Retention of Coagulation Factors and Storage of Freeze-Dried Plasma.

INTRODUCTION: Terumo BCT is developing a system to produce a freeze-dried plasma product, Terumo's freeze-dried plasma (TFDP), that is stored in a rugged, light-weight plastic package suitable for field use, which retains a stable level of specific coagulation factors and proteins within clinical range, when stored for up to 2 years at room temperature and 4°C. MATERIALS AND METHODS: Plasma frozen within 24 hours of phlebotomy (PF24) were thawed, sampled, and individually lyophilized to produce a corresponding TFDP unit. Fresh frozen plasma (FFP) units were thawed, sampled, pooled in groups of 10 units (also sampled) and lyophilized to produce 2 lots of TFDP. Each TFDP unit was reconstituted with water for injection (WFI) and tested for pH, prothrombin time, activated partial thromboplastin time, factors V and VIII, fibrinogen, protein C, and protein S. Results were compared with PF24/FFP. Additional FFP units were thawed, sampled, pooled, divided to generate 2 TFDP units for each time point (1, 2, 3, 6, 12, 18, and 24 months, one each stored at 4°C and 25°C) and lyophilized. Postlyophilization, TFDP units were stored at 4°C or 25°C, reconstituted with WFI, and tested for the factors listed above. Residual moisture content of the lyophilized plasma was also tested. RESULTS: Coagulation factor activity of TFDP was ±20% of PF24/FFP. Pooling standardized variation in TFDP coagulation factor activities, which were within clinical ranges postlyophilization. The pH of TFDP and PF24/FFP were within required range. Residual moisture content of TFDP was <2%. CONCLUSIONS: The TFDP process had no negative impact on coagulation factor activity. Input plasma and anticoagulant type did not affect TFDP quality. Pooling FFP normalized factor variability in TFDP and did not negatively impact product quality. The TFDP is stable for up to 24 months at room and refrigerated temperatures. Terumo's freeze-dried plasma is comparable to PF24/FFP. It does not require complex logistics or time-consuming thawing. Terumo's freeze-dried plasma may be suitable for rapid treatment of coagulopathies with logistical advantages over PF24/FFP.

Zar1 represses translation in Xenopus oocytes and binds to the TCS in maternal mRNAs with different characteristics than Zar2.

Maternal mRNAs are translationally regulated during early development. Zar1 and its closely related homolog, Zar2, are both crucial in early development. Xenopus laevis Zygote arrest 2 (Zar2) binds to the Translational Control Sequence (TCS) in maternal mRNAs and regulates translation. The molecular mechanism of Zar1 has not been described. Here we report similarities and differences between Xenopus Zar1 and Zar2. Analysis of Zar sequences in vertebrates revealed two Zar family members with conserved, characteristic amino acid differences in the C-terminal domain. The presence of only two vertebrate Zar proteins was supported by analyzing Zar1 synteny. We propose that the criteria for naming Zar sequences are based on the characteristic amino acids and the chromosomal context. We also propose reclassification of some Zar sequences. We found that Zar1 is expressed throughout oogenesis and is stable during oocyte maturation. The N-terminal domain of Zar1 repressed translation of a reporter construct in immature oocytes. Both Zar1 and Zar2 bound to the TCS in the Wee1 and Mos 3' UTRs using a zinc finger in the C-terminal domain. However, Zar1 had much higher affinity for RNA than Zar2. To show the functional significance of the conserved amino acid substitutions, these residues in Zar2 were mutated to those found in Zar1. We show that these residues contributed to the different RNA binding characteristics of Zar1 compared to Zar2. Our study shows that Zar proteins have generally similar molecular functions in the translational regulation of maternal mRNAs, but they may have different roles in early development.