Characterization of Mycobacterium avium subsp. hominissuis Interactions with Host Macrophages and Multinucleated Giant Cells

To examine the macrophage response to M. avium, I compared inflammasome and cytosolic sensor expression and activation. My result demonstrated that virulent strains of M. avium (A5 and 104) suppress IL-1β production and induce IFN-β production in macrophages. M. avium mutants deficient at DNA export in the biofilm exhibited reduced intracellular survival and significantly higher IL-1β production than wildtype. IFN-β production appeared to be related to DNA export capability. To further characterize MGCs, we developed a novel in vitro model which is comprised of a human-derived cell line (THP-1) and cytokine stimulation (IFN-γ and TNF-α). Examination of MGCs with transmission electron microscopy uncovered increased lipid droplets and elevated autophagy. My results showed that M. avium survived and replicated in MGCs and that host lipids play a role in intracellular replication. MGC-passaged bacteria were readily phagocytosed and exhibited normal intracellular replication. The mechanism of cell exit is still unclear. The data presented in this dissertation significantly advance our understanding of the macrophage response to M. avium, and the features of MGCs, and how they interact with M. avium. Understanding these host-pathogen interactions has implications for NTM treatment. The idea that eDNA influences intracellular survival and anti-inflammatory signaling needs further study. However, DNA export genes could be a useful target for future therapies

Are there patients missing from community heart failure registers? An audit of clinical practice

BackgroundGeneral practitioners in the UK are financially incentivised, via the Quality Outcomes Framework, to maintain a record of all patients at their practice with heart failure and manage them appropriately. The prevalence of heart failure recorded in primary care registers (0.7–1.0%) is less than reported in epidemiological studies (3–5%). Using an audit of clinical practice, we set out to investigate if there are patients ‘missing’ from primary care heart failure registers and what the underlying mechanisms might be.DesignThe design of this study was as an audit of clinical practice at a UK general practice (n = 9390).MethodsAudit software (ENHANCE-HF) was used to identify patients who may have heart failure via a series of hierarchical searches of electronic records. Heart failure was then confirmed or excluded based on the electronic records by a heart failure specialist nurse and patients added to the register. Outcome data for patients without heart failure was collected after two years.ResultsHeart failure prevalence was 0.63% at baseline and 1.12% after the audit. Inaccurate coding accounted for the majority of missing patients. Amongst patients without heart failure who were taking a loop diuretic, the rate of incident heart failure was 13% and the rate of death or hospitalization with heart failure was 25% respectively during two-year follow-up.ConclusionThere are many patients missing from community heart failure registers which may detriment patient outcome and practice income. Patients without heart failure who take loop diuretics are at high risk of heart failure-related events

Evaluation of the Parasight Platform for Malaria Diagnosis

The World Health Organization estimates that nearly 500 million malaria tests are performed annually. While microscopy and rapid diagnostic tests (RDTs) are the main diagnostic approaches, no single method is inexpensive, rapid, and highly accurate. Two recent studies from our group have demonstrated a prototype computer vision platform that meets those needs. Here we present the results from two clinical studies on the commercially available version of this technology, the Sight Diagnostics Parasight platform, which provides malaria diagnosis, species identification, and parasite quantification. We conducted a multisite trial in Chennai, India (Apollo Hospital [n = 205]), and Nairobi, Kenya (Aga Khan University Hospital [n = 263]), in which we compared the device to microscopy, RDTs, and PCR. For identification of malaria, the device performed similarly well in both contexts (sensitivity of 99% and specificity of 100% at the Indian site and sensitivity of 99.3% and specificity of 98.9% at the Kenyan site, compared to PCR). For species identification, the device correctly identified 100% of samples with Plasmodium vivax and 100% of samples with Plasmodium falciparum in India and 100% of samples with P. vivax and 96.1% of samples with P. falciparum in Kenya, compared to PCR. Lastly, comparisons of the device parasite counts with those of trained microscopists produced average Pearson correlation coefficients of 0.84 at the Indian site and 0.85 at the Kenyan site

Cell-specific microarray profiling experiments reveal a comprehensive picture of gene expression in the C. elegans nervous system

A novel strategy for profiling Caenorhabditis elegans cells identifies transcripts highly enriched in either the embryonic or larval C. elegans nervous system, including 19 conserved transcripts of unknown function that are also expressed in the mammalian brain

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

FINANCIAL FORECASTING USING DECISION TREE (REPTree & C4.5) AND NEURAL NETWORKS (K*) FOR HANDLING THE MISSING VALUES

Missing values are a widespread problem in data analysis. The purpose of this paper is to design a model to handle the missing values in predicting financial health of companies. Forecasting business failure is an important and challenge task for both academic researchers and business practitioners. In this study, we compare the classification of accuracy in decision tree methods (REP tree, C4.5) and with ANN method (K*) to handle the missing values

Mycobacterium avium Infection of Multinucleated Giant Cells Reveals Association of Bacterial Survival to Autophagy and Cholesterol Utilization

Mycobacterium avium subsp. hominissuis (M. avium) is an opportunistic environmental pathogen that typically infects patients with existing lung conditions such as cystic fibrosis or COPD. Pulmonary M. avium infection generates peribronchial granulomas that contain infected macrophages and multinucleated giant cells (MGCs). While granuloma formation with MGCs is a common feature of mycobacterial infection, the role of MGCs within the granulomas as well as in the host-pathogen interaction is poorly understood. To shed light on the role of MGCs, we established a novel in vitro model utilizing THP-1 cells stimulated with a combination of IFN-γ and TNF-α. In this study, we show that MGCs can take up M. avium, which replicates intracellularly before leaving the cell. Bacteria that escape the MGC exhibit a highly invasive phenotype, which warrants further evaluation. Characterization of MGCs with transmission electron microscopy revealed an accumulation of cytoplasmic lipid droplets, autophagic activity, and multiple nuclei. Autophagy markers are upregulated in both uninfected and infected MGCs early in infection, measured by RT-qPCR analysis of Beclin-1 and LC3. Inhibition of autophagy with siRNA significantly reduced M. avium survival significantly in THP-1 macrophages. Depletion of host cholesterol and sphingomyelin in MGCs also resulted in decreased survival of M. avium. These processes potentially contribute to the formation of a supportive intracellular environment for the pathogen. Collectively, our results suggest that M. avium is adapted to replicate in MGCs and utilize them as a springboard for local spread

St. John's Daily Star, 1920-08-18

The St. John's Daily Star was published daily except Sunday between 17 April 1915 - 23 July 1921