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1.
Endocr Pract ; 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38729572

RESUMEN

OBJECTIVE: Diabetic foot ulcers (DFUs) are a leading cause of morbidity and mortality, which disproportionately impacts underserved populations. This study aimed to provide data regarding the rates and outcomes of amputation in patients admitted with DFU in our health system, which cares for an ethnically diverse and underserved population. METHODS: This retrospective study examined the electronic medical records of adult patients hospitalized with DFU at 3 hospitals in our health system between June 1, 2016, and May 31, 2021. RESULTS: Among 650 patients admitted with DFU, 88% self-identified as non-White race. Male sex (odds ratio [OR], 0.62), low body mass index (OR, 0.98), and history of smoking (OR, 1.45) were significantly associated with amputation during the study period. A higher erythrocyte sedimentation rate (OR, 1.01), C-reactive protein level (OR, 1.05), and white blood cell count (OR, 1.11) and low albumin level (OR, 0.41) were found to be significantly associated with amputation versus no amputation during admission. The amputation risk during the index admission for DFU was 44%. CONCLUSION: Our study identified a high DFU-related amputation risk (44%) among adult patients who were mostly Black and/or Hispanic. The significant risk factors associated with DFU amputation included male sex, low body mass index, smoking, and high levels inflammation or low levels of albumin during admission. Many of these patients required multidisciplinary care and intravenous antibiotic therapy, necessitating a longer length of stay and high readmission rate.

2.
J Environ Manage ; 329: 117089, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36565499

RESUMEN

Efficient electrode materials are essential to convert salinity gradient energy into oxidative degradation energy and electrical energy by reverse electrodialysis reactor (REDR). In this context, comparative experiments of REDR using different anodes (Ti/IrO2-RuO2, Ti/PbO2 and Ti/Ti4O7) were conducted. The effects of output current and electrode rinse solution (ERS) flowrate on mineralization efficiency and energy output were discussed. Results demonstrated that the COD removal rate(ηCOD) rose almost linearly with output current and ERS flowrate when using Ti/Ti4O7 anode, but excessive operating conditions caused a slow increase or even decrease of ηCOD when using Ti/IrO2-RuO2 or Ti/PbO2 anodes. The order of electrode system potential loss (Eele) for the three anodes was Ti/Ti4O7> Ti/PbO2> Ti/IrO2-RuO2. High Eele was beneficial to ηCOD but had a negative effect on the net output power (Pnet) of REDR. Regardless of the applied anodes, increasing the current and decreasing the ERS flowrate was detrimental to Pnet due to higher Eele. Based on these findings, four energy efficiency parameters were defined to evaluate energy recovery from multiple perspectives by linking energy output with mineralization capacity. They were electrode efficiency (ηele), energy efficiency (EE), general current efficiency (GCE) and energy consumption (EC), respectively. Results showed that REDR with Ti/Ti4O7 anodes and suitable operating conditions achieved the optimal energy indicators and mineralization efficiency, which provided an efficient and economical option for wastewater treatment and energy recovery.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Fenol , Fenoles , Oxidación-Reducción , Electrodos , Titanio
3.
Chemistry ; 28(51): e202201407, 2022 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-35789002

RESUMEN

The efficiency of photocatalytic overall water splitting reactions is usually limited by the high energy barrier and complex multiple electron-transfer processes of the oxygen evolution reaction (OER). Although bismuth vanadate (BiVO4 ) as the photocatalyst has been developed for enhancing the kinetics of the water oxidation reaction, it still suffers from challenges of fast recombination of photogenerated electron-hole pairs and poor photocatalytic activity. Herein, six MII -CoIII Prussian blue analogues (PBAs) (M=Mn, Fe, Co, Ni, Cu and Zn) cocatalysts are synthesized and deposited on the surface of BiVO4 for boosting the surface catalytic efficiency and enhancing photogenerated carries separation efficiency of BiVO4 . Six MII -CoIII PBAs@BiVO4 photocatalysts all demonstrate increased photocatalytic water oxidation performance compared to that of BiVO4 alone. Among them, the Co-Co PBA@BiVO4 photocatalyst is employed as a representative research object and is thoroughly characterized by electrochemistry, electronic microscope as well as multiple spectroscopic analyses. Notably, BiVO4 coupling with Co-Co PBA cocatalyst could capture more photons than that of pure BiVO4 , facilitating the transfer of photogenerated charge carriers between BiVO4 and Co-Co PBA as well as the surface catalytic efficiency of BiVO4 . Overall, this work would promote the synthesis strategy development for exploring new types of composite photocatalysts for water oxidation.

