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1.
J Am Chem Soc ; 146(2): 1701-1709, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38157406

RESUMEN

Mesoporous materials with crystalline frameworks have been widely explored in many fields due to their unique structure and crystalline feature, but accurate manipulations over crystalline scaffolds, mainly composed of uncontrolled polymorphs, are still lacking. Herein, we explored a controlled crystallization-driven monomicelle assembly approach to construct a type of uniform mesoporous TiO2 particles with atomically aligned single-crystal frameworks. The resultant mesoporous TiO2 single-crystal particles possess an angular shape ∼80 nm in diameter, good mesoporosity (a high surface area of 112 m2 g-1 and a mean pore size at 8.3 nm), and highly oriented anatase frameworks. By adjusting the evaporation rate during assembly, such a facile solution-processed strategy further enables the regulation of the particle size and mesopore size without the destruction of the oriented crystallites. Such a combination of ordered mesoporosity and crystalline orientation provides both effective mass and charge transportation, leading to a significant increase in the hydrogen generation rate. A maximum hydrogen evolution rate of 12.5 mmol g-1 h-1 can be realized, along with great stability under solar light. Our study is envisaged to extend the possibility of mesoporous single crystal growth to a range of functional ceramics and semiconductors toward advanced applications.

2.
Small ; 20(15): e2307378, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38009801

RESUMEN

The high-current-density Zn-air battery shows big prospects in next-generation energy technologies, while sluggish O2 reaction and diffusion kinetics barricade the applications. Herein, the sequential assembly is innovatively demonstrated for hierarchically mesoporous molybdenum carbides/carbon microspheres with a tunable thickness of mesoporous carbon layers (Meso-Mo2C/C-x, where x represents the thickness). The optimum Meso-Mo2C/C-14 composites (≈2 µm in diameter) are composed of mesoporous nanosheets (≈38 nm in thickness), which possess bilateral mesoporous carbon layers (≈14 nm in thickness), inner Mo2C/C layers (≈8 nm in thickness) with orthorhombic Mo2C nanoparticles (≈2 nm in diameter), a high surface area of ≈426 m2 g-1, and open mesopores (≈6.9 nm in size). Experiments and calculations corroborate the hierarchically mesoporous Mo2C/C can enhance hydrophilicity for supplying sufficient O2, accelerate oxygen reduction kinetics by highly-active Mo2C and N-doped carbon sites, and facilitate O2 diffusion kinetics over hierarchically mesopores. Therefore, Meso-Mo2C/C-14 outputs a high half-wave potential (0.88 V vs RHE) with a low Tafel slope (51 mV dec-1) for oxygen reduction. More significantly, the Zn-air battery delivers an ultrahigh power density (272 mW cm-2), and an unprecedented 100 h stability at a high-current-density condition (100 mA cm-2), which is one of the best performances.

3.
Small ; 19(28): e2301203, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37010007

RESUMEN

Hard carbons (HCs) with high sloping capacity are considered as the leading candidate anode for sodium-ion batteries (SIBs); nevertheless, achieving basically complete slope-dominated behavior with high rate capability is still a big challenge. Herein, the synthesis of mesoporous carbon nanospheres with highly disordered graphitic domains and MoC nanodots modification via a surface stretching strategy is reported. The MoOx surface coordination layer inhibits the graphitization process at high temperature, thus creating short and wide graphite domains. Meanwhile, the in situ formed MoC nanodots can greatly promote the conductivity of highly disordered carbon. Consequently, MoC@MCNs exhibit an outstanding rate capacity (125 mAh g-1 at 50 A g-1 ). The "adsorption-filling" mechanism combined with excellent kinetics is also studied based on the short-range graphitic domains to reveal the enhanced slope-dominated capacity. The insight in this work encourages the design of HC anodes with dominated slope capacity toward high-performance SIBs.

