The Arabidopsis expansin gene (AtEXPA18) is capable to ameliorate drought stress tolerance in transgenic tobacco plants

Molecular Biology Reports - Expansins are cell wall proteins loosening plant cell in pH-dependent manner. This study aimed to investigate the role of AtEXPA18 in different morphological,...     

Valveless pumping behavior of the simulated embryonic heart tube as a function of contractile patterns and myocardial stiffness

Biomechanics and Modeling in Mechanobiology - During development, the heart begins pumping as a valveless multilayered tube capable of driving blood flow throughout the embryonic vasculature. The...     

Theory for designing mechanically stable single- and double-walled SiGe nanopeapods

Journal of Molecular Modeling - The adsorption and inhibition mechanism of chain length increase and group substitution of imidazole tetrafluoroborate derivatives for the corrosion inhibition of...     

A protective effect of curcumin on cardiovascular oxidative stress indicators in systemic inflammation induced by lipopolysaccharide in rats

ObjectiveInflammation has been considered as an important factor in cardiovascular diseases (CVD). Curcumin has been well known for its anti-inflammatory effects. In current research, protective effect of curcumin on cardiovascular oxidative stress indicators in systemic inflammation induced by lipopolysaccharide (LPS) was investigated in rats.Material and methodsThe animals were divided into five groups and received the treatments during two weeks [1]: Control in which vehicle was administered instead of curcumin and saline was injected instead of LPS [2], LPS group in which vehicle of curcumin plus LPS (1 mg/kg) was administered [3-5], curcumin groups in them three doses of curcumin (5, 10 and 15 mg/kg) before LPS were administered.ResultsAdministration of LPS was followed by an inflammation status presented by an increased level of white blood cells (WBC) (p < 0.001). An oxidative stress status was also occurred after LPS injection which was presented by an increased level of malondialdehyde (MDA) while, a decrease in thiols, superoxide dismutase (SOD) and catalase(CAT) in all heart, aorta and serum (p < 0.001). The results also showed that curcumin decreased WBC (doses: 10 and 15 mg/kg) (p < 0.001) accompanying with a decrease in MDA (P < 0.01 and P < 0.001). Curcumin also improved the thiols and the activities of SOD and catalase (P < 0.05, P < 0.01 and P < 0.001).ConclusionBased on our findings, curcumin can ameliorates oxidative stress and inflammation induced by LPS in rats to protect the cardiovascular system.     

A multibody modelling approach to determine load sharing between passive elements of the lumbar spine

The human spinal segment is an inherently complex structure, a combination of flexible and semi-rigid articulating elements stabilised by seven principal ligaments. An understanding of how mechanical loading is shared among these passive elements of the segment is required to estimate tissue failure stresses. A 3D rigid body model of the complete lumbar spine has been developed to facilitate the prediction of load sharing across the passive elements. In contrast to previous multibody models, this model includes a non-linear, six degrees of freedom intervertebral disc, facet bony articulations and all spinal ligaments. Predictions of segmental kinematics and facet joint forces, in response to pure moment loading (flexion–extension), were compared to published in vitro data. On inclusion of detailed representation of the disc and facets, the multibody model fully captures the non-linear flexibility response of the spinal segment, i.e. coupled motions and a mobile instantaneous centre of rotation. Predicted facet joint forces corresponded well with reported values. For the loading case considered, the model predicted that the ligaments are the main stabilising elements within the physiological motion range; however, the disc resists a greater proportion of the applied load as the spine is fully flexed. In extension, the facets and capsular ligaments provide the principal resistance. Overall patterns of load distribution to the spinal ligaments are in agreement with previous predictions; however, the current model highlights the important role of the intraspinous ligament in flexion and the potentially high risk of failure. Several important refinements to the multibody modelling of the passive elements of the spine have been described, and such an enhanced passive model can be easily integrated into a full musculoskeletal model for the prediction of spinal loading for a variety of daily activities.     

Biomechanical evaluation of porous biodegradable scaffolds for revision knee arthroplasty

Tibial bone defect is a critical problem for revision knee arthroplasty. Instead of using metallic spacer or cement, biodegradable scaffolds could be an alternative solution. A numerical model of a revision knee arthroplasty was thus developed to estimate the mechanical resistance of the scaffold in this demanding situation. The tibia, scaffold, and prosthesis were represented by simplified parameterised geometries. The maximal gait cycle force was applied asymmetrically to simulate a critical loading. Several parameters were analysed: 1) inter-individual variability, 2) cortical bone stiffness, 3) cortical bone thickness, 4) prosthesis fixation quality, and 5) scaffold thickness. The calculated scaffold strain was compared to its experimental ultimate strain. Among the tested parameters, failure was only predicted with scaffold thickness below 5 mm. This study suggests that biodegradable bone scaffolds could be used to fill bone defects in revision knee arthroplasty, but scaffold size seems to be the limiting factor.     

