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Cellular Matrix (cellular + matrix)
Kinds of Cellular Matrix Selected AbstractsTissue Engineering Based on Cell Sheet Technology,ADVANCED MATERIALS, Issue 20 2007N. Matsuda Abstract Cell sheet technology enables novel approaches to tissue engineering without the use of biodegradable scaffolds. Cell sheet technology consists of a temperature-responsive culture dish, which enables reversible cell adhesion to and detachment from the dish surface by controllable hydrophobicity of the surface. This allows for a non-invasive harvest of cultured cells as an intact monolayer cell sheet including deposited extra cellular matrices. The monolayer cell sheet can be transplanted to host tissues without using biodegradable scaffolds and sutures. Thick tissue constructs and patterned cell sheets using two or more kinds of cell source are also developed by means of layered cell sheets in vitro. This Progress Report summarizes temperature-controlled cell adhesion-detachment behavior and applications of the cell sheet technology to regeneration of cornea, periodontal ligament, bladder epithelia, oesophageal epithelia, myocardium, and liver. [source] SiOC Ceramic Monoliths with Hierarchical PorosityINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2010Cekdar Vakifahmetoglu SiOC glass monoliths possessing hierarchical porosity were produced by a one-pot processing method. Periodic mesoporous organosilica (PMO) particles were embedded into a foamed siloxane preceramic polymer. After pyrolysis at 1000°C in inert atmosphere, open celled, permeable SiOC ceramic monoliths with a high amount of pores, ranging in size from hundred of micrometers to a few nanometers, were obtained. The components possessed a specific surface area of 137 m2/g, indicating the retention of most of the mesopores after the pyrolytic conversion of the PMO precursor particles. These fillers converted to truncated rhombic dodecahedral SiOC mesoporous micron-sized grains, homogeneously distributed throughout the SiOC cellular matrix. The produced porous ceramics possessed compression strength of about 1.7 MPa, which is adequate for their use in several engineering applications. [source] Growth of osteoblast-like cells on biomimetic apatite-coated chitosan scaffoldsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008I. Manjubala Abstract Porous scaffold materials that can provide a framework for the cells to adhere, proliferate, and create extracellular matrix are considered to be suitable materials for bone regeneration. Interconnected porous chitosan scaffolds were prepared by freeze-drying method, and were mineralized by calcium and phosphate solution by double-diffusion method to form nanoapatite in chitosan matrix. The mineralized chitosan scaffold contains hydroxyapatite nanocrystals on the surface and also within the pore channels of the scaffold. To assess the effect of apatite and porosity of the scaffolds on cells, human osteoblast (SaOS-2) cells were cultured on unmineralized and mineralized chitosan scaffolds. The cell growth on the mineralized scaffolds and on the pure chitosan scaffold shows a similar growth trend. The total protein content and alkaline phosphatase enzyme activity of the cells grown on scaffolds were quantified, and were found to increase over time in mineralized scaffold after 1 and 3 weeks of culture. The electron microscopy of the cell-seeded scaffolds showed that most of the outer macropores became sealed off by a continuous layer of cells. The cells spanned around the pore wall and formed extra cellular matrix, consisting mainly of collagen in mineralized scaffolds. The hydroxyproline content also confirmed the formation of the collagen matrix by cells in mineralized scaffolds. This study demonstrated that the presence of apatite nanocrystals in chitosan scaffolds does not significantly influence the growth of cells, but does induce the formation of extracellular matrix and therefore has the potential to serve for bone tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Extraction, Identification, and Quantification of Flavonoids and Phenolic Acids in Electron Beam-Irradiated Almond Skin PowderJOURNAL OF FOOD SCIENCE, Issue 3 2009A.S. Teets ABSTRACT:, The effect of electron beam irradiation doses from 0 to 30 kGy on extraction yield and phenolic compounds was evaluated in