Effects Of Different Mediators Research Articles

Effect of Different Mediators on Bio-Energy Generation and Palm Oil Mill Effluent Treatment in an Air-Cathode Microbial Fuel Cell-Adsorption System

Palm oil mill effluent (POME) discharged without treatment into watercourses can pollute the water source. Microbial fuel cell (MFC) has gained high attention as a green technology of converting organic wastewater into bio-energy. As an approach to overcome the limitations of the existing POME treatment methods, air-cathode MFC-Adsorption system is introduced as an innovative technology to treat POME and generate bio-electricity simultaneously. However, the use of conventional MFC with proton exchange membrane in large scale applications is restricted by the high cost and low power generation. Addition of mediator in MFC is essential in order to increase the electron transfer efficiency, hence enhancing the system performance. This study therefore aims to investigate the effect of different type of mediators i.e. congo red (CR), crystal violet (CV) and methylene blue (MB) on the performance of an affordable air-cathode MFC-Adsorption system made from earthen pot with POME as the substrate. The addition of different mediators altered the pH of the MFC-Adsorption system, in which more alkaline system showed better performance. The voltage generated in the system with CR, CV and MB mediator was 120.58 mV, 168.63 mV and 189.25 mV whereas the current generated was 2.41 mA, 3.37 mA and 3.79 mA, respectively. The power density of 290.79 mW/m3, 568.72 mW/m3 and 716.31 mW/m3 was produced in the MFC-Adsorption system with CR, CV and MB mediator, respectively. The highest POME treatment efficiency was achieved in MFC-Adsorption system with MB mediator, which resulted in biochemical oxygen demand, chemical oxygen demand, total suspended solids, turbidity and ammoniacal nitrogen removal of 75.3%, 84.8%, 91.5%, 86.1% and 23.31%, respectively. Overall, the air-cathode MFC-Adsorption system with addition of MB mediator was feasible for POME treatment and simultaneous bio-energy generation.

Multi-parametric Cell-Based Inflammation Assays for Cytokines and Cell Surface Antigens

Abstract Macrophages and vascular cells upregulate expression of cytokines and adhesion molecules in response to inflammation stimuli. Monitoring these molecules can provide a physiological read-out for inflammation. We present results from a multiparametric assays that used a combination of low-volume ELISA for secreted cytokines and automated cell imaging for cell surface markers to evaluate the effect of different mediators on inflammatory response with two cell models. First, human monocytic THP-1 cells were differentiated to macrophages and activated by LPS. Phenotypic changes in cell morphology were quantified by cell area and number of adherent cells using TL imaging. Secretion of IL-8, IL-1β and TNF-α was quantified by an automated low-volume ELISA (PuMA System). Second, primary human umbilical vein endothelial cells (HUVEC) were stimulated with inflammation cytokines (TNF-α, IFN-γ, and IL-1β), then PuMA System was used to quantify amount of MCP-1, IL-8, and IL-6 in cell supernatants. Expression of adhesion molecules VCAM and HLADR was quantified by measurement of total fluorescence from antibody-stained cells using an ImageXpress Pico system. Concentration dependent inhibition of inflammation by the compounds AG126 and MG132, SB202190 and PDTC were measured and EC50s calculated. Clear differences in cytokine expression were seen between the compounds consistent with reported mechanism of actions of the kinase inhibitors. The combination of imaging and microfluidic-based assays provides an efficient multiparametric assay system that can test the efficacy of anti-inflammatory compounds versus toxicity and provide insight into their MoA by selective inhibition of markers triggered by different signaling pathways.

Multi-parametric Human Cell-Based Inflammation Assay for Cytokines and Cell Surface Antigens

