ascorbic-acid and phosphoric-acid

This study analyzed the influence of 10% sodium ascorbate (SA) on tag formation in bleached enamel.. Five groups were tested: G1 - control; G2 - bleaching with 10% carbamide peroxide (CP) + restoration; G3 - CP + SA + restoration; G4 - bleaching with 35% hydrogen peroxide (HP) + restoration; and G5 - HP + SA + restoration. The teeth were sectioned and decalcified, and the resin tags were analyzed at 400X magnification using an optical light microscope and Axiovision software.. The resin tag lengths in µm for each group were as follows: G1 - 36.1A; G2 - 5.8C; G3 - 14.4B; G4 - 1.7D; G5 - 6.5C. Different letters indicate statistically significant differences.. Tooth bleaching with CP or HP impairs the formation of resin tags, and the utilization of sodium ascorbate increases tags length.

Topics: Acid Etching, Dental; Antioxidants; Ascorbic Acid; Carbamide Peroxide; Composite Resins; Dental Bonding; Dental Enamel; Dental Materials; Humans; Hydrogen Peroxide; Image Processing, Computer-Assisted; Materials Testing; Peroxides; Phosphoric Acids; Photochemotherapy; Polymerization; Resin Cements; Saliva, Artificial; Temperature; Time Factors; Tooth Bleaching; Tooth Bleaching Agents; Urea

Nitrite (NO

Topics: Animals; Ascorbic Acid; Biosensing Techniques; Carbon; Cell Line; Drinking Water; Humans; Milk; Nitrites; Nitrogen; Phosphoric Acids; Phosphorus; Polyethyleneimine; Water Pollutants, Chemical

A green, simple, accurate and highly sensitive sequential injection lab-at-valve procedure has been developed for the simultaneous determination of ascorbic acid (Asc) and rutin using 18-molybdo-2-phosphate Wells-Dawson heteropoly anion (18-MPA). The method is based on the dependence of the reaction rate between 18-MPA and reducing agents on the solution pH. Only Asc is capable of interacting with 18-MPA at pH 4.7, while at pH 7.4 the reaction with both Asc and rutin proceeds simultaneously. In order to improve the precision and sensitivity of the analysis, to minimize reagent consumption and to remove the Schlieren effect, the manifold for the sequential injection analysis was supplemented with external reaction chamber, and the reaction mixture was segmented. By the reduction of 18-MPA with reducing agents one- and two-electron heteropoly blues are formed. The fraction of one-electron heteropoly blue increases at low concentrations of the reducer. Measurement of the absorbance at a wavelength corresponding to the isobestic point allows strictly linear calibration graphs to be obtained. The calibration curves were linear in the concentration ranges of 0.3-24mgL

Topics: Anions; Ascorbic Acid; Calibration; Chemistry, Pharmaceutical; Drug Combinations; Flow Injection Analysis; Hydrogen-Ion Concentration; Indicators and Reagents; Limit of Detection; Molybdenum; Phosphoric Acids; Rutin; Sensitivity and Specificity; Tablets

Antiproliferative drugs such as paclitaxel and sirolimus are delivered from stents to inhibit the growth of smooth muscle cells (SMCs) for preventing neointimal hyperplasia. However, these drugs delay the growth of endothelial cells (ECs) as well and cause late stent thrombosis. We recently demonstrated the use of Vitamin-C (l-ascorbic acid, l-AA) over paclitaxel and sirolimus for inhibiting SMCs growth and promoting EC growth simultaneously. In this study, we have investigated the delivery of l-AA from CoCr alloy surfaces for potential use in stents. A polymer-free phosphoric acid (PA) platform and a polymer-based poly(lactic-co-glycolic acid) (PLGA) platform were used for coating l-AA onto CoCr surfaces. For the PA platform, FTIR confirmed that the PA was coated on CoCr, while the AFM showed that the PA coating on the CoCr surface was homogeneous. The successful deposition of l-AA on PA-coated CoCr was also confirmed by FTIR. The uniform distribution of l-AA crystals on PA-coated CoCr was shown by SEM, optical profilometer, and AFM. The drug release studies showed that l-AA (276 μg/cm(2)) was burst released from the PA platform by 1 h. For the PLGA platform, SEM showed that the l-AA incorporated polymer films were smoothly and uniformly coated on CoCr. FTIR showed that l-AA was incorporated into the bulk of the PLGA film. DSC showed that the l-AA was present in an amorphous form and formed an intermolecular bonding interaction with PLGA. The drug release studies showed that l-AA was sustained released from the PLGA coated CoCr for up to 24 h. The SEM, FTIR, and DSC characterizations of samples collected post drug release shed light on the mechanism of l-AA release from PLGA coated CoCr. Thus, this study demonstrated the delivery of l-AA from biomaterial surfaces for potential applications in stents and other implantable medical devices.

Topics: Alloys; Ascorbic Acid; Biocompatible Materials; Calorimetry, Differential Scanning; Cardiovascular Diseases; Chromium Alloys; Drug Carriers; Drug-Eluting Stents; Humans; Lactic Acid; Materials Testing; Microscopy, Atomic Force; Microscopy, Electron, Scanning; Phosphoric Acids; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Prosthesis Design; Prosthesis Failure; Spectroscopy, Fourier Transform Infrared; Thrombosis; Time Factors

The purpose of this in vitro study was to evaluate the immediate shear bond strength of different categories of resin cements on sodium hypochlorite (NaOCl)-treated dentin and to evaluate if the bond was improved by a subsequent treatment with 10% sodium ascorbate before adhesive procedures.. This study tested immediate shear bond strengths to human dentin of 5 resin cements: Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), Multilink (Ivoclar Vivadent), Clearfil Esthetic Cement EX (Kuraray, Tokyo, Japan), SpeedCEM (Ivoclar Vivadent), and Clearfil SA Cement (Kuraray). All cements were tested with no NaOCl pretreatment of the dentin (negative control) and with a 20-minute exposure of the dentin to 6% NaOCl before bonding procedures. The cements found to have decreased bond strengths to NaOCl-treated dentin were tested with the dentin exposed to 10% sodium ascorbate after NaOCl exposure. The sodium ascorbate exposure times tested were 5 seconds and 1 minute.. The mean and standard deviation values for immediate shear bond strength (MPa) for the negative control group were as follows: Variolink II, 18.8 ± 4.2; Multilink, 29.1 ± 7.1; Clearfil Esthetic Cement EX, 20.7 ± 4.9; SpeedCEM, 17.8 ± 4.2; and Clearfil SA Cement, 7.2 ± 2.8. The results for the NaOCl exposure group were as follows: Variolink II, 24.0 ± 6.7; Multilink, 34.1 ± 6.1; Clearfil Esthetic Cement EX, 20.7 ± 6.8; SpeedCEM, 0.0 ± 0.0; and Clearfil SA Cement, 0.1 ± 0.1. The results for the 5-second sodium ascorbate group were the following: SpeedCEM, 8.5 ± 2.6, and Clearfil SA Cement, 4.3 ± 2.0. The following results were found for the 1-minute sodium ascorbate group: SpeedCEM, 12.2 ± 3.2, and Clearfil SA Cement, 4.8 ± 1.0.. The resin cements tested varied in their capacity to adhere to NaOCl-treated dentin. Some resin cements exhibited equal or improved bond strengths (P < .05), whereas others exhibited significantly decreased bond strengths (P < .05). For the susceptible resin cements, a rinse of 10% sodium ascorbate provided an immediate restoration of at least 50% of the original bond strength (P < .05). The efficacy of sodium ascorbate may vary among resin cements.

Topics: Acid Etching, Dental; Adhesiveness; Antioxidants; Ascorbic Acid; Dental Bonding; Dental Pulp Cavity; Dental Stress Analysis; Dentin; Dentin-Bonding Agents; Humans; Materials Testing; Phosphoric Acids; Resin Cements; Shear Strength; Sodium Hypochlorite; Stress, Mechanical; Surface Properties; Time Factors

