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1.
Int J Cardiol ; 380: 29-34, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36958397

RESUMO

Cardiac Rehabilitation (CR) has become an established intervention to support patient recovery after a cardiac event, with evidence supporting its effectiveness and cost-effectiveness in improving patient health and reducing future burden on healthcare systems. However, this evidence has focussed on the national value case for CR rather than at the point at which it is commissioned. This analysis uses the UK as a case-study to explore variation in current CR engagement and disassemble the value case from a commissioner perspective. Using data collected by the National Audit of CR (NACR), and an existing model of cost-effectiveness, we present details on the current level of CR uptake by commissioning region (Specialist Clinical Networks) in light of the current UK target of achieving 85% uptake. We then interrogate the value case for achieving the target at a commissioner level, highlighting the expected profile of health benefits and healthcare system costs over the long-term. Importantly we consider where this may differ from the national value case. Each commissioning region has a unique level of CR uptake and sociodemographic profile. Concurrently, the value case for commissioning CR relies on the upfront cost of the service being offset by long-term healthcare savings, and health improvements. The shift in the UK and internationally to more localised commissioning necessitates evidence of cost-effectiveness that better reflects the realities of those decision makers. This paper provides vital additional data to facilitate such commissioners to understand the value case in increasing CR uptake in line with national policy.


Assuntos
Reabilitação Cardíaca , Humanos , Atenção à Saúde , Reino Unido/epidemiologia , Análise Custo-Benefício
2.
Sci Total Environ ; 534: 4-13, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25557212

RESUMO

Transdisciplinary research, involving close collaboration between researchers and the users of research, has been a feature of environmental problem solving for several decades, often spurred by the need to find negotiated outcomes to intractable problems. In 2005, the Australian government allocated funding to its environment portfolio for public good research, which resulted in consecutive four-year programmes (Commonwealth Environmental Research Facilities, National Environmental Research Program). In April 2014, representatives of the funders, researchers and research users associated with these programmes met to reflect on eight years of experience with these collaborative research models. This structured reflection concluded that successful multi-institutional transdisciplinary research is necessarily a joint enterprise between funding agencies, researchers and the end users of research. The design and governance of research programmes need to explicitly recognise shared accountabilities among the participants, while respecting the different perspectives of each group. Experience shows that traditional incentive systems for academic researchers, current trends in public sector management, and loose organisation of many end users, work against sustained transdisciplinary research on intractable problems, which require continuity and adaptive learning by all three parties. The likelihood of research influencing and improving environmental policy and management is maximised when researchers, funders and research users have shared goals; there is sufficient continuity of personnel to build trust and sustain dialogue throughout the research process from issue scoping to application of findings; and there is sufficient flexibility in the funding, structure and operation of transdisciplinary research initiatives to enable the enterprise to assimilate and respond to new knowledge and situations.


Assuntos
Conservação dos Recursos Naturais/métodos , Ecologia , Comportamento Cooperativo , Pesquisa
3.
Lett Appl Microbiol ; 60(1): 20-6, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25284025

RESUMO

UNLABELLED: HOM6 is a major gene in the aspartate pathway which leads to biosynthesis of threonine and methionine. The phenotypes of the gene deletion mutant (hom6∆) in a variety of cultural conditions have previously provided meaningful insights into the biological roles of HOM6 and its upstream intermediate metabolites. Here, we conducted a survey on a spectrum of metal ions for their effect on the aspartate pathway and broader sulphur metabolism. We show that manganese (Mn(2+) ) promoted the growth of hom6∆ under both anaerobic and aerobic conditions. Unexpectedly, 4 mmol l(-1) hydrogen peroxide (H2 O2 ), a dose normally causing temporary cell growth arrest, enhanced the growth of hom6∆ under the anaerobic condition only, while it had no effect on the wild type strain BY4743. We propose that Mn(2+) and H2 O2 promote the growth of hom6∆ by reducing the accumulation of the toxic intermediate metabolite-aspartate ß-semialdehyde, via directing the aspartate pathway to the central sugar metabolism-tricarboxylic acid cycle. SIGNIFICANCE AND IMPACT OF THE STUDY: This study focuses on the yeast strain which lacks homoserine dehydrogenase encoded by HOM6 gene in aspartate metabolism. The HOM6-deletion mutant (hom6Δ) was analysed in the context of varying environmental parameters such as metal ions and oxidants, under anaerobic and aerobic conditions. We demonstrated that both manganese and hydrogen peroxide can promote the growth of hom6Δ, with the latter exerting such effect only under anaerobic condition. The findings are relevant to the research areas of ageing and anti-fungal drug development. It highlights the importance of interactions between gene expression and environmental factors as well as culture conditions.


