SUBCLINICAL RENAL OXALOSIS IN WILD-CAUGHT JAPANESE MACAQUES (MACACA-FUSCATA)

Various degrees of crystal deposition were found in the kidneys of 12 out of 59 Japanese macaques (Macaca fuscata) caught in the wild in Gif u, Japan. The needle- or rod-shaped crystals, which were radially arra nged and occurred in the lumen and epithelium of the renal (mainly the proximal) tubules, were birefringent under polarized light. They stai ned with alizarin red S at a pH of 7.0 but not 4.2, and were identifie d as calcium oxalate. The morphological features of the renal lesions were similar to those previously reported in oxalate poisoning, and it was believed that the macaques ingested the oxalate in plants.