Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Jt Comm J Qual Patient Saf ; 43(4): 166-175, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28325204

RESUMO

BACKGROUND: As the health care system in the United States places greater emphasis on the public reporting of quality and safety data and its use to determine payment, provider organizations must implement structures that ensure discipline and rigor regarding these data. An academic health system, as part of a performance management system, applied four key components of a financial reporting structure to support the goal of top-to-bottom accountability for improving quality and safety. FOUR KEY COMPONENTS OF A FINANCIAL REPORTING STRUCTURE: The four components implemented by Johns Hopkins Medicine were governance, accountability, reporting of consolidated quality performance statements, and auditing. Governance is provided by the health system's Patient Safety and Quality Board Committee, which reviews goals and strategy for patient safety and quality, reviews quarterly performance for each entity, and holds organizational leaders accountable for performance. An accountability plan includes escalating levels of review corresponding to the number of months an entity misses the defined performance target for a measure. A consolidated quality statement helps inform the Patient Safety and Quality Board Committee and leadership on key quality and safety issues. An audit evaluates the efficiency and effectiveness of processes for data collection, validation, and storage, as to ensure the accuracy and completeness of quality measure reporting. CONCLUSION: If hospitals and health systems truly want to prioritize improvements in safety and quality, they will need to create a performance management system that ensures data validity and supports performance accountability. Without valid data, it is difficult to know whether a performance gap is due to data quality or clinical quality.


Assuntos
Atenção à Saúde/organização & administração , Economia Hospitalar , Administração Financeira , Qualidade da Assistência à Saúde , Contabilidade/normas , Auditoria Clínica , Atenção à Saúde/economia , Atenção à Saúde/normas , Setor de Assistência à Saúde/economia , Setor de Assistência à Saúde/organização & administração , Pesquisa sobre Serviços de Saúde , Hospitais/normas , Humanos , Maryland , Segurança do Paciente , Estados Unidos
2.
Nucleic Acids Res ; 40(20): 10161-71, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22941653

RESUMO

High mobility group protein 1 (HMGB1) interacts with DNA and chromatin to influence the regulation of transcription, DNA repair and recombination. We show that HMGB1 alters the structure and stability of the canonical nucleosome (N) in a nonenzymatic, ATP-independent manner. Although estrogen receptor (ER) does not bind to its consensus estrogen response element within a nucleosome, HMGB1 restructures the nucleosome to facilitate strong ER binding. The isolated HMGB1-restructured nucleosomes (N' and N″) remain stable and exhibit characteristics distinctly different from the canonical nucleosome. These findings complement previous studies that showed (i) HMGB1 stimulates in vivo transcriptional activation at estrogen response elements and (ii) knock down of HMGB1 expression by siRNA precipitously reduced transcriptional activation. The findings indicate that one aspect of the mechanism of HMGB1 action involves a restructuring of the nucleosome that appears to relax structural constraints within the nucleosome.


Assuntos
Proteína HMGB1/metabolismo , Nucleossomos/química , Nucleossomos/metabolismo , Receptores de Estrogênio/metabolismo , Montagem e Desmontagem da Cromatina , Desoxirribonuclease I , Ensaio de Desvio de Mobilidade Eletroforética
3.
J Biomol NMR ; 50(4): 421-30, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21748265

RESUMO

Comprehensive application of solution NMR spectroscopy to studies of macromolecules remains fundamentally limited by the molecular rotational correlation time. For proteins, molecules larger than 30 kDa require complex experimental methods, such as TROSY in conjunction with isotopic labeling schemes that are often expensive and generally reduce the potential information available. We have developed the reverse micelle encapsulation strategy as an alternative approach. Encapsulation of proteins within the protective nano-scale water pool of a reverse micelle dissolved in ultra-low viscosity nonpolar solvents overcomes the slow tumbling problem presented by large proteins. Here, we characterize the contributions from the various components of the protein-containing reverse micelle system to the rotational correlation time of the encapsulated protein. Importantly, we demonstrate that the protein encapsulated in the reverse micelle maintains a hydration shell comparable in size to that seen in bulk solution. Using moderate pressures, encapsulation in ultra-low viscosity propane or ethane can be used to magnify this advantage. We show that encapsulation in liquid ethane can be used to reduce the tumbling time of the 43 kDa maltose binding protein from ~23 to ~10 ns. These conditions enable, for example, acquisition of TOCSY-type data resolved on the adjacent amide NH for the 43 kDa encapsulated maltose binding protein dissolved in liquid ethane, which is typically impossible for proteins of such size without use of extensive deuteration or the TROSY effect.


