The Lecithin: Cholesterol Acyltransferase Reaction, Lysolecithin and Red Cell Ageing in Blood Stored under Normal Transfusion Service Conditions

Abstract

The lecithin:cholesterol acyltransferase (LCAT) activity and lysolecithin content of human blood stored under standard blood transfusion service conditions at 4 °C for 6 weeks has been investigated. Cooling the blood to 4 °C rapidly inactivates the LCAT reaction, but the enzyme is not denatured during storage under these conditions. Citrate in the anticoagulant did not activate the LCAT reaction in freshly-taken whole blood. The total phospholipid and total lysolecithin content of whole blood decreased during storage at 4 °C for 6 weeks. The lysolecithin content of fresh red cells (2.0-3.0 µmol lysolecithin x 10^-11 per cell) showed no significant change during the storage period.

The how and why of exocytic vesicles

“…They demonstrated that when the intracellular Ca 2+ concentration was increased by treatment with A23187, a bivalent cation ionophore, there was a shape change from discocytes to echinocytes, the 1,2‐diacylglycerol content of the membranes increased, and microvesicles budded from the microvillous‐like projections of the echinocytes. These vesicles were depleted in phosphatidylcholine, spectrin, actin (band 5), and glycophorin, and band 3 and acetylcholinesterase (AChE) were retained 34,58‐61 …”