Objective This study uses whole-genome methylation capture sequencing technology to screen differential sites and regions of gene methylation in mouse liver and colon under simulated weightlessness conditions to reveal the specific impact of weightlessness on gene methylation.Methods Six 8-week-old male C57BL/6J mice were randomized into the tail suspension group and the control group,with 3 in each.The 3 mice in the tail suspension group recieved tail suspension for simulated weightlessness for 42 days.After the experiment,DNA was extracted from liver and colon tissue and analyzed using genome-wide methylation capture sequencing technology.Results DNA analysis of liver tissue showed that a total of 7 517 differentially methylated sites and 997 differentially methylated regions were found,involving 4 892 genes.DNA analysis of colon tissue revealed 70 340 differentially methylated sites and 12 004 differentially methylated regions,affecting 12 877 genes.GO and KEGG path analysis revealed that these differentially methylated genes were mainly involved in protein binding,cell adhesion,cell activation,and various metabolic pathways.Conclusion This study successfully identified differential methylation sites and regions in mouse liver and colon under simulated weightlessness conditions through high-throughput sequencing technology.These findings help to further understand the impact of long-term space residence on biological gene methylation.It provides new research ideas for the prevention and early treatment of space flight-related diseases.

With the increasing maturity and progress of China's space technology,astronauts can stay longer in the space station and complete more complex space experiments and tasks.In the Microgravity(MG)environment of space,the digestive system of astronauts is inevitably affected,especially the liver and colon,and there are many physiological and pathological changes.MG can affect liver metabolic function,cell proliferation and differentiation,oxidative stress response and inflammatory factor levels.MG can disrupt the intestinal barrier of the colon,intestinal flora and microecology,intestinal immunity,and the gut-liver axis.However,the existing studies on the effects of MG on liver and colon are not completely clear,and there is a lack of reliable diagnostic indicators for the pathological changes of both.Therefore,in order to explore the damage mechanism of MG on liver and colon and ensure the digestive system health of astronauts,this paper reviews the research progress on the effects of MG on liver and colon.

Based on the teaching concept of constructivism, this study aims to promote independent inquiry-based learning and clinical thinking among students and establish the guiding ideology of "full participation, process control, in-depth discussion, and expansion of thinking". A blending learning model was adopted with offline inquiry-based group learning and in-class defense and comment, as well as online teacher-student interaction and supervision to promote learning. Case-problem-based learning (CPBL) of pathophysiology was carried out among the medical students in the class of 2017, and process management was strengthened to effectively manage the two key links of data retrieval and group discussion. The analysis of 176 teaching evaluations collected at the end of the semester show that in terms of the overall evaluation of CPBL teaching, 162 students (92.05%) had high evaluation on teaching objectives, organization, cases, and personal gains and held a very or relatively favorable attitude. There were more negative feedbacks on "appropriate time allocation"; 21 students (11.93%) held a relatively or very disapproving attitude, and 149 students (84.66%) "felt very tired". In terms of teaching effect evaluation, 150 students (85.23%) strongly or relatively agreed that CPBL teaching may help to understand professional knowledge, stimulate learning enthusiasm and initiative, improve problem solving ability, emphasize clinical practice to cultivate clinical thinking, supervise and promote learning, and enhance team cooperation and teacher-student communication. In terms of the evaluation of teachers, 167 students (94.89%) thought that teachers were rigorous, responsible, and enthusiastic in teaching, attached importance to process management, and did well in effective guidance and thinking inspiration (strongly or relatively agree). The above results suggest that the CPBL teaching reform of pathophysiology based on process management can effectively promote in-depth inquiry-based independent learning and the cultivation of clinical thinking and improve teaching effectiveness, but further improvement is needed for teaching arrangement and time allocation.

Ebola virus (EBOV) is an enveloped negative-sense RNA virus and a member of the filovirus family. Nucleoprotein (NP) expression alone leads to the formation of inclusion bodies (IBs), which are critical for viral RNA synthesis. The matrix protein, VP40, not only plays a critical role in virus assembly/budding, but also can regulate transcription and replication of the viral genome. However, the molecular mechanism by which VP40 regulates viral RNA synthesis and virion assembly/budding is unknown. Here, we show that within IBs the N-terminus of NP recruits VP40 and is required for VLP-containing NP release. Furthermore, we find four point mutations (L692A, P697A, P698A and W699A) within the C-terminal hydrophobic core of NP result in a stronger VP40-NP interaction within IBs, sequestering VP40 within IBs, reducing VP40-VLP egress, abolishing the incorporation of NC-like structures into VP40-VLP, and inhibiting viral RNA synthesis, suggesting that the interaction of N-terminus of NP with VP40 induces a conformational change in the C-terminus of NP. Consequently, the C-terminal hydrophobic core of NP is exposed and binds VP40, thereby inhibiting RNA synthesis and initiating virion assembly/budding.
Ebolavirus/physiology* ; HEK293 Cells ; HeLa Cells ; Humans ; Nucleocapsid Proteins/metabolism* ; RNA, Viral/metabolism* ; Viral Matrix Proteins/metabolism* ; Virion/metabolism* ; Virus Assembly

