Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 149
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Acta Biomater ; 170: 453-463, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37652212

RESUMO

Generation of protective immunity through vaccination arises from the adaptive immune response developed primarily in the lymph nodes drained from the immunization site. Relative to the intramuscular route, subcutaneous administration allows for direct and rapid access to the lymphatics, but accumulation of soluble protein antigens within the lymph nodes is limited. Subunit vaccines also require immune stimulating adjuvants which may not accumulate in the same lymph nodes simultaneously with antigen. Herein we report the use of biotinylated poly (lactic-co-glycolic acid) nanoparticles (bNPs) to enhance delivery of a model protein antigen to the lymphatics. bNPs provide dual functionality as adjuvant and vehicle to localize antigens with stimulated immune cells in the same draining lymph node. Using streptavidin as a model antigen, which can be loaded directly onto the bNP surface, we evaluated the kinetics of lymph node occupancy and adaptive immune responses in wildtype C57BL/6 mice. Antigen exposure in vivo was significantly improved through surface loading onto bNPs, and we developed a working kinetic model to account for the retention of both particles and antigen in draining lymph nodes. We observed enhanced T cell responses and antigen-specific B cell response in vivo when antigen was delivered on the particle surface. This work highlights the advantage of combining intrinsic adjuvant and antigen loading in a single entity, and the utility of kinetic modeling in the understanding of particle-based vaccines. STATEMENT OF SIGNIFICANCE: Development of safe and effective subunit vaccines depends on effective formulations that render optimized exposure and colocalization of antigens and adjuvants. In this work, we utilize a nanoparticle system which features self-adjuvanting properties and allows for surface loading of recombinant protein antigens. Using in vivo imaging, we demonstrated prolonged co-localization of the antigen and adjuvant particles in draining lymph nodes and provided evidence of B cell activation for up to 21 days following subcutaneous injection. A pharmacokinetic model was developed as a step towards bridging the translational gap between particulate-based vaccines and observed outcomes. The results have implications for the rational design of particle-based vaccines.

2.
Mol Pharm ; 19(7): 2638-2650, 2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35621214

RESUMO

Nanoparticle formulations have long been proposed as subunit vaccine carriers owing to their ability to entrap proteins and codeliver adjuvants. Poly(lactic-co-glycolic acid) (PLGA) remains one of the most studied polymers for controlled release and nanoparticle drug delivery, and numerous studies exist proposing PLGA particles as subunit vaccine carriers. In this work we report using PLGA nanoparticles modified with biotin (bNPs) to deliver proteins via adsorption and stimulate professional antigen-presenting cells (APCs). We present evidence showing bNPs are capable of retaining proteins through the biotin-avidin interaction. Surface accessible biotin bound both biotinylated catalase (bCAT) through avidin and streptavidin horseradish peroxidase (HRP). Analysis of the HRP found that activity on the bNPs was preserved once captured on the surface of bNP. Further, bNPs were found to have self-adjuvant properties, evidenced by bNP induced IL-1ß, IL-18, and IL-12 production in vitro in APCs, thereby licensing the cells to generate Th1-type helper T cell responses. Cytokine production was reduced in avidin precoated bNPs (but not with other proteins), suggesting that the proinflammatory response is due in part to exposed biotin on the surface of bNPs. bNPs injected subcutaneously were localized to draining lymph nodes detectable after 28 days and were internalized by bronchoalveolar lavage dendritic cells and macrophages in mice in a dose-dependent manner when delivered intranasally. Taken together, these data provide evidence that bNPs should be explored further as potential adjuvanting carriers for subunit vaccines.


Assuntos
Biotina , Nanopartículas , Adjuvantes Imunológicos/química , Animais , Avidina , Células Dendríticas , Camundongos , Nanopartículas/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Vacinas de Subunidades Antigênicas/metabolismo
3.
NMR Biomed ; 33(5): e4258, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32066202

