Interaction of gentamicin sulfate with alginate and consequences on the physico-chemical properties of alginate-containing biofilms

BACKGROUND: Alginate is one of the main extracellular polymeric substances (EPS) in biofilms of Cystic Fibrosis (CF) patients suffering from pulmonary infections. Gentamicin sulfate (GS) can strongly bind to alginate resulting in loss of pharmacological activity; however neither the mechanism nor its repercussion is fully understood. In this study, we investigated how GS modifies the alginate macromolecular network and its microenvironment. MATERIAL AND METHODS: Alginate gels of two different compositions (either enriched in guluronate units (G) or enriched in mannuronate units (M)) were crosslinked with Ca and exposed to GS at varying times and concentrations. The complexes formed were characterized via turbidimetry, mechanical tests, swelling assay, calorimetry techniques, nuclear magnetic resonance, Ca displacement, macromolecular probe diffusion and pH alteration. RESULTS: In presence of GS, the alginate network and its environment undergo a tremendous reorganization in terms of gel density, stiffness, diffusion property, presence and state of the water molecules. We noted that the intensity of those alterations is directly dependent on the polysaccharide motif composition (ratio M/G). CONCLUSION: Our results underline the importance of alginate as biofilm component, its pernicious role during antibiotherapy and could represent a potential macromolecular target to improve anti-infectious therapies

Learning-by-doing as an approach to teaching social entrepreneurship

Many studies have explored the use of learning-by-doing in higher education, but few have applied this to social entrepreneurship contexts and applications: this paper addresses this gap in the literature. Our programme involved students working with different stakeholders in an interactive learning environment to generate real revenue for social enterprises. Our results show that learning-by-doing enables students to develop their entrepreneurial skills and enhance their knowledge of social businesses. The findings also show that students became more effective at working in teams and in formulating and applying appropriate business strategies for the social enterprises. Overall, the learning-by-doing approach discussed in this paper is capable of developing the entrepreneurial skills of students, but there are challenges that need to be addressed if such an approach is to be effective

Supernatants from lymphocytes stimulated with Bacillus Calmette-Guerin can modify the antigenicity of tumours and stimulate allogeneic T-cell responses

BACKGROUND: Reduced expression of class 1 human leucocyte antigens (HLA1) is often a mechanism by which tumours evade surveillance by the host immune system. This is often associated with an immune function that is unable to mount appropriate responses against disease, which can result in a state that favours carcinogenesis. METHODS: In the current study, we have explored the effects of Bacillus Calmette-Guerin (BCG) on the cytokine output of leucocytes, which is a key determinant in generating antitumour action, and have also assessed the effect of these cytokine cocktails on HLA1 expression in solid tumour cell lines. RESULTS: BCG potently activated a broad range of leucocytes, and also enhanced the production of cytokines that were Th(1)-predominant. Supernatants from BCG-treated leucocytes significantly increased the expression of HLA1 on the surface of cancer cell lines, which correlated with increased cytolytic T-cell activity. We also showed that the increased HLA1 expression was associated with activation of intracellular signalling pathways, which was triggered by the increases in the Th(1)-cytokines interferon-γ and tumour necrosis factor-α, as counteracting their effects negated the enhancement. CONCLUSION: These studies reaffirm the role of BCG as a putative immunotherapy through their cytokine-modifying effects on leucocytes and their capacity to enhance tumour visibility

Preoperative Rectal Cancer Management: Wide International Practice Makes Outcome Comparison Challenging: Reply

In a letter to the editor Dr. Hottenrott provides valuable comments on our survey describing international preoperative rectal cancer management. In our opinion, three key messages are derived from our survey: First, most surgeons agree to neoadjuvant treatment when there is an increased risk of finding histologically positive circumferential margins. In addition, we found more than 40 other indications for neoadjuvant treatment (see our Table 4). This emphasizes the need for an international agreement, as different indications for neoadjuvant treatment will select noncomparable groups of patients in outcome studies. Second, we have shown (see our Table 6) that multidisciplinary team (MDT) meetings significantly influence several important decisions in preoperative rectal cancer management. Interestingly, centers with regular MDT have a higher rate of using magnetic resonance imaging (MRI) (Odds Ratio [OR] = 3.62) and consider a threatened circumferential resection margin (CRM) as indication for neoadjuvant treatment (OR = 5.67). We believe that MDT improves preoperative management of rectal cancer by increasing adherence to national guidelines. Similar discussions in international rectal cancer societies are needed aiming towards an international consensus statement. Finally, our survey revealed sparse use (35% of all cases) of MRI. The goal for the radiologic examination in rectal cancer is to explore the tumor’s relation to nearby anatomical structures. This evaluation will conclude with TNM staging, important for chemoradiotheraphy, surgical treatment, and prognosis. Magnetic resonance imaging has a central role in this evaluation and should be the first choice radiologic modality. Not only is MRI crucial in detection of TNM stage but also plays a central role in determination of the tumor’s distance to the mesorectal fascia and the CRM. Magnetic resonance imaging has moderate sensitivity on T1 and T2 tumors, and should be supplemented with rectal ultrasound

