Enzymatic flow injection method for rapid determination of choline in urine with electrochemiluminescence detection

In order to determine trace choline in human urine, a flow injection analysis (FIA) system has been developed by coupling an enzyme reactor with an electrochemiluminescence (ECL) detector. The enzyme reactor is prepared by covalently immobilizing choline oxidase (ChOx) onto the aminopropyl-controlled pore glass beads, which are then carefully packed into a micro column. The enzyme reactor catalyzes the production of hydrogen peroxide that is in direct proportion to the concentration of choline. In this study, the enzymatically produced hydrogen peroxide was detected by an ECL detector positioned at the down stream of an enzyme react:or based on the luminol/H2O2 ECL system. Under the optimized condition, the enzymatic FIA/ECL provided high sensitivity for the determination of choline with the detection limit as low as 0.05 mu M (absolute detection limit was at sub pmol level). The method was successfully applied in the determination of choline in the samples of human urine, and the analytical results were in good agreement with those obtained by using the microbore HPLC with an immobilized enzyme reactor-electrochemical detection system.ArticleBioelectrochemistry. 79(1):147-151 (2010)journal articl

Characterization of electrochemiluminescence of tris(2,2′-bipyridine)ruthenium(II) with glyphosate as coreactant in aqueous solution

Glyphosate, a phosphorus-containing amino acid type herbicide was used as a coreactant for studying of electrochemiluminescence (ECL) reaction of tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy)(3)(2+)] in an aqueous solution. In a phosphate buffer solution of pH 8, glyphosate itself was known to be electrochemically inactive at glassy carbon electrode, however, it participated in a homogeneous chemical reaction with the electrogenerated Ru(bpy)(3)(3+), and resulted in producing Ru(bpy)(3)(2+) species at the electrode surface. Kinetic and mechanistic information for the catalysis of glyphosate oxidation were evaluated by the steady-state voltammetric measurement with an ultramicroelectrode. The simulated cyclic voltammogram based on this mechanism was in good agreement with that obtained experimentally. ECL reaction of Ru(bpy)(3)(2+)/glyphosate system was found to be strongly dependent on the media pH. In a pH region of 5-9, an ECL wave appeared at ca. +1.1 V vs. Ag/AgCl, which was caused by the generation of *Ru(bpy)(3)(2+) via a Ru(bpy)(3)(3+)-mediated oxidation of glyphosate. When pH >10, a second ECL wave was observed at ca. +1.35 V vs. Ag/AgCl, which was believed to be associated with a reaction between Ru(bpy)(3)(3+) and the species from direct oxidation of GLYP at a GC electrode surface.ArticleElectrochimica Acta 55(20):5532-5537 (2010)journal articl

Potential-modulated electrochemiluminescence of a tris(2,2′-bipyridine) ruthenium(II) / lidocaine system under 430 kHz ultrasound irradiation

ArticleUltrasonics Sonochemistry. 63: 104947 (2020)journal articl

Flexural behavior of slab-rib integrated bridge decks with GFRP skin and polyurethane foam core

This paper presents experimental and analytical studies on flexural behavior of slab-rib integrated Sandwich composite decks. The influences of layers of glass fiber-reinforced polymer (GFRP) facesheets, foam densities, and the existence of webs and cross beams are discussed herein. The test results showed that the existence of vertical webs remarkably improved the debonding of the facesheets from the foam core, thus increasing the ultimate load by 59% compared with the specimens without webs. However, the existence of horizontal webs has insignificant effect on the failure mode and ultimate load. Increasing the number of layers of GFRP facesheets from 2 to 4 and 6 results in 100% and 214% increments in ultimate loads, respectively, while the specimen with lower density of foam had a higher ultimate load than the specimen with higher density of foam due to deformation compatibility between GFRP skins and foam core with low density. The analysis software Abaqus Explicit was used to simulate the flexural behavior of test specimens, and the numerical results agreed well with the test data. The verified finite element model was extended to analyze the influences of the number of GFRP layers on the top of decks and the height of vertical webs. Based on equivalent method and compatibility of shear deformation, the flexural and shear rigidities were estimated. Then, analytical solution for displacement of the slab-rib integrated Sandwich composite decks subjected to four-point load was derived out. Comparison of analytical and experimental results shows that the displacements can be precisely predicted by the present theoretical model

