Distribution and bioavailability of mercury in size-fractioned atmospheric particles around an ultra-low emission power plant in Southwest China

Ultra-low emission (ULE) technology retrofits significantly impact the particulate-bound mercury (Hg) emissions from coal-fired power plants (CFPPs); however, the distribution and bioavailability of Hg in size-fractioned particulate matter (PM) around the ULE-retrofitted CFPPs are less understood. Here, total Hg and its chemical speciation in TSP (total suspended particles), PM10 (aerodynamic particle diameter ≤ 10 µm) and PM2.5 (aerodynamic particle diameter ≤ 2.5 µm) around a ULE-retrofitted CFPP in Guizhou Province were quantified. Atmospheric PM2.5 concentration was higher around this ULE-retrofitted CFPP than that in the intra-regional urban cities, and it had higher mass Hg concentration than other size-fractioned PM. Total Hg concentrations in PM had multifarious sources including CFPP, vehicle exhaust and biomass combustion, while they were significantly higher in autumn and winter than those in other seasons (P < 0.05). Regardless of particulate size, atmospheric PM-bound Hg had lower residual fractions (< 21%) while higher HCl-soluble fractions (> 40%). Mass concentrations of exchangeable, HCl-soluble, elemental, and residual Hg in PM2.5 were higher than those in other size-fractioned PM, and were markedly elevated in autumn and winter (P < 0.05). In PM2.5, HCl-soluble Hg presented a significantly positive relationship with elemental Hg (P < 0.05), while residual Hg showed the significantly positive relationships with HCl-soluble Hg and elemental Hg (P < 0.01). Overall, these results suggested that atmospheric PM-bound Hg around the ULE-retrofitted CFPP tends to accumulate in finer PM, and has higher bioavailable fractions, while has potential transformation between chemical speciation.

Suppression of mercury methylation in soil and methylmercury accumulation in rice by dissolved organic matter derived from sulfur-rich rape straw

Straw amendment significantly enhances mercury (Hg) methylation and subsequent methylmercury (MeHg) bioaccumulation in Hg-contaminated paddy fields by releasing dissolved organic matter (DOM). This study comprehensively investigates the regulatory mechanisms of DOM and its different molecular weights derived from sulfur-rich rape straw (RaDOM) and composted rape straw (CRaDOM) applied in the rice-filling stage on soil MeHg production and subsequent bioaccumulation in rice grains. The results indicated that the amendment of RaDOM and CRaDOM significantly reduced soil MeHg content by 42.40-62.42%. This reduction can be attributed to several factors, including the suppression of Hg-methylating bacteria in soil, the supply of sulfate from RaDOM and CRaDOM, and the increase in the humification, molecular weight, and humic-like fractions of soil DOM. Additionally, adding RaDOM increased the MeHg bioaccumulation factor in roots by 27.55% while inhibiting MeHg transportation by 12.24% and ultimately reducing MeHg content in grains by 21.24% compared to the control group. Similarly, CRaDOM enhanced MeHg accumulation by 25.19%, suppressed MeHg transportation by 39.65%, and reduced MeHg levels in the grains by 27.94%. The assimilation of sulfate derived from RaDOM and CRaDOM into glutathione may be responsible for the increased retention of MeHg in the roots. Over the three days, there was a significant decrease in soil MeHg content as the molecular weight of RaDOM increased; conversely, altering the molecular weight of CRaDOM demonstrated an inverse trend. However, this pattern was not observed after 12 days. Applying sulfur-rich rape DOM can help mitigate MeHg accumulation in paddy fields by regulating the quality of soil DOM, sulfur cycling, and Hg-methylating bacteria.

Selenium-phosphorus modified biochar reduces mercury methylation and bioavailability in agricultural soil

Biochar is a frequently employed for solidifying and stabilizing mercury (Hg) contamination in soil. However, it often results in an elevated presence of soil methylmercury (MeHg), which introduces new environmental risks. Consequently, there is a necessity for developing a safer modified biochar for use in Hg-contaminated soil. This study employed sodium selenite (at a safe dosage for soil) and hydroxyapatite to modify straw biochar (BC) based on the interaction between selenium (Se) and phosphorus (P). This process led to the formation of Se-modified biochar (Se-BC), P-modified biochar (P-BC), and Se and P co-modified biochar (Se-P-BC). Additionally, solvent adsorption experiments and pot experiments (BC/soil mass ratio: 0.5 %) were conducted to investigate the impacts of these soil amendments on soil Hg methylation and bioavailability. Se and P co-modification substantially increased the surface area, pore volume, and Hg adsorption capacity of BC. BC treatment increased the simulated gastric acid-soluble Hg, organo-chelated Hg, and MeHg in the soil. Conversely, Se-P-BC significantly reduced these forms of Hg in the soil, indicating that Se-P-BC can transform soil Hg into less bioavailable states. Among the different biochar treatments, Se-P-BC exhibited the most pronounced reductions in soil MeHg, total Hg, and MeHg in water spinach, achieving reductions of 63 %, 71 %, and 70 %, respectively. The co-modification of Se and P displayed a synergistic reduction effect in managing soil Hg pollution, which is associated with the increase of available Se in the soil due to phosphorus addition. The significantly reduced dissolved organic carbon and the abnormally high SO42- concentration in the soil of Se-P-BC treatment also inhibited Hg methylation and bioavailability in the soil. In summary, Se-P-BC substantially increased reduction percentage in plant Hg content while mitigating the risk of secondary pollution arising from elevated soil MeHg.

Application potential of biofertilizer-assisted Pennisetum giganteum in safe utilization of mercury-contaminated paddy fields

High mercury (Hg) bioaccumulation in crops such as rice in Hg-contaminated areas presents a potential health hazard to humans and wildlife. To develop a safe alternative technique, bacillus-inoculated biofertilizer, citric acid, earthworms, and selenium-modified activated clay were compared for their ability to regulate Hg bioaccumulation in Pennisetum giganteum (P. giganteum). This biofertilizer significantly increased Bacillus sp. abundance in the soil by 157.12%, resulting in the removal of 27.52% of water-soluble Hg fractions through volatilization and adsorption mechanisms. The variation in bioavailable Hg in the soil significantly reduced the total Hg concentration in P. giganteum young leaves, old leaves, stems, and roots of P. giganteum by 74.14%, 48.08%, 93.72%, and 50.91%, respectively (p < 0.05), which is lower than the Chinese feed safety standard (100 ng g-1). The biofertilizer inhibitory potential was highly consistent with that of the selenium-modified activated clay. Biofertilizers significantly reduced the methylmercury concentration in various P. giganteum tissues (p < 0.05), whereas selenium-modified activated clay failed to achieve a comparable effect. This biofertilizer-assisted planting pattern can achieve an economic income quadruple that of the rice planting pattern in the Hg-contaminated paddy fields. Because of its significant environmental and financial applications, the biofertilizer-assisted planting pattern is expected to replace Hg-contaminated paddy fields.

The Effects of Different Soil Component Couplings on the Methylation and Bioavailability of Mercury in Soil

Soil composition can influence the chemical forms and bioavailability of soil mercury (Hg). However, previous studies have predominantly focused on the influence of individual components on the biogeochemical behavior of soil Hg, while the influence of various component interactions among several individual factors remain unclear. In this study, artificial soil was prepared by precisely regulating its components, and a controlled potted experiment was conducted to investigate the influence of various organic and inorganic constituents, as well as different soil textures resulting from their coupling, on soil Hg methylation and its bioavailability. Our findings show that inorganic components in the soils primarily exhibit adsorption and fixation effects on Hg, thereby reducing the accumulation of total mercury (THg) and methylmercury (MeHg) in plants. It is noteworthy that iron sulfide simultaneously resulted in an increase in soil MeHg concentration (277%). Concentrations of THg and MeHg in soil with peat were lower in rice but greater in spinach. A correlation analysis indicated that the size of soil particles was a crucial factor affecting the accumulation of Hg in plants. Consequently, even though fulvic acid activated soil Hg, it significantly increased the proportion of soil particles smaller than 100.8 μm, thus inhibiting the accumulation of Hg in plants, particularly reducing the concentration of THg (93%) and MeHg (85%) in water spinach. These results demonstrate that the interaction of organic and inorganic components can influence the biogeochemical behavior of soil Hg not only through their chemical properties, but also by altering the soil texture.

Distribution and Release of Mercury Regulated by the Decomposition of a Pioneer Habitat-Adapted Plant in the Water-Level-Fluctuating Zone of the Three Gorges Reservoir

Pioneer habitat-adapted bermudagrass is prevalent in the water-level-fluctuating zone of the Three Gorges Reservoir area. This study was performed to explore the response characteristics of dissolved organic matter (DOM) qualities to bermudagrass decomposition and their regulation in the distribution and release of mercury (Hg) and methylmercury (MeHg) in the soil-water system. Compared to the control, the bermudagrass decomposition resulted in a great increase in the protein-like components in the water in the initial stages (p < 0.01), but it also greatly reduced the humification degree of water DOM (p < 0.01). However, it accelerated the consumption of protein-like components, the humification rate, and the synthesis of humic-like DOM in the water over time. This changing pattern of the DOM qualities resulted in an initial elevation and a subsequent great decrease in the dissolved Hg and MeHg concentrations in the pore water, which ultimately reduced their release levels into the overlying water by 26.50% and 54.42%, respectively, compared to the control. Our results indicate the potential inhibitory effects of short-term bermudagrass decomposition caused by flooding and how decomposition affects the release of total Hg and MeHg by shaping the DOM qualities, and they have implications for similar aquatic systems in which herbaceous plants are frequently decomposed after submergence.

Mercury and methylmercury in Hg-contaminated paddy soil and their uptake in rice as regulated by DOM from different agricultural sources

In this study, from the perspectives of structural and compositional variations of soil-dissolved organic matter (DOM), we explored the effects of agricultural DOM inputs on methylmercury (MeHg) accumulation in the soil and mercury (Hg) bioaccumulation in rice grains. Pot experiments with the addition of DOMs from maize straw (MaS), rape straw (RaS), rice straw (RiS), composted rice straw (CRiS), cow dung (CD), and composted cow dung (CCD) were then conducted. Results showed that, relative to the control, the DOM amendment from each agricultural source elevated MeHg concentrations in the soil, with an increase of 18-227%, but only parts of DOMs elevated total dissolved Hg (DHg) and MeHg (DMeHg) concentrations in pore water. Among all DOM species, RiS, CRiS, and CCD significantly increased total Hg (THg) and MeHg contents in rice grains by 34-64% and 32-118%, respectively. Compared with RiS, THg and MeHg contents in rice grains in the CRiS treatment decreased slightly, which was consistent with the distributions of DHg and DMeHg concentrations in pore water and the aromaticity variation of soil DOM. In contrast, the CCD input significantly enhanced the enrichment of THg and MeHg in rice grains relative to CD because it significantly reduced the humification of soil DOM at all rice-growing stages while increasing the low-molecular-weight fractions in soil DOM. The THg and MeHg contents in the rice grains were significantly lower treated by RaS than those by MaS and RiS, which may be related to the higher sulfur-containing compounds such as sulfate and cysteine in rape straw or its DOM solution. Overall, DOM amendment from different agricultural sources resulted in significantly discriminative effects on the MeHg accumulation in soil and Hg enrichment in rice in the Hg-contaminated paddy field by shaping soil DOM properties.

Elevated methylmercury production in mercury-contaminated paddy soil resulted from the favorable dissolved organic matter variation created by algal decomposition

Algae-derived organic matter (AOM) may considerably regulate methylmercury (MeHg) production and accumulation in the paddy fields by changing the soil-dissolved OM (SDOM) properties. In this study, a 25-day microcosm experiment was performed to compare the responding mechanisms of MeHg production in the Hg-contaminated paddy soil-water system to the input of algae-, rice-, and rape-derived OMs. Results showed that algal decomposition could release much more cysteine and sulfate than crop straws. Compared with crop straw-derived OMs, AOM input greatly increased the dissolved organic carbon concentrations in soil but resulted in a greater decrease in tryptophan-like fractions while accelerated the formation of high-molecular-weight fractions in soil DOM. Moreover, AOM input significantly increased MeHg concentrations in the pore water by 19.43%-3427.66% and 52.81%-5846.57% compared to rape- and rice-derived OMs, respectively (P < 0.05). And, a similar MeHg changing pattern was also observed in the overlying water (10-25 d) and the soil solid-phase particles (15-25 d) (P < 0.05). Correlation analysis revealed that MeHg concentrations in the AOM-added soil-water system had significantly negative and positive relationships with the tryptophan-like C4 fraction and molecular weight (E2/E3 ratio) of soil DOM, respectively (P < 0.01). These findings suggest that AOM has a higher capacity than crop straw-derived OMs to promote MeHg production and accumulation in the Hg-contaminated paddy soils by creating a favorable soil DOM variation and providing more microbial electron donors and receptors.

Selenium/sulfur-modified montmorillonite materials mitigate mercury pollution in farmland

Selenium (Se) amendment could reduce mercury (Hg) bioaccumulation in crops, but sometimes it could cause excessive Se accumulation in crops and potential Se exposure risks for humans. In this study, we designed and synthesized selenium and sulfur-modified montmorillonite materials (Se/S-Mont) to effectively reduce mercury levels and avoid excessive Se enrichment in plants. The results of pot experiments (1 g Se/S-Mont/100 g soil) and field microplot trials (0.3 g Se/S-Mont/100 g soil, 8 t/ha) showed that Se/S-Mont amendments significantly reduced the Hg concentrations in water spinach and hybrid Pennisetum by 28-68% and 57%-92% (P < 0.05), respectively, while they did not lead to excessive Se bioaccumulation in the plants. Se/S-Mont was more efficient in mitigating soil Hg pollution than adding raw materials (e.g., NaSeO₃) and their combinations, and they significantly reduced the available Se fraction in the soil and the Se levels in the plants (P < 0.05). The potential mechanisms revealed by X-ray absorption near-edge spectra (XANES) and pot experiments were the adsorption and slow release of Hg, S, and Se by Se/S-Mont, the high affinity between Hg and Se, competition between Se and S, and the formation of stable complexes containing Se-S-Hg. The Se/S-Mont immobilizer was easy to prepare and required the application of small amounts, and the remediation effect was relatively stable and exhibited few negative effects; therefore, the approach showed high environmental and economic potentials.

Different dexamethasone doses in the perioperative period improve short-term outcomes of total hip arthroplasty: a randomized controlled trial

OBJECTIVE

This study aimed to evaluate the efficacy of different dexamethasone doses in the perioperative period of total hip arthroplasty (THA).

PATIENTS AND METHODS

We randomly divided 180 patients into three groups: three perioperative saline injections (Group A, placebo); two perioperative doses of 15 mg dexamethasone plus a postoperative saline injection at 48 h (Group B); and three perioperative doses of dexamethasone (10 mg) (Group C). Primary outcomes were postoperative pain at rest and while walking. We also recorded consumption of analgesics and antiemetics, incidence of postoperative nausea and vomiting (PONV), C-reactive protein (CRP) and interleukin-6 (IL-6) levels, postoperative length of stay (p-LOS), range of motion (ROM), nausea, Identity-Consequence-Fatigue-Scale (ICFS), and severe complications (e.g., incidence of surgical site infection, SSI and gastrointestinal bleeding, GIB).

RESULTS

Group B and C had significantly lower pain scores at rest than Group A on postoperative day 1. Group B and C also had significantly lower dynamic pain score, CRP, and IL-6 than Group A on postoperative day 1, 2, and 3. Patients in Group B and C had lower PONV incidence, reduced use of analgesics and antiemetics, improved ROM, shorter p-LOS, lower VAS nausea score, and lower ICFS than Group A patients. On postoperative day 3, patients in Group C had significantly lower dynamic pain and ICFS scores, IL-6, and CRP than Group B patients, as well as higher ROM. None of the groups exhibited SSI or GIB.

CONCLUSIONS

Dexamethasone provides short-term advantages in reducing pain, PONV, inflammation, and ICFS, and increasing ROM in the early postoperative period after THA. Dexamethasone efficacy in reducing post-THA pain, inflammation, and PONV at 10 mg and 15 mg is similar during the first 48 h. Dexamethasone (30 mg) divided into three 10 mg doses was superior to two doses (15 mg) in reducing pain, inflammation, and ICFS, as well as in increasing ROM on postoperative day 3.

The efficacy of aggressive warming combined with tranexamic acid during total hip arthroplasty: a single-center retrospective study from southern China

OBJECTIVE

The aim of the study was to evaluate the efficacy of aggressive warming combined with tranexamic acid (TXA) during total hip arthroplasty (THA).

PATIENTS AND METHODS

A total of 832 patients who underwent THA from October 2013 to June 2019 were divided into three groups according to the order of admission. There were 210 patients from October 2013 to March 2015 in group A, 302 patients from April 2015 to April 2017 in group B, and 320 patients from May 2017 to June 2019 in group C. Group A was the control group and was not given any measures. Group B was administered intravenously with 15 mg/kg TXA before skin incision and 3 h later without aggressive warming. Group C was administered intravenously with 15 mg/kg TXA before skin incision and 3 h later with aggressive warming. We evaluated the differences in the intraoperative blood loss, changes in core body temperature of patients at different stages during the operation, postoperative drainage, hidden blood loss, transfusion rate, drop of hemoglobin (Hb) on postoperative day 1 (POD1), prothrombin time (PT) of POD1, average hospitalization day, and complications.

RESULTS

There were statistically significant differences among the three groups during the intraoperative blood loss, intraoperative changes in core body temperature, postoperative drainage, hidden blood loss, blood transfusion rate, drop of Hb on POD1 and average hospital stay (p<0.05). There was no statistical difference in PT on POD1 and the incidence of complications (p>0.05).

CONCLUSIONS

Aggressive warming combined with TXA can significantly reduce the blood loss and transfusion rate of THA, and accelerate the recovery. We also observed that it does not increase the postoperative complications.

Effects of Composted Agricultural Organic Materials on Mercury Methylation in Paddy Soil and Mercury Enrichment in Rice

Many studies have shown that returning fresh straw to the field can promote mercury accumulation in crops; therefore, it is necessary to find an appropriate way to use agricultural organic materials in mercury-contaminated farmlands. In this study, pot experiments were conducted to study the effects of composted agricultural organic materials on mercury bioaccumulation in the paddy field ecosystem by adding fresh rice straw (RS), composted rice straw (CRS), cow dung (CD) and composted cow dung (CCD) to the soils. Compared with RS and CD, the CRS and CCD amendments reduced dissolved organic matter (DOM) contents in soil, but increased the aromaticity and small molecule proportion of DOM, and also increased the tartaric acid contents in soil, as well as the methylation and release of mercury in soil. However, the increased available mercury and methylmercury in the soils in the CRS and CCD treatments were not effectively absorbed by rice plants. Overall, compared with fresh organic materials, composted organic materials amendments could reduce mercury accumulation in rice to a certain extent.

[Characteristics and risk factors of spinal epidural hematoma after unilateral biportal endoscopic lumbar interbody fusion]

Objective: To investigate the incidence, characteristics and risk factors of spinal epidural hematoma after unilateral biportal endoscopic (UBE) lumbar spine surgery. Methods: The clinical data of 105 patients who underwent lumbar spine surgery under UBE in Guangdong Provincial People's Hospital from February 2020 to March 2021 were retrospectively reviewed. Of the patients, 48(45.7%) were male and 57(54.3%) were female, the mean age was (60.1±11.4) years (ranged 26 to 85 years). The MRI images at the third day post-surgery were observed, and the occurrence of hematoma was counted. Patients were assigned to normal group and hematoma group based on the presence of hematoma or not. The related clinical indicators of each patients were collected and used for comparison between two different groups. Logistic stepwise regression model was used to analyze whether each index was a risk factor for hematoma after the UBE lumbar fusion. Results: The total hematoma incidence rate was 28.6%(30/105), the symptomatic hematoma rate was 6.7%(7/105), and the hematoma reoperation rate was 0.9%(1/105). Univariate logistic regression analysis showed that hypertension (OR=3.368, 95%CI: 1.389-8.171), diabetes (OR=3.589, 95%CI: 1.230-10.476), admission systolic blood pressure>140 mmHg (1 mmHg=0.133 kPa,OR=3.687, 95%CI: 1.493-9.017), platelets<200×10⁹/L (OR=0.300, 95%CI: 0.119-0.785), preoperative blood calcium<2.25 mmol/L (OR=0.340, 95%CI: 0.142-0.818), spinal stenosis grade D (OR=4.462, 95%CI: 1.810-10.996) were possible risk factors for spinal hematoma after UBE lumbar fusion. Multivariate logistic regression analysis showed that admission blood pressure systolic blood pressure>140 mmHg (OR=3.788, 95%CI:1.055-13.606), preoperative blood calcium<2.25 mmol/L (OR=78.544, 95%CI:3.895-1 584.058) and spinal stenosis grade D (OR=3.698, 95%CI:1.110-12.325) were risk factors for spinal hematoma after UBE lumbar fusion (all P<0.05). Conclusion: The types of spinal canal hematoma after UBE lumbar fusion include localized and extended type. The risk factors for hematoma include high systolic blood pressure on admission, low preoperative blood calcium and severe spinal stenosis.

Remediation of Mercury-Polluted Farmland Soils: A Review

Mercury (Hg) bioaccumulation in Hg-polluted farmlands poses high health risk for humans and wildlife, and remediation work is urgently needed. Here, we first summarize some specific findings related to the environmental process of Hg in Hg-polluted farmlands, and distinguish the main achievements and deficiencies of available remediation strategies in recent studies. Results demonstrate that farmland is a sensitive area with vibrant Hg biogeochemistry. Current remediation methods are relatively hysteretic whether in mechanism understanding or field application, and deficient for large-scale Hg-polluted farmlands in view of safety, efficiency, sustainability, and cost-effectiveness. New perspectives including environment-friendly functional materials, assisted phytoremediation and agronomic regulations are worthy of further study as their key roles in reducing Hg exposure risk and protecting agricultural sustainability.

Effects of fulvic acid and humic acid from different sources on Hg methylation in soil and accumulation in rice

Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury (Hg) in paddy fields are still unclear. Here, fulvic acid (FA) and humic acid (HA) extracted from composted straw (CS), composted cow dung (CCD), peat soil (PM) and lignite coal (LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters (e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of MeHg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg (IHg) by 52.65% and 66.06% and of MeHg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of MeHg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.

Distribution of Mercury and Methylmercury in Farmland Soils Affected by Manganese Mining and Smelting Activities

Manganese (Mn)-related activities would affect the mercury (Hg) cycling in farmlands, whereas this was not well understood. Here, one of the largest Mn ores in China was selected to study the effects of Mn-related activities on the accumulation and distribution of total Hg (THg) and methylmercury (MeHg) in farmland soils. The soil THg concentrations in the mining area were 0.56 ± 0.45, 0.56 ± 0.45, 0.53 ± 0.44, and 0.50 ± 0.46 mg kg−1 in the 0−10, 10−20, 20−30, and 30−40 cm layers, respectively, while they were increased to 0.75 ± 0.75, 0.72 ± 0.60, 0.62 ± 0.46, and 0.52 ± 0.38 mg kg−1 in the smelting area. Similarly, the soil MeHg concentrations in the smelting area were also elevated by 1.04−1.34 times as compared to those in the mining area. Concentrations of THg (0.59 ± 0.50 mg kg−1) and MeHg (0.64 ± 0.82 μg kg−1) in soils were higher than the regional background value but lower than in vicinal Hg-mining areas, while they were largely elevated at the intersection of two rivers in the smelting area. Significant positive Mn-THg relationship (p < 0.01) and negative Mn-MeHg relationship (p < 0.01) favored the conclusion that soil Mn could promote Hg accumulation while inhibiting MeHg production. Approximately 70% of soil Hg was distributed in the residual phase, and the environmental hazard was not elevated according to a geochemical model. Overall, mining and smelting activities of Mn ores have resulted in obvious and distinct effects on the accumulation and methylation of Hg in farmland soils, but the environmental hazards are currently manageable.

[IRE1α deficiency impairs autophagy in chondrocytes by upregulating calcium homeostasis endoplasmic reticulum protein]

OBJECTIVE

To explore the mechanism by which inositol-requiring enzyme-1α (IRE1α) regulates autophagy function of chondrocytes through calcium homeostasis endoplasmic reticulum protein (CHERP).

METHODS

Cultured human chondrocytes (C28/I2 cells) were treated with tunicamycin, 4μ8c, rapamycin, or both 4μ8c and rapamycin, and the expressions of endoplasmic reticulum (ER) stress- and autophagy-related proteins were detected with Western blotting. Primary chondrocytes from ERN1 knockout (ERN1 CKO) mice and wild-type mice were examined for ATG5 and ATG7 mRNA expressions, IRE1α and p-IRE1α protein expressions, and intracellular calcium ion content using qPCR, Western blotting and flow cytometry. The effect of bafilomycin A1 treatment on LC3 Ⅱ/LC3 Ⅰ ratio in the isolated chondrocytes was assessed with Western blotting. Changes in autophagic flux of the chondrocytes in response to rapamycin treatment were detected using autophagy dual fluorescent virus. The changes in autophagy level in C28/I2 cells overexpressing CHERP and IRE1α were detected using immunofluorescence assay.

RESULTS

Tunicamycin treatment significantly up-regulated ER stress-related proteins and LC3 Ⅱ/LC3 Ⅰ ratio and down-regulated the expression of p62 in C28/I2 cells (P < 0.05). Rapamycin obviously up-regulated LC3 Ⅱ/LC3 Ⅰ ratio (P < 0.001) in C28/I2 cells, but this effect was significantly attenuated by co-treatment with 4μ8c (P < 0.05). Compared with the cells from the wild-type mice, the primary chondrocytes from ERN1 knockout mice showed significantly down-regulated mRNA levels of ERN1 (P < 0.01), ATG5 (P < 0.001) and ATG7 (P < 0.001), lowered or even lost expressions of IRE1α and p-IRE1α proteins (PP < 0.01), and increased expression of CHERP (P < 0.05) and intracellular calcium ion content (P < 0.001). Bafilomycin A1 treatment obviously increased LC3 Ⅱ/ LC3 Ⅰ ratio in the chondrocytes from both wild-type and ERN1 knockout mice (P < 0.01 or 0.05), but the increment was more obvious in the wild-type chondrocytes (P < 0.05). Treatment with autophagy dual-fluorescence virus resulted in a significantly greater fluorescence intensity of LC3-GFP in rapamycin-treated ERN1 CKO chondrocytes than in wild-type chondrocytes (P < 0.05). In C28/I2 cells, overexpression of CHERP obviously decreased the fluorescence intensity of LC3, and overexpression of IRE1α enhanced the fluorescence intensity and partially rescued the fluorescence reduction of LC3 caused by CHERP.

CONCLUSION

IRE1α deficiency impairs autophagy in chondrocytes by upregulating CHERP and increasing intracellular calcium ion content.

[Benefits and risks of prolonged dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stent in patients with stable coronary artery disease and diabetes]

Objective: To compare the efficacy and safety of prolonged dual antiplatelet therapy (DAPT>1 year) in patients with stable coronary artery disease (CAD) and diabetes who were event-free at 1 year after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) in a large and contemporary PCI registry. Methods: A total of 1 661 eligible patients were selected from the Fuwai PCI Registry, of which 1 193 received DAPT>1 year and 468 received DAPT ≤1 year. The primary endpoint was major adverse cardiac and cerebrovascular event (MACCE) and Bleeding Academic Research Consortium (BARC) type 2, 3 or 5 bleeding, MACCE was defined as a composite of all-cause death, myocardial infarction or stroke. Multivariate Cox regression analysis and inverse probability of treatment weighting (IPTW) Cox regression analysis were performed. Results: After a median follow-up of 2.5 years, patients who received DAPT>1 year were associated with lower risks of MACCE (1.4% vs. 3.2%; hazard ratio (HR) 0.412, 95% confidence interval (CI) 0.205-0.827) compared with DAPT ≤1 year, which was primarily caused by the lower all-cause mortality (0.1% vs. 2.6%; HR 0.031, 95%CI 0.004-0.236). Risks of cardiac death (0.1% vs. 1.5%; HR 0.051, 95%CI 0.006-0.416) and definite/probable ST (0.3% vs. 1.1%; HR 0.218, 95%CI 0.052-0.917) were also lower in patients received DAPT>1 year than those received DAPT ≤ 1 year. No difference was found between the two groups in terms of BARC type 2, 3, or 5 bleeding (5.3% vs. 4.1%; HR 1.088, 95%CI 0.650-1.821). Conclusions: In patients with stable CAD and diabetes who were event-free at 1 year after PCI with DES, prolonged DAPT (>1 year) provides a substantial reduction in ischemic cardiovascular events, including MACCE, all-cause mortality, cardiac mortality, and definite/probable ST, without increasing the clinically relevant bleeding risk compared with ≤ 1-year DAPT. Further well-designed, large-scale randomized trials are needed to verify the beneficial effect of prolonged DAPT in this population.

Effects of exogenous α-(1,4)-amylase on the utilisation of corn starch and glucose metabolism in broiler chickens

Starch is the most important energy source in corn-based diets for broiler chickens, however, some proportion of dietary starch may be partially digested, leading to a decrease in feed utilisation. Therefore, supplementing exogenous amylase might be a feasible way to improve the utilisation of dietary starch for poultry. This study investigated the effects of exogenous α-(1,4)-amylase supplementation on the utilisation of corn starch and glucose metabolism in broiler chickens. A total of 560, 4-d-old Arbour Acres plus male broiler chicks were randomly divided into five treatment groups and fed a corn-soybean meal diet supplemented with 0, 400, 600, 800 and 1 200 U/kg α-(1,4)-amylase to evaluate growth. The growth performance, nutrient digestibility coefficients, digestive enzyme activity, glucose transporter transcription and cecal microbiota composition were evaluated in this study. Starch digestibility coefficient showed a quadratic response to α-(1,4)-amylase at 14 d and 42 d (P < 0.05). However, the endogenous α-amylase activity in jejunal content was linearly decreased (P = 0.045). Also, exogenous α-(1,4)-amylase linearly decreased ileal Na+-dependent glucose and galactose transporter 1 mRNA expression at 42 d (P < 0.001). Exogenous α-(1,4)-amylase generated higher insulin and glucagon serum concentrations in fasted birds (P < 0.05) and following re-feeding for 2 h (P < 0.001). BW gain and feed intake were strongly positively correlated with starch digestibility coefficient at both 14 d (r = 0.87) and 42 d (r = 0.91); whereas, the relative weight of the gizzard was weakly negatively correlated with starch digestibility coefficient (r = -0.35). The relative abundance of Unclassified_Bacillaceae was moderately positively correlated (r > 0.50) while Oscillospira, Ornithobacterium and Unclassified_Barnesiellaceae were moderately negatively correlated (-0.50 < r -0.39) with starch digestibility coefficient. In conclusion, exogenous α-amylase modulates metabolic function by increasing insulin and glucagon concentrations, influenced gut microbiota which may impact starch digestibility in the jejunum and ileum. The results of this study showed that excessive addition of exogenous α-(1,4)-amylase was not beneficial for the utilisation of starch in broiler chickens. Supplement more than 600 U/kg α-(1,4)-amylase inhibited glucose transporters, decreases the coefficients of starch and organic matter digestibility in the small intestine to a varying degree, thereby limiting the growth performance of broiler chickens.

Fulvic acid: A key factor governing mercury bioavailability in a polluted plateau wetland

Fulvic acids (FAs) are known to regulate the fate of mercury (Hg) in sediments, but the key effects of their properties are still unclear. In this study, field investigations and simulation experiments were conducted in a heavy metal-polluted wetland to identify FA characteristics and their association with the production and bioaccumulation of methylmercury (MeHg). Compared to permanently inundated areas (PIA), seasonally inundated areas (SIAs) had lower total Hg levels in sediments, whereas higher MeHg levels in sediments (0.20 ± 0.09 ng g^-1 vs. 0.55 ± 0.31 ng g^-1) and benthos (0.25 ± 0.22 ng g^-1 vs. 1.62 ± 1.78 ng g^-1). Meanwhile, the THg and MeHg concentrations in the same macrophyte species between PIA and SIA also followed a similar rule with benthos. FA-bound Hg in the sediment was significantly correlated with MeHg in the sediment (p < 0.01), as well as THg and MeHg in benthos (p < 0.05), indicating that FAs have the capacity to promote MeHg production and bioaccumulation. Moreover, the FAs in the sediments of the SIA had lower fractions and alkyl C/O-alkyl C ratios, but higher molecular weights and THg/MeHg concentrations than those in the PIA, indicating that FAs in SIA have increased bioavailability and enhanced competition for Hg, favoring significantly elevated FA-bound Hg levels. Biological exposure testing further demonstrated that FAs extracted from SIA had a greater ability to increase the production and bioaccumulation of MeHg than those extracted from PIA. Overall, these results highlight that the molecular composition and sources of FAs, excluding their concentrations, are one of important factors responsible for the obvious spatial heterogeneity of MeHg in sediments and aquatic organisms in the wetland.

Implications of ESC-high tthrombotic risk features and ARC-high bleeding risk criteria on clinical outcomes in all-comer patients undergoing PCI

Background

High thrombotic risk (HTR) and high bleeding risk (HBR) features after PCI can occur in the same patient. The individualized risks of ischemic vs. bleeding events are needed to be considered for determining the optimal duration of DAPT. We aimed to evaluate long-term ischemic and bleeding outcomes in patients who are at both HTR and HBR after DES implantation.

Methods

All consecutive patients who underwent PCI with DES were prospectively enrolled in Fuwai PCI Registry. HTR criteria based on 2017 ESC DAPT guidelines were defined as: diffuse multivessel diabetic CAD patients, chronic kidney disease, ≥3 stents implanted, ≥3 stents lesions treated, bifurcation with two stents implanted, total stent length &gt;60 mm, or chronic total occlusion. Patients were defined as HBR if they met at least 1 major or 2 minor Academic Research Consortium (ARC)-HBR criteria. The primary ischemic outcome was major adverse cardiac event (MACE), a composite of cardiac death, myocardial infarction, target vessel revascularization and stent thrombosis.

Results

Among 10,167 patients, 4,430 (43.6%) qualified as HTR. The rate of HBR patients was significantly higher in the HTR group than in the non-HTR group (18.9% versus 12.2%, P&lt;0.001). Compared to those having non-HTR., Patients with ESC-HTR had higher 30-month rates of MACE (hazard ratio [HR] adjust: 1.56, 95% confidence interval [CI]: 1.34–1.82; P&lt;0.001), device-oriented composite endpoint (composite of cardiac death, target-vessel MI, and target lesion revascularization) (HRadjust: 1.52 [1.27–1.83]; P&lt;0.001), cardiac mortality, myocardial infarction, stent thrombosis, any revascularization, and stroke, without increasing the risk of BARC type 2, 3, or 5 bleeding. MACE rates at 30 months among those without HTR or HBR, HBR alone, HTR alone, and both HTR and HBR were 5.1%, 6.0%, 8.3%, and 8.8%, respectively (P&lt;0.001). Associations between HTR and adverse events were similar in HBR and no HBR groups, without evidence of interaction; however, adverse event rates were highest among subjects with both HBR and HTR.

Conclusions

A combination of ESC-HTR and ARC-HBR may increase the risk of long-term ischemic events, including cardiac mortality, emphasizing the importance of considering the net clinical benefit including high ischemic and bleeding features. Our data suggest that ESC-HTR criteria was useful for stratifying post-PCI patients into risk strata for future ischemic events.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Beijing Municipal Health Commission (Grant No. 2020-1-4032) Kaplan-Meier event rates

Xinnaokang improves cecal microbiota and lipid metabolism to target atherosclerosis

This study aims to explore the potential mechanisms of Xinnaokang in atherosclerosis treatment. Firstly, the active components of Xinnaokang were analysed by HPLC, which contains ginsenoside Rg1, puerarin, tanshinone, notoginsenoside R1, ammonium glycyrrhizate and glycyrrhizin. Network pharmacology analysis showed there were 145 common targets of Xinnaokang, including the chemical stress, lipid metabolite, lipopolysaccharide, molecules of bacterial origin, nuclear receptor and fluid shear stress pathways. Then, the animal experiment showed that Xinnaokang reduced the body weight and blood lipid levels of atherosclerotic mice. Vascular plaque formation was increased in atherosclerotic mice, which was markedly reversed by Xinnaokang. In addition, Xinnaokang reduced CAV-1 expression and increased ABCA1, SREBP-1 and LXR expressions in the vasculature. Xinnaokang promoted SREBP-2 and LDLR expressions in the liver but decreased IDOL and PCSK9 expressions, indicating that Xinnaokang regulated lipid transport-related protein expression. Cecal microbiota diversity was reduced in atherosclerotic mice but increased after Xinnaokang treatment. Xinnaokang treatment also improved gut microbiota communities by enriching Actinobacteria, Bifidobacteriales and Bifidobacteriaceae abundances. Metabolic profile showed that Xinnaokang significantly reduced homogentisate, phenylacetylglycine, alanine and methionine expressions in the liver of atherosclerotic mice. Xinnaokang effectively alleviated atherosclerosis, and this effect might be linked with the altered features of the liver metabolite profiles and cecal microbiota.

Optimal strategy for antiplatelet therapy after coronary drug-eluting stent implantation in high-risk "TWILIGHT-like" patients with diabetes mellitus

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Chinese College of Cardiovascular Physicians, CS Optimizing Antithrombotic Research Fund (Grant No. BJUHFCSOARF201801-01), the National Key Research and Development Program of China (Grant No. 2018YFC1315602), the Beijing Municipal Health Commission (Grant No. 2020-1-4032), the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (Grant No. 2016-I2M-1-009), and the National Natural Science Foundation of China (Grant No. 81870277).

Background

Patients with diabetes mellitus (DM) are known to be at high-risk for both ischemic and bleeding complications post-percutaneous coronary intervention (PCI). The ischemic benefit versus bleeding risk associated with extended dual antiplatelet therapy (DAPT) in high-risk "TWILIGHT-like" patients with diabetes mellitus after PCI has not been established.

Methods

All consecutive high-risk patients fulfilling the "TWILIGHT-like" criteria undergoing PCI from January 2013 through December 2013 were identified from prospective Fuwai PCI Registry. High-risk "TWILIGHT-like" patients were defined by at least 1 clinical and 1 angiographic feature based on TWILIGHT trial selection criteria. The present analysis evaluated 3425 diabetics patients with concomitant high-risk angiographic features who were event-free at 1 year after PCI. Median follow-up was 2.4 years. The primary effectiveness endpoint was a composite of death, myocardial infarction, or stroke (termed major adverse cardiac and cerebrovascular events) and primary safety endpoint was clinically relevant bleeding according to Bleeding Academic Research Consortium type 2, 3, or 5.

Results

On inverse probability of treatment weighting (IPTW) analysis, prolonged-term (&gt;1-year) DAPT with aspirin and clopidogrel decreased the risk of primary effectiveness endpoint compared with shorter (≤1-year) DAPT (1.8% vs. 4.3%; hazard ratio [HR]IPTW: 0.381; 95% confidence interval [CI]: 0.252-0.576; P &lt; 0.001) and reduced cardiovascular death (0.1% vs. 1.8%; HRIPTW: 0.056 [0.016-0.193]). Prolonged DAPT was also associated with a reduced risk of definite/probable stent thrombosis (0.2% vs. 0.7%; HRIPTW: 0.258 [0.083-0.802]), and non-significantly lower rate of myocardial infarction (0.5% vs. 0.8%; HRIPTW: 0.676 [0.275-1.661]). There was no significant difference between groups in clinically relevant bleeding (1.1% vs. 1.1%; HRIPTW: 1.078 [0.519-2.241]; P = 0.840). Similar results were observed in multivariable Cox proportional hazards regression model.

Conclusion

Among high-risk PCI patients with diabetes mellitus without an adverse event through 1 year, extending DAPT &gt; 1-year significantly reduced the risk of major adverse cardiac and cerebrovascular events without an increase in clinically relevant bleeding, suggesting that such high-risk diabetic patients may be good candidates for long-term DAPT.

Abstract Figure.

Impact of ESC-endorsed high ischemic risk features and ARC-high bleeding risk criteria on clinical outcomes in all-comer patients undergoing PCI

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Beijing Municipal Health Commission (Grant number: 2020-1-4032).

Background

Whether the underlying risk of high bleeding risk (HBR) influences the relationship of high ischemic risk (HIR) features with adverse events after drug-eluting stent implantation remains unclear. The purpose of this study was to evaluate (1) the prognostic effect of ESC guideline-endorsed HIR features on long-term clinical outcomes and (2) whether the outcomes of HIR versus non-HIR features vary by HBR status.

Methods

Ten thousand one hundred sixty-seven consecutive patients who underwent percutaneous coronary intervention between January 2013 and December 2013 were prospectively enrolled in Fuwai PCI Registry. Patients who are at HIR were defined as: diffuse multivessel disease in diabetic patients, chronic kidney disease, at least three stents implanted, at least three stents lesions treated, bifurcation with two stents implanted, total stent length &gt; 60 mm, or treatment of chronic total occlusion. The definition of HBR was based on the Academic Research Consortium (ARC) for HBR criteria. The primary ischemic outcome was major adverse cardiac event (MACE), a composite of cardiac death, myocardial infarction, target vessel revascularization and stent thrombosis. The primary bleeding outcome was clinically relevant bleeding, defined according to Bleeding Academic Research Consortium (BARC) type 2, 3 or 5 bleeding.

Results

With a 2.4-year median follow-up, 4430 patients (43.6%) having HIR experienced a significantly higher risk of MACE (hazard ratio [HR] adjust : 1.56, 95% confidence interval [CI]: 1.34–1.82; P &lt; 0.001) and device-oriented composite endpoint (composite of cardiac death, target-vessel MI, and target lesion revascularization) (HRadjust : 1.52 [1.27–1.83]; P &lt; 0.001), compared to those having non-HIR. The risk of clinically relevant bleeding did not differ between groups (HRadjust : 0.85 [0.66–1.08]; P = 0.174). Associations between HIR and adverse events were similar in HBR and non-HBR groups, without evidence of interaction (all P interaction &gt; 0.05); however, adverse event rates were highest among subjects with both HIR and HBR.

Conclusions

ESC guideline-endorsed HIR was associated with significantly increased risk of MACE without any significant differences in clinically relevant bleeding. The presence of ARC-HBR does not emerge as a modifier of cardiovascular risk for patients at HIR, suggesting more potent and longer antiplatelet therapy may be beneficial for this patient population.

Long-term ischemic and bleeding risk with extended dual antiplatelet therapy after PCI in patients with 2018 ESC/EACTS myocardial revascularization guideline-endorsed high thrombotic risk features

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Beijing Municipal Health Commission (Grant number: 2020–1-4032)

Background

The ischemic/bleeding trade-off of continuing dual antiplatelet therapy (DAPT) beyond 1 year after PCI for patients with high thrombotic risk (HTR) as endorsed by 2018 ESC/EACTS myocardial revascularization guidelines remain unknown. We sought to evaluate the benefits and harms of DAPT with aspirin and clopidogrel beyond 1 year versus ≤ 1-year DAPT on long-term clinical outcomes after PCI with DES among ESC/EACTS guideline-endorsed HTR patients that are event-free at 1 year follow-up, using a prospective, real-world registry.

Methods

Patients undergoing coronary stenting between January 2013 and December 2013 from the prospective Fuwai registry were defined as HTR if they met at least 1 ESC/EACTS guideline-endorsed HTR criteria with at least 1 of the following characteristics: diffuse (lesion length ≥ 20 mm) multivessel disease in diabetic patients, CKD (estimated glomerular filtration rate &lt; 60 mL/min), ≥ 3 stents implanted, ≥ 3 lesions treated, bifurcation with 2 stents implanted, total stent length &gt; 60 mm, treatment of CTO, and history of STEMI. A total of 4578 patients who were at HTR and were events free at 1 year after the index procedure were evaluated. The primary efficacy outcome was major adverse cardiac and cerebrovascular events (MACCE) (composite of all-cause death, myocardial infarction, or stroke).

