title: A simple controlled-rate freezing method without a rate-controlled programmed freezer provides optimal conditions for both large-scale and small-scale cryopreservation of umbilical cord blood cells.
abstract: BACKGROUND
  Umbilical cord blood (CB) is being used as a source of alternative HPCs for transplantation with increasing frequency. The goal of CB banks for unrelated transplantation is to provide good quality-controlled CB units that can be transplanted for HPCs into the largest possible number of patients.
  
  
  METHODS
  Large CB samples in freezing bags wrapped with insulators and small samples in cryotubes placed into double styrene-foam boxes were cryopreserved at -85 degrees C without a rate-controlled freezing machine, followed by storage in the liquid phase of nitrogen. After thawing these cells, the viability and recovery of cells, as well as the recovery rate of HPCs such as CD34+ cells, CFU-GM, and total CFU were evaluated.
  
  
  RESULTS
  Measurement of the freezing rate in CB bags and cryotubes demonstrated that this simple method for cryopreservation of CB cells provided optimal conditions for both large-scale and small-scale cryopreservation. Recovery of CB progenitor cells after cryopreservation was also shown to be potentially acceptable when evaluated with CD34+ cells, CFU-GM, and total CFU. These results were comparable to the method using a rate-controlled programmed freezer.
  
  
  CONCLUSIONS
  A simple method for cryopreservation of CB cells without a rate-controlled programmed freezer could provide a sufficient-enough potential for the transplantability of HPCs after thawing.
authors.affiliation: Division of Blood Transfusion, Tohoku University Hospital, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Itoh
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Minegishi
authors.forename: Junko
authors.initials: J
authors.lastname: Fushimi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kudo
authors.forename: Akira
authors.initials: A
authors.lastname: Suzuki
authors.forename: Ayuko
authors.initials: A
authors.lastname: Narita
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sato
authors.forename: Kozo
authors.initials: K
authors.lastname: Akagi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Wada
authors.forename: Akira
authors.initials: A
authors.lastname: Saito
authors.forename: Miwako
authors.initials: M
authors.lastname: Kikuchi
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Okamura
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kaku
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tsuchiya
mesh_terms: D001771:Blood Banks / Q000191:economics; D001793:Blood Preservation / Q000191:economics / Q000379:methods*; D002452:Cell Count; D017046:Cost Savings; D015925:Cryopreservation / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D005312:Fetal Blood / Q000166:cytology*; D005615:Freezing; D006801:Humans; D015203:Reproducibility of Results; D000094902:Blood Banking / Q000379:methods