Glomerular lesions in renal biopsies of Saimiri boliviensis (primate) examined by light and electron microscopy and immunohistochemistry

In order to determine the existence of glomerular lesions in Saimiri bolivi ensis, renal biopsies were performed in 20 clinically healthy animals of si milar age and both sexes. Biopsies were obtained by laparotomy with a Tru-C ut biopsy needle. Mesangioproliferative glomerulonephritis characterized by an increased number of mesangial cells and increased mesangial matrix was present in 35% of the animals. Proliferative glomerulonephritis characteriz ed by increased numbers of epithelial and endothelial cells with narrowed c apillary lumen, and membranous glomerulonephritis characterized by diffuse thickening, wrinkling, and occasional lamellation of basement membranes, we re present in 15% of the samples. Ultrastructural features included increas ed mesangial matrix, fusion of the visceral epithelial foot processes, thic kened glomerular basement membranes, and incipient lamellation. Immunohisto chemical examination revealed granular deposits of immunoglobulin M in the cytoplasm of mesangial cells and in the mesangial matrix in 50% of the samp les.