Human glomerular mesangial IP15 cell line as a suitable model for in vitro cadmium cytotoxicity studies.

Cadmium represents a major environmental pollutant that may induce severe damage, especially in the kidney where cadmium accumulates. While cadmium is known to severely impair renal tubular functions, glomerular structures are also potential targets. Owing to their contractile properties, glomerular mesangial cells play a major role in the control of glomerular hemodynamics and influence the ultrafiltration coefficient. Cell cultures provide alternative and fruitful models for study of in vitro toxicology. However, the use of primary human mesangial cell cultures is hampered by their limited survival span and their rapid dedifferentiation during passages. This study presents a human stable immortalized mesangial cell line, designated IP15. Cell characteristics were investigated by the detection of known mesangial markers, as well as their ability to contract in response to angiotensin II. IP15 cells were used to investigate cadmium uptake and morphological changes such as cell contraction and cytoskeleton protein expression. The IC(50) cytotoxicity index was obtained with 3.55 micromol/L using neutral red assay for 24 h. After cadmium exposure (1 micromol/L, determined as nonlethal concentration), 0.38 microg Cd/mg protein was internalized by the cells as evaluated by inductively coupled plasma optical emission spectrometry (ICP/OES). Cadmium induced a significant cell surface reduction that correlated with smooth-muscle alpha-actin disorganization. Thus, the IP15 cell line is a suitable model for study of in vitro cadmium cytotoxicity in mesangial cells and allows sufficient material to be obtained for future studies of the intracellular effects of cadmium exposure.

Influence of cadmium speciation for the evaluation of in vitro cadmium toxicity on LLC-PK(1) cells.

The main objective of the present work was to assess the potentiality of in vitro models to improve our understanding of cadmium-induced toxicity, especially on epithelial renal cells. Indeed cadmium, a potent toxic metal, poses a serious environmental threat and the mechanisms of its renal toxicity need to be clarified. Cytotoxicity studies presented here were performed in a tubular proximal original established porcine kidney cell line (LLC-PK(1)). We have compared cytotoxicity induced by different chemical cadmium forms in LLC-PK(1) cells as a function of media cell culture pH and protein content. Cadmium stock solutions were prepared either by dissolving cadmium chloride or cadmium sulphate with increasing protein concentrations in the media cell culture. Its pH was monitored during experiments. Cytotoxicity was measured by neutral red uptake after 24 h of exposure. Dose-dependent cytotoxicity curves, calculated with REGTOX, were systematically correlated with pH and protein content. Experiments in vitro revealed that cadmium was dose-dependently toxic for LLC-PK(1) for concentrations ranging from 10(-4) to 10(-6) M. We have noticed a lack of influence of the media cell culture pH on the cadmium cytotoxicity. REGTOX determines closely the EC(50) values but EC(50)CdCl(2)>EC(50)CdSO(4) and cadmium have been assayed with an inductively coupled atomic emission spectrometer (ICP/AES) directly in the media cell culture and the cellular pellet.

Erythroid-specific inhibition of the tal-1 intragenic promoter is due to binding of a repressor to a novel silencer.

The basic helix-loop-helix tal-1 gene plays a key role in hematopoiesis, and its expression is tightly controlled through alternative promoters and complex interactions of cis-acting regulatory elements. tal-1 is not expressed in normal T cells, but its transcription is constitutive in a large proportion of human T cell leukemias. We have previously described a downstream initiation of tal-1 transcription specifically associated with a subset of T cell leukemias that leads to the production of NH(2)-truncated TAL-1 proteins. In this study, we characterize the human promoter (promoter IV), embedded within a GC-rich region in exon IV, responsible for this transcriptional activity. The restriction of promoter IV usage is assured by a novel silencer element in the 3'-untranslated region of the human gene that represses its activity in erythroid but not in T cells. The silencer activity is mediated through binding of a tissue-specific nuclear factor to a novel protein recognition motif (designated tal-RE) in the silencer. Mutation of a single residue within the tal-RE abolishes both specific protein binding and silencing activity. Altogether, our results demonstrate that the tal-1 promoter IV is actively repressed in cells of the erythro-megakaryocytic lineage and that this repression is released in leukemic T cells, resulting in the expression of the tal-1 truncated transcript.

[Nasal washing with Physiomer ... 10 years later: 1988-1998]. / Le lavage de nez avec Physiomer ... 10 ans après: 1988-1998.

The authors present the story of Physiomer. It began in 1988 in Goemar's 'Laboratory of the Sea', with an original idea of making a product manufactured from sea water and transforming it into an isotonic solution, while preserving all the elements of natural sea water, specially the trace elements and the alkaline PH. Scientific analysis has shown that the chemical composition of the product is true to the original, and that it has a positive action on cellular growth in respiratory tract mucosa in experimental culture, and it is very well tolerated. Clinical tests using nasal washings have confirmed beneficial action on the nasal and sinus mucosa in medical disease and after surgery. Tests have been carried out on 410 cases, 344 of which were treated with Physiomer, and on 199 cases after surgery on the nose or sinuses. Physiomer nasal washings have proved their value. It now remains for all the potential qualities of sea water to be demonstrated, using other preparations or other combinations.