RESUMO

Metabolic heart disease (MHD), which is strongly associated with heart failure with preserved ejection fraction, is characterized by reduced mitochondrial energy production and contractile performance. In this study, we tested the hypothesis that an acute increase in ATP synthesis, via short chain fatty acid (butyrate) perfusion, restores contractile function in MHD. Isolated hearts of mice with MHD due to consumption of a high fat high sucrose (HFHS) diet or on a control diet (CD) for 4 months were studied using 31 P NMR spectroscopy to measure high energy phosphates and ATP synthesis rates during increased work demand. At baseline, HFHS hearts had increased ADP and decreased free energy of ATP hydrolysis (ΔG~ATP ), although contractile function was similar between the two groups. At high work demand, the ATP synthesis rate in HFHS hearts was reduced by over 50%. Unlike CD hearts, HFHS hearts did not increase contractile function at high work demand, indicating a lack of contractile reserve. However, acutely supplementing HFHS hearts with 4mM butyrate normalized ATP synthesis, ADP, ΔG~ATP and contractile reserve. Thus, acute reversal of depressed mitochondrial ATP production improves contractile dysfunction in MHD. These findings suggest that energy starvation may be a reversible cause of myocardial dysfunction in MHD, and opens new therapeutic opportunities.


Assuntos
Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/biossíntese , Butiratos/farmacologia , Doenças Cardiovasculares/metabolismo , Doenças Metabólicas/metabolismo , Mitocôndrias Cardíacas/metabolismo , Contração Miocárdica/efeitos dos fármacos , Animais , Doenças Cardiovasculares/diagnóstico por imagem , Doenças Cardiovasculares/fisiopatologia , Metabolismo Energético/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Hidrólise , Espectroscopia de Ressonância Magnética , Masculino , Doenças Metabólicas/diagnóstico por imagem , Doenças Metabólicas/fisiopatologia , Camundongos Endogâmicos C57BL , Mitocôndrias Cardíacas/efeitos dos fármacos , Termodinâmica
4.
Psychoneuroendocrinology ; 104: 276-285, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30917336

RESUMO

BACKGROUND: Hypothalamic-pituitary-adrenocortical (HPA) axis dysregulation is associated with disease and may be indexed by poor cortisol habituation (i.e., a failure to show decreased responding with repeated stressor exposure). Thus, stress management training that can enhance HPA axis habituation may benefit health. To date, the effects of Mindfulness Based Stress Reduction (MBSR) and Cognitive Behavioral Therapy (CBT) interventions on HPA axis habituation remain untested. To test the effects of MBSR and CBT on HPA axis habituation, the present study used a parallel arm randomized controlled trial. METHODS: Healthy adults reporting moderate-to-high stress (n = 138) were randomly assigned to a 6-week MBSR intervention, a 6-week CBT intervention, or Waitlist control group. Post-intervention, participants completed a social-evaluative performance stressor during each of two laboratory visits scheduled 48-h apart. Salivary cortisol was collected pre-stressor, and 25, 35, and 60 min post-stressor onset during each visit. Final analyses included 86 participants who completed procedures up to the first laboratory visit. RESULTS: Relative to the control condition, both MBSR and CBT groups showed greater cortisol habituation. The MBSR group exhibited marginally greater habituation than the Waitlist group in cortisol samples corresponding to the recovery time points (35 and 60 min post-stressor onset). In contrast, the CBT group showed greater habituation than the Waitlist across all sampling timepoints collected (pre-stressor, 25, 35, and 60 min post-stressor onset). Yet, the CBT group also demonstrated elevated pre-stressor cortisol during the first visit. CONCLUSIONS: Results suggest that MBSR and CBT interventions promote greater HPA axis habituation relative to no training, but do not reduce overall cortisol output (i.e., across both visits). Observed differences between CBT and MBSR training in relation to cortisol habituation are discussed.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Habituação Psicofisiológica/fisiologia , Atenção Plena/métodos , Adulto , Feminino , Humanos , Hidrocortisona/análise , Hidrocortisona/metabolismo , Sistema Hipotálamo-Hipofisário/química , Masculino , Sistema Hipófise-Suprarrenal/química , Saliva/química , Estresse Psicológico/psicologia , Estresse Psicológico/terapia
5.
Am J Cardiovasc Drugs ; 18(1): 25-36, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29080984

