28 results on '"Sota, Masahiro"'
Search Results
2. Eye Lens Radiation Dose to Nurses during Cardiac Interventional Radiology: An Initial Study.
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Yamada, Ayumi, Haga, Yoshihiro, Sota, Masahiro, Abe, Mitsuya, Kaga, Yuji, Inaba, Yohei, Suzuki, Masatoshi, Tada, Norio, Zuguchi, Masayuki, and Chida, Koichi
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RADIATION dosimetry ,CRYSTALLINE lens ,INTERVENTIONAL radiology ,RADIATION doses ,MEDICAL personnel - Abstract
Although interventional radiology (IVR) is preferred over surgical procedures because it is less invasive, it results in increased radiation exposure due to long fluoroscopy times and the need for frequent imaging. Nurses engaged in cardiac IVR receive the highest lens radiation doses among medical workers, after physicians. Hence, it is important to measure the lens exposure of IVR nurses accurately. Very few studies have evaluated IVR nurse lens doses using direct dosimeters. This study was conducted using direct eye dosimeters to determine the occupational eye dose of nurses engaged in cardiac IVR, and to identify simple and accurate methods to evaluate the lens dose received by nurses. Over 6 months, in a catheterization laboratory, we measured the occupational dose to the eyes (3 mm dose equivalent) and neck (0.07 mm dose equivalent) of nurses on the right and left sides. We investigated the relationship between lens and neck doses, and found a significant correlation. Hence, it may be possible to estimate the lens dose from the neck badge dose. We also evaluated the appropriate position (left or right) of eye dosimeters for IVR nurses. Although there was little difference between the mean doses to the right and left eyes, that to the right eye was slightly higher. In addition, we investigated whether it is possible to estimate doses received by IVR nurses from patient dose parameters. There were significant correlations between the measured doses to the neck and lens, and the patient dose parameters (fluoroscopy time and air kerma), implying that these parameters could be used to estimate the lens dose. However, it may be difficult to determine the lens dose of IVR nurses accurately from neck badges or patient dose parameters because of variation in the behaviors of nurses and the procedure type. Therefore, neck doses and patient dose parameters do not correlate well with the radiation eye doses of individual IVR nurses measured by personal eye dosimeters. For IVR nurses with higher eye doses, more accurate measurement of the radiation doses is required. We recommend that a lens dosimeter be worn near the eyes to measure the lens dose to IVR nurses accurately, especially those exposed to relatively high doses. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Evaluation of Lens Doses among Medical Staff Involved in Nuclear Medicine: Current Eye Radiation Exposure among Nuclear-Medicine Staff.
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Fujisawa, Masaki, Haga, Yoshihiro, Sota, Masahiro, Abe, Mitsuya, Kaga, Yuji, Inaba, Yohei, Suzuki, Masatoshi, Meguro, Taiichiro, Hosoi, Yoshio, and Chida, Koichi
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RADIATION exposure ,MEDICAL personnel ,NUCLEAR medicine ,POSITRON emission tomography ,SINGLE-photon emission computed tomography ,WILCOXON signed-rank test - Abstract
The International Commission on Radiological Protection has lowered the annual equivalent eye-lens dose to 20 mSv. Although occupational exposure can be high in nuclear medicine (NM) departments, few studies have been conducted regarding eye-lens exposure among NM staff. This study aimed to estimate the annual lens doses of staff in an NM department and identify factors contributing to lens exposure. Four nurses and six radiographers performing positron emission tomography (PET) examinations and four radiographers performing radioisotope (RI) examinations (excluding PET) were recruited for this study. A lens dosimeter was attached near the left eye to measure the 3-mm-dose equivalent; a personal dosimeter was attached to the left side of the neck to measure the 1-cm- and 70-µm-dose equivalents. Measurements were acquired over six months, and the cumulative lens dose was doubled to derive the annual dose. Correlations between the lens and personal-dosimeter doses, between the lens dose and the numbers of procedures, and between the lens dose and the amounts of PET drugs (radiopharmaceuticals) injected were examined. Wilcoxon's signed-rank test was used to compare lens and personal-dosimeter doses. The estimated annual doses were 0.93 ± 0.13 mSv for PET nurses, 0.71 ± 0.41 mSv for PET radiographers, and 1.10 ± 0.53 mSv for RI radiographers. For PET nurses, but not for PET or RI radiographers, there was a positive correlation between the numbers of procedures and lens doses and between amounts injected and lens doses. There was a significant difference between the lens and personal-dosimeter doses of PET nurses. The use of protective measures, such as shielding, should prevent NM staff from receiving lens doses > 20 mSv/year. However, depending on the height of the protective shield, PET nurses may be unable to assess the lens dose accurately using personal dosimeters. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
4. Development of a strictly regulated xylose-induced expression system in Streptomyces
- Author
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Noguchi, Yuji, Kashiwagi, Norimasa, Uzura, Atsuko, Ogino, Chiaki, Kondo, Akihiko, Ikeda, Haruo, and Sota, Masahiro
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- 2018
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5. Spatial Scattering Radiation to the Radiological Technologist during Medical Mobile Radiography.
