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1.
Plant J ; 115(4): 1004-1020, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37162489

RESUMO

Photorespiration is an essential metabolic mechanism associated with photosynthesis; however, little is known about the photorespiratory pathway of conifer gymnosperms. Metabolite analyses of the leaves of 27 tree species showed that the mean glycerate content in conifer leaves was lower than that in angiosperm leaves. We performed experiments where [13 C]-serine was fed to detached shoots of a conifer (Cryptomeria japonica), via the transpiration stream, and compared the labeling patterns of photorespiratory metabolites with those of an angiosperm tree (Populus nigra), because glycerate is produced from serine via hydroxypyruvate in peroxisomes. In P. nigra, hydroxypyruvate, glycerate and glycine were labeled with 13 C, whereas in C. japonica, glycolate and a non-canonical photorespiratory metabolite, formate, were also labeled, suggesting that an H2 O2 -mediated non-enzymatic decarboxylation (NED) reaction occurs in C. japonica. We analyzed changes in the metabolite contents of leaves kept in the dark and leaves exposed to illuminated photorespiration-promoting conditions: a positive relationship between formate and serine levels in C. japonica implied that the active C1 -metabolism pathway synthesizes serine from formate. Leaf gas exchange analyses revealed that CO2 produced through NED was recaptured by chloroplasts. Database analysis of the peroxisomal targeting signal motifs of an H2 O2 -scavenging enzyme, catalase, derived from various species, including nine coniferous species, as well as analyses of peroxisomal fractions isolated from C. japonica and P. nigra leaves indicated that conifer peroxisomes had less catalase activity. These results suggest that NED and the subsequent C1 metabolism are involved in the photorespiratory pathway of conifer leaves, where peroxisomes have intrinsically low catalase activity.


Assuntos
Magnoliopsida , Traqueófitas , Peroxissomos/metabolismo , Traqueófitas/metabolismo , Catalase/metabolismo , Fotossíntese , Magnoliopsida/metabolismo , Folhas de Planta/metabolismo , Serina/metabolismo
2.
Int J Cancer ; 154(3): 425-433, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37728485

RESUMO

Lipolysis-stimulated lipoprotein receptor (LSR) is known as a lipoprotein receptor. LSR is expressed in various solid tumors, including epithelial ovarian, gastric, and colon cancers. High LSR expression is significantly associated with poor prognosis, but its role in cancer has not been fully elucidated. LSR belongs to the Ig protein superfamily, which is conserved in B7 family. Here, we assessed LSR as a novel immune checkpoint molecule. We developed a novel anti-LSR antibody (#27-6 mF-18) that defects antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activity. The #27-6 mF-18 cross-reacts with both human and mouse LSR. We found that LSR was expressed on 4T1 murine breast cancer cell line. The #27-6 mF-18 exhibited antitumor effects against the 4T1 syngeneic tumor model, a poor immunogenic model refractory to treatment with anti-PD-1 or anti-CTLA-4 antibodies. Compared with control antibody-treated mice, mice treated with #27-6 mF-18 showed significantly increased numbers of CD8+ T cells and a ratio of activated CD8+ T cells infiltrated in the tumor tissue. This antitumor effect was abrogated by CD8+ T-cell depletion through anti-CD8 antibody treatment, indicating that LSR negatively regulates tumor immunity by repressing CD8+ T cells. These findings show that LSR negatively regulates T-cell immune activity. LSR targeting could provide immune checkpoint inhibitors for cancer immunotherapy.


Assuntos
Linfócitos T CD8-Positivos , Receptores de Lipoproteínas , Humanos , Camundongos , Animais , Linfócitos T CD8-Positivos/metabolismo , Lipólise , Proteínas/metabolismo , Receptores de Lipoproteínas/metabolismo , Células MCF-7 , Linhagem Celular Tumoral
3.
J Plant Res ; 137(6): 1165-1175, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39327385

