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71.
Keiji Nagai Yukihiko Ueno Nobuo Takamiya Masao Kaneko 《Macromolecular chemistry and physics.》1995,196(4):1241-1250
The photoluminescent Ru(bpy) complex was dispersed in a polysiloxane film containing 2,2′-bipyridine (bpy) pendant groups. The unusually long photoluminescence lifetime of the Ru(bpy) (1,94 μs at 25°C) and the blue-shifted photoluminescent wavelength suggest a rigid polymer matrix. The fluorescence yield becomes lower with higher probe concentration, indicating concentration quenching. According to the analysis based on Stern-Volmer plots, the quenching obeys a mechanism composed of both static and dynamic processes. A statistical intermolecular distance distribution between the probes was used to interpret the results in terms of static and dynamic quenching. It is shown that in the present system the dispersed complexes diffuse slightly during the excited state. 相似文献
72.
Sumiya Ganzorig Yuzaburo Oku Munehiro Okamoto Ramiro Malgor Masao Kamiya 《Parasitology research》1999,85(7):597-600
This report describes a new species of aspidoderid nematode, Ansiruptodera scapteromi sp. nov., the second species to be reported in the genus Ansiruptodera Skrjabin and Shikhobalova, 1947. The A. scapteromi sp. nov. is the first species of the genus to be recorded from a rodent host. The new species is clearly different from the only other species, A. ansirupta (Proença, 1937) Skrjabin and Shikhobalova, 1947, in that it possesses short lateral alae that terminate before the midbody; a smaller cephalic extremity; a shorter esophagus, pharynx, tail, and tail appendage; a smaller sucker; and longer spicules. The two species also differ in the numbers and arrangements of caudal papillae. A. scapteromi appears to be a parasite of capture and the water rats seem to have been infected from Edentata in Uruguay. 相似文献
73.
Lack of association between DNA base excision repair gene XRCC1 Gln399Arg polymorphism and risk of malignant lymphoma in Japan 总被引:2,自引:0,他引:2
Matsuo K Hamajima N Suzuki R Andoh M Nakamura S Seto M Morishimae Y Tajima K 《Cancer Genetics and Cytogenetics》2004,149(1):77-80
Growing evidence suggests that the polymorphism of DNA base excision repair gene XRCC1 Arg399Gln is associated with altered DNA repair proficiency and subsequent cancer susceptibility; however, no evidence is available for malignant lymphoma. We therefore conducted a case-control study (372 cases, 500 controls) to evaluate links with malignant lymphoma risk in Japan. The risk was evaluated in terms of odds ratio (OR) and 95% confidence interval (CI) adjusted for age and sex in an unconditional logistic regression model. There was no statistical risk change with the Arg/Gln (adjusted OR 0.89; 0.65-1.23, P = 0.492) or the Gln/Gln (0.57; 0.27-1.17, P = 0.127) compared with the Arg/Arg of the XRCC1 Arg399Gln polymorphism. The results were unchanged in analyses according to histological subtype (diffuse large lymphoma, follicular lymphoma, low-grade lymphoma of mucosa-associated lymphoid tissue, and others). These data suggest that XRCC1 Gln399Arg polymorphism plays a limited role in lymphomagenesis. Further study on the interaction between the polymorphism and environmental exposure is required. 相似文献
74.
Kaoru Fujiyarna Masao Kishikawa Hideharu Fuji Tadayoshi Moriyarna Kengo Fuchigami Masachika Iseki Kiyoto Shinkai 《Pathology international》1990,40(5):376-382
We report a 6-year-old girl with anaplastic ependymoma probably originating in the region of the conus medullaris and probably spreading retrogradely to the region of the interventricular foramen (Monro) through the cere-brospinal fluid (CSF). Since ependymoma of the spinal cord rarely occurs in children, and retrograde spreading is extremely rare, the histological features and mechanism of metastasis of the tumor are discussed. 相似文献
75.
