N-glycosylation profiles of the SARS-CoV-2 spike D614G mutant and its ancestral protein characterized by advanced mass spectrometry

N-glycosylation plays an important role in the structure and function of membrane and secreted proteins. The spike protein on the surface of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, is heavily glycosylated and the major target for developing vaccines, therapeutic drugs and diagnostic tests. The first major SARS-CoV-2 variant carries a D614G substitution in the spike (S-D614G) that has been associated with altered conformation, enhanced ACE2 binding, and increased infectivity and transmission. In this report, we used mass spectrometry techniques to characterize and compare the N-glycosylation of the wild type (S-614D) or variant (S-614G) SARS-CoV-2 spike glycoproteins prepared under identical conditions. The data showed that half of the N-glycosylation sequons changed their distribution of glycans in the S-614G variant. The S-614G variant showed a decrease in the relative abundance of complex-type glycans (up to 45%) and an increase in oligomannose glycans (up to 33%) on all altered sequons. These changes led to a reduction in the overall complexity of the total N-glycosylation profile. All the glycosylation sites with altered patterns were in the spike head while the glycosylation of three sites in the stalk remained unchanged between S-614G and S-614D proteins.

SARS-CoV-2 susceptibility of cell lines and substrates commonly used in diagnosis and isolation of influenza and other viruses

Coinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other viruses is inevitable as the COVID-19 pandemic continues. This study aimed to evaluate cell lines commonly used in virus diagnosis and isolation for their susceptibility to SARS-CoV-2. While multiple kidney cell lines from monkeys were susceptible and permissive to SARS-CoV-2, many cell types derived from human, dog, mink, cat, mouse, or chicken were not. Analysis of MDCK cells, which are most commonly used for surveillance and study of influenza viruses, demonstrated that they were insusceptible to SARS-CoV-2 and that the cellular barrier to productive infection was due to low expression level of the angiotensin converting enzyme 2 (ACE2) receptor and lower receptor affinity to SARS-CoV-2 spike, which could be overcome by over-expression of canine ACE2 in trans. Moreover, SARS-CoV-2 cell tropism did not appear to be affected by a D614G mutation in the spike protein.

The key role of gut-liver axis in pyrrolizidine alkaloid-induced hepatotoxicity and enterotoxicity

Pyrrolizidine alkaloids (PAs) are the most common phytotoxins with documented human hepatotoxicity. PAs require metabolic activation by cytochromes P450 to generate toxic intermediates which bind to proteins and form protein adducts, thereby causing cytotoxicity. This study investigated the role of the gut-liver axis in PA intoxication and the underlying mechanisms. We exposed mice to retrorsine (RTS), a representative PA, and for the first time found RTS-induced intestinal epithelium damage and disruption to intestinal barrier function. Using mice with tissue-selective ablation of P450 activity, we found that hepatic P450s, but not intestinal P450s, were essential for PA bioactivation. Besides, in RTS-exposed, bile duct-cannulated rats, we found the liver-derived reactive PA metabolites were transported by bile into the intestine to exert enterotoxicity. The impact of gut-derived pathogenic factors in RTS-induced hepatotoxicity was further studied in mice with dextran sulfate sodium (DSS)-induced chronic colitis. DSS treatment increased the hepatic endotoxin level and depleted hepatic reduced glutathione, thereby suppressing the PA detoxification pathway. Compared to RTS-exposed normal mice, the colitic mice displayed more severe RTS-induced hepatic vasculature damage, fibrosis, and steatosis. Overall, our findings provide the first mode-of-action evidence of PA-induced enterotoxicity and highlight the importance of gut barrier function in PA-induced liver injury.

SARS-CoV-2 spike D614G variant confers enhanced replication and transmissibility

During the evolution of SARS-CoV-2 in humans a D614G substitution in the spike (S) protein emerged and became the predominant circulating variant (S-614G) of the COVID-19 pandemic1. However, whether the increasing prevalence of the S-614G variant represents a fitness advantage that improves replication and/or transmission in humans or is merely due to founder effects remains elusive. Here, we generated isogenic SARS-CoV-2 variants and demonstrate that the S-614G variant has (i) enhanced binding to human ACE2, (ii) increased replication in primary human bronchial and nasal airway epithelial cultures as well as in a novel human ACE2 knock-in mouse model, and (iii) markedly increased replication and transmissibility in hamster and ferret models of SARS-CoV-2 infection. Collectively, our data show that while the S-614G substitution results in subtle increases in binding and replication in vitro, it provides a real competitive advantage in vivo, particularly during the transmission bottle neck, providing an explanation for the global predominance of S-614G variant among the SARS-CoV-2 viruses currently circulating.