Assuntos
Homosserina Desidrogenase/genética , Peróxido de Hidrogênio/farmacologia , Manganês/farmacologia , Metais/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Aerobiose , Anaerobiose , Ácido Aspártico/metabolismo , Meios de Cultura , Deleção de Genes , Redes e Vias Metabólicas/efeitos dos fármacos , Mutação , Oxidantes/farmacologia , Fenótipo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
4.
Free Radic Res ; 48(12): 1454-61, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25184342

RESUMO

Amino acid biosynthesis forms part of an integrated stress response against oxidants in Saccharomyces cerevisiae and higher eukaryotes. Here we show an essential protective role of the l-lysine biosynthesis pathway in response to the oxidative stress condition induced by the lipid oxidant-linoleic acid hydroperoxide (LoaOOH), by means of transcriptomic profiling and phenotypic analysis, and using the deletion mutant dal80∆ and lysine auxotroph lys1∆. A comprehensive up-regulation of lysine biosynthetic genes (LYS1, LYS2, LYS4, LYS9, LYS12, LYS20 and LYS21) was revealed in dal80Δ following the oxidant challenge. The lysine auxotroph (lys1∆) exhibited a significant decrease in growth compared with that of BY4743 upon exposure to LoaOOH, albeit with the sufficient provision of lysine in the medium. Furthermore, the growth of wild type BY4743 exposed to LoaOOH was also greatly reduced in lysine-deficient conditions, despite a full complement of lysine biosynthetic genes. Amino acid analysis of LoaOOH-treated yeast showed that the level of cellular lysine remained unchanged throughout oxidant challenge, suggesting that the induced lysine biosynthesis leads to a steady-state metabolism as compared to the untreated yeast cells. Together, these findings demonstrate that lysine availability and its biosynthesis pathway play an important role in protecting the cell from lipid peroxide-induced oxidative stress, which is directly related to understanding environmental stress and industrial yeast management in brewing, wine making and baking.


Assuntos
Ácidos Linoleicos/farmacologia , Peróxidos Lipídicos/farmacologia , Lisina/biossíntese , Estresse Oxidativo/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Perfilação da Expressão Gênica , Lisina/genética , Lisina/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética
5.
Free Radic Res ; 47(12): 1054-65, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24074273

RESUMO

Eukaryotic microorganisms are constantly challenged by reactive oxygen species derived endogenously or encountered in their environment. Such adversity is particularly applied to Saccharomyces cerevisiae under harsh industrial conditions. One of the major oxidants to challenge S. cerevisiae is linoleic acid hydroperoxide (LoaOOH). This study, which used genome-wide microarray analysis in conjunction with deletion mutant screening, uncovered the molecular pathways of S. cerevisiae that were altered by an arresting concentration of LoaOOH (75 µM). The oxidative stress response, iron homeostasis, detoxification through PDR transport and direct lipid ß-oxidation were evident through the induction of the genes encoding for peroxiredoxins (GPX2, TSA2), the NADPH:oxidoreductase (OYE3), iron uptake (FIT2, ARN2, FET3), PDR transporters (PDR5, PDR15, SNQ2) and ß-oxidation machinery (FAA2, POX1). Further, we discovered that Gpx3p, the dual redox sensor and peroxidase, is required for protection against LoaOOH, indicated by the sensitivity of gpx3Δ to a mild dose of LoaOOH (37.5 µM). Deletion of GPX3 conferred a greater sensitivity to LoaOOH than the loss of its signalling partner YAP1. Deletion of either of the iron homeostasis regulators AFT1 or AFT2 also resulted in sensitivity to LoaOOH. These novel findings for Gpx3p, Aft1p and Aft2p point to their distinct roles in response to the lipid peroxide. Finally, the expression of 89 previously uncharacterised genes was significantly altered against LoaOOH, which will contribute to their eventual annotation.


