• Applied Microscopy
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• 제27권2호
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• pp.189-196
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• 1997

The ultrastrucures of Xenopus otic vesicle from normal embryo (st. 43) and induced otic vesicle from animal cap assay with Activin A were compared. Activin A was applied to the presumptive ectoderm at various concentrations for three days at $20^{\circ}C$. The results were almost identical to the reference studies, but it was found that the otic vesicle was induced at the concentration of 10 ng/ml in to)v rate. This otic vesicle may be secondarily induced by the neural tissue showed commonly at the concentration of 10 ng/ml. Otoliths were observed as three or four-axis crystaline bodies in the lumen of otic vesicle. In electron micrograph of the normal embryo, two kinds of microvilli were observed on the apical position of hair cells. One was small and common, the other was large-sized and sparsely distributed. In both cell of otic vesicle, mitochondria, golgi apparatus and multivesicular body were rich, so, they showed a lot of similarities in ultrastructure. However, the otolith was not found and microvilli were overexpressed in the otic vesicle induced by Activin A.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2001년도 전기 제11차 학술대회 논문집
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• pp.46-49
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• 2001

R. Philippinarum is dioecious and oviparous. In the early vitellogenic oocyte, the Golgi apparatus and mitochondria present in the perinuclear region are involved in the formation of lipid droplets and in lipid granule formation. In the late vitellogenic oocyte, the endoplasmic reticulum, mitochondria in the cytoplasm are involved in the formation of proteid yolk granules. At this time, exogenous lipid granular substance and glycogen particles in the germinal epithelium are passed into the ooplasm of oocyte through the microvilli of the vitelline envelope. Ripe oocytes are about 55-60 $\mu$ m in diameter. The spawning period was once a year between early June and early October, and the main spawning occurred between July and August when seawater temperature was approximately 20 C. The reproductive cycle of this species can be categorized into five successive stages: early active stage (February to March), late active stage (April to May), ripe stage (April to August), partially spawned stage (June to October), and spent/inactive stage (August to March). Gonad developmental phases by histological qualitative analysis showed similar results with those of quantitative image analysis.

• Applied Microscopy
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• 제22권1호
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• pp.15-32
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• 1992

This study was an attempt to investigate and compare the fine structure of small cells in the space of Disse of various animal livers. All animal livers contained small cells with or without lipid droplets and the one with lipid droplet seemed to be more developed and show an abundance of activity in function. The fine structure of the small cells observed in the nonmammals was similar to that of Ito cell in the mammal. The electron density of the small cells was similar to that of other cell types in the same animal liver. The cisternal dilation of rough endoplasmic reticulum and Golgi apparatus was more predominant in the mammalian Ito cells. In the nonmammalian, aquatic vertebrates, however, lysosomes and filaments are much more abundant in the Ito cell and its abundant cytoplasmic processes rich in filaments were usually extended between the parenchymal cells. The disparity in size of organelles and numbers of lipid droplets in the small cells showed a tendency similar to those of other cell types in the same animal. From these results, it is considered that the small cells in the space of Disse is a Ito cell and the Ito cell without lipid droplets differentiates into the one containing lipid droplets according to the characteristics of the different animals respectively, and that the Ito cells in the mammals are more active in metabolic function, while those in the nonmammalian aquatic vertebrates are abundant in support of parenchyme.

• 생명과학회지
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• 제8권4호
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• pp.449-456
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• 1998

태생 13일된 토끼의 발생기 신장에서 뇨세관과 사구체 세포들의 크기와 형태를 관찰하여 성숙한 토끼의 신장과 형태계측학적으로 비교한 결과 다음과 같은 결과를 얻었다. 1. 태생 13일의 발생기 뇨세관 단면적은 성숙한 토끼의 근위세관 단면적보다 훨씬 넓고 평균직격이 길었으며 내강이 거의 없었다. 뇨세관 상피세포의 솔모양 가장자리는 발달되지 않았고 핵 위쪽에 둥근 사립체가 발달되었으며 기저막부분에는 사립체가 적었다. 2. 발생기 사구체내에는 벽측세포, 족세포, 내피세포들로 구별되었으며 성숙한 토끼보다 내피세포와 벽측세포의 세포핵 단멱적이 훨씬 컸고 성숙한 토끼의 사구체에서는 족세포가 가장 컸으나 발생기에는 내피세포의 크기가 가장 컸다.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.744-757
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• 1995

