Glutaraldehyde-crosslinking chitosan scaffolds reinforced with calcium phosphate spray-dried granules for bone tissue applications

The clinical demand for bone scaffolds as an alternative strategy for bone grafting has increased exponentially and, up to date, numerous formulations have been proposed to regenerate the bone tissue. However, most of these structures lack at least one of the fundamental/ideal properties of these materials (e.g., mechanical resistance, interconnected porosity, bioactivity, biodegradability, etc.). In this work, we developed innovative composite scaffolds, based on crosslinked chitosan with glutaraldehyde (GA), combined with different atomized calcium phosphates (CaP) granules - hydroxyapatite (HA) or biphasic mixtures of HA and β - tricalcium phosphate (β-TCP), with improved biomechanical behavior and enhanced biological response. This innovative combination was designed to improve the scaffolds' functionality, in which GA improved chitosan mechanical strength and stability, whereas CaP granules enhanced the scaffolds' bioactivity and osteoblastic response, further reinforcing the scaffolds' structure. The biological assessment of the composite scaffolds showed that the specimens with 0.2% crosslinking were the ones with the best biological performance. In addition, the inclusion of biphasic granules induced a trend for increase osteogenic activation, as compared to the addition of HA granules. In conclusion, scaffolds produced in the present work, both with HA granules or the biphasic ones, and with low concentrations of GA, have shown adequate properties and enhanced biological performance, being potential candidates for application in bone tissue engineering.publishe

Spray Drying: An Overview

Spray drying is a well-known method of particle production which comprises the transformation of a fluid material into dried particles, taking advantage of a gaseous hot drying medium, with clear advantages for the fabrication of medical devices. In fact, it is quite common the production of microspheres and microcapsules designed for drug delivery systems. This review describes the different stages of the mechanism of the spray-drying process: atomization, droplet-to-particle conversion and particle collection. In particular, this work addresses the diversity of available atomizers, the drying kinetics and the importance of the configuration of the drying chamber, and the efficiency of the collection devices. The final properties of the dried products are influenced by a variety of factors, namely the spray dryer design, the feed characteristics and the processing parameters. The impact of those variables in optimizing both the spray-drying process and the synthesis of dried particles with desirable characteristics is discussed. The scalability of this manufacturing process in obtaining dried particles in submicron-to-micron scale favors a variety of applications within the food, chemical, polymeric, pharmaceutical, biotechnology and medical industries

Effects of a 10 km race on physiological and immunological responses

Introduction: The number of 10 km running races has been increasing in Brazil and the number of finishers almost triplicated in the last decade. However, there is limited amount of data showing the relationship between this event and the immune system response. Aim: Investigate the effects of a 10 km running race on physiological and immunological response in healthy well trained male volunteers. Methods: Fourteen male participants (32,21 ± 10,24 years old, 78,80 ± 9,30 kg) took part in this study. Ratings of perceived exertion (RPE), visual analog scale (VAS), heart rate (HR) and blood samples were taken before, immediately and 24 hours after the race. Lactate, glucose, creatine kinase (CK) and C-reactive protein (CRP), as well as leukocyte number and subpopulation of T cell (CD4+ and CD8+) were analyzed. Results: Participants completed this race in 49,85 ± 7,04 min. There was a significant increase post-race compared to pre-race for HR (67 ± 9 to 159 ± 21 bpm), RPE (6 ± 0 to 15 ± 2) and lactate (3.6 to 6.6 mmol/dL). Glucose levels did not present any significant changes. CK level did not change immediately after the race, but was higher (131,21 ± 62,50 to 286,85 ± 234,35 U/L ) at the 24 h post-race time point. CRP was lower at 24 h (8,37 ± 2,23 to 4,50 ± 2,28 mg/dL). VAS values changed from 0 (before) to 5,64 ± 2,20 (immediately after) to 2,21 ± 2,86 (24 hours). The number of circulating leukocyte (5,83 ± 0,89 to 9,15 ± 1,77 103/µL), neutrophil (2,96 ± 0,49 to 4,34 ± 0,73 103/µL), lymphocyte (2,21 ± 0,57 to 3,92 ± 1,27 103/µL), monocyte (0,46 ± 0,10 to 0,64 ± 0,23 103/µL) and basophil (0,05 ± 0,02 to 0,09 ± 0,03 103/µL) increased significantly immediately after the race, returning to the basal level in 24 h. There was no difference in circulating eosinophils number. The absolute number of CD4+ (828,5 ± 215,8 to 1063,2 ± 235,3 cell/µL) and CD8+ (766,92 ± 347,79 to 1470,30 ± 782,90 cell/µL) also increased immediately after the race returning to basal in 24 h. Significant reduction of the CD4+/CD8+ lymphocyte subpopulation ratio (1,21 ± 0,45 to 0,85 ± 0,33 cell/µL) was observed post-race returning to basal level at 24 h post-race. Results are presented as mean ± SD. (p\u3c0,0001). Conclusion: These results suggest that a 10 km running race is an intense physical activity and induces physiological changes. In addition, intense running provokes a significantly, although transient, modulation of the immune system, specifically of leukocyte sub-population

