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1.
Nat Mater ; 23(5): 688-694, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38413812

RESUMEN

Enabled by surface-mediated equilibration, physical vapour deposition can create high-density stable glasses comparable with liquid-quenched glasses aged for millions of years. Deposition is often performed at various rates and temperatures on rigid substrates to control the glass properties. Here we demonstrate that on soft, rubbery substrates, surface-mediated equilibration is enhanced up to 170 nm away from the interface, forming stable glasses with densities up to 2.5% higher than liquid-quenched glasses within 2.5 h of deposition. Gaining similar properties on rigid substrates would require 10 million times slower deposition, taking ~3,000 years. Controlling the modulus of the rubbery substrate provides control over the glass structure and density at constant deposition conditions. These results underscore the significance of substrate elasticity in manipulating the properties of the mobile surface layer and thus the glass structure and properties, allowing access to deeper states of the energy landscape without prohibitively slow deposition rates.

2.
Plant Physiol ; 192(3): 2374-2393, 2023 07 03.
Artículo en Inglés | MEDLINE | ID: mdl-37018475

RESUMEN

The morphological diversity of the inflorescence determines flower and seed production, which is critical for plant adaptation. Hall's panicgrass (Panicum hallii, P. hallii) is a wild perennial grass that has been developed as a model to study perennial grass biology and adaptive evolution. Highly divergent inflorescences have evolved between the 2 major ecotypes in P. hallii, the upland ecotype (P. hallii var hallii, HAL2 genotype) with compact inflorescence and large seed and the lowland ecotype (P. hallii var filipes, FIL2 genotype) with an open inflorescence and small seed. Here we conducted a comparative analysis of the transcriptome and DNA methylome, an epigenetic mark that influences gene expression regulation, across different stages of inflorescence development using genomic references for each ecotype. Global transcriptome analysis of differentially expressed genes (DEGs) and co-expression modules underlying the inflorescence divergence revealed the potential role of cytokinin signaling in heterochronic changes. Comparing DNA methylome profiles revealed a remarkable level of differential DNA methylation associated with the evolution of P. hallii inflorescence. We found that a large proportion of differentially methylated regions (DMRs) were located in the flanking regulatory regions of genes. Intriguingly, we observed a substantial bias of CHH hypermethylation in the promoters of FIL2 genes. The integration of DEGs, DMRs, and Ka/Ks ratio results characterized the evolutionary features of DMR-associated DEGs that contribute to the divergence of the P. hallii inflorescence. This study provides insights into the transcriptome and epigenetic landscape of inflorescence divergence in P. hallii and a genomic resource for perennial grass biology.


Asunto(s)
Ecotipo , Panicum , Panicum/genética , Transcriptoma/genética , Inflorescencia/genética , Epigenoma/genética , Regulación de la Expresión Génica de las Plantas , Metilación de ADN/genética
3.
Toxicol Appl Pharmacol ; 488: 116970, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38777098

RESUMEN

Soman produces excitotoxic effects by inhibiting acetylcholinesterase in the cholinergic synapses and neuromuscular junctions, resulting in soman-induced sustained status epilepticus (SSE). Our previous work showed delayed intramuscular (i.m.) treatment with A1 adenosine receptor agonist N-bicyclo-[2.2.1]-hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA) alone suppressed soman-induced SSE and prevented neuropathology. Using this same rat soman seizure model, we tested if delayed therapy with ENBA (60 mg/kg, i.m.) would terminate seizure, protect neuropathology, and aid in survival when given in conjunction with current standard medical countermeasures (MCMs): atropine sulfate, 2-PAM, and midazolam (MDZ). Either 15- or 30-min following soman-induced SSE onset, male rats received atropine and 2-PAM plus either MDZ or MDZ + ENBA. Electroencephalographic (EEG) activity, physiologic parameters, and motor function were recorded. Either 2- or 14-days following exposure surviving rats were euthanized and perfused for histology. All animals treated with MDZ + ENBA at both time points had 100% EEG seizure termination and reduced total neuropathology compared to animals treated with MDZ (2-day, p = 0.015 for 15-min, p = 0.002 for 30-min; 14-day, p < 0.001 for 15-min, p = 0.006 for 30-min), showing ENBA enhanced MDZ's anticonvulsant and neuroprotectant efficacy. However, combined MDZ + ENBA treatment, when compared to MDZ treatment groups, had a reduction in the 14-day survival rate regardless of treatment time, indicating possible enhancement of MDZ's neuronal inhibitory effects by ENBA. Based on our findings, ENBA shows promise as an anticonvulsant and neuroprotectant in a combined treatment regimen following soman exposure; when given as an adjunct to standard MCMs, the dose of ENBA needs to be adjusted.


