136 research outputs found

    The Minimal Length of a Lagrangian Cobordism between Legendrians

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    To investigate the rigidity and flexibility of Lagrangian cobordisms between Legendrian submanifolds, we investigate the minimal length of such a cobordism, which is a 11-dimensional measurement of the non-cylindrical portion of the cobordism. Our primary tool is a set of real-valued capacities for a Legendrian submanifold, which are derived from a filtered version of Legendrian Contact Homology. Relationships between capacities of Legendrians at the ends of a Lagrangian cobordism yield lower bounds on the length of the cobordism. We apply the capacities to Lagrangian cobordisms realizing vertical dilations (which may be arbitrarily short) and contractions (whose lengths are bounded below). We also study the interaction between length and the linking of multiple cobordisms as well as the lengths of cobordisms derived from non-trivial loops of Legendrian isotopies.Comment: 33 pages, 9 figures. v2: Minor corrections in response to referee comments. More general statement in Proposition 3.3 and some reorganization at the end of Section

    Habitat Imaging Biomarkers for Diagnosis and Prognosis in Cancer Patients Infected with COVID-19

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    OBJECTIVES: Cancer patients have worse outcomes from the COVID-19 infection and greater need for ventilator support and elevated mortality rates than the general population. However, previous artificial intelligence (AI) studies focused on patients without cancer to develop diagnosis and severity prediction models. Little is known about how the AI models perform in cancer patients. In this study, we aim to develop a computational framework for COVID-19 diagnosis and severity prediction particularly in a cancer population and further compare it head-to-head to a general population. METHODS: We have enrolled multi-center international cohorts with 531 CT scans from 502 general patients and 420 CT scans from 414 cancer patients. In particular, the habitat imaging pipeline was developed to quantify the complex infection patterns by partitioning the whole lung regions into phenotypically different subregions. Subsequently, various machine learning models nested with feature selection were built for COVID-19 detection and severity prediction. RESULTS: These models showed almost perfect performance in COVID-19 infection diagnosis and predicting its severity during cross validation. Our analysis revealed that models built separately on the cancer population performed significantly better than those built on the general population and locked to test on the cancer population. This may be because of the significant difference among the habitat features across the two different cohorts. CONCLUSIONS: Taken together, our habitat imaging analysis as a proof-of-concept study has highlighted the unique radiologic features of cancer patients and demonstrated effectiveness of CT-based machine learning model in informing COVID-19 management in the cancer population

    High transferrin saturation predicts inferior clinical outcomes in patients with myelodysplastic syndromes

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    Iron overload (IO) reflected by elevated ferritin is associated with increased mortality in myelodysplastic syndromes (MDS), however, ferritin is an imperfect metric. Elevated labile plasma iron correlates with clinical outcomes and transferrin saturation (TSAT) >80%, but is not readily measurable. The trajectory of TSAT, and its association with clinical outcomes remain undefined. Canadian MDS registry patients were evaluated. Mean TSAT, mean ferritin and transfusion dose density (TDD) were determined. Survival was evaluated by TSAT and ferritin (80%), (≤500 μg/L, 501-800 μg/L, >800 μg/L). In 718 patients, median age was 74 years; 12%, 31%, 29%, 15% and 13% were IPSS-R very low, low, intermediate, high and very high. TSAT and ferritin were moderately correlated (r=0.63, P80% trended with inferior cardiac death-free survival (P=0.053). In univariate analysis, age, IPSS-R, blast percentage by Eastern Cooperative Oncology Group Performance Status, frailty, Charlson Comorbidity Index, iron chelation (Y/N), TDD, TSAT and ferritin were significantly associated with inferior OS. By multivariable analysis, TSAT >80% (P=0.007) remained significant for OS (R2 30.3%). In MDS, TSAT >80% and ferritin >800 μg/L portended inferior OS, PFS and LFS. TSAT may indicate the presence of oxidative stress, and is readily measurable in a clinical setting. The relationship between TSAT and cardiac death-free survival warrants further study

    Transplant Physicians’ Attitudes on Candidacy for Allogeneic Hematopoietic Cell Transplantation (HCT) in Older Patients: The Need for a Standardized Geriatric Assessment (GA) Tool