Assuntos
Ácidos Linoleicos/farmacologia , Peróxidos Lipídicos/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/genética , Expressão Gênica , Perfilação da Expressão Gênica/métodos , Análise de Sequência com Séries de Oligonucleotídeos , Estresse Oxidativo , Saccharomyces cerevisiae/metabolismo , Transdução de Sinais , Transcrição Gênica/efeitos dos fármacos
6.
J Mater Sci Mater Med ; 21(7): 2213-26, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20419389

RESUMO

A large number of cell types are known to respond to chemical and topographical patterning of substrates. Friction transfer of polytetrafluoroethylene (PTFE) onto substrates has been shown to produce continuous, straight, parallel nanofibres. Ammonia plasma treatment can be used to defluorinate the PTFE, decreasing the dynamic contact angle. Fibroblast and epithelial cells were elongated and oriented with their long axis parallel to the fibres, both individually and in clusters. The fibres restricted cell migration. Cell alignment was slightly reduced on the plasma-treated fibres. These results indicated that although surface topography can affect cellular response, surface chemistry also mediates the extent of this response.


Assuntos
Células Epiteliais/metabolismo , Fibroblastos/metabolismo , Osteoblastos/metabolismo , Politetrafluoretileno/metabolismo , Linhagem Celular , Movimento Celular , Células Cultivadas , Células Epiteliais/citologia , Células Epiteliais/ultraestrutura , Fibroblastos/citologia , Fibroblastos/ultraestrutura , Fricção , Gengiva/citologia , Humanos , Técnicas In Vitro , Nanofibras , Fatores de Tempo
7.
J Biomater Appl ; 24(5): 437-52, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19033327

RESUMO

Restenosis following percutaneous coronary intervention (PCI) is a considerable problem in long-term performance of cardiovascular stents, with a functional endothelial cell monolayer being important in its prevention. This study evaluates the influence of polymer coatings on human aortic endothelial cells (HAEC) and coronary artery smooth muscle cells (HCASMC) in vitro, in terms of morphology, cell number, and phenotype. It was demonstrated that the polymer coatings can be tailored to enhance adhesion and growth of HAECs whilst suppressing that of HCASMCs. It is concluded that one of the polymer coatings (BTL 01015) shows potential as a stent coating to enhance re-endothelialization.


Assuntos
Materiais Revestidos Biocompatíveis/química , Reestenose Coronária/prevenção & controle , Stents Farmacológicos , Polímeros/química , Adesão Celular , Contagem de Células , Células Cultivadas , Células Endoteliais/citologia , Humanos , Técnicas In Vitro , Teste de Materiais , Miócitos Cardíacos/citologia , Fenótipo
8.
J Appl Microbiol ; 102(3): 757-65, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17309625

RESUMO

AIMS: To investigate the influence of silica nanoparticles on the attachment and growth of Candida albicans cells. METHODS AND RESULTS: Spherical silica nanoparticles with diameters of 4, 7, 14 or 21 nm were attached to tissue culture polystyrene by a polycationic binding layer using a simple deposition procedure. The modified surfaces were shown to reduce the attachment and growth of C. albicans cells by a range of different measurements including microscopy, staining cells and measuring the amount of dye taken up and total cell activity measured using a dye reduction assay. For those cells that did attach and grow, the nanoparticle-coated surface inhibited the yeast to hyphal transition that is induced in the presence of serum. The greatest effect was observed for 7 and 14 nm diameter silica particles and we propose that the mechanism for these effects are related to either the topography of the surface or the slow dissolution of the bound silica. CONCLUSIONS: The attachment and growth of C. albicans is reduced by surface modification with silica nanoparticles. SIGNIFICANCE AND IMPACT OF THE STUDY: The modification of surfaces by nanoparticulate coatings is a simple process that may have applications in reducing the prevalence of Candida sp. cells on medical devices thus, limiting the incidence of this pathogenic yeast in clinical environments.


