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  • 1
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Transforming growth factor-β1 (TGF-β1) is generally considered to play an important role in the pathogenesis of chronic inflammation and fibrosis.Objective and methods This study was designed to determine mechanisms of reduced responsiveness of guinea-pig tracheal smooth muscle to β-adrenoceptor agonists by TGF-β1, using isometric tension records and tissue cAMP measurement. Moreover, we examined the involvement of the signal transduction processes of TGF-β superfamily in the desensitization of β-adrenoceptors.Results After exposure to 0.2–2000 pm TGF-β1 for 4–8 h, the inhibitory effects of 1 µm isoprenaline (ISO) and 10 µm forskolin on 1 µm MCh-induced contraction were markedly reduced in a concentration-dependent fashion. The desensitization by TGF-β1 was greater against ISO than for forskolin. The values of EC75 for the curves for ISO after exposure to the normal bathing solution and TGF-β1 were 0.039 ± 0.02 and 0.38 ± 0.28 µm, respectively. The values of EC50 for the curves for forskolin under these conditions were 0.50 ± 0.12 and 0.89 ± 0.21 µm, respectively. On the other hand, the inhibitory effects of phosphodiesterase inhibitors such as theophylline and rolipram were not attenuated after exposure to TGF-β1. Concentration–inhibition curve for ISO was shifted to the right after exposure to 2000 pm TGF-β1 for 8 h more than that curve for forskolin. In contrast, the curve for theophylline was not shifted to the right by TGF-β1. When the tissues were incubated with TGF-β1 in the presence of IFN-γ, an intracellular antagonist of TGF-β signalling, IFN-γ inhibited the reduced response to ISO and forskolin after exposure to TGF-β1 in a concentration-dependent fashion. After exposure to TGF-β1, the effects of cAMP accumulation of ISO was significantly reduced, however, neither forskolin-nor theophylline-induced cAMP accumulation was affected. IFN-γ had no significant effect on cAMP accumulation either to ISO or forskolin.Conclusions Impairment of the β-adrenoceptors/adenylyl cyclase pathway are involved in heterologous desensitization of β-adrenoceptors induced by TGF-β1 in airway smooth muscle. IFN-γ functionally suppresses this phenomenon via cAMP-independent processes. Phosphodiesterase is still intact under this condition.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 2330-2332 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Low-temperature processing for high-performance solar cells based on hydrogenated microcrystalline silicon (μc-Si:H) has been developed using a conventional rf plasma-enhanced chemical vapor deposition (PECVD) technique at an excitation frequency of 13.56 MHz under a high deposition pressure condition. Among pin type solar cells, it is found that deposition temperature of i-layer at 140 °C is effective particularly for improving open circuit voltage (Voc), surprisingly without deteriorating short circuit current or fill factor. Carrier density of undoped μc-Si abruptly decreases for deposition temperatures lower than 180 °C, and the improvement of Voc is ascribed to a decrease of shunt leakage current arising from the oxygen-related donors. This implies that oxygen-related donors can be passivated at low deposition temperatures and that hydrogen plays an important role for the passivation. We propose a simple model for the hydrogen passivation of oxygen related donors. We apply this passivation technique to solar cells, and consequently a conversion efficiency of 8.9% (Voc=0.51 V, Jsc=25 mA/cm−1, FF=0.70) has been obtained in spite of an oxygen concentration of 2×1019 cm−3 in combination with device optimization such as a p-layer. Effect of deposition temperature of i-layer upon other solar cell parameter, short circuit current, and fill factor is also discussed. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Neutrophil–endothelial cell interactions mediated by adhesion molecules may be involved in gastric mucosal inflammation associated with Helicobacter pylori or nonsteroidal anti-inflammatory drugs. Aim: To investigate the effects of proton pump inhibitors and histamine-2 receptor antagonists (HRA) on neutrophil-endothelial cell adhesive interactions induced by H. pylori water extract (HPE) or interleukin-1β (IL-1β). Methods: Human peripheral neutrophils and umbilical vein endothelial cells were incubated with either proton pump inhibitors (lansoprazole and omeprazole) or HRA (famotidine and ranitidine). Neutrophil surface expression of CD11b and CD18 and endothelial cell intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) were assessed by flow cytometry and an enzyme immunoassay, respectively. Neutrophil adherence was defined as the ratio of exogenous neutrophils that adhered to the endothelial monolayers. Results: The expression of CD11b and CD18 on neutrophils and neutrophil-dependent adhesion to endothelial cells elicited by HPE were inhibited by lansoprazole and omeprazole at clinical relevant doses, and the expression of ICAM-1 and VCAM-1 on endothelial cells and endothelial-dependent neutrophil adherence induced by IL-1β were also inhibited by lansoprazole and omeprazole at similar doses. Famotidine and ranitidine had no effect on neutrophil–endothelial cell interactions. Conclusions: These results indicate that proton pump inhibitors can attenuate neutrophil adherence to endothelial cells via inhibiting the expression of adhesion molecules, suggesting that proton pump inhibitors may have anti-inflammatory activity.