Partial incision blunt scissors lamellar keratectomy under topical anesthesia for the treatment of presumed calcific corneal degeneration in dogs.

OBJECTIVE: The aim of the study was to investigate clinical features of lamellar keratectomy for presumed calcific corneal degeneration in a population of geriatric dogs using blunt scissors dissection under topical anesthesia. ANIMALS STUDIED AND PROCEDURES: Retrospective analysis of dogs with clinically diagnosed calcific degeneration treated by keratectomy under topical anesthesia between 2015 and 2021 at two veterinary ophthalmology practices was performed. Descriptive data regarding signalment, concurrent systemic and ocular disease, complications, healing time, and recurrence were collected. Kaplan-Meier survival analysis was performed to calculate 1-year recurrence probability. RESULTS: Sixty-five eyes in 57 dogs met inclusion criteria. All 54 eyes with follow-up healed within a median of 14 days (7-74), including 17 with complicating factors of infection or deep stromal ulceration. Globe rupture occurred intraoperatively in three eyes (4.6%), for which subsequent conjunctival graft was performed. Calculated 1-year recurrence probability from 47 eyes followed long term was 25%. Multivariate Cox proportional hazard modeling showed a significant association between documented systemic disease and time to recurrence (p = .035), irrespective of topical EDTA use (p = .432). Median follow-up time available for all cases was 249 days. CONCLUSIONS: Blunt lamellar dissection with corneal scissors can be performed in dogs under topical anesthesia, yielding healing times and recurrence comparable to previously reported treatments for calcific corneal degeneration. Globe rupture is an inherent risk of both the disease and procedure and occurred in 4.6% of treated eyes. This approach expands non-anesthetic treatment options for affected patients but should only be performed with advanced microsurgical training and client counseling on individual risk and benefit.

Ethylenediaminetetraacetic acid (EDTA) enhances cAMP production in human TDAG8-expressing cells.

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that binds tightly to metal ions. We found that cAMP response element (CRE)-driven promoter activity by protons was enhanced by EDTA in human T-cell death-associated gene 8 (TDAG8)-overexpressed HEK293T cells. The enhancing action by EDTA was also detected by proton-induced cAMP production that is located upstream from the CRE-driven promoter activity even at physiological proton concentration pH7.4. The proton-induced CRE-driven promoter activity was not enhanced by other chelating agents, ethylene glycol tetraacetic acid (EGTA) and sodium citrate. The enhanced CRE-driven promoter activity by EDTA was not attenuated by increasing the extracellular calcium ion concentration. These results indicate that the EDTA-enhancing action may not be due to its chelating action but might rather be another EDTA-specific effect. Enhanced cAMP production by EDTA was also detected in a human leukemia cell line HL-60, in which TDAG8 and OGR1 (ovarian cancer G-protein-coupled receptor 1) were endogenously expressed, suggesting that the medical use of EDTA would influence the physiological and pathophysiological functions of hematopoietic cells.

Effect of 24% EDTA root conditioning on the outcome of modified coronally advanced tunnel technique with subepithelial connective tissue graft for the treatment of multiple gingival recessions: a randomized clinical trial.

OBJECTIVES: To investigate effects of root conditioning with 24% ethylenediaminetetraacetic acid (EDTA) on the 12-month outcomes after treatment of multiple gingival recessions (GR) with modified coronally advanced tunnel (MCAT) and subepithelial connective tissue graft (SCTG). MATERIALS AND METHODS: Twenty patients with 142 GR were treated (72 test sites: SCTG + EDTA and 70 control sites: SCTG). Average and complete root coverage (ARC, CRC), gain in keratinized tissue width (KTW), gain in gingival thickness (GT), root esthetic coverage score (RES), and patient-reported outcome measures (PROMs) were evaluated at 12 months post-operatively. RESULTS: Differences between pre- and post-operative values were statistically significant only within but not between treatment modalities. At 12 months, ARC was 86.0% for SCTG + EDTA-treated and 84.6 for SCTG-treated defects (p = 0.6636). CRC was observed in 90.2% (tests) and 91.4% (controls) of all cases (p = 0.9903). Professional assessment of esthetic outcomes using RES showed highly positive results reaching the value of 8.9 in case of test sites and 8.7 for control sites (p = 0.3358). Severity of pain and swelling did not differ between sites, regardless of whether EDTA was used. CONCLUSIONS: Test and control sites presented similarly positive outcomes related to root coverage, periodontal and esthetic parameters, and patient satisfaction and self-reported morbidity with no statistical differences between them 12 months after surgery. No significant differences in evaluated variables were observed between sites treated with and without 24% EDTA. Clinical relevance Considering the limitations of the present study, the use of 24% EDTA for root conditioning did not improve 12-month outcomes after treatment of multiple RT1 and RT2 gingival recessions with MCAT and SCTG. Trial registration ClinicalTrials.gov identifier: NCT03354104.

Topical Ethylenediaminetetraacetic acid (EDTA) administration following corneal diamond burr keratotomy for calcareous corneal degeneration in canines.

OBJECTIVE: To evaluate the outcomes of canine patients diagnosed with corneal ulceration associated with presumed calcareous corneal degeneration (CCD) that were treated with diamond burr keratotomy (DBK) and ongoing postoperative topical 3% or 4% Ethylenediaminetetraacetic acid (EDTA). PROCEDURES: Retrospective assessment of CCD cases treated with ongoing topical EDTA following DBK between 2011 and 2020 at Veterinary Ophthalmic Referrals. Descriptive statistics of the study population were assessed, and a survival analysis was performed using R statistical software. RESULTS: A total of 51 eyes from 41 dogs were assessed, with small terrier breeds overrepresented (27/41, 65.9%). Median age of dogs at the time of diagnosis was 14.3 years (range 8-17.2 years). Following DBK, the median time to commencement of topical EDTA was 11 days (range 0-28 days). Cases were followed for a median duration of 216 days (range 42-1379 days). Corneal ulceration recurred in 7/51 (13.7%) eyes at a median duration of 80 days (range 63-156 days). The probability of recurrence of corneal ulceration associated with CCD at 12 months was 15.6% (95% CI: 4.1-25.7%). A second DBK procedure followed by ongoing topical EDTA was performed in 4/7 (57.1%) of the recurred eyes. These retreated eyes had no further recurrence recorded and a median follow-up time of 401 days (range 120-858 days). CONCLUSION: Ongoing topical EDTA following DBK is an effective adjunct treatment method for CCD with reduced rates of recurrence of CCD-associated corneal ulceration when compared to published rates of recurrence when treated with DBK alone.

Comparative evaluation of two chelating agents in collagen fiber network modification over dentinal tubules: An in vitro analysis.

OBJECTIVE: To compare effectiveness of ethylenediaminetetraacetic acid (EDTA) and citric acid in removing collagen fiber network covering dentinal tubules of human teeth. MATERIALS AND METHODS: Eighteen dentin discs were divided in three groups; Gp 1: discs received no treatment (control), Gp 2: discs etched with 17% EDTA (pH = 7.1), and Gp 3: discs etched with 6 wt% citric acid (pH = 4.0). Scanning electron microscopy (SEM) was performed to assess collagen fiber removal and X-ray diffraction (XRD) was implemented to analyse crystal peaks of discs. RESULTS: The SEM analysis demonstrated more collagen removal with EDTA treatment compared to citric acid treated specimens. Grade 6 (81% to 100% fiber removal) was mostly achieved for Gp 2 samples whereas grade 2 (1% to 20% fiber removal) was mostly achieved for Gp 3 samples and inter-group comparisons between these groups were statistically significant (p < 0.05). X-ray diffractogram of control and experimental samples demonstrated absence of calcite phase in experimental groups. The change in peak shapes and intensities were observed and citric acid treated samples revealed more intense peaks than EDTA group. CONCLUSION: Our study found 17% EDTA to be more effective in removing collagen fibers when matched with 6% citric acid.