Establishment of a candidate reference method for serum calcium determination based on inductively coupled plasma mass spectrometry / 中华检验医学杂志

Objective@#To establish a candidate reference method for serum calcium determination based on inductively coupled plasma mass spectrometry(ICP-MS).@*Methods@#Establishment of methodology: serum samples collected from the hospital were diluted 100 times by 0.3% ultrapure nitric acid. Calcium standard solutions with different concentrations were added to serum samples matrix solutions. Serum calcium concentration was calculated according to the standard addition method using germanium (Ge) as internal standard. The linearity, precision, trueness of the performance of the established candidate reference method were evaluated, and a comparison with the reference method was made.@*Results@#The linearity was good in serum calcium concentrations from 0.000 mmol/L to 20.400 mmol/L (the concentration after dilution from 0.000 mmol/L to 0.204 mmol/L) (R2>0.999 9);the within-run precision was from 0.22% to 0.47%, and the between-run precision was from 0.64% to 0.77%; the total precision was from 0.98% to 1.09%. The determination results of 3 concentrations of SRM 956d were all in the uncertainty range required bythe certificate. The biases were -0.16%, 0.04% and 0.23%, respectively. The established candidate reference method participated in and passed the 2017 External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine (RELA) comparison. The results of the established candidate reference method were consistent well with those of the reference method in the Joint Committee for Traceability in Laboratory Medicine (JCTLM) list. There was a good correlation between the established candidate reference method and the clinical routine electrode method.@*Conclusions@#The established candidate reference method for serum calcium determination based on ICP-MS is precise, accurate, with wide range of linearity.It is expected to play a role in tracing the quantities of serum calcium in clinical laboratories.

Hepatic and intestinal biotransformation gene expression and drug disposition in a dextran sulfate sodium-induced colitis mouse model

We examined the impact of gut inflammation on the expression of cytochrome P450 (P450) and other biotransformation genes in male mice using a dextran sulfate sodium (DSS)-induced colitis model. Several P450 isoforms, including CYP1A, CYP2B, CYP2C, and CYP3A, were down-regulated, accompanied by decreases in microsomal metabolism of diclofenac and nifedipine, in the liver and small intestine. The impact of the colitis on clearance of oral drugs varied for four different drugs tested: a small decrease for nifedipine, a relatively large decrease for lovastatin, but no change for pravastatin, and a large decrease in the absorption of cyclosporine A. To further assess the scope of influence of gut inflammation on gene expression, we performed genome-wide expression analysis using RNA-seq, which showed down-regulation of many CYPs, non-CYP phase-I enzymes, phase-II enzymes and transporters, and up-regulation of many other members of these gene families, in both liver and intestine of adult C57BL/6 mice, by DSS-induced colitis. Overall, our results indicate that gut inflammation suppresses the expression of many P450s and other biotransformation genes in the intestine and liver, and alters the pharmacokinetics for some but not all drugs, potentially affecting therapeutic efficacy or causing adverse effects in a drug-specific fashion.

A study of preschoolers tooth-brushing behavior in Shaanxi province / 中国实用护理杂志

Objective:Understand the status of brushing teeth behavior of preschoolers in Shaanxi Province, to provide basis for oral health of preschoolers.Methods:By adopting the methods of multi-stage, stratified, geometric and cluster sampling, 1 370 kindergarten students at the age of 3-5 in Shaanxi Province were sampled as respondents to implement oral health questionnaire.Results:49.2%(674/1 370) children brushed their teeth every day, including only 14.8%(203/1 370) children brushing their teeth twice or above. Therefore, the difference of the brushing frequency (≥ 1 time/day) between urban and rural areas had obvious statistical significance ( χ2 value was 47.588, P<0.01). 98.7%(741/750) children used toothpaste, including only 6.9% (51/741) using toothpaste with fluoride. Therefore, the use of toothpaste between urban and rural areas has no statistical significance. Only 0.5% (4/751) children started to brush their teeth when their first deciduous tooth erupted. Therefore, the age for children starting to brush their teeth between urban and rural areas had obvious statistical significance ( χ2 value was 24.217, P<0.01). 65.2% (490/751)parents never helped their children to brush teeth, parents in rural areas even reached to 72.8% (227/312). Therefore, the brushing frequency for parents helping their children to brush teeth between urban and rural areas had statistical difference ( χ2 value was 16.192, P<0.01). Conclusions:The status of brushing teeth behavior of preschoolers in Shaanxi Province is lower than the national level, and the level in rural areas is obviously lower that in urban areas. The education and cultivation on brushing teeth behavior should be further strengthened in the future propaganda and education, especially, the power of propaganda on children and parents in rural areas should be strengthened.

