• 대한소아치과학회지
• /
• 제26권1호
• /
• pp.77-87
• /
• 1999

이 연구는 치아우식증의 주요 원인균인 Streptococcus mutans의 치태형성과 증식에 대한 Streptococcus oralis의 영향을 조사하고자 하였다. 이를 위해 S. mutans 단독 배양과 S. mutans와 S. oralis 혼합 배양후 형성된 치태 무게와 생균수를 측정 비교하였다. 또한 치태형성과 생균수에 영향을 미치는 요소들에 대해 조사하여 다음과 같은 결과를 얻었다. 1. S. mutans와 S. oralis의 혼합배양시 S. mutans 단독배양에 비해 치태무게와 생균수가 감소되었다. 2. S. mutans 단독배양에 10mM의 포도당을 첨가한 군은 첨가하지 않은 군보다 치태무게가 증가되었으나, S. mutans와 S. oralis의 혼합배양에 10mM의 포도당을 첨가한 군은 첨가하지 않은 군과 차이가 없었다. 3. S. mutans 단독배양에 10mM의 과당을 첨가한 군은 첨가하지 않은 군보다 치태무게가 증가되었고, S. mutans와 S. oralis의 혼합배양에 10mM의 과당을 첨가한 군도 첨가하지 않은 군보다 치태무게가 증가되었다. 4. S. mutans와 S. oralis의 혼합농도를 달리하여 배양했을때 S. oralis의 혼합농도가 높아질수록 치태무게와 생균수는 감소되었다. 5. 배양시간(6, 9, 12, 15시간)에 따른 치태무게와 생균수는 S. mutans 단독배양에 비해 S. mutans와 S. oralis 혼합배양시 배양 12시간 이후 급격히 감소되었다. 6. S. mutans와 S. oralis의 혼합배양에 $H_2O_2$를 소비하는 Staphylococcus epidermidis를 첨가한 군은 첨가하지 않은 군보다 치태무게와 생균수가 증가되었다. 이상의 결과로 S. oralis는 S. mutans와 혼합배양 시 S. mutans의 증식과 인공치태의 생성을 억제함을 알 수 있었고, 이는 S. oralis가 $H_2O_2$를 분비함으로써 얻어진 결과임이 시사되었다.

• 한국어병학회지
• /
• 제10권1호
• /
• pp.1-14
• /
• 1997

양식 농어 치어에 발생하는 포도상구균증의 원인균에 대한 생화학적 성상, 생물학적 성상, 약제 감수성 및 병원성을 검토하였다. 병어의 간, 신장, 비장 및 뇌로부터 원인균을 분리하였으며, 생물학적 생화학적 성상을 조사한 결과 본 균을 Staphylococcus epidermidis로 동정하였다. S. epidermidis에 감염된 농어 치어의 외부 소견은 안구 충혈 및 백탁이 주증상이었고, 해부학적 소견은 뇌출혈, 간울혈, 신장 및 비장의 팽대가 특징적였다. 분리균주는 BHIA, HIA 및 Staphylococcus No. 110에서 잘 발육하였으며, 식염 농도 0~9% (최적 염분 : 1~3%), $10\sim45^{\circ}C$(최적 온도 ; $35\sim40^{\circ}C$) 및 pH 4~10(최적 pH : 8)에서 발육하였다. DNase, coagulase에는 모든 균주가 음성였으며, 용혈성은 양성을 나타내었고, urease 양성, novobiocin 저항성에는 음성을 나타내었다. 모든 균주는 탄수화물 분해시 가스를 생성하지 않았고 혐기적 조건하에서 포도당과 maltose를 분해했다. 호기적 조건하에서 모든 균주는 포도당, galactose, sucrose, maltose 및 dextrin을 분해하였다. $1.7{\times}10^{10}$ viable cells/$m\ell$를 근육 주사한 실험구에서는 모든 접종어에 강한 병원성을 나타내었으나, $1.7{\times}10^4$ viable cells/$m\ell$를 접종한 실험구에서는 약한 병원성이 나타났다. 분리균은 bacitracin, erythromycin, norfloxacin 등에 감수성을 나타냈으나, colistin, gentamicin, nalidixic acid 등에는 내성을 나타냈다. 병어의 병리조직학적 관찰 결과 뇌의 소상 울혈, 간 실질세포의 퇴행성 병변 및 신장 조직에서 뇨세관 상피세포의 분리와 괴사가 나타났다.

