A High Throughput MHC II Binding Assay for Quantitative Analysis of Peptide Epitopes

Biochemical assays with recombinant human MHC II molecules can provide rapid, quantitative insights into immunogenic epitope identification, deletion, or design1,2. Here, a peptide-MHC II binding assay is scaled to 384-well format. The scaled down protocol reduces reagent costs by 75% and is higher throughput than previously described 96-well protocols1,3-5. Specifically, the experimental design permits robust and reproducible analysis of up to 15 peptides against one MHC II allele per 384-well ELISA plate. Using a single liquid handling robot, this method allows one researcher to analyze approximately ninety test peptides in triplicate over a range of eight concentrations and four MHC II allele types in less than 48 hr. Others working in the fields of protein deimmunization or vaccine design and development may find the protocol to be useful in facilitating their own work. In particular, the step-by-step instructions and the visual format of JoVE should allow other users to quickly and easily establish this methodology in their own labs

A matrix solution to pentagon equation with anticommuting variables

We construct a solution to pentagon equation with anticommuting variables living on two-dimensional faces of tetrahedra. In this solution, matrix coordinates are ascribed to tetrahedron vertices. As matrix multiplication is noncommutative, this provides a "more quantum" topological field theory than in our previous works

Objectively Measured Adherence to Physical Activity Guidelines After Acute Coronary Syndrome

Physical activity is a cornerstone of secondary prevention after acute coronary syndromes (ACS). Guidelines strongly recommend that post-ACS patients achieve ≥30 min of moderate aerobic activity such as brisk walking on at least 5 days per week within 2 weeks of discharge (1). Yet, little is known about the extent to which post-ACS patients are meeting physical activity guidelines. Prior studies assessing physical activity after ACS were limited by reliance on self-reports (2). The purpose of this study was to use an objective measure of physical activity to describe the proportion of ACS patients following physical activity recommendations in the high-risk post-discharge period. Between 2009 and 2012, we enrolled patients hospitalized for myocardial infarction (MI) or unstable angina into the PULSE (Prescription Use, Lifestyle, and Stress Evaluation) study. Some patients participated in an ancillary study in which they were provided with an Actical accelerometer (Philips Respironics, Bend, Oregon) at or soon after discharge (3). Patients were asked to continuously wear the device on their nondominant wrist and to return the device 1 month later. All patients provided informed consent. The institutional review board of Columbia University Medical Center approved the study

The cellular magnetic response and biocompatibility of biogenic zinc- and cobalt-doped magnetite nanoparticles.

The magnetic moment and anisotropy of magnetite nanoparticles can be optimised by doping with transition metal cations, enabling their properties to be tuned for different biomedical applications. In this study, we assessed the suitability of bacterially synthesized zinc- and cobalt-doped magnetite nanoparticles for biomedical applications. To do this we measured cellular viability and activity in primary human bone marrow-derived mesenchymal stem cells and human osteosarcoma-derived cells. Using AC susceptibility we studied doping induced changes in the magnetic response of the nanoparticles both as stable aqueous suspensions and when associated with cells. Our findings show that the magnetic response of the particles was altered after cellular interaction with a reduction in their mobility. In particular, the strongest AC susceptibility signal measured in vitro was from cells containing high-moment zinc-doped particles, whilst no signal was observed in cells containing the high-anisotropy cobalt-doped particles. For both particle types we found that the moderate dopant levels required for optimum magnetic properties did not alter their cytotoxicity or affect osteogenic differentiation of the stem cells. Thus, despite the known cytotoxicity of cobalt and zinc ions, these results suggest that iron oxide nanoparticles can be doped to sufficiently tailor their magnetic properties without compromising cellular biocompatibility

Depression and Doctor-Patient Communication in the Emergency Department

OBJECTIVE: Depression may adversely affect health outcomes by influencing doctor-patient communication. We aimed to determine the association between depressive symptoms and doctor-patient communication among patients presenting to the emergency department (ED) with a suspected acute coronary syndrome (ACS). METHOD: We enrolled a consecutive sample of 500 patients evaluated for ACS symptoms from the ED of an urban medical center. Depressive symptoms (8-item Patient Health Questionnaire, PHQ-8) and doctor-patient communication in the ED (Interpersonal Processes of Care) were assessed during hospitalization. Logistic regression was used to determine the association between depressive symptoms and doctor-patient communication, adjusting for age, sex, race, ethnicity, education, language, health insurance status and comorbidities. RESULTS: Compared to nondepressed patients, depressed patients (PHQ-8≥10) were more likely (P<.05) to report suboptimal communication on five of seven communication domains: clarity, elicitation of concerns, explanations, patient-centered decision making and discrimination. A greater proportion of depressed versus nondepressed patients reported suboptimal overall communication (39.8% versus 22.9%, P<.001). In adjusted analyses, depressed patients remained more likely to report suboptimal doctor-patient communication (adjusted odds ratio 2.42, 95% confidence interval 1.52-3.87; P<.001). CONCLUSIONS: Depressed patients with ACS symptoms reported less optimal doctor-patient communication in the ED than nondepressed patients. Research is needed to determine whether subjectively rated differences in communication are accompanied by observable differences

Dielectric function of InGaAs in the visible

Measurements are reported of the dielectric function of thermodynamically stable In(x)Ga(1-x)As in the composition range 0.3 equal to or less than X = to or less than 0.7. The optically thick samples of InGaAs were made by molecular beam epitaxy (MBE) in the range 0.4 = to or less than X = to or less than 0.7 and by metal-organic chemical vapor deposition (MOCVD) for X = 0.3. The MBE made samples, usually 1 micron thick, were grown on semi-insulating InP and included a strain release structure. The MOCVD sample was grown on GaAs and was 2 microns thick. The dielectric functions were measured by variable angle spectroscopic ellipsometry in the range 1.55 to 4.4 eV. The data was analyzed assuming an optically thick InGaAs material with an oxide layer on top. The thickness of this layer was estimated by comparing the results for the InP lattice matched material, i.e., X = 0.53, with results published in the literature. The top oxide layer mathematically for X = 0.3 and X = 0.53 was removed to get the dielectric function of the bare InGaAs. In addition, the dielectric function of GaAs in vacuum, after a protective arsenic layer was removed. The dielectric functions for X = 0, 0.3, and 0.53 together with the X = 1 result from the literature to evaluate an algorithm for calculating the dielectric function of InGaAs for an arbitrary value of X(0 = to or less than X = to or less than 1) were used. Results of the dielectric function calculated using the algorithm were compared with experimental data

Cloud Condensation Nuclei properties of model and atmospheric HULIS

Humic like substances (HULIS) have been identified as a major fraction of the organic component of atmospheric aerosols. These large multifunctional compounds of both primary and secondary sources are surface active and water soluble. Hence, it is expected that they could affect activation of organic aerosols into cloud droplets. We have compared the activation of aerosols containing atmospheric HULIS extracted from fresh, aged and pollution particles to activation of size fractionated fulvic acid from an aquatic source (Suwannee River Fulvic Acid), and correlated it to the estimated molecular weight and measured surface tension. A correlation was found between CCN-activation diameter of SRFA fractions and number average molecular weight of the fraction. The lower molecular weight fractions activated at lower critical diameters, which is explained by the greater number of solute species in the droplet with decreasing molecular weight. The three aerosol-extracted HULIS samples activated at lower diameters than any of the size-fractionated or bulk SRFA. The Köhler model was found to account for activation diameters, provided that accurate physico-chemical parameters are known