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)

The effects of an hydrosoluble fraction of the bovine bone extract Ossopan on cultured murine osteoblasts were assessed in this study. The hydrosoluble fraction from Ossopan, obtained by acid/ethanol extraction, contained significant amounts of TGF-beta 1. Calvariae from new-born rats were cultured for 1 month in synthetic medium (DMEM) supplemented with 10% fetal calf serum to allow cell proliferation; immunocytochemistry studies performed with a rabbit serum raised against alkaline phosphatase indicated that only osteoblasts were present in cell cultures. Using an XTT-based colorimetric cell proliferation assay, we showed that the hydrosoluble fraction of the bovine bone extract dose-dependently reduced the proliferation of cultured osteoblasts. A similar inhibition was obtained with a recombinant TGF-beta 1. Thus, the inhibitory effect of the hydrosoluble fraction of Ossopan on osteoblast proliferation should be due to the cytokines contained in this preparation.
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PMID:[Effects of an hydrosoluble fraction from bovine bone (Ossopan) on murine osteoblasts in culture]. 859 Feb 29

The pineal secretory product melatonin reportedly regulates release of growth hormone in humans and prevents phototherapy-induced hypocalcemia in newborn rats, suggesting that melatonin affects bone metabolism. Little is known about the effects of melatonin on bone in vitro or in vivo. The present study was undertaken to examine whether melatonin acts directly on normal human bone cells (HOB-M cells) and human osteoblastic cell line (SV-HFO cells) to affect osteogenic action in vitro. The effect of melatonin on bone cell proliferation was determined using the 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carbo xanilide (XTT) assay after a 24 hr incubation with melatonin. Melatonin significantly and dose-dependently increased the proliferation in HOB-M cells and SV-HFO cells by 215 +/- 22.1%, and 193 +/- 6.4%), respectively, with a maximal effect at a concentration of 50 microM. To evaluate the effect of melatonin on bone cell differentiation, alkaline phosphatase (ALP) activity, osteocalcin secretion and procollagen type I c-peptide (PICP) production (a measure of type I collagen synthesis) were measured after a 48 hr treatment. While melatonin at micromolar concentrations did not significantly affect either the ALP activity or the osteocalcin secretion, it significantly and dose-dependently increased the PICP production in HOB-M cells and SV-HFO cells by 983 +/- 42.2%, and 139 +/- 4.2%, respectively, with the maximal stimulatory doses between 50 and 100 microM. These results provide new evidence that melatonin stimulates the proliferation and type I collagen synthesis in human bone cells in vitro, suggesting that melatonin may act to stimulate bone formation.
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PMID:Melatonin stimulates proliferation and type I collagen synthesis in human bone cells in vitro. 1049 46

This work presents data on the structure and corrosion resistance of titanium after calcium-ion implantation with a dose of 10(17) Ca+/cm2. The ion energy was 25 keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by XPS and SIMS. The corrosion resistance was examined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells (HDBC) in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both calcium-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by TEM results, the surface layer formed during calcium-ion implantation was amorphous. The results of electrochemical examinations indicate that calcium-ion implantation increases the corrosion resistance, but only under stationary conditions; during anodic polarization the calcium-ion-implanted samples undergo pitting corrosion. The breakdown potential is high (2.7-3 V).
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PMID:Effect of calcium-ion implantation on the corrosion resistance and biocompatibility of titanium. 1143 94

This work presents data on the structure and corrosion resistance of titanium after phosphorus-ion implantation with a dose of 10(17)P/cm2. The ion energy was 25keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The corrosion resistance was examined by electrochemical methods in a simulated body fluid at a temperature of 37 C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both phosphorus-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by transmission electron microscope results, the surface layer formed during phosphorus-ion implantation was amorphous. The results of electrochemical examinations indicate that phosphorus-ion implantation increases the corrosion resistance after short-term as well as long-term exposures.
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PMID:Effect of phosphorus-ion implantation on the corrosion resistance and biocompatibility of titanium. 1209 75

