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1.
Am J Dent ; 33(5): 277-284, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33017532

RESUMO

PURPOSE: To investigate whether the addition of sodium-DNA (Na-DNA) to chlorhexidine (CHX)-containing mouthwash influenced morphology and viability of a reconstituted human oral epithelium (ROE), and protects ROE against oxidative stress. METHODS: Multi-layered 0.5 cm² ROE specimens were positioned inside a continuous flow bioreactor and grown air-lifted for 24 hours. They were treated with phosphate-buffered saline (PBS) (n= 16) or 1 vol% H2O2 for 1 minute (n= 16). Then, they were treated for 5 (n= 8) or 30 minutes (n= 8) with the experimental mouthwash solutions containing: 0.2 wt% CHX, 0.2 wt% CHX + 0.2 wt% Na-DNA, 0.2 wt% Na-DNA, PBS. After 60 minutes washout specimens were subjected to tetrazolium-based viability assay (MTT) confocal laser-scanning microscopy (CLSM), and histological evaluation using optical microscopy and transmission electron microscopy (TEM). RESULTS: ROE treated with Na-DNA for 30 minutes revealed significantly higher viability than PBS, and CHX + Na-DNA showed higher viability after 30-minute treatment than after 5 minutes, suggesting a significant protective activity of Na-DNA. Moreover, the protective effect of Na-DNA on cell viability was higher after the induction of oxidative stress. After treatment with CHX, CLSM revealed cell stress, leading to cell death in the outer layer. On the contrary, specimens treated with Na-DNA showed a much lower number of dead cells compared to PBS, both in the absence or presence of oxidative stress. Histological examination showed that the protective action of Na-DNA formulations reached more in-depth into the epithelium exposed to oxidative stress, due to intercellular spaces opening in the outer epithelium layers, giving way to Na-DNA to the inner parts of the epithelium. It can be concluded that Na-DNA had a topical protective activity when applied for 30 minutes unless the epithelium barrier is damaged, allowing it to act more in-depth. CLINICAL SIGNIFICANCE: Na-DNA showed a clear and protective action against cellular degeneration due to oxidative stress and, partly, to the exposure to CHX. Its addition to chlorhexidine mouthwash or gels could be clinically helpful in contrasting the detrimental activity of CHX on oral tissues, and in the preservation of cell viability, control of inflammation and wound healing.


Assuntos
Peróxido de Hidrogênio , Antissépticos Bucais/farmacologia , Antissépticos Bucais/toxicidade , Reatores Biológicos , DNA , Humanos , Sódio
2.
Chemosphere ; 254: 126916, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957301

RESUMO

4-Nonylphenol (4-NP), a phenolic endocrine disruptor chemical (EDC), is known to have high toxicity to aquatic organisms and humans. The remediation of 4-NP-contaminated marine sediments was studied using red algae-based biochar (RAB) thermochemically synthesized from Agardhiella subulata with simple pyrolysis process under different temperatures of 300-900 °C in CO2 atmosphere. The RAB was characterized by XRD, Raman, FTIR spectroscopy, and zeta potential measurements. The calcium in RAB efficiently activated sodium percarbonate (SPC) to generate reactive radicals for the catalytic degradation of 4-NP at pH 9.0. The oxygen-containing functional groups reacted with H2O2, which increased the generation of reactive radicals under alkaline pH condition. Ca2+ ion was the active species responsible for 4-NP degradation. CaO/CaCO3 on RAB surface enhanced direct electron transfer, increased HO production, and 4-NP degradation in marine sediments. Langmuir‒Hinshelwood type kinetics well described the 4-NP degradation process. Remediation of contaminated sediments using RAB could be a sustainable approach toward closed-loop biomass cycling in the degradation of 4-NP contaminants.


Assuntos
Carvão Vegetal/química , Disruptores Endócrinos/análise , Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Fenóis/análise , Rodófitas/química , Poluentes Químicos da Água/análise , Biomassa , Carbonatos/química , Catálise , Humanos , Peróxido de Hidrogênio/química , Cinética
3.
J Oral Sci ; 62(4): 458-460, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32863316

RESUMO

The purpose of this case report is to describe a minimally invasive technique for non-vital tooth bleaching using traditional Japanese paper, known as washi. Non-vital tooth bleaching with a mixture of sodium perborate and 30% hydrogen peroxide rolled in Japanese paper for a traumatically injured tooth, and in-office vital-tooth bleaching for the upper front six teeth and first premolars, were performed. Five-year follow-up showed satisfactory stability in the bleaching effects and did not show any problems in the traumatically injured tooth. The use of Japanese paper for non-vital tooth bleaching may minimize damage to discolored non-vital teeth.


Assuntos
Clareamento Dental , Descoloração de Dente , Dente não Vital , Dente Pré-Molar , Humanos , Peróxido de Hidrogênio , Japão
4.
Sci Total Environ ; 741: 140502, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32887006

RESUMO

Landfill leachate contains high concentrations of complex organic matter (OM) that can severely impact the ecological environment. If landfill leachate is to be treated using a combined "biological + advanced treatment" process, the molecular information of OM must be investigated to optimize the operation parameters of the combined process and maximize the removal of organic pollutants. This study applied ultra-high resolution mass spectroscopy to investigate the degradation and transformation characteristics of refractory OM in mature landfill leachate at the molecular level (m/z = 150-800) during biological treatment (i.e., semi-aerobic aged refuse biofilter, SAARB) and subsequent chemical oxidation (i.e., the Fenton process and ozonation). After SAARB treatment, the polycyclic aromatics (aromatic index, AI > 0.66) and polyphenol (0.66 ≥ AI > 0.50) contents increased, and the highly unsaturated phenolic compounds (AI ≤ 0.50 and H/C < 1.5), which have a high bioavailability, were mostly removed. Compared with raw leachate, SAARB effluent (i.e., SAARB leachate) contained fewer organics with short carbon chains, more organics with long carbon chains, an elevated condensation degree for organics and, thus, a considerably reduced biodegradability. Although both the Fenton and ozonation processes could remove many of the polycyclic aromatics and polyphenols, ozone produced considerable amounts of aliphatic compounds with high bioavailability. Compared to ozonation, the Fenton process utilized the hydroxyl radical to non-selectively react with OM and produced better mineralization results.


Assuntos
Resíduos de Alimentos , Ozônio , Eliminação de Resíduos , Poluentes Químicos da Água/análise , Peróxido de Hidrogênio , Oxirredução
5.
Ecotoxicol Environ Saf ; 203: 110974, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888622

RESUMO

Ammonia (NH3), an environmental pollutant, poses a serious threat to human and avian health. Although previous studies have showed that NH3 caused kidney injury, the molecular mechanisms of nephrotoxicity induced by NH3 remain unclear. To explore the mechanisms of NH3 nephrotoxicity, a total of 36 broiler chicks at one day of age were exposed to NH3. After 42 days of exposure, blood samples were collected to determine creatinine and uric acid; and kidney samples were weighted and then collected to detect ultrastructural changes, oxidative stress parameters, ATPases, necroptosis- and mitochondrial dynamics-related genes. The results showed that chickens exposed to NH3 showed lower relative kidney weight and an increase concentration in serum creatinine and uric acid. NH3 exposure caused nephrocyte necrosis and increased the expression of necroptosis-related genes (TNF-α, RIPK1, RIPK3, MLKL, and JNK). Besides, the activities of antioxidant systems (SOD, CAT, GSH-Px, and T-AOC) were reduced, whereas the concentrations of H2O2 and MDA were elevated. Lower activities of ATPases were obtained in NH3 treatment groups. Furthermore, the mitochondrial fission-related genes drp1 and mff were activated, and mitochondrial fusion-related genes opa1, mfn1 and mfn2 were suppressed after NH3 exposure. Based on the above results, we conclude that NH3 caused-oxidative stress and mitochondrial dysfunction mediated nephrocyte necroptosis in chickens. This study may provide new insight into NH3 nephrotoxicity.


Assuntos
Amônia/toxicidade , Poluentes Ambientais/toxicidade , Rim/efeitos dos fármacos , Dinâmica Mitocondrial/efeitos dos fármacos , Necroptose/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Galinhas , Expressão Gênica/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/metabolismo , Rim/ultraestrutura , Testes de Função Renal , Dinâmica Mitocondrial/genética , Tamanho do Órgão/efeitos dos fármacos , Estresse Oxidativo/genética , Proteína Serina-Treonina Quinases de Interação com Receptores/genética
6.
Water Sci Technol ; 82(4): 704-714, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32970623

RESUMO

The radical generation properties of hydrogen peroxide and persulfate for phenol degradation were investigated under microwave irradiation using copper-doped silicon carbide (Cu/SiC) composites as catalyst. The results showed that 90% and 70% of phenol and total organic carbon (TOC), respectively, were removed within 7 min. Microwave activation of hydrogen peroxide and sodium persulfate in terms of thermal effects and accelerated electron transfer was analyzed by degradation kinetics and X-ray photoelectron spectroscopy (XPS). The microwave activation of Na2S2O8 demonstrated that the hot spots promote decomposition of persulfate more rapidly and the rate of persulfate decomposition was more than three times the activation rate of a normal heating method. There is a synergistic effect between Cu and microwave radiation, which is highlighted by the H2O2 activation; ·OH was generated due to the redox cycle between Cu(I)/Cu(II) and was responsible for phenol degradation using H2O2. High performance liquid chromatography (HPLC) analysis indicated that hydroxylation and sulfate radicals addition of phenol were the initial oxidation reaction steps of hydrogen peroxide and persulfate, respectively, followed by further oxidation to form short-chain carboxylic acids.


