Search

The current review paper portrays the important link of different nutrients like trace elements, proteins, fatty acids, vitamins, and amino acids with the immune system as well as information related to metabolic paradoxes. Optimum working of the metabolic system is essential because it gives various types of supplements to the human body and aid in chemical pathways. Here related data have been retrieved from two databases i.e., PubMed and Google scholar to grasp detailed knowledge about micronutrients and nutrients as well as their association in the metabolic system. Like protein play important role in the normal development of different immune components, amino acids including alanine, Arginine, and glutamic acid properly control the movement of neutrophils, macrophages, and cytokines. While fatty acids act as an anti-inflammatory agent because they possess the ability to inhibit the expression of the MHC class. Apart from these, many essential molecules like uric acid, proteins, calcium, lanolin are also obtained as end products after catabolic and anabolic reactions, and it was found that the uric acid paradox has a cancer inhibitory role. Additionally, TGF and IL-6 paradoxes have a role in the development of tumors, the onset of diabetes, and low-grade inflammatory disorders respectively. However, the entire functioning of metabolic processes depends upon daily diet because humans get the important nutrient from the diet which further vital role in the immune system. Moreover, it was also observed that calcium paradox is related to heart disorders because high calcium accumulation leads to cardiac disorders. Thus, the complete knowledge about these essential components as well as metabolic paradoxes is very important due to their antagonistic role to plan better and improved therapeutic strategies for various diseases.

Introduction: Results from recent trials assessing the effect of oral vitamin C supplementation on serum uric acid (SUA) have been inconsistent., Objectives: The purpose of this study was to explore the association between oral vitamin C supplementation and serum uric acid., Methods: PUBMED, EMBASE, CNKI, Web of Science, and CENTRAL of Cochrane library databases were searched to identify relevant articles published up to February 2020. Heterogeneity was evaluated using I-square (I 2 ) statistics. Random-effects model was used to pool weighted mean differences (WMD) and 95 % confidence interval (CI) as summary effect sizes., Results: The total sixteen eligible randomized controlled trials (RCTs) containing 1,013 participants were included in this meta-analysis. The pooled findings showed that vitamin C supplementation had a significant effect of lowering SUA. The subgroup analyses showed that the effect of vitamin C supplementation on SUA has positive association with mean age of participants <65 years old, the use of placebo or blank control, duration of trials <1 month and high-quality studies. In addition, sensitivity analysis showed that the results of this study were stable. Both Egger's test and Begg's test demonstrated that no evidence of significant publication bias., Conclusions: The results of present meta-analysis have demonstrated that vitamin C supplementation could make a reduction of SUA. The use of placebo, duration of intervention, age of the subjects and study quality have an impact on the effect of oral vitamin C, but the baseline of SUA not., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Estradiol (E2) is a hormone that influences various aspects of women's health. Beyond its reproductive functions, E2 impacts neurotransmitter systems such as dopamine (DA). Vertically aligned carbon nanofibers (VACNFs) have shown good sensitivity, selectivity against ascorbic acid (AA) and uric acid (UA), biocompatibility, and reduced fouling in DA sensing. In this study, we explore the use of Ti-Ni-CNF electrodes with CNFs grown for 5 min and 30 min for the direct electrochemical co-detection of E2 and DA. The longer growth time led to a 142% increase in average CNF length and a 36% larger electroactive surface area. In E2 detection, the electrodes demonstrate a wide linear range of 0.05–10 µM and sensitivity of 0.016 and 0.020 µA/µM for Ti-Ni-CNF-5 min and Ti-Ni-CNF-30 min, respectively. The sensor performance remains largely unaffected even in the presence of other steroid hormones such as progesterone and testosterone. Co-detection of equimolar E2 and DA shows promising peak separation of 0.34 ± 0.01 V and repeatability after 10 measurements. A notable improvement in the E2/DA peak current ratio, from 0.53 ± 0.07 to 0.81 ± 0.16, was achieved with the increased CNF length. Our results demonstrate the influence of adsorption sites in electrochemical detection, especially for analytes such as E2 and DA that both rely on adsorption for oxidation. While detecting small and fluctuating physiological concentrations remains a challenge, these findings can be used in choosing and fabricating electrode materials for more accurate and accessible continuous hormone measurements, including the possibility of multianalyte sensing platforms. [ABSTRACT FROM AUTHOR]

We present a sensor array of microscale organic electrochemical transistors (OECTs) using poly (3,4−ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) as the channel material. The devices show high sensitivity and selectivity to detect dopamine (DA) with platinum (Pt) as a pseudo−reference gate electrode. First, we describe the wafer−scale fabrication process for manufacturing the PEDOT:PSS OECTs, and then we introduce a dilution method to adjust the thickness of the PEDOT:PSS film. Next, we investigate the effect of the film thickness on the sensitivity of DA detection. Reducing the film thickness enhances the sensitivity of DA detection within the concentration range of 1 μM to 100 μM. The OECTs show impressive sensitivitywith a limit of detection (LoD) as low as 1 nM and a high selectivity against uric acid (UA) and ascorbic acid (AA). Finally, we modify the surface of the Pt gate electrode with chitosan to improve the selectivity of OECTs at high concentrations of up to 100 µM to expand the detection range. [ABSTRACT FROM AUTHOR]

Composite sensor-based carbon paste electrode (CPE) was modified with gold nanoparticles and polymelamine (AuNPs/PM/CPE) via electropolymerization and electrodeposition. The AuNPs/PM/CPE was used to investigate simultaneous dopamine, ascorbic acid, and uric acid. The surface morphology of AuNPs/PM/CPE was observed using scanning electron microscopy (SEM). The electrochemical behavior was investigated using the cyclic voltammetry (CV) technique. The AuNPs/PM/CPE shows higher electrochemical activities and has a large effective surface area compared with CPE, PM/CPE, and AuNPs/CPE. Under the optimum conditions for simultaneous analysis, the AuNPs/PM/CPE exhibit a linear voltammetric response and detection of limits of calculated 0.817 µM, 0.246 µM, and 1.233 µM for dopamine, ascorbic acid, and uric acid. The AuNPs/PM/CPE presented selective sensors in the simultaneous of dopamine, ascorbic acid, and uric acid. The modified electrode was successfully applied and analyzed in the real sample of human urine and obtained satisfactory recovery. [ABSTRACT FROM AUTHOR]

Dopamine (DA), ascorbic acid (AA), and uric acid (UA) are crucial neurochemicals, and their abnormal levels are involved in various neurological disorders. While electrodes for their detection have been developed, achieving the sensitivity required for in vivo applications remains a challenge. In this study, we proposed a synthetic Au24Cd nanoenzyme (ACNE) that significantly enhanced the electrochemical performance of metal electrodes. ACNE-modified electrodes demonstrated a remarkable 10-fold reduction in impedance compared to silver microelectrodes. Furthermore, we validated their excellent electrocatalytic activity and sensitivity using five electrochemical detection methods, including cyclic voltammetry, differential pulse voltammetry, square-wave pulse voltammetry, normal pulse voltammetry, and linear scanning voltammetry. Importantly, the stability of gold microelectrodes (Au MEs) modified with ACNEs was significantly improved, exhibiting a 30-fold enhancement compared to Au MEs. This improved performance suggests that ACNE functionalization holds great promise for developing micro-biosensors with enhanced sensitivity and stability for detecting small molecules. [ABSTRACT FROM AUTHOR]

