Sublethal neurotoxicity of saxitoxin in early zebrafish development: Impact on sensorimotor function and neurotransmission systems

Saxitoxin (STX) represents a marine toxin of significant concern due to its deleterious implications for aquatic ecosystems and public food safety. As a potent paralytic agent, the role of STX in obstructing voltage-gated sodium channels (VGSCs) is well-characterized. Yet, the mechanistic details underlying its low-dose toxicity remain largely enigmatic. In the current study, zebrafish embryos and larvae were subjected to subchronic exposure of graded STX concentrations (0, 1, 10, and 100 μg/L) until the 7th day post-fertilization. A tactile stimulus-based assay was employed to evaluate potential behavioral perturbations resulting from STX exposure. Both behavioral and transcription level analyses unveiled a compromised tactile response, which was found to be associated with a notable upregulation in the mRNA of two distinct VGSC isoforms, specifically the scn8aa/ab and scn1Laa/ab transcripts, even at the minimal STX dose. Notably, exposure to this lowest STX concentration also resulted in alterations in the transcriptional patterns of pivotal genes for cholinergic and GABAergic pathways, including ache and gabra1. Furthermore, STX induced a marked decrease in the levels of the neurotransmitter GABA. Our findings underscore that prolonged low-dose STX exposure during early development can significantly compromise the tactile response behavior in zebrafish. This study reveals that chronic low-dose STX exposure of developing zebrafish alters neurotransmission pathways that converge on altered tactile behavior.

Increase of catastrophic and impoverishing health expenditures in Mexico associated to policy changes and the COVID-19 pandemic

Background

In 2003, the Mexican Congress approved a major reform to provide health care services to the poor population through the public insurance scheme Seguro Popular. This program was dismantled in 2019 as part of a set of health system reforms and substituted with the Health Institute for Welfare (INSABI). These changes were implemented during the initial phases of the coronavirus (COVID-19) pandemic. We aimed to examine the impact of these reforms and the COVID-19 pandemic on financial risk protection in Mexico between 2018 and 2020.

Methods

We performed a population-based analysis using cross-sectional data from the 2018 and 2020 rounds of the National Household Income and Expenditures Survey. We used a pooled fixed-effects multivariable two-stage probit model to determine the likelihood of catastrophic health expenditure (CHE), impoverishing health expenditure (IHE), and excessive health expenditure (EHE) among Mexican households. We also mapped the quintiles of changes in EHE in households without health insurance by state.

Results

The percentage of households without health insurance almost doubled from 8.8% (three million households) in 2018 to 16.5% (5.8 million households) in 2020. We also found large increases in the proportion of households incurring in CHE (18.4%; 95% confidence interval (CI) = 6.1, 30.7) and EHE (18.7%; 95% CI = 7.9, 29.5). Significant increases in CHE, IHE, and EHE were only observed among households without health insurance (CHE: 90.7%; 95% CI = 31.6, 149.7, EHE: 73.5%; 95% CI = 25.3, 121.8). Virtually all Mexican states (n/N = 31/32) registered an increase in EHE among households without health insurance. This increase has a systematic territorial component affecting mostly central and southern states (range = -1.0% to 194.4%).

Conclusions

The discontinuation of the Seguro Popular Program and its substitution with INSABI during the first stages of the COVID-19 pandemic reduced the levels of health care coverage in Mexico. This reduction and the pandemic increased out-of-pocket expenditure in health and the portion of CHE and EHE in the 2018-2020 period. The effect was higher in households without health insurance and households in central and southern states of the country. Further studies are needed to determine the specific effect both of recent policy changes and of the COVID-19 pandemic on the levels of financial protection in health in Mexico.

The ferryl generation by fenton reaction driven by catechol

The Fenton and Fenton-like reactions are based on the decomposition of hydrogen peroxide catalyzed by Fe(II), primarily producing highly oxidizing hydroxyl radicals (HO∙). While HO∙ is the main oxidizing species in these reactions, Fe(IV) (FeO2+) generation has been reported as one of the primary oxidants. FeO2+ has a longer lifetime than HO∙ and can remove two electrons from a substrate, making it a critical oxidant that may be more efficient than HO∙. It is widely accepted that the preferential generation of HO∙ or FeO2+ in the Fenton reaction depends on factors such as pH and Fe: H2O2 ratio. Reaction mechanisms have been proposed to generate FeO2+, which mainly depend on the radicals generated in the coordination sphere and the HO∙ radicals that diffuse out of the coordination sphere and react with Fe(III). As a result, some mechanisms are dependent on prior HO∙ radical production. Catechol-type ligands can induce and amplify the Fenton reaction by increasing the generation of oxidizing species. Previous studies have focused on the generation of HO∙ radicals in these systems, whereas this study investigates the generation of FeO2+ (using xylidine as a selective substrate). The findings revealed that FeO2+ production is increased compared to the classical Fenton reaction and that FeO2+ generation is mainly due to the reactivity of Fe(III) with HO∙ from outside the coordination sphere. It is proposed that the inhibition of FeO2+ generation via HO∙ generated from inside the coordination sphere is caused by the preferential reaction of HO∙ with semiquinone in the coordination sphere, favoring the formation of quinone and Fe(III) and inhibiting the generation of FeO2+ through this pathway.

