Koji Sakamoto

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Two RNA editing sites with cis-acting elements of moderate sequence identity are recognized by an identical site-recognition protein in tobacco chloroplasts

Nucleic Acids Research (2007)

Yukie Kobayashi Mitsuhiro Matsuo Koji Sakamoto Tatsuya Wakasugi K Yamada

The chloroplast genome of higher plants contains 20-40 C-to-U RNA editing sites, whose number and locations are diversified among plant species.Biochemical analyses using in vitro RNA editing systems with chloroplast extracts have suggested that there is one-to-one recognition between proteinous site recognition factors and their respective RNA editing sites, but their rigidness and generality are still unsettled.In this study, we addressed this question with the aid of an in vitro RNA editing system from tobacco chloroplast extracts and with UV-crosslinking experiments.We found that the ndhB-9 and ndhF-1 editing sites of tobacco chloroplast transcripts are both bound by the sitespecific trans-acting factors of 95 kDa.Crosscompetition experiments between ndhB-9 and ndhF-1 RNAs demonstrated that the 95 kDa proteins specifically binding to the ndhB-9 and ndhF-1 sites are the identical protein.The binding regions of the 95 kDa protein on the ndhB-9 and ndhF-1 transcripts showed 60% identity in nucleotide sequence.This is the first biochemical demonstration that a site recognition factor of chloroplast RNA editing recognizes plural sites.On the basis of this finding, we discuss how plant organellar RNA editing sites have diverged during evolution.

NdhF

10.1093/nar/gkm1026

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Citations (34)

Pharmacokinetics of Amikacin and Cephalothin in Bedridden Elderly Patients

The Journal of Clinical Pharmacology (1982)

Hajime Yasuhara Shinichi Kobayashi Koji Sakamoto Kazuya Kamijo

Abstract: The pharmacokinetics of amikacin (5.5 mg/kg intramuscularly) and cephalothin (1000 mg/body intravenously) in bedridden elderly patients were studied in comparison with those in healthy volunteers. The eliminations of amikacin and cephalothin from the plasma followed the course of a one‐compartment open model. For amikacin, five healthy volunteers, elimination rate constant K el was 0.396 hr −1 biologic half‐life t ½ was 1.80 hour, volume of distribution V d was 0.201 l./kg; in five bedridden elderly patients, K el was 0.208 hr −1 , t ½ was 3.55 hours, V d was 0.376 l./kg. Cumulative renal excretion of amikacin in 8 hours was 44 per cent of the total dose in bedridden elderly patients and 69 per cent in healthy volunteers. For cephalothin, in seven healthy volunteers, K el was 0.0353 min −1 , t ½ was 19.7 min, V d was 0.176 l./kg; in four bedridden elderly patients, K el was 0.0127 min −1 , t ½ was 56.4 min, V d was 0.283 l./kg. Cumulative renal excretion of cephalothin reached a plateau by 4 hours of 40.8 per cent of the total dose in bedridden elderly patients and of 56.7 per cent in healthy volunteers. These results suggest that in bedridden elderly patients decreased renal excretion of amikacin and cephalothin is related to decreased renal function and an increased V d .

Amikacin

Impaired renal function

10.1002/j.1552-4604.1982.tb02693.x

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Citations (16)

651 Ablation of disintegrin and metalloproteinase 10 (ADAM10) disrupts hair follicle immune privilege

Journal of Investigative Dermatology (2019)

Koji Sakamoto T. Kobayashi Benjamin Voisin D. Kim Kazutaka Nagao

ADAM10

Immune privilege

10.1016/j.jid.2019.03.727

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Citations (0)

COVID-19-Triggered Acute Exacerbation of IPF, an Underdiagnosed Clinical Entity With Two-Peaked Respiratory Failure: A Case Report and Literature Review

Frontiers in Medicine (2022)

Yosuke Goto Koji Sakamoto Jun Fukihara Atsushi Suzuki Norihito Omote

Because severe coronavirus disease 2019 (COVID-19) affects the respiratory system and develops into respiratory failure, patients with pre-existing chronic lung disorders, such as idiopathic pulmonary fibrosis (IPF), are thought to be at high risk of death. Patients with IPF often suffer from a lethal complication, acute exacerbation (AE), a significant part of which is assumed to be triggered by respiratory viral infection. However, whether mild to moderate COVID-19 can trigger AE in patients with IPF remains unknown. This is the case report of a 60-year-old man with a 4-year history of IPF who successfully recovered from moderate COVID-19 but subsequently developed more severe respiratory failure, which was considered to be a COVID-19-triggered acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF). It is important to be aware of the risk of AE-IPF after COVID-19 and to properly manage this deadly complication of IPF. Recent literature reporting cases with chronic interstitial lung diseases which developed respiratory failure by complications with COVID-19 is also reviewed and discussed.