In vitro cytocompatibility of radio-opacifiers used in ureteral endoprosthesis.

Ureteral endoprostheses are urinary catheters made of polymeric biomaterials made radio-opaque through the addition of X-ray absorbing additives such as barium, bismuth, tantale or tungsten. The aim of this work was to study the in vitro toxicity of solutions of these radio-opacifiers using two cell culture models. Primary-cultures of human urothelial cells (HUC) arising from normal adult urinary tract and permanent urothelial cell line were used. Solutions at different dilutions were placed into the wells containing monolayers of confluent cells. After 24 h incubation period, the solutions were removed and cell viability and cell metabolic activity tests were performed (Neutral Red assay and MTT assay). At a concentration lower than 1 mg l(-1) the different radio-opacifiers used showed no toxicity. From 1 to 3 mg l(-1) one can note a significant dose-dependent decrease of cell metabolic activity of solely HUC for barium chloride. At 3 mg l(-1) one can note a significant deleterious effect on HUC metabolic activity, with bismuth and tantale. For tungsten, there is no deleterious effect, but on the contrary a significant increase in HUC metabolic activity at a 0.5 mg l(-1) concentration. None of the solutions did provoke alterations in HUC viability for concentrations less than 3 mg l(-1). Interestingly, for permanent cell line one can note a solely significant decrease of cell viability at 3 mg l(-1) for tantale. All the other tested salts on permanent cell line were not significantly different from controls for cell viability as well as cell metabolic activity. HUC culture model may be of relevance for the screening of radio-opacifiers intended for ureteral endoprostheses.

First use of cultured human urothelial cells for biocompatibility assessment: application to urinary catheters.

For several years, studies performed to estimate in vitro biocompatibility of urinary catheters have been carried out using permanent cell lines. But for a rational design of the testing procedure, the cell culture model should relate to the material application. This work presents the results of a probe study designed to obtain an in vitro model of normal human urothelial cells (HUC) and to test the relevance of this system in cytocompatibility experiments of urinary catheters currently used.A comparison is made with continuous cell lines, the use of which is recommended by normalization bodies. We exposed monolayers of HUC (well characterized for their proliferation, qualitative evaluation, and quantitative measurement of cytokeratins) and two continuous human cell lines to liquid extracts (either pure or diluted in the culture medium) of nine available catheters, including positive (latex) and negative controls, for a 24 h incubation. Then colorimetric assays (Neutral Red and MTT) were performed. The extracts of two polyurethanes provoked a significant toxic effect on HUC only, suggesting differences in sensitivity between the models used. This effect could be due to the presence of a great amount of barium (used as a radioopacifier) in extracts, as highlighted by results of absorption emission spectroscopy. A culture model of HUC may be of relevance for the screening of materials intended for urological practice.

Saturnism caused by hand-made plates: partial diagnosis by a computer-aided program.

A man, aged 41 years, suffering from anaemia and abdominal pains was admitted to the Department of Medicine. Over the previous 2 years he had had several periods in hospital for these symptoms. There was, apparently, no occupational or accidental exposure to toxic substances and a correct diagnosis of the condition had not been possible. The computer-aided program AIDEDIAG II was therefore used to attempt a diagnosis. This approach indicated possible saturnism which was confirmed by metabolic and lead analyses. The lead source was identified as the hand-made food-plates used by the patient for his meals.

[Effect of water containing calcium and magnesium sulfates on the elimination of cholesterol in the rat]. / Rôle d'une eau sulfatée calcique et magnésienne sur l'élimination du cholestérol chez le rat.

In the rat, the activity of the thermal water of Capvern and of its ionic components on the modification of the flow rate and composition of hepatic bile has been investigated. Two groups of rats were selected: the first group received per os an overload of the thermal water during six weeks. At that time on empty stomach a great increase of biliary phospholipids was observed. An intraduodenal injection of the thermal water produced a significant and rapid increase of biliary flow rate and biliary cholesterol. the animals of the second group received through intraduodenal injections the thermal water or an anionic solution composed of calcium, of magnesium sulphate or of both salts at their concentration in the thermal water, respectively. We observed an increase in biliary flow rate and biliary calcium concentration in the rats receiving the solution of calcium sulphate only and an increase of choleresis in the rats receiving the thermal water only. These data suggest that the thermal water has a specific action on the metabolism of cholesterol in increasing its biliary elimination particularly through the calcium ion content of the water.