Assuntos
Peróxido de Hidrogênio , Fenol , Compostos Inorgânicos de Carbono , Catálise , Micro-Ondas , Oxirredução , Compostos de Silício
7.
Chemosphere ; 258: 127411, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947668

RESUMO

Non-steroidal anti-inflammatory drugs as an important group of emerging environmental contaminants in irrigation water and soils can influence biochemical and physiological processes essential for growth and development in plants as non-target organisms. Plants are able to take up, transport, transform, and accumulate drugs in the roots. Root biomass in ten-days old pea plants was lowered by 6% already under 0.1 mg/L naproxen (NPX) due to a lowered number of lateral roots, although 0.5 mg/L NPX stimulated the total root length by 30% as against control. Higher section area (by 40%) in root tip, area of xylem (by 150%) or stele-to-section ratio (by 10%) in zone of maturation, and lower section area in zone of lateral roots (by 18%) prove the changes in primary root anatomy and its earlier differentiation at 10 mg/L NPX. Accumulated NPX (up to 10 µg/g DW at 10 mg/L) and products of its metabolization in roots increased the amounts of hydrogen peroxide (by 33%), and superoxide (by 62%), which was reflected in elevated lipid peroxidation (by 32%), disruption of membrane integrity (by 89%) and lowering both oxidoreductase and dehydrogenase activities (by up to 40%). Elevated antioxidant capacity (SOD, APX, and other molecules) under low treatments decreased at 10 mg/L NPX (both by approx. 30%). Naproxen was proved to cause changes at both cellular and tissue levels in roots, which was also reflected in their anatomy and morphology. Higher environmental loading through drugs thus can influence even the root function.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Naproxeno/toxicidade , Ervilhas/fisiologia , Antioxidantes/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Estresse Oxidativo/efeitos dos fármacos , Ervilhas/efeitos dos fármacos , Raízes de Plantas
8.
Nat Commun ; 11(1): 4512, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908147

RESUMO

Hydrogen peroxide (H2O2) is recognized to act as a signaling molecule. Peroxiredoxins (Prxs) have the ability to transfer H2O2-derived oxidizing equivalents to redox-regulated target proteins, thus facilitating the transmission of H2O2 signals. It has remained unclear how Prxs and their target proteins are brought together to allow for target-specific protein thiol oxidation. Addressing the specific case of Prx2-dependent STAT3 oxidation, we here show that the association of the two proteins occurs prior to Prx oxidation and depends on a scaffolding protein, the membrane chaperone annexin A2. Deletion or depletion of annexin A2 interrupts the transfer of oxidizing equivalents from Prx2 to STAT3, which is observed to take place on membranes. These findings support the notion that the Prx2-STAT3 redox relay is part of a highly organized membrane signaling domain.


Assuntos
Anexina A2/metabolismo , Peroxirredoxinas/metabolismo , Fator de Transcrição STAT3/metabolismo , Anexina A2/genética , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Dissulfetos/metabolismo , Células HEK293 , Humanos , Peróxido de Hidrogênio/metabolismo , Oxirredução , Ligação Proteica , Domínios Proteicos , Transdução de Sinais
9.
Trials ; 21(1): 785, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32928313

