Generation and characterization of monoclonal antibodies that recognize human and murine supervillin protein isoforms

Supervillin isoforms have been implicated in cell proliferation, actin filament-based motile processes, vesicle trafficking, and signal transduction. However, an understanding of the roles of these proteins in cancer metastasis and physiological processes has been limited by the difficulty of obtaining specific antibodies against these highly conserved membrane-associated proteins. To facilitate research into the biological functions of supervillin, monoclonal antibodies were generated against the bacterially expressed human supervillin N-terminus. Two chimeric monoclonal antibodies with rabbit Fc domains (clones 1E2/CPTC-SVIL-1; 4A8/CPTC-SVIL-2) and two mouse monoclonal antibodies (clones 5A8/CPTC-SVIL-3; 5G3/CPTC-SVIL-4) were characterized with respect to their binding sites, affinities, and for efficacy in immunoblotting, immunoprecipitation, immunofluorescence microscopy and immunohistochemical staining. Two antibodies (1E2, 5G3) recognize a sequence found only in primate supervillins, whereas the other two antibodies (4A8, 5A8) are specific for a more broadly conserved conformational epitope(s). All antibodies function in immunoblotting, immunoprecipitation and in immunofluorescence microscopy under the fixation conditions identified here. We also show that the 5A8 antibody works on immunohistological sections. These antibodies should provide useful tools for the study of mammalian supervillins

Forming Young Bulges within Existing Disks: Statistical Evidence for External Drivers

Contrary to traditional models of galaxy formation, recent observations suggest that some bulges form within preexisting disk galaxies. Such late-epoch bulge formation within disks seems to be linked to disk gas inflow and central star formation, caused by either internal secular processes or galaxy mergers and interactions. We identify a population of galaxies likely to be experiencing active bulge growth within disks, using the criterion that the color within the half-light radius is bluer than the outer disk color. Such blue-centered galaxies make up >10% of star-forming disk galaxies within the Nearby Field Galaxy Survey, a broad survey designed to represent the natural diversity of the low-z galaxy population over a wide range of luminosities and environments. Blue-centered galaxies correlate at 99% confidence with morphological peculiarities suggestive of minor mergers and interactions. From this and other evidence, we argue that external drivers rather than internal secular processes probably account for the majority of blue-centered galaxies. We go on to discuss quantitative plausibility arguments indicating that blue-centered evolutionary phases may represent an important mode of bulge growth for most disk galaxies, leading to significant changes in bulge-to-disk ratio without destroying disks. If this view is correct, bulge growth within disks may be a natural consequence of the repeated galaxy mergers and interactions inherent in hierarchical galaxy formation.Comment: 18 pages including 12 figures, AJ, accepte

Intercalative Stacking: A Critical Feature of DNA Charge-Transport Electrochemistry

In electrochemistry experiments on DNA-modified electrodes, features of the redox probe that determine efficient charge transport through DNA-modified surfaces have been explored using methylene blue (MB^+) and Ru(NH_3)_6^(3+) as DNA-binding redox probes. The electrochemistry of these molecules is studied as a function of ionic strength to determine the necessity of tight binding to DNA and the number of electrons involved in the redox reaction; on the DNA surface, MB^+ displays 2e^-/1H^+ electrochemistry (pH 7) and Ru(NH^3)_6^(3+) displays 1e^- electrochemistry. We examine also the effect of electrode surface passivation and the effect of the mode (intercalation or electrostatic) of MB^+ and Ru(NH_3)_6^(3+) binding to DNA to highlight the importance of intercalation for reduction by a DNA-mediated charge-transport pathway. Furthermore, in experiments in which MB^+ is covalently linked to the DNA through a σ-bonded tether and the ionic strength is varied, it is demonstrated that intercalative stacking rather than covalent σ-bonding is essential for efficient reduction of MB^+. The results presented here therefore establish that efficient charge transport to the DNA-binding moiety in DNA films requires intercalative stacking and is mediated by the DNA base pair array

