RESUMO
Adult neural stem cells (NSCs) reside in the dentate gyrus of the hippocampus, and their capacity to generate neurons and glia plays a role in learning and memory. In addition, neurodegenerative diseases are known to be caused by a loss of neurons and glial cells, resulting in a need to better understand stem cell fate commitment processes. We previously showed that NSC fate commitment toward a neuronal or glial lineage is strongly influenced by extracellular matrix stiffness, a property of elastic materials. However, tissues in vivo are not purely elastic and have varying degrees of viscous character. Relatively little is known about how the viscoelastic properties of the substrate impact NSC fate commitment. Here, we introduce a polyacrylamide-based cell culture platform that incorporates mismatched DNA oligonucleotide-based cross-links as well as covalent cross-links. This platform allows for tunable viscous stress relaxation properties via variation in the number of mismatched base pairs. We find that NSCs exhibit increased astrocytic differentiation as the degree of stress relaxation is increased. Furthermore, culturing NSCs on increasingly stress-relaxing substrates impacts cytoskeletal dynamics by decreasing intracellular actin flow rates and stimulating cyclic activation of the mechanosensitive protein RhoA. Additionally, inhibition of motor-clutch model components such as myosin II and focal adhesion kinase partially or completely reverts cells to lineage distributions observed on elastic substrates. Collectively, our results introduce a unique system for controlling matrix stress relaxation properties and offer insight into how NSCs integrate viscoelastic cues to direct fate commitment.
Assuntos
Diferenciação Celular , Células-Tronco Neurais , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/fisiologia , Animais , Astrócitos/citologia , Astrócitos/metabolismo , Astrócitos/fisiologia , Camundongos , Resinas Acrílicas/química , Proteína rhoA de Ligação ao GTP/metabolismo , Células Cultivadas , Neurônios/metabolismo , Neurônios/fisiologia , Neurônios/citologia , Matriz Extracelular/metabolismo , Estresse MecânicoRESUMO
During the intricate process by which cells give rise to tissues, embryonic and adult stem cells are exposed to diverse mechanical signals from the extracellular matrix (ECM) that influence their fate. Cells can sense these cues in part through dynamic generation of protrusions, modulated and controlled by cyclic activation of Rho GTPases. However, it remains unclear how extracellular mechanical signals regulate Rho GTPase activation dynamics and how such rapid, transient activation dynamics are integrated to yield long-term, irreversible cell fate decisions. Here, we report that ECM stiffness cues alter not only the magnitude but also the temporal frequency of RhoA and Cdc42 activation in adult neural stem cells (NSCs). Using optogenetics to control the frequency of RhoA and Cdc42 activation, we further demonstrate that these dynamics are functionally significant, where high- vs. low-frequency activation of RhoA and Cdc42 drives astrocytic vs. neuronal differentiation, respectively. In addition, high-frequency Rho GTPase activation induces sustained phosphorylation of the TGFß pathway effector SMAD1, which in turn drives the astrocytic differentiation. By contrast, under low-frequency Rho GTPase stimulation, cells fail to accumulate SMAD1 phosphorylation and instead undergo neurogenesis. Our findings reveal the temporal patterning of Rho GTPase signaling and the resulting accumulation of an SMAD1 signal as a critical mechanism through which ECM stiffness cues regulate NSC fate.
