The International Commission on Radiological Protection (ICRP) recommended the use of diagnostic reference levels (DRLs) for optimization of radiation protection of patients, and proposed choosing a percentile point as the initial value of the DRLs in the observed distribution of patient doses. This study was undertaken to survey the distribution of patient doses in our facility and to determine the local DRLs in intraoral radiography for optimization and quality control of dental X-ray examinations.
To obtain the patient entrance doses, background optical densities were measured on the periapical radiograph of adult patient incisors. The total 5,045 radiographs were extracted from the films (Carestream/Kodak UltraSpeed) for diagnostic X-ray examinations performed in the period May/1999-April/2000 using four intraoral X-ray units with half value layers from 1.5 to 2.0mm aluminum and three automatic processors under sensitometric control. The measured optical densities were converted into the patient entrance doses using the film characteristic curve.
The patient entrance doses were observed as a Gaussian distribution for the X-ray examinations of maxillary and mandibular incisors. The average patient entrance doses (±standard deviations) for maxillary and madibular incisors were respectively 1.27 ± 0.25mGy and 1.16 ± 0.24mGy corresponding to the optical densities of 2.59 ± 0.43 and 2.39 ± 0.42.
The average patient entrance doses for maxillary and madibular incisors were nearly equal to the values (1.3mGy and 1.1mGy) of Japan DRLs 2015. The local DRLs, remedial levels, and suspension levels useful for quality control of X-ray examinations were derived from the averages and standard deviations. However, to adequately optimize intraoral radiography, the newer higher sensitivity image receptors should be used for patient doses to achieve the lowest reasonable dose.

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As in the general population, peripheral artery disease (PAD) is reported to be closely associated with the onset of coronary artery disease (CAD) or stroke in hemodialysis patients. PAD has been suggested to be a strong prognostic factor of all-cause and CAD-related deaths in this population. We performed exploratory investigation of the factors associated with new-onset PAD in non-diabetic patients on hemodialysis. In our retrospective cohort study to explore the factors related to new-onset PAD, 106 non-diabetic outpatients undergoing maintenance hemodialysis with no signs of PAD at baseline (as confirmed by duplex ultrasonography examination of the lower extremity arteries) at a single dialysis unit were enrolled. Follow-up duplex ultrasonography examination of the lower extremity arteries was performed five years later to assess the presence or absence of PAD. Multivariate logistic regression analyses were employed to investigate which of the following covariates are associated with new-onset PAD: age, sex, smoking habit, hypo- High Dense Lipoprotein (HDL) cholesterolemia, and statin use. Findings on multivariate logistic regression analyses, with adjustments for potential confounding variables, demonstrated a significant relation between hypo-HDL cholesterolemia and new-onset PAD (odds ratio 1.91, 95%CI 1.11-3.34, p＝0.02). The present study suggested a possible association between hypo-HDL cholesterolemia and new-onset PAD in patients on hemodialysis.

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Recently, fetal endoscopic tracheal occlusion (FETO) has been reported to be beneficial for fetuses with congenital diaphragmatic hernia (CDH). A balloon occludes the trachea to retain pulmonary fluid and to force the lung to expand, which promotes the fetal lung to grow. However, balloon removal requires highly invasive surgical procedures which puts a burden on both mother and fetus. A minimally invasive procedure is needed. We examined the application of high intensity focused ultrasound (HIFU) as a means of trachea occlusion removal. The balloon was placed into a silicon tube in a water tank filled with degassed water. The balloon was inflated by injecting 0.5～1.0ml of Phase-Change Nanodroplet. HIFU was irradiated for 2 seconds, focusing on the back wall of the balloon under ultrasound guidance. In all cases, the balloon in the silicon tube ruptured. Also thermal denaturation in the silicon tube was seen. Although the utility of FETO has been reported, the removal methods have not been sufficiently discussed. HIFU might be suitable for clinical application technology for congenital diaphragmatic hernia. This study demonstrated that occlusion removal can be performed using this minimally invasive technique. In the future, we will carry out animal experiments to improve our HIFU system.

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Although CB units, many of which have been cryopreserved for long-term, are available for hematopoietic cell transplantation (HCT), it is not clear whether long-term cryopreserved CB tubes are representative of those CB units. The aim of this study was to evaluate whether long-term cryopreserved CB tubes are representative of those CB units; 110 CB units and CB tubes cryopreserved for more than 10 years, respectively, were analyzed. The CB units and CB tubes were thawed, and the number of total nucleated cells (TNCs), CD34＋ cells, viability rates, colony-forming units-granulocyte/macrophage (CFU-GM) cell counts, CD34＋CD38－ cells, and CD34＋CXCR4＋ cells were examined. The number of TNCs, CD34＋ cells, viability rates and CFU-GMs were 5.61±1.91×10⁸, 1.23±0.91×10⁶, 86.73±7.87%, 1.46±0.89×10⁵ for the CB units and 4.72±1.85×10⁸, 0.91±0.72×10⁶, 72.48±23.4%, 0.55±0.62×10⁵ for the CB tubes (p＜0.001, p＝0.0011, p＜0.001 and p＜0.001, respectively). All of those were significantly lower for the CB tubes than those of CB units. Interestingly, CFU-GMs were not determined in 42 (38.2%) CB tubes. Therefore each data from the CB units were compared between the group of CFU-GM detected and non-detected in the CB tubes. There were no significant differences between the groups. There was a positive relationship between the CB tubes and the CB units in the number of CD34＋ cells (r ＝ 0.747). Also there was a positive relationship between the number of CD34＋ cells in the CB tubes and CFU-GMs in the CB units (r＝0.345). These results indicate that the quality of the long-term cryopreserved CB tubes was decreased. In conclusion, the number of CD34＋ cells in the CB tubes predicts the quality of the CB units and may be used as a source for final quality control of the CB unit before transplantation.

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Propofol, a GABA agonist, a short-acting intravenous anesthetic agent, is widely used for anesthesia and sedation. In addition to its anesthetic effect, propofol shows a neuroprotective property on a nervous system under the ischemic state. It was reported that propofol suppresses program cell death, however, the mechanisms of the neuroprotection remain unclear. Autophagy is a homeostatic cellular mechanism for the turnover of organelles and proteins. During nutritional deficiency, autophagy promotes cell survival through the recycling of metabolic precursors. Furthermore, autophagy can regulate programmed cell death such as apoptosis and thereby influence disease pathogenesis. The aim of the present study was to clarify the molecular details of the neuroprotection with propofol against nutritional deficiency-induced autophagy and cell injury in SH-SY5Y cells. SH-SY5Y cells were cultured in serum-free medium to induce autophagy. Autophagic cells were treated with propofol (0.5µM, 1.0µM, 5.0µM) for 1-24 hours. Cytosolic Ca^2＋ (［Ca^2＋］_i), the specific marker of apoptosis (caspase-3 activity), and the biomarkers of autophagy (p62 and LC3-II) were analyzed. Furthermore, activities of c-jun N-terminal kinase (JNK) and AMP-activated protein kinase (AMPK) were measured. Nutritional deficiency-induced autophagic cells significantly decreased p62 and increased LC3- II, activities of caspase-3, AMPK and JNK. When SH-SY5Y cells were treated with propofol (1.0, 5.0µM), these biomarker were significantly suppressed. Furthermore, ［Ca^2＋］_i was decreased by treatment with propofol. ［Ca^2＋］_i reduction with propofol might have suppressed AMPK activity, and that prevented nutritional deficiency-induced autophagy. These results demonstrate that propofol at clinically relevant concentration suppressed the nutritional deficiency-induced autophagy and cell injury in neuroblastoma SH-SY5Y cells. Propofol prevented not only the neuroprotective property against oxidative stress and apoptosis but also autophagy-induced cell injury. This prevention may explain the pleiotropic effects of propofol that benefit the nervous system.

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To report our experience of the C1 lateral mass screw insertion technique (Goel & Harms) with navigation in posterior upper cervical fixation. The disorders were odontoid fractures. C1 lateral mass screws were positioned using the technique with navigation. The trajectory of the screw insertion was determined according to 4 paired points. The screw hole was drilled with a 2mm diamond bar, and then 3.5mm polyxial screws were inserted directly into the lateral mass. The C1 and C3 screws were connected with the rods. Iliac bone grafting was also done. C1 screws were placed without incident, using the 4 paired points method. Our technique of C1 lateral mass screw insertion is useful for posterior upper cervical fixation.

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