• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.6
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• pp.498-510
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• 2001

Distraction osteogenesis refers to the biological process responsible for new bone formation between bone segments by gradual distraction after osteotomy. For the past several years, various inconveniences including a protracted consolidation period that requires patients to wear a distractor frame longer, as well as higher medical costs, have not been remedied by improvements in osteotomy, distraction rate and monitoring system. Furthermore, side effects such as pin tract infections and soft tissue swelling may arise due to the long treatment period. These drawbacks form the rationale of this study which purports to seek a method by which the consolidation period can be reduced. This paper examines how platelet-rich plasma(PRP), known to facilitate osteogenesis, influences bone formation when applied in distracted area. Ten mongrel dogs, which were made to wear external distractor frames after osteotomy in both sides of the mandible, were used as subjects. After a 7day period of latency, distraction was carried out at a rate of 1mm/day for 14 consecutive days. After the onset of distraction, 2ml of PRP and a mixture of calcium gluconate and thrombine were injected into the center of the distracted callus on the left side of the mandible. The left was injected with PRP while the right side was set as the control site without PRP treatment. Execution at the onset of distraction and in 2 weeks, 4 weeks and 8 weeks after the consolidation period, clinical and radiographic tests, bone mineral density examination, histological examination and histomorphometric analysis were conducted to compare both sides. The results are summarized as follows: 1. Based on the clinical examination at two weeks, more remarkable cortical bone formation was found on the buccal and lingual side of the distracted area in the PRP treatment site than in the control site. No visual difference was found between the PRP treatment site and the control site at four eight weeks. 2. Based on the radiological examination, a distinct increase in the radiopaque appearance of the PRP treatment site was revealed at two weeks, but this increase appeared to slow down at four and eight weeks. 3. Examination of bone mineral density revealed a significant difference at two weeks with the PRP treatment site yielding density two times higher than the control site. This difference lessened after four weeks, and disappeared at eight weeks. 4. The histomorphometric examination revealed that about 20% more bony trabeculae area(20%, higher) was formed in the PRP treatment site than in the control site. In conclusion, it can be said that PRPs effect on stimulating bone formation in the PRP treatment site manifest as early as two weeks. Trabeculae formation likewise increased throughout the whole period. If this result can be applied to humans, the consolidation period can be reduced by injecting PRP into the distracted area.

• Journal of Life Science
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• v.18 no.6
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• pp.878-883
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• 2008

Aeromonas hydrophila DA33 was isolated from cultivated soils as a bacteria having high abilities to solubilize inorganic phosphate. Glucose dehydrogenase gene (gdh) was cloned from Escherichia coli. The recombinant plasmid, pGHS containing glucose dehydrogenase gene was introduced into A. hydrophila DA33 in order to improve the activity of phosphate-solubilizing. The transformant harboring the gdh gene, A. hydrophila pGHS/DA33 increased enzyme activity. The strain also increased the gluconic acid generation that was effective for phosphate solubilization. It was possible that the strain containing pGHS produced higher solubilized phosphate with tri-calcium phosphate as the unique (P) source, in comparison with that of wild type without plasmid. These results suggest that the strain, A. hydrophila pGHS/DA33 is expected as effective biofertilizer for phosphate solubilization.