RESUMO

OBJECTIVES: 1- To compare the effectiveness of 1% Hydrogen peroxide, 0.2% Povidone-Iodine, 2% hypertonic saline and a novel solution Neem extract (Azardirachta indica) in reducing intra-oral viral load in COVID-19 positive patients. 2- To determine the salivary cytokine profiles of IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ and IL- 17 among COVID-19 patients subjected to 1% Hydrogen peroxide, 0.2% Povidone-Iodine, 2% hypertonic saline or Neem extract (Azardirachta indica) based gargles. TRIAL DESIGN: This will be a parallel group, quadruple blind-randomised controlled pilot trial with an add on laboratory based study. PARTICIPANTS: A non-probability, purposive sampling technique will be followed to identify participants for this study. The clinical trial will be carried out at the Aga Khan University Hospital (AKUH), Karachi, Pakistan. The viral PCR tests will be done at main AKUH clinical laboratories whereas the immunological tests (cytokine analysis) will be done at the Juma research laboratory of AKUH. The inclusion criteria are laboratory-confirmed COVID-19 positive patients, male or female, in the age range of 18-65 years, with mild to moderate disease, already admitted to the AKUH. Subjects with low Glasgow coma score, with a history of radiotherapy or chemotherapy, who are more than 7 days past the onset of COVID- 19 symptoms, or intubated or edentulous patients will be excluded. Patients who are being treated with any form of oral or parenteral antiviral therapy will be excluded, as well as patients with known pre-existing chronic mucosal lesions such as lichen planus. INTERVENTION AND COMPARATOR: Group A (n=10) patients on 10 ml gargle and nasal lavage using 0.2% Povidone-Iodine (Betadiene® by Aviro Health Inc./ Pyodine® by Brooks Pharma Inc.) for 20-30 seconds, thrice daily for 6 days. Group B (n=10) patients will be subjected to 10 ml gargle and nasal lavage using 1% Hydrogen peroxide (HP® by Karachi Chemicals Products Inc./ ActiveOxy® by Boumatic Inc.) for 20-30 seconds, thrice daily for 6 days. Group C will comprised of (n=10) subjects on 10ml gargle and nasal lavage using Neem extract solution (Azardirachta indica) formulated by Karachi University (chemistry department laboratories) for 20-30 seconds, thrice daily for 6 days. Group D (n=10) patients will use 2% hypertonic saline (Plabottle® by Otsuka Inc.) gargle and nasal lavage for a similar time period. Group E (n=10) will serve as positive controls. These will be given simple distilled water gargles and nasal lavage for 20-30 seconds, thrice daily for six days. For nasal lavage, a special douche syringe will be provided to each participant. Its use will be thoroughly explained by the data collection officer. After each use, the patient is asked not to eat, drink, or rinse their mouth for the next 30 minutes. MAIN OUTCOMES: The primary outcome is the reduction in the intra-oral viral load confirmed with real time quantitative PCR. RANDOMISATION: The assignment to the study group/ allocation will be done using the sealed envelope method under the supervision of Clinical Trial Unit (CTU) of Aga Khan University, Karachi, Pakistan. The patients will be randomised to their respective study group (1:1:1:1:1 allocation ratio) immediately after the eligibility assessment and consent administration is done. BLINDING (MASKING): The study will be quadruple-blinded. Patients, intervention provider, outcome assessor and the data collection officer will be blinded. The groups will be labelled as A, B, C, D or E. The codes of the intervention will be kept in lock & key at the CTU and will only be revealed at the end of study or if the study is terminated prematurely. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): As there is no prior work on this research question, so no assumptions for the sample size calculation could be made. The present study will serve as a pilot trial. We intend to study 50 patients in five study groups with 10 patients in each study group. For details, please refer to Fig. 1 for details. TRIAL STATUS: Protocol version is 7.0, approved by the department and institutional ethics committees and clinical trial unit of the university hospital. Recruitment is planned to start as soon as the funding is sanctioned. The total duration of the study is expected to be 6 months i.e. August 2020-January 2021. TRIAL REGISTRATION: This study protocol was registered at www.clinicaltrials.gov on 10 April 2020 NCT04341688 . FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2). Fig. 1 Flow diagram of study-participants' timeline.


Assuntos
Azadirachta , Betacoronavirus , Infecções por Coronavirus , Peróxido de Hidrogênio/administração & dosagem , Pandemias , Extratos Vegetais/administração & dosagem , Pneumonia Viral , Povidona-Iodo/administração & dosagem , Solução Salina Hipertônica/administração & dosagem , Carga Viral , Adulto , Anti-Infecciosos Locais/administração & dosagem , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/terapia , Feminino , Hospitalização , Humanos , Masculino , Monitorização Imunológica/métodos , Antissépticos Bucais/administração & dosagem , Lavagem Nasal/métodos , Pneumonia Viral/diagnóstico , Pneumonia Viral/imunologia , Pneumonia Viral/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Carga Viral/efeitos dos fármacos , Carga Viral/métodos
10.
Clin Oral Investig ; 24(10): 3707-3713, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32876748

