Methods and apparatus for separating red blood cells by density are described. Older red blood cells are more dense than younger ones. Certain changes in the physiology are recorded in changes in hemoglobin or the red blood cells. By assaying different aged red blood cells, one can determine the historical physiological changes over a period of many weeks. Improved separation of red blood cells is accomplished by using rigid capillary tubes having an inner surface which augments the density equilibrium of red blood cells and/or incrementally increasing the centrifugation forces, as well as by chemically treating red blood cells to improve their deformability.
The present application is a continuation in part of application Ser. No. 07/970,840, filed Nov. 3, 1992, and now abandoned, the entire contents of which are hereby incorporated by reference.
It is an object of the present invention to provide a droplet discharging head suited to the discharge of a sample solution, and particularly one that contains a bio-related substance. This object is achieved by a droplet discharging head 1 for discharging a sample solution, wherein the portion of the inner walls of the droplet discharging head 1 that comes into contact with the sample solution is covered with a polymer composed of phosphorylcholine group-containing unsaturated compound units, or a copolymer including same. The droplet discharging head is preferably an electrostatic drive or piezoelectric drive type.
Systems and methods for fractionating components of a sample are disclosed herein. A method of fractionating components of a sample includes establishing a solution density gradient in a capillary channel, applying the sample to the capillary channel, and centrifuging the sample in the capillary channel, thereby separating the components of the sample by density.
A method for separating microorganisms, especially infectious agents, from a mixture by two dimensional centrifugation on the basis of sedimentation rate and isopycnic banding density, for sedimenting such microorganisms through zones of immobilized reagents to which they are resistant, for detecting banded particles by light scatter or fluorescence using nucleic acid specific dyes, and for recovering the banded particles in very small volumes for characterization by mass spectrometry of viral protein subunits and intact viral particles, and by fluorescence flow cytometric determination of both nucleic acid mass and the masses of fragments produced by restriction enzymes. The method is based on the discovery that individual microorganisms, such as bacterial and viral species, are each physically relatively homogeneous, and are distinguishable in their biophysical properties from other biological particles, and from non-biological particles found in nature. The method is useful for distinguishing infections, for identifying known microorganisms, and for discovering and characterizing new microorganisms. The method provides very rapid identification of microorganisms, and hence allows a rational choice of therapy for identified infectious agents. A particularly useful application is in clinical trials of new antibiotics and antivirals, where it is essential to identify at the outset individuals infected with the targeted infectious agent.
A method for separating microorganisms, especially infectious agents, from a mixture by two dimensional centrifugation on the basis of sedimentation rate and isopycnic banding density, for sedimenting such microorganisms through zones of immobilized reagents to which they are resistant, for detecting banded particles by light scatter or fluorescence using nucleic acid specific dyes, and for recovering the banded particles in very small volumes for characterization by mass spectrometry of viral protein subunits and intact viral particles, and by fluorescence flow cytometric determination of both nucleic acid mass and the masses of fragments produced by restriction enzymes. The method is based on the discovery that individual microorganisms, such as bacterial and viral species, are each physically relatively homogeneous, and are distinguishable in their biophysical properties from other biological particles, and from non-biological particles found in nature. The method is useful for distinguishing infections, for identifying known microorganisms, and for discovering and characterizing new microorganisms. The method provides very rapid identification of microorganisms, and hence allows a rational choice of therapy for identified infectious agents. A particularly useful application is in clinical trials of new antibiotics and antivirals, where it is essential to identify at the outset individuals infected with the targeted infectious agent.
