Effect of levocarnitine/iron saccharate combination on renal anaemia and oxidative stress in patients undergoing haemodialysis

Purpose: To investigate the effect of a combination of levocarnitine and iron saccharate on the treatment of renal anaemia and oxidative stress in patients undergoing haemodialysis.Methods: A total of 156 patients with renal anaemia were divided randomly into control (78 cases) and test groups (78 cases). Patients in the control group were treated with erythropoietin (EPO), iron saccharate, and conventional symptomatic treatment, while patients in the test group were treated with levocarnitine additionally. Anaemia indices, oxidative stress indices, response rate, and EPO dose were compared.Results: At week 28, the levels of hemoglobin b (Hb), hematocrit (Hct), serum ferritin (SF), and transferrin saturation (TSAT) in the test group were 92.72 ± 12.51 g/L, 34.74 ± 5.89 vol %, 245.61 ± 81.35 ng/mL, and 24.34 ± 5.32 %, respectively, which were much lower than the levels in the test group (114.36 ± 12.27 g/L, 40.23 ± 5.78 vol %, 345.07 ± 85.93 ng/mL, and 29.76 ± 5.41 %, respectively; p < 0.05). The levels of advanced oxidation protein products (AOPP) and malonaldehyde (MDA) in the test group were much higher than those of the control group (121.77 ± 31.65 nmol/L vs 89.65 ± 30.53 nmol/L; 9.58 ± 2.64 nmol/L vs 4.81 ± 2.57 nmol/L, respectively (p < 0.05). EPO was maintained at a high dose from the beginning of treatment to week 28 in the control group, whereas in the test group, EPO dose was reduced gradually. The response rate in the test group was higher than that in the control group (92.30 % vs 76.90 %; p < 0.05).Conclusion: Levocarnitine/iron saccharate combination had a significant positive effect on the treatment of renal anaemia. It effectively relieved oxidative stress reactions and reduced the dose of EPO required.Keywords: Haemodialysis, Renal anaemia, Oxidative stress reaction, Levocarnitine, Iron saccharate, Erythropoieti

Curvature Effect of a Non-Power-Law Spectrum and Spectral Evolution of GRB X-Ray Tails

The apparent spectral evolution observed in the steep decay phase of many GRB early afterglows raises a great concern of the high-latitude "curvature effect" interpretation of this phase. However, previous curvature effect models only invoked a simple power law spectrum upon the cessation of the prompt internal emission. We investigate a model that invokes the "curvature effect" of a more general non-power-law spectrum and test this model with the Swift/XRT data of some GRBs. We show that one can reproduce both the observed lightcurve and the apparent spectral evolution of several GRBs using a model invoking a power-law spectrum with an exponential cut off. GRB 050814 is presented as an example.Comment: 12 pages, 4 figures, 1 table, . Accepted for publication in ApJ Letter

The Origin of the Prompt Emission for Short GRB 170817A: Photosphere Emission or Synchrotron Emission?

The first gravitational-wave event from the merger of a binary neutron star system (GW170817) was detected recently. The associated short gamma-ray burst (GRB 170817A) has a low isotropic luminosity (~1047 erg s−1) and a peak energy E p ~ 145 keV during the initial main emission between −0.3 and 0.4 s. The origin of this short GRB is still under debate, but a plausible interpretation is that it is due to the off-axis emission from a structured jet. We consider two possibilities. First, since the best-fit spectral model for the main pulse of GRB 170817A is a cutoff power law with a hard low-energy photon index ($\alpha =-{0.62}_{-0.54}^{+0.49}$), we consider an off-axis photosphere model. We develop a theory of photosphere emission in a structured jet and find that such a model can reproduce a low-energy photon index that is softer than a blackbody through enhancing high-latitude emission. The model can naturally account for the observed spectrum. The best-fit Lorentz factor along the line of sight is ~20, which demands that there is a significant delay between the merger and jet launching. Alternatively, we consider that the emission is produced via synchrotron radiation in an optically thin region in an expanding jet with decreasing magnetic fields. This model does not require a delay of jet launching but demands a larger bulk Lorentz factor along the line of sight. We perform Markov Chain Monte Carlo fitting to the data within the framework of both models and obtain good fitting results in both cases