4.
Environ Res ; 214(Pt 4): 114064, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35977587

RESUMEN

In this paper, the synthetic methyl orange (MO) dyeing wastewater treated by a reverse electrodialysis reactor (REDR) with 40 member pairs was investigated first. The boron-doped diamond (BDD) and carbon felt were adopted as an anode and a cathode in the REDR. The influences of operation parameters on the chemical oxygen demand (COD) removal efficiency were detected and explored. Then, a mathematical model of organic mineralizing was developed for the REDR to predict the variation of COD removal efficiency with treating time under the different operation conditions. Finally, the energy consumption of the wastewater treated by the REDR was analyzed. The results showed that raising the working fluid flowing velocity and electrode rinse solution flowrate improved the COD removal efficiency and instantaneous current efficiency (ICE), and reduced the total energy consumption (TEC) of the REDR. Raising the initial MO concentration could significantly reduce the TEC despite the COD removal efficiency being near. Since the main energy consumed by the REDR was salinity gradient energy (SGE) from waste heat conversion or the natural environment, the energy cost of REDR treating wastewater has been reduced significantly.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Compuestos Azo , Análisis de la Demanda Biológica de Oxígeno , Colorantes , Oxidación-Reducción , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/análisis
5.
Sensors (Basel) ; 22(20)2022 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-36298185

RESUMEN

Battery state of health (SOH) estimating is essential for the safety and preservation of electric vehicles. The degradation mechanism of batteries under different aging conditions has attracted considerable attention in SOH prediction. In this article, the discharge voltage curve early in the cycle is considered to be strongly characteristic during cell aging. Therefore, the battery aging state can be quantitatively characterized by an incremental capacity analysis (ICA) of the voltage distribution. Due to the interference of vibration noise of the test platform, the discrete wavelet transform (DWT) methods are accustomed to soften the premier incremental capacity curves in different hierarchical decompositions. By analyzing the battery aging mechanism, the peak of the curve and its corresponding voltage are used in the characterization of capacity decay by grey relation analysis (GRA) and to optimize the input of the deep learning model, and finally, the double-layer long short-term memory network (LSTM) model is used to train the data. The results demonstrate that the proposed model can predict the SOH of a single battery cycle using only small batch data and the relative error is less than 2%. Further, by freezing the LSTM layer for transfer learning, it can be used for battery health estimation in different loading modes. The results of training and verification show that this method has high accuracy and reliability in SOH estimation.


Asunto(s)
Suministros de Energía Eléctrica , Memoria a Corto Plazo , Reproducibilidad de los Resultados , Análisis de Ondículas , Aprendizaje Automático
6.
J Am Chem Soc ; 140(4): 1508-1513, 2018 01 31.
Artículo en Inglés | MEDLINE | ID: mdl-29303578

RESUMEN

Cu/Ir dual catalysis has been developed for the stereodivergent α-allylation of aldimine esters. The method enables the preparation of a series of nonproteinogenic α-amino acids (α-AAs) bearing two contiguous stereogenic centers in high yield with excellent stereoselectivity. All four product stereoisomers could be obtained from the same set of starting materials via pairwise combination of two chiral catalysts. Notably, one-pot protocol could be successfully applied for the preparation of the bimetallic Cu/Ir complexes to simplify the manipulation of Cu/Ir dual catalysis. This method could be further utilized for the construction of the key intermediate of a bioactive pyrrolidine derivative and the concise synthesis of a plant growth regulator (2S,3S)-2-amino-3-cyclopropylbutanoic acid.


