Dynamic Response and Injury Prediction for Lumbar Vertebrae of Pilots with Spondylolysis under Persistent Overload / 医用生物力学

Objective Based on construction and verification of the lumbar finite element model, the simulation calculation and injury prediction on dynamic response of normal lumbar model and L5 unilateral and bilateral spondylolysis models of the pilot were carried out, so as to explore the influence of persistent flight overload on normal and spondylolysis lumbar vertebrae of the pilot. Methods The precise finite element model of lumbavertebrae was established using reverse engineering software and computer-aided engineering (CAE) technology based on CT images. The validity of the lumbar vertebrae model was verified by static and dynamic in vitro experiments. The biomechanical simulation analysis on normal and spondylolysis lumbar vertebrae of the pilotunder persistent overload was carried out, and the spinal injury was predicted and analyzed by dynamic response index (DRI) injury evaluation and prediction method. Results The maximum isthmus stress of L5 vertebra in unilateral and bilateral spondylolysis models were 105. 29 MPa and 126. 32 MPa, respectively, which were significantly higher than those in normal model. The L4-5 and L5-S1 intervertebral discs of the spondylolysis model were more prone to premature degenerative changes than those of normal model. Combined with DRI spinal injury prediction method, the probability of spinal injury in normal lumbar vertebrae, lumbar vertebrae with L5 unilateral and bilateral spondylolysis were 0. 001 4% , 2. 26% and 3. 21% , respectively, and the probability of spinal injury was significantly increased after the occurrence of spondylolysis. Conclusions The spondylolysis increases the load of lumbar isthmus under flight overload. The results provide more accurate data support for the formulation of training programs and the development of protective devices to ensure flight safety

Research progress of traditional Chinese medicine in the prevention and treatment of COVID-19 / 中国热带医学

@#Abstract: The coronavirus disease 2019 (COVID-19) has become a global public health problem due to its highly contagious nature. This article aims to discuss the current situation of traditional Chinese medicine in the prevention and treatment of COVID-19, and to provide a basis for traditional Chinese medicine research and scientific and standardized treatment of COVID-19.In this article, the etiology, pathogenesis, treatment plan and research progress were summarized, analyzed and concluded by retrieving and reviewing the literature and clinical reports related to the prevention and treatment of COVID-19 with traditional Chinese medicine. Traditional Chinese medicine has obvious effects in the prevention and treatment of COVID-19, improvement of clinical symptoms, and control of disease progression, which had the unique advantages of mild curative efficacy and safety. It has important practical significance in relieving patients' early symptoms and reducing the incidence of progression from mild to severe, and had great potential for development in the treatment of COVID-19. The traditional Chinese medicine intervention and the formulation of diagnosis and treatment plans for the COVID-19 need to be continuously optimized and improved. Scientific and rational application of traditional Chinese medicine to prevent and treat COVID-19, optimization diagnosis and treatment programs, and in-depth exploration of pharmacological mechanisms, especially the provide reference for early intervention of new coronavirus pneumonia by traditional Chinese medicine, the control of disease progression in the middle stage, and improve prognosis in the late stage with Western medicine.

Regulatory role of the transcriptional coactivator Mediator 1 in skin hair regeneration and its mechanisms / 中华皮肤科杂志

