The frequency of microscopic and focal active colitis in patients with irritable bowel syndrome

<p>Abstract</p> <p>Background</p> <p>Irritable bowel syndrome (IBS) is a chronic functional bowel disorder. The frequency of microscopic colitis and focal active colitis in the colonic mucosa has been investigated in IBS patients.</p> <p>Methods</p> <p>Between June 2007 and September 2010, 378 patients (between 16 and 84 years) were recruited prospectively. Of these 378 patients, 226 patients were diagnosed with IBS using the Rome III criteria. 152 control patients were also enrolled who were undergoing colonoscopy for colorectal cancer screening or investigation of anemia. Histopathological abnormalities identified during colonoscopy were compared between the IBS and control groups.</p> <p>Results</p> <p>The average age of the IBS group was 46.13 ± 14.16 years and and the average age of the control group was 57.01 ± 13.07 years. The prevalence of microscopic colitis (MC) in the diarrhea predominant and the mixed subgroup of IBS patients was 4.32% (7/162) whereas in all IBS patients, the prevalence was 3.09% (7/226). MC was not found in the 152 control cases, (p = 0.045). Lymphocytic colitis was seen in 7 IBS patients, with 1 case in the mixed group and 6 cases in the diarrhea group and there was a significant difference in the frequency of lymphocytic colitis between the IBS subgroups (p < 0.01). Focal active colitis was found in 6.6% (15/226) of the IBS patients and in none of the controls (p < 0.01), and there was no differences between IBS subtypes.</p> <p>Conclusion</p> <p>Microscopic colitis was more often found in the diarrhea predominant/mixed subgroups of IBS patients and in patients who were older women. In patients who are older woman with non-constipated IBS, it may be reasonable to perform a biopsy to screen for microscopic colitis. Focal active colitis was significantly increased in patients with IBS compared to controls.</p

Investigation of flow structure around a horizontal cylinder at different elevations in shallow water

Flow characteristics around a horizontal circular cylinder were investigated in shallow water. The diameter of circular cylinder, the height of shallow water and free stream velocity were kept constant during the experiments as D=30 mm, hw=60 mm and U=167 mm/s, respectively. Particle Image Velocimetry (PIV) was used to measure instantaneous and time-averaged velocity vector fields in the near wake region. In order to investigate the effect of immersion, the cylinder was placed at eight different elevations (hD) between bottom and free surface (from 7.5 to 60 mm with 7.5 mm increments). Instantaneous and time-averaged velocity vector field, corresponding streamline patterns and Reynolds stress correlation were used to analyze the behavior of the flow downstream of horizontal cylinder. The mean velocity vector field, corresponding streamline topology and Reynolds stress correlation were obtained using 500 instantaneous images. As the immersion level ratio (hD/D) increases, the magnitude of jet-like flow velocity goes up ranged from hD/D=0.25-1. Time averaged flow characteristics show that there is a difference between primary and developing circulation bubble depending on direction of rotation. This occurrence causes the entrainment and this stimulates the momentum transfer between the core and wake flow region for hD/D=1 and 2 cases. © 2014 Elsevier Ltd