Adverse impact of a high CD4/CD8 ratio in the allograft may be overcome by methotrexate- but not mycophenolate- or posttransplant cyclophosphamide-based graft versus host disease prophylaxis

INTRODUCTION

A high CD4/CD8 T cell ratio in hematopoietic stem cell transplant (HSCT) allografts was observed to predict graft-versus-host disease (GVHD) and non-relapse mortality (NRM) but has not been comparatively examined in settings of various GVHD-prophylaxis regimens.

METHODS

This retrospective monocentric study included all consecutive HSCT performed with peripheral blood stem cells (PBSC) between January 2000 and June 2021. The impact of the graft CD4/CD8 ratio was analyzed in three cohorts with different GVHD-prophylaxis platforms.

RESULTS

In the cyclosporine/mycophenolate-mofetil (CSA/MMF) cohort (n = 294, HLA-matched HSCT), a high (> 75^th percentile) CD4/CD8 ratio was associated with increased overall mortality (HR 1.56; P=0.01), increased NRM (HR 1.85; P=0.01) and GVHD-associated mortality (HR 2.13; P=0.005). In the post-transplant cyclophosphamide (PTCy)/tacrolimus/MMF cohort (n = 113, haploidentical-related or mismatched-unrelated HSCT), a high CD4/CD8 ratio was associated with increased overall mortality (HR 2.07; P=0.04) and aGVHD3-4 (HR 2.24; P=0.02). By contrast, in the CSA/methotrexate (CSA/MTX) cohort (n = 185, HLA-matched HSCT) the CD4/CD8 ratio had no significant impact on any of the investigated endpoints.

CONCLUSION

A high CD4/CD8 ratio in the allograft has an adverse impact on GVHD and survival in CSA/MMF- and PTCy-based HSCT, while MTX-based prophylaxis may largely alleviate this important risk factor.

Pre-activated antiviral innate immunity in the upper airways controls early SARS-CoV-2 infection in children

Children have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and a substantially lower risk for developing severe coronavirus disease 2019 compared with adults. However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n = 18) and age-matched SARS-CoV-2-positive (n = 24) children and corresponding samples from adults (n = 44), covering an age range of 4 weeks to 77 years. Children displayed higher basal expression of relevant pattern recognition receptors such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than in adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)+ cytotoxic T cells and a CD8+ T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral response to SARS-CoV-2 infection than in adults.

101 Dothideomycetes genomes: A test case for predicting lifestyles and emergence of pathogens

Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species.

Behandlung der oberflächlichen Thrombophlebitis

Die oberflächliche Thrombophlebitis ist eine häufige Erkrankung, von der Frauen aufgrund ihrer Risikofaktoren stärker betroffen sind als Männer. Diagnostisch sollte eine eventuell gleichzeitig vorkommende tiefe Venenthrombose mit bildgebenden Verfahren abgegrenzt werden. In der Therapie sind Heparin bzw. niedermolekulare Heparine indiziert, wenn tiefe Venenthrombosen vorliegen bzw. ein Risiko hierfür besteht. Im akuten Stadium können nichtsteroidale Antiphlogistika oral genommen werden, um Schmerz und Entzündung zu lindern. Liegt gleichzeitig eine chronisch venöse Insuffizienz vor, unterstützen so genannte Ödemprotektiva (z.B. Rosskastaniensamenextrakt und flavonoidhaltige Präparate) die Behandlung.

Bei entzündlichen Veränderungen relativ kurzer oberflächlicher Venenabschnitte ohne Beteiligung des tiefen Venensystems ist die Beschränkung auf lokale Behandlungsmaßnahmen möglich. Neben der Kompressionstherapie sind mehrmalige tägliche Anwendungen heparin- und heparinoidhaltiger Salben bzw. Gele üblich.

Bewährt hat sich insbesondere die Anwendung von topischen Präparaten, die Mukopolysaccharidpolyschwefelsäureester (MPS) enthalten.

Die Problematik, die Wirksamkeit topischer Präparate bei der Behandlung der oberflächlichen Thrombophlebitis unter den gegenwärtig strengen Kautelen unserer Aufsichtsbehörde nachzuweisen und neue Produkte zu entwickeln, wird diskutiert.

