Association between urinary metals and prostate-specific antigen in aging population with depression: a cross-sectional study.

Objective: This study aims to investigate the impact of depression and urinary metals on Prostate-Specific Antigen (PSA). Methods: Analysis was conducted on 1901 samples collected from the National Health and Nutrition Examination Survey (NHANES) database between 2001 and 2010. Analytical methods included stepwise multiple linear regression (MLR) analysis of the overall population's urinary metals and PSA relationship, analysis of urinary metals and PSA relationship in older adults and BMI subgroups, analysis of urinary metals and PSA relationship in the depressed population, and restricted cubic spline (RCS) analysis. A significance level of p < 0.05 was considered statistically significant. Results: In the stepwise multiple linear regression, beryllium (Be) showed a dose-response association with PSA (third quartile: ß = 0.05, 95%CI (0.02, 0.09); fourth quartile: ß = 0.07, 95%CI (0.02, 0.12), p trend = 0.048). Subgroup analysis indicated that in individuals aged >60, Be at Q4 level [ß = 0.09, 95%CI (0.05, 0.21)] exhibited a dose-response correlation with PSA. In the population with 25 ≤ BMI < 30, Be might more significantly elevate PSA, with Q4 level having a pronounced impact on PSA levels [ß = 0.03, 95%CI (0.02, 1.27)]. In the depressed population, urinary cadmium (Cd) levels showed a significant positive dose-response relationship, with Q4 level of Cd having the maximum impact on PSA [ß = 0.3, 95%CI (0.09, 0.49)]. Conclusion: Individuals exposed to beryllium (Be), especially the older adults and overweight, should monitor their PSA levels. In depressed patients, cadmium (Cd) levels may further elevate PSA levels, necessitating increased monitoring of PSA levels among males.

Comparative mathematical modeling of causal association between metal exposure and development of chronic kidney disease.

Background: Previous studies have identified several genetic and environmental risk factors for chronic kidney disease (CKD). However, little is known about the relationship between serum metals and CKD risk. Methods: We investigated associations between serum metals levels and CKD risk among 100 medical examiners and 443 CKD patients in the medical center of the First Hospital Affiliated to China Medical University. Serum metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). We analyzed factors influencing CKD, including abnormalities in Creatine and Cystatin C, using univariate and multiple analysis such as Lasso and Logistic regression. Metal levels among CKD patients at different stages were also explored. The study utilized machine learning and Bayesian Kernel Machine Regression (BKMR) to assess associations and predict CKD risk based on serum metals. A chained mediation model was applied to investigate how interventions with different heavy metals influence renal function indicators (creatinine and cystatin C) and their impact on diagnosing and treating renal impairment. Results: Serum potassium (K), sodium (Na), and calcium (Ca) showed positive trends with CKD, while selenium (Se) and molybdenum (Mo) showed negative trends. Metal mixtures had a significant negative effect on CKD when concentrations were all from 30th to 45th percentiles compared to the median, but the opposite was observed for the 55th to 60th percentiles. For example, a change in serum K concentration from the 25th to the 75th percentile was associated with a significant increase in CKD risk of 5.15(1.77,8.53), 13.62(8.91,18.33) and 31.81(14.03,49.58) when other metals were fixed at the 25th, 50th and 75th percentiles, respectively. Conclusions: Cumulative metal exposures, especially double-exposure to serum K and Se may impact CKD risk. Machine learning methods validated the external relevance of the metal factors. Our study highlights the importance of employing diverse methodologies to evaluate health effects of metal mixtures.

Comprehensive analysis of metal(loid)s and associated metal(loid) resistance genes in atmospheric particulate matter.

Despite global concerns about metal(loid)s in atmospheric particulate matter (PM), the presence of metal(loid) resistance genes (MRGs) in PM remains unknown. Therefore, we conducted a comprehensive investigation of the metal(loid)s and associated MRGs in PMs in two seasons (summer and winter) in Xiamen, China. According to the geoaccumulation index (Igeo), most metal(loid)s, except for V and Mn, exhibited enrichment in PM, suggesting potential anthropogenic sources. By employing Positive Matrix Factorization (PMF) model, utilizing a dataset encompassing both total and bioaccessible metal(loid)s, along with backward trajectory simulations, traffic emissions were determined to be the primary potential contributor of metal(loid)s in summer, whereas coal combustion was observed to have a dominant contribution in winter. The major contributor to the carcinogenic risk of metal(loid)s in both summer and winter was predominantly attributed to coal combustion, which serves as the main source of bioaccessible Cr. Bacterial communities within PMs showed lower diversity and network complexity in summer than in winter, with Pseudomonadales being the dominant order. Abundant MRGs, including the As(III) S-adenosylmethionine methyltransferase gene (arsM), Cu(I)-translocating P-type ATPase gene (copA), Zn(II)/Cd(II)/Pb(II)-translocating P-type ATPase gene (zntA), and Zn(II)-translocating P-type ATPase gene (ziaA), were detected within the PMs. Seasonal variations were observed for the metal(loid) concentration, bacterial community structure, and MRG abundance. The bacterial community composition and MRG abundance within PMs were primarily influenced by temperature, rather than metal(loid)s. This research offers novel perspectives on the occurrence of metal(loid)s and MRGs in PMs, thereby contributing to the control of air pollution.

[Application of metal cushion block combined with Jumbo cup in reconstruction of acetabular bone defect in revision of artificial hip joint].

OBJECTIVE: To investigate the application effect and imaging changes of metal cushion block combined with Jumbo cup in the reconstruction of acetabular bone defect after revision of artificial hip joint. METHODS: Retrospective analysis was made on the clinical data of 83 patients who underwent revision acetabular bone defect reconstruction of the artificial hip joint in our hospital from September 2019 to October 2021. They were divided into group A and group B according to different surgical methods. There were 42 patients in group A, including 26 males and 16 females, aged from 44 to 72 years old with an average of (60.57±4.62) years, who underwent revision with metal cushion block and Jumbo cup. There were 41 patients in group B, including 22 males and 19 females, aged from 42 to 71 years old with an average of (58.74±4.25) years, who underwent revision with metal cushion block and bone cement mortar cup. The operation related indexes, Harris hip function score and visual analogue scale (VAS) of pain before operation, 1 month and 12 month after operation were compared between two groups. The results of X-ray imaging examination (hip rotation center height, acetabular abduction angle, femoral eccentricity and imaging standard qualification rate) before and 12 month after operation were evaluated, and the incidence of complications was compared between two groups. RESULTS: There was no significant difference in operation time, intraoperative bleeding volume and postoperative drainage volume between two groups (P>0.05). Both groups were followed up for 12 to 36 months with an average of (25.36±3.59) months. The scores of pain, function, deformity and Harris' total score in the two groups at 1 month after operation were higher than those before operation (P<0.05), and the scores of pain, function, deformity, joint activity and Harris' total score in two groups at 1 year after operation were higher than those before operation and 1 month after operation (P<0.05), and the above scores in group A were higher than those in group B at 1 year after operation (P<0.05). The VAS of two groups decreased successively at 1 month and 1 year after operation (P<0.05), but there was no significant difference in both groups at each time point (P>0.05). The femoral eccentricity increased in both groups at 1 year after operation (P<0.05), and group A was higher than group B (P<0.05). The height of rotation center and acetabular abduction angle decreased in both groups at 1 year after operation (P<0.05), and the height of rotation center in group A was lower than that in group B (P<0.05), but there was no significant difference in acetabular abduction angle between two groups (P>0.05). The imaging qualification rate of group A was higher than that of group B (P<0.05). There was no significant difference in the incidence of adverse reactions between two groups (P>0.05). CONCLUSION: Metal cushion block combined with Jumbo cup in the treatment of acetabular bone defects can provide the hip joint function, and restore the hip joint rotation center, femoral eccentricity and acetabular abduction angle, with obvious clinical effect.

Associations among neighborhood walkability, metal exposure, and sex steroid hormone levels: Results from Hangzhou Birth Cohort Study â ¡.

BACKGROUND: Neighborhood walkability may influence maternal-fetal exposure to environmental hazards and maternal-fetal health (e.g., fetal growth restriction, reproductive toxicity). However, few studies have explored the association between neighborhood walkability and hormones in pregnant women. METHODS: We included 533 pregnant women from the Hangzhou Birth Cohort Study II (HBCS-II) with testosterone (TTE) and estradiol (E2) measured for analysis. Neighborhood walkability was evaluated by calculating a walkability index based on geo-coded addresses. Placental metals were measured using inductively coupled plasma mass spectrometry (ICP-MS). TTE and E2 levels in umbilical cord blood were measured using chemiluminescence microparticle immunoassay (CMIA). Linear regression model was used to estimate the relationship between the walkability index, placental metals, and sex steroid hormones. Effect modification was also assessed to estimate the effect of placental metals on the associations of neighborhood walkability with TTE and E2. RESULTS: Neighborhood walkability was significantly linked to increased E2 levels (P trend=0.023). Compared with participants at the first quintile (Q1) of walkability index, those at the third quintiles (Q3) had lower chromium (Cr) levels (ß = -0.212, 95% CI = -0.421 to -0.003). Arsenic (As), cobalt (Co), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), tin (Sn), and vanadium (V) were linked to decreased TTE levels, and cadmium (Cd) was linked to increased TTE levels. No metal was significantly associated with E2 levels in trend analysis. In the analysis of effect modification, the associations of neighborhood walkability with TTE and E2 were significantly modified by Mn (P = 0.005) and Cu (P = 0.049) respectively. CONCLUSION: Neighborhood walkability could be a favorable factor for E2 production during pregnancy, which may be inhibited by maternal exposure to heavy metals.

Computational modelling of supramolecular metallopeptide assemblies.

Among the important questions in supramolecular peptide self-assemblies are their interactions with metallic compounds and ions. In the last decade, intensive efforts have been devoted to understanding the structural properties of these interactions including their dynamical and catalytic impact in natural and de novo systems. Since structural insights from experimental approaches could be particularly challenging, computational chemistry methods are interesting complementary tools. Here, we present the general multiscale strategies we developed and applied for the study of metallopeptide assemblies. These strategies include prediction of metal binding site, docking of metallic moieties, classical and accelerated molecular dynamics and finally QM/MM calculations. The systems of choice for this chapter are, on one side, peptides involved in neurodegenerative diseases and, on the other, de novo fibrillar systems with catalytic properties. Both successes and remaining challenges are highlighted so that the protocol could be apply to other system of this kind.

Health risks of metals in soils and staple foods of the subsistence food gardens in the floodplains of Watut River, Papua New Guinea.

The health risks associated with the consumption of staples cultivated in the subsistence food gardens along the Watut River were investigated in Papua New Guinea. Twenty soil samples and twenty-nine samples of staple foods (including banana, taro, sweet potato, and Singapore taro) were collected from the food gardens following a three-day dietary recall survey. The concentration of metals (Cr, Cu, Pb, and Ni) was analyzed in the soil and food samples using Inductively Coupled Plasma Optical Emission Spectrophotometer. The descending order of mean metal concentration in the food garden soils is as follows: Cr > Cu > Ni > Pb. The concentration of Pb in all samples and Cr in 97% of staple foods exceeded the FAO/WHO permissible limits. Approximately 87% of adult consumers of bananas (Musa sp) were found to have estimated Cr and Pb ingestion levels exceeding the permissible daily tolerable intake of metals (0.2 and 0.21 mg day-1, respectively). Hazard index values from the staples analysis indicate that the consumption of bananas (9.40) poses the highest risk of non-carcinogenic effects on adults, followed by taro (7.32), sweet potato (6.13), and Singapore taro (4.30). The consumption of taro is dangerous due to cancer risk associated with the intake of excessive Ni (2.88E-02) and Cr (8.82E-03) in adults and children compared to banana, sweet potato, and Singapore taro. Non-carcinogenic hazards of metal ingestion were found to be pronounced in the younger population, while carcinogenic effects were more serious in adults. Urgent measures must be implemented to protect communities, especially children, from the dangerous effects of heavy metal ingestion through staples in the lower Watut region.

