Dennis K. Flaherty

PHASE TWO OF AN INTERLABORATORY EVALUATION OF THE QUANTIFICATION OF RAT SPLENIC LYMPHOCYTE SUBTYPES USING IMMUNOFLUORESCENT STAINING AND FLOW CYTOMETRY

In phase one of an interlaboratory study, baseline values for rat splenic lymphocyte populations were established. In phase two, rat splenic lymphocyte populations were evaluated using immunofluorescent staining and flow cytometry following exposure to the immunosuppressive agent cyclophosphamide (CY). The study involved four independent facilities employing a common protocol. All laboratories purchased animals and reagents from the same sources. The objective of phase two was to determine whether each laboratory could detect a significant change in the same splenic lymphocyte population(s) at the same or similar CY dose levels. Crl:CD R BR male rats were dosed by the intraperitoneal route with 1, 3, or 10 mg / kg CY for 4 days. On day 5, spleen cell number and weights were obtained and splenic lymphocytes were evaluated following the lysis of red blood cells with ammonium chloride. Splenic lymphocyte populations were enumerated with monoclonal antibodies using the dual labeling of T-cell subpopulations a...

Evaluation of two instruments for the measurement of aerosols

Abstract The particle size distributions and concentrations of solid and liquid aerosols were simultaneously measured with an Aerodynamic Particle Sizer (APS) and a Phase Doppler Particle Analyzer (PDPA). Three types of aerosols were characterized: mono-sized polystyrene latex (PSL) spheres, mixtures composed of mono-sized PSL spheres, and polydisperse liquid sprays. Good correlation with PSL particle sizes was obtained by both instruments with PSL spheres in the 2–10 μm range. The PDPA had difficulty in the 1 μm and smaller size range, due to the limited resolution and nonlinear behavior of the phase-diameter relationship. For polydisperse liquid sprays, instrument agreement on concentration distributions was consistently good from 1 to about 5 μm diameter. Between 5 and 10 μm, the APS progressively predicted lower concentrations. The divergence between the two instruments may be attributable both to the design of the experimental apparatus and inlet inefficiencies of the APS.

The Effect of Continuous Corticosterone Administration On Lymphocyte Subpopulations in the Peripheral Blood of the Fischer 344 Rat as Determined by Two Color Flow Cytometric Analyses

This study was undertaken to determine the effects of continuous corticosterone administration on lymphocyte subsets in the peripheral blood of Fischer 344 rats. Pellets which released corticosterone over a 21 day period (0.07 mg/day, 0.48 mg/day and 4.8 mg/day) were implanted subcutaneously in male rats. Control rats received pellets containing only the excipient carrier. Rats in the test and control groups were sacrificed at 7, 14 and 21 days. Lymphocyte subsets were enumerated by dual color flow cytometry and the data expressed in absolute numbers/mm3. Effects were observed only in the animals treated with the highest dose which was 70,000 times the normal plasma level. The spleen, thymus and lymph nodes were examined for histopathological changes. At the seven day sacrifice there was a statistically significant decrease in total white blood cells and selective decrements in lymphocytes with reductions in the absolute numbers of the T helper/amplifier, T cytotoxic/suppressor and B cells. Only numbers of natural killer cells were within normal limits. Histopathological data from animals treated with the high dose corticosterone for seven days demonstrated decreased thymic weights and a loss of thymic lymphocytes. At 14 and 21 days, the numbers of lymphocytes returned to the normal range, but the numbers of total T cells remained decreased. Also, thymic weights were reduced but not histological abnormalities were observed in the thymus. The data suggest that corticosterone induced a persistent decrease in total T cells, but only a transient effect on total lymphocytes.

In vitro immunologic studies on a population of workers exposed to phthalic and tetrachlorophthalic anhydride

In vitro radioallergosorbent tests have not been useful in identification of subjects with symptomatic allergic responses to acid anhydrides. By using phthalic anhydride or tetrachlorophthalic anhydride conjugated to human serum albumin, a study was undertaken to determine whether histamine release from basophils or lymphocyte transformation correlated with clinical symptoms, circulating anhydride specific IgE, and skin test reactivity. The data demonstrate that only histamine release from basophils correlated with symptoms and skin test reactivity. We conclude that in vitro histamine assays can be used in the identification of subjects with allergic responses to anhydrides.

The effect of Lasso herbicide on human immune function as measured by in vitro assays.

Using in vitro assays, this study was undertaken to determine whether the components of Lasso herbicide formulation had an effect on the human immune system. Mononuclear cells from human peripheral blood were exposed to analytical alachlor, alachlor conjugated to human serum albumin or Lasso formulation over a concentration range from .01 microM-1.0 microM. The effects of the test materials on the following immunological functions were determined: lymphocyte proliferation induced by mitogen or antigen; antibody synthesis of IgG and IgM isotypes in pokeweed stimulated mononuclear cell cultures; cytotoxic T cell proliferation; lysis of target cells by natural killer cells and lymphokine activated killer cells. The data demonstrated that the test compounds had no significant, dose related effect on the function of immunocompetent cells. Hence, the data suggest that the components of the Lasso formulation have no effect on the human immune system.

A new mask filter cartridge used to determine applicator inhalation exposure to an alachlor herbicide (Lasso®) during normal spraying operations

A filter cartridge with a low air-flow resistance was designed for use on a modified half-face respirator worn during the application of alachlor (Lasso®) herbicide. The filter trapped large concentrations of alachlor while retaining the ability to trap small respirable droplets. Moreover, alachlor could be recovered from the disassembled cartridge and analyzed by conventional methods. The test cartridges were used in combination with conventional personal air samplers to determine whether the filters trapped more alachlor when compared with personal samplers and to determine accurately the amount of alachlor reaching the breathing zone. Farmers sprayed alachlor in the form of alachlor (N = 7) or alachlor mixed with other herbicides or surfactant (N = 15). An average of 4 X 10—2 mg or 2 X 10—4 mg/kg of applied alachlor reached the respirator filters. This concentration was 10-fold higher than the alachlor recovered from the personal samplers. The new filter cartridge is better for determining the amount of alachlor reaching the breathing zone, and there is a low potential for significant inhalation exposure to alachlor during normal spraying operations.

One- and Three-Month Inhalation Studies with Coolanol 25R

AbstractMale and female Sprague-Dawley rats were exposed to an aerosol of COOLANOL 25R dielectric heat transfer fluid (COOLANOL 25R) for 6 hid, 5 d/wk at target-exposure levels of 0, 15, 60, or 120 mg/m3 in a 1-mo study and 0, 1, 5, or 30 mg/m3 in a 3-mo study. In the 1-mo study, high-exposure males and mid- and high-exposure females manifested red perinasal encrustation and discharge during postexposure periods, beginning with wk 2 of the study, but there were no clinical signs of pulmonary impairment, such as altered animal breathing patterns, either during or after COOLANOL 25R exposures. COOLANOL 25R-exposed rats in all exposure groups demonstrated hypertrophy and hyperplasia (predominantly goblet cell) in the most rostra1 respiratory epithelium of the nasal turbinates following histologic examination. With the exception of low-exposure male rats, animals from all other COOLANOL 25R treatment groups demonstrated both macroscopic and microscopic lung lesions. In the 3-mo study, there were no clinical s...