942 resultados para blood-aqueous barrier


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Using a Theory of Planned Behavior (TPB) framework the current study explored the beliefs of current blood donors (N=172) about donating during a low and high-risk phase of a potential avian influenza outbreak. While the majority of behavioral, normative, and control beliefs identified in preliminary research differed as a function of donors’ intentions to donate during both phases of an avian influenza outbreak, regression analyses suggested that the targeting of different specific beliefs during each phase of an outbreak would yield most benefit in bolstering donors’ intentions to remain donating. The findings provide insight in how to best motivate donors in different phases of an avian influenza outbreak.

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High-performance liquid chromatography coupled with solid phase extraction method was developed for determination of isofraxidin in rat plasma after oral administration of Acanthopanax senticosus extract (ASE), and pharmacokinetic parameters of isofraxidin either in ASE or pure compound were measured. The HPLC analysis was performed on a Dikma Diamonsil RP(18) column (4.6 mm x 150 mm, 5 microm) with the isocratic elution of solvent A (acetonitrile) and solvent B (0.1% aqueous phosphoric acid, v/v) (A : B = 22 : 78) and the detection wavelength was set at 343 nm. The calibration curve was linear over the range of 0.156-15.625 microg/ml. The limit of detection was 60 ng/ml. The intra-day precision was 5.8%, and the inter-day precision was 6.0%. The recovery was 87.30+/-1.73%. When the dosage of ASE is equal to pure compound caculated by the amount of isofraxidin, it has been found to have two maximum concentrations in plasma while the pure compound only showed one peak in the plasma concentration-time curve. The determined content of isofraxidin in plasma after oral administration of ASE is the total contents of free isofraxidin and its precursors in ASE in vitro. The pharmacokinetic characteristics of ASE showed the priority of the extract and the properities of traditional Chinese medicine.

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A method for the rapid and simultaneous determination of 6,7-dimethylesculetin (CAS 120-08-1) and geniposide (CAS 24512-63-8) in rat plasma has been developed, using validated high performance liquid chromatography (HPLC) with solid phase extraction (SPE). The HPLC analysis was performed on a commercially available column (200 mm x 4.6 mm, 5 microm) with acetonitrile-methanol-0.1% aqueous formic acid as mobile phase and the UV detection at 343 nm and 238 nm for 6,7-dimethylesculetin and geniposide, respectively. The calibration curves for 6,7-dimethylesculetin and geniposide were linear over the range 0.4-25.6 microg/mL and 1.12-71.68 microg/mL, respectively. The lower limits of quantitation were 0.40 microg/ mL and 1.12 microg/mL, and the lower limits of detection were 0.06 microg/mL and 0.09 microg/ mL, respectively. The intra-day and inter-day precision for 6,7-dimethylesculetin and geniposide were < 5%, whereas the absolute recovery percentages were > 74%. A successful application of the developed HPLC analysis was demonstrated for the pharmacokinetic study of a Traditional Chinese Medicine formula of Yin Chen Hao Tang preparation.

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This thesis provides an experimental and computational platform for investigating the performance and behaviour of water filled, plastic portable road safety barriers in an isolated impact scenario. A schedule of experimental impact tests were conducted assessing the impact response of an existing design of road safety barrier utilising a novel horizontal impact testing system. A coupled finite element and smooth particle hydrodynamic model of the barrier system was developed and validated against the results of the experimental tests. The validated model was subsequently used to assess the effect of certain composite materials on the impact performance of the water filled, portable road safety barrier system.

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Genomic DNA obtained from patient whole blood samples is a key element for genomic research. Advantages and disadvantages, in terms of time-efficiency, cost-effectiveness and laboratory requirements, of procedures available to isolate nucleic acids need to be considered before choosing any particular method. These characteristics have not been fully evaluated for some laboratory techniques, such as the salting out method for DNA extraction, which has been excluded from comparison in different studies published to date. We compared three different protocols (a traditional salting out method, a modified salting out method and a commercially available kit method) to determine the most cost-effective and time-efficient method to extract DNA. We extracted genomic DNA from whole blood samples obtained from breast cancer patient volunteers and compared the results of the product obtained in terms of quantity (concentration of DNA extracted and DNA obtained per ml of blood used) and quality (260/280 ratio and polymerase chain reaction product amplification) of the obtained yield. On average, all three methods showed no statistically significant differences between the final result, but when we accounted for time and cost derived for each method, they showed very significant differences. The modified salting out method resulted in a seven- and twofold reduction in cost compared to the commercial kit and traditional salting out method, respectively and reduced time from 3 days to 1 hour compared to the traditional salting out method. This highlights a modified salting out method as a suitable choice to be used in laboratories and research centres, particularly when dealing with a large number of samples.

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Migraine is a debilitating neurovascular disorder, with a substantial genetic component. The exact cause of a migraine attack is unknown; however cortical hyperexcitability is thought to play a role. As Gamma-aminobutyric Acid (GABA) is the major inhibitory neurotransmitter in the brain, malfunctioning of this system may be a cause of the hyperexcitability. To date, there has been limited research examining the gene expression or genetics of GABA receptors in relation to migraine. The aim of our study was to determine if GABA receptors play a role in migraine by investigating their gene expression using profile in migraine affected individuals and non-affected controls by Q-PCR. Gene expression of GABA(A) receptor subunit isoforms (GABRA3, GABRB3, GABRQ) and GABA(B) receptor 2 (GABBR2) was quantified in mRNA obtained from peripheral blood leukocytes from 28 migraine subjects and 22 healthy control subjects. Analysis of results showed that two of the tested genes, GABRA3 and GABBR2, were significantly down regulated in migraineurs (P=0.018; P=0.017), compared to controls. Results from the other tested genes did not show significant gene expression variation. The results indicate that there may be specific GABA receptor gene expression variation in migraine, particularly involving the GABRA3 and GABBR2 genes. This study also identifies GABRA3 and GABBR2 as potential biomarkers to select migraineurs that may be more responsive to GABA agonists with future investigations in this area warranted.

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Objective To evaluate relative telomere length of female migraine patients. Background Migraine is a debilitating disorder affecting 6-28% of the population. Studies on the mechanisms of migraine have demonstrated genetic causes but the pathophysiology and subcellular effects of the disease remain poorly understood. Shortened telomere length is associated with age-related or chronic diseases, and induced stresses. Migraine attacks may impart significant stress on cellular function, thus this study investigates a correlation between shortening of telomeres and migraine. Methods Relative telomere length was measured using a previously described quantitative polymerase chain reaction method. A regression analysis was performed to assess differences in mean relative telomere length between migraine patients and healthy controls. Results The leukocyte telomeres of a cohort of 142 Caucasian female migraine subjects aged 18-77 years and 143 matched 17-77-year-old healthy control Caucasian women were examined.A significantly shorter relative telomere length was observed in the migraine group compared with the control group after adjusting for age and body mass index (P = .001). In addition, age of onset was observed to associate with the loss of relative telomere length, especially at early age of onset (<17 years old). No association was observed between relative telomere length and the severity and frequency of migraine attacks and the duration of migraine. Conclusion Telomeres are shorter in migraine patients and there is more variation in telomere length in migraine patients.

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Family linkage studies were used to detect two linkage relationships on human chromosome 1. The B subunit of coagulation factor XIII showed significant linkage to renin with a maximum lod score of 5.071 at a distance of 10 cM. Significant linkage was also shown between the Duffy blood group and α-spectrin with linkage results giving a combined lod score of 3.194 at 5 cM.

