Reference

The effect of sodium chondroitin sulfate and/or simple salt on the dispersity of kaolinite in concentrated suspension

The effect of sodium chondroitin sulfate and/or simple salt on the dispersity of kaolinite in concentrated suspension. Shimabayashi, Saburo; Nakagaki, Masayuki (Fac. Pharm. Sci., Kyoto Univ., Kyoto, Japan). Yakugaku Zasshi, 98(6), 782-8 (Japanese) 1978. CODEN: YKKZAJ. ISSN: 0031-6903. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) Sedimentation vol. (V2/V1), yield value (F), and differential viscosity (df/dg), obtained from the flow curve, were studied by changing the concn. of Na chondroitin sulfate (I) [9082-07-9] and (or) salt in a concd. system of aq. kaolinite suspension. The above parameters decreased with increasing concn. of I or salt by breaking the card-house structure of kaolinite, but these parameters increased at high concn. of salt, showing aggregation between faces and (or) edges of kaolinite by electrostatic shielding effect of the added salt. On the other hand, relative viscosity decreased with the concn. of salt or I because the hydrodynamic radius of secondary particles became smaller with the concn. of addend, and the structure of secondary particles was more compact than card-house structure at high concns. of the salt. The mean diam. of secondary particles, measured by the sedimentation balance in a dil. suspension, also decreased with the concn. of addend, as did F, df/dg, and V2/V1. The dispersing effect corresponds to making small particles in dil. suspension and to breaking the card-house structure in the concd. suspension. The effective dispersing concn. of I increased with the concn. of kaolinite because a dispersing effect appears owing to its adsorption onto kaolinite but, in the case of the salt, the concn. dependence was small because the ionic strength of the medium is effective for dispersing kaolinite particles by shielding the electrostatic attractive force between the face and edge of kaolinite particles.

Interaction between human leukocyte elastase and chondroitin sulfate

Interaction between human leukocyte elastase and chondroitin sulfate. Baici, Antonio; Bradamante, Paola (Dep. Rheumatol., Univ. Hosp., Zurich CH-8091, Switz.). Chem.-Biol. Interact., 51(1), 1-11 (English) 1984. CODEN: CBINA8. ISSN: 0009-2797. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Structum (chondroitin sulfate) [9082-07-9] interacts with human leukocyte elastase [9004-06-2], a potent mediator of articular cartilage degrdn., producing a partial inhibition of the enzyme activity (60% at satn.). Kinetically, the inhibition mechanism can be classified as simple intersecting, hyperbolic noncompetitive and is almost identical to that found earlier for similar compds. The best inhibitory activity of chondroitin sulfate was found in fractions having at the same time a high proportion of chondroitin-6-sulfate relative to the corresponding 4-isomer and a high mol. mass. Thus, a fraction with high Mr and contg. 92% 6-sulfate inhibited leukocyte elastase with K2 = 1.8 mg/mL, whereas a fraction with low Mr and almost equal compn. of the 4- and 6-isomers had Ki = 140 mg/mL. Ki for unfractionated chondroitin sulfate was 3.4 mg/mL. It is suggested, that the modulation of the extracellular activity of cartilage-derived factors may explain, at least in part, the beneficial effects of some therapeutically used chondroprotective agents.