Metal Toxicity: Effects on Energy Metabolism in Fish.

Metals are dispersed in natural environments, particularly in the aquatic environment, and accumulate, causing adverse effects on aquatic life. Moreover, chronic polymetallic water pollution is a common problem, and the biological effects of exposure to complex mixtures of metals are the most difficult to interpret. In this review, metal toxicity is examined with a focus on its impact on energy metabolism. Mechanisms regulating adenosine triphosphate (ATP) production and reactive oxygen species (ROS) emission are considered in their dual roles in the development of cytotoxicity and cytoprotection, and mitochondria may become target organelles of metal toxicity when the transmembrane potential is reduced below its phosphorylation level. One of the main consequences of metal toxicity is additional energy costs, and the metabolic load can lead to the disruption of oxidative metabolism and enhanced anaerobiosis.

Cone-wedge anchored surgical templates for stackable metal guide: a novel technique.

OBJECTIVE: To address the instability in implant surgical guides, this technique proposes an alternative anchoring mechanism in the stackable metal surgical guides utilizing cone-wedge anchors for improved stability. METHODS: Postoperative implant position superimposed onto the preoperatively planned design using Mimics Medical 21.0 and Materialise Magics 24.0 to assess 3D coronal implant deviation, 3D apical implant deviation, and implant angular deviation. RESULTS: Postoperative cone-beam computed tomography (CBCT) revealed a high level of precision in the implant placement, with an average 0.97 mm deviation at implant coronal region, 1.56 mm at implant apexes, and 2.95° angular deviation. CONCLUSION: This technique introduces a novel cone-wedge anchoring mechanism to enhance the stability of stackable metal surgical guide templates, addressing inherent instability issues. The utilization of this approach significantly improves the accuracy of implant placement procedures.

Microbes vary strategically in their metalation of mononuclear enzymes.

Studies have determined that nonredox enzymes that are cofactored with Fe(II) are the most oxidant-sensitive targets inside Escherichia coli. These enzymes use Fe(II) cofactors to bind and activate substrates. Because of their solvent exposure, the metal can be accessed and oxidized by reactive oxygen species, thereby inactivating the enzyme. Because these enzymes participate in key physiological processes, the consequences of stress can be severe. Accordingly, when E. coli senses elevated levels of H2O2, it induces both a miniferritin and a manganese importer, enabling the replacement of the iron atom in these enzymes with manganese. Manganese does not react with H2O2 and thereby preserves enzyme activity. In this study, we examined several diverse microbes to identify the metal that they customarily integrate into ribulose-5-phosphate 3-epimerase, a representative of this enzyme family. The anaerobe Bacteroides thetaiotaomicron, like E. coli, uses iron. In contrast, Bacillus subtilis and Lactococcus lactis use manganese, and Saccharomyces cerevisiae uses zinc. The latter organisms are therefore well suited to the oxidizing environments in which they dwell. Similar results were obtained with peptide deformylase, another essential enzyme of the mononuclear class. Strikingly, heterologous expression experiments show that it is the metal pool within the organism, rather than features of the protein itself, that determine which metal is incorporated. Further, regardless of the source organism, each enzyme exhibits highest turnover with iron and lowest turnover with zinc. We infer that the intrinsic catalytic properties of the metal cannot easily be retuned by evolution of the polypeptide.

Supramolecular deep eutectic solvent: a powerful tool for pre-concentration of trace metals in edible oil.

The utilization of supramolecular deep eutectic solvent eddy-assisted liquid-liquid microextraction utilizing 2-hydroxypropyl ß-cyclodextrin (SUPRADES) has been identified as a successful method for pre-enriching Cu, Zn, and Mn in vegetable oil samples. Determination of each element was conducted by inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion of metal-enriched phases. Various parameters were examined, including the composition of SUPRADES species [2HP-ß-CD: DL-lactic acid], a cyclodextrin mass ratio of 20 wt%, a water bath temperature of 75 °C, an extractor volume of 800 µL, a dispersant volume of 50 µL, and an eddy current time of 5 min. Optimal conditions resulted in extraction rates of 99.6% for Cu, 105.2% for Zn, and 101.5% for Mn. The method exhibits a broad linear range spanning from 10 to 20,000 µg L-1, with determination coefficients exceeding 0.99 for all analytes. Enrichment coefficients of 24, 21, and 35 were observed. Limits of detection ranged from 0.89 to 1.30 µg L-1, while limits of quantification ranged from 3.23 to 4.29 µg L-1. The unique structural characteristics of the method enable the successful determination of trace elements in a variety of edible vegetable oils.

Associations of a toenail metal mixture with attention and memory in the Gulf long-term follow-up (GuLF) study.

BACKGROUND: Research on metal-associated neurodegeneration has largely focused on single metals. Since metal exposures typically co-occur as combinations of both toxic and essential elements, a mixtures framework is important for identifying risk and protective factors. This study examined associations between toenail levels of an eight-metal mixture and attention and memory in men living in US Gulf states. METHODS: We measured toenail concentrations of toxic (arsenic, chromium, lead, and mercury) and essential (copper, manganese, selenium, and zinc) metals in 413 non-smoking men (23-69 years, 46 % Black) from the Gulf Long-Term Follow-Up (GuLF) Study. Sustained attention and working memory were assessed at the time of toenail sample collection using the continuous performance test (CPT) and digit span test (DST), respectively. Associations between toenail metal concentrations and performance on neurobehavioral tests were characterized using co-pollutant adjusted general linear models and Bayesian Kernel Machine Regression. RESULTS: Adjusting for other metals, one interquartile range (IQR) increase in toenail chromium was associated with a 0.19 (95 % CI: -0.31, -0.07) point reduction in CPT D Prime score (poorer ability to discriminate test signals from noise). One IQR increase in toenail manganese was associated with a 0.20 (95 % CI, -0.41, 0.01) point reduction on the DST Reverse Count (fewer numbers recalled). Attention deficits were greater among Black participants compared to White participants for the same increase in toenail chromium concentrations. No evidence of synergistic interaction between metals or adverse effect of the overall metal mixture was observed for either outcome. CONCLUSIONS: Our findings support existing studies of manganese-related memory deficits and are some of the first to show chromium related attention deficits in adults. Longitudinal study of cognitive decline is needed to verify chromium findings. Research into social and chemical co-exposures is also needed to explain racial differences in metal-associated neurobehavioral deficits observed in this study.

Source-specific geochemical and health risk assessment of anthropogenically induced metals in a tropical urban waterway.

Thorough deliberation is necessary to safeguard the tropical urban streams near the shoreline from human interference, as it is becoming a notable environmental danger. Consequently, an in-depth study was carried out on a significant urban waterway located on the southern seashore of Bangladesh, which is positioned in the Bengal delta, renowned as the largest delta in the globe. The current investigation assesses the potential health hazards associated with trace metals (Hg, Cu, As, Pb, Ni, Zn, Cd, Cr, Fe, and Mn) and uses chemometric analysis to determine where they originate. Likewise geochemical methods are used to analyze the levels of trace metal enrichment and pollution in the sediments of the river. Almost all of the elements' mean concentrations were observed to be within the standard limits. The findings not only demonstrate the extent of trace metal contamination but also the health threats that it poses to the public (male, female, and children) by polluting the sediment. For all age groups of people, the hazard index was <1, suggesting there was no non-carcinogenic threat. Regardless of age and sex, exposure occurred in descending order: ingestion > dermal > inhalation. Total carcinogenic risk (TCR) values for males, females, and children were 1.45E-05, 1.56E-05, and 1.34E-04, respectively, recommending that children are at greater vulnerability than adults. The geochemical approach and chemometric analysis corroborate the human-induced impact of trace metal loading in the sediment of the waterway, which is predominantly caused by the oil industry, domestic garbage, and untreated waste discharge.

Holistic perilous index-based environmental appraisal of Metal(oid)s in the sole coral-bearing island of northeastern bay of Bengal.

This study aimed to evaluate the concentration, distribution, along with the environmental and human health impact of eight heavy metals-Pb, Cr, Cu, Cd, Zn, Mn, Ni, and As-on St. Martin's Island in the northeastern Bay of Bengal, and in doing so to help implement new legislations to protect the island. Focusing on the island's significance as a tourist destination, with seafood being a prominent dietary component, three sample types (sediment, seawater, and crustaceans) were selected for a comprehensive assessment, considering seasonal variations. Concentration of metals was observed to be lower than the established standards in sediment samples, but in seawater samples, Pb, Cr, Cd and Zn were higher than US-EPA values for natural marine water. The metals displayed a decreasing trend of Zn > Ni > Pb > Cu > Mn > As > Cd > Cr in crustacean samples for both seasons. Crustacean samples displayed higher metal concentrations in winter than in monsoon. Pb exceeded the maximum allowable limit for crustaceans with a concentration of about 3 and 4 mg kg-1 in monsoon and winter respectively; being more than 6-8 times the standard for Bangladesh which is only about 0.5 mg kg-1. Health indices displayed that although adults may suffer less from carcinogenic/non-carcinogenic health effects, the risks are far greater for children. For both age groups, As and Ni displayed possibilities of developing cancer. Principal Component Analysis (PCA)shed light on the sources of metals and showed that most of them were from anthropogenic sources. Overall, this study found that the quality of the environment of the island was better in comparison to previous studies made before the pandemic, and so, if the trend continues, it may lead to a better environment for the organisms around the island and help to keep the negative physiological impacts from the consumption of these organisms to a minimal.

Effect of acute exposure to settleable atmospheric particulate matter emitted by the steel industry on hematology and innate immunity of fat snook (Centropomus parallelus).

The steel industry is a significant worldwide source of atmospheric particulate matter (PM). Part of PM may settle (SePM) and deposit metal/metalloid and metallic nanoparticles in aquatic ecosystems. However, such an air-to-water cross-contamination is not observed by most monitoring agencies. The region of Vitoria City is the main location of iron processing for exports in Brazil, and it has rivers, estuaries, and coastal areas affected by SePM. We have evaluated the effects of SePM on a local representative fish species, the fat snook, Centropomus parallelus. After acclimation, 48 fishes (61.67 ± 27.83 g) were individually exposed for 96 h to diverse levels of SePM (0.0, 0.01, 0.1 and 1 g/L-1). The presence of metals in the blood and several blood biomarkers were analyzed to evaluate the impact of SePM on stress signaling, blood oxygen transport capacity, and innate immune activity. Metal bioaccumulation was measured from blood in two separately analyzed compartments: intracellular (erythrocytes plus white blood cells) and extracellular (plasma). The major metals present at all contamination levels in both compartments were Fe and Zn, followed by Al and Cu, plus traces of 'Emerging metals': Ba, Ce, La, Rb, Se, Sr, and Ti. Emerging metals refer to those that have recently been identified in water as contaminants, encompassing rare earth elements and critical technology elements, as documented in previous studies (See REEs and TCEs in Cobelo-García et al., 2015; Batley et al., 2022). Multivariate analysis revealed that SePM had strong, dose-dependent correlations with all biomarker groups and indicated that blood oxygen-carrying capacity had the highest contamination responsiveness. Metal contamination also increased cortisol and blood glucose levels, attesting to increased stress signaling, and had a negative effect on innate immune activity. Knowledge of the risks related to SePM contamination remains rudimentary. However, the fact that there was metal bioaccumulation, causing impairment of fundamental physiological and cellular processes in this ecologically relevant fish species, consumed by the local human population, highlights the pressing need for further monitoring and eventual control of SePM contamination.

Fragmentation of polypropylene into microplastics promoted by photo-aging; release of metals, toxicity and inhibition of biodegradability.

The widespread presence of microplastics (MP) in water represents an environmental problem, not only because of the harmful effects of their size and potential to vector other pollutants, but also because of the release of additives, degradation products and residues contained in the polymer matrix. The latter includes metallic catalysts, which are often overlooked. This study focuses on the photo-aging of polypropylene (PP) and the resulting structural changes that promote its fragmentation microplastics (PP-MPs) and release of metals, as well as the resulting toxicity of leachates and their potential to inhibit biodegradation of organics in water. The pristine, photo-aged and waste PP are ground under the same regime to assess susceptibility to fragmentation. Obtained PP-MPs are submitted to leaching tests; the release of organics and metals is monitored by Total Organic Carbon (TOC) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis, respectively. The leachates are assessed for their toxicity against Vibrio fischeri, Daphnia magna and Pseudokirchneriella subcapitata and their influence on the biodegradability of the glucose solution. Photo-aging induced changes in the crystallinity and morphology of the PP and manifested in the abundance of smaller MPs, as revealed by the particle size distribution. In the case of pristine PP, all particles were > 100 µm in size, while aged PP yielded significant mass fraction of MPs <100 µm. The toxicity of leachates from aged PP-MPs is higher than that of pristine and exhibits a positive correlation with portion of metals released. The biodegradability of glucose is strongly inhibited by PP-MPs leachates containing a mixture of metals in trace concentrations.

[Association of metal/metalloids exposure with abnormal liver function among occupational population in a mining area of Hunan Province:a prospective study].

OBJECTIVE: To investigate the association of metals/metalloids exposure with risk of liver disfunction among occupational population in Hunan Province, and to explore the potential dose-response relationship. METHODS: In 2017, a mining area in Hunan Province was chosen as the research site, and eligible workers were recruited as study subjects. General demographic characteristics, levels of 23 metals/metalloids in plasma and urine, and liver function index(total bilirubin(TBIL), alanine amino transferase(ALT), globulin(GLB) and γ-glutamyl transferase(GGT)) were obtained by questionnaire, physical examination and laboratory tests. Participants were followed up in 2018, 2019 and 2020 respectively. Cox proportional risk model was used to evaluate the relationship between metal/metalloids exposure and risk of liver disfunction, and dose-response relationship curves were plotted by using the restricted cubic spline function. RESULTS: A total of 891 employees were recruited in the study, 576(65.0%)were aged ≤45 years, 832(93.4%) were male and 530(59.5%) worked as smelters. After adjusting various factors such as age, gender, BMI, type of work, education, smoking, alcohol consumption, diet, stress, medical history, exercise and tea consumption, positive correlations were found between plasma tungsten(HR=4.90, 95%CI 1.17-20.48) and urinary barium(HR=1.07, 95%CI 1.02-1.12) levels with abnormally elevated TBIL levels. Additionally, a significant association was observed between plasma thallium and the risk of elevated ALT levels(HR=11.15, 95%CI 1.97-63.29). CONCLUSION: Plasma tungsten and thallium, along with barium found in urine, are risk factors for the development of abnormally elevated liver function indices in occupational groups.

Elevated cobalt levels in metal-on-polyethylene knee megaprostheses: a prospective 1-year cohort study of 56 patients with hip and knee megaprostheses.

BACKGROUND AND PURPOSE: Concerns have emerged regarding elevated levels of cobalt and chromium in patients with metal-on-metal megaprostheses. This prospective study aims to identify systemic cobalt and chromium levels in metal-on-polyethylene knee and hip megaprostheses and their associations with other factors. METHODS: 56 patients underwent knee or hip megaprosthesis surgery at 2 sarcoma centers. Serum cobalt and chromium levels were measured preoperatively and thrice within the first year using inductively coupled plasma mass spectrometry. RESULTS: A statistically significant difference in serum cobalt levels (1.4 ppb; 95% confidence interval [CI] 0.0-3.3) was observed 1 year after knee megaprosthesis surgery compared with preoperative levels. In contrast no difference in chromium levels was observed after 1 year compared with preoperative levels (0.05 ppb; CI 0.0-0.8). An association between younger age, higher eGFR, and increased cobalt levels was observed. No significant correlations were found between ion levels and resection length or the number of modular connections. CONCLUSION: We found elevated serum ion levels in metal-on-polyethylene knee megaprostheses in contrast to metal-on-polyethylene hip megaprostheses. Furthermore, a positive correlation between cobalt and chromium levels, and between cobalt and eGFR was identified, along with a negative correlation between cobalt and age. This study highlights the importance of monitoring systemic cobalt and chromium levels in patients with megaprostheses.

Catalytic Metal Ion-Substrate Coordination during Nonenzymatic RNA Primer Extension.

Nonenzymatic template-directed RNA copying requires catalysis by divalent metal ions. The primer extension reaction involves the attack of the primer 3'-hydroxyl on the adjacent phosphate of a 5'-5'-imidazolium-bridged dinucleotide substrate. However, the nature of the interaction of the catalytic metal ion with the reaction center remains unclear. To explore the coordination of the catalytic metal ion with the imidazolium-bridged dinucleotide substrate, we examined catalysis by oxophilic and thiophilic metal ions with both diastereomers of phosphorothioate-modified substrates. We show that Mg2+ and Cd2+ exhibit opposite preferences for the two phosphorothioate substrate diastereomers, indicating a stereospecific interaction of the divalent cation with one of the nonbridging phosphorus substituents. High-resolution X-ray crystal structures of the products of primer extension with phosphorothioate substrates reveal the absolute stereochemistry of this interaction and indicate that catalysis by Mg2+ involves inner-sphere coordination with the nonbridging phosphate oxygen in the pro-SP position, while thiophilic cadmium ions interact with sulfur in the same position, as in one of the two phosphorothioate substrates. These results collectively suggest that during nonenzymatic RNA primer extension with a 5'-5'-imidazolium-bridged dinucleotide substrate the interaction of the catalytic Mg2+ ion with the pro-SP oxygen of the reactive phosphate plays a crucial role in the metal-catalyzed SN2(P) reaction.

Dependence of n-Type Metal-Oxide Gas Sensor Response on the Pressure of Oxygen and Reducing Gases.

The adsorption of oxygen and its reaction with target gases are the basis of the gas detection mechanism by using metal oxides. Here, we present a theoretical analysis of the sensor response, within the ionosorption model, for an n-type polycrystalline semiconductor. Our goal of our work is to reveal the mechanisms of gas sensing from a fundamental point of view. We revisit the existing models in which the sensor response presents a power-law behavior with a reducing gas partial pressure. Then, we show, based on the Wolkenstein theory of chemisorption, that the sensor response depends not only on the reducing gas partial pressure but also on the oxygen partial pressure. We also find that the obtained sensor response does not explicitly depend on the grain size, and if it does, it is exclusively through the rate constants related to the involved reactions.