RESUMO

Preparations from Crataegus (hawthorn) have a long history in the treatment of heart failure. WS 1442 is a dry extract from hawthorn leaves with flowers (4-6.6:1), extraction solvent of ethanol 45% (w/w), adjusted to 17.3-20.1% of oligomeric procyanidins. Nonclinical studies show that WS 1442 has positive inotropic and antiarrhythmic properties and protects the myocardium from ischemic damage, reperfusion injury, and hypertension-related hypertrophy, improves endothelial functions such as NO synthesis, and delays endothelial senescence. Randomized, controlled trials in patients with heart failure have demonstrated that the herbal medicinal product increases functional capacity, alleviates disabling symptoms, and improves health-related quality of life, all of which have become important targets of heart failure therapy according to current disease management guidelines. Clinical trials (including a 2-year mortality study with polypharmacy and > 1300 patients exposed) and post-marketing surveillance studies have shown that WS 1442 has a very favorable safety profile both as monotherapy and as add-on therapy, where no drug interactions have been observed. No specific adverse reactions to WS 1442 are known to date. WS 1442 may thus help to close the therapeutic gap between systolic and diastolic heart failure for which evidence of efficacy for other cardioactive drugs is sparse. Scientific evidence shows that WS 1442 is safe and has a beneficial effect in patients with heart failure corresponding to New York Heart Association classes II or III. The benefit-risk assessment for WS 1442 is therefore positive.


Assuntos
Medicina Baseada em Evidências/métodos , Flavonoides/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Fitoterapia/métodos , Extratos Vegetais/uso terapêutico , Cardiotônicos/efeitos adversos , Cardiotônicos/uso terapêutico , Crataegus/efeitos adversos , Flavonoides/efeitos adversos , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/mortalidade , Humanos , Mortalidade/tendências , Estudos Multicêntricos como Assunto/métodos , Fitoterapia/efeitos adversos , Extratos Vegetais/efeitos adversos , Medição de Risco
6.
J Wound Care ; 26(8): 508-513, 2017 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-28795880

RESUMO

OBJECTIVE: A pilot single-blinded randomised controlled trial (RCT) was conducted to examine concordance with and acceptability of electric stimulation therapy (EST) in patients with venous leg ulcers (VLUs) who had not tolerated moderate to high compression. METHOD: Participants were randomised to the intervention group (n=15) or a placebo control group (n=8) in which EST was used four times daily for 20 minutes per session. Participants were monitored for eight weeks during which time concordance with the treatment and perceptions of the treatment were assessed. RESULTS: Concordance with the total recommended treatment time was 71.4% for the intervention group and 82.9% for the control group; a difference that was not statistically significant. Participants rated EST as acceptable (84.6% intervention; 83.3% control), only two participants, both from the placebo control group, would not be willing to use EST again. The majority considered EST easier to use than compression (68.4%). CONCLUSION: EST was a practical and acceptable treatment among people who have been unable to tolerate moderate to high compression therapy.


Assuntos
Terapia por Estimulação Elétrica/métodos , Aceitação pelo Paciente de Cuidados de Saúde , Úlcera Varicosa/terapia , Idoso , Idoso de 80 Anos ou mais , Bandagens Compressivas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Método Simples-Cego
7.
J Dairy Sci ; 100(6): 4365-4376, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28365110

RESUMO

To test the hypothesis that the metabolism of Cu in dairy cows is affected by basal forage and added S and Mo, 56 dairy cows that were 35 (standard error ± 2.2) days postcalving and yielding 38.9 kg of milk/d (standard error ± 0.91) were offered 1 of 4 diets in a 2 × 2 factorial design for a 14-wk period. The 4 diets contained approximately 20 mg of Cu/kg of dry matter (DM), and had a corn silage-to-grass silage ratio of 0.75:0.25 (C) or 0.25:0.75 (G) and were either unsupplemented (-) or supplemented (+) with an additional 2 g of S/kg of DM and 6.5 mg of Mo/kg of DM. We found an interaction between forage source and added S and Mo on DM intake, with cows offered G+ having a 2.1 kg of DM lower intake than those offered G-, but no effect on the corn silage-based diets. Mean milk yield was 38.9 kg/d and we observed an interaction between basal forage and added S and Mo, with yield being decreased in cows offered G+ but increased on C+. No effect of dietary treatment on milk composition or live weight was noted, but body condition was lower in cows fed added S and Mo irrespective of forage source. We found an interaction between forage source and added S and Mo on milk somatic cell count, which was higher in cows offered G+ compared with G-, but not in cows fed the corn silage-based diets, although all values were low (mean values of 1.72, 1.50, 1.39, and 1.67 log10/mL for C-, C+, G-, and G+, respectively). Mean plasma Cu, Fe, and Mn concentrations were 13.8, 41.3, and 0.25 µmol/L, respectively, and were not affected by dietary treatment, whereas plasma Mo was 0.2 µmol/L higher in cows receiving added S and Mo. The addition of dietary S and Mo decreased liver Cu balance over the study period in cows fed either basal forage, but the decrease was considerably greater in cows receiving the grass silage-based diet. Similarly, hepatic Fe decreased more in cows receiving G than C when S and Mo were included in the diet. We concluded that added S and Mo reduces hepatic Cu reserves irrespective of basal forage source, but this decrease is considerably more pronounced in cows receiving grass silage- than corn silage-based rations and is associated with a decrease in intake and milk performance and an increase in milk somatic cell count.


