Multi-interfacial microbubbles controlled sequential cavitation for synergistic vascular destruction/chemotherapeutic therapy.

PurposeTo evaluate the treatment effect of radiofrequency-induced hyperthermia (RFH) combined with intra-tumoral chemotherapy for rabbit VX2 liver tumors and explore the underlying mechanism that drives local hyperthermia-enhanced chemotherapy.Materials and MethodsVX2 cell lines and rabbits with liver VX2 tumors were randomly allocated to four treatment groups including: (1) combination therapy of Doxorubicin (DOX) plus hyperthermia/RFH (n=6); (2) DOX only; (3) hyperthermia/RFH only (n=6); and (4) phosphate-buffered saline-treated control (n=6). Cell viability and doxorubicin uptake by VX2 tumor cells were assayed using flow cytometry and fluorescence microscopy 24 h after treatments. Western blot was used to evaluate the expression level of heat shock protein 70 (HSP70) in tumor cells and tissues. For the harvested VX2 tumors, fluorescence microscopy was used to evaluate the distribution and penetration of doxorubicin in tumor tissues and HSP70 expression was analyzed by Western blot and immunohistochemistry.ResultsRFH enhanced the chemotherapeutic effect of doxorubicin in VX2 cells and rabbit liver VX2 tumors resulting in higher apoptosis and lower cell viability. Flowcytometry of VX2 cells showed more apoptotic cells in combination therapy of hyperthermia and DOX, compared with other three groups in-vitro experiments (45.80 ± 1.27% vs 20.66 ± 0.71%, vs 15.16 ± 0.81% and 0.62 ± 0.06%, respectively, p<0.01). The quantitative analysis by Western blot and immunohistochemistry showed increased expression of HSP70 in both VX2 tumor cells (1.28 ± 0.13 vs 0.64 ± 0.13 vs 0.83 ± 0.10 vs 0.15 ± 0.03, respectively, p<0.05) and tumors (1.47 ± 0.13 vs 0.51 ± 0.13 vs 0.74 ± 0.11 vs 0.16 ± 0.04, respectively, p <0.01). Fluorescence microscopy showed increased uptake of DOX in tumor cells in the combination therapy group.ConclusionsRFH/hyperthermia enhanced the chemotherapeutic effect of DOX in VX2 tumors by promoting the uptake of DOX and the expression HSP70 in tumors.

This research delves into the transfer and loss of energy in a discrete mass when subjected to forced vibration. Using discrete element method (DEM), we analyzed the dynamic behavior of regular spherical granular assemblies and the energy distribution characteristics under different excitation frequencies and reduced accelerations. Moreover, the energy transfer and dissipation process of granular assemblies under different vibration states are studied using an experimental method. The results show that the granular assemblies will produce collision energy dissipation, thermal energy dissipation, acoustic energy dissipation and other forms of energy dissipation in the forced vibration state and the proportion of different energy dissipation under different excitation is given. The collision and friction of granular assemblies are the key to affecting other forms of energy dissipation. When the excitation increases, the energy dissipation forms are generated inside the granular assemblies, and the proportion of collision energy dissipation of the granular assemblies increases. The acoustic energy above 20 kHz occupies the main part of the acoustic energy dissipation. Thermal energy consumption always exists, which takes a long time to play a role. The granular also have other forms of energy loss, which is hard to be measured, including Rayleigh waves generated by granular collision. In this study, the relationship between the forced vibration state of the granular assemblies and the energy loss distribution is established. Various types of energy transfer and conversion distribution which further enriches the energy dissipation of discrete element calculation of the granular assemblies is discussed and provides a reference for the energy loss analysis of the granular assemblies.