almond skin phenolic extracts (ASPE). Total soluble phenols and distribution of phenolic compounds from acidified methanol ASPE and 52% methanol ASPE were quantified using Folin,Ciocalteau method, liquid chromatography with diode array and fluorescence detection, and negative ion electrospray-mass spectrometry. Electron beam irradiation increased extraction yield by as much as 23%, with the greatest increase observed in the acidified methanol ASPE. Irradiated samples extracted with acidified methanol also exhibited an increase in extractable phenols (Folin,Ciocalteau) and total HPLC-resolved phenolics at all irradiation doses. Samples extracted with 52% methanol exhibited an increase at 10 and 20 kGy, but a 31% decrease at 30 kGy. An increase in aglycones respective to their glycosides was not observed with irradiation. Therefore, the increase in phenolics was attributed to release of phenolics from their cellular matrix. [source] Extrapolating in vitro metabolic interactions to isolated perfused liver: Predictions of metabolic interactions between R -bufuralol, bunitrolol, and debrisoquineJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2010Sami Haddad Abstract Drug,drug interactions (DDIs) are a great concern to the selection of new drug candidates. While in vitro screening assays for DDI are a routine procedure in preclinical research, their interpretation and relevance for the in vivo situation still represent a major challenge. The objective of the present study was to develop a novel mechanistic modeling approach to quantitatively predict DDI solely based upon in vitro data. The overall strategy consisted of developing a model of the liver with physiological details on three subcompartments: the sinusoidal space, the space of Disse, and the cellular matrix. The substrate and inhibitor concentrations available to the metabolizing enzyme were modeled with respect to time and were used to relate the in vitro inhibition constant (Ki) to the in vivo situation. The development of the liver model was supported by experimental studies in a stepwise fashion: (i) characterizing the interactions between the three selected drugs (R -bufuralol (BUF), bunitrolol (BUN), and debrisoquine (DBQ)) in microsomal incubations, (ii) modeling DDI based on binary mixtures model for all the possible pairs of interactions (BUF,BUN, BUF,DBQ, BUN,DBQ) describing a mutual competitive inhibition between the compounds, (iii) incorporating in the binary mixtures model the related constants determined in vitro for the inhibition, metabolism, transport, and partition coefficients of each compound, and (iv) validating the overall liver model for the prediction of the perfusate kinetics of each drug determined in isolated perfused rat liver (IPRL) for the single and paired compounds. Results from microsomal coincubations showed that competitive inhibition was the mechanism of interactions between all three compounds, as expected since those compounds are all substrates of rat CYP2D2. For each drug, the Ki values estimated were similar to their Km values for CYP2D2 indicative of a competition for the same substrate-binding site. Comparison of the performance between the novel liver physiologically based pharmacokinetic (PBPK) model and published empirical models in simulating the perfusate concentration,time profile was based on the area under the curve (AUC) and the shape of the curve of the perfusate time course. The present liver PBPK model was able to quantitatively predict the metabolic interactions determined during the perfusions of mixtures of BUF,DBQ and BUN,DBQ. However, a lower degree of accuracy was obtained for the mixtures of BUF,BUN, potentially due to some interindividual variability in the relative proportion of CYP2D1 and CYP2D2 isoenzymes, both involved in BUF metabolism. Overall, in this metabolic interaction prediction exercise, the PBPK model clearly showed to be the best predictor of perfusate kinetics compared to more empirical models. The present study demonstrated the potential of the mechanistic liver model to enable predictions of metabolic DDI under in vivo condition solely from in vitro information. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4406,4426, 2010 [source] Varying ratios of wavelengths in dual wavelength LED photomodulation alters gene expression profiles in human skin fibroblastsLASERS IN SURGERY AND MEDICINE, Issue 6 2010D.H. McDaniel MD Abstract Background and Objective LED photomodulation has been shown to profoundly influence cellular behavior. A variety of parameters with LED photomodulation can alter cellular response in vitro. The effects of one visible and one infrared wavelength were evaluated to determine the optimal ratio to produce a net increase in dermal collagen by altering the ratio of total energy output of each wavelength. The ratio between the two wavelengths (590 and 870,nm) was shifted in 25% increments. Study Design/Materials and Methods Human skin fibroblasts in culture were exposed to a 590/870,nm LED array with total combined energy density fixed at 4.0,mW/cm.. The ratio of 590/870,nm tested parameters were: 100/0%, 75/25%, 50/50%, 25/75%, and 0/100%. These ratios were delivered using pulsed duty cycle of exposure (250,milliseconds "on" time/100,milliseconds "off" time/100,pulses) for a total energy fluence of 0.1,J/cm.. Gene expression was examined using commercially available extra cellular matrix and adhesion molecule RT PCR Arrays (SA Biosciences, Fredrick, MD) at 24,hours post-exposure. Results Different expression profiles were noticed for each of the ratios studied. Overall, there was an average (in an 80 gene array) of 6% expression difference in up or downregulation between the arrays. The greatest increase in collagen I and decrease in collagenase (MMP-1) was observed with 75/25% ratio of 590/870,nm. The addition of increasing proportions of IR wavelengths causes alteration in gene expression profile. The ratios of the wavelengths caused variation in magnitude of expression. Conclusions Cell metabolism and gene expression can be altered by simultaneous exposure to multiple wavelengths of low energy light. Varying the ratios of specific wavelength intensity in both visible and near infrared light therapy can strongly influence resulting fibroblast gene expression patterns. Lasers Surg. Med. 42:540,545, 2010. © 2010 Wiley,Liss, Inc. [source] Cellular Adhesion, Proliferation and Viability on Conducting Polymer SubstratesMACROMOLECULAR BIOSCIENCE, Issue 12 2008Luis J. del Valle Abstract This work reports a comprehensive study about cell adhesion and proliferation on the surface of different electroactive substrates formed by ,-conjugated polymers. Biological assays were performed considering four different cellular lines: two epithelial and two fibroblasts. On the other hand, the electroactivity of the three conducting systems was determined in physiological conditions. Results indicate that the three substrates behave as a cellular matrix, even though compatibility with cells is larger for PPy and the 3-layered system. Furthermore, the three polymeric systems are electro-compatible with the cellular monolayers. [source] Serum levels of matrix metalloproteinase-9, tissue inhibitors of metalloproteinase-1 and their ratio are associated with impaired lung function in the elderly: A population-based studyRESPIROLOGY, Issue 3 2010Inga S. ÓLAFSDÓTTIR ABSTRACT Background and objective: Matrix metalloproteinases (MMP) and their inhibitors, tissue inhibitors of metalloproteinases (TIMP), regulate homeostasis and turnover of the extra cellular matrix. The aim of this study was to investigate the associations of serum MMP-9 and TIMP-1 with lung function. Methods: Spirometry was performed in a population-based sample of 888 subjects aged 70 years. Serum MMP-9 and TIMP-1 concentrations were measured by ELISA. Results: Lower FEV1 values were associated with higher serum levels of MMP-9 (P = 0.001) and TIMP-1 (P < 0.001), and a higher ratio of MMP-9 to TIMP-1 (P = 0.02). These associations were significant after adjustment for gender, weight, height, BMI, current smoking, pack years of smoking and the time for which samples were frozen. After stratification for gender, the associations between FEV1 and MMP-9, TIMP-1, and their ratio, were significant in men but not in women. Conclusions: Lower FEV1 was significantly but weakly associated with higher serum levels of MMP-9, TIMP-1 and a higher MMP-9/TIMP-1 ratio. This association was stronger in men than in women, suggesting a possible role for extracellular matrix remodelling in the development of impaired lung function. These associations may also partly explain the association between low FEV1 and cardiovascular disease. [source] | ||||||||||||||||