• Applied Microscopy
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• v.28 no.3
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• pp.399-414
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• 1998

Glandular trichomes present on the leaf surface of Drosera capensis were examined using transmission electron microscopy. A large number of stalked glands exist on the adaxial surfaces of the leaf blade. The secretory head is composed of two layers of secretory cells, one layer of middle cells, and the inner tracheids. The secretory cells contain rough endoplasmic reticulum, mitochondria, plastids, Golgi apparatus, and vacuoles. The secretory cells show prominent cell wall ingrowth, and thick cuticle restricted on the subcuticular wall. Frequently, the cuticle has some pores, canal-like structures, showing electron -dense granules being penetrated through them. Ultrastructural localization using diaminobenzidine showed the electron-dense deposits in the vacuole. No peroxidase activity was seen in the cell wall and cytolasm. The activity of peroxidase (POX) isozymes in Drosera which isoelectric point (pI) is 3.6 and some anionic POX isozymes which pIs are laid between 3.6 and 4.6 were especially increased according to the development and the formation of glandular trichomes. Also, the activity of some POX isozymes which isoelectric points are laid between 4.6 and 5.1 were increased in the regions of leaves which has trichomes.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.05
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• pp.9-12
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• 1990

He impregnated a highly porous, knitted polyester (Dacron) graft with a biodegradable nonproteinaceous material, algin. This new vascular graft is blood tight but still retains high porosity in the body. It does not need to be preclotted with blood before implantation and has good tissue ingrowth and biological healing properties due to the high porosity. The algin impregnated graft was investigated by "in vitro" examinations in this study. It was characterized by ESCA analysis, SEM observation, and measurements of water permeability, algin coating weight, mechanical properties and whole blood clotting time. The water permeability of the graft was reduced more than 99% by the algin impregnation treatment without changing any mechanical properties. "In vivo" examinations of the algin impregnated vascular graft are on progress.

• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.251-261
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• 2013

A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.1
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• pp.24-31
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• 2005

Recently, Platelet rich plasma(PRP) is commonly used because it is now well known that platelets have many functions beyond that of simple hemostasis in aspect of containing autogenous source of several growth factors. It could be responsible for increasing cell mitosis, increasing collagen production, recruiting other cells to the site of injury, initiating vascular ingrowth, and inducing cell differentiation, enhancing bone formation capacity and easily handling to clinician. However, in spite of these clinical advantages, still the theory behind the use of PRP is compelling. This study was to determine preparation techniques used to increase the concentration of platelets and growth factors are all crucial steps in early wound healing of bone graft which may lead to a more rapid and denser bone regenerate. 200 volunteers were sampled and PRP were prepared according to each evaluation item in this study. Higher concentration of platelets have been gained in double centrifugation. 2000 and 2500 rpm showed proper concentration of platelets at first centrifugation and 5000 rpm in second. Timing for 2 minutes was showed good concentration of platelets in high and low centrifugation speed. It was better concentration of platelets in 20 or 30 ml volume during centrifugation. In histomorphologic findings, degrnulated and high concentraion of platelets were found in low centrifugation speed.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.89-94
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• 2003

The use of titanium alloys as biomaterials is increasing due to their superior biocompatibility and enhanced corrosion resistance compared to conventional stainless steels and cobalt-based alloys. Ti-6Al-4V ($\alpha+\beta$type) alloy instead of pure titanium ($\alpha$type) is being widely used as biomaterials has some characteristics such as high fatigue strength, tensile strength and corrosion resistance. It also has similar characteristics to Ti in inducing bony ingrowth. But it has been reported recently that the vanadium element expresses cytotoxicity and carcinogenicity and the aluminium element is related with dementia of Alzheimer type and neurotoxicity. In order to overcome their detrimental effects, $\beta$-phase stabilizer Nb was chosen in the present study. CP-Ti(ASTM grade 2), Ti-3wt.%Nb($\alpha$type), Ti-20wt.%Nb ($\alpha+\beta$type) and Ti-40 wt.%Nb($\beta$type) alloys were melted by vacuum arc furnace. Biocompatibility of Ti-Nb alloys was evaluated by cytotoxicity test. The results can be summarized as follows: 1. For the cytotoxicity test, Ti-Nb alloys showed excellent biocompatibility compared to CP-Ti(ASTM grade 2), 316L STS and Co-Cr alloys.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.197-203
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• 2000

Maxillary defect may be induced by trauma, inflammation, cyst, tumor and surgical procedure. In case of limited wall defect, free bone graft has been preferred. But it has some problems such as postoperative bone resorption and soft tissue inclusion to recipient site. And we can not use free bone in the case who has inflammation in the donor site. So we used the micro-titanium mesh as reconstructive material for the maxillary wall defect. We had operated 8 patients who were diagnosed as maxillary partial defects from June 1997 to September 1998 in the Chin-Hae military hospital. They were 1 case of antral wall defect, 1 case of palatal wall defect, 5 cases of infra-orbital wall defects and 1 case of oroantral fistula case. As a result, the micro-titanium mesh has shown the morphological stability and biocompatibility and it could be used in case who has infection. And mesh structure could prevent soft tissue ingrowth to bony defect area. Thus it can be used to the case of maxillary partial defect successfully.

