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PubMedDate not supplied

Thorium and actinium polyphosphonate compounds as bone-seeking alpha particle-emitting agents.

The present study explores the use of alpha-particle-emitting, bone-seeking agents as candidates for targeted radiotherapy. Actinium and thorium 1,4,7,10 tetraazacyclododecane N,N',N'',N''' 1,4,7,10-tetra(methylene) phosphonic acid (DOTMP) and thorium-diethylene triamine N,N',N'' penta(methylene) phosphonic acid (DTMP) were prepared and their biodistribution evaluated in conventional Balb/C mice at four hours after injection. All three bone-seeking agents showed a high uptake in bone and a low uptake in soft tissues. Among the soft tissue organs, only kidney had a relatively high uptake. The femur/kidney ratios for 227Th-DTMP, 228-Ac-DOTMP and 227Th-DOTMP were 14.2, 7.6 and 6.0, respectively. A higher liver uptake of 228Ac-DOTMP was seen than for 227Th-DTMP and 227Th-DOTMP. This suggests that some demetallation of the 228Ac-DOTMP complex had occurred. The results indicate that 225Ac-DOTMP, 227Th-DOTMP and 227Th-DTMP have promising properties as potential therapeutic bone-seeking agents.

Actinium↗
PubMed2000

[Cytogenetic effects of separate and combined effect of thorium-232 and potassium nitrates on Tradescantia (clone 02)].

Under both separate and combined influence of 232nd-nitrate and potassium nitrate a study was made of the yield of somatic mutation frequencies, the level of morphologically abnormal cells and the loss of reproduction integrity in the stamen hairs of Tradescantia (clone 02). All investigated concentrations of 232nd-nitrate and potassium nitrate exerted statistically significant genotoxic effects and increased the level of morphological cell abnormalities in the stamen hairs of Tradescantia. Also, 0.36 mg/l 232nd and 0.51 mg/l KNO3 concentrations cause a statistically significant loss of reproduction integrity in the stamen hair. The combined action of 232nd-nitrate and potassium nitrate in all investigated concentrations and parameters causes a statistically significant effect.

Mutation↗
PubMed2001

Synthesis and characterization of six new quaternary actinide thiophosphate compounds: Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6)(,) K(10)Th(3)(P(2)S(7))(4)(PS(4))(2), and A(5)An(PS(4))(3), (A = K, Rb, Cs; An = U, Th).

Six new actinide metal thiophosphates have been synthesized by the reactive flux method and characterized by single-crystal X-ray diffraction: Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6) (I), K(10)Th(3)(P(2)S(7))(4)(PS(4))(2) (II), K(5)U(PS(4))(3) (III), K(5)Th(PS(4))(3) (IV), Rb(5)Th(PS(4))(3) (V), and Cs(5)Th(PS(4))(3) (VI). Compound I crystallizes in the monoclinic space group P2(1)/c with a = 33.2897(1) A, b = 14.9295(1) A, c = 17.3528(2) A, beta = 115.478(1) degrees, Z = 8. Compound II crystallizes in the monoclinic space group C2/c with a = 32.8085(6) A, b = 9.0482(2) A, c = 27.2972(3) A, beta = 125.720(1) degrees, Z = 8. Compound III crystallizes in the monoclinic space group P2(1)/c with a = 14.6132(1) A, b = 17.0884(2) A, c = 9.7082(2) A, beta = 108.63(1) degrees, Z = 4. Compound IV crystallizes in the monoclinic space group P2(1)/n with a = 9.7436(1) A, b = 11.3894(2) A, c = 20.0163(3) A, beta = 90.041(1) degrees, Z = 4, as a pseudo-merohedrally twinned cell. Compound V crystallizes in the monoclinic space group P2(1)/c with a = 13.197(4) A, b = 9.997(4) A, c = 18.189(7) A, beta = 100.77(1) degrees, Z = 4. Compound VI crystallizes in the monoclinic space group P2(1)/c with a = 13.5624(1) A, b = 10.3007(1) A, c = 18.6738(1) A, beta = 100.670(1) degrees, Z = 4. Optical band-gap measurements by diffuse reflectance show that compounds I and III contain tetravalent uranium as part of an extended electronic system. Thorium-containing compounds are large-gap materials. Raman spectroscopy on single crystals displays the vibrational characteristics expected for [PS(4)](3)(-), [P(2)S(7)](4-), and the new [P(3)S(10)](5)(-) building blocks. This new thiophosphate building block has not been observed except in the structure of the uranium-containing compound Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6).

Journal Article↗
PubMed2001

Dosimetric models for thorium and practical problems in assessing intakes.

An overview is given of the models recommended by the International Commission on Radiological Protection (ICRP) for assessing intakes and doses, and summarises biokinetic data obtained after the deposition of different chemical compounds of thorium in the rat lung. The results emphasise the importance of using material-specific data rather than default reference values for absorption into blood. The limitations of external monitoring of the chest or urine analysis are discussed, and comments made on alternative strategies for radiological protection of the worker.

Administration, Inhalation↗
PubMed2005

Uptake and distribution of natural radioactivity in wheat plants from soil.