4.
Am J Pathol ; 192(10): 1433-1447, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35948079

RESUMEN

Costimulatory molecules are an indispensable signal for activating immune cells. However, the features of many costimulatory molecule genes (CMGs) in lung adenocarcinoma (LUAD) are poorly understood. This study systematically explored expression patterns of CMGs in the tumor immune microenvironment (TIME) status of patients with LUAD. Their expression profiles were downloaded from The Cancer Genome Atlas and the Gene Expression Omnibus databases. Two robust TIME subtypes ("hot" and "cold") were classified by K-means clustering and estimation of stromal and immune cells in malignant tumor tissues using expression data. The "hot" subtype presented higher infiltration in activated immune cells and enrichments in the immune cell receptor signaling pathway and adaptive immune response. Three CMGs (CD80, LTB, and TNFSF8) were screened as final diagnostic markers by means of Least Absolute Shrinkage Selection Operator and Support Vector Machine-Recursive Feature Elimination algorithms. Accordingly, the diagnostic nomogram for predicting individualized TIME status showed satisfactory diagnostic accuracy in The Cancer Genome Atlas training cohort as well as GSE31210 and GSE180347 validation cohorts. Immunohistochemistry staining of 16 specimens revealed an apparently positive correlation between the expression of CMG biomarkers and pathologic response to immunotherapy. Thus, this diagnostic nomogram provided individualized predictions in TIME status of LUAD patients with good predictive accuracy, which could serve as a potential tool for identifying ideal candidates for immunotherapy.


Asunto(s)
Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Adenocarcinoma del Pulmón/diagnóstico , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/metabolismo , Algoritmos , Biología Computacional , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Aprendizaje Automático , Pronóstico , Microambiente Tumoral/genética
5.
Acta Biochim Biophys Sin (Shanghai) ; 55(5): 736-748, 2023 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-37171184

RESUMEN

Nine polyglutamine (polyQ) proteins have already been identified that are considered to be associated with the pathologies of neurodegenerative disorders called polyQ diseases, but whether these polyQ proteins mutually interact and synergize in proteinopathies remains to be elucidated. In this study, 4 polyQ-containing proteins, androgen receptor (AR), ataxin-7 (Atx7), huntingtin (Htt) and ataxin-3 (Atx3), are used as model molecules to investigate their heterologous coaggregation and consequent impact on cellular proteostasis. Our data indicate that the N-terminal fragment of polyQ-expanded (PQE) Atx7 or Htt can coaggregate with and sequester AR and Atx3 into insoluble aggregates or inclusions through their respective polyQ tracts. In vitro coprecipitation and NMR titration experiments suggest that this specific coaggregation depends on polyQ lengths and is probably mediated by polyQ-tract interactions. Luciferase reporter assay shows that these coaggregation and sequestration effects can deplete the cellular availability of AR and consequently impair its transactivation function. This study provides valid evidence supporting the viewpoint that coaggregation of polyQ proteins is mediated by polyQ-tract interactions and benefits our understanding of the molecular mechanism underlying the accumulation of different polyQ proteins in inclusions and their copathological causes of polyQ diseases.


Asunto(s)
Enfermedades Neurodegenerativas , Proteostasis , Humanos , Péptidos/química , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Ataxina-3/genética , Ataxina-3/metabolismo
6.
J Am Chem Soc ; 144(5): 2208-2217, 2022 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-35099956

RESUMEN

Iridium (Ir)-based electrocatalysts are widely explored as benchmarks for acidic oxygen evolution reactions (OERs). However, further enhancing their catalytic activity remains challenging due to the difficulty in identifying active species and unfavorable architectures. In this work, we synthesized ultrathin Ir-IrOx/C nanosheets with ordered interlayer space for enhanced OER by a nanoconfined self-assembly strategy, employing block copolymer formed stable end-merged lamellar micelles. The interlayer distance of the prepared Ir-IrOx/C nanosheets was well controlled at ∼20 nm and Ir-IrOx nanoparticles (∼2 nm) were uniformly distributed within the nanosheets. Importantly, the fabricated Ir-IrOx/C electrocatalysts display one of the lowest overpotential (η) of 198 mV at 10 mA cm-2geo during OER in an acid medium, benefiting from their features of mixed-valence states, rich electrophilic oxygen species (O(II-δ)-), and favorable mesostructured architectures. Both experimental and computational results reveal that the mixed valence and O(II-δ)- moieties of the 2D mesoporous Ir-IrOx/C catalysts with a shortened Ir-O(II-δ)- bond (1.91 Å) is the key active species for the enhancement of OER by balancing the adsorption free energy of oxygen-containing intermediates. This strategy thus opens an avenue for designing high performance 2D ordered mesoporous electrocatalysts through a nanoconfined self-assembly strategy for water oxidation and beyond.