RESUMO

OBJECTIVES: SARS-CoV-2 is mainly transmitted by inhalation of droplets and aerosols. This puts healthcare professionals from specialties with close patient contact at high risk of nosocomial infections with SARS-CoV-2. In this context, preprocedural mouthrinses with hydrogen peroxide have been recommended before conducting intraoral procedures. Therefore, the aim of this study was to investigate the effects of a 1% hydrogen peroxide mouthrinse on reducing the intraoral SARS-CoV-2 load. METHODS: Twelve out of 98 initially screened hospitalized SARS-CoV-2-positive patients were included in this study. Intraoral viral load was determined by RT-PCR at baseline, whereupon patients had to gargle mouth and throat with 20 mL of 1% hydrogen peroxide for 30 s. After 30 min, a second examination of intraoral viral load was performed by RT-PCR. Furthermore, virus culture was performed for specimens exhibiting viral load of at least 103 RNA copies/mL at baseline. RESULTS: Ten out of the 12 initially included SARS-CoV-2-positive patients completed the study. The hydrogen peroxide mouthrinse led to no significant reduction of intraoral viral load. Replicating virus could only be determined from one baseline specimen. CONCLUSION: A 1% hydrogen peroxide mouthrinse does not reduce the intraoral viral load in SARS-CoV-2-positive subjects. However, virus culture did not yield any indication on the effects of the mouthrinse on the infectivity of the detected RNA copies. CLINICAL RELEVANCE: The recommendation of a preprocedural mouthrinse with hydrogen peroxide before intraoral procedures is questionable and thus should not be supported any longer, but strict infection prevention regimens are of paramount importance. TRIAL REGISTRATION: German Clinical Trials Register (ref. DRKS00022484).


Assuntos
Betacoronavirus , Infecções por Coronavirus , Pandemias , Pneumonia Viral , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Peróxido de Hidrogênio , Masculino , Pessoa de Meia-Idade , Antissépticos Bucais , Projetos Piloto , Estudos Prospectivos , Carga Viral , Adulto Jovem
11.
Acta Odontol Latinoam ; 33(2): 59-68, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920607

RESUMO

The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.


Assuntos
Resinas Compostas/química , Peróxido de Hidrogênio/química , Clareadores Dentários/química , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Viscosidade/efeitos dos fármacos , Cor , Humanos , Teste de Materiais
12.
J Endod ; 46(9S): S19-S25, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32950190

RESUMO

INTRODUCTION: The ability to resolve pulpal inflammation to achieve predictable regeneration of the dentin-pulp complex has remained elusive and presents a challenge for clinicians and researchers. Although the dentin-pulp complex can react naturally to injury by forming a bridge of reparative dentin that protects the pulp from further damage, this process is significantly impaired if inflammation persists. Because the secretion of inflammatory cytokines by injured pulpal cells causes significant pain and discomfort to patients, it is critical to resolve pulpal inflammation in a timely manner so as to create a microenvironment conducive for pulpal healing and reparative dentin formation. The emergent field of regenerative endodontics has encouraged the development and application of biologically driven therapies that take advantage of the intrinsic healing capacities of host cells within dental pulp and the periapical complex. METHODS: These studies were designed to test the hypothesis that exposure to hypoxic conditions can modulate the production of inflammatory cytokines/factors by mesenchymal cells in vitro. A multi-domain peptide hydrogel system that is highly conducive for the growth and differentiation of tooth-derived stem cells was used for these studies. Stem cells from human exfoliated deciduous teeth (SHEDs) were first cultured within 3-dimensional hydrogel constructs and then challenged with hypoxic stresses via addition of H2O2. RESULTS: MDP constructs were successfully generated, challenged with H2O2, decellularized and lyophilized, forming a potential biomaterial containing hypoxia induced repair molecules. The ability of cell-derived factors to convert the phenotype of lipopolysaccharide-primed macrophages from a proinflammatory to a pro-resolving state was examined in the presence of the lyophilized SHED cell constructs. CONCLUSIONS: Our data suggest that hypoxia induced SHED cell products can be captured within the hydrogel system and may be useful in the resolution of pulpal inflammation to create a favorable microenvironment for regeneration of the dentin-pulp complex.