Establishment of a candidate reference method for serum calcium determination based on inductively coupled plasma mass spectrometry / 中华检验医学杂志

Objective:To establish a candidate reference method for serum calcium determination based on inductively coupled plasma mass spectrometry(ICP-MS).Methods:Establishment of methodology: serum samples collected from the hospital were diluted 100 times by 0.3% ultrapure nitric acid. Calcium standard solutions with different concentrations were added to serum samples matrix solutions. Serum calcium concentration was calculated according to the standard addition method using germanium (Ge) as internal standard. The linearity, precision, trueness of the performance of the established candidate reference method were evaluated, and a comparison with the reference method was made.Results:The linearity was good in serum calcium concentrations from 0.000 mmol/L to 20.400 mmol/L (the concentration after dilution from 0.000 mmol/L to 0.204 mmol/L) (R 2>0.999 9);the within-run precision was from 0.22% to 0.47%, and the between-run precision was from 0.64% to 0.77%; the total precision was from 0.98% to 1.09%. The determination results of 3 concentrations of SRM 956d were all in the uncertainty range required bythe certificate. The biases were -0.16%, 0.04% and 0.23%, respectively. The established candidate reference method participated in and passed the 2017 External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine (RELA) comparison. The results of the established candidate reference method were consistent well with those of the reference method in the Joint Committee for Traceability in Laboratory Medicine (JCTLM) list. There was a good correlation between the established candidate reference method and the clinical routine electrode method. Conclusions:The established candidate reference method for serum calcium determination based on ICP-MS is precise, accurate, with wide range of linearity.It is expected to play a role in tracing the quantities of serum calcium in clinical laboratories.

Quantification of serum apolipoprotein E and patient phenotyping using isotope dilution liquid chromatography-tandem mass spectrometry / 中华检验医学杂志

Objective To establish an isotope dilution liquid chromatography tandem mass spectrometry method (ID-LC-MS) for quantification of serum apolipoprotein E and phenotyping. Methods Method establishment. Samples underwent denaturing, alkylation and trypsin digestion with addition of internal standards as isotope labelling arginine. SB-C18 column was used for the liquid chromatographic separation and mass spectrometry positive ion mode and multiple reaction monitoring were employed for quantification and phenotyping. Precision, accuracy and linearity were investigated for method evaluation. 40 serum samples from Shanghai Dongfang Hospital during Oct. to Dec., 2018 were used for method comparison between ID-LC-MS and immunoassay. Deming regression and Bland-Altman were used for method comparison analysis and SPSS 24 for linearity. Results Target peptides reached their releasing maximum within 4 hours and SE did at 3 hours. 3 phenotyping of ApoE were observed, such as E3/E3, E2/E3 and E3 / E4. The imprecision of IQC was 5.2 ％ . The relative bias for low and high levels of accuracy-based samples was 7.6 ％ and 3.6 ％, respectively. Deming regression showed the intercept with 95 ％ confidence interval (CI) was 6.44-11.44 (P<0.05 and the 95％ confidence interval for the slopewas 0.77-0.89 (P<0.05). The coefficient was r=0.97. The mean difference was - 2.95 mg / L with 95 ％ CI-4.26--1.65 mg/L. The linearity covered from 16.9 to 58.5 mg/L. Conclusion ID-LC-MS can be used to quantify serum apolipoprotein E and simultaneously detect its phenotyping.

Exploration on impacting factors for restricting two-way referral system from patient's perspective / 重庆医学

Objective To explore and discuss the factors for restricting the two-way referral system from the patient's perspective in order to promote the formation of hierarchical medical system in Changsha City.Methods The stratified random sampling method was adopted to divide the Chansha City into the 3 grades of high,middle and low according to the regional economical development situation,2 districts in one grade,including 6 districts.Then each district was redivided into high,middle and low grades according to the economic situation,2 basic medical institutions were selected from each grade.A total of 360 patients were randomly sampled for conducting the questionnaire investigation.The patients and doctors specially participating in the two-way referral conducted the deep interview.Results The patients choosing to primary hospital for first visit accounted for 60.9％.The awareness degree of patients to two-way referral system was 21.1％,and the two-way referral service satisfaction in the patients with two-way referral was 85.7 ％.The patients' will of transfer treatment from primary hospital to superior hospital in case of disease condition need was 82.9 ％.The patients' will for conducting rehabilitation treatment from superior hospital to primary hospital was 77.6 ％.Conclusion Few patients choose primary hospital for first visit.The signing rate of family contract services is low and awareness degree of two-way referral system is not high.

