• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.285-293
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• 2007

The study was to determine zonal characteristics of nutrients and chlorophyll and evaluate their trophic relations in Daechung Reservoir. For this study, we compared longterm water quality data among three zones along with trophic state using 1993 to 2002 dataset, obtained from the Ministry of Environment, Korea. Total phosphorous (TP), Secchi depth (SD) and chlorophyll (CHL) showed typical longitudinal declines from the riverine to lacustrine zone, but total nitrogen (TN) was not evident. Largest seasonal variations in TP and CHL occurred during the summer monsoon from July to August. In the reservoir, ambient TN averaged 1.67 mg $L^{-1}$ and ratios of TN : TP averaged 88.04, indicating that nitrogen is not likely limited but phosphorus limitation was evident. Trophic State Index (TSI), based on CHL, TP, and SD, varied depending on the zones and seasons. Mean TSI (TP) in the riverine zone was 62 during the monsoon, indicating a hypertrophic condition, whereas the mean was 40 in the lacustrine, indicating a nearly oligotrophic. Values of TSI (CHL) showed maximum in the transition zone during the monsoon. The deviation analysis of TSI showed that about 65% of TSI (CHL)-TSI (TP) and TSI (CHL)-TSI (SD) values were less than zero and the lowest values were -42, indicating an effect of inorganic turbidity on algal growth in the reservoir. Correlation analysis of CHL vs. SD shewed greater correlation coefficient (p<0.001, r=-0.47) in the transition than other two zones (p<0.001, $r{\leq}-0.40$). Correlation analysis of TP vs. CHL was greatest in the lacustrine and TP was minimum in the lacustrine zone, indicating a lowest yield of algal biomass in the lacustrine. Overall data suggests that zonal response of chlorophyll yield at a given nutrient unit is clearly differed among the longitudinal gradients, so the management strategy such as cross sectional modelling should be provided in each zone.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.543-549
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• 2008

Distraction osteogenesis is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint(TMJ) have not been well documented. The TMJ is one of the most complex joint in the body and is composed of a fibrous surface layer, a proliferative zone, hypertrophic cartilage, and bone. The shape and role of the TMJ change and modify during a person's life-time. Possible complications that can arise after mandibular distraction include failure of the formation, failure of callus, infection, disturbance of TMJ and of occlusion. However, there are only a few reports on changes in the TMJ as a result of distraction osteogenesis. Hence, the goal of this study was to evaluate the change of the TMJ after experimental distraction of mandibular ramus in rabbit. We studied histological changes of mandibular condyle, articular disk and retrodiscal tissue, and also examined the collagen I gene expression and MMP-1 gene expression. The results were as follows. 1. In the histological staining, experimental condylar surface showed more thick fibrous articular layer and proliferative layer, compared with the control condyle and experimental articular disc showed thick and dense collagen fibers compared with the control disc. 2. In the collagen I and MMP-1 gene RT-PCR analysis, experimental discs showed increased collagen I expression compared with the control disc, while MMP-1 gene expression was decreased compared with the control disc. The retrodiscal tissue was almost equal expressions of the collagen I and MMP-1 genes compared with the control retrodiscal tissue. These findings suggest that histological and biomolecular changes occur in condyles and discs after unilateral mandibular distraction osteogenesis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.130-152
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• 1989

