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1.
J Am Soc Nephrol ; 35(2): 135-148, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38044490

RESUMO

SIGNIFICANCE STATEMENT: In this study, we demonstrate that a common, low-cost compound known as octanedioic acid (DC 8 ) can protect mice from kidney damage typically caused by ischemia-reperfusion injury or the chemotherapy drug cisplatin. This compound seems to enhance peroxisomal activity, which is responsible for breaking down fats, without adversely affecting mitochondrial function. DC 8 is not only affordable and easy to administer but also effective. These encouraging findings suggest that DC 8 could potentially be used to assist patients who are at risk of experiencing this type of kidney damage. BACKGROUND: Proximal tubules are rich in peroxisomes, which are damaged during AKI. Previous studies demonstrated that increasing peroxisomal fatty acid oxidation (FAO) is renoprotective, but no therapy has emerged to leverage this mechanism. METHODS: Mice were fed with either a control diet or a diet enriched with dicarboxylic acids, which are peroxisome-specific FAO substrates, then subjected to either ischemia-reperfusion injury-AKI or cisplatin-AKI models. Biochemical, histologic, genetic, and proteomic analyses were performed. RESULTS: Both octanedioic acid (DC 8 ) and dodecanedioic acid (DC 12 ) prevented the rise of AKI markers in mice that were exposed to renal injury. Proteomics analysis demonstrated that DC 8 preserved the peroxisomal and mitochondrial proteomes while inducing extensive remodeling of the lysine succinylome. This latter finding indicates that DC 8 is chain shortened to the anaplerotic substrate succinate and that peroxisomal FAO was increased by DC 8 . CONCLUSIONS: DC 8 supplementation protects kidney mitochondria and peroxisomes and increases peroxisomal FAO, thereby protecting against AKI.


Assuntos
Injúria Renal Aguda , Ácidos Dicarboxílicos , Suplementos Nutricionais , Traumatismo por Reperfusão , Animais , Humanos , Camundongos , Injúria Renal Aguda/prevenção & controle , Injúria Renal Aguda/patologia , Cisplatino , Ácidos Dicarboxílicos/administração & dosagem , Ácidos Graxos , Proteômica , Traumatismo por Reperfusão/prevenção & controle , Traumatismo por Reperfusão/patologia
2.
J Am Chem Soc ; 146(29): 20122-20132, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-38985988

RESUMO

Structure-function relationships of supported metal nanoparticle catalysts in the CO-assisted oxidation of ethane to ethanol were investigated. A rutile TiO2-supported Pt nanoparticle catalyst exhibited the highest ethanol production rate and selectivity. During the reaction, sequential changes in the geometric/electronic states and the particle size of the Pt nanoparticles were observed. The comparison of the catalytic performances of model catalysts with controlled metal-support interactions revealed that Pt0 nanoparticles of 2-3 nm with a high fraction of the surface Ptδ+ species are highly active for the oxidation of ethane to ethanol. The coadded CO plays a pivotal role not only in tuning the oxidation state of the surface Pt but also in producing H2O2, which is the true oxidant for the reaction. The supported Pt nanoparticle uses in situ-generated H2O2 to activate ethane, where the C2H5OOH intermediate is formed through a nonradical mechanism and subsequently converted to C2H5OH. This reaction occurs even at 50 °C with an apparent activation energy of 32 kJ mol-1. The present study sheds light on the usefulness of surface-engineered Pt nanoparticles for the low-temperature oxidation of ethane to ethanol.

3.
Kidney Int ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38901605

RESUMO

Vascularization plays a critical role in organ maturation and cell-type development. Drug discovery, organ mimicry, and ultimately transplantation hinge on achieving robust vascularization of in vitro engineered organs. Here, focusing on human kidney organoids, we overcame this hurdle by combining a human induced pluripotent stem cell (iPSC) line containing an inducible ETS translocation variant 2 (ETV2) (a transcription factor playing a role in endothelial cell development) that directs endothelial differentiation in vitro, with a non-transgenic iPSC line in suspension organoid culture. The resulting human kidney organoids show extensive endothelialization with a cellular identity most closely related to human kidney endothelia. Endothelialized kidney organoids also show increased maturation of nephron structures, an associated fenestrated endothelium with de novo formation of glomerular and venous subtypes, and the emergence of drug-responsive renin expressing cells. The creation of an engineered vascular niche capable of improving kidney organoid maturation and cell type complexity is a significant step forward in the path to clinical translation. Thus, incorporation of an engineered endothelial niche into a previously published kidney organoid protocol allowed the orthogonal differentiation of endothelial and parenchymal cell types, demonstrating the potential for applicability to other basic and translational organoid studies.

