Abstract: Enzymes are immobilized in a bundle of cellulosic hollow fibres for use as a fibre-bundle dialyzer for purifying blood. Immobilization is carried out by circulating through the lumen of the fibres to activate the fibres an aqueous solution of sodium periodate at a concentration of 0.7-21 mg/ml, a circulation rate of 300-500 mm.sup.3 /minute/mm.sup.2, a temperature of 15.degree.-30.degree. C. and for a period not exceeding 70 minutes, removing excess sodium periodate by washing the fibres, and directly or indirectly anchoring an enzyme to the activated fibres. Washing is preferably carried out by circulating through the lumen of the fibres dionized water followed by a dilute aqueous solution of glycerol. The fibres containing an immobilized enzyme may be sterilized with a sterilizing agent.

Abstract: Dialysis apparatus is provided of the type comprising a casing housing a central cylindrical core which is surrounded by a plurality of layers of capillary tubes constituted by hollow, semi-permeable, fibres. Blood to be treated is caused to flow through the capillary tubes while dialysing solution is passed over the outer surfaces of the tubes. To facilitate the construction of dialysis apparatus with different dialysing surface areas without altering the dimensions of the casing or core, the core is arranged to dismountably carry a plurality of spacing annuli around which the layers of capillary tubes are wound. The diameter of the annuli determines how many layers of capillary tubes can be accommodated in the casing.