The Quiescent Intracluster Medium in the Core of the Perseus Cluster

Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July

Oxidative Stress and Modification of Renal Vascular Permeability Are Associated with Acute Kidney Injury during P. berghei ANKA Infection

Malaria associated-acute kidney injury (AKI) is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. However, the causes that lead to a framework of malaria-associated AKI are still poorly characterized. Some clinical studies speculate that oxidative stress products, a characteristic of Plasmodium infection, as well as proinflammatory response induced by the parasite are involved in its pathophysiology. Therefore, we aimed to investigate the development of malaria-associated AKI during infection by P. berghei ANKA, with special attention to the role played by the inflammatory response and the involvement of oxidative stress. For that, we took advantage of an experimental model of severe malaria that showed significant changes in the renal pathophysiology to investigate the role of malaria infection in the renal microvascular permeability and tissue injury. Therefore, BALB/c mice were infected with P. berghei ANKA. To assess renal function, creatinine, blood urea nitrogen, and ratio of proteinuria and creatininuria were evaluated. The products of oxidative stress, as well as cytokine profile were quantified in plasma and renal tissue. The change of renal microvascular permeability, tissue hypoxia and cellular apoptosis were also evaluated. Parasite infection resulted in renal dysfunction. Furthermore, we observed increased expression of adhesion molecule, proinflammatory cytokines and products of oxidative stress, associated with a decrease mRNA expression of HO-1 in kidney tissue of infected mice. The measurement of lipoprotein oxidizability also showed a significant increase in plasma of infected animals. Together, our findings support the idea that products of oxidative stress, as well as the immune response against the parasite are crucial to changes in kidney architecture and microvascular endothelial permeability of BALB/c mice infected with P. berghei ANKA.State of Sao Paulo Foundation for Research Support (FAPESP)State of Sao Paulo Foundation for Research Support (FAPESP) [07/07139-3, 10/52180-4, 12/02270-2]CAPESCAPESBrazilian Council of Scientific and Technologic Development (International Associated Laboratory of Renal Immunopathology, CNPq/Inserm)Brazilian Council of Scientific and Technologic Development (International Associated Laboratory of Renal Immunopathology, CNPq/Inserm)Complex Fluids INCT (FAPESP/CNPq)Complex Fluids INCT (FAPESP/CNPq

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

Analysis of sequestration of infected red blood cell in renal tissue.

<p>(A) Representative figure of presence of malaria pigment hemozoin in renal tissue sections visualized by hematoxylin and eosin, or under polarized light. Detection of hemozoin at glomeruli (<b>i</b>) and vascular endothelium (<b>ii</b>). (B) Hemozoin quantification in histological section of renal tissue. (C) <i>P. berghei</i> ANKA mRNA quantified by qPCR in renal tissue of BALB/c infected mice. Each graph represents the mean of 5–10 animals per group ± standard deviation. One-way ANOVA with Bonferroni post-test was performed using GraphPad Prism. *** p<0.001 vs. the control group – day 0, # p<0.01 vs. day 12.</p

<i>Ex vivo</i> adherence of <i>P. berghei</i> ANKA^GFP iRBC to renal tissue.

<p>(<b>A</b>) Representative microscopic image of the <i>ex vivo</i> adherence assays showing iRBC adhering to renal tissue sections from control (right) and infected (left) mice (200X magnification). (<b>B</b>) Adhesion of iRBC treated or not with proteinase K prior incubation with the frozen kidney sections. All data represent the number of bound iRBC per area. (mean±s.e.m). Two-way ANOVA with Bonferroni post-test was performed using GraphPad Prism. *P<0.05; **P<0.01. (n.d.: not-detected).</p

Evaluation of hypoxia, HIF-1α in renal tissue and apoptosis during malaria-associated AKI.

<p>(A) Representative immunohistochemistry, and (B) quantification of renal hypoxia in control and <i>P. berghei</i> ANKA infected mice. (C) mRNA expression of HIF-1α in renal tissue. (D) Evaluation of apoptosis in kidney section of control and <i>P. berghei</i> ANKA infected mice. Each graph represents the mean of 5–10 animals per group ± standard deviation. One-way ANOVA with Bonferroni post-test was performed using GraphPad Prism. * P<0.05 vs control group – day 0, ** p<0.01 vs control group – day 0.</p

Impairment of renal function during <i>P. berghei</i> ANKA malaria infection.

<p>(A) Parasitemia, and (B) survival of BALB/c mice infected with 10⁶ parasitized erythrocytes by <i>P. berghei</i> ANKA. Renal function was assessed by (C) plasma creatinine, (D) blood urea nitrogen (BUN) and (E) quantification of erythrocyte protoporphyrin estimated on different days after infection. Results represent the mean of 5–10 animals per group ± standard deviation. One-way ANOVA with Bonferroni post-test was performed to renal assessment using GraphPad Prism. * P<0.05 vs the control group – day 0, ** p<0.01 vs the control group – 0 days.</p