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Andrew Harris

Publications and source records attributed to Andrew Harris.

6 recordsLinked to original sources
PubMed2006

Novel methods of quantitative real-time PCR data analysis in a murine Helicobacter pylori vaccine model.

Monitoring of Helicobacter pylori in the stomach is important to assess the efficacy of new vaccines against the pathogen. To realise the full potential of quantitative real-time PCR (q-PCR), this technology has to offer accurate and easy models of post-PCR data analysis. In this work, we used a variety of absolute and relative approaches of q-PCR data analysis to monitor the H. pylori infection in the stomach of immunized mice. Relative quantification was performed with Ct-based methods, with the DART program, and with two methods based on the mathematical analysis of raw fluorescence kinetics, the LinReg program and the Sigmoidal Curve Fitting Method. The different calculation methods were validated in mice immunized with cell lysates of Lactococcus lactis expressing the H. pylori urease subunit B in combination with cholera toxin. The H. pylori load was found to be reduced in immunized mice by a factor of 50-144, depending on the calculation method employed. We found that relative quantification using DART, LinReg and Sigmoidal Curve Fitting methods generated similar results (infection ratios of 54-58) with absolute quantification results (54-65). Results were very different to those using relative quantification Ct-based methods without a correction for PCR efficiency (ratio of 92-144) and with results based on conventional culture method (ratio of 34). Overall, this study demonstrates that q-PCR associated with a relative quantification analysis is a powerful tool for the monitoring of microorganisms in tissue. It could be used as an alternative to standard curve approach especially for the investigation of microbial load in vaccine models.

Animals↗
PubMed2006

Tax-exempt private placements: a new opportunity for not-for-profit providers.

Tax-exempt private placements offer an attractive financing alternative for not-for-profit healthcare providers for which the public debt market is no longer a viable option. They offer the following advantages: Greater flexibility Lower fees. Less paperwork. Fewer players. Shorter time to complete.

Capital Financing↗
PubMed2005

Evaluation of DNA extraction methods from mouse stomachs for the quantification of H. pylori by real-time PCR.

Real-time PCR methods have recently been developed for the quantification of Helicobacter pylori from infected mouse stomachs. However, the extent to which results is affected by the efficiency of different methods of DNA extraction and the degree of inhibition of the subsequent PCR have largely been ignored. In this study, mouse stomachs were processed using two homogenisation methods: complete disruption using a blender and homogenisation by vortexing with glass beads. Each procedure was followed by DNA purification by three different protocols-two commercially available kits-Qiagen DNA Mini Tissue kit and Qiagen Stool Kit and a phenol-chloroform extraction method. PCR inhibition was assessed by screening for mouse DNA and for H. pylori DNA after spiking stomach extracts with H. pylori 16S rDNA. PCR inhibition was found to be lower in DNA samples prepared by vortexing and processed by column kits. Validation of procedures was performed by quantification of H. pylori DNA and mouse DNA in infected mouse stomachs. Homogenisation with glass beads followed by the Qiagen Tissue kit was found to be the most suitable protocol combining high extraction and detection efficiency of 16S rDNA in the presence of a mouse DNA background.

Animals↗
PubMed2005

Intestinal innate immunity to Campylobacter jejuni results in induction of bactericidal human beta-defensins 2 and 3.

Campylobacter jejuni is the most prevalent cause of bacterial diarrhea worldwide. Despite the serious health problems caused by this bacterium, human innate immune responses to C. jejuni infection remain poorly defined. Human beta-defensins, a family of epithelial antimicrobial peptides, are a major component of host innate defense at the gastrointestinal mucosal surface. In this study, the effect of two different C. jejuni wild-type strains on human intestinal epithelial innate responses was investigated. Up-regulation of beta-defensin gene and peptide expression during infection was observed and recombinant beta-defensins were shown to have a direct bactericidal effect against C. jejuni through disruption of cell wall integrity. Further studies using an isogenic capsule-deficient mutant showed that, surprisingly, the absence of the bacterial polysaccharide capsule did not change the innate immune responses induced by C. jejuni or the ability of C. jejuni to survive exposure to recombinant beta-defensins. This study suggests a major role for this family of antimicrobial peptides in the innate immune defense against this human pathogen.

Bacterial Capsules↗
PubMed2002

Applying community-oriented primary care methods in British general practice: a case study.

BACKGROUND: The '75 and over' assessments built into the 1990 contract for general practice have failed to enthuse primary care teams or make a significant impact on the health of older people. Alternative methods for improving the health of older people living at home are being sought. AIM: To test the feasibility of applying community-oriented primary care methodology to a relatively deprived sub-population of older people in a relatively deprived area. DESIGN OF STUDY: A combination of developmental and triangulation approaches to data analysis. SETTING: Four general practices in an inner London borough. METHOD: A community-oriented primary care approach was used to initiate innovative care for older people, supported financially by the health authority and practically by primary care academics. RESULTS: All four practices identified problems needing attention in the older population, developed different projects focused on particular needs among older people, and tested them in practice. Patient and public involvement were central to the design and implementation processes in only one practice. Innovations were sustained in only one practice, but some were adopted by a primary care group and others extended to a wider group of practices by the health authority. CONCLUSION: A modified community-oriented primary care approach can be used in British general practice, and changes can be promoted that are perceived as valuable by planning bodies. However, this methodology may have more impact at primary care trust level than at practice level.

Aged↗