Asunto(s)
Aminoácidos/síntesis química , Cobre/química , Iridio/química , Aminoácidos/química , Catálisis , Estructura Molecular , Estereoisomerismo
7.
Angew Chem Int Ed Engl ; 56(40): 12312-12316, 2017 09 25.
Artículo en Inglés | MEDLINE | ID: mdl-28741842

RESUMEN

An unprecedented enantioselective allylic alkylation of readily available aldimine esters has been developed, and is catalyzed by a synergistic Cu/Pd catalyst system. This strategy provides facile access to nonproteinogenic α,α-disubstituted α-amino acids in high yield with excellent enantioselectivity. The more challenging double allylic alkylation of glycinate-derived imine esters was also realized. Furthermore, this methodology was applied for the construction of the key intermediate of PLG peptidomimetics.


Asunto(s)
Aminoácidos/química , Cobre/química , Iminas/química , Paladio/química , Alquilación , Catálisis , Ésteres , Espectroscopía de Resonancia Magnética , Peptidomiméticos/química , Estereoisomerismo
8.
J Cell Mol Med ; 20(12): 2249-2258, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27489081

RESUMEN

The liver X receptor (LXR) is a cholesterol-sensing nuclear receptor that has an established function in lipid metabolism; however, its role in inflammation is elusive. In this study, we showed that the LXR agonist GW3965 exhibited potent anti-inflammatory activity by suppressing the firm adhesion of monocytes to endothelial cells. To further address the mechanisms underlying the inhibition of inflammatory cell infiltration, we evaluated the effects of LXR agonist on interleukin-8 (IL-8) secretion and nuclear factor-kappa B (NF-κB) activation in human umbilical vein endothelial cells (HUVECs). The LXR agonist significantly inhibited lysophosphatidylcholine (LPC)-induced IL-8 production in a dose-dependent manner without appreciable cytotoxicity. Western blotting and the NF-κB transcription activity assay showed that the LXR agonist inhibited p65 binding to the IL-8 promoter in LPC-stimulated HUVECs. Interestingly, knockdown of the indispensable small ubiquitin-like modifier (SUMO) ligases Ubc9 and Histone deacetylase 4 (HDAC4) reversed the increase in IL-8 induced by LPC. Furthermore, the LPC-induced degradation of inhibitory κBα was delayed under the conditions of deficient SUMOylation or the treatment of LXR agonist. After enhancing SUMOylation by knockdown SUMO-specific protease Sentrin-specific protease 1 (SENP1), the inhibition of GW3965 was rescued on LPC-mediated IL-8 expression. These findings indicate that LXR-mediated inflammatory gene repression correlates to the suppression of NF-κB pathway and SUMOylation. Our results suggest that LXR agonist exerts the anti-atherosclerotic role by attenuation of the NF-κB pathway in endothelial cells.


Asunto(s)
Células Endoteliales de la Vena Umbilical Humana/metabolismo , Interleucina-8/metabolismo , Receptores X del Hígado/metabolismo , Lisofosfatidilcolinas/farmacología , FN-kappa B/metabolismo , Transducción de Señal/efectos de los fármacos , Sumoilación/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Línea Celular , Humanos , Interleucina-8/biosíntesis , Receptores X del Hígado/agonistas , Monocitos/citología , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Biosíntesis de Proteínas/efectos de los fármacos
9.
Tumour Biol ; 37(9): 11893-11901, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27059736

