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1.
Psychol Med ; 53(5): 1787-1798, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-34474696

RESUMO

BACKGROUND: Psychosis, even in its early stages, ranks highly among the causes of disability worldwide, resulting in an increased focus on improved recovery of social and occupational functioning. This study aimed to provide an estimate of the effectiveness of psychosocial interventions for improving functioning in early psychosis. We also sought evidence of superiority between intervention approaches. METHODS: An electronic search was conducted using PubMed and PsycINFO to identify original articles reporting on trials of psychosocial interventions in early-stage psychosis, published up to December 2020 and is reported following PRISMA guidelines. Data were extracted on validated measures of functioning from included studies and pooled standardised mean difference (SMD) was estimated. RESULTS: In total, 31 studies involving 2811 participants were included, focusing on: cognitive behavioural therapy for psychosis (CBTp), family-based therapy, supported employment, cognitive remediation training (CRT) and multi-component psychosocial interventions. Across interventions, improved function was observed (SMD = 0.239; 95% confidence interval 0.115-0.364, p < 0.001). Effect sizes varied by intervention type, stage of illness, length and duration of treatment and outcome measure used. In particular, interventions based on CRT significantly outperformed symptom-focused CBT interventions, while multi-component interventions were associated with largest gains. CONCLUSIONS: Psychosocial interventions, particularly when provided as part of a multi-component intervention model and delivered in community-based settings are associated with significant improvements in social and occupational function. This review underscores the value of sensitively tracking and targeting psychosocial function as part of the standard provided by early intervention services.


Assuntos
Terapia Cognitivo-Comportamental , Transtornos Psicóticos , Humanos , Intervenção Psicossocial , Transtornos Psicóticos/terapia
2.
Schizophrenia (Heidelb) ; 8(1): 113, 2022 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-36528607

RESUMO

Cognitive impairment is a core feature of psychosis. Full cognitive assessments are not often conducted in routine clinical practice as administration is time-consuming. Here, we investigated whether brief tests of cognition could be used to predict broader neurocognitive performance in a manner practical for screening use in mental health services. We carried out a principal component analysis (PCA) to obtain an estimate of general cognitive function (N = 415). We investigated whether brief tests of memory accounted for a significant percentage of variation in the PCA scores. We used discriminant function analysis to determine if measures could predict classification as lower, intermediate or higher level of cognitive function and to what extent these groups overlapped with groups based on normative data. Memory tests correctly classified 65% of cases in the highest scoring group, 35% of cases in the intermediate group, and 77% of cases in the lowest scoring group. These PCA-derived groups and groups based on normative scores for the two tests were significantly associated (χ2 = 164.00, p < 0.001). These measures accurately identified three quarters of the low performing group, the group of greatest interest from the perspective of identifying those likely to need greater supports as part of clinical care. In so doing they suggest a potentially useful approach to screening for cognitive impairment in clinical services, upon which further assessment can be built if required.

3.
Pilot Feasibility Stud ; 8(1): 109, 2022 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-35610711

RESUMO

BACKGROUND: Psychosis, even in its early stages, is associated with significant disability, causing it to be ranked ahead of paraplegia and blindness in those aged 18-35 in terms of years lived with disability. Current pharmacological and psychological interventions intervention have focused primarily on the reduction of positive symptoms (hallucinations and delusions), with little benefit to domains of psychosis such as cognitive difficulties and social and occupational functioning. METHODS/DESIGN: The CReSt-R intervention trial is a single center, pilot randomised controlled study based at the National University of Ireland (NUI), Galway. The trial will recruit participants from four clinical sites with assessment and intervention completed by the primary NUI Galway team. The trial will explore the feasibility, acceptability, and effectiveness of a novel psychosocial intervention for early psychosis based on a combined cognitive remediation training and cognitive behavioural therapy approach focused on social recovery. Participants, aged 16-35 within the first 5 years of a diagnosed psychotic disorder, will be recruited from the Children and Adolescent Mental Health Service and the Adult Mental Health Services in the region. DISCUSSION: Cognitive remediation training (for improving cognition) and social recovery focused cognitive behavioural therapy, have both separately demonstrated effectiveness. This trial will evaluate the feasibility, acceptability, and explore the efficacy of a treatment approach that combines both approaches as part of an integrated, multicomponent intervention. TRIAL REGISTRATION: Cognitive Remediation & Social Recovery in Early Psychosis (CReSt-R): ClincialTrials.gov Identifier NCT04273685. Trial registered Feb 18th, 2020. Last updated April 14th, 2021.

