A Radioimmunometric Assay for Urinary .ALPHA.2-Macroglobulin.

Ito, Seiki; Usami, Akio; Yamazaki, Masatoshi; Shibata, Akira

doi:10.1620/tjem.176.137

Cited by 7 publications

(8 citation statements)

References 25 publications

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“…Urinary and serum IgG, IgG4, CRL [16], and A2 [17]were measured by immunoradiometric assay. In brief, 0.3 ml of coating antiserum was added to the assay tubes (Nunc), and the reaction was allowed to proceed at room temperature for 24 h. The tubes were washed three times with 0.4 ml of 0.1 M phosphate buffer (pH 7.4) containing 0.05% Tween 20, 0.3% bovine serum Alb, and 0.01% NaN 3 (washing buffer) and incubated with 0.4 ml of washing buffer overnight.…”

Section: Methodsmentioning

confidence: 99%

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Effects of Protein Meals on the Urinary Excretion of Various Plasma Proteins in Healthy Subjects

Narita

Kitazato²,

Koshimura³

et al. 1999

Nephron

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To examine whether hemodynamic changes in response to acute protein loadings with different protein sources cause increases in urinary excretion of plasma proteins in healthy subjects, urinary excretions of various plasma proteins with various molecular radii and isoelectric points, namely albumin (Alb), IgG, IgG4, ceruloplasmin (CRL), and α₂-macroglobulin (A2), were measured in healthy subjects after ingestion of a beef meal or of a tuna fish meal. Significant increases in urinary excretions of the negatively charged IgG4 and CRL and of the neutrally charged IgG were found in parallel with enhanced creatinine clearances after each protein ingestion. These renal responses returned to basal levels 9 h after the test. This finding suggests that in healthy subjects, the increase in glomerular filtration rate after acute protein loading caused selective enhancement of urinary excretions of plasma proteins with a molecular radius of approximately 55 Å (the radius of IgG, IgG4, and CRL), irrespective of the charge barrier of the glomerulus. The increases in these three plasma proteins may be induced by leakage via the shunt pathway in the glomerulus, as proposed earlier (see text). In contrast, increases in urinary excretions of A2 and Alb were not found. The former finding may be explained by the possibility that A2 would not pass through this pathway, since the molecular radius of A2 (88 Å) is larger than that of IgG, although the latter finding may be partially explained by preferential renal tubular reabsorption of Alb.

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Section: Methodsmentioning

confidence: 99%

“…To answer these questions, urinary excretions of various plasma proteins with various molecular radii and isoelectric points (pIs), namely albumin (Alb), IgG, IgG4, ceruloplasmin (CRL) [16], and α 2 -macroglobulin (A2) [17], were measured in healthy subjects after ingestion of a beef meal or of a tuna fish meal.…”

Section: Introductionmentioning

confidence: 99%

Effects of Protein Meals on the Urinary Excretion of Various Plasma Proteins in Healthy Subjects

Narita

Kitazato²,

Koshimura³

et al. 1999

Nephron

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“…Several of the proteins identified have been previously described as potential biomarkers of glomerulopathies, such as a 2 -macroglobulin (a 2 -M) and alpha-1anti-trypsin (AAT). a 2 -M, a 720-kDa glycoprotein mainly synthesized in the liver, was demonstrated to be increased in plasma and urine of patients with nephrotic syndrome regardless of the primary disease, and was suggested to be a marker of glomerular diseases [18][19][20][21]. Thus, in a study investigating 199 patients with renal biopsy-proven glomerulopathies, Tencer et al [20] suggested that the urinary a 2 -M selectivity index could be used to effectively distinguish two types of glomerular disorders (minimal change nephropathy and crescentic necrotizing glomerulonephritis) from all the other analyzed glomerular diseases.…”

Section: Proteomic Analysis Of the Podocytes Vesicle-enriched Urinarymentioning

confidence: 99%

Proteomic analysis of a podocyte vesicle‐enriched fraction from human normal and pathological urine samples

Lescuyer¹,

Pernin

Hainard³

et al. 2008

Proteomics Clinical Apps

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Podocytes (glomerular visceral epithelial cells) release vesicles into urine. Podocyte vesicle-enriched fractions from normal and pathological human urine samples were prepared for proteomic analysis. An immunoadsorption method was applied and enrichment of podocyte vesicles was assessed. We identified 76 unique proteins. One protein, serum paraoxonase/arylesterase 1 (PON-1), was newly identified in normal human urine sample. We confirmed this result and showed PON-1 expression in normal human kidney. These results demonstrated the potential for using the urine samples enriched in podocyte vesicles as a starting material in studies aimed at discovery of biomarkers for diseases.

