338 research outputs found

    Oral leukoplakia and risk of progression to oral cancer: A population-based cohort study

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    BACKGROUND: The optimal clinical management of oral precancer remains uncertain. We investigated the natural history of oral leukoplakia, the most common oral precancerous lesion, to estimate the relative and absolute risks of progression to cancer, the predictive accuracy of a clinician\u27s decision to biopsy a leukoplakia vis-à-vis progression, and histopathologic predictors of progression. METHODS: We conducted a retrospective cohort study (1996-2012) of patients with oral leukoplakia (n = 4886), identified using electronic medical records within Kaiser Permanente Northern California. Among patients with leukoplakia who received a biopsy (n = 1888), we conducted a case-cohort study to investigate histopathologic predictors of progression. Analyses included indirect standardization and unweighted or weighted Cox regression. RESULTS: Compared with the overall Kaiser Permanente Northern California population, oral cancer incidence was substantially elevated in oral leukoplakia patients (standardized incidence ratio = 40.8, 95% confidence interval [CI] = 34.8 to 47.6; n = 161 cancers over 22 582 person-years). Biopsied leukoplakias had a higher oral cancer risk compared with those that were not biopsied (adjusted hazard ratio = 2.38, 95% CI = 1.73 to 3.28). However, to identify a prevalent or incident oral cancer, the biopsy decision had low sensitivity (59.6%), low specificity (62.1%), and moderate positive-predictive value (5.1%). Risk of progression to oral cancer statistically significantly increased with the grade of dysplasia; 5-year competing risk-adjusted absolute risks were: leukoplakia overall = 3.3%, 95% CI = 2.7% to 3.9%; no dysplasia = 2.2%, 95% CI = 1.5% to 3.1%; mild-dysplasia = 11.9%, 95% CI = 7.1% to 18.1%; moderate-dysplasia = 8.7%, 95% CI = 3.2% to 17.9%; and severe dysplasia = 32.2%, 95% CI = 8.1%-60.0%. Yet 39.6% of cancers arose from biopsied leukoplakias without dysplasia. CONCLUSIONS: The modest accuracy of the decision to biopsy a leukoplakia vis-à-vis presence or eventual development of oral cancer highlights the need for routine biopsy of all leukoplakias regardless of visual or clinical impression. Leukoplakia patients, particularly those with dysplasia, need to be closely monitored for signs of early cancer

    MIBG avidity correlates with clinical features, tumor biology, and outcomes in neuroblastoma: A report from the Children’s Oncology Group

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    BackgroundPrior studies suggest that neuroblastomas that do not accumulate metaiodobenzylguanidine (MIBG) on diagnostic imaging (MIBG non‐avid) may have more favorable features compared with MIBG avid tumors. We compared clinical features, biologic features, and clinical outcomes between patients with MIBG nonavid and MIBG avid neuroblastoma.ProcedurePatients had metastatic high‐ or intermediate‐risk neuroblastoma and were treated on Children’s Oncology Group protocols A3973 or A3961. Comparisons of clinical and biologic features according to MIBG avidity were made with chi‐squared or Fisher exact tests. Event‐free (EFS) and overall (OS) survival compared using log–rank tests and modeled using Cox models.ResultsThirty of 343 patients (8.7%) had MIBG nonavid disease. Patients with nonavid tumors were less likely to have adrenal primary tumors (34.5 vs. 57.2%; P = 0.019), bone metastases (36.7 vs. 61.7%; P = 0.008), or positive urine catecholamines (66.7 vs. 91.0%; P < 0.001) compared with patients with MIBG avid tumors. Nonavid tumors were more likely to be MYCN amplified (53.8 vs. 32.6%; P = 0.030) and had lower norepinephrine transporter expression. Patients with MIBG nonavid disease had a 5‐year EFS of 50.0% compared with 38.7% for patients with MIBG avid disease (P = 0.028). On multivariate testing in high‐risk patients, MIBG avidity was the sole adverse prognostic factor for EFS identified (hazard ratio 1.77; 95% confidence interval 1.04–2.99; P = 0.034).ConclusionsPatients with MIBG nonavid neuroblastoma have lower rates of adrenal primary tumors, bone metastasis, and catecholamine secretion. Despite being more likely to have MYCN‐amplified tumors, these patients have superior outcomes compared with patients with MIBG avid disease.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138438/1/pbc26545_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138438/2/pbc26545.pd

    Electromagnetically Induced Transparency and Slow Light with Optomechanics

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    Controlling the interaction between localized optical and mechanical excitations has recently become possible following advances in micro- and nano-fabrication techniques. To date, most experimental studies of optomechanics have focused on measurement and control of the mechanical subsystem through its interaction with optics, and have led to the experimental demonstration of dynamical back-action cooling and optical rigidity of the mechanical system. Conversely, the optical response of these systems is also modified in the presence of mechanical interactions, leading to strong nonlinear effects such as Electromagnetically Induced Transparency (EIT) and parametric normal-mode splitting. In atomic systems, seminal experiments and proposals to slow and stop the propagation of light, and their applicability to modern optical networks, and future quantum networks, have thrust EIT to the forefront of experimental study during the last two decades. In a similar fashion, here we use the optomechanical nonlinearity to control the velocity of light via engineered photon-phonon interactions. Our results demonstrate EIT and tunable optical delays in a nanoscale optomechanical crystal device, fabricated by simply etching holes into a thin film of silicon (Si). At low temperature (8.7 K), we show an optically-tunable delay of 50 ns with near-unity optical transparency, and superluminal light with a 1.4 microseconds signal advance. These results, while indicating significant progress towards an integrated quantum optomechanical memory, are also relevant to classical signal processing applications. Measurements at room temperature and in the analogous regime of Electromagnetically Induced Absorption (EIA) show the utility of these chip-scale optomechanical systems for optical buffering, amplification, and filtering of microwave-over-optical signals.Comment: 15 pages, 9 figure

    Thyroid and hepatic function after high-dose 131 I-metaiodobenzylguanidine ( 131 I-MIBG) therapy for neuroblastoma.

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    Background 131 I-Metaiodobenzylguanidine ( 131 I-MIBG) provides targeted radiotherapy for children with neuroblastoma, a malignancy of the sympathetic nervous system. Dissociated radioactive iodide may concentrate in the thyroid, and 131 I-MIBG is concentrated in the liver after 131 I-MIBG therapy. The aim of our study was to analyze the effects of 131 I-MIBG therapy on thyroid and liver function. Procedure Pre- and post-therapy thyroid and liver functions were reviewed in a total of 194 neuroblastoma patients treated with 131 I-MIBG therapy. The cumulative incidence over time was estimated for both thyroid and liver toxicities. The relationship to cumulative dose/kg, number of treatments, time from treatment to follow-up, sex, and patient age was examined. Results In patients who presented with Grade 0 or 1 thyroid toxicity at baseline, 12 ± 4% experienced onset of or worsening to Grade 2 hypothyroidism and one patient developed Grade 2 hyperthyroidism by 2 years after 131 I-MIBG therapy. At 2 years post- 131 I-MIBG therapy, 76 ± 4% patients experienced onset or worsening of hepatic toxicity to any grade, and 23 ± 5% experienced onset of or worsening to Grade 3 or 4 liver toxicity. Liver toxicity was usually transient asymptomatic transaminase elevation, frequently confounded by disease progression and other therapies. Conclusion The prophylactic regimen of potassium iodide and potassium perchlorate with 131 I-MIBG therapy resulted in a low rate of significant hypothyroidism. Liver abnormalities following 131 I-MIBG therapy were primarily reversible and did not result in late toxicity. 131 I-MIBG therapy is a promising treatment for children with relapsed neuroblastoma with a relatively low rate of symptomatic thyroid or hepatic dysfunction. Pediatr Blood Cancer 2011;56:191–201. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78497/1/22767_ftp.pd

    Observation of exclusive DVCS in polarized electron beam asymmetry measurements

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    We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.Comment: 6 pages, 5 figure

    Innate Immune Suppression Enables Frequent Transfection with RNA Encoding Reprogramming Proteins

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    BACKGROUND: Generating autologous pluripotent stem cells for therapeutic applications will require the development of efficient DNA-free reprogramming techniques. Transfecting cells with in vitro-transcribed, protein-encoding RNA is a straightforward method of directly expressing high levels of reprogramming proteins without genetic modification. However, long-RNA transfection triggers a potent innate immune response characterized by growth inhibition and the production of inflammatory cytokines. As a result, repeated transfection with protein-encoding RNA causes cell death. METHODOLOGY/PRINCIPAL FINDINGS: RNA viruses have evolved methods of disrupting innate immune signaling by destroying or inhibiting specific proteins to enable persistent infection. Starting from a list of known viral targets, we performed a combinatorial screen to identify siRNA cocktails that could desensitize cells to exogenous RNA. We show that combined knockdown of interferon-beta (Ifnb1), Eif2ak2, and Stat2 rescues cells from the innate immune response triggered by frequent long-RNA transfection. Using this technique, we were able to transfect primary human fibroblasts every 24 hours with RNA encoding the reprogramming proteins Oct4, Sox2, Klf4, and Utf1. We provide evidence that the encoded protein is active, and we show that expression can be maintained for many days, through multiple rounds of cell division. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that suppressing innate immunity enables frequent transfection with protein-encoding RNA. This technique represents a versatile tool for investigating expression dynamics and protein interactions by enabling precise control over levels and timing of protein expression. Our finding also opens the door for the development of reprogramming and directed-differentiation methods based on long-RNA transfection

    In situ size sorting in CVD synthesis of Si microspheres

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    [EN] Silicon microspheres produced in gas-phase by hot-wall CVD offer unique quality in terms of sphericity, surface smoothness, and size. However, the spheres produced are polydisperse in size, which typically range from 0.5 mu m to 5 mu m. In this work we show through experiments and calculations that thermophoretic forces arising from strong temperature gradients inside the reactor volume effectively sort the particles in size along the reactor. These temperature gradients are shown to be produced by a convective gas flow. The results prove that it is possible to select the particle size by collecting them in a particular reactor region, opening new possibilities towards the production by CVD of size-controlled high-quality silicon microspheres.The authors acknowledge financial support from the following projects: ENE2013-49984-EXP, MAT2012-35040, MAT2015-69669-P and ESP2014-54256-C4-2-R of the Spanish Ministry of Economy and Competitiveness (MINECO), and PROMETEOII/2014/026 of the Regional Valencian Government.Garín Escrivá, M.; Fenollosa Esteve, R.; Kowalski, L. (2016). In situ size sorting in CVD synthesis of Si microspheres. Scientific Reports. 6:1-10. https://doi.org/10.1038/srep38719S110
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