Assuntos
Células-Tronco Neurais , Proteínas rho de Ligação ao GTP , Proteínas rho de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Diferenciação Celular , Transdução de Sinais , Neurogênese , Células-Tronco Neurais/metabolismoRESUMO
BACKGROUND: Oil bodies or lipid droplets (LDs) in the cytosol are the subcellular storage compartments of seeds and the sites of lipid metabolism providing energy to the germinating seeds. Major LD-associated proteins are lipoxygenases, phospholipaseD, oleosins, TAG-lipases, steroleosins, caleosins and SEIPINs; involved in facilitating germination and enhancing peroxidation resulting in off-flavours. However, how natural selection is balancing contradictory processes in lipid-rich seeds remains evasive. The present study was aimed at the prediction of selection signatures among orthologous clades in major oilseeds and the correlation of selection effect with gene expression. RESULTS: The LD-associated genes from the major oil-bearing crops were analyzed to predict natural selection signatures in phylogenetically close-knit ortholog clusters to understand adaptive evolution. Positive selection was the major force driving the evolution and diversification of orthologs in a lineage-specific manner. Significant positive selection effects were found in 94 genes particularly in oleosin and TAG-lipases, purifying with excess of non-synonymous substitution in 44 genes while 35 genes were neutral to selection effects. No significant selection impact was noticed in Brassicaceae as against LOX genes of oil palm. A heavy load of deleterious mutations affecting selection signatures was detected in T-lineage oleosins and LOX genes of Arachis hypogaea. The T-lineage oleosin genes were involved in mainly anther, tapetum and anther wall morphogenesis. In Ricinus communis and Sesamum indicum > 85% of PLD genes were under selection whereas selection pressures were low in Brassica juncea and Helianthus annuus. Steroleosin, caleosin and SEIPINs with large roles in lipid droplet organization expressed mostly in seeds and were under considerable positive selection pressures. Expression divergence was evident among paralogs and homeologs with one gene attaining functional superiority compared to the other. The LOX gene Glyma.13g347500 associated with off-flavor was not expressed during germination, rather its paralog Glyma.13g347600 showed expression in Glycine max. PLD-α genes were expressed on all the tissues except the seed,δ genes in seed and meristem while ß and γ genes expressed in the leaf. CONCLUSIONS: The genes involved in seed germination and lipid metabolism were under strong positive selection, although species differences were discernable. The present study identifies suitable candidate genes enhancing seed oil content and germination wherein directional selection can become more fruitful.
Assuntos
Produtos Agrícolas , Evolução Molecular , Gotículas Lipídicas , Seleção Genética , Gotículas Lipídicas/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Óleos de Plantas/metabolismo , Sementes/genética , Sementes/metabolismo , Sementes/crescimento & desenvolvimento , Regulação da Expressão Gênica de PlantasRESUMO
To increase rice yields and feed billions of people, it is essential to enhance genetic gains. However, the development of new varieties is hindered by longer generation times and seasonal constraints. To address these limitations, a speed breeding facility has been established and a robust speed breeding protocol, SpeedFlower is developed that allows growing 4-5 generations of indica and/or japonica rice in a year. Our findings reveal that a high red-to-blue (2R > 1B) spectrum ratio, followed by green, yellow and far-red (FR) light, along with a 24-h long day (LD) photoperiod for the initial 15 days of the vegetative phase, facilitated early flowering. This is further enhanced by 10-h short day (SD) photoperiod in the later stage and day and night temperatures of 32/30 °C, along with 65% humidity facilitated early flowering ranging from 52 to 60 days at high light intensity (800 µmol m-2 s-1). Additionally, the use of prematurely harvested seeds and gibberellic acid treatment reduced the maturity duration by 50%. Further, SpeedFlower was validated on a diverse subset of 198 rice accessions from 3K RGP panel encompassing all 12 distinct groups of Oryza sativa L. classes. Our results confirmed that using SpeedFlower one generation can be achieved within 58-71 days resulting in 5.1-6.3 generations per year across the 12 sub-groups. This breakthrough enables us to enhance genetic gain, which could feed half of the world's population dependent on rice.
