Prophylactic supplement with melatonin successfully suppresses the pathogenesis of periodontitis through normalizing RANKL/OPG ratio and depressing the TLR4/MyD88 signaling pathway.

Periodontitis (PD) is an inflammatory disease characterized by gingival inflammation and resorption of alveolar bone. Impaired receptor activator of nuclear factor-kappa B ligand/osteoprotegerin (RANKL/OPG) signaling caused by enhanced production of pro-inflammatory cytokines plays an essential role in the pathogenesis of PD. Considering melatonin possesses significant anti-inflammatory property, this study aimed to determine whether prophylactic treatment with melatonin would effectively normalize RANKL/OPG signaling, depress toll-like receptor 4/myeloid differentiation factor 88 (TLR4/MyD88)-mediated pro-inflammatory cytokine activation, and successfully suppress the pathogenesis of PD. PD was induced in adult rats by placing the ligature at molar subgingival regions. Fourteen days before PD induction, 10, 50, or 100 mg/kg of melatonin was intraperitoneally injected for consecutive 28 days. Biochemical and enzyme-linked immunosorbent assay were used to detect TLR4/MyD88 activity, RANKL, OPG, interleukin 1ß, interleukin 6, and tumor necrosis factor-α levels, respectively. The extent of bone loss, bone mineral intensity, and calcium intensity was further evaluated by scanning electron microscopy, micro-computed tomography, and energy-dispersive X-ray spectroscopy. Results indicated that high RANKL/OPG ratio, TLR4/MyD88 activity, and pro-inflammatory cytokine levels were detected following PD. Impaired biochemical findings paralleled well with severe bone loss and reduced calcium intensity. However, in rats pretreated with melatonin, all above parameters were successfully returned to nearly normal levels with maximal change observed in rats receiving 100 mg/kg. As prophylactic treatment with melatonin effectively normalizes RANKL/OPG signaling by depressing TLR4/MyD88-mediated pro-inflammatory cytokine production, dietary supplement with melatonin may serve as an advanced strategy to strengthen oral health to counteract PD-induced destructive damage.

In vitro and in vivo osteogenesis of gelatin-modified calcium silicate cement with washout resistance.

The purpose of this study was to evaluate the physicochemical properties and the in vitro and in vivo osteogenesis of the newly developed calcium silicate containing 5 wt% gelatin (CSG) cement compared with calcium silicate (CS) and calcium sulfate hemihydrate (CSH) cements. In addition to the phase composition and microstructure, washout resistance, setting time, and diametral tensile strength of the bone cements were also performed. In vitro examination of cell growth, differentiation, and mineralization were performed with macrophage cell line (RAW 264.7), MG63 human osteoblast-like cells, and human mesenchymal stem cells (hMSCs). The mini-pig model with mandibular alveolar bone defect was used to assess the in vivo function of cement. Histological and histomorphometric assessments were performed at 6 and 12 weeks after implantation. The results indicated that the CS and CSG powders were mainly composed of poorly crystalline ß-dicalcium silicate, and the irregular CSH powders had a highly crystalline phase. After setting, the product of CS and CSG was calcium-silicate-hydrate gel and CSH exhibited a plate-like gypsum crystal structure. The setting time of CS, CSG, and CSH was 19, 35, and 10 min, respectively. Gelatin effectively improved the washout resistance and diametral tensile strength of CS from 2.4 MPa to 3.4 MPa, while CSH had no washout resistance and its strength was 7.6 MPa. The osteogenic activity of MG63 and hMSC cells on the CSG cement surface was consistently shown to be significantly higher than that on the CSH cement surface. Interestingly, CS and CSG cements exhibited lower macrophage expression compared to CSH cements. Twelve week after implantation, the amount of new bone in the defect area of the CS group was slightly higher than that of the CSG and CSH groups. It is concluded that CSG cement had improved anti-washout performance, favorable osteogenesis in vitro and in vivo, which was beneficial for clinical application.

An efficient and aseptic preparation of "sodium fluoride ((18)F) injection" in a GMP compliant facility.

INTRODUCTION: "Sodium fluoride ((18)F) injection" is an isotonic NaCl solution containing [(18)F]NaF to be used as bone imaging agent. Although its NDA was approved by the US FDA in 1972, it has not been commercially available since 1975 due to mostly the popularity of (99m)Tc-MDP. Recently, advances in PET/CT technology and the often interrupted (99m)Tc supply have led to the renewed interest in the use of [(18)F]NaF to detect bone metastases in cancer patients. This report introduces an efficient, low-cost and aseptic preparation of "Sodium fluoride ((18)F) injection" for PET scan. METHOD: (18)F-Fluoride in target water from cyclotron was adsorbed onto four different forms of anion-exchange resins then desorbed by isotonic NaCl solution into the product vial. One of the resins that yielded the product at the suitable pH was used for the aseptic preparation. The components for this setup, including stopcocks, extension tubes, etc., were all single-use, individually packed and sterile. The process was done in a lead-line isolator maintained in grade A (PIC/S) aseptic condition. The quality of the obtained "Sodium fluoride ((18)F) injection" was analyzed according to its monograph in the European Pharmacopoeia (EP). RESULTS: The resin in the chloride form yielded the product of pH 6.7 and was chosen for the subsequent preparation. The radiochemical yield was quantitative. The product met all criteria specified in EP, including biological, physical and chemical specifications. CONCLUSIONS: This method is an efficient, space-saving and extremely low-cost operation that easily performed in an aseptic environment meeting GMP standard. The quality of the "Sodium fluoride ((18)F) injection" so yielded meets EP specifications. This setup provides hospital with facility meeting GMP standard a cost effective and efficient method for "Sodium fluoride ((18)F) injection" production without the need for the expensive automatic module and extra QC instrument.