Use of fluorescent immunohistochemistry to investigate NF-κB involvement in brain pathologies

2013 Fall.Includes bibliographical references.Nuclear Factor Kappa Beta (NF-κB) is a transcription factor ubiquitously expressed in mammalian cells and involved in a broad spectrum of physiological responses. In the central nervous system (CNS), NF-κB is responsible for the regulation of several brain-specific processes, ranging from synaptic plasticity to neuroinflammation (Mattson and Camandola, 2001). The effects of NF-κB activation are highly variable and the transcription factor appears to play a dichotomous role in brain pathologies. Parkinson's Disease (PD) is the second most prevalent neurodegenerative disease in the world and is characterized by the progressive, irreversible loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Neuroinflammation, a CNS-specific immune response facilitated by glial cells, is now know to be an important contributing factor to PD pathology. Many neuroinflammatory responses have been linked to glial NF-κB activation, although the mechanisms have not yet been established. Drug-induced seizures are a serious adverse drug reaction (ADR) associated with both CNS- and non-CNS-targeting drugs. The current methods of drug safety evaluation rely solely on behavioral analysis and therefore often fail to identify potentially seizurogenic activity. Studies have suggested that neuronal NF-κB activation may be an early stress response and serve a neuroprotective function. The molecular mechanisms involved in seizurogenesis are also largely unknown. To study the role of NF-κB in these models of CNS injury, I employed fluorescent immunohistochemical (IHC) staining, a molecular technique that utilizes antibody-antigen binding to identify and visualize specific proteins in tissue. IHC has a wide range of applications and is often used for both laboratory research and clinical diagnostics. The following studies examined the role of NF-κB in CNS injury by using fluorescent IHC staining to characterize a transgenic mouse containing a NF-κB-driven enhanced green fluorescent protein (cis-NF-κBeGFP) construct in order to detect cell-specific changes in NF-κB activity. Using this method in the MPTP neurotoxin-induced model of Parkinson's Disease, I found that NF-κB-mediated glial activation accompanied loss of dopaminergic neurons and that treatment with novel pharmacological inhibitors of NF-κB attenuated this response. In the kainic acid (KA) model of drug-induced seizures, this method showed that neuronal activation of NF-κB occurs at sub-seizurogenic doses and may be an early, neuroprotective stress response. Fluorescent IHC staining in models of neuropathologies is useful for mechanistic research, but may also be an effective tool in drug-development. Use of fluorescent IHC with the NF-κB transgenic mouse allows for characterization of NF-κB signaling, as it relates to other proteins in vivo. Further optimization of this method could be extremely advantageous to NF-κB research

Feasibility and Acceptability of Methods to Collect Follow-Up Information From Parents 12 Months After Their Child's Emergency Admission to Pediatric Intensive Care.

OBJECTIVES: To evaluate the feasibility and acceptability of different methods of collecting follow-up data from parents 12 months after their child's emergency admission to a PICU. DESIGN: Mixed-methods explanatory sequential design. SETTING: One regional PICU transport service and three PICUs in England. PATIENTS: Children undergoing emergency transport to PICU recruited to an ongoing biomarker study whose parents consented to be contacted for follow-up 12 months after PICU admission. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Parents or guardians who consented were asked to complete three questionnaires about their child's functional status, quality of life, and behavior 12 months after PICU admission. Parents were given a choice about method of questionnaire completion: postal, online, or telephone interview and also asked for telephone feedback about the process and the reasons for their choice. Of 486 parents who consented to be contacted at 12 months, 232 were successfully contacted. Consent to receive questionnaires was obtained in 218 of 232 (94%). Of the 218 parents, 102 (47%) chose to complete questionnaires online (with 77% completion rate), 91 (42%) chose to complete postal questionnaires (48% completion rate), and 25 (11%) chose to complete questionnaires by telephone interview (44% completion rate). CONCLUSIONS: Parents expressed different preferences for follow-up questionnaire completion. Response rates varied by completion method. Understanding and catering for parental preferences is an important factor in maximizing response rates for follow-up studies in intensive care

Systematic errors in weak lensing: application to SDSS galaxy-galaxy weak lensing

Weak lensing is emerging as a powerful observational tool to constrain cosmological models, but is at present limited by an incomplete understanding of many sources of systematic error. Many of these errors are multiplicative and depend on the population of background galaxies. We show how the commonly cited geometric test, which is rather insensitive to cosmology, can be used as a ratio test of systematics in the lensing signal at the 1 per cent level. We apply this test to the galaxy-galaxy lensing analysis of the Sloan Digital Sky Survey (SDSS), which at present is the sample with the highest weak lensing signal to noise and has the additional advantage of spectroscopic redshifts for lenses. This allows one to perform meaningful geometric tests of systematics for different subsamples of galaxies at different mean redshifts, such as brighter galaxies, fainter galaxies and high-redshift luminous red galaxies, both with and without photometric redshift estimates. We use overlapping objects between SDSS and the DEEP2 and 2SLAQ spectroscopic surveys to establish accurate calibration of photometric redshifts and to determine the redshift distributions for SDSS. We use these redshift results to compute the projected surface density contrast DeltaSigma around 259 609 spectroscopic galaxies in the SDSS; by measuring DeltaSigma with different source samples we establish consistency of the results at the 10 per cent level (1-sigma). We also use the ratio test to constrain shear calibration biases and other systematics in the SDSS survey data to determine the overall galaxy-galaxy weak lensing signal calibration uncertainty. We find no evidence of any inconsistency among many subsamples of the data.Comment: 39 pages, 19 figure

Prenatal Exposure of the Ovine Fetus to Androgens Sexually Differentiates the Steroid Feedback Mechanisms That Control Gonadotropin Releasing Hormone Secretion and Disrupts Ovarian Cycles

Exposure of the female sheep fetus to exogenous testosterone in early pregnancy permanently masculinizes the reproductive neuroendocrine axis. Specifically, in utero androgens given to female lambs from day 30 to 90 of a 147 day pregnancy dramatically altered the response of the gonadotropin releasing hormone (GnRH) neuronal network in the hypothalamus to both estrogen (E) and progesterone (P) feedback. Elevated concentrations of estrogen stimulated a massive release of GnRH in gonadectomized female sheep; however, male and androgenized female lambs were unable to respond to high E concentrations by producing this preovulatory-like “surge” of GnRH. Further, the inhibitory actions of progesterone (P) were also sexually differentiated and adult males and androgenized females were much less responsive to P-negative feedback than normal ewes. The consequences of these abnormal steroid feedback mechanisms were reflected in the fact that only 72% of ovary-intact androgenized ewes exhibited normal estrous cycles in their first breeding season whereas none had a single estrous cycle during the second breeding season. In contrast, 100% of the control animals exhibited repeated reproductive cycles in both seasons. These data indicate that a relatively short exposure to male hormones during in utero life permanently alters the neural mechanisms that control reproduction and leads progressively to a state of infertility.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44102/1/10508_2004_Article_365183.pd

Photometric Redshift Probability Distributions for Galaxies in the SDSS DR8

We present redshift probability distributions for galaxies in the SDSS DR8 imaging data. We used the nearest-neighbor weighting algorithm presented in Lima et al. 2008 and Cunha et al. 2009 to derive the ensemble redshift distribution N(z), and individual redshift probability distributions P(z) for galaxies with r < 21.8. As part of this technique, we calculated weights for a set of training galaxies with known redshifts such that their density distribution in five dimensional color-magnitude space was proportional to that of the photometry-only sample, producing a nearly fair sample in that space. We then estimated the ensemble N(z) of the photometric sample by constructing a weighted histogram of the training set redshifts. We derived P(z) s for individual objects using the same technique, but limiting to training set objects from the local color-magnitude space around each photometric object. Using the P(z) for each galaxy, rather than an ensemble N(z), can reduce the statistical error in measurements that depend on the redshifts of individual galaxies. The spectroscopic training sample is substantially larger than that used for the DR7 release, and the newly added PRIMUS catalog is now the most important training set used in this analysis by a wide margin. We expect the primary source of error in the N(z) reconstruction is sample variance: the training sets are drawn from relatively small volumes of space. Using simulations we estimated the uncertainty in N(z) at a given redshift is 10-15%. The uncertainty on calculations incorporating N(z) or P(z) depends on how they are used; we discuss the case of weak lensing measurements. The P(z) catalog is publicly available from the SDSS website.Comment: 29 pages, 9 figures, single colum

Galaxy-galaxy Lensing: Dissipationless Simulations Versus the Halo Model

Galaxy-galaxy lensing is a powerful probe of the relation between galaxies and dark matter halos, but its theoretical interpretation requires a careful modeling of various contributions, such as the contribution from central and satellite galaxies. For this purpose, a phenomenological approach based on the halo model has been developed, allowing for fast exploration of the parameter space of models. In this paper, we investigate the ability of the halo model to extract information from the g-g weak lensing signal by comparing it to high-resolution dissipationless simulations that resolve subhalos. We find that the halo model reliably determines parameters such as the host halo mass of central galaxies, the fraction of galaxies that are satellites, and their radial distribution inside larger halos. If there is a significant scatter present in the central galaxy host halo mass distribution, then the mean and median mass of that distribution can differ significantly from one another, and the halo model mass determination lies between the two. This result suggests that when analyzing the data, galaxy subsamples with a narrow central galaxy halo mass distribution, such as those based on stellar mass, should be chosen for a simpler interpretation of the results.Comment: 13 pages, 6 figures; minor changes made, matches MNRAS accepted versio

SDSS galaxy bias from halo mass-bias relation and its cosmological implications

We combine the measurements of luminosity dependence of bias with the luminosity dependent weak lensing analysis of dark matter around galaxies to derive the galaxy bias and constrain nonlinear mass and cosmological parameters. We take advantage of theoretical and simulation predictions that predict that while halo bias is rapidly increasing with mass for high masses, it is nearly constant in low mass halos. We use a new weak lensing analysis around the same SDSS galaxies to determine their halo mass probability distribution. These halo mass probability distributions are used to predict the bias for each luminosity subsample and we find an excellent agreement with observed values. The required nonlinear mass suggests slightly lower matter density than usually assumed, Omegam=0.25+/- 0.03 for the simplest models. We combine the bias constraints with those from the WMAP and the SDSS power spectrum analysis to derive new constraints on bias and sigma_8. For the most general parameter space we find sigma_8=0.88+/- 0.06 and b_*=0.99+/- 0.07. In the context of spatially flat models we improve the limit on the neutrino mass for the case of 3 degenerate families from m_nu<0.6eV without bias to m_nu<0.18eV with bias (95% c.l.), which is weakened to m_nu<0.24eV if running is allowed. The corresponding limit for 3 massless + 1 massive neutrino is 1.37eV.Comment: 19 pages, 7 figures, accepted in PR

Semi-Analytic Modelling of Galaxy Formation: The Local Universe

Using semi-analytic models of galaxy formation, we investigate galaxy properties such as the Tully-Fisher relation, the B and K-band luminosity functions, cold gas contents, sizes, metallicities, and colours, and compare our results with observations of local galaxies. We investigate several different recipes for star formation and supernova feedback, including choices that are similar to the treatment in Kauffmann, White & Guiderdoni (1993) and Cole et al. (1994) as well as some new recipes. We obtain good agreement with all of the key local observations mentioned above. In particular, in our best models, we simultaneously produce good agreement with both the observed B and K-band luminosity functions and the I-band Tully-Fisher relation. Improved cooling and supernova feedback modelling, inclusion of dust extinction, and an improved Press-Schechter model all contribute to this success. We present results for several variants of the CDM family of cosmologies, and find that models with values of $\Omega_0 \simeq 0.3$--0.5 give the best agreement with observations.Comment: 26 pages, LaTeX, MNRAS format, 23 inlined postscript figures. Accepted for publication in MNRAS. Revised version contains substantial changes including improved models. High resolution figures, original version, and summary of changes may be found at http://www.fiz.huji.ac.il/~rachels/papers/sp.htm

Protocol for a Randomized Multiple Center Trial of Conservative Versus Liberal Oxygenation Targets in Critically Ill Children (Oxy-PICU): Oxygen in Paediatric Intensive Care

OBJECTIVES: Oxygen administration is a fundamental part of pediatric critical care, with supplemental oxygen offered to nearly every acutely unwell child. However, optimal targets for systemic oxygenation are unknown. Oxy-PICU aims to evaluate the clinical effectiveness and cost-effectiveness of a conservative peripheral oxygen saturation (Spo2) target of 88-92% compared with a liberal target of more than 94%. DESIGN: Pragmatic, open, multiple-center, parallel group randomized control trial with integrated economic evaluation. SETTING: Fifteen PICUs across England, Wales, and Scotland. PATIENTS: Infants and children age more than 38 week-corrected gestational age to 16 years who are accepted to a participating PICU as an unplanned admission and receiving invasive mechanical ventilation with supplemental oxygen for abnormal gas exchange. INTERVENTION: Adjustment of ventilation and inspired oxygen settings to achieve an Spo2 target of 88-92% during invasive mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Randomization is 1:1 to a liberal Spo2 target of more than 94% or a conservative Spo2 target of 88-92% (inclusive), using minimization with a random component. Minimization will be performed on: age, site, primary reason for admission, and severity of abnormality of gas exchange. Due to the emergency nature of the treatment, approaching patients for written informed consent will be deferred to after randomization. The primary clinical outcome is a composite of death and days of organ support at 30 days. Baseline demographics and clinical status will be recorded as well as daily measures of oxygenation and organ support, and discharge outcomes. This trial received Health Research Authority approval on December 23, 2019 (reference: 272768), including a favorable ethical opinion from the East of England-Cambridge South Research Ethics Committee (reference number: 19/EE/0362). Trial findings will be disseminated in national and international conferences and peer-reviewed journals

The WiggleZ Dark Energy Survey: Direct constraints on blue galaxy intrinsic alignments at intermediate redshifts

Correlations between the intrinsic shapes of galaxy pairs, and between the intrinsic shapes of galaxies and the large-scale density field, may be induced by tidal fields. These correlations, which have been detected at low redshifts (z<0.35) for bright red galaxies in the Sloan Digital Sky Survey (SDSS), and for which upper limits exist for blue galaxies at z~0.1, provide a window into galaxy formation and evolution, and are also an important contaminant for current and future weak lensing surveys. Measurements of these alignments at intermediate redshifts (z~0.6) that are more relevant for cosmic shear observations are very important for understanding the origin and redshift evolution of these alignments, and for minimising their impact on weak lensing measurements. We present the first such intermediate-redshift measurement for blue galaxies, using galaxy shape measurements from SDSS and spectroscopic redshifts from the WiggleZ Dark Energy Survey. Our null detection allows us to place upper limits on the contamination of weak lensing measurements by blue galaxy intrinsic alignments that, for the first time, do not require significant model-dependent extrapolation from the z~0.1 SDSS observations. Also, combining the SDSS and WiggleZ constraints gives us a long redshift baseline with which to constrain intrinsic alignment models and contamination of the cosmic shear power spectrum. Assuming that the alignments can be explained by linear alignment with the smoothed local density field, we find that a measurement of \sigma_8 in a blue-galaxy dominated, CFHTLS-like survey would be contaminated by at most +/-0.02 (95% confidence level, SDSS and WiggleZ) or +/-0.03 (WiggleZ alone) due to intrinsic alignments. [Abridged]Comment: 18 pages, 12 figures, accepted to MNRAS; v2 has correction to one author's name, NO other changes; v3 has minor changes in explanation and calculations, no significant difference in results or conclusions; v4 has an additional footnote about model interpretation, no changes to data/calculations/result