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PubMed2004

Characterization of 2,3-dihydroxyterephthalamides as M(IV) chelators.

The ligand N,N'-diethyl-2,3-dihydroxyterephthalamide (ETAM) has been characterized as a chelator for Zr(IV), Ce(IV), and Th(IV). The K(+) salts of the complexes [Zr(ETAM)(4)](4)(-), [Ce(ETAM)(4)](4)(-), and [Th(ETAM)(4)](4)(-) were prepared in a MeOH solution containing H(2)ETAM, the corresponding M(acac)(4), and 4 equiv of KOH. Single-crystal X-ray diffraction analyses are reported for K(4)[Zr(ETAM)(4)] (C2/c, Z = 8, a = 27.576(3) A, b = 29.345(3) A, c = 15.266(2) A, alpha = 90 degrees, beta = 118.688(4) degrees, gamma = 90 degrees ), [Me(3)BnN](4)[Th(ETAM)(4)] (P, Z = 2, a = 13.7570(3) A, b = 13.9293(3) A, c = 26.9124(6) A, alpha = 99.941(1) degrees, beta = 94.972(1) degrees, gamma = 103.160(1) degrees ), and the dimeric (NMe(4))(4)[Th(ETAM)(3)MeOH](2) (P2(1)/c, Z = 4, a = 18.2603(9) A, b = 18.5002(9) A, c = 19.675(1) A, beta = 117.298(1) degrees ). Solution thermodynamic studies were used to determine formation constants (log K(f) and esd) for Th(IV)-ETAM log K(110) =17.47(1), log K(120) = 13.23(1), log K(130) = 8.28(3), log K(140) = 6.57(6), and log beta(140) = 45.54(5). These results support the hypothesis that the terephthalamides are high-affinity chelators for the actinide(IV) ions and thus promising ligands for use in nuclear waste remediation.

Amides↗
PubMed1983

Lysosomal response of a murine macrophage-like cell line persistently infected with Coxiella burnetii.

The lysosomal response of a murine macrophage-like tumor cell line (J774) during persistent infection with Coxiella burnettii was examined. By using acid phosphatase as a lysosomal marker, it was shown that phagosome-lysosome fusion occurred in J774 cells persistently infected with C. burnetii. This observation was verified using thorium dioxide, an electron-dense compound that is sequestered in secondary lysosomes. The phagolysosomes contained viable replicating rickettsiae. Spectrofluorometric analysis indicated that the phagolysosomal pH of persistently infected cells was acidic. In attempts to correlate rickettsial survival with lysosome function, the activities of several lysosomal enzymes were assayed in both infected and uninfected cells. Activities of acid phosphatase and beta-acetylglucosaminidase were not significantly altered during infection. However, infected cells appeared to display slightly higher intracellular lysozyme, beta-glucuronidase, and beta-galactosidase activities.

Acid Phosphatase↗
PubMedDate not supplied

MRI appearance of thorotrast-induced cholangiocarcinoma in a case of thorotrastosis.

The case of a 71-year-old man with thorotrastosis and a cholangiocarcinoma detected by MRI is presented, and the radiographic appearance of the cholangiocarcinoma is discussed. We concluded that MR is more useful for detecting Thorotrast-induced liver tumors than US and CT, but CT is more useful for the detection of Thorotrast deposits.

Adenoma, Bile Duct↗
PubMed1995

Decorporation of thorium-228 from the rat by 3,4,3-LIHOPO and DTPA after simulated wound contamination.

1. With DTPA as a comparison, the siderophore analogue 3,4,3-LIHOPO has been examined for its ability to remove 228Th nitrate from the rat after subcutaneous (sc) and intramuscular (im) injection to simulate wound contamination. The commencement of treatment was delayed 30 min, 6 h or 1 d and the animals killed at 7 d. 2. In all cases 3,4,3-LIHOPO was appreciably more effective than DTPA although the efficacy of treatment and the relative effectiveness of the ligands decreased rapidly with their delay in administration. 3. Optimum removal with both ligands occurred when initial local administration at 30 min after exposure was followed by repeated intraperitoneal injection at 6 h, 1, 2 and 3 d. Under these conditions the body content of 228Th was reduced to 20% of controls after sc injection and 15% after im injection. The corresponding values using repeated DTPA administration were 80% and 54%. 4. It is concluded that 3,4,3-LIHOPO represents, potentially, a considerable advance on DTPA, the current agent of choice for the treatment of wounds contaminated by 228Th.

Animals↗
PubMed2002

Peteosthor - a medical disaster due to Radium-224A personal recollection.