Abstract Inflammation is a complex event in which cells respond to various endogenous and exogenous stimuli. Factors such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-γ activate signaling pathways leading to the expression of cytokines and cell-surface antigens. The ability to monitor up-regulation of these molecules provides an important physiological read-out for cell-based models of inflammation. We present results from a multiparametric cell-based assay that uses immunoassays for secreted cytokines and fluorescence read-outs of cell surface markers to evaluate the effect of different mediators on inflammatory response. Primary human umbilical vein endothelial cells (HUVEC) were stimulated with inflammation cytokines (TNF-α, IFN-γ, and IL-1β) for 20 hours. Then, a newly developed microfluidic-based assay system, PuMA, was used to quantify amount of MCP-1, IL-8, and IL-6 in cell supernatants. Expression of adhesion molecules VCAM and HLADR was quantified by measurement of total fluorescence intensity after staining cells with directly conjugated antibodies using an ImageXpress Nano Automated Imaging System. Concentration dependent inhibition of the inflammation responses by the compounds AG126 and MG132 were measured. Clear differences in cytokine expression were seen between the compounds consistent with their reported mechanisms of action. The combination of imaging and microfluidic-based assays provides an efficient multiparametric assay system that can be used to test the efficacy of anti-inflammatory compounds versus toxicity and also provide significant insight into the mechanism of action by selective inhibition of markers triggered by different signaling pathways.

New Insights into the Immunobiology of Mononuclear Phagocytic Cells and Their Relevance to the Pathogenesis of Cardiovascular Diseases.

Macrophages are the primary immune cells that reside within the myocardium, suggesting that these mononuclear phagocytes are essential in the orchestration of cardiac immunity and homeostasis. Independent of the nature of the injury, the heart triggers leukocyte activation and recruitment. However, inflammation is harmful to this vital terminally differentiated organ with extremely poor regenerative capacity. As such, cardiac tissue has evolved particular strategies to increase the stress tolerance and minimize the impact of inflammation. In this sense, growing evidences show that mononuclear phagocytic cells are particularly dynamic during cardiac inflammation or infection and would actively participate in tissue repair and functional recovery. They respond to soluble mediators such as metabolites or cytokines, which play central roles in the timing of the intrinsic cardiac stress response. During myocardial infarction two distinct phases of monocyte influx have been identified. Upon infarction, the heart modulates its chemokine expression profile that sequentially and actively recruits inflammatory monocytes, first, and healing monocytes, later. In the same way, a sudden switch from inflammatory macrophages (with microbicidal effectors) toward anti-inflammatory macrophages occurs within the myocardium very shortly after infection with Trypanosoma cruzi, the causal agent of Chagas cardiomyopathy. While in sterile injury, healing response is necessary to stop tissue damage; during an intracellular infection, the anti-inflammatory milieu in infected hearts would promote microbial persistence. The balance of mononuclear phagocytic cells seems to be also dynamic in atherosclerosis influencing plaque initiation and fate. This review summarizes the participation of mononuclear phagocyte system in cardiovascular diseases, keeping in mind that the immune system evolved to promote the reestablishment of tissue homeostasis following infection/injury, and that the effects of different mediators could modulate the magnitude and quality of the immune response. The knowledge of the effects triggered by diverse mediators would serve to identify new therapeutic targets in different cardiovascular pathologies.

Effects of different mediators on electricity generation and microbial structure of a toluene powered microbial fuel cell

Neutral red and potassium ferricyanide are two electron mediators that can increase the efficiency of microbial fuel cells (MFCs) via significantly different mechanisms. In this study, effects of the two mediators on electricity generation and microbial structure of a toluene powered MFC was first investigated. The maximum voltage (Vmax) was 110.4mV and the half-saturation constant (Ks) was 12.8mg/L in the absence of mediators. Although the power generation efficiency was increased when adding modest amount of mediators to the anode, the toluene degradation time was 1.56–2.15 times longer than that of unmediated MFC’s, relying on the mediator used. Denaturing gradient gel electrophoresis (DGGE) analysis showed a mediator-related characteristic of the microbial structure in the MFC. Results of this investigation can be used as a basis for future assessment and design of MFCs powered by xenobiotics-contaminated wastewater, such as toluene.

Development of novel enzymatic bioremediation process for textile industry effluents through response surface methodology

Crude ligninolytic enzymes extract from Schyzohyllum commune IBL-06 having high activities of LiP (2186.02UmL−1), MnP (1676.75UmL−1) and laccase (259.07UmL−1) was used for bioremediation of textile industry effluents. Response Surface Methodology (RSM) was adopted using D-optimal design to optimize the effluent decolorization process. The effects of different mediators on effluent decolorization were also investigated under preoptimized conditions. The optimum conditions for maximum decolorization of the effluents collected from Khyber Textile (KHT), Ishaq Textile (IST), Kalash Textile (KAT) and Masood Textile (MAT) industries of Faisalabad, Pakistan were: initial pH 4.5; temperature, 35°C; effluent concentration, 180ppm and veratryl alcohol (mediator), 1mM. It was noted that values of water quality parameters including pH, color, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total organic carbon (TOC) and formaldehyde for enzyme treated effluents were within permissible limits set by the National Environmental Quality Standards (NQS). Analysis of peaks in HPLC profiles for treated and untreated effluents confirmed the degradation of residual dyes by ligninolytic enzymes extract of S. commune IBL-06.

