Central obesity is detrimental to anti-inflammatory, phenotype, and exhaustion markers in mononuclear cells - A cross-sectional study.

OBJECTIVE: To investigate the role of central obesity on immunometabolic response in peripheral blood mononuclear cells (PBMCs) from normal weight and overweight/obese young men. METHODS: Eighteen individuals were classified as normal weight (NW; n = 9 - age: 25 ± 5 and BMI: 21.4 ± 1.7) and overweight/obese (OW; n = 9 - age: 29 ± 7 and BMI: 29.2 ± 2.7). The body composition was evaluated by dual-energy x-ray absorptiometry (DXA), waist circumference, and visceral and subcutaneous fat depots by ultrasound. Physical activity levels, metabolic parameters, immune phenotypic characterization, cytokine production by lipopolysaccharide (LPS) -stimulated whole blood cells and LPS or phorbol 12-myristate 13-acetate (PMA)-stimulated PBMC, and mitochondrial respiration in PBMCs were evaluated. Expression of AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma (PPAR-γ), nuclear factor-kappa B (NF-κB), toll-like receptor 4 (TLR-4), hypoxia-inducible factor-1 alpha (HIF-1α), and adrenergic receptor beta 1 and 2 (AR-ß1 and ß2) genes were evaluated in cultured PBMC using quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: Individuals with overweight/obese (OW) presented higher glucose (P = 0.009) and leptin (P = 0.010) than individuals with normal weight (NW). PBMCs of OW under stimulation with LPS presented a lower production of interleukin-10 (IL-10) (P = 0.011) and macrophage inflammatory protein-1alpha (MIP-1α) (P = 0.048) than NW. Mitochondrial respiration rates were not different between NW and OW subjects. Cultured PBMCs in LPS-stimulated condition indicated higher gene expression of AR-ß2 in OW, while PMA-stimulated PBMCs presented lower expression of AMPK (P = 0.002) and higher expression of NF-κB (P=<0.0001) than NW. OW presented higher numbers of CD3+CD4+ T cells (P = 0.009) and higher expression of programmed cell death protein 1 (PD-1) in CD8+ T cells (P = 0.001) than NW. CONCLUSION: Central obesity promoted reductions in interleukin 10 production response and increase in AR-ß2 expressions in mitogen-stimulated PBMCs. Furthermore, central obesity altered the phenotype of PBMCs, also increasing the expression of PD-1 exhaustion markers in young adults.

Mild to moderate post-COVID-19 alters markers of lymphocyte activation, exhaustion, and immunometabolic responses that can be partially associated by physical activity level- an observational sub-analysis fit- COVID study.

Aim: This study aimed to evaluate if physical activity is associated with systemic and cellular immunometabolic responses, in young adults after mild-to-moderate COVID-19 infection. Methods: Mild- to- moderate post-COVID-19 patients (70.50 ± 43.10 days of diagnosis; age: 29.4 (21.9- 34.9) years; BMI: 25.5 ± 4.3 kg m2 n = 20) and healthy age-matched controls (age: 29.3 (21.2 - 32.6) years; BMI: 25.4 ± 4.7 kg m2; n = 20) were evaluated. Physical activity levels (PAL), body composition, dietary habits, muscular and pulmonary function, mental health, sleep quality, metabolic parameters, immune phenotypic characterization, stimulated whole blood and PBMC culture (cytokine production), mRNA, and mitochondrial respiration in PBMCs were evaluated. Results: The post-COVID-19 group exhibited lower levels of moderate to vigorous physical activity (MVPA) (p = 0.038); therefore, all study comparisons were performed with adjustment for MVPA. Post-COVID-19 impacted the pulmonary function (FEV1, FEV1%pred, FVC, and FVC %pred) compared with the control (p adjusted by MVPA (p adj) <0.05). Post-COVID-19 exhibited lower levels of serum IL-6 (p adj <0.01), whereas it showed higher serum IL-10, triglyceride, leptin, IgG, ACE activity, TNFRSF1A, and PGE2 (p adj <0.05) levels compared with controls. Post-COVID-19 presented a lower percentage of Treg cells (p adj = 0.03) and altered markers of lymphocyte activation and exhaustion (lower CD28 expression in CD8+ T cells (p adj = 0.014), whereas CD4+T cells showed higher PD1 expression (p adj = 0.037)) compared with the control group. Finally, post- COVID-19 presented an increased LPS-stimulated whole- blood IL-10 concentration (p adj <0.01). When exploring mitochondrial respiration and gene expression in PBMCs, we observed a higher LEAK state value (p adj <0.01), lower OXPHOS activity (complex I) (p adj = 0.04), and expression of the Rev-Erb-α clock mRNA after LPS stimulation in the post-COVID-19 patients than in the control (p adj <0.01). Mainly, PAL was associated with changes in IL-10, triglyceride, and leptin levels in the plasma of post-COVID-19 patients. PAL was also associated with modulation of the peripheral frequency of Treg cells and the expression of PD-1 in CD8+ T cells, although it abrogated the statistical effect in the analysis of TNF-α and IL-6 production by LPS- and PMA-stimulated PBMC of post-COVID-19 patients. Conclusion: Young adults after mild-to-moderate SARS-CoV-2 infection appeared to have lower physical activity levels, which can be associated with clinical and immunometabolic responses in a complex manner.

