<p>ABSTRACT</p><p>In the western world colitis is a common chronic disease and in Sweden the prevalence is around 1%. If a patient has bloody diarrhea it is probably ulcerative proctocolitis or Crohn’s disease, whereas if the diarrhea is watery, it is microscopic colitis. For a diagnosis, the patient has to do a colonoscopy and a colonic biopsy sample has to be taken. The biopsy sample will be sent to a laboratory for sectioning, staining and microscopic analysis.</p><p>In this study we compared the effects of short and long dehydration time of the sample before the sectioning. We also compared staining with Alcianblue/Van Gieson and Van Gieson alone.</p><p>Our results showed that a short dehydration time was a milder treatment and made it easier to section the biopsy sample. The comparison of the two methods was unsuccessful because the staining with Alcianblue/Van Gieson failed.</p>

ABSTRACT In the western world colitis is a common chronic disease and in Sweden the prevalence is around 1%. If a patient has bloody diarrhea it is probably ulcerative proctocolitis or Crohn’s disease, whereas if the diarrhea is watery, it is microscopic colitis. For a diagnosis, the patient has to do a colonoscopy and a colonic biopsy sample has to be taken. The biopsy sample will be sent to a laboratory for sectioning, staining and microscopic analysis. In this study we compared the effects of short and long dehydration time of the sample before the sectioning. We also compared staining with Alcianblue/Van Gieson and Van Gieson alone. Our results showed that a short dehydration time was a milder treatment and made it easier to section the biopsy sample. The comparison of the two methods was unsuccessful because the staining with Alcianblue/Van Gieson failed.

Colonoscopy provides a minimally invasive tool for examining and treating the colon without surgery, but current endoscope designs still cause a degree of pain and injury to the colon wall. The most common colonoscopies are long tubes inserted through the rectum, with locomotion actuators, fiber optic lights, cameras, and biopsy tools on the distal end. The stiffness required to support these tools makes it difficult for the scopes to navigate the twisted path of the colon without damaging the inside wall of the colon or distorting its shape. In addition, little is known about how sharp and forceful endoscopes can be without accidentally cutting into tissue during navigation. In order to solve the requirements of stiffness (to support tools) and flexibility (to navigate turns), we expanded on a design by Zehel et al. [49], who proposed surrounding a flexible endoscope with an external exoskeleton structure, with controllable stiffness. The exoskeleton structure is comprised of rigid, articulating tubular units, which are stiffened or relaxed by four control cables. The stiffened or locked exoskeleton structure aids navigation and provides stability for the endoscope when it protrudes beyond the exoskeleton structure for examination and procedures. This research determined the design requirements of such an exoskeleton structure and simulated its behavior in a sigmoid colon model. To predict just how pointed an endoscope can be without damaging tissue under a given force, we extrapolated a strength model of the descending colon from published stress-strain curves of human colon tissue. Next we analyzed how friction, cable forces, and unit angles interact to hold the exoskeleton structure in a locked position. By creating two- and three-dimensional models of the exoskeleton structure, we optimized the dimensions of the units of an exoskeleton structure (diameter, thickness, and leg angle) and cable holders ( cable attachment location) to achieve the turns of the sigmoid colon, while still remaining lockable. Models also predicted the loss of force over the exoskeleton structure due to curving, further determining the required cable angles and friction between units. Finally we determined how the stiffness of the endoscope stem affected locking ability and wear inside the exoskeleton structure. / Ph. D.