• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.12 s.243
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• pp.1615-1620
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• 2005

We present a novel flow-rate independent cell counter using a fixed control volume between double electrical sensing zones. The previous device based on the single electrical cell sensing in a given flow-rate requires an accurate fluid volume measurement or precision flow rate control. The present cell counter, however, offers the flow-rate independent method for the cell concentration measurement with counting cells in a fixed control volume of $22.9{\pm}0.98{\mu}{\ell}$. In the experimental study, using the RBC (Red Blood Cell), we have compared the measured RBC concentrations from the fabricated devices with those from Hemacytometer. The previous and present devices show the maximum errors of $20.3\%\;and\;16.1\%$, which are in the measurement error range of Hemacytometer (about $20\%$). The present device also shows the flow-rate independent performance at the constant flow-rates ($5{\mu}{\ell}/min$ and $10{\mu}{\ell}/min$) and the varying flow-rate (4, 2, and $4{\mu}{\ell}/min$). Therefore, we demonstrate that the present cell counter is a simple and automated method for the cell concentration measurement without requiring an accurate fluid measurement and precision flow-rate control.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.27-35
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• 2003

1. 목적 생체재료의 생체친화성을 증진시키고 치유를 촉진하기 위한 목적으로 생체재료의 생화학적 표면개질에 관한 연구가 널리 진행되고 있다. 이와 같은 목적으로 이용되어 온 부착분자에는 아미노산, 펩타이드, 단백질, 효소 및 성장인자들을 들 수 있으며, 이들 분자들을 금속, 골대체물질 및 폴리머와 같은 생체재료의 표면개질에 이용하여 왔다. 이 연구의 목적은 생체적합성이 우수하고 생분해성을 지닌 키토산으로 얇은 막을 제작한 후, 세포외 기질의 구성성분 중 세포부착에 관여하는 RGD 펩타이드를 부착시킨, 표면개질 키토산막의 생물학적 영향을 MG-63 조골양세포를 이용하여 관찰하는 것이다. 2. 방법 2% acetic acid에 키토산 가루를 녹여 만든 2% 키토산 용액으로 24-well 배양접시의 표면을 도포 후 24시간 동안 건조시켜 키토산막을 제작하였다. GRGDS 펩타이드를 cross-linker(EDC, NHS) (Sigma, MO, USA) 용액과 반응시켜서 펩타이드의 카르복실기를 활성화시켰다. 이들을 PBS 완충용액으로 수화시킨 키토산막과 결합시켜 펩타이드의 활성화된 카르복실기와 키토산의 아민기 간에 안정적인 아미드 결합(amide bond)이 형성되도록 하였다. 하루 동안 반응을 일으킨 후 PBS 완충용액과 증류수로 씻어내고 냉동 건조시킴으로써 GRGDS가 결합된 키토산막을 제작하였다. 재료 표면의 화학 성분을 알아보는데 사용되는 방법의 일종인 X-ray photoelectron spectroscopy(XPS) 분석을 통하여 부착분자가 키토산막에 결합된 여부를 확인하였다. GRGDS 펩타이드에 요오드를 결합시킨 후, 이것을 키토산막에 공유 결합시키고 XPS를 통해 요오드가 재료 표면에서 검출되는지를 검사하였다. 요오드가 검출된다면 이것은 키토산막 표면에 실제로 GRGDS 펩타이드가 존재하는 것을 의미하게 된다. 표면개질된 키토산막에 사람조골양세포인 MG-63을 접종하여 이를 실험군으로 하였고, 표면이 개질 되지 않은 키토산막을 대조군으로 하였다. 세포부착의 최적화 농도를 확인하기 위하여 GRGDS를 0.01, 0.05, 0.1, 0.25, 0.5, 1.0mg/ml의 농도로 준비하였다. 배양 후 1일, 7일째에 각 well에서 trypsin EDTA를 이용하여 세포를 분리한 후, 이를 원심 분리하여 세포수측정기를 이용하여 부착 세포의 수를 측정하여 세포의 부착 정도를 비교하였다. 배양 2시간, 24시간 후 주사전자현미경을 이용하여 키토산막에 부착된 세포의 양상을 관찰하였다. 3. 결과 XPS를 통한 표면의 화학 성분 분석 결과 GRGDS 펩타이드를 결합시킨 키토산막에서 요오드가 검출되었으며 펩타이드를 부착하지 않은 대조군에서는 검출되지 않았다. 따라서 cross-linker를 이용한 펩타이드와 키토산막의 공유결합을 확인할 수 있었다. 세포 배양 후 1일째 부착된 세포 수를 측정한 결과 0.1mg/ml 이상의 GRGDS 펩타이드 농도로 공유 결합시킨 키토산막에서 부착 세포 수가 다른 농도에 비해 유의성 있게 많이 관찰되었다. 이 농도 이하에서는 대조군과 실험군간에 세포부착의 유의한 차이가 없었다. 따라서 주사전자현미경을 이용한 부착 세포의 양상에 관한 관찰은 0.1mg/ml 농도의 펩타이드를 이용하였다. 세포 배양 7일째, 부착된 세포 수 측정 결과 GRGDS의 농도에 따른 유의성 있는 차이가 없었으며, 실험군과 대조군간에도 유의성 있는 차이가 없었다. 주사전자현미경 관찰결과 2시간 및 24시간 배양된 실험군 모두에서 별모양의 세포들이 키토산막 표면에 편평하게 잘 부착되어 있으며 많은 위족이 발달된 소견을 보인 반면, 대조군에서는 원형 또는 다각형 모양의 세포들이 실험군에 비해 부착이 덜 되어있는 양상을 보였다. 이 연구를 통하여 기능성 펩타이드를 생체재료의 표면에 공유결합 시키는 방법을 확립할 수 있었으며, RGD 펩타이드의 공유결합으로 표면개질된 키토산막이 조골세포의 부착능을 증진시킬 수 있음을 확인하였다. 표면개질된 생체재료를 소, 중동물에 적용시켜 생체 내에서의 생물학적 영향을 평가할 필요가 있으며, 이 실험의 결과는 향후 다양한 기능성 부착분자를 선발, 고안하여 임플란트용 생체재료의 표면개질에 이용하는 이른바 모방생체재료분야에 널리 활용될 수 있을 것으로 생각된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.304-313
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• 2004

