Chondrocalcinosis: Presence of calcium salts, especially calcium pyrophosphate, in the cartilaginous structures of one or more joints. When accompanied by attacks of goutlike symptoms, it is called pseudogout. (Dorland, 27th ed)Phosphate Transport Proteins: Membrane proteins that are involved in the active transport of phosphate.Azores: A group of nine islands and several islets belonging to Portugal in the north Atlantic Ocean off the coast of Portugal. The islands are named after the acores, the Portuguese for goshawks, living there in abundance. (Webster's New Geographical Dictionary, 1988, p102 & Room, Brewer's Dictionary of Names, 1992, p42)Calcium Pyrophosphate: An inorganic pyrophosphate which affects calcium metabolism in mammals. Abnormalities in its metabolism occur in some human diseases, notably HYPOPHOSPHATASIA and pseudogout (CHONDROCALCINOSIS).Parenteral Nutrition, Home: The at-home administering of nutrients for assimilation and utilization by a patient who cannot maintain adequate nutrition by enteral feeding alone. Nutrients are administered via a route other than the alimentary canal (e.g., intravenously, subcutaneously).Hyperostosis, Diffuse Idiopathic Skeletal: A disease of elderly men characterized by large osteophytes that bridge vertebrae and ossification of ligaments and tendon insertions.Diphosphates: Inorganic salts of phosphoric acid that contain two phosphate groups.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Metacarpophalangeal Joint: The articulation between a metacarpal bone and a phalanx.Osteoarthritis: A progressive, degenerative joint disease, the most common form of arthritis, especially in older persons. The disease is thought to result not from the aging process but from biochemical changes and biomechanical stresses affecting articular cartilage. In the foreign literature it is often called osteoarthrosis deformans.Wrist Joint: The joint that is formed by the distal end of the RADIUS, the articular disc of the distal radioulnar joint, and the proximal row of CARPAL BONES; (SCAPHOID BONE; LUNATE BONE; triquetral bone).Arthrography: Roentgenography of a joint, usually after injection of either positive or negative contrast medium.Gout: Hereditary metabolic disorder characterized by recurrent acute arthritis, hyperuricemia and deposition of sodium urate in and around the joints, sometimes with formation of uric acid calculi.Hyperparathyroidism: A condition of abnormally elevated output of PARATHYROID HORMONE (or PTH) triggering responses that increase blood CALCIUM. It is characterized by HYPERCALCEMIA and BONE RESORPTION, eventually leading to bone diseases. PRIMARY HYPERPARATHYROIDISM is caused by parathyroid HYPERPLASIA or PARATHYROID NEOPLASMS. SECONDARY HYPERPARATHYROIDISM is increased PTH secretion in response to HYPOCALCEMIA, usually caused by chronic KIDNEY DISEASES.Parathyroidectomy: Excision of one or more of the parathyroid glands.