Assuntos
Candida albicans/fisiologia , Nanopartículas , Dióxido de Silício , Candida albicans/crescimento & desenvolvimento , Adesão Celular/fisiologia , Meios de Cultura , Indicadores e Reagentes/química , Microscopia de Força Atômica/métodos , Tamanho da Partícula , Poliestirenos , Sais de Tetrazólio/química
9.
Biomaterials ; 27(28): 4856-62, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16757021

RESUMO

Serum protein adsorption on colloidal silica surfaces was investigated using a quartz crystal microbalance with dissipation (QCM-D) monitoring. The amount of serum proteins adsorbed on colloidal silica-coated surfaces was not significantly different from the control silica surfaces, with the exception of 21nm colloidal silica which experienced significantly less (P<0.05) fibrinogen adsorption compared with control silica. The adhesion and proliferation of human endothelial cells (C11STH) on nano-scale colloidal silica surfaces were significantly reduced compared with control silica surfaces, suggesting that the conformation of adsorbed proteins on the colloidal silica surfaces plays a role in modulating the amount of cell binding. Fibronectin is one of the main extracellular matrix proteins involved in endothelial cell attachment to biomaterial surfaces. There was reduced binding of a monoclonal anti-fibronectin antibody, that reacted specifically with the cell-binding fragment, to fibronectin-coated colloidal silica surfaces compared with control silica surfaces. This suggests that the fibronectin adsorbed on the colloidal silica-coated surfaces was conformationally changed compared with control silica reducing the availability of the cell-binding domain of fibronectin.


Assuntos
Proteínas Sanguíneas/química , Proliferação de Células/efeitos dos fármacos , Nanoestruturas/química , Dióxido de Silício/farmacologia , Adsorção/efeitos dos fármacos , Animais , Adesão Celular/efeitos dos fármacos , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Fibronectinas/química , Humanos , Camundongos , Células NIH 3T3 , Nanotecnologia , Dióxido de Silício/química , Propriedades de Superfície
10.
J Evol Biol ; 19(1): 239-52, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16405595

RESUMO

Hybrid zones are natural laboratories offering insights into speciation processes. Narrow hybrid zones are less common in the sea than on land consistent with higher dispersal among marine populations. Acanthochromis polyacanthus is an unusual bony marine fish with philopatric dispersal that exists as allopatric stocks of white, bicoloured and black fish on the Great Barrier Reef (GBR). At two latitudes, different morphs coexist and hybridize at narrow contact zones. Sequence data from mitochondrial Hypervariable Region 1 revealed contrasting patterns of introgression across these zones. At the northern hybrid zone, a single clade of mitochondrial haplotypes was found in all white fish, hybrids and tens of kilometres into pure bicoloured stock. At the southern hybrid zone, there was no introgression of mitochondrial genes into black fish and hybrids shared the bicoloured haplotypes. Based on this asymmetry, we postulate that black fish from the southern GBR have experienced a selective sweep of their mitochondrial genome, which has resulted in almost total reproductive isolation.


Assuntos
Especiação Genética , Variação Genética , Genética Populacional , Hibridização Genética , Perciformes/genética , Animais , Análise por Conglomerados , DNA Mitocondrial/genética , Demografia , Geografia , Haplótipos/genética , Oceano Pacífico , Análise de Sequência de DNA
11.
J Mater Sci Mater Med ; 15(4): 355-9, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15332599

RESUMO

The current techniques used to create patterned materials at the nanometer scale such as electron beam lithography are restricted to patterning small areas, which can be expensive and time consuming. A simple, cost-effective approach has been developed to create a reproducible surface topography to influence the cellular response. In this study, the cellular response of murine fibroblasts to 7, 14 and 21 nm colloidal silica particles were investigated over one, three and seven days and up to seven weeks. The surface topography and wettability of the surfaces were also studied. The results confirmed that silica particles create a nanoscale topography, which initiates a distinctive cellular response affecting the morphology, adhesion and proliferation of the fibroblasts. The effect was evident up to seven weeks with no adverse effects on cell viability.