Catalytic Selective Oxidation of β-O-4 Bond in Phenethoxybenzene as a Lignin Model Using (TBA)5[PMo10V2O40] Nanocatalyst: Optimization of Operational Conditions

The catalytic oxidation of phenethoxybenzene as a lignin model compound with a β-O-4 bond was conducted using the Keggin-type polyoxometalate nanocatalyst (TBA)5[PMo10V2O40]. The optimization of the process's operational conditions was carried out using response surface methodology. The statistically significant variables in the process were determined using a fractional factorial design. Based on this selection, a central circumscribed composite experimental design was used to maximize the phenethoxybenzene conversion, varying temperature, reaction time, and catalyst load. The optimal conditions that maximized the phenethoxybenzene conversion were 137 °C, 3.5 h, and 200 mg of catalyst. In addition, under the optimized conditions, the Kraft lignin catalytic depolymerization was carried out to validate the effectiveness of the process. The depolymerization degree was assessed by gel permeation chromatography from which a significant decrease in the molar mass distribution Mw from 7.34 kDa to 1.97 kDa and a reduction in the polydispersity index PDI from 6 to 3 were observed. Furthermore, the successful cleavage of the β-O-4 bond in the Kraft lignin was verified by gas chromatography-mass spectrometry analysis of the reaction products. These results offer a sustainable alternative to efficiently converting lignin into valuable products.

Silver nanoparticles modified ZnO nanocatalysts for effective degradation of ceftiofur sodium under UV-vis light illumination

Light-induced photocatalytic degradation of ceftiofur sodium (CFS) has been assessed in the presence of plasmonic zinc oxide nanostructures (ZnONSTs), like, ZnO nanoparticles, ZnO nanorods (ZnONRs) and ZnO nanoflowers (ZnONFs). Silver nanoparticles (Ag NPs) loaded ZnO nanostructures (Ag-ZnONSTs) are obtained through seed-assisted chemical reaction followed by chemical reduction of silver. The surface modification of ZnO nanostructures by Ag NPs effectually altered their optical properties. Further, the surface plasmonic effect of Ag NPs facilitates visible light absorption by ZnONSTs and improved the photogenerated electron and hole separation, which makes the ZnONSTs a more active photocatalyst than TiO₂ (P25) nanoparticles. Especially, Ag-ZnONRs showed higher CFS oxidation rate constant (k' = 4.6 × 10^-4 s^-1) when compared to Ag-ZnONFs (k' = 2.8 × 10^-4 s^-1) and Ag-ZnONPs (k' = 2.5 × 10^-4 s^-1), owing to their high aspect ratio (60:1). The unidirectional transport of photogenerated charge carriers on the Ag-ZnONRs may be accountable for the observed high photocatalytic oxidation of CFS. The photocatalytic oxidation of CFS mainly proceeds through ^•OH radicals generated on the Ag-ZnONRs surface under light illumination. In addition, heterogeneous activation of peroxymonosulfate by Ag-ZnONRs accelerates the rate of photocatalytic mineralization of CFS. The quantification of oxidative radicals supports the proposed CFS oxidation mechanism. Stability studies of plasmonic Ag-ZnONSTs strongly suggests that it could be useful to clean large volume of pharmaceutical wastewater under direct solar light irradiation.

Berberis microphylla G. Forst Intake Reduces the Cardiovascular Disease Plasmatic Markers Associated with a High-Fat Diet in a Mice Model

Polyphenols are bioactive substances that participate in the prevention of chronic illnesses. High content has been described in Berberis microphylla G. Forst (calafate), a wild berry extensively distributed in Chilean-Argentine Patagonia. We evaluated its beneficial effect through the study of mouse plasma metabolome changes after chronic consumption of this fruit. Characterized calafate extract was administered in water, for four months, to a group of mice fed with a high-fat diet and compared with a control diet. Metabolome changes were studied using UHPLC-DAD-QTOF-based untargeted metabolomics. The study was complemented by the analysis of protein biomarkers determined using Luminex technology, and quantification of OH radicals by electron paramagnetic resonance spectroscopy. Thirteen features were identified with a maximum annotation level-A, revealing an increase in succinic acid, activation of tricarboxylic acid and reduction of carnitine accumulation. Changes in plasma biomarkers were related to inflammation and cardiovascular disease, with changes in thrombomodulin (-24%), adiponectin (+68%), sE-selectin (-34%), sICAM-1 (-24%) and proMMP-9 (-31%) levels. The production of OH radicals in plasma was reduced after calafate intake (-17%), especially for the group fed with a high-fat diet. These changes could be associated with protection against atherosclerosis due to calafate consumption, which is discussed from a holistic and integrative point of view.

Nanostructured electrochemical sensor applied to the electrocoagulation of arsenite in WWTP effluent

A sensitive electroanalytical method for the determination of arsenite, based on a heterostructure of aminated multiwalled carbon nanotubes and gold nanoparticles, was applied in an electrocoagulation (EC) treatment for the elimination of arsenite. A sensitive quantitative response was obtained in the determination of As³⁺ in a secondary effluent from a wastewater treatment plant from Santiago (Chile). The preconcentration stage was optimized through a Central Composite Face design, and the most sensitive peak current was obtained at 200 s and -600 mV of time and accumulation potential, respectively, after a differential pulse voltammetry sweep. Electroanalytical determination was possible in an interval between 42.89 and 170.00 μg L^-1 with a detection limit of 0.39 μg L^-1, obtaining recoveries over 99.1%. The developed method was successfully applied in an electrocoagulation treatment to remove 250 μg L^-1 of arsenite from a polluted effluent in a batch system. Complete arsenite removal was achieved using a steel EC system with a current density of 6.0 mA cm^-2 in less than 3 min of treatment.