4.
Angew Chem Int Ed Engl ; : e202411969, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39252177

RESUMO

The efficient capture of low-pressure CO2 remains a significant challenge due to the lack of established multi-complexation of CO2 to active sites in microporous materials. In this study, we introduce a novel concept of reversible multi-complexation of CO2 to alkaline earth metal (AEM) ion pairs, utilizing a host site in ferrierite-type zeolite (FER). This unique site constrains two AEM ions in proximity, thereby enhancing and isotopically spreading their electrostatic potentials within the zeolite cavity. This electrostatic potential-engineered micropore can trap up to four CO2 molecules, forming M2+-(CO2)n-M2+ (n=0-4, M=Ca, Sr, Ba) complexes, where each CO2 molecule is stabilized by interactions between terminal oxygen (Ot) in CO2 and the AEM ions. Notably, the Ba2+ pair site exhibits higher thermodynamic stability for multiple adsorptions due to the optimal binding mode of Ba2+-Ot-Ba2+. Through high-accuracy energy calculations, we have established the relationship among structure, CO2 uptake, and operating temperature/pressure, demonstrating that the Ba2+ pair site can capture four CO2 molecules even at concentrations as low as 400 ppm and at 298 K. Three of the four molecules of CO2 trapped were removable at room temperature and under vacuum. The findings in the present study provide a new direction for developing efficient CO2 adsorbents.

5.
J Pharmacol Exp Ther ; 384(1): 197-204, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36273821

RESUMO

The cholesterol-conjugated heteroduplex oligonucleotide (Chol-HDO) is a double-stranded complex; it comprises an antisense oligonucleotide (ASO) and its complementary strand with a cholesterol ligand. Chol-HDO is a powerful tool for achieving target RNA knockdown in the brains of mice after systemic injection. Here, a quantitative model analysis was conducted to characterize the relationship between the pharmacokinetics (PK) and pharmacodynamics (PD), non-coding RNA metastasis-associated lung adenocarcinoma 1 (Malat1) RNA, of Chol-HDO, in a time-dependent manner. The established PK model could describe regional differences in the observed brain concentration-time profiles. Incorporating the PD model enabled the unique knockdown profiles in the brain to be explained in terms of the time delay after single dosing and enhancement following repeated dosing. Moreover, sensitivity analysis of PK exposure/persistency, target RNA turnover, and knockdown potency identified key factors for the efficient and sustained target RNA knockdown in the brain. The simulation of an adequate dosing regimen quantitatively supported the benefit of Chol-HDO in terms of achieving a suitable dosing interval. This was achieved via sufficient and sustained brain exposure and subsequent strong and sustained target RNA knockdown in the brain, even after systemic injection. The present study provides new insights into drug discoveries and development strategies for HDO in patients with neurogenic disorders. SIGNIFICANCE STATEMENT: The quantitative model analysis presented here characterized the PK/PD relationship of Chol-HDO, enabled its simulation under various conditions or assumptions, and identified key factors for efficient and sustained RNA knockdown, such as PK exposure and persistency. Chol-HDO appears to be an efficient drug delivery system for the systemic administration of desired drugs to brain targets.


Assuntos
Oligonucleotídeos , RNA , Camundongos , Animais , Barreira Hematoencefálica , Colesterol , DNA
6.
Clin Exp Nephrol ; 27(1): 55-65, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36190589