Objective:To investigate the effect of the transcriptional coactivator Mediator 1 (Med1) on mouse hair regeneration, and to explore potential mechanisms.Methods:Med1 flox/flox C57BL/6J mice were mated with K14-Cre mice, and the mice with epidermis-specific knockout of Med1 gene, namely K14-Cre-expressing Med1 flox/flox mice (knockout group) , were obtained by using the Cre-Loxp system, while Med1 flox/flox mice without K14-Cre expression served as control group. Mice in the two groups (3 mice in each group) were raised together for 8 weeks followed by dorsal hair removal. Hair regeneration was observed for 12 consecutive days after hair removal. After 12 days, all mice in the two groups were sacrificed, their depilated and non-depilated dorsal skin tissues were resected, and total RNA was extracted from the tissues. Real-time quantitative PCR was performed to determine the mRNA expression of hair keratin genes, vitamin D receptor/β-catenin pathway-related genes, and genes associated with maintenance of hair follicle stem cell proliferation and quiescence. Paraffin-embedded sections of depilated and non-depilated mouse skin tissues were prepared, and immunofluorescence staining was conducted to determine the number of stem cells in the hair follicle bulge. Two-independent-sample t test was used for comparisons between two groups. Results:From days 0 to 12 after depilation, hair regeneration was delayed in the depilated skin area in the knockout group compared with the control group. Real-time quantitative PCR showed significantly decreased mRNA relative expression levels of hair keratin genes Ha1 and Krt2-16, vitamin D receptor/β-catenin pathway-related genes S100a3, Dlx3 and Tubb3, and genes associated with maintenance of hair follicle stem cell proliferation and quiescence including Lhx2, Sox9 and Nfatc1 in the depilated skin tissues in the knockout group (22.09 ± 12.32, 2.07 ± 0.20, 0.02 ± 0.01, 12.36 ± 2.12, 1.75 ± 0.46, 0.39 ± 0.02, 4.42 ± 0.76, 0.44 ± 0.07, respectively) compared with the control group (70.53 ± 9.46, 7.76 ± 0.49, 0.05 ± 0.01, 26.16 ± 2.96, 2.60 ± 0.14, 0.71 ± 0.09, 11.93 ± 0.42, 0.75 ± 0.04, respectively; t = 5.40, 18.64, 3.89, 6.57, 3.04, 6.10, 15.03, 6.18, respectively, all P < 0.05) . Immunofluorescence staining showed that the number of CD34 +K15 + hair follicle stem cells in the hair follicle bulge in both depilated and non-depilated skin tissues was significantly lower in the knockout group than in the control group. Conclusion:Med1 gene knockout may down-regulate the expression of downstream genes of the vitamin D receptor/β-catenin pathway and genes associated with maintenance of hair follicle stem cell proliferation and quiescence (Sox9, Nfatc1 and Lhx2) , and reduce the number of hair follicle stem cells, leading to hair follicle differentiation disorder and hair regeneration delay.

Dynamic Response Simulation and Damage Prediction of Pilot Cervical Vertebra During Maneuver Flight / 医用生物力学

Objective To simulate dynamic response of cervical spine of the pilot during typical maneuver flight movements using finite element method, as well as make analysis and prediction on damage failure of the pilot neck during flight by impact injury and fatigue injury model of biological tissues.Methods A geometrically accurate finite element model of the neck was constructed, and validity of the model was verified by relevant examples. Then, the acceleration curves of centrifugal trainer under different modes were loaded for numerical simulation, and impact injury and fatigue injury of tissues were predicted by using the universal cervical injury criterion and the fatigue damage model of biological tissues.Results The maximum stress of the vertebrae and intervertebral disc caused by overload impact was 66.53 MPa and 58.63 MPa respectively during typical maneuver flight. According to the Nij injury criteria, the maximum Nij was 0.096, which was lower than the injury tolerance threshold of 1, and would not cause direct acute injury to cervical tissues. Based on fatigue damage model of biological tissues, it was found that cancellous bone suffered fatigue failure under the condition of uninterrupted repeated loading for more than 40 000 times. Considering the limited flight career of the pilot, the vertebral tissues would not be fractured due to the accumulation of fatigue damage.Conclusions To a certain extent, the results can contribute to formulating pilot training and flight plans, and also provide data support for the development of its protective equipment.

Mediating effect of sleep quality on mobile phone dependence and loneliness in university students / 预防医学

Objective @#To explore the mediating effect of sleep quality on mobile phone dependence and loneliness in university students, so as to provide evidence for prevention and intervention of mobile phone dependence.@*Methods @#A survey was conducted from December 2019 and January 2020 among the students of Guangzhou Medical University. The general information questionnaire, mobile phone dependence index scale, UCLA loneliness scale and Pittsburgh sleep quality index scale were used to analyze the mediating effects of sleep quality on mobile phone dependence and loneliness. @*Results @#A total of 575 questionnaires were distributed and 573 valid ones were collected, with an efficiency of 99.65%. The detection rate of 115 students with mobile phone dependence was 20.07%, and that of 203 students with sleep quality problems was 35.43%. The students scored ( 48.03±6.07 ) points in loneliness, and 405 of them had high level. Mobile phone dependence was positively correlated with loneliness and sleep quality ( r=0.299, 0.385, both P<0.05 ); loneliness was positively correlated with sleep quality ( r=0.553, P<0.05 ). Mobile phone dependence and sleep quality both could positively predict loneliness, mobile phone dependence could positively predict sleep quality, and sleep quality and gender had a significant interaction effect on loneliness ( all P<0.05 ). The mediating effect value of sleep quality on mobile phone dependence and loneliness was 0.290 ( 95%CI: 0.186-0.400 ) in males and 0.131 ( 95%CI: 0.084-0.187 ) in females.@*Conclusion@#Sleep quality has a mediating effect on mobile phone dependence and loneliness among university students. Male students are susceptible to the negative effects of mobile phone dependence.