7.
Small ; 18(37): e2202238, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35973948

RESUMEN

The electrocatalytic carbon dioxide reduction reaction (CO2 RR) to value-added chemical products is an effective strategy for both greenhouse effect mitigation and high-density energy storage. However, controllable manipulation of the oxidation state and porous structure of Cu-carbon based catalysts to achieve high selectivity and current density for a particular product remains very challenging. Herein, a strategy derived from Cu-based metal-organic frameworks (MOFs) for the synthesis of controllable oxidation states and porous structure of Cu-carbon (Cu-pC, Cu2 O-pC, and Cu2 O/Cu-pC) is demonstrated. By regulating oxygen partial pressure during the annealing process, the valence state of the Cu and mesoporous structures of surrounding carbon are changed, leads to the different selectivity of products. Cu2 O/CuO-pC with the higher oxidation state exhibits FEC2H4 of 65.12% and a partial current density of -578 mA cm-2 , while the Cu2 O-pC shows the FECH4 over 55% and a partial current density exceeding -438 mA cm-2 . Experimental and theoretical studies indicate that porous carbon-coated Cu2 O structures favor the CH4 pathway and inhibit the hydrogen evolution reaction. This work provides an effective strategy for exploring the influence of the various valence states of Cu and mesoporous carbon structures on the selectivity of CH4 and C2 H4 products in CO2 RR.

8.
Nano Lett ; 21(14): 6071-6079, 2021 07 28.
Artículo en Inglés | MEDLINE | ID: mdl-34269590

RESUMEN

Streamlined architectures with a low fluid-resistance coefficient have been receiving great attention in various fields. However, it is still a great challenge to synthesize streamlined architecture with tunable surface curvature at the nanoscale. Herein, we report a facile interfacial dynamic migration strategy for the synthesis of streamlined mesoporous nanotadpoles with varied architectures. These tadpole-like nanoparticles possess a big streamlined head and a slender tail, which exhibit large inner cavities (75-170 nm), high surface areas (424-488 m2 g-1), and uniform mesopore sizes (2.4-3.2 nm). The head curvature of the streamlined mesoporous nanoparticles can be well-tuned from ∼2.96 × 10-2 to ∼5.56 × 10-2 nm-1, and the tail length can also be regulated from ∼30 to ∼650 nm. By selectively loading the Fe3O4 catalyst in the cavity of the streamlined silica nanotadpoles, the H2O2-driven mesoporous nanomotors were designed. The mesoporous nanomotors with optimized structural parameters exhibit outstanding directionality and a diffusion coefficient of 8.15 µm2 s-1.


Asunto(s)
Nanopartículas , Dióxido de Silicio , Catálisis , Peróxido de Hidrógeno , Porosidad
9.
J Am Chem Soc ; 143(35): 14097-14105, 2021 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-34379403

RESUMEN

Surface redox pseudocapacitance, which enables short charging times and high power delivery, is very attractive in a wide range of sites. To achieve maximized specific capacity, nanostructuring of active materials with high surface area is indispensable. However, one key limitation for capacitive materials is their low volumetric capacity due to the low tap density of nanomaterials. Here, we present a promising mesoscale TiO2 structure with precisely controlled mesoporous frameworks as a high-density pseudocapacitive model system. The dense-packed mesoscopic TiO2 in micrometer size offers a high accessible surface area (124 m2 g-1) and radially aligned mesopore channels, but high tap density (1.7 g cm-3) that is much higher than TiO2 nanoparticles (0.47 g cm-3). As a pseudocapacitive sodium-ion storage anode, the precisely designed mesoscopic TiO2 model achieved maximized gravimetric capacity (240 mAh g-1) and volumetric capacity (350 mAh cm-3) at 0.025 A g-1. Such a designed pseudocapacitive mesostructure further realized a commercially comparable areal capacity (2.1 mAh cm-2) at a high mass loading of 9.47 mg cm-2. This mesostructured electrode that enables fast sodiation in dense nanostructures has implications for high-power applications, fast-charging devices, and pseudocapacitive electrode design.

