a new strategy to revisit mycobacterial targets and repurpose old drugs

Introduction: In 2018, an estimated 377,000 people developed multidrug-resistant tuberculosis (MDR-TB), urging for new effective treatments. In the last years, it has been accepted that efflux pumps play an important role in the evolution of drug resistance. Strategies are required to mitigate the consequences of the activity of efflux pumps. Areas covered: Based upon the literature available in PubMed, up to February 2020, on the diversity of efflux pumps in Mycobacterium tuberculosis and their association with drug resistance, studies that identified efflux inhibitors and their effect on restoring the activity of antimicrobials subjected to efflux are reviewed. These support a new strategy for the development of anti-TB drugs, including efflux inhibitors, using in silico drug repurposing. Expert opinion: The current literature highlights the contribution of efflux pumps in drug resistance in M. tuberculosis and that efflux inhibitors may help to ensure the effectiveness of anti-TB drugs. However, despite the usefulness of efflux inhibitors in in vitro studies, in most cases their application in vivo is restricted due to toxicity. In a time when new drugs are needed to fight MDR-TB and extensively drug-resistant TB, cost-effective strategies to identify safer efflux inhibitors should be implemented in drug discovery programs.publishersversionpublishe

Metric variation of the tibia in the Mediterranean: implications in forensic identification

Ancestry estimation from skeletal remains is a challenging task, but essential for the creation of a complete biological profile. As such, the study of human variation between populations is important for the fields of biological and forensic anthropology, as well as medicine. Cranial and dental morphological variation have traditionally been linked to geographic affinity resulting in several methods of ancestry estimation, while the postcranial skeleton has been systematically neglected. The current study explores metric variation of the tibia in six Mediterranean populations and its validity in estimating ancestry in the Mediterranean. The study sample includes 909 individuals (470 males and 439 females) from Cyprus, Greece, Italy, Spain, Portugal and Turkey. The sample was divided in two subsamples: a reference and a validation sample. Multinomial regression models were created based on the reference sample and then applied to validation sample. The first model used three variables and resulted in 57% and 56% accuracy for the two samples respectively, while the second model (6 variables) resulted in 80% and 74% respectively. Classification between groups ranged from 28% to 95% for the reference sample and from 15% to 91% for the validation sample. The highest classification accuracy was noted for the Greek sample (95% and 90% for the reference and validation sample respectively), followed by the Turkish sample (74% and 78% respectively). The Spanish, Portuguese and Italian samples presented greater morphological overlap which resulted in lower classification accuracies. The results indicate that although the tibia presents considerable variation amongst neighbour populations is not suitable as a sole skeletal element to separate all groups successfully. A combination of different skeletal elements may be required in order to achieve the levels of reliability required for forensic applications

Mechanism of Antifungal Activity by 5-Aminoimidazole-4-Carbohydrazonamide Derivatives against Candida albicans and Candida krusei

Systemic mycoses are one major cause of morbidity/mortality among immunocompromised/debilitated individuals. Studying the mechanism of action is a strategy to develop safer/potent antifungals, warning resistance emergence. The major goal of this study was to elucidate the mechanism of action of three (Z)-5-amino-N’-aryl-1-methyl-1H-imidazole-4-carbohydrazonamides (2h, 2k, 2l) that had previously demonstrated strong antifungal activity against Candida krusei and C. albicans ATCC strains. Activity was confirmed against clinical isolates, susceptible or resistant to fluconazole by broth microdilution assay. Ergosterol content (HPLC-DAD), mitochondrial dehydrogenase activity (MTT), reactive oxygen species (ROS) generation (flow cytometry), germ tube inhibition and drug interaction were evaluated. None of the compounds inhibited ergosterol synthesis. Ascorbic acid reduced the antifungal effect of compounds and significantly decreased ROS production. The metabolic viability of C. krusei was significantly reduced for values of 2MIC. Compounds 2h and 2k caused a significant increase in ROS production for MIC values while for 2l a significant increase was only observed for concentrations above MIC. ROS production seems to be involved in antifungal activity and the higher activity against C. krusei versus C. albicans may be related to their unequal sensitivity to different ROS. No synergism with fluconazole or amphotericin was observed, but the association of 2h with fluconazole might be valuable due to the significant inhibition of the dimorphic transition, a C. albicans virulence mechanism.This research was partially supported by national funds through FCT—Foundation for Sci ence and Technology within the scope of UID/Multi/04546/2019, UIDB/04423/2020, UIDB/50006/2020, UID/QUI/00686/2020