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“…Concentrations of IgG, ceruloplasmin, and ␣ 2 -macroglobulin of serum and urine samples were measured by immunoradiometric assay according to procedures previously reported (4,9,12,18). Intraand interassay coefficient variances for the assays of these plasma proteins were almost 3 and 10%, respectively.…”

Section: Laboratory Proceduresmentioning

confidence: 99%

Parallel Increase in Urinary Excretion Rates of Immunoglobulin G, Ceruloplasmin, Transferrin, and Orosomucoid in Normoalbuminuric Type 2 Diabetic Patients

et al. 2004

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OBJECTIVE -Increased urinary excretions of several plasma proteins with different molecular radii Ͻ55 Å and different isoelectric points (pI), such as IgG, ceruloplasmin, transferrin, and orosomucoid, have been independently reported to precede the development of microalbuminuria in diabetic patients. We examined whether increases in urinary excretions of these proteins would be in parallel in the same patient.RESEARCH DESIGN AND METHODS -Urinary excretion rates of proteins mentioned above in timed overnight urine samples were evaluated in 61 normoalbuminuric type 2 diabetic patients (group D) aged 40 -60 years and in 17 age-matched control subjects (group C).RESULTS -The excretion rates of these proteins were significantly higher in group D than in group C. These exhibited a strong linear correlation with each other and had a weak correlation with the excretion rate of N-acethylglucosaminidase. The excretion rate of ␣ 2 -macroglobulin with large molecular radii of 88 Å was not different between groups C and D, nor did they have any correlations with the excretion rates of the other proteins. Creatinine clearance and blood pressure levels in group D were significantly higher than those in group C. CONCLUSIONS -In normoalbuminuric diabetic patients, excretion rates of plasma proteins with molecular radii Ͻ55 Å increased in parallel with each other. In view of our previous finding that urinary excretions of these plasma proteins selectively increased in parallel with enhanced glomerular filtration rate after acute protein loading, the present finding may be explained by renal hemodynamic changes, such as increased intraglomerular hydraulic pressure. Diabetes Care 27:1176 -1181, 2004D iabetic nephropathy is the most frequent cause of entering renal replacement therapy in industrialized countries such as the U.S., European countries, Australia, New Zealand, and Japan (1). Early recognition of renal changes increases the chance of preventing the development of diabetic nephropathy. Although microalbuminuria is generally recognized as the best available noninvasive predictor of diabetic nephropathy, several studies including ours have shown that increased urinary excretions of some kinds of plasma proteins with different molecular radii Ͻ55 Å and different isoelectric points (pIs) such as IgG (2-4), transferrin (5-8), ceruloplasmin (4,9), and orosomucoid (10) may precede the development of microalbuminuria in diabetic patients. Kazumi et al. (11) reported that increased urinary transferrin excretion could predict the development of microalbuminuria in type 2 diabetic patients.Recently, we found that urinary excretions of plasma proteins with molecular radii Ͻ55 Å (IgG, IgG4, ceruloplasmin, transferrin, and orosomucoid, abbreviated to small-sized plasma proteins group [SPP]) selectively increased irrespective of their pI despite no increased urinary excretion of albumin (molecular radii ϭ 36 Å, smaller than that of IgG, IgG4, and ceruloplasmin) when glomerular filtration rate (GFR) was increased by acute protein load...

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A Radioimmunometric Assay for Urinary .ALPHA.2-Macroglobulin.

Cited by 7 publications

References 25 publications

Effects of Protein Meals on the Urinary Excretion of Various Plasma Proteins in Healthy Subjects

Effects of Protein Meals on the Urinary Excretion of Various Plasma Proteins in Healthy Subjects

Proteomic analysis of a podocyte vesicle‐enriched fraction from human normal and pathological urine samples

Parallel Increase in Urinary Excretion Rates of Immunoglobulin G, Ceruloplasmin, Transferrin, and Orosomucoid in Normoalbuminuric Type 2 Diabetic Patients

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