Knut-Jan Andersen

Effects of iodinated x-ray contrast media on renal epithelial cells in culture.

RATIONALE AND OBJECTIVES.To study cellular mechanisms that cause contrast media nephropathy, an in vitro system for proximal and distal tubular cells has been established to evaluate the influence of x-ray contrast media on tubular function. METHODS.Confluent cell cultures of the two renal cell lines, proximal tubule (LLC-PK,) and distal tubule (MDCK), were exposed for 20 hours to 0 to 100 mg iodine/mL of the ionic monomer metrizoate, the ionic dimer ioxaglate, and the nonionic monomer iohexol. Toxicity was assessed by electron microscopy, cell viability, and biochemical assays of brush-border and lysosomal marker enzymes. RESULTS.The results demonstrated a concentration-dependent toxic effect from the contrast media on cellular appearance consisting of an increased vacuolization and on the activity of brush-border and lysosomal marker enzymes in cells and in culture media. CONCLUSION.The results, in which the nonionic x-ray contrast media iohexol appeared to be less toxic than the ionic x-ray contrast media investigated, demonstrated that defined renal cells in culture are valuable tools in studies regarding renal toxicity of x-ray contrast media.

Effect of dietary copper on the hepatic concentration and subcellular distribution of copper and zinc in the rainbow trout (Salmo gairdneri)

Abstract Feeding trials were conducted with six groups of rainbow trout (mean initial weight of 35 g) using purified diets with an estimated gross energy of 1442 kJ 100 g and copper contents ranging from 3.5 to 1000 mg Cu/kg diet. With the exception of groups 1 and 2 (given 102 and 194 mg Cu/kg), which showed an atypical growth response, the weight gain and feed conversion were reduced with increasing levels of Cu in the diet. No gross pathologies and very low mortalities were noted even in the group receiving the highest dietary copper level. Copper and zinc were determined in freeze-dried samples and in subcellular fractions from individual trout livers using atomic absorption spectrophotometry. A linear relationship was observed between liver copper concentration and copper provided in the diet. Copper intake had no effect on hepatic zinc concentration. Increased dietary copper also gave increased copper levels in whole fish but the concentration factor was much lower than in the liver. The relative retention of copper given at levels above 100 mg Cu/kg dry diet was low and was estimated to be 1.3%. Subcellular fractionation studies demonstrated that 43–67% and 36–49%, respectively, of hepatic copper and zinc were sedimented with the fractions nuclei, mitochondria and lysosomes. Increased dietary levels of copper had apparently no effect on the subcellular distribution of zinc except at the highest level (group 6) where an increase in zinc recovered in the nuclear fraction was observed.

Subcellular distribution of major and minor elements in unexposed molluscs in Western Norway—III. The distribution and binding of cadmium, zinc, copper, magnesium, manganese, iron and lead in the kidney and the digestive system of the horse mussel Modiolus modiolus

Abstract 1. 1. The subcellular distribution of Cd, Zn, Cu, Mg, Mn, Fe and Pb has been studied in the kidney and the digestive system of the horse mussel M. modiolus . Zinc, although principally paniculate bound, had a distribution in the kidney different from the digestive system. The other elements showed a similar distribution pattern in the two organ systems. 2. 2. Cd was principally recovered in the cytosols. During gel filtration on Sephadex G-75, more than 50% of the Cd from the kidney cytosol was recovered in the macromolecular fraction (void volume). In addition, the kidney contained two Cd-binders with mol. wts of 18,000 and 28,000 respectively. The digestive system contained one Cd-binder with a mol. wt of 17,000. This binder accounts for about 60–70% of total cytosol Cd. 3. 3. It is concluded that a common pattern for distribution and element handling could not be seen within the tissues examined.

Fluorometric determination of DNA in fixed tissue using ethidium bromide

Abstract The measurement of DNA in tissue samples fixed in ethanol/acetic acid is described. Small, fixed tissue samples are digested by warm alkaline treatment followed by neutralization with HCl, and DNA is determined by complex formation with the dye ethidium bromide (EB). When standard DNA from calf thymus was treated similarly, a hyperchromicity of 8–12% and a reduction in fluorescence intensity of the EB-DNA complex to 55% was observed. The NaOH concentration (0.5–2.0 mol/liter) or the temperature (50–60°C) used for the digestion of tissue, as well as subsequent ribonuclease or protease treatment had no effect on the observed tissue DNA concentrations.