Quantitative determination and pharmacokinetics of salvianolic acid l, a novel phenolic acid constituent from salvia miltiorrhiza, in rat plasma by high-performance liquid chromatography

A simple, rapid and selective HPLC method was developed for the determination of a novel phenolic acid constituent in rat plasma, salvianolic acid L (SAL), extracted from the dried root of Salvia miltiorrhiza (Danshen). Plasma samples were extracted by ethyl acetate after addition of the internal standard tinidazole. The appropriate separations were achieved using a C18 column with the mobile phase composed of a mixture of acetonitrile/water/formic acid (35:65:0.1, v/v/v) at the flow rate of 0.8 mL/min, and the wavelength of determination by diode-array detector (DAD) detection was 327 nm. Good linearity (r = 0.9996) was obtained within the concentration of 0.05-50 μg/mL. The intra- and inter-day assay precisions ranged from 0.60 to 5.91% and 3.52 to 7.00%, respectively. The accuracy was between 95.8 to 103.8%. In addition, the stability and extraction recovery involved in the method were also validated. This method was successfully applied to investigate the pharmacokinetic study of SAL in rats after a single intravenous administration dose of 2.0, 4.0, and 8.0 mg/kg, respectively.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Metabolic determination of decursinol using human liver microsome

Purpose: To determine new metabolites of the main components of Angelica gigas known to give anti-inflammation and pain relief Methods: Decursinol and blank sample were metabolized in human liver microsomes. The metabolized samples were centrifuged and deproteinated by adding 3 mL acetonitrile. The acetonitrile layer was concentrated and reconstituted in methanol. Finally, the prepared sample was injected into the LC-Q- TOF-MS. Results: Four new metabolites of decursinol with m/z ranging from 263.0912 ~ 263.0920 were identified as hydroxylated forms of decursinol, and the hydroxylated position of each metabolite was characterized using TOF mass spectrum. Their error values of detected m/z were 0.38 ~ 2.29 ppm, which indicates high accuracy of analysis. Conclusion: Previously unreported decursinol metabolites have been identified in this study. The findings provide athe basis for further pharmaceutical studies and functional food development using decursinol

Quantitative determination and pharmacokinetics of salvianolic acid l, a novel phenolic acid constituent from salvia miltiorrhiza, in rat plasma by high-performance liquid chromatography

A simple, rapid and selective HPLC method was developed for the determination of a novel phenolic acid constituent in rat plasma, salvianolic acid L (SAL), extracted from the dried root of Salvia miltiorrhiza (Danshen). Plasma samples were extracted by ethyl acetate after addition of the internal standard tinidazole. The appropriate separations were achieved using a C18 column with the mobile phase composed of a mixture of acetonitrile/water/formic acid (35:65:0.1, v/v/v) at the flow rate of 0.8 mL/min, and the wavelength of determination by diode-array detector (DAD) detection was 327 nm. Good linearity (r = 0.9996) was obtained within the concentration of 0.05-50 μg/mL. The intra- and inter-day assay precisions ranged from 0.60 to 5.91% and 3.52 to 7.00%, respectively. The accuracy was between 95.8 to 103.8%. In addition, the stability and extraction recovery involved in the method were also validated. This method was successfully applied to investigate the pharmacokinetic study of SAL in rats after a single intravenous administration dose of 2.0, 4.0, and 8.0 mg/kg, respectively.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Fasciotomy in compartment syndrome from snakebite

Background Local symptoms and signs of snake envenomation mimic the clinical features of compartment syndrome. It is important to measure the intracompartmental pressure to diagnose compartment syndrome. In this study, we present our experiences of confirming compartment syndrome and performing fasciotomy in snakebite patients based on high intracompartmental pressure findings. Methods The medical records of patients who visited the trauma center of Wonju Severance Christian Hospital from January 2010 to December 2015 for the management of venomous snakebite were retrospectively reviewed. Starting in 2014, fasciotomy was performed in patients with an intracompartmental pressure of more than 40 mmHg in addition to the clinical symptoms of compartment syndrome. Results A total of 158 patients with snakebite came to the hospital within 48 hours for treatment. Most patients (110 patients) were bitten at the upper extremities (69.6%). Since 2014, 33 out of 59 patients were suspected to have compartment syndrome, and their intracompartmental pressures were measured. Seventeen of those patients had a high intracompartmental pressure (average, 49.6 mmHg; range, 37–88 mmHg), and fasciotomy was performed. Conclusions In this study, as many as 10.8% of all cases were in need of fasciotomy when compartment syndrome was diagnosed by measuring the intracompartmental pressure. Previously, it was reported that fasciotomy was not required in many cases of compartment syndrome originating from snakebite. However, some patients may develop very severe compartment syndrome, requiring fasciotomy

Phloretin Prevents Diabetic Cardiomyopathy by Dissociating Keap1/Nrf2 Complex and Inhibiting Oxidative Stress

Hyperglycemia induces chronic inflammation and oxidative stress in cardiomyocyte, which are the main pathological changes of diabetic cardiomyopathy (DCM). Treatment aimed at these processes may be beneficial in DCM. Phloretin (PHL), a promising natural product, has many pharmacological activities, such as anti-inflammatory, anticancer, and anti-oxidative function. The aim of this study was to investigate whether PHL could ameliorate the high glucose-mediated oxidation, hypertrophy, and fibrosis in H9c2 cells and attenuate the inflammation- and oxidation-mediated cardiac injury. In this study, PHL induced significantly inhibitory effect on the expression of pro-inflammatory, hypertrophy, pro-oxidant, and fibrosis cytokines in high glucose-stimulated cardiac H9c2 cells. Furthermore, PHL decreased the levels of serum lactate dehydrogenase, aspartate aminotransferase, and creatine kinase-MB, and attenuated the progress in the fibrosis, oxidative stress, and pathological parameters via Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor E2-related factor 2 (Nrf2) pathway in diabetic mice. In additional, molecular modeling and immunoblotting results confirmed that PHL might obstruct the interaction between Nrf2 and Keap1 through direct binding Keap1, and promoting Nrf2 expression. These results provided evidence that PHL could suppress high glucose-induced cardiomyocyte oxidation and fibrosis injury, and that targeting Keap1/Nrf2 may provide a novel therapeutic strategy for human DCM in the future

Epidemiologic study of hand and upper extremity injuries by power tools

Background Hand injuries caused by chain saws, electric saws, and hand grinders range from simple lacerations to tendon injuries, fractures, and even amputations. This study aimed to understand the distribution of various types of hand and upper extremity injuries caused by power tools, in order to help prevent them, by investigating the incidence and cause of power tool injuries treated over a 4-year period at a single institution in Korea. Methods We reviewed the medical records of patients who visited a single institution for power tool-induced injuries from 2011 to 2014. The distribution of sex, age, injured body part, type of injury, and mechanism of injury sustained by patients who received hand and upper extremity injuries from using an engine saw, electric saw, or hand grinder was evaluated. Results Among 594 subjects who were injured by power tools, 261 cases were hand and upper extremity injuries. The average age was 53.2 years. Tendon injury was the most common type of injury. An electric saw was the most common type of power tool used. More injuries occurred in non-occupational settings than in occupational settings. Conclusions In this study, power tool-induced hand and upper extremity injuries were mostly caused by direct contact with electric saw blades. More injuries occurred due to non-occupational use of these tools, but the ratios of amputations and structural injuries were similar in the non-occupational and occupational groups