Ion Selective Electrode Method Research Articles

Ion-Selective Optodes Integrated Paper-Based Device for Simultaneous Colorimetric Quantification of Salivary Na<sup>+</sup>, K<sup>+</sup> and Ca<sup>2+</sup>

The quantification of electrolytes in biological fluids plays an important role for evaluating the human health condition. This work proposes a disposable and simple microfluidic paper-based analytical device (μPAD) for the quantitative colorimetric detection of salivary Na+, K+ and Ca2+, relying on ion-selective optodes (ISOs). Nanoscale ISOs composed of pluronic F-127 surfactant-based micelles were used as a colorimetric indicator system, reducing the assay time compared to the previously reported bulk membrane approach. Devices consist of three functionalized paper layers assembled by lamination, with the optical signal read out from the bottom layer. Saliva was chosen as the biological specimen because it is painlessly collected and easy-to-handle, which makes it suitable for POC assays. Simultaneous Na+, K+ and Ca2+ detection by a single μPAD was successfully confirmed by using aqueous metal ion samples with various concentrations of Na+, K+ and Ca2+ within the biologically relevant range. The simultaneous detection of the three cationic species enabled the correction of the three ion quantities by eliminating the interference from other ions using the calculated selectivity coefficients. For proof-of-concept, Na+ quantification in a human saliva sample was conducted by the developed μPADs. The calibration curve for this assay was prepared by applying artificial saliva to the μPADs. The concentrations of Na+ in spiked human saliva were also measured by the μPADs. The obtained recovery rates were 78-132 %, which indicates the quantification of the added Na+ in the real sample matrix. Finally, this μPAD was successfully integrated into a smartphone-based assay, which enables salivary electrolyte quantification in resource poor settings. The developed μPADs satisfy the criteria of low-cost (< $0.3/device), rapidity (< 5 min) and simple analytical procedure compared to the conventional ion-selective electrode (ISE) method.

Urinary fluoride and micronutrients intake in children from San Luis Potosi, Mexico

ABSTRACT To assess the relationship between urinary fluoride and micronutrients intake we recruited 121 schoolchildren from San Luis Potosí. We evaluated fluoride concentrations in drinking water and urine with the ion-selective electrode method and estimated calcium, magnesium, and phosphorus intakes with a validated consumption frequency questionnaire. About 72% of the population used tap water for drinking and cooking. Fluoride concentrations were 2.36 ± 0.02 mg/L in tap water, 0.14 ± 0.04 mg/L in bottled water and 2.05 ± 0.62 mg/L in urine. Urinary fluoride was higher in children with a consumption <50% of the Recommended Daily Intake (RDI) of calcium (2.20 v/s 1.96 mg/L; p < 0.05), <50% RDI of magnesium (2.58 v/s 1.96 and 1.90 mg/L; p < 0.05) and >150% RDI of phosphorus (2.43 v/s 1.82 mg/L; p < 0.05). These data indicated that fluoride concentration in tap water is higher than bottled water and estimated micronutrients intake is related to urinary fluoride.

Iodine Modifies the Susceptibility of Thyroid to Fluoride Exposure in School-age Children: a Cross-sectional Study in Yellow River Basin, Henan, China.

Excessive fluoride exposure has detrimental effects on the thyroid gland, which may be modified by iodine. However, the role of iodine in it remains unclear. This study aims to evaluate the role of iodine in thyroid abnormalities caused by fluoride exposure in school-age children. A total of 446 children aged 7-12 years were recruited from Tongxu County, Henan province, in 2017 (ZZUIRB 2017-018). We obtained demographic information through questionnaire surveys. The concentrations of urinary fluoride (UF) and urinary iodine (UI) were determined by the ion-selective electrode method and the catalytic spectrophotometric method, respectively. The radiation immunoassay was used to determine the serum concentrations of total triiodothyronine (TT3), total thyroxine (TT4), and thyroid-stimulating hormone (TSH). The B-mode ultrasound was performed to assess thyroid volumes (Tvols). The associations between fluoride exposure and thyroid-related indicators were tested by linear regression models. We found that Tvols increased by 0.22 (95% CI: 0.14, 0.31) cm3 with each standard deviation increment of UF. Moreover, Tvols in boys were more susceptible to fluoride exposure than those in girls, and the Tvols of children with high urinary iodine are less susceptible to fluoride exposure (P for interaction < 0.05). We also observed that TT3 levels were negatively related to UF concentrations at moderate urinary iodine levels (≤ 300 μg/l). Fluoride exposure can elevate the Tvols of school-age children, especially in boys, and high levels of iodine may alleviate this effect to some extent.