Effect of EDTA root conditioning on the outcome of coronally advanced flap with connective tissue graft: a systematic review and meta-analysis.

OBJECTIVES: CAF in combination with a connective tissue graft (CTG) is considered the technique of choice for treating gingival recessions (GRs). Among the many recognized factors that can affect the outcomes, the use of chemical agents has been proposed. The effect of EDTA, as a commonly used agent, remains controversial. Therefore, the aim of this review was to assess the efficacy of EDTA root conditioning when combined to CAF + CTG. MATERIAL AND METHODS: A literature search was conducted to identify randomized clinical trials (RCTs) that performed CAF + CTG with and without EDTA for root coverage procedures. The following outcomes were assessed: recession reduction (Rec Red), complete root coverage (CRC), keratinized tissue gain (KT gain), clinical attachment level changes (CAL gain), and changes in pocket depth (PD changes). RESULTS: Fourteen RCTs (575 GRs) were included and analyzed. Six articles were included in the EDTA group, with 8 in the non-EDTA group. Meta-analyses revealed statistically significant differences for the outcomes of Rec Red (3.68 mm versus 3.07 mm), CAL gain (4.15 mm versus 3.07 mm), and PD changes (- 0.44 mm versus 0.27 mm) in favor of the EDTA group, while outcomes of CRC (odds ratio of 1.15) and KT gain (1.98 mm versus 1.62 mm) were not significantly different. CONCLUSIONS: Limited evidence is available when evaluating the effectiveness of EDTA root conditioning with CAF + CTG. However, the adjunct application of EDTA with CAF + CTG appears to be beneficial. CLINICAL RELEVANCE: The adjunct application of EDTA may provide benefits when performing root coverage procedure via CAF + CTG.

Sealing ability of various endodontic sealers with or without ethylenediaminetetraacetic acid (EDTA) treatment on bovine root canal.

This study investigated the wettability and consistency of various endodontic sealers, both inorganic and organic, and evaluated their sealing ability of root canals using the single-cone obturation technique, with and without ethylenediaminetetraacetic acid (EDTA) treatment. Bovine root canals were endodontically prepared and filled in preparation for the dye penetration test with toluidine blue solution. All sealers exhibited contact angles similar to or lower than dentin and displayed superior consistency. Among the sealers, organic sealers used without EDTA treatment showed reduced dye penetration compared to inorganic sealers. However, some inorganic and organic sealers showed dye penetration in the sealer and dentin of root canals subjected to EDTA treatment. In conclusion, the single-cone obturation technique, combined with these endodontic sealers, achieved close contact with root canal dentin due to their wettability and consistency. However, the sealing ability of certain sealers was influenced by EDTA treatment.

Comparison of Tetrasodium EDTA 4% with Sodium Citrate 4% as Line-Locking Solutions at 2 Tertiary Hemodialysis Centres.

Background: The patency of central venous catheters (CVCs) in patients undergoing hemodialysis (HD) is maintained by instilling sodium citrate 4% (SC 4%) locking solution. Alteplase, a thrombolytic agent, is administered to restore function if patency is lost. Objective: To compare SC 4% with a new line-locking solution, ethylenediaminetetraacetic acid 4% (EDTA 4%), in terms of CVC patency and alteplase use. Methods: This retrospective chart review included all HD patients who were switched from SC 4% to EDTA 4% locking solution at 2 tertiary HD centres between June and December 2021. Patients were switched to EDTA 4% if they had high usage of alteplase (receiving ≥ 2 doses of alteplase in a 2-week period). For each line-locking agent, HD pump speeds and alteplase use were analyzed over 2 consecutive 12-week periods. Mean serum calcium and ionized calcium values were recorded during each period. A cost analysis was also performed. Results: A total of 37 HD patients were switched to EDTA 4% during the study period. There was no difference in mean HD pump speed between SC 4% and EDTA 4% (307.7 vs 305.1 mL/min, p = 0.48). The number of catheter-use-days on which alteplase was required declined significantly, from 313 days with SC 4% to 94 days with EDTA 4% (p < 0.001), with an overall cost reduction of 34% ($13 183.21). The decrease in alteplase usage was primarily driven by 1 of the 2 sites. A statistically significant decrease in mean ionized calcium at site 2 (from 1.12 to 1.1 mmol/L, p = 0.037) was noted. As well, an intraluminal interaction between EDTA 4% and serum calcium caused 6 cases of low serum calcium. Conclusions: This study showed that use of EDTA 4% as a line-locking agent reduced alteplase usage in the CVCs of HD patients while maintaining adequate pump speed (i.e., ≥ 300 mL/min).