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Otomo, Kazuki, Inaba, Yohei, Abe, Keisuke, Onodera, Mana, Suzuki, Tomohiro, Sota, Masahiro, Haga, Yoshihiro, Suzuki, Masatoshi, Zuguchi, Masayuki, and Chida, Koichi
- Subjects
MEDICAL radiography ,MEDICAL technologists ,X-ray equipment ,RADIATION exposure ,RADIATION ,CRYSTALLINE lens ,RADIATION protection ,MEDICAL digital radiography - Abstract
Mobile radiography allows for the diagnostic imaging of patients who cannot move to the X-ray examination room. Therefore, mobile X-ray equipment is useful for patients who have difficulty with movement. However, staff are exposed to scattered radiation from the patient, and they can receive potentially harmful radiation doses during radiography. We estimated occupational exposure during mobile radiography using phantom measurements. Scattered radiation distribution during mobile radiography was investigated using a radiation survey meter. The efficacy of radiation-reducing methods for mobile radiography was also evaluated. The dose decreased as the distance from the X-ray center increased. When the distance was more than 150 cm, the dose decreased to less than 1 μSv. It is extremely important for radiological technologists (RTs) to maintain a sufficient distance from the patient to reduce radiation exposure. The spatial dose at eye-lens height increases when the bed height is high, and when the RT is short in stature and abdominal imaging is performed. Maintaining sufficient distance from the patient is also particularly effective in limiting radiation exposure of the eye lens. Our results suggest that the doses of radiation received by staff during mobile radiography are not significant when appropriate radiation protection is used. To reduce exposure, it is important to maintain a sufficient distance from the patient. Therefore, RTs should bear this is mind during mobile radiography. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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6. Cryoprotective ability of betaine-type metabolite analogs during freezing denaturation of enzymes
- Author
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Nakagawa, Yuichi, Sota, Masahiro, and Koumoto, Kazuya
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- 2015
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7. Cloning and starch degradation profile of maltotriose-producing amylases from Streptomyces species
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Kashiwagi, Norimasa, Miyake, Michiru, Hirose, Shuichi, Sota, Masahiro, Ogino, Chiaki, and Kondo, Akihiko
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- 2014
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8. Host-specific factors determine the persistence of IncP-1 plasmids
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Sota, Masahiro and Top, Eva M.
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- 2008
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9. Adaptive plasmid evolution results in host-range expansion of a broad-host-range plasmid
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De Gelder, Leen, Williams, Julia J., Ponciano, Jose M., Sota, Masahiro, and Top, Eva M.
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Plasmids -- Properties ,Drug resistance in microorganisms -- Genetic aspects ,Bacterial transformation -- Evaluation ,Bacterial genetics -- Research ,Biological sciences - Abstract
Little is known about the range of hosts in which broad-host-range (BHR) plasmids can persist in the absence of selection for plasmid-encoded traits, and whether this 'long-term host range' can evolve over time. Previously, the BHR multidrug resistance plasmid pB10 was shown to be highly unstable in Stenotrophomonas maltophilia P21 and Pseudomonas putida H2. To investigate whether this plasmid can adapt to such unfavorable hosts, we performed evolution experiments wherein pB10 was maintained in strain P21, strain H2, and alternatingly in P21 and H2. Plasmids that evolved in P21 and in both hosts showed increased stability and decreased cost in ancestral host P21. However, the latter group showed higher variability in stability patterns, suggesting that regular switching between distinct hosts hampered adaptive plasmid evolution. The plasmids evolved in P21 were also equally or more stable in other hosts compared to pB10, which suggested true host-range expansion. The complete genome sequences of four evolved plasmids with improved stability showed only one or two genetic changes. The stability of plasmids evolved in H2 improved only in their coevolved hosts, not in the ancestral host. Thus a BHR plasmid can adapt to an unfavorable host and thereby expand its long-term host range.
- Published
- 2008
10. Isolation and characterization of naphthalene-catabolic genes and plasmids from oil-contaminated soil by using two cultivation-independent approaches
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Ono, Akira, Miyazaki, Ryo, Sota, Masahiro, Ohtsubo, Yoshiyuki, Nagata, Yuji, and Tsuda, Masataka
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- 2007
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11. Region-specific insertion of transposons in combination with selection for high plasmid transferability and stability accounts for the structural similarity of IncP-1 plasmids
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Sota, Masahiro, Tsuda, Masataka, Yano, Hirokazu, Suzuki, Haruo, Forney, Larry J., and Top, Eva M.
