• Journal of Plant Biotechnology
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• v.47 no.3
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• pp.235-241
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• 2020

This is the first study to establish a complete protocol for micropropagation of Rehmannia glutinosa from root segments. The study involved investigating the effect of plant growth regulators on in vitro shoot regeneration and rooting and identifying substrates supporting survival and growth performance of ex vitro seedlings. A Murashige and Skoog (MS) medium containing 30 g/L sucrose for shoot induction and 0.2 mg/L indole-3-acetic acid (IAA), 1 mg/L 6-benzylaminopurine (BAP), and 1 g/L polyvinylpyrrolidone (PVP) for shoot multiplication resulted in the highest number of shoots per explant and shoot height. Applying a medium containing 0.5 mg/L IAA and 1 g/L PVP yielded optimal rooting of the shoots grown in vitro. Compost enriched with microbial inoculants and perlite enhanced seedling growth better than that with organic biofertilizer-free substrates (soil and sand). We recommend the continuous production of micropropagated R. glutinosa seedlings from root segments under the aforementioned conditions as a possible propagation technique for crops of this species.

• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.203-218
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• 1993

This study was designed to examine the effect of tetracycline application to the planed periodontal surgery of the experimentally induced periodontal disease in dogs. Modified Widman flap surgery was done and aqueous tetracycline (1%) was applied to the root surface for 5min, after which the wound was rinsed with saline, and flaps were coronally repositioned. Root surface ntoches were used as reference points. The animals were sacrificed 1 week, 2 weeks, 4 weeks, and 8 weeks after surgery, and block sections of tooth and surround tissue were processed for conventional light and electron microscopy. The results were as follows : 1. A more coronal position of junctional epithelium was observed in the area treated with tetracycline. 2. In the most of the tetracycline - treated teeth, the new collagen fibrils of connective tissue were oriented vertical/or oblique and parallel to the root surface. The vertical or oblique fibers were inserted into the denuded dentin matrix and contacted with exposed dentin collagen fibrils. 3. In the tetracycline - treated root, new cementum apposition, most of acellular extrinsic fiber cementum, was seen with bundles of oriented collagen fibrils incoporating into the cementum. 4. In the control and tetracyclin - treated teeth, bone resorption was observed at the alveolar crest in the 1 week groups.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.65.2-65
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• 2003

To protect the plant against several soil-borne pathogens, we are currently constructing disease-resistant transgenic root stock for the growth of cucurbitaceae vegetable plants, watermelon and gourd. We made a watermelon cDNA library from Cladosporium cucumerinum-Infected leaves for substractive hybriazation and differential screening. We isolated the several pathogen inducible cDNA clones, such as caffeoyl-CoA-methyltransferase, LAA induced protein, receptor-like kinase homolog, hydroxyproline-rich glycoprotein, catalase, calmodulin binding protein, mitochondrial ATPase beta subunit, methyl tRNA synthetase and WRKY transcription factors. We previously obtained CaMADS in pepper and galactinol synthase ( CsGolS) in cucumber that were confirmed to be related with disease-resistance. CaMADS and CsGolS2 were transformed into the inbred line 'GO701-2' gourd, the inbred line '6-2-2' watermelon and the Kong-dye watermelon by Agrobacterium tumerfaciens LBA4404. Plant growth regulators (zeatin, BAP and IAA) were used for shoot regeneration and root induction for optimal condition. Putative transgenic plants were selected in medium containing 100mg/L kanamycin and integration of the CaMADS and CsGO/S2 into the genomic DNA were demonstrated by the PCR analysis. We isolated major soil-borne pathogens, such as Monosporascus cannonballus, Didymella bryoniae, Cladosporium cuvumerinum from the cultivation area of watermelon or root stock, and successfully established artificial inoculation method for each pathogen. This work was supported by a grant from BioGreen 21 program, Rural Development Administration, Republic of Korea.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.4.1-4.10
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• 2019