RESUMO

BACKGROUND: Mean corpuscular volume (MCV) and red cell distribution width (RDW), as well hemoglobin, are reported to be associated with mortality in various populations. However, associations between such hematological parameters and adverse outcomes in patients with CKD have not been sufficiently elucidated. METHODS: A total of 1,320 participants enrolled in the Fukushima CKD Cohort Study were examined to investigate associations between hematological parameters of anemia (MCV and RDW) and adverse outcomes, such as ESKD, all-cause death, and cardiovascular events, in patients with non-dialysis-dependent CKD. Baseline hematological parameters were grouped as follows: hemoglobin into 3 categories (< 11.0 g/dL, 11.0 ≤ - < 13.0 g/dL [reference], and ≥ 13.0 g/dL); MCV into 5 categories (< 90 fL, ≥ 90 - < 94 fL [reference], ≥ 94 - < 98 fL, ≥ 98 - < 102 fL, and ≥ 102 fL); and RDW into 2 categories (< 13.6% [reference] vs ≥ 13.6%). RESULTS: During the median observational period of 4.7 years, 120 patients developed ESKD, 160 developed cardiovascular events, and 122 died. Hemoglobin < 11 g/dL (hazard ratio [HR] 1.56, 95% confidence interval [CI], 1.00-2.42), MCV < 90 fL (HR 2.01, 95% CI 1.14-3.54), and RDW ≥ 13.6% (HR 1.57, 95% CI 1.01-2.42) were significantly associated with higher risks of ESKD. Hemoglobin < 11 g/dL, MCV ≥ 98 fL, and RDW ≥ 13.6% were significantly associated with higher risks of all-cause death. No significant associations between hematological parameters and risk of cardiovascular events were confirmed. CONCLUSION: In patients with non-dialysis-dependent CKD, MCV, RDW, and hemoglobin were associated with increased risks of ESKD and all-cause mortality.


Assuntos
Anemia , Doenças Cardiovasculares , Insuficiência Renal Crônica , Humanos , Estudos de Coortes , Anemia/diagnóstico , Anemia/epidemiologia , Índices de Eritrócitos , Hemoglobinas/análise , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/epidemiologia , Prognóstico , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/etiologia
7.
Transfusion ; 61(10): 2825-2829, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34369596

RESUMO

BACKGROUND: In this study, we identified a novel glycophorin variant (GP.MOT) in a Mia -positive Japanese blood donor. The proband with this glycophorin variant was discovered by antigen screening of samples from 475,493 Japanese blood donors using monoclonal anti-Mia . STUDY DESIGN AND METHODS: Standard serological techniques and flow cytometry were performed. GP.MOT RBCs were examined by immunoblotting using anti-GPA, anti-MUT or anti-Mur. Genome DNA was extracted from whole blood, and the GYPA/GYPB was analyzed by polymerase chain reactions and Sanger sequencing. RESULTS: The MNS blood group of the proband was M + N + w S-s + with the presence of other low-frequency antigens including Mia , Mur, MUT, and KIPP. A 43-kDa molecule, which is almost equivalent in size to glycophorin A (GPA), was identified by immunoblotting using monoclonal anti-MUT and anti-Mur. Sanger sequencing clearly indicated that the proband had two different GYPA*M alleles at SNP rs62334651 (GYPA*M232 + 55A and GYPA*M232 + 55G), as well as a GYP(B-A) hybrid allele (GYP*MOT) with breakpoints located on pseudoexon 3 of GYPB from c.210 to c.219. DISCUSSION: We identified a hybrid glycophorin GP.MOT with the deduced unique amino acid sequence GPB (20-45)-GPΨB (46-70)-GPA (71-149), which has not been previously reported.


Assuntos
Glicoforinas/genética , Alelos , Sequência de Aminoácidos , Sequência de Bases , Doadores de Sangue , Variação Genética , Humanos , Japão , Sistema do Grupo Sanguíneo MNSs/genética , Análise de Sequência de DNA
8.
Clin Exp Nephrol ; 25(2): 191-199, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33025233

RESUMO

BACKGROUND: Serial management of renal anemia using continuous erythropoietin receptor activator (CERA) throughout the peritoneal dialysis initiation period has rarely been reported. We investigated the efficacy and dosage of CERA treatment from pre- to post-peritoneal dialysis initiation for anemia management in patients with end-stage renal disease. METHODS: Twenty-six patients (13 men; mean age 60.9 years) who started peritoneal dialysis between April 2012 and April 2018 were investigated. Serial changes in hemoglobin levels, transferrin saturation and ferritin levels, CERA dosage, and the erythropoietin resistance index (ERI) over a 48 week period were retrospectively examined. RESULTS: Mean hemoglobin levels increased significantly from 10.5 g/dL at 24 weeks prior to the peritoneal dialysis initiation to 11.5 g/dL at 4 weeks post-initiation. The proportion of patients with hemoglobin levels ≥ 11 g/dL increased significantly after peritoneal dialysis initiation. The mean CERA dosage was 57.0 µg/month at 24 weeks prior to dialysis initiation, 86.5 µg/month at initiation, and 72.0 µg/month at 4 weeks post-initiation. Thus, the dosage tended to increase immediately before peritoneal dialysis initiation and then decreased thereafter. Hemoglobin levels were significantly lower, while the CERA dosage for maintaining hemoglobin levels and ERI tended to be higher at dialysis initiation in patients with diabetes than in those without diabetes. CONCLUSION: Treatment with CERA prior to and during the peritoneal dialysis initiation achieved fairly good anemia management in patients with and without diabetes. The CERA dosage could be reduced in patients without diabetes after dialysis initiation.


