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排序方式: 共有626条查询结果,搜索用时 31 毫秒
121.
Young Kwan Kim Yoshitaka Kameo Sakae Tanaka Taiji Adachi 《Biomechanics and modeling in mechanobiology》2017,16(5):1697-1708
To understand Wolff’s law, bone adaptation by remodeling at the cellular and tissue levels has been discussed extensively through experimental and simulation studies. For the clinical application of a bone remodeling simulation, it is significant to establish a macroscopic model that incorporates clarified microscopic mechanisms. In this study, we proposed novel macroscopic models based on the microscopic mechanism of osteocytic mechanosensing, in which the flow of fluid in the lacuno-canalicular porosity generated by fluid pressure gradients plays an important role, and theoretically evaluated the proposed models, taking biological rationales of bone adaptation into account. The proposed models were categorized into two groups according to whether the remodeling equilibrium state was defined globally or locally, i.e., the global or local uniformity models. Each remodeling stimulus in the proposed models was quantitatively evaluated through image-based finite element analyses of a swine cancellous bone, according to two introduced criteria associated with the trabecular volume and orientation at remodeling equilibrium based on biological rationales. The evaluation suggested that nonuniformity of the mean stress gradient in the local uniformity model, one of the proposed stimuli, has high validity. Furthermore, the adaptive potential of each stimulus was discussed based on spatial distribution of a remodeling stimulus on the trabecular surface. The theoretical consideration of a remodeling stimulus based on biological rationales of bone adaptation would contribute to the establishment of a clinically applicable and reliable simulation model of bone remodeling. 相似文献
122.
Sonoike Kintake; Hatanaka Hideki; Katoh Sakae; Itoh Shigeru 《Plant & cell physiology》1990,31(6):865-870
Stabilities of iron-sulfur centers and reaction center chlorophyllP-700 in Photosystem I reaction center complex (CP1-a), isolatedby sodium dodecyl sulfate treatment from the thermophilic cyanobacteriumSynechococcus elongatus, were studied by EPR and optical spectroscopy.P-700 was destroyed by treatment at temperatures above 80?Cfor 5 minutes with a half inactivation temperature of 93?C.The three iron-sulfur centers FA, FB and FX showed similar thermalstabilities and were half inactivated at about 70?C. Thus, theisolated Photosystem I reaction center complexes of S. elongatusare still highly resistant to heat. (Received May 9, 1990; Accepted June 25, 1990) 相似文献
123.
Oxygen-evolving Photosystem II (PS II) particles were prepared from the thylakoid membranes of a chlorophyll b-less rice mutant, which totally lacks light-harvesting chlorophyll a/b proteins, after solubilization with β-octylglucoside. The preparation was essentially free of Photosystem I as judged from its low-temperature fluorescence spectrum and polypeptide composition. The PS II particles contained all the major subunit polypeptides of the PS II reaction center core complexes and the three extrinsic proteins related to oxygen evolution. The relative abundances of the 33, 21 and 15 kDa proteins were 100, 64 and 20%, respectively, of the corresponding proteins in the mutant thylakoids. The chlorophyll-to-QA ratio was 53 and there was only one bound Ca2+ per QA. Thus, one of the two bound Ca2+ present in the oxygen-evolving PS II membrane preparations from wild-type rice (Shen J.-R., Satoh, K. and Katoh, S. (1988) Biochim. Biophys. Acta 933, 358–364) is missing. The mutant PS II particles were highly active in oxygen evolution in the absence of exogenously added Ca2+, although addition of 5 mM Ca2+ enhanced the activity by 30%. When the 21 and 15 kDa proteins were supplemented to the particles, the Ca2+-effect disappeared and the rate of oxygen evolution increased to a level exceeding 1000 μmol O2 per mg chlorophyll per h. The results indicate that the number of Ca2+ needed to promote a high rate of oxygen evolution is one per PS II in higher plants. 相似文献
124.
Natsumi Saito Tomohiko Ishihara Kensaku Kasuga Mana Nishida Takanobu Ishiguro Hiroaki Nozaki 《朊病毒》2018,12(2):147-149
We report a Japanese patient with spinocerebellar ataxia type 31 (SCA31) and sporadic Creutzfeldt-Jakob disease (sCJD). A 52-year-old man developed progressive cognitive impairment after the appearance of cerebellar symptoms. Brain MR diffusion-weighted imaging (DWI) demonstrated a slowly expanding hyperintense lesion in the cerebral cortex. The patient was finally diagnosed as having both SCA31 and sCJD by identification of genetic mutations and by real-time quaking-induced conversion (RT-QUIC) analysis of the cerebrospinal fluid (CSF), respectively. Here, we report the clinical details of this rare combined case, with particular reference to the association between prion protein and the early onset of SCA31. 相似文献
125.
Gakuro Harada Shiori Onoue Chisato Inoue Sakae Hanada Yoshinori Katakura 《Cytotechnology》2018,70(6):1707-1712
Delphinidin is an anthocyanidin commonly found in various fruits and vegetables. Delphinidin has been known to possess many functions, such as an antioxidant, and anti-inflammatory, anti-cancer and anti-muscular atrophy agent. In this study, we attempted to evaluate the effects of delphinidin on lipid accumulation in hepatocytes. The results showed that palmitic acid (PA)-induced cellular senescence in HepG2 cells and reduced the expression of SMARCD1, which is known to regulate senescence-associated lipid accumulation in hepatocytes. However, delphinidin-3-glucoside (D3 g) suppressed PA-induced senescence and reversed the expression of SMARCD1 to the level of untreated HepG2 cells. Consequently, D3 g inhibited PA-induced lipid accumulation through the restoration of the expression of SMARCD1 and fatty acid oxidation genes. Taken together, our results suggest that D3 g suppresses the lipid accumulation induced by hepatocyte senescence. 相似文献
126.