Assuntos
Micelas , Ressonância Magnética Nuclear Biomolecular/métodos , Proteínas/química , Cetrimônio , Compostos de Cetrimônio/química , Proteínas de Escherichia coli/química , Etano/química , Hexanóis/química , Humanos , Proteínas Ligantes de Maltose/química , Peso Molecular , Tensoativos/química , Viscosidade , Água/química
4.
Neurodegener Dis ; 6(1-2): 23-8, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19066433

RESUMO

BACKGROUND: Impaired antioxidant defenses are implicated in neurodegenerative disease. The plasma levels of urate, a water-soluble antioxidant, are reduced in Alzheimer's disease (AD). OBJECTIVE: We aimed to test the hypotheses that high plasma urate at baseline is associated with: (1) a reduced rate of conversion from mild cognitive impairment (MCI) to AD and (2) a lower rate of cognitive decline in MCI. METHODS: Plasma urate was obtained at baseline from 747 participants in a 3-year, randomized, double-blind, placebo-controlled study of donepezil, vitamin E or placebo for delaying the progression of MCI to AD.The association between baseline urate and conversion from MCI to AD was examined by Cox proportional hazards regression. The relationship between baseline urate and cognitive change on the cognitive subscale of the Alzheimer's Disease Assessment Scale was evaluated by longitudinal analysis. RESULTS: Baseline plasma urate was not associated with the rate of conversion of MCI to AD. In the placebo arm, high plasma urate was related to a slower rate of cognitive decline over 3 years, although this was not reproduced in the other treatment arms. CONCLUSION: While plasma urate levels did not predict the progression of MCI to AD, high urate may be associated with a reduced rate of cognitive decline in MCI patients not treated with donepezil or vitamin E. The results support the investigation of biomarkers of antioxidant status as risk factors for cognitive decline in MCI.


Assuntos
Transtornos Cognitivos/sangue , Transtornos Cognitivos/fisiopatologia , Ácido Úrico/sangue , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/epidemiologia , Boston/epidemiologia , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/mortalidade , Fatores de Confusão Epidemiológicos , Demência/epidemiologia , Progressão da Doença , Donepezila , Feminino , Humanos , Incidência , Indanos/uso terapêutico , Masculino , Pessoa de Meia-Idade , Nootrópicos/uso terapêutico , Piperidinas/uso terapêutico , Prevalência , Análise de Sobrevida , Vitamina E/uso terapêutico
5.
Acta Crystallogr C ; 65(Pt 11): i81-4, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19893219

RESUMO

The structure of synthetic disodium magnesium disulfate decahydrate at 180 K consists of alternating layers of water-coordinated [Mg(H(2)O)(6)](2+) octahedra and [Na(2)(SO(4))(2)(H(2)O)(4)](2-) sheets, parallel to [100]. The [Mg(H(2)O)(6)](2+) octahedra are joined to one another by a single hydrogen bond, the other hydrogen bonds being involved in inter-layer linkage. The Mg(2+) cation occupies a crystallographic inversion centre. The sodium-sulfate sheets consist of chains of water-sharing [Na(H(2)O)(6)](+) octahedra along b, which are then connected by sulfate tetrahedra through corner-sharing. The associated hydrogen bonds are the result of water-sulfate interactions within the sheets themselves. This is believed to be the first structure of a mixed monovalent/divalent cation sulfate decahydrate salt.

7.
J Health Organ Manag ; 32(1): 2-8, 2018 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-29508668

RESUMO

Purpose The purpose of this paper is to offer six principles that health system leaders can apply to establish a governance and management system for the quality of care and patient safety. Design/methodology/approach Leaders of a large academic health system set a goal of high reliability and formed a quality board committee in 2011 to oversee quality and patient safety everywhere care was delivered. Leaders of the health system and every entity, including inpatient hospitals, home care companies, and ambulatory services staff the committee. The committee works with the management for each entity to set and achieve quality goals. Through this work, the six principles emerged to address management structures and processes. Findings The principles are: ensure there is oversight for quality everywhere care is delivered under the health system; create a framework to organize and report the work; identify care areas where quality is ambiguous or underdeveloped (i.e. islands of quality) and work to ensure there is reporting and accountability for quality measures; create a consolidated quality statement similar to a financial statement; ensure the integrity of the data used to measure and report quality and safety performance; and transparently report performance and create an explicit accountability model. Originality/value This governance and management system for quality and safety functions similar to a finance system, with quality performance documented and reported, data integrity monitored, and accountability for performance from board to bedside. To the authors' knowledge, this is the first description of how a board has taken this type of systematic approach to oversee the quality of care.