Diffuse alveolar damage

10.3389/fmed.2022.815924

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Citations (10)

Survival Analysis and Immunohistochemical Study of HER-2 and AR (Androgen Receptor) Expression in Salivary Duct Carcinoma

Nippon Jibiinkoka Gakkai Kaiho (2013)

Kuninori Otsuka Yorihisa Imanishi Noboru Habu Yoichiro Sato Seiji Shigetomi

背景: 唾液腺導管癌 (SDC) はその罹患率の低さゆえに多数症例による臨床像の検討が不十分なままで, 補助全身療法を含め有効な治療法の標準化がいまだ困難である. 目的: SDCの予後因子の解析と治療標的候補分子の発現の評価方法: 1996年から2010年までの15年間に慶應義塾大学耳鼻咽喉科で初回治療を行ったSDC16症例を対象に, 臨床統計学的および免疫組織化学的検討を行った. 結果: 全体の無病3年生存率は29.2%, 疾患特異的3年生存率は72.7%であった. 年齢, 性別, T分類, N分類, Stage分類, 原発部位, 多型腺腫由来の有無の各臨床病理学的因子の影響を検討した結果, 単変量解析ではDFSにおいて年齢, T分類, Stage分類に有意差が認められ, 多変量解析により年齢とT分類が本疾患の独立予後因子と考えられた. HER-2, エストロゲン受容体 (ER), プロゲステロン受容体 (PR), アンドロゲン受容体 (AR) およびMIB-1 (index>20%) の発現陽性率は各々50%, 6%, 13%, 100%, 69%で, 各分子の発現と予後との相関は認められなかった. 結語: 遠隔転移が生存率向上の最大の障壁であるSDCにおいて, 高い陽性率を示すHER-2とARは全身療法の治療標的候補になり得る. 各々の陽性症例に対する抗HER-2療法や抗アンドロゲン療法の有効性を評価するためには, 今後多施設共同研究体制の構築が不可欠である.

Salivary duct carcinoma

10.3950/jibiinkoka.116.1024

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Citations (10)

Application of the Porapak Q Column Extraction Method for Tomato Flavor Volatile Analysis

Journal of Agricultural and Food Chemistry (2002)

Chamorn Maneerat Yasuyoshi Hayata Hiroshi Kozuka Koji Sakamoto Yutaka OSAJIMA

The Porapak Q column method (PQM) was compared to the method of simultaneous distillation extraction (SDE) under reduced pressure for extraction of the volatile compounds produced by tomato cv. Momotaro. The PQM was found to be effective at trapping and isolating many low and high boiling point volatile compounds and at producing the very desirable natural ripe tomato flavor of extracts. The SDE method was less effective in isolating the higher boiling point volatile compounds and caused deterioration of volatile compounds due to the heating process that takes place during extraction, resulting in an unpleasant boiled green tomato flavor of extracts. The advantages of using the PQM are its simplicity and its high efficiency in isolating many volatile compounds from nonvolatile materials at room temperature. A total of 367 volatile compounds were isolated by the PQM. Of these, hexanal, (Z)-3-hexenal, (E)-2-hexenal, 2- and 3-methylbutanol, and 2-phenylethanol were relatively more abundant than other compounds and (Z)-3-hexenal showed the highest relative amount.

Boiling point

10.1021/jf011626r

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Citations (23)

S-Methylmethionine Sulfonium in Fruits of Citrus Hybrids

Bioscience Biotechnology and Biochemistry (1996)

Koji Sakamoto Atsuhiko Inoue Muneichi NAKATANI Hiroshi Kozuka Hideaki Ohta

The S-methylmethionine sulfonium (MMS) concentrations in fruits of citrus hybrids were measured, and found to increase during ripening of the fruit. However, three of eleven hybrids of ‘Seto unshiu’ crossed with ‘Morita ponkan’ and four of 9 hybrids of ‘Murcott’ tangor crossed with ‘Seto unshiu’ had low MMS concentrations even at late harvest stage. Crossbreeding is useful in producing new citrus fruits that have juices with the desirable characteristics of their parents without formation of dimethyl sulfide which is an off-flavor.