Up to the end of World War II, there was no effective therapy against bone tuberculosis, and even today there is no treatment for ankylosing spondylitis. However, in the 1940s up to about 1956, radiotherapy with "Peteosthor" - a drug containing Thorium X ((224)Ra) as an effective compound - was introduced in Germany as a presumed cure and it maintained a central place in the treatment of these diseases. In 1948, I was entrusted to assess the new treatment. Animal studies and the clinical evaluation of the patients made me soon realise a number of severe adverse health effects which induced me to pronounce and subsequently repeat warnings against the intravenous administration of high doses of (224)Ra, especially because it was then administered predominantly to children and juveniles. As a consequence, this type of treatment was finally abandoned in 1956. But there remained a need to observe and document the resulting late health effects. Already in 1967, our initial follow-up study provided data for about 800 patients with exact information on the (224)Ra dose levels administered, administration schemes, and the resulting detrimental effects. A large number of bone sarcomas was the most severe consequence, but even today there is a broad spectrum of other grave health effects. A summary of the major scientific insights which have been achieved in the course of the still on-going epidemiological studies is part of this report.

Aged↗
PubMed1998

Determination of 226Ra in mineral drinking waters by alpha liquid scintillation with rejection of beta-gamma emitters.

The radiotoxicity of radium isotopes (especially the long-half-life 226Ra) requires their monitoring in drinking waters or nuclear wastes. We studied the applicability of the PERALS method of detection (photon electron rejecting alpha liquid scintillation) for radium measurement. This method combines alpha liquid scintillation with pulse shape analysis for beta rejection and specific chemical extractants included in the scintillating cocktail. Radium is separated by an extractive-scintillator cocktail called RADAEX containing 2-methyl-2-heptylnonanoic acid (HMHN) and dicyclohexano-21-crown-7 (Cy(2)21C7) as extractant molecules. The variation of the radium extraction has been studied relative to pH, salt concentrations, anion and cation effects, and the volume ratio between aqueous and organic phases. The main parameter affecting the radium extraction in mineral drinking water is its complexation by inorganic anions, especially sulfate. Due to the lack of thermodynamic data, some complexation constants had to be determined. For instance, the value reported in this paper for radium sulfate (log beta = 2.58 +/- 0.22) is in good agreement with that from the literature. The knowledge of complexation constants allows the determination of radium extraction recovery for any solution when the inorganic anion concentrations had been measured by capillary zone electrophoresis. The detection limit for this technique is found to be equal to 0.006 Bq.L-1 using only 6 mL of sample solution for analysis. Several French mineral waters have been studied and the results compared with determinations of uranium and thorium concentrations by ICPMS and time-resolved laser induced fluorescence (TRLIF).

Beta Particles↗
PubMed2006

Characterization of local Egyptian iron ores for use in radiation shielding concrete.

Petrographic, physical, chemical, mechanical, and radioactive characteristics tests were performed on magnetite, limonite, and hematite found in abundance in Egypt to determine their suitability for producing radiation shielding concrete. The contents of uranium and thorium were determined using instrumental neutron activation analysis and gamma spectroscopy. The results obtained using the two methods have shown satisfactory correlation. The tests confirm that magnetite and limonite are suitable as concrete aggregate while hematite is not because of its friable nature and high contents of uranium, thorium, and cobalt.

Ferric Compounds↗
PubMed1996

Use of INAA to study the determination of Se, Th, Zn, Co and Fe levels of yeast cells.

Differences in the effects of seleno-cystine (CySe)2, glutathione (GSH), Se(IV) [as SeO2] and Se(VI) [as (NH4)2SeO4] on Th(IV) [as Th(CO3)2] uptake by the cells, Saccharomyces cerevisiae, have been studied. The Th, Se, Zn, Co and Fe levels of the yeast cells were measured by instrumental neutron activation analysis. Results obtained show that the addition of Th alone to the culture medium resulting in the Th content of the cells and the Th level of the yeast slightly decreased during the incubation. The addition of Th in combination with GSH produced a higher decrease of the Th content in comparison with the single Th dosage. During the initial 48 h of the incubation the presence of Th and Se(VI) in the medium produced a decrease of the Th level of the cells in comparison with the addition of Th alone. (CySe)2 or SeO2 does not produce a regular change of the Th level of the cells. Th uptake by the yeast influenced the retention of Se in the cells. In fact, the Se levels of the cells were always significantly higher when the yeast was incubated in the medium containing Th and SeO2 or Se(VI). The enhance in the Se level of the cells rises with increasing concentrations of SeO2 in the culture medium. Th decreased the Se content of the yeast when the cells were incubated in the medium containing (CySe)2 and Th. GSH supply in combination with Th and SeO2 produced a very significant enhancement of the Se abundance in the cells in comparison with the single addition of SeO2. Se-compounds and/or Th dosages affected the Zn, Co and Fe contents of the cells. The Fe level of the yeast is below the quantitative detection limit of Fe when the cells were incubated in the medium containing Th.

Cobalt↗
PubMed2006

Trace elements in rock salt and their bioavailability estimated from solubility in acid.