Asunto(s)
Agonistas del Receptor de Adenosina A1 , Ratas Sprague-Dawley , Convulsiones , Soman , Animales , Soman/toxicidad , Masculino , Agonistas del Receptor de Adenosina A1/farmacología , Ratas , Inyecciones Intramusculares , Convulsiones/inducido químicamente , Convulsiones/tratamiento farmacológico , Convulsiones/prevención & control , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/administración & dosificación , Fármacos Neuroprotectores/uso terapéutico , Anticonvulsivantes/administración & dosificación , Electroencefalografía/efectos de los fármacos , Adenosina/análogos & derivados , Adenosina/administración & dosificación , Adenosina/farmacología , Atropina/farmacología , Atropina/administración & dosificación , Estado Epiléptico/inducido químicamente , Estado Epiléptico/tratamiento farmacológico , Midazolam/farmacología , Midazolam/uso terapéutico
4.
Angew Chem Int Ed Engl ; 63(20): e202320243, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38472114

RESUMEN

Since Friedrich Wöhler's groundbreaking synthesis of urea in 1828, organic synthesis over the past two centuries has predominantly relied on the exploration and utilization of chemical reactions rooted in two-electron heterolytic ionic chemistry. While one-electron homolytic radical chemistry is both rich in fundamental reactivities and attractive with practical advantages, the synthetic application of radical reactions has been long hampered by the formidable challenges associated with the control over reactivity and selectivity of high-energy radical intermediates. To fully harness the untapped potential of radical chemistry for organic synthesis, there is a pressing need to formulate radically different concepts and broadly applicable strategies to address these outstanding issues. In pursuit of this objective, researchers have been actively developing metalloradical catalysis (MRC) as a comprehensive framework to guide the design of general approaches for controlling over reactivity and stereoselectivity of homolytic radical reactions. Essentially, MRC exploits the metal-centered radicals present in open-shell metal complexes as one-electron catalysts for homolytic activation of substrates to generate metal-entangled organic radicals as the key intermediates to govern the reaction pathway and stereochemical course of subsequent catalytic radical processes. Different from the conventional two-electron catalysis by transition metal complexes, MRC operates through one-electron chemistry utilizing stepwise radical mechanisms.

5.
Biophys J ; 122(7): 1390-1399, 2023 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-36872604

RESUMEN

Optical methods for examining cellular structure based on endogenous contrast rely on analysis of refractive index changes to discriminate cell phenotype. These changes can be visualized using techniques such as phase contrast microscopy, detected by light scattering, or analyzed numerically using quantitative phase imaging. The statistical variations of refractive index at the nanoscale can be quantified using disorder strength, a metric seen to increase with neoplastic change. In contrast, the spatial organization of these variations is typically characterized using a fractal dimension, which is also seen to increase with cancer progression. Here, we seek to link these two measurements using multiscale measurements of optical phase to calculate disorder strength and in turn to determine the fractal dimension of the structures. First, quantitative phase images are analyzed to show that the disorder strength metric changes with resolution. The trend of disorder strength with length scales is analyzed to determine the fractal dimension of the cellular structures. Comparison of these metrics is presented for different cell lines with varying phenotypes including MCF10A, MCF7, BT474, HT-29, A431, and A549 cell lines, in addition to three cell populations with modified phenotypes. Our results show that disorder strength and fractal dimension can both be obtained with quantitative phase imaging and that these metrics can independently distinguish between different cell lines. Furthermore, their combined use presents a new approach for better understanding cellular restructuring during different pathways.


