Lars Hemmingsen

β2-microglobulin in urine and serum determined by ELIS A technique

A two-site solid-phase enzyme immunoassay for the determination of beta 2-microglobulin in serum and urine is established using polystyrene tubes as solid phase. Horseradish peroxidase-conjugated antihuman beta 2-microglobulin was used as labelled antibody. The technique is based on a general ELISA procedure and can be established without any specific equipment.

Urine profiles and kidney histology after intravenous injection of ionic and nonionic radiologic and magnetic resonance contrast media in normal rats

RATIONALE AND OBJECTIVES Previous studies showed that both high-osmolality and low-osmolality iodinated contrast media cause temporary albuminuria and enzymuria (presence of enzymes in urine) in normal rats. Whether the same is true with ionic high-osmolality and nonionic low-osmolality magnetic resonance (MR) contrast media is unknown. We studied urine profiles and histology after intravenous injection of four types of contrast media in rats with normal kidneys. METHODS Urine profiles were monitored 4, 24, 48, and 72 hr after intravenous injection of saline, diatrizoate, iohexol, gadopentetate dimeglumine, and gadodiamide (4.59 mmol/kg of body weight) in normal rats. Each group included 20 male rats. After sacrifice, both kidneys were removed for examination by light microscopy (LM) and electron microscopy (EM). RESULTS All four contrast agents caused a temporary (< 22 hr) increase in the excretion of albumin (2-5 times) and of cytoplasmic (30-100 times) and brush border (10-100 times) renal enzymes when compared with saline. The degree of albuminuria correlated well (r = 0.90) with the osmolality of the injected media, whereas the increased level of enzymuria was unrelated to the osmolality. No major differences in the enzymuric effects of the four agents were noted. LM revealed vacuoles in all kidneys exposed to radiologic contrast media but not in kidneys exposed to MR contrast media or saline. Slight vacuolation was revealed by EM after the use of MR contrast media, and significant vacuolation was evident via EM after the use of radiologic contrast media. No difference between ionic and nonionic media within each drug group was detected by either LM or EM. CONCLUSIONS Transient renal effects are induced by both ionic and nonionic high-osmolality and low-osmolality radiologic and MR contrast media in normal rats. Both osmotic (e.g., albuminuria) and chemotoxic (e.g., enzymuria) mechanisms seem to be involved. From a morphologic point of view, the chemotoxic mechanisms seem to be of major importance.

DISC ELECTROPHORESIS OF AQUEOUS HUMOUR

Previous Electrophoretic Studies of Normal Aqueous Humour Electrophoretic separation of proteins in aqueous humour from animals was first attempted in 1948 by won Sallmann and Moore, who used free electrophoresis by the method af Tiselius. This method requires about 2 ml of fluid, and it was therefore not possible to study the aqueous from just one animal. Their studies were performed on a pool of aqueous humour from 80 rabbits, and also on aqueous humour from horses and cattle. By this method it was possible to separate the following fractions in normal aqueous: pre-albumin, albumin, alpha, beta and gamma globulins, although not all of these fractions were present in each of the three materials studied. With the advent of paper electrophoresis it became possible to obtain a better separation of the individual protein fractions, and smaller amounts of fluid were required. In 1951, Witmer published the first results of paper electrophoresis performed on samples of pathological human aqueous, and since then he has performed a series of such studies. However, only a few electrophoretic analyses of normal aqueous humour have been reported in the literature. Wunderly and Cagianut (1952) studied electrophoretically five pools of aqueous humour from 13 normal, mainly amblyopic eyes. They succeeded in separating the proteins into albumin, alpha, beta and gamma globulins (table 1). In paper electrophoresis of a pool of aqueous humour from 11 normal eyes, Esser et al. (1954) were able further to separate the alpha globulin fraction into alphal and alpha, and found, in addition, pre-albumin (table 2). In electrophoretic analysis of a pool of aqueous humor from 11 eyes from cadavers, the

Diabetic retinopathy related to degree of albuminuria and tubular (low molecular weight) proteinuria in insulin‐dependent (Type I) diabetes mellitus

Abstract The urinary excretion of albumin (a marker of glomerular damage) and retinol binding protein (a low molecular weight protein marker of tubular dysfunction) was determined by sensitive immunochemical methods in 110 insulin‐dependent (Type I) diabetic patients. We observed a statistically significant correlation between the urinary excretion levels of both proteins, in particular albumin, and the degree of retinopathy. The incidence of macroalbuminuria and tubular proteinuria was significantly higher in patients with manifest background retinopathy and proliferative retinopathy as compared to patients with no or slight retinopathy. The duration of diabetes was significantly correlated to the degree of retinopathy, but not to the urinary excretion of albumin and retinol binding protein.