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Transposons -- Research ,Plasmids -- Research ,Plasmids -- Structure ,Operons -- Research ,Biological sciences - Abstract
The overall architecture of IncP-1 plasmids is very conserved in that the accessory genes are typically located in one or two specific regions: between oriV and trfA and between the tra and trb operons. Various hypotheses have been formulated to explain this, but none have been tested experimentally. We investigated whether this structural similarity is due to region-specific transposition alone or also is reliant on selection for plasmids with insertions limited to these two regions. We first examined the transposition of Tn21Km into IncP-1[beta] plasmid pBP136 and found that most Tn21Km insertions (67%) were located around oriV. A similar experiment using the oriV region of IncP-1[beta] plasmid pUO1 confirmed these results. We then tested the transferability, stability, and fitness cost of different pBP136 derivatives to determine if impairment of these key plasmid characters explained the conserved plasmid architecture. Most of the pBP136 derivatives with insertions in transfer genes were no longer transferable. The plasmids with insertions in the oriV-trfA and tra-trb regions were more stable than other plasmid variants, and one of these also showed a significantly lower fitness cost. In addition, our detailed sequence analysis of IncP-1 plasmids showed that Tn402/5053-like transposons are situated predominantly between the tra and trb operons and close to the putative resolution site for the ParA resolvase, a potential hot spot for those transposons. Our study presents the first empirical evidence that region-specific insertion of transposons in combination with selection for transferable and stable plasmids explains the structural similarity of IncP-1 plasmids.
- Published
- 2007
12. Plasmid pBP136 from Bordetella pertussis represents an ancestral form of IncP-1[beta] plasmids without accessory mobile elements
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Kamachi, Kazunari, Sota, Masahiro, Tamai, Yuji, Nagata, Noriyo, Konda, Toshifumi, Inoue, Toshiro, Top, Eva M., and Arakawa, Yoshichika
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Bordetella pertussis -- Genetic aspects ,Nucleotide sequence -- Research ,Genetic research ,Biological sciences - Abstract
The complete 41 268 bp nucleotide sequence of the IncP-1[beta] plasmid pBP136 from the human pathogen Bordetella pertussis, the primary aetiological agent of whooping cough, was determined and analysed. This plasmid carried a total of 46 ORFs: 44 ORFs corresponding to the genes in the conserved IncP-1[beta] backbone, and 2 ORFs similar to the XF1596 and XF1597 genes with unknown function of the plant pathogen Xylella fastidiosa. Interestingly, pBP136 had no accessory genes carrying genetic traits such as antibiotic or mercury resistance and/or xenobiotic degradation. Moreover, pBP136 had only two of the kle genes (kleAE) that have been reported to be important for the stability of IncP-1 plasmid in Pseudomonas aeruginosa. Phylogenetic analysis of the Kle proteins revealed that the KleA and KleE of pBP136 were phylogenetically distant from those of the present IncP-1 plasmids. In contrast, IncC1 and KorC, encoded upstream and downstream of the kle genes respectively, and the replication-initiation protein, TrfA, were closely related to those of the IncP-1[beta] 'R751 group'. These results suggest that (i) pBP136 without any apparent accessory genes diverged early from an ancestor of the present IncP-1[beta] plasmids, especially those of the R751 group, and (ii) the kle genes might be incorporated independently into the backbone region of the IncP-1 plasmids for their stable maintenance in various host cells. DOI 10.1099/mic.0.29056-0
- Published
- 2006
13. Genomic and functional analysis of the IncP-9 naphthalene-catabolic plasmid NAH7 and its transposon Tn4655 suggests catabolic gene spread by a tyrosine recombinase
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Sota, Masahiro, Yano, Hirokazu, Ono, Akira, Miyazaki, Ryo, Ishii, Hidenori, Genka, Hiroyuki, Top, Eva M., and Tsuda, Masataka
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Bacterial genetics -- Research ,Plasmids -- Research ,Bacteria, Aerobic -- Physiological aspects ,Biological sciences - Abstract
The naphthalene-catabolic (nah) genes on the incompatibility group P-9 (Ince-9) self-transmissible plasmid NAH7 from Pseudomonas putida G7 are some of the most extensively characterized genetic determinants for bacterial aerobic catabolism of aromatic hydrocarbons. In contrast to the detailed studies of its catabolic cascade and enzymatic functions, the biological characteristics of plasmid NAH7 have remained unclear. Our sequence determination in this study together with the previously deposited sequences revealed the entire structure of NAH7 (82,232 bp). Comparison of NAH7 with two other completely sequenced IncP-9 catabolic plasmids, pDTG1 and pWW0, revealed that the three plasmids share very high nucleotide similarities in a 39-kb region encoding the basic plasmid functions (the IncP-9 backbone). The backbone of NAH7 is phylogenetically more related to that of pDTG1 than that of pWW0. These three plasmids carry their catabolic gene clusters at different positions on the IncP-9 backbone. All of the NAH7-specified nah genes are located on a class II transposon, Tn4655. Our analysis of the Tn4655-encoded site-specific recombination system revealed that (i) a novel tyrosine recombinase, TnpI, catalyzed both the intra-and intermolecular recombination between two copies of the attI site, (ii) the functional attI site was located within a 119-bp segment, and (iii) the site-specific strand exchange occurred within a 30-bp segment in the 41-bp CORE site. Our results and the sequence data of other naphthalene-catabolic plasmids, pDTG1 and pND6-1, suggest a potential role of the TnpI-attI recombination system in the establishment of these catabolic plasmids.
- Published
- 2006
14. Structure of haloacetate-catabolic IncP-1[beta] plasmid pUO1 and genetic mobility of its residing haloacetate-catabolic transposon
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Sota, Masahiro, Kawasaki, Haruhiko, and Tsuda, Masataka
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Gene mutations -- Analysis ,Transposons -- Genetic aspects ,Plasmids ,Biological sciences - Abstract
The self-transmissible plasmid pUO1 from Delftia acidovorans strain B carries two haloacetate-catabolic transposons, TnHad1 and TnHad2, and the mer genes for resistance to mercury. The complete 67,066-bp sequence of pUO1 revealed that the mer genes were also carried by two Tn402/Tn5053-like transposons, Tn4671 and Tn4672, and that the pUO1 backbone regions shared 99% identity to those of the archetype IncP-1[beta] plasmid R751. Comparison of pUO1 with three other IncP-l[beta] plasmids illustrated the importance of transposon insertion in the diversity and evolution of this group of plasmids. Mutational analysis of the four outermost residues in the inverted repeats (IRs) of TnHad2, a Tn21-related transposon, revealed a crucial role of the second residue of its IRs in transposition.
- Published
- 2003
15. Using Mahalanobis distance to compare genomic signatures between bacterial plasmids and chromosomes
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Suzuki, Haruo, Sota, Masahiro, Brown, Celeste J., and Top, Eva M.
- Published
- 2008
16. Evaluation of novel X-ray protective eyewear in reducing the eye dose to interventional radiology physicians.
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Endo, Mime, Haga, Yoshihiro, Sota, Masahiro, Tanaka, Akiko, Otomo, Kazuki, Murabayashi, Yuuki, Abe, Mitsuya, Kaga, Yuji, Inaba, Yohei, Suzuki, Msatoshi, Meguro, Taiichiro, and Chida, Koichi
- Subjects
EYEGLASSES ,PHYSICIANS - Abstract
The new recommendation of the International Commission on Radiological Protection for occupational eye dose is an equivalent dose limit to the eye of 20 mSv year
–1 , averaged over a 5-year period. This recommendation is a drastic reduction from the previous limit of 150 mSv year–1 . Hence, it is important to protect physicians' eyes from X-ray radiation. Particularly in interventional radiology (IVR) procedures, many physicians use protective lead (Pb) glasses to reduce their occupational exposure. This study assessed the shielding effects of novel 0.07 mm Pb glasses. The novel glasses (XR-700) have Pb–acrylic lens molded in three dimensions. We studied the novel type of 0.07 mm Pb glasses over a period of seven consecutive months. The eye dose occupational radiation exposure of seven IVR physicians was evaluated during various procedures. All IVR physicians wore eye dosimeters (DOSIRIS™) close to the left side of the left eye. To calculate the shielding effects of the glasses, this same type of eye dosimeter was worn both inside and outside of the Pb lenses. The average shielding effect of the novel glasses across the seven physicians was 61.4%. Our results suggest an improved shielding effect for IVR physicians that use these glasses. No physician complained that the new glasses were uncomfortable; therefore comfort is not a problem. The lightweight glasses were acceptable to IVR physicians, who often must perform long procedures. Thus, the novel glasses are comfortable and reasonably protective. Based on the results of this study, we recommend that IVR physicians use these novel 0.07 mm Pb glasses to reduce their exposure. [ABSTRACT FROM AUTHOR]- Published
- 2021
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17. Surface wettability of silicon nanopillar array structures fabricated by biotemplate ultimate top-down processes.
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Takeuchi, Sou, Ohori, Daisuke, Sota, Masahiro, Ishida, Teruhisa, Li, Yiming, Tarng, Jenn-Hwan, Endo, Kazuhiko, and Samukawa, Seiji
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SILICON surfaces ,HYDROPHOBIC surfaces ,SILICON oxide films ,CONTACT angle ,SILICON oxide ,SOLID-liquid interfaces - Abstract
We fabricated high aspect ratio 10-nm Si nanopillar (NP) array structures with a few-tenths-nm-gap arranged by fusing biotemplate and neutral beam etching processes to investigate the wettability [e.g., contact angle (CA)] with and without surface silicon oxide film. The NP array with silicon native oxides in all gaps exhibited super-hydrophilicity due to the chemical liquid-solid interface interaction and larger surface area than the Si flat surface thanks to the NP structure. These phenomena can be explained by using the Wenzel model. In contrast, when we selectively removed the native oxide on Si NP surface with our radical treatment, a gap variation from 11 to 43 nm stably resulted in a CA of more than 96° (hydrophobicity) with a maximum of 115°. This can be explained by using the Cassie–Baxter model with a filling factor. Our findings demonstrate that controlled surface wettability can be achieved by combining our controllable gap silicon NP array structures and the surface with or without silicon native oxides. The gap of a Si NP fills with water due to the capillarity on a silicon native oxide, but on a pure stable silicon one with a defect-free surface, does not completely fill. We found that Si NP structures with controllable gaps exhibit a surface wettability ranging from super-hydrophilicity to high-hydrophobicity. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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18. Radiation eye dose to medical staff during respiratory endoscopy under X-ray fluoroscopy.
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Haga, Yoshihiro, Chida, Koichi, Kimura, Yuichiro, Yamanda, Shinsuke, Sota, Masahiro, Abe, Mitsuya, Kaga, Yuji, Meguro, Taiichiro, and Zuguchi, Masayuki
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RADIATION ,RADIATION doses ,RADIATION exposure ,BRONCHOSCOPY - Abstract
Although the clinical value of fluoroscopically guided respiratory endoscopy (bronchoscopy) is clear, there have been very few studies on the radiation dose received by staff during fluoroscopically guided bronchoscopy. The International Commission on Radiological Protection (ICRP) is suggesting reducing the occupational lens dose limit markedly from 150 to 20 mSv/year, averaged over defined periods of five years. The purpose of this study was to clarify the current occupational eye dose of bronchoscopy staff conducting fluoroscopically guided procedures. We measured the occupational eye doses (3-mm-dose equivalent, Hp(3)) of bronchoscopy staff (physicians and nurses) over a 6-month period. The eye doses of eight physicians and three nurses were recorded using a direct eye dosimeter, the DOSIRIS. We also estimated eye doses using personal dosimeters worn at the neck. The mean ± SD radiation eye doses (DOSIRIS) to physicians and nurses were 7.68 ± 5.27 and 2.41 ± 1.94 mSv/6 months, respectively. The new lens dose limit, 20 mSv/year, may be exceeded among bronchoscopy staff, especially physicians. The eye dose of bronchoscopy staff (both physicians and nurses) was underestimated when measured using a neck dosimeter. Hence, the occupational eye dose of bronchoscopy staff should be monitored. To reduce the occupational eye dose, we recommend that staff performing fluoroscopically guided bronchoscopy wear Pb glasses. correct evaluation of the lens dose [Hp(3)] using an eye dosimeter such as the DOSIRIS is necessary for bronchoscopy staff. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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19. Functional analysis of unique class II insertion sequence IS1071
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Sota, Masahiro, Yano, Hirokazo, Nagata, Yuji, Ohtsubo, Yoshiyuki, Genka, Haruhiko, Anbutsu, Hisashi, Kawasaki, Haruhiko, and Tsuda, Masataka
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Transposons -- Research ,Xenobiotics -- Research ,Plasmids -- Research ,Biological sciences - Abstract
A study was conducted on many catabolic plasmids often flanked by two copies of insertion sequence, IS1071, which were influenced by various xenobiotic-degrading genes. It was observed that only transposition at high frequencies was possible by IS1071 sequence and that IS1071had the functional features of the class II transposons.
- Published
- 2006
20. Metabolic engineering of Corynebacterium glutamicum for production of sunscreen shinorine.
- Author
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Tsuge, Yota, Kawaguchi, Hideo, Yamamoto, Shogo, Nishigami, Yoshiko, Sota, Masahiro, Ogino, Chiaki, and Kondo, Akihiko
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CORYNEBACTERIUM glutamicum ,GENE expression ,SUNSCREENS (Cosmetics) - Abstract
Ultraviolet-absorbing chemicals are useful in cosmetics and skin care to prevent UV-induced skin damage. We demonstrate here that heterologous production of shinorine, which shows broad absorption maxima in the UV-A and UV-B region. A shinorine producing Corynebacterium glutamicum strain was constructed by expressing four genes from Actinosynnema mirum DSM 43827, which are responsible for the biosynthesis of shinorine from sedoheptulose-7-phosphate in the pentose phosphate pathway. Deletion of transaldolase encoding gene improved shinorine production by 5.2-fold. Among the other genes in pentose phosphate pathway, overexpression of 6-phosphogluconate dehydrogenase encoding gene further increased shinorine production by 60% (19.1 mg/L). The genetic engineering of the pentose phosphate pathway in C. glutamicum improved shinorine production by 8.3-fold in total, and could be applied to produce the other chemicals derived from sedoheptulose-7-phosphate. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
21. Shifts in the host range of a promiscuous plasmid through parallel evolution of its replication initiation protein.
- Author
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Sota, Masahiro, Yano, Hirokazu, M Hughes, Julie, Daughdrill, Gary W, Abdo, Zaid, Forney, Larry J, and Top, Eva M
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PLASMIDS , *MOLECULAR evolution , *HOSTS (Biology) , *SHEWANELLA , *GENOMES , *NUCLEOTIDE sequence , *DNA replication , *PSEUDOMONAS aeruginosa - Abstract
The ability of bacterial plasmids to adapt to novel hosts and thereby shift their host range is key to their long-term persistence in bacterial communities. Promiscuous plasmids of the incompatibility group P (IncP)-1 can colonize a wide range of hosts, but it is not known if and how they can contract, shift or further expand their host range. To understand the evolutionary mechanisms of host range shifts of IncP-1 plasmids, an IncP-1β mini-replicon was experimentally evolved in four hosts in which it was initially unstable. After 1000 generations in serial batch cultures under antibiotic selection for plasmid maintenance (kanamycin resistance), the stability of the mini-plasmid dramatically improved in all coevolved hosts. However, only plasmids evolved in Shewanella oneidensis showed improved stability in the ancestor, indicating that adaptive mutations had occurred in the plasmid itself. Complete genome sequence analysis of nine independently evolved plasmids showed seven unique plasmid genotypes that had various kinds of single mutations at one locus, namely, the N-terminal region of the replication initiation protein TrfA. Such parallel evolution indicates that this region was under strong selection. In five of the seven evolved plasmids, these trfA mutations resulted in a significantly higher plasmid copy number. Evolved plasmids were found to be stable in four other naive hosts, but could no longer replicate in Pseudomonas aeruginosa. This study shows that plasmids can specialize to a novel host through trade-offs between improved stability in the new host and the ability to replicate in a previously permissive host. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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22. Novel organization of aromatic degradation pathway genes in a microbial community as revealed by metagenomic analysis.
- Author
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Suenaga, Hikaru, Koyama, Yoshinori, Miyakoshi, Masatoshi, Miyazaki, Ryo, Yano, Hirokazu, Sota, Masahiro, Ohtsubo, Yoshiyuki, Tsuda, Masataka, and Miyazaki, Kentaro
- Subjects
AROMATIC compounds ,PROKARYOTES ,DEOXYRIBOSE ,NUCLEIC acids ,ENZYMES - Abstract
Several types of environmental bacteria that can aerobically degrade various aromatic compounds have been identified. The catabolic genes in these bacteria have generally been found to form operons, which promote efficient and complete degradation. However, little is known about the degradation pathways in bacteria that are difficult to culture in the laboratory. By functionally screening a metagenomic library created from activated sludge, we had earlier identified 91 fosmid clones carrying genes for extradiol dioxygenase (EDO), a key enzyme in the degradation of aromatic compounds. In this study, we analyzed 38 of these fosmids for the presence and organization of novel genes for aromatics degradation. Only two of the metagenomic clones contained complete degradation pathways similar to those found in known aromatic compound-utilizing bacteria. The rest of the clones contained only subsets of the pathway genes, with novel gene arrangements. A circular 36.7-kb DNA form was assembled from the sequences of clones carrying genes belonging to a novel EDO subfamily. This plasmid-like DNA form, designated pSKYE1, possessed genes for DNA replication and stable maintenance as well as a small set of genes for phenol degradation; the encoded enzymes, phenol hydroxylase and EDO, are capable of the detoxification of aromatic compounds. This gene set was found in 20 of the 38 analyzed clones, suggesting that this ‘detoxification apparatus’ may be widespread in the environment. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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23. Characterization of a Class II Defective Transposon Carrying Two Haloacetate Dehalogenase Genes from Delfia acidovorans Plasmid pUO1.
- Author
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Sota, Masahiro, Endo, Masahiro, Nitta, Keiji, Kawasaki, Haruhiko, and Tsuda, Masataka
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HALOACID dehalogenase , *TRANSPOSONS - Abstract
Examines the characterization of haloacetate dehalogenase genes from Delftia acidovorans. Categorization of bacterial catabolic transposons; Nucleotide sequence of dehalogenase genes; Properties of transposons.
- Published
- 2002
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24. Hybrid Operating Room System for the Treatment of Thoracic and Abdominal Aortic Aneurysms: Evaluation of the Radiation Dose Received by Patients.
- Author
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Haga, Yoshihiro, Chida, Koichi, Sota, Masahiro, Kaga, Yuji, Abe, Mitsuya, Inaba, Yohei, Suzuki, Masatoshi, Meguro, Taiichiro, and Zuguchi, Masayuki
- Subjects
ABDOMINAL aortic aneurysms ,THORACIC aneurysms ,RADIATION doses ,ENDOVASCULAR surgery ,OPERATING rooms ,DIGITAL subtraction angiography - Abstract
In recent years, endovascular treatment of aortic aneurysms has attracted considerable attention as a promising alternative to traditional surgery. Hybrid operating room systems (HORSs) are increasingly being used to perform endovascular procedures. The clinical benefits of endovascular treatments using HORSs are very clear, and these procedures are increasing in number. In procedures such as thoracic endovascular aortic repair (TEVAR) and endovascular aortic repair (EVAR), wires and catheters are used to deliver and deploy the stent graft in the thoracic/abdominal aorta under fluoroscopic control, including DSA. Thus, the radiation dose to the patient is an important issue. We determined radiation dose indicators (the dose–area product (DAP) and air karma (AK) parameters) associated with endovascular treatments (EVAR and TEVAR) using a HORS. As a result, the mean ± standard deviation (SD) DAPs of TEVAR and EVAR were 323.7 ± 161.0 and 371.3 ± 186.0 Gy × cm
2 , respectively. The mean ± SD AKs of TEVAR and EVAR were 0.92 ± 0.44 and 1.11 ± 0.54 Gy, respectively. The mean ± SD fluoroscopy times of TEVAR and EVAR were 13.4 ± 7.1 and 23.2 ± 11.7 min, respectively. Patient radiation dose results in this study of endovascular treatments using HORSs showed no deterministic radiation effects, such as skin injuries. However, radiation exposure during TEVAR and EVAR cannot be ignored. The radiation dose should be evaluated in HORSs during endovascular treatments. Reducing/optimizing the radiation dose to the patient in HORSs is important. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
25. Complete Sequence Determination Combined with Analysis of Transposition/Site-specific Recombination Events to Explain Genetic Organization of IncP-7 TOL Plasmid pWW53 and Related Mobile Genetic Elements
- Author
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Yano, Hirokazu, Garruto, Christine E., Sota, Masahiro, Ohtsubo, Yoshiyuki, Nagata, Yuji, Zylstra, Gerben J., Williams, Peter A., and Tsuda, Masataka
- Subjects
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PLASMIDS , *TRANSPOSONS , *MOBILE genetic elements , *TOLUENE - Abstract
Abstract: Recent studies have indicated that the evolutionarily common catabolic gene clusters are loaded on structurally diverse toluene-catabolic (TOL) plasmids and their residing transposons. To elucidate the mechanisms supporting the diversification of catabolic plasmids and transposons, we determined here the complete 107,929 bp sequence of pWW53, a TOL plasmid from Pseudomonas putida MT53. pWW53 was found to belong to the IncP-7 incompatibility group that play important roles in the catabolism of several xenobiotics. pWW53 carried two distinct transposase-resolvase gene clusters (tnpAR modules), five short terminal inverted repeats (IRs), and three site-specific resolution (res) sites that are all typical of class II transposons. This organization of pWW53 suggested the four possible transposable regions, Tn4657 to Tn4660. The largest 86 kb region (Tn4657) spanned the three other regions, and Tn4657 and Tn4660 (62 kb) covered all of the 36 xyl genes for toluene catabolism. Our subsequent transposition experiments clarified that the three transposons, Tn4657 to Tn4659, indeed exhibit their transposability, and that pWW53 also generated another 37 kb toluene-catabolic transposon, Tn4656, which carried the two separated and inversely oriented segments of pWW53: the tnpRA-IR module of Tn4658 and a part of xyl gene clusters on Tn4657. The Tn4658 transposase was able to mediate the transposition of Tn4658, Tn4657, and Tn4656, while the Tn4659 transposase catalyzed only the transposition of Tn4659. Tn4656 was formed by the Tn4658 resolvase-mediated site-specific inversion between the two inversely oriented res sites on pWW53. These findings and comparison with other catabolic plasmids clearly indicate multiple copies of transposition-related genes and sites on one plasmid and their recombination activities contribute greatly to the diversification of plasmid structures as well as wide dissemination of the evolutionary common gene clusters in various plasmids. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
26. Evaluation of radiation dose to the lens in interventional cardiology physicians before and after dose limit regulation changes.
- Author
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Sagehashi K, Haga Y, Takahira S, Tanabe M, Nakamura M, Sota M, Kaga Y, Abe M, Tada N, and Chida K
- Abstract
In response to the International Commission on Radiological Protection (ICRP), which lowered the lens equivalent dose limit, Japan lowered the lens dose limit from 150 mSv/year to 100 mSv/5 years and 50 mSv/year, with this new rule taking effect on April 1, 2021. DOSIRIS® is a dosimeter that can accurately measure lens dose. Herein, we investigated lens dose in interventional cardiology physicians one year before and after the reduction of the lens dose limit using a neck dosimeter and lens dosimeter measurements. With an increase in the number of cases, both personal dose equivalent at 0.07 mm [Hp(0.07), neck dosimeter] and personal dose equivalent at 3 mm depth [Hp(3), lens dosimeter] increased for most of the physicians. The Hp(3) of the lens considering the shielding effect of the Pb glasses using lens dosimeter exceeded 20 mSv/year for two of the 14 physicians. Protection from radiation dose will become even more important in the future, as these two physicians may experience radiation dose exceeding 100 mSv/5 years. The average dose per procedure increased, but not significantly. There was a strong correlation between the neck dosimeter and lens dosimeter scores, although there was no significant change before and after the lens dose limit was lowered. This correlation was particularly strong for physicians who primarily treated patients. As such, it is possible to infer accurate lens doses from neck doses in physicians who primarily perform diagnostics. However, it is desirable to use a dosimeter that can directly measure Hp(3) because of the high lens dose., (© 2024 Society for Radiological Protection. Published on behalf of SRP by IOP Publishing Limited. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)
- Published
- 2024
- Full Text
- View/download PDF
27. Performance of the DOSIRIS™ eye lens dosimeter.
- Author
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Ishii H, Haga Y, Sota M, Inaba Y, and Chida K
- Subjects
- Equipment Design, Eye Protective Devices, Humans, Lens, Crystalline radiation effects, Occupational Exposure analysis, Radiation Dosimeters
- Abstract
Monitoring and protecting of occupational eye doses in interventional radiology (IR) are very important matters. DOSIRIS™ is the useful solution to estimate the 3 mm dose-equivalent (Hp(3)), and it can be worn behind lead glasses. And DOSIRIS™, adjustable according to 3 axes, it is ideally placed as close to the eye and in contact with the skin. So, DOSIRIS™ will be suitable eye lens dosimeter. However, the fundamental characteristics of the DOSIRIS™ in the diagnostic x-ray energy domain (including that of IR x-ray systems) remain unclear. Here, we evaluated the performance of the dosimeter in that energy range. As a result, the DOSIRIS™ has good fundamental characteristics (batch uniformity, dose linearity, energy dependence, and angular dependence) in the diagnostic x-ray energy domain. We conclude that the DOSIRIS™ has satisfactory basic performance for occupational eye dosimetry in diagnostic x-ray energy settings (including IR x-ray systems).
- Published
- 2019
- Full Text
- View/download PDF
28. Occupational eye dose in interventional cardiology procedures.
- Author
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Haga Y, Chida K, Kaga Y, Sota M, Meguro T, and Zuguchi M
- Subjects
- Humans, Nurses, Radiation Protection, Radiometry, Cardiologists, Eye radiation effects, Occupational Exposure adverse effects, Radiation Dosage, Radiation Exposure adverse effects, Radiology, Interventional
- Abstract
It is important to measure the radiation dose [3-mm dose equivalent, Hp(3)] in the eye. This study was to determine the current occupational radiation eye dose of staff conducting interventional cardiology procedures, using a novel direct eye dosimeter. We measured the occupational eye dose [Hp(3)] in physicians and nurses in a catheterization laboratory for 6-months. The eye doses [Hp(3)] of 12 physicians (9 with Pb glasses, 3 without), and 11 nurses were recorded using a novel direct eye dosimeter, the DOSIRIS
TM . We placed dosimeters above and under the glasses. We also estimated the eye dose [0.07-mm dose equivalent] using a neck personal dosimeter. The eye doses among interventional staff ranked in the following order: physicians without Pb glasses > physicians with Pb glasses > nurses. The shielding effect of the glasses (0.07-mm Pb) in a clinical setting was approximately 60%. In physicians who do not wear Pb glasses, the eye dose may exceed the new regulatory limit for IR staff. We found good correlations between the neck dosimeter dose and eye dosimeter dose (inside or outside glasses, R2 = 0.93 and R2 = 0.86, respectively) in physicians. We recommend that interventional physicians use an eye dosimeter for correct evaluation of the lens dose.- Published
- 2017
- Full Text
- View/download PDF
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