Two-dimensional MXenes have become an important material for electrochemical sensing of biomolecules due to their excellent electric properties, large surface area and hydrophilicity. However, the simultaneous detection of multiple biomolecules using MXene-based electrodes is still a challenge. Here, a simple solvothermal process was used to synthesis the Ti3C2Tx coated with TiO2 nanosheets (Ti3C2Tx@TiO2 NSs). The surface modification of TiO2 NSs on Ti3C2Tx can effectively reduce the self-accumulation of Ti3C2Tx and improve stability. Glassy carbon electrode was modified by Ti3C2Tx@TiO2 NSs (Ti3C2Tx@TiO2 NSs/GCE) and was able simultaneously to detect dopamine (DA), ascorbic acid (AA) and uric acid (UA). Under concentrations ranging from 200 to 1000 μM, 40 to 300 μM and 50 to 400 μM, the limit of detection (LOD) is 2.91 μM, 0.19 μM and 0.25 μM for AA, DA and UA, respectively. Furthermore, Ti3C2Tx@TiO2 NSs/GCE demonstrated remarkable stability and reliable reproducibility for the detection of AA/DA/UA. [ABSTRACT FROM AUTHOR]

Antioxidant-related parameters and anti-inflammatory and antimicrobial activities against Listeria monocytogenes were assessed in eight North East Spain poplar propolis samples. Propolis extracts (PEs) were obtained using 70% ethanol (PEE) and methanol (PME). Yield and total phenol compounds were higher in PEE. Phenolic acids were analyzed by a high-performance liquid chromatograph–diode array detector. Caffeic and ferulic acids were quantified in all PEE and PME. All samples contained p-coumaric acid (quantified in 6 PEE and in 3 PME). Ascorbic acid was detected in all propolis, but mainly quantified in PME (≤0.37 mg/g PE). Biological properties were tested on PEE. As for antiradical activities, trolox equivalent antioxidant capacity (TEAC) [against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)•+], ranged between 578 and 4620 µmol trolox/g, 2,2-diphenyl-1-picrylhydrazyl (DPPH) (against DPPH free radical), between 0.049 and 0.094 mg/mL, antioxidant activity against hydroxyl (•OH) radical (AOA), between 0.04 and 11.01 mmol uric acid/g, and oxygen radical absorbance capacity (ORAC) against peroxyl (ROO•) radical between 122 and 3282 µmol trolox/g. Results of TEAC, AOA, and ORAC were significantly correlated. IC50 anti-inflammatory activity ranged from 1.08 to 6.19 mg/mL. Propolis showed higher inhibitory activity against L. monocytogenes CECT934 and L. monocytogenes CP101 by agar well diffusion (P <.05) (10.5 and 10.2 mm, respectively) than against L. monocytogenes CP102 (7.0 mm). Data of this research show that North East Spain propolis may be of interest for pharmaceutical and food industry use. [ABSTRACT FROM AUTHOR]

In this study, we designed a novel electrochemical sensor by modifying a glass carbon electrode (GCE) with Pd confined mesoporous carbon hollow nanospheres (Pd/MCHS) for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The structure and morphological characteristics of the Pd/MCHS nanocomposite and the Pd/MCHS/GCE sensor are comprehensively examined using SEM, TEM, XRD and EDX. The electrochemical properties of the prepared sensor are investigated through CV and DPV, which reveal three resolved oxidation peaks for AA, DA, and UA, thereby verifying the simultaneous detection of the three analytes. Benefiting from its tailorable properties, the Pd/MCHS nanocomposite provides a large surface area, rapid electron transfer ability, good catalytic activity, and high conductivity with good electrochemical behavior for the determination of AA, DA, and UA. Under optimized conditions, the Pd/MCHS/GCE sensor exhibited a linear response in the concentration ranges of 300–9000, 2–50, and 20–500 µM for AA, DA, and UA, respectively. The corresponding limit of detection (LOD) values were determined to be 51.03, 0.14, and 4.96 µM, respectively. Moreover, the Pd/MCHS/GCE sensor demonstrated outstanding selectivity, reproducibility, and stability. The recovery percentages of AA, DA, and UA in real samples, including a vitamin C tablet, DA injection, and human urine, range from 99.8–110.9%, 99.04–100.45%, and 98.80–100.49%, respectively. Overall, the proposed sensor can serve as a useful reference for the construction of a high-performance electrochemical sensing platform. [ABSTRACT FROM AUTHOR]

Biosensors function as sophisticated devices, converting biochemical reactions into electrical signals. Contemporary emphasis on developing biosensor devices with refined sensitivity and selectivity is critical due to their extensive functional capabilities. However, a significant challenge lies in the binding affinity of biosensors to biomolecules, requiring adept conversion and amplification of interactions into various signal modalities like electrical, optical, gravimetric, and electrochemical outputs. Overcoming challenges associated with sensitivity, detection limits, response time, reproducibility, and stability is essential for efficient biosensor creation. The central aspect of the fabrication of any biosensor is focused towards forming an effective interface between the analyte electrode which significantly influences the overall biosensor quality. Polymers and macromolecular systems are favored for their distinct properties and versatile applications. Enhancing the properties and conductivity of these systems can be achieved through incorporating nanoparticles or carbonaceous moieties. Hybrid composite materials, possessing a unique combination of attributes like advanced sensitivity, selectivity, thermal stability, mechanical flexibility, biocompatibility, and tunable electrical properties, emerge as promising candidates for biosensor applications. In addition, this approach enhances the electrochemical response, signal amplification, and stability of fabricated biosensors, contributing to their effectiveness. This review predominantly explores recent advancements in utilizing macrocyclic and macromolecular conjugated systems, such as phthalocyanines, porphyrins, polymers, etc. and their hybrids, with a specific focus on signal amplification in biosensors. It comprehensively covers synthetic strategies, properties, working mechanisms, and the potential of these systems for detecting biomolecules like glucose, hydrogen peroxide, uric acid, ascorbic acid, dopamine, cholesterol, amino acids, and cancer cells. Furthermore, this review delves into the progress made, elucidating the mechanisms responsible for signal amplification. The Conclusion addresses the challenges and future directions of macromolecule-based hybrids in biosensor applications, providing a concise overview of this evolving field. The narrative emphasizes the importance of biosensor technology advancement, illustrating the role of smart design and material enhancement in improving performance across various domains. [ABSTRACT FROM AUTHOR]

In this study, a novel electrodeposition of poly(2,4,6‐trihydroxybenzaldehyde) on bare glassy carbon electrode for dopamine detection was reported. 2,4,6‐trihydroxybenzaldehyde and the electrodeposited poly(2,4,6‐trihydroxybenzaldehyde) were characterized using Fourier transform‐infrared spectroscopy, UV‐visible spectroscopy, and scanning electron microscopy. The bare electrode modified with the optimum amount of 2,4,6‐trihydroxybenzaldehyde (PTGCE) was used for dopamine electroanalysis. The linear dynamic range and the limit of detection of DA at PTGCE were 0.70‐19.48 μM and 19.48–53.30 μM, and 0.64 μM, respectively. The modified electrode showed outstanding discriminatory dopamine detection in the presence of uric acid and ascorbic acid due to a dopamine‐uric acid and a dopamine‐ascorbic acid peak‐to‐peak separation of 160 mV and 200 mV, respectively. The proposed sensor showed considerable reproducibility of dopamine current response and excellent % dopamine recovery of 99.70 % from the real sample solution. [ABSTRACT FROM AUTHOR]

