转录调控因子CBF1（RBP—Jκ）对Cbfal和Ose2元件启动子活性的影响

目的：探讨Notch信号转录调控因子CBF1(RBP—Jκ)对核心结合因子Cbfal基因启动子和骨钙素基因启动子区域Ose2元件启动子活性的影响。方法：构建CBF1真核表达载体pCMV—Tag4／CBF1；将梯度浓度pCMV—Tag4／CBF1和荧光素酶报告质粒共转染两成骨前体细胞系Kusa—A1和Kusa-O，用双荧光素酶报告基因方法检测Cbfa1和Ose2元件启动子活性。结果：随CBF1浓度增加，Kusa—A1和Kusa-O细胞中Cbfa1和Ose2元件启动子活性均逐渐提高。统计分析表明：Kusa—A1细胞中1／40μg／μL实验组两启动子活性均与对照组差异显著；Kusa-0细胞中1／40μg／μL实验组Ose2元件启动子活性与对照组差异显著。结论：转录调控因子CBF1可以促进Cbfa1和Ose2元件启动子活性，从而可能对细胞的成骨性分化有正调节作用。     

骨形态发生蛋白信号通路的负向调节

骨形态发生蛋白(BMP)是多功能的生长因子,具有调节细胞的增殖和分化以及促进骨、软骨和牙组织生成的作用。下面通过细胞外对抗物、细胞内BMP抑制因子和负调节转录因子等内容就BMP信号通路的负向调节研究进展作一综述。     

Analysis of brain activity during clenching by fMRI

It has been considered difficult to obtain satisfactory functional magnetic resonance images (fMRI) during jaw movements because the head motion during jaw movements makes artefacts on the images. To avoid these artefacts, we chose clenching task and larger pixels to allow some head motion of the subjects. Further the study discarded all data from subjects whom the head was evaluated to move more than 0.3 mm. The study examined 10 healthy right-handed volunteers with echo-planar magnetic resonance (MR) imaging and functional MR signal intensity changes could be obtained in all subjects. However, in the analysis of each pixel of individuals, three different types of pixels were established. It was determined that the pixels that synchronized positively with the task on/off and where signal intensity increase was below 10% expressed the real brain activity. Pixels showing the real brain activity were found in the sensory, motor and pre-motor cortexes in both hemispheres in all subjects, and also in the insula region of two subjects. No pixels were found in the striatum and supplementary motor areas. From the above careful consideration and individual analysis of each pixel, it was concluded that brain activity during the clenching task could be obtained by fMRI.     

The dynamic range of TMJ sounds

It is of clinical interest to record the amplitudes of temporomandibular joint (TMJ) sounds. The aim was to test the hypothesis that sealing the meatus, when placing a microphone in the ear canal affects such recording by increasing the sound pressure level (SPL). Bilateral recordings of 249 TMJ clickings were made from three subjects, using sampling rates of 48 or 96 kHz and 24 bits A/D conversion, with and without the ear canals sealed by Silicone putty. The peak-to-peak equivalent sound pressure level (peSPL) was higher (P < 0.001) when the ear canal was sealed (range of mean differences was 8.3-24.9 dB peSPL). This means that the signal to noise ratio can be improved by sealing the meatus because the electronic noise level is not increased. Most important is that the dynamic range of the clicking sounds was 62 dB that is larger than the effective dynamic range of a 16 bits sound card. Future studies are needed to establish normative peSPL values. However, cards with at least 24 bits A/D conversion will be required, especially in patients with suspected disc displacement with reduction, where the difference in loudness between opening and closing clicking often is large.     

Examination of the signal transduction pathways leading to upregulation of tissue type plasminogen activator by Porphyromonas endodontalis in human pulp cells

AIM: To investigate the tissue type plasminogen activator (t-PA) activity in human pulp cells stimulated with Porphyromonas endodontalis (P. endodontalis) in the absence or presence of p38 inhibitor SB203580, mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphatidylinositaol 3-kinase (PI3K) inhibitor LY294002. METHODOLOGY: The supernatants of P. endodontalis were used to evaluate t-PA activity in human pulp cells using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search for possible signal transduction pathways, SB203580, U0126 and LY294002 were added to test how they modulated the t-PA activity. RESULTS: The main casein secreted by human pulp cells migrated at 70 kDa and represented t-PA. Secretion of t-PA was found to be stimulated with P. endodontalis during 2-day cultured period (P < 0.05). From the results of casein zymography and ELISA, SB203580 and U0126 significantly reduced the P. endodontalis stimulated t-PA production respectively (P < 0.05). However, LY294002 lacked the ability to change the P. endodontalis stimulated t-PA production (P > 0.05). CONCLUSIONS: Porphyromonas endodontalis enhances t-PA production in human pulp cells, and the signal transduction pathways p38 and MEK are involved in the inhibition of t-PA.     

