β2-Microglobulin has been implicated in haemodialysis-associated amyloidosis. Although β2-microglobulin is removed ineffectively by diffusion alone, it can be removed effectively by either filtration or adsorption. This study elucidates the characteristics of the adsorption of β2-microglobulin on various hollow fibre dialysis membranes. β2-Microglobulin labelled with radioisotope125I was added to the serum of haemodialysis (HD) patients so that the weight ratio of non-labelled to labelled β2-microglobulin was in the range 1000:1 - 500:1, with the concentration of the latter accounting for approximately 0.01 Ci m-3. Hollow fibre membranes of 2 mm in length (100 - 500 ml-1of serum) made of poly(methyl methacrylate) (PMMA) (BK-1.0P, TK-111-B, HF-200 and B2-100, polyacrylonitrile (PAN) (PAN-50P) and regenerated cellulose (TAF 10) were placed in the test solution and agitated for a predetermined time. The hollow fibre membranes were then rinsed with saline, and their radioactivity was measured to determine the amount of β2microglobulin adsorbed. The B2-100 PMMA membranes can compete in terms of adsorption capacity with the other PMMA membranes. The time taken to reach adsorption equilibrium was only 30 min for PAN-50P, 2 - 9 h for BK-1. OP, TK-111-B and HF-200 and approximately 100 h for B2-100. The adsorption capacity of the PAN membranes was an order of magnitude lower than that of the PMMA membranes, and cellulosic membranes adsorbed β2- microglobulin only slightly. From the adsorption capacity data, it was calculated that the β2-microglobulin concentrations of a typical HD patient (extracellular volume, 11.7l) decreased from 45 to 33.9 mg l-1(amount removed, 130 mg) for HF-200 (2.01 m2) and from 45 to 44.6 mg l-1(amount removed, 4 mg) for PAN-50P (0.5 m2) due to adsorption alone during conventional HD treatment. The experimental results indicate that PMMA membranes adsorb reasonable amounts of β2-microglobulin, but at markedly different rates. © 1989.
Gelfand, M. J., Nishii, L. H., & Raver, J. L. (2006). On the nature and importance of cultural tightness-looseness. Journal of Applied Psychology, 91(6), 1225–1244. https://doi.org/10.1037/0021-9010.91.6.1225