Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The exposure of employees to airborne dust and microorganisms was assessed in a waste processing plant established to recover reusable materials from unsorted domestic and industrial waste. Exposure criteria considered relevant were the quantity of the individual size-selected particle fractions, the morphological properties of the particles, their heavy metal content, and the degree of their contamination with various microorganisms and mold. In addition, separate microbiological analyses to determine potential pathogen concentrations in the air were made. The highest concentrations of total and fine dust were measured in the waste delivery area. A close correlation between the frequency of deliveries and the level of dust exposure was observed. In this area, fine dust concentrations exceeded the threshold limit value of 6 mg/m3 repeatedly for shorter periods. The average fine dust concentration during an entire work-shift, however, was considerably lower than this value. Particles with an aerodynamic diameter of 2 to 7 microns predominated both in the waste delivery and the processing areas. Fibrous dust particles were present in smaller numbers than spherical particles and consisted mainly of organic materials. Natural and artificial inorganic fibers were found only occasionally. The concentrations of lead, cadmium, nickel and mercury were considerably lower than the corresponding MAK and TRK values, and were--with the exception of lead--in the range of the respective metal concentrations in the atmosphere of urban areas. Microscopical examinations of used protective masks (protection category P2) revealed that dust particles were deposited even on the inner side of the masks. Most of the particles on this side were very small and carried nickel or titanium. Microorganism concentrations measured in air from the highly dust-exposed areas of the plant showed values up to 6.9 x 10(5) cfu/m3, with a mold content of 6.6 x 10(4) cfu/m3. Approximately 90% of the microorganisms were deposited on particles of the fine dust fraction (particle size < 7 microns), and more than 50% contaminated particles with an aerodynamic diameter of 2 to 4.7 microns. In the compost facility, mold concentrations of up to 8.4 x 10(5) cfu/m3 were measured. In contrast, the level of microbial contamination in the filtered air from the compost facility did not exceed the concentration measured in air outside the plant. The data which were obtained during the winter months are probably at the lower end of the average exposure range over the entire year. In regard to exposure assessment, it should be mentioned that particles with a size of 4 to 7 microns are not really "inert" particles, since they are preferential carriers for heavy metals and microorganisms. More studies in the future should be performed to establish, whether the level of exposure to microorganisms can be estimated indirectly by the determination of dust exposure.
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PMID:[Dust and microorganism count at delivery, sorting and composting of home refuse and home refuse-like industrial waste]. 940 5

When osteoblasts are cultured on surfaces of increasing microroughness, they exhibit decreases in proliferation, increases in differentiation and local factor production, and enhanced response to 1alpha,25(OH)(2)D(3). The cells interact with surfaces through integrins, which signal by the same pathways used by 1alpha,25(OH)(2)D(3), including protein kinase C via phospholipase C and protein kinase A via phospholipase A(2). This provides opportunities for crosstalk that may contribute to the synergistic effects of surface roughness and the vitamin D metabolite. Because these pathways converge at mitogen-activated protein kinase (MAPK), we tested the hypothesis that the extracellular signal-regulated kinase (ERK1/2) subclass of MAPKs mediates the effects of surface roughness and 1alpha,25(OH)(2)D(3). MG63 osteoblast-like osteosarcoma cells were cultured on commercially pure Ti disks with various surface roughnesses: pretreatment (PT; 0.6 microm average roughness [Ra]), coarse grit-blasted and acid-etched (SLA; 4 microm RA), and titanium plasma-sprayed (TPS; 5.2-microm R(a)). At confluence, cells were treated for 24 h with control media or media containing 10(-7) M 1alpha,25(OH)(2)D(3). One-half of the cultures received 1 microm or 10 microm PD98059, a specific inhibitor of the ERK family of MAPKs. PD98059 alone did not affect proliferation, osteocalcin production, or production of transforming growth factor-beta1 or nitric oxide, regardless of the surface roughness. Alkaline phosphatase was reduced by the inhibition of the ERK family kinases on all surfaces to a comparable extent. However, when PD98059 was added to the cultures with 1alpha,25(OH)(2)D(3), the effects of the seco-steroid were blocked, including the synergistic increases seen in MG63 cells cultured on SLA or TPS. These results indicate that ERK1/2 MAPK is required for the maintenance of alkaline phosphatase at control levels and that the effects of 1alpha,25(OH)(2)D(3) are mediated by ERK1/2. However, the effects of surface roughness are not due to the ERK family of MAPKs. This suggests that alternative pathways may be used, including those mediated by other MAPK subclasses.
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PMID:Osteoblast response to titanium surface roughness and 1alpha,25-(OH)(2)D(3) is mediated through the mitogen-activated protein kinase (MAPK) pathway. 1137 60

