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Articles by K Sato
Total Records ( 8 ) for K Sato
  N Okishiro , M Miyashita , S Tsuneto , K Sato and Y. Shima
 

There has been a debate in appropriateness of legalization of death with dignity and euthanasia in Japan. To clarify views about these issues, we conducted a large nationwide study of the bereaved whose family member died at palliative care units. The percentages of 429 bereaved family members (response rate 65%) who affirmed legal authorization were 52 for death with dignity and 45 for euthanasia and who affirmed assignment at the discretion of the physician involved were 37 for death with dignity and 38 for euthanasia. In conclusion, views about legalization of death with dignity and euthanasia among the bereaved are inconsistent. No consensus is reached as to legislation of these issues.

  M Hamada , K Sato , H Kiryu , T Mituyama and K. Asai
 

Motivation: Secondary structure prediction of RNA sequences is an important problem. There have been progresses in this area, but the accuracy of prediction from an RNA sequence is still limited. In many cases, however, homologous RNA sequences are available with the target RNA sequence whose secondary structure is to be predicted.

Results: In this article, we propose a new method for secondary structure predictions of individual RNA sequences by taking the information of their homologous sequences into account without assuming the common secondary structure of the entire sequences. The proposed method is based on posterior decoding techniques, which consider all the suboptimal secondary structures of the target and homologous sequences and all the suboptimal alignments between the target sequence and each of the homologous sequences. In our computational experiments, the proposed method provides better predictions than those performed only on the basis of the formation of individual RNA sequences and those performed by using methods for predicting the common secondary structure of the homologous sequences. Remarkably, we found that the common secondary predictions sometimes give worse predictions for the secondary structure of a target sequence than the predictions from the individual target sequence, while the proposed method always gives good predictions for the secondary structure of target sequences in all tested cases.

Availability: Supporting information and software are available online at: http://www.ncrna.org/software/centroidfold/ismb2009/.

Contact: hamada-michiaki@aist.go.jp

Supplementary information:Supplementary data are available at Bioinformatics online.

  S Hirano , H Shinotoh , H Shimada , A Aotsuka , N Tanaka , T Ota , K Sato , H Ito , S Kuwabara , K Fukushi , T Irie and T. Suhara
 

Corticobasal syndrome, progressive supranuclear palsy and frontotemporal dementia are all part of a disease spectrum that includes common cognitive impairment and movement disorders. The aim of this study was to characterize brain cholinergic deficits in these disorders. We measured brain acetylcholinesterase activity by [11C] N-methylpiperidin-4-yl acetate and positron emission tomography in seven patients with corticobasal syndrome (67.6 ± 5.9 years), 12 with progressive supranuclear palsy (68.5 ± 4.1 years), eight with frontotemporal dementia (59.8 ± 6.9 years) and 16 healthy controls (61.2 ± 8.5 years). Two-tissue compartment three-parameter model and non-linear least squares analysis with arterial input function were performed. k3 value, an index of acetylcholinesterase activity, was calculated voxel-by-voxel in the brain of each subject. The k3 images in each disease group were compared with the control group by using Statistical Parametric Mapping 2. Volume of interest analysis was performed on spatially normalized k3 images. The corticobasal syndrome group showed decreased acetylcholinesterase activity (k3 values) in the paracentral region, frontal, parietal and occipital cortices (P < 0.05, cluster corrected). The group with progressive supranuclear palsy had reduced acetylcholinesterase activity in the paracentral region and thalamus (P < 0.05, cluster corrected). The frontotemporal dementia group showed no significant differences in acetylcholinesterase activity. Volume of interest analysis showed mean cortical acetylcholinesterase activity to be reduced by 17.5% in corticobasal syndrome (P < 0.001), 9.4% in progressive supranuclear palsy (P < 0.05) and 4.4% in frontotemporal dementia (non-significant), when compared with the control group. Thalamic acetylcholinesterase activity was reduced by 6.4% in corticobasal syndrome (non-significant), 24.0% in progressive supranuclear palsy (P < 0.03) and increased by 3.3% in frontotemporal dementia (non-significant). Both corticobasal syndrome and progressive supranuclear palsy showed brain cholinergic deficits, but their distribution differed somewhat. Significant brain cholinergic deficits were not seen in frontotemporal dementia, which may explain the unresponsiveness of this condition to cholinergic modulation therapy.

  S. A McCalmon , D. M Desjardins , S Ahmad , K. S Davidoff , C. M Snyder , K Sato , K Ohashi , O. M Kielbasa , M Mathew , E. P Ewen , K Walsh , H Gavras and F. J. Naya
 

Rationale: The vasoactive peptide angiotensin II (Ang II) is a potent cardiotoxic hormone whose actions have been well studied, yet questions remain pertaining to the downstream factors that mediate its effects in cardiomyocytes.

Objective: The in vivo role of the myocyte enhancer factor (MEF)2A target gene Xirp2 in Ang II–mediated cardiac remodeling was investigated.