Hypertrophic osteoarthropathy in a young adult male from Berber, Sudan (2nd-3rd century CE)

Hypertrophic osteoarthropathy (HOA) is a pathological condition characterised by extensive periosteal new bone formation (NBF) on the diaphyses of the long bones, metacarpal and metatarsal bones. In modern clinical contexts, the secondary form of the disease is common and most often occurs secondary to intra-thoracic cancer and other forms of chronic pulmonary disease. Paleopathological evidence for HOA on the other hand has only occasionally been reported. Here we report a young adult male from the Meriotic cemetery at Berber in Sudan (2nd-3rd century CE) displaying widespread NBF on the diaphyses of the upper and lower limb bones, metacarpal and metatarsal bones, as well as the pelvis and scapulae. While several pathological conditions have to be considered as differential diagnostic options for NBF in the post-cranial skeleton, HOA is the most likely diagnosis, based on the distribution of the changes observed in this individual, as well as their macroscopic and radiographic characteristics. A chronic pulmonary condition as indicated by NBF on the visceral side of the ribs may represent the underlying cause for the HOA. This individual represents the first paleopathological case of HOA reported from an archaeological site in Africa.

High-dose chemotherapy with autologous haematopoietic stem cell support for relapsed or refractory primary CNS lymphoma: a prospective multicentre trial by the German Cooperative PCNSL study group

To investigate safety and efficacy of high-dose chemotherapy followed by autologous stem cell transplantation (HCT-ASCT) in relapsed/refractory (r/r) primary central nervous system lymphoma (PCNSL), we conducted a single-arm multicentre study for immunocompetent patients (<66 years) with PCNSL failing high-dose methotrexate)-based chemotherapy. Induction consisted of two courses of rituximab (375 mg/m²), high-dose cytarabine (2 × 3 g/m²) and thiotepa (40 mg/m²) with collection of stem cells in between. Conditioning for HCT-ASCT consisted of rituximab 375 mg/m², carmustine 400 mg/m² and thiotepa (4 × 5 mg/kg). Patients commenced HCT-ASCT irrespective of response after induction. Patients not achieving complete remission (CR) after HCT-ASCT received whole-brain radiotherapy. Primary end point was CR after HCT-ASCT. We enrolled 39 patients; median age and Karnofsky performance score are 57 years and 90%, respectively. About 28 patients had relapsed and 8 refractory disease. About 22 patients responded to induction and 32 patients commenced HCT-ASCT. About 22 patients (56.4%) achieved CR after HCT-ASCT. Respective 2-year progression-free survival (PFS) and overall survival (OS) rates were 46.0% (median PFS 12.4 months) and 56.4%; median OS not reached. We recorded four treatment-related deaths. Thiotepa-based HCT-ASCT is an effective treatment option in eligible patients with r/r PCNSL. Comparative studies are needed to further scrutinise the role of HCT-ASCT in the salvage setting.

Oesophageal lichen planus: the efficacy of topical steroid-based therapies

BACKGROUND

Oesophageal lichen planus is an idiopathic inflammatory disorder characterized by significant oesophageal stricturing. Oesophageal lichen planus is a rare, difficult to diagnose, and likely an under recognized disease. As a result, there is no standardized approach to therapy and treatment strategies vary.

AIM

To examine the utility of topical steroid therapy (fluticasone or budesonide) in the management of oesophageal lichen planus.

METHODS

A retrospective chart review was conducted of patients diagnosed with oesophageal lichen planus who underwent baseline and follow up endoscopy pre and post topical steroid therapy between 1995 and 2016 at Mayo Clinic, Rochester MN. Average time between upper GI endoscopy was 3.2 months (0.7-11.7). Swallowed steroid preparations included fluticasone 880 μg twice daily or budesonide 3 mg twice daily. Patients were reviewed for symptomatic response to therapy using the Dakkak-Bennett dysphagia score (0-4, no dysphagia to total aphagia). Pre- and post-endoscopic findings were assessed. Additional baseline demographic, endoscopic, and histologic data were also obtained.

RESULTS

We identified 40 patients who met the inclusion criteria. A significant reduction in median dysphagia score from 1 (0-4) to 0 (0-3) after steroid therapy (P < 0.001) was noted. 62% of patients reported resolution of their dysphagia after receiving topical corticosteroids. 72.5% had an endoscopic response to steroid therapy.

