Neuro-inflammatory effects of photodegradative products of bilirubin

Phototherapy was introduced in the early 1950\u2019s, and is the primary treatment of severe neonatal jaundice or Crigler-Najjar syndrome. Nevertheless, the potential biological effects of the products generated from the photodegradation of bilirubin during phototherapy remain unknown. This is very relevant in light of recent clinical observations demonstrating that the use of aggressive phototherapy can increase morbidity or even mortality, in extremely low birthweight (ELBW) infants. The aim of our study was to investigate the effects of bilirubin, lumirubin (LR, its major photo-oxidative product), and BOX A and B (its monopyrrolic oxidative products) on the central nervous system (CNS) using in vitro and ex vivo experimental models. The effects of bilirubin photoproducts on cell viability and expression of selected genes were tested in human fibroblasts, three human CNS cell lines (neuroblastoma SH-SY5Y, microglial HMC3, and glioblastoma U-87 cell lines), and organotypic rat hippocampal slices. Neither bilirubin nor its photo-oxidative products affected cell viability in any of our models. In contrast, LR in biologically-relevant concentrations (25\u2009\u3bcM) significantly increased gene expression of several pro-inflammatory genes as well as production of TNF-\u3b1 in organotypic rat hippocampal slices. These findings might underlie the adverse outcomes observed in ELBW infants undergoing aggressive phototherapy

Luminosity-independent measurements of total, elastic and inelastic cross-sections at 1as = 7 TeV

The TOTEM experiment at the LHC has performed the first luminosity-independent determination of the total proton-proton cross-section at 1a s = 7TeV. This technique is based on the optical theorem and requires simultaneous measurements of the inelastic rate accomplished with the forward charged-particle telescopes T1 and T2 in the range 3.1 < |\u3b7| < 6.5 and of the elastic rate by detecting the outcoming protons with Roman Pot detectors. The data presented here were collected in a dedicated run in 2011 with special beam optics (\u3b2* = 90m) and Roman Pots approaching the beam close enough to register elastic events with squared four-momentum transfers |t| as low as 5 \ub7 10-3 GeV2. The luminosity-independent results for the elastic, inelastic and total cross-sections are \u3c3 el = (25.1 \ub11.1)mb, \u3c3inel = (72.9 \ub11.5)mb and \u3c3tot = (98.0 \ub12.5)mb, respectively. At the same time this method yields the integrated luminosity, in agreement with measurements by CMS. TOTEM has also determined the total cross-section in two complementary ways, both using the CMS luminosity measurement as an input. The first method sums the elastic and inelastic cross-sections and thus does not depend on the \u3c1 parameter. The second applies the optical theorem to the elastic-scattering measurements only and therefore is free of the T1 and T2 measurement uncertainties. The methods, having very different systematic dependences, give results in excellent agreement. Moreover, the \u3c1 -independent measurement makes a first estimate for the \u3c1 parameter at 1a s = 7TeV possible: |\u3c1| = 0.145 \ub10.091

Luminosity-independent measurement of the proton-proton total cross section at 1as=8 TeV

The TOTEM collaboration has measured the proton-proton total cross section at 1as=8 TeV using a luminosity-independent method. In LHC fills with dedicated beam optics, the Roman pots have been inserted very close to the beam allowing the detection of 3c90% of the nuclear elastic scattering events. Simultaneously the inelastic scattering rate has been measured by the T1 and T2 telescopes. By applying the optical theorem, the total proton-proton cross section of (101.7\ub12.9) mb has been determined, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: \u3c3el=(27.1\ub11.4) mb; \u3c3inel=(74. 7\ub11.7) mb

Measurement of proton-proton elastic scattering and total cross-section at 1as = 7 TeV

At the LHC energy of 1as = 7TeV, under various beam and background conditions, luminosities, and Roman Pot positions, TOTEM has measured the differential cross-section for proton-proton elastic scattering as a function of the four-momentum transfer squared t. The results of the different analyses are in excellent agreement demonstrating no sizeable dependence on the beam conditions. Due to the very close approach of the Roman Pot detectors to the beam enter ( 485\u3c3beam) in a dedicated run with \u3b2*= 90m, |t|-values down to 5\ub710-3 GeV-2 were reached. The exponential slope of the differential elastic cross-section in this newly explored |t|-region remained unchanged and thus an exponential fit with only one constant B = (19.9\ub10.3) GeV-2 over the large |t|-range from 0.005 to 0.2GeV2 describes the differential distribution well. The high precision of the measurement and the large fit range lead to an error on the slope parameter B which is remarkably small compared to previous experiments. It allows a precise extrapolation over the non-visible cross-section (only 9%) to t = 0. With the luminosity from CMS, the elastic crosssection was determined to be (25.4\ub11.1)mb, and using in addition the optical theorem, the total pp cross-section was derived to be (98.6\ub12.2)mb. For model comparisons the t-distributions are tabulated including the large |t|-range of the previous measurement (TOTEM Collaboration (Antchev G. et al.), EPL, 95 (2011) 41001)