This work develops and validates an electrochemical approach for uric acid (UA) determinations in both endogenous (cell lysate) and physiological (serum) samples. This approach is based on the electrocatalytic reduction of enzymatically generated H(2)O(2) at the biosensor of uricase-thionine-single-walled carbon nanotube/glassy carbon (UOx-Th-SWNTs/GC) with the use of Th-SWNTs nanostructure as a mediator and an enzyme immobilization matrix. The biosensor, which was fabricated by immobilizing UOx on the surface of Th-SWNTs, exhibited a rapid response (ca. 2 s), a low detection limit (0.5 +/- 0.05 microM), a wide linear range (2 microM to 2 mM), high sensitivity (approximately 90 microA mM(-1) cm(-2)), as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, 3,4-dihydroxyphenylacetic acid, 4-acetamidophenol, etc., did not cause any interference due to the use of a low operating potential (-400 mV vs saturated calomel electrode). Therefore, this work has demonstrated a simple and effective sensing platform for selective detection of UA in the physiological levels. In particular, the developed approach could be very important and useful to determine the relative role of endogenous and physiological UA in various conditions such as hypertension and cardiovascular disease.
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http://dx.doi.org/10.1021/ac9028246 | DOI Listing |
Am J Physiol Endocrinol Metab
January 2025
The August Krogh Section for Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
Erythropoietin (EPO) is pivotal in regulating red blood cell (erythrocyte) concentrations and is primarily synthesized in the kidney. Recent research has unveiled a possible link between elevated circulating concentrations of ketone bodies (KB) and circulating EPO concentrations, however, it is not known whether nutritionally induced endogenous ketogenesis can be a stimulus to induce EPO in humans. Therefore, this study aimed to assess whether acute and chronic intake of medium-chain fatty acid (MCFA)-containing triacylglycerol (MCT), which rapidly enhances endogenous circulating KB, would elevate circulating EPO concentrations in humans, as indicated by prior work with exogenous KB administration.
View Article and Find Full Text PDFCells
January 2025
Research Institute of Medical and Health Sciences, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates.
The Kynurenine pathway is crucial in metabolizing dietary tryptophan into bioactive compounds known as kynurenines, which have been linked to glucose homeostasis. The aryl hydrocarbon receptor (AhR) has recently emerged as the endogenous receptor for the kynurenine metabolite, kynurenic acid (KYNA). However, the specific role of AhR in pancreatic β-cells remains largely unexplored.
View Article and Find Full Text PDFeNeuro
January 2025
Cognitive Psychology Unit, Faculty of Social Sciences, Leiden University, Wassenaarseweg 52 2333 AK, Leiden, Netherlands.
The brain attends to environmental rhythms by aligning the phase of internal oscillations. However, the factors underlying fluctuations in the strength of this phase entrainment remain largely unknown. In the present study we examined whether the strength of low-frequency EEG phase entrainment to rhythmic stimulus sequences varied with pupil size and posterior alpha-band power, thought to reflect arousal level and excitability of posterior cortical brain areas, respectively.
View Article and Find Full Text PDFPlant Physiol Biochem
January 2025
School of Engineering, Anhui Agricultural University, Hefei, 230036, China. Electronic address:
In this research, we sought to investigate how high temperature, salinity, and CO affect endogenous phytohormones, photosynthesis, and redox homeostasis in Caragana korshinskii Kom (C. korshinskii) leaves, as well as to comprehensively evaluate the plant's physiological response to multiple environmental stressors. The elevated temperature (e[T]), elevated Na (e[Na]), and elevated temperature and Na (e[T-Na]) treatments increased abscisic acid (ABA) and reduced zeatin-riboside (ZR), indole-3-acetic acid (IAA), and gibberellic acid (GA).
View Article and Find Full Text PDFFront Pharmacol
December 2024
School of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, China.
Introduction: The aim of this study is to examine the physiological effects of emodin on intestinal microorganisms and the liver in the BALb/c mice.
Method And Results: Following an 8-week administration of emodin at doses of 25, 50, and 100 mg/kg/day,pathological analyses revealed that emodin significantly reduced the colon length, induced colonic crypt inflammation,diminished the colonic mucus layer,and decreased the fluorescence intensity of colonic tight junction proteins ZO-1 and Occludin. Concurrently, 16S rDNA gene sequencing corroborated that emodin altered the diversity and composition of the intestinal microbiota by increasing the to ratio.
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