Analytic expressions have been derived of the alternating current(ac)Zeeman and ac Stark effect in an atomic beam magnetic resonance method using Ramsey separated oscillating fields.An interesting feature which will a...Analytic expressions have been derived of the alternating current(ac)Zeeman and ac Stark effect in an atomic beam magnetic resonance method using Ramsey separated oscillating fields.An interesting feature which will affect the normal Ramsey pattern is that an interference fringe is superimposed on the dispersion lineshapes of the normal ac Zeeman or ac Stark effect.We point out that this new character of ac Zeeman(ac Stark)effect generally exists in all kinds of Ramsey method,for example,in the optical Ramsey atomic interferometer and atomic beam frequency standard.An important implication is that,particularly in an atomic beam frequency standard using Ramsey method,this effect has an influence on the evaluation of the second-order Doppler frequency shift.展开更多
Background Experimental studies and preliminary clinical studies have suggested that growth hormone （GH） treatment may improve cardiovascular parameters in chronic heart failure （CHF）. Recombinant human GH （rhGH...Background Experimental studies and preliminary clinical studies have suggested that growth hormone （GH） treatment may improve cardiovascular parameters in chronic heart failure （CHF）. Recombinant human GH （rhGH） has been delivered by a recombinant protein, by plasmid DNA, and by genetically engineered cells with different pharmacokinetic and physiological properties. The present study aimed to examine a new method for delivery of rhGH using genetically modified bioartificial muscles （BAMs）, and investigate whether the rhGH delivered by this technique improves left ventricular （LV） function in rats with CHE Methods Primary skeletal myoblasts were isolated from several Sprague-Dawley （SD） rats, cultured, purified, and retrovirally transduced to synthesize and secrete human rhGH, and tissue-engineered into implantable BAMs. Ligation of the left coronary artery or sham operation was performed. The rats that underwent ligation were randomly assigned to 2 groups： CHF control group （n=6） and CHF treatment group （n=6）. The CHF control group received non-rhGH-secreting BAM （GFP-BAMs） transplantation, and the CHF treatment group received rhGH-secreting BAM （GH-BAMs） transplantation. Another group of rats served as the sham operation group, which was also randomly assigned to 2 subgroups： sham control group （n=6） and sham treatment group （n=6）. The sham control group underwent GFP-BAM transplantation, and the sham treatment group underwent GH-BAM transplantation. GH-BAMs and GFP-BAMs were implanted subcutaneously into syngeneic rats with ligation of the left coronary artery or sham operation was performed. Eight weeks after the treatment, echocardiography was performed, hGH, insulin-like growth factor-1 （IGF-1） and TNF-a levels in rat serum were measured by radioimmunoassay and ELISA, and then the rats were killed and ventricular samples were subjected to immunohistochemistry. Results Primary rat myoblasts were retrovirally transduced to secrete rhGH and tissue-engineered into implantable BAMs containing parallel arrays of postmitotic myofibers. In vitro, they secreted 1 to 2 lug of bioactive rhGH per day. When implanted into syngeneic rat, GH-BAMs secreted and delivered rhGH. Eight weeks after therapy, LV ejection fraction （EF） and fractional shortening （FS） were significantly higher in CHF rats treated with GH-BAMs than in those treated with GFP-BAMs （（65.0i-6.5）% vs （48.1±6.8）%, P 〈0.05）, （（41.3±7.4）% VS （26.5±7.1）%, P 〈0.05）. LV end-diastolic dimension （LVEDD） was significantly lower in CHF rats treated with GH-BAM than in CHF rats treated with GFP-BAM （P 〈0.05）. The levels of serum GH and IGF-1 were increased significantly in both CHF and sham rats treated with GH-BAM. The level of serum TNF-α decreased more significantly in the CHF treatment group than in the CHF control group.Conclusions rhGH significantly improves LV function and prevents cardiac remodeling in rats with CHF. Genetically modified tissue-engineered bioartificial muscle provides a method delivering recombinant protein for the treatment of heart failure.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.69678031the Foundation for University Key Teacher by the Education Ministry of China.
文摘Analytic expressions have been derived of the alternating current(ac)Zeeman and ac Stark effect in an atomic beam magnetic resonance method using Ramsey separated oscillating fields.An interesting feature which will affect the normal Ramsey pattern is that an interference fringe is superimposed on the dispersion lineshapes of the normal ac Zeeman or ac Stark effect.We point out that this new character of ac Zeeman(ac Stark)effect generally exists in all kinds of Ramsey method,for example,in the optical Ramsey atomic interferometer and atomic beam frequency standard.An important implication is that,particularly in an atomic beam frequency standard using Ramsey method,this effect has an influence on the evaluation of the second-order Doppler frequency shift.
基金This work was supported by grants from the National High-Technology Research and Development Program of China （863 Program） （No. 2002AA745070）, Shanxi Province Natural Science Foundation （No. 2009011055-4）, and Scientific Research Foundation of High Education Institutions of Shanxi Province, China （No. 200811034）.
文摘Background Experimental studies and preliminary clinical studies have suggested that growth hormone （GH） treatment may improve cardiovascular parameters in chronic heart failure （CHF）. Recombinant human GH （rhGH） has been delivered by a recombinant protein, by plasmid DNA, and by genetically engineered cells with different pharmacokinetic and physiological properties. The present study aimed to examine a new method for delivery of rhGH using genetically modified bioartificial muscles （BAMs）, and investigate whether the rhGH delivered by this technique improves left ventricular （LV） function in rats with CHE Methods Primary skeletal myoblasts were isolated from several Sprague-Dawley （SD） rats, cultured, purified, and retrovirally transduced to synthesize and secrete human rhGH, and tissue-engineered into implantable BAMs. Ligation of the left coronary artery or sham operation was performed. The rats that underwent ligation were randomly assigned to 2 groups： CHF control group （n=6） and CHF treatment group （n=6）. The CHF control group received non-rhGH-secreting BAM （GFP-BAMs） transplantation, and the CHF treatment group received rhGH-secreting BAM （GH-BAMs） transplantation. Another group of rats served as the sham operation group, which was also randomly assigned to 2 subgroups： sham control group （n=6） and sham treatment group （n=6）. The sham control group underwent GFP-BAM transplantation, and the sham treatment group underwent GH-BAM transplantation. GH-BAMs and GFP-BAMs were implanted subcutaneously into syngeneic rats with ligation of the left coronary artery or sham operation was performed. Eight weeks after the treatment, echocardiography was performed, hGH, insulin-like growth factor-1 （IGF-1） and TNF-a levels in rat serum were measured by radioimmunoassay and ELISA, and then the rats were killed and ventricular samples were subjected to immunohistochemistry. Results Primary rat myoblasts were retrovirally transduced to secrete rhGH and tissue-engineered into implantable BAMs containing parallel arrays of postmitotic myofibers. In vitro, they secreted 1 to 2 lug of bioactive rhGH per day. When implanted into syngeneic rat, GH-BAMs secreted and delivered rhGH. Eight weeks after therapy, LV ejection fraction （EF） and fractional shortening （FS） were significantly higher in CHF rats treated with GH-BAMs than in those treated with GFP-BAMs （（65.0i-6.5）% vs （48.1±6.8）%, P 〈0.05）, （（41.3±7.4）% VS （26.5±7.1）%, P 〈0.05）. LV end-diastolic dimension （LVEDD） was significantly lower in CHF rats treated with GH-BAM than in CHF rats treated with GFP-BAM （P 〈0.05）. The levels of serum GH and IGF-1 were increased significantly in both CHF and sham rats treated with GH-BAM. The level of serum TNF-α decreased more significantly in the CHF treatment group than in the CHF control group.Conclusions rhGH significantly improves LV function and prevents cardiac remodeling in rats with CHF. Genetically modified tissue-engineered bioartificial muscle provides a method delivering recombinant protein for the treatment of heart failure.
