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  • 1
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 6907-6914 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: In a drift-tube analysis, an asymptotic solution for the transport of inter-reacting multiple ion swarms approaching to dynamic equilibrium is proposed. The solution describes a set of similar Gaussian profiles with two common "equilibrium'' transport coefficients. Although all the profiles apparently aggregate to the same location, there exists a slight peak difference between arbitrary two spectra. The difference holds even in the equilibrium. A generalized equilibrium constant is defined by the quotient of two reaction-frequency determinants. Those four kinetic constants are uniquely determined from the kinetic coefficients of all ion species without any influence of the initial conditions. The discrepancy between the thermal equilibrium and dynamic equilibrium is briefly discussed.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 88 (1966), S. 4267-4268 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 3664-3671 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Ion beam deceleration characteristics of a newly developed high-current, mass-separated, low-energy ion beam deposition system that utilizes an acceleration-deceleration method was studied. For realizing a high current ion beam of a mA level with energies down to 10 eV, the system developed is provided with a new ion beam deceleration system consisting of three cylindrical electrodes. Computer-simulated ion beam trajectory study indicates that ion beam convergence in the deceleration system required for suppressing the blowup of the ion beam due to the space charge effect depends on the electric potential distribution applied to these three electrodes. An Ar+ ion beam as high as 5.1 mA which is the highest ion current ever reported in the mass-separated, low-energy ion beam deposition system could be obtained at an ion energy of 100 eV under the optimum deceleration condition. Ion energy dependence of the Ar+ ion current at the target showing ion current decrease with the reduced ion energy was investigated utilizing a computer-simulated ion beam trajectory study. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1365-2826
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We have previously reported that voltage-dependent Ca2+ (VDC) channels of rat melanotrophs are inhibited by prostaglandin E2 (PGE2). In this study, mechanisms involved in the inhibitory actions of PGE2 receptors of rat melanotrophs were analysed using reverse transcriptase-polymerase chain reaction (RT-PCR), Ca2+-imaging and whole-cell, patch-clamp techniques with recently developed EP agonists, each of which is selective for the known four subclasses of EP receptors (EP1–4). PGE2 reversibly suppressed the cytosolic Ca2+ concentration ([Ca2+]i). The maximum reduction in [Ca2+]i by PGE2 was comparable to that by dopamine or to that by extracellular Ca2+ removal. RT-PCR analysis of all four EP receptors revealed that EP3 and EP4 receptor mRNAs were expressed in the intermediate lobe. The effects of PGE2 to suppress [Ca2+]i were mimicked by the selective EP3 agonist, ONO-AE-248, whereas three other EP agonists, ONO-DI-004 (EP1), ONO-AE1-259 (EP2) and ONO-AE1-329 (EP4), had little or no effect on [Ca2+]i. All four G-protein activated inward rectifying K+ (GIRK) channel mRNAs were identified in intermediate lobe tissues by RT-PCR. Dopamine concentration-dependently activated GIRK currents, whereas PGE2 did not activate GIRK currents, even at the concentration causing maximal inhibition of VDC channels. These results suggest that PGE2 acts on EP3 receptors to suppress Ca2+ entry of rat melanotrophs by selectively inhibiting VDC channels of these cells. We have compared the possible cellular and molecular mechanisms of inhibition by dopamine and PGE2.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Melbourne, Australia : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 26 (1999), S. 0 
    ISSN: 1440-1681
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: 1. The cell width of guinea-pig ventricular myocytes was measured using an optic device during patch-clamp experiments and the relationship between the ion channel flux and changes in cell volume was examined.2. On superfusing myocytes with 50, 70, 150 and 200% osmotic solutions, the relative cell width changed to 121.1 (n = 4), 110.8 (n = 27), 87.1 (n = 6) and 82.6% (n = 6) of control, respectively. Changes in cell length were less than 2% in these test solutions.3. The application of 300 nmol/L isoprenaline to myocytes swollen in the 70% hypotonic solution induced a decrease in cell width from 111.2 to 106.2% (n = 13). The application of isoprenaline in the isotonic solution also induced a decrease in cell width to 96.5% in eight of 13 cells. A membrane depolarization of 2–4 mV accompanied the isoprenaline-induced decrease in volume. In the remaining five cells, neither an obvious isoprenaline-induced decrease in volume nor membrane depolarization was observed. Under ruptured whole-cell voltage clamp conditions, the activation of inward isoprenaline-induced Cl− current decreased cell width.4. Cell width was seen to either decrease or increase when a large outward or inward K+ current, respectively, was induced by shifting the holding potential or by applying 200 μmol/L pinacidil. Under gramicidin-perforated whole-cell clamp conditions, the cell width did not change, even when a large inward K+ current was induced.5. When the test solution was applied to half of an elongated myocyte by using a micropipette, the cell width increased or decreased in the part exposed to the hypotonic or hypertonic test solutions, respectively. In contrast, in the other half of the elongated myocyte, the cell width responded in the opposite direction.6. It is concluded that a continuous ionic flux through ion channels is capable of inducing changes in cell volume by generating a localized osmotic gradient across the cardiac sarcolemma.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1546-1718
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] A new imprinted gene has been discovered in mice using the technique of restriction landmark genomic scanning (RGLS) with methylation sensitive enzymes. Eight out of 3,100 strain–specific Notl and BssHII spots were identified as imprinted in reciprocal F1 hybrids. Subsequently, we isolated a ...