Effect of topical nitric oxide donors on epidermal hyperplasia in mice with impaired barrier function / 中华皮肤科杂志

Objective:To evaluate the effect of nitric oxide on epidermal hyperplasia in mice with impaired barrier function.Methods:Fifteen SKH1 hairless mice were divided into 4 groups by using a random number table: normal control group (3 mice) , S-nitroso-N-acetyl-DL-penicillamine (SNAP) group (4 mice) , barrier-impaired group (4 mice) , SNAP-treated barrier-impaired group (4 mice) . Fifteen C57BL/6J mice were randomly and equally divided into 3 groups: normal control group, barrier-impaired group and sodium nitroprusside (SNP) -treated barrier-impaired group. Mice in the two normal control groups were both topically treated with propylene glycol-ethanol mixtures on the back; those in the SNAP group were topically treated with SNAP solution alone; those in the two barrier-impaired groups were both treated with repeated tape peeling followed by topical application of propylene glycol-ethanol mixtures on the back twice a day; those in the SNAP-or SNP-treated barrier-impaired group were treated with repeated tape peeling followed by topical application of 10-mmol/L SNAP or SNP solution on the back twice a day. After 4 consecutive days of treatment, all the mice were sacrificed on day 5, and skin tissues were resected from the back of mice followed by preparation of paraffin sections. Hematoxylin-eosin (HE) staining was performed to measure the epidermal thickness, and proliferating cell nuclear antigen (PCNA) staining was conducted to detect proliferating cells in the epidermis. Two-way analysis of variance and one-way analysis of variance were used for comparisons among groups, and least significant difference- t test was used for multiple comparisons. Results:No significant difference in the epidermal thickness or number of PCNA-positive cells was observed between the SNAP group and normal control group ( t=0.33, 1.25, P=0.748, 0.246, respectively) . Compared with the corresponding normal control groups, the barrier-impaired groups showed significantly increased epidermal thickness and number of PCNA-positive cells (all P < 0.01) . Compared with the corresponding barrier-impaired groups, SNAP-treated barrier-impaired group and SNP-treated barrier-impaired group both showed significantly increased epidermal thickness (SKH1: 127.5 ± 12.0 μm vs. 50.4 ± 5.4 μm; C57BL/6J: 78.1 ± 7.6 μm vs. 45.9 ± 3.7 μm; both P < 0.001) and number of PCNA-positive cells (SKH1: 120.0 ± 5.0 cells/mm vs. 87.3 ± 3.8 cells/mm; C57BL/6J: 285.0 ± 15.0 cells/mm vs. 232.0 ± 19.3 cells/mm; both P < 0.01) . Conclusion:Topical nitric oxide donors did not affect normal epidermis, but could aggravate epidermal hyperplasia in barrier-impaired skin, suggesting that skin condition affects the effect of topical nitric oxide donors on epidermal hyperplasia.

Pharmacokinetics of two types of dipropofol crystal tablets in Beagle dogs / 药学学报

A method for determining dipropofol in the plasma of Beagle dogs was established by HPLC-MS/MS. We also studied the pharmacokinetic characteristics of two different forms of crystal tablets of dipropofol in Beagle dogs. All animal experiments were approved by the Animal Experimental Management, Welfare and Ethics Committee of Pharmacology Evaluation Research Center, Shanghai Institute of Pharmaceutical Industry. The results indicate that the maximum plasma concentration (Cmax) of dipropofol was 69.02 ± 20.16 μg·L-1 after 20 mg·kg-1 crystal form Ⅰ tablet taken orally, and the AUC0-t was 160.49 ± 55.26 μg·L-1·h. After 20 mg·kg-1 crystal form Ⅱ tablet taken, the Cmax of dipropofol was 92.58 ± 60.26 μg·L-1, and the AUC0-t was 243.59 ± 148.36 μg·L-1·h. The AUC0-t and Cmax of crystal form Ⅱ were significantly different from that of crystal form Ⅰ (P<0.05). Crystal form Ⅱ was the dominant crystal form. The results suggest that we should control crystal form during the development of dipropofol oral tablets.