RESUMO

We have previously suggested that in rice (Oryza sativa L.) leaves of different ages and N nutrition statuses, photosystems II and I (PSII and PSI, respectively) are regulated depending on N partitioning to Rubisco, which can determine the magnitude of unutilized light energy. The robustness of this mechanism was tested using Rubisco-antisense transgenic rice plants, in which reduced N partitioning to Rubisco markedly increases unutilized light energy. In wild-type plants, N partitioning to Rubisco tended to be smaller in the leaves at lower positions owing to leaf senescence. In the transgenic plants, N partitioning to Rubisco was generally smaller than in the wild-type plants and was relatively constant among leaf positions. The quantum efficiency of PSII [Y(II)] and quantum yield of non-photochemical quenching [Y(NPQ)] correlated positively and negatively, respectively, with N partitioning to Rubisco irrespective of leaf position or genotype. The oxidation levels of the reaction center chlorophyll of PSI (P700) [Y(ND)] negatively correlated with N partitioning to Rubisco. However, in mature and early senescent leaves of the transgenic plants, Y(ND) was markedly lower than expected from N partitioning to Rubisco. These results suggest that in the transgenic plants, the regulation depending on N partitioning to Rubisco is robust for PSII but fails for PSI in mature and early senescing leaves. In these leaves, the magnitudes of P700 oxidation were found to be less than expected from the Y(II) and Y(NPQ) values. The mechanistic reasons and physiological implications of these phenomena are discussed.


Assuntos
Nitrogênio , Oryza , Complexo de Proteína do Fotossistema I , Complexo de Proteína do Fotossistema II , Folhas de Planta , Plantas Geneticamente Modificadas , Ribulose-Bifosfato Carboxilase , Oryza/genética , Oryza/enzimologia , Oryza/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Ribulose-Bifosfato Carboxilase/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema I/genética , Nitrogênio/metabolismo , Fotossíntese , Clorofila/metabolismo
4.
J Plant Res ; 137(2): 255-264, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38112982

RESUMO

The kinetic properties of Rubisco, a key enzyme for photosynthesis, have been examined in numerous plant species. However, this information on some plant groups, such as ferns, is scarce. This study examined Rubisco carboxylase activity and leaf Rubisco levels in seven ferns, including four Equisetum plants (E. arvense, E. hyemale, E. praealtum, and E. variegatum), considered living fossils. The turnover rates of Rubisco carboxylation (kcatc) in E. praealtum and E. hyemale were comparable to those in the C4 plants maize (Zea mays) and sorghum (Sorghum bicolor), whose kcatc values are high. Rubisco CO2 affinity, estimated from the percentage of Rubisco carboxylase activity under CO2 unsaturated conditions in kcatc in these Equisetum plants, was low and also comparable to that in maize and sorghum. In contrast, kcatc and CO2 affinities of Rubisco in other ferns, including E. arvense and E. variegatum were comparable with those in C3 plants. The N allocation to Rubisco in the ferns examined was comparable to that in the C3 plants. These results indicate that E. praealtum and E. hyemale have abundant Rubisco with high kcatc and low CO2 affinity, whereas the carboxylase activity and abundance of Rubisco in other ferns were similar to those in C3 plants. Herein, the Rubisco properties of E. praealtum and E. hyemale were discussed regarding their evolution and physiological implications.


Assuntos
Equisetum , Ribulose-Bifosfato Carboxilase , Dióxido de Carbono , Equisetum/metabolismo , Fotossíntese/fisiologia , Plantas/metabolismo , Zea mays/metabolismo
5.
Int J Mol Sci ; 25(4)2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38396664

RESUMO

The tunica muscularis of mammalian esophagi is composed of striated muscle and smooth muscle. Contraction of the esophageal striated muscle portion is mainly controlled by cholinergic neurons. On the other hand, smooth muscle contraction and relaxation are controlled not only by cholinergic components but also by non-cholinergic components in the esophagus. Adenosine triphosphate (ATP) is known to regulate smooth muscle contraction and relaxation in the gastrointestinal tract via purinergic receptors. However, the precise mechanism of purinergic regulation in the esophagus is still unclear. Therefore, the aim of the present study was to clarify the effects of ATP on the mechanical responses of the esophageal muscle in mice. An isolated segment of the mouse esophagus was placed in a Magnus's tube and longitudinal mechanical responses were recorded. Exogenous application of ATP induced contractile responses in the esophageal preparations. Tetrodotoxin, a blocker of voltage-dependent sodium channels in neurons and striated muscle, did not affect the ATP-induced contraction. The ATP-evoked contraction was blocked by pretreatment with suramin, a purinergic receptor antagonist. RT-PCR revealed the expression of mRNA of purinergic receptor genes in the mouse esophageal tissue. The findings suggest that purinergic signaling might regulate the motor activity of mouse esophageal smooth muscle.