Objective:To explore the effect of the location and size of region of interest (ROI) on the measurement of liver fat by means of quantitative computed tomography (QCT).Methods:A total of 98 subjects who were examined with QCT for bone mineral density examination from December 25, 2019 to January 17, 2020 were recruited continuously from the Department of Health Management of Henan Provincial People′s Hospital. The liver fat content was measured by QCT workstation. The ROI was located respectively in the left lobe, the right anterior lobe and the right posterior lobe of the liver, and it was measured independently by the A measurer and B measurer. The central position of the ROI was fixed and the diameter was increased, and it was measured by the A measurer. In this study, Friedman test was used to compare the differences of measurement results in different positions or sizes of ROI, and intra-class correlation coefficients (ICC) was used to evaluate the repeatability of inter-measurers.Results:There was a significant difference for liver fat content under different positions of ROI (χ2=62.306, P<0.001), but no difference under different seizes of ROI (χ2=1.088, P=0.581). The ICC values of the inter-measurers repeatability analysis of the A measurer and B measurer in the left lobe, right anterior lobe and right posterior lobe of the liver were 0.847, 0.917 and 0.874, all more than 0.75, and the reproducibility was good. Conclusions:When QCT technique is applied to the measurement of liver fat content, the location conditions of ROI may affect results, so it is necessary to select multiple ROI in the whole liver for measurement. The inter-measurers repeatability of QCT in different parts of the liver is good.

Objective:To provide support for the clinical application of quantitative computed tomography (QCT) in the measurement of liver fat content, this study evaluated the intra-observer and inter-observer reproducibility of liver fat content measured by QCT in a population receiving physical examinations.Methods:From April to July 2019, 291 people were consecutively selected who underwent QCT examination in the health management department of Henan Provincial People′s Hospital. There were 214 males (73.5%) and 77 females (26.5%), aged 48.7±11.0. We measured liver fat content by QCT workstation. Three observers (A, B, C) measured their liver fat content independently, then observer A performed re-testing two weeks later. The mean value of the two measurements from observer A was taken as the final result. Measurement data were described by mean±SD. Intra-observer and inter-observer reproducibility were assessed using intra-class correlation coefficients ( ICC). Results:The first measurement result for observer A was 10.46±5.55 and the second measurement for observer A was 10.66±5.59, resulting in a final value of 10.56±5.51. The measurement results of observers B and C were 10.70±5.45 and 10.86±5.77, respectively. The ICC value of liver fat content values measured by the three observers was 0.960 (95% CI: 0.951-0.967, P<0.001) and the ICC value of liver fat content values for the two measurements of observer A was 0.953 (95% CI: 0.941-0.962, P<0.001). The ICC values were>0.75, so reproducibility of results was good. Conclusions:If the measurement method is consistent, the results for liver fat content measured by a conventional CT scanner and QCT workstation will have good reproducibility between and within observers, and will also have certain clinical application prospects.

Objective: To explore the application effect of noninvasive mechanical ventilation in chronic obstructive pulmonary disease(COPD) patients with respiratory failure. Methods: From April 2016 to October 2017, 150 COPD patients with respiratory failure in Ningbo Geriatric Rehabilitation Hospital were selected, and they were divided into observation group and control group by using the random number table method, with 75 cases in each group.The control group was treated with conventional comprehensive therapy, the observation group was treated with noninvasive mechanical ventilation method on the basis of the control group.The clinical effect of the two groups was compared. Results: In the observation group, the RR, HR and arterial blood PaCO₂ were significantly better than those in the control group(t=13.29, 12.48, 13.42, all P<0.05). The PaO₂, pH value in the observation group were significantly higher than those in the control group(t=5.91, 2.88, all P<0.05). The total effective rate of the observation group was 97.33%(73/75), which was higher than 73.33%(55/75) of the control group, the difference was statistically significant(χ²=1.81, P<0.05). Conclusion Application of noninvasive mechanical ventilation in COPD patients with respiratory failure can significantly improve respiratory function, and not only effectively shorten the treatment time, but also improve the treatment effect, and it is worthy of clinical promotion.

