ABSTRACT
Potassium niobate nonlinear nanoparticles are used for the first time to monitor the evolution of embryonic stem cells (ESC) by second harmonic microscopy. These particles feature the complete absence of photo-bleaching and unlimited excitation wavelength flexibility. The potential of this approach is made evident for tissue-regeneration studies and applications, by capturing a high-speed movie of ESC-derived cardiomyocytes autonomously beating within a cluster. Time-resolved data are analyzed to retrieve 3D information of the contraction pattern at the cellular level.
Subject(s)
Embryonic Stem Cells/cytology , Myocardium/cytology , Nanotechnology , Animals , MiceABSTRACT
Nonlinear optical nanocrystals have been recently introduced as a promising alternative to fluorescent probes for multiphoton microscopy. We present for the first time a complete survey of the properties of five nanomaterials (KNbO(3), LiNbO(3), BaTiO(3), KTP, and ZnO), describing their preparation and stabilization and providing quantitative estimations of their nonlinear optical response. In the light of their prospective use as biological and clinical markers, we assess their biocompatibility on human healthy and cancerous cell lines. Finally, we demonstrate the great potential for cell imaging of these inherently nonlinear probes in terms of optical contrast, wavelength flexibility, and signal photostability.
Subject(s)
Materials Testing , Nanoparticles/chemistry , Nanoparticles/toxicity , Optical Phenomena , Barium Compounds/chemistry , Barium Compounds/toxicity , Cell Line, Tumor , Colloids , Hemolysis/drug effects , Humans , Hydrogen-Ion Concentration , Molecular Imaging , Niobium/chemistry , Niobium/toxicity , Oxides/chemistry , Oxides/toxicity , Phosphates/chemistry , Phosphates/toxicity , Photons , Polyethylene Glycols/chemistry , Potassium/chemistry , Potassium/toxicity , Staining and Labeling , Titanium/chemistry , Titanium/toxicity , Water/chemistry , Zinc Oxide/chemistry , Zinc Oxide/toxicityABSTRACT
We demonstrate the possibility to excite second-harmonic (SH) active Fe(IO(3))(3) nanocrystals with two distinct laser sources at 800 and 1550 nm, and we show, by a complementary experimental and numerical study, how the wavelength flexibility inherent to non-phase-matched SH nanoparticles can be efficiently exploited to increase imaging penetration depth of markers embedded in biological samples.
Subject(s)
Microscopy, Fluorescence, Multiphoton/methods , Nanotechnology/methods , Animals , Computer Simulation , Iron/chemistry , Lasers , Mice , Microscopy/methods , Monte Carlo Method , Nanoparticles/chemistry , Nephelometry and Turbidimetry/methods , Optics and Photonics , Photons , Polystyrenes/chemistryABSTRACT
To investigate the potential benefits of two modes of evidence-based knowledge transfer ('active' and 'passive' modes) in terms of improvement of intention of prescription, knowledge, and real prescription in practice, we performed an open randomized controlled trial (CardioDAS) using a factorial design (two tested interventions: 'active' and 'passive' knowledge transfer) and a hierarchical structure (cluster of physicians for each department level). The participants were cardiologists working in French public hospitals. In the 'passive' transfer group, cardiologists received evidence-based knowledge material (available on Internet) every week for a duration of 1 year. In the 'active' transfer group, two knowledge brokers (EA, PN) visited the participating departments (every 2 months for 1 year, 2 h per visit). The primary outcome consisted in the adjusted absolute mean variation of score (difference between post- and pre-study session) of answers to simulated cases assessing the intention to prescribe. Secondary outcomes were the variation of answers to a multiple-choice questionnaire (MCQ) assessing knowledge and of the conformity of real prescriptions to evidence-based reference assessing the behavioral change. Twenty-two French units (departments) of cardiology were randomized (72 participating cardiologists). In the 'active' transfer group, the primary outcome was more improved than that in the control (P = 0.031 at the department level, absolute mean improvement of 5 points/100). The change in knowledge transfer (MCQ) was also significant (P = 0.039 at the department level, absolute mean improvement of 6 points/100). However, no benefit was shown in terms of prescription conformity to evidence. For the 'passive' mode of knowledge transfer and for the three outcomes considered, no improvement was identified. CardioDAS findings confirm that 'active' knowledge transfer has some impact on participants' intent to prescribe and knowledge, but no effect on behavioral outcome. 'Passive' transfer seems far less efficient. In addition, the size of the benefit remains small and its consequences limited in practice.
Subject(s)
Cardiology/education , Education, Medical, Continuing/methods , Evidence-Based Medicine/education , Knowledge , HumansABSTRACT
CONTEXT: The Standards, Options and Recommendations (SOR) project, started in 1993, is a collaboration between the Federation of French Cancer Centres (FNCLCC), the 20 French cancer centres, and specialists from French public universities, general hospitals and private clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and the outcome of cancer patients. The methodology is based on a literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVES: To establish the Standards, Options and Recommendations clinical practice guidelines for the management of procedure related pain (lumbar puncture, bone marrow aspiration or biopsy, blood sampling) in children oncology patients. To define, on the basis of the critical appraisal of the best available evidence and expert agreement, the clinical situations in which a pain preventive strategy should be implemented. METHODS: MEDLINE was searched using specific search strategies from January 1966 to August 2004. Literature monitoring was performed to identify controlled clinical trials published in 2005. RESULTS: A total of 57 references were identified. Clinical guidelines have been defined for each invasive procedure.
Subject(s)
Pain Management , Punctures/adverse effects , Biopsy/adverse effects , Biopsy, Fine-Needle/adverse effects , Bone Marrow Examination/adverse effects , Child , Humans , Pain/etiology , Phlebotomy/adverse effects , Spinal Puncture/adverse effectsABSTRACT
From a general review of the literature on breast cancer screening, authors appointed by the parliament office for healthcare policy assessment (Office Parlementaire d'Evaluation des Politiques de Santé, OPEPS) demonstrate that, despite recent controversies, screening is both medically and economically effective. The organisation and specifications of screening are considered. The French situation is examined in the light of European recommendations and compared to other systems in place. After analysing the outcome of screening, particularly the results of the 2003 Cancer Plan, the authors considered the risks of screening, and the type of information given to women.