1994 Fiscal Year Final Research Report Summary
Stability of beta_2-microglobulin in urine
| Project/Area Number |
04671439
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Laboratory medicine
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| Research Institution | Jichi Medical School |
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Principal Investigator |
ITOH Yoshihisa Jichi Medical School, Clinical Pathology, Assosiate Professor, 医学部, 助教授 (20129026)
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| Project Period (FY) |
1992 – 1994
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| Keywords | beta_2-microglobulin / Urine / Stability / NAG-B / alpha_1-microglobulin |
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| Research Abstract |
Urinary beta2-microglobulin (beta2-m) is quite unstable under acid conditions. The present study was undertaken to investigate the mechanisms of this instability in order to seek suitable sampling and preservation conditions.
1)beta2-m is most unstable of all 7 urinary proteins investigated : Common features of the proteins examined was that 1)all degraded at pH4.0 although alpha1-microglobulun relatively kept its antigenicity, 2)degradation was temperature dependent. However, beta2-m degradated markedly even at pH5.0. which contrasted other proteins. Sugar side chain is not an essential factor to determine the stability of proteins, but its own structure since non-glycoprotein, called protein 1, was quite stable as other glycoproteins.
Proteins in normal urine was unstable than those in pathologic urine. This may be explained by the decreased activity of proteases in urine which became similar to that in serum.
2)Fractionation of pathologic urine by chromatographies revealed that acid proteases are present in ConA-through fractions. Further studies are under way.
3)Development of an NAG-B isoenzyme immunoassays : NAG-B was purified from human placenta and its monoclonal antibody was thus prepared. Using this assay, the reference range was thus determined in normal urine. We discovered that NAG-B was rich in seminal plasma that can limit the clinical significance of this protein as a renal tubular marker.
4)Establishment of urinary alpha1-microglobulin assay : This protein proved to be most stable in urine.
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