ß-cell-specific deletion of PFKFB3 restores cell fitness competition and physiological replication under diabetogenic stress.

HIF1α and PFKFB3 play a critical role in the survival of damaged ß-cells in type-2 diabetes while rendering ß-cells non-responsive to glucose stimulation. To discriminate the role of PFKFB3 from HIF1α in vivo, we generated mice with conditional ß-cell specific disruption of the Pfkfb3 gene on a human islet pancreatic polypeptide (hIAPP+/-) background and a high-fat diet (HFD) [PFKFB3ßKO + diabetogenic stress (DS)]. PFKFB3 disruption in ß-cells under DS led to selective purging of hIAPP-damaged ß-cells and the disappearance of insulin- and glucagon positive bihormonal cells. PFKFB3 disruption induced a three-fold increase in ß-cell replication as evidenced by minichromosome maintenance 2 protein (MCM2) expression. Unlike high-, lower DS or switch to restricted chow diet abolished HIF1α levels and reversed glucose intolerance of PFKFB3ßKO DS mice. Our data suggest that replication and functional recovery of ß-cells under DS depend on ß-cell competitive and selective purification of HIF1α and PFKFB3-positive ß-cells.

A retrospective case-cohort study comparing treatment outcomes in abacavir versus stavudine containing first line antiretroviral treatment regimens in children <3yrs old, at a paediatric programme based in Soweto, South Africa.

INTRODUCTION: The current World Health Organization guideline for first line antiretroviral therapy (ART) in HIV-infected children recommends the use of abacavir and lamivudine as nucleoside backbones and no longer includes stavudine. We compared treatment outcomes with abacavir (ABC) versus stavudine (d4T) in a cohort of HIV-1 infected children 6 and 12 months after antiretroviral therapy was initiated. METHODS: This was a retrospective case-cohort study, using programmatic data from children enrolled in the Paediatric Wellness Programme at the Perinatal HIV Research Unit in Soweto, South Africa between 2005 and 2013. Children on abacavir/stavudine who had initiated ART at age <3 years with a regimen including lamivudine and lopinavir/ritonavir and had at least one 6 or 12 month viral load result were eligible. All ABC cases identified were matched for age at ART initiation and gender to eligible d4T controls (1:2). Outcomes analysed at 6 and 12 months post ART initiation included virological failure, mortality, immunological failure and anthropometry. Chi-square tests compared categorical measures while Kruskal-Wallis compared continuous measures. RESULTS: We identified 57 eligible ABC cases and selected 114 matched d4T controls. Overall, 57% were females and 89% started treatment at age <1year. The median age at ART initiation was 3.11 (IQR: 1.98-6.05) months. There was no difference in the proportion of children virologically suppressed between the groups at 6 (ABC 54.5% vs. d4T 67.0%, p = 0.125) and 12 (ABC 66.7% vs. d4T 71.6%, p = 0.53) months post ART-initiation. The proportion of children with adherence levels >90% for ABC and d4T were similar too (95% in ABC vs. 86% in d4T, p = 0.10). The proportion of children who died over 12 months was 3.5% in the ABC and 7.9% in the d4T group (p = 0.27). Similarly, the anthropometric measures were comparable. CONCLUSIONS: It is reassuring that in the short term, in this group of patients, the treatment outcomes were similar.

The effects of the natural enzyme, Pectinex Ultra SP-L, on human cell cultures and bacterial biofilms in vitro.

BACKGROUND: Pectinex Ultra SP-L (Pectinex) is a microbial-derived enzyme that is used in the food industry and that has been shown to inhibit bacterial biofilms. It has been suggested that Pectinex may be useful in the management of biofilm-related bacterial infections and therefore warrants further investigation in this regard. The aim of this study was to investigate the cytotoxicity of Pectinex on cervical adenocarcinoma cells (HeLa), lymphocytes and neutrophils. Cell viability and morphology were assessed using an in vitro spectrophotometric MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay and polarization-optical transmitted light differential interference contrast microscopy. This study also investigated the antibacterial and antibiofilm actions of Pectinex, alone and in combination with antibiotics, on standard and clinical cultures of Staphylococcus aureus and Pseudomonas aeruginosa. Minimum inhibitory (MIC) and bactericidal (MBC) concentrations were determined using p-iodo-nitrotetrazolium violet staining of bacterial cultures and regrowth of subcultures. Biofilm biomass and cell viability were quantified spectrophotometrically after staining with crystal violet and MTT. RESULTS: The IC50 (±SEM) of Pectinex was 193.9 (±22.2) PGU/ml for HeLa cells, 383.4 (±81.5) and 629.6 (±62.8) PGU/ml for fMLP-stimulated and non-stimulated lymphocytes respectively, and 245.9 (±9.4) and 529.7 (±40.7) PGU/ml for fMLP-stimulated and non-stimulated neutrophils, respectively. Induced morphological features characteristic of apoptosis and necrosis included cell membrane blebs and vacuolization in HeLa cells, clumping in lymphocytes, as well as shrunken rounded cells, apoptotic bodies and debris in all cultures. Pectinex (7.42 - 950 PGU/ml-1) was not bactericidal. In clinical cultures of Staphylococcus aureus, co-administration of Pectinex was associated with a 28.0% increase in both the MIC and MBC of amoxicillin-clavulanate. In clinical cultures of P. aeruginosa, there was an 89.0% and 92.8% increase in the MIC and MBC of ciprofloxacin, respectively. Pectinex ≤ 118.75 PGU/ml-1 and incubation periods ≥ 6 h were associated with increased biomass and cell viability in S. aureus or P. aeruginosa biofilms. CONCLUSIONS: Pectinex appeared to antagonize the antibacterial effects of amoxicillin-clavulanate and ciprofloxacin and furthermore demonstrated significant cytotoxicity. It was therefore deemed unsuitable for the management of either planktonic or biofilm phenotypes of S. aureus or P. aeruginosa.

Assessing adherence to the 2010 antiretroviral guidelines at the antiretroviral rollout clinic in 1 military hospital, South Africa: a retrospective, cross sectional study.

BACKGROUND: HIV research is a therapeutic area for which well-defined population-specific treatment and prophylaxis guidelines exist. However, there are limited objective, evidence-based data for assessing adherence to these guidelines. OBJECTIVE: To conduct a retrospective, cross sectional study of adult HIV-infected patients receiving treatment at the antiretroviral (ARV) roll-out clinic of the Infectious Diseases Clinic Pharmacy at 1 Military Hospital (1MH) over a period of 3 years to assess clinicians' adherence to the 2010 ARV guidelines. METHODS: Pharmacy files from the pool of adult patients receiving treatment at the ARV roll-out clinic between 1 April 2009 and 31 March 2012 were selected. Variables used to establish adherence were assessed through evaluation of pharmacy scripts and laboratory tests. RESULTS: In accordance with the ARV guidelines, we found a switch in the first-line regimen from stavudine to tenofovir in the period following implementation. There was no difference in baseline blood tests conducted, suggesting that clinicians were recommending a standardised test panel. Notably, similar blood tests were routinely done during follow-up visits, despite no indication for doing so. While the number of blood tests was found to decrease over time, the type of blood tests requested for specific treatment regimens was not in accordance with ARV guidelines. CONCLUSION: We used an evidence-based approach to critically assess variations from the delineated ARV guidelines. Adherence to clinical guidelines at 1MH, while demonstrating improvement in patient outcomes, highlighted the need for increased vigilance in monitoring failure of prescribers to comply with ARV guidelines.