Browsing by Author "Dias, Miguel Luís Sousa"
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- Chemical and biological studies of Portuguese Bee venomPublication . Dias, Miguel Luís Sousa; Estevinho, Leticia M.This research aimed to develop analytical methodologies for the quality control of apitoxin, as well as evaluating its biological activities. A spectrophotometer method was established to estimate the total protein content, equivalent to albumin, in the apitoxin samples. Its advantage lies in preserving sample integrity. Additionally, electrochemical methodologies were developed, allowing confirmation that apitoxin lacks antioxidant activity and implementing quality control measures for four heavy metals (Zn, Cd, Pb, and Cu). The antimicrobial activity of the five apitoxin samples revealed bactericidal action against all tested strains of Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae, except for Pseudomonas aeruginosa strains, which remained unaffected. Among the samples, Sample 1 exhibited the lowest MIC values (9.2 µg/mL) against Staphylococcus aureus, meaning that this bacteria was the most sensitive to the negative effects of apitoxine. The highest MIC (41.8 µg/mL) was observed against a strain of Klebsiella pneumoniae in the presence of Sample 5, denoting increased resistance to apitoxin. Portuguese apitoxin demonstrated significant inhibitory effects against various enzymes: xanthine oxidase (IC50 values ranged between 1.7± 0.4 and 6.3± 0.85 μg/mL), lipase (IC50 values ranged from 0.05 ± 0.01µg/mL to 0.16 ±0, 0.03 μg/mL), α-amylase (IC50 values between 0.08 ± 0.02 and 0.4 ± 0.12 μg/mL), α-glucosidase (IC50 values between 0.03 ± 0.01 and 0.14 ± 0.01 μg/mL), lipoxygenase (IC50 values in the range of 0.06± 0.01 to 0.25± 0.04 μg /mL), acetylcholinesterase (IC50 values ranged from 0.78 ± 0.2 to 3.75 ± 0.2 μg/mL), tyrosinase (IC50 values between 1.6 ± 0.1 to 4.8 ± 0.24 μg/mL), and hyaluronidase (inhibition percentage between 85±5.4 % and 75.0±3.3%). In conclusion, apitoxin possesses valuable antimicrobial and enzyme-inhibiting. These findings suggest that apitoxin could hold potential significance in addressing various health conditions and diseases, warranting further scientific investigations due to its potential application in clinical or pharmaceutical settings.
- Oxidative stress and inflammation in B-Cell lymphomasPublication . Sousa-Pimenta, Mário; Estevinho, Maria Manuela; Dias, Miguel Luís Sousa; Martins, Ângelo; Estevinho, Leticia M.Mature lymphoid neoplasms arise de novo or by the transformation of more indolent lymphomas in a process that relies on the stepwise accumulation of genomic and transcriptomic alterations. The microenvironment and neoplastic precursor cells are heavily influenced by pro-inflammatory signaling, regulated in part by oxidative stress and inflammation. Reactive oxygen species (ROSs) are by-products of cellular metabolism able to modulate cell signaling and fate. Moreover, they play a crucial role in the phagocyte system, which is responsible for antigen presentation and the selection of mature B and T cells under normal conditions. Imbalances in pro-oxidant and antioxidant signaling can lead to physiological dysfunction and disease development by disrupting metabolic processes and cell signaling. This narrative review aims to analyze the impact of reactive oxygen species on lymphomagenesis, specifically examining the regulation of microenvironmental players, as well as the response to therapy for B-cell-derived non-Hodgkin lymphomas. Further research is needed to investigate the involvement of ROS and inflammation in the development of lymphomas, which may unravel disease mechanisms and identify innovative therapeutic targets.