Enhanced cell killing and apoptosis of oral squamous cell carcinoma cells with ultrasound in combination with cetuximab coated albumin microbubbles.

Targeted microbubbles have the potential to be used for ultrasound (US) therapy and diagnosis of various cancers. In the present study, US was irradiated to oral squamous cell carcinoma cells (HSC-2) in the presence of cetuximab-coated albumin microbubbles (CCAM). Cell killing rate with US treatment at 0.9 W/cm2 and 1.0 W/cm2 in the presence of CCAM was greater compared to non-targeted albumin microbubbles (p < .05). On the other hand, selective cell killing was not observed in human myelomonocytic lymphoma cell line (U937) that had no affinity to cetuximab. Furthermore, US irradiation in the presence of CCAM showed a fivefold increase of cell apoptotic rate for HSC-2 cells (21.0 ± 3.8%) as compared to U937 cells (4.0 ± 0.8%). Time-signal intensity curve in a tissue phantom demonstrated clear visualisation of CCAM with conventional US imaging device. Our experiment verifies the hypothesis that CCAM was selective to HSC-2 cells and may be applied as a novel therapeutic/diagnostic microbubble for oral squamous cell carcinoma.

Oral surgery under local anesthesia with dexmedetomidine sedation in a morbidly obese patient with aortic dissection.

We report a case of a morbidly obese man with an aortic aneurysm, in whom dental surgery was performed before elective cardiac surgery. His aortic aneurysm required emergency surgery. However, because of his morbid obesity, elective cardiac surgery was planned. Considering the high risk of infective endocarditis, dental surgery was required. Our patient was at a high risk of aortic rupture caused by hypertension and breathing difficulty in the supine position. Dexmedetomidine (DEX) is an anti-anxiety, sedative, and analgesic medicine that can stabilize circulatory dynamics and minimize blood pressure fluctuations. We administered intravenous DEX for sedation of the patient in Fowler's position. In conclusion, our understanding of the risk factors of DEX enabled us to perform safe invasive oral treatment.

Acute effects of sono-activated photocatalytic titanium dioxide nanoparticles on oral squamous cell carcinoma.

Sonodynamic therapy (SDT) is a new treatment modality using ultrasound to activate certain chemical sensitizers for cancer therapy. In this study, effects of high intensity focused ultrasound (HIFU) combined with photocatalytic titanium dioxide (TiO2) nanoparticles on human oral squamous cell line HSC-2 were investigated. Viability of HSC-2 cells after 0, 0.1, 1, or 3s of HIFU irradiation with 20, 32, 55 and 73Wcm(-2) intensities in the presence or absence of TiO2 was measured immediately after the exposures in vitro. Immediate effects of HIFU (3s, 73Wcm(-2)) combined with TiO2 on solid tumors were also examined by histological study. Cytotoxic effect of HIFU+TiO2in vitro was significantly higher than that of TiO2 or HIFU alone with the tendency to increase for higher HIFU intensity, duration, and TiO2 concentration in the suspension. In vivo results showed significant necrosis and tissue damage in HIFU and HIFU+TiO2 treated samples. However, penetration of TiO2 nanoparticles into the cell cytoplasm was only observed in HIFU+TiO2 treated tissues. In this study, our findings provide a rational basis for the development of an effective HIFU based sonodynamic activation method. This approach offers an attractive non-invasive therapy technique for oral cancer in future.

Enhanced mechanical damage to in vitro cancer cells by high-intensity-focused ultrasound in the presence of microbubbles and titanium dioxide.

PURPOSE: To evaluate in vitro the feasibility of therapeutic high-intensity-focused ultrasound (HIFU) combined with microbubbles and titanium dioxide (TiO2). METHODS: Oral squamous cell carcinoma cells (HSC-2) were sonicated using a HIFU transducer with a resonant frequency of 3.5 MHz, 30 mm in diameter, and focal length of 50 mm. The ultrasound intensity was 210 W/cm(2), and two pulses (0.5 s each) were sonicated for each cell sample (9 × 10(4) cells per well). Immediately after HIFU, the viable cells were measured by an automated cell counter. The survival rate was measured in the presence of microbubbles (Sonazoid) and peroxo titania-silica (R-P-TS) or anatase titania-silica (R-A-TS) TiO2. RESULTS: Cell viability immediately following sonication in the presence of TiO2 (R-A-TS) and TiO2 (R-P-TS) was 65.5 ± 0.7 and 59.4 ± 3.3 %, respectively. A marked decrease in cell viability was seen when microbubbles were added to the above cell conditions. Specifically, cell viability decreased to 14.0 ± 0.1 and 4.4 ± 0.9 % when microbubbles were added to samples containing TiO2 (R-A-TS) and TiO2 (R-P-TS), respectively. CONCLUSION: Immediate in vitro cell killing was observed with short pulsed duration HIFU sonication with a combination of microbubbles and TiO2. This finding suggests that TiO2 could have caused enhanced mechanical cell destruction by microbubbles.