Lidocaine hydrochloride and alkalinized lidocaine hydrochloride solutions were filled in en­ dotracheal tube cuffs to determine the rate of diffusion of lidocaine across the cuffs, and assess the usefulness of these cuffs as a drug delivery system. Mallinckrodt^TM Oral RAE^® tracheal tubes were filled with three different lidocaine solutions, i.e., mixtures of 4% lido­ caine hydrochloride solution and distilled water, 4% lidocaine hydrochloride solution an 8.4% sodium bicarbonate solution (LSB­Gr), and 4% lidocaine hydrochloride solution and dipotassium phosphate solution (LDP­Gr). Cuffs filled with the relevant lidocaine solution were placed in beakers filled with distilled water. A 100 μL sample of the water in the vessel was taken from each beaker every 30 minutes for 360 minutes to determine the concentra­ tion of lidocaine diffused across the cuff using fluorescence polarization immunoassay.The cuff surface was observed after 60, 180, and 360 minutes of exposure for changes in the structure of the material. Lidocaine in LSB­Gr and LDP­Gr diffused across the cuffs at 30 minutes of exposure and thereafter. The lidocaine concentration in water in the vessel was 133.8 μg/mL for LSB­Gr, and 119.0 μg/mL for LDP­Gr. Although the cuffs did not rup­ ture during exposure, the cuff material deteriorated over time. The results indicate that alka­ linization of intracuff lidocaine increases the rate of diffusion of lidocaine across the en­ dotracheal tube cuff and affects the cuff material, which increases the risk of complications due to cuff rupture. (J Osaka Dent Univ 2016 ;50 : 1−6)

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Age estimation is an important step in the identification of remains such as putrefied, skeletal, and burned bodies. From these bodies, the maxilla and mandible, along with teeth, often remain and are therefore commonly used for age estimation. However, reports indicate that the estimated age differs as a result of subjective judgments made when using various age estimation methods. In addition, the mandibular angle has been reported to increase with age. There have been some reports of age estimation from mandibular angle in children,but, to our best knowledge, there have been no reports in adults in the field of forensic odontology. We designed a new age estimation method based on the measured mandibular angle and oral findings (e.g., the numbers of remaining and treated teeth) from three-dimensional computed tomography images, using the following formula : estimated age＝0.6×(mandi bular angle) −0.7×(number of remaining teeth) −0.3×(number of treated teeth). In a comparative analysis, age was found to correlate positively with the mandibular angle and negatively with the numbers of remaining and treated teeth. The overall age estimation error with this method was 7.4 ± 5.4 years. No significant differences were observed with respect to sex. (J Osaka Dent Univ 2016 ;50 : 7-11)

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Although it is thought that orthodontic treatment should be avoided in patients with diabetes mellitus, as the number of these patients increases, treatment may become necessary for some of them. We experimentally moved the teeth using theWaldo method in Goto-Kakizaki (GK) rats, an animal model of type II diabetes. On days 1, 3, 5 and 7 after initiation of tooth movement, we extracted three upper molars and the surrounding periodontal tissue en bloc, and measured the movement distance between the first (M1) and second (M2) molars. We also measured the distance between the dental crowns of the three teeth from themesial of M1 to the distal of the third molar (M3). Afterward we made histopathologic observations.Although measurements of tooth movement and inter-crown distance from M1 to M3 showed large values on the first day after initiation of the procedure in the control group, these measurements subsequently did not change. Histopathologically, there was dilation of the periodontal ligament capillaries on the tension side on post-procedure day 1 in both the control and experimental groups. On the pressure side, marked capillary dilation was seen on post-procedure day 5 in the controls and post-procedure day 3 in the experimental group. From post-procedure day 3 the course of the collagen fibers was disrupted in the experimental group and the stainability with silver impregnation staining increased compared with the controls. Thus, in the diabetic rats there was decreased metabolic function, blood supply, and ability to form multinucleated giant cells, and the structure of collagen fibers in the connective tissue was changed. The above suggests that time is required for toothmovement in diabetes and that there is a possibility of marked breakdown of periodontal tissue. (J Osaka Dent Univ 2016 ; 50 : 13-21)