Background: The mandibular third molar (M3) is typically the last permanent tooth to erupt because of insufficient space and thick soft tissues covering its surface. Problems such as alveolar bone loss, development of a periodontal pocket, exposure of cementum, gingival recession, and dental caries can be found in the adjacent second molars (M2) following M3 extraction. The specific aims of the study were to assess the amount and rate of bone regeneration on the distal surface of M2 and to evaluate the aspects of bone regeneration in terms of varying degree of impaction. Methods: Four series of panoramic radiographic images were obtained from the selected cases, including images from the first visit, immediately after extraction, 6 weeks, and 6 months after extraction. ImageJ software^® (NIH, USA) was used to measure linear distance from the region of interest to the distal root of the adjacent M2. Radiographic infrabony defect (RID) values were calculated from the measured radiographic bone height and cementoenamel junction with distortion compensation. Repeated measures of analysis of variance and one-way analysis of variance were conducted to analyze the statistical significant difference between RID and time, and a Spearman correlation test was conducted to assess the relationship between Pederson's difficulty index (DI) and RID. Results: A large RID (> 6 mm) can be reduced gradually and consistently over time. More than half of the samples recovered nearly to their normal healthy condition (RID ≤ 3 mm) by the 6-month follow-up. DI affected the first 6 weeks of post-extraction period and only showed a significant positive correlation with respect to the difference between baseline and final RID. Conclusions: Additional treatments on M2 for a minimum of 6 months after an M3 extraction could be recommended. Although DI may affect bone regeneration during the early healing period, further study is required to elucidate any possible factors associated with the healing process. The DI does not cause any long-term adverse effects on bone regeneration after surgical extraction.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.799-821
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• 1996

The ultimate goal of periodontal treatment has been to facilitate regeneration of diseased periodontal tissues, destroyed by inflammatory periodontal disease. For regeneration of the periodontium to occur, all of component tissues must be restored to their original position and architecture. Growth factors which were known to promote the cellular processes, ie, proliferation, migration and matrix synthesis, have been in the spotlight of current periodontics. Platelet-derived growth factor(PDGF) stimulates collagen and non collagen protein synthesis, migration and proliferation of periodontal ligament cells. Insulin-like growth factor(IGF) has potentials to induce collagen and bone matrix synthesis so that it regulates normal bone remodeling. Application of the combination have been known to facilitate formation of bone and cementum, and to synergistically interact to promote coronal migration and proliferation of periodontal ligament cells. These two growth factors have been reported to exhibit positive effect in the periodontally diseased teeth or class m furcation defects. The aim of the present study was to test the hypothesis that PDGF-BB alone or the combination of PDGF-BB and IGF-I can predictably enhance regeneration of the periodontium in the dehiscence defect. Following the resection of premolars, roots were embedded. After 12 weeks of healing period, standardized experimental $4{\times}4mm$ dehiscence defects were created on the mid-facial of the premolar roots in each of 4 young adult dogs. In control group, only methylcellulose gel was inserted in the defects. In experimental group I and II, gel with $2{\mu}g$ of PDGF-BB or $2{\mu}g$ of PDGF-BB and $1{\mu}g$ of IGF-I was inserted in the defects, respectively. At 8 weeks postsurgery, the dogs were sacrificed. The results were observed histologically and analyzed histomorphometrically.The results of this study were as follws. 1. The new cementum formation was $1.26{\pm}0.69mm$ in the control group, $1.80{\pm}0.84mm$ in the experimental group I, $1.93{\pm}0.51mm$ in the experimental group II. The experimental group III, the experimental group I, the control group were in the order of cementum formation without statistically significant differences between control and all experimental groups. 2. The new bone formation was $1.00{\pm}0.53mm$ in the control group, $1.53{\pm}0.63mm$ in the experimental group I, $l.33{\pm}0.45mm$ in the experimental group II. The experimental group I, the experimental group II, the control group were in the order of bone formation without statistically significant differences between control and all experimental groups. 3. The root resorption was $1.12{\pm}0.64mm$ in the control group, $1.34{\pm}0.73mm$ in the experimental group I, $0.79{\pm}0.59mm$ in the experimental group II without statistically significant differences between control and all experimental groups. These results suggested that the use of PDGF-BB alone or PDGF-BB and IGF-I in the dehiscence defects might facilitate periodontal regeneration in some degree, but has not shown statistically significant results.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.633-648
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• 1994

Synthetic bone graft materials have been used for the regeneration of periodontal tissue lost due to periodontal disease, but the limitations of these materials had prompted the use of composite grafts. Among those, a composite graft of calcium carbonate(CC) and calcium sulfate(CS) is one of those materials that has not been studied extensively. CC, which is extracted from a natural coral, is known to possess osteoconductive property. SC can play an adjunctive role in the regeneration of bone tissue, and has shown good resorbability and biocompatibility. This study was conducted in order to investigate the effects of CC and CS composite graft to the regeneration of bone in the intrabony defects of dogs. 3-wall intrabony defects ub size of $4mm{\times}4mm{\times}4mm$ were created in the alveolar bone in the premolar areas. Then those defects that were treated with root planning only were designated as control, while the experimental group 1 and 2 each received the CC and CS composite grafts in the ratio of 8 : 2 and 5 : 5 the animals were sacrificed after 8weeks and the specimens were histologically analyzed. The results were as follows ; 1. No inflammation or foreign body reaction were observed in all subjects. CS has not been seen due to complete resorption, and resorption pattern of CC was observed. 2. Significant differences(p<0.05) in new cementum formation were observed between control($1.42{\pm}0.64mm$) and experimental groups(group 1 ; $2.53{\pm}0.94mm$, group 2 ; $2.23{\pm}0.96mm$) but the difference between the two experimental groups was not significant. 3. Significant differences(p<0.01) in new bone formation were observed between control($0.59{\pm}0.55mm$) and experimental groups(group 1 ; $2.27{\pm}0.61mm$, group 2 ; $2.05{\pm}0.56mm$) but the difference between the two experimental groups was not significant. 4. The extent of apical epithelial migration has shown no significant difference between control($1.18{\pm}1.24mm$) and experimental groups(group 1 ; $0.51{\pm}0.54mm$, group 2 ; $0.73{\pm}0.70mm$). 5. The extent of bone formation was generally limited to the extent of cementum formation for all groups, and significant correlation was found in the amount of bone formation and cementum formation in experimental group 1.(Co.=0.86, p<0.01) These results suggest that the composite graft of CC and CS is biocomplatible and effective in the new bone and new cementum formations. In the case of 3-wall intrabony defects of dogs, the composite ratio of 8 : 2 and 5 : 5 had shown no significant differences in the healing.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.61-78
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• 1997

PDGF-BB has been recognized as a highly potential growth factor for guided tissue regeneration in periodontal defect. This study carried out histologic and histometric evaluation of $200ng/cm^2$ PDGF-BB loaded bioresorbable membrane made from polyglycolic and polylactic acid. It was tested for its biocompatibility, ability to prevent epithelial downgrowth and amount of periodontal regeneration. Without membrane and PDGF-BB unloaded bioresorbable membrane were used as control. Healthy six beagle dogs were used. Each dog was anesthetized and buccal flaps were reflected in the mandibular and maxillary premolar areas. Buccal alveolar bone between the mesiobuccal and distobuccal line angles was surgically removed on the lower 2nd and 4th premolar in mandible, 2nd premolar in maxilla, to a level 4mm apical to the cementoenamel junction with creating a Class II buccal furcation defect for available space. Care was taken not to remove the root cementum layer and rubber impression materials were placed over each surgically created defect. Flaps were repositioned and sutured. Reconstructive surgery was performed 1 month after defect preparation. PDGF-BB loaded membranes and controls were randomly placed on maxillary 2nd premolars and mandibular 2nd and 4th premolars. Plaque control regimen was instituted with daily brushing with a 0.1% chlorhexidine digluconate during experimental periods. The animals were sacrificed 2 and 5 weeks after surgery and undecalcified specimens were prepared for histologic evaluation. The degree of coronal regrowth of new bone, new cementum and the amonut of new bone areas formed on the defected area of the PDGF-BB loaded membrnae turned superior to without membrane and drug unloaded membrane. Experimental membrane could prevent the epithelial downgrowth irrespective of drug loaded or not and showed good biocompatiblity, These results implicated that PDGF-BB loaded bioresorbable membrane could be highly useful tool for guided tissue regeneration of periodontal defects.

• Korean Journal of Plant Resources
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• v.20 no.4
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• pp.367-374
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• 2007

This study was carried out to establish the micropropagation system of Bupleurum latissimum Nakai that is a Korean native endangered species. Callus were induced from the leaf, petiole and floral bud and the percentage of callus formation was highest in the floral bud on the MS medium containing 2.0 mg ${\cdot}$ $L^{-1}$ 2,4-D. Especially, callus induced from floral bud was formed 77.8% and the percentage of shoot formation was 42.6% on the MS medium containing 2.0 mg ${\cdot}$ $L^{-1}$ 2,4-D plus 1.0 mg ${\cdot}$ $L^{-1}$ TDZ. For simultaneously callus formation and shoot regeneration, 1/2 MS medium was more effective than MS medium. The percentage callus formation, shoot regeneration and rooting were 46.3%, 13.0%, 13.0% in 1/2 MS medium, respectively. Soot regeneration from callus was good in 1/2 MS medium supplemented with 2.0 mg ${\cdot}$ $L^{-1}$ 2,4-D plus 1.0 mg ${\cdot}$ $L^{-1}$ BA where percentage of shoot regeneration was 74.1 %, and the number of shoot per explant was 2.4. The percentage of rooting was lowest (57.8%) in control while it was highest (97.8%) in 1.5 mg ${\cdot}$ $L^{-1}$ NAA. In acclimatization of regenerated plantlets, the percentage of survived plantlets was highest (86.1%), and plant height, root length and fresh weight were good in the soil for horticulture.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.51-59
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• 2014

In this study, we developed a high frequency watermelon regeneration system using three breeding lines ('B02', 'B05' and 'D04') of watermelon (Citrullus lanatus (thunb.) Matsum. & Nakai) which are differed in their fruits in shape, color of pericarp and flesh. The highest frequency of explants with callus was observed by using explants that consist of cotyledon proximal part end in all breeding lines, and the highest rate of callus induction was obtained on MS medium containing 1.0 mg/L BAP + 0.5 mg/L IAA for 'B02' (94%), 3.0 mg/L BAP for 'B05' (95%), 3.0 mg/L BAP + 0.1 mg/L IAA for 'D04' (90%). The highest shoot regeneration rates from derived callus were obtained on MS medium containing 1.0 mg/L BAP + 0.5 mg/L IAA for 'B05' (94%), and then a 'B02' (81%) with a same culture conditions, and the lowest regeneration was obtained on MS medium containing 1.0 mg/L BAP for 'D04' (56%). Regenerated plants showed the best rates of root formation on MS containing 0.1 mg/L IBA for 'B02' (67%), 0.1 mg/L NAA for 'B05' (87%), 0.5 mg/L IAA for 'D04' (88%). The regenerated plants showed a 100% survival rate in soil condition. The tissue culture and regeneration conditions obtained from this study will be useful for regenerating plants in breeding applications, and will be a useful tool for further genetic transformation studies on watermelons.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.4
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• pp.39-61
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• 2008

Objectives : The present study was performed to investigate whether acupuncture stimulation in the rats affected regeneration properties of the injured sciatic nerve. A differential effect of acupuncture stimulation on the one point near the spinal nerve root controlling sciatic nerve activity and the other point in the peripheral area subordinated by injured nerve was compared. Materials and Methods: Rat sciatic nerves were injured by crush, and the effects on axonal regeneration on injured sciatic nerves were evaluated by acupuncture stimulation at two different regions. In proximal acupuncture stimulation group, acupuncture stimulation was performed on Huatuo Jiaji(EX B2) points located from L5 to S1 vertebral levels to stimulate the nearest spinal nerve root that innervates sciatic nerves. In distal acupuncture stimulation group, acupuncture stimulation was performed on Zusanli(ST 36) and Weizhong(BL 40) points to stimulate at peripheral area dominated by injured sciatic nerves. Acupuncture stimulation was given every other days for 1 or 2 weeks. Sciatic nerve tissues collected from acupuncture stimulation experimental groups, injury control group, and intact animal group were used for protein analysis by Western blotting or Hoechst nuclear staining. To determine axonal regeneration, Dil fluorescence dye was injected into the sciatic nerve 0.5 cm distal to the injury site in individual animal groups and Dil-labeled cells by retrograde tracing were measured in the DRG at lumbar 5 or in the spinal cord. DRG sensory neurons prepared from individual animal groups were used to measure the extent of neurite outgrowth and for immunofluorescence staining with anti-GAP-43 antibody. Results : Animal groups given proximal or distal acupuncture stimulation showed upregulation of GAP-43 and Cdc2 protein levels in the sciatic nerve at 7 days after injury. Cdk2 protein levels were strongly induced by nerve injury, but did not show changes by acupuncture stimulation. Phospho-Erk1/2 protein levels were elevated by acupuncture stimulation above those present in the injury control animals. These increase in regeneration-associated protein levels appeared to be related with increase cell proliferation in the injured sciatic nerves. Hoechst 33258 staining of sciatic nerve tissue to visualize nuclei of individual cells showed increased Schwann cell number in the distal portion of the injured nerve 7 and 14 days after injury and further increases by acupuncture stimulation particularly at the proximal position. Measurement of axonal regeneration by retrograde tracing showed significantly increased Dil-labeled cells in proximal acupuncture stimulation group compared to distal acupuncture stimulation group and injury control group. Finally, an evaluation of axonal regeneration by retrograde tracing showed increased number of Dil labeled cells in the DRG at lumbar 5 or in the ventral horn of the spinal cord at lower thoracic level at 7 days after nerve injury. Conclusions : The present data show that the proximal acupuncture stimulation at Huatuo Jiaji(EX B2) points governing injured sciatic nerves was more effective for axonal regeneration than the distal acupuncture stimulation. Further studies on functional recovery or associated molecular mechanisms should be critical for developing animal models and clinical applications.