Asunto(s)
Línea Celular Tumoral , Fractales , Microscopía de Contraste de Fase , Línea Celular Tumoral/citología , Humanos , Fenotipo
6.
J Am Chem Soc ; 145(21): 11622-11632, 2023 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-37129381

RESUMEN

Asymmetric radical bicyclization processes have been developed via metalloradical catalysis (MRC) to stereoselectively construct chiral chromanones and chromanes bearing fused cyclopropanes. Through optimization of a versatile D2-symmetric chiral amidoporphyrin ligand platform, a Co(II)-metalloradical system can homolytically activate both diazomalonates and α-aryldiazomethanes containing different alkene functionalities under mild conditions for effective radical bicyclization, delivering cyclopropane-fused tricyclic chromanones and chromanes, respectively, in high yields with excellent control of both diastereoselectivities and enantioselectivities. Combined computational and experimental studies, including the electron paramagnetic resonance (EPR) detection and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) trapping of key radical intermediates, shed light on the working details of the underlying stepwise radical mechanisms of the Co(II)-catalyzed bicyclization processes. The two catalytic radical processes provide effective synthetic tools for stereoselective construction of valuable cyclopropane-fused chromanones and chromanes with newly generated contiguous stereogenic centers. As a specific demonstration of synthetic application, the Co(II)-catalyzed radical bicyclization has been employed as a key step for the first asymmetric total synthesis of the natural product (+)-Radulanin J.

7.
Mol Phylogenet Evol ; 189: 107938, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37820761

RESUMEN

The order Sordariales is taxonomically diverse, and harbours many species with different lifestyles and large economic importance. Despite its importance, a robust genome-scale phylogeny, and associated comparative genomic analysis of the order is lacking. In this study, we examined whole-genome data from 99 Sordariales, including 52 newly sequenced genomes, and seven outgroup taxa. We inferred a comprehensive phylogeny that resolved several contentious relationships amongst families in the order, and cleared-up intrafamily relationships within the Podosporaceae. Extensive comparative genomics showed that genomes from the three largest families in the dataset (Chaetomiaceae, Podosporaceae and Sordariaceae) differ greatly in GC content, genome size, gene number, repeat percentage, evolutionary rate, and genome content affected by repeat-induced point mutations (RIP). All genomic traits showed phylogenetic signal, and ancestral state reconstruction revealed that the variation of the properties stems primarily from within-family evolution. Together, the results provide a thorough framework for understanding genome evolution in this important group of fungi.


Asunto(s)
Genómica , Sordariales , Humanos , Filogenia , Genómica/métodos , Genoma , Sordariales/genética , Secuencia de Bases , Evolución Molecular
8.
Int J Mol Sci ; 24(15)2023 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-37569260

RESUMEN

Sickle cell disease (SCD) is an inherited hematological disorder associated with high mortality rates, particularly in sub-Saharan Africa. SCD arises due to the polymerization of sickle hemoglobin, which reduces flexibility of red blood cells (RBCs), causing blood vessel occlusion and leading to severe morbidity and early mortality rates if untreated. While sickle solubility tests are available to sub-Saharan African population as a means for detecting sickle hemoglobin (HbS), the test falls short in assessing the severity of the disease and visualizing the degree of cellular deformation. Here, we propose use of holographic cytometry (HC), a high throughput, label-free imaging modality, for comprehensive morphological profiling of RBCs as a means to detect SCD. For this study, more than 2.5 million single-cell holographic images from normal and SCD patient samples were collected using the HC system. We have developed an approach for specially defining training data to improve machine learning classification. Here, we demonstrate the deep learning classifier developed using this approach can produce highly accurate classification, even on unknown patient samples.


