A single CT-guided percutaneous intraosseous injection of thermosensitive simvastatin/poloxamer 407 hydrogel enhances vertebral bone formation in ovariectomized minipigs.

UNLABELLED: The ultimate goal of osteoporosis treatment is prevention of fragile fracture. Local treatment targeting specific bone may decrease the incidence of osteoporotic fractures. We developed an injectable, thermosensitive simvastatin/poloxamer 407 hydrogel; a single CT-guided percutaneous intraosseous injection augmented vertebrae in ovariectomized minipigs. INTRODUCTION: The greatest hazard associated with osteoporosis is local fragility fractures. An adjunct, local treatment might be helpful to decrease the incidence of osteoporotic fracture. Studies have found that simvastatin stimulates bone formation, but the skeletal bioavailability of orally administered is low. Directly delivering simvastatin to the specific bone that is prone to fractures may reinforce the target bone and reduce the incidence of fragility fractures. METHODS: We developed an injectable, thermosensitive simvastatin/poloxamer 407 hydrogel, conducted scanning electron microscopy, rheological, and drug release analyses to evaluate the delivery system; injected it into the lumbar vertebrae of ovariectomized minipigs via minimally invasive CT-guided percutaneous vertebral injection. Three months later, BMD, microstructures, mineral apposition rates, and strength were determined by DXA, micro-CT, histology, and biomechanical test; expression of VEGF, BMP2, and osteocalcin were analyzed by immunohistochemistry and Western blots. RESULTS: Poloxamer 407 is an effective controlled delivery system for intraosseous-injected simvastatin. A single injection of the simvastatin/poloxamer 407 hydrogel significantly increased BMD, bone microstructure, and strength; the bone volume fraction and trabecular thickness increased nearly 150 %, bone strength almost doubled compared with controls (all P < 0.01); and induced higher expression of VEGF, BMP2, and osteocalcin. CONCLUSIONS: CT-guided percutaneous vertebral injection of a single simvastatin/poloxamer 407 thermosensitive hydrogel promotes bone formation in ovariectomized minipigs. The underlying mechanism appears to involve the higher expression of VEGF and BMP-2.

Injection of Toll-like receptor 4 siRNA into the ventrolateral periaqueductal gray attenuates withdrawal syndrome in morphine-dependent rats.

We assessed the role of the Toll-like receptor 4 (TLR4) gene in the ventrolateral periaqueductal gray (vlPAG) region of morphine-dependent rats on attenuating withdrawal syndrome, and regulating glutamic acid decarboxylase (GAD67), glutamic acid (Glu), and gamma-aminobutyric acid (GABA). After siRNA-mediated downregulation of TLR4, changes were observed in withdrawal behavior and downstream signaling molecules. Rats were injected into the vlPAG with TLR4 siRNA, followed by intraperitoneal injection of morphine for 5 consecutive days, and then naloxone, and the behavioral indices of morphine withdrawal were observed. 'Wet-dog' shakes, teeth chattering, and the total scores of withdrawal reactions were reduced. TLR4 expression and Glu levels were reduced, whereas GAD67 and GABA levels were increased. Overall, these findings indicate that modifying TLR4 gene expression in the vlPAG stimulates expression of the downstream signaling molecule, GAD67, which decreases Glu levels and increases GABA levels. This mechanism may explain the inhibition of withdrawal syndrome in morphine-dependent rats.

Low regional cerebral blood flow in burning mouth syndrome patients with depression.

OBJECTIVES: The main aims of this study were to (i) investigate the emotional disorder status of patients with burning mouth syndrome (BMS) and (ii) detect regional cerebral blood flow in BMS patients with the application of combined single-photon emission computed tomography and computed tomography (SPECT/CT). SUBJECTS AND METHODS: The degree of pain was measured using the visual analysis scale, and emotional disorder with the self-rating anxiety scale, self-rating depression scale, and Hamilton depression rating scale in 29 patients with BMS and 10 healthy controls. SPECT/CT was performed in 29 patients with BMS and 10 healthy controls, and statistical parametric mapping method was used for between-group analyses. RESULTS: The incidence rate of depression in patients with BMS was 31.0%. Compared to the control group, patients with BMS displayed significantly different depression and anxiety scales (P < 0.05). Significantly lower regional cerebral blood flow in the left parietal and left temporal lobes was recorded for BMS patients with depression (P < 0.05). CONCLUSIONS: Patients with BMS experience more depression and anxious emotion. Moreover, depression in patients with BMS may be associated with lower regional cerebral blood flow in the left temporal and left parietal lobes.

Practising case-based learning in oral medicine for dental students in China.