RESUMEN

Protein phosphatase 4 catalytic subunit (PP4C) has been identified to be overexpressed in various solid cancers. However, to date, the role of PP4C in glioma remains elusive. In the present study, we aimed to detect PP4C expression in glioma patients and explore its function in glioma and prognostic significance in patients with glioma. The expression levels of PP4C mRNA and protein in 30 glioma tissue specimens and 10 non-cancerous brain tissue specimens were detected by qRT-PCR and Western blot analysis. Moreover, immunohistochemistry was performed to assess PP4C expression in 120 glioma patients. The effects of siRNA-mediated PP4C silencing on the proliferation, migration, and invasion of U251 and U87 glioma cells were assessed. We found that PP4C was upregulated in glioma tissue at both mRNA and protein levels compared with non-cancerous brain tissue. Univariate and multivariate analyses indicated that high PP4C expression was an independent prognostic factor for poor survival of glioma patients. Knockdown of PP4C reduced the proliferation, migration, and invasion of U251 and U87 cells. In conclusion, our findings suggest that PP4C plays an oncogenic role in glioma development and progression and might serve as a prognostic biomarker as well as a potential therapeutic target for glioma.


Asunto(s)
Neoplasias Encefálicas/genética , Proliferación Celular/genética , Regulación Neoplásica de la Expresión Génica , Glioma/genética , Fosfoproteínas Fosfatasas/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Western Blotting , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Niño , Preescolar , Femenino , Glioma/metabolismo , Glioma/patología , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Fosfoproteínas Fosfatasas/metabolismo , Pronóstico , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Adulto Joven
10.
J Mol Cell Cardiol ; 80: 166-74, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25636197

RESUMEN

Statins have beneficial pleiotropic effects beyond lipid lowering on the cardiovascular system. These cardio-protective effects are mediated through inhibition of the intracellular mevalonate pathway, by decreasing isoprenoid intermediate synthesis and the subsequent post-translational modification of small GTPases, such as Ras, Rho, and Rac. Impaired intracellular calcium handling is considered an important pathophysiologic mechanism responsible for cardiac dysfunction. Our study aimed at investigating the influence of mevalonate pathway, including its downstream small GTPases (Ras, RhoA, and Rac1) on anoxia-mediated alterations of calcium handling in H9c2 cardiomyocytes. Cultured H9c2 cardiomyocytes were exposed to acute anoxia after pretreatment with different drugs that specifically antagonize five key components in the mevalonate pathway, including 3-hydroxy-3-methylglutaryl-CoA reductase, farnesyl pyrophosphate synthase, Rho-kinase, Rac1 and Ras farnesyltransferase. Thereafter, we evaluated the effects of the mevalonate pathway on anoxia-induced cell death, expression of the sarcoplasmic reticulum calcium release channel (ryanodine receptor 2) and its regulator FK506-binding protein 12.6, as well as functional calcium release from intracellular calcium stores. Our experiments confirmed the role of prenylated proteins in regulating cardiomyocyte dysfunction, especially via RhoA- and Ras-related signaling pathways. Furthermore, our data demonstrated that inhibition of the mevalonate pathway could ameliorate anoxia-mediated calcium handling dysfunction with the up-regulated expression of FK506-binding protein 12.6 and consequently provided evidence for FK506-binding protein 12.6 as a "stabilizer" of ryanodine receptor 2.


Asunto(s)
Calcio/metabolismo , Hipoxia/metabolismo , Redes y Vías Metabólicas/efectos de los fármacos , Ácido Mevalónico/metabolismo , Proteínas de Unión a Tacrolimus/metabolismo , Animales , Señalización del Calcio/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Regulación hacia Abajo , Regulación de la Expresión Génica/efectos de los fármacos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Hipoxia/genética , Espacio Intracelular/metabolismo , Mioblastos Cardíacos/efectos de los fármacos , Mioblastos Cardíacos/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Ratas , Proteínas de Unión a Tacrolimus/genética
11.
Sci Rep ; 13(1): 8010, 2023 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-37198237