Asunto(s)
Anemia de Células Falciformes , Aprendizaje Profundo , Enfermedades Hematológicas , Humanos , Hemoglobina Falciforme , Anemia de Células Falciformes/diagnóstico , Eritrocitos
9.
J Am Chem Soc ; 144(5): 2368-2378, 2022 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-35099966

RESUMEN

α-Alkynyldiazomethanes, generated in situ from the corresponding sulfonyl hydrazones in the presence of a base, can serve as effective metalloradicophiles in Co(II)-based metalloradical catalysis (MRC) for asymmetric cyclopropanation of alkenes. With D2-symmetric chiral amidoporphyrin 2,6-DiMeO-QingPhyrin as the optimal supporting ligand, the Co(II)-based metalloradical system can efficiently activate different α-alkynyldiazomethanes at room temperature for highly asymmetric cyclopropanation of a broad range of alkenes. This catalytic radical process provides a general synthetic tool for stereoselective construction of alkynyl cyclopropanes in high yields with high both diastereoselectivity and enantioselectivity. Combined computational and experimental studies offer several lines of evidence in support of the underlying stepwise radical mechanism for the Co(II)-catalyzed olefin cyclopropanation involving a unique α-metalloradical intermediate that is associated with two resonance forms of α-Co(III)-propargyl radical and γ-Co(III)-allenyl radical. The resulting enantioenriched alkynyl cyclopropanes, as showcased with several stereospecific transformations, may serve as valuable chiral building blocks for stereoselective organic synthesis.


Asunto(s)
Alquenos/química , Compuestos de Diazonio/química , Cobalto , Ciclización , Estructura Molecular
10.
J Am Chem Soc ; 143(30): 11670-11678, 2021 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-34292709

RESUMEN

While alkyl radicals have been well demonstrated to undergo both 1,5- and 1,6-hydrogen atom abstraction (HAA) reactions, 1,4-HAA is typically a challenging process both entropically and enthalpically. Consequently, chemical transformations based on 1,4-HAA have been scarcely developed. Guided by the general mechanistic principles of metalloradical catalysis (MRC), 1,4-HAA has been successfully incorporated as a key step, followed by 4-exo-tet radical substitution (RS), for the development of a new catalytic radical process that enables asymmetric 1,4-C-H alkylation of diazoketones for stereoselective construction of cyclobutanone structures. The key to success is the optimization of the Co(II)-based metalloradical catalyst through judicious modulation of D2-symmetric chiral amidoporphyrin ligand to adopt proper steric, electronic, and chiral environments that can utilize a network of noncovalent attractive interactions for effective activation of the substrate and subsequent radical intermediates. Supported by an optimal chiral ligand, the Co(II)-based metalloradical system, which operates under mild conditions, is capable of 1,4-C-H alkylation of α-aryldiazoketones with varied electronic and steric properties to construct chiral α,ß-disubstituted cyclobutanones in good to high yields with high diastereoselectivities and enantioselectivities, generating dinitrogen as the only byproduct. Combined computational and experimental studies have shed light on the mechanistic details of the new catalytic radical process, including the revelation of facile 1,4-HAA and 4-exo-tet-RS steps. The resulting enantioenriched α,ß-disubstituted cyclobutanones, as showcased with several enantiospecific transformations to other types of cyclic structures, may find useful applications in stereoselective organic synthesis.


Asunto(s)
Cobalto/química , Complejos de Coordinación/química , Ciclobutanos/síntesis química , Hidrógeno/química , Catálisis , Ciclobutanos/química , Radicales Libres/química , Conformación Molecular , Estereoisomerismo
11.
J Am Chem Soc ; 143(29): 11130-11140, 2021 07 28.
Artículo en Inglés | MEDLINE | ID: mdl-34260202

RESUMEN

Radical cascade cyclization reactions are highly attractive synthetic tools for the construction of polycyclic molecules in organic synthesis. While it has been successfully implemented in diastereoselective synthesis of natural products and other complex compounds, radical cascade cyclization faces a major challenge of controlling enantioselectivity. As the first application of metalloradical catalysis (MRC) for controlling enantioselectivity as well as diastereoselectivity in radical cascade cyclization, we herein report the development of a Co(II)-based catalytic system for asymmetric radical bicyclization of 1,6-enynes with diazo compounds. Through the fine-tuning of D2-symmetric chiral amidoporphyrins as the supporting ligands, the Co(II)-catalyzed radical cascade process, which proceeds in a single operation under mild conditions, enables asymmetric construction of multisubstituted cyclopropane-fused tetrahydrofurans bearing three contiguous stereogenic centers, including two all-carbon quaternary centers, in high yields with excellent stereoselectivities. Combined computational and experimental studies have shed light on the underlying stepwise radical mechanism for this new Co(II)-based cascade bicyclization that involves the relay of several Co-supported C-centered radical intermediates, including α-, ß-, γ-, and ε-metalloalkyl radicals. The resulting enantioenriched cyclopropane-fused tetrahydrofurans that contain a trisubstituted vinyl group at the bridgehead, as showcased in several stereospecific transformations, may serve as useful intermediates for stereoselective organic synthesis. The successful demonstration of this new asymmetric radical process via Co(II)-MRC points out a potentially general approach for controlling enantioselectivity as well as diastereoselectivity in synthetically attractive radical cascade reactions.


Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Ciclización , Radicales Libres/química , Estructura Molecular , Estereoisomerismo
12.
Toxicol Appl Pharmacol ; 419: 115515, 2021 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-33798593

RESUMEN

Exposure to organophosphorus nerve agents (NAs) like sarin (GB) and soman (GD) can lead to sustained seizure activity, or status epilepticus (SE). Previous research has shown that activation of A1 adenosine receptors (A1ARs) can inhibit neuronal excitability, which could aid in SE termination. Two A1AR agonists, 2-Chloro-N6-cyclopentyladenosine (CCPA) and N-Bicyclo(2.2.1)hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA), were effective in terminating GD-induced SE in rats when administered via intraperitoneal (IP) injection. However, IP injection is not a clinically relevant route of administration. This study evaluated the efficacy of these agonists in terminating NA-induced SE when administered via intramuscular (IM) route. Adult male rats were exposed subcutaneously (SC) to either GB (150 µg/kg) or GD (90 µg/kg) and were treated with ENBA or CCPA at 15, 30, or 60 min after seizure onset or left untreated. Up to 7 days after exposure, deeply anesthetized rats were euthanized and perfused brains were removed for histologic assessment of neuropathology (i.e., neuronal damage) in six brain regions (amygdala, cerebral cortex, piriform cortex, thalamus, dorsal hippocampus, and ventral hippocampus). A total neuropathy score (0-24) was determined for each rat by adding the scores from each of the six regions. The higher the total score the more severe the neuropathology. With the GB model and 60 min treatment delay, ENBA-treated rats experienced 78.6% seizure termination (N = 14) and reduced neuropathology (11.6 ± 2.6, N = 5), CCPA-treated rats experienced 85.7% seizure termination (N = 14) and slightly reduced neuropathology (20.7 ± 1.8, N = 6), and untreated rats experienced no seizure termination (N = 13) and severe neuropathology (22.3 ± 1.0, N = 4). With the GD model and 60 min treatment delay, ENBA-treated rats experienced 92.9% seizure termination (N = 14) and reduced neuropathology (13.96 ± 1.8, N = 9), CCPA-treated rats experienced 78.6% seizure termination (N = 14) and slightly reduced neuropathology (22.0 ± 0.9, N = 10); and untreated rats experienced 16.7% seizure termination (N = 12) and severe neuropathology (22.0 ± 1.8, N = 5). While ENBA and CCPA both demonstrate a clear ability to terminate SE when administered up to 60 min after seizure onset, ENBA offers more neuroprotection, making it a promising candidate for NA-induced SE.


Asunto(s)
Agonistas del Receptor de Adenosina A1/administración & dosificación , Adenosina/análogos & derivados , Anticonvulsivantes/administración & dosificación , Encéfalo/efectos de los fármacos , Desoxiadenosinas/administración & dosificación , Fármacos Neuroprotectores/administración & dosificación , Norbornanos/administración & dosificación , Sarín , Soman , Estado Epiléptico/prevención & control , Adenosina/administración & dosificación , Animales , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/fisiopatología , Modelos Animales de Enfermedad , Esquema de Medicación , Inyecciones Intramusculares , Masculino , Ratas Sprague-Dawley , Estado Epiléptico/inducido químicamente , Estado Epiléptico/metabolismo , Estado Epiléptico/patología , Factores de Tiempo
13.
Exp Cell Res ; 390(1): 111926, 2020 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-32112801

