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

---

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

A nonisotopic and quantitative in situ hybridization technique was adapted to investigate the effect of biomaterials on the cellular expression of mRNA from human bone derived cells (HBD cells). HBD cells were cultured for 24 or 48 h on tissue culture plastic, alumina, and ion modified alumina. Osteocalcin, osteopontin, alkaline phosphatase, type I collagen alpha 1, and type I collagen alpha 2 mRNAs were quantified. Protein expression for collagen types I, III, and V, and for anti-human macrophages CD68 (DAKO-CD68, KP1) and CD68 (PG-M1), and anti-human myeloid/histiocyte antigen (DAKO-MAC 387) were determined immunohistochemically using monoclonal antibodies. At 24 and 48 h, levels of mRNA for alkaline phosphatase and osteonectin were greater than mRNA levels for osteopontin, osteocalcin, collagen type I alpha 1, and collagen type I alpha 2 for cells grown on the three substrata. However, at 48 h mRNA levels for alkaline phosphatase and osteonectin were significantly higher on the modified ceramic substrata relative to the native alumina. HBD cells appear to express CD68-KP1 when cultured for 24 h. The techniques provide a sensitive and reproducible assay to evaluate gene and protein expression of cells grown on different substrata.
...
PMID:A novel technique for quantitative detection of mRNA expression in human bone derived cells cultured on biomaterials. 895 88

We have determined the age-related changes in the growth characteristics and expression of the osteoblast phenotype in human calvaria osteoblastic cells in relation with histologic indices of bone formation during postnatal calvaria osteogenesis. Histomorphometric analysis of normal calvaria samples obtained from 36 children, aged 3 to 18 months, showed an age-related decrease in the extent of bone surface covered with osteoblasts and newly synthesized collagen, demonstrating a progressive decline in bone formation during postnatal calvaria osteogenesis. Immunohistochemical analysis showed expression of type I collagen, bone sialoprotein, and osteonectin in the matrix and osteoblasts, with no apparent age-related change during postnatal calvaria osteogenesis. Cells isolated from human calvaria displayed characteristics of the osteoblast phenotype including alkaline phosphatase (ALP) activity, osteocalcin (OC) production, expression of bone matrix proteins, and responsiveness to calciotropic hormones. The growth of human calvaria osteoblastic cells was high at 3 months of age and decreased with age, as assessed by (3H)-thymidine incorporation into DNA. Thus, the age-related decrease in bone formation is associated with a decline in osteoblastic cell proliferation during human calvaria osteogenesis. In contrast, ALP activity and OC production increased with age in basal conditions and in response to 1,25(OH)2 vitamin D3, suggesting a reciprocal relationship between cell growth and expression of phenotypic markers during human postnatal osteogenesis. Finally, we found that human calvaria osteoblastic cells isolated from young individuals with high bone formation activity in vivo and high growth potential in vitro had the ability to form calcified nodular bone-like structures in vitro in the presence of ascorbic acid and beta-glycerophosphate, providing a new model to study human osteogenesis in vitro.
...
PMID:Age-related changes in bone formation, osteoblastic cell proliferation, and differentiation during postnatal osteogenesis in human calvaria. 901 61