Results

Median follow-up period was 2.4 years. &gt; 1-year DAPT with clopidogrel and aspirin significantly reduced the risk of MACCE compared with ≤ 1-year DAPT (1.9% vs. 4.6%; hazard ratio (HR): 0.38; 95% confidence interval (CI): 0.27–0.54; P &lt; 0.001), driven by a reduction in all-cause death (0.2% vs. 3.0%; HR, 0.07; 95% CI, 0.03–0.15). Cardiac death and definite/ probable stent thrombosis also occurred less frequently in prolonged DAPT group. Bleeding Academic Research Consortium (BARC) type 2, 3, or 5 bleeding occurred similarly between both groups (1.1% vs. 0.9%; HR, 1.11; 95% CI, 0.58–2.13; P = 0.763). Similar results were found using multivariable Cox model, propensity score-matched, and inverse probability of treatment weighting analysis.

Conclusions

Among patients with ESC-endorsed HTR who were free from major ischemic or bleeding events 1 year after coronary stenting, continued DAPT beyond 1 year might offer better effectiveness in terms of atherothrombotic events and comparable safety in terms of clinically relevant bleeding compared with ≤ 1-year DAPT. ESC-HTR criteria is an important parameter to take into account in tailoring DAPT prolongation.

Parsing the microRNA genetics basis regulating skeletal muscle fiber types and meat quality traits in pigs

Muscle fibers are closely related to human diseases and livestock meat quality. However, the genetics basis of microRNAs (miRNAs) in regulating muscle fibers is not completely understood. In this study, we constructed the whole genome-wide miRNA expression profiles of porcine fast-twitch muscle [biceps femoris (Bf)] and slow-twitch muscle [soleus (Sol)], and identified hundreds of miRNAs, including four skeletal muscle-highly expressed miRNAs, ssc-miR-378, ssc-let-7f, ssc-miR-26a, and ssc-miR-27b-3p. Moreover, we identified 63 differentially expressed (DE) miRNAs between biceps femoris vs. soleus, which are the key candidate miRNAs regulating the skeletal muscle fiber types. In addition, we found that the expression of DE ssc-miR-499-5p was significantly correlated to the expression of Myoglobin (r = 0.6872, P < 0.0001) and Myosin heavy chain 7 (MYH7; r = 0.5408, P = 0.0020), and pH_45 min (r = 0.3806, P = 0.0380) and glucose content (r = -0.4382, P = 0.0154); while the expression of DE ssc-miR-499-3p was significantly correlated to the expression of Myoglobin (r = 0.5340, P = 0.0024) and pH_45 min (r = 0.4857, P = 0.0065). Taken together, our data established a sound foundation for further studies on the regulatory mechanisms of miRNAs in skeletal muscle fiber conversion and meat quality traits in livestock, and could provide a genetic explanation of the role of miRNAs in human muscular diseases.

Mercury Bioaccumulation in Freshwater Snails as Influenced by Soil Composition

Soil properties largely control the fate of mercury (Hg), including the synthesis of neurovirulent methylmercury (MeHg). Here, the freshwater snail (Cipangopaludina cahayensis), a snail species commonly bred in flooded farmland, was used in a test of biotoxicity exposure to explore the effects of soil components on Hg bioavailability. The results show that snails incubated on the surface of slightly Hg-polluted flooded soil (2.0 mg/kg) have MeHg concentrations of 7.9 ± 1.5 mg/kg, which greatly exceed the limit of contaminants in food in China (0.5 mg/kg). The addition of ferrous disulfide can significantly increase the MeHg concentrations in soils while reducing the concentrations of total Hg (THg) and MeHg levels in snails by 59.1% and 64.3%, respectively. Peat-derived fulvic acid has the capacity to reduce the MeHg concentrations in soils and snails by 23.8% and 33.2%, respectively, whereas it increases the dissolved Hg levels in overlying water by 104.3%. Moreover, Fe-Mn oxides and humic acid can consistently reduce THg and MeHg concentrations in snails. Overall, freshwater snails bred in Hg-polluted areas may suffer from a high risk of Hg exposure, and importantly, some soil components such as ferrous disulfide and humic acid have strong inhibitory effects on Hg bioaccumulation in snails.

Ecological risks of heavy metals as influenced by water-level fluctuations in a polluted plateau wetland, southwest China

The Caohai wetland, one of karst plateau wetlands in southwest China, is given more attention due to the serious heavy metal (HM) pollution from artisanal zinc smelting activities. A natural hydrological change has caused this wetland to form a water-level fluctuating zone. This raises a question of whether such an area has elevated HM risks to the aquatic environment, and it was explored by a field investigation and biological exposure experiment. The results showed that Caohai sediment properties were significantly altered by water-level fluctuation, and the permanently inundated sediment had obviously higher organic matter (SOM) concentrations (32.62 ± 9.37%), humification levels (ratio of C to H, 6.81 ± 0.97), and Fe oxide fractions (12.29 ± 3.17%) than seasonally inundated sediment (4.94 ± 2.25%, 1.33 ± 0.75, and 8.72 ± 1.87%, respectively). These significantly enhanced the competition and retention, resulting in the increased accumulation, whereas reduced bioavailability of HMs. In comparison, the mean bioaccumulation capacity of Zn, Pb and Cd by wild benthos at the seasonally inundated area respectively increased by 2, 11 and 20 times higher than that at the permanently inundated area, which was further verified in the biological incubation experiment. Our results suggest that hydraulic fluctuation can greatly shape the sediment properties to increase the ecological risks of HMs to organisms.

Modified clay mineral: A method for the remediation of the mercury-polluted paddy soil

Rice is easy to accumulate mercury (Hg), especially methylmercury (MeHg) with high toxicity, and this leads to a serious health risk for residents in some Hg-polluted areas of Asia. Thus, there is an urgent need to find soil remediation techniques that can both guarantee agricultural production and protect human health in these Hg-contaminated areas. In this study, montmorillonite (Mont) and medical stone (Med) were modified by a thiol-based material (-SH) and by chitosan to obtain modified clay mineral adsorbents. Pot experiments were then performed to explore their ability to reduce the levels of Hg and MeHg in rice and their reduction mechanisms. Compared with unmodified clay minerals, modified clay minerals had better Hg reduction efficiencies in rice. The amendment of SH-modified Med (Med-SH) had the highest THg and MeHg reduction efficiencies in rice, reaching up to 78% and 81%, respectively, and brought the THg concentration in the rice below China's health guidelines for rice (20 ng g^-1). Not only did amendment of the SH-modified clay minerals reduce the exchangeable and specially adsorbed Hg in the soil, as did the other amendments, but they also significantly reduced the amount of oxide-bound Hg and MeHg in the soil, and greatly enhanced the retention of Hg and MeHg in soil, thus significantly reduced the concentration of Hg and MeHg in rice.

Efficacy of laparoscopic gastric bypass vs laparoscopic sleeve gastrectomy in treating obesity combined with type-2 diabetes

OBJECTIVE

This prospective study compared the efficacy and safety of laparoscopic gastric bypass and laparoscopic sleeve gastrectomy in treating overweight and obese patients with BMI>28 kg/m² and type-2 diabetes.

METHODS

Patients were randomized into a gastric bypass group (n = 77) or a gastrectomy group (n = 80). The surgery time, intraoperative blood loss, recovery time, and hospitalization time were collected. BMI, waistline, hipline, C-peptide level, insulin resistance index (HOMA-IR), and their blood and lipid profile were also measured.

RESULTS

Surgery time and blood loss were significantly higher in the gastrectomy group, when compared to the gastric bypass group (P < 0.05). In both groups, the levels of BMI, waist circumference and hip circumference (but not their ratio) gradually and significantly decreased after surgery compared with baseline (P < 0.05), and no significant difference was found between these two groups. The C-peptide level, HOMA-IR, fasting blood glucose, 2-hour postprandial blood glucose and glycosylated haemoglobin gradually and significantly decreased after surgery compared with the values before treatment (P < 0.05). The levels of total cholesterol, triglyceride, LDL, and monocyte chemoattractant protein-1 were also lower after surgery in both groups, while HDL and glucagon-like peptide-1 were significantly higher after surgery compared with the values before treatment (P < 0.05). However, no significant difference was found between these two groups of patients.

CONCLUSION

Both laparoscopic gastric bypass and laparoscopic sleeve gastrectomy improved the BMI and diabetic conditions of overweight/obese diabetics, while laparoscopic sleeve gastrectomy had a shorter surgical time and less blood loss.

An integration analysis based on genomic, transcriptomic and QTX information reveals credible candidate genes for fat-related traits in pigs

Meat quality improvement is of great interest to researchers in pig breeding and many researchers have identified abundant associated quantitative trait loci, genes and polymorphisms (QTXs) for fat-related traits. However, it is challenging to determine credible candidate genes from a mass of associations. The efficiency of identification of credible candidate genes in these QTXs is restricted by limited integration analyses of data from multiple omics. In this study, we constructed a 'candidate gene map' of fat-related traits in pigs based on published literature and the latest genome. In total, 6,861 QTXs, which covered 9,323 genes on the pig genome, were used. Combining the QTX hotspots and pathway analysis, we identified 180 candidate genes that may regulate the fat-related traits, and choose PNPLA2, PPARG, SREBF1, ACACA, PPARD and PPARA as credible candidate genes. In addition, we discussed the importance of incorporating transcriptome data and genomic data in causal gene identification, and the multi-omics information can effectively improve the credibility of identified candidate genes.

THU0408 EFFECT OF NEW-ONSET GOUT ON KIDNEY TRANSPLANT OUTCOMES: A RETROSPECTIVE COHORT ANALYSIS OF THE UNITED STATES RENAL DATA SYSTEM

Background:

Gout is a frequent comorbidity in kidney transplant (KT) recipients. However, assessing the independent effect of gout on KT outcomes is difficult because of multiple confounders (e.g., temporal changes in estimated glomerular filtration rate [eGFR], cyclosporine or tacrolimus dose, urate-lowering medication use) that obscure a clear picture of gout’s potential impact.

Objectives:

This investigation assessed if the development of new-onset gout after KT was an independent risk factor for loss of graft function, as assessed by the need for maintenance hemodialysis following KT.

Methods:

This retrospective cohort study analyzed data on patients in the United States Renal Data System (USRDS) who received a primary KT between 1/1/2008 and 12/31/2015. The date of transplantation was the ‘index’ date. Eligible patients were required to have ≥24 months of Medicare coverage and no prior history of gout, defined as ≥1 claim with a gout diagnosis code in the 24 months prior to the index date. All patients were also required to have ≥12 months of coverage post index. Patients who died, experienced graft failure, or returned to dialysis <12 months post index were excluded. Because the first year following transplant is associated with the highest frequency of rejections, we evaluated subjects beginning 1 year after transplant. The exposure of interest was new-onset gout, defined as the presence of ≥2 claims for gout post index, and the primary endpoint was return to dialysis >12 months post index. Baseline time-invariant confounders included recipient and donor demographics and clinical characteristics at index. Time-varying confounders included body mass index (BMI) adjusted tacrolimus and cyclosporine dose, eGFR, and urate-lowering medication use post index. Patients who died or lost Medicare coverage >12 months post index were censored; all patients remaining at the end of the study period (12/31/2016) were also censored. A marginal structural model (MSM) was fitted to determine the relative risk of new-onset gout on return to dialysis, while controlling for both time-invariant and time-varying confounders.

Results:

18,525 of 466,589 KT recipients in the USRDS met study eligibility. Within the observation period, 1,399 (7.6%) developed new-onset gout and 1,420 (7.7%) returned to dialysis >12 months post index. Median time from index to new-onset gout and from index to return to dialysis was 16.2 months (IQR: 33.4) and 32.8 months (IQR: 28.4), respectively. Adjusting for baseline time-invariant and time-varying confounders via the MSM showed new-onset gout was associated with a 51% increased risk of return to dialysis >12 months post index (RR: 1.51, 95% CI: 1.03, 2.20).

Conclusion:

New-onset gout was independently associated with a 51% increased risk of return to dialysis >12 months after primary KT compared to a control cohort without gout. To our knowledge, this is the first observation of this outcome in an appropriately controlled cohort study of KT recipients with gout. Results from this analysis may have important implications for the monitoring and management of new-onset gout in the kidney transplant population.

References:

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Disclosure of Interests: :

Justin Li: None declared, David Yin: None declared, Zheng Wang: None declared, Mark Brigham: None declared, Brian LaMoreaux Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Jeffrey Kent Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Megan Francis-Sedlak Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Richard Johnson Shareholder of: Colorado Research Partners LLC, XORTX Therapeutics, Consultant of: Horizon Therapeutics, Eli Lilly, Speakers bureau: Horizon Therapeutics, Nandini Hadker: None declared, Kevin Francis: None declared, Herman Sanchez: None declared, Gavin Miyasato: None declared

Linking vein properties to leaf biomechanics across 58 woody species from a subtropical forest

Leaf venations have elements with relatively lower elasticity than other leaf tissue components, which are thought to contribute to leaf biomechanics. A better mechanistic understanding of relationships between vein traits and leaf mechanical properties is essential for ecologically relevant interpretation of leaf structural variations. We investigated 13 major (first to third order) and minor (>third order) vein traits, six leaf mechanical properties and other structural traits across 58 woody species from a subtropical forest to elucidate how vein traits contribute to leaf biomechanics. Across species, vein dry mass density (ρ_v ), total vein dry mass per leaf area (VMA) and minor vein diameter (VD_min ), but not the lower-order vein density (VLA_1•2 ), were positively correlated with leaf force to punch (F_p ) and force to tear (F_t ). Structural equation models showed that ρ_v and VD_min not only contribute to leaf mechanical properties directly (direct pathway), but also had impacts on leaf biomechanics by influencing leaf thickness and leaf dry mass per area (indirect pathway). Our study demonstrated that vein dry mass density and minor vein diameter are the key vein properties for leaf biomechanics. We also suggest that the mechanical characteristics of venations are potential factors influencing leaf mechanical resistance, structure and leaf economics spectrum.

Production and migration of methylmercury in water-level-fluctuating zone of the Three Gorges Reservoir, China: Dual roles of flooding-tolerant perennial herb

Water-level-fluctuating zone (WLFZ) is a prevalent water-land ecotone favorable for mercury (Hg) methylation. The succession of flooding tolerance plants in WLFZ gradually changes the landscape, and also brings a new question worth understanding whether these plants would enhance methylmercury (MeHg) production in WLFZ and increase risks to the aquatic environment. Given bermudagrass (Cynodon dactylon (L). Pers) as the dominant perennial herb with high flooding-tolerance in WLFZ of the Three Gorges Reservoir (TGR), we conducted a comprehensive study to investigate its roles in the production and migration of MeHg in WLFZ by field observations and stable isotope tracer experiments. Results showed that both elevated MeHg levels and Hg methylation rates appeared in soil/sediment in bermudagrass growing area, implying that the growth of bermudagrass could significantly enhance MeHg production. However, MeHg migration from sediment to water was restricted during the flooding period of the TGR, as obviously higher partitioning coefficients of MeHg between the sediment and porewater (p <  0.05) and lower MeHg release fluxes were observed in vegetated area, indicating that the presence of bermudagrass instead probably decreased the water MeHg level. Whereas, it is noteworthy that elevated MeHg in soil/sediment induced by the bermudagrass could pose potential risks to the benthos and further to the TGR food chain.

A Review of Studies on the Biogeochemical Behaviors of Mercury in the Three Gorges Reservoir, China

The Three Gorges Reservoir (TGR) is a relatively large reservoir, and its water level management actions produce a widespread water level fluctuation zone (WLFZ), which has characteristics of both terrestrial and aquatic ecosystems. Here, an integrated overview of current knowledge on Hg behaviors in the TGR, especially the WLFZ, as well as exposure risk to local residents was presented. Hg levels in the TGR were comparable with other natural aquatic systems. WLFZ in the TGR was confirmed to be an environment favorable for Hg methylation by enhancing microbial activity, promoting sulfur cycling and increasing the level of low-molecular-weight organic matters. However, elevated fish Hg concentrations did not follow the impoundment of TGR, indicating no obvious reservoir effect, while it is still noteworthy that frequently consuming fish is likely to be a methylmercury (MeHg) exposure pathway for specific populations e.g. fishermen around the TGR.

Distribution of clinically relevant antibiotic resistance genes in Lake Tai, China

Lake Tai is China's third largest freshwater lake and an important water resource for agriculture, industrial sectors, and as drinking water for several large cities. In this study, the occurrence of five antibiotic resistance genes (sul1, bla_TEM, bla_NDM-1, bla_CTX-M-32, mcr-1) was investigated in water and sediment samples collected from Lake Tai. Antibiotic resistances are currently increasing, posing a significant threat to public health. The sulfonamide resistance gene sul1 was highly abundant in all analyzed water and sediment samples. In addition, the two β-lactamase genes bla_TEMand bla_NDM-1 - encoding clinically relevant antibiotic resistances - were detected in 67.1 and 7.3% of the water samples and in 70.7 and 15.4% of the sediment samples. The third β-lactamase gene, bla_CTX-M-32, was only detected in water samples (13.4%), while the colistin resistance gene mcr-1 was not detected in any of the samples. No significant variations between different sampling sites or time points could be observed. The investigation of drinking water treatment at Lake Tai, using lake water as influent, showed a significant reduction of the antibiotic resistance genes through the treatment process. Microbial source tracking showed only low fecal contamination by humans, ruminants, and pigs, indicating the relevance of other sources such as fish farms. Overall, our results provide important insights into the occurrence and abundance of antibiotic resistance genes in the Lake Tai water system and their elimination via drinking water treatment.

Bioaccumulation characteristics of mercury in fish in the Three Gorges Reservoir, China

Newly constructed reservoirs were recognized as hotspot of mercury (Hg) methylation, and then methylmercury (MeHg) accumulation in food chains. The risk of elevated MeHg concentrations in fish is one of the most important concerns in newly constructed reservoirs. The Three Gorges Reservoir (TGR) is one of the largest reservoirs in the world. However, the distribution and bioaccumulation characteristics of Hg species within the food chains and its potential ecological risk in the TGR remain poorly understood. In this study, 264 fish individuals covering 18 species were collected from the TGR. Total mercury (THg) and MeHg concentrations in different organs (gill, heart, liver, muscle and swim bladder) of fish species were analyzed; the values of δ¹³C and δ¹⁵N in fish muscle were determined as well to reveal the biomagnification properties of Hg in food chains. Our results showed that concentrations of THg (0.5-272 ng g^-1, w.w.) and MeHg (0.1-199 ng g^-1, w.w.) in fish muscle from the TGR ubiquitously fall below the safe fish consumption limit on Hg recommended by WHO (500 ng g^-1, w.w.) and the US-EPA Water Quality Criterion for MeHg (300 ng g^-1, w.w.). The short food web jointly with the limited trophic magnification factor in the TGR explained the relatively low Hg concentrations in predators. Among the five fish organs, muscle represented the highest Hg concentrations, followed by heart, liver, swim bladder, and gill, suggesting that muscle has the highest ability to accumulate Hg compared to the other organs. More importantly, no discernible "reservoir effect" was observed in the TGR within the initial few years after impoundment due to its special eco-environment including: 1) neutral and slightly alkaline pH and low dissolved organic carbon of water, 2) less vegetation coverage in inundated areas, 3) simple food web.

Inorganic sulfur and mercury speciation in the water level fluctuation zone of the Three Gorges Reservoir, China: The role of inorganic reduced sulfur on mercury methylation

The water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China is a unique geomorphological unit that undergoes annual flooding and drying alternation cycle. The alternating redox conditions within the WLFZ are expected to result in dynamic cycling of reduced sulfur species, which could affect mercury (Hg) methylation due to the high affinity of reduced sulfur species to both inorganic divalent mercury (Hg(II)_i) and methylmercury (MeHg). Variations of inorganic sulfur species (measured as acid volatile sulfide, chromium reductive sulfur, elemental sulfur, and water-soluble sulfate), total mercury (THg) and MeHg were studied at two typical WLFZ sites in the TGR from July 2015 to June 2016. Whereas the water-soluble sulfate contents stayed essentially constant, the reduced inorganic sulfur contents varied greatly as the water level changed. Compared with the control soils, the MeHg contents in the WLFZ soils increased, suggesting that water level fluctuations accelerated the methylation process of Hg(II)_i. In situ Hg(II)_i-methylation also appeared to occur in the sub-layer of the drained sediment during the draw-down season. The significant correlation between MeHg and elemental sulfur (S(0)) further suggests that polysulfides may have played a role in Hg(II)_i-methylation by increasing the bioavailable Hg(II)_i content in the WLFZ of the TGR.

Effects of soil properties on production and bioaccumulation of methylmercury in rice paddies at a mercury mining area, China

Rice paddy soil is recognized as the hotspot of mercury (Hg) methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury (MeHg) in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites (a total of 124 paddy fields) in the Wanshan Mercury Mine, China. Total Hg (THg) and MeHg in soils and rice grains, together with sulfur (S), selenium (Se), organic matter (OM), nitrogen (N), phosphorus (P), mineral compositions (e.g., SiO₂, Al₂O₃ and Fe₂O₃) and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg-S(N)-OM complexes in rhizosphere. The Hg-Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.

Clinical and molecular epidemiologic characteristics of carbapenem-resistant Klebsiella pneumoniae infection/colonization among neonates in China

BACKGROUND

The spread of carbapenem-resistant Klebsiella pneumoniae (CR-KPN) is a major concern, but data on CR-KPN infection/colonization in paediatric populations are limited.

AIM

To analyse epidemiologic and clinical characteristics, and therapeutic options for CR-KPN infections in neonates in China.

METHODS

A retrospective study was performed at the Children's Hospital of Fudan University, including 88 neonates with CR-KPN admitted between November 2015 and October 2016. Forty-seven CR-KPN isolates were chosen at random for further study, including antimicrobial susceptibility testing, potential β-lactamase screening and homology analysis.

FINDINGS

In total, 44.3% (39/88) of the neonates with CR-KPN were infected, and 71.8% (28/39) were nosocomial infections. Of these, pneumonia and urinary tract infection accounted for 50.0% (14/28) and 42.9% (12/28), respectively. All infected patients were cured or improved with fosfomycin and/or carbapenem-containing combination therapy, except one case in whom treatment was withdrawn. All 47 cases of CR-KPN were resistant to ertapenem and 95.7% were resistant to imipenem/meropenem. Overall, 87.2% (41/47) were positive for bla_NDM-1, and belonged to 11 pulsed-field gel electrophoresis types; 53.7% (22/41) were designated as ST278 and 17.1% (7/41) were designated as ST2735 by multi-locus sequence typing.

CONCLUSIONS

Most of the CR-KPN isolated from neonates produced New Delhi metallo-beta-lactamase-1 and were highly homologous. Fosfomycin-containing regimens and meropenem-/panipenem-containing combination therapy were efficient for CR-KPN infection in neonates.

Methylmercury production in soil in the water-level-fluctuating zone of the Three Gorges Reservoir, China: The key role of low-molecular-weight organic acids

As important parts of dissolved organic matter, low-molecular-weight organic acids (LMWOAs) typically play important roles in desorbing Hg(II) from the soil solid-phase, which may directly or indirectly impact methylmercury (MeHg) production. However, the mechanism of these processes remains unclear. To better understand the effects of LMWOAs on Hg methylation in the soil, a field study was conducted to investigate the distribution of LMWOAs and their relationship with soil MeHg in a seasonally inundated area in the Three Gorges Reservoir (TGR), China. Meanwhile, laboratory simulation experiments were performed to determine the potential mechanism of LMWOAs in Hg methylation. The field investigation detected considerable amounts of LMWOAs in soil, among which tartaric acid and oxalic acid were dominant components. Among which, tartaric acid and oxalic acid were dominant components. Also, a seasonally and spatially heterogeneous distribution of LMWOAs in soil was observed. Notably, a significant positive relationship was found between MeHg concentrations and LMWOA pools in soil (r = 0.969, p < .01), implying that LMWOAs could promote soil MeHg production. The simulation experiments confirmed that the MeHg levels in soil were largely elevated with the addition of LMWOAs, which occurred mainly in oxygen-deficient environment and was mediated by biotic factors. The soluble Hg-LMWOA complexes, which were formed by the enhanced desorption of Hg(II) from solid-phase, were mostly responsible for the elevated MeHg production in soil. Moreover, those LMWOAs with more carboxylic groups were believed to enhance the net production of MeHg. The generated MeHg in sediment could diffuse into the overlying water, which thus poses a potential threat to the aquatic food web. Therefore, the enhanced Hg methylation caused by LMWOAs should be given more attention, especially in a seasonally inundated ecosystem, where the MeHg exposure is usually related to fishery activities.

Stronger selective constraint on downstream genes in the oxidative phosphorylation pathway of cetaceans

The oxidative phosphorylation (OXPHOS) pathway is an efficient way to produce energy via adenosine triphosphate (ATP), which is critical for sustaining an energy supply for cetaceans in a hypoxic environment. Several studies have shown that natural selection may shape the evolution of the genes involved in OXPHOS. However, how network architecture drives OXPHOS protein sequence evolution remains poorly explored. Here, we investigated the evolutionary patterns of genes in the OXPHOS pathway across six cetacean genomes within the framework of a functional network. Our results show a negative correlation between the strength of purifying selection and pathway position. This result indicates that downstream genes were subjected to stronger evolutionary constraints than upstream genes, which may be due to the dual function of ATP synthase in the OXPHOS pathway. Additionally, there was a positive correlation between codon usage bias and omega (ω = dN/dS) and a negative correlation with synonymous substitution rate (dS), indicating that the stronger selective constraint on genes (with less biased codon usage) along the OXPHOS pathway is attributable to an increase in the rate of synonymous substitution. Surprisingly, there was no significant correlation between protein-protein interactions and the evolutionary estimates, implying that highly connected enzymes may not always show greater evolutionary constraints. Compared with that observed for terrestrial mammals, we found that the signature of positive selection detected in five genes (ATP5J, LHPP, PPA1, UQCRC1 and UQCRQ) was cetacean-specific, reflecting the importance of OXPHOS for survival in hypoxic, aquatic environments.