Neuroreceptors and Ion Channels as Targets of Alcohol Narahashi, Toshio; Kuriyama, Kinya; Illes, P. ...
Alcoholism, clinical and experimental research,
20/May , Letnik:
25, Številka:
s1
Journal Article, Conference Proceeding
Recenzirano
This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Toshio Narahashi and Kinya Kuriyama. The presentations were (1) Modulation of ...neuroreceptors and ion channels by alcohol, by T. Narahashi; (2) Inhibition by ethanol of NMDA and AMPA receptor‐channels, by P. Illes, K. Wirkner, W. Fischer, K. Mühlberg, P. Scheibler, and C. Allgaier; (3) Effects of ethanol on metabotropic glutamate receptors, by K. Minami; (4) Acute alcohol actions on the 5‐HT3 ligand‐gated ion channel, by D. Lovinger; (5) Inhibition of NMDA receptors by MK801 attenuates ethanol‐induced taurine release from the hippocampus, by F. Lallemand, R.J. Ward, and P. DeWitte; and (6) Effect of ethanol on voltage‐operated Ca2+ channels in hepatic stellate cells, by T. Itatsu, Y. Takei, H. Oide, M. Hirose, X. E. Wang, S. Watanabe, M. Tateyama, R. Ochi, and N. Sato.
Background:
Although the detailed mechanism is unclear, zinc and its derivative, polaprezinc, have been reported to accelerate gastric ulcer healing in vivo.
Aim:
To investigate the detailed cellular ...mechanism of polaprezinc on gastric epithelial cells and fibroblasts with special attention to insulin‐like growth factor I (IGF‐I).
Methods:
Isolated rabbit gastric epithelial cells formed a complete monolayer, from which a circular artificial wound with constant size was made. The restoration process was monitored by measuring wound size up to 48 h. Either polaprezinc, IGF‐I, fibroblast conditioned medium or neutralized medium conditioned by anti‐IGF‐I antibody was added at the time of wounding. The expression of mRNA of IGF‐I, hepatocyte growth factor (HGF) and transforming growth factor α (TGF‐α) in fibroblasts with or without polaprezinc treatment was tested using reverse transcription polymerase chain reaction (RT‐PCR). Gastric epithelial cell proliferation was also examined by bromodeoxyuridine (BrdU) staining.
Results:
IGF‐I and fibroblast conditioned medium treatment accelerated gastric epithelial restoration which included cell migration and proliferation. However, polaprezinc and neutralized conditioned medium treatment did not accelerate epithelial repair. RT‐PCR for growth factor mRNA revealed the IGF‐I mRNA expression in fibroblasts was increased after treatment with polaprezinc.
Conclusion:
Polaprezinc induced IGF‐I production from mesenchymal cells, resulting in stimulation of epithelial cell restoration through a paracrine pathway. IGF‐I may play an important role in gastric wound repair.
BACKGROUND & AIMS: Growth factors play an important role in gastric wo und repair. The aim of this study was to assess the role of platelet- derived growth factor (PDGF) in gastric epithelial ...restoration. METHODS: PDGF-BB (1-50 ng/mL) was added to confluent cultures of rabbit gastric epithelial cells after wounding. Regrowth of the epithelial cells was monitored for 48 hours. The speed of cell migration was measured, and cell proliferation was detected by using a 5- bromodeoxyuridine (BrdU) staining technique. The labeling index was calculated for a 0.05-mm(2) area around the wound. RESULTS: After wounding, cells at the wound edge formed lamellipodia and showed ruffling movements. The addition of PDGF-BB significantly accelerated cell migration and proliferation as well as gastric restoration. Migration speed was 21 microm/h in control cultures and 32 microm/h and 40 microm/h in cultures containing 10 ng/mL and 50 ng/mL of PDGF-BB, respectively. In control cultures, BrdU-positive cells were rarely detected in the initial 24 hours after wounding, and maximum labeling occurred at 36 hours (labeling index, 3.4%). Cultures containing PDGF- BB showed maximum labeling at 24 hours (labeling index, 6.9%). CONCLUSIONS: PDGF-BB dose-dependently accelerated the migration rate and proliferation of cultured gastric epithelial cells after wounding. Therefore, PDGF-BB may play a role in gastric epithelial cell restoration during healing of gastric mucosal lesions. (Gastroenterology 1996 Mar;110(3):775-9)
Pixelated photon detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-pixel photon counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. We performed measurement of total noise ...rate, random noise rate, after-pulsing, crosstalk, and relative photon detection efficiency for a 1600px MPPC. The explosive increase of total noise rate to over-voltage is able to be understood of multiplication effect of after-pulsing and crosstalk. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are all able to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.
