RESUMO

This review article explores the fundamental principles of modern endodontics with a focus on root canal cleaning and shaping. It reviews commonly used endodontic irrigant, namely sodium hypochlorite (NaOCl), herbal extracts, chlorhexidine (CHX), and chelating agents, highlighting their properties, applications, and potential drawbacks. NaOCl, a key antimicrobial agent, demonstrates effectiveness against various microorganisms but poses challenges such as high cytotoxicity. Herbal extracts, gaining recognition in endodontics, present an alternative with potential advantages in preserving dentin integrity. CHX, known for its broad-spectrum antimicrobial activity, is discussed in both liquid and gel formulations, emphasizing its role in reducing smear layer formation and preserving hybrid layer durability. Chelating agents, specifically ethylenediaminetetraacetic acid and citric acid, play a vital role in removing the smear layer, enhancing dentin permeability, and facilitating the penetration of antimicrobial agents. The review article underscores the importance of careful application and consideration of each irrigant's properties to ensure safe and effective endodontic procedures. It serves as a valuable guide for clinicians in selecting appropriate irrigants based on specific treatment requirements.

RESUMO

Ammonium and hexyltrimethylammonium thiomolybdates (ATM and ATM-C6) and thiotungstates (ATT and ATT-C6) were synthesized. Their toxicity was evaluated using both in vitro and in vivo approaches via the zebrafish embryo acute toxicity assay (ZFET), while the copper-thiometallate interaction was studied using cyclic voltammetry, as well as in an in vivo assay. Cyclic voltammetry suggests that all thiometallates form complexes with copper in a 2:1 Cu:thiometallate ratio. Both in vitro and in vivo assays demonstrated low toxicity in BALB/3T3 cells and in zebrafish embryos, with high IC50 and LC50 values. Furthermore, the hexyltrimethylammonium ion played a crucial role in enhancing viability and reducing toxicity during prolonged treatments for ATM and ATT. In particular, the ZEFT assay uncovered the accumulation of ATM in zebrafish yolk, averted by the incorporation of the hexyltrimethylammonium ion. Notably, the copper-thiometallate interaction assay highlighted the improved viability of embryos when cultured in CuCl2 and ATM-C6, even at high CuCl2 concentrations. The hatching assay further confirmed that copper-ATM-C6 interaction mitigates inhibitory effects induced by thiomolybdates and CuCl2 when administered individually. These results suggest that the incorporation of the hexyltrimethylammonium ion in ATM increase its ability to interact with copper and its potential application as a copper chelator.

Assuntos

RESUMO

This study investigated the purification of bromelain obtained from pineapple fruit using a new adsorbent for immobilized metal ion affinity chromatography (IMAC), with chlorophyll obtained from plant leaves as a chelating agent. The purification of bromelain was evaluated in batches from the crude extract of pineapple pulp (EXT), and the extract precipitated with 50 % ammonium sulfate (EXT.PR), the imidazole buffer (200 mM, pH 7.2) being analyzed and sodium acetate buffer, pH 5.0 + 1.0 NaCl as elution solutions. All methods tested could separate forms of bromelain with molecular weights between ±21 to 25 kDa. Although the technique using EXT.PR stood out in terms of purity, presenting a purification factor of around 3.09 ± 0.31 for elution with imidazole and 4.23 ± 0.12 for acetate buffer solution. In contrast, the EXT methods obtained values between 2.44 ± 0.23 and 3.21 ± 0.74 for elution with imidazole and acetate buffer, respectively, for purification from EXT.PR has lower yield values (around 5 %) than EXT (around 15 %). The number of steps tends to reduce yield and increase process costs, so the purification process in a monolithic bed coupled to the chromatographic system using the crude extract was evaluated. The final product obtained had a purification factor of 6, with a specific enzymatic activity of 59.61 ± 0.00 U·mg-1 and a yield of around 39 %, with only one band observed in the SDS-PAGE electrophoresis analysis, indicating that the matrix produced can separate specific proteins from the total fraction in the raw material. The IMAC matrix immobilized with chlorophyll proved promising and viable for application in protease purification processes.

