Topic
Alkaline phosphatase
About: Alkaline phosphatase is a research topic. Over the lifetime, 20218 publications have been published within this topic receiving 540547 citations. The topic is also known as: Alkaline_phosphatase & IPR001952.
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TL;DR: Overall comparison of active sites of dPGM, Fru26P2ase, and AcPase is 273, which indicates that catalysis of the S. cerevisiae d PGM is mainly concerned with phosphoglycerate mutase-related reactions.
Abstract: 2. Cofactor dependent Saccharomyces cerevisiae phosphoglycerate mutase . . . . . . . . . . . . . . . . 265 2.1. Structural aspects of Saccharomyces cerevisiae phosphoglycerate mutase . . . . . . . . . . 265 2.2. Mechanism of catalysis of the S. cerevisiae dPGM . . . . . . . . . . . . . . . . . . . . . . . . . . 270 2.3. Structural comparison of dPGM with other enzymes . . . . . . . . . . . . . . . . . . . . . . . . 270 2.3.1. Structural comparison of S. cerevisiae dPGM with 6-phosphofructo-2-kinase/ fructose-2,6-bisphosphatase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 2.3.2. Structural comparison of S. cerevisiae dPGM with acid phosphatase . . . . . . . 272 2.3.3. Overall comparison of active sites of dPGM, Fru26P2ase, and AcPase . . . . . 273
140 citations
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TL;DR: The simultaneous time-course of appearance of increased levels of brush border alkaline phosphatase and the increased rate of transport of calcium, measured in vivo across intact segments of ileal tissue after oral vitamin D3 administration, suggests a functional involvement of alkalineosphatase in vitamin D-mediated calcium transport.
140 citations
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TL;DR: New mechanisms whereby an acute stress acts on the gastrointestinal tract are highlighted by inducing alterations in colonocyte differentiation and decreased expression of mRNA encoding tight junction proteins, which pave the way for stress related intestinal disorders.
Abstract: Background and aim: Stressful life events are known to modulate the development or relapse of disease in both inflammatory bowel disease and irritable bowel disease patients but underlying mechanisms remain unclear. Stress is known to effect mast cells, interferon γ (IFN-γ), and myosin light chain phosphorylation to trigger colonic epithelial barrier dysfunction. The aim of this study was to investigate whether acute stress induced or chemical mast cell activation impaired expression and function of epithelial tight junctions, and altered colonocyte differentiation in mice. Methods: Colonic paracellular permeability was assessed as the in vivo lumen to blood ratio of 51 Cr-EDTA in different groups of mice (controls, stressed, mast cell degranulator BrX-537A treated), pretreated or not with the mast cell stabiliser doxantrazole. Involvement of mast cells and IFN-γ was evaluated in wild-type and IFN-γ deficient mice. Tight junction alteration was assessed by histology, transmission electron microscopy, and real time reverse transcription-polymerase chain reaction. Colonocyte differentiation was determined by protein kinase C ζ (PKCζ) immunofluorescence and western blotting, and alkaline phosphatase activity assay. Results: Acute stress induced a three day delayed increase in colonic paracellular permeability which involved mast cell degranulation and overproduction of IFN-γ. The colonic epithelial barrier was morphologically altered and expression of mRNA encoding tight junction proteins ZO-2 and occludin was decreased. Moreover, three days after acute stress, colonocyte differentiation was reduced, as shown by decreased expression of both PKCζ isotype and alkaline phosphatase. Conclusion: These data highlight new mechanisms whereby an acute stress acts on the gastrointestinal tract by inducing alterations in colonocyte differentiation and decreased expression of mRNA encoding tight junction proteins. Thus phenotypic changes in colonocytes could pave the way for stress related intestinal disorders.
139 citations
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TL;DR: Small shifts in extracellular pH led to significant changes in the ability of BMSCs to express markers of the osteoblast phenotype and suggest that degrading polymer scaffolds may influence the biologic activity of the cells in the immediate environment.
Abstract: The objective of this study was to address the hypothesis that changes in extracellular pH alter collagen gene expression, collagen synthesis, and alkaline phospha- tase activity in bone marrow stromal cells (BMSCs). Poten- tial effects of pH on cell function are of particular impor- tance for tissue engineering because considerable effort is being placed on engineering biodegradable polymers that may generate a local acidic microenvironment on degrada- tion. Human and murine single-cell marrow suspensions were plated at a density o f2×1 0 4 cells/cm 2 . After 7 days in culture, the pH of the culture medium was adjusted to one of six ranges: 7.8, 7.5.-7.7, 7.2-7.4, 6.9-7.1, 6.6-6.8, or 6.5. After 48 h of exposure to an altered pH, alkaline phospha- tase activity and collagen synthesis decreased significantly with decreasing pH. This decrease was two-to threefold as pH decreased from 7.5 to 6.6. In contrast, 1(I) procollagen mRNA levels increased two- to threefold as pH was de- creased. The trend in osteocalcin mRNA expression was op- posite to that of collagen. Small shifts in extracellular pH led to significant changes in the ability of BMSCs to express markers of the osteoblast phenotype. These pH effects po- tentially relate to the microenvironment supplied by a tis- sue-engineering scaffold and suggest that degrading poly- mer scaffolds may influence the biologic activity of the cells in the immediate environment. © 2002 John Wiley & Sons, Inc. J Biomed Mater Res 60: 292-299, 2002; DOI 10.1002/ jbm.10050
139 citations
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TL;DR: It is thought that low intensity pulsed ultrasound stimulated periosteal cell proliferation and differentiation toward osteogenic lineage and the dose-dependent effect on osteogenic activities may modify the existing treatment regimen.
Abstract: The effect of low intensity pulsed ultrasound on human periosteal cells was investigated. Normal human periosteum was obtained to culture the periosteal cells. After characterization, cultures of periosteal cells at Days 2 and 4 were treated with ultrasound for 5, 10, and 20 minutes respectively. Assessments were done to assess total number of viable cells, cell proliferation, alkaline phosphatase activity, osteocalcin secretion, vascular endothelial growth factor expression, and calcium nodule formation. With the cells not treated with ultrasound as the control, the results showed that ultrasound did not affect the total number of viable cells. It stimulated cell proliferation at the early phase of cell culture. The activity of alkaline phosphatase was increased significantly in the culture at Day 4. A similar effect was seen with osteocalcin secretion and the responses were dose-dependent. The vascular endothelial growth factor secretion increased in Day 2 and Day 4 cultures with the dose-dependent effect. Formation of calcium nodules was significantly higher with ultrasound treatment. We think that low intensity pulsed ultrasound stimulated periosteal cell proliferation and differentiation toward osteogenic lineage. The dose-dependent effect on osteogenic activities may modify the existing treatment regimen. Ultrasound treatment should be started from the beginning of fracture healing.
139 citations