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)

Silanized chip surfaces provide a reliable substrate for immobilization of oligonucleotides. The ability for rapid and sensitive detection of oligonucleotide surface coverage on these chips is crucial for their wide and effective applications in biotechnology. In this paper, two different silanization procedures were used to covalently bind fluorescent-labeled single-stranded DNA onto silicon dioxide or nitride chip surfaces. Effects of surface functionalization techniques for different surfaces, and immobilization conditions, including buffers and solution ionic strength, on surface probe coverage were investigated, quantifying the endpoint probe density by fluorescent measurement upon digestion with alkaline phosphatase (ALP). Digestion of surface-immobilized oligonuleotides with ALP released the fluorophore-tagged probe fragments back into the solution. The detection of DNA was accomplished by laser-induced fluorescence detection of the solution containing those cleaved fragments. The probe surface density on gold thin film, determined by ALP-digestion, was found to coincide well with that measured using the conventional alkanethiol-based fluorescence-displacement technique for the same system. The developed method has important implications for evaluating the performance of different oligonucleotide immobilization strategies. Also, it has the potential to serve as a sample-thrifty, time saving, and therefore routine tool to realize more realistic, practical quantification of the surface coverage of oligonucleotides immobilized on any solid surfaces.
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PMID:Quantitation of surface coverage of oligonucleotides bound to chip surfaces: a fluorescence-based approach using alkaline phosphatase digestion. 1865 Oct 76

Oligonucleotide chip-based assays can be a sample-thrifty, time-saving, routine tool for evaluation of chemical-induced DNA strand breaks. This article describes a novel approach using an oligonucleotide chip to determine photosensitizer-induced DNA single-strand breaks. Surface coverage of fluorophore-labeled oligonucleotides on silicon dioxide chip surfaces was determined on alkaline phosphatase digestion. Fluorescence maxima (at 520 nm) of the solutions were converted to molar concentrations of the fluorescein-modified oligonucleotide by interpolation from a predetermined standard linear calibration curve. The photosensitizing activity of chlorpromazine and triflupromazine toward DNA single-strand breaks was then studied at different drug doses and also as a function of photoirradiation time. Photoinduced single-strand breaks calculated using the method described here agreed with values predicted by theoretical extrapolation of the single-strand breaks obtained for plasmid DNAs from agarose gel electrophoresis, and thereby indirectly validated the chip-based assays. Under UV irradiation (>or=93.6 kJ/m2) chlorpromazine (>or=0.08 mM) was found to have significant photogenotoxicity. However, triflupromazine did not exhibit any (photo)genotoxicity over the concentration range studied (0.04-0.20mM). The method developed will be useful for quantitative screening of drug genotoxicity in terms of induction of breaks in DNA.
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PMID:Monitoring the (photo)genotoxicity of photosensitizer drugs: direct quantitation of single-strand breaks in deoxyribonucleic acid using an oligonucleotide chip. 1867 73

Cellular activities of human osteoblasts (HOBs) and mesenchymal stem cells (MSCs) on a silicon-releasable scaffold, siloxane-doped poly(lactic acid) and vaterite composite coated with hydroxycarbonate apatite (SPV-H), were estimated using a medium with or without organic factors, such as dexamethasone (Dex) and beta-glycerophosphate (beta-GP), for inducing mineralization or differentiation. As a control, a composite film containing no silicon (denoted by PV-H) was prepared using poly(lactic acid) and vaterite. HOBs cultured on SPV-H formed some agglomerates, bone nodules, after a 21-day culture in a medium without the organic factors, whereas no agglomerate was observed on PV-H. Laser Raman spectra implied that calcium phosphate precipitated in HOBs on the SPV-H. The silicon species in SPV-H stimulated HOBs to mineralization. The culture tests using MSCs show that the level of alkaline phosphatase (ALP) activity in the cells cultured on SPV-H increased during the 21-day culture in a medium without Dex and beta-GP. The level was unchanged in MSCs cultured on PV-H. In the case of supplementing Dex and beta-GP to the medium, the level of ALP activity in MSCs cultured on SPV-H was higher than that on PV-H at all time points during the 21-day culture. The silicon species in SPV-H were regarded to induce and enhance the osteogenic differentiation of MSCs.
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PMID:Stimulation of human mesenchymal stem cells and osteoblasts activities in vitro on silicon-releasable scaffolds. 1868 33

Although dietary silicon (Si) is recognized to be an important factor for the growth and development of bone and connective tissue, its biochemical role has yet to be identified. The predominant Si-containing species in blood and other biofluids is orthosilicic acid, Si(OH)(4). Dimethylsilanediol, (CH(3))(2)Si(OH)(2), is an environmental contaminant that results from decomposition of silicone compounds used in personal hygiene, health care and industrial products. We examined the in vitro effects of both Si species on the survival (colony forming efficiency), proliferation (DNA content), differentiation (alkaline phosphatase activity) and adhesion (relative protein content) of the human osteoblast-like cell lines Saos-2 and hFOB 1.19. Orthosilicic acid yielded a small, dose-dependent decrease in Saos-2 cell survivability up to its 1,700 micromol/L solubility limit, by which point survival was 20% less than that of untreated cells. This negative association, although small, correlated with a reduction in the proliferation and adhesion of Saos-2 cells as well as of hFOB 1.19 and osteoclast-like GCT cells. By contrast, dimethylsilanediol treatment had no discernable influence on Saos-2 survivability at concentrations up to 50 micromol/L, and yet significantly enhanced cell survival at higher doses. Moreover, dimethylsilanediol did not affect proliferation or adhesion of any cell line. The findings show that orthosilicic acid and dimethylsilanediol affect osteoblast-like cells very differently, providing insight into the mechanism by which silicon influences bone health, although the specific site of Si activity remains unknown. There was no evidence to suggest that dimethylsilanediol is cytotoxic at environmental/physiological concentrations.
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PMID:Divergent effects of orthosilicic acid and dimethylsilanediol on cell survival and adhesion in human osteoblast-like cells. 1875 97

The osteoconductive property of titanium (Ti) surfaces is important in orthopedic and dental implant devices. Surface modifications of Ti have been proposed to further improve osseointegration. In this study, three different materials, silicon (Si), silicon oxide (SiO(2)), and titanium oxide (TiO(2)), were used to construct nanofibers for surface coating of Ti alloy Ti-6Al-4 V (Ti alloy). MC3T3-E1 osteoprogenitor cells were seeded on nanofiber-coated discs and cultured for 42 days. DNA, alkaline phosphatase, osteocalcin, and mineralization nodules were measured using PicoGreen, enzyme-linked immunosorbent assay, and calcein blue staining to detect the attachment, proliferation, differentiation, and mineralization of MC3T3-E1 cells, respectively. The results demonstrated that the initial cell attachments on nanofiber-coated discs were significantly lower, although cell proliferation on Si and SiO(2) nanofiber-coated discs was better than on Ti alloy surfaces. TiO(2) nanofibers facilitated a higher cellular differentiation capacity than Ti alloy and tissue culture-treated polystyrene surfaces. Thus, surface modification using nanofibers of various materials can alter the attachment, proliferation, and differentiation of osteoprogenitor cells in vitro.
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PMID:Effect of nanofiber-coated surfaces on the proliferation and differentiation of osteoprogenitors in vitro. 1895 Feb 72

The purpose of this study was to investigate the effect of silicon (Si) supplementation on bone mineral density (BMD) and bone metabolism parameters relative to calcium (Ca) intake levels in ovariectomized rats. A total of 72 female Wistar rats (6 weeks) were ovariectomized (OVX) and divided into six groups, and Si (500 mg of Si per kilogram of feed) was or was not administered with diets containing various levels of Ca (0.1%, 0.5%, and 1.5%) for 10 weeks. The groups were as follows: (1) Ca-deficient group (0.1% Ca), (2) Ca-deficient with Si supplementation group, (3) adequate Ca group (0.5% Ca), (4) adequate Ca with Si supplementation group, (5) high Ca group (1.5% Ca), and (6) high Ca with Si supplementation group. Si supplementation significantly increased the BMD of the femur and tibia in Ca-deficient OVX rats, while no change was observed with Si supplementation in the BMD of the spine, femur, and tibia in the adequate and high Ca groups. Serum alkaline phosphatase and osteocalcin levels were not affected by Si supplementation or Ca intake levels. C-telopeptide type I collagen levels were significantly decreased as a result of Si supplementation in Ca-deficient OVX rats. In summary, Si supplementation produced positive effects on bone mineral density in Ca-deficient OVX rats by reducing bone resorption. Therefore, Si supplementation may also prove to be helpful in preventing osteoporosis in postmenopausal women whose calcium intake is insufficient.
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PMID:Silicon supplementation improves the bone mineral density of calcium-deficient ovariectomized rats by reducing bone resorption. 1903 93

The aim of this study consisted on investigating the influence of silicon substituted hydroxyapatite (Si-HA) coatings over the human osteoblast-like cell line (SaOS-2) behaviour. Diatomaceous earth and silica, together with commercial hydroxyapatite were respectively the silicon and HA sources used to produce the Si-HA coatings. HA coatings with 0 wt% of silicon were used as control of the experiment. Pulsed laser deposition (PLD) was the selected technique to deposit the coatings. The Si-HA thin films were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) demonstrating the efficient transfer of Si to the HA structure. The in vitro cell culture was established to assess the cell attachment, proliferation and osteoblastic activity respectively by, Scanning Electron Microscopy (SEM), DNA and alkaline phosphatase (ALP) quantification. The SEM analysis demonstrated a similar adhesion behaviour of the cells on the tested materials and the maintenance of the typical osteoblastic morphology along the time of culture. The Si-HA coatings did not evidence any type of cytotoxic behaviour when compared with HA coatings. Moreover, both the proliferation rate and osteoblastic activity results showed a slightly better performance on the Si-HA coatings from diatoms than on the Si-HA from silica.
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PMID:Silicon-hydroxyapatite bioactive coatings (Si-HA) from diatomaceous earth and silica. Study of adhesion and proliferation of osteoblast-like cells. 1908 99

