The Association between Anthropometric Indices of Obesity and Chronic Kidney Disease in Middle-aged Japanese Men and Women: A Cohort Study

Objective This study investigated associations between three indices of obesity-the body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR)-and the incidence of chronic kidney disease (CKD). Methods The employees of a company in Japan (1,725 men, 1,186 women; aged 35-55 years) had BMI, WC, and WHtR measured in health examinations. The incidence of CKD was determined at annual medical examinations over a six-year period. The hazard ratios for CKD were calculated using proportional hazard models, and the χ² statistic was used to compare the strengths of the associations. Results The mean BMI (kg/m²), WC (cm), and WHtR were 23.6, 84.3, and 0.49 for men and 22.3, 79.7, and 0.50 for women, respectively. The incidence of CKD (/1,000 person-years) was 18.1 for men and 8.4 for women. In men, positive linear associations were observed between the BMI, WC, and WHtR and the risk of CKD, even after adjusting for the presence of metabolic abnormalities (p for trend <0.001, 0.012, and 0.023, respectively). In women, a linear association was observed only between the WHtR and CKD, not the BMI or WC (p for trend =0.042, 0.057, and 0.186). The χ² statistics were the highest for the BMI in both men and women. Conclusion The BMI, WC, and WHtR were linearly associated with the risk of CKD independently of metabolic abnormalities in men, while the associations were weaker or not significant in women. The BMI was the most strongly associated with the incidence of CKD in both men and women.     

Tumor‐suppressive microRNA‐1291 directly regulates glucose transporter 1 in renal cell carcinoma

Our recent studies of microRNA (miRNA) expression signatures demonstrated that microRNA‐1291 (miR‐1291) was significantly downregulated in renal cell carcinoma (RCC) clinical specimens and was a putative tumor‐suppressive miRNA in RCC. The aim of the present study was to investigate the functional significance of miR‐1291 in cancer cells and to identify novel miR‐1291‐mediated cancer pathways and target genes in RCC. Expression of miR‐1291 was significantly downregulated in RCC tissues compared with adjacent non‐cancerous tissues. Restoration of mature miR‐1291 in RCC cell lines (A498 and 786‐O) revealed significant inhibition of cell proliferation, migration and invasion, suggesting that miR‐1291 functioned as a tumor suppressor. To identify miR‐1291‐mediated molecular pathways and targets, we used gene expression analysis (expression of RCC clinical specimens and miR‐1291‐transfected A498 cells) and in silico database analysis. Our data demonstrated that 79 signaling pathways were significantly regulated by tumor‐suppressive miR‐1291 in RCC cells. Moreover, solute career family 2 member 1 (SLC2A1) was a candidate target of miR‐1291 regulation. The SLC2A1 gene provides instructions for producing glucose transporter protein type 1 (GLUT1). Luciferase reporter assays showed that miR‐1291 directly regulated SLC2A1/GLUT1. In RCC clinical specimens, the expression of SLC2A1/GLUT1 mRNA was significantly higher in cancer tissues than in non‐cancerous tissues. A significant inverse correlation was recognized between SLC2A1/GLUT1 and miR‐1291 expression (r = ?0.55, P < 0.0001). Loss of tumor‐suppressive miR‐1291 enhanced RCC cell proliferation, migration and invasion through targeting SLC2A1/GLUT1. The identification of novel tumor‐suppressive miR‐1291‐mediated molecular pathways and targets has provided new insights into RCC oncogenesis and metastasis.     

Occlusal contacts during lateral excursions in children with primary dentition

The presence of non-working occlusal contacts in adults is considered abnormal and may initiate parafunctional activity. Few studies have looked for non-working occlusal contacts in children with primary dentition. The purposes of this study were (1) to prove the existence of non-working-side occlusal contacts, and (2) to quantify their area during lateral excursion in children with primary dentition. To achieve this purpose, we developed a measurement system that combined a tracking system for mandibular movements with a three-dimensional digitizer for tooth shape. Ten children were selected for this study. Estimated occlusal contact area of the primary second molar on the non-working side was 0.8 mm2, in contrast to 2.0 mm2 on the working side, at 3.0 mm of movement of the lower incisor. All children examined had some occlusal contacts on the non-working side during the first part of lateral excursion.     

A calculation method for the range of occluding phase at the lower incisal point during chewing movements using the curved mesh diagram of mandibular excursion (CMDME)

The purpose of this study was to develop a method for calculating the range of the occluding phase in chewing movements. In this study, we defined 'range' as the distance of the movement at the lower incisal point while the mandible moves with tooth contact. First, mandibular excursions were measured using an opto-electronic movement analysis system, which can measure mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. With use of this measurement data, the curved mesh diagram of mandibular excursion (CMDME) previously reported was made. Then, chewing movements were measured using the same analysis system. The movements were separated into their component chewing cycles. Finally, we calculated the distance between each cycle and the CMDME. The occluding range of our subject was 0.4 mm at the closing phase and 3.4 mm at the opening phase. These results suggest that tooth contact occurs during chewing movement and demonstrate that the range of the occluding phase for the opening and closing phases of a subject can be calculated without morphological data from a dental cast.     

Service-mix in general dental practice in Japan: A survey in a suburban area

Overseas investigations have reported the amount and variety of dental services provided. An understanding of the current service-mix in private general practice is important in the anticipation of the future practice of dentistry. The main purpose of this study was to describe the service-mix of private general practitioners in Japan, which was recorded using the Australian Dental Association Dental Procedure Code. Some comparisons with previous studies were offered. The youngest age group and adolescents formed only a small percentage of the total patients, while the greatest percentage of patients occurred in the 45–64 year age group. The services provided were mainly restorative, diagnostic, advanced restorative and endodontic services. Preventive services represented a minority of dental activity, especially for young patients. Periodontic and orthodontic services were also remarkable for their low percentage in all age groups. In comparison with an Australian study, the percentage of preventive services was considerably lower. Movement toward a preventive emphasis in Japanese dentistry requires a change in the clinical model, de-emphasizing biomedical and aetiological approaches and placing greater emphasis on the patient and factors affecting dental practice.     

Influence of adhesive application duration on dentin bond strength of single-application bonding systems

This study examined the relationship between the bond agent application duration and the dentin bond strength of several single-application bonding systems. The restorative material/ bonding systems used were Reactmer, with its single-application bonding system Reactmer Bond (RB, Shofu Inc, Kyoto, Japan); Palfique Estelite, with its single-application bonding system One-Up Bond F (OU, Tokuyama Co, Tokyo, Japan) and F2000 Compomer, with its bonding system Primer/Adhesive in Clicker (F2,3M Dental Products, St Paul, MN 55144, USA). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied for 5, 10, 20, 30 and 60 seconds, and restorative materials were condensed into a Teflon mold (04 x 2 mm) on the dentin and light activated. Fifteen samples per test group were stored in 37 degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Duncan test (p = 0.05) was done. SEM observations of the treated dentin surface were also conducted. The dentin bond strength ranged from 6.9 +/- 2.4 to 11.2 +/- 2.8 MPa for RB, 8.9 +/- 2.2 to 12.2 +/- 1.9 MPa for OU, and 7.8 +/- 3.1 to 11.4 +/- 2.6 MPa for F2. No significant differences were found among the 10-60 second application duration groups for the systems used. From the SEM observations, demineralization of the dentin surface was more pronounced with longer application duration. The data suggest that the duration of single-application bonding systems was not a crucial factor for determining dentin bond strength, even though morphological changes were observed on the dentin surface.     

Actinomycosis originating in the submandibular gland: Report of a case

We report herein a very rare case of actinomycosis originating in the submandibular gland in which malignancy was suspected. A 56-year-old man visited our clinic with a chief complaint of painless mass in the right submandibular region. From the imaging diagnosis, we suspected malignant tumor in the submandibular gland. Under general anesthesia, right radical neck dissection and excision of the submandibular gland with the above mass were carried out. Histopathological diagnosis of actinomycosis in the submandibular gland was made. Because the focus exists within the gland, we consider this case as a primary submandibular gland actinomycosis. Two years postoperatively, the tumor has not recurred. On diagnosis, it is necessary to differentiate this disease with other benign or malignant tumors.     

Fatigue and damage to the masseter muscle by prolonged low-frequency stimulation in the rat

This study aimed to examine peripheral fatigue and the resultant damage to the masseter muscle due to prolonged low-frequency stimulation. Thirty male rats were divided into S1, S2, S4, Dantr and Sham groups. The left masseters were used as experimental muscles. A pair of stimulation electrodes was placed on the left masseter. A stimulating session included rectangular electric pulses of 18 Hz (5 mA, 18 V, 0.7 ms) for 2 h with a 3 min rest period between sessions. One session was given to the S1 group, two sessions to the S2 group and four sessions to the S4 group. Four sessions were given to the Dantr group with administration of dantrolene to determine any artifacts of the electrical current. No electric stimulation was given to both side masseters in the Sham group or to the control (right) masseters in the other groups. In each session, jaw-closing force increased to a peak within 1 min and attenuated to the steady force. The peak force decreased as the session advanced in each group. Both side masseters were dissected after the stimulations and examined histologically. The experimental masseter was significantly heavier than that of the controls in the S1, S2 and S4 groups, and the muscle fibres showed irregularity of size and shape with enlargement of interstitial space and infiltration of mononuclear cells into the fibres. However, no such histological change was observed in the Dantr and Sham groups. It was confirmed that fatigue and damage to muscle fibres could be induced in masticatory muscles by prolonged low-frequency stimulation.