RESUMEN

Concomitant treatment with deferoxamine (DFO) protects neural cells from iron and heme-mediated oxidative injury, but also disrupts cell responses to iron loading that may be protective. We hypothesized that DFO treatment and withdrawal would subsequently increase neuronal vulnerability to hemoglobin. Pretreatment with DFO followed by its washout increased neuronal loss after subsequent hemoglobin exposure by 3-4-fold compared with control vehicle-pretreated cultures. This was associated with reduced ferritin induction by hemoglobin; expression of heme oxygenase-1, which catalyzes iron release from heme, was not altered. Increased neuronal loss was prevented by exogenous apoferritin or by continuing DFO or antioxidants throughout the experimental course. Cell nonheme iron levels after hemoglobin treatment were similar in DFO-pretreated and control cultures. These results indicate that DFO deconditions neurons and subsequently increases their vulnerability to heme-mediated injury. Its net effect after CNS hemorrhage may be highly dependent on the timing and duration of its administration. Withdrawal of DFO while heme or iron levels remain elevated may be deleterious, and may negate any benefit of prior concomitant therapy.


Asunto(s)
Deferoxamina/farmacología , Hemoglobinas/farmacología , Neuronas/efectos de los fármacos , Sideróforos/farmacología , Animales , Células Cultivadas , Ferritinas/genética , Ferritinas/metabolismo , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Hemoglobinas/metabolismo , Hierro/metabolismo , Ratones , Neuronas/metabolismo , Estrés Oxidativo
14.
J Emerg Med ; 59(4): e127-e130, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32739130

RESUMEN

BACKGROUND: Intracardiac foreign bodies have been described in the literature, however, they are rare entities, particularly in pediatric patients. We present a case of a teenage boy diagnosed with perimyocarditis who was found to have an unexpected underlying etiology: an unknowingly swallowed sewing pin. CASE REPORT: A 17-year-old boy presented to the Emergency Department with 3 days of chest pain suggestive of perimyocarditis, in the absence of prodromal symptoms or trauma. Electrocardiogram at the time of presentation demonstrated diffuse ST-segment elevation consistent with perimyocarditis. A chest radiograph was significant for a linear density in the anterior mid chest, concerning for foreign body. Chest computed tomography confirmed the presence of a 3.5-cm linear metallic foreign body within the right ventricle. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case demonstrates the need to consider alternative etiologies for perimyocarditis, especially in the absence of the typical prodromal symptoms. In addition, it highlights the potential devastating complications of foreign body ingestion and challenges the paradigm that ingested sharp linear foreign bodies < 5 cm in length rarely cause problems.


Asunto(s)
Cuerpos Extraños , Adolescente , Arritmias Cardíacas , Electrocardiografía , Servicio de Urgencia en Hospital , Cuerpos Extraños/complicaciones , Cuerpos Extraños/diagnóstico , Humanos , Masculino , Tomografía Computarizada por Rayos X
15.
Toxicol Mech Methods ; 29(5): 322-333, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30558458

RESUMEN

The efficacy of anticonvulsant therapies to stop seizure activities following organophosphorus nerve agents (NAs) has been documented as being time-dependent. We utilized the guinea pig NA-seizure model to compare the effectiveness of phencynonate (PCH) and scopolamine (SCP) when given at the early (at time of seizure onset) or late (40 min after seizure onset) phase of seizure progression. PCH possesses both anticholinergic and anti-NMDA activities, while SCP is a purely anti-muscarinic compound. Animals with cortical electrodes were pretreated with pyridostigmine bromide 30 min prior to exposure to a 2.0 x LD50 subcutaneous dose of a NA (GA, GB, GD, GF, VR, or VX), followed one min later with atropine sulfate and 2-PAM. At either early or late phase, animals were treated with either PCH or SCP and the 24-h anticonvulsant ED50 doses were determined. When administered at seizure onset, PCH, and SCP were both effective at terminating seizure activity against all NAs, with ED50 values for SCP generally being lower. At the 40 min time, ED50 values were obtained following GA, GD, GF, and VR challenges for SCP, but ED50 value was obtained only following GD for PCH, indicating a superior efficacy of SCP. When seizure activity was controlled, a significant improvement in weight loss, neuropathology, and survival was observed, regardless of treatment or NA. Overall, these results demonstrate the differing efficacies of these two similarly structured anticholinergic compounds with delayed administration and warrant further investigation into the timing and mechanisms of the seizure maintenance phase in different animal models.