Assuntos
Técnicas de Cultura de Células/métodos , Materiais Revestidos Biocompatíveis/química , Fibroblastos/citologia , Fibroblastos/fisiologia , Nanotubos/química , Nanotubos/ultraestrutura , Dióxido de Silício/química , Animais , Adesão Celular , Divisão Celular , Linhagem Celular , Tamanho Celular , Sobrevivência Celular , Cristalização/métodos , Teste de Materiais , Camundongos , Tamanho da Partícula , Propriedades de Superfície
12.
J Mater Sci Mater Med ; 15(4): 507-11, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15332626

RESUMO

Characterisation and quantification of the surface energy of biomaterials used as tissue engineering scaffolds is important, but many of the techniques available to examine these properties are only applicable to smooth flat samples, not porous materials. This paper describes the application of the Washburn equation to measure the surface energy of a range of porous polyether polyurethane scaffolds with three test liquids; n-Hexane was used to measure a material constant, whilst ethanol and xylene were used to measure contact angles. The results show that the Washburn equation is not applicable in its current form, reasons for this could be that the voids in the materials are too wide for effective capillarity; absorption of the solvents into the polymer matrix may further complicate the measured imbibition profile. Another possible reason is the differences between the sizes of the interconnecting pores in scaffolds with varying void sizes; this could affect the capillary effect of the test liquids through the material. The repeatability of the results and the similar patterns observed with the different liquids suggest that if these issues could be quantified and incorporated into the Washburn equation, it may be possible to generate useful results for similar materials.


Assuntos
Algoritmos , Materiais Biocompatíveis/química , Teste de Materiais/métodos , Modelos Químicos , Poliuretanos/química , Água/química , Absorção , Simulação por Computador , Difusão , Etanol/química , Hexanos/química , Porosidade , Propriedades de Superfície , Xilenos/química
13.
Heart ; 89(2): 155-60, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12527665

RESUMO

OBJECTIVE: To investigate the effects of a 12 week comprehensive cardiac rehabilitation (CCR) programme on patients who have undergone implantation of an implantable cardioverter-defibrillator (ICD). DESIGN: Sixteen patients with ICDs (14 (88%) male, mean (SD) age 58 (10) years, range 34-74 years) were randomised to either attend an individually tailored CCR programme or receive usual care. They then changed to the alternative regimen for a further 12 weeks. Exercise capacity was assessed using a treadmill exercise test at baseline, after usual care, after CCR and 12 weeks after CCR to assess maintenance effects. Hospital anxiety and depression (HAD) scores were recorded at each stage. RESULTS: Exercise times (min:s; mean (SD)) increased by 16% from a baseline mean of 9:55 (2:33) to 11:11 (2:17) following attendance at CCR (95% confidence interval (CI) 0:34 to 1:58; p = 0.001). This improvement was maintained 12 weeks after attendance at CCR, at 11:20 (2:17) (p = 1.00). HAD scores for anxiety and depression decreased during CCR from a baseline of 13.4 (3.6) to 8.1 (3.6), 95% CI 3.5 to 7.0 (p < 0.001) and 9.9 (3.4) to 6.7 (2.9), 95% CI 1.9 to 4.4 (p = 0.002), respectively. These improvements were maintained at 12 weeks after CCR. No ventricular arrhythmias or ICD discharges occurred during the exercise components of the CCR. The total number of ventricular arrhythmias and ICD discharges was similar 12 weeks before, during, and 12 weeks after CCR. CONCLUSIONS: CCR appears to be safe for patients with ICDs. It can improve exercising ability and lower the levels of psychological distress. A larger multicentre study is recommended to confirm these findings.


