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PubMed2003

Triamidotriazacyclononane complexes of group 3 metals. Synthesis and crystal structures.

Reaction of yttrium and lanthanide trichlorides (Ln = La, Eu, Yb) with 1 equiv of the trisodium salt of 1,4,7-tris(dimethylsilylaniline)-1,4,7-triazacyclononane (Na(3)[(SiMe(2)NPh)(3)-tacn](THF)(2)) gives good yields of the compounds [M[(SiMe(2)NPh)(3)-tacn]] (M = Y (1), Eu (3), Yb (4)) and [La[(SiMe(2)NPh)(3)-tacn](THF)] (2). Reduction of 3 with Na/Hg followed by recrystallization in the presence of diglyme yielded crystals of [Eu[(SiMe(2)NPh)(3)-tacn]][Na(diglyme)(2)] (5). Synthesis of the uranium(III) complex [U[(SiMe(2)NPh)(3)-tacn]] (6) is achieved by reaction of 1 equiv of Na(3)[(SiMe(2)NPh)(3)-tacn](THF)(2) with uranium triiodide. The U(IV) complexes, [U[(SiMe(2)NPh)(3)-tacn]X] (X = Cl (7); I (8)), were prepared via oxidation of 6 with benzyl chloride or I(2), but salt metathesis from UCl(4) provided a higher yield route for 7. The solid-state structures of 1-7 were determined by single-crystal X-ray diffraction. The ligand [(SiMe(2)NPh)(3)-tacn] generates a trigonal prismatic coordination environment for the metal center in the neutral complexes 1, 3, 4, and 6 and the ionic 5. In 2 the six nitrogen atoms of the ligand are in a trigonal prismatic configuration with the oxygen atom of the THF capping one of the triangular faces of the trigonal prism. In 7 the coordination geometry around the uranium atom is best described as bicapped trigonal bipyramidal.

Journal Article↗
PubMedDate not supplied

[Strategy and tactics of radiation protection of the personnel in light of future work on stabilization and reorganization of the "Shelter" compound into radiologically safe system].

The research aim is to analyze the "Shelter" personnel work conditions and to estimate how these conditions specify radiological defense. "Shelter" object remains to be an accumulation of the open radiotoxic materials. It is expected that the usage of standard technologies in such conditions will be connected with the great dose-expense of external and internal irradiation. The significant quantity of the fuel dust (more 30 tonne according to uranium) and the extremely harmful microclimate conditions such as: aggressive radiochemical aerosols, exclusively artificial and obviously insufficient illumination, high humidity, discomfortable temperature regime, high ability of many working places to induce the emotional stress reaction in personnel are the specificity of "Shelter" object. The synergetic influence of radiofactor and "Shelter" object microclimate is very dangerous because of its ability to deteriorate significantly the personnel health up to acute stress reaction. In these cases there appear the episodes of the short disorders of orientation in the surrounding situation, paroxysmal consciousness disturbances which may become the nondirect reason of the overirradiation and growth of work traumatism. That's why the methods of the stress-reaction prophylaxis and improvement of the individual defense become extremely improvement for the "Shelter" object personnel. It was shown that the following medicines are perspective due to their adaptogenic and radioprotective abilities, such as: alpha-2-recombinant interferon, antiinflammatory, steroid, antioxidant and enterosorbtive preparations of biological nature.

Humans↗
PubMed2003

Metabolite profiling in rat urine by liquid chromatography/electrospray ion trap mass spectrometry. Application to the study of heavy metal toxicity.

This work reports the use of reverse-phase liquid chromatography coupled to electrospray ion trap (QIT) mass spectrometry for the analysis of the metabolome in rat urine. An injection of 20 microL of urine into the chromatographic system is followed by a slow gradient elution and mass spectrometric detection in the scanning mode from m/z 100-1000 in both positive and negative modes. Over a time scale of 90 min, 30 and 20 resolved peaks were observed in the positive and the negative modes, respectively, corresponding to the presence of a few hundred m/z ratios. By using a QIT analyzer, data-dependent tandem mass spectrometry of selected m/z ratios identified several compounds in rat urine and characterized various chemical families, including carboxylic acids, amines, sulfated compounds, glucuronides and glycosides, by the observation of characteristic fragment ions or neutral losses. The method has been applied to the investigation of the chronic toxicity of heavy metals in rat urine. A few tens of m/z ratios, differing in intensity more than threefold from control values, were observed in both positive and negative modes. The time variations for some selected ions suggest that LC/ESI-MS could allow selective characterization of biomarkers in response to specific toxic compounds.

