chloramine-T Solution Research Articles

Canal disinfection using Nd: YAG Laser, synchronized microbubble-photodynamic activation, and carbon quantum dots on microhardness, smear layer removal, and extrusion bond strength of zirconia post to canal dentin. An invitro scanning electron microscopic analysis.

Evaluation of the impact of the latest root canal disinfectant, that is carbon quantum dots (CQDs), synchronized microbubble-photodynamic activation (SYMPA), and Nd: YAG laser along with ethylenediaminetetraacetic acid (EDTA) as a final irrigant on the Marten hardness (MH), smear layer (SL) removal, and extrusion bond strength (EBS) of zirconia post to the canal dentin. Eighty intact single-rooted premolars were obtained and disinfected using 0.5% chloramine-T solution. Root canal preparation was performed using ProTaper files followed by obturation. The post space was prepared for prefabricated zirconia post and all the teeth were randomly divided into four groups based on the disinfection used (n = 20 each) Group 1: 5.25% NaOCl + 17% EDTA (Control), Group 2: Nd: YAG laser + 17% EDTA, Group 3: SYMPA + 17% EDTA, and Group 4: CQDs + 17% EDTA. MH, SL removal, and EBS of zirconia post-bonded to root dentin were performed using a microhardness tester, scanning electron microscope (SEM), and universal testing machine, respectively. Both intragroup and intergroup comparisons were performed using one-way analysis of variance (ANOVA) and posthoc-Tukey test for significant difference (p < .05). Group 2 samples (Nd: YAG laser + 17% EDTA) (0.24 ± 0.06 GPa) exhibited highest values of MH. Samples in group 3 (SYMPA + 17% EDTA) treated teeth unveiled the lowest MH scores (0.13 ± 0.02 GPa). Moreover, the coronal third of Group 3 specimens (SYMPA and 17% EDTA) (1.54 ± 0.31) eliminated SL from the canal with the greatest efficacy as well as presented the highest EBS (10.13 ± 0.69 MPa). However, the apical third of Group 1 samples (5.25% NaOCl + 17% EDTA) (2.95 ± 0.33) exhibited the least efficient elimination of SL from the radicular dentin as well as the lowest bond strength (5.11 ± 0.19 MPa) of zirconia post to the dentin. The SYMPA technique with 17% EDTA proved highly effective in removing the SL from canal dentin and enhancing the EBS of zirconia posts. The least preferable method for SL removal and MH improvement was found to be 5.25% NaOCl + 17% EDTA. CQDs and Nd: YAG laser demonstrated satisfactory smear layer removal properties from the canal, along with achieving appropriate bond strength of zirconia posts. RESEARCH HIGHLIGHTS: Nd: YAG laser and 17% EDTA as canal disinfectant exhibited the highest values of MH. Specimens irrigated with SYMPA and 17% EDTA eliminated SL from the canal with the greatest efficacy. The coronal third of Group 3 (SYMPA + 17% EDTA) samples unveiled the highest zirconia post-bond integrity score to the canal dentin. Cohesive failure was a dominant failure type among different experimental groups.

Effects of Short-Term Exposure of Chloramine-T Solution on the Characteristics of Light-Cured and Chemical-Cured Adhesives.

This study evaluated the effect of a 0.5% chloramine T solution on a chemical-cured universal adhesive by comparing the light-cured, one-step, self-etch adhesive for the bonding performance, mechanical properties, and resin-dentin interfacial characteristics. Caries-free human molars were randomly assigned into eight groups based on the bonding systems employed (Bond Force II, BF and Bondmer Lightless, BL), the immersion solutions used before bonding (0.5% chloramine T solution and distilled water), and the immersion durations (5 and 60 min). Microtensile bond strength (μTBS), nanoleakage evaluation, and nanoindentation tests were performed, and the surface morphology of the resin-dentin interface was examined using a focus ion beam/scanning ion microscopy system. Immersion in chloramine-T for 5 min significantly decreased the μTBS of Bondmer Lightless (from 22.62 to 12.87 MPa) compared with that in distilled water. Moreover, there was also a decreasing trend after immersing in chloramine-T for 60 min (from 19.11 to 13.93 MPa). Chloramine T was found to have no effect on the hardness, elastic modulus, or morphological characteristics of the ion-beam milled resin-dentin interfacial surfaces in the tested adhesives, suggesting that chloramine T might reduce the bond strength by interfering with the interaction and the sealing between the adhesive resin and dentin in the chemical-cured universal adhesive, albeit without affecting the mechanical properties.

