Abstract: Novel growth peptides derived from protein factors having molecular weights of about 22 and 45 kDa stimulate mitogenic activity of epithelial, but not fibroblastic cells, in particular, kidney epithelial cells. A source of the factors is scrape-wounded kidney epithelial cells in culture. Synthetic peptides having sixteen amino acids or less, in particular a hexapeptide, YPQGNH (SEQ ID NO: 2) maintain the mitogenic activity. The peptide AQPYPQGNHEASYG (14-Ser) (SEQ ID NO: 15) is effective in reversing acute renal failure in animals. The growth-promoting characteristics of the 22 and 45 kDa proteins and the peptides are useful in treating and diagnosing patients with kidney disease. Nucleotide sequences that encode the factor are useful to develop probes to locate similar factors, to identify genetic disorders involving the factor, and to produce the factor by genetic recombinant methods. The nucleotide sequences and fragments thereof, are also useful for diagnosis and treatment of kidney disorders.

Abstract: An autocrine crystal adhesion inhibitor called CAI is an anionic, sialic acid-containing glycoprotein secreted by kidney epithelial cells that blocks adhesion of calcium oxalate monohydrate (COM) crystals to the cell surface. Novel amino acid sequences are shown for the amino-acid terminus and 6 interval fragments. Persons may be classified according to risk of developing kidney stones, by measuring the amount of CAI in a biological sample. Treatment efficacy is also monitored by this method. CAI is administered in vivo to prevent nephrolithiasis. A rapid, simple assay to detect agents that inhibit adhesion of COM crystals to the surface of kidney epithelial cells is characterized.

Abstract: Autocrine growth factors and isoforms of those factors have been identified, isolated, purified and manipulated. Nucleic acid segments coding for the factors, and antibodies directed to the factors are also aspects of the present invention. The effect of these growth factors on cells is to enhance their growth by increasing mitogenesis. In particular, the growth factors stimulate kidney epithelial cell growth. The growth factors differ from others previously reported in their molecular weights and other properties, for example, resistance to denaturation by dithiothreitol. Methods of preparation and use of the factors are also described. The growth factors are released from kidney epithelial cells by short exposures to a low-sodium environment. The factors have potential for treatment of kidney disease.

Abstract: An autocrine crystal adhesion inhibitor called CAI is an anionic, sialic acid-containing glycoprotein secreted by kidney epithelial cells that blocks adhesion of calcium oxalate monohydrate (COM) crystals to the cell surfaces. Persons may be classified according to risk of developing kidney stones, by measuring the amount of CAI in a biological sample. Treatment efficacy is also monitored by this method. CAI is administered in vivo to prevent nephrolithiasis. A rapid, simple assay to detect agents that inhibit adhesion of COM crystals to the surface of kidney epithelial cells is characterized.

Abstract: Autocrine growth factors and isoforms of those factors have been identified, isolated, purified and manipulated. Nucleic acid segments coding for the factors, and antibodies directed to the factors are also aspects of the present invention. The effect of these growth factors on cells is to enhance their growth by increasing mitogenesis. In particular, the growth factors stimulate kidney epithelial cell growth. The growth factors differ from others previously reported in their molecular weights and other properties, for example, resistance to denaturation by dithiothreitol. Methods of preparation and use of the factors are also described. The growth factors are released from kidney epithelial cells by short exposures to a low-sodium environment. The factors have potential for treatment of kidney disease.

Abstract: A method of producing autocrine growth factors from kidney epithelial cells by lowering the extracellular sodium concentration. The invention also concerns new growth factors, a method of producing the new growth factors, and the medium used to produce these new growth factors.