4.
Osteoarthritis Cartilage ; 30(2): 329-340, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34774790

RESUMO

OBJECTIVE: One driving factor in the progression to posttraumatic osteoarthritis (PTOA) is the perpetuation of the inflammatory response to injury into chronic inflammation. Molecular imaging offers many opportunities to complement the sensitivity of current imaging modalities with molecular specificity. The goal of this study was to develop and characterize agents to image hyaluronan (HA)-mediated inflammatory signaling. DESIGN: We developed optical (Cy5.5-P15-1) and magnetic resonance contrast agents (Gd-DOTA-P15-1) based in a hyaluronan-binding peptide (P15-1) that has shown anti-inflammatory effects on human chondrocytes, and validated them in vitro and in vivo in two animal models of PTOA. RESULTS: In vitro studies with a near infrared (NIR) Cy5.5-P15-1 imaging agent showed a fast and stable localization of Cy5.5-P15-1 on chondrocytes, but not in synovial cells. In vivo NIR showed significantly higher retention of imaging agent in PTOA knees between 12 and 72 h (n = 8, Cohen's d > 2 after 24 h). NIR fluorescence accumulation correlated with histologic severity in cartilage and meniscus (ρ between 0.37 and 0.57, P < 0.001). By using in vivo magnetic resonance imaging with a Gd-DOTA-P15-1 contrast agent in 12 rats, we detected a significant decrease of T1 on injured knees in all cartilage plates at 48 h (-15%, 95%-confidence interval (CI) = [-18%,-11%]) while no change was observed in the controls (-2%, 95%-CI = [-5%,+1%]). CONCLUSIONS: This study provides the first in vivo evidence that hyaluronan-related inflammatory response in cartilage after injury is a common finding. Beyond P15-1, we have demonstrated that molecular imaging can provide a versatile technology to investigate and phenotype PTOA pathogenesis, as well as study therapeutic interventions.


Assuntos
Cartilagem Articular/diagnóstico por imagem , Imagem Multimodal , Osteoartrite do Joelho/diagnóstico por imagem , Animais , Humanos , Receptores de Hialuronatos/fisiologia , Imageamento por Ressonância Magnética , Ratos
5.
Ir J Psychol Med ; 38(1): 6-8, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33715644

RESUMO

People with severe mental illnesses have dramatically reduced life expectancy compared with the general population, which is largely attributed to physical comorbidity. Physical activity and sedentary behaviour interventions offer a safe and viable therapeutic resource for multi-disciplinary mental health care teams. The accumulating evidence supporting the role of these interventions has changed the focus of mental health strategy in some countries, with new developing roles for certain mental health professionals in this field. However, in Ireland the absence of specialised exercise practitioners places a leadership role for mental health nurses in this regard. National mental health strategy in Ireland should prioritise physical activity and sedentary behaviour interventions, make recommendations for the integration of specialised exercise practitioners in all mental health multidisciplinary teams, and recommend the provision of training and awareness for mental health nurses and other multidisciplinary professionals who are already well placed to address this issue.


Assuntos
Transtornos Mentais , Comportamento Sedentário , Exercício Físico , Humanos , Irlanda , Transtornos Mentais/terapia , Saúde Mental
7.
Osteoarthritis Cartilage ; 19(11): 1356-62, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21872669