CONCLUSION

Topical swallowed budesonide or fluticasone appear to effective treatment for oesophageal lichen planus.

fMRI Study of Sentence Generation by Early Bilinguals Differing in Proficiency Level

The aim of this study was to identify the functional anatomy of the cerebral speech regions involved in speaking in native and foreign language in the same subject using functional magnetic resonance imaging.

Experimental design consisted of two activation runs. Each of them included two kinds of tasks arranged in series of five blocks lasting for 30s. In the experimental condition of the first run subjects were required to speak in their native language and in the second run the task was to speak in the foreign language. In both runs, baseline condition was the same and subjects were supposed to lie silently inside the bore. We observed the influence of proficiency on brain activation. In subjects with equal proficiency in the first and the second language, differences were not observed. In the subjects with unequal proficiency in the first and the second language we observed two main effects.

First was difference in the strength and extension of activation, the second effect was activation of new regions for the second language, in which proficiency was lower.

Environmental impact of using specialty feed ingredients in swine and poultry production: A life cycle assessment

Livestock production has a variety of environmental impacts such as greenhouse gas emissions, water pollution, acidification, and primary energy consumption. The demand for livestock products is expected to grow substantially, creating even more environmental pressure. The use of specialty feed ingredients (SFI) such as supplemented AA and phytase can reduce nutrient input into the system without compromising productivity and consequently can reduce emissions. The global change impact of using SFI in pig and broiler production systems in Europe and North and South America was studied. A life cycle assessment according to international standards (ISO 14040/44) analyzed contributions from producing SFI and animals to global change. Three different alternatives were analyzed. In addition, partial sensitivity analysis was conducted using 5 scenarios for each region for both production systems. Specialty feed ingredient supplementation in pig and broiler diets reduced greenhouse gas emissions (cradle to farm gate) by 56% and 54% in Europe, 17% and 15% in North America, and 33% and 19% in South America, respectively, compared to an unsupplemented diet. A total of 136 Mt CO equivalent (CO eq) was saved in 2012, rising to 146 Mt CO eq in 2050 on the basis of United Nations population projections. Considerable benefits of supplementation with SFI were apparent in European and South American diets when direct land use change was considered because of the reduced demand for soybean meal. The eutrophication potential of unsupplemented diets was reduced by up to 35% in pig and 49% in broiler production systems compared to supplemented alternatives. The acidification potential of supplemented strategies was reduced by up to 30% in pig and 79% in broiler production systems. The primary energy demand was similar in all alternatives, and this could be an area where the SFI industry can improve. Overall, SFI supplementation substantially reduced the global warming, eutrophication, and acidification potentials in all regions studied.

Pharmacological insight into the anti-inflammatory activity of sesquiterpene lactones from Neurolaena lobata (L.) R.Br. ex Cass

PURPOSE

Neurolaena lobata is a Caribbean medicinal plant used for the treatment of several conditions including inflammation. Recent data regarding potent anti-inflammatory activity of the plant and isolated sesquiterpene lactones raised our interest in further pharmacological studies. The present work aimed at providing a mechanistic insight into the anti-inflammatory activity of N. lobata and eight isolated sesquiterpene lactones, as well as a structure-activity relationship and in vivo anti-inflammatory data.

METHODS

The effect of the extract and its compounds on the generation of pro-inflammatory proteins was assessed in vitro in endothelial and monocytic cells by enzyme-linked immunosorbent assay. Their potential to modulate the expression of inflammatory genes was further studied at the mRNA level. In vivo anti-inflammatory activity of the chemically characterized extract was evaluated using carrageenan-induced paw edema model in rats.

RESULTS

The compounds and extract inhibited LPS- and TNF-α-induced upregulation of the pro-inflammatory molecules E-selectin and interleukin-8 in HUVECtert and THP-1 cells. LPS-induced elevation of mRNA encoding for E-selectin and interleukin-8 was also suppressed. Furthermore, the extract inhibited the development of acute inflammation in rats.

CONCLUSIONS

Sesquiterpene lactones from N. lobata interfered with the induction of inflammatory cell adhesion molecules and chemokines in cells stimulated with bacterial products and cytokines. Structure-activity analysis revealed the importance of the double bond at C-4-C-5 and C-2-C-3 and the acetyl group at C-9 for the anti-inflammatory activity. The effect was confirmed in vivo, which raises further interest in the therapeutic potential of the compounds for the treatment of inflammatory diseases.

Role of Growth arrest-specific gene 6-Mer axis in multiple myeloma

Multiple myeloma is a mostly incurable malignancy characterized by the expansion of a malignant plasma cell (PC) clone in the human bone marrow (BM). Myeloma cells closely interact with the BM stroma, which secretes soluble factors that foster myeloma progression and therapy resistance. Growth arrest-specific gene 6 (Gas6) is produced by BM-derived stroma cells and can promote malignancy. However, the role of Gas6 and its receptors Axl, Tyro3 and Mer (TAM receptors) in myeloma is unknown. We therefore investigated their expression in myeloma cell lines and in the BM of myeloma patients and healthy donors. Gas6 showed increased expression in sorted BMPCs of myeloma patients compared with healthy controls. The fraction of Mer(+) BMPCs was increased in myeloma patients in comparison with healthy controls whereas Axl and Tyro3 were not expressed by BMPCs in the majority of patients. Downregulation of Gas6 and Mer inhibited the proliferation of different myeloma cell lines, whereas knocking down Axl or Tyro3 had no effect. Inhibition of the Gas6 receptor Mer or therapeutic targeting of Gas6 by warfarin reduced myeloma burden and improved survival in a systemic model of myeloma. Thus, the Gas6-Mer axis represents a novel candidate for therapeutic intervention in this incurable malignancy.

Resilience in patients and spouses faced with malignant melanoma. A qualitative longitudinal study

Life-threatening diseases like malignant tumours are associated with considerable existential distress. Little is known about the factors that promote resilience within these individuals. This longitudinal qualitative partner study aimed to analyse resilience as per Antonovsky's sense of coherence. Eight patients with malignant melanoma and their partners were interviewed. They were asked about their coping strategies, attitudes towards the meaning of life and their cancer, and comprehension of what is happening to them. The questions were asked shortly after their diagnosis was made and 6 months later. All interviews were audio-taped and later transcribed and analysed according to the method of qualitative content analysis described by P. Mayring. At baseline, the majority of statements made (261; patients = 141/spouses = 120) related to coping/manageability of disease, with only 26 statements (patients = 15/spouses = 11) related to meaning and 127 (patients = 64/spouses = 63) to comprehension. There were no significant differences between the responses of patients and their partners and no significant changes in the number of statements during the 6-month interview. The most significant theme that emerged was manageability of disease, with distraction the most commonly utilised coping skill. The comprehension and meaning themes were far less prevalent. Hence, support should focus on disease and situational manageability.

Alternaria redefined

Alternaria is a ubiquitous fungal genus that includes saprobic, endophytic and pathogenic species associated with a wide variety of substrates. In recent years, DNA-based studies revealed multiple non-monophyletic genera within the Alternaria complex, and Alternaria species clades that do not always correlate to species-groups based on morphological characteristics. The Alternaria complex currently comprises nine genera and eight Alternaria sections. The aim of this study was to delineate phylogenetic lineages within Alternaria and allied genera based on nucleotide sequence data of parts of the 18S nrDNA, 28S nrDNA, ITS, GAPDH, RPB2 and TEF1-alpha gene regions. Our data reveal a Pleospora/Stemphylium clade sister to Embellisia annulata, and a well-supported Alternaria clade. The Alternaria clade contains 24 internal clades and six monotypic lineages, the assemblage of which we recognise as Alternaria. This puts the genera Allewia, Brachycladium, Chalastospora, Chmelia, Crivellia, Embellisia, Lewia, Nimbya, Sinomyces, Teretispora, Ulocladium, Undifilum and Ybotromyces in synonymy with Alternaria. In this study, we treat the 24 internal clades in the Alternaria complex as sections, which is a continuation of a recent proposal for the taxonomic treatment of lineages in Alternaria. Embellisia annulata is synonymised with Dendryphiella salina, and together with Dendryphiella arenariae, are placed in the new genus Paradendryphiella. The sexual genera Clathrospora and Comoclathris, which were previously associated with Alternaria, cluster within the Pleosporaceae, outside Alternaria s. str., whereas Alternariaster, a genus formerly seen as part of Alternaria, clusters within the Leptosphaeriaceae. Paradendryphiella is newly described, the generic circumscription of Alternaria is emended, and 32 new combinations and 10 new names are proposed. A further 10 names are resurrected, while descriptions are provided for 16 new Alternaria sections.

