Subchronic toxicity study of yttrium nitrate by 90-day repeated oral exposure in rats

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

The rare-earth yttrium induces cell apoptosis and autophagy in the male reproductive system through ROS-Ca2+-CamkII/Ampk axis

China has the world's largest reserves of rare earth elements (REEs), but widespread mining and application of REEs has led to an increased risk of potential pollution. Yttrium (Y), the first heavy REEs to be discovered, poses a substantial threat to human health. Unfortunately, little attention has been given to the impact of Y on human reproductive health. In this study, we investigated the toxic effects of YCl3 on mouse testes and four types of testicular cells, including Sertoli, Leydig, spermatogonial and spermatocyte cells. The results showed that YCl3 exposure causes substantial damage to mouse testes and induces apoptosis and autophagy, but not pyroptosis or necrosis, in testicular cells. Genome-wide gene expression analysis revealed that YCl3 induced significant changes in gene expression, with Ca2+ and mitochondria-related genes being the most significantly altered. Mechanistically, YCl3 exposure induced mitochondrial dysfunction in testicular cells, triggering the overproduction of reactive oxygen species (ROS) by impairing the Nrf2 pathway, regulating downstream Ho-1 target protein expression, and increasing Ca2+ levels to activate the CamkII/Ampk signaling pathway. Blocking ROS production or Ca2+ signaling significantly attenuates apoptosis and autophagy, while supplementation with Ca2+ reverses the suppression of apoptosis and autophagy by ROS blockade in testicular cells. Notably, apoptosis and autophagy induced by YCl3 treatment are independent of each other. Thus, our study suggests that YCl3 may impair the antioxidant stress signaling pathway and activate the calcium pathway through the ROS-Ca2+ axis, which promotes testicular cell apoptosis and autophagy independently, thus inducing testicular damage and impairing male reproductive function.

Yttrium chloride induces ferroptosis in cardiomyocytes via iron accumulation and triggers cardiac lipid peroxidation and inflammation that cause heart adverse events in mice

The growing presence of yttrium (Y) in the environment raises concern regarding its safety and toxicity. However, limited toxicological data are available to determine cardiotoxicity of Y and its underlying mechanisms. In the present study, yttrium chloride (YCl3) intervention with different doses was performed in male Kunming mice for the toxicological evaluation of Y in the heart. After 28 days of intragastric administration, 500 mg/kg·bw YCl3 induces iron accumulation in cardiomyocytes, and triggers ferroptosis through the glutathione peroxidase 4 (GPX4)/glutathione (GSH)/system Xc- axis via the inhibition of Nrf2 signaling pathway. This process led to cardiac lipid peroxidation and inflammatory response. Further RNA sequencing transcriptome analysis found that many genes involved in ferroptosis and lipid metabolism-related pathways were enriched. The ferroptosis induced by YCl3 in cardiomyocytes ultimately caused cardiac injury and dysfunction in mice. Our findings assist in the elucidation of the potential subacute cardiotoxicity of Y3+ and its underlying mechanisms.

Developmental immunotoxicity of maternal exposure to yttrium nitrate on BALB/c offspring mice

Yttrium is a typical heavy rare earth element with widespread use in numerous sectors. Only one previous study has indicated that yttrium has the potential to cause developmental immunotoxicity (DIT). Therefore, there remains a paucity of evidence on the DIT of yttrium. This study aimed to explore the DIT of yttrium nitrate (YN) and the self-recovery of YN-induced DIT. Dams were treated with 0, 0.2, 2, and 20 mg/kg bw/day YN by gavage during gestation and lactation. No significant changes were found in innate immunity between the control and YN-treated groups in offspring. In female offspring at postnatal day 21 (PND21), YN markedly inhibited humoral and cellular immune responses, the proliferative capacity of splenic T lymphocytes, and the expression of costimulatory molecules in splenic lymphocytes. Moreover, the inhibitory effect on cellular immunity in female offspring persisted to PND42. Unlike females, YN exposure did not change the adaptive immune responses in male offspring. Overall, maternal exposure to YN showed a strong DIT to offspring, with the lowest effective dose of 0.2 mg/kg in the current study. The toxicity of cellular immunity could persist throughout development into adulthood. There were sex-specific differences in YN-induced DIT, with females being more vulnerable.

