• Macromolecular Research
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• v.10 no.3
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• pp.158-167
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• 2002

In order to endow with new bioactive functionality from small intestine submucosa (SIS) powder as natural source to poly (L-lactide) (PLA) and poly (lactide-co-glycolide) (PLGA) synthetic biodegradable polymer, porous SIS/PLA and SIS/PLGA as natural/synthetic composite scaffolds were prepared by means of the solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. A uniform distribution of good interconnected pores from the surface to core region was observed the pore size of 40~500 ${\mu}{\textrm}{m}$ independent with SIS amount using the solvent casting/salt leaching method. Porosities, specific pore areas as well as pore size distribution also were almost same. After the fabrication of SIS/PLA hybrid scaffolds, the wetting properties was greatly enhanced resulting in more uniform cell seeding and distribution. Five groups as PGA non-woven mesh without glutaraldehyde (GA) treatment, PLA scaffold without or with GA treatment, and SIS/PLA (Code No.3 ; 1 : 12 of salt content, (0.4 : 1 of SIS content, and 144 ${\mu}{\textrm}{m}$ of median pore size) without or with GA treatment were implanted into the back of nude mouse to observe the effect of SIS on the induction of cells proliferation by hematoxylin and eosin, and von Kossa staining for 8 weeks. It was observed that the effect of SIS/PLA scaffolds with GA treatment on bone induction are stronger than PLA scaffolds, that is to say, in the order of PLA/SIS scaffolds with GA treatment > PLA/SIS scaffolds without GA treatment > PGA nonwoven > PLA scaffolds only with GA treatment = PLA scaffolds only without GA treatment for the osteoinduction activity. The possible explanations are (1) many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation, (2) the exposure of SIS to GA resulted in significantly calcification, and (3) peri-implant fibrosis due to covalent bonding between collagen molecule by crosslinking reaction. In conclusion, it seems that SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area.

• The Korean Journal of Zoology
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• v.12 no.4
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• pp.114-122
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• 1969

Electron microscopic examination of the liver and heart tissues of methylene blue-treated rats before gamma-irradiation was observed in this study. 1. It was observed severe alteration and degeneration of organelles: accumulation of glycogen particles, severe swollen mitochondria, and broken endoplasmic reticulum in liver tissue of saline-treated rat(control) opposed by emthylene blue-treated rat at 64 and 212 hours following gamma-irradiation. 2. Heart muscles of both methylene blue-treated and saline-treated rats showed no significant alterations, but it was observed that slightly elongated mitochondria with broken cristae and some of vacuoles as well as increased glycogen particles in sarcoplasmic reticulum at 212 hours following gamma-irradiation. 3. It may be considered that methylene blue greatly reduces the sensitivities of rats to gamma-irradiation.

• Clean Technology
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• v.21 no.4
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• pp.224-228
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• 2015

Phospholipase D (PLD) was immobilized on a submicro-porous membrane through covalent immobilization. The immobilization was conducted on the porous membrane surface with the treatment of polyethyleneimine, glutaraldehyde, and the anhydrase, in sequence. The immobilization was confirmed using X-ray photon spectrometer. The pH values of phosphatidylcholine (PC) dispersion solution with buffer were monitored with respect to time to calculate the catalytic activities of PC for free and immobilized PLD. The catalytic rate constant values for free PLD, immobilized PLD on polystyrene nanoparticles, and immobilized PLD on a porous cellulose acetate membrane were 0.75, 0.64, and 0.52 s^-1, respectively. Reusability was studied up to 10 cycles of PC hydrolysis. The activity for the PLD immobilized on the membrane was kept to 95% after 10 cycles, and comparable to the PLD on the nanoparticles. The stabilities for heat and storage were also investigated for the three cases. The results suggested that the PLD immobilized on the membrane had the least loss rate of the activity compared to the others. From these studies, the porous membrane was feasible as a carrier for the PLD immobilization in the production of phosphatidic acid.

• Restorative Dentistry and Endodontics
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• v.13 no.2
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• pp.283-294
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• 1988

The purpose of this study was to investigate the characteristic features of the cells and tissues of the chronic periapical lesions using light microscope and electron microscope. Fifteen dental periapical lesions were obtained from the patients undergoing periapical surgery. Each specimen was divided into two parts along the tooth axis. One part was routinely processed for histopathologic examinations. 12 periapical lesions were diagnosed as granuloma and 3 periapical specimens as periapical cyst. The other part was fixed in 2.5% glutaraldehyde in 0.1M sodium cacodylate buffer at pH 7.4 and 1% osmic acid in same buffer. They were embedded in Epon 812. The semithin sections were used for the orientation of the lesions and the ultrathin sections were stained conventionally and examined with AEI Corynth 500 electron microscope. The results were as follows. 1. PMN and macrophages, which were dominant cell type, were scattered in small or large numbers throughout the central destructive area of granuloma. In the granulomatous area, plasma cells and lymphoytes were found in significant number and a lot of new capillary formation were revealed. Clefts caused by cholesterol were often seen in the connective tissue. Occasionally foam cells became collected in groups and epithelial proliferation were present. 2. In both granuloma and cyst, some plasma cells contained narrow cisternae of granular endoplasmic reticulum of which was tightly packed with electron dense materials, and other cells exhibited dilated profiles of granular endoplasmic reticulum. 3. In the area where plasma cells and lymphocytes were collected in groups, lymphocytes with well developed nucleolus and profuse cytoplasm were found and differentiating plasma cells were also present. 4. In the epithelial strands of the granulomatous area, epithelial cells contained enlarged endoplasmic reticulum, tonofilaments and ribosoms. Toward the intercellular space epithelial cells protruded a few microvilli. In the intercellular space, exudate-like electron dense materials, most of which was attached to the plasma membrane, appeared. 5. Some foam cells filled with numerous lipid droplets and others had lipid droplets and crystal-like structures. 6. Cyst epithelium consisted of bright cells and dark cells. The former had bright cytoplasm and small amounts of ribosoms, and the latter dark cytoplasm, many ribosoms, mitochondria and elongated microvilli. 7. Epithelial cells near the cyst lumen protruded a lot of long microvilli toward intercellular space and cyst lumen.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.77-86
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• 1998

The uptake of glucose for metabolism and growth is essential to most animal cells and is mediated by glucose-transporter (GLUT) proteins. The aim of this study was to determine which class of glucose transporter molecules was responsible for uptake of glucose in the mouse early embryo and at which stage the corresponding genes were expressed. In addition, co-culture system with vero cell was used to investigate the effect of the system on GLUT expression. Two-cell stage embryos were collected from the superovulated ICR female and divided into 3 groups. As a control, embryos were cultured in 0.4% BSA-T6 medium which includes glucose. For the experimental groups, embryos were cultured in either co-culture system with vero cells or glucose-free T6 medium supplemented with 0.4% BSA and pyruvate as an energy substrate. 2-cell to blastocyst stage embryos in those groups were respectively collected into microtubes (50 embryos/tube). Total RNA was extracted and RT-PCR was performed. The products were analysed after staining ethidium bromide by 2% agarose gel electrophoresis. Blastocysts were collected from each group at l20hr after hCG injection. They were fixed in 2.5% glutaraldehyde, stained with hoechst, and mounted for observation. In control, GLUT1 was expressed from 4-cell to blastocyst. GLUT2 and GLUT3 were expressed in morula and blastocyst. GLUT4 was expressed in all stages. When embryos were cultured in glucose-free medium, no significant difference was shown in the expression of GLUT1, 2 and 3, compared to control. However GLUT4 was not expressed until morular stage. When embryos were co-cultured with vero cell, there was no significant difference in the expression of GLUT1, 2, 3 and 4 compared to control. To determine cell growth of embryos, the average cell number of blastocyst was counted. The cell number of co-culture ($93.8{\pm}3.1$, n=35) is significantly higher than that of control and glucose-free group ($76.6{\pm}3.8$, n=35 and $68.2{\pm}4.3$, n=30). This study shows that the GLUT genes are expressed differently according to embryo stage. GLUTs were detectable throughout mouse preimplantation development in control and co-culture groups. However, GLUT4 was not detected from 2- to 8-cell stage but detected from morula stage in glucose-free medium, suggested that GLUT genes are expressed autocrinally in the embryo regardless of the presence of glucose as an energy substrate. In addition, co-culture system can increase the cell count of blastocyst but not improve the expression of GLUT. In conclusion, expression of GLUT is dependent on embryo stage in preimplantation embryo development.

• Journal of Periodontal and Implant Science
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• v.40 no.5
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• pp.232-238
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• 2010

Purpose: To prolong the degradation time of collagen membranes, various cross-linking techniques have been developed. For cross-linking, chemicals such as formaldehyde and glutaraldehyde are added to collagen membranes, but these chemicals could adversely affect surrounding tissues. The aim of this study is to evaluate the ability of porous non-chemical cross-linking porcine-derived collagen nanofibrous membrane to enhance bone and associated tissue regeneration in one-wall intrabony defects in beagle dogs. Methods: The second and third mandibular premolars and the first molars of 2 adult beagles were extracted bilaterally and the extraction sites were allowed to heal for 10 weeks. One-wall intrabony defects were prepared bilaterally on the mesial and distal side of the fourth mandibular premolars. Among eight defects, four defects were not covered with membrane as controls and the other four defects were covered with membrane as the experimental group. The animals were sacrificed 10 weeks after surgery. Results: Wound healing was generally uneventful. For all parameters evaluating bone regeneration, the experimental group showed significantly superior results compared to the control. In new bone height (NBh), the experimental group exhibited a greater mean value than the control ($3.04{\pm}0.23\;mm/1.57{\pm}0.59$, P=0.003). Also, in new bone area (NBa) and new bone volume (NBv), the experimental group showed superior results compared to the control (NBa, $34.48{\pm}10.21%$ vs. $5.09{\pm}5.76%$, P=0.014; and NBv, $28.04{\pm}12.96$ vs. $1.55{\pm}0.57$, P=0.041). On the other hand, for parameters evaluating periodontal tissue regeneration, including junctional epithelium migration and new cementum height, there were no statistically significant differences between two groups. Conclusions: Within the limitations of this study, this collagen membrane enhanced bone regeneration at one-wall intrabony defects. On the other hand, no influence of this membrane on periodontal tissue regeneration could be ascertained in this study.

• Applied Microscopy
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• v.15 no.2
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• pp.111-129
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• 1985

The morphology and histology of the gastrointestinal mucosa of the mole, Talpa micrura coreana (Thomas), were studied using light and scanning electron microscopes. Tissue specimens were taken from body and pyloric portions of the stomach, and from the initial, proximal, middle, distal and terminal portions of the intestine. For light microscopy, tissue blocks were fixed in 10% buffered neutral formalin, embedded in paraffin wax, and sectioned at a thickness of $5{\mu}m$. These sections were stained with hematoxylin-eosin. For scanning electron microscopy, tissue blocks were fixed in 1% glutaraldehyde-1.5% paraformaldehyde, and postfixed in 1% osmium tetroxide, dehydrated in graded alcohol, transferred to isoamylacetate and dried by the critical point drier(Polaron E 3000). Subsequently, specimens were coated with gold and observed with a JSM-35C scanning electron microscope. The results were as follows: The mucous membrane of the body portion of the stomach had numerous irregular folds and the pyloric mucosa formed the strawberry-shaped folds, and general histological structures of each portion were similar to those of man. The intestine could not be differentiated macroscopically and microscopically into small and large intestines. There was no cecum, appendix, taenia coli, haustra coli or appendices epiploicae. In the initial portion (4 mm long), conical or tongue-shaped villi with the height of $143.3{\pm}10.7{\mu}m$ were present, and large mucous glands were seen in the submucosa. In the proximal, middle and distal portions, wavy folds composed of the epithelium and lamina propria were densely and transversely arranged, and their heights were $440.4{\pm}45.5{\mu}m,\;454.4{\pm}19.9{\mu}m\;and\;205.2{\pm}33.5{\mu}m$, respectively. The mucosa of the terminal portion (3 cm long) formed several longitudinal folds, and the intestinal glands were directly opened on the smooth surface of the folds. Aggregated lymphoid follicles were observed in the major portions of the intestine except the initial and terminal portions. There was no circular or semilunar fold throughout the intestine.

