234 research outputs found
Persistent TFIIH binding to non-excised DNA damage causes cell and developmental failure
Congenital nucleotide excision repair (NER) deficiency gives rise to several cancer-prone and/or progeroid disorders. It is not understood how defects in the same DNA repair pathway cause different disease features and severity. Here, we show that the absence of functional ERCC1-XPF or XPG endonucleases leads to stable and prolonged binding of the transcription/DNA repair factor TFIIH to DNA damage, which correlates with disease severity and induces senescence features in human cells. In vivo, in C. elegans, this prolonged TFIIH binding to non-excised DNA damage causes developmental arrest and neuronal dysfunction, in a manner dependent on transcription-coupled NER. NER factors XPA and TTDA both promote stable TFIIH DNA binding and their depletion therefore suppresses these severe phenotypical consequences. These results identify stalled NER intermediates as pathogenic to cell functionality and organismal development, which can in part explain why mutations in XPF or XPG cause different disease features than mutations in XPA or TTDA.</p
Search for Charginos with a Small Mass Difference with the Lightest Supersymmetric Particle at \sqrt{s} = 189 GeV
A search for charginos nearly mass-degenerate with the lightest
supersymmetric particle is performed using the 176 pb^-1 of data collected at
189 GeV in 1998 with the L3 detector. Mass differences between the chargino and
the lightest supersymmetric particle below 4 GeV are considered. The presence
of a high transverse momentum photon is required to single out the signal from
the photon-photon interaction background. No evidence for charginos is found
and upper limits on the cross section for chargino pair production are set. For
the first time, in the case of heavy scalar leptons, chargino mass limits are
obtained for any \tilde{\chi}^{+-}_1 - \tilde{\chi}^0_1 mass difference
The association between antihypertensive drugs and glioma
We pursued an association between hypertension and gliomas by investigating whether antihypertensive drugs (AHD) are associated with an increased glioma risk by a population-based nested case–control study using the PHARMO database; this links dispensing records of prescription drugs to hospital discharge data on an individual basis. Pathological data were derived from the Dutch nationwide registry of histo- and cytopathology. A total of 306 glioma cases incident between 1997 and 2003 were matched to 1108 controls for year of birth, sex, geographical region and duration of follow-up. Exposure was defined as cumulative duration of AHD use and, in an alternative analysis, as cumulative dose. We estimated the magnitude of the association with conditional logistic regression analysis. Cumulative use of any AHD for more than 6 months was associated with an increased risk of glioma (OR 1.45; 95% CI 1.03–2.04). After stratification for different groups of AHD, no significantly increased risk of glioma was found for any class of AHD. After excluding a latency period of 3 years before the date of diagnosis, no association was found. In conclusion, the use of AHD seems to be associated with an increased risk of glioma, but this is probably not causal
Search for neutral B meson decays to two charged leptons
The decays are searched for in 3.5 million hadronic events, which constitute the full LEP I data sample collected by the L3 detector. No signals are observed, therefore upper limits at the 90\%(95\%) confidence levels are set on the following branching fractions: % \begin{center}% {\setlength{\tabcolsep}{2pt} \begin{tabular}{lccccclcccc}% % Br & & & & ; & \hspace*{5mm} & Br & & & & ; \\% Br & & & & ; & \hspace*{5mm} & Br & & & & ; \\% Br & & & & ; & \hspace*{5mm} & Br & & & & . \\% % \end{tabular}% } \end{center}% % The results for and are the first limits set on these decay modes
Search for neutral charmless B decays at LEP
A search for rare charmless decays of \Bd and \Bs mesons has been performed in the exclusive channels \Bd_{(\mathrm s)}\ra\eta\eta, \Bd_{(\mathrm s)}\ra\eta\pio and \Bd_{(\mathrm s)}\ra\pio\pio. The data sample consisted of three million hadronic \Zo decays collected by the L3 experiment at LEP from 1991 through 1994. No candidate event has been observed and the following upper limits at 90\% confidence level on the branching ratios have been set \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\eta)<4.1\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\eta)<1.5\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\pio)<2.5\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\pio)<1.0\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\pio\pio)<6.0\times 10^{-5},\,\, \mathrm{Br}(\Bs\ra\pio\pio)<2.1\times 10^{-4}. \end{displaymath} These are the first experimental limits on \Bd\ra\eta\eta and on the \Bs neutral charmless modes
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