• Polymer(Korea)
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• v.36 no.5
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• pp.617-621
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• 2012

PHEAs [${\alpha}$,${\beta}$-poly(2-hydroxyethyl-DL-aspartamides)], a class of poly(amino acid), have been widely studied as biodegradable and biocompatible polymers for potential biomedical and pharmaceutical applications. In this study, we investigated a homogeneous blend of PHEA with poly(N-vinyl pyrrolidone) (PNVP) and its semi-IPN (semi-interpenetrating polymer network) gels. Blend films were prepared by a solution casting method. The resulting blends were totally transparent over the whole composition ranges and the single $T_g$, changing monotonously with composition, was observed by DSC to confirm the miscibility between these two polymers. FTIR was used to discuss the possible hydrogen-bonding interaction between polymers. In addition, semi-IPN type gels were prepared by chemical crosslinking of PHEA/PNVP blend solution using hexamethylene diisocyanate (HMDI) as a crosslinking reagent. The prepared gel was characterized by their swelling property and morphology.

• Journal of Dairy Science and Biotechnology
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• v.32 no.1
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• pp.17-29
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• 2014

GRAS probiotics can be used to modulate intestinal microbiota and to alleviate various gastrointestinal disorders. In several recent studies, researchers have explored the potential expansion and usability of probiotics to reduce the risk factors associated with diseases, including obesity, hypercholesterolemia, arterial hypertension, hyperhomocysteinemia, and oxidative stress. In this review, our aim was to clarify the mechanism underlying interactions between hosts (animal or human) and probiotics and the beneficial effects of probiotics on human health.

• The Korean Journal of Nuclear Medicine
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• v.35 no.5
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• pp.334-341
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• 2001

Purpose: Ascorbic acid us known to act as an antioxidant. Therefore, it can be used in increasing the efficiency of radiochemical labeling of Technetium-99m setamibi by inhibition of oxidation of $Sn^{2+}$ at low concentration. We intended to estimate the efficiency of radiochemical labeling and the stability of the newly formed formulation when ascorbic acid was added to a commercial kit. Materials and Methods: Synthesis of sestamibi was performed according to Dong-A's patent procedure (No.10-2001-0012877). First, we undertook a study to evaluate the efficiency of radiochemical labeling of sestamibi containing ascorbic acid. The stability of the vials was assessed using either $7.5{\mu}g\;or\;75{\mu}g$ of ascorbic acid, added to commercial vials under the accelerated condition(Temp : $40^{\circ}C{\pm}2^{\circ}C$, Relative humidity : $75{\pm}5%$). Results: Sestamibi was synthesized in overall 35-40% yield over 5 steps from a commercially available methallyl chloride as a starling material. When ascorbic acid was added, the efficiency of radiochemical labeling was maintained compared to the vial with no ascorbic acid. The accelerated test showed that the addition of ascorbic acid inhibited the oxidation of $Sn^{2+}$ ion by antioxidation mechanism. Also, the efficiency of radiochemical labeling of this vial after 9 months was nearly the same as the starting point. Therefore, the storage period of the kit is likely to be extended. Taken together, it suggests that the addition of ascorbic acid as a stabilizer is desirable. Conclusion: To increase the stability of a sestamibi cold kit, it is desirable to add ascorbic acid as a stabilizer to the commercial formulation.

• The Korean Journal of Nuclear Medicine
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• v.36 no.4
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• pp.244-254
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• 2002

Purpose: This study investigated the differences between technetium-99m ethyl cysteinate dimer (Tc-99m ECD) and technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) uptake in the normal brain by means of statistical parametric mapping (SPM) analysis. Materials and Methods: We retrospectively analyzed age and sex matched 53 cases of normal brain SPECT. Thirty-two cases were obtained with Tc-99m ECD and 21 cases with Tc-99m HMPAO. There were no abnormal findings on brain MRIs. All of the SPECT images were spatially transformed to standard space, smoothed and globally normalized. The differences between the Tc-99m ECD and Tc-99m HMPAO SPECT images were statistically analyzed using statistical parametric mapping (SPM'99) software. The differences bgetween the two groups were considered significant ant a threshold of corrected P values less than 0.05. Results: SPM analysis revealed significantly different uptakes of Tc-99m ECD and Tc-99m HMPAO in the normal brains. On the Tc-99m ECD SPECT images, relatively higher uptake was observed in the frontal, parietal and occipital lobes, in the basal ganglia and thalamus, and in the superior region of the cerebellum. On the Tc-99m HMPAO SPECT images, relatively higher uptakes was observed in subcortical areas of the frontal region, temporal lobe, and posterior portion of inferior cerebellum. Conclusion: Uptake of Tc-99m ECD and Tc-99m HMPO in the normallooking brain was significantly different on SPM analysis. The selective use of Tc-99m ECD of Tc-99m HMPAO in brain SPECT imaging appears especially valuable for the interpretation of cerebral perfusion. Further investigation is necessary to determine which tracer is more accurate for diagnosing different clinical conditions.

• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.367-376
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• 2011

Early detection of carious lesions increases the possibility of treatment without the need for surgical intervention. Optical coherence tomography (OCT) is an emerging three-dimensional imaging technique that has been successfully used in other medical fields, such as ophthalmology for optical biopsy, and is a prospective candidate for early caries detection. The technique is based on low coherence interferometry and is advantageous in that it is non-invasive, does not use ionizing radiation, and can render threedimensional images. A brief history of the development of this technique and its principles are discussed in this paper. There have been numerous studies on caries detection, which were mostly in vitro or ex vivo experiments. Through these studies, the feasibility of OCT for caries detection was confirmed. However, further research should be performed, including in vivo studies of OCT applications, in order to prove the clinical usefulness of this technique. In addition, some technological problems must be resolved in the near future to allow for the use of OCT in everyday practice.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.180-189
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• 2004

Although the outcome of cancer patients after cytotoxic chemotherapy is related diverse mechanisms, multidrug resistance (MDR) for chemotherapeutic drugs due to cellular P-glycoprotein (Pgp) or multidrug-resistance associated protein (MRP) is most important factor in the chemotherapy failure to cancer. A large number of pharmacologic compounds, including verapamil, quinidine, tamoxifen, cyclosporin A and quinolone derivatives have been reported to overcome MDR. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are available for the detection of Pgp and MRP-mediated transporter. $^{99m}Tc$-MIBI and other $^{99m}Tc$-radiopharmaceuticals are substrates for Pgp and MRP, and have been used in clinical studies for tumor imaging, and to visualize blockade of PgP-mediated transport after modulation of Pgp pump. Colchicine, verapamil and daunorubicin labeled with $^{11}C$ have been evaluated for the quantification of Pgp-mediated transport with PET in vivo and reported to be feasible substrates with which to image Pgp function in tumors. Leukotrienes are specific substrates for MRP and $N-[^{11}C]acetyl-leukotriene$ E4 provides an opportunity to study MRP function non-invasively in vivo. SPECT and PET pharmaceuticals have successfully used to evaluate pharmacologic effects of MDR modulators. Imaging of MDR and reversal of MDR with bioluminescence in a living animal is also evaluated for future clinical trial. We have described recent advances in molecular imaging of MDR and reviewed recent publications regarding feasibility of SPECT and PET imaging to study the functionality of MDR transporters in vivo.

• Progress in Medical Physics
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• v.20 no.2
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• pp.80-87
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• 2009

Phase transformation, superelastic characteristics and variation of surface residual stress were studied for Nitinol shape memory alloy through application of UNSM technology, and life extension methods of stent were also studied by using elastic resilience and corrosion resistance. Nitinol wire of ${\phi}1.778$ mm showed similar surface roughness before and after UNSM treatment, but drawing traces and micro defects were all removed by UNSM treatment. It also changed the surface residual stress from tensile to compressive values, and XRD result showed less intensive austenite peak and clear martensite and additional R-phase peaks after UNSM treatment. Fatigue resistance could be greatly improved through removal of surface defects and rearrangement of surface residual stress from tensile to compressive state, and development of surface modification system to improve not only bio-compatability but also resistance to corrosion and wear will make it possible to develop vascular stent which can be used for circulating system diseases which run first cause of death of recent Koreans.

• The Korean Journal of Nuclear Medicine
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• v.4 no.1
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• pp.1-9
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• 1970