Influence of RE (Pr3+, Er3+, Nd3+) doping on structural, vibrational and enhanced persistent photocatalytic properties of ZnO nanostructures

Rare earth (RE- Pr, Er and Nd) doped ZnO nanostructures were prepared through simple wet chemical precipitation route. The RE doping induced interesting morphological transition from spherical to flower like structures were analyzed. The X-ray diffraction (XRD) measurements revealed that the prepared materials were of highly crystalline in nature and RE dopant ions did not altered the crystal structure of ZnO. The microstrain of ZnO was altered with respect to the nature of dopants. In the case of the Pr doped ZnO, X-ray photoelectron spectroscopy (XPS) analysis confirmed that the dopant (Pr) ions successfully substituted in the ZnO lattice. Raman spectra revealed RE doping induced lower energy side shift and variation in intensity of the peaks related to the characteristic phonon modes of ZnO. In the case of Nd doped ZnO nanostructures, dopant induced suppression in classical Raman modes and evolution of multiphonon related modes were identified. Optical diffuse reflectance spectral (DRS) measurements, along with the characteristic excitonic band of ZnO, other bands associated to the transitions of 4f energy levels related to the RE ions were observed. The partially filled 4f orbitals led to the enhanced photocatalytic activity in RE doped ZnO nanostructures. The observed enhanced photocatalytic activity in RE doped ZnO when compared to bare ZnO was discussed. The decolorization efficiency of MB ensued the following order 96 > 94 > 86 > 78% for ZnErO, ZnNdO, ZnPrO and ZnO, respectively.

Role of perhydroxyl radical in the chelator-mediated Fenton reaction

The chelator-mediated Fenton (CMF) chemistry is one of the main biological non-enzymatic systems for oxygen-centered radical generation. Perhydroxyl radical (HO2•) is a secondary radical specie in CMF systems, however, despite...

In vitro evaluation of the protective effect of crocin on human erythrocytes

The interactions and the protective effect of the carotenoid crocin (CRO) on human erythrocytes (RBC) and molecular models of its membrane were investigated. The latter consisted of bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representative of phospholipid classes located in the outer and inner monolayers of the RBC membrane, respectively. X-ray diffraction, differential scanning calorimetry (DSC) and electronic paramagnetic resonance spectroscopy (EPR) showed that CRO produced structural perturbations in DMPC bilayers and in isolated unsealed human erythrocyte membranes. On the other hand, scanning electron microscopy (SEM) showed that CRO induced shape changes in the RBC from their normal discoid form to echinocytes. This result indicates that the CRO molecules were mainly localized in the outer monolayer of the RBC membrane. The assessment of the protective capacity of CRO was revealed by the carotenoid inhibition of the morphological alterations caused by hypochlorous acid (HOCl) to RBC.

Piscirickettsia salmonis Produces a N-Acetyl-L-Homoserine Lactone as a Bacterial Quorum Sensing System-Related Molecule

Piscirickettsia salmonis is the etiological agent of piscirickettsiosis, the most prevalent disease in salmonid species in Chilean salmonids farms. Many bacteria produce N-acyl-homoserine lactones (AHLs) as a quorum-sensing signal molecule to regulate gene expression in a cell density-dependent manner, and thus modulate physiological characteristics and several bacterial mechanisms. In this study, a fluorescent biosensor system method and gas chromatography-tandem mass spectrometry (GC/MS) were combined to detect AHLs produced by P. salmonis. These analyses revealed an emitted fluorescence signal when the biosensor P. putida EL106 (RPL4cep) was co-cultured with both, P. salmonis LF-89 type strain and an EM-90-like strain Ps007, respectively. Furthermore, the production of an AHL-type molecule was confirmed by GC/MS by both P. salmonis strains, which identified the presence of a N-acetyl-L-homoserine Lactone in the supernatant extract. However, It is suggested that an alternate pathway could synthesizes AHLs, which should be address in future experiments in order to elucidate this important bacterial process. To the best of our knowledge, the present report is the first to describe the type of AHLs produced by P. salmonis.

Provision of a protein-rich supplement for grazing suckling female beef calves to improve productive performance and metabolic response

Objective

This study was conducted to evaluate the effects of the provision of a protein-rich supplement on productive performance, and metabolic profile on grazing suckling female beef calves in tropical conditions during 150 d of experimentation.

Methods

Fifty-six Nellore suckling female calves, and their respective dams were distributed in a completely randomised design and made to undergo two treatments as follows: UNS (without supplementation), and SUP (supplementation with 5 g/kg body weight [BW] of a protein supplement). Throughout the experiment, animal performance and metabolic profile were evaluated. Also, ureagenesis and gluconeogenesis were assessed for gene expression.