Assuntos
Conselho Diretor/organização & administração , Qualidade da Assistência à Saúde/organização & administração , Instituições de Assistência Ambulatorial/organização & administração , Serviços de Assistência Domiciliar/organização & administração , Administração Hospitalar , Humanos , Objetivos Organizacionais , Segurança do Paciente/normas , Qualidade da Assistência à Saúde/normas
8.
Protein Sci ; 14(11): 2919-21, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16199658

RESUMO

NMR spectroscopy of encapsulated proteins dissolved in low-viscosity fluids is emerging as a tool for biophysical studies of proteins in atomic detail in a variety of otherwise inaccessible contexts. The central element of the approach is the encapsulation of the protein of interest within the aqueous core of a reverse micelle with high structural fidelity. The process of encapsulation is highly dependent upon the nature of the surfactant(s) employed. Here we describe novel mixtures of surfactants that are capable of successfully encapsulating a range of types of proteins under a variety of conditions.


Assuntos
Ressonância Magnética Nuclear Biomolecular , Proteínas/química , Tensoativos/química , Cetrimônio , Compostos de Cetrimônio/química , Ácido Dioctil Sulfossuccínico/química , Humanos , Ubiquitina/química , Viscosidade
9.
J Mol Biol ; 321(2): 355-62, 2002 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-12144791

RESUMO

The energetic consequences of site-specific replacement of a residue at a partially buried site in the two homologous HPr proteins from Escherichia coli and Bacillus subtilis is described. We determined previously that the replacement of a partially buried Lys residue with Glu at position 49 in E.coli HPr increased the conformational stability of the protein substantially because the side-chain of the latter residue could act as a hydrogen-bond acceptor. Here, we extend this analysis to other side-chains with different chemical properties and abilities to form hydrogen bonds to compare the properties of this position in the backgrounds of two different homologous HPr proteins. We find that the variants with polar residues that can form a tertiary hydrogen bond with a nearby site in the protein are more stable than either hydrophobic residues or polar residues that become buried yet are incapable of forming a new hydrogen bond. Furthermore, the protein with the wild-type residue in each HPr variant is not among the most stable of the proteins studied. These results suggest a general strategy for designing variants in which the overall stability of a protein can be modulated in a defined fashion.


Assuntos
Bacillus subtilis/química , Proteínas de Bactérias , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/química , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo , Substituição de Aminoácidos/genética , Bacillus subtilis/genética , Sítios de Ligação , Escherichia coli/química , Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Temperatura Alta , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/genética , Conformação Proteica/efeitos dos fármacos , Desnaturação Proteica/efeitos dos fármacos , Dobramento de Proteína , Homologia de Sequência de Aminoácidos , Termodinâmica , Ureia/farmacologia
10.
J Magn Reson ; 175(1): 158-62, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15949753

RESUMO

Traditionally, large proteins, aggregation-prone proteins, and membrane proteins have been difficult to examine by modern multinuclear and multidimensional solution NMR spectroscopy. A major limitation presented by these protein systems is that their slow molecular reorientation compromises many aspects of the more powerful solution NMR methods. Several approaches have emerged to deal with the various spectroscopic difficulties arising from slow molecular reorientation. One of these takes the approach of actively seeking to increase the effective rate of molecular reorientation by encapsulating the protein of interest within the protective shell of a reverse micelle and dissolving the resulting particle in a low viscosity fluid. Since the encapsulation is largely driven by electrostatic interactions, the preparation of samples of acidic proteins suitable for NMR spectroscopy has been problematic owing to the paucity of suitable cationic surfactants. Here, it is shown that the cationic surfactant CTAB may be used to prepare samples of encapsulated anionic proteins dissolved in low viscosity solvents. In a more subtle application, it is further shown that this surfactant can be employed to encapsulate a highly basic protein, which is completely denatured upon encapsulation using an anionic surfactant.


