Early Pregnancy Exposure to Rare Earth Elements and Risk of Gestational Diabetes Mellitus: A Nested Case-Control Study.

Objective: The extensive use of rare earth elements (REEs) in many technologies was found to have effects on human health, but the association between early pregnancy exposure to REEs and gestational diabetes mellitus (GDM) is still unknown. Methods: This nested case-control study involved 200 pregnant women with GDM and 200 healthy pregnant women from the Peking University Birth Cohort in Tongzhou. We examined the serum concentrations of 14 REEs during early pregnancy and analyzed their associations with the risk of GDM. Results: When the elements were considered individually in the logistic regression model, no significant associations were found between REEs and GDM, after adjusting for confounding variables (P > 0.05). In weighted quantile sum (WQS) regression, each quartile decrease in the mixture index for REEs resulted in a 1.67-fold (95% CI: 1.12-2.49) increased risk of GDM. Neodymium (Nd), Praseodymium (Pr), and Lanthanum (La) were the most important contributors in the mixture. Conclusion: The study findings indicated that early pregnancy exposure to lower levels of REE mixture was associated with an increased risk of GDM, and Nd, Pr, and La exhibited the strongest effects in the mixture.

EVALUATION OF DOSE IN SLEEP BY MATTRESS CONTAINING MONAZITE.

Some companies in Korea have sold beds which contain a processed product containing monazite powder. Consumers may receive external exposure by radiation emitted by progeny radionuclides in uranium and thorium, and internal exposure through the breathing of radon progeny radionuclides produced in the decay chain. Thus, in this study, age specific dose conversion factors (mSv y-1 Bq-1) by external exposure and dose conversion factors by internal exposure (mSv y-1 per Bq m-3) were derived. Besides, a dose assessment program were developed to calculate dose by taking into account real conditions. And the age specific dose was evaluated using the radioactive concentration measured by the NSSC. As a results, external exposure was assessed to get effective doses in the range of 0.00086 to 0.0015 mSv y-1 by external exposure and a committed effective doses in the range of 1.3 to 12.26 mSv y-1 by internal exposure for all age groups.

Rare earths exposure and male infertility: the injury mechanism study of rare earths on male mice and human sperm.

The weight; testis/body coefficient; levels of LDH, SDH, SODH, G-6PD, and testosterone; cell cycle; and cell apoptosis of the male mice were influenced after being treated with 200 mg/[kg/day] of rare earths suspension for 3 weeks. The "Raman fingerprints" of the human sperm DNA exposed to 0.040 mg/ml CeCl3 were very different from those of the untreated; the Raman bands at 789 cm(-1) (backbone phosphodiester), PO4 backbone at 1,094 cm(-1), methylene deformation mode at 1,221 cm(-1), methylene deformation mode at 1,485 cm(-1), and amide II at 1,612 cm(-1), of which intensities and shifts were changed, might be the diagnostic biomarkers or potential therapeutic targets. The injury mechanism might be that the rare earths influence the oxidative stress and blood testosterone barrier, tangle the big biomolecule concurrently, which might cause the testicular cells and vascular system disorder and/or dysfunction, and at the same time change the physical and chemical properties of the sperm directly.

Effect of low and chronic radiation exposure: a case-control study of mental retardation and cleft lip/palate in the monazite-bearing coastal areas of southern Kerala.

A population-based 1:3 age-matched case-control study was conducted during 2006-2009 to assess the role of high-level natural radiation (>1 mSv/year) on congenital mental retardation and cleft lip/palate in the southwest coastal area of Kerala. Dosimetry was carried out in the house where parents resided during conception and the subsequent two trimesters of pregnancy of the study subject. Conditional logistic regression did not suggest any statistically significant association of either mental retardation (n = 445) or cleft lip/palate (n = 116) with high-level natural radiation. The odds of mental retardation and cleft lip/palate among those exposed to high-level natural radiation relative to normal levels of natural background radiation (≤1 mSv/year) were 1.26 (95% CI: 0.91-1.73) and 0.56 (95% CI: 0.31-1.02), respectively, after controlling for gender and maternal age at birth of the study subject. The data did not suggest any dose-related trend in the risk of either mental retardation (P = 0.113) or cleft lip/palate (P = 0.908). Notwithstanding the use of a single dose estimate to reconstruct past radiation exposure and the complex etiology of congenital malformations, it may reasonably be concluded that the prevailing high-level natural radiation in the study area does not appear to increase the risk of either mental retardation or cleft lip/palate among offspring of parents staying in the area.

