497 research outputs found

    The association of stone opacity in plain radiography with percutaneous nephrolithotomy outcomes and complications

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    Purpose: To investigate the influence of stone opacity in plain radiography on stone free rate and complications of percutaneous nephrolithotomy (PCNL). Materials and Methods: A number of 101 patients who underwent PCNL between July-September 2015 were prospectively included. Stone opacity was judged on preoperative plain Kidney-Ureter-Bladder X-ray. Stone free rate was evaluated two weeks after the operation by ultrasonography and KUB. Results: There were 61 patients with opaque stones and 40 patients with non-opaque stones. The age, body mass index, preoperative creatinine, history of stone surgery, and stone size was not statistically different between patients with opaque and non-opaque stones. Neither operation duration nor access numbers were statistically significant between opaque and non-opaque stones. The frequency of stone free patients in opaque stones and nonopaque stones were 55/61 (90) and 30/40 (75) respectively (P = .04) The magnitude of hemoglobin drop in opaque stones and non-opaque stones were 1.9 ± 1.2 mg/dL versus 2.9 ± 1.7 mg/dL (P = .005). Conclusion: The stone free rate is lower and the magnitude of bleeding is higher in PCNL of non-opaque stones when compared to opaque stones if rigid instruments are used for nephroscopy

    Ultrasound - guided access during percutaneous nephrolithotomy: Entering desired calyx with appropriate entry site and angle

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    Objectives: To evaluate the success of ultrasonography directed renal access in entering the target calyx from proper entry site and in the direction of renal pelvis during percutaneous nephrolithotomy (PCNL). Materials and Methods: PCNL cases who were operated on by one fellow from May- June 2014 were included in this study. A vertically placed ultrasound probe on the patient flank in prone position was used to identify the preselected target calyx. Needle was advanced through needle holder and fluoroscopy was used to document the entered calyx, site and angle of entry. Results: Successful entering to the target calyx was achieved in 43 cases (91). Successful entry with appropriate entry site and angle was observed in 34 cases (72). Reasons for failure were minimal hydronephrosis, upper pole access and high lying kidneys. Conclusions: Although it is feasible to access a preselected calyx by ultrasonography guidance during PCNL, but entry to the calyx from the appropriate site and direction is another problem and needs more experience. In cases of minimal hydronephrosis, superior pole access or high lying kidneys, ultrasonography is less successful and should be used with care

    Inhibition of p73 Function by Pifithrin-α as Revealed by Studies in Zebrafish Embryos

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    The p53 family of proteins contains two members that have been implicated in sensitization of cells and organisms to genotoxic stress, i.e., p53 itself and p73. In vitro, lack of either p53 or p73 can protect certain cell types in the adult organism against death upon exposure to DNA damaging agents. The present study was designed to assess the relative contribution of p53 to radiation resistance of an emerging vertebrate model organism, i.e., zebrafish embryos. Consistent with previous reports, suppressing p53 protein expression using antisense morpholino oligonucleotides (MOs) increased survival and reduced gross morphological alterations in zebrafish embryos exposed to ionizing radiation. By contrast, a pharmacological inhibitor of p53 function [Pifithrin-α (PFTα)] caused developmental abnormalities affecting the head, brain, eyes and kidney function and did not protect against lethal effects of ionizing radiation when administered at 3 hours post fertilization (hpf). The phenotypic abnormalities associated with PFTα treatment were similar to those caused by antisense MO knock down (kd) used to reduce p73 expression. PFTα also inhibited p73-dependent transcription of a reporter gene construct containing canonical p53-responsive promoter sequences. Notably, when administered at later stages of development (23 hpf), PFTα did not cause overt developmental defects but exerted radioprotective effects in zebrafish embryos. In summary, this study highlights off-target effects of the pharmacological p53 inhibitor PFTα related to inhibition of p73 function and essential roles of p73 at early but not later stages of zebrafish development. Abreviations: MO, antisense morpholino oligonucleotide; PFTα, pifithrin-α; Hpf, hours post fertilization; Kd, knock down; IR, ionizing radiation Cell Cycle, Volume 7, Issue 9, pp. 1224-1230

    Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission

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    We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics (SPH) simulations of Eta Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectro-images of [Fe III] emission line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA {\theta} that the orbital plane projection of the line-of-sight makes with the apastron side of the semi-major axis, and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3-D orientation of the binary orbit. To simultaneously reproduce the blue-shifted emission arcs observed at orbital phase 0.976, STIS slit PA = +38 degrees, and the temporal variations in emission seen at negative slit PAs, the binary needs to have an i \approx 130 to 145 degrees, {\theta} \approx -15 to +30 degrees, and an orbital axis projected on the sky at a PA \approx 302 to 327 degrees east of north. This represents a system with an orbital axis that is closely aligned with the inferred polar axis of the Homunculus nebula, in 3-D. The companion star, Eta B, thus orbits clockwise on the sky and is on the observer's side of the system at apastron. This orientation has important implications for theories for the formation of the Homunculus and helps lay the groundwork for orbital modeling to determine the stellar masses.Comment: 23 pages, 12 color figures, plus 2 online-only appendices (available in the /anc folder of the Source directory). Accepted for publication in MNRA

    Polychromatic solitons in a quadratic medium

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    We introduce the simplest model to describe parametric interactions in a quadratically nonlinear optical medium with the fundamental harmonic containing two components with (slightly) different carrier frequencies [which is a direct analog of wavelength-division multiplexed (WDM) models, well known in media with cubic nonlinearity]. The model takes a closed form with three different second-harmonic components, and it is formulated in the spatial domain. We demonstrate that the model supports both polychromatic solitons (PCSs), with all the components present in them, and two types of mutually orthogonal simple solitons, both types being stable in a broad parametric region. An essential peculiarity of PCS is that its power is much smaller than that of a simple (usual) soliton (taken at the same values of control parameters), which may be an advantage for experimental generation of PCSs. Collisions between the orthogonal simple solitons are simulated in detail, leading to the conclusion that the collisions are strongly inelastic, converting the simple solitons into polychromatic ones, and generating one or two additional PCSs. A collision velocity at which the inelastic effects are strongest is identified, and it is demonstrated that the collision may be used as a basis to design a simple all-optical XOR logic gate.Comment: 9 pages, 8 figures, accepted to Phys. Rev.

    Detection of high-velocity material from the wind-wind collision zone of Eta Carinae across the 2009.0 periastron passage

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    We report near-IR spectroscopic observations of the Eta Carinae massive binary system during 2008-2009 using VLT/CRIRES. We detect a strong, broad absorption wing in He I 10833 extending up to -1900 km/s across the 2009.0 spectroscopic event. Archival HST/STIS ultraviolet and optical data shows a similar high-velocity absorption (up to -2100 km/s) in the UV resonance lines of Si IV 1394, 1403 across the 2003.5 event. UV lines from low-ionization species, such as Si II 1527, 1533 and C II 1334, 1335, show absorption up to -1200 km/s, indicating that the absorption with v from -1200 to -2100 km/s originates in a region markedly faster and more ionized than the nominal wind of the primary star. Observations obtained at the OPD/LNA during the last 4 spectroscopic cycles (1989-2009) also display high-velocity absorption in He I 10833 during periastron. Based on the OPD/LNA dataset, we determine that material with v < -900 km/s is present in the phase range 0.976 < phi < 1.023 of the spectroscopic cycle, but absent in spectra taken at phi < 0.947 and phi > 1.049. Therefore, we constrain the duration of the high-velocity absorption to be 95 to 206 days (or 0.047 to 0.102 in phase). We suggest that the high-velocity absorption originates from shocked gas in the wind-wind collision zone, at distances of 15 to 45 AU in the line-of-sight to the primary star. Using 3-D hydrodynamical simulations of the wind-wind collision zone, we find that the dense high-velocity gas is in the line-of-sight to the primary star only if the binary system is oriented in the sky so that the companion is behind the primary star during periastron, corresponding to a longitude of periastron of omega ~ 240 to 270 degrees. We study a possible tilt of the orbital plane relative to the Homunculus equatorial plane and conclude that our data are broadly consistent with orbital inclinations in the range i=40 to 60 degrees.Comment: 18 pages, 15 figures, accepted for publication in A&A; high-resolution PDF version available also at http://www.mpifr.de/staff/jgroh/etacar.htm
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