The reproductive toxicity of yttrium nitrate in a two-generation study in Sprague-Dawley rats

OBJECTIVE

To evaluate the effects of yttrium nitrate on the development of the parent, offspring and third generation of Sprague-Dawley (SD) rats by using a two-generation reproductive toxicity test.

METHODS

The SD rats were randomly divided into 0 mg/kg group, 10.0 mg/kg group, 30.0 mg/kg group and 90.0 mg/kg group according to the different doses of yttrium nitrate administration. The reproductive toxicity of parent, offspring and third generation SD rats were compared.

RESULTS

The weight gains of F1a female rats and F2a female rats in the low-dose groups were significantly lower than those of the control groups (p < 0.05), the weight gains of F1a male rats in the medium-dose and high-dose groups were significantly lower than those of the control groups (p < 0.05), and the weight gains of F2a male rats in the low-dose, medium-dose and high-dose groups were significantly lower than those of the control groups (p < 0.05). In F0 male rats, the absolute weight and relative weight of the liver in the low-dose, middle-dose, and high-dose groups were significantly lower than those of the control group (p < 0.05). In F1b male rats, the absolute and relative weights of the liver in the medium-dose and high-dose groups were significantly lower than those of the control group (p < 0.05). In F2b male rats, the absolute and relative weights of the liver and spleen of the medium-dose and high-dose groups were significantly lower than those of the control group (p < 0.05). In F2a female rats, the absolute weight and relative weight of oviduct in the high-dose group were significantly lower than those in the control group (p < 0.05). The absolute and relative weights of lung, spleen, brain and uterus of F2b female rats in the high-dose group were higher than those of the control group (p < 0.05). But the pathological test results showed no hepatotoxicity. There was no statistically significant difference in sperm count and sperm motility between male rats in the yttrium nitrate administration groups and the control group (p > 0.05). There was no significant correlation between F0, F1a, F1b, F2a, F2b SD rats' reproductive organ lesions and the dose of yttrium nitrate.

CONCLUSION

Yttrium nitrate at a dose of 90 mg/kg has no reproductive toxicity to two generations of SD rats, but 30.0 mg/kg dose of yttrium nitrate is toxic to the liver weight of male two generations of SD rats, but no hepatotoxicity.

Hypertension risk is associated with elevated concentrations of rare earth elements in serum

BACKGROUND

Hypertension is a major contributor to cardiovascular morbidity and mortality, affecting over 17.1 million individuals worldwide. Environmental exposure such as toxic trace elements could be risk factors for hypertension, but the associations of toxic metal exposure with hypertension are not well understood.

METHODS

We recruited 400 volunteers consisting of 200 patients with hypertension (cases) and 200 healthy individuals without hypertension (controls). In the case or control group, half of the subjects came from the rare earth mining (REM) areas and the other half from non-REM areas. Serum levels of 8 rare earth elements (REEs) and 13 non-REEs were determined.

RESULTS

The concentrations of Ce and La were significant higher in the cases than in the controls in all comparisons. Serum concentrations of Mg, Mn, Dy, Ce and La were positively correlated with blood pressure, while those of concentrations K and Se were negatively correlated with blood pressure (p < 0.05). Compared with the lowest quartiles, participants in the highest quartiles of Sm, Gd, Dy, Yb, La and Ce had a 6.01-fold (95 % CI: 2.28, 15.8), 3.29-fold (95 % CI: 1.18, 9.16), 4.07-fold (95 % CI: 1.51,10.9), 7.83-fold (95 % CI: 2.78, 22.4), 20.00-fold (95 % CI: 5.48-72.9) and 6.13-fold (95 % CI: 2.13-17.6) increase in the probability of having hypertension respectively. Among all the detected metals, the univariate odds ratios (UORs) and adjusted odds ratios (AORs) of hypertension for highest vs. lowest quartile serum concentrations of Sm, Gd, Dy, Yb, La and Ce were significantly > 1 (p < 0.05), with the positive dose-response relationships observed between their serum levels and ORs associated with hypertension risk.