Contexte: La perméabilité des cathéters veineux centraux (CVC) chez les patients hémodialysés (HD) est maintenue en instillant une solution de verrouillage de citrate de sodium à 4 % (CS 4 %). L'alteplase, un agent thrombolytique, est administré pour rétablir la fonction en cas de perte de perméabilité. Objectif: Comparer la solution de CS 4 % et une nouvelle solution de verrouillage, l'acide éthylènediaminetétraacétique 4 % (EDTA 4 %), en termes de perméabilité du CVC et d'utilisation de l'alteplase. Méthodes: Cet examen rétrospectif des dossiers a été réalisé pour tous les patients HD qui sont passés de la solution de verrouillage de CS 4 % à la solution d'EDTA 4 % dans 2 centres d'hémodialyse tertiaires au cours de la période de juin à décembre 2021. Les patients sont passés à l'EDTA 4 % en cas d'utilisation élevée de l'alteplase (≥ 2 doses d'alteplase reçues sur une période de 2 semaines). Pour chaque agent de verrouillage, les vitesses de la pompe d'hémodialyse et l'utilisation de l'alteplase ont été analysées sur 2 périodes consécutives de 12 semaines. Les valeurs moyennes de calcium sérique et de calcium ionisé ont été enregistrées au cours de chaque période. Une analyse des coûts a également été réalisée. Résultats: Au total, 37 patients HD sont passés à l'EDTA 4 % au cours de la période de l'étude. Aucune différence dans la vitesse moyenne de la pompe d'hémodialyse n'a été constatée en cas d'utilisation de la solution de CS 4 % ou d'EDTA 4 % (307,7 c. 305,1 mL/min, p = 0,48). Le nombre de jours d'utilisation du cathéter qui ont nécessité l'utilisation de l'alteplase a diminué de manière significative, passant de 313 jours avec la solution de CS 4 % à 94 jours avec l'EDTA 4 % (p < 0,001); la réduction globale des coûts se montait à 34 % (économies de 13 183,21 $). L'utilisation moins importante de l'alteplase était principalement due à 1 des 2 sites. Une diminution significative du calcium ionisé moyen (1,12 c. 1,1 mmol/L, p = 0,037) a été observée au deuxième site. De plus, une interaction intraluminale entre l'EDTA 4 % et le calcium sérique a provoqué 6 cas d'hypocalcémie. Conclusions: Cette étude a montré que l'utilisation de l'EDTA 4 % comme agent de verrouillage réduisait l'utilisation de l'alteplase dans les CVC des patients HD tout en maintenant une vitesse de pompe adéquate (c'est-à-dire ≥ 300 mL/min).

A Universally EDTA-Assisted Synthesis of Polytypic Bismuth Telluride Nanoplates with a Size-Dependent Enhancement of Tumor Radiosensitivity and Metabolism In Vivo.

