Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
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Review
  • Hirofumi YASUE, Yuji MIZUNO, Eisaku HARADA
    2019 Volume 95 Issue 2 Pages 53-66
    Published: February 08, 2019
    Released: February 08, 2019
    JOURNALS FREE ACCESS FULL-TEXT HTML

    Coronary artery spasm (CAS) plays an important role in the pathogenesis of ischemic heart disease, including angina pectoris, myocardial infarction, and sudden death, occurring most often from midnight to early morning. CAS is prevalent among East Asians and is associated with an aldehyde dehydrogenase 2 (ALDH2)-deficient genotype (ALDH2*2) and alcohol flushing, which is prevalent among East Asians but is virtually non-existent in other populations. ALDH2 eliminates not only acetaldehyde but also other toxic aldehydes from lipid peroxidation and tobacco smoking, thereby protecting tissues and cells from oxidative damage. Risk factors for CAS include smoking and genetic polymorphisms including those of ALDH2*2, endothelial NO synthase, paraoxonase I, and interleukin-6. Accordingly, oxidative stress, endothelial dysfunction, and low-grade chronic inflammation play an important role in the pathogenesis of CAS, leading to increased coronary smooth muscle Ca2+ sensitivity through RhoA/ROCK activation and resultant hypercontraction. Ca-channel blockers blocking the intracellular entry of Ca2+ are specifically effective for treatment for CAS.

Original Articles
  • Maryam HASSANVAND, Yoshinori AKAISHI, Toshimitsu YAMAZAKI
    2019 Volume 95 Issue 2 Pages 67-74
    Published: February 08, 2019
    Released: February 08, 2019
    JOURNALS FREE ACCESS FULL-TEXT HTML

    We have been studying the (Σπ)0 mass distribution based on data from an old Hydrogen Bubble Chamber collected by Thomas et al. concerning the p, K0)Σπ reaction at pπ = 1.69 GeV/c. In this analysis we investigated the formation of the Λ(1405) state, using the Generalized Optical Theorem and T-matrix operator. We applied a combined transition operator, Tmix, which contains T21 (=TπΣ-KN) and T22 (= TπΣ−πΣ) due to the initial channel mixing in the Λ(1405) formation. We also considered a possible mixture of I = 0 and 1 in the wave function, as well as some background of the Σ(1385) population.

  • Yuuta IMOTO, Yuichi ABE, Kanji OKUMOTO, Mio OHNUMA, Haruko KUROIWA, Ts ...
    2019 Volume 95 Issue 2 Pages 75-85
    Published: February 08, 2019
    Released: February 08, 2019
    JOURNALS FREE ACCESS FULL-TEXT HTML

    GTP is an essential source of energy that supports a large array of cellular mechanochemical structures ranging from protein synthesis machinery to cytoskeletal apparatus for maintaining the cell cycle. However, GTP regulation during the cell cycle has been difficult to investigate because of heterogenous levels of GTP in asynchronous cell cycles and genetic redundancy of the GTP-generating enzymes. Here, in the unicellular red algae Cyanidioschyzon merolae, we demonstrated that the ATP–GTP-converting enzyme DYNAMO2 is an essential regulator of global GTP levels during the cell cycle. The cell cycle of C. merolae can be highly synchronized by light/dark stimulations to examine GTP levels at desired time points. Importantly, the genome of C. merolae encodes only two isoforms of the ATP–GTP-converting enzyme, namely DYNAMO1 and DYNAMO2. DYNAMO1 regulates organelle divisions, whereas DYNAMO2 is entirely localized in the cytoplasm. DYNAMO2 protein levels increase during the S-M phases, and changes in GTP levels are correlated with these DYNAMO2 protein levels. These results indicate that DYNAMO2 is a potential regulator of global GTP levels during the cell cycle.

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