Assuntos
Cobre/administração & dosagem , Cobre/metabolismo , Fígado/metabolismo , Molibdênio/administração & dosagem , Silagem , Enxofre/administração & dosagem , Criação de Animais Domésticos , Animais , Peso Corporal , Bovinos , Feminino , Leite/química , Leite/citologia , Poaceae , Zea mays
8.
J Wound Care ; 26(3): 88-98, 2017 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-28277996

RESUMO

OBJECTIVE: Compression therapy is a gold standard treatment to promote venous leg ulcer (VLU) healing. Concordance with compression therapy is, however, often sub-optimal. The aim of this study was to evaluate the effectiveness of electric stimulation therapy (EST) to facilitate healing of VLUs among people who do not use moderate-to-high levels of compression (>25 mmHg). METHOD: A pilot multicentre, single-blinded randomised controlled trial was conducted. Participants were randomised (2:1) to the intervention group or a control group where EST or a sham device was used 4 times daily for 20 minutes per session. Participants were monitored fortnightly for eight weeks. The primary outcome measure was percentage of area (wound size) change. RESULTS: In the 23 patients recruited, an average redution in wound size of 23.15% (standard deviation [SD]: 61.23) was observed for the control group compared with 32.67 % (SD: 42.54) for the intervention. A moderate effect size favouring the intervention group was detected from univariate [F(1,18)=1.588, p=0.224, partial eta squared=0.081] and multivariate repeated measures [F(1,18)=2.053, p=0.169, partial eta squared=0.102] analyses. CONCLUSION: The pilot study was not powered to detect statistical significance, however, the difference in healing outcomes are encouraging. EST may be an effective adjunct treatment among patients who have experienced difficulty adhering to moderate-to-high levels of compression therapy.


Assuntos
Terapia por Estimulação Elétrica , Úlcera da Perna/terapia , Meias de Compressão , Úlcera Varicosa/terapia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Método Simples-Cego , Cicatrização
9.
Elife ; 52016 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-27441501

RESUMO

Understanding the neural basis of behaviour requires studying brain activity in behaving subjects using complementary techniques that measure neural responses at multiple spatial scales, and developing computational tools for understanding the mapping between these measurements. Here we report the first results of widefield imaging of genetically encoded calcium indicator (GCaMP6f) signals from V1 of behaving macaques. This technique provides a robust readout of visual population responses at the columnar scale over multiple mm(2) and over several months. To determine the quantitative relation between the widefield GCaMP signals and the locally pooled spiking activity, we developed a computational model that sums the responses of V1 neurons characterized by prior single unit measurements. The measured tuning properties of the GCaMP signals to stimulus contrast, orientation and spatial position closely match the predictions of the model, suggesting that widefield GCaMP signals are linearly related to the summed local spiking activity.


Assuntos
Comportamento Animal , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Cálcio/análise , Imagem Óptica/métodos , Animais , Simulação por Computador , Genes Reporter , Macaca
10.
Int J Obes (Lond) ; 40(10): 1515-1522, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27457416

RESUMO

OBJECTIVE: Large portions of energy-dense foods drive energy intake but the brain mechanisms underlying this effect are not clear. Our main objective was to investigate brain function in response to food images varied by portion size (PS) and energy density (ED) in children using functional magnetic resonance imaging (fMRI). METHODS AND DESIGN: Blood-oxygen-level-dependent (BOLD) fMRI was completed in 36 children (ages 7-10 years) after a 2-h fast while viewing food images at two levels of PS (Large PS, Small PS) and two levels of ED (High ED, Low ED). Children rated perceived fullness pre- and post-fMRI, as well as liking of images on visual analog scales post-fMRI. Anthropometrics were completed 4 weeks before the fMRI. Large PS vs Small PS and High ED vs Low ED were compared with region-of-interest analyses using Brain Voyager v 2.8. RESULTS: Region-of-interest analyses revealed that activation in the right inferior frontal gyrus (P=0.03) was greater for Large PS vs Small PS. Activation was reduced for High ED vs Low ED in the left hypothalamus (P=0.03). Main effects were no longer significant after adjustment for pre-fMRI fullness and liking ratings (PS, P=0.92; ED, P=0.58). CONCLUSION: This is the first fMRI study to report increased activation to large portions in a brain region that is involved in inhibitory control. These findings may contribute to understanding why some children overeat when presented with large portions of palatable food.


