Using Redox Proteomics to Gain New Insights into Neurodegenerative Disease and Protein Modification.

Antioxidant defenses in biological systems ensure redox homeostasis, regulating baseline levels of reactive oxygen and nitrogen species (ROS and RNS). Oxidative stress (OS), characterized by a lack of antioxidant defenses or an elevation in ROS and RNS, may cause a modification of biomolecules, ROS being primarily absorbed by proteins. As a result of both genome and environment interactions, proteomics provides complete information about a cell's proteome, which changes continuously. Besides measuring protein expression levels, proteomics can also be used to identify protein modifications, localizations, the effects of added agents, and the interactions between proteins. Several oxidative processes are frequently used to modify proteins post-translationally, including carbonylation, oxidation of amino acid side chains, glycation, or lipid peroxidation, which produces highly reactive alkenals. Reactive alkenals, such as 4-hydroxy-2-nonenal, are added to cysteine (Cys), lysine (Lys), or histidine (His) residues by a Michael addition, and tyrosine (Tyr) residues are nitrated and Cys residues are nitrosylated by a Michael addition. Oxidative and nitrosative stress have been implicated in many neurodegenerative diseases as a result of oxidative damage to the brain, which may be especially vulnerable due to the large consumption of dioxygen. Therefore, the current methods applied for the detection, identification, and quantification in redox proteomics are of great interest. This review describes the main protein modifications classified as chemical reactions. Finally, we discuss the importance of redox proteomics to health and describe the analytical methods used in redox proteomics.

The Relationship between Clock Genes, Sirtuin 1, and Mitochondrial Activity in Head and Neck Squamous Cell Cancer: Effects of Melatonin Treatment.

The circadian clock is a regulatory system, with a periodicity of approximately 24 h, which generates rhythmic changes in many physiological processes, including mitochondrial activity. Increasing evidence links chronodisruption with aberrant functionality in clock gene expression, resulting in multiple diseases such as cancer. Melatonin, whose production and secretion oscillates according to the light-dark cycle, is the principal regulator of clock gene expression. In addition, the oncostatic effects of melatonin correlate with an increase in mitochondrial activity. However, the direct links between circadian clock gene expression, mitochondrial activity, and the antiproliferative effects of melatonin in cancers, including head and neck squamous cell carcinoma (HNSCC), remain largely unknown. In this study, we analyzed the effects of melatonin on HNSCC cell lines (Cal-27 and SCC9), which were treated with 500 and 1000 µM melatonin. We found that the antiproliferative effect of melatonin is not mediated by the Bmal1 clock gene. Additionally, high doses of melatonin were observed to result in resynchronization of oscillatory circadian rhythm genes (Per2 and Sirt1). Surprisingly, the resynchronizing effect of melatonin on Per2 and Sirt1 did not produce alterations in the oscillation of mitochondrial respiratory activity. These results increase our understanding of the possible antiproliferative mechanisms in melatonin in the treatment of head and neck squamous cell carcinoma and suggest that its antiproliferative effects are independent of clock genes but are directly related to mitochondrial activity.

Intratumoral injection of melatonin enhances tumor regression in cell line-derived and patient-derived xenografts of head and neck cancer by increasing mitochondrial oxidative stress.

Head and neck squamous cell carcinoma present a high mortality rate. Melatonin has been shown to have oncostatic effects in different types of cancers. However, inconsistent results have been reported for in vivo applications. Consequently, an alternative administration route is needed to improve bioavailability and establish the optimal dosage of melatonin for cancer treatment. On the other hand, the use of patient-derived tumor models has transformed the field of drug research because they reflect the heterogeneity of patient tumor tissues. In the present study, we explore mechanisms for increasing melatonin bioavailability in tumors and investigate its potential as an adjuvant to improve the therapeutic efficacy of cisplatin in the setting of both xenotransplanted cell lines and primary human HNSCC. We analyzed the effect of two different formulations of melatonin administered subcutaneously or intratumorally in Cal-27 and SCC-9 xenografts and in patient-derived xenografts. Melatonin effects on tumor mitochondrial metabolism was also evaluated as well as melatonin actions on tumor cell migration. In contrast to the results obtained with the subcutaneous melatonin, intratumoral injection of melatonin drastically inhibited tumor progression in HNSCC-derived xenografts, as well as in patient-derived xenografts. Interestingly, intratumoral injection of melatonin potentiated CDDP effects, decreasing Cal-27 tumor growth. We demonstrated that melatonin increases ROS production and apoptosis in tumors, targeting mitochondria. Melatonin also reduces migration capacities and metastasis markers. These results illustrate the great clinical potential of intratumoral melatonin treatment and encourage a future clinical trial in cancer patients to establish a proper clinical melatonin treatment.

