Callum Urquhart

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Mononuclear phagocytes isolated from peripheral blood move slowly on albumin-, collagen- and fibronectin-coated glass, as judged by analysis of time-lapse film, although their movement is stimulated somewhat by serum. When a differential-adhesion method is used to purify monocytes from a crude mononuclear cell fraction it appears to select a particularly(More)
Cultured adult chick kidney (CK) cells inoculated with sporozoites of Eimeria tenella showed progressive alterations in their morphological and adhesive characteristics. Scanning electron microscopy (SEM) showed that during a 3-day period following the inoculation of parasites there was a gradual loss of contact between the cells. Initially, the cells(More)
The kinetics of cell aggregation in shaking suspension are complex. Consequently most existing forms of assessment are qualitative or semiquantitative. We have used a Coulter counter coupled to a particle size discriminator to describe aggregation more precisely. BHK21 C13 cells were suspended by light or heavy trypsin/EDTA treatments, and then aggregated(More)
Animals and human infants discriminate numerosities in visual sets. Experiments on visual numerical judgments generally contrast sets in which number varies (e.g., the discrimination between 2 and 3). What is less investigated, however, is set density, or rather, the inter-stimulus distance between the entities being enumerated in a set. In this study, we(More)
When BHK21 fibroblasts adhering to glass were incubated in trypsin they became spherical within a few minutes. They did not, however, respond simultaneously; the most trypsin-resistant cells in an unsynchronized population were of greater length, had more processes projecting from the cell body, and were more spread out than the most trypsin sensitive(More)
The pattern of DNA synthesis in chicken kidney (CK) cells parasitized by Eimeria tenella was altered; a 2-fold increase in the uptake of [3-H]-thymidine occurred in these cells compared with that shown by the controls. This difference was significantly different at 16 h post-inoculation (p.i.) and reached a peak at 20 h p.i. Non-parasitized cells in(More)