10.
Ann Surg Oncol ; 28(6): 3025-3033, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33073346

RESUMEN

BACKGROUND: The impact of the number of examined lymph nodes (ELNs) on stage correction and prognostication in patients with esophageal squamous cell carcinoma (ESCC) who underwent right transthoracic esophagectomy is still unclear. METHODS: Patients with ESCC who underwent right transthoracic esophagectomy at Sun Yat-sen University Cancer Center between January 1997 and December 2013 were retrospectively enrolled. The Cox proportional hazards regression model was used to determine the effect of ELN count on overall survival. The impact of ELN count on stage correction was evaluated using the hypergeometric distribution and Bayes theorem and ß-binomial distribution estimation, respectively. The threshold of ELNs was determined using the LOWESS smoother and piecewise linear regression. RESULTS: Among the 875 included patients, greater ELNs were associated with a higher rate of nodal metastasis. Significant association between staging bias and the number of ELNs is only observed through the Bayes method. The ELN count did not impact 90-day mortality but significantly impacted long-term survival (adjusted hazard ratio [aHR] 0.986), especially in those patients with node-negative disease (aHR 0.972). In patients with node-negative disease, cut-point analysis showed a threshold ELN count of 21. CONCLUSIONS: A greater number of ELNs is associated with more accurate node staging and better long-term survival in resected ESCC patients. We recommended harvesting at least 21 LNs to acquire accurate staging and long-term survival information for patients with declared node-negative disease using the right thoracic approach.


Asunto(s)
Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Neoplasias de Cabeza y Cuello , Teorema de Bayes , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/cirugía , Carcinoma de Células Escamosas de Esófago/cirugía , Esofagectomía , Humanos , Escisión del Ganglio Linfático , Ganglios Linfáticos/patología , Ganglios Linfáticos/cirugía , Metástasis Linfática , Estadificación de Neoplasias , Estudios Retrospectivos , Tasa de Supervivencia
11.
Biochem J ; 477(21): 4295-4312, 2020 11 13.
Artículo en Inglés | MEDLINE | ID: mdl-33094816

RESUMEN

Ubiquitin-specific protease 19 (USP19) is a member of the deubiquitinating (DUB) enzymes that catalyze removing the ubiquitin signals from target proteins. Our previous research has demonstrated that USP19 up-regulates the protein level and aggregation of polyQ-expanded huntingtin through the involvement of heat shock protein 90 (HSP90). Here, we present solution structures of the CS1, CS2 and UbL domains of USP19 and structural insights into their domain interactions. We found that the tandem CS domains fold back to interact with the C-terminal USP domain (USPD) intra-molecularly that leads to inhibition of the catalytic core of USP19, especially CS1 interacts with the embedded UbL domain and CS2 does with the CH2 catalytic core. Moreover, CS2 specifically interacts with the NBD domain of HSP90, which can activate the DUB enzyme. A mechanism of auto-inhibition of USP19 and activation by HSP90 is proposed, on which USP19 modulates the protein level of polyQ-expanded huntingtin in cells. This study provides structural and mechanistic insights into the modulation of protein level and aggregation by USP19 with the assistance of HSP90.


Asunto(s)
Endopeptidasas/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Enzimas Desubicuitinizantes/metabolismo , Humanos , Proteína Huntingtina/metabolismo , Péptidos/metabolismo , Ubiquitina/metabolismo , Ubiquitinación
12.
BMC Pediatr ; 21(1): 297, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-34210262

RESUMEN

BACKGROUND: Infantile malignant osteopetrosis (IMO) is a rare autosomal recessive disease characterized by a higher bone density in bone marrow caused by the dysfunction of bone resorption. Clinically, IMO can be diagnosed with medical examination, bone mineral density test and whole genome sequencing. CASE PRESENTATION: We present the case of a 4-month-old male infant with abnormal skull development, hypocalcemia and premature closure of the cranial sutures. Due to the hyper bone density showed by his radiographic examination, which are characteristic patterns of IMO, we speculated that he might be an IMO patient. In order to confirm this diagnosis, a high-precision whole exome sequencing of the infant and his parents was performed. The analysis of high-precision whole exome sequencing results lead to the identification of two novel heterozygous mutations c.504-1G > C (a splicing site mutation) and c.1371delC (p.G458Afs*70, a frameshift mutation) in gene TCIRG1 derived from his parents. Therefore, we propose that there is a close association between these two mutations and the onset of IMO. CONCLUSIONS: To date, these two novel mutations in gene TCIRG1 have not been reported in the reference gene database of Chinese population. These variants have likewise not been reported outside of China in the Genome Aggregation Database (gnomAD). Our case suggests that the use of whole exome sequencing to detect these two mutations will improve the identification and early diagnosis of IMO, and more specifically, the identification of homozygous individuals with TCIRG1 gene mutation. We propose that these mutations in gene TCIRG1 could be a novel therapeutic target for the IMO in the future.


Asunto(s)
Osteopetrosis , ATPasas de Translocación de Protón Vacuolares , China , Homocigoto , Humanos , Lactante , Masculino , Mutación , Osteopetrosis/diagnóstico por imagen , Osteopetrosis/genética , ATPasas de Translocación de Protón Vacuolares/genética , ATPasas de Translocación de Protón Vacuolares/metabolismo
13.
J Clin Lab Anal ; 35(9): e23895, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34233042

RESUMEN

INTRODUCTION: Serum neuron-specific enolase (NSE) is an important tumor marker for small cell lung cancer and neuroblastoma. However, the test of serum NSE compromised by specimen hemolysis is presented as a falsely higher result, which seriously disturbs clinical decision. This study aimed to establish a solution integrated with laboratory information system to clear the bias from hemolysis on serum NSE test. METHODS: The reference range of serum hemolysis index (HI) was first established, and specimen hemolysis rate was compared between HI test and visual observation. NSE concentration in serum pool with normal HI was spiked with serial diluted lysates from red blood cells to deduce individual corrective equation. The agreement between individual corrective equation and original NSE test was assayed by Bland and Altman plots. RESULTS: The high HI existed in 32.6% of specimens from patients. The NSE median of hemolyzed specimens was significant higher than the baseline (p = 0.038), while the corrected NSE median had no difference compared with the baseline (p = 0.757). The mean difference of corrected NSE and initial NSE was 1.92%, the SD of difference was 5.23%, and furthermore, the difference was independent of tendency of HI (Spearman r = -0.069, p = 0.640). The 95% confidence interval of mean difference (from -8.33% to 12.17%) was less than the acceptable bias range (±20%). CONCLUSION: The agreement between individual correction equation and NSE assay was satisfied. Our automated processing algorithm for serum NSE could provide efficient management of posttest data and correct positive bias from specimen hemolysis.


Asunto(s)
Algoritmos , Biomarcadores de Tumor/sangre , Pruebas Hematológicas/normas , Hemólisis , Neoplasias/patología , Fosfopiruvato Hidratasa/sangre , Manejo de Especímenes/normas , Automatización , Humanos , Neoplasias/sangre , Neoplasias/enzimología
14.
J Cell Biochem ; 120(2): 2439-2453, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30324748

