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The uptake of polychlorinated biphenyl (PCB) congeners was measured in the larvae of a laboratory-reared chironomid midge, Chironomus tentans, placed in the upper Hudson river, New York during 2 months in 1985. This procedure was investigated as a method for determining water congener concentrations during times of fluctuating PCB levels, and to model uptake of PCBs by river biota. After a 96 h exposure period, total PCB concentrations in the test organisms averaged 6.7 μmgg−1 total PCBs, compared with water concentrations of 67 ng 1−1 (mean value for both months). Uptake and elimination constants, time to equilibrium and concentration factors were calculated for each of 21 selected congeners. Analysis of PCB congeners in insects harvested at intervals during the 96 h period showed that uptake differs with varying degrees of chlorination relative to water concentrations. At the end of the exposure period, concentration factors ranged from 4000 to over 300,000 times the water concentrations. Differences in the replicate indicate potential problems with this method as a field tool; instead of using all congeners separated in analysis, several individual congeners should be selected for use based on their importance to the river fauna and the consistency with which they are analyzed.

A commercially available bacterial colony counter has been modified to allow rapid, accurate, semi-automated evaluation of cell numbers in the micropore filter assay for chemotaxis. The method is valuable for objective, rapid evaluation of cell counts at various levels through the filter, as well as counts on the distal surface of the filter. Coupled with a programmable calculator, this instrument had made feasible a new method of assessing random migration by the regression line analysis, which discriminates between migration rate and mass migration of cells. This combination of equipment may thus serve as a considerable time saving accessory to laboratories engaged in cell locomotion research, but also will allow more rigorous assessment of differences among specific populations of cells.

Polymorphonuclear leukocyte chemotaxis and chemokinesis, in the micropore filter assay, have been evaluated using Regression Line Analysis. The method discriminates between migration rate and the number of migrating cells by statistical comparison of the slope of the regression line and the γ -intercept, respectively. The derivation of this new method of assessment of cell migration is reported. This report also includes critical evaluation of the chemokinesis dose/ response curve and the directional component of chemotaxis. The effect of inhibitors of chemotaxis were evaluated using the new method. Colchicine was found to effect the directional component of chemotaxis, as indicated by decreased rate of locomotion in chemotaxis experiments, and had no effect on random migration and chemokinesis. Cytochalasin B had a general inhibitory effect upon cell locomotion by depressing the rate of random migration and chemotaxis. 1-Tosylamide-2-phenylethyl chloromethylketone (TPCK) had the apparent effect of uncoupling the receptor and effector mechanisms of chemotaxis, or altering the binding of the chemotactic ligand, since random migration was unaffected but the rate of chemotaxis and chemokinesis were depressed. Ionophore A23187 had a generalized inhibitory effect on the cell rate under all three conditions; however, at low concentrations it induced an increase in the number of migrating cells. These studies indicate that the method of regression line analysis is effective in differentiating in vitro the mechanisms of chemotaxis inhibition. The method may be used effectively in the assessment of defective neutrophil chemotaxis in disease states and may prove a useful adjunct to the study of cell locomotory mechanisms.

Fourteen heterosexual inmates who developed acquired immunodeficiency syndrome (AIDS) while incarcerated in New York state prisons were studied. All 14 had regularly used illicit drugs intravenously in New York City prior to imprisonment. Leukocyte counts on admission to the state prison system--when all of these inmates were well--were depressed by one-third when compared with those in matched intravenous drug-using inmates used as controls (mean leukocyte counts, 4,430 vs. 6,320 cells/mm3, respectively; P less than .005); twelve (86%) of the 14 inmates who developed AIDS had counts of less than 5,000 cells/mm3, compared with only six (14%) of the 42 controls (P less than .00001). The 14 inmates developed AIDS symptoms a mean of 22.6 +/- 9.6 months after imprisonment. We conclude that leukopenia is frequently to be found in presymptomatic AIDS infection and that the minimum mean incubation period of AIDS in intravenous-drug abusers is quite prolonged.