Optimized ion selective electrode for determination of Tamsulosin hydrochloride in the presence of co-formulated Deflazacort in bulk, tablet dosage form and human urine

Direct analytical methods offer an excellent tool for rapid determination of pharmaceuticals without deviation from the green analytical chemistry principles. In this work, a potentiometric ion selective electrode (ISE) method for the selective determination of the α1A-adrenoceptor blocker, Tamsulosin HCl was developed, optimized and assessed for greenness. Six different PVC-membrane sensors were fabricated using 2-nitrophenyl octyl ether (NPOE) as a plasticizer. Three ion exchangers were used, namely sodium tetraphenyl borate (Na.TPB), sodium tetrakis- [3,5-bis (trifluoro- methyl) phenyl] borate (Na.Tetrakis) and ammonium reineckate (Amm. RK) in exchange with the two ionophores, 4-tert-Butylcalix [8] arene (Calix.) and 2-hydroxypropyl-β-cyclodextrin (β-CD). The electrochemical responses of all sensors were studied and recorded. The sensor which consisted of sodium tetraphenyl borate as ion exchanger and 4-tert-Butylcalix [8] arene as ionophore was selected for application to analysis of Tamsulosin HCl in dosage form and human urine. The electrochemical performance characteristics of the electrode were validated as per IUPAC recommendations. Analytical Eco Scale assessment was used for evaluation of the greenness of the method and compared with the USP official method for the determination of Tamsulosin HCl.

Study of the effect of ionophore carbon chain length on the selectivity of the Nd (III) ion selective electrode

Ion selective electrode method is used for analyzing certain metal ions in a sample with ionophore as the link between two different solutions. The compounds 4-adipoybis (1-phenyl-3-methylpyrazolone-5) (H2AdBP) and 4-sebacoylbis (1-phenyl-3-methylpirazolone-5) (H2SbBP) are the same two types of ionophores but differ in the length of carbon chain. Both ionophores were used in potentiometric analysis of Nd3+ ion and showed that H2AdBP-Nd electrode had a slightly smaller detection limit, namely 1.91 x 10−5M with a sensitivity of 15.9 ± 2.2 mV/decade with a response time of 23 seconds, compared to the H2SbBP-Nd electrode with a detection limit of 2.88 x 10−5M, sensitivity of 21.9 ± 1.1 mV/decade and response time of 22 seconds. The effect of pH on the electrode performance was studied by varying the pH, concentration of ISA KNO3 and composition of the internal solution. Good electrode performance was obtained at pH 3 and the electrode sensitivity increased to pH 4. The electrode selectivity was carried out using a separate solution method (SPM) for the La3+, Ce3+ and Th4+ ions. The determination results of electrode pot showed that ESI-Nd electrode was not selective against La3+ and Ce3+ ions but selective to Th4+ with values < 1.

The use of vitreous renal chemistries in the discrimination of postmortem fresh water drowning

Background: The World Health Organization (WHO) has estimated drowning as the leading cause of unintentional death in the world, with 372,000 deaths reported annually. Not all drowning are unintentional; some could be disguised to cover up an act of heinous criminality. This study was aimed at using some vitreous renal function biochemical parameters as a discriminant of postmortem fresh water drowning. Twelve albino rabbits constituted the sample size as validated by Mead’s formula. The study was divided into three groups; the control, postmortem-drowned and truly drowned as mimicked using an artificial fresh water pond. Vitreous humours were extracted using Coe method. The vitreous renal chemistries were analysed using diacetyl monoxime, Jaffe’s test, uricase and ion-selective electrode (ISE) methods respectively. Result: The mean of vitreous creatinine, urea, uric acid, Na+, K+, Cl−, Ca2+, glucose and CO2 of the control, postmortem-drowned and truly drowned groups were compared using One-way Anova (post-hoc-LSD) with the aid of SPSS Inc., Chicago, IL, USA; Version 18–21 package. The findings revealed a significant increase in concentrations of vitreous creatinine, glucose, Ca2+ and K+ of the drowned death group, whereas vitreous concentrations of CO2 and urea significantly decreased when compared to the controls and/or postmortem-drowned death. Conclusion: The study has shown that some of the studied vitreous biochemical parameters could be used as an ancillary tool in discriminating death due to fresh water drowning from that of disguised or postmortem-drowned death.