Assuntos
Trifosfato de Adenosina , Músculo Estriado , Camundongos , Animais , Trifosfato de Adenosina/farmacologia , Contração Muscular/fisiologia , Esôfago , Músculo Estriado/fisiologia , Receptores Purinérgicos , Músculo Liso , Mamíferos
6.
Plant Cell Physiol ; 64(1): 55-63, 2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36208302

RESUMO

In mature leaves acclimated to low N levels and in senescent leaves, photosystems II and I (PSII and PSI, respectively) show typical responses to excess light energy. As CO2 assimilation is not transiently suppressed in these situations, the behavior of PSII and PSI is likely caused by endogenous biochemical changes in photosynthesis. In this study, this subject was studied in rice (Oryza sativa L.). Analysis was performed on mature and senescent leaves of control and N-deficient plants. Total leaf-N, Rubisco and chlorophyll (Chl) levels and their ratios were determined as biochemical parameters of photosynthesis. Total leaf-N, Rubisco and Chl levels decreased in the mature leaves of N-deficient plants and senescent leaves. The percentage of Rubisco-N in the total leaf-N decreased in these leaves, whereas that of Chl-N tended to remain almost constant in mature leaves but increased in senescent leaves. Changes in PSII and PSI parameters were best accounted for by the Rubisco-N percentage, strongly suggesting that the behavior of PSII and PSI is modulated depending on changes in N partitioning to Rubisco in mature leaves acclimated to low N levels and in senescent leaves. It is likely that a decrease in N partitioning to Rubisco leads to a decrease in Rubisco capacity relative to other photosynthetic capacities that inevitably generate excess light energy and that the operation of PSII and PSI is modulated in such situations.


Assuntos
Oryza , Complexo de Proteína do Fotossistema II , Complexo de Proteína do Fotossistema II/metabolismo , Oryza/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Fotossíntese/fisiologia , Clorofila , Folhas de Planta/metabolismo
7.
Plant Physiol ; 188(3): 1550-1562, 2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-34893891

RESUMO

The availability of inorganic phosphate (Pi) for ATP synthesis is thought to limit photosynthesis at elevated [CO2] when Pi regeneration via sucrose or starch synthesis is limited. We report here another mechanism for the occurrence of Pi-limited photosynthesis caused by insufficient capacity of chloroplast triose phosphate isomerase (cpTPI). In cpTPI-antisense transgenic rice (Oryza sativa) plants with 55%-86% reductions in cpTPI content, CO2 sensitivity of the rate of CO2 assimilation (A) decreased and even reversed at elevated [CO2]. The pool sizes of the Calvin-Benson cycle metabolites from pentose phosphates to 3-phosphoglycerate increased at elevated [CO2], whereas those of ATP decreased. These phenomena are similar to the typical symptoms of Pi-limited photosynthesis, suggesting sufficient capacity of cpTPI is necessary to prevent the occurrence of Pi-limited photosynthesis and that cpTPI content moderately affects photosynthetic capacity at elevated [CO2]. As there tended to be slight variations in the amounts of total leaf-N depending on the genotypes, relationships between A and the amounts of cpTPI were examined after these parameters were expressed per unit amount of total leaf-N (A/N and cpTPI/N, respectively). A/N at elevated [CO2] decreased linearly as cpTPI/N decreased before A/N sharply decreased, owing to further decreases in cpTPI/N. Within this linear range, decreases in cpTPI/N by 80% led to decreases up to 27% in A/N at elevated [CO2]. Thus, cpTPI function is crucial for photosynthesis at elevated [CO2].


