Loss of the high-affinity pentamidine transporter is responsible for high levels of cross-resistance between arsenical and diamidine drugs in African trypanosomes

Treatment of many infectious diseases is under threat from drug resistance. Understanding the mechanisms of resistance is as high a priority as the development of new drugs. We have investigated the basis for cross-resistance between the diamidine and melaminophenyl arsenical classes of drugs in African trypanosomes. We induced high levels of pentamidine resistance in a line without the tbat1 gene that encodes the P2 transporter previously implicated in drug uptake. We isolated independent clones that displayed very considerable cross-resistance with melarsen oxide but not phenylarsine oxide and reduced uptake of [(3)H]pentamidine. In particular, the high-affinity pentamidine transport (HAPT1) activity was absent in the pentamidine-adapted lines, whereas the low affinity pentamidine transport (LAPT1) activity was unchanged. The parental tbat1(-/-) line was sensitive to lysis by melarsen oxide, and this process was inhibited by low concentrations of pentamidine, indicating the involvement of HAPT1. This pentamidine-inhibitable lysis was absent in the adapted line KO-B48. Likewise, uptake of the fluorescent diamidine 4',6-diamidino-2-phenylindole dihydrochloride was much delayed in live KO-B48 cells and insensitive to competition with up to 10 muM pentamidine. No overexpression of the Trypanosoma brucei brucei ATP-binding cassette transporter TbMRPA could be detected in KO-B48. We also show that a laboratory line of Trypanosoma brucei gambiense, adapted to high levels of resistance for the melaminophenyl arsenical drug melarsamine hydrochloride (Cymelarsan), had similarly lost TbAT1 and HAPT1 activity while retaining LAPT1 activity. It seems therefore that selection for resistance to either pentamidine or arsenical drugs can result in a similar phenotype of reduced drug accumulation, explaining the occurrence of cross-resistance.

Structural model of the CopA copper ATPase of Enterococcus hirae based on chemical cross-linking

The CopA copper ATPase of Enterococcus hirae belongs to the family of heavy metal pumping CPx-type ATPases and shares 43% sequence similarity with the human Menkes and Wilson copper ATPases. Due to a lack of suitable protein crystals, only partial three-dimensional structures have so far been obtained for this family of ion pumps. We present a structural model of CopA derived by combining topological information obtained by intramolecular cross-linking with molecular modeling. Purified CopA was cross-linked with different bivalent reagents, followed by tryptic digestion and identification of cross-linked peptides by mass spectrometry. The structural proximity of tryptic fragments provided information about the structural arrangement of the hydrophilic protein domains, which was integrated into a three-dimensional model of CopA. Comparative modeling of CopA was guided by the sequence similarity to the calcium ATPase of the sarcoplasmic reticulum, Serca1, for which detailed structures are available. In addition, known partial structures of CPx-ATPase homologous to CopA were used as modeling templates. A docking approach was used to predict the orientation of the heavy metal binding domain of CopA relative to the core structure, which was verified by distance constraints derived from cross-links. The overall structural model of CopA resembles the Serca1 structure, but reveals distinctive features of CPx-type ATPases. A prominent feature is the positioning of the heavy metal binding domain. It features an orientation of the Cu binding ligands which is appropriate for the interaction with Cu-loaded metallochaperones in solution. Moreover, a novel model of the architecture of the intramembranous Cu binding sites could be derived.

[Cross-talk between heart and kidney--mechanisms and management of the cardiorenal syndrome from a nephrologists view]

Renal dysfunction represents a frequent comorbidity in patients with in chronic heart failure and is not only a strong predictor of mortality, but also causally linked to the development and progression of CHF. Mechanisms involved in the cross-talk between the kidney and the heart include the up-regulated sympathetic nerve system, activation of the renin-angiotensin-aldosterone system, vasopressin release and decreased activity of arterial baroreceptors and natriuretic peptides resulting in abnormal salt and water retention. The main therapeutic goals for patients with the so-called cardiorenal syndrome is the normalization of volume status while avoiding overdiuresis and renal dysfunction as well as the implementation of an evidence-based pharmacologic treatment to improve patient outcome. If these two goals are not achieved with conventional therapy, renal replacement therapy should be discussed in an interdisciplinary approach. All current renal replacement techniques have proved to be useful in controlling hypervolemia and ameliorating functional cardiac parameters and quality of life in patients with heart failure. Nevertheless, the influence of renal replacement therapy on long-term survival of affected patients has not been addressed in large controlled studies.

Frequency of use and knowledge of the WHO-surgical checklist in Swiss hospitals: a cross-sectional online survey

BACKGROUND The WHO-surgical checklist is strongly recommended as a highly effective yet economically simple intervention to improve patient safety. Its use and potentially influential factors were investigated as little data exist on the current situation in Switzerland. METHODS A cross-sectional online survey with members (N = 1378) of three Swiss professional associations of invasive health care professionals was conducted in German, French, and Italian. The survey assessed use of, knowledge of and satisfaction with the WHO-surgical checklist. T-Tests and ANOVA were conducted to test for differences between professional groups. Bivariate correlations were computed to test for associations between measures of knowledge and satisfaction. RESULTS 1090 (79.1%) reported the use of a surgical checklist. 346 (25.1%) use the WHO-checklist, 532 (38.6%) use the Swiss Patient Safety Foundation recommendations to avoid Wrong Site Surgery, and 212 (15.7%) reported the use of other checklists. Satisfaction with checklist use was generally high (doctors: 71.9% satisfied, nurses: 60.8% satisfied) and knowledge was moderate depending on the use of the WHO-checklist. No association between measures of subjective and objective knowledge was found. CONCLUSIONS Implementation of a surgical checklist remains an important task for health care institutions in Switzerland. Although checklist use is present in Switzerland on a regular basis, a substantial group of health care personnel still do not use a checklist as a routine. Influential factors and the associations among themselves need to be addressed in future studies in more detail.

Handbook of LHC Higgs Cross Sections: 3. Higgs Properties. Report of the LHC Higgs Cross Section Working Group

This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered particle such as couplings to SM particles, spin and CP-quantum numbers etc.

Measurement of the high-mass Drell–Yan differential cross-section in pp collisions at with the ATLAS detector

This Letter reports a measurement of the high-mass Drell-Yan differential cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. Based on an integrated luminosity of 4.9 fb^-^1, the differential cross-section in the Z/@c^@?->e^+e^- channel is measured with the ATLAS detector as a function of the invariant mass, m_e_e, in the range 116the electron and the positron have transverse momentum p_T>25 GeV and pseudorapidity |@h|<2.5. A comparison is made to various event generators and to the predictions of perturbative QCD calculations at next-to-next-to-leading order.

Microbial-immune cross-talk and regulation of the immune system

We are all born germ-free. Following birth we enter into a lifelong relationship with microbes residing on our body's surfaces. The lower intestine is home to the highest microbial density in our body, which is also the highest microbial density known on Earth (up to 10(12) /g of luminal contents). With our indigenous microbial cells outnumbering our human cells by an order of magnitude our body is more microbial than human. Numerous immune adaptations confine these microbes within the mucosa, enabling most of us to live in peaceful homeostasis with our intestinal symbionts. Intestinal epithelial cells not only form a physical barrier between the bacteria-laden lumen and the rest of the body but also function as multi-tasking immune cells that sense the prevailing microbial (apical) and immune (basolateral) milieus, instruct the underlying immune cells, and adapt functionally. In the constant effort to ensure intestinal homeostasis, the immune system becomes educated to respond appropriately and in turn immune status can shape the microbial consortia. Here we review how the dynamic immune-microbial dialogue underlies maturation and regulation of the immune system and discuss recent findings on the impact of diet on both microbial ecology and immune function.

Measurement of the ttbar production cross section in the tau+jets channel using the ATLAS detector

A measurement of the top quark pair production cross section in the final state with a hadronically decaying tau lepton and jets is presented. The analysis is based on proton-proton collision data recorded by the ATLAS experiment at the LHC, with a centre-of-mass energy of 7 TeV. The data sample corresponds to an integrated luminosity of 1.67 fb(-1). The cross section is measured to be sigma(t (t) over bar) = 194 +/- 18 (stat.) +/- 46 (syst.) pb and is in agreement with other measurements and with the Standard Model prediction.