The uptake of naturally occurring uranium, thorium, radium and potassium by wheat plant from two morphologically different soils of India was studied under natural field conditions. The soil to wheat grain transfer factors (TF) were calculated and observed to be in the range of 4.0 x 10(-4) to 2.1 x 10(-3) for 238U, 6.0 x 10(-3) to 2.4 x 10(-2) for 232Th, 9.0 x 10(-3) to 1.6 x 10(-2) for 226Ra and 0.14-3.1 for 40K. Observed ratios (OR) of radionuclides with respect to calcium have been calculated to explain nearly comparable TF values in spite of differences in soil concentration of the different fields. They also give an idea about the discrimination exhibited by the plant in uptake of essential and nonessential elements. The availability of calcium and potassium in soil for uptake affects the uranium, thorium and radium content of the plant. The other soil factors such as illite clays of alluvial soil which trap potassium in its crystal lattice and phosphates which form insoluble compounds with thorium are seen to reduce their availability to plants. A major percentage (54-75%) of total 238U, 232Th and 226Ra activity in the plant is concentrated in the roots and only about 1-2% was distributed in the grains, whereas about 57% of 40K activity accumulated in the shoots and 16% in the grains. The intake of radionuclides by consumption of wheat grains from the fields studied contributes a small fraction to the total annual ingestion dose received by man due to naturally existing radioactivity in the environment.

Aluminum Silicates↗
PubMed1986

Effects of a very low dose rate of chronic ionizing radiation on the division potential of human embryonic lung fibroblasts in vitro.

Among the various parameters that are supposed to play a role in aging at the cellular level, the "free radical theory" involves biochemical modifications that can be induced by radiation. Human embryonic lung fibroblasts were serially subcultivated at low density under chronic low dose rate irradiation (40 mrad/day) and in a normal environment. Irradiation increases cell attachment and the population doubling/day throughout their entire in vitro lifespan. Consequently, the doubling potential reached by irradiated cells was higher than that of control cultures. Finally, the total number of cells produced under chronic irradiation was 8-14 times higher than in a normal environment. These results are discussed with respect to the increased enzymatic activities (superoxidismutase, catalase, glutathion-reductase, G6PD) found in some irradiated organisms.

Cell Adhesion↗
PubMed2004

Investigations of the spin-Hamiltonian parameters for Er3+ at the Th4+ site in ThGeO4.

The spin-Hamiltonian (SH) parameters g factors g(parallel), g(perpendicular) and the hyperfine structure parameters A(parallel) and A(perpendicular) for Er3+ at the tetragonally distorted dodecahedral Th4+ site in ThGeO4 are theoretically investigated by using the perturbation formulas of the SH parameters for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the SH parameters from the second-order perturbation terms and the admixture of various energy levels are taken into account. The related crystal-field parameters are calculated from the geometrical relationship of the impurity center and the superposition model. Based on the studies, the lowest Kramers doublet is found to be Gamma7, rather than Gamma6 suggested in the previous work. The calculated SH parameters for Gamma7 doublet in this work are smaller than those obtained for Gamma6 doublet in the previous work and in good agreement with the observed values. The various contributions to the SH parameters are discussed.

Cations↗
PubMed2005

Investigation in thorium phosphate by NMR II-phosphorus dipolar networks.

With through space and through bond experiments in two-dimensional NMR we analyze the transformation from the thorium phosphate-hydrogen phosphate hydrate (TPHPH) to the beta form of the thorium phosphate diphosphate (beta-TPD) in relation with the phosphorus networks. These techniques are complementary: the through space coupling gives an insight on the dipolar phosphorus networks while the through bond coupling is particularly efficient in the detection of the P2O7 groups. With these experiments we show that in a first step, by heating the precursor TPHPH above 250 degrees C, it transforms into an alpha form of TPD. This transformation is due to the complete condensation of hydrogen phosphate groups HPO4 into P2O7 entities. By heating alpha-TPD above 950 degrees C it transforms into its well-known beta form. The alpha form is characterized by a hygroscopic behavior: some water molecules are present near the P2O7 groups that makes non-equivalent their phosphorus nuclei. PO4 dipolar networks are always present in the alpha form. The main effect of these PO4 and P2O7 units is to give the system a channel structure and the water enters in them.

Computer Simulation↗
PubMed2002

Direct quantification of human serum albumin in human blood serum without separation of gamma-globulin by the total internal reflected resonance light scattering of thorium-sodium dodecylbenzene sulfonate at water/tetrachloromethane interface.

A direct quantification of human serum albumin (HSA) in blood serum samples without separation is proposed based on the measurements of total internal reflected resonance light scattering (TIR-RLS) at water/tetrachloromethane (H(2)O/CCl(4)) interfaces. In the pH range of 6.37-6.59, the coadsorption of the binary complex of HSA-Th(IV) with sodium dodecylbenzene sulfonate occurs at the H(2)O/CCl(4) interface, forming an amphiphilic layer and displaying greatly enhanced TIR-RLS signals with the maximum peak located at 340-370 nm. The enhanced TIR-RLS intensity is in proportion to the HSA concentration in the range 0.15-1.0 micro gml(-1). The limit of detection is 14.4 ngml(-1). The contents of HSA in blood serum samples were determined with the recovery of 97.1-102.3% and RSD of 0.6-2.9%, which are identical to those obtained according to the spectrofluorimetric method using chrome azurol S.

