Leucine-rich diet supplementation modulates foetal muscle protein metabolism impaired by Walker-256 tumour

Cancer-cachexia induces a variety of metabolic disorders of protein turnover and is more pronounced when associated with pregnancy. Tumour-bearing pregnant rats have impaired protein balance, which decreases protein synthesis and increases muscle breakdown. Because branched-chain amino acids, especially leucine, stimulate protein synthesis, we investigated the effect of a leucine-rich diet on protein metabolism in the foetal gastrocnemius muscles of tumour-bearing pregnant rats. Foetuses of pregnant rats with or without Walker 256 tumours were divided into six groups. During the 20 days of the experiment, the pregnant groups were fed with either a control diet (C, control rats; W, tumour-bearing rats; Cp, rats pair-fed the same normoprotein-diet as the W group) or with a leucine-rich diet (L, leucine rats; LW, leucine tumour-bearing rats; and Lp, rats pair-fed the same leucine-rich diet as the LW group). After the mothers were sacrificed, the foetal gastrocnemius muscle samples were resected, and the protein synthesis and degradation and tissue chymotrypsin-like, cathepsin and calpain enzyme activities were assayed. The muscle oxidative enzymes (catalase, glutathione-S-transferase and superoxide dismutase), alkaline phosphatase enzyme activities and lipid peroxidation (malondialdehyde) were also measured. Tumour growth led to a reduction in foetal weight associated with decreased serum protein, albumin and glucose levels and low haematocrit in the foetuses of the W group, whereas in the LW foetuses, these changes were less pronounced. Muscle protein synthesis (measured by L-[3H]-phenylalanine incorporation) was reduced in the W foetuses but was restored in the LW group. Protein breakdown (as assessed by tyrosine release) was enhanced in the L and W groups, but chymotrypsin-like activity increased only in group W and tended toward an increase in the LW foetuses. The activity of cathepsin H was significantly higher in the W group foetuses, but the proteolytic calcium-dependent pathway showed similar enzyme activity. In parallel, an intense oxidative stress process was observed only in the group W foetuses. These data suggested that the proteasomal and lysosomal proteolytic pathways and oxidative stress are likely to participate in the process of foetal muscle catabolism of Walker's tumour-bearing pregnant rats. The present work shows that foetal muscle can be protected by supplementation with a leucine-rich diet

Nitric oxide release from antimicrobial peptide hydrogels for wound healing

Nitric oxide (NO) is an endogenously produced molecule that has been implicated in several wound healing mechanisms. Its topical delivery may improve healing in acute or chronic wounds. In this study an antimicrobial peptide was synthesized which self-assembled upon a pH shift, forming a hydrogel. The peptide was chemically functionalized to incorporate a NO-donor moiety on lysine residues. The extent of the reaction was measured by ninhydrin assay and the NO release rate was quantified via the Griess reaction method. The resulting compound was evaluated for its antimicrobial activity against Escherichia coli, and its effect on collagen production by fibroblasts was assessed. Time-kill curves point to an initial increase in bactericidal activity of the functionalized peptide, and collagen production by human dermal fibroblasts when incubated with the NO-functionalized peptide showed a dose-dependent increase in the presence of the NO donor within a range of 0–20 µM.This work was financed by FEDER (Fundo Europeu de Desenvolvimento Regional) funds via COMPETE 2020 (Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020), and by Portuguese funds through FCT (Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia e Ensino Superior) in the framework of the projects “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274) and PTDC/QUI-QFI/29914/2017, as well through the grant SFRH/BD/84914/2012. Thanks to FCT also for supporting Research Unit LAQV-REQUIMTE through the project UID/QUI/5006/2013

Nano-hydroxyapatite in oral care cosmetics: characterization and cytotoxicity assessment