Electrocatalytic Reduction of CO2 in Water by a Palladium-Containing Metallopolymer.

The palladium-salen complex was immobilized by electropolymerization onto a Pt disc electrode and applied as an electrocatalyst for the reduction of CO2 in an aqueous solution. Linear sweep voltammetry measurements and rotating disk experiments were carried out to study the electrochemical reduction of carbon dioxide. The onset overpotential for carbon dioxide reduction was approximately -0.22 V vs. NHE on the poly-Pd(salen) modified electrode. In addition, by combining the electrochemical study with a kinetic study, the rate-determining step of the electrochemical CO2 reduction reaction (CO2RR) was found to be the radial reduction of carbon dioxide to the CO adsorbed on the metal.

Resistance training prevents damage to the mitochondrial function of the skeletal muscle of rats exposed to secondary cigarette smoke.

AIM: To analyze the consumption of oxygen and to quantify the mitochondrial respiratory chain proteins (OXPHOS) in the gastrocnemius muscle of rats exposed to cigarette smoke and/or RT practitioners. MAIN METHODS: Wistar rats were divided into groups: Control (C), Smoker (S), Exercise (E) and Exercise Smoker (ES). Groups F and ES were exposed to the smoke of 4 cigarettes for 30 min, 2× a day, 5× a week, for 16 weeks. Groups E and ES performed four climbs with progressive load, 1× per day, 5× per week, for 16 weeks. The gastrocnemius muscle was collected for analysis of OXPHOS content and oxygen consumption. Groups S (vs. C) and ES (vs. C and E) showed lower body weight gain when observing the evolution curve. KEY FINDINGS: The S rats showed a reduction in the NDUFB8 proteins of complex 1, SDHB of complex 2, MTC01 of complex 4 and ATP5A of complex 5 (ATP Synthase) compared to Group C. Additionally, S rats also showed increased consumption of O2 in Basal, Leak, Complex I and I/II combined measures compared to the other groups, suggesting that the activity of the mitochondria of these animals increased in terms of coupling and uncoupling parameters. SIGNIFICANCE: Our data suggest that exposure to cigarette smoke for 16 weeks is capable of causing impairment of mitochondrial function with reduced expression of respiratory chain proteins in skeletal muscle. However, the RT was effective in preventing impairment of mitochondrial function in the skeletal muscle of rats exposed to secondary cigarette smoke.

Mechanism of Nanocomposite Formation in the Layer-by-Layer Single-Step Electropolymerization of π-Conjugated Azopolymers and Reduced Graphene Oxide: An Electrochemical Impedance Spectroscopy Study.

This work presents a study of the formation mechanism of electrochemically deposited alternating layers of azopolymer and graphene oxide, as well as a systematic study of the physicochemical characteristics of the resulting nanocomposite films by electrochemical impedance spectroscopy. The nanocomposite films were constructed by cyclic electropolymerization, which allowed for the assembly of thin films with alternating azopolymers and reduced graphene oxide (rGO) layers in one step. Morphological characterizations were performed by atomic force microscopy and scanning electron microscopy and verified that the electrodeposition of the poly(azo-BBY) polymeric film occurred during the anodic sweep, and the deposition of graphene oxide sheets took place during the cathodic sweep. By analyzing the electrochemical impedance spectra using equivalent circuit models, variations in the resistance and capacitance values of the system were monitored as a function of the amount of electrodeposited material on the fluorine doped tin oxide electrode. In addition, the interfacial phenomena that occurred during the electroreduction of the rGO sheets were monitored with the same method.

