Chrysotile effects on human lung cell carcinoma in culture: 3-D reconstruction and DNA quantification by image analysis

<p>Abstract</p> <p>Background</p> <p>Chrysotile is considered less harmful to human health than other types of asbestos fibers. Its clearance from the lung is faster and, in comparison to amphibole forms of asbestos, chrysotile asbestos fail to accumulate in the lung tissue due to a mechanism involving fibers fragmentation in short pieces. Short exposure to chrysotile has not been associated with any histopathological alteration of lung tissue.</p> <p>Methods</p> <p>The present work focuses on the association of small chrysotile fibers with interphasic and mitotic human lung cancer cells in culture, using for analyses confocal laser scanning microscopy and 3D reconstructions. The main goal was to perform the analysis of abnormalities in mitosis of fibers-containing cells as well as to quantify nuclear DNA content of treated cells during their recovery in fiber-free culture medium.</p> <p>Results</p> <p>HK2 cells treated with chrysotile for 48 h and recovered in additional periods of 24, 48 and 72 h in normal medium showed increased frequency of multinucleated and apoptotic cells. DNA ploidy of the cells submitted to the same chrysotile treatment schedules showed enhanced aneuploidy values. The results were consistent with the high frequency of multipolar spindles observed and with the presence of fibers in the intercellular bridge during cytokinesis.</p> <p>Conclusion</p> <p>The present data show that 48 h chrysotile exposure can cause centrosome amplification, apoptosis and aneuploid cell formation even when long periods of recovery were provided. Internalized fibers seem to interact with the chromatin during mitosis, and they could also interfere in cytokinesis, leading to cytokinesis failure which forms aneuploid or multinucleated cells with centrosome amplification.</p

The Fate of Chrysotile-Induced Multipolar Mitosis and Aneuploid Population in Cultured Lung Cancer Cells

Chrysotile is one of the six types of asbestos, and it is the only one that can still be commercialized in many countries. Exposure to other types of asbestos has been associated with serious diseases, such as lung carcinomas and pleural mesotheliomas. The association of chrysotile exposure with disease is controversial. However, in vitro studies show the mutagenic potential of chrysotile, which can induce DNA and cell damage. The present work aimed to analyze alterations in lung small cell carcinoma cultures after 48 h of chrysotile exposure, followed by 2, 4 and 8 days of recovery in fiber-free culture medium. Some alterations, such as aneuploid cell formation, increased number of cells in G2/M phase and cells in multipolar mitosis were observed even after 8 days of recovery. The presence of chrysotile fibers in the cell cultures was detected and cell morphology was observed by laser scanning confocal microscopy. After 4 and 8 days of recovery, only a few chrysotile fragments were present in some cells, and the cellular morphology was similar to that of control cells. Cells transfected with the GFP-tagged α-tubulin plasmid were treated with chrysotile for 24 or 48 h and cells in multipolar mitosis were observed by time-lapse microscopy. Fates of these cells were established: retention in metaphase, cell death, progression through M phase generating more than two daughter cells or cell fusion during telophase or cytokinesis. Some of them were related to the formation of aneuploid cells and cells with abnormal number of centrosomes

Biological approaches to artificial photosynthesis: general discussion

Metals in Catalysis, Biomimetics & Inorganic Material

Synthetic approaches to artificial photosynthesis: general discussion

Metals in Catalysis, Biomimetics & Inorganic Material

Polypropylene Hollow Fiber Oxygenators: Effect Of The Sorption Of Perfluoropolyethers

The introduction of microporous polypropylene hollow fibers in recent years has brought considerable advances to blood oxygenators. However, lifetime and assembly problems are still unresolved. In this work we tried to rate the oxygen permeation velocity by turning the fibers more hydrophobic through the sorption of a perfluorocarbon. Fomblin HC/25, a perfluoropolyether, is well known for its low surface tension and high affinity for oxygen. Celgard X10, X20, and X30 commercial hollow fibers were tested. The hollow fibers showed high affinity for the perfluoropolyether; swelling was clearly shown. A new system for the measurement of oxygen permeation velocity was developed. The oxygen transport velocity was not significantly changed after sorption. The Celgard microporous hollow fibers impregnated with perfluoropolyether showed no water permeation after 2 months of use, reducing one of the most serious problems in the lifetime of these types of fibers.243168173Voorhees, M.E., Oxygenator technology: The future (1994) Perfusion, 9, pp. 229-232Montoya, J.P., Shanley, C.J., Merz, S.I., Bartlett, R.H., Plasma leakage through microporous membranes: Role of phospholipids (1992) Asaio J, 38, pp. M399-405Cheng, B.T., Leonard, E.F., Light microscopic visualization of plasma intrusion into microporous hollow fiber (1995) ASAIO J, 41, pp. 863-872Lund, L.W., Federspiel, W.J., Hattler, B.G., Gas permeability of hollow fiber membranes in a gas-liquid system (1996) J Membrane Science, 117, pp. 207-219Gaylor, J.D.S., Membrane oxygenators: Influence of design on performance (1994) Perfusion, 9, pp. 173-180Qi, Z., Microporous hollow fibers for gas absorption: II. Mass transfer across the membrane (1985) J Membrane Science, 23, pp. 333-345Costello, M.J., Fane, A.G., Hogan, P.A., Schofield, R.W., The effect of shell side hydrodynamics on the performance of axial flow hollow fiber modules (1993) J Membrane Science, 80, pp. 1-11Wickramasinghe, S.R., Semmens, M.J., Cussler, E.L., Mass transfer in various hollow fiber geometries (1992) J Membrane Science, 69, pp. 235-250Yasuda, H., Lamaze, C.F., Transfer of gas to dissolved oxygen in water via porous and nonporous polymer membrane J Appl Poly Science, 16, pp. 595-601. , 1072Kamo, J., Uchida, M., Hirai, T., Yasida, H., Kanada, K., Takemura, T., A new multilayered composite hollow fiber membrane for artificial lung (1990) Artif Organs, 14 (5), pp. 369-372Yamanouchi, K., Heldebrant, C., Perfluorochemicals as a blood substitute (1992) Chemtech, JUNE, pp. 354-359Rüdiger, S., Methods for forecasting the usefulness of perfluorocarbons for blood substitutes (1989) J Fluorine Chemistry, 42, pp. 403-412Lawson, D.D., Moacanin, J., Scherer, K.V., Terranova T.F., Jr., Inghan, J.D., Methods for the estimation of vapor pressures and oxygen solubilities of fluorochemicals for possible application in artificial blood formulations (1978) J Fluorine Chemistry, 12, pp. 221-236Pantini, G., Moretti, L., Il Fomblin, H.C., Tecnologie chemiche (1988) Ano, 8, pp. 44-48. , 3, Marz

Polypropylene Hollow Fiber Oxygenators: Effect Of The Sorption Of Perfluoropolyethers.

The introduction of microporous polypropylene hollow fibers in recent years has brought considerable advances to blood oxygenators. However, lifetime and assembly problems are still unresolved. In this work we tried to rate the oxygen permeation velocity by turning the fibers more hydrophobic through the sorption of a perfluorocarbon. Fomblin HC/25, a perfluoropolyether, is well known for its low surface tension and high affinity for oxygen. Celgard X10, X20, and X30 commercial hollow fibers were tested. The hollow fibers showed high affinity for the perfluoropolyether; swelling was clearly shown. A new system for the measurement of oxygen permeation velocity was developed. The oxygen transport velocity was not significantly changed after sorption. The Celgard microporous hollow fibers impregnated with perfluoropolyether showed no water permeation after 2 months of use, reducing one of the most serious problems in the lifetime of these types of fibers.24168-7

Characterization of Saccharomyces cerevisiae immobilized onto chrysotile for ethanol production

Saccharomyces cerevisiae (CCT(-)3174 and commercial baker's yeast) was immobilized by adsorption onto chrysotile. The adsorbed yeast cells were easily washed out, but cells grown in situ were strongly attached by entrapment by chrysotile microfibres. In fermentation experiments with 30% (w/v) glucose solution, the immobilized cells showed a 1.3-fold increase in initial reaction velocity. For immobilized CCT 3174, the final ethanol yield was 26% higher than that with free cells. (C) 1998 Society of Chemical Industry.731545

Effect of a calcium-channel blocker (verapamil) on the morphology, cytoskeleton and collagenase activity of human skin fibroblasts

The effects of verapamil modulating collagen biosynthesis have prompted us to study the role of this drug in cultured fibroblasts. In this article, we describe the effects of verapamil on fibroblast behaviour, with special emphasis to phenotypic modifications, reorganisation of actin filaments and secretion of MMP1. Human dermal fibroblasts treated with 50-mu M verapamil changed their normal spindle-shaped morphology to stellate. Treated cells showed discrete reorganisation of actin filaments, as revealed by fluorescein isothiocyanate (FITC)-phalloidin staining and confocal microscopy. We hypothesised that these effects would be associated to lower levels of cytosolic Ca(2+). Indeed, short time loading with calcium green confirmed that verapamil-treated fibroblasts exhibited lower intracellular calcium levels compared to controls. We also observed that verapamil increases the secretion of MMP1 in cultured fibroblasts, as demonstrated by zymography, specific substrate assays and immunoblot. The morphological alterations induced by verapamil are neither cytotoxic nor associated with other dramatic cytoskeleton alterations. Thus we may conclude that this drug enhances collagenase secretion and does not disrupt the major tracks necessary to deliver these enzymes in the extracellular space. The present results suggested that verapamil could be used at physiological levels to enhance collagen I breakdown, and maybe considered a potential candidate for intralesional therapy of wound healing and fibrocontractive diseases. (C) 2010 Elsevier Ltd and ISBI. All rights reserved.FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Characterisation of the size and swelling kinetics of copolymer nano-spheres extracted from an emulsion

