Application of plasma clearance of iohexol in evaluating renal function in chinese children with chronic kidney disease / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the accuracy of plasma clearance of iohexol (PCio) for glomerular filtration rate (GFR) measurement in Chinese children with chronic kidney disease (CKD) and assess the feasibility of single-blood-sample method or dried capillary blood spots in determining the PCio.</p><p><b>METHODS</b>Totally 45 CKD children were included,in whom the (99m) Technetium-diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) plasma clearance and iohexol plasma clearance were simultaneously determined. Blood samples were obtained 2,4,and 5 hours after injection. In addition, we also evaluated the efficacy of single blood sample method and dried blood spots method in iohexol plasma clearance.</p><p><b>RESULTS</b>Forty-five CKD children completed the iohexol plasma clearance and thirty-six children completed the (99m)Tc-DTPA plasma clearance at the same time among them. Thirteen children finished the iohexol dried blood spot clearance. The correlation coefficient between (99m)Tc-DTPA plasma clearance and iohexol plasma clearance was 0.941 and the bias was (6.53 ± 11.6) ml/ (min·1.73 m²), and the intraclass correlation coefficient (ICC) was high (ICC=0.947). The correlation between iohexol single-sample plasma clearance and double samples was also strong (r=0.958), with the bias being (4.26 ± 9.06)ml/(min·1.73 m²) and the ICC being 0.970. The iohexol clearance by dried blood spots showed a good correlation with the serum iohexol clearance (r=0.950), with the bias still being small [(0.48 ± 10.89)ml/(min·1.73 m²)].</p><p><b>CONCLUSIONS</b>Iohexol plasma clearance has satisfactory agreement with (99m)Tc-DTPA plasma clearance and can be used as an ideal method to measure GFR in CKD children. The single-sample method and dried blood spots method make iohexol plasma clearance more convenient and practical.</p>

Imaging of 99Tcm-labeled new cyclic RGDfK Dimer in nude mice bearing U87MG human glioma xenografts / 中华核医学杂志

Objective (1) To evaluate the effect of insertion of two 15-amino-4,7,10,13-tetraoxapentadecanoic (2 PEG4 ) linkers into cyclic Arg-Gly-Asp (RGD) Dimer E [c(RGDfK)]2 on receptor binding in vitro, (2) to assess its biodistribution in vivo and (3) to investigate the value of 99Tcm labeled 2PEG4-Dimer for integrin αvβ3-positive tumors imaging.Methods The expression of U87 human glioma cells and integrin αv β3 was determined by immunofluorescence staining.The half-inhibition concentrations (IC50) for 125 I-cyclo (Arg-Gly-Asp-D-Tyr-Lys) (c(RGDyK) ) of c ( RGDyK ), hydrazinonictinamide ( HYNIC )-Dimer and HYNIC-2PEG4-Dimer binding to integrin αvβ3 were measured.99Tcm-HYNIC-Dimer and 99Tcm-HYNIC-2PEG4-Dimer were synthesized using non-SnCl2 formulation.Biodistribution and imaging studies were performed in nude mice bearing human glioma xenografts.The unpaired t test was used for statistical analysis.Results The labeling yield of the two radiotracers was more than 95%, and the radiochemical purity was more than 99% through Sep-Pek C18 cartridge.HYNIC-2PEG4-Dimer had significantly higher binding affinity of integrin αvβ3 than c(RGDyK) and HYNIC-Dimer (IC50 = 0.8 nmol/L, 27 nmol/L and 2.4 nmol/L, respectively).Biodistribution study showed that 99Tcm-HYNIC-2PEG4-Dimer was mainly excreted via the kidney.The tumor uptake of 99Tcm-HYNIC-2PEG4-Dimer was higher than that of 99Tcm-HYNIC-Dimer at 2h post injection ((5.71 ±0.96) and (2.10 ±0.50) % ID/g, t =4.80, P＜0.05).The xenografted tumors were visible at 0.5 h post injection and the image contrast increased with time due to the tracer clearance of the background tissue.Conclusion 99 Tcm-HYNIC-2PEG4-Dimer is a promising radiotracer for integrin αvβ3-positive tumor imaging.