The purpose of this study was to observe the effect of intermaxillary fixation on the chondrocytes of the mandibular condyle under the light and the electron microscope. For this study, twenty rabbits were placed in maxillomandibular fixation, and two were used as a control group. The experimental group was subdivided into 3, 7, 14, 21 and 28 day group. After the experimental period of 3, 7, 14, 21 and 28 days, the animals were sacrificed with a vascular perfusion of 2.5% glutaraldehyde. The condylar processes were exenterated, and decalcified in 0.1M EDTA with 2.5% glutaraldehyde solution for two weeks. The specimens were rinsed with phosphate buffer solution and the post-fixation was carried out with 2% osmium tetroxide at $4^{\circ}C$ for two hours. Thereafter the specimens were dehydrated in alcohol series, cleared with propylene oxide and embedded in Epon 812 resin. Thin sections and ultra-thin sections were made, and the cellular structures of the condylar cartilages were observed with light and electron microscope. The results were as follows: 1. In the intermaxillary fixation group, the cartilaginous tissues of mandibular condyles showed a marked decrease in the thickness compared to the control group. 2. A remarkable change was noticed in the proliferating and the hypertrophic zone of the condylar cartilages in the experimental group. 3. An atrophic change of the condylar cartilage was appeared in the 3 day experimental group and degenerative change was observed in the 7 day experimental group, and recovery was seen in thereafter 14 day experimental group. 4. Calcification, degeneration and resorption of condylar cartilage were recognizable, and the cellular zone of the condylar cartilage was appeared indistinctly in 3 day and 7 day experimental group. The chondroblasts, however, were differentiated into chondrocytes and resumed mitosis, and then the cellular zones of the condylar cartilage were reorganized from the 14 day experimental group under the findings of light microscope. 5. Under the findings of electron microscope, atrophic changes and decrease in number of intracellular organelles, degenerative changes of cytoplasm, and pyknosis of nuclei were observed in early stage, however, a gradual regeneration and reorganization of the intracellular organelles were observed from 14 day experimental group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.25 no.4
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• pp.337-349
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• 1999

The extracellular matrix(ECM) is a complex network of different combination of collagens, glycosaminoglycans, laminin, fibronectin, and many other glycoproteins including proteolytic enzymes. The composition and organization of the ECM contributes to the uniques physical or biomechanical properties of a tissue. Fibronectins(FN) are dimeric glycoproteins located on cell surfaces, in the matrix of connective tissue, and in blood. Fibronectins mediate cell attachment to collagen substratum and have been implicated in a variety of important biological processes, including embryogenesis and cell differentiation. The purpose of this study was to determine the effects of surgical induction of anterior disk displacement(ADD) on distribution of fibronectin in the rabbit temporomandibular joint(TMJ) tissues included the articular cartilage, disc, retrodiscal tissue, articular eminence using an immunohistochemical technique. The left TMJ was exposed surgically, and all discal attachments were severed except for the posterior attachment. The disk was then repositioned anteriorly and sutured to the zygomatic arch. The right TMJ served as a shamoperated control. Normal joints were used as a nonoperated control. Fourty-five rabbits were used for experiments in total. For fibronectin immunohistochemical study, eighteen rabbits (one normal group and 5 experimental groups, each group consists of 3 rabbits) were used. The experimental rabbits were sacrified after operation period of 2, 3, 4, 6 and 8 weeks on fibronectin. The obtained results were as follows ; 1. Fibronectin immunoreaction on all TMJ tissues(mandibular condyle, articular disc, retrodiscal tissue, articular eminence) in the normal rabbit was observed. Especially the reverse cell layer and proliferation zone of articular cartilage of condyle show strong positive reaction. 2. Depletion of fibronectin in the all TMJ tissues except hypertrophic zone of articular cartilage occurred at 2 weeks following induction of ADD. 3. The restoration of immunoreaction at 4 weeks was observed and a progressive increasing reaction at 6 weeks, 8 weeks also was found. Our study generally showed degenerative changes in TMJ tissues after ADD although TMJ tissues adapted or degenerated to abnormal loads and stress distribution according to the remodeling capacity of TMJ tissues.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.285-294
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• 1991

The human temporomandibular joint as a ginglymoarthrodial one has much in common with the other synovial joints of the body, but it does possess an unique charachteristic in that it must accomodate the various occlusal relations of dentition during an end point of closure. For that reason, the movement of the condyle in the temporomandibular joint is susceptible to influences from the nature of occlusion. Undue loading to the temporomandibular joint can be applied on the occasion of premature contacts in centric relation, balancing side interferences, change of occlusal surfaces due to excessive attrition, loss of tooth. Such occlusal disharmonies in association with the systemic and emotional factors may give rise to the temporomandibular disorder. On the other hand, the changes of occlusal patterns in the growing body can also have an effect on the growth of the temporomandibular joint through the alterations of functional stresses. The purpose of this study was to observe histopathologic response of the temporomandibular joint in unilateral chewing on one side exclusively for 10 months. Three dogs showing normal masticatory function were chosen. One dog aged about 12 months was for control, two dogs for experimental specimens were about 12 and 18 months old respectively. For chewing on the left side only, unilateral lower right premolar and molar were extracted in two experimental specimens. And then three dogs were sacrificed 10 months later. Frontal histologic sectioning of joints were done for the observation of the effects of one-side chewing. 24 specimens from three dogs were obtained and fixed in 10% formalin and routinly processed with H-E staining for histologic examination. The light microscopic findings were interpretated as follows: 1. Experimental specimen 1 aged about 22 months: In comparison with control and right non-chewing side, the proliferative and hypertrophic zone were increased at the mesial and lateral part of left chewing side condyle. There was no change of the articular tissue of temporal bone. 2. Experimental specimen 2 aged about 28 months: The articular tissues of adult joint were observed. The differences between the chewing and non-chewing side were not seen in the articular tissues of condyle and temporal bone.