CONCLUSIONS

Collectively, there appears to be a positive correlation between hypertension and environmental exposure to REEs, especially La and Ce. Further studies are warranted to investigate the underlying mechanisms responsible for the risk.

Dietary Exposure Assessment of Rare Earth Elements in the Chinese Population

Rare earth elements (REEs) are widely found in foods. A high intake of REEs may have associations with adverse effects on human health. This study aimed to investigate the concentrations of REEs in foods in China and to assess the risk of dietary REEs exposure in the Chinese population. The mean concentrations of the total REEs in 27,457 food samples from 11 food categories ranged from 0.04 to 1.41 mg/kg. The daily mean dietary exposure of the total REEs was 1.62 μg/kg BW in the general Chinese population and ranged from 1.61 to 2.80 μg/kg BW in different sex-age groups. The high consumer exposure (95th percentile, P95) was 4.83 μg/kg BW, 9.38% of the temporary ADI (tADI) of REEs (51.5 μg/kg BW). None of the P95 exposure exceeded the tADI in all of the sub-groups. Lanthanum, cerium, and yttrium accounted for approximately 63% of the total exposure of the 16 REEs. The hazard index of 16 REEs was far below 1. Therefore, the health risk of dietary REEs exposure in the general Chinese population was low. No cumulative risk was found for the 16 REEs in China. The results indicate there was no need to stipulate the limits of REEs in foods.

Risk assessment of rare earth elements in fruits and vegetables from mining areas in China

Assessment of contaminated food through the dietary intake is essential for human health. To investigate the health risk of rare earth element (REE) exposure to fruits and vegetables in mining areas in China, we collected 288 fruit samples and 942 vegetable samples from four representative mining points (Bayan Obo in Inner Mongolia, Weishan in Shandong, Maoming in Guangdong, Longnan in Jiangxi) and their control areas. The content of REEs was determined by inductively coupled plasma-mass spectrometry (ICP-MS). The total REEs in fruits from mining and control areas were 12.90 μg kg^-1 and 11.89 μg kg^-1, and in vegetables were 92.90 μg kg^-1 and 62.38 μg kg^-1, and the difference was statistically significant in vegetables (P = 0.048). The drupes had more REE concentration in fruits (68.41 μg kg^-1, 16.90 μg kg^-1 in mining and control areas, respectively) (P < 0.01), and the leafy vegetables had more REE concentration in vegetables (245.81 μg kg^-1, 123.51 μg kg^-1 in mining and control areas, respectively) (P < 0.01). With the enrichment of light rare earth elements (LREE), the REE distribution patterns coincided in mining and control areas and different types of fruits and vegetables. The health risk assessment indicated that the estimated daily intakes (0.02-0.06 μg kg^-1 day^-1, 0.53-1.22 μg kg^-1 day^-1 for fruits and vegetables, respectively) were lower than the allowable daily intake value (60.4 μg kg^-1 day^-1). In mining areas, REEs obtained from fruits and vegetables were insufficient to cause health damage to human beings. However, sustained exposure to low REEs, especially for children, still needs attention.

