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排序方式: 共有574条查询结果,搜索用时 15 毫秒
1.
T Oyama T Osaki T Mitsudomi R Ogawa R Nakanishi K Sugio K Yasumoto 《Canadian Metallurgical Quarterly》1998,1(5):823-826
We examined p53 protein expression, p53 gene mutation, proliferating cell nuclear antigen (PCNA), and argyrophilic nuclear organizer regions (AgNOR), in 30 patients with surgically-treated thymic tumors (26 thymoma and 4 thymic carcinoma cases). p53 expression ratio with DO-1 was divided as p53 negative (0% positivity), low expressor (<10% positivity), high expressor (>10% positivity). The incidence of p53 low and high expressor in thymoma were 19% (5/26) and 8% (2/26), respectively. p53 immunopositivity in thymoma was significantly correlated with PCNA labeling index (LI). p53 expression ratio in invasive thymoma (33%) tended to be higher than that in non-invasive thymoma (18%). p53 expression was detected in one of the thymic carcinoma. There were no p53 gene mutations in 15 invasive thymoma, although one of four (25%) thymic carcinomas showed two point mutations. p53 gene alterations seem to be associated with malignant activity of tumor cells, and therefore detection of p53 gene mutations is useful as a diagnostic factor. 相似文献
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T Shirasaka K Nakano T Takechi H Satake J Uchida A Fujioka H Saito H Okabe K Oyama S Takeda N Unemi M Fukushima 《Canadian Metallurgical Quarterly》1996,56(11):2602-2606
The purpose of this study was to establish a nude rat orthotopic (organ-specific) human colorectal cancer model as an in vivo secondary screen for general evaluation of new anticancer agents against colorectal cancer and to evaluate practically the antitumor activity of 1 M tegafur-0.4 M 5-chloro-2,4-dihydroxypyridine-1 M potassium oxonate (S-1), a new p.o. fluoropyrimidine, in comparison to 1 M tegafur-4 M uracil [(UFT) effective on colorectal tumor in clinical]. After implantation of KM12C, a human colorectal cancer cell line, into the subserosal layer of the colon as a single-cell suspension, extensive local tumor growth and invasion to both the mucosal and the serosal sides were observed in all rats. Metastatic foci were also formed in both lymph nodes and lungs following local tumor growth in all of them. Using this method, an equitoxic dose of S-1 (15 mg/kg/day) and UFT (30 mg/kg/day) was administered p.o. for 14 consecutive days from 7 days after tumor cell implantation. S-1 showed a higher tumor growth inhibition than UFT did [S-1, 57% (significantly different from the tumor weight of the untreated group at P < 0.05) and UFT, 18% (P > 0.05)]. When both drugs were administered to nude rats bearing KM12C injected into the cecal wall for 28 consecutive days at equitoxic doses, the mean survival in the S-1 group was 16 days longer than that in the untreated group (P < 0.01) but that in the UFT group was only 8 days longer (P > 0.05). After the administration of an equitoxic dose of both drugs, S-1 gave the higher levels than UFT in various pharmacokinetic parameters as follows: area under the curve 0-24 h of 5-fluorouracil in plasma (3.5-fold), area under the curve 0-24 h of 5-fluorouracil incorporated into RNA in the tumor (1.3-fold), and thymidylate synthase inhibition rate (percentage) in the tumor (about 20%). Collectively, these findings suggested that this orthotopic human colorectal tumor model in nude rats is useful to evaluate the clinical therapeutic efficacy of drugs or therapies for colorectal cancer, and that S-1 had a higher therapeutic effect on human colorectal tumor than UFT did. 相似文献
4.
A screening test was undertaken to isolate a microorganism that produced 5-oxoprolinase (without ATP-hydrolyzing). The 5-oxoprolinase (without ATP-hydrolyzing) activity (decyclization activity toward L-pyroglutamate) was found in a cell-free extract of Alcaligenes faecalis N-38A, newly isolated from a soil sample. The enzyme was purified as a homogeneous preparation. The molecular weight of the enzyme was estimated to be 47,000. The decyclization activity was specific for L-pyroglutamate, and independent of ATP and metal ions. The reaction was a reversible one, i.e., cyclization reaction of L-glutamate to yield pyroglutamate was identified. 相似文献
5.
A new class of materials, MI-MII-O-N (where MI, MII = V, Mo, W, and Nb), has been synthesized by nitriding bimetallic oxide precursors with ammonia gas via a temperature programmed reaction. The oxide precursors are prepared by conventional solid state reaction between two appropriate monometallic oxides. The synthesis of the oxynitrides involves passing NH3 gas over the oxide precursors at a flow rate of 6.80×102 mols–1 (1000 cm3 min–1), and raising the temperature at a rate of 8.3×10–2 Ks–1 (5K min–1) to a final temperature which is held constant for a short period of time. The oxynitrides thus obtained are pyrophoric and need to be passivated before exposing them to air. All these new bimetallic oxynitrides have a face centered cubic (f.c.c.) metal arrangement and high values of surface area. Their surface activity is assessed from their ability to chemisorb CO. 相似文献
6.