• Applied Microscopy
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• v.29 no.1
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• pp.57-66
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• 1999

The nervous tissue in the cerebral ganglion of Korean planaria was observed using electron microscope. The obtained results are as follows: A cerebral ganglion is composed of the nerve cells, neurosecretory cells, neuroglial cells and neuropils. The nerve cells are round or ovoidal-shaped cells (diameter, $5{\mu}m$), which has a large ellipsoidal nucleus containing the evenly developed heterochromatin. Their cytoplasms were found to be relatively simple, because of their undeveloped cell organelles. The neurosecretory cells are long and ellipsoid or spindle-shaped cells, where there were found a large ellipsoidal nucleus and cytoplasm filled with secretory granules (diameter, 60 nm). The neuroglial cells were seldom observed. They are spindle-shaped cells (size, $6\times0.8{\mu}m$), which were observed mainly among the nerve fibers. The neuropils are formed by the nerve fibers and nerve endings which are filled with mitochondria, neurotubules and secretory granules of four kinds (high electron dense granules of sizes 75 nm, 50 nm and 37 nm, and electron lucent granule of size 30 nm etc.). These granular vesicles are divided into single vesicle type and compound vesicle type in the nerve terminals, and neuronal synapses were observed to be the axo-dendritic and dendro-dendritic synapse type.

• Applied Microscopy
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• v.28 no.4
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• pp.425-434
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• 1998

This study was designed to investigate the microglial reactions to the neurodegenerative changes in the cat retina. All experiments were performed using adult cats of both sex, weighing $2,500g\sim3,500g$. 5,7-DHT $(100{\mu}g)$ dissolved in 0.1% ascorbic acid was injected into the vitreous body. All injections were performed in one-side eye; the other side served as the control, which was injected only with 0.1% ascorbic acid. Cats were sacrificed at 1, 3, 7, 14 and 21 days after intravitreal injection of 5,7-DHT For light microscopy, retinae were fixed with 4% paraformaldehyde and processed using NDPase histochemistry. Same retinae were fixed with 1% para(formaldehyde-2.5% glutaraldehyde and processed for electron microscopy. NDPase-positive microglial cells were mainly distributed in the inner plexiform layer of the retina, and characterized by a small somata with a few slender processes, which were also extended in the ganglion cell layer (GCL) and inner nuclear layer (INL). The intensity of the microglia stained for NDPase was abruptly increased at 7 day as compared with that of the control, and thereafter continuously sustained until 21 day, the last experimental group in this study. Under the electron microscopical observation, microglial cells in the control group exhibited elongate nucleus with perinuclear chromatin condensation, and the perikaryon was scanty. However, a few hypertrophic glial cells were frequently found at 3 days after the drug injection. By 7 day, most microglial cells directed toward the degenerated neurons in the GCL, and the number of microglial cells was slightly increased as compared with the former group. At the 14 day, most microglial cells wrapped the degenerated cells in the GCL, and a few cells showed phagocytotic features. By 21 day, most microglial cells were engaged in phagocytotic activity, and their cytoplasm was filled with the phagorytosed material. Based on the results, 5,7-DHT may act as a specific neurotoxin to the cat retina, and microglial reactions to the neuronal death are already induced in early experimental stage. These results indicate that the microglial cells in the cat retina show characteristic features as a protective effect of neural tissue.

• Applied Microscopy
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• v.34 no.2
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• pp.145-157
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• 2004

The aim of the present study was to examine in detail, both at light and electron microscopical levels, the morphological variations in ameloblast of the fetal rat incisor enamel organ. Rats were started on distilled water at the beginning of pregnancy. The pups were sacrificed 11 days after delivery and animals were perfused intravascularly with glutaraldehyde and the incisors were removed. To examine on the ultrastructure of the ameloblast, the study employed primary light microscopy but electron microscopy was used to clarify some of the light microscopic finding. Longitudinal sections through the incisors of the rat show a continuous layer of ameloblasts on the labial surface of the tooth. This layer contains the entire sequence of developmental stages in enamel production. The ameloblast layer was divided into three main zones: 1) Presecretory zone, region of ameloblasts facing pulp. 2) Secretory zone, region of inner and outer enamel secretion. 3) Maturation zone, region of reduced ameloblasts. In particularly, the present study has shown that two distinctively different types of ameloblasts appear in the enamel organ during enamel maturation in the rat incisor. These two types have been designated ruffle-ended ameloblasts (rAB) and smooth-ended ameloblasts (sAB). The fluoride produces marked alteration in the fine structure of ameloblast from teeth of young rats, such as large confluent distensions of the endoplasmic reticulum and swelling of isolated mitochondria. This experimental data suggested that exposure prolonged of animal to high level of fluoride appears to induce a few dramatic changes in the normal appositional growth and initial mineralization of enamel created during amelogenesis.