Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 105
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Hum Brain Mapp ; 41(12): 3198-3211, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304267

RESUMO

White matter (WM) fiber bundles change dynamically with age. These changes could be driven by alterations in axonal diameter, axonal density, and myelin content. In this study, we applied a novel fixel-based analysis (FBA) framework to examine these changes throughout the adult lifespan. Using diffusion-weighted images from a cohort of 293 healthy volunteers (89 males/204 females) from ages 21 to 86 years old, we performed FBA to analyze age-related changes in microscopic fiber density (FD) and macroscopic fiber morphology (fiber cross section [FC]). Our results showed significant and widespread age-related alterations in FD and FC across the whole brain. Interestingly, some fiber bundles such as the anterior thalamic radiation, corpus callosum, and superior longitudinal fasciculus only showed significant negative relationship with age in FD values, but not in FC. On the other hand, some segments of the cerebello-thalamo-cortical pathway only showed significant negative relationship with age in FC, but not in FD. Analysis at the tract-level also showed that major fiber tract groups predominantly distributed in the frontal lobe (cingulum, forceps minor) exhibited greater vulnerability to the aging process than the others. Differences in FC and the combined measure of FD and cross section values observed between sexes were mostly driven by differences in brain sizes although male participants tended to exhibit steeper negative linear relationship with age in FD as compared to female participants. Overall, these findings provide further insights into the structural changes the brain's WM undergoes due to the aging process.


Assuntos
Envelhecimento/fisiologia , Imagem de Difusão por Ressonância Magnética , Desenvolvimento Humano/fisiologia , Fibras Nervosas Mielinizadas/fisiologia , Substância Branca/anatomia & histologia , Substância Branca/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vias Neurais/anatomia & histologia , Vias Neurais/diagnóstico por imagem , Fatores Sexuais , Substância Branca/diagnóstico por imagem , Adulto Jovem
2.
Aging Ment Health ; 24(9): 1496-1504, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-30990085

RESUMO

Objective: Performance-based evaluation of executive function by using real-world daily living activities is an important area of study. This approach has been used extensively in evaluating patients after stroke or traumatic brain injury and patients with schizophrenia. Most important is the fact that until now, there has been no validated performance-based evaluation of executive function in people with dementia.Methods: To address that knowledge gap, this study recruited 80 patients diagnosed with dementia and 80 demographically matched healthy controls. The participants were administered tests for evaluating their performance-based executive function (Chinese Multiple Errands Test), their instrumental activities of daily living (Lawton Instrumental Activities of Daily Living Scale, Chinese Version), and their functional disability (Chinese Version of the Disability Assessment for Dementia), along with a cognitive screening test (Montreal Cognitive Assessment, Hong Kong Version) and a neuropsychological test of executive function (Trail-making Test).Results: The Chinese Multiple Errands Test demonstrated excellent inter-rater reliability, test-retest reliability and high internal consistency. Results revealed that the healthy controls out-performed the dementia patients in the performance-based executive function and cognitive screening, but not in the instrumental activities of daily living tests. Additionally, the performance efficiency scores of the older adults with dementia on the Chinese Multiple Errands Test correlated significantly with their performance results on the neuropsychological test of executive function and on the tests of functional disability and cognitive function.Conclusion: Our results indicated that the Chinese Multiple Errands Test is a reliable and valid instrument for assessing executive function in Chinese older people with dementia.


Assuntos
Demência , Função Executiva , Atividades Cotidianas , Idoso , Hong Kong , Humanos , Testes Neuropsicológicos , Reprodutibilidade dos Testes
3.
Nat Methods ; 12(7): 657-660, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26005812

RESUMO

We present a robot that enables high-content studies of alert adult Drosophila by combining operations including gentle picking; translations and rotations; characterizations of fly phenotypes and behaviors; microdissection; or release. To illustrate, we assessed fly morphology, tracked odor-evoked locomotion, sorted flies by sex, and dissected the cuticle to image neural activity. The robot's tireless capacity for precise manipulations enables a scalable platform for screening flies' complex attributes and behavioral patterns.


