Anesthetics, immune cells, and immune responses

post-prin

Dislocated dental bridge covering the larynx: usefulness of tracheal tube guides under video-assisted laryngoscopy for induction of general anesthesia, thus avoiding tracheostomy

BACKGROUND: To describe a case with dislodgement of dental bridge with clasps covering the vocal cords, in a patient who was successfully intubated using tube exchanger under video-assisted laryngoscopy. STUDY DESIGN, METHODS: Clinical case record with a video clip. SETTING: University hospital. CASE PRESENTATION: A 83-year-old woman presented with dislodgement of her dental bridge whilst eating. Laryngoscopy revealed a foreign body almost entirely covering the vocal cords, with the clasps of the dislodged partial denture piercing the pharyngeal wall. Before induction of general anesthesia, a tracheal tube introducer combined with video-assisted laryngoscopy was introduced into the trachea in the awake condition, followed by successful endotracheal intubation. Thereafter, the dislodged denture was extracted via the oral cavity. CONCLUSIONS: Tracheal tube introducers combined with video-assisted laryngoscopy appear to be useful for airway management, decreasing the number of avoidable tracheostomies performed

Feedback from Central Black Holes in Elliptical Galaxies: Two-dimensional Models Compared to One-dimensional Models

We extend the black hole (BH) feedback models of Ciotti, Ostriker, and Proga to two dimensions. In this paper, we focus on identifying the differences between the one-dimensional and two-dimensional hydrodynamical simulations. We examine a normal, isolated $L_*$ galaxy subject to the cooling flow instability of gas in the inner regions. Allowance is made for subsequent star formation, Type Ia and Type II supernovae, radiation pressure, and inflow to the central BH from mildly rotating galactic gas which is being replenished as a normal consequence of stellar evolution. The central BH accretes some of the infalling gas and expels a conical wind with mass, momentum, and energy flux derived from both observational and theoretical studies. The galaxy is assumed to have low specific angular momentum in analogy with the existing one-dimensional case in order to isolate the effect of dimensionality. The code then tracks the interaction of the outflowing radiation and winds with the galactic gas and their effects on regulating the accretion. After matching physical modeling to the extent possible between the one-dimensional and two-dimensional treatments, we find essentially similar results in terms of BH growth and duty cycle (fraction of the time above a given fraction of the Eddington luminosity). In the two-dimensional calculations, the cool shells forming at 0.1--1 kpc from the center are Rayleigh--Taylor unstable to fragmentation, leading to a somewhat higher accretion rate, less effective feedback, and a more irregular pattern of bursting compared to the one-dimensional case.Comment: 15 pages, 10 figures, ApJ 237:26. Updated to match published versio

Compensatory Thrombopoietin Production from the Liver and Bone Marrow Stimulates Thrombopoiesis of Living Rat Megakaryocytes in Chronic Renal Failure

Background/Aims: Decreased thrombopoiesis has been ascribed a role in the pathogenesis of uremic bleeding in chronic renal failure (CRF). However, serum thrombopoietin (TPO) levels are usually elevated in CRF patients, suggesting increased thrombopoiesis. The aim of this study was to determine the thrombopoietic activity in CRF. Methods: Male Sprague-Dawley rats that underwent 5/6 nephrectomy were used as the model of CRF. Age-matched sham-operated rats were used as controls. Single megakaryocytes were isolated from the rat bone marrow, and their size distribution was examined. Megakaryocyte membrane invaginations were monitored by confocal imaging of di-8-ANEPPS staining, and patch clamp whole-cell recordings of membrane capacitance. TPO gene expression was assessed in various tissues. Results: Circulating platelet counts and the number of large megakaryocytes were increased in the bone marrow of CRF rats. Massive di-8-ANEPPS staining and increased membrane capacitance in large megakaryocytes demonstrated increased membrane invaginations. Unaffected Kv1.3-channel currents per cell surface area demonstrated unaltered channel densities. TPO transcription was decreased in the renal cortex but increased in the liver and bone marrow of CRF rats. Conclusion: Increased thrombopoiesis in CRF was thought to be a reactive mechanism to platelet dysfunction. Increased TPO production from the liver and bone marrow compensated for decreased production from damaged kidneys