INTRODUCTION: Teacher-centred education dominates dental education in China. Student-centred education has recently been introduced in the School of Stomatology, Wuhan University, and the effectiveness of such methods needs to be tested. The purpose of this study is to compare the learning outcomes of case-based learning (CBL) and lecture-based education (LBE) in an oral medicine curriculum. MATERIALS AND METHODS: We chose oral leukoplakia as the learning subject for dental students. Forty fourth-year dental students participated in the study. First, they were presented to basic knowledge of oral leukoplakia and related oral mucosal diseases. Then, they were divided into a CBL group (n=20) and an LBE group (n=20) by random numbers. The groups experienced the remaining course in separate groups. All students answered a questionnaire on their satisfaction with the education and the same standardised written test to analyse their learning outcomes. RESULTS: Both CBL and LBE courses were well accepted by students according to the satisfactory scores of the questionnaire. The test scores of the CBL group (90.00±6.69) were significantly higher (P<0.01) than those of the LBE group (83.00±6.77). The percentage of high test score (test score≥85) of the CBL group (85%) was also significantly higher (P<0.01) than that of the LBE group (45%). CONCLUSIONS: In this example, CBL was found to be more effective than LBE to teach dental students. These findings suggest that CBL should be added in our future oral medicine curriculum for dental students.

Protective effects of baicalin on ligature-induced periodontitis in rats.

BACKGROUND AND OBJECTIVE: Baicalin is a flavonoid compound purified from the medicinal plant, Scutellaria baicalensis Georgi, and has been reported to possess anti-inflammatory and antioxidant activities. The purpose of this study was to test the ability of baicalin to influence the progression of experimental periodontitis in rats, as well as the expression of cyclooxygenase-2 and inducible nitric oxide synthase. MATERIAL AND METHODS: Adult male Sprague-Dawley rats were subjected to placement of a nylon thread around the bilateral lower first molars and killed after 7 d. Baicalin (50, 100 or 200 mg/kg) was supplied to the animals by oral gavage, starting 1 d before the induction of periodontitis. The ligature group consisted of rats subjected to periodontitis and receiving vehicle (0.5% carboxymethylcellulose) alone. The alveolar bone loss and the area fraction occupied by collagen fibers were assessed. The expression of cyclooxygenase-2 and inducible nitric oxide synthase protein in the gingiva were detected by immunohistochemistry and western blotting. RESULTS: Baicalin-treated groups presented with lower alveolar bone loss than that of the ligature group, reaching statistical significance at the dose of 200 mg/kg (p = 0.009). The area fraction of collagen fibers was significantly higher in the baicalin (200 mg/kg)-treated group than in the ligature group (p = 0.047). Baicalin treatment significantly down-regulated the protein expression for cyclooxygenase-2 (p = 0.000) and inducible nitric oxide synthase (p = 0.003), compared with the ligature group. CONCLUSION: Baicalin protects against tissue damage in ligature-induced periodontitis in rats, which might be mediated, in part, by its inhibitory effect on the expression of cyclooxygenase-2 and inducible nitric oxide synthase. These activities could support the continued investigation of baicalin as a potential therapeutic agent in periodontal disease.

Analysis of Phosphatidic Acid Binding and Regulation of PIPKI In Vitro and in Intact Cells.

Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a lipid second messenger that regulates a wide array of essential cellular events, such as signal transduction, vesicle trafficking, actin cytoskeleton dynamics, adhesion, and motility. To control the spatiotemporal production of PI(4,5)P2, the activity of type 1 phosphotidylinositol-4-phosphate-5-kinases (PIPKIs) is tightly regulated by small GTPases and another signaling lipid, phosphatidic acid (PA). It is of interest that PI(4,5)P2 is also a critical cofactor for the activation of the PA-generating enzyme, phospholipase D (PLD). It has been proposed that the reciprocal stimulation of PLD and PIPKI enzymes enables a rapid feedforward stimulation loop for the localized and acute generation of signaling lipids that are critical for the regulation of actin cytoskeletal reorganization and membrane trafficking. Here, we outline the methods for the expression and purification of PIPKIγ from bacteria, determination of direct PA binding, and activation of PIPKIγ using in vitro liposomes assays, and examination of actin cytoskeletal reorganization promoted by the PA-PIPKIγ signaling in intact cells using fluorescent microscopy.

Continuous production of poly-3-hydroxybutyrate by Ralstonia eutropha in a two-stage culture system.

Poly-3-hydroxybutyrate (PHB) is mainly accumulated by Ralstonia eutropha under unbalanced growth conditions, which limits its production in batch or fed-batch modes. The continuous production of PHB was investigated in a two-stage continuous culture system. The first-stage produced cell mass giving the maximal cell dry weight of 27.1 g l(-1) at 0.21 h(-1) of dilution rate. High specific cell growth rate results in the decrease of PHB synthesis under glucose-limited and nitrogen-rich conditions in the first-stage. The second-stage produced PHB giving the maximal PHB concentration of 47.6 g l(-1) at 0.14 h(-1) of dilution rate. Specific PHB synthetic rate reached highest value at low dilution rate under nitrogen-limited condition in the second-stage, and decreased with the increase of ammonium concentration in the culture. In the continuous culture system, the maximal PHB productivity could reach 1.43 g l(-1) h(-1) at a dilution rate of 0.12 h(-1), but with relatively low PHB content of 47.6%. Maximal yield of PHB on glucose could reach 0.36 g g(-1) glucose at 0.075 h(-1) of dilution rate with relatively high PHB productivity of 1.23 g l(-1) h(-1) and PHB content of 72.1%, respectively.

Nonlinear behavior of a liquid containing uniform bubbles: comparison between theory and experiments.

Bubbles oscillating at resonance frequency dramatically enhance nonlinearity of a bubbly liquid. A second-order nonlinear wave equation taking account of bubble pulsation is solved. Numerical calculations based on the equation are compared favorably with experimental results. Possible biological significance of the highly nonlinear medium is also discussed.

[Survey on children's dental fluorosis and fluoride content in urine after defluridation to improve drinking water].

The authors surveyed the dental fluorosis and fluoride content in urine of 8-12 years old children's in 1993 to 1999 for the evaluation of the efficiency to prevent endemic fluorosis after defluoridation to change drinking water source in Guangdong Province. Three villages: slight fluorosis area in Dazhai village, middle fluorosis area in Hupi village and severe fluorosis area in Anquan village in Fengshun County were surveyed. The results showed that the fluoride contents in drinking water were 1 mg/L (or less) in Anquan village, at the same time the prevalence of dental fluorosis and indexes of dental fluorosis were decreasing as changing water time. Fluoride contents in urine were normal. But in other two villages, the fluoride contents in drinking water exceeded 1 mg/L, therefore the children's prevalence rates and indexes of dental fluorosis were higher than the national standards. It is important to keep fluoride contents in drinking water under 1 mg/L for preventing endemic fluorosis by defluoridation to improve drinking water.

[Effects of nitrogen feeding on the accumulation of poly-beta-hydroxybutyrate with Alcaligenes eutrophus].

On the basis of analysis of PHB fermentation processes, the effects of ammonium sulfate feeding rate at PHB formation period on the PHB accumulation by Alcaligenes eutrophus were investigated. It was shown that the complete absence of nitrogen source at PHB formation phase would lead to the decline of PHB synthetic activity, and the obvious influences of different nitrogen feeding rate on PHB synthesis were observed. Higher PHB content, but relative lower cell dry weight, PHB concentration and PHB productivity could be obtained at slower nitrogen feeding rate. The excessive nitrogen feeding rate resulted in the drop of PHB content, which led to the decrease of PHB concentration and PHB productivity. The better results could be achieved when the ammonium sulfate feeding rate was set at around 0.5 g/h.

[Optimization of fermentation conditions for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with Alcaligenes eutrophus].

A close relationship, between the initial addition time and concentration of propionate and HV fraction, was observed in shaking culture of Alcaligenes eutrophus for the production of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate). The optimal initial addition time of propionate was determined at the onset of PHBV formation period. Although relatively high HV unit could be obtained under high propionate concentration, the growth and product synthetic activities were inhibited obviously. Different ratios of glucose to propionate were fed to stimulate the formation of HV unit and the results were compared. The optimizing feeding strategy of propionate was proposed based on the consideration of several fermentation index. The final cell dry weight, PHB concentration, PHB content and HV fraction in PHBV reached 52.1 g/L, 40.8 g/L, 78.3% and 16.2 mol%, respectively, Yield coefficient of HV unit to propionate and PHBV productivity were obtained to be 0.5 g/g and 0.74 g/(L/h), respectively.

[Progress on the biosynthesis of medium-chain-length polyhydroxyalkanoates by microorganisms].

Polyhydroxylkanoates(PHAs) are a class of polyesters produced as reserve materials by a large number of microorganisms under metabolic stress. The most fascinating feature of PHAs is its degradability, and which is supposed to take place of the traditional plastics made from petroleum in the future. PHAs are divided into two classes: short-chain-length PHAs(scl-PHAs) and medium-chain-length PHAs. mcl-PHAs is more welcome owing to its more wide crystallinity and higher extension to break than scl-PHAs, especially when some kind of new functional groups were incorporated into the side chain of the polyester. Since Psedumonas oleovorans is the most typical microorganism to produce mcl-PHAs, here the author summarized how P. oleovorans synthesize the mcl-PHAs and the production of mcl-PHAs by fermentation and give some of the idea about the future research of this field.

[Studies on fermentation conditions for the accumulation of poly-beta-hydroxybutyrate in Alcaligenes eutrophus].

The results of the cultivation of Alcaligenes eutrophus showed that nitrogen limitation or exhaustion could stimulate the substantial accumulation of PHB. But the exhaustion of nitrogen source in PHB formation period would result in the rapid drop of PHB synthetic rate. Oxygen limitation could also stimulate the formation of PHB, but the content of PHB in the cell was much less than that in case of nitrogen controlled conditions. Obvious influences were observed on PHB fermentation when ammonia water feeding was stopped at different cell growth phases, and better results could be obtained when it was performed at 20 g/L to 30 g/L of residual biomass. Cell dry weight, PHB content and PHB concentration reached 61.9 g/L, 80.5% and 49.0 g/L, respectively under desired conditions.