• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.991-992
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.248-251
• /
• 2005

To investigate the degeneration process in the intervertebral disc, a three dimensional (3D) poroelastic finite-element (FE) model was developed. Disc was modeled as two different regions, such as annulus modeled with fiber reinforced 20 node poroelastic ground matrix and nucleus having large porosity. Excess Von Mises stress in the disc element assumed to be a possible source of degeneration under compressive loading condition. Recursive calculation was continued until the desired convergence was attained by changing the permeability and porosity of those elements, which could be predicted from the previous iteration. The degenerated disc model showed that relatively small compressive stresses were generated in the nucleus elements compared to normal disc. Its distribution along the sagittal plane was matched well with a previously reported experimental result. Contrasts to this result, pore pressures in the nucleus were higher than those in the normal disc. Total stress indicated similar values for two different models. This new approach using poroelastic modeling could provide the explanation of the interaction between fluid and solid matrix in the disc during the degeneration process.

• Journal of International Academy of Physical Therapy Research
• /
• v.8 no.1
• /
• pp.1071-1076
• /
• 2017

The purpose of this study was to determine if a gentle form of manual lumbar traction could reduce painful lumbar motions associated with lumbar disc degeneration (LDD). This clinical trial incorporated 134 participants with painful active lumbar motion. Participants were randomly assigned to an experimental treatment or sham group. 67 participants received sidelying manual lumbar traction while the other 67 participants received a sham treatment. Pre and post treatment NPRS values for the painful active lumbar motion were recorded for each group. There was a statistically significant improvement (P=0.00) for decreased pain intensity during active lumbar motion in the experimental group as compared to the sham treatment group. The average percent decrease in numeric pain rating scale (NPRS) values was 52.1% for the experimental treatment group and 8.1% for the sham group. The results of the study suggest that side-lying manual lumbar traction can improve painful lumbar motion in patients with LDD.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.10 no.1
• /
• pp.35-45
• /
• 1983

This study was undertaken to evaluate the pulpal responses to the intermediate restorative materials such as Zinc phosphate cement, Polycarboxylate cement, IRM (zinc oxide eugenol cement), Dycal, Life, Cresatin, and Fluoride in caivties which were cut with high speed instrument. 5 dogs were used as experimental animals and devided into 8 groups. The intervals of observaobservation ranged 3 days, 1, 3, 4, 8 weeks after experiment respectively. The specimens were fixed with 10% formalin and decalcified in 5% nitric acid. All slides were stained with hemtoxylin-eosin and examined histopathologically. The results were as follows: 1. In control group, severe vacuolar degeneration and atrophy of odontoblasts were seen in 3 days, hemorrhage and congestion continued until 8 weeks. Necrosis of odontoblastic layer was seen in zinc phosphate cement group and polycarboxylate cement group. 2. In dycal group, vacuolar degeneration and atrophy of odontoblast were not seen. but in Life group, these were seen in 3 days and partially continued until 3 weeks. In 4 weeks, regeneration of odontoblast was occured. 3. In Crcsatin group, there was no pathosis except odontoblastic displacement. In Fluoride group, vacuolar degeneration of odontoblast was seen and soon disappeared. As compared with control group, pathological change of the pulp tissue in experimental group were decreased after amalgam restoration.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.18 no.1
• /
• pp.31-45
• /
• 1988

The author studied the histopathologic changes according to a single or a split dose and the time after irradiation on the acinar cells of rat parotid gland. 99 Sprague Dawley rats, weighing about l20gm, were divided into control and 3 experimental groups. In experimental groups, GroupⅠ and Ⅱ were delivered a single dose of l5Gy, 18Gy and Group Ⅲ and Ⅳ were delivered two equal split doses of 9Gy, 10.5Gy for a 4 hours interval, respectively. The experimental groups were delivered by a cobalt-60 teletherapy unit with a dose rate of 222cGy/min, source-skin distance of 50㎝, depth of l㎝ and a field size of l2×5㎝. The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and examined by light and electron microscopy. The results were as follows: 1. As the radiation dose increased and the acinar cells delivered a single dose exposure were more damaged, and the change of acinar cells appeared faster than those of a split dose exposure. 2. The histopathologic change of acinar cells appeared at 1 hour after irradiation. The recovery from damaged acinar cells appeared at 1 day after irradiation and there was a tendency that the recovery from damage of a split dose exposure was somewhat later than that of a single dose exposure. 3. Light microscope showed atrophic change of acinar cells and nucleus, degeneration and vesicle formation of cytoplasm, widening of intercellular space and interlobular space. 4. Electron microscope showed loss of nuclear membrane, degeneration of nucleus and nucleoli, clumping of cytoplasm, widening and degeneration of rough endoplasmic reticulum, loss of cristae of mitochondria, lysosome, autophagosome and lipid droplet. 5. Electron microscopically, the change of rough endoplasmic reticulum was the most prominent and this appeared at 1 hour after irradiation as early changes of acinar cells. The nuclear change appeared at 2 hours after irradiation and the loss of cristae of mitochondria was observed at 2 hours after irradiation in all experimental groups.

