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Objective:The 97.5th percentile upper reference limit (97.5th URL) of N-terminal prob-type natriuretic peptide (NT-proBNP) is influenced by multiple factors and depends on the inclusion criteria of apparently healthy people. In this study, the reference upper limit of NT-proBNP was established on apparently healthy people in Beijing area with abnormal hs-cTn as the exclusion criterion.Methods:According to the latest expert consensus recommendation standards of natriuretic peptide in the detection and clinical application of heart failure published by the Clinical Application Group of Cardiac Bio-Markers of the International Union of Clinical Chemistry, 1 635 healthy people without abnormal appearance of routine indicators such as sex, age, glycated hemoglobin, estimated glomerular filtration rate and medical history were collected. After excluding participants with potential myocardial injury according to hs-cTnI and/or hs-cTnT concentration>99th URL, NT-proBNP 97.5th URL was established in healthy subjects aged 21-40 years ( n=205), 41-50 years ( n=535), 51-60 years ( n=556) and >60 years ( n=339) based on non-parametric statistics. Results:The level of NT-proBNP was positively correlated with age ( r=0.254, P<0.001). The levels of NT-proBNP were positively correlated with hs-cTnI, hs-cTnT in males ( r=0.377 and r=0.429, both P<0.001). The levels of NT-proBNP were also positively correlated with hs-cTnI, hs-cTnT in females ( r=0.132 and r=0.296, both P<0.001). When hs-cTn>99th URL was used as the criterion to exclude patients with potential myocardial injury, among apparently healthy people aged 21-40 years old, 41-50 years old, 51-60 years old and >60 years old, male NT-proBNP 97.5th URL was 81.9 (90% CI 60.0-588.8), 141.2 (90% CI 100.0-263.6), 272.0 (90% CI 193.0-494.0) and 547.9 (90% CI 311.2-738.6), respectively; For females, the rates were 227.5 (90% CI 81.9-360.8), 153.2 (90% CI 128.2-239.5), 300.6 (90% CI 211.0-376.4) and 395.8 (90% CI 242.3-543.5) ng/L, respectively. Conclusions:This study confirmed that hs-cTn>99th URL can be used as an apparent population screening criterion for natriuretic peptide reference interval studies, which is helpful to remove conventional means to include individuals with occult myocardial injury in apparently healthy patients, so as to establish a more rigorous healthy cohort and establishing solid normal NT-proBNP reference interval.
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Objective:To explore the predictive value of single high-sensitivity cardiac troponin I (hs-cTnI) concentration of 30-day cardiovascular adverse events in patients with suspected acute coronary syndrome (ACS).Methods:This is a multicenter, prospective and observational clinical study. Patients with suspected ACS who were admitted into the emergency department of Fuwai Hospital, the First Affiliated Hospital of Sun Yat-sen University and Nanjing First Hospital from January 2017 to September 2020 were enrolled. hs-cTnI result at the time of visit was obtained from patients with suspected ACS. Patients were followed up for 30 days and patients were divided into no events group and events group according to the presence or absence of 30-day cardiovascular adverse events (acute myocardial infarction (including index), unplanned revascularization and cardiovascular death). The predictive value of single Hs-cTnI at different concentration thresholds on the adverse event was evaluated in terms of sensitivity, negative predictive value (NPV) and 95% confidence interval ( CI). The best threshold was defined as: missed diagnosis rate <2% and NPV >99%. Patients were sub-grouped according to the confounders of hs-cTnI (sex, age, chest pain duration, estimated glomerular filtration rate), and Chi-square test was used to compare sensitivity and NPV among various subgroups. Results:A total of 1 461 patients were included. Among them, 387 patients (26.5%) had 30-day adverse cardiovascular events and 1 074 patients (73.5%) had no adverse cardiovascular events. Mean age was (62±12) years old and 905 were males (61.9%). When the concentration of hs-cTnI was less than 2 ng/L (limit of detection), the missed diagnosis rate of 30-day cardiovascular adverse events was 0.8% (3/387), the sensitivity was 99.2% (95% CI 97.6%-99.8%), and NPV was 98.7% (95% CI 96.0%-99.7%). When hs-cTnI concentration was less than 6 ng/L, the missed diagnosis rate was 1.8%, the sensitivity was 98.2% (95% CI 96.1%-99.2%), and NPV was 99.0% (95% CI 97.9%-99.6%). Subgroup analysis showed that the sensitivity and NPV of single hs-cTnI concentration <6 ng/L for 30-day cardiovascular adverse events were lower in patients with chest pain less than 3 h than those with chest pain time>3 hours ( P<0.05). Conclusions:Single hs-cTnI concentration less than 6 ng/L can predict the risk of 30-day cardiovascular adverse events in suspected ACS patients, but continuous monitoring is recommended for patients with chest pain onset≤3 hours.