Nanocrystalline diamond has been proposed as an anti-abrasive film on orthopedic implants. In this study, osteoblast (bone forming cells) functions including adhesion (up to 4h), proliferation (up to 5 days) and differentiation (up to 21 days) on different diamond film topographies were systematically investigated. In order to exclude interferences from changes in surface chemistry and wettability (energy), diamond films with nanometer and micron scale topographies were fabricated through microwave plasma enhanced chemical-vapor-deposition and hydrogen plasma treatment. Scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy and water contact angle measurements verified the similar surface chemistry and wettability but varied topographies for all of the diamond films prepared on silicon in this study. Cytocompatibility assays demonstrated enhanced osteoblast functions (including adhesion, proliferation, intracellular protein synthesis, alkaline phosphatase activity and extracellular calcium deposition) on nanocrystalline diamond compared to submicron diamond grain size films for all time periods tested up to 21 days. An SEM study of osteoblast attachment helped to explain the topographical impact diamond had on osteoblast functions by showing altered filopodia extensions on the different diamond topographies. In summary, these results provided insights into understanding the role diamond nanotopography had on osteoblast interactions and more importantly, the application of diamond films to improve orthopedic implant lifetimes.
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PMID:The impact of diamond nanocrystallinity on osteoblast functions. 1933 49

Invisible ink and writing secret messages have been part of man's fantasy, having proven useful in clandestine and high sensitivity areas. Security inks, made up of invisible materials that give printed images that cannot be photocopied, that can be read only under special environments have become important. An ink formulation based on silicon (IV) 2,3-naphthalocyanine bis(trihexylsilyloxide) as colorant, invisible to the naked eye but infrared readable, has been described earlier. Biometric DNA ink has also been developed for security authentication. In lighter vein, many budding scientists and others have often experimented with writing secret messages on paper, either for purposes of fun or actually sending secret messages to friends. It involved the use of lemon juice, milk, or other solutions that could be used with a dip pen, brush, or a fountain pen to write invisible messages on a blank white paper. Words turn up as though by magic when the paper is exposed' to heat in one form or the other. Here, an attempt is made to end this book on a slightly humorous note by showing that invisible messages can be written on nitrocellulose membranes (but not on polyvinylidene difluoride membranes) using an appropriately diluted horseradish peroxidase/alkaline phosphatase anti-IgG conjugate (rabbit, mouse, or human anti-IgG). The message is written on the membrane, preferably with a fountain pen, and the membrane is allowed to dry. Regular detection with enhanced chemiluminiscence (ECL) plus or nitro blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate systems is used to unravel the secret message. In addition, this method could be used to mark nitrocellulose membranes for orientation purposes using ECL detection system and thus can eliminate the use of autoradiography pens.
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PMID:Sending secret messages on nitrocellulose membrane and the use of a molecular pen for orientation in ECL membrane assays. 1937 93

The excellent mechanical, tribological and biochemical properties of diamond coatings are promising for improving orthopedic or stomatology implants. A crucial prerequisite for such applications is an understanding and control of the biological response of the diamond coatings. This study concentrates on the correlation of diamond surface properties with osteoblast behavior. Nanocrystalline diamond (NCD) films (grain size up to 200 nm, surface roughness 20 nm) were deposited on silicon substrates of varying roughnesses (1, 270 and 500 nm) and treated by oxygen plasma to generate a hydrophilic surface. Atomic force microscopy was used for topographical characterization of the films. As a reference surface, tissue culture polystyrene (PS) was used. Scanning electron microscopy and immunofluorescence staining was used to visualize cell morphological features as a function of culture time. Metabolic activity, alkaline phosphatase activity, and calcium and phosphate deposition was also monitored. The results show an enhanced osteoblast adhesion as well as increased differentiation (raised alkaline phosphatase activity and mineral deposition) on NCD surfaces (most significantly on RMS 20 nm) compared to PS. This is attributed mainly to the specific surface topography as well as to the biocompatible properties of diamond. Hence the controlled (topographically structured) diamond coating of various substrates is promising for preparation of better implants, which offer faster colonization by specific cells as well as longer-term stability.
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PMID:Nanoscale topography of nanocrystalline diamonds promotes differentiation of osteoblasts. 1943 40


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