Skin UlcerLeg 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.Pfiesteria piscicida: A dinoflagellate with a life cycle that includes numerous flagellated, amoeboid, and encysted stages. Both the flagellated and amoeboid forms produce toxins which cause open wounds on fish. Pfiesteria piscicida feeds on tissue sloughed from these wounds, as well as on bacteria and algae. It is found in Atlantic estuaries of the United States.Bandages, Hydrocolloid: Dressings comprised of a self-adhesive matrix to which hydrophilic absorbent particles are embedded. The particles consist of CELLULOSE derivatives; calcium ALGINATES; PECTINS; or GELS. The utility is based on providing a moist environment for WOUND HEALING.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Stomach Ulcer: Ulceration of the GASTRIC MUCOSA due to contact with GASTRIC JUICE. It is often associated with HELICOBACTER PYLORI infection or consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).Duodenal Ulcer: A PEPTIC ULCER located in the DUODENUM.Gangrene: Death and putrefaction of tissue usually due to a loss of blood supply.Peptic Ulcer: Ulcer that occurs in the regions of the GASTROINTESTINAL TRACT which come into contact with GASTRIC JUICE containing PEPSIN and GASTRIC ACID. It occurs when there are defects in the MUCOSA barrier. The common forms of peptic ulcers are associated with HELICOBACTER PYLORI and the consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).Protozoan Infections, Animal: Infections with unicellular organisms formerly members of the subkingdom Protozoa. The infections may be experimental or veterinary.Fish Diseases: Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).Wound Healing: Restoration of integrity to traumatized tissue.Pressure Ulcer: An ulceration caused by prolonged pressure on the SKIN and TISSUES when one stays in one position for a long period of time, such as lying in bed. The bony areas of the body are the most frequently affected sites which become ischemic (ISCHEMIA) under sustained and constant pressure.Necrosis: The pathological process occurring in cells that are dying from irreparable injuries. It is caused by the progressive, uncontrolled action of degradative ENZYMES, leading to MITOCHONDRIAL SWELLING, nuclear flocculation, and cell lysis. It is distinct it from APOPTOSIS, which is a normal, regulated cellular process.Peptic Ulcer Hemorrhage: Bleeding from a PEPTIC ULCER that can be located in any segment of the GASTROINTESTINAL TRACT.Peptic Ulcer Perforation: Penetration of a PEPTIC ULCER through the wall of DUODENUM or STOMACH allowing the leakage of luminal contents into the PERITONEAL CAVITY.Skin DiseasesSkin Aging: The process of aging due to changes in the structure and elasticity of the skin over time. It may be a part of physiological aging or it may be due to the effects of ultraviolet radiation, usually through exposure to sunlight.Skin Neoplasms: Tumors or cancer of the SKIN.Buruli Ulcer: A lesion in the skin and subcutaneous tissues due to infections by MYCOBACTERIUM ULCERANS. It was first reported in Uganda, Africa.