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Gastrointestinal Function and Toxicology in Canines
Published in Shayne C. Gad, Toxicology of the Gastrointestinal Tract, 2018
The stomach has three motor functions. The first of these is storage of food until it can be processed in the lower gastrointestinal tract. The next is to mix food with gastric secretions turning it into chyme. The third and last is to slowly empty the chyme into the small intestine at a rate which permits adequate digestion and absorption by the small bowel. If the stomach is empty intense contractions can occur and these contractions generally start 12–24 hours after the last ingestion of food. These contractions are aborally moving rhythmic peristaltic contractions occurring in the body of the stomach that can sustain themselves in tetany for periods of time of up to 3 minutes. These contractions can be influenced by low levels of blood sugar. When the stomach contains food, constrictor or mixing waves originate in the middle portion of the stomach wall and travel toward the antrum of the stomach at a frequency of about one every 15–20 seconds. As these waves move from the body to the antrum, they become ring-like constrictions of the gastric wall and of increasingly greater intensity that force under high pressure the gastric contents toward the pylorus. These contractions can create forces of 50–70 cm of water pressure and each time a peristaltic wave moves toward the antrum, it presses firmly against the antral contents. However, the opening of the pylorus is sufficiently small enough in size that only a few milliliters of chyme are introduced into the duodenum with each compressing peristaltic wave. In its normal resting state, the pyloric sphincter usually remains sufficiently open for liquids to empty from the stomach without resistance. However, this formidable barrier prevents the passage of food into the small bowel until it has been adequately mixed. Keep in mind that as each peristaltic wave approaches the pylorus, the pyloric muscle itself contracts. This activity inhibits the expulsion of gastric contents into the duodenum and accordingly antral contents are ejected upstream through a peristaltic ring back toward the body of the stomach. This process is repeated over and over, permitting a great degree of mixing in the stomach and reduction of the food mass to a fluid-like consistency. As the stomach slowly begins to empty, contractions initiate further up the body of the stomach wall, gradually isolating the food into the lower portions of the stomach. This mixing and propelling activity is sometimes referred to as the pyloric pump.
Electrocoagulation Of Vascular Abnormalities Of The Large Bowel
Published in John P. Papp, Endoscopie Control of Gastrointestinal Hemorrhage, 2019
Early angiographic studies paid little attention to diseases associated with the vascular abnormality.4, 16-18 Boss and Rosenbaum,19 in 1971, reported the case of a 77-year-old man who had continuous gastrointestinal bleeding of obscure cause which was present for the 6 years prior to his death. He had severe aortic stenosis, and at autopsy it was clear that the bleeding was coming from the right colon. In 1974, Galloway et al.20 showed the cause of bleeding in patients with aortic stenosis was a vascular abnormality in the right colon. Angiographic studies demonstrated the lesions in three consecutive patients with lower gastrointestinal tract bleeding of unknown cause. Right colectomy resulted in cessation of bleeding. It is interesting that one of three patients had idiopathic hypertrophic subaortic stenosis. The observation was important because prior to that time, it was thought by some that only patients with calcific aortic stenosis were subject to increased gastrointestinal bleeding. An association between the colonoscopically visualized vascular abnormality and aortic stenosis was made by Rogers and Adler in 1976.7 In addition, an association was made between other types of cardiac and vascular disease, including mitral insufficiency, atherosclerotic vascular disease, and coronary artery disease. In 1977, Baum et al.21 reported 34 patients who had a vascular abnormality of the right large bowel, 17 of whom had a history of cardiac disease. Nine had a clinical diagnosis of aortic stenosis. Three had combined valvular disease, and five had atherosclerotic coronary disease. In 1979, Gelfand et al.22 reported five patients with aortic stenosis who had multiple, massive hemorrhages from the lower gastrointestinal tract which defied diagnosis by conventional methods. Mesenteric angiography, however, disclosed the origin of bleeding. In four patients, vascular abnormalities were found in the right colon and one in the jejunum. Right hemicolectomy and partial jejunectomy resulted in a cure in all. Boley et al.23 reported nine patients with aortic stenosis among 32 in whom vascular abnormalities of the right colon were identified by angiography. In 1980, Rogers reported a colonoscopic series of 24 patients with small vascular abnormalities in the colon.24 Twenty of the 24 had associated cardiac, vascular, or pulmonary disease. Three of them had aortic stenosis.
Utility of repeat colonoscopy within 1 year: a patient-level analysis
Published in Baylor University Medical Center Proceedings, 2023
Busara Songtanin, Abbie Evans, Sebastian Sanchez, Vanessa Costilla, Kenneth Nugent
There are alternative approaches, such as computed tomography (CT) of the colon, to evaluate the lower gastrointestinal tract. The advantages of CT colonography over colonoscopy include shorter procedure time, no sedation, and less risk of operative complications. It has a lower risk of bowel perforation than standard colonoscopy. The reported sensitivities of CT colonography and colonoscopy in detecting adenomas >6 mm are 73% to 98% and 75% to 93%, respectively; these results indicate that these two procedures have similar performance characteristics.7 The overall “miss” rate of colonoscopy in detecting polyps, adenomas, and advanced adenomas (defined as an adenoma ≥10 mm in size, an adenoma with tubulovillous or villous histology, and an adenoma with high-grade dysplasia) is 5% to 17%.8 At present, colonoscopy remains the standard for lower gastrointestinal evaluation, and CT colonography should be used only in patients who have increased risk for colonoscopic procedures or prefer an alternative to repeat colonoscopy.
DIgestive COmplications in DIabetes – the DICODI population study
Published in Scandinavian Journal of Gastroenterology, 2023
Moeen Ud-din, Bassam Karout, Wiktoria M. Torbé, Johan Lunding, Anne-Marie Wegeberg, Asbjørn M. Drewes, Christina Brock, Per M. Hellström
The results of the Focus Group data indicated that symptoms from the upper gastrointestinal tract was a major concern among diabetics, while symptoms from the lower gastrointestinal tract were of less prominence, though not eligible. Against this background we chose to use a collection of validated diagnostic questionnaires in order to distinctly separate various diabetic complications and coherent diseases that can develop as late complications with the help of the patient’s own reports. The questionnaires to be used are:Gastroparesis Cardinal Symptom Index (GCSI)Gastrointestinal Symptom Rating Scale (GSRS)Celiac Symptom Index (CSI)Pancreatic Exocrine Insufficiency Questionnaire (PEIQ)
Dysbiotic human oral microbiota alters systemic metabolism via modulation of gut microbiota in germ-free mice
Published in Journal of Oral Microbiology, 2022
Kyoko Yamazaki, Eiji Miyauchi, Tamotsu Kato, Keisuke Sato, Wataru Suda, Takahiro Tsuzuno, Miki Yamada-Hara, Nobuo Sasaki, Hiroshi Ohno, Kazuhisa Yamazaki
The oral cavity and lower gastrointestinal tract are anatomically connected, and most symbiotic microbial communities in humans inhabit these regions. The saliva contains a significant number of oral microbiota that are constantly swallowed into the gastrointestinal tract. However, the effect of the oral microbiota on the gut microbiota and the subsequent negative impact on systemic health has generally been disregarded, except in the case of cirrhosis [1], inflammatory bowel disease [2], and colorectal cancer [3]. Furthermore, because there is a barrier between the oral cavity and intestinal tract, such as gastric acid and bile acid, most swallowed oral microbiota are considered to be killed and never reach the intestinal tract. However, it is increasingly evident that a significant amount of the oral microbiota flow into the gut and are members of the gut microbiota in systemically healthy individuals [4]. Thus, unhealthy oral microbiota, for example, those observed in periodontitis patients, may distinctly affect the gut microbiota and subsequent systemic conditions.