A study comparing values of serum sodium estimated by colorimetric kit method with those obtained by direct and indirect ion selective electrode methods

Introduction: Electrolyte abnormalities are known to cause significant morbidity and mortality, when it is not detected. Dyselectrolytemias are usually treatable. Hyponatremia is a common manifestation encountered in the elderly. The rural health care facilities may not have well equipped laboratories. Therefore, this study intended to look for the possibility of establishing a screening technique that can help detect hyponatremia in such centres. Materials and Methods: Serum sodium levels were estimated in 120 samples using direct, indirect ISE and colorimeter. Statistical analysis was done using SPSS version 17, NCSS 11 and MINITAB 18 software. A p value< 0> Results: A simple linear regression analysis was done and a regression equation was derived for sodium levels while comparing between the instruments. The Bland Altman analysis gave an agreement limit of 95% between the instruments which is well within the CLIA suggested target value of ±4 mmol/L in the hyponatremic and normonatremic range. Conclusion: The derived regression equation calculates a predicted value for direct and Indirect ISE using the values obtained on the colorimeter making it comparable on all the three instruments in the hyponatremic and normonatremic ranges. The colorimetric method can be used as a cost effective screening technique to identify the hyponatremic elderly for whom a tertiary hospital may not be accessible, thus facilitating early intervention. Keywords: Serum sodium, Direct ISE, Indirect ISE, Colorimetry, Hyponatremia.

Electrolyte Concentrations and Liver Enzymes in Car Spray Painters Exposed to Car Spray Paints within Port Harcourt Metropolis, Rivers State, Nigeria

Aim: To determine the effect of car spray paint on electrolyte concentrations (sodium, potassium, bicarbonate and chloride), Anion gap, Total Protein, Albumin, liver enzymes (Alanine amino transferase and Aspartate amino transferase) of car spray painters.&#x0D; Place of Study: The study was conducted within Port Harcourt metropolis, Rivers State Nigeria.&#x0D; Methodology: Twenty (20) male car spray painters age range between 25 and 61 years with 7- 28 years work experience in car spray painting (test subjects) and twenty (20) apparently healthy male individuals aged between 25 and 61 years who work within an office setting far away from car spray painting garage (non-exposed individuals) were used as control for the study. Plasma electrolyte concentrations were estimated using Ion selective electrode method while Liver Enzymes Alanine amino transferase and Aspartate amino transferase were estimated using spectrophotometric method. Results obtained from the experiment were expressed as Mean ± Standard Deviation. P &lt; .05 were considered statistically significant.&#x0D; Results: Sodium, Potassium, Bicarbonate and Chloride concentrations in plasma of car spray painters when compared to non-car spray painters did not showed any significant difference (P&gt; .05). However, Anion gap was significantly increased (P&lt;.05) in plasma of car spray painters when compared to non-car spray painters. Alanine amino transferase activity were significantly higher in plasma of Car spray painters (P &lt; .05) when compared to non-car spray painters while Aspartate amino transferase activity, Total protein and Albumin concentrations remained relatively unchanged when compared between the studied groups. However, Aspartate amino transferase and Alanine amino transferase activities were affected by years of exposure to car paints.&#x0D; Conclusions: This study suggest that car spray paint affects Anion gap and Alanine amino transferase activity in car spray painters hence safety apparatus should be worn while working. However further test on other liver enzymes should be done to validate the effect of spray paint on the liver.

Endemic fluorosis among 14-Year-old Yemeni adolescents: an exploratory survey

To assess the extent of fluorosis in a representative sample of 14-year-old Yemeni adolescents. A random sample of 2400 14-year-old Yemeni adolescents, equally distributed by gender, zone and locations, participated in the study. Fluorosis was identified using photographs for measuring Dean's Fluorosis Index. Water samples were taken and analysed for fluoride concentration using the ion selective electrode method at the Oral Biology laboratory, University of Malaya. Fluorosis was found to be present in 30.8% of all subjects examined. Slightly more males (32.3%) than females (29.3%) were observed to have varying degrees of fluorosis. There were more cases with fluorosis among children in rural areas (31.9%) than urban children (29.7%). Adolescents in the south (46.9%) or east (49%) Yemen were found to have almost two times or more children with fluorosis than all other zones (North 15.2%, Central 20%, West 22.9%), the differences were significant at p = 0.0001. Fluoride concentration in natural drinking water in the study locations was found to be between 0.5-3.8 ppmF. Findings found fluorosis to be significant among Yemeni adolescents.

Frequency of Dental Fluorosis in Population Drinking Water with High Fluoride Level in Thar

OBJECTIVE: The objective of this study is to see the frequency of dental fluorosis in exposed area (Sammo Rind village of Thar District) and in unexposed area of Gadap town of Karachi and to find the association of fluoride level with dental fluorosis in both groups. METHODOLOGY: The water samples were taken from both the sites and fluoride estimation in water and geometrical, was determined using Fluoride Ion Selective Electrode (FISE) method. By random selection 121 subjects from Sammo Rind village and 121 controls from Gadap Town Karachi were included in study after informed consent. The participants were clinically examined by an expert university teacher dentist in proper dental setups in examination lights. RESULTS: A frequency of dental fluorosis of 100% was found among the study subjects with fluoride content as high as 6- 8 mg/dl as compared to prevalence of dental fluorosis 17.4% in unexposed group with water fluoride content as low as 0.30mg/dl. CONCLUSIONS: The high level of underground water fluoride level and cent per cent dental fluorosis in Thar area is an alarming situation that should be addressed immediately at national level. KEYWORDS: Exposed area, Dental Flurosis, Fluoride Level, Water Sample HOW TO CITE: Ahmed I, Ali A, Zaheer M, Fatima I, Khan N. Frequency of dental fluorosis in population drinking water with high fluoride level in Thar. J Pak Dent Assoc 2020;29(4):259-263. DOI: https://doi.org/10.25301/JPDA.294.259

Monitoring of fluoride in the public water supply using electrometric or colorimetric analyses

The surveillance of the concentration of fluoride in the public water supply aims to ensure the balance between the benefits (carie prevention) and risk (dental fluorosis) of water fluoridation programs. The aim of this study was to check the accuracy of two analytical methods for monitoring the concentration of fluoride in the public water supply of a Brazilian city. The STROBE checklist was used to aid the conduction of this study and report the results. It was an analytical, observational, and prospective study using the water supply of Uberlândia, MG, Brazil. We collected 126 water samples at 21 sites for six consecutive months and analyzed them using the fluoride ion selective electrode (F-ISE) method and colorimetry with SPADNS. The statistical analysis was performed descriptively and then the ANOVA and Student t-test for paired samples were applied. The results showed that the F-ISE method had a lower coefficient of variation (12.3%) than the SPADNS method (57.4%). There was no significant variation of the fluoride concentration in the water through the supply network evaluated either by F-ISE as SPADNS. We concluded that the electrometric method should be the first choice for use by laboratories that monitor fluoride concentration in the public supply water.

Myogenin level tends to decrease in adult male cigarette smokers

BackgroundThe World Health Organization has warned that cigarette smoking is an avoidable risk factor for endothelial injury. Myogenin might play a role in muscle metabolism and energy utilization. Electrolytes and minerals are involved in most cellular activities. The objective of this study was to compare myogenin and electrolyte levels between adult male cigarette smokers (CS) and non-smokers (NS). MethodsA cross-sectional study was conducted involving 90 subjects, consisting of 55 CS and 35 NS. The sandwich enzyme-linked immunosorbent assay was used to determine myogenin levels while the ion-selective electrode method was used to determine electrolyte levels. The levels of sodium, potassium, and chloride and the body mass index (BMI) were measured. Mann-Whitney and independent t-test were used to analyse the data. Results The BMI of CS was significantly lower than that of NS (p &lt; 0.05). The mean serum levels of sodium (145.23 ± 1.87), potassium (4.00 ± 0.31) and chloride (103.95 ± 1.60) were significantly higher in the CS than in the NS (these being 142.38 ± 2.49, 3.83 ± 0.33, and 101.48 ± 2.08, respectively) (p&lt;0.05). Myogenin levels (44.24 ± 14.60 pg/mL) tended to decrease in the CS group compared to the NS group (59.66 ± 61.73 pg/mL), but the difference was statistically not significant (p=0.769).Conclusion The study demonstrated that higher concentrations of sodium, potassium and chloride with lower concentrations of myogenin in smokers may be associated with higher risk of skeletal muscle tissue injury probably due to the inability of the affected small blood vessels to transport electrolytes to tissues.

