266 research outputs found
Efficient and low cytotoxicity gene carriers based on amine-functionalized polyvinylpyrrolidone
Non-viral vectors are a safety tool for gene therapy to deliver therapeutic genes. Among the different non-viral vectors, polyvinylpyrrolidone (PVP), a well-known hydrosoluble, neutral, and non-toxic polymer, satisfies the requirements and becomes a suitable candidate for gene delivery. In this study, we describe the preparation of polyvinylpyrrolidones decorated with pyrrolidine, piperidine, and piperazine groups, and evaluate them in vitro as non-viral gene carriers. The properties of these new systems are compared with those of hyperbranched polyethyleneimine (PEI) used as a positive control. Their ability to complex DNA at different N/P molar ratios, from 1:1 up to 10:1, was studied through agarose gel electrophoresis and dynamic light scattering. The resulting complexes (polyplexes) were characterized and evaluated in vitro with murine fibroblast (Swiss 3T3) as non-viral gene carriers, using luciferase as the reporter gene and a calcein cytocompatibility assay. All the copolymers condensed DNA to a particle average size between 100–400 nm when used at N/P ratios of 4:1 or higher. The copolymers with piperidine groups showed higher transfection efficiency than the pyrrolidine and piperazine modified copolymers, and even higher than the positive control of PEI at N/P ratios of 4:1 or higher. All the synthesized polyplexes from an aminated PVP displayed a general tendency of high cytocompatibility (75–95%) in comparison with the positive control PEI (55%)
Transcriptional organization and regulation of the Pseudomonas putida K1 type VI secretion system gene cluster
The type VI secretion system (T6SS) is an antimicrobial molecular weapon that is widespread in Proteobacteria and offers competitive advantages to T6SS-positive micro-organisms. Three T6SSs have recently been described in Pseudomonas putida KT2440 and it has been shown that one, K1-T6SS, is used to outcompete a wide range of phytopathogens, protecting plants from pathogen infections. Given the relevance of this system as a powerful and innovative mechanism of biological control, it is critical to understand the processes that govern its expression. Here, we experimentally defined two transcriptional units in the K1-T6SS cluster. One encodes the structural components of the system and is transcribed from two adjacent promoters. The other encodes two hypothetical proteins, the tip of the system and the associated adapters, and effectors and cognate immunity proteins, and it is also transcribed from two adjacent promoters. The four identified promoters contain the typical features of σ70-dependent promoters. We have studied the expression of the system under different conditions and in a number of mutants lacking global regulators. P. putida K1-T6SS expression is induced in the stationary phase, but its transcription does not depend on the stationary σ factor RpoS. In fact, the expression of the system is indirectly repressed by RpoS. Furthermore, it is also repressed by RpoN and the transcriptional regulator FleQ, an enhancer-binding protein typically acting in conjunction with RpoN. Importantly, expression of the K1-T6SS gene cluster is positively regulated by the GacS–GacA two-component regulatory system (TCS) and repressed by the RetS sensor kinase, which inhibits this TCS. Our findings identified a complex regulatory network that governs T6SS expression in general and P. putida K1-T6SS in particular, with implications for controlling and manipulating a bacterial agent that is highly relevant in biological control
Refugee Women’s Experiences of Violence and Resilience: Early Explorations
Refugee experiences of violence are well known and may include violence in the country of origin, in refugee camps, countries of detention and, especially for women and children, in their own families before and after resettlement. The resilience of former refugees to violence has been noted in recent times by a range of agencies. Across Australia, a number of initiatives are in place to deal with experiences of violence in these communities, including policing programs, settlement support services, community support groups and torture and trauma survival services. This paper will report on the preliminary findings of a qualitative project investigating the relationship between refugee women, violence and resilience in the context of resettlement. Focusing on interviews with service providers, the paper will explore how resilience is understood within, and may impact on, service provision.Sydney Institute of Criminology; School of Social Sciences at the University of Western Sydne
Metastatic Squamous Cell Carcinoma to the Cervical Lymph Nodes From an Unknown Primary Cancer : Management in the HPV Era