Background : The relationship between tumor vascularity and malignant potential in colorectal cancer a(CRC) is reported by many authors. Therefore, to assess the tumor vascularity before surgical treatment is thought to be one of very important factors in CRC patients. Contrast enhanced ultrasonography (CEUS) can visualize the tumor vascularity vividly. We aim to determine the reliability of CEUS for the assessment of vascularity of CRC and to analyze the relationship between tumor vascularity and clinicopathological characteristics. In addition, to find the clinical application, we assessed the efficacy of chemotherapy in unresectable advanced CRC patients by CEUS. Methods : 56 patients undergoing surgical resection of CRC were studied. An ultrasound system (GE health care, LOGIC 7) is used and visualized the colo-rectal tumor using a 4.5MHZ probe. The 2nd generated ultrasonic contrast medium (Belfulbuttan, Sonazoid) is injected intravenously. Approximately 20 s after injection, microbubbles were obtained to enhance the B-mode image. Using the tumor image showing the strongest vascularity, region of interest were determined to measure mean echo intensity in the tumor. Their images were analyzed with NIH image program (developed by the US National Institutes of health) and calculated tumor vascularity as Vascular Index (VI). The clinicopathological features are based on the TNM classification from UICC. Using surgical specimens, tumor vascularity was assessed by immunohistochemistry as microvessel density in order to do statistical analysis for the correlation between VI, clinicopathologic features and microvessel density. Results : CEUS could visualize the tumor vascularity in all patients. In advanced CRC patients, we observed that the tumor invaded into other organ, such as prostate gland, small intestine and so on. The VI correlated significantly with depth of tumor invasion, liver metastasis and microvessel density. Furthermore, in patients with abundant vascularity in tumor before treatment, chemotherapy led to the reduction of VI prior to the radiographically visible difference in tumor size. Conclusion : CEUS can evaluate the tumor vascularity non-invasively and is very useful for the evaluation of their pathological diagnosis and the efficacy of chemotherapy in CRC. Citation Format: Takaomi Okawa, Hiromi Nogami, Munenori Takaoka. Evaluation of tumor vascularity in colorectal cancer using contrast enhanced ultrasonograpy in comparison with microvessel density. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1501. doi:10.1158/1538-7445.AM2015-1501

Comparison of Contrast Enhanced Ultrasound and Contrast Enhanced CT or MRI in Monitoring Percutaneous Thermal Ablation Procedure in Patients with Hepatocellular Carcinoma: A Multi-Center Study in China

Facile fabrication of extreme-wettability contrast surfaces for efficient water harvesting using hydrophilic and hydrophobic silica nanoparticles

To determine the ability of contrast material-enhanced ultrasonography (US) to depict tumor growth and vascularity in a murine model of prostate carcinoma treated with an angiogenic inhibitor. Thirty-five genetically engineered mice with spontaneously occurring prostate tumors were monitored on a weekly basis with gray-scale and color Doppler US with a 15-MHz linear transducer. Eighteen mice were treated with an adenoviral vector to deliver a soluble form of the Flk1 receptor (VEGFR-2), a vascular endothelial growth factor receptor designed to block tumor angiogenesis. The remaining 17 animals were injected with saline and used as controls. Tumor volumes were calculated on the basis of serial US measurements. Color Doppler US was performed in every tumor before and after intravenous injection of 0.1 mL per kilogram of body weight of a US contrast agent. US images were evaluated for tumor size, pattern of vascularity, and extent of vascularity (vascularity index). Findings at US were correlated with findings at autopsy in 30 animals. Estimates of tumor volume at US correlated well with tumor measurements at autopsy (r =.89, P <.001). Marked differences in tumor size and slope of increasing tumor volume were evident at US between treated and control mice after treatment (P <.016, analysis of variance). The US contrast agent markedly increased color Doppler US signal intensity with an 800% (from 10% to 12,700%) change in the mean number of color pixels per imaging field, and showed vascularity in areas of tumor not identified on precontrast images in 70% (109 of 156 studies). No correlation was found between the pattern of vascularity or vascularity index before or after contrast material administration and tumor size, treatment status, or histologic assessment of tumor vascularity. Contrast-enhanced US improves visualization of tumor vascularity. However, histologic patterns of tumor vascularity do not correlate with Doppler US depiction of blood flow in these vessels.

The aim of the study was to quantitatively assess tumor microcirculation upon vascular targeting tumor therapy by non-destructive contrast enhanced ultrasonography (CEUS) and to validate this technology by correlation with high-resolution intravital fluorescence microscopy (IVM). Subcutaneous Lewis Lung carcinomas (LLC-1) carcinomas were established in mice. A-MEL-3 melanomas were grown in dorsal skinfold chambers of hamsters to permit bimodal imaging of tumor microcirculation by CEUS and IVM. Animals were treated by i.p. injection of ZD6126 and CEUS imaging after bolus injection of microbubbles was performed. Red blood cell velocity (VRBC), segmental blood flow (Q) and microcirculatory perfusion (PI) of tumors was quantified by IVM. Change in signal intensity (SI) from baseline (ΔSI), rate of SI increase (RSI) and area below intensity time curves (AUC) were calculated in tumors by analysis of CEUS data. Microvessel density was measured by quantitative analysis of CD31 immunohistochemistry. The Mann-Whitney test was used to evaluate differences between groups. Spearman correlation test was used to investigate the relation between CEUS and IVM parameters or histologic CD31 count. ΔSI, RSI and AUC values in ZD6126 treated tumors were lower compared to untreated controls. Comparing central and peripheral tumor regions a vascularized viable rim in the tumor periphery could be detected by CEUS imaging. For the entire cohort ΔSI, RSI and AUC values positively correlated with VRBC, Q and PI quantified by IVM. In LLC-1 carcinomas a positive correlation between ΔSI, RSI and AUC and histological assessment of tumor vascularity was found. In conclusion tumor vascular response to vascular targeting therapy can be quantified non-invasively by CEUS. Bimodal tumor imaging by intravital microscopy and CEUS represents an experimental tool to further develop molecular imaging of tumor microcirculation by CEUS.

Dynamics and acoustic energy dissipation in conical bubble collapse

Tumor-associated macrophages (TAMs) are increasingly considered a viable target for tumor imaging and therapy. Previously, we reported that innovative surface-functionalization of nanoparticles may help target them to TAMs. In this report, using poly(lactic-co-glycolic) acid (PLGA) nanoparticles incorporated with doxorubicin (DOX) (DOX-NPs), we studied the effect of surface-modification of the nanoparticles with mannose and/or acid-sensitive sheddable polyethylene glycol (PEG) on the biodistribution of DOX and the uptake of DOX by TAMs in tumor-bearing mice. We demonstrated that surface-modification of the DOX-NPs with both mannose and acid-sensitive sheddable PEG significantly increased the accumulation of DOX in tumors, enhanced the uptake of the DOX by TAMs, but decreased the distribution of DOX in mononuclear phagocyte system (MPS), such as liver. We also confirmed that the acid-sensitive sheddable PEGylated, mannose-modified DOX-nanoparticles (DOX-AS-M-NPs) targeted TAMs because depletion of TAMs in tumor-bearing mice significantly decreased the accumulation of DOX in tumor tissues. Furthermore, in a B16-F10 tumor-bearing mouse model, we showed that the DOX-AS-M-NPs were significantly more effective than free DOX in controlling tumor growth but had only minimum effect on the macrophage population in mouse liver and spleen. The AS-M-NPs are promising in targeting cytotoxic or macrophage-modulating agents into tumors to improve tumor therapy.

To quantify intratumoral ultrasonographic (US) contrast agent flow at gray-scale imaging as a measure of functional tumor vascularity in an orthotopic murine neuroblastoma model treated with angiogenesis inhibitors. After Institutional Animal Care and Use Committee approval, retroperitoneal neuroblastomas were established in mice with unmodified NXS2 cells (n = 13) or with cells engineered to overexpress an angiogenesis inhibitor--either tissue inhibitor of matrix metalloproteinase-3 (n = 22) or a truncated soluble form of the vascular endothelial growth factor receptor-2 (truncated soluble fetal liver kinase-1; n = 13). When tumors were approximately 600 mm3, contrast material-enhanced gray-scale US was performed, and the imaging was recorded on cine clips. Regions of interest within tumors were analyzed off-line to determine postcontrast change in signal intensity (SI) from baseline to initial peak (deltaSI), rate of SI increase from baseline to initial peak (RSI), and contrast material washout. The Mann-Whitney test was used to evaluate potential differences in these US parameters between treatment groups. The mean intratumoral endothelial cell (CD34) and pericyte (smooth muscle actin [SMA]) counts at immunohistochemical analysis were also evaluated. Spearman correlation test was used to investigate the relation between US parameters and these histologic markers. The deltaSI and RSI were lower in tumors overexpressing an angiogenesis inhibitor than in control tumors (all P < .03). Contrast material washout did not differ between groups. For the entire cohort, the RSI correlated with the immunohistochemical assessment of tumor vascularity (SMA and CD34 counts) (P < .003). Quantification of intratumoral flow of a US contrast agent at gray-scale imaging shows promise for monitoring tumor vascular response to antiangiogenic therapy.

In this paper, we report ultrasonically active nanoscale contrast agents that behave as thermometric sensors through phase change in their stabilizing phospholipid monolayer. Phospholipid-stabilized, hydrophobic mesoporous silica nanoparticles (P@hMSNs) are known to interact with high-intensity focused ultrasound (HIFU) to promote cavitation at their surfaces, which can be used for both imaging and therapy. We show that the lateral lipid phase behavior of the phosphocholine lipid dictates the acoustic contrast of the P@hMSNs. When the lipids are in the gel phase below their melting temperature, the P@hMSNs generate detectable microbubbles when exposed to HIFU. However, if the lipids exhibit a liquid expanded phase, the P@hMSNs cease to generate bubbles in response to HIFU insonation. We verify that the heating and subsequent transition of lipid coating the hMSN are associated with the loss of acoustic response by doping laurdan dye into the lipid monolayer and imaging lipid phase through red shifts in emission spectra. Similarly, cessation of cavitation was also induced by adding a fluidizing surfactant such as Triton X, which could be reversed upon washing away the excess surfactant. Finally, by controlling for the partial fluidization caused by the adsorption of protein, P@hMSNs may be used as thermometric sensors of the bulk fluid temperature. These findings not only impact the utilization of nanoscale agents as stimulus-responsive ultrasound contrast agents but also have broader implications for how cavitation may be initiated at surfaces coated by a surfactant.

Heat exchangers are of key importance in overall performance and commercialization of thermoacoustic devices. The main goal in designing efficient thermoacoustic heat exchangers (TAHXs) is the achievement of the required heat transfer rate in conjunction with low acoustic energy dissipation. A numerical investigation is performed to examine the effects of geometry on both the viscous and thermal-relaxation losses of shell-and-tube TAHXs. Further, the impact of the drive ratio as well as the temperature difference between the oscillating gas and the TAHX tube wall on acoustic energy dissipation are explored. While viscous losses decrease with d i / δ κ , thermal-relaxation losses increase; however, thermal relaxation effects mainly determine the acoustic power dissipated in TAHXs. The results indicate the existence of an optimal configuration for which the acoustic energy dissipation minimizes depending on both the TAHX metal temperature and the drive ratio.

Contrast agents

Pseudoangiomatous stromal hyperplasia (PASH), first described in 1986, is a benign breast lesion consisting of complex, anastomosing, slitlike pseudovascular spaces, which are either acellular or lined by slender, spindle-shaped cells. 1,2 The exact etiology of PASH is unknown. It usually presents as a breast mass, affecting women in their reproductive years. Pseudoangiomatous stromal hyperplasia has been reported in at least 25% of cases of gynecomastia. 2 Although PASH is a benign lesion, it has a propensity for growth over time and local recurrence after excision.3 Several small-scale studies already described the mammographic and gray scale ultrasonographic findings of PASH. 3,4,5 To our knowledge, the appearance of PASH on contrast-enhanced ultrasonography (CEUS) of the breast has never been described before. In past years, CEUS has been used increasingly in clinical practice to characterize indeterminate breast lesions. 6-14 In CEUS, a contrast agent consisting of a suspension of microbubbles is used to increase the blood echogenicity and to improve detection of slow and low-volume blood flow in microvessels (<5 μm). Because malignant breast tumors display neoangiogenesis that can be depicted by the contrast agent, it is believed that CEUS can be used to characterize breast masses and distinguish benign from malignant lesions. In this report, we describe the case of an elderly male patient with gynecomastia in whom conventional mammography and gray scale ultrasonography revealed a solid tumor in the left breast that was suggestive of malignancy. Additional workup of the lesion included CEUS of the breast with SonoVue (Bracco SpA, Milan, Italy) microbubbles to analyze tumor vascularization. On the basis of the CEUS findings, the lesion was down-staged to a benign breast lesion, probably a PASH. 6-13 After ultrasonographically guided biopsy of the lesion, histologic examination of the tissue confirmed the diagnosis. We describe the imaging characteristics of PASH on CEUS and provide an in-depth review of the literature.

To correlate the quantitated tumor vascularity of implanted murine tumors as depicted by contrast-enhanced sonography with estimates made with magnetic resonance imaging and with estimates of the percentage of viable (metabolically active) tumor as depicted by fluorodeoxyglucose autoradiography. Implanted tumors in 10 mice were imaged with contrast-enhanced sonography, magnetic resonance imaging, and fluorodeoxyglucose autoradiography. Tumor vascularity was estimated with each modality and compared with the percentage of viable tumor. Quantitated estimates of tumor vascularity with contrast-enhanced sonography closely correlated (r = 0.95) with estimates made by magnetic resonance imaging and with the percentage of viable tumor (r = 0.93) as depicted by fluorodeoxyglucose autoradiography. Contrast-enhanced sonography accurately depicts tumor vascularity in these implanted tumors. Tumor vascularity correlated with the amount of metabolically active tumor.