Patient-derived tumor models in cancer research: Evaluation of the oncostatic effects of melatonin.

The development of new anticancer therapies tends to be very slow. Although their impact on potential candidates is confirmed in preclinical studies, ∼95 % of these new therapies are not approved when tested in clinical trials. One of the main reasons for this is the lack of accurate preclinical models. In this context, there are different patient-derived models, which have emerged as a powerful oncological tool: patient-derived xenografts (PDXs), patient-derived organoids (PDOs), and patient-derived cells (PDCs). Although all these models are widely applied, PDXs, which are created by engraftment of patient tumor tissues into mice, is considered more reliable. In fundamental research, the PDX model is used to evaluate drug-sensitive markers and, in clinical practice, to select a personalized therapeutic strategy. Melatonin is of particular importance in the development of innovative cancer treatments due to its oncostatic impact and lack of adverse effects. However, the literature regarding the oncostatic effect of melatonin in patient-derived tumor models is scant. This review aims to describe the important role of patient-derived models in the development of anticancer treatments, focusing, in particular, on PDX models, as well as their use in cancer research. This review also summarizes the existing literature on the anti-tumoral effect of melatonin in patient-derived models in order to propose future anti-neoplastic clinical applications.

Chronodisruption and Loss of Melatonin Rhythm, Associated with Alterations in Daily Motor Activity and Mitochondrial Dynamics in Parkinsonian Zebrafish, Are Corrected by Melatonin Treatment.

Beyond sleep/wake, clock genes regulate the daily rhythms of melatonin production, motor activity, innate immunity, and mitochondrial dynamics, among others. All these rhythms are affected in Parkinson's disease (PD), suggesting that chronodisruption may be an early stage of the disease. The aim of this study was to evaluate the connection between clock genes and these rhythms in PD, and whether melatonin administration reestablished the normal clock function. Parkinsonism was induced with 600 µM MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) in 24-120 h post fertilization (hpf) zebrafish embryos and melatonin was administered at a dose of 1 µM. Day-night melatonin rhythm disappeared in MPTP-treated embryos, which showed an advance in the activity phase in parallel with changes in the rhythm of clock genes. An alteration in the fission-to-fusion mitochondrial dynamics was also detected in parkinsonian embryos, increasing the former and leading to apoptosis. Melatonin administration to MPTP-treated embryos fully restored the circadian system, including the rhythms of clock genes, motor activity, melatonin rhythm, and mitochondrial dynamics, and decreasing apoptosis. Because clock-controlled rhythms such as sleep/wake alterations are early events in PD, the data here reported may point to chronodisruption as one initial pathophysiological event of the disease.

Role of Melatonin in Cancer: Effect on Clock Genes.

The circadian clock is a regulatory system, with a periodicity of approximately 24 h, that generates rhythmic changes in many physiological processes. Increasing evidence links chronodisruption with aberrant functionality in clock gene expression, resulting in multiple diseases, including cancer. In this context, tumor cells have an altered circadian machinery compared to normal cells, which deregulates the cell cycle, repair mechanisms, energy metabolism and other processes. Melatonin is the main hormone produced by the pineal gland, whose production and secretion oscillates in accordance with the light:dark cycle. In addition, melatonin regulates the expression of clock genes, including those in cancer cells, which could play a key role in the numerous oncostatic effects of this hormone. This review aims to describe and clarify the role of clock genes in cancer, as well as the possible mechanisms of the action of melatonin through which it regulates the expression of the tumor's circadian machinery, in order to propose future anti-neoplastic clinical treatments.