RESUMEN

Body mass index is a widely used but poor predictor of adiposity in populations with excessive fat-free mass. Rigorous predictive models validated specifically in a nationally representative sample of the US population and that could be used for calibration purposes are needed. The objective of this study was to develop and validate prediction equations of body fat percentage obtained from Dual Energy X-ray Absorptiometry using body mass index (BMI) and socio-demographics. We used the National Health and Nutrition Examination Survey (NHANES) data from 5931 and 2340 adults aged 20 to 69 in 1999-2002 and 2003-2006, respectively. A supervised machine learning using ordinary least squares and a validation set approach were used to develop and select best models based on R2 and root mean square error. We compared our findings with other published models and utilized our best models to assess the amount of bias in the association between predicted body fat and elevated low-density lipoprotein (LDL). Three models included BMI, BMI2, age, gender, education, income, and interaction terms and produced R-squared values of 0.87 and yielded the smallest standard errors of estimation. The amount of bias in the association between predicted BF% and elevated LDL from our best model was -0.005. Our models provided strong predictive abilities and low bias compared to most published models. Its strengths rely on its simplicity and its ease of use in low-resource settings.


Asunto(s)
Tejido Adiposo , Composición Corporal , Índice de Masa Corporal , Encuestas Nutricionales , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Factores Sexuales , Absorciometría de Fotón
12.
Natl Sci Rev ; 10(6): nwad069, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37181085

RESUMEN

With the aid of the newly developed 'Sunway' heterogeneous-architecture supercomputer, which has world-leading HPC (high-performance computer) capability, a series of high-resolution coupled Earth system models (SW-HRESMs) with up to 5 km of atmosphere and 3 km of ocean have been developed. These models can meet the needs of multiscale interaction studies with different computational costs. Here we describe the progress of SW-HRESMs development, with an overview of the major advancements made by the international Earth science community in HR-ESMs. We also show the preliminary results of SW-HRESMs with regard to capturing major weather-climate extremes in the atmosphere and ocean, stressing the importance of permitted clouds and ocean submesoscale eddies in modeling tropical cyclones and eddy-mean flow interactions, and paving the way for further model development to resolve finer scales with even higher resolution and more realistic physics. Finally, in addition to increasing model resolution, the development procedure for a non-hydrostatic cloud and ocean submesoscale resolved ESM is discussed, laying out the major scientific directions of such a huge modeling advancement.

13.
Proc Natl Acad Sci U S A ; 106(42): 18028-33, 2009 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-19815510

RESUMEN

As the most prototypical G protein-coupled receptor, beta-adrenergic receptor (betaAR) regulates the pace and strength of heart beating by enhancing and synchronizing L-type channel (LCC) Ca(2+) influx, which in turn elicits greater sarcoplasmic reticulum (SR) Ca(2+) release flux via ryanodine receptors (RyRs). However, whether and how betaAR-protein kinase A (PKA) signaling directly modulates RyR function remains elusive and highly controversial. By using unique single-channel Ca(2+) imaging technology, we measured the response of a single RyR Ca(2+) release unit, in the form of a Ca(2+) spark, to its native trigger, the Ca(2+) sparklet from a single LCC. We found that acute application of the selective betaAR agonist isoproterenol (1 microM, < or = 20 min) increased triggered spark amplitude in an LCC unitary current-independent manner. The increased ratio of Ca(2+) release flux underlying a Ca(2+) spark to SR Ca(2+) content indicated that betaAR stimulation helps to recruit additional RyRs in synchrony. Quantification of sparklet-spark kinetics showed that betaAR stimulation synchronized the stochastic latency and increased the fidelity (i.e., chance of hit) of LCC-RyR intermolecular signaling. The RyR modulation was independent of the increased SR Ca(2+) content. The PKA antagonists Rp-8-CPT-cAMP (100 microM) and H89 (10 microM) both eliminated these effects, indicating that betaAR acutely modulates RyR activation via the PKA pathway. These results demonstrate unequivocally that RyR activation by a single LCC is accelerated and synchronized during betaAR stimulation. This molecular mechanism of sympathetic regulation will permit more fundamental studies of altered betaAR effects in cardiovascular diseases.