Xylitol, a five-carbon natural sugar alcohol, is widely used non-cariogenic sugar substitute. In present study, the effects of xylitol on the expression of mRNA for glucosyltransferase which synthesizes glucan from sucrose were detected by Fluorescent in situ hybridization (FISH) and flow cytometry. FITC fluorescences for mRNA of gtfB, gtfC and gtfD were decreased further with increasing concentration of xylitol from 1% to 10% when detected by FISH. Flow cytometric analysis also showed that the expression of gtfB, gtfC and gtfD was increased by the addition of sucrose and decreased by the addition of xylitol to BHI broth containing 1% sucrose. In conclusion, the expression of gtfB, gtfC and gtfD mRNA was decreased by the addition of xylitol.

• Korean journal of applied entomology
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• v.10 no.2
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• pp.103-107
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• 1971

In this report, an experiment has been conducted to test the quantitative changes of nucleic acids in the nuclei of the epidermal cell of the galls, caused by Eriophyes kuko Kishida on the leaf of Lycium chinense Mill by means o( microspectrophotometric techniques, the two-wave-length methods. And the sizes of the epidermal cells and nuclei have been measured. The experimental results were summarized as follows: 1) It has been found that as the gall grows, the diameter of the epidermal cells and their nuclei increased and they were larger than those of tile healthy ones. 2) Microspectrophotometric measurement of nuclei by the 'Two-wave-length method' after staining with Feulgen reagent showed no changes in DNA content in the early stage of the gall. As the gall matured, however, DNA content of the gall increased more than that of the healthy leaf. 3) RNA-measurement of nuclei stained with Azur-B in DNase treated epidermal cells of the gall revealed that temporary increase in RNA content occurred in early to middle stages after the gall formation. As the gall matured, however, RNA content of the gall decreased more as against that of the healthy leaf.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.49-56
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• 2010