Assuntos
Oryza , Humanos , Oryza/genética , Melhoramento Vegetal , LuzRESUMO
Several new viral infections have emerged in the human population and establishing as global pandemics. With advancements in translation research, the scientific community has developed potential therapeutics to eradicate or control certain viral infections, such as smallpox and polio, responsible for billions of disabilities and deaths in the past. Unfortunately, some viral infections, such as dengue virus (DENV) and human immunodeficiency virus-1 (HIV-1), are still prevailing due to a lack of specific therapeutics, while new pathogenic viral strains or variants are emerging because of high genetic recombination or cross-species transmission. Consequently, to combat the emerging viral infections, bioinformatics-based potential strategies have been developed for viral characterization and developing new effective therapeutics for their eradication or management. This review attempts to provide a single platform for the available wide range of bioinformatics-based approaches, including bioinformatics methods for the identification and management of emerging or evolved viral strains, genome analysis concerning the pathogenicity and epidemiological analysis, computational methods for designing the viral therapeutics, and consolidated information in the form of databases against the known pathogenic viruses. This enriched review of the generally applicable viral informatics approaches aims to provide an overview of available resources capable of carrying out the desired task and may be utilized to expand additional strategies to improve the quality of translation viral informatics research.
Assuntos
Biologia Computacional , Viroses , Humanos , Pandemias , Viroses/tratamento farmacológico , Viroses/genéticaRESUMO
Under stress conditions, ribosome biogenesis is downregulated. This process requires that expression of ribosomal RNA, ribosomal protein, and ribosome biogenesis genes be controlled in a coordinated fashion. The mechanistic Target of Rapamycin Complex 1 (mTORC1) participates in sensing unfavorable conditions to effect the requisite change in gene expression. In Saccharomyces cerevisiae, downregulation of ribosomal protein genes involves dissociation of the activator Ifh1p in a process that depends on Utp22p, a protein that also functions in pre-rRNA processing. Ifh1p has a paralog, Crf1p, which was implicated in communicating mTORC1 inhibition and hence was perceived as a repressor. We focus here on two ribosomal biogenesis genes, encoding Utp22p and the high mobility group protein Hmo1p, both of which are required for communication of mTORC1 inhibition to target genes. Crf1p functions as an activator on these genes as evidenced by reduced mRNA abundance and RNA polymerase II occupancy in a crf1Δ strain. Inhibition of mTORC1 has distinct effects on expression of HMO1 and UTP22; for example, on UTP22, but not on HMO1, the presence of Crf1p promotes the stable depletion of Ifh1p. Our data suggest that Crf1p functions as a weak activator, and that it may be required to prevent re-binding of Ifh1p to some gene promoters after mTORC1 inhibition in situations when Ifh1p is available. We propose that the inclusion of genes encoding proteins required for mTORC1-mediated downregulation of ribosomal protein genes in the same regulatory circuit as the ribosomal protein genes serves to optimize transcriptional responses during mTORC1 inhibition.
Assuntos
Regulação Fúngica da Expressão Gênica , Alvo Mecanístico do Complexo 1 de Rapamicina , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Proteínas de Grupo de Alta Mobilidade/genética , Proteínas de Grupo de Alta Mobilidade/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , TransativadoresRESUMO
INTRODUCTION: The world is experiencing exponential growth in communication, especially wireless communication. Wireless connectivity has recently become a part of everyone's daily life. Recent developments in low-cost, low-power, and miniature devices contribute to a significant rise in radiofrequency-electromagnetic field (RF-EM) radiation exposure in our environment, raising concern over its effect on biological systems. The inconsistent and conflicting research results make it difficult to draw definite conclusions about how RF-EM radiation affects living things. OBJECTIVES: This study identified two micro-environments based on their level of exposure to cellular RF-EM radiation, one with significantly less exposure and another with very high exposure to RF-EM radiation. Emphasis is given to studying the metabolites in the urine samples of humans naturally exposed to these two different microenvironments to understand short-term metabolic dysregulations. METHODS: Untargeted 1H NMR spectroscopy was employed for metabolomics analyses to identify dysregulated metabolites. A total of 60 subjects were recruited with 5 ml urine samples each. These subjects were divided into two groups: one highly exposed to RF-EM (n = 30) and the other consisting of low-exposure populations (n = 30). RESULTS: The study found that the twenty-nine metabolites were dysregulated. Among them, 19 were downregulated, and 10 were upregulated. In particular, Glyoxylate and dicarboxylate and the TCA cycle metabolism pathway have been perturbed. The dysregulated metabolites were validated using the ROC curve analysis. CONCLUSION: Untargeted urine metabolomics was conducted to identify dysregulated metabolites linked to RF-EM radiation exposure. Preliminary findings suggest a connection between oxidative stress and gut microbiota imbalance. However, further research is needed to validate these biomarkers and understand the effects of RF-EM radiation on human health. Further research is needed with a diverse population.
