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Carotid is in a high risk of atherosclerosis due to its special geometric features and complex flow characteristics. Various biomechanical parameters are practical tools for carotid risk assessment. It has beenwidely accepted that oscillatory low shear environment promotes plaque formation. Based on this, more and more biomechanical indexes have been proposed, such as time-average wall shear stress, oscillatory shear index, relative residence time and so on. In this paper, multiple biomechanical parameters were introduced from the perspectives of shear stress and its temporal and spatial variation, turbulence, platelet transport and activation, stress concentration in vascular wall, etc. The development trend of biomechanical parameters related to carotid artery risk assessment was also analyzed, so as to provide the theoretical basis for more comprehensive and rapid carotid risk assessment
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OBJECTIVE@#To construct a modABC gene knockout strain of Proteus mirabilis and explore the effect of modABC gene deletion on biological characteristics of Proteus mirabilis.@*METHODS@#Fusion PCR was used to obtain the fusion gene of modABC and the kanamycin-resistant gene Kn, which was ligated with the suicide vector pCVD442 and transduced into Proteus mirabilis. The modABC gene knockout strain of Proteus mirabilis was obtained after homologous recombination with the suicide vector. PCR and Sanger sequencing were used to identify genomic deletion of modABC gene in the genetically modified strain. The concentration of molybdate in the wild-type and gene knockout strains was determined using inductively coupled plasma mass spectrometry (ICP-MS), and their survival ability in LB medium was compared under both aerobic and anaerobic conditions.@*RESULTS@#PCR and sanger sequencing confirmed genomic deletion of modABC gene in the obtained Proteus mirabilis strain. The concentration of intracellular molybdenum in the modABC gene knockout strain was 1.22 mg/kg, significantly lower than that in the wild-type strain (1.46 mg/kg, P < 0.001). Under the aerobic condition, the modABC gene knockout strain grown in LB medium showed no significant changes in survival ability compared with the wild-type strain, but its proliferation rate decreased significantly under the anaerobic condition and also when cultured in nitrate-containing LB medium under anaerobic condition.@*CONCLUSION@#Homologous recombination with the suicide vector can be used for modABC gene knockout in Proteus mirabilis. modABC gene participates in molybdate uptake and is associated with anaerobic growth of Proteus mirabilis in the presence of nitrate.
Subject(s)
Humans , Gene Deletion , Nitrates , Proteus mirabilis/genetics , Gene Knockout TechniquesABSTRACT
Cardiovascular disease is the leading cause of death worldwide, accounting for 48.0% of all deaths in Europe and 34.3% in the United States. Studies have shown that arterial stiffness takes precedence over vascular structural changes and is therefore considered to be an independent predictor of many cardiovascular diseases. At the same time, the characteristics of Korotkoff signal is related to vascular compliance. The purpose of this study is to explore the feasibility of detecting vascular stiffness based on the characteristics of Korotkoff signal. First, the Korotkoff signals of normal and stiff vessels were collected and preprocessed. Then the scattering features of Korotkoff signal were extracted by wavelet scattering network. Next, the long short-term memory (LSTM) network was established as a classification model to classify the normal and stiff vessels according to the scattering features. Finally, the performance of the classification model was evaluated by some parameters, such as accuracy, sensitivity, and specificity. In this study, 97 cases of Korotkoff signal were collected, including 47 cases from normal vessels and 50 cases from stiff vessels, which were divided into training set and test set according to the ratio of 8 : 2. The accuracy, sensitivity and specificity of the final classification model was 86.4%, 92.3% and 77.8%, respectively. At present, non-invasive screening method for vascular stiffness is very limited. The results of this study show that the characteristics of Korotkoff signal are affected by vascular compliance, and it is feasible to use the characteristics of Korotkoff signal to detect vascular stiffness. This study might be providing a new idea for non-invasive detection of vascular stiffness.