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 14 (2000), S. 0 
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Aim: To examine the effects of beer, ethanol, peptone meal and combinations of either peptone meal and beer or peptone meal and ethanol on gastric acid secretion in vagally denervated pouch dogs. Methods and Results: The oral administration of either 200 mL of beer, 5% ethanol or 10% peptone meal significantly stimulated gastric acid secretion for 60–90 min in these dogs. With 5% ethanol the plasma gastrin concentration was not affected for 90 min. Combinations of 10% peptone and beer (peptone–beer) or 10% peptone and 5% ethanol (peptone–ethanol) potentiated the acid secretion and increased the plasma gastrin level. While a selective cholecystokinin-B/gastrin receptor antagonist, S-0509, had no effect on ethanol-stimulated acid secretion, the compound markedly inhibited both peptone–beer-stimulated and peptone–ethanol-stimulated gastric acid secretion. Famotidine and atropine significantly inhibited gastric acid secretion stimulated by 5% ethanol, peptone–beer and peptone–ethanol. Conclusions: The mechanisms by which peptone–beer and peptone–ethanol stimulate gastric acid secretion may be mediated not only by increased plasma gastrin, but also by the action of histamine and acetylcholine coupled with the increased plasma gastrin. Ethanol-stimulated secretion appears to be unrelated to circulating gastrin, yet may be related to the acid regulatory mechanism involving histamine and acetylcholine.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Several studies have shown that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection, promoting the development of atrophic gastritis.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To study the effects of long-term use of antisecretory agents on the H. pylori-positive gastric mucosa in Japan, a country with a high incidence of gastric cancer.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:A total of 141 H. pylori-positive patients who had peptic ulcers or reflux oesophagitis were treated for 3 years with either omeprazole (20 mg/day) alone (n=7) or with omeprazole for primary therapy (8 weeks), followed by famotidine (40 mg/day) for maintenance therapy (n=134). Endoscopy was performed before, during, and after treatment. Biopsy specimens were taken from the greater curvature of the antrum and corpus and were examined histologically.〈section xml:id="abs1-4"〉〈title type="main"〉Results:The long-term use of famotidine after 8 weeks of treatment with omeprazole distinctly decreased H. pylori density and neutrophil infiltration in the antrum, but did not change H. pylori density in the corpus. The gastritis score increased in patients who had no, or only mild corpus gastritis before treatment (n=74), and significantly decreased in those who had moderate or severe gastritis before treatment (n=60). In four of the seven patients who received long-term treatment with omeprazole alone, neutrophil infiltration and H. pylori density decreased not only in the antrum but also in the corpus. There was no increase in intestinal metaplasia or mucosal atrophy as assessed endoscopically during follow-up.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusion:Changes in corpus gastritis in response to acid-suppressive therapy depend on the severity of gastritis before treatment. Long-term use of acid-suppressive therapy apparently does not accelerate the development of atrophy or intestinal metaplasia in Japanese patients.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background: The purpose of the present study was to examine the association between interleukin-8 (IL-8) in the gastric body due to Helicobacter pylori infection and histological gastritis, as well as elucidating the effect of acid secretion inhibitors on H. pylori associated body gastritis in duodenal ulcer patients. Methods: Twenty H. pylori-negative patients, 20 H. pylori-positive patients with chronic gastritis without peptic ulceration, and 20 H. pylori-positive duodenal ulcer patients (DU) were studied. Four biopsy samples were taken, each from the greater curvature of the antrum and body of the stomach. Biopsies were histologically investigated by ELISA to determine the density of H. pylori, the degree of neutrophil infiltration and the IL-8 concentration in the mucosa. Results: In the gastric mucosa of H. pylori-negative subjects, no IL-8 and hardly any neutrophil infiltration were observed. In contrast, enhanced IL-8 production and increased neutrophil infiltration were present in those infected with H. pylori. In H. pylori-positive patients, a significant correlation was observed between the IL-8 concentration and the degree of neutrophil infiltration, but no correlation was found in the body mucosa of those with DU. Twelve of 20 DU patients demonstrated hardly any neutrophil infiltration, despite the increased mucosal IL-8 content in the body. The administration of omeprazole in DU patients markedly increased mucosal neutrophil infiltration even though it did not cause any significant change in the H. pylori density and IL-8 concentration in the body. Although the effect of omeprazole was transient, a significant increase in neutrophil infiltration continued in comparison with the status before omeprazole administration in those subsequently undergoing maintenance treatment with H2-blockers. Conclusion: In H. pylori-positive chronic gastritis, IL-8 concentration is enhanced in the mucosa of the body, and is associated with increased neutrophil infiltration. However, in DU patients, despite increases in body IL-8 concentration, neutrophil infiltration is reduced and the gastritis may be localized in the antrum.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 115 (1983), S. 456-462 
    ISSN: 0006-291X
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
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