Investigation of Viscoelastic Guided Wave Properties in Anisotropic Laminated Composites Using a Legendre Orthogonal Polynomials Expansion-Assisted Viscoelastodynamic Model.

This study investigates viscoelastic guided wave properties (e.g., complex-wavenumber-, phase-velocity-, and attenuation-frequency relations) for multiple modes, including different orders of antisymmetric, symmetric, and shear horizontal modes in viscoelastic anisotropic laminated composites. To obtain those frequency-dependent relations, a guided wave characteristic equation is formulated based on a Legendre orthogonal polynomials expansion (LOPE)-assisted viscoelastodynamic model, which fuses the hysteretic viscoelastic model-based wave dynamics and the LOPE-based mode shape approximation. Then, the complex-wavenumber-frequency solutions are obtained by solving the characteristic equation using an improved root-finding algorithm, which leverages coefficient matrix determinant ratios and our proposed local tracking windows. To trace the solutions on the dispersion curves of different wave modes and avoid curve-tracing misalignment in regions with phase-velocity curve crossing, we presented a curve-tracing strategy considering wave attenuation. With the LOPE-assisted viscoelastodynamic model, the effects of material viscosity and fiber orientation on different guided wave modes are investigated for unidirectional carbon-fiber-reinforced composites. The results show that the viscosity in the hysteresis model mainly affects the frequency-dependent attenuation of viscoelastic guided waves, while the fiber orientation influences both the phase-velocity and attenuation curves. We expect the theoretical work in this study to facilitate the development of guided wave-based techniques for the NDT and SHM of viscoelastic anisotropic laminated composites.

Dietary α-lipoic acid can alleviate the bioaccumulation, oxidative stress, cell apoptosis, and inflammation induced by lead (Pb) in Channa argus.

This study aims to evaluate the effects of dietary α-lipoic acid (α-LA) on bioaccumulation, oxidative stress, apoptosis, and inflammation in Channa argus after 28 d of lead (Pb) exposure. A total of 300 fish were divided into five groups: the first group was the control group and the other four groups were exposed to waterborne Pb (800 ppb) and fed α-LA diets supplemented with 0, 300, 600, and 900 mg/kg. The results demonstrated that dietary α-LA effectively reduced the Pb accumulation in the liver, kidney, gill, intestine, and muscle of C. argus after exposure to Pb. Meanwhile, dietary α-LA reversed alterations in the biochemical parameters (Alanine aminotransferase (ALT), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), blood urea nitrogen (BUN), cortisol (COR), and creatinine (CRE)) and immunity parameters (myeloperoxidase (MPO), complement 3 (C3), lysozyme (LYS), complement 4 (C4), C-reactive protein (CRP), and immunoglobulin M (IgM)) in the serum of fish caused by Pb. Pb-induced reduction of antioxidant enzyme activities (Catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px)) was inhibited by dietary α-LA. And malondialdehyde (MDA) and protein carbonyl (PC) content exhibited an opposite trend. Meanwhile, dietary supplemented with α-LA was found to relieve Pb-induced oxidative stress by downregulating Keap1 mRNA expression levels and upregulating the expression levels of CAT, nuclear factor erythroid 2-related factor 2 (Nrf2), GSH-Px, and Cu/Zn SOD. Furthermore, α-LA supplementation reversed Pb-induced upregulation of pro-inflammatory genes (interleukin (IL)-6, IL-1ß, tumor necrosis factor α (TNF-α), and nuclear factor kappa B (NF-κB)), Pro-apoptotic genes (Bcl-2-associated X (Bax), caspase (Cas)-3, and tumor protein p53 (p53)) and Hsp70, and downregulation of anti-inflammatory genes (IL-10, inhibitor of κBα (IκBα), and transforming growth factor ß (TGF-ß)) and anti-apoptosis gene (B-cell lymphoma-2 (Bcl-2)). Overall, dietary α-LA supplementation could enhance the innate immunity and antioxidant capacity of fish, attenuating the Pb accumulation, and cell apoptosis after being exposed to Pb. Furthermore, dietary α-LA could relieve Pb-induced inflammatory response and oxidative stress of fish via regulating NF-κB and Nrf2 signaling, respectively.

