1999)
    Springer
    Diabetologia 42 (1999), S. 1425-1432 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Diabetic nephropathy, cyclin-dependent kinase inhibitors, glomerular hypertrophy, cell cycle arrest, angiotensin II, progression of renal failure.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Renal hypertrophy occurs early in diabetes mellitus and precedes the development of glomerulosclerosis and tubulointerstitial fibrosis. We have previously shown that cultured mesangial cells exposed to high glucose are arrested in the G1-phase of the cell cycle and undergo cellular hypertrophy. High glucose-mediated induction of p27Kip1, an inhibitor of cyclin-dependent kinases, is essential in this process. Further investigations have also shown that p27Kip1 and p21Cip1, other cyclin-dependent kinase inhibitors, are up regulated in the kidneys of mice with Type I (insulin-dependent) as well as Type II (non-insulin-dependent) diabetes mellitus. Our study was undertaken to test a potential effect of short-term treatment with the angiotensin-converting enzyme inhibitor enalapril on the glomerular expression of the cyclin-dependent kinase inhibitors p16INK4, p21Cip1, and p27Kip1 in BBdp rats, an autoimmune model of Type I diabetes.¶Methods. We evaluated p16INK4, p21Cip1, and p27Kip1 protein expression in isolated glomeruli by western blots. We also assessed p27Kip1 positive glomerular cells by immunohistochemistry.¶Results. Glomerular expression of all three cyclin-dependent kinase inhibitors were stimulated in BBdp rats compared with non-diabetic BBdr animals. Enalapril treatment for 3 weeks, started after the onset of diabetes, reduced the glomerular expression of p16INK4 and p27Kip1 but not of p21Cip1. Enalapril also prevented the increase in kidney weights observed in BBdp rats but had no effect on systolic blood pressure or glucose concentrations.¶Conclusion/interpretation. Our data show that enalapril attenuates the glomerular expression of cyclin-dependent kinase inhibitors in diabetes and suggest a molecular mechanism of how angiotensin-converting enzyme inhibitors prevent renal hypertrophy in diabetes. [Diabetologia (1999) 42: 1425–1432]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051314
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  • 4
    Electronic Resource
    Electronic Resource
    Eine 73jährige Patientin mit hypertensiver Krise War der Einsatz des Kalziumantagonisten Nifedipin gerechtfertigt? (1999)
    Springer
    Der Internist 40 (1999), S. 205-209 
    Details
    ISSN: 1432-1289
    Keywords: Schlüsselwörter Nifedipin ; Kalziumantagonisten ; Koronare Herzkrankheit ; Hypertensive Krise ; Hypertensive Dringlichkeit ; Evidence Based Medicine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Eine 73jährige Patientin erwachte in der Nacht mit linksthorakalen Schmerzen und Herzklopfen. Der herbeigerufene Notarzt diagnostizierte eine hypertensive Krise. Der Blutdruck war 260/120 mm Hg, und der Notarzt verabreichte 50 mg Urapidil i.v.. Es folgte der Transport in die Klinik. In der Notaufnahme war der Blutdruck mit 190/120 mm Hg weiterhin erhöht. Die Patientin war beschwerdefrei. Das EKG zeigte keine Ischämie-typischen oder Infarkt-verdächtigen Veränderungen. Nach Gabe von 10 mg Nifedipin als Kapsel kam es zum schnellen Abfall des Blutdrucks auf 120/80 mm Hg. Es entwickelte sich eine Tachykardie, und heftige linksthorakale Schmerzen traten auf. Das EKG zeigte eine Sinustachykardie mit Ischämie-typischen ST-Streckensenkungen von 0.3 mV in den Brustwandableitungen. Die Symptomatik besserte sich nach i.v. Gabe von Nitroglycerin und Frequenzkontrolle. Das 12 h später geschriebene EKG zeigte keine Ischämie-typischen Veränderungen. Nach Intensivierung der antihypertensiven Therapie wurde die Patientin beschwerdefrei entlassen. Bei der Patientin waren durch die Gabe von Nifedipin Angina pectoris Beschwerden und ischämietypische EKG-Veränderungen ausgelöst worden. Wir diskutieren, warum wir trotz dieser Beobachtung den Gebrauch von Nifedipinkapseln bei der hypertensiven Krise für gerechtfertigt halten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001080050325
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison of different methods for dead space measurements in ventilated newborns using CO2-volume plot (1999)
    Springer
    Intensive care medicine 25 (1999), S. 705-713 
    Details
    ISSN: 1432-1238
