Radioimmunological Quantitation of Urinary Trypsin Inhibitor

Usui, Tsuguru; Maehara, Susumu; Kawashita, Eiso; Ishibe, Tomoyuki; Sumi, Hiroyuki; Toki, Naotika

doi:10.1159/000469492

Cited by 5 publications

(3 citation statements)

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“…UTI, but not I␣I, was originally found in urine. UTI is excreted in urine at a rate of several miligrams per day from healthy subjects [37] or at a concentration of about 5 ϫ 10 Ϫ7 M (unpublished data; Kobayashi et al). Although some information is available, the physiological function of I␣I and UTI is still obscure.…”

Section: Discussionmentioning

confidence: 99%

Identification of structural domains in inter-α-trypsin inhibitor involved in calcium oxalate crystallization

Kobayashi

Shibata

Fujie

et al. 1998

Kidney International

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The urinary glycoprotein that inhibits calcium oxalate (CaOx) crystallization in vitro shows a structural similarity to urinary trypsin inhibitor (UTI; recently termed bikunin), the light chain of inter-alpha-trypsin inhibitor (I alpha I). The functional domains of I alpha I involved in its inhibitory activity of CaOx crystallization have been investigated using isolated intact domains of I alpha I produced from controlled proteolytic digests of the protein. The fragments investigated include the heavy chains of I alpha I, UTI, chondroitinase AC-treated UTI, and the carboxyl-terminal domain of UTI (termed HI-8). The effects of I alpha I and its fragments on the inhibitory activity of CaOx crystallization were evaluated in vitro using CaOx crystal aggregation and growth assays, and seeded crystal generation assay as well as using crystal matrix protein generation assay. UTI, but not the heavy chains of I alpha I, had a discernible effect on CaOx crystallization inhibitory activity. Less requirement of the carbohydrate moiety of UTI is implicated by the observation that chondroitinase AC-treated UTI fragment was also found to inhibit CaOx crystallization with almost the same activity as UTI. HI-8 also efficiently inhibited CaOx crystallization, while I alpha I showed a weak inhibitory activity. The results are almost consistent with a seed crystal generation assay and a crystal adsorption inhibition assay, in which I alpha I or its derivatives inhibits prothrombin fragment 1 (F1) adsorption to CaOx crystals. In conclusion, these results suggest that the part of the I alpha I protein responsible for inhibition of CaOx crystallization is the carboxyl-terminal domain of UTI.

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Section: Discussionmentioning

confidence: 99%

Identification of structural domains in inter-α-trypsin inhibitor involved in calcium oxalate crystallization

Kobayashi

Shibata

Fujie

et al. 1998

Kidney International

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“…Both heavy and light chains have been identified in the urine (184)(185)(186)(187)(188)(189)(190)(191)(192)(193)(194)(195)(196)(197)(198)(199). The average concentration of IαI in the plasma of healthy human subjects is approximately 450 mg/l (196).…”

Section: Inter-α-inhibitormentioning

confidence: 99%

“…Several investigators have determined the concentration of bikunin in the normal human urine. Some of the published values are: 0.225-0.650 µg/ml (191), 5.01 + 0.91 µg/ml (190), 10.13 + 1.13 µg/ml and 6.72 + 0.93 µg/ml in normal men and women respectively (192), 4.82 + 2.46 mg/day and 3.86 + 1.35 mg/day in normal men and women respectively (193), and 17.5 mg/day (197). It has been suggested that most of these values are overestimation since quantification employed immunoassays using polyclonal antibodies against bikunin.…”

Section: Inter-α-inhibitormentioning

confidence: 99%

Modulators of urinary stone formation

2004

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Urine contains compounds that modulate the nucleation, growth and aggregation of crystals as well as their attachment to renal epithelial cells. These compounds may function to protect the kidneys against: 1, the possibility of crystallization in tubular fluid and urine, which are generally metastable with respect to calcium salts, 2, crystal retention within the kidneys thereby preventing stone formation and 3, possibly against plaque formation at the nephron basement membrane. Since oxalate is the most common stone type, the effect of various modulators on calcium oxalate (CaOx) crystallization has been examined in greater details. Most of the inhibitory activity resides in macromolecules such as glycoproteins and glycosaminoglycans while nucleation promotion activity is most likely sustained by membrane lipids. Nephrocalcin, Tamm-Horsfall protein, osteopontin, urinary prothrombin fragment 1, and bikunin are the most studied inhibitory proteins while chondroitin sulfate (CS), heparan sulfate (HS) and hyaluronic acid (HA) are the best studied glycosaminoglycans. Crystallization modulating macromolecules discussed here are also prominent in cell injury, inflammation and recovery. Renal epithelial cells on exposure to oxalate and CaOx crystals produce some of the inflammatory molecules such as monocyte chemoattractant protein-1 (MCP-1) with no apparent role in crystal formation. In addition, macrophages surround the CaOx crystals present in the renal interstitium. These observations indicate a close relationship between inflammation and nephrolithiasis.

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Development of an ELISA Test for Determination of the Urinary Trypsin Inhibitor: Analytical Performance and Applications

D'Ercole

Priori

Pucciarelli

et al. 2005

J. of Immunoassay & Immunochemistry

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Increased urinary excretion of urinary trypsin inhibitor (UTI) has been reported in various inflammatory conditions and in Alzheimer's subjects, but its diagnostic potential remains to be elucidated. A reliable and specific enzyme-linked immunosorbent assay (ELISA) test for the determination of the UTI in human urine was developed. This assay was performed using 96-well microtiter plates. The plate surface is coated with an anti-UTI polyclonal antibody, the urine sample was added in a dilution range, and the detection was achieved using the enzyme-conjugated antibody. The assay was quantified by the build-up of colored product upon the addition of the substrate. Recoveries were 93%, and the intra- and inter-assay CVs were 4.25% and 21%, respectively. The ELISA showed parallelism of standard and urine samples and no significant interference by the biological matrix. The usefulness of the assay has been demonstrated by applying it to urine samples from Alzheimer's disease patients, and comparing with negative controls. UTI urinary levels are significantly increased in Alzheimer's subjects.

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Radioimmunological Quantitation of Urinary Trypsin Inhibitor

Cited by 5 publications

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Identification of structural domains in inter-α-trypsin inhibitor involved in calcium oxalate crystallization

Identification of structural domains in inter-α-trypsin inhibitor involved in calcium oxalate crystallization

Modulators of urinary stone formation

Development of an ELISA Test for Determination of the Urinary Trypsin Inhibitor: Analytical Performance and Applications

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