Dissipationless Mergers of Elliptical Galaxies and the Evolution of the Fundamental Plane

We carry out numerical simulations of dissipationless major mergers of elliptical galaxies using initial galaxy models that consist of a dark matter halo and a stellar bulge with properties consistent with the observed fundamental plane. By varying the density profile of the dark matter halo (standard NFW versus adiabatically contracted NFW), the global stellar to dark matter mass ratio, and the orbit of the merging galaxies, we are able to assess the impact of each of these factors on the structure of the merger remnant. Our results indicate that the properties of the remnant bulge depend primarily on the angular momentum and energy of the orbit; for a cosmologically motivated orbit, the effective radius and velocity dispersion of the remnant bulge remain approximately on the fundamental plane. This indicates that the observed properties of elliptical galaxies are consistent with significant growth via late dissipationless mergers. We also find that the dark matter fraction within the effective radius of our remnants increases after the merger, consistent with the hypothesis that the tilt of the fundamental plane from the virial theorem is due to a varying dark matter fraction as a function of galaxy mass.Comment: 14 pages, 6 figures; MNRAS, in press. Minor revisions, results from an additional simulation adde

Dynamical Measurements of Black Hole Masses in Four Brightest Cluster Galaxies at 100 Mpc

We present stellar kinematics and orbit superposition models for the central regions of four Brightest Cluster Galaxies (BCGs), based upon integral-field spectroscopy at Gemini, Keck, and McDonald Observatories. Our integral-field data span radii from < 100 pc to tens of kpc. We report black hole masses, M_BH, of 2.1 +/- 1.6 x 10^10 M_Sun for NGC 4889, 9.7 + 3.0 - 2.6 x 10^9 M_Sun for NGC 3842, and 1.3 + 0.5 - 0.4 x 10^9 M_Sun for NGC 7768. For NGC 2832 we report an upper limit of M_BH < 9 x 10^9 M_Sun. Stellar orbits near the center of each galaxy are tangentially biased, on comparable spatial scales to the galaxies' photometric cores. We find possible photometric and kinematic evidence for an eccentric torus of stars in NGC 4889, with a radius of nearly 1 kpc. We compare our measurements of M_BH to the predicted black hole masses from various fits to the relations between M_BH and stellar velocity dispersion, luminosity, or stellar mass. The black holes in NGC 4889 and NGC 3842 are significantly more massive than all dispersion-based predictions and most luminosity-based predictions. The black hole in NGC 7768 is consistent with a broader range of predictions.Comment: 24 pages, 18 figures. Accepted for publication in Ap

N-terminal Pro B-type Natriuretic Peptide and the Evaluation of Cardiac Dysfunction and Severity of Disease in Cirrhotic Patients

Purpose: Cardiac dysfunction and hyperdynamic systemic circulation may be present in patients with cirrhosis. The purpose of this study was to identify relations between plasma levels of N-terminal-proBNP (NT-proBNP), reflecting early ventricular dysfunction, and the severity of liver disease and cardiac dysfunction in cirrhotic patients. Materials and Methods: Sixty-three cirrhotic patients and 15 controls (group 1) were enrolled in this study. Plasma levels of NT-proBNP were determined in echocardiographically examined patients, which were allocated to 1 of 3 groups according to Child-Pugh classification or into 2 groups, i.e., a compensated group without ascites (group 2) and decompensated group with ascites (group 3). Results: Plasma NT-proBNP levels were significantly higher in cirrhotic patients (groups 2 and 3) than in age-matched controls (155.9 and 198.3 vs. 40.3 pg/mL

Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

Background Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy. Methods We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance. Results We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography. Conclusion Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data

131I-metaiodobenzylguanidine (131I-MIBG) therapy for residual neuroblastoma: a mono-institutional experience with 43 patients

Incomplete response to therapy may compromise the outcome of children with advanced neuroblastoma. In an attempt to improve tumour response we incorporated 131I-metaiodobenzylguanidine (131I-MIBG) in the treatment regimens of selected stage 3 and stage 4 patients. Between 1986 and 1997, 43 neuroblastoma patients older than 1 year at diagnosis, 13 with stage 3 (group A) and 30 with stage 4 disease (group B) who had completed the first-line protocol without achieving complete response entered in this study. 131I-MIBG dose/course ranged from 2.5 to 5.5 Gbq (median, 3.7). The number of courses ranged from 1 to 5 (median 3) depending on the tumour response and toxicity. The most common acute side-effect was thrombocytopenia. Later side-effects included severe interstitial pneumonia in one patient, acute myeloid leukaemia in two, reduced thyroid reserve in 21. Complete response was documented in one stage 4 patient, partial response in 12 (two stage 3, 10 stage 4), mixed or no response in 25 (ten stage 3, 15 stage 4) and disease progression in five (one stage 3, four stage 4) Twenty-four patients (12/13 stage 3, 12/30 stage 4) are alive at 22–153 months (median, 59) from diagnosis. 131I-MIBG therapy may increase the cure rate of stage 3 and improve the response of stage 4 neuroblastoma patients with residual disease after first-line therapy. A larger number of patients should be treated to confirm these results but logistic problems hamper prospective and coordinated studies. Long-term toxicity can be severe. © 1999 Cancer Research Campaig

Gene expression level influences amino acid usage, but not codon usage, in the tsetse fly endosymbiont Wigglesworthia

Author Posting. © Society for General Mircobiology, 2003. This article is posted here by permission of Society for General Mircobiology for personal use, not for redistribution. The definitive version was published in Microbiology 149 (2003): 2585-2596, doi:10.1099/mic.0.26381-0.Wigglesworthia glossinidia brevipalpis, the obligate bacterial endosymbiont of the tsetse fly Glossina brevipalpis, is characterized by extreme genome reduction and AT nucleotide composition bias. Here, multivariate statistical analyses are used to test the hypothesis that mutational bias and genetic drift shape synonymous codon usage and amino acid usage of Wigglesworthia. The results show that synonymous codon usage patterns vary little across the genome and do not distinguish genes of putative high and low expression levels, thus indicating a lack of translational selection. Extreme AT composition bias across the genome also drives relative amino acid usage, but predicted high-expression genes (ribosomal proteins and chaperonins) use GC-rich amino acids more frequently than do low-expression genes. The levels and configuration of amino acid differences between Wigglesworthia and Escherichia coli were compared to test the hypothesis that the relatively GC-rich amino acid profiles of high-expression genes reflect greater amino acid conservation at these loci. This hypothesis is supported by reduced levels of protein divergence at predicted high-expression Wigglesworthia genes and similar configurations of amino acid changes across expression categories. Combined, the results suggest that codon and amino acid usage in the Wigglesworthia genome reflect a strong AT mutational bias and elevated levels of genetic drift, consistent with expected effects of an endosymbiotic lifestyle and repeated population bottlenecks. However, these impacts of mutation and drift are apparently attenuated by selection on amino acid composition at high-expression genes.This work was made possible by support to J. J. W. from the NIH (R01 GM62626-01) and NSF (DEB 0089455), and the Josephine Bay Paul and C. Michael Paul Foundation

Apolipoprotein epsilon 3 alleles are associated with indicators of neuronal resilience

<p>Abstract</p> <p>Background</p> <p>Epilepsy is associated with precocious development of Alzheimer-type neuropathological changes, including appearance of senile plaques, neuronal loss and glial activation. As inheritance of <it>APOE ε4 </it>allele(s) is reported to favor this outcome, we sought to investigate neuronal and glial responses that differ according to <it>APOE </it>genotype. With an eye toward defining ways in which <it>APOE ε3 </it>alleles may foster neuronal well-being in epilepsy and/or <it>APOE ε4 </it>alleles exacerbate neuronal decline, neuronal and glial characteristics were studied in temporal lobectomy specimens from epilepsy patients of either <it>APOE ε4,4 </it>or <it>APOE ε3,3 </it>genotype.</p> <p>Methods</p> <p>Tissue and/or cellular expressions of interleukin-1 alpha (IL-1α), apolipoprotein E (ApoE), amyloid β (Aβ) precursor protein (βAPP), synaptophysin, phosphorylated tau, and Aβ were determined in frozen and paraffin-embedded tissues from 52 <it>APOE ε3,3 </it>and 7 <it>APOE ε4,4 </it>(0.25 to 71 years) epilepsy patients, and 5 neurologically normal patients using Western blot, RT-PCR, and fluorescence immunohistochemistry.</p> <p>Results</p> <p>Tissue levels of IL-1α were elevated in patients of both <it>APOE ε3,3 </it>and <it>APOE ε4,4 </it>genotypes, and this elevation was apparent as an increase in the number of activated microglia per neuron (<it>APOE </it>ε<it>3,3 </it>vs <it>APOE ε4,4 </it>= 3.7 ± 1.2 vs 1.5 ± 0.4; <it>P </it>< 0.05). This, together with increases in βAPP and ApoE, was associated with apparent neuronal sparing in that <it>APOE ε4,4 </it>genotype was associated with smaller neuron size (<it>APOE ε4,4 </it>vs <it>APOE ε3,3 </it>= 173 ± 27 vs 356 ± 45; <it>P </it>≤ 0.01) and greater DNA damage (<it>APOE ε4,4 </it>vs <it>APOE ε3,3 </it>= 67 ± 10 vs 39 ± 2; <it>P </it>= 0.01). 3) Aβ plaques were noted at early ages in our epilepsy patients, regardless of <it>APOE </it>genotype (<it>APOE ε4,4 </it>age 10; <it>APOE ε3,3 </it>age 17).</p> <p>Conclusions</p> <p>Our findings of neuronal and glial events, which correlate with lesser neuronal DNA damage and larger, more robust neurons in epilepsy patients of <it>APOE ε3,3 </it>genotype compared to <it>APOE ε4,4 </it>genotype carriers, are consistent with the idea that the <it>APOE </it>ε<it>3,3 </it>genotype better protects neurons subjected to the hyperexcitability of epilepsy and thus confers less risk of AD (Alzheimer's disease).</p> <p>Please see related article: <url>http://www.biomedcentral.com/1741-7015/10/36</url></p

A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201