Results

SUP female calves showed a higher voluntary intake (p≤0.03) of the diet components evaluated, digestibility of organic matter (p≤0.02) and microbial nitrogen production (MICN; p≤0.02) compared to UNS female calves. In its turn, serum urea nitrogen (p≤0.01) and insulin-like growth factor-1 (p≤0.03) levels and ureagenesis (p≤0.04) increased in SUP female calves compared to UNS female calves. Blood glucose and triglyceride levels were not affected by supplementation. The average daily gain (ADG) from SUP female calves was higher (p≤0.02) compared with UNS female calves. However, supplementation did not affect the body measures of the animals.

Conclusion

In summary, provision of a protein-rich supplement improves the intake and nutrients digestibility, ADG and final BW and increases metabolic indicators of the protein status in grazing suckling female beef calves in tropical conditions.

When You "Can't See" a Case of Relapsing Polychondritis

Relapsing polychondritis (RP) is a rare and, if not treated, potentially lethal autoimmune disorder. Involvement of central nervous system (CNS) in RP is rare and, when present, makes it extremely difficult to diagnose. In this report, we present a case of a 22-year-old Hispanic woman who presented with sudden onset of headache and blurred vision. Magnetic resonance imaging (MRI) of her brain and orbit showed leptomeningeal enhancements in addition to asymmetrical thickening and enhancement of globes. Her lumbar puncture was consistent with aseptic meningitis picture, and she was placed on empirical treatment for presumptive CNS tuberculosis. Her vision deteriorated, and she was diagnosed with RP with CNS and ocular involvement and placed on high-dose steroids with dramatic rapid response. She has been on immunosuppressive treatment, including Sulfasalazine and Methotrexate, since then and her disease has been under control with decreased need for ophthalmic steroid drops. There have been only 19 previous cases found in literature reporting an association of RP with CNS involvement.

Lemierre Syndrome in a Patient With Splenectomy Secondary to Pyruvate Kinase Deficiency, Complicated by Heparin Resistance

Lemierre syndrome was first documented in the literature in 1936, and is defined as septic thrombophlebitis of the internal jugular vein. It is typically a result of oropharyngeal infection causing local soft tissue inflammation, which spreads to vasculature, and promotes formation of septic thrombi within the lumen, persistent bacteremia, and septic emboli. We present the case of a 24-year-old incarcerated man, who presented with leukocytosis and a right-sided tender, swollen neck after undergoing left mandibular molar extraction for an infected tooth. Computed tomography revealed a persistent thrombus in the transverse and sigmoid sinuses bilaterally, extending downwards, into the upper jugular veins. He was started on empiric intravenous vancomycin, zosyn, and heparin, but subsequently demonstrated heparin resistance, and was thus anticoagulated with a lovenox bridge to warfarin. Throughout his hospital course, hemocultures demonstrated no growth, so antibiotic treatment was deescalated to oral metronidazole and ceftriaxone. On discharge, the patient was transitioned to oral amoxicillin and metronidazole for an additional 4 weeks with continuation of anticoagulation with warfarin for a total of 3 to 6 months. This case report details a unique presentation of Lemierre syndrome with bilateral transverse sinus, sigmoid sinus, and internal jugular vein thrombosis that was presumably secondary to an odontogenic infectious focus.

Behavioural Fever Promotes an Inflammatory Reflex Circuit in Ectotherms

Background: The communication between the brain and the immune system is a cornerstone in animal physiology. This interaction is mediated by immune factors acting in both health and pathogenesis, but it is unclear how these systems molecularly and mechanistically communicate under changing environmental conditions. Behavioural fever is a well-conserved immune response that promotes dramatic changes in gene expression patterns during ectotherms’ thermoregulatory adaptation, including those orchestrating inflammation. However, the molecular regulators activating the inflammatory reflex in ectotherms remain unidentified. Methods: We revisited behavioural fever by providing groups of fish a thermal gradient environment during infection. Our novel experimental setup created temperature ranges in which fish freely moved between different thermal gradients: (1) wide thermoregulatory range; T° = 6.4 °C; and (2) restricted thermoregulatory range; T° = 1.4 °C. The fish behaviour was investigated during 5-days post-viral infection. Blood, spleen, and brain samples were collected to determine plasmatic pro- and anti-inflammatory cytokine levels. To characterize genes’ functioning during behavioural fever, we performed a transcriptomic profiling of the fish spleen. We also measured the activity of neurotransmitters such as norepinephrine and acetylcholine in brain and peripheral tissues. Results: We describe the first set of the neural components that control inflammatory modulation during behavioural fever. We identified a neuro-immune crosstalk as a potential mechanism promoting the fine regulation of inflammation. The development of behavioural fever upon viral infection triggers a robust inflammatory response in vivo, establishing an activation threshold after infection in several organs, including the brain. Thus, temperature shifts strongly impact on neural tissue, specifically on the inflammatory reflex network activation. At the molecular level, behavioural fever causes a significant increase in cholinergic neurotransmitters and their receptors’ activity and key anti-inflammatory factors such as cytokine Il10 and Tgfβ in target tissues. Conclusion: These results reveal a cholinergic neuronal-based mechanism underlying anti-inflammatory responses under induced fever. We performed the first molecular characterization of the behavioural fever response and inflammatory reflex activation in mobile ectotherms, identifying the role of key regulators of these processes. These findings provide genetic entry points for functional studies of the neural–immune adaptation to infection and its protective relevance in ectotherm organisms.

