No abstract

Morphology, crystal structure, and carbon isotopic composition of calcium oxalate from representative species from the family Cactaceae were determined using scannng electron microscopy, x-ray dffraction, and isotope ratio mass spectrometry. Crystals from one species in the Opuntieae tribe of the Cactaceae were druses with acute points composed of the monohydrate form of calcium oxalate (wheweilite). Crystals from three species in the Cereeae tribe were the dihydrate form of calcium oxalate (weddeilte) forming druses made up of tetragonal and isodiametric crystallites. The oxalate was relatively enriced in "'C isotope (-7.3 to -87 %o) compared with woody fibers (-13.3 to -14.1 %o) from the same plants.Most cacti have large amounts of crystalline calcium oxalate distributed throughout their tissues. These deposits are prevalent in crystal idioblasts and the quantity of these cells in a single plant may be related to the amount of Ca available in the soil (7). In the United States large populations of cacti are primarily found in calcareous soils, and thus Ca is not expected to be a limiting factor for crystal idioblast differentiation and subsequent crystal deposition. As oxalate crystallizes, it assumes various morphological aspects. Star-like conglomerates of small crystallites (druses), large single needles (styloids), and bundles of long thin crystals (raphides) Separation of Oxalate Crystals. Crystalliferous regions of Echinomastus, Echinocactus, Escobaria, and Opuntia stems were removed from the plants and allowed to dry in air. The dried material from each species was placed in 12-cm Petri dishes and covered with absolute ethanol. The material was macerated with dissection knives which freed the crystals from their respective cells. Spinach leaves were placed in a glass bowl and covered with water and then macerated with razor blades. The macerates were filtered through four layers of cheesecloth allowing the crystals through, but excluding the plant tissue. About 500 mg of purified oxalate was collected in this manner. These crystals were washed repeatedly with distilled H20 and ethanol until plant debris was no longer evident under a 30x dissecting microscope.Microscopy. Representative crystals from each species were manually placed on a piece of mica (1 x 1 cm) with mounting medium. All specimens were coated with gold-palladium from a distance of 5 cm at a 450 angle. Scanning electron microscopy was carried out with a JSM-2 nning electron microscope (JEOL

Recently, calcium oxalate crystals have been identified in the synovial fluid of patients with arthritis and end-stage renal failure. We describe 4 patients who, during the course of long-term hemodialysis, developed calcium oxalate crystal deposits in the synovium and skin. Clinical manifestations included podagra, tenosynovitis, olecranon bursitis, and acute and chronic synovitis of the large joints that were associated with chondrocalcinosis or subchondral bone erosions. Diffuse involvement of the hand, with chondrocalcinosis of the finger joints, miliary calcified deposits in the skin, and artery calcifications, was observed in 3 patients. The fourth patient had erosive arthropathy. Oxalosis secondary to end-stage renal failure in patients treated with long-term hemodialysis can present with articular man-