RESUMO

OBJECTIVES: (1) assess the molecular weight dependence of hyaluronan's (HA) cartilage boundary lubricating ability, alone and in combination with proteoglycan 4 (PRG4), at physiological concentrations; (2) determine if HA and PRG4 interact in solution via electrophoretic mobility shift assay (EMSA). METHODS: The cartilage boundary lubricating ability of a broad range of MW HA (20 kDa, 132 kDa, 780 kDa, 1.5 MDa, and 5 MDa) at 3.33 mg/ml, both alone and in combination with PRG4 at 450 µg/ml, was assessed using a previously described cartilage-on-cartilage friction test. Static, µ(static, Neq), and kinetic, <µ(kinetic, Neq)>, were calculated. An EMSA was conducted with PRG4 and monodisperse 150 kDa and 1,000 kDa HA. RESULTS: Friction coefficients were reduced by HA, in a MW-dependent manner. Values of <µ(kinetic, Neq)> in 20 kDa HA, 0.098 (0.089, 0.108), were significantly greater compared to both 780 kDa, 0.080 (0.072, 0.088), and 5 MDa, 0.079 (0.070, 0.089). Linear regression showed a significant correlation between both µ(static, Neq) and <µ(kinetic, Neq)>, and log HA MW. Friction coefficients were also reduced by PRG4, and with subsequent addition of HA; however the synergistic effect was not dependent on HA MW. Values of <µ(kinetic, Neq)> in PRG4, 0.080 (0.047, 0.113), were significantly greater than values of PRG4+various MW HA (similar in value, averaging 0.040 (0.033, 0.047)). EMSA indicated that migration of 150 kDa and 1,000 kDa HA was retarded when combined with PRG4 at high PRG4:HA ratios. CONCLUSIONS: These results suggest alterations in HA MW could significantly affect synovial fluid's cartilage boundary lubricating ability, yet this diminishment in function could be circumvented by physiological levels of PRG4 forming a complex, potentially in solution, with HA.


Assuntos
Cartilagem Articular/efeitos dos fármacos , Fricção/efeitos dos fármacos , Ácido Hialurônico/farmacologia , Proteoglicanas/farmacologia , Viscossuplementos/farmacologia , Animais , Bovinos , Quimioterapia Combinada , Ensaio de Desvio de Mobilidade Eletroforética , Peso Molecular , Joelho de Quadrúpedes/efeitos dos fármacos
8.
Biophys J ; 75(4): 2030-7, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9746545

RESUMO

The extracellular matrix polysaccharide hyaluronan has been examined by tapping mode atomic force microscopy. High molecular weight hyaluronan was deposited on mica from dilute aqueous solution and imaged in air. Long unbranched chains could be observed and were found to be compatible with the known covalent structure of hyaluronan. In addition, chains with evidence of intramolecular association were observed. In the simplest cases, the association took the form of loops stabilized by antiparallel double-stranded (probably double-helical) segments. In other cases, the polarity of the associated regions could not be determined. Extensive intramolecular association in long hyaluronan chains resulted in a fenestrated structure of the same type as that formed by intermolecular association at higher concentrations.


Assuntos
Ácido Hialurônico/ultraestrutura , Microscopia de Força Atômica/métodos , Animais , Configuração de Carboidratos , Galinhas , Crista e Barbelas , Masculino
9.
Biochem J ; 324 ( Pt 2): 473-9, 1997 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-9182706

RESUMO

NO is a bioactive free radical produced by NO synthase in various tissues including vascular endothelium. One of the degradation products of NO is HNO2, an agent known to degrade heparin and heparan sulphate. This report documents degradation of heparin by cultured endothelial-cell-derived as well as exogenous NO. An exogenous narrow molecular-mass preparation of heparin was recovered from the medium of cultured endothelial cells using strong-anion exchange. In addition, another narrow molecular-mass preparation of heparin was gassed with exogenous NO under argon. Degradation was evaluated by gel-filtration chromatography. Since HNO2 degrades heparin under acidic conditions, the reaction with NO gas was studied under various pH conditions. The results show that the degradation of exogenous heparin by endothelial cells is inhibited by NO synthase inhibitors. Exogenous NO gas at concentrations as low as 400 p.p.m. degrades heparin and heparan sulphate. Exogenous NO degrades heparin at neutral as well as acidic pH. Endothelial-cell-derived NO, as well as exogenous NO gas, did not degrade hyaluronan, an unrelated glycosaminoglycan that resists HNO2 degradation. Peroxynitrite, a metabolic product of the reaction of NO with superoxide, is an agent that degrades hyaluronan; however, peroxynitrite did not degrade heparin. Thus endothelial-cell-derived NO is capable of degrading heparin and heparan sulphate via HNO2 rather than peroxynitrite. These observations may be relevant to various pathophysiological processes in which extracellular matrix is degraded, such as bone development, apoptosis, tissue damage from inflammatory responses and possible release of growth factors and cytokines.