In this study, 18 partly commercially available samples of rock salt from Austria, Germany, Pakistan, Poland, Switzerland, and Ukraine were investigated with respect to their content of trace elements using instrumental neutron activation analysis. Elements detected were Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, La, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, and Zn, some of them only in individual cases. An estimation of the bioavailability of these trace elements was performed by dissolving an equivalent of the sodium chloride samples in diluted hydrochloric acid (simulating stomach acid), filtering off the insoluble components, and analyzing the evaporated filtrate. It could be shown that in most cases bioactive trace elements like Fe can be found in rock salt in the form of almost insoluble compounds and are therefore not significantly bioavailable, whereas thorium, for example, was partly bioavailable in two cases. A significant contribution to the recommended daily intake of metal trace elements by using rock salt for nutrition can be excluded.

Biological Availability↗
PubMed2001

Rapid non-destructive quantitative estimation of urania/thoria in mixed thorium uranium di-oxide pellets by high-resolution gamma-ray spectrometry.

A non-destructive technique using high-resolution gamma-ray spectrometry has been standardised for quantitative estimation of uranium/thorium in mixed (ThO2-UO2) fuel pellets of varying composition. Four gamma energies were selected; two each from the uranium and thorium series and the time of counting has been optimised. This technique can be used for rapid estimation of U/Th percentage in a large number of mixed fuel pellets from a production campaign.

Radiation Monitoring↗
PubMed2003

Validation of the integrity of a HEPA filter system.

The objective of this study was to establish a delayed air sampling method to verify the integrity of an existing HEPA filter system in a ventilated fume hood. (238U,232Th)O2 microspheres were generated to fabricate cement nuclear fuel pellets in a HEPA-filtered hood. To comply with the air effluent concentration limits by NRC, the capture efficiency of the HEPA filter was examined. An in-line isokinetic air sampling system was installed downstream of the HEPA filter. Utilizing a gas flow proportional counter, 212Pb was used as a surrogate to indicate any possible penetration of the (238U,232Th)O2 particles through the HEPA filter. Based on the experimental results, this delayed sampling method proved to be an easy and effective way to validate the integrity of the HEPA filter.

Air Pollutants, Radioactive↗
PubMed2001

[Selective excitation spectra and energy level structure of Dy3+:ThO2 crystal].

Dy3+:ThO2 crystal was grown by the flux technique for the first time. The emission spectra, excitation spectra and fluorescence decay curves were measured and discussed. By using emission spectra obtained under selective dye laser excitation at 12 K, together with the crystal-field theory, the site symmetry of Dy3+ ions in ThO2 was determined as C3 nu and its energy level structure was tabulated. The lifetime of radiative level 4F9/2 was also determined as 0.40 ms.

Chemical Phenomena↗
PubMed2000

Ras gene mutations in vinyl chloride-induced liver tumours are carcinogen-specific but vary with cell type and species.

Previous studies have shown that a high proportion (5/6) of human liver angiosarcomas (ASL) associated with exposure to vinyl chloride (VC) contains a GC-->AT mutation at the Ki-ras codon 13. This mutation, however, has not been found in 5 ASL or 2 hepatocellular carcinomas (HCC) induced in rats by VC. These 2 HCC did contain a mutation at codon 61 of the Ha-ras gene. In order to extend this study and further explore the mechanisms of tumour induction, an additional 6 ASL and 6 HCC induced in rats by VC were analysed for ras gene point mutations, as well as 10 rat and 10 murine ASL induced by vinyl fluoride (VF), and 5 ASL, 6 Kupffer cell sarcomas, 4 HCC and 2 cholangiocellular carcinomas induced by Thorotrast in rats. Tumour DNA was analysed by PCR-SSCP and direct sequencing. None of the rodent ASL contained a mutation at codon 13 of the Ki-ras gene showing that the ras gene mutational pattern is species-specific. The CAA-->CTA mutation, previously found at codon 61 of the Ha-ras gene in rat HCC, was observed in 5 further VC-induced HCC but was not detected in the Thorotrast-induced HCC, suggesting carcinogen-specificity. This mutation was also absent in VC-induced ASL, which supports the cell-specificity of the ras mutational pattern in chemically induced tumours. No predominant mutation was detected in VF- and Thorotrast-induced tumours. Thus, a given mutation in a tumour may be carcinogen-specific but also depend on the species and the cell type.

Animals↗
PubMed1977

Angiosarcoma of the liver: an epidemiologic survey.

Diagnosed from 1970 through 1975, the annual incidence rate for angiosarcoma of the liver among residents of New York State (excluding New York City) was 0.25 per million. A case-control study indicated that direct exposure to arsenic, vinyl chloride (VC), and thorium dioxide was a significantly important factor in the etiology of this disorder (P less than 0.02). Direct exposure to these chemicals could not be demonstrated for 19 (73%) of the 26 study patients. The fact that 5 of these patients lived nearer to VC fabrication or polymerization plants than did their matched controls lent some support to the hypothesis that indirect modes of exposure, not specifically related to occupation, might be important in the etiology of this disorder.

Adolescent↗