Using communication boards in the field.
Explore the source record for details and available documents.
Communication Devices for People with Disabilities↗
Biomedical subjects
K L Hendricks
Publications and source records attributed to K L Hendricks.
Characterization of factor(s) in culture supernatants affecting cell social behavior.
Treatment of embryonic chick heart fibroblast cultures with 0.2 M urea reversibly increases cellular overlap. The increase in cellular overlapping over that in control cultures may be quantitated by the overlap ratio (R), the ratio of the number of superimposed nuclei observed, to the number expected to occur when cells are assumed to be distributed randomly over the culture substratum (R = observed/expected overlaps). Reversal of the urea-induced increase in R is blocked by 0.2 micrograms/ml cycloheximide. In the presence of cycloheximide, normal (low) overlap ratios are restored to urea-treated cultures by adding non-dialyzable material recovered by washing fibroblast monolayers with serum-free medium. The overlap ratio assay revealed no effect of supernatant material added either to urea-treated cultures in the continued presence of urea, or to untreated cultures. Although unfiltered supernatants were shown by SDS-polyacrylamide gel electrophoresis to contain fibronectin (CSP; LETS; MWappar. = 220,000 d) and smaller proteins, the ability to reverse the urea-induced increase in overlap ratio was present in Diaflo and Millipore filtrates of culture supernatants in which fibronectin was greatly depleted or absent. In contrast, purified fibronectin preparations failed to lower urea-induced increases in overlap-ratio. Partially purified, biologically active supernatants, prepared from 14C-leucine or 125I-labeled cultures, contained several macromolecules smaller than fibronectin that were labeled by both radioisotopes. In particular, one band (MWappar. = 58--60,000 d) was present in polyacrylamide gels of active supernatant and also depleted in gels of homogenates from urea-treated cultures. These results indicate that external macromolecules other than fibronectin are synthesized by cultured fibroblasts and can affect cell social behavior or culture morphology.
Animals↗
Reversible transformation by urea of contact-inhibited fibroblasts.
200 mM urea elicits alterations of cell social behavior in vitro. In the presence of urea, contact inhibition of movement and growth is reduced compared to untreated fibroblastic cell populations. This reduction of contact inhibition is rapidly reversible, but reversal requires some cycloheximide-sensitive cellular process. Cells treated with urea are agglutinable by concanavalin A, suggesting that urea might remove some cell-surface component(s). A nondialyzable factor can, in fact, be detected in the supernatant medium of urea-treated cells. This active constituent appears to be heat-labile and trypsin-sensitive, and can itself restore normal contact-inhibitory behavior to cells maintained in the urea-transformed state by cycloheximide. This system may permit identification and characterization of surface components that are involved in regulating normal cell social behavior.
Agglutination↗