In vitro effect of different mediators of apoptosis on canine cranial and caudal cruciate ligament fibroblasts and its reversibility by pancaspase inhibitor zVAD.fmk

Primary fibroblast cultures of canine cranial (CCL) and caudal (CaCL) cruciate ligaments were stimulated with different apoptosis inducers with or without preincubation of the pancaspase inhibitor zVAD.fmk. In contrast to CaCL fibroblasts, fibroblasts from CCL were significantly more susceptible to apoptosis inducers of the intrinsic pathway like doxorubicin, cisplatin and nitric oxide (NO)-donors and to Fas ligand (FasL), an apoptosis inducer of the death receptor pathway. Apoptotic response to staurosporine and the peroxynitrite donor GEA was similar in both ligament fibroblasts. Stimulation with dexamethasone or TNFα could not induce apoptosis in CCL and CaCL fibroblasts, in spite of present TNFR1 and TNFR2 receptors. zVAD.fmk was able to prevent apoptosis in up to 66% of CCL cells when treated with FasL, cisplatin or doxorubicin but it had no effect on NO or peroxynitrite induced apoptosis. In conclusion, differential susceptibility to apoptotic triggers like FasL or NO between cranial and caudal cruciate ligament fibroblasts in vitro may be a reflection of the different susceptibilities to degenerative rupture of the ligament. These findings indicate that a general caspase inhibition does not completely protect canine CCL cells from apoptosis.

Osteoprotegerin and the receptor activator of NF-kappa B ligand in the serum and synovial fluid. A comparison of patients with longstanding rheumatoid arthritis and osteoarthritis

We examined OPG and soluble RANKL in the serum (sOPG, sRANKL) and synovial fluid (synOPG, synRANKL) in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). OPG and RANKL were measured in 85 patients (44 with RA, 41 patients with OA) in serum and synovial fluid as well. For measuring of OPG and RANKL ELISA tests were used. The results of OPG and RANKL were compared with clinical and radiological scores. We found a negative correlation for OPG and RANKL in synovial fluids: not only for the whole group of patients (P < 0.003, r = -0.32), but also for the subgroups (RA: P < 0.04, r = -0.28, OA: P < 0.002, r = -0.54). SRANKL and synRANKL were positively correlated in the whole group (P < 0.01, r = 0.25) and in the OA group (P < 0.02, r = 0.35); the RA group was showing a trend (P < 0.063, r = 0.24), however. Serum OPG was lower in RA, synOPG higher in OA. The difference between the two patient groups was only significant for synOPG (P < 0.03, r = 0.056), but not for sOPG (P < 0.09, r = 0.19), sRANKL (P < 0.43, r = 0.85) or synRANKL (P < 0.11, r = 0.22). The synOPG:synRANKL ratio was significantly correlated with the Larsen score (P < 0.004, r = 0.38). Synovial OPG is significantly decreased in rheumatoid joints, whereby synovial RANKL is increased. Lower synOPG could reflect a lower protective effect on bone, thus leading to an earlier and more pronounced bone destruction in RA. However, the effect of different mediators for joint destruction in RA and OA seems not to be important to the pathophysiological changes in the joints. The upregulation of serum OPG might be the result of the inflammation; in contrast, an upregulation of RANKL could not be found in the serum of patients with RA and OA.