Assuntos
Drosophila melanogaster/fisiologia , Ensaios de Triagem em Larga Escala , Robótica , Animais , Comportamento Animal , Fenômenos Biomecânicos , Drosophila melanogaster/anatomia & histologia , Feminino , Masculino , Fenótipo , Rotação
4.
Hum Genomics ; 11(1): 35, 2017 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-29268782

RESUMO

BACKGROUND: HSF1 (heat shock factor 1) is a transcription factor that is found to facilitate malignant cancer development and proliferation. In cancer cells, HSF1 mediates a set of genes distinct from heat shock that contributes to malignancy. This set of genes is known as the HSF1 Cancer Signature genes or simply HSF1-CanSig genes. HSF1-CanSig genes function and operate differently than typical cancer-causing genes, yet it is involved in fundamental oncogenic processes. RESULTS: By utilizing expression data from 9241 cancer patients, we identified that human chromosome 8q21-24 is a location hotspot for the most frequently overexpressed HSF1-CanSig genes. Intriguingly, the strength of the HSF1 cancer program correlates with the number of overexpressed HSF1-CanSig genes in 8q, illuminating the essential role of HSF1 in mediating gene expression in different cancers. Chromosome 8q21-24 is found under selective pressure in preserving gene order as it exhibits strong synteny among human, mouse, rat, and bovine, although the biological significance remains unknown. Statistical modeling, hierarchical clustering, and gene ontology-based pathway analyses indicate crosstalk between HSF1-mediated responses and pre-mRNA 3' processing in cancers. CONCLUSIONS: Our results confirm the unique role of chromosome 8q mediated by the master regulator HSF1 in cancer cases. Additionally, this study highlights the connection between cellular processes triggered by HSF1 and pre-mRNA 3' processing in cancers.


Assuntos
Biomarcadores Tumorais/genética , Cromossomos Humanos Par 8 , Regulação Neoplásica da Expressão Gênica , Fatores de Transcrição de Choque Térmico/genética , Neoplasias/genética , Animais , Bovinos , Redes Reguladoras de Genes , Genoma Humano , Fatores de Transcrição de Choque Térmico/metabolismo , Humanos , Camundongos , Neoplasias/metabolismo , Neoplasias/patologia , Regiões Promotoras Genéticas , Processamento Pós-Transcricional do RNA , Ratos , Células Tumorais Cultivadas
5.
BMC Genomics ; 18(1): 749, 2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-28938868

RESUMO

BACKGROUND: A genomic signal track is a set of genomic intervals associated with values of various types, such as measurements from high-throughput experiments. Analysis of signal tracks requires complex computational methods, which often make the analysts focus too much on the detailed computational steps rather than on their biological questions. RESULTS: Here we propose Signal Track Query Language (STQL) for simple analysis of signal tracks. It is a Structured Query Language (SQL)-like declarative language, which means one only specifies what computations need to be done but not how these computations are to be carried out. STQL provides a rich set of constructs for manipulating genomic intervals and their values. To run STQL queries, we have developed the Signal Track Analytical Research Tool (START, http://yiplab.cse.cuhk.edu.hk/start/ ), a system that includes a Web-based user interface and a back-end execution system. The user interface helps users select data from our database of around 10,000 commonly-used public signal tracks, manage their own tracks, and construct, store and share STQL queries. The back-end system automatically translates STQL queries into optimized low-level programs and runs them on a computer cluster in parallel. We use STQL to perform 14 representative analytical tasks. By repeating these analyses using bedtools, Galaxy and custom Python scripts, we show that the STQL solution is usually the simplest, and the parallel execution achieves significant speed-up with large data files. Finally, we describe how a biologist with minimal formal training in computer programming self-learned STQL to analyze DNA methylation data we produced from 60 pairs of hepatocellular carcinoma (HCC) samples. CONCLUSIONS: Overall, STQL and START provide a generic way for analyzing a large number of genomic signal tracks in parallel easily.


Assuntos
Genômica/métodos , Linguagens de Programação , Carcinoma Hepatocelular/genética , Humanos , Neoplasias Hepáticas/genética
6.
Annu Rev Neurosci ; 32: 435-506, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19555292

RESUMO

Since the work of Golgi and Cajal, light microscopy has remained a key tool for neuroscientists to observe cellular properties. Ongoing advances have enabled new experimental capabilities using light to inspect the nervous system across multiple spatial scales, including ultrastructural scales finer than the optical diffraction limit. Other progress permits functional imaging at faster speeds, at greater depths in brain tissue, and over larger tissue volumes than previously possible. Portable, miniaturized fluorescence microscopes now allow brain imaging in freely behaving mice. Complementary progress on animal preparations has enabled imaging in head-restrained behaving animals, as well as time-lapse microscopy studies in the brains of live subjects. Mouse genetic approaches permit mosaic and inducible fluorescence-labeling strategies, whereas intrinsic contrast mechanisms allow in vivo imaging of animals and humans without use of exogenous markers. This review surveys such advances and highlights emerging capabilities of particular interest to neuroscientists.


Assuntos
Microscopia/instrumentação , Microscopia/métodos , Sistema Nervoso/citologia , Neurônios/citologia , Neurociências/instrumentação , Neurociências/métodos , Animais , Humanos , Citometria por Imagem/instrumentação , Citometria por Imagem/métodos , Citometria por Imagem/tendências , Camundongos , Camundongos Transgênicos , Microscopia/tendências , Microscopia Confocal/instrumentação , Microscopia Confocal/métodos , Microscopia Confocal/tendências , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Microscopia de Fluorescência/tendências , Biologia Molecular/instrumentação , Biologia Molecular/métodos , Biologia Molecular/tendências , Neurônios/fisiologia , Neurociências/tendências
8.
Biol Reprod ; 97(4): 627-635, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29025046

RESUMO

Low protein (LP) diet during pregnancy leads to reduced plasma insulin levels in rodents, but the underlying mechanisms remain unclear. Glucose is the primary insulin secretagogue, and enhanced glucose-stimulated insulin secretion (GSIS) in beta cells contributes to compensation for insulin resistance and maintenance of glucose homeostasis during pregnancy. In this study, we hypothesized that plasma insulin levels in pregnant rats fed LP diet are reduced due to disrupted GSIS of pancreatic islets. We first confirmed reduced plasma insulin levels, then investigated in vivo insulin secretion by glucose tolerance test and ex vivo GSIS of pancreatic islets in the presence of glucose at different doses, and KCl, glibenclamide, and L-arginine. Main findings include (1) plasma insulin levels were unaltered on day 10, but significantly reduced on days 14-22 of pregnancy in rats fed LP diet compared to those of control (CT) rats; (2) insulin sensitivity was unchanged, but glucose intolerance was more severe in pregnant rats fed LP diet; (3) GSIS in pancreatic islets was lower in LP rats compared to CT rats in the presence of glucose, KCl, and glibenclamide, and the response to L-arginine was abolished in LP rats; and (4) the total insulin content in pancreatic islets and expression of Ins2 were reduced in LP rats, but expression of Gcg was unaltered. These studies demonstrate that decreased GSIS in beta cells of LP rats contributes to reduced plasma insulin levels, which may lead to placental and fetal growth restriction and programs hypertension and other metabolic diseases in offspring.


Assuntos
Dieta com Restrição de Proteínas , Proteínas Alimentares/farmacologia , Insulina/metabolismo , Animais , Arginina/farmacologia , Glicemia/efeitos dos fármacos , Proteínas Alimentares/administração & dosagem , Feminino , Glucose/metabolismo , Intolerância à Glucose , Glibureto/farmacologia , Resistência à Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Cloreto de Potássio/farmacologia , Gravidez , Deficiência de Proteína/metabolismo , Ratos , Ratos Wistar
10.
Immunol Cell Biol ; 94(9): 861-874, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27192936