Alternatives to amalgam: Is pretreatment necessary for effective bonding to dentin?

The aim of this study was to determine whether pretreatment of the dentin surface is beneficial or not by analysis of the bond strengths of four self-adhesive restoratives and four restoration materials where pretreatment of dentin was necessary. Bovine incisors (n=160) were ground flat on the labial surfaces to expose dentin using a grinder and silicon carbide (SiC) abrasive papers under running water. Between preparation and bonding procedures, the crowns were stored in Chloramine-T solution at 4°C. Eight different restorative materials were studied: Activa BioActive (ABA), Cention Forte (CNF), Ceram.x Spectra ST (CXS), Riva self-cure (RSC), Equia Forte (EQF), Fuji II LC (FJI), Ketac Molar (KTM), Surefil one (SFO). Four materials required pretreatment of the dental hard tissue before placement, whereas the other four were self-adhesive (no pretreatment). The specimens were mounted vertically in plaster. A preload of 5N was applied and the subsequent cross-head speed was 0.8mm/min. Shear bond strengths (MPa) were calculated as the failure load divided by the bonding area. Failure modes were recorded as adhesive, cohesive or pretest. Data were statistically analyzed via ordinal regression for inference and Tukey's method to adjust for multiple comparisons. All computations were done using R version 4.1.2 (R Core Team 2021). Smax (failure stress in MPa) of the combined groups with pretreatment were significantly higher than the self-adhesive materials. The highest frequency of pretest-failure was seen with FJI. Glass-ionomer cements without pretreatment were the only restoratives with pretest failures. Amongst materials without pretreatment, SFO had the highest bond strengths. The further reduction of the placement steps for materials used as an amalgam alternative, namely the omission of pretreatment of the dentin, results in these self-adhesive materials having lower bond strengths than materials that require pretreatment of the dentin.

The Effects of Various Hemostatic Agents on Shear-bond Strength in Primary Teeth: An In Vitro Study

Aims and objectives: The aim of this study was to determine the effects of chitosan, Ankaferd Blood Stopper® (ABS, Ankaferd Health Products Ltd, Turkey), and ferric sulfate (FS) on the shear-bond strength of the self-etch adhesive to primary tooth dentin. Materials and methods: The occlusal surfaces of 80 extracted human primary teeth (stored in a 0.5% chloramine-T solution at 4oC) were ground flat, exposing the dentin. The teeth were divided into 4 groups: chitosan, ABS, FS, and control. Hemostatic agents were applied to the teeth, and then they were rinsed with distilled water and air dried. In the control group, the teeth were only rinsed with distilled water and slightly air dried. A self-etch adhesive was applied, and the composite cylinder was created on all the samples. Shear-bond strength was tested with a universal testing machine. Failure mode analysis was performed using scanning electron microscopy. Results: The study revealed no statistically significant difference between the hemostatic agent and control groups in terms of bond strength ( P &gt;.05). The highest bond strength was observed in the chitosan group. In this group, a statistically significant difference between chitosan and ABS was observed ( P &lt;.05). The adhesive failure was the predominant failure mode in all the groups. Conclusions: These findings suggest that chitosan, ABS, and FS have no adverse effects on the bonding of the self-etch adhesive to primary teeth dentin.

The safety and efficacy of 'over the counter' bleaching products in the UK.

