Nanoparticles for Applications in Cellular Imaging

In the following review we discuss several types of nanoparticles (such as TiO2, quantum dots, and gold nanoparticles) and their impact on the ability to image biological components in fixed cells. The review also discusses factors influencing nanoparticle imaging and uptake in live cells in vitro. Due to their unique size-dependent properties nanoparticles offer numerous advantages over traditional dyes and proteins. For example, the photostability, narrow emission peak, and ability to rationally modify both the size and surface chemistry of Quantum Dots allow for simultaneous analyses of multiple targets within the same cell. On the other hand, the surface characteristics of nanometer sized TiO2allow efficient conjugation to nucleic acids which enables their retention in specific subcellular compartments. We discuss cellular uptake mechanisms for the internalization of nanoparticles and studies showing the influence of nanoparticle size and charge and the cell type targeted on nanoparticle uptake. The predominant nanoparticle uptake mechanisms include clathrin-dependent mechanisms, macropinocytosis, and phagocytosis

Imaging strategies in scanning optical microscopy

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Photoluminescence excitation spectroscopy yields bandgap of Ga_5In_5P containing relatively ordered domains

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Investigating Dimensions of Stiffness in Rheumatoid and Psoriatic Arthritis: The Australian Rheumatology Association Database Registry and OMERACT Collaboration

OBJECTIVE:It is not known how the experience of stiffness varies between diagnoses or how best to measure stiffness. The aims of our study were to (1) compare stiffness in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) using patient-reported outcomes, (2) investigate how dimensions of stiffness are associated with each other and reflect the patient experience, and (3) analyze how different dimensions of stiffness are associated with physical function. METHODS:An online survey was sent to Australian Rheumatology Association Database participants (158 PsA, and 158 age- and sex-matched RA), assessing stiffness severity, duration, impact, importance, coping, and physical function [modified Health Assessment Questionnaire (mHAQ)]. Scores were compared between diagnoses and correlations among stiffness dimensions calculated. Multivariate regression was performed for stiffness severity, impact, and duration on mHAQ, adjusting for age, sex, disease duration, obesity, and pain. Cognitive debriefing was conducted through semistructured telephone interviews. RESULTS:Overall, 240/316 (75.9%) responded [124/158 RA (78.5%) and 116/158 PsA (73.4%)], with no significant difference in stiffness ratings between diagnoses. Scores for all stiffness dimensions were strongly correlated (r = 0.52-0.89), and severity and impact were associated with mHAQ in both diagnoses. Stiffness duration was not associated with mHAQ in RA. In cognitive debriefing, participants described stiffness severity and impact by their effect on daily activities (10/16 and 14/16 participants, respectively). CONCLUSION:Stiffness ratings were similar between PsA and RA. Different dimensions of stiffness were strongly correlated. Stiffness severity and impact both independently predicted mHAQ. Stiffness was important to participants; however, measuring multiple dimensions of stiffness may have minimal additive value.Premarani Sinnathurai, Susan J. Bartlett, Serena Halls, Sarah Hewlett, Ana-Maria Orbai, Rachelle Buchbinder, Lyndall Henderson, Catherine L. Hill, Marissa Lassere, and Lyn Marc

Content and Construct Validity, Reliability, and Responsiveness of the Rheumatoid Arthritis Flare Questionnaire: OMERACT 2016 Workshop Report

Item does not contain fulltextOBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis (RA) Flare Group was established to develop a reliable way to identify and measure RA flares in randomized controlled trials (RCT). Here, we summarized the development and field testing of the RA Flare Questionnaire (RA-FQ), and the voting results at OMERACT 2016. METHODS: Classic and modern psychometric methods were used to assess reliability, validity, sensitivity, factor structure, scoring, and thresholds. Interviews with patients and clinicians also assessed content validity, utility, and meaningfulness of RA-FQ scores. RESULTS: People with RA in observational trials in Canada (n = 896) and France (n = 138), and an RCT in the Netherlands (n = 178) completed 5 items (11-point numerical rating scale) representing RA Flare core domains. There was moderate to high evidence of reliability, content and construct validity, and responsiveness. Factor analysis supported unidimensionality. Rasch analysis showed acceptable fit to the Rasch model, with items and people covering a broad measurement continuum and evidence of appropriate targeting of items to people, ordered thresholds, minimal differential item functioning by language, sex, or age. A summative score across items is defensible, yielding an interval score (0-50) where higher scores reflect worsening flare. The RA-FQ received endorsement from 88% of attendees that it passed the OMERACT Filter 2.0 "Eyeball Test" for instrument selection. CONCLUSION: The RA-FQ has been developed to identify and measure RA flares. Its review through OMERACT Filter 2.0 shows evidence of reliability, content and construct validity, and responsiveness. These properties merit its further validation as an outcome for clinical trials