To date, little is known concerning the circulating levels of biochemically relevant metabolites (antioxidants, oxidative/nitrosative stress biomarkers, purines, and pyrimidines) in patients with primary myelofibrosis (PMF), a rare form of myeloproliferative tumor causing a dramatic decrease in erythropoiesis and angiogenesis. In this study, using a targeted metabolomic approach, serum samples of 22 PMF patients and of 22 control healthy donors were analyzed to quantify the circulating concentrations of hypoxanthine, xanthine, uric acid (as representative purines), uracil, β-pseudouridine, uridine (as representative pyrimidines), reduced glutathione (GSH), ascorbic acid (as two of the main water-soluble antioxidants), malondialdehyde, nitrite, nitrate (as oxidative/nitrosative stress biomarkers) and creatinine, using well-established HPLC method for their determination. Results showed that PMF patients have dramatic depletions of both ascorbic acid and GSH (37.3- and 3.81-times lower circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001), accompanied by significant increases in malondialdehyde (MDA) and nitrite + nitrate (4.73- and 1.66-times higher circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001). Additionally, PMF patients have remarkable alterations of circulating purines, pyrimidines, and creatinine, suggesting potential mitochondrial dysfunctions causing energy metabolism imbalance and consequent increases in these cell energy-related compounds. Overall, these results, besides evidencing previously unknown serum metabolic alterations in PMF patients, suggest that the determination of serum levels of the aforementioned compounds may be useful to evaluate PMF patients on hospital admission for adjunctive therapies aimed at recovering their correct antioxidant status, as well as to monitor patients' status and potential pharmacological treatments. [ABSTRACT FROM AUTHOR]

In this work, an electrochemical method for sensitive determination of creatinine has been reported based on its reaction with 2-nitrobenzaldehyde and using differential pulse voltammetry technique. A plausible mechanism of the reaction has been proposed and successful application of this method for creatinine detection in a real sample (human urine) has also been demonstrated. The mechanism is indicative of the formation of multiple electroactive species in the process. The linear range of detection being 1–25 mM, with LOD of 0.50 mM and an excellent R2 value of 0.99, was suitable enough for the detection of creatinine in human urine. Interference studies of urea, uric acid, glucose, ascorbic acid and dopamine were done and found to be within the acceptable limit. All the components except uric acid showed an interference of less than 3.2%, while uric acid showed maximum interference of 8.4%. Its robustness, high selectivity, good sensitivity, and low detection limit have projected it as a promising new tool for a point-of-care testing device. [ABSTRACT FROM AUTHOR]

Present study was conducted in Department of Biochemistry Dr. SCGMC Nanded over the period of 18 months. Well informed written consent was taken from every study subject and it was ethically cleared from the institutional ethical committee. The study population consisted of 120 pregnant women, of whom 60 were normal pregnant healthy women taken as control and 60 pregnant women with diagnosis of Preeclampsia were taken as cases. The cases were divided in two groups as mild and severe cases of preeclampsia. Measurement of inflammatory marker like C-reactive protein, measurement of lipid peroxidation markers like serum malondialdehyde. And for oxidative stress serum superoxide dismutase, serum uric acid and Vitamin C were measured among the study subject. Serum CRP was found to be significantly increased with the severity of preeclampsia in mild and severe cases when compared with normal pregnant women. High levels of CRP in preeclampsia highlight the underlying pathogenesis of endothelial inflammation and disease progression. Serum MDA levels was also found to be significantly increased with the severity of preeclampsia in mild and severe cases when compared to controls. This rise was because of the increased oxidative stress in preeclampsia resulting in higher lipid peroxidation. Also, antioxidants like serum SOD and Vit C were decreased with the severity of preeclampsia as compared to controls indicating their increased turnover for the prevention of oxidative damage and lipid per-oxidation. In contrast serum uric acid was shown to be increased with the severity of pre-eclampsia in mild and severe cases when compared to controls. Increase in the levels of serum uric acid was mainly because of decreased urate excretion commonly found in preeclamptic women. [ABSTRACT FROM AUTHOR]

Background: We performed this systematic review and meta-analysis to synthesize all studies that reported the level of oxidative and antioxidative markers in recurrent aphthous stomatitis (RAS) patients compared to controls. Methods: We registered our study in PROSPERO (CRD42023431310). PubMed, ProQuest, Scopus, EMBASE, Google Scholar, and Web of Science were searched to find relevant publications up to June 5, 2023. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. We included 30 articles after multiple stags of screening. Results: We found that erythrocyte superoxide dismutase and Glutathione peroxidase activity were significantly lower in patients with RAS compared to healthy controls (SMD = − 1.00, 95%CI = -1.79 to -0.21, p = 0.013, and SMD = − 1.90, 95%CI = -3.43 to -0.38, p = 0.01, Respectively). However, there was not any difference between patients with RAS and healthy controls in erythrocyte Catalase (SMD = − 0.71, 95%CI = -1.56–0.14, p = 0.10). The total antioxidant status (TAS) level, in serum was significantly lower in patients than healthy controls (SMD = − 0.98, 95%CI = -1.57 to -0.39, p = 0.001). In addition, RAS patients had higher levels of serum Malondialdehyde (MDA), Serum total oxidant status, and serum oxidative stress index than healthy controls (SMD = 2.11, 95%CI = 1.43–2.79, p < 0.001, SMD = 1.53, 95%CI = 0.34–2.72, p = 0.01, and SMD = 1.25, 95%CI = 0.25–2.25, p = 0.014, Respectively); However, salivary MDA and TAS, and serum uric acid, vitamin E and C, and reduced glutathione levels of patients with RAS were not different from that of healthy controls. Conclusions: The relationship between oxidative stress and RAS is well established in this meta-analysis. Although the molecular processes underlying the etiology of this pathology remain unknown, evidence indicating oxidative stress has a significant role in the pathogenesis of RAS has been revealed. [ABSTRACT FROM AUTHOR]

Many high-altitude plants, such as Hedyotis aspera, need to be explored for their possible medicinal value. The current study explored the protective effect of Hedyotis aspera methanolic extract whole plant (HAME) against gentamicin-induced nephrotoxicity in rats. It profiled their phytocontents using HPLC-QTOF-MS/MS analytic methods. The LC-MS analysis of HAME revealed 27 compounds. Eight compounds followed Lipinski's rule of five and were found to be potential TNF-α inhibitors with binding affinities of −6.9, −6.3, −6.3, and −6.3 Kcal/mol, such as 14,19-Dihydroaspidospermatine, coumeroic acid, lycocernuine and muzanzagenin. All potential compounds were found to be safe according to the ADMET analysis. The in vitro 2,2-diphenyl-1-picrlhydrazyl (DPPH) assay assessed the antioxidant activity. The nephroprotective activity was assessed in rats using a gentamicin-induced nephrotoxicity model. The in vivo analysis involved histological examination, tissue biochemical evaluation, including a kidney function test, catalase activity (CAT), reduced glutathione (GSH) levels, superoxide dismutase (SOD), and the inflammatory mediator TNF-α. Based on DPPH activity, HAME showed a scavenging activity IC50 of 264.8 ± 1.2 µg/mL, while results were compared with a standard vitamin C IC50 of 45 ± 0.45 µg/mL. Nephrotoxicity was successfully induced, as shown by elevated creatinine and uric acid levels, decreased kidney antioxidant levels, and increased TNF-α in gentamicin-treated rats. The HAME treatment significantly reduced serum creatinine and uric acid levels, increased GSH (p < 0.01 **), CAT (p < 0.01 **), and SOD (p < 0.001 ***), and decreased TNF-α (p < 0.001 ***) in nephrotoxic rats. The histopathological examination of the groups treated with HAME revealed a notable enhancement in the structural integrity of the kidneys as compared to the group exposed to gentamicin. Biochemical, histopathological, and phytochemical screening of HAME suggests that it has nephroprotective potential, owing to the presence of 14,19-Dihydroaspidospermatine, coumeroic acid, lycopene, and muzanzagenin. [ABSTRACT FROM AUTHOR]