Electrophysiological correlates of attentional processes in patients with liver cirrhosis without minimal or clinically-overt hepatic encephalopathy

Liver cirrhosis is often accompanied by a spectrum of cognitive deficits, labelled hepatic encephalopathy (HE). The precise specification of cognitive impairment associated with HE has not been yet elucidated. The aim of this study was an attempt to examine cortical function in cirrhotic patients using EEG event-related potentials during a demanding task involving selective attention. We compared group of 30 patients with liver cirrhosis without minimal or overt HE with education-, age- and sex-matched 29 non-cirrhotic controls. Both groups performed an attentional blink (AB) task, which requires detecting and identifying two target characters in a longer series of rapidly and sequentially presented characters. EEG signals from 32 electrodes were measured and then analyzed in the paradigm of event-related potentials (ERP). Though the groups did not differ in the detection rate of the target stimuli, ERP waveforms revealed two group differences of component amplitudes. The first difference was related to the waveform amplitude within the 200-400 ms after first target in the right frontal region (frontocentral N2 component). Moreover, in patient group this amplitude positively correlated with the blood plasma level of alkaline phosphatase and gamma-glutamyl transpeptidase. The second amplitude difference was observed in the midline parieto-occipital regions within the 400-600 ms after the first target (P3b component). The AB task and ERP analysis allowed to find differences in cortical functioning in cirrhotic patients even without overt cognitive deficits. Our finding demonstrates that liver dysfunction can influence cortical processing associated with detecting and categorizing stimulus change.

Cognitive evoked response potentials in patients with liver cirrhosis without diagnosis of minimal or overt hepatic encephalopathy. A pilot study

Liver cirrhosis is often accompanied by cognitive deficits called minimal hepatic encephalopathy (MHE) when it is observed to a moderate extent. In the present study, brain activity and cognitive functioning were examined in patients with liver cirrhosis without MHE or overt clinical hepatic encephalopathy. A battery of neuropsychological tests and event related potentials (ERPs) were used. Moreover, an additional n-back task was administered with two difficulty levels (1- and 2-back). This task was designed to engage cognitive processes of storage and manipulation of information in working memory. The participants have to decide whether the letter shown was the same as a target (congruence condition). No significant differences were found in the performance of either the neuropsychological tests or the n-back task. However, the expected effects of decreased performance as well as a decrease in P3 amplitude with difficulty level were identified. The interaction of group x congruence condition was also observed in the P2 component time window. These results may indicate group differences manifesting in early stages of information processing in working memory. It confirms that the patients whose neuropsychological performance is within the normal range can still reveal subtle changes in CNS functioning visible in ERP research. The study confirms the usability of the ERP method in diagnosis of neurocognitive functions in patients with liver cirrhosis, which seems to be more sensitive than neuropsychological tests.

Rituximab monotherapy for primary cutaneous B-cell lymphoma: response and follow-up in 16 patients

BACKGROUND

We have carried out a retrospective analysis to evaluate the therapeutic value of the anti-CD20 antibody rituximab in 16 consecutive patients with primary cutaneous CD20+ B-cell lymphomas.

PATIENTS AND METHODS

Sixteen patients (4 females, 12 males) with a median age of 54 years received systemic therapy with rituximab 375 mg/m(2) once weekly for four or six consecutive weeks. Eleven patients had primary cutaneous follicle center cell lymphoma and five patients had a primary cutaneous marginal zone B-cell lymphoma.

RESULTS

Of the 16 patients with PCBCL, 14 patients (87.5%) achieved complete remission (CR). In two patients, partial remission was obtained and additional focal radiotherapy was applied, which resulted in final CR. Five to 14 (35%) patients with CR relapsed, in an interval between 6 and 37 months. There were no severe side-effects.

CONCLUSIONS

On the basis of our results, single-agent treatment with i.v. rituximab appears to be feasible and safe and results in a high rate of durable remissions. Judging from our data, it appears to be an attractive treatment option and should be directly compared with local radiotherapy.

