• Journal of Pharmaceutical Investigation
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• 제25권3호
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• pp.249-264
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• 1995

Although liposome has many advantages as a pharmaceutical dosage form, its application in the industrial field has been limited because of some problems such as preparation method, reproducibility, scale-up, stability and sterilization etc. Liposomes prepared by microemulsification method had defined size, narrow size distribution, reproducibility and high entrapment efficiency. For enhancing the stability, the dry form of liposome was recommended. These types of liposome are proliposome and freeze-dried liposome. The liposome must have some properties for preparing of freeze-dried liposome; small size $(50{\sim}200\;nm)$, narrow size distribution and cryoprotectant. In this experiment, the liposomes containing 5-Fluorouracil(5-FU) and its prodrug(pentyl-5-FU-1-acetate; PFA, hexyl-5-FU-1-acetate; HFA) were made with soybean phosphatidylcholine, cholesterol, stearylamine(SA) and dicetyl phosphate(DCP) employing hydration method or microemulsification method using $Microfluidizer^{TM}$. Both or liposome types were MLV and MEL. After preparation, freeze drying and rehydration were performed. In the process of freezing, trehalose(Tr) was added as a cryoprotectant. Their evaluation methods were as follows; entrapment efficiency, mean particle size and size distribution, dissolution test, retain of entrapment efficiency and turbidity after freeze-drying. The results are summarized as belows. The entrapment efficiency of 5-FU was dependent on total lipid concentration and cholesterol content but that of PFA and HFA was decreased when cholesterol was added. When DCP and SA were added, entrapment efficiency was decreased. As the partition coefficient of drug was increased, entrapment efficiency was increased. Under the same condition, entrapment efficiency of MEL is similar to that of MLV. The mean particle size and size distribution of MEL were smaller than those of MLV. Dissolution rates of drug from both liposome types were comparatively similar. Dissolution rates of drugs with serum and liver homogenate were faster than without these material. After preparation of liposome, free drug was removed efficiency by Dowex 50W-X4. When liposome was freeze-dried and then rehydrated in the presence of Tr, characteristics of liposome were maintained well in MEL than MLV. Tr Was used successfully as a cryoprotectant in the process of freeze drying and the optimal ratio of Tr:Lipid was 4:1(g/g).

• 한국동물학회지
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• 제31권1호
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• pp.62-70
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• 1988

미토콘드리아가 포함하고있는 결정한유물의 미새구조와 면역황금표식법에 의한 분석을 위하여 우심근 세포의 미토콘드리아에서 전자전달체에 관여하는 효소를 분리하였다. 우심근 미토콘드리아에서 분리된 효소는 실험토끼에 주사하여 (복합체I,NADH-conezyme Q reductase; 복합체 III,Ubiquinol-cytochrome-c-oxldoreductase; 복합체 IV, Cytochrome-c-oxidase)들에 대한 면역항체를 얻었다. 이들 면역항체들은 우심근과 정상인의 골격근 미토콘드리아와 미토콘드리아에 결정함유물을 포함하는 mitochondrical myopathy환자의 골격근 미토콘드리아에 반응시켜 황금입자를 표식하고 전자현미경을 이용하여 이들 면역항체반응을 관찰하였다. 미토콘드리아가 포함하는 결정함유물의 미세구조에는 paracrystalline inclusions body와 multilamellar strudure inclusion body그리고 구형결정함유물(globular crystalline inclusions body) 및 윤형구조 (whirl shaped structure)의 크리스테 중심에 있는 구형결정함유물 등의 4종류로관찰되었다. 복합체 I,복합체 Iv의 효소에 대한 항체를 우심근과 정상인 골격근 그리고 mitochondrical myopathy환자의 골격근에 동일한 면역반응을 시켰을때 미토콘드리아 크리스테에 부착하는 황금입자의 표식 정도는 각각의 근조직에서 유사한 반응이 관찰되었다. 복합체 III의 효소에 대한 항체는 우심근과 정상인의 골격근에서는 유사한 반응이 나타났으나 mitochondrical myopathy환자의 골격근에서는 극히 소수의 황금입자가 관찰되었다. 구형결정함유물은 복합체 I,III,IV의 3종류의 효소에 대한 면역반응 결과 황금입자표식은 관찰되지 않았다. 따라서 mitochondrical myopathy환자의 미토콘드리아에는 복합에 III의 효소가 결핍되었으며 구형결정함유물은 전자전달체 효소들인 복합체 I,III,Iv 효소단백질과는 상관없는 물질로 생각된다.

