Understanding oral mucositis: a pilot study

info:eu-repo/semantics/acceptedVersio

Water activity in lamellar stacks of lipid bilayers: "Hydration forces" revisited

Water activity and its relationship with interactions stabilising lamellar stacks of mixed lipid bilayers in their fluid state are investigated by means of osmotic pressure measurements coupled with small-angle x-ray scattering. The (electrically-neutral) bilayers are composed of a mixture in various proportions of lecithin, a zwitterionic phospholipid, and Simulsol, a non-ionic cosurfactant with an ethoxylated polar head. For highly dehydrated samples the osmotic pressure profile always exhibits the "classical" exponential decay as hydration increases but, depending on Simulsol to lecithin ratio, it becomes either of the "bound" or "unbound" types for more water-swollen systems. A simple thermodynamic model is used for interpreting the results without resorting to the celebrated but elusive "hydration forces"Comment: 24 pages, 12 figures. Accepted for publication in The European Physical Journal

Differential right and left ventricular diastolic tolerance to acute afterload and NCX gene expression in Wistar rats

This study evaluated right ventricular (RV) and left ventricular (LV) diastolic tolerance to afterload and SERCA2a, phospholamban and sodium-calcium exchanger (NCX) gene expression in Wistar rats. Time constant tau and end-diastolic pressure-dimension relation (EDPDR) were analyzed in response to progressive RV or LV afterload elevations, induced by beat-to-beat pulmonary trunk or aortic root constrictions, respectively. Afterload elevations decreased LV-tau, but increased RV-tau. Whereas LV-tau analyzed the major course of pressure fall, RV-tau only assessed the last fourth. Furthermore, RV afterload elevations progressively upward shifted RV-EDPDR, whilst LV afterload elevations did not change LV-EDPDR. SERCA2a and phospholamban mRNA were similar in both ventricles. NCX-mRNA was almost 50% lower in RV than in LV. Left ventricular afterload elevations, therefore, accelerated the pressure fall and did not induce diastolic dysfunction, indicating high LV diastolic tolerance to afterload. On the contrary, RV afterload elevations decelerated the late RV pressure fall and induced diastolic dysfunction, indicating small RV diastolic tolerance to afterload. These results support previous findings relating NCX with late Ca2+ reuptake, late relaxation and diastolic dysfunction

Differential right and left ventricular diastolic tolerance to acute afterload and NCX gene expression in Wistar rats

This study evaluated right ventricular (RV) and left ventricular (LV) diastolic tolerance to afterload and SERCA2a, phospholamban and sodium-calcium exchanger (NCX) gene expression in Wistar rats. Time constant tau and end-diastolic pressure-dimension relation (EDPDR) were analyzed in response to progressive RV or LV afterload elevations, induced by beat-to-beat pulmonary trunk or aortic root constrictions, respectively. Afterload elevations decreased LV-tau, but increased RV-tau. Whereas LV-tau analyzed the major course of pressure fall, RV-tau only assessed the last fourth. Furthermore, RV afterload elevations progressively upward shifted RV-EDPDR, whilst LV afterload elevations did not change LV-EDPDR. SERCA2a and phospholamban mRNA were similar in both ventricles. NCX-mRNA was almost 50% lower in RV than in LV. Left ventricular afterload elevations, therefore, accelerated the pressure fall and did not induce diastolic dysfunction, indicating high LV diastolic tolerance to afterload. On the contrary, RV afterload elevations decelerated the late RV pressure fall and induced diastolic dysfunction, indicating small RV diastolic tolerance to afterload. These results support previous findings relating NCX with late Ca2+ reuptake, late relaxation and diastolic dysfunction

Salmonella sp. in pigs’ skin, external and internal carcass surface at slaughterhouse

Salmonella spp. is one of the major foodborne pathogen in Europe, being pork meat the second main vehicle of human infection. In this study it was analysed the occurrence of Salmonella spp. on pigs’ skin and in the respective carcasses surfaces (internal and external). For that, matched samples were collected in 120 animals. In each animal, sponge swabs were performed on the skin and in the corresponding carcass surfaces (approximate area 1000 cm2). A total of 360 samples were microbiologically analyzed according to ISO 6579. Salmonella isolates (45) were serotype by Kauffmann-White scheme at the National Reference Laboratory for Salmonella in Portugal. The main serotype identified was the monophasic variant of S. Typhimurium: S. 4,[5],12:i:- (46.7%), followed by S. Rissen (42.2%) and S. Derby (11.1%). The highest value of Salmonella occurrence was observed in pigs’ skin (29.2%; 35/120) underlining its importance as a potential source of Salmonella contamination to slaughterhouse. Nevertheless, since from these 34 pigs, only 2 presented this bacteria in the respective carcass external surface, the achieved results minimizes its importance for the direct contamination of the respective carcass. Salmonella sp. occurred more in the internal carcass surface (13.3 %; 16/120) than in the external (4.1%; 5/120) and, only in two cases, Salmonella sp. was simultaneously found in both carcass surfaces, equating different contamination sources. Curiously, S. 4,[5],12:i:-, a preoccupant serotype, was only identified in the pigs’ skin (12/34; 35.3%) and in the internal carcass surface (9/16; 56.3%). In these pigs, 4 presented simultaneously this serotype in both matched samples. This study suggest that more attention should be dedicated the skin as an important source of Salmonella contamination and to the internal carcass surface, which analysis is not under mandatory control defined in the Commission Regulation 2073⁄2005

Feasibility of remotely-supervised tDCS in a person with neuropathic pain due to spinal cord injury

[Excerpt] Nearly 40% of people with spinal cord injury (SCI) report neuropathic pain that is often refractory to medications.1,2 Substantial research has shown that anodal transcranial direct current stimulation (tDCS) over the motor cortex can induce clinically significant pain relief in chronic pain.3–6 However, these clinical trials often require multiple study visits per trial and are associated to poor adherence to the study protocol. For instance, in our recent tDCS study in SCI, only 7 participants from the initial 46 that were enrolled completed the study.7 In fact, despite all attempts to improve adherence, such as flexibility to schedule sessions, free parking and follow-ups by the phone, most participants ended up dropping out from the study. Since many people with SCI have limited mobility, alternatives for home-based care are needed. Here we report the feasibility of supervised home-based tDCS application in a 57-year old woman with tetraplegia and sublesional neuropathic pain secondary to SCI since 2012. At time of enrollment, she self-reported pain as being 9 out of 10 in a visual analogue scale. [...]This project was supported by the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant numbers 90DP0035 and H133N110010)

Combinatory approach for developing silk fibroin-based scaffolds with hierarchical porosity and enhanced performance for cartilage tissue engineering applications

