Structural changes in sodium urate crystals on heating

Abstract

The mechanism by which crystalline monosodium urate monohydrate (MSU) crystals produce the inflammatory reaction evidenced in acute gouty arthritis is not fully understood. A major step in the pathogenesis of this disease is thought to be crystal-induced lysis of the membrane of the lysosome. Various mechanisms have been proposed for the membranolytic ability of the MSU crystals, but none have clearly defined the molecular or atomic interactions leading to lysosomal membrane lysis (14). It is assumed that both MSU crystals and polymorphonuclear leukocytes must be present ( 5 ) and must come into contact with each other (3), and finally, that the interaction between the crystals and the lysosomal membrane is probably not mechanically mediated (6), but rather based on specific molecular interactions between the atoms in the MSU structure and selected molecular components in the membrane Many of the rheumatology laboratories studying the mechanisms of membranolysis in gout conduct in vitro and in situ experiments using synthetically grown MSU crystals. The various techniques reported for the synthetic preparation of crystalline MSU are very similar. In general, all the methods involve the dissolution of uric acid in an aqueous solution and the adjustment of the pH with sodium hydroxide. Variations in solution temperature for the dissolution of uric acid, and the rate of cooling have yielded crystals that differ in size and (4).

Evaluation of liposome-encapsulated butorphanol tartrate for alleviation of experimentally induced arthritic pain in green-cheeked conures (Pyrrhura molinae)

“…21 Crystals were pipetted in 7-mL aliquots into sterile 2-dram vials. Each dose contained 2 mg of 8% uric acid crystals suspended in sterile saline (0.9% NaCl) solution.…”

Prostaglandin (PG) E2 generation by cultured canine synovial fibroblasts exposed to microcrystals containing calcium.

“…Calcium pyrophosphate dihydrate crystals were synthesised, characterised, and sieved to 10-20 ,uM and heated as described previously.2' Monosodium urate monohydrate crystals were prepared and characterised as described previously.22 They were sonicated to 10-20 FM and then heated to 170°C for 2 h, which does not alter crystal structure. 23 Prostaglandin (PG) E2 assay. This was done by radioimmunoassay by the method of Dunn et al 24 From 0-5 to 3 ml of conditioned medium was extracted for each determination to give the desired sensitivity.…”

Antibodies against crystals

“…MSUM crystals (5 mg) grown according to the method of Mandel (19) were sterilized by UV irradiation for 2 h and suspended in 0.6 ml aliquots of sterile PBS (not containing Mg2 and Ca2), pH = 7.4, saturated with MSUM crystals (saturated solutions were obtained by equilibration of the buffer solutions with the crystal overnight, followed by a centrifugation of 10 mm at 800 g). The suspensions were injected subcutaneously, under sterile conditions, into 3-month-old rabbits.…”