Objective To observe the effect of treadmill exercise on the expression of transforming growth factor-β1 (TGF-β1) and its receptor Smad3 protein as well as on cell apoptosis in the ischemic boundary zone,so as to explore how exercise promotes the recovery of neurological function after cerebral ischemia.Methods Thirty adult male Sprague-Dawley rats were randomly divided into a sham group (n=6),a model group (n=12) and an exercise group (n=12).A modified Longa's method was used to establish an animal model of cerebral ischemia by occluding the right middle cerebral artery in the rats of the model and exercise groups.Those of the sham group were subjected to the same surgical procedure except that no thread was inserted.After 24h the exercise group began treadmill training,while the other two groups were left on the treadmill without training.Modified neurological severity scores (mNSSs) were used to quantify the rats' neurological functioning on the 3rd,7th and 14th day after the surgery.The ischemic boundary zone tissue was then dissected to detect the expression of TGF-31 and Smad3 protein using western blotting.Cell apoptosis was detected by TUNEL staining.Results The average mNSS scores of the exercise group on the 7th and the 14th day were significantly lower than those of the model group at the same time points.The average expression level of TGF-β1 and Smad3 protein in the exercise group was significantly higher than in the model group.The number of TUNEL-positive cells in the exercise group was significantly lower than in the model group on the 14th day.Conclusions Treadmill exercise can improve the recovery of neurological function after cerebral ischemia.It may be partly due to upregulating the expression of TGF-β1 and Smad3 protein,which inhibit cell apoptosis in the ischemic boundary zone.

To develop a specific, rapid, and convenient immunochromatography assay (ICA) to detect melamine residues in dairy products and feed sample. Colloidal gold particles labeled with purified monoclonal antibody against anti-melamine were used as the detector reagent. The MEL-OVA (the conjugate of melamine and ovalbumin) and goat anti-mouse melamine IgG were blotted on the test and control regions of nitrocellulose membrane. The strip was then assembled with sample pad, absorbing pad, and dorsal shield. The limit of detection (LOD) is 50 microg/L. The test trip was applied to detect melamine in milk, milk powder, and animal feeds, with detection limits of 100 microg/L for milk, 100 ng/g for milk powder, 200 ng/g for feeds. Compared to LC-MS/MS, the ICA could be used to screen a large number of dairy products and feed samples for melamine residue.
Animals ; Antibodies, Monoclonal ; chemistry ; Cattle ; Dairy Products ; analysis ; Food Contamination ; analysis ; Gold Colloid ; chemistry ; Immunochromatography ; methods ; Milk ; chemistry ; Reagent Strips ; chemical synthesis ; chemistry ; Sensitivity and Specificity ; Triazines ; analysis

This study investigated the tight junction (TJ) protein expression of the intestinal mucosa in a rat tail-suspension model under simulated weightlessness.Twenty-four Wistar rats were randomly divided into three groups:CON group (n=8),control; SUS-14 d group (n=8),tail-suspension for 14 days;SUS-21 d group (n=8),tail-suspension for 21 days.Occludin and Zonula Occluden-1 (ZO-1) expression levels were determined by immunohistochemical analysis and mRNA fluorescent quantitative PCR.Plasma levels of diamine oxidase (DAO) and d-lactate were determined using enzymatic spectrophotometry.Immunohistochemical results for occludin and ZO-1 showed disruption of the TJs in the intestinal mucosa in SUS-14 d and SUS-21 d groups.The expression levels of occludin and ZO-1 in SUS-21 d group were lower than those in SUS-14 d group,and significantly lower than those in CON group (Occldin:0.86±0.02 vs 1.01±0.03 vs 1.63±0.03 and ZO-1:0.82±0.01 vs 1.00±0.02 vs 1.55±0.01,P＜0.01).Moreover,the levels of plasma DAO and d-lactate in SUS-21 d group were higher than those in SUS-14 d group,and significantly higher than those in CON group (DAO:27.58±0.49 vs 20.74±0.49 vs 12.94±0.21 and d-lactate:37.86±0.74 vs 28.26±1.01 vs 17.76±0.91,P＜0.01).There were significant negative co rrelations between occludin or ZO-1 expression levels and DAO (r2=0.9014,r2=0.9355,P＜0.01) or d-lactate levels (r2=0.8989,r2=0.9331,P＜0.01).Occludin and Zo-1 were reduced in intestinal mucosa both in mRNA and protein levels in the rat tail-suspension model.The significant negative correlations between expression levels of TJs and plasma levels of DAO or d-lactate support the hypothesis that intestinal permeability is increased due to a decrease in TJ protein expression during tail-suspension from 14 days to 21 days.