We established bone marrow stromal cell lines from a transgenic mouse that harbors a temperature-sensitive mutant of the simian virus 40-derived large T-antigen under the control of a major histocompatibility complex (MHC) I promotor. These cell lines were screened for their ability to induce the formation of osteoclasts in a spleen cell/stromal cell coculture system. By means of this screen, five clones, referred to as marine bone marrow stromal clone 1 (mBMS-B1) mBMS-B2, mBMS-B14, mBMS-B18, and mBMS-B21, were selected for detailed characterization. Cell growth depends on culture conditions, i.e., cells grow at 33 degrees C in the presence of murine interferon-gamma, whereas cell proliferation ceases at 39 degrees C. The phenotype of the cells is also correlated with the culture conditions because the osteoclast inductive capacity is only seen at 39 degrees C, indicating that the cells undergo differentiation when the transforming agent is inactivated. These conditionally immortalized stromal cells can be induced to express a variety of markers that are typical for mature osteoblasts, e.g., alkaline phosphatase activity and expression of functional parathyroid hormone receptor after stimulation with soluble osteogenic protein 1 (sOP-1). mRNA analysis revealed the expression and regulation of osteopontin, osteonectin, and collagen alpha 1(I) as well as the inducibility of osteocalcin upon treatment with sOP-1. The cells have the potential to form mineralized nodules in supplemented medium. We observed expression of vascular cell adhesion molecule-1, which is stimulated upon treatment of the cells with 1 alpha,25-dihydrocholecalciferol after 4 days, indicating the presence of the receptor for this steroid. These cell lines represent a model to study mechanisms and factors involved in osteoblast differentiation.
...
PMID:Establishment and characterization of conditionally immortalized stromal cell lines from a temperature-sensitive T-Ag transgenic mouse. 904 Oct 49

We have investigated the early cellular events that take place during the phenotypic switch from hypertrophic chondrocytes to bone-forming cells in a) chondrocytes located inside intact lacunae after embryonic chick femurs had been cut through the hypertrophic cartilage and cultured for 1-15 days; and b) at the cartilage/marrow interface of femurs after short-term culture. Ultrastructural studies were combined with in situ methods localizing proliferating and apoptotic cells, and 3D-reconstructions of confocal images of the cartilage/marrow edge. The crucial event in the phenotypic switch was an asymmetric cell division which resulted in one daughter cell which underwent apoptosis and another viable daughter cell which subsequently differentiated to an osteogenic cell, i.e to a smaller basophilic cell that was positive for alkaline phosphatase, type I collagen, osteonectin, osteopontin, bone sialoprotein and osteocalcin and that, after 12-15 days in culture, could synthesize a mineralized bone matrix within intact lacunae. The present results suggest a mechanism whereby differentiated cells can change their phenotype. At least one mitotic division seems to be required to fix the commitment to the new phenotype.
...
PMID:The phenotypic switch from chondrocytes to bone-forming cells involves asymmetric cell division and apoptosis. 908 46

We investigated the expression of osteocalcin (OC), bone sialoprotein (BSP), osteonectin (ON), and alkaline phosphatase (ALP) during cell differentiation and bone nodule formation by fetal rat calvaria cells, using immunofluorescent and immunogold techniques at light and electron microscopic levels. Six hours after plating all proteins were expressed in calvaria cells. However, expression was not detected during the proliferation phase after plating. Cell morphological modifications were observed in osteoblastic cells expressing ALP, OC, and BSP, but not ON. During the matrix formation phase, all proteins were expressed with various intensities and OC was limited to differentiated osteoblastic cells. EM observations demonstrated that BSP was selectively associated with clusters of needle-like crystals, but not with collagen fibers, in mineralization foci and in the mineralized matrix. OC was localized intracellularly and in all the extracellular compartments, and was concentrated at the mineralization front. ON was distributed uniformly throughout the osteoid and mineralized matrix, which was intensely labeled. The results show that the expression of bone matrix proteins during differentiation of calvaria cells and nodule formation in vitro duplicate what is observed during osteogenesis in vivo.
...
PMID:Sequential expression of bone matrix proteins during rat calvaria osteoblast differentiation and bone nodule formation in vitro. 911 Dec 28

We have recently established a human osteoblastic cell line (SV-HFO) in a culture system, in which the cells are mineralized by treatment with dexamethasone (Dex). Using this system, we examined the effects of all trans-retinoic acid (RA) on the mineralization of the cells. RA inhibited the mineralization, coincident with the inhibition of alkaline phosphatase (ALP). On the other hand, RA induced osteocalcin secretion and had no effect on the expression of the other osteoblastic markers such as type I collagen and osteonectin. To further clarify the mechanism of inhibition of mineralization by RA, we used the retinoic acid receptor (RAR) alpha-selective (Am80), beta-selective (CD2019) and gamma-selective (CD437) agonists instead of RA. RAR alpha- and RAR beta-selective agonists inhibited the mineralization and ALP activity of the cells, while the RAR gamma-selective agonist had no such effects. On the other hand, the RAR gamma-selective agonist induced osteocalcin secretion, but RAR alpha- and RAR beta-selective agonists had no effect on osteocalcin secretion. These results suggested that the inhibitory effect of RA on the mineralization of human osteoblasts is mediated by the activation of RAR alpha and/or RAR beta and that RAR gamma preferentially regulates the expression of osteocalcin without influence on mineralization.
...
PMID:All-trans retinoic acid inhibits dexamethasone-induced ALP activity and mineralization in human osteoblastic cell line SV HFO. 911 87

A neoplastic clonal cell line, which was prepared by 5-azacytidine treatment of a neoplastic human salivary intercalated duct cell line, was cultivated in the presence of 22-oxa-1alpha, 25-dihydroxyvitamin D3 and 3 mM beta-glycerophosphate. Major alterations, such as expression of type I collagen and alkaline phosphatase as well as of human osteopontin and osteonectin, were observed in these cells with a phenotype similar to osteoblasts. In addition, formation of bone nodule was observed in the cultured cells. The tumors produced by transplantation into nude mice of the clonal cells were treated with 22-oxa-1alpha, 25-dihydroxyvitamin D3 and examined for tumor growth and morphology. Consequently, growth of the treated tumor was significantly suppressed. Moreover, it was found that bone formation was induced in the treated tumor, in which the tumor cells around bone formation expressed human osteopontin and osteonectin mRNA as could be detected by in situ hybridization. The above findings indicate that the emergence of osteoblast-like cells in the human salivary cancer cells occurs in the presence of 22-oxa-1alpha, 25-dihydroxyvitamin D3 and beta-glycerophosphate.
...
PMID:Emergence of osteoblast-like cells in a neoplastic human salivary cancer cell line after treatment with 22-oxa-1alpha, 25-dihydroxyvitamin D3. 914 18

Periodontal regeneration is a complex process that requires coordinated responses from several cell types within the periodontium. It is generally accepted that the periodontal ligament (PDL) has a heterogeneous cell population, where some of the cells may be capable of differentiating into either cementoblasts or osteoblasts. Thus, it has been hypothesized that PDL cells play a role in promoting periodontal regeneration. However, definitive evidence to support this concept is lacking. Previously, we reported that PDL cells induce biomineralization as determined by Von Kossa histochemistry and transmission electron microscopy. To further determine the osteoblast-like properties of PDL cells, human PDL cells were exposed to dexamethasone (DEX) in order to promote an osteoblast phenotype, and then cell activity monitored during mineral nodule formation in vitro. For mineralization studies, cells were cultured in DMEM containing 10% FBS and a) vehicle only; b) ascorbic acid (50 micrograms/ml) and beta-glycerophosphate (10 mM); or c) ascorbic acid, beta-glycerophosphate and DEX (100 nM) for 30 days. In addition, the effects of DEX on PDL cells in non-mineralizing media were determined. Cells were stained weekly to evaluate mineral-like nodules, using the Von Kossa method. Northern blot analyses for mRNA steady state levels for several bone-associated proteins, i.e., osteopontin (OPN), bone sialoprotein (BSP), alkaline phosphatase (ALP), osteocalcin (OCN), alpha 2(1)(type 1) collagen and osteonectin (ON), were performed. DNA levels were also determined during the 30-day mineralization period. Under phase contrast microscopy, PDL cells in non-mineralizing media treated with DEX exhibited a more spindle-shaped morphology when compared with similar cells not exposed to DEX. Mineralizing conditions were required to induce mineral nodule formation. However, in this situation, mineral induction was independent of DEX; and furthermore, DEX-treated cells did not exhibit a different morphological pattern when compared with non-DEX treated cells. Mineral-like nodules were first seen at day 15, in concert with an increase followed by a decrease in expression of type I collagen and ON mRNA in both DEX-treated and non-treated cultures. Using Northern blot analysis for detection of specific proteins, we found that PDL cells did not express OPN, BSP, OCN, or ALP under any of the conditions used in this study. DEX did not alter DNA content in the cultures during the mineralization period. These results confirm that human periodontal ligament cells can be induced to mineralize in vitro and indicate that dexamethasone does not significantly alter the extent and pattern of mineralization.
...
PMID:Expression of extracellular matrix proteins in human periodontal ligament cells during mineralization in vitro. 915 36

