Kazutaka Mitobe

Inhibition of heat shock protein 90 sensitizes melanoma cells to thermosensitive ferromagnetic particle-mediated hyperthermia with low Curie temperature

Heat shock protein (Hsp) 90 is a key regulator of a variety of oncogene products and cell‐signaling molecules, and the therapeutic benefit of its inhibition in combination with radiation or chemotherapy has been investigated. In addition, hyperthermia has been used for many years to treat various malignant tumors. We previously described a system in which hyperthermia was induced using thermosensitive ferromagnetic particles (FMP) with a Curie temperature (Tc = 43˚C) low enough to mediate automatic temperature control, and demonstrated its antitumor effect in a mouse melanoma model. In the present study, we examined the antitumor effects of combining a Hsp90 inhibitor (geldanamycin; GA) with FMP‐mediated hyperthermia. In cultured B16 melanoma cells, GA exerted an antitumor effect by increasing the cells’ susceptibility to hyperthermia and reducing expression of Akt. In an in vivo study, melanoma cells were subcutaneously injected into the backs of C57BL/6 mice. FMP were then injected into the resultant tumors, and the mice were divided into four groups: group I, no treatment (control); group II, one hyperthermia treatment; group III, GA alone; and group IV, GA with hyperthermia. When exposed to a magnetic field, the temperature of tissues containing FMP increased and stabilized at the Tc. In group IV, complete regression of tumors was observed in five of nine mice (56%), whereas no tumor regression was seen in groups I–III. Our findings suggest that inhibition of Hsp90 with hyperthermia increases its antitumor effect. Thus, the combination of FMP‐mediated, self‐regulating hyperthermia with Hsp90 inhibition has important implications for the treatment of cancer. (Cancer Sci 2009; 100: 558–564)

Self-regulating hyperthermia induced using thermosensitive ferromagnetic material with a low Curie temperature

Hyperthermia has been used for many years to treat a variety of malignant tumors. The Curie temperature (Tc) is a transition point at which magnetic materials lose their magnetic properties, causing a cessation of current and thus heat production. The Tc enables automatic temperature control throughout a tumor as a result of the self‐regulating nature of the thermosensitive material. We have developed a method of magnetically‐induced hyperthermia using thermosensitive ferromagnetic particles (FMPs) with low Tc (43°C), enough to mediate automatic temperature control. B16 melanoma cells were subcutaneously injected into the backs of C57BL/6 mice, after which tumors were allowed to grow to 5 mm in diameter. FMPs were then injected into the tumors, and the mice were divided into three groups: group I (no hyperthermia, control); group II (one hyperthermia treatment); and group III (hyperthermia twice a week for 4 weeks). When exposed to a magnetic field, the FMPs showed a sharp rise in heat production, reaching the Tc in tissue within 7 min, after which the tissue temperature stabilized at approximately the Tc. In groups I and II, all mice died within 30–45 days. In group III, however, 6 of 10 mice remained alive 120 days after beginning treatment. Our findings suggest that repeated treatment with magnetically‐induced self‐regulating hyperthermia, mediated by FMPs with a low Tc, is an effective means of suppressing melanoma growth. A key advantage of this hyperthermia system is that it is minimally invasive, requiring only a single injection for repeated treatments with automatic temperature control. (Cancer Sci 2008; 99: 805–809)

Application of Terahertz Imaging to Water Content Measurement

We proposed a quantitative method to calculate water content of thin materials by terahertz (THz) imaging. First, we constructed a THz imaging system using a tunnel injection transit time (TUNNETT) THz wave generator with automatic scanning control. As a suitable imaging spatial resolution is necessary to accurately estimate water content and distribution in samples, we have improved the spatial resolution. Images of plant leaves under different conditions were taken using the THz imaging system. We have introduced an algorithm with the attenuation law of Lambert–Beer to calculate water contents from THz images. To verify the accuracy of this method, we also obtained images of a piece of cotton cloth with different contents of water. Comparison of the calculated values with the measured values obtained using an electronic balance showed that our method has a good possibility for measuring the water content of relatively thin materials by a noncontact and noninvasive method using THz images.

Noninvasive temperature measurement method for hyperthermia treatment using ferromagnetic implant with low Curie temperature

Induction heating using ‘ferromagnetic implant with low Curie temperature (FILCT)’ is one of the heating methods for hyperthermia. However, a lot of energy is needed to heat malignant tumors; the heating efficiency has to be improved. In order to address this problem, we propose using FILCT as a probe for temperature. A non-invasive temperature measurement system was developed based on this approach. A key advantage of this system is that it can noninvasively distinguish whether the temperature of FILCT has reached the Curie temperature or not. As a result, materials with high heating efficiency may be used.

Terahertz imaging for water content measurement

We proposed a quantitative method to calculate water content of the thin materials by terahertz (THz) imaging. First, we constructed a THz imaging system by using a Tunnel injection Transit Time (TUNNETT) THz wave generator with automatic scanning control. Images of the plant leaves under different conditions were taken with the THz imaging system. We have introduced an algorithm with the attenuation law of Lambert-Beer to calculate the water contents from the THz imaging. To verify the accuracy of this method, we also took images of a piece of filter paper with different content of water. Comparing the calculated result with the measured value by the electronic balance showed that our method has a good possibility to measure the water content of the relative thin materials with non-contact and non-invasive method from the THz imaging.

Gaps between the Expectations of People with Hearing Impairment toward Subtitles and the Current Conditions for Subtitle Creation in Japan

In this study, questionnaire surveys were conducted with film producers/directors and deaf and hard-of-hearing people to consider the issues surrounding subtitling of films for people with hearing impairment in Japan. The results show that only a small number of film producers taking part in this study have engaged in subtitling, and a majority pointed out the low profitability of producing subtitles under circumstances where the actual movie-viewing demand of hearing-impaired people is unclear. On the other hand, the survey of deaf and hard-of-hearing people revealed the actual movie-viewing tendencies of people with hearing impairment equal to that of hearing people and their high expectations regarding subtitles, despite limited opportunities to watch Japanese films in movie theaters. These results suggest possibilities of creating new economic models for increasing production and access to subtitles for hearing-impaired people sustainably.

Adaptation of Grouping Structure Analysis in GTTM to Hierarchical Segmentation of Dance Motion

In this paper, the authors propose the adaptation of the rules used in the grouping structure analysis in Lerdahl and Jackendoffs “A Generative Theory of Tonal Music (GTTM)” to dance motion analysis. The success of the adaptation realizes the segmentation of dance motion in a hierarchical fashion. The analysis method obtained by the trial of the above adaptation consists of the following procedures. A motion-capture data stream of a dance is first divided into a sequence of events by piecewise linear regression. The hierarchical structure of groups each of which consists of a sequence of the events is then extracted by applying the grouping rules adapted to dance motion analysis. The above method is applied to motion-data streams acquired by motion capture systems. The obtained results indicate the following advantages: (1) The structure of hierarchical segmentation is precisely extracted in response to the characteristic of an analyzed dance. (2) The extraction of the hierarchical segmentation provides the possibility of the development of a technique distinguishing the oversegmentation from regular boundaries. (3) The possibility of utilizing the information of hierarchical segmentation for the comparison of dance performances is suggested.

Extraction of Motion Characteristics in Dances by Statistical Analysis of Joint Motions

In this paper, the authors attempt to develop a technique for the analysis of the motions of dances having no stylized motion structure, focusing on joint motions. The variance-covariance matrix given by the statistical analysis of the time-series data of joint motions is selected for the evaluation index characterizing dance motions. The application of the derived evaluation index to the representation of dissimilarity between dances is shown to be effective when the whole commonness appearing in both the dances compared should be considered. It is also confirmed that the application of multidimensional scaling (MDS) with the orthogonal rotation of coordinate axes is effective to extract the distribution feature of a database of dances. The evaluation items characterizing all the dances belonging to the database are automatically extracted by the analysis of correlation between the coordinate axes given by MDS and the elements of the variance-covariance matrix.

Imaging of Epithelial Cancer in Sub-Terahertz Electromagnetic Wave.

We used sub-terahertz (THz) imaging to exam two cross sections of epithelial cancer tissue embedded in paraffin using a 0.19 THz electromagnetic wave. The sub-THz imaging system was constructed with a tunnel injection transit time (TUNNETT) diode, a Schottky barrier diode detector and a X-Z stage. We examined the difference between a sub-THz wave absorption in melanoma and nevus tissue

An Apparatus For Measuring Eye And Head Movements Using Ccd Image Sensor And 3space

New apparatus to measure the head and eye movements in real time has been developed. System is used as an instrument to diagnose vertigo patients. Eye movement is observed by a charge coupled device (CCD) image sensor camera. Motion of head is detected by 3SPACE ISOTRAK, of which working principle is measuring orthogonal magnetic fields. Data of three normal and three abnormal subjects including vertiginous persons have been acquired by the system.