Objective—To validate a radioimmunoassay for measurement of procollagen type III amino terminal propeptide (PIIINP) concentrations in canine serum and bronchoalveolar lavage fluid (BALF) and investigate the effects of physiologic and pathologic conditions on PIIINP concentrations.
Sample Population—Sera from healthy adult (n = 70) and growing dogs (20) and dogs with chronic renal failure (CRF; 10), cardiomyopathy (CMP; 12), or degenerative valve disease (DVD; 26); and sera and BALF from dogs with chronic bronchopneumopathy (CBP; 15) and healthy control dogs (10 growing and 9 adult dogs).
Procedure—A radioimmunoassay was validated, and a reference range for serum PIIINP (S-PIIINP) concentration was established. Effects of growth, age, sex, weight, CRF, and heart failure on S-PIIINP concentration were analyzed. In CBP-affected dogs, S-PIIINP and BALF-PIIINP concentrations were evaluated.
Results—The radioimmunoassay had good sensitivity, linearity, precision, and reproducibility and reasonable accuracy for measurement of S-PIIINP and BALF-PIIINP concentrations. The S-PIIINP concentration reference range in adult dogs was 8.86 to 11.48 μg/L. Serum PIIINP concentration correlated with weight and age. Growing dogs had significantly higher S-PIIINP concentrations than adults, but concentrations in CRF-, CMP-, DVD-, or CBP-affected dogs were not significantly different from control values. Mean BALF-PIIINP concentration was significantly higher in CBP-affected dogs than in healthy adults.
Conclusions and Clinical Relevance—In dogs, renal or cardiac disease or CBP did not significantly affect S-PIIINP concentration; dogs with CBP had high BALF-PIIINP concentrations. Data suggest that the use of PIIINP as a marker of pathologic fibrosis might be limited in growing dogs.
Objective—To evaluate a human assay for quantification
of carboxy-terminal cross-linking telopeptide of
type I collagen (CTX-I), assess the influence of age on
plasma CTX-I concentration, investigate the relationship
between plasma CTX-I and serum osteocalcin
concentrations, and determine whether concentrations
of plasma CTX-I or serum osteocalcin fluctuate
in circadian manner in horses.
Horses—75 clinically normal horses.
Procedure—Cross-reactivity between equine serum
CTX-I and CTX-I antibodies in an automated electrochemiluminescent
sandwich antibody assay (ECLIA)
was evaluated via a specificity test (ie, dilution test) and
recovery calculation. Serum osteocalcin concentration
was measured with an equine-specific osteocalcin
radioimmunoassay. To analyze diurnal variations in plasma
CTX-I and serum osteocalcin concentrations, blood
samples were obtained hourly during a 24-hour period.
Results—Results of the dilution test indicated good
correlation ( r > 0.99) between expected serum CTX-I
concentrations and measured serum CTX-I concentrations.
The calculated CTX-I recovery was 97.6% to
109.9%. Plasma CTX-I and serum osteocalcin concentrations
were correlated. Plasma CTX-I concentration
was inversely correlated with age of the horse.
No significant circadian variations in plasma CTX-I and
serum osteocalcin concentrations were detected.
Conclusions and Clinical Relevance—Results suggest
that the fully automated CTX-I ECLIA can be
used for evaluation of plasma and serum samples
from horses and may be a useful tool to monitor bone
metabolism changes. Horses in this study did not
have notable diurnal fluctuations in serum osteocalcin
and plasma CTX-I concentrations. ( Am J Vet Res 2004;65:104–109)