Chloroplasts in Living Cells and the String-of-Grana Concept of Chloroplast Structure Revisited.

In 1980, Wildman et al. (Bot Gaz 141: 24-36) proposed a three-dimensional model for chloroplast structure whereby the grana were arranged in non-overlapping rows, like beads on a string. This string-of-grana model was developed from phase microscope analysis of living cells and partially disrupted, isolated chloroplasts.

Extended leukocyte parameters for hematology analyzers.

Newly introduced, extended leukocyte parameters on laser-based hematology analyzers permit normal samples to be readily identified allowing these samples to be excluded from manual analysis. This enables more hematology laboratory resources to be focused on abnormal specimens. A new reagent that lyses erythrocytes while leaving the optical properties of the leukocytes unaltered is used.

Controls for flow cytometers in hematology and cellular immunology.

The necessity of using freshly prepared biological samples to control and calibrate flow cytometers has impeded the utilization of flow cytometry in the clinical laboratory where regulations demand careful control calibration and yet workload and technician training militate against the preparation of specialized control samples. For a number of years, cell preparations with stabilized properties have been used routinely in hematology laboratories to evaluate the daily performance of automated blood cell counters including optical flow cytometers. Unfortunately, the stabilized preparations do not necessarily duplicate many important aspects of whole blood, resulting in variable performance of a given control preparation on different types of instrumentation.

Automated analysis of reticulocytes using fluorescent staining with both acridine orange and an immunofluorescence technique.

We have used an automated system to measure serial reticulocyte samples from phlebotomized rats and rats treated with the chemotherapeutic agent actinomycin-D. In performing the automated samples, we utilized two different methods. The first method employed a fluorescent dye, acridine orange, which stains RNA in a manner similar to supravital stains presently used in performing reticulocyte counts.