Developments of radioprotective agents are important issues for minimizing the troubles and the effective treatments in radiotherapy. But few agents are useful in clinical and practical fields. It was shown that trace elements in alcohol beverages might have radioprotective effect. In this study, the types of cell death of lymphocytes according to the commercial alcohol beverage was investigated. Normal healthy volunteers ingested distilled water, beer or soju containing $81.5mg{\cdot}dl^{-1}$ ethyl ahcohol, respectively. After 2 hours, their blood were sampled with their consents. Fraction of lymphocytes was isolated by density gradient method with Histopaque-1077 (Sigma) and irradiated with dose from 0.5 to 5 Gy. After 60 hour incubation, the cells were harvested and analysed by flow cytometry. Cell viability was decreased by dose dependent manner. Cell viability of beer group was reduced about 15% compared with control group. Apoptosis in soju group was reduced about 20% compared with control group. Apoptosis of beer and control groups are similar. Necrosis of soju group significantly increased about 35% compared with control group. Early apoptosis of beer group was increased compared with control group. Early apoptosis of soju group was decreased about 25% compared with control group. Late apoptosis of beer and control group was increased by dose dependent manner. Late apoptosis of soju group was increased about 20-30% compared with control group. Late apoptosis of soju was increased and the radioprotective effect of soju was minimal because late apoptosis induced the cell necrosis. In case of soju trace elements, total cell apoptosis was decreased about 20% and early cell apoptosis was remarkably low. In this case, mitotic cells death may be dominant mechanism. Therefore, trace elements in soju may not be effective radioprotective agents.

• Journal of Yeungnam Medical Science
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• v.6 no.2
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• pp.13-22
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• 1989

To investigate the effect of diazepam on the contractility of the intestinal smooth muscle, longitudinal muscle strip isolated from rat ileum was prepared for myography in isolated organ bath. 1) Basal tone of ileal muscle was reduced by diazepam concentration-dependently. 2) Higher concentrations(30 and 100 microM) of diazepam inhibited(p<0.05, p<0.001) the carbachol-induced contraction in a concentration-dependent manner ; but lower concentration of diazepam(10 microM) enhanced(p<0.05). 3) Histamine-induced contraction was inhibited by pretreatment with diazepam in a concentration-dependent manner. 4) $Ca^{++}$-induced tension recovery in calcium-free solution was inhibited in the presence of diazepam concentration-dependently. These results suggest diazepam reduces the contractility of the longitudinal muscle isolated from rat ileum via interference with influx of calcium into the muscle cells.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.4
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• pp.281-288
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• 2010

In this study, we investigated anti-oxidative effects of Duchesnea indica extracts by using Oxygen Radical Absorbance Capacity (ORAC). The extracts were prepared with 0 %, 30 %, 50 %, 70 % and 100 % aqueous ethanol respectively. The 30 % EtOH D. indica extract showed higher ORAC activity than the other extracts. Therefore, we performed in vitro studies on cytotoxicity of NIH-3T3 cells and MMP-8 collagenase inhibition using by the 30 % EtOH extract. The 30 % EtOH extract showed no cytotoxicity and significant inhibition on MMP-8 collagenase. And we performed clinical studies for the anti-wrinkle effect of the Di-Wrinkle Free Cream. The cream formula was prepared with 2 % arbutin and 1 % D. indica extract. Twenty one healthy women volunteers, ages of 35 and 50, applied the cream on their faces twice a day for 8 weeks. The skin was evaluated with PRIMOS (phaseshift rapid in vivo measuring of human skin) system and analyzed by the student's paired t-test. The wrinkles on the eye region were reduced by 13 % based on the PRIMOS system after 8 weeks. In the safety study of the Di-Wrinkle Free Cream, no symptoms were observed such as erythema, edema, scaling, itching, stinging, burning, tightness and prickling by visual observation and medical examination of volunteers for 8 weeks. Moreover, there was no noticeable skin disorder during experience period. These results suggested that D. indica extracts could be applied as cosmeceuticals effective for anti-wrinkle.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.236-241
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• 2005

To investigate the bioactivities of Solidago virga-aurea var. gigantea Mig. Root (SVR), we studied the effect of a SVR methanol extract on the activity of bone metabolism. Spraque-Dawley three-week-old female rats were randomly assigned to groups as follows : non-supplemented rats and supplemented with SVR at 10, 50, 100 mg/kg bw/day. Every week determined weight gain and food intake, urine and blood examination of mineral content of calcium and phosphorus was performed each at experimental periods of 3 and 9 weeks respectively; bone mineral density and bone mineral content were also assayed. There were no significant differences in body weight or feed efficiency ratio levels. However, the biological value of calcium and phosphorus excretion in the group supplemented with SVR extract decreased significantly more than that in the group not supplemented with SVR extract. Also, spine BMD, femur BMC and pelvis BMC per weight were significantly greater on SVR extract supplemented groups than that of the control group. In conclusion, it might be expected that methanol extract of SVR does not impair the growth of rats and may improve bone metabolism in rats.