Nano-hydroxyapatite has been used as an oral care ingredient, being incorporated in several products for the treatment of dental hypersensitivity and enamel remineralisation. Despite its promising results, regulatory and safety concerns have been discussed and questioned by the European Scientific Committee on Consumer Safety (SCCS) regarding the usage of hydroxyapatite nanoparticles in oral care products. In this work, a commercially available nano-hydroxyapatite was characterized and its cytocompatibility towards human gingival fibroblasts was evaluated, as well as its irritation potential using the in vitro HET-CAM assay. All the conditions chosen in this study tried to simulate the tooth brushing procedure and the hydroxyapatite nanoparticles levels normally incorporated in oral care products. The commercial hydroxyapatite nanoparticles used in this study exhibited a rod-like morphology and the expected chemical and phase composition. The set of in vitro cytotoxicity parameters accessed showed that these nanoparticles are highly cytocompatible towards human gingival fibroblasts. Additionally, these nanoparticles did not possess any irritation potential on HET-CAM assay. This study clarifies the issues raised by SCCS and it concludes that this specific nano-hydroxyapatite is cytocompatible, as these nanoparticles did not alter the normal behaviour of the cells. Therefore, they are safe to be used in oral care products.The authors acknowledge the support of the Biointerfaces and Nanotechnology i3S Scientific Platform, as well as Luís Teixeira and Marta Ferro from University of Aveiro for the characterization of the HA-NP with TEM. Financial support from the European Union (FEDER funds POCI/01/0145/FEDER/007265) and National Funds (FCT/MEC, Fundação para a Ciência e Tecnologia and Ministério da Educação e Ciência) under the Partnership Agreement PT2020 UID/QUI/50006/2019 is acknowledged

Lack of the transcription factor hypoxia-inducible factor (HIF)-1α in macrophages accelerates the necrosis of Mycobacterium avium-induced granulomas

Accepted ManuscriptThe establishment of mycobacterial infection is characterized by the formation of granulomas, which are well-organized aggregates of immune cells, namely, infected macrophages. The granuloma's main function is to constrain and prevent dissemination of the mycobacteria while focusing the immune response to a limited area. In some cases these lesions can grow progressively into large granulomas which can undergo central necrosis, thereby leading to their caseation. Macrophages are the most abundant cells present in the granuloma and are known to adapt under hypoxic conditions in order to avoid cell death. Our laboratory has developed a granuloma necrosis model that mimics the human pathology of Mycobacterium tuberculosis, using C57BL/6 mice infected intravenously with a low dose of a highly virulent strain of Mycobacterium avium. In this work, a mouse strain deleted of the hypoxia inducible factor 1a (HIF-1a) under the Cre-lox system regulated by the lysozyme M gene promoter was used to determine the relevance of HIF-1a in the caseation of granulomas. The genetic ablation of HIF-1a in the myeloid lineage causes the earlier emergence of granuloma necrosis and clearly induces an impairment of the resistance against M. avium infection coincident with the emergence of necrosis. The data provide evidence that granulomas become hypoxic before undergoing necrosis through the analysis of vascularization and quantification of HIF-1a in a necrotizing mouse model. Our results show that interfering with macrophage adaptation to hypoxia, such as through HIF-1a inactivation, accelerates granuloma necrosis.Support from national funds through FCT/MEC (Fundação para a Ciência e a Tecnologia/Ministério da Educação e Ciência), when applicable cofunded by FEDER funds within the partnership agreement PT2020 related to the research unit number 4293; from “NORTE-07-0124-FEDER-000002-Host-Pathogen Interactions,” cofunded by Programa Operacional Regional do Norte (ON.2–O Novo Norte), under the Quadro de Referência Estratégico Nacional (QREN); and from HMSP-ICT/0024/2010. T.M.S. received postdoctoral grant ON2201310 from “NORTE-07-0124-FEDER-000002-Host-Pathogen Interactions,” cofunded by Programa Operacional Regional do Norte (ON.2–O Novo Norte), under the Quadro de Referência Estratégico Nacional (QREN). M.R. received Ph.D. grant SFRH/BD/89871/2012 from FCT, Portuga

A force-balanced control volume finite element method for multi-phase porous media flow modelling

A novel method for simulating multi-phase flow in porous media is presented. The approach is based on a control volume finite element mixed formulation and new force-balanced finite element pairs. The novelty of the method lies in: (a) permitting both continuous and discontinuous description of pressure and saturation between elements; (b) the use of arbitrarily high-order polynomial representation for pressure and velocity and (c) the use of high-order flux-limited methods in space and to time avoid introducing non-physical oscillations while achieving high-order accuracy where and when possible. The model is initially validated for two-phase flow. Results are in good agreement with analytically obtained solutions and experimental results. The potential of this method is demonstrated by simulating flow in a realistic geometry composed of highly permeable meandering channels