Citrus unshiu

Sulfonium

10.1271/bbb.60.1486

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Citations (6)

Blood DNA virome associates with autoimmune diseases and COVID-19

Nature Genetics (2025)

Noah Sasa Shohei Kojima Rie Koide Takanori Hasegawa Ho Namkoong

Aberrant immune responses to viral pathogens contribute to pathogenesis, but our understanding of pathological immune responses caused by viruses within the human virome, especially at a population scale, remains limited. We analyzed whole-genome sequencing datasets of 6,321 Japanese individuals, including patients with autoimmune diseases (psoriasis vulgaris, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), pulmonary alveolar proteinosis (PAP) or multiple sclerosis) and coronavirus disease 2019 (COVID-19), or healthy controls. We systematically quantified two constituents of the blood DNA virome, endogenous HHV-6 (eHHV-6) and anellovirus. Participants with eHHV-6B had higher risks of SLE and PAP; the former was validated in All of Us. eHHV-6B-positivity and high SLE disease activity index scores had strong correlations. Genome-wide association study and long-read sequencing mapped the integration of the HHV-6B genome to a locus on chromosome 22q. Epitope mapping and single-cell RNA sequencing revealed distinctive immune induction by eHHV-6B in patients with SLE. In addition, high anellovirus load correlated strongly with SLE, RA and COVID-19 status. Our analyses unveil relationships between the human virome and autoimmune and infectious diseases. Analysis of the blood DNA virome in patients with COVID-19 and autoimmune disease associates endogenous HHV-6 (eHHV-6) and high anellovirus load with increased disease risk, most notably for systemic lupus erythematosus. eHHV-6 carriers show a distinct immune response.

Human virome

10.1038/s41588-024-02022-z

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Citations (1)

NIPPON SHOKUHIN KOGYO GAKKAISHI (1981)

Yoshimasa Yamano Koji Sakamoto Junko Sonobe Eizo Miki

極性脂質であるレシチンを0～1.2%,丸大豆,脱脂大豆豆乳,及び11Sタンパク水溶液に添加して調製したゲルの硬さは,レシチン濃度に対してほとんど変化せず,本試料のような多成分系では,極性脂質のマクロな物性への影響は現われないと考えられた。粉末油脂の主成分である,パーム油,カゼインソーダ及びデキストリンのゲルの硬さへの効果は,それぞれ3.5%まで増加しそれ以上は一定,濃度の増加とともに直線的に増大,及び濃度の増加とともに直線的に減少という結果になり,実際の粉末油脂の3成分含有比におけるゲルの硬さの和は,始めやや増大,のちやや減少するという結果となり,粉末油脂濃度とともにぼほ直線的に増大するという現象とはかなり異なる様相を示した。

10.3136/nskkk1962.28.12_650

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Citations (1)

Inhibitory Actions of Glucosamine on Platelet Functions

Ensho Saisei (2003)

Jian Hua Shiori Suguro Yuko Tsutsumi‐Ishii Kazuhisa Iwabuchi Koji Sakamoto

Glucosamine, an amino monosaccharide naturally occurring in the connective and cartilage tissues, contributes to maintaining the strength, flexibility and elasticity of these tissues. In recent years, glucosamine has been widely used to treat osteoarthritis in humans, because glucosamine increases proteoglycan synthesis and prevents cartilage degradation. Recently, we have revealed that glucosamine suppresses neutrophil functions, thereby possibly exhibiting anti-inflammatory actions in arthritis. Alternatively, we have found that glucosamine improves the fluidity of blood (hemorheology) analyzed by microchannel array. Therefore, in this study, we evaluated the effects of glucosamine on the functions of platelets, which play an essential role in thrombosis. Glucosamine suppressed platelet aggregation in response to ADP-stimulation, but not collagen-and thrombin-stimulation. Furthermore, glucosamine inhibited the extracellular release of granular constituents (ATP and platelet factor 4), and the production of thromboxane from ADP-stimulated platelets. In addition, glucosamine significantly inhibited the mobilization of intracellular calcium and the phosphorylation of Syk associated with platelet activation. Together these observations suggest that glucosamine suppresses platelet aggregation via the inhibition of calcium mobilization, Syk phosphorylation, granular content release and thromboxane production. Thus, glucosamine may have preventive effects on thrombosis by its suppressive actions on platelet functions.

10.2492/jsir.23.164

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Citations (2)