Citations

MRI guided focused ultrasound (FUS) has been shown to create thermal lesions where tissue stiffness changes significantly. To assess the correlation between tissue stiffness change and tissue ablation, a pilot animal based study was conducted to treat LNCaP tumors in vivo and Hep3B tumors immediately post mortem. MR elastography was used to analyze tissue stiffness before and after ablation. Treated tissue was excised immediately after each experiment and processed by routine histological analysis. Four prostate cancer tumors and four liver cancer tumors showed, on average, a threefold increase in stiffness due to FUS thermal treatment. Histology showed complete (100%) coagulation necrosis in these cases. These data suggest that MRE may be an effective means to assess tissue ablation.

In paper, we report our recent results of using the air force ultrasound transducer to study the resonance of rubber tubes. Experiments were carried out on a rubber latex tube. Seven resonant frequencies were measured between 50 Hz and 200 Hz. Theoretical calculation of the resonant frequency on the tube was done with the wave propagation approach. The relative differences of the seven resonant frequencies between the experiment and the theory are less than 6 %. This research shows that the air force ultrasound transducer can be used for tube resonance measurement.

A custom computer-controlled rapid prototyping system was designed and developed in this research. This system for bio-manufacturing of polymer scaffolds included 3D motion control components, a nozzle, a pressure controller, and a temperature-controlled reservoir containing a biomaterial. Heating elements built into the reservoir melted the biomaterial. The pressure line attached to the reservoir provided a controllable force that extruded the polymer biomaterial through the nozzle and deposited the polymer biomaterial onto a platform to fabricate scaffolds. A low pressure (830 KPa) system was designed and fabricated to accommodate different temperatures, motion speeds, and viscosities of polymer biomaterials. The reservoir with the nozzle was mounted to servo motor-controlled linear x-y motion devices along with a third servo motor-controlled device that controlled the z-position of the platform. Poly(ε-caprolactone) [PCL] was used to fabricate scaffolds with designed structure that were used in cell and tissue regeneration studies. 3D computer-aided design (CAD) with Pro-Engineer and computational finite element analysis (FEA) programs with MSC_Patran and MSC_Marc were used to model scaffold designs with appropriate architecture and material selection. The CAD models were used in FEA to develop new methods for determining mechanical properties of tissue scaffolds of desired structure and geometry. FEA models were validated by mechanical testing and other published results. Technology developed in this research has potential for the advancement of bio-manufacturing, and design optimization of scaffolds for tissue engineering.

This article discusses the possibility of using microbubble contrast agents in the Vibro-Acoustography (VA) technique. An existing mathematical model is used to determine the interaction of encapsulated microbubbles with VA ultrasound fields. Such models may lead to a better understanding of the underlying mechanics and interactions in clinical settings.

ABSTRACT Patients recruited in virus-based cancer clinical trials and immunocompromised individuals in need of vaccination would profit from viral strains with defined attenuation mechanisms. We generated measles virus (MV) strains defective for the expression of either the V protein, a modulator of the innate immune response, or the C protein, which has multiple functions. The virulence of these strains was compared with that of the parental wild-type MV in a natural host, Macaca mulatta . Skin rash, viremia, and the strength of the innate and adaptive immune responses were characterized in groups of six animals. Replication of V- or C-protein-defective viruses was short-lived and reached lower levels in peripheral blood mononuclear cells and lymphatic organs compared to the wild-type virus; none of the mutants reverted to the wild type. The neutralizing antibody titers and MV-specific T-cell responses were equivalent in monkeys infected with the viral strains tested, documenting strong adaptive immune responses. In contrast, the inflammatory response was better controlled by wild-type MV, as revealed by inhibition of interleukin-6 and tumor necrosis factor alpha transcription. The interferon response was also better controlled by the wild-type virus than by the defective viruses. Since V- and C-defective MVs induce strong adaptive immune responses while spreading less efficiently, they may be developed as vaccines for immunocompromised individuals. Moreover, MV unable to interact with single innate immunity proteins may be developed for preferential replication in tumors with specific contexts of vulnerability.

Three non-destructive testing techniques are developed and investigated to determine the Young’s modulus of elasticity of the trachea and the results are compared with the standard uniaxial state of stress method. These techniques are based on: (1) simulating the trachea as a pressurized vessel and deducing a special relationship between the pressure and the radial strain; (2) using two hydrophones and determining the variation in acoustic transmittance caused by the presence of the trachea in a propagation path within a water-bath; (3) considering the trachea as a thin cylindrical shell and determining the resonance radial vibration response. Discussion is presented to identify the “pros” and “cons” of each technique and final practical recommendations are made.

Abstract Investment analysts are a growing presence at the Annual Meeting of the American Society of Hematology (ASH), and financial professionals frequently contact ASH members for information and perspective on drugs, devices, and scientific developments. Recent incidents have raised concerns about consulting relationships between physicians and the investment industry; the appropriate role of medical societies in influencing these relationships is unclear. In this essay, I summarize the current situation, discuss potential risks and benefits from interactions between physicians and investment analysts, and outline issues that all individuals involved in investment industry consulting should consider. I also propose changes in ASH policy that may help safeguard public trust as well as preserve the access of clinicians and scientists to clinically relevant data presented at the Annual Meeting.

Prior studies have suggested the possibility of immune-mediated death of xenogeneic hepatocytes in a bioartificial liver (BAL) during hemoperfusion. This study was designed to elucidate how immunity may cause death of xenogeneic hepatocytes in the BAL. Healthy dogs were treated with a BAL containing hollow fiber membranes with large pores (200 nm) or small pores (400 kDa). The immune response of recipient dogs to BAL therapy was monitored over 3 h of treatment. We observed significantly greater loss of viability of hepatocytes in the 200 nm group compared with the 400 kDa group (p < 0.001). Low viability after treatment with the large pore membrane was associated with positive staining for dog IgG, dog IgM, and dog complement on dead hepatocytes. Significant levels of dog antibody were detected in samples of BAL medium from the 200 nm group. These canine antibodies were cytotoxic to porcine hepatocytes. In contrast, medium from the 400 kDa group contained only trace levels of dog IgG and were noncytotoxic. We conclude that antibody-mediated cytotoxicity contributed to the death of hepatocytes during treatment with a xenogeneic BAL. Immune-mediated death of hepatocytes was reduced by increasing selectivity of the BAL membrane.