Assuntos
Regulação do Apetite/fisiologia , Ingestão de Energia/fisiologia , Comportamento Alimentar/fisiologia , Preferências Alimentares/psicologia , Hipotálamo/fisiologia , Obesidade Infantil/fisiopatologia , Tamanho da Porção/psicologia , Mapeamento Encefálico , Criança , Comportamento de Escolha/fisiologia , Sinais (Psicologia) , Jejum , Feminino , Alimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Obesidade Infantil/prevenção & controle , Obesidade Infantil/psicologia , Percepção , Estimulação Luminosa , Estados Unidos
11.
Stress ; 18(5): 554-60, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26119263

RESUMO

Ruminative thought about stressors has been linked to extended post-stressor cardiovascular activation, which in turn predicts negative long-term health outcomes. Past work indicates that the nature of thought (mental imagery or verbal thought) may shape cardiovascular responses. Some evidence suggests that individuals with rumination tendencies may be especially vulnerable to stress-related cardiovascular activation, although it is unclear to what extent type of thought (imagery or verbal thought) influences this relationship. This study included a laboratory stressor followed by a stressor recall task in which mentation type was manipulated. Healthy undergraduate students (N = 138; 47% female) underwent a speech stressor and then were randomly assigned to complete a stressor recall task using either mental imagery or verbal-linguistic mentation. Heart rate (HR) and blood pressure (BP) were measured throughout. Self-report trait rumination was measured at baseline. Results indicated that trait rumination and mentation type interacted to predict HR. Individuals with high trait rumination scores had significantly greater increases in HR during the verbal-linguistic conditions compared to the mental imagery conditions. There were no mentation type differences in the low trait ruminators, no differences in BP and no main effects of trait rumination. Results suggest that mentation type may be a key in understanding the relationship between rumination and cardiovascular activation, especially for trait ruminators.


Assuntos
Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Imaginação/fisiologia , Rememoração Mental/fisiologia , Personalidade , Estresse Psicológico/fisiopatologia , Pensamento , Adolescente , Feminino , Humanos , Masculino , Autorrelato , Fala , Adulto Jovem
12.
J Psychiatr Ment Health Nurs ; 22(7): 491-501, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25990303

RESUMO

Delays in effective treatment of a first episode psychosis can result in more severe symptoms, a longer time to achieve symptom control and a poorer quality of life; yet around 40% do not take antipsychotic medication as prescribed. There is evidence that patients and staff have different perceptions of what affects adherence with medication. Research in adults suggests healthcare professionals and patients understand the importance of good insight in promoting adherence with medication for schizophrenia; however, healthcare staff may overestimate the impact of side effects and underestimate the importance of medication effectiveness. There is also some evidence to suggest that motivations to take prescribed medication may differ in first and multi-episode psychosis. This research therefore sought views of staff working with adolescents diagnosed with first episode psychosis about what factors affected adherence with antipsychotic medication. Staff responding to the survey felt that young people were more likely to take medication if they felt it would make them better, prevent relapse and if they had a positive rapport with staff. As in an adult population, side effects, particularly weight gain, sedation and muscular side effects, were expressed as a common reason for poor adherence. Doctors and nurses assigned differing importance to parameters such as family views of medication, fear of admission and a preference for cannabis over medication suggesting that views may differ between professional groups Views of young people will be obtained in the next phase of the research study to enable comparison with staff views and consideration of staff interventions to better promote medication adherence. Antipsychotic medication is an effective treatment for first episode psychosis; yet 40% of patients do not take medication as prescribed. Previous research in adults with schizophrenia comparing healthcare professional and patient views suggests that while healthcare professionals recognize the importance of insight in promoting medication adherence, they underestimate the importance of medication efficacy and overestimate the impact of side effects. It was hypothesized that staff in this study would also recognize the importance of insight and positive medication attitudes in teenagers with psychosis, but overestimate the impact of side effects on medication adherence. This cross-sectional observational study sought staff views about factors affecting antipsychotic medication adherence in those aged between 14 and 18 years. An online survey was distributed and 60 responses were subsequently returned. Staff felt that good medication insight as well as positive relationships with staff were important determinants of good medication adherence. The most important influences of poor adherence were poor insight, side effects of medication and a wish to exert personal control around medication decisions. The results therefore confirmed the initial hypothesis. Published literature also provides support for some, but not all, of the staff views expressed in survey responses.


Assuntos
Comportamento do Adolescente , Antipsicóticos/uso terapêutico , Atitude do Pessoal de Saúde , Adesão à Medicação , Transtornos Psicóticos/tratamento farmacológico , Adolescente , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
14.
Stress Health ; 30(3): 188-97, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25100270

RESUMO

Psychological detachment from work is important for facilitating recovery. This can be threatened by rumination, or thinking about the day's stressors. Rumination may lead to distress, fatigue and extended activation of stress-related systems, but findings are not unequivocal. Level of construal (abstract or concrete) and type of mentation (imagery or verbal thought) used during stressor-focused rumination may shape physiological and affective responses and impact recovery. This study tested whether blood pressure (BP) and anxiety responses to stressor-focused rumination differ by mentation type and construal level. Healthy undergraduates (n = 136) performed a speech stressor and then completed a rumination task in one of four randomly assigned conditions: concrete imagery, abstract imagery, concrete verbal thought or abstract verbal thought. Anxiety and continuous BP were assessed. Concrete rumination led to greater BP, whereas rumination with abstract construals led to lower BP. Furthermore, participants in the abstract conditions had greater increases in anxiety following stressor-focused rumination than in the concrete conditions. Results suggest that the immediate physiological and psychological consequences of stressor-focused rumination depend upon mode of thought.


Assuntos
Afeto/fisiologia , Pressão Sanguínea/fisiologia , Estresse Psicológico/psicologia , Pensamento/fisiologia , Análise de Variância , Ansiedade/etiologia , Ansiedade/fisiopatologia , Feminino , Humanos , Imaginação/fisiologia , Masculino , Rememoração Mental/fisiologia , Desempenho Psicomotor/fisiologia , Autoeficácia , Estresse Psicológico/fisiopatologia , Adulto Jovem
15.
Eur J Cancer ; 50(8): 1430-6, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24582914

RESUMO

BACKGROUND: RAS mutations predict resistance to anti-epidermal growthfactor receptor (EGFR) monoclonal antibodies in metastatic colorectal cancer. We analysed RAS mutations in 30 non-metastatic rectal cancer patients treated with or without cetuximab within the 31 EXPERT-C trial. METHODS: Ninety of 149 patients with tumours available for analysis were KRAS/BRAF wild-type, and randomly assigned to capecitabine plus oxaliplatin (CAPOX) followed by chemoradiotherapy, surgery and adjuvant CAPOX or the same regimen plus cetuximab (CAPOX-C). Of these, four had a mutation of NRAS exon 3, and 84 were retrospectively analysed for additional KRAS (exon 4) and NRAS (exons 2/4) mutations by using bi-directional Sanger sequencing. The effect of cetuximab on study end-points in the RAS wild-type population was analysed. RESULTS: Eleven (13%) of 84 patients initially classified as KRAS/BRAF wild-type were found to have a mutation in KRAS exon 4 (11%) or NRAS exons 2/4 (2%). Overall, 78/149 (52%) assessable patients were RAS wild-type (CAPOX, n=40; CAPOX-C, n=38). In this population, after a median follow-up of 63.8months, in line with the initial analysis, the addition of cetuximab was associated with numerically higher, but not statistically significant, rates of complete response (15.8% versus 7.5%, p=0.31), 5-year progression-free survival (75.5% versus 67.5%, hazard ratio (HR) 0.61, p=0.25) and 5-year overall survival (83.8% versus 70%, HR 0.54, p=0.20). CONCLUSIONS: RAS mutations beyond KRAS exon 2 and 3 were identified in 17% of locally advanced rectal cancer patients. Given the small sample size, no definitive conclusions on the effect of additional RAS mutations on cetuximab treatment in this setting can be drawn and further investigation of RAS in larger studies is warranted.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mutação , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/genética , Proteínas ras/genética , Adulto , Idoso , Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Capecitabina , Cetuximab , Quimiorradioterapia , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/análogos & derivados , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem , Oxaliplatina , Neoplasias Retais/mortalidade , Estudos Retrospectivos , Análise de Sequência de DNA , Análise de Sobrevida , Resultado do Tratamento
16.
J Hum Nutr Diet ; 27(3): 207-18, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24313460