Assuntos
Cloroplastos/metabolismo , Inibidores Enzimáticos/metabolismo , Oryza/genética , Oryza/metabolismo , Fosfatos/metabolismo , Fotossíntese/efeitos dos fármacos , Triose-Fosfato Isomerase/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Plantas Geneticamente Modificadas/metabolismo
8.
Oncology ; 101(11): 714-722, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37369179

RESUMO

INTRODUCTION: Systemic therapy provides clinical benefits to a subset of patients with advanced unresectable hepatocellular carcinoma (HCC). However, few biomarkers are available for predicting prognosis and treatment response in patients with advanced HCC undergoing treatment with systemic therapies. This study aimed to examine whether circulating cell-free DNA (cfDNA) containing circulating tumor DNA can act as a therapeutic response and prognostic biomarker in patients with advanced HCC. METHODS: We analyzed longitudinally collected plasma cfDNA of patients with advanced HCC who were naïve to systemic therapy, and assessed their prognostic and predictive values to determine treatment responses. RESULTS: cfDNA concentration positively correlated with entire tumor volume on computed tomography before (p = 0.0231) and at the end (p < 0.0001) of the first-line systemic therapy. The overall survival rate was higher in patients with cfDNA concentrations lower than the median cfDNA level at baseline compared to patients with higher cfDNA concentrations (hazard ratio, 0.2765; 95% confidence interval, 0.08-0.81; p = 0.0197). The ratio of cfDNA at 4 weeks to that at baseline was predictive of radiographic disease response. In patients with progressive disease, cfDNA concentration at 4 weeks increased significantly (p = 0.0245), whereas the concentration remained unchanged in patients with other disease courses (p = 0.9375). CONCLUSION: The baseline plasma cfDNA concentration can be used as a prognostic biomarker in patients with advanced HCC. cfDNA kinetics may also predict the tumor response to therapy and disease progression.

9.
Immunity ; 40(4): 530-41, 2014 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-24726878

RESUMO

Mast cells (MCs) mature locally, thus possessing tissue-dependent phenotypes for their critical roles in both protective immunity against pathogens and the development of allergy or inflammation. We previously reported that MCs highly express P2X7, a receptor for extracellular ATP, in the colon but not in the skin. The ATP-P2X7 pathway induces MC activation and consequently exacerbates the inflammation. Here, we identified the mechanisms by which P2X7 expression on MCs is reduced by fibroblasts in the skin, but not in the other tissues. The retinoic-acid-degrading enzyme Cyp26b1 is highly expressed in skin fibroblasts, and its inhibition resulted in the upregulation of P2X7 on MCs. We also noted the increased expression of P2X7 on skin MCs and consequent P2X7- and MC-dependent dermatitis (so-called retinoid dermatitis) in the presence of excessive amounts of retinoic acid. These results demonstrate a unique skin-barrier homeostatic network operating through Cyp26b1-mediated inhibition of ATP-dependent MC activation by fibroblasts.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Dermatite/imunologia , Fibroblastos/imunologia , Mastócitos/imunologia , Receptores Purinérgicos P2X7/metabolismo , Pele/metabolismo , Trifosfato de Adenosina/imunologia , Animais , Degranulação Celular/efeitos dos fármacos , Degranulação Celular/genética , Sistema Enzimático do Citocromo P-450/genética , Imidazóis/administração & dosagem , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/genética , Mastócitos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microbiota/imunologia , Receptores Purinérgicos P2X7/genética , Ácido Retinoico 4 Hidroxilase , Pele/imunologia , Pele/microbiologia , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/metabolismo , Tretinoína/imunologia
10.
J Oncol Pharm Pract ; 29(3): 619-625, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35089101

RESUMO

PURPOSE: To investigate the duration of cyclophosphamide (CPA) excretion in the sweat after administration when receiving high-dose CPA therapy as a conditioning regimen for hematopoietic stem-cell transplantation (HSCT). METHODS: Shirts and pillowcases samples (changed once a day) from 12 patients, categorized as groups 1 (n = 6), 2 (n = 4), and 3 (n = 2), receiving high-dose CPA therapy were collected, sealed, stored at 4°C, and mailed to an analytical facility for CPA estimation using LC-MS/MS. CPA was administered intravenously at a dose of 60 mg/kg on days 1, 2 (closed-system delivery for group 3), and samples were collected during days 1-4 (groups 1,3) or days 1-9 (group 2). RESULTS: CPA was detected in all 126 shirts and pillowcases. In 9 patients, excluding 1 patient who had fever during the study period and group 3 patients, the mean (range) rate of CPA excretion in sweat was 0.03% (0.01-0.12%). The mean CPA excretion in 9 patients adjusted for body weight was 19.9 µg/kg on day 1 and 0.3 µg/kg on day 4. CONCLUSIONS: This study showed that CPA was excreted for an extended duration in the patient's sweat, receiving a high-dose CPA therapy as a conditioning regimen against HSCT.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Suor , Humanos , Cromatografia Líquida , Espectrometria de Massas em Tandem , Ciclofosfamida , Condicionamento Pré-Transplante
11.
J Anesth ; 37(1): 13-22, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36220948