Environmental effects on the growth of super massive black holes and AGN feedback

We investigate how environmental effects by gas stripping alter the growth of a super massive black hole (SMBH) and its host galaxy evolution, by means of 1D hydrodynamical simulations that include both mechanical and radiative AGN feedback effects. By changing the truncation radius of the gas distribution (R_t), beyond which gas stripping is assumed to be effective, we simulate possible environments for satellite and central galaxies in galaxy clusters and groups. The continuous escape of gas outside the truncation radius strongly suppresses star formation, while the growth of the SMBH is less affected by gas stripping because the SMBH accretion is primarily ruled by the density of the central region. As we allow for increasing environmental effects - the truncation radius decreasing from about 410 to 50 kpc - we find that the final SMBH mass declines from about 10^9 to 8 x 10^8 Msol, but the outflowing mass is roughly constant at about 2 x 10^10 Msol. There are larger change in the mass of stars formed, which declines from about 2 x 10^10 to 2 x 10^9 Msol, and the final thermal X-ray gas, which declines from about 10^9 to 5 x 10^8 Msol, with increasing environmental stripping. Most dramatic is the decline in the total time that the objects would be seen as quasars, which declines from 52 Myr (for R_t = 377 kpc) to 7.9 Myr (for R_t = 51 kpc). The typical case might be interpreted as a red and dead galaxy having episodic cooling flows followed by AGN feedback effects resulting in temporary transitions of the overall galaxy color from red to green or to blue, with (cluster) central galaxies spending a much larger fraction of their time in the elevated state than do satellite galaxies.(Abridged)Comment: Accepted for publication in Ap

Differential roles of prostaglandin E-type receptors in activation of hypoxia-inducible factor 1 by prostaglandin E1 in vascular-derived cells under non-hypoxic conditions

Prostaglandin E1 (PGE1), known pharmaceutically as alprostadil, has vasodilatory properties and is used widely in various clinical settings. In addition to acute vasodilatory properties, PGE1 may exert beneficial effects by altering protein expression of vascular cells. PGE1 is reported to be a potent stimulator of angiogenesis via upregulation of VEGF expression, which is under the control of the transcription factor hypoxia-inducible factor 1 (HIF-1). However, the molecular mechanisms behind the phenomenon are largely unknown. In the present study, we investigated the mechanism by which PGE1 induces HIF-1 activation and VEGF gene expression in human aortic smooth muscle cells (HASMCs) and human umbilical vein endothelial cells (HUVECs), both vascular-derived cells. HUVECs and HASMCs were treated with PGE1 at clinically relevant concentrations under 20% O2 conditions and HIF-1 protein expression was investigated. Expression of HIF- 1α protein and the HIF-1-downstream genes were low under 20% O2 conditions and increased in response to PGE1 treatment in both HUVECs and HASMCs in a dose- and time-dependent manner under 20% O2 conditions as comparable to exposure to 1% O2 conditions. Studies using EP-receptor-specific agonists and antagonists revealed that EP1 and EP3 are critical to PGE1-induced HIF-1 activation. In vitro vascular permeability assays using HUVECs indicated that PGE1 increased vascular permeability in HUVECs. Thus, we demonstrate that PGE1 induces HIF- 1α protein expression and HIF-1 activation under non-hypoxic conditions and also provide evidence that the activity of multiple signal transduction pathways downstream of EP1 and EP3 receptors is required for HIF-1 activation

Feedback from central black holes in elliptical galaxies. III: models with both radiative and mechanical feedback

We find, from high-resolution hydro simulations, that winds from AGN effectively heat the inner parts (~100 pc) of elliptical galaxies, reducing infall to the central SMBH; and radiative (photoionization and X-ray) heating reduces cooling flows at the kpc scale. Including both types of feedback with (peak) efficiencies of 3 10^{-4} < epsilon_mech < 10^{-3} and of epsilon_rad ~10^{-1.3} respectively, produces systems having duty-cycles, central SMBH masses, X-ray luminosities, optical light profiles, and E+A spectra in accord with the broad suite of modern observations of massive elliptical systems. Our main conclusion is that mechanical feedback (including all three of energy, momentum and mass) is necessary but the efficiency, based on several independent arguments must be a factor of 10 lower than is commonly assumed. Bursts are frequent at z>1 and decline in frequency towards the present epoch as energy and metal rich gas are expelled from the galaxies into the surrounding medium. For a representative galaxy of final stellar mass ~3 10^{11} Msun, roughly 3 10^{10} Msun of recycled gas has been added to the ISM since z~2 and, of that, roughly 63% has been expelled from the galaxy, 19% has been converted into new metal rich stars in the central few hundred parsecs, and 2% has been added to the central SMBH, with the remaining 16% in the form hot X-ray emitting ISM. The bursts occupy a total time of ~170 Myr, which is roughly 1.4% of the available time. Of this time, the central SMBH would be seen as an UV or optical source for ~45% and ~71$% of the time, respectively. Restricting to the last 8.5 Gyr, the burst occupy ~44 Myr, corresponding to a fiducial duty-cycle of ~5 10^{-3}.Comment: 41 pages, 11 figures (bitmapped, low-quality), ApJ accepte

On the Feedback Efficiency of Active Galactic Nuclei

(Abridged) We measure and analyze the energy, momentum, and mass feedback efficiencies due to radiation from AGN in relatively large scale outflows. Our measurements are based on the axisymmetric and time-dependent radiation-hydrodynamical simulations recently presented in Kurosawa & Proga. These simulations follow dynamics of gas under the influences of the AGN radiation and the gravity of the central 10^8 Msun black hole on scales from ~0.01 to ~10pc. We compare our Mdot_a-rho_o relation with that predicted by the Bondi accretion model. For high luminosities comparable to the Eddington limit, the power-law fit (Mdot_a ~ rho_o^q) to our models yields q=~0.5 instead of q=1.0 which is predicted by the Bondi model. This difference is caused by the outflows which are important for the overall mass budget at high luminosities. The maximum momentum and mass feedback efficiencies found in our models are ~10^-2 and ~10^-1, respectively. However, the outflows are much less important energetically: their thermal and kinetic powers in units of the radiative luminosity are ~10^-5 and ~10^-4, respectively. The efficiencies do not increase monotonically with the accretion luminosity but rather peak around the Eddington limit beyond which a steady state disk-wind-like solution exists. Our energy feedback efficiencies are significantly lower than 0.05, which is required in some cosmological and galaxy merger simulations. The low feedback efficiencies found here could have significant implications on the mass growth of super massive black holes in the early universe. We stress however that we have not considered the innermost parts of the accretion and outflow where radiation and matter interact most strongly. The feedback from this region could have efficiencies significantly above the low values found here.Comment: 11 pages, 6 figures, accepted for publication in Ap

Feedback from central black holes in elliptical galaxies. II: Can purely mechanical energy feedback models work?

By using high-resolution 1D hydrodynamical simulations, we investigate the effects of purely mechanical feedback from super massive black holes (SMBHs) in the evolution of elliptical galaxies for a broad range of feedback efficiencies and compare the results to four major observational constraints. In particular, we focus on 1) the central black hole to stellar mass ratio of the host galaxy, 2) the lifetime of the luminous quasar phase, 3) the mass of stars formed in the host galaxy within the last Gyr, and 4) the X-ray luminosity of the hot diffuse gas. As a result, we try to pin down the most successful range of mechanical feedback efficiencies. We find that while low feedback efficiencies result in too much growth of the SMBH, high efficiencies totally blow out the hot interstellar gas, and the models are characterized by very low thermal X-ray luminosity well below the observed range. The net lifetime of the quasar phase is strongly coupled to the mass ratio between SMBH and its host galaxy, while the X-ray luminosity is generally correlated to the recent star formation within the last Gyr. When considering the popularly adopted model of the constant feedback efficiency, the feedback energy deposited into the ambient medium should be more than 0.01% of the SMBH accretion energy to be consistent with the SMBH mass to stellar mass ratio in the local universe. Yet, the X-ray luminosity of the hot gas favors about 0.005% of the accretion energy as the mechanical AGN feedback energy. We conclude that the purely mechanical feedback mode is unlikely to be simultaneously compatible with all four observable tests, even allowing a broad range of feedback efficiencies, and that including both radiative and mechanical feedback together may be a solution to comply the observational constraints. [abridged]Comment: Accepted to Ap