Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q9UMR3 (NMR)
 150,598 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have determined the dose-response of 1,25-dihydroxyvitamin D-3 (1,25-(OH)2D3) on the intracellular free calcium-ion concentration ([Ca2+]i) in the osteoblastic osteosarcoma cells, ROS 17/2.8, using 19F-NMR and the intracellular divalent cation indicator, 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5F-BAPTA). The dose-response demonstrated an inverted U-shaped relationship with maximal elevation of [Ca2+]i at doses of 1 to 10 nM 1,25-(OH)2D3. At 10 nM, 1,25-(OH)2D3 elevated the [Ca2+]i from a control level of 118 +/- 4 nM to a peak value of 237 +/- 8 nM within 40 min. 1,25-(OH)2D3 also increased the initial rate of Ca2+ influx into ROS 17/2.8 cells, measured by 45Ca uptake, with a dose-response relationship which paralleled its effect on [Ca2+]i. Treatment of ROS 17/2.8 cells with Pb2+ at 1 and 5 microM significantly increased [Ca2+]i but significantly reduced the 1,25-(OH)2D3-induced elevation of [Ca2+]i. Simultaneous treatment of naive cells with 1,25-(OH)2D3 and Pb2+ produce little reduction of 1,25-(OH)2D3-induced 45Ca uptake while 40 min treatment with Pb2+ before addition of 1,25-(OH)2D3 significantly reduced the 1,25-(OH)2D3-induced increase in 45Ca influx. These findings suggest that Pb2+ acts by inhibiting 1,25-(OH)2D3-activation of Ca2+ channels and interferes with 1,25-(OH)2D3 regulation of Ca2+ metabolism in osteoblastic bone cells.
 ...
PMID:Lead inhibits 1,25-dihydroxyvitamin D-3 regulation of calcium metabolism in osteoblastic osteosarcoma cells (ROS 17/2.8). 146 69

Lead (Pb) has been shown to perturb cellular calcium (Ca) homeostasis, altering sizes and flux rates of cellular pools of exchangeable Ca and impairing Ca-mediated cell processes. To date, however, a direct effect of Pb on intracellular-free Ca2+ has not yet been demonstrated. Heavy metals bind to the commonly used fluorescent Ca ion indicators with greater affinity than does Ca and thereby interfere with the expected Ca-dependent fluorescence. In this study, the fluorinated Ca ion indicator, 1,2-bis(2-amino-5-fluorophenoxy)ethane N,N,N',N'-tetraacetic acid (5F-BAPTA), and 19F NMR were used to measure the free intracellular Ca ion concentration ([Ca2+]i) in the rat osteoblastic bone cell line, ROS 17/2.8. Both Pb and Ca bind to 5F-BAPTA with high affinity, but the Pb-5F-BAPTA comple produces a 19F NMR signal at a chemical shift distinct from 5F-BAPTA and the Ca-5F-BAPTA complex. The apparent dissociation constants for Pb-5F-BAPTA and Ca-5F-BAPTA are 2 X 10(-10) M and 5 X 10(-7) M, respectively, at 30 degrees C, pH 7.1, and Mg2+ (0.5 mM). Thus, this methodology allows for the simultaneous identification and quantification of free Pb and free Ca ion concentrations. Determinations of [Ca2+]i were based on 19F NMR measurements of 5F-BAPTA-loaded ROS 17/2.8 osteoblastic bone cells that were attached to collagen-coated microcarrier beads. Cells were continuously superfused with freshly oxygenated medium at 30 degrees C. Under these conditions, the [Ca2+]i of ROS 17/2.8 cells was observed to be 128 +/- 14 nM.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Development of 19F NMR for measurement of [Ca2+]i and [Pb2+]i in cultured osteoblastic bone cells. 211 59

