Document Detail


Metabolism of rabbit angiostatin glycoforms I and II in rabbits: angiostatin-I leaves the intravascular space faster and appears to have greater anti-angiogenic activity than angiostatin-II.
MedLine Citation:
PMID:  11477374     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Plasminogen (PLG) exists in the circulation as two glycoforms, I and II. Angiostatin (AST) is a polypeptide that has been cleaved from the kringle region of PLG and has strong anti-angiogenic properties. AST-I and AST-II, which consisted only of kringles 1 through 3, were prepared by the action of urokinase on purified rabbit PLG-I and PLG-II, respectively, in the presence of N-acetyl cysteine, followed by affinity chromatography on lysine-Sepharose. Purified AST-I and AST-II were tested for functional activity with a chick chorioallantoic membrane (CAM) model; when similar amounts were applied to a 6-day CAM, AST-I was substantially more effective than AST-II in decreasing vascular supply to the CAM over a 72-hour period; this activity correlated with a loss of capillaries, probably through apoptosis of endothelial cells. Radiolabeled AST-I and AST-II (iodine 125 and iodine 131) were co-injected intravenously into healthy rabbits to determine their clearances from plasma measured over 3 days. Over a dose range of 0.08 to 2.7 microg/kg, the fractional catabolic rate within the intravascular space (j(3)) indicated that AST-I was cleared 3-fold to 4-fold more rapidly than AST-II (P < .001). The catabolic half-life of AST-I (2.01 +/- 0.19 days) was significantly less than that of AST-II (2.62 +/- 0.20 days). The faster clearance of AST-I from the intravascular space was matched by its more rapid passage than AST-II to the extravascular space of various organs over 60 minutes in vivo. This property of AST-I as compared with AST-II may partially explain its greater anti-angiogenic potential. From the plasma concentrations of PLG-I and PLG-II and their relative behaviors toward rabbit VX-2 lung tumors in vivo, we predict that substantially greater quantities of AST-II than AST-I may be released into the extravascular space of tumors.
Authors:
M W Hatton; S Day; S M Southward; M Dereske; B Ross; E Seidlitz; G Singh; M Richardson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of laboratory and clinical medicine     Volume:  138     ISSN:  0022-2143     ISO Abbreviation:  J. Lab. Clin. Med.     Publication Date:  2001 Aug 
Date Detail:
Created Date:  2001-07-30     Completed Date:  2001-08-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375375     Medline TA:  J Lab Clin Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  83-93     Citation Subset:  AIM; IM    
Affiliation:
Department of Pathology and Molecular Medicine, McMaster University Health Sciences Centre, and the Hamilton Regional Cancer Centre, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Angiostatins
Animals
Capillaries / metabolism
Chick Embryo
Endothelium, Vascular / metabolism
Iodine Radioisotopes / diagnostic use
Isomerism
Neovascularization, Physiologic / drug effects*
Peptide Fragments / chemistry,  isolation & purification,  pharmacokinetics*
Plasminogen / chemistry,  isolation & purification,  pharmacokinetics*
Rabbits
Species Specificity
Tarsal Joints / metabolism
Chemical
Reg. No./Substance:
0/Iodine Radioisotopes; 0/Peptide Fragments; 86090-08-6/Angiostatins; 9001-91-6/Plasminogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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