[An unusual cause of severe abdominal pain]

A 33-year-old previously healthy man was admitted to the hospital with a 6-day history of diffuse abdominal pain and constipation. He was afebrile, looked unwell with a pale skin and displayed an elevated blood pressure. He had no peritoneal sign, and bowel sounds were normal. Blood tests were remarkable for a hematocrit of 26 % and mean cell volume of 83 fl, bilirubin levels were slightly elevated. Abdominal radiographs, abdominal ultrasound and computed tomography showed stool throughout the colon with a non-specific bowel gas pattern. Moreover, colonoscopy and gastroscopy provided no information on the underlying cause of the patient's severe pain. He was treated with fluids and spasmolytic drugs until the result of the urinary porphyrin level was received, which showed an elevated concentration of 1608 microg/d. Consequently, the plasma lead concentration was determined showing an elevated level of 92.3 microg/d. The examination of blood slides revealed erythrocytes with basophile stippling. On physical examination, a bluish discoloration could be seen along the gums. After starting the detoxication therapy with DMPS - 1800 mg p. o. for the first two days followed by 600 mg DMPS daily - the complaints disappeared. In spite of an extensive anamnestic exploration the source of the lead intoxication could not be found until now.

Study of the decay Bs(0)-->Ds(*)Ds(*)

We report a study of the decay Bs(0)-->Ds(*)Ds(*) using a data sample corresponding to 1.3 fb(-1) of integrated luminosity collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. One Ds(*) meson was partially reconstructed in the decay Ds-->phi mu nu, and the other Ds(*) meson was identified using the decay Ds-->phi pi where no attempt was made to distinguish Ds and Ds(*) states. For the branching fraction Br(Bs(0)-->Ds(*)Ds(*)) we obtain a 90% C.L. range [0.002,0.080] and central value 0.039(-0.017)(+0.019)(stat)(-0.015)(+0.016)(syst). This was subsequently used to make the most precise estimate of the width difference DeltaGamma(s)CP in the Bs(0)-Bs(0) system: DeltaGamma(s)CP/Gamma(s)=0.079(-0.035)(+0.038)(stat)(-0.030)(+0.031)(syst).

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.

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.

Evidence for production of single top quarks and first direct measurement of |Vtb|

The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron pp[over ] collider. Using a 0.9 fb(-1) dataset, we apply a multivariate analysis to separate signal from background and measure sigma(pp[over ]-->tb+X,tqb+X)=4.9+/-1.4 pb. The probability to measure a cross section at this value or higher in the absence of a signal is 0.035%, corresponding to a 3.4 standard deviation significance. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa matrix element that describes the Wtb coupling and find 0.68<|V(tb)|</=1 at 95% C.L. within the standard model.

Measurement of the charge asymmetry in semileptonic Bs0 decays

We have performed the first direct measurement of the time-integrated flavor untagged charge asymmetry in semileptonic Bs0 decays ASLs,unt by comparing the decay rate of Bs0-->micro+Ds-nuX, where Ds- -->phipi- and phi-->K+K-, with the charge-conjugate Bs0 decay rate. This sample was selected from 1.3 fb-1 of data collected by the D0 experiment in run II of the Fermilab Tevatron collider. We obtain ASLs,unt=[1.23+/-0.97(stat)+/-0.17(syst)]x10(-2). Assuming that Deltam(s)/Gamma(s)>>1, this result can be translated into a measurement of the CP-violating phase in Bs0 mixing: DeltaGamma(s)/Deltam(s)tanphi(s)=[2.45+/-1.93(stat)+/-0.35(syst)]x10(-2).

Lifetime difference and CP-violating phase in the Bs0 system

From an analysis of the decay Bs0-->J/psi phi, we obtain the width difference between the light and heavy mass eigenstates DeltaGamma identical with (GammaL-GammaH)=0.17+/-0.09(stat)+/-0.02(syst) ps-1 and the CP-violating phase phis=-0.79+/-0.56(stat)(-0.01)(+0.14)(syst). Under the hypothesis of no CP violation (phis identical with 0), we obtain 1/Gamma=tau(Bs0)=1.52+/-0.08(stat)(-0.03)(+0.01)(syst) ps and DeltaGamma=0.12(-0.10)(+0.08)(stat)+/-0.02(syst) ps-1. The data sample corresponds to an integrated luminosity of about 1.1 fb-1 accumulated with the D0 detector at the Fermilab Tevatron collider. This is the first direct measurement of the CP-violating mixing phase in the Bs0 system.