URINE PROFILES AND KIDNEY HISTOLOGIC FINDINGS AFTER INTRAVENOUS INJECTION OF MANNITOL AND IOHEXOL IN THE DEGENERATION PHASE OF GENTAMICIN NEPHROPATHY IN RATS

RATIONALE AND OBJECTIVES.Previous studies have shown that iodinated contrast media may cause further renal dysfunction in tubulointerstitial nephropathy induced by gentamicin. The current investigation was undertaken to study whether the dysfunction after intravenous injection of a lowosmolar contrast medium is due to a chemotoxic and/or an osmotic effect. METHODS.Urine profiles were followed for 3 or 9 days after intravenous injection of saline, mannitol, and varying dosages of iohexol (1, 2.5, 5, and 10 mL/kg body weight (BW); 350 mg I/mL) in 60 rats, in which intramuscular injection of 40 mg/kg BW gentamicin had been administered daily nine times. A seventh group of 10 rats was given 20 mg/kg BW gentamicin and 5 mL/kg BW of 350 mg I/mL iohexol. Another 10 rats injected with saline served as controls. RESULTS.Both mannitol and iohexol increased the excretion of albumin and the enzyme N-acetyl-B-D-glucosamidase (NAG) temporarily; the effect was independent of the dose of Iohexol. There was a dose-dependent effect on the transientincrease in excretion of the enzymes lactate dehydrogenase (LDH), gamma glutamyltransferase (GGT), and alkaline phosphatase (ALK); mannitol did not increase the excretion of these enzymes. In the group given 20 mg/kg BW gentamicin, only the dose-dependent effects of iohexol were seen. Neither various plasma components nor light/electron microscopy showed any changes that could solely be related to the contrast medium. CONCLUSIONS.Iohexol produces transient renal effects in gentamicin nephropathy, which may be due to both chemotoxic and osmotic mechanisms.

Do contrast media aggravate Fanconi's syndrome in rats? A comparison of diatrizoate, iohexol, and ioxilan.

Thomsen HS, Dorph S, Mygind T, Nielsen H, Rygaard H, Larsen S, Skaarup P, Hemmingsen L, Holm J. Do contrast media aggravate Fanconis syndrome in rats? A comparison of diatrizoate, iohexol, and ioxilan. Invest Radiol 1988;23(Suppl 1):S164‐S167. Urine profiles (albumin, glucose, N‐acetyl‐&bgr;‐D‐glucosaminidase [NAG], lactate dehydrogenase [LDH], L‐&ggr;‐glutamyltransferase [GGT], sodium, and phosphate) were followed for seven days after intravenous (IV) administration of either diatrizoate, iohexol, ioxilan, or saline in 24 Wistar rats with a tubular dysfunction induced by IV sodium maleate. Ioxilan and saline had a similar effect on albumin excretion, iohexol had an intermediate effect, and diatrizoate increased it significantly from day 2 to day 7. Glucosuria was significantly greater after diatrizoate than after the nonionic contrast media (CM) or saline. Diatrizoate delayed normalization of enzymuria, whereas iohexol and ioxilan did not. None of the CM affected urinary sodium or phosphate excretion. It is concluded that Fanconis syndrome is significantly aggravated only by diatrizoate.

Nephropathy induced by intramuscularly administered glycerol and contrast media in rats. A comparison between diatrizoate, iohexol and ioxilan.

