Publications by authors named "Shuichi Nishimura"

Determining the optimal treatment for patients with huge hepatocellular carcinoma (HCC) remains challenging. Although surgical resection is the preferred option, it is feasible only in selected cases. Transarterial chemoembolization is commonly used but often provides insufficient local control.

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  • A study analyzed 1,625 stool samples from children with diarrhea in Japan over four years (2018-2022) to detect human astroviruses (HAstVs) and other diarrheal viruses, finding HAstV in 8.6% of samples.
  • The prevalence of HAstVs varied by year, with a notable increase to 20.1% in 2021-2022, and a significant infection rate was observed in children aged 1-3 years.
  • The study identified multiple HAstV genotypes, including outbreaks of HAstV1 and MLB2 during the COVID-19 pandemic, and noted for the first time a mixed infection of HAstV1 and MLB1.
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The FilmArray® Gastrointestinal (GI) Panel is a modern, sensitive, and comprehensive stool testing technique for identifying common gastrointestinal pathogens, including viruses, bacteria, and parasites. Its increasing demand is due to ease of operation and automation. Pathogens, particularly viruses, undergo constant genetic evolution.

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Norovirus (NoV) genogroup II, polymerase type P31, capsid genotype 4, Sydney_2012 variant (GII.P31/GII.4_Sydney_2012) has been circulating at high levels for over a decade, raising the question of whether this strain is undergoing molecular alterations without demonstrating a substantial phylogenetic difference.

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An increasing trend of sapovirus (SaV) infections in Japanese children during 2009-2019, particularly after the introduction of the voluntary rotavirus (RV)-vaccination program has been observed. Herein, we investigated the epidemiological situation of SaV infections from 2019 to 2022 when people adopted a precautionary lifestyle due to the emergence of the COVID-19 pandemic, and RV vaccines had been implemented as routine vaccines. Stool samples were collected from children who attended outpatient clinics with acute gastroenteritis and analyzed by reverse transcriptase-polymerase chain reaction to determine viral etiology.

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Background: Human astrovirus (HAstV) infection is one of the leading causes of acute gastroenteritis in young children. The present study reports the outbreak of HAstV in children with acute gastroenteritis in Kyoto, Japan, during the COVID-19 pandemic, 2021.

Methods: A total of 61 stool samples were collected from children with acute gastroenteritis who visited a pediatric outpatient clinic in Maizuru city, Kyoto, Japan from July to October, 2021.

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  • Norovirus (NoV) is a leading cause of gastroenteritis, particularly in children under 5, but cases dropped significantly in Japan during the COVID-19 pandemic due to school closures.
  • In September 2021, an outbreak occurred in kindergartens and nurseries in Maizuru, Kyoto, where 26 stool samples tested positive for NoV GII, with most cases showing mild symptoms like vomiting.
  • The genomic analysis of the samples revealed mutations in the NoV GII.4 Sydney[P31] strain, highlighting the need for ongoing monitoring of NoV variants in Japan.
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  • * Researchers sequenced the complete RNA coding segments of a rare G9P[4] RVA strain found in a child's feces in Japan.
  • * The genomic profile of this strain, identified as G9-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2, reveals it contains DS-1-like genotype 2 genes and was isolated in 2013.
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Although two live oral rotavirus (RV) vaccines, Rotarix and RotaTeq, play a critical role toward reducing disease severity, hospitalization, and death rate in RV infections, regular monitoring of vaccine effectiveness (VE) is yet necessary because the segmented genome structure and reassortment capability of RVs pose considerable threats toward waning VE. In this study, we examined the VE by a test-negative study design against G9P[8]I2 strain during a seasonal outbreak in February-May, 2018, in an outpatient clinic in Kyoto Prefecture, Japan. It remains important because G9P[8]I2 strain remains partially heterotypic to these vaccines and predominating in post-vaccination era.

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Group A rotavirus is a leading cause of severe acute gastroenteritis worldwide. In this study, the first complete coding sequences of 11 RNA segments of human group A rotavirus G12P[8] in Japan were determined by an unbiased viral metagenomics. Its genomic constellation (VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes) was identified as G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1.

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  • - The study evaluated the use of gold markers implanted in the tissue around the prostate to improve the accuracy of setup during external beam radiation therapy (EBRT) after low-dose-rate (LDR) brachytherapy in 38 patients with prostate cancer.
  • - Analysis of over 175 CT imaging sessions showed that gold marker matching provided more precise measurements of setup errors compared to matching with pelvic bone, with statistically significant lower displacement values.
  • - The findings indicated that using gold markers results in smaller setup errors and reduces the optimal setup margin needed for effective treatment, supporting its use for enhanced accuracy in radiotherapy.
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Background: Diversity in group A rotavirus (RVA) strains after introduction of RV-vaccines remains an emerging concern worldwide. In this study, we investigated the prevalence and distribution of RVA genotypes in Japanese children with acute gastroenteritis (AGE) from 2015 to 2018. In addition, a comparison of the genotypes in pre-vaccination (2006-2012) and post-vaccination (2012-2018) periods was conducted to understand the impact of these vaccines on genotype distribution.