Neuroanatomical Changes Underlying Vertical HIV Infection in Adolescents.

Purpose: The aim of this study was to investigate how human immunodeficiency virus (HIV) affects brain development in adolescents, what are susceptible brain regions, and how these brain structural changes correlate with cognitive abilities. Methods: We used structural magnetic resonance imaging to examine gray matter volume and cortical thickness in 16 HIV-infected children (mean age = 13.63 years) and 25 HIV-exposed uninfected children (mean age = 13.32 years), 12 of them were subjected to a 1-year repetitive magnetic resonance scan of the brain. Five neurocognitive tests were performed on each subject to assess cognitive performance in different areas. Results: Cross-sectional studies showed that the gray matter volume of HIV-infected children was widely reduced (mainly in the bilateral frontal, temporal, and insular regions, and cerebellum). The changes in cortical thickness were mainly due to thinning of the right temporal lobe and thickening of the left occipital lobe. Longitudinal studies showed that the gray matter volume reduction of HIV-infected children after 1 year mainly occurs in the advanced functional area of the right prefrontal, parietal lobe and the motor area, cortical thinning of brain regions were sensorimotor cortex and the limbic system. The gray matter volume of the bilateral cerebellum was positively correlated with the performance of the Wisconsin Card Sorting Test, while the cortical thickness of the right dorsolateral prefrontal cortex was negatively correlated with this test. Conclusion: This study found that HIV-infected pubertal children showed a delayed cortical maturation with atrophy. This abnormal pattern of cortical development may be the structural basis for cognitive impairment in HIV-infected children.

Inhibition of Phosphoglycerate Mutase 5 Reduces Necroptosis in Rat Hearts Following Ischemia/Reperfusion Through Suppression of Dynamin-Related Protein 1.

PURPOSE: Necroptosis is an important form of cell death following myocardial ischemia/reperfusion (I/R) and phosphoglycerate mutase 5 (PGAM5) functions as the convergent point for multiple necrosis pathways. This study aims to investigate whether inhibition of PGAM5 could reduce I/R-induced myocardial necroptosis and the underlying mechanisms. METHODS: The SD rat hearts (or H9c2 cells) were subjected to 1-h ischemia (or 10-h hypoxia) plus 3-h reperfusion (or 4-h reoxygenation) to establish the I/R (or H/R) injury model. The myocardial injury was assessed by the methods of biochemistry, H&E (hematoxylin and eosin), and PI/DAPI (propidium iodide/4',6-diamidino-2-phenylindole) staining, respectively. Drug interventions or gene knockdown was used to verify the role of PGAM5 in I/R (or H/R)-induced myocardial necroptosis and possible mechanisms. RESULTS: The I/R-treated heart showed the injuries (increase in infarct size and creatine kinase release), upregulation of PGAM5, dynamin-related protein 1 (Drp1), p-Drp1-S616, and necroptosis-relevant proteins (RIPK1/RIPK3, receptor-interacting protein kinase 1/3; MLKL, mixed lineage kinase domain-like); these phenomena were attenuated by inhibition of PGAM5 or RIPK1. In H9c2 cells, H/R treatment elevated the levels of PGAM5, RIPK1, RIPK3, MLKL, Drp1, and p-Drp1-S616 and induced mitochondrial dysfunctions (elevation in mitochondrial membrane potential and ROS level) and cellular necrosis (increase in LDH release and the ratio of PI+/DAPI+ cells); these effects were blocked by inhibition or knockdown of PGAM5. CONCLUSIONS: Inhibition of PGAM5 can reduce necroptosis in I/R-treated rat hearts through suppression of Drp1; there is a positive feedback between RIPK1 and PGAM5, and PGAM5 might serve as a novel therapeutic target for prevention of myocardial I/R injury.

Vascular peroxide 1 promotes ox-LDL-induced programmed necrosis in endothelial cells through a mechanism involving ß-catenin signaling.