Simultaneous determination of small biologically important molecules is more significant for monitoring several diseases at physiological pH. Uric acid (C5H4N4O3) and ascorbic acid (C6H8O6), for instance, were once regarded as crucial components in the physiological processes of humans since they coexist in numerous biological matrices regularly, and monitoring their concentrations simultaneously indicates diseases like gout. In the present work, the gold nanoparticles (AuNPs) were assembled on a glassy carbon electrode (GCE) using electrodeposition of Au3+ ions for the simultaneous determination of C5H4N4O3 and C6H8O6. The deposited AuNPs were characterized using UV–visible spectroscopy, XPS, XRD, and AFM. Morphological analysis depicted that the particles are spherical with a size of 32 nm, and the particles are uniformly distributed on the electrode surface. The formation of gold oxide and its reduction peaks in cyclic voltammetry revealed the effective deposition of AuNPs on the GCE surface. The catalytic activity AuNPs modified GCE was analyzed by probing the oxidation of C5H4N4O3 and C6H8O6 at physiological pH (pH 7.2). The present modified electrode greatly enhanced the oxidation peak currents, and the potential of oxidation is also shifted to less positive potential compared to bare GCE. The AuNPs/GCE was used to determine C5H4N4O3 in the presence of a 50-fold high concentration of C6H8O6. The detection of 40 nM C5H4N4O3 was achieved using amperometry and a detection limit of 1.8 × 10–9 M (Signal/Noise = 3) was observed for the determination of uric acid in the concentration range from 4 × 10–8 to 4 × 10–5 M. [ABSTRACT FROM AUTHOR]

Hyperuricemia and its complications are severe risks to human health. Dietary intervention is considered an essential part of the management of hyperuricemia. Studies have reported that the intake of antioxidants has a positive effect on hyperuricemia. Here, we collected data from 8761 participants of the National Health and Nutrition Examination Survey for this analysis. Daily intakes of vitamins A, C, and E; manganese; selenium; and zinc were calculated as the composite dietary antioxidant index (CDAI). The participants were divided into four groups (Q1, Q2, Q3, and Q4) according to the CDAI. Univariate analysis was used to assess the association of covariates with hyperuricemia. The association between the CDAI and hyperuricemia was evaluated using multinomial logistic regression, and its stability was determined by stratified analysis. Our results revealed that the CDAI has a significant negative association with hyperuricemia (Q2: 0.81 (0.69, 0.95); Q3: 0.75 (0.62, 0.90); Q4: 0.65 (0.51, 0.82); P < 0.01). The results of stratified analysis emphasize that this association between CDAI and hyperuricemia is stable. In conclusion, this study suggested a negative association between the CDAI and hyperuricemia. [ABSTRACT FROM AUTHOR]

A Prussian blue analogue with cobalt (Na2‐xCo[Fe(CN)6]1‐y, PB‐Co), which is often used as sodium‐ion battery material, was found to be an excellent sensing material toward some biomolecules by calcination. PB‐Co calcined at 750 °C for 1 h (PB‐Co750‐1) has the improved defects to facilitate the adsorption and the catalytic oxidation of ascorbic acid (AA), dopamine (DA) and uric acid (UA). PB‐Co750‐1 modified on screen printed carbon electrode (SPE) for the ultrasensitively simultaneous determination of AA, DA and UA demonstrates the wide linear range, the low limit of detection (LOD) and the good reproducibility. In addition, the redox of the analytes was confirmed as the diffusion‐controlled process via the kinetic study. The recoveries of AA, DA and UA in real samples were found between 91 % to 114 %. AA and UA in tablets, serums and urines could be determined by PB‐Co750‐1/SPE with the satisfactory results. [ABSTRACT FROM AUTHOR]

A 3D graphene foam made of interconnected multilayer graphene flakes was produced on optical fibres (OF) by laser-induced transformation of a polyimide (PI) film coated on the OF cladding. This material, known as laser-induced graphene (LIG), was explored in the electrochemical detection and quantification of dopamine (DA) at physiologically relevant concentrations in the presence of the most relevant interfering molecules in biological fluids, ascorbic acid (AA) and uric acid (UA). The measured limit of detection is 100 nM, the linear range is 0.1 to 5.0 μM and a maximum sensitivity of 5.0 µA µM−1 cm−2 was obtained for LIG decorated with Pt nanoparticles (NPs). Moreover, immunity to AA and UA interference and to fouling was attained by decorating the LIG electrode with Pt NPs and coating it with Nafion. These figures of merit underline the potential of these sensors for the quantification of physiologically relevant concentrations of DA in biological fluids, paving the way for the development of hybrid electrochemical/optical sensing actuating platforms in a lab-on-fibre configuration, with relevant applications in biomedical engineering. The advantages of this hybrid arrangement include the possibility of in situ counterproofing, extended measuring ranges, photoelectrochemical detection and the probing of inaccessible places. This elegant approach can also provide a simple and cost-effective way to fabricate biomedical devices with extended functionality, such as medical optical probes with added electrochemical capabilities and optogenetics combined with local electrochemical detection, among others. [ABSTRACT FROM AUTHOR]

Uric acid is an independent risk factor for socially important diseases, such as chronic heart failure and chronic kidney disease. The review summarizes current data on the impact of nutrition as a presumably modifiable factor into the development of hyperuricemia and gout. The authors describe biochemical mechanisms underlying hyperuricemia and present data on the influence of excessive intake of fructose, purines, and various alcohol-containing drinks on the risk of gout. Favorable impact of vitamin C supplements, coffee, cherry juice, some chemical elements (magnesium, zinc, and copper) on uric acid levels has been shown, as well as the impact of intake of low fat dairy products, polyphenols, food fibers, and omega-3 polyunsaturated fatty acids on the incidence of hyperuricemia. The information presented in the review can be used in clinical practice for preparation of an individualized nutritional plan aimed at normalization of uric acid levels. This would minimize the use of agents affecting the synthesis of uric acid and slow down the progression of chronic heart failure and chronic kidney disease.

High uric acid is associated with gout, hypertension, metabolic syndrome, cardiovascular disease, and kidney disease. URAT1 (SLC22A12), originally discovered in mice as Rst, is generally considered a very selective uric acid transporter compared to other closely-related kidney uric acid transporters such as OAT1 (SLC22A6, NKT) and OAT3 (SLC22A8). While the role of URAT1 in regulating human uric acid is well-established, in recent studies the gene has been linked to redox regulation in flies as well as progression of renal cell carcinoma. We have now identified over twenty metabolites in the Urat1 knockout that are generally distinct from metabolites accumulating in the Oat1 and Oat3 knockout mice, with distinct molecular properties as revealed by chemoinformatics and machine learning analysis. These metabolites are involved in seemingly disparate aspects of cellular metabolism, including pyrimidine, fatty acid, and amino acid metabolism. However, through integrative systems metabolic analysis of the transcriptomic and metabolomic data using a human metabolic reconstruction to build metabolic genome-scale models (GEMs), the cellular response to loss of Urat1/Rst revealed compensatory processes related to reactive oxygen species handling and maintaining redox state balances via Vitamin C metabolism and cofactor charging reactions. These observations are consistent with the increasingly appreciated role of the antioxidant properties of uric acid. Collectively, the results highlight the role of Urat1/Rst as a transporter strongly tied to maintaining redox homeostasis, with implications for metabolic side effects from drugs that block its function. [ABSTRACT FROM AUTHOR]

A simple electrochemical sensor based on electrochemically synthesized Fe3O4 nanoparticles was constructed by an ink with the nanoparticles, isopropanol, NAFION and carbon Vulcan to detect dopamine, uric acid and ascorbic acid. The electrocatalytic activity of the nanoparticles for the oxidation of the analyte molecules was examined by means of cyclic voltammetry and square wave voltammetry. The parameters controlling the performance of the sensor were optimized, such as the amount of Fe3O4 nanoparticles (1, 2, 3, 5, 8, 10 mg), amount of binder (5, 10, 15 µL) and carbon Vulcan in the ink (4, 6, 8 mg). The temperature was maintained at 25 °C and the pH was 7.5 with buffer phosphate. The optimal sensor conditions were 8 mg magnetite, 4 mg carbon Vulcan and 5 µL of NAFION@ 117. The calibration curves for the three analytes were determined separately, obtaining linear ranges of 10–100, 20–160 and 1050–2300 µM and limits of detection of 4.5, 14 and 95 µM for dopamine, uric acid and ascorbic acid, respectively. This electrochemical sensor has also shown significant sensitivity and selectivity without interference from the three analyte molecules presented simultaneously in solution. This sensor was applied for the detection of these molecules in real samples. [ABSTRACT FROM AUTHOR]