Introduction EU council directive 2011/84/EU resulted in a demand for over the counter (OTC) bleaching products. The industry has latched onto this renewed demand by developing a range of non-hydrogen peroxide OTC products. Aims To determine whether non-hydrogen peroxide OTC whitening products available in the UK are safe and to determine the lightening effect of those products. Materials and methods A total of 21 extracted teeth (11 incisors and ten premolars) were collected and stored in chloramine-T solution. Five days before the study, all teeth were immersed in 5 ml of a standard green tea solution at room temperature (22±2 °C). Roots were sectioned from the teeth and cleaned using an ultrasonic bath. Teeth were then embedded in epoxy resin and sectioned inciso-gingivally to serve as paired test and control specimens. A positive control of 10% carbamide peroxide was used while saline was used as a negative control. Five OTC products were selected from two major British consumer outlets. Initially, products were applied to the teeth samples for two one-hour cycles, followed by the equivalent of one-week's application, according to the manufacturer's instruction. Samples were stored overnight in saline to minimise any effects of dehydration. Shades of teeth were taken blindly by a single trained clinician in a natural light environment against a grey background before and after application of the products. Vickers microhardness tests and scanning electron microscopy (SEM) analysis were undertaken. Results SEM analysis showed surface morphology alterations to varying degrees, with several samples demonstrating a distinct etching pattern post-exposure to the OTC products. Sample three ('Brilliant 5 minute kit') and sample five ('iWhite instant teeth whitening') produced the most extensive surface alterations. Samples three and five also resulted in a significant reduction (p = 0.008) in Vickers microhardness. Two OTC products resulted in a lightening effect less than the negative control saline, whereas two other OTC products resulted in a lightening effect greater than carbamide peroxide. Conclusion This study suggests that non-hydrogen peroxide OTC products have the potential to damage enamel and lighten teeth. The lightening effect of the OTC products is variable, however, it is most likely to occur in sodium chlorite based products.

A Comparison of Coronal Tooth Discoloration Elicited by Various Endodontic Reparative Materials

IntroductionThe purpose of this study was to evaluate coronal tooth discoloration of ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN), white ProRoot MTA, EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), MTA Angelus (Angelus Solucoes Odontologicas, Londrina, Brazil), and Biodentine (Septodont, Saint Maur des Fosses, France) when used in an ex vivo pulpotomy model. MethodsFreshly extracted mandibular third molars were collected and stored in 1% chloramine-T solution. Teeth were randomly assigned into 6 groups (n = 15) and stored individually in phosphate buffered saline at 37°C in 100% humidity. A standardized endodontic access was made in 5 groups. A 3-mm-thick increment of reparative material was placed on the pulpal floor, covered by glass ionomer, and the access opening restored with composite. Color (Commission Internationale de l'eclairage L*a*b*) was recorded with the Vita Easy Shade spectrophotometer (VITA Zahnfabrik, Bad Säckingen, Germany) on the midbuccal surface at baseline; after access preparation; after material placement; and then after 1, 7, 30, and 60 days. Changes in Commission Internationale de l'eclairage L*a*b* were measured for each experimental group and compared with ProRoot MTA (positive control) and no treatment (negative control) using the following equation: ΔE = ([Li − L0*]2 + [ai − a0*]2 + [bi − b0*]2)1/2. The mean results were analyzed within each group and between groups using the Friedman 2-way analysis post hoc test (P < .05). ResultsThere were no significant differences between white ProRoot MTA, MTA Angelus, and the positive control group. EndoSequence Root Repair Material and Biodentine produced significantly less discoloration than white ProRoot MTA, MTA Angelus, and ProRoot MTA. ConclusionsUnder the conditions of this study, EndoSequence and Biodentine had significantly less discoloration compared with white ProRoot MTA, MTA Angelus, and ProRoot MTA. The potential for discoloration may or may not correlate when materials are used clinically.

