Balkan Nephropathy: A form of chronic interstitial nephritis that is endemic to limited areas of BULGARIA, the former YUGOSLAVIA, and ROMANIA. It is characterized by a progressive shrinking of the KIDNEYS that is often associated with uroepithelial tumors.Diabetic Nephropathies: KIDNEY injuries associated with diabetes mellitus and affecting KIDNEY GLOMERULUS; ARTERIOLES; KIDNEY TUBULES; and the interstitium. Clinical signs include persistent PROTEINURIA, from microalbuminuria progressing to ALBUMINURIA of greater than 300 mg/24 h, leading to reduced GLOMERULAR FILTRATION RATE and END-STAGE RENAL DISEASE.AIDS-Associated Nephropathy: Renal syndrome in human immunodeficiency virus-infected patients characterized by nephrotic syndrome, severe proteinuria, focal and segmental glomerulosclerosis with distinctive tubular and interstitial changes, enlarged kidneys, and peculiar tubuloreticular structures. The syndrome is distinct from heroin-associated nephropathy as well as other forms of kidney disease seen in HIV-infected patients.Glomerulonephritis, Membranous: A type of glomerulonephritis that is characterized by the accumulation of immune deposits (COMPLEMENT MEMBRANE ATTACK COMPLEX) on the outer aspect of the GLOMERULAR BASEMENT MEMBRANE. It progresses from subepithelial dense deposits, to basement membrane reaction and eventual thickening of the basement membrane.Kidney Diseases: Pathological processes of the KIDNEY or its component tissues.Proteinuria: The presence of proteins in the urine, an indicator of KIDNEY DISEASES.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Kidney Glomerulus: A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.Albuminuria: The presence of albumin in the urine, an indicator of KIDNEY DISEASES.Podocytes: Highly differentiated epithelial cells of the visceral layer of BOWMAN CAPSULE of the KIDNEY. They are composed of a cell body with major CELL SURFACE EXTENSIONS and secondary fingerlike extensions called pedicels. They enwrap the KIDNEY GLOMERULUS capillaries with their cell surface extensions forming a filtration structure. The pedicels of neighboring podocytes interdigitate with each other leaving between them filtration slits that are bridged by an extracellular structure impermeable to large macromolecules called the slit diaphragm, and provide the last barrier to protein loss in the KIDNEY.