Adams. JE Ill,. Bodor GS, D#{226}vila-Rom#{226}n. VG,. Delmez JA, Apple ES, Ladenson JH, et al. Cardiactroponin I. A marker with high specific- ity for cardiac.
Clinical Chemistry
the CK-MB mass index [100 X CK-MB mass (g/L)/total CK (U/L); reference 50 years old, Paget disease of bone is a common metabolic bone disorder often associated with pain and deformity. Active Paget disease is characterized by focally increased turnover of the extracellular matrix of bone, 90% of which in health is composed of normal type I collagen. Biochemically, the “gold standard” of Paget disease activity has been the finding of increased serum alkaline phosphatase (sAlkP) and increased concentrations of hydroxyproline excreted in the urine. More recently other, more sensitive, collagen type-specific methods have been introduced for measuring type I collagen turnover and include the aminoand carboxyl-terminal propeptides, intact PINP and PICP [1]. Measuring changes in these circulating biochemical markers of type I collagen synthesis would be a valuable method of monitoring collagen matrix turnover in Paget disease and the response to any therapeutic endeavor. Fibrillar collagens, such as type I collagen, are synthesized as extended molecules-.procollagens-with amino- and
PICP (.ig/L)
800
600
400 o
#{149}
0
200
--
0
#{149} S
S
I
0
200 Intact
I
400 PINP
600
800
lgig/L)
Fig. 1. Relation between intact PINP and PICP in active (#{149}) and quiescent (0) Paget disease of bone. Resultsfortwo cases with quiescent disease overlap. The broken lines enclose the reference intervals for healthy subjects, and the dotted line indicates the normal ratio between intact PINP and PICP in blood.
1122
creased (177 ± 65, range 69-281 .tg/L), with only 3 patients having values higher than the upper limit of the reference interval (202 g/L). The mean value of the PICP:PINP ratio was 0.79 ± 0.5. PINP correlated with PICP (r = 0.68, P