Long-term in vivo biodistribution imaging and toxicity of polyacrylic acid-coated upconversion nanophosphors.

Rare-earth upconversion nanophosphors (UCNPs) have become one of the most promising classes of luminescent materials for bioimaging. However, there remain numerous unresolved issues with respect to the understanding of how these nanophosphors interact with biological systems and the environment. Herein, we report polyacrylic acid (PAA)-coated near-infrared to near-infrared (NIR-to-NIR) upconversion nanophosphors NaYF(4):Yb,Tm (PAA-UCNPs) as luminescence probes for long-term in vivo distribution and toxicity studies. Biodistribution results determined that PAA-UCNPs uptake and retention took place primarily in the liver and the spleen and that most of the PAA-UCNPs were excreted from the body of mice in a very slow manner. Body weight data of the mice indicated that mice intravenously injected with 15 mg/kg of PAA-UCNPs survived for 115 days without any apparent adverse effects to their health. In addition, histological, hematological and biochemical analysis were used to further quantify the potential toxicity of PAA-UCNPs, and results indicated that there was no overt toxicity of PAA-UCNPs in mice at long exposure times (up to 115 days). The study suggests that PAA-UNCPs can potentially be used for long-term targeted imaging and therapy studies in vivo.

Albumin nanoshell encapsulation of near-infrared-excitable rare-Earth nanoparticles enhances biocompatibility and enables targeted cell imaging.

The use of traditional fluorophores for in vivo imaging applications is limited by poor quantum yield, poor tissue penetration of the excitation light, and excessive tissue autofluorescence, while the use of inorganic fluorescent particles that offer a high quantum yield is frequently limited due to particle toxicity. Rare-earth-doped nanoparticles that utilize near-infrared upconversion overcome the optical limitations of traditional fluorophores, but are not typically suitable for biological application due to their insolubility in aqueous solution, lack of functional surface groups for conjugation of biomolecules, and potential cytotoxicity. A new approach to establish highly biocompatible and biologically targetable nanoshell complexes of luminescent rare-earth-doped NaYF(4) nanoparticles (REs) excitable with 920-980 nm near-infrared light for biomedical imaging applications is reported. The approach involves the encapsulation of NaYF(4) nanoparticles doped with Yb and Er within human serum albumin nanoshells to create water-dispersible, biologically functionalizable composite particles. These particles exhibit narrow size distributions around 200 nm and are stable in aqueous solution for over 4 weeks. The albumin shell confers cytoprotection and significantly enhances the biocompatibility of REs even at concentrations above 200 microg REs mL(-1). Composite particles conjugated with cyclic arginine-glycine-aspartic acid (cRGD) specifically target both human glioblastoma cell lines and melanoma cells expressing alpha(v)beta(3) integrin receptors. These findings highlight the promise of albumin-encapsulated rare-earth nanoparticles for imaging cancer cells in vitro and the potential for targeted imaging of disease sites in vivo.

Investigation on liver function among population in high background of rare earth area in South China.

The health effects of long-term ingestion of rare earth elements (REEs) on the villagers living in high-REE-background areas in South Jangxi Province, China were studied. Major health complaints from the REE area population included indigestion, diarrhea, abdominal distension, anorexia, weakness, and fatigue, especially after high-fat or high-protein intake. Liver function tests were conducted for adult villagers. Among them, 45 live in a heavy rare earth (HREE) area, 62 in a light rare earth (LREE) area, and 49 in the control area. Test results showed that serum total protein and globulin from both HREE and LREE areas, as well as albumin from the LREE area, were significantly lower (p < 0.01 - 0.01) compared to the results from the control area, whereas albumin from the HREE area showed no significant variance (p > 0.05). The chi-square test showed that Serum-glutamic pyruvic transaminase (SGPT) in both areas were not significant (p > 0.05), whereas the IgM in the HREE area was significantly elevated. It is our conclusion that long-term ingestion of REE affected activities of some digestive enzymes, causing malabsorption and indigestion, and might further lead to a low-protein effect for the villagers in the LREE area. However, the damage to the liver was rather mild. The elevation of IgM was probably the result of stimulation induced by the formation of a large amount of granules as a result of direct binding of REEs to globulin or albumin (combination of REEs with globulin or albumin).

[Effects of rare earth compounds on human peripheral mononuclear cell telomerase and apoptosis].

OBJECTIVE: To study the effects of rare earth exposure on human telomerase and apoptosis of human peripheral mononuclear cells (PBMNs). METHODS: Rare earth mine lot in Xunwu county, the biggest ion absorptive rare earth mine lot of China, was selected as the study site. Another village of Xunwu county, with comparable geological structure and social environment was selected as the control site. Thirty healthy adults were randomly selected from the study site as exposure group and another 30 healthy adults randomly selected from the control site as control group. The blood content of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, were determined by inductive coupled plasma-source mass spectrometry (ICP-MS). The total contents of rare earth elements in the blood were calculated. The TRAP and FCM assays were carried out to analyse the telomerase and apoptosis of human PBMNCs respectively. RESULTS: In the exposure group, the concentration of La, Ce, Dy and Y were significantly higher (P<0.001), and Pr, Nd, Sm, Gd and Yb were higher than those in the control group (P<0.05). The total content of rare earth in the blood of exposure group showed significant difference compared with control group (P<0.001). Telomerase activity in PBMNs of the exposure group was higher than that in the control group (P<0.05); there were 11 adults in the exposure group (30 adults) and 5 adults in control group (30 adults) showed positive telomerase activity. The average age of the exposure group was (38.69 +/- 8.02) years-old, while the control group was (40.45 +/- 9.02) years-old (P >0.05). It was found that there was a significant relationship between telomerase activity and the total content of rare earth elements (P <0.01). 3. The proportion of apoptosis was not different between the two groups (P >0.05), but the cells in the S-phase and G2-M phase were increased (P <0.01) in the exposed group. CONCLUSION: The telomerase activity of PBMNs in the rare earth elements exposed group was higher than that of the control group, and there is no effect on apoptotic rate of PBMNs, but may promote the diploid DNA replication, and increase the percentage of G2/M and S phase cells.

[Study on the effects of exposure to rare earth elements and health-responses in children aged 7-10 years].

OBJECTIVE: To study the effects of environmental exposure to rare earth elements (REEs) on health in children. METHODS: The level of physical growth and development, function of immune system, intelligence were chosen as the health-response indexes of children. Indicators for physical growth and development were measured. IgA, IgG, IgM and complement C3, C4 in blood serum were determined with turbidimeter measure, IgE were determined by chemiluminescence immunoassay (CLIA), lymphocyle subset CD3, CD4, CD8, CD4/CD8 and NK were determined by flowcytometry. Intelligence quotient (IQ) were examined with Drawing A Man Test in the children aged 7-10 years randomly sampled in the area containing rare earth (RE) ore and the control area in Xunwucounty, Jiangxi. Blood REEs were determined by inductively coupled plasma source mass pectrometry (ICP-MS). RESULTS: All 15 kinds of REEs were detected in each sample, the quantity of blood REEs of the children were lower in exposure group than in control group and in the rare earth area [(2.10 +/- 0.88)ng/g] was 1.73 times as that of the children in the control area [(1.26 +/- 1.35) ng/g]. The difference is significant (P < 0.01). The humoral immunity would be changed in the body of the children exposed to REEs, the quantity of IgM was lower in exposure group than in control group. The measuring result of T lymph subgroup of the children indicates: CD3, CD4, CD4/CD8 changed a lot. The percent of CD3, CD8 were significantly lower and CD4/CD8 was significantly higher in exposure group than in control group. The score of IQ was lower significantly in the exposure group than in the control. The percentage of high IQ decreased, the percentage of low IQ increased. Multiple regression analysis showed the variable of blood REEs in exposure to REEs group or those in the control group were introduced into the Vital capacity, blood pressure and IgM regression model. The distance from home to the RE area and either RE put in home influenced the score of children's IQ. CONCLUSION: The children aged 7-10 years in RE ore area may have higher REEs burden in the body, and exposure to REEs could have adverse influences in children.

Bioelectrical activity of the central nervous system among populations in a rare earth element area.

Auditory brainstem electric response (ABR) and somatosensory evoked potential (SEP) of 21 subjects (41 ears) among villagers in a rare earth element (REE) area in Gan County, Jiangxi, China, were studied. No difference in ABR between the subjects from the REE area and the control group was noted. However, the conduction detected by SEP from the median nerve to the thalamus (P15) was shortened (P < 0.05), especially to the first-grade primary somatosensory responsive region (S1) (P < 0.01) and the amplitude of S1 decreased (P < 0.05), indicating that REE was difficult to accumulate in the brainstem, but it was susceptible to cerebral cortex, thus causing sub-clinical damage. This condition was confirmed in the animal experiment. It was suggested that the toxicity through long-term intake of small doses of REE might not be negligible, and the hazard of REE environments should be investigated.

Geographical distribution of endomyocardial fibrosis in south Kerala.

BACKGROUND: Endomyocardial fibrosis (EMF) is a chronic heart disease confined to a few geographically specific locations within 15 degrees of the equator. Several aetiological hypotheses exist, among them filarial infection, eosinophilia, and toxic effect of the monazite element cerium from the soil. This study attempts to find out whether the pattern of distribution of EMF in south Kerala in India is consistent with the geochemical hypothesis. METHODS: From hospital records we identified all patients from south Kerala who had a confirmed diagnosis of EMF during the period 1978-1994. Our controls were patients from the southern districts diagnosed to have rheumatic heart disease (RHD) during the same period. We traced their residence address to the administrative subunit of taluk, and plotted the distribution of patients with EMF and RHD for each taluk in south Kerala. The taluks were then grouped into areas of high (> 4/100,000), medium (2.01-4/100,000), and low (< or = 2/100,000) density in each case. RESULTS: We identified an area of high density of EMF comprising four taluks near the coastline situated within the districts of Alapuzha, Kollam, and Pathanamthitta. Two coastal taluks in Kollam and Alapuzha districts are known areas of deposits of monazite elements in the state. Geographical distribution is not related to prevalence of filariasis and eosinophilia. CONCLUSION: Coexistence of high density of occurrence of EMF and deposits of monazite elements support the geochemical hypothesis.

Rare-earth pneumoconiosis: a new case.

A new case of rare-earth (RE) pneumoconiosis is described. The subject had worked as a photoengraver for 13 years and had not been exposed for 17 years. Chest X-ray showed a diffuse nodular pattern (q 2/3-ILO/1980). The patient was asymptomatic despite a restrictive spirometric impairment. The diagnosis derived from the finding, in the bronchoalveolar lavage fluid, of abnormal levels of La, Ce, Nd, Sm, Tb, Yb, and Lu. The presence of these elements was demonstrated by two methods: the neutron activation analysis and (as regards Ce alone) the X-ray energy spectrometry of mineral particles observed with electron microscope. Abnormal levels of rare earths were demonstrated also in the nails, suggesting an absorption of the RE from the lung.