Risk assessment of rare earth elements, antimony, barium, boron, lithium, tellurium, thallium and vanadium in teas

In recent years, a great intensification in the use of various elements especially in modern technology can be observed. However, the anthropogenic activities, including industrialisation, urbanisation or intensive agriculture, have led to the release of many of the elements into the environment. The consequence of the accumulation of the elements both in soil and water systems is their presence in the food chain. Inhalation and consumption of the contaminated food and beverages have been indicated as the main pathways of the exposure to many elements. Due to the fact, that tea is considered the second most popular beverage worldwide and its consumption is constantly increasing, it is crucial to evaluate the safety of the product, especially for toxic elements contamination. Thus, the aim of the project was to evaluate the contamination levels of rare earth elements (REEs) including lanthanides, scandium (Sc) and yttrium (Y) and also antimony (Sb), barium (Ba), boron (B), lithium (Li), tellurium (Te), thallium (Tl) and vanadium (V) in teas. Subsequently, the risk assessment was carried out. Additionally, the Fellowship provided hands-on training on the evaluation of applications of new biocides and participation in the science-based advises given to the Danish Food and Veterinary Administration, Danish Environment Protection Agency and Danish Medical Agency.

Biodegradable shape memory alloys: Progress and prospects

Shape memory alloys (SMAs) have a wide range of potential novel medical applications due to their superelastic properties and ability to restore and retain a 'memorised' shape. However, most SMAs are permanent and do not degrade in the body when used in implantable devices. The use of non-degrading metals may lead to the requirement for secondary removal surgery and this in turn may introduce both short and long-term health risks, or additional waste disposal requirements. Biodegradable SMAs can effectively eliminate these issues by gradually degrading inside the human body while providing the necessary support for healing purposes, therefore significantly alleviating patient discomfort and improving healing efficiency. This paper reviews the current progress in biodegradable SMAs from the perspective of biodegradability, mechanical properties, and biocompatibility. By providing insights into the status of SMAs and biodegradation mechanisms, the prospects for Mg- and Fe-based biodegradable SMAs to advance biodegradable SMA-based medical devices are explored. Finally, the remaining challenges and potential solutions in the biodegradable SMAs area are discussed, providing suggestions and research frameworks for future studies on this topic.

Effects of lanthanum nitrate on behavioral disorder, neuronal damage and gene expression in different developmental stages of Caenorhabditis elegans

Rare earth elements (REEs) are widely used in the industry, agriculture, biomedicine, aerospace, etc, and have been shown to pose toxic effects on animals, as such, studies focusing on their biomedical properties are gaining wide attention. However, environmental and population health risks of REEs are still not very clear. Also, the REEs damage to the nervous system and related molecular mechanisms needs further research. In this study, the L1 and L4 stages of the model organism Caenorhabditis elegans were used to evaluate the effects and possible neurotoxic mechanism of lanthanum(III) nitrate hexahydrate (La(NO₃)₃·6H₂O). For the L1 and L4 stage worms, the 48-h median lethal concentrations (LC₅₀s) of La(NO₃)₃·6H₂O were 93.163 and 648.0 mg/L respectively. Our results show that La(NO₃)₃·6H₂O induces growth inhibition and defects in behavior such as body length, body width, body bending frequency, head thrashing frequency and pharyngeal pumping frequency at the L1 and L4 stages in C. elegans. The L1 stage is more sensitive to the toxicity of lanthanum than the L4 stage worms. Using transgenic strains (BZ555, EG1285 and NL5901), we found that La(NO₃)₃·6H₂O caused the loss or break of soma and dendrite neurons in L1 and L4 stages; and α-synuclein aggregation in L1 stage, indicating that Lanthanum can cause toxic damage to dopaminergic and GABAergic neurons. Mechanistically, La(NO₃)₃·6H₂O exposure inhibited or activated the neurotransmitter transporters and receptors (glutamate, serotonin and dopamine) in C. elegans, which regulate behavior and movement functions. Furthermore, significant increase in the production of reactive oxygen species (ROS) was found in the L4 stage C. elegans exposed to La(NO₃)₃·6H₂O. Altogether, our data show that exposure to lanthanum can cause neuronal toxic damage and behavioral defects in C. elegans, and provide basic information for understanding the neurotoxic effect mechanism and environmental health risks of rare earth elements.

