Bladder cancer has been observed in patients after permanent iodine-125 brachytherapy （hereafter referred to as brachytherapy） for prostate cancer. We investigated secondary bladder cancer after brachytherapy. From January 2005 to March 2021, a total of 1,478 patients underwent brachytherapy for localized prostate cancer at Showa University Hospital and Showa University Koto Toyosu Hospital. A standardized incidence rate was calculated from the incidence of secondary bladder cancer after brachytherapy and compared with the national cancer registry general incidence data. The median follow-up was 4.7 years. Secondary bladder cancer occurred in 15 of 1478 patients （median age: 71 years）. The incidence was 198 cases/100,000 persons/year. The incidence was 2.84 times higher than that of Japan’s national cancer registry. In addition, as a characteristic of secondary bladder cancer, the malignancy tended to be high regardless of the depth of invasion. The relative risk between cases with a secondary bladder cancer period until occurrence of ＞5 years and cases with a secondary bladder cancer period until occurrence of ≤5 years was 1.61 times （95％ CI: 0.57-4.50）, but the difference was not significant. In this study, we found that the incidence of bladder cancer was 2.84 times higher than that of the general population of Japan, suggesting that brachytherapy increases the risk of developing bladder cancer. To our knowledge, this study is the first to compare the incidence of brachytherapy and general bladder cancer in Japan. The results of this study suggest that although brachytherapy is effective for prostate cancer, attention should be paid to the early detection of bladder cancer because of the risk of secondary cancer development.

View full abstract

Three-dimensional imaging may aid in complementing intraoral and panoramic radiography during the diagnosis of tooth eruption disturbances. The purpose of this study was to investigate teeth affected by eruption disturbances in patients referred for cone-beam computed tomography （CBCT）. The analysis included 134 teeth in 113 patients ＜20 years of age who demonstrated tooth eruption disturbances （excluding wisdom teeth） and were referred for CBCT imaging. Factors analyzed included: （1） the types of teeth affected by eruption disturbances; （2） distribution of eruption disturbances by age and gender; （3） CBCT image findings; and （4） treatment plan and prognosis. The analysis included 126 permanent and eight deciduous teeth. The maxillary canines were the most frequently affected （44 teeth, 32.8％）, followed by the maxillary central incisors （23 teeth, 17.2％）. The most typical etiological factors discovered through the CBCT images were abnormalities in the position and direction of the teeth （66 teeth, 49.3％）, followed by the presence of cysts and benign tumors （28 teeth, 20.9％） and supernumerary teeth （16 teeth, 11.9％）. Treatment included removal of the cause and implementation of treatment measures such as fenestration-traction. The outcomes of this research conformed with prior evidence concerning the causative factors of eruption disturbances and the distribution by types of teeth. CBCT imaging has considerably contributed to enhancing the quality of medical care via three-dimensional evaluation of the condition of different teeth affected by eruption disturbances and their subsequent management.

View full abstract

Dental implant prosthetics are extensively used as replacement for missing teeth in patients. However, interproximal contact loss between the implant and the tooth has been reported by several studies. Because the implants are osseointegrated and remain immobile within the bone, wear of the adjacent teeth may impair the contact between the implant and the tooth. Contact gauges are commonly used for examination of the interdental separation in natural dentition; however, the effectiveness of such gauges in the examination of implants fuzed to the bone in the absence of a periodontal ligament remains unclear. This study aimed to conduct subjective and objective evaluations on the interdental separation in human teeth using fabricated simulation models （implant-implant, natural tooth-implant, and natural tooth-natural tooth） and contact gauges. Although a deviation of approximately 0.5 N was observed in the frictional force between the implants and the natural teeth during the objective evaluation, there were no significant differences in the subjective evaluation. The models and methods used in this study may facilitate the prediction of frictional forces under various clinical conditions, including those that accelerate contact loss. To confirm the findings of this study, additional in vivo studies need to be conducted.

View full abstract

The identification of corpses is according to physical characteristics. Among these, teeth are often used for personal identification because they are insusceptible to post-mortempostmortem alterations. Recently, different types of digital data, like optical impressions, have been employed in dentistry. This research identified three indices on the teeth of Standard Triangled Language （STL） data collected using optical impression-taking and evaluated the possibility of personal identification by examining the area of the triangle obtained from three indices. STL data generated from intraoral plaster models （n＝140） were fabricated virtual antemortem （VAM） data. STL data collected directly from the intraoral cavity （n＝24） were employed as virtual post-mortempostmortem （VPM） data. Three indices were identified for each first premolar, second premolar, and first molar. Two techniques were devised to find the three points. The area of the triangle created utilizing the three measurement points were employed to assess the conditions under which each VPM data could be excluded from the VAM data group. Although no significant difference existed between the two techniques, one method was preferred for screening. Optimal conditions for both methods were screening carried out with two teeth, including the second premolar. In both methods, only the individual was screened out of 140 individuals when the second premolar was added in the two-teeth condition. This study demonstrated the possibility of personal identification by assessing the area obtained using three measurement points on teeth as indices, indicating a potential application in forensics in the future.

View full abstract

Cone-beam computed tomography （CBCT） is frequently used for preoperative examination of implants; however, it cannot be used to determine the bone mineral density （BMD） owing to its incapability at providing the CT values obtained through a CT scan. An efficient and accurate technique for measuring BMD using CT is quantitative CT （QCT）. Herein, we examined whether jaw bone mineral content can be easily estimated from the CBCT gray value by applying the QCT method. Two CBCT systems, a 3DX multi-image microCT （3DX） and a KaVo 3D eXam （KaVo）, were used. Three dry human skull bones with calibration phantoms on the skin side and a target phantom on the intraoral side were used. For 3DX, X-ray tube voltage was altered to investigate the effect of exposure conditions on the grey value. The bone density （calcium carbonate density） and calibration phantom gray value were used to generate a conversion curve to estimate the bone density of the target phantom, and subsequently, the error from the true value was calculated. Errors were in the range of approximately 5％-15％ and 3％-4％ for 3DX and KaVo, respectively. KaVo, which has a wider irradiation field, yielded better results than 3DX. 3DX demonstrated smaller errors at higher tube voltages when the tube voltage was varied. Although the error differed depending on the device, CBCT could be used for the estimation of the approximate bone density of the implant site despite the error.

View full abstract

Although （i） spinal cord disinhibition can cause spontaneous burst activities in the phrenic nerve and （ii） this propriospinal network can be harnessed to allow diaphragm function after a spinal cord injury, the characteristics of this network are unclear. To characterize this network, we cut the isolated spinal cord from neonatal rats aged 0-4 days into four blocks consisting of three spinal segments （C3-C5, T6-T8, L2-L4, and L6-S2）, and motor activities were recorded from C4, T7, L3, and S1 ventral roots （VRs）. Under control conditions, few spontaneous activities occurred in all VRs. When 10-µM strychnine （a broad antagonist of glycine and GABAA receptors） was applied, spontaneous burst activities were observed in all VRs, suggesting that a burst-generating network （BGN） exists in each segment. In spinal cord preparations from segments C3 to S2, local application of strychnine to the C3-C5 segments resulted in spontaneous bursts concurrently in not only the C4VR but in all other VRs. In spinal cord preparations, repetitive electrical stimulations to the phrenic afferent evoked burst activities in not only the phrenic nerve but also in other C4 and C5 spinal nerves under strychnine. In the C3-C5 block preparation, phrenic afferent stimulation failed to evoke burst activities in the phrenic motor nerve, whereas C4 spinal afferent stimulation evoked burst activities in not only the C4 and C5 spinal nerves but also in the phrenic motor nerve. Thus, it is difficult to specifically activate the BGN for the phrenic nerve in the neonatal rat spinal cord by local disinhibition of C3-C5 segments or by phrenic afferent stimulation.

View full abstract

Carotid artery stenting （CAS） is a procedure used in the treatment of internal carotid artery stenosis, a condition that can lead to cerebral infarction. Cerebral hyperperfusion syndrome is among the post-CAS complications. Thus, to ensure postoperative control, understanding the cerebral blood flow is warranted. Nuclear medicine scan is used for the quantitative assessment of cerebral blood flow; however, since magnetic resonance imaging allows assessment of the cerebral artery, it is often used pre- and postoperatively. In the present study, we compared magnetic resonance angiography （MRA） with nuclear medicine scan to determine if MRA can delineate the cerebral blood flow in patients with CAS. The correlation coefficient between the predicted regional cerebral blood flow obtained from MRA and 123I-IMP was 0.68. Moreover, the concordance rate was high. As a result, the MRA test may be used as an alternative imaging study, and it was found to be a reference value in clinical practice.

View full abstract

Endocan expression has been associated with aggressive tumor progression and poor outcomes in various cancers. Our preclinical study demonstrated that endocan in the peripheral blood has the potential for use as a prognostic biomarker of triple-negative breast cancer （TNBC）. Currently, the clinical results of endocan in the blood collected from patients with breast cancer are extremely limited. Thus, this study aimed to examine the extent to which blood endocan correlates with the staging of cancer in such patients. A total of 54 patients with confirmed breast cancer who were treated at Showa University Hospital between 2020 and 2021 were included in this study. Blood was obtained from them, and the endocan level in plasma samples was measured using a commercial ELISA kit. The correlation between blood endocan level and clinicopathological characteristics was then determined. The higher the cancer staging, the higher the positivity rate of endocan in patients with luminal-type breast cancer, although no significant association was observed. The positivity rates of endocan at stages 0 and I were 17％ and 38％, respectively. However, no positivity was observed for serum carcinoembryonic antigen （CEA） or cancer antigen 15-3 （CA15-3）, indicating that endocan could be more sensitive than the frequently used tumor markers. The patient database demonstrated that the ESM1 gene expression was significantly higher at any stage in breast tumor tissue than in normal breast tissue. This study suggests that endocan is a potential candidate for a new, blood-based biomarker for breast cancer.

View full abstract