title: [Optimization of lyophilization procedures for freeze-drying of human red blood cells].
abstract: OBJECTIVE
  To investigate the different parameters of the lyophilization procedures that affect the recovery of the rehydrated red blood cells (RBCs).
  
  
  METHODS
  Human RBCs loaded in tubes were cooled with 4 different modes and subjected to water bath at 25 degrees celsius;. The morphological changes of the RBCs were observed to assess the degree of vitrification, and the specimens were placed in the freeze-dryer with the temperature set up at 40, -50, -60, -70 and -80 degrees celsius;. The rates of temperature rise of the main and secondary drying in the lyophilization procedures were compared, and the water residue in the specimens was determined.
  
  
  RESULTS
  The protectant did not show ice crystal in the course of freezing and thawing. No significant difference was found in the recovery rate of the rehydrated RBCs freeze-dried at the minimum temperature of -70 degrees celsius; and -80 degrees celsius; (P > 0.05). The E procedure resulted in the maximum recovery of the RBCs (83.14% ± 9.55%) and Hb (85.33% ± 11.42%), showing significant differences from the other groups(P < 0.01 or 0.05). The recovery of the RBCs showed a positive correlation to the water residue in the samples.
  
  
  CONCLUSIONS
  Fast cooling in liquid nitrogen and shelf precooling at -70 degrees celsius; with a moderate rate of temperature rise in lyophylization and a start dry temperature close to the shelf equilibrium temperature produce optimal freeze-drying result of human RBCs.
authors.affiliation: Department of Blood Transfusion, PLA General Hospital, Beijing 100853, China. TMMUChen@hotmail.com
authors.forename: Lin-feng
authors.initials: LF
authors.lastname: Chen
authors.forename: Jing-han
authors.initials: JH
authors.lastname: Liu
authors.forename: De-qing
authors.initials: DQ
authors.lastname: Wang
authors.forename: Xi-lin
authors.initials: XL
authors.lastname: Ouyang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Ji
authors.initials: J
authors.lastname: Che
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: Hui
authors.initials: H
authors.lastname: Li
mesh_terms: D004912:Erythrocytes / Q000166:cytology*; D005612:Freeze Drying; D006801:Humans; D014021:Tissue Preservation / Q000379:methods*