Abstract: Polypeptides of pigment epithelium derived factor (PEDF) isolated from human plasma and fragments thereof, methods for preparing them, pharmaceutical compositions containing them and methods for diagnosis and treatment of angiogenesis-related diseases using such polypeptides.

Abstract: The invention relates to synthetic peptides derived from the K.sup.348 -A.sup.380 (8-40 of SEQ ID NO:1) sequence of the vitronectin molecule. The peptides modulate the biological activities of plasminogen activator inhibitor-1 (PAI-1) and are useful as active ingredients of pharmaceutical compositions for the treatment of disorders such as bleeding disorders, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, disseminated intravascular coagulation, tumor cell invasion and metastasis, inflammation, liver diseases, bacterial blood infections, pregnancy toxicosis, and pathological conditions associated with the control of angiogenesis, or with nerve regeneration, or with excessive tPA-mediated proteolysis.

Abstract: There is provided a kit or reagent for assaying the cellular integrity (intactness) of blood platelets comprising means for determining the quantity of PKA released by a number of platelets into a certain volume of plasma. The assay is based on determining cAMP-dependent phosphorylation of vitronectin (protein S) in plasma using radioactively labelled [.gamma..sup.32 P]ATP as phosphate donor. The assay can be based on the specific inhibition of the phosphorylation in blood fluid by protein kinase inhibitors. The invention further relates to pharmaceutical compositions for the treatment of pathological conditions associated with impaired platelet function in humans, which comprises administering to a person in need thereof a physiologically active quantity of a PKA inhibitor adapted to decrease or prevent vitronectin phosphorylation. The inhibitor can be synthetic or genetically engineered peptide.