Search PubMed⌕ Search

Biomedical subjects

B J Groves

Publications and source records attributed to B J Groves.

6 recordsLinked to original sources
PubMed1988

Quantitative studies of increased cell-to-substratum adhesion at low temperature.

The cell-to-substratum adhesion of an established epithelial cell line cultured for 24 h on glass coverslips was determined at 4 degrees C, 8 degrees C and 37 degrees C using a miniaturised parallel-plate shearing apparatus. The measurements of the minimum shear necessary to dislodge the cells (minimum distraction force, MDF) demonstrated a three- to fourfold increase in the adhesion of the cells at 4 degrees C (6.17 Pa) compared to that at 37 degrees C (1.36 Pa). At 8 degrees C the MDF was 2.31 pascals. Part of the adhesion was resistant to mild trypsinisation. Trypsin-resistant adhesion (TRA) was stabilised by low temperature, and by treatment with concanavalin A (50 micrograms ml-1) or colchicine (200-400 microM). The effects of con A (140 micrograms ml-1) and low temperature (4 degrees C) were additive, giving a combined MDF of greater than 9.27 pascals. On the basis of their different temperature and protease susceptibility it is suggested that trypsin-sensitive adhesion (TSA) and TRA represent separate functional classes of cell-to-substratum attachment corresponding to 'frictional' and 'tractional' adhesion, respectively.

Animals↗
PubMed1987

A miniaturised parallel-plate shearing apparatus for the measurement of cell adhesion.

The design and construction of a miniaturised shearing apparatus is described. Cultures (24 h) of an established epithelial cell line (BEB) were exposed to flow conditions in the shearing chamber at 37 degrees C, and subsequently glass coverslip cultures were prepared for photography. The critical shear radius (CSR) was determined by densitometry from a negative film and the minimum distraction force (MDF) at the CSR calculated using predetermined viscosity values of the flow medium. The mean calculated MDF of BEB cells ranged from 1.04-1.36 Nm-2, and was independent of the culture inoculation density (9 to 37 X 10(4) cells cm-2) and the time (5-20 min) of exposure to shearing conditions. The MDF was increased to 3.3 Nm-2 by a 30 min exposure of cultures to concanavalin A (50 micrograms ml-1), and this effect was abolished by treating with mannose (0.05 M). The results demonstrated that the radial flow chamber principle is applicable to the measurement of cell to substratum adhesion of cultured mammalian cells.

Animals↗
PubMed1978

Effect of evaporation from sample cups on urea nitrogen assay.

The effects of evaporation from sample cups for urea nitrogen assays were determined. Thirty replicate analyses were performed on each of five groups of pooled human serum subjected to controlled evaporation in our laboratory. We found a mean increase in urea nitrogen concentration of one percent per hour due to evaporation. We urge laboratory personnel to take the action necessary to minimize errors due to evaporation. Specimens should always be capped while awaiting analysis in the laboratory.

Blood Urea Nitrogen↗