Prediction of non-sentinel node status and outcome in sentinel node-positive melanoma patients

AIMS

Sentinel lymph node (SLN) -positive melanoma patients are usually recommended completion lymph node dissection (CLND) with the aim to provide regional disease control and improve survival. Nevertheless, only 20% these patients have additional metastases in non-sentinel lymph nodes (NSLN), indicating that CLND may be unnecessary in the majority of patients. In this retrospective study, we (i) sought to identify clinico-pathological features predicting NSLN status, as well as disease-free (DFS) and -specific (DSS) survival and (ii) evaluated the applicability of previously published algorithms, which were able to define a group of patients at zero-risk for NSLN-metastasis.

METHODS

This analysis included 504 consecutive melanoma patients stage I and II who underwent successful SLN-biopsy (SLNB) at our institute between 1998 and 2005. Metastatic SLN were re-evaluated for tumor burden and categorized according to two different micro-anatomic classifications and the S/U-score (Size of the sentinel node metastasis > 2 mm/Ulceration of the primary melanoma) was assessed. DFS and DSS were calculated for all analyses.

RESULTS

Out of 504 melanoma patients stage I or II, 85 (17%) were SLN-positive and 18 of 85 (21%) were found with positive NSLN in the CLND specimen. Median follow-up was 31 months. Neither primary tumor characteristics (age, gender, Clark level, Breslow thickness, ulceration of the primary melanoma, site and histological subtype of the primary melanoma), nor features of the sentinel node tumor (number and site of draining lymph node basins, number of positive sentinel nodes and size of sentinel node tumor (< 2 mm vs. > or = 2 mm) were able to predict additional positive lymph nodes in the CLND specimen. Likewise the implementation of published algorithms was not able to identify patients at negligible risk for harboring NSLN metastases. Upon univariate analysis, disease-free survival in SLN-positive patients was correlated with Breslow thickness, sentinel node tumor size > 2 mm and S/U score. In respect to disease-specific survival the significant prognostic parameters were Breslow thickness, ulceration, sentinel node tumor size > 2 mm and the S/U score. After a median follow-up of 31 months recurrence rates (37% vs. 78%, p=0.02) and death from disease (24% vs. 50%, p<0.01) were significantly different in patients with SLN-metastasis only as compared to patients with NSLN-metastasis.

CONCLUSION

NSLN status cannot be predicted in this data analysis by using clinico-pathological characteristics. Therefore, CLND is recommended for all patients after positive SLNB pending the results of the second Multicenter Selective Lymphadenectomy Trial.

Experimental discrimination between charge 2e/3 top quark and charge 4e/3 exotic quark production scenarios

We present the first experimental discrimination between the 2e/3 and 4e/3 top quark electric charge scenarios, using top quark pairs (tt) produced in pp collisions at (square root) s = 1.96 TeV by the Fermilab Tevatron Collider. We use 370 pb;{-1} of data collected by the D0 experiment and select events with at least one high transverse momentum electron or muon, high transverse energy imbalance, and four or more jets. We discriminate between b- and b-quark jets by using the charge and momenta of tracks within the jet cones. The data are consistent with the expected electric charge, |q|=2e/3. We exclude, at the 92% C.L., that the sample is solely due to the production of exotic quark pairs QQ with |q|=4e/3. We place an upper limit on the fraction of QQ pairs rho<0.80 at the 90% C.L.

Measurement of the Bs(0) lifetime using semileptonic decays

We report a measurement of the Bs(0) lifetime in the semileptonic decay channel Bs(0) --> Ds- mu+ nuX (and its charge conjugate), using approximately 0.4 fb(-1) of data collected with the D0 detector during 2002-2004. Using 5176 reconstructed Ds- mu+ signal events, we have measured the Bs(0) lifetime to be tau(Bs(0))=1.398+/-0.044(stat)(-0.025)(+0.028)(syst) ps. This is the most precise measurement of the Bs(0) lifetime to date.

Search for pair production of scalar bottom quarks in pp collisions at square root of s = 1.96 TeV

A search for direct production of scalar bottom quarks (b) is performed with 310 pb(-1) of data collected by the D0 experiment in pp collisions at square root s = 1.96 TeV at the Fermilab Tevatron Collider. The topology analyzed consists of two b jets and an imbalance in transverse momentum due to undetected neutralinos (chi(1)0), with chi(1)0 assumed to be the lightest supersymmetric particle. We find the data consistent with standard model expectations, and set a 95% C.L. exclusion domain in the (m(b), m(chi(1)0)) mass plane, improving significantly upon the results from run I of the Tevatron.