The current review paper portrays the important link of different nutrients like trace elements, proteins, fatty acids, vitamins, and amino acids with the immune system as well as information related to metabolic paradoxes. Optimum working of the metabolic system is essential because it gives various types of supplements to the human body and aid in chemical pathways. Here related data have been retrieved from two databases i.e., PubMed and Google scholar to grasp detailed knowledge about micronutrients and nutrients as well as their association in the metabolic system. Like protein play important role in the normal development of different immune components, amino acids including alanine, Arginine, and glutamic acid properly control the movement of neutrophils, macrophages, and cytokines. While fatty acids act as an anti-inflammatory agent because they possess the ability to inhibit the expression of the MHC class. Apart from these, many essential molecules like uric acid, proteins, calcium, lanolin are also obtained as end products after catabolic and anabolic reactions, and it was found that the uric acid paradox has a cancer inhibitory role. Additionally, TGF and IL-6 paradoxes have a role in the development of tumors, the onset of diabetes, and low-grade inflammatory disorders respectively. However, the entire functioning of metabolic processes depends upon daily diet because humans get the important nutrient from the diet which further vital role in the immune system. Moreover, it was also observed that calcium paradox is related to heart disorders because high calcium accumulation leads to cardiac disorders. Thus, the complete knowledge about these essential components as well as metabolic paradoxes is very important due to their antagonistic role to plan better and improved therapeutic strategies for various diseases.

In this study, we reported the construction of Gold Nanospike (AuNS) structures on the surface of screen-printed carbon electrode (SPCE) used for non-enzymatic electrochemical detection. This modification was prepared with a one-step electrodeposition method by controlling the electrodeposition parameters, such as applied potential and deposition time, via Constant Potential Amperometry (CPA). Those parameters and precursor solution concentration were varied to investigate the optimum electrodeposition configuration. The results confirmed that AuNS were homogenously deposited and well-dispersed on the working electrode surface of SPCE. The AuNS-modified SPCE was implemented as a non-enzymatic sensor toward dopamine and could enhance the electrocatalytic ability compared with the bare SPCE. Further examination shows that the sensing performance of the AuNS-modified SPCE produced an increase in electrochemical surface area (ECSA) at 17.25 times higher than the bare electrode, a sensitivity of 0.056 µA mM−1 cm−2 with a wide linear range of 0.2–50 µM and a detection limit of 0.33 µM. In addition, AuNS-modified SPCE can selectively detect dopamine among other interfering analytes such as ascorbic acid, urea, and uric acid, which commonly coexist in the body fluid. This work demonstrated that AuNS-modified SPCE is a prospective sensing platform for non-enzymatic dopamine detection. [ABSTRACT FROM AUTHOR]

Nitrogen (N) doping is a well-known approach that can be effectively used to tune the properties of graphene-supported materials. The current attempt followed a simple hydrothermal protocol for the fabrication of N-doped graphene sheets (N-GSs). The N-GSs were subsequently applied to modify the surface of a glassy carbon electrode (GCE) for a dopamine (DA) electrochemical sensor (N-GSs/GCE), tested on the basis of differential pulse voltammetry (DPV). The findings highlighted a limit of detection (LOD) as narrow as 30 nM and a linear response in the concentration range between 0.1 and 700.0 μM. The modified electrode could successfully determine DA in the co-existence of uric acid (UA) and ascorbic acid (AA), the results of which verified the potent electrocatalytic performance of the proposed sensor towards AA, DA, and UA oxidation, and three distinct voltammetric peaks at 110, 250, and 395 mV via DPV. The practical applicability of the as-developed N-GSs/GCE sensor was confirmed by sensing the study analytes in real specimens, with satisfactory recovery rates. [ABSTRACT FROM AUTHOR]

An enzyme-free terahertz uric acid sensor based on a metallic slot array metamaterial was proposed and realized both theoretically and experimentally. The sensing model was verified in simulation and femtosecond laser processing technology was employed to ablate slots in the copper plate to fabricate metamaterials. Analytes were tested with liquid phase deposition on the metamaterial by a terahertz frequency domain spectroscopy system. Gradient concentrations of uric acid, ascorbic acid, and a mixture of them were measured separately with a good linear response. A significant decrease in sensitivity was observed in the ascorbic acid assay compared with the uric acid assay. The test results of the mixture also proved that our device is resistant to ascorbic acid. It is a simple and effective method for monitoring uric acid concentrations and the strategy of eliminating interference while modulating the resonance peak location mentioned here can be rationally projected for the development of other sensors. [ABSTRACT FROM AUTHOR]

In this paper, an ultra-sensitive glassy carbon electrode modified with β-cyclodextrin and graphene oxide (β-CD-GO/GCE) has been prepared for the detection of biomolecules [ascorbic acid (AA), dopamine (DA) and uric acid (UA)] in aqueous solution at μM level. The three biomolecules (AA, DA and UA) can be simultaneously detected by the modified electrodes, and the electrical signals corresponding to various biomolecules can be identified clearly in cyclic voltammetry and differential pulse voltammetry curves. The simultaneous detection limits of AA, DA, UA were 4.58, 1.56, 1.27 μM, respectively. This ultra-sensitivity should be attributed to the formation of host–guest complexes between β-CD and the biomolecules. Furthermore, the anti-interference experiments indicated the β-CD-GO/GCE exhibited satisfactory selective recognition performance. [ABSTRACT FROM AUTHOR]

In the present study, a rapid, practical, selective and sensitive method was proposed for simultaneous determination of dopamine (DA) and uric acid (UA). Kinetic profiles of analytes were recorded and transformed by different mother wavelets. The contribution of ascorbic acid was neglected using mean centering of data before transformation. The concentrations range were 1.0–60.0 μmol L−1 and 7–40.0 μmol L−1, with detection limit of 0.06 and 0.30 μmol L−1 for uric acid and dopamine, respectively. The results of sym8 and db4 mother wavelets showed that proposed method creates a most selective and sensitive determination without using initial separation steps. The obtained results by CWT-sym8 and CWT-db4 were compared with partial least squares (PLS) results. The simultaneous quantitation of DA and UA with the proposed method was successfully applied in different urine and serum samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new, highly sensitive and selective sensor based on CuAl-LDH has been developed for electrochemical determination of dopamine. • A one-step coprecipitation method was used to prepare Cu-Al layered double hydroxide composites. • The propsed sensor indicated wide linear range (4.194–1151.54 μM) and low detection limit (0.33 μM). • Dopamine in pharmaceutical ampoules and plasma samples was measured satisfactorily using this sensor. This study provides a unique electrochemical sensor that exhibits both excellent sensitivity and selectivity, while also being environmentally friendly. The CuAl-LDH/GCE sensor, proposed as the recommended sensor, was synthesized using a straightforward one-step co-precipitation procedure. It was first used to measure dopamine levels using differential pulse voltammetry. At the ideal pH level of 8, dopamine has a positive charge, but ascorbic acid and uric acid have a negative charge. LDH, on the other hand, carries a negative charge and exhibits high electrostatic attraction towards dopamine, but is electrostatically repelled by negatively charged ascorbic acid and uric acid. Hence, CuAl-LDH/GCE has the potential to specifically ascertain the existence of dopamine in the presence of these particular species. The examination of the composition and morphology of CuAl-LDH was conducted using various analytical techniques, including scanner electron microscopy (FESEM), transmission electron microscope (TEM), element mapping (MAP), Fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDX), Brunauer Emmett Teller (BET), X-ray photoelectron diffraction (XRD), and Raman techniques. Under ideal circumstances, the calibration graph of dopamine was generated using differential pulse voltammetry. A linear range of 4.194–1151.54 μM was achieved for dopamine, with a limit of detection of 0.33 μM. The findings of the study indicate that the sensor created for dopamine determination has exceptional stability, repeatability, and reproducibility. The sensor that was presented was effectively used for the measurement of dopamine in both pharmaceutical ampoules and human plasma samples. [ABSTRACT FROM AUTHOR]

Background Short-term randomized trials suggest that a 500 mg/d vitamin C supplement reduces serum urate, whereas observational studies show vitamin E is inversely associated with gout risk. Objectives We evaluated the effect of supplemental vitamin C (prespecified primary exposure) and vitamin E (prespecified secondary exposure) on new diagnoses of gout. Methods We performed a post hoc analysis of data from the Physicians' Health Study II, a randomized, double-blind, placebo-controlled factorial trial of randomized vitamin C (500 mg/d) and vitamin E (400 IU every other day). The primary outcome was new gout diagnoses, self-reported at baseline and throughout the follow-up period of ≤10 y. Results Of 14,641 randomly assigned male physicians in our analysis, the mean age was 64 ± 9 y; 1% were Black, and 6.5% had gout prior to randomization. The incidence rate of new gout diagnoses during follow-up was 8.0 per 1000 person-years among those assigned vitamin C compared with 9.1 per 1000 person-years among those assigned placebo. The vitamin C assignment reduced new gout diagnoses by 12% (HR: 0.88; 95% CI: 0.77, 0.99; P  = 0.04). These effects were greatest among those with a BMI <25 kg/m 2 (P -interaction = 0.01). Vitamin E was not associated with new gout diagnoses (HR: 1.05; 95% CI: 0.92, 1.19; P  = 0.48). Conclusions Vitamin C modestly reduced the risk of new gout diagnoses in middle-aged male physicians. Additional research is needed to determine the effects of higher doses of vitamin C supplementation on serum urate and gout flares in adults with established gout. The Physicians' Health Study II is registered at clinicaltrials.gov (identifier: NCT00270647). [ABSTRACT FROM AUTHOR]

Current diagnostics call for rapid, sensitive, and selective screening of physiologically important biomarkers. Point-of-care (POC) devices for the rapid, reliable, and easy acquisition of bioinformation at, or near the patient, offer opportunities for better healthcare management. Electrochemical biosensors with high sensitivity and ease of miniaturization are advantageous for such applications. We report a photolithographically micropatterned PEDOT:PSS and silk protein-based fully organic 3-electrode sensor (O3ES) for ultralow volume (single drop—10 µL) detection of analytes in whole blood. The O3ES produces reliable electrochemical signals in whole blood from a mouse model with minimal biofouling interference. The O3ES is demonstrated as a portable device for the simultaneous detection of dopamine, ascorbic acid and uric acid using voltammetry techniques. The O3ES displays excellent sensitivity towards each analyte in whole blood, and in the presence of each other. The water-based, ambient processing of the sensors allows the immobilization of enzymes in the organic working electrode. Amperometric detection of uric acid via uricase with high sensitivity in whole blood is demonstrated. Finally, the performance of the O3ES under enzymatic degradation is studied by monitoring sensitivity over an operating lifetime of ~14 days. This work demonstrates the realization of low-cost, disposable POC sensors capable of detecting blood metabolites using ultralow sample volumes. [ABSTRACT FROM AUTHOR]

Selectivity of dopamine (DA), uric acid (UA), and ascorbic acid (AA) is an open challenge of electrochemical sensors in the field of biosensing. In this study, two selective mechanisms for detecting DA, UA, and AA biomolecules on the pristine boron nitride nanosheets (BNNS) and functionalized BNNS with tryptophan (Trp), i.e., Trp@BNNS have been illustrated through density functional density (DFT) calculation and charge population analysis. Our findings reveal that the adsorbed biomolecules on Trp@BNNS indicate the less sensitivity factor of biomolecule separation than the functionalized biomolecules with Trp (Trp@biomolecule) adsorbed on pristine BNNS. From the calculations, strong adsorption of Trp@biomolecule on the pristine substrate corresponds to enhancing of electron charge transfer and electrical dipole moment. Our analysis is in good agreement with the previous theoretical and experimental results and suggests new pathway for electrode modification for electrochemical biosensing. [ABSTRACT FROM AUTHOR]

In previous studies, the increasing clinical importance of nonalcoholic fatty liver disease (NAFLD) has been recognized. However, the specific therapeutic strategies or drugs have not been discovered. Vitamin C is a water-soluble antioxidant and is a cofactor in many important biosynthesis pathways. Recently, many researchers have reported that the mega-dose vitamin C treatment had positive effects on various diseases. However, the precise relationship between mega-dose vitamin C and NAFLD has not been completely elucidated. This study has been designed to discover the effects of mega-dose vitamin C on the progression of NAFLD. Twelve-week-old wild-type C57BL6 mice were fed chow diets and high-fat and high-fructose diet (fast-food diet) ad libitum for 11 weeks with or without of vitamin C treatment. Vitamin C was administered in the drinking water (1.5 g/L). In this study, 11 weeks of the mega-dose vitamin C treatment significantly suppressed the development of nonalcoholic steatohepatitis (NASH) independently of the catabolic process. Vitamin C supplements in fast-food diet fed mice significantly decreased diet ingestion and increased water intake. Histopathological analysis revealed that the mice fed a fast-food diet with vitamin C water had a mild renal injury suggesting osmotic nephrosis due to fructose-mediated purine derivatives. These data suggest that the mega-dose vitamin C treatment suppresses high-fructose-diet-mediated NAFLD progression by decreasing diet ingestion and increasing water intake. [ABSTRACT FROM AUTHOR]

Graphene has been considered as an excellent biochemical sensors' substrate material because of its excellent physical and chemical properties. Most of these sensors have employed enzymes, antibodies, antigens, and other biomolecules with corresponding recognition ability as recognition elements, to convert chemical signals into electrical signals. However, oxidoreductase enzymes that grow on graphene surfaces are affected significantly by the environment and are easily inactivated, which hinders the further improvement of detection sensitivity and robusticity. A gold-boosted graphene sensor was fabricated by the in situ electrochemical deposition of inorganic gold nanoparticles on vertical graphene nanosheets. This approach solves the instability of biological enzymes and improves the detection performance of graphene-based sensors. The uric acid sensitivity of the gold-boosted electrode was 6230 µA mM−1 cm−2, which is 6 times higher than the original graphene electrode. A 7 h GNSs/CC electrode showed an impressive detection performance for ascorbic acid, dopamine, and uric acid, simultaneously. Moreover, it exhibited a reliable detection performance in human serum in terms of uric acid. The possible reason could be that the vertical aliened graphene nanosheet acts as a reaction active spot. This 3D graphene-nanosheet-based doping approach can be applied to a wide variety of inorganic catalytic materials to enhance their performance and improve their durability in aspects such as single-atom catalysis and integration of multiple catalytic properties. [ABSTRACT FROM AUTHOR]

