520 research outputs found

    Groupoids and an index theorem for conical pseudo-manifolds

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    We define an analytical index map and a topological index map for conical pseudomanifolds. These constructions generalize the analogous constructions used by Atiyah and Singer in the proof of their topological index theorem for a smooth, compact manifold MM. A main ingredient is a non-commutative algebra that plays in our setting the role of C0(T∗M)C_0(T^*M). We prove a Thom isomorphism between non-commutative algebras which gives a new example of wrong way functoriality in KK-theory. We then give a new proof of the Atiyah-Singer index theorem using deformation groupoids and show how it generalizes to conical pseudomanifolds. We thus prove a topological index theorem for conical pseudomanifolds

    Improper colourings inspired by Hadwiger’s conjecture

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    Hadwiger’s Conjecture asserts that every Kt-minor-free graph has a proper (t − 1)-colouring. We relax the conclusion in Hadwiger’s Conjecture via improper colourings. We prove that every Kt-minor-free graph is (2t − 2)-colourable with monochromatic components of order at most 1/2 (t − 2). This result has no more colours and much smaller monochromatic components than all previous results in this direction. We then prove that every Kt-minor-free graph is (t − 1)-colourable with monochromatic degree at most t − 2. This is the best known degree bound for such a result. Both these theorems are based on a decomposition method of independent interest. We give analogous results for Ks,t-minorfree graphs, which lead to improved bounds on generalised colouring numbers for these classes. Finally, we prove that graphs containing no Kt-immersion are 2-colourable with bounded monochromatic degree

    A cohomological formula for the Atiyah-Patodi-Singer index on manifolds with boundary

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    International audienceWe give a cohomological formula for the index of a fully elliptic pseudodifferential operator on a manifold with boundary. As in the classic case of Atiyah-Singer, we use an embedding into an euclidean space to express the index as the integral of a cohomology class depending in this case on a noncommutative symbol, the integral being over a C∞C^\infty-manifold called the singular normal bundle associated to the embedding. The formula is based on a K-theoretical Atiyah-Patodi-Singer theorem for manifolds with boundary that is drawn from Connes' tangent groupoid approach

    Impact of the COVID-19 pandemic on the care of cancer patients in Spain

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    Background: Studies evaluating the effects of the COVID-19 pandemic on public healthcare systems are limited, particularly in cancer management. As no such studies have been carried out in Spain, our objective is to describe and quantify the impact of the COVID-19 pandemic on cancer patients in Spanish hospitals during the first wave of the pandemic. Materials and methods: This retrospective, multicenter, nationwide study collected information from hospital departments treating oncology patients. An electronic questionnaire comparing outcomes and management of oncohematological patients for the March-June 2019 and March-June 2020 periods was used. Results: Information from 78 departments (36 tertiary hospitals) was analyzed. Forty-four departments implemented adapted protocols during March 2020. Most of these (n = 38/44; 86.4%) carried out COVID-19 triage, while 26 of 44 (59.1%) carried out onsite polymerase chain reaction tests for clinically suspected cases. A shift from in-person to telephone visits was observed in 43 of 44 (97.7%) departments. Comparing the March-June 2019 and March-June 2020 periods, the number of new patients decreased by 20.8% (from 160.2 to 126.4). Decreases were also seen in the mean number of total (2858.2 versus 1686.1) and cancer (465.5 versus 367.2) biopsies, as well as the mean number of bone marrow biopsies (30.5 versus 18.6). Concerning the number of patients visiting specific cancer care departments, a decrease from 2019 to 2020 was seen for mean number of chemotherapy treatments (712.7 versus 643.8) and radiation therapy (2169.9 versus 2139.9). Finally, a reduction from 2019 to 2020 of 12.9% (from 8.6 to 7.4) in the mean number of patients included in clinical trials was noted. Conclusions: This study provides the first comprehensive data concerning the impact of COVID-19 on cancer care in Spain. The pandemic caused a 20.8% decrease in newly diagnosed patients, which may impact future outcomes. Measures must be taken to ensure cancer management receives priority in times of healthcare emergencies