Bismuth telluride (Bi2Te3) is an available thermoelectric material with the lowest band gap among bismuth chalcogenides, revealing a broad application in photocatalysis. Unfortunately, its size and morphology related to a radio-catalysis property have rarely been explored. Herein, an ethylenediaminetetraacetic acid (EDTA)-assisted hydrothermal strategy was introduced to synthesize polytypic Bi2Te3 nanoplates (BT NPs) that exhibit size-dependent radio-sensitization and metabolism characteristics in vivo. By simply varying the molar ratio of EDTA/Bi3+ during the reaction, BT NPs with different sizes and morphologies were obtained. EDTA acting as chelating agent and "capping" agent contributed to the homogeneous growth of BT NPs by eliminating dangling bonds and reducing the surface energy of different facets. Further analyzing the size-dependent radio-sensitization mechanism, larger-sized BT NPs generated holes that preferentially catalyzed the conversion of OH- to ·OH when irradiated with X-rays, while the smaller-sized BT NPs exhibited faster decay kinetics producing higher 1O2 levels to enhance radiotherapy effects. A metabolomic analysis revealed that larger-sized BT NPs were oxidized into Bi(Ox) in the liver via a citrate cycle pathway, whereas smaller-sized BT NPs accumulated in the kidney and were excreted in urine in the form of ions by regulating the metabolism of glutamate. In a cervical cancer model, BT NPs combined with X-ray irradiation significantly antagonized tumor suppression through the promotion of apoptosis in tumor cells. Consequently, in addition to providing a prospect of BT NPs as an efficient radio-sensitizer to boost the tumor radiosensitivity, we put forth a strategy that can be universally applied in synthesizing metal chalcogenides for catalysis-promoted radiotherapy.

Effect of Root Surface Biomodification on Multiple Recession Coverage with Modified Coronally Advanced Tunnel Technique and Subepithelial Connective Tissue Graft: A Retrospective Analysis.

To improve treatment efficacy of gingival recessions (GR), chemical preparation of the exposed root surface was advocated. The aim of this study was to compare the additional influence of root biomodifications with 24% ethylenediaminetetraacetic acid (EDTA) alone or with enamel matrix derivative (EMD) on the 12 month outcomes of modified coronally advanced tunnel (MCAT) with subepithelial connective tissue graft in the treatment of multiple GR. Average root coverage (ARC), complete root coverage (CRC), reduction in GR, reduction in recession width (RW), gain in clinical attachment level (CAL), increase in gingival thickness (GT), increase in keratinized tissue width (KTW) and changes in root coverage esthetic score (RES) were evaluated. A total of 60 patients with 215 GR were enrolled. In 70, GR root surfaces were treated with EDTA + EMD, in other 72, with EDTA, while in the remaining 73 saline solution was applied. ARC was 94%, 89%, and 91% in the EDTA + EMD, the EDTA and the saline groups, respectively (p = 0.8871). Gains in clinical attachment level (CAL; 2.1 ± 1.1 mm) and RES values (9.6 ± 0.9) were significantly higher in the EDTA + EMD group, when compared with two other groups. The differences between other preoperative and postoperative parameters showed statistical significance only within but not between groups. MCAT outcomes may benefit from adjunctive use of EDTA + EMD regarding 12 month CAL gain and professionally assessed esthetics using RES following treatment of GR.

Exogenous methyl jasmonate enhances phytochemicals and delays senescence in harvested strawberries by modulating GABA shunt pathway.

In order to illustrate the relationship between methyl jasmonate (MeJA) and gamma aminobutyric acid (GABA) in maintaining the quality and improving the postharvest life of strawberry fruit, the harvested fruit were treated with MeJA for 16 h at 20 °C and stored at 3 ± 0.5 °C for 12 days. MeJA enhanced the expression levels of GABA shunt pathway-related genes, including glutamate decarboxylase, GABA transaminase, and succinic semialdehyde dehydrogenase, leading to an increase in GABA accumulation. Treated fruit showed higher levels of total acids, anthocyanins, total phenolics, antioxidants, and phenylalanine ammonia-lyase activity, and lower levels of cell membrane deterioration, total soluble solids, polyphenol oxidase activity and decay incidence rate. The results suggest that the positive effects of MeJA in extending the fruit postharvest life, enhancing phytochemical compounds, and decreasing the decay incidence rate may be due to the effects on motivating GABA shunt pathway and PAL enzyme activity.