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Humans , Vascular Stiffness , Neural Networks, Computer , Cardiovascular Diseases/diagnosis , Sensitivity and SpecificityABSTRACT
Objective:To investigate whether memantine hydrochloride (MEM) could promote the bactericidal effect of neutrophils against methicillin-resistant Staphylococcus aureus (MRSA) and the possible mechanism. Methods:Neutrophils were co-incubated with different concentrations of MEM and MRSA for 4 h. Then the cell lysates were collected and cultured on plate for survival bacteria counting. After co-incubation, the neutrophils were collected to detect the production of reactive oxygen species (ROS) and the release of neutrophil extracellular traps (NETs). A mouse model of MRSA infection was established, and then the mice were treated with or without MEM. Blood, spleen and kidney samples were collected from the mice for bacterial colony counting and blood procalcitonin (PCT) detection. In the 48 h survival experiment, the mice were first infected with MRSA, and then treated with MEM or PBS. The survival rates of the mice were calculated and the survival curves were drawn.Results:The number of MRSA co-cultured with neutrophils decreased significantly in the presence of MEM, and within a certain concentration range, the survival number of MRSA decreased with the increase of MEM concentration. Moreover, MEM could significantly promote the production of ROS by neutrophils and the formation of NETs. In vivo experiment showed that the concentration of PCT in mouse blood samples was lower in the MRSA+ MEM group than in the MRSA+ PBS group. The animal experiment also revealed that MEM significantly decreased the bacteria loads in mouse blood and organs and increased the 48 h survival rate after MRSA infection.Conclusions:MEM could significantly promote the bactericidal effect of neutrophils against MRSA, which might be related to the enhanced generation of ROS by neutrophils and the formation of NETs.
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OBJECTIVE To co mpare the difference of liposoluble constitue nts in different processed products of Huaizhong No.1 Rehmannia glutionsa （fresh R. glutionsa ，R. glutionsa and prepared R. glutionsa ），and to evaluate its in vitro antioxidant activity preliminarily. METHODS Liposoluble extracts were extracted from 3 processed products of R. glutionsa by Soxhlet extraction. Their constituents were analyzed by gas chromatography-mass spectrometry. The spectral library of NIST 98 system was used to automatically retrieve the mass spectrum information of components ，and the structures of compounds were identified in combination with relevant literature and by comparing with eight peak index and EPA/NIH library. Relative contents of the components were calculated by using peak area normalization method with Hewlett Packard software. The antioxidant activities of liposoluble constituents in 3 processed products of R. glutionsa were investigated by 1，1-diphenyl-2-picrylhydrazyl（DPPH）free radical scavenging. RESULTS A total of 79 liposoluble components were identified from different processed products of R. glutionsa，and 48，52 and 37 liposoluble compounds were identified from fresh R. glutionsa ，R. glutionsa and prepared R. glutionsa，respectively；their relative contents accounted for 92.69％，86.29％，92.89％ of the total components respectively. Among them ，there were 20 liposoluble compounds totally ，and their relative contents accounted for 88.73％，80.89％ and 85.87％ of liposoluble components in each processed product respectively ；they were mainly composed of fatty acids such as methyl linoleate，methyl palmitate and methyl oleate. In addition ，there were 18 unique liposoluble components in fresh R. glutionsa ， mostly terpenoids ；there were 17 and 6 unique liposoluble components in R. glutionsa and prepared R. glutionsa ，mostly alkanes. The results of antioxidant experiment showed that median scavenging concentrations of liposoluble components to DPPH limeng free radical were 0.756，0.660，0.758 mg/mL，respectively. CONCLUSIONS The common liposoluble components in different processed products of R. glutionsa are mostly acids；the unique liposoluble components in fresh R. glutionsa are mostly terpenoids ，and those of R. glutionsa and prepared R. glutionsa are mostly alkanes ；the liposoluble constituents possess in vitro antioxidant activities.
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Neovascularization plays an important role in many physiological and pathological processes, but its mechanism is still unclear. Since vascular cells are subjected to a variety of biochemical and biomechanical stimulations in vivo and live in a complex microenvironment, it is necessary to construct the vascular model in vitro and simulate the in vivo microenvironment to explore the mechanism of neovascularization. Recently, owing to the advance of micromachining and microfluidic technology, various in vitro microvascular models have emerged. Variables such as shear stress, interstitial flow and biochemical gradient of angiogenic factors have been controlled in these models, which greatly promotes the research of neovascularization. The construction, development and biomechanical design of various microvascular models are reviewed in this paper.
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The most serious problem facing the implantation of vascular graft in the body is the formation of blood clots. In order to solve this problem, various attempts have been made by the scientific community for many years. However, endothelialization is the fundamental method to solve thrombosis and keep vascular graft open for a long time. Poly （ε-caprolactone） (PCL) has the advantages of biodegradability, low cost and good mechanical properties. In recent years, it has been widely used as tissue engineering scaffolds, drug deliverys and so on. This article mainly reviews the endothelialization of small-caliber vascular graft based on PCL after implanted in different animal models, as well as the endothelialization of the same animal model but under different implantation conditions, and trying to find the reasons why small-caliber vascular grafts are still not ideal in clinical applications at different angles such as the different animal models and the different way about endothelialization, and provide references for future animal model selection.
