Ere weighed, and their radioactivity was measured using a c-well counter, which was equipped with a NaI(Tl) crystal detector and coupled to a high gain PMT for maximum efficiency of 80 , along with a standard solution of the injection. Radioactivity results were recorded as the percentage injected activity per gram ( ID/g) of tissue corrected for background and decay.10 min was performed at 2 h. The maximum counts were recorded by drawing regions of interest (ROI) over the tumor and the homo-lateral muscle on the coronal images, 23388095 respectively. Tumor-to-muscle ratio was compared by the maximum counts.Detection of Tumor Vasculature by ImmunohistochemistryTumor vasculature was evaluated using immunohistochemical markers for endothelial cells (CD34). Tumor was paraffinembedded and routinely sectioned (5 mm) for staining with hematoxylin/eosin and by immunohistochemistry. Incubation with monoclonal mouse-anti-CD34 antibody was performed at room temperature for 1 h, after blocking endogenous peroxidase. Detection of the primary antibody was performed using biotinylated rabbit anti-mouse antibody (DAKO) and streptavidin-biotin NT 157 horseradish peroxidase complex. The peroxidase reaction was visualized using daminobenzidine/H2O2. Images were taken with a color CCD microscope system (Axiovert S100 with AxiocamHRc, Carl Zeiss) at a 1006 or 2006 magnification.Statistical AnalysisThe software SPSS 17.0 was used. All results are expressed as the mean 6 SD ( x 6 SD), and one-way ANOVA analysis was used. A P value,0.05 was considered to be statistically significant. Correlation analysis was used to explore the relationship between tumor size and tumor uptake.Tumor size versus tumor uptake15 BALB/c nu/nu mice with HepG2 xenografts were used in exploring the relationship between tumor size and tumor uptake. 4 h post injections of radiolabeled derivative, the mice were dissected and tumors were weighed. Diameters of tumors were also recorded, and their percentage injected activity ( ID) was calculated as biodistribution.Results Design and Synthesis of RRLThe RRL peptide (Gly-(D)Ala-Gly-Gly-Lys-(D)Ser-(D)Ser Cys-Gly-Gly-Arg-Arg-Leu-Gly-Gly-Cys-NH2) was successfully synthesized by SPPS method. (Fig. 1 and Fig. 2)Planar gamma imaging and Micro-PET Imaging12 BALB/c nu/nu mice with HepG2 xenografts were divided into 4 groups of 3 mice each (experimental, blocking, control and micro-PET group). The tumors were about 1 cm diameter for planar gamma or micro-PET imaging. In experimental group, 7.4 MBq 99mTc-RRL (100 ml, diluted with phosphate buffer, pH 7.4), which were purified and separated by Sephadex G25 gel-filtration column, were then injected 24786787 into each mouse via lateral tail vein. In blocking group, 500 mg unlabeled RRL was injected 30 minutes before injection of 99mTcRRL. In control group, each mouse was only administered with 7.4 MBq Na99mTcO4. All injections were successful with no leakage. A whole-body planar imaging was performed at 1, 2, 4 and 6 h after injection in the Department of Nuclear I-BRD9 manufacturer Medicine, Peking University First Hospital, using SPECT (SPR SPECT; GE Healthcare, Inc.) equipped with a low-energy, high-resolution, parallel-hole collimator. Planar images were acquired 200,000 counts with a zoom factor of 2.0, and were digitally stored in a 2566256 matrix size. In micro-PET group, the mice had been fasting for 10 h before 18 F-FDG injections but allowed free access to water. After intraperitoneally anesthetized with pentobarbital (100 mg/kg, Sigma-A.Ere weighed, and their radioactivity was measured using a c-well counter, which was equipped with a NaI(Tl) crystal detector and coupled to a high gain PMT for maximum efficiency of 80 , along with a standard solution of the injection. Radioactivity results were recorded as the percentage injected activity per gram ( ID/g) of tissue corrected for background and decay.10 min was performed at 2 h. The maximum counts were recorded by drawing regions of interest (ROI) over the tumor and the homo-lateral muscle on the coronal images, 23388095 respectively. Tumor-to-muscle ratio was compared by the maximum counts.Detection of Tumor Vasculature by ImmunohistochemistryTumor vasculature was evaluated using immunohistochemical markers for endothelial cells (CD34). Tumor was paraffinembedded and routinely sectioned (5 mm) for staining with hematoxylin/eosin and by immunohistochemistry. Incubation with monoclonal mouse-anti-CD34 antibody was performed at room temperature for 1 h, after blocking endogenous peroxidase. Detection of the primary antibody was performed using biotinylated rabbit anti-mouse antibody (DAKO) and streptavidin-biotin horseradish peroxidase complex. The peroxidase reaction was visualized using daminobenzidine/H2O2. Images were taken with a color CCD microscope system (Axiovert S100 with AxiocamHRc, Carl Zeiss) at a 1006 or 2006 magnification.Statistical AnalysisThe software SPSS 17.0 was used. All results are expressed as the mean 6 SD ( x 6 SD), and one-way ANOVA analysis was used. A P value,0.05 was considered to be statistically significant. Correlation analysis was used to explore the relationship between tumor size and tumor uptake.Tumor size versus tumor uptake15 BALB/c nu/nu mice with HepG2 xenografts were used in exploring the relationship between tumor size and tumor uptake. 4 h post injections of radiolabeled derivative, the mice were dissected and tumors were weighed. Diameters of tumors were also recorded, and their percentage injected activity ( ID) was calculated as biodistribution.Results Design and Synthesis of RRLThe RRL peptide (Gly-(D)Ala-Gly-Gly-Lys-(D)Ser-(D)Ser Cys-Gly-Gly-Arg-Arg-Leu-Gly-Gly-Cys-NH2) was successfully synthesized by SPPS method. (Fig. 1 and Fig. 2)Planar gamma imaging and Micro-PET Imaging12 BALB/c nu/nu mice with HepG2 xenografts were divided into 4 groups of 3 mice each (experimental, blocking, control and micro-PET group). The tumors were about 1 cm diameter for planar gamma or micro-PET imaging. In experimental group, 7.4 MBq 99mTc-RRL (100 ml, diluted with phosphate buffer, pH 7.4), which were purified and separated by Sephadex G25 gel-filtration column, were then injected 24786787 into each mouse via lateral tail vein. In blocking group, 500 mg unlabeled RRL was injected 30 minutes before injection of 99mTcRRL. In control group, each mouse was only administered with 7.4 MBq Na99mTcO4. All injections were successful with no leakage. A whole-body planar imaging was performed at 1, 2, 4 and 6 h after injection in the Department of Nuclear Medicine, Peking University First Hospital, using SPECT (SPR SPECT; GE Healthcare, Inc.) equipped with a low-energy, high-resolution, parallel-hole collimator. Planar images were acquired 200,000 counts with a zoom factor of 2.0, and were digitally stored in a 2566256 matrix size. In micro-PET group, the mice had been fasting for 10 h before 18 F-FDG injections but allowed free access to water. After intraperitoneally anesthetized with pentobarbital (100 mg/kg, Sigma-A.