Validation of Prosthetic Mitral Regurgitation Quantification Using Novel Angiographic Platform by Mock Circulation

ObjectivesThis study aimed to validate a dedicated software for quantitative videodensitometric angiographic assessment of mitral regurgitation (QMR).BackgroundQuantitative videodensitometric aortography of aortic regurgitation using the time-density principle is a well-documented technique, but the angiographic assessment of mitral regurgitation (MR) remains at best semi-quantitative and operator dependent.MethodsFourteen sheep underwent surgical mitral valve replacement using 2 different prostheses. Pre-sacrifice left ventriculograms were used to assess MR fraction (MRF) using QMR and MR volume (MRV). In an independent core lab, the CAAS QMR 0.1 was used for QMR analysis. In vitro MRF and MRV were assessed in a mock circulation at a comparable cardiac output to the in vivo one by thermodilution. The correlations and agreements of in vitro and in vivo MRF, MRV, and interobserver reproducibility for QMR analysis were assessed using the averaged cardiac cycles (CCs).ResultsIn vivo derived MRF by QMR strongly correlated with in vitro derived MRF, regardless of the number of the CCs analyzed (best correlation: 3 CCs y = 0.446 + 0.994x; R = 0.784; p =0.002). The mean absolute difference between in vitro derived MRF and in vivo derived MRF from 3 CCs was 0.01 ± 4.2% on Bland-Altman analysis. In vitro MRV and in vivo MRV from 3 CCs were very strongly correlated (y = 0.196 + 1.255x; R = 0.839; p < 0.001). The mean absolute difference between in vitro MRV and in vivo MRV from 3 CCs was –1.4 ± 1.9 ml. There were very strong correlations of in vivo MRF between 2 independent analysts, regardless of the number of the CCs.ConclusionsIn vivo MRF using the novel software is feasible, accurate, and highly reproducible. These promising results have led us to initiate the first human feasibility study comprising patients undergoing percutaneous mitral valve edge-to-edge repair.     

Re-evaluation of serum alanine aminotransferase upper normal limit and its modulating factors in a large-scale population study.

BACKGROUND: The upper normal limit (ULN) of serum alanine-aminotrasferase (ALT) normal range was recently challenged, because patients diagnosed with liver diseases may have 'normal' or near-'normal' ALT levels, and because possible modulators are often ignored in determining normal range. AIM: To estimate the ULN for serum ALT and to identify factors modulating it. SUBJECTS AND METHODS: We reviewed medical records of subjects aged 15-90, who underwent standard panels of laboratory tests, including serum ALT, over 6 months at a central laboratory. Three groups were defined: Group 1, comprised total study population (N=272 273). Group 2 (N=87 020) comprised total study population, excluding those receiving potentially hepatotoxic drugs, or diagnosed with liver disease, or had any abnormal laboratory test results other than for triglycerides, cholesterol, glucose, or HbA1c. Group 3 (N=17 496) the 'healthy' population, from whose ALT values we established the new ULN, comprised Group 2 subjects with normal triglycerides, cholesterol, glucose, and HbA1c levels. RESULTS: The 95th percentile ALT values, corresponding to the ULN, in groups 1, 2, and 3 were 50.1, 40, and 37.5 U/l, respectively. 6.2% (16 943/273 273) of subjects whose ALT was below ULN listed by the test manufacturer (52 U/l), had ALT level above our new ULN. Linear and logistic-regression analyses showed that ALT levels were significantly modified by gender, age, glucose, cholesterol, triglycerides, and overweight/obesity diagnosis. Significant interaction was found between gender, glucose and cholesterol levels. CONCLUSIONS: In this first large-scale study of 'healthy' population, serum ALT ULN was far lower than currently accepted value. Age and gender may be considered when determining the ULN for ALT.     