Subcellular distribution of major and minor elements in unexposed molluscs in Western Norway—I. The distribution and binding of cadmium, zinc and copper in the liver and the digestive system of the oyster Ostrea edulis

Abstract 1. 1. The subcellular distribution of Cd, Zn and Cu has been studied in the liver and the digestive system of the oyster O. edulis. The relative distribution amongst the particulate fractions was different in the liver and in the digestive system while there were no profound differences in the recoveries of elements in the cytosol-fractions. 2. 2. The major part of cytosol Cd from both tissues were recovered in the low molecular weight fractions (mol. wt 3. 3. It is concluded that Cd, Zn and Cu are bound and accumulated differently, and that a general principle of element handling does not seem to be present in the tissues examined.

A routine method for the determination of aluminium in human tissue samples using standard addition and graphite furnace atomic absorption spectrophotometry

Abstract Aluminium in human tissue samples has been determined by atomic absorption spectrophotometry using the nitrous oxide-acetylene flame and the graphite furnace atomizer. The two methods are compared. Flameless atomic absorption was found superior when standard addition was applied. A routine method is thus described in detail in which aluminium levels down to 0.1 mg/kg of freeze-dried tissue and 0.01 mg/liter of serum can be determined.

Trace elements intake in the Faroe Islands III. Element concentrations in human organs in populations from Bergen (Norway) and the Faroe Islands

Flameless as well as flame atomic absorption spectrophotometry were used for the analysis of six elements (calcium, iron, zinc, selenium, cadmium and mercury) in human organs (liver, kidney cortex and medulla, heart, pancreas and spleen) from 13 bodies from Bergen and 10 from the Faroe Islands. Samples were taken at autopsy and the organs selected were without pathological signs. All patients were born between 1899 and 1923. Element concentrations in the organs studied were comparable to previous studies, except for high mercury and selenium values in the liver, the kidney cortex and medulla of subjects from the Faroe Islands. The high mercury and selenium values may be explained by the high consumption of pilot whales by the Faroe Islands population.

A study on the digestion of human muscle biopsies for trace metal analysis using an organic tissue solubilizer.

Abstract A commercially available tissue solubilizer, based on tetraalkyl-ammonium hydroxide in toluene, has been compared with conventional digestion producers in order to determine the minimum amount of tissue needed for the determination of trace elements such as Al, Cd, Cu, and Mn in human biopsy material using flameless atomic absorption spectrophotometry. The solubilizer can be recommended for digestion of biopsy samples in order to determine Cu, Cd, and Mn, but not Al.

The Effect of Proteolytic Enzymes on the Vitamin B12-binding Proteins of Human Gastric Juice and Saliva

Pepsin had no effect on the vitamin B12 binder in human saliva (R-binder), while trypsin was found to reduce the apparent molecular weight of the R-binder and to release vitamin B12 from the R-B12complex of human saliva and human gastric juice (HGJ). Trypsin had no effect on the molecular weight and biological activity of intrinsic factor (IF) in HGJ, as demonstrated by gel filtration on Sephadex G-150 and the uptake of IF-B12 by guinea pig intestinal brush borders. An extract of purified guinea pig intestinal lysosomes was also without effect on the molecular weight and the biological activity of IF but was found to release vitamin B12 from the R-B12 complex. The results support the observation that the external pancreatic secretion corrects malabsorption of vitamin B12 by an effect on the non-IF protein in the intestinal juice. Moreover, the results indicate that lysosomal enzymes are not involved in the intestinal absorption of vitamin B12.

Enzyme Activities in the Duodenal Mucosa in Duodenal Ulcer Patients

The mucosal enzyme activities of 11 marker enzymes from the brush border, basolateral membrane, and lysosomes of 45 patients with an active duodenal ulcer (DU) were determined by analysis of homogenized biopsy specimens obtained from the duodenal bulb and descending duodenum at endoscopy. They were compared with activities measured in 22 controls. In the duodenal bulb lactase (p less than 0.005), neutral-alpha-glucosidase (p less than 0.0005), and monoamine oxidase (p less than 0.0005) were significantly decreased in DU patients. In the descending duodenum all the brush border enzymes except sucrase were significantly decreased when compared with controls. DU patients with inflammation in the biopsy specimens from the duodenal bulb had decreased levels of lactase (p less than 0.05), sucrase (p less than 0.05), neutral-alpha-glucosidase (p less than 0.05), leucyl-beta-naphthylamidase (p less than 0.05), and acid phosphatases (p less than 0.05) when compared with DU patients with normal histology in this region. In the descending duodenum the activities of leucyl-beta-naphthylamidase (p less than 0.05) were decreased in patients with inflammation compared with those without such histologic changes. DU patients who had taken antacids before the investigation had decreased activities of lactase (p less than 0.05) in the descending duodenum when compared with those who had not taken antacids. Activities of lactase (p less than 0.005), sucrase (p less than 0.005), neutral-alpha-glucosidase (p less than 0.05), and acid beta-glucuronidase (p less than 0.0005) in the descending duodenum were significantly lower in smokers than in non-smokers with active DU.