• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.71-80
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• 2005

Effects of low temperature ($8^{\circ}C$) on the hydraulic conductivity of young roots of a chilling-sensitive (cucumber; Cucumis sativus L.) and a chilling-resistant (figleaf gourd; Cucurbita ficifolia Bouche) crop have been measured at the levels of whole root systems (root hydraulic conductivity, $Lp_r$) and of individual cortical cells (cell hydraulic conductivity, Lp). In figleaf gourd, there was a reduction only in hydrostatic $Lp_r$ but not in osmotic $Lp_r$ suggesting that the activity of water channels was not much affected by low root temperature (LRT)treatment in this species. Changes in cell Lp in response to chilling and recovery were similar asroot level, although they were more intense at the root level. Roots of figleaf gourd recovered better from LRT treatment than those of cucumber. In figleaf gourd, recovery (both at the root and cell level) often resulted in Lp and $Lp_r$ values which were even bigger than the original, i.e. there was an overshoot in hydraulic conductivity. These effects were larger forosmotic (representing the cell-to-cell passage of water) than for hydrostatic $Lp_r$. After a short term (1 d) exposure to $8\;^{\circ}C$ followed by 1 d at $20\;^{\circ}C$, hydrostatic $Lp_r$ of cucumber nearly recovered and that of figleaf gourd still remained higher due to the overshoot. On the contrary, osmotic $Lp_r$ and cell Lp in both species remained high by a factor of 3 as compared to the control, possibly due to an increased activity of water channels. After pre-conditioning of roots at LRT, increased hydraulic conductivitywas completely inhibited by $HgCl_2$ at both the root and cell levels. Different from figleaf gourd, recovery from chilling was not complete in cucumber after longer exposure to LRT. It is concluded that at LRT, both changes in the activity of aquaporins and alterations of root anatomy determine the water uptake in both species. To better understand the aquaporin function in plants under various stress conditions, we examined the transgenic Arabidopsisand tobacco plants that constitutively overexpress ArabidopsisPIP1;4 or PIP2;5 under various abiotic stress conditions. No significant differences in growth rates were found between the transgenic and wild-type plants under favorable growth conditions. By contrast, overexpression of PIP1;4 or PIP2;5 had a negative effect on seed germination and seedling growth under drought stress, whereas it had a positive effect under cold stress and no effect under salt stress. Measurement of water transport by cell pressure probe revealed that these observed phenotypes under different stress conditions were closely correlated with the ability of water transport by each aquaporin in the transgenic plants. Together, our results demonstrate that PIP-type aquaporins play roles in seed germination, seedling growth, and stress response of Arabidopsis and tobacco plants under various stress conditions, and emphasize the importance of a single aquaporin-mediated water transport in these cellular processes.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.399-408
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• 1995

The purpose of this study was to obtain information on the clinical and radiographic features of the dentigerous cysts in the jaws. For this study, the authors examined and analysed the clinical records and radiographs of 233 patients who had lesions of dentigerous cyst diagnosed by clinical and radiographic or histopathological examinations. And the obtained results were as follows: 1. Dentigerous cysts occurred the most frequently in the 2nd decade(38.2％) and occurred more frequently in males(67.4％) than in females(32.6％). 2. The most common clinical symptom was swelling of the jaw(33.9％), and the lesions were treated by the method of surgical removal. 3. The type of lesions was mainly observed as central type(72.5％), and size of the lesion was most frequently observed 2 - 2.9cm in the widest length. 4. The lesions were most frequently observed well-defined outline with hyperostotic border(49.8％), and smooth margin(73.4％), and homogeneous lesional radiolucency(79.4％). 5. Cortical thinning and expansion of the lesions(82.0％) were observed, and their direction were most frequently observed toward buccal side(64.0％). 6. The effect on the causative tooth were observed as tooth displacement(41.2％) and delayed root development(l9.3％), and the distance between cemento-enamel junction and lesional wall attachment of the causative tooth was mainly observed as below 2mm(79.6％). 7. The effect on the adjacent tooth were observed as loss of lamina dura(66.8％), root resorption(33.9％), and tooth displacement(31.5％). 8. The effects on the adjacent anatomic structures were observed as displacement of the mandibular canal(46.5％) and maxillary sinus or nasal cavity(72.2％).

