[en] The mean number of nucleoli in a cancer cell is 1.51, which is apparently larger in number than that in a normal cell (1.17), although there are slight differences in number by the histological types of cancer. Although there are slight differences in the location and shape of nucleoli between the histological types of cancer, they resembles those of normal cells in shape and location (the nucleoli are located in the center, and circular or circuloid in shape). The size of nucleoli is 1.58 times larger than that of normal cells both by histogram and by mean values. According to the histological classification, the nucleoli of keratinized large cells were more enlarged than those of undifferentiated small cells. As for the change in the number of nucleoli due to irradiation, the tendency to increase in number began to be noted with 500 rads irradiation, and becomes more remarkable with the increase of dose. Especially, it is observed more often in small cell carcinoma than large cell carcinoma. No remarkable change was observed in their location and shape with 1,000 or less rads. However, with about 2,000 rads nucleoli tended to be irregular in shape. There was a tendency of increasing in size with 2,000 rads, on histogram and mean values. Therefore, the change of nucleoli consists of the increase in number and swelling. This fact is important in radiation pathology as well as in the diagnosis of radiosensitivity. (N. Kanao)

[en] In our proposed method of the completely electrodeless electric propulsion system, a high-density (∼ 10"1"3 cm"-"3 ) helicon plasma is accelerated by the Lorentz force, i.e., the product of the azimuthal current j_θ and the radial component of magnetic field B_r. In order to promote the plasma acceleration scheme, we used permanent magnets (PMs) designed to increase B_r in comparison to the present electromagnets (EMs). As an initial try of the plasma acceleration by our system, electron density n_e and ion velocity v_i of generated plasma using PMs' magnetic field were measured, and we have obtained the maximum value of n_e = 2.5 × 10"1"2 cm"-"3 and v_i = 2.2 km/s. In addition, we have also introduced a combined, flexible operation of using PMs and EMs leading to better plasma performance. (author)

[en] In order to establish a completely electrodeless electric thruster, we have been studying the proposed electromagnetic acceleration methods, and estimating plasma performance using various diagnostics. Plasma thrust is the most important feature of the thruster; therefore estimation of the plasma thrust is necessary. In this study, we have developed a pendulum-target-type plasma thrust stand. Our experiment uses a Large Mirror Device and a high-power radiofrequency source (7 MHz, ∼5 kW) to produce high-density helicon plasma. The thruster uses both permanent magnets and electromagnets for generating magnetic field with a large radial component to increase electromagnetic acceleration by the proposed method of including an azimuthal current. In this paper, details of the developed thrust stand and experimental results for thrust, thrust efficiency and specific impulse are presented. (author)

[en] Monitoring and protecting of occupational eye doses in interventional radiology (IR) are very important matters. DOSIRIS™ is the useful solution to estimate the 3 mm dose-equivalent (Hp(3)), and it can be worn behind lead glasses. And DOSIRIS™, adjustable according to 3 axes, it is ideally placed as close to the eye and in contact with the skin. So, DOSIRIS™ will be suitable eye lens dosimeter. However, the fundamental characteristics of the DOSIRIS™ in the diagnostic x-ray energy domain (including that of IR x-ray systems) remain unclear. Here, we evaluated the performance of the dosimeter in that energy range. As a result, the DOSIRIS™ has good fundamental characteristics (batch uniformity, dose linearity, energy dependence, and angular dependence) in the diagnostic x-ray energy domain. We conclude that the DOSIRIS™ has satisfactory basic performance for occupational eye dosimetry in diagnostic x-ray energy settings (including IR x-ray systems). (note)