• The Korean Journal of Malacology
• /
• v.32 no.1
• /
• pp.9-15
• /
• 2016

This study was conducted to find out biological response of the oyster Crassostrea gigas exposed to lead (Pb). Experimental period was four weeks. Experimental groups were composed of one control condition and three lead exposure conditions (0.20, 0.40 and 0.80 mg/L). The results of the study confirmed that lead induces reduction of survival rate and oxygen consumption rate and degeneration of organ structure of the bivalve. Oxygen consumption rate was observed exposure groups lower than control decline by 15%-55%. Histological analysis of organ system illustrated expansion of hemolymph sinus, degeneration of epithelial layer and connective tissue layer of the mantle. Also, epithelial degeneration and disappearance of cilia band are recognized in the gill filament and it was observed disruption of epithelial layer and degeneration of basophilic cell and epithelial cell in the digestive tubules.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.8 no.1
• /
• pp.11-15
• /
• 1978

The author observed the effect of x-ray irradiation on the development of the mandible in the fetuses and growing albino rats. The fetuses were irradiated on the 7½th day of gestation, 100, 200, 300, and 400 rads of x-ray respectively. The experimental animals were sacrificed on the 18½th day of gestation, and first week, second week and third week after parturition. The results were as follows; 1. The mandible of the 18½th day fetuses showed irregular bone trabeoulae, osteoclasts and osteocyte degeneration on the 300 and 400 rads x-ray irradiated fetuses. 2. In the mandible of the first week rats, there was marked osteocyte degeneration and a lot of osteoclast. 3. In the mandible of the 2nd and 3rd week rats bone remodeling was evident. The 3rd week rats also showed alteration of blood vessel wall.

• The Journal of the Korean dental association
• /
• v.15 no.7
• /
• pp.517-519
• /
• 1977

The author studied the effects of cyclophosphamide to the Dental pulps of Rabbits. Eighteen rabbits were used. The experimental rabbits were given an intramuscular injection of cyclophosphamide 50mg. per 1.5Kg. of body weight. In order to investigate effects of cyclophosphamide to the pulps of rabbits the control and experimental rabbits were sacrificed, on 1,3,5,7,10, and 14 days after injection of cyclophosphamide and made preparations for histopathologic findings. The results were as fallows. 1. In the early stage after injection of cyclophosphamide, retrcgrade degeneration of pulps such as infiltration of inflammatory cells, vacuolization, hyaline degeneration and reticular tissue atrophy in pulps were revealed. 2. The pulps were recovered from 10 to 14 days after injection of cyclophosphamide.

• The Journal of the Korean dental association
• /
• v.23 no.9 s.196
• /
• pp.783-801
• /
• 1985

• Clinics in Shoulder and Elbow
• /
• v.25 no.1
• /
• pp.5-14
• /
• 2022

Background: The purpose of this study was to verify the effect of protocatechuic acid (PCA) on tendon healing and fatty degeneration in a chronic rotator cuff model. Methods: Twenty-eight Sprague-Dawley male rats were randomly allocated into two groups: Saline+repair (SR) and PCA+repair (PR). The right shoulder was used for experimental interventions, and the left served as a control. PCA (30 mg/kg/day) was administered intraperitoneally at the site of infraspinatus tendon detachment in rats in the PR group, and the same volume of saline was administered to the same site in the SR group. The torn tendon was repaired 4 weeks after infraspinatus detachment. Four weeks after repair, hematoxylin and eosin (H&E), S100, and CD68 stains were performed to evaluate the degree of fatty degeneration and H&E and Masson trichrome stains were performed to assess tendon healing. Superoxide dismutase (SOD) was measured to test the efficacy of PCA as an antioxidant. Results: Results from histological evaluation indicated that SOD and CD68 levels at the musculotendinous region and collagen fiber parallel to the orientation at the tendon-to-bone junction were not significantly different between the SR and PR groups. The mean load-to-failure of the PR group (20.32±9.37 N) was higher than that of the SR group (16.44±6.90 N), although this difference was not statistically significant (p=0.395). The SOD activity in the operative side infraspinatus muscle of the PR group was higher than that of the SR group, but the difference was not statistically significant (p=0.053). Conclusions: The use of PCA could improve tendon healing and decrease fatty degeneration after rotator cuff repair.