Melatonin drives apoptosis in head and neck cancer by increasing mitochondrial ROS generated via reverse electron transport.

The oncostatic effects of melatonin correlate with increased reactive oxygen species (ROS) levels, but how melatonin induces this ROS generation is unknown. In the present study, we aimed to elucidate the two seemingly opposing actions of melatonin regarding its relationship with free radicals. We analyzed the effects of melatonin on head and neck squamous cell carcinoma cell lines (Cal-27 and SCC-9), which were treated with 0.5 or 1 mM melatonin. We further examined the potential effects of melatonin to induce ROS and apoptosis in Cal-27 xenograft mice. Here we report that melatonin mediates apoptosis in head and neck cancer by driving mitochondrial reverse electron transport (RET) to induce ROS production. Melatonin-induced changes in tumoral metabolism led to increased mitochondrial activity, which, in turn, induced ROS-dependent mitochondrial uncoupling. Interestingly, mitochondrial complex inhibitors, including rotenone, abolished the ROS elevation indicating that melatonin increased ROS generation via RET. Melatonin also increased membrane potential and CoQ10 H2 /CoQ10 ratio to elevate mitochondrial ROS production, which are essential conditions for RET. We found that genetic manipulation of cancer cells with alternative oxidase, which transfers electrons from QH2 to oxygen, inhibited melatonin-induced ROS generation, and apoptosis. RET restored the melatonin-induced oncostatic effect, highlighting the importance of RET as the site of ROS production. These results illustrate that RET and ROS production are crucial factors in melatonin's effects in cancer cells and establish the dual effect of melatonin in protecting normal cells and inducing apoptosis in cancer cells.

Understanding the Mechanism of Action of Melatonin, Which Induces ROS Production in Cancer Cells.

Reactive oxygen species (ROS) constitute a group of highly reactive molecules that have evolved as regulators of important signaling pathways. In this context, tumor cells have an altered redox balance compared to normal cells, which can be targeted as an antitumoral therapy by ROS levels and by decreasing the capacity of the antioxidant system, leading to programmed cell death. Melatonin is of particular importance in the development of innovative cancer treatments due to its oncostatic impact and lack of adverse effects. Despite being widely recognized as a pro-oxidant molecule in tumor cells, the mechanism of action of melatonin remains unclear, which has hindered its use in clinical treatments. The current review aims to describe and clarify the proposed mechanism of action of melatonin inducing ROS production in cancer cells in order to propose future anti-neoplastic clinical applications.

The Zebrafish, an Outstanding Model for Biomedical Research in the Field of Melatonin and Human Diseases.

The zebrafish has become an excellent model for the study of human diseases because it offers many advantages over other vertebrate animal models. The pineal gland, as well as the biological clock and circadian rhythms, are highly conserved in zebrafish, and melatonin is produced in the pineal gland and in most organs and tissues of the body. Zebrafish have several copies of the clock genes and of aanat and asmt genes, the latter involved in melatonin synthesis. As in mammals, melatonin can act through its membrane receptors, as with zebrafish, and through mechanisms that are independent of receptors. Pineal melatonin regulates peripheral clocks and the circadian rhythms of the body, such as the sleep/wake rhythm, among others. Extrapineal melatonin functions include antioxidant activity, inducing the endogenous antioxidants enzymes, scavenging activity, removing free radicals, anti-inflammatory activity through the regulation of the NF-κB/NLRP3 inflammasome pathway, and a homeostatic role in mitochondria. In this review, we introduce the utility of zebrafish to analyze the mechanisms of action of melatonin. The data here presented showed that the zebrafish is a useful model to study human diseases and that melatonin exerts beneficial effects on many pathophysiological processes involved in these diseases.

Root Cause Analysis of Na131I Contamination.