Overview of toxic cyanobacteria and cyanotoxins in Ibero-American freshwaters: Challenges for risk management and opportunities for removal by advanced technologies

The increasing occurrence of cyanobacterial blooms worldwide represents an important threat for both the environment and public health. In this context, the development of risk analysis and management tools as well as sustainable and cost-effective treatment processes is essential. The research project TALGENTOX, funded by the Ibero-American Science and Technology Program for Development (CYTED-2019), aims to address this ambitious challenge in countries with different environmental and social conditions within the Ibero-American context. It is based on a multidisciplinary approach that combines ecology, water management and technology fields, and includes research groups from Chile, Colombia, Mexico, Peru and Spain. In this review, the occurrence of toxic cyanobacteria and cyanotoxins in freshwaters from these countries are summarized. The presence of cyanotoxins has been confirmed in all countries but the information is still scarce and further monitoring is required. In this regard, remote sensing or metagenomics are good alternatives at reasonable cost. The risk management of freshwaters from those countries considering the most frequent uses (consumption and recreation) has been also evaluated. Only Spain and Peru include cyanotoxins in its drinking water legislation (only MC-LR) and thus, there is a need for regulatory improvements. The development of preventive strategies like diminishing nutrient loads to aquatic systems is also required. In the same line, corrective measures are urgently needed especially in drinking waters. Advanced Oxidation Processes (AOPs) have the potential to play a major role in this scenario as they are effective for the elimination of most cyanotoxins classes. The research on the field of AOPs is herein summarized considering the cost-effectiveness, environmental character and technical applicability of such technologies. Fenton-based processes and photocatalysis using solar irradiation or LED light represent very promising alternatives given their high cost-efficiency. Further research should focus on developing stable long-term operation systems, addressing their scale-up.

Determination of equilibrium constants of iron(iii)-1,2-dihydroxybenzene complexes and the relationship between calculated iron speciation and degradation of rhodamine B

The contribution of the monocomplex [Fe(DHB)]+ to the percentage of rhodamine B degradation is statistically significant.

Toxic effects of the anticancer drug epirubicin in vitro assayed in human erythrocytes

Epirubicin is a cytotoxic drug used in the treatment of different types of cancer and increasing evidence suggests that its target is cell membranes. In order to gain insight on its toxic effects, intact red blood cells (RBC), human erythrocyte membranes and molecular models were used. The latter consisted in bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), phospholipid classes found mainly in the outer and inner monolayers of the human erythrocyte membrane, respectively. The results obtained by X-ray diffraction displayed that epirubicin induced structural perturbations in multilayers of DMPC. Differential scanning calorimetry (DSC) showed that epirubicin disturbed the thermotropic behavior of both DMPC and DMPE vesicles, whereas fluorescence spectroscopy demonstrated alterations in the fluidity of DMPC vesicles and the erythrocyte membrane. Scanning electron microscopy (SEM) revealed that epirubicin changed the normal discoid form of RBC to echinocytes and stomatocytes. Electron paramagnetic resonance (EPR) disclosed that this drug induced conformational changes in the erythrocyte membrane proteins. These findings demonstrate that epirubicin interacts with lipids and proteins of the human erythrocyte membrane, effects that might compromise the integrity and function of cell membranes. This is the first time that its toxic effects on the human erythrocyte membrane have been described.

Impact of oenological antioxidant substances on the formation of 1-hydroxyethyl radical and phenolic composition in SO2 free red wines

BACKGROUND

Different natural substances, chitosan, inactive dry yeasts and freeze-dried aqueous extracts from two wine industry by-products (stems and shoots) were used in red winemaking as possible alternatives to SO₂ . The resistance to oxidation of wines was evaluated by electron paramagnetic resonance. The phenolic composition of wines was analyzed by high-performance liquid chromatography-diode array detection/electrospray ionization mass spectrometry, antioxidant activity was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl radical) and ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation] assays and spectrophotometric measurements of color were compared.

RESULTS

The wines elaborated with chitosan and inactive dry yeast presented greater capacity to inhibit the formation of the 1-hydroxyethyl radical compared to the wines elaborated with stem or shoot extracts. The total content of anthocyanins was higher in the wines elaborated with SO₂ ; however, the concentration of flavan-3-ols was higher in the wines with chitosan. In addition, the wines with chitosan and inactive dry yeast presented the highest % polymerization. Wines elaborated with stem extract had a lower concentration of flavonols and stilbenes.

CONCLUSION

Chitosan and inactive dry yeast, which are used as an alternative to SO₂ in winemaking, allow the control of the formation of 1-HER in red wines. Wines with stem and shoot extracts showed a lower resistance to oxidation. © 2020 Society of Chemical Industry.

Potential of Different Natural Antioxidant Substances to Inhibit the 1-Hydroxyethyl Radical in SO2-Free Wines

The potential of different natural antioxidants to inhibit the 1-hydroxyethyl radical formation in SO₂-free wines was analyzed by electron paramagnetic resonance (EPR). Chitosan, glutathione, inactive dry yeast, oak and grape seed extracts, and ascorbic acid were tested in white and red wines. The ability of these substances to prevent the formation of acetaldehyde after the Fenton reaction and the oxygen consumption capacity were measured. Ascorbic acid was the antioxidant substance that offered higher percentages of 1-hydroxyethyl radical inhibition at 30 min of reaction. However, wines with ascorbic acid showed higher concentrations of acetaldehyde after the Fenton reaction. Grape seed extract and chitosan provided higher percentages of radical inhibition in red wine than those in white wine, in contrast to the inactive dry yeast that only produced radical inhibition in white wine. Although oak extract did not produce changes in the 1-hydroxyethyl radical, wines with that extract had lower concentrations of acetaldehyde.

Assessment of a Fenton reaction driven by insoluble tannins from pine bark in treating an emergent contaminant

Iron ligands as 1,2-dihydroxybenzenes (1,2-DHBs) have been used to increase the oxidizing ability of Fenton systems. However, these kinds of ligands become toxic quinones in the process creating an environmental problem since these compounds cannot be easily separated from a solution. To avoid this problem, in the present work, water-insoluble tannins, obtained from Pinus radiata bark, were used as a source of 1,2-DHBs to promote the oxidizing ability of the Fenton process. The developed system was tested using atrazine, as a substrate, which is a toxic and recalcitrant compound, present in different sources of water. The best reaction conditions established by the experimental design were as follows: pH of 3.6; 2.4 mmol L^-1 of H₂O₂; 150 μmol L^-1 of Fe(III); and 800 mg L^-1 of tannins. A significant increase in the efficiency of the degradation of atrazine by the heterogeneous Fenton process was observed under these conditions. The repetitive use of the insoluble tannins for Fenton-like processes showed a similar oxidizing ability and did not produce the lixiviation of phenols or other aromatic compounds. Together, the results showed that insoluble tannins could be used safely at least five times to promote the reactivity of Fenton systems.

Highly efficient hydrogen evolution reaction, plasmon-enhanced by AuNP-l-TiO2NP photocatalysts

A set of AuNPs-l-TiO₂NPs nanoaggregates which showed efficient covering of the semiconductor's surface by AuNPs, as well as suitable AuNP sizes for LSPR-sensibilization were used as highly efficient photocatalysts for photoinduced HER.

Quantification of carbonate radical formation by the bicarbonate-dependent peroxidase activity of superoxide dismutase 1 using pyrogallol red bleaching

Carbonate radicals (CO₃•^-) are generated by the bicarbonate-dependent peroxidase activity of cytosolic superoxide dismutase (Cu,Zn-SOD, SOD-1). The present work explored the use of bleaching of pyrogallol red (PGR) dye to quantify the rate of CO₃•^- formation from bovine and human SOD-1 (bSOD-1 and hSOD-1, respectively). This approach was compared to previously reported methods using electron paramagnetic resonance spin trapping with DMPO, and the oxidation of ABTS (2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid). The kinetics of PGR consumption elicited by CO₃•^- was followed by visible spectrophotometry. Solutions containing PGR (5–200 μM), SOD-1 (0.3–3 μM), H₂O₂ (2 mM) in bicarbonate buffer (200 mM, pH 7.4) showed a rapid loss of the PGR absorption band centered at 540 nm. The initial consumption rate (R_i) gave values independent of the initial PGR concentration allowing an estimate to be made of the rate of CO₃•^- release of 24.6 ± 4.3 μM min⁻¹ for 3 μM bSOD-1. Both bSOD-1 and hSOD-1 showed a similar peroxidase activity, with enzymatic inactivation occurring over a period of 20 min. The single Trp residue (Trp³²) present in hSOD-1 was rapidly consumed (initial consumption rate 1.2 ± 0.1 μM min⁻¹) with this occurring more rapidly than hSOD-1 inactivation, suggesting that these processes are not directly related. Added free Trp was rapidly oxidized in competition with PGR. These data indicate that PGR reacts rapidly and efficiently with CO₃•^- resulting from the peroxidase activity of SOD-1, and that PGR-bleaching is a simple, fast and cheap method to quantify CO₃•^- release from bSOD-1 and hSOD-1 peroxidase activity.

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CO₃•^- are released during the bicarbonate-dependent peroxidase activity of SOD-1.

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The rate and extent of CO₃•^- release can be determined by pyrogallol red bleaching.

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Inactivation of bSOD-1 and hSOD-1 occurs rapidly during the reaction.

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SOD-1 inactivation is independent of the presence of pyrogallol red.

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This assay should help elucidate protein oxidation/crosslinking mediated by SOD-1.

