48 research outputs found
Colonic epithelial ion transport is not affected in patients with diverticulosis
<p>Abstract</p> <p>Background</p> <p>Colonic diverticular disease is a bothersome condition with an unresolved pathogenesis. It is unknown whether a neuroepithelial dysfunction is present. The aim of the study was two-fold; (1) to investigate colonic epithelial ion transport in patients with diverticulosis and (2) to adapt a miniaturized Modified Ussing Air-Suction (MUAS) chamber for colonic endoscopic biopsies.</p> <p>Methods</p> <p>Biopsies were obtained from the sigmoid part of the colon. 86 patients were included. All patients were referred for colonoscopy on suspicion of neoplasia and they were without pathological findings at colonoscopy (controls) except for diverticulosis in 22 (D-patients). Biopsies were mounted in MUAS chambers with an exposed area of 5 mm<sup>2</sup>. Electrical responses to various stimulators and inhibitors of ion transport were investigated together with histological examination. The MUAS chamber was easy to use and reproducible data were obtained.</p> <p>Results</p> <p>Median basal short circuit current (SCC) was 43.8 μA·cm<sup>-2 </sup>(0.8 – 199) for controls and 59.3 μA·cm<sup>-2 </sup>(3.0 – 177.2) for D-patients. Slope conductance was 77.0 mS·cm<sup>-2 </sup>(18.6 – 204.0) equal to 13 Ω·cm<sup>2 </sup>for controls and 96.6 mS·cm<sup>-2 </sup>(8.4 – 191.4) equal to 10.3 Ω·cm<sup>2 </sup>for D-patients. Stimulation with serotonin, theophylline, forskolin and carbachol induced increases in SCC in a range of 4.9 – 18.6 μA·cm<sup>-2</sup>, while inhibition with indomethacin, bumetanide, ouabain and amiloride decreased SCC in a range of 6.5 – 27.4 μA·cm<sup>-2</sup>, and all with no significant differences between controls and D-patients. Histological examinations showed intact epithelium and lamina propria before and after mounting for both types of patients.</p> <p>Conclusion</p> <p>We conclude that epithelial ion transport is not significantly altered in patients with diverticulosis and that the MUAS chamber can be adapted for studies of human colonic endoscopic biopsies.</p
Anti-biofilm activities from marine cold adapted bacteria against staphylococci and Pseudomonas aeruginosa
Microbial biofilms have great negative impacts on the world’s economy and pose serious
problems to industry, public health and medicine. The interest in the development of
new approaches for the prevention and treatment of bacterial adhesion and biofilm
formation has increased. Since, bacterial pathogens living in biofilm induce persistent
chronic infections due to the resistance to antibiotics and host immune system.
A viable approach should target adhesive properties without affecting bacterial vitality
in order to avoid the appearance of resistant mutants. Many bacteria secrete antibiofilm
molecules that function in regulating biofilm architecture or mediating the
release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted
marine bacteria represent an untapped reservoir of biodiversity able to synthesize a
broad range of bioactive compounds, including anti-biofilm molecules. The anti-biofilm
activity of cell-free supernatants derived from sessile and planktonic cultures of coldadapted
bacteria belonging to Pseudoalteromonas, Psychrobacter, and Psychromonas
species were tested against Staphylococcus aureus, Staphylococcus epidermidis, and
Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected
supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able
to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary
physico-chemical characterization of supernatants was also performed, and these
analyses highlighted the presence of molecules of different nature that act by inhibiting
biofilm formation. Some of them are also able to impair the initial attachment of the
bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm
surfactant molecules. The described ability of cold-adapted bacteria to produce effective
anti-biofilm molecules paves the way to further characterization of the most promising
molecules and to test their use in combination with conventional antibiotics