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Based on algorithm differences between aperiodic and power spectrum analysis of the electroencephalogram (EEG), we hypothesized that the effects on the EEG of an antiepileptic drug would be equally well detected with either lidocaine-induced seizure by aperiodic analysis or by power spectrum analysis. However, the former is superior.EEG activity was recorded in anesthetized rabbits prior to intravenous infusion of valproic acid and lidocaine and after the onset of EEG activity. Values for delta, theta, alpha, beta, and total activity, as well as edge frequency were compared within each group, and were expressed as percent change from baseline for comparison between aperiodic and power spectrum analysis. With valproic acid, EEG changes were modest and the two methods of EEG analysis were significantly different from one another for only two of the 12 comparisons. With lidocaine, the lidocaine-induced seizure activity was associated with widespread EEG changes which were better detected by aperiodic analysis than by power spectrum analysis. Comparison between the two methods of analysis indicated significant differences for theta, alpha, and beta activity and edge frequency. These results indicate that both methods of analysis may be suitable to detect modest drug-induced EEG changes, whereas aperiodic analysis is superior for detection of widespread seizure activity. (J Osaka Dent Univ 2016 ; 50 : 23-29)

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Platelet-rich plasma (PRP) promotes early tissue healing and regeneration, and significantly induces proliferation of various cells. We investigated how PRP affects the proliferation of human synovial cells, which is not well understood. Surgical specimens of synovium were digested and the liberated cells resuspended in Dulbecco's modified Eagle's medium (DMEM). PRP was prepared using the double spin method, and activated PRP (aPRP) was prepared with calcium chloride and autologous thrombin. Cell proliferation was examined using Cell Counting Kit-8 (Dojindo Molecular Technologies, Gaithersburg, MD, USA) and the protein concentrations of IL-6 and IL-8 in culture media were determined using the Artemis TR-FRET Microplate Reader for HTRF® (Cosmo Bio, Tokyo, Japan) with HTRF® reagents (Cisbio, Marcoule, France). We found that aPRP promoted proliferation of human synovial cells more than did PRP on day 5 of culture and that it promoted proliferation in a concentrationdependent manner. Proteins of IL-6 and IL-8 were up-regulated in culture media. 5% aPRP was the lowest relative value per cell among IL-1β , -6 and -8. Thus, we determined an optimal concentration of 5%. (J Osaka Dent Univ 2016 ; 50 : 31-35)

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We investigated the exposure concentration of isopropyl alcohol, which is used for disinfection at the time of intravenous catheterization, in the breathing zone. This study examined the concentration of isopropyl alcohol for disinfection as part of intravenous catheterization, and confirmed that medical workers are unlikely to inhale isopropyl alcohol at concentrations that may lead to health hazards during normal disinfection. (J Osaka Dent Univ 2016 ; 50 : 37-39)

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Acantholytic squamous cell carcinoma (ASCC) is a rare variant of squamous cell carcinoma (SCC) that has a poorer prognosis than other forms of SCC. However, few studies have been reported on the biological nature of ASCC. We did an immunohistochemical study on ASCC in the head and neck region using 6 samples each of SCC and ASCC obtained from Osaka Dental University Hospital and Kishiwada City Hospital. We also studied the immunohistochemical expression of Ki-67, E-cadherin and α-catenin. For ASCC, the labeling index (LI) of Ki-67 was significantly increased compared with SCC (p<0.01). The expression of α-catenin and E-cadherin were significantly reduced for ASCC compared with SCC (p<0.05). Patients with ASCC in the head and neck region who had less tumor adhesion and higher growth factor levels had a poorer prognosis than those with SCC, as determined immunohistochemically. (J Osaka Dent Univ 2016 ; 50 : 41-45)

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We used magnetic resonance imaging (MRI) to clarify whether autologous blood injection (ABI) is an effective treatment for chronic recurrent dislocation of the temporomandibular joint (TMJ). MRI examination was performed 1 hour and 12 weeks after ABI for 14 patients with chronic recurrent TMJ dislocation. Three types (I-III) of patients were identified based on MRI. Type I showed findings similar to joint effusion in the TMJ capsule. Type II showed a scattering of T2-weighted signal hyperintense regions around the TMJ capsule. Type III showed changes in the position of the condyle during mouth opening. Suppression of chronic recurrent TMJ dislocation was very strongly related to Type III findings. Three important findings were evident based on MRI after treatment for chronic recurrent temporomandibular joint dislocation with ABI into tissue surrounding the TMJ capsule. Injection of autologous blood into the region around the TMJ capsule appears important for achieving a favorable suppression of dislocation. (J Osaka Dent Univ 2016 ; 50 : 47-53)

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