Thawing of the Frozen System

Vacuum Drying Books. (A) Frozen (or wet) books are placed in a chamber and heated by warm air. Vacuum is applied to remove water vapor as the ice thaws (5, 7). This is sometimes called the purged air system. (B) Frozen (or wet) books are placed in an unheated chamber. Moist air is evacuated and replaced with dry heated air (0% r.h.). When the replacement air becomes saturated with moisture, it is evacuated and the process repeated until the books are dry (4, 5). (C) Thawing books are put in a chamber. Vacuum is applied and then controlled at a pressure of about 5 torr. Heat is then applied to books through shelves to replace latent heat of vaporization. As moisture is released from books in vapor form (outgassing), it is collected by pumps and reverted to ice on cooled condensers in the chamber. After most of the water leaves the books, the book temperature is increased gradually from 32 °F to 80°-85°F the chamber is opened after 48 hr, the books are removed from the shelves, and the condensers are defrosted (4,5,10). 

The above mentioned dissociation of actomyosin into actin and myosin could be due to a shift in the equilibrium, actomyosin 5= actin + myosin, by the highly concentrated salt solution of the unfrozen liquid portion in the protein-water system (22, 77). However, if this is true, the dissociated actin and myosin must re-associate immediately after thawing. This may be difficult since the ability to associate is decreased during frozen storage. 

Fluosol s shortcomings included prolonged organ retention of F-tripropylamine (reticuloendothelial system (RES) half-life 65 days), complement activation, and hemodynamic effects due to Pluronic, excessive dilution, limited intravascular persistence, insufficient stability, and lack of user-friendliness. The product came as three separate preparations the frozen stem emulsion and two annex salt solutions. The stem emulsion had to be carefully thawed, then admixed sequentially to the annex solutions, and the reconstituted product had to be used within 8 h. This cumbersome procedure, the short window for use, the further need for administering a small-test dose to patients prior to infusion in order to identify those patients who were sensitive to Pluronic, contributed to compromising the product s commercial success. 

---