Fascin,an actin-bundling protein,modulates colonic epithelial cell invasiveness and differentiation in vitro 总被引:18,自引:0,他引:18 下载免费PDF全文
Jawhari AU Buda A Jenkins M Shehzad K Sarraf C Noda M Farthing MJ Pignatelli M Adams JC 《The American journal of pathology》2003,162(1):69-80
In epithelial tissue, cell-matrix and cell-cell adhesive interactions have important roles in the normal organization and stabilization of the cell layer. The malignant conversion of epithelial cells involves alterations in the expression and function of these adhesion systems that enable a switch to a migratory phenotype in tumor invasion and metastasis. Fascin is an actin-crosslinking protein that is found in the core actin bundles of cell-surface spikes and projections that are implicated in cell motility. We demonstrate that fascin is not detectable in normal colonic epithelium, but is dramatically up-regulated in colorectal adenocarcinoma. To test the hypothesis that fascin could participate in tumor invasive behavior, we developed a cell culture model to examine the effect of fascin expression on the adhesive interactions, invasiveness, and differentiation of colonic epithelial cells. We report marked effects on the organization of cell-surface protrusions, actin cytoskeleton, and focal adhesions in the absence of alterations in the protein levels of the major components of these structures. These effects correlate with alterations in cell movements on two-dimensional matrix, and increased invasiveness in three-dimensional matrix. The cells also show increased proliferation and decreased capacity for normal glandular differentiation in collagen gels. We propose that up-regulation of fascin, by promoting the formation of protrusive, actin-based, cell-motility structures, could be a significant component in the acquisition of invasive phenotype in colonic carcinoma. 相似文献
76.
Eishun Tsuchida Masao Kaneko Hiroyuki Nishide 《Macromolecular chemistry and physics.》1972,151(1):221-234
It was found that the oxidative polymerization of 2.6-xylenol with a copper-amine complex proceeds via a mechanism similar to that of a MICHAELIS-MENTEN-type reaction, the steady state being maintained during the polymerization; the kinetics were studied. The LINEWEAVER-BURK plots showed linear relationships, supporting this mechanism. From the comparison of the kinetic constants it was concluded that oxygen not only takes part in the recycling step of the catalyst, but also promotes the catalytic action of the cuprous complex by being coordinated to the intermediate complex. K1 values (the reciprocal of the MICHAELIS constant, Km) vary with the amine-ligand species, but the reaction-rate constants (k2) do not change, regardless of the ligands used. According to the kinetic formula, K1 is proportional to the product of the formation constant of the complex between the copper-amine catalyst and the monomer (K′1) by the rate constant of electron transfer (ke). It is because of the K′1 values that the apparent polymerization rate varies with the amine ligands in the region of relatively low monomer concentrations. It was found that, as the ligand ratio ([pyridine]/[Cu]) increases, i.e., as the selectivity for C? O coupling increases, the K1 values become larger. The mechanism for the coupling selectivity is discussed in relation to the K1 values. 相似文献
77.
Kuwahara S Mizukami T Omura M Hagihara M Iinuma Y Shimizu Y Tamada H Tsukamoto Y Nishida T Sasaki F 《The Anatomical record》2000,260(4):366-372
Seasonal changes in the hypothalamo-pituitary-testes axis of the Japanese wood mice (Apodemus speciosus) were studied. The testes, epididymis, pituitary and hypothalamus were compared between mice in the breeding season (July) and non-breeding season (October) using morphological techniques, and the plasma testosterone level was evaluated by enzyme immunoassay. Significant differences in these tissues were observed between the breeding season and the non-breeding season. Specifically, differences in the non-breeding season included 1) a decline in testicular and epididymal weights, arrest of spermatogenesis and decrease of serum testosterone concentration; 2) a decrease in the number of luteinizing hormone (LH)-, follicle stimulating hormone (FSH)-, prolactin (PRL)-, and growth hormone (GH)-immunoreactive cells, and decrease in the size of FSH, PRL, and GH-immunoreactive cells; and 3) an increase in the size of gonadotropin-releasing hormone (GnRH)-immunoreactive neurons. Our findings indicate that the male adult Japanese wood mouse exhibits unique seasonal changes in the hypothalamo-pituitary-testes axis which are not found in laboratory mice. 相似文献
78.