RESUMO

PURPOSE: Postoperative delirium is one of the most common complications after cardiovascular surgery in older adults. Benzodiazepines are a reported risk factor for delirium; however, there are no studies investigating remimazolam, a novel anesthetic agent. Therefore, we prospectively investigated the effect of remimazolam on postoperative delirium. METHODS: We included elective cardiovascular surgery patients aged ≥ 65 years at Hamamatsu University Hospital between August 2020 and February 2022. Patients who received general anesthesia with remimazolam were compared with those who received other anesthetics (control group). The primary outcome was delirium within 5 days after surgery. Secondary outcomes were delirium during intensive care unit stay and hospitalization, total duration of delirium, subsyndromal delirium, and differences in the Mini-Mental State Examination scores from preoperative to postoperative days 2 and 5. To adjust for differences in the groups' baseline covariates, we used stabilized inverse probability weighting as the primary analysis and propensity score matching as the sensitivity analysis. RESULTS: We enrolled 200 patients; 78 in the remimazolam group and 122 in the control group. After stabilized inverse probability weighting, 30.3% of the remimazolam group patients and 26.6% of the control group patients developed delirium within 5 days (risk difference, 3.8%; 95% confidence interval -11.5% to 19.1%; p = 0.63). The secondary outcomes did not differ significantly between the groups, and the sensitivity analysis results were similar to those for the primary analysis. CONCLUSION: Remimazolam was not significantly associated with postoperative delirium when compared with other anesthetic agents.


Assuntos
Anestésicos , Delírio , Delírio do Despertar , Humanos , Idoso , Delírio do Despertar/complicações , Complicações Pós-Operatórias , Estudos Prospectivos , Delírio/etiologia , Benzodiazepinas
12.
Environ Monit Assess ; 195(12): 1437, 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37940732

RESUMO

To clarify the characteristics of compounds with strong or weak nitrification inhibition in sewage, 64 organic compounds including compounds registered in Pollutant Release and Transfer Register (PRTR) were evaluated in terms of their chemical structures and molecular weights. Nineteen compounds showed strong nitrification inhibition by testing with Nitrosomonas europaea. Compounds with thioamide structures had the lowest median value of EC50 (0.017 mg/L), followed by those with alkyne structures (0.121 mg/L), chlorophenol structures (0.300 mg/L), and then azole structures (0.365 mg/L). In contrast, 33 of the 64 compounds showed weak nitrification inhibition at a concentration of 10 mg/L, 27 of which were categorized into three main groups: long-chain alcohol structures, alkyne structures with a phenyl group, and aromatic structures. Most compounds with strong nitrification inhibition had a low molecular weight (MW) from 50 to 200. Meanwhile, the proportion of compounds with weak nitrification inhibition tended to be greater with increasing MW and such compounds were predominant at higher molecular weights above 300. The correlations of results derived from tests of nitrification inhibition based on ISO 9509 and N. europaea showed that 24 out of 30 compounds provided results that were highly correlated between these tests (R = 0.85), while 4 compounds with chlorophenol structures and 2 compounds with alkyne structures showed weaker inhibition rates in the ISO 9509 test than in the N. europaea test. Our results indicate that the magnitude of nitrification inhibition depends on MW in addition to the chemical structure, which is helpful in the search for the cause of nitrification inhibition in wastewater treatment plants.


