Pimm M V, Perkins A C, Gribben S J, Hudecz F
Cancer Research Laboratories, University of Nottingham, UK.
J Nucl Biol Med (1991). 1994 Dec;38(4 Suppl 1):104-8.
A branched polypeptide drug carrier, with a poly(L-lysine) backbone, has been labelled with 111In and its biodistribution imaged in mice with transplanted B16 melanoma. Levels of tracer in tumours were not great enough for tumours to be discerned on gamma-camera images, and this was confirmed by subsequent dissection analysis. Tumour levels of 111In from labelled polymer were about 3% of the dose g-1 two days after injection. Similar levels of tracer were found in tumour tissue of mice injected with mouse immunoglobulin or serum albumin labelled with 111In by DTPA chelation, or injected with free 111In-chloride to label serum transferrin. There was rapid excretion of a sub-component of the 111In-labelled polymer visible in the images. Gel permeation chromatography suggested that the polymer was heterogeneous, some components having Stoke's radii below that allowing renal clearance. Gel permeation chromatography was used to separate labelled polymer into fractions having high, intermediate and low renal clearance. The low-excretion fraction showed a two-fold increase in tumour levels, compared with native polymer, although as this fraction showed greater survival in the blood and body as a whole, discrimination between tumour and normal tissue was not increased.
一种以聚（L-赖氨酸）为主链的分支多肽药物载体已用铟-111进行标记，并在移植了B16黑色素瘤的小鼠体内对其生物分布进行成像。肿瘤中的示踪剂水平不足以在γ相机图像上辨别出肿瘤，后续的解剖分析证实了这一点。注射两天后，标记聚合物中的铟-111在肿瘤中的水平约为剂量的3%/克。在用二乙三胺五乙酸螯合标记的小鼠免疫球蛋白或血清白蛋白注射的小鼠肿瘤组织中，或用游离的氯化铟-111注射以标记血清转铁蛋白的小鼠肿瘤组织中，发现了相似水平的示踪剂。图像中可见铟-111标记聚合物的一个亚组分迅速排泄。凝胶渗透色谱法表明该聚合物是异质的，一些组分的斯托克斯半径低于肾清除阈值。凝胶渗透色谱法用于将标记聚合物分离成具有高、中、低肾清除率的组分。与天然聚合物相比，低排泄组分在肿瘤中的水平增加了两倍，尽管由于该组分在血液和整个身体中的存留时间更长，肿瘤与正常组织之间的区分度并未提高。