RESUMEN

As a unique subtype of esophageal cancer, synchronous multiple primary esophageal squamous cell carcinomas (ESCCs) mostly occur in Asian patients with alcohol and/or tobacco abuse, or with a family history of cancer. Multiple ESCCs are associated with poor clinical outcomes. Growing evidence has addressed that long noncoding RNAs (lncRNAs) are involved in the carcinogenesis of various malignancies. We compared the lncRNA and messenger RNA (mRNA) profiles between solitary and multiple ESCC tissues through microarray analysis, aiming at studying their different mechanisms in tumor development. As a result, in multiple ESCCs, a total of 5257 lncRNAs and 3371 mRNAs were consistently differentially expressed compared with solitary ESCC, including 2986 upregulated and 2271 downregulated lncRNAs, and 2313 upregulated, and 1058 downregulated mRNAs. We validated the results in four differentially expressed lncRNAs using quantitative real-time polymerase chain reaction. There were 38 and 20 pathways significantly related to up- and downregulated transcripts. The pathways associated with mostly enriched up- and downregulated mRNAs were hsa01200 (carbon metabolism) and hsa05221 (acute myeloid leukemia- homo sapiens [human]). Gene ontology analysis suggested that upregulated and downregulated mRNAs were mainly enriched in bounding membrane of organelle involved in the cellular component and positive regulation of transport involved in the biological process. Further analysis identified 189 differentially expressed paired antisense lncRNAs and relative sense mRNA, as well as 2134 differentially expressed long intergenic noncoding RNAs and their adjacent mRNA pairs. In conclusion, the aberrantly expressed lncRNAs might play a role in the carcinogenesis of multiple ESCCs and could be candidates as diagnostic biomarkers and therapeutic targets.

15.
FASEB J ; 32(6): 2923-2933, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29401586

RESUMEN

The components of ubiquitin (Ub)-proteasome system, such as Ub, Ub adaptors, or proteasome subunits, are commonly accumulated with the aggregated proteins in inclusions, but how protein aggregates sequester Ub-related proteins remains elusive. Using N-terminal huntingtin (Htt-N552) and ataxin (Atx)-3 as model proteins, we investigated the molecular mechanism underlying sequestration of Ub adaptors by polyQ-expanded proteins. We found that polyQ-expanded Htt-N552 and Atx-3 sequester endogenous Ub adaptors, human RAD23 homolog B (hHR23B) and ubiquilin (UBQLN)-2, into inclusions. This sequestration effect is dependent on the UBA domains of Ub adaptors and the conjugated Ub of the aggregated proteins. Moreover, polyQ-expanded Htt-N552 and Atx-3 reduce the protein level of xeroderma pigmentosum group C (XPC) by sequestration of hHR23B, suggesting that this process may cut down the available quantity of hHR23B and thus affect its normal function in stabilizing XPC. Our findings demonstrate that polyQ-expanded proteins sequester Ub adaptors or other Ub-related proteins into aggregates or inclusions through ubiquitination of the pathogenic proteins. This study may also provide a common mechanism for the formation of Ub-positive inclusions in cells.-Yang, H., Yue, H.-W., He, W.-T., Hong, J.-Y., Jiang, L.-L., Hu, H.-Y. PolyQ-expanded huntingtin and ataxin-3 sequester ubiquitin adaptors hHR23B and UBQLN2 into aggregates via conjugated ubiquitin.


Asunto(s)
Ataxina-3/metabolismo , Proteínas de Ciclo Celular/metabolismo , Enzimas Reparadoras del ADN/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteína Huntingtina/metabolismo , Péptidos/metabolismo , Proteínas Represoras/metabolismo , Ubiquitinas/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Ataxina-3/genética , Proteínas Relacionadas con la Autofagia , Proteínas de Ciclo Celular/genética , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Células HEK293 , Humanos , Proteína Huntingtina/genética , Péptidos/genética , Dominios Proteicos , Estabilidad Proteica , Proteínas Represoras/genética , Ubiquitinas/genética
16.
BMC Neurol ; 19(1): 3, 2019 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-30606133