Assuntos
Anemia/tratamento farmacológico , Eritropoetina/uso terapêutico , Falência Renal Crônica/complicações , Diálise Peritoneal , Polietilenoglicóis/uso terapêutico , Adulto , Idoso , Feminino , Hemoglobinas/análise , Humanos , Falência Renal Crônica/terapia , Masculino , Pessoa de Meia-Idade
9.
Clin Exp Nephrol ; 25(4): 410-417, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33411113

RESUMO

BACKGROUND: Serum potassium disorders, commonly observed in chronic kidney disease (CKD), are reportedly associated with higher mortality, but their impact on renal outcomes is still controversial. METHODS: The present study used the longitudinal data of the Fukushima CKD cohort study to investigate the relationships between hypokalemia and hyperkalemia and adverse outcomes such as renal outcomes and all-cause mortality in Japanese patients with non-dialysis-dependent CKD. The study involved 1330 CKD patients followed-up for 2.8 years. The primary endpoint of the present study was a kidney event, defined as a combination of doubling of baseline serum creatinine and end-stage kidney disease. RESULTS: Hyperkalemia (≥ 5.0 mmol/L) was noted in 10.6% and hypokalemia (< 4.0 mmol/L) in 16.4% of the study population. Significant U-shaped associations were observed between potassium levels and both kidney events and all-cause mortality on univariate Cox regression analyses. After adjustment for covariates, both hypokalemia and hyperkalemia were significantly associated with an increased risk of kidney events, with the lowest risk at a serum potassium of 4.0-4.4 mmol/L. Compared with a reference level of 4.0-4.4 mmol/L, the adjusted hazard ratio for kidney events was 2.49 (1.33-4.66) for serum potassium < 4.0 mmol/L, 1.72 (1.00-2.96) for 4.5-4.9 mmol/L, and 2.16 (1.15-4.06) for ≥ 5.0 mmol/L. There was no significant association between serum potassium levels and mortality after multivariate adjustment. CONCLUSION: Hypokalemia and hyperkalemia were associated with an increased risk of CKD progression, but not with mortality in Japanese patients with non-dialysis-dependent CKD.


Assuntos
Hiperpotassemia/epidemiologia , Hipopotassemia/epidemiologia , Potássio/sangue , Insuficiência Renal Crônica/epidemiologia , Idoso , Biomarcadores/sangue , Causas de Morte , Progressão da Doença , Feminino , Humanos , Hiperpotassemia/sangue , Hiperpotassemia/diagnóstico , Hiperpotassemia/mortalidade , Hipopotassemia/sangue , Hipopotassemia/diagnóstico , Hipopotassemia/mortalidade , Incidência , Japão , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/mortalidade , Medição de Risco , Fatores de Risco , Fatores de Tempo
10.
Clin Exp Nephrol ; 24(8): 725-733, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32285213

RESUMO

BACKGROUND: In patients with chronic kidney disease (CKD), dysbiosis in the gastrointestinal microbiome is thought to be associated with increased production of uremic toxins, such as indoxyl sulfate (IS) and p-cresyl sulfate (PCS). Sucroferric oxyhydroxide (SFO), an iron-based phosphate binder, may affect the gastrointestinal microbiome and the production of uremic toxins. We aimed to examine whether SFO administration affected distribution of gastrointestinal microbiome and serum uremic toxin levels in CKD patients undergoing hemodialysis. METHODS: In this single-center, open-label, interventional study, 18 maintenance hemodialysis patients with hyperphosphatemia were prescribed with SFO. We collected serum samples before and after 3 months of administration, and serum levels of IS and PCS were measured. A control group of 20 hemodialysis patients without SFO was evaluated. We evaluated gastrointestinal microbiome of patients pre- and post-SFO administration by 16S rDNA sequencing and bioinformatics analysis. RESULTS: Serum IS and PCS levels were significantly elevated after administration of SFO (IS before 2.52 ± 1.60 mg/dl vs. after 3.13 ± 1.51 mg/dl, P = 0.008; PCS before 2.32 ± 2.44 mg/dl vs. after 3.45 ± 2.11 mg/dl, P = 0.002), while serum IS and PCS levels did not change in the control group. Microbiome analysis in the SFO group showed no significant change in diversity and major components in phylum, class, order, family, gene, and species. CONCLUSION: Administration of SFO increased the serum levels of IS and PCS with no change of major components of gastrointestinal microbiome.


