Publications by authors named "A F Peixoto"

567 Publications

Purification, Characterization, and Assessment of Antimicrobial Activity and Toxicity of Portulaca elatior Leaf Lectin (PeLL).

Probiotics Antimicrob Proteins 2021 Aug 21. Epub 2021 Aug 21.

Departamento de Bioquímica, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.

Lectins are carbohydrate-binding proteins with several bioactivities, including antimicrobial properties. Portulaca elatior is a species found at Brazilian Caatinga and data on the biochemical composition of this plant are scarce. The present work describes the purification of P. elatior leaf lectin (PeLL) as well as the assessment of its antimicrobial activity and toxicity. PeLL, isolated by chromatography on a chitin column, had native liquid charge and subunit composition evaluated by electrophoresis. Hemagglutinating activity (HA) of PeLL was determined in the presence of carbohydrates or divalent cations, as well as after heating and incubation at different pH values. Changes in the lectin conformation were monitored by evaluating intrinsic tryptophan fluorescence and using the extrinsic probe bis-ANS. Antimicrobial activity was evaluated against Pectobacterium strains and Candida species. The minimal inhibitory (MIC), bactericidal (MBC), and fungicidal (MFC) concentrations were determined. Finally, PeLL was evaluated for in vitro hemolytic activity in human erythrocytes and in vivo acute toxicity in mice (5 and 10 mg/kg b.w. per os). PeLL (pI 5.4; 20 kDa) had its HA was inhibited by mannose, galactose, Ca, Mg, and Mn. PeLL HA was resistant to heating at 100 °C, although conformational changes were detected. PeLL was more active in the acidic pH range, in which no conformational changes were observed. The lectin presented MIC and MBC of 0.185 and 0.74 μg/mL for all Pectobacterium strains, respectively; MIC of 1.48 μg/mL for C. albicans, C. tropicalis, and C. krusei; MIC and MFC of 0.74 and 2.96 μg/mL for C. parapsilosis. No hemolytic activity or signs of acute toxicity were observed in the mice. In conclusion, a new, low-toxic, and thermostable lectin was isolated from P. elatior leaves, being the first plant compound to show antibacterial activity against Pectobacterium.
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http://dx.doi.org/10.1007/s12602-021-09837-wDOI Listing
August 2021

Glucose-Lowering Drugs to Reduce Cardiovascular Risk in Type 2 Diabetes.

N Engl J Med 2021 Aug;385(7):669-670

Yale School of Medicine, New Haven, CT

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http://dx.doi.org/10.1056/NEJMc2107340DOI Listing
August 2021

The ACE (Albumin, CRP, and Endoscopy) Index in Acute Colitis: Simplify to a Better Prognostic Prediction.

Inflamm Bowel Dis 2021 Jul 31. Epub 2021 Jul 31.

Gastroenterology Department, Centro Hospitalar Universitário de São João, Porto, Portugal.

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http://dx.doi.org/10.1093/ibd/izab189DOI Listing
July 2021

Quality by design (QbD) optimization of diazepam-loaded nanostructured lipid carriers (NLC) for nose-to-brain delivery: Toxicological effect of surface charge on human neuronal cells.

Int J Pharm 2021 Jul 27;607:120933. Epub 2021 Jul 27.

UCIBIO/REQUIMTE, MEDTECH, Laboratory of Pharmaceutical Technology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; FP-ENAS (UFP Energy, Environment and Health Research Unit), CEBIMED (Biomedical Research Centre), Faculty of Health Sciences, University Fernando Pessoa, 4249-004 Porto, Portugal. Electronic address:

Diazepam is commonly used in the management of epileptic seizures, although it has limitations that can be overcome by using formulations that are easier to administer and capable of directing the drug to the brain. In this field, it has been reported that the use of nanostructured lipid carriers (NLC) via intranasal (or via nose-to-brain) promotes the targeting of drugs to the brain, improving the effectiveness of therapy. The aim of this work was to optimize two diazepam-loaded NLC formulations for nose-to-brain delivery, one with positive surface charge and one with negative surface charge. The quality by design (QbD) approach was used to design the experiments, where the quality target product profile (QTPP), the risk assessment and the critical quality attributes (CQAs) were defined to ensure safety, efficacy and quality of the final formulations. The experiments started with the optimization of critical material attributes (CMAs), related to the ratios of lipids and emulsifiers, followed by the selection of critical process parameters (CPPs), related to the production methods of the diazepam-loaded NLC formulation (ultrasound technique and high-pressure homogenization - HPH). Afterwards, the positive surface charge of the diazepam-loaded NLC was optimized. Finally, the biocompatibility with human neuronal cells of the formulation with a negative surface charge and of the formulation with a positive surface charge was evaluated. The results of the optimization of the CMAs showed that the ratios of lipids and emulsifiers more adequate were 6.7:2.9 and 4.2:0.3 (% w,w), respectively. Regarding the CPPs, HPH was considered the most suitable production method, resulting in an optimized diazepam-loaded NLC formulation (F1C15) with negative surface charge, showing particle size of 69.59 ± 0.22 nm, polydispersity index (PDI) of 0.19 ± 0.00, zeta potential (ZP) of -23.50 ± 0.24 mV and encapsulation efficiency (EE) of 96.60 ± 0.03 %. The optimized diazepam-loaded NLC formulation (F2A8) with positive surface charge had particle size of 124.40 ± 0.84 nm, PDI of 0.17 ± 0.01, ZP of 32.60 ± 1.13 mV and EE of 95.76 ± 0.24 %. In addition, the incorporation of diazepam in NLC resulted in a sustained release of the drug. No significant changes in particle size, PDI, ZP and EE were observed for the formulation F1C15, after 3 months of storage, whereas for formulation F2A8, particle size increased significantly. Biocompatibility studies showed that the formulation F2A8 was more cytotoxic than the formulation F1C15. Thereby, we conclude that the formulation F1C15 is more suitable for targeting the brain, when compared with the formulation F2A8. From the results of these studies, it can be confirmed that the QbD approach is an adequate and central tool to optimize NLC formulations.
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http://dx.doi.org/10.1016/j.ijpharm.2021.120933DOI Listing
July 2021

Gastroduodenal ischemia in a patient with severe SARS-CoV-2 infection.

Rev Esp Enferm Dig 2021 Jul 28. Epub 2021 Jul 28.

Gastroenterology, Centro Hospitalar Universitário de São João.

A 54-year-old male, with a past medical history of hypertension, dyslipidemia, obesity and diastolic heart failure, was admitted due to COVID-19 pneumonia. Respiratory failure gradually deteriorated and the patient was transferred to the Intensive Care Unit (ICU), where mechanical ventilation and venovenous extracorporeal membrane oxygenation (VV-ECMO) were started. On the second day in ICU, he had a septic shock due to ventilator-associated pneumonia. Five days later, the patient had new-onset melena and laboratory data showed a hemoglobin level of 7.8g/dL.
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http://dx.doi.org/10.17235/reed.2021.8178/2021DOI Listing
July 2021
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