Human health risk assessment and spatial distribution of fluoride from shallow groundwater in a region of southwest China

Abstract This article took fluoride in shallow groundwater of a township in southwestern China as the research object. Fifty sampling points were set up in the studied area. The fluoride was tested by the ion-selective electrode method. The health risk model recommended by the United States Environmental Protection Agency was used. Based on the Chinese population, human health risk assessment was performed for fluoride in shallow groundwater in the studied area, and the Kriging interpolation method was used to simulate the spatial distribution of fluoride concentration in the area. The research showed the following. (1) The concentration of fluoride in the shallow groundwater samples in the studied area was 0.06–0.78 mg/L, with an average value of 0.35 mg/L, which was in line with the limit value (1.00 mg/L) in the standards for drinking water quality (GB 5749–2006), but its maximum value was 0.78 mg/L, which was 1.86 times of the background value. (2) The average hazard index of children and adults were 0.27 and 0.15, respectively, which were less than 1, and the risk was at an acceptable level; the noncarcinogenic risk of children was 1.8 times that of adults; the average values of total risk quotient for groundwater fluoride intake by children and adults were 0.27 and 0.15, respectively, and 1.19E-03 and 7.26E-04 by skin, respectively. This indicated that of the two routes, oral intake was the main route of exposure to fluoride. The noncarcinogenic risk values of fluoride in rural and urban areas were similar, and both were less than 1. (3) The high-value areas of fluoride were mainly concentrated in the southeast of the area, which was mainly affected by the superposition of natural factors and industrial park sewage discharge. Through human health risk assessment and spatial distribution of fluoride in regional groundwater, it can provide a theoretical basis for regional groundwater pollution prevention.

Mechanical Properties and Fluoride Release of Glass Ionomer Cement with Enhanced Antimicrobial Activity Derived from Addition of Schiff Base of Tetronic 1107

Abstract: Objectives: To synthesize and characterize Schiff base of Tetronic 1107 (T1107SB) to be added to GIC powder to enhance its antimicrobial activities and to evaluate the compressive strength (CS), elastic modulus (E), Vickers microhardness (HV) and fluoride release (FR) of the synthesized GIC. Materials and methods: T1107SB was synthesized by chloroacetylation of T1107, amination of chloroacetylated T1107 and modification of aminated T1107 with vanillin. Characterization of T1107SB was carried out by Fourier transform infra-red spectroscopy (FTIR), Elemental micro-analysis and Thermal gravimetric analysis (TGA). Antimicrobial activity of T1107SB-modified GIC (T-GIC) was studied by the cut plug method and minimal inhibitory concentration (MIC) test. CS and E were investigated in a universal testing machine according to the ISO 9917:2007. HV was evaluated by a Digital Microhardness Tester. Fluoride levels in ppm were obtained using the ion-selective electrode method. A one-way ANOVA and Bonferroni test were used to analyze the data (p ≤ 0.05). Results: Synthesis of T1107SB was confirmed by FTIR, elemental micro-analysis and TGA. T-GICs exhibited an enhanced antibacterial activity against Staphylococcus aureus and Bacillus cereus as confirmed by the growth inhibition zones. T-GICs showed no improvement in the antimicrobial activity against Candida albicans, compared to C-GIC. Significant differences were found between studied groups in CS, E, HV and FR. Increasing the percent of T1107SB resulted in a systematic reduction these properties. Conclusions: Addition of T1107SB is promising in enhancing the antibacterial activity of GIC materials without deteriorating their mechanical and fluoride-releasing properties.

