Uric Acid In Saliva Research Articles

Engineering Interference-Removal and Target-Response Cascade Zones on Wood Channels for Straightforward Detection of Uric Acid in Saliva

Engineering Interference-Removal and Target-Response Cascade Zones on Wood Channels for Straightforward Detection of Uric Acid in Saliva

Synergistic enhancement of fluorescein-K3[Fe(CN)6] CL by MoO3-x NPs for sensitive and noninvasive detection of uric acid in saliva.

MoO3-x NPs was rapidly synthesized at room temperature by an easy stirring method. It was interestingto find that MoO3-x NPs induce OH- to generate active free radicals (ROS), which isa highly promising property in chemiluminescence (CL). Benefiting from the abundant oxygen vacancy, MoO3-x NPs adsorbsH2O2 and turn it into ·OH. The oxidase activity of fluorescein under visible light had already been reported, which catalyzesdissolved oxygen to become O2-· and continue to convert to H2O2. By creating the synergy effect with fluorescein, MoO3-x NPs strengthen the CL intensity of K3[Fe(CN)6]-fluorescein system significantly. Utilizing the quench effect of uric acid for the CL intensity, we developed a rapid, simple, and highly sensitive CL platform for uric acid detection. The linear range was 5-80µM and the detection limit (LOD) for uric acid was 3.11µM (S/N = 3). This work expanded the application of MoO3-x NPs in the CL field and developed a simple and highly sensitive CL sensing system to detect UA in human saliva.

Salivary uric acid sensor using the fordable “Finger‐Powered” microfluidic device

AbstractHere, we report a novel biosensing system using a finger‐powered microfluidic device, which is suitable for daily self‐testing of uric acid in saliva. To realize the rapid determination of salivary uric acid, the biosensing system measures directly from the paper‐based saliva sampling device. The microfluidic device has the diaphragm pump, the reagent reservoir, and the reaction cell in which the electrochemical uric acid biosensor is embedded. Once the microfluidic chip has been folded, the finger‐powered microfluidic device prepares the reagent containing the saliva, which is ready to measure. A wireless potentiostat for electrochemical measurement of uric acid with the biosensor was also developed. Combining these elements together, the whole process from saliva sampling to determination was completed in less than a minute (Sensitivity: 0.03 nA/μM). The measurement results were also consistent with that measured using a commercially available uric acid determination kit. Hence, our method is expected to have the potential to enhance the use of biochemical information in the field of healthcare IoT.

Assessment of pH level and uric acid in saliva before and after complete denture insertion

Background: Many factors influence the composition of saliva. The rate of secretion follows a circadian rhythm, decreasing during sleep and increasing during day. The present study was conducted to assess pH level and uric acid in saliva before and after complete denture insertion. Materials & Methods: 80 completely edentulous patients of both genders were divided into two groups of 40 each and each group was further divided into two groups of 20 each. Group I was age ranged 40-60 years contains two subgroups: group A1 for smokers and group A2 for non-smokers. Group II age ranged 61-80 years contains two subgroups: group B1 for smokers and group B2 for non-smokers. Saliva samples were collected from subjects immediately before the insertion of dentures and pH & uric acid estimation was done.Results: Out of 80 patients, males were 45 and females were 35. The mean pH of saliva before denture insertion was 6.7 and after denture insertion was 5.1. The difference was significant (P

Salivary Uric Acid Sensor using The Fordable ‘Finger-Powered' Microfluidic Device

Here, we report a novel biosensing system using a finger-powered microfluidic device, which is suitable for daily self-testing of uric acid in saliva. To realize the rapid determination of salivary uric acid, the biosensing system measures directly from the paper-based saliva sampling device. The microfluidic device has the diaphragm pump, the reagent reservoir, and the reaction cell in which the electrochemical uric acid biosensor is embedded. Once the microfluidic chip has been folded, the finger-powered microfluidic device prepares the reagent containing the saliva, which is ready to measure. A wireless potentiostat for electrochemical measurement of uric acid with the biosensor was also developed. Combining these elements together, the whole process from saliva sampling to determination was completed in less than a minute (Sensitivity: 0.03 nA/µM). The measurement results were also consistent with that measured using a commercially available uric acid determination kit. Hence, our method is expected to have the potential to enhance the use of biochemical information in the field of healthcare IoT.

