859 research outputs found

    Improving the palatability of colonoscopy preparations

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    Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. The most reliable screening method of CRC is a colonoscopy which requires a 4-Liter polymer with electrolytes preparation. Two in five patients are non-compliant to their colonoscopy schedules, with many patients who abstain reporting refusal due to significant discomfort associated with this preparation. Furthermore, there are distinct gender differences in the tolerance of colonoscopy preparations in male and female populations. We hypothesize the differences in clinic are a result of toxic effects of the drug associated with poor mixing by individual patients. PEG, the drug, is approved by the FDA for use in medical devices and has been recognized for many years as a biocompatible polymer but few studies have truly studied the short-term and long-term effects of high concentrations of PEG. We studied the toxic effects of the common preparations over a time frame of 2 hours, 12 hours, 24 hours, and 48 hours and found that at higher concentrations of the drug, more cells were killed. We have developed an oral capsule that dissolves in stomach acid to control the release of PEG – accurately controlling the amount of drug that is ingested by patients and reducing adverse effects associated with the taste colonoscopy preparations. We have looked at and evaluated the capsules for chemical content and tested them with cells to confirm their safety

    Mitigating Intersection Attacks in Anonymous Microblogging

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    Anonymous microblogging systems are known to be vulnerable to intersection attacks due to network churn. An adversary that monitors all communications can leverage the churn to learn who is publishing what with increasing confidence over time. In this paper, we propose a protocol for mitigating intersection attacks in anonymous microblogging systems by grouping users into anonymity sets based on similarities in their publishing behavior. The protocol provides a configurable communication schedule for users in each set to manage the inevitable trade-off between latency and bandwidth overhead. In our evaluation, we use real-world datasets from two popular microblogging platforms, Twitter and Reddit, to simulate user publishing behavior. The results demonstrate that the protocol can protect users against intersection attacks at low bandwidth overhead when the users adhere to communication schedules. In addition, the protocol can sustain a slow degradation in the size of the anonymity set over time under various churn rates

    Validation and implementation of array comparative genomic hybridisation as a first line test in place of postnatal karyotyping for genome imbalance

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    <p>Abstract</p> <p>Background</p> <p>Several studies have demonstrated that array comparative genomic hybridisation (CGH) for genome-wide imbalance provides a substantial increase in diagnostic yield for patients traditionally referred for karyotyping by G-banded chromosome analysis. The purpose of this study was to demonstrate the feasibility of and strategies for, the use of array CGH in place of karyotyping for genome imbalance, and to report on the results of the implementation of this approach.</p> <p>Results</p> <p>Following a validation period, an oligoarray platform was chosen. In order to minimise costs and increase efficiency, a patient/patient hybridisation strategy was used, and analysis criteria were set to optimise detection of pathogenic imbalance. A customised database application with direct links to a number of online resources was developed to allow efficient management and tracking of patient samples and facilitate interpretation of results. Following introduction into our routine diagnostic service for patients with suspected genome imbalance, array CGH as a follow-on test for patients with normal karyotypes (n = 1245) and as a first-line test (n = 1169) gave imbalance detection rates of 26% and 22% respectively (excluding common, benign variants). At least 89% of the abnormalities detected by first line testing would not have been detected by standard karyotype analysis. The average reporting time for first-line tests was 25 days from receipt of sample.</p> <p>Conclusions</p> <p>Array CGH can be used in a diagnostic service setting in place of G-banded chromosome analysis, providing a more comprehensive and objective test for patients with suspected genome imbalance. The increase in consumable costs can be minimised by employing appropriate hybridisation strategies; the use of robotics and a customised database application to process multiple samples reduces staffing costs and streamlines analysis, interpretation and reporting of results. Array CGH provides a substantially higher diagnostic yield than G-banded chromosome analysis, thereby alleviating the burden of further clinical investigations.</p

    Impacts of community resilience on the implementation of a mental health promotion program in rural Australia

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    Mental health promotion programs are important in rural communities but the factors which influence program effectiveness remain unclear. The aim of this mixed-methods study was to assess how community resilience affected the implementation of a mental health promotion program in rural Tasmania, Australia. Four study communities were selected based on population size, rurality, access to local support services, history of suicide within the community, and maturity of the mental health promotion program. Data from self-report questionnaires (n = 245), including items of Communities Advancing Resilience Toolkit (CART) assessment, and qualitative (focus group and interview) data from key local stakeholders (n = 24), were pooled to explore the factors perceived to be influencing program implementation. Survey results indicate the primary community resilience strengths across the four sites were related to the ‘Connection and Caring’ domain. The primary community resilience challenges related to resources. Qualitative findings suggested lack of communication and leadership are key barriers to effective program delivery and identified a need to provide ongoing support for program staff. Assessment of perceived community resilience may be helpful in informing the implementation of mental health promotion programs in rural areas and, in turn, improve the likelihood of their success and sustainability

    The role of C-terminal amidation in the membrane interactions of the anionic antimicrobial peptide, maximin H5