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Objective To investigate the high-fat diet effect on morphology and stiffness of endothelial cells. Methods SD rats were randomly divided into high-fat diet group (AS group, n=3) and control group (CON group, n=3). Rat aortic endothelial cells were obtained from rat thoracic aorta by explant method. Cell morphology was observed under inverted microscopy. The mean fluorescent intensity of F-actin in two groups was calculated by immunofluorescence staining. Cell stiffness was measured by atomic force microscopy (AFM). Results The endothelial cells migrated from tissue plant on the 7th day and formed confluence after cultivation for 14 days. Endothelial cells were identified by factor Ⅷ immunofluorescence staining. Cells in AS group showed enhanced perimeter (P＜0.01), aspect ratio (P＜0.01), and area (P＞0.05), while less circularity (P＜0.01) compared with the cells in control group. The mean fluorescence intensity of F-actin in AS group was significantly higher than that in control group (P＜0.01). AFM showed that the cell stiffness of AS group was significantly higher than that of control group (P＜0.01). Conclusions High-fat diet would change the morphology and stiffness of endothelial cells, which might subsequently affect their normal function and become an important incentive to AS.
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OBJECTIVE@#To explore the protective effect of SBi4211 (heptamidine), an inhibitor of S100B, against central nervous system injury induced by HIV-1 envelope protein gp120.@*METHODS@#In an @*RESULTS@#In the cell co-culture system, SBi4211 treatment significantly inhibited gp120-induced expression of S100B, RAGE and GFAP in U251 cells (@*CONCLUSIONS@#SBi4211 can protect neurons from gp120-induced neurotoxicity possibly by inhibiting the S100B/ RAGE-mediated signaling pathway.
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Animals , Mice , Astrocytes , Blotting, Western , Central Nervous System , HIV Envelope Protein gp120 , Neurons , S100 Calcium Binding Protein beta Subunit , Signal TransductionABSTRACT
Vena cava filter was widely used in clinic to prevent pulmonary embolism in treating lower extremity deep venous thrombosis（DVT）. In this paper, application status of vena cava filter was reviewed, including the way of vena cava filter implantation, filter classification, indications of filter implantation and existing problems (contraindications and complications). The frontier issues concerning study on novel filters, such as the degradation filter and drug coated filter was also analyzed, and the hemodynamic research progress from domestic scholars in recent years about filter structure was briefly summarized. The research findings provide references for further optimization of filter structure and clinical application of vena cava filter.
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Due to the three-dimensional spiral-shaped geometry of aorta, the flow pattern within the human aorta is helical in late systole. Helical flow widely exists in the human arterial system as one typical flow pattern. Studies demonstrate that the helical flow plays a positive physiological role in facilitating blood flow transport, suppressing disturbed blood flow, preventing the accumulation of atherogenic low density lipoproteins on the luminal surfaces of arteries, enhancing oxygen transport from the blood to the arterial wall and reducing the adhesion of blood cells on the arterial surface. Therefore, the potential clinical applications of helical flow were summarized, so as to provide references for the optimal design of cardiovascular interventional therapies and devices.
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Microfluidic technology refers to the technique of precise fluid control by manipulating submillimeter-scale fluids. In recent years, the use of microfluidic technology has realized the construction of organ-on-chips. The organ-on-chip refers to a micro-model with physiological functions, and cultivating living cells in a continuously perfused micro-chamber to simulate the physiological functions of tissues and organs. As the physiological function of the organ-on-chip has many advantages such as definite function, controllable microenvironment, rich measurement information, low chemical consumption, low cost, promising automation and high throughput, it has a huge application prospect in the field of drug development to solve the bottleneck problems in cellular and animal experiments, which has caused a great concern in the academic community. Although the organ-on-chip is still a very young research field, some microfluidic organ-on-chips have been developed and their potential applications are explored, including drug target optimization, drug screening and toxicity tests, and biomarker identification. In this review, the progress made in microfluidic organ microchips and their potential significance in clinical research were analyzed.