Search for neutral, long-lived particles decaying into two muons in pp[over] collisions at sqrt[s]=1.96 TeV

We present a search for a neutral particle, pair produced in pp[over] collisions at sqrt[s]=1.96 TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis uses approximately 380 pb(-1) of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4x10(-11) s, we exclude values greater than 0.14 pb (95% C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events.

Search for the standard model Higgs Boson in the pp[over]-->ZH-->nunu[over]bb[over] channel

We report a search for the standard model (SM) Higgs boson based on data collected by the D0 experiment at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 260 pb(-1). We study events with missing transverse energy and two acoplanar b jets, which provide sensitivity to the ZH production cross section in the nunu[over]bb[over] channel, and to WH production when the lepton from the W-->lnu decay is undetected. The data are consistent with the SM background expectation, and we set 95% C.L. upper limits on sigma(pp[over]-->ZH/WH)xB(H-->bb[over]) from 3.4/8.3 to 2.5/6.3 pb, for Higgs-boson masses between 105 and 135 GeV.

Search for associated higgs boson production WH-->WWW*-->l+/-nul'+/-nu'+X in pp collisions at square root s=1.96 Te V

We present a search for associated Higgs boson production in the process pp-->WH-->WWW*-->l;+/-nul'+/-nu'+X in final states containing two like-sign isolated electrons or muons (e+/-e;+/-, e+/-micro+/-, or micro+/-micro+/-). The search is based on D0 run II data samples corresponding to integrated luminosities of 360-380 pb-1. No excess is observed over the predicted standard model background. We set 95% C.L. upper limits on sigma(pp-->WH)xBr(H-->WW*) between 3.2 and 2.8 pb for Higgs boson masses from 115 to 175 GeV.

Search for neutral Higgs bosons decaying to tau pairs in pp[over ] collisions at sqrt[s]=1.96 TeV

A search for the production of neutral Higgs bosons Phi decaying into tau(+)tau(-) final states in pp[over ] collisions at a center-of-mass energy of 1.96 TeV is presented. The data, corresponding to an integrated luminosity of approximately 325 pb(-1), were collected by the D0 experiment at the Fermilab Tevatron Collider. Since no excess compared to the expectation from standard model processes is found, limits on the production cross section times branching ratio are set. The results are combined with those obtained from the D0 search for Phib(b[over ])-->bb[over ]b(b[over ]) and are interpreted in the minimal supersymmetric standard model.

Search for resonant second generation slepton production at the Fermilab Tevatron

We present a search for supersymmetry in the R-parity violating resonant production and decay of smuons and muon sneutrinos in the channels mu-->chi(1)(0)mu, mu-->chi(2,3,4)(0)mu, and nu(mu)-->chi(1,2)(+/-)mu. We analyzed 0.38 fb(-1) of integrated luminosity collected between April 2002 and August 2004 with the D0 detector at the Fermilab Tevatron Collider. The observed number of events is in agreement with the standard model expectation, and we calculate 95% C.L. limits on the slepton production cross section times branching fraction to gaugino plus muon, as a function of slepton and gaugino masses. In the framework of minimal supergravity, we set limits on the coupling parameter lambda(211)('), extending significantly previous results obtained in Run I of the Tevatron and at the CERN LEP collider.

Direct limits on the oscillation frequency

We report results of a study of the B(s)(0) oscillation frequency using a large sample of B(s)(0) semileptonic decays corresponding to approximately 1 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider in 2002-2006. The amplitude method gives a lower limit on the B(s)(0) oscillation frequency at 14.8 ps(-1) at the 95% C.L. At delta m(s) = 19 ps(-1), the amplitude deviates from the hypothesis A= 0(1) by 2.5 (1.6) standard deviations, corresponding to a two-sided C.L. of 1% (10%). A likelihood scan over the oscillation frequency, delta m(s), gives a most probable value of 19 ps(-1) and a range of 17 < delta m(s) < 21 ps(-1)at the 90% C.L., assuming Gaussian uncertainties. This is the first direct two-sided bound measured by a single experiment. If delta m(s) lies above 22 ps(-1), then the probability that it would produce a likelihood minimum similar to the one observed in the interval 16-22 ps(-1) is (5.0 +/- 0.3)%.