MnO2/TiO2-Catalyzed ozonolysis: enhancing Pentachlorophenol degradation and understanding intermediates.

Pentachlorophenol is a pesticide widely known for its harmful effects on sewage, causing harm to the environment. In previous studies, our group identified adsorption as a crucial factor in catalytic ozonation processes, and subsequent observations revealed the catalyst's role in reducing toxicity during degradation. In this research, we quantified organochlorine intermediates and low molecular weight organic acids generated under optimal pH conditions (pH 9), with and without the catalyst. Additionally, we assessed the reactivity of these intermediates through theoretical calculations. Our findings indicate that the catalyst reduces the duration of intermediates. Additionally, the presence of CO2 suggests enhanced mineralization of pentachlorophenol, a process notably facilitated by the catalyst. Theoretical calculations, such as Fukui analysis, offer insights into potential pathways for the dechlorination of aromatic molecules by radicals like OH, indicating the significance of this pathway.

Tetrahydrobiopterin (BH4) Supplementation Prevents the Cardiorenal Effects of Diabetes in Mice by Reducing Oxidative Stress, Inflammation and Fibrosis.

Background: The effects of diabetes on the cardiovascular system as well as in the kidney are profound, which include hypertrophy and fibrosis. Diabetes also induces oxidative stress, at least in part due to the uncoupling of nitric oxide synthase (NOS); this is a shift in NO production toward superoxide production due to reduced levels of the NOS cofactor tetrahydrobiopterin (BH4). With this in mind, we tested the hypothesis that BH4 supplementation may prevent the development of diabetic cardiomyopathy and nephropathy. Methods: Diabetes was induced in Balb/c mice with streptozotocin. Then, diabetic mice were divided into two groups: one group provided with BH4 (sapropterin) in drinking water (daily doses of 15 mg/kg/day, during eight weeks) and the other that received only water. A third group of normoglycemic mice that received only water were used as the control. Results: Cardiac levels of BH4 were increased in mice treated with BH4 (p = 0.0019). Diabetes induced cardiac hypertrophy, which was prevented in the group that received BH4 (p < 0.05). In addition, hypertrophy was evaluated as cardiomyocyte cross-sectional area. This was reduced in diabetic mice that received BH4 (p = 0.0012). Diabetes induced cardiac interstitial fibrosis that was reduced in mice that received BH4 treatment (p < 0.05). We also evaluated in the kidney the impact of BH4 treatment on glomerular morphology. Diabetes induced glomerular hypertrophy compared with normoglycemic mice and was prevented by BH4 treatment. In addition, diabetic mice presented glomerular fibrosis, which was prevented in mice that received BH4. Conclusions: These results suggest that chronic treatment with BH4 in mice ameliorates the cardiorenal effects of diabetes,, probably by restoring the nitroso−redox balance. This offers a possible new alternative to explore a BH4-based treatment for the organ damage caused by diabetes.

Use of Poly(vinyl alcohol)-Malic Acid (CLHPMA) Hydrogels and Chitosan Coated Calcium Alginate (CCCA) Microparticles as Potential Sorbent Phases for the Extraction and Quantitative Determination of Pesticides from Aqueous Solutions.

Pesticides are used worldwide to increase crop yields in agriculture. However, their toxicity and accumulation capacity can make them toxic to the environment, animals and humans. In the case of workers chronically exposed to these substances, they must be sampled continuously, so urine is an excellent option. In this sense, this study proposes to use poly(vinyl alcohol)-malic acid hydrogels, and chitosan-coated calcium alginate as new sorbent phases to be used in pesticide determination processes in urine. To better understand the behavior of these materials in the capture and desorption process, molecular dynamics simulations (MDS) were used, and desorption experiments were performed, using mechanical agitation, ultrasound, and pH variation in the desorption process, in order to optimize the parameters to obtain better recoveries. Under the optimal experimental conditions, the maximum recoveries were of the order of 11% (CFN), 3% (KCF), 53% (DMT), 18% (MTD) and 35% (MTL). Although the recoveries were not exhaustive, they are a first approximation for the use of these new sorbent phases in the determination of this type of compound in aqueous solutions and urine.

Preparation of Hydrogel/Silver Nanohybrids Mediated by Tunable-Size Silver Nanoparticles for Potential Antibacterial Applications.

