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Results for “Uranium Compounds”

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At least 271 records · Page 15Linked to original sources
PubMed2002

[Malignant transformation of human bronchial epithelial cell (BEAS-2B) induced by depleted uranium].

BACKGROUND & OBJECTIVE: It is clear from works already reported that depleted uranium (DU) affect human health. However, the late effect, especially the carcinogenesis, was not clearly understood. This study was designed to investigate the malignant transformation of human bronchial epithelial cell induced by insoluble DU and lung cancer related gene expression pattern, through imitating the condition that human absorbs depleted uranium aerosol. METHODS: Adenovirus-12/SV40 virus immortalized human bronchial epithelial cells (BEAS-2B) were reacted with insoluble DU oxide (dUO2); the characteristics of malignant transformation of cells were identified through observing the multiplication time of different generation cells, serum resistance, colony formation rate of semi-solid agar, and tumorigenesis in nude mice. Gene expression pattern of transferred BEAS-2B cell induced by DU was determined using 213 lung cancer related gene arrays. RESULTS: The multiplication time of BEAS-2B cell treated with DU was obviously decreased and the serum reistance was significantly increased in 5th generation; the anchorage independent growth (semi-solid agar colony formation) was appeared in 10th generation cell. The 15th generation cell formed tumor in nude mice. DMSO showed overt protection effect on malignant transformation of BEAS-2B cell. The analyzing results of 213 lung cancer related gene arrays showed that the expression level changed in more than 70 genes of transferred cells, including the overt decrease of level of gene expression in more than 10 genes. CONCLUSION: DU has carcinogenesis in vitro.

Animals↗
PubMed2003

[In vitro uranyle affinity of per (3,6-anhydro-2-O-carboxyméthyle)-alpha-cyclodextrin and conditions required for in vivo application].

Per (3.6-anhydro-2-O-carboxymethyle)- alpha-cyclodextrin ([1]) is a polydentate analog of EDTA, a well-known cation chelating reagent. [1] exhibits strong affinities in vitro for lanthanids, cobalt and also for uranyl cations. Hence, a 1:1 stoechiometry and a high affinity for uranyle (6<logK<7) is found in vitro. Moreover, [1] is not hemolytic and exhibits not lettral properties in mice (LD(50)=42mM). In vivo injection at supralethal amounts of uranyl complex of [1] prevents immediate death in mice while unable to protect against later death. Pharmacocinetic studies show that a dissociation of the complex occurs lead to the release of free uranyle. Other complexation assays using [1] grafted tissues show that chelating properties for lead and uranyle differ from thoses observed in vitro.

Animals↗
PubMed2003

On the complex formation equilibria between dioxouranium(VI) and sulfate ions.

The complexation equilibria between UO2(2+) and SO4(2-) ions have been studied at 25 degrees C in the ionic medium 3 M NaClO4 by potentiometry, by spectrophotometry and by solubility measurements of UO2(IO3)2. The potentiometric investigation was carried out with the Hg-Hg2SO4(s)-SO4(2-) half-cell and glass electrode in the sulfate concentration range 0.005 to 0.07 M. The optical absorbances in the UV-visible region and the solubility data cover the ligand concentration range 0.005 to 0.3 M. The data could be explained by assuming the complexes and equilibrium constants [Table: see text]. The constants in the infinite dilution reference state, log beta1o = 3.08 +/- 0.15 and log beta2o = 4.28 +/- 0.15, estimated by assuming the validity of the specific interaction theory, are practically coincident with literature data.

Numerical Analysis, Computer-Assisted↗
PubMed2003

On the hydrolysis of the dioxouranium(VI) ion in sulfate solutions.

The formation of ternary UO2(2+)-(OH-)-SO4(2-) complexes has been studied at 25 degrees C in 3 M NaClO4 ionic medium by measurements with a glass electrode. The solutions had uranium concentrations between 0.3 and 30 mM, sulfate between 20 and 200 mM, and 1.66 < or = [SO4(2-)]/[U(VI)] < or = 300. The hydrogen ion concentration ranged from 10(-3) M to incipient precipitation of basic sulfates. This occurred, depending on the metal concentration, at [H+] between 10(-4) and 10(-5.3) M. In the interpretation of the data the stabilities of binary complexes were assumed from independent sources. The data could be explained with the mixed complexes and equilibria (beta(pqr)(3sigma) refers to pUO2(2+) + qH2O + rSO4(2-) <==> (UO2)p(OH)q(SO4)r(2p-q-2r) + qH+): logbeta222 = -2.94 +/- 0.03, logbeta341 = -9.82 +/- 0.06, logbeta211 = -0.30 +/- 0.09, logbeta212 = 1.09 +/- 0.09, logbeta351 = -15.04 +/- 0.09 and logbeta462 = -14.40 +/- 0.06. The fit could be improved by including UO2OH+ with logbeta110 = -5.1 +/- 0.1. The identity of the minor species remains, however, an open question.

Hydrolysis↗
PubMed2002

[Synthesis and spectral characterization of U(VI) and Th(IV) complexes of thenoylpyrazolone-ethylenediamine].

Two novel bis-schiff base complexes [UO2 (PMTHP)2en] and [Th(PMTHP)2en(NO3)2] have been synthesized, where (PMTHP)2en = N,N'-bis[(1-phenyl-3-methyl-5-oxo-5-pyrazolinyl)- 2-thenoylmethylidyne] ethylenediamine, and characterized by elemental analysis, IR, UV-Vis, 1H NMR, 13C NMR and molar conductance measurements. The results show that the bis-schiff base is a quadridentate ligand and the nitrate a bidentate ligand, and the uranyl and thorium ions exhibit coordination of six and eight in the complexes, respectively.

Chelating Agents↗
PubMedDate not supplied

[Changes in cellular radiosensitivity by modifying the cytoplasmic membranes].

The radiosensitivity of mouse myeloma and E. coli cells in the presence of Mg2+ and UO2(2+) ions has been investigated. It has been shown that Mg2+ ions (10(-4) M) do not influence the viability of E. coli and mouse myeloma cells. The presence of Mg2+ ions during irradiation reduces the survival rate of E. coli cells, but the addition of Mg2+ ions after irradiation does not influence the radiosensitivity of E. coli cells. Comparison of the results on the influence of Mg2+ ions upon cells and bilayer lipid membranes (BLM) permits us to suppose that Mg2+ ions increase the positive charge of the membranes thus promoting the increase in the number of short-lived radiolysis products which impair membranes and increase cell radiosensitivity. UO2(2+) ions (10(-4) M) increase the radioresistance of E. coli cells which can be associated with the increase in the lateral membrane viscosity, as it was shown in the studies on BLM.

Animals↗
PubMed2003

Dioxouranium-carboxylate complexes. Formation and stability of acetate species at different ionic strengths in NaCl(aq).

The formation and stability of UO2(2+)-acetate complexes was studied potentiometrically, at T = 25 degrees C, at different ionic strength, 0 < I < or = 1 mol dm(-3), in aqueous NaCl solutions. Computer analysis allowed us to find the species UO2(ac)+, UO2(ac)2(0), UO2(ac)3- and UO2(ac)3(OH)2-. The dependence on ionic strength of formation constants was taken into account by using both a simple Debye-Hückel type equation and the SIT (Specific ion Interaction Theory) approach. A critical examination of the present results is given together with a comprehensive analysis of literature data.

Acetates↗