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141.
The oxygenation reactions of two catecholatoiron(III) complexes, [Fe(TPA)(3,5-di-tert-butylcatecholate)]BPh4 (1) and [Fe(TPA)(4-chlorocatecholate)]BPh4 (2) (TPA = tris(pyridin-2-ylmethyl)amine), with O2 have been investigated by means of ESI-MS spectrometry to elucidate the detailed mechanisms of oxygen atom insertion from O2 into the catecholate ligands promoted by iron(III) complexes. Both 1 and 2 gave products formed by incorporation of two oxygen atoms into the catecholate ligands; 2,4-di-tert-butylmuconolactone for 1 and cis-dienelactone for 2. ESI-MS spectra of the products formed by the reaction with 18O2 revealed the following points: (1) Two oxygen atoms of 2,4-di-tert-butylmuconolactone are mostly derived from 18O2. (2) cis-Dienelactone is obtained as a mixture of mono- and double-18O-labeled species with a ratio of 50:50. These results suggest that the second oxygen atom is incorporated into muconic anhydride through nucleophilic attack on the carbonyl groups of muconic anhydride by the 18O-oxo-group of the metal center, and that this process competes with dissociation of muconic anhydride from the metal center. 相似文献
142.
Ito S Sawada M Haneda M Fujii S Oh-Hashi K Kiuchi K Takahashi M Isobe K 《FEBS letters》2005,579(9):1995-2000
Alzheimer's disease is characterized by numerous amyloid-beta peptide (Abeta) plaques surrounded by microglia. Here we report that Abeta induces the proliferation of the mouse microglial cell line Ra2 by increasing the expression of macrophage colony-stimulating factor (M-CSF). We examined signal cascades for Abeta-induced M-CSF mRNA expression. The induction of M-CSF was blocked by a phosphatidylinositol 3 kinase (PI3-kinase) inhibitor (LY294002), a Src family tyrosine kinase inhibitor (PP1) and an Akt inhibitor. Electrophoretic mobility shift assays showed that Abeta enhanced NF-kappaB binding activity to the NF-kappaB site of the mouse M-CSF promoter, which was blocked by LY294002. These results indicate that Abeta induces M-CSF mRNA expression via the PI3-kinase/Akt/NF-kappaB pathway. 相似文献
143.
Kanazawa J Ohta S Shitara K Fujita F Fujita M Hanai N Akinaga S Okabe M 《Cancer immunology, immunotherapy : CII》2000,49(4-5):253-258
KM871 is a chimeric antibody recognizing ganglioside GD3, which is one of the major gangliosides expressed on the cell surface
of human tumors of neuroectodermal origin. This study demonstrates the antitumor activity of KM871 against human melanoma
xenografts in nude mice, and analyzes the effector function operating in mice. In a well-established tumor model, KM871 showed
antitumor activity against H-15 and SK-MEL-28 human melanoma but not against H-187 and G361 human melanoma when administered
intravenously 5 days/week for 2 weeks. The G361 tumor became sensitive when KM871 was first administered on the day of tumor
inoculation. In this assay, it was observed that almost all the mice were tumor-free, but a few mice developed tumors. Therefore,
we examined the amount and expression pattern of GD3 antigen on G361 tumors escaping from KM871 treatment, but no change was
observed. Next we examined the optimal administration schedule for KM871 in mice, using H-15 melanoma. KM871 showed antitumor
activity when administered intravenously either 5 days/week for 2 weeks or three biweekly doses. However, the effect of the
former schedule was stronger than three biweekly doses. To compare the effector function in humans and mice, we studied the
complement-mediated cytotoxicity, antibody-dependent cell-mediated cytotoxicity and antibody-dependent macrophage-mediated
cytotoxicity of KM871 using complement or effector cells prepared from humans and mice. It was found that the antibody-dependent
cell-mediated cytotoxicity exerted by polymorphonuclear cells and antibody-dependent macrophage-mediated cytotoxicity were
the only antitumor mechanism of KM871 in mice. However their action was very weak compared with that in humans, and complement-mediated
cytotoxicity, which was strong in humans, was not observed in mice. Therefore, the antitumor activity of KM871 against human
melanomas evaluated by the nude mouse model might be underestimated. These results indicate that KM871 shows good antitumor
activity against GD3-positive human melanoma and the antitumor activity expected in humans might be superior to that of the
nude mouse model.
Received: 10 July 1999 / Accepted: 21 January 2000 相似文献
144.
Elongation factor 2 in the liver and skeletal muscle of mice is decreased by starvation 总被引:1,自引:0,他引:1
Yoshizawa F Miura Y Tsurumaru K Kimata Y Yagasaki K Funabiki R 《Bioscience, biotechnology, and biochemistry》2000,64(11):2482-2485
We examined whether starvation affected the amount of EF-2 protein as well as the level of its mRNA in the liver and skeletal muscle of mice, to understand the molecular mechanism for nutritional adaptation of protein-turnover. Although the amount of EF-2 was diminished by starvation in each of the tissues examined, the amount of EF-2 mRNA did not decrease in parallel with the protein. 相似文献
145.
