Determination of NADH in Frozen Rat Brain Sections by Laser-Induced Fluorescence

2001 ◽  
Vol 382 (12) ◽  
pp. 1727-1732 ◽  
Author(s):  
André Rex ◽  
Lutz Pfeifer ◽  
Heidrun Fink
Keyword(s):  
Rat Brain ◽  
Metabolic Activity ◽  
Nicotinamide Adenine Dinucleotide ◽  
Brain Structures ◽  
Laser Induced Fluorescence ◽  
Fluorescence Detector ◽  
Nadh Fluorescence ◽  
Neurotoxic Lesions ◽  
Analytical Tools

Abstract Methods to assess metabolism are important analytical tools in neuroscience. The fluorophore nicotinamide adenine dinucleotide (NADH) is a parameter of cellular metabolism. NADH fluorescence was measured using a laserbased fluorescence detector with spectral and temporal filters. Distribution and intensity of NADH fluorescence were investigated in frozen brain sections. In sections containing hippocampus the intensity of NADH fluorescence was correlated to brain structures. In order to investigate the consequences of neurotoxic lesions, 5,7-dihydroxytryptamine was injected into the dorsal raphe nucleus 4 to 240 days prior to the measurement. NADH fluorescence decreased in the affected region by 50%, indicating that no recovery in metabolic activity had occurred.

Determination of metolcarb in food by capillary electrophoresis immunoassay with a laser-induced fluorescence detector

2012 ◽  
Vol 33 (9-10) ◽  
pp. 1471-1476 ◽  
Author(s):  
Cuicui Liu ◽  
Guozhen Fang ◽  
Qiliang Deng ◽  
Yan Zhang ◽  
Jingjing Feng ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Laser Induced Fluorescence ◽  
Fluorescence Detector

ANALYTICAL TOOLS AND MANAGEMENT METHOD OF CASH FLOWS AT THE ENTERPRISE

2017 ◽  
pp. 93-105
Author(s):  
Olha NIPIALIDI
Keyword(s):  
Financial Stability ◽  
Cash Flows ◽  
Sustainable Growth ◽  
Financial Health ◽  
Traditional Assessment ◽  
Financial Condition ◽  
Efficient Management ◽  
Expert Assessments ◽  
Analytical Tools

Introduction. The most important factors for “financial health” of the company are effectively structured cash flows, precondition for sustainable growth and achievement of high end results of economic activity as a whole. Knowledge and practical use of modern methods of organization and efficient management of cash flows enables transition of the company to a new quality of economic development. Purpose. The aim of the article is the research and development of theoretical, methodological and practical recommendations concerning the organization of the management process of cash flows at the enterprise. Results. Methodology of traditional assessment of financial stability of the enterprise, its elements and the factors influencing it can significantly complement and improve through the use of advanced mathematical models that allow to analyze the accuracy and objectivity of expert assessments for determination the level of the financial condition of the enterprise. Conclusion. The system of indicators used in the analysis of cash flows at the enterprises is investigated and systematized. It is advisable to choose those indicators from the total aggregate of indicators that are the most attracted to specific users of accounting information. Methods for analyzing cash flow is supplemented as regards the determination of the integral index of financial stability, which makes it possible to install ranked of the investigated enterprise. Proposals for amendments the methodological approaches to estimating of future cash flows will allow more effectively increase usefulness and reliability of accounting and analytical information for making management decisions.

Determination of Caffeine and its Metabolites in Saliva and Urine as a Measure of CYP1A2 Metabolic Activity

2016 ◽  
Vol 12 (4) ◽  
pp. 325-332 ◽  
Author(s):  
Miroslav Turjap ◽  
Ondrej Zendulka ◽  
Zdenek Glatz ◽  
Stanislav Brejcha ◽  
Ales Madr ◽  
...  
Keyword(s):  
Metabolic Activity

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

2020 ◽  
Vol 16 (4) ◽  
pp. 428-435
Author(s):  
Ahmed F.A. Youssef ◽  
Yousry M. Issa ◽  
Kareem M. Nabil
Keyword(s):  
Hepatitis C ◽  
Human Plasma ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Protein Precipitation ◽  
Assay Method ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Relative Standard

Background: Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe. Objective: The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma. Methods: Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard. Results: Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals. Conclusion: This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

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