Abstract: This invention is directed to means for inhibiting the apparent shift in the buoyant density of and/or to restore any loss in the buoyant density of the granulocytic white blood cells in a sample of blood, thereby insuring the quality of the separation of lymphocytes and monocytes from granulocytes in a blood sample. The invention comprises contacting a blood sample with a hypertonic fluid containing a low molecular weight organic or inorganic ionic substance and/or with an isotonic or hypertonic fluid containing a high molecular weight organic substance which may contain organic molecules having a lipophilic substituent in their structures and/or with a culture medium for blood cells. An integral part of the invention is an improved blood separation tube utilizing a gel-like substance having a specific gravity between 1.060-1.065 g/cm.sup.3 to significantly enhance the purity of cell separation, while providing acceptable cell yields.

Abstract: This invention is directed to means for inhibiting the apparent shift in the buoyant density of and/or to restore any loss in the buoyant density of the granulocytic white blood cells in a sample of blood, thereby insuring the quality of the separation of lymphocytes and monocytes from granulocytes in a blood sample. The invention comprises contacting a blood sample with a hypertonic fluid containing a low molecular weight organic or inorganic ionic substance and/or with an isotonic or hypertonic fluid containing a high molecular weight organic substance which may contain organic molecules having a lipophilic substituent in their structures and/or with a culture medium for blood cells. An integral part of the invention is an improved blood separation tube utilizing a gel-like substance having a specific gravity between 1.060-1.065 g/cm.sup.3 to significantly enhance the purity of cell separation, while providing acceptable cell yields.

Abstract: The rheological properties of thixotropic, gel-like compositions employed in blood separation tubes are controlled by incorporating in the composition up to about five percent by weight, based on the amount of composition, of a disilazane.

Abstract: This invention relates to a method for isolating platelets, lymphocytes, and monocytes from anticoagulated blood. The method involves centrifuging at high force a sample of uncoagulated blood with a water-insoluble thixotropic gel-like material having a specific gravity between 1.065-1.077 g/cc for a length of time sufficient to cause the gel-like material to form a barrier between the platelets, lymphocytes, monocytes, and plasma fraction of the blood and the heavier blood cells. Thereafter, the plasma is withdrawn and the platelets, lymphocytes, and monocytes removed from above the barrier in a buffer solution. Where desired, the platelets can be separated from the lymphocytes and monocytes utilizing a similar process but wherein the water-insoluble thixotropic gel-like material has a specific gravity of less than about 1.055 g/cc.

Abstract: Methods and apparatus for separating blood which utilize suspendable contact-activating particles to initiate blood clotting generally throughout the volume of blood are disclosed herein. The contact-activating particles are deposited in a vessel; and when whole blood is supplied to the vessel, the particles are suspended throughout the volume of the blood and remain so suspended, without mechanical agitation, during at least the initial stages of coagulation. The particles are precipitated from the serum portion of the blood during a subsequent centrifugal separation. Also, a process for making appropriately sized contact-activating particles is disclosed.

Abstract: Gel-like composition useful for separating and partitioning whole blood into serum and clot portions. The composition has a specific gravity between that of the serum and clot portions such that, when centrifuged in the presence of whole blood, the composition forms a chemical and physical barrier between the serum and clot portions. The composition comprises, in combination, a silicone fluid, an inert siliceous filler dispersed therein, and a network former consisting of a polysiloxane-polyoxyalkyl copolymer which stabilizes the composition by minimizing and/or avoiding "wet out" of the siliceous filler with time. The composition has a viscosity within the range of about 200,000 to about 600,000 centistokes, preferably within the range of about 350,000 to about 450,000 centistokes.

Abstract: Gel-like composition useful for separating and partitioning whole blood into serum and clot portions. The composition has a specific gravity between that of the serum and clot portions such that, when centrifuged in the presence of whole blood, the composition forms a chemical and physical barrier between the serum and clot portions. The composition comprises, in combination, a silicone fluid, an inert siliceous filler dispersed therein, and a network former consisting of a polysiloxane-polyoxyalkyl copolymer which stabilizes the composition by minimizing and/or avoiding "wet out" of the siliceous filler with time. The composition has a viscosity within the range of about 200,000 to about 600,000 centistokes, preferably within the range of about 350,000 to about 450,000 centistokes.

Abstract: In apparatus for effecting a sealed separation or partition between two phases of a multiphase liquid upon centrifugation of the multiphase liquid, a device which facilitates access through the partition to a phase of a separated multiphase liquid which is confined between the partition and a lower or closed end of a vessel retaining such liquid.

Abstract: Gel-like compositions useful for separating and partitioning whole blood into serum and clot portions. The composition comprises a polybutene liquid polymer having an inert high surface area inorganic filler dispersed therein, the filler being present in an amount sufficient to impart to the composition a specific gravity ranging from about 1.030 to about 1.090 and a viscosity ranging from about 200,000 to about 850,000 centistokes. When centrifuged in the presence of whole blood, the composition forms a chemical and physical barrier between the serum and clot portions.