Assuntos
Clorofenóis , Esgotos , Nitrificação , Reatores Biológicos , Monitoramento Ambiental , Alcinos , Oxirredução
13.
J Phys Ther Sci ; 35(1): 70-74, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36628139

RESUMO

[Purpose] This study aimed to investigate the prevalence of frailty among community-dwelling elderly females, and to examine its relation to motor function and the main risk factors of frailty. [Participants and Methods] The participants were 67 community-dwelling elderly females, aged 76.2 ± 7.7 years. We performed measurements of physical parameters, motor functions (such as grip strength), timed up and go test (TUG), walking speed, and frailty (measured using the Kihon Checklist [KCL]). [Results] KCL scores were 31.3%, 31.3%, and 37.3% in the frailty, pre-frailty, and robust groups, respectively. The frailty group was older than the pre-frailty and robust groups. Additionally, the different groups showed significant differences in grip strength, TUG, and walking speed. The highest median KCL score was for depression, followed by physical function. As a results, frailty was evident even among health-conscious elderly people. [Conclusion] It is essential to identify frailty at an early stage and identify its preventive factors, in order to extend the healthy life expectancy of the local population.

14.
Plant Cell Physiol ; 63(10): 1500-1509, 2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-35921240

RESUMO

We recently suggested that chloroplast triosephosphate isomerase (cpTPI) has moderate control over the rate of CO2 assimilation (A) at elevated CO2 levels via the capacity for triose phosphate utilization (TPU) in rice (Oryza sativa L.) from its antisense-suppression study. In the present study, the effects of cpTPI overexpression on photosynthesis were examined in transgenic rice plants overexpressing the gene encoding cpTPI. The amounts of cpTPI protein in the two lines of transgenic plants were 4.8- and 12.1-folds higher than in wild-type plants, respectively. The magnitude of the increase approximately corresponded to the increase in transcript levels of cpTPI. A at CO2 levels of 100 and 120 Pa increased by 6-9% in the transgenic plants, whereas those at ambient and low CO2 levels were scarcely affected. Similar increases were observed for TPU capacity estimated from the CO2 response curves of A. These results indicate that the overexpression of cpTPI marginally improved photosynthesis at elevated CO2 levels via improvement in TPU capacity in rice. However, biomass production at a CO2 level of 120 Pa did not increase in transgenic plants, suggesting that the improvement in photosynthesis by cpTPI overexpression was not sufficient to improve biomass production in rice.


Assuntos
Oryza , Oryza/genética , Oryza/metabolismo , Dióxido de Carbono/metabolismo , Triose-Fosfato Isomerase/genética , Triose-Fosfato Isomerase/metabolismo , Fotossíntese , Cloroplastos/metabolismo , Plantas Geneticamente Modificadas/genética
15.
Hepatology ; 73(6): 2455-2467, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33151580

RESUMO

BACKGROUND AND AIMS: Acute liver failure (ALF) is a rare but dramatic clinical syndrome characterized by massive hepatic necrosis leading to multiorgan failure. It is difficult to predict the outcomes in patients with ALF using existing prognostic models. We aimed to analyze hepatic perfusion using contrast-enhanced ultrasound and Doppler ultrasound in patients with ALF and investigate its utility as a prognostic biomarker. APPROACH AND RESULTS: In this prospective observational study, 208 patients with acute liver injury/ALF were enrolled from 2015 to 2019. We evaluated 50 consecutive patients with ALF with Doppler ultrasound and contrast-enhanced ultrasound performed on admission. The cases were divided into the following two groups: survivors (recovered without surgical intervention) and nonsurvivors (died of ALF or underwent liver transplantation). The time to peak and peak intensity of hepatic artery, portal vein, hepatic vein, and liver parenchyma were calculated using the time-intensity curve analysis. The hepatic artery (HA) resistive index was calculated using the fast Fourier transform analysis of Doppler ultrasound. The time interval (TI) between the time to peak of HA and liver parenchyma (LP) was significantly shorter in the nonsurvivors than in the survivors (P < 0.0001). The area under the receiver operating curve values for TI (HA, LP), Japanese scoring system, HE prediction model, Model for End-Stage Liver Disease score, and King's College Hospital criteria for the prediction of poor prognosis were 0.953, 0.914, 0.861, 0.816, and 0.731, respectively. The most appropriate cutoff value of TI (HA, LP) was 6.897 seconds; the sensitivity, specificity, positive and negative predictive values were 94.4%, 90.6%, 85.0%, and 96.7%, respectively. CONCLUSIONS: TI (HA, LP) accurately predicts the outcome in patients with ALF and may be useful in clinical decision making.