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.128-137
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• 2011

Purpose: Resonance frequency analysis, Periotest, and removal torque (RT) test were known as the methods to assess implant stability. The results of these methods are affected by the bone condition, implant diameter and shape. The purpose of this study is to access the meaning and the correlationship of the resonance frequency analysis, Periotest and RT test in osseointegration simulated acrylic resin when the engaged bone thickness and peri-implant bone defect are changed. Materials and methods: To simulate osseointegration, the fixture was fixed to an aluminum mold with a screw. Acrylic resin powder and liquid were poured into the mold for polymerization. The engaged resin thickness with implant was controlled. Simulated cortical bone thicknesses were 1, 3, 5 and 10 mm. Additional 1, 3 and 5 mm peri-implant bone defects were simulated. Three types of implants were used; 4 mm diameter implants of straight shape, 4 mm diameter implants of tapered shape and 5 mm diameter implants of tapered shape. Five fixtures per each type were tested in respective bone condition. Resonance frequency analysis and Periotest were evaluated in all bone conditions. Peak removal torque was measured at simulated cortical bone thicknesses of 1 and 3 mm. The statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, and Spearman test using a 95% level of confidence. Results: With increasing engaged bone depth, the Implant Stability Quotient (ISQ) values increased and the Periotest values (PTVs) decreased (P<.001, P<.001). With increasing peri-implant bone defect, ISQ values decreased and PTVs increased (P<.001). When the diameter of implant increased, ISQ values increased and Periotest values (PTV) decreased (P<.001). There was a strong correlation between ISQ values and PTVs (r = -0.99, P<.001). Furthermore, the peak removal torque values had weak correlations with both ISQ values and PTVs (r = 0.52, P<.001 ; r = -0.52, P<.001). Conclusion: This study confirmed favorable implant stability with increasing engaged bone depth and implant diameter and decreasing peri-implant bone defect. ISQ values and PTVs showed strong correlation with each other and not with the peak removal torque values.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.2
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• pp.179-195
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• 2010

In the internal connection system, the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. The purpose of this study was to assess the loading distributing characteristics of three different abutments for GS II$^{(R)}$ implant fixture(Osstem, Korea) under vertical and inclined loading using finite element analysis. Three finite element models were designed according to three abutments; 2-piece Transfer$^{TM}$ abutment made of pure titanium(GST), 2-piece GoldCast$^{TM}$ abutment made of gold alloy(GSG), 3-piece Convertible$^{TM}$ abutment with external connection(GSC). This study simulated loads of 100N in a vertical direction on the central pit(load 1), on the buccal cusp tip(load 2) and $30^{\circ}$ inward inclined direction on the central pit(load 3), and on the buccal cusp tip(load 4). The following results were obtained. 1. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture and lower stress was taken at the cancellous bone. 2. When off-axis loading was applied, high stress concentration observed in cervical area. 3. GSG showed even stress distribution in crown, abutment and fixture. GST showed high stress concentration in fixture and abutment screw. GSC showed high stress concentration in fixture and abutment. 4. Maximum von Mises stress in the surrounding bone had no difference among three abutment type. In GS II$^{(R)}$ conical implant system, different stress distribution pattern was showed according to the abutment type and the stress-induced pattern at the supporting bone according to the abutment type had no difference among them.

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.25-30
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• 2004

Purpose: Several panoramic indices have been suggested to assess bone quality from the morphology and width of mandibular cortex on panoramic radiography. The purpose of this study was to compare dental implant failure group with control group in panoramic mandibular index (PMI), mandibular cortical index (MCI), and gonion index (GI) and to determine the effect of these panoramic indices on dental implant failure. Materials and Methods: A case-control study was designed. Test group (n=42) consisted of the patients who had their implants extracted because of peri-implantitis. Control group (n=139) consisted of the patients who retained their implants over one year without any pathologic changes and had been followed up periodically. They had dental implants installed in their mandibles without bone augmentation surgery from 1991 to 2001. The following measures were collected for each patients: 1) PMI, MCI, and GI were measured twice at one-week interval on preoperative panoramic views; and 2) age, sex, implant length, implant type, installed location, occluding dentition state, and complication were investigated from the chart record. Results: The PMI showed moderate level of repeatability. The intra-observer agreement of MCI and GI were good. There was statistically significant difference in PMI between two groups. There were significant different patterns of distribution of MCI and GI between two groups. Among the panoramic indices, PMI and MCI showed significant correlation with dental implant failure. Conclusion: Panoramic indices can be used as reference data in estimating bone quality of edentulous patients who are to have implants installed in their mandibles.

• Journal of Life Science
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• v.9 no.2
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• pp.127-135
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• 1999

Gentiana scabra Bunge var buergeri Max, can be widely used such as cut-flower, ornamental and medicinal plant among the native plants. Microscopic and Scanning electron microscopic observation plant were carried out to estimates the characteristics correlated with germinability and germination process, and the results were as follows. The seeds were germinated just after harvest, and it means that there is no or little dormancy of the seeds. Matured seeds showed higher germinability than those of immatured. As the storage period was longer, immatured seeds showed shorter longevity than those of matured. The average longevity was about 190 days. According to the observation results of morphological changes during the germination, seed coat was expanded with water absorption immediately after seeding, and radicals were observed 2 days after seeding. Root hairs were formed behind the growing tip of the root on 4 days after seeding and cotyledon were unfolded on 6 days after seeding. In the microscopic observation of leaf tissues, it could be easily distinguished between midrib, and leaf blade, and also observed upper epidermis, palisade parenchyma and spongy parenchyma consisted as a sing1e layer. Palisade parenchyma was consisted of a single layer of cell. Stomata were restricted lower surface, arranged as anamocytic type, and surrounded by guard cells. In the microscopic anatomy of stem were consisted of cortical layer, forming a single layer of epidermis and parenchyma, and vascular bundle which was consisted of continuous cylinder of vascular tissues.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.691-694
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• 2010

Purpose: Central giant cell granuloma is a rare, benign giant cell tumor which commonly develops in areas near the teeth. It accounts for approximately less than 7% of benign tumors of the mandible. Clinically, central giant cell granuloma is classifed into aggressive and non-aggressive type, and usually requires surgical treatment. There has been no report of central giant cell granuloma in plastic surgery field of the country, and we report a case with a brief review of the diagnosis and treatment of the disease. Methods: A 23-year-old male presented with a hard, non-tender, growing mass with the size of $4.0{\times}3.0\;cm$ on mandible for several months. Computed tomography scan showed a solid mass within thinned outer cortex on mandible. The thinned outer cortex was excised with the mass and the inner cortex was partially removed burring. After the tumor removal, mandible was fixed by reconstruction plate. Results: Pathologic report showed numerous large multinucleated giant cells, diffusely distributed in a background of ovoid-to-spindle-shaped mononuclear cells. There was no evidence of recurrence after 1 year follow up. Bony defect was regenerated and we removed the reconstruction plate. Conclusion: Removal of central giant cell granuloma results in defect of outer cortex, which can be reconstructed by using reconstruction plate, autologous bone graft or bone cement. We used reconstruction plate as a conservative method to induce secondary healing of the outer cortical defect area, which resulted in normal mastication and occlusion with no recurrence.

• Journal of Korean Neurosurgical Society
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• v.30 no.1
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• pp.26-32
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• 2001

Objective : The increasing use of sensitive neuroimaging techniques has demonstrated that significant percentage of patients with intractable complex partial seizures have brain masses, especially in temporal lobe. The optimal surgical solution for these patients is still open to debate. The purpose of our investigation is to evaluate the surgical outcome of patient with lesion-related temporal lobe epilepsy with respect to the types of surgery and the location of lesion. Patients and Methods : From DEC. 1993 to Dec. 1997, 35 patients with intractable epilepsy and space occupying temporal lobe lesion identified in preoperative MRI were included in this study. The types of surgery were lesionectomy, anterior temporal lobectomy with or without hippocampectomy. The location of lesion was divided as anteromedial group and lateral cortical group. The postoperative seizure outcomes according to the type of surgery and location of the lesion were compared. Results : Twenty-six of 34 patients(76.5%) were seizure-free after surgery. The Engel's class was favorable after anterior temporal lobectomy with or without hippocampectomy(p=.044) Conclusion : It is favorable to perform anterior temporal lobectomy for the treatment of intractable epilepsy with space-occipying lesion in temporal lobe. The resection of the hippocampus can be individualized.

• Journal of Korean Neurosurgical Society
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• v.61 no.3
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• pp.363-375
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• 2018

Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal age-adjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.

• Clinical and Experimental Pediatrics
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• v.49 no.5
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• pp.529-532
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• 2006

Purpose : To study the spectrum of epilepsy in children with cerebral palsy. Methods : A total of 93 consecutive patients with cerebral palsy(CP) were retrospectively suited. Criteria for inclusion were a follow-up period of at least 2 years. The study examined the correlation between the incidence of epilepsy and seizure types in the different forms of CP. Other factors associated with epilepsy, such as age of first seizure, occurrence of abnormalities on brain imaging, and electroencephalogram were also analyzed. Results : The overall prevalence of epilepsy in children with CP was 46.2 percent. The incidence of epilepsy was predominant in patients with mixed, diplegic, and quadriplegic palsies : 55.5 percent, 51.6 percent, and 50.0 percent in frequency. The first seizure occurred during the first year of life in 48.8 percent of patients with epilepsy. Generalized tonic-clonic seizures were the most common seizure type(44.2 percent), predominant in diplegic patients(64.3 percent). On the other hand, infantile spasms and myoclonic seizures were the main cause of seizures among quadriplegic children(60 percent and 40 percent, respectively). The occurrence of epilepsy was more popular in the group with abnormal brain imagings; especially encephalomalacia and cortical atrophy. All children with epilepsy in this study showed abnormal electroencephalogram(EEG) findings: Generalized abnormalities were observed in 55.8 percent of children with epilepsy; more dominantly in quadriplegic children(80.0 percent); and 40 percent of children with diplegia showed focal abnormalities. Conclusion : Cerebral palsy is associated with a higher incidence of seizure disorders, which, in the majority, has its onset in the first year of life; brain imaging and EEG are most effective in spotting epilepsy in children with CP.