Adsorption of Fluoride from Aqueous Solution and Groundwater onto Activated Carbon of Avocado Seeds

In the East African Rift Valley, groundwater is severely polluted with fluoride ion which causes a scarcity of water supplies and public health problems. This study is aimed at investigating the adsorption performance of activated carbon of avocado seeds (ACAS) in fluoride removal from aqueous solution and groundwater. The batch adsorption experiments were carried out by varying the contact time, solution pH, agitation speed, adsorbent dose, and initial fluoride concentration at constant room temperature using the fluoride ion–selective electrode method. Adsorption of fluoride onto ACAS reached its equilibrium condition at the contact time of 60 min under the stirring rate of 200 rpm, pH 6, and ACAS dose 1.9 g/100 mL with an initial fluoride concentration of 5.2 mg/L. Maximum adsorption efficiency was found to be 86%, whereas the fluoride removal from groundwater was 72% under the same experimental condition. The experimental data were well fitted with the Langmuir model with a maximum adsorption capacity of 1.2 mg/g, whereas the kinetic model was well described by a pseudo-second-order model at R2 0.99. Generally, the research findings showed that activated carbon can be employed as an alternative adsorbent for fluoride remediation from domestic water supplies.

Prevalence of dental and skeletal fluorosis in relation with the fluoride levels in drinking water among the primary school children at Laxmisagar Grampanchayat of Bankura District, West Bengal India

To estimate the prevalence of dental and skeletal fluorosis in relation with different fluoride levels in drinking water among school going children aged 6-12 years. The cross sectional study was conducted in the six primary schools of Lakshmisagar Grampanchayat, Bankura District, West Bengal, India. Dental fluorosis was recorded using Dean's index. The drinking water samples were collected in polyethylene bottles and the fluoride content of these samples was determined by fluoride ion selective electrode method using Orion microprocessor analyser. The overall prevalence of dental and skeletal fluorosis among the school students of this study area was 78.47% and 13.87% respectively. The study noted that the maximum fluoride level in the drinking water of the six schools were 9.15, 3.46, 3.46, 3.46, 3.28, and 2.11 ppm respectively though the prevalence of dental fluorosis was noted among the students of this region were 100.00%, 76.92%, 78.85%, 42.86%, 91.30% and 94.74% respectively. This study found that the fluorosis level in drinking water was not the single most factors for determining the fluorosis but there might be some other factors associated with causation of fluorosis and these factors also modulate the severity of the fluorosis. Nutrition is the most important factors to reduce the fluoride level from the human body. Keywords: Fluorosis, Fluoride, Bankura district, Prevalence.

Rapid determination of trace potassium in drinks and serum by Rayleigh light scattering technique

In this paper, a sensitive, rapid and selective method based on Rayleigh light scattering technique (RLS) was proposed for the determination of potassium using a conventional spectrofluorometer. Potassium was transformed to KB(C6H5)4 particles, which displayed intense light scattering in aqueous solutions. Effects of factors such as wavelength, acidity, ionic strength and coexistent interferents on the RLS of B(C6H5)4-K were investigated. The RLS intensity of the KB(C6H5)4 suspension was obtained in NaAc solution (0.50 M, pH = 8.0) and the addition of 0.5 mL of sodium dodecyl benzene sulfonate (5.05 μM) and 1.0 mL of tetraphenylborion sodium (1.0%). The Rayleigh scattering light intensity at the maximum peak of 567 nm was proportional to the concentration of potassium ion in the range of 0.20-1.60 μg mL-1 with a detection limit of 0.10 μg mL-1. To determine the feasibility of the proposed method, samples of water, drinks and serum were analyzed. The attained results were in agreement with the ion-selective electrode method. Good recovery was also obtained in a range of 95.10-107.02%. The sensitivity and selectivity of the RLS method are high enough to determine trace amounts of potassium ion without any significant interference from high levels of other components such as common anions and cations.

