Aim To introduce an improved method of Langendorff perfusion of the isolated rat heart that is easy to determine the termination of digestion.Methods Hearts were excised quickly from anesthetized SD rats.After the perfusate was free of blood,the solution was changed to perfusion buffer(0.6% Collagenase B,0.6% BSA,30 ?mol?L-1 Ca2+ in Tyrode solution)at 37℃.Hearts were isolated by traditional and improved Langendorff perfusion.Individual myocardial cell was measured by video-based motion edge-detection system(IonOptix,USA).Results One group of heart was digested by traditional Langendorff perfusion for 13~16 min.The termination of digestion could not be judged properly by this method.The nature and quality of the cardiocytes were various.The cardiocytes could not keep their survival and viability when exposed to Tyrode Solution with 1.8 mmol?L-1 Ca2+.Another group was digested by improved Langendorff perfusion.More than 80% survival cardiac ventricle myocytes could be obtained by improved Langendorff perfusion.Moreover,about 50% cardiac myocytes exposed to Tyrode solution with 1.8 mmol?L-1 Ca2+ could retain rod-shaped and be used to contraction research.The contraction of cardiocyte was stabile within 1 000 s.Conclusion Cardiac myocytes disassociated from improved Langendorff perfusion can be used in these studies of detecting contraction and relaxation.This method is economical and easy to control.The beginners are able to acquire the technological method over a short-term practice.

Noticing the phenomenon that biological tissues will change its elasticity by orders of magnitude after it was frozen, we proposed in principle the strategy of using ultrasound elastography to monitor the formation and thawing of the iceball when performing a cryosurgery. Following our former theoretical evaluation, conceptual experiments were designed to apply ultrasound elastography to monitor three kinds of testing samples which includes: phantom embedded with glass block, phantom with tissues at normal temperature and phantom with frozen tissues inside. It was demonstrated for the first time that the ultrasound elastography could provide a high contrast picture on the ice ball during cryosurgery. The measurement errors involved in the application of the method was preliminarily analyzed and approaches to further improve the method were pointed out. With a much different value in elastography than that of water, monitoring the ice ball, the imaging target in clinics, is expected to be an important area for the application of ultrasound elastography.
Cryosurgery ; methods ; Elasticity Imaging Techniques ; methods ; Phantoms, Imaging ; Ultrasonics

Objective To establish an animal model of calpastatin ( CAST) transgenic mice by inserting the full hu-man CAST into the genome of C57BL/6J mice.Methods Recombinant transgenic vector pRP .EX3d-EF1A-CAST-IRES-eGFP was constructed by Gateway technology .It was injected into the fertilized eggs from C 57BL/6J mice.The injected eggs were transplanted into the oviduct of pseudopregnant mice .Tail DNA PCR screening was performed to identify the positive founder mice.The expressions of CAST mRNA and protein in tissues of the transgenic mice were detected by RT -PCR and Western blotting.Results Ninty eggs were transplanted into the oviducts of 3 recipients.The transplantation success rate was 100%.23 viable offsprings were born from the recipients .Tail DNA PCR screening showed that two of the offsprings were positive transgenic mice .The positive rate of transgenic mice was 9%.RT-PCR assay revealed that CAST mRNA ex-pressions were present in the heart , liver, kidney, lung, spleen, brain and skeletal muscle of the transgenic mice .Addition-ally, the CAST protein expression was significantly increased in the transgenic mice .Conclusion CAST transgenic mice have been successfully established and provide a good animal model support for further studies on the CAST function .