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Objectives:To establish a candidate reference method of isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) for the determination of human plasma normetanephrine, and to evaluate the performance of the method. The method was used to quantify the samples of the external quality assessment program, and to initially evaluate the detection status of plasma normetanephrine.Methods:The isotope standard solution of normetanephrine was selected as the internal standard, the gravimetric method was used for sampling, and the standard curve method was used for quantification. Protein precipitation combined with weak cation solid phase extraction was used for pretreatment, and ultra-high liquid chromatography-coupled triple quadrupole mass spectrometry was used for LC/MS analysis. According to the relevant EP documents, the specificity, matrix effect, detection limit, quantification limit, precision, accuracy, and uncertainty of the method were estimated. This method is used to quantify the samples of the 2020 National Center for Clinical Laboratories external quality assessment program of normetanephrine. Taking the average value of this method as the target value, the optimal allowable total error standard of biological variation as the evaluation limit, the quality of the laboratory testing was evaluated.Results:The method had good specificity, and the interferences and matrix effects did not affect the detection results. The detection limit and quantification limit of plasma normetanephrine were 1.08 pg/g and 3.54 pg/g, respectively. The intra-batch coefficient of variation ( CV) and total CV were 0.43%-1.10% and 0.61%-1.42%, respectively. The relative recovery rates were 98.5%～101.9%. The relative expansion uncertainty of the four plasma samples were 3.10%, 2.34%, 2.16%, and 1.73%, respectively. The results of the external quality assessment program showed that the pass rates of the 202013 and 202014 samples were 80% and 85%, respectively. Conclusions:The study established a candidate reference method of ID-LC/MS/MS for the measurement of plasma normetanephrine. The method is accurate, precise and simple, and is expected to be used as a reference method for the determination of plasma normetanephrine, and can be applied to quantify the samples of the external quality assessment program.
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OBJECTIVE：To study the effects of rat intestinal flora on the pharmacokinetic parameters of pyrazinamide and its active metabolite pyrazinoic acid. METHODS ：Totally 16 SD rats were randomly divided into trial group and control group ，with 8 rats in each group. Trial group was given mixed antibiotics （streptomycin sulfate+neomycin sulfate ）intragastrically to construct pseudoaseptic rat model. After modeling ，both groups were given pyrazinamide intragastrically （150 mg/kg）. Before and 0.167， 0.333，0.667，1，1.5，2，3，4，6，9 h after administration ，0.1 mL blood sample was collected from orbital venous plexus ，and 0.3 mL blood sample was collected from orbital venous plexus 12，24 h after administration. Using phenacetin as internal standard ， LC-MS/MS method was adopted to determine the plasma concentration of pyrazinamide and pyrazinoic acid. The determination was performed on Agilent ZORBAX SB-Aq column with mobile phase consisted of 0.2％ formic acid （containing 8 mmol/L ammonium acetate）-methanol（gradient elution ）at the flow rate of 1 mL/min. The column temperature was set at 30 ℃，and sample size was 10 μL. The ion source was ESI and the temperature of ion source was 500 ℃. The collision gas was nitrogen and the pressure was 10 psi. The temperature of mass transfer interface was 100 ℃. The mass spectrum monitoring mode was multi reaction monitoring ， and the collection mode was positive ion mode. The monitoring transition ion-pairs were m/z 124.0→79.0（pyrazinamide），m/z 125.1→79.1（pyrazinic acid ）and m/z 180.0→110.2（internal standard ）. The de-clustering potential and collision voltage were 55， 26 and 85 V，24，23 and 28 V，respectively. The pharmacokinetic parameters were calculated and compared by using DAS 2.1.1 software. RESULTS ：The linear ranges of pyrazinamide and pyrazinoic acid were 25-5 000 ng/mL（r＝0.997 6）and 100-12 500 ng/mL（r＝0.999 0）. The lower limits of quantification were 25 and 100 ng/mL，respectively. Intra-batch and inter-batch accuracy were 92.93％-100.50％，and RSDs of intra-batch and inter-batch precision and matrix effect tests were all lower than or equal to 8.42％（n＝6 or n＝3）. Compared with control group ，tmax of pyrazinamide in trial group was prolonged significantly （P＜0.01）； there was no statistical significance in other pharmacokinetic parameters between 2 groups（P＞0.05）. CONCLUSIONS ：The absorption of single dose pyrazinamide is delayed with the change of intestinal flora in rats.
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Objective:To evaluate the performance of aldosterone testing in China through the External Quality Assessment (EQA) and improve the testing quality of aldosterone.Methods:Two kinds of EQA program for aldosterone were carried out in China, one of which is Routine EQA and the other is Trueness verification scheme. Lyophilized sera with 5 concentration levels were used as quality control of Routine EQA. The results were grouped according to the instrument. Target values and the coefficient of variation ( CV) were calculated in each group. Trueness verification scheme was verified by using frozen human sera of 3 concentration levels determined by the reference method, and the bias of each instrument group from the target value was calculated. Results:272 laboratories submitted the testing results, and 91.6% of laboratories used chemiluminescence method. The maximum CV was obtained by radioimmunoassay and liquid chromatography mass spectrometry, and the robust CVs were 14.6%-33.4% and 43.5%-53.9%, respectively. For chemiluminescence methods, the robust group CV was less than 10%. The results of the Trueness verification scheme showed that liquid chromatography mass spectrometry method was the most accurate method, with biases of -7.9%, 8.9% and -0.7% for the three quality controls. Diasorin system had the more accurate results deviated from the target by 58.7%, 7.9% and -2.1%, respectively. The results of other chemiluminescence methods were negatively correlated with the sample concentration, and one of them with a bias of 479%. Conclusions:The accuracy and comparability of aldosterone among laboratories in China are not satisfactory. Reagent manufacturers and laboratories should pay more attention to EQA, with the aldosterone results traceable to SI unit, and improve the test quality of aldosterone.
