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NLR family proteins act as intracellular receptors. Gene duplication amplifies the number of NLR genes, and subsequent mutations occasionally provide modifications to the second gene that benefits immunity. However, evolutionary processes after gene duplication and functional relationships between duplicated NLRs remain largely unclear. Here, we report that the rice NLR protein Pit1 is associated with its paralogue Pit2. The two are required for the resistance to rice blast fungus but have different functions: Pit1 induces cell death, while Pit2 competitively suppresses Pit1-mediated cell death. During evolution, the suppression of Pit1 by Pit2 was probably generated through positive selection on two fate-determining residues in the NB-ARC domain of Pit2, which account for functional differences between Pit1 and Pit2. Consequently, Pit2 lost its plasma membrane localization but acquired a new function to interfere with Pit1 in the cytosol. These findings illuminate the evolutionary trajectory of tandemly duplicated NLR genes after gene duplication.
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Duplicação Gênica , Proteínas NLR , Oryza , Proteínas de Plantas , Proteínas NLR/genética , Proteínas NLR/metabolismo , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Evolução Molecular , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Resistência à Doença/genética , Morte Celular , Filogenia , Regulação da Expressão Gênica de PlantasRESUMO
Small signalling peptides play important roles in various plant processes, but information regarding their involvement in plant immunity is limited. We previously identified a novel small secreted protein in rice, called immune response peptide 1 (IRP1). Here, we studied the function of IRP1 in rice immunity. Rice plants overexpressing IRP1 enhanced resistance to the virulent rice blast fungus. Application of synthetic IRP1 to rice suspension cells triggered the expression of IRP1 itself and the defence gene phenylalanine ammonia-lyase 1 (PAL1). RNA-seq results revealed that 84% of genes up-regulated by IRP1, including 13 OsWRKY transcription factors, were also induced by a microbe-associated molecular pattern (MAMP), chitin, indicating that IRP1 and chitin share a similar signalling pathway. Co-treatment with chitin and IRP1 elevated the expression level of PAL1 and OsWRKYs in an additive manner. The increased chitin concentration arrested the induction of IRP1 and PAL1 expression by IRP1, but did not affect IRP1-triggered mitogen-activated protein kinases (MAPKs) activation. Collectively, our findings indicate that IRP1 functions as a phytocytokine in rice immunity regulating MAPKs and OsWRKYs that can amplify chitin and other signalling pathways, and provide new insights into how MAMPs and phytocytokines cooperatively regulate rice immunity.
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Oryza , Proteínas de Plantas , Proteínas de Plantas/metabolismo , Imunidade Vegetal/fisiologia , Transdução de Sinais/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Peptídeos/metabolismo , Quitina/metabolismo , Oryza/metabolismo , Doenças das Plantas/microbiologia , Regulação da Expressão Gênica de PlantasRESUMO
Global DNA methylation levels in peripheral blood leukocytes can be a biomarker for cancer risk; however, levels can be changed by various factors such as environmental pollutants. We investigated the association between serum concentrations of perfluoroalkyl substances (PFASs) and global DNA methylation levels of leukocytes in a cross-sectional study using the control group of a Japanese breast cancer case-control study [397 women with a mean age of 54.1 (SD 10.1) years]. Importantly, our analysis distinguished branched PFAS isomers as different from linear isomers. The serum concentrations of 20 PFASs were measured by in-port arylation gas-chromatography negative chemical ionization mass spectrometry. Global DNA methylation levels in peripheral blood leukocytes were measured using a luminometric methylation assay. Associations between log10-transformed serum PFAS concentrations and global DNA methylation levels were evaluated by regression coefficients in multivariable robust linear regression analyses. Serum concentrations of 13 PFASs were significantly associated with increased global DNA methylation levels in leukocytes. Global DNA methylation was significantly increased by 1.45 %-3.96 % per log10-unit increase of serum PFAS concentration. Our results indicate that exposure to PFASs may increase global DNA methylation levels in peripheral blood leukocytes of Japanese women.
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Ácidos Alcanossulfônicos , Poluentes Ambientais , Fluorocarbonos , Humanos , Feminino , Pessoa de Meia-Idade , Estudos Transversais , Metilação de DNA , Estudos de Casos e Controles , População do Leste Asiático , Cromatografia Gasosa-Espectrometria de MassasRESUMO
Postoperative chylothorax occurs relatively rarely after pulmonary resections, often caused intraoperatively by injury to the thoracic duct. We describe a case of postoperative chylothorax after lung cancer surgery with an aberrant thoracic duct course. A 66-year-old man showed abnormal findings on chest computed tomography (CT) during health screening and was suspected with primary lung cancer. Then, he underwent a right upper lobectomy with mediastinal lymph-node dissection. The histopathological findings confirmed lung adenocarcinoma. However, the patient developed a postoperative chylothorax and underwent revision surgery. An abnormally running thoracic duct, which was expected to flow into the right venous angle, was found at the cranial side of the right superior mediastinal dissection area and was clipped. Considering the many variations in the route of the thoracic duct, thoracic surgeons should remain alert for postoperative chylothorax when performing lung cancer surgery with mediastinal lymph-node dissection and prepare treatment strategies accordingly.
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BACKGROUND: : Fitting a femoral prosthesis in a transfemoral amputee with a very short amputation stump is challenging. This case report aimed to introduce an effective and simple method that can preserve the residual limb length by the implantation of antibiotic-loaded bone cement for the treatment of a patient with femoral periprosthetic infection. CASE: : A 30-year-old man who had osteosarcoma at the age of 13 years underwent transfemoral amputation 17 years after the initial surgery because of periprosthetic infection. Antibiotic-loaded bone cement was inserted into the infected bone marrow to control the residual infection and to preserve the stump length. The infection resolved, and the patient regained functional gait using a femoral prosthesis. DISCUSSION: : This case report demonstrates the usefulness of antibiotic-loaded cement in preserving the length of residual limbs and for femoral prosthesis fitting after periprosthetic infection. Maintaining the residual bone length is crucial in amputees for the functional fitting of femoral prostheses. The use of antibiotic-loaded bone cement has potential as a simple and useful surgical option in amputees after periprosthetic infection.
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BACKGROUND: Perfluoroalkyl substances (PFASs) may contribute to causing breast cancer; however, associations between exposure to PFASs and risk of breast cancer are controversial. OBJECTIVES: In the present study, we newly distinguished branched isomers of PFASs from their linear isomers and aimed to investigate the association between serum PFAS concentrations and breast cancer risk in Japanese women. METHODS: We used a case-control design to study 405 eligible matched pairs attending four hospitals in Nagano Prefecture, Japan from May 2001 to September 2005. We used in-port arylation gas-chromatography mass spectrometry with negative chemical ionization to measure serum concentrations of 20 PFAS congeners. We calculated multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer and its hormone-receptor subtypes by quartiles or tertiles of serum PFASs. RESULTS: After multivariable adjustment for breast cancer risk factors, we found that serum concentrations of 20 PFAS congeners were significantly inversely associated with risk of breast cancer. Comparing the extreme quartiles of linear isomers of perfluorooctane sulfonate or perfluorooctanoic acid, ORs were 0.15 (95% CI: 0.07, 0.33 P for trend <0.0001) and 0.21 95% CI: 0.10, 0.44 P for trend <0.0001). Among postmenopausal women, whereas we found the linear isomer of perfluorotridecanoic acid to be inversely associated with breast cancer risk, a medium degree of exposure to the branched isomer of perfluorotridecanoic acid was associated with a marginally increased risk of breast cancer (OR [95% CI] = 1.74 [0.98, 3.09]). DISCUSSION: In our case-control study, we found overall no association between serum PFAS concentrations and increased risk of breast cancer. Many inverse associations between serum PFAS concentrations and breast cancer risk were found.
Assuntos
Ácidos Alcanossulfônicos , Neoplasias da Mama , Poluentes Ambientais , Fluorocarbonos , Neoplasias da Mama/induzido quimicamente , Neoplasias da Mama/epidemiologia , Estudos de Casos e Controles , Feminino , Humanos , Japão/epidemiologiaRESUMO
BACKGROUND: Recent studies have suggested that erythropoiesis-stimulating agents (ESAs) may accelerate not only angiogenesis but also vasculogenesis, beyond erythropoiesis. METHODS: We conducted a 12-week prospective study in 51 dialysis patients; 13 were treated with recombinant human erythropoietin (EPO, 5290.4 ± 586.9 IU/week), 16 with darbepoetin (DA, 42.9 ± 4.3 µg/week), 12 with epoetin ß pegol (CERA, 40.5 ± 4.1 µg/week) and 10 with no ESAs. Vascular mediators comprising endothelial progenitor cells (EPCs), vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), and high-sensitivity C-reactive protein (hs-CRP) were measured at 0 and 12 weeks. EPCs were measured by flow cytometry as CD45lowCD34+CD133+ cells. RESULTS: The EPC count increased significantly to a greater extent in the EPO group than in the other three group, and increased significantly from 0 to 12 weeks in a EPO dose-dependent manner. In both the DA and CERA groups, the EPC count did not change at 12 weeks. Serum levels of VEGF, MMP-2 and hs-CRP were not affected by ESA treatment in all groups. In the CERA group, serum ferritin decreased significantly compared to the no-ESA group and correlated with CERA dose, although use of iron was permitted if required during the prospective study period of 12 weeks. CONCLUSIONS: When patients on dialysis were treated with clinical doses of various ESAs, only EPO induced a significant increase of circulating EPCs from bone marrow, whereas, DA and CERA had no effect.
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Anemia/tratamento farmacológico , Células Progenitoras Endoteliais/efeitos dos fármacos , Eritropoetina/farmacologia , Hematínicos/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Idoso , Anemia/sangue , Anemia/etiologia , Proteína C-Reativa/metabolismo , Contagem de Células , Darbepoetina alfa/farmacologia , Eritropoetina/uso terapêutico , Feminino , Ferritinas/sangue , Humanos , Falência Renal Crônica/complicações , Falência Renal Crônica/terapia , Masculino , Metaloproteinase 2 da Matriz/sangue , Pessoa de Meia-Idade , Polietilenoglicóis/farmacologia , Estudos Prospectivos , Proteínas Recombinantes/farmacologia , Diálise Renal , Fator A de Crescimento do Endotélio Vascular/sangueRESUMO
BACKGROUND: As Asians are more vulnerable to febrile neutropenia (FN) than Caucasians, evaluations of FN incidence and risk factors in Asians are important for the appropriate use of primary pegfilgrastim (PEG-G). PATIENTS AND METHODS: Japanese breast cancer patients receiving standard adjuvant chemotherapies were prospectively enrolled in multicenter institutions from August 2015 to July 2017. FN was evaluated from 2 treatment policies: true FN (T-FN): ≥37.5 °C, grade 4 neutropenia, mandatory hospital visit (visiting); surrogate FN (S-FN): ≥37.5 °C, oral antibiotic, no mandatory visit (non-visiting). PEG-G was used at the physicians' discretion. The primary endpoint was FN incidence during all cycles. Multivariate logistic regression analysis was performed to identify T-FN risk factors. RESULTS: Of 1005 enrolled patients, 980 women treated with FEC, E(A)C, and TC were analyzed. The FN incidence proportions in all patients were 22.5%, 27.5%, and 33.9% for FEC, E(A)C, and TC, respectively. Those of T-FN were 27.7%, 22.4%, and 36.6%; those of S-FN were 17.3%, 32.4%, and 31.5% with more frequent primary PEG-G usage. The relative dose intensity (RDI) of the 3 regimens was ≥0.85 in both groups. In the analysis of risk factors, TC (odds ratio = 2.67), age ≥ 65 years (2.24), and pretreatment absolute neutrophil count (ANC)/1000 µl (0.8) remained significant. CONCLUSIONS: FN incidences were above 20% in the 3 regimens, with TC showing the highest. RDI was maintained at a high level in both visiting and non-visiting groups. Patient-related risk factors were age and pretreatment ANC.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Neutropenia Febril/induzido quimicamente , Terapia Neoadjuvante/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/complicações , Neoplasias da Mama/patologia , Neutropenia Febril/epidemiologia , Feminino , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Hibridização in Situ Fluorescente , Japão , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Fatores de RiscoRESUMO
A 21-year-old man was admitted with fever and back pain. Chest computed tomography(CT) showed a cystic mass of 7×6 cm in the right middle mediastinum. After 3 days, symptoms worsen, and chest X-ray revealed the enlargement of the cyst, and an emergent operation was performed. Since the tumor was severely adhered to the superior vena cava and the azygous vein, the cystic mass was partially resected. The pathological diagnosis was bronchogenic cyst.
Assuntos
Cisto Broncogênico , Cisto Broncogênico/cirurgia , Febre , Humanos , Masculino , Mediastino , Tórax , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
KEY MESSAGE: Dart1-24, one of the 37 autonomous DNA transposon Dart1s, was heritably activated by the demethylation of the 5' region following 5-azaC treatment of rice seeds. Transposons are controlled by epigenetic regulations. To obtain newly activated autonomous elements of Dart1, a DNA transposon, in rice, seeds of a stable pale yellow leaf (pyl-stb) mutant caused by the insertion of nDart1-0, a nonautonomous element in OsClpP5, were treated with 5-azaC, a demethylating agent. In the 5-azaC-treated M1 plants, 60-70% of the plants displayed variegated pale yellow leaf (pyl-v) phenotype, depending on the concentration of 5-azaC used, suggesting that inactivated Dart1 might become highly activated by 5-azaC treatment and nDart1-0 was excised from OsClpP5 by the activated Dart1s. Although the M2 plants derived from most of these pyl-v plants showed stable pyl phenotypes, some variegated M1 plants generated pyl-v M2 progeny. These results indicated that most M1 pyl-v phenotypes at M1 were not heritable. Dart1-24, 1-27 and 1-28 were expressed in the M2 pyl-v plants, and mapping analysis confirmed that Dart1-24 was newly activated. Further, the transgenerational activation of Dart1-24 was demonstrated to be caused by the demethylation of nucleotides in its 5' region.
Assuntos
Azacitidina/farmacologia , Elementos de DNA Transponíveis , Oryza/genética , Mapeamento Cromossômico , DNA de Plantas/genética , Regulação da Expressão Gênica de Plantas , Oryza/efeitos dos fármacos , Fenótipo , Sementes/genéticaRESUMO
OBJECTIVE: Stereotactic body radiotherapy has emerged as an attractive alternative to conventional radiotherapy for spinal metastases. However, it has limitations, including the need for advanced techniques and specific adverse effects. The present trial aimed to validate the feasibility and safety of stereotactic body radiotherapy in Japanese patients with spinal metastases. METHODS: Patients with one or two spinal metastases received stereotactic body radiotherapy of 24 Gy in two fractions. The primary endpoint was the proportion of severe adverse effects (≥ grade 3) in patients within 6 months after spine stereotactic body radiotherapy. Adverse effects were evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4. The treatment protocol was considered feasible and tolerable if the proportion of severe adverse effects was 10% or less. RESULTS: Overall, 20 spinal segments in 20 patients who registered between March 2014 and October 2015 were included. Minor and major deviations were observed in the planning of 2 and 0 cases, respectively. The treatment completion rate was 100%. The median follow-up after registration was 24.5 (range: 1-61) months. Although four patients experienced acute grade 2 adverse effects, no grade 3 or higher adverse effects were observed within 6 months after spine stereotactic body radiotherapy. Vertebral compression fractures were observed in two patients (14 and 16 months after stereotactic body radiotherapy). The local control and pain response rates at 6 months were 100 and 83%, respectively. CONCLUSION: This study demonstrated the feasibility and safety of spine stereotactic body radiotherapy in Japanese patients with spinal metastases.
Assuntos
Radiocirurgia/efeitos adversos , Radiocirurgia/métodos , Neoplasias da Coluna Vertebral/radioterapia , Neoplasias da Coluna Vertebral/secundário , Adulto , Idoso , Estudos de Viabilidade , Feminino , Fraturas por Compressão/epidemiologia , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fraturas da Coluna Vertebral/epidemiologiaRESUMO
A 63-year-old woman underwent right lower lobectomy and mediastinal dissection for lung cancer. At 5 years and 5 months after surgery, chest computed tomography revealed multiple liver metastasis. EGFR gene mutations of L858R and T790M were detected in both the primary lung cancer lesion and the liver metastasis specimen. Gefitinib was initiated as the first-line treatment, but the tumors increased in size. Osimertinib, as second-line treatment, was remarkably effective against the liver metastatic lesions and it maintained a partial response for approximately 1 year. Thus, osimertinib was effective for liver metastasis of lung cancer with EGFR mutations of L858R and T790M.
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Acrilamidas/uso terapêutico , Compostos de Anilina/uso terapêutico , Neoplasias Hepáticas , Neoplasias Pulmonares , Carcinoma Pulmonar de Células não Pequenas , Receptores ErbB , Feminino , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Pessoa de Meia-Idade , Mutação , Inibidores de Proteínas QuinasesRESUMO
AIM: To investigate tumour motion tracking uncertainties in the CyberKnife Synchrony system with single fiducial marker in liver tumours. BACKGROUND: In the fiducial-based CyberKnife real-time tumour motion tracking system, multiple fiducial markers are generally used to enable translation and rotation corrections during tracking. However, sometimes a single fiducial marker is employed when rotation corrections are not estimated during treatment. MATERIALS AND METHODS: Data were analysed for 32 patients with liver tumours where one fiducial marker was implanted. Four-dimensional computed tomography (CT) scans were performed to determine the internal target volume (ITV). Before the first treatment fraction, the CT scans were repeated and the marker migration was determined. Log files generated by the Synchrony system were obtained after each treatment and the correlation model errors were calculated. Intra-fractional spine rotations were examined on the spine alignment images before and after each treatment. RESULTS: The mean (standard deviation) ITV margin was 4.1 (2.3) mm, which correlated weakly with the distance between the fiducial marker and the tumour. The mean migration distance of the marker was 1.5 (0.7) mm. The overall mean correlation model error was 1.03 (0.37) mm in the radial direction. The overall mean spine rotations were 0.27° (0.31), 0.25° (0.22), and 0.23° (0.26) for roll, pitch, and yaw, respectively. The treatment time was moderately associated with the correlation model errors and weakly related to spine rotation in the roll and yaw planes. CONCLUSIONS: More caution and an additional safety margins are required when tracking a single fiducial marker.
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BACKGROUND: The treatment efficacy after CyberKnife stereotactic body radiotherapy (SBRT) have not been adequately addressed. The purpose of this study was to investigate pattern of recurrence according to irradiation field after CyberKnife SBRT for early-stage non-small cell lung cancer (NSCLC). METHODS: This retrospective study included patients with peripheral cT1/2N0M0 NSCLC that was treated with SBRT using a CyberKnife between May 2013 and March 2016 at single institute and followed up by more than two imaging examinations. Both operable and inoperable patients were included. Overall survival (OS) and progression-free survival (PFS) curves were estimated using the Kaplan-Meier method with 95% confidence intervals (CI). Cumulative incidence curves of recurrence were calculated and compared using the Gray's test. RESULTS: Total 71 patients were included and analyzed in this study. The median follow-up period for surviving patients was 34 months (range, 7-64 months). The 2-year OS and PFS rate were 93% (95% CI: 83-97%) and 77% (95% CI: 65-86%), respectively. The 2-year cumulative incidence rate of infield recurrence and out-of-field recurrence were 6% (95% CI: 2-14%) and 17% (95% CI: 9-27%), respectively. Gross tumor volume (GTV) ≥9 mL and diagnosis-to-treatment interval (DTI) ≥90 days were significantly associated with infield recurrence (P<0.001 and P=0.007), and epidermal growth factor receptor (EGFR) mutation was significantly associated with out-of-field recurrence (P=0.014). CONCLUSIONS: Treatment efficacy after CyberKnife SBRT for peripheral early-stage NSCLC was identical to previous conventional linac-based SBRT reports. With short follow-up period, it was found that GTV and DTI were the significant predictive factor of infield recurrence, and EGFR mutation was the significant predictive factor of out-of-field recurrence.
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BACKGROUND/AIM: We previously showed that the use of autophagy inhibitors in combination with chemotherapy can enhance anticancer effects in sarcoma cell lines. In this study, we investigated the combined effect of the autophagy inhibitor chloroquine and the mTOR inhibitor rapamycin on MG63 osteosarcoma cells. MATERIALS AND METHODS: Effects of chloroquine and/or rapamycin on cell proliferation were assessed by WST-1 assays. Effects of chloroquine and/or rapamycin on the mTOR pathway components, autophagy, and apoptosis were investigated by western blot, flow cytometry, and fluorescence microscopy using immunocytochemical staining of LC3 and Annexin V-FITC/propidium iodide. RESULTS: Rapamycin suppressed cell growth and inhibited the mTOR pathway. Rapamycin promoted autophagy by blocking the mTOR pathway, and chloroquine enhanced apoptosis by blocking autophagy. CONCLUSION: Chloroquine enhances the effects of rapamycin in inducing apoptosis via autophagy inhibition in MG63 cells. Thus, the combined therapy of chloroquine and rapamycin may be a potent treatment for osteosarcoma.
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Apoptose/efeitos dos fármacos , Autofagia , Neoplasias Ósseas/patologia , Cloroquina/farmacologia , Osteossarcoma/patologia , Sirolimo/farmacologia , Antibióticos Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Humanos , Microscopia de Fluorescência , Serina-Treonina Quinases TOR/metabolismoRESUMO
PURPOSE: This study aimed to assess the effectiveness of multiple dose-volume specifications in minimizing interinstitutional, target-prescribed, dose variations for spine stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: Seven institutions with a total of 10 treatment apparatuses participated in this study. SBRT plans for 3 representative spinal metastases were generated using 2 different protocols (Protocols 1 and 2) for target dose. While using just 2 target dose objectives (doses delivered to 95% and maximum point dose) in Protocol 1, 3 target dose constraints (doses delivered to 95% and 50% and maximum point dose) were defined in Protocol 2 with the intent to decrease target dose variation. A dose-volume histogram analysis was performed for the evaluated planning target volume (PTVevl) and critical neural structures such as the spinal cord and cauda equina. RESULTS: Doses to the organs at risk were all maintained at the maximal tolerance in both protocols; however, the interinstitutional variation of the PTVevl dose-volume histograms was significantly decreased with Protocol 2. Furthermore, the mean PTVevl covered by the prescription dose was increased from 73.0% in Protocol 1 to 85.8% in Protocol 2. There were no differences in the mean values of the nearly maximum dose of the critical neural structures between 2 protocols. CONCLUSIONS: In spine SBRT with the emphasis on preservation of critical neural structures, the target prescribed dose should be defined by using multiple dose-volume objectives to minimize user and apparatus-dependent dose variabilities for the spinal metastases that are adjacent to the critical neural structures.
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Algoritmos , Órgãos em Risco/efeitos da radiação , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias da Coluna Vertebral/cirurgia , Seguimentos , Humanos , Prognóstico , Radiometria/métodos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Neoplasias da Coluna Vertebral/patologiaRESUMO
Sporobolus virginicus is a halophytic C4 grass found worldwide, from tropical to warm temperate regions. One Japanese genotype showed a salinity tolerance up to 1.5 M NaCl, a three-fold higher concentration than the salinity of sea water. To identify the key genes involved in the regulation of salt tolerance in S. virginicus, we produced 3500 independent transgenic Arabidopsis lines expressing random cDNA from S. virginicus and screened 10 lines which showed enhanced salt tolerance compared with the wild type in a medium containing 150 mM NaCl. Among the selected lines, two contained cDNA coding glycine-rich RNA-binding proteins (SvGRP1 and SvGRP2). This is the first reports on the function of GRPs from halophytes in salt tolerance though reports have shown GRPs are involved in diverse biological and biochemical processes including salt tolerance in Arabidopsis and some other glycophytes. Transcriptomic analysis and GO enrichment analysis of SvGRP1-expressing Arabidopsis under salt stress revealed upregulation of polyol and downregulation of glucosinolate and indole acetic acid biosynthesis/metabolic pathways. Metabolomic analysis of the SvGRP1-transformant suggested that the increase in 3-aminoppropanoic acid, citramalic acid, and isocitric acid content was associated with enhanced salt tolerance. These findings could provide novel insight into the roles of GRPs in plant salt tolerance.
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Proteínas de Plantas/fisiologia , Proteínas de Ligação a RNA/fisiologia , Tolerância ao Sal/genética , Plantas Tolerantes a Sal/genética , Sequência de Aminoácidos , Arabidopsis/genética , Perfilação da Expressão Gênica , Genótipo , Metaboloma , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/fisiologia , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Plantas Tolerantes a Sal/fisiologia , Alinhamento de SequênciaRESUMO
To utilize a transposon-tagged mutant as a breeding material in rice, an endogenous DNA transposon, nDart1-0, was introduced into Koshihikari by successive backcrossing together with aDart1-27, an active autonomous element. The founder line for nDart1-tagged lines of Koshihikari carried nDart1-0 on chromosome 9 and transposed nDart1-12s on chromosomes 1 and 8 and nDart1-3 on chromosome 11. In nDart1-tagged lines, there were the most abnormal phenotypic mutants and many aberrant chlorophyll mutants at seedling stage. At mature stage, many semi-sterile mutants were observed. Dwarf, reduced culm number and lesion mimic mutants were also found. In total, 43.2% of the lines segregated some phenotypic mutants. Thus, the nDart1-tagged lines of Koshihikari are expected to be potentially useful for screening stress-tolerant mutants under abiotic or biotic stress conditions.