Asunto(s)
Anticonvulsivantes/farmacología , Compuestos Aza/farmacología , Encéfalo/efectos de los fármacos , Glicolatos/farmacología , Agentes Nerviosos/toxicidad , Compuestos Organofosforados/toxicidad , Escopolamina/farmacología , Convulsiones/prevención & control , Edad de Inicio , Animales , Anticonvulsivantes/administración & dosificación , Compuestos Aza/administración & dosificación , Encéfalo/patología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Glicolatos/administración & dosificación , Cobayas , Dosificación Letal Mediana , Masculino , Escopolamina/administración & dosificación , Convulsiones/inducido químicamente , Convulsiones/patología
16.
J Org Chem ; 83(4): 2382-2388, 2018 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-29333860

RESUMEN

2-Aminophenyl-1H-pyrazole has been identified as a viable directing group to promote copper(II)-mediated ortho-selective sp2 C-H bond tandem alkynylation/annulation of anilides with terminal alkynes to offer arylmethylene isoindolinones. Meanwhile, copper(II)-mediated ortho-selective sp2 C-H hydroxylation of anilides has also been optimized as the major reaction pathway by using Cu(OAc)2 as the promoter and 1,1,3,3-tetramethylguanidine as an organic base. Recovery of the directing group was achieved by hydrazinolysis for arylmethylene isoindolinones and basic hydrolysis for the hydroxylation products.

17.
Phys Chem Chem Phys ; 20(46): 28990-29000, 2018 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-30238093

RESUMEN

Cation site occupation is an important determinant of materials properties, especially in a complex system with multiple cations such as in ternary spinels. Many methods for extracting the cation site information have been explored in the past, including analysis of spectra obtained through K-edge X-ray absorption spectroscopy (XAS). In this work, we measure the effectiveness of X-ray emission spectroscopy (XES) for determining the cation site occupation. As a test system we use spinel phase CoxMn3-xO4 nanoparticles contaminated with CoO phases because Co and Mn can occupy all cation sites and the impurity simulates typical products of oxide syntheses. We take advantage of the spin and oxidation state sensitive Kß1,3 peak obtained using XES and demonstrate that XES is a powerful and reliable technique for determining site occupation in ternary spinel systems. Comparison between the extended X-ray absorption fine structure (EXAFS) and XES techniques reveals that XES provides not only the site occupation information as EXAFS, but also additional information on the oxidation states of the cations at each site. We show that the error for EXAFS can be as high as 35% which makes the results obtained ambiguous for certain stoichiometries, whereas for XES, the error determined is consistently smaller than 10%. Thus, we conclude that XES is a superior and a far more accurate method than XAS in extracting cation site occupation in spinel crystal structures.

18.
Genes Dev ; 23(23): 2700-4, 2009 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-19903759

RESUMEN

While the global down-regulation of microRNAs (miRNAs) is a common feature of human tumors, its genetic basis is largely undefined. To explore this question, we analyzed the consequences of conditional Dicer1 mutation (Dicer1 "floxed" or Dicer1(fl)) on several mouse models of cancer. Here we show Dicer1 functions as a haploinsufficient tumor suppressor gene. Deletion of a single copy of Dicer1 in tumors from Dicer1(fl/+) animals led to reduced survival compared with controls. These tumors exhibited impaired miRNA processing but failed to lose the wild-type Dicer1 allele. Moreover, tumors from Dicer1(fl/fl) animals always maintained one functional Dicer1 allele. Consistent with selection against full loss of Dicer1 expression, enforced Dicer1 deletion caused inhibition of tumorigenesis. Analysis of human cancer genome copy number data reveals frequent deletion of DICER1. Importantly, however, the gene has not been reported to undergo homozygous deletion, suggesting that DICER1 is haploinsufficient in human cancer. These findings suggest Dicer1 may be an important haploinsufficient tumor suppressor gene and, furthermore, that other factors controlling miRNA biogenesis may also function in this manner.


