• Molecules and Cells
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• v.24 no.1
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• pp.9-15
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• 2007

To investigate the effects of chitosan on the redifferentiation of dedifferentiated chondrocytes, we used chondrocytes obtained from a micromass culture system. Micromass cultures of chick wing bud mesenchymal cells yielded differentiated chondrocytes, but these dedifferentiated during serial monolayer subculture. When the dedifferentiated chondrocytes were cultured on chitosan membranes they regained the phenotype of differentiated chondrocytes. Expression of protein kinase $C{\alpha}$ ($PKC{\alpha}$) increased during chondrogenesis, decreased during dedifferentiation, and increased again during redifferentiation. Treatment of the cultures with phorbol 12-myristate 13-acetate (PMA) inhibited redifferentiation and down-regulated $PKC{\alpha}$. In addition, the expression of p38 mitogen-activated protein (MAP) kinase increased during redifferentiation, and its inhibition suppressed redifferentiation. These findings establish a culture system for producing chondrocytes, point to a new role of chitosan in the redifferentiation of dedifferentiated chondrocytes, and show that $PKC{\alpha}$ and p38 MAP kinase activities are required for chondrocyte redifferentiation in this model system.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2004.04a
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• pp.97-100
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• 2004

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.973-978
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• 2006

This study was conducted to investigate the solubility, antioxidative and antimicrobial activity of the freeze dried chitosan-ascorbate (CAs) and chitosan-acetate (CAc). In the results of solubility, CAs was soluble over 0.5% in distilled water, vinegar, green tea, soju (distilled liquor), beer and red wine, while it was not soluble in soy sauce, soy milk, milk, orange juice, coffee, sesame oil, soy milk and soybean oil. The solubility of CAc in the liquid foods was similar to those of CAs, but it was soluble less than 0.1% in beer, and formed curd in red wine. Electron donating activity, antioxidative activity and SOD activity of CAs were 48.2, 90.6 and 67.5%, respectively, while the activities of the CAc were 0, 40.0 and 10.0%, respectively. The minimal inhibitory concentrations of CAs and CAc were $200\;{\mu}g/disc$ against Bacillus circulans, Bacillus brevis, Bacillus licheniformis, Bacillus arabitane and Bacillus sterothermophillus, $400\;{\mu}g/disc$ against Escherichia coli O157, Listeria monocytogenous, Bacillus cereus and Bacillus subtilis. There was no significant difference in Hunter's L* value between CAs and CAc $(81.95{\sim}82.97)$, but Hunter's a* and b* values of the CAs was higher than those of CAc. While sour and bitter tastes of CAs were lower than those of CAc, there was no significant difference in astringent taste. From these results, it suggested that CAs has more extensive utility in liquid foods with antimicrobial and antioxidant activity as well as sensory quality compared to CAc.

• Journal of Pharmaceutical Investigation
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• v.25 no.1
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• pp.19-29
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• 1995

The study was carried out to develop useful formulation for omeprazole(OMP) through OMP-ethylendiamine complex(OMPED), and the pharmaceutical properties of formula were tested to find out the difference in vivo behaviors of formulations between the free and complexed OMP. Oral and suppository dosage forms were also formulated and the dissolution profiles and pharmacokinetic parameters were measured to observe the difference in bioavailability between the free and complex form, and the correlation between dissolution rate and bioavailability was evaluated. The results are summarized as follows; In the case of formulation for oral administration, the release of OMP from enteric OMPED pellets was found satisfactory to the requirement standard and no decomposition of OMP in the pellets was found in acidic solution. Therefore the enteric OMPED pellets are anticipated to be a stable formulation. The release of OMP from OMPED tablet with chitosan as excipient and coated with cellulose acetate phthalate was found to be significantly retarded. The results of bioavailability test for OMP and OMPED tablets with lactose-excipient showed that the AUC value of OMP tablet was $116.89\;{\mu}g\;{\cdot}\;min/ml$, that of OMPED tablet was $161.10\;{\mu}g\;{\cdot}\;min/ml$, respectively. The reason why was thought that OMP decomposes more readily in body than OMPED, and the AUC of the tablet with chitosan-excipient and coated with cellulose acetate phthalate was most enhanced. In the case of bioavailability for suppositories with OMP, $OMP-{\beta}\;-cyclodextrin$ complex and OMPED, the AUC of OMPED suppository was most increased. From the above results, it is thought that the more stable and bioavailable oral or rectal dosage forms could be developed by using the OMPED as a potential OMP complex.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1546-1549
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• 2007

Chitosan oligosaccharide (COS, 3 kDa

• Journal of the Society of Cosmetic Scientists of Korea
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• v.21 no.2
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• pp.49-56
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• 1995

Chitosan microcapsules and microbeads were prepared by W/O emulsion method, and their morphologies were observed through SEM. The microcapsules have skin layer of 8 Um and 250 Um of mean diameter, The swelling test showed higher s welling ability in protic solvents than in aphotic solvents. After containing moth-yl violet in the microcapsules, the release patterns were investigated. The results sho wed that the addition of Iysozyme in pH 5.1 acetate buffer accelerated the re-lease rate. In case of the microbeads, the mean diameter was about 70 Um. The surface of the microbeads showed porous structures. The swelling ability of the beads revealed two times higher than the one of the microcapsules.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.321-322
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• 2003

Poly(vinyl alcohol) (PVA) is a polymeric biomaterial that obtained by the saponification of poly(vinyl acetate) (PVAc). It has a nontoxic and water-soluble synthetic polymer, and has excellent biodegradability, biocompatibility, ability of film forming, and hydrophilic property, which is widely used in biochemical and biomedical applications.$\^$1)/ Chitosan is one of a few natural cationic polysaccharides that can be obtaiend by alkaline deacetylation of chitin which is the second most abundant polymeric material in the earth.$\^$2)/ (omitted)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.83-87
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• 1999

Immobilization of amyloglucosidase (AMG) with chitosan microbead and its possible applications were evaluated. The diameter of chitosan inicrobead was about 1.2 mm and the optimum enzyme concentration for immobilization was 6 mg/ml. The relative activity of the immobilized enzyme was $97.8\%$ at pH 4.2 and $55^{\circ}C$ and the optimum condition for the immobilized enwme was the same to that of free enzyme. In case of temperature above $30^{\circ}C$, the activity of the immobilized enzyme was a little higher than that of free enzyme. The enzyme activities of both free and immobilized were stable for 6 months when stored at $35^{\circ}C$. The optimum temperatures of both enzymes for saccharification of the dextrinized starch were $55^{\circ}C$ while the relative activity of the immobilized enzlme was $62.6\%$.

• Journal of Chitin and Chitosan
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• v.23 no.4
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• pp.277-284
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• 2018

In this study, we investigated the anti-allergic effect of the ethyl acetate fraction of Ecklonia cava (EC-EtoAc) on the immunoglobulin E (IgE)/bovine serum albumin (BSA)-mediated activation of bone marrow-derived cultured mast cells (BMCMCs). We revealed that the $62.5{\mu}g/ml$ of EC-fractions ($EC-CHCl_3$, EC-Hexane and EC-EtoAc) inhibited IgE/BSA-activated ${\beta}$-hexosaminidase release from BMCMCs without cytotoxicity. Especially, EC-EtoAc showed the higher ${\beta}$-hexosaminidase release than the others. Also, EC-EtoAc reduced the expression levels of cytokines such as interleukin (IL)-$1{\beta}$, IL-4, IL-5, IL-6, IL-10, IL-13, interferon (IFN)-${\gamma}$ and tumor necrosis factor (TNF)-${\alpha}$ and a chemokine, thymus- and activation-regulated chemokine (TARC), compared to the only IgE/BSA-treated BMCMCs. Furthermore, EC-EtoAc significantly prevented the binding of IgE to Fc epsilon receptor $(Fc{\varepsilon}R)I$ and reduced the $Fc{\varepsilon}RI$ expression on the sensitized BMCMCs. Taken together, these results suggest that E. cava may be the natural agent with beneficial potentials for the treatment of type I allergic diseases induced by mast cell activation.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.99-103
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• 2007

The antibacterial efficacy of 0.1% (w/v) chitosan solution against Staphylococcus intermedius isolated from a dog with superficial pyoderma was evaluated in vitro and in vivo. The exposure time for the 0.1% chitosan solutions at different pH to be able to eliminate the bacterial cells and the effect of pH of the solutions on antibacterial activity was tested at the same time in vitro. The antibacterial activity of chitosan was compared to other antibacterial agents including 2.5% benzoyl peroxide, 0.5% chlorhexidine acetate, 0.1% chitosan solution combined with 2.5% benzoyl peroxide and chitosan combined with 0.5% chlorhexidine using a modified detergent scrub quantitative technique in 10 adult mongrel dogs in vivo. They were able to eliminate a number of bacteria after the exposure time of 10 minutes at varying degrees according to the pH of the solutions. The antibacterial activity of chitosan was inversely affected by pH with higher activity at lower pH value. The 0.1% chitosan solution was also efficacious against Staphylococcus intermedius in vivo. The combinations of chitosan with benzoyl peroxide and with chlorhexidine were shown to exert higher activity when compared to those of chitosan alone and benzoyl peroxide or chlorhexidine alone. The 0.1% chitosan solution was considered to be efficacious against Staphylococcus intermedius isolated from a dog with superficial pyoderma in both in vivo and in vitro and have a potential for the clinical applications in the treatment or pyoderma in dogs.