OBJECTIVES: The aims of this study were to determine the total fluoride concentration and bioavailable fluoride concentration in different toothpastes, based on a newly suggested method by the International Organization for Standardization (ISO), and to compare the measured concentrations with the concentrations written on the packaging. METHODS: The concentrations of total fluoride (TF) and bioavailable fluoride (BF) were measured in six toothpastes. For the TF measurement, 1 g of each toothpaste was mixed with dipotassium hydrogen phosphate (K2HPO4), and hydrogen chloride (HCl) was placed. After 24 hours, the samples were centrifuged and total ionic strength adjustment buffer (TISAB) solution was added. For the BF measurement, the toothpaste was mixed with K2HPO4 for only 1 minute. The samples were centrifuged, and then HCl was placed and allowed to stand for 24 hours. The TISAB solution was added subsequently. The concentration of fluoride ions was measured using a fluoride ion-selective electrode and calculated against a standard curve. RESULTS: The six toothpastes were composed of different fluoride compounds and abrasives. The measured TF concentration ranged from 624.99 ppm to 1,353.00 ppm, and the similarity to the declared fluoride concentration ranged from 53.48% to 93.31%. The measured BF concentration ranged from 587.61 ppm to 1,360.05 ppm, and the similarity to the expected fluoride concentration ranged from 41.97% to 93.80%. Two samples were clearly separated when the samples were centrifuged, whereas the remaining four samples had unclear supernatants. The clearly separated toothpastes (i.e., toothpastes 5 and 6) had BF concentrations that were similar to or lower than the declared fluoride concentrations and the measured TF concentrations. However, the unclearly separated toothpastes showed inconsistent relationships between the measured TF and BF concentrations. CONCLUSIONS: The measured TF and BF concentrations of the six toothpastes did not reach the expected fluoride concentration. This finding resulted from the different compositions and forms of the toothpastes. Therefore, the properties of toothpastes need to be considered when measuring their fluoride concentrations.
Biological Availability* ; Fluorides* ; Hydrochloric Acid ; Hydrogen ; Ion-Selective Electrodes ; Ions ; Osmolar Concentration ; Product Packaging ; Toothpastes*

BACKGROUND: Analyzing large numbers of specimens in a short time and generating accurate results while minimizing costs are critical to laboratory tests. The CS-6400 (Dong-A Dirui, China), an automated chemistry analyzer, has been recently developed in China in collaboration with domestic corporations. To assess the performance and usability of the analyzer, we evaluated its analytical performance and clinical usefulness including accuracy and linearity of electrolytes and chemistry tests using HiSens reagent (HBI Co., Korea) with protocols provided by the Clinical and Laboratory Standards Institute, and compared these results with those of the formerly used DXC800 (Beckman Coulter, USA), and Vista500 (Siemens, Germany). METHODS: The accuracy, linearity, recovery factor, and sample carryover of the CS-6400 using HiSens reagent were determined for 29 tests-aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma glutamyl transferase, glucose, total cholesterol, triglyceride (TG), amylase, lipase, creatine kinase (CK), blood urea nitrogen, creatinine, uric acid, total protein, albumin, total bilirubin (TB), direct bilirubin (DB), calcium, inorganic phosphorus, magnesium (MG), HDL cholesterol, rheumatoid factor (RF), LDL cholesterol, C-reactive protein, anti-streptolysin O, sodium, potassium, and chloride and the results were compared with the values obtained from the DXC800 and Vista500 to set reference intervals for each test. Serum samples obtained from 128 healthy adults were used for the reference intervals. and values obtained from DXC800 and Vista500 were used to make comparison on and to set reference intervals for each routine. Serum specimens obtained from a total of 128 healthy adults were used for the reference intervals. RESULTS: The coefficient of variation showed excellent values of < or =5% for all tests except ALP, DB, MG, RF, TB, and TG (> or =5%). The coefficient of determination (R2) was > or =0.993 with linearity between 0.928 and 1.078 within the useful clinical span. In addition, the recovery factor values of the tests were 84% to 108%, and correlation comparisons were 0.975 except for albumin (0.9516), RF (0.7617), and LDL cholesterol (0.9709). We evaluated whether the CS-6400 contributed to the attempt to minimize the test's cost and running time. Developed in China, the CS-6400 has been approved by the Food and Drug Administration and uses indirect ion selective electrodes for electrolytes and colorimetry and turbidimetry for general and specific chemistry items. The tests showed excellent linearity of > or =0.993 using commercial certified linearity material. The recovery factor values of the tests were 93% to 108%, except for LDL cholesterol (84%). Except for the minimum values, percentage sample carryover values for CK and LDH were < or =1% (0.00% and 0.07%, respectively), suggesting that the results of the tests were not affected by sample carryover, and reference interval was present based on sex. CONCLUSIONS: The CS-6400 with HiSens showed excellent analytical performance (precision, linearity, and accuracy). Furthermore, results from the CS-6400 were highly correlated with those obtained from similar tests performed on DXC800 and Vista500. Therefore, the CS-6400 is appropriate for tertiary care hospitals where large volumes of test samples must be processed within a short period with minimal cost.
Adult ; Alanine Transaminase ; Alkaline Phosphatase ; Amylases ; Bilirubin ; Blood Urea Nitrogen ; C-Reactive Protein ; Calcium ; China ; Cholesterol ; Cholesterol, HDL ; Cholesterol, LDL ; Colorimetry ; Cooperative Behavior ; Creatine Kinase ; Creatinine ; Electrolytes ; Glucose ; Humans ; Ion-Selective Electrodes ; L-Lactate Dehydrogenase ; Lipase ; Magnesium ; Nephelometry and Turbidimetry ; Phosphorus ; Potassium ; Rheumatoid Factor ; Running ; Sodium ; Tertiary Healthcare ; Transferases ; United States Food and Drug Administration ; Uric Acid