Implantation of demineralized bone matrices was done into the amputated pulp in vivo and sequential reaction of the pulpal ectomesenchymal cells was observed. The bone matrices, obtained from cat long bone were crushed into below $700{\mu}m$, demineralized with 0.5N HCl and allografted into pulp of molar teeth. At seven days after implantation many undifferentiated mesenchymal cells aggregated near the matrices in the pulpal tissue. At fourteen days after implantation, the cells differentiated into preosteoblast-like cells which have secretory cell characteristics. At one or two months after implantation osteoid tissue was formed. The cells, which are located at the surface of the tissue, contained abundant dilated rough endoplasmic reticulum, Golgi apparatus and secretory granules in the cytoplasm. The matrix of the tissue has less collagen fibers than those in normal dentin. These results suggest that the interaction of pulpal mesenchymal cells with demineralized bone matrix can be a model which induces mineralization.

• Applied Microscopy
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• 제50권
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• pp.16.1-16.11
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• 2020

Silk is produced by a variety of insects, but only silk made by terrestrial arthropods has been examined in detail. To fill the gap, this study was designed to understand the silk spinning system of aquatic insect. The larvae of caddis flies, Hydatophylax nigrovittatus produce silk through a pair of labial silk glands and use raw silk to protect themselves in the aquatic environment. The result of this study clearly shows that although silk fibers are made under aquatic conditions, the cellular silk production system is quite similar to that of terrestrial arthropods. Typically, silk production in caddisworm has been achieved by two independent processes in the silk glands. This includes the synthesis of silk fibroin in the posterior region, the production of adhesive glycoproteins in the anterior region, which are ultimately accumulated into functional silk dope and converted to a silk ribbon coated with gluey substances. At the cellular level, each substance of fibroin and glycoprotein is specifically synthesized at different locations, and then transported from the rough ER to the Golgi apparatus as transport vesicles, respectively. Thereafter, the secretory vesicles gradually increase in size by vesicular fusion, forming larger secretory granules containing specific proteins. It was found that these granules eventually migrate to the apical membrane and are exocytosed into the lumen by a mechanism of merocrine secretion.

• Applied Microscopy
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• 제20권1호
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• pp.36-50
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• 1990

This experiment was performed to study the morphological responses of the enterochromaffin cells in the duodenal mucosa of rabbit following bile duct ligation. Adult male rabbits were divided into normal, sham operation and experimental groups. Bile duct ligation was performed under ether anesthesia and animals were sacrificed on the 1st, 3rd, 5th, 7th and 14th day after operation. Mucosal specimens from the duodenum were prefixed with 2.5% glutaraldehyde-1.5% paraformaldehyde(0.1M Millonig's phosphate buffer, pH 7.3), followed by postfixation with 1% osmium tetroxide(0.1M Millonig's phosphate buffer, pH 7.3), and embedded within araldite mixture. The sections were cut on a LKB-V ultratome, and observed under a JEM 100CX II electron miroscope. The results were as follow; 1. Irregularities of the nuclei of the enterochromaffin cells were noticed from the 1st day after bile duct ligation, and concentration of the chromatin in the nucleus was more frequently observed on the 7th and the 14th day. 2. The granular endoplasmic reticulum and Golgi complex of the enterochromaffin cell were more developed than those of the normal on the 1st day after bile duct ligation, but they showed poor organization from the 3rd day. 3. Amount of the microfilaments in the enterochromaffin cell was significantly increased from the 5th day after bile duct ligation and they were more frequently observed in the vicinity of the nucleus. 4. Vacuoles with various electron densities in the enterochromaffin cell were increased in number from the 3rd day after bile duct ligation. 5. Glycogen-like particles in the enterochromaffin cell were frequently observed on the 3rd and the 5th day after bile duct ligation. 6. In the early stage of the ligation of bile duct, in the enterochromaffin cells, well developed intracellular organelles, such as granular endoplasmic reticulum and Golgi apparatus were pronounced. But, in the later stage, the cells contained poor organelles, with the some structural sign of necrotic change.

