Fundus changes in chronic membranoproliferative glomerulonephritis type II
Dense deposit disease is characterized by the presence of intramembranous dense deposits; their consituents are unknown but immunological and biochemical studies have demonstrated that they contain noγ-globulins or any other plasma protein. In order to clarify the nature of the dense deposits better, we investigated their most distinctive character, (marked electrondensity) by means of ultrastructural histochemistry techniques using thin sections from Formaldehyde fixed, OsO4 postfixed and Epon embedded specimens collected for diagnostic electron microscopy. The dense deposits have a higher osmium affinity than the lamina densa of normal basement membranes, and the electrondensity is strictly osmium-dependent suggesting the presence of a lipid component. Further data, obtained using an extraction method for lipids, seems to confirm out hypothesis.