Ultra-thin EBG backed Fractal geometry-based antenna for 24 GHz ISM band WBAN

A compact, ultra-thin, electromagnetic bandgap (EBG) backed antenna is presented for the 24 GHz ISM band for WBAN applications. The proposed antenna has Koch fractal geometry-based bow-tie slots, designed with an overall dimension of 0.91 lambda_0 x 0.84 lambda_0 x 0.01 lambda_0, backed by a 5 x 5 element 0.01 lambda_0 thick EBG structure; it is fabricated on a flexible Rogers 5880 substrate (thickness = 0.127 mm, dielectric constant Epsilon_r = 2.2, tan delta = 0.0009). In comparison to previously published K band prototype antennas, our presented fractal antenna has a more compact and ultra-thin form factor. The low profile, via-less EBG unit cell structure with dimensions of 0.254 lambda_0 x 0.254 lambda_0, possesses both Artificial Magnetic Conductor (AMC) and EBG characteristics. It is straightforward to fabricate at a millimeter-scale. The performance parameters of the design are investigated in terms of on-body reflection coefficient and free-space radiation patterns with and without structural bending. The EBG structure enhances the antenna’s front-lobe gain by 2.3 dB, decreases back-lobe radiation by 12.6 dB, and decreases the specific absorption rate (SAR (1 g)) from > 50.9 W/kg to < 6.14 W/kg, significantly reducing potential harm to the human body. Experimental investigations revealed high insensitivity of the proposed antenna to body proximity, and performance is preserved with structural deformation

The effects of weather and climate change on dengue

There is much uncertainty about the future impact of climate change on vector-borne diseases. Such uncertainty reflects the difficulties in modelling the complex interactions between disease, climatic and socioeconomic determinants. We used a comprehensive panel dataset from Mexico covering 23 years of province-specific dengue reports across nine climatic regions to estimate the impact of weather on dengue, accounting for the effects of non-climatic factors

Deciphering the contribution of biofilm to the pathogenesis of peritoneal dialysis infections: characterization and microbial behaviour on dialysis fluids

Infections are major complications in peritoneal dialysis (PD) with a multifactorial etiology that comprises patient, microbial and dialytic factors. This study aimed at investigating the contribution of microbial biofilms on PD catheters to recalcitrant infections and their interplay with PD related-factors. A prospective observational study was performed on 47 patients attending Centro Hospitalar of Porto and Vila Nova de Gaia/Espinho to whom the catheter was removed due to infectious (n = 16) and non-infectious causes (n = 31). Microbial density on the catheter was assessed by culture methods and the isolated microorganisms identified by matrix-assisted laser desorption/ionization time-of-flight intact cell mass spectrometry. The effect of conventional and three biocompatible PD solutions on 16 Coagulase Negative Staphylococci (CNS) and 10 Pseudomonas aeruginosa strains planktonic growth and biofilm formation was evaluated. Cultures were positive in 87.5% of the catheters removed due infectious and 90.3% removed due to non-infectious causes. However, microbial yields were higher on the cuffs of catheters removed due to infection vs. non-infection. Staphylococci (CNS and Staphylococcus aureus) and P. aeruginosa were the predominant species: 32% and 20% in the infection and 43.3% and 22.7% in the non-infection group, respectively. In general, PD solutions had a detrimental effect on planktonic CNS and P. aeruginosa strains growth. All strains formed biofilms in the presence of PD solutions. The solutions had a more detrimental effect on P. aeruginosa than CNS strains. No major differences were observed between conventional and biocompatible solutions, although in icodextrin solution biofilm biomass was lower than in bicarbonate/lactate solution. Overall, we show that microbial biofilm is universal in PD catheters with the subclinical menace of Staphylococci and P. aeruginosa. Cuffs colonization may significantly contribute to infection. PD solutions differentially impact microbial species. This knowledge is important for the development of infection diagnosis, treatment and preventive strategies.This work received support from a Sociedade Portuguesa de Nefrologia (http://www.spnefro.pt) research grant to AR and a Fundação para a Ciência e Tecnologia (http://www.fct.pt) post doc grant (SFRH/BPD/73663/2010) to MM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript