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Hokkaido University Collection of Scholarly and Academic Papers (130.615 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

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Mostrando recursos 1 - 10 de 10

  1. Dynamic PET evaluation of elevated FLT level after sorafenib treatment in mice bearing human renal cell carcinoma xenograft

    Ukon, Naoyuki; Zhao, Songji; Yu, Wenwen; Shimizu, Yoichi; Nishijima, Ken-ichi; Kubo, Naoki; Kitagawa, Yoshimasa; Tamaki, Nagara; Higashikawa, Kei; Yasui, Hironobu; Kuge, Yuji
    Background: Sorafenib, an oral multikinase inhibitor, has anti-proliferative and anti-angiogenic activities and is therapeutically effective against renal cell carcinoma (RCC). Recently, we have evaluated the tumor responses to sorafenib treatment in a RCC xenograft using [Methyl-3H(N)]-3'-fluoro-3'-deoxythythymidine ([3H]FLT). Contrary to our expectation, the FLT level in the tumor significantly increased after the treatment. In this study, to clarify the reason for the elevated FLT level, dynamic 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT) positron emission tomography (PET) and kinetic studies were performed in mice bearing a RCC xenograft (A498). The A498 xenograft was established in nude mice, and the mice were assigned to the control (n...

  2. Imaging Mass Spectrometry Reveals Acyl-Chain- and Region-Specific Sphingolipid Metabolism in the Kidneys of Sphingomyelin Synthase 2-Deficient Mice

    Sugimoto, Masayuki; Wakabayashi, Masato; Shimizu, Yoichi; Yoshioka, Takeshi; Higashino, Kenichi; Numata, Yoshito; Okuda, Tomohiko; Zhao, Songji; Sakai, Shota; Igarashi, Yasuyuki; Kuge, Yuji
    Obesity was reported to cause kidney injury by excessive accumulation of sphingolipids such as sphingomyelin and ceramide. Sphingomyelin synthase 2 (SMS2) is an important enzyme for hepatic sphingolipid homeostasis and its dysfunction is considered to result in fatty liver disease. The expression of SMS2 is also high in the kidneys. However, the contribution of SMS2 on renal sphingolipid metabolism remains unclear. Imaging mass spectrometry is a powerful tool to visualize the distribution and provide quantitative data on lipids in tissue sections. Thus, in this study, we analyzed the effects of SMS2 deficiency on the distribution and concentration of sphingomyelins in...

  3. In vivo imaging of membrane type-1 matrix metalloproteinase with a novel activatable near-infrared fluorescence probe

    Shimizu, Yoichi; Temma, Takashi; Hara, Isao; Makino, Akira; Kondo, Naoya; Ozeki, Ei-ichi; Ono, Masahiro; Saji, Hideo
    Membrane type-1 matrix metalloproteinase (MT1-MMP) is a protease activating MMP-2 that mediates cleavage of extracellular matrix components and plays pivotal roles in tumor migration, invasion and metastasis. Because in vivo noninvasive imaging of MT1-MMP would be useful for tumor diagnosis, we developed a novel near-infrared (NIR) fluorescence probe that can be activated following interaction with MT1-MMP in vivo. MT1-hIC7L is an activatable fluorescence probe comprised of anti-MT1-MMP monoclonal antibodies conjugated to self-assembling polymer micelles that encapsulate NIR dyes (IC7-1, em: 858nm) at concentrations sufficient to cause fluorescence self-quenching. In aqueous buffer, MT1-hIC7L fluorescence was suppressed to background levels and increased...

  4. Evaluation of delineation of image details in semiconductor PET utilizing the normalized mutual information technique

    Kubo, Naoki; Hirata, Kenji; Matsuzaki, Kazuki; Morimoto, Yuichi; Takeuchi, Wataru; Hattori, Naoya; Shiga, Tohru; Kuge, Yuji; Tamaki, Nagara
    PET using semiconductor detectors provides high-quality images of the human brain because of its high spatial resolution. To quantitatively evaluate the delineation of image details in clinical PET images, we used normalized mutual information (NMI) to quantify the similarity with images obtained through MRI. NMI is used to evaluate image quality by determining similarity with a reference image. The aim of this study was to evaluate quantitatively the delineation of image details provided by semiconductor PET.

  5. Suppressive Effects of Irbesartan on Inflammation and Apoptosis in Atherosclerotic Plaques of apoE(-/-) Mice: Molecular Imaging with C-14-FDG and Tc-99m-Annexin A5

    Zhao, Yan; Watanabe, Ayahisa; Zhao, Songji; Kobayashi, Tatsuo; Fukao, Keita; Tanaka, Yoshikazu; Nakano, Toru; Yoshida, Tetsuya; Takemoto, Hiroshi; Tamaki, Nagara; Kuge, Yuji
    Objectives: To investigate the effects of irbesartan on inflammation and apoptosis in atherosclerotic plaques by histochemical examination and molecular imaging using C-14-FDG and Tc-99m-annexin A5. Background: Irbesartan has a peroxisome proliferator-activated receptor gamma (PPAR gamma) activation property in addition to its ability to block the AT1 receptor. Accordingly, irbesartan may exert further anti-inflammatory and anti-apoptotic effects in atherosclerotic plaques. However, such effects of irbesartan have not been fully investigated. Molecular imaging using F-18-FDG and Tc-99m-annexin A5 is useful for evaluating inflammation and apoptosis in atherosclerotic plaques. Methods: Female apoE(-/-) mice were treated with irbesartan-mixed (50 mg/kg/day) or irbesartan-free (control) diet...

  6. Some Considerations on Image Reconstruction : A description of filtered back projection and iterative reconstruction

    Kubo, Naoki
    The following two duties are expected of us: (1) to assist in interpretation of diagnostic images, and (2) to provide detailed explanations of radiological examinations. As professionals, we owe it to our clients to maintain our competence in perceiving the reality of each person’s condition during radiological examinations; we must neither nderestimate their radiation exposure risks nor overestimate the benefits they may receive from the examination. When assisting in interpretation of diagnostic images, we must understand the characteristics of images that can affect our assessment. Moreover, turning to the topic of reconstructed images, much information can be gathered from images...

  7. Uncollimated scintigram image restoration

    Kubo, Naoki; Hanada, Hiroyuki
    We have conducted an experiment on restoring scintigram images obtained without the use of collimators. Uncollimated images of liver slice phantoms filled with 99mTc were taken at a phantom-camera distance of 0 cm. The sensitivity under these conditions was about one thousand times higher than that using a low-energy high-resolution collimator. Uncollimated images were restored using unsharp masking in combination with spatial filtering. The unsharp masking process involved subtracting two images taken at phantom-camera distances of 0 and 2.3 cm to produce a difference image. The mean squared errors found were 0.56 for the uncollimated images, 0.54 for the images...

  8. フィルタ補正逆投影法・逐次近似法について

    久保, 直樹

  9. Versatile Photorearrangement of Photocycloadducts from 5-Fluoro-1,3-dimethyluracil and Naphthalene

    Ohkura, Kazue; Akizawa, Hiromichi; Kudo, Mikiko; Ishihara, Tetsuya; Oshima, Nobuhiro; Seki, Koh-ichi
    Direct UV-irradiation of 5-fluoro-1,3-dimethyluracil (5-FDMU) and naphthalene (1) with a 500 W high-pressure mercury lamp in a degassed Pyrex tube (λ > 300 nm) predominantly afforded benzopyrimidobarrelene derivative (2) through 1,4-addition, while irradiation in the presence of piperylene in singlet excited states preferentially afforded naphthocyclobuta-pyrimidine derivative (3) via 1,2-addition. Upon 254 nm light-irradiation of 2 gave rise to the formation of benzopyrimidosemibullvalene (4) in fair yields. The reaction pathway for the formation of 4 is reasonably explained in the terms of di-π-methane rearrangement. Adduct 3 was newly converted to the corresponding barrelene derivative (2) by long-wave-length irradiation in the presence...

  10. Isolation and identification of new vasodilative substances in diesel exhaust particles

    Seki, Koh-ichi; Noya, Yoichi; Mikami, Yusuke; Taneda, Shinji; Suzuki, Akira K.; Kuge, Yuji; Ohkura, Kazue
    Goal, Scope, and Background: We recently developed a new isolation method for diesel exhaust particles (DEP), involving successive extraction with H2O, sodium bicarbonate, and sodium hydroxide, in which the sodium hydroxide extract was found to consist of phenolic components. Analysis of the extract revealed that vasodilative active nitrophenols are in DEP in significantly higher concentration than those estimated by an earlier method involving a combination of solvent extraction and repeated chromatography. These findings indicated that our new procedure offers a simple, efficient and reliable method for the isolation and identification of bioactive substances in DEP. This encouraged us to extend...

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