Showing papers by "Per A. Peterson published in 1971"

Radioimmunoassay of 2 -microglobulin in human biological fluids.

Abstract: A radioimmunoassay has been employed for quantitation of β2-microglobulin in human biological fluids. The average β2-microglobulin amounts in serum and urine from 10 healthy subjects were 1.5 mg/1 and 0.073 mg/24 hour volume, respectively, and in serum, saliva, and colostrum from 10 women 1.3, 1.1, and 19.7 mg/1, respectively. A good correlation was observed between the values obtained by radioimmunoassay and by single radial immunodiffusion on concentrates of urinary proteins.

Turnover in humans of β2‐microglobulin: the constant chain of HLA‐antigens

Abstract: The turnover of beta 2-microglobulin, the common subunit of the HLA antigens, has been examined in normal subjects and in some patients with kidney disorders, multiple myeloma and rheumatoid arthritis. All patients displayed elevated serum levels of beta 2-microglobulin. The plasma disappearance curve of 125I-beta 2-microglobulin demonstrated that the protein has a rapid turnover (t 1/2 = 2.1 h; range 1.1-2.8 h) in normal persons and in patients with a normal glomerular filtration rate. In patients with kidney disorders the impaired renal filtration prolonged the turnover time and led to elevated serum levels of beta 2-microglobulin. Simultaneous measurements of 125I-beta 2-microglobulin in serum and urine allowed estimations of the beta 2-microglobulin net reabsorption in the renal tubuli. Two patients with renal disease reabsorbed 84% and 89%, respectively, of the beta 2-microglobulin filtered in the glomeruli. In normal persons the net reabsorption is close to 100%. In patients with normal kidney function increased serum levels of beta 2-microglobulin seem to be due to an increased synthetic rate of the protein as the elimination rate is normal. HLA antigen heavy chains in serum are present in smaller amounts than beta 2-microglobulin. The present data, therefore, suggest an imbalanced synthesis of the two chains.

Isolation of the Human Retinol Binding Protein by Affinity Chromatography

Abstract: The human retinol binding protein, which in plasma is bound to thyroxine binding prealbumin, has been isolated in free form from urine of patients with tubular proteinuria and from normal serum. The isolation procedure for urinary retionl binding protein involved gel chromatography and affinity chromatography on a column of prealbumin coupled to Sepharose, whereas the isolation of serum retinol binding protein required three fractionation steps; DEAE-Sephadex chromatography, and affinity chromatography. The retinol binding protein from urine and serum was obtained in a yield of 31% and 42% respectively. The relatively low yield of the urinary protein was explained by the fact that two forms of retinol binding protein were present in the urine, one of which did not bind to prealbumin. The purity of the retinol binding protein isolated from urine and serum was established by the following criteria: immunoelectrophoresis, polyacrylamide gel electrophoresis, amino acid analyses, and sedimentation equilibrium ultracentrifugations. The use of affinity chromatography offers a simple and rapid procedure for the isolation of moderate quantities of highly purified retinol binding protein from urine and serum.

Demonstration in Serum of two Physiological Forms of the Human Retinol Binding Protein

Abstract: . The contents of prealbumin, retinol binding protein, and retinol in normal human serum have been estimated. The amounts of prealbumin were, on average, 6 times larger than those of RBP, that is a two-fold molar excess of prealbumin over RBP. Retinol and RBP were present in about the same molar amounts. Prealbumin occurred in two molecular forms in serum. About half of the prealbumin was bound to RBP (prealbumin-RBP complex) and half was in free form. In spite of the molar excess of prealbumin, small amounts of free RBP were encountered. The free RBP was isolated from normal serum and displayed about the same characteristics as RBP isolated from the prealbumin-RBP complex. Some significant differences were noted however. The free RBP had a lower content of retinol and one amino acid residue less of arginine. The contents of prealbumin, RBP, and retinol were also estimated in the sera of patients subjected to chronic haemodialysis. The amounts of prealbumin and retinol were normal or somewhat low whereas the values for RBP were considerably elevated. The size distribution of RBP and retinol in the serum of one of these patients showed that the amount of free RBP was considerably elevated whereas the amount of the prealbumin-RBP complex was normal. Retinol was apparently associated only with the prealbumin-RBP complex. Various analyses revealed that RBP, isolated in free form from serum, did not bind to prealbumin in contrast to RBP from the prealbumin-RBP complex. It is suggested that the free species of RBP, present in serum, represents a transitory form which has fulfilled its physiological role and will rapidly be degraded by the kidney.

Urinary Immunoglobulin Components in Normal, Tubular, and Glomerular Proteinuria: Quantities and Characteristics of Free Light Chains, IgG, IgA, and Fcγ Fragment.

Abstract: The urinary excretion of free light immunoglobulin chains IgG, IgA, and Fcγ fragment material has been estimated in 12 healthy individuals and 7 subjects with tubular or glomerular proteinuria. Measurements were carried out by immunochemical methods after separation of concentrated urinary immunoglobulin components by gel chromatography. Various components were isolated and their sedimentation constants, Stokes' radii, diffusion coefficients, molecular weights, and frictional ratios were determined.-Twenty-four hour urine volumes from the healthy subjects contained, on average, 3.3 mg of free light chains, 3.0 mg of IgG, approximately 2.0 mg of IgA, and 0.19 mg of Fey fragment Material. Normal urinary IgA included about 90% 11.5 S IgA of molecular weight 370000 and about 10% 7.0 S of molecular Weight 165000.-Patients with tubular proteinuria excreted relatively more of immunoglobulin components of small size than the patients with glomerular proteinuria. In particular, urine from patients with tubular proteinuria contained more free light chains than IgG whereas urine from patients with glomerular proteinuria contained more IgG than free light chains. The excretion of free light chains in the patients with tubular proteinuria was 8 to 33 times the average normal value. The results indicate an excess normal production of light chains assuming that all or most of the free chains originate from de novo synthesis. The relative amounts of urinary 11.5 S and 7.0 S IgA were similar in tubular proteinuria and normal proteinuria, whereas relatively more urinary 7.0 S IgA was found in glomerular proteinuria. This observation and the properties of the two IgA species suggest that the 11.5 S IgA is secretory IgA from the urinary tract and that most or all of the 7.0 S IgA originates from plasma.