• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.958-964
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• 2008

In this work, micro-sized dextran particles, which have recently been focused as one of the candidate materials for the Drug Delivery System(DDS), were prepared by means of the Supercritical Antisolvent (SAS) process with $CO_2$. With dimethyl sulfoxide(DMSO) as the solvent, effects of the operating variables such as temperature (308.15~323.15 K), pressure(90~130 bar), solute concentration(10~20 mg/ml), and the molecular weight of the solute(Mw=37,500, 450,000) on the size and morphology of the resulting particles were thoroughly observed. The higher solute concentration led to the larger particles, however, the injection velocity of the solution and pressure did not show significant effects on the resulting particle size. With dextran of the lower molecular weight, the smallest particles were obtained at 313.15 K. On the other hand, the size of the particles from the high molecular weight dextran ranged between $0.1{\sim}0.5{\mu}m$ with an incremental effect of the temperature and pressure. For the solute concentration of 5 mg/ml, the lower molecular weight dextran did not form discrete particles while aggregation of the particles appeared when the solute concentration exceeded 15 mg/ml for the higher molecular weight dextran. It is believed that if the solute concentration is too low, the degree of the supersaturation in the recrystallization chamber would not be sufficient for initiation of the nucleation and growth mechanism. Instead, the spinodal decomposition mechanism leads to formation of the island-like phase separation which appears similar to aggregation of the discrete particles. This effect would be more pronounced for the smaller molecular weight polymer system due to the narrower phase-splitting region.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.275-282
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• 2018

Paeoniae Radix has been used as a traditional medicine for various diseases including hepatic disease. However, the inhibitory effect of Paeoniae Radix on intestinal inflammation has not been fully understood yet. The aim of this study was to evaluate the effect of Paeoniae Radix on colitis induced by dextran sulfate sodium in mice. To investigate the protective effects of Paeoniae Radix, the colitis mice were induced by drinking water containing 5% dextran sulfate sodium for 7 days. Mice were randomized into groups receiving Paeoniae Radix (100 mg/kg), sulfasalazine (150 mg/kg) as a positive control, or water as a negative control. We evaluated the effects of Paeoniae Radix on clinical signs induced by dextran sulfate sodium, measuring weight loss, colon length, and disease activity index. Additionally, to find a possible explanation for the anti-inflammatory effects of Paeoniae Radix, we evaluated the effects of Paeoniae Radix on the interleukin-6 and cyclooxygenase-2 levels in colitis tissue. The results indicated that mice treated with dextran sulfate sodium showed measurable clinical signs, including weight loss and reduced colon length. However, Paeoniae Radix treatment significantly improved the weight loss and disease activity index as clinical symptoms. Moreover, Paeoniae Radix inhibited the interleukin-6 and cyclooxygenase-2 expression levels in colon tissues treated with dextran sulfate sodium. Taken together, the findings of this study suggest that Paeoniae Radix may be useful for treating intestinal inflammation, including ulcerative colitis.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.632-637
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• 2009

Poly(${\varepsilon}-caprolacton$)/ethyl cellulose (PCL/EC) microcapsules containing pluronic F127 were prepared by a spray drying method. The aqueous phase, 20% of pluronic F127 was dissolved in distilled water, and the organic phase, 5% of PCL and EC were dissolved in dichloromethane. The microcapsules were obtained by spray drying the water-in-oil (W/O) emulsion. According to the data of scanning electron microscopy and particle analyzer, tens of micro size microcapsules were observed. On a differential scanning calorimeter, the phase transition temperatures of microcapsules were observed and they were found around those of pluronic F127 and poly(${\varepsilon}-caprolacton$), which were the main components of the microcapsules. At the range of $30{\sim}45^{\circ}C$, temperature-dependent release properties were investigated using fluorescein isothicyanate-dextran (FITC-dextran) and blue dextran as a model drug. When the temperature was increased, the degree of release of microcapsule was also increased. FITC-dextran, the relative low molecular weight, was more released than blue-dextran.

• Korean Journal of Veterinary Research
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• v.34 no.1
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• pp.213-218
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• 1994

복강장기의 유착을 방지하기 위하여 토끼의 공장에 인공창상을 일으키고 sodium carboxymethylcellulose (SCMC)와 dextran 70을 단일 혹은 합제로 사용하여 이들의 유착방지 효능을 조사하였고, 아울러 체중의 변화를 조사함으로써 이들을 사용하였을 때 일어날 수 있는 부작용을 검토하였다. 인공창상에 의한 유착형성 유발빈도와 정도를 알아보기 위하여 토끼를 전신마취시킨 다음 개복수술을 시행하여 공장의 장막에 2cm 폭으로 3곳에 abrasion또는 electrocautery를 실시하였던 바, 이러한 인공창상들이 유의성있는 높은 유착형성율(abrasion, 70%; electrocatuery, 72.7%)과 심한 유착정도를 일으켰으며(abrasion, 1.80; electrocatuery, 2.44), 체중의 감소를 가져왔다(abrasion, -2.5%; electrocautery; 9.9%). Abrasion보다는 electrocatuery에 의한 자극이 더욱 심한 유착정도 및 체중감소를 보였으며 심할 경우 폐사를 일으키기도 하였다. 이러한 유착을 효과적으로 방지하기 위하여 1, 2, 3%의 SCMC 및 6, 10%의 dextran 70 용액을 단일 또는 합제를 만들어 abrasion방법으로 공장에 인공창상을 일으킨 토끼의 복강내에 주입하고 수술 4주후에 복강을 열어 유착형성율을 조사하였던 바, 1% SCMC와 10% dextran 70의 합제(Synthetic soln)에서 가장 낮은 유착형성율(0%)을 보여 유착방지 효과가 가장 뚜렸하였다. 아울러 수술 4주일후 체중의 변화도 유의하게 일으키지 아니 하였다. 그러므로 유착방지제로서 synthetic solution을 사용하는 것이 가장 효과적이라고 사려된다.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.735-742
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• 1996

Polymeric matrices were prepared with dextran and silver sulfadiazine by adding glycerine as a plasticiser. Namely, the release rate of the drug from the polymeric matrix formulations in dissolved phases was determined in a phosphate buffer solution. The results were as follows : The drug release time was delayed as drug loading contents increased, whereas it decreased as the glycerine concentration increased. The drug release time was not changed with varying the molecular weight of the dextran. The apparent release rate constant (k) increased as the composition of silver sulfadiazine and glycerine was increased. But the apparent release rate constant (k) was not changed with increasing molecular weight of the dextran.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.219-222
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• 1999

A simple sequence of membrane concentration and DEAE-Cellulose chromatography has been optimized to give a purified dextransucrase from Leuconostoc mesenteroides B-512FMCM with the highest specific activity (248.8 IU/mg protein) ever reported in high yield (overall 88.7%) for dextransucrase. When there was no sucrose in the dextransucrase and the dextran reaction digest, the dextransucrase hydrolyzed glucose from dextran. The glucose was transferred to the other glucoses from dextran and formed isomaltose and isomaltodextrin. The transglycosylation efficiency of glucose from dextran was much higher with acceptors. The dextransucrase can be used for the production of various kinds (or structures) of oligosaccharides using dextran and various acceptors with almost 100% theoretical yield.

• Microbiology and Biotechnology Letters
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• v.27 no.4
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• pp.304-310
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• 1999

We have developed a new process for the production of new structure oligosaccharides using the mixed-culture fementation of Lipomyces starkeyi KSM22 and leuconostoc mesenteroides B-512FMCM.L.starkeyi KSM22 produces a novel DXAMase(an enzyme containing both dextranase and amylase activities). It hydrolyzes the soluble starch and dextran. The hydrolyzates were used as acceptors for dextransucrase of L.mesenteroides to synthesize the new oligosaccharides(NOS). In fermentation, as the concentration of sucrose was increased from 9%(w/v) to 15%(w/v), the yields of dextran(sum of dextran I, MW=66kD, and dextran II, MW=21kD) was increased from 12.7% to 42.5%, and NOS was increased from 3.9% to 5.2% of the theoretical, respectively. The NOS of dp(degree of polymerization) 5 and over was increased from 33.1% to 58.3% of the total NOS. The NOS showed heat resistant up to 12$0^{\circ}C$ and was stable at pHs ranged from 2 to 6. The NOS decreased the pH changes in the culture of S. mutans, and also showed inhibitory effects on the growth of S. aureus or S. typhimurium.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2542-2546
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• 2010

The objective of this paper was to investigate the effect of dextran gel on preparation of nano-liposomes loaded with ginkgolide. During preparation, Sephadex G75, G50 and G25 were added in the aqueous phase respectively. From the experiment, nano-liposomes prepared by dextran gels were found spherical and smooth. The result indicated that aperture of dextran gels were narrower, particle size of nano-liposomes was smaller (207.13 ~ 89.16 nm) and zeta potential was greater (-36.2 ~ -29.5 mV) in more negative. The study also revealed that differences of the entrapment efficiency and drug loading among the three types of nano-liposomes were not significant. In vitro drug release test demonstrated that nano-liposomes had a better controlled release. To conclude, by using dextran gel in the preparation of nano-liposome loaded with ginkgolide, the particle size could be effectively controlled and the drug stability could be improved.

• Journal of Veterinary Clinics
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• v.21 no.4
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• pp.349-354
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• 2004

The effectiveness of a synthetic solution of sodium carboxymethy1cellulose (SCMC) and dextran in the prevention of adhesion formation following intestinal anastomosis of intestine in dogs was elucidated and compared with Interceed. Following induction of adhesion on jejunum of dogs by resection and intestinal anastomosis, the dogs were infused with a synthetic solution of 1% SCMC and 10% dextran in saline in the abdominal cavity at the dose of 5ml/kg of body weight or treated with Interceed membrane. Fourteen days after operation, all the dogs showed adhesion of anastomotic sites to surrounding tissues. The average score of adhesion was 0.50, 0.60 and 0.80 in the dogs infused with the synthetic solution, Interceed membrane and saline solution, respectively. The synthetic solution showed better result of adhesion prevention than Interceed or saline solution. No significant change of body weight, vital signs, hematological values and side effects after operation was found in each group. Therefore, a synthetic solution which is combined with 1% SCMC and 10% dextran in saline can be effectively used for the prevention of adhesion formation comparable to Interceed membrane following intestinal anastomosis in the dogs.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.586-590
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• 2019

The aim of this study was to fabricate a dextran polyelectrolyte multi-layer on a bare metal stent (BMS) and to evaluate bio-physical properties of the layer. Diethylaminoethyl-dextran (DEAE-D) as a polycation and dextran sulfate (DS) as a polyanion were successively coated on the bare metal stent by a well-known layer-by-layer procedure. The morphology of the stent surface and its cell adhesion were studied after each coating step by scanning electron microscopy. The stent showed more blotched and slightly rougher morphology after dextran-DS coating. The contact angle of the DEAE-DS group ($39.5{\pm}0.15^{\circ}$) was significantly higher than that of the BMS group ($45.16{\pm}0.08^{\circ}$), indicating the improvement of hydrophilic. The SMC proliferation inhibition in the DEAE-DS-coated stent group ($20.9{\pm}0.04%$) was stronger than that in the control group ($21.7{\pm}0.10%$ in DS-coated group only). The DEAE-DS coating is desired for stent coating materials with biocompatibility and anti-restenosis effect.