Natural history of asymptomatic gallbladder stones in clinic without beds: A long-term prognosis over 10 years.

BACKGROUND: Several studies have explored the long-term prognosis of patients with asymptomatic gallbladder stones. These reports were primarily conducted in facilities equipped with beds for addressing symptomatic cases. AIM: To report the long-term prognosis of patients with asymptomatic gallbladder stones in clinics without bed facilities. METHODS: We investigated the prognoses of 237 patients diagnosed with asymptomatic gallbladder stones in clinics without beds between March 2010 and October 2022. When symptoms developed, patients were transferred to hospitals where appropriate treatment was possible. We investigated the asymptomatic and survival periods during the follow-up. RESULTS: Among the 237 patients, 214 (90.3%) remained asymptomatic, with a mean asymptomatic period of 3898.9279 ± 46.871 d (50-4111 d, 10.7 years on average). Biliary complications developed in 23 patients (9.7%), with a mean survival period of 4010.0285 ± 31.2788 d (53-4112 d, 10.9 years on average). No patient died of biliary complications. CONCLUSION: The long-term prognosis of asymptomatic gallbladder stones in clinics without beds was favorable. When the condition became symptomatic, the patients were transferred to hospitals with beds that could address it; thus, no deaths related to biliary complications were reported. This finding suggests that follow-up care in clinics without beds is possible.

Determination of Albumin, Glucose, and Creatinine Employing a Single Sequential Injection Lab-at-Valve with Mono-Segmented Flow System Enabling In-Line Dilution, In-Line Single-Standard Calibration, and In-Line Standard Addition.

A mono-segmented sequential injection lab-at-valve (SI-LAV) system for the determination of albumin, glucose, and creatinine, three key biomarkers in diabetes screening and diagnosis, was developed as a single system for multi-analyte analysis. The mono-segmentation technique was employed for in-line dilution, in-line single-standard calibration, and in-line standard addition. This made adjustments to the sample preparation step easy unlike the batch-wise method. The results showed that the system could be used for both fast reaction (albumin) and slow reaction (glucose with enzymatic reaction and creatinine). In the case of slow reaction, the analysis time could be shortened by using the reaction rate obtained with the SI-LAV system. This proposed system is for cost-effective and downscaling analysis, which would be applicable for small hospitals and clinics in remote places with a small number of samples but relatively fast screening would be needed.

Progress in a selective method for the determination of the acetaldehyde-derived DNA adducts by using HILIC-ESI-MS/MS.

Acetaldehyde (AA), which is present in tobacco smoke, automobile exhaust gases and alcohol beverage, is a mutagen and carcinogen. AA reacts with 2'-deoxyguanosine (dG) in DNA to form N2-ethyl-dG (EtdG) and cyclic, 1, N2-propano-dG (CPrdG), which are considered to have a critical role in carcinogenesis induced by AA. In this study, we have developed a highly sensitive method for the quantitation of the two AA-derived DNA adducts by using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in which hydrophilic interaction chromatography (HILIC) employing mobile phases of high organic solvent concentration was selected to improve the ionization efficiency in the ESI process. Fourteen times and 11 times larger peak areas for EtdG and CPrdG, respectively, in HILIC-ESI-MS/MS were obtained compared with those in reversed phase (RP)-LC-ESI-MS/MS. Furthermore, 6.9 times (for EtdG) and 2.4 times (for CPrdG) larger peak areas were also obtained as additional enhancement by varying additive compounds in the HILIC mobile phases from ammonium acetate to ammonium bicarbonate. In total, the enhancements in detected MS signal intensities by exchanging from the RP-LC system to the HILIC system are 97 times for EtdG and 26 times for CPrdG, respectively. Three commercially available HILIC columns with different polar functional groups were examined and sufficient separation between normal 2'-deoxynucleosides and the AA-derived DNA adducts was achieved by a carbamoyl-bonded HILIC column. Finally, we applied the established method to quantify EtdG and CPrdG in the damaged calf thymus DNA.

Advanced Stopped-in-Loop Flow Analysis with a Reagents-Merging Zones Technique for a Catalytic Successive Determination of Vanadium and Iron.