BACKGROUND AND AIMS: Vascular peroxidase 1 (VPO1) plays a key role in mediation of cardiovascular oxidative injury. This study aims to determine whether VPO1 can promote programmed necrosis of endothelial cells and the underlying mechanisms. METHODS AND RESULTS: Human umbilical vein endothelial cells (HUVECs) were incubated with oxidized low-density lipoprotein (ox-LDL, 100 µg/mL) for 48 h to induce cell injury, which showed an elevation in cell necrosis (reflected by the increased propidium iodide (PI) positive-staining cells, LDH release and decreased cell viability), concomitant with an increase in programmed necrosis-relevant proteins including receptor-interacting protein kinase 1/3 (RIPK1/3), p-RIPK3 and mixed lineage kinase domain like (MLKL); these phenomena were attenuated by necrostatin-1(Nec-1) and RIPK3 siRNA. Meanwhile, VPO1 was up-regulated in ox-LDL-treated endothelial cells accompanied by a decrease in GSK-3ß activity and p-ß-catenin levels, and an elevation of ß-catenin levels; these phenomena were reversed in the presence of VPO1 siRNA or hypochlorous acid (HOCl) inhibitor; replacement of ox-LDL with HOCl could also induce endothelial programmed necrosis and activate the ß-catenin signaling; ß-catenin inhibitor could also suppress ox-LDL-induced RIPK-dependent necrosis. In hyperlipidemic patients, the plasma level of VPO1 was obviously increased concomitant with an elevation in plasma levels of RIPK1, RIPK3 and MLKL, and they were positively correlated. CONCLUSIONS: VPO1 plays an important role in promotion of endothelial programmed necrosis under hyperlipidemic conditions through activation of ß-catenin signaling. It may serve as a novel therapeutic target for prevention of endothelial dysfunction in hyperlipidemia.

Correlation between NADPH oxidase-mediated oxidative stress and dysfunction of endothelial progenitor cell in hyperlipidemic patients.

BACKGROUND/AIMS: NADPH (nicotinamide adenine dinucleotide phosphate) oxidase (NOX)-mediated oxidative stress plays a key role in promotion of oxidative injury in the cardiovascular system. The aim of this study is to evaluate the status of NOX in endothelial progenitor cells (EPCs) of hyperlipidemic patients and to assess the correlation between NOX activity and the functions EPCs. METHODS: A total of 30 hyperlipidemic patients were enrolled for this study and 30 age-matched volunteers with normal level of plasma lipids served as controls. After the circulating EPCs were isolated, the EPC functions (migration, adhesion and tube formation) were evaluated and the status of NOX (expression and activity) was examined. RESULTS: Compared to the controls, hyperlipidemic patients showed an increase in plasma lipids and a reduction in EPC functions including the attenuated abilities in adhesion, migration and tube formation, concomitant with an increase in NOX expression (NOX2 and NOX4), NOX activity, and reactive oxygen species production. The data analysis showed negative correlations between NOX activity and EPC functions. CONCLUSIONS: There is a positive correlation between the NOX-mediated oxidative stress and the dysfunctions of circulating EPCs in hyperlipidemic patients, and suppression of NOX might offer a novel strategy to improve EPCs functions in hyperlipidemia.

Atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats through a mechanism involving down-regulation of miR-21-5p/203a-3p.

Statins are reported to exert benefits on endothelial function through a mechanism involving in prevention of endothelial senescence. This study aims to explore whether atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats or ox-LDL-treated HUVECs through a mechanism involving suppress of miR-21-5p/203a-3p expression and their downstream pathway. The rats were fed with high-fat diet to establish a hyperlipidemic model, which showed an increase in plasma lipids and endothelial senescence, accompanied by the elevation in plasma levels of miR-21-5p/203a-3p, down-regulation of Drp1 and up-regulation of p53 in the aorta of hyperlipidemic rats; these phenomena were reversed by atorvastatin. Next, HUVECs were incubated with ox-LDL to establish a senescent model in vitro. Consistent with the finding in vivo, atorvastatin treatment decreased the level of miR-21-5p and miR-203a-3p in the ox-LDL-treated HUVECs, restored Drp1 expression and mitochondrial function, as well as suppressed p53 and p16 expression and endothelial senescence. Based on these observations, we conclude that atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats through a mechanism involving down-regulation of miR-21-5p/203a-3p, which leads to the restoration of Drp1 level and recovery of mitochondrial function. Our findings highlight a novel non-lipid effect for atorvastatin besides its function in modulation of lipids.