Assuntos

RESUMO

Growing fish in a recirculating aquaculture system (RAS) involves various stress factors that directly affect their physiological condition. This study aimed to investigate the effect of a chelated organic-mineral additive including Fe, Mn, Cu, Zn, Co, Se and I; on the rearing performance of juvenilecatfish (Clariasgariepinus) under RAS conditions. Four groups of fish (n=50) were formed: a control group (receiving standard feed) and three experimental groups (receiving standard feed with biogenic elements chelate compounds in different concentrations). At the end of the experiment (30 days), the physiological condition of the fish was evaluated by the growth rate, internal organs condition, blood serum biochemical indices and histological examination of the middle intestine. The survival rate of fish in the experimental groups was 96-98%. According to the results, the absolute increase was 14,30% in group III, 11,13% in group II and 6,71% in group I, compared to the control. However, the use of chelated compounds in high concentrations can cause necrosis and erosion of the apical part of the villi (groups II and III). Blood biochemical analysis of fish (group II and III) receiving medium and high concentrations of chelated compounds showed high ALT activity, which was 23,02% (p<0,05) and 45,19% (p<0,05) higher compared to control, respectively. Mineral-chelate compounds, of the studied composition, at a concentration of 0,5 g/kg positively affect the histological structure of the midgut of Clarias gariepinus. This dosage of the investigated feed additive can be recommended for the practical application of rearing Clariasgariepinus in closed water installations.

Este estudo teve como objetivo investigar o efeito de um aditivo orgânico-mineral quelatado que inclui Fe, Mn, Cu, Zn, Co, Se e I sobre o desempenho de criação de juvenis de bagre-africano (Clarias gariepinus) em condições de RAS. Foram formados quatro grupos de peixes (n=50): um grupo controle (recebendo ração padrão) e três grupos experimentais (recebendo ração padrão com elementos biogênicos compostos quelatos em diferentes concentrações). Ao final do experimento (30 dias), a condição fisiológica dos peixes foi avaliada pela taxa de crescimento, condição dos órgãos internos, índices bioquímicos séricos sanguíneos e exame histológico do intestino médio. A taxa de sobrevivência dos peixes nos grupos experimentais foi de 96-98%. De acordo com os resultados, o aumento absoluto foi de 14,30% no grupo III, 11,13% no grupo II e 6,71% no grupo I, em relação ao controle. No entanto, o uso de compostos quelatados em altas concentrações pode causar necrose e erosão da parte apical das vilosidades (grupos II e III). A análise bioquímica do sangue de peixes (grupo II e III) que receberam concentrações médias e altas de compostos quelatados mostrou alta atividade de ALT, que foi 23,02% (p<0,05) e 45,19% (p<0,05) maior comparado ao controle, respectivamente. Compostos mineral-quelatos, da composição estudada, na concentração de 0,5 g/kg, afetam positivamente a estrutura histológica do intestino médio de Clarias gariepinus. Esta dosagem do aditivo alimentar investigado pode ser recomendada para a aplicação prática de criação de Clarias gariepinus em instalações de água fechadas.

Assuntos

RESUMO

OBJECTIVE: Generate recommendations for the diagnosis, management, and follow-up of chronic hyperkalemia. METHOD: This consensus was made by nephrologists and cardiologists following the GRADE methodology. RESULTS: Chronic hyperkalemia can be defined as a biochemical condition with or without clinical manifestations characterized by a recurrent elevation of serum potassium levels that may require pharmacological and or non-pharmacological intervention. It can be classified as mild (K+ 5.0 to < 5.5 mEq/L), moderate (K+ 5.5 to 6.0 mEq/L) or severe (K+ > 6.0 mEq/L). Its incidence and prevalence have yet to be determined. Risk factors: chronic kidney disease, chronic heart failure, diabetes mellitus, age ≥ 65 years, hypertension, and drugs that inhibit the renin angiotensin aldosterone system (RAASi), among others. There is no consensus for the management of chronic hyperkalemia. The suggested pattern for patients is to identify and eliminate or control risk factors, provide advice on potassium intake and, for whom it is indicated, optimize RAASi therapy, administer oral potassium binders and correct metabolic acidosis. CONCLUSIONS: The recommendation is to pay attention to the diagnosis, management, and follow-up of chronic hyperkalemia, especially in patients with risk factors.