The development of electrochemical sensors with high sensitivity for the simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) is urgently desirable in clinical medicine. However, the challenge lies in achieving simultaneous detection due to their closely oxidation potentials. In this work, we present the synthesis of a composite material comprised of in-situ grown TiO 2 nanowires (NWs) on a Ti 3 C 2 T x substrate (Ti 3 C 2 T x /TiO 2 NWs) through a facile alkali process. By modifying a glassy carbon electrode (GCE) with Ti 3 C 2 T x /TiO 2 NWs (Ti 3 C 2 T x /TiO 2 NWs/GCE), it showed excellent electrocatalytic activity for the simultaneous detection of AA/DA/UA by regulating the surface functional groups of Ti 3 C 2 T x. Remarkably, the Ti 3 C 2 T x /TiO 2 NWs/GCE enabled simultaneous detection of AA in the range of 300–1800 μM, DA in the range of 2–33 μM, and UA in the range of 2–33 μM. The limits of detection (LODs) for AA, DA, and UA were estimated as 6.61 μM, 0.093 μM, and 0.038 μM, respectively. The proposed Ti 3 C 2 T x /TiO 2 NWs/GCE demonstrated good stability, high selectivity, reliable reproducibility and satisfactory recovery results in real samples, making it a promising electrochemical sensor for the detection of AA, DA, and UA. This work offers a new perspective for human health monitoring, paving the way for advancements in this field. • Ti 3 C 2 T x /TiO 2 NWs composite is synthesized in situ by simple alkali treatment. • Alkali process adjust surface functional groups and electrical properties of Ti 3 C 2 T x. • The sensor realizes simultaneous determination of AA/DA/UA with good anti-interference ability. • Higher specific surface area and the formed Ti 3 C 2 T x /TiO 2 heterojunctions cause the excellent properties of sensor. [ABSTRACT FROM AUTHOR]

The role of uric acid during primate evolution has remained elusive ever since it was discovered over 100 years ago that humans have unusually high levels of the small molecule in our serum. It has been difficult to generate a neutral or adaptive explanation in part because the uricase enzyme evolved to become a pseudogene in apes thus masking typical signals of sequence evolution. Adding to the difficulty is a lack of clarity on the functional role of uric acid in apes. One popular hypothesis proposes that uric acid is a potent antioxidant that increased in concentration to compensate for the lack of vitamin C synthesis in primate species ∼65 Ma. Here, we have expanded on our previous work with resurrected ancient uricase proteins to better resolve the reshaping of uricase enzymatic activity prior to ape evolution. Our results suggest that the pivotal death-knell to uricase activity occurred between 20 and 30 Ma despite small sequential modifications to its catalytic efficiency for the tens of millions of years since primates lost their ability to synthesize vitamin C, and thus the two appear uncorrelated. We also use this opportunity to demonstrate how molecular evolution can contribute to biomedicine by presenting ancient uricases to human immune cells that assay for innate reactivity against foreign antigens. A highly stable and highly catalytic ancient uricase is shown to elicit a lower immune response in more human haplotypes than other uricases currently in therapeutic development. [ABSTRACT FROM AUTHOR]

An innovative, ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene) (OPEDOT), gold nanoparticles (AuNPs), and electrochemically reduced graphene oxide (ERGO) was prepared on a glassy carbon electrode (GCE) (OPEDOT–AuNPs–ERGO/GCE) through homogeneous chemical reactions and heterogeneous electrochemical methods. The morphology, composition, and structure of this nanocomposite were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the OPEDOT–AuNPs–ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(III) chloride redox probe systems. This modified electrode shows excellent electro-catalytic activity for dopamine (DA) and uric acid (UA) under physiological pH conditions, but inhibits the oxidation of ascorbic acid (AA). Linear voltammetric responses were obtained when DA concentrations of approximately 4.0–100 μM and UA concentrations of approximately 20–100 μM were used. The detection limits (S/N=3) for DA and UA were 1.0 and 5.0 μM, respectively, under physiological conditions and in the presence of 1.0 mM of AA. This developed method was applied to the simultaneous detection of DA and UA in human urine, where satisfactory recoveries from 96.7% to 105.0% were observed. This work demonstrates that the developed OPEDOT–AuNPs–ERGO ternary nanocomposite, with its excellent ion-selectivity and electro-catalytic activity, is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies. [Display omitted] • Facile preparation of graphene-based hybrid composite OPEDOT–AuNPs–ERGO onto GCE. • The OPEDOT–AuNPs–ERGO/GCE was endued with excellent electrocatalytic activity and ion-selectivity. • The OPEDOT–AuNPs–ERGO/GCE was found highly selective and sensitive determination of DA and UA in the presence of AA. • The method is expected to be applied to the detection of DA and UA under physiological and pathological conditions. [ABSTRACT FROM AUTHOR]

In previous studies, the increasing clinical importance of nonalcoholic fatty liver disease (NAFLD) has been recognized. However, the specific therapeutic strategies or drugs have not been discovered. Vitamin C is a water-soluble antioxidant and is a cofactor in many important biosynthesis pathways. Recently, many researchers have reported that the mega-dose vitamin C treatment had positive effects on various diseases. However, the precise relationship between mega-dose vitamin C and NAFLD has not been completely elucidated. This study has been designed to discover the effects of mega-dose vitamin C on the progression of NAFLD. Twelve-week-old wild-type C57BL6 mice were fed chow diets and high-fat and high-fructose diet (fast-food diet) ad libitum for 11 weeks with or without of vitamin C treatment. Vitamin C was administered in the drinking water (1.5 g/L). In this study, 11 weeks of the mega-dose vitamin C treatment significantly suppressed the development of nonalcoholic steatohepatitis (NASH) independently of the catabolic process. Vitamin C supplements in fast-food diet fed mice significantly decreased diet ingestion and increased water intake. Histopathological analysis revealed that the mice fed a fast-food diet with vitamin C water had a mild renal injury suggesting osmotic nephrosis due to fructose-mediated purine derivatives. These data suggest that the mega-dose vitamin C treatment suppresses high-fructose-diet-mediated NAFLD progression by decreasing diet ingestion and increasing water intake.

The integration of the enzymes on the solid electrode surfaces is an indispensable step for the construction of the bioelectrochemical electrode. In the current work, the blend nanofibers consisting of poly (vinyl alcohol) and poly(ethyleneimine) were deposited by the electrospinning method on an H2O2-sensitive modified glassy carbon electrode. Glucose oxidase was immobilized on the glutaraldehyde-activated blend nanofibers. Bioelectrochemical electrode displayed a good linear response to the glucose concentration ranges with two separate calibration curves, from 2 to 8 mmol L−1 and from 10 to 30 mmol L−1. Besides, it showed a high anti-interference performance against ascorbic and uric acids as well as long-term storage stability over 63 days. Moreover, analysis results in a diluted human serum sample showed that the prepared bioelectrochemical electrode has the ability to measure glucose in real samples. [ABSTRACT FROM AUTHOR]

Red amaranth (Amaranthus tricolor L.) contains phytochemicals that are important for human health, however it also contains oxalate that may cause uric acid problem in human health. This experiment was carried out to evaluate the effect of salicylic acid (SA) on growth, oxalate, chlorophyll, and vitamin C contents in red amaranth. Red amaranth seeds were germinated in a plastic pot containing a mixture of top soil and organic fertilizer. Three week-old seedlings were applied with SA of 0 M (control), 10-8, 10-6, 10-4 or 10-2 M. Five replicates were prepared for each treatment. Growth parameters observed were plant height, fresh weight, and dry weight of plant. The Ca-oxalate crystal density was determined by observing stem section under the microscope. Chlorophyll and oxalic acid content were determined by spectrophotometer method, whereas vitamin C content was determined by titration method. The results showed that plant height and root length were tend to decline by SA application, however SA of 10-6 M significantly increased chlorophyll, carotenoid and vitamin C content. All concentrations of SA applied were able to reduce oxalic acid content and Ca-oxalate crystal density in stem. It can be inferred that application of SA generally enhances nutrient quality of red amaranth. [ABSTRACT FROM AUTHOR]

A fresh strategy based on two-step electrochemical reduction for the fabrication of palladium nanoparticles/reduced oxide nanocomposite-modified glass carbon electrode (PdNPs/rGO/GCE) was established in this study. Field emission scanning electron microscopy (FESEM) images showed that spherical PdNPs were evenly distributed on the surface of rGO-modified electrode (rGO/GCE), and the introduction of PdNPs has no effect on the morphology of rGO. Electrochemical impedance spectroscopy (EIS) studies revealed that the conductivity of PdNPs/rGO/GCE was higher than that of rGO/GCE and bare GCE. The electrochemical performances of PdNPs/rGO/GCE sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry using ascorbic acid (AA), dopamine (DA), and uric acid (UA) as analytes. At the optimized conditions, wide linear ranges of 0.5–3.5 mM (R2 = 0.99), 3–15 μM (R2 = 0.99) and 15–42 μM (R2 = 0.99), and 0.3–1.4 mM (R2 = 0.99) towards AA, DA, and UA in ternary mixture were observed, respectively. In addition to superior anti-interference capability, fast response (≤5 s), excellent reproducibility, and good long-term stability were also given by this sensor. These results suggested that PdNPs/rGO/GCE is promising for the simultaneous detection of AA, DA, and UA in practical application. [ABSTRACT FROM AUTHOR]

Electrochemical sensors have been prepared using pristine and activated multi-walled carbon nanotubes on glassy carbon electrode. The detection of dopamine in the presence of ascorbic acid was tested by square wave voltammetry and cyclic voltammetry. Best results were obtained for glassy carbon modified with activated carbon nanotubes electrodes. A linear dependence between current intensities and dopamine concentrations is found in both the absence/presence of ascorbic acid, in the range of 4-100 µM / 6-100 µM, with detection and quantification limits of 0.44 / 0.64 and 1.45 / 2.14 µM, respectively and high sensitivity. The developed electrodes also showed very good performance in separating the oxidation potentials of ascorbic acid, dopamine and uric acid, with peak potential differences of 200 and 170 mV. Dopamine detection in synthetic solutions in the presence of both ascorbic and uric acid gave recovery rates of 98%, indicating that the method is reliable. [ABSTRACT FROM AUTHOR]

A simple Co3O4 modified carbon paste electrode (CPE) was developed as an electrochemical sensor for the selective detection and quantification of dopamine (DA) via fastest synthesis and fabrication methods. The solution combustion method and bulk modification techniques were sequentially used for the preparation of the sensor. The modifier was characterized using different techniques such as PXRD, FT-IR, SEM and TG-DSC. The fabricated sensor shows a wide linear dynamic range of 80 µM-300 nM, low detection limit, excellent reproducibility and high stability. The differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques were extensively used for the electrochemical studies. The same electrode was used for detecting DA in the solution of coexisting ascorbic acid (AA) and uric acid (UA). Well resolved peaks and good current sensitivity of this electrochemical sensor extended its utility in determining DA in blood serum at physiological pH. [ABSTRACT FROM AUTHOR]

In this work, UV/Vis spectroelectrochemistry (SEC), in a thin-layer regime and parallel configuration, is selected to solve a complex mixture that contains dopamine (DA), ascorbic acid (AA) and uric acid (UA). These molecules, like many other biological compounds, are assuming a highly important place in analytical and biomedical fields due to the fundamental role that they play in human metabolism. In addition, low or high levels of these compounds are associated with diseases such as Parkinson's disease. For this reason, the quantification of these biomolecules is becoming increasingly critical. However, some drawbacks must be overcome, because the three molecules coexist in the human body, and the species are subject to mutual interference. In fact, they are all oxidized at similar potentials, and their UV/Vis absorption bands overlap, greatly complicating their quantification. For this reason, derivative SEC together with suitable chemometric tools such as PARAFAC are proposed to solve this complex matrix. This technique allows us to separate the contribution of each of these molecules present in a sample and to quantify all of them, achieving high resolution and reproducibility. Besides, detection limits at the micromolar level are achieved for DA, AA and UA in mixture solutions. This work thus demonstrates the great potential for derivative potentiodynamic SEC combined with the appropriate chemometric tools in solving complex mixtures, a field where SEC is still taking the first steps. [ABSTRACT FROM AUTHOR]

A method with high sensitivity, good accuracy and fast response is of ever increasing importance for the simultaneous detection of AA, DA and UA. In this paper, a simple and sensitive electrochemical sensor, which based on the polyvinylpyrrolidone (PVP)-graphene composite film modified glassy carbon electrode (PVP-GR/GCE), was presented for detecting ascorbic acid (AA), dopamine (DA) and uric acid (UA) simultaneously. The PVP-GR/GCE has excellent electrocatalytic activity for the oxidation of AA, DA and UA. The second-order derivative linear sweep voltammetry was used for the electrochemical measurements. The peak potential differences of DA-AA, DA-UA, and UA-AA (measured on the PVP-GR/GCE) were 212, 130 and 342 mV respectively. Besides, the over potential of AA, DA and UA reduced obviously, so did the peak current increase. Under the optimum conditions, the linear ranges of AA, DA and UA were 4.0 μM–1.0 mM, 0.02–100 μM, and 0.04–100 μM, respectively. The detection limits were 0.8 μM, 0.002 μM and 0.02 μM for AA, DA, and UA. The electrochemical sensor presented the advantages of high sensitivity and selectivity, excellent reproducibility and long-term stability. Furthermore, the sensor was successfully applied to the analysis of real samples. [ABSTRACT FROM AUTHOR]

Au/CuO nanoparticles with a size range of 20–40 nm directly synthesized by solution plasma method in water have been successfully applied to the non-enzyme detection of glucose. The electrocatalytic activities of Au/CuO nanoparticles toward glucose were evaluated in an alkaline solution by cyclic voltammetry and real-time current method. Research results demonstrate that the biosensor modified by Au/CuO catalysts has a fast reaction time (< 3 s) and low detection limit (0.22 µM). There are two specific linear ranges of 0.22 µM–1 mM and 3 mM–18 mM, with the sensitivities of 172.45 µA mM−1 cm−2 and 63.66 µA mM−1 cm−2, respectively. Moreover, it also exhibited remarkable current response, good stability (87% after 50 days), superior reproducibility, and excellent selectivity in interfering species (such as D-fructose, ascorbic acid and uric acid). Therefore, the Au/CuO nanoparticles directly synthesized by solution plasma method can be implemented to the enzyme-free detection of glucose. [ABSTRACT FROM AUTHOR]

This experiment was conducted and aimed to reducing mortality and losing the weight of birds transported to the slaughter house through reducing or Transport stress removal and thus to reduce financial losses. 150 birds used almost equal weights that were divided into three treatment groups and by five replicates for each treatment is control treatment (T1) without giving anything and treatment with salicylic acid concentration 1 g / liter of drinking water (T2) and treatment with ascorbic acid (T3) concentration 0.5 g / Liter of drinking water provided 24 hours before its transport. The transport process resulted in a highly significant decrease (P ≤ 0.01) in body weight in treatment T1 as it reached 4.66%, while it reached 1.68 and 1.09% in treatment T2 and T3, respectively. The transport process led to an increase in body temperature, H / L ratio, the concentration of glucose, aspartate transaminase (AST) and alanine transaminase (ALT) in the blood serum, as the transport process led to a very significant decrease (P ≤ 0.01) in the cholesterol concentration, Uric acid, intestinal villi length and crypts depth. T2 and T3 treatments showed their ability to reduce transport stress, especially T3, where they outperformed T1 in most traits. It is concluded from the study that adding ascorbic acid by 0.5 g / L drinking water 24 hours before transporting the chicks to the slaughter house reduces the transport stress and lessen financial losses, so it is recommended to use it. [ABSTRACT FROM AUTHOR]

The "α,α-diphenyl-β-picrylhydrazyl radical (DPPH)" method from the estimation methods to determine the antioxidants activity in vitro, through the lowering the absorbance of DPPH with color changing from violet into yellow with increasing the strength of antioxidants activity. So, the results of this study show the uric acid is the strongest scavenging, then ascorbic acid when compared with other compounds used. But the reduced glutathione is the weakest although has acidic hydrogen. [ABSTRACT FROM AUTHOR]