Assuntos
Compostos de Cetrimônio/química , Materiais Revestidos Biocompatíveis/análise , Materiais Revestidos Biocompatíveis/química , Citocromos c/análise , Citocromos c/química , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/química , Espectroscopia de Ressonância Magnética/métodos , Animais , Cátions , Cetrimônio , Cavalos , Miocárdio/enzimologia , Proteínas/análise , Proteínas/química , Manejo de Espécimes/métodos , Tensoativos/química
11.
Mol Endocrinol ; 18(11): 2616-32, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15256536

RESUMO

The estrogen receptor alpha (ER) is a ligand-dependent transcription factor that regulates the expression of estrogen-responsive genes. A key step in the activation process is the initial binding of the ER dimer to the estrogen response element (ERE). We examined the effect of the coactivator proteins, HMGB1 and HMGB2, in enhancing ER binding affinity to single and tandem EREs. Using EMSAs, both HMGB proteins are shown to enhance ER binding and induce cooperative ER binding on tandem ERE elements. We demonstrate that HMGB proteins facilitate strong ER binding to ERE consensus half-sites, exhibiting binding affinities comparable with ER binding to consensus ERE in the absence of HMGB proteins. These findings reveal that although HMGB proteins enhance binding affinity, they also relax ER binding specificity. Deoxyribonuclease I footprinting demonstrates that ER binds very differently to consensus ERE and ERE consensus half-sites, whereas both deoxyribonuclease I and exonuclease III digestions show that the presence of HMGB1/2 does not alter the DNA protection in ER/ERE complexes. Protease digestions of the complexes support this conclusion and show that a global conformation change occurs in ER when bound to the different ER binding sites. Models for these interactions are discussed, together with a hit-and-run mechanism that HMGB proteins may utilize to produce these effects.


Assuntos
Receptor alfa de Estrogênio/metabolismo , Proteína HMGB1/metabolismo , Proteína HMGB2/metabolismo , Elementos de Resposta/genética , Animais , Sequência de Bases , Sequência Consenso , Pegada de DNA , Ensaio de Desvio de Mobilidade Eletroforética , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , Ligação Proteica , Estrutura Terciária de Proteína
12.
Rev Sci Instrum ; 76(9): 1-7, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16508692

RESUMO

The design of a sample cell for high performance nuclear magnetic resonance (NMR) at elevated pressure is described. The cell has been optimized for the study of encapsulated proteins dissolved in low viscosity fluids but is suitable for more general NMR spectroscopy of biomolecules at elevated pressure. The NMR cell is comprised of an alumina toughened zirconia tube mounted on a self-sealing non-magnetic metallic valve. The cell has several advantages including relatively low cost, excellent NMR performance, high pressure tolerance, chemical inertness and a relatively large active volume. Also described is a low volume sample preparation device which allows for the preparation of samples under high hydrostatic pressure and their subsequent transfer to the NMR cell.

13.
Acad Med ; 90(2): 165-72, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25517699

RESUMO

In this article, the authors describe an initiative that established an infrastructure to manage quality and safety efforts throughout a complex health care system and that improved performance on core measures for acute myocardial infarction, heart failure, pneumonia, surgical care, and children's asthma. The Johns Hopkins Medicine Board of Trustees created a governance structure to establish health care system-wide oversight and hospital accountability for quality and safety efforts throughout Johns Hopkins Medicine. The Armstrong Institute for Patient Safety and Quality was formed; institute leaders used a conceptual model nested in a fractal infrastructure to implement this initiative to improve performance at two academic medical centers and three community hospitals, starting in March 2012. The initiative aimed to achieve ≥ 96% compliance on seven inpatient process-of-care core measures and meet the requirements for the Delmarva Foundation and Joint Commission awards. The primary outcome measure was the percentage of patients at each hospital who received the recommended process of care. The authors compared health system and hospital performance before (2011) and after (2012, 2013) the initiative. The health system achieved ≥ 96% compliance on six of the seven targeted measures by 2013. Of the five hospitals, four received the Delmarva Foundation award and two received The Joint Commission award in 2013. The authors argue that, to improve quality and safety, health care systems should establish a system-wide governance structure and accountability process. They also should define and communicate goals and measures and build an infrastructure to support peer learning.


