• Molecules and Cells
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• 제42권2호
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• pp.113-122
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• 2019

Communications at the interface between the apical membrane of follicular cells and the follicular lumen are critical for the homeostasis of thyroid gland. Primary cilia at the apical membrane of thyroid follicular cells may sense follicular luminal environment and regulate follicular homeostasis, although their role in vivo remains to be determined. Here, mice devoid of primary cilia were generated by thyroid follicular epithelial cell-specific deletion of the gene encoding intraflagellar transport protein 88 (Ift88). Thyroid follicular cellspecific Ift88-deficient mice showed normal folliculogenesis and hormonogenesis; however, those older than 7 weeks showed irregularly dilated and destroyed follicles in the thyroid gland. With increasing age, follicular cells with malignant properties showing the characteristic nuclear features of human thyroid carcinomas formed papillary and solid proliferative nodules from degenerated thyroid follicles. Furthermore, malignant tumor cells manifested as tumor emboli in thyroid vessels. These findings suggest that loss-of-function of Ift88/primary cilia results in malignant transformation from degenerated thyroid follicles.

• Applied Microscopy
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• 제26권3호
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• pp.369-377
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• 1996

Ultrastructural changes of chloride cells in the gill from seawater-adapted killifish (Orizias latipes) were studied with a transmission electronmicroscope. Chloride cells contain many mitochondria and specifically developed tubular systems. Apical pits, formed by several neighboring chloride cells, were exposed to the environment. Degeneration and death of the chloride cells by apoptosis occurred more frequently than by necrosis. Apoptotic chloride cells shrank, became to apoptotic bodies, and eventually were phagocytosed and digested by the microphages around them. We conclude that apoptosis plays an important role in increased cellular turnover of chloride cells for the osmoregulation caused by changes in salinity of the environment.

• 대한약리학회:학술대회논문집
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• 대한약리학회 2006년도 The 6th Congress of the Federation of Asian and Oceanian Physiological Societies
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• pp.91.1-91.1
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• 2006

• 대한소아치과학회지
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• 제36권4호
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• pp.640-646
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• 2009

치아에 외상을 받은 경우 치수 생활력의 상실은 흔한 일이다. 치수 생활력을 검사하는 방법으로는 임상적, 방사선학적으로 여러 가지가 있지만, 미성숙 외상치의 경우 일시적 현상과 가성 반응이 나타날 수 있으므로 치수 괴사에 대한 정확한 진단은 매우 어렵다. 생활력을 상실한 치아는 염증성 치근흡수, 치근단 낭종 등의 발생을 방지하기 위하여 치수 치료를 시행한다. 그러나 미성숙 영구치의 경우, 치수 치료를 시행 후 치근 성장이 정지될 수 있어 결과적으로 얇고 짧은 치근이 형성되어 장기적인 예후는 좋지 않다. 본 임상 증례에서는 외상으로 인하여 실활된 초기 영구치에서 치근단부의 최소한의 침습적 치근단 형성술로 계속된 치근 형성을 보여 이에 보고하는 바이다.

• 한국동물학회지
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• 제28권3호
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• pp.151-165
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• 1985

솔나방의 變態에 따른 中腸上皮의 形態的 變化를 終齡幼蟲類에서 踊化直後까지 5단계로 나누어 光學 및 電子顯微鏡을 사용하여 관찰하였다. 終齡類蟲의 中腸上皮는 圓桂狀細胞, 再生細胞 및 內分泌細胞로 구성되어 있다. 終齡幼蟲의 圓桂狀細胞에서는 核으로부터 유출되는 분비물질이 核膜에 규칙적으로 배열되어 관찰되며, 정단부에서는 lysosome이 점차 증가해 간다. 또한, 遊離綠에서는 微細絨毛사이로 팽출한 細胞質突起가 나타나는데 細胞小器官은 관찰되지 않는다. 再生細胞는 分化가 활발해짐에 따라 杯胞가 있는 杯狀細胞型으로 관찰되며, 細胞質에서는 液胞가 점차 증가한다. 踊化直前에는 Ca의 주성분으로 사료되는 물질이 동심원상으로 나타나며 杯胞는 腸內腔으로 분리된다.幼蟲類의 圓桂狀細胞에서 관찰되는 lysosome의 증가, 核物質의 細胞質로 유출, 遊離綠의 細胞質突起는 幼蟲期 中腸上皮의 退化過程을 반영하고 있다고 사료되며, 再生細胞는 杯狀細胞型으로 分化되지만 杯胞가 腸內腔으로 분리되고저 踊化期의 새로운 中腸上皮를 구성한다고 믿어진다.

