| ForwardWith the development of microbubble contrast agent,The application not only embody on the field of imaging in clinic,also be foncus on the treatment by many people.Such as transfer gene to the infracted myocardium,medicine delivery, augmentation of thrombolysis,penetrate biological barrier and so on.Cavitation effect can make sound field energy highly focused in mini gas bubble with ultrasound function.When gas bubble blow up at a moment,physical and chemical effective will bring out high temperature,high energy,high pressure and severely destroy the surrounding of tissue and cells.Microbubble contrast agent can add the number of cavitation nudes and break out at the same cavitation processing.The shock wave may increase the ultrasound cavitation to the surrounding of tissue.The clot structure lack of the elasticity and collegan fibre.The texture is hard and fragile.Because the limitation of elasticity is little,the clots are easy to split and collapse.So people make use of the cavitation to break out the clots and let the medicine enter into the internal thrombus easily and improve the effect of thrombolysis.Early researches showed,ultrasound combined with microbubble contrast agent improve the thrombolysis,but frequency is lower than 1MHz,higher than 0.1W/cm2. Frequency and energy of diagnostic ultrasound both lower the therapy ultrasound,the aim of the experiment is to prove if the diagnostic ultrasound and microbubble contrast agent can augment thrombolysis in vitro and vivo study. Material and Method1.Health people blood 0.5ml,total 13.5ml,divided 9 group.Put in 37℃constant temperature box in plastic tube about 5～6 hours.Wash them by salt solution and dry,weight them by electronic scale.2.Health rat thirty-two,whether male or female,weight 2.5-3.0 kilogram,average (2.75±0.86) kilogram.3.Microbubble manufacture 5%albumin mix with 40%dextran and inject into CF3.Shake together.The product represent white solution,microbubble size 3～7μm.4.Accord to orthogonal table to conform the different group with ultrasound frequency(1.8 MHz,5 MHz,11 MHz),mechanical index(0.5,1.2,1.6),action time (10 min,30 min,60 min),microbubble concentration(3.5×109/ml,4.2×109/ml, 5.0×109/ml) and weight clots by electronic scale.Measure the rate of thrombolysis.5.HE stain the specimens and observe the structure of clots through electron microscope.6.Thirty-two rabbits of femoral vein thrombus were divided into four groups: simple urokinase group(UK),ultrasound and contrast microbubble group(US+MC), ultrasound and contrast microbubble combined with urokinase group(UK+US+ MC),control group.7.According to the best parameter combination which was definited in previous experiment,urokinase was added to the experiment.Color Doppler and integrated back scatter were used to evaluate the recanalization of different group8.The samples were conserved and stein them.Results1.The four factors all have statistic difference.The best combination is ultrasound frequency 1.8 MHz,mechanical index 1.6,action time 60 min,microbubble concentration 5.0×109/ml.2.HE stain showed original structure of clots and disaggregation of fibrous structure and the destruction of red cells in clot after 60min. 3.The electron microscope showed disaggregation of fibrous and rupture of cells and large inanity was found.4.Before the treatment,the rat femoral veins were blocked completely.After the treatment,there are slim blood flows in UK group and US+MC group.The condition become same.The femoral veins were almost clear in UK+US+MC group.5.In UK group,seven cases were observed recanalization.Three of them were gradedâ…¡class,four cases wereâ… class.In US+MC group,seven cases also were observed recanalization.Two of them were gradedâ…¡class,five cases wereâ… class.In UK+US+MC group,all of case showed recanalization,two of them were gradedâ…¢class,six of themâ…£class.6.After the experiment,BW/CD and BCA/CCA in UK+US+MC group both were higher than UK group,US+MC group(P＜0.01).7.IBS%is 0.65±0.02 in UK group,IBS%is 0.64±0.04 in US+MC group, 0.34±0.08 in UK+US+MC group,compared with control group 0.89±0.06,the results of three group all lower than it.The result in UK+US+MC group is also lower than UK group and US+MC group.8.The result of immunohistochemistry showed the thrombus was dissolved and venous lumen appeared again in UK+US+MC group after treatment.The result was better than US+MC group and UK group.Conclusion1.Diagnostic ultrasound with contrast microbubble can be used to definitely improve thrombolysis.2.The best thrombolysis factor is with ultrasound frequency1.8 MHz,mechanical index1.6,action time 60min,microbubble concentration 5.0×109/ml.3.Diagnostic ultrasound with microbubble contrast agent showed superior thrombolysis in vivo and if urokinase was added into the experiment with diagnostic ultrasound and microbubble contrast agent,the effect was apparently improved through the common action. |
PDF Full Text Request