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.

The determination of serum acid and alkaline phosphatase activity with 4 - aminoantipyrine (A.A.P.).

Abstract: C6H5 Gottlieb and Marsh (1946), using alka:ine ferricyanide as the oxidant, devised a method for the estimation of certain phenolic fungicides with A.A.P. The procedure was modified by Grifols (1951) for the determination of phenol in the measurement of alkaline phosphatase activity in body fluids. This author made a careful study of the factors which control the development of the colour and his results showed good correlation with those obtained by the method of King (1951). Advantages claimed for the method were that the reagent did not react with proteins, thus obviating their precipitation during the estimation, and also the colour development was comparatively rapid. The use of A.A.P. as a reagent for phenol appeared to be of potential value especially if its use could be extended to the estimation of serum acid phosphatase activity. Considerable modification of the original Grifols procedure was found to be necessary in order to measure both alkaline and acid phosphatase activity in blood. The use of calibration curves, the stability of the colour, and the effect of the presence of serum

Mechanical stimulation of osteopontin mRNA expression and synthesis in bone cell cultures.

Abstract: We have shown earlier that mechanical stimulation by intermittent hydrostatic compression (IHC) promotes alkaline phosphatase and procollagen type I gene expression in calvarial bone cells. The bone matrix glycoprotein osteopontin (OPN) is considered to be important in bone matrix metabolism and cell-matrix interactions, but its role is unknown. Here we examined the effects of IHC (13 kPa) on OPN mRNA expression and synthesis in primary calvarial cell cultures and the osteoblast-like cell line MC3T3-E1. OPN mRNA expression declined during control culture of primary calvarial cells, but not MC3T3-E1 cells. IHC upregulated OPN mRNA expression in late released osteoblastic cell cultures, but not in early released osteoprogenitor-like cells. Also, in both proliferating and differentiating MC3T3-E1 cells, OPN mRNA expression and synthesis were enhanced by IHC, differentiating cells being more responsive than proliferating cells. These results suggest a role for OPN in the reaction of bone cells to mechanical stimuli. The severe loss of OPN expression in primary bone cells cultured without mechanical stimulation suggests that disuse conditions down-regulate the differentiated osteoblastic phenotype.

The Effects Of Particulate Cobalt, Chromium And Cobalt-chromium Alloy On Human Osteoblast-like Cells In Vitro

Abstract: Particulate wear debris can induce the release of bone-resorbing cytokines from cultured macrophages and fibroblasts in vitro, and these mediators are believed to be the cause of the periprosthetic bone resorption which leads to aseptic loosening in vivo. Much less is known about the effects of particulate debris on the growth and metabolism of osteoblastic cells. We exposed two human osteoblast-like cell lines (SaOS-2 and MG-63) to particulate cobalt, chromium and cobalt-chromium alloy at concentrations of 0, 0.01, 0.1 and 1.0 mg/ml. Cobalt was toxic to both cell lines and inhibited the production of type-I collagen, osteocalcin and alkaline phosphatase. Chromium and cobalt-chromium were well tolerated by both cell lines, producing no cytotoxicity and no inhibition of type-I collagen synthesis. At the highest concentration tested (1.0 mg/ml), however, chromium inhibited alkaline phosphatase activity, and both chromium and cobalt-chromium alloy inhibited osteocalcin expression. Our results clearly show that particulate metal debris can modulate the growth and metabolism of osteoblastic cells in vitro. Reduced osteoblastic activity at the bone-implant interface may be an important mechanism by which particulate wear debris influences the pathogenesis of aseptic loosening in vivo.

Rat calvarial cell lines immortalized with SV-40 large T antigen: constitutive and retinoic acid-inducible expression of osteoblastic features.

Abstract: Two new bone cell lines were established by immortalizing cells derived from embryonic rat calvariae with a recombinant retrovirus containing the cDNA for SV-40 large T antigen and the neomycin resistance gene. One cell line, RCT- 1, isolated from early digest cells, a population which typically does not express osteoblastic features, displayed osteoblastic characteristics only after 3 days of treatment with 1 μM retinoic acid: alkaline phosphatase activity increased from 0.003 to 0.25 μmol/min · mg protein, the steady state level of type I procollagen mRNA increased 4-fold, and the cells acquired a PTH-stimulatable adenylate cyclase (EC60,10 nM). mRNA for osteopontin, an abundant bone matrix protein, was induced in RCT-1 cells by 1,25-dihydroxyvitamin D3 (10 nM). The second cell line, RCT-3, isolated from late digest cells, a population previously shown to be enriched with differentiated osteoblasts, expressed constitutively the properties described above. In addition, RCT-3 cells responded to interleuki...