Glutathione Peroxidase Activity Assay with Colorimetric Method and Microplate Reading Format and Comparison with Chemiluminescence Method

Glutathione peroxidase (GPX) has a key role in the protection of organisms from oxidative damage. Many diseases and disorders are associated with changes in GPX activity. Therefore, its activity assay can be crucial in prevention, diagnosis and treatment of them. Several companies produce GPX activity assay kit but it is being imported to Iran which is expensive and time-consuming. This research has been done to investigate a simple, rapid and inexpensive method for GPX activity assay. In this study, GPX reduced cumene hydroperoxide while oxidized glutathione (GSH) to GSSG. The generated GSSG was reduced to GSH with consumption of NADPH by glutathione reductase. The decrease of NADPH absorption which was proportional to GPX activity measured at 340 nm with microplate reading format. Sensitivity, precision and accuracy have been examined. The results obtained by the colorimetric method compared with chemiluminescence method and correlation coefficient has been determined. Sensitivity of this method was 15 mU/ml. The coefficient of variation percent for intra and inter assay was less than 9.7 %. According to parallelism and recovery tests, ratio % and recovery %  ranged from 91% to 112% and correlation coefficient between the two methods was 0.9898 (n=60). Data from this study showed that the method has an acceptable sensitivity, precision and accuracy and can be suitable for both clinical and research studies. Indeed, this study is the first step of domestic commercial kit production purpose

Circulation patterns in open, wide and deep lacustrine embayments with different aspect ratios

Numerical simulations were carried out to examine the effect of different horizontal aspect ratios on wind-induced circulation within open, wide and deep lacustrine embayments. Two adjacent embayments in Lake Geneva, Switzerland, located between Morges and Lausanne on the north shore of the lake, were compared. These embayments were selected because of their similar exposure with respect to wind forcing. However, their aspect ratios are different, making them ideal case studies to evaluate the impact of the aspect ratio on the resulting circulation pattern. A previously validated 3D hydrodynamic model (Delft3D-FLOW) was employed to simulate currents in the lake for the year 2010. Detailed over-lake maps of wind, temperature and humidity were used as input to drive the model. The embayments were compared in terms of circulation patterns and conditions leading to gyre formation. Furthermore, we carried out a systematic comparison, focusing on the embayment aspect ratio by constructing different “synthetic” embayments with aspect ratios in the range 1 - 4. Subsequently, the flow field within these embayments was computed for typical meteorological regimes (dominant wind regimes and seasonality). In particular, the generation of gyres was compared for different cases. The results revealed that, even for large aspect ratios (~ 3), wind-induced circulation can still occur in open, wide, and deep lacustrine embayments. The results showed that, as expected, gyres are formed less frequently as the embayment aspect ratio increases. For this reason, gyres are much more probable in the Morges embayment than in Vidy Bay

Synthesis of a new heterocyclic dye compound as an indicator in acid and base reactions

In the present research, the use of 2-(3-hydroxyamino-2,3-dihydroimidazo[1,2-a]pyridine-2-ylidene)-2-(2-tienyl)acetonitrile as a new acid and base indicator in aquatic environments has been investigated. This compound has been synthesized by the reaction of 3-nitroimidazo [1,2-a] pyridine and 2-(2-thienyl) acetonitrile in a methanol solution by the hydrogen nucleophilic substitution. The aqueous-ethanol solution of this compound shows a change in color by adding acid and an base. For the potential function of this reagent as an indicator, the spectral properties of UV-Vis and the equilibrium of acid and base source have been examined. The results show that the reagent is an amphoteric with two stable ionization factors Ka and Kb with poor acid and base properties. Indicator dissociation constants in aqueous solutions specified by spectrophotometric method are pKa = 9.73 and pKb = 11.57. The types of base that can be titrated with this index have been reported. This index has been compared with effective acid and base indexes with similar pH range.

Synthesis of a new heterocyclic dye compound as an indicator in acid and base reactions

287-290In the present research, the use of 2-(3-hydroxyamino-2,3-dihydroimidazo[1,2-a]pyridine-2-ylidene)-2-(2-tienyl)acetonitrile as a new acid and base indicator in aquatic environments has been investigated. This compound has been synthesized by the reaction of 3-nitroimidazo [1,2-a] pyridine and 2-(2-thienyl) acetonitrile in a methanol solution by the hydrogen nucleophilic substitution. The aqueous-ethanol solution of this compound shows a change in color by adding acid and an base. For the potential function of this reagent as an indicator, the spectral properties of UV-Vis and the equilibrium of acid and base source have been examined. The results show that the reagent is an amphoteric with two stable ionization factors Ka and Kb with poor acid and base properties. Indicator dissociation constants in aqueous solutions specified by spectrophotometric method are pKa = 9.73 and pKb = 11.57. The types of base that can be titrated with this index have been reported. This index has been compared with effective acid and base indexes with similar pH range

Total Antioxidant Capacity Determination with Colorimetric Method and Microplate Reading Format and Comparison with Chemilumin Essence Assay