철대사(鐵代謝)에 관(關)한 연구(硏究)는 과거(過去) 30년(年)동안 새로운 검사방법(檢査方法)의 도입(導入)으로 눈부신 발전(發展)을이룩하였다. 1937년(年) Heilmeyer 등(等)에 의(依)하여 Ortho-phenanthrolin방법(方法)의 개발(開發)로 저색소성빈혈(低色素性貧血)의 원인(原因)이 구명(究明)되고 또한 이에 대(對)한 치료(治療)의 원칙(原則)이 세워졌다. 그 후 심(甚)한 감염(感染)이나 악성종양(惡性腫瘍)을 가진 환자(患者)者에서 관찰(觀察)되는 빈혈(貧血)에 대(對)해서 하나의 가설(假說)을 세워 이를 설명(說明)하려 하였는데 이는 곧 혈장(血漿)으로부터 철분(鐵分)이 신속(迅速)히 소실(消失)되어 망내계(網內系)나 병변(病變)이 있는 국소부위(局所部位)에 주(主)로 모여 들어 특수(特殊)한 방어기능(防禦機能)을 발휘(發揮)한다는것으로 연자(演者)는 방사성동위원소(放射性同位元素)를 이용(利用)하여 이 가설(假說)을 증명(證明)하였으며 이 연구(硏究)에는 또한 이문호교수(李文鎬敎授)가 Freiburg대학(大學) 유학중(留學中) 참여(參與)한 바 있다. 철대사(鐵代謝)를 파악(把握)하기 위(爲)해서 $^{59}Fe$가 흔히 사용(使用)되는데 이러한 방사성동위원소(放射性同位元素)를 이용(利用)함으로서 다음 사항(事項)들을 관찰(觀察)할 수 있었다. 즉(卽) 1. 소화장기(消化臟器)로 부터의 철흡수(鐵吸收) 2. 혈장(血漿)에서의 철(鐵)의 소실속도(消失速度) 3. 혈장내(血漿內)에서의 철교체율(鐵交替率) 4. 적혈구(赤血球)의 철이용(鐵利用) 5. 생체내(生體內)의 철분포(鐵分布) 6. 철배설(鐵排泄)의 정량적(定量的) 분석(分析) 또한 근년(近年)에는 특수(特殊)한 기능(機能)을 발휘(發揮)할 수 있는 동위원소(同位元素)를 이용(利用)하여 철흡수(鐵吸收) 및 대사이외(代謝以外)에도 적혈구(赤血球)의 수명(壽命)과 혈액량등(血液量等)을 측정(測定)하게 되었다. 경구적(經口的)으로 투여(投與)된 철(鐵)은 대부분(大部分) 십이지장(十二指腸)의 상부(上部)에서 흡수(吸收)되고 무기철(無機鐵)이 보다 쉽게 흡수(吸收)되어 가(價)의 상태(狀態)로 된다. 혈장(血漿)에서는 transferrin에 의(依)해서 철(鐵)이 운반(運搬)된다. 혈장철(血漿鐵)의 대부분(大部分)은 혈색소분해(血色素分解)에서 유래(由來)되며 이는 다시 혈색소(血色素)의 재생(再生)에 이용(利用)되는데 혈장내(血漿內) 철교체율(鐵交替率)은 방사성철(放射性鐵)을 이용(利用)하여 측정(測定)할수 있다 이와같이 방사성철(放射性鐵)을 이용(利用)하여 철대사과정(鐵代謝過程)을 숙지(熟知)함으르서 임상(臨床)에 응용(應用)하기에 이르렀으며 다음과 같은 질환(疾患)의 진단(診斷)에 특(特)히 큰 도움을 준다. A. 진성철결핍증(眞性鐵缺乏症) : 혁색소철(血色素鐵) 및 저장철(貯藏鐵)을 포함(包含)한 생체내(生體內) 전철분(全鐵分)의 부족(不足)된 상태(狀態)로서 실혈(朱血)에 의(依)한 것이 대부분(大部分)이다. 이 경우 철흡수(鐵吸收)는 증가(增加), 혈장철치(血漿鐵値)는 저하(低下), 철소실속도(鐵消失速度)는 증가(增加)되며 혈장철(血漿鐵) 교체율(交替率)은 항진(亢進) 혹(或)은 정상(正常)이다. B. 심(甚)한 염증성(炎症性) 질환(疾患) : 이 경우에도 혈장철치(血漿鐵値)의 저하(低下), 소실속도(消失速度)의 증가(增加), 교체율(交替率)은 정상(正常)보다 4배(倍)까지 증가(增加)할 수 있다. 골수(骨髓)에서 보다는 간(肝), 비(脾)와 같은 망내계(網內系)에 방사성철(放射性鐵)이 집결(集結)되는 것으로 보아 혈색소철(血色素鐵)보다는 저장철(貯藏鐵)이 관여(關與)되는 것이다. C. 원발성(原發性) 혈색소증(血色素症)(Idiopathic hemochromatosis) : 혈장철(血漿鐵)의 증가(增加)가 현저(顯著)하며 transferrin 농도(濃度)는 정상(正常)보다 낮으나 거의 대부분(大部分)의 철분(鐵分)으로 포화(飽和)된다. 철흡수(鐵吸收)는 증가(增加)되고 철소실속도(鐵消失速度)는 감소(減少) 되어 있으나 교체율(交替率)은 항진(亢進)되어 있다. 혈장철(血漿鐵)은 간(肝), 비(脾) 등(等)의 기관(器管)으로 저장집결(貯藏集結)되어 철저류(鐵貯溜)가 증대(增大)되므로 철이용증((鐵利用症)은 저하(低下)된다. D. 선천성(先天性) 무(無)$\ulcorner$트란스헤 린$\lrcorner$증(症)(Congenital atransferrinemia) : 방사성철(放射性鐵)을 이용(利用)한 진단방법(診斷方法)으로 Freiburg에서 7세(歲)의 소녀(少女)에서 발견(發見)한 증례(症例)인데 간(肝), 비(脾), 심(心)의 비대(肥大)가 임상적(臨床的)으로 인지(認知)되었고 중증(重症)의 철결핍상(鐵缺乏狀)을 검출(檢出)할 수 있었다. 철흡수율(鐵吸收率)의 상승(上昇), 혈장철치(血裝鐵値)의 감소(減少), 혈장철소실속도(血漿鐵消失速度)의 증가(增加), 혈장철교체율(血漿鐵交替率)의 상승(上昇) 및 적혈구(赤血球)에서의 철분이용율(鐵分利用率)의 저하(低下)를 ferrokinetic study에서 알 수 있었고 간(肝)에서 고도(高度)의 방사능(放射能)이 검출(檢出)되는 반면(反面), 비(脾)에서는 극소(極小), 골수(骨髓)에는 전(全)혀 방사능(放射能)이 들어가 있지 않았다. 이 증례(症例)와 같이 transferrin이 없으면 철분(鐵分)은 쉽게 조직(組織)으로 들어가 hemosiderin으로 저장(貯藏)되고 골수(骨髓)는 고도(高度)의 철결핍증(鐵缺乏症)을 나타내어 기관철침착증(器管鐵沈着症)과 철결핍성빈혈(鐵缺乏性貧血)이 동시(同時)에 나타나게 된다. 철대사장애면(鐵代謝障碍面)으로 보아 많은 미해결점(未解決點)이 남아 있으며 앞으로 자라나는 젊은 학도(學徒)들이 구명(究明)할 문제(間題)라고 믿는다.

• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.131-141
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• 2001

Purpose: We evaluated the sensitivity of the F-18 FDG PET by visual assessment and statistical parametric mapping (SPM) analysis for the localization of the epileptogenic zones in frontal lobe epilepsy. Materials and Methods: Twenty-four patients with frontal lobe epilepsy were examined. All patients exhibited improvements after surgical resection (Engel class I or II). Upon pathological examination, 18 patients revealed cortical dysplasia, 4 patients revealed tumor, and 2 patients revealed cortical scar. The hypometabolic lesions were found in F-18 FDG PET by visual assessment and SPM analysis. On SPM analysis, cutoff threshold was changed. Results: MRI showed structural lesions in 12 patients and normal results in the remaining 12. F-18 FDG PET correctly localized epileptogenic zones in 13 patients (54%) by visual assessment. Sensitivity of F-18 FDG PET in MR-negative patients (50%) was similar to that in MR-positive patients (67%). On SPM analysis, sensitivity decreased according to the decrease of p value. Using uncorrected p value of 0.05 as threshold, sensitivity of SPM analysis was 53%, which was not statistically different from that of visual assessment. Conclusion: F-18 FDG PET was sensitive in finding epileptogenic zones by revealing hypometabolic areas even in MR-negative patients with frontal lobe epilepsy as well as in MR-positive patients. SPM analysis showed comparable sensitivity to visual assessment and could be used as an aid in the diagnosis of epileptogenic zones in frontal lobe epilepsy.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.242-248
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• 2007

Purpose: To study the effect of recombinant human epidermal growth factor (rhEGF) on oral mucositis induced by cisplatin and radiotherapy in a mouse model. Materials and Methods: Twenty-four ICR mice were divided into three groups-the normal control group, the no rhEGF group (treatment with cisplatin and radiation) and the rhEGF group (treatment with cisplatin, radiation and rhEGF). A model of mucositis induced by cisplatin and radiotherapy was established by injecting mice with cisplatin (10 mg/kg) on day 1 and with radiation exposure (5 Gy/day) to the head and neck on days $1{\sim}5$. rhEGF was administered subcutaneously on days -1 to 0 (1 mg/kg/day) and on days 3 to 5 (1 mg/kg/day). Evaluation included body weight, oral intake, and histology. Results: For the comparison of the change of body weight between the rhEGF group and the no rhEGF group, a statistically significant difference was observed in the rhEGF group for the 5 days after day 3 of. the experiment. The rhEGF group and no rhEGF group had reduced food intake until day 5 of the experiment, and then the mice demonstrated increased food intake after day 13 of the of experiment. When the histological examination was conducted on day 7 after treatment with cisplatin and radiation, the rhEGF group showed a focal cellular reaction in the epidermal layer of the mucosa, while the no rhEGF group did not show inflammation of the oral mucosa. Conclusion: These findings suggest that rhEGF has a potential to reduce the oral mucositis burden in mice after treatment with cisplatin and radiation. The optimal dose, number and timing of the administration of rhEGF require further investigation.