• Applied Microscopy
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• 제19권1호
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• pp.27-33
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• 1989

Six cases of ovarian fibrous stromal neoplasm were studied clinically, light microscopically and ultrastructurally for the clinico-pathological evidences of hormone production. Of the six cases, two cases were fibroma, three cases were fibrothecoma, and one case was thecoma. Two cases of fibroma and one fibrothecoma were associated with clinical history of menstrual abnormality, however fat staining of the tumor was negative or weakly positive. Two cases of fibrothecoma and one thecoma were negative for the clinical history of hormone imbalance. Fat stain of those cases revealed positive in varying intensity. Ultrastructural examination of fibroma-thecoma group revealed dark and pale cells by their nuclear characteristics. The dark cells had indented nucleus and abundant cytoplasmic organelles of rough ER, Golgi apparatus and mitochondria. Intracytoplasmic cisternal spaces were seen in the dark cell cytoplasm and some lipid droplets were seen around the cisternae. Pale cells had pale swollen nucleus and fine chromatins. Their cytoplasm showed scanty amount of organelles. Fibroma-thecoma spectrum showed varying degree of population of dark cells, light cells and intervening collagenous stroma. Lipid droplet was structurally associated with intracytoplasmic cisterna and they were frequently seen in thecoma and two of the fibrothecoma. But clinical history of hormone imbalance was poorly related to the light microscopic morphology and ultrastructural organization.

• Applied Microscopy
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• 제14권2호
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• pp.29-37
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• 1984

난소절제한 흰쥐에서 $17{\beta}$-estradiol과 progesterone을 장기간 주사햐여 자궁상피의 형태적 변화를 전자현미경으로 관찰하였다. 난소절제 후 자궁상피는 막성구조물과 지방구 기타의 구조물을 포함하는 vacuole의 출현이 특이적으로 나타났다. 상피는 낮은 입방형이며 세포 유리면에 소수의 짧은 microvilli를 볼 수 있었다. Estradiol투여시 상피는 높은 윈주형을 나타내며, 분비계는 비교적 잘 발달되고, 세포 유리면에 소수의 긴 microvilli도 관찰되었다. Progesterone 처리시의 상피는 세포 첨단부에 다수의 vacuole과 핵하부에 다수의 지방구의 집적이 관찰되었다. 이상의 결과로 보아 자궁상피는 형태학적 및 기능적인 상태에서 estrogen과 Progesterone 양자에 의해 변화를 받으며 이들 호르몬은 상피세포에 대해 독특한 영향을 나타낸다고 생각된다.

• Applied Microscopy
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• 제30권3호
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• pp.311-319
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• 2000

대하 아가미의 형태와 미세구조를 광학현미경과 전자현미경으로 조사하였다. 대하는 수지형 아가미를 가진 다. 아가미는 출새관과 입새관을 구분하는 세로 격벽을 가진다. 각각의 새판은 전자밀도가 다른 다층구조의 큐터클로 싸여 있다. 새판 기저세포들은 편평형이며, 전자밀도가 높은 세포질을 가진다. 상피세포층은 단층으로 큰 핵을 가진 편평상피로 구성된다. 새판의 기둥구조는 세로방향의 미세소관들과 측면 membrane interdigitation을 가진다. AB-PAS음성 분비세포들은 다세포선의 형태이다. 활성화된 선에서 각 세포의 경계부는 뚜렷하지 않으며, 세포질에는 활면소포체, 미토콘드리아, 전자밀도가 낮으며 막을 가진 분비소포들과 granular rosettes를 가진다. 비 활성화된 선에서는 세포 경계가 뚜렷하며, 세포질에서는 전자밀도가 높은 다수의 작은 과립들이 산재한다. 그리고 alcian blue에 양성인 단세포 분비세포들은 세포질에 발달된 다수의 골지체와 조면소포체들을 함유한다.