    Keywords: Key words Respiratory dead space ; Carbon dioxide ; Lung function testing ; Mechanical ventilation ; Newborn ; Single breath test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: The aim of the study was to test the applicability of Ventrak 1550/Capnogard 1265 (V-C) for respiratory dead space (Vd) measurement and to determine anatomic (VDana), physiologic (VDphys), and alveolar dead spaces (VDalv) in ventilated neonates. Design: Prospective study. Setting: Neonatal intensive care unit. Patients: 33 investigations in 22 ventilated neonates; median gestational age 34.5 weeks (range 27–41), median birthweight 2658 g (range 790–3940). Method: The single-breath CO2 test (SBT-CO2) and transcutaneous partial pressure of carbon dioxide (PCO2) were recorded simultaneously and Vd was determined (1) automatically (V-C software), (2) by interactive analysis of the PCO2 volume plot, and (3) manually by Bohr/Enghoff equations using data obtained by V-C. Results: Vd measurements were possible in all cases by method 3 but not possible by methods 1 and 2 in 22 of 33 investigations (67 %), especially in preterm neonates, because of disturbed signals. VDana/kg (1.6 ± 0.6 ml/kg, mean ± SD), VDana/tidal volume (Vt) (0.36 ± 0.09) were lower compared to published data in spontaneously breathing infants, whereas VDphys/kg (2.3 ± 0.9 ml/kg) and VDphys/Vt (0.50 ± 0.12) are comparable to data obtained from the literature. Five minutes after insertion of the sensor (dead space 2.6 ml) into the ventilatory circuit, the transcutaneous PCO2 rose above baseline for 3.2 % (patients 〉 2500 g) and 5.7 % (patients 〈 2500 g). The time necessary for one analysis was 50–60 min. Conclusion: In ventilated newborns, dead space measurements were possible only in one-third by SBT-CO2, but in all cases by Bohr/Enghoff equations. Improved software could further reduce the time needed for one analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001340050933
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  • 6
    Electronic Resource
    Electronic Resource
    Transport of Charged Dipeptides by the Intestinal H+/Peptide Symporter PepT1 Expressed in Xenopus laevis Oocytes (1997)
    Springer
    The journal of membrane biology 155 (1997), S. 247 -256 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Intestinal peptide transporter — Expression — Substrate specificity — Two-electrode voltage-clamp technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. The cloned intestinal peptide transporter is capable of electrogenic H+-coupled cotransport of neutral di- and tripeptides and selected peptide mimetics. Since the mechanism by which PepT1 transports substrates that carry a net negative or positive charge at neutral pH is poorly understood, we determined in Xenopus oocytes expressing PepT1 the characteristics of transport of differently charged glycylpeptides. Transport function of PepT1 was assessed by flux studies employing a radiolabeled dipeptide and by the two-electrode voltage-clamp-technique. Our studies show, that the transporter is capable of translocating all substrates by an electrogenic process that follows Michaelis Menten kinetics. Whereas the apparent K0.5 value of a zwitterionic substrate is only moderately affected by alterations in pH or membrane potential, K0.5 values of charged substrates are strongly dependent on both, pH and membrane potential. Whereas the affinity of the anionic dipeptide increased dramatically by lowering the pH, a cationic substrate shows only a weak affinity for PepT1 at all pH values (5.5–8.0). The driving force for uptake is provided mainly by the inside negative transmembrane electrical potential. In addition, affinity for proton interaction with PepT1 was found to depend on membrane potential and proton binding subsequently affects the substrate affinity. Furthermore, our studies suggest, that uptake of the zwitterionic form of a charged substrate contributes to overall transport and that consequently the stoichiometry of the flux-coupling ratios for peptide: H+/H3O+ cotransport may vary depending on pH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900177
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  • 7
    Electronic Resource
    Electronic Resource
    On-line scintillation counting on MeltilexTM basis (1996)
    Springer
    Journal of radioanalytical and nuclear chemistry 203 (1996), S. 87-96 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A detection system is described for monitoring on-line radioactive process solutions by solid scintillation counting. The system consists of a flow cell with perspex windows coated with the plastic scintillator MeltilexTM. The cell is confined in a chamber welded to a La Calhène container. Thus the detection device is easily attached to, detached from and transported between glove boxes, and the electronic parts and the multiplers can be kept outside the box containment. Using outside coated windows, the detector responds to γ radiation, using inside coated windows, α and β particles can be detected. Selective measurements can be carried out by installing a chromatographic column in the detector loop. The detection limits of the cell for Am amount to 4·10−9 g Am/ml for outside coated windows and 10−9 g Am/ml for inside coated windows. windows and 10−9 g Am/ml for inside coated windows.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02060383
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