Yunn-Jy Chen

Epigallocatechin‐3‐gallate diminishes CCL2 expression in human osteoblastic cells via up‐regulation of phosphatidylinositol 3‐Kinase/Akt/Raf‐1 interaction: A potential therapeutic benefit for arthritis

OBJECTIVE To assess the effects of epigallocatechin-3-gallate (EGCG) on oncostatin M (OSM)-induced CCL2 synthesis and the associated signaling pathways in human osteoblastic cells. The therapeutic effect of EGCG on collagen-induced arthritis (CIA) in rats was also studied. METHODS CCL2 and c-Fos messenger RNA expression was analyzed by Northern blotting. The modulating effects of EGCG on the activation of Raf-1, Akt, and phosphatidylinositol 3-kinase (PI 3-kinase) were examined by coimmunoprecipitation, Western blotting, and PI 3-kinase activity assay. Interactions between c-Fos and CCL2 promoter were evaluated by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay. The effect of EGCG on CIA in rats was examined clinically and immunohistochemically. RESULTS EGCG inhibited OSM-stimulated CCL2 expression in primary human osteoblasts and MG-63 cells. In MG-63 cells, EGCG alleviated the OSM-induced phosphorylation of Raf-1 at Ser338 but restored the dephosphorylation of Raf-1 at Ser259. EGCG increased the activity of PI 3-kinase, the level of phosphorylated Akt (Ser473), and binding between Raf-1 and active Akt. EMSA and ChIP assay revealed that EGCG attenuated activator protein 1 (AP-1)-CCL2 promoter interaction, possibly by reducing c-Fos synthesis. Codistribution of CD68+ macrophages and CCL2+ osteoblasts in osteolytic areas was obvious in the CIA model. Administration of EGCG markedly diminished the severity of CIA, macrophage infiltration, and the amount of CCL2-synthesizing osteoblasts. CONCLUSION By stimulating PI 3-kinase activity, EGCG promoted Akt/Raf-1 crosstalk, resulting in decreased AP-1 binding to CCL2 promoter, and finally reduced CCL2 production in osteoblasts. EGCG alleviated the severity of CIA, probably by suppressing CCL2 synthesis in osteoblasts to diminish macrophage infiltration. Our data support the therapeutic potential of EGCG on arthritis.

Evaluation of the root and root canal systems of mandibular first premolars in northern Taiwanese patients using cone-beam computed tomography

BACKGROUND/PURPOSE Cone-beam computed tomography (CBCT) can provide valuable data for root canal systems of human teeth in vivo. This study used CBCT to evaluate the number of roots and canals of 300 mandibular first premolars in 150 northern Taiwanese patients. METHODS The root canal systems of 300 mandibular first premolars in 150 northern Taiwanese patients with bilateral premolars were analyzed by CBCT. RESULTS Of the 300 mandibular first premolars, 197 (65.7%) had one root with one canal (1R1C), 49 (16.3%) had one root with two canals (1R2C), 51 (17.0%) had two roots with one canal in each root (2R2C), and three (1.0%) had three roots with one canal in each root (3R3C). Statistical analyses showed that women had a significantly higher incidence of 1R1C mandibular first premolars (71.4%) than men (58.8%, p = 0.031), and men had a significantly higher incidence of 2R2C mandibular first premolars (27.2%) than women (8.5%, p < 0.001). One hundred and twenty-two (81.3%) of the 150 patients had a symmetrical root and root canal system between the right and left mandibular first premolars. Men had a significantly higher symmetrical rate of 2R2C mandibular first premolars (26.5%) than women (8.2%, p = 0.013). CONCLUSION Approximately 82% of mandibular first premolars in northern Taiwanese patients have one root with either one or two canals. There are significant differences in the number of roots and canals and symmetry of the root canal system of bilateral mandibular first premolars between male and female northern Taiwanese patients.