Pixelated Photon Detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-Pixel Photon Counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. Test of dark noise rate of a 1600 pixel ...MPPC as a function of over-voltage at room temperature indicates that the over-voltage is limited up to a few volts because of explosive increase of noise rate. The over-voltage dependence of random noise rate is nevertheless mostly linear. We confirmed this is due to multiplication effect of noises because of after-pulsing and crosstalk. Over-voltage dependence of random noise and photon detection efficiency are qualitatively different. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are possible to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.
The cross section and transverse single-spin asymmetries of μ- and μ+ from open heavy-flavor decays in polarized p+p collisions at s=200 GeV were measured by the PHENIX experiment during 2012 at the ...Relativistic Heavy Ion Collider. Because heavy-flavor production is dominated by gluon-gluon interactions at s=200 GeV, these measurements offer a unique opportunity to obtain information on the trigluon correlation functions. The measurements are performed at forward and backward rapidity (1.4<|y|<2.0) over the transverse momentum range of 1.25<pT<7 GeV/c for the cross section and 1.25<pT<5 GeV/c for the asymmetry measurements. The obtained cross section is compared to a fixed-order-plus-next-to-leading-log perturbative-quantum-chromodynamics calculation. The asymmetry results are consistent with zero within uncertainties, and a model calculation based on twist-3 three-gluon correlations agrees with the data.
A high S/N ratio spin flip chopper system for a pulsed neutron source Taketani, K.; Ebisawa, T.; Hino, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2011, Letnik:
634, Številka:
1
Journal Article
Recenzirano
We report a successful demonstration of a high S/N ratio spin flip chopper (SFC) system for pulsed neutron sources. The system consists of two SFCs and each SFC consists of a radio frequency (RF) ...flipper and Soller magnetic supermirrors. The aperture of the Soller mirror was 18mm in width and 20mm in height. The S/N ratio of the system was 306:1. This system is going to be installed to measure neutron lifetime precisely using the cold-neutron beam line, BL05 polarized-beam branch, at the Materials and Life Science Experimental Facility (MLF) in Japan Proton Accelerator Research Complex (J-PARC).
Summary
Background: Aspirin is known to cause adverse effects, including gastric mucosal injury, and to retard gastric wound healing. Growth factors including hepatocyte growth factor (HGF), ...epidermal growth factor (EGF) and insulin‐like growth factor‐I (IGF‐I) have been shown to play an important role in the repair of gastric mucosal injury.
Aim: To employ the cultured gastric epithelial cell model to elucidate the effects of aspirin, as well as several growth factors (HGF, EGF and IGF‐I), on gastric wound repair.
Methods: Isolated rabbit gastric epithelial cells (92% mucous cells) were cultured in F‐12 medium and formed a complete monolayer cell sheet in 48 h. A wound with a cell‐free area of constant size (2 mm
2) was then created and the wound repair process was monitored by measuring wound size every 12 h. Proliferating cells were detected by BrdU staining. Effects of aspirin (8 m
m), HGF (10 ng/mL), EGF (10 ng/mL) and IGF‐I (30 ng/mL) were assessed.
Results: Aspirin significantly retarded wound healing, but simultaneous addition of growth factors significantly accelerated wound repair compared with aspirin alone. Growth factors reversed the aspirin‐induced inhibition of cell proliferation.
Conclusion: Growth factors, including HGF, EGF and IGF‐I, reversed the aspirin‐induced inhibition of wound repair through their cytoprotective effects on gastric epithelial cells.
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