OBJECTIVETo evaluate the uncertainty of measurement result of urinary fluoride and to provide quality assurance for determinations.

METHODThe investigation was conducted, according with principles and methods for uncertainty evaluation.

RESULTSThe uncertainty of the combined standard of present method was 2.86 %. For the sample containing 4.47 mg/L urinary fluoride, the expanded uncertainty was 0.26 mg/L.

CONCLUSIONThe uncertainty of the present method was mainly from the sample repeatability, the preparation of standard solution, the linearity of the calibration curve and instruments and so on.

Air ; analysis ; Hydrobromic Acid ; analysis ; Ion-Selective Electrodes ; Workplace

The anion gap in the serum is useful in the interpretation of acid-base disorders and in the diagnosis of other conditions. In the early 1980s, ion-selective electrodes for specific ionic species were introduced for the measurement of serum electrolytes. This new method has caused a shift of the anion gap from 12+/-4 mEq/L down 6+/-3 mEq/L. It is worthy for clinicians to understand the range of normal anion gap and the measuring methods for serum sodium and chloride in the laboratories that support their practice. While an increase in the anion gap is almost always caused by retained unmeasured anions, a decrease in the anion gap can be generated by multiple mechanisms.
Acid-Base Equilibrium* ; Anions ; Diagnosis ; Electrolytes ; Ion-Selective Electrodes ; Sodium

A change in pH can alter the intracellular concentration of electrolytes such as intracellular Ca2+ and Na+ ([Na+]i) that are important for the cardiac function. For the determination of the role of pH in the cardiac magnesium homeostasis, the intracellular Mg2+ concentration ([Mg2+]i), membrane potential and contraction in the papillary muscle of guinea pigs using ion-selective electrodes changing extracellular pH ([pH]o) or intracellular pH ([pH]i) were measured in this study. A high CO2-induced low [pH]o causes a significant increase in the [Mg2+]i and [Na+]i, which was accompanied by a decrease in the membrane potential and twitch force. The high [pH]o had the opposite effect. These effects were reversible in both the beating and quiescent muscles. The low [pH]o-induced increase in [Mg2+]i occurred in the absence of [Mg2+]o. The [Mg2+]i was increased by the low [pH]i induced by propionate. The [Mg2+]i was increased by the low [pH]i induced by NH4Cl-prepulse and decreased by the recovery of [pH]i induced by the removal of NH4Cl. These results suggest that the pH can modulate [Mg2+]i with a reverse relationship in heart, probably by affecting the intracellular Mg2+ homeostasis, but not by Mg2+ transport across the sarcolemma.
Animals ; Cations, Divalent ; Female ; Guinea Pigs ; Heart Ventricles/metabolism ; Hydrogen-Ion Concentration ; Ion Transport/physiology ; Ion-Selective Electrodes/veterinary ; Magnesium/*metabolism ; Male ; Membrane Potentials/physiology ; Papillary Muscles/*metabolism ; Propionates/pharmacology ; Sodium/*metabolism

BACKGROUND: Direct measurements of ionized magnesium (iMg) in serum by ion-selective electrodes have recently become available in clinical practice, and its usefulness needs to be investigated in dialysis patients because chronic renal failure is associated with disturbances in magnesium metabolism. METHODS: We measured serum iMg in 29 hemodialysis (HD) patients and 24 peritoneal dialysis (CAPD) patients using an ion-selective electrode. The results were compared with those from 30 age- matched control patients who were admitted due to non-renal diseases and were confirmed to have normal serum total magnesium (tMg) levels. RESULTS: Serum tMg was significantly higher in both HD (0.95 [0.81-1.06] mmol/L) and CAPD (0.86 [0.74-0.99] mmol/L) patients compared with the controls (0.74 [0.70-0.78] mmol/L). Serum iMg was significantly higher in HD patients (0.65 [0.60-0.72] mmol/L) compared with the controls (0.55 [0.51-0.57] mmol/L), but was not higher in CAPD patients (0.54 [0.50-0.60] mmol/L). Thus, the ionized fraction of serum magnesium (iMg/tMg) was significantly lower in CAPD patients (65.3 [58.8-68.2]%), but not in HD patients (68.7 [63.6-77.0]%), compared with the controls (72.2 [67.2-78.3]%). In dialysis patients, iMg/ tMg was significantly lower in those with residual renal function than in anuric patients (67.5 [63.6-74.8]% vs. 61.4 [56.4-70.7]%). CONCLUSION: In current practice, true hypermagnesemia may exist frequently in HD patients (at predialysis), but not in CAPD patients. The ionized fraction of serum magnesium may be reduced in CAPD patients, but not in HD patients.
Dialysis* ; Humans ; Ion-Selective Electrodes ; Kidney Failure, Chronic ; Magnesium* ; Metabolism ; Peritoneal Dialysis ; Peritoneal Dialysis, Continuous Ambulatory ; Renal Dialysis