An advanced stopped-in-loop flow analysis (SILFA) is proposed for the catalytic determinations of vanadium and iron. The chemistry relies on a vanadium- or iron-catalyzed oxidative reaction of p-anisidine by bromate or hydrogen peroxide in the presence of an activator (Tiron or 1,10-phenanthlorine) to form a red dye (510 nm). Reagents for the vanadium- or iron-catalyzed reaction are well mixed by a reagents-merging zones technique. A sample solution is loaded together with well-mixed reagents into a loop in the SILFA configuration, followed by spectrophotometric detection. The advanced SILFA system provides a selective method for the trace determination of vanadium and iron.

Stopped-in-loop flow analysis system for successive determination of trace vanadium and iron in drinking water using their catalytic reactions.

An automated stopped-in-loop flow analysis (SILFA) system is proposed for the successive catalytic determination of vanadium and iron. The determination of vanadium was based on the p-anisidine oxidation by potassium bromate in the presence of Tiron as an activator to form a reddish dye, which has an absorption maximum at 510 nm. The selectivity of the vanadium determination was greatly improved by adding diphosphate as a masking agent of iron. For the iron determination, an iron-catalyzed oxidative reaction of p-anisidine by hydrogen peroxide with 1,10-phenanthroline as an activator to produce a reddish dye (510 nm) was employed. The SILFA system consisted of two peristaltic pumps, two six-port injection valves, a four-port selection valve, a heater device, a spectrophotometric detector and a data acquisition device. One six-port injection valve was used for the isolation of a mixed solution of standard/sample and reagent to promote each catalytic reaction, and another six-port injection valve was used for switching the reagent for vanadium or iron to achieve selective determination of each analyte. The above mentioned four-port selection valve was used to select standard solutions or sample. These three valves and the two peristaltic pumps were controlled by a built-in programmable logic controller in a touchscreen controller. The obtained results showed that the proposed SILFA monitoring system constituted an effective approach for the selective determination of vanadium and iron. The limits of detection, 0.052 and 0.55 µg L(-1), were obtained for vanadium and iron, respectively. The proposed system was successfully applied to drinking water samples without any preconcentration procedures.

Automatic On-line Solid-phase Extraction-Electrothermal Atomic Absorption Spectrometry Exploiting Sequential Injection Analysis for Trace Vanadium, Cadmium and Lead Determination in Human Urine Samples.

A fully automated sequential injection column preconcentration method for the on-line determination of trace vanadium, cadmium and lead in urine samples was successfully developed, utilizing electrothermal atomic absorption spectrometry (ETAAS). Polyamino-polycarboxylic acid chelating resin (Nobias chelate PA-1) packed into a handmade minicolumn was used as a sorbent material. Effective on-line retention of chelate complexes of analytes was achieved at pH 6.0, while the highest elution effectiveness was observed with 1.0 mol L(-1) HNO3 in the reverse phase. Several analytical parameters, like the sample acidity, concentration and volume of the eluent as well as the loading/elution flow rates, have been studied, regarding the efficiency of the method, providing appropriate conditions for the analysis of real samples. For a 4.5 mL sample volume, the sampling frequency was 27 h(-1). The detection limits were found to be 3.0, 0.06 and 2.0 ng L(-1) for V(V), Cd(II) and Pb(II), respectively, with the relative standard deviations ranging between 1.9 - 3.7%. The accuracy of the proposed method was evaluated by analyzing a certified reference material (Seronorm(TM) trace elements urine) and spiked urine samples.

Successive determination of urinary bilirubin and creatinine employing simultaneous injection effective mixing flow analysis.

A novel four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for successive determination of bilirubin and creatinine in urinary samples. The chemical variables and physical parameters in the flow system were optimized for the enhancement of successive analytical performances. The interferences from urine matrices on the determination of bilirubin and creatinine were eliminated to dilute urine samples. The calibration graphs with the optimum conditions were achieved to be in 0.024-5.0 mg L(-1) for bilirubin and 2-100 mg L(-1) for creatinine. The relative standard deviations (RSDs) at 3 mg L(-1) of bilirubin and at 50 mg L(-1) of creatinine for 11 runs were 1.5 and 1.0%, respectively. The limits of detections (3σ of blank) for bilirubin and creatinine were 7 µg L(-1) and 0.6 mg L(-1), respectively. The sample throughput for stepwise detection was 22 h(-1). The proposed method was applied to the successive determination of bilirubin and creatinine in urine samples.

Highly sensitive determination of trace copper in food by adsorptive stripping voltammetry in the presence of 1,10-phenanthroline.

A highly sensitive, rapid, simple and selective adsorptive stripping assay for the determination of trace copper(II) is proposed. The methodology is based on the adsorptive accumulation of copper(II)-1,10-phenanthroline complexes onto a glassy carbon electrode, followed by oxidation of the adsorbed species by voltammetric scanning using square-wave voltammetry. The influences of experimental variables on the sensitivity of the proposed method, such as the effects of pH, ligand concentration, accumulation time, accumulation potential and interferences, were investigated. Under optimal conditions, the proposed method showed linearity from 0.1 ng mL(-1) to 50 ng mL(-1). The 3 S/N detection limits were 0.0185 ng mL(-1), and the relative standard deviations (n=10) were 0.09-4.71% for intra-day and 0.05-7.14% for inter-day analyses, respectively. The application of the proposed method to the direct analysis of food samples yielded results that agreed with those obtained from including inductively coupled plasma-optical emission spectrometry (ICP-OES) assays according to a paired t-test. The results are a step toward the development of an alternative and reliable analytical method for food research, which requires the direct determination of copper.

Simultaneous injection effective mixing flow analysis of urinary albumin using dye-binding reaction.

A new four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for the determination of urinary albumin. The SIEMA system consisted of a syringe pump, two 5-way cross connectors, four holding coils, five 3-way solenoid valves, a 50-cm long mixing coil and a spectrophotometer. Tetrabromophenol blue anion (TBPB) in Triton X-100 micelle reacted with albumin at pH 3.2 to form a blue ion complex with a λ(max) 625nm. TBPB, Triton X-100, acetate buffer and albumin standard solutions were aspirated into four individual holding coils by a syringe pump and then the aspirated zones were simultaneously pushed in the reverse direction to the detector flow cell. Baseline drift, due to adsorption of TBPB-albumin complex on the wall of the hydrophobic PTFE tubing, was minimized by aspiration of Triton X-100 and acetate buffer solutions between samples. The calibration graph was linear in the range of 10-50µg/mL and the detection limit for albumin (3σ) was 0.53µg/mL. The RSD (n=11) at 30µg/mL was 1.35%. The sample throughput was 37/h. With a 10-fold dilution, interference from urine matrix was removed. The proposed method has advantages in terms of simple automation operation and short analysis time.

Simultaneous injection effective mixing analysis system for the determination of direct bilirubin in urinary samples.

A novel simultaneous injection effective mixing analysis system (SIEMA) for determination of direct bilirubin in urine sample was developed. Bilirubin reacts with diazotized sulfanilic acid in the presence of n-octyl-ß-d-thioglucoside (OTG) as a solubilizing agent to form OTG-azobilirubin. The flow and chemical variables were investigated. A linear calibration graph for direct bilirubin was obtained over the range of 0-1.0 mg L(-1) (r(2)=0.994) with the limit of detection (3σ) of 4.7 µg L(-1), and the relative standard deviation (RSD) being 1.9% (n=11, 0.5 mg L(-1) of direct bilirubin). The results in healthy adult urine obtained by the proposed approach were found in good agreement with those obtained by the batch-wise diazo method.

Flow injection spectrophotometric determination of formaldehyde based on its condensation with hydroxylamine and subsequent redox reaction with iron(III)-ferrozine complex.

A flow injection (FI) spectrophotometric method is proposed for the determination of low concentration of formaldehyde (HCHO) in liquid media. It is based on the condensation of HCHO with hydroxylamine sulfate, followed by the reduction reaction of iron(III)-ferrozine complex with the residual hydroxylamine to form a purple iron(II)-ferrozine complex (λ(max)=562 nm). In the first reaction, hydroxylamine decreases proportionally to the concentration of HCHO, and therefore the produced purple iron(II)-ferrozine complex decreases with increasing HCHO (a negative FI peak is obtained). The detection limit (S/N=3) was 1.6 µg L(-1). The method can be applied to the determination of HCHO in industrial wastewater.

Highly sensitive determination of cadmium and lead in leached solutions from ceramic ware by graphite furnace atomic absorption spectrometry coupled with sequential injection-based solid phase extraction method.

