What is new about crystals other than monosodium urate?

Recently, attention has focused on the effects of weather conditions and se asonal changes on the incidence of acute microcrystalline events. Acute gou t attacks are more frequent during the spring, but seasonal variations in t he incidence of acute pseudogout attacks are less clearly defined. Genetic analysis of two unrelated families with calcium pyrophosphate dihydrate (CP PD) crystal deposition disease showed linkage to the short arm of chromosom e 5p. Several recent reports show CPPD crystal disease occurring in associa tion with Gitelman syndrome, the hypocalciuric-hypomagnesemic variant of Ba rtter syndrome. Two signaling pathways, protein kinase C and adenyl cyclase , modulate generation of extracellular pyrophosphate by porcine cartilage c hrondrocytes. These transduction mechanisms may provide potential targets f or the treatment of CPPD crystal deposition disease. A controlled clinical trial showed ultrasound therapy to be beneficial in the treatment of sympto matic chronic calcific tendinitis of the shoulder, There is evidence that a patite crystals may contribute to cartilage damage in osteoarthritis and th at therapeutic interventions to prevent the formation and biologic effects of the crystals may potentially retard the progression of the osteoarthriti c process. Curr Opin Rheumatol 2000 12:228-234 (C) 2000 Lippincott Williams & Wilkins, Inc.