Assuntos
Desfibriladores Implantáveis , Cardiopatias/reabilitação , Adolescente , Adulto , Idoso , Ansiedade/etiologia , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/prevenção & controle , Arritmias Cardíacas/psicologia , Depressão/etiologia , Exercício Físico/fisiologia , Teste de Esforço , Terapia por Exercício/métodos , Feminino , Cardiopatias/fisiopatologia , Cardiopatias/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Programas e Projetos de Saúde , Estudos Prospectivos , Disfunção Ventricular Esquerda/fisiopatologia
14.
Evolution ; 55(11): 2263-73, 2001 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-11794786

RESUMO

Acanthochromis polyacanthus is an unusual tropical marine damselfish that uniquely lacks pelagic larvae and has lost the capacity for broad-scale dispersal among coral reefs. On the modern Great Barrier Reef (GBR), three color morphs meet and hydridize at two zones of secondary contact. Allozyme electrophoreses revealed strong differences between morphs from the southern zone but few differences between morphs from the northern counterpart, thus suggesting different contact histories. We explore the phylogeography of Acanthochromis polyacanthus with mitochondrial cytochrome b region sequences (alignment of 565 positions) obtained from 126 individuals representing seven to 12 fish from 13 sites distributed over 12 reefs of the GBR and the Coral Sea. The samples revealed three major clades: (1) black fish collected from the southern GBR; (2) bicolored fish collected from the GBR and one reef (Osprey) from the northern Coral Sea; (3) black and white monomorphs collected from six reefs in the Coral Sea. All three clades were well supported (72-100%) by bootstrap analyses. Sequence divergences were very high between the major clades (mean = 7.6%) as well as within them (2.0-3.6%). Within clades, most reefs segregated as monophyletic assemblages. This was revealed both by phylogenetic analyses and AMOVAs that showed that 72-90% of the variance originated from differences among groups, whereas only 5-13% originated within populations. These patterns are discussed in relation to the known geological history of coral reefs of the GBR and the Coral Sea. Finally, we ask whether the monospecific status of Acanthochromis should be revisited because the sequence divergences found among our samples is substantially greater than those recorded among well-recognized species in other reef fishes.


Assuntos
Variação Genética , Perciformes/genética , Animais , Austrália , Grupo dos Citocromos b/genética , Mitocôndrias/química , Perciformes/classificação , Perciformes/fisiologia , Filogenia
15.
J Rheumatol ; 27(7): 1725-31, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10914859

RESUMO

OBJECTIVE: The specific objectives of this study using organ culture were (1) to transplant chondrocytes onto an intact cartilage surface; (2) to genetically modify endogenous and transplanted chondrocytes; and (3) to assess the ability of these cells to continually express a gene product. The specific objective with in vivo experiments was to transplant chondrocytes with intraarticular injections to cartilage. METHODS: Fluorescent membrane and intracellular dyes were used in conjunction with confocal microscopy to observe the integration of transplanted chondrocytes into cartilage both in vitro and in vivo. The distribution and duration of binding of rat, canine, and bovine chondrocytes to cartilage explants and the duration of expression of genes transduced into the transplanted chondrocytes were also determined. We used the vector AdlacZ, an E1 and E3 deleted replication defective adenoviral vector that contains the beta-galactosidase gene driven by the beta-actin promoter and the cytomegalovirus enhancer. RESULTS: The transplanted chondrocytes had a patchy distribution after in vitro or in vivo transplantation and buried themselves within the cartilage over time. Chondrocytes infected with the adenoviral vector AdlacZ soon or well after transplant to cartilage explants were maintained on the cartilage and continued throughout the duration of each trial to produce beta-galactosidase coded by the adenoviral vector. The cartilage plugs were infected with AdlacZ at 2 days or one, 2, 5, or 8 weeks after the chondrocytes were transplanted. The cartilage slices were then cultured from 15 days for chondrocytes infected at 8 weeks to 60 days for chondrocytes infected at 2 days post-transplant before determining the expression of beta-galactosidase. CONCLUSION: These results support the possibility of repairing cartilage by intraarticular injections of chondrocytes. Transduction of chondrocytes with genes producing a variety of matrix promoting proteins should further enhance the reconstruction of osteoarthritic cartilage.


