The mechanism coupling electron transfer and proton pumping in respiratory complex I (NADH-ubiquinone oxidoreductase) has not been established, but it has been suggested that it involves ...conformational changes. Here, the influence of substrates on the conformation of purified complex I from Escherichia coli was studied by cross-linking and electron microscopy. When a zero-length cross-linking reagent was used, the presence of NAD(P)H, in contrast to that of NAD+, prevented the formation of cross-links between the hydrophilic subunits of the complex, including NuoB, NuoI, and NuoCD. Comparisons using different cross-linkers suggested that NuoB, which is likely to coordinate the key iron-sulfur cluster N2, is the most mobile subunit. The presence of NAD(P)H led also to enhanced proteolysis of subunit NuoG. These data indicate that upon NAD(P)H binding, the peripheral arm of the complex adopts a more open conformation, with increased distances between subunits. Single particle analysis showed the nature of this conformational change. The enzyme retains its L-shape in the presence of NADH, but exhibits a significantly more open or expanded structure both in the peripheral arm and, unexpectedly, in the membrane domain also.
The molecular organization of bacterial NADH: ubiquinone oxidoreductase (complex I or NDH-1) is not established, apart from a rough separation into dehydrogenase, connecting and membrane domains. In ...this work, complex I was purified from Escherichia coli and fragmented by replacing dodecylmaltoside with other detergents. Exchange into decyl maltoside led to the removal of the hydrophobic subunit NuoL from the otherwise intact complex. Diheptanoyl phosphocholine led to the loss of NuoL and NuoM subunits, whereas other subunits remained in the complex. The presence of N,N-dimethyldodecylamine N-oxide or Triton X-100 led to further disruption of the membrane domain into fragments containing NuoL/M/N, NuoA/K/N, and NuoH/J subunits. Among the hydrophilic subunits, NuoCD was most readily dissociated from the complex, whereas NuoB was partially dissociated from the peripheral arm assembly in N,N-dimethyldodecylamine N-oxide. A model of subunit arrangement in bacterial complex I based on these data is proposed. Subunits NuoL and NuoM, which are homologous to antiporters and are implicated in proton pumping, are located at the distal end of the membrane arm, spatially separated from the redox centers of the peripheral arm. This is consistent with proposals that the mechanism of proton pumping by complex I is likely to involve long range conformational changes.
The prudent selection of surgical gloves can deliver significant efficiency savings. However, objective data are lacking to compare differences in cutaneous sensibility between competing gloves. ...Therefore, the present study examined the use of a single comparable model of sterile surgical glove from two competing providers, Gammex PF HyGrip(®) (Ansell Limited, Red Bank, NJ, USA) with Biogel(®) (Mölnlycke Health Care AB, Göteborg, Sweden).
Cutaneous pressure threshold, static and moving two-point discrimination were measured as indices of objective surgical glove performance in 52 blinded healthcare professionals.
The mean cutaneous pressure threshold was 0.0680 ± 0.0923 g for skin, 0.411 ± 0.661 g for Ansell gloves and 0.472 ± 0.768 g for Biogel gloves. Skin was significantly more sensitive than Ansell (P < 0.0001) or Biogel (P < 0.0001) gloves (Wilcoxon signed rank test). There was no statistical difference between Biogel and Ansell gloves (P = 0.359). There was no significant difference between static or moving 2-point discrimination of skin and Ansell gloves (P = 0.556, P = 0.617; Wilcoxon signed rank test), skin and Biogel gloves (P = 0.486, P = 0.437; Wilcoxon signed rank test) or Ansell and Biogel gloves (P = 0.843, P = 0.670; Wilcoxon signed rank test).
No demonstrable objective difference was found between competing gloves in the outcome measures of cutaneous sensibility and two-point discrimination. However, a difference in subjective preference was noted. Untested factors may underlie this discrepancy, and further research should employ more sophisticated measurements of surgical performance using competing models of surgical glove.
A search for single top production (e(+)e(-) --> t (c) over bar) via flavour changing neutral currents (FCNC) was performed using the data taken by the DELPHI detector at LEP2. The data analyzed have ...been accumulated at center-of-mass energies ranging from 189 to 208 GeV. Limits at 95% confidence level were obtained on the anomalous coupling parameters kappa(gamma) and kappa(Z). (C) 2004 Published by Elsevier B.V.
Various paraneoplastic autoantibodies have been linked to discrete neurologic syndromes and tumors in adults, but little is known about their incidence in children. We report a cross-sectional study ...of known paraneoplastic antibodies in 59 children with opsoclonus-myoclonus-ataxia, 86% of whom were moderately or severely symptomatic, and 68% of whom had relapsed at the time of testing. This total number of patients includes 18 children with low-stage neuroblastoma (tested after tumor resection), six of whom had never been treated with immunosuppressants. All were seronegative for anti-Hu, anti-Ri, and anti-Yo, the three paraneoplastic antibodies most associated with opsoclonus-myoclonus or ataxia in adults. These data contrast with reports of anti-Hu-positive sera in children with high-stage tumors and suggest that anti-Hu, anti-Ri, and anti-Yo do not explain relapses in pediatric opsoclonus-myoclonus-ataxia. They underscore the need to search for unique autoantibodies, as well as cellular mechanisms of pediatric paraneoplastic disease.
Searches for HZ production with the Higgs boson decaying into an invisible final state were performed using the data collected by the DELPHI experiment at centre-of-mass energies between 188 GeV and ...209 GeV. Both hadronic and leptonic final states of the Z boson were analysed. In addition to the search for a heavy Higgs boson, a dedicated search for a light Higgs boson down to 40 GeV/c2 was performed. No signal was found. Assuming the Standard Model HZ production cross-section, the mass limit for invisibly decaying Higgs bosons is 112.1 GeV/c2 at 95% confidence level. An interpretation in the Minimal Supersymmetric extension of the Standard Model (MSSM) and in a Majoron model is also given.
Anemia during radiation therapy independently predicts poor outcome in patients with cervical cancer. Despite a randomized trial demonstrating red cell transfusions improve local control and ...survival, many patients are not transfused due to toxicity concerns. This study evaluates the efficacy of recombinant human erythropoietin (r-HuEPO) in reversing anemia in patients undergoing radiation therapy.
Twenty patients with criteria of anemia (Hgb < 12.5 g/dL) and surgically staged cervical cancer FIGO stages IB (n = 7), IIA (n = 1), IIB (n = 9), and IIIB (n = 3), ranging in ages from 23-75 years (median 43), were included in this Phase I/II study. Fifteen were treated with r-HuEPO (200 U/kg/day) and ferrous sulfate 5-10 days prior to initiation of external beam radiation therapy, continuing until Hgb was < or = 14 g/dL or completion of radiation therapy. Five patients were treated with ferrous sulfate alone. An additional 61 historical controls meeting eligibility criteria were analyzed. All received external beam radiation therapy and two intracavitary cesium applications. Cisplatinum chemotherapy (20 mg/m2/week) was given as a radiosensitizer in 14 r-HuEPO patients, 4 concurrent controls, and 17 historical controls.
A marked reticulocytosis was seen in the r-HuEPO group, but not the study controls. In the r-HuEPO group, the mean +/- SD serum Hgb rose + 30% over the course of radiation therapy from a baseline of 10.3 +/- 1.04 g/dL to 13.2 +/- 1.7 g/dL. Average increase in Hgb was 0.5 g/dL per week. Average Hgb during RT was 13.4 g/dL. In study and historical controls, mean initial Hgb levels were 10.7 +/- 1.04 g/dL and 11.1 +/- 1.3g/dL, respectively, remaining unchanged over the course of radiation therapy. Average Hgb levels during radiation therapy were 11.1 g/dL in study controls and 11.4 g/dL in historical controls, significantly lower than r-HuEPO patients (p = 0.0001). Erythropoietin was well tolerated. There were no significant differences in white blood counts (p = 0.6) or platelet counts (p = 0.4) between r-HuEPO patients and both control groups. No patients had blood pressure changes during r-HuEPO therapy. The only possible side effect was deep venous thrombosis, occurring in two patients who were withdrawn from r-HuEPO therapy. Two additional patients developed deep venous thrombosis 9 and 10 days after radiation therapy and r-HuEPO were completed.
Erythropoietin appears to be both safe and effective at raising Hgb levels in anemic cervical cancer patients receiving radiation therapy and chemotherapy.
Whole-cell suspensions of Cylindrocarpon didymum were observed to transform 2,2'-bimorphine to the compounds 10-alpha-S-monohydroxy-2,2'-bimorphine and ...10,10'-alpha,alpha'-S,S'-dihydroxy-2,2'-bimorphine. Mass spectrometry and (1)H nuclear magnetic resonance spectroscopy confirmed the identities of these new morphine alkaloids.
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