Determination of fluoride in tea leaves and tea infusions by ion selective electrode

A fluoride ion selective electrode method for the determination of fluoride contents in tea leaves and tea infusions was set up. Using commercial timothy grass powder and tea leaf powder as standard materials, this method demonstrated linearity between 0.02 and 2.00 mg/L of fluoride with R2 greater than 0.999. Both materials had coefficient of variations (CV, %) less than 3%, indicating good reproducibility in the determinations. The recovery tests of tea infusions spiked with different amounts of sodium fluoride demonstrated 94-107% of recovery with CV less than 1.2%, indicating that the method is very accurate. With 1% of tea leaves to boiling water ratio, up to 63-78% of fluoride in tea leaves could be released into tea infusion by repeated infusions and 82-83% by continuous infusion. By this method, total fluoride contents of 12 brands of tea leaves purchased from Nantou County were determined to be 100-451 mg/kg dry weight, and those of their infusions in boiling water for a 5-min period were determined to be 0.39-1.21 mg/L. Assuming that daily tea infusions drinking for an adult is 2 L, fluoride intake from tea infusions of these tea leaves is far below the daily fluoride tolerable upper limit 10 mg.

SKlotho is associated with the severity of brick tea-type skeletal fluorosis in China

The change of serum soluble Klotho (sKlotho) content is related to a variety of osteoarthropathy. However, its association with the severity of skeletal fluorosis (SF) is not clear. Here, the association of tea fluoride exposure with serum sKlotho levels and the severity of SF were investigated and further verified in a rat model of fluorosis. A cross sectional case control study was conducted in residents over 50 years old from brick-tea drinking areas in Qinghai and Xinjiang Provinces, China. Concentrations of fluoride in brick tea water and urine were determined by ion selective electrode method, and the levels of serum sKlotho were determined by ELISA method. Linear regression and ordered logistic regression models were constructed to examine the relationship among fluoride exposure, serum sKlotho levels and the severity of SF. The kidney and small intestine of Wistar rats were isolated for detection of Klotho by immunohistochemistry (IHC), and femoral artery blood was sampled to measure the serum levels of sKlotho. An increase of 1 mg/day in tea fluoride intake (TFI) was associated with a 12.070 pg/mL (95% CI: 0.452–23.689) increase in serum sKlotho levels and a 1.163-fold (95% CI: 1.007–1.342) increase in the severity of SF after adjusting for age, gender, and ethnicity. Serum sKlotho levels were also positively associated with the severity of SF (P < 0.05). The mediation analysis showed that serum sKlotho levels mediated 17.76% of the increase in the severity of SF caused by an increase of 1 mg/day of TFI. Moreover, a significant increase of serum sKlotho levels in fluoride-exposed groups was also seen in the rat model. The present study suggests that serum sKlotho may be a potential mediator of SF in brick tea-type fluorosis endemic areas.

Correlation Between Spot Urine Sodium, 24 Hour Urinary Sodium and Food Frequency Questionnairein Estimation of Salt Intake in Healthy Individuals

Background:Salt intake is a known contributor to increased blood pressure. However, it is rarely monitored in clinical practice. 24-hr urinary sodium (24-HrNa) is the gold standard method to estimate salt intake but this method is rather burdensome.Objective: The objective of this study is to correlate between spot urine sodium (SUNa), 24-HrNa and Na intake estimation by food frequency questionnaire (FFQ) (FFQNa).Methods : 430 healthy participants aged between 20-40 years old were recruited. Second morning voided urine samples were obtained from all participants to estimate SUNa. 24-HrNa samples were obtained from 77 out of 430 participants. All participants were required to answer a validated FFQ. Urine samples were analysed for Na using indirect ion-selective electrode (ISE) method. Daily sodium intake was calculated from the FFQ.Results:The mean daily sodium intake from 24-hrNa (n=77) was 155 mmol/day, SUNa (n=430) was 158 mmol/L and FFQNa (n=430) was 271 mmol/day. There was a moderate correlation between SUNa and 24-hrNa (ρ = 0.62, P &lt; 0.000). No correlation was seen between both 24-hrNa and SUNa with FFQNa (ρ = 0.035, P = 0.768 and ρ = 0.026, P = 0.597 respectively).Conclusion: Spot urine Na is a simple cost-effective method to estimate daily Na intake and has the potential to replace 24-hour urinary Na.International Journal of Human and Health Sciences Vol. 05 No. 01 January’21 Page: 74-80