Compressed sensing magnetic resonance image reconstruction based on double sparse model / 生物医学工程学杂志

The medical magnetic resonance (MR) image reconstruction is one of the key technologies in the field of magnetic resonance imaging (MRI). The compressed sensing (CS) theory indicates that the image can be reconstructed accurately from highly undersampled measurements by using the sparsity of the MR image. However, how to improve the image reconstruction quality by employing more sparse priors of the image becomes a crucial issue for MRI. In this paper, an adaptive image reconstruction model fusing the double dictionary learning is proposed by exploiting sparse priors of the MR image in the image domain and transform domain. The double sparse model which combines synthesis sparse model with sparse transform model is applied to the CS MR image reconstruction according to the complementarity of synthesis sparse and sparse transform model. Making full use of the two sparse priors of the image under the synthesis dictionary and transform dictionary learning, the proposed model is tackled in stages by the iterative alternating minimization algorithm. The solution procedure needs to utilize the synthesis and transform K-singular value decomposition (K-SVD) algorithms. Compared with the existing MRI models, the experimental results show that the proposed model can more efficiently improve the quality of the image reconstruction, and has faster convergence speed and better robustness to noise.

Effect of Cognitive Behavioral Multi-level Intervention on Post-stroke Depression / 中国康复理论与实践

@#Objective To investigate the effect of cognitive behavioral multi-level intervention on post-stroke depression. Methods 160 patients with post-stroke depression in our hospital from February 2013 to February 2015 were divided into control group (n=80) and obser-vation group (n=80). Both groups received conventional medical treatment and nursing care. The observation group received cognitive be-havioral multi-level intervention nursing care, including personal psychology, behaviour and joint relationship. Self-rating Depression Scale (SDS) was assessed, and the serum level of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α(TNF-α) were mesured before and after treatment. Results After treatment, the score of SDS was lower (t=2.705, P<0.05), and the levels of IL-1β(t=8.182), IL-6 (t=2.883), TNF-α(t=2.604) were lower in the observation group than in the control group (P<0.05). The incidence of depression was also lower in the observa-tion group than in the control group ( χ 2=6.144, P<0.05) after 6 months follow-up. Conclusion Cognitive behavioral multi-level interven-tion could effectively prevent post-stroke depression.

Problems and countermeasures research of the management of medical teaching archives in affiliated hospital / 中国医学装备

Objective: To improve the convenience of using the medical teaching archives and the efficiency of resource sharing as well as to enhance the level of administrative ability through the analysis of the management problems of medical teaching archives in affiliated hospital. Methods: Reinforcing the awareness of medical teaching archives and Perfecting the administrative system and principles so as to develop an united format and formalize the ways of taking care of those archives, accelerating the pace of information age and enhancing Professional quality of management personnel. Results: The rate of complete medical teaching archives is close to 100 percent. The convenience to reach is increased. Conclusion:A qualitative leap is observed in the administration of medical teaching archives. The medical teaching quality has been greatly improved.

Improving the measurement precision of the phantom model by network decomposition method / 医疗卫生装备

It is a kind of precise method tomeasure the complex permittivities of the phantom model by vector network analyzer.But it is difficult tomeasure them accurately because the phantom model is jelly-like gel and is hard tobe shaped.Network decompositon method can be used toresolve it and it has great meaning tostudy the phantom model simulating the biologic tissue.

Measuring the complex permittivity of phantom model by perturbation method / 医疗卫生装备

It is the measurement of high-loss dielectric to measure the permittivity and conductivity of biologic tissue.But now it is difficult to measure them accurately.Good result is got by measuring complex permittivity of phantom model at2450MHz using perturbation method,which is meaningful for the research on biologic tissue simulation by phantom model.

Research of high precision of temperature measurement in microwave hyperthermia therapy / 中国医疗器械杂志

This paper describes a new method of temperature measurement in microwave field. This method resolves a series of problems such as the microwave field suppression, the linearization of the temperature sensor and the sensor exchangeability.

The Study and Value of Radiologic Anatomy of Mammary Duct / 实用放射学杂志

Objective:To improve the radiologic diagnostic and treatable rate of mannmmary ductal diseases.Methods:We retrospectively analyzed the galactographic materials of 369 cases.Results:The mammary ducts were classified into 4 types according to their morpholgy,including general fruticoses,multiple fruticoses,less fruticoses and single fruticoses.In this group,the multiple and less fruticoses were the most common,the general and single fruticoses were the less.Conclusion:Understanding radiologic anatomy of mammary duct is very valuable in the diagnosis and treatment of mammary ductal diseases. [