A convenient sampling and noninvasive dried spot method of uric acid in human saliva: Comparison of serum uric acid value and salivary uric acid in healthy volunteers and hyperuricemia patients

Concentration of uric acid (UA) in serum is one of the markers used to diagnose gout and hyperuricemia. However, serum treatment and storage are cumbersome, and wounds are susceptible to infection. Therefore, a new sampling and analysis method using noninvasive biological samples has been developed, called the dried spot method of UA in human saliva (DSM-UHS). Saliva (5 μL) was dropped on filter paper (a spot with a diameter of 5 mm) containing hypoxanthine (IS) (5 μL) and dried at room temperature for 30 min. The filter paper was immersed in 200 μL of lithium carbonate solution and shaken in a block bath shaker for 5 min at 30 °C. Afterward, the extraction was concentrated and reconstituted with 100 μL of lithium carbonate solution analyzed by HPLC-UV. When comparing the concentration of UA in the human saliva of hyperuricemia patients (HPs) and with that of healthy volunteers (HVs), we observed the concentration of UA was higher in the HPs than in the HVs (p < 0.0001). In addition, the results showed a significant linear relationship between the content of UA in saliva and the content of UA in the serum (r = 0.6243). The content of UA in human saliva could indirectly reflect the content of UA in human serum. Then DSM-UHS could be used to determine the content of UA in the saliva of HVs and HPs. This study provides a new research method and strategy for the determination of human UA content and the clinical prewiring of hyperuricemia.

Spot test for determination of uric acid in saliva by smartphone-based digital images: A new proposal for detecting kidney dysfunctions

Changes in uric acid levels in biological fluids may be indicative of certain diseases related to kidney dysfunctions. Analytical methods recommended for the quantification of uric acid, such as high-performance liquid chromatography, are typically time-consuming and require high-cost equipment. In this study, a simple and cost-effective approach was developed for the determination of uric acid in saliva, by combining a spot test with smartphone-based digital image colorimetry. It was based on the reduction of Cu(II) to Cu(I) by uric acid, followed by complexation with 2,2′-biquinoline-4,4′-dicarboxylic acid (BCA), resulting in a violet product. Derivatization reactions and photometric measurements were both carried out in Eppendorf® tubes to facilitate the manipulation of biological samples. A smartphone camera and a free application (PhotoMetrix® 1.8) were used to capture the image and convert it to RGB values. Photometric measurements were based on reflected radiation in the G channel, corresponding to the complementary color of the product, yielding a linear response between 25 and 150 µmol L−1. The coefficient of variation (n = 10) and the limit of detection were 1.4% and 8 µmol L−1, respectively. Both reagent consumption (8.3 µg Cu(II), 3.8 mg ammonium acetate, and 156 µg BCA per determination) and waste volume (900 µL per determination) were minimized. The results agreed with those obtained by HPLC, demonstrating that the approach is a reliable alternative for large scale clinical analysis.

Non-invasive determination of uric acid in human saliva in the diagnosis of serious disorders.

This review summarizes and critically evaluates the published approaches and recent trends in sample pre-treatment, as well as both separation and non-separation techniques used for the determination of uric acid (UA) in saliva. UA is the final product of purine nucleotide catabolism in humans. UA concentrations in biological fluids such as serum, plasma, and urine represent an important biomarker of diseases including gout, hyperuricemia, or disorders associated with oxidative stress. Previous studies reported correlation between UA concentrations detected in saliva and in the blood. The interest in UA has been increasing during the past 20 years from a single publication in 2000 to 34 papers in 2019 according to MEDLINE search using term "uric acid in saliva". The evaluation of salivary UA levels can contribute to non-invasive diagnosis of many serious diseases. Increased salivary UA concentration is associated with cancer, HIV, gout, and hypertension. In contrast, low UA levels are associated with Alzheimer disease, progression of multiple sclerosis, and mild cognitive impairment.

Influence of Sampling Conditions, Salivary Flow, and Total Protein Content in Uric Acid Measurements in Saliva.

