Optimal timing and frequency of bone marrow soup therapy for functional restoration of salivary glands injured by single-dose or fractionated irradiation.

Injections of bone marrow (BM) cell extract, known as 'BM soup', were previously reported to mitigate ionizing radiation (IR) injury to salivary glands (SGs). However, the optimal starting time and frequency to maintain BM soup therapeutic efficacy remains unknown. This study tested the optimal starting time and frequency of BM soup injections in mice radiated with either a single dose or a fractionated dose. First, BM soup treatment was started at 1, 3 or 7 weeks post-IR; positive (non-IR) and negative (IR) control mice received injections of saline (vehicle control). Second, BM soup-treated mice received injections at different frequencies (1, 2, 3 and 5 weekly injections). Third, a 'fractionated-dose radiation' model to injure mouse SGs was developed (5 Gy × 5 days) and compared with the single high dose radiation model. All mice (n = 65) were followed for 16 weeks post-IR. The results showed that starting injections of BM soup between 1 and 3 weeks mitigated the effect of IR-induced injury to SGs and improved the restoration of salivary function. Although the therapeutic effect of BM soup lessens after 8 weeks, it can be sustained by increasing the frequency of weekly injections. Moreover, both single-dose and fractionated-dose radiation models are efficient and comparable in inducing SG injury and BM soup treatments are effective in restoring salivary function in both radiation models. In conclusion, starting injections of BM soup within 3 weeks post-radiation, with 5 weekly injections, maintains 90-100% of saliva flow in radiated mice.

[Research of the synergetic action of fluid shear stress and 17-beta estradiol on the proliferation of MC3T3-E1 cells].

OBJECTIVE: To explore the suitable level and action time of 17-beta estradiol and fluid shear stress (FSS) and their combined effect on the proliferation of rat osteoblasts in vitro. METHODS: MC3T3-E1 osteoblasts were adopted after subcultured and different concentrations of 17-beta estradiol and FSS values were applied respectively on MC3T3-E1, the suitable level of 17-beta estradiol and FSS were selected through MTT and alkaline phosphatase (ALP). Then the two factors at the suitable level were applied simultaneously to MC3T3-E1 to detect the proliferation activity. RESULTS: Seventeen-beta estradiol(10(-8) mol x L(-1) for 5 d and 12 x 10(-5) N FSS for 60 min exhibited better effects on the proliferation activity than the other groups respectively, and the combined effect of both factors was better than any single-factor treated group. CONCLUSION: Both 17-beta estradiol and FSS have a suitable threshold in promoting proliferation of osteoblasts, and two-factor treated group exhibits better effect than any other single-factor treated groups. Therefore 17-beta estradiol and FSS have a synergetic action on differentiation and proliferation of osteoblasts.

[The intercellular communication condition of alveolar bone with traumatic occlusion at early stage in rats].

OBJECTIVE: To study the intercellular communication of alveolar bone during traumatic occlusion at early stage in rats. METHODS: The occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 hours, the alveolar bone tissues of the lower jaws first molars at the both sides were taken out under anesthesia The various 27 000 genes were identified with genome-wide microarray, and further were investigated with reverse transcription-polymerase chain reaction (RT-PCR) and Pathway analysis. RESULTS: Total 586 gene were found to be changed, 106 different signal pathways got involved with Pathway analysis, including cell adhesion molecules(CAMS), adhesions junction, gap junction, focal adhesion and tight junction, and the cytokines associated with bone metabolism in above 5 signal pathways were all down-regulated. CONCLUSION: At the early phase of the occlusal trauma, intercellular communication in rat's alveolar bone were inhibited.

[The primary study on the gene expression profiles of alveolar bone with traumatic occlusion in early stage in rats].

OBJECTIVE: To study the gene expression profiles of traumatic occlusion in early stage with the animal model of rats. METHODS: The occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 hours, the alveolar bone tissue of the first molars at the both sides of rats' lower jaws were taken out under anesthesia. The different expressive genes were shown by genome-wide microarray, which comprises about 27 000 genes and analyzed the different expressive genes with Pathway and GO analysis, finally the results of the microarray were examined by real time-polymerase chain reaction (RT-PCR). RESULTS: In the results of the study, 586 different expressions were found, of which the expressions of 166 genes increased and 420 genes decreased. 106 different pathways were involved with Pathway analysis and 270 different functional classification related to GO analysis. CONCLUSION: The balance of the lower alveolar bone is destroyed after 24 hours of traumatic occlusion. At early phase of the occlusal trauma, osteogenesis and bone formation in alveolar bone are inhibited, yet osteoblast genesis and bone resorption are not significant.

[The inspiration of comprehensive quality related cutting-edge curriculum of the University of California, Los Angeles School of Dentistry].

In this article, the author introduced three course of comprehensive quality training set up in the University of California, Los Angeles School of Dentistry (UCLA), named "introduction to behavioral science", "patient management", "methods in evidence-based dentistry". In order to provide reference for our medical reform of dental students, the content of the three courses were provided and the importance of comprehensive quality training was evaluated. The curriculum type, number of hours and time to deliver were compared between UCLA and School of Stomatology, Shandong University. It was found that the comprehensive quality training-related curriculum, offered in Shandong University covered fewer content, fewer number of hours and delivered later. Therefore, the author suggests the domestic dental institutions set up the three cutting-edge courses integrated with clinical practice as well. Supported by Teaching Reform Project of Shandong University (2009174).

[Analysis of the curriculum of the University of California, Los Angeles School of Dentistry].

By comparative analysis of the curriculum of the University of California, Los Angeles (UCLA) School of Dentistry with Shandong University College of Stomatology, this paper explored what could be used as reference for Chinese dental educators. The curriculum characteristics and teaching ways in UCLA was analyzed; the dental courses of UCLA were compared with Shandong University, fourteen courses opened in UCLA were not opened in Shandong University; eight forefront courses selected from the fourteen courses were introduced. The analysis showed that in certain degree the curriculum characteristics and teaching ways of UCLA could be used for reference and fourteen forefront courses were also necessary. It's suggested to increase the proportion of dental courses, increase hours for experiments, combine theories and experiments tightly and gradually open forefront courses such as Clinical Applications of Dental Morphology, Esthetic Dentistry, Geriatric Dentistry, Hospital Dentistry, Health Policy Issues, Methods in Evidence-based Dentistry, Introduction to Behavioral Science, Patient Management and so on within domestic universities.