Multivariate approach to hydrogenated TiO2 photocatalytic activity under visible light

The photocatalytic activity of hydrogenated TiO₂ was evaluated in the photooxidation of methyl orange (MO). The hydrogenation of TiO₂ was carried out by calcination of a mixture of TiO₂ P-25 and NaBH₄ , at 300 and 350°C for blue TiO₂ and black TiO₂ , respectively. An experimental design was made for the determination of the best reaction conditions for the oxidation of MO. The influence of catalyst dosage and pH on photocatalytic efficiency was optimized, and the degradation percentage of MO was the response factor. The photocatalytic reaction was performed using a Xenon lamp that simulates the solar light spectrum for the activation of the catalyst. It was determined that both blue and black TiO₂ show the greatest activity at pH = 2 and 0.8 g/L of catalyst. Additionally, the positive influence of hydrogen peroxide in the photocatalytic activity of both hydrogenated catalysts was determined. In parallel, COD and TOC were also studied. PRACTITIONER POINTS: The extent of titania reduction by hydrogenation is dependent on the reaction time with sodium borohydride. The extent of titania reduction affects the photocatalytic activity in the oxidation of methyl orange. An excess of catalyst reduction inhibits the oxidation of the dye because of the increase of recombination points. The best reaction conditions were determined by multivariate optimization as pH 2 and 0.8 g L^-1 of hydrogenated catalyst. The addition of hydrogen peroxide into the reaction system improves the oxidation yield attributed to their electron accepting capacity.

An Experimental Validated Computational Method for pKa Determination of Substituted 1,2-Dihydroxybenzenes

1,2-dihydroxybenzenes (DHBs) are organic compounds which are widely studied as they are applied to advanced oxidation processes (AOPs). These compounds are also related to the development of oxidative stress, wood biodegradation, and neuronal disease in humans. DHBs are metal ligands with pro-oxidant and antioxidant properties. These activities are related to their chelation properties and a consequence of the deprotonation of their hydroxyl groups. In literature, there are several pKa values for the hydroxyl groups of DHBs. These values vary depending on the experimental conditions or the algorithm used for calculation. In this work, an experimentally validated computational method was implemented in aqueous solution for pKa determination of 24 DHBs. The deprotonation order of the hydroxyl groups in DHB was determined observing a selective deprotonation, which depended on the ability of the substituent to donate or withdraw electron density over the ring.

Bosutinib Inhibits EGFR Activation in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, and although new therapeutic approaches have been recently evaluated, overall patient survival is still poor. Thus, new effective and selective clinical treatments are urgently needed. An analysis of data from large-scale, high-throughput drug screening cell line projects identified Bosutinib, a Src/Abl inhibitor that is currently used for the treatment of chronic myelogenous leukemia, as a candidate drug to treat HNSCC. Using a panel of HNSCC-derived cell lines, we found that treatment with Bosutinib reduced cell proliferation and induced apoptosis of sensitive cell lines. The drug rapidly inhibited Src and EGFR (epidermal growth factor receptor) phosphorylation, and sensitivity to Bosutinib was correlated with the activation status of EGFR. Similar findings were observed in in vivo xenograft assays using HNSCC derived cells. Moreover, in the presence of mutations in PIK3CA, the combination of Bosutinib with the PI3Kα inhibitor Alpelisib showed a synergistic effect. These results suggest that Bosutinib could be a new effective drug for the treatment of HNSCC, particularly in tumors with high EGFR activity. Its combination with Alpelisib could especially benefit patients bearing activating mutations of PIK3CA.

Iron Overload Is Associated With Oxidative Stress and Nutritional Immunity During Viral Infection in Fish

Iron is a trace element, essential to support life due to its inherent ability to exchange electrons with a variety of molecules. The use of iron as a cofactor in basic metabolic pathways is essential to both pathogenic microorganisms and their hosts. During evolution, the shared requirement of micro- and macro-organisms for this important nutrient has shaped the pathogen-host relationship. Infectious pancreatic necrosis virus (IPNv) affects salmonids constituting a sanitary problem for this industry as it has an important impact on post-smolt survival. While immune modulation induced by IPNv infection has been widely characterized on Salmo salar, viral impact on iron host metabolism has not yet been elucidated. In the present work, we evaluate short-term effect of IPNv on several infected tissues from Salmo salar. We observed that IPNv displayed high tropism to headkidney, which directly correlates with a rise in oxidative stress and antiviral responses. Transcriptional profiling on headkidney showed a massive modulation of gene expression, from which biological pathways involved with iron metabolism were remarkable. Our findings suggest that IPNv infection increase oxidative stress on headkidney as a consequence of iron overload induced by a massive upregulation of genes involved in iron metabolism.

Green synthesis of porous Au–Nx-TiO2 nanospheres for solar light induced photocatalytic degradation of diazo and triazo dyes and their eco-toxic effects

The photocatalytic activity of Au–N_x-TiO₂ nanospheres evaluated under natural sunlight; 91% mineralization of azo dyes is achieved without toxic intermediates.

Effect of reduced graphene oxide on the structural, optical, adsorption and photocatalytic properties of iron oxide nanoparticles

Effect of reduced graphene oxide on the structural and photocatalytic properties of Fe₂O₃ nanoparticles.