Visual impairment induced by prosthetic cobaltism.

The case of a 68-year-old patient with visual loss secondary to prosthetic cobaltism is reported. The degeneration of the metallic hip prosthesis can produce a systemic absorption of cobalt with cardiac, neurological, endocrine, auditory, and visual manifestations. The diagnostic suspicion is confirmed by serum cobalt measurements. Treatment with early surgery and chelating agents can lead to improvement of the visual, and the other disorders.

Identification and characterization of a polyurethanase with lipase activity from Serratia liquefaciens isolated from cold raw cow's milk.

Lipases are associated with food spoilage and are also used in various biotechnological applications. In this study, we sought to purify, identify, and characterize a lipase from S. liquefaciens isolated from cold raw cow's milk. The lipase partially purified by ultrafiltration and gel filtration showed a specific activity of 2793 U/mg. By zymography, the enzyme presented approximately 65 kDa, and LC-MS/MS allowed the identification of a polyurethanase with a conserved domain of family I.3 lipase. The modeled and validated structure of polyurethanase was able to bind to different fatty acids and urethane by molecular docking. The polyurethanase showed optimum activity at pH 8.0 and 30 °C. In the presence of ions, activity was decreased, except for Ca2+, Mg2+, and Ba2+. Reducing agents did not alter the activity, while amino acid modifiers reduced enzyme activity. It is concluded that polyurethanase with lipase activity represents a potential enzyme for the deterioration of milk and dairy products, as well as a candidate for industrial applications.

Application of the Chromosome Image Analyzing System (CHIAS) for Straightening Cation-treated Bent Chromosomes.

Divalent cations, mainly calcium and magnesium ions, are known to play a major role in the maintenance of chromosomes. The depletion of both ions using ethylenediaminetetraacetic acid (EDTA) results in a bent chromosome structure with extended arms and dispersed chromatin fibers. The importance of divalent cations for the maintenance of chromosome structure has been reported previously; nevertheless, previous studies were limited to qualitative data only. Straightening the bent image of the chromosome would provide quantitative data. Thus, this study aimed to evaluate the effects of cation depletion by the application of the Chromosome Image Analyzing System (CHIAS) to straighten bent chromosomes. Human HeLa chromosomes were treated with EDTA as a known chelating agent in order to investigate the importance of divalent cations on the maintenance of chromosome structure. Chromosomes were stained and directly observed with a fluorescence microscope. Images were then analyzed using CHIAS. The results revealed that EDTA-treated chromosomes showed longer arms than those without EDTA treatment, and most of them tended to bend-out. By straightening the image using CHIAS, the bent chromosomes were successfully straightened. The average lengths of the chromosomes treated with and without EDTA were 4.97 and 0.96 µm, respectively. These results signify the advantages of CHIAS for chromosome analysis and highlight the fundamental effects of cations on chromosome condensation.

Effects of low frequency magnetic field on myoglobin oxidation stability.

The effects of low frequency magnetic field on myoglobin (Mb) oxidation stability were evaluated by treatments at 0, 3, 6, 9, 12 mT and storage for 10 h. The results showed that Mb oxidation was inhibited under all magnetic field treatments, due to the increase of total sulfhydryl and free amino groups (9 or 12 mT) from unfolding of Mb clusters (3, 9, 12 mT) as well as ß-turn and ß-sheet structures (9 or 12 mT). The unfolding also induced (i) the destruction or burial of iron porphyrin and tyrosine residues; (ii) the exposure of tryptophan; (iii) more uniform Mb particle size distribution (3, 9, 12 mT) and increased zeta potential (3, 6, 12 mT). Overall, magnetic field promoted exposed active groups as the preferred oxidation target, thus decreasing the oxidation rate of central iron atoms. It also promoted Mb stability by redistributing particle size and increasing zeta potential.

