SYNOPSIS A modified nitroblue tetrazolium test (NBT) is described which is suitable for routine application in the haematology or bacteriology laboratory and which provides a rapid aid to the diagnosis of bacterial infection.Hitherto published methods have recommended the use of heparinized whole blood samples for the performance ofthe NBT test. However, we have demonstrated that the use ofthe sucrose polymer Ficoll permits the test to be carried out on buffy coats prepared from venous blood anticoagulated in sequestrene (EDTA).The mean percentage of NBT-positive neutrophils in 60 healthy control subjects was 6-1. The mean percentage of NBT-positive neutrophils in 56 patients with confirmed or presumed bacterial infection was 34-2. Scores within the normal range were observed in 13 patients in this group.

A b s t r a c tWe evaluated the Sysmex UF-100 urine flow cytometer (TOA Medical Electronics, Kobe, Japan) The development of automated blood cell analyzers has prompted several attempts to produce similar devices for urinalysis. The first commercially available instruments were the Yellow IRIS (International Remote Imaging Systems, Chatsworth, CA) in the United States' and the Sysmex UA series (TOA Medical Electronics, Kobe, Japan) in Japan. 2Demands for a higher level of automation and satisfactory differentiation of specific urine particles have been the driving forces for improvement.We evaluated a second-generation urine flow cytometer, the Sysmex UF-100 (TOA Medical Electronics) by comparing its performance with chamber counting of Sternheimerstained noncentrifuged specimens and with conventional bacterial cultures on cystine-lactose-electrolyte-deficient (CLED) agar plates. Routine reflectometric test strip measurements and morphologic analyses based on the Finnish recommendations 3 were also performed for comparison. The characterization of formed elements with the UF-100 analyzer is based on flow cytometry of particles doublestained for DNA and membranes; particle identification involves measurement of forward-scattered light intensity and fluorescent light intensity, and the widths of these signals. Conductivity of the sample is measured before it enters the flow cell to adjust a constant electrical current in the flow cell for the impedance measurement. The final differentiation is accomplished with multiparametric algorithms (adaptive cluster analysis). A quantitative report is given for RBCs, WBCs, (large) epithelial cells, bacteria, and casts. Additional information flags are provided to indicate the presence of inclusional casts (granular or cellular casts),

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Studies have been made of silica gels modified by chemical reaction of an alcohol or a chlorosilane with the surface hydroxyls of the gel. The over-all objective was correlation of the physical properties of such preparations with their behavior as adsorbents in gassolid and other types of chromatography. The present paper presents the results of the studies of physical characteristics which can be deduced from nitrogen adsorption isotherms. These include surface area, average heats of adsorption, and site energy distribution. In substantially ail cases, surface properties were changed by the chemical modification. The concentration of high-energy adsorption sites was generally reduced, and this resulted in a more uniform surface, superior for chromatography. The average adsorption energy was also reduced.IT IS GENERALLY accepted that exposed hydroxyl groups are present on the surface of a silica gel, distributed somewhat irregularly ; the surface is thus physically and chemically nonuniform. The small radius and acidity of the hydrogen atoms on the surface hydroxyls results in pronounced specific interaction with certain molecules (1-6).There exists a possibility of making a more uniform silica gel surface by substitution of more inert groups for the surface hydroxyls. This substitution should reduce the adsorption of molecules containing either x electrons, OW, or =NH groups. Two substitution reactions of this type have been investigated in the literature. These reactions may be written as:

Summary The Coulter Counter Model S Plus is a 12 parameter haematological analyser designed for service use in haematology laboratories. Eight parameters are standard in current routine haematological practice; the seven parameters generated by the Model S and a platelet count. The method of platelet counting is unique. The remaining parameters are new and comprise the platelet‐crit, the mean platelet volume and size distribution measurements for both platelets and red cells. A description of the instrument is given including differences from the Model S. The new parameters are discussed in detail. Instrument precision is assessed in terms of linearity, reproducibility, drift, carry‐over and protein buildup. The results of all are impressive. Instrument accuracy is assessed in detail; white cell count, red cell count, haemoglobin concentration and mean corpuscular volume being compared with those values measured by the Model S; the Model S Plus haematocrit is compared with the microhaematocrit and platelet counts with those from the Thrombocounter C/Thrombofuge system. All correlations are very satisfactory. Normal values are defined for the new parameters. Instrument design and function are assessed and reagent consumption quoted. Cell control reagents have been evaluated. A realistic hourly throughput for the Model S Plus is 70–80 samples.