In this study, we introduce a porous composite material, termed "Ecopore", and describe in vitro investigation of the material and its modification with fibronectin. The material is a sintered compound of rutile TiO2 and the volcanic silicate perlite with a macrostructure of interconnecting pores. It is both inexpensive and easy to manufacture. We first investigated Ecopore for corrosion and leaching of elements in physiological saline. The corrosion supernatants did not contain critical concentrations of toxic trace elements. In an in vitro model, human primary osteoblasts (HOB) were cultured directly on Ecopore. HOB grew on the composite as well as on samples of its single constituents, TiO2 and perlite glass, and remained vital, but cellular spreading was less than on tissue culture plastic. The pro-inflammatory cytokines IL-1 and TNF-alpha were below detection limits in HOB culture supernatants, whereas IL-6 was detectable on a low level. To enhance cellular attachment and growth, the surface of the composite was modified by etching, functionalization with aminosilane and coupling of fibronectin. This modification greatly enhanced the spreading of HOB, indicated by vital staining and Sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate (XTT) metabolism assays. HOB grew on the entire visible surface of porous fibronectin-modified composite, expressing alkaline phosphatase, a mature osteoblast marker. We conclude that Ecopore is non-toxic and sustains HOB growth, cellular spreading being improvable by coating with fibronectin. The composite may be usable in the field of bone substitution.
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PMID:In vitro behavior of a porous TiO2/perlite composite and its surface modification with fibronectin. 1560 77

This study is concerned with the effect of dual implantation of calcium and phosphorus upon the structure, corrosion resistance and biocompatibility of titanium. The ions were implanted in sequence, first Ca and then P, both at a dose of 10(17) ions/cm2 at a beam energy of 25 keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the implanted layer was examined by XPS and SIMS. The corrosion resistance was determined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. The biocompatibility tests were performed in vitro in a culture of human-derived bone cells (HDBC) in contact with the tested materials. The viability of the cells was determined by an XTT assay and their activity by the measurements of the alkaline phosphatase activity in contact with implanted and non-implanted titanium samples. The in vitro examinations confirmed that, under the conditions prevailing during the experiments, the biocompatibility of Ca + P ion-implanted titanium was satisfactory. TEM results show that the surface layer formed by the Ca + P implantation is amorphous. The corrosion resistance of titanium, examined by the electrochemical methods, appeared to be increased after the Ca + P ion implantation.
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PMID:Effect of dual ion implantation of calcium and phosphorus on the properties of titanium. 1560 80

It is known that the micromotion between implant and bone inhibits direct bone growth either on or into implant surfaces in vivo. Nevertheless, biocompatibility tests in vitro of biomaterials for bone/implant interfaces are mainly performed under static conditions. This work describes a dynamic, in vitro experimental simulation of the effect of mutual, small-scale implant surface-tissue displacement on adhered cells. Disks of simulated tissue (PVP hydrogel) were subjected to cyclic micromotion ranging from 0 at the center to 1000 microm at the periphery at approximately 13 Hz, relative to biomaterial surfaces or tissue culture polystyrene controls populated with human osteoblasts in standard tissue culture plate wells. The effect of the interfacial micromotion on the number of cells remaining attached was quantitated by XTT assay. The activity level of the remaining cells was determined by an alkaline phosphatase assay, and cell stress was evaluated by nitrogen assay. Significantly more cells (ANOVA) became detached from similarly prepared surfaces of titanium, hydroxyapatite, and alumina compared to the polystyrene control, and detachment from alumina was greater than for the other two materials. The activity of the remaining attached cells was lower as compared to the static (no micromotion) control but not significantly different among the biomaterials. All nitrogen assays were negative, suggesting minimal cell stress occurred. The method is proposed as a useful and discriminating in vitro tool for biocompatibility studies focused on cell adhesion to biomaterials under conditions related to those which exist at the implant/bone interface in vivo, and it allows subsequent studies of the still-viable cells by other methods.
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PMID:Experimental model for observation of micromotion in cell culture. 1565 11

