Applied Imaging Corporation

Other

Primus Corporation

Alexander M Saunders

Michael A Zarowitz

Patricia J Baldwin

Robert R Berks

Improved single-container, two-phase optical assays for analytes are provided which are faster and require less steps than conventional two phase optical assays. The assays of the invention involve first mixing and incubating an assay mixture including a buffer, solid particles (e.g., agarose beads), an analyte-containing sample, and an affinity agent operable to bind analyte(s) to the solid particles, followed by separation of the mixture into a particle-rich phase and a substantially particle-free phase. In one aspect, the settling step is gravity-induced and is instrumentally monitored to determine when substantially full separation has occurred. Thereafter, the respective phases may be photometrically measured to obtain qualitative and/or quantitative information about the analyte(s). It has been found that measurements taken with only one sensor set before and after settling of the particle-rich fraction give scientifically valid results as a two phase optical assay.

Two-phase optical assay with unitized container and double or single sensor systems

Methods are provided for analyzing DNA of a rare cell in a cell population. In one embodiment, the method involves covering a cell monolayer with a photosensitive material. By illuminating the area over a cell of interest, the material is solidified, permitting manipulation of the underlying cell and/or protection of the cell from DNA-inactivating agents that destroy DNA in other cells in the monolayer. In another embodiment, the monolayer is overlaid with a solid material that becomes soluble when illuminated. By illuminating the area over a cell of interest, that cell can be specifically exposed and DNA from the cell amplified. The methods are particularly useful for analyzing fetal cells found in maternal blood.

Method for analyzing DNA from a rare cell in a cell population

A density gradient medium for the isolation and enrichment of rare cells, including fetal nucleated erythrocytes from a peripheral blood sample is described. The medium comprises a colloidal density gradient medium dispersed in a meltable gel. In one aspect of the invention, the density gradient medium is hypertonic to facilitate separation of maternal red blood cells from fetal blood cells.

Density gradient medium for the separation of cells

A method for isolating and enriching rare cells, including fetal nucleated erythrocytes from a peripheral blood sample is described. The method includes two centrifugation steps, the first a bulk separation step to enrich erythrocytes from other blood components. The second centrifugation comprises a colloidal density gradient medium dispersed in a hypertonic meltable gel. In one aspect of the invention, maternal erythrocytes may be hemolyzed prior to the second density gradient centrifugation to provide additional enrichment for fetal nucleated erythrocytes.

Method for separating rare cells from a population of cells

A centrifuge tube and adaptor apparatus is provided which facilitates separation of biological materials and permits easy extraction of a fraction after centrifugation. The tube is a deformable tube with a wide upper chamber and a narrowed lower portion. The tube is supported within the centrifuge rotor or within another container within the centrifuge by a liquid support medium, which surrounds and supports the narrow portion of the tube, and thus prevents the tube from collapsing during high speed centrifugations.

Centrifuge tube and adaptor

A novel modeling medium comprises a mixture of an organic ductile wax binder and a mica platelet filler which is mechanically worked while the material is in a semisolid state to evenly distribute the mica platelets throughout the mixture. The material exhibits the characteristics of non-ferrous metal with less density than conventional modeling mediums. It provides the bi-color visual characteristic of metal and may be worked at convenient temperatures.

Modeling medium

A historical time series analysis is obtained from a single sample of blood by measurement of hemoglobin and an altered hemoglobin, for example, glycohemoglobin, on a cell-by-cell basis. The results are compared by ratio of glycohemoglobin to hemoglobin on a cell-by-cell basis. Since the alteration of hemoglobin is continuous and irreversible, the ordered set of ratios represents a time-series of the cells, and any deviation from normal will be readily apparent A time-series can also be derived for other constituents, the time-series representing historical data of the other constituents in the person from whom the blood sample was taken.

Growing community of inventors

San Carlos, CA, United States of America

Alexander M Saunders