Assuntos
Heparina/metabolismo , Heparitina Sulfato/metabolismo , Óxido Nítrico/farmacologia , Animais , Células Cultivadas , Cromatografia em Gel , Endotélio Vascular/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Ácido Hialurônico/metabolismo , Concentração de Íons de Hidrogênio , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Nitroarginina/farmacologia , Veias Umbilicais , ômega-N-Metilarginina/farmacologia
10.
Arch Biochem Biophys ; 341(2): 245-50, 1997 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-9169011

RESUMO

Treatment of high-molecular-weight hyaluronan (HA) with peroxynitrite at neutral pH (ONOO-/ONOOH) results in altered mobility on agarose gel electrophoresis, as well as reduced limiting viscosity number. Both effects are consistent with a reduction in HA molecular weight. HA is protected from peroxynitrite attack to varying extents by addition of alternate target molecules. Thiourea is extremely effective as a protective agent, dimethyl sulfoxide is moderately effective, while sodium benzoate and mannitol are slightly effective. A similar pattern of protection is observed when HA is degraded by hydroxyl radical generated by a metal ion/hydrogen peroxide system. On the basis of these observations, peroxynitrite is proposed to have hydroxyl radical-like activity in degrading HA.


Assuntos
Ácido Hialurônico/metabolismo , Nitratos/metabolismo , Benzoatos/farmacologia , Ácido Benzoico , Dimetil Sulfóxido/farmacologia , Eletroforese em Gel de Ágar , Radical Hidroxila/metabolismo , Manitol/farmacologia , Peso Molecular , Tioureia/farmacologia , Viscosidade
11.
J Clin Invest ; 98(10): 2403-13, 1996 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-8941660

RESUMO

Hyaluronan (HA) is a glycosaminoglycan constituent of extracellular matrix. In its native form HA exists as a high molecular weight polymer, but during inflammation lower molecular weight fragments accumulate. We have identified a collection of inflammatory genes induced in macrophages by HA fragments but not by high molecular weight HA. These include several members of the chemokine gene family: macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, cytokine responsive gene-2, monocyte chemoattractant protein-1, and regulated on activation, normal T cell expressed and secreted. HA fragments as small as hexamers are capable of inducing expression of these genes in a mouse alveolar macrophage cell line, and monoclonal antibody to the HA receptor CD44 completely blocks binding of fluorescein-labeled HA to these cells and significantly inhibits HA-induced gene expression. We also investigated the ability of HA fragments to induce chemokine gene expression in human alveolar macrophages from patients with idiopathic pulmonary fibrosis and found that interleukin-8 mRNA is markedly induced. These data support the hypothesis that HA fragments generated during inflammation induce the expression of macrophage genes which are important in the development and maintenance of the inflammatory response.


Assuntos
Quimiocina CCL2/genética , Regulação da Expressão Gênica/imunologia , Ácido Hialurônico/imunologia , Proteínas Inflamatórias de Macrófagos/genética , Macrófagos Alveolares/imunologia , Monocinas/genética , Animais , Anticorpos Bloqueadores/imunologia , Anticorpos Monoclonais/imunologia , Northern Blotting , Lavagem Broncoalveolar , Células Cultivadas , Quimiocina CCL4 , Quimiocina CCL5/genética , Quimiocina CXCL10 , Gliceraldeído-3-Fosfato Desidrogenases/genética , Humanos , Receptores de Hialuronatos/imunologia , Inflamação/genética , Interleucina-8/genética , Camundongos , Fibrose Pulmonar/genética , Fibrose Pulmonar/imunologia , RNA Mensageiro/análise , RNA Mensageiro/biossíntese
12.
J Exp Med ; 183(5): 2373-8, 1996 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-8642348