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Catecholamines include dopamine, norepinephrine and epinephrine. The main metabolites are 3-methoxytyramine, normetanephrine, metanephrine,homovanillic acid and vanillylmandelic acid. Detection of catecholamines and their metabolites is the cornerstone for the diagnosis of neuroendocrine tumors derived from neural crest such as pheochromocytoma, paraganglioma and neuroblastoma. Liquid chromatography tandem mass spectrometry has been widely used in the detection of catecholamines and their metabolites due to its high sensitivity and high specificity. However, the results of liquid chromatography tandem mass spectrometry in different laboratories are quite different and lack comparability. Accurate determination of catecholamines and their mtabolites in plasma and urine is currently a challenge in the field of clinical detectionbecause of their susceptibility to oxidative degradation, presence of numerous interferences and low concentration in plasma and urine samples.
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Excessive or persistent inflammatory response is an important pathophysiological feature of sepsis, and the tissue damage and organ dysfunction caused by sepsis are related to the prognosis of patients. The cholinergic anti-inflammatory pathway releases acetylcholine (ACh) through the vaginal nerve and acts on the surface of the inflammatory cell α7 nicotine acetylcholine receptor (α7nAChR) to inhibit the production of inflammatory factors, so that the inflammatory response tends to be balanced. This article reviews the composition and effects of cholinergic anti-inflammatory pathways, the mechanism of regulating sepsis and its clinical application, in order to provide a new direction for the treatment of sepsis.
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Objective To evaluate the clinical application of SWI and DTI of MRI in the diagnosis and prognosis of diffuse axonal injury (DAI).Methods A retrospective case series study was conducted on the clinical data of 16 patients with DAI admitted from January 2015 to December 2017.There were nine males and seven females,aged (56.3 ± 4.1) years.According to Glasgow Coma Scale (GCS),there were seven patients with 3-8 points,eight with 9-12 points,and one with 13 points.All patients received head CT examination on admission and then received head MRI examination within one week to record the number of lesions on T1WI,T2WI,DWI,and SWI in CT and MRI examination.On the DTI sequence,five regions including the subcortical white matter,the corpus callosum,the thalamus,the cerebellum,and the brain stem were selected for measurement of the apparent diffusion coefficient (ADC) and partial fraction of anisotropy (FA) values.The Glasgow outcome scale (GOS) was evaluated 6 months after injury.The linear correlation between ADC,FA values,GCS,and GOS on admission and after 6 months were analyzed.Results The statistical analysis of CT,T1WI,T2WI,DWI and SWI in 16 patients showed that the detection rates of DAI lesions were 25.6％ (43/168),30.4％ (51/168),44.0％ (74/168),51.8％ (87/168),and 100％,respectively (P ＜0.01).The ADC values of the subcortical white matter,the corpus callosum,the thalamus,the cerebellum,and the brain stem were 0.830 ± 0.148,0.536 ± 0.169,0.838 ± 0.596,0.708 ± 0.157,and 0.713 ± 0.135,respectively,and FA values were 0.487 ± 0.103,0.142 ± 0.040,0.293 ± 0.089,0.212 ± 0.045,and 0.366 ± 0.797,respectively.The GCS on admission was (8.9 ± 3.3)points,and GOS was (4.2 ± 1.0)points six months after injury.The correlation analysis showed that the ADC value and FA value of subcortical white matter and cerebellum were not related to GCS and GOS (P ＞ 0.05).The correlation strength of ADC values in each region with the GCS score in descending order was the thalamus,the corpus callosum,and the brain stem (P ＜ 0.05 or 0.01);for ADC with the GOS score,it was the corpus callosum,the thalamus and the brain stem (P ＜0.05 or 0.01);for FA with GCS and GOS scores,it was thalamus,corpus callosum,and brainstem (P ＜ 0.05 or 0.01).Conclusion The SWI has better sensitivity to detect DAI lesions than CT and conventional MRI sequences.DTI can accurately,objectively and visually detect the integrity of cerebral white matter fibers.Both SWI and DTI can help make early diagnosis and evaluate the prognosis of DAI patients accurately.
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Objective:To study the distribution and related factors of aggressive behavior among school aged children in Nanjing.Methods:Totally 4678 primary school students in Nanjing were sampled by cluster random sampling in this study.The General questionnaire and Achenbach's child Behavior Checklist were used to investi gate the general situation and aggressive behavior.Results:The rate of aggressive behavior of school-age children in Nanjing was 3.6 ％ (167/4678).Multivariate logistic regression analysis indicated that democratic parenting style [other parenting styles (OR =1.94,95％ CI =1.10-3.42),mixed parenting style(OR =1.96,95％ CI =1.35-2.85)],and genetic screening before birth (OR =0.71,95％ CI =0.52-0.99) were protective factors for children's aggressive behavior.The factor figures of aggressive behavior were positively correlated with that of oth er behavior problems in Pearson correlation analysis (r =0.52-0.80,Ps ＜0.01).Conclusion:About 3.6％ of the school aged children in Nanjing have aggressive behavior.It is more likely to have aggressive behaviors for children who is in other parenting styles except the democratic style and never have the genetic screening before birth.And children who with aggressive behavior may co-occur with other behavior problems.