Amino Acids↗
PubMed2005

Inclusion of diprotonated [2.2.2]cryptand in the cavity of uranyl-complexed p-phenyltetrahomodioxacalix[4]arene.

In the title compound, 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane dioxo[7,13,21,27-tetraphenyl-3,17-dioxapentacyclo[23.3.1.1(5,9).1(11,15).1(19,23)]ditriaconta-1(29),5,7,9(30),11(31),12,14,19(32),20,22,25,27-dodecaene-29,30,31,32-tetraolato]uranium dimethyl sulfoxide trisolvate, (C(18)H(38)N(2)O(6))[U(C(54)H(40)O(6))O(2)].3C(2)H(6)OS, the uranyl ion is bound to the four phenoxide groups of the deprotonated p-phenyltetrahomodioxacalix[4]arene ligand in a cone conformation, resulting in a dianionic complex. The diprotonated [2.2.2]cryptand counter-ion is located in the cavity defined by the eight aromatic rings of the homooxacalixarene, where it is held by cation-anion, cation-pi and possibly C-H...pi interactions. Dimerization in the packing leads to the formation of sandwich assemblages in which two diprotonated [2.2.2]cryptands are encompassed by two uranyl complexes.

Journal Article↗
PubMed1982

Improvement of the basidiomycete Coprinus sp.

Coprinus sp. C-1 (obtained from uranium mines) was subjected to improvement procedures with the aim of preparing a strain that could degrade cellulose in the straw substrate more rapidly and effectively. The original C-1 strain was highly resistant to UV and X radiation but it was rather sensitive to tris(2-chloroethyl)amine, the effect of which increased when applying simultaneously compounds reacting with mercapto groups of some enzymes. The mutants obtained synthesized during the same interval by up to 94% more N compounds than the original strain the rate of cellulose degradation increasing by about 40%. In certain mutants the content of some essential amino acids simultaneously increased by up to 110%.

Agaricales↗
PubMed2002

Potential late health effects of depleted uranium and tungsten used in armor-piercing munitions: comparison of neoplastic transformation and genotoxicity with the known carcinogen nickel.

Limited data exist to permit an accurate assessment of risks for carcinogenesis and mutagenesis from embedded fragments or inhaled particulates of depleted uranium (DU). Ongoing studies have been designed to provide information about the carcinogenic potential of DU using in vitro and in vivo assessments of morphological transformation as well as cytogenetic, mutagenic, and oncogenic effects. For comparison, we also examined tungsten alloys used in military projectiles and the known carcinogen nickel. Quantitative and qualitative in vitro transformation studies were done to assess the carcinogenic potential of radiation and chemical hazards. Using a human osteosarcoma cell model, we demonstrated that soluble and insoluble DU compounds can transform cells to the tumorigenic phenotype, as characterized by morphological, biochemical, and oncogenic changes consistent with tumor cell behavior. Tungsten alloys and nickel were also shown to be neoplastic transforming agents, although at a frequency less than that of DU. Sister chromatid exchange, micronuclei, and alkaline filter elution assays showed DU and tungsten alloys were genotoxic. Exposure to a nontoxic, nontransforming dose of DU induced a small but statistically significant increase in the number of dicentrics formed in cells. These results suggest that long-term exposure to DU or tungsten alloys could be critical to the development of neoplastic disease in humans and that additional studies are needed.

Carcinogens↗
PubMed2002

Environmental adaptation factors of two yeasts isolated from the leachate of a uranium mineral heap.

Two yeasts from the effluent of a uranium mineral heap were identified as Candida sorbophila and Rhodotorula mucilaginosa. They are well adapted to such an environment as shown by their tolerance to metals and acid pH. However, different mechanisms could be involved in the adaptation: C. sorbophila could be considered to be more acid-tolerant as a function of its specific growth rate and respiratory behavior at acidic pH in an organic medium. However, R. mucilaginosa was capable of growing by 1 log unit when inoculated in a sterilized leaching effluent or in a ferrous mineral medium, without added organic compounds. Indeed, the ability of R. mucilaginosa to grow in a low-nutrient environment could be as important a factor as its acid tolerance for coping in the isolation habitat. In mixed cultures with sulfide-oxidizing bacteria, no effect was observed on the ferrous oxidation normally carried out by these bacteria. However, a negative effect on both yeasts, especially in C. sorbophila, was observed, when the bacteria were present.