用实时荧光定量PCR选择急性呼吸窘迫综合征患者血清microRNA内参照基因

目的探讨用实时荧光定量PCR检测急性呼吸窘迫综合征(ARDS)患者血清微小RNA(microRNA,miRNA)的表达并选择最优内参照基因。方法用实时荧光定量PCR检测40例ARDS患者及20例体检健康者血清中5个miRNA候选内参照基因miR-16-5p、miR-93-5p、miR-101-3p、miR-191-5p和U6,并用ge Norm法、Norm Finder法、bestkeeper法和相对△Ct法4种算法分析内参照基因稳定性,通过对4种算法稳定值进行排序并计算几何均数的方法分析综合稳定值。结果比较5个候选内参照基因在ARDS患者和体检健康者的表达水平,差异均无统计学意义(P均0.05)。4种算法综合分析显示,miR-16-5p以最小的稳定值1.32成为综合稳定性最高的内参照基因,其次是miR-101-3p、U6、miR-93-5p和miR-191-5p。结论实时荧光定量PCR法确定ARDS患者血清miRNA最优的内参照基因为miR-16-5p。     

Hot topics in coagulation testing: Important considerations for testing children for bleeding/thrombotic disorders

The accurate use and interpretation of diagnostic investigations are essential for safe and effective patient care. Appropriate application and interpretation of coagulation testing can be challenging, and many controversies exist relating to the standardization of testing procedures, the application of relevant tests to different patient populations and the interpretation of test results. We present a list of the most prominent controversies in coagulation testing and have selected three specific examples (age‐appropriate reference ranges, therapeutic anticoagulation monitoring and tests of thrombin generation) for closer discussion, highlighting examples with a paediatric framework. We discuss the limitations of discrete age‐partitioned reference intervals, given the established principle of developmental haemostasis; the difficulties in establishing normative data across different laboratories; important pre‐analytical variables affecting coagulation testing; the challenges in interpreting APTT and anti‐Xa assays for monitoring unfractionated heparin therapy in different clinical situations; and the limitations in interpreting tests of thrombin generation due to current available thrombin‐specific substrates and the complicating factor of variable alpha2‐macroglobulin levels. These controversies are demonstrated using paediatric examples, but raise important implications for coagulation testing in patients of all ages and highlight the pressing need for further research in these areas.     

Comparison of gluten recovery in gluten-incurred buckwheat flour using different commercial test kits

Recovery of gluten in buckwheat flour was evaluated as part of an effort to produce wheat-contaminated buckwheat flours that could be used as reference materials (RMs) for testing the presence of gluten in buckwheat. RMs of buckwheat containing 0, 20, 100 and 1000 ppm gluten were created and tested by ELISA. The Gluten-Check kit detected gluten accurately at all levels; RIDASCREEN and Biokits tests were accurate at 20 and 100 ppm levels, but at 1000 ppm both suffered from extraction saturation effect; Veratox kit read 60% higher for the 20 ppm RM (i.e., 31.9 ppm), but close to the target at 100 ppm RM; Veratox R5 kit showed low accuracy with around 30% recovery at 20 and 100 ppm and some 60% at 1000 ppm level. Overall, the results showed variations in recovery among different test kits which could have important implications in the accurate detection of gluten in buckwheat.     

Production of certified reference materials for the sports doping control of the REV‐ERB agonist SR9009

Two human metabolites of the REV‐ERB agonist SR9009, identified by researchers with an interest in sports doping control, have been synthesized and assessed for purity. The synthesis employed was a modification of published procedures for the parent SR9009, careful attention to the purification of intermediates and the final product ensuring materials of the highest purity were available for certification. For each candidate material impurities of related structure were identified and quantified as a relative mass fraction using high performance liquid chromatography–ultraviolet (HPLC–UV) detection and proton nuclear magnetic resonance (¹H NMR) spectroscopy. The quantification of water, occluded solvent, and inorganic residue was assessed using Karl Fischer, ¹H NMR, and thermogravimetric analysis, thereby completing the assessment of all impurities typically characterized by the mass balance approach. Summation and subtraction from 1000 mg/g afforded the mass fraction of the main component, the associated uncertainty ensuring certified reference material status can be applied to the resulting pure substance calibration standards. The availability of these standards to the sports doping control community will facilitate delivery of metrological traceability to the SI unit for mass (kg) to routine testing results and aid method development for the detection and quantification of SR9009 abuse.