Comparison of autogenous tendon reconstruction with coracoclavicular ligament combined with hook plate and simple hook plate fixation in the treatment of acromioclavicular joint dislocation / 中国组织工程研究

BACKGROUND: Hook plate is usual and satisfactory for the treatment of acromioclavicular joint dislocation, but there are still many problems. The comparative analysis is seldom reported between reconstruction of coracoclavicular ligament by autogenous tendon combined with hook plate and simple hook plate. OBJECTIVE: To compare the clinical efficacy of reconstruction of coracoclavicular ligament combined with hook plate and simple hook plate fixation for acromioclavicular joint dislocation. METHODS: A total of 38 patients with acromioclavicular dislocation were randomly divided into two groups. The patients were treated with plantar tendon "V" reconstruction with coracoclavicular ligament combined with hook plate fixation (combination group) and with a simple hook plate fixation (simple hook plate group). We compared the operation time, blood loss, hospitalization days, average hospitalization costs, the time taken for internal fixation, the motion range of shoulder joint at postoperative 12 months, the Constant-Murley function score, the reduction of shoulder joint and the Visual Analogue Scale scores between the two groups. RESULTS AND CONCLUSION: (1) Patients in both groups were followed up for 12 months. In the combination group, the hook plate was removed at postoperative 3 months. In the simple hook plate group, the hook plate was removed at approximately postoperative 12 months. In follow-up, no dislocation appeared in both groups. (2) No significant difference in hospitalization days, motion range of shoulder joint, Constant-Murley function score, the reduction of shoulder joint and the Visual Analogue Scale scores was determined between the two groups (P > 0.05). (3) Operation time was longer; blood loss was more; and average hospitalization costs were higher in the combination group than in the simple hook plate group (P < 0.05). (4) These findings indicate that plantar tendon reconstruction of coracoclavicular ligament combined with hook plate meets biomechanical requirements in the treatment of acromioclavicular joint dislocation. The plate can be removed early using a fixator. The lower extremity has an incision, but the follow-up results are satisfactory. Simple hook plate fixation for acromioclavicular joint dislocation takes a long time, and can obtain average effect, but there is the risk of re-dislocation (this case does not experience re-dislocation). The appropriate treatment can be chosen according to the patient's condition, needs, and economic conditions.

Correlation between NADPH oxidase-mediated oxidative stress and dysfunction of endothelial progenitor cell in hyperlipidemic patients

BACKGROUND/AIMS: NADPH (nicotinamide adenine dinucleotide phosphate) oxidase (NOX)-mediated oxidative stress plays a key role in promotion of oxidative injury in the cardiovascular system. The aim of this study is to evaluate the status of NOX in endothelial progenitor cells (EPCs) of hyperlipidemic patients and to assess the correlation between NOX activity and the functions EPCs. METHODS: A total of 30 hyperlipidemic patients were enrolled for this study and 30 age-matched volunteers with normal level of plasma lipids served as controls. After the circulating EPCs were isolated, the EPC functions (migration, adhesion and tube formation) were evaluated and the status of NOX (expression and activity) was examined. RESULTS: Compared to the controls, hyperlipidemic patients showed an increase in plasma lipids and a reduction in EPC functions including the attenuated abilities in adhesion, migration and tube formation, concomitant with an increase in NOX expression (NOX2 and NOX4), NOX activity, and reactive oxygen species production. The data analysis showed negative correlations between NOX activity and EPC functions. CONCLUSIONS: There is a positive correlation between the NOX-mediated oxidative stress and the dysfunctions of circulating EPCs in hyperlipidemic patients, and suppression of NOX might offer a novel strategy to improve EPCs functions in hyperlipidemia.