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    Maximin H5 is an anionic antimicrobial peptide from amphibians, which carries a C-terminal amide moiety, and was found to be moderately haemolytic (20%). The α-helicity of the peptide was 42% in the presence of lipid mimics of erythrocyte membranes and was found able to penetrate (10.8mNm(-1)) and lyse these model membranes (64 %). In contrast, the deaminated peptide exhibited lower levels of haemolysis (12%) and α-helicity (16%) along with a reduced ability to penetrate (7.8mNm(-1)) and lyse (55%) lipid mimics of erythrocyte membranes. Taken with molecular dynamic simulations and theoretical analysis, these data suggest that native maximin H5 primarily exerts its haemolytic action via the formation of an oblique orientated α-helical structure and tilted membrane insertion. However, the C-terminal deamination of maximin H5 induces a loss of tilted α-helical structure, which abolishes the ability of the peptide's N-terminal and C-terminal regions to H-bond and leads to a loss in haemolytic ability. Taken in combination, these observations strongly suggest that the C-terminal amide moiety carried by maximin H5 is required to stabilise the adoption of membrane interactive tilted structure by the peptide. Consistent with previous reports, these data show that the efficacy of interaction and specificity of maximin H5 for membranes can be attenuated by sequence modification and may assist in the development of variants of the peptide with the potential to serve as anti-infective

    Late-acting dominant lethal genetic systems and mosquito control

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    BACKGROUND: Reduction or elimination of vector populations will tend to reduce or eliminate transmission of vector-borne diseases. One potential method for environmentally-friendly, species-specific population control is the Sterile Insect Technique (SIT). SIT has not been widely used against insect disease vectors such as mosquitoes, in part because of various practical difficulties in rearing, sterilization and distribution. Additionally, vector populations with strong density-dependent effects will tend to be resistant to SIT-based control as the population-reducing effect of induced sterility will tend to be offset by reduced density-dependent mortality. RESULTS: We investigated by mathematical modeling the effect of manipulating the stage of development at which death occurs (lethal phase) in an SIT program against a density-dependence-limited insect population. We found late-acting lethality to be considerably more effective than early-acting lethality. No such strains of a vector insect have been described, so as a proof-of-principle we constructed a strain of the principal vector of the dengue and yellow fever viruses, Aedes (Stegomyia) aegypti, with the necessary properties of dominant, repressible, highly penetrant, late-acting lethality. CONCLUSION: Conventional SIT induces early-acting (embryonic) lethality, but genetic methods potentially allow the lethal phase to be tailored to the program. For insects with strong density-dependence, we show that lethality after the density-dependent phase would be a considerable improvement over conventional methods. For density-dependent parameters estimated from field data for Aedes aegypti, the critical release ratio for population elimination is modeled to be 27% to 540% greater for early-acting rather than late-acting lethality. Our success in developing a mosquito strain with the key features that the modeling indicated were desirable demonstrates the feasibility of this approach for improved SIT for disease control

    The Development of FVIII Inhibitor in Hispanic American Patients with Hemophilia A Critically Impacts Coagulation Potential

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    Background: Hemophilia A (HA) is caused by deficiencies in plasma-FVIII and heterogeneous factor-VIII-gene mutations that impair intrinsic coagulation amplification. In severe hemophilia A patients (HAPs), FVIII infusions are begun at toddlerhood to prevent hemarthrosis induced crippling. However, approximately 30% of these patients develop FVIII inhibitors. Gain-of-function mutations in the common pathway of coagulation increases coagulation potential and decreases bleeding and FVIII-utilization in HAPs which should decrease FVIII-inhibitor-risk. We identified loss-of-function mutations in this pathway which decrease coagulation-potential as they increase FVIII-inhibitor risk in HAPs. Methods: We screened Mexican-American-pedigrees of the South-Texas-Family-Study (STFS) for protein-altering-variants. Subjects were genotyped using Illumina-exome-24-chip. Protein-altering-variants were analyzed for associations with FII:C, PT, and aPTT. Linear-mixed-model-analyses was performed to estimate trait-heritability and examine single-nucleotide-variations (SNVs) for gene association. Significant associations’ p-values fell below Bonferroni-adjusted significance level. Results: Heritability-estimates for FII:C, aPTT, and PT were highly-significant with p-values of 0.49, 0.49, and 0.54 (for all, pT in the FII-gene (F2)—which encodes 543R\u3eL and has a large effect-size on each trait (for all, pT have lower FII:C levels but correspondingly prolonged aPTT and PT times. Conclusion: We hypothesize that FII-543R\u3eL (Prothrombin-RGV) likely contributes to the high-incidence of FVIII-inhibitor-development in HA-patients of Mexican-ancestry, resulting in higher risk of developing anti-tFVIII-antibodies than patients without the variant. Patients with the RGV variant are likely to bleed more which can require surgery, further increasing the development of FVIII inhibitor development
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