RESUMO
OBJECTIVE: To evaluate the prevalence and rate of a missed diagnosis of sacroiliitis on abdominal computed tomography (CT) in patients with inflammatory bowel disease (IBD). Factors associated with sacroiliitis were also assessed. METHOD: This retrospective study included 210 patients with IBD (mean age 31.1 years) who underwent abdominal CT. Based on a validated abdominal CT scoring tool, bilateral sacroiliac (SI) joints on abdominal CT in the whole study population were retrospectively reviewed. Subsequently, patients were classified into the 'patients with sacroiliitis' group and the 'patients without sacroiliitis' group. Univariate and multivariate regression analyses were used to clarify the factors associated with sacroiliitis. RESULTS: Sacroiliitis was identified in 26 out of 210 patients (12.4%). However, sacroiliitis was recognized on the primary reading in only five of these 26 patients (19.2%) and was missed on the initial report in the remaining 21 patients (80.8%). Among the 21 patients, 20 (95.2%) were finally diagnosed with axial spondyloarthritis (axSpA). There was a higher prevalence of female sex (p = 0.04), upper gastrointestinal involvement (p = 0.04), and back pain (p < 0.01) in patients with sacroiliitis than in those without sacroiliitis. However, on multivariate analysis, back pain was the only factor associated with sacroiliitis (p = 0.01). CONCLUSION: Physicians should carefully evaluate SI joints on abdominal CT in patients with IBD to enable early detection of sacroiliitis, potentially leading to an early diagnosis of axSpA. In addition, if patients with IBD present with back pain, the possibility of sacroiliitis should be considered.
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Doenças Inflamatórias Intestinais , Sacroileíte , Tomografia Computadorizada por Raios X , Humanos , Feminino , Masculino , Sacroileíte/diagnóstico por imagem , Sacroileíte/epidemiologia , Adulto , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Doenças Inflamatórias Intestinais/epidemiologia , Doenças Inflamatórias Intestinais/diagnóstico por imagem , Doenças Inflamatórias Intestinais/complicações , Prevalência , Pessoa de Meia-Idade , Adulto Jovem , Diagnóstico Ausente/estatística & dados numéricos , Articulação Sacroilíaca/diagnóstico por imagem , Espondiloartrite Axial/epidemiologia , Espondiloartrite Axial/diagnóstico por imagemRESUMO
Acupuncture is a potential therapy for breast cancer-related lymphedema (BCRL). Despite a recent meta-analysis on efficacy, data on acupuncture safety in BCRL are lacking. Current clinical guidelines recommend avoiding needling in the upper extremity affected by lymph node dissection. We undertook a systematic review focusing on acupuncture safety and treatment protocols in clinical trials for BCRL. Literature searches were conducted in PubMed, Ovid, CINAHL, and Cochrane library. Eight clinical trials on acupuncture for BCRL were analyzed. The Standards of Acupuncture intervention (STRICTA 2010) and Cochrane risk of bias (RoB2 2019) were applied to assess methods for acupuncture interventions within Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Quantity and severity of adverse events (AE) were reviewed. A total of 189 subjects participated in 8 clinical trials with 2965 acupuncture treatments. No serious adverse events (SAE) were reported regardless of treatment laterality or protocol, with only a single grade 2 skin infection in 2,965 total treatments (0.034%), including 1,165 bilateral and 225 ipsilateral treatments. Our comprehensive review of clinical trials of acupuncture for BCRL demonstrated no significant adverse events in 2,965 treatments, including 1,390 in the affected limb. An approach for routine integration of acupuncture into BCRL maintenance therapy is proposed.