Efficient degradation of roxarsone and simultaneous in-situ adsorption of secondary inorganic arsenic by a combination of Co3O4-Y2O3 and peroxymonosulfate

Roxarsone (ROX), as one of aromatic organoarsenic compounds (AOCs), is extensively used in livestock industry, which tends to transform into high-toxic inorganic arsenic in environments. Herein, a bifunctional Co₃O₄-Y₂O₃, possessing extremely excellent catalytic and adsorption performance due to the synergy of Co₃O₄ and Y₂O₃, was designed and employed to activate peroxymonosulfate (PMS) for the elimination of ROX and the simultaneous in-situ adsorption of secondary inorganic arsenic, in which Co₃O₄ acted as the primary catalyst, and Y₂O₃ served as the main adsorbent. 50 μM (3.75 mg-As/L) of ROX was almost completely degraded, coupled with the conversion of As(III) to As(V) in the system of Co₃O₄-Y₂O₃ (0.2 g/L) and PMS (0.5 mM) within 15 min at initial pH 7. Meanwhile, > 99.3% of the secondary As(V) would be removed within 120 min. The reactive oxygen species (ROS) were identified to be ^•OH, SO₄^•-, and ¹O₂, which were responsible for the ROX degradation and the formation of As(V). Simultaneously, the produced As(V) were effectively adsorbed via the ligand/anion exchange with surface -OH and CO₃^2- anions of Co₃O₄-Y₂O₃. The possible degradation pathways of ROX were further proposed on the basis of the intermediates identification. Our findings may provide an insight into the degradation of AOCs and the simultaneous removal of secondary inorganic arsenic via the PMS activation with Co₃O₄-Y₂O₃.

Rare earth element lanthanum protects against atherosclerosis induced by high-fat diet via down-regulating MAPK and NF-κB pathways

Rare earth elements, which are extensively used in environmental protection, medicine, food, aerospace and other fields, have attracted widespread attention in recent years. However, the effect on atherosclerosis and its biological mechanism remains unclear. To elucidate these problems, here we performed a study that Apolipoprotein E-deficient mice were fed with high-fat diet to promote the development of atherosclerosis, meanwhile, mice were received 0.1, 0.2, 1.0, 2.0 mg/kg lanthanum nitrate (La(NO₃)₃) for 12 weeks. The results showed that La(NO₃)₃ prominently inhibited aorta morphological alternations by histopathological examination. Meanwhile, La(NO₃)₃ regulated serum lipids, including reducing total cholesterol and increasing high-density lipoprotein. Moreover, the oxidative stress was alleviated by La(NO₃)₃ intervention through enhancing superoxide dismutase and glutathione, and decreasing malondialdehyde levels. In addition, enzyme-linked immunosorbent assay analysis showed La(NO₃)₃ could ameliorate the dysfunction of vascular endothelium with declined endothelin-1 and increased prostacyclin. Furthermore, Western blot analysis indicated that La(NO₃)₃ significantly down-regulated inflammation-mediated proteins including phosphorylated p38 mitogen-activated protein kinases (p-p38 MAPK), monocyte chemo-attractant protein, intercellular adhesion molecule-1, nuclear factor-kappa B p65 (NF-κB p65), tumor necrosis factor-α, interleukin-6 and interleukin-1β, whereas up-regulated the inhibitor of NF-κB protein. In conclusion, La(NO₃)₃ ameliorates atherosclerosis by regulating lipid metabolism, oxidative stress, endothelial dysfunction and inflammatory response in mice. The potential mechanism associates with the inhibition of MAPK and NF-κB signaling pathways.

A mini-review of X-ray photodynamic therapy (XPDT) nonoagent constituents' safety and relevant design considerations

Conventional photodynamic therapy (PDT) has proved effective in the management of primary tumors and individual metastases. However, most cancer mortality arises from wide-spread multiple metastases. The latter has thus become the principal target in oncology, and X-ray induced photodynamic therapy (XPDT or PDTX) offers a great solution for adapting the PDT principle to deep tumors and scattered metastases. Developing agents capable of being excited by X-rays and emitting visible light to excite photosensitizers is based on challenging physical and chemical technologies, but there are fundamental biological limitations that are to be accounted for as well. In the present review, we have established eight major groups of safety determinants of NPs encompassing 22 parameters of clinical applicability of XPDT nanoparticulate formulations. Most, if not all, of these parameters can be accounted for and optimized during the design and development of novel XPDT nanoparticles.