Total antioxidant capacity (TAC) is related to a variety of molecules that protect biological systems against reactive oxygen species (ROS). The importance of total antioxidants results in the requirement of TAC assay methods. This study is done to design a simple, rapid and inexpensive method for TAC measurement. In this method, ABTS (2, 2′-azino-bis [3-ethylbenzthiazoline-6-sulfonic acid]) was incubated with met myoglobin and H2O2 to produce green radical cation ABTS+. Antioxidants were suppressed the color production, thereby reducing the intensity of the color that was proportional to the concentration of antioxidants, measured at 600nm with a microplate reading format. Trolox was served as a standard or control antioxidant. Sensitivity, precision and accuracy were examined to check the validity of the method. Sensitivity of this method was 0.10 U/ml. The coefficient of variation percent for intra and inter assay was less than 9.6%. According to parallelism and recovery tests, ratio% and recovery% ranged from 90.9-108% and correlation coefficient in comparison with the sensitive chemiluminescence method was 0.9897 (n=60). Data from this study showed that this method has a good sensitivity, precision and accuracy and can be suitable for clinical and research uses

Glutathione Peroxidase Activity Assay with Colorimetric Method and Microplate Reading Format and Comparison with Chemiluminescence Method

Glutathione peroxidase (GPX) has a key role in the protection of organisms from oxidative damage. Many diseases and disorders are associated with changes in GPX activity. Therefore, its activity assay can be crucial in prevention, diagnosis and treatment of them. Several companies produce GPX activity assay kit but it is being imported to Iran which is expensive and time-consuming. This research has been done to investigate a simple, rapid and inexpensive method for GPX activity assay. In this study, GPX reduced cumene hydroperoxide while oxidized glutathione (GSH) to GSSG. The generated GSSG was reduced to GSH with consumption of NADPH by glutathione reductase. The decrease of NADPH absorption which was proportional to GPX activity measured at 340 nm with microplate reading format. Sensitivity, precision and accuracy have been examined. The results obtained by the colorimetric method compared with chemiluminescence method and correlation coefficient has been determined. Sensitivity of this method was 15 mU/ml. The coefficient of variation percent for intra and inter assay was less than 9.7 %. According to parallelism and recovery tests, ratio % and recovery %  ranged from 91% to 112% and correlation coefficient between the two methods was 0.9898 (n=60). Data from this study showed that the method has an acceptable sensitivity, precision and accuracy and can be suitable for both clinical and research studies. Indeed, this study is the first step of domestic commercial kit production purpose

Involvement of D1 and D2 dopamine receptors in the antidepressant-like effects of selegiline in maternal separation model of mouse.

Mother-infant interactions are known to be associated with the psychological well-being of an individual in adulthood. It is well accepted that emotional stress in early life, such as maternal separation (MS), leads to alterations in the neurotransmission systems of various brain regions, especially the mesolimbic dopaminergic system, and subsequently can increase the risk for development of psychiatric disorders including depression in adulthood. Selegiline is an irreversible monoamine oxidase (MAO) type B inhibitor which increases striatal dopamine levels and exerts an antidepressant effect. In this study, 180min of MS stress was applied to mice at postnatal day (PND) 2-14 followed by behavioral tests for determining depressive-like behaviors, such as forced swimming test (FST), splash test and sucrose preference test (SPT) in adult mice (PND 50). The open field test (OFT) also was applied to validate FST results. We used SCH23390 (D1 antagonist) and sulpiride (D2 antagonist) in order to determine the role of D1 and D2 dopamine receptors in antidepressant-like effects of selegiline. Our results revealed that MS provoked depressive-like behaviors in adult male mice, and the administration of selegiline attenuated depressive-like behaviors in MS mice. Our findings showed that D1 dopamine receptors facilitate the positive effects of selegiline on the passive behavior in the FST. Furthermore, antidepressant effects of selegiline on hedonic difficulties are mediated via D2 receptor in the SPT. The results of the splash test revealed that both D1 and D2 receptors mediate the protective effect of selegiline against motivational and self-care problems. Based on our results, we conclude that both D1 and D2 dopamine receptors are involved in mediating the antidepressant-like effect of selegiline. We found that D1 receptors mediate an effect on despair behavior, D2 receptors mediate an effect on anhedonia, and both D1 and D2 receptors contribute to the protective effects of selegiline on motivational complications

Gyre formation in open and deep lacustrine embayments: The example of Lake Geneva, Switzerland

Numerical simulations were carried out to investigate gyres within open lacustrine embayments subjected to parallel-to-shore currents. In such embayments, gyre formation occurs due to flow separation at the embayment’s upstream edge. High momentum fluid from the mixing layer between the embayment and offshore flows into the embayment and produces recirculating flow. Systematic numerical experiments using different synthetic embayment configurations were used to examine the impact of embayment geometry. Geometries included embayments with different aspect ratios, depths and embayment corner angles. The magnitudes of the recirculation and turbulent kinetic energy (TKE) in the embayment vary significantly for angles in the range 40° to 55°. Embayments with corner angles less than 50° have much stronger recirculation and TKE, other parameters remaining the same. The numerical findings are consistent with gyre formation observed in two embayments located in Lake Geneva, Switzerland, and thus help explain flow patterns recorded in lacustrine shoreline regions

Biomaterials in Valvular Heart Diseases

Valvular heart disease (VHD) occurs as the result of valvular malfunction, which can greatly reduce patient\u27s quality of life and if left untreated may lead to death. Different treatment regiments are available for management of this defect, which can be helpful in reducing the symptoms. The global commitment to reduce VHD-related mortality rates has enhanced the need for new therapeutic approaches. During the past decade, development of innovative pharmacological and surgical approaches have dramatically improved the quality of life for VHD patients, yet the search for low cost, more effective, and less invasive approaches is ongoing. The gold standard approach for VHD management is to replace or repair the injured valvular tissue with natural or synthetic biomaterials. Application of these biomaterials for cardiac valve regeneration and repair holds a great promise for treatment of this type of heart disease. The focus of the present review is the current use of different types of biomaterials in treatment of valvular heart diseases