Study on 4 weeks medium intensity aeraobic exercise induce the difference expression of the proteomics in rat atrial muscle / 中国应用生理学杂志

OBJECTIVE@#To investigate the effect of moderate-intensity aerobic exercise on the differential expression of rat atrial muscle Proteomics and genes, which provide research basis for the rehabilitation of chronic cardiovascular diseases and exercise -induced cardiac remodeling research.@*METHODS@#Twenty male SD rats were randomly divided into control group and experimental group (=10) according to body weight. Rats in the experimental group were trained (6 days per week),which lasted for 4 weeks of moderate-intensity aerobic exercise at a rate of 24 m·min for 40 min (load intensity equivalent to 60%~70% VO). The proteins were separated by two dimensional gel electrophoresis, and the tandem time-of- flight mass spectrometer technique was used to identify 13 candidate target protein spots. The expression levels of these 13 protein spots were up-regulated more than 5 times or down -regulated to below 1/5. The mRNA of six target proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR).@*RESULTS@#By software analysis, the experimental group compared with the control group, there were 8 protein points which their expression reduced more than 4/5 and 5 protein points up-regulated more than 5 times, 13 proteins were identified by mass spectrometry protein spots, the final identification results acquired 8 proteins and a unknown protein of molecular mass 54 KDa, such as:pyruvate dehydrogenase E1α1, mitochondrial aconitate hydratase, protein disulfide isomerase A3, methylmalonic acid semialdehyde dehydrogenase, mitochondrial dihydrolipoic acid dehydrogenase, isovaleryl coenzyme A dehydrogenase, glutathione synthetase, mitogen-activated protein kinase 3 and so on. Compared with the control group, the mRNA expression of methylmalonic acid semialdehyde dehydrogenase in the atrial muscle of rats was decreased after 4 weeks of moderate aerobic exercise (0.05); The mRNA expression level of isopentenyl-CoA dehydrogenase was increased (>0.05). The results indicated that the mRNA expression level was not completely consistent with the changes in mass spectrometry identification results.@*CONCLUSIONS@#The 4 weeks moderate-intensity aerobic exercise induced ignificant changes of rats atrial muscle protemics. The majority of the 13 identified target proteins in this experiment are energy metabolism enzymes. The majority of the expression of the target protein and the mRNA expression in the atrial muscle is inconsistent and different. Exercise may affect the regulation of gene transcription or downstream translation and modification of these target proteins, resulting in the change of differential expression.

Application of dynamic mesh technique in the development process of atherosclerosis by numerical simulation / 医用生物力学

Objective In the computational fluid dynamics software FLUENT, the independently developed user defined function (UDF) dynamic mesh program is called to achieve the mobile update of grid note based on the wall shear stress (WSS). Then this method is applied to simulate the development process of atherosclerosis (AS). Methods The UDF program by secondary development could extract WSS results of every note on the wall during the computing process, and if the threshold value criterion condition was met, the node would be adjusted to a new position. The mesh regeneration method combining with the spring smoothing and the local remeshing was adopted to control the update of the grid, so as to ensure the grid quality during deformation. Results The UDF program successfully extracted the WSS and arranged the corresponding deformation for the grid. The morphology of local extension in the proximal part and restenosis in the distal end were resulted from the vortex in the rear of the initial stenosis. Those features were similar to the indication of clinical angiography. Conclusions The independently developed UDF program has reached the expected effects, depicting the topography characteristics of AS influenced by WSS. In future researches, more influential factors should be considered in dynamic mesh deformation control to provide numerical references for clinical prognosis and risk evaluation of AS.

Diagnostic Value of Combined Detection of IAA, ICA and GADA in the Classification of Diabetes Mellitus / 现代生物医学进展

Objective:To study the diagnostic value of combined detection of IAA,ICA and GADA in the classification of diabetes mellitus.Methods:30 cases of patients with type 1 diabetes who were treated in our hospital from June 2015 to June 2016 were selected as A group,60 cases of patients with type 2 diabetes were selected as B group,50 cases of healthy people were selected as C group.The IAA,ICA and GADA of the three groups were detected by ELISA,and the positive rate of the three groups were compared.Results:The fasting glucose of A group was (10.12± 3.68) mmol/L,B group was (11.23± 3.26) mmol/L,A group and B group were significantly higher than that of C group (P＜0.05),but there was no significant difference between A group and B group (P＞0.05);the positive rates of GADA,ICA and IAA in A group and B group were significantly higher than those in C group (P＜0.05),and the positive rates of GADA,ICA and IAA in A group were significantly higher than those in B group (P＜0.05);the sensitivity and specificity of combined detection of IAA,ICA and GADA in type 2 and type 1 diabetes mellitus were significantly higher than that in the single test (P＜0.05).Conclusions:The combined detection of IAA,ICA and GADA has a high diagnostic value in the classification of diabetes mellitus,which is worth clinical application.

Protective role of serum-free supernatant of human placental fetal mesenchymal stem cells against oxidative stress injury to lung epithelial cells / 中国组织工程研究

BACKGROUND: Preliminary experimental studies have shown that the supernatant of human placental fetal mesenchymal stem cells (fPMSCs) has a certain ability to scavenge reactive oxygen species and itself has a certain antioxidant enzyme activity. OBJECTIVE: To investigate the protective role and mechanism of fPMSCs supernatant in serum-free culture on oxidative stress-injured lung epithelial cells. METHODS: Different concentrations of hydrogen peroxide produced oxygen stimulation to lung epithelial cell lines A549 for 6, 12, 24 hours, and the survival rate of lung epithelial cells was detected using cell counting kit-8 method. When the survival rate of lung epithelial cells was 50%, the concentration of hydrogen peroxide was most suitable to make an oxidative damage model. The validity of the model was verified using Hocheest33258 staining and western blot. fPMSCs were cultured in serum-free culture medium, and the supernatant of passage 3 cells was collected. Afterwards, the injured lung epithelial cells were cultured in the fPMSCs cell supernatant for 24 hours. Meanwhile, injury group (oxidative damage only) and vitamin C group (100 μmol/L vitamin C was added in the medium) were established. In the three groups, cell apoptosis was detected by flow cytometry; and western blot was used to detect apoptosis-related proteins and proteins related to the Nrf2-Keap1-ARE signaling pathway. RESULTS AND CONCLUSION: After oxygen stimulation by 600 μmol/L hydrogen peroxide for 24 hours, the survival rate of A549 cells was (56.41±3.31)% as ascertained by the cell counting kit-8 assay. Findings from Hocheest33258 staining and western blot further confirmed the reliability of this model. Flow cytometry results showed that the apoptosis rate in the vitamin C group and the supernatant group decreased to some extent compared with the injury group, and the difference between the supernatant group and the injury group was statistically significant (P < 0.05). In addition, the expression of Bax significantly decreased and the expression of Bcl-2 significantly increased in the vitamin C group and the supernatant group as detected by western blot assay, in comparison with the injury group (P < 0.05). Compared with the injury group, the expression of Nrf2 protein increased and the expression of Keap1 decreased in the vitamin C group and the supernatant group (P < 0.05). These findings suggest that fPMSCs supernatant has a certain antioxidant capacity, and may attenuat oxidative damage and inhibit apoptosis in A549 cells. The mechanism is probably related to the Nrf2-Keap1-ARE signaling pathway.

Study on the regulatory effects of mechano growth factor on soft tissue repair / 生物医学工程学杂志

Mechano growth factor (MGF) is an autocrine/paracrine factor and sensitive to mechanical stimulation. MGF can be highly expressed in various soft tissues under physical stimuli, biochemistry stimuli or in damaged situation. MGF may "compensate" the stress for tissue in the processing of tissue repair. MGF can effectively accelerate the repair of the soft tissue by promoting the proliferation, migration and differentiation of cells. This paper summarizes the MGF expressions in different soft tissues and their functions in soft tissue repair. The paper also discusses current problems and challenges in using MGF to repair the soft tissue.

Analysis of the platelet counting difference between optical method and electrical impedance method and the alarm information of instrument / 国际检验医学杂志

Objective To compare the differences of platelet(PLT) count between the optical method (PLT‐O) and electrical impedance method (PLT‐I) ,using microscopic method (PLT‐M) as a standard method ,and to analyze the alarm information of in‐strument .Methods Both of PLT‐O and PLT‐M of 468 cases of patient specimens were detected by Sysmex XE‐2100 automatic hematocyte analyzer ,and which were compared with PLT‐M .The counts and morphology of red blood cells and platelets were de‐tected by microscopic method .The alarm information of red blood cells and platelets were recorded .Results In non‐hematopathy group ,there was no significant difference among PLT‐M ,PLT‐I and PLT‐O (P=0 .071) .In hematopathy group ,PLT‐I was signifi‐cantly different from both PLT‐M and PLT‐O (P0 .05) .There were 149 cases occurring platelets alarm and 127 cases occurring red blood cells alarm in hematopathy group , which was consistent with the results of microscopic method .Conclusion When the value of PLT is below the normal reference range ,counting error of PLT‐I is large and the value of PLT should be rechecked or corrected using PLT‐M and PLT‐O .Re‐exam‐ination should be performed when alarm information is displayed .