RESUMO

BACKGROUND: Crohn's disease is a debilitating chronic inflammatory bowel disease. Appropriate use of diet and nutritional therapy is integral to the overall management strategy of Crohn's disease. The aim was to develop evidence-based guidelines on the dietary management of Crohn's disease in adults. METHODS: Questions relating to the dietary management of Crohn's disease were developed. These included the roles of enteral nutrition to induce remission, food re-introduction diets to structure food re-introduction and maintain remission, and dietary management of stricturing disease, as well as whether probiotics or prebiotics induce or maintain remission. A comprehensive literature search was conducted and relevant studies from January 1985 to November 2009 were identified using the electronic database search engines CINAHL, Cochrane Library, EMBASE, MEDLINE, Scopus and Web of Science. Evidence statements, recommendations, practical considerations and research recommendations were developed. RESULTS: Fifteen research papers were critically appraised and the evidence formed the basis of these guidelines. Although corticosteroids appear to be more effective, enteral nutrition (elemental or non-elemental) can be offered as an alternative option to induce disease remission. After a course of enteral nutrition, food re-introduction diets may be useful to structure food re-introduction and help maintain disease remission. Dietary fibre is contraindicated in the presence of strictures as a result of the risk of mechanical obstruction. The use of probiotics and prebiotics is not currently supported. CONCLUSIONS: As an alternative to corticosteroids, evidence supports enteral nutrition to induce disease remission. Food re-introduction diets provide structure to food re-introduction and help maintain disease remission. These guidelines aim to reduce variation in clinical practice.


Assuntos
Doença de Crohn/dietoterapia , Corticosteroides/uso terapêutico , Fibras na Dieta/administração & dosagem , Dietética , Nutrição Enteral , Medicina Baseada em Evidências , Humanos , MEDLINE , Terapia Nutricional , Revisão por Pares , Prebióticos , Probióticos , Indução de Remissão , Reino Unido
17.
J Med Eng Technol ; 38(1): 1-4, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24144117

RESUMO

This study develops a means of delivering electrical stimuli directly to the pial surface of the spinal cord for treatment of intractable pain. This intradural implant must remain in direct contact with the cord as it moves within the spinal canal. Therefore, magnetic resonance imaging was used to measure the movement of the spinal cord between neutral and flexed-back positions in a series of volunteers (n = 16). Following flexion of the back, the mean change in the pedicle-to-spinal cord dorsal root entry zone distance at the T10-11 level was (8.5 ± 6.0) mm, i.e. a 71% variation in the range of rostral-caudal movement of the spinal cord across all patients. There will be a large spectrum of spinal cord strains associated with this observed range of rostral-caudal motions, thus calling for suitable axial compliance within the electrode bearing portion of the intradural implant.


Assuntos
Terapia por Estimulação Elétrica/métodos , Imageamento por Ressonância Magnética/métodos , Medula Espinal/fisiologia , Adulto , Humanos , Vértebras Lombares/anatomia & histologia , Pessoa de Meia-Idade , Medula Espinal/anatomia & histologia , Adulto Jovem
18.
Science ; 343(6169): 1242777, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24324272

RESUMO

The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. Carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorus were measured directly as key biogenic elements; by inference, phosphorus is assumed to have been available. The environment probably had a minimum duration of hundreds to tens of thousands of years. These results highlight the biological viability of fluvial-lacustrine environments in the post-Noachian history of Mars.


Assuntos
Exobiologia , Meio Ambiente Extraterreno , Marte , Água , Baías , Carbono/análise , Sedimentos Geológicos/análise , Sedimentos Geológicos/classificação , Hidrogênio/análise , Concentração de Íons de Hidrogênio , Ferro/análise , Ferro/química , Nitrogênio/análise , Oxirredução , Oxigênio/análise , Fósforo/análise , Salinidade , Enxofre/análise , Enxofre/química
19.
Int J Obes (Lond) ; 37(3): 350-6, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22508335

