Browsing by Subject "Gastroenterology"

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    Open Access
    Phenotypic analysis of peripheral B cell populations during Mycobacterium tuberculosis infection and disease
    (2016) du Plessis, Willem J; Keyser, Alana; Walzl, Gerhard; Loxton, André G
    Abstract Background Mycobacterium tuberculosis (Mtb) remains an unresolved threat resulting in great annual loss of life. The role of B cells during the protective immunity to Mtb is still unclear. B cells have been described as effector cells in addition to their role as antibody producing cells during disease. Here we aim to identify and characterize the frequency of peripheral B-cell subpopulations during active Tuberculosis and over treatment response. Analysis were done for both class switched (CS) and non-class switched (NCS) phenotypes. Methods We recruited participants with active untreated pulmonary Tuberculosis, other lung diseases and healthy community controls. All groups were followed up for one week from recruitment and the TB cases till the end of treatment (month 6). Results Peripheral blood samples were collected, stained with monoclonal antibodies to CD19 + cells, Immunoglobulin (Ig) M, plasma cells (CD 138 + ), marker of memory (CD27 + ), immune activation (CD23 + ) and acquired on a flow cytometer. Circulating Marginal zone B cells (CD19 + IgM + CD23 − CD27 + ) and memory phenotypes are able to distinguish between TB diagnosis and end of treatment. The frequency of mature B cells from TB cases are lower than that of other-lung diseases at diagnosis. A subpopulation of activated memory B cells (CD19 + IgM + CD23 + CD27 + ) cells are present at the end of TB treatment. Conclusions This study identified distinctive B cell subpopulations present during active TB disease and other lung disease conditions. These cell populations warrants further examination in larger studies as it may be informative as cell markers or as effectors/regulators in TB disease or TB treatment response.
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    Open Access
    Predictors of emergency colectomy in patients admitted to Groote Schuur Hospital with acute severe ulcerative colitis between1st January 2003 and 1st January 2013
    (2016) Mokhele, Nnete Nimrod; Watermeyer, Gillian
    INTRODUCTION: Acute Severe Ulcerative Colitis (ASUC) is a life threatening condition which requires urgent and aggressive medical therapy to reduce mortality, morbidity and avoid surgery; the mainstay of treatment is intravenous corticosteroids. To facilitate this process it is essential to identify patients at high risk of poor outcomes and emergency colectomy. Numerous risk factors predicting the need for surgery have described in the Western literature both at presentation and on day 3 of intravenous therapy, however there are no local data addressing this issue. As such it is unclear if these predictors are applicable in our setting. The aim of this study is thus to identify risk factors for emergency colectomy in patients admitted to Groote Schuur Hospital with ASUC. METHODS: A retrospective cohort study of 98 patients admitted with ASUC between January 2003 and January 2013 was performed. Clinical, demographic, laboratory, radiological and endoscopic factors on admission and 3 days thereafter were analysed as predictors of colectomy by univariate and multivariate analysis. Patients were followed up retrospectively for 90 days RESULTS: Twenty five percent of the cohort underwent emergency colectomy, 80% within 15 days of presentation. On univariate analysis factors on admission which predicted colectomy were exposure to oral corticosteroids (p=0.01), megacolon (p=0.049) or mucosal islands (p=0.04) on abdominal Xray, and a short duration from UC diagnosis until presentation with ASUC (p=0.04). There was no significant association between ethnicity, age at UC diagnosis, gender, family history of IBD, or smoking status. There was also no association with baseline haemoglobin or CRP. The only day 3 variable that significantly predicted colectomy was serum albumin (p=0.01).This was also the only variable to remain significant on multivariate analysis (OR 0.79, 95% CI 0.65-0.97, p=0.01). CONCLUSION: ASUC is a medical emergency, predicting which patients will likely require colectomy is a very valuable tool in guiding therapeutic management. In our study the only variable significantly associated with colectomy was hypoalbuminaemia on day 3. However given the small study numbers a larger prospective study would be of value in identifying additional risk factors.
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    Open Access
    A prospective study of Clostridium difficile infection to investigate the impact of NAP1 strain in a tertiary referral hospital
    (2013) Rajabally, Muhammad Naayil; Watermeyer, Gill
    Includes abstract. Includes bibliographical references.