In this study, a versatile synthesis of silver nanoparticles of well-defined size by using hydrogels as a template and stabilizer of nanoparticle size is reported. The prepared hydrogels are based on polyvinyl alcohol and maleic acid as crosslinker agents. Three hydrogels with the same nature were synthesized, however, the crosslinking degree was varied. The silver nanoparticles were synthesized into each prepared hydrogel matrix achieving three significant, different-sized nanoparticles that were spherical in shape with a narrow size distribution. It is likely that the polymer network stabilized the nanoparticles. It was determined that the hydrogel network structure can control the size and shape of the nanoparticles. The hydrogel/silver nanohybrids were characterized by swelling degree, Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM). Antibacterial activity against Staphylococcus aureus was evaluated, confirming antimicrobial action of the encapsulated silver nanoparticles into the hydrogels.

In-Silico Design, Synthesis and Evaluation of a Nanostructured Hydrogel as a Dimethoate Removal Agent.

This study describes the in-silico design, synthesis, and evaluation of a cross-linked PVA hydrogel (CLPH) for the absorption of organophosphorus pesticide dimethoate from aqueous solutions. The crosslinking effectiveness of 14 dicarboxilic acids was evaluated through in-silico studies using semiempirical quantum mechanical calculations. According to the theoretical studies, the nanopore of PVA cross-linked with malic acid (CLPH-MA) showed the best interaction energy with dimethoate. Later, using all-atom molecular dynamics simulations, three hydrogels with different proportions of PVA:MA (10:2, 10:4, and 10:6) were used to evaluate their interactions with dimethoate. These results showed that the suitable crosslinking degree for improving the affinity for the pesticide was with 20% (W%) of the cross-linker. In the experimental absorption study, the synthesized CLPH-MA20 recovered 100% of dimethoate from aqueous solutions. Therefore, the theoretical data were correlated with the experimental studies. Surface morphology of CLPH-MA20 by Scanning Electron Microscopy (SEM) was analyzed. In conclusion, the ability of CLPH-MA20 to remove dimethoate could be used as a technological alternative for the treatment of contaminated water.

Rational Development of a Novel Hydrogel as a pH-Sensitive Controlled Release System for Nifedipine.

This work depicts the rational development (in-silico design, synthesis, characterization and in-vitro evaluation) of polyvinyl alcohol hydrogels (PVAH) cross-linked with maleic acid (MA) and linked to γ-cyclodextrin molecules (γ-CDPVAHMA) as systems for the controlled and sustained release of nifedipine (NFD). Through computational studies, the structural blocks (PVA chain + dicarboxylic acid + γ-CD) of 20 different hydrogels were evaluated to test their interaction energies (ΔE) with NFD. According to the ΔE obtained, the hydrogel cross-linked with maleic acid was selected. To characterize the intermolecular interactions between NFD and γ-CDPVAHMA, molecular dynamics simulation studies were carried out. Experimentally, three hydrogel formulations with different proportions of γ-CD (2.43%, 3.61% and 4.76%) were synthesized and characterized. Both loading and release of NFD from the hydrogels were evaluated at acid and basic pH. The computational and experimental results show that γ-CDs linked to the hydrogels were able to form 1:1 inclusion complexes with NFD molecules. Finally, γ-CDPVAHMA-3 demonstrated to be the best pH-sensitive release platform for nifedipine. Its effectiveness could significantly reduce the adverse effects caused by the anticipated release of NFD in the stomach of patients.

Rational Design, Synthesis and Evaluation of γ-CD-Containing Cross-Linked Polyvinyl Alcohol Hydrogel as a Prednisone Delivery Platform.

This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN.

Simplified HPLC methodology for quantifying biological pterins by selective oxidation.

Tetrahydrobiopterin (BH4) has become a potential therapeutic tool to treat cardiovascular diseases, since it is an essential cofactor of nitric oxide synthase. In order to quantify the amount of BH4 and its related biopterins, a procedure that involves differential oxidation is currently used, which measures biopterin (the product of the oxidation of BH4 and BH2) at two different pH conditions to calculate the quantity of BH2 and BH4, using high performance liquid chromatography (HPLC). In this work, a method was established in order to quantify BH4 and BH2 by adapting previously described procedures. Several chromatographic conditions were evaluated to define the most convenient methodology. Four types of mobile phases and two different analytical columns were used for HPLC. Additionally, calibration curves were made in acid and basic pH compatible with the differential oxidation method. Each method was suitable for quantification purposes, but the choice was based on an economic factor. The selected condition was a mobile phase of 95% water/5% methanol using a C18 column at 35°C at a flow rate of 0.9mL/min. Then, it was calculated the recovery rate, which was about 80% using the chosen method. The aim of this work was to establish a simplified method of differential oxidation, compatible with matrixes such as cardiac tissue in order to facilitate the assessment of the BH4/BH2 ratio in biological samples.

High-Intensity Exercise Reduces Cardiac Fibrosis and Hypertrophy but Does Not Restore the Nitroso-Redox Imbalance in Diabetic Cardiomyopathy.

Diabetic cardiomyopathy refers to the manifestations in the heart as a result of altered glucose homeostasis, reflected as fibrosis, cellular hypertrophy, increased oxidative stress, and apoptosis, leading to ventricular dysfunction. Since physical exercise has been indicated as cardioprotective, we tested the hypothesis that high-intensity exercise training could reverse the cardiac maladaptations produced by diabetes. For this, diabetes was induced in rats by a single dose of alloxan. Diabetic rats were randomly assigned to a sedentary group or submitted to a program of exercise on a treadmill for 4 weeks at 80% of maximal performance. Another group of normoglycemic rats was used as control. Diabetic rat hearts presented cardiomyocyte hypertrophy and interstitial fibrosis. Chronic exercise reduced both parameters but increased apoptosis. Diabetes increased the myocardial levels of the mRNA and proteins of NADPH oxidases NOX2 and NOX4. These altered levels were not reduced by exercise. Diabetes also increased the level of uncoupled endothelial nitric oxide synthase (eNOS) that was not reversed by exercise. Finally, diabetic rats showed a lower degree of phosphorylated phospholamban and reduced levels of SERCA2 that were not restored by high-intensity exercise. These results suggest that high-intensity chronic exercise was able to reverse remodeling in the diabetic heart but was unable to restore the nitroso-redox imbalance imposed by diabetes.

Reconstrucción de proceso alveolar maxilar con injerto autólogo de cresta iliaca / Reconstruction of maxillary alveolar process with iliac crest autologous graft

El caso clínico que se muestra ejemplifica la conjunción de múltiples técnicas quirúrgicas con el objetivo de rehabilitar protésicamente a un paciente desdentado, para el tratamiento del maxilar superior atrófico con injerto autólogo de cresta iliaca anterior tipo onlay. Se trata de paciente del sexo femenino de 60 años de edad, la cual presenta un proceso alveolar atrófico tipo IV de Cawood y Howell, por lo que se realiza la conservación y reconstrucción de proceso alveolar con injerto autólogo de cresta iliaca.

The clinical case presented in this article illustrates the combination of multiple surgical techniques geared to the prosthetic rehabilitation of an edentulous patient for the treatment of an atrophic upper jaw with an onlay type iliac crest autologous graft. Treated patient was a 60 year old female presenting a type IV Cawood and Howell atrophic alveolar process. Therefore, treatment conducted was reconstruction of the alveolar process with an iliac crest autologous graft.

A controlled trial of pravastatin vs probucol in the treatment of primary hypercholesterolemia

Es un estudio comparativo de la seguridad, tolerabilidad y eficacia del inhibidor de HMGCoA reductasa, pravastatin, y probucol en el tratamiento de pacientes con hipercolesterolemia primaria, utilizando un diseño doble ciego, controlado con medicamento activo, con distribución aleatoria de los tratamientos, utilizando placebos de ambas drogas. Se incluyeron pacientes con LDL-C > de 150 mg/dL y triglicéridos < 350 mg/dL después de un mínimo de seis semanas recibiendo placebo y una dieta fase I de la American Heart Association. Los pacientes relacionados fueron asignados aleatoriamente para recibir pravastatin 40 mg diarios por la noche o probucol 500 mg cada 12 horas y también recibieron los placebos idénticos de las drogas en estudio. El periodo de tratamiento con medicación activa duró 16 semanas: durante este periodo, los pacientes fueron vistos a las 4, 8, 12 y 16 semanas. No se demostraron diferencias significativas entre los valores basales de ambos grupos. Los valores de colesterol total y LDL-C fueron significativamente menores con pravastatin que con probucol. Se observó un aumento promedio de HDL-C con pravastatin y probucol, fueron bien tolerados: sólo se observaron cambios clínicos y de laboratorio mínimos, ninguno de los cuales fue considerado relacionado con las drogas estudiadas. No se observaron cambios significativos en el cristalino. El estudio muestra una superioridad clara del pravastatin sobre el probucol basada en un cambio más favorable en el perfil de lípidos