Photochemiresistor Sensor Development Based on a Bismuth Vanadate Type Semiconductor for Determination of Chemical Oxygen Demand.

The present paper describes the development of a novel photochemiresistor sensor for the determination of chemical oxygen demand (COD). A chemiresistive device was produced by a thin film of the monoclinic phase of bismuth vanadate deposited on an FTO glass surface. The resistive properties of the photosensor were carried out by electrochemical impedance spectroscopy (EIS). The electrical resistance of the platform was dependent on the presence of organic material in aqueous solution and the incidence of light. The decrease in resistance can be explained by considering that by increasing the amount of organic material, the amount of charge transferred to BiVO4 increases, as does the amount of the photogenerated conduction band on the film. This behavior is not observed when carrying out the same measurements in the absence of light. Under the optimal experimental conditions, the linear response of the chemiresistor sensor is between 0.20 and 19.9 mg L-1 COD at a fixed AC frequency of 0.1 Hz. There is a good correlation between the charge transfer resistance and COD concentration in the electrolyte solution. Quantification of COD in waste and lake waters was successfully performed using the novel photochemiresistor sensor. The results achieved in the analysis with the sensor are in accordance with the conventional method.

Carboxymethyl-botryosphaeran stabilized carbon nanotubes aqueous dispersion: A new platform design for electrochemical sensing of desloratadine.

The polysaccharide carboxymethyl-botryosphaeran (CMB) was used to improve the dispersion of multi-walled carbon nanotubes (MWCNTs) in water. This feature was applied in modifying a glassy carbon electrode (GCE) to construct a sensitive voltammetric sensor for the determination of desloratadine (DESL), a tricyclic antihistamine. The morphology and spectroscopic behavior of the sensor were evaluated. The modified sensor was characterized as homogeneous, and presented a higher electroactive area and a lower charge transfer resistance compared to the unmodified GCE. Using linear sweep voltammetry at 25 mV s-1, the developed sensor presented a sensitivity of 1.018 µA L µmol-1 in the linear working range of 1.99-32.9 µmol L-1, with a detection limit of 0.88 µmol L-1 of DESL in 0.10 mol L-1 potassium hydrogen-phosphate solution (pH 8.0). In addition, the sensor showed excellent repeatability with a relative standard deviation of only 1.02% for a sequence of 10 measurements. The sensor was successfully applied in the analysis of pharmaceutical preparations containing DESL, with equivalent results compared to a validated spectrophotometric method at the 95% confidence level. The sensor was also employed in the analysis of a spiked sample of DESL in rat serum.

An Electrochemical Sensor Based on Nanostructured Hollandite-type Manganese Oxide for Detection of Potassium Ions.

The participation of cations in redox reactions of manganese oxides provides an opportunity for development of chemical sensors for non-electroactive ions. A sensor based on a nanostructured hollandite-type manganese oxide was investigated for voltammetric detection of potassium ions. The detection is based on the measurement of anodic current generated by oxidation of Mn(III) to Mn(IV) at the surface of the electrode and the subsequent extraction of the potassium ions into the hollandite structure. In this work, an amperometric procedure at an operating potential of 0.80 V (versus SCE) is exploited for amperometric monitoring. The current signals are linearly proportional to potassium ion concentration in the range 4.97 × 10(-5) to 9.05 × 10(-4) mol L(-1), with a correlation coefficient of 0.9997.

A Chemiresistor Sensor Based on Azo-Polymer and Graphene for Real-Time Monitoring of Mitochondrial Oxygen Consumption.

