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W J Armitage

Publications and source records attributed to W J Armitage.

60 records · Page 4Linked to original sources
PubMed1980

The importance of the range of cooling rates within a Nagington and Greaves plug when freezing lymphocytes.

The use of Nagington and Greaves plug for freezing lymphocytes is very straight-forward but the recovery of cells can be low and variable. The survival of lymphocytes was found to be dependent upon the position of the sample within the plug and the plug position in the lipid nitrogen container. Both of these variables affected the rate of cooling of the samples. It is stressed that the range of cooling rates produced by a plug should be determined to ensure that lymphocytes are cooled at suitable rates.

Cell Survival↗
PubMedDate not supplied

Transport of 5-hydroxytryptamine by human platelets incubated in glycerol.

The active transport of 5-hydroxytryptamine was used to assess the effect of glycerol on human platelets. The amine is transported by a membrane-based process that requires energy. The initial rate of uptake was measured using low concentrations of tritium-labeled 5-hydroxytryptamine (0.25 to 2.0 mumol/l) and a short incubation time following exposure of platelets to 0.05 or 1.0 mol/l glycerol at 37 degrees C for 2, 15, or 30 minutes. Control values for Km and Vmax were 0.7 +/- 0.05 mumol/l and 24.0 +/- 1.2 pmol/10(8) cells/10 seconds, respectively. The kinetics of 5-hydroxytryptamine uptake were not affected by incubation of platelets in 0.5 mol/l glycerol. However, 1.0 mol/l glycerol had a time-dependent effect on the uptake process. Initially, 5-hydroxytryptamine transport was noncompetitively inhibited, but this effect was reversed after 15-minute incubation in 1.0 mol/l glycerol. Continued exposure to 1.0 mol/l glycerol, however, increased Km. It was concluded that concentrations of glycerol above 0.5 mol/l might not be suitable as a cryoprotectant for platelet cryopreservation.

Biological Transport, Active↗