Regeneration of calvarial defects with Escherichia coli -derived rhBMP-2 adsorbed in PLGA membrane.

OBJECTIVE: Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) has been shown to be as effective as mammalian cell-derived BMP-2. However, several in vitro and in vivo experiments are still necessary to validate the effectiveness of E-BMP-2 due to the difference in synthesis process, mainly related to protein nonglycosylation. The objective of this study was to investigate whether biodegradable polylactide-co-glycolide (PLGA) membrane is a suitable carrier for E-BMP-2 delivery for bone regeneration of critical-sized defects in rat calvaria. MATERIALS AND METHODS: First, the osteoinductive effect of E-BMP-2 was confirmed in vitro in mouse bone marrow stromal cells by analysis of osteocalcin mRNA levels, and calcium deposition was detected by alizarin red staining. Before in vivo experiments, the release profile of E-BMP-2 from PLGA membranes was determined by ELISA. E-BMP-2 (0, 1, 5 and 10 µg/µl) was applied for ectopic and orthotopic bone formation and was analyzed by X-ray, micro-CT and histology. RESULTS: Release-profile testing showed that PLGA membrane could retain 94% of the initially applied E-BMP-2. Ectopic bone formation assay revealed that combination of E-BMP-2/PLGA membrane strongly induced bone formation. Stronger osteoinductivity with complete repair of critical-sized defects was observed only with PLGA membranes adsorbed with 5 and 10 µg/µl of E-BMP-2, whereas no bone formation was observed in the groups that received no membrane or 0-µg/µl dose of E-BMP-2. CONCLUSION: PLGA membrane was shown to be a suitable carrier for sustained release of E-BMP-2, and the E-BMP-2/PLGA membrane combination was demonstrated to be efficient in bone regeneration in a model of critical-sized defects.

E3710, a new proton pump inhibitor, with a long-lasting inhibitory effect on gastric acid secretion.

We have investigated the pharmacology of sodium (R)-2-[4-(2,2-dimethyl-1,3-dioxan-5-yl) methoxy-3,5-dimethylpyridin-2-yl]methylsulfinyl-1H-benzimidazol (E3710), a new proton pump inhibitor (PPI), and its effect on gastric acid secretion. E3710 irreversibly inhibited H(+),K(+)-ATPase activity in pig gastric vesicles with an acidic internal environment with an IC(50) of 0.28 microM. Administration of E3710 (0.1, 0.2, 0.4, and 0.8 mg/kg; n = 6) intraduodenally in a gastric fistula model in dogs inhibited histamine-stimulated gastric acid secretion at 0 to 2 and 24 to 26 h after administration with ED(50) values of 0.18 and 0.22 mg/kg, respectively. The inhibition by E3710 was 2.3 times more potent than that of another representative PPI, esomeprazole (0.2, 0.4, 0.8, and 1.6 mg/kg; n = 6) at 0 to 2 h after administration (ED(50) = 0.40 mg/kg) and 2.8 times more potent at 24 to 26 h (ED(50) = 0.71 mg/kg). In the gastric fistula dogs, the intragastric pH was >or=4 for 17% (n = 27) of a 24-h period with vehicle alone, but when E3710 was administered, at 0.2 (n = 4), 0.4 (n = 8), and 0.8 mg/kg (n = 5), the pH was >or=4 for 40, 79, and 88% of a day, respectively. The corresponding values for esomeprazole at 0.8 (n = 4) and 1.6 mg/kg (n = 8) were 55 and 59%, respectively. In a crossover study with vehicle, E3710 at 0.4 mg/kg and esomeprazole at 1.6 mg/kg (n = 6), E3710 increased the intragastric pH to >4 for 82% of a day compared with 61% of a day with esomeprazole. These results show that E3710 is a long-acting inhibitor of gastric acid secretion and a promising novel therapy for acid-related diseases, such as gastroesophageal reflux disease.

Amperometric biosensor for determining human salivary phosphate.

An amperometric biosensor was constructed for analysis of human salivary phosphate without sample pretreatment. The biosensor was constructed by immobilizing pyruvate oxidase (PyOD) on a screen-printed electrode. The presence of phosphate in the sample causes the enzymatic generation of hydrogen peroxide (H(2)O(2)), which was monitored by a potentiostat and was in proportion to the concentration of human salivary phosphate. The sensor shows response within 2s after the addition of standard solution or sample and has a short recovery time (2 min). The time required for one measurement using this phosphate biosensor was 4 min, which was faster than the time required using a commercial phosphate testing kit (10 min). The sensor has a linear range from 7.5 to 625 microM phosphate with a detection limit of 3.6 microM. A total of 50 salivary samples were collected for the determination of phosphate. A good level of agreement (R(2)=0.9646) was found between a commercial phosphate testing kit and the phosphate sensor. This sensor maintained a high working stability (>85%) after 12h operation and required only a simple operation procedure. The amperometric biosensor using PyOD is a simple and accurate tool for rapid determinations of human salivary phosphate, and it explores the application of biosensors in oral and dental research and diagnosis.