Asunto(s)
Neoplasias Pulmonares/genética , Neoplasias Pulmonares/fisiopatología , Ribonucleasa III , Sarcoma/genética , Sarcoma/fisiopatología , Proteínas Supresoras de Tumor , Animales , Línea Celular Tumoral , Modelos Animales de Enfermedad , Eliminación de Gen , Humanos , Neoplasias Pulmonares/mortalidad , Ratones , Ratones Endogámicos C57BL , MicroARNs/metabolismo , Mutación/genética , Ribonucleasa III/genética , Ribonucleasa III/metabolismo , Sarcoma/mortalidad , Análisis de Supervivencia , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo
19.
J Neurosci ; 35(16): 6265-76, 2015 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-25904780

RESUMEN

Alzheimer's disease (AD) and familial Danish dementia (FDD) are degenerative neurological diseases characterized by amyloid pathology. Normal human sera contain IgG antibodies that specifically bind diverse preamyloid and amyloid proteins and have shown therapeutic potential in vitro and in vivo. We cloned one of these antibodies, 3H3, from memory B cells of a healthy individual using a hybridoma method. 3H3 is an affinity-matured IgG that binds a pan-amyloid epitope, recognizing both Aß and λ Ig light chain (LC) amyloids, which are associated with AD and primary amyloidosis, respectively. The pan-amyloid-binding properties of 3H3 were demonstrated using ELISA, immunohistochemical studies, and competition binding assays. Functional studies showed that 3H3 inhibits both Aß and LC amyloid formation in vitro and abrogates disruption of hippocampal synaptic plasticity by AD-patient-derived soluble Aß in vivo. A 3H3 single-chain variable fragment (scFv) retained the binding specificity of the 3H3 IgG and, when expressed in the brains of transgenic mice using an adeno-associated virus (AAV) vector, decreased parenchymal Aß amyloid deposition in TgCRND8 mice and ADan (Danish Amyloid) cerebral amyloid angiopathy in the mouse model of FDD. These data indicate that naturally occurring human IgGs can recognize a conformational, amyloid-specific epitope and have potent anti-amyloid activities, providing a rationale to test their potential as antibody therapeutics for diverse neurological and other amyloid diseases.


Asunto(s)
Péptidos beta-Amiloides/inmunología , Amiloide/metabolismo , Anticuerpos Monoclonales/inmunología , Inmunoglobulina G/inmunología , Amiloide/efectos de los fármacos , Animales , Anticuerpos Monoclonales/farmacología , Encéfalo/metabolismo , Catarata/inmunología , Ataxia Cerebelosa/inmunología , Angiopatía Amiloide Cerebral/inmunología , Sordera/inmunología , Demencia/inmunología , Humanos , Inmunoglobulina G/farmacología , Masculino , Ratones , Ratones Transgénicos , Ratas
20.
Am J Hum Biol ; 28(4): 587-90, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-26799235

RESUMEN

OBJECTIVES: This study investigated morning salivary cortisol concentration in relation to total body fat composition among community-dwelling Papua New Guinean adults. METHODS: In addition to demographic and anthropometric measurements, saliva was collected in a single morning from 478 residents in Eastern Highlands Province and Madang Province. RESULTS: After adjusting for age, region, and occupation, the morning salivary cortisol concentration was significantly negatively correlated with body mass index among men (B = -0.01, P < 0.05) and women (B = -0.013, P < 0.05), and waist circumference (B = -0.007, P < 0.05), waist-to-hip-ratio (B = -1.214, P < 0.05), and subscapular-to-triceps skinfold-thickness ratio (B = -0.045, P < 0.05) among men. Men with total or abdominal body fat mass known for elevated risk of non-communicable diseases displayed lower cortisol compared to men without such risk. CONCLUSIONS: Papua New Guinean adults with increased accumulation of body fat showed reduced cortisol concentration in morning saliva. Am. J. Hum. Biol. 28:587-590, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Tejido Adiposo/metabolismo , Hidrocortisona/metabolismo , Obesidad/metabolismo , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Papúa Nueva Guinea , Saliva/química , Factores de Tiempo , Adulto Joven
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