Cryosurgery is an effective way of curing many diseases including tumors and cancers. It can be applied using a variety of systems and cryogens. Cheap, convenient, reliable equipment still needs to be developed so that cryotherapy may be accepted by surgeons and hospitals. This paper presents a cryosurgery apparatus that utilizes an auto-cascade refrigeration system. Refrigerant mixture R50/R23/R600a was selected as the working fluid. The mixture composition was altered to achieve lower temperatures and higher capacity. The lowest temperature at the cryoprobe could be as low as -100℃, and 8 W refrigeration capacity could be obtained at -80 ℃. An ice ball of 11.6 mm diameter could be formed when the cryoprobe was immersed in a water bath at 37 ℃.
Long-term preservation and easy transportation of human bone marrow-derived mesenchymal stem cells(hBM-MSCs) will facilitate their application in medical treatment and bioengineering.A pilot study on the freeze-drying of hBM-MSCs was carried out.hBM-MSCs were loaded with trehalose.The glass transition temperature of the freeze-drying suspension was measured to provide information for the cooling and primary drying experiment.After freeze-drying,various rehydration processes were tested.The highest recovery rate of hBM-MSCs was(69.33± 13.08) %.Possible methods to improve freeze-drying outcomes are discussed.In conclusion,the present study has laid a foundation for the freeze-drying hBM-MSCs.
Shao-zhi ZHANGHuan QIANZhen WANGJu-li FANQian ZHOUGuang-ming CHENRui LIShan FUJie SUN
Long-term preservation of human platelets will greatly reduce the risk of their shortage. Lyophilization has been proved feasible for this purpose. For the recovery of lyophilized platelets,rehydration is an important process. In this paper,the rehydration proc-esses for 1 mL and 2 mL samples were studied. The effects of prehydration duration(15,30,60,90,120 and 150 min) in 37°C water vapor and the concentration of rehydration solution(25%,50%,75%,100% platelet-poor plasma) on the recovery rate,MPV(mean platelet volume) and PDW(platelet distribution width) were investigated. The mass changes during the prehydration process were weighed. The optimized rehydration conditions are as follows:(1) for 1 mL sample,the prehydration duration was 15 min and for 2 mL sample the prehydration duration was 90 min;(2) the rehydration solution was 75% platelet-poor plasma. Under optimized conditions,the morphology of the rehydrated platelets kept normal and their ultrastructures kept intact,their aggregation capacity to thrombin(1 U/mL) was 82.8% of the fresh ones. These results will be helpful for designing the freeze-drying protocols for human platelets.
FAN JuLiXU XianGuoZHANG ShaoZhiXU MengJieZHU FaMingCHEN GuangMing