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Nitric oxide synthase activity is increased in the stomach in association with Helicobacter pylori infection and portal hypertension, but the mechanism by which nitric oxide contributes to mucosal damage remains unclear. Aim: To examine whether nitric oxide injures gastric mucosal cells and whether cellular glutathione affects nitric oxide-induced cytotoxicity. Methods: A confluent monolayer of RGM-1 gastric mucosal cells was exposed to nitric oxide donors (NOC5 or NOC12). Cell viability was determined by trypan blue dye exclusion, lactate dehydrogenase release and supravital staining with Hoechst 33342 and propidium iodide. The kinetics of the reduced/oxidized forms of glutathione were also measured, as well as the effect of glutathione-depletion or glutathione-precursor treatment on nitric oxide-induced cytotoxicity. Results: Excess exogenous nitric oxide produced by NOC5 or NOC12 induced necrosis in RGM-1 cells in a time- and concentration-dependent manner. The level of reduced glutathione drastically decreased prior to the loss of cell viability and remained low, but oxidized glutathione was not affected. Glutathione depletion increased necrosis of both NOCs in an NOC-concentration-related fashion, while pre-treatment with γ-glutamylcysteine ethyl ester reduced their necrotic susceptibility. Conclusion: Exogenous nitric oxide induced necrosis in gastric mucosal cells, and intracellular reduced glutathione protects gastric mucosal cells from damage by nitric oxide.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1439-7609
    Keywords: Key words Radiograph ; Rheumatoid arthritis ; Bone volume ; NIH Image ; Computer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We attempted to quantify periarticular bone atrophy from radiographs of the proximal phalanx in patients with rheumatoid arthritis (RA) by means of the National Institutes of Health (NIH) Image computer program. The degree of brightness or darkness in four squares, each 20 × 20 pixels, in the right third proximal phalanx was measured using NIH Image, and the mean value of the 400 pixels was defined as the brightness/darkness index (BDI). The BDI was used to express bone volume. The BDI value was set at zero for an area of complete darkness and at 255 for an area of maximum brightness. The mean coefficient of variation in our hospital was 2.28%. The BDI was measured in 54 RA patients and 146 normal volunteers. The mean BDI at the midpoint of the diaphysis was 100 in RA patients and 176 in normal volunteers, while at the medial side of the proximal end it was 75 and 145, respectively. The difference between normal volunteers and RA patients was greatest in younger people. In some young RA patients, the BDI was significantly low at the medial side of the proximal end, clearly demonstrating periarticular bone atrophy. Periarticular bone atrophy can be quantified using the NIH Image computer program.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0584
    Keywords: Aggressive-phase multiple myeloma ; Burkitt's type translocation ; Double-color fluorescence in situ hybridization ; c-myc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-232X
    Keywords: Key words Acute intermittent porphyria (AIP) ; Gene analysis ; Hydroxymethylbilane synthase (HMBS) ; Molecular pathology ; Mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease caused by a decreased activity of hydroxymethylbilane synthase (HMBS). Regarding the abnormalities of the HMBS gene, many different mutations have been reported worldwide; however, few families from Japan have been studied. In this work, we investigated the presence of mutations in two unrelated Japanese patients with AIP. Mutational analysis was performed using the polymerase chain reaction-single strand conformation polymorphism (SSCP) method, followed by DNA sequencing. Reliable restriction enzyme cleavage assays were also established for the pedigree analyses. Unique SSCP patterns were noted in exons 12 and 15 of the HMBS gene. Sequencing revealed different mutations in each patient: a two-base deletion of CT at nucleotide 730–731 (730delCT), and also a two-base deletion of CA at position 982–983 (982delCA). Both of the deletion mutations lead to truncated proteins with an abnormal C-terminus, which would be expected to decrease the stability and/or activity of HMBS. Using the cleavage assays, we were able to definitively identify gene carriers in the family. This study adds a novel mutation to those that have been previously reported, and emphasizes that molecular analysis would be very useful not only for the identification of asymptomatic gene carriers in the family but also for the detection of ancestral founders in porphyria families.
    Type of Medium: Electronic Resource
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