• Applied Microscopy
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• 제16권2호
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• pp.49-60
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• 1986

Ultrastructures of the large and elongated cells (idioblasts) in the haustorium of a parasitic angiosperm, Cuscuta australis R. Brown growing on the host plant, Trifolium repens L. were investigated by the electron microscopy. The idioblasts were characterized by the presence of a large nucleus, small vacuoles, and dense cytoplasm including a number of various cell organelles such as ribosome, rough endoplasmic reticulum(r-ER), mitochondrion, dictyosome, proplastid, multilamellar structure(MLS), microfilament bundle(MFB), and cytosegresome. Therefore, it is suggested that the idioblasts are metabolical1y very active. Particularly, MLS, MFB, and cytosegresome observed in this study did not appear in the haustorial cells of the other parasitic angiosperms. MLS was transformed into vacuole and also incorporated with cell wall. MFB composed of microfilaments, about each 7.5 nm in diameter, was observed in nucleus and also cytoplasm. Some types of MFB were distinguished on the basis of arrangement of microfilaments. A part of cytoplasm sequestered by stacked cisternae of smooth ER(s-ER), cytosegresome, was altered into a vacuole which was formed by digestion of the sequestered cytoplasm and of cisternae of s-ER. Cell organelles such as MLS, MFB, and cytosegresome were discussed in relation to the metabolic control of the idioblasts.

• Applied Microscopy
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• 제19권1호
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• pp.34-48
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• 1989

The oval shaped pericardial cells are clustered along the lateral sides of the heart and irregularly connected with the heart. The cells are bounded by a basement membrane. The basement membranes of the connected two peicardial cells are irregularly linked each other there-fore funnels are formed. The multiple invaginations of the cell membrane are observed and septate junctions develope at the part of enterance of the cell membrane. The coated pits are appeared in the inner side of the invaginated cell membrane. The coated vesicles, tubular and spherical shaped vesicle, Golgi complex containing high electron densed material in the cisternae and mitochondria are observed in the cytoplasm and lysosomes are remarkably well developed. The whirled membrane structures in the multiformed complex bounded by single membrane are linked with low electron densed granules and spherical shaped small granules having high electron density with $0.03{\mu}m$ in diameter are located between the whirled membrane in a row and gradually secretes the granules and then they produced the multilamellar body. The lysosomal regions of cytoplasm of pericardial cell are appeared negative reaction to the acid phosphatase and according to the results of the electrophoresis, lipoproteins having acid phosphatase activity are contained. The axon is contacted with the pericardial cells.

• Food Science and Biotechnology
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• 제14권5호
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• pp.604-607
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• 2005

In this study, the effect of ${\beta}$-sitosterol (SS) in the liposome bilayer on the stability of incorporated retinol was evaluated. Retinol was incorporated into liposomes consisting of various ratios of soybean phoaphatidylcholine (PC) to SS, while liposomes were prepared as multilamellar vesicles by the dehydration/rehydration method. Retinol was readily incorporated into liposomes with various SS contents, with incorporation efficiencies higher than 98% for all conditions. The incorporation efficiency of retinol increased slightly as the SS content in liposomes increased. Its average particle size also increased as the SS content increased. Mean particle size at PC to SS ratios of 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50 were 12.16, 17.57, 35.00, 40.62, 83.45, and $88.94\;{\mu}m$, respectively. Liposomal retinol degradation in aqueous solution was measured with respect to SS content at various periods of time at four different temperatures of 4, 25, 37, and $50^{\circ}C$, and the stability of the incorporated retinol enhanced as the SS content increased. At $4^{\circ}C$, for example, retinol in the liposomes of 50:50 (PC:SS) remained at 84.42% after storage for 10 days, while in 100:0 (PC/SS) it remained at 42.62%. These results indicate that SS content in liposomes played an important role in the incorporation efficiency of retinol and its stability.

• Journal of Plant Biology
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• 제36권3호
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• pp.285-292
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• 1993

Cellular compatibility in the self-parasitism of Cuscuta australis R. Brown was studied at the ultrastructural level. The front cells of the haustorium penetrated the host stems independently grew within the host tissues and transformed into elongate, filamentous hyphae. Each hyphal cells contained a large nucleus and dense cytoplasm with abundant cell organelles. Multilamellar structures were contained in the cytoplasm and cell walls of the penetrating hyphal cells. When the hyphal cells did not yet invade the host cells, the middle lamella and the fused cellulosic cell walls of the two partners at the host-parasite interface were preserved well. As the invasion of the parasitic hyphal cells progressed, however, the middle lamella was not found at the interface and the host cell walls and plasma membranes were partially broken down. A hyphal cell penetrated deeply into the host cell had a more darkly stained cytoplasm with numerous of cell organelles. In the host cells attacked by the hyphal cells the limiting membranes of plastids were broken down and several vesicles were arrayed near the cell walls. No plasmodesmatal connections between the host and parasite cell walls were found; however, half-plasmodesmata were observed frequently on the side of the hyphal cell walls. These results suggested that the compatibility response in the self-parasitism of Cuscuta was expressed by cell walls, not by plasmodesmata, between the host and the parasite cells.