Advance in research on causative genes of xeroderma pigmentosum and related diseases / 中华医学遗传学杂志

Ultraviolet light(UV)-sensitive disorders refer to a group of diseases due to damages to the nucleotide excision repair mechanism which cannot effectively repair DNA damage caused by ultraviolet radiation. The inheritance pattern of such diseases, mainly including xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy, is autosomal recessive and known to involve 13 genes. As proteins encoded by such genes are involved in DNA repair and transcription pathways. There is overlap between the symptoms of such diseases, and their genotype - phenotype correlations are quite complex. To facilitate genetic and prenatal diagnosis for such diseases, a summary of the research progress is provided, which mainly focused on mutation research and genotype - phenotype correlation studies. We also propose a strategy for their genetic diagnosis based on recent findings of our group.

Efficacy evaluation of combined anterior-lateral approach for treatment of elbow triad injuries / 中华创伤杂志

Objective To discuss the surgical techniques and results of internal fixation supplemented with soft tissue repair of triad injury of the elbow via the combined anterior-lateral approach.Methods A retrospective analysis was done on 15 patients with triad injury of the elbow treated from January 2011 to August 2014.There were 10 males and 5 females,aged 38.4 years (range,20-61 years).Injury resulted from traffic accidents in nine patients,high-level falls in three and groundlevel falls in three.Radial head fractures were Mason type Ⅰ in five patients,type Ⅱ in eight,and type Ⅲ in two.Fractures of the coronoid process of the ulna were Regan-Morrey type Ⅰ in four patients,type Ⅱ in ten and type Ⅲ in one.Time interval between injury and operation was 8.5 d.All patients were firstly operated on through the anterior approach to have Herbert screw fixation or anterior capsule suture lasso fixation of the coronoid fracture as well as Herbert screw fixation of the radial head fracture.And then,elbow lateral incision was made to repair lateral collateral ligament complex and common extensor tendon by 2-0 Ethibon suture.Elbow flexion-extension,forearm pronation-supination and Mayo elbow performance score (MEPS) were used to evaluate the clinical elbow functions.Complications were recorded after operation.Results All patients were followed up for mean 19.6 months (range,12-30 months).All coronoid fractures healed.Radial head fractures in 14 patients healed.Comparison of preoperative to final follow-up variables presented significant differences in elbow flexion-extension [(45.1 ± 5.6) °:(129.5 ± 9.3) °],forearm pronation-supination [(55.4 ±.8.7) °:(140.5 ± 10.3) °] and MEPS [(25.1 ± 9.6) points:(91.2 ± 5.2) points] (P ＜ 0.01).Complications included heterotopic ossification in one patient and nonunion of radial head fracture in one patient.No neurovascular injury of the elbow,elbow residual instability,dislocation,elbow stiffness and active pain occurred.Conclusion Combined anterior-lateral approach with internal fixation and soft tissue repair is a simple and safe method that effectively restore the elbow joint function.

Myeloperoxidase-derived hypochlorous acid promotes ox-LDL-induced senescence of endothelial cells through a mechanism involving ß-catenin signaling in hyperlipidemia.

Myeloperoxidase (MPO)-derived product hypochlorous acid (HOCl) is able to induce cellular senescence and MPO is also expressed in endothelial cells besides the well-recognized immune cells. This study aims to clarify the association of endothelium-derived MPO with endothelial senescence in hyperlipidemia. The rats were fed with high-fat diet for 8 weeks to establish a hyperlipidemic model, which showed an increase in plasma lipids, endothelium-derived MPO expression, endothelial senescence and endothelial dysfunction concomitant with a reduction in glycogen synthase kinase 3 beta (GSK-3ß) activity and phosphorylated ß-catenin (p-ß-catenin) level as well as an increase in ß-catenin and p53 levels within the endothelium. Next, human umbilical vein endothelial cells (HUVECs) were incubated with oxidized low density lipoprotein (ox-LDL, 100 µg/ml) for 24 h to establish a senescent cell model in vitro. Consistent with the finding in vivo, ox-LDL-induced MPO expression and HUVECs senescence, accompanied by a decrease in GSK-3ß activity and p-ß-catenin level as well as an increase in HOCl content, ß-catenin and p53 levels; these phenomena were attenuated by MPO inhibitor. Replacement of ox-LDL with HOCl could also induce HUVECs senescence and activate the ß-catenin/p53 pathway. Based on these observations, we conclude that endothelium-derived MPO is upregulated in hyperlipidemic rats, which may contribute to the accelerated vascular endothelial senescence through a mechanism involving the ß-catenin/p53 pathway.

