(1/1076) Cyclosporin exerts a direct fibrogenic effect on human tubulointerstitial cells: roles of insulin-like growth factor I, transforming growth factor beta1, and platelet-derived growth factor.
To assess the direct fibrogenic effects of cyclosporin A (CyA) on the human tubulointerstitium, primary cultures of human renal proximal tubule cells (PTC) and renal cortical fibroblasts (CF) were incubated for 24 h with various concentrations of CyA. Cytotoxicity was confirmed in both cell populations by dose-dependent inhibition of thymidine incorporation, viability, and PTC apical sodium-hydrogen exchange activity (ethylisopropylamiloride-sensitive apical 22Na+ uptake). Compared with controls, both 500 and 1000 ng/ml CyA significantly stimulated CF collagen synthesis (proline incorporation 4.6 +/- 0.4, 6.5 +/- 0.8, and 7.1 +/- 1.0%, respectively; p <.05) and inhibited matrix metalloproteinase-2 (100%, 85.7 +/- 10.0%, and 38.8 +/- 9.2%) and matrix metalloproteinase-9 activity (100%, 110.6 +/- 19.0%, and 49.9 +/- 12.8%). CyA did not affect CF secretion of transforming growth factor beta1, but markedly stimulated insulin-like growth factor-I (IGF-I) secretion and inhibited secretion of both IGF-I binding protein-(IGFBP)-3 and IGFBP-2. CyA-induced CF collagen synthesis was abrogated by 5 microgram/ml anti-IGF-I receptor antibody, but not by 5 microgram/ml murine nonimmune globulin. Increasing concentrations of CyA progressively augmented PTC secretion of the fibrogenic cytokines transforming growth factor-beta1 and platelet-derived growth factor. These results indicate that clinically relevant concentrations of CyA are directly toxic to PTC and CF, irrespective of hemodynamic effects, and promote interstitial fibrosis by inhibiting matrix degradation and stimulating cortical fibroblast collagen synthesis via induction of autocrine IGF-I action. The latter effect may be further accentuated by the ability of CyA to augment secretion of transforming growth factor beta1 and platelet-derived growth factor by PTCs. (+info)
(2/1076) Increased E1AF expression in mouse fibrosarcoma promotes metastasis through induction of MT1-MMP expression.
In this study, we investigated the role of E1AF, a member of ets family transcription factor, in the acquisition of metastatic capacity by non-metastatic mouse fibrosarcoma cell clone, QR-32. The QR-32 cell clone grows progressively after co-implantation with gelatin sponge in syngeneic C57BL/6 mice. The cell lines (QRsP) established from arising tumors after the co-implantation exhibited enhanced tumorigenicity and pulmonary metastasis in vivo as compared with parent QR-32 cells. The enhanced pulmonary metastasis of QRsP cells was correlated well with augmented production of matrix metalloproteinase-2 (MMP-2) and increased expression of membrane-type 1-MMP (MT1-MMP). The QRsP cells also acquired higher chemokinetic activities to fibronectin and higher invasive activities through a reconstituted basement membrane. Furthermore we observed the elevated mRNA expression of E1AF in QRsP cells compared to parent QR-32 cells. Therefore, we transfected QR-32 cells with E1AF cDNA. Overexpression of E1AF in the QR-32 cells resulted in the induction of MT1-MMP expression and converting an exogenously added precursor MMP-2 into active form. E1AF transfectants exhibited more motile and invasive activities, and moderately increased pulmonary metastatic activities than parental QR-32 cells in vivo, although their metastatic activities were lower than those of QRsP cells. These findings suggest that the increased expression of E1AF in fibrosarcoma contributes to invasive phenotypes including MT1-MMP expression and enhanced cell migration, but not sufficient for exhibiting highly metastatic activity in vivo. (+info)
(3/1076) Growth of human tumor cells in macroporous microcarriers results in p53-independent, decreased cisplatin sensitivity relative to monolayers.