Ono Yuya Kurashige Kentarou Hakim Afiqe Anuar Bin Muhammad Nor Sakamoto Yuma 《Artificial Life and Robotics》2023,28(2):287-294
Artificial Life and Robotics - Although the design of the reward function in reinforcement learning is important, it is difficult to design a system that can adapt to a variety of environments and... 相似文献
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8.
Daichi Amagata Yuya Sasaki Takahiro Hara Shojiro Nishio 《Distributed and Parallel Databases》2016,34(2):259-287
A nearest neighbor (NN) query, which returns the most similar object to a user-specified query object, plays an important role in a wide range of applications and hence has received considerable attention. In many such applications, e.g., sensor data collection and location-based services, objects are inherently uncertain. Furthermore, due to the ever increasing generation of massive datasets, the importance of distributed databases, which deal with such data objects, has been growing. One emerging challenge is to efficiently process probabilistic NN queries over distributed uncertain databases. The straightforward approach, that each local site forwards its own database to the central server, is communication-expensive, so we have to minimize communication cost for the NN object retrieval. In this paper, we focus on two important queries, namely top-k probable NN queries and probabilistic star queries, and propose efficient algorithms to process them over distributed uncertain databases. Extensive experiments on both real and synthetic data have demonstrated that our algorithms significantly reduce communication cost. 相似文献
9.
A neural oscillator with a double-chain structure is one of the central pattern generator models used to simulate and understand rhythmic movements in living organisms. However, it is difficult to reproduce desired rhythmic signals by tuning an enormous number of parameters of neural oscillators. In this study, we propose an automatic tuning method consisting of two parts. The first involves tuning rules for both the time constants and the amplitude of the oscillatory outputs based on theoretical analyses of the relationship between parameters and outputs of the neural oscillators. The second involves an evolutionary tuning method with a two-step genetic algorithm (GA), consisting of a global GA and a local GA, for tuning parameters such as neural connection weights that have no exact tuning rule. Using numerical experiments, we confirmed that the proposed tuning method could successfully tune all parameters and generate sinusoidal waves. The tuning performance of the proposed method was less affected by factors such as the number of excitatory oscillators or the desired outputs. Furthermore, the proposed method was applied to the parameter-tuning problem of some types of artificial and biological wave reproduction and yielded optimal parameter values that generated complex rhythmic signals in Caenorhabditis elegans without trial and error. 相似文献
10.
Akihiro Honda Shotaro Kamata Makoto Akahane Yui Machida Kie Uchii Yui Shiiyama Yuki Habu Saeka Miyawaki Chihiro Kaneko Takuji Oyama Isao Ishii 《International journal of molecular sciences》2022,23(9)
Among the agonists against three peroxisome proliferator-activated receptor (PPAR) subtypes, those against PPARα (fibrates) and PPARγ (glitazones) are currently used to treat dyslipidemia and type 2 diabetes, respectively, whereas PPARδ agonists are expected to be the next-generation metabolic disease drug. In addition, some dual/pan PPAR agonists are currently being investigated via clinical trials as one of the first curative drugs against nonalcoholic fatty liver disease (NAFLD). Because PPARα/δ/γ share considerable amino acid identity and three-dimensional structures, especially in ligand-binding domains (LBDs), clinically approved fibrates, such as bezafibrate, fenofibric acid, and pemafibrate, could also act on PPARδ/γ when used as anti-NAFLD drugs. Therefore, this study examined their PPARα/δ/γ selectivity using three independent assays—a dual luciferase-based GAL4 transactivation assay for COS-7 cells, time-resolved fluorescence resonance energy transfer-based coactivator recruitment assay, and circular dichroism spectroscopy-based thermostability assay. Although the efficacy and efficiency highly varied between agonists, assay types, and PPAR subtypes, the three fibrates, except fenofibric acid that did not affect PPARδ-mediated transactivation and coactivator recruitment, activated all PPAR subtypes in those assays. Furthermore, we aimed to obtain cocrystal structures of PPARδ/γ-LBD and the three fibrates via X-ray diffraction and versatile crystallization methods, which we recently used to obtain 34 structures of PPARα-LBD cocrystallized with 17 ligands, including the fibrates. We herein reveal five novel high-resolution structures of PPARδ/γ–bezafibrate, PPARγ–fenofibric acid, and PPARδ/γ–pemafibrate, thereby providing the molecular basis for their application beyond dyslipidemia treatment. 相似文献