- Radioimmunoassay for human pancreatic secretory trypsin inhibitor: measurement of serum pancreatic secretory trypsin inhibitor in normal subjects and subjects with pancreatic diseases. Kitahara, T., Takatsuka, Y., Fujimoto, K.I., Tanaka, S., Ogawa, M., Kosaki, G. Clin. Chim. Acta (1980)