Asunto(s)
Canales de Calcio Tipo L/metabolismo , Miocitos Cardíacos/metabolismo , Receptores Adrenérgicos beta/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Agonistas Adrenérgicos beta/farmacología , Animales , Señalización del Calcio/efectos de los fármacos , Señalización del Calcio/fisiología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Técnicas In Vitro , Isoproterenol/farmacología , Microscopía Confocal , Contracción Miocárdica/fisiología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/fisiología , Técnicas de Placa-Clamp , Ratas , Ratas Sprague-Dawley , Retículo Sarcoplasmático/metabolismo , Transducción de Señal/fisiología
14.
Genome Biol ; 23(1): 165, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35915475

RESUMEN

BACKGROUND: Due to post-cleavage residence of the Cas9-sgRNA complex at its target, Cas9-induced DNA double-strand breaks (DSBs) have to be exposed to engage DSB repair pathways. Target interaction of Cas9-sgRNA determines its target binding affinity and modulates its post-cleavage target residence duration and exposure of Cas9-induced DSBs. This exposure, via different mechanisms, may initiate variable DNA damage responses, influencing DSB repair pathway choices and contributing to mutational heterogeneity in genome editing. However, this regulation of DSB repair pathway choices is poorly understood. RESULTS: In repair of Cas9-induced DSBs, repair pathway choices vary widely at different target sites and classical nonhomologous end joining (c-NHEJ) is not even engaged at some sites. In mouse embryonic stem cells, weakening the target interaction of Cas9-sgRNA promotes bias towards c-NHEJ and increases target dissociation and reduces target residence of Cas9-sgRNAs in vitro. As an important strategy for enhancing homology-directed repair, inactivation of c-NHEJ aggravates off-target activities of Cas9-sgRNA due to its weak interaction with off-target sites. By dislodging Cas9-sgRNA from its cleaved targets, DNA replication alters DSB end configurations and suppresses c-NHEJ in favor of other repair pathways, whereas transcription has little effect on c-NHEJ engagement. Dissociation of Cas9-sgRNA from its cleaved target by DNA replication may generate three-ended DSBs, resulting in palindromic fusion of sister chromatids, a potential source for CRISPR/Cas9-induced on-target chromosomal rearrangements. CONCLUSIONS: Target residence of Cas9-sgRNA modulates DSB repair pathway choices likely through varying dissociation of Cas9-sgRNA from cleaved DNA, thus widening on-target and off-target mutational spectra in CRISPR/Cas9 genome editing.


Asunto(s)
Roturas del ADN de Doble Cadena , Edición Génica , Animales , Sistemas CRISPR-Cas , ADN , Reparación del ADN por Unión de Extremidades , Reparación del ADN , Edición Génica/métodos , Ratones
15.
Org Lett ; 23(3): 706-710, 2021 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-33428416

RESUMEN

Ir-catalyzed asymmetric tandem allylation/iso-Pictet-Spengler cyclization of arylidenaminomalonates with indolyl allylic methyl carbonates was successfully developed, which provided a direct and practical approach to access synthetically useful and biologically active tetrahydro-γ-carboline derivatives bearing multiple functional groups and stereogenic centers in good to high yields and excellent stereoselective control (44%-96% yields, >20:1 dr, 94% → 99% ee). A wide range of substrate generality, easily available substrates, and simple chiral catalytic system displayed great potential practicality of this efficient protocol.

16.
PLoS Biol ; 5(2): e21, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17214508

RESUMEN

Pressure overload-induced hypertrophy is a key step leading to heart failure. The Ca(2+)-induced Ca(2+) release (CICR) process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca(2+) channel (LCC) and ryanodine receptors (RyRs) in aortic stenosis rat models of compensated (CHT) and decompensated (DHT) hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of "intermolecular failure." Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca(2+) release, visualized as "Ca(2+) spikes," became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca(2+) transients in CHT. These data suggested that, within a certain limit, termed the "stability margin," mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of "hidden" intermolecular failure in CHT has important clinical implications.