It is known that metallic elements of joint endoprostheses undergo elastic strain due to their mechanical function. This is one of the factors which may be responsible for the loosening of endoprostheses. Since mechanisms involved in it remain unclear, it seems valuable to verify if cells responsible for bone regeneration are affected by a strain of the implant. Our experiment examines the influence of elastic strain applied to Ti6Al4V samples on osteoblasts cultured on their surface in vitro. Human bone-derived cells are observed in contact with metallic plates. Titanium alloy was chosen as a support since it is one of the most commonly used materials for stems in joint endoprostheses. Cyclic elastic deformation of 0.1% was applied to the support once daily for 7 days. Two thousand cycles were applied each time. Samples which were not subject to strain served as control. After the observation period XTT assay was performed, alkaline phosphatase activity as well as osteocalcin concentration and nitric oxide secretion were determined and compared with the results obtained in the control group. It was found that the number of viable cells in the mechanically stimulated population was significantly higher than in control, while both alkaline phosphatase activity and osteocalcin concentration were significantly lower in the experimental group. Nitric oxide secretion was found in the culture which was subject to elastic strain, but not in the control. The possible clinical implication is that elastic strain of the metallic endoprostheses may influence osteoblasts which are in contact with the implant in vivo.
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PMID:Osteoblast response to the elastic strain of metallic support. 1661 73

Hydroxyapatite (HA) microparticles as a carrier in an injectable tissue-engineered bone filler are considered promising candidates for the treatment of small bone defects in the craniomaxillofacial region. HA granules calcified from red algae, varying in size, were evaluated in vitro for their suitability to be used as a carrier for human mesenchymal stem cells (hMSCs). Three groups of granules were produced in grain sizes of 10-100, 200-500 and 600-1,000 mum. After seeding and culturing hMSCs under osteogenic differentiation conditions onto HA particles for 3, 6 and 9 days, cellular proliferation (tetrazolium salt, XTT), alkaline phosphatase (ALP)-specific activity and total protein synthesis were investigated. The osteoblastic phenotype of the cells was evaluated by assaying the bone-specific genes osteocalcin, osteopontin and collagen type I. XTT assay revealed significantly higher (p < 0.01) proliferation of cells grown on the smallest grain size after 9 days of culture. Regarding ALP-specific activity, significantly higher levels of activity were detected in cells grown on the smallest grain size. Different grain sizes had no significant effects on the secretion of osteocalcin and osteopontin. Collagen type I production was significantly higher (p < 0.05) in cells grown on the biggest grain size in comparison with the two other grain sizes. These results show that the particle size of HA microparticles affects the osteogenic potential of cultured hMSCs and lead to the conclusion that particle size has differential effects on ALP-specific activity and collagen type I production.
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PMID:Particle size of hydroxyapatite granules calcified from red algae affects the osteogenic potential of human mesenchymal stem cells in vitro. 1680 98

The purpose of this study was to investigate the potential of Mesenchymal Stem Cells (MSCs) obtained from patients suffering from fractures to proliferate and differentiate towards osteogenic lineage with the use of autologous serum. In addition the effect of medium supplementation with the use of autologous serum obtained at different time points (patients' admission, first, third and seventh post-operative day) was investigated. In total eight patients suffering from lower limb long bone fractures with mean age of 39 (range 22-68 years) were included in this study. MSCs were isolated and cultivated in 10% of either Fetal Calf Serum (FCS) or autologous serum. Cellular proliferation was examined by XTT assay and Vybrant assay. The osteogenic differentiation was assessed by total calcium production and alkaline phosphatase production. Cellular proliferation and osteogenic differentiation was significantly statistically higher in patients' serum obtained on admission than in FCS. A negative effect on proliferation was noted with serum obtained on the first postoperative day. Subsequently, both proliferation and differentiation were gradually increased with autologous serum collected during the 3rd and 7th postoperatively days. Autologous serum obtained after fracture is superior in terms of proliferation and osteogenic differentiation to the currently used FCS. Surgery seems to have a negative effect on the quality of serum. These findings should be considered in cases where ex-vivo expansion of MSCs is needed. Recuperation of serum's quality takes place at a later time point within the first weeks after fracture.
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PMID:The effect of autologous serum obtained after fracture on the proliferation and osteogenic differentiation of mesenchymal stem cells. 1895 49


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