Comparative study of toxicological assessment of yttrium oxide nano- and microparticles in Wistar rats after 28 days of repeated oral administration

Despite their enormous advantages, nanoparticles (NPs) have elicited disquiet over their safety. Among the numerous NPs, yttrium oxide (Y2O3) NPs are utilised in many applications. However, knowledge about their toxicity is limited, and it is imperative to investigate their potential adverse effects. Therefore, this study explored the effect of 28 days of repeated oral exposure of Wistar rats to 30, 120 and 480 mg/kg body weight (bw) per day of Y2O3 NPs and microparticles (MPs). Before initiation of the study, characterisation of the particles by transmission electron microscopy, dynamic light scattering, Brunauer-Emmett-Teller and laser Doppler velocimetry was undertaken. Genotoxicity was evaluated using the comet and micronucleus (MN) assays. Biochemical markers aspartate transaminase, alanine transaminase, alkaline phosphatase, malondialdehyde, superoxide dismutase, reduced glutathione, catalase and lactate dehydrogenase in serum, liver and kidney were determined. Bioaccumulation of the particles was analysed by inductively coupled plasma optical emission spectrometry. The results of the comet and MN assays showed significant differences between the control and groups treated with 120 and 480 mg/kg bw/day Y2O3 NPs. Significant biochemical alterations were also observed at 120 and 480 mg/kg bw/day. Haematological and histopathological changes were documented. Yttrium (Y) biodistribution was detected in liver, kidney, blood, intestine, lungs, spleen, heart and brain in a dose- and the organ-dependent manner in both the particles. Further, the highest levels of Y were found in the liver and the lowest in the brain of the treated rats. More of the Y from NPs was excreted in the urine than in the faeces. Furthermore, NP-treated rats exhibited much higher absorption and tissue accumulation. These interpretations furnish rudimentary data of the apparent genotoxicity of NPs and MPs of Y2O3 as well as the biodistribution of Y. A no-observed adverse effect level of 30 mg/kg bw/day was found after oral exposure of rats to Y2O3 NPs.

Concentrations of rare earth elements in maternal serum during pregnancy and risk for fetal neural tube defects

Rare earth elements (REEs) are ubiquitous in the environment. Animal experiments have shown that many REEs have adverse impacts on the health of fetuses. However, data from humans are scarce. In this study, we examined the associations between concentrations of 10 REEs in maternal serum and the risk for fetal neural tube defects (NTDs). The study included 200 pregnant women with pregnancies affected by NTDs and 400 pregnant women with healthy fetuses/infants. Fifteen REEs in maternal serum were assessed; 10 of them were detectable in over 60% of samples and were included in statistical analyses, including lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), terbium (Tb), dysprosium (Dy), lutetium (Lu), and yttrium (Y). When the elements were considered individually with the use of Logistic regression model, the risk for NTDs increased by 2.78-fold (1.25-6.17) and 4.31-fold (1.93-9.62) for La, and 1.52-fold (0.70-3.31) and 4.73-fold (2.08-10.76) for Ce, in the second and third tertiles, respectively, compared to the lowest concentration tertile. When Bayesian kernel machine regression was used to examine the joint effect of exposure to all 10 REEs, the risk for NTDs increased with overall levels of these REEs and the association between La and NTD risk remained when other nine elements were taken into consideration simultaneously. Taken together, this study shows that the risk for NTDs increases with La concentrations when single REEs are considered and with concentrations of all 10 REEs when these REEs are considered as a co-exposure mixture.

