Colon, Sigmoid: A segment of the COLON between the RECTUM and the descending colon.Sigmoid Diseases: Pathological processes in the SIGMOID COLON region of the large intestine (INTESTINE, LARGE).Sigmoid Neoplasms: Tumors or cancer of the SIGMOID COLON.Intestinal Volvulus: A twisting in the intestine (INTESTINES) that can cause INTESTINAL OBSTRUCTION.Diverticulitis, Colonic: Inflammation of the COLONIC DIVERTICULA, generally with abscess formation and subsequent perforation.Colonic Neoplasms: Tumors or cancer of the COLON.Diverticulum, Colon: A pouch or sac opening from the COLON.Colon, Descending: The segment of LARGE INTESTINE between TRANSVERSE COLON and the SIGMOID COLON.Cranial Sinuses: Large endothelium-lined venous channels situated between the two layers of DURA MATER, the endosteal and the meningeal layers. They are devoid of valves and are parts of the venous system of dura mater. Major cranial sinuses include a postero-superior group (such as superior sagittal, inferior sagittal, straight, transverse, and occipital) and an antero-inferior group (such as cavernous, petrosal, and basilar plexus).Colostomy: The surgical construction of an opening between the colon and the surface of the body.Colonic Diseases: Pathological processes in the COLON region of the large intestine (INTESTINE, LARGE).Colectomy: Excision of a portion of the colon or of the whole colon. (Dorland, 28th ed)Intestinal Perforation: Opening or penetration through the wall of the INTESTINES.Intestinal Obstruction: Any impairment, arrest, or reversal of the normal flow of INTESTINAL CONTENTS toward the ANAL CANAL.Colonoscopy: Endoscopic examination, therapy or surgery of the luminal surface of the colon.Mesocolon: The fold of peritoneum by which the COLON is attached to the posterior ABDOMINAL WALL.Rectum: The distal segment of the LARGE INTESTINE, between the SIGMOID COLON and the ANAL CANAL.Colon, Ascending: The segment of LARGE INTESTINE between the CECUM and the TRANSVERSE COLON. It passes cephalad from the cecum to the caudal surface of the right lobe of the LIVER where it bends sharply to the left, forming the right colic flexure.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Intestinal Fistula: An abnormal anatomical passage between the INTESTINE, and another segment of the intestine or other organs. External intestinal fistula is connected to the SKIN (enterocutaneous fistula). Internal intestinal fistula can be connected to a number of organs, such as STOMACH (gastrocolic fistula), the BILIARY TRACT (cholecystoduodenal fistula), or the URINARY BLADDER of the URINARY TRACT (colovesical fistula). Risk factors include inflammatory processes, cancer, radiation treatment, and surgical misadventures (MEDICAL ERRORS).Colon, Transverse: The segment of LARGE INTESTINE between ASCENDING COLON and DESCENDING COLON. It passes from the RIGHT COLIC FLEXURE across the ABDOMEN, then turns sharply at the left colonic flexure into the descending colon.Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Adenocarcinoma: A malignant epithelial tumor with a glandular organization.Cecal Neoplasms: Tumors or cancer of the CECUM.Rectal Neoplasms: Tumors or cancer of the RECTUM.Sigmoidoscopy: Endoscopic examination, therapy or surgery of the sigmoid flexure.Laparoscopy: A procedure in which a laparoscope (LAPAROSCOPES) is inserted through a small incision near the navel to examine the abdominal and pelvic organs in the PERITONEAL CAVITY. If appropriate, biopsy or surgery can be performed during laparoscopy.46, XX Disorders of Sex Development: Congenital conditions in individuals with a female karyotype, in which the development of the gonadal or anatomical sex is atypical.Gastrointestinal Motility: The motor activity of the GASTROINTESTINAL TRACT.Sinus Thrombosis, Intracranial: Formation or presence of a blood clot (THROMBUS) in the CRANIAL SINUSES, large endothelium-lined venous channels situated within the SKULL. Intracranial sinuses, also called cranial venous sinuses, include the superior sagittal, cavernous, lateral, petrous sinuses, and many others. Cranial sinus thrombosis can lead to severe HEADACHE; SEIZURE; and other neurological defects.Diverticulitis: Inflammation of a DIVERTICULUM or diverticula.Intestine, Large: A segment of the LOWER GASTROINTESTINAL TRACT that includes the CECUM; the COLON; and the RECTUM.Colorectal Neoplasms: Tumors or cancer of the COLON or the RECTUM or both. Risk factors for colorectal cancer include chronic ULCERATIVE COLITIS; FAMILIAL POLYPOSIS COLI; exposure to ASBESTOS; and irradiation of the CERVIX UTERI.Subcutaneous Emphysema: Presence of air or gas in the subcutaneous tissues of the body.Barium Sulfate: A compound used as an x-ray contrast medium that occurs in nature as the mineral barite. It is also used in various manufacturing applications and mixed into heavy concrete to serve as a radiation shield.Cerebral Veins: Veins draining the cerebrum.Enema: A solution or compound that is introduced into the RECTUM with the purpose of cleansing the COLON or for diagnostic procedures.HT29 Cells: Human colonic ADENOCARCINOMA cells that are able to express differentiation features characteristic of mature intestinal cells such as the GOBLET CELLS.Intestinal Polyps: Discrete abnormal tissue masses that protrude into the lumen of the INTESTINE. A polyp is attached to the intestinal wall either by a stalk, pedunculus, or by a broad base.Megacolon: Dilatation of the COLON, often to alarming dimensions. There are various types of megacolon including congenital megacolon in HIRSCHSPRUNG DISEASE, idiopathic megacolon in CONSTIPATION, and TOXIC MEGACOLON.Radiography, Abdominal: Radiographic visualization of the body between the thorax and the pelvis, i.e., within the peritoneal cavity.Colonic Diseases, Functional: Chronic or recurrent colonic disorders without an identifiable structural or biochemical explanation. The widely recognized IRRITABLE BOWEL SYNDROME falls into this category.Mesenteric Cyst: A rare intra-abdominal tumor in the MESENTERY. Mesenteric cysts are usually benign and can be very large fluid-filled (2000 mL) lesions.Azoxymethane: A potent carcinogen and neurotoxic compound. It is particularly effective in inducing colon carcinomas.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Diverticulum: A pouch or sac developed from a tubular or saccular organ, such as the GASTROINTESTINAL TRACT.Adenoma: A benign epithelial tumor with a glandular organization.Colitis, Ulcerative: Inflammation of the COLON that is predominantly confined to the MUCOSA. Its major symptoms include DIARRHEA, rectal BLEEDING, the passage of MUCUS, and ABDOMINAL PAIN.Anastomosis, Surgical: Surgical union or shunt between ducts, tubes or vessels. It may be end-to-end, end-to-side, side-to-end, or side-to-side.Surgical Stapling: A technique of closing incisions and wounds, or of joining and connecting tissues, in which staples are used as sutures.Prolapse: The protrusion of an organ or part of an organ into a natural or artificial orifice.Cecum: The blind sac or outpouching area of the LARGE INTESTINE that is below the entrance of the SMALL INTESTINE. It has a worm-like extension, the vermiform APPENDIX.Colitis, Ischemic: Inflammation of the COLON due to colonic ISCHEMIA resulting from alterations in systemic circulation or local vasculature.Transverse Sinuses: The two large endothelium-lined venous channels that begin at the internal occipital protuberance at the back and lower part of the CRANIUM and travels laterally and forward ending in the internal jugular vein (JUGULAR VEINS). One of the transverse sinuses, usually the right one, is the continuation of the SUPERIOR SAGITTAL SINUS. The other transverse sinus is the continuation of the straight sinus.Gangrene: Death and putrefaction of tissue usually due to a loss of blood supply.Colitis: Inflammation of the COLON section of the large intestine (INTESTINE, LARGE), usually with symptoms such as DIARRHEA (often with blood and mucus), ABDOMINAL PAIN, and FEVER.Constipation: Infrequent or difficult evacuation of FECES. These symptoms are associated with a variety of causes, including low DIETARY FIBER intake, emotional or nervous disturbances, systemic and structural disorders, drug-induced aggravation, and infections.Rectal Diseases: Pathological developments in the RECTUM region of the large intestine (INTESTINE, LARGE).Surgically-Created Structures: Organs or parts of organs surgically formed from nearby tissue to function as substitutes for diseased or surgically removed tissue.Colonoscopes: Specially designed endoscopes for visualizing the interior surface of the colon.Colonic Polyps: Discrete tissue masses that protrude into the lumen of the COLON. These POLYPS are connected to the wall of the colon either by a stalk, pedunculus, or by a broad base.Digestive System Surgical Procedures: Surgery performed on the digestive system or its parts.Mastoid: The posterior part of the temporal bone. It is a projection of the petrous bone.Gastrointestinal Hemorrhage: Bleeding in any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM.Fatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.Mediastinal Emphysema: Presence of air in the mediastinal tissues due to leakage of air from the tracheobronchial tree, usually as a result of trauma.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Cystoscopes: Endoscopes for visual examination of the urinary bladder.Pneumoperitoneum: A condition with trapped gas or air in the PERITONEAL CAVITY, usually secondary to perforation of the internal organs such as the LUNG and the GASTROINTESTINAL TRACT, or to recent surgery. Pneumoperitoneum may be purposely introduced to aid radiological examination.Brachytherapy: A collective term for interstitial, intracavity, and surface radiotherapy. It uses small sealed or partly-sealed sources that may be placed on or near the body surface or within a natural body cavity or implanted directly into the tissues.1,2-Dimethylhydrazine: A DNA alkylating agent that has been shown to be a potent carcinogen and is widely used to induce colon tumors in experimental animals.Neoplasms, Multiple Primary: Two or more abnormal growths of tissue occurring simultaneously and presumed to be of separate origin. The neoplasms may be histologically the same or different, and may be found in the same or different sites.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Neurokinin A: A mammalian neuropeptide of 10 amino acids that belongs to the tachykinin family. It is similar in structure and action to SUBSTANCE P and NEUROKININ B with the ability to excite neurons, dilate blood vessels, and contract smooth muscles, such as those in the BRONCHI.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Urinary Bladder Fistula: An abnormal passage in the URINARY BLADDER or between the bladder and any surrounding organ.Thigh: The portion of the leg in humans and other animals found between the HIP and KNEE.Abdomen, Acute: A clinical syndrome with acute abdominal pain that is severe, localized, and rapid in onset. Acute abdomen may be caused by a variety of disorders, injuries, or diseases.Cecal Diseases: Pathological developments in the CECUM.Endoscopy, Gastrointestinal: Endoscopic examination, therapy or surgery of the gastrointestinal tract.Appendiceal Neoplasms: Tumors or cancer of the APPENDIX.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Ileum: The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.Melena: The black, tarry, foul-smelling FECES that contain degraded blood.