Multicellular contact has been shown to influence the in vitro sensitivity of cells to drug treatment. We investigated the use of macroporous gelatin microcarriers, CultiSpher-G, as a convenient laboratory system for the molecular analysis of this "contact effect". We determined that human A549 cells can be grown in CultiSphers with growth and cell cycle parameters similar to those of monolayers. In addition, cells in CultiSphers express less p27/kip1, an indicator of cell cycle arrest, than equivalent cells in monolayers. When treated with drugs, A549 cells grown in CultiSphers or monolayers accumulate equivalent amounts of platinum-DNA adducts and similar amounts of doxorubicin. Moreover, A549 and KB-3-1 cells in CultiSphers have significantly decreased sensitivity to cis-platinum(II)diammine dichloride (cisplatin), 4-hydroperoxycyclophosphamide, doxorubicin, and paclitaxel (taxol) compared with cells in monolayers when assayed by clonogenic survival. Cisplatin treatment in monolayers or CultiSphers did not result in apoptotic cell death. In contrast, paclitaxel caused a significant amount of sub-G1 DNA, an indicator of apoptosis, which was diminished when cells were grown in CultiSphers compared with monolayers. When grown in CultiSphers, cells with abrogated p53 function (A549/16E6 and NCI-H1299) were less sensitive to cisplatin than the corresponding monolayer cells, indicating that the decrease in sensitivity is p53 independent. Taken together, the data suggest that CultiSpher-G microcarriers are a useful in vitro system to examine the effects of three-dimensional cell contact on drug sensitivity of human tumor cells. (+info)
(4/1076) Dietary chromic oxide does not affect the utilization of organic compounds but can alter the utilization of mineral salts in gilthead sea bream Sparus aurata.
This study was conducted to determine whether the level of chromic oxide supplemented to diets containing gelatinized starch as the carbohydrate source affects digestibility, body composition, growth performances, and liver enzyme activities in gilthead sea bream, Sparus aurata. Gilthead sea bream fingerlings were fed diets containing gelatinized corn starch as the carbohydrate source and several levels of chromic oxide (0, 5, 10 and 20 g/kg) for 6 wk. No effect of dietary chromium level was detected on carbon, nitrogen, or dry matter digestibility. Calcium and phosphorus digestibility were higher in fish fed the diet supplemented with 5 g/kg chromic oxide than in fish fed the other supplemented diets. Dietary chromium did not affect dry matter, carbon, nitrogen, protein, or lipid concentrations in fish. However, fish fed 5 g/kg chromic oxide generally had higher levels of calcium, phosphorus, and ash than fish fed the other Cr-containing diets. Chromium concentration was significantly higher in fish fed the diets with 0.5 and 1% chromic oxide than in fish fed the control diet. Chromium supplementation of the diets did not affect the specific growth rate, the food efficiency ratio, the protein efficiency ratio, or, protein or nitrogen retention of the fish. Blood glucose and the activity of several liver enzymes involved in carbohydrate metabolism were unaffected by dietary chromic oxide. Alanine aminotransferase was lower in the fish fed the diet with 10 g/kg of chromic oxide than in unsupplemented controls. Our results indicate that chromic oxide can be used as a neutral marker in fish nutrition studies involving organic compounds, but not mineral salts. (+info)
(5/1076) Reactivity of the immunoglobulin E in bovine gelatin-sensitive children to gelatins from various animals.