• Applied Microscopy
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• v.43 no.4
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• pp.140-145
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• 2013

Structural aspects of highly reduced vegetative organs in the aquatic Spirodela polyrhiza were examined using scanning and transmission electron microscopy. The study focused mainly on young and mature fronds with turions and their cellular features were compared. Mature fronds were composed of thin-walled chlorenchyma with highly vacuolated cells; most of which were frequently occupied by either tanniferous deposits or various crystals. Fronds of photoautotrophic offspring were produced from the meristematic region of the reproductive pockets within mother fronds, where they remained until separation. Moderate degrees of wall ingrowth and plasmalemma proliferation were detected briefly in the epidermis of daughter fronds during early development. Vascular tissues were generally much reduced, but air chambers were well-established in fronds. Chloroplasts having grana with several thylakoids were distributed throughout the plant, but starch grains were encountered frequently in the mesophyll chloroplasts of younger fronds and initial stage of the turion. Their cytoplasm was dense with small vacuoles in most cases. Further, big starch grains, up to several microns, occupying most of the plastid volume were formed in the turion prior to sink for overwintering. Plasmodesmata were numerous in the examined tissues, except mature turions, suggesting a symplastic pathway of the metabolites within body.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.510-518
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• 2005

In this study, we investigated whether PLGA microspheres in combination with hyaluronic acid (HA) gel have appropriate properties as a bulking agent for urologic injection therapies and whether the implantation of PLGA microspheres and HA gel induces angiogenesis in the newly formed tissues. In order to investigate whether this bulking agent is injectable, this material was injected through 24-gauge needles into the subcutaneous dorsum of the mouse. The bulking agent was easily injected without needle obstruction. Histological analyses of the hybrid tissues at 2 weeks showed that host cells at the surrounding tissues migrated into the spaces between the implanted PLGA microspheres and formed tissue-like structures. An inflammatory response to the implants was mild at 2 weeks and diminished at 8 weeks. Importantly, extensive ingrowth of blood vessels was observed in the hybrid tissues formed by the injection of PLGA microspheres and HA, whereas blood vessels rarely formed in the hybrid tissues formed by the injection of PLGA microspheres only. The implant volume was conserved for almost the entire implantation period. Histological analyses of the distant organs of the bulking agent-implanted animals, such as the lungs, liver, heart, brain, kidney, and spleen, showed no evidence of the injected microsphere migration. These results show that PLGA microspheres in combination with HA possess the appropriate characteristics for a bulking agent for urologic injection therapies and induce extensive blood vessel formation in the hybrid tissues.

• Journal of Biomedical Engineering Research
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• v.12 no.3
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• pp.165-170
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• 1991

Many experiments about endothelial cell seeding on artificial vessels were studied and conducted For this one or a combination of the extramatrix was used for the underlying matrix. But we used the whole ECM(extracellular matrix) that made excreated from flbroblasl. In thls study, we obtained human adult omental microvascular endothelium by collagenase digestion and used polyurthane sheets in order to make a new artificial vessel material. We cultured fibroblast on the polyurethane and gelatin - coated polyurethane. After confluent ingrowth we treated the polyure thane with triton in order to destroy the cytoskeleton and nucleus. We observed the preformed extra cellular matrix on the ployurethane and cultured the isolated microvascular endothelium. We also ok served the growth of microvascular endothelium on the polyurethane and gelatin. We conclude that the use of the whole ECM is promising fair as a new underying substrate for endothelial cell seeding on artificial vessels.

• Journal of Biomedical Engineering Research
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• v.12 no.3
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• pp.157-164
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• 1991

Microvel $^{\textregistered}$ double velour graft impregnated with a biodegradable algin was studied as a new vatscular graft. It is impervious to blood but still retains high porosity. This graft does not require preclotting during implantation and has good tissue ingrowth and biological healing properties. Two vascular grafts impregnated with algin (6mm in diameter) were implanted in the aorta of mongrel dogs without preclotting. Two identical grafts were preclctted and served as controls. The grafts were harvested 2 and 4 months postoperatively, and the healing pattern was examined by a light microscope after hemRtoxylineosin staining. It was observed that endothelial cells were incompletely covered on both algin-impregnated and control grafts after 2 month Implantation, while they were fully covered on both grafts after 4 month. There were no significant differences in subendothelial granulation tissue organization and fibrinoid material absorption between the algin-impregnated and control grafts. The algin-impregnated graft did not show any harmful effect on the healing and thus can be a new promising graft which is not necessary preclotting during the implantation.