Using 19F-NMR and the intracellular divalent cation indicator, 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid, we have recently demonstrated that Pb2+ treatment elevates the intracellular free calcium ion concentration ([Ca2+]i) of rat osteoblastic osteosarcoma cells (ROS 17/2.8) (Proc. Natl. Acad. Sci. USA (1989) 86, 5133-5135). In this study, we have examined the effects of Pb2+ on the basal and parathyroid hormone (PTH)-stimulated levels of [Ca2+]i and cAMP in cultured ROS 17/2.8 cells. PTH treatment (400 ng/ml) stimulated a 150% elevation in [Ca2+]i from a control level of 105 +/- 25 nM to a concentration of 260 +/- 24 nM. Treatment of ROS 17/2.8 cells with Pb2+ (5 microM) alone produced a 50% elevation in the [Ca2+]i to 155 +/- 23 nM. Pb2+ treatment diminished subsequent elevation in [Ca2+]i in response to PTH administration thereby limiting the peak increase in [Ca2+]i to only 25% or 193 +/- 22 nM. In contrast to the dampening effect of Pb2+ on the peak rise in [Ca2+]i produced by PTH, Pb2+ (1 to 25 microM) had no effect on PTH-induced increments in intracellular cAMP levels. Hence, Pb2+ dissociated the PTH stimulation of adenylate cyclase from PTH effects on [Ca2+]i and shifted the regulation of [Ca2+]i beyond the control of PTH modulation. These observations further extend the hypothesis that an early toxic effect of Pb2+ at the cellular level is perturbation of [Ca2+]i homeostasis.
 ...
PMID:Effect of lead on parathyroid hormone-induced responses in rat osteoblastic osteosarcoma cells (ROS 17/2.8) using 19F-NMR. 216 14

Lead (Pb) has been shown to perturb Ca-mediated cellular processes. However, to date, a direct effect of Pb on intracellular free Ca2+ concentration ([Ca2+]i) has not been demonstrated. 19F NMR in combination with 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5F-BAPTA) was used to simultaneously measure [Ca2+]i and intracellular free Pb2+ concentration ([Pb2+]i) in the rat osteoblastic bone cell line ROS 17/2.8. The basal concentration of [Ca2+]i in ROS 17/2.8 cells was measured to be 128 +/- 24 nM. Treatment with Pb2+ at 5 and 25 microM produced sustained 50% and 120% increases in [Ca2+]i, respectively, over a time course of 5 hr. At a medium Pb2+ concentration of 25 microM, the entry of Pb2+ into ROS 17/2.8 cells yielded measurable [Pb2+]i in cultured cells. Collectively, these findings advance the hypothesis that Pb toxicity is mediated, in part, through perturbations in [Ca2+]i.
 ...
PMID:Lead increases free Ca2+ concentration in cultured osteoblastic bone cells: simultaneous detection of intracellular free Pb2+ by 19F NMR. 250 Jun 64

Lead characteristically perturbs processes linked to the calcium messenger system. This study was undertaken to determine the role of PKC in the Pb2+ induced rise of [Ca2+]i. [Ca2+]i was measured using the divalent cation indicator, 1,2-bis(2-amino-5-fluorophenoxy) ethane N, N,N',N'-tetraacetic acid (5F-BAPTA) and 19F-NMR in the osteoblast cell line, ROS 17/2.8. Treatment of cells with Pb2+ at 1 and 5 microM produced a rise in [Ca2+]i from a basal level of 125 nM to 170 nM and 230 nM, respectively, while treatment with phorbol 12-myristate 13-acetate (PMA) (10 microM), an activator of PKC, produced a rise in [Ca2+]i to 210 nM. Pretreatment with calphostin C, a potent and highly selective inhibitor of PKC activation failed to produce a change in basal [Ca2+]i and prevented any rise in [Ca2+]i in response to Pb2+. To determine whether Pb2+ acts directly on PKC, we measured the Pb2(+)-dependent activation of phosphatidylserine/diolein-dependent incorporation of 32P from ATP into histone and endogenous TCA precipitable proteins in the 100,000 X g supernatant from homogenized ROS 17/2.8 cells. The free concentrations of Pb2+ and Ca2+ were set using 5F-BAPTA; and [Ca2+] and [Pb2+] in the PKC reaction mixtures were confirmed by 19F-NMR. We found that Pb2+ activates PKC in the range of 10(-11)-10(-7) M, with an activation constant of 1.1 X 10(-10) M, whereas Ca2+ activates PKC in the range from 10(-8) to 10(-3) M, with an activation constant of 3.6 X 10(-7) M. These data suggest that Pb2+ activates PKC in ROS 17/2.8 cells and that Pb2+ activation of PKC mediates the documented rise in [Ca2+]i and, perhaps, other toxic effects of Pb2+.
 ...
PMID:Lead induced rise in intracellular free calcium is mediated through activation of protein kinase C in osteoblastic bone cells. 919 67