Methods and Results: Here we demonstrate that the MEF2A target gene Xirp2 (also known as cardiomyopathy associated gene 3 [CMYA3]) is an important effector of the Ang II signaling pathway in the heart. Xirp2 belongs to the evolutionarily conserved, muscle-specific, actin-binding Xin gene family and is significantly induced in the heart in response to systemic administration of Ang II. Initially, we characterized the Xirp2 promoter and demonstrate that Ang II activates Xirp2 expression by stimulating MEF2A transcriptional activity. To further characterize the role of Xirp2 downstream of Ang II signaling we generated mice harboring a hypomorphic allele of the Xirp2 gene that resulted in a marked reduction in its expression in the heart. In the absence of Ang II, adult Xirp2 hypomorphic mice displayed cardiac hypertrophy and increased β myosin heavy chain expression. Strikingly, Xirp2 hypomorphic mice chronically infused with Ang II exhibited altered pathological cardiac remodeling including an attenuated hypertrophic response, as well as diminished fibrosis and apoptosis.

Conclusions: These findings reveal a novel MEF2A-Xirp2 pathway that functions downstream of Ang II signaling to modulate its pathological effects in the heart.

  K Sato , T Sato , J Furuse , H Kasugai , M Konishi , T Kosuge , A Saito , Y Sasaki , K Takasaki and T. Okusaka
  Objective

The aim of this study was to explore why patients accepted or declined to participate in a randomized clinical trial, which was subsequently discontinued because of a low recruitment rate.

Methods

Forty-one patients were invited to participate in a randomized clinical trial that aimed to compare local ablation therapies and surgery to treat small asymptomatic hepatocellular carcinomas. These patients were then asked to answer a questionnaire that assessed patient perception and reasons for accepting or declining to enroll in the randomized clinical trial. When patients had a strong preference for a specific treatment, the questionnaire assessed why, how and when they had chosen it.

Results

The response rate was 6/6 (100%) and 30/35 (86%) for the participant and non-participant groups, respectively. Among the 30 non-participants, 23 had a strong preference for local ablation therapies, which was less invasive and offered shorter hospitalization. Patient preference for a specific treatment often stemmed from their consultations with a clinician who referred them to a specialist hospital. Patients without strong preference for a specific treatment participated in the randomized clinical trial because of altruistic motivations.

Conclusion

When new treatments that are innovative and less burdensome become widespread, they are difficult to compare with standard therapy utilizing a well-designed randomized clinical trial. Consequently, when an innovative treatment is developed, investigators should consider designing a randomized clinical trial as early as possible.

  Y Nishina , K Sato , H Tamaoki , C Setoyama , R Miura and K. Shiga
 

The interactions of acyl-CoA with medium-chain acyl-CoA dehydrogenases (MCADs) reconstituted with artificial FADs—i.e. 8-CN-, 7,8-Cl2-, 8-Cl-, 8-OCH3- and 8-NH2-FAD—were investigated by UV-visible absorption and FT-IR measurements. Although 8-NH2-FAD-MCAD did not oxidize acyl-CoA the wavelength of the absorption maximum of the flavin was altered by acyl-CoAs binding. Thus, 8-NH2-FAD-MCAD is one of the attractive materials for investigation of enzyme–substrate (ES) interaction in ES complex (the complex of oxidized MCAD with acyl-CoA). FT-IR difference spectra between non-labelled and [1-13C]-labelled acyl-CoA free in solution and bound to oxidized 8-NH2-FAD-MCAD were obtained. The broad 1668-cm–1 band of free octanoyl-CoA assigned to the C(1) = O stretching vibration appeared as a sharp signal at 1626 cm–1 in the case of the complex. The downward shift indicates a large polarization of C(1) = O, and the sharpness suggests that the orientation of the C(1) = O in the active-site cavity is fairly limited. The hydrogen-bond enthalpy change responsible for the polarization on the transfer of the substrate from aqueous solution to the active site of MCAD was estimated to be ~15 kcal/mol. The 1626-cm–1 band is noticeably weakened in the case of acyl-CoA with acyl chains longer than C12 which are poor substrates for MCAD, suggesting that C(1) = O is likely to exist in multiple orientations in the active-site cavity, whence the band becomes obscured. A band identical to that of bound C8-CoA was observed in the case of C4-CoA which is a poor substrate, indicating the strong hydrogen bond at C(1) = O.

  W. J McKinstry , G Polekhina , H Diefenbach Jagger , P. W. M Ho , K Sato , E Onuma , M. T Gillespie , T. J Martin and M. W. Parker
 

Parathyroid hormone-related protein (PTHrP) plays a vital role in the embryonic development of the skeleton and other tissues. When it is produced in excess by cancers it can cause hypercalcemia, and its local production by breast cancer cells has been implicated in the pathogenesis of bone metastasis formation in that disease. Antibodies have been developed that neutralize the action of PTHrP through its receptor, parathyroid hormone receptor 1, without influencing parathyroid hormone action through the same receptor. Such neutralizing antibodies against PTHrP are therapeutically effective in animal models of the humoral hypercalcemia of malignancy and of bone metastasis formation. We have determined the crystal structure of the complex between PTHrP (residues 1–108) and a neutralizing monoclonal anti-PTHrP antibody that reveals the only point of contact is an -helical structure extending from residues 14–29. Another striking feature is that the same residues that interact with the antibody also interact with parathyroid hormone receptor 1, showing that the antibody and the receptor binding site on the hormone closely overlap. The structure explains how the antibody discriminates between the two hormones and provides information that could be used in the development of novel agonists and antagonists of their common receptor.

 
 
 
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