Uric acid (UA) is the most abundant antioxidant compound in saliva and one of the most sensitive biomarkers for detecting changes in the oxidative status of the organism. The aim of this study was to evaluate the effect of: (i) different methods of saliva sampling and (ii) the correction by salivary flow or total protein on UA concentrations in saliva. Paired saliva (collected by two different methods, passive drooling and using Salivette cotton rolls) and serum samples were obtained from 12 healthy men after the performance of two resistance training exercises of different level of effort that can produce different concentrations in UA in saliva. There were no significant differences between values of uric acid in saliva using Salivette and passive drool. Correlations between UA in serum and saliva and increases in UA in saliva after exercise were detected when saliva samples were obtained by passive drool and Salivette and were not corrected by salivary flow or total protein concentration. Therefore for UA measurements in saliva it would not be recommended to normalize the results by salivary flow or protein concentration. This study highlights the importance of choosing an adequate sampling method selection as well as the expression of results when analytes are measured in saliva.

Changes in lactate, ferritin, and uric acid in saliva after repeated explosive effort sequences.

The aim of the present study was to evaluate the changes in a panel of biomarkers including lactate, ferritin, and uric acid in saliva of untrained and trained subjects after repeated explosive effort sequences, and to analyze the differences in interpretation of these biomarkers depending on the way the data is expressed (without any correction or corrected by protein content or flow). Eighteen volunteers (11 untrained and 7 trained) performed 8 consecutive explosive effort sequences (60-meters sprints). Blood and saliva samples were collected before and after each sequence. Salivary data was analyzed as absolute concentration and after correcting by their protein content and flow. Lactate in saliva showed increases with acute exercise, being these increases of higher magnitude in non-trained subjects. In addition, when corrected by total protein, lactate in saliva correlates with blood lactate in non-trained subjects. Ferritin and uric acid in saliva did not show changes after the effort sequences. From the biomarkers evaluated, the measurement of lactate in saliva corrected by total protein could be useful for the assessment of fatigue induced during repeated explosive effort sequences and could be potentially used as a non-invasive alternative to blood lactate. This report also points out that way of reporting the saliva analytes could greatly influence the interpretation of the results and that lactate in saliva has a different dynamic in trained and non-trained individuals that should be further explored.

The validity, stability, and utility of measuring uric acid in saliva.

Serum uric acid (UA) is associated with many health conditions, including kidney, cardiovascular, and metabolic disorders. We examined the validity and stability of salivary UA as a noninvasive measure of serum UA. Using serum and salivary UA data from healthy adults (n=99), we examined the UA serum-saliva correlation, and UA associations with adiponectin and C-reactive protein. Using longitudinal data from young adults (n=182), we examined salivary UA stability. We found robust positive serum-saliva correlations for UA. UA and adiponectin were inversely related in serum and saliva. Salivary UA was relatively stable; 62-66% of variance could be attributed to a latent trait-like component. Salivary UA may be an important biomarker indexing health and disease risk.

A sensitive and accurate method to simultaneously measure uric acid and creatinine in human saliva by using LC-MS/MS.

To establish a method to simultaneously measure uric acid (UA) and creatinine (Cr) in human saliva. By using HPLC-MS/MS, we developed and validated a fast, sensitive and accurate method to simultaneously determine UA and Cr in human saliva. The determination range for Cr and UA is of 10-5000ng/ml with the R2 for both calibration curves over 0.999. The accuracy, precision and recovery of Cr and UA were all acceptable. By using the established method, the Cr and UA levels in saliva from 28 healthy volunteers were measured as 2.9±0.8µM and 46.8±18.2µM, respectively. This method can simultaneously determine Cr and UA in saliva for clinical and translational study.

Association between body mass index and salivary uric acid among Mexican-origin infants, youth and adults: Gender and developmental differences.

Uric acid (UA) is the end product of the metabolic breakdown of purine nucleotides. Recent studies have measured UA in saliva in relation to obesity and chronic disease risk. Given the increasing prevalence of metabolic syndrome among Latino youth, we examined gender and age differences in salivary uric acid (sUA) and weight in a sample of Mexican-origin children (n = 65, 2 months to 18 years, 49% female) and adults (n = 46, 19-58 years, 72% female). We measured weight, height, waist, and hip circumference and collected saliva samples (later assayed for sUA). Structural equation models estimated the relationship between age, developmental stage, and weight outcomes in relation to sUA levels between genders, while controlling for race. Results demonstrate that increased sUA levels were related to higher BMI percentiles in females of all ages (β = 0.43, p < .001). There were significant differences in sUA levels between developmental stages for girls, with female toddlers having the highest sUA levels (β = .28, p = .02). In an interaction between BMI z-score and gender between youth and adults, BMI has a larger effect on increasing sUA levels among younger girls (β = 0.27, p < .03) and adult women (β = 0.33, p = .02). Levels of sUA may be gender-specific in relation to BMI and developmental stage.