Introduction: The combination of several processing technologies can open the possibility for producing scaffolds with superior performance for tissue engineering (TE) applications. Hydrogels are structurally similar to the natural extracellular matrix microenvironment presenting high elasticity and resistance to compression forces. They have been extensively used in biomedical devices fabrication and for TE applications, including for cartilage defects repair[1]. Recently, it was found that proteins like silk fibroin (SF), presenting tyrosine groups can be used to prepare fast formed hydrogels with controlled gelation properties, via an enzyme-mediated cross-linking reaction using horseradish peroxidase (HRP) and hydrogen peroxide (H2O2)[2],[3]. Moreover, the high versatility, processability and tailored mechanical properties of SF, make this natural polymer attractive for the development of innovative scaffolding strategies for cartilage TE applications[4],[5]. Materials and Methods: The present work proposes a novel route for developing SF-based scaffolds derived from high- concentrated SF (16wt%) enzymatically cross-linked by a HRP/H2O2 complex. The combination of salt-leaching and freeze-drying methodologies was used to prepare macro/microporous SF scaffolds with an interconnected structure and specific features regarding biodegradation and mechanical properties (Fig. 1a). The scaffolds morphology and porosity were analyzed by SEM and micro-CT. The mechanical properties (Instron) and protein conformation (FTIR, XRD) were also assessed. In order to evaluate the scaffolds structural integrity, swelling ratio and degradation profile studies were performed for a period of 30 day. This work also aims to evaluate the in vitro chondrogenic differentiation response by culturing human adipose derived stem cells (hASCs) over 21 days in basal and chondrogenic conditions. Cell behaviour in the presence of the macro/microporous structures will be evaluated through different quantitative (Live/Dead, DNA, GAGs, RT PCR) and qualitative (SEM, histology, immunocytochemistry) assays. Results and Discussion: The macro/microporous SF scaffolds showed high porosity and interconnectivity with the trabecular structures evenly distributed (Fig. 1b,c). A dramatic decrease of compressive modulus was observed for samples in hydrated state. Chemical analysis revealed that SF scaffolds displayed the characteristic peaks for β-sheet conformation. Swelling ratio data demonstrated a large swelling capacity, maintaining their structural integrity for 30 days. As expected, when immersed in protease XIV the degradation rate of SF scaffolds increased. Based on the promising morphology and physicochemical properties of the developed SF scaffolds, in vitro chondrogenic differentiation studies with hASCs are envisioned in order to validate their performance for cartilage regeneration applications. Conclusion: This study proposes an innovative approach to produce fast-formed porous SF scaffolds using enzymatically cross- linked SF hydrogels structured by the combination of salt-leaching and freeze-drying methodologies. The obtained results can provide a valuable reference of SF as a tunable and versatile biomaterial with great potential for applications in cartilage TE scaffolding. Portuguese Foundation for Science and Technology (FCT) project PEst-C/SAU/LA0026/201; ERDP funding through POCTEP Project 0687_NOVOMAR_1_P; Investigator FCT program IF/00423/2012 and IF/00411/2013 References: [1] Xia, L.-W., R. Xie, X.-J. Ju, W. Wang, Q. Chen, and L.-Y. Chu, Nano-structured smart hydrogels with rapid response and high elasticity. Nature communications, 2013. 4. [2] Sofia, S.J., A. Singh, and D.L. Kaplan, Peroxidase-catalyzed crosslinking of functionalized polyaspartic acid polymers. Journal of Macromolecular Science, Part A, 2002. 39(10): p. 1151-1181. [3] Reis, R.L., L.-P. Yan, A.L. Oliveira, J.M. Oliveira, D.R. Pereira, C. Correia, and R.A. Sousa, Hydrogels derived from silk fibroin: Methods and uses thereof. 2014. 107426. [4] Chen, C.-H., J.M.-J. Liu, C.-K. Chua, S.-M. Chou, V.B.-H. Shyu, and J.-P. Chen, Cartilage tissue engineering with silk fibroin scaffolds fabricated by indirect additive manufacturing technology. Materials, 2014. 7(3): p. 2104-2119. [5] Yan, L.-P., J.M. Oliveira, A.L. Oliveira, S.G. Caridade, J.F. Mano, and R.L. Reis, Macro/microporous silk fibroin scaffolds with potential for articular cartilage and meniscus tissue engineering applications. Acta biomaterialia, 2012. 8(1): p. 289-301.Â

Embryonal rhabdomyosarcoma of the uterine cervix: a rare case report

Embryonal rhabdomyosarcoma of the female genital tract is a rare tumour. It tends to occur during childhood in the vagina and, rarely, it can arise in the uterine cervix, with a peak incidence in the second decade. We report a case of a 18-year-old female with an embryonal rhabdomyosarcoma (sarcoma botryoides) presenting himself as a cervical polyp. This tumour consisted of rhabdomyoblasts with miscellaneous differentiation surrounded by a loose, myxoid stroma. The patient was successfully treated with cervical conization and adjuvant chemotherapy. She is now disease-free at the 28th month follow-up. Awareness of this uncommon lesion in the cervix and its clinical implications is important to prevent misdiagnosis. Therapy has recently inclined to conservative and fertility-sparing treatment