The Keio Journal of Medicine
Online ISSN : 1880-1293
Print ISSN : 0022-9717
ISSN-L : 0022-9717
Current issue
Displaying 1-5 of 5 articles from this issue
REVIEW
  • Deokho Lee, Yukihiro Miwa, Hiromitsu Kunimi, Mari Ibuki, Chiho Shoda, ...
    Article type: REVIEW
    2022 Volume 71 Issue 1 Pages 1-12
    Published: 2022
    Released on J-STAGE: March 25, 2022
    Advance online publication: April 10, 2021
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    The uncontrolled growth of blood vessels is a major pathological factor in human eye diseases that can result in blindness. This effect is termed ocular neovascularization and is seen in diabetic retinopathy, age-related macular degeneration, glaucoma and retinopathy of prematurity. Current treatments for these diseases include laser photocoagulation, topical injection of corticosteroids, intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents and vitreoretinal surgery. Although strategies to inhibit VEGF have proved to be dramatically successful in some clinical studies, there remains the possibility of significant adverse effects regarding the blockade of crucial physiological roles of VEGF and the invasive nature of the treatments. Moreover, it is evident that other pro-angiogenic factors also play important roles in the development of these diseases, as seen in cases in which anti-VEGF therapies have failed. Therefore, new types of effective treatments are required. In this review, we discuss a promising strategy for the treatment of ocular neovascular diseases, i.e., the inhibition of hypoxia-inducible factor (HIF), a master regulator of angiogenesis. We also summarize promising recently investigated HIF inhibitors as treatments for ocular diseases. This review will facilitate more comprehensive approaches to understanding the protective aspects of HIF inhibition in the prevention of ocular diseases.

ORIGINAL ARTICLES
  • Isao Kamae
    Article type: ORIGINAL ARTICLE
    2022 Volume 71 Issue 1 Pages 13-20
    Published: 2022
    Released on J-STAGE: March 25, 2022
    Advance online publication: February 02, 2022
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    In this study, the complicated reasoning and processes inherent in diagnostic testing were analyzed, and a mathematical theory was developed for effectively stopping the transmission of infection in the context of coronavirus disease 2019 (COVID-19). As a result of this work, a new formula was developed for the “boundary condition for contagion containment,” which, based on a horizontal transmission model, gives the lower limit of sensitivity for a diagnostic test to stop the virus spreading. Two parameters are considered in the model: the level of transmission and the effective reproduction number. In example computations, the formula indicated that a one-off polymerase chain reaction-based test with a sensitivity of 85% would not be sufficient to contain highly contagious infections such as the Delta variant of SARS-CoV-2, which would likely require a sensitivity close to 100% for its containment. Furthermore, a cascade judgment system for multiple tests was proposed and examined as a form of triplet test system. This approach can enhance the accuracy of COVID-19 testing up to the minimum level needed to stop the virus spreading. The theory developed in this study will not only contribute as an academic exercise, but also be useful for making evidence-based decisions on public policy for pandemic control.

  • Ho Lee, Tatsuya Suzuki, Yohei Okada, Hiromu Tanaka, Satoshi Okamori, H ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 71 Issue 1 Pages 21-30
    Published: 2022
    Released on J-STAGE: March 25, 2022
    Advance online publication: November 11, 2021
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    Coronavirus disease 2019 (COVID-19) was first reported in Wuhan, China, in December 2019 as an outbreak of pneumonia of unknown origin. Previous studies have suggested the utility of chest computed tomography (CT) in the diagnosis of COVID-19 because of its high sensitivity (93%–97%), relatively simple procedure, and rapid test results. This study, performed in Japan early in the epidemic when COVID-19 prevalence was low, evaluated the diagnostic accuracy of chest CT in a population presenting with lung diseases having CT findings similar to those of COVID-19. We retrospectively included all consecutive patients (≥18 years old) presenting to the outpatient department of Keio University Hospital between March 1 and May 31, 2020, with fever and respiratory symptoms. We evaluated the performance of diagnostic CT for COVID-19 by using polymerase chain reaction (PCR) results as the reference standard. We determined the numbers of false-positive (FP) results and assessed the clinical utility using decision curve analysis. Of the 175 patients, 22 were PCR-positive. CT had a sensitivity of 68% and a specificity of 57%. Patients with FP results on CT diagnosis were mainly diagnosed with diseases mimicking COVID-19, e.g., interstitial lung disease. Decision curve analysis indicated that the clinical utility of CT imaging was limited. The diagnostic performance of CT for COVID-19 was inadequate in an area with low COVID-19 prevalence and a high prevalence of other lung diseases with chest CT findings similar to those of COVID-19. Considering this insufficient diagnostic performance, CT findings should be evaluated in the context of additional medical information to diagnose COVID-19.

ABSTRACTS
  • Katalin Karikó
    Article type: ABSTRACT
    2022 Volume 71 Issue 1 Pages 31
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL FREE ACCESS

    Messenger RNA was discovered in 1961 and it took 60 years until the first mRNA became FDA-approved product in the form of COVID-19 mRNA vaccine. During those years a lot of progress has been made by hundreds of scientists. It was 1978 when the first-time isolated mRNA delivered into mammalian cells produced the encoded protein. In vitro transcription introduced in 1984 made it possible to generate any desired mRNA from the encoding plasmid using phage RNA polymerases. In the early 90s mRNA was used for therapy as well as vaccine against infectious diseases and cancer. Inflammatory nature of the mRNAs limited their in vivo use. Replacing uridine with pseudouridine made the mRNA non-immunogenic, more stable and highly translatable. Delivery of the lipid nanoparticle-formulated nucleoside-modified mRNA encoding viral antigens became a platform for effective vaccine. Labile nature of the mRNA is ideal for transient production of the viral antigen, to generate effective antibody and cellular immune response. The mRNA platform is revolutionizing the delivery of effective and safe vaccines, therapeutics and gene therapies.

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  • Osamu Nureki
    Article type: ABSTRACT
    2022 Volume 71 Issue 1 Pages 32
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL FREE ACCESS FULL-TEXT HTML

    Membrane and membrane-spanning proteins, and non-coding RNA are biomolecules to play central roles in beginning of life and distinguishing higher-order eukaryotes. We have determined the structures of membrane protein-lipids complexes and non-coding RNA-protein complexes by X-ray crystallography and Cryo-EM single particle analysis, and combined with complementary functional analyses, elucidate their molecular mechanisms at atomic resolutions, to promote creating drugs and medical technologies with two venture companies.

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