Establishing a cause-and-effect relationship for an adverse event is one of the key steps in preventing them and involves multiple people, resources, and steps, thus requiring a root cause analysis. Here, we describe a root cause analysis performed in the nuclear medicine department for an event involving Na131I contamination. Oral administration of Na131I in a capsule minimizes the risk of contamination and spills. However, the patient must be able to swallow a capsule. Na131I in capsule form is currently in widespread use for treatment of hyperthyroidism and thyroid cancer. Na131I in liquid form is rarely available immediately on demand and must be ordered at least 24-48 h in advance of the planned administration. The events leading to the incident, immediate remedial steps taken, and subsequent root cause analysis are described. The corrective actions taken after the root cause analysis, as well as the subsequent effectiveness of these actions, are mentioned. There may be one or multiple causes for an adverse event. It is important to identify the root cause. Corrective actions derived from the root cause can help prevent similar adverse events in the future. Therapeutic procedures in nuclear medicine involve unsealed radioactive sources, further adding a separate layer of immediate steps and reporting to the root cause analysis itself.

The Impact of Melatonin and NLRP3 Inflammasome on the Expression of microRNAs in Aged Muscle.

Muscular aging is a complex process and underlying physiological mechanisms are not fully clear. In recent years, the participation of the NF-kB pathway and the NLRP3 inflammasome in the chronic inflammation process that accompanies the skeletal muscle's aging has been confirmed. microRNAs (miRs) form part of a gene regulatory machinery, and they control numerous biological processes including inflammatory pathways. In this work, we studied the expression of four miRs; three of them are considered as inflammatory-related miRs (miR-21, miR-146a, and miR-223), and miR-483, which is related to the regulation of melatonin synthesis, among other targets. To investigate the changes of miRs expression in muscle along aging, the impact of inflammation, and the role of melatonin in aged skeletal muscle, we used the gastrocnemius muscle of wild type (WT) and NLRP3-knockout (NLRP3-) mice of 3, 12, and 24 months-old, with and without melatonin supplementation. The expression of miRs and pro-caspase-1, caspase-3, pro-IL-1ß, bax, bcl-2, and p53, was investigated by qRT-PCR analysis. Histological examination of the gastrocnemius muscle was also done. The results showed that age increased the expression of miR-21 (p < 0.01), miR-146a, and miR-223 (p < 0.05, for both miRs) in WT mice, whereas the 24-months-old mutant mice revealed decline of miR-21 and miR-223 (p < 0.05), compared to WT age. The lack of NLRP3 inflammasome also improved the skeletal muscle fibers arrangement and reduced the collagen deposits compared with WT muscle during aging. For the first time, we showed that melatonin significantly reduced the expression of miR-21, miR-146a, and miR-223 (p < 0.05 for all ones, and p < 0.01 for miR-21 at 24 months old) in aged WT mice, increased miR-223 in NLRP3- mice (p < 0.05), and induced miR-483 expression in both mice strains, this increase being significant at 24 months of age.

Melatonin Targets Metabolism in Head and Neck Cancer Cells by Regulating Mitochondrial Structure and Function.

Metabolic reprogramming, which is characteristic of cancer cells that rapidly adapt to the hypoxic microenvironment and is crucial for tumor growth and metastasis, is recognized as one of the major mechanisms underlying therapeutic resistance. Mitochondria, which are directly involved in metabolic reprogramming, are used to design novel mitochondria-targeted anticancer agents. Despite being targeted by melatonin, the functional role of mitochondria in melatonin's oncostatic activity remains unclear. In this study, we aim to investigate the role of melatonin in mitochondrial metabolism and its functional consequences in head and neck cancer. We analyzed the effects of melatonin on head and neck squamous cell carcinoma (HNSCC) cell lines (Cal-27 and SCC-9), which were treated with 100, 500, and 1500 µM of melatonin for 1, 3, and 5 days, and found a connection between a change of metabolism following melatonin treatment and its effects on mitochondria. Our results demonstrate that melatonin induces a shift to an aerobic mitochondrial metabolism that is associated with changes in mitochondrial morphology, function, fusion, and fission in HNSCC. We found that melatonin increases oxidative phosphorylation (OXPHOS) and inhibits glycolysis in HNSCC, resulting in increased ROS production, apoptosis, and mitophagy, and decreased cell proliferation. Our findings highlight new molecular pathways involved in melatonin's oncostatic activity, suggesting that it could act as an adjuvant agent in a potential therapy for cancer patients. We also found that high doses of melatonin, such as those used in this study for its cytotoxic impact on HNSCC cells, might lead to additional effects through melatonin receptors.