Background Patients with metastases in the lymph nodes of the neck and no obvious primary tumor, neck cancer with unknown primary (NCUP), represent a management challenge. A majority of patients have metastatic squamous cell carcinoma (SCC), although other histologies do occur. Methods We comprehensively reviewed the literature, compared available guidelines, and conferred with an international team of experts. Results Positron emission tomography-computed tomography (PET-CT) and fine needle aspiration (FNA) under ultrasound guidance increase accuracy of diagnosis. Immunohistochemistry (IHC), determination of human papilloma virus (HPV) status, by p16 staining or by in situ hybridization (ISH), and next-generation gene sequencing can guide us regarding probable primary sites and tumor biology. Narrow Band Imaging (NBI) has been introduced for the early detection of subtle mucosal lesions. Direct laryngoscopy (DL) and tonsillectomy have long been procedures used in the search for a primary site. More recently, TransOral Robotic Surgery (TORS) or Transoral LASER Microsurgery (TLM) have been introduced for lingual tonsillectomy. Conclusions New technologies have been developed which can better detect, diagnose, and treat occult primary tumors. Decisions regarding therapy are based on the primary tumor site (if discovered) and N stage. Options include neck dissection with or without postoperative adjuvant therapy, primary irradiation, or combined chemotherapy with irradiation. The preferred treatment of patients whose primary remains unidentified is controversial.Peer reviewe
What is the role of sentinel lymph node biopsy in the management of oral cancer in 2010?
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Early Postoperative Monitoring of the Liver Graft
Liver transplantation (LT) is a common current technique for end-stage liver disease. Complications after the surgical procedure, though uncommon, can be of very different origin and can also be severe enough to lead to liver and multiorgan failure and finally graft loss and/or recipient’s death. Intensivists and the surgical team must be familiarized with these early complications to detect them as soon as possible in order to use the best diagnostic tools and take the best therapeutic measures to restore anatomical integrity and organ function to optimize the liver graft. In this chapter, we present an updated state of the art for efficiently tackling with all different, most usual complications that an LT patient can present during early postoperative period
Proximal and distal deep venous thrombosis in critically ill patients: incidence and prevalence
The Activity of the Pseudomonas aeruginosa Virulence Regulator σVreI Is Modulated by the Anti-σ Factor VreR and the Transcription Factor PhoB
Gene regulation in bacteria is primarily controlled at the level of transcription initiation by modifying the affinity of the RNA polymerase (RNAP) for the promoter. This control often occurs through the substitution of the RNAP sigma (σ) subunit. Next to the primary σ factor, most bacteria contain a variable number of alternative σ factors of which the extracytoplasmic function group (σECF) is predominant. Pseudomonas aeruginosa contains nineteen σECF, including the virulence regulator σVreI. σVreI is encoded by the vreAIR operon, which also encodes a receptor-like protein (VreA) and an anti-σ factor (VreR). These three proteins form a signal transduction pathway known as PUMA3, which controls expression of P. aeruginosa virulence functions. Expression of the vreAIR operon occurs under inorganic phosphate (Pi) limitation and requires the PhoB transcription factor. Intriguingly, the genes of the σVreI regulon are also expressed in low Pi despite the fact that the σVreI repressor, the anti-σ factor VreR, is also produced in this condition. Here we show that although σVreI is partially active under Pi starvation, maximal transcription of the σVreI regulon genes requires the removal of VreR. This strongly suggests that an extra signal, probably host-derived, is required in vivo for full σVreI activation. Furthermore, we demonstrate that the activity of σVreI is modulated not only by VreR but also by the transcription factor PhoB. Presence of this regulator is an absolute requirement for σVreI to complex the DNA and initiate transcription of the PUMA3 regulon. The potential DNA binding sites of these two proteins, which include a pho box and −10 and −35 elements, are proposed.This work has been supported by the EU Seventh Framework Programme through a Marie Curie CIG grant (3038130), and the Spanish Ministry of Economy with grants inside the Ramón&Cajal (RYC2011-08874 to ML) and the Plan Nacional for I+D+i (SAF2012-31919 and SAF2015-68873-P) programs.USD 2212,20 APC fee funded by the EC FP7 Post-Grant Open Access PilotPeer reviewe
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