Asunto(s)
Canales de Calcio Tipo L/metabolismo , Señalización del Calcio/fisiología , Insuficiencia Cardíaca/metabolismo , Hipertrofia Ventricular Izquierda/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Animales , Aorta/cirugía , Estenosis de la Válvula Aórtica/metabolismo , Estenosis de la Válvula Aórtica/patología , Modelos Animales de Enfermedad , Insuficiencia Cardíaca/patología , Hipertrofia Ventricular Izquierda/patología , Microscopía Confocal , Contracción Miocárdica/fisiología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Técnicas de Placa-Clamp , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley
17.
Chem Commun (Camb) ; 56(67): 9691-9694, 2020 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-32697814

RESUMEN

Here, we developed an expedient access route to highly functionalized pyrroles from readily available α-amino acid ester hydrochlorides and alkynals via a cascade condensation/intramolecular cyclization followed by a unique C-N ester migration process. A variety of 1,2,3-trisubstituted pyrroles, which were difficult to acquire with the common methodologies, were successfully prepared in good yields under mild conditions.

18.
Chem Commun (Camb) ; 56(22): 3333-3336, 2020 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-32090227

RESUMEN

Facile access to quaternary α-trifluoromethyl α-amino acids has been developed. This sequential reaction involves an Ir-catalyzed asymmetric allylation of α-trifluoromethyl aldimine esters followed by an unprecedented kinetic resolution.


Asunto(s)
Aminoácidos/química , Iridio/química , Aminoácidos/síntesis química , Catálisis , Cristalografía por Rayos X , Iminas/química , Cinética , Conformación Molecular , Estereoisomerismo
19.
Food Addit Contam Part B Surveill ; 13(2): 77-81, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31905107

RESUMEN

In this study fluoride in 170 tea samples from Shandong province (China) was determined using a selective ion electrode. The fluoride concentrations ranged from 31.2 to 338 mg/kg with an average of 119 mg/kg. The mean fluoride concentrations were 164, 121, 98.7 and 96.8 mg/kg, which corresponded to Pu'erh tea, green tea, oolong tea and black tea, respectively. Moreover, 4.7% of the analysed samples exceed the legal limit of 200 mg/kg recommended by China. The estimated daily intake of fluoride via drinking tea for an adult was between 0.655 and 1.07 mg/person/day, which were lower than the provisional maximum tolerable daily intake value of 3.5 mg/person/day set by the National Health and Family Planning Commission of the People's Republic of China. In future, maintaining a surveillance programme to monitor the trend of fluoride in tea is necessary for food safety and human health.


Asunto(s)
Fluoruros/análisis , Contaminación de Alimentos/análisis , Té/química , China , Exposición Dietética , Análisis de los Alimentos , Humanos , Medición de Riesgo
20.
Autophagy ; 16(12): 2206-2218, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-31971848

RESUMEN

How energy deprivation induces macroautophagy/autophagy is not fully understood. Here, we show that Atg11, a receptor protein for cargo recognition in selective autophagy, is required for the initiation of glucose starvation-induced autophagy. Upon glucose starvation, Atg11 facilitates the interaction between Snf1 and Atg1, thus is required for Snf1-dependent Atg1 activation. Phagophore assembly site (PAS) formation requires Atg11 via its control of the association of Atg17 with Atg29-Atg31. The binding of Atg11 with Atg9 is crucial for recruiting Atg9 vesicles to the PAS and, thus, glucose starvation-induced autophagy. We propose Atg11 as a key initiation factor controlling multiple key steps in energy deprivation-induced autophagy. Abbreviations: AMPK: AMP-activated protein kinase; Ams1: α-mannosidase; Ape1: aminopeptidase I; Cvt: cytoplasm-to-vacuole targeting; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; GFP: green fluorescent protein; MBP: myelin basic protein; MMS: methanesulfonate; PAS: phagophore assembly site; PNBM: p-nitrobenzyl mesylate; SD-G: glucose starvation medium; SD-N: nitrogen starvation medium; ULK1, unc-51 like autophagy activating kinase 1; WT: wild type.


Asunto(s)
Proteínas Relacionadas con la Autofagia/metabolismo , Autofagia , Glucosa/deficiencia , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas Relacionadas con la Autofagia/química , Modelos Biológicos , Complejos Multiproteicos/metabolismo , Fagosomas/metabolismo , Dominios Proteicos , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Transporte Vesicular/química
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