Optimizing forest road planning in a sustainable forest management area in the Brazilian Amazon.

The construction of forest roads in Brazilian Amazon is costly and has a significant environmental impact. Several practices and principles must be observed to comply with legislation, to preserve the remaining forest, and to ensure sustainable exploitation. Road planning is complex in this context, based on the number of aspects and variables that must be considered. This research aimed to evaluate computational methods' effectiveness in planning forest roads, optimizing resources to reduce damage to the remaining forest, compared to traditional planning methods. The study area was a native forest under a sustainable forest management regime located in municipalities of Terra Santa and Oriximiná, in Pará, in Brazilian Amazon. Data obtained from area made it possible formulate six instances of different sizes. A binary integer linear programming model was used, solved using CPLEX software, and Dijkstra, Bellman-Ford, Dial, and D'Esopo-Pape shortest path algorithm, implemented in C programming language. During processing of instances, the time taken to obtain the solution increased according to size of instance, however, time difference was not significant. Among the evaluated algorithms, the D'Esopo-Pape algorithm showed the best performance. The evaluated methods were effective in obtaining an optimal solution for proposed forest road planning. The solutions obtained using computational methods more effectively considered the restrictions associated with sustainable forest management, in contrast to those derived from the traditional planning by forestry company.

Importance of suspended particulate organic matter in the diet of Nephrops norvegicus (Linnaeus, 1758).

The extent to which commercially important Nephrops norvegicus lobsters feed on particulates in the wild is unknown, even though this could be an important way for burrow-dwelling females to avoid starvation during the long breeding season. This was investigated using δ13C and δ15N isotopic signatures in tissues with long and short turnover rates to provide diet discrimination and compare this between males and females. Secondary objectives examined size-related differences and calculated the trophic position based on the new results. Almost half the diet (47%) was made up of suspended particulate organic matter (POMsusp) alone. Fish was another important item in the diet, with plankton and invertebrate sources coming much lower down in dietary importance. Significantly more suspension feeding was observed in small or medium sized individuals than large ones in both sexes. However, there were no sex-related patterns, despite females being restricted to burrows for part of the analysis period. Female diet was almost identical to males and POMsusp comprised a large component of the diet in both sexes. The trophic position was estimated at 2.94 ± 0.16 (mean ± SD), which was at the lower end of the range reported in previous studies (2.60 to 4.32).

Protective Effects of Melatonin on the Skin: Future Perspectives.

When exposed to hostile environments such as radiation, physical injuries, chemicals, pollution, and microorganisms, the skin requires protective chemical molecules and pathways. Melatonin, a highly conserved ancient molecule, plays a crucial role in the maintenance of skin. As human skin has functional melatonin receptors and also acts as a complete system that is capable of producing and regulating melatonin synthesis, melatonin is a promising candidate for its maintenance and protection. Below, we review the studies of new metabolic pathways involved in the protective functions of melatonin in dermal cells. We also discuss the advantages of the topical use of melatonin for therapeutic purposes and skin protection. In our view, endogenous intracutaneous melatonin production, together with topically-applied exogenous melatonin and its metabolites, represent two of the most potent defense systems against external damage to the skin.

Determinación de clorhidrato de clembuterol en orina de bovinos en tres rastros municipales del estado de México / Determination of Clenbuterol Hydrochloride in Bovine Urine in Three Municipal Slaughterhouses of the State of Mexico / Determinação de cloridrato de clenbuterol em urina de bovinos em três trilhas municipais do estado do México

Resumen El objetivo del presente trabajo fue determinar el porcentaje de bovinos para abasto positivos a clorhidrato de clembuterol (CCL), con base en muestras de orina de bovinos sacrificados en 3 rastros del estado de México. Para esto se colectaron muestras en los rastros municipales de Toluca (59), Ixtlahuaca (52) y Atlacomulco (40), y se obtuvo un total de 151 muestras. El análisis de las muestras se realizó a través de la prueba de ELISA y para el reporte de resultados se utilizó estadística descriptiva. De las muestras analizadas 105 fueron positivas (69,53 %), por rastro la positividad, fue de 48, 30 y 27 respectivamente. Al establecer diferentes rangos de concentración a CCL, en el rango de 200 a 1999 pg g-1 se ubicaron 46 muestras; 6 muestras, en el rango de 2000 a 3525 pg g-1; 3, en el rango de 3526 a 5050 pg g-1; 1 muestra, entre 5051 y 6575 pg g-1, y 95 se ubicaron entre 6575 y >8100 pg g-1. El rastro con mayor porcentaje de positividad fue el de Toluca, con base en los rangos establecidos, y las concentraciones más elevadas también se observaron en el mismo rastro. El límite mínimo de detección de CCL de 2000 pg g-1 permite considerar que, con base tanto en la concentración como en su cinética, las cantidades detectadas en el estudio sirven como un indicador importante de residualidad a través de este tipo de muestra.

Abstract The present work aimed to determine the percentage of bovines that tested positive for clenbuterol hydrochloride (CCL), based on urine samples of cattle slaughtered in 3 slaughterhouses of the State of Mexico. To the effect, samples were collected in the municipal slaughterhouses of Toluca (59), Ixtlahuaca (52), and Atlacomulco (40), resulting in a total of 151 samples. Sample analysis was carried out using the ELISA test, and descriptive statistics were used to report the results. 105 of the analyzed samples were positive (69.53%); by slaughterhouse, positivity was 48, 30, and 27, respectively. When establishing different ranges of CCL concentration, 46 samples were in the range of 200 to 1999 pg g-1; 6 samples were in the range of 2000 to 3525 pg g-1; 3 were in the range of 3526 to 5050 pg g-1; 1 sample was between 5051 and 6575 pg g-1, and 95 samples were between 6575 and >8100 pg g-1. The slaughterhouse with the highest percentage of positivity was that of Toluca, based on the established ranges, and the highest concentrations were also observed there. The minimum limit for the detection of CCL (2000 pg g-1) allows considering that, based on both concentration and kinetics, the quantities detected in the study serve as an important indicator of residuality in this type of sample.

Resumo O objetivo do presente trabalho foi determinar a porcentagem de bovinos para fornecimento, positivos ao cloridrato de Clenbuterol (CCL), baseados em amostras de urina de bovinos abatidos em três trilhas do estado de México. Para isso, foram coletadas amostras nas trilhas municipais de Toluca (59), Ixtlahuaca (52) e Atlacomulco (40), e obtivera-se um total de 151 amostras. A análise das amostras realizou-se através do teste de ELISA e para o relatório de resultados foi usada estatística descritiva. Das amostras analisadas 105 foram positivas (69,53 %), pelo traço a positividade foi de 48, 30 e 27 respetivamente. Ao estabelecer diferentes faixas de concentração a CCL, 46 amostras foram colocadas na faixa de 200 a 1999 pg g-1; 6 amostras na faixa de 2000 a 3525 pg g-1; 3 na faixa de 3526 a 5050 pg g-1; 1 amostra entre 5051 e 6575 pg g-1, e 95 entre 6575 e >8100 pg g-1. A trilha com maior porcentagem de positividade foi a de Toluca, baseada nas faixas estabelecidas e as concentrações mais altas observaram-se na mesma trilha. O limite mínimo de detecção de CCL de 2000 pg g-1 permite considerar que, baseado na concentração e na cinética, as quantidades detectadas no estudo servem como indicador importante de residualidade através deste tipo de amostra.

Melatonin Enhances Cisplatin and Radiation Cytotoxicity in Head and Neck Squamous Cell Carcinoma by Stimulating Mitochondrial ROS Generation, Apoptosis, and Autophagy.