Large-scale purification of recombinant hepatitis B surface antigen from Pichia pastoris with non-affinity chromatographic methods as a substitute to immunoaffinity chromatography

Abstract

The costly media, inconsistent ligand density, ligand leakage, and possible destabilization of recombinant hepatitis B surface antigen (rHBsAg) particles are main drawbacks of using immunoaffinity chromatography (IAF) in the large-scale downstream processing. In this study, we aimed to use an efficient large-scale purification system as an alternative purification method for immunoaffinity chromatography. For this purpose, we suggested integrating non-affinity chromatographic methods of hydrophobic interaction chromatography (HIC) and size-exclusion chromatography (SEC) for cost-effective purification of rHBsAg expressed in P. pastoris. The optimization of such process is not trivial and straightforward since diverse molecular characteristics of expressed rHBsAg in each type of host cell cause different interactions in non-affinity chromatography processes. The working buffer composition and chromatography parameters are the most influential factors in hydrophobic interaction chromatography. The best result for lab-scale HIC was achieved by using ammonium sulfate buffer in 10% of saturation concentration in pH 7.0 with Butyl-S Sepharose 6 Fast Flow medium and with subsequent Tween-100 and urea elution. In this process, the recovery, purity, and total yield were about 84%, 82%, and 69%, respectively. By scaling-up the HIC and integrating it with Sephacryl S-400?SEC, we obtained highly pure, i.e.,?>?90%, rHBsAg virus-like particles (VLP).     

Erythropoietin Receptor Expression Is a Potential Prognostic Factor in Human Lung Adenocarcinoma

Recombinant human erythropoietins (rHuEPOs) are used to treat cancer-related anemia. Recent preclinical studies and clinical trials, however, have raised concerns about the potential tumor-promoting effects of these drugs. Because the clinical significance of erythropoietin receptor (EPOR) signaling in human non-small cell lung cancer (NSCLC) also remains controversial, our aim was to study whether EPO treatment modifies tumor growth and if EPOR expression has an impact on the clinical behavior of this malignancy. A total of 43 patients with stage III–IV adenocarcinoma (ADC) and complete clinicopathological data were included. EPOR expression in human ADC samples and cell lines was measured by quantitative real-time polymerase chain reaction. Effects of exogenous rHuEPOα were studied on human lung ADC cell lines in vitro. In vivo growth of human ADC xenografts treated with rHuEPOα with or without chemotherapy was also assessed. In vivo tumor and endothelial cell (EC) proliferation was determined by 5-bromo-2’-deoxy-uridine (BrdU) incorporation and immunofluorescent labeling. Although EPOR mRNA was expressed in all of the three investigated ADC cell lines, rHuEPOα treatment (either alone or in combination with gemcitabine) did not alter ADC cell proliferation in vitro. However, rHuEPOα significantly decreased tumor cell proliferation and growth of human H1975 lung ADC xenografts. At the same time, rHuEPOα treatment of H1975 tumors resulted in accelerated tumor endothelial cell proliferation. Moreover, in patients with advanced stage lung ADC, high intratumoral EPOR mRNA levels were associated with significantly increased overall survival. This study reveals high EPOR level as a potential novel positive prognostic marker in human lung ADC.     

The Effect of Antimicrobial Peptide Temporin-Ra on Cell Viability and Gene Expression of Pro-inflammatory Factors in A549 Cell Line

Antimicrobial peptide Temporin-Ra was isolated from the skin secretions of marsh frog Rana ridibunda. Temporin-Ra was chemically synthesized and purified using RP-HPLC technique. The cytotoxicity of peptide on lung airway epithelial cell line (A549) and peripheral blood mononuclear cells (PBMC) was studied by MTT assay. Furthermore, the effect of Temporin-Ra on the expression of pro-inflammatory factors such as IL-1β and IL-8 in A549 cell line was evaluated at peptide concentrations of 15, 30 and 50 μg/mL for 6, 12 and 24 h using semi-quantitative RT-PCR and real-time PCR methods. The result of our experiments revealed that Temporin-Ra decreased cell viability about 3–13 % in A549 cells and 4–6 % in PBMC cells. Moreover, Temporin-Ra induced the mRNA expression of IL-1β and IL-8 genes in a dose- and time-dependent manner. According to our results, maximum IL-8 mRNA expression was observed after a 24-h treatment of cancer cells with 50 μg/mL peptide with approximately 18-fold increase in expression. The least expression level of IL-1β was observed after 6-h of incubation in the presence of 15 μg/mL peptide with 2.5-fold increase in expression whereas the most expression level was obtained following 24 h-treatment with 50 μg/mL peptide with 26-fold increase in mRNA expression. Eventually, the present study highlights the role of Temporin-Ra as a potent antimicrobial peptide in the activation and maintenance of inflammatory processes.