Nephrotoxicity is one of the major dose limiting side effects of cisplatin chemotherapy. The antitumor and toxic effects are mediated in part by different mechanisms, thus, permitting a selective inhibition of certain side effects. The influence of O-(3-piperidino-2-hydroxy-1-propyl)nicotinic amidoxime (BGP-15) - a poly(ADP-ribose) polymerase (PARP) inhibitor - on the nephrotoxicity and antitumor efficacy of cisplatin has been evaluated in experimental models. BGP-15 either blocked or significantly reduced (60-90% in 100-200 mg/kg oral dose) cisplatin induced increase in serum urea and creatinine level in mice and rats and prevented the structural degeneration of the kidney, as well. The nephroprotective effect of BGP-15 treatment was revealed also in living mice by MRI analysis manifesting in the lack of oedema which otherwise developed as a result of cisplatin treatment. The protective effect was accompanied by inhibition of cisplatin-induced poly-ADP-ribosylation and by the restoration of the disturbed energy metabolism. The preservation of ATP level in the kidney was demonstrated in vivo by localized NMR spectroscopy. BGP-15 decreased cisplatin-induced ROS production in rat kidney mitochondria and improved the antioxidant status of the kidney in mice with cisplatin-induced nephropathy. In rat kidney, cisplatin caused a decrease in the level of Bcl-x, a mitochondrial protective protein, and this was normalized by BGP-15 treatment. On the other hand, BGP-15 did not inhibit the antitumor efficacy of cisplatin in cell culture and in transplantable solid tumors of mice. Treatment with BGP-15 increased the mean survival time of cisplatin-treated P-388 leukemia bearing mice from 13 to 19 days. PARP inhibitors have been demonstrated to diminish the consequences of free radical-induced damage, and this is related to the chemoprotective effect of BGP-15, a novel PARP inhibitor. Based on these results, we propose that BGP-15 represents a novel, non-thiol chemoprotective agent.
 ...
PMID:BGP-15 - a novel poly(ADP-ribose) polymerase inhibitor - protects against nephrotoxicity of cisplatin without compromising its antitumor activity. 1193 42

The proliferative effects of thirty Oriental medicinal herbs on MCF-7 (estrogen-sensitive breast cancer cell line) and ROS 17/2.8 osteoblast-like cells were determined using the MTT assay. Methanol extracts from several herbs was found to show proliferative activity on the above two cell lines in the range of 5 to 100 microg/mL. Among these active herbs, the methanol extract from the rhizomes of Drynaria fortunei showed the most potent proliferative activity, and the cell proliferations were significantly increase by 136 and 158% in the MCF-7 and ROS 17/2.8 cells, respectively, when treated with 100 microg/mL. Through a bioassay-guided separation, eight flavonoids, including four new flavan-3-ols and two propelargonidins, together with the known (-)-epiafzelechin and naringin, were isolated. Their chemical structures were characterized as (-)-epiafzelechin (1), (-)-epiafzelechin-3-O-beta-D-allopyranoside (2), (-)-epiafzelechin-3-O-(6"-O-acetyl)-beta-D-allopyranoside (3), 4beta-carboxymethyl-(-)-epiafzelechin methyl ester (4), 4beta-carboxymethyl-(-)-epiafzelechin sodium salt (5), naringin (6), (-)-epiafzelechin-(4beta-->8)-4beta-carboxymethylepiafzelechin methyl ester (7) and (-)epiafzelechin-(4beta-->8, 2beta-->O-->7)-epiafzelechin-(4beta-->8)-epiafzelechin (8) by extensive 1D and 2D NMR spectroscopy. Most of these flavonoids, in the range of 10(-15) to approximately 10(-6) M, accelerated the proliferation of MCF-7 cell, with compounds 7 and 8, in the range of 10(-15) to approximately 10(-12) M, showing especially potent proliferation effects. Meanwhile, seven flavonoids, with the exception of compound 4, stimulated the proliferation of ROS 17/2.8 cells in the range of 10(-15) to approximately 10(-6) M, with compounds 5-8 especially accelerating the proliferation, in dose-dependent manners (10(-15) to approximately 10(-9) M), and their proliferative effect was much stronger than that of E2 and genistein. These results suggest that propelargonidin dimers and trimers isolated from the rhizomes of Drynaria fortunei may be useful as potential phytoestrogens, which play important physiological roles in the prevention of postmenopausal osteoporosis.
 ...
PMID:Proliferative effects of flavan-3-ols and propelargonidins from rhizomes of Drynaria fortunei on MCF-7 and osteoblastic cells. 1296 97