Acids↗
PubMed2005

The synthesis, structural, and spectroscopic characterization of uranium(IV) perrhenate complexes.

We report the synthesis, structural, and spectroscopic characterization of a series of uranium(IV)-perrhenato complexes. Three isostructural complexes with general formula [U(ReO4)4(L)4] (where L = tri-n-butylphosphine oxide/TBPO (2), triethyl phosphate/TEP (3), or tri-iso-butyl phosphate/TiBP (4)), have been synthesized, both through the photoreduction of ethanolic {UO2}2+ solutions and also via a novel U(IV) starting material, U(ReO4)4.5H2O (1). Compound 1 has also been used in the preparation of [U(ReO4)4(TPPO)3(CH3CN)].2CH3CN (5) and [U(ReO4)(DPPMO2)3(OH)][ReO4]2.2CH3CN (6), where TPPO represents triphenylphosphine oxide and DPPMO2 represents bis(diphenylphosphino)methane dioxide. All six complexes have been spectroscopically characterized using NMR, UV-vis-NIR, and IR techniques, with 2, 3, 5, and 6 also fully structurally characterized. The U atoms in compounds 2-6 all exhibit eight-coordinate geometry with up to four perrhenate groups in addition to three (DPPMO2 and TPPO) or four (TEP, TiBP, TBPO) coordinated organic ligands. In the case of compounds 5 and 6, the coordination of eight ligands to the U(IV) center is completed by the binding of a solvent molecule (CH3CN) and OH-, respectively. Solid-state physical analysis (elemental and thermogravimetric) and infrared spectroscopy are in agreement with the structural studies. The crystallographic data suggest that the strength of the U(IV)-O-donor ligand bonds decreases across the series R3PO > [ReO4]- > (RO)3PO. Solution-state IR and 31P NMR spectroscopy appear to be in agreement with these solid-state results.

Journal Article↗
PubMed2004

Synthesis and crystal structure of uranium(IV) complexes with compartmental Schiff bases: from mononuclear species to tri- and tetranuclear clusters.

Treatment of U(acac)4 with the hexadentate Schiff base H2L(i) gave the [UL(i)2] complexes 1-4 [H2L1=N,N'-bis(3-methoxysalicylidene)-2-methyl-1,2-propanediamine, H2L2=N,N'-bis(3-methoxysalicylidene)-1,2-phenylenediamine, H2L3=N,N'-bis(3-methoxysalicylidene)-2-aminobenzylamine and H2L4=N,N'-bis(3-methoxysalicylidene)-2,2-dimethyl-1,3-propanediamine for 1-4, respectively]. The [U(L(i))(acac)2] compounds could not be isolated because of their ready disproportionation into [UL(i)2] and U(acac)4. Compounds 2 and 4 adopt a meridional configuration in the solid state and in solution, while exists in solution as the two equilibrating meridional and sandwich isomers and crystallizes in the meridional isomeric form. Reaction of U(acac)4 with H4L5 afforded the expected compound [U(H2L5)(acac)2] (5) [H4L5=N,N'-bis(3-hydroxysalicylidene)-2-methyl-1,2-propanediamine] but, in the presence of H4L6 and H4L7, U(acac)4 was transformed in a serendipitous and reproducible manner into the tri- and tetranuclear U(IV) complexes [U3(L6)(HL6)2(acac)2] (6) and [U4(HL7)4(H2L7)2] (7) [H4L6=N,N'-bis(3-hydroxysalicylidene)-1,2-phenylenediamine and H4L7=N,N'-bis(3-hydroxysalicylidene)-2-aminobenzylamine]. The crystal structures of 6.3thf and 7.5thf show the assembling role of the Schiff-base ligands.

Journal Article↗
PubMed2003

Comparative decorporation efficacy of 3,4,3-LIHOPO, 4,4,4-LIHOPO and DTPA after contamination of rats with soluble forms of 238Pu and 233U.

