Phenobarbital (PB) is a non-genotoxic liver tumor promoter used extensively in initiation-promotion protocols. To determine the mode of PB action, double transgenic mice overexpressing both the c-myc and transforming growth factor (TGF)-alpha genes were treated with PB in the food for 10 weeks, from 3 weeks of age. After 3-4 weeks on PB a peak in liver mass was noted, which subsequently leveled...

Concentrations of As, Cd, Cu, Fe, Hg, Pb and Zn were evaluated in surface sediments of two estuaries from Puerto Rico, known as San José Lagoon (SJL) and Joyuda Lagoon. Significantly higher concentrations in microg/g dw of Cd (1.8 vs. 0.1), Cu (105 vs. 22), Hg (1.9 vs. 0.17), Pb (219 vs. 8), and Zn (531 vs. 52) were found in sediment samples from SJL when compared to Joyuda Lagoon. Average conc...

The four cupferronate ions in the dinuclear title compound, [Pb(2)(C(6)H(5)N(2)O(2))(4)], O,O'-chelate to the two Pb(II) atoms; two of the four nitroso O atoms are also involved in bridging. The geometry of both five-coordinate Pb(II)atoms is distorted Ψ-octa-hedral; if another two longer inter-molecular Pb⋯O inter-actions [at 2.955 (1) and 3.099 (1) Å] are considered, the geometry is a distort...

The chemokine stromal cell-derived factor-1 (SDF-1), and its receptor, CXCR-4, have been implicated in the homing and mobilization of human CD34(+) cells. We show here that SDF-1 may also be involved in hematopoiesis, promoting the proliferation of human CD34(+) cells purified from normal adult peripheral blood (PB). CXCR-4 was expressed on PB CD34(+) cells. The amount of CXCR-4 on PB CD34(+) c...

Phenobarbital (PB) treatment impairs the biliary excretion of some organic anions. One mechanism may involve direct competition for biliary excretion by PB and/or a PB metabolite. Alternatively, PB may alter the expression and/or function of hepatic organic anion transport proteins. The role of multidrug resistance-associated protein 2 (Mrp2) in the biliary excretion of PB and metabolites was s...

Phytoremediation is an effective method to remediate Pb-contaminated soils and root exudates play an important role in this process. Based on gas chromatography-mass spectrometry (GC-MS) and metabolomics method, this study focuses on the comparative metabolic profiling analysis of root exudates from the Pb-accumulating and non-accumulating ecotypes of Sedum alfredii treated with 0 and 50 μmol/L...

The superconducting transition temperature (T(C)) in nanostructured Pb decreases from 7.24 to 6.4 K as the particle size is reduced from 65 to 7 nm, below which superconductivity is lost rather abruptly. In contrast, there is a large enhancement in the upper critical field (H(C2)) in the same size regime. We explore the origin of the unusual robustness of T(C) over such a large particle size ra...

Recent studies suggest that the developmental toxicity associated with childhood lead poisoning may be attributable to interactions of Pb(II) with proteins containing thiol-rich structural zinc-binding sites. Here, we report detailed structural studies of Pb(II) in such sites, providing critical insights into the mechanism by which lead alters the activity of these proteins. X-ray absorption sp...

Results of in situ atomic force microscopy (AFM), ex situ AFM, optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction were combined with previous macroscopic investigations to characterize aqueous Pb(NO3)2 reaction with hydroxylapatite (Ca5(PO4)3OH) (HAP). Experiments were conducted by immersing particulate HAP crystals in the AFM fluid cell in s...

The Pb(II) atom in the polymeric title compound, {[Pb(C(13)H(11)N(4)O)(CH(3)OH)(2)]ClO(4)}(n), is coordinated by an N'-[1-(pyridin-2-yl-κN)ethyl-idene]isonicotinohydrazidate ligand via O,N,N'-donors and simultaneously bridged by a neighbouring ligand via the isonicotinoyl N atom; two additional sites are occupied by methanol O atoms. The resultant supra-molecular chain is a zigzag along the c a...