RESUMEN

BACKGROUND: Several neuroimaging studies have reported neurophysiological alterations in patients with benign childhood epilepsy with centrotemporal spikes (BCECTS). However, reported outcomes have been inconsistent, and the progression of these changes in the brain remains unresolved. Moreover, background electroencephalography (EEG) in cases of BCECTS has not been performed often. METHODS: We investigated background EEG activity changes after six months of oxcarbazepine treatment to better understand the neurophysiological alterations and progression that occur in BCECTS. In 18 children with BCECTS, non-parametric statistical analyses using standardized low resolution brain electromagnetic tomography (sLORETA) were performed to compare the current density distribution of four frequency bands (delta, theta, alpha, and beta) between untreated and treated conditions. RESULTS: Background EEG activity for the delta frequency band was significantly decreased in the fronto-temporal and limbic regions of the left hemisphere after oxcarbazepine treatment (threshold log-F-ratio = ±2.729, P < 0.01). The maximum current density difference was found in the parahippocampal gyrus of the left limbic lobe (Montreal Neurological Institute coordinate [x, y, z = 25, - 20, - 10], Brodmann area 28) (log-F-ratio = 3.081, P < 0.01). CONCLUSIONS: Our results indicate the involvement of the fronto-temporal and limbic cortices in BCECTS, and limbic lobe involvement, including the parahippocampal gyrus, was noted. In addition to evidence of the involvement of the fronto-temporal and limbic cortices in BCECTS, this study also found that an antiepileptic drug could reduce the delta frequency activity of the background EEG in these regions.


Asunto(s)
Anticonvulsivantes/uso terapéutico , Epilepsia Rolándica , Neuroimagen/métodos , Oxcarbazepina/uso terapéutico , Tomografía/métodos , Encéfalo/diagnóstico por imagen , Niño , Estudios de Cohortes , Electroencefalografía , Epilepsia Rolándica/diagnóstico por imagen , Epilepsia Rolándica/tratamiento farmacológico , Epilepsia Rolándica/fisiopatología , Humanos
17.
Plant Cell Rep ; 38(3): 311-319, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30552452

RESUMEN

KEY MESSAGE: CLV3p-mediated phosphorylation of MPK3 and MPK6 occurs via CLV1 and BAM1 receptors to regulate the maintenance of SAM development. The CLAVATA peptide-receptor (CLV3p-CLV1) pathway modulates a homeodomain master regulator WUSCHEL (WUS) transcription factor in the shoot apical meristem (SAM) with poorly defined signaling mechanisms. Here, we report that mitogen-activated protein kinases (MAPKs, also known as MPKs in plants) act in an intracellular signaling cascade to play an important role in the maintenance of SAM development. Interestingly, the application of exogenous CLV3p triggers rapid signaling in the SAM via dynamic activation of MPK3 and MPK6, which are positively regulated by both CLV1 and BARELY ANY MERISTEM 1 (BAM1) receptors. Surprisingly, the timing of MAPK activation is tightly correlated with the transcriptional repression of WUS expression in the SAM, indicating a fast CLV3p-CLV1/BAM1 signaling event. Furthermore, conditional mpk3,6 double mutants exhibited CLV3p insensitivity in stem cell maintenance manifested by the persistent SAM growth in the presence of exogenous CLV3p signals, as well as elevated WUS expression and repressed WUS-specific target genes. Taken together, these results suggest that MPK3 and MPK6 activated by CLV3p signals through mainly CLV1 and BAM1 receptors are key regulators controlling stem cell homeostasis in the SAM.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Brotes de la Planta/metabolismo , Células Madre/metabolismo , Proteínas de Arabidopsis/genética , Homeostasis/fisiología , Meristema/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Serina-Treonina Quinasas/metabolismo
18.
Neurol Sci ; 40(5): 993-1000, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30756246

RESUMEN

Localizing the source of epileptiform discharges in generalized epilepsy has been controversial for the past few decades. Recent neuroimaging studies have shown that epileptiform discharges in generalized epilepsy can be localized to a particular region. Childhood absence epilepsy (CAE) is the most common generalized epilepsy in childhood and is considered the prototype of idiopathic generalized epilepsy (IGE). To better understand electrophysiological changes and their development in CAE, we investigated the origin of epileptiform discharges. We performed distributed source localization with standardized, low-resolution, brain electromagnetic tomography (sLORETA). In 16 children with CAE, sLORETA images corresponding to the midpoint of the ascending phase and the negative peak of the spike were obtained from a total of 242 EEG epochs (121 epochs at each timepoint). Maximal current source density (CSD) was mostly located in the frontal lobe (69.4%). At the gyral level, maximal CSD was most commonly in the superior frontal gyrus (39.3%) followed by the middle frontal gyrus (14.0%) and medial frontal gyrus (8.7%). At the hemisphere level, maximal CSD was dominant in the right cerebral hemisphere (63.6%). These results were consistent at the midpoint of the ascending phase and the negative peak of the spike. Our results demonstrated that the major source of epileptiform discharges in CAE was the frontal lobe. These results suggest that the frontal lobe is involved in generating CAE. This finding is consistent with recent studies that have suggested selective cortical involvement, especially in the frontal regions, in IGE.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/fisiopatología , Electroencefalografía/métodos , Epilepsia Tipo Ausencia/diagnóstico , Epilepsia Tipo Ausencia/fisiopatología , Niño , Femenino , Humanos , Masculino , Modelos Teóricos , Procesamiento de Señales Asistido por Computador
19.
Angew Chem Int Ed Engl ; 57(26): 7649-7653, 2018 06 25.
Artículo en Inglés | MEDLINE | ID: mdl-29696766