The aim of this study was to compare the efficacies of DTPA, 3,4,3-LIHOPO and a newly synthesised molecule, 4,4,4-LIHOPO, in removing 233U and 238Pu after internal contamination by soluble forms of those nuclides. For this purpose, intravenous injections of DTPA (30 micromol kg(-1)) or 3,4,3-LIHOPO or 4,4,4-LIHOPO at dosages of 0.3 or 30 micromol kg(-1) were performed 1, 6 and 24 h after contamination of rats by intravenously injected 238Pu citrate and 1 h after intravenous injection of 233U nitrate. Actinide content in the main retention organs and cumulated excretion were measured 48 h after contamination. These experiments show similar decorporation efficacies of 4,4,4-LIHOPO and 3,4,3-LIHOPO for Pu, which are much higher than that of DTPA. At a dosage of 0.3 micromol kg(-1), the two LIHOPO analogues were as efficient as DTPA at a dosage of 30 micromol kg(-1). After U contamination, a 20% decorporation efficacy was obtained for either 3,4,3-LIHOPO or 4,4,4-LIHOPO at a dosage of 30 micromol kg(-1).

Animals↗
PubMed2005

Restraint stress does not enhance the uranium-induced developmental and behavioral effects in the offspring of uranium-exposed male rats.

The influence of stress on postnatal development and behavior was assessed in the offspring of male rats exposed to uranium (U). Eight groups of adult animals received uranyl acetate dihydrate (UAD) in the drinking water at doses of 0, 10, 20 and 40 mg/kg/day during 3 months. One half of rats in each group were concurrently subjected to restraint stress during 2 h per day throughout the study. At the end of the experimental period, male rats were mated with untreated females (1:2). On gestation day 14, one half of pregnant rats were euthanized in order to evaluate maternal toxicity and gestational parameters. The remaining dams were allowed to deliver and wean their offspring. Pups were evaluated for physical development, neuromotor maturation, as well as for behavioral effects. Restraint significantly increased the gravid uterine weight at 40 mg/kg/day. However, no significant interactions between restraint and U could be established in the remaining parameters of maternal toxicity. In the offspring, no remarkable effects of U, restraint or their combination were noted on developmental landmarks, or in the passive avoidance and water maze test. It is concluded that at the current U doses, restraint stress did not enhance the few uranium-induced physical, neuromotor and behavioral changes in the offspring of UAD-exposed male rats.

Animals↗
PubMed2000

Effect of leachability on environmental risk assessment for naturally occurring radioactive materials in petroleum oil fields.

Elevated concentrations of naturally occurring radioactive material (NORM), including 238U, 232Th, and their progeny found in underground geologic deposits, are often encountered during crude oil recovery. Radium, the predominant radionuclide brought to the surface with the crude oil and produced water, co-precipitates with barium in the form of complex compounds of sulfates, carbonates, and silicates found in sludge and scale. These NORM deposits are highly stable and very insoluble under ambient conditions at the earth's surface. However, the co-precipitated radium matrix is not thermodynamically stable at reducing conditions which may enable a fraction of the radium to eventually be released to the environment. Although the fate of radium in uranium mill tailings has been studied extensively, the leachability of radium from crude oil NORM deposits exposed to acid-rain and other aging processes is generally unknown. The leachability of radium from NORM contaminated soil collected at a contaminated oil field in eastern Kentucky was determined using extraction fluids having wide range of pH reflecting different extreme environmental conditions. The average 226Ra concentration in the samples of soil subjected to leachability testing was 32.56 Bq g(-1) +/- 0.34 Bq g(-1). The average leaching potential of 226Ra observed in these NORM contaminated soil samples was 1.3% +/- 0.46% and was independent of the extraction fluid. Risk assessment calculations using the family farm scenario show that the annual dose to a person living and working on this NORM contaminated soil is mainly due to external gamma exposure and radon inhalation. However, waterborne pathways make a non-negligible contribution to the dose for the actual resident families living on farmland with the type of residual NORM contamination due to crude oil recovery operations.

Animal Feed↗
PubMed2006

Degradation of tetraphenylphosphonium bromide at high pH and its effect on radionuclide solubility.