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    Background Despite improvements in conditioning regimens and supportive care having expanded the curative potential of HCT, underutilization of HCT in older adults persists (Bhatt VR et al, BMT 2017). Therefore, we conducted a survey of transplant physicians (TP) to determine their perceptions of the impact of older age (≥60 years) on HCT candidacy and utilization of tools to gauge candidacy. Methods We conducted a 23-item, online cross-sectional survey of adult physicians recruited from the Center for International Blood and Marrow Transplant Research between May and July 2019. Results 175/770 (22.7%) TP completed the survey; majority of respondents were 41-60 years old, male, and practicing in a teaching hospital. Over 75% were at centers performing ≥50 HCT per year. When considering regimen intensity, most (96%, n=168) had an upper age limit (UAL) for using a myeloablative regimen (MAC), with only 29 physicians (17%) stating they would consider MAC for patients ≥70 years. In contrast, when considering a reduced intensity/non-myeloablative conditioning (RIC/NMA), 8%, (n=13), 54% (n=93), and 20% (n=35) stated that age 70, 75, and 80 years respectively would be the UAL to use this approach, with 18% (n=31) reporting no UAL. TP agreed that Karnofsky Performance Score (KPS) could exclude older pts for HCT, with 39.1% (n=66), 42.6% (n=72), and 11.4% (n=20) requiring KPS of ≥70, 80, and 90, respectively. The majority (n=92, 52.5%) indicated an HCT-comorbidity index threshold for exclusion, mostly ranging from ≥3 to ≥ 5. Almost all (89.7%) endorsed the need for a better health assessment of pre-HCT vulnerabilities to guide candidacy for pts ≥60 with varied assessments being utilized beyond KPS (Figure 1). However, the majority of centers rarely (33.1%) or never (45.7%) utilize a dedicated geriatrician/geriatric-oncologist to assess alloHCT candidates ≥60 yrs. The largest barriers to performing GA included uncertainty about which tools to use, lack of knowledge and training, and lack of appropriate clinical support staff (Figure 2). Approximately half (n=78, 45%) endorsed GA now routinely influences candidacy. Conclusions The vast majority of TP will consider RIC/NMA alloHCT for patients ≥70 years. However, there is heterogeneity in assessing candidacy. Incorporation of GA into a standardized and easily applied health assessment tool for risk stratification is an unmet need. The recently opened BMT CTN 1704 may aid in addressing this gap

    Does FLT3 mutation impact survival after hematopoietic stem cell transplantation for acute myeloid leukemia? A Center for International Blood and Marrow Transplant Research (CIBMTR) analysis: Impact of FLT3 on OS Post-HCT for AML

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    BACKGROUND: Patients with FMS like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia (AML) have a poor prognosis and are referred for early allogeneic hematopoietic stem cell transplantation (HCT). METHODS: Data from the Center for International Blood and Marrow Transplant Research (CIBMTR) were used to evaluate 511 adult patients with de novo AML who underwent HCT during 2008 through 2011 to determine whether FLT3 mutations had an impact on HCT outcomes. RESULTS: In total, 158 patients (31%) had FLT3 mutations. Univariate and multivariate analyses revealed an increased risk of relapse at 3 years in the FLT3 mutated group compared with the wild-type (WT) group (38% [95% confidence interval (CI), 30%-45%] vs 28% [95% CI, 24%-33%]; P = .04; relative risk, 1.60 [95% CI, 1.15-2.22]; P = .0048). However, FLT3 mutation status was not significantly associated with nonrelapse mortality, leukemia-free survival, or overall survival. Although more patients in the FLT3 mutated group died from relapsed primary disease compared with those in the WT group (60% vs 46%), the 3-year overall survival rate was comparable for the 2 groups (mutated group: 49%; 95% CI, 40%-57%; WT group: 55%, 95% CI, 50%-60%; P = .20). CONCLUSIONS: The current data indicate that FLT3 mutation status did not adversely impact overall survival after HCT, and about 50% of patients with this mutation who underwent HCT were long-term survivors. Cancer 2016;122:3005-3014. © 2016 American Cancer Society

    Historical Archaeologies of the American West

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