Citations

Elasticity imaging methods have been used to study tissue mechanical properties and have demonstrated that tissue elasticity changes with disease state. Quantitative mechanical properties can be measured in a model independent manner if both shear wave speed and attenuation are known. However, measuring shear wave speed attenuation is challenging in the field of elasticity imaging. Typically, only shear wave speed is measured and rheological models, such as Kelvin-Voigt, Maxwell and Standard Linear Solid, are used to solve for shear viscoelastic complex modulus. Acoustic radiation force has been used to study quasi-static viscoelastic properties of tissue during creep and relaxation conditions, however, as with shear wave propagation methods, a rheological model needs to be fit to the creep or relaxation experimental data to solve for viscoelastic parameters. This paper presents a method to quantify viscoelastic properties in a model-independent way by estimating complex shear elastic modulus over a wide frequency range using time-dependent creep response induced by acoustic radiation force. The acoustic radiation force induced creep (RFIC) method uses a conversion formula that is the analytic solution of the constitutive equation relating time dependent stress and time dependent strain. The RFIC method in combination with shear wave propagation is used to measure the complex shear modulus so that knowledge of the applied radiation force magnitude is not necessary. Numerical simulation of creep strain and compliance using the Kelvin-Voigt model shown that the conversion formula is sensitive to sampling frequency, the first reliable measure in time and the long term viscosity approximation. Experimental data are obtained in homogeneous tissue mimicking phantoms and excised swine kidneys.

Background. Graft pretreatment to limit postoperative damage has the advantage of overcoming a current issue in liver transplantation (LT). The strategic potential of graft pretreatmentin vivoby a specific agonist forγ-aminobutyric acid receptor (GABAR) was investigated in the rat LT model with a small-for-size graft (SFSG).Methods. Recipient rats were divided into three groups according to donor treatments and recipient surgeries: (i) saline and laparotomy, (ii) saline and split orthotopic liver transplantation (SOLT) with 40%-SFSG, and (iii) GABAR agonist and SOLT with 40%-SFSG. Survival was evaluated. Blood and liver samples were collected 6 h after surgery. Immunohistological assessment for apoptotic induction and western blotting for 4-hydroxynonenal, ataxia-telangiectasia mutated kinase (ATM), histone H2AX, phosphatidylinositol-3 kinase (PI3K), Akt, and free radical scavenging enzymes were performed.Results. Pretreatment by GABAR showed improvement in survival, histopathological assessment, and biochemical tests. Apoptotic induction and oxidative stress were observed after SOLT with an SFSG, and this damage was limited by GABAR regulation. GABAR regulation appeared to reduce DNA damage via the ATM/H2AX pathway and to promote cell survival via the PI3K/Akt pathway.Conclusions. Pretreatmentin vivoby GABAR regulation improves graft damage after SOLT with an SFSG. This strategy may be advantageous in LT.

BackgroundWe aimed to test the hypothesis that three‐dimensional (3D) volume‐based scoring of computed tomography (CT) images of the paranasal sinuses was superior to Lund‐Mackay CT scoring of disease severity in chronic rhinosinusitis (CRS). We determined correlation between changes in CT scores (using each scoring system) with changes in other measures of disease severity (symptoms, endoscopic scoring, and quality of life) in patients with CRS treated with triamcinolone.MethodsThe study group comprised 48 adult subjects with CRS. Baseline symptoms and quality of life were assessed. Endoscopy and CT scans were performed. Patients received a single systemic dose of intramuscular triamcinolone and were reevaluated 1 month later. Strengths of the correlations between changes in CT scores and changes in CRS signs and symptoms and quality of life were determined.ResultsWe observed some variability in degree of improvement for the different symptom, endoscopic, and quality‐of‐life parameters after treatment. Improvement of parameters was significantly correlated with improvement in CT disease score using both CT scoring methods. However, volumetric CT scoring had greater correlation with these parameters than Lund‐Mackay scoring.ConclusionVolumetric scoring exhibited higher degree of correlation than Lund‐Mackay scoring when comparing improvement in CT score with improvement in score for symptoms, endoscopic exam, and quality of life in this group of patients who received beneficial medical treatment for CRS.

Sunitinib, a protein tyrosine kinase inhibitor is the frontline therapy for renal and gastrointestinal cancers. We hypothesized that by virtue of its well documented tumor apoptosis and immune adjuvant properties, combination of Sunitinib with anti‐tumor immunotherapeutics will provide synergistic inhibition of tumor growth. Our study was designed to evaluate the impact of Sunitinib on immunotherapy mediated anti‐tumor immune responses and evaluate its efficacy as a combinatorial therapy with tumor targeted immunotherapeutic vaccination. Mice immunized with recombinant α‐lactalbumin, a lactation protein expressed on majority of breast tumors were treated with 1 mg of Sunitinib for seven consecutive days beginning (1) concurrently, on the day of α‐lactalbumin immunization or (2) sequentially, on day 9 after immunization. Ten‐day lymph nodes or 21 day spleens were tested by ELISPOT assays and flow cytometry to evaluate responsiveness to α‐lactalbumin immunization in presence of Sunitinib and distribution of cells involved in T cell antigen priming and proliferation in different lymphoid compartments. In addition, therapeutic efficacy of the α‐lactalbumin/ Sunitinib combination was evaluated by monitoring tumor growth in the 4T1 transplanted tumor model. Our studies reveal that concurrent administration of Sunitinib with active vaccination against a targeted tumor antigen inhibits priming to the immunogen due to a drastic decrease in CD11b+CD11c+ antigen presenting cells, leading to failure of vaccination. However, sequential delivery of Sunitinib timed to avoid the priming phase of vaccination results in the desired vaccination mediated boost in immune responses.