EFFECT OF INDOLE-3-ACETIC ACID, KINETIN, AND ETHYLENEDIAMINETETRAACETIC ACID ON PLANT GROWTH AND UPTAKE AND TRANSLOCATION OF LEAD, MICRONUTRIENTS, AND MACRONUTRIENTS IN ALFALFA PLANTS.

Alfalfa plants germinated and grown for 15 d in soil containing 80 mg Pb kg-1 were treated with ethylenediaminetetraacetic acid (EDTA) at 0.8 mM and indole-3-acetic acid-kinetin (IAA-KN) at 100 µM. Fifteen days after the treatment application, the concentration of lead (Pb), macronutrients, and micronutrients was determined using inductively coupled plasma/optical emission spectroscopy. The chlorophyll content and plant growth were also measured. Roots of plants exposed to Pb alone, Pb-EDTA, and Pb-EDTA-IAA-KN had 160, 140, and 150 mg Pb kg-1 DW, respectively. Pb was not detected in the stems of plants exposed to Pb alone; however, stems of plants treated with EDTA and EDTA-IAA-KN had 78 and 142 mg Pb kg-1 DW, respectively. While the Pb concentration in leaves of plants treated with EDTA and EDTA-IAA-KN was 92 and 127 mg kg-1 DW, respectively. In addition, EDTA and EDTA-IAA-KN significantly increased the translocation of zinc and manganese to leaves. The x-ray absorption spectroscopic studies demonstrated that Pb(II) was transported from roots to leaves without a change in the oxidation state.

Edetate Disodium-based Treatment in a Woman with Diabetes and Critical Limb Ischemia Scheduled for Lower Extremity Amputation.

Historically, it is underappreciated that women undergoing amputation for critical limb ischemia (CLI) are older, more severely ill, and have a poorer prognosis than men. Epidemiological studies have shown an association between environmentally acquired vasculotoxic metals, coronary events, and peripheral artery disease. In this paper, we describe an elderly woman with CLI referred for primary amputation underwent edetate disodium-based treatment, known to reduce toxic metal burden, as a final option for limb salvage.

Smear Layer Removal and Microhardness Alteration Potential of a Naturally Occurring Antioxidant - An In Vitro Study.

INTRODUCTION: It is well-known in the field of endodontics that the presence of a smear layer in the root canals can harbor bacteria and limit the penetration of irrigating solutions and intracanal medications into the dentinal tubules which, in turn, causes the failure of endodontic treatment. Removing the entire smear layer throughout the root canal is essential for the success of endodontic treatment and these chemical agents that facilitate the removal of the smear layer are called chelating agents. Ethylenediaminetetraacetic acid (EDTA), being the most widely used chelating agent, brings about increased reduction in the microhardness of the root dentin, thereby making it friable. N-acetyl cysteine (NAC) is naturally occurring antioxidant that has various beneficial properties for the human being. Several studies have been done in determining the antimicrobial efficacy of NAC against various endodontic pathogens and concluded NAC to be advantageous. The chelating property of NAC has been utilized in heavy metal detoxification, where it binds to the metal ion and removes them from the human system. However, this chelating property has not been explored in the field of endodontics. AIM: This study was aimed to compare the ability of N-acetyl cysteine with the conventional chelating agent in the removal of the smear layer and in altering the microhardness of root dentin. MATERIALS AND METHODOLOGY: A total of 84 single-rooted human mandibular premolars with relatively similar dimension and morphology, freshly extracted with closed apices, were collected from adult patients. The crowns of all specimens were cut transversally at the cementoenamel junction (CEJ) with the double-faced diamond disc at low speed, with water coolant, to obtain a 12 mm root length. The root canals were randomly divided into three equal groups according to the final irrigation solutions: Group I: 17% EDTA, Group II: 20% NAC, and Group III: distilled water (control). They were then randomly divided into two parts: scanning electron microscope (SEM) analysis for the extent of smear layer removal and microhardness evaluation using the Vicker's hardness test. RESULTS: The smear layer removal ability of EDTA and NAC were more effective in the coronal and middle thirds of the root canal. However, both groups showed less smear layer removal in the apical region. Specimens treated with distilled water showed the least reduction in the smear layer throughout the length of the root canals. Regarding the evaluation of microhardness, both EDTA and NAC had a significant reduction in root dentin microhardness. However, the percentage of dentin microhardness reduction was significantly more in the EDTA group (p < 0.05) than N-acetyl cysteine in the coronal, middle, and apical third of the root canals. CONCLUSION: The chelating property of NAC is equally effective to that of EDTA in the smear layer from the root canal, and it induced a significantly lesser reduction in microhardness of root dentin than EDTA.

Effect of ethylenediaminetetraacetic acid and biochar on Cu accumulation and subcellular partitioning in Amaranthus retroflexus L.

Phytoremediation combined with amendments and stabilization technologies are two crucial methods to deal with soil contaminated with heavy metals. Copper (Cu) contamination in soil near Cu mines poses a serious threat to ecosystems and human health. This study investigated the effect of ethylenediaminetetraacetic acid (EDTA) and biochar (BC) on the accumulation and subcellular distribution of Cu in Amaranthus retroflexus L. to demonstrate the remediation mechanism of EDTA and BC at the cellular level. The role of calcium (Ca) in response to Cu stress in A. retroflexus was also elucidated. We designed a pot experiment with a randomized block of four Cu levels (0, 100, 200, 400 mg kg-1) and three treatments (control, amendment with EDTA, and amendment with BC). The subcellular components were divided into three parts (cell walls, organelles, and soluble fraction) by differential centrifugation. The results showed that EDTA amendment significantly increased (p < 0.05) the concentrations of Cu in root cell walls and all subcellular components of stems and leaves (cell walls, organelles, and the soluble fraction). EDTA amendment significantly increased (p < 0.05) the proportion of exchangeable fraction and carbonate fraction in the soil. While BC amendment significantly decreased (p < 0.05) the concentrations of Cu in root cell walls and the root soluble fraction, it had no significant effects on Cu concentrations in the subcellular components of stems and leaves. The results revealed that EDTA mainly promoted the transfer of Cu to aboveground parts and accumulation in subcellular components of stems and leaves, while BC mainly limited Cu accumulation in root cell walls and the root soluble fraction. Ca concentrations in cell walls of roots, stems, and leaves increased as the Cu stress increased in all treatment groups, indicating that Ca plays an important role in relieving Cu toxicity in Amaranthus retroflexus L.

EDTA-Functionalized Covalent Organic Framework for the Removal of Heavy-Metal Ions.

The removal of heavy-metal ions from wastewater has drawn intense attention, because of their toxicity, bioaccumulation tendency, and persistency in nature. Adsorption is regarded as one of the most promising methods, because of its simplicity and efficiency. In the present work, we report the preparation of a novel EDTA-functionalized covalent organic framework (COF) for the removal of heavy-metal ions. First, a COF named TpPa-NO2 was reduced to TpPa-NH2 by using Na2S2O4 as a reductant, and then EDTA dianhydride was grafted onto TpPa-NH2 to obtain TpPa-NH2@EDTA through post-modification. Both the COF morphology and structure remained unchanged after post-modification. The TpPa-NH2@EDTA showed excellent performance in adsorbing different types of heavy-metal ions, such as soft Lewis acid (Ag+, Pd2+), hard Lewis acid (Fe3+, Cr3+), and borderline Lewis acid (Cu2+, Ni2+), and the removal efficiencies are all >85% within 5 min, because of the strong chelation effect of EDTA. The TpPa-NH2@EDTA also showed high adsorption ability in a pH ≥3 environment and have an adsorption capacity of >50 mg/g for the six representative heavy-metal ions. This work provides a new idea for the application of COF materials in the removal of heavy-metal ions from wastewater.