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Prostate-specific antigen nadir (nPSA) after radiotherapy for localized prostate cancer has been investigated as a predictor. However, nPSA usually requires several years, limiting its clinical utility. We investigated the significance of nPSA within 12 months (nPSA12) after low-dose-rate prostate brachytherapy (LDR-PB) or external beam radiotherapy (EBRT) on treatment outcomes.

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  • Rotavirus vaccines have been in use in Japan since 2011, and a study was conducted to observe the trends of group A rotavirus genotypes three years post-vaccination.
  • Out of 539 fecal samples from children with gastroenteritis collected between July 2014 and June 2015, 33% tested positive for rotavirus, with G1P[8] as the most common genotype.
  • The study noted an increase in G2P[4] detection rates after vaccine introduction, along with a significant amino acid change in its VP4 gene, suggesting the need for ongoing monitoring to understand if these changes relate to vaccination or natural variation.
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Background: Group A rotavirus (RVA) vaccines have been introduced in Japan since 2011. To investigate the molecular epidemiological traits of RVA during the transitional period of rotavirus vaccine implementation in Japan, this study was undertaken by following up three-decade long surveillance conducted in the same regions.

Methods: RVA were screened and genotyped by RT-PCR from diarrheal samples collected from non-hospitalized patients in six localities (Hokkaido, Tokyo, Shizuoka, Osaka, Kyoto, and Saga) during 2011 - 2014.

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Purpose: To analyze genitourinary toxicity by followup of the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) after prostate brachytherapy.

Methods And Materials: Six hundred eighty patients were treated with iodine-125 brachytherapy for localized prostate cancer. IPSS, OABSS, and two categories of IPSS questions (storage symptom score [IPSS-S] and voiding symptom score [IPSS-V]) were evaluated.

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Purpose: To evaluate the effectiveness of the single-energy metal artifact reduction (SEMAR) technique for improving the accuracy of I-125 seed identification in postimplant computed tomography (CT) after prostate brachytherapy.

Methods And Materials: Postimplant CT images of 40 patients treated with I-125 prostate brachytherapy were acquired. For all patients, 2 data sets were reconstructed, 1 with SEMAR algorithms (SEMAR image), and the other without SEMAR algorithms (non-SEMAR image).

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To evaluate the outcomes and feasibility of stereotactic body radiotherapy (SBRT) for cT3 and cT4N0M0 non-small cell lung cancer (NSCLC), 25 patients with localized primary NSCLC diagnosed as cT3 or cT4N0M0, given SBRT between May 2005 and July 2013, were analyzed. All patients had inoperable tumors. The major reasons for tumors being unresectable were insufficient respiratory function for curative resection, advanced age (>80 years old) or technically inoperable due to invasion into critical organs.

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A major cause of death in patients undergoing long-term domiciliary oxygen therapy (LTOT) is lung cancer progression. In our institution, we actively perform stereotactic body radiotherapy (SBRT) on patients with early-stage non-small-cell lung cancer undergoing LTOT. In this study, we retrospectively analyzed the treatment efficacy and safety of SBRT for patients with T1-3N0M0 non-small-cell lung cancer who had been prescribed LTOT for treatment of chronic obstructive pulmonary disease (COPD).

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A total of 29 Campylobacter jejuni and C. coli strains were isolated from Thai and Japanese children with diarrhea using the Loop-mediated Isothermal Amplification method. The samples were evaluated for mutations in gyrA and 23S rRNA in order to assess resistance against fluoroquinolones and macrolides, respectively.

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Human cosavirus (HCoSV) is a genus recently identified in the family Picornaviridae, which includes important pathogens in human health. The pathogenicity of HCoSV remains unclear. This study reports that an HCoSV strain, 10928/2012/JPN, was identified and collected from the stool sample of a child with acute gastroenteritis in Japan, with the detection rate of 0.

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We detected Campylobacter spp. in 5% (20/380) of diarrheal stool samples collected at an outpatient clinic in Kyoto using a commercial loop-mediated isothermal amplification (LAMP) kit with a fluorescent detection reagent after DNA extraction. The sensitivity and specificity were 100% in comparison with those of semi-nested PCR for the differentiation of Campylobacter jejuni and Campylobacter coli.

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Introduction: We investigated tolerable doses to organs at risk (OARs) in the mediastinum and pulmonary hilum following stereotactic body radiotherapy for centrally located lung tumors.

Methods: Between 2005 and 2012, 381 patients with lung tumors were treated with stereotactic body radiotherapy of 40 to 60 Gy in five fractions. From among these patients, we extracted those who received greater than 25 Gy irradiation to OARs and analyzed dosimetric factors in relation to grade 3 to 5 toxicities.

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Aim: To better define clinically relevant non-classic radiation-induced liver disease (RILD) following stereotactic body radiotherapy (SBRT) in patients with small hepatocellular carcinoma (HCC).

Methods: We retrospectively evaluated the influence of acute liver toxicities on fatal hepatic failure in HCC patients treated with SBRT. Between April 2006 and February 2012, 194 HCC were treated with SBRT.

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