Assuntos
Metaboloma , Metabolômica , Ondas de Rádio , Humanos , Masculino , Adulto , Metabolômica/métodos , Feminino , Ondas de Rádio/efeitos adversos , Metaboloma/efeitos da radiação , Pessoa de Meia-Idade , Campos Eletromagnéticos/efeitos adversos , Adulto JovemRESUMO
Extracellular signal-regulated kinase (Erk)-5 is a key mediator of endothelial cell homeostasis, and its inhibition causes loss of critical endothelial markers leading to endothelial dysfunction (ED). Circulating oxidized low-density lipoprotein (oxLDL) has been identified as an underlying cause of ED and atherosclerosis in metabolic disorders. Silymarin (Sym), a flavonolignan, possesses various pharmacological activities however its preventive mechanism in ED warrants further investigation. Here, we have examined the effects of Sym in regulating the expression of Erk-5 and ameliorating ED using in vitro and in vivo models. Primary human umbilical vein endothelial cells (pHUVECs) viability was measured by MTT assay; mRNA and protein expression by RT-qPCR and Western blotting; tube-formation assay was performed to examine endothelialness. In in-vivo experiments, normal chow-fed mice (control) or high-fat diet (HFD)-fed mice were administered Sym or Erk-5 inhibitor (BIX02189) and body weight, blood glucose, plasma-LDL, oxLDL levels, and expression of EC markers in the aorta were examined. Sym (5 µg/ml) maintained the viability and tube-formation ability of oxLDL exposed pHUVECs. Sym increased the expression of Erk-5, vWF, and eNOS and decreased ICAM-1 at transcription and translation levels in oxLDL-exposed pHUVECs. In HFD-fed mice, Sym reduced the body weight, blood glucose, LDL-cholesterol, and oxLDL levels, and increased the levels of vWF and eNOS along with Erk-5 and decreased the level of ICAM-1 in the aorta. These data suggest that Sym could be a potent anti-atherosclerotic agent that could elevate Erk-5 level in the ECs and prevent ED caused by oxidized LDL during HFD-induced obesity in mice.
Assuntos
Aterosclerose , Silimarina , Humanos , Animais , Camundongos , Molécula 1 de Adesão Intercelular , Transdução de Sinais , Células Cultivadas , Silimarina/efeitos adversos , Glicemia , Fator de von Willebrand , Lipoproteínas LDL/toxicidade , Lipoproteínas LDL/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Aterosclerose/tratamento farmacológico , Aterosclerose/prevenção & controle , Aterosclerose/induzido quimicamente , Peso CorporalRESUMO
Protein brushes not only play a key role in the functionality of neurofilaments but also have wide applications in biomedical materials. Here, we investigate the effect of ionic strength on the morphology of protein brushes using continuous-space self-consistent field theory. A coarse-grained multiblock charged macromolecular model is developed to capture the chemical identity of amino acid sequences. For neurofilament heavy (NFH) brushes at pH 2.4, we predict three morphological regimes: swollen brushes, condensed brushes, and coexisting brushes, which consist of both a dense inner layer and a diffuse outer layer. The brush height predicted by our theory is in good agreement with the experimental data for a wide range of ionic strengths. The dramatic height decrease is a result of the electrostatic screening-induced transition from the overlapping state to the isolated state of the coexisting brushes. We also studied the evolution of the scattering and mechanical responses accompanying the morphological change. The oscillation in the reflectivity spectra characterizes the existence and microstructure of the inner condensed layer, whereas the shoulder in the force spectra signifies a swollen morphology.
Assuntos
Filamentos Intermediários , Proteínas de Neurofilamentos , Proteínas de Neurofilamentos/química , Substâncias Macromoleculares/química , Sequência de Aminoácidos , Concentração OsmolarRESUMO
Aging, a natural biological process, presents challenges in maintaining physiological well-being and is associated with increased vulnerability to diseases. Addressing aging mechanisms is crucial for developing effective preventive and therapeutic strategies against age-related ailments. Rosmarinus officinalis L. is a medicinal herb widely used in traditional medicine, containing diverse bioactive compounds that have been studied for their antioxidant and anti-inflammatory properties, which are associated with potential health benefits. Using network pharmacology, this study investigates the anti-aging function and underlying mechanisms of R. officinalis. Through network pharmacology analysis, the top 10 hub genes were identified, including TNF, CTNNB1, JUN, MTOR, SIRT1, and others associated with the anti-aging effects. This analysis revealed a comprehensive network of interactions, providing a holistic perspective on the multi-target mechanism underlying Rosemary's anti-aging properties. GO and KEGG pathway enrichment analysis revealed the relevant biological processes, molecular functions, and cellular components involved in treating aging-related conditions. KEGG pathway analysis shows that anti-aging targets of R. officinalis involved endocrine resistance, pathways in cancer, and relaxin signaling pathways, among others, indicating multifaceted mechanisms. Genes like MAPK1, MMP9, and JUN emerged as significant players. These findings enhance our understanding of R. officinalis's potential in mitigating aging-related disorders through multi-target effects on various biological processes and pathways. Such approaches may reduce the risk of failure in single-target and symptom-based drug discovery and therapy.
RESUMO
We study the influence of confinement on the dynamics of translocation of a linear polymer chain in a good solvent through a cone-shaped pore. Using the Langevin dynamics simulations, we calculate both the first attempt time and translocation time as a function of the position of the back wall and apex angle α. As the in vivo confining environment is inherently dynamic, we extended the present study to explore the consequences of a periodically driven back wall and apex angles on the translocation dynamics. Our findings reveal that the translocation time initially decreases as the driving frequency increases, but increases after a certain frequency. The frequency at which the translocation time is found to be minimum is referred to as the resonance activation. Analyzing the distribution of translocation times around this frequency renders interesting information about the translocation process. We further explore the translocation dynamics by calculating the residence time of individual monomers, shedding light on the microscopic aspects of the process.
RESUMO
Bacterial DNA gyrase and topoisomerase IV inhibition has emerged as a promising strategy for the cure of infections caused by antibiotic-resistant bacteria. The Novel Bacterial Topoisomerase Inhibitors (NBTIs) bind to a different site from that of the quinolones with novel mechanism of action. This evades the existing target-mediated bacterial resistance associated with quinolones. This article presents our efforts to identify in vitro potent and broad-spectrum antibacterial agent 4l.
Assuntos
Antibacterianos , Testes de Sensibilidade Microbiana , Piperidinas , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Piperidinas/química , Piperidinas/farmacologia , Piperidinas/síntese química , Relação Estrutura-Atividade , Inibidores da Topoisomerase/farmacologia , Inibidores da Topoisomerase/química , Inibidores da Topoisomerase/síntese química , DNA Girase/metabolismo , Inibidores da Topoisomerase II/farmacologia , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/síntese química , DNA Topoisomerase IV/antagonistas & inibidores , DNA Topoisomerase IV/metabolismo , Estrutura Molecular , Descoberta de Drogas , Relação Dose-Resposta a Droga , HumanosRESUMO
INTRODUCTION: Acute pancreatitis poses a significant health risk due to the potential for pancreatic necrosis and multi-organ failure. Fluid resuscitation has demonstrated positive effects; however, consensus on the ideal intravenous fluid type and infusion rate for optimal patient outcomes remains elusive. METHODS: A comprehensive literature search was conducted using PubMed, Embase, the Cochrane Library, Scopus, and Google Scholar for studies published between 2005 and January 2023. Reference lists of potential studies were manually searched to identify additional relevant articles. Randomized controlled trials and retrospective studies comparing high (≥ 20 ml/kg/h), moderate (≥ 10 to < 20 ml/kg/h), and low (5 to < 10 ml/kg/h) fluid therapy in acute pancreatitis were considered. RESULTS: Twelve studies met our inclusion criteria. Results indicated improved clinical outcomes with low versus moderate fluid therapy (OR = 0.73; 95% CI [0.13, 4.03]; p = 0.71) but higher mortality rates with low compared to moderate (OR = 0.80; 95% CI [0.37, 1.70]; p = 0.55), moderate compared to high (OR = 0.58; 95% CI [0.41, 0.81], p = 0.001), and low compared to high fluids (OR = 0.42; 95% CI [0.16, 1.10]; P = 0.08). Systematic complications improved with moderate versus low fluid therapy (OR = 1.22; 95% CI [0.84, 1.78]; p = 0.29), but no difference was found between moderate and high fluid therapy (OR = 0.59; 95% CI [0.41, 0.86]; p = 0.006). DISCUSSION: This meta-analysis revealed differences in the clinical outcomes of patients with AP receiving low, moderate, and high fluid resuscitation. Low fluid infusion demonstrated better clinical outcomes but higher mortality, systemic complications, and SIRS persistence than moderate or high fluid therapy. Early fluid administration yielded better results than rapid fluid resuscitation.
Assuntos
Hidratação , Pancreatite , Humanos , Hidratação/métodos , Pancreatite/terapia , Pancreatite/mortalidade , Ressuscitação/métodos , Resultado do Tratamento , Doença Aguda , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
A photoluminescent terbium (III)-based Metal Organic Framework (MOF) was synthesized at room temperature by layer diffusion method utilizing mixed carboxylate linkers (4,4'-oxybis(benzoic acid) and benzene-1,3,5 tricarboxylic acid). Synthesized MOF has crystalline nature and rod-shaped morphology and is thermally stable up to 455 °C. The fluorescence emission spectra and theoretical results revealed that carboxylate linkers functioned as sensitizers for Tb(III) photoluminescence which resulted in four distinct emission peaks at 495, 547, 584, and 621 nm corresponding to the transitions 5D4 â 7F6, 5D4 â 7F5, 5D4 â 7F4, and 5D4 â 7F3. Using synthesized MOF as fluorescent probe, hydroquinone was detected in aqueous medium with a detection limit of 0.048 µM, remarkable recovery (95.6-101.1%), and relative standard deviation less than 2.25%. The quenching phenomenon may be ascribed to electron transfer from synthesized probe to oxidized hydroquinone via carboxylic groups on the surface of MOF, which is further supported by photo-induced electron transfer mechanism. This study introduces a cheaper, faster, and more accurate method for hydroquinone detection.
RESUMO
BACKGROUND AND AIM: Celiac disease (CeD) has now become a global disease with a worldwide prevalence of 0.67%. Despite being a common disease, CeD is often not diagnosed and there is a significant delay in its diagnosis. We reviewed the impact of the delay in the diagnosis on the severity of manifestations of CeD. METHODS: We reviewed clinical records of 726 consecutive patients with CeD from the Celiac Clinic database and the National Celiac Disease Consortium database. We extracted specific data including the demographics, symptoms at presentation, time of onset of symptoms, time to diagnosis from the onset of the symptoms, and relevant clinical data including fold-rise in anti-tissue transglutaminase antibody (IgA anti-tTG Ab) and severity of villous and crypt abnormalities as assessed using modified Marsh classification. RESULTS: The median duration between the onset of symptoms and the diagnosis of CeD was 27 months (interquartile range 12-60 months). A longer delay in the diagnosis of CeD from the onset of symptoms was associated with lower height for age, lower hemoglobin, higher fold rise in IgA Anti tTG titers, and higher severity of villous and crypt abnormalities. About 18% of patients presented with predominantly non-gastrointestinal complaints and had a longer delay in the diagnosis of CeD. CONCLUSIONS: There is a significant delay in the diagnosis of CeD since the onset of its symptoms. The severity of celiac disease increases with increasing delay in its diagnosis. There is a need to keep a low threshold for the diagnosis of CeD in appropriate clinical settings.
Assuntos
Doença Celíaca , Humanos , Doença Celíaca/diagnóstico , Doença Celíaca/epidemiologia , Doença Celíaca/complicações , Transglutaminases , Hemoglobinas , Imunoglobulina A , Atrofia , AutoanticorposRESUMO
BACKGROUND AND AIM: While European Society of Pediatric Gastroenterology Hepatology and Nutrition advocates a no-biopsy pathway for the diagnosis of celiac disease (CeD) in children if IgA anti-tissue transglutaminase antibody (anti-tTG ab) titer is ≥10-fold upper limit of normal (ULN) and have a positive IgA anti-endomysial antibody (EMA); the data for anti-tTG Ab titer-based diagnosis of CeD in adults is still emerging. We planned to validate if IgA anti-tTG Ab titer ≥10-fold predicts villous abnormalities of modified Marsh grade ≥2 in Asian adult patients with CeD. METHODS: We recruited 937 adult patients with positive anti-tTG Ab from two databases, including AIIMS Celiac Clinic and Indian National Biorepository. The diagnosis of definite CeD was made on the basis of a positive anti-tTG Ab and the presence of villous abnormalities of modified Marsh grade ≥2. RESULTS: Of 937 adult patients with positive anti-tTG Ab, 889 (91.2%) showed villous abnormalities of modified Marsh grade ≥2. Only 47.6% of 889 adults with CeD had anti- tTG Ab titers of ≥10-fold. The positive predictive value (PPV) and specificity of anti tTG Ab titer ≥10-fold for predicting modified Marsh grade ≥2 were 99.8% and 98%, respectively. At anti-tTG Ab titer ≥11-fold, specificity and PPV were 100% for predicting villous abnormalities of modified Marsh grade ≥2. CONCLUSIONS: Approximately 50% of adults with CeD may benefit from the no biopsy pathway, reducing the health burden and risks of gastroscopy/anesthesia.
Assuntos
Doença Celíaca , Adulto , Humanos , Autoanticorpos , Doença Celíaca/patologia , Proteínas de Ligação ao GTP , Imunoglobulina A , Proteína 2 Glutamina gama-Glutamiltransferase , Estudos Retrospectivos , Sensibilidade e Especificidade , TransglutaminasesRESUMO
In this work, the dielectric response of polycrystalline Ba3CoSb2O9 was studied as a function of temperature (30 to 900 °C) and frequency (10 Hz to 10 MHz). The triple perovskite Ba3CoSb2O9 was successfully synthesized and characterized for structural and dielectric properties. The Rietveld analysis of the X-ray diffractogram confirms the formation of a hexagonal phase with P63/mmc symmetry. This centrosymmetric 3(BaCo1/3Sb2/3O3) perovskite shows structural similarity to a prototypical non-centrosymmetric relaxor ferroelectric, PbMg1/3Nb2/3O3. The dielectric constant, ε', follows a non-Debye Cole-Cole relation and exhibits anomalous responses such as: (a) a thermally activated colossal dielectric constant (>105) and (b) a highly dispersive peak maximum (523-853 K). The real part of ac conductivity, σ', also shows a change of approximately 6 orders in magnitude (10-8 to 10-2 S m-1). Validation of Jonscher's law and impedance (Nyquist plot) and modulus (M'') analyses indicate that hopping polarization is the predominant thermally activated mechanism. Moreover, the large value of ε' and its dispersion were found to be highly correlated with the underlying crystal structure and were attributed to the local ionic site ordering. The study suggests that the anomalous dielectric dispersion must have an intrinsic origin.
RESUMO
We experimentally probe the microscopic variations in a model polymer-nanoparticle (NP) binary mixture (mixture of polybutadiene and clay nanoplatelets) across a thermal evolution path for which Tevolution > Tg(polymer). The evolution of the NP dispersion, NP crystallinity, polymer chain-NP interface, and nature of polymer chain-NP interaction are mapped for a spectrum of temperatures and NP concentrations constrained by experiments. Multiple pieces of evidence indicate that thermal evolution does not influence the nature of interparticle dispersion and is also independent of NP concentration in the binary mixture. However, the NP crystalline order significantly reduces across the thermal evolution path. Thermal evolution induces a transition of a sharp polymer chain-NP interface to a diffuse interfacial layer. In contrast, an already diffuse polymer-NP interface existing in the binary mixture due to particle crowding at high NP concentrations undergoes no significant change in its nature across the evolution path. At all particle concentrations, thermal evolution changes the dominant interaction from polymer chain-polymer chain to polymer chain-NP. These insights aid in explaining the molecular origins of unique and anomalous behaviors shown by polymer-nanoparticle binary mixtures while undergoing thermal evolution.
RESUMO
Hyperpolarization by dissolution dynamic nuclear polarization (dDNP) provides the opportunity to dramatically increase the weak nuclear magnetic resonance (NMR) signal of liquid molecular targets using the high polarization of electron radicals. Unfortunately, the solution-state hyperpolarization can only be accessed once since freezing and melting of the hyperpolarized sample happen in an irreversible fashion. A way to expand the application horizon of dDNP can therefore be to find a recyclable DNP alternative. To pursue this ambitious goal, we recently introduced the concept of recyclable hyperpolarized flow (HypFlow) DNP where hyperpolarization happens in porous hyperpolarizing solids placed in a compact benchtop DNP polarizer at a magnetic field of 1 T and a temperature of 77 K. Here we aim to optimize the radical concentrations immobilized in hyperpolarizing solids with the objective of generating as much polarization as possible in a timeframe (<1 s) compatible with future recyclable DNP applications. To do so, the solid-state DNP enhancement factors, build-up rates and DNP spectra of different hyperpolarizing solids containing various nitroxide radical loadings (20-74 µmol cm-3) are compared against the DNP performance of varying nitroxide concentrations (10-100 mM) solvated in a glassy frozen solution. We demonstrate that in <1 s, polarization enhancement goes up to 56 and 102 with surface-bound and solvated radicals, respectively, under the optimized conditions. For the range of nitroxide concentrations used cross effect DNP seems to be the dominant mechanism under benchtop conditions. This was deduced from the electron paramagnetic resonance (EPR) lineshape of TEMPOL investigated using Q-band EPR measurements.
RESUMO
Histone deacetylases (HDACs) have been identified as promising targets for anticancer treatment. The study demonstrates virtual screening, molecular docking, and synthesis of 4-(2-aminoethyl) phenol derivatives as HDAC inhibitors. The virtual screening and molecular docking analysis led to the identification of 10 representative compounds, which were evaluated based on their drug-like properties. The results demonstrated that these compounds effectively interacted with the active site pocket of HDAC 3 through π-stacking, Zn2+ coordination, hydrogen bonding, and hydrophobic interactions with catalytic residues. Furthermore, a series of 4-(2-aminoethyl) phenol derivatives were synthesized, and their HDAC inhibitory activity was evaluated. Compounds 18 and 20 showed significant HDAC inhibitory activity of 64.94 ± 1.17% and 52.45 ± 1.45%, respectively, compared to the solvent control. The promising results of this study encourage further research on 4-(2-aminoethyl) phenol derivatives and may provide significant insight into the design of novel small molecule HDAC inhibitors to fight against target-specific malignancies of chronic obstructive pulmonary disease and nonsmall cell lung cancer in the future.