Table 4.

Human CSF and plasma cathepsin B concentrations.

Sample (number of individuals)	Measured concentrationc ng/mL	Estimated molar concentrationd μmol/L	Reference
CSF (118)a	8.4	3.36 × 10−4	(175)
CSF (28)b	9.6 ± 3.4	3.84 × 10−4	(130)
Plasma (28)b	134.3 ± 71.3	53.7 × 10−4	(130)

^aSurgery patients, 21–82 years old, mean age 65 years, predominately male.

^bHealthy volunteers, mean age 63.9 ± 6.2 years old, predominately female.

^cValue reported by reference, mean ± SD.

^dEstimated value to facilitate comparison with Table 5 data assuming a cathepsin B molecular weight of 25,000.