Stimulation of bone formation in the expanding premaxillary suture with a GSK-3β inhibitor

OBJECTIVES

Glycogen synthase kinase-3β (GSK-3β)/β-catenin signaling mediates osteogenesis in response to mechanical loading. We tested the hypothesis that local administration of a GSK-3β inhibitor could stimulate new bone formation in the expanding premaxillary suture.

MATERIALS AND METHODS

Thirty-five Sprague-Dawley rats were subjected to premaxillary suture expansion using a helix spring. The experimental rats were given one or two local injections of SB-415286, a small-molecule GSK-3β inhibitor. Animals were administered calcein and sacrificed on day 7 to quantify new bone formation. To evaluate the proliferation and differentiation of osteoblasts, rats were labeled with bromodeoxyuridine on day 1 and sacrificed on day 2 or 4. β-catenin expression was evaluated by immunohistochemical staining.

RESULTS

Two injections of SB-415286 led to an elevation of β-catenin expression and an increase in the number of proliferating osteoblasts in expanding sutures on day 2 and day 4. Consequently, new bone formation in the suture increased significantly on day 7.

CONCLUSIONS

These results suggest that local delivery of a GSK-3β inhibitor could stimulate bone formation in the expanding premaxillary suture by eliciting β-catenin signaling. GSK-3β could be a pharmaceutical target for improving the effect of orthodontic treatments such as rapid palatal expansion.

Lithium delivery enhances bone growth during midpalatal expansion

Lithium is an activator of β-catenin signaling, and β-catenin mediates bone acquisition in response to mechanical loading in the bone. We tested the hypothesis that lithium enhances new bone formation during midpalatal suture expansion. Forty-eight Wistar rats with or without suture expansion were gavage-fed daily with lithium chloride or sodium chloride. We labeled the rats with bromodeoxyuridine to evaluate the proliferation and differentiation of the osteoprogenitors. Lithium increased β-catenin expression and cell proliferation in expanding sutures. Initial delay in the differentiation of osteoprogenitors into mature osteoblasts by lithium treatment corresponded with expansion of pre-osteoblasts, which preceded the increase of new bone formation in the suture. These results suggested that β-catenin regulates proliferation of osteoprogenitors and maturation of osteoblasts during midpalatal suture expansion osteogenesis, and that lithium enhances bone regeneration by elevating β-catenin expression. Lithium treatment could be a pharmaceutical aid to improve the stability of orthodontic treatment like rapid palatal expansion.

Treatment of municipal wastewater with the sequence batch reactor under uncoupling metabolic conditions

The activated sludge process generates large quantities of excess sludge as by-product, which is one of the most serious challenges in biological wastewater treatment. In this study, the feasibility of 2,4,6-trichlorophenol (TCP) as metabolic uncoupler to reduce sludge generation in the Sequence Batch Reactor (SBR) for the long-term treatment of municipal wastewater was evaluated. The results of 90 days continuous treatment showed that 2 mg/L TCP reduced sludge generation by about 47%, while COD removal efficiency and sludge ability to settle were only slightly decreased. The specific substrate removal rate of sludge in the reactor with TCP exceeded the removal rate of sludge in the control reactor, indicating that the catabolism and anabolism of sludge in the reactor with TCP was uncoupled. Microscopic and 16s DNA analyses showed that the microbial population of sludge varied when TCP was fed into the SBR. The occurrence of filaments and the disappearance of some protozoa in the sludge system might be reasons for the slight variation of sludge ability to settle under uncoupled metabolic conditions.

[Study on the maturation of cervical vertebra for 208 cases Shanghai adolescents growth]

OBJECTIVE:To establish a set of normal values of maturation stages of cervical vertebra for Shanghai adolescents and to provide valid reference index for assessing skeletal age while making diagnosis and treatment plan.METHODS:208 Shanghai adolescents from 11 to 15 years of age were investigated by lateral cephalometric radiographs. The growth status and the relationship of C2-C5 cervical vertebra were observed. RESULTS:The anterior and posterior vertical heights and areas of C2-C5 cervical vertebra increased progressively along with the age, the shapes of cervical vertebra bodies varied regularly. Although female goes into the young quick growing period 2 years earlier than male, the shape changes have no difference between gender. The established standard values of maturation stages of cervical vertebra for Shanghai 11-15 years old adolescents revealed that the growth and development of Shanghai adolescents are getting earlier when comparing with that of GuangDong province. CONCLUSION: The morphological variation of cervical vertebra can be used as an indicator of skeletal age to determine adolescents' growth and development status.

[The research on GH composite material of artificial bone implant in animal]

OBJECTIVE:To improve modeling different complex forms ability of pure hydroxyapatite.METHODS: Medicial gelatin and hydroxyapatite were compounded to form GH composite artifical bone.It was implanted in the tibial bone of six adult female New Zealand white rabbits.The rabbits were sacrificed at week 2, 6 and 12 respectively after operation,The bone repairing ability was assessed by histology observation.RESULTS:It connect with bone directly without inflammatory reactions with the muscle tissue.CONCLUSION:It's an ideal replacement material for bone.

[Experimental study on effect of shenyi xieli mixture on nature killer cell activity and lymphocyte reactivity to IL-2 in tumor mice]

OBJECTIVE

To explore therapeutic mechanism of Shengyi Xieli Mixture (SYXLM) on malignant tumor.

METHODS

Chemotherapy, radiotherapy and different doses of SYXLM were used to treat tumor mice [correction of rats].

RESULTS

SYXLM could enhance the nature killer (NK) cell activities of the tumor mice [correction of rats], and this effect was dose dependent (control group 52.70 +/- 6.01, SYXLM No. 1 group 59.01 +/- 10.00, SYXLM No. 2 group 78.33 +/- 10.90, P < 0.01). The NK cell activities of the tumor mice [correction of rats] were inhibited in the chemotherapy group alone, but they were enhanced in the group of chemotherapy combined with SYXLM (P < 0.05), the results were the same in the radiotherapy group alone and the group of radiotherapy combined with SYXLM (P < 0.05). The response of lymphocyte of the tumor mice [correction of rats] to IL-2 was enhanced significantly in SYXLM group compared with the control group. This response was enhanced insignificantly in the group in which radiotherapy combined with the SYXLM.

CONCLUSION

The SYXLM could enhance the function of immune system of the tumor mice [correction of rats] and diminish or reduce the side effect of radiotherapy, chemotherapy to the immune system of the tumor mice [correction of rats].

[Evaluation of BCG vaccination programme based on results of the Third Nationwide Tuberculosis Survey]

Evaluation of BCG vaccination programme had been carried out by means of re-analyzing the results of the Third Nationwide Random Sampling Survey for Epidemiology of Tuberculosis conducted in 1990. The BCG vaccination coverage among children under 4 years was 65.0% in 1990. It was lower than other reports in the past. The positive rate of tuberculin testing among children under 4 years who had the history of BCG vaccination was only 26.3%. City had the highest rate of 55.8%. The fact indicated the unsatisfactory quality of BCG vaccination in the country. The factors inducing such a lower positive rate should be clarified and overcome as soon as possible in the near future. The protective effect of BCG vaccination for children under 4 years was apparent but it was not in 5-9 age group. In this connexion, the investigation and study on the necessity of re-vaccination among primary school entrants should be conducted.