Biosensor for H2O2 Response Based on Horseradish Peroxidase: Effect of Different Mediators Adsorbed on Silica Gel Modified with Niobium Oxide

Reagentless biosensors sensitive to hydrogen peroxide have been developed and compared. These biosensors are comprised of a carbon paste electrode modified with horseradish peroxidase (HRP) and one phenothiazine (methylene blue), one phenoxazine (meldola's blue) or one phenazine (phenazine methosulfate) dye adsorbed on silica gel modified with niobium oxide (SN). The enzyme was immobilized onto the graphite powder by cross-linking with glutaraldehyde and mixing with one of the electron transfer mediators (dyes) adsorbed on SN. The amperometric response was based on the electrocatalytic properties of the dye to mediate electrons, which were generated in the enzymatic reaction of hydrogen peroxide under catalysis of HRP. The dependence on the biosensor response in terms of pH, buffer, HRP amounts and applied potential was investigated. The best results were found with a biosensor containing methylene blue dye showing an excellent operational stability (around 92% of the activity was maintained after 300 determinations). The proposed biosensor also presented good sensitivity (32.87 nA cm−2 μmol−1 L) allowing hydrogen peroxide quantification at levels down to 0.52×10−6 mol L−1 an optimum response at pH 6.8 and at a potential of −50 mV (vs. SCE) and showing a wide linear response range (from 1 to 700 μmol L−1 for hydrogen peroxide).

Microvascular dysfunction induced by reperfusion injury and protective effect of ischemic preconditioning.

Hepatic ischemia/reperfusion injury has immediate and deleterious effects on the outcome of patients after liver surgery. The precise mechanisms leading to the damage have not been completely elucidated. However, there is substantial evidence that the generation of oxygen free radicals and disturbances of the hepatic microcirculation are involved in this clinical syndrome. Microcirculatory dysfunction of the liver seems to be mediated by sinusoidal endothelial cell damage and by the imbalance of vasoconstrictor and vasodilator molecules, such as endothelin (ET), reactive oxygen species (ROS), and nitric oxide (NO). This may lead to no-reflow phenomenon with release of proinflammatory cytokines, sinusoidal plugging of neutrophils, oxidative stress, and as an ultimate consequence, hypoxic cell injury and parenchymal failure. An inducible potent endogenous mechanism against ischemia/reperfusion injury has been termed ischemic preconditioning. It has been suggested that preconditioning could inhibit the effects of different mediators involved in the microcirculatory dysfunction, including endothelin, tumor necrosis factor-alpha, and oxygen free radicals. In this review, we address the mechanisms of liver microcirculatory dysfunction and how ischemic preconditioning could help to provide new surgical and/or pharmacological strategies to protect the liver against reperfusion damage.

Effects of different mediators or cytokines and monoclonal antibodies to adhesion molecules on leukocyte adhesion in rat mesenteric venules.

Leukocyte adhesion (LA) to the endothelium of postcapillary venules is considered to be an important step in the inflammatory response. The recruitment of blood leukocytes into sites of inflammation involves a well-coordinated and dynamic sequence of events in which several cellular adhesion molecules (CAMs) and chemotactic cytokines play an active role. The aim of the present study was to elucidate receptor-mediated interaction in mesenteric venules of leukocyte rolling/adhesion and plasma leakage. We applied intravital microscopic techniques, with the help of an analogous video image processing system, to measure changes in the microvascular integrity. Rat monoclonal antibodies (MoAb) to different CAMs were administered before inflammatory stimuli were applied. Topical application of different doses of either lipo-polysaccharide (LPS), fMet-Leu-Phe, zymosan, complement C5a, Tnf-alpha, interleukin-1beta (IL-1beta), IL2 or IL-6 resulted in a dose-dependent increase in LA. The injection of a MoAb (1 mg/kg), 15 min prior to the LPS challenge, resulted in (1) total inhibition of LA, when MoAb to rat L-section, LFA1-beta and VLA-4 were used, (2) a moderate effect with LFA-1beta and Mac-1 MoAb, and (3) only a weak influence on LA by the MoAb to rat ICAM-1 (1 mg/kg). No effects were seen with IgG1 control MoAb. LA in acute models of inflammation can be regarded as a consequence of time-dependent differential effects of CAMs, as observed through the application of different MoAb.

The role of vagus nerve on histamine- and acetylcholine-induced bronchoconstriction (experiments on cats).

During administration of highly concentrated acetyclcholine and histamine aerosol (20-40 min), different effects on tidal volume, respiratory rate, and bronchial tone could be demonstrated. Inhalation after vagotomy neither showed changes in respiratory rate nor in tidal volume. These results point out the importance of the nervus vagus in case of bronchoconstriction caused by mediators. It is discussed to which degree vagus activity is required for the direct effect of different mediators in living animals.