RESUMO

The purple sea urchin (Strongylocentrotus purpuratus) genome sequence contains a complex repertoire of genes encoding innate immune recognition proteins and homologs of important vertebrate immune regulatory factors. To characterize how this immune system is deployed within an experimentally tractable, intact animal, we investigate the immune capability of the larval stage. Sea urchin embryos and larvae are morphologically simple and transparent, providing an organism-wide model to view immune response at cellular resolution. Here we present evidence for immune function in five mesenchymal cell types based on morphology, behavior and gene expression. Two cell types are phagocytic; the others interact at sites of microbial detection or injury. We characterize immune-associated gene markers for three cell types, including a perforin-like molecule, a scavenger receptor, a complement-like thioester-containing protein and the echinoderm-specific immune response factor 185/333. We elicit larval immune responses by (1) bacterial injection into the blastocoel and (2) seawater exposure to the marine bacterium Vibrio diazotrophicus to perturb immune state in the gut. Exposure at the epithelium induces a strong response in which pigment cells (one type of immune cell) migrate from the ectoderm to interact with the gut epithelium. Bacteria that accumulate in the gut later invade the blastocoel, where they are cleared by phagocytic and granular immune cells. The complexity of this coordinated, dynamic inflammatory program within the simple larval morphology provides a system in which to characterize processes that direct both aspects of the echinoderm-specific immune response as well as those that are shared with other deuterostomes, including vertebrates.


Assuntos
Microbioma Gastrointestinal/imunologia , Imunidade Celular , Larva/imunologia , Larva/microbiologia , Strongylocentrotus purpuratus/imunologia , Strongylocentrotus purpuratus/microbiologia , Animais , Comunicação Celular/genética , Epitélio/imunologia , Regulação da Expressão Gênica , Imunidade Celular/genética , Larva/citologia , Larva/genética , Modelos Imunológicos , Água do Mar , Strongylocentrotus purpuratus/citologia , Strongylocentrotus purpuratus/genética , Transcrição Gênica
11.
Proc Natl Acad Sci U S A ; 110(46): 18374-9, 2013 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-24167298

RESUMO

Intravital microscopy is a key means of monitoring cellular function in live organisms, but surgical preparation of a live animal for microscopy often is time-consuming, requires considerable skill, and limits experimental throughput. Here we introduce a spatially precise (<1-µm edge precision), high-speed (<1 s), largely automated, and economical protocol for microsurgical preparation of live animals for optical imaging. Using a 193-nm pulsed excimer laser and the fruit fly as a model, we created observation windows (12- to 350-µm diameters) in the exoskeleton. Through these windows we used two-photon microscopy to image odor-evoked Ca(2+) signaling in projection neuron dendrites of the antennal lobe and Kenyon cells of the mushroom body. The impact of a laser-cut window on fly health appears to be substantially less than that of conventional manual dissection, for our imaging durations of up to 18 h were ∼5-20 times longer than prior in vivo microscopy studies of hand-dissected flies. This improvement will facilitate studies of numerous questions in neuroscience, such as those regarding neuronal plasticity or learning and memory. As a control, we used phototaxis as an exemplary complex behavior in flies and found that laser microsurgery is sufficiently gentle to leave it intact. To demonstrate that our techniques are applicable to other species, we created microsurgical openings in nematodes, ants, and the mouse cranium. In conjunction with emerging robotic methods for handling and mounting flies or other small organisms, our rapid, precisely controllable, and highly repeatable microsurgical techniques should enable automated, high-throughput preparation of live animals for optical experimentation.


Assuntos
Encéfalo/cirurgia , Drosophila melanogaster/fisiologia , Lasers , Microcirurgia/métodos , Fenômenos Fisiológicos do Sistema Nervoso , Imagem Óptica/métodos , Animais , Formigas , Encéfalo/fisiologia , Cálcio/metabolismo , Camundongos , Nematoides , Imagem com Lapso de Tempo/métodos
12.
Dev Biol ; 382(1): 280-92, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23792116