A fully automated pretreatment system based on sequential injection solid-phase extraction (SPE) coupled to a graphite furnace atomic absorption spectrometer (Auto-Pret-GFAAS system) was developed to determine trace amounts of cadmium and lead. A handmade minicolumn packed with a chelating resin was used for the preconcentration of both metals. All protocol for the on-line SPE method was controlled by home-made software. A trigger switch that was placed next to the graphite furnace was used to synchronize the home-made software with built-in software in the GFAAS. One milliliter of sample solution was flowed through into the minicolumn, the analytes were collected and concentrated on the solid phase, and the analytes were eluted with nitric acid (3 M), and detected by GFAAS. The limits of detection (3sigma) for cadmium and lead were 0.20 and 2.6 ng L(-1), respectively. The sample throughput was 47 h(-1) for 1 mL sample loading. The proposed sensitive method with the original Auto-Pret-GFAAS system was applied to the determination of cadmium and lead in tap water and in leached solutions from ceramic ware using 4% acetic acid.

A multiple processing hybrid flow system for analysis of formaldehyde contamination in food.

This work proposes a flow system suitable for the rapid screening of formaldehyde contaminated in food. The system is based on the concept of a flow analyzer with a Hantzsch reaction. An operating procedure was developed for multiple tasking and high sample throughput. This resulted in a significant sample throughput of 51 samples h(-1). Under the optimized conditions, linear calibration from 10 to 100 microM was obtained. The system gave a limit of detection and a limit of quantitation of 0.06 and 0.10 mg kg(-1), respectively. The system was successfully applied to re-hydrated dry squids, vegetables and mushrooms.

Simultaneous injection-effective mixing analysis of palladium.

A novel concept of simultaneous injection-effective mixing analysis (SIEMA) is proposed, and a SIEMA method applied to the spectrophotometric determination of palladium using a water-soluble chromogenic reagent has been demonstrated. The flow configuration of SIEMA is a hybrid format of flow injection analysis (FIA), sequential injection analysis (SIA) and multicommutation in flow-based analysis. Sample and reagent solutions are aspirated into each holding coil through each solenoid valve by a syringe pump, and then the zones are simultaneously dispensed (injected) into a mixing coil by reversed flow toward a detector through a confluence point. This results in effective mixing and rapid detection with low reagent consumption.

Alternative method for measurement of albumin/creatinine ratio using spectrophotometric sequential injection analysis.

A simple, automatic and practical system for successive determination of albumin and creatinine has been developed by combining sequential injection analysis (SIA) and highly sensitive dye-binding assays. Albumin detection was based on the increase in the absorbance due to complex formation between albumin and eosin Y in acidic media. The absorbance of the complex was monitored at 547 nm. For the creatinine assay, the concentration of creatinine was measured by reaction with alkaline picrate to form a colored product which absorbs at 500 nm. The influences of experimental variables such as effects of pH, reagent concentration, standard/sample volume and interferences were investigated. Under optimal conditions, the automated method showed linearity up to 20 mg L(-1) for albumin and 100 mg L(-1) for creatinine. The 3 sigma detection limits were 0.6 and 3.5 mg L(-1) for albumin and creatinine, respectively, and the relative standard deviations (n=10) were 2.49% for 20 mg L(-1) albumin, and 3.14% for 20 mg L(-1) creatinine. Application of the proposed method to the direct analysis of urinary samples yielded results which agreed with those obtained from the Bradford protein assay and a creatinine enzymatic assay according to a paired t-test. The results obtained should be a step towards developing a fully automated and reliable analytical system for clinical research, which requires direct determination of albumin and creatinine and/or its ratios.

Automated stopped-in-dual-loop flow analysis system for catalytic determination of vanadium in drinking water.

An automated stopped-in-dual-loop flow analysis (SIDL-FA) system is proposed for the determination of vanadium in drinking water. The chemistry is based on the vanadium-catalyzed oxidation reaction of p-anisidine by bromate in the presence of Tiron as an activator to produce a dye (lambda(max)=510 nm). A SIDL-FA system basically consists of a selection valve, three pumps (one is for delivering of standard/sample, and others are for reagents), two six-way injection valves, a spectrophotometric detector and a data acquisition device. A 100-microL coiled loop around a heated device is fitted onto each six-way injection valve. A well-mixed solution containing reagents and standard/sample is loaded into the first loop on a six-way valve, and then the same solution is loaded into the second loop on another six-way valve. The solutions are isolated by switching these two six-way valves, so that the catalytic reaction can be promoted. The net waste can be zero in this stage, because all pumps are turned off. Then each resulting solution is dispensed to the detector with suitable time lag. A touchscreen controller is developed to automatically carry out the original SIDL-FA protocol. The proposed SIDL-FA method allows vanadium to be quantified in the range of 0.1-2 microg L(-1) and is applied to the determination of vanadium in drinking water samples.

Advancement of flow-based analysis with alternative chemical reactions and new devices for environmental and biological samples.

This review includes our researches and other methodologies related to flow-based techniques, such as flow injection analysis (FIA) and sequential injection analysis (SIA). The methods will demonstrate semi-and full automated FIA and SIA, including liquid-liquid and liquid-solid extraction. FIA using alternative chemical reactions in the aqueous solution was applied to the trace analysis of metals in biological and environmental samples. For durable liquid-liquid extraction, several phase separators were designed. Moreover, multi-channel FIA with newly designed flow cells and SIA with lab-on-valve devices have been used for the simultaneous and successive determination of metals and organic compounds. On-line solid phase extraction (SPE) has also been proposed for highly sensitive analysis of organic and inorganic compounds.

Flow injection analysis for oxidation state speciation of vanadium(IV) and vanadium(V) in natural water.

A sensitive and simultaneous spectrophotometric flow injection method for the determination of vanadium(IV) and vanadium(V) is proposed. The method is based on the effect of ligands such as 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ) and diphosphate on the conditional redox potential of iron(III)/iron(II) system. A four-channel flow system is assembled. In this flow system, diluted hydrochloric acid (1.0 x 10(-2) mol dm(-3)) as a carrier for standard/sample, acetate buffer (pH 5.5) as a carrier for diphosphate solution, an equimolar mixed solution of iron(III) and iron(II) and a TPTZ solution are delivered, so that the baseline absorbance can be established by forming a constant amount of iron(II)-TPTZ complex (lambda(max) = 593 nm). Vanadium(IV) and/or vanadium(V) (400 microL) and diphosphate (200 microL) solutions are simultaneously introduced into the flow system; in this system the diphosphate solution passes through a delay coil. The potential of the iron(III)/iron(II) system increases in the presence of TPTZ, and therefore vanadium(IV) is easily oxidized by iron(III) to vanadium(V) to produce an iron(II)-TPTZ complex (a positive peak for vanadium(IV) appears). On the other hand, the potential of the redox system decreases in the presence of diphosphate, so that vanadium(V) can be easily reduced by iron(II) to vanadium(IV). In this case, the amount of iron(II) decreases according to the amount of vanadium(V). As a result, the produced iron(II)-TPTZ complex decreases (a negative peak for vanadium(V) appears). In this manner, two peaks for vanadium(IV) and vanadium(V) can be alternately obtained. The limits of detection (S/N = 3) are 1.98 x 10(-7) and 2.97 x 10(-7) mol dm(-3) for vanadium(IV) and vanadium(V), respectively. The method is applied to the simultaneous determination of vanadium(IV) and vanadium(V) in commercial bottled mineral water samples.

Successive determination of urinary protein and glucose using spectrophotometric sequential injection method.

A new sequential injection (SI) system with spectrophotometric detections has been developed for successive determination of protein and glucose. The protein assay is based on ion-association of protein with tetrabromophenolphthalein ethyl ester (TBPE) in the presence of Triton X-100 at pH 3.2. The blue product is monitored for absorbance at 607 nm. For glucose, hydrogen peroxide, generated by the oxidation of glucose in the presence of glucose oxidase immobilized on glass beads packed in a minicolumn, is monitored using iron-catalyzed oxidation reaction of p-anisidine to form a red colored product (520 nm). The SI procedure takes advantage in performing the protein assay during the incubation period for glucose oxidation. Linear ranges were up to 10 mg dL(-1) human serum albumin (HSA) with a limit of detection (LOD) (3sigma) of 0.3 mg dL(-1), and up to 12.5 mg dL(-1) glucose with LOD of 0.08 mg dL(-1). R.S.D.s (n=11) were 2.7% and 2.5% (for 1 mg dL(-1) and 5 mg dL(-1) HSA) and 1.4% (9 mg dL(-1) glucose). Sample throughput for the whole assay of both protein and glucose is 6 h(-1). The automated system has been demonstrated for the successive assay of protein and glucose in urine samples taken from diabetic disease patients, with good agreement with the other methods. This developed SI system is an alternative automation for screening for diabetic diagnosis.