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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three different microstructures were obtained on a titanium surface via immersion in HCl, H3PO4, or mixed acid of HNO3 and HF (HNO3/HF) solution. The microstructure and Rmax of the acid-treated surfaces were dependent on the acid type and immersion conditions. The growth rate of the osteogenic cell line MC3T3-E1 on each acid-treated sample, which was measured using MTT-formazan assay, was significantly higher than that of the standard which was ground with #400 SiC grit paper. Moreover, both the H3PO4 treated sample and the HNO3/HF-treated surface showed a tendency to enhance the alkaline phosphatase activity of MC3T3-E1 cells, which were grown on each acid-treated surface. These results suggest that the acid treatment of titanium is effective for the improvement of its osteocompatibility.
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PMID:Effect of microstructure of titanium surface on the behaviour of osteogenic cell line MC3T3-E1. 1534 15

Microtextured titanium implant surfaces enhance bone formation in vivo and osteoblast phenotypic expression in vitro, but the mechanisms are not understood. To determine the roles of specific microarchitectural features in modulating osteoblast behavior, we used Ti surfaces prepared by electrochemical micromachining as substrates for MG63 osteoblast-like cell culture. Cell response was compared to tissue culture plastic, a sand-blasted with large grit and acid-etched surface with defined mixed microtopography (SLA), polished Ti surfaces, and polished surfaces electrochemically machined through a photoresist pattern to produce cavities with 100, 30 and 10 microm diameters arranged so that the ratio of the microscopic-scale area of the cavities versus the microscopic-scale area of the flat region between the cavities was equal to 1 or 6. Microstructured disks were acid-etched, producing overall sub-micron-scale roughness (Ra=0.7 microm). Cell number, differentiation (alkaline phosphatase; osteocalcin) and local factor levels (TGF-beta1; PGE(2)) varied with microarchitecture. 100 microm cavities favored osteoblast attachment and growth, the sub-micron-scale etch enhanced differentiation and TGF-beta1 production, whereas PGE(2) depended on cavity dimensions but not the sub-micron-scale roughness.
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PMID:Differential regulation of osteoblasts by substrate microstructural features. 1557 58

Cell-titanium interactions are crucial to the clinical success of bone and dental implants. The physico-chemical characteristics of the substrates surface influence osteoblast proliferation, differentiation, and activity as well. The osteoblast behavior was analyzed on three different titanium surfaces: ground with an abrasive 600 grit SiC paper, blasted with alumina particles (65 microm diameter) and alumina blasted followed by a double chemical etch (4% HF+4% HF/8% H2O2). Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Ground samples showed parallel-groove orientation. The Al2O3-blasted surface presented the roughest microtopography with aluminum-rich particles incrusted in the titanium surface. Osteoblasts cells from femora of Balb/c mice were seeded onto the substrates tested. Cell morphology and initial attachment were evaluated by SEM. Osteoblasts adhered to and spread on all samples tested. However, on rough surfaces, osteoblasts did not spread completely and acquired a polygonal morphology. Besides, the cell proliferation rate was diminished at the beginning of incubation on rough surfaces. Our results suggest a delay, rather than an impairment, in osteoblast viability and alkaline phosphatase activity when cells are cultured on rough surfaces, inducing a distinct osteoblast phenotype, rather than blocking its activity. At least in the culture conditions used in this work, alumina particles did not affect osteoblast behavior.
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PMID:Effect of three distinct treatments of titanium surface on osteoblast attachment, proliferation, and differentiation. 1630 73

The effectiveness of two amendments for the in situ remediation of a Cd- and Ni-contaminated soil in the Louis Fargue long-term field experiment was assessed. In April 1995, one replicate plot (S1) was amended with 5% w/w of beringite (B), a coal fly ash (treatment S1+B), and a second plot with 1% w/w zerovalent-Fe iron grit (SS) (treatment S1+SS), with the aim of increasing metal sorption and attenuating metal impacts. Long-term responses of daily respiration rates, microbial biomass, bacterial species richness and the activities of key soil enzymes (acid and alkaline phosphatase, arylsulfatase, beta-glucosidase, urease and protease activities) were studied in relation to soil metal extractability. Seven years after initial amendments, the labile fractions of Cd and Ni in both the S1+B and S1+SS soils were reduced to various extents depending on the metal and fractions considered. The soil microbial biomass and respiration rate were not affected by metal contamination and amendments in the S1+B and S1+SS soils, whereas the activity of different soil enzymes was restored. The SS treatment was more effective in reducing labile pools of Cd and Ni and led to a greater recovery of soil enzyme activities than the B treatment. Bacterial species richness in the S1 soil did not alter with either treatment. It was concluded that monitoring of the composition and activity of the soil microbial community is important in evaluating the effectiveness of soil remediation practices.
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PMID:Biochemical parameters and bacterial species richness in soils contaminated by sludge-borne metals and remediated with inorganic soil amendments. 1651 62

The aim of this study was to evaluate the osteogenic properties of magnetron sputtered dicalcium pyrophaosphate (DCPP) and hydroxylapatite (HA) coatings. Therefore, DCPP and HA coatings were deposited on grit-blasted titanium discs. The substrates were used as-prepared or received an additional heat treatment which changed the amorphous coating structure to a crystalline structure. Subsequently, rat bone marrow stromal cells were cultured for 1-24 days on the various substrates. DNA and alkaline phosphatase activity was determined after 1, 3, 5, 8, and 12 days of incubation. Osteocalcin expression was evaluated after 8, 12, 16, and 24 days of incubation. Scanning electron microscopical analysis of cell morphology and coating characteristics was done after 8 and 16 days of incubation. All assays were done in duplicate and in each assay all specimens were present in fourfold. Results demonstrated that the cells did not proliferate and differentiate on all amorphous coatings. SEM revealed that the amorphous coatings showed significant dissolution. On the crystalline DCPP and HA coatings an increase in DNA and alkaline phosphatase activity was seen starting at day 8 of incubation. Osteocalcin expression on the crystalline coatings started to increase at day 16 of incubation. SEM showed that the growth and differentiation of the cells was associated with extensive collagen fiber formation and surface mineralization in the form of globular accretions. Further, statistical testing revealed that proliferation and differentiation of the rat bone marrow stromal cells started significantly earlier on the crystalline HA coatings than that on the crystalline DCPP coatings. These results demonstrate that the rat bone marrow stromal cells proliferated and differentiated only on crystalline magnetron sputtered DCPP as well as HA coatings, which warrants the further in vivo analysis of the bone healing supporting properties of these coatings.
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PMID:Growth behavior of rat bone marrow cells on RF magnetron sputtered hydroxyapatite and dicalcium pyrophosphate coatings. 1660 22

Integrin alpha(5)beta(1) regulates osteoblast proliferation and differentiation on smooth synthetic surfaces presenting different chemistries, but it is not known whether this integrin controls osteoblast behavior on surfaces that have micron-scale rough topographies. We cultured MG63 human osteoblast-like cells on titanium substrates with three different roughness characteristics: chemically polished (PT), grit blasted and acid etched with a complex topography consisting of 20-100 mum craters and 0.5-2 mum micropits (SLA), and plasma-sprayed Ti with irregular projections (TPS). Cells spread well on PT but displayed a smaller footprint on SLA or TPS. Nuclei were larger on PT as well. alpha(5)beta(1) binding and FAK phosphorylation were greater on the rougher surfaces (TPS > SLA > PT). Antibodies against the alpha(5)beta(1) binding site on fibronectin had no effect on cell number at 3 days, but [(3)H]-thymidine incorporation was increased, suggesting that binding to fibronectin was necessary for cell cycle regulation. Antibodies to the alpha(5) subunit reduced cell number at 3 days on PT and TPS and reduced DNA synthesis on all substrates in a surface microstructure-independent manner. At 7 days, cell numbers were reduced on PT, and DNA synthesis was reduced by 50% on all surfaces. At 7 days, anti-alpha(5) antibodies caused a partial reduction in alkaline phosphatase enzyme activity on all surfaces, but this effect was independent of surface microstructure. These results indicate that surface micron-scale topography modulates alpha(5)beta(1) integrin binding and FAK activation. Signaling via alpha(5)-dependent mechanisms is required for DNA synthesis and regulation of alkaline phosphatase, but this effect is independent of surface microstructure.
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PMID:Integrin alpha(5) controls osteoblastic proliferation and differentiation responses to titanium substrates presenting different roughness characteristics in a roughness independent manner. 1713 43

The aim of this study was to investigate the influence of hydrophobic acid-etched (A) and coarse-blasted large-grit and acid-etched (SLA) surfaces as well as hydrophilic modified acid-etched (modA) and modified coarse-blasted large-grit and acid-etched (modSLA) surfaces on the behavior of MG63 cells grown on these surfaces through determination of cell attachment and cell proliferation, time-lapse microscopy of fluorescence-labeled cells, and determination of gene expression by reverse transcription-polymerase chain reaction (RT-PCR). No significant difference of cell attachment on various titanium surfaces was found. Increased cell proliferation was observed on the A surface and the SLA surface compared with the modA surface and the modSLA surface. After 2 days of incubation, on modSLA and modA surfaces a tendency of formation of cell clusters has been observed, which was most pronounced on modSLA surface. On the A and the SLA surface, cell cluster formation started after longer incubation periods. The expression level of the bone-associated genes (alkaline phosphatase, osteocalcin, type-I-collagen, osteoprotegerin, and glyceraldehyde-3-phosphate-dehydrogenase) detected by RT-PCR was highest on the modSLA surface. In conclusion it has been demonstrated that the modSLA surface results in an enhanced cluster formation of osteoblasts grown on this surface and in an increased expression of key osteogenic regulatory genes in osteoblasts.
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PMID:The initial attachment and subsequent behavior regulation of osteoblasts by dental implant surface modification. 1732 17

It is widely accepted that implant surface factors affect the quality of the bone-to-implant interface. Recent additional treatments superimposed on moderately rough cpTitanium surface provide further enhancement of bone-to-implant contact. The aim of this study was to compare osteoinductive and bone-specific gene expression in cells adherent to titanium dioxide-grit blasted (TiO2) versus TiO2 grit blasted and HF treated (TiO2/HF) cpTitanium implant surfaces. MC3T3-E1 cells were grown in osteogenic supplements on the titanium disk surfaces for 1-14 days. Real-time PCR was used to measure RUNX-2, Osterix, and bone sialoprotein (BSP) mRNA levels. Implants were placed in rat tibia and, following harvesting at 1-7 days after placement, real-time PCR was used to measure RUNX-2, alkaline phosphatase (ALP), and BSP mRNA levels in implant adherent cells. In cell culture, RUNX-2 and Osterix levels were significantly increased (p<0.05) on the TiO2/HF surfaces as compared to the TiO2 and smooth surfaces through the cultural period, while BSP expression was elevated on both TiO2 and TiO2/HF surfaces when compared to a machined surface control. In cells adherent to implants retrieved from rat tibia, RUNX-2 mRNA levels were 2-fold and 8-fold greater on the TiO2/HF surfaces at 1-3 and 7 days following implantation. This was paralleled by significantly greater levels of ALP at 3 and 7 days and BSP mRNA at 7 days following implantation. As a marker of osteoinduction, the increased levels of RUNX-2 in cells adherent to the TiO2/HF surfaces suggest that the additional HF treatment of the TiO2 grit blasted surface results in surface properties that support adherent cell osteoinduction. In vivo assessments of implant adherent cell phenotypes provide further insight into the mechanisms affecting alloplast-tissue interactions.
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PMID:The effect of hydrofluoric acid treatment of TiO2 grit blasted titanium implants on adherent osteoblast gene expression in vitro and in vivo. 1786 50

The surface characteristics of a calcium ion (Ca)-incorporated titanium (Ti) surface, produced by hydrothermal treatment using an alkaline Ca-containing solution, and its effects on osteoblastic differentiation were investigated. MC3T3-E1 pre-osteoblastic cells were cultured on machined or grit-blasted Ti surfaces with and without Ca incorporation. The MTT assay was used to determine cell proliferation, and real-time PCR was used for quantitative analysis of osteoblastic gene expression. Hydrothermal treatment with a Ca-containing solution produced a crystalline CaTiO(3) nanostructure of approximately 100 nm in dimension, preserving original micron-scaled surface topographies and microroughness caused by machining, blasting, or blasting and etching treatments. After immersion in Hank's balanced salt solution, considerable apatite formation was observed on all surfaces of the Ca-incorporated samples. Significantly more cell proliferation was found on Ca-incorporated Ti surfaces than on untreated Ti surfaces (p < 0.001). Quantitative real-time PCR analysis showed notably higher alkaline phosphatase, osteopontin, and osteocalcin mRNA levels in cells grown on Ca-incorporated blasted surfaces than on other surfaces at an early time point. Thus, Ca incorporation may have a beneficial effect on osseointegration of microstructured Ti implants by accelerating osteoblast proliferation and differentiation during the early healing phase following implantation.
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PMID:Effects of calcium ion incorporation on osteoblast gene expression in MC3T3-E1 cells cultured on microstructured titanium surfaces. 1794 Oct 22

Increased magnitude of biomaterial surface roughness and micromachined-grooved surfaces has both been shown to stimulate osteoblast activity, but have not been compared in the same study quantitatively. A series of titanium alloy (Ti6Al4V) samples were prepared using simple machining techniques to undertake such a comparison. Samples were either grit blasted (Gb) or shot peened (Sp) to give random discontinuities, or silicon carbide ground (SiC) to produce ordered grooves. These were compared with micropolished samples (Mp). The samples were coated with a 1 mum continuous coating of hydroxyapatite to remove differences in surface chemistry. Human osteoblast-like cells were seeded onto the materials and metabolic activity, proliferation, alkaline phosphatase activity, and osteocalcin production assessed. Cell responses were highly dependent on the substrate that they were cultured on. Cells cultured on the smooth and ordered (Mp and SiC, respectively) samples had higher metabolic activity and a more elongated morphology than those cultured on the randomly structured Gb or Sp samples. Over 21 days, cell metabolic activity peaked relative to the control between 7 and 14 days on the Mp sample, and between 14 and 21 days on the Gb, Sp, and SiC samples. In common with other researchers, we note that micron scale topography may have potential for influencing osseointegration. More importantly, as the magnitude of the discontinuities on SiC, Gb, and Sp were similar, the differences in cell responses does not appear to lie with the size of the features, but whether the features showed an ordered or disordered structure.
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PMID:The effect of different surface morphology and roughness on osteoblast-like cells. 1802


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