In the present study, a chemiresistor sensor based on a poly(Bismarck Brown Y)-reduced graphene oxide nanocomposite was developed to analyze the respiratory capacity of the constituent complexes of the electron transport chain. The sensorial platform was characterized using electrochemical impedance spectroscopy, and oxygen detection was accomplished by measuring the resistive properties of the sensor at fixed AC frequency. The impedance decreased significantly in response to small variations of the O2 concentrations tested up to saturation of the electrolyte solution with molecular oxygen. The resistive response of the sensor at 0.1 Hz was linear over the oxygen concentration range from 1.17 × 10-5 mol L-1 to 1.02 × 10-3 mol L-1, with a detection limit of 3.60 × 10-7 mol L-1. Using the new O2 sensing platform, we monitored gradients in static cultures of adherent cells exposed to graded oxygen both at rest and upon metabolic stimulation. Under high dissolved oxygen conditions, the respiration of resting cells dictated that local O2 was moderately reduced, while cell metabolic stimulation triggered a major redistribution of O2. The usefulness of the developed sensor was demonstrated by continuous monitoring of mitochondrial oxygen consumption in various biologic applications.

A chemiresistor sensor based on a cobalt(salen) metallopolymer for dissolved molecular oxygen.

A resistance detection device for dissolved molecular oxygen in aqueous solutions is prepared using a chemiresistor material as sensor platform. The chemiresistive circuit element is fashioned from a thin film of a cobalt-salen metallopolymer electrodeposited on a platinum electrode. Electrochemical impedance spectroscopy shows that the resistive and capacitive properties of the sensor platform depend on the presence of dissolved oxygen. The electrical circuit models are R(Q/R)(Q/R) and R(Q/R)(Q/RW) in the absence and presence of oxygen, respectively. The chemiresistor sensor exhibits good sensitivity (0.483 kΩ L mg-1), excellent reversibility and excellent linearity over a range of dissolved oxygen concentrations typically found under environmental conditions (2.72-40.9 mg L-1). The sensor fabricated in this work can potentially serve as an alternative sensor for the detection of dissolved oxygen in environmental samples.

Analytical development of a binuclear oxo-manganese complex bio-inspired on oxidase enzyme for doping control analysis of acetazolamide.

A bio-inspired electrochemical sensor using a binuclear oxo-manganese complex was evaluated and applied in the detection of a substance associated with doping in sports: acetazolamide (ACTZ). Investigation was made of the influence of different experimental variables on the electrocatalytic oxidation of ACTZ by the bio-inspired sensor, such as pH and interfering species. The bio-inspired sensor showed the best response in the range from 5.00×10(-9) to 7.00×10(-8) mol L(-1) ACTZ, with a linear range from 5.00×10(-9) to 2.50×10(-8) mol L(-1) and a detection limit of 4.76×10(-9) mol L(-1). The sensor exhibited characteristics similar to the Michaelis-Menten model of an enzymatic electrode, due to the use of a multinucleated complex of manganese with µ-oxo units, which was able to mimic the properties of enzymes with manganese as a cofactor in their composition, such as Mn-containing oxidase. The determination of ACTZ with the bio-inspired sensor was evaluated using three different synthetic biological fluids (plasma, saliva, and urine), demonstrating its viability for use with real samples. The analysis of ACTZ in real urine samples using the bio-inspired sensor, simulating the method adopted by the World Anti-Doping Agency, which revealed viable, suggesting a new and promising platform to be used in these analysis.

Electrochemical investigation of the voltammetric determination of hydrochlorothiazide using a nickel hydroxide modified nickel electrode.

The preparation and electrochemical characterization of a nickel hydroxide modified nickel electrode as well as its behavior as electrocatalyst toward the oxidation of hydrochlorothiazide (HCTZ) were investigated. The electrochemical behavior of the modified electrode and the electrooxidation of HCTZ were explored using cyclic voltammetry. The voltammetric response of the modified electrode in the detection of HCTZ is based on the electrochemical oxidation of the Ni(II)/Ni(III) and a chemical redox process. The analytical parameters for the electrooxidation of HCTZ by the nickel hydroxide modified nickel electrode were obtained in NaOH solution, in which the linear voltammetric response was in the concentration range from 1.39×10(-5) to 1.67×10(-4)mol L(-1) with a limit of detection of 7.92×10(-6)mol L(-1) and a sensitivity of 0.138 µA Lmmol(-1). Tafel analysis was used to elucidate the kinetics and mechanism of HCTZ oxidation by the modified electrode.

