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Biomedical subjects

U Ravnskov

Publications and source records attributed to U Ravnskov.

At least 91 records · Page 5Linked to original sources
PubMed1976

alpha1-Microglobulin, a new low molecular weight plasma protein.

A new low molecular weight protein was purified from the urine of uraemic patients. The protein was found to be glycoprotein with a molecular weight of 31 500, determined by SDS-polyacrylamide gel electrophoresis, and a carbohydrate content of 19%. It was electrophoretically heterogenous and migrated in the slow alpha1-region. The mean serum level in 20 apparently healthy individuals was 32+/-10 mg/1. The serum level was normal in 5 patients with severe reduction of plasma protein synthesis caused by cirrhosis of the liver but elevated in patients with a decreased glomerular filtration rate. The mean urinary excretion in 5 healthy individuals was 1.3 mg/24 h. Increased excretion was seen in 10 patients with varying degrees of uraemia.

Amino Acids↗
PubMed1976

Low molecular weight proteinuria and slight hyperlipoproteinemia in three mentally retarded brothers.

Mental retardation in combination with proteinuria and a slight hyperlipoproteinemia was found in three brothers. The increased urinary protein excretion was dominated by albumin and the low molecular weight proteins retinol-binding protein (RBP) and beta2-microglobulin, indicating the presence of proximal tubular dysfunction. However, there was no glucosuria, phosphaturia or amino aciduria and the renal concentrating and acidification capacities were normal. A kidney biopsy in one of the patients revealed morphologic evidence of glomerular damage but a normal tubular structure. A mild hyper-beta-lipoproteinemia was found in the patients but not in their healthy siblings. The cause of this syndrome, hitherto not described, is unknown.

Adolescent↗
PubMed1976

Renal handling of Zn-alpha2-glycoprotein as compared with that of albumin and the retinol-binding protein.

An unusual electrophoretic pattern of the urine from a patient with malignant lymphoma was observed. One of the major proteins, identified Zn-alpha2-glycoprotein (Zn-alpha2), was isolated from the urine and partly characterized. The Stokes radius was found to be 3.24 nm and the molecular weight, determined by sodium dodecyl sulfate polyacrylamide electrophoresis, 42,000. The plasma level in healthy individuals was 39 +/- 7 (SD) mg/liter. In 12 of 25 healthy individuals, Zn-alpha2 was measurable in the urine and was found to be 1.0 +/- 1.1 mg/liter. In 23 patients with chronic glomerulonephritis (CGN), in 9 with proximal tubular dysfunction (PTD), in 23 with various renal diseases (VRD), and in 10 with malignant lymphoma, the plasma level and the urinary excretion were compared with those of albumin (mol wt 67,000) and of the retinol-binding protein (RBP, mol wt 21,000). A close correlation was found between the urine-to-plasma (U/P) ratios of Zn-alpha2 and albumin in the patients with CGN, whereas in the PTD patients the U/P ratios of Zn-alpha2 and RBP were correlated. No significant renal arteriovenous difference in Zn-alpha2 could be demonstrated. The Zn-alpha2 excretion was increased also in two patients with malignant lymphoma and proteinuria of a tubular pattern. The plasma Zn-alpha2 varied inversely with the glomerular filtration rate in the patients with renal disease, but was normal in those with malignant lymphoma. The results are consistent with the assumption of a sieving coefficient of Zn-alpha2, substantially exceeding that of albumin, but notably lower than that of smaller low-molecular-weight proteins. An increased excretion of Zn-alpha2 may be due to increased glomerular permeability as well as to defective proximal tubular reabsorption.

Adult↗
PubMed1976

Experimental porcine nephropathy: changes of renal function and structure perorally induced by crystalline ochratoxin A.

Nine pigs were fed crystalline ochratoxin A in amounts corresponding to a feed level of 1 mg per kg for 3 months. The only observable lesion developed was a kidney damage, identical to the naturally occurring porcine nephropathy. The changes of renal function was characterized by impairment of proximal tubular function, indicated by a decrease of the ratio TmPAH/CIn, of the ability to concentrate urine, and by an increased urinary excretion of glucose. The decrease of the ratio TmPAH/CIn is correlated with time of exposure to ochratoxin A. The changes of renal structure were characterized by degeneration of the proximal tubules, leading to tubular atrophy accompanied by interstitial fibrosis. At the end of the experiment the kidney, liver, adipose and muscular tissue of the slaughtered pigs contained sizable amounts of ochratoxin A residues. As the pigs would have passed the meat inspection this represents a possible health problem. The changes observed in this study are identical to those observed by feeding to pigs grains naturally contaminated with ochratoxin A.

Adipose Tissue↗
PubMed1975

Renal handling of human beta2-microglobulin in the rat: the importance of sham-operation.

The plasma disappearance rates of human beta2-microglobulin and (hydroxy-methyl-C14)-inulin was measured in unoperated, sham-operated, ureter-ligated and nephrectomised rats. Judging from the C14-activity curves in ureter-ligated and nephrectomised rats a substantial glomerular filtration continued after obstruction of the urine flow. Almost 90% of the injected protein had disappeared from plasma 120 min after injection into nephrectomised rats indicating a considerable extra-renal elimination and invalidating attempts to evaluate different renal mechanisms of elimination before and after ureter-ligation. Sham-operation induced an increase of the plasma disappearance of both beta2-microglobulin and inulin. The latter phenomenon may explain earlier findings of similarity between the disappearance curves of low molecular weight proteins in unoperated and ureter-ligated animals and stresses the importance of using sham-operated animals as controls.

Animals↗
PubMed1975

Proteinuria in pigs with experimentally induced renal damage.

Proteinuria was studied experimentally in pigs with renal damage induced by maleic acid, potassium dichromate and by 5/6 nephrectomy. The methods used were: analysis of total protein, immunochemical quantitation of a porcine low molecular weight (alpha-PLMW) protein, agarose gel electrophoresis, and gel chromatography of concentrated urine samples. The urinary clearance of the alpha-PLMW protein in normal pigs was considerably higher than LMW protein clearance in normal man. No increase was seen after surgery. The induction of proximal tubular damage resulted in an increased excretion of, above all, high molecular weight proteins (greater than or equal to albumin) but also of low molecular weight proteins. The highest increase in alpha-PLMW clearance was seen immediately after 5/6 nephrectomy, and the increased alpha-PLMW excretion in pigs with proximal tubular dysfunction was better correlated to creatinine clearance than to the degree of phosphaturia or glucosuria. The results suggest different renal handling of plasma proteins in pigs and humans.

Animals↗
PubMed1975

Low molecular weight proteinuria in association with paroxysmal myoglobinuria.

A patient with paroxysmal myoglobinuria presented with low molecular weight (LMW) proteinuria in association with an episode of exertional myoglobinuria. Since no signs of acute renal failure were present, the cause was probably competition between myoglobin and other LMW proteins for proximal tubular reabsorption. Agarose gel electrophoresis was found to be an excellent method for the investigation of myoglobinuria since this technique not only allowed the separation of myoglobin from hemoglobin but also myoglobin from metmyoglobin.

Adult↗