Assuntos
Atenção à Saúde/organização & administração , Avaliação de Processos em Cuidados de Saúde , Melhoria de Qualidade/organização & administração , Centros Médicos Acadêmicos , Adulto , Asma/terapia , Criança , Insuficiência Cardíaca/terapia , Hospitalização , Hospitais Comunitários , Humanos , Maryland , Infarto do Miocárdio/terapia , Assistência Perioperatória , Pneumonia/terapia
14.
Protein Sci ; 13(3): 735-51, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14978310

RESUMO

Accurate prediction of the placement and comformations of protein side chains given only the backbone trace has a wide range of uses in protein design, structure prediction, and functional analysis. Prediction has most often relied on discrete rotamer libraries so that rapid fitness of side-chain rotamers can be assessed against some scoring function. Scoring functions are generally based on experimental parameters from small-molecule studies or empirical parameters based on determined protein structures. Here, we describe the NCN algorithm for predicting the placement of side chains. A predominantly first-principles approach was taken to develop the potential energy function incorporating van der Waals and electrostatics based on the OPLS parameters, and a hydrogen bonding term. The only empirical knowledge used is the frequency of rotameric states from the PDB. The rotamer library includes nearly 50,000 rotamers, and is the most extensive discrete library used to date. Although the computational time tends to be longer than most other algorithms, the overall accuracy exceeds all algorithms in the literature when placing rotamers on an accurate backbone trace. Considering only the most buried residues, 80% of the total residues tested, the placement accuracy reaches 92% for chi(1), and 83% for chi(1 + 2), and an overall RMS deviation of 1 A. Additionally, we show that if information is available to restrict chi(1) to one rotamer well, then this algorithm can generate structures with an average RMS deviation of 1.0 A for all heavy side-chains atoms and a corresponding overall chi(1 + 2) accuracy of 85.0%.


Assuntos
Algoritmos , Bases de Dados de Proteínas , Conformação Proteica , Aminoácidos/química , Biologia Computacional/métodos , Simulação por Computador , Ligação de Hidrogênio , Modelos Moleculares , Proteínas/química , Reprodutibilidade dos Testes , Eletricidade Estática , Termodinâmica
15.
Astrobiology ; 14(11): 887-968, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25401393

RESUMO

A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003). Results have also been gleaned from the Mars Science Laboratory (launched in 2011). In addition to Mars data, there is a considerable body of new data regarding the known environmental limits to life on Earth-including the potential for terrestrial microbial life to survive and replicate under martian environmental conditions. The SR-SAG2 analysis has included an examination of new Mars models relevant to natural environmental variation in water activity and temperature; a review and reconsideration of the current parameters used to define Special Regions; and updated maps and descriptions of the martian environments recommended for treatment as "Uncertain" or "Special" as natural features or those potentially formed by the influence of future landed spacecraft. Significant changes in our knowledge of the capabilities of terrestrial organisms and the existence of possibly habitable martian environments have led to a new appreciation of where Mars Special Regions may be identified and protected. The SR-SAG also considered the impact of Special Regions on potential future human missions to Mars, both as locations of potential resources and as places that should not be inadvertently contaminated by human activity.


Assuntos
Exobiologia , Marte , Voo Espacial , Bactérias/citologia , Bactérias/metabolismo , Divisão Celular , Temperatura Baixa , Metabolismo Energético , Meio Ambiente Extraterreno , Fungos/citologia , Fungos/metabolismo , Geografia , Humanos , Gelo , Viabilidade Microbiana , Oxigênio , Voo Espacial/instrumentação , Astronave , Termodinâmica , Raios Ultravioleta , Água , Leveduras/citologia , Leveduras/metabolismo
17.
J Magn Reson ; 212(1): 229-33, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21764613

RESUMO

Encapsulation within reverse micelles dissolved in low viscosity fluids offers a potential solution to the slow tumbling problem presented by large soluble macromolecules to solution NMR spectroscopy. The reduction in effective macromolecular tumbling is directly dependent upon the viscosity of the solvent. Liquid ethane is of sufficiently low viscosity at pressures below 5000 psi to offer a significant advantage. Unfortunately, the viscosity of liquid ethane shows appreciable pressure dependence. Reverse micelle encapsulation in liquid ethane often requires significantly higher pressures, which obviates the potential advantages offered by liquid ethane over liquid propane. Addition of co-surfactants or co-solvents can be used to manipulate the minimum pressure required to obtain stable, well-behaved solutions of reverse micelles prepared in liquid ethane. A library of potential additives is examined and several candidates suitable for use with encapsulated proteins are described.