To analyze genes involved in fruit body development of Pleurotus ostreatus, mRNAs from three different developmental stages: i.e., vegetative mycelium, primordium, and mature fruit body, were isolated and reverse-transcribed to cDNAs. One hundred and twenty random PCR amplifications were performed with the cDNAs, which generated 382, 394, 393 cDNA fragments from each developmental stage. From these fragments, four cDNA clones specifically expressed in primordium or mature fruit body were detected. Sequence analysis and database searches revealed significant similarity with triacylglycerol lipase, cytochrome P450 sterol 14 alpha-demethylase and developmentally regulated genes of other fungi. Northern blot analyses confirmed that all of the four cDNAs were unexpressed in mycelium, thus stage-specific genes for fruit body formation of P. ostreatus were successfully isolated. 相似文献
146.
Yamashita K Yamaguchi K Yamamoto T Shirabe S Hashiguchi N Kaji M Tochihara Y 《Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science》2005,24(6):611-615
The present study examined the effects of low humidity and hypobaric conditions on hematological change in venous blood of the lower leg during quiet prolonged sitting. Ten healthy male students participated as the subjects after singing a consent form to participate in this study. Their diet and water intake were controlled from 19:00 on the day before the experiments. The subjects sat for 130 min in a climatic chamber. Four experimental conditions in the chamber were designed from a combination of relative humidity (20% or 60%) and air pressure (sea level or equivalent to an altitude of 2,000 m). Ambient temperature was maintained at 24 degrees C in every condition. Venous blood was sampled from the lower leg before and after exposure to the experimental conditions, and was analyzed for blood viscosity and hematological indices. Also, body weight and leg circumference were measured as indices of total water loss and edema, respectively. Regarding the results of ANOVA, significant interactions between humidity and time were observed in blood viscosity, red blood cell count and hematocrit (each p<0.05). However, there were no significant differences in these indices among the conditions. Significant increases were observed in leg circumference (p<0.01), platelet count (p<0.05) and total protein (p<0.05) after the exposure compared with those before the exposure. There were no noticeable effects of hypobaric conditions in every measurement. In conclusion, prolonged sitting seems to be a more hazardous factor for thrombogenesis low humidity and hypobaric conditions during a long-distance flight. 相似文献
147.
148.
Yanagihara T Arai K Miyamae K Sato B Shudo T Yamada M Aoyama M 《Bioscience, biotechnology, and biochemistry》2005,69(10):1985-1987
A new type of electrolyzed hydrogen-saturated (EHS) water was produced using a water-electrolyzing device equipped with a special cation exchanger. Use of the EHS water for drinking in a feeding test with rats elicited an antioxidative effect. After intraperitoneal injection of 2,2-azobis-amidinopropane dihydrochloride, urinary secretion of 8-hydroxydeoxyguanosine and hepatic formation of peroxidized lipid were significantly lessened in rats which had received the EHS water for one week. These results suggest the possibility that this drinking water shows an effect in reduction of oxidative stress in the body. 相似文献
149.
In vivo kinetics of GITR and GITR ligand expression and their functional significance in regulating viral immunopathology 总被引:2,自引:0,他引:2
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This report evaluates the role of interaction between glucocorticoid-induced tumor necrosis factor receptor (GITR) and GITR ligand (GITR-L) in the immuno-inflammatory response to infection with herpes simplex virus (HSV). Both GITR and GITR-L were transiently upregulated after ocular HSV infection, on antigen-specific T cells and antigen-presenting cells, respectively, in the draining lymph node (DLN). In addition, virus-specific T-cell responses in the DLN and spleen were enhanced by anti-GITR antibody treatment, an outcome expected to result in more severe inflammatory lesions. Intriguingly, the treatment resulted in significantly diminished T-cell-mediated ocular lesions. The explanation for these findings was that anti-GITR antibody treatment caused a reduced production of ocular MMP-9, a molecule involved in ocular angiogenesis, an essential step in the pathogenesis of herpetic keratitis. Our results are the first observations to determine in vivo kinetics of GITR and GITR-L expression after virus infection, and they emphasize the role of GITR-GITR-L interaction to regulate virus-induced immuno-inflammatory lesions. 相似文献
150.
Upstream-migration of juvenileRhinogobius sp. OR was studied along the Ado River, a tributary of Lake Biwa. Juvenile gobies, mainly 18–21 mm in standard length, migrated
from the lake in a belt of about 3 m wide in lower reaches and about 10–20 cm wide in middler reaches. Their upstream-migration
was restricted to places shallower than 20 cm with bottom current velocities less than 20 cm/sec. Individual migration speed
varied between 4.2–8.9 m/min at places with bottom current velocity of 8.8–20.0 cm/sec, slowing down with increasing current
velocity. Most active migration occurred between 14:00 and 16:00, number of upstream-migrating juveniles decreasing with distance
from the river mouth. Riffles in the mid-and upper reaches, having few slow current areas, probably present barriers to upstream-migration
of the juvenile gobies, although both adults and subadults of the species are distributed in more upper reaches. 相似文献