• 대한화학회지
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• 제67권2호
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• pp.89-98
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• 2023

The cell membrane, also known as the biological membrane, surrounds every living cell. The main components of cell membranes are lipids and therefore called as lipid membranes. These membranes are mainly made up of a two-dimensional lipid bilayer along with integral and peripheral proteins. The complex nature of lipid membranes makes it difficult to study and hence artificial lipid membranes are prepared which mimic the original lipid membranes. These artificial lipid membranes are prepared from phospholipid vesicles (liposomes). The liposomes are formed when self-forming phospholipid bilayer comes in contact with water. Liposomes can be unilamellar or multilamellar vesicles which comprises of phospholipids that can be produced naturally or synthetically. The phospholipids are non-toxic, biodegradable and are readily produced on a large scale. These liposomes are mostly used in the drug delivery systems. This paper offers comprehensive literature with insights on developing basic understanding of lipid membranes from its structure, organization, and phase behavior to its potential use in biomedical applications. The progress in the field of artificial membrane models considering methods of preparation of liposomes for mimicking lipid membranes, interactions between the lipid membranes, and characterizing techniques such as UV-visible, FTIR, Calorimetry and X-ray diffraction are explained in a concise manner.

• Journal of Photoscience
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• 제9권2호
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• pp.451-453
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• 2002

A new concept of "photo" -antisense method has been evaluated, where the inhibition of gene expression by the conventional antisense method is enhanced by photochemical binding between antisense oligonucleotides conjugated with photo-reactive compound and target mRNA or DNA. Fluorescein labeled oligodeoxyribonucleotides (F-DNA) was delivered to cell nuclei in the encapsulated form in multilamellar lecithin liposomes with neutral charge. F-DNA was previously shown to photo-bind to the complementary stranded DNA, and the delivery system using neutral liposome to be effective in normal human keratinocytes. In the present study, we used human kidney cancer G401.2/6TG.1 cell line to be advantageous in reproducible experiments. p53 was adopted as a target gene since antisense sequence information has been accumulated. The nuclear localization ofF-DNA was identified by comparing the fluorescence ofF-DNA with that of Hoechst 33258 under fluorescence microscope. After 7hr incubation to accumulate p53 protein induced by UV -B, p53 protein was quantified by Western blot. After 2hrs from F-DNA application, about 30% of cell population incorporated F-DNA in their nuclei with some morphological change possibly due to liposomal toxicity. Irradiation of visible light longer than 400nm from solar simulator at this time enhanced the inhibitory action of antisense F-DNA. The present results suggest that photo-antisense method is promising to control gene expression in time and space dependent manner. Further improvement of F-DNA delivery to cancer cells in the stability and toxicity is in progress. progress.

• BMB Reports
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• 제35권4호
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• pp.358-363
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• 2002

Chemical and photochemical processes during storage and preparation rapidly degrade retinol, the most active form of vitamin A. therefore, the efficacy of incorporation into liposomes in order to modulate the kinetics of retinol degradation was investigated. Retinol was readily incorporated into multilamellar liposomes that were prepared form soybean phosphatidylcholine; the extent of the incorporation was 98.14±0.93% at pH 9.0 at a ratio of 0.01 : 1 (wt:wt) retinol : phospholipid. It was only marginally lower at higher retinol concentrations. The pH of the hydration buffer had a small effect. The incorporation efficiency ranged from 99.25±0.47% at pH 3 to 97.45±1.13% at pH 11. The time course of the retinol degradation in the aqueous solution in liposomes was compared to that of free retinol and free retinol with α-tocopherol under a variety of conditions of pH(3, 7, and 11), temperature(4, 25, 37, and 50℃), and light exposure(dark, visible, and UV). The retinol that was incorporated into the liposomes degraded significantly slower than the free retinol or retinol with α-tocopherol at pH 7 and 11. At pH 3, where the free retinol degrades rapidly, the degradation kinetics were similar in liposomes and the presence of α-tocopherol. At pH 7.0 and 4℃ in the light, for example, free aqueous retinol was completely degraded within 2 days, while only 20% of the retinol in the liposomes were degraded after 8 days. In general, the protective effect of the liposome incorporation was greater at low temperatures, at neutral and high pH, and in the dark. The results suggest that protection is greater in the solid, gel phase than in the fluid liquid crystalline phase lipids. These results indicate that the incorporation into liposomes can extend the shelf-life of retinol under a variety of conditions of temperature, pH, and ambient light conditions.

• 한국식품과학회지
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• 제40권1호
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• pp.115-117
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• 2008

리포솜은 인지질로 구성된 인위적 세포막으로서, 본 연구에서는 초음파와 압력을 이용하여 나노 리포솜을 제조하였다. 먼저 리포솜을 탈수/재수화법으로 제조하였다. 형성된 multilayer vesilces(MLV)의 크기는 $10{\mu}m$ 이상이었다. Tip-type의 초음파 처리기와 French press를 이용하여 리포솜의 크기를 감소시켰다. MLV에 대한 출력 112.5W, 10분간의 초음파 처리로 리포솜의 크기가 450 nm 이하로 감소되었다. 또한, 6,000 psi 이상의 압력에서는 100 nm 내외의 균일한 리포솜이 생성되었다. 초음파와 가압에 의한 리포솜 용액의 색도는 