The Reactivity and Reaction Pathway of Fenton Reactions Driven by Substituted 1,2-Dihydroxybenzenes

Fenton systems are interesting alternatives to advanced oxidation processes (AOPs) applied in soil or water remediation. 1,2-Dihydroxybenzenes (1,2-DHBs) are able to amplify the reactivity of Fenton systems and have been extensively studied in biological systems and for AOP applications. To develop efficient AOPs based on Fenton systems driven by 1,2-DHBs, the change in reactivity mediated by different 1,2-DHBs must be understood. For this, a systematic study of the reactivity of Fenton-like systems driven by 1,2-DHBs with different substituents at position 4 was performed. The substituent effect was analyzed using the Hammett constant (σ), which has positive values for electron-withdrawing groups (EWGs) and negative values for electron-donating groups (EDGs). The reactivity of each system was determined from the degradation of a recalcitrant azo dye and hydroxyl radical (HO·) production. The relationship between these reactivities and the ability of each 1,2-DHB to reduce Fe(III) was determined. From these results, we propose two pathways for HO· production. The pathway for Fenton-like systems driven by 1,2-DHBs with EDGs depends only on the Fe(III) reduction mediated by 1,2-DHB. In Fenton-like reactions driven by 1,2-DHBs with EWGs, the Fe(III) reduction is not primarily responsible for increasing the HO· production by this system in the early stages.

Hydroxyl radical production by a heterogeneous Fenton reaction supported in insoluble tannin from bark of Pinus radiata

Fenton reactions driven by dihydroxybenzenes (DHBs) have been used for pollutant removal via advanced oxidation processes (AOPs), but such systems have the disadvantage of DHB release into the aqueous phase. In this work, insoluble tannins from bark can be used to drive Fenton reactions and as a heterogeneous support. This avoids the release of DHBs into the aqueous phase and can be used for AOPs. The production of ·OH was investigated using a spin-trapping electron paramagnetic resonance technique (5-dimethyl-1-pyrroline-N-oxide/·OH) in the first minute of the reaction and a high-performance liquid chromatography-fluorescence technique (coumarin/7-hydroxycoumarin) for 20 min. The ·OH yield achieved using insoluble tannins from Pinus radiata bark was higher than that achieved using catechin to drive the Fenton reaction. The Fenton-like system driven by insoluble tannins achieved 92.6 ± 0.3 % degradation of atrazine in 30 min. The degradation kinetics of atrazine was linearly correlated with ·OH production. The increased reactivity in ·OH production and insolubility of the ligand are promising for the development of a new technique for degradation of pollutants in wastewater using heterogeneous Fenton systems.

A New Kinetic Spectrophotometric Method for the Quantitation of Amorolfine

Amorolfine (AOF) is a compound with fungicide activity based on the dual inhibition of growth of the fungal cell membrane, the biosynthesis and accumulation of sterols, and the reduction of ergosterol. In this work a sensitive kinetic and spectrophotometric method for the AOF quantitation based on the AOF oxidation by means of KMnO4 at 30 min (fixed time), pH alkaline, and ionic strength controlled was developed. Measurements of changes in absorbance at 610 nm were used as criterion of the oxidation progress. In order to maximize the sensitivity, different experimental reaction parameters were carefully studied via factorial screening and optimized by multivariate method. The linearity, intraday, and interday assay precision and accuracy were determined. The absorbance-concentration plot corresponding to tap water spiked samples was rectilinear, over the range of 7.56 × 10-6-3.22 × 10-5 mol L-1, with detection and quantitation limits of 2.49 × 10-6 mol L-1 and 7.56 × 10-6 mol L-1, respectively. The proposed method was successfully validated for the application of the determination of the drug in the spiked tap water samples and the percentage recoveries were 94.0-105.0%. The method is simple and does not require expensive instruments or complicated extraction steps of the reaction product.

Experimental and computational investigation of the substituent effects on the reduction of Fe3+by 1,2-dihydroxybenzenes

This study reports on the kinetics of the early steps of the reactions between substituted 1,2-dihydroxybenzenes (1,2-DHB) and Fe³⁺.

Ruthenium(ii) complexes incorporating carbazole–diazafluorene based bipolar ligands for dye sensitized solar cell applications

A new type of ruthenium sensitizers, S3 and S4, consisting of carbazole–diazafluorene based bipolar ancillary ligands have been synthesized and characterized for dye sensitized solar cells.

Reversal of the Hartmann's procedure: A comparative study of laparoscopic versus open surgery

BACKGROUND:

The Hartmann's operation, although less frequently performed today, is still used when initial colonic anastomosis is too risky in the short term. However, the subsequent procedure to restore gastrointestinal continuity is associated with significant morbidity and mortality.

PATIENTS AND METHODS:

The review of an institutional review board (IRB)-approved prospectively maintained database provided data on the Hartmann's reversal procedure performed by either laparoscopic or open technique at our institution. The data collected included: demographic data, operative approach, conversion for laparoscopic cases and perioperative morbidity and mortality.

RESULTS:

Over a 14-year period from January 1997 to August 2011, 74 Hartmann's reversal procedures were performed (laparoscopic surgery—49, open surgery—25). The average age was 55 years for the laparoscopic and 57 years for the open surgery group, respectively. Male patients represent 61% of both groups. There was no significant difference in operative time between the two groups (149 min vs 151 min; P = 0.95), and there was a tendency to lower morbidity (3/49—7.3% vs 4/25—16%; P = 0.24) in the laparoscopic surgery group. In the laparoscopic group, eight patients (16.3%) were converted to open surgery, mostly due to severe adhesions. The length of hospital stay was significantly shorter for the laparoscopic group (5 days vs 7 days; P = 0.44).

CONCLUSIONS:

The Hartmann's reversal procedure can be safely performed in the majority of the cases using a laparoscopic approach with a low morbidity rate and achieving a shorter hospital stay.