Evidence that the insertion events of IS2 transposition are biased towards abrupt compositional shifts in target DNA and modulated by a diverse set of culture parameters

Insertion specificity of mobile genetic elements is a rather complex aspect of DNA transposition, which, despite much progress towards its elucidation, still remains incompletely understood. We report here the results of a meta-analysis of IS2 target sites from genomic, phage, and plasmid DNA and find that newly acquired IS2 elements are consistently inserted around abrupt DNA compositional shifts, particularly in the form of switch sites of GC skew. The results presented in this study not only corroborate our previous observations that both the insertion sequence (IS) minicircle junction and target region adopt intrinsically bent conformations in IS2, but most interestingly, extend this requirement to other families of IS elements. Using this information, we were able to pinpoint regions with high propensity for transposition and to predict and detect, de novo, a novel IS2 insertion event in the 3′ region of the gfp gene of a reporter plasmid. We also found that during amplification of this plasmid, process parameters such as scale, culture growth phase, and medium composition exacerbate IS2 transposition, leading to contamination levels with potentially detrimental clinical effects. Overall, our findings provide new insights into the role of target DNA structure in the mechanism of transposition of IS elements and extend our understanding of how culture conditions are a relevant factor in the induction of genetic instability.Fundação para a Ciência e a Tecnologia (PTDC/EBB-EBI/113650/2009)MIT-Portugal Progra

Corantes nos Alimentos e o Ensino de Química

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Methodology for phytoplankton taxonomic group identification towards the development of a lab-on-a-chip

This paper presents the absorbance and fluorescence optical properties of various phytoplankton species, looking to achieve an accurate method to detect and identify a number of phytoplankton taxonomic groups. The methodology to select the excitation and detection wavelengths that results in superior identification of phytoplankton is reported. The macroscopic analyses and the implemented methodology are the base for designing a lab-on-a-chip device for a phytoplankton group identification, based on cell analysis with multi-wavelength lighting excitation, aiming for a cheap and portable platform. With such methodology in a lab-on-a-chip device, the analysis of the phytoplankton cells’ optical properties, e.g., fluorescence, diffraction, absorption and reflection, will be possible. This device will offer, in the future, a platform for continuous, autonomous and in situ underwater measurements, in opposition to the conventional methodology. A proof-of-concept device with LED light excitation at 450 nm and a detection photodiode at 680 nm was fabricated. This device was able to quantify the concentration of the phytoplankton chlorophyll a. A lock-in amplifier electronic circuit was developed and integrated in a portable and low-cost sensor, featuring continuous, autonomous and in situ underwater measurements. This device has a detection limit of 0.01 µ/L of chlorophyll a, in a range up to 300 µg/L, with a linear voltage output with chlorophyll concentration.European Regional Development Fund (ERDF) through the Interreg VA Spain-Portugal (POCTEP) 2014–2020 Program under grant agreement 0591_FOODSENS_1_E, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020, and by project NORTE-08-5369-FSE-000039 co-founded by the European Social Fund FSE and through National funds NORTE 2020 and Regional Operacional Programa of North 2014/2020. The University of Vigo work was funded by a Xunta de Galicia grant to the Biological Oceanography Research Group (Consolidación e estruturación de unidades). This output reflects only the views of the authors, and the program authorities cannot be held responsible for any use that may be made of the information contained therei

Methodology for phytoplankton taxonomic group identification towards the development of a lab-on-a-chip