Clinical use of azelnidipine in the treatment of hypertension in Chinese patients.

BACKGROUND: Hypertension is the most common chronic disease and the calcium channel antagonist is the most popularly used antihypertensive drug in Chinese patients. Azelnidipine is a third generation and long-acting dihydropyridine calcium channel antagonist. A series of research has demonstrated that azelnidipine produced an effective antihypertensive effect in patients with essential hypertension. Now it is need to summarize clinical use of azelnidipine in the treatment of hypertension in Chinese patients. METHODS: Relevant literature was identified by performing searches in PubMed and CNKI (China National Knowledge Infrastructure), covering the period from January 2003 (the year azelnidipine was launched) to July 2014. We included studies that described pharmacology of azelnidipine, especially the pharmacokinetics, clinical efficacy, and safety and tolerability of azelnidipine in a Chinese population. The full text of each article was strictly reviewed, and data interpretation was performed. RESULTS: In Chinese healthy volunteers, a single-dose oral administration of azelnidipine 8-16 mg had a peak plasma concentration of 1.66-23.06 ng/mL and time to peak plasma concentration was 2.6-4.0 hours and the area under the plasma concentration versus time curve from time 0 hour to 96 hours was 17.9-429 ng/mL·h and elimination half-life was 16.0-28.0 hours. A number of clinical trials have demonstrated that azelnidipine produced a significant reduction in blood pressure in Chinese patients with mild-to-moderate hypertension, which was similar to that of other effective antihypertensive drugs such as amlodipine, zofenopril, and nifedipine. In addition to its antihypertensive effect, azelnidipine had other cardiovascular protective effects as well, like anti-oxidative action, decreasing heart rate, and improving systolic and diastolic function. Azelnidipine was generally well tolerated in Chinese patients and no severe adverse events were observed. CONCLUSION: Azelnidipine is effective and safe in the treatment of hypertension in Chinese patients.

Non-antiplatelet effect of clopidogrel: improving endothelial function in Chinese healthy subjects with different CYP2C19 genotype.

Clopidogrel has been shown to improve endothelial function in vitro and in patients with coronary artery disease. However, it remains unclear whether such an effect of clopidogrel is associated with CYP2C19 polymorphisms that determine the antiplatelet effect of clopidogrel. After genotyping, 12 healthy participants were enrolled in the study. Among them, six participants were CYP2C19*1/*1 (extensive metabolizers; EM) and the other six participants were CYP2C19*2/*2 or *3 (poor metabolizers; PM). All participants received 300 mg clopidogel orally. Endothelial function was assessed by measurement of flow-mediated dilation of the brachial artery, and adenosine diphosphate-induced platelet aggregation was determined by using optical aggregometry at 0, 4 and 24 h after administration of 300 mg clopidogrel. Flow-mediated dilation was significantly higher at 4 and 24 h after a loading-dose administration of clopidogrel in both the CYP2C19 EM and PM groups, but showed no significant difference between the two groups. Adenosine diphosphate-induced platelet aggregation was significantly inhibited at 4 and 24 h after administration of clopidogrel in the CYP2C19 EM group. However, there was no statistical correlation between the change in flow-mediated dilation and adenosine diphosphate-induced platelet aggregation in the two CYP2C19 groups. This is the first study to report that clopidogrel improves endothelial function in healthy Chinese subjects, which is unrelated with the CYP2C19 genotype and independent of antiplatelet action.