New Fully Biodegradable PEG-Dendrimers: Synthesis and evaluation as siRNA vectors

Gene therapy has been proposed as a powerful approach to treat/prevent several diseases. The original concept consisted in the insertion of exogenous DNA in cells to correct genetic diseases. Currently, the concept has been broadened and other strategies have been reported, such as the promising use of small interfering RNA (siRNA) for the short-term down-regulation of protein expression. However, gene therapy requires the development of clinically suitable, effective, and biocompatible vectors to carry the nucleic acid (NA). Dendrimers are promising NA vectors due to their globular, well-defined, and highly branched, low polydispersity, the presence of terminal groups that can be multifunctionalized with different ligands, and their ability to complex and protect NAs in nanostructures (“dendriplexes”). However, one important drawback of most used dendrimers applied biomedically is their non-degradability under physiological conditions that can result in cytotoxicity induced by non-degradable synthetic materials in the organism. Moreover, biodegradability can be useful since it will favour the siRNA release, leading to higher transfection efficiencies. Here, we report a new family of fully biodegradable, biocompatible, and non-toxic PEG-dendritic block copolymers to act as NA vectors. These novel fully biodegradable PEG-dendrimers allowed the efficient complexation and mediation of siRNA internalization, showing excellent transfection efficiencies

Biodegradable PEG–dendritic block copolymers: synthesis and biofunctionality assessment as vectors of siRNA

One important drawback of most of the currently used dendrimers for biomedical applications is their high stability under physiological conditions that can result in cytotoxicity or complications induced by the accumulation of non-degradable synthetic materials in the organism. Particularly in the gene therapy field, vector stability can further hinder the intracellular release of the nucleic acid from the dendriplex, consequently leading to low transfection efficiencies. Therefore, biodegradable cationic dendritic structures have been eagerly awaited. However, the development of these dendritic nanocarriers is challenging because of the undesired and/or premature degradation observed during their synthesis and/or application. Here, we report new hybrid-biodegradable, biocompatible, non-toxic, and water-soluble azide-terminated PEG–GATGE dendritic block copolymers, based on a gallic acid (GA) core and triethylene glycol (TG) butanoate arms, incorporating ester bonds (E) at the dendritic arms/shell. Their successful functionalization by “click” chemistry with unprotected alkynated amines allowed complexation and delivery of siRNA. The hydrophobic character of the GATGE building unit confers to these hydrolyzable dendritic bionanomaterials a great ability to complex, protect and mediate the cellular internalization of siRNA. Moreover, the localization of the degradation points at the dendritic periphery, close to the complexed siRNA, was found to be important for nucleic acid release from the nanoparticles, rendering a significant improvement of the transfection efficiency compared to their hydrolytically stable PEG–GATG copolymer counterparts. The present study puts forward these biodegradable PEG–dendritic block copolymers not only as suitable vectors for nucleic acids, but also as new avenues for further developments exploring their use in theranosticsThe authors would like to acknowledge the FEDER funds through the Programa Operacional Factores de Competitividade – COMPETE and the Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia (PTDC/CTM-NAN/112428/2009 and PTDC/CTM-NAN/3547/2014) that supported this work and the FCT / MEC through National Funds and, when applicable, co-financed by the FEDER via the PT2020 Partnership Agreement under the 4293 Unit I&D. V. Leiro acknowledges the support by FCT (SFRH/BPD/69110/2010) and by the project NORTE-01-0145-FEDER-000012, financed by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). P.M.D. Moreno acknowledges the support from the Marie Curie Actions of the European Community’s Seventh Framework Program (PIEF-GA-2011-300485) and FCT fellowship (SFRH/BPD/108738/2015). This work was also financially supported by the Spanish Government (MINECO: CTQ2012-34790, CTQ2012-33436) and the Xunta de Galicia (CN2011/037)S

Comparison of histological and molecular diagnosis of Helicobacter pylori in benign lesions and gastric adenocarcinoma

