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69
result(s) for
"Tanaka, Nobukazu"
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Effect of anti-scatter grids on the image improvement factor in digital radiography for various phantom thicknesses and irradiation fields
2023
Digital radiography (DR) is used to acquire digital images with a consistent image brightness under different exposures and in the presence of various anti-scatter grids. This study effectively evaluates the image improvement factor and the conventional physical imaging properties, such as grid selectivity, contrast improvement ratio, and grid exposure factor. Various grids and acrylic phantoms of thicknesses 20 cm and 12 cm were used in this evaluation to simulate the pelvis and lumbar spine, and the cervical spine, respectively. Applied irradiation fields were adjusted according to the simulated body parts. Eight grids (four at 40 cm−1 strip frequency with grid ratios of 6:1, 8:1, 10:1, and 12:1, and four at 60 cm−1 strip frequency with grid ratios of 8:1, 10:1, 12:1, and 14:1) were used in this study. The grid selectivity, contrast improvement ratio, and grid exposure factor increased with higher grid ratios. At a constant grid ratio, these three parameters exhibited higher values at lower strip frequency (40 cm−1) than at higher strip frequency (60 cm−1). The change in the image improvement factor of the simulated cervical spine with respect to the grid was smaller than those of the simulated pelvis and lumbar spine. Our results suggested that the image improvement factor is a useful index for selecting grids according to object thickness at a constant exposure in DR systems.
Journal Article
Functional characterization of a new grapevine MYB transcription factor and regulation of proanthocyanidin biosynthesis in grapes
by
Matsumura, Hideo
,
Tanaka, Nobukazu
,
Numata, Mineyo
in
Amino Acid Sequence
,
Arabidopsis
,
Berries
2014
A new regulator of proanthocyanidin (PA) biosynthesis in grapes was found by screening genes coordinately expressed with PA accumulation under different light conditions using a substantially improved method of serial analysis of gene expression (SuperSAGE). This R2R3-MYB transcription factor, VvMYBPAR, shows high protein sequence similarity with PA biosynthesis-regulating plant MYBs, such as VvMYBPA2 and TRANSPARENT TESTA2. Its transcript levels were relatively high in the skins of young berries, whereas the levels were higher in the seeds and at a maximum around veraison. In addition to its response to modified light conditions, the gene responded to abscisic acid application in the skins of cultured berries. Among the PA-specific branch genes, this transcript profile was not correlated with that of VvANR and VvLAR1 but was closely related to that of VvLAR2, suggesting different regulation of PA-specific branch genes from that of a known PA regulator, VvMYBPA2. The PA-specific regulation of VvMYBPAR was confirmed by VvMYBPAR constitutive expression in Arabidopsis in which the transgene specifically induced PA biosynthetic genes and resulted in PA accumulation in plants grown on sucrose-supplemented media to induce anthocyanin synthesis. A transient reporter assay using grapevine cells showed that VvMYBPAR activated the promoters on PA-specific branch genes and candidate genes associated with modification and transport of monomeric PA precursors, as well as the promoters of VvCHS3 and in tVvF3′5′Hd he common flavonoid pathway, but not that of VvUFGT on the anthocyanin-specific branch. This new factor suggests the polygenic regulation of PA biosynthesis in grapes by closely related MYB transcription factors.
Journal Article
Meta-analysis of transcriptomic responses to biotic and abiotic stress in tomato
by
Ashrafi-Dehkordi, Elham
,
Tanaka, Nobukazu
,
Alemzadeh, Abbas
in
Abiotic and biotic stresses
,
Abiotic stress
,
Agricultural biotechnology
2018
A wide range of biotic stresses (BS) and abiotic stresses (AS) adversely affect plant growth and productivity worldwide. The study of individual genes cannot be considered as an effective approach for the understanding of tolerance mechanisms, since these stresses are frequent and often in combination with each other, and a large number of genes are involved in these mechanisms. The availability of high-throughput genomic data has enabled the discovery of the role of transcription factors (TFs) in regulatory networks. A meta-analysis of BS and AS responses was performed by analyzing a total of 391 microarray samples from 23 different experiments and 2,336 differentially expressed genes (DEGs) involved in multiple stresses were identified. We identified 1,862 genes differentially regulated in response to BS was much greater than that regulated by AS, 835 genes, and found 15.4% or 361 DEGs with the conserved expression between AS and BS. The greatest percent of genes related to the cellular process (>76% genes), metabolic process (>76% genes) and response to stimulus (>50%). About 4.2% of genes involved in BS and AS responses belonged to the TF families. We identified several genes, which encode TFs that play an important role in AS and BS responses. These proteins included Jasmonate Ethylene Response Factor 1 (JERF1), SlGRAS6, MYB48, SlERF4, EIL2, protein LATE ELONGATED HYPOCOTYL (LHY), SlERF1, WRKY 26, basic leucine zipper TF, inducer of CBF expression 1-like, pti6, EIL3 and WRKY 11. Six of these proteins, JERF1, MYB48, protein LHY, EIL3, EIL2 and SlGRAS6, play central roles in these mechanisms. This research promoted a new approach to clarify the expression profiles of various genes under different conditions in plants, detected common genes from differentially regulated in response to these conditions and introduced them as candidate genes for improving plant tolerance through genetic engineering approach.
Journal Article
Novel Prognostic Score for recurrent or metastatic head and neck cancer patients treated with Nivolumab
2021
Although several prognostic factors in nivolumab therapy have been reported in recurrent or metastatic head and neck cancer (RM-HNC) patients, these factors remain controversial. Here, we conducted a multicenter retrospective cohort study to investigate the impact of clinico-hematological factors on survival in RM-HNC patients treated with nivolumab. We reviewed 126 RM-HNC patients from seven institutes. We evaluated the prognostic effects of clinico-hematological factors on survival. The median overall survival (OS) was 12.3 months, and the 1 year-OS rate was 51.2%. Patients without immune-related adverse events, lower relative eosinophil count, worse best overall response, higher performance status, and higher modified Glasgow Prognostic Score had worse survival. The score, generated by combining these factors, was associated with survival. Patients with score of 4–5 had worse survival than those with score of 2–3 and 0–1 [adjusted HR for PFS: score of 4–5, 7.77 (3.98–15.15); score of 2–3, 3.44 (1.95–6.06), compared to score of 0–1], [adjusted HR for OS: score of 4–5, 14.66 (4.28–50.22); score of 2–3, 7.63 (2.29–25.37), compared to score of 0–1]. Our novel prognostic score utilizing clinico-hematological factors might be useful to establish an individual treatment strategy in RM-HNC patients treated with nivolumab therapy.
Journal Article
Clinical impact of a dose-escalation strategy for lenvatinib in differentiated thyroid cancer
2024
Background Treatment options for patients with differentiated thyroid cancer (DTC) who experience disease progression on lenvatinib treatment are limited. Although dose escalation of treatment with tyrosine kinase inhibitors at disease progression has been reported across cancer types, clinical significance in patients with DTC has not been investigated.MethodsWe retrospectively reviewed patients with DTC who experienced disease progression on lenvatinib treatment from September 2011 to June 2022. We compared subjects who received dose-escalation treatment with standard treatment of termination at the time of initial disease progression. The escalated dose was decided by referencing to the previous effective and tolerated dose.ResultsThirty-three patients were identified, 15 with dose escalation and 18 with lenvatinib termination. In both groups, the starting dose of lenvatinib was 24 mg/day, and the median dose at initial disease progression was 10 mg/day. In the former, the median dose escalation was 6 mg/day (range: 4–12). Objective response rate, clinical benefit rate by escalation, and median treatment duration of the dose-escalation phase were 13.3%, 73.3%, and 9.9 months (95% confidence interval [CI] 5.71–27.6), respectively. Median overall survival from initial disease progression was significantly longer in the dose-escalation group (median OS: 20.4 months [95% CI 7.0–NA] vs. 3.9 months [95% CI 1.7–7.9], log-rank p-value; 0.0004, hazard ratio; 0.22 [95% CI 0.09–0.55]). There were no grade 5 adverse events, and one patient discontinued due to a grade 3 lung abscess.ConclusionThe dose-escalation strategy appears to be a safe and effective treatment option after disease progression in patients treated with lenvatinib for DTC.
Journal Article
Relationship between daily swallowing frequency and pneumonia in patients with severe cerebral palsy
by
Sakai, Takayoshi
,
Fujii, Nami
,
Obana, Aya
in
Aspiration pneumonia
,
Bacterial pneumonia
,
Cerebral palsy
2022
Background
Aspiration pneumonia is a major complication that occurs in patients with severe cerebral palsy and is associated with their survival prognosis, necessitating appropriate assessment and response. We focused on swallowing frequency as an index of daily swallowing function due to the difficulty in evaluating the risk of pneumonia. The swallowing motion protects the airway by safely directing the food, saliva, and secretions accumulated in the pharynx into the esophagus to prevent aspiration and entry into the trachea. Thus, swallowing frequency may be correlated with the incidence of pneumonia. In this study, we aimed to investigate the relationship between swallowing frequency and history of pneumonia in patients with severe cerebral palsy.
Methods
Fifty-seven patients with cerebral palsy were included in this study. Swallowing frequency was measured three times for each patient on separate days, and the reproducibility was examined by calculating the intraclass correlation coefficient. Further, the relationship between swallowing frequency and history of pneumonia was investigated using multivariate logistic regression analysis.
Results
While swallowing frequency differed between participants, it was constant within individuals (intraclass correlation coefficient: 0.941). Furthermore, the swallowing frequencies per hour were 12.2 ± 12.2 and 27.0 ± 20.4 in the patient groups with and without a history of pneumonia, respectively (
P
< 0.001). Swallowing frequency (odds ratio: 10.489, 95% confidence interval: 2.706–40.663,
P
= 0.001) was significantly associated with the incidence of pneumonia in the previous year.
Conclusions
Swallowing frequency could be used as an index for assessing the risk of dysphagia and pneumonia in patients with severe cerebral palsy.
Journal Article
Impact of tumor burden on survival in patients with recurrent or metastatic head and neck cancer treated with immune checkpoint inhibitors
2022
Immune checkpoint inhibitors (ICIs) have become the standard treatment for recurrent or metastatic head and neck cancer (RM-HNC). However, many patients fail to benefit from the treatment. Previous studies have revealed that tumor burden predicts the efficacy of ICIs, but this association remains unclear for RM-HNC. We retrospectively analyzed 94 patients with RM-HNC treated with ICI monotherapy. We estimated the tumor burden using the baseline number of metastatic lesions (BNML) and the baseline sum of the longest diameters of the target lesions (BSLD), and evaluated the association between BNML, BSLD, and standardized uptake value (SUV) and clinical outcomes. The median progression-free survival (PFS) was 7.1 and 3.1 months in the low-BNML and high-BNML groups, respectively (p = 0.010). The median PFS was 9.1 and 3.5 months in the low-BSLD and high-BSLD groups, respectively (p = 0.004). Moreover, patients with high SUVmax levels had worse overall survival (OS) and PFS. BNML, BSLD, and SUVmax are useful prognostic factors in patients with RM-HNC treated with ICIs. Imaging examinations before ICI treatment are recommended to predict the efficacy of ICIs. If the tumor burden is high, cytotoxic anticancer agents may be administered concomitantly with or prior to ICI monotherapy.
Journal Article
Giant extrachromosomal element “Inocle” potentially expands the adaptive capacity of the human oral microbiome
2025
Survival strategy of bacteria is expanded by extrachromosomal elements (ECEs). However, their genetic diversity and functional roles for adaptability are largely unknown. Here, we discover a novel family of intracellular ECEs using 56 saliva samples by developing an efficient microbial DNA extraction method coupled with long-read metagenomics assembly. Even though this ECE family was not hitherto identified, our global prevalence analysis using 476 salivary metagenomic datasets elucidates that these ECEs reside in 74% of the population. These ECEs, which we named, “Inocles”, are giant plasmid-like circular genomic elements of 395 kb in length, including
Streptococcus
as a host bacterium. Inocles encode a series of genes that contribute to intracellular stress tolerance, such as oxidative stress and DNA damage, and cell wall biosynthesis and modification involved in the interactions with oral epithelial cells. Moreover, Inocles exhibit significant positive correlations with immune cells and proteins responding to microbial infection in peripheral blood. Intriguingly, we examine and find their marked reductions among 68 patients of head and neck cancers and colorectal cancers, suggesting its potential usage for a novel biomarker of gastrointestinal cancers. Our results suggest that Inocles potentially boost the adaptive capacity of host bacteria against various stressors in the oral environment.
This study identified prevalent giant extrachromosomal elements from the human oral microbiome. The genetic and ecological analysis provides insight on the potential contribution of this element in adaptation against multiple oral environmental stressors.
Journal Article
Proper Management of the Clinical Exposure Index Based on Body Thickness Using Dose Optimization Tools in Digital Chest Radiography: A Phantom Study
2021
In radiography, the exposure index (EI), as per the International Electrotechnical Commission standard, depends on the incident beam quality and exposure dose to the digital radiography system. Today automatic exposure control (AEC) systems are commonly employed to obtain the optimal image quality. An AEC system can maintain a constant incident exposure dose on the image receptor regardless of the patient thickness. In this study, we investigated the relationship between body thickness, entrance surface dose (ESD), EI, and the exposure indicator (S value) with the aim of using EI as the dose optimization tool in digital chest radiography (posterior–anterior and lateral projection). The exposure condition from the Korean national survey for determining diagnostic reference levels and two digital radiography systems (photostimulable phosphor plate and indirect flat panel detector) were used. As a result, ESD increased as the phantom became thicker with constant exposure indicator, which indicates similar settings to an AEC system, but the EI indicated comparatively constant values without following the tendency of ESD. Therefore, body thickness should be considered under the AEC system for introducing EI as the dose optimization tool in digital chest radiography.
Journal Article
Biweekly administration of cetuximab in Japanese patients with recurrent or metastatic head and neck cancer
2022
BackgroundCetuximab (Cmab) plays an important role in the treatment for recurrent or metastatic head and neck cancer (R/M HNC). To date, however, no safety data on biweekly administration of cetuximab at a dose of 500 mg/m2 (biweekly Cmab) for Japanese HNC patients have been available.MethodsWe retrospectively reviewed the clinical records of five R/M HNC patients who received biweekly Cmab in our institute between January 2016 and September 2021 and compared the safety profile between two phases of weekly 250 mg/m2 and biweekly 500 mg/m2 Cmab in the identical patients.ResultsAll patients initially received Cmab in combination with chemotherapy. Chemotherapy consisted of paclitaxel plus carboplatin in two patients, cisplatin + 5-FU in one patient, and paclitaxel in two patients. Three patients switched treatment schedule from weekly Cmab to biweekly Cmab, while two patients received biweekly Cmab after completion of chemotherapy. The main reason for switching to biweekly Cmab was an unacceptably long commuting time to the hospital. The median duration of Cmab was 217 days (49–321) during weekly Cmab with or without chemotherapy and 42 days (28–175) during biweekly Cmab. Median dose of biweekly Cmab was 4 (3–12). During biweekly Cmab, worsened (Grade ≥ 2) toxicities were observed in two patients: one with grade 2 dry skin and the second with grade 2 skin infection. None developed grade ≥ 3 adverse events or discontinued treatment due to Cmab-related adverse events.ConclusionBiweekly Cmab was well tolerated and did not demonstrate severe toxicities related to Cmab for R/M HNC.
Journal Article