Shin Kobayashi Hiraku Uemura Takashi Kohda Toshiro Nagai Yasutsugu Chinen Kenji Naritomi Ei‐ichi Kinoshita Hirofumi Ohashi Kiyoshi Imaizumi Masato Tsukahara Yoshitsugu Sugio Hidefumi Tonoki Tatsuya Kishino Toshiaki Tanaka Masao Yamada Osamu Tsutsumi Norio Niikawa Tomoko Kaneko‐Ishino Fumitoshi Ishino 《American journal of medical genetics. Part A》2001,104(3):225-231
Silver‐Russell syndrome (SRS) is characterized by prenatal and postnatal growth retardation with morphologic anomalies. Maternal uniparental disomy 7 has been reported in some SRS patients. PEG1/MEST is an imprinted gene on chromosome 7q32 that is expressed only from the paternal allele and is a candidate gene for SRS. To clarify its biological function and role in SRS, we screened PEG1/MEST abnormalities in 15 SRS patients from various standpoints. In the lymphocytes of SRS patients, no aberrant expression patterns of two splice variants (α and β) of PEG1/MEST were detected when they were compared with normal samples. Direct sequence analysis failed to detect any mutations in the PEG1/MEST α coding region, and there were no significant mutations in the 5′‐flanking upstream region containing the predicted promoter and the highly conserved human/mouse genomic region. Differential methylation patterns of the CpG island for PEG1/MEST α were normally maintained and resulted in the same pattern as in the normal control, suggesting that there was no loss of imprinting. These findings suggest that PEG1/MEST can be excluded as a major determinant of SRS. © 2001 Wiley‐Liss, Inc. 相似文献
79.
Yukie Niwa Tsuyoshi Sakane Masao Shingu M. Mitsuo Yokoyama 《Journal of clinical immunology》1983,3(3):228-240
Neutrophils from the synovial fluid (SFN) of 10 patients with active rheumatoid arthritis (RA) were investigated to determine the generation of oxygen intermediates (OI) (O2-, H2O2, OH .), chemiluminescence, and lysosomal enzymes (lysozyme and beta-glucuronidase). Lymphocytes from healthy individuals were cocultured at 37 degrees C for 17 hr with SFN from the patients and the number of OKT4+, OKT8+, and OKT3+ cells and the response to mitogens were determined. A markedly increased OI and slightly elevated lysosomal enzyme levels were observed in SFN from patients. Coculture of lymphocytes with SFN resulted in a decreased number of OKT4+ and OKT8+ cells and a greatly reduced response to Con A and mildly diminished response to PHA, while OKT3+ cells were not affected. The simultaneous addition of superoxide dismutase and catalase restored the impairment of monoclonal antibody reaction and lymphocyte responsiveness almost to control levels. It is suggested that the disturbed immunoreactivity of synovial fluid lymphocytes from RA patients may be due to increased OI generated by stimulated neutrophils. 相似文献
80.
Photodegradation behavior for copolymers of styrene (St), α-methyl styrene (α-MSt) and methyl methacrylate (MMA) with methyl vinyl ketone (MVK) and phenyl vinyl ketone (PVK) in the presence of air was investigated in the solid state and in solution. Photolysis of St/MVK and St/PVK copolymers proceeded smoothly and an increase of the ketone in the copolymer resulted in an increase of the rate of degradation. Generally, the rate of degradation is faster in St/PVK copolymers than in St/MVK copolymers. It is likely that the degradation of the copolymers takes place mainly through NORRISH type II reaction. It was found that the photolysis of α-MSt/PVK copolymers was retarded considerably as compared with St/PVK copolymers. An unexpected behavior was observed in the case of MMA/MVK or MMA/PVK copolymers. These copolymers were expected to degrade with slow rates; they degraded, however, rapidly. Some experiments were done to explain this phenomenon. 相似文献