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Injured bone initiates the healing process by forming a blood clot at the damaged site. However, in severe damage, synthetic bone implants are used to provide structural integrity and restore the healing process. The implant unavoidably comes into direct contact with whole blood, leading to a blood clot formation on its surface. Despite this, most research in bone tissue engineering virtually ignores the important role of a blood clot in supporting healing. Surface chemistry of a biomaterial is a crucial property in mediating blood-biomaterials interactions, and hence the formation of the resultant blood clot. Surfaces presenting mixtures of functional groups carboxyl (–COOH) and methyl (–CH3) have been shown to enhance platelet response and coagulation activation, leading to the formation of fibrin fibres. In addition, it has been shown that varying the compositions of these functional groups and the length of alkyl groups further modulate the immune complement response. In this study, we hypothesised that a biomaterial surface with mixture of –COOH/–CH3(methyl), –CH2CH3 (ethyl) or –(CH2)3CH3 (butyl) groups at different ratios would modulate blood coagulation and complement activation, and eventually tailor the structural and functional properties of the blood clot formed on the surface, which subsequently impacts new bone formation. Firstly, we synthesised a series of materials composed of acrylic acid (AA), and methyl (MMA), ethyl (EMA) or butyl methacrylates (BMA) at different ratios and coated on the inner surfaces of incubation vials. Our surface analysis showed that the amount of –COOH groups on the surface coatings was lower than the ratios of AA prepared in the materials even though the surface content of –COOH groups increased with increasing in AA ratios. It was indicated that the surface hydrophobicity increased with increasing alkyl chain length: –CH 3 > –CH2CH3 > –(CH2)3CH3, and decreased with increasing –COOH groups. No significant differences in surface hydrophobicity was found on surfaces with –CH3 and –CH2CH3 groups in the presence of –COOH groups. The material coating was as smooth as uncoated glass and without any major flaws. The average roughness of material-coated surface (3.99 ± 0.54 nm) was slightly higher than that of uncoated glass surface (2.22 ± 0.29 nm). However, no significant differences in surface average roughness was found among surfaces with the same functionalities at different –COOH ratios nor among surfaces with different alkyl groups but the same –COOH ratios. These suggested that the surface functional groups and their compositions had a combined effect on modulating surface hydrophobicity but not surface roughness. The second part of our study was to investigate the effect of surface functional groups and their compositions on blood cascade activation and structural properties of the formed clots. It was found that surfaces with –COOH/–(CH2)3CH3 induced a faster coagulation activation than those with –COOH/–CH3 and –CH2CH3, regardless of the –COOH ratios. An increase in –COOH ratios on –COOH/–CH3 and –CH2CH3 surfaces decreased the rate of activation. Moreover, all material-coated surfaces markedly reduced the complement activation compared to uncoated glass surfaces, and the pattern of complement activation was entirely similar to that of surface-induced coagulation, suggesting there is an interaction between two cascades. The clots formed on material-coated surfaces had thicker fibrin with a tighter network at the exterior when compared to uncoated glass surfaces. Compared to the clot exteriors, thicker fibrins with a loose network were found in clot interiors. Coated surfaces resulted in more rigid clots with a significantly slower fibrinolysis after 1 h of lysis when compared to uncoated glass surfaces. Significant differences in fibrinolysis after 1 h of lysis among clots on material-coated surfaces correlated well with the differences in fibrin thickness and density at clot exterior. In addition, more growth factors were released during clot formation than during clot lysis. From an intact clot, there was a correlation between the amount of PDGF-AB release and fibrin density. Highest amount of PDGF-AB was released from clots formed on surfaces with 40% –COOH/60% –CH 3 (i.e. 65MMA). During clot lysis, the release of PDGF-AB also correlated with the fibrinolytic rate while the release of TGF-â1 was influenced by the fibrin thickness. This suggested that different clot structures led to different release profiles of growth factors in clot intact and degrading stages. We further validated whether the clots formed on material-coatings provide the microenvironment for improved bone healing by using a rabbit femoral defect model. In this pilot study, the implantation of clots formed on 65MMA coatings significantly increased new bone formation with enhanced chondrogenesis, osteoblasts activity and vascularisation, but decreased inflammatory macrophage number at the defects after 4 weeks when compared to commercial bone grafts ChronOSTM â-TCP granules. Empty defects were observed when blood clot formation was inhibited. In summary, our study demonstrated that surface functional groups and their relative ratios on material coatings synergistically modulate activation of blood cascades, resultant fibrin architecture, rigidity, susceptibility to fibrinolysis as well as growth factor release of the formed clots, which ultimately alter the healing microenvironment of injured bones.