Subchronic toxicity of cerium nitrate by 90-day oral exposure in wistar rats

This study evaluated the subchronic toxicity of cerium nitrate and determined the no observed adverse effect level (NOAEL) in Wistar rats. In accordance with the Organization for Economic Co-operation and Development guidelines, cerium nitrate was orally administered to Wistar rats by gavage at 0, 0.2, 75, 150, and 300 mg/kg bw/day for 90 days, followed by 28 days of recovery period in the 300 mg/kg bw/day and the control groups. The following parameters were evaluated: mortality, abnormalities, body weight, food consumption, hematology, serum biochemistry, urinanalysis, gross necropsy and histopathology. At the end of the treatment, several significant changes were observed in the 300 mg/kg bw/day groups: relatively decreased mean body weight of males, increased LYMPH%, RET% and decreased NEUT%, RBC of the females, increased ALT, AST and decreased ALB, T-Bil, CHO, CK, LDH of males. Significantly decreased T-Bil, CHO, CK and LDH were also observed in males of the 150 mg/kg bw/day group. Pathological examination revealed that the incidences of foreign body granulomatous lesions in lungs were higher in the 150 and 300 mg/kg bw/day groups as compared with the control group. These findings were attributed to unexpected gavage exposure because the granuloma exhibited a bronchiole-derived distribution. Taken together, the NOAEL of cerium nitrate in Wistar rats is set to be 75 mg/kg bw/day in the present study.

Investigation of rare earth elements in urine and drinking water of children in mining area

To compare the contents of rare earth elements in urine and drinking water of children in the mining and control areas and evaluate the health risk of children in the mining area.Urine and drinking water of 128 children in the mining area and 125 children in the control area were collected from June to July 2015. The contents of rare earth elements were determined using inductively coupled plasma mass spectrometry.The detection rates of rare earth elements, including yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), and samarium (Sm), in the urine of children in the exposed group were all 100%, except for samarium (98%); the rates in the control group were 85.7%, 100%, 100%, 98%, 98%, and 59.2%, respectively, and the remaining elements were not detectable. The concentrations of Y, La, Ce, Pr, Nd, and Sm in the urine of children in the exposed group were significantly higher than that in the control group (P < .01). In addition, the composition ratio of lanthanum was higher than that in the control group. The detection rates of lanthanum and Ce in the drinking water of children in the exposed group were 1.44% and 0.72%, respectively. The others were not detectable; the rates in the control group were all 0%.The pollution caused by the presence of Y, La, Ce, Pr, Nd, and Sm in the mining area might affect the health of children in the area, but drinking water might not be the cause.

Global Deletome Profile of Saccharomyces cerevisiae Exposed to the Technology-Critical Element Yttrium

The emergence of the technology-critical-element yttrium as a contaminant in the environment raises concern regarding its toxicological impact on living organisms. The molecular mechanisms underlying yttrium toxicity must be delineated. We considered the genomic phenotyping of a mutant collection of Saccharomyces cerevisiae to be of particular interest to decipher key cellular pathways involved either in yttrium toxicity or detoxification mechanisms. Among the 4733 mutants exposed to yttrium, 333 exhibited modified growth, of which 56 were sensitive and 277 were resistant. Several functions involved in yttrium toxicity mitigation emerged, primarily vacuolar acidification and retrograde transport. Conversely, functional categories overrepresented in the yttrium toxicity response included cytoskeleton organization and endocytosis, protein transport and vesicle trafficking, lipid metabolism, as well as signaling pathways. Comparison with similar studies carried out using other metals and stressors showed a response pattern similar to nickel stress. One third of the identified mutants highlighted peculiar cellular effects triggered by yttrium, specifically those affecting the pheromone-dependent signaling pathway or sphingolipid metabolic processes. Taken together, these data emphasize the role of the plasma membrane as a hotspot for yttrium toxicity. The up-to-now lack of data concerning yttrium toxicity at the cellular and molecular levels makes this pioneer study using the model S. cerevisiae an excellent first basis for the assessment of yttrium toxicity toward eukaryotes.