Uric acid concentration in saliva and its changes with the patients receiving treatment for hyperuricemia

To date, few studies have examined uric acid in saliva or dental calculus. The purpose of this study is to examine the uric acid concentration in saliva and serum. Saliva and blood samples were collected from 244 participants. We divided them into four groups: untreated or treated group in normal or abnormal serum uric acid concentration groups. Within the untreated group, Pearson’s correlation coefficient was used to examine the correlation between salivary and serum uric acid concentrations. We compared uric acid concentrations between saliva and serum, or between untreated and treated groups using the paired or unpaired student’s t-test. In the untreated group, uric acid concentrations in saliva and serum were significantly and positively correlated (r = 0.503, P < 0.01). Within the untreated group, those with abnormal serum uric acid concentrations had significantly higher uric acid concentrations in serum and saliva compared to those with normal serum uric acid concentrations (P < 0.01). Within the untreated group, uric acid concentrations in serum were significantly higher than that in saliva (P < 0.01). Uric acid concentrations in saliva of the treated group were significantly higher than that of the untreated group (P < 0.01). Within the treated group, uric acid concentrations in saliva were significantly higher than that of serum, particularly in users of benzbromarone (P < 0.01). Uric acid concentrations in saliva were lower than that in serum among non-users of benzbromarone. In contrast, uric acid concentrations in saliva of patients taking benzbromarone were higher than that in serum. We surmise that URAT1 may influence uric acid excretion in the salivary gland.

CE Determination of Creatinine and Uric Acid in Saliva and Urine During Exercise

A simple and reliable method based on capillary electrophoresis with electrochemical detection (CE–ED) was applied to study the effect of aerobic exercises on creatinine and uric acid concertration in saliva and urine. The pH value, the running buffer concentration, the SDS concentration, separation voltage, injection time and the potential applied to the working electrode were investigated to find the optimum conditions. The detection limits (S/N = 3) for creatinine and uric acid were 3.6 μmol L−1 and 0.86 μmol L−1, respectively. This method was successfully used in the rapid analysis of creatinine and uric acid in saliva samples. After aerobic exercises, creatinine concentration decreased, and uric acid concentration increased in saliva. In urine, the concentrations of creatinine and uric acid both increased after exercise.

Exhaustive Physical Exercise Effects on Nitric Oxide, Uric Acid, Antioxidant Activity and Oxidative Stress in Saliva of Elite Triathlete

Physical exercise can increase organism antioxidant defenses. However, it is not clear if the increase of antioxidant defenses is enough to avoid oxidative stress during long-duration physical exercise. PURPOSE: To determine the effects of exhaustive physical exercise on nitric oxide (NO) and uric acid (UA) production, oxidative stress (OS), and total antioxidant activity (TAA) in human saliva. METHODS: Twelve elite triathletes (men, n=7 and women, n=5; mean age; 21 + 1 yr) were studied during the Falcon-state 2006 triathlon. Saliva samples were withdrawn at three time points; 24 and 1 h before the race, and immediately after competition (IAC). Subsequent to rinsing the mouth with water, samples of stimulated whole saliva were placed in assay tubes and frozen at −5°C. Before analysis, saliva samples were centrifuged at 3,000 rpm for 10 min. The production of NO was determined by the Griess reaction, OS was determined by the FOX method, UA by enzymatic method, and the TAA by ABTS method. One-way ANO VA with repeated measures was used to examine effects of exhaustive physical exercise on dependent variables. The alpha level (p=0.05) was set a-priori and corrected by the Bonferroni technique for multiple comparisons. RESULTS: In human saliva, exhaustive physical exercise (participants average time in the race: 131 + 10 min) caused an increase in UA in comparison to 24 h (IAC: 3.53 ± 1.58 mg/dl vs. 24 h: 1.35 ± 0.68 mg/dl vs.; p< 0.05) and 1 h (1.96 ± 0.93 mg/dl; p< 0.05) prior to competition. In contrast, TAA decreased at 1 h before the race in comparison to 24 h prior to competition (1 h:1.02 ± 0.28 mMvs. 24 h: 1.42 ± 0.25 mM; p< 0.05), but TAA was higher at IAC in comparison to 24 h and 1h prior to competition (1.91 ± 0.42 mM; p< 0.05). Oxidative stress was reduced at 1 h before the race in comparison to 24 h prior to competition (1 h: 85.2 ± 13.9 μMvs. 24 h: 90.8 ± 9.4 μM; p< 0.05), and further decreased following exercise (69.8 ±11.8 μM; p< 0.05). On the other hand, NO derivative products were unchanged by this type of exercise in these athletes. CONCLUSIONS: Exhaustive physical exercise induced an increase in both saliva UA and TAA, and these results could explain the reduction of oxidative stress observed after the competition. In addition, these results might also demonstrate an anticipatory metabolic response before exercise.

Salivary uric acid at the acidic pH of the stomach is the principal defense against nitrite-derived reactive species: Sparing effects of chlorogenic acid and serum albumin

A complex antioxidant system is present in human saliva, with uric acid being the most concentrated component. Ascorbic acid, present at low concentrations in saliva, is actively secreted into the gastric lumen. We report that ascorbic acid added to human saliva at pH 2 was consumed within a few minutes, regenerating HNO 2, whereas uric acid was consumed relatively slowly in a nitrite-dependent manner. The consumption of uric acid was (i) rapid under normoxic conditions and slower at low oxygen tensions, (ii) coupled to NO release, (iii) linked to the decrease in nitrite consumption and in nitrate formation, and (iv) unaffected by the nitrosation catalyst thiocyanate. Both chlorogenic acid and bovine serum albumin, representative of a phenol- and a protein-rich meal, respectively, were able to spare uric acid, although chlorogenic acid increased, whereas bovine serum albumin inhibited, NO release. We hypothesize that the major role of uric acid in saliva at pH 2 could be to preserve the stomach from the formation of toxic nitrogen species and that low levels of uric acid, together with ascorbic acid consumption, may contribute to the high occurrence of tumors at the gastroesophageal junction and cardia. The sparing effects of dietary compounds may therefore be an important not fully appreciated effect.

Determination of uric acid in human saliva by high-performance liquid chromatography with amperometric electrochemical detection

The aim of the present study is to establish a highly sensitive method for the determination of uric acid (UA) in human saliva. The monitoring of UA levels in less invasive biological samples such as saliva is suggested for the diagnosis and therapy of gout, hyperuricemia, and the Lesch–Nyhan syndrome, and for detecting such conditions as alcohol dependence, obesity, diabetes, high cholesterol, high blood pressure, kidney disease, and heart disease. Reversed-phase high-performance liquid chromatography with electrochemical detection (HPLC–ED) was employed for the determination of UA obtained by solid-phase extraction from saliva. To quantify UA, we compared the ED efficiencies of an amperometric ED (Ampero-ED) with a single electrode and a coulometric ED (Coulo-ED) with a multiple electrode array. The results showed that the detection limits ( S/ N=3) were 3 nM for Ampero-ED and 6 nM for Coulo-ED, and the linearity of the calibration curves of 60–6000 nM had correlation coefficients exceeding 0.999. In addition, the total analytical time was 10 min. In the sample preparation of UA in saliva, an Oasis MAX solid-phase cartridge was used. The recoveries of UA spiked at 0.6 and 3 μM in saliva were above 95% with a relative standard deviation (RSD) of less than 15%. Therefore, the present method may be used in the routine and diagnostic determination of UA in human saliva.

Studies of saliva in its relation to the teeth

By the use of a slight modification of the Folin-Benedict method for the determination of uric acid in blood, we definitely established the presence of uric acid (urate) in saliva. The average quantity of uric acid in saliva from men amounted to 2.10 mg. per 100 c.c. of the secretion; in saliva from women it amounted to I. I I mg. per 100 C.C. We also succeeded in separating uric acid, in crystalline form, from saliva. For normal individuals, the proportion of uric acid in saliva was independent of the diet, speaking generally, but was influenced by the rate of secretion as well as by the nature of the stimulant employed to accelerate the flow of the saliva. Saliva appears to register promptly the variations in the endogenous metabolism of uric acid. We noted an almost immediate rise in the proportion of uric acid in saliva after increased muscular exertion, and after the ingestion of purine-free food following a brief fast. We also observed a definite relationship between the quantity of uric acid excreted in saliva, and the quantity eliminated simultaneously in the urine, in normal people on an ordinary diet. The details of this study, and those related to it, will be published in the Journal of Dental Research.