It has been reported that most children who showed anaphylaxis to measles, mumps and rubella vaccines containing bovine gelatin as a stabilizer have anti-bovine gelatin IgE. The present study was designed to investigate the reactivity of IgE in bovine gelatin-sensitive children to gelatins from various animals, and the antigenic cross-reactivity between the gelatins. Serum samples taken from 10 children who showed anaphylaxis to vaccines containing bovine gelatin were used in this study. The level of anti-bovine gelatin IgE in these serum samples ranged from 11.0 to 251 Ua/ml. The IgE in most of the children reacted to kangaroo and mouse gelatins, to which they had had little or no exposure as a food or a vaccine stabilizer. The IgE binding to kangaroo and mouse gelatins was completely inhibited by bovine gelatin, whereas reciprocal inhibition was not complete, indicating that antigenic cross-reactivity is present between the mammalian gelatins. Only one child had strong IgE reactivity to fish gelatins, and this reactivity was not inhibited by bovine gelatin, indicating that no antigenic cross-reactivity exists between bovine and fish gelatins. Most of the children who displayed sensitivity to bovine gelatin showed IgE reactivity to other mammalian gelatins. This reactivity may be due primarily to the antigenic cross-reactivity between mammalian gelatins. (+info)
(6/1076) Sensory perception is related to the rate of change of volatile concentration in-nose during eating of model gels.
The relationship between perceived aroma and the volatile concentration measured in-nose was investigated during eating of a model food. Sensory ranking and time-intensity analysis (TI) were used to measure perceived aroma, while in-nose volatile concentration was monitored by atmospheric pressure ionization mass spectrometry, which produced time release data. A gelatine-sucrose gel with a range of gelatine concentrations (2-8% w/w) and flavoured with furfuryl acetate was used as the model food. Sensory scaling showed decreased flavour intensities and TI showed a decrease in the flavour perceived over time, as the gelatine concentration increased. Studies in model systems and in people demonstrated that the different rates of release observed for different gelatine concentrations were not due to binding of volatile to protein in the gel, nor to mucous membranes, but were due to different rates of gel breakdown in-mouth. There were no significant differences in the maximum in-nose volatile concentrations for the different gelatine concentrations, so the amount of volatile present did not correlate well with the sensory analysis. However, the rates of volatile release were different for the different gels and showed a good correlation with sensory data. (+info)
(7/1076) Pseudo-proteinuria following gelofusine infusion.
Transient massive proteinuria following cardiopulmonary bypass surgery was observed. It was characterized and attributed to post-operative gelofusine infusion. Gelofusine was found to interfere with dye binding but not immunochemical assays of proteinuria. Proteinuria following gelofusine infusion may not reflect underlying glomerular pathology. (+info)
(8/1076) Production and inhibition of the gelatinolytic matrix metalloproteinases in a human model of vein graft stenosis.
OBJECTIVES: human vein graft stenoses are caused by intimal hyperplasia, a process which is characterised by extensive degradation and accumulation of extracellular matrix. This study investigated the role of the matrix metalloproteinases (MMPs) - the principal physiological mediators of extracellular matrix degradation - in the development of intimal hyperplasia in cultured human long saphenous vein. DESIGN: experimental study. MATERIALS AND METHODS: paired venous segments with the endothelium intact or denuded were cultured in standard conditions for 14 days. At the termination of culture, MMPs were extracted from one half of the tissue, whilst the remainder of the vein was prepared for histological examination. RESULTS: stereologic analysis revealed that the endothelium intact veins developed a significantly thicker neointima when compared to the denuded venous segments (20 micron v. 0 micron, p=0.006). Quantification of MMPs by substrate gel enzymography demonstrated that the development of a neointima was associated with increased production of the gelatinolytic MMP-9 (p=0. 03) in intact veins. Immunocytochemistry showed that the MMP-9 localised to the internal elastic lumina, which suggested a role in facilitating smooth-muscle-cell migration into the intima. The role of MMPs-2 and -9 in intimal hyperplasia was further investigated by culturing intact venous segments with a therapeutic concentration of doxycycline--a potent MMP inhibitor. These experiments demonstrated that a therapeutic dose of doxycycline significantly reduced neointimal thickness (control 21 micron, doxycycline 10 mg/l-5.5 micron), in conjunction with a significant reduction in the production of MMP-9. CONCLUSIONS: these data suggest that elevated levels of MMPs may play a significant role in the development of human intimal hyperplasia and that inhibition of these enzymes may offer a potential therapeutic strategy for the prevention of hyperplastic lesions. (+info)