2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) is commonly used to detect the generation of reactive oxygen intermediates and for assessing the overall oxidative stress in toxicological phenomenon. It has been suggested that DCFH-DA crosses the cell membrane, subsequently undergoing deacetylation by intracellular esterases. The resulting 2',7'-dichlorodihydrofluorescein (DCFH) is proposed to react with intracellular hydrogen peroxide or other oxidizing ROS to give the fluorescent 2',7'-dichlorofluorescein (DCF). Using an NMR chemical shift-polarity correlation, we have determined that DCFH-DA and DCFH are located well within the lipid bilayer and certainly not at the interface. These results, therefore, put into serious question the proposed ability of DCFH to come in contact with the aqueous phase and thereby interact with aqueous intracellular ROS and components. However, H2O2 and superoxide can cross or at least penetrate the lipid bilayer and react with certain lipophilic substrates. This may well describe the mode of reaction of these and other ROS with DCFH.
 ...
PMID:Active oxygen chemistry within the liposomal bilayer. Part IV: Locating 2',7'-dichlorofluorescein (DCF), 2',7'-dichlorodihydrofluorescein (DCFH) and 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) in the lipid bilayer. 1521 Mar 70

Since our original demonstration of the metabolism of 1alpha,25(OH)2D3 into 1alpha,25(OH)2-3-epi-D3 in human keratinocytes, there have been several reports indicating that epimerization of the 3 hydroxyl group of vitamin D compounds is a common metabolic process. Recent studies reported the metabolism of 25OHD3 and 24(R),25(OH)2D3 into their respective C-3 epimers, indicating that the presence of 1alpha hydroxyl group is not necessary for the 3-epimerization of vitamin D compounds. To determine whether the presence of a 25 hydroxyl group is required for 3-epimerization of vitamin D compounds, we investigated the metabolism of 1alphaOHD3, a non-25 hydroxylated vitamin D compound, in rat osteosarcoma cells (ROS 17/2.8). We noted metabolism of 1alphaOHD3 into a less polar metabolite which was unequivocally identified as 1alphaOH-3-epi-D3 using the techniques of HPLC, GC/MS, and 1H-NMR analysis. We also identified 1alphaOH-3-epi-D3 as a circulating metabolite in rats treated with pharmacological concentrations of 1alphaOHD3. Thus, these results indicated that the presence of a 25 hydroxyl group is not required for 3-epimerization of vitamin D compounds. Furthermore, the results from the same studies also provided evidence to indicate that 1alphaOH-3-epi-D3, like 1alphaOHD3, is hydroxylated at C-25. We then evaluated the biological activities of 1alphaOH-3-epi-D3. Treatment of normal rats every other day for 7 days with 2.5 nmol/kg of 1alphaOH-3-epi-D3 did not raise serum calcium, while the same dose of 1alphaOHD3 increased serum calcium by 3.39 +/- 0.52 mg/dl. Interestingly, in the same rats which received 1alphaOH-3-epi-D3 we also noted a reduction in circulating PTH levels by 65 +/- 7%. This ability of 1alphaOH-3-epi-D3 to suppress PTH levels in normal rats without altering serum calcium was further tested in rats with reduced renal function. The results indicated that the ED50 of 1alphaOH-3-epi-D3 for suppression of PTH was only slightly higher than that of 1alpha,25(OH)2D3, but that the threshold dose of the development of hypercalcemia (total serum Ca > 10.5 mg/dl) was nearly 80 times higher. These findings indicate that 1alphaOH-3-epi-D3 is a highly selective vitamin D analog with tremendous potential for treatment of secondary hyperparathyroidism in chronic renal failure patients.
 ...
PMID:Isolation and identification of 1alpha-hydroxy-3-epi-vitamin D3, a potent suppressor of parathyroid hormone secretion. 1608 54

Six new phenylethanoid glucosides, ternstrosides A-F (1-6), a new kaempferol derivative (7), and eight known compounds were isolated from the fresh leaves of Ternstroemia japonica. The structures were elucidated by 1D and 2D NMR spectroscopic analyses. Compounds 1-7 showed potent antioxidative activity in three different tests, with IC50 values in the range 3.26-6.50 microM in the hydroxyl radical (*OH) inhibitory activity test, 33.29-82.21 microM in the total ROS (reactive oxygen species) inhibitory activity test, and 1.14-13.53 microM in the peroxynitrite (ONOO-) scavenging activity test.
 ...
PMID:Antioxidative phenolics from the fresh leaves of Ternstroemia japonica. 1706 50


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