Differential pulse anodic voltammetric determination of lithium ions in pharmaceutical formulations using a carbon paste electrode modified with spinel-type manganese oxide.

The use of the differential pulse voltammetry for the determination of lithium ions in pharmaceutical samples using a carbon paste electrode modified with spinel-type manganese oxide has been examined. The best voltammetric response was reached for a modified electrode in borate buffer solution of pH 9.0 and submitted to a scan rate of 5 mV s(-1) and a pulse amplitude of 50 mV. This electroanalytical procedure was able to determine lithium ions in the concentration range of 8.0 x 10(-5)-1.0 x 10(-2) mol l(-1) even in the presence of several alkali metals (1.0 x 10(-3) mol l(-1)) with a detection limit of 7.1 x 10(-7) mol l(-1). Rapidity, precise and good selectivity were also found for the determination of lithium ions in pharmaceutical formulations.

Flow injection spectrophotometric determination of adrenaline in pharmaceutical formulations using a solid-phase reactor containing lead(IV) dioxide immobilized in a polyester resin.

A flow injection spectrophotometric procedure is proposed for determining adrenaline in pharmaceutical formulations. In this work, the adrenaline in acetate buffer reacts with a solid-phase reactor containing lead(IV) dioxide immobilized in a polyester resin and the adrenochrome yielded was continuously monitored at 486 nm. The analytical curve was linear in the adrenaline concentration range from 0.1 to 0.8 mmol l(-1) with a detection limit of 8 x 10(-3) mmol l(-1). Recoveries of 96.5-105% and relative standard deviation of 0.2% for a solution containing 0.4 mmol l(-1) adrenaline (n = 10) were obtained. The analytical frequency was 130 determinations per hour and the results obtained for adrenaline in pharmaceutical formulations using this procedure and those obtained using a pharmacopoeia procedure are in agreement at the 95% confidence level.

Flow injection amperometric determination of dipyrone in pharmaceutical formulations using a carbon paste electrode.

The behavior of a carbon paste electrode was investigated as an amperometric detector for the determination of dipyrone by flow injection analysis (FIA). The electrode presented low cost and easy construction by simple mixing of graphite powder and mineral oil. Initially, an electrochemical study of the dipyrone oxidation at a carbon paste electrode has been developed before its use in the FIA system. The oxidation currents monitored at +0.35 V versus Ag/AgCl, were proportional to the dipyrone concentrations. Experimental parameters, such as nature of supporting electrolyte, pH of the carrier solution, flow rate, sample volume injection and probable interferents were investigated. Under the best experimental conditions selected, the calibration curve for dipyrone was linear in the concentration range from 4.91 x 10(-6) to 2.50 x 10(-4) M l(-1) (I(anodic)/microA)=0.056+81.06 [dipyrone]) with a detection limit of 2.07 x 10(-6) M l(-1). Recoveries ranged from 93.8 to 100.8% and an analytical frequency of 130 h(-1) was achieved. The proposed flow procedure has been satisfactorily applied to the determination of dipyrone in several pharmaceutical formulations.

Electrochemical sensor for ranitidine determination based on carbon paste electrode modified with oxovanadium (IV) salen complex.

The preparation and electrochemical characterization of a carbon paste electrode modified with the N,N-ethylene-bis(salicyllideneiminato)oxovanadium (IV) complex ([VO(salen)]) as well as its application for ranitidine determination are described. The electrochemical behavior of the modified electrode for the electroreduction of ranitidine was investigated using cyclic voltammetry, and analytical curves were obtained for ranitidine using linear sweep voltammetry (LSV) under optimized conditions. The best voltammetric response was obtained for an electrode composition of 20% (m/m) [VO(salen)] in the paste, 0.10 mol L(-1) of KCl solution (pH 5.5 adjusted with HCl) as supporting electrolyte and scan rate of 25 mV s(-1). A sensitive linear voltammetric response for ranitidine was obtained in the concentration range from 9.9×10(-5) to 1.0×10(-3) mol L(-1), with a detection limit of 6.6×10(-5) mol L(-1) using linear sweep voltammetry. These results demonstrated the viability of this modified electrode as a sensor for determination, quality control and routine analysis of ranitidine in pharmaceutical formulations.