RESUMEN

Water electrolysis is a promising source of hydrogen; however, technological challenges remain. Intensive efforts have focused on developing highly efficient and earth-abundant electrocatalysts for water splitting. An effective strategy is proposed, using a bifunctional tubular cobalt perselenide nanosheet electrode, in which the sluggish oxygen evolution reaction is substituted with anodic hydrazine oxidation so as to assist energy-efficient hydrogen production. Specifically, this electrode produces a current density of 10 mA cm-2 at -84 mV for hydrogen evolution and -17 mV for hydrazine oxidation in 1.0 m KOH and 0.5 m hydrazine electrolyte. An ultralow cell voltage of only 164 mV is required to generate a current density of 10 mA cm-2 for 14 hours of stable water electrolysis.

20.
Biotechnol Bioeng ; 114(10): 2360-2370, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28542705

RESUMEN

The practical application of microfluidic liver models for in vitro drug testing is partly hampered by their reliance on human primary hepatocytes, which are limited in number and have batch-to-batch variation. Human stem cell-derived hepatocytes offer an attractive alternative cell source, although their 3D differentiation and maturation in a microfluidic platform have not yet been demonstrated. We develop a pump-free microfluidic 3D perfusion platform to achieve long-term and efficient differentiation of human liver progenitor cells into hepatocyte-like cells (HLCs). The device contains a micropillar array to immobilize cells three-dimensionally in a central cell culture compartment flanked by two side perfusion channels. Constant pump-free medium perfusion is accomplished by controlling the differential heights of horizontally orientated inlet and outlet media reservoirs. Computational fluid dynamic simulation is used to estimate the hydrostatic pressure heads required to achieve different perfusion flow rates, which are experimentally validated by micro-particle image velocimetry, as well as viability and functional assessments in a primary rat hepatocyte model. We perform on-chip differentiation of HepaRG, a human bipotent progenitor cell, and discover that 3D microperfusion greatly enhances the hepatocyte differentiation efficiency over static 2D and 3D cultures. However, HepaRG progenitor cells are highly sensitive to the time-point at which microperfusion is applied. Isolated HepaRG cells that are primed as static 3D spheroids before being subjected to microperfusion yield a significantly higher proportion of HLCs (92%) than direct microperfusion of isolated HepaRG cells (62%). This platform potentially offers a simple and efficient means to develop highly functional microfluidic liver models incorporating human stem cell-derived HLCs. Biotechnol. Bioeng. 2017;114: 2360-2370. © 2017 Wiley Periodicals, Inc.


Asunto(s)
Técnicas de Cultivo Celular por Lotes/instrumentación , Diferenciación Celular/fisiología , Hepatocitos/fisiología , Dispositivos Laboratorio en un Chip , Técnicas de Cultivo de Órganos/instrumentación , Perfusión/instrumentación , Células Madre/fisiología , Técnicas de Cultivo Celular por Lotes/métodos , Técnicas de Cultivo de Célula/instrumentación , Técnicas de Cultivo de Célula/métodos , Proliferación Celular/fisiología , Células Cultivadas , Diseño de Equipo , Análisis de Falla de Equipo , Hepatocitos/citología , Humanos , Técnicas de Cultivo de Órganos/métodos , Células Madre/citología , Ingeniería de Tejidos/instrumentación , Ingeniería de Tejidos/métodos
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