Chloramine-induced anaphylaxis while showering: a case report

IntroductionSodium-N-chlorine-p-toluene sulfonamide, commonly known as chloramine-T, is a derivative of chlorine which is widely used as a disinfectant. For many years, chloramine-T has been described as a cause of immediate-type hypersensitivity, especially with regard to asthma and rhinitis, and as a cause of occupational dermatoses in cleaning personnel in hospitals, although no anaphylactic reaction has yet been reported. Hence, to the best of our knowledge we present the first case of anaphylaxis to chloramine-T with evidence of specific immunoglobulin E antibodies.Case presentationWe describe the case of a 25-year-old Caucasian woman who was in good health and with a negative history for atopy, including no respiratory symptoms of rhinitis or asthma, and with no professional exposure to chloramine-T. She, while showering, applied a chloramine-T solution to a skin area with folliculitis on her leg, and within a few minutes developed generalized urticaria and angioedema, followed by vomiting and collapse with loss of consciousness. A skin prick test with a chloramine-T solution at 10mg/mL concentration was positive, and specific immunoglobulin E to chloramine-T was quantified at a value of 2.9 optical density as measured by the enzyme allergosorbent test technique.ConclusionThe strict cause-effect relationship and the results of the skin test and the in vitro test make certain the causative role of chloramine-T in this case of anaphylaxis. This suggests that chloramine-T, based on its wide use as a disinfectant, should be considered a possible cause in anaphylaxis of unknown origin.

The Role of Integrin-linked Kinase in Liver Wound Healing

Liver wound healing is an integrated process in which hepatic stellate cells play a major role. We hypothesized that the cellextracellular signaling protein integrin-linked kinase (ILK) is important in transducing signals from the extracellular matrix to stellate cells and thus plays a critical role in stellate cell activation and fibrogenesis during liver injury. Liver injury and subsequent stellate cell activation led to a 3-fold increase in ILK expression and increased kinase activity. Overexpression of ILK in isolated stellate cells led to enhanced motility and adhesion as well as increases in smooth muscle alpha-actin and type I collagen mRNA expression. The effects of ILK on stellate cell phenotypes were phosphatidylinositol 3-kinase-dependent. Forced expression of ILK in vivo led to increases in type I collagen, smooth muscle alpha-actin, transforming growth factor-beta, and extra domain A (EDA) fibronectin mRNAs (by 3.2-, 3.5-, 2.5-, and 2.2-fold, respectively; n = 8, p < 0.05 for each versus the control), whereas inhibition of ILK in vivo led to significant reductions in these mRNAs. Morphometric analysis revealed that ILK overexpression led to a 31.4% increase in liver collagen content (n = 8, p < 0.05 versus the control); in contrast ILK knockdown in vivo led to a significant reduction in fibrogenesis. We conclude that ILK plays an important pathophysiological role in vivo in liver wound healing.

Sequential injection spectrophotometric determination of trace amounts of iodide by its catalytic effect on the 4,4′-methylenebis( N,N-dimethylaniline)-chloramine-T reaction

A simple and sensitive sequential injection spectrophotometric procedure is proposed for the determination of trace amounts of iodide in pharmaceutical preparations. The method is based on the catalytic effect of iodide on the (tetra base) 4,4′-methylenebis( N,N-dimethylaniline)-chloramine-T reaction in acidic solution. The method involves a sequential aspiration of 255 μl sample/standard followed by 170 μl tetra base and then 128 μl chloramine-T solutions into a carrier stream to be stacked inside a holding coil and flow reversed through a reaction coil towards a detector. The resulting colored compound is measured at 600 nm using an UV/Vis-spectrophotometer. All the parameters that affect the reaction were evaluated and the calibration curve is linear over a range of 0.1–6.0 μg l −1 of iodide concentration with detection limit of 0.05 μg l −1. A sample throughput of 80 samples per hour and relative standard deviation of less than 2.0% was achieved. The method is successfully applied for the determination of iodide in three different samples (tablets).

The Effect of Thrombocytopenia on Dermal Wound Healing

The Effect of Thrombocytopenia on Dermal Wound Healing

Antimicrobial activity of a new intact skin antisepsis formulation

Different antiseptic formulations have shown limitations when applied to disinfecting intact skin, notably short-term tolerability and/or efficacy. The purpose of this study was optimizing a new antiseptic formulation specifically targeted at intact skin disinfection and evaluating its in vitro microbicidal activity and in vivo efficacy. Methods: The biocidal properties of the antiseptic solution containing 0.5% chloramine-T diluted in 50% isopropyl alcohol (Cloral; Eurospital SpA Trieste, Italy) were measured in vitro versus gram-positive-, gram-negative-, and acid-alcohol-resistant germs and fungi with standard suspension tests in the presence of fetal bovine serum. Virus-inhibiting activity was evaluated in vitro against human cytomegalovirus, herpes simplex virus, poliovirus, hepatitis B virus, and hepatitis C virus. Tests used different methods for the different biologic and in vitro replication capacity of these human viruses. Lastly, Cloral tolerability and skin colonization retardation efficacy after disinfection were studied in vivo. Results: The antiseptic under review showed fast and sustained antimicrobial activity. The efficacy of Cloral against clinically important bacterial and viral pathogens and fungi was highlighted under the experimental conditions described in this article. Finally, microbial regrowth lag and no side effects were documented in vivo after disinfection of 11 volunteers. Conclusions: A stable chloramine-T solution in isopropyl alcohol may be suggested for intact skin antisepsis. (Am J Infect Control 2002;31:117-23.)

A simple analytical procedure to replace HPLC for monitoring treatment concentrations of chloramine-T on fish culture facilities

Concentrations of chloramine-T must be monitored during experimental treatments of fish when studying the effectiveness of the drug for controlling bacterial gill disease. A surrogate analytical method for analysis of chloramine-T to replace the existing high-performance liquid chromatography (HPLC) method is described. A surrogate method was needed because the existing HPLC method is expensive, requires a specialist to use, and is not generally available at fish hatcheries. Criteria for selection of a replacement method included ease of use, analysis time, cost, safety, sensitivity, accuracy, and precision. The most promising approach was to use the determination of chlorine concentrations as an indicator of chloramine-T. Of the currently available methods for analysis of chlorine, the DPD ( N, N-diethyl- p-phenylenediamine) colorimetric method best fit the established criteria. The surrogate method was evaluated under a variety of water quality conditions. Regression analysis of all DPD colorimetric analyses with the HPLC values produced a linear model ( Y=0.9602 X+0.1259) with an r 2 value of 0.9960. The average accuracy (percent recovery) of the DPD method relative to the HPLC method for the combined set of water quality data was 101.5%. The surrogate method was also evaluated with chloramine-T solutions that contained various concentrations of fish feed or selected densities of rainbow trout. When samples were analyzed within 2 h, the results of the surrogate method were consistent with those of the HPLC method. When samples with high concentrations of organic material were allowed to age more than 2 h before being analyzed, the DPD method seemed to be susceptible to interference, possibly from the development of other chloramine compounds. However, even after aging samples 6 h, the accuracy of the surrogate DPD method relative to the HPLC method was within the range of 80–120%. Based on the data comparing the two methods, the U.S. Food and Drug Administration has concluded that the DPD colorimetric method is appropriate to use to measure chloramine-T in water during pivotal efficacy trials designed to support the approval of chloramine-T for use in fish culture.

Enhancement of Cell Adhesion and Spreading by a Cartilage-specific Noncollagenous Protein, Cartilage Matrix Protein (CMP/Matrilin-1), via Integrin α1β1

Cartilage matrix protein (CMP; also known as matrilin-1), one of the major noncollagenous proteins in most cartilages, binds to aggrecan and type II collagen. We examined the effect of CMP on the adhesion of chondrocytes and fibroblasts using CMP-coated dishes. The CMP coating at 10-20 micrograms/ml enhanced the adhesion and spreading of rabbit growth plate, resting and articular chondrocytes, and fibroblasts and human epiphyseal chondrocytes and MRC5 fibroblasts. The effect of CMP on the spreading of chondrocytes was synergistically increased by native, but not heated, type II collagen (gelatin). The monoclonal antibody to integrin alpha1 or beta1 abolished CMP-induced cell adhesion and spreading, whereas the antibody to integrin alpha2, alpha3, alpha5, beta2, alpha5beta1, or alphaVbeta5 had little effect on cell adhesion or spreading. The antibody to integrin alpha1, but not to other subunits, coprecipitated 125I-CMP that was added to MRC5 cell lysates, indicating the association of CMP with the integrin alpha1 subunit. Unlabeled CMP competed for the binding to integrin alpha1 with 125I-CMP. These findings suggest that CMP is a potent adhesion factor for chondrocytes, particularly in the presence of type II collagen, and that integrin alpha1beta1 is involved in CMP-mediated cell adhesion and spreading. Since CMP is expressed almost exclusively in cartilage, this adhesion factor, unlike fibronectin or laminin, may play a special role in the development and remodeling of cartilage.

Occupational asthma due to chloramine-T solution

Occupational asthma due to chloramine-T solution

てんかん患者における血清中Ｂｒｏｍｉｄｅの測定と臨床応用

Bromide (Br) serum concentrations were determined by the spectrophotometric assay in patients with epilepsy to whom Br and other antiepileptic drugs were administered. Serum samples or standard solutions (0-2, 000μg/ml) were pretreated by adding perchloric acid, and were centrifuged. Twenty μl of the supernatant was transferred to the 10ml test tube, and 0.2mol/l acetate buffer (pH5.5) and 0.625mmol/l sodium fluorescein were added to it. After 200μl of 8mmol/l chloramine-T solution was added and was incubated for 10min, the reaction was stopped by adding sodium thiosulfate and sodium carbonate solution. The absorbance was determined at 520nm by spectrophotometer. Coefficients of variations (CVs) were 1.7 to 2.2% in within-day assay (n=10) and 3.5 to 4.9% in between-day assay (10 days). The recovery rate of Br ranged from 91.5 to 109.9% (mean 102.7%). This method was not interfered by other various anti-epileptic drugs. We observed that epileptic attacks were clearly suppressed by KBr administration in a patient with intractable epilepsy who had not been controlled by high doses of valproate-Na and phenobarbital therapy. In this patient, Br serum concentration for suppressing the epileptic attacks was from 1, 560 to 1, 640μg/ml. The present method for determining Br serum concentration was so simple, rapid and accurate, i. e., being useful for monitoring the Br serum concentration in the therapy of epilepsy.

Chloramine-T solutions: effect on wound healing in guinea pigs.

An evaluation of the wound-healing and disinfectant activities of chloramine-T (Chlorazene) used in hydrotherapy whirlpools was studied in a guinea pig cutaneous wound model. Standard microbiologic methods were used to determine the bacteriocidal activity of Chlorazene in cultures containing up to 2.03 x 10(6) colony-forming units per milliliter of Pseudomonas aeruginosa. Full-thickness skin wounds in 40 guinea pigs were inoculated with Pseudomonas aeruginosa and all animals allowed to recover from anesthesia. Twenty-four hours later, animals were placed in water only or water containing Chlorazene (300ppm) for 20 minutes. This procedure was repeated daily for up to seven days after inoculation of wounded skin. Rate of wound epithelialization and number of infected wounds were determined. Large reductions in numbers of cultured organisms were observed after treatment with Chlorazene. No differences in rate of wound healing could be determined in water- or Chlorazene-treated animals. Chlorazene-treated wounds contained fewer pseudomonas organisms than water-treated controls on postinoculation days five and six. These results confirm that Chlorazene is an effective water disinfectant. Data also indicate that in the concentration used, Chlorazene does not affect the rate of wound healing.

Removal of sodium inactivation and block of sodium channels by chloramine-T in crayfish and squid giant axons

Modification of sodium channels by chloramine-T was examined in voltage clamped internally perfused crayfish and squid giant axons using the double sucrose gap and axial wire technique, respectively. Freshly prepared chloramine-T solution exerted two major actions on sodium channels: (a) an irreversible removal of the fast Na inactivation, and (b) a reversible block of the Na current. Both effects were observed when chloramine-T was applied internally or externally (5-10 mM) to axons. The first effect was studied in crayfish axons. We found that the removal of the fast Na inactivation did not depend on the states of the channel since the channel could be modified by chloramine-T at holding potential (from -80 to -100 mV) or at depolarized potential of -30 mV. After removal of fast Na inactivation, the slow inactivation mechanism was still present, and more channels could undergo slow inactivation. This result indicates that in crayfish axons the transition through the fast inactivated state is not a prerequisite for the slow inactivation to occur. During chloramine-T treatment, a distinct blocking phase occurred, which recovered upon washing out the drug. This second effect of chloramine-T was studied in detail in squid axons. After 24 h, chloramine-T solution lost its ability to remove fast inactivation but retained its blocking action. After removal of the fast Na inactivation, both fresh and aged chloramine-T solutions blocked the Na currents with a similar potency and in a voltage-dependent manner, being more pronounced at lower depolarizing potentials. A similar voltage-dependent block was observed with aged chloramine-T solution in an axon with intact inactivation. In contrast to the action of the fresh solution, the aged chloramine-T solution was found to accelerate the decay of Na currents.These results suggest that chloramine-T solution contains at least two active molecular forms that act at different sites in the Na channel.

Kinetics of oxidation of ketoglutaric acids by alkaline chloramine-t solution

Kinetics of the oxidation of α-ketoglutaric and β-ketoglutaric acids by chloramine-T (CAT) have been investigated in highly alkaline media. The reactions show first order dependence in chloramine-T and fractional order in substrates. The order in hydroxide ions has been found to be second but shows a slight decrease at high concentration of alkali. No effect of p-toluene-sulphonamide was evident. Observed stoichiometry, positive effects of ionic strength and dielectric constant point to a mechanism involving formation of an intermediate in a termolecular rate determining slowest step among hypochlorite ion, hydroxide ion and enolic anion of keto acids followed by a fast step leading to products. Activation parameters have been computed and formaldehyde and formic acid were Identified as end-products.

Automated fluorometric amino acid analysis: The determination of nonprotein cyclic imino acids

The fluorometric detection of eight previously unstudied cyclic imino acids of plant origin following automated ion-exchange fractionation is reported. cis-4-Hydroxyproline, trans-4- and cis- and trans-5-hydroxypipecolic acids, acetylaminopipecolic acid, and 2,4- trans-4,5- rans- and 2,4- trans-4,5- cis-4,5,-dihydroxypipecolic acids are resolved with a pH 3.1 buffer. Pipecolic acid is subsequently eluted by increasing the pH to 3.5. Detection involves a post-column oxidation of the secondary amines by chloramine-T prior to the introduction of the fluorogenic agent o-phthalaldehyde. The characteristic optima each compound shows with respect to the pH of the chloramine-T solution, the concentration of chloramine-T, and the temperature at which the oxidation step is carried out are reported. The method establishes the usefulness of o-phthalaldehyde for the detection of non-protein amino acids in plant material.

Biological evaluation of root canal antiseptics using in vitro and in vivo methods.

Five antiseptics commonly used in endodontic treatment were evaluated with regard to cytotoxicity and initial tissue irritating effect. The cytotoxicity was evaluated in a cell culture system using HeLa cells and the initial tissue irritating effect was assessed by application of the antiseptics onto an intact nonepithelialized tissue surface. The cell response was assessed by registering changes in the DNA synthesis of the cells and the tissue response was assessed by registering changes in the oxidoreductase enzyme activity of the tissue. To evaluate the ability of the cells and the tissue to overcome an induced damage, one part of the study included a recovery period before the condition of the cells and the tissue was assessed. The most severe cell and tissue reactions were caused by 5% Chloramine-T whereas no differences in toxicity or tissue irritating effect were found between 0.04% Jodopax, 0.1% Biosept, 0.1% Hibitane, or 0.5% sodium hypochlorite. The HeLa cells showed the best recovery after having been influenced by Jodopax, Chloramine-T or sodium hypochlorite solutions, whereas the best tissue recovery was observed in the experiments with Biosept and Hibitane.