RESUMO

Macrophages play an important role in the acute tissue inflammatory response through the release of cytokines and growth factors in response to stimuli such as lipopolysaccharide (LPS). Macrophage inflammatory effector functions are also influenced by interactions with the extracellular matrix (ECM). Such macrophage-ECM interactions may be important in regulating chronic inflammatory responses. Recent evidence has suggested that hyaluronan (HA), a glycosaminoglycan (GAG) component of ECM can induce inflammatory gene expression in murine macrophages. HA exists in its native form as a large polymer, but is found as smaller fragments under inflammatory conditions. The NF-kappa B/I-kappa B transcriptional regulatory system has been shown to be a critical component of the host inflammatory response. We examined the effects of high molecular weight HA and lower molecular weight HA fragments on NF-kappa B activation in mouse macrophages. Only the smaller HA fragments were found to activate NF-kappa B DNA binding activity. After HA stimulation, I-kappa B alpha mRNA was induced and I-kappa B alpha protein levels, which initially decreased, were restored. The induction of I-kappa Balpha expression was not observed for other GAGs. The time course of I-kappa B alpha protein regeneration in response to HA fragments was consistent with an autoregulatory mechanism. In support of this mechanism, in vitro translated murine I-kappa B alpha inhibited HA fragment-induced NF-kappa B DNA binding activity. The NF-kappa B DNA binding complex in HA-stimulated extracts was found to contain p50 and p65 subunits. Activation of the NF-kappa B/I-kappa B system in macrophages by ECM fragments may be an important mechanism for propagating the tissue inflammatory response.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Ácido Hialurônico/farmacologia , Proteínas I-kappa B , Macrófagos/fisiologia , NF-kappa B/metabolismo , Oligopeptídeos/farmacologia , Animais , Sequência de Bases , Sequência Consenso , Cicloeximida/farmacologia , DNA Complementar , Proteínas de Ligação a DNA/biossíntese , Homeostase , Humanos , Ácido Hialurônico/química , Cadeias kappa de Imunoglobulina/genética , Cinética , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Camundongos , Dados de Sequência Molecular , Inibidor de NF-kappaB alfa , NF-kappa B/antagonistas & inibidores , Regiões Promotoras Genéticas , Biossíntese de Proteínas , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Transcrição Gênica
13.
Anal Biochem ; 219(2): 278-87, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8080084

RESUMO

An electrophoretic method is described for determining the molecular weight distribution of hyaluronan (HA). The method involves separation of HA by electrophoresis on a 0.5% agarose gel, followed by detection of HA using the cationic dye Stains-All (3,3'-dimethyl-9-methyl-4,5,4'5'-dibenzothiacarbocyanine). The recommended sample load is 7 micrograms. Calibration of the method with HA standards of known molecular weight has established a linear relationship between electrophoretic mobility and the logarithm of the weight-average molecular weight over the range of approximately 0.2-6 x 10(6). The separated HA pattern may also be visualized after electrotransfer of HA from the agarose gel to a nylon membrane. The membrane may be stained with the dye alcian blue. Alternatively, specific detection of HA from impure samples can be achieved by probing the nylon membrane with biotin-labeled HA-binding protein and subsequent interaction with a streptavidin-linked gold reagent and silver staining for amplification. The electrophoretic method was used to analyze HA in two different liquid connective tissues. Normal human knee joint synovial fluid showed a narrow HA molecular weight distribution, with a peak at 6-7 x 10(6). Owl monkey vitreous HA also showed a narrow molecular weight distribution, with a peak at 5-6 x 10(6). These results agree well with available published data and indicate the applicability of the method to the analysis of impure HA samples which may be available in limited amounts.