OBJETIVO: Generar recomendaciones para el diagnóstico, el manejo y el seguimiento de la hiperkalemia crónica. MÉTODO: Este consenso fue realizado por nefrólogos y cardiólogos siguiendo la metodología GRADE. RESULTADOS: La hiperkalemia crónica puede definirse como una condición bioquímica, con o sin manifestaciones clínicas, caracterizada por una elevación recurrente de las concentraciones séricas de potasio que puede requerir una intervención farmacológica, no farmacológica o ambas. Puede clasificarse en leve (K+ 5,0 a < 5,5 mEq/l), moderada (K+ 5,5 a 6,0 mEq/l) o grave (K+ > 6,0 mEq/l). Su incidencia y prevalencia no han sido claramente determinadas. Se consideran factores de riesgo la enfermedad renal crónica, la insuficiencia cardiaca crónica, la diabetes mellitus, la edad ≥ 65 años, la hipertensión arterial y el tratamiento con inhibidores del sistema renina-angiotensina-aldosterona (iSRAA), entre otros. No hay consenso sobre el manejo de la hiperkalemia crónica. Se sugiere identificar y eliminar o controlar los factores de riesgo, brindar asesoramiento sobre la ingesta de potasio y, para quien esté indicado, optimizar la terapia con iSRAA, administrar aglutinantes orales del potasio y corregir la acidosis metabólica. CONCLUSIONES: Se recomienda prestar atención al diagnóstico, el manejo y el seguimiento de la hiperkalemia crónica, en especial en los pacientes con factores de riesgo.

Assuntos

RESUMO

Ultra-high temperature (UHT) treatments are of high economic relevance for food industries because they contribute to extending the shelf life of food products and facilitating their distribution. In the dairy segment, UHT treatments are applied to a wide range of products containing variable protein amounts. In this sense, the changes in the molecular structure of milk proteins induced by the severity of UHT treatments may lead to fouling in equipment during processing or sedimentation and/or gelation during storage. Nowadays, these concerns are even more relevant due to the increasing demand for UHT-treated high-protein beverages. This review will discuss the two main strategies used by industries to increase the stability of milk proteins during and/or after UHT treatments: (i) addition of chelating agents and (ii) use of polysaccharides. Moreover, the challenges and opportunities associated with promising strategies to improve the stability of milk proteins during and/or after UHT treatments will be covered in this review. The information compiled will be useful to guide researchers and industries in developing more stable UHT dairy products in harmony with consumers' demands.

RESUMO

We evaluate the effectiveness of chelating resins (CR) derived from Merrifield resin (MR) and 1,2-phenylenediamine (PDA), 2,2'-dipyridylamine (DPA), and 2-(aminomethyl)pyridine (AMP) as adsorbent dosimeters for Ag+, Cu2+, Fe3+, and Pb2+ cations from water under competitive and noncompetitive conditions. MR-PDA, MR-DPA, and MR-AMP were obtained in a 95-97% yield and characterized by IR, fluorescence, and SEM. The ability of CRs as adsorbents was determined by batch and flow procedures. MR-PDA showed a batch adsorption capacity order of Fe3+ (29.8 mg/g) > Ag+ (2.7 mg/g) > Pb2+ (2.6 mg/g) at pH 3.4. The flow adsorption showed affinity towards the Ag+ cation at pH 7 (18.4 mg/g) and a reusability of 10 cycles. In MR-DPA, the batch adsorption capacity order was Ag+ (9.1 mg/g) > Pb2+ (8.2 mg/g) > Cu2+ (3.5 mg/g) at pH 5. The flow adsorption showed affinity to the Cu2+ cation at pH 5 (2.2 mg/g) and a reuse of five cycles. In MR-AMP, the batch adsorption capacity was Ag+ (17.1 mg/g) at pH 3.4. The flow adsorption showed affinity to the Fe3+ cation at pH 2 (4.3 mg/g) and a reuse of three cycles. The three synthesized and reusable CRs have potential as adsorbents for Ag+, Cu2+, Fe3+, and Pb2+ cations and showed versatility in metal removal for water treatment.

