Barrett Esophagus: A condition with damage to the lining of the lower ESOPHAGUS resulting from chronic acid reflux (ESOPHAGITIS, REFLUX). Through the process of metaplasia, the squamous cells are replaced by a columnar epithelium with cells resembling those of the INTESTINE or the salmon-pink mucosa of the STOMACH. Barrett's columnar epithelium is a marker for severe reflux and precursor to ADENOCARCINOMA of the esophagus.Esophagus: The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.Esophageal Neoplasms: Tumors or cancer of the ESOPHAGUS.Metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.Precancerous Conditions: Pathological processes that tend eventually to become malignant. (From Dorland, 27th ed)Genes, MCC: Tumor suppressor genes located in the 5q21 region on the long arm of human chromosome 5. The mutation of these genes is associated with the formation of colorectal cancer (MCC stands for mutated in colorectal cancer).Adenocarcinoma: A malignant epithelial tumor with a glandular organization.Cardia: That part of the STOMACH close to the opening from ESOPHAGUS into the stomach (cardiac orifice), the ESOPHAGOGASTRIC JUNCTION. The cardia is so named because of its closeness to the HEART. Cardia is characterized by the lack of acid-forming cells (GASTRIC PARIETAL CELLS).Gastroesophageal Reflux: Retrograde flow of gastric juice (GASTRIC ACID) and/or duodenal contents (BILE ACIDS; PANCREATIC JUICE) into the distal ESOPHAGUS, commonly due to incompetence of the LOWER ESOPHAGEAL SPHINCTER.Endoscopy, Gastrointestinal: Endoscopic examination, therapy or surgery of the gastrointestinal tract.Esophagoscopy: Endoscopic examination, therapy or surgery of the esophagus.Disease Progression: The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Esophagogastric Junction: The area covering the terminal portion of ESOPHAGUS and the beginning of STOMACH at the cardiac orifice.Esophagectomy: Excision of part (partial) or all (total) of the esophagus. (Dorland, 28th ed)Mucous Membrane: An EPITHELIUM with MUCUS-secreting cells, such as GOBLET CELLS. It forms the lining of many body cavities, such as the DIGESTIVE TRACT, the RESPIRATORY TRACT, and the reproductive tract. Mucosa, rich in blood and lymph vessels, comprises an inner epithelium, a middle layer (lamina propria) of loose CONNECTIVE TISSUE, and an outer layer (muscularis mucosae) of SMOOTH MUSCLE CELLS that separates the mucosa from submucosa.Hernia, Hiatal: STOMACH herniation located at or near the diaphragmatic opening for the ESOPHAGUS, the esophageal hiatus.Esophageal Diseases: Pathological processes in the ESOPHAGUS.Pharmacy Administration: The business and managerial aspects of pharmacy in its broadest sense.Esophageal Stenosis: A stricture of the ESOPHAGUS. Most are acquired but can be congenital.Endoscopy: Procedures of applying ENDOSCOPES for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. transluminal, to examine or perform surgery on the interior parts of the body.Gastroenterology: A subspecialty of internal medicine concerned with the study of the physiology and diseases of the digestive system and related structures (esophagus, liver, gallbladder, and pancreas).Digestive System Diseases: Diseases in any part of the GASTROINTESTINAL TRACT or the accessory organs (LIVER; BILIARY TRACT; PANCREAS).Serial Publications: Publications in any medium issued in successive parts bearing numerical or chronological designations and intended to be continued indefinitely. (ALA Glossary of Library and Information Science, 1983, p203)Pathology, Surgical: A field of anatomical pathology in which living tissue is surgically removed for the purpose of diagnosis and treatment.Unified Medical Language System: A research and development program initiated by the NATIONAL LIBRARY OF MEDICINE to build knowledge sources for the purpose of aiding the development of systems that help health professionals retrieve and integrate biomedical information. The knowledge sources can be used to link disparate information systems to overcome retrieval problems caused by differences in terminology and the scattering of relevant information across many databases. The three knowledge sources are the Metathesaurus, the Semantic Network, and the Specialist Lexicon.ColoradoFundoplication: Mobilization of the lower end of the esophagus and plication