Assuntos
Eletroforese em Gel de Ágar/métodos , Ácido Hialurônico/química , Animais , Aotidae , Carbocianinas , Corantes , Densitometria/métodos , Humanos , Ácido Hialurônico/isolamento & purificação , Indicadores e Reagentes , Peso Molecular , Líquido Sinovial/química , Corpo Vítreo/química
14.
Arch Biochem Biophys ; 265(2): 484-95, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3421721

RESUMO

The potential for self-association by hyaluronate (HA) chains in 0.15 M NaCl was investigated, using low molecular weight HA segments as a model system. HA segments were derived from the polymer by controlled enzymatic digestion, and purified by gel filtration chromatography. Seven samples of narrow molecular weight distribution were analyzed by sensitivity-enhanced polyacrylamide gel electrophoresis, and found to have the following weight-average numbers of repeating disaccharide units: A, 90; B, 51; C, 38; D, 31; E, 23; F, 18; G, 13. The segment preparations were studied in 0.15 M NaCl by capillary viscometry, low angle laser light scattering, and circular dichroism spectroscopy. The data indicate concentration-dependent intermolecular association of short segments, and a capability for intramolecular association (hairpin formation) by larger HA segments.


Assuntos
Ácido Hialurônico , Cromatografia em Gel , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Humanos , Hialuronoglucosaminidase , Conformação Molecular , Espalhamento de Radiação , Cloreto de Sódio , Soluções , Viscosidade
15.
J Chromatogr ; 402: 149-58, 1987 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-3654861

RESUMO

High-performance gel permeation chromatography and sensitivity-enhanced polyacrylamide gel electrophoresis (SE-PAGE) have been combined to investigate the chromatographic properties of structurally related glycosaminoglycans. Enzymatically digested samples of hyaluronate, chondroitin 4-sulfate and dermatan sulfate were fractionated on a column series of TSK G4000SW and TSK G2000SW, eluted with 0.15 M sodium chloride. Isolated fractions were subjected to sensitivity-enhanced polyacrylamide gel electrophoresis for determination of molecular weight. These procedures allowed the rapid development of column calibration profiles for each glycosaminoglycan, under a given set of chromatographic conditions. The profiles obtained in 0.15 M sodium chloride yielded the following data: (1) at equal degrees of polymerization, hyaluronic acid chains have an apparently smaller hydrodynamic radius than the sulfated polymers, and (2) at equal molecular weights, all three glycosaminoglycans have approximately equal hydrodynamic radii.


Assuntos
Glicosaminoglicanos/análise , Cromatografia em Gel , Densitometria , Eletroforese em Gel de Poliacrilamida , Peso Molecular
16.
Anal Biochem ; 155(2): 275-85, 1986 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2425661

RESUMO

Oligomeric and polymeric fragments of glycosaminoglycans may be separated for rapid analysis by electrophoresis through a 10% polyacrylamide matrix. A ladder-like series of bands is observed, in which adjacent major bands correspond to species differing in chain length by one disaccharide unit. The component species are detected by a combined alcian blue and silver staining protocol. Detection limits are less than 50 ng per band, or approximately 2-5 micrograms total load for polydisperse samples. Densitometry of the stained gel may be used to determine molecular weight averages and distribution. The applicable molecular weight ranges are approximately 4000 to 100,000 for hyaluronate, or 1500 to 40,000 for chondroitin and dermatan sulfate samples of moderate charge density heterogeneity.


Assuntos
Azul Alciano , Glicosaminoglicanos/análise , Indóis , Prata , Eletroforese em Gel de Poliacrilamida , Ácido Hialurônico , Peso Molecular , Coloração e Rotulagem , Viscosidade
17.
Arch Biochem Biophys ; 237(1): 253-60, 1985 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-2578768

RESUMO

Sodium hyaluronate, digested with bovine testicular hyaluronidase, yielded a mixture of oligosaccharides with identical repeating disaccharide structures and differing molecular weights. The oligosaccharides were separated into a ladder-like series of bands by electrophoresis on a 10% polyacrylamide gel matrix. Coelectrophoresis of purified oligosaccharides has established that adjacent bands differ in chain length by one disaccharide unit. This procedure formed the basis for a rapid screening method in which the binding of cationic dyes by hyaluronate oligosaccharides may be assayed. As a function of chain length, the oligosaccharides showed a marked change in dye binding. Species containing less than seven repeating disaccharide units are not detected by any dye tested, even at very high sample loads. Larger oligosaccharides show an increase in dye binding. The chain length at which constant maximal dye binding is reached depends on the dye structure and solvent conditions, varying from approximately 12 to 30 disaccharide units. The hyaluronate fragments of sufficient chain length to duplicate polymer behavior should be useful models for the study of hyaluronate structure and interactions in solution.