Assuntos
Terapia por Acupuntura , Linfedema Relacionado a Câncer de Mama , Neoplasias da Mama , Linfedema , Humanos , Feminino , Neoplasias da Mama/complicações , Neoplasias da Mama/terapia , Linfedema Relacionado a Câncer de Mama/etiologia , Linfedema Relacionado a Câncer de Mama/terapia , Terapia por Acupuntura/efeitos adversos , Terapia por Acupuntura/métodos , Extremidade Superior , Linfedema/etiologia , Linfedema/terapiaRESUMO
BACKGROUND: Since publication of the original Position Paper on Olfactory Dysfunction in 2017 (PPOD-17), the personal and societal burden of olfactory disorders has come sharply into focus through the lens of the COVID-19 pandemic. Clinicians, scientists and the public are now more aware of the importance of olfaction, and the impact of its dysfunction on quality of life, nutrition, social relationships and mental health. Accordingly, new basic, translational and clinical research has resulted in significant progress since the PPOD-17. In this updated document, we present and discuss currently available evidence for the diagnosis and management of olfactory dysfunction. Major updates to the current version include, amongst others: new recommendations on olfactory related terminology; new imaging recommendations; new sections on qualitative OD and COVID-19 OD; updated management section. Recommendations were agreed by all co-authors using a modified Delphi process. CONCLUSIONS: We have provided an overview of current evidence and expert-agreed recommendations for the definition, investigation, and management of OD. As for our original Position Paper, we hope that this updated document will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency, and generalisability of work in this field.
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COVID-19 , Transtornos do Olfato , Humanos , Olfato , Qualidade de Vida , Pandemias , Transtornos do Olfato/diagnóstico , Transtornos do Olfato/terapia , Transtornos do Olfato/epidemiologiaRESUMO
Intraoperative femoral fracture is a common complication during cementless total hip arthroplasty (THA). Cerclage wiring has been used for this type of fractures to attain intraoperative stability of the femoral stem. We designed a new technique to treat Mallory type 1 intraoperative femoral fractures. We excised fractured femoral neck fragment and without additional fixation and lightly tapped down the femoral stem to obtain a tight contact to the femoral cortex at the subtrochanteric level. In this case series, we described this technique and reported its outcomes. From January 2015 to December 2017, 600 cementless THAs (557 patients) were done with use of a proximally coated tapered stem design at our department. Among the 600 THAs, Mallory type 1 intraoperative femoral fracture occurred in 8 hips (8 patients), and all of them were treated with the excision of the fractured femoral neck. Mean age of the 8 patients was 58.1 years (range, 30.4 to 81.3 years) at the time of surgery. We report the results of this new technique at postoperative 2 to 5 years (mean, 3.4 years). All stems were placed in the neutral position. There was no revision and no stem showed any evidence of subsidence or loosening during the follow-up. The mean Harris hip score was 85.9 points at the latest follow-up. We recommend to use the femoral neck excision technique for the treatment of Mallory type 1 intraoperative femoral fractures.
Assuntos
Artroplastia de Quadril , Fraturas do Fêmur , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Colo do Fêmur , Artroplastia de Quadril/efeitos adversos , Fêmur , Fixação Interna de FraturasRESUMO
OBJECTIVE: Mycoplasma pneumoniae (M. pneumoniae) pneumonia is the second-most common cause of community-acquired pneumonia (CAP). This study aimed at investigating into the prevalence of macrolide-resistant M. pneumoniae (MRMP) with respiratory virus co-infection and the antibiotic prescriptions in children with CAP in four provinces in Korea, and to assess the variations in the findings across regions and throughout the year. PATIENTS AND METHODS: This prospective study was conducted in 29 hospitals in Korea between July 2018 and June 2020. Among the enrolled 1,063 children with CAP, all 451 patients with M. pneumoniae underwent PCR assays of M. pneumoniae and respiratory viruses, and the presence of point mutations of residues 2063 and 2064 was evaluated. RESULTS: Gwangju-Honam (88.6%) showed the highest prevalence of MRMP pneumonia, while Daejeon-Chungcheong (71.3%) showed the lowest, although the differences in prevalence were not significant (p=0.074). Co-infection of M. pneumoniae pneumonia and respiratory virus was observed in 206 patients (45.4%), and rhinovirus co-infection (101 children; 22.2%) was the most frequent. The prevalence of MRMP pneumonia with respiratory virus co-infection and the antibiotic prescriptions differed significantly among the four provinces (p < 0.05). The monthly rate of MRMP pneumonia cases among all cases of M. pneumoniae pneumonia and tetracycline or quinolone prescriptions did not differ significantly among the four regions (trend p > 0.05) during the study period. CONCLUSIONS: The prevalence of M. pneumoniae pneumonia with virus co-infection and antibiotic prescriptions could differ according to region, although the MRMP pneumonia rate showed no difference within Korea.