Benzenesulfonates↗
PubMed1999

Complexes of Triamidoamines with the Early Actinides. Synthetic Routes to Monomeric Compounds of Tetravalent Uranium and Thorium Containing Halide and Amide Ligands.

The reaction of the lithiated triamidoamine [Li(3)(NN'(3))(THF)(3)] [NN'(3) = N(CH(2)CH(2)NSiMe(2)Bu(t))(3)] with AnCl(4) (An = U, Th) followed by sublimation gives monomeric [An(NN'(3))Cl]. Reaction of these complexes with SiMe(3)X (X = Br, I) gives [An(NN'(3))X]. The amido derivatives [An(NN'(3))(NEt(2))] are prepared from H(3)(NN'(3)) and [U(NEt(2))(4)] and from [Th(NN'(3))Cl] and [Li(NEt(2))]. In each case, the complexes [U(NN'(3))X] (X = Cl, Br, I, NEt(2)) are shown by X-ray crystallography to contain a triamidoamine ligand disposed with 3-fold symmetry about the metal center. The structures are distorted from trigonal bipyramidal by displacement of the uranium atoms out of the equatorial plane of the three amido nitrogen atoms by ca. 0.8 Å. The ligand backbone is distorted in such a manner as to cause the tert-butyldimethylsilyl groups to encircle the equatorial plane of the metal atom rather than surround the apical coordination site as is observed in the transition metal complexes of this type. Variation of the auxiliary ligand has little effect on the orientation, bond lengths, and angles within the (triamidoamine)uranium fragment. The tert-butydimethysilyl-substituted triamidoamine ligand is thus ideally suited for coordination to large metals since it stabilizes the formation of 3-fold symmetric structures while also allowing reactivity at the fifth coordination site.

Journal Article↗
PubMed2004

Metal-cation-mediated hydrolysis of phosphonoformate diesters: chemoselectivity and catalysis(1).

Hydrolyses in D(2)O (pD 1.7-3.1) of dimethyl (7), methyl phenyl (8), phenyl methyl (9), and diphenyl (10) phosphonoformate diesters are substantially accelerated by Ce(IV), Th(IV), Zr(IV), and Hf(IV) cations. Chemoselectivity is observed, whereby Zr(IV) and Hf(IV) principally direct P-OR hydrolysis, whereas Th(IV) and Ce(IV) mainly direct C-OR hydrolysis. Leaving group efficiency (OMe vs OPh) modulates the chemoselectivity. The metal cations also mediate further hydrolytic reactions of the initially produced phosphonoformate monoesters 14, 15, 18, and 20. The origins of the P-OR/C-OR selectivity are discussed in terms of the metal cation hydroxo species likely to be present in solution and the kinetics of the reactions.

Catalysis↗
PubMed2005

Infrared spectra and structures of the Th(OH)2 and Th(OH)4 molecules.

Thorium atoms react with H2O2, H2 + O2 mixtures, and H2O in excess argon to form the Th(OH)2 and Th(OH)4 molecules as minor and major products, respectively. The vibrational frequencies observed in the matrix infrared spectra are in excellent agreement with MP2 computed values, which confirms the identification of these highly ionic thorium hydroxide molecules. Our MP2 calculations converge to slightly bent and tetrahedral structures, respectively. This investigation reports the first evidence for pure actinide dihydroxide and tetrahydroxide molecules.

Deuterium↗
PubMed2001

Analysis of thorium and its progeny by gamma ray spectrometry and alpha track methods.

Samples originating from an EU sponsored intercomparison exercise were analysed by gamma ray spectrometry (a thorium solution sample, a zircon sand sample and a thorium ore sample). An alpha track method was also used to analyse the solution sample. The detection efficiency calibration for the gamma ray spectrometry measurements on the solid samples was established using an in-house standard of thorium nitrate. A GESPECOR Monte Carlo simulation program was utilised in the analysis of the solution sample. The in-house thorium nitrate standard was also used to prepare standards for the alpha track method. The relative differences between the 232Th activity concentration values determined in these intercomparison samples and values supplied by the NPL, UK, were found to be less than 5% when determined by the gamma ray spectrometry method and less than 8% when determined by the alpha track method.

Alpha Particles↗
PubMed1984

Radioactivity released from burning gas lantern mantles.

Gas lantern mantles contain thorium to produce incandescence when lantern fuel is burned on the mantle. Although only thorium is initially present on the mantle, the thorium daughters build up, some over a period of weeks and some over a period of years, and significant quantities of these daughters are present when the mantle is used. Some of these daughters are released when the lantern fuel is burned on the mantle. The amounts of radioactivity released during burning is studied by measuring the gamma radiation emitted by the daughters. Results of this study show that some of the radium (224Ra and 228Ra) and more than half the 212Pb and 212Bi is released during the first hour of a burn. The actual amounts release depend on the age of the mantle.

Environmental Exposure↗