Assuntos
Corantes/metabolismo , Ácido Hialurônico/metabolismo , Azul Alciano , Sítios de Ligação , Fenômenos Químicos , Química , Cromatografia em Gel , Densitometria , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Solventes , Coloração e Rotulagem
18.
Biochem J ; 221(3): 707-16, 1984 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-6433889

RESUMO

Oligosaccharide fragments of glycosaminoglycans may be separated for rapid analysis by electrophoresis through a 10% polyacrylamide matrix. An extensive ladder-like set of bands is observed for partial testicular hyaluronidase digests of chondroitin 4- or 6-sulphate, and for dermatan sulphate. Co-electrophoresis of purified oligosaccharides has established that the major bands of these patterns represent fragments differing in chain length by one disaccharide unit, with the smallest fragments having the greatest mobility. Additional minor bands, representing heterogeneity in the repeating unit structure, are also observed. There are slight differences in the mobilities of oligosaccharides derived from the three major types of sulphated glycosaminoglycans. Alcian Blue is employed for visualization of the digest fragments. Sample loads of 5-10 micrograms per band appear optimum. The smallest oligosaccharide which may be stained by this method is the hexasaccharide. After consideration of this effect, a good correlation is found to exist between densitometric scans of the gel-electrophoretic patterns and gel-filtration chromatographic profiles based on uronic acid concentration.


Assuntos
Sulfatos de Condroitina , Condroitina , Dermatan Sulfato , Eletroforese em Gel de Poliacrilamida/métodos , Oligossacarídeos/análise , Azul Alciano , Fenômenos Químicos , Química , Condroitina/análogos & derivados , Cromatografia em Gel , Hialuronoglucosaminidase
19.
Arch Biochem Biophys ; 230(1): 203-12, 1984 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6324681

RESUMO

The exchangeable amide protons of hyaluronic acid (HA) oligosaccharides and a higher-molecular-weight segment dissolved in H2O at pH 2.5 or 5.5 were examined by H NMR spectroscopy at 250 MHz. The HA segment preparation showed a single amide resonance, near the chemical shift for the amide proton of the monosaccharide 2-acetamido-2-deoxy-beta-D-glucopyranose (beta-GlcNAc). Smaller HA oligosaccharides showed two or three separate amide proton resonances, corresponding in relative peak area to interior or end GlcNAc residues. The interior GlcNAc amide resonance occurred at the same chemical shift as the single resonance of the HA segment. For the end GlcNAc residues, linkage to D-glucuronopyranose (GlcUA) through C1 resulted in an upfield shift relative to the beta-anomer of GlcNAc, whereas linkage through C3 resulted in a downfield shift relative to the corresponding anomer of GlcNAc. These chemical-shift perturbations appeared to be approximately offsetting in the case of linkage at both positions. The amide proton vicinal coupling constant (ca. 9 Hz) was found to be essentially independent of chain length, residue position, or solution pH. These data favor a nearly perpendicular orientation for the acetamido group with respect to the sugar ring, little affected by linkage of GlcNAc to GlcUA. No evidence for the existence of a stable hydrogen bond linking the amide proton with the carboxyl(ate) oxygen of the adjacent uronic acid residue was found. The amide proton resonances for chondroitin, chondroitin 4-sulfate, and dermatan sulfate were compared to that of HA. The chemical shifts of these resonances deviated no more than 0.1 ppm from that of HA. A small dependence on the identity of the adjacent uronic acid residue was noted, based on the observation of two resonances for dermatan sulfate.


Assuntos
Amidas , Glicosaminoglicanos , Ácido Hialurônico , Oligossacarídeos , Fenômenos Químicos , Química , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Prótons , Soluções
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