To improve implant biocompatibility, we developed a simple cost-effective thermal surface treatment allowing an increase in the oxide layer thickness of a titanium (Ti) alloy used in orthopaedic implants. The goal of this study was to test in vitro the reaction of osteoblasts to the developed surface treatment and to compare it to the osteoblast reaction to two other surface treatments currently used in the practice of implant surgery. Quantification of osteoblast gene expression on a large scale was used in this study. The kinetics of gene expression over 120 h was followed for 58 genes to quantify the effect of the developed surface treatment. Twenty eight genes were further selected to compare the effects of surface treatments on osteoblasts. Based on the genes studied, we could propose a general pathway for the cell reaction according to the surface treatments used: (1) metal ion release changes the time course of gene expression in the FAK pathway; (2) once the accumulation of metal ions released from the Ti surface exceeds a threshold value, cell growth is diminished and apoptosis may be activated; (3) PTK up-regulation is also induced by metal ion release; (4) the expression of Bcl-2 family and Bax may suggest that metal ions induce apoptosis. The developed treatment seems to increase the Ti-6Al-4V biocompatibility as highlighted by the lower impact of this treatment by the different pathways studied, on the lower inflammatory reaction that could be induced, as well as by the lower induced osteoblast apoptosis compared to the two other surface treatments.
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PMID:Large-scale gene expression analysis of osteoblasts cultured on three different Ti-6Al-4V surface treatments. 1219 22

Hydroxyapatite (HA) and other calcium phosphates were synthesized on titanium plates by a solid-gas state reaction of sputtered CaO and vaporized P(2)O(5). The calcium phosphates formed were HA, beta-tricalcium phosphate (beta-TCP; Ca(3)(PO(4))(2)), beta-calcium pyrophosphate (beta-PYR; Ca(2)P(2)O(7)), and beta-calcium metaphosphate (beta-MET; Ca(2)(PO(3))(2)). Their formation depended on the ratio of the sputtered CaO and the reacting P(2)O(5). For a mole ratio of CaO/P(2)O(5)=4 (Ca/P=2), an HA film was synthesized. The surface roughness increased by over seven times after the solid-gas state reaction from Ra = 0.16+/-0.02 microm (for the CaO film) to Ra = 1.15+/-0.25 microm (for the reacted film). The synthesized HA film-coated titanium plates and control non-coated titanium plates were implanted in the femora of two dogs for a period of two, four and 12 weeks, and observed using a soft X-ray radiograph and histological sections. New bone formation was observed without any connective tissue at four weeks around the HA film, whereas over the 12 week experimental period, there was no new bone formation around the control and connective tissue was observed over all periods, reaching a thickness of more than 200 microm at 12 weeks.
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PMID:Preparation and osteocompatibility of hydroxyapatite coated on titanium from the reaction of sputtered CaO and vaporized P2O5. 1265 25

Up to now, most of the studies addressing the critical roles played by protrusive and contractile cell-matrix contacts in cell adhesion, guidance, migration, matrix assembly, and activation of signaling molecules have been performed on two-dimensional surfaces. Here, we analysed the organization of chondrosarcoma cell contacts in a new three-dimensional environment made of titanium beads. Surface charges were modified by deposition of polyelectrolyte multilayer films built up by alternated polycations poly-(L-lysine) or poly(allylamine hydrochloride) and polyanions poly-(L-glutamic acid) or poly(sodium 4-styrenesulfonate). Negatively charged 3-D titanium surfaces amplified the occurrence and length of cell protrusions. These protrusions had pseudopod characteristics extended to 200 microm in length, growing off the substratum to distant beads. Pseudopod formation is inhibited by the exocytosis inhibitor concanamycin A and is triggered by a secreted factor. Chondrosarcoma cells adhering on uncoated or on negatively charged surfaces contained discrete focal spots of vinculin and actin cables. In cells plated onto these surfaces, phosphorylation of p44/42 MAPK/ERK was twofold increased. In contrast, no cytoskeletal vinculin and actin organization was observed when the surface was positively charged. These data suggest that chondrosarcoma cells adapt a more stable adhesion on uncoated or negatively charged surfaces. This point may be critical in tissue engineering strategies designed for cartilage repair.
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PMID:3-D surface charges modulate protrusive and contractile contacts of chondrosarcoma cells. 1456 95

Chemokines, or chemotactic cytokines, are major regulators of the inflammatory response and have been identified as pathogenic factors in the periprosthetic soft tissue. Particulate wear debris induced NF-kappaB activation, the major transcriptional regulator of IL-8 and MCP-1 pro-inflammatory genes and, indeed, both IL-8 and MCP-1 chemokine gene expressions were upregulated in titanium particulate-stimulated human osteoblasts. Here, we demonstrate that phagocytosed particles activate the IL-8 gene promoter via a NF-kappaB-mediated mechanism. Transfection of a dominant negative mutant IkappaBalpha protein that cannot be serine phosphorylated led to suppression of IL-8 promoter activity. The p65/RelA NF-kappaB subunit activity was affected in both a time- and titanium particle concentration-dependent fashion. Titanium particles led to increased ERK, JNK, and p38 activation in MG-63 osteoblast cells, and IL-8 protein release was suppressed by specific inhibitors of the ERK and p38 MAPK pathways. Together, our results suggest that wear debris particles induce chemokine expression in osteoblasts via NF-kappaB-mediated transcriptional activation, which is controlled by the MAPK signal transduction pathway.
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PMID:Chemokine IL-8 induction by particulate wear debris in osteoblasts is mediated by NF-kappaB. 1595 Apr 27

The aim of this study was to evaluate the potential role of polyglycolic acid (PGA), poly(glycolic acid-epsilon-caprolactone) (PGCL), poly(L-lactic acid-glycolic acid) (PLGA), poly(L-lactic acid-epsilon-caprolactone, 75:25 (w/w)) [P(LA-CL)25], poly-epsilon-caprolactone (tetrabutoxy titanium) [PCL(Ti)], and fullerene C-60 dimalonic acid (DMA) in cartilage transplants. After 4 weeks of culture of human articular cartilage, the levels of cell proliferation and differentiation and the expression of cartilage-specific matrix genes were estimated. The relationship between cell differentiation and gap junction protein connexin 43 (Cx43) was also evaluated. All materials except PCL(Ti) retained cell proliferation activities similar to the controls. Cell differentiation levels from the highest to the lowest were in the following order: PGA >> PLGA > PGCL > Control = DMSO > P(LA-CL)25 = PCL(Ti) >> fullerene C-60 DMA. Expression of the collagen type II gene was selectively upregulated for PGA, PGCL, and PLGA and slightly increased for P(LA-CL)25 polymers but was downregulated for fullerene C-60 DMA. Aggrecan gene expression was strongest with PGA and was consistently expressed with other matrices, especially with PGCL and PLGA. However, the expression patterns of the connexin 43 gene were different from the former two genes. Multiple regression analysis revealed a high correlation between cartilage proteoglycans production and expression levels of these three genes.
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PMID:Biodegradable polymers in chondrogenesis of human articular chondrocytes. 1623 35

Poly(epsilon-caprolactone) (PCL 6, 12, and 24 wt %) and titanium (TiO2) organic-inorganic hybrid materials have been synthesized by the sol-gel method from a multicomponent solution containing titanium butoxide, poly(epsilon-caprolactone) (PCL), water, and chloroform (CHCl3). Sodium ampicillin was incorporated in the hybrid material to verify the effect as local controlled drug delivery system. The structure of a hybrid materials interpenetrating network is realized by hydrogen bonds between Ti-OH group (H-donator) in the sol-gel intermediate species and carboxylic group (H-acceptor) in the repeating units of the polymer. The presence of hydrogen bonds between organic/inorganic components of the hybrid materials was proved by FTIR analysis. The morphology of the hybrid materials was studied by scanning electron microscope (SEM). The structure of a molecular level dispersion has been disclosed by atomic force microscope (AFM), pore size distribution and surface measurements. The bioactivity of the synthesized hybrid materials has been showed by the formation of a layer of hydroxyapatite on the surface of TiO2/PCL samples soaked in a fluid simulating the composition of the human blood plasma. The amount of sodium ampicillin released has been detected by UV-vis spectroscopy and SEM. The release kinetics seems to occur in more than one stage. HPLC analysis has also been taken to ensure the integrity of ampicillin after the synthetic treatment.
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PMID:Release kinetics of ampicillin, characterization and bioactivity of TiO2/PCL hybrid materials synthesized by sol-gel processing. 1640 15

Little information was found in the literature about the expression on hydroxyapatite (HA) materials of genes specific of cellular adhesion molecules although more were found on titanium-based substrates. Hence, the goal of this work was to study by a kinetic approach from 30 min to 4 days the adhesion of Saos-2 cells on microporous (mHA) and non-microporous hydroxyapatite (pHA) in comparison to polished titanium. Our strategy associated the visualization of adhesion proteins inside the cells by immunohistochemistry and the quantitative expression of genes at mRNA level by real-time PCR. The cell morphology was assessed using scanning electron microscopy and the number of cells thanks to biochemical techniques. The cellular attachment was the highest on mHA from 30 min to 24 h although the cell growth on mHA was the lowest after 4 days. Generally, the Saos-2 osteoblastic cells morphology on mHA was radically different than on other surfaces with the particularity of the cytoplasmic edge, which appeared un-distinguishable from the surface. The revelation by specific antibodies of proteins of the cytoskeleton (actin) and the focal adhesions (FAK, phosphotyrosine) confirmed that adhesion and spreading were different on the 3 materials. The actin stress fibres were less numerous and shorter on mHA ceramics. Cells had more focal contacts after 4 h on mHA compared to other substrates but less after 24 h. The highest values of total proteins were extracted from mHA at 0.5 and 24 h and from pHA at 1, 4, and 96 h. The alphav and beta1 integrin, actin, FAK, and ERK gene expression were found to be different with adhesion time and with materials. C-jun expression was comparable on mHA, titanium and plastic but was largely higher than on pHA at 0.5 and 1 h. On the contrary, c-fos expression was the highest on pHA after 0.5 h and the lowest after 1h. This difference between c-fos and c-jun expression on pHA after 0.5 h could be related to the fact that these two genes may differ in their signalling pathways. The expression of the alkaline phosphatase gene after 4 days was lower on mHA compared to other materials demonstrating that the microstructure of the mHA ceramic was not favourable to Saos-2 cells differentiation. Finally, it was demonstrated in this study that HA and titanium surfaces influence as well gene expression at early times of adhesion as the synthesis of adhesion proteins but also proliferation and differentiation phases. Indeed, the signal transduction pathways involved in adhesion of Saos-2 cells on HA and titanium were confirmed by the sequential expression of alphav and beta1 integrins, FAK, and ERK genes followed by the expression of c-jun and c-fos genes for proliferation and alkaline phosphatase gene for differentiation.
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PMID:Quantitative kinetic analysis of gene expression during human osteoblastic adhesion on orthopaedic materials. 1642 24

The purpose of this study was to investigate the effect of a 4-MET- and 10-MDP-based primer on the bond strength of two resin cements (SuperBond C&B, Sun Medical; Panavia Fluoro Cement, Kuraray) to titanium (Ti). Ti plates were treated with six experimental primers consisting of, respectively, 10-MDP and 4-MET in concentrations of 0.1, 1 and 10wt%, or were kept untreated (control). The highest tensile bond strength of Panavia Fluoro Cement to Ti was obtained when the Ti surface was pre-treated with 10wt% 10-MDP and was significantly higher than that when a lower concentrated 10-MDP-based primer or any 4-MET-based primer was used. On the contrary, no significant difference in tensile bond strength of SuperBond C&B was found for the untreated and six pre-treated Ti surfaces, although pre-treatment with each 10-MDP-based primer resulted in a higher tensile bond strength as compared to any 4-MET pre-treatment. Altogether, the data obtained strongly suggest that 10-MDP is effective to improve the adhesive performance of resin to titanium.
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PMID:Effect of 4-MET- and 10-MDP-based primers on resin bonding to titanium. 1670 6


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