BACKGROUND/AIMS:Previous reports state that there is absorption of bismuth through active peptic ulcers. It was therefore of interest to investigate the extent of absorption in patients at the ulcer and post-ulcer stages.METHODOLOGY:Twenty H. pylori-positive patients with gastroscopically verified gastric or duodenal ulcers were randomly allocated to ingest 3000 mg bismuth subnitrate (BSN) (10 patients) or 480 mg colloidal bismuth subcitrate (CBS) (10 patients). Bismuth serum concentration in 12 samples drawn during the first 4 hours after drug intake was analyzed and the area under the curve (Bi-AUC) was calculated. Anti-H. pylori therapy with amoxicillin and lanzoprazole eradicated H. pylori in 10 patients and healed the ulcers in all patients 4 weeks after therapy ended, then the bismuth absorption test was repeated.RESULTS:There was no significant difference between ulcer- and post-ulcer Bi-AUC for patients receiving BSN or for patients receiving CBS. On a molar basis, CBS gave a 17.4-fold greater absorption of bismuth compared to BSN.CONCLUSIONS:The presence of an active ulcer does not significantly influence the absorption of bismuth from CBS or BSN.

The established renal epithelial cell line LLC-PK1 (proximal tubule) started to form multicellular spheroids within 24 h when grown in agar overlay culture. The spheroids, average diameter 100 to 350 microns, were free-floating with a butterfly-like structure due to the formation of several hollow microspheres. The microspheres were lined with polarized epithelial cells that had an abundance of microvilli protruding into the external medium and a well developed vacuolar apparatus, including coated pits, endocytotic vacuoles, and lysosomes. The microspheres were sealed between lumen and the surrounding medium by tight junctions and fluctuated in size due to fluid being transported in an apical-to-basal direction. Vasopressin was found to stimulate this transport, whereas the addition of ouabain or HgCl2 inhibited both spheroid growth and fluctuation in size with time. Biochemical assays of brush-border and lysosomal marker enzymes demonstrated an increase in enzyme activity during spheroid formation and growth. The most dramatic changes were observed for dipeptidyl peptidase IV (two- to threefold after 1 d and 53.5-fold after 15 d), reflecting the cellular polarization and brush-border formation during spheroid formation. When the typical lysosomal enzymes were compared, the activity of peptide bond splitting enzymes increased earlier than others. In conclusion, LLC-PK1 spheroids capable of forming microspheres represent an in vitro manifestation of specialized epithelial properties maintained in cell culture, thus providing a tool for studying renal physiologic mechanisms at a cellular level.

Proximal and distal tubular cells in culture have been exposed to various roentgen contrast media (CM) at concentrations of 0 to 100 mg I/ml for 22 hours to study cellular mechanisms that may be involved in CM-induced nephropathy. The effects on cell morphology were assessed by electron microscopy and cell viability was evaluated. Levels of brush border and lysosomal marker enzymes in the culture medium were assayed biochemically.Morphological examination showed that CM induced a concentration-dependent formation of large cytoplasmic vacuoles in both cell lines. Cellular damage was observed more frequently after exposure to low-osmolal rather than the iso-osmolal CM iodixanol; the low-osmolal CM causing more cell death and inhibiting cellular growth to a greater degree than did iodixanol.In cultures of both cell lines the CM produced a concentration-dependent increase in brush border marker enzyme activity. While an increase in lysosomal enzyme activity was seen at low concentrations, a decrease in activity occurred at high concentrations.Earlier investigations have demonstrated that the nonionic CM have less pronounced effects on the cell lines studied than ionic CM. The results presented here indicate that the effects of the iso-osmolal nonionic CM (iodixanol) on both the investigated cell lines are less marked than those of the low-osmolal nonionic CM investigated.

Production of proteolytic enzymes is important for the invasive properties of malignant tumours. In this series of 43 cases of various non-neoplastic and neoplastic thyroid lesions, the activity of dipeptidyl peptidase I and dipeptidyl peptidase IV was increased in papillary carcinomas. In addition, cathepsin B and cathepsin L were markedly elevated in 2 of 3 follicular carcinomas, and tryptase, which is a marker of mast cells, was also significantly elevated in follicular carcinomas. Our results indicate that proteolytic proteins are important in thyroid carcinomas, and in addition there seem to be some differences between papillary and follicular tumours. Larger studies are needed to confirm these findings.

The rat glial cell line C6 has been used to assess the toxicity of two different iodine-based X-ray contrast media: the non-ionic dimer iodixanol and the non-ionic monomer iohexol. The cells were exposed to increasing concentrations (0-75mg iodine/ml) during exponential growth (up to eight days). A dose-dependent inhibition of cell growth was observed when iohexol was added to the culture medium, but not when iodixanol was added. While iohexol had a profound, long lasting effect on cell viability, iodixanol, after an initial adverse impact, had no effect. Iohexol and iodixanol both caused increased lysosomal peptidase activity, as shown for dipeptidyl peptidase, but had no effect on other lysosomal enzymes, such as acid beta-galactosidase. Electron microscopy revealed no changes in the cellular ultrastructure after exposure to iodixanol. In contrast, there was extensive vacuolisation in the cells exposed to iohexol, including a significantly increased number of autophagocytic vacuoles. It would appear that iodixanol has only minor effects on glial cells in culture, compared to those induced by iohexol.

Conference Abstract| March 01 1993 Enzyme Release and Cellular Morphology of Renal Epithelial Cells following X-Ray Contrast Media Exposure K-J Andersen; K-J Andersen 1Division of Clinical Cell Biology, University of Bergen, Medical Department A, Haukeland Sykehus, N-5021 Bergen, Norway Search for other works by this author on: This Site PubMed Google Scholar EI Christensen; EI Christensen 2Department of Cell Biology, Institute of Anatomy, University of Aarhus, DK-8000 Aarhus C, Denmark Search for other works by this author on: This Site PubMed Google Scholar H Vik H Vik 3Medical Department, Nycomed AS, P.O. Box 4220 Torshov, N-0401 Oslo 4, Norway Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (1993) 84 (s28): 32P. https://doi.org/10.1042/cs084032Pa Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation K-J Andersen, EI Christensen, H Vik; Enzyme Release and Cellular Morphology of Renal Epithelial Cells following X-Ray Contrast Media Exposure. Clin Sci (Lond) 1 March 1993; 84 (s28): 32P. doi: https://doi.org/10.1042/cs084032Pa Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 1993 The Biochemical Society and the Medical Research Society1993 Article PDF first page preview Close Modal You do not currently have access to this content.

The tissue culture of multicellular spheroids from the renal epithelial cell line LLC-PK1 (proximal tubule) is described. This represents a biological system of intermediate complexity between renal tissue in vivo and simple monolayer cultures. The multicellular structures, which show many similarities to kidney tubules in vivo, including a vectorial water transport, should prove useful for studying the potential nephrotoxicity of drugs and chemicals in vitro.In addition, the propagation of renal epithelial cells as multicellular spheroids in serum-free culture may provide information on the release of specific biological parameters, which may be suppressed or masked in serum-supplemented media.

The two renal cell lines, MDCK (distal tubule) and LLC-PK1 (proximal tubule), have been used for toxicity testing of three different X-ray contrast media: the ionic monomer Isopaque, the ionic dimer Hexabrix and the non-ionic monomer Omnipaque. The cells were grown to confluency in monolayer cultures in a chemically-defined serum-free medium before the contrast media were added, to give final concentrations corresponding to 0–100mg iodine/ml. Toxicity was assessed by cell viability and by biochemical assays of marker enzymes. The results demonstrate a concentration-dependent toxic effect from the contrast media on cellular appearance, and on the activity of brush border and lysosomal enzymes. The non-ionic X-ray contrast media appeared to be less toxic than the ionic contrast media investigated.

1. Receptor-mediated endocytosis of mannose-terminated glycoproteins in rat liver endothelial cells has been followed by means of subcellular fractionation and by immunocytochemical labelling of ultrathin cryosections after intravenous injection of ovalbumin. For subcellular-fractionation studies the ligand was labelled with 125-tyramine-cellobiose adduct, which leads to labelled degradation products being trapped intracellularly in the organelle where the degradation takes place. 2. Isopycnic centrifugation in sucrose gradients of a whole liver homogenate showed that the ligand is sequentially associated with three organelles with increasing buoyant densities. The ligand was, 1 min after injection, recovered in a light, slowly sedimenting vesicle and subsequently (6 min) in larger endosomes. After 24 min the ligand was recovered in dense organelles, where also acid-soluble degradation products accumulated. 3. Immunocytochemical labelling of ultrathin cryosections showed that the ligand appeared rapidly after internalization in coated vesicles and subsequently in two larger types of endosomes. In the 'early' endosomes (1 min after injection) the labelling was seen closely associated with the membrane of the vesicle; after 6 min the ligand was evenly distributed in the lumen. At 24 min after injection the ligand was found in the lysosomes. 4. A bimodal distribution of endothelial cell lysosomes with different buoyant densities was revealed by centrifugation in iso-osmotic Nycodenz gradients, suggesting that two types of lysosomes are involved in the degradation of mannose-terminated glycoproteins in liver endothelial cells. Two populations of lysosomes were also revealed by sucrose-density-gradient centrifugation after injection of large amounts of yeast invertase. 5. In conclusion, ovalbumin is transferred rapidly through three endosomal compartments before delivering to the lysosomes. The degradation seems to take place in two populations of lysosomes.

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.

The subcellular distribution of dipeptidyl peptidase II (DPP II) in the rat kidney cortex, as determined by subfractionation of the mitochondrial/lysosomal fraction by rate sedimentation, indicated that this enzyme is mainly associated with the large, fast sedimenting lysosomes (protein droplets). The small lysosomes, on the other hand, displayed considerable size heterogeneity as indicated by the broad distribution of DPP II; cathepsin B, and a tripeptidyl peptidase active on Gly-Pro-Met-2-naphthylamide at pH 4 (TPP 4). Cathepsin D and N-acetyl-beta-D-glucosaminidase were limited primarily to the slower-sedimenting, small lysosomes. Equilibrium banding in sucrose gradients of the two main DPP II-containing lysosomal populations showed that the large lysosomes banded at a density of 1.235-1.24 g/ml while small lysosomes banded at three densities: 1.11-1.15 g/ml (lysosomal fragments), 1.20 g/ml (light lysosomes), and 1.235 g/ml (dense lysosomes). Identical distribution pattern were obtained for DPP II using either Lys-Ala-7-(4-methyl)coumarylamide or Gly-Pro-2-naphthylamide as the substrate at pH 5.5 and 5.0, respectively. Notably, DPP II and TPP 4, and cathepsin B as well, gave banding densities and distributions that were consistent with a lysosomal localization. Since triplets of the Gly-Pro-X-type released by the TPP 4 are ideal substrates for DPP II, the integrated action of tripeptidyl and dipeptidyl peptidases could make a novel contribution to the renal depolymerization and reabsorption of polypeptides, in particular the proline-rich, collagen-derived sequences that possess repeating-triplet primary structures.

1.1. Experimental proteinuria (262.9mg protein/24hr urine) was induced in rats by repeated intraperitoneal injections of BSA.2.2. Hypertrophy of the kidney cortex was significant 8 days after the start of the BSA injections, and the activities of lysosomal enzymes in kidney cortex and urine were significantly higher in proteinuric compared to nonproteinuric rats.3.3. Lysosome populations in the kidney cortex were examined by rate sedimentation of the homogenate and by rate zonal and isopycnic centrifugation of the lysosome-rich ML fraction.4.4. The activity of lysosomal enzymes in the kidney cortex increased slightly, essentialy in the large, fragile lysosomes mainly recovered from the proximal tubule.5.5. Proteinuria induced a shift/reduction in the density of small lysosomes from 1.235 and 1.20g/ml to 1.225 and 1.185g/ml, respectively.6.6. Proteinuria induced a new population of small lysosomes (density 1.185g/ml) enriched in cathepsin D.

The effect of food restriction (FR) on the kidney cortex lysosomes prepared by rate and isopycnic zonal centrifugation was studied in rats with passive Heymann glomerulonephritis (PHN). FR reduced the renal mass by 41%, but the capacity for handling of labelled endocytosed proteins by the lysosomes was not different from fed PHN rats. While PHN with heavy proteinuria increased the recovery of lysosomal enzymes in the large lysosomes located in the proximal tubule, no changes were observed in FR-PHN rats in spite of significant proteinuria. The density of the small lysosomes was significantly shifted/reduced (from 1,200 and 1,235 g/ml to 1,185 and 1,225 g/ml, respectively) in both fed and FR-PHN rats, suggesting that the handling of extra loads of protein may enhance the absorptive function of small lysosomes found in the lower part of the nephron. FR reduced the mechanical fragility of lysosomes in the kidney cortex of PHN-rats. The highly increased urinary excretion of lysosomal enzymes in fed PHN rats was not observed in FR-PHN rats. As a conclusion, FR reduces both the fragility of lysosomes and the proportion of digestive enzymes in fragile lysosomes. These lysosomal enzymes may be of pathogenic importance in PHN causing cell damage when liberated from disrupted lysosomes.

Human (D54Mg, GaMg) and rat (BT5C, BT4Cn) glioma cells cultured in a chemically defined medium showed reduced growth when compared to serum-supplemented medium. The BT5C cells changed from a flat epithelioid morphology to a more glia-like structure. The serum-free medium caused an aggregation of BT5C cells which spontaneously lost anchorage dependence and continued to grow in suspension as multicellular tumor spheroids. The BT4Cn and human cell lines did not show any change in morphology. Flow cytometric DNA measurements showed no change in ploidy for cells grown in serum-free medium. Cell cycle analysis revealed that the same proportion of cells were proliferating (S and G2M phase cells) in serum-free medium as compared to serum-supplemented medium. The reduced growth is probably due to increased cell cycle time.

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 kJ100 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.