颈部恶性肿瘤转移淋巴结与炎性淋巴结的MRI鉴别诊断

ＭＲＩ（磁共振成像）用来鉴别恶性肿瘤转移的淋巴结和炎性淋巴结，尚未有一个明确的标准。本研究对２４例颈部肿瘤转移淋巴结和１４例颈部炎性淋巴结行ＭＲＩ检查。结果表明：颈部恶性肿瘤转移淋巴结的ＭＲＩ上，Ｔ１加权为均匀略低和等信号，Ｔ２加权表现为不均匀的略高信号与高信号混合。转移淋巴结轮廓清晰，周围可出现不完全环状脂肪增生带，而炎性淋巴结在Ｔ１和Ｔ２加权上分别为：等信号和略高信号，且周边欠清晰，边缘脂肪模糊。至目前为止，ＭＲＩ可被视为鉴别上述两者的一种有效方法。     

Immunohistochemical detection of phosphorylated JNK, p38 MAPK, and ERK5 in ameloblastic tumors

BACKGROUND: To evaluate roles of mitogen-activated protein kinases (MAPKs) in oncogenesis and cytodifferentiation of odontogenic tumors, expression of phosphorylated JNK (p-JNK), p38 MAPK (p-p38 MAPK), and ERK5 (p-ERK5) was analyzed in ameloblastic tumors as well as in tooth germs. METHODS: Ten tooth germs, 47 ameloblastomas, and 5 malignant ameloblastic tumors were examined immunohistochemically with the antibodies against p-JNK, p-p38 MAPK, and p-ERK5. RESULTS: Immunoreactivity for p-JNK was detected in epithelial or neoplastic cells detached from the basement membrane in 7 tooth germs and 7 ameloblastomas, and the expression levels of p-JNK in ameloblastic tumors were significantly lower than that in tooth germs. Expression of p-p38 MAPK was found in epithelial or neoplastic cells in tooth germs and ameloblastic tumors except for two ameloblastomas, and increased expression was found in keratinizing cells of acanthomatous ameloblastomas. The expression level of p-p38 MAPK in ameloblastomas was significantly higher than the levels in tooth germs and malignant ameloblastic tumors. Immunoreactivity for p-ERK5 was found predominantly in epithelial or neoplastic cells near the basement membrane in tooth germs and ameloblastic tumors. The expression levels of p-ERK5 in ameloblastic tumors were slightly higher than that in tooth germs, and plexiform ameloblastomas showed significantly higher p-ERK5 expression than follicular ameloblastomas. CONCLUSION: Expression of p-JNK, p-p38 MAPK, and p-ERK5 in tooth germs and ameloblastic tumors suggests that these MAPK signaling pathways contribute to cell proliferation, differentiation, or apoptosis in both normal and neoplastic odontogenic tissues. Altered expression of these phosphorylated MAPKs in ameloblastic tumors may be involved in oncogenesis and tumor cell differentiation.     

Conditioned-medium of stem cells from human exfoliated deciduous teeth prevent apoptosis of neural progenitors

PurposeThis study aimed to evaluate the neuroprotective ability of the conditioned medium of stem cells from human exfoliated deciduous teeth (CM-SHED) to prevent glutamate-induced apoptosis of neural progenitors.Materials and methodsNeural progenitors were isolated from two-day-old rat brains, and the conditioned medium was obtained from a mesenchymal stem cell SHED. Four groups were examined: neural progenitor cells cultured in neurobasal medium with (N + ) and without (N-) glutamate and glycine, and neural progenitor cells cultured in CM-SHED with (K + ) and without (K-) glutamate and glycine.ResultsThe expression of GABA A1 receptor (GABAAR1) messenger RNA (mRNA) in neural progenitor measured by real-time quantitative PCR. GABA contents were measured by enzyme-linked immunosorbent assay, whereas the apoptosis markers caspase-3 and 7-aminoactinomycin D were analysed with a Muse® cell analyzer. The viability of neural progenitor cells in the K + group (78.05 %) was higher than the control group N- (73.22 %) and lower in the N + group (68.90 %) than in the control group. The K + group showed the highest GABA content, which significantly differed from that in the other groups, whereas the lowest content was observed in the N + group. The expression level of GABAAR1 mRNA in the K + group was the highest compared to that in the other groups. CM-SHED potently protected the neural progenitors from apoptosis.ConclusionsCM-SHED may effectively prevent glutamate-induced apoptosis of neural progenitors.     

机械压应力下骨硬化蛋白对成牙骨质细胞功能影响及机制的体外研究

目的 探究骨硬化蛋白（SOST）对处于机械压应力中的永生化成牙骨质细胞（OCCM-30）的功能影响及其相关的机制。方法 用不同浓度SOST培养液（0、25、50、100 ng·mL ^-1）处理细胞后依靠四点弯曲细胞力学加载器对细胞加载大小为2 000 μstrain、频率是0.5 Hz的单轴压应力6 h,用免疫印迹法检测β-连环蛋白（β-catenin）、磷酸化的细胞信号转导分子p-smad1/5/8、细胞信号转导分子smad1/5/8的蛋白水平;用碱性磷酸酶（ALP）活性检测法检测ALP活性;用荧光实时定量PCR检测核心结合蛋白因子2（Runx-2）、骨钙素（OCN）、骨涎蛋白（BSP）以及细胞核因子κB受体活化因子（RANKL）、骨保护因子（OPG）的表达。结果 p-smad1/5/8随着SOST浓度增加,呈减低的趋势,而β-catenin、smad1/5/8未有显著差异性。在仅对细胞加力时ALP活性降低,随SOST浓度升高,ALP活性逐渐发生下降,Runx-2、OCN和BSP的表达也都呈现降低趋势,RANKL的表达随着SOST增加而升高,OPG则随之下降。结论 压应力下,SOST的升高会对骨形态发生蛋白（BMP）/smad 通路产生抑制作用,对β-catenin表达未产生明显改变。外源性SOST对于BMP存在反馈性的负向调节作用。压应力下SOST对OCCM-30的矿化功能是抑制的,其机制或许是一方面利用BMP信号通路对成骨相关因子Runx2、OCN、BSP等实现下调,另一方面提高了与破牙骨质有关分子 RANKL/OPG的比率。