Abstract: A lysing reagent is employed for stromatolysing the red cells in a blood sample and differentiating the leukocytes into subpopulations. The lysing reagent contains a dodecyltrimethylammonium halide and an aromatic second cationic agent which is either a benzyltrialkylammonium halide or an alkylpyridinium halide. In some methods, the lysing reagent is mixed in the reaction chamber with a major proportion of the diluent, and the blood sample with a minor proportion of the diluent is added to the reaction chamber.

Abstract: A microprocessor-controlled pH and ion concentration meter is disclosed with improved testing procedures. The meter can be tested for excessive internal bias current by measuring the potential (V1) when the meter is connected to a circuit a known voltage (E1) of low impedance and the potential (V2) when the meter is connected to a circuit of the same voltage source (E1) but of known high impedance and having the meter compare (V2-V1) to a preset limit value. The meter can be tested for low internal impedance by further measuring the potential (V4) when the meter is connected to a circuit of a second external voltage (E2) and the known high impedance (R1). The meter then calculates:(V4-V2)and compares that value to preset limits based upon E1, E2 and R1. Such limits can be derived as (Z.sub.o) (E2-E1) / (R.sub.1 +Z.sub.o) where Z.sub.o is the minimum acceptable internal impedance.

Abstract: Compounds of the formula DNB-TZ(P2) (P3) X, wherein TZ is a tetrazolium ring, DNB is 5-(2,4-dinitrophenyl), X is halide and P2 and P3 are each independently halophenyl, nitrophenyl or phenyl. The compound INDT 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-dinitrophenyl) tetrazolium bromide exhibits facile reduction to insoluble chromophoric formazan compared to the chromagen INT. INDT differs structurally from INT 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride by having 2,4-dinitrophenyl instead of phenyl at the 5-position on the tetrazolium ring. The compounds, including INDT, are useful as chromagens for histological staining, as well as in enzyme-amplified staining as a part of immunological or hybridization assays.

Abstract: Aqueous acidic ferrioxalate compositions are disclosed for use as calibrants of pCO2 and of PO2 after photodecomposition. Compositions with high iron(III) to oxalate molar ratios (e.g., 5:1 to 100:1 with 0.3 to 15 millimolar oxalate) produce carbon dioxide on exposure without oxygen consumption. Compositions with low iron(III) to oxalate ratios (e.g., 1:100 to 1:2000) with 0.1 to 5 millimolar iron(III) produce carbon dioxide on exposure with concurrent oxygen consumption. Use of the two types of compositions enables calibration values to be established with varying pCO2 values and with, respectively, high and low pO2 values.

Abstract: Electrodes for the measurement of pCO2 and/or pO2 are calibrated with an exposed aliquot of a calibration liquid. A constituent such as a ferrioxalate salt in the calibration liquid is converted to the gas in a reproducible concentration by exposure of the aliquot to light. In some instances, the calibration liquid is equilibrated with air prior to exposure. Some mechanisms of light generation of carbon dioxide also consume oxygen, so as to depress the pO2 value by a reproducible amount. The use of two different calibration liquids enables both one-point and two-point calibration of the Clark oxygen electrode and the Severinghaus pCO2 electrode of a blood gas instrument.

Abstract: A thin sample on a surface such as a tissue specimen on a microscope slide is exposed to treatment liquid such as a stain, antibody of nucleic acid probe. The treatment is accelerated by exposing the treatment liquid on the surface to infrared radiation. A device is disclosed for placing such slides into a treatment chamber, for example as a plurality of slide pairs held vertically, with treatment liquid held in capillary gaps between each slide pair. An infrared radiation source provides radiation into the treatment chamber to accelerate the treatment of samples on such slide (on one or both surfaces facing each capillary gap) by the treatment liquid.

Abstract: Two rectangular slides having front and rear faces are held with front faces facing each other. Raised end portions on one or both front faces abut and space the front faces by a distance (e.g., 100 to 250 .mu.m) conducive for reversible capillary action between the slides. Raised island portions on one or both front faces are located at corners opposite the raised end portions. The raised island portions serve to maintain spacing between the front faces, particularly as the ends of the slides opposite to the raised end portions contact an absorbent material. An opening between the raised island portions permits liquid to enter and leave the gap between the front faces.

Abstract: A heating and temperature-control device for biological sample containers includes an assembly of lamps emitting infrared radiation within a wavelength of 1-5.5 micrometers and heating said containers by irradiation, and a sensor for infrared radiation of wavelength 7-14 micrometers which picks up the emission from the containers which derives from their heating. The signal obtained from said sensor is used to control the lamp emission in such a manner as to obtain the required container temperature and then keep it constant.

Abstract: A slideholder device contains a handle portion, a rigid thermoplastic body portion and a plurality of metal clip structures. Each clip structure is received within one of the recesses formed along the interior of a sidewall of the body portion. The body portion forms a first combination of aligning elements to hold each clip structure within a recess. The body portion also has elements to directly align slides, especially in the vertical direction. The holder portion can be attached above one or more than one body portion, and can be detachable. The slide assembly includes a plurality of slide pairs, each extending into opposing recesses on opposite sidewalls of a body portion.

Abstract: An electrochemical cell for measuring the activity of one or more ionic species such as pNa, pK, pCa, pNH.sub.4, pCl etc. consisting of two sensors selective to the actual ionic species, one of which is used as the reference electrode and the other as the measurement electrode.The two sensors are chosen preferably identical.The electrode used as the reference electrode is brought into contact with a solution of known ionic activity and an ionic strength which is greater, equal to or substantially greater than that of the unknown solution to be measured.The measurement electrode is brought into contact with the unknown solution to be measured, while a third electrode is used purely for instrumental reasons and does not participate in the measurement.

Abstract: An assay method and kit in which particles bearing a first reagent binding pair member (e.g., anti-digoxin antibody) react with a sample such that analyte binding pair member (e.g., digoxin) binds to the first reagent binding pair member. The reaction mixture is then passed through a filter or membrane or pore size sufficient to allow particles to pass through. A second reagent binding pair member (e.g., digoxin-albumin conjugate) is immobilized on the filter or membrane to trap preferentially either particles which have bound analyte binding pair members or particles which have not, leaving the other class of particles to pass through the filter for detection by resistive pulse techniques, by light absorbence or scattering, by enzymatic read-out (when the particles are enzyme-labeled) or otherwise.

Abstract: In a single-use device for collecting and holding blood samples, provision is made for an evacuated tube with a closure (stopper) that can be pierced by the tip of a needle, the other tip of which is intended to be inserted into a vein of a patient. Disposed below the said pierceable stopper, and in the tube, is a diaphragm intended to passed through by the needle-tip that pierces the stopper, so as to form a supplementar barrier between the interior of the tube and the environment when the pierceable stopper is removed.

Abstract: The present invention provides Gram staining methods and kits in which conventional aqueous iodine-iodide solutions and separate decolorizer solutions are replaced by storage stable alcoholic solutions of iodine-iodide.

Abstract: A microprocessor-controlled pH and ion concentration meter is disclosed with improved calibration and testing procedures. For calibration (standardization), the meter stores number pairs (pX.sub.a, E.sub.a), (pX.sup.b, E.sub.b) where the pX values may be pH values (e.g., 4.00 and 7.00) and the E values are expressed in mV/deg K. When multiple standard values are stored, remeasuring one (e.g., replacing E.sub.a1 by E.sub.a2) can be used to update the others (e.g., E.sub.b1 to E.sub.b2) without remeasurement by applying the formula:E.sub.b2 =E.sub.b1 +(E.sub.a2 -E.sub.a1).Additionally, the meter can be tested for excessive internal bias current by measuring the potential (V1) when the meter is connected to a circuit of low impedance and the potential (V2) when the meter is connected to a circuit of the same voltage source but of known high impedance and having the meter compare (V2-V1) to a preset limit value.

Abstract: A probe polynucleotide binds to a target nucleotide sequence in the nucleic acid of a biological sample, and then is enzymatically extended in the 3'-direction with a mixture of nucleoside triphosphates including at least one nucleoside triphosphate that has been detectably labeled. After separating extended hybrid from unreacted nucleoside triphosphates, detectably-modified nucleotides which have been incorporated are determined. In some forms, the 3'-terminal nucleotide of the probe polynucleotide is selected to form a matched pair with some sample strands, but a mismatched pair with other sample strands. In such cases, if the primer dependent enzyme used for extension is one lacking 3'-exonuclease activity, then only those hybrids forming such a matched pair will be extended and subsequently determined.

Abstract: A holder holding in fixed array:(a) a plurality of vertically-extending slides each having a vertically-extending face,(b) a plurality of vertically-extending cover members, each having a vertically-extending face, each face of a vertically-extending slide being spaced by a first distance less than 0.5 mm from a face of a vertically-extending cover member. The holder engages the vertically-extending slides and vertically-extending cover members adjacent to their upper ends in a fixed array with the sample face of each slide being a first distance from a substantially parallel face of a vertically-extending cover member. The lower edge of each slide extends horizontally and is spaced from a substantially parallel horizontally-extending lower edge of a cover member by the first distance. The space between the horizontally-extending lower edges is open.

Abstract: A device for holding a horizontal array of discrete aliquots of treating liquid having,(a) a horizontally-extending rigid base,(b) a horizontally-extending elastomeric member (or coating) on the horizontally-extending rigid base with a substantially planar horizontally-extending upper surface, and(c) a plurality of recesses formed in the elastomeric member, each recess opening to the horizontally-extending upper surface, the elastomeric member (or coating) having at its upper surface a material sufficiently incompatible with the treating liquid for a discrete aliquot of treating liquid in a recess to form a convex shape extending above the plane of the adjacent upper surface of the elastomeric member (or coating).

Abstract: An RNA signal strand is displaced from a probe strand by a target nucleotide sequence. Without separation, a digestion enzyme selective for displaced RNA, e.g., a polynucleotide phosphorylase, digests the displaced RNA to nucleoside phosphates including ADP. The digestion products are detected, e.g. by phosphorylating the ADP to ATP and detecting the ATP by bioluminescence.

Abstract: An assay method and kit for a hapten such as theophylline employs a first, latex reagent and a second, antibody reagent. By using a monoclonal antibody of the IgA class in the second reagent, interference by patient rheumatoid factor is prevented.

Abstract: A sheetlike object with a planar front face, a linear lower edge, a thickness about 0.5-5 mm and a raised pattern on a portion of the front face about 50-500 micrometers forwardly of the front face. For example, a rectangular microscope slide 25 mm wide, 75 mm high and 1 mm thick coated on one side by an adherent coating 50-500 micrometers thick. Two such slides with abutting coating portions of 50-125 micrometer thickness form a capillary gap between the remainder of the planar surfaces of 100-250 micrometer thickness. One such slide with a coating of 100-250 micrometer thickness forms a corresponding gap when placed against a flat (uncoated) slide. A similar raised portion is created by affixing a thin object (e.g., a 150 micrometer thick cover slip) to a portion of a microscope slide. Liquid is drawn into and out of the capillary gap by contacting the edge of the gap with liquids and then by absorbent.