A novel Mn-containing conducting metallopolymer obtained by electropolymerization in aqueous solution of a tetranuclear oxo-bridged manganese complex.

The [Mn(4)(IV)O(5)(terpy)(4)(H(2)O)(2)](6+) complex shows great potential for electrode modification by electropolymerization using cyclic voltammetry. The electropolymerization mechanism was based on the electron transfer between dx(2)-y(2) orbitals of the metallic center and pπ orbital of the ligand.

Voltammetric performance and application of a sensor for sodium ions constructed with layered birnessite-type manganese oxide.

The preparation and electrochemical characterization of a carbon paste electrode modified with layered birnessite-type manganese oxide for use as a sodium sensor is described. The effects of powder synthesis process (sol-gel and redox precipitation) for birnessite on the electrochemical activity of the sensor was investigated by cyclic voltammetry. The carbon paste electrode modified with birnessite-type manganese oxide that was synthesized by the sol-gel method showed a best electrochemical for sodium ions. The detection is based on the measurement of anodic current generated by oxidation of Mn(III) to Mn(IV) at the surface of the electrode and consequently the sodium ions extraction into the birnessite structure. The best voltammetric response was obtained for an electrode composition of 15% (w/w) birnessite oxide in the paste, a TRIS buffer solution of pH 8.0 and a scan rate of 50 mV s(-1). A sensitive linear voltammetric response for sodium ions was obtained in the concentration range of 7.89x10(-5) to 3.49x10(-4) mol L(-1) with a slope of 37.5 microA L mmol(-1) and a detection limit (3sigma/slope) of 3.43x10(-5) mol L(-1) using cyclic voltammetry. Under the working conditions, the proposed method was successfully applied to determination of sodium ions in urine samples.

Lithium ions determination by selective pre-concentration and differential pulse anodic stripping voltammetry using a carbon paste electrode modified with a spinel-type manganese oxide.

The use of selective pre-concentration and differential pulse anodic stripping voltammetry (DPASV) using a carbon paste electrode modified (CPEM) with spinel-type manganese oxide has been proposed for the determination of lithium ions content in natural waters. The new procedure is based on the effective pre-concentration of lithium ions on the electrode surface containing spinel-type Mn(IV) oxide with the reduction of Mn(IV) to Mn(III) and consequently the lithium ions intercalation (insertion) into the spinel structure. The best DPASV response was reached for an electrode composition of 25% (m/m) spinel-type MnO(2) in the paste, 0.1moll(-1) tris(hydroxymethyl)aminomethane (TRIS) buffer solution of pH 8.3, scan rate of 5mVs(-1), accumulation potential of 0.3V versus saturated calomel reference electrode (SCE), pre-concentration time of 30s and potential pulse amplitude of 50mV. In these experimental conditions, the proposed methodology responds to lithium ions in the concentration range of 2.8x10(-6) to 2.0x10(-3)moll(-1) with a detection limit of 5.6x10(-7)moll(-1). The determination of the lithium ions content in different samples of natural waters samples using the proposed methodology and atomic absorption spectrophotometry are in agreement at the 95% confidence level and within an acceptable range of error.

Carbon paste electrode modified with copper (II) phosphate immobilized in a polyester resin for voltammetric determination of L-ascorbic acid in pharmaceutical formulations.

A carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin (CuP-Poly) is proposed for voltammetric determination of L-ascorbic acid in pharmaceutical formulations. The modified electrode allows the detection of L-ascorbic acid at lower anodic potentials than observed at unmodified electrodes. Several parameters that can influence the voltammetric response of the proposed electrode such as carbon paste composition, pH, scan rate, and possible interference were investigated. The peak current was proportional to the concentration of ascorbic acid in the range 2.0 x 10(-5) to 3.2 x 10(-3) mol L(-1) with a detection limit of 1.0 x 10(-5) mol L(-1). The stability and repeatability of the electrode for the determination of L-ascorbic acid are also discussed. Amperometric response was also recorded for electrocatalytic oxidation of the L-ascorbic acid. Concentrations of the vitamin C in pharmaceutical formulations (tablets) measured using the modified electrode and a titrimetric method are in agreement at the 95% confidence level and within an acceptable range of error.