Estudo experimental sobre decomposição cadavérica usando carcaças de Sus scrofa domestica

CRAVO, Liliana Alexandra Simões - Estudo experimental sobre decomposição cadavérica usando carcaças de Sus scrofa domestica. Coimbra : [s.n.], 2015. Dissertação de Mestrado em Antropologia.As diferentes características ambientais vão influenciar a decomposição de um cadáver consoante o seu local de deposição, seja ele inumado ou exposto à superfície. Estas condições ambientais podem modificar todo o processo, acelerando-o ou mesmo impedindo a sua continuação. Regra geral, o enterramento de um cadáver protege-o de vários agentes tafonómicos destrutivos. A estimativa do PMI (intervalo postmortem) é fundamental para a reconstrução dos eventos que rodeiam a morte de um indivíduo. Apesar de representar uma questão pertinente em questões legais, a sua estimativa é de particular dificuldade. Isto é confirmado pela falta de métodos fiáveis, especialmente quando nos referimos ao período de pós esqueletização. O presente estudo pretende contribuir para um melhor entendimento do processo de decomposição em clima Mediterrâneo bem como dos vários fatores extrínsecos que afetam o cadáver consoante o local de deposição. Para tal, utilizaram-se quatro modelos animais (Sus scrofa domestica), depostos em diferentes ambientes: dois modelos animais foram inumados (um dentro de um edifício e outro fora), e dois foram colocados à superfície (um dentro de um edifício e outro fora). A carcaça exposta às adversidades ambientais atingiu o estádio da esqueletização aos 147 dias enquanto a carcaça deposta à superfície mas protegida por uma estrutura, atingiu o mesmo estádio ao fim de 10 dias após a morte, pelo que podemos afirmar que a existência de uma proteção contra as flutuações de temperatura e das restantes alterações climáticas favoreceu o processo, acelerando-o. Em relação às carcaças inumadas, estas apresentavam quantidades desiguais de tecidos moles, sendo que a carcaça que também se encontrava protegida pelo edifício se encontrava com bastantes mais tecidos e menos decompostos. Os métodos de Megyesi e colegas (2005) e Vass (2011) demonstraram uma reduzida aplicabilidade. Relativamente às metodologias de Galloway e colegas (1989) podemos afirmar que no caso das carcaças expostas os estádios atribuídos nem sempre se encontram dentro dos limites sugeridos. Quando nos referimos aos estádios de Behrensmeyer (1978) observámos que funcionam relativamente bem para a nossa região geográfica. Com base nestes resultados, podemos assim afirmar que estimar o PMI é de fato uma tarefa bastante complexa e que deve ser conjugada com todas as particularidades existentes na cena envolvente.Different deposition environments, such as burial or surface deposition, will influence the decomposition of a body due to their specific characteristics. These environmental conditions can change the process, accelerating it or even preventing its continuation. In general, the burial of a corpse protects it from several destructive taphonomic agents. Estimation of postmortem interval (PMI) is critical to reconstruct the events surrounding the death of an individual. Despite representing a pertinent question in legal issues, the estimation of PMI is of particular difficulty. This is confirmed by the lack of reliable methods that currently exist to estimate it, particularly when it comes to the post skeletonization period. This study aims to contribute to a better understanding of the decomposition process in Mediterranean weather as well as several extrinsic factors that affect the body’s decay, such as the site of deposition. For this purpose, we used four animal models (Sus scrofa domestica) deposed in different environments: two animal models were buried (one within and one outside a building) and two were positioned on the surface (one inside of a building and another one outside). The carcass exposed to environmental adversities skeletonized within 147 days while the carcass deposed on the surface, but protected by a structure, reached the same stage 10 days after death, leading us to assume that the existence of a protection against temperature fluctuations and other climatic changes promoted the decomposition process, accelerating it. Regarding the buried carcasses, these had unequal amounts of soft tissue; the carcass protected by a house like structure was less decomposed and presented more soft tissues. The methods of Megyesi et al. (2005) and Vass (2011) demonstrated a reduced applicability. Regarding Galloway and colleagues (1989) stages of decay, this study leads us to conclude that for the animal models exposed to weather adversities the assigned stages where not always in accordance with the suggested time limits. When applying Behrensmeyer (1978) stages we observed that it works relatively well for our geographic region. On the basis of the results we can affirm that the estimation of PMI is in fact a very complex task; its estimation must have in account all particularities of the surrounding scene