• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.293-297
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• 1993

Chitosan is a natural chelating agent. It is derived from chitin which is a cellulose-like biopolymer distributed widely in nature, expecially in shellfish, insects, fungi, and yeast. The purpose of the present study is to investigate whether orally given water soluble chitosan can eliminate intraperitoneally injected radiostrontium (Sr-85) in mice. Water soluble chitosan and usual food was mixed as 10:90 by weight. The mixed food were fed for 60 (group 1) or 90 days (group 2). No chitosan was given to the control group. Each group consists of 5 mice. Sr-85 ($0.2{\mu}Ci$) was intraperitoneally injected after completion of prefeeding of usual or mixed food. The same food was given for more 5 days. The animals were sacrificed at the 6th day. Isolated spines, skulls, femurs, tibias, teeth, and tails were counted by a gamma counter. The retention of Sr-85 in bones was significantly lowere in the prefeeding groups (p<0.01). It was lowest in the 90 day prefeeding group. Therefore, prefeeding of water-soluble chitosan was effective on the removal of intraperitoneally injected radiostrontium.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.45-48
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• 1998

카이토산(chitosan)은 항미생물성, 무독성, 인체적합성 및 양이온성 등의 특성을 지니며 항균, 방취, 보습, 생체적합성 및 생분해성 등의 다양한 기능을 나타내고 있는데, 이를 바탕으로 카이토산을 단독 또는 다른 천연섬유재료와 복합화시키는 연구가 행해지고 있다. 본 연구에서 선택한 카이토산과 복합체를 형성할 수 있는 성분인 견 피브로인(silk fibroin)은 17 종의 아미노산으로 이루어진 단백질로서 의류용 및 의료용 재료로서 이용되고 있는 고급섬유재료이다. (중략)

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.391-395
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• 1998

Purpose: Chitin and chitosan are nontoxic natural chelators that chelate radiostrontium effectively. The purpose of this study was to compare radiostrontium chelation of chitin and chitosan with that of well known chemical chelators, namely EDTA and DTPA. Materials and Methods: The chelaton rates of chitin, chitosan, EDTA and DTPA were compared using a column chromatography method (Sephadex G-25M, Sweden). Three kinds of chitins and four kinds of chitosans were used. All of them were water soluble. Results: Phosphated chitosan showed the highest chelation yield of 97% at pH 7. All of chitins, chitosans, EDTA and DTPA showed chelation yield of more than 90% independent of varing pH level. Conclusion: Chitin and chitosan have similar chelation rate as compared with EDTA and DTPA.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.9-14
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• 1997

Chitosan, a natural nontoxic chelator, was reported to reduce whole body retention of radiostrontium in mice. As calcium has a simillar chemical properties to strontium both of which be easily bound with hydroxyapatite structure, calcium can be either a competitor or enhancer to chitosan on the removal of radiostrontium. We compared the effect of chitosan and calcium on the excretion of ingested radiostrontium ($^{85}$Sr). Chitosan or calcium($Cacl_2$) and usual food was mixed as 1:99 by weight. The mixed food to chitosan (group 1) or calcium (group 2) were given orally for 30 days before $^{85}$Sr administration. In other groups, mixed calcium and chitosan solution (group 3), 1% calcium (group 4), or 1% chitosan solution (group 5) was given for 7 days immediately after oral administration of $^{85}SrC1_2$ ($0.25{\mu}Ci$). In control group, no chitosan or calcium were given. Either chitosan or calcium was effective on the removal of $^{85}Sr$ from mouse body(Table. 1). Addition of calcium on chitosan did not improve or deteriorate the effect of chitosan on the removal of $^{85}Sr$ from mouse body. In conclusion, calcium was similarly effective on the removal of $^{85}Sr$ from mouse body.

• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.222-229
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• 1994

Radiostrontium passes the placental barrier in pregnant rodents very well. Chitosan, a natural nontoxic chelator, was reported to reduce whole body retention of radiostrontium in mice. The aim of the present study was to evaluate water soluble chitosan as a blocking agent of transplacental transfer of radiostrontium in pregnant mice. Twenty pregnant mice were divided into four groups: control and three groups of chitosan treatment (groups 1 to 3). Sr-85(15KBq in 0.2ml saline) was subcutaneously injected into pregnant mice at the 17th day of pregnancy. In control mice, 0.2ml saline was given 5 hours after the injection of Sr-85. In group 1, 1% water soluble chitosan was given subcutanously for two days, twice daily after the injection of Sr-85. In group 2, 10% water soluble chitosan was given orally for 15 days before conception. In group 3, 0.3% water soluble chitosan was injected intravenously for 15 days, once daily before conception. Gamma counting of newborns were done at days 0, 2 and 7 after their births. Whole body retention of Sr-85 in newborns of control mice at days 0, 2, 7 were $3.1{\pm}0.3%,\;2.9{\pm}0.3%,\;2.8{\pm}0.3%$ respectively. In experimental groups, whole body retention of Sr-85 was significantly lower than that of control (p<0.01) and no statistical difference was noted between them. In group 1, the values were $2.1{\pm}0.3%,\;1.4{\pm}0.1%,\;1.4{\pm}0.1%$, respectively. In group 3, they were $2.1{\pm}0.2%,\;1.7{\pm}0.2%,\;1.6{\pm}0.2%$, respectively. In conclusion, the water soluble chitosan reduced transplacental contamination of radiostrontium in pregnant mice.

• Journal of Aquaculture
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• v.5 no.2
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• pp.177-182
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• 1992

Experiments were conducted with goldfish exposed to various levels of mercuric chloride(control group) and mercuric chloride with chitosan (experimental group). Dilutions of these two solutions were made in the concentration ranges 0.6 to 1.0 $mg/{\ell}$ and 1.2 to 2.0 $mg/{\ell}$, respectively. Fifty percent lethal concentration of mercuric chloride($LC_{50}$) for 48 hours with the species was between 0.6 and 0.7 $mg/{\ell}$. Exposure of goldfish to mercury produced a marked, dose-dependent mortality with elevation of concentration (P<0.05). However, at each concentration of mercuric chloride treated with chitosan, mortality decreased significantly compared to control group (P<0.05).

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.130-134
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• 1993

Radiostrontium is one of fallouts. It can be absorbed through intestine and causing radiation injury to bones. The purpose of this study is to evaluate the inhibitory effect of 10% chitosan (water soluble and insoluble) and 10% alginate (water soluble and insoluble) on radiostrontium adsorption. Water soluble and insoluble chitosans and alginates were given to 10 NIH male mice in each group for 7 days. At the 7th day, 74 MBq of $^{85}Sr$ were given through orogastric tube. Chitosans and alginates were given for additional 7 days. During the 7 days, radioactivities of feces were counted daily. Finally animals were sacrificed, and radioactivities of bones were counted. Fecal excretion was significantly higher in chitosan and alginate group as compared to control from the 1st day (p < 0.01). Water soluble chitosan group showed highest fecal excretion. Bony retention was significantly lower in the treated group than the control (p < 0.01). There was no difference among treated groups. In conclusion, both water soluble and insoluble chitosans and alginates were effective agents on lowering orally ingested radiostrontium ($^{85}Sr$).

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.123-129
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• 1993

Chitosan is known to be one of the natural chelating agents. It is derived from chitin which is a cellulose-like biopolymer distributed widely in nature, especially in shellfish, insects, fungi, and yeast. There are two forms of chitosans, water soluble and insoluble, The purpose of the present study is to investigate whether water soluble chitosan can be applied to reduce the bioabailability of radios-trontium in foods. We compared the effect of water soluble and insoluble chitosans on the absorption of ingested radiostrontium ($^{85}Sr$). Three percent water soluble and insoluble chitosan solutions were given orally, and immediately after $^{85}SrCl_2$ ($0.2{\mu}Ci$) was administered to rats using a orogastric tube. In one group water soluble chitosan solution was given for additional 4 days. And in control group no chitosan was given. Each group consisted of 6 rats. The whole-body retention of $^{85}Sr$, determined by in vivo counting method, was lower in water soluble chitosan group than that of water insoluble chitosan group and that of control. Urinary excretion of $^{85}Sr$ in chitosan-treated rats was higher than that of control. And 5 day ingested group of water soluble chitosan showed least whole body retention of $^{85}Sr$. In conclusion water soluble chitosan was more effective in reducing bioavailability of ingested radiostrontium in the gastrointestinal tract than insoluble chitosan.

• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.230-234
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• 1994

The aim of the present study was to elucidate the effect of the water soluble chitosans on the removal of contaminated radiostrontium (Sr-85) from the bone of mice. The remaining radioactivities in intravenously injected controls(group 1) were higher than in intraperitoneally injected controls (group 4, P<0.01). The % retention at day 5 were $57.7{\pm}1.9%,\;54.4{\pm}1.2%$, respectively. Single intravenous injection of 0.3% water soluble chitosan and continuous oral ingestion of 10% water soluble chitosan for 15 days were' ineffective on the removal of contaminated radiostrontiums. Multiple intravenous or intraperitoneal injections of water soluble chitosan effectively removed contaminated radiostrontiums(P<0.01 vs controls). In conclusion, water soluble chitosan might remove once incorporated radiostrontium from bones of mice. Further studies were needed to elucidate the mechanism of the removal.

• Journal of Radiation Protection and Research
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• v.22 no.4
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• pp.237-250
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• 1997

It has been reported that chitosan has little genetic toxicity as one of natural and nontoxic chelator and reduces the internal retention of radiostrontium in the mouse. This study is to examine that when water soluble chitosan is provided to the mouse on 17 days of pregnancy before and after radiostrontium contamination, how effectively it can inhibit an acute transfer of radiostrontium to fetus through placenta contaminated. Water soluble chitosan powder is mixed with general food for 60 days and 10%(Group 1) and 1%(Group 2) are provided respectively, and it is observed that the group with radiostrontium contamination on 17 days of pregnancy can inhibit more effectively the transfer of radiostrontium to fetus through placenta than control group with general food and the groups (Group 3, Group 4) with 10% and 1% of chitosan powder respectively after radiostrontium contamination (p<0.01, Table 1). It is found that when the pregnant mouse contaminated by radiostrontium on 17 days of pregnancy is prefed by chitosan, the transfer of radiostrontium to fetus through placenta can be inhibited.