Assuntos
Disbiose/tratamento farmacológico , Compostos Férricos/uso terapêutico , Microbioma Gastrointestinal/efeitos dos fármacos , Insuficiência Renal Crônica/microbiologia , Sacarose/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Cresóis/sangue , Combinação de Medicamentos , Disbiose/etiologia , Fezes/microbiologia , Compostos Férricos/farmacologia , Humanos , Indicã/sangue , Pessoa de Meia-Idade , Diálise Renal , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/terapia , Sacarose/farmacologia , Ésteres do Ácido Sulfúrico/sangue
11.
Clin Exp Nephrol ; 24(5): 427-434, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31875937

RESUMO

BACKGROUND: Inadequate blood pressure control is one of the important causes of chronic kidney disease (CKD), but only a limited number of reports have examined blood pressure control in Japanese patients with pre-dialysis CKD. Differences in blood pressure control due to underlying renal disease in pre-dialysis patients with CKD were investigated in the present study using the baseline data of the Fukushima CKD cohort study. METHODS: The study involved 1351 CKD patients, classified by underlying disease of primary renal disease, hypertensive nephropathy, diabetic nephropathy, other nephropathies, or unknown. Target blood pressure of CKD patients was defined as < 130/80 mmHg in patients under 75 years old with diabetes and/or proteinuria, and < 140/90 mmHg in other patients. RESULTS: The achievement rate of target systolic blood pressure was lower in the diabetic and hypertensive nephropathy groups than in the primary renal disease group (33.3%, 46.0% vs. 68.1%, p < 0.001). However, the number of antihypertensive medications increased in the diabetic and hypertensive nephropathy groups compared to the primary renal disease group (2.16, 2.04 vs. 1.55, p < 0.001). Inadequate blood pressure control was independently related to the underlying renal disease, with a significant difference between diabetic nephropathy and primary renal disease (odds ratio 3.19; 95% confidence interval, 2.16-4.69; p < 0.001). CONCLUSION: This study showed that blood pressure control differs by the underlying renal disease. Blood pressure control was poor especially in diabetic nephropathy despite multidrug combination antihypertensive treatment. It is necessary to verify whether strict blood pressure control improves patients' prognosis in diabetic nephropathy.


Assuntos
Pressão Sanguínea , Nefropatias Diabéticas/fisiopatologia , Hipertensão Renal/fisiopatologia , Hipertensão/fisiopatologia , Nefrite/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Idoso , Anti-Hipertensivos/uso terapêutico , Estudos Transversais , Nefropatias Diabéticas/complicações , Feminino , Glomerulonefrite/complicações , Glomerulonefrite/fisiopatologia , Humanos , Hipertensão/tratamento farmacológico , Hipertensão Renal/complicações , Japão , Masculino , Pessoa de Meia-Idade , Nefrite/complicações , Estudos Prospectivos , Insuficiência Renal Crônica/etiologia , Sístole
12.
Transfusion ; 59(7): 2429-2435, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31020675

