Browsing by Author "Sousa, C."
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- Molecular picture of cobalamin C/D defects before and after newborn screening eraPublication . Nogueira, C.; Marcão, A.; Rocha, H.; Sousa, C.; Fonseca, H.; Valongo, C.; Vilarinho, L.Objective: Birth prevalence of Cobalamin (Cbl) C or D defects in Portugal is an estimated 1:85,000, one of the highest worldwide. We compared the genotype/phenotype of patients identified with CblC or CblD before and after the implementation of expanded newborn screening. Methods: Twenty-five Portuguese CblC/D patients, 14 symptomatic and 11 identified through screening, were diagnosed using gas chromatography or tandem mass spectrometry. Molecular characterization was performed through the study of MMACHC and MMADHC genes. Results: The most common MMACHC mutation, c.271dupA, was present in 100% of MMACHC alleles of all CblC screened patients, in contrast with the 61% identified before expanded newborn screening. All studied cases (except one, who presented a CblD deficiency) presented a CblC defect. More CblC late-onset patients were diagnosed before the introduction of newborn screening than in the post newborn screening era, probably because some early onset patients died without a definitive diagnosis. Conclusion: The molecular data found in this cohort contribute to the improvement of screening and diagnosis of Cbl defects and would enable a confirmatory diagnosis of these patients, reducing the need for complex, costly, laborious, and time-consuming biochemical/enzymatic tests.
- Neuroprotective effect of steroidal alkaloids on glutamate-induced toxicity by preserving mitochondrial membrane potential and reducing oxidative stressPublication . Taveira, M.; Sousa, C.; Valentão, P.; Ferreres, F.; Teixeira, João Paulo; Andrade, P.B.Several evidences suggest that enhanced oxidative stress is involved in the pathogenesis and/or progression of several neurodegenerative diseases. The aim of this study was to investigate for the first time whether both extracts from tomato plant (Lycopersicon esculentum Mill.) leaves and their isolated steroidal alkaloids (tomatine and tomatidine) afford neuroprotective effect against glutamate-induced toxicity in SH-SY5Y neuroblastoma cells and to elucidate the mechanisms underlying this protection. Steroidal alkaloids from tomato are well known for their cholinesterases' inhibitory capacity and the results showed that both purified extracts and isolated compounds, at non-toxic concentrations for gastric (AGS), intestinal (Caco-2) and neuronal (SH-SY5Y) cells, have the capacity to preserve mitochondria membrane potential and to decrease reactive oxygen species levels of SH-SY5Y glutamate-insulted cells. Moreover, the use of specific antagonists of cholinergic receptors allowed observing that tomatine and tomatidine can interact with nicotinic receptors, specifically with the α7 type. No effect on muscarinic receptors was noticed. In addition to the selective cholinesterases' inhibition revealed by the compounds/extracts, these results provide novel and important insights into their neuroprotective mechanism. This work also demystifies the applicability of these compounds in therapeutics, by demonstrating that their toxicity was overestimated for long time.
- Rapid response Task Force: addressing the detection of Aedes albopictus in Lisbon, PortugalPublication . Grau-Pujol, B.; Moreira, A.; Vieira Martins, J; Costa Osório, H; Ribeiro, L.; Dinis, A.; Sousa, C.; Alves, M. João; Leite, P. Pinto; Vasconcelos, P.Issue: The invasive Aedes albopictus mosquitoes are spreading in southern Europe and pose a heightened risk of mosquito-borne diseases, like Dengue and Chikungunya. On September 2023, A. albopictus was first identified in Lisbon through community-based surveillance and a multidisciplinary national Task Force (TF) was convened. Description of the problem: The TF included experts in epidemiology, entomology, environmental health, laboratory diagnosis, prevention and control and communication. The objectives were to i) confirm A.albopictus presence in Lisbon and adjust the risk assessment, ii) raise awareness and prevent mosquitoes’ spread, iii) revise national guidelines on arboviruses surveillance and control. During September-December 2023, the National Network for Vectors Surveillance (REVIVE) and the Hygiene and Tropical Medicine Institute sampled mosquito-prone habitats within 2km-radius of the detection point using QGIS software. They used snowball sampling to identify any new foci. They placed ovitraps for ongoing surveillance and conducted morphological analysis and xenomonitoring for pathogen DNA and RNA detection at the national reference laboratory. Results: By November 2023, A.albopictus was detected in two new foci. No mosquitoes tested positive for arboviruses, and no autochthonous cases of mosquito-borne diseases were identified. The TF developed national guidelines for vector prevention and control and awareness for arboviruses and trained municipality workers. To raise awareness, we communicated with experts and the public through existing channels and media. As of April 2024, no new foci have been detected. Lessons: Community-based surveillance and REVIVE approach were crucial for invasive A.albopictus detection and monitoring in Lisbon. Rapid multidisciplinary TF coordination may have been key for timely vector control.