Stem cells in skin wound healing: are we there yet?

Significance: Cutaneous wound healing is a serious problem worldwide that affects patients with various wound types, resulting from burns, traumatic injuries, and diabetes. Despite the wide range of clinically available skin substitutes and the different therapeutic alternatives, delayed healing and scarring are often observed. Recent Advances: Stem cells have arisen as powerful tools to improve skin wound healing, due to features such as effective secretome, self-renewal, low immunogenicity, and differentiation capacity. They represent potentially readily available biological material that can particularly target distinct wound-healing phases. In this context, mesenchymal stem cells have been shown to promote cell migration, angiogenesis, and a possible regenerative rather than fibrotic microenvironment at the wound site, mainly through paracrine signaling with the surrounding cells/tissues. Critical Issues: Despite the current insights, there are still major hurdles to be overcome to achieve effective therapeutic effects. Limited engraftment and survival at the wound site are still major concerns, and alternative approaches to maximize stem cell potential are a major demand. Future Directions: This review emphasizes two main strategies that have been explored in this context. These comprise the exploration of hypoxic conditions to modulate stem cell secretome, and the use of adipose tissue stromal vascular fraction as a source of multiple cells, including stem cells and factors requiring minimal manipulation. Nonetheless, the attainment of these approaches to target successfully skin regeneration will be only evident after a significant number of in vivo works in relevant pre-clinical models.L3–TECT—NORTE-01-0124-FEDER-000020’’ cofinanced by North Portugal Regional Operational Program (ON.2—O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF), and Portuguese Foundation for Science and Technology (FCT

Erbium-doped silicon nanocrystals grown by r.f. sputtering method: competition between oxygen and silicon to get erbium

Erbium doped micro- and nanocrystalline silicon thin films have been deposited by co-sputtering of Er and Si. Films with different crystallinity, crystallite size, hydrogen and oxygen content have been obtained in order to investigate the effect of the microstructure and composition of matrix on the near IR range at 1.54 µm Er-related photoluminescence (PL) properties. The correlation between the optical properties and microstructural parameters of the films is investigated using spectroscopic ellipsometry. It is found that the luminescent properties of these composite films can be understood on the basis of the ellipsometric analysis that reveals the films heterogeneous structure, and that Er-related PL dominates in films with 1-3 nm sized Si nanocrystals embedded in a-Si:H.INTAS Project #03-51-6486Fundação para a Ciência e a Tecnologia Project POCTI/CTM/39395/200

Interfollicular epidermal stem cells: boosting and rescuing from adult skin

Publicado na série "Methods in Molecular Biology", vol. 989 (2013), ISSN 1064-3745Epidermal stem cells isolation struggle remains, mainly due to the yet essential requirement of well-defined approaches and markers. The herein proposed methodology integrates an assemblage of strategies to accomplish the enrichment of the interfollicular epidermal stem cells multipotent fraction and their subsequent separation from the remaining primary human keratinocytes culture. Those include rapid adherence of freshly isolated human keratinocytes to collagen type IV through the β 1-integrin ligand and Rho- Associated Protein Kinase Inhibitor Y- 27632 administration to the cultures, followed by an immunomagnetic separation to obtain populations based in the combined CD49f bri /CD71 dim expression. Flow cytometry is the supporting method to analyze the effect of the treatments over the expression rate of early epidermal markers keratins19/5/14 and in correlation to CD49f bri /CD71 dim subpopulations. The stepby- step methodology herein described indulges the boosting and consecutive puri fi cation and separation of interfollicular epidermal stem cells from human keratinocytes cultures.(undefined

Híbridos de bananeira ornamental com potencial para paisagismo.

Ao longo dos últimos anos, a floricultura brasileira vem adquirindo notável desenvolvimento e se caracteriza como um dos mais promissores segmentos da horticultura intensiva no campo dos agronegócios nacionais (JUNQUEIRA; PEETZ, 2008). Um dos aspectos que contribui para a expansão são as condições climáticas do Brasil que favorecem o cultivo de flores, tanto de clima temperado como tropical (FRANÇA; MAIA, 2008)

Effect of grain size and hydrogen passivation on the electrical properties of nanocrystalline silicon films

The properties of mixed-phase (nanocrystalline/amorphous) silicon layers produced by reactive RF-sputtering are described. The chemical composition and nanostructure [i.e. nanocrystal (NC) size and volume fraction] of the films were studied by Rutherford backscattering spectroscopy (RBS) and micro-Raman spectroscopy, respectively. Samples with different fractions of the nanocrystalline phase and NC mean size were produced by changing the deposition parameters, without post-growth annealing. The electrical conductivity of the films, measured as function of temperature, is discussed in relation to their nanostructureFCT Project POCTI/CTM/39395/200

Magnetic Field Effects on the Head Structure of Protostellar Jets

We present the results of 3-D SPMHD numerical simulations of supermagnetosonic, overdense, radiatively cooling jets. Two initial magnetic configurations are considered: (i) a helical and (ii) a longitudinal field. We find that magnetic fields have important effects on the dynamics and structure of radiative cooling jets, especially at the head. The presence of a helical field suppresses the formation of the clumpy structure which is found to develop at the head of purely hydrodynamical jets. On the other hand, a cooling jet embedded in a longitudinal magnetic field retains clumpy morphology at its head. This fragmented structure resembles the knotty pattern commonly observed in HH objects behind the bow shocks of HH jets. This suggests that a strong (equipartition) helical magnetic field configuration is ruled out at the jet head. Therefore, if strong magnetic fields are present, they are probably predominantly longitudinal in those regions. In both magnetic configurations, we find that the confining pressure of the cocoon is able to excite short-wavelength MHD K-H pinch modes that drive low-amplitude internal shocks along the beam. These shocks are not strong however, and it likely that they could only play a secondary role in the formation of the bright knots observed in HH jets.Comment: 14 pages, 2 Gif figures, uses aasms4.sty. Also available on the web page http://www.iagusp.usp.br/preprints/preprint.html. To appear in The Astrophysical Journal Letter

Group B Streptococcus rectovaginal colonization screening on term pregnancies: culture or polymerase chain reaction?

Objectives The aim of this study was to evaluate if screening Group B Streptococcus colonization by intrapartum polymerase chain reaction could improve intrapartum administration of antibiotic prophylaxis, compared with antepartum culture screening and analyze the sensitivity and specificity of polymerase chain reaction test. Methods 198 pregnant women with Group B Streptococcus colonization antepartum culture screening were included. When they arrived at hospital for delivery, two rectovaginal swabs were collected: for culture and polymerase chain reaction method. Results The rate of Group B Streptococcus colonization antepartum detected by culture was 16.7%; at delivery was 17.2% when detected by culture and 19.7% using polymerase chain reaction method. The rate of inconclusive polymerase chain reaction tests was 0.5%. Considering intrapartum culture screening as gold standard, sensitivity and specificity of polymerase chain reaction test for intrapartum Group B Streptococcus colonization was 97.1% and 95.7%, respectively. The global rate of discordance between antepartum and intrapartum Group B Streptococcus colonization was 6.6%. The rate of women not treated with intrapartum antibiotic prophylaxis in the setting of positive intrapartum culture was significantly lower using intrapartum polymerase chain reaction test (0.5%) than with antepartum culture method (3.5%, p = 0.035). Conclusion The use of intrapartum antibiotic prophylaxis can be more efficient when screening Group B Streptococcus colonization intrapartum by polymerase chain reaction test. Polymerase chain reaction method had a good performance in our study, with high sensitivity and specificity

Alterações físico-químicas durante o amadurecimento de Banana 'Prata Anã' em sete estádios de maturação.

A banana 'Prata Anã' é a variedade mais apreciada entre os brasileiros, fato comprovado pelo seu cultivo e sua boa aceitação comercial. A qualidade desses frutos constitui fator importante na comercialização, principalmente quando destinado ao consumo in natura. Desta forma, o objetivo foi avaliar as alterações físico-químicas que ocorrem durante os diferentes estádios de maturação da banana 'Prata Anã' cultivados na cidade de Cruz das Almas ? BA. Frutos foram avaliados diariamente quanto aos sete estádios de maturação estabelecidos na escala de Von Loesecke e avaliados em cada um dos estádios quanto a: perda de massa fresca; espessura da casca; relação polpa/casca; acidez titulável (AT); sólidos solúveis (SS) e relação SS/AT. Os resultados deste trabalho permitiram verificar que o amadurecimento dos frutos de ?Prata Anã? ocorre de maneira lenta durante os dois primeiros estádios, seguido de rápida transição e fortes alterações nas características físico-químicas da polpa entre os estádios 3 e 4. No entanto, o último estádio apresentou frutos com maior proporção de polpa e melhor balanço sólidos solúveis e acidez

Stromal vascular fraction from adipose tissue and cell sheet engineering to build vascularization units for tissue engineering and regenerative medicine

Vascularization holds the gold key for the effective survival and engraftment of complex engineered tissues and organs for Tissue Engineering and Regenerative Medicine. The lack of adequate vascularization post-transplantation often results in cell necrosis and ultimate failure and rejection of the engineered construct. Herein, we propose a strategy capable of surpassing this obstacle. Harnessing easy accessible adipose tissue stromal vascular fraction (SVF) as a source for cells with intrinsic angiogenic potential, and cell sheet technology we were able to engineer cell sheets with high angiogenic potential. SVF was isolated from the adipose tissue of healthy human subjects after enzymatic digestion and 2x105 nucleated cells/well were seeded on 24 well plates for cell sheet formation. To further boost cells’ angiogenic potential, hypoxic conditions of 5% of oxygen were provided to some of the cells while the rest was cultured in typical normoxia, for up to 8 days of culture, in basal medium. Flow cytometry analysis demonstrated the presence of a heterogeneous population of mesenchymal progenitors, endothelial and hematopoietic cells. Furthermore, the proliferation of SVF cells was evaluated through dsDNA quantification, which showed higher numbers for cells in hypoxic conditions, at earlier time points. Immunocytochemistry against CD31 and CD146 revealed the presence of an interconnected and highly branched network of vessel-like structures, more prominent for cells in hypoxia after 5 days of culture and quite similar for both conditions after 8 days, in the absence of any specific media supplementation. In vivo testing using the cell sheets detached from the wells and HIF expression analysis are currently underway. Taken together, the great potentiality of cell sheet technology with SVF cells cultured in hypoxia opens new exciting perspectives and may represent tremendously valuable vascularization units for tissue engineering strategies