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The phenomenon of sex differences exists in patients who have abdominal aortic aneurysms (AAA). The occurrence rate of AAA is higher in male, while the rates of rupture and postoperative mortality are higher for female. This phenomenon of sex differences would affect the diagnosis, treatment and postoperative rehabilitation for AAA patients. This article reviewed the recent research status of sex differences on AAA, and explored the phenomenon of sex differences from the aspects of threshold determination, biomechanics and mechanobiology. This review points out that the sex differences on AAA could ascribe to the differences of biomechanical environment and biological properties induced by the vascular size, anatomy structure and structure components of abdominal aortic artery. The comprehensive investigations of the sex differences on AAA could help to optimize the diagnosis, treatment and device design, patient care and rehabilitation strategy of AAA based on sex differences phenomenon.
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Vascular endothelial cell glycocalyx is a layer of glycoprotein complex located on the surface of endothelial cells, forming a selective permeation barrier on the surface of endothelial cells. In the present review, after a brief introduction of glycocalyx, the relationship between glycocalyx and mass transport under fluid sheer stress (FSS), especially the relationship between glycocalyx and macromolecules such as low density lipoprotein (LDL) has been discussed. This relationship was reflected as following: on the one hand, the thickness and integrity of the glycocalyx affects the concentration polarization of LDL and its transendothelial transport and heparan sulfate proteoglycan (HSPG) participates in the whole process of residual lipoproteins metabolism. On the other hand, ox-LDL, an oxidized product of LDL, destroys heparan sulfate (HS) which is a major component of the endothelial cell glycocalyx. The study on relationship between vascular endothelial glycocalyx and lipoproteins will provide a new clue to elucidate the pathogenesis of atherosclerosis and provide more evidence to view the glycocalyx as a new control target.
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Objective To investigate the influence of straightening phenomenon caused by stent implantation on biomechanical environment changes in vascular lesions, so as to explore biomechanical mechanism of restenosis and stent optimization. Methods Based on the computed tomography (CT) images of a patient, the balloon model, the left anterior descending coronary(LAD) artery model and two stent models (idealized stent and straightened stent) were reconstructed by Mimics, Geomagic and Pro/E software. The balloon-stent-LAD artery mechanical models were then established with the ABAQUS software. Based on the numerical simulation results, the influence of straightening phenomenon on mechanical environment at vascular lesions was analyzed. Results When the stents were expanded under the same inflation pressures (1.013 MPa), the Von Mises stress increased on vascular wall of the straightened stent model compared with the idealized stent model, and stress concentration occurred especially at the proximal and distal area of the stented regions and on the myocardial surface. The average and the maximum Von Mises stress on vascular wall of the idealized stent model were 0.39 MPa and 5.12 MPa, respectively. The average and the maximum Von Mises stress on vascular wall of the straightened stent model were 0.45 MPa and 7.43 MPa, respectively. Conclusions The straightening phenomenon caused by stent implantation would change the distribution of Von Mises stress and induce stress concentration. This kind of mechanical environment would cause greater damage to vascular wall, then might cause mechanical injury and vascular remodeling, leading to a higher risk of neointimal hyperplasia and subsequent restenosis. The research findings will be helpful for explaining the mechanism of in-stent restenosis, and may provide clinical guidance for the interventional surgery and optimization of stent design.
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Objective To evaluate the diagnostic value of hepatitis C virus core antigen(HCV-cAg),hepatitis C virus(HCV-IgG) and hepatitis C virus(HCV-RNA) in the laboratory diagnosis of Hepatitis C.Methods HCV-cAg and HCV-IgG were detected by enzyme-linked immunosorbent assay(ELISA),HCV-RNA was detected by real-time fluorescent quantitative polymerase chain reaction(RT-PCR) in 84 suspected HCV patients and 87 healthy control subjects.Results In 84 suspected HCV patients,the HCV-IgG positive rate was 84.5%,HCV-cAg positive rate was 13.1%,HCV-RNA positive rate was 52.4%.Among 71 cases of HCV-IgG positive patients,there were 35 cases with negative HCV-RNA,the false positive rate was 49.3%.In 11 cases of HCV-cAg positive patients,there were 5 cases with negative HCV-RNA,the false positive rate was 45.5%.In 44 cases of HCV-RNA positive diagnosis of hepatitis C patients,HCV-IgG false negative rate was 18.2%,HCV-cAg false negative rate was 86.4%.The false negative rate of combined detection of HCV-cAg and HCV-IgG was 13.6%,and the true positive rate was 100.0%.Conclusion HCV-cAg and HCV-IgG have certain false negative and false positive in laboratory diagnosis of HCV,combine these two methods,or joint with HCV-RNA detection,could reduce the rate of missed diagnosis.
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Objective To explore the contents and modes of community nursing training and improve community care quality.Methods The training course and assessment standard were worked out according to practical work in community health service centers,including basic nursing skills,community first aid skills,hospital infection control skills,preventive health care skills and community document management skills.Toally 58 nurses from 11 community health service centers were trained for 36 hours from January to June,2016 and tested before and after training to assess the effect of training.Result After training,the scores on all skills were significantly higher than those before training (all P＜0.01).Conclusion Regular and practical training and management are the guarantee for the improvement of the community care quality.
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Objective To explore the relationship between semen leukocyte and liquefaction and sperm motility through the anal‐ysis of routine semen examination results .Methods Retrospectively analyze on 8 666 cases of routine semen examination .Accord‐ing to the leukocyte count the semen samples which had sperms were divided into three groups ,Group A :white blood cells≤1 × 106/mL ,Group B:(1-4)× 106/mL ,Group C :>4 × 106/mL .Then compare the liquefaction time and sperm motility of these three groups .Results Among the 8 666 cases of semen analysis ,there were 164 cases of azoospermia(accounting for 1 .9% ) and 8 502 fine cases(accounting for 98 .1% ) .There were 7 419 ,1 014 and 69 cases in Group A ,B ,C respectively .In the three groups ,there were 5 323 ,740 and 50 cases of normal sperm motility respectively ;there were 2 096 ,274 and 19 cases of the abnormal motility ca‐ses respectively .In the three groups ,the normal cases of semen liquefaction time were 4 593 ,608 and 43 respectively ;the abnormal were 2 826 ,406 and 26 cases respectively .Statistical analysis showed no significant correlation between semen leukocyte and lique‐faction(P=0 .712) ,and between semen leukocyte and sperm motility(P=0 .486) .There were 1 217 cases of normal sperm motility and 4 027 cases of abnormal sperm motility in normal liquefaction group;there were 1 172 cases of normal sperm motility and 2 086 cases of sperm motility in abnormal liquefied group .There was statistically significant difference between the two groups(P=0 .000<0 .05) .Conclusion There were no correlation between semen leukocyte count and liquefaction or sperm motility ,but sperm mo‐tility and liquefaction are correlated .
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Objective To investigate the level of anxiety and emotional intelligence in general nurses of community health service centers in Shenzhen city, and provide theoretical basis for the intervention of anxiety in general nurses by analyzing the relationship between anxiety and emotional intelligence . Methods The self-rating anxiety scale ( SAS ) and emotions intelligence scale ( EIS ) were employed for the survey among 92 general nurses from 20 community health service centers in Shenzhen city . Results The SAS scores was 40.18 ± 7.26, significantly higher than the national norm. The rate of anxiety was 54.35%. Thirty-nine contracted anxiety at a low level, accounting for 42.39%, 10 did at a moderate level, accounting for 10.87%, and 1 did at a higher level, accounting for 1.09%. The EIS score was 3.49 ± 0.47. The highest dimension score was management of emotions for others and the lowest score was emotional perception. The dimension of management of emotions for others was positively related to social anxiety (P<0.05), and the dimension of use of emotions negatively related to social anxiety (P<0.05). Conclusions General nurses of community health service centers in Shenzhen suffer from anxiety at a high level and their emotional intelligence is at a medium level. Both factors predict the level of social anxiety in general nurses of community health service centers . Improving the emotional intelligence can be an approach to reduce the level of anxiety.
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<p><b>OBJECTIVE</b>To assess the feasibility of chromosomal microarray analysis(CMA) for studying the correlation between birth defects and chromosomal aberrations.</p><p><b>METHODS</b>A total of 2000 patients with birth defects were recruited for the CMA testing.</p><p><b>RESULTS</b>Five hundred twenty two patients (26.1%) were found to have chromosomal abnormalities. These included 24 cases with numerical abnormalities, 11 with mosaicisms, and 11 with uniparental disomies. The remaining 476 cases were of well-known microdeletion or microduplication syndromes. The advantage of CMA over conventional karyotyping was demonstrated in many cases.</p><p><b>CONCLUSION</b>As a powerful tool for patients with birth defects, CMA can produce a higher diagnostic yield compared with conventional karyotyping.</p>