RESUMO

BACKGROUND: North American (NA) ginseng (Panax quinquefolius) is a popular natural health product (NHP) that has been demonstrated to regulate immune function, inflammatory processes and response to stress and fatigue. Recent evidence suggests that various extracts of NA ginseng may have different bioactivities because of distinct profiles of ginsenosides and polysaccharides. To date, the bioactive role of ginseng on adipocytes remains relatively unexplored. OBJECTIVE: The goal of this work was to study the extract-specific bioactivity of NA ginseng on differentiated preadipocyte gene expression and adipocytokine secretion. METHODS: In vitro differentiated 3T3-L1 preadipocytes were treated with 25 and 50 µg ml of either crude ethanol (EtOH) or aqueous (AQ) NA ginseng extracts, or polysaccharide and ginsenoside extracts isolated from the AQ extract. Global gene expression was studied with microarrays and the resulting data were analyzed with functional pathway analysis. Adipocytokine secretion was also measured in media. RESULTS: Pathway analysis indicated that the AQ extract, and in particular the polysaccharide extract, triggered a global inflammomodulatory response in differentiated preadipocytes. Specifically, the expression of Il-6 (interleukin 6), Ccl5 (chemokine (C-C motif) ligand 5), Nfκb (nuclear factor-kappaB) and Tnfα (tumor necrosis factor alpha) was increased. These effects were also reflected at the protein level through the increased secretion of IL-6 and CCL5. No effect was seen with the EtOH extract or ginsenoside extract. Using a specific toll-like receptor 4 (TLR4) inhibitor reduced the upregulation of inflammatory gene expression, indicating the relevance of this pathway for the signaling capacity of NA ginseng polysaccharides. CONCLUSION: This work emphasizes the distinct bioactivities of different ginseng extracts on differentiated preadipocyte signaling pathways, and highlights the importance of TLR4 for mediating the inflammomodulatory role of ginseng polysaccharides.


Assuntos
Adipócitos/metabolismo , Etanol/farmacologia , Inflamação/tratamento farmacológico , Interleucina-6/metabolismo , Extratos Vegetais/farmacologia , Saponinas/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Células 3T3-L1/efeitos dos fármacos , Células 3T3-L1/metabolismo , Adipócitos/efeitos dos fármacos , Animais , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Quimiocinas/efeitos dos fármacos , Quimiocinas/metabolismo , Inflamação/imunologia , Inflamação/metabolismo , Camundongos , Subunidade p50 de NF-kappa B/efeitos dos fármacos , Subunidade p50 de NF-kappa B/metabolismo , Polissacarídeos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
20.
Neuroimage ; 66: 36-41, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23110884

RESUMO

The EEG/MEG signal is generated primarily by the summation of the post-synaptic potentials of cortical principal cells. At a microcircuit level, these glutamatergic principal cells are reciprocally connected to GABAergic interneurons and cortical oscillations are thought to be dependent on the balance of excitation and inhibition between these cell types. To investigate the dependence of movement-related cortical oscillations on excitation-inhibition balance, we pharmacologically manipulated the GABA system using tiagabine, which blocks GABA Transporter 1(GAT-1), the GABA uptake transporter and increases endogenous GABA activity. In a blinded, placebo-controlled, crossover design, in 15 healthy participants we administered either 15mg of tiagabine or a placebo. We recorded whole-head magnetoencephalograms, while the participants performed a movement task, prior to, one hour post, three hour post and five hour post tiagabine ingestion. Using time-frequency analysis of beamformer source reconstructions, we quantified the baseline level of beta activity (15-30Hz), the post-movement beta rebound (PMBR), beta event-related desynchronisation (beta-ERD) and movement-related gamma synchronisation (MRGS) (60-90Hz). Our results demonstrated that tiagabine, and hence elevated endogenous GABA levels causes, an elevation of baseline beta power, enhanced beta-ERD and reduced PMBR, but no modulation of MRGS. Comparing our results to recent literature (Hall et al., 2011) we suggest that beta-ERD may be a GABAA receptor mediated process while PMBR may be GABAB receptor mediated.


Assuntos
Ritmo beta/fisiologia , Sincronização Cortical/fisiologia , Córtex Motor/fisiologia , Movimento/fisiologia , Ácido gama-Aminobutírico/metabolismo , Adulto , Ritmo beta/efeitos dos fármacos , Sincronização Cortical/efeitos dos fármacos , Estudos Cross-Over , Feminino , Agonistas GABAérgicos/farmacologia , Humanos , Magnetoencefalografia , Masculino , Córtex Motor/efeitos dos fármacos , Ácidos Nipecóticos/farmacologia , Processamento de Sinais Assistido por Computador , Tiagabina , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA