Publications by authors named "Xue-Yan Liu"

48 Publications

Significant contributions of combustion-related NH and non-fossil fuel NO to elevation of nitrogen deposition in southwestern China over past five decades.

Glob Chang Biol 2021 Jun 5. Epub 2021 Jun 5.

School of Earth System Science, Tianjin University, Tianjin, China.

Anthropogenic nitrogen (N) emissions and deposition have been increasing over past decades. However, spatiotemporal variations of N deposition levels and major sources remain unclear in many regions, which hinders making strategies of emission mitigation and evaluating effects of elevated N deposition. By investigating moss N contents and δ N values in southwestern (SW) China in 1954-1964, 1970-1994, and 2005-2015, we reconstructed fluxes and source contributions of atmospheric ammonium ( ) and nitrate ( ) deposition and evaluated their historical changes. For urban and non-urban sites, averaged moss N contents did not differ between 1954-1964 and 1970-1994 (1.2%-1.3%) but increased distinctly in 2005-2015 (1.6%-2.3%), and averaged moss δ N values decreased from +0.4‰ to +3.3‰ in 1954-1964 to -1.9‰ to -0.7‰ in 1974-1990, and to -4.8‰ to -3.6‰ in 2005-2015. Based on quantitative estimations, N deposition levels from the 1950s to the 2000s did not change in the earlier 20 years but were elevated substantially in the later 30 years. Moreover, the elevation of deposition (by 12.2 kg-N/ha/year at urban sites and 4.6 kg-N/ha/year at non-urban sties) was higher than that of deposition (by 6.0 and 2.9 kg-N/ha/year, respectively) in the later 30 years. This caused a shifted dominance from to in N deposition. Based on isotope source apportionments, contributions of combustion-related NH sources (vehicle exhausts, coal combustion, and biomass burning) to the elevation of deposition were two times higher than volatilization NH sources (wastes and fertilizers) in the later 30 years. Meanwhile, non-fossil fuel NO sources (biomass burning, microbial N cycles) contributed generally more than fossil fuel NO sources (vehicle exhausts and coal combustion) to the elevation of deposition. These results revealed significant contributions of combustion-related NH and non-fossil fuel NO emissions to the historical elevation of N deposition in SW China, which is useful for emission mitigation and ecological effect evaluation of atmospheric N loading.
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http://dx.doi.org/10.1111/gcb.15736DOI Listing
June 2021

Completed absorption of coronavirus disease 2019 (COVID-19) pneumonia lesions: a preliminary study.

Int J Med Sci 2021 3;18(11):2321-2326. Epub 2021 Apr 3.

Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.

Complete absorption of coronavirus disease 2019 (COVID-19) pneumonia in a short term was not detailedly reported. We aimed to investigate the clinical and imaging characteristics of COVID-19 patients with complete absorption of pulmonary lesions. Retrospectively collected the clinical and chest CT data of 224 patients with COVID-19 in one regional medical center. Currently, pulmonary lesions in 37 patients were completely absorbed. The clinical manifestations, laboratory examinations, and CT findings of lesions for these patients were summarized. Among the 37 patients (age, 39.0 ± 12.4 [14-63] years, 20 males), disease in 36 (97.3%) was mild and in 1 (2.7%) was from severe to mild. The most common symptoms were cough (24/37, 64.9%) and fever (23/37, 62.2%). Their laboratory indicators at admission were usually normal, while the white blood cell and neutrophil count significantly increased at discharge (p = 0.004, p = 0.006). On initial CT images, all patients had various pulmonary lesions (mean involved lobes: 2.8 ± 1.5, range: 1-5; mean involved segments: 6.6 ± 4.3, range: 1-16), which mainly manifested as multiple patchy and or spherical ground glass opacities (GGOs) (30/37, 81.1%) with fibrous strips (19/30, 63.3%) or consolidation (11/30, 36.7%). After treatment, lesions in most (33/37, 89.2%) patients were continuously absorbed. At discharge, previous lesions were mostly absorbed in 11 patients (11/37, 29.7%), the main residues were GGOs (24/37, 64.9%), followed by fibrous strips (13/37, 35.1%). On the latest CT, all the pulmonary lesions were completely absorbed, the duration of lesions was 31.6 ± 11.4 days (range: 5-50 days). The pulmonary lesions in some mild COVID-19 patients (generally with normal laboratory indicators at admission, GGOs as the main manifestation on initial CT, and representation of continuous absorption after treatment) could be completely absorbed with a mean duration of 31.6 days.
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http://dx.doi.org/10.7150/ijms.54675DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8100646PMC
May 2021

The timing of continuous renal replacement therapy initiation in sepsis-associated acute kidney injury in the intensive care unit: the CRTSAKI Study (Continuous RRT Timing in Sepsis-associated AKI in ICU): study protocol for a multicentre, randomised controlled trial.

BMJ Open 2021 02 19;11(2):e040718. Epub 2021 Feb 19.

Intensive Care Unit, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China

Introduction: Acute kidney injury (AKI) is one of the most common organ dysfunction in sepsis, and increases the risk of unfavourable outcomes. Renal replacement therapy (RRT) is the predominant treatment for sepsis-associated AKI (SAKI). However, to date, no prospective randomised study has adequately addressed whether initiating RRT earlier will attenuate renal injury and improve the outcome of sepsis. The objective of the trial is to compare the early strategy with delayed strategy on the outcomes in patients with SAKI in the intensive care unit (ICU).

Methods And Analysis: This is a large-scale, multicentre, randomised controlled trial about SAKI. In total, 460 patients with sepsis and evidence of AKI stage 2 of Kidney Disease Improving Global Outcomes (KDIGO) will be recruited and equally randomised into the early group and the delay group in a ratio of 1:1. In the early group, continuous RRT (CRRT) will be started immediately after randomisation. In the delay group, CRRT will initiated if at least one of the following criteria was met: stage 3 of KDIGO, severe hyperkalaemia, pulmonary oedema, blood urea nitrogen level higher than 112 mg/dL after randomisation. The primary outcome is overall survival in a 90-day follow-up period (90-day all-cause mortality). Other end points include 28-day, 60-day and 1-year mortality, recovery rate of renal function by day 28 and day 90, ICU and hospital length of stay, the numbers of CRRT-free days, mechanical ventilation-free days and vasopressor-free days, the rate of complications potentially related to CRRT, CRRT-related cost, and concentrations of inflammatory mediators in serum.

Ethics And Dissemination: The trial has been approved by the Clinical Research and Application Institutional Review Board of the Second Affiliated Hospital of Guangzhou Medical University (2017-31-ks-01). Participants will be screened and enrolled from patients in the ICU with SAKI by clinicians, with no public advertisement for recruitment. Results will be disseminated in research journals and through conference presentations.

Trial Registration: NCT03175328.
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http://dx.doi.org/10.1136/bmjopen-2020-040718DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7896624PMC
February 2021

Important contributions of non-fossil fuel nitrogen oxides emissions.

Nat Commun 2021 01 11;12(1):243. Epub 2021 Jan 11.

School of Earth System Science, Tianjin University, 300072, Tianjin, China.

Since the industrial revolution, it has been assumed that fossil-fuel combustions dominate increasing nitrogen oxide (NO) emissions. However, it remains uncertain to the actual contribution of the non-fossil fuel NO to total NO emissions. Natural N isotopes of NO in precipitation (δN) have been widely employed for tracing atmospheric NO sources. Here, we compiled global δN observations to evaluate the relative importance of fossil and non-fossil fuel NO emissions. We found that regional differences in human activities directly influenced spatial-temporal patterns of δN variations. Further, isotope mass-balance and bottom-up calculations suggest that the non-fossil fuel NO accounts for 55 ± 7% of total NO emissions, reaching up to 21.6 ± 16.6Mt yr in East Asia, 7.4 ± 5.5Mt yr in Europe, and 21.8 ± 18.5Mt yr in North America, respectively. These results reveal the importance of non-fossil fuel NO emissions and provide direct evidence for making strategies on mitigating atmospheric NO pollution.
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http://dx.doi.org/10.1038/s41467-020-20356-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7801390PMC
January 2021

Development of a risk scoring system for prognostication in HIV-related toxoplasma encephalitis.

BMC Infect Dis 2020 Dec 4;20(1):923. Epub 2020 Dec 4.

Division of Infectious Diseases, Chongqing Public Health Medical Center, 109 Baoyu Road, Shapingba, Chongqing, China.

Background: This study aims to evaluate specific risk factors influencing prognosis of HIV-infected patients with toxoplasma encephalitis (TE) in order to develop a prognostic risk scoring system for them.

Methods: This is a six-center retrospective study of hospitalized HIV/TE patients. Data including six-week mortality after diagnosis, baseline characteristics, clinical features, laboratory tests and radiological characteristics of eligible patients were assimilated for risk model establishing.

Results: In this study, the six-week mortality among 94 retrospective cases was 11.7% (11/94). Seven specific risk factors, viz. time from symptom onset to presentation, fever, dizziness, CD4+ T-cell counts, memory deficits, patchy brain lesions, and disorders of consciousness were calculated to be statistically associated with mortality. A criterion value of '9' was selected as the optimal cut-off value of the established model. The AUC of the ROC curve of this scoring model was 0.976 (p < 0.001). The sensitivity and specificity of the risk scoring model was 100.0 and 86.9%, respectively, which were 81.8 and 94.1% of this scoring model in the verification cohort, respectively.

Conclusions: The developed scoring system was established with simple risk factors, which also allows expeditious implementation of accurate prognostication, and appropriate therapeutic interventions in HIV-infected patients with TE.
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http://dx.doi.org/10.1186/s12879-020-05651-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7716502PMC
December 2020

The Clinical Features and Prognostic Assessment of SARS-CoV-2 Infection-Induced Sepsis Among COVID-19 Patients in Shenzhen, China.

Front Med (Lausanne) 2020 15;7:570853. Epub 2020 Oct 15.

Department of Critical Care Medicine, The Second People's Hospital of Shenzhen, Shenzhen, China.

The outbreak of the novel coronavirus disease (COVID-19) that began in December 2019 has posed a great threat to human health and caused a significant loss of life. In Shenzhen, 465 patients were confirmed to have COVID-19 as of August 31, 2020. In the present study, we aimed to describe the clinical characteristics of COVID-19 patients in Shenzhen and identify risk factors for the development of viral sepsis. In this retrospective study, patients who were confirmed to have a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and were admitted to the Third People's Hospital of Shenzhen from January 11 to April 27, 2020 were included in the cohort. Clinical data were extracted and followed up to May 10, 2020, by using predesigned data collection forms. A total of 422 hospitalized COVID-19 patients were enrolled in this study, including 97 (23%) patients with viral sepsis at hospital admission and 325 (77%) non-septic patients. Patients with sepsis were much older than those without sepsis (57 vs. 43 years, < 0.001) and presented with more comorbidities. Septic patients showed multiple organ dysfunction and significant abnormalities in immune- and inflammation-related biomarkers, and had poorer outcomes when compared to those without sepsis. Increased levels of interleukin-6, blood urea nitrogen, and creatine kinase were associated with the development of SARS-CoV-2-induced sepsis, and an elevated production of interleukin-6 was found to be an independent risk factor for the progression to critical illness among septic COVID-19 patients. SARS-CoV-2 infection-induced sepsis is critically involved in the severity and prognosis of COVID-19 patients by characterizing both aberrant immune response and uncontrolled inflammation. The development of sepsis might contribute to multiple organ dysfunction and poor outcomes in COVID-19 patients during hospitalization.
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http://dx.doi.org/10.3389/fmed.2020.570853DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7593782PMC
October 2020

Knockdown of lncRNA MALAT1 Alleviates LPS-Induced Acute Lung Injury via Inhibiting Apoptosis Through the miR-194-5p/FOXP2 Axis.

Front Cell Dev Biol 2020 7;8:586869. Epub 2020 Oct 7.

Department of Critical Care Medicine, Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China.

Purpose: We aimed to identify and verify the key genes and lncRNAs associated with acute lung injury (ALI) and explore the pathogenesis of ALI. Research showed that lower expression of the lncRNA metastasis-associated lung carcinoma transcript 1 (MALAT1) alleviates lung injury induced by lipopolysaccharide (LPS). Nevertheless, the mechanisms of MALAT1 on cellular apoptosis remain unclear in LPS-stimulated ALI. We investigated the mechanism of MALAT1 in modulating the apoptosis of LPS-induced human pulmonary alveolar epithelial cells (HPAEpiC).

Methods: Differentially expressed lncRNAs between the ALI samples and normal controls were identified using gene expression profiles. ALI-related genes were determined by the overlap of differentially expressed genes (DEGs), genes correlated with lung, genes correlated with key lncRNAs, and genes sharing significantly high proportions of microRNA targets with MALAT1. Quantitative real-time PCR (qPCR) was applied to detect the expression of MALAT1, microRNA (miR)-194-5p, and forkhead box P2 (FOXP2) mRNA in 1 μg/ml LPS-treated HPAEpiC. MALAT1 knockdown vectors, miR-194-5p inhibitors, and ov-FOXP2 were constructed and used to transfect HPAEpiC. The influence of MALAT1 knockdown on LPS-induced HPAEpiC proliferation and apoptosis via the miR-194-5p/FOXP2 axis was determined using Cell counting kit-8 (CCK-8) assay, flow cytometry, and Western blotting analysis, respectively. The interactions between MALAT1, miR-194-5p, and FOXP2 were verified using dual-luciferase reporter gene assay.

Results: We identified a key lncRNA (MALAT1) and three key genes (EYA1, WNT5A, and FOXP2) that are closely correlated with the pathogenesis of ALI. LPS stimulation promoted MALAT1 expression and apoptosis and also inhibited HPAEpiC viability. MALAT1 knockdown significantly improved viability and suppressed the apoptosis of LPS-stimulated HPAEpiC. Moreover, MALAT1 directly targeted miR-194-5p, a downregulated miRNA in LPS-stimulated HPAEpiC, when FOXP2 was overexpressed. MALAT1 knockdown led to the overexpression of miR-194-5p and restrained FOXP2 expression. Furthermore, inhibition of miR-194-5p exerted a rescue effect on MALAT1 knockdown of FOXP2, whereas the overexpression of FOXP2 reversed the effect of MALAT1 knockdown on viability and apoptosis of LPS-stimulated HPAEpiC.

Conclusion: Our results demonstrated that MALAT1 knockdown alleviated HPAEpiC apoptosis by competitively binding to miR-194-5p and then elevating the inhibitory effect on its target FOXP2. These data provide a novel insight into the role of MALAT1 in the progression of ALI and potential diagnostic and therapeutic strategies for ALI patients.
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http://dx.doi.org/10.3389/fcell.2020.586869DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575725PMC
October 2020

Coronavirus disease 2019 (COVID-19) associated coagulopathy and its impact on outcomes in Shenzhen, China: A retrospective cohort study.

Thromb Res 2020 11 9;195:62-68. Epub 2020 Jul 9.

Department of Critical Care Medicine and Infection Prevention and Control, The Second People's Hospital of Shenzhen & First Affiliated Hospital of Shenzhen University, Health Science Center, Shenzhen, People's Republic of China. Electronic address:

Background: Early detection of suspected critical patients infected with coronavirus disease 2019 (COVID-19) is very important for the treatment of patients. This study aimed to investigate the role of COVID-19 associated coagulopathy (CAC) to preview and triage.

Methods And Results: A cohort study was designed from government designated COVID-19 treatment center. CAC was defined as International Society on Thrombosis and Haemostasis (ISTH) score ≥2. Data from 117 patients COVID-19 were reviewed on admission. The primary and secondary outcomes were admission to Intensive Care Unit (ICU), the use of mechanical ventilation, vital organ dysfunction, discharges of days 14, 21 and 28 from admission and hospital mortality. Among them, admission to ICU was increased progressively from 16.1% in patients with non-CAC to 42.6% in patients with CAC (P < 0.01). Likely, invasive ventilation and noninvasive ventilation were increased from 1.8%, 21.4% in patients with non-CAC to 21.3%, 52.5% in patients with CAC, respectively (P < 0.01). The incidences of acute hepatic injury and acute respiratory distress syndrome in non-CAC and CAC were 28.6% vs. 62.3%, 8.9% vs. 27.9%, respectively (P < 0.01). The discharges of days 14, 21 and 28 from admission were more in non-CAC than those of CAC (P < 0.05). Multiple logistic regression results showed that ISTH score ≥2 was obviously associated with the admission to ICU (OR 4.07, 95% CI 1.47-11.25 P = 0.007) and the use of mechanical ventilation (OR 5.54, 95% CI 2.01-15.28 P = 0.001) in patients with COVID-19.

Conclusion: All results show ISTH score ≥2 is an important indicator to preview and triage for COVID-19 patients.
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http://dx.doi.org/10.1016/j.thromres.2020.07.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7347306PMC
November 2020

COVID-19 managed with early non-invasive ventilation and a bundle pharmacotherapy: A case report.

World J Clin Cases 2020 May;8(9):1705-1712

Department of Dermatology, Shenzhen University General Hospital, Shenzhen 518067, Guangdong Province, China.

Background: The coronavirus disease 2019 (COVID-19) pandemic has become an immense public health burden, first in China and subsequently worldwide. Developing effective control measures for COVID-19, especially measures that can halt the worsening of severe cases to a critical status is of urgent importance.

Case Summary: A 52-year-old woman presented with a high fever (38.8 °C), chills, dizziness, and weakness. Epidemiologically, she had not been to Wuhan where COVID-19 emerged and did not have a family history of a disease cluster. A blood test yielded a white blood cell count of 4.41 × 10/L (60.6 ± 2.67% neutrophils and 30.4 ± 1.34% lymphocytes). Chest imaging revealed bilateral ground-glass lung changes. Based on a positive nasopharyngeal swab nucleic acid test result and clinical characteristics, the patient was diagnosed with COVID-19. Following treatment with early non-invasive ventilation and a bundle pharmacotherapy, she recovered with a good outcome.

Conclusion: Early non-invasive ventilation with a bundle pharmacotherapy may be an effective treatment regimen for the broader population of patients with COVID-19.
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http://dx.doi.org/10.12998/wjcc.v8.i9.1705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211518PMC
May 2020

Levels and variations of soil organic carbon and total nitrogen among forests in a hotspot region of high nitrogen deposition.

Sci Total Environ 2020 Apr 13;713:136620. Epub 2020 Jan 13.

Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China.

Human activities have distinctly enhanced the deposition levels of atmospheric nitrogen (N) pollutants into terrestrial ecosystems, but whether and to what extents soil carbon (C) and N status have been influenced by elevated N inputs remain poorly understood in the 'real' world given related knowledge has largely based on N-addition experiments. Here we reported soil organic C (OC) and total N (TN) for twenty-seven forests along a gradient of N deposition (22.4-112.9 kg N/ha/yr) in the Beijing-Tianjin-Hebei (BTH) region of northern China, a global hotspot of high N pollution. Levels of soil TN in forests of the BTH region have been elevated compared with investigations in past decades, suggesting that long-term N deposition might cause soil TN increases. Combining with major geographical and environmental factors among the study forests, we found unexpectedly that soil moisture and pH values rather than N deposition levels were major regulators of the observed spatial variations of soil OC and TN contents. As soil moisture and pH values increased with mean annual precipitation and temperature, respectively, soil C and N status in forests of the BTH region might be more responsive to climate change than to N pollution. These evidence suggests that both N deposition and climate differences should be considered into managing ecosystem functions of forest resources in regions with high N pollution.
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http://dx.doi.org/10.1016/j.scitotenv.2020.136620DOI Listing
April 2020

Nitrogen isotope differences between atmospheric nitrate and corresponding nitrogen oxides: A new constraint using oxygen isotopes.

Sci Total Environ 2020 Jan 14;701:134515. Epub 2019 Nov 14.

Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China.

Tracking of reactive nitrogen (N) sources is important for the effective mitigation of N emissions. By combining the N and oxygen (O) isotopes of atmospheric NO, stable isotope mixing models were recently applied to evaluate the relative contributions of major NO sources. However, it has long been unresolved how to accurately constrain the δN differences between NO and corresponding NO (ε values). Here, we first incorporated the HC oxidation (NO → NO) pathway by using ΔO values to evaluate the ε values, performed on NO in PM collected during the day and at night from January 4-13, 2015 at an urban site in Beijing. We found that the ΔO-based ε values (ε) (15.6 ± 7.4‰) differed distinctly from δO-based ε values (ε) (33.0 ± 9.5‰) so did not properly incorporate the isotopic effects of the HC oxidation (NO → NO) pathway. Based on the ε values, δN values of NO from coal combustion (CC), vehicle exhausts (VE), biomass burning (BB), and the microbial N cycle (MC), as well as NO in PM, we further quantified the source contributions by using Stable Isotope Analysis in R (the SIAR model). We found that the respective fractional contributions of CC-NO and MC-NO were underestimated by 64% and were overestimated by 216% by using ε values. We concluded that the new ε values reduced uncertainties in contribution analysis and the evaluation method for atmospheric NO sources.
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http://dx.doi.org/10.1016/j.scitotenv.2019.134515DOI Listing
January 2020

Attenuation of hyperoxic acute lung injury by Lycium barbarum polysaccharide via inhibiting NLRP3 inflammasome.

Arch Pharm Res 2019 Oct 6;42(10):902-908. Epub 2019 Aug 6.

Shenzhen People's Hospital, The Second Clinical Medicine College of Jinan University, Shenzhen, 518000, China.

Lycium barbarum polysaccharide (LBP), an active component from Goji berry which is a traditional Chinese medicine, has anti-inflammatory and antioxidant features. The aim of our study was to investigate whether LBP has any role in hyperoxia-induced acute lung injury (ALI). Using a murine model of hyperoxia-induced ALI, we investigate the effect of LBP on pulmonary pathological changes as well as Sirtuin 1 (SIRT1) and the nucleotide binding domain and leucine-rich repeat pyrin domain containing 3 (NLRP3) inflammasome. Exposure to 100% oxygen for 72 h in male C57BL/6 mice resulted in increased protein levels of tumor necrosis factor-α and interleukin-1β in lung tissues, and aggravated lung histological alterations. These hyperoxia-induced changes and mortality were improved by LBP. LBP markedly suppressed the activation of NLRP3 inflammasome both in vivo and in vitro. Moreover, LBP upregulated SIRT1 expression compared with vehicle-treated group. Importantly, knockdown of SIRT1 reversed the inhibitory effect of LBP on NLRP3 inflammasome activation in vitro. LBP meliorated hyperoxia-induced ALI in mice by SIRT1-dependent inhibition of NLRP3 inflammasome activation.
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http://dx.doi.org/10.1007/s12272-019-01175-4DOI Listing
October 2019

microRNA-30a inhibits the liver cell proliferation and promotes cell apoptosis through the JAK/STAT signaling pathway by targeting SOCS-1 in rats with sepsis.

J Cell Physiol 2019 08 10;234(10):17839-17853. Epub 2019 Apr 10.

Integrated Chinese and Western Medicine Postdoctoral Research Station, Jinan University, Shenzhen, People's Republic of China.

Sepsis is a systemic inflammatory response that may be induced by trauma, infection, surgery, and burns. With the aim of discovering novel treatment targets for sepsis, this current study was conducted to investigate the effect and potential mechanism by which microRNA-30a (miR-30a) controls sepsis-induced liver cell proliferation and apoptosis. Rat models of sepsis were established by applying the cecal ligation and puncture (CLP) method to simulate sepsis models. The binding site between miR-30a and suppressor of cytokine signaling protein 1 (SOCS-1) was determined by dual luciferase reporter gene assay. The gain-of-and-loss-of-function experiments were applied to analyze the effects of miR-30a and SOCS-1 on liver cell proliferation and apoptosis of the established sepsis rat models. The expression of miR-30a, SOCS-1, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), Bcl-2 associated X protein (Bax), B cell lymphoma-2 (Bcl-2), toll-like receptor 4 (TLR4), and high-mobility group box 1 (HMGB1), and the extent of JAK2 and STAT3 phosphorylation were all determined. Sepsis led to an elevation of miR-30a and also a decline of SOCS-1 in the liver cells. SOCS-1 was negatively regulated by miR-30a. Upregulated miR-30a and downregulated SOCS-1 increased the expression of JAK2, STAT3, Bax, TLR4, and HMGB1 as well as the extent of JAK2 and STAT3 phosphorylation whereas impeding the expression of SOCS-1 and Bcl-2. More important, either miR-30a elevation or SOCS-1 silencing suppressed liver cell proliferation and also promoted apoptosis. On the contrary, the inhibition of miR-30a exhibited the opposite effects. Altogether, we come to the conclusion that miR-30a inhibited the liver cell proliferation and promoted cell apoptosis by targeting and negatively regulating SOCS-1 via the JAK/STAT signaling pathway in rats with sepsis.
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http://dx.doi.org/10.1002/jcp.28410DOI Listing
August 2019

Isotopic evaluation on relative contributions of major NO sources to nitrate of PM in Beijing.

Environ Pollut 2019 May 28;248:183-190. Epub 2019 Jan 28.

Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China. Electronic address:

Nitrate (NO) is a key component of secondary inorganic aerosols and PM. However, the contributions of nitrogen oxides (NO) emission sources to NO in PM remain poorly constrained. This study measured nitrogen (N) isotopes of NO (hereafter as δN-NO) in PM collected at Beijing in 2014. We observed that δN-NO values in PM (-2.3‰ - 19.7‰; 7.3 ± 5.4‰ annually) were significantly higher in winter (11.9 ± 4.4‰) than in summer (2.2 ± 2.5‰). The δN differences between source NO and NO in PM (hereafter as Δ values) were estimated by a computation module as 7.8 ± 2.2‰ - 10.4 ± 1.6‰ (8.8 ± 2.4‰). Using the Δ values and δN values of NO from major fossil (coal combustion, vehicle exhausts) and non-fossil sources (biomass burning, microbial N cycle), contributions of major NO sources to NO in PM were further estimated by the SIAR model. We found that seasonal variations of δN-NO values in PM of Beijing were mainly caused by those of NO contributions from coal combustion (38 ± 10% in winter, 20 ± 9% in summer). Annually, NO from coal combustion, vehicle exhausts, biomass burning, and microbial N cycle contributed 28 ± 12%, 29 ± 17%, 27 ± 15%, and 16 ± 7% to NO in PM, respectively, showing actually comparable contributions between non-fossil NO (43 ± 16%) and fossil NO (57 ± 21%). These results are useful for planning the reduction of NO emissions in city environments and for elucidating relationships between regional NO emissions and atmospheric NO pollution or deposition.
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http://dx.doi.org/10.1016/j.envpol.2019.01.081DOI Listing
May 2019

Ketogenic diet effects on 52 children with pharmacoresistant epileptic encephalopathy: A clinical prospective study.

Brain Behav 2018 05 18;8(5):e00973. Epub 2018 Apr 18.

Department of Radiology Shengjing Hospital of China Medical University Shenyang China.

Objective: To evaluate the clinical impact of ketogenic diet (KD) on children with pharmacoresistant epileptic encephalopathy.

Methods: In all, 52 children with pharmacoresistant epileptic encephalopathy that diagnosed in our hospital from July 2012 to June 2015 were selected, including West syndrome 38 cases, Lennox-Gastaut Syndrome 7 cases, Doose Syndrome 1 case, and Dravet syndrome 6 cases, and the effect, compliance, adverse reactions, electroencephalogram (EEG), and cognitive function were analyzed. Modified Johns Hopkins protocol was used to initiate KD, and Engel scale was used to evaluate the effect, and evaluated the effect of KD on the cognition, language, and motor function.

Results: At 12 weeks of KD treatment, the patients achieved I, II, III, and IV grade effect were accounted for 26.9% (14/52 cases), 17.3% (9/52 cases), 11.5% (6/52 cases), and 44.2% (23/52 cases), respectively, according to Engel scale. KD has different effect on different epileptic syndromes, best effect on Doose syndromes of 100%, and better effect on West syndrome with the effect rate of 57.9%, and the total effect number was 22 cases. The reduction of epileptiform discharges in the awake state before KD treatment was correlated with the seizure time after 3 months of KD treatment (=.330,  = .017). The cognitive function of 23 patients was improved, 12 patients had language improvement, and the motor function was improved in 10 patients. In all, 23 patients had adverse reactions, and all patients were tolerated and improved.

Conclusion: KD has certain effect on children with pharmacoresistant epileptic encephalopathy, and it can reduce interictal epileptic discharge frequency, and improve the background rhythm of EEG. The reduction of epileptiform discharges in awake state is in favor of the reduction of seizures frequency, thus increasing the efficacy, and improve the cognitive function, language, and motor function to varying degrees, combined with less adverse reaction, which is worthy of clinical application.
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http://dx.doi.org/10.1002/brb3.973DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5943818PMC
May 2018

Nitrogen isotope variations of ammonium across rain events: Implications for different scavenging between ammonia and particulate ammonium.

Environ Pollut 2018 Aug 17;239:392-398. Epub 2018 Apr 17.

Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.

Enhanced ammonia (NH) emissions and deposition caused negative effects on air quality and ecosystems. Precipitation is an efficient pathway to remove NH and particulate ammonium (p-NH) from the atmosphere into ecosystems. However, precipitation scavenging of p-NH in chemical transport models has often considered fine p-NH, with inadequate constraints on NH and coarse p-NH. Based on distinct δN values between NH and NH in PM (particulate matters with aerodynamic diameters ≤ 2.5 μm) or TSP (total suspended particulates), this paper interpreted intra-event variations of precipitation NH concentrations and δN values (δN-NH values) at Guiyang (Xiao et al., 2015). Generally decreased NH concentrations across rain events reflected decreasing scavenging of NH and p-NH. Using a Bayesian isotope mixing model, we found that differing contributions between N-depleted NH and N-enriched p-NH were responsible for the three-stage variations of intra-event δN-NH values. The decreases of δN-NH values across the first and third stages indicated more decreases in scavenging p-NH than NH, while the increases of δN-NH values across the second stage were resulted primarily from more increases in scavenging p-NH (particularly fine p-NH) than NH. These results stressed influences of differing scavenging between NH and p-NH on precipitation δN-NH values, which should be considered in modeling precipitation scavenging of atmospheric p-NH.
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http://dx.doi.org/10.1016/j.envpol.2018.04.015DOI Listing
August 2018

Nitrate is an important nitrogen source for Arctic tundra plants.

Proc Natl Acad Sci U S A 2018 03 14;115(13):3398-3403. Epub 2018 Mar 14.

Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China.

Plant nitrogen (N) use is a key component of the N cycle in terrestrial ecosystems. The supply of N to plants affects community species composition and ecosystem processes such as photosynthesis and carbon (C) accumulation. However, the availabilities and relative importance of different N forms to plants are not well understood. While nitrate (NO) is a major N form used by plants worldwide, it is discounted as a N source for Arctic tundra plants because of extremely low NO concentrations in Arctic tundra soils, undetectable soil nitrification, and plant-tissue NO that is typically below detection limits. Here we reexamine NO use by tundra plants using a sensitive denitrifier method to analyze plant-tissue NO Soil-derived NO was detected in tundra plant tissues, and tundra plants took up soil NO at comparable rates to plants from relatively NO-rich ecosystems in other biomes. Nitrate assimilation determined by N enrichments of leaf NO relative to soil NO accounted for 4 to 52% (as estimated by a Bayesian isotope-mixing model) of species-specific total leaf N of Alaskan tundra plants. Our finding that in situ soil NO availability for tundra plants is high has important implications for Arctic ecosystems, not only in determining species compositions, but also in determining the loss of N from soils via leaching and denitrification. Plant N uptake and soil N losses can strongly influence C uptake and accumulation in tundra soils. Accordingly, this evidence of NO availability in tundra soils is crucial for predicting C storage in tundra.
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http://dx.doi.org/10.1073/pnas.1715382115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5879661PMC
March 2018

Inter-species and intra-annual variations of moss nitrogen utilization: Implications for nitrogen deposition assessment.

Environ Pollut 2017 Nov 7;230:506-515. Epub 2017 Jul 7.

Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.

Moss nitrogen (N) concentrations and natural N abundance (δN values) have been widely employed to evaluate annual levels and major sources of atmospheric N deposition. However, different moss species and one-off sampling were often used among extant studies, it remains unclear whether moss N parameters differ with species and different samplings, which prevented more accurate assessment of N deposition via moss survey. Here concentrations, isotopic ratios of bulk carbon (C) and bulk N in natural epilithic mosses (Bryum argenteum, Eurohypnum leptothallum, Haplocladium microphyllum and Hypnum plumaeforme) were measured monthly from August 2006 to August 2007 at Guiyang, SW China. The H. plumaeforme had significantly (P < 0.05) lower bulk N concentrations and higher δC values than other species. Moss N concentrations were significantly (P < 0.05) lower in warmer months than in cooler months, while moss δC values exhibited an opposite pattern. The variance component analyses showed that different species contributed more variations of moss N concentrations and δC values than different samplings. Differently, δN values did not differ significantly between moss species, and its variance mainly reflected variations of assimilated N sources, with ammonium as the dominant contributor. These results unambiguously reveal the influence of inter-species and intra-annual variations of moss N utilization on N deposition assessment.
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http://dx.doi.org/10.1016/j.envpol.2017.06.058DOI Listing
November 2017

Stable isotope analyses of precipitation nitrogen sources in Guiyang, southwestern China.

Environ Pollut 2017 Nov 6;230:486-494. Epub 2017 Jul 6.

Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan; Center for Ecological Research, Kyoto University, Shiga, 520-2113, Japan.

To constrain sources of anthropogenic nitrogen (N) deposition is critical for effective reduction of reactive N emissions and better evaluation of N deposition effects. This study measured δN signatures of nitrate (NO), ammonium (NH) and total dissolved N (TDN) in precipitation at Guiyang, southwestern China and estimated contributions of dominant N sources using a Bayesian isotope mixing model. For NO, the contribution of non-fossil N oxides (NO, mainly from biomass burning (24 ± 12%) and microbial N cycle (26 ± 5%)) equals that of fossil NO, to which vehicle exhausts (31 ± 19%) contributed more than coal combustion (19 ± 9%). For NH, ammonia (NH) from volatilization sources (mainly animal wastes (22 ± 12%) and fertilizers (22 ± 10%)) contributed less than NH from combustion sources (mainly biomass burning (17 ± 8%), vehicle exhausts (19 ± 11%) and coal combustions (19 ± 12%)). Dissolved organic N (DON) accounted for 41% in precipitation TDN deposition during the study period. Precipitation DON had higher δN values in cooler months (13.1‰) than in warmer months (-7.0‰), indicating the dominance of primary and secondary ON sources, respectively. These results newly underscored the importance of non-fossil NO, fossil NH and organic N in precipitation N inputs of urban environments.
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http://dx.doi.org/10.1016/j.envpol.2017.06.010DOI Listing
November 2017

Comparison of Laparoscopic Distal Pancreatectomy with or without Splenic Preservation.

Indian J Surg 2015 Dec 4;77(Suppl 3):783-7. Epub 2013 Dec 4.

Department of HepatobiliaryPancreatic Surgery, First Hospital of Jilin University, Changchun, 130021 China.

Laparoscopic distal pancreatectomy (LDP) has gained large popularity in recent years, although the choice of whether to preserve the spleen has remained inconsistent. The aim of our study was to report our experiences with LDP and to provide evidence for the safety of the operative technique and an evaluation index of splenic function. We retrospectively evaluated all LDPs performed at our institution between March 2008 and February 2012. Cases were divided into a laparoscopic spleen-preserving distal pancreatectomy (LSPDP) group (n = 14) and an LDP with splenectomy (LDPS) group (n = 19). Parametric and nonparametric statistical analyses were used to compare perioperative and oncologic outcomes. Demographic characteristics, operating time, length of stay, estimated blood loss, transfusion requirement, pathologic diagnosis, and complication rate were similar between groups. Patients who underwent LDPS tended to have larger masses and lower pancreatic fistula rates, but these differences were not significant. White blood cell (WBC) counts were significantly higher in the LDPS group than in the LSPDP group on postoperative days 1 and 7. To avoid splenectomy-associated complications, preservation of the spleen and especially the splenic vessels are preferred. This procedure can be performed safely and feasibly. Lower postoperative WBC counts may imply better splenic function.
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http://dx.doi.org/10.1007/s12262-013-1002-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4775660PMC
December 2015

Successful salvage treatment of acute graft-versus-host disease after liver transplantation by withdrawal of immunosuppression: a case report.

Korean J Hepatobiliary Pancreat Surg 2016 Feb 19;20(1):38-43. Epub 2016 Feb 19.

Department of Hepato-biliary Pancreatic Surgery, First Hospital of Jilin University, Changchun, China.

Acute graft-versus-host disease (GVHD) following liver transplantation is a rare but fatal complication. The correct diagnosis and management of GVHD after liver transplantation are still major challenges. Herein, we reported successful salvage treatment of acute GVHD by withdrawal of immunosuppression in a patient who presented with fever, skin rashes, and decreased blood cell counts after liver transplantation. This case highlights the need for awareness of drug-induced liver injury if liver function tests are elevated during treatment, especially in patients taking multiple potentially hepatotoxic drugs, such as broad-spectrum antibiotics. When occurs, an artificial liver support system is a useful tool to provide temporary support of liver function for the patient in the event of drug-induced liver injury.
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http://dx.doi.org/10.14701/kjhbps.2016.20.1.38DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4767263PMC
February 2016

Nitrate dynamics in natural plants: insights based on the concentration and natural isotope abundances of tissue nitrate.

Front Plant Sci 2014 23;5:355. Epub 2014 Jul 23.

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences Guiyang, China.

The dynamics of nitrate (NO(-) 3), a major nitrogen (N) source for natural plants, has been studied mostly through experimental N addition, enzymatic assay, isotope labeling, and genetic expression. However, artificial N supply may not reasonably reflect the N strategies in natural plants because NO(-) 3 uptake and reduction may vary with external N availability. Due to abrupt application and short operation time, field N addition, and isotopic labeling hinder the elucidation of in situ NO(-) 3-use mechanisms. The concentration and natural isotopes of tissue NO(-) 3 can offer insights into the plant NO(-) 3 sources and dynamics in a natural context. Furthermore, they facilitate the exploration of plant NO(-) 3 utilization and its interaction with N pollution and ecosystem N cycles without disturbing the N pools. The present study was conducted to review the application of the denitrifier method for concentration and isotope analyses of NO(-) 3 in plants. Moreover, this study highlights the utility and advantages of these parameters in interpreting NO(-) 3 sources and dynamics in natural plants. We summarize the major sources and reduction processes of NO(-) 3 in plants, and discuss the implications of NO(-) 3 concentration in plant tissues based on existing data. Particular emphasis was laid on the regulation of soil NO(-) 3 and plant ecophysiological functions in interspecific and intra-plant NO(-) 3 variations. We introduce N and O isotope systematics of NO(-) 3 in plants and discuss the principles and feasibilities of using isotopic enrichment and fractionation factors; the correlation between concentration and isotopes (N and O isotopes: δ(18)O and Δ(17)O); and isotope mass-balance calculations to constrain sources and reduction of NO(-) 3 in possible scenarios for natural plants are deliberated. Finally, we offer a preliminary framework of intraplant δ(18)O-NO(-) 3 variation, and summarize the uncertainties in using tissue NO(-) 3 parameters to interpret plant NO(-) 3 utilization.
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http://dx.doi.org/10.3389/fpls.2014.00355DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108036PMC
August 2014

Correlation of expression of STAT3, VEGF and differentiation of Th17 cells in psoriasis vulgaris of guinea pig.

Asian Pac J Trop Med 2014 Apr;7(4):313-6

Department of Dermatology, South Hospital, Southern Medical University, Guangzhou 510000, China.

Objective: To investigate the role of T help 17 cells (Th17) and STAT3-VEGF pathway in pathogenesis of psoriasis.

Methods: A total of 50 cases of psoriasis guinea pigs and 20 normal guinea pigs were selected. The ratio of Th17/ IL-17 cell in peripheral blood were detected by flow cytometric analysis; STAT3 and VEGF concentrations were measured by immunohistochemistry and Western blot.

Results: The expression of Th17 in peripheral blood were significantly increased in psoriasis [(1.76±0.88)%] compared with controls [(0.48±0.27)%] (P<0.05). Th17 related cytokine STAT3 and VEGF were significantly increased in psoriasis compared with controls (P<0.05), and were positively correlated the expression of Th17.

Conclusions: The expressions of Th17, STAT3 and VEGF are elevated in psoriasis, which suggests Th17 cells have a potential role in the pathogenesis of psoriasis by STAT3-VEGF pathway.
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http://dx.doi.org/10.1016/S1995-7645(14)60046-8DOI Listing
April 2014

Leukemia inhibitory factor inhibits the proliferation of primary rat astrocytes induced by oxygen-glucose deprivation.

Acta Neurobiol Exp (Wars) 2013 ;73(4):485-94

Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China,

Leukemia inhibitory factor (LIF) is a neuroprotective cytokine that is necessary for the normal development of astrocytes. Oxygen-glucose deprivation (OGD) can induce astrocyte proliferation by increasing hypoxia-inducible factor alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF). Here, we studied whether LIF affects the proliferation of cultured primary rat astrocytes under OGD conditions by measuring EdU incorporation into astrocyte DNA and the expression of proliferating cell nuclear antigen (PCNA) mRNA and protein. Our findings show that low concentrations of LIF (5 and 10 ng/mL) significantly decreased EdU incorporation and downregulated the expression of PCNA mRNA and PCNA protein in astrocytes subjected to OGD. A low concentration of LIF (10 ng/mL) clearly inhibited astrocyte proliferation induced by OGD, while a higher concentration (50 ng/mL) had no effect. To investigate the mechanism of this inhibition by LIF (10 ng/mL), the expression of 3 related genes (LIF receptor, HIF-1alpha, and VEGF) was assessed using real-time PCR; VEGF protein expression was measured by Western blot. Our results indicate that LIFR mRNA was downregulated in astrocytes subjected to OGD. Interestingly, treatment with LIF further reduced LIFR mRNA expression in these cells. LIF treatment also decreased the expression of HIF-1alpha mRNA, VEGF mRNA, and VEGF protein induced by OGD. Low concentrations of LIF were observed to inhibit astrocyte proliferation induced by OGD.
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November 2014

Ammonium first: natural mosses prefer atmospheric ammonium but vary utilization of dissolved organic nitrogen depending on habitat and nitrogen deposition.

New Phytol 2013 Jul 21;199(2):407-419. Epub 2013 May 21.

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.

Mosses, among all types of terrestrial vegetation, are excellent scavengers of anthropogenic nitrogen (N), but their utilization of dissolved organic N (DON) and their reliance on atmospheric N remain uncharacterized in natural environments, which obscures their roles in N cycles. Natural (15) N abundance of N sources (nitrate (NO(3)(-)), ammonium (NH(4)(+)) and DON in deposition and soil) for epilithic and terricolous mosses was analyzed at sites with different N depositions at Guiyang, China. Moss NO(3)(-) assimilation was inhibited substantially by the high supply of NH(4)(+) and DON. Therefore, contributions of NH(4)(+) and DON to moss N were partitioned using isotopic mass-balance methods. The N contributions averaged 56% and 46% from atmospheric NH(4)(+), and 44% and 17% from atmospheric DON in epilithic and terricolous mosses, respectively. In terricolous mosses, soil NH(4)(+) and soil DON accounted for 16% and 21% of bulk N, which are higher than current estimations obtained using (15) N-labeling methods. Moreover, anthropogenic NH(4)(+) deposition suppressed utilization of DON and soil N because of the preference of moss for NH(4)(+) under elevated NH(4)(+) deposition. These results underscore the dominance of, and preference for, atmospheric NH(4)(+) in moss N utilization, and highlight the importance of considering DON and soil N sources when estimating moss N sequestration and the impacts of N deposition on mosses.
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http://dx.doi.org/10.1111/nph.12284DOI Listing
July 2013

LPS induces cardiomyocyte injury through calcium-sensing receptor.

Mol Cell Biochem 2013 Jul 8;379(1-2):153-9. Epub 2013 Apr 8.

Department of Neonatology, The First Clinical Hospital of Harbin Medical University, Harbin, China.

Calcium-sensing receptor (CaSR) belongs to the family C of G-protein coupled receptors. We have previously demonstrated that CaSR could induce apoptosis of cultured neonatal rat ventricular cardiomyocytes in simulated ischemia/reperfusion. It remains unknown whether the CaSR has function in lipopolysaccharide (LPS)-induced myocardial injure. The aim of this study was to investigate whether the CaSR plays a role in LPS-induced myocardial injury. Cultured neonatal rat cardiomyocytes were treated with LPS, with or without pretreatment with the CaSR-specific agonist gadolinium chloride (GdCl3) or the CaSR-specific antagonist NPS2390. Release of TNF-α and IL-6 from cardiomyocytes was observed. Levels of malonaldehyde (MDA), lactate dehydrogenase (LDH), and activity of superoxide dismutase (SOD) were measured. In addition, apoptosis of the cardiomyocytes, [Ca(2+)]i and level of CaSR expression were determined. The results showed that LPS increased cardiomyocytes apoptosis, [Ca(2+)]i, MDA, LDH, TNF-α, IL-6 release, and CaSR protein expression. Compared with LPS treatment alone, pretreatment with GdCl3 further increased apoptosis of cardiomyocytes, MDA, LDH, TNF-α, IL-6 release, [Ca(2+)]i, and the expression of the CaSR protein. Conversely, pretreatment with NPS2390 decreased apoptosis of cardiomyocytes, MDA, LDH, TNF-α, IL-6 release, [Ca(2+)]i and the expression of the CaSR protein. These results demonstrate that LPS could induce cardiomyocyte injury. Moreover, LPS-induced cardiomyocyte injury was related to CaSR-mediated cardiomyocytes apoptosis, TNF-α, IL-6 release, and increase of intracellular calcium.
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http://dx.doi.org/10.1007/s11010-013-1637-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666124PMC
July 2013

Pitfalls and new mechanisms in moss isotope biomonitoring of atmospheric nitrogen deposition.

Environ Sci Technol 2012 Nov 2;46(22):12557-66. Epub 2012 Nov 2.

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.

Moss N isotope (δ(15)N(bulk)) has been used to monitor N deposition, but it remains questionable whether inhibition of nitrate reductase activity (NRA) by reduced dissolved N (RDN) engenders overestimation of RDN in deposition when using moss δ(15)N(bulk). We tested this question by investigation of δ(15)N(bulk) and δ(15)NO(3)(-) in mosses under the dominance of RDN in N depositions of Guiyang, SW China. The δ(15)N(bulk) of mosses on bare rock (-7.9‰) was unable to integrate total dissolved N (TDN) (δ(15)N = -6.3‰), but it reflected δ(15)N-RDN (-7.5‰) exactly. Moreover, δ(15)N-NO(3)(-) in mosses (-1.7‰) resembled that of wet deposition (-1.9‰). These isotopic approximations, together with low isotopic enrichment with moss [NO(3)(-)] variations, suggest the inhibition of moss NRA by RDN. Moreover, isotopic mixing modeling indicated a negligible contribution from NO(3)(-) to moss δ(15)N(bulk) when the RDN/NO(3)(-) reaches 3.8, at which maximum overestimation (21%) of RDN in N deposition can be generated using moss δ(15)N(bulk) as δ(15)N-TDN. Moss δ(15)N-NO(3)(-) can indicate atmospheric NO(3)(-) under distinctly high RDN/NO(3)(-) in deposition, although moss δ(15)N(bulk) can reflect only the RDN therein. These results reveal pitfalls and new mechanisms associated with moss isotope monitoring of N deposition and underscore the importance of biotic N dynamics in biomonitoring studies.
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http://dx.doi.org/10.1021/es300779hDOI Listing
November 2012

Nitrogen and oxygen isotope effects of tissue nitrate associated with nitrate acquisition and utilisation in the moss Hypnum plumaeforme.

Funct Plant Biol 2012 Aug;39(7):598-608

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.

Mosses are effective accumulators and indicators of N deposition, but the mechanisms of moss N utilisation remain unclear. This study monitored nitrate concentrations ([NO3-]) in solutions supplied to Hypnum plumaeforme Wils. to characterise NO3- uptake from rain events. Concentrations and isotopic ratios (δ15N and δ18O) of residual NO3- in moss tissues were measured to interpret induced NO3- reduction. Noninduced NO3- reduction was inferred from endogenous [NO3-] and isotopic variations that occurred during 65 days of N deprivation. H. plumaeforme scavenges NO3- effectively from supplied solutions. The uptake rate increased with substrate [NO3-] (0.4-3.9mgNL-1) and generally obeyed saturation (Michaelis-Menten) kinetics. The uptake rate was maximised within 60min after receiving NO3-, irrespective of the initial substrate [NO3-]. Lower tissue [NO3-] and greater isotopic enrichment verified the inducibility of nitrate reductase activity (NRA) by NO3- availability, but short-term darkness did not markedly influence moss NO3- uptake or reduction. Significant reduction and isotopic enrichment were detected in moss NO3- reserves during N deprivation, showing 15ε of 12.1‰ and 18ε of 14.4‰. The Δδ15N:Δδ18O ratios of ~1: 1 implied that NRA is the single process driving 15N and 18O fractionations. These results provide new isotopic insights into the nitrate reductase dynamics of the moss.
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http://dx.doi.org/10.1071/FP12014DOI Listing
August 2012

Preliminary insights into δ15N and δ18O of nitrate in natural mosses: a new application of the denitrifier method.

Environ Pollut 2012 Mar 10;162:48-55. Epub 2011 Nov 10.

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.

Natural mosses have been employed as reactive and accumulative indicators of atmospheric pollutants. Using the denitrifier method, the concentration, δ(15)N and δ(18)O of moss nitrate (NO(3)(-)) were measured to elucidate the sources of NO(3)(-) trapped in natural mosses. Oven drying at 55-70 °C, not lyophilization, was recommended to dry mosses for NO(3)(-) analyses. An investigation from urban to mountain sites in western Tokyo suggested that moss [NO(3)(-)] can respond to NO(3)(-) availability in different habitats. NO(3)(-) in terricolous mosses showed isotopic ratios as close to those of soil NO(3)(-), reflecting the utilization of soil NO(3)(-). Isotopic signatures of NO(3)(-) in corticolous and epilithic mosses elucidated atmospheric NO(3)(-) sources and strength from the urban (vehicle NO(x) emission) to mountain area (wet-deposition NO(3)(-)). However, mechanisms and isotopic effects of moss NO(3)(-) utilization must be further verified to enable the application of moss NO(3)(-) isotopes for source identification.
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http://dx.doi.org/10.1016/j.envpol.2011.09.029DOI Listing
March 2012

[Expression of ERK1/2 protein in lung tissues of newborn rats with hyperoxia-induced chronic lung disease].

Zhongguo Dang Dai Er Ke Za Zhi 2011 Jul;13(7):581-5

Department of Pediatrics, Shengjing Hospital, China Medical University, Shenyang 110004, China.

Objective: To study the expression of extracellular signal regulated protein kinase (ERK) 1/2 in lung tissues of newborn rats with chronic lung disease (CLD) caused by hyperoxia.

Methods: Forty-eight full-term newborn rats were randomly divided into two groups: hyperoxia and control. The two groups were exposed to a hyperoxic gas mixture (0.90 O(2)) for an induction of CLD and room air within 12 hrs after birth, respectively. The levels of ERK1/2 protein and mRNA in lung tissues were measured using immunohistochemistry, Western blot and real-time PCR methods on postnatal days 3, 7 and 14. The severity of pulmonary fibrosis was evaluated.

Results: The expression of p-ERK protein in lung tissues in the hyperoxia group was significantly higher than that in the control group on postnatal days 7 and 14 (P<0.01). There were no significant differences in the levels of total ERK1/2 protein and ERK1/2 mRNA.

Conclusions: The activation of phosphorated ERK1/2 may lead to lung fibrosis caused by hyperoxia in newborn rats.
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July 2011
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