This paper presents the absorbance and fluorescence optical properties of various phytoplankton species, looking to achieve an accurate method to detect and identify a number of phytoplankton taxonomic groups. The methodology to select the excitation and detection wavelengths that results in superior identification of phytoplankton is reported. The macroscopic analyses and the implemented methodology are the base for designing a lab-on-a-chip device for a phytoplankton group identification, based on cell analysis with multi-wavelength lighting excitation, aiming for a cheap and portable platform. With such methodology in a lab-on-a-chip device, the analysis of the phytoplankton cells’ optical properties, e.g., fluorescence, diffraction, absorption and reflection, will be possible. This device will offer, in the future, a platform for continuous, autonomous and in situ underwater measurements, in opposition to the conventional methodology. A proof-of-concept device with LED light excitation at 450 nm and a detection photodiode at 680 nm was fabricated. This device was able to quantify the concentration of the phytoplankton chlorophyll a. A lock-in amplifier electronic circuit was developed and integrated in a portable and low-cost sensor, featuring continuous, autonomous and in situ underwater measurements. This device has a detection limit of 0.01 µ/L of chlorophyll a, in a range up to 300 µg/L, with a linear voltage output with chlorophyll concentration.Fundação para a Ciência e a Tecnologia | Ref. UIDB/04436/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/04436/2020Fundação para a Ciência e a Tecnologia | Ref. PD/BD/150581/2020Fundação para a Ciência e a Tecnologia | Ref. 2021.01087.CEECINDFundação para a Ciência e a Tecnologia | Ref. 2021.01086.CEECIN

2,3-Diarylxanthones as potential inhibitors of Arachidonic acid metabolic pathways

In response to an inflammatory stimulus, arachidonic acid (AA), the main polyunsaturated fatty acid present in the phospholipid layer of cell membranes, is released and metabolized to a series of eicosanoids. These bioactive lipid mediators of inflammation arise physiologically through the action of the enzymes 5-lipoxygenase (5-LOX) and cyclooxygenases (constitutive COX-1 and inducible COX-2). It is believed that dual inhibition of 5-LOX and COXs may have a higher beneficial impact in the treatment of inflammatory disorders rather than the inhibition of each enzyme. With this demand for new dual-acting anti-inflammatory agents, a range of 2,3-diarylxanthones were tested through their ability to interact in the AA metabolism. In vitro anti-inflammatory activity was evaluated through the inhibition of 5-LOX-catalyzed leukotriene B4 (LTB4) formation in human neutrophils and inhibition of COX-1- and COX-2-catalyzed prostaglandin E2 (PGE2) formation in human whole blood. The results showed that some of the studied arylxanthones were able to prevent LTB4 production in human neutrophils, in a concentration-dependent manner. The xanthone with a 2-catechol was the most active one (IC50 ∼ 9 μM). The more effective arylxanthones in preventing COX-1-catalyzed PGE2 production presented IC50 values from 1 to 7 μM, exhibiting a structural feature with at least one non-substituted aryl group. All the studied arylxanthones were ineffective to prevent the formation of PGE2 catalyzed by COX-2, up to the maximum concentration of 100 μM. The ability of the tested 2,3-diarylxanthones to interact with both 5-LOX and COX-1 pathways constitutes an important step in the research of novel dual-acting anti-inflammatory drugs.Sincere thanks are expressed to Faculdade de Farmácia da Universidade do Porto, Universidade de Aveiro, Instituto Politécnico de Bragança, Fundação para a Ciência e a Tecnologia (FCT, Portugal), Ministério da Educação e Ciência, European Union, FEDER, PT 2020, QREN, and COMPETE funding UCIBIO, REQUIMTE [(PT2020 UID/MULTI/04378/2013 - POCI/01/0145/FEDER/007728), (NORTE-01-0145-FEDER-000024), and (PTDC/QEQ-QAN/1742/2014 – POCI-01-0145- FEDER-016530)] and QOPNA (FCT UID/QUI/00062/2013) Research Units and also to the Portuguese National NMR Network (RNRMN). We gratefully acknowledge Graça Porto and the nursing staff of the Centro Hospitalar do Porto - Hospital de Santo António blood bank for the collaboration in the recruitment of blood donors involved in the present work.info:eu-repo/semantics/publishedVersio