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Recently point-of-care testing (POCT) for cardiovascular biomarkers is sharply increasing among subdivision field of POCT,however the relevant quality control is not matched.In this paper,the present situation and problems about selecting biomarkers,managing quality and reporting results during clinical application were expounded.The difference between POCT for cardiovascular biomarkers and routine biomarkers was elaborated.The domestic and international rules and standards about POCT for cardiovascular biomarkers were summarized.Finally,this paper included some rationalization proposal to solve the noticeable problems of quality control in POCT for cardiovascular biomarkers.
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Objective To validate the analytical performance of a cardiac troponin I(cTnI)assay AccuTnI+3 on chemiluminescnet analyzer DXI800 and Access2;and to establish the 99th percentile of cTnI in an apparently healthy Chinese population.Methods The subjects are composed of 1 369 apparently healthy people and 20 acute myocardial infarction(AMI)patients from Wuhan Asian Heart Hospital and Fuwai Hospital from October 2014 to June 2015.The healthy people include 680 males and 689 females;with 340 subjects aged 18-30,674 subjects aged 31-64, and 355 subjects aged ≥65.The detection limits and imprecision of AccuTnI +3 assays were validated according to CLSI EP 15-A2 and EP17-A2 documents;the same samples were analyzed on DXI800 and Access2 to assess the consistency between the two analyzers using Bland Altman plot and Passing-Bablok regression.The correlation between different sample types (lithium heparin plasma, EDTA plasma & serum)were assessed using linear regression analysis.The lithium heparin plasmasamples from 1 369 apparently healthy people were analyzed to calculate the 99th percentile of cTnI.The cTnI concentrations were compared among age and sex groups.The 99th percentile of cTnI were also calculated for each group.The detection rate of cTnI in apparently healthy people was calculated using SPSS23.0.Results The limit of blank(LoB), limit of detection(LoD), and limit of quantification(LoQ)where CV%=10% were 0.007 ng/ml,0.010 ng/ml and 0.016 ng/ml on DXI800;0.008 ng/ml,0.012 ng/ml and 0.026 ng/ml on Access2,respectively.The cTnI measurements on DXI800 and Access2 were consistent and comparable.The cTnI concentrations of lithium heparin plasma, EDTA plasma and serum samples were linearly correlated pairwise: EDTA plasma measuremen t =0.76 heparin plasma measurement, R2=0.999(n=40, P<0.001); serum measuremen t =1.05 heparin plasma measurement,R2=0.996(n=40,P<0.001); serum measuremen t=1.38 EDTA plasma measurement, R2=0.993(n=40,P<0.001).The 99th percentiles were 0.030 ng/ml and 0.035 ng/ml on DXI800 and Access2,respectively,from 1 369 apparently healthy Chinese people.cTnI is significantly higher in elder group than in younger group.The 99th percentiles in 18-30 years old group,31-64 years old group,and≥65 years old group are:0.011 ng/ml,0.029 ng/ml,and 0.035 ng/ml respectively for DXI800;0.023 ng/ml,0.034 ng/ml, and 0.045 ng/ml respectively for Access2.cTnI is significantly higher in men than in women.The 99th percentiles in men and women are: 0.034 ng/ml and 0.032 ng/ml respectively for DXI800;0.043 ng/ml and 0.031 ng/ml respectively for Access2.cTnI was measurable in 62%and 87%of healthy subjects on DXI800 and Access2 systems,respectively.Conclusions The analytical performance of AccuTnI+3 assay fulfills the need of clinical use and the criteria of high-sensitive cardiac troponin assay.
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ObjectiveTo explore the effects of vector fusion peptides on the conformation and immune reactivity of recombinant polyepitope antigens,M.RCAg-1.MethodsWe subcloned polyepitope artificial antigen gene,M.RCAg-1,into prokaryotic expression vectors,pDS-ex,that contain different fusion tags at the N-terminus or no any tag by different restriction enzyme cutting site.Three recombinant proteins expressed by these vectors,named P312-1,P312-2,and P312-3,were purified and purity is greater than 95％.Then BALB/c mice were vaccinated with the three proteins formulated with Freund's adjuvant through intranasal.Serum were collected to detect specific antibodies of M.RCAg-1 and individual epitope by ELISA ; natural parasite antigen was recognized by indirect immunofluorescence assay; mouse specific T lymphocyte activation was detected by enzyme-linked immunosorbent spot test (ELISPOT) ; and the growth of Plasmodium falciparum in vitro to evaluate by growth inhibition assay(GIA),and analyze secondary and tertiary structures of recombinant proteins from different expression vectors by bioinformatics and circular dichroism technique.ResultsThe P312-1,P312-2 have almost the same amino acid sequence,and the three proteins have the same immunogenicity in animal models(P＞0.05),however,the different proteins elicited various T-cell responses,the rabbit antibody induced by these proteins showed diverse efficacy in malaria parasite growth inhibition assaysin vitro ( respectively,93.9％,14.7％,54.3％ ).The significant differences of secondary and tertiary structures were shown in recombinant proteins from different expression vectors,analyzed by bioinformatics and circular dichroism technique,which demonstrated the change of protein molecule spaces conformation,and the obviously change of some epitope locations.ConclusionThese results suggest that the expressed polyepitope artificial antigens originating from the different vector fusion peptides indeed affect the protein folding and,subsequently,the epitope exposure.Thus,these proteins are able to induce both distinct humoral and cellular immune responses in animal models,and they affect the efficacy of immune inhibition against the parasite,the enhancement or suppresses.