Urine profiles (albumin, glucose, NAG, LDH, GGT, sodium, and phosphate) were followed for 14 days after intravenous injection of either diatrizoate, iohexol, ioxilan, or saline in 24 Wistar rats with a glomerular and tubular dysfunction induced by intramuscularly (i.m.) administered glycerol. Another 6 rats exposed to neither glycerol nor contrast media served as controls. The effect of ioxilan and saline on the albumin excretion was similar, whereas diatrizoate and iohexol increased it significantly. The contrast media had no further inhibitory effect on the reabsorption of glucose. Iohexol caused significantly increased excretion of all three enzymes, ioxilan of NAG and LDH, whereas diatrizoate only increased the excretion of LDH. The sodium excretion was further increased by ioxilan and diatrizoate, whereas none of the contrast media affected the phosphaturia. Both ioxilan and iohexol caused a round cell response around the tubules shown by light microscopy whereas diatrizoate caused no further changes. It is concluded that diatrizoate and iohexol increase glomerular dysfunction induced by glycerol i.m.; all three contrast media cause some further increase in the tubular dysfunction. Neither diatrizoate, iohexol nor ioxilan prolong nephropathy induced by glycerol i.m. determined by the chemical analyses. The histologic finding indicates a direct toxic effect of non-ionic low osmolar contrast media in this animal model of nephropathy.

Nephrotoxicity of cyclosporin A and contrast media. A comparison between diatrizoate and iohexol in rats.

Urine profiles (albumin, glucose, NAG, LDH, GGT and sodium) were followed for 22 h or 8 days after intravenous injection of diatrizoate, iohexol or saline in 30 adult Wistar rats in which nephrotoxicity was induced by daily peroral administration of 25 mg/kg body weight cyclosporin A over a 14-day period. Another 10 rats which had the vehicle of the cyclosporin A solution (placebo) and saline injected intravenously served as controls. The effect of iohexol and saline on the albumin excretion was similar, whereas diatrizoate increased it significantly. Both contrast media caused significantly increased excretion of all three enzymes. The contrast media had no effect on the excretion of glucose and sodium. Except for the fact that the excretion of NAG was significantly higher following iohexol than following diatrizoate 24 to 46 h after injection no significant differences between the two media were found from 24 h after injection among the rats given cyclosporin A. No contrast medium related changes were found by light microscopy of the kidneys. Neither iohexol nor diatrizoate potentiate acute cyclosporin A nephrotoxcity.

Urine profiles following intravenous diatrizoate, iohexol, or ioxilan in rats.

Thomsen HS, Dorph S, Mygind T, Hemmingsen L, Holm J, Larsen S, Nielsen H, Rygaard H, Skaarup P. Urine profiles following intravenous diatrizoate, iohexol, or ioxilan in rats. Invest Radiol 1988;23(Suppl 1):S168‐S170. The effects of intravenous diatrizoate, iohexol, ioxilan, or saline on albumin, glucose, sodium and the enzymes N‐acetyl‐&bgr;‐D‐glucosaminidase (NAG), lactate dehydrogenase (LDH), and L‐&ggr;‐glutamyltransferase (GGT) in the urine of 24 normal Wistar rats were followed for seven days. During the first two hours after administration of diatrizoate, all profile components changed markedly; the albumin excretion was significantly greater than following ioxilan and iohexol; glucose, LDH, and GGT excretions were significantly greater than following ioxilan. Iohexol and ioxilan caused a higher excretion of albumin, LDH, and GGT than saline. Iohexol also increased glucose and sodium levels. Glucose and GGT were significantly higher following iohexol than following ioxilan. Both high osmolar and low osmolar contrast media may cause temporary glomerular and tubular damage. Urine profile components are affected most by diatrizoate, less by iohexol, and least by ioxilan.

Urine Profiles and Kidney Histology Following Intravenous Diatrizoate and Iohexol in the Degeneration Phase of Gentamicin Nephropathy in Rats Effects on Urine and Serum Profiles

Urine chemical profiles were followed for three or nine days after intravenous injection of diatrizoate, iohexol, or saline in 30 rats, where a tubulointerstitial nephropathy was induced by gentamicin given over an eight-day period. Another ten rats injected with saline served as controls. Compared to injection of saline, both iohexol and diatrizoate induced dysfunction. The excretion of the cytoplasmic enzyme lactate dehydrogenase was significantly greater following iohexol than following diatrizoate. No significant differences between the two media were shown by the various serum components examined. Among the gentamicin-treated rats, light microscopy showed prolonged occurrence of tubular necrosis and a more intensive round cell infiltration following iohexol than following diatrizoate and saline. Both contrast media induced further temporary renal dysfunction in rats with gentamicin nephropathy; iohexol induced more morphologic changes than diatrizoate.