title: Behavior of ordered sodium in enzymatically depleted cartilage tissue.
abstract: The onset of cartilage tissue disorders can be characterized by a loss of proteoglycans (PGs) and diagnosed by contrast-enhanced proton ((1)H) MRI techniques, as well as sodium MRI. The behavior of sodium located in anisotropic environments, is examined as a function of cartilage degeneration. PGs are proteolytically depleted from the cartilage samples, which gives rise to a decrease of the ordered sodium content. More surprisingly, however, the residual quadrupolar couplings are shown to increase with increasing depletion levels. Since the residual quadrupolar couplings are intimately related to local order and anisotropic motion, measuring their distribution in cartilage may provide insight into the structural changes that occur within the tissue upon degradation. In this study relatively mild orientational dependence of the couplings was found. Little or no free sodium was observed in the cartilage specimens under study.
authors.affiliation: Chemistry Department, New York University, New York, New York, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Ling
authors.forename: Ravinder R
authors.initials: RR
authors.lastname: Regatte
authors.forename: Mark E
authors.initials: ME
authors.lastname: Schweitzer
authors.forename: Alexej
authors.initials: A
authors.lastname: Jerschow
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000737:chemistry*; D002417:Cattle; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012964:Sodium / Q000032:analysis*; D014357:Trypsin / Q000737:chemistry*
chemical_list: D012964:Sodium; D014357:Trypsin