Assuntos
Tempo de Circulação Sanguínea/métodos , Circulação Hepática , Falência Hepática Aguda , Fígado , Imagem de Perfusão/métodos , Ultrassonografia Doppler/métodos , Meios de Contraste/farmacologia , Humanos , Aumento da Imagem/métodos , Japão/epidemiologia , Fígado/irrigação sanguínea , Fígado/diagnóstico por imagem , Falência Hepática Aguda/diagnóstico , Falência Hepática Aguda/mortalidade , Falência Hepática Aguda/fisiopatologia , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Análise de Sobrevida
16.
Plant Physiol ; 185(1): 108-119, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33631807

RESUMO

Rubisco limits C3 photosynthesis under some conditions and is therefore a potential target for improving photosynthetic efficiency. The overproduction of Rubisco is often accompanied by a decline in Rubisco activation, and the protein ratio of Rubisco activase (RCA) to Rubisco (RCA/Rubisco) greatly decreases in Rubisco-overproducing plants (RBCS-ox). Here, we produced transgenic rice (Oryza sativa) plants co-overproducing both Rubisco and RCA (RBCS-RCA-ox). Rubisco content in RBCS-RCA-ox plants increased by 23%-44%, and RCA/Rubisco levels were similar or higher than those of wild-type plants. However, although the activation state of Rubisco in RBCS-RCA-ox plants was enhanced, the rates of CO2 assimilation at 25°C in RBCS-RCA-ox plants did not differ from that of wild-type plants. Alternatively, at a moderately high temperature (optimal range of 32°C-36°C), the rates of CO2 assimilation in RBCS-ox and RBCS-RCA-ox plants were higher than in wild-type plants under conditions equal to or lower than current atmospheric CO2 levels. The activation state of Rubisco in RBCS-RCA-ox remained higher than that of RBCS-ox plants, and activated Rubisco content in RCA overproducing, RBCS-ox, RBCS-RCA-ox, and wild-type plants was highly correlated with the initial slope of CO2 assimilation against intercellular CO2 pressures (A:Ci) at 36°C. Thus, a simultaneous increase in Rubisco and RCA contents leads to enhanced photosynthesis within the optimal temperature range.


Assuntos
Aclimatação/fisiologia , Dióxido de Carbono/metabolismo , Temperatura Alta , Oryza/metabolismo , Fotossíntese/fisiologia , Proteínas de Plantas/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Aclimatação/genética , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Oryza/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Ribulose-Bifosfato Carboxilase/genética
17.
Photosynth Res ; 153(1-2): 83-91, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35635654

RESUMO

As chloroplast phosphoglycerate kinase (cpPGK) is one of the enzymes which has the highest capacity among the Calvin-Benson cycle enzymes, it has not been regarded as a determinant for photosynthetic capacity. However, it was reported that the rate of CO2 assimilation decreased under high irradiance and normal [CO2] levels in the Arabidopsis cpPGK-knockdown mutant, implying that cpPGK has a control over photosynthetic capacity at a normal [CO2] level. In the present study, the contribution of cpPGK to photosynthetic capacity was evaluated in transgenic rice plants with decreased amounts of cpPGK protein under high irradiance and various [CO2] levels. The gene encoding cpPGK was suppressed using RNA interference techniques. Two lines of transgenic plants, Pi3 and Pi5, in which the amount of cpPGK protein decreased to 21% and 76% of that in wild-type plants, respectively, were obtained. However, there was no substantial difference in the rates of CO2 assimilation between wild-type and transgenic plants. The rates of CO2 assimilation decreased only slightly at elevated [CO2] levels in the transgenic line Pi3 and did not differ between wild-type plants and the transgenic line Pi5, irrespective of [CO2] level. These results clearly indicate that cpPGK does not have a strong control over photosynthetic capacity at various [CO2] levels in rice.