Assuntos
Polpa Dentária , Regeneração , Humanos , Peróxido de Hidrogênio , Hipóxia , Inflamação
13.
Sci Total Environ ; 740: 140152, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927549

RESUMO

This is the first study to investigate ethylenediamine-N,N'-disuccinic acid (EDDS)/photo-Fenton process to polish real wastewater containing pesticides for possible water reuse. To this end, simultaneous degradation of pesticides ametrine, atrazine, imidacloprid and tebuthiuron was evaluated in distilled water (DW) and in sewage treatment plant (STP) effluent at initial pH 6.0. Several operational parameters (Fe3+-EDDS concentration, Fe3+-EDDS molar ratio, EDDS addition patterns and radiation source) were evaluated. 80-98% removal of target pesticides were obtained in DW using 30 µmol L-1 of Fe3+-EDDS with a molar ratio of 1:2 (300 µmol L-1 of H2O2). In addition, the proposed Fe3+-EDDS photo-Fenton at pH 6 was more efficient than classic photo-Fenton at pH 2.7 (30-84% removal). Experiments conducted in the presence of radical trapping agents (2-propanol or chloroform) revealed that HO• was the most active radical during treatment. Matrix composition strongly affected the degradation of target pesticides as a six-fold higher concentration of reagents (180 µmol L-1 of Fe3+-EDDS and 1800 µmol L-1 of H2O2) was needed to reach the same efficiency in STP compared to DW. Even so, first order rate constants corresponding to the degradation of pesticides in DW (k = 0.098-0.85 min-1) were nearly two-fold higher than in STP (k = 0.079-0.49 min-1) under the same radiation source (black-light or solar radiation). Finally, acute toxicity towards Vibrio fischeri and Drosophila melanogaster flies, and antibacterial activity assessed for Escherichia coli were eliminated after the application of the proposed treatment, thus indicating environmental safety for either discharge or reuse of treated wastewater for crop irrigation in agriculture.


Assuntos
Anti-Infecciosos , Praguicidas , Poluentes Químicos da Água/análise , Animais , Drosophila melanogaster , Peróxido de Hidrogênio , Ferro , Oxirredução
14.
Sci Total Environ ; 740: 140379, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927555

RESUMO

The Antarctic Peninsula is one of the regions to be most affected by increase in sea surface temperatures (SSTs) mediated by Global Climate Change; indeed, most negative predictions imply an up to 6 °C increment by the end of the XXI century. Temperature is one of the most important factors mediating diversity and distribution of macroalgae, although there is still no consensus as to the likely effects of higher SSTs, especially for polar seaweeds. Some available information suggests that potential strategies to withstand future increases in SSTs will be founded upon the glutathione-ascorbate cycle and the induction of chaperone-functioning heat shock proteins (HSPs); however, their eventual role, even for general stress responses, is unclear. The intertidal green, brown and red macroalgae species Monostroma hariotii, Adenocystis utricularis and Pyropia endiviifolia, respectively, from King George Island, Antarctic Peninsula, were exposed to 2 °C (control) and 8 °C (climate change scenario) for up to 5 days (d). Photosynthetic activity (αETR and ETRmax, and EkETR), photoinhibition (Fv/Fm) and photoprotection processes (αNPQ, NPQmax, and EkNPQ) provided no evidence of negative ecophysiological effects. There were moderate increases in H2O2 production and levels of lipid peroxidation with temperature, results supported by stable levels of total glutathione and ascorbate pools, with mostly higher levels of reduced ascorbate and glutathione than oxidized forms in all species. Transcripts of P. endiviifolia indicated a general upregulation of all antioxidant enzymes and HSPs genes studied under warmer temperature, although with different levels of activation with time. This pioneering investigation exploring different levels of biological organization, suggested that Antarctic intertidal macroalgae may be able to withstand future rise in SSTs, probably slightly altering their latitudinal distribution and/or range of thermal tolerance, by exhibiting robust glutathione-ascorbate production and recycling, as well as the induction of associated antioxidant enzymatic machinery and the syntheses of HSPs.


Assuntos
Alga Marinha , Regiões Antárticas , Mudança Climática , Peróxido de Hidrogênio , Oceanos e Mares , Temperatura
15.
J Environ Sci (China) ; 97: 110-119, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933726

RESUMO

FeVO4/CeO2 was applied in the electro-Fenton (EF) degradation of Methyl Orange (MO) as a model of wastewater pollution. The results of the characterization techniques indicate that FeVO4 with triclinic structure and face-centered cubic fluorite CeO2 maintained their structures during the nanocomposite synthesis. The effect of applied current intensity, initial pollutant concentration, initial pH, and catalyst weight was investigated. The MO removal reached 96.31% and chemical oxygen demand (COD) removal 70% for 60 min of the reaction. The presence of CeO2 in the nanocomposite plays a key role in H2O2 electro-generation as a significant factor in the electro-Fenton (EF) system. The metal leaching from FeVO4/CeO2 was negligible (cerium 4.1%, iron 4.3%, and vanadium 1.7%), which indicates that the active species in the nanocomposite are strongly interacting with each other and are stable. The performance of the nanocatalyst in real wastewaters, salty, and binary systems was acceptable and the pollutions were removed efficiently. The synergistic effect between V, Fe, and Ce could be account as the reason for the respectable function of FeVO4/CeO2. The electron transfer proceeds via Haber-Weiss mechanism. A degradation pathway was proposed through by-products analysis using gas chromatography-mass spectrometry (GC-MS) technique. The pseudo-first-order kinetic model described the obtained experimental results (R2 = 0.9906). The electro-Fenton system efficiency was improved by adding persulfate. The nanocomposite preserved almost its efficiency after six cycles. The obtained results demonstrate that the synergistic catalyst (FeVO4/CeO2) has the capability to introduce as a promising replacement of conventional catalysts in the electro-Fenton processes with brilliant proficiency.


Assuntos
Nanocompostos , Poluentes Químicos da Água/análise , Catálise , Peróxido de Hidrogênio , Ferro , Oxirredução , Águas Residuárias
16.
Water Sci Technol ; 82(3): 481-491, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32960793

RESUMO

Iron oxyhydroxides as important catalysts and environmental mineral materials have drawn significant interest for their potential applications in the field of wastewater treatment. In this work, we investigated the influence of nonionic surfactant Brij30 or glucose (0.01 wt%) on the formation of iron precipitates in iron(III) chloride solutions for 3 days at 40, 60 and 80 °C. The results showed that the presence of glucose or Brij30 could promote the nanospindle-akaganéite formation and the akaganéite with a length of 300-500 nm obtained at 60 °C was the optimal catalyst for organic photocatalysis degradation. Further, we investigated the capacity of C60 akaganéite for degradation removal of methyl orange (MO) under the action of hydrogen peroxide (H2O2) addition and/or UV irradiation, and in the presence of different radical scavengers at pH 4.5. We also researched the effects of various levels of H2O2 and catalyst, and the reaction pH values. It was found that akaganéites could remove almost 100% of MO under 100 mg·L-1 of catalyst and H2O2 at pH 4.5. Akaganéite maintained 86% of MO removal capacity after four successive cycles. Our results can be used as a reference for the synthesis of environmentally functional material and the application in photocatalytic degradation of organic pollutant.


Assuntos
Compostos Férricos , Peróxido de Hidrogênio , Compostos Azo , Catálise
17.
Water Sci Technol ; 82(3): 565-576, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32960800

RESUMO

The heterogeneous electro-Fenton process degradation of Yellow 2G from wastewater was studied using a batch reactor. The COD of the wastewater used in treatment experiments was 163 mg O2·L-1 and the BOD5 was 17 mg O2·L-1 (hardly biodegradable). The treatment of the wastewater at different current densities (2.5 mA·cm-2-12.5 mA·cm-2), solution pH (3 and 6.6), reaction times (5-25 min), electrolyte nature (NaCl, Na2SO4) and electrolyte concentrations (0.15 g·L-1-1 g·L-1) was investigated. According to the results, the heterogeneous electro-Fenton process was suitable for the decolorization of wastewater containing Yellow 2G. The optimum conditions were current density of 12.5 mA·cm-2, initial pH of the wastewater neutral, 25 min of electrolysis treatment using an additive steel electrode as a source of catalysis and in the presence of 1 g NaCl·L-1. We obtained easily biodegradable water with a mineralization rate equal to 85% and non-toxicity confirmed by the pea grain germination test.


Assuntos
Aço , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Catálise , Eletrodos , Peróxido de Hidrogênio , Oxirredução , Pirazóis
18.
Environ Monit Assess ; 192(10): 657, 2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32968831

RESUMO

Simple, low-cost, and sensitive methods for the assessment of hexavalent chromium as an important environmental pollutant are highly desirable, especially under resource-limited settings. Therefore, herein we propose an original approach for the simple, low-cost, selective, and extremely sensitive assessment of Cr(VI) utilizing its catalysis of the micellar sensitized o-dianisidine (DA)-hydrogen peroxide reaction. The initial rate of the amended reaction is monitored by tracing the oxidation product, either by a digital camera video recording or spectrophotometrically at 440 nm, for 120 s from mixing the reactants. The optimized reaction conditions were 5 mmol L-1 DA, 0.6 mol L-1 H2O2, 2.0 v/v% Tween 20, and 10 mmol L-1 chloroacetate buffer (pH 4.5 ± 0.1), at 30 °C. The linear calibration graph extends to 90.0 ng mL-1 Cr(VI) with detection limits (3Sb) of 0.8 and 1.0 ng mL-1, for the video recording and spectrophotometric procedures, respectively. The amended method was successfully applied to the assessment of Cr(IV) in natural and polluted industrial wastewaters. The analytical data were in excellent statistical harmony with those of the standard ETAAS method. The proposed method is two orders of magnitude more sensitive than the diphenylcarbazide standard spectrophotometric method.Graphical abstract.


Assuntos
Colorimetria , Peróxido de Hidrogênio , Cromo/análise , Monitoramento Ambiental
19.
Quintessence Int ; 51(10): 788-797, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32901243

RESUMO

OBJECTIVES: This split-mouth study assessed the bleaching sensitivity (risk and intensity) and color change after in-office bleaching using a desensitizing-containing (5% potassium nitrate) and a desensitizing-free 35% hydrogen peroxide gel. The null hypothesis was that there would be no differences between study groups regarding bleaching sensitivity. METHOD AND MATERIALS: Sixty patients participated in this split-mouth study. The subjects received desensitizing-containing hydrogen peroxide in half of the maxillary arch, and the other half received a desensitizing-free hydrogen peroxide, defined by random sequence, in two dental bleaching sessions. The bleaching sensitivity was evaluated during bleaching and from 1 h to 48 h after each bleaching session using a visual analog scale and numeric rating scale; the McNemar test, the Wilcoxon signed-rank test, and the Student-Newman-Keuls test were used for statistical analysis. The color was measured at baseline and 30 days post-bleaching, evaluated with paired t tests (P = .05). RESULTS: Statistically similar risks of bleaching sensitivity were observed (P = 1.000), but the intensity of bleaching sensitivity was lower (P < .011) on average by 1.32 visual analog scale units in the group bleached with the desensitizer-containing gel during up to 24 h assessment times. No statistical difference in color change was observed between groups (P > .321). CONCLUSION: The incorporation of 5% potassium nitrate into in-office bleaching gels does not reduce the risk of bleaching sensitivity, but it reduces its intensity slightly without jeopardizing color change.


Assuntos
Sensibilidade da Dentina , Clareadores Dentários , Clareamento Dental , Sensibilidade da Dentina/induzido quimicamente , Método Duplo-Cego , Géis , Humanos , Peróxido de Hidrogênio , Clareadores Dentários/efeitos adversos , Resultado do Tratamento
20.
PLoS Comput Biol ; 16(9): e1008202, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32925922

RESUMO

Hydrogen peroxide (H2O2) promotes a range of phenotypes depending on its intracellular concentration and dosing kinetics, including cell death. While this qualitative relationship has been well established, the quantitative and mechanistic aspects of H2O2 signaling are still being elucidated. Mitochondria, a putative source of intracellular H2O2, have recently been demonstrated to be particularly vulnerable to localized H2O2 perturbations, eliciting a dramatic cell death response in comparison to similar cytosolic perturbations. We sought to improve our dynamic and mechanistic understanding of the mitochondrial H2O2 reaction network in HeLa cells by creating a kinetic model of this system and using it to explore basal and perturbed conditions. The model uses the most current quantitative proteomic and kinetic data available to predict reaction rates and steady-state concentrations of H2O2 and its reaction partners within individual mitochondria. Time scales ranging from milliseconds to one hour were simulated. We predict that basal, steady-state mitochondrial H2O2 will be in the low nM range (2-4 nM) and will be inversely dependent on the total pool of peroxiredoxin-3 (Prx3). Neglecting efflux of H2O2 to the cytosol, the mitochondrial reaction network is expected to control perturbations well up to H2O2 generation rates ~50 µM/s (0.25 nmol/mg-protein/s), above which point the Prx3 system would be expected to collapse. Comparison of these results with redox Western blots of Prx3 and Prx2 oxidation states demonstrated reasonable trend agreement at short times (≤ 15 min) for a range of experimentally perturbed H2O2 generation rates. At longer times, substantial efflux of H2O2 from the mitochondria to the cytosol was evidenced by peroxiredoxin-2 (Prx2) oxidation, and Prx3 collapse was not observed. A refined model using Monte Carlo parameter sampling was used to explore rates of H2O2 efflux that could reconcile model predictions of Prx3 oxidation states with the experimental observations.


Assuntos
Peróxido de Hidrogênio/metabolismo , Mitocôndrias/metabolismo , Modelos Biológicos , Neoplasias/metabolismo , Biologia Computacional , Citosol/química , Citosol/metabolismo , Células HeLa , Humanos , Cinética , Mitocôndrias/química , Neoplasias/química , Espécies Reativas de Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/fisiologia
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