RESUMO

Background: Despite all efforts, iron deficiency anemia remains a serious public health problem among Brazilian children. Objective: To evaluate dietary iron intake and dietary practices that interfere with the absorption of this nutrient from three regions of Brazil. Methods: Brazil Kids Nutrition and Health Study is a cross-sectional dietary intake study in children aged 4-13.9 years old designed to investigate nutrient intakes and gaps of Brazilian children in a representative sample of households from Northeast, Southeast and South regions. Nutrient intake was assessed based on multiple-pass 24-h dietary recall and U.S. National Cancer Institute method was used to estimate usual micronutrients intakes and compliance with Dietary Reference Intakes. Results: Five hundred sixteen individuals participated in the study (52.3% male). The top three most consumed food sources of iron were products of plant origin. Food sources of animal origin contributed with <20% of the total iron intake. Vitamin C intake was adequate, but the concomitant consumption of food sources of vitamin C with plant food sources of iron was not common. On the other hand, the concomitant intake of plant food sources of iron with food sources of iron chelators (e.g., coffee and teas) was frequent. Conclusions: Adequate iron intake was observed in all three regions in Brazil. Children's diet showed low iron bioavailability and insufficient consumption of food sources of iron absorption stimulants. Frequent presence of iron chelators and inhibitors of iron absorption might help to explain the high prevalence of iron deficiency in the country.

Assuntos

RESUMO

OBJECTIVE: To identify the effect of two chitosan solutions on the release of root dentin matrix proteins and to describe the chemical changes observed following conditioning with chelating agents. MATERIALS AND METHODS: The release of dentin sialoprotein (DSP), transforming growth factor-beta 1 (TGF-ß1), vascular endothelial growth factor (VEGF), and platelet-derived growth factor-BB (PDGF-BB) with different chelating agents, including ethylenediaminetetraacetic acid (EDTA), chitosan solution (CS), and nanoparticulate chitosan (CSnp), was investigated. DSP was quantified using an enzyme-linked immunosorbent assay (ELISA). TGF-ß1, VEGF, and PDGF-BB were quantified using a cytokine bead panel (CBA). Raman spectroscopy was performed to identify surface chemical changes. Statistical analysis was performed using Kruskal-Wallis test with Mann-Whitney-Wilcoxon rank-sum test (p < 0.05). RESULTS: TGF-ß1, VEGF, and DSP solubilized in all irrigants tested. CSnp showed the highest concentration of DSP. PDGF-BB did not exceed the detection limits. Raman spectroscopy revealed a decrease in the phosphate and carbonate peaks, representing the chelating effect of EDTA, CS, and CSnp. Additionally, CSnp showed the greatest preservation of the amide I and III content. CONCLUSION: Proteins can be released from dentin via EDTA, CS, and CSnp conditioning. Raman spectroscopic revealed changes in the inorganic content of the root dentin after chelation. Furthermore, use of CSnp facilitated a preservation of the organic content. CLINICAL RELEVANCE: Chelation allows the release of proteins, justifying the use of chelating agents in regenerative endodontics. The chitosan-dentin matrix interaction also promotes the protection of the organic content as an additional benefit to its protein releasing effect.

Assuntos

RESUMO

The aims of this study were to assess Cu, Zn, and Cr pollution in a highly polluted river in Argentina (Matanza-Riachuelo) and to evaluate tolerance strategies and toxic effects in aquatic macrophytes. Chemical techniques were used to assess the bioavailability of these metals and to evaluate their uptake and translocation by plants. The ultrastructure of the roots of a free-floating plant (Eichhornia crassipes) and the leaves of an emergent macrophyte (Sagittaria montevidensis) was examined using transmission electron microscopy. In the lower basin of the river, the highest concentrations of total heavy metals were detected in water (179 µgZn/g; 54 µgCu/g; 240 µgCr/g) and sediments (1499 µgZn/g; 393 µgCu/g; 4886 µgCr/g). In the upper basin of the river, low percentages of Zn and Cu (8 to 25%) were extracted with DTPA and EDTA, probably due to the lithogenic origin of these metals. Higher extraction percentages (24 to 66%) were obtained in the lower basin, in accordance with anthropogenic pollution. For Cr, extraction percentages were low in the upper basin of the river (< 4.5%) and extremely low in the lower basin (< 0.03%). In S. montevidensis, the BCF (bioconcentration factor) and TF (translocation factor) indexes were compatible with heavy metal exclusion mechanisms in sediments, whereas in the E. crassipes, root compartmentalization could be the main tolerance strategy. The leaves of S. montevidensis showed no evidence of damage, whereas ultrastructural alterations (plasmolyzed cells, disorganized membranes) were observed in E. crassipes.

Assuntos