Recently, tetraphenylphosphonium bromide (TPPB) has been used to remove technetium from some radioactive waste streams. However, before TPPB could be approved for use it was necessary to show that TPPB and its degradation products would not have a significant detrimental effect on post-closure performance of a radioactive waste repository. TPPB is known to be stable at neutral pH, however, under alkaline conditions it degrades by an alkaline hydrolysis mechanism to triphenylphosphonium oxide (TPPO). Degradation can also occur by radiolysis to produce triphenylphosphine (TPP). The kinetics of the alkaline hydrolysis degradation of TPPB is described and the solubility of europium, iodine, nickel, technetium(VII) and uranium(VI) in aqueous solutions of TPPB and its degradation products is reported. These results were used to support the use of TPPB in removing technetium from some waste streams.

Hydrolysis↗
PubMed2005

Application of flow field flow fractionation-ICPMS for the study of uranium binding in bacterial cell suspensions.

Field flow fractionation (FFF) is a size-based separation technique applicable to biomolecules, colloids, and bacteria in solution. When interfaced with ICPMS on-line, elemental data can be collected concurrent with size distribution. We employed hyperlayer flow FFF (Fl FFF) methodology to separate cells of Shewanella oneidensis strain MR-1 from exopolymers present in washed cell suspensions. With a channel flow of 4 mL min-1 and a cross-flow of 0.4 mL min-1 cells eluted with a retention time of 4.7 min corresponding to an approximate equivalent spherical cell diameter of 0.8 microm. Cell suspensions were amended with increasing concentrations of U to establish an adsorption isotherm and with fixed U concentrations at varying pH to establish the pH dependence of sorption. A linear sorption isotherm was determined for U solution concentrations of 0.2-16 microM, maximum U sorption occurred at pH 5. A high molecular weight compound, presumably a cell exudate, was identified by Fl FFF-ICPMS. This cell exudate complexed U, and at elevated pH, the exudate appeared to have a greater affinity for U than cell surfaces. Thus, Fl FFF interfaced with ICPMS detection is a powerful analytical technique for metal sorption studies with bacteria; analysis can be carried out on small sample volumes (25 microL) and additional speciation information can be gained because of the versatile Fl FFF separation range and multielement detection capabilities of ICPMS.

Adsorption↗
PubMed2004

Infrared spectroscopic study on the thermal decomposition of external and internal gelation products of simulated mixed oxide nuclear fuel.

The thermal decomposition of urania-ceria gel corresponding to the composition U(0.7)Ce(0.3)O(2+x) obtained through external and internal gelation routes were studied using infrared spectroscopy (IR). In the case of externally gelated compound, the gel decomposes with the release of H2O and NH3 below 500 degrees C. A part of the NH3 released is entrapped in the solid and above 500 degrees C self reduction occurs in which U(VI) in the gel is reduced to U3O8. The decomposition products were identified to be U3O8 and CeO2. In the case of internally gelated compound, decomposition similar to the one for externally gelated compound occurred below 500 degrees C. Above 500 degrees C the carbon present in the gel reduced U(VI) to UO2 which formed solid solution with CeO2 around 650 degrees C.

Cerium↗
PubMed2002

Structural and density functional studies of uranium(III) and lanthanum(III) complexes with a neutral tripodal N-donor ligand suggesting the presence of a U-N back-bonding interaction.

The crystal structures of two trisiodide octacoordinated uranium(III) complexes of tris[(2-pyrazinyl)methyl]amine (tpza), which differ only by the ligand occupying the eighth coordination site (thf or MeCN), and of their lanthanum(III) analogues have been determined. In the acetonitrile adducts the M-N(pyrazine) distances are very similar for U(III) and La(III), while the U-N(acetonitrile) distance is 0.05 A shorter than the La-N(acetonitrile) distance. In the [M(tpza)I(3)(thf)] complexes in which the monodentate acetonitrile ligand, a weak pi-acceptor ligand, is replaced by a thf molecule, a sigma-donor only, the mean value of the distance U-N(pyrazine) is 0.05 A shorter than the mean value of the La-N(pyrazine) distance. Since we are comparing isostructural compounds of ions with very similar ionic radii, these differences indicate the presence of a stronger M-N interaction in the U(III) complexes and therefore suggest the presence of a covalent contribution to the U-N bonding. The selectivity of the tpza ligand toward U(III) complexation (with respect to that of La(III)) in the presence of sigma-donor-only ligands has been quantified by the value of K(U(tpza))/K(La(tpza)) measured to be 3.3 +/- 0.5. The analysis of the metal-N-donor ligand bonding was carried out by a quasi-relativistic density functional theory study on small model compounds, of formula I(3)M-L (M = La, Nd, U; L = acetonitrile, pyrazine) and I(3)M-(pyrazine)(3) (M = La, U). The structural data obtained from geometry optimizations on these systems reproduce experimental trends, i.e., a decrease in the M-N distance from La to U, combined with an increase of the C-N distance in the acetonitrile derivatives. A detailed orbital analysis carried out on the resulting optimized complexes did not reveal any orbital interaction between the trivalent lanthanide cations (Ln(3+)) and the N-donor ligands. In contrast, a back-donation electron transfer from 5f U(3+) orbitals to the pi* virtual orbital of the ligand was observed for both acetonitrile and pyrazine. Evaluation of the total bonding energy between the MI(3) and L fragments shows that this orbital interaction leads to a stabilization of the uranium(III) system compared to the lanthanide species.

