206 research outputs found

    South American giant short-faced bear (Arctotherium angustidens) diet: evidence from pathology, morphology, stable isotopes, and biomechanics

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    Fil: Soibelzon, Leopoldo HĂ©ctor. DivisiĂłn PaleontologĂ­a Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Grinspan, Gustavo A.. NĂșcleo de BiomecĂĄnica. Espacio Interdisciplinario. Universidad de la RepĂșblica. Montevideo; UruguayFil: Bocherens, HervĂ©. Department of Geosciences. Biogeology. University TĂŒbingen. TĂŒbingen; GermanyFil: Acosta, Walter G.. CĂĄtedra de SemiologĂ­a. Facultad de Ciencias Veterinarias. Universidad Nacional de La Plata; ArgentinaFil: Jones, Washington. NĂșcleo de BiomecĂĄnica. Espacio Interdisciplinario. Universidad de la RepĂșblica. Montevideo; UruguayFil: Blanco, Ernesto R.. nstituto de FĂ­sica. Facultad de Ciencias. Universidad de la RepĂșblica. Montevideo; UruguayFil: Prevosti, Francisco. DivisiĂłn MastozoologĂ­a. Museo Argentino de Ciencias Naturales Bernardino Rivadavia. Buenos Aires; Argentin

    Surface wave elastography is a reliable method to correlate muscle elasticity, torque, and electromyography activity level

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    Abstract The shear elastic modulus is one of the most important parameters to characterize the mechanical behavior of soft tissues. In biomechanics, ultrasound elastography is the gold standard for measuring and mapping it locally in skeletal muscle in vivo. However, their applications are limited to the laboratory or clinic. Thus, low‐frequency elastography methods have recently emerged as a novel alternative to ultrasound elastography. Avoiding the use of high frequencies, these methods allow obtaining a mean value of bulk shear elasticity. However, they are frequently susceptible to diffraction, guided waves, and near field effects, which introduces biases in the estimates. The goal of this work is to test the performance of the non‐ultrasound surface wave elastography (NU‐SWE), which is portable and is based on new algorithms designed to correct the incidence of such effects. Thus, we show its first application to muscle biomechanics. We performed two experiments to assess the relationships of muscle shear elasticity versus joint torque (experiment 1) and the electromyographic activity level (experiment 2). Our results were comparable regarding previous works using the reference ultrasonic methods. Thus, the NU‐SWE showed its potentiality to get wide the biomechanical applications of elastography in many areas of health and sports sciences

    Recall patterns and risk of primary liver cancer for subcentimeter ultrasound liver observations: a multicenter study

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    BACKGROUND: Patients with cirrhosis and subcentimeter lesions on liver ultrasound are recommended to undergo short-interval follow-up ultrasound because of the presumed low risk of primary liver cancer (PLC). AIMS: The aim of this study is to characterize recall patterns and risk of PLC in patients with subcentimeter liver lesions on ultrasound. METHODS: We conducted a multicenter retrospective cohort study among patients with cirrhosis or chronic hepatitis B infection who had subcentimeter ultrasound lesions between January 2017 and December 2019. We excluded patients with a history of PLC or concomitant lesions ≄1 cm in diameter. We used Kaplan Meier and multivariable Cox regression analyses to characterize time-to-PLC and factors associated with PLC, respectively. RESULTS: Of 746 eligible patients, most (66.0%) had a single observation, and the median diameter was 0.7 cm (interquartile range: 0.5-0.8 cm). Recall strategies varied, with only 27.8% of patients undergoing guideline-concordant ultrasound within 3-6 months. Over a median follow-up of 26 months, 42 patients developed PLC (39 HCC and 3 cholangiocarcinoma), yielding an incidence of 25.7 cases (95% CI, 6.2-47.0) per 1000 person-years, with 3.9% and 6.7% developing PLC at 2 and 3 years, respectively. Factors associated with time-to-PLC were baseline alpha-fetoprotein \u3e10 ng/mL (HR: 4.01, 95% CI, 1.85-8.71), platelet count ≀150 (HR: 4.90, 95% CI, 1.95-12.28), and Child-Pugh B cirrhosis (vs. Child-Pugh A: HR: 2.54, 95% CI, 1.27-5.08). CONCLUSIONS: Recall patterns for patients with subcentimeter liver lesions on ultrasound varied widely. The low risk of PLC in these patients supports short-interval ultrasound in 3-6 months, although diagnostic CT/MRI may be warranted for high-risk subgroups such as those with elevated alpha-fetoprotein levels

    Neuregulin 1 Type III/ErbB Signaling Is Crucial for Schwann Cell Colonization of Sympathetic Axons

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    Analysis of Schwann cell (SC) development has been hampered by the lack of growing axons in many commonly used in vitro assays. As a consequence, the molecular signals and cellular dynamics of SC development along peripheral axons are still only poorly understood. Here we use a superior cervical ganglion (SCG) explant assay, in which axons elongate after treatment with nerve growth factor (NGF). Migration as well as proliferation and apoptosis of endogenous SCG-derived SCs along sympathetic axons were studied in these cultures using pharmacological interference and time-lapse imaging. Inhibition of ErbB receptor tyrosine kinases leads to reduced SC proliferation, increased apoptosis and thereby severely interfered with SC migration to distal axonal sections and colonization of axons. Furthermore we demonstrate that SC colonization of axons is also strongly impaired in a specific null mutant of an ErbB receptor ligand, Neuregulin 1 (NRG1) type III. Taken together, using a novel SC development assay, we demonstrate that NRG1 type III serves as a critical axonal signal for glial ErbB receptors that drives SC development along sympathetic axons
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