Current topics are presented on four urinary proteins under investigations with special emphasis on importance of preanalytical sampling and assay standardization. These comprise of albumin, protein 1(P1), ภ2-microglobulin(ภ2-m), and Type IV collagen.
Microalbuminuria is an essential marker for early diabetic nephropathy.
The author is trying to reduce the discrepancy of urinary albumin value
with value assignment from CRM470, BCR international reference material,
to calibrator in each assay system. At the same time nonspecific binding
of the protein on urine containers were found, which can cause the discrepancy.
Furthermore structure of albumin both in calibrator and urine is important.
Protein 1 is a low molecular weight nonglycoprotein of 14kDa isolated from
pathologic urine. Marked sex-related difference was noted in urine, being
higher in male than female. This is due to the contamination from prostate.
Its localization was finally demonstrated with immunohistochemical staining
and a RT-PCR method. With the same methods the protein is demonstrated
to be synthesized in female prostate.
ภ2-m is easily degraded in acid urine. Employing various immunochemical methods
and analyses of its amino acid sequences, we successfully identified cathepsin
D as one of acid proteases responsible for the degradation. Urinary measurement
of type IV collagen is now clinically under use for an independent marker
for early diabetic nephropathy. Nonspecific elevation was observed in urine
with UTI, in which mechanism is should be clarified.
[Rinsho Byori 50 : 555`560, 2002]
*Department of Laboratory Medicine, Asahikawa Medical College, Asahikawa 078-8510
yKey Wordszurine(A)Calbumin(AAu~)Cprotein 1(veC 1)Cภ2-microglobulin(ภ2-}CNOu)CType IV collagen(IV ^R[Q)Cpreanalytical
sampling and preservation(ธOธ)
*ฎ์ใศๅwีฐธใwuภ(ง078-8510 ฎ์sฮชu2-1-1)
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E-mail :yoshiito@asahikawa-med.ac.jp