RESUMO

BACKGROUND: Anti-KANNO, a broadly reactive RBC alloantibody, is found among some Japanese pregnant women, but the genetic basis of the corresponding antigen remains unclear. STUDY DESIGN AND METHODS: We integrated a statistical approach to identify the coding gene for KANNO antigen by conducting a genome-wide association study (GWAS) on four KANNO-negative individuals and 415 healthy Japanese. We also applied whole-exome sequencing to them and performed a replication study to confirm the identified genome variation using independent 14 KANNO-negative individuals. A monoclonal antibody-specific immobilization of erythrocyte antigens (MAIEA) assay was used to locate KANNO antigen on RBC-specific membrane protein. In vivo and in vitro binding assays of anti-KANNO were further applied to the cells expressing a candidate protein. RESULTS: The GWAS revealed a genome-wide significant association of chromosome 20p13 locus (p = 2.76E-08; odds ratio > 1000 [95% confidence interval = 48-23,674]). The identified single-nucleotide polymorphism located in an intronic region of the prion protein (PRNP) gene. Whole-exome sequencing revealed a missense variant in the PRNP gene (rs1800014, E219K), which is in linkage disequilibrium with the single-nucleotide polymorphism identified in the GWAS. All 18 KANNO-negative individuals possessed the homozygous genotype of the missense variant. The MAIEA assay using anti-KANNO and mouse antihuman prion protein showed a clear difference between KANNO-positive and KANNO-negative RBCs. Anti-KANNO showed direct binding to CHO-K1 cells expressing wild-type PRNP but not to those expressing E219K PRNP. CONCLUSION: We first identified the coding gene of the high-frequency antigen KANNO located in PRNP and the missense variation (E219K) that affects the seropositivity of the KANNO antigen, which were confirmed by PRNP overexpressed cells.


Assuntos
Antígenos de Grupos Sanguíneos/genética , Cromossomos Humanos Par 20/genética , Frequência do Gene , Genoma Humano , Glicoproteínas/genética , Polimorfismo de Nucleotídeo Único , Proteínas Priônicas/genética , Estudo de Associação Genômica Ampla , Humanos
13.
Inorg Chem ; 58(1): 327-338, 2019 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-30495931

RESUMO

Oxygenase reactivity toward selective partial oxidation of CH4 to CH3OH requires an atomic oxygen-radical bound to metal (M-O•: oxyl intermediate) that is capable of abstracting an H atom from the significantly strong C-H bond in CH4. Because such a reaction is frequently observed in metal-doped zeolites, it has been recognized that the zeolite provides an environment that stabilizes the M-O• intermediate. However, no experimental data of M-O• have so far been discovered in the zeolite; thus, little is known about the correlation among the state of M-O•, its reactivity for CH4, and the nature of the zeolite environment. Here, we report a combined spectroscopic and computational study of the room-temperature activation of CH4 over ZnII-O• in the MFI zeolite. One ZnII-O• species does perform H-abstraction from CH4 at room temperature. The resultant CH3• species reacts with the other ZnII-O• site to form the ZnII-OCH3 species. The H2O-assisted extraction of surface methoxide yields 29 µmol g-1 of CH3OH with a 94% selectivity. The quantum mechanics (QM)/molecular mechanics (MM) calculation determined the central step as the oxyl-mediated hydrogen atom transfer which requires an activation energy of only 10 kJ mol-1. On the basis of the findings in gas-phase experiments regarding the CH4 activation by the free [M-O•]+ species, the remarkable H-abstraction reactivity of the ZnII-O• species in zeolites was totally rationalized. Additionally, the experimentally validated QM/MM calculation revealed that the zeolite lattice has potential as the ligand to enhance the polarization of the M-O• bond and thereby enables to create effectively the highly reactive M-O• bond required for low-temperature activation of CH4. The present study proposes that tuning of the polarization effect of the anchoring site over heterogeneous catalysts is the valuable way to create the oxyl-based functionality on the heterogeneous catalyst.

14.
Phys Chem Chem Phys ; 19(36): 25105-25114, 2017 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-28880028

RESUMO

Understanding the exact position and the detailed role of the Al array in zeolites is essential for elucidating the origin of unique properties that can be derived from the metal-ion exchanged in zeolite samples and for designing zeolite materials with high efficiency in catalytic and adsorption processes. In this work, we investigate, for the first time, the important role of the Al array in the reactivity observed on the metal-ion exchanged in zeolites on the basis of the calculation method by utilizing the spontaneous heterolytic cleavage of H2 observed experimentally on the Zn2+-ion exchanged in MFI-type zeolites (Zn2+-MFI) as the model reaction. In the case of calculation, two main types of models for considering the Al positions in MFI-type zeolites were adopted: in the first type, the Al atoms with appropriate distances are aligned in the circumferential direction of the straight channel (abbreviated as a circumferentially arrayed Al-Al site); in the second type, the nearest neighbouring Al atoms with appropriate distances are directed toward the straight channel axis (abbreviated as a channel directionally arrayed Al-Al site). Results indicated that the Al-array direction governs the reactivity of Zn2+-MFI. The former type of array well explains the experimental fact that spontaneous and irreversible heterolysis of H2 takes place on Zn2+-MFI, even at room temperature, whereas the latter type of array is less reactive; high activation energy is required for the heterolytic cleavage of H2 (ca. >70 kJ mol-1). A detailed analysis of the geometric and electronic structures of a series of Zn2+-MFI models with various Al-array directions clarified the following facts: the circumferentially arrayed Al-Al site induces an inevitable environment around the Zn2+ site, with the simultaneous existence of both a Lewis acid point (coordinatively unsaturated and distorted Zn2+) and a Lewis base point (the lattice oxygen atom juxtaposed with exchanged Zn2+, which participates in the activation of H2: OjL). It is the circumferentially arrayed Al-Al atoms that confer acidic and basic nature on the metal ion and the lattice oxygen atom (OjL), and ultimately trigger the heterolytic dissociation of H2, even at 300 K.