• Applied Microscopy
• /
• 제21권2호
• /
• pp.39-56
• /
• 1991

The development of notochordal cells of nucleus pulposus was studied with electron microscope in human fetuses ranging from 30 mm to 260 mm crown-rump length. At 30 mm fetus, primitive notochordal cells were large with central nucleus, few organelles, and their cytoplasm usually contained dense glycogen and fine filaments. Notochordal cells at all ages contained bundles of fine filaments of indeterminate nature. One unusual feature of fetal notochordal cells was the consistent presense of rough endoplasmic reticulum surrounding poorly developed mitochondria. At 50 mm fetus, notochordal cells formed dense masses with interdigitating cell membranes connected by a variety of cell to cell junctions. With increasing age, the cell connections became slender threaded cytoplamic extending from cell and enclosed large extracellular space. Chondrocyte-like cells appeared to be separated by large volumes of extracellular matrix. Viable notochordal and condrocyte-like cells existed in specimen from all age. The extracellular spaces were filled with fibrillar and granular material by 90 mm fetus. Necrotic cells were distinguished by loss of their membrane integrity, vacuolization of their organelles, and the presence of dense osmiophilic masses. In adult tissue, notochordal cells became rounded or irregular in shape and developed a pericellular matrix consisting of collagen fibrile, and dense particle. The structure of notochordal cells and their persistance in the nucleus pulposus after fetal life suggested that they may have a significant role in the formation and maintenance of the nucleus pulposus. The presence of Golgi complex and well-developed endoplasmic reticulum in chondrocyte-like cells suggested that they are capable of producing and maintaining the extracellular matrix.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2019년도 전력전자학술대회
• /
• pp.50-52
• /
• 2019

Dynamic resistance equalization is a viable technique to balance SOC of cells in a parallel-connected battery configuration due to high equalization performance, simplicity and low-cost. However, an inappropriate design of the equalization resistor can degrade the equalization performance and increase the power loss. This paper proposes an optimization process to design the equalization resistors to minimize power loss and equalization error. The simulation results show that the optimally designed resistor significantly enhance the performance in comparison with the conventional fixed-resistor equalization.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권12호
• /
• pp.4849-4852
• /
• 2015

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been investigated as an effective agent to treat various cancers. Cancer stem cells are resistant to TRAIL treatment, but the mechanism of TRAIL resistance remains unknown. In this study, brain cancer stem cells were isolated by CD133 magnetic sorting, and the number of CD133 positive cells detected by flow cytometry. The self-renewing capacity of brain cancer stem cells was examined by a neurosphere formation assay, and the percentage of cell death after TRAIL treatment was examined by an MTS assay. Expression of DR5, FADD, caspase 8 and BCL2 proteins was detected by western blot. The amount of CD133 positive cells was enriched to 71% after CD133 magnetic sorting. Brain cancer stem cell neurosphere formation was significantly increased after TRAIL treatment. TRAIL treatment also reduced the amount of viable cells and this decrease was inhibited by a caspase 8 inhibitor or by the pan-caspase inhibitor z-VAD (P<0.05). Brain cancer stem cells expressed lower levels caspase 8 protein and higher levels of BCL2 protein when compared with CD133 negative cells (P<0.05). Our data suggest that TRAIL resistance is related to overexpression of BCL2 and low expression of caspase 8 which limit activation of caspase 8 in brain cancer stem cells.

• Journal of Pharmaceutical Investigation
• /
• 제32권4호
• /
• pp.285-290
• /
• 2002

In order to assay the efficacy of newly synthesized antiviral compounds, in vitro studies of their active intracellular phosphorylated metabolites were established as compared with Zidovudine (ZDV). Antiviral base analogs require intracellular phosphorylation prior to the inhibition of HIV replication. Therefore, antiviral drugs concentrations in plasma have not reflected any direct relationship with activity or toxicity. A method has been developed to measure the concentration of total phosphorylated metabolites inside peripheral blood mononuclear cells using modified commercial radioimmunoassay (RIA). ZDV 5'-monophosphate was synthesized and used as a procedural control for RIA modification. PBMCs were isolated from whole blood and incubated with ZDV for 20 h to allow metabolic phosphorylation. Viable cells were extracted overnight with 60% methanol. After evaporation, the extract was reconstituted in Tris buffer. Samples were split into two fractions, one of which was treated with alkaline phosphatase (AP) to liberate phosphate groups. Concentrations of phosphorylated metabolites were determined by subtracting thε concentration of non-AP-treated fraction from that of the treated fraction. Recovery of phosphorylated ZDV from cell extracts was approximately 90%, and reproducibility was acceptable (coefficients of variation <15% for concentrations${\geq}$0.25 ng/mL). Intracellular concentrations $(0.135{\sim}5.019\;nmole/10^6\;cells)$ followed a nonlinear dose-response relationship over the range $0.015{\sim}2.996mM$ extracellular ZDV, with concentration-dependant saturation.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권3호
• /
• pp.1169-1173
• /
• 2015

