Metilação e CCR

Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas MonizO Cancro Cólon Retal (CCR) é um dos cancros mais comuns no mundo, sendo o terceiro mais frequente e mortal a nível mundial, com uma incidência de cerca de 9% e provocando a morte de aproximadamente 394000 pessoas/ano. O desenvolvimento desta neoplasia surge maioritariamente associado a uma sequência e acumulação de mutações genéticas, designada sequência adenoma-carcinoma. Esta doença pode também ser causada por outro mecanismo genético, a instabilidade de microssatélites (MSI). Esta associa-se à carcinogénese cólon retal pela presença de mutações em genes envolvidos nos mecanismos de reparação do DNA. Recentemente, uma nova via molecular, envolvendo principalmente mecanismos epigenéticos, foi descoberta como outra possível causa no desenvolvimento de CCR. Nesta via, alterações epigenéticas como a metilação do DNA, modificações das histonas, alterações da estrutura da cromatina, perda de imprinting genómico e microRNAs foram associadas à carcinogénese cólon retal. Este trabalho teve como objetivo o estudo das alterações epigenéticas na carcinogénese do CCR, em particular, a influência da metilação do DNA no desenvolvimento desta patologia. Para este estudo, foi realizada uma pesquisa bibliográfica no motor de busca Pubmed utilizando os termos ―Cancer‖, ―Colorectal‖, ―Methylation‖ e ―Epigenetic‖. A metilação do DNA é fundamental na modulação da expressão genética, e nas células cancerígenas, a alteração do padrão de metilação do DNA inclui a hipermetilação das ilhas CpG e a hipometilação global do DNA. Esta deteção aberrante da metilação tem sido usada clinicamente para estratificar o risco de desenvolver cancro e na deteção precoce e prognóstico do cancro. Uma vez que a alteração da metilação do DNA é reversível, esta tem sido recentemente estudada como um possível alvo na terapêutica anticancerígena ou em terapêuticas de combinação, no tratamento do CCR. Para além disto, vários estudos apontam que a metilação do DNA pode ser utilizada como um biomarcador no diagnóstico, avaliação e prognóstico desta neoplasia

A review of publications in hair testing: 2020-2023

Comunicação apresentada no 27th Meeting of the Society of Hair Testing.Introduction and Aims: Since its first use until now, the relevance of hair in the toxicological expertise has evolved, mainly due to its advantages over traditional samples. Despite the fact that it is one of the most used alternative specimens, hair still presents important challenges. The objective of this study was to perform a bibliographic review of scientific publications on toxicological applications of hair testing between the years 2020 and 2023. Materials & Methods: The Scopus database was used for literature search, for papers published from 2020 to 2023 (10th April), and only articles written in English were considered. The search strings for terms included in the title, abstract or keywords were “hair testing” and “hair samples”. The papers were independently reviewed by four of the authors to determine their relevance in the context of this study. Results & Discussion: Taking into consideration these criteria and search strings, 218 articles were found, from which 18 were excluded since animal hair specimens had been used. The papers were classified according to type (e.g. review, research paper), analytes, extraction and clean-up approaches. Each paper could be placed under more than one category, except review papers (32 articles). Concerning analytes, the highest number of papers involved drugs of abuse (175, from which 45 involving new psychoactive substances), drugs (44) and alcohol biomarkers (17). Other biomarkers included hormones, endocannabinoids, etc. (44 papers, 25 of which involved cortisol). Most studies involve protein precipitation and direct injection (91), and only 12 studies address the issues of cosmetic treatments or drug adulterants. Conclusions: Hair testing is still mainly directed to the determination of drugs of abuse, and new psychoactive substances are still seldom included. Additionally, other applications are becoming more relevant, for instance the use of hair to determine biomarkers in some diseases.N/

Sensors in the Detection of Abused Substances in Forensic Contexts: A Comprehensive Review

orensic toxicology plays a pivotal role in elucidating the presence of drugs of abuse in both biological and solid samples, thereby aiding criminal investigations and public health initiatives. This review article explores the significance of sensor technologies in this field, focusing on diverse applications and their impact on the determination of drug abuse markers. This manuscript intends to review the transformative role of portable sensor technologies in detecting drugs of abuse in various samples. They offer precise, efficient, and real-time detection capabilities in both biological samples and solid substances. These sensors have become indispensable tools, with particular applications in various scenarios, including traffic stops, crime scenes, and workplace drug testing. The integration of portable sensor technologies in forensic toxicology is a remarkable advancement in the field. It has not only improved the speed and accuracy of drug abuse detection but has also extended the reach of forensic toxicology, making it more accessible and versatile. These advancements continue to shape forensic toxicology, ensuring swift, precise, and reliable results in criminal investigations and public health endeavours.info:eu-repo/semantics/publishedVersio

Microextraction action by packed sorbent in forensic drug analysis

Comunicação apresentada no 13º Encontro Nacional de Cromatografia, Lisboa, 17-19 dezembro, 2023.Microextraction by packed sorbent (MEPS) efficiently combines extraction, pre-concentration, and cleanup in a single device comprising two parts: the MEPS syringe and the packed sorbent bed1. MEPS has been used for several bioanalytical applications, including extraction of endogenous metabolites, biomarkers, and drugs from biological samples. It is particularly useful in metabolomics and pharmacokinetic studies2,3. Regarding MEPS applicability to forensic toxicology, urine is the most used specimen, followed by oral fluid (despite of its relatively high viscosity). Protein precipitation followed by centrifugation and with, or without dilution of the supernatant is the most commonly reported approach. The most detected compounds in forensic settings using MEPS are drugs of abuse [opiates and opioids (26%), cocaine (13%) cathinones (11%), dissociative hallucinogens (11%), cannabinoids and amphetamines (9% each) and other drugs (10%)] and medicinal drugs [antidepressants (9%), benzodiazepines/Z drugs (4%)]. MEPS was also applied to a beverage for forensic purposes e.g. to evaluate its composition in drug-facilitated crimes. An important feature in MEPS is the miniaturization of the sorbent. A careful selection of the sorbent will allow working with complex matrices, separating the target analytes from interferences and improve recoveries. The most widely selected sorbent was the silica based C18 that is a popular reversed-phase material (41%). Starting in the 2000s, new modifications of sorbents appeared. Overall, what the future holds for MEPS applications in forensic toxicology is promising, and ongoing research and technological advancements are likely to enhance the capabilities of MEPS approaches, making this technique an increasingly valuable tool for toxicological investigations.N/

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved