This paper describes the development of ∨99mTc tricarbonyl cysteine as potential renal function diagnostic radiopharmaceutical and evaluation of its biological characteristics using experimental animals. ℓ-Cysteine was labeled efficiently with ∨99mTc tricarbonyl precursor ([∨99mTc(CO)₃(H₂O)₃)]+) under 30 min heating at 75℃. Labeling yield and stability were analyzed by high performance liquid chromatography (HPLC). The biodistribution property of ∨99mTc tricarbonyl cysteine in mice and its dynamic imaging profiles in rabbits were carried out.

The proteolytic activities present in midguts of both fed and unfed Haemaphysalis longicornis were assessed by using the gelatin-substrate gel electrophoresis and inhibitor sensitivity analyses. Three predominant (116, 48 and 40 kDa) and two weak (55 and 60 kDa) proteinase bands were commonly expressed in both unfed and fed ticks, while a weak 80 kDa band was only present in fed ticks. Consistent with observations on other tick species, proteolytic activity against the gelatin substrate was observed only under acidic conditions. Inhibition studies against the gelatin substrate using a panel of inhibitors showed that the predominant proteolytic enzymes of 40 and 48 kDa molecular mass are cysteine proteinases. These results are discussed in the context of host vaccination as an alternative tick control method to the current use of chemical acaricides