Microscopic imaging and technolog

Interaction Between Saccharomyces Cerevisiae And Chrysotile

The interaction between Saccharomyces cerevisiae and chrysotile fibers was studied by scanning electron microscopy. The yeast cells adhere preferentially to the fibrils. In the extreme case, all the adhered fibrils were broken, resulting in a complete coverage of the surface. The chrysotile covered cells showed less buds, but retained metabolic capacities, and were fully active in fermentation experiments after one year. The interaction degree was depending on contact time and adhesion medium. The longer the contact period, the stronger the interaction between the cells and the fibers. Cells adhered in water show poor entrapment after short contact time, but were highly entrapped after longer periods and did not show any agglomerates. Cells adhered in the presence of nutrients showed a lower entrapment and a higher degree of cellular growth.23035Bandypadhyay, K.K., Ghose, T.K., Studies on immobilized Saccharomyces cerevisiae. III Physiology of growth and metabolism on various supports (1982) Biotechnol. Bioeng., 24, pp. 805-815Broaddus, V.C., Asbestos, the mesothelial cell and malignancy: A mater of life or death (1997) Am. J. Respir. Cell Mol. Biol., 17, pp. 657-659Ciesarová, Z., Smogrovicová, D., Dömény, Z., Enhancement of yeast ethanol tolerance by calcium and magnesium (1996) Folia Microbiol., 41, pp. 485-488Cullen, M.R., Chrysotile asbestos: Enough is enough (1998) The Lancet, 351, pp. 1377-1378Fukumori, N., Aoki, N., Sasaki, M., Biological effects of ingested asbestos fibers (VII). Finestructural findings of intravenously injected fibers (1995) Ann. Rep. Tokyo Metr. Res. Lab. P.H., 46, pp. 265-270Fukumori, N., Aoki, N., Sasaki, M., Electron microscopic observations of asbestos fibers in the rat lung after intratracheal instillation (1996) Ann. Rep. Tokyo Metr. Res. Lab. P.H., 47, pp. 303-308Fukumori, N., Aoki, N., Sasaki, M., Ultrastructural changes of macrophages on phagocytosis of asbestos fibers (1997) Ann. Rep. Tokyo Metr. Res. Lab. P.H., 48, pp. 312-317Joekes, I., Moran, P.J.S., Rodrigues, J.A.R., Wendhausen, R., Tonella, E., Cassiola, F., Characterization of Saccharomyces cerevisiae immobilized onto chrysotile for ethanol production (1998) J. Chem Technol. Biotechnol., 73, pp. 54-58Kida, K., Morimura, S., Sonoda, Y., Yanoh, T., The importance of the surface charge on support media for microbial adhesion (1992) J. Ferm. Bioeng., 73, pp. 323-325Kogan, F.M., Nikitina, O.V., Solubility of chrysotile asbestos and basalt fibers in relation to their fibrogenic and carcinogenic action (1994) Environ. Health Perspect., 102, pp. 205-206Langer, A.M., Nolan, R.P., Chrysotile biopersistence in the lungs of persons in the general population and exposed workers (1994) Environ. Health Perspect., 102, pp. 235-239Mozes, N., Marchal, F., Hermesse, M.P., Van Haecht, J.L., Reuliaux, L., Leonard, A.J., Rouxhet, P.G., Immobilization of microorganisms by adhesion: Interplay of electrostatic and nonelectrostatic interactions (1987) Biotechnol. Bioeng., 30, pp. 439-450Nolan, R.P., Langer, A.M., Addison, J., Lung content analysis of cases occupationally exposed to chrysotile asbestos (1994) Environ. Health Perspect., 102, pp. 245-250Norton, S., D'Amore, T., Physiological effects of yeast cell immobilization: Applications for brewing (1994) Enzyme Microb. Technol., 16, pp. 365-375Parizotto, O., Comerlato, M.H., Pedroso, P.R., Moran, P.J.S., Carvalho, M., Joekes, I., (1989) Preparation of chrysotile with high specific surface area. Pat. BR. 8903849Walker, G.M., Maynard, A., Accumulation of magnesium ions during fermentative metabolism in Saccharomyces cerevisiae (1997) J. Industrial Microbiol. Biotechnol., 18, pp. 1-3Wendhausen, R., Moran, P.J.S., Joekes, I., Rodrigues, J.A.R., Continuous process for large-scale preparation of chiral alcohols with baker's yeast immobilized on chrysotile fibers (1998) J. Mol. Cat. B: Enzymatic, 5, pp. 57-6