Assuntos
Cartilagem/transplante , Condrócitos/transplante , Terapia Genética/métodos , Osteoartrite/terapia , Animais , Carbocianinas , Cartilagem/citologia , Cartilagem/metabolismo , Bovinos , Cães , Corantes Fluorescentes , Genes Reporter/genética , Injeções Intra-Articulares , Óperon Lac/genética , Osteoartrite/patologia , Osteoartrite/fisiopatologia , Transfecção
16.
Osteoarthritis Cartilage ; 7(5): 453-60, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10489317

RESUMO

Current therapies for osteoarthritis have been primarily directed at symptom relief rather than disease modification or cure. Improved understanding of cartilage biology and metabolism has permitted exploration of disease-modifying treatments for OA. Chondrocyte transplantation is one approach to disease modification that has received increasing attention. To date, most chondrocyte transplantation has focused on surgical implantation into isolated chondral defects.Our hypothesis is that cultured chondrocytes will preferentially transplant to hyaline cartilage after intraarticular injection. The purpose of this study was to quantify chondrocyte adherence to cartilage in an in-vitro bovine explant model under differing culture conditions. The effect on chondrocyte transplantation of time, of alginate vs. monolayer culture techniques, and of differing origin of tissue explants within the knee joint were assessed. The effect on transplantation of physically modifying the explant surface was also assessed. In addition to quantification of transplantation adherence, the morphology of transplanted chondrocytes was assessed with confocal and electron microscopy. Maximal adherence occurred by 24 h post-transplantation. Baseline transplant densities exceeding 1 x 10(6) cells/cm(2)were observed on unmodified cartilage surfaces. No significant differences in binding density were noted between cartilage explants obtained from the patella, femoral condyles, tibial plateaus or the trochlear groove. In addition, no differences in chondrocyte adherence were noted in cells cultured in monolayer or alginate beads. Transplanted chondrocytes were noted to be spherical irrespective of the culture methods employed. Notably, chondrocytes demonstrated significantly improved adherence to cartilage surfaces after the superficial layer was removed as compared to normal intact cartilage surfaces (increase of 26%, P< 0. 01). This suggests that chondrocytes may preferentially adhere to cartilage surfaces where the superficial layer has been damaged, as is the case in isolated chondral lesions, or with diffuse cartilage degeneration.


Assuntos
Cartilagem Articular/citologia , Condrócitos/transplante , Animais , Cartilagem Articular/metabolismo , Cartilagem Articular/ultraestrutura , Bovinos , Adesão Celular , Contagem de Células , Condrócitos/fisiologia , Condrócitos/ultraestrutura , Colágeno/metabolismo , Técnicas de Cultura , Microscopia Confocal , Microscopia Eletrônica de Varredura
17.
Osteoarthritis Cartilage ; 6(3): 153-9, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9682781

RESUMO

OBJECTIVE: We are attempting to genetically-modify chondrocytes transplanted to cartilage in vitro as a prelude to gene therapy trials in patients with osteoarthritis. DESIGN: With human cartilage and chondrocytes, we have explored the duration of binding of chondrocytes to cartilage in vitro and the expression of the beta-galactosidase gene introduced into the chondrocytes through infection with an adenoviral vector both before and after transplant of the chondrocytes to cartilage. RESULTS: Transplanted chondrocytes continued to bind to cartilage explants at 45 days in our longest trial. We could successfully infect chondrocytes with adenovirus at least 35 days after we transplanted the chondrocytes to cartilage. Expression of the beta-galactosidase gene continued throughout the duration of each trial. CONCLUSIONS: These results raise the possibility of repairing and rebuilding cartilage by resurfacing the cartilage with genetically modified chondrocytes. The ability to infect chondrocytes well after transplant raises the possibility of repeated infections of surface chondrocytes as an alternative to repeated injections of chondrocytes into the joint space.


Assuntos
Cartilagem Articular/citologia , Condrócitos/transplante , Osteoartrite/terapia , Adenoviridae , Adesão Celular , Expressão Gênica , Técnicas de Transferência de Genes , Terapia Genética , Vetores Genéticos , Humanos , Técnicas de Cultura de Órgãos , beta-Galactosidase/biossíntese , beta-Galactosidase/genética
18.
J Mater Sci Mater Med ; 9(1): 1-7, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15348695

RESUMO

There are many medical applications which benefit from the use of soluble biomaterials, including the sustained release of drugs over a precise period of time, or temporary conduits for controlling nerve regrowth. We have manufactured a series of phosphate-based controlled release glasses (CRGs) in which the solubility could be controlled by varying the concentration of CaO and Na2O. Fibres of the CRG containing iron and cerium were placed into direct contact with human neutrophils and macrophages in tissue culture for 2.5 and 24 h respectively and the responses analysed by scanning electron microscopy (SEM) and confocal microscopy. The supernatants were analysed for the cytokine IL-1beta by enzyme-linked immunosorbent assay (ELISA). Disks of CRG of various compositions were placed in contact with whole blood for 30 min and platelet adhesion assessed by SEM. Activation of platelets, granulocytes and complement were quantified by ELISA for beta-thromboglobulin, elastase and iC3b. Intrinsic coagulation activation was measured by timing the clotting of recalcified plasma. Only the cerium fibre inhibited IL-1beta release from macrophages. No platelet adhesion was observed to any disk composition. Three compositions containing MgO inhibited plasma clotting and showed an insignificant level of complement activation. This study has demonstrated the development of a number of compositions of CRG, which have great potential in a wide variety of biomedical applications.

19.
J Mater Sci Mater Med ; 9(12): 773-7, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15348938

RESUMO

Vesicoureteral reflux and urinary incontinence have previously been treated by various means including the endoscopic delivery of injectable bulking materials such as silicone micro-implants, PTFE implants, glass particles, fat and bovine collagen. These first three materials do not degrade and collagen requires frequently repeated injections in order to sustain the restored continence provided. Vesicoureteric reflux in children usually resolves independently before the age of five. Correction is required before this, because treatment by prophylactic antibiotics is frequently unsuccessful in preventing breakthrough infection. The ideal material for injection should have large particles to avoid migration, inject easily and controllably, be non-toxic and dissolve over the period of time by which time the kidney will be mature. Three different controlled-release glass (CRG) granule compositions have been prepared by Giltech Ltd, and suspended in a suitable carrier medium (in this case glycerol). The degradable glasses, which have two different size ranges of 200-300 and <53 microm, and three different solution rates, were injected intramuscularly into the dorso-lumbar region of rats. Histological analysis of cryostat cut section after time periods of 2 d, 4 and 9 wk, and 6 mon has been performed. Histology sections were stained for neutrophils and macrophages using enzyme histochemistry. ED1 (monocytes and immature macrophages), ED2 (mature tissue macrophages), CD4 (helper/inducer T-lymphocytes and macrophages), CD8 (suppressor/cytotoxic T-lymphocytes), Interleukin-1beta, IL-2 (activated T-lymphocytes), Major Histocompatibility Complex (MHC) class II (activated macrophages and activated B-lymphocytes), alpha-beta (T-lymphocytes) and CD45RA (B lymphocytes) antibodies have been used to stain immunohistochemically each sample. This study demonstrates that particulate, degrading glass is stimulating an inflammatory response in soft tissue at time periods up to 6 mon. It should be noted that very small particulate, fast degrading glass is leading to tissue necrosis and should not be considered further for these applications. However, larger particulate, slower degrading materials are demonstrating effective potential for stress incontinence applications.

20.
J Rheumatol ; 24(7): 1396-402, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9228144

RESUMO

OBJECTIVE: To determine the level of T cell clonal expansion and the proportion of T cells that persist over time in the synovial fluid (SF) of patients with juvenile onset rheumatoid arthritis (JRA). METHODS: We collected SF samples from each of 3 patients with JRA at 2 to 3 year intervals. To measure expression across the entire spectrum of Vbeta families in each of 7 fluids examined, we synthesized and amplified dscDNA from all 24 Vbeta families with a single reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: The proportion of clonally expanded T cells and persistent T cells is low and variable among patients. CONCLUSION: The data are supportive of disease models not centered on T cells but centered on the changing nature of the disease over time.


Assuntos
Artrite Juvenil/imunologia , Receptores de Antígenos de Linfócitos T/genética , Líquido Sinovial/química , Líquido Sinovial/imunologia , Idade de Início , Processamento Alternativo/fisiologia , Artrite Juvenil/genética , Sequência de Bases , Clonagem Molecular , Humanos , Região Variável de Imunoglobulina/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Subpopulações de Linfócitos T/química , Subpopulações de Linfócitos T/imunologia
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