Assuntos
Arabidopsis , Oryza , Arabidopsis/genética , Arabidopsis/metabolismo , Dióxido de Carbono/metabolismo , Cloroplastos/metabolismo , Oryza/genética , Oryza/metabolismo , Fosfoglicerato Quinase/genética , Fosfoglicerato Quinase/metabolismo , Fosfoglicerato Quinase/farmacologia , Fotossíntese , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo
18.
Electrophoresis ; 43(12): 1347-1356, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35338790

RESUMO

Malaria is a serious disease caused by Plasmodium parasites that infect red blood cells (RBCs). This paper presents the continuous separation of malaria-infected RBCs (iRBCs) from normal blood cells. The proposed method employed the discrete dielectrophoresis (DEP) in a microfluidic device with interdigitated electrodes. Our aim is to treat a sample having high concentration of cells to realize high throughput and to prevent the clogging of the microchannel with the use of the discrete DEP. The discrete DEP force for deflecting cells in the device was controlled by adjusting the magnitude, frequency, and duty cycle of the applied voltage. The effectiveness of the proposed method was demonstrated by separating the malaria-infected cells in samples having a cell concentration of 106 cells/µl. From experimental results, we determined the enrichment that is needed to enhance the detection in the case of low parasitemia. The enrichment of the infected cells at the device output was 3000 times as high as that of the input containing 1 infected cell to 106 normal cells. Therefore, the proposed method is highly effective and can significantly facilitate the detection of the infected cells for the identification of Malaria patients.


Assuntos
Malária , Técnicas Analíticas Microfluídicas , Separação Celular/métodos , Eletrodos , Eletroforese/métodos , Eritrócitos , Humanos , Dispositivos Lab-On-A-Chip
19.
J Exp Bot ; 73(8): 2589-2600, 2022 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-35134146

RESUMO

Fragility of photosystem I has been observed in transgenic rice plants that overproduce Rubisco activase (RCA). In this study, we examined the effects of RCA overproduction on the sensitivity of PSI to photoinhibition in three lines of plants overexpressing RCA (RCA-ox). In all the RCA-ox plants the quantum yield of PSI [Y(I)] decreased whilst in contrast the quantum yield of acceptor-side limitation of PSI [Y(NA)] increased, especially under low light conditions. In the transgenic line with the highest RCA content (RCA-ox 1), the quantum yield of PSII [Y(II)] and CO2 assimilation also decreased under low light. When leaves were exposed to high light (2000 µmol photon m-2 s-1) for 60 min, the maximal activity of PSI (Pm) drastically decreased in RCA-ox 1. These results suggested that overproduction of RCA disturbs PSI electron transport control, thus increasing the susceptibility of PSI to photoinhibition. When flavodiiron protein (FLV), which functions as a large electron sink downstream of PSI, was expressed in the RCA-ox 1 background (RCA-FLV), PSI and PSII parameters, and CO2 assimilation were recovered to wild-type levels. Thus, expression of FLV restored the robustness of PSI in RCA-ox plants.


Assuntos
Oryza , Ribulose-Bifosfato Carboxilase , Dióxido de Carbono/metabolismo , Transporte de Elétrons , Oryza/metabolismo , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema I/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Ativador de Plasminogênio Tecidual/metabolismo
20.
Hepatol Res ; 52(4): 401-410, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34989069

RESUMO

AIM: Hepatic encephalopathy (HE) development is crucial in liver transplantation for patients with acute liver injury (ALI) and failure (ALF); to predict HE development, the Japan Hepatic Encephalopathy Prediction (JHEP) model, calculated using age, etiology, prothrombin time (PT), and total bilirubin, was established in 2004, and a referral system to the liver center was implemented using the JHEP model from April 2004. METHODS: The JHEP model's ability to predict HE development in 460 consecutive patients with ALI between April 2004 and January 2021 using data from the referral system was evaluated, and the JHEP model was revised. RESULTS: During the observation period, 7.8% patients developed HE. There was no difference in the proportion of HE development among the etiologies. In the Hosmer-Lemeshow test for HE development prediction, the JHEP model, revised JHEP (rJHEP) model, which was calculated without etiology data, and the modified JHEP model, which used the PT international ratio instead of PT in the rJHEP model, were good fitting models. Upon 30% random sampling from the total patients 60 times, the receiver operating curve analysis of both JHEP and rJHEP models for HE development was performed in all the datasets. The area under the curve of the JHEP model was subtracted from that of the rJHEP model (95% confidential interval, 0.000516-0.01793). CONCLUSIONS: The referral system using the JHEP model reduced the difference in the risk for HE development among each etiology; the rJHEP model had a better prediction ability for HE development than the JHEP model.

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