A method for measuring three-dimensional mandibular kinematics in vivo using single-plane fluoroscopy

OBJECTIVES Accurate measurement of the three-dimensional (3D) motion of the mandible in vivo is essential for relevant clinical applications. Existing techniques are either of limited accuracy or require the use of transoral devices that interfere with jaw movements. This study aimed to develop further an existing method for measuring 3D, in vivo mandibular kinematics using single-plane fluoroscopy; to determine the accuracy of the method; and to demonstrate its clinical applicability via measurements on a healthy subject during opening/closing and chewing movements. METHODS The proposed method was based on the registration of single-plane fluoroscopy images and 3D low-radiation cone beam CT data. It was validated using roentgen single-plane photogrammetric analysis at static positions and during opening/closing and chewing movements. RESULTS The method was found to have measurement errors of 0.1 ± 0.9 mm for all translations and 0.2° ± 0.6° for all rotations in static conditions, and of 1.0 ± 1.4 mm for all translations and 0.2° ± 0.7° for all rotations in dynamic conditions. CONCLUSIONS The proposed method is considered an accurate method for quantifying the 3D mandibular motion in vivo. Without relying on transoral devices, the method has advantages over existing methods, especially in the assessment of patients with missing or unstable teeth, making it useful for the research and clinical assessment of the temporomandibular joint and chewing function.

Static craniofacial measurements and dynamic airway collapse patterns associated with severe obstructive sleep apnoea: a sleep MRI study.

Using sleep MRI, we aimed to identify static craniofacial measurements and dynamic upper airway collapse patterns associated with severe obstructive sleep apnoea (OSA) during natural sleep in age and BMI‐matched patients.

Measurement of Mandibular Growth Using Cone-Beam Computed Tomography: A Miniature Pig Model Study

The purpose of this study was to measure the long-term growth of the mandible in miniature pigs using 3D Cone-Beam Computerized Tomography (CBCT). The mandibles of the pigs were scanned monthly over 12 months using CBCT and the 3D mandibular models were reconstructed from the data. Seventeen anatomical landmarks were identified and classified into four groups of line segments, namely anteroposterior, superoinferior, mediolateral and anteroinferior. The inter-marker distances, inter-segmental angles, volume, monthly distance changes and percentage of changes were calculated to describe mandibular growth. The total changes of inter-marker distances were normalized to the initial values. All inter-marker distances increased over time, with the greatest mean normalized total changes in the superoinferior and anteroposterior groups (p<0.05). Monthly distance changes were greatest during the first four months and then reduced over time. Percentages of inter-marker distance changes were similar among the groups, reaching half of the overall growth around the 4th month. The mandibular volume growth increased non-linearly with time, accelerating during the first five months and slowing during the remaining months. The growth of the mandible was found to be anisotropic and non-homogeneous within the bone and non-linear over time, with faster growth in the ramus than in the body. These growth patterns appeared to be related to the development of the dentition, providing necessary space for the teeth to grow upward for occlusion and for the posterior teeth to erupt.

Acoustic-integrated dynamic MR imaging for a patient with obstructive sleep apnea

Obstructive sleep apnea syndrome (OSAS) is caused by multi-level upper airway obstruction. Anatomic changes at the sites of obstruction may modify the physical or acoustic properties of snores. The surgical success of OSA depends upon precise localization of obstructed levels. We present a case of OSAS who received simultaneous dynamic MRI and snore acoustic recordings. The synchronized image and acoustic information successfully characterize the sites of temporal obstruction during sleep-disordered breathing events.

Synchronized imaging and acoustic analysis of the upper airway in patients with sleep-disordered breathing.

Progressive narrowing of the upper airway increases airflow resistance and can produce snoring sounds and apnea/hypopnea events associated with sleep-disordered breathing due to airway collapse. Recent studies have shown that acoustic properties during snoring can be altered with anatomic changes at the site of obstruction. To evaluate the instantaneous association between acoustic features of snoring and the anatomic sites of obstruction, a novel method was developed and applied in nine patients to extract the snoring sounds during sleep while performing dynamic magnetic resonance imaging (MRI). The degree of airway narrowing during the snoring events was then quantified by the collapse index (ratio of airway diameter preceding and during the events) and correlated with the synchronized acoustic features. A total of 201 snoring events (102 pure retropalatal and 99 combined retropalatal and retroglossal events) were recorded, and the collapse index as well as the soft tissue vibration time were significantly different between pure retropalatal (collapse index, 2 ± 11%; vibration time, 0.2 ± 0.3 s) and combined (retropalatal and retroglossal) snores (collapse index, 13 ± 7% [P ≤ 0.0001]; vibration time, 1.2 ± 0.7 s [P ≤ 0.0001]). The synchronized dynamic MRI and acoustic recordings successfully characterized the sites of obstruction and established the dynamic relationship between the anatomic site of obstruction and snoring acoustics.