Expression and DNA methylation of TNF, IFNG and FOXP3 in colorectal cancer and their prognostic significance.

BACKGROUND: Colorectal cancer (CRC) progression is associated with suppression of host cell-mediated immunity and local immune escape mechanisms. Our aim was to assess the immune function in terms of expression of TNF, IFNG and FOXP3 in CRC. METHODS: Sixty patients with CRC and 15 matched controls were recruited. TaqMan quantitative PCR and methylation-specific PCR was performed for expression and DNA methylation analysis of TNF, IFNG and FOXP3. Survival analysis was performed over a median follow-up of 48 months. RESULTS: TNF was suppressed in tumour and IFNG was suppressed in peripheral blood mononuclear cells (PBMCs) of patients with CRC. Tumours showed enhanced expression of FOXP3 and was significantly higher when tumour size was >38 mm (median tumour size; P=0.006, Mann-Whitney U-test). Peripheral blood mononuclear cell IFNG was suppressed in recurrent CRC (P=0.01). Methylated TNFpromoter (P=0.003) and TNFexon1 (P=0.001) were associated with significant suppression of TNF in tumours. Methylated FOXP3cpg was associated with significant suppression of FOXP3 in both PBMC (P=0.018) and tumours (P=0.010). Reduced PBMC FOXP3 expression was associated with significantly worse overall survival (HR=8.319, P=0.019). CONCLUSIONS: We have detected changes in the expression of immunomodulatory genes that could act as biomarkers for prognosis and future immunotherapeutic strategies

The correlation between colorectal cancer rates of proliferation and apoptosis and systemic cytokine levels; plus their influence upon survival

Colorectal cancer development is associated with a shift in host immunity with suppression of the cell-mediated immune system (CMI) and a predominance of humoral immunity (HI). Tumour progression is also associated with increased rates of cell proliferation and apoptosis. The aim of this study was to investigate whether these factors correlate and have an influence upon prognosis. Long-term follow-up was performed on 40 patients with colorectal cancer who had levels of tumour necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-10 measured from stimulated blood cultures before surgery. Their archived tumour specimens were analysed to determine a Ki-67-derived proliferation index (PI) and a M30-derived apoptosis index (AI). Tumour necrosis factor-α levels negatively correlated to tumour proliferation (ρ=−0.697, P=0.01). Interleukin-10 levels had a positive correlation with tumour proliferation (ρ=0.452, P=0.05) and apoptosis (ρ=0.587, P=0.01). Patient survival correlates to tumour pathological stage (P=0.0038) and vascular invasion (P=0.0014). An AI⩽0.6% and TNF-α levels ⩾8148 pg ml−1 correlate to improved survival (P=0.032, P=0.021). Tumour proliferation and apoptosis correlate to progressive suppression of the CMI-associated cytokine TNF-α and to and higher levels of IL-10. Survival is dependent upon the histological stage of the tumour, vascular invasion, rates of apoptosis and proliferation and systemic immunity which are all interconnected

Experiment design and bacterial abundance control extracellular H2O2 concentrations during four series of mesocosm experiments

The extracellular concentration of H2O2 in surface aquatic environments is controlled by a balance between photochemical production and the microbial synthesis of catalase and peroxidase enzymes to remove H2O2 from solution. In any kind of incubation experiment, the formation rates and equilibrium concentrations of reactive oxygen species (ROSs) such as H2O2 may be sensitive to both the experiment design, particularly to the regulation of incident light, and the abundance of different microbial groups, as both cellular H2O2 production and catalase–peroxidase enzyme production rates differ between species. Whilst there are extensive measurements of photochemical H2O2 formation rates and the distribution of H2O2 in the marine environment, it is poorly constrained how different microbial groups affect extracellular H2O2 concentrations, how comparable extracellular H2O2 concentrations within large-scale incubation experiments are to those observed in the surface-mixed layer, and to what extent a mismatch with environmentally relevant concentrations of ROS in incubations could influence biological processes differently to what would be observed in nature. Here we show that both experiment design and bacterial abundance consistently exert control on extracellular H2O2 concentrations across a range of incubation experiments in diverse marine environments. During four large-scale (>1000 L) mesocosm experiments (in Gran Canaria, the Mediterranean, Patagonia and Svalbard) most experimental factors appeared to exert only minor, or no, direct effect on H2O2 concentrations. For example, in three of four experiments where pH was manipulated to 0.4–0.5 below ambient pH, no significant change was evident in extracellular H2O2 concentrations relative to controls. An influence was sometimes inferred from zooplankton density, but not consistently between different incubation experiments, and no change in H2O2 was evident in controlled experiments using different densities of the copepod Calanus finmarchicus grazing on the diatom Skeletonema costatum (<1 % change in [H2O2] comparing copepod densities from 1 to 10 L−1). Instead, the changes in H2O2 concentration contrasting high- and low-zooplankton incubations appeared to arise from the resulting changes in bacterial activity. The correlation between bacterial abundance and extracellular H2O2 was stronger in some incubations than others (R2 range 0.09 to 0.55), yet high bacterial densities were consistently associated with low H2O2. Nonetheless, the main control on H2O2 concentrations during incubation experiments relative to those in ambient, unenclosed waters was the regulation of incident light. In an open (lidless) mesocosm experiment in Gran Canaria, H2O2 was persistently elevated (2–6-fold) above ambient concentrations; whereas using closed high-density polyethylene mesocosms in Crete, Svalbard and Patagonia H2O2 within incubations was always reduced (median 10 %–90 %) relative to ambient waters

Development and validation of a patient reported outcome measure for health-related quality of life for locally recurrent rectal cancer: a multicentre, three-phase, mixed-methods, cohort study

Background Locally recurrent rectal cancer (LRRC) occurs in 5–10% of patients following previous treatment of rectal cancer. It has a significant impact on patients’ overall health-related quality of life (HrQoL). Major advances in surgical treatments have led to improved survival outcomes. However, due to the lack of disease-specific, validated patient-reported outcome measure (PROM), HrQoL, is variably assessed. The aim of this study is to develop a disease-specific, psychometrically robust, and validated PROM for use in LRRC. Methods A multicentre, three phase, mixed-methods, observational study was performed across five centres in the UK and Australia. Adult patients (>18 years old) with an existing or previously treated LRRC within the last 2 years were eligible to participate. Patients completed the proposed LRRC-QoL, EORTC QLQ-CR29, and FACT-C questionnaires. Scale structure was analysed using multi-trait scaling analysis and exploratory factor analysis, reliability was assessed using Cronbach's and the intra-class coefficient, convergent validity was assessed using Pearson's correlation, and known-groups comparison was assessed using the student t-test or ANOVA. Findings Between 01/03/2015 and 31/12/2019, 117 patients with a diagnosis of LRRC were recruited. The final scale structure of the LRRC-QoL consisted of nine multi-item scales (healthcare services, psychological impact, pain, urostomy-related symptoms, lower limb symptoms, stoma, sexual function, sexual interest, and urinary symptoms) and three single items. Cronbach's Alpha and Intraclass correlation values of >0.7 across the majority of scales supported overall reliability. Convergent validity was demonstrated between LRRC-QoL Pain Scale and FACT-C Physical Well Being scale (r = 0.528, p < 0.001), LRRC-QoL Psychological Impact scale with EORTC QLQ CR29 Body Image (r = 0.680, p < 0.001) and the FACT-C Emotional Well Being scale (r = 0.326, p < 0.001), and LRRC-QoL Urinary Symptoms scale with EORTC QLQ-CR29 Urinary Frequency scale (r = 0.310, p < 0.001). Known-groups validity was demonstrated for gender, disease location, treatment intent, and re-recurrent disease. Interpretation The LRRC-QoL has demonstrated robust psychometric properties and can be used in clinical and academic practice. Funding None