Head and neck cancer is the sixth leading cancer by incidence worldwide. Unfortunately, drug resistance and relapse are the principal limitations of clinical oncology for many patients, and the failure of conventional treatments is an extremely demoralizing experience. It is therefore crucial to find new therapeutic targets and drugs to enhance the cytotoxic effects of conventional treatments without potentiating or offsetting the adverse effects. Melatonin has oncostatic effects, although the mechanisms involved and doses required remain unclear. The purpose of this study is to determine the precise underlying mitochondrial mechanisms of melatonin, which increase the cytotoxicity of oncological treatments, and also to propose new melatonin treatments in order to alleviate and reverse radio- and chemoresistant processes. We analyzed the effects of melatonin on head and neck squamous cell carcinoma (HNSCC) cell lines (Cal-27 and SCC-9), which were treated with 0.1, 0.5, 1, and 1.5 mM melatonin combined with 8 Gy irradiation or 10 µM cisplatin. Clonogenic and MTT assays, as well as autophagy and apoptosis, involving flow cytometry and western blot, were performed in order to determine the cytotoxic effects of the treatments. Mitochondrial function was evaluated by measuring mitochondrial respiration, mtDNA content (RT-PCR), and mitochondrial mass (NAO). ROS production, antioxidant enzyme activity, and GSH/GSSG levels were analyzed using a fluorometric method. We show that high concentrations of melatonin potentiate the cytotoxic effects of radiotherapy and CDDP in HNSCC, which are associated with increased mitochondrial function in these cells. In HNSCC, melatonin induces intracellular ROS, whose accumulation plays an upstream role in mitochondria-mediated apoptosis and autophagy. Our findings indicate that melatonin, at high concentrations, combined with cisplatin and radiotherapy to improve its effectiveness, is a potential adjuvant agent.

Influence of Asphaltenes in the Properties of Liquid-Liquid Interface between Water and Linear Saturated Hydrocarbons.

Molecular dynamics simulations have been performed on the interface between linear saturated hydrocarbons and water in the presence of an asphaltene molecule by measuring the properties such as mean square displacement, radial distribution function, density profile using ave/spatial command, and interfacial tension (IFT) by OPLS and TIP3P FF (force fields). The box of simulation contained one particle of asphaltene, 100 linear saturated hydrocarbons molecules, and 300 water molecules in mixture with interfacial appropriate positioning. The main results show that a small amount of asphaltene in the interface does not significantly alter the data of IFT and that the aliphatic and aromatic groups have preferred orientation.

Diagnostic performance of the quantification of myocardium at risk from MPI SPECT/CTA 2G fusion for detecting obstructive coronary disease: A multicenter trial.

BACKGROUND: The effective non-invasive identification of coronary artery disease (CAD) and its proper referral for invasive treatment are still unresolved issues. We evaluated our quantification of myocardium at risk (MAR) from our second generation 3D MPI/CTA fusion framework for the detection and localization of obstructive coronary disease. METHODS: Studies from 48 patients who had rest/stress MPI, CTA, and ICA were analyzed from 3 different institutions. From the CTA, a 3D biventricular surface of the myocardium with superimposed coronaries was extracted and fused to the perfusion distribution. Significant lesions were identified from CTA readings and positioned on the fused display. Three estimates of MAR were computed on the 3D LV surface on the basis of the MPI alone (MARp), the CTA alone (MARa), and the fused information (MARf). The extents of areas at risk were used to generate ROC curves using ICA anatomical findings as reference standard. RESULTS: Areas under the ROC curve (AUC) for CAD detection using MARf was 0.88 (CI = 0.75-0.95) and for MARp and MARa were, respectively 0.82 (CI = 0.69-0.92) and 0.75 (CI = 0.60-0.86) using the ≥70% stenosis criterion. AUCs for CAD localization (all vessels) using MARf showed significantly higher performance than either MARa or MARp or both. CONCLUSIONS: Using ICA as the reference standard, MAR as the quantitative parameter, and AUC to measure diagnostic performance, MPI-CTA fusion imaging provided incremental diagnostic information compared to MPI or CTA alone for the diagnosis and localization of CAD.

Efecto del clorhidrato de clembuterol en la ganancia de peso y lesiones histológicas en ratones / Effect of clenbuterol hydrochloride on weight gain and histological lesions in mice / Efeito do cloridrato de clembuterol no aumento de peso e lesões histológicas em ratos

Resumen El clorhidrato de clembuterol (CCL) es un p-agonista promotor del crecimiento en animales para abasto, pero su uso ilícito ha generado repercusiones en salud pública. Se realizó un modelo biológico con ratones, con el objeto de evaluar el efecto del CCL sobre la ganancia de peso y las lesiones histológicas que ocasiona. Los ratones fueron alimentados con carne de conejo, que previamente fue suplementada con CCL. Treinta y cinco días posexposición se registró el peso corporal; se obtuvo la concentración muscular y sérica de CCL a través de la prueba de ELISA, y se colectaron tejidos (hígado y corazón) para análisis histopatológico. Los valores obtenidos de los animales experimentales (G1 y G2) se analizaron mediante un diseño experimental completamente al azar con dos tratamientos (n = 10), sometidos a un análisis de varianza y comparación de medias con la prueba de Tukey (p < 0,05). Se registró un incremento de peso corporal de 7 g en el G1, contra 4,0 g del G2. El peso del hígado fue de 2,58 g y 1,79, respectivamente (p < 0,05). En el G1 la concentración muscular de CCL fue 5324 pg g-1 y en suero sanguíneo de 4378 pg g-1. Solo se observaron cambios histológicos en tejidos de los ratones del G1. El hígado mostró tumefacción celular, mitosis moderada, picnosis y degeneración hidrópica; en corazón, engrosamiento de fibras, pleomorfismo e hileración nuclear. El CCL favoreció el incremento de peso en los ratones expuestos, y provocó alteraciones estructurales en hígado y corazón.

Abstract Clenbuterol hydrochloride (CLB) is a growth-promoting p-agonist in animals for supply, but its illicit use has generated repercussions on public health. A biological model with mice was developed to evaluate the effect of CLB on weight gain and histological lesions. Mice were fed rabbit meat, which was previously supplemented with CLB. Body weight was recorded 35 days post-exposure; muscular and serum concentration of CLB was obtained through the ELISA test, and tissues were collected from liver and heart for histopathological analysis. Values obtained from the experimental animals (G1 and G2) were analyzed by a completely randomized experimental design with two treatments (n = 10), subjected to an analysis of variance and comparison of means with the Tukey test (p<0.05). There was an increase of 7 g in body weight in G1, compared to 4.0 g in G2. Liver weight was 2.58 g and 1.79, respectively (p<0.05). In G1, CLB concentration in muscle was 5324 pg.g-1, and 4378 pg.g-1 in blood serum. Only histological changes were observed in the tissues of Gl mice. Liver showed cellular swelling, moderate mitosis, pyknosis and hydropic degeneration; in addition, fiber thickening, pleomorphism and nuclear atypia were observed in the heart. CLB contributed to weight gain in exposed mice and caused structural alterations in liver and heart.

Resumo O cloridrato de clembuterol (CCL) é um b-agonista promotor do crescimento em animais para abate, porém o seu uso ilícito tem gerado repercussões em saúde pública. Fezse um modelo biológico com ratos, com o objeto de avaliar o efeito do CCL sobre o ganho de peso e as lesões histológicas que ocasiona. Os ratos foram alimentados com carne de coelho, que previamente foi suplementada com CCL. Trinta e cinco dias pós-exposição se registrou o peso corporal; obteve-se a concentração muscular e sérica de CCL através da prova de ELISA, e foram coletados tecidos (fígado e coração) para análise histopatológica. Os valores obtidos dos animais experimentais (Gl e G2) foram analisados mediante um desenho experimental completamente ao acaso com dois tratamentos (n = 10), submetidos a uma análise de variações e comparação de médias com a prova de Tukey (p < 0,05). Registrou-se um aumento de peso corporal de 7 g no G1, contra 4,0 g do G2. O peso do fígado foi de 2,58 g e 1,79, respectivamente (p < 0,05). No G1 a concentração muscular de CCL foi 5324 pg g-1 e em soro sanguíneo de 4378 pg g-1. Somente foram observadas mudanças histológicas em tecidos dos ratos do G1. O fígado apresentou inchaço celular, mitose moderada, picnose e degeneração hidrópica; no coração, engrossamento de fibras, pleomorfismo e filamento nuclear. O CCL favoreceu o aumento de peso nos ratos expostos, e provocou alterações estruturais em fígado e coração.