Distribution, elimination, and renal effects of single oral doses of europium in rats

Insights into the effects of lanthanides on mammalian systems and potential applications

Lanthanides, a group of elements with unique chemical properties, have garnered significant attention for their varied biological effects, ranging from cytotoxic to protective, depending on concentration, cell type, and exposure conditions. This review provides a detailed examination of the biological interactions of lanthanides with mammalian systems, including humans, by exploring their impact on different cell lines and organisms. Through a systematic assessment of current research, this work highlights the dual nature of lanthanides, identifying them as both potential therapeutic agents and environmental toxins. Furthermore, it underscores the importance of understanding their mechanisms to mitigate health risks, particularly for those exposed occupationally or via environmental sources. The review concludes with an overview of knowledge gaps and future research directions necessary for unlocking the therapeutic potential of lanthanides while ensuring safety and sustainability in their applications.

ICRP Publication 141: Occupational Intakes of Radionuclides: Part 4

The 2007 Recommendations (ICRP, 2007) introduced changes that affect the calculation of effective dose, and implied a revision of the dose coefficients for internal exposure, published previously in the Publication 30 series (ICRP, 1979a,b, 1980a, 1981, 1988) and Publication 68 (ICRP, 1994b). In addition, new data are now available that support an update of the radionuclide-specific information given in Publications 54 and 78 (ICRP, 1989a, 1997) for the design of monitoring programmes and retrospective assessment of occupational internal doses. Provision of new biokinetic models, dose coefficients, monitoring methods, and bioassay data was performed by Committee 2 and its task groups. A new series, the Occupational Intakes of Radionuclides (OIR) series, will replace the Publication 30 series and Publications 54, 68, and 78. OIR Part 1 (ICRP, 2015) describes the assessment of internal occupational exposure to radionuclides, biokinetic and dosimetric models, methods of individual and workplace monitoring, and general aspects of retrospective dose assessment. OIR Part 2 (ICRP, 2016), OIR Part 3 (ICRP, 2017), this current publication, and the final publication in the OIR series (OIR Part 5) provide data on individual elements and their radioisotopes, including information on chemical forms encountered in the workplace; a list of principal radioisotopes and their physical half-lives and decay modes; the parameter values of the reference biokinetic models; and data on monitoring techniques for the radioisotopes most commonly encountered in workplaces. Reviews of data on inhalation, ingestion, and systemic biokinetics are also provided for most of the elements. Dosimetric data provided in the printed publications of the OIR series include tables of committed effective dose per intake (Sv per Bq intake) for inhalation and ingestion, tables of committed effective dose per content (Sv per Bq measurement) for inhalation, and graphs of retention and excretion data per Bq intake for inhalation. These data are provided for all absorption types and for the most common isotope(s) of each element. The online electronic files that accompany the OIR series of publications contains a comprehensive set of committed effective and equivalent dose coefficients, committed effective dose per content functions, and reference bioassay functions. Data are provided for inhalation, ingestion, and direct input to blood. This fourth publication in the OIR series provides the above data for the following elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), actinium (Ac), protactinium (Pa), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), and fermium (Fm).

Correlation of nasopharyngeal carcinoma with rare earth elements and the Epstein-Barr virus

The concentration and distribution of rare earth elements (REE) in nasopharyngeal carcinoma (NPC) were measured to investigate connections with tumor size, lymph node metastasis, clinical stages, and Epstein-Barr virus (EBV) infection. There were 30 patients with NPC who met the criteria for inclusion in the present study. The EBV copy number, as well as the concentration and distribution of REE, was analyzed. EBV was detected using reverse transcription-polymerase chain reaction, with the concentrations of REE in NPC tissues measured using inductively coupled plasma-tandem mass spectrometry. The mean values were used when comparing concentrations of REE in NPC tissues as the standard deviation of this parameter was the lowest. Light REE had the highest concentrations, followed by medium, and then heavy REE. The concentrations of REE decreased with increasing tumor size and with the presence of lymph node metastasis. The concentrations of REE gradually increased between stage II and IVa, but markedly decreased thereafter. The elements that exhibited the greatest decreases were terbium, holmium and ytterbium. Furthermore, the concentrations of REE in NPC were not associated with sex (r=0.301, P=0.106) or age (r=−0.011, P=0.955), and were negatively associated with EBV (r=−0.744, P<0.001). By contrast, the EBV copy number increased alongside advancements in clinical stage. Changes in the concentrations of REE in NPC were more prominent for medium and heavy elements. Additionally, alterations in the concentrations of heavy REE may affect the occurrence and development of NPC.

Risk assessment visualization of rubidium compounds: comparison of renal and hepatic toxicities, in vivo

Rubidium has been considered to be nontoxic. Its use includes thin film on glass deposition and as medical contrast medium. Recent technology innovations also involve the use of rubidium, but there is limited information about the biological effects of its various compounds. In the present risk assessment study, a series of rubidium compounds with different counter anions-acetate, bromide, carbonate, chloride, and fluoride-were orally administrated in a single dose to several groups of rats. Cumulative 24-h urine samples were obtained, and the levels of rubidium, fluoride, N-acetyl-β-D-glucosaminidase and creatinine were measured to evaluate possible acute renal effects. Daily samples of serum were also obtained to determine the levels of aspartate and alanine aminotransferases to assess possible acute hepatic effects. Urinary rubidium excretion recovery of 8.0-10.5% shows that urine can be a useful diagnostic tool for rubidium exposure. The present results reveal that rubidium shows different biological effects depending on the counter anion. A pattern of large significant NAG leakage and elevation of ALT observed in rats treated with anhydrous rubidium fluoride indicates renal and hepatic toxicities that can be attributed to fluoride. The techniques reported in this study will be of help to assess the potential risks of toxicity of rubidium compounds with a variety of anions.

Urinary monitoring of exposure to yttrium, scandium, and europium in male Wistar rats

On the assumption that rare earth elements (REEs) are nontoxic, they are being utilized as replacements of toxic heavy metals in novel technological applications. However, REEs are not entirely innocuous, and their impact on health is still uncertain. In the past decade, our laboratory has studied the urinary excretion of REEs in male Wistar rats given chlorides of europium, scandium, and yttrium solutions by one-shot intraperitoneal injection or oral dose. The present paper describes three experiments for the suitability and appropriateness of a method to use urine for biological monitoring of exposure to these REEs. The concentrations of REEs were determined in cumulative urine samples taken at 0-24 h by inductively coupled plasma atomic emission spectroscopy, showing that the urinary excretion of REEs is <2 %. Rare earth elements form colloidal conjugates in the bloodstream, which make high REEs accumulation in the reticuloendothelial system and glomeruli and low urinary excretion. The high sensitivity of inductively coupled plasma-argon emission spectrometry analytical methods, with detection limits of <2 μg/L, makes urine a comprehensive assessment tool that reflects REE exposure. The analytical method and animal experimental model described in this study will be of great importance and encourage further discussion for future studies.