15.
Angew Chem Int Ed Engl ; 56(33): 9715-9718, 2017 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-28608610

RESUMO

Although a terminal oxyl species bound to certain metal ions is believed to be the intermediate for various oxidation reactions, such as O-O bond generation in photosystem II (PSII), such systems have not been characterized. Herein, we report a stable ZnII -oxyl species induced by an MFI-type zeolite lattice and its reversible reactivity with O2 at room temperature. Its intriguing characteristics were confirmed by in situ spectroscopic studies in combination with quantum-chemical calculations, namely analyses of the vibronic Franck-Condon progressions and the ESR signal features of both ZnII -oxyl and ZnII -ozonide species formed during this reversible process. Molecular orbital analyses revealed that the reversible reaction between a ZnII -oxyl species and an O2 molecule proceeds via a radical O-O coupling-decoupling mechanism; the unpaired electron of the oxyl species plays a pivotal role in the O-O bond generation process.

16.
Immunohematology ; 31(1): 24-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26308467

RESUMO

Differentiation of ABO mosaics from chimeras is performed using flow cytometry (FCM) analysis. Although mosaics and chimeras have been distinguished by presence or absence of clear resolution using FCM analysis, the lack of quantitative metrics and definitive criteria for this differentiation has made some cases difficult to differentiate. In this study, therefore, we attempted to establish a definitive and quantitative criterion for this differentiation. When FCM histogram gates for group "A" or "B" antigen-negative and -positive red blood cells (RBCs) were set such that group O RBCs were classified as 99 percent negative and group A or B RBCs as 99 percent positive, the percentages of RBCs in the middle region of six chimeras and 23 mosaics (12 A mosaics and 11 B mosaics) were 0.1-0.6 percent and 7.0-19.0 percent, respectively. This results suggested that ABO mosaics and chimeras can be unambiguously differentiated when the cutoff point of the intermediate region is set to 1 percent.


Assuntos
Sistema ABO de Grupos Sanguíneos/imunologia , Tipagem e Reações Cruzadas Sanguíneas/métodos , Citometria de Fluxo/métodos , Mosaicismo , Feminino , Humanos , Masculino
17.
J Neurochem ; 128(2): 246-55, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24117996

RESUMO

Cholinergic neurons in the CNS are involved in synaptic plasticity and cognition. Both muscarinic and nicotinic acetylcholine receptors (nAChRs) influence plasticity and cognitive function. The mechanism underlying nAChR-induced plasticity, however, has remained elusive. Here, we demonstrate morphological changes in dendritic spines following activation of α4ß2* nAChRs, which are expressed on glutamatergic pre-synaptic termini of cultured hippocampal neurons. Exposure of the neurons to nicotine resulted in a lateral enlargement of spine heads. This was abolished by dihydro-ß-erythroidine, an antagonist of α4ß2* nAChRs, but not by α-bungarotoxin, an antagonist of α7 nAChRs. Tetanus toxin or a mixture of 2-amino-5-phosphonovaleric acid and 6-cyano-7-nitroquinoxaline-2,3-dione, antagonists of NMDA- and AMPA-type glutamate receptors, blocked the nicotine-induced spine remodeling. In addition, nicotine exerted full spine-enlarging response in the post-synaptic neuron whose ß2 nAChR expression was knocked down. Finally, pre-treatment with nicotine enhanced the Ca(2+)-response of the neurons to glutamate. These data suggest that nicotine influences the activity of glutamatergic neurotransmission through the activation of pre-synaptic α4ß2 nAChRs, resulting in the modulation of spinal architecture and responsiveness. The present findings may represent one of the cellular mechanisms underlying cholinergic tuning of brain function. Activation of nicotinic acetylcholine receptors (nAChRs) in brain influences plasticity and cognition. Here, activation of α4ß2* nAChRs, which are expressed on glutamatergic presynaptic termini, results in the enlargement of dendritic spines through the modulation of the glutamatergic neurotransmission. The remodeled spinal architecture might be responsible for the change in responsiveness of neural circuitry, leading to cholinergic tuning of brain function.


