Abstract: A single needle system for withdrawing donated blood, processing the blood to harvest components such as platelets, and returning processed blood to the donor through the single needle. Processing is performed by a centrifuge which separates blood components into stratified layers with a buffy coat containing platelets and white blood cells stably interfacing a red blood cell layer. Blood is withdrawn during a draw cycle and returned to the donor during a return cycle. A recirculation system is provided so that blood flows at a reduced rate through the processing system during the return cycle in order to minimize return cycle time while maintaining the stable position of the interface between buffy coat and red blood cell layers. A storage bag receives processed blood during the draw cycle and blood is squeezed from the bag during the return cycle, a portion returned to the donor and another portion entering the recirculation path.

Abstract: A method and apparatus for determining, controlling or establishing the level of a constituent such as anticoagulant in a body fluid such as blood in a procedure for processing the fluid. The anticoagulant flow rate from an anticoagulant reservoir, the blood flow rate, the flow rate of collected fluid and the flow rate of replacement fluid are monitored, and an anticoagulant flow balance is established whereby the flow of anticoagulant into the donor or patient will be equal to the flow rate of anticoagulant out of the anticoagulant reservoir, plus the flow rate of anticoagulant from the donor or patient, plus the flow rate of anticoagulant in the replacement fluid, minus the flow rate of anticoagulant in the collect fluid. The flow rate of anticoagulant from the donor or patient can be determined based on the anticoagulant metabolic half-life, the volume of the donor's or patient's blood, and the amount and time of infusion of anticoagulant into the donor or patient.

Abstract: A method and apparatus to concentrate and purify islets of Langerhans from a tissue suspension containing islets and tissue fragments. The tissue suspension is flowed through an inclined channel such that laminar flow is established in the channel. The islets settle toward the channel bottom and are drawn out of the channel through an outlet in the channel bottom, while the remaining tissue suspension flows out a second outlet positioned higher than the islet outlet. Additional concentration or purification may be accomplished by passing the islets through the channel additional times and by centrifuging or filtering operations.

Abstract: Centrifuge drive apparatus including a support including a plurality of resilient mounting members that are spaced around a rotation axis and are intersected by a mounting plane that is perpendicular to the rotation axis, and a centrifuge bowl and drive motor assembly having a combined center of gravity in the vicinity of the mounting plane to reduce vibration.

Abstract: A heat exchanger useful for example in medical applications has a plurality of parallel abutting channels separated by a sheet through which heat is exchanged, with the channel-defining walls preferably in line contact with the sheet and with sharp changes in direction rendering a generally serpentine flow pattern in each channel.