Correction: Measurement of Mandibular Growth Using Cone-Beam Computed Tomography: A Miniature Pig Model Study.

There is an error in affiliation 4 for author Chih-Chung Hu. Affiliation 4 should be: Department of Mechanical Engineering, Ming Chi University of Technology, New Taipei City, Taiwan, R.O.C.

A dental implant-based registration method for measuring mandibular kinematics using cone beam computed tomography-based fluoroscopy.

PURPOSE This study aimed to develop and evaluate experimentally an implant-based registration method for measuring three-dimensional (3D) kinematics of the mandible and dental implants in the mandible based on dental cone beam computed tomography (CBCT), modified to include fluoroscopic function. MATERIALS AND METHODS The proposed implant-based registration method was based on the registration of CBCT data of implants/bones with single-plane fluoroscopy images. Seven registration conditions that included one to three implants were evaluated experimentally for their performance in a cadaveric porcine headmodel. RESULTS The implant-based registration method was shown to have measurement errors (SD) of less than -0.2 (0.3) mm, 1.1 (2.2) mm, and 0.7 degrees (1.3 degrees) for the in-plane translation, out-of-plane translation, and all angular components, respectively, regardless of the number of implants used. The corresponding errors were reduced to less than -0.1 (0.1) mm, -0.3 (1.7) mm, and 0.5 degree (0.4 degree) when three implants were used. CONCLUSION An implant-based registration method was developed to measure the 3D kinematics of the mandible/implants. With its high accuracy and reliability, the new method will be useful for measuring the 3D motion of the bones/implants for relevant applications.

Upper Airway Dimensions in Snoring: Acoustical and MRI Findings

Objective: OSA is caused by soft tissue collapse of the upper airway; treatment strategies can be determined depending on accurately localizing the obstruction sites. Acoustic analysis of snoring might provide a valuable way to localize the obstruction, if the association between the acoustics and the dynamics of the upper airway during OSA can be identified. Method: Nine PSG OSA patients were enrolled. Dynamics of upper airway and the acoustic manifestations of snore events during natural sleep were recorded with dynamic MRI and a fiber-optic microphone simultaneously. The Gabor/wavelet transformation was applied to extract the acoustic representation of OSA events by removing the repeated-appearing MRI scanning background noises. Results: All of the 9 patients were men (mean age, 48.3 ± 9.9 years, mean BMI, 25.1 ± 1.9). The snore events were categorized into typical (velopharyngeal) and mixed (combined with hypopharyngeal) obstructions. The mean frequency (161 ± 17.4 vs 188 ± 24.1 Hz; P < 10-16) and high (151~350 Hz)/low(80~150 Hz) frequency power ratio (1.08 ± 0.31 vs 1.55 ± 0.42 Hz; P < 10-16) of the snore sounds were significantly higher in mixed obstructions. However, the dynamic patterns of the frequency modulation varied with structural changes identified by dMRI. During the snore events, different characteristics of shifts in frequency were found (mean frequency changes: −28.3 ± 21.4 in typical obstruction vs 12.5 ± 22.9 Hz for mixed obstruction; P < 10-32), which gives better discrimination power. Conclusion: The dynamics of acoustic patterns derived by Gabor spectrogram are unique and characteristics in different types of obstruction with the advantage of low cost and easy availability. Therefore, the dynamics of acoustic patterns warrants further investigation in combination with instantaneous structural changes of the obstruction sites in OSA patients through dMRI.