Calorimetric studies of the state of water in deeply frozen human monocytes.
Intra- and extracellular phase transitions in human peripheral blood monocyte suspensions with and without the cryoprotectant 1 M dimethylsulfoxide were measured using differential scanning calorimetry. Using an fluorescence diacetate/ethidium bromide assay for membrane integrity and a phagocytosis assay for cell function, it was found that mortality was correlated with several phase transitions under a variety of cooling and warming regimens. As a result of these studies we concluded that: intracellular freezing is lethal, but avoidance of freezing during fast cooling is not sufficient to provide complete protection; a subtle freezing injury in the cryoprotected monocytes can be correlated with a measurable increase in devitrification on warming; and the cell contents form more stable glasses than the Hanks' balanced salt solution with fetal calf serum used as the extracellular medium.
D001834:Body Water / Q000032:analysis; D002152:Calorimetry, Differential Scanning; D002470:Cell Survival; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005615:Freezing; D006801:Humans; D009000:Monocytes / Q000032:analysis* / Q000187:drug effects; D013696:Temperature
D004121:Dimethyl Sulfoxide