Assuntos
Espinhas Dendríticas/efeitos dos fármacos , Hipocampo/citologia , Neurônios/efeitos dos fármacos , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Animais , Células Cultivadas , Espinhas Dendríticas/ultraestrutura , Glutamatos/metabolismo , Neurônios/ultraestrutura , Ratos , Ratos Sprague-Dawley
18.
Chem Commun (Camb) ; 60(34): 4597-4600, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38586897

RESUMO

We have found an efficient adsorption feature provided by an NaCaA-85 zeolite for N2O even at 298 K and at lower pressures: N2O adsorption capacities of 1.33 mmol g-1 and 4.69 mmol g-1 under respective pressures of 0.3 and at 100 Torr, respectively, indicating the best performance among adsorbent materials so far reported. These adsorption peculiarities will pave a new way for developing excellent materials working for adsorption/separation processes of N2O.

19.
bioRxiv ; 2024 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-39484612

RESUMO

Proximal tubular epithelial cells (PTECs) are particularly vulnerable to acute kidney injury (AKI). While fatty acids are the preferred energy source for PTECs via fatty acid oxidation (FAO), FAO-mediated H 2 O 2 production in mitochondria has been shown to be a major source of oxidative stress. We have previously shown that a mitochondrial flavoprotein, long-chain acyl-CoA dehydrogenase (LCAD), which catalyzes a key step in mitochondrial FAO, directly produces H 2 O 2 in vitro . Further we have established that loss of a lysine deacylase, Sirtuin 5 ( Sirt5 -/- ), induces hypersuccinylation and inhibition of mitochondrial FAO genes to stimulate peroxisomal FAO and to protect against AKI. However, the role of LCAD has yet to be determined. Mass spectrometry data acquisition revealed that LCAD is hypersuccinylated in Sirt5 -/- kidneys after AKI. Following two distinct models of AKI, cisplatin treatment or renal ischemia/reperfusion (IRI), LCAD knockout mice ( LCAD -/- ) demonstrated renoprotection against AKI. Specifically, LCAD -/- kidneys displayed mitigated renal tubular injury, decreased oxidative stress, preserved mitochondrial function, enhanced peroxisomal FAO, and decreased ferroptotic cell death. LCAD deficiency confers protection against two distinct models of AKI. This suggests a therapeutically attractive mechanism whereby preserved mitochondrial respiration as well as enhanced peroxisomal FAO by loss of LCAD mediates renoprotection against AKI.

20.
J Am Chem Soc ; 135(49): 18481-9, 2013 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-24224580

RESUMO

For the first time, the paramagnetic Zn(+) species was prepared successfully by the excitation with ultraviolet light in the region ascribed to the absorption band resulting from the 4s-4p transition of an atomic Zn(0) species encapsulated in an MFI-type zeolite. The formed species gives a specific electron spin resonance band at g = 1.998 and also peculiar absorption bands around 38,000 and 32,500 cm(-1) which originate from 4s-4p transitions due to the Zn(+) species with paramagnetic nature that is formed in MFI. The transformation process (Zn(0) → Zn(+)) was explained by considering the mechanism via the excited triplet state ((3)P) caused by the intersystem crossing from the excited singlet state ((1)P) produced through the excitation of the 4s-4p transition of an atomic Zn(0) species grafted in MFI by UV light. The transformation process was well reproduced with the aid of a density functional theory calculation. The thus-formed Zn(+) species which has the doublet spin state exhibits characteristic reaction nature at room temperature for an O2 molecule having a triplet spin state in the ground state, forming an η(1) type of Zn(2+)-O2(-) species. These features clearly indicate the peculiar reactivity of Zn(+) in MFI, whereas Zn(0)-(H(+))2MFI hardly reacts with O2 at room temperature. The bonding nature of [Zn(2+)-O2(-)] species was also evidenced by ESR measurements and was also discussed on the basis of the results obtained through DFT calculations.

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