Vestibular evoked myogenic potentials are heavily dependent on type I hair cell activity of the saccular macula in guinea pigs

This study applied the vestibular evoked myogenic potential (VEMP) test to guinea pigs coupled with electronic microscopic examination to determine whether VEMPs are dependent on type I or II hair cell activity of the saccular macula. An amount of 0.05 ml of gentamicin (40 mg/ml) was injected directly overlaying, but not through, the round window membrane of the left ear in guinea pigs.One week after surgery, auditory brainstem response test revealed normal responses in 12 animals (80%), and elevated thresholds in 3 animals (20%). The VEMP test using click stimulation showed absent responses in all 15 animals (100%). Another 6 gentamicin-treated animals underwent the VEMP test using galvanic stimulation and all 6 also displayed absent responses. Ultrathin sections of the saccular macula in the gentamicin-treated ears displayed morphologic alterations in type I or II hair cells, including shrinkage and/or vacuolization in the cytoplasm, increased electron density of the cytoplasm and nuclear chromatin, and cellular lucency. However, extrusion degeneration was rare and only present in type II hair cells. Quantitative analysis demonstrated that the histological density of intact type I hair cells was 1.1 +/- 1.2/4000 microm(2) in the gentamicin-treated ears, showing significantly less than that in control ears (4.5 +/- 1.8/4000 microm(2)). However, no significant difference was observed in the densities of intact type II hair cells and supporting cells between treated and control ears. Furthermore, the calyx terminals surrounding the damaged type I hair cells were swollen and disrupted, while the button afferents contacting the damaged type II hair cells were not obviously deformed. Based on the above results, we therefore conclude that VEMPs are heavily dependent on type I hair cell activity of the saccular macula in guinea pigs.     

Association of HPV infections with second primary tumors in early-staged oral cavity cancer

Oral Diseases (2012) 18 , 809–815 Objective: The infection of human papilloma virus (HPV) has been reported in head and neck cancer; however, the clinical significance of HPV infection on the pathogenesis of oral cavity squamous cell carcinoma (OSCC) is still uncertain. Materials and Methods: The study recruited 103 patients with pathological early‐stage OSCC between March 1997 and December 2003 from Chang Gung Memorial Hospital, Taiwan. Tumor specimens were HPV‐genotyped by the EasychipVR HPV Blot method. Clinical association study was performed by using chi‐square, Kaplan–Meier, and logrank tests. Results: Thirty‐one patients (30.1%) were positive for HPV infection. The most frequent HPV types were types 16 (16 patients, 51.6%) and 18 (seven patients, 22.6%). HPV infection was not associated with tumor aggressiveness (pathological tumor stage or differentiation status), risk exposure (alcohol, cigarette, or areca quid chewing habit), or the treatment outcome (disease‐free survival or overall survival). However, infection with HPV‐18 was associated with the occurrence of a second primary cancers (P = 0.033), indicating the infection of HPV in OSCC enhances the susceptibility of developing secondary malignancy. Conclusions: There are 30% of the patients with OSCC infected with HPV, with most high‐risk types. HPV‐18 infection may enhance the susceptibility of second primary tumors. Large scale of validation study will be needed to confirm this result.     

Detection accuracy of proximal caries by phosphor plate and cone-beam computerized tomography images scanned with different resolutions

This study was carried out to assess whether the spatial resolution has an impact on the detection accuracy of proximal caries in flat panel CBCT (cone beam computerized tomography) images and if the detection accuracy can be improved by flat panel CBCT images scanned with high spatial resolution when compared to digital intraoral images. The CBCT test images of 45 non-restored human permanent teeth were respectively scanned with the ProMax 3D and the DCT Pro scanners at different resolutions. Digital images were obtained with a phosphor plate imaging system Digora Optime. Eight observers evaluated all the test images for carious lesion within the 90 proximal surfaces. With the histological examination serving as the reference standard, observer performances were evaluated by receiver operating characteristic (ROC) curves. The areas under the ROC curves were analyzed with two-way analysis of variance. No significant differences were found among the CBCT images and between CBCT and digital images when only proximal enamel caries was detected (p = 0.989). With respect to the detection of proximal dentinal caries, significant difference was found between CBCT and digital images (p < 0.001) but not among CBCT images. The spatial resolution did not have an impact on the detection accuracy of proximal caries in flat panel CBCT images. The flat panel CBCT images scanned with high spatial resolution did not improve the detection accuracy of proximal enamel caries compared to digital intraoral images. CBCT images scanned with high spatial resolutions could not be used for proximal caries detection.     

Enhanced bone regeneration around dental implant with bone morphogenetic protein 2 gene and vascular endothelial growth factor protein delivery

Objective: To evaluate the synergistic effect of bone morphogenetic protein 2 (BMP‐2) and vascular endothelial growth factor (VEGF) on the repair of bone defects around dental implants. Material and methods: Five groups of scaffold were fabricated by a freeze‐drying method, including pure chitosan/collagen scaffold; scaffold loaded with adenoviruses expressing BMP‐2, adenoviruses expressing VEGF, both adenoviruses expressing BMP‐2 and VEGF, VEGF protein and adenovirus expressing BMP‐2. In vitro studies examined whether bone marrow stromal cells were responsive to these scaffolds over time. Bone formation capacity, bone‐to‐implant contact, as well as removal torque values were investigated in vivo. Differences between the various groups were statistically analyzed using the one‐way analysis of variance test. Results: The in vitro study revealed a burst and rapid release of VEGF with a sustained high‐level expression of BMP‐2 in scaffold combined with VEGF protein and adenoviruses expressing BMP‐2. Histomorphometry demonstrated that scaffolds expressing BMP‐2 enhanced more bone formation compared with other groups; VEGF alone is insufficient to promote bone formation. New bone formation in the bone defects around dental implants, bone‐to‐implant contact and mean peak removal torque showed statistically significant difference for the adenoviral vector encoding human bone morphogenetic protein 2 (Ad‐BMP‐2) and VEGF protein and adenovirus expressing BMP‐2 groups. Furthermore, scaffold combined with VEGF protein and Ad‐BMP‐2 represented the best outcomes in this model. Conclusions: A combination of BMP‐2 gene and VEGF protein could have a synergistic effect in promoting bone healing. To cite this article:
Luo T, Zhang W, Shi B, Cheng X, Zhang Y. Enhanced bone regeneration around dental implant with bone morphogenetic protein 2 gene and vascular endothelial growth factor protein delivery.
Clin. Oral Impl. Res. 23 , 2012 467–474.
doi: 10.1111/j.1600‐0501.2011.02164.x     

第四军医大学口腔医学博物馆在教学中的应用

第四军医大学口腔医院口腔医学博物馆成立于2010年,面积539 m2,馆内共有13个展区,收藏和展出头颅、牙颌系统化石、口腔器械、教具、书籍等实物4 500余套件。博物馆为口腔医学发展史的研究提供了丰富的资料,为口腔医学的传承、教育和发展起到了积极的推动作用。     

The effects of gradually induced backward movement of the mandible by a Twin Inclined Plane Device in rats

Abstract Objective: To develop a model of gradually induced backward movement of the mandible under normal masticatory action and to examine morphological changes in the mandible and condylar cartilage in rats. Materials and Methods: The newly developed Twin Inclined Plane Device (TIPD) was composed of upper and lower posterior metal crowns with a long inclined plane on both sides separately and was applied in experimental groups of 6-week-old male Wister rats. After 3, 14, 30, and 60?days, the rats were euthanatized and samples were collected. Various measurements and hematoxylin-and-eosin stains were performed. Results: From day 30 on, the length of the condylar process was shorter in the TIPD groups than in the control groups (P < .05). The angulation of the condylar process axis to the mandibular plane was greater in the TIPD groups (P < .01). The thickness of the condylar cartilage in the posterior part of the posterior region was thinner in the TIPD groups (P < .05) on day 30 and even thinner (P < .01) on day 60; from day 30 on, the thickness in the anterior part of the posterior region was thicker in the TIPD groups (P < .01). Conclusion: TIPD can successfully induce backward movement of the mandible under normal masticatory action. TIPD can cause region-specific changes in condylar cartilage and leads to a continuous remodeling.     

显脉香茶菜化学成分的研究

在继续对显脉香茶菜Ｒａｂｄｏｓｉａ ｎｅｒｖｏｓａ （Ｈｅｍｓｌ）Ｃ．Ｙ．Ｗｕ ｅｔ Ｈ．Ｗ．Ｌｉ茎叶有效成分的研究中,又分得一种新的对映－甲壳杉烷型二萜,经理化常数和波谱分析,确定其结构为１α、１５β－二羟基－６β－乙氧基－６,７－Ｂ－断裂－对映－贝壳杉－１６－烯－６,２０－环氧－７,２０－内酯,命名为显脉香茶菜丙素（ｒａｂｄｏｎｅｒｖｏｓｉｎＣ）。     

附子化学成分研究

目的: 研究附子Aconitum carmichaelii Debx. 的子根的化学成分。方法: 采用硅胶、MCI 以及 Sephadex LH-20 柱色谱等分离,运用波谱数据鉴定化合物的结构。结果: 从附子中分离得到12个化合物,分别鉴定为烟酰胺(1)、尿嘧啶(2)、次黄嘌呤(3)、腺苷(4)、尿苷(5)、5-羟甲基-吡咯-2-甲醛(6)、马齿苋酰胺E(7)、顺-对香豆酸-4-O-β-D-葡萄糖苷(8)、顺-阿魏酸-4-β-葡萄糖苷(9)、反-阿魏酸-4-β-葡萄糖苷(10)、异麦芽酚-葡萄糖苷(11)、2,4,6-三苯基-1-己烯(12)。结论: 除化合物 2 以外,其他化合物均为首次从该属植物中分离得到。