• The Korea Journal of Herbology
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• v.25 no.1
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• pp.75-81
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• 2010

Objectives : It was investigated new herbal prescription HT005 supported by traditional Korean medicine has a activity on the longitudinal bone growth of rats. HT005 were consisted of the root of Angelica sinensis, the fruit of Alpinia oxyphylla, the root of Astragalus membranaceus, the stem of Eleutherococcus senticosus, and the root of Dioscorea japonica, and Poria cocos. Method : To investigate the effect on longitudinal bone growth in adolescent male Sprague-Dawley rats, the longitudinal length of growth plate was measured directly by the tetracycline fluorescent labeling method and chondrocyte staining method. HT005 administered orally for four days, and the tetracycline was injected twice on the growth plate of the animals for fluorescent dying. The rate of longitudinal bone growth was measured the length between the tetracycline bands which fixed on the 3rd day and 5th day after injection. Cresyl violet was also used to stain the chondrocytes in the growth plate. The length of growth plate after administration was compared. Expression of IGF-1 and BMP-2 in the growth plate was investigated by immunohistochemistry. Results : HT005 showed a significant longitudinal bone growth which was $301.0{\pm}6.1\;{\mu}m/day$ at the dose of 100 mg/kg and $283.8{\pm}1.25\;{\mu}m/day$ (p < 0.001)at the dose of 10 mg/kg of HT005, compared to control group by the tetracycline fluorescent labeling method. HT005 showed a significant chondrocyte length on growth plate which was measured $797.19{\pm}3.31\;{\mu}m$ (p < 0.001) at the dose of 100 mg/kg and $720.14{\pm}2.19$ (p < 0.001) ${\mu}m$ at the dose of 10 mg/kg compared to the control group by cresyl-violet staining method. Both the number and intensity of BMP-2 and IGF-1 positive cells were increased in the hypertrophic zone of growth plate. There was a significant correlation between BMP-2 and IGF-1 expression and heights of chondrocytes in growth plate. Conclusions : Treatment of HT005 on Sprague-Dawley rats markedly increased the longitudinal bone growth. Therefore, HT005 may be an alternative herbal source to growth hormone as it promotes bone growth in children afflicted by growth retardation.

• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.3.1-3.11
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• 2018

This study aimed to verify the effects of estrogen on the onset and development of adolescent idiopathic scoliosis and the mechanisms associated with these effects by constructing a pubescent bipedal rat model. Experiments were conducted to investigate whether scoliosis progression was prevented by a Triptorelin treatment. One hundred twenty bipedal rats were divided into female, OVX (ovariectomy), OVX + E2, Triptorelin, sham, and male groups. According to a spinal radiographic analysis, the scoliosis rates and curve severity of the female and OVX + E2 groups were higher than those in the OVX, Triptorelin, and male groups. The measurements obtained from the sagittal plane of thoracic vertebrae CT confirmed a relatively slower growth of the anterior elements and a faster growth of the posterior elements between T11 and T13 in the female and OVX + E2 groups than in the OVX and Triptorelin groups. Histomorphometry and immunohistochemistry revealed a significantly longer hypertrophic zone of the vertebral cartilage growth plates that expressed more type X collagen and less type II collagen in the OVX and Triptorelin groups than in the female and OVX + E2 groups. Ki67 immunostaining confirmed an increase in the proliferation of vertebral growth plate chondrocytes in the OVX group compared with the female and OVX + E2 groups. In conclusion, estrogen obviously increased the incidence of scoliosis and curve severity in pubescent bipedal rats. The underlying mechanism may be a loss of coupling of the endochondral ossification between the anterior and posterior columns. Triptorelin decreased the incidence of scoliosis and curve magnitudes in bipedal female rats.