[en] Pharyngo-esophageal stricture occurs as an adverse event after chemoradiation therapy for head and neck cancer, although complete obstruction is rare. The patient's quality of life is impaired due to the difficulty in food intake and in swallowing saliva. Endoscopic balloon dilatation and stent insertion have been used for their treatment, but there is still no consensus on the optimal treatment. We report a case in which we were able to release the obstruction by inserting an endoscope through the mouth and the gastrostomy. The patient, a 47-year-old man, was diagnosed as having Stage III squamous cell carcinoma of the mesopharynx (T4N1M0). Because the result of induction chemotherapy was SD (stable disease), we performed tumor resection and administered postoperative chemoradiation therapy. Gastrostomy was performed because swallowing dysfunction was observed at the completion of the post operative radiation sessions. One year later, while imaging studies showed no recurrence of the disease, the swallowing function had not improved at all. We conducted video fluorography and gastroscopy to determine the cause, and detected pharyngo-esophageal obstruction. We attempted to release the obstruction endoscopically in the hope of preserving the vocal functions. We chose to use a dual approach via the mouth and the gastrostomy. The adhesion site of the pharynx and the esophagus was incised with a hook knife while observing from the gastrostomy side. The adhesions were dissected and the proximal and distal sides were opened. Balloon dilatation training was undertaken after the operation. The patient is now able to take liquids and semi-solid foods orally, but nutrition via the gastrostomy was continued. Clearing the obstruction did not completely resolve the dysphagia and treatment of the velopharyngeal insufficiency was necessary in this case. Therefore, the choice of treatment should be based on the wishes of the patient, clinical situation, and the nature of the treatment for the primary disease. (author)

[en] We often measure both the dose and dose rate of scattered radiation when evaluating occupational exposure. However, no studies have emphasized the need to consider the energy of the scattered radiation. The conventional apparatus for taking energy measurements, X-ray spectrometers, are not easy to handle. Recently, the X2 survey meter that can measure both the dose and mean energy of scattered radiation was offered by Unfors RaySafe. However, no detailed the fundamental performance on mean energy of the X2 survey meter. Therefore, this study evaluated the fundamental performance of X2 survey meter in comparison to CdTe spectrometer. As a result, the X2 survey meter had a similar response to the CdTe spectrometer. Furthermore, the X2 survey meter has advantages that the sensor is small, the measured value is obtained immediately. We concluded that the X2 survey meter facilitates accurate monitoring of the scattered radiation. (author)

[en] It is important to measure scattered radiation in diagnostic radiology in terms of evaluation of occupational exposure and leakage radiation dose. Recently, Unfors RaySafe (Sweden) released a solid-state survey sensor aimed at expanding RaySafe X2 system. However, there are no detailed reports regarding the performance, which includes energy dependence and angular dependence, of X2 survey meter. The purpose of this study was to evaluate the performance of X2 survey meter. Experiments were conducted to compare the performance of X2 survey meter with that of an ionization chamber survey meter. The results showed that the fundamental performance of X2 survey meter were equal to or superior to that of an ionization chamber survey meter. In addition, X2 survey meter is easy to handle. The study concludes that X2 survey meter has adequate performance for measurement of scattered radiation in diagnostic radiology. (author)

[en] Abnormal DNA methylation at the C-5 position of cytosine (5mC) of CpG dinucleotides is a well-known epigenetic feature of cancer. Levels of E-cadherin, which is regularly expressed in epithelial tissues, are frequently reduced in epithelial tumors due to transcriptional repression, sometimes accompanied by hypermethylation of the promoter region. δEF1 family proteins (δEF1/ZEB1 and SIP1/ZEB2), key regulators of the epithelial-mesenchymal transition (EMT), suppress E-cadherin expression at the transcriptional level. We recently showed that levels of mRNAs encoding δEF1 proteins are regulated reciprocally with E-cadherin level in breast cancer cells. Here, we examined the mechanism underlying downregulation of E-cadherin expression in three basal-type breast cancer cells in which the E-cadherin promoter region is hypermethylated (Hs578T) or moderately methylated (BT549 and MDA-MB-231). Regardless of methylation status, treatment with 5-aza-2′-deoxycytidine (5-aza), which inhibits DNA methyltransferases, had no effect on E-cadherin expression. Knockdown of δEF1 and SIP1 resulted in recovery of E-cadherin expression in cells lacking hypermethylation, whereas combined treatment with 5-aza synergistically restored E-cadherin expression, especially when the E-cadherin promoter was hypermethylated. Moreover, δEF1 interacted with DNA methyltransferase 1 (DNMT1) through the Smad-binding domain. Sustained knockdown of δEF1 family proteins reduced the number of 5mC sites in the E-cadherin promoter region, suggesting that these proteins maintain 5mC through interaction with DNMT1 in breast cancer cells. Thus, δEF1 family proteins appear to repress expression of E-cadherin during cancer progression, both directly at the transcriptional level and indirectly at the epigenetic level