A colonização do Helicobacter pylori está associada com gastrite crônica, úlcera péptica, metaplasia intestinal, adenocarcinoma e linfoma gástrico. O objetivo desse estudo foi comparar os resultados do diagnóstico histológico usado de rotina na detecção do H. pylori com o diagnóstico molecular. Foram utilizadas amostras de 80 lesões gástricas (gastrite crônica, gastrite atrófica, úlcera gástrica e metaplasia intestinal), 18 amostras de adenocarcinoma gástrico e 10 amostras de mucosa gástrica normal H. pylori negativas (controle). Todas as amostras foram avaliadas histologicamente (coloração com hematoxilina-eosina e Giemsa) e pela PCR com a amplificação dos genes antígeno espécie-específico (H3H4) e urease A (H5H6) do H. pylori e pelo gene humano CYP1A1, como controle da qualidade do DNA. Nas amostras de lesão benigna e adenocarcinoma gástrico, a infecção foi detectada em 43% (42/98) e 71% (70/98), respectivamente, para os diagnósticos histológico e molecular (p = 0,0001). O teste de PCR detectou o H. pylori em 27,5% (22/80) das lesões gástricas benignas e em 50% (9/18) dos adenocarcinomas gástricos, com diagnóstico histológico negativo para essa bactéria. Cerca de 2,5% das amostras, exclusivamente de lesões benignas, com diagnóstico histológico positivo apresentaram resultado molecular negativo, para ambos os primers. Diferenças estatisticamente significantes foram encontradas entre os métodos histológico e molecular, em metaplasia intestinal (p = 0,0461) e adenocarcinoma gástrico (p = 0,0011), devido à subdetecção do H. pylori pelo método histológico, e provavelmente pela baixa densidade da bactéria conseqüente à atrofia severa da mucosa gástrica, nesses dois tipos de lesões. Nossos achados demonstram que o método de PCR é mais eficaz para diagnosticar a infecção por H. pylori, principalmente, em metaplasia intestinal e adenocarcinoma gástrico.Helicobacter pylori colonization is associated with chronic gastritis, peptic ulcers, intestinal metaplasia, adenocarcinoma and lymphoma of the stomach. The objective of this study was to compare the results of the routinely used histology with molecular diagnosis for the detection of H. pylori. Eighty samples from gastric lesions (chronic gastritis, atrophic gastritis, gastric ulcer, and intestinal metaplasia), 18 gastric adenocarcinoma and 10 normal mucosa H. pylori-negative (control) samples were obtained. All samples were examined histologically (hematoxylin-eosin and Giemsa staining), and PCR amplifications of the species-specific antigen gene (H3H4) and urease A gene segment (H5H6) of H. pylori were made, using the human gene CYP1A1 for DNA quality control. In the benign lesion and adenocarcinoma the infection was detected in 43% (42/98) and 71% (70/98) by histological and molecular diagnosis (p = 0.0001), respectively. The PCR test detected H. pylori in 27.5% (22/80) of the benign gastric lesions and in 50% (9/18) of the gastric adenocarcinoma cases, the histological diagnosis being negative for this bacterium. About 2.5% of the samples, exclusively from benign lesions and with a positive histological diagnosis, showed negative molecular results for both primers. Statistically significant differences were found between the histological and the molecular method in intestinal metaplasia (p = 0.0461) and gastric adenocarcinoma (p = 0.0011), due to underdetection of H. pylori by the histological method, which is probably due to the low density of the bacterium as a consequence of the severe atrophy of the gastric mucosa. Our findings suggest that PCR is the more efficient method for the assessment of H. pylori infection, especially in metaplasia and gastric adenocarcinoma.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Are TQM principles supporting innovation in the Portuguese footwear industry?

The relationship between total quality management (TQM) and innovation is complex. Literature suggests that conflicting arguments exist and that the impact of TQM on innovation depends both on the specific quality management elements under consideration and on the type of innovation. In this research, our goal is to analyse at what extent the introduction of TQM is indeed supporting innovation in the Portuguese footwear industry. Since this is a mature industry, whose traditional competitive base is disappearing and where familiar to medium units dominate, our emphasis is on the study of the organisational requirements to adopt constant changes in process technology. This study is based on empirical data collected from a set of firms by means of a survey instrument, especially developed with this purpose, after an extended contact with the industry where case studies and interviews were conducted with carefully selected organisations and sector experts. Findings give support to the view that in fact TQM principles have a positive association with the adoption of technological innovation. Yet, both the prevalence of features of the mechanistic model and the lack of maturity of most initiatives in the Portuguese footwear firms restrains the role of TQM in supporting innovation.http://www.sciencedirect.com/science/article/B6V8B-4R003DV-1/1/4e2ee16f993a27bf9df8da43f42c59c