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ObjectiveTo detect the difference of cytokines and antibodies productions by immunologic system from mice and rabbits vaccinated with the M.RCAg-1 chimeric protein,expressed in E.coli,formulation with different adjuvants,including Freund's adjuvant and three clinically acceptable adjuvants,namely,Al(OH)3,Montanide ISA720 and Montanide ISA51.MethodsSix weeks female BALB/c mice were vaccinated with recombinant protein formulated with different adjuvants through intranasal.Serum were collected to detect specific antibodies of M.RCAg-1 and individual Epitope by ELISA ; natural parasite antigen was recognized by indirect immunofluorescence assay; mouse specific T lymphocyte activation was detected by enzyme-linked immunosorbent spot test (ELISPOT) ; Affinity assay between protein and immune IgG of rabbits with the biosensor,and the growth of Plasmodiumfalciparum in vitro to evaluate by growth inhibition assay(GIA).ResultsDifferent formulation can induce different levels of antibody titers,the effection of ISA51 adjuvant was most closely with Freund's adjuvant,and can induce a higher specific antibody of 11 epitopes within proteins,can effectively stimulate cellular immune response based on the IFN-γ,to avidity Montanide ISA51 adjuvant immune antibodies and M.RCAg-1 protein affinity than the other two adjuvants;and Montanide ISA720 adjuvants and Al (OH)3 adjuvant group in mice can't induce a significant IFN-γresponse(P＞0.05).On avidity assay,the Montanide ISA51 formulation group was better than the other two adjuvants; and Montanide ISA720 and Al (OH)3 adjuvant formulation group can't induce a significant IFN-γresponse in mice(P＞0.05) ; the inhibition rates were 60% and 100% in 3D7 and Dd2 Plasmodium falciparum at a concentration of 2 mg/ml IgG by Montanide ISA51 formulated protein,and IgG of Al( OH)3 formulation could not effectively inhibit the in vitro growth of Plasmodium falciparum( 10% ),while IgG of Montanide ISA720 formulation could not inhibit growth of parasite in vitro.ConclusionBy comparing three clinically acceptable adjuvants and Freund's adjuvant in BALB/c mice and New Zealand rabbit,Montanide ISA51 adjuvants can be acceptable formulated M.RCAg-1 protein induced humoral and cellular immune responses,can be used as one of the candidate adjuvants.
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Objective To study the effect of long-term salmon calcitonin on bone mineral density (BMD), bone metabolism biochemical indicators and subjective score of bone pain in maintenance hemedialysis (MHD) patients with osteopenia. Methods Thirty-four MHD patients diagnosed as osteopenia by dual-energy X-ray absorptiometry (DXEA) were enrolled in this study. All the patients were treated with hypodermic injection of salmon calcitonin (50 U, thrice a week) for 12 months. The detecting parameters were as follows: BMD with DEXA in lumbar spine (L1-L4), femoral neck, troch, inter, and Ward's triangle before and after the study;serum bone metabolism biochemical indicators before and 6 and 12 months after the study;subjective scores of bone pain before and 1, 6, and 12 months after the study. Results Thirty-two patients were followed-up successfully. As compared to BMD parameters before study, the total T-score (-1.98± 2.20 vs 1.26±1.88, P=0.009) and total Z-score (-0.90±2.15 vs 0.08±2.05, P=0.002) of lumbar spine, the total T-score (-1.72±1.53 vs 1.06±1.58, P=0.016) and totle Z-score (-0.66±0.80 vs 0.08±1.08, P=0.029) of hip, the T-score of L3 (-2.02±2.51 vs 1.24±2.02, P=0.033), the Z-score of L2 (-0.44±1.82 vs 0.06±1.63, P=0.016), the Z-score of femoral troch (-0.65±1.11 vs 0.48±1.12, P=0.034) and the Z-score of inter (-0.58±0.94 vs 0.02±1.12, P=0.006) were increased significantly after study. But there were no significant differences in other examined regions and serum biochemical parameters. The subjective scores of bone pain were decreased rapidly for 41.7% after 1 month (P<0.01) and 76.6% after 6 months (P<0.01). The subjective score of bone pain after 12 months was similar to 6 months. The side effects of salmon calcitonin included nausea and vomitting in 5 cases (14.71%, 5/34), dizziness, blushing and flustered in 1 case respectively (3.13%,1/32). Conclusions Long-term hypodermic injection of salmon calcitonin can improve BMD and bone pain for MHD patients with osteopenia but has no significant effect on serum bone metabolism biochemical indicators. Salmon calcitonin is safe for MHD patients with seldom side effects, such as nausea and vomitting.