This study assessed the cross-sectional Knoop microhardness and flexural strength of root dentin exposed to different surface treatments with chemical agents after biomechanical preparation. Root canals from human canines were biomechanically treated and divided into eight groups (n=10) to receive one of the following dentin treatments: I. Deionized water (control); II. 5.25% Sodium hypochlorite (NaOCl); III. NaOCl + 10% Sodium ascorbate (SA); IV. SA; V. 2% Chlorhexidine gel (CHX); VI. 37% Phosphoric acid gel (PA) + CHX; VII. PA; and VIII. PA + NaOCl. The roots were sectioned to obtain specimens that were evaluated for cross-sectional Knoop microhardness and flexural strength using a three-point bending test. ANOVA and Tukey's test were performed. The microhardness in the control group was significantly higher (p < 0.05) than in the groups exposed to chemical agents, which in turn were statistically similar (p > 0.05) to each other. Regarding flexural strength, PA+NaOCl provided statistical higher values than PA+CHX and CHX. However, there was no significant difference between the control group and those groups subjected to surface treatment (p > 0.05). Dentin microhardness was reduced after exposure to NaOCl, CHX, PA, SA and their associations and the flexural strength of radicular dentin was not affected by the chemical agents.

Topics: Analysis of Variance; Ascorbic Acid; Chlorhexidine; Dental Pulp Cavity; Dentin; Disinfectants; Edetic Acid; Hardness Tests; Humans; Materials Testing; Phosphoric Acids; Pliability; Reference Values; Root Canal Irrigants; Root Canal Preparation; Sodium Hypochlorite; Surface Properties

According to previous reports, adverse effects of tooth bleaching on bond strength can be reversed by delaying bonding for 1-3 weeks or by applying 10% sodium ascorbate (SA) for 3 hours or more. This study evaluated the effectiveness of the short-term application of 35% SA to counteract the effects of a 7-day 35% hydrogen peroxide (H2O2) bleaching regimen on bond strength.. Forty extracted third molars were mounted and sectioned to obtain a flat dentin surface and then randomly assigned into 4 groups: group 1: restored, no bleach; group 2: bleached, bonded immediately; group 3: bleached, treated with two 1- minute 35% SA applications before bonding; and group 4: bleached, treated with two 5-minute 35% SA applications before bonding. For bleach treatment in groups 2-4, flattened dentin surfaces were exposed to H2O2 for 7 days at 37°C. Subsequent to respective treatments, dentin surfaces were built up with composite (TPH3 and Prime &Bond NT, Dentsply Caulk, Milford, DE). After 24 hours of storage (100% humidity, 37°C), the specimens were sectioned into 1-mm(2) dentin-composite beams. Four beams from each tooth (n = 40/group) were subjected to microtensile bond strength testing.. Results were as follows: group 1: 18.1 ± 8.1MPa, group 2: 11.3 ± 5.7MPa, group 3: 11.2 ± 5.2MPa, and group 4: 12.6 ± 6.1MPa. A 1-factor analysis of variance and the Tukey post hoc test (α = 0.05) indicated that bleaching had a detrimental effect on bond strength and that short-term SA treatments after bleaching did not significantly improve bond strength.. The application of 35% SA in a clinically relevant timeframe was not effective at reversing bleaching effects on bond strength. Bonding procedures should be delayed following tooth bleaching.

Topics: Acid Etching, Dental; Antioxidants; Ascorbic Acid; Composite Resins; Dental Bonding; Dental Materials; Dentin; Humans; Humidity; Hydrogen Peroxide; Materials Testing; Phosphoric Acids; Polymethacrylic Acids; Random Allocation; Stress, Mechanical; Temperature; Tensile Strength; Time Factors; Tooth Bleaching Agents

A simple, isocratic, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed for the rapid determination of thiamine (VB(1)), niacinamide (VB(3)), pyridoxine (VB(6)), ascorbic acid (VC), pantothenic acid (VB(5)), riboflavin (VB(2)) and folic acid (VB(9)) in Vitamins with Minerals Tablets (VMT). An Alltima C(18) column (250 mm × 4.6 mm i.d., 5 μm) was used for the separation at ambient temperature, with 50mM ammonium dihydrogen phosphate (adjusting with phosphoric acid to pH 3.0) and acetonitrile as the mobile phase at the flow rate of 0.5 ml min(-1). VB(1), VB(3), VB(6), VC and VB(5) were extracted with a solution containing 0.05% phosphoric acid (v/v) and 0.3% sodium thiosulfate (w/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (95:5, v/v), while VB(2) and VB(9) were extracted with a solution containing 0.5% ammonium hydroxide solution (v/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (85:15, v/v). The detection wavelengths were 275 nm for VB(1), VB(3), VB(6), VC, 210 nm for VB(5), and 282 nm for VB(2) and VB(9). The method showed good system suitability, sensitivity, linearity, specificity, precision, stability and accuracy. All the seven water-soluble vitamins were well separated from other ingredients and degradation products. Method comparison indicated good concordance between the developed method and the USP method. The developed method was reliable and convenient for the rapid determination of VB(1), VB(3), VB(6), VC, VB(5), VB(2) and VB(9) in VMT.

Topics: Acetonitriles; Ammonium Hydroxide; Ascorbic Acid; Buffers; Calibration; Chromatography, High Pressure Liquid; Drug Combinations; Drug Stability; Folic Acid; Hydrogen-Ion Concentration; Hydroxides; Limit of Detection; Niacinamide; Pantothenic Acid; Phosphates; Phosphoric Acids; Pyridoxine; Reference Standards; Reproducibility of Results; Riboflavin; Sensitivity and Specificity; Solubility; Tablets; Temperature; Thiamine; Thiosulfates; Time Factors; Vitamins

An experimental conditioner (Exp), which was an aqueous solution of 10% ascorbic acid and 5% ferric chloride, was prepared in this study. This study evaluated the effect of Exp on the microtensile bond strength between a self-curing resin and dentin after long-term water immersion. Flat human dentin surfaces were sequentially pretreated with 40% phosphoric acid, 10% sodium hypochlorite, and Exp. Surface pretreatment with an aqueous solution of 10% citric and 3% ferric chloride (10-3) was used as a control. Composite resin rods were bonded to pretreated dentin surfaces using 4-META/MMA-TBB resin. Microtensile bond strengths were evaluated after water immersion at 24 h, 12 months, 24 months, and 36 months. At each immersion period, the bond strength of Exp was significantly higher than that of 10-3. After 36 months, Exp showed no significant decrease in microtensile bond strength, but 10-3 showed significant reductions. Pretreatment with experimental acid/base conditioner markedly improved the bonding durability of 4-META/MMA-TBB resin to human dentin when compared against the conventional 10-3 treatment.

Topics: Acid Etching, Dental; Ascorbic Acid; Boron Compounds; Chlorides; Citric Acid; Composite Resins; Dental Bonding; Dental Materials; Dentin; Ferric Compounds; Humans; Hydrogen-Ion Concentration; Immersion; Materials Testing; Methacrylates; Methylmethacrylates; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Sodium Hypochlorite; Stress, Mechanical; Tensile Strength; Time Factors; Water

The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste.. Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste. The acidic solutions were characterized by pH value and titratable acidity. Atomic force microscopy (AFM) based nanoindentation was used to study the nano mechanical properties and scanning electron microscopy (SEM) was used to study the morphology of the treated enamel samples and the untreated control areas, respectively.. The investigated acids fell into two groups. The nano hardnesses of MA, TA and CA treated enamel samples (group I) were statistically significantly greater (p<0.05) than the nano hardnesses of PA, AA and LA treated enamel samples (group II). Within each group the nano hardness was not statistically significantly different (p>0.05). The SEM micrographs showed different etch prism morphologies depending on the acid used.. In vitro, the acids investigated led to different erosion effects on human dental enamel, despite their equivalent sensorial acidic taste. This has not been reported previously.

Topics: Acids; Analysis of Variance; Ascorbic Acid; Beverages; Citric Acid; Dental Enamel; Elastic Modulus; Hardness; Humans; Hydrogen-Ion Concentration; Lactic Acid; Malates; Phosphoric Acids; Tartrates; Taste; Tooth Erosion

To evaluate the effects of the elapsed time (ET) after nonvital bleaching (NVB) and sodium ascorbate application (10%) (SAA) on the shear bond strength of dentin to ceramic.. Bovine incisors were selected, internally bleached (35% carbamide peroxide) for 9 days and submitted to the following treatments (n = 10): G1, G2, G3-luting after 1, 7, and 14 days; G4, G5, and G6-luting after SAA, 1, 7, and 14 days, respectively. G7 and G8 were not bleached: G7-luting 24 hours after access cavity sealing; G8-luting 24 hours after access cavity sealing after SAA. After NVB, the vestibular dentin was exposed and flattened. The SAA was applied to the dentin (G4, G5, G6, G8) for 10 minutes, and it was then washed and dried. The dentin was etched (37% phosphoric acid), and an adhesive system (Single Bond 2) was applied. Feldspathic ceramic discs (VM7; 4-mm diameter, 3-mm thick) were luted with a dual-resin agent (RelyX ARC, 3M ESPE Dental Products, St. Paul, MN). After 24 hours, specimens were submitted to shear test on a universal testing machine. The data (MPa) were submitted to ANOVA and Dunnet's test (5%).. The means (+/- SD) obtained were (MPa): G1 (14 +/- 4.5), G2 (14.6 +/- 3.1), G3 (14 +/- 3.7), G4 (15.5 +/- 4.6), G5 (19.87 +/- 4.5), G6 (16.5 +/- 3.7), G7 (22.8 +/- 6.2), and G8 (18.9 +/- 5.4). SAA had a significant effect on bond strength (p= 0.0054). The effect of ET was not significant (p= 0.1519). G5 and G6 presented higher values than the other bleached groups (p < 0.05) and similar to G7 and G8 (p > 0.05).. After NVB, adhesive luting to dentin is recommended after 7 days if sodium ascorbate has been applied prior to dentin hybridization.

Topics: Acid Etching, Dental; Adhesiveness; Aluminum Silicates; Animals; Antioxidants; Ascorbic Acid; Bisphenol A-Glycidyl Methacrylate; Carbamide Peroxide; Cattle; Cementation; Dental Bonding; Dental Cements; Dental Porcelain; Dental Pulp Cavity; Dentin; Dentin-Bonding Agents; Hydrofluoric Acid; Materials Testing; Oxidants; Peroxides; Phosphoric Acids; Polyethylene Glycols; Polymethacrylic Acids; Potassium Compounds; Random Allocation; Resin Cements; Shear Strength; Stress, Mechanical; Time Factors; Tooth Bleaching; Tooth, Nonvital; Urea

Lack of post-sampling stability of ascorbate and dehydroascorbic acid and failure to block their in vivo equilibrium have lowered their value as biomarkers of oxidative stress and limited the ability to further investigate their possible role in disease prevention. In the present article, analytic reproducibility was tested by repeated analysis of plasma aliquots from one individual over 4 years. The plasma was subjected to acidic deproteinization with an equal volume of 10% meta-phosphoric acid containing 2 mmol/L of EDTA and analyzed for ascorbate and dehydroascorbic acid by high-performance liquid chromatography with coulometric detection. In a parallel experiment, the stability of human plasma samples treated as above and stored at -80 degrees C for 5 years was tested in a cohort of 131 individuals. No degradation or shift in the equilibrium between ascorbate and dehydroascorbic acid was observed in either of the experiments. In conclusion, ascorbate and dehydroascorbic acid could be adequately preserved in plasma stored at -80 degrees C following acidic deproteinization with meta-phosphoric acid containing 2 mmol/L of EDTA.

Topics: Ascorbic Acid; Biomarkers; Dehydroascorbic Acid; Humans; Hydrogen-Ion Concentration; Oxidative Stress; Phosphoric Acids; Reproducibility of Results

2-DE separations of protein extracts sometimes have problems with poor resolution and streaking. This problem is particularly apparent with microorganisms, most notably those with a large cell wall. Here we describe a novel, rapid protocol for the extraction of microorganisms in acidic conditions, leading to increased resolution and 2-D gel quality. The efficiency of the protocol is demonstrated with extracts of bacteria, Escherichia coli and Bacillus subtilis; fungus, Trichoderma harzianum and yeast, Saccharomyces cerevisiae. We also demonstrate using a membrane centrifugal filtration, that large acidic molecules in excess of 100 kDa, probably including cell wall material, are responsible for the separation difficulties. A range of acidic extraction conditions were investigated, and it was found that optimal extraction is achieved using an extraction solution acidified to pH 3 by 80 mM citric acid. These findings have significant implications for the proteomic study of many medically, agriculturally and environmentally significant microorganisms, as the cell walls of these organisms are often considerably more complex than many commonly studied laboratory strains.

Topics: Acids; Artifacts; Ascorbic Acid; Bacillus subtilis; Cell Wall; Citric Acid; Electrophoresis, Gel, Two-Dimensional; Escherichia coli; Hydrogen-Ion Concentration; Mass Spectrometry; Phosphoric Acids; Saccharomyces cerevisiae; Trichoderma

It has been reported that the tensile bond strength between the 4-META/MMA-TBB resin and dentin pretreated with 10% citric/3% ferric chloride solution decreased after immersion in water for 2 years. The current study investigated the effect of an experimental dentin conditioner on the bonding of 4-META/MMA-TBB resin to dentin after thermocycling. The experimental conditioner was an aqueous solution of 10% ascorbic acid and 5% ferric chloride (Exp). Human teeth were prepared to expose flat dentin surfaces. These were treated sequentially with 40% phosphoric acid, 10% sodium hypochlorite, and the experimental conditioner. A commercially available dentin conditioner, an aqueous solution of 10% citric/3% ferric chloride (10-3) was used for a control group. Stainless steel rods were bonded to the pretreated dentin surfaces with the use of the 4-META/MMA-TBB resin. Tensile bond strengths were determined after 0, 5,000, 10,000, 20,000 themocycles. All data were analyzed by ANOVA, and differences among groups were analyzed by Duncan's new multiple range test (n = 10, p < 0.05). The experimental group showed no significant decrease in bond strength through 20,000 thermocycles, while the control group exhibited significant decrease after 10,000 thermocycles. Mean bond strength of the experimental groups were significantly higher than those of the control group at both 10,000 and 20,000 thermocycles. A hybrid layer could not be identified in SEM micrographs of the experimental groups. 10-3-conditioned specimen SEMs displayed crack formation between the adhesive resin and a hybrid layer. The experimental dentin pretreatment improved the bond strength of a 4-META/MMA-TBB resin to human dentin compared to 10-3 treatment after thermocycling.

Topics: Acid Etching, Dental; Analysis of Variance; Ascorbic Acid; Biocompatible Materials; Chlorides; Dental Bonding; Dentin; Dentin-Bonding Agents; Ferric Compounds; Hot Temperature; Humans; Materials Testing; Methacrylates; Microscopy, Electron, Scanning; Phosphoric Acids; Resin Cements; Sodium Hypochlorite; Surface Properties; Tensile Strength; Time Factors; Tooth; Water

The aim of the present work was to develop validated HPLC method using electrochemical detector for simultaneous detection of low molecular weight antioxidants (LMWA) in urinary bladder. Furthermore, the method was applied to study the distribution of LMWA in urinary bladder wall. The ascorbic acid (AA), glutathione in reduced (GSH) and oxidized (GSSG) form and uric acid (UA) were resolved by isocratic elution from C18 reversed-phase column. The bladder tissue sample preparation involved extraction with meta-phosphoric acid solution for LMWA stabilization. The AA, GSH and UA tissue peak was identified by different approaches. The obtained method validation parameters were in acceptable range: intra-day precision (<4.4%), intra-day accuracy (<8.4%), inter-day precision (<9.4%) and inter-day accuracy (<15.6%). Additionally, the method provided good linearity (r2>0.99) and recoveries (98.9-112.6%). The distribution of LMWA in urinary bladder was determined by measuring their concentration in bladder wall layers: urothelium, lamina propria, muscularis and serosa. The validated method was able to quantify the reduced form of all three LMWA in all four bladder wall layers. The LMWA concentrations were decreasing from urothelium to serosa except of UA. The developed HPLC method with electrochemical detection of LMWA is simple, fast and can be used for simultaneous quantification of LMWA in tissues, which contain low concentrations of antioxidants.

Topics: Animals; Antioxidants; Ascorbic Acid; Chromatography, High Pressure Liquid; Electrochemistry; Glutathione; Glutathione Disulfide; Molecular Weight; Muscle, Smooth; Phosphoric Acids; Serous Membrane; Swine; Technology, Pharmaceutical; Tissue Extracts; Uric Acid; Urinary Bladder; Urothelium

The purpose of this study was to investigate the efficacy of an experimental dentin primer consisting of ascorbic acid (AA) and ferric chloride (Fe). Three exprimental primers - 10 wt%AA and 0.075 wt%Fe (i.e., 10AA-0.075Fe), 10AA-0Fe, and 0AA-0.075Fe - were prepared. Flattened dentin surfaces were first treated with phosphoric acid and NaClO, and subsequently primed using each experimental solution. Besides the experimental solutions, 10 wt% citric acid and 3 wt% ferric chroride (10CA-3Fe) was also used. A stainless steel rod was bonded to the dentin surface with Super-Bond C&B. 10CA-3Fe/Super-Bond C&B was then used as a control. Tensile bond strengths were evaluated after 24-hour immersion in water. 10AA-0.075Fe showed significantly high bond strength compared to 10AA-0Fe, 0AA-0.075Fe, 0AA-0Fe, and 10CA-3Fe. No significant differences were found between 10AA-0.075Fe and Super-Bond C&B system. The experimental primer consisting of 10 wt% ascorbic acid and 0.075 wt% ferric chloride improved the bonding between Super-Bond C&B and dentin conditioned with phosphoric acid and NaClO.

Topics: Acid Etching, Dental; Acrylic Resins; Analysis of Variance; Ascorbic Acid; Boron Compounds; Chlorides; Dental Bonding; Dental Stress Analysis; Dentin; Dentin-Bonding Agents; Ferric Compounds; Humans; Materials Testing; Methacrylates; Methylmethacrylates; Molar; Phosphoric Acids; Resin Cements; Sodium Hypochlorite; Tensile Strength

A simple, reliable high-performance liquid chromatographic method was developed to measure ascorbic acid (ASC), with ultraviolet detection (250 nm), in human plasma and urine. Immediately following blood withdrawal, the heparinized plasma samples were deproteinized with 10% m-phosphoric acid, while the freshly voided urine samples were diluted with m-phosphoric acid. ASC was separated on a reversed-phase column by elution with 0.1 M KH2PO4 adjusted to pH 2.35. In urine, after reduction of dehydroascorbic acid to ASC, total ASC was measured using the same mobile phase. The method was sensitive down to 0.1 and 0.4 mg ASC per litre of urine and plasma, respectively. In patients with idiopathic calcium urolithiasis, both plasma and urinary ASC were within the range observed in age-matched controls.

Topics: Adult; Aged; Ascorbic Acid; Calcium; Chromatography, High Pressure Liquid; Female; Humans; Male; Middle Aged; Phosphoric Acids; Quality Control; Reference Values; Sensitivity and Specificity; Urinary Calculi

A method is described for estimating plasma and urinary hemoglobin concentrations as low as 3 mg/L. The assay measures at 528 nm the rate of peroxidation of chlorpromazine by hemoglobin and is not affected by ascorbate and bilirubin concentrations up to 500 mumol/L. Results by this method (mean +/- SD: 54.4 +/- 41.6 mg/L; n = 19) correlated well with those by a scanning spectrophotometric method (52.5 +/- 41.6 mg/L; r = 0.96) and a Coulter Instrument method (r = 0.99; Coulter method: 125 +/- 15 g/L; rate method: 122 +/- 15 g/L; n = 10, r = 0.99). The correlation for assays of 20 plasma samples by our method and a tetramethylbenzidine method was also good (r = 0.95) though the latter gave lower results (31.1 +/- 31.6 mg/L) than the chlorpromazine method (50.9 +/- 41.1 mg/L). The chlorpromazine rate method gave an intra- and interday CV of 7.9% and 9.7%, respectively, at a hemoglobin concentration of 31 mg/L.

Topics: Adult; Ascorbic Acid; Bilirubin; Chlorpromazine; Female; Hemoglobins; Hemoglobinuria; Humans; Hydrogen Peroxide; Kinetics; Male; Middle Aged; Phosphoric Acids; Reference Values; Spectrophotometry