Journal Article↗
PubMed1993

Ca(2+)-blockable, poorly selective cation channels in the apical membrane of amphibian epithelia. Tetracaine blocks the UO2(2+)-insensitive pathway.

We examined the effect of the local anesthetic tetracaine on the Ca(2+)-blockable, poorly selective cation channels in the isolated skin of Rana temporaria and the urinary bladder of Bufo marinus using noise analysis and microelectrode impalements. Experiments with frog skin demonstrated that mucosal concentrations of the compound up to 100 microM did not affect the Na+ current through type S channels (slowly fluctuating, UO2(2+)-blockable channels) and the associated noise. On the other hand, 20 microM mucosal tetracaine already suffices to inhibit approximately 50% of the current carried by Cs+ and Na+ through channel type F (fast fluctuating, UO2(2+)-insensitive channel) and So of the associated Lorentzian component. With 100 microM of the inhibitor the current and So values were reduced by at least 70-80%. The time course of the response to serosal tetracaine was markedly slower and the effects on the current and So were smaller. Possible effects on the basolateral K+ conductance were excluded on the basis of the lack of response of transepithelial K+ movements to 100 microM tetracaine. UO2(2+) and tetracaine together blocked the poorly selective cation pathways almost completely. Moreover, both agents retain their inhibitory effect in the presence of the other. In toad urinary bladder, the Ca(2+)-blockable channel is also tetracaine blockable. The concentration required for half-maximal inhibition is approximately 100 microM in SO4(2-) and approximately 20 microM in Cl-. The data with tetracaine complement those obtained with UO2(2+) and support the idea that the Ca(2+)-blockable current proceeds through two distinct classes of cation channels. Using tetracaine and UO2(2+) as channel-specific compounds, we demonstrated with microelectrode measurements that both channel types are located in the granulosum cells.

Animals↗
PubMed2005

Heat shock proteins and acquired resistance to uranium nephrotoxicity.

Previous studies have demonstrated that prior exposures to uranium can produce acquired resistance to uranium nephrotoxicity. In this study, the potential role for heat shock proteins (Hsps) in acquired resistance to uranium nephrotoxicity was explored. Pretreatment of male Sprague-Dawley rats with a conditioning dose of uranyl acetate (5 mg/kg, i.p.) was found to diminish the severity of proximal convoluted tubule necrosis and azotemia produced by a subsequent, higher uranyl acetate dose (10 mg/kg, i.p., 10 days after the conditioning dose). Kidney homogenates from rats euthanized at the end of the conditioning period were found to contain elevated levels of Hsp25, Hsp32, and Hsp70i, but not Hsc70. Immunochemical staining of renal sections for Hsp25 and Hsp70i revealed that these proteins were prominently expressed in tubular epithelial cells in uranyl acetate pretreated animals. Morphological characteristics and staining for proliferating cell nuclear antigen (PCNA) indicated that the cells expressing high levels of Hsps were regenerating. In RK3E and LLC-PK1 renal epithelial cells in culture, Hsp induction by thermal pretreatment did not afford protection from uranyl acetate cytotoxicity. Further, treatment of RK3E and LLC-PK1 cells with uranyl acetate did not result in induction of Hsps, as occurs with other nephrotoxic heavy metals. These observations suggest that while stress proteins are elevated in acquired resistance to uranyl acetate in vivo, they are not responsible for diminished uranium nephrotoxicity but are an epiphenomenon of tubular epithelial regeneration.

Animals↗