Yamasaki Takenobu; Kudoh Toshiyuki; Kamimura Yasumaro; Katoh Sakae 《Plant & cell physiology》1996,37(1):43-48
The abundances of chloroplasts in leaves on the main stems ofChenopodium album at different height levels were investigatedin relation to the photosynthetic capacity and light environmentof the leaves. (1) The number of chloroplasts per mesophyllcell decreased with descending position of leaves, except foryoung developing leaves at the top of plants that had smallerchloroplast numbers per cell than matured leaves beneath them.Contents of chlorophyll and ribulose-1,5-bisphosphate carboxylase/oxygenaseper leaf area that were highest in the topmost young leavesand decreased with decreasing height level indicate that thereis a vertical gradient of chloroplast abundance per leaf areadecreasing from the top of the leaf canopy with depth. (2) Light-saturatingrate of photosynthetic oxygen evolution per leaf area of maturedleaves decreased more steeply with decreasing leaf positionthan the chloroplast number per cell. Gradients of chlorophylland the enzyme protein contents were also steeper than thatof the chloroplast number. Loss of photosynthesis in lower leavesis, therefore, ascribed partly to loss of whole chloroplastsand partly to reduced photosynthetic capacities of the remainingchloroplasts. (3) The chloroplast number per cell in newly expandedsecond leaves was comparable to those in leaves that have developedat later stages of the plant growth but decreased graduallyduring leaf senescence both in the dark and light. The formationof the vertical gradient of chloroplast abundance is, therefore,ascribed to loss of whole chloroplasts during senescence ofleaves. (4) Irradiance a leaf receives decreased sharply fromthe top of the canopy with depth. The physiological or ecophysiologicalsignificance of the vertical distribution of chloroplasts amongleaves was discussed taking light environments of leaves intoconsideration. (Received July 31, 1995; Accepted October 20, 1995) 相似文献
127.
128.
Augusto Takaschima Patricia Marchioro Thiago M. Sakae André L. Porporatti Luis André Mezzomo Graziela De Luca Canto 《PloS one》2016,11(1)
Background
Patients undergoing ophthalmic surgery are usually elderly and, due to systemic disease, may be on long-term therapy, such as antithrombotic agents. Rates of hemorrhagic complications associated with invasive procedures may be increased by the use of anticoagulants and antiplatelet agents.Objective
To compare the incidence of hemorrhagic complications in patients undergoing needle-based ophthalmic regional anesthesia between patients on antithrombotic therapy and those not on such therapy.Methods
A systematic review was conducted by two independent reviewers based on searches of Cochrane, LILACS, PubMed, Scopus, Web of Science, and the “gray” literature (Google Scholar). The end search date was May 8, 2015, across all databases.Results
Five studies met the eligibility criteria. In three studies, individual risk of bias was low, and in two of them, moderate. In all studies, no differences regarding mild to moderate incidence of hemorrhagic complications were found between patients using antithrombotics (aspirin, clopidogrel, and warfarin) and those not using them. Rates of severe hemorrhagic complication were very low (0.04%) in both groups, supporting the safety of needle blocks, even in patients using antithrombotics. High heterogeneity across studies prevented meta-analysis. Limitations to these results include low statistical power in three experimental studies and a large 95% confidence interval in the two retrospective cohorts.Conclusion
In this review, none of the selected studies showed significant bleeding related to needle-based ophthalmic regional anesthesia in association with the use of aspirin, clopidogrel, or vitamin K inhibitors. Since the available data is not powerful enough to provide a reliable evaluation of the true effect of antithrombotics in this setting, new studies to address these limitations are necessary. 相似文献129.
Preparation and Characterization of P700-Enriched Photosystem-I Complexes from the Thermophilic Cyanobacterium, Synechococcus sp. 总被引:1,自引:0,他引:1
P700 was enriched relative to antenna pigments by treating thethylakoid membranes from thermophilic cyanobacterium (Synechococcussp.) with diethylether. The total Chi a/P700 ratio of the membraneswas 147 but decreased to 13 after the treatment with ether whichhad been 70% saturated with water. Vitamin K1 and carotenoidswere completely removed by this treatment. The low chlorophylla to P700 ratio was retained in photosystem I reaction-centercomplexes purified from the ether-extracted membranes with TritonX-100. The midpoint potential of P700 was considerably loweredby the ether treatment of the thylakoid membranes but was partiallyreversed by the further treatment of the extracted membraneswith Triton X-100. Photo-oxidation of P700 in the purified complexeswas extremely slow under continuous illumination, indicatingthat there is no significant leakage of electrons from the primaryelectron acceptor to other bound acceptors or O2. The photooxidationof P700 was appreciably accerelated on addition of vitamin K3(or K1). (Received June 23, 1988; Accepted November 25, 1988) 相似文献
130.
Sakae Arimoto Yoshiko Ohara Takako Namba Tomoe Negishi Hikoya Hayatsu 《Biochemical and biophysical research communications》1980,92(2):662-668
Inhibition of the mutagenic activities of the amino acid pyrolysis products by hemin and other biological pyrrole pigments was investigated using the Ames' /microsome system. Hemin, biliverdin and chlorophyllin showed inhibition to all the six mutagens tested, and protoporphyrin to three of them. Hemin was the most effective among these pigments; e.g., the mutageniciti of 1.8 nmole Trp-P-1 (3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole) was suppressed to 50 % by 1–3 nmole of hemin. Hemin appears to interact with the metabolically activated form of Trp-P-1 and as a result to inhibit the mutagenicity. 相似文献