RESUMO

Although vertebrate hematopoiesis is the focus of intense study, immunocyte development is well-characterized in only a few invertebrate groups. The sea urchin embryo provides a morphologically simple model for immune cell development in an organism that is phylogenetically allied to vertebrates. Larval immunocytes, including pigment cells and several blastocoelar cell subtypes, emerge from a population of non-skeletal mesodermal (NSM) precursors that is specified at the blastula stage. This ring of cells is first partitioned into oral and aboral fields with distinct blastocoelar and pigment cell gene regulatory programs. The oral field is subsequently specified into several distinct immune and non-immune cell types during gastrulation. Here we characterize the oral NSM expression and downstream function of two homologs of key vertebrate hematopoietic transcription factors: SpGatac, an ortholog of vertebrate Gata-1/2/3 and SpScl, an ortholog of Scl/Tal-2/Lyl-1. Perturbation of SpGatac affects blastocoelar cell migration at gastrulation and later expression of immune effector genes, whereas interference with SpScl function disrupts segregation of pigment and blastocoelar cell precursors. Homologs of several transcription regulators that interact with Gata-1/2/3 and Scl factors in vertebrate hematopoiesis are also co-expressed in the oral NSM, including SpE-protein, the sea urchin homolog of vertebrate E2A/HEB/E2-2 and SpLmo2, an ortholog of a dedicated cofactor of the Scl-GATA transcription complex. Regulatory analysis of SpGatac indicates that oral NSM identity is directly suppressed in presumptive pigment cells by the transcription factor SpGcm. These findings provide part of a comparative basis to understand the evolutionary origins and regulatory biology of deuterostome immune cell differentiation in the context of a tractable gene regulatory network model.


Assuntos
Evolução Molecular , Fatores de Transcrição GATA/metabolismo , Sistema Imunitário/citologia , Sistema Imunitário/metabolismo , Homologia de Sequência de Aminoácidos , Strongylocentrotus purpuratus/embriologia , Animais , Animais Geneticamente Modificados , Padronização Corporal/genética , Diferenciação Celular , Embrião não Mamífero/citologia , Embrião não Mamífero/metabolismo , Fatores de Transcrição GATA/genética , Regulação da Expressão Gênica no Desenvolvimento , Larva/citologia , Mesoderma/citologia , Mesoderma/metabolismo , Pigmentação , Strongylocentrotus purpuratus/genética , Transcrição Gênica
13.
BMC Genomics ; 15: 886, 2014 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-25306238

RESUMO

BACKGROUND: High-throughput experimental methods have fostered the systematic detection of millions of genetic variants from any human genome. To help explore the potential biological implications of these genetic variants, software tools have been previously developed for integrating various types of information about these genomic regions from multiple data sources. Most of these tools were designed either for studying a small number of variants at a time, or for local execution on powerful machines. RESULTS: To make exploration of whole lists of genetic variants simple and accessible, we have developed a new Web-based system called VAS (Variant Annotation System, available at https://yiplab.cse.cuhk.edu.hk/vas/). It provides a large variety of information useful for studying both coding and non-coding variants, including whole-genome transcription factor binding, open chromatin and transcription data from the ENCODE consortium. By means of data compression, millions of variants can be uploaded from a client machine to the server in less than 50 megabytes of data. On the server side, our customized data integration algorithms can efficiently link millions of variants with tens of whole-genome datasets. These two enabling technologies make VAS a practical tool for annotating genetic variants from large genomic studies. We demonstrate the use of VAS in annotating genetic variants obtained from a migraine meta-analysis study and multiple data sets from the Personal Genomes Project. We also compare the running time of annotating 6.4 million SNPs of the CEU trio by VAS and another tool, showing that VAS is efficient in handling new variant lists without requiring any pre-computations. CONCLUSIONS: VAS is specially designed to handle annotation tasks with long lists of genetic variants and large numbers of annotating features efficiently. It is complementary to other existing tools with more specific aims such as evaluating the potential impacts of genetic variants in terms of disease risk. We recommend using VAS for a quick first-pass identification of potentially interesting genetic variants, to minimize the time required for other more in-depth downstream analyses.


Assuntos
Variação Genética , Genômica/métodos , Internet , Software , Estudo de Associação Genômica Ampla , Humanos , Fatores de Tempo , Interface Usuário-Computador
14.
PLoS One ; 19(4): e0300587, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38625860

RESUMO

Tracking has been criticized for relegating disadvantaged students to lower track courses in which students encounter a greater lack of instructional support. While an end to tracks through detracking is a possible solution, there are concerns that detracking will create more heterogeneous classrooms, making it harder for teachers to provide adequate support to their students. Using the 2015 PISA dataset, this study conducts a causal inferential analysis to understand the differences in student perceptions of teaching in tracked and untracked environments. The results provide evidence that students' needs, with respect to adaptation of instruction and provision of individualized feedback and support, are being met to the same extent on average in tracked and untracked science classes, suggesting that teachers may not necessarily have a harder time meeting the needs of students in untracked classes.


Assuntos
Pessoal de Educação , Estudantes , Humanos , Retroalimentação
15.
Artigo em Inglês | MEDLINE | ID: mdl-39236299

RESUMO

OBJECTIVE: Novel technology-based interventions have the potential to improve motor symptoms and gait in Parkinson's disease (PD). Promising treatments include virtual-reality (VR) training, robotic assistance, and biofeedback. Their effectiveness remains unclear, and thus, we conducted a Bayesian network meta-analysis. METHODS: We searched the Medline, Embase, Cochrane CENTRAL, and Clinicaltrials.gov databases until 2 April 2024 and only included randomized controlled trials. Outcomes included changes in UPDRS-III/MDS-UPDRS-III score, stride length, 10-meter walk test (10MWT), timed up-and-go (TUG) test, balance scale scores and quality-of-life (QoL) scores. Results were reported as mean differences (MD) or standardized mean differences (SMD), with 95% credible intervals (95% CrI). RESULTS: Fifty-one randomized controlled trials with 2095 patients were included. For UPDRS (motor outcome), all interventions had similar efficacies. VR intervention was the most effective in improving TUG compared with control (MD: -4.36, 95% CrI: -8.57, -0.35), outperforming robotic, exercise, and proprioceptive interventions. Proprioceptive intervention significantly improved stride length compared to control intervention (MD: 0.11 m, 95% CrI: 0.03, 0.19), outperforming VR, robotic and exercise interventions. Virtual reality improved balance scale scores significantly compared to exercise intervention (SMD: 0.75, 95% CrI: 0.12, 1.39) and control intervention (SMD: 1.42, 95% CrI: 0.06, 2.77). Virtual reality intervention significantly improved QoL scores compared to control intervention (SMD: -0.95, 95% CrI: -1.43, -0.52), outperforming Internet-based interventions. INTERPRETATION: VR-based and proprioceptive interventions were the most promising interventions, consistently ranking as the top treatment choices for most outcomes. Their use in clinical practice could be helpful in managing motor symptoms and QoL in PD.

16.
Biomaterials ; 314: 122818, 2024 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-39260032

RESUMO

Injuries to the central nervous system, such as stroke and traumatic spinal cord injury, result in an aggregate scar that both limits tissue degeneration and inhibits tissue regeneration. The aggregate scar includes chondroitin sulfate proteoglycans (CSPGs), which impede cell migration and axonal outgrowth. Chondroitinase ABC (ChASE) is a potent yet fragile enzyme that degrades CSPGs, and thus may enable tissue regeneration. ChASE37, with 37-point mutations to the native enzyme, has been shown to be more stable than ChASE, but its efficacy has never been tested. To answer this question, we investigated the efficacy of ChASE37 first in vitro using human cell-based assays and then in vivo in a rodent model of stroke. We demonstrated ChASE37 degradation of CSPGs in vitro and the consequent cell adhesion and axonal sprouting now possible using human induced pluripotent stem cell (hiPSC)-derived neurons. To enable prolonged release of ChASE37 to injured tissue, we expressed it as a fusion protein with a Src homology 3 (SH3) domain and modified an injectable, carboxymethylcellulose (CMC) hydrogel with SH3-binding peptides (CMC-bp) using inverse electron-demand Diels-Alder chemistry. We injected this affinity release CMC-bp/SH3-ChASE37 hydrogel epicortically to endothelin-1 stroke-injured rats and confirmed bioactivity via degradation of CSPGs and axonal sprouting in and around the lesion. With CSPG degradation shown both in vitro by greater cell interaction and in vivo with local delivery from a sustained release formulation, we lay the foundation to test the potential of ChASE37 and its delivery by local affinity release for tissue regeneration after stroke.

17.
BMC Bioinformatics ; 14 Suppl 2: S9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23368518

RESUMO

BACKGROUND: Polyadenylation is present in all three domains of life, making it the most conserved post-transcriptional process compared with splicing and 5'-capping. Even though most mammalian poly(A) sites contain a highly conserved hexanucleotide in the upstream region and a far less conserved U/GU-rich sequence in the downstream region, there are many exceptions. Furthermore, poly(A) sites in other species, such as plants and invertebrates, exhibit high deviation from this genomic structure, making the construction of a general poly(A) site recognition model challenging. We surveyed nine poly(A) site prediction methods published between 1999 and 2011. All methods exploit the skewed nucleotide profile across the poly(A) sites, and the highly conserved poly(A) signal as the primary features for recognition. These methods typically use a large number of features, which increases the dimensionality of the models to crippling degrees, and typically are not validated against many kinds of genomes. RESULTS: We propose a poly(A) site model that employs minimal features to capture the essence of poly(A) sites, and yet, produces better prediction accuracy across diverse species. Our model consists of three dior-trinucleotide profiles identified through principle component analysis, and the predicted nucleosome occupancy flanking the poly(A) sites. We validated our model using two machine learning methods: logistic regression and linear discriminant analysis. Results show that models achieve 85-92% sensitivity and 85-96% specificity in seven animals and plants. When we applied one model from one species to predict poly(A) sites from other species, the sensitivity scores correlate with phylogenetic distances. CONCLUSIONS: A four-feature model geared towards small motifs was sufficient to accurately learn and predict poly(A) sites across eukaryotes.


Assuntos
Inteligência Artificial , Modelos Teóricos , Poliadenilação , RNA Mensageiro/genética , Animais , Sequência Conservada/genética , Análise Discriminante , Modelos Logísticos , Nucleossomos/genética , Filogenia , Plantas/genética , Poli A/genética , Análise de Componente Principal , Sensibilidade e Especificidade
18.
BMC Psychiatry ; 13: 7, 2013 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-23289525

RESUMO

BACKGROUND: Prior animal model and human-based studies have linked selenium concentrations to decreased risk for depression; however, this work has not focused on household groundwater levels or specific depressive symptoms. The current study evaluated the link between groundwater selenium levels and depression. We also sought to determine if a functional polymorphism in the glutathione peroxidase 1 (GPX1) gene impacted this link. METHODS: We used a cross-sectional design to analyze data from 585 participants (183 men and 402 women) from Project FRONTIER, a study of rural health in West Texas. Residential selenium concentrations were estimated using Geospatial Information System (GIS) analyses. Linear regression models were created using Geriatric Depression Scale (GDS-30) total and subfactor scores as outcome variables and selenium concentrations as predictor variables. Analyses were re-run after stratification of the sample on GPX1 Pro198Leu genotype (rs1050454). RESULTS: Selenium levels were significantly and negatively related to all GDS and subfactor scores accounting for up to 17% of the variance beyond covariates. Selenium was most strongly protective against depression among homozygous carriers of the C allele at the Pro198Leu polymorphism of the GPX1 gene. Analyses also point towards a gene-environmental interaction between selenium exposure and GPX1 polymorphism. CONCLUSION: Our results support the link between groundwater selenium levels and decreased depression symptoms. These findings also highlight the need to consider the genetics of the glutathione peroxidase system when examining this relationship, as variation in the GPX1 gene is related to depression risk and significantly influences the protective impact of selenium, which is indicative of a gene-environment interaction.


Assuntos
Depressão/etiologia , Glutationa Peroxidase/genética , Água Subterrânea/análise , Selênio/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Estudos Transversais , Depressão/genética , Água Potável/análise , Feminino , Interação Gene-Ambiente , Predisposição Genética para Doença/epidemiologia , Predisposição Genética para Doença/genética , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Texas/epidemiologia , Glutationa Peroxidase GPX1
19.
Skeletal Radiol ; 42(11): 1549-54, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23955581

RESUMO

OBJECTIVE: An accurate in vivo method of measuring dimensions of the anteromedial (AM) and posterolateral (PL) anterior cruciate ligament (ACL) bundles has not been established. The purpose of this study was to measure each individual bundle using double oblique axial MR imaging of the ACL, to compare this with cadaveric measurements, and to investigate the range of measurements seen in normal subjects. MATERIALS AND METHODS: In five cadaveric knees, measurements obtained of the proximal, middle, and distal segments of each ACL bundle from double oblique axial MR images were compared with direct measurements following anatomical dissection. Thereafter, the size of both bundles from 24 normal knees was measured using an identical MR technique. Inter-observer variation was calculated using intraclass correlation. RESULTS: ACL bundle measurement in the cadaveric knees had a strong correlation (r = 0.93) with measurements obtained following anatomical dissection. No significant difference existed between measurements obtained from cadaveric knees and living normal subjects (p > 0.05). Interobserver correlation for MR measurements was excellent (R = 0.92-0.93). Overall, the long and short axis of the AM bundle were significantly larger than those of the PL bundle (p < 0.05). Also, men showed significantly larger AM and PL bundles than women (p < 0.05). Bundle size was not related to age or knee dominance. CONCLUSION: The individual ACL bundles can be accurately measured on double oblique axial MR imaging. The AM bundle is larger in caliber than the PL bundle. Both bundles are larger in men than in women and there is no significant side-to side difference.


Assuntos
Ligamento Cruzado Anterior/anatomia & histologia , Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso , Cadáver , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
PeerJ ; 11: e16343, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38025700

RESUMO

Background: The rapid emergence of antibiotic-resistant bacteria directly contributes to a wave of untreatable infections. The lack of new drug development is an important driver of this crisis. Most antibiotics today are small molecules that block vital processes in bacteria. To optimize such effects, the three-dimensional structure of targeted bacterial proteins is imperative, although such a task is time-consuming and tedious, impeding the development of antibiotics. The development of RNA-based therapeutics has catalyzed a new platform of antibiotics-antisense oligonucleotides (ASOs). These molecules hybridize with their target mRNAs with high specificity, knocking down or interfering with protein translation. This study aims to develop a bioinformatics pipeline to identify potent ASO targets in essential bacterial genes. Methods: Three bacterial species (P. gingivalis, H. influenzae, and S. aureus) were used to demonstrate the utility of the pipeline. Open reading frames of bacterial essential genes were downloaded from the Database of Essential Genes (DEG). After filtering for specificity and accessibility, ASO candidates were ranked based on their self-hybridization score, predicted melting temperature, and the position on the gene in an operon. Enrichment analysis was conducted on genes associated with putative potent ASOs. Results: A total of 45,628 ASOs were generated from 348 unique essential genes in P. gingivalis. A total of 1,117 of them were considered putative. A total of 27,273 ASOs were generated from 191 unique essential genes in H. influenzae. A total of 847 of them were considered putative. A total of 175,606 ASOs were generated from 346 essential genes in S. aureus. A total of 7,061 of them were considered putative. Critical biological processes associated with these genes include translation, regulation of cell shape, cell division, and peptidoglycan biosynthetic process. Putative ASO targets generated for each bacterial species are publicly available here: https://github.com/EricSHo/AOA. The results demonstrate that our bioinformatics pipeline is useful in identifying unique and accessible ASO targets in bacterial species that post major public health issues.


Assuntos
Antibacterianos , Oligonucleotídeos Antissenso , Oligonucleotídeos Antissenso/genética , Antibacterianos/farmacologia , Staphylococcus aureus/genética , Oligonucleotídeos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA