Continuous Flow-Double Purge and Trap Method for Preconcentrating Mercury in Large Volumes of Seawater for Stable Isotope Analysis.

Mercury (Hg) isotopes provide a useful tool to understand Hg sources and processes in the environment. The Hg isotopic composition of seawater remains poorly constrained due to the lack of an efficient method to process large volumes of low-Hg-concentration seawater samples. Here, we develop a continuous flow-double purge and trap device for the in situ preconcentration of Hg in seawater. This method yielded a good Hg recovery of 91.7 ± 3.3% (n = 4, 1SD) for spiked seawater samples and gave reasonably similar Hg isotope ratios of NIST 8610, indicating a limited matrix effect and limited Hg isotope fractionation during processing of seawater. NIST 8610 δ202Hg (-0.55 ± 0.09‰, n = 4, 1SD) and Δ199Hg (0.07 ± 0.02‰, n = 4, 1SD) were similar to previously published data. The method was successfully applied to seawater collected from the Xiamen Bay and the South China Sea. The seawater samples showed a Hg recovery of 91.6 ± 5.4% (n = 12, 1SD). Seawater Δ199Hg (-0.04 ± 0.05‰, n = 7, 1SD) in the Xiamen Bay was different from seawater Δ199Hg (0.05 ± 0.07‰, n = 5, 1SD) in the South China Sea, which implies distinct Hg sources to coastal and open ocean areas and highlights the robustness of our method in understanding the Hg isotopic composition of seawater.

Evolocumab prevents atrial fibrillation in rheumatoid arthritis rats through restraint of PCSK9 induced atrial remodeling.

INTRODUCTION: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is implicated in the pathogenesis and progression of autoimmune disease. Patients with rheumatoid arthritis (RA) are at high risk of developing atrial fibrillation (AF), while whether PCSK9 is involved in the onset of AF among RA patients remains unclear. OBJECTIVES: To explore the role of PCSK9 in the occurrence of AF in RA patients and decipher the underlying mechanism. METHODS: We established a rat model of collagen-induced arthritis (CIA) by immunization with type II collagen in Freund's incomplete adjuvant. Atrial electrophysiological test was used to evaluate AF susceptibility. We performed a clinical study to examine the correlation between PCSK9 level and AF, which recruited healthy control, RA patients and RA patients complicated with AF. Evolocumab (a monoclonal antibody of PCSK9) is administered via intraperitoneal injection in CIA rats to assess the role of PCSK9 in RA-related AF. LPS-RS (LPS inhibitor), clodronate liposomes (depletion of macrophages), and cell co-culture model were used to dissect the mechanism underlying PCSK9 promotes AF. RESULTS: AF inducibility and duration were higher in CIA rats, accompanied by elevated plasma and atrial PCSK9. Interestingly, compared with healthy control subjects, patients with RA showed an increase in PCSK9, and the PCSK9 is much higher in RA patients complicated with AF. The level of PCSK9 was independently associated with AF risk in RA patients. In the in vivo experiment, evolocumab reduced AF susceptibility, and ameliorated atrial structural remodeling of CIA rats. Mechanistically, augmented LPS in CIA rats led to an increase in PCSK9, which exacerbated fibrosis of cardiac fibroblasts and apoptosis of cardiac myocytes by enhancement of M1 macrophages polarization and inflammation, thereby contributing to AF. CONCLUSION: This study suggests that elevated PCSK9 causes atrial structural remodeling by enhancement of M1 macrophages polarization in atria, and evolocumab can effectively protects CIA rats from AF.

Effects of ticagrelor monotherapy vs. clopidogrel monotherapy on platelet reactivity: a randomized, crossover clinical study (SINGLE study).

Increasing clinical trials demonstrated that the discontinuation of aspirin while maintaining a P2Y12 inhibitor monotherapy could decrease the risk of bleeding without losing the antithrombotic effect. However, no data are available on the platelet reactivity of patients undergoing ticagrelor monotherapy vs. clopidogrel. Therefore, we performed this study to observe the efficacy of ticagrelor monotherapy vs. clopidogrel in Chinese patients with chronic coronary syndrome. This randomized, single-blinded, crossover trial enrolled 50 patients who were administered with ticagrelor (90 mg twice daily for 2 weeks) or clopidogrel (75 mg once daily for 2 weeks). Followed by a 2-week washout period, the two groups of patients underwent a crossover trial. Light transmission aggregometry (LTA) and thromboelastography (TEG) assays were used to test platelet reactivity. The platelet aggregation rate (PAgR) of ADP and AA was significantly lower with ticagrelor than clopidogrel (PAgR of ADP, 27.30% (7.30%-42.635%) vs. 35.55% (12.03%-69.25%), P = .0254; PAgR of AA, 77.80% (21.60%-86.43%) vs. 83.10% (67.13%-87.20%), P = .0400). There was no significant difference in PAgR of collagen and epinephrine between the two groups. The TEG assay showed that ADP and AA, which induced the inhibition of platelet aggregation, were significantly higher in the ticagrelor group than those in the clopidogrel group [ADP%, 69.00% (59.68%-88.95%) vs. 60.55% (35.98%-78.35%), P = .0020; AA%, 53.65% (22.75%-79.28%) vs. 15.15% (5.75%-70.25%), P = .0127]. High on-treatment platelet reactivity (HTPR) on ADP was 2.17% with ticagrelor and 19.57% with clopidogrel. HTPR on AA was 50.00% with ticagrelor and 69.57% with clopidogrel. Ticagrelor and clopidogrel caused the inhibition of ADP and AA-induced platelet aggregation. Moreover, ticagrelor monotherapy had a stronger inhibitory effect than clopidogrel monotherapy (except on collagen and epinephrine).

Efficacy and safety of different ticagrelor regimens versus clopidogrel in patients with coronary artery disease: a retrospective multicenter study (SUPERIOR).

Current guidelines favor dual anti-platelet therapy with ticagrelor 90 mg BID (T90BID) over clopidogrel 75 mg QD (C75QD) in addition to aspirin for acute coronary syndrome. However, an increased risk of ticagrelor-related adverse events prompted the evaluation of low-dose regimens. This study (NCT03381742) retrospectively analyzed the data from 11 hospitals on 3,043 patients with coronary artery disease, who received C75QD, T90BID, ticagrelor 45 mg BID (T45BID), or ticagrelor 90 mg QD (T90QD). Compared with C75QD, both T45BID and T90QD showed significantly higher inhibition of platelet aggregation (P < .0001) and lower platelet-fibrin clot strength (P < .0001) induced by adenosine diphosphate. Furthermore, compared with T90BID, two low-dose regimens had a much lower minor bleeding rate and a significantly higher proportion of patients within the therapeutic window for P2Y12 receptor reactivity. There were no significant differences between T45BID and T90QD in the trough plasma concentrations of ticagrelor and its active metabolite. Similar efficacy and safety outcomes were observed in the propensity score-matched analysis. In conclusion, the low-dose ticagrelor regimen, either T45BID or T90QD, may provide a more attractive benefit-risk profile than C75QD or T90BID.

Hydroxychloroquine use and progression or prognosis of COVID-19: a systematic review and meta-analysis.

Hydroxychloroquine (HCQ) has been implicated in antiviral activity in vitro against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, there is still controversy about whether HCQ should be used for coronavirus disease 2019 (COVID-19) patients due to the conflicting results in different clinical trials. To systematically assess the benefits and harms of HCQ for the treatment of COVID-19. Data sources were systematically searched from Pubmed, Biorxiv, ChiCTR, Clinicalrials.gov , and the Cochrane library of RCTs for studies published from inception to June 1, 2020, to obtain any possible inclusion. This meta-analysis of inclusion criteria was directed on the basis of the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P). Pooled studies by the title and abstract were screened and removed in the light of meta-analysis by two reviewers. Seven studies involving 851 participants with COVID-19 were eligible for analysis. There was no significant difference in RT-PCR negative conversion between HCQ group and standard treatment (ST) group (RR = 1.11, 95% CI = 0.77-1.59, P = 0.591). The rate of exacerbated pneumonia on chest CT in HCQ group was lower than that in ST group (RR = 0.44, 95% CI = 0.20-0.94, P = 0.035). There was no statistical difference in progressed illness between the HCQ group and the ST group (RR = 0.66, 95% CI = 0.18-2.43, P = 0.530). Death (RR = 1.92, 95% CI = 1.26-2.93, P = 0.003) was distinctly different in HCQ group compared with ST group in the treatment of COVID-19. Our meta-analysis demonstrated that there was no robust evidence to support prescribing HCQ as a treatment for COVID-19.

Effects of doxazosin mesylate versus nifedipine on blood pressure variability in hypertensive patients: a randomized crossover study (SIMILAR).

OBJECTIVE: Blood pressure variability (BPV) is a powerful predictor of end-organ damage, cardiovascular events and mortality independently of the BP level. Calcium channel blockers may offer an advantage over other first-line antihypertensive drugs by preventing increased BPV. But the effect of alpha-receptor blockers on BPV in hypertensive patients is still unclear. METHODS: In this crossover trial, 36 hypertensive patients were randomly assigned to two groups, receiving doxazosin mesylate gastrointestinal therapeutic system (GITS) (4 mg/day) or nifedipine GITS (30 mg/day) for 12 weeks, followed by a 2-week washout period then a 12-week crossover phase. At baseline and after 12-week treatment, 24-hour ambulatory BP monitoring was performed. BPV was evaluated through standard deviation (SD), coefficient of variation (CV), and average real variability (ARV) of systolic BP (SBP) and diastolic BP (DBP) during daytime, nighttime and over 24 hours. RESULTS: After 12-week treatment, both doxazosin and nifedipine significantly decreased SBP and DBP (P < 0.05), whereas no between-group differences were shown (P>0.05). Systolic BPV (24-hour SD, CV, and ARV; daytime SD; nighttime SD and CV) and diastolic BPV (24-hour SD and ARV) were significantly lowered by nifedipine (P < 0.05); doxazosin resulted in significant reductions of systolic BPV (24-hour SD, CV and ARV; daytime SD; nighttime SD) and diastolic BPV (nighttime SD and CV) (P < 0.05). Doxazosin was revealed to be as effective as nifedipine for reducing BPV (P > 0.05) except for 24-hour SBP ARV. CONCLUSIONS: Doxazosin mesylate GITS had similar therapeutic effects on BP, BP SD, and BP CV lowering as nifedipine GITS in patients with mild-to-moderate essential hypertension.

Effects of different doses of ticagrelor on platelet aggregation and endothelial function in diabetic patients with stable coronary artery disease.

We performed this study to observe the effects of different doses of ticagrelor and standard-dose clopidogrel on platelet reactivity and endothelial function in diabetic patients with stable coronary artery disease (CAD). Sixty type 2 diabetic patients were assigned to one-quarter standard-dose ticagrelor, half standard-dose ticagrelor, standard-dose ticagrelor and standard-dose clopidogrel groups. Light transmission aggregometry (LTA) and VerifyNow assay were used to measure platelet function. Endothelial function was assessed by measurement of flow-mediated vasodilation (FMD) and plasma von Willebrand factor (VWF) levels were detected. Enzyme-linked immunosorbent assay (ELISA) examined the Interleukin-8(IL-8) and IL-10. The results suggested that the one-quarter dose (34.0%± 14.7%), half-dose (26.9%± 11.6%) and standard-dose (17.3%± 10.3%) ticagrelor showed lower platelet aggregation rate than clopidogrel (52.8%± 18.3%; P ï¼œ0.0001). PRU values in three ticagrelor groups were lower than that in clopidogrel group (102 (76-184)；75 (33-88)；38 (11-52) versus 194 (138-271) and；P ï¼œ0.0001). FMD levels were higher in ticagrelor groups compared with baseline levels while lower in clopidogrel group after treatment. However, no significant differences were found in the percentage increase in the FMD between ticagrelor groups and clopidogrel group. The levels of VWF after treatment were lower than the baseline levels, but there was no statistically significant difference between ticagrelor group and clopidogrel group after treatment. The concentration of IL-8 and IL-10 were decreased in patients with half and standard-dose ticagrelor group. In conclusion, one-quarter standard-dose ticagrelor produced similar inhibitory effects on platelet aggregation as standard-dose clopidogrel in diabetic patients with stable CAD. The half standard-dose ticagrelor had a similar inhibitory effect on platelet inhibition as standard-dose ticagrelor, which was stronger than that of clopidogrel. Moreover, the half-dose ticagrelor had equal protection of endothelial function and inhibition of inflammatory factor as standard-dose ticagrelor.

Metoprolol has a similar therapeutic effect as amlodipine on BP lowering in hypertensive patients with obstructive sleep apnea.

PURPOSE: ß-Blocker use has been controversial for a long time in the management of hypertensive patients with obstructive sleep apnea (OSA). The aim of present study was to compare the effects of metoprolol on BP lowering with amlodipine in hypertensive OSA patients. METHODS: Hypertensive subjects with OSA were randomly assigned to metoprolol and amlodipine groups, receiving 12 weeks of oral either metoprolol (47.5 mg once daily) or amlodipine (5 mg once daily) treatment. At baseline and after the 12-week treatment period, 24-h ambulatory blood pressure monitoring was performed in both groups. RESULTS: Both of metoprolol and amlodipine treatments significantly lowered 24-h blood pressure (BP) (from 143/88 to 132.3/81.6 mmHg; from 141.3/84.5 to 133.7/80.8 mmHg), daytime BP (from 146/90.2 to 136.4/84.6 mmHg; from 145.1/87.6 to 138.2/84.1 mmHg), and nighttime BP (from 139.1/83.9 to 125.7/76.2 mmHg; from 134.5/78.5 to 125.8/74.1 mmHg) (all P < 0.05). But there were no significant differences between the groups in BP variability (P > 0.05). Besides, metoprolol significantly reduced daytime heart rate (HR) (P < 0.05), while 24-h and nighttime HR values had no remarkable changes compared with baseline (P > 0.05). CONCLUSIONS: Metoprolol had similar therapeutic effects on BP lowering as amlodipine and could not decrease HR during the nighttime in hypertensive patients with OSA.

One-quarter standard-dose ticagrelor better than standard-dose clopidogrel in Chinese patients with stable coronary artery disease: A randomized, single-blind, crossover clinical study.

BACKGROUND: Ticagrelor has been demonstrated to provide a more rapid and powerful inhibition of platelet aggregation compared with clopidogrel in coronary artery disease (CAD) patients. In our previous study, we found that half-dose ticagrelor produced similar inhibitory effects on platelet aggregation as standard-dose ticagrelor and exerted significantly stronger effects than clopidogrel in Chinese patients with non-ST-elevation ACS. Therefore, we performed this study to observe the efficacy of one-quarter standard-dose ticagrelor in comparison to standard-dose clopidogrel in Chinese patients with stable CAD. METHODS: In a randomized, single-blind, crossover trial, 30 patients with stable CAD were randomized to one-quarter standard-dose ticagrelor (22.5mg BID for 7days) or standard-dose clopidogrel (75mg QD for 7days). Following a 2-week washout period, patients switched regimens. Light transmission aggregometry (LTA) and VerifyNow assay were used to measure platelet function. RESULTS: The platelet aggregation rate (PAgR) was obviously lower with ticagrelor than clopidogrel (17.70%±12.67% versus 27.63%±13.10%, P<0.05). The % inhibition levels in the ticagrelor group exhibited significantly greater than that in the clopidogrel group (65.33%±21.31% versus 36.23%±23.01%, P<0.01). PRU values in the ticagrelor group were dramatically lower than that in the clopidogrel group (87.03±51.38 versus 163.77±58.66, P<0.01). High-platelet reactivity (HPR) (≥208 PRU) was 0% with ticagrelor and 16.67% with clopidogrel. CONCLUSIONS: One-quarter standard-dose ticagrelor provided greater degree of platelet inhibition than standard-dose clopidogrel in Chinese patients with stable CAD.

Plasma microRNAs as potential noninvasive biomarkers for in-stent restenosis.

OBJECTIVE: To investigate whether microRNAs (miRs) can serve as novel biomarkers for in-stent restenosis (ISR). METHODS: This retrospective, observational single-centre study was conducted at the cardiovascular department of a tertiary hospital centre in the north of China. Follow-up coronary angiography at 6 to 12 months was performed in 181 consecutive patients implanted with drug-eluting stents. Fifty-two healthy volunteers served as the control group. The plasma miRs levels were analyzed by quantitative real-time PCR. Receiver-operating characteristic curve (ROC) analysis was performed to investigate the characters of these miRs as potential biomarkers of ISR. RESULTS: MiR-21 levels in ISR patients were significantly higher than those in non-ISR patients and healthy controls (P<0.05), while miR-100 (P<0.05), miR-143 (P<0.001) and miR-145 (P<0.0001) levels were significantly decreased in ISR patients. Further analysis showed that miR-21 levels were remarkably increased (P = 0.045), while miR-100 (P = 0.041), miR-143 (P = 0.029) and miR-145 (P<0.01) levels were dramatically decreased in patients with diffuse ISR compared to those with focal ISR. ROC analysis demonstrated that the area under curve of miR-145, miR-143, miR-100 and miR-21 were 0.880 (95% confidence interval; CI = 0.791-0.987, P<0.001), 0.818 (95% confidence interval; CI = 0.755-0.963, P<0.001), 0.608 (95% confidence interval; CI = 0.372-0.757, P<0.05) and 0.568 (95% confidence interval; CI = 0.372-0.757, P<0.05), with specificity of 83.1%, 80.1%, 68.9% and 68.6%, and sensitivity of 88.7%, 82.1%, 60.2% and 50.1%, respectively. CONCLUSIONS: Circulating miR-143 and miR-145 levels are associated with the occurrence of ISR and can serve as novel noninvasive biomarkers for ISR.