Our aim was to study the role of various extracellular matrices (ECM) on growth and differentiation of marrow stromal cells in vitro. Morphology changes, gene expression, and enzymatic activities were monitored in stromal osteoblastic MBA-15 and adipocytic 14F1.1 cells. These stromal cells were plated on dishes precoated with different substrata, such as matrigel (basement membrane), collagen type I, and endothelial ECM, and compared with cells plated on protein-free dishes. Striking morphological differences were observed when the cells grew on these different substrata. Changes in cell shape and growth also led to differential mRNA expression and enzymatic activities. When MBA-15 cells were plated on collagen, there was a decrease in mRNA for alkaline phosphatase (ALK-P), osteopontin (OP), and osteonectin (ON), and an increase in mRNA for procollagen (I). A differential effect was noted on 14F1.1 cells, the mRNA for ALK-P increased, the expressions of OP and ON lowered, and no expression for procollagen (I) was monitored. MBA-15 cells cultured on matrigel had decreased mRNA for ALK-P and OP, while they had increased ON mRNA expression and remained unchanged for procollagen I. No change in mRNA expression by 14F1.1 cells was monitored when cultured on matrigel. Functional enzymatic activities of ALK-P markedly decreased in MBA-15 cells cultured on various substrata, and increased or were unchanged in 14F1.1 cells. An additional enzyme, neutral endopeptidase (CD10/NEP), altered differentially in both cell types; this enzymatic activity increased or was unchanged when cells were cultured on these matrices. The results indicate a specific role for different ECM on various stromal cell types and their function.
...
PMID:Phenotypic expression of marrow cells when grown on various substrata. 917 88

The plasma concentrations of two bone matrix proteins (osteocalcin, osteonectin) were monitored in 56 samples from 14 patients receiving renal transplants and the values compared with serum bone alkaline phosphatase mass concentrations and osteotropic hormone levels (parathyroid hormone, calcitriol). There were no significant changes in the concentrations of plasma osteonectin at any time after transplantation, as compared with the values before transplantation (P > 0.1). None of the plasma samples showed osteonectin levels above the reference interval. There was a weak but significant relationship between platelet counts and plasma osteonectin levels (r = +0.322; P < 0.05). Osteocalcin showed a marked decrease of the values 1 week following transplantation as compared with the values before transplantation without further change of the values 1 and 3 months after transplantation (P > 0.5) whereas 3 months after transplantation bone alkaline phosphatase levels were higher than before transplantation (P < 0.05). Multiple regression analysis (performed with data from 42 samples obtained after transplantation) revealed serum creatinine as an independent predictor of plasma osteocalcin whereas serum calcitriol was an independent predictor of serum bone alkaline phosphatase (P < 0.05). No correlation was observed between serum calcitriol/plasma parathyroid hormone on the one hand and plasma osteocalcin on the other (P > 0.05). After transplantation there was a lack of correlation between serum bone alkaline phosphatase mass concentrations and plasma osteocalcin values (P > 0.05). In conclusion, serum bone alkaline phosphatase should be preferred to bone matrix proteins for the assessment of bone metabolism in patients receiving renal transplants: (a) bone alkaline phosphatase-but not osteocalcin-is significantly correlated with calcitriol and adequately reflects increased bone formation after renal transplantation; (b) interpretation of osteocalcin values is severely hampered by their strong correlation with serum creatinine concentrations; (c) plasma osteonectin determinations are not useful for monitoring bone formation.
...
PMID:Serum bone alkaline phosphatase is superior to plasma levels of bone matrix proteins for assessment of bone metabolism in patients receiving renal transplants. 920 30


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---