    A snapshot of cancer-associated thromboembolic disease in 2018-2019: First data from the TESEO prospective registry

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    BACKGROUND: The ever-growing complexity of cancer-associated thrombosis (CAT), with new antineoplastic drugs and anticoagulants, distinctive characteristics, and decisions with low levels of evidence, justifies this registry. METHOD: TESEO is a prospective registry promoted by the Spanish Society of Medical Oncology to which 34 centers contribute cases. It seeks to provide an epidemiological description of CAT in Spain. RESULTS: Participants (N=939) with CAT diagnosed between July 2018 and December 2019 were recruited. Most subjects had advanced colon (21.4%), non-small cell lung (19.2%), and breast (11.1%) cancers, treated with dual-agent chemotherapy (28.4%), monochemotherapy (14.4%), or immune checkpoint inhibitors (3.6%). Half (51%) were unsuspected events, albeit only 57.1% were truly asymptomatic. Pulmonary embolism (PE) was recorded in 571 (58.3%); in 120/571 (21.0%), there was a concurrent deep venous thromboembolism (VTE). Most initially received low molecular weight heparin (89.7%). Suspected and unsuspected VTE had an OS rate of 9.9 (95% CI, 7.3-non-computable) and 14.4 months (95% CI, 12.6-non-computable) (p=0.00038). Six-month survival was 80.9%, 55.9%, and 55.5% for unsuspected PE, unsuspected PE admitted for another reason, and suspected PE, respectively (p<0.0001). The 12-month cumulative incidence of venous rethrombosis was 7.1% (95% CI, 4.7-10.2) in stage IV vs 3.0% (95% CI, 0.9-7.1) in stages I-III. The 12-month cumulative incidence of major/clinically relevant bleeding was 9.6% (95% CI, 6.1-14.0) in the presence of risk factors. CONCLUSION: CAT continues to be a relevant problem in the era of immunotherapy and targeted therapies. The initial TESEO data highlight the evolution of CAT, with new agents and thrombotic risk factors

    Understanding the importance of selenium and selenoproteins in muscle function

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    Selenium is an essential trace element. In cattle, selenium deficiency causes dysfunction of various organs, including skeletal and cardiac muscles. In humans as well, lack of selenium is associated with many disorders, but despite accumulation of clinical reports, muscle diseases are not generally considered on the list. The goal of this review is to establish the connection between clinical observations and the most recent advances obtained in selenium biology. Recent results about a possible role of selenium-containing proteins in muscle formation and repair have been collected. Selenoprotein N is the first selenoprotein linked to genetic disorders consisting of different forms of congenital muscular dystrophies. Understanding the muscle disorders associated with selenium deficiency or selenoprotein N dysfunction is an essential step in defining the causes of the disease and obtaining a better comprehension of the mechanisms involved in muscle formation and maintenance

    Future care for long-term cancer survivors: towards a new model

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    Purpose: The increase in the prevalence "long-term cancer survivor” (LCS) patients is expected to increase the cost of LCS care. The aim of this study was to obtain information that would allow to optimise the current model of health management in Spain to adapt it to one of efficient LCS patient care. Methods: This qualitative study was carried out using Delphi methodology. An advisory committee defined the criteria for participation, select the panel of experts, prepare the questionnaire, interpret the results and draft the final report. Results: 232 people took part in the study (48 oncologists). Absolute consensus was reached in three of the proposed sections: oncological epidemiology, training of health professionals and ICT functions. Conclusion: The role of primary care in the clinical management of LCS patients needs to be upgraded, coordination with the oncologist and hospital care is essential. The funding model needs to be adapted to determine the funding conditions for new drugs and technologiesOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This project was funded by AZ. The funding party did not influence the opinion of the authors. All the authors have accepted the participation as advisers of the ASISTO group and give their consent for the publication of the documen