Background: Paris polyphylla (Chinese name: Chonglou) had been traditionally used for a long time and shown anti-cancer action. Based on the previous study that paris polyphylla steroidal saponins (PPSS) induced cytotoxic effect in human lung cancer A549 cells, this study was designed to further illustrate the mechanisms underlying. Materials and Methods: The mechanisms involved in PPSS-induced A549 cell death were investigated by phase contrast microscopy and fluorescence microscopy, flow cytometry and western blot analysis, respectively. Results: PPSS decreased the proportion of viable A549 cells, and exposure of A549 cells to PPSS led to both apoptosis and autophagy. Apoptosis was due to activations of caspase-8, caspase-3, as well as cleavage of PARP, and autophagy was confirmed by up-regulation of Beclin 1 and the conversion from LC3 I to LC3 II. Conclusions: PPSS was able to induce lung cancer A549 cell apoptosis and autophagy in vitro, the results underlining the possibility that PPSS would be a potential candidate for intervention against lung cancer.

• 한국수산과학회지
• /
• 제49권5호
• /
• pp.589-593
• /
• 2016

Propionibacterium acnes infection in skin tissue often causes acne vulgaris, commonly characterized by inflammatory papules, pustules, and nodules. Chitosan and its derivatives possess strong anti-inflammatory effects. In this study, the anti-inflammatory activity of chitosan-phytochemical conjugates on P. acnes-infected human skin keratinocytes (HaCaT) was evaluated. We designed a model of P. acnes-induced inflammation in viable HaCaT cells. Nitric oxide (NO), an inflammatory marker, was successfully elevated by P. acnes infection in HaCaT cells in a dose-dependent manner. Furthermore, the levels of NO were reduced by treatment with chitosan-phytochemical conjugates (chitosan-caffeic acid, -ferulic acid and -sinapic acid) in a dose-dependent manner. Among these conjugates, chitosan-caffeic acid exhibited the strongest NO suppression in HaCaT cells infected with P. acnes. The results obtained in this study suggest that chitosan-phytochemical conjugates could be used as a potential therapeutic agent against acne vulgaris.

• 대한한의학회지
• /
• 제24권2호
• /
• pp.204-212
• /
• 2003

Current therapy for acute ischemic stroke is highly focused on neuroprotective agents, and many herbal medicines have been challenged for experimental models. The aim of this study is to investigate whether Angelicae gigantis Radix can protect nerve cells against ischemic neural damage of middle cerebral artery occlusion (MCAO) in rats' brains. Rats were treated with Angelicae gigantis Radix immediately after 2 hours of MCAO for 7 days. On the 7th day, the brains of the rats were sliced through the hippocampus and dyedby c-Fos immunohistochemistry stain and cresyl violet stain for microscopic examination. The number of viable neurons and c-Fos immunoreactive cells in CA1 regions was counted. MCAO caused significant decrease in density of neurons and c-Fos immunoreactive cells compared to those of sham-operated rats. Administration of Angelicae gigantis Radix significantly elevated MCAO-induced decrease in density of neurons and c-Fos immunoreactive cells. These results suggest that the neuroprotective effect of Angelicae gigantis Radix against focal cerebral ischemia is related to c-Fos gene expression. Thus, these findings indicate that Angelicae gigantis Radix can be used for treatment and prevention of cerebral ischemia.

• 한국미생물·생명공학회지
• /
• 제23권3호
• /
• pp.346-351
• /
• 1995

To produce ethanol from Jerusalem artichoke powder efficiently, Kluyveromyces marxianus F043 cells were encapsulated in 2% sodium alginate and were cultured in a countinuous reactor to investigate the fermentation properties. Immobilized K. marxianus F043 cells were activated for 48 hours in a fermentor for continuous ethanol production. The culture in a CSTR using a Jerusalem artichoke substrate treated with 2% cellulase showed a decrease in ethanol concentration and an increase in residual saccharide concentration with a increasing dilution rate. Optimum conditions for high ethanol productivity and low residual saccharide output were clarified to be given at a dilution rate of 0.2 h$^{-1}$ and a Jerusalem artichoke medium concentration of 75 g/l. Ethanol productivity of 3.1 g/l-h and saccharide utilization of 62.6% were obtained under the optimum condition. When the fermentation was performed for 3 weeks under these conditions, the effluent medium showed stable ethanol concentrations of 16.3 - 17.9 g/l and viable cells of 6.60-7.16 log cells/ml without contamination. Trace amounts of methyl, n-propyl, iso-butyl, isoamyl alcohols besides ethanol were detected.