• Applied Microscopy
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• 제21권2호
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• pp.76-95
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• 1991

A single injection of cadmium chloride (3.75 mg/kg) was made into the peritoneal cavities of albino rats. The cortices of kidney were obtained from the experimental animals at 3 hr., 6 hr., 12 hr., 24 hr. and 36 hr. after administration of cadmium chloride, respectively. The specimens of each experimental animal were prefixed in 2% glutaraldehyde-4% paraformaldehyde solution for $2{\sim}4$ hours, and these specimens were post-fixed in 1% osmic acid. After fixation, the specimens were dehydrated with alcohol and acetate and embedded in Epon 812. Ultrathin sections, $600{\sim}800{\AA}$ thickness were made and stained with uranyl acetate and lead citrate. And all the preparations were observed with Hitachi-600 transmission electron microscope. The results obtained were as follows: 1. The main changes in ultrastructures of the glomeruli observed at 3 hr. after cadmium chloride administration include loss of filtration slit and fenestrae of capillary endothelium that was resulted from thickings of the basal lamina and fusion of pedicels of the podocytes. At 12 hr. after cadmium chloride administration the Bowman's capsules were mostly filled with abnormally thickened and fused pedicels. After 24 hr. however, the only recognized change was loss of fenestrae of the capillary endothelium. And the ultrastructure of the glomeruli were almost normal in 36 hr. after cadmium chloride treatment. 2. At 3 hr. after treatment with cadmium chloride, in the renal tubular cells the vesicles and vacuoles increased in number at the apical portion, of the tubular epithelial cells, the basal infoldings were reduced and the basal lamina was thickened. After 12 hr., a number of phagosomes appeared at the apical portion and the cisternae of rough endoplasmic reticulum were swollen. At 24 hr. after cadmium chloride administration irregularly shaped mitochondria were observed in the apical area, and mitochondria with swollen cristae were found at the basal portion. And after 36 hr. The ultrastructures of the epithelial cells appeared almost normal except for a moderate increase in the number of vesicles and vacuoles. Consequently it is suggested that in albino rats, cadmium chloride induces acute reversible degenerative changes in the glomeruli as well as in the epithelial cells of the proximal convoluted tubules.

• 한국발생생물학회지:발생과생식
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• 제27권4호
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• pp.221-226
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• 2023

A stem cell niche provides an environment that governs stem cell maintenance and division. Thus, the development of a proper niche is of prime importance to stem cell behaviors. Mechanisms of niche development are beginning to be revealed in the Drosophila male gonad. Niche cells are initially dispersed throughout the gonad, then assemble at its apical tip through the anterior migration of posteriorly located niche cells. The molecular mechanisms of this migration and assembly are still poorly understood. Here we show evidence suggesting that Lin28, an RNA-binding protein and regulator of let7 genesis, might be an intrinsic factor for the anterior migration of niche cells. We found that a dispersed, ectopic niche, a phenotype observed with anterior migration defects, occurs in lin28 mutant gonads. This phenotype is rescued by expression of lin28 in the niche cells. These findings suggest that Lin28 might be required for the anterior migration of niche cells.

• Tuberculosis and Respiratory Diseases
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• 제40권3호
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• pp.236-249
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• 1993

연구배경 : 정상 폐상피세포에서는 항상 생성되고 있는 활성산소(oxygen radical)에 의한 유해작용에 노출되어 있고, 이들 유해 산소들은 폐기종과 같은 폐질환의 원인 기전으로 생각되고 있다. 본 연구에서는 이 방법을 이용하여 만든 폐상피세포 단일막에서 전기생리학적인 관점에서 물질의 이동지표인 short-circuit current(Isc)와 조직저항(R)에 대한 활성산소의 하나인 $H_2O_2$(hydrogen peroxide)가 어떤 영향을 미치는지를 연구함으로서 세포생리학적 기전을 구명하고자 한다. 방법 : Tissue culture-treated polycarbonant membrane filter 에서 배양시킨 쥐 제 2 형 폐상피세포 배양 단일막에서 $H_2O_2$의 능동적 이온 이동 (Isc) 과 수동적 용질이동에 대한 조직저항(R)에 미치는 효과를 관찰하였다. 배양 제 3 일과 제 4 일째 단일막을 수정된 Ussing chamber에 설치하고 막 양측에 HEPES-buffered Ringer 용액으로 incubation 하였다. 외부에서 0~100 mM 농도의 $H_2O_2$를 apical 또는 basolateral side에 작용시켜 Isc와 R의 변화를 관찰하였다. 폐상피세포 장벽이 외부의 $H_2O_2$에 대하여 방어작용을 가지는 세포내 catalase 활성도를 측정하고, catalase 억제제인 aminotriazol(ATAZ) 20 mM의 효과도 함께 관찰하였다. 결과 : 이 단일막은 형태학적으로 보아서 in vivo 에서의 포유류 제 1 형 폐상피세포 장벽의 특성을 나타내고 세포들 사이는 tight junction을 이루며(조직저항 R: 2,000 ohm-$cm^2$ 이상) sodium ion의 능동적 이동 (Isc: 5 ${\mu}A/cm^2$)을 보였다. $H_2O_2$는 dose-dependent 양식으로 Isc와 R 모두 감소시켰다. Apical side에 작용하는 $H_2O_2$에 있어서는 60분에 50% 억제하는 농도인 $ED_{50}$는 Isc와 R은 약 4mM 이었으나 basolateral side의 경우는 약 0.04mM 로서 그 작용 강도는 apical에 비하여 약 100배 정도 더 컸다. ATAZ 존재시 apical side의 $ED_{50}$는 0.4mM로 감소하였으나 basolateral side의 경우 변화가 없었다. $H_2O_2$의 제거율은 apical 또는 basolateral side 어느 쪽에 존재하든 같았으며, 세포내 catalase 활성도는세포배양기간이 길어짐에 따라 증가함을 보였다. 결론 : 이상의 실험결과는 basolateral side에 작용하는 $H_2O_2$는 세포내 막구성성분 중 basolateral 측에 존재하는 곳에(예, $Na^+,\;K^+$-APTase) 직접 장애를 미칠 것으로 생각된다. 한편 apical side에 작용하는 $H_2O_2$는 막성분에 도달하기 전에 세포내에 존재하는 catalase에 의하여 대부분 그 작용을 잃게 된다. 결론적으로 Isc와 R로 측정된 폐상피세포 장벽의 특성은 $H_2O_2$에 의하여 손상을 받고 apical side 보다는 basolateral side 측정이 더 손상을 잘 받게 된다.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.133-142
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• 1996

Ten intrabony defects in 10 patients were treated by flap surgery including root surface debridement and placement of an expanded polytetrafluoroethylene(ePTFE) membrane. The membranes were removed after 4-6 weeks. This study was performed to examine the retrived ePTFE membrane by scanning electron microscopy(SEM) for bacterial contamination and adherent connective tissue elements, and to compare it with clinical conditions. The cervical portion of the membrane, which in most cases had become partially exposed to the oral cavity, had a bacterial deposit. Small bacterial colonies and a scatter of single cells in some instances extended into the apical portion of the membrane. Fibroblast-like cells, erythrocytes and fibrous structures were seen in the apical portion of the membrane. Outer surface of membrane tends to more bacterial contamination than inner surface(p<0.01), and upper portions more than lower portions(P<0.01). Comparison of ultrastructural findings and clinical conditions revealed that extent of bacterial contamination of the membrane correlated with gingival inflammation and extent of membrane exposure, but it was not significant statistically. The results suggested that gingival inflammation and membrane exposure affect periodontal regeneration by the use of ePTFE membrane.

• 한국동물위생학회지
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• 제20권1호
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• pp.55-67
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• 1997

The morphological development of lungs in fetuses of 60, 90 and 120 days of gestation and neonates of Korean native goats was investigated by light, scanning and transmission electron mictroscope. The results were summarized as follows ; 1. Gross findings ; In the 60-days-old fetus, the lung was developed and differentiated into six lobes. 2. Light microscopic findings : The gland-like bronchioles were formed in loose mesenchyme at 60 days of gestation and the bronchial wall contained smooth muscles. The loose mesenchyme had been replaced by compact parenchymal tissue at 90 days of gestation and the cartilage plates appeared in bronchial wall which contained blood vessels, submucosal glands and smooth muscles. The lung parenchyma consisted of a fine network of alveoli at 120 days of gestation and the bronchial wall contained well-developed blood vessels, submucosal glands, cartilage plates and smooth muscles. In neonates, the lung tissue was similar to the mature lung tissue and the bronchial wall contained well developed cartilage plates. 3. Scanning electron microscopic findings : The epithelial cells lining the tubules were composed of cuboidal or columnar at 60 days of gestation and the epithelial cells lining the large airways were often ciliated : some were covered with stubby microvilli. The epithelial cells lining the canals were cuboidal at 90 days of gestation and the epithelial cells lining the bronchioles were ciliated cells or nonciliated(clara) cells, The clara cells contained row microvilli. The alvealor development of this stage was rapidly progressed ; the subdivision of canals by alveolar crests and assosiated wall attenuation resulted alveoli at 120 days of gestation and the respiratory bronchioles were lined by ciliated or nonciliated epithelial cells. In neonates, the epithelial cells lining the alveolar walls were mainly covered with pneumocyte type I ; Some were covered with pneu-mocyte type II. 4. Transmission electron microscopic findings : The epithelial cells lining the tubules were adhered with tight junction at apical borders of the adjacent cells at 60 days of gestation, which contained few organells and glycogen. The epithelial cells lining the canals were composed mostly of cuboidal cell at 90 days of gestation and the epithelial cells lining of the bronchioles were ciliated of nonciliated cell, which contained few organelles and abundant glycogen. The epithelial cells lining the alveolar walls were composed of pneumocyte type I and a few pneumocyte type II at 120 days of gestation. The epithelial cells lining of the bronchioles were ciliated or nonciliated cells. In neonates, pneumocyte type I was observed as flat and thin cytoplasmic extension in shape. Otherwise, pneumocyte type II was observed as cuboidal type with apical microvilli and contained osmiophillic lamellar inclusion bodies. Putting these various experiment results together, the lung development was slowly progressed at early stage, which was rapidly progressed in the late stage of gestation.