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Background Several lines of evidence suggests that transcription factors are involved in the pathogenesis of Multiple Sclerosis (MS) but a complete mapping the whole network has been elusive. One of the reasons is that there are several clinical subtypes of MS and transcription factors which may be involved in one subtype may not be in others. We investigated the possibility that this network could be mapped using microarray technologies and modern bioinformatics methods on a dataset from whole blood in 99 untreated MS patients (36 Relapse Remitting MS, 43 Primary Progressive MS, and 20 Secondary Progressive MS) and 45 age-matched healthy controls, Methodology/Principal Findings We have used two different analytical methodologies: a differential expression analysis and a differential co-expression analysis, which have converged on a significant number of regulatory motifs that seem to be statistically overrepresented in genes which are either differentially expressed (or differentially co-expressed) in cases and controls (e.g. V$KROX_Q6, p-value < 3.31E-6; V$CREBP1_Q2, p-value < 9.93E-6, V$YY1_02, p-value < 1.65E-5). Conclusions/significance: Our analysis uncovered a network of transcription factors that potentially dysregulate several genes in MS or one or more of its disease subtypes. Analysing the published literature we have found that these transcription factors are involved in the early T-lymphocyte specification and commitment as well as in oligodendrocytes dedifferentiation and development. The most significant transcription factors motifs were for the Early Growth response EGR/KROX family, ATF2, YY1 (Yin and Yang 1), E2F-1/DP-1 and E2F-4/DP-2 heterodimers, SOX5, and CREB and ATF families.

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Purpose/Objective: The basis for poor outcomes in some patients post transfusion remains largely unknown. Despite leukodepletion, there is still evidence of immunomodulatory effects of transfusion that require further study. In addition, there is evidence that the age of blood components transfused significantly affects patient outcomes. Myeloid dendritic cell (DC) and monocyte immune function were studied utilising an in vitro whole blood model of transfusion. Materials and methods: Freshly collected (‘recipient’) whole blood was cultured with ABO compatible leukodepleted PRBC at 25% blood replacement-volume (6hrs). PRBC were assayed at [Day (D) 2, 14, 28and 42 (date-of expiry)]. In parallel, LPS or Zymosan (Zy) were added to mimic infection. Recipients were maintained for the duration of the time course (2 recipients, 4 PRBC units, n = 8).Recipient DC and monocyte intracellular cytokines and chemokines (IL-6, IL-10, IL-12,TNF-a, IL-1a, IL-8, IP-10, MIP-1a, MIP-1b, MCP-1) were measured using flow cytometry. Changes in immune response were calculated by comparison to a parallel no transfusion control (Wilcoxin matched pairs). Influence of storage age was calculated using ANOVA. Results: Significant suppression of DC and monocyte inflammatory responses were evident. DC and monocyte production of IL-1a was reduced following exposure to PRBC regardless of storage age (P < 0.05 at all time points). Storage independent PRBC mediated suppression of DC and monocyte IL-1a was also evident in cultures costimulated with Zy. In cultures co-stimulated with either LPS or Zy, significant suppression of DC and monocyte TNF-a and IL-6 was also evident. PRBC storage attenuated monocyte TNF-a production when co-cultured with LPS (P < 0.01 ANOVA). DC and monocyte production of MIP-1a was significantly reduced following exposure to PRBC (DC: P < 0.05 at D2, 28, 42; Monocyte P < 0.05 all time points). In cultures co-stimulated with LPS and zymosan, a similar suppression of MIP-1a production was also evident, and production of both DC and monocyte MIP-1b and IP-10 were also significantly reduced. Conclusions: The complexity of the transfusion context was reflected in the whole blood approach utilised. Significant suppression of these key DC and monocyte immune responses may contribute to patient outcomes, such as increased risk of infection and longer hospital stay, following blood transfusion.