Preventing Pneumonia Through Early Mobilization of Critically Ill Adults

The purpose of this critically appraised topic (CAT) is to investigate early mobilization and its effect on preventing pneumonia in adults in the intensive care unit (ICU). The final portfolio contains four research articles from both national and international journals. Study designs included two meta-analyses, one case series, and one retrospective study. All four of the articles specifically described the effects of early mobilization on individuals in the hospital and ICU and showed positive results in reducing the likelihood of developing pneumonia. This CAT will be used to draft new practice guidelines for mentoring new managers in both occupational therapy and physical therapy

Close Galaxy Counts as a Probe of Hierarchical Structure Formation

Standard LCDM predicts that the major merger rate of galaxy-size dark matter halos rises rapidly with redshift. The average number of close companions per galaxy, Nc, is often used to infer the galaxy merger rate, however, recent observational studies suggest that Nc evolves very little with redshift. Here we use a "hybrid" N- body simulation plus analytic substructure model to predict Nc directly. We identify dark matter subhalos with galaxies and show that the observed lack of close pair count evolution arises because the high merger rate per halo at early times is counteracted by a decrease in the number of halos massive enough to host a galaxy pair. We compare our results to data compiled from the DEEP2, SSRS2, and the UZC redshift surveys. Observed pair counts match our predictions if we assume a monotonic mapping between galaxy luminosity and the maximum circular velocity that each subhalo had when it was first accreted onto its host halo. This suggests that satellite galaxies are significantly more resilient to destruction than are dissipationless dark matter subhalos. We argue that while Nc does not provide a direct measure of the halo merger rate, it offers a powerful means to constrain the Halo Occupation Distribution and the spatial distribution of galaxies within halos. Interpreted in this way, close pair counts provide a useful test of galaxy formation processes on < 100 kpc scales.Comment: 16 pages, 16 figures, minor change to figure 10, figure captions updated, typos corrected, Figure 4 corrected, version accepted for publication by Ap

Pair-instability and super-luminous supernova discoveries at z = 2.05, z = 2.50, and z = 3.90

We present the discovery of three super-luminous supernovae (SLSNe) at z = 2 - 4 as part of our survey to detect ultraviolet-luminous supernova at z > 2. SLSNe are ≥10 times more luminous than normal supernova types, reaching peak luminosities of ≳10^(44) erg s^(−1). A small subset of SLSNe (type SLSN-R) exhibit a slow evolution, and thus enormous integrated energies (≳10^(51) erg), consistent with the radiative decay of several solar masses of 56 Ni. SLSN-R are believed to be the deaths of very massive stars, ∼140 - 260 M_⊙, that are theorized to result in pair-instability supernovae. Two of the high redshift SLSNe presented here are consistent with the behavior of SLSN-R out to the extent in which their light curves are sampled, with the third event being consistent with the more rapid fade of the type II-L SLSN SN 2008es at z = 0.205. SLSNe are extremely rare locally but are expected to have been more common in the early Universe and as members of the first generation of stars to form after the Big Bang, the Population III stars. The high intrinsic luminosity of SLSNe and their detectability using our image-stacking technique out to z ∼ 6 provide the first viable route to detect and study the deaths of massive Population III stars which are expected to form in pristine gas at redshifts as low as z ∼ 2

The Tully-Fisher Relation as a Measure of Luminosity Evolution: A Low Redshift Baseline for Evolving Galaxies

We use optical rotation curves to investigate the R-band Tully-Fisher properties of a sample of 90 spiral galaxies in close pairs. The galaxies follow the Tully-Fisher relation remarkably well, with the exception of eight distinct 3-sigma outliers. Although most of the outliers show signs of recent star formation, gasdynamical effects are probably the dominant cause of their anomalous Tully-Fisher properties. Four outliers with small emission line widths have very centrally concentrated line emission and truncated rotation curves; the central emission indicates recent gas infall after a close galaxy-galaxy pass. These four galaxies may be local counterparts to compact, blue galaxies at intermediate redshift. The remaining galaxies have a negligible offset from the reference Tully-Fisher relation, but a shallower slope (2.6-sigma significance) and a 25% larger scatter. We characterize the non-outlier sample with measures of distortion and star formation to search for third parameter dependence in the residuals of the TF relation. Severe kinematic distortion is the only significant predictor of TF residuals; this distortion is not, however, responsible for the slope difference from the reference distribution. Because the outliers are easily removed by sigma clipping, we conclude that even in the presence of some tidal distortion, detection of moderate luminosity evolution should be possible with high-redshift samples the size of this 90-galaxy study. (Abridged.)Comment: LaTeX document, 55 pages including 18 figures, to appear in A

Evaluation of the rheumatoid arthritis susceptibility loci HLA-DRB1, PTPN22, OLIG3/TNFAIP3, STAT4 and TRAF1/C5 in an inception cohort.

INTRODUCTION: This study investigated five confirmed rheumatoid arthritis (RA) susceptibility genes/loci (HLA-DRB1, PTPN22, STAT4, OLIG3/TNFAIP3 and TRAF1/C5) for association with susceptibility and severity in an inception cohort. METHODS: The magnitude of association for each genotype was assessed in 1,046 RA subjects from the Yorkshire Early RA cohort and in 5,968 healthy UK controls. Additional exploratory subanalyses were undertaken in subgroups defined by autoantibody status (rheumatoid factor and anti-cyclic citrullinated peptide) or disease severity (baseline articular erosions, Health Assessment Questionnaire (HAQ) score and swollen joint count (SJC)). RESULTS: In the total RA inception cohort, the HLA-DRB1 shared epitope (per-allele odds ratio (OR) = 2.1, trend P < 0.0001), PTPN22 (per-allele OR = 1.5, trend P < 0.0001), OLIG3/TNFAIP3 locus (per-allele OR = 1.2, trend P = 0.009) and TRAF1/C5 locus (per-allele OR = 1.1, trend P = 0.04) were associated with RA. The magnitude of association for these loci was increased in those patients who were autoantibody-positive. PTPN22 was associated with autoantibody-negative RA (per-allele OR = 1.3, trend P = 0.04). There was no evidence of association between these five genetic loci and baseline erosions or SJC in the total RA cohort, after adjustment for symptom duration. TRAF1/C5 was significantly associated with baseline HAQ, however, following adjustment for symptom duration (P trend = 0.03). CONCLUSIONS: These findings support the mounting evidence that different genetic loci are associated with autoantibody-positive and autoantibody-negative RA, possibly suggesting that many of the genes identified to date are associated with autoantibody production. Additional studies with a specific focus on autoantibody-negative RA will be needed to identify the genes predisposing to this RA subgroup. The TRAF1/C5 locus in particular warrants further investigation in RA as a potential disease severity locus

Simulation-based power and sample size calculation for designing interrupted time series analyses of count outcomes in evaluation of health policy interventions

Objective: The purpose of this study was to present the design, model, and data analysis of an interrupted time series (ITS) model applied to evaluate the impact of health policy, systems, or environmental interventions using count outcomes. Simulation methods were used to conduct power and sample size calculations for these studies. Methods: We proposed the models and analyses of ITS designs for count outcomes using the Strengthening Translational Research in Diverse Enrollment (STRIDE) study as an example. The models we used were observation-driven models, which bundle a lagged term on the conditional mean of the outcome for a time series of count outcomes. Results: A simulation-based approach with ready-to-use computer programs was developed to calculate the sample size and power of two types of ITS models, Poisson and negative binomial, for count outcomes. Simulations were conducted to estimate the power of segmented autoregressive (AR) error models when autocorrelation ranged from -0.9 to 0.9, with various effect sizes. The power to detect the same magnitude of parameters varied largely, depending on the testing level change, the trend change, or both. The relationships between power and sample size and the values of the parameters were different between the two models. Conclusion: This article provides a convenient tool to allow investigators to generate sample sizes that will ensure sufficient statistical power when the ITS study design of count outcomes is implemented