    A retrospective, multicenter study of the efficacy of lapatinib plus trastuzumab in HER2-positive metastatic breast cancer patients previously treated with trastuzumab, lapatinib, or both: the Trastyvere study

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    [Purpose]: To evaluate the efficacy and safety of lapatinib (L) and trastuzumab (T) combination in HER2-positive metastatic breast cancer (MBC) patients previously treated with T and/or L.[Materials and methods]: We conducted a retrospective, post-authorized, multicenter study including patients with HER2-positive MBC or locally advanced breast cancer (ABC) treated with the combination of L–T. Concomitant endocrine therapy, as well as brain metastasis and/or prior exposure to L, were allowed.[Results]: One hundred and fifteen patients from 14 institutions were included. The median age was 59.8 years. The median number of prior T regimens in the advanced setting was 3 and 73 patients had received a prior L regimen. The clinical benefit rate (CBR) was 34.8% (95% CI 26.1–43.5). Among other efficacy endpoints, the overall response rate was 21.7%, and median progression-free survival (PFS) and overall survival were 3.9 and 21.6 months, respectively. Heavily pretreated and ≄ 3 metastatic organ patients showed lower CBR and PFS than patients with a low number of previous regimens and < 3 metastatic organs. Moreover, CBR did not significantly change in L-pretreated compared with L-naĂŻve patients (31.5% versus 40.5% for L-pretreated versus L-naĂŻve). Grade 3/4 adverse events were reported in 19 patients (16.5%).[Conclusion]: The combination of L–T is an effective and well-tolerated regimen in heavily pretreated patients and remains active among patients progressing on prior L-based therapy. Our study suggests that the L–T regimen is a safe and active chemotherapy-free option for MBC patients previously treated with T and/or L.This work was supported by GlaxoSmithKline plc (GSK) through a contract with Medica Scientia Innovation Research (MedSIR), an academic research organization focused on independent clinical research development

    Selenoprotein gene nomenclature

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    The human genome contains 25 genes coding for selenocysteine-containing proteins (selenoproteins). These proteins are involved in a variety of functions, most notably redox homeostasis. Selenoprotein enzymes with known functions are designated according to these functions: TXNRD1, TXNRD2, and TXNRD3 (thioredoxin reductases), GPX1, GPX2, GPX3, GPX4 and GPX6 (glutathione peroxidases), DIO1, DIO2, and DIO3 (iodothyronine deiodinases), MSRB1 (methionine-R-sulfoxide reductase 1) and SEPHS2 (selenophosphate synthetase 2). Selenoproteins without known functions have traditionally been denoted by SEL or SEP symbols. However, these symbols are sometimes ambiguous and conflict with the approved nomenclature for several other genes. Therefore, there is a need to implement a rational and coherent nomenclature system for selenoprotein-encoding genes. Our solution is to use the root symbol SELENO followed by a letter. This nomenclature applies to SELENOF (selenoprotein F, the 15 kDa selenoprotein, SEP15), SELENOH (selenoprotein H, SELH, C11orf31), SELENOI (selenoprotein I, SELI, EPT1), SELENOK (selenoprotein K, SELK), SELENOM (selenoprotein M, SELM), SELENON (selenoprotein N, SEPN1, SELN), SELENOO (selenoprotein O, SELO), SELENOP (selenoprotein P, SeP, SEPP1, SELP), SELENOS (selenoprotein S, SELS, SEPS1, VIMP), SELENOT (selenoprotein T, SELT), SELENOV (selenoprotein V, SELV) and SELENOW (selenoprotein W, SELW, SEPW1). This system, approved by the HUGO Gene Nomenclature Committee, also resolves conflicting, missing and ambiguous designations for selenoprotein genes and is applicable to selenoproteins across vertebrates
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