Assuntos
Coinfecção , Infecções Comunitárias Adquiridas , Pneumonia por Mycoplasma , Viroses , Vírus , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Criança , Coinfecção/complicações , Coinfecção/tratamento farmacológico , Coinfecção/epidemiologia , Farmacorresistência Bacteriana , Humanos , Macrolídeos/uso terapêutico , Mycoplasma pneumoniae/genética , Pneumonia por Mycoplasma/tratamento farmacológico , Pneumonia por Mycoplasma/epidemiologia , Prescrições , Estudos Prospectivos , Viroses/tratamento farmacológicoRESUMO
PURPOSE: Chronic endometritis (CE) is diagnosed via endometrial biopsy and staining for plasma cells. A threshold plasma cell count that identifies CE and predicts pregnancy outcomes has not been established, and the prevalence of plasma cells in the general infertile population is unknown. The purpose of this study was to determine the prevalence of plasma cells in the general infertile population and whether a threshold exists which predicts live birth. METHODS: Endometrial samples were obtained prospectively from 80 women undergoing IVF, embedded in paraffin, and stained for plasma cells using mouse mono-clonal antibody for CD138. Slides were reviewed at 20× magnification and 10 random images captured. Three reviewers graded each image for plasma cells. Participants underwent single, euploid, and frozen blastocyst transfer. RESULTS: Forty-nine percent of samples had ≥1 plasma cell across 10 HPFs, 11% had ≥5 cells across 10 HPFs, and 4% had ≥10 cells across 10 HPFs. There was no difference in prevalence between those who did and did not achieve live birth. Using thresholds of 1, 5, and 10 plasma cells per 10 HPFs, there were no differences in implantation, clinical pregnancy, clinical pregnancy loss, or live birth rates between patients with and without CE. CONCLUSION: Endometrial plasma cells are present in half the general infertile population and do not predict implantation, clinical pregnancy, clinical pregnancy loss, or live birth rates at low levels.
Assuntos
Endometrite , Nascido Vivo , Animais , Endometrite/diagnóstico , Endométrio/patologia , Feminino , Fertilização in vitro , Humanos , Nascido Vivo/epidemiologia , Camundongos , Gravidez , Taxa de Gravidez , Estudos Retrospectivos , Coloração e RotulagemRESUMO
Study objective: This study sought to evaluate the associations between social determinants of health (SDOH) at the time of first pregnancy and subsequent cardiometabolic health, defined as the development of metabolic syndrome. Design: nuMoM2b-HHS (Nulliparous Pregnancy Outcomes Study- Monitoring Mothers-to-Be-Heart Health Study) is an ongoing prospective cohort study. Setting: Eight academic medical centers enrolled and continue to follow participants. Participants: 4484 participants followed a mean of 3.2 years from the time of their first pregnancy. Interventions: N/a. Main outcome measure: Unadjusted and adjusted Poisson regression models with robust standard errors were used to obtain relative risks and 95% confidence intervals estimating the risk of metabolic syndrome for each baseline SDOH. In secondary analyses we examined the associations between SDOH and incident hypertension, obesity, and diabetes mellitus. Results: Metabolic syndrome developed in 13.6% of participants. Higher socioeconomic position at the time of pregnancy was associated with lower rates of metabolic syndrome [income > 200% poverty level aRR 0.55 (95% CI, 0.42-0.71), attainment of a bachelor's degree aRR 0.62 (0.46-0.84) or higher aRR 0.50 (0.35-0.71)], while being single [aRR 1.45 (95% CI, 1.18-1.77)] and having low health literacy were associated with a greater risk of metabolic syndrome [aRR 1.98 (95% CI, 1.28-3.07)]. Conclusions: Over a short interval following first pregnancy, participants accumulated high proportions of cardiovascular risk factors and metabolic syndrome, with some risk associated with SDOH. The impact of interventions addressing SDOH in pregnant people on cardiometabolic health should be tested as a means of reducing health inequities at the population level.
Assuntos
Ácidos Nucleicos , Escabiose , Animais , Humanos , Sarcoptes scabiei , Escabiose/diagnósticoAssuntos
COVID-19 , Dermatopatias Infecciosas , Surtos de Doenças , Humanos , Incidência , SARS-CoV-2RESUMO
The gut microbiota communicates with the brain through microbiota-gut-brain (MGB) and hypothalamus-pituitary-adrenal (HPA) axes and other pathways. Excessive expression of interleukin (IL)-6 is closely associated with the occurrence of the psychiatric disorders depression and dementia. Therefore, to understand whether IL-6 expression-suppressing probiotics could alleviate psychiatric disorders, we isolated IL-6 expression-inhibiting Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) NK112 from the human faecal bacteria strain collection (Neurobiota Research Center, Seoul, Korea) and examined its therapeutic effect for the depression and cognitive impairment in mice. C57 BL/6J mice with depression and cognitive impairment were prepared by exposure to Escherichia coli K1. Oral gavage of NK112 significantly alleviated K1-induced anxious, depressive, and memory-impaired behaviours in the elevated plus maze, tail-suspension and Y-maze tasks, IL-1ß, IL-6, and tumour necrosis factor (TNF)-α expression, and nuclear factor kappa beta (NF-κB) activation in the hippocampus, while K1-suppressed brain-derived neurotrophic factor (BDNF) expression increased. Treatment with NK112 also improved K1-induced myeloperoxidase activity, IL-6 and TNF-α expression, and NF-κB activation in the colon and reduced K1-induced Proteobacteria population in the gut microbiota. Heat-killed NK112 and its lysate supernatant, and precipitate fractions also improved anxiety/depression, cognitive impairment, and colitis in mice. In conclusion, NK112, even if heat-killed or lysed, alleviated K1 stress-induced colitis, anxiety/depression, and cognitive impairment by suppressing IL-6, TNF-α, and BDNF expression through the regulation of gut microbiota and NF-κB activation.
Assuntos
Disfunção Cognitiva , Depressão , Escherichia coli/patogenicidade , Microbioma Gastrointestinal , Lacticaseibacillus paracasei , Probióticos/uso terapêutico , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Disfunção Cognitiva/terapia , Colite/terapia , Depressão/terapia , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND: Angiotensin-converting enzyme 2 (ACE2), a receptor targeted by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is highly expressed in the nasal mucosa. Chronic rhinosinusitis (CRS) shows diverse endotypes and is aggravated by viral infection. Whether viral stimulation and CRS endotype influence ACE2 expression remains unclear. We investigated the expression of ACE2 and the transmembrane protease, serine 2 (TMPRSS2), which mediate the entry of SARS-CoV-2 into cells, and assessed polyinosinic:polycytidylic acid (poly[I:C])-induced changes based on CRS endotype. METHODOLOGY: ACE2 and TMPRSS2 expression was evaluated based on CRS phenotype, endotype, and tissue type. Correlations between ACE2/TMPRSS2 expression and inflammatory mediators in nasal polyps (NP) were examined. Air-liquid interface culture experiments were performed to assess the effects of major cytokines or poly(I:C) stimulation on ACE2/TMPRSS2 expression in primary epithelial cells from healthy nasal mucosa, eosinophilic NP (ENP), and non-eosinophilic NP (NENP). RESULTS: In primary nasal epithelial cells, interleukin (IL)-13 decreased ACE2 expression but increased TMPRSS2. Eosinophilic CRS showed lower ACE2 expression than non-eosinophilic CRS, regardless of CRS phenotype. CRS endotype was an independent factor associated with ACE2/TMPRSS2 expression in NP. Serum and tissue eosinophilic marker levels were inversely correlated with ACE2 expression, whereas tissue neutrophilic marker levels and ACE2 expression were positively correlated in NP. ACE2 expression was suppressed in ENP tissues; however, a combination of poly(I:C) and IL-13 induced ACE2/TMPRSS2 upregulation in ENP. CONCLUSIONS: ENP tissues have lower ACE2 expression than NENP; however, viral stimulation promotes ACE2/TMPRSS2 upregulation in ENP.
Assuntos
COVID-19 , Sinusite , Enzima de Conversão de Angiotensina 2 , Humanos , Peptidil Dipeptidase A , SARS-CoV-2RESUMO
AIM: To develop and validate a radiomics-based model for predicting response to neoadjuvant chemotherapy (NAC) using baseline computed tomography (CT) images in patients with muscle-invasive bladder cancer (MIBC). MATERIALS AND METHODS: A radiomics signature for predicting pathological complete response (pCR) was developed using radiomics features selected by a random forest classifier on baseline CT images, and imaging predictors were identified in the training set (87 patients). By incorporating imaging predictors and radiomics signature, an imaging-based model was constructed using multivariate logistic regression analysis and validated in an independent validation set consisting of 48 patients with CT from outside institutions. The performance and clinical usefulness of the imaging-based model for predicting pCR were evaluated using area under the receiver operating characteristic curve (AUC) and decision curve analysis. Using a cut-off determined in the training set, the positive likelihood ratios of the imaging-based model were calculated and compared with imaging and histological predictors. RESULTS: The radiomics signature was developed based on six stable radiomics features. An imaging-based model incorporating radiomics signature, tumour shape, tumour size, and clinical stage showed good performance for predicting pCR in both the training (AUC, 0.85; 95% confidence interval [CI], 0.78-0.93) and validation (AUC, 0.75; 95% CI, 0.60-0.86) sets, providing a larger net benefit in decision curve analysis. The imaging-based model showed a higher positive likelihood ratio (1.91) for pCR than imaging and histological predictors (1.33-1.63). CONCLUSIONS: The radiomics-based model using baseline CT images may predict the response of patients with MIBC to NAC.
Assuntos
Terapia Neoadjuvante/métodos , Tomografia Computadorizada por Raios X/métodos , Neoplasias da Bexiga Urinária/tratamento farmacológico , Neoplasias da Bexiga Urinária/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/patologia , Invasividade Neoplásica , Valor Preditivo dos Testes , Estudos Retrospectivos , Resultado do Tratamento , Bexiga Urinária/diagnóstico por imagem , Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/diagnóstico por imagemAssuntos
COVID-19/transmissão , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Tempo para o Tratamento , Traqueostomia , Adulto , Idoso , Idoso de 80 Anos ou mais , Cuidados Críticos , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias , República da Coreia/epidemiologia , SARS-CoV-2 , Traqueostomia/efeitos adversos , Traqueostomia/métodos , Resultado do TratamentoRESUMO
BACKGROUND: Neutrophils present as major inflammatory cells in refractory chronic rhinosinusitis with nasal polyps (CRSwNP), regardless of the endotype. However, their role in the pathophysiology of CRSwNP remains poorly understood. We investigated factors predicting the surgical outcomes of CRSwNP patients with focus on neutrophilic localization. METHODS: We employed machine-learning methods such as the decision tree and random forest models to predict the surgical outcomes of CRSwNP. Immunofluorescence analysis was conducted to detect human neutrophil elastase (HNE), Bcl-2, and Ki-67 in NP tissues. We counted the immunofluorescence-positive cells and divided them into three groups based on the infiltrated area, namely, epithelial, subepithelial, and perivascular groups. RESULTS: On machine learning, the decision tree algorithm demonstrated that the number of subepithelial HNE-positive cells, Lund-Mackay (LM) scores, and endotype (eosinophilic or non-eosinophilic) were the most important predictors of surgical outcomes in CRSwNP patients. Additionally, the random forest algorithm showed that, after ranking the mean decrease in the Gini index or the accuracy of each factor, the top three ranking factors associated with surgical outcomes were the LM score, age, and number of subepithelial HNE-positive cells. In terms of cellular proliferation, immunofluorescence analysis revealed that Ki-67/HNE-double positive and Bcl-2/HNE-double positive cells were significantly increased in the subepithelial area in refractory CRSwNP. CONCLUSION: Our machine-learning approach and immunofluorescence analysis demonstrated that subepithelial neutrophils in NP tissues had a high expression of Ki-67 and could serve as a cellular biomarker for predicting surgical outcomes in CRSwNP patients.
Assuntos
Pólipos Nasais , Rinite , Doença Crônica , Humanos , Pólipos Nasais/complicações , Pólipos Nasais/cirurgia , Infiltração de Neutrófilos , Neutrófilos , Rinite/complicações , Rinite/cirurgia , Resultado do TratamentoRESUMO
PURPOSE: This study investigated the degree of tumor cell infiltration in the tumor cavity and ventricle wall based on fluorescent signals of 5-aminolevulinic acid (5-ALA) after removal of the magnetic resonance (MR)-enhancing area and analyzed its prognostic significance in glioblastoma. METHODS: Twenty-five newly developed isocitrate dehydrogenase (IDH)-wildtype glioblastomas with complete resection both of MR-enhancing lesions and strong purple fluorescence on resection cavity were retrospectively analyzed. The fluorescent signals of 5-ALA were divided into strong purple, vague pink, and blue colors. The pathologic findings were classified into massively infiltrating tumor cells, infiltrating tumor cells, suspicious single-cell infiltration, and normal-appearing cells. The pathological findings were analyzed according to the fluorescent signals in the resection cavity and ventricle wall. RESULTS: There was no correlation between fluorescent signals and infiltrating tumor cells in the resection cavity (p = 0.199) and ventricle wall (p = 0.704) after resection of the MR-enhancing lesion. The median progression-free survival (PFS) and median overall survival (OS) were 12.5 (± 2.1) and 21.1 (± 3.5) months, respectively. In univariate analysis, the presence of definitive infiltrating tumor cells in the resection cavity and ventricle wall was significantly related to the PFS (p = 0.002) and OS (p = 0.027). In multivariate analysis, the absence of definitive infiltrating tumor cells improved PFS (hazard ratio: 0.184; 95% CI: 0.049-0.690, p = 0.012) and OS (hazard ratio: 0.124; 95% CI: 0.015-0.998, p = 0.050). CONCLUSIONS: After resection both of the MR-enhancing lesions and strong purple fluorescence on resection cavity, there was no correlation between remnant fluorescent signals and infiltrating tumor cells. The remnant definitive infiltrating tumor cells in the resection cavity and ventricle wall significantly influenced the prognosis of patients with glioblastoma. Aggressive surgical removal of infiltrating tumor cells may improve their prognosis.
Assuntos
Ácido Aminolevulínico/metabolismo , Neoplasias Encefálicas/patologia , Movimento Celular , Glioblastoma/patologia , Isocitrato Desidrogenase , Fármacos Fotossensibilizantes/metabolismo , Idoso , Ácido Aminolevulínico/administração & dosagem , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/cirurgia , Ventrículos Cerebrais/metabolismo , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Feminino , Fluorescência , Glioblastoma/metabolismo , Glioblastoma/mortalidade , Glioblastoma/cirurgia , Humanos , Estimativa de Kaplan-Meier , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fármacos Fotossensibilizantes/administração & dosagem , Prognóstico , Intervalo Livre de Progressão , Protoporfirinas/metabolismo , Estudos Retrospectivos , Proteínas Supressoras de Tumor/genéticaRESUMO
BACKGROUND: Deoxyxylulose 5-phosphate synthase (DXS) and deoxyxylulose 5-phosphate reductoisomerase (DXR) are the enzymes that catalyze the first two enzyme steps of the methylerythritol 4-phosphate (MEP) pathway to supply the isoprene building-blocks of carotenoids. Plant DXR and DXS enzymes have been reported to function differently depending on the plant species. In this study, the differential roles of rice DXS and DXR genes in carotenoid metabolism were investigated. RESULTS: The accumulation of carotenoids in rice seeds co-expressing OsDXS2 and stPAC was largely enhanced by 3.4-fold relative to the stPAC seeds and 315.3-fold relative to non-transgenic (NT) seeds, while the overexpression of each OsDXS2 or OsDXR caused no positive effect on the accumulation of either carotenoids or chlorophylls in leaves and seeds, suggesting that OsDXS2 functions as a rate-limiting enzyme supplying IPP/DMAPPs to seed carotenoid metabolism, but OsDXR doesn't in either leaves or seeds. The expressions of OsDXS1, OsPSY1, OsPSY2, and OsBCH2 genes were upregulated regardless of the reductions of chlorophylls and carotenoids in leaves; however, there was no significant change in the expression of most carotenogenic genes, even though there was a 315.3-fold increase in the amount of carotenoid in rice seeds. These non-proportional expression patterns in leaves and seeds suggest that those metabolic changes of carotenoids were associated with overexpression of the OsDXS2, OsDXR and stPAC transgenes, and the capacities of the intermediate biosynthetic enzymes might be much more important for those metabolic alterations than the transcript levels of intermediate biosynthetic genes are. Taken together, we propose a 'Three Faucets and Cisterns Model' about the relationship among the rate-limiting enzymes OsDXSs, OsPSYs, and OsBCHs as a "Faucet", the biosynthetic capacity of intermediate metabolites as a "Cistern", and the carotenoid accumulations as the content of "Cistern". CONCLUSION: Our study suggests that OsDXS2 plays an important role as a rate-limiting enzyme supplying IPP/DMAPPs to the seed-carotenoid accumulation, and rice seed carotenoid metabolism could be largely enhanced without any significant transcriptional alteration of carotenogenic genes. Finally, the "Three Faucets and Cisterns model" presents the extenuating circumstance to elucidate rice seed carotenoid metabolism.
Assuntos
Aldose-Cetose Isomerases/fisiologia , Carotenoides/metabolismo , Eritritol/análogos & derivados , Oryza/enzimologia , Fosfatos Açúcares/fisiologia , Aldose-Cetose Isomerases/genética , Butadienos/síntese química , Butadienos/metabolismo , Eritritol/genética , Eritritol/fisiologia , Hemiterpenos/síntese química , Hemiterpenos/metabolismo , Folhas de Planta/enzimologia , Sementes/enzimologia , Fosfatos Açúcares/genética , Transferases/genética , Transferases/fisiologiaRESUMO
Here, we report the synthesis and magnetic properties of a novel, centrosymmetric, quasi-1D spin chain system La3VWS3O6, with hexagonal crystal structure (P63/m, a = 9.460 76(3), c = 5.518 09(2) Å). Pure powders were obtained by solid-state reactions from La2O3, WO3 and metal powders of V and W. X-ray powder diffraction, specific heat, magnetization, 139La-nuclear magnetic resonance (NMR), and electric resistivity measurements indicate that the compound is a low dimensional magnet with an S = 1 spin chain that exhibits no sign of magnetic ordering above 2 K. A single ion anisotropy (D/k B ~ 10 K), caused by magneto-crystalline effects, is probably responsible for a thermodynamic entropy release at lower temperatures, which concurs with 139La-NMR data. By detailed comparison with non-centrosymmetric Ba3V2S4O3, having a very similar magnetic lattice, it is obvious that the presence of crystallographic inversion symmetry has an effect on the behaviour of the magnetic chains.
RESUMO
Resonant inelastic X-ray scattering (RIXS) is increasingly playing a significant role in studying highly correlated systems, especially since it was proven capable of measuring low-energy magnetic excitations. However, despite high expectations for experimental evidence of novel magnetic phases at high pressure, unequivocal low-energy spectral signatures remain obscured by extrinsic scattering from material surrounding the sample in a diamond anvil cell (DAC): pressure media, Be gasket and the diamond anvils themselves. A scattered X-ray collimation based medium-energy resolution (â¼100â meV) analyzer system for a RIXS spectrometer at the Ir L3-absorption edge has been designed and built to remediate these difficulties. Due to the confocal nature of the analyzer system, the majority of extrinsic scattering is rejected, yielding a clean low-energy excitation spectrum of an iridate Sr2IrO4 sample in a DAC cell. Furthermore, the energy resolution of different configurations of the collimating and analyzing optics are discussed.