Search for production of single top quarks via tcg and tug flavor-changing-neutral-current couplings

We search for the production of single top quarks via flavor-changing-neutral-current couplings of a gluon to the top quark and a charm (c) or up (u) quark. We analyze 230 pb{-1} of lepton+jets data from pp[over] collisions at a center of mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We observe no significant deviation from standard model predictions, and hence set upper limits on the anomalous coupling parameters kappa{g}{c}/Lambda and kappa{g}{u}/Lambda, where kappa{g} define the strength of tcg and tug couplings, and Lambda defines the scale of new physics. The limits at 95% C.L. are kappa{g}{c}/Lambda<0.15 TeV-1 and kappa{g}{u}/Lambda<0.037 TeV-1.

Measurement of the Lambdab0 lifetime using semileptonic decays

We report a measurement of the Lambda(b)(0) lifetime using a sample corresponding to 1.3 fb(-1) of data collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. The Lambda(b)(0) baryon is reconstructed via the decay Lambda(b)(0)-->micronuLambda(c)(+)X. Using 4437+/-329 signal candidates, we measure the Lambda(b)(0) lifetime to be tau(Lambda(b)(0))=1.290(-0.110)(+0.119)(stat)(-0.091)(+0.087)(syst) ps, which is among the most precise measurements in semileptonic Lambda(b)(0) decays. This result is in good agreement with the world average value.

Inter-comparison of absorbed dose rates for non-human biota

A number of approaches have been proposed to estimate the exposure of non-human biota to ionizing radiation. This paper reports an inter-comparison of the unweighted absorbed dose rates for the whole organism (compared as dose conversion coefficients, or DCCs) for both internal and external exposure, estimated by 11 of these approaches for selected organisms from the Reference Animals and Plants geometries as proposed by the International Commission on Radiological Protection. Inter-comparison results indicate that DCCs for internal exposure compare well between the different approaches, whereas variation is greater for external exposure DCCs. Where variation among internal DCCs is greatest, it is generally due to different daughter products being included in the DCC of the parent. In the case of external exposures, particularly to low-energy beta-emitters, variations are most likely to be due to different media densities being assumed. On a radionuclide-by-radionuclide basis, the different approaches tend to compare least favourably for (3)H, (14)C and the alpha-emitters. This is consistent with models with different source/target geometry assumptions showing maximum variability in output for the types of radiation having the lowest range across matter. The intercomparison demonstrated that all participating approaches to biota dose calculation are reasonably comparable, despite a range of different assumptions being made.

Properties of L=1 B(1) and B(2)* mesons

This Letter presents the first strong evidence for the resolution of the excited B mesons B(1) and B(2)* as two separate states in fully reconstructed decays to B(+)(*)pi(-). The mass of B(1) is measured to be 5720.6+/-2.4+/-1.4 MeV/c(2) and the mass difference DeltaM between B(2)* and B(1) is 26.2+/-3.1+/-0.9 MeV/c;{2}, giving the mass of the B(2)* as 5746.8+/-2.4+/-1.7 MeV/c(2). The production rate for B(1) and B(2)* mesons is determined to be a fraction (13.9+/-1.9+/-3.2)% of the production rate of the B+ meson.

Measurement of the Lambda b lifetime in the exclusive decay Lambda b --> J/psi Lambda

We have measured the Lambda b lifetime using the exclusive decay Lambda b --> J/psi Lambda, based on 1.2 fb(-1) of data collected with the D0 detector during 2002-2006. From 171 reconstructed Lambda b decays, where the J/psi and Lambda are identified via the decays J/psi --> mu+ mu- and Lambda --> ppi, we measured the Lambda b lifetime to be tau(Lambda b)=1.218 (+0.130)/(-0.115) (stat) +/- 0.042(syst) ps. We also measured the B0 lifetime in the decay B0 --> J/psi(mu+ mu-)K(0)/(S)(pi+ pi-) to be tau(B0)=1.501 (+0.078)/(-0.074) (stat) +/- 0.050(syst) ps, yielding a lifetime ratio of tau(Lambda b)/tau(B0)=0.811 (+0.096)/(-0.087) (stat) +/- 0.034(syst).

Pharmacokinetics and urinary excretion of eprosartan in Chinese healthy volunteers of different gender

The study aims to evaluate the pharmacokinetics and urinary excretion of eprosartan in Chinese healthy volunteers and to study the effect of gender on pharmacokinetics of eprosartan. Twenty healthy volunteers (ten men and ten women) were recruited for an open trial and received a single dose of 600 mg eprosartan. Using a validated LC/MS/MS method, plasma and urinary concentrations of eprosartan were determined. The following pharmacokinetic parameters were elucidated after administration: the area under the plasma concentration versus time curve from 0 to 32 h (AUC0-32h) 14818.75 +/- 7312.11 ng x h/mL, the area under the plasma concentration versus time curve from 0 to infinite (AUC(0-infinity)) 15081.62 +/- 7379.63 ng x h/mL, peak plasma concentration (Cmax) 3664.25 x 1653.94 ng x h/mL, time to Cmax (Tmax) 1.63 +/- 0.46 h, elimination half-life (t(1/2)) 8.03 +/- 4.04 h, apparent clearance (CL/F) 47.84 +/- 19.21 L/h, apparent volume of distribution of the central compartment (V/F) 537.21 +/- 287.91 L, renal clearance (CLr) 1.33 +/- 0.41 L/h, amount of unchanged eprosartan excreted into urine 18.44 +/- 6.43 mg and fraction of unchanged eprosartan excreted into urine 3.07 +/- 1.07%. Our results also indicated that no gender differences were observed in the pharmacokinetics of eprosartan in Chinese healthy volunteers.

Search for stopped gluinos from pp collisions at square root s = 1.96 TeV

Long-lived, heavy particles are predicted in a number of models beyond the standard model of particle physics. We present the first direct search for such particles' decays, occurring up to 100 h after their production and not synchronized with an accelerator bunch crossing. We apply the analysis to the gluino (g), predicted in split supersymmetry, which after hadronization can become charged and lose enough momentum through ionization to come to rest in dense particle detectors. Approximately 410 pb(-1) of pp collisions at square root(s) = 1.96 TeV collected with the D0 detector during Run II of the Fermilab Tevatron collider are analyzed in search of such "stopped gluinos" decaying into a gluon and a neutralino (chi(1)(0)). Limits are placed on the (gluino cross section) x (probability to stop) x [BR(g --> g chi(1)(0))] as a function of the gluino and chi(1)(0) masses, for gluino lifetimes from 30 micros-100 h.

Search for third-generation scalar leptoquarks in pp at square root s=1.96 TeV

We report on a search for charge-1/3 third-generation leptoquarks (LQ) produced in pp collisions at square root s =1.96 TeV using the D0 detector at Fermilab. Third-generation leptoquarks are assumed to be produced in pairs and to decay to a tau neutrino and a b quark with branching fraction B. We place upper limits on sigma(pp --> LQLQ)B2 as a function of the leptoquark mass M(LQ). Assuming B=1, we exclude at the 95% confidence level third-generation scalar leptoquarks with M(LQ)<229 GeV.

Direct observation of the strange b baryon Xib-

We report the first direct observation of the strange b baryon Xi(b)- (Xi(b)+). We reconstruct the decay Xi(b)- -->J/psiXi-, with J/psi-->mu+mu-, and Xi--->Lambdapi--->ppi-pi- in pp collisions at square root of s =1.96 TeV. Using 1.3 fb(-1) of data collected by the D0 detector, we observe 15.2 +/- 4.4(stat)(-0.4)(+1.9)(syst) Xi(b)- candidates at a mass of 5.774 +/- 0.011(stat) +/- 0.015(syst) GeV. The significance of the observed signal is 5.5 sigma, equivalent to a probability of 3.3 x 10(-8) of it arising from a background fluctuation. Normalizing to the decay Lambda(b)-->J/psiLambda, we measure the relative rate sigma(Xi(b-) x B(Xi)b})- -->J/psiXi-)/sigma(Lambda(b)) x B(Lambda(b)-->J/psiLambda) = 0.28+/-0.09(stat)(-0.08)(+0.09)(syst).

Gemcitabine plus conventional-dose epirubicin versus gemcitabine plus cisplatin as first-line chemotherapy for stage IIIB/IV non-small cell lung carcinoma: A randomized phase II trial

18072

Background: Epirubicin is active for treatment of non-small cell lung carcinoma (NSCLC) but its optimal dose was undetermined. This study was designed to evaluate the efficacy and safety of gemcitabine plus conventional-dose epirubicin for stage IIIB/IV NSCLC. Methods: Patients with histological or cytological diagnosis of stage IIIB/IV NSCLC who had not received prior chemotherapy were eligible. Patients were randomized to GE (gemcitabine, 1,000 mg/m2 on days 1, 8, and 15 and epirubicin, 70 mg/m2 on day 15) or GC (gemcitabine, 1,000 mg/m2 on days 1, 8, and 15 and cisplatin, 80 mg/m2 on day 15). Treatment cycles were repeated every 4 weeks. Objective tumor response and toxicity were evaluated by using the World Health Organization criteria. Results: No significant difference in baseline characteristics between patients randomized to GC (n=41) and GE (n=39) arms were found. The objective response rate was 31.0% (95% C.I. 16.4% to 45.5) for GC and 37.2.0% (95% C.I. 22.2% to 52.3%) for GE. The median time-to-treatment-failure and overall survival were 6.1 months (95% C.I. 4.9 to 7.4 months) and 13.2 months (95% C.I. 8.9 to 17.5 months) for GC and 6.2 months (95% C.I. 5.2 to 7.2 months) and 21.2 months (95% C.I. 14.6 to 27.8 months) for GE, respectively. More grade 3/4 neutropenia (71.8%) was noted in GE than in GC (43.9%). Febrile neutropenia was also more common in GE (4 patients) than in GC (1 patient). However, delay of protocol treatment due to leukopenia was similar between the 2 arms. Data on the expresssion of the excission repair cross-complimentation 1 (ERCC1), evaluated by immunohistochemical study for patients with available tumor tissue, will be presented. Conclusions: Gemcitabine plus conventional-dose epirubicin is an effective and well-tolerated regimen for patients with stage IIIB/IV NSCLC.

No significant financial relationships to disclose.

The association of epidermal growth factor receptor (EGFR) polymorphisms and clinicopathological factors with skin rash on gefitinib use

18118

Background: Skin rash is the most common toxicity of EGFR-targeted therapy. Skin rash of EGFR inhibitor is associated with longer survival or tumor response. However, the clinical and genetic factors associated with this skin rash are not well understood. Methods: Fifty-two non-small-cell lung cancer patients enrolled in a prospective clinical trial of first-line gefitinib treatment were genotyped for EGFR intron 1 CA repeat polymorphism (CAn) and single nucleotide polymorphisms at promoters G-216T, C-191A, and R521K. Grade 2 to 3 skin rash within 4 weeks of treatment (early G2/3 rash) was correlated with the genotype and clinicopathological features of the patients by multivariate logistic regression. Results: Seventeen patients (32.7%) developed early G2/3 rash. In multivariate logistic regression analysis, only the CAn genotype was associated with early G2/3 rash and the effect was modified by patient age. Early G2/3 rash developed in 21% of patients with homozygous long allele (19 to 22 repeats, L) genotype (4/19), 31% of heterozygous short allele (15 to 18 repeats, S) / L genotype (8/26), and 71% of S/S genotype (5/7), respectively. The median ages of patients with early G2/3 rash and patients without early G2/3 rash were 57 years (range: 39–77) and 69 years (range: 43–86), respectively. The estimated logarithm of odds ratio (ln OR) for early G2/3 rash, as compared to S/S genotype, for S/L genotype was -0.038 multiplied by patient age (P = 0.011); and the ln OR for L/L genotype was -0.050 multiplied by patient age (P = 0.004). Fifty patients were evaluable for response. In logistic regression analysis, early G2/3 rash correlated with tumor response (P = 0.027). However, the CAn genotype was not significantly correlated with tumor response (P = 0.43). Conclusions: Homozygous short allele of EGFR CAn is more likely to develop skin rashes on gefitinib treatment. Genotyping of EGFR CAn appears to be a useful predictive marker for development of skin rashes on gefitinib use.

[Table: see text]

Potentiation of proteasome inhibitor-induced apoptosis in glioma cells by histone deacetylase inhibitors

2038

The effects of combining histone deacetylase (HDAC) inhibitors and proteasome inhibitors were evaluated in both established glioblastoma multiforme (GBM) cell lines and short-term cultures derived from the Mayo Clinic xenograft GBM panel. Co-exposure of LBH589 (LBH) and botezomib (btzmb) results in a striking induction of apoptosis, at minimally toxic doses of either drug alone, in established U251, U87, and D37 GBM cell lines, as well as in GBM8 (G-8), GBM10 (G-10), GBM12 (G-12), GBM14 (G-14), and GBM56 (G-56) cells, which have been developed from the Mayo xenograft GBM panel and maintained in short-term cultures. Synergism of apoptosis induction was also observed in U251 cells when co-exposing other HDAC inhibitors, including LAQ824 (LAQ) and trichostatin A (TSA), with another proteasome inhibitor MG132, demonstarting a class effect. In U251 cells, btzmb alone or in combination with LBH decreased Raf-1 levels and inactivated Akt and Erk. Either LBH589 or bortezomib alone increased expression of the cell cycle regulators p21 and p27. Additionally, the combination, but not the individual agents, markedly increased JNK activation. In addition, cell death after exposure to LBH589 and bortezomib is associated with cytochrome c release, Bax translocation, as well as caspase and PARP cleavage. Bax translocation may contribute to the synergistic cytotoxicity of the combination of LBH and btzmb in glioma cells since Bax translocation to mitochondria is known to precede cytochrome c release and apoptosis, but other pathways are likely to be involved. This combination regimen warrants further preclinical and possible clinical study for glioma patients.

No significant financial relationships to disclose.

Randomized trial of postoperative adjuvant therapy in stage II and III rectal cancer to define the optimal sequence of chemotherapy and radiotherapy: A final report

4050

Background: We conducted a prospective randomized trial to define the optimal sequence of chemotherapy and radiotherapy of postoperative adjuvant treatment in stage II and III rectal cancer. Methods: Three hundred eight patients were enrolled onto the study. We randomly assigned 155 to arm I (early radiotherapy group) and 153 to arm II (late radiotherapy group). Treatment included eight cycles of chemotherapy at 4-week intervals and pelvic radiotherapy of 45 Gy in 25 fractions. Radiotherapy started on day 1 of the first chemotherapy cycle in arm I and on day 1 of the third chemotherapy cycle in arm II. The chemotherapy regimen consisted of fluorouracil 375 mg/m2/d and leucovorin 20 mg/m2/d. Chemotherapy was administered for 3 days per cycle in two cycles during the period of radiotherapy and for 5 days per cycle in the remaining six cycles. (J Clin Oncol 2002 20:1751- 8) Results: Twenty patients in arm I and 14 in arm II were not eligible. We included 274 patients in the analysis. With a median follow-up of 94 months for surviving patients, there was a trend for improved disease-free survival(DFS) in arm I compared with arm II, although it was not reached statistical significance (72% v. 63% at 7 years; P =.157). Especially, in patients who received abdominoperineal resection (APR), DFS was prolonged in arm I compared with arm II (66% v. 41% at 7 years; P=.033) Thirty six recurrences (26.7%) occurred in arm I and 49 (35.3%) in arm II (P =.151). Overall survival was not significantly different between arms I and II (71% v. 68% at 7 years; P =.855). Conclusions: With a long-term follow-up, this study failed to show a significant survival advantage for early radiotherapy with concurrent chemotherapy after resection of stage II and III rectal cancer. In patients with APR, significant improvement in DFS for arm I was observed.

No significant financial relationships to disclose.

Competing causes of death in NCIC CTG MA.17, a placebo-controlled trial of letrozole as extended adjuvant therapy for breast cancer patients

540

Background: Risk of death from other malignancies (OM) and other causes (OC) than breast cancer (BC) increases with age. Effects of baseline factors on type of death were assessed with competing risks analyses. Methods: In NCIC CTG MA.17, 5,187 women free of recurrent breast cancer after 5 years of tamoxifen were randomized to letrozole (L, 2,593 women) or placebo (P, 2,594 women). The primary endpoint was disease free survival (DFS), and secondary, overall survival (OS). Follow-up was to October 9, 2005: median 3.9 years, range <0.1 to 7.0 years. Effects of competing risks were examined for endpoints of BC, OM, and OC for 11 baseline trial factors: treatment, age, menopausal status, duration of prior tamoxifen, adjuvant radiotherapy, bone fracture, osteoporosis, cardiovascular disease, hormone receptor status, nodal status, adjuvant chemotherapy. Lagakos’ hierarchical method (Lagakos, Appl. Statist. 1978; 27:235–241) was used to test for differential effects of baseline factors on type of death (BC, OM, OC). Results: Rate of censoring was 97.8%, with 256 deaths (BC, 102; OM, 50; OC, 100; unknown, 4). Non-breast cancer deaths accounted for 60% of known deaths; 72%, for those ≥70 years; and 48%, for those <70 years. Two baseline factors differentially affected type of death. Women with cardiovascular disease were more likely to die from OC (p=0.02), while those with osteoporosis were more likely to die of OM (p=0.03). Age and nodal status had directionally similar effects. Older women had shorter survival from all 3 causes of death (p=0.01). Lymph node positivity was associated with worse survival (p=0.003). Conclusions: Extended L provides similar proportional benefit in improving DFS for all ages of women (Muss ref abstract SABCS 2006). However, the magnitude of competing non-breast cancer, and non-treatment related, causes of death needs to be considered more frequently, since with early detection and improved therapies, breast cancer patients may increasingly be expected to survive their disease to die from another cause. The novel association between baseline osteoporosis and other malignancies is being explored quantitatively.

No significant financial relationships to disclose.

Search for techniparticles in e+jets events at D0

We search for the technicolor process pp-->rhoT/omegaT-->WpiT in events containing one electron and two jets, in data corresponding to an integrated luminosity of 390 pb(-1), recorded by the D0 experiment at the Fermilab Tevatron. Technicolor predicts that technipions pi(T) decay dominantly into bb, bc, or bc, depending on their charge. In these events b and c quarks are identified by their secondary decay vertices within jets. Two analysis methods based on topological variables are presented. Since no excess above the standard model prediction was found, the result is presented as an exclusion in the pi(T) vs rho(T) mass plane for a given set of model parameters.