Vera D R, Stadalnik R C, Krohn K A
J Nucl Med. 1985 Oct;26(10):1157-67.
Technetium-99m galactosyl-neoglycoalbumin ([Tc] NGA), a labeled analog ligand to the hepatocyte-specific receptor, hepatic binding protein (HBP), was prepared and tested for labeling yield, stability, biodistribution, toxicity, and dosimetry. The ligand was synthesized by the covalent coupling of a carbohydrate bifunctional reagent, 2-imino-2-ethyloxymethyl-1-thiogalactose, to human serum albumin. Testing in mice and rabbits revealed the product to be nontoxic and apyrogenic. Technetium labeling yields in excess of 95%, by the electrolytic method, did not alter the molecular weight profile of the neoglycoalbumin. The NGA-bound activity remained stable for at least 4 hr. Biodistribution studies in rabbits demonstrated the liver as the single focus of tracer uptake. Dosimetry was based on kinetic studies in three baboons. Absorbed doses to liver, small intestine, urinary bladder wall, and uterus were 0.089, 0.28, 0.56, and 0.88 rad/mCi, respectively. Total body, lens of the eye, red marrow, ovaries, and testes were less than 0.06 rad/mCi. High liver specificity imparted by receptor binding combined with high labeling yield, stability, acceptable dosimetry, and safety provide [Tc]NGA with the attributes required for routine clinical assessment of hepatocyte function.
99m锝半乳糖基新糖白蛋白（[Tc]NGA），一种肝细胞特异性受体——肝结合蛋白（HBP）的标记类似物配体，已制备完成，并对其标记产率、稳定性、生物分布、毒性和剂量学进行了测试。该配体通过将碳水化合物双功能试剂2-亚氨基-2-乙氧基甲基-1-硫代半乳糖与人类血清白蛋白共价偶联合成。在小鼠和兔子身上的测试表明该产品无毒且无致热原性。通过电解法获得的锝标记产率超过95%，并未改变新糖白蛋白的分子量分布。与NGA结合的活性至少在4小时内保持稳定。在兔子身上进行的生物分布研究表明肝脏是示踪剂摄取的唯一部位。剂量学基于对三只狒狒的动力学研究。肝脏、小肠、膀胱壁和子宫的吸收剂量分别为0.089、0.28、0.56和0.88拉德/毫居里。全身、眼球晶状体、红骨髓、卵巢和睾丸的吸收剂量小于0.06拉德/毫居里。受体结合赋予的高肝脏特异性，结合高标记产率、稳定性、可接受的剂量学和安全性，为[Tc]NGA提供了常规临床评估肝细胞功能所需的特性。
