Abstract: Improved hollow fiber bioreactor systems and cell culture methods are described. The improvement includes means which may be a novel basket bioreactor for extending the extracapillary space of a conventional hollow fiber bioreactor.

Abstract: A unique hollow fiber multiple bioreactor system and method for the propagation of cells and the production of various cell propagation products is described. Simultaneous fluid flow through lumens of hollow fibers in bioreactors is maintained constant across multiple bioreactors so production is maintained essentially constant. The system and method include use of a flow block holder which allows a dissolved oxygen probe to be calibrated at the same pressure as the media in the bioreactor system.

Abstract: A method for preparation of immunoglobulin fragments by specific fragmentation of immunoglobulins, comprising treating a solution of immunoglobulins with a soluble protease so as to achieve substantially complete fragmentation of the immunoglobulins, followed by complexing the protease with a complexing agent (for example, antibody to the protease) to form a protease complex and separating the protease complex from the immunoglobulin fragments. Optionally, the protease (e.g., pepsin or papain) is inactivated prior to formation of the protease complex. In contrast to methods which use immobilized forms of the enzymes, the rate of cleavage and the final yields of F.sub.(ab) and F.sub.(ab')2 fragments are increased substantially.

Abstract: A cartridge includes a male end, a female end and an internal chamber defined by a filter adjacent the male and female ends. The cartridge is specifically designed to be stackable with additional cartridges, as the male end of one cartridge can close the female end of a different cartridge. The cartridges are useful in holding samples for analysis.