of the fundus of the stomach around it (fundic wrapping) in the treatment of GASTROESOPHAGEAL REFLUX that may be associated with various disorders, such as hiatal hernia. (From Dorland, 28th ed)Population Surveillance: Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.Leg Ulcer: Ulceration of the skin and underlying structures of the lower extremity. About 90% of the cases are due to venous insufficiency (VARICOSE ULCER), 5% to arterial disease, and the remaining 5% to other causes.Catheter Ablation: Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.Radio Waves: Electromagnetic waves with frequencies between about 3 kilohertz (very low frequency - VLF) and 300,000 megahertz (extremely high frequency - EHF). They are used in television and radio broadcasting, land and satellite communications systems, radionavigation, radiolocation, and DIATHERMY. The highest frequency radio waves are MICROWAVES.WashingtonElectrocoagulation: Procedures using an electrically heated wire or scalpel to treat hemorrhage (e.g., bleeding ulcers) and to ablate tumors, mucosal lesions, and refractory arrhythmias. It is different from ELECTROSURGERY which is used more for cutting tissue than destroying and in which the patient is part of the electric circuit.Cardiology: The study of the heart, its physiology, and its functions.Sleep Medicine Specialty: A medical specialty concerned with the diagnosis and treatment of SLEEP WAKE DISORDERS and their causes.Emergency Medicine: The branch of medicine concerned with the evaluation and initial treatment of urgent and emergent medical problems, such as those caused by accidents, trauma, sudden illness, poisoning, or disasters. Emergency medical care can be provided at the hospital or at sites outside the medical facility.Endocrinology: A subspecialty of internal medicine concerned with the metabolism, physiology, and disorders of the ENDOCRINE SYSTEM.Nephrology: A subspecialty of internal medicine concerned with the anatomy, physiology, and pathology of the kidney.Neurology: A medical specialty concerned with the study of the structures, functions, and diseases of the nervous system.Catheters, Indwelling: Catheters designed to be left within an organ or passage for an extended period of time.Catheters: A flexible, tubular device that is used to carry fluids into or from a blood vessel, hollow organ, or body cavity.Bile Reflux: Retrograde bile flow. Reflux of bile can be from the duodenum to the stomach (DUODENOGASTRIC REFLUX); to the esophagus (GASTROESOPHAGEAL REFLUX); or to the PANCREAS.Indigo Carmine: Indolesulfonic acid used as a dye in renal function testing for the detection of nitrates and chlorates, and in the testing of milk.Narrow Band Imaging: Imaging techniques that use illumination created with several optical interference filters by which the frequency ranges are spectrally narrowed and light scatter is greatly reduced. Thus the reflected photons reconstituting the images are from distinct depths (the surface and deeper layers) of the object being imaged.Carmine: Coloring matter from the insect Coccus cacti L. It is used in foods, pharmaceuticals, toiletries, etc., as a dye, and also has use as a microscopic stain and biological marker.Quality of Life: A generic concept reflecting concern with the modification and enhancement of life attributes, e.g., physical, political, moral and social environment; the overall condition of a human life.Phototherapy: Treatment of disease by exposure to light, especially by variously concentrated light rays or specific wavelengths.Dihematoporphyrin Ether: The purified component of HEMATOPORPHYRIN DERIVATIVE, it consists of a mixture of oligomeric porphyrins. It is used in photodynamic therapy (HEMATOPORPHYRIN PHOTORADIATION); to treat malignant lesions with visible light and experimentally as an antiviral agent. It is the first drug to be approved in the use of PHOTODYNAMIC THERAPY in the United States.Photochemotherapy: Therapy using oral or topical photosensitizing agents with subsequent exposure to light.Ultraviolet Therapy: The use of ultraviolet electromagnetic radiation in the treatment of disease, usually of the skin. This is the part of the sun's spectrum that causes sunburn and tanning. Ultraviolet A, used in PUVA, is closer to visible light and less damaging than Ultraviolet B, which is ionizing.