OBJECTIVE: Traumatic brain injury has been shown to result in a decrease of the brain-free magnesium concentration that is associated with the development of neurologic deficits. However, changes in free magnesium homeostasis have not been characterized in other fluid compartments. We examine the ionized serum magnesium(Mg2+) and ionized serum calcium(Ca2+) in the moderate diffuse axonal injury of rat model. METHODS: We designed a study to determine whether ionized serum magnesium(Mg2+) and / or ionized serum calcium(Ca2+) levels correlate with moderate diffuse axonal injury(mDAI). A new ion-selective electrode was used to determine Mg2+ and Ca2+ level in the serum, prior to and following weight-drop induced mDAI. RESULTS: Serum Mg2+ remained significantly depressed to about 76% of preinjury values for 3 hours (0.73+/-0.01 mg/dL, 0.79+/-0.03 mg/dL, 0.84+/-0.03 mg/dL at 1, 2, 3 hours after trauma, respectively) compared to control group (1.07+/-0.03 mg/dL, p<0.05), but not in total serum magnesium(tMg). Mg2+/ tMg was shown a significant decrease for first 3 hours (49%, 53.4%, 56.4% at 1, 2, 3 hours after trauma respectively) compared to control group (70.9%, p<0.05). Head trauma resulted in small decrease of Ca2+, but there was a significant increase in the amount of Ca2+/ Mg2+(mean value in control group: in injured group for 3 hours after trauma = 4.65+/-0.012: 5.71+/-0.015, p<0.05). Apoptotic change was shown at 3 hours after mDAI and apoptotic index(AI) was significantly increased at 12 and 24 hours after trauma (54.8+/-1.7, 51.5+/-3.2 at 12, 24 hours, p<0.05). CONCLUSION: These findings suggest that the early decline in serum Mg2+ and increase in the amount of Ca2+/ Mg2+ following brain trauma may be a critical factor in the development of irreVersible tissue injury and early treatment with magnesium salt may be effective in histological changes following experimental traumatic brain injury in the rat.
Animals ; Apoptosis ; Axons ; Brain Injuries ; Calcium* ; Craniocerebral Trauma ; Diffuse Axonal Injury* ; Homeostasis ; Ion-Selective Electrodes ; Ions* ; Magnesium* ; Models, Animal ; Neurologic Manifestations ; Rats*

Animals ; Boron ; analysis ; urine ; Ion-Selective Electrodes ; Minerals ; chemistry ; Urine ; chemistry

To develop optimal shift systems for an improvement of work schedule satisfaction, health and work productivity, the effects of the direction of the rotational work shifting on the circadian rhythm and adaptation of physiological components and work mistakes were investigated in nursing students. Two groups of seven volunteers participated as experimental subjects, apd seven to twenty nursing students participated as a control group. The directions of rotation work shift were as follows CW(clockwise)-shift system rotation in the direction of day shift(3 days), evening shift(3 days), off duty(l day) and night shift(5 days), and CCW (counterclockwise) -shift system rotation in the reverse direction. Urinary Na, K, and Cl levels were measured with ion-selective electrodes. The levels of performance were measured by a questionnaire to determine the number of mistakes in 12 specific items during duty. The disturbance of Na the circadian rhythm was seen on day and night shifts, especially in the CCW-rotation shift system, and the magnitude of the daily variation was greatest in the CCW-rotation system. The daily rhythms of K and Cl shifted to the right on the evening shift, and the rhythms were reversed on the night shift, which suggests that they adapted to the altered shift work. However, the levels of Cl were higher in day and night shift workers, especially in CCW-shift system. In the ease of urine salts, it seems that the students in CW-shift system more easily adapted to the altered shift. The incidence of mistakes during work were more frequent on the CCW shift than in the CW shift. These data indicate that the direction of rotation effects the worker's health and work performance. These results indicate that the CCW rotation of shift work makes it more difficult for the workers to adapt to the shift on a physiological level, and has many more negative effects on the shift workers' health when compared with the CW rotation. Thus, a clockwise rotating shift system seems to be more desirable for the optimal health and performance of nurses.
Appointments and Schedules ; Circadian Rhythm* ; Efficiency ; Humans ; Incidence ; Ion-Selective Electrodes ; Salts ; Students, Nursing ; Volunteers ; Surveys and Questionnaires