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Introduction: Dengue poses a problem for safe transfusion of blood components with confirmed reports of transfusion-transmission in Hong Kong and Singapore. The largest outbreak in 50 years occurred in North Queensland during 2008/2009 with more than 1,000 confirmed cases in Cairns and Townsville. During this outbreak, supplementary questioning for all donors was implemented, and fresh components were not manufactured from at risk donors. We aim to determine the seroprevalence of dengue exposure in this population during this epidemic. Methods: Samples were collected from blood donors during the 2008/2009 epidemic and 3 months after the last confirmed case. These samples were tested for anti-Dengue IgM, IgG and NS1 antigen with commercially available ELISA based assay kits from PanBio. Results: Initial analyses revealed 2.7% of samples from deferred donors were IgM repeat reactive. Of these, 16% were also positive for anti-dengue IgG, while none of these were positive for the NS1 viral antigen. However, two NS1 positives were found in samples collected from deferred donors. Conclusions: This initial analysis represents recent and cumulative past exposure in a presumed asymptomatic population, and will provide documentation of the rate of asymptomatic dengue infection during the epidemic. This data can also be used to assess the risk of dengue becoming endemic in North Queensland given that the mosquito vector is established in this region.

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This study investigated how and to what degree “hybrid photography”—the simultaneous use of indexical and fictional properties and strategies— innovates the representation of animals within animalcentric, ecocentric frameworks. Design theory structured this project’s Practice-led, Visual research methodology framework. Grounded theory processes articulated emerging categories of hybrid photography through systematically and comparatively treating animal photography works for reflexive analysis. Design theory then applied and clarified categories, developing practice that re-visualised shark perspectives as new ecological discourse. Shadows, a creative practice installation, realised a full-scale photographic investigation into shark and marine animal realities of a specific environment—Heron Island and Gladstone, Great Barrier Reef—facing ecological crisis from dredging and development at Gladstone Harbour. Works rendered and explored hybrid photography’s capacity for illuminating nonhuman animals, in particular, sharks, and comprise 65% of this project’s weighting. This exegetical paper offers a definition, strategies and evaluation of hybrid photography in unsettling animal perspectives as effective ecological discourse, and comprises 35%.

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Portable water-filled barriers (PWFB) are roadside structures used to separate moving traffic from work-zones. Numerical PWFB modelling is preferred in the design stages prior to actual testing. This paper aims to study the fluid-structure interaction of PWFB under vehicular impact using several methods. The strategy to treat water as non-structural mass was proposed and the errors were investigated. It was found that water can be treated with the FEA-NSM model for velocities higher than 80kmh-1. However, full SPH/FEA model is still the best treatment for water and necessary for lower impact velocities. The findings in this paper can be used as guidelines for modelling and designing PWFB.

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Purpose: Hyperactive platelets contribute to the thrombotic response in humans, and exercise transiently increases platelet function. Caffeine is routinely used by athletes as an ergogenic aid, but the combined effect of exercise and caffeine on platelet function has not been investigated. Methods: Twelve healthy males were randomly assigned to one of four groups and undertook four experimental trials of a high-intensity aerobic interval training (AIT) bout or rest with ingestion of caffeine (3 mg·kg-1) or placebo. AIT was 8 × 5 min at approximately 75% peak power output (approximately 80% V?O2peak) and 1-min recovery (approximately 40% peak power output, approximately 50% V?O2peak) intervals. Blood/urine was collected before, 60, and 90 min after capsule ingestion and analyzed for platelet aggregation/activation. Results: AIT increased platelet reactivity to adenosine diphosphate (placebo 30.3%, caffeine 13.4%, P < 0.05) and collagen (placebo 10.8%, caffeine 5.1%, P < 0.05) compared with rest. Exercise placebo increased adenosine diphosphate-induced aggregation 90 min postingestion compared with baseline (40.5%, P < 0.05), but the increase when exercise was combined with caffeine was small (6.6%). During the resting caffeine protocol, collagen-induced aggregation was reduced (-4.3%, P < 0.05). AIT increased expression of platelet activation marker PAC-1 with exercise placebo (P < 0.05) but not when combined with caffeine. Conclusion: A single bout of AIT increases platelet function, but caffeine ingestion (3 mg·kg) does not exacerbate platelet function at rest or in response to AIT. Our results provide new information showing caffeine at a dose that can elicit ergogenic effects on performance has no detrimental effect on platelet function and may have the potential to attenuate increases in platelet activation and aggregation when undertaking strenuous exercise.