Effects and molecular mechanism of nicotine on odontoblasts / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the effects of nicotine on the proliferation of odontoblasts and explore the possible mechanism.</p><p><b>METHODS</b>Odontoblasts MDPC-23 were cultured, inoculated and divided into two groups randomly. With no stimuli added for the control group, the experimental group was stimulated by 100 microg/mL nicotine. After 8 hours, 10 micromol/L BrdU was added to label cells at S stage in cell cycle. 24 hours later, odontoblasts were fixed and immunofluorescence staining was performed with specific mouse BrdU antibody. After counterstaining with propidium iodide, BrdU positive cells were arbitrarily scored microscopically by an independent estimation conducted three times, and the corresponding total cell number in the same vision were counted in both groups. BrdU positive cell rates were calculated and compared statistically. At the same time, odontoblasts MDPC-23 were cultured and stimulated by 100 microg/mL nicotine, the dynamic Ca2+ concentration inside the cytoplasm were detected immediately by a confocal laser scanning microscope.</p><p><b>RESULTS</b>The ratio of S stage cells in the experimental group was 36.3% significantly lower than that (48.2%) in the control group. After the addition of 100 microg/mL nicotine, the Ca2+ concentration inside the cytoplasm rose rapidly, sustained at a high level for a short time and then relapsed gradually.</p><p><b>CONCLUSION</b>Nicotine had inhibitory effects on the proliferation of odontoblasts MDPC-23, which might be related to the increased Ca2+ concentration in the cytoplasm.</p>

Expression, subcellular localization and nuclear translocation of transcription factor up stream stimulatory factor-1 in odontoblasts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To examine the expression and subcellular localization of transcription factor USF1 in odontoblasts and investigate whether nuclear translocation occurs under stimuli.</p><p><b>METHODS</b>Odontoblasts MDPC-23 were cultured on coverslips and divided into 2 groups. Group 1 received no stimuli, and group 2 was stimulated by nicotine with various concentrations respectively for 1h. Then the mountings of odontoblasts were prepared and immunocytochemical staining was performed with specific USF1 antibody via SABC method. Hela cells were used as positive control.</p><p><b>RESULTS</b>The staining was positive in the cytoplasm of odontoblasts in group 1, but in the nuclei of Hela cells and in 100 mg/L nicotine-stimulated odontoblasts in group 2.</p><p><b>CONCLUSIONS</b>There exists USF1 protein in odontoblasts, which locates in the cytoplasm and could translocate into nuclei under the stimulation of nicotine.</p>

Regulation of osteopontin expression in odontoblasts by upstream stimulatory factor 1 / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the regulation effects of upstream stimulatory factor 1 (USF1) on osteopontin expression in odontoblasts.</p><p><b>METHODS</b>Odontoblast MDPC-23 was cultured and stably transfected with PCMV-USF1 or A-USF plasmids. Total RNA was extracted and osteopontin expression examined by semi-quantitative RT-PCR. Gray value of osteopontin was measured and statistic analysis performed.</p><p><b>RESULTS</b>Clones of stable PCMV-USF1 and A-USF plasmids transfection were obtained. Compared with the control, osteopontin was upregulated in PCMV-USF1 transfection group, and downregulated in A-USF transfection group.</p><p><b>CONCLUSIONS</b>Upstream stimulatory factor 1 could regulate the osteopontin expression in odontoblasts, which could be blocked partly by A-USF.</p>

Neural engineering and neural prostheses / 中国医疗器械杂志

The motivation of the brain-computer interface (BCI) research and its potential applications are introduced in this paper. Some of the problems in BCI-based medical device developments are also discussed.

Application of digital signal processing to the analysis of biomolecular sequences / 中国医疗器械杂志

A preliminary introduction is given to the application of digital signal processing to the analysis of biomolecular sequences. How to transform a character string into a numerical sequence is discussed from the time domain and the frequency domain.