Assuntos
Etano/química , Proteínas/química , Álcoois/química , Algoritmos , Dióxido de Carbono/química , Dissulfeto de Carbono/química , Cetrimônio , Compostos de Cetrimônio/química , Temperatura Baixa , Ácido Dioctil Sulfossuccínico , Indicadores e Reagentes , Micelas , Pressão , Propano , Soluções , Solventes , Succinatos/química , Tensoativos , Viscosidade
19.
Neurobiol Aging ; 31(8): 1340-54, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20570401

RESUMO

Previously it was reported that Alzheimer's disease (AD) patients have reduced beta amyloid (Abeta(1-42)) and elevated total tau (t-tau) and phosphorylated tau (p-tau(181p)) in the cerebrospinal fluid (CSF), suggesting that these same measures could be used to detect early AD pathology in healthy elderly individuals and those with mild cognitive impairment (MCI). In this study, we tested the hypothesis that there would be an association among rates of regional brain atrophy, the CSF biomarkers Abeta(1-42), t-tau, and p-tau(181p) and apolipoprotein E (ApoE) epsilon4 status, and that the pattern of this association would be diagnosis-specific. Our findings primarily showed that lower CSF Abeta(1-42) and higher tau concentrations were associated with increased rates of regional brain tissue loss and the patterns varied across the clinical groups. Taken together, these findings demonstrate that CSF biomarker concentrations are associated with the characteristic patterns of structural brain changes in healthy elderly and mild cognitive impairment subjects that resemble to a large extent the pathology seen in AD. Therefore, the finding of faster progression of brain atrophy in the presence of lower Abeta(1-42) levels and higher tau levels supports the hypothesis that CSF Abeta(1-42) and tau are measures of early AD pathology. Moreover, the relationship among CSF biomarkers, ApoE epsilon4 status, and brain atrophy rates are regionally varying, supporting the view that the genetic predisposition of the brain to beta amyloid and tau mediated pathology is regional and disease stage specific.


Assuntos
Doença de Alzheimer/líquido cefalorraquidiano , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Apolipoproteína E4/genética , Encéfalo/patologia , Fragmentos de Peptídeos/líquido cefalorraquidiano , Proteínas tau/líquido cefalorraquidiano , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Apolipoproteína E4/biossíntese , Atrofia , Biomarcadores/líquido cefalorraquidiano , Transtornos Cognitivos/líquido cefalorraquidiano , Transtornos Cognitivos/genética , Transtornos Cognitivos/patologia , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética/métodos , Masculino , Estudos Prospectivos
20.
Structure ; 18(1): 9-16, 2010 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-20152148

RESUMO

Perhaps 5%-10% of proteins bind to membranes via a covalently attached lipid. Posttranslational attachment of fatty acids such as myristate occurs on a variety of viral and cellular proteins. High-resolution information about the nature of lipidated proteins is remarkably sparse, often because of solubility problems caused by the exposed fatty acids. Reverse micelle encapsulation is used here to study two myristoylated proteins in their lipid-extruded states: myristoylated recoverin, which is a switch in the Ca(2+) signaling pathway in vision, and the myristoylated HIV-1 matrix protein, which is postulated to be targeted to the plasma membrane through its binding to phosphatidylinositol-4,5-bisphosphate. Both proteins have been successfully encapsulated in the lipid-extruded state and high-resolution NMR spectra obtained. Both proteins bind their activating ligands in the reverse micelle. This approach seems broadly applicable to membrane proteins with exposed fatty acid chains that have eluded structural characterization by conventional approaches.


Assuntos
Proteínas de Membrana/análise , Micelas , Ressonância Magnética Nuclear Biomolecular/métodos , Cápsulas/química , Ácidos Graxos/química , Antígenos HIV/análise , Antígenos HIV/química , HIV-1/química , Proteínas de Membrana/química , Recoverina/análise , Recoverina/química , Solubilidade , Produtos do Gene gag do Vírus da Imunodeficiência Humana/análise , Produtos do Gene gag do Vírus da Imunodeficiência Humana/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA