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: 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 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: A peristaltic pump for infusing medical solutions to a patient through a flexible tube comprises a pair of counter-rotating drive shafts mounted on a base. A separate roller is eccentrically mounted on each of the drive shafts and each roller has a wheel which is slidingly suspended at its periphery. A pair of curvilinear platens are each separately disposed concentric with a respective drive shaft to engage the tube between the wheel on each roller and the platen. Cooperative counterrotation of the drive shafts cause each roller to sequentially squeeze the tube against its respective platen to create a moving zone of occlusion along the tube.

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 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.