Abstract: Three methods for classifying leukocytes with a flow cytometer by optical measurements on fluorochrome-stained blood cells or those which have been so treated as to provide varying intensity in forward scattered light are useful in the practice of clinical testing. Also included are reagents employed in the practice of such methods.

Abstract: A particle detector for detecting particles of blood components in an electrolyte employs a minute hole through which a fixed quantity of the material is drawn. Electrodes inside and outside the detector pass an electric current through the minute hole. When a particle passes through the hole, it partially blocks the hole, whereby a sharp change is experienced in the amount of current passing through the electrolyte. A syringe fluid path in the detector enters the fluid path for the test fluid at right angles thereto. The inside electrode is disposed in the syringe fluid path near its junction with the fluid path for the test fluid. A colorimeter is placed in series with the flow of the test fluid to measure the concentration of hemoglobin in the test fluid. Automated control of the particle detector is provided by a plurality of cams driving a corresponding plurality of pistons.

Abstract: One particle group in a sample undergoing measurement is demarcated from another particle group in the sample by drawing a discriminant on a plot of a two-dimensional distribution of the particles. To draw the discriminant, the two-dimensional distribution is divided into a grid pattern of a plurality of areas arranged in a number of columns, the number of particles contained in each area is determined, and an area containing the smallest number of particles is selected from a plurality of areas in a specific column. Next, in a column neighboring the specific column, an area containing the smallest number of particles is selected from those areas adjacent the area selected in the specific column. This operation for the neighboring column is thenceforth successively repeated for all subsequent columns to select the area containing the smallest number of particles in each column.

Abstract: Disclosed is a reagent containing auramine O for the fluorescent staining of reticulocytes in a sample of whole blood to permit quantitative determination of the reticulocytes by means of a flow cytometer.

Abstract: A blood sample is prepared by combining a fluorescently tagged monoclonal antibody with blood cells. The sample is then passed through a flow cytometer and light scattered by each blood cell in two directions is sensed simultaneously by a single sensor. Lymphocytes are discriminated from other cells by using an intensity distribution of the total scattered light. Then, by using a distribution of fluorescent light intensity of each cell thus discriminated, the cells in a lymphocyte subclass of interest are enumerated with a high accuracy. The data acquired are utilized in diagnosing immunological incompetence or the like.

Abstract: A reagent for reticulocyte counting by flow cytometry which comprises two solutions, namely, a stock solution for staining in which a dye is dissolved in a nonaqueous solvent, and a buffer solution which satisfies the optimum staining conditions.By combining these two solutions immediately before measurement, a stable final staining solution for reticulocyte counting can always be obtained.

Abstract: A reagent for reticulocyte counting by flow cytometry characterized in that it contains a carbonate salt.If a blood sample is left exposed to ordinary air, non-specific staining of erythrocyte can be prevented with the addition of not less than about 1 mM of NaHCO.sub.3.

Abstract: A method for classifying leukocytes with a flow cytometer by means of optical measurements on fluorochrome-stained blood cells is useful in the practice of clinical testing.

Abstract: A shaking apparatus for agitating and withdrawing a liquid specimen such as blood confined in a sealed vessel, the apparatus including vessel catching hand whereby the vessel is held under the action of a spring and is shaked so as to effect the agitation of the content, and after agitation is finished the content is withdrawn without opening the vessel through needles stabbled through the plug thereof. The needles are cleansed so as not to spoil the specimen contained in the vessel.

Abstract: A method for measuring and analyzing particle size distribution of extremely fine particles, such as blood corpuscles and cells, comprises collecting analyzing particle size distribution from the instrument, setting an estimated distribution theoretically, comparing between the two distributions, determining the difference therebetween, and making the difference a characteristic parameter for the analyzing particle size distribution.

Abstract: A method and apparatus for flow cytometry in which laser light pulses are focused on a sheathed stream, a still picture of cells passing by the region of the focal point is taken by an objective lens-CCD camera combination, the still picture obtained is processed and analyzed to acquire information relating to the shape and internal state of individual cells, and the cells are subjected to analysis based on the information acquired.

Abstract: A reagent for blood analysis comprises, as a lysing reagent for leukocyte count, tetradecyltrimethylammonium bromide and/or hexadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, and citric acid. This reagent is characterized by showing three-peaks fractionation of leukocytes in measuring by means of an automatic blood-analysis instrument. The lysing reagent is used together with a diluent comprising boric acid buffer solution, ethylenediaminetetraacetic acid and (2-pyridylthio-1-oxide) sodium.

Abstract: A reagent for blood analysis comprises, as a lysing reagent for leukocyte count, tetradecyltrimethylammonium bromide and/or hexadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, and citric acid. This reagent is characterized by showing three-peaks fractionation of leukocytes in measuring by means of an automatic blood-analysis instrument. The lysing reagent is used together with a diluent comprising boric acid buffer solution, ethylenediaminetetraacetic acid and (2-pyridylthio-1-oxide) sodium.

Abstract: A shock absorbing mechanism, comprising a slip clutch, is interposed between drive sources and a body carrying optical and dispensing means in an automatic analyzing and measuring apparatus which repeatedly moves and stops said body in a plane to dispense reagents and samples at specified positions in the plane and to optically scan changes in the samples after reacting with the reagents.

Abstract: Disclosed is an analyzing apparatus for applying samples and reagents to the surface of a reaction carrier and for optically analyzing each component contained in the various samples. The dispensing of the samples and reagents and the optical detection operation are performed by an optics/dispensing mechanism moved relative to the reaction carrier in two dimensions. The optics/dispensing mechanism is combined with a cleaning apparatus for cleansing reagents and samples from a dispensing needle by means of a rinsing agent and air ejected toward the needle. The apparatus further includes an automatic lifting mechanism for lifting and replacing a cover disposed on the reaction carrier, and is adapted to move the dispensing needle to a position over a nearby reagent/sample holder so that the needle may take up a desired reagent or sample from the holder and transfer it to the surface of the reaction carrier.

Abstract: A particle size distribution analyzer includes a detector adapted to detect particles by electrical or optical differences from a medium containing the particles in dispersion and generate signals proportionally to the sizes of the detected particles, a threshold circuit adapted to remove noises or fragmental signals from the detected signals so as to obtain pulse widths at a constant position, a gate circuit adapted to decide the passage or non-passage of the particles through the threshold circuit, a counter circuit adapted to count the number of the particles fed from the gate circuit, a memory connected to the counter circuit, an arithmetic circuit connected to the memory and the detector, a controller circuit connected to the gate circuit, the memory and the counter circuit, and means for displaying or recording the data stored in the memory.

Abstract: A particle size distribution analyzer comprising a particle detector adapted to produce signals in response to the sizes of particles by electrical or optical differences between a liquid and the particles dispersed therein, a plurality of comparators connected in parallel to said particle detector for producing pulses in correspondence with said signals, counters connected to each of said comparators for counting said pulses, a data input/output unit connected to each individual counter, whereby said input/output circuit receives signals sent in parallel from said counters, a keyboard unit connected to said input/output circuit operative to enable various conditions to be input from the outside, a central processing unit circuit, a read only memory and, a random access memory connected to said later input/output unit for statistically processing the pulse received, and a data output unit connected to said data input/output unit, said data output unit including at least a recorder.

Abstract: The leg of a tray constituting an electrophoretic cell and accommodating a gel layer are provided with a centrally located partitioning member to eliminate uneven current density over the entire gel layer when the cell is energized during electrophoresis.

Abstract: Precise counting of blood platelets is achieved by discriminating electrical pulse signals derived from blood platelets suspended in a diluted blood sample from electrical pulsive signals derived from red blood cells also suspended in the sample and correcting the count of platelets on the basis of a correction formula that uses the electrical pulsive signal derived from red blood cells as a correction parameter.

Abstract: A fully automatic system is disclosed for determining the seven blood parameters, red blood counts (RBC), hematocrit (HCT), white blood counts (WBC), mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). The blood sample collected is divided into two solutions, one for use in red blood counts and subjected to the colorimetric analysis for HGB determination and the other for use in white cell counts. A portion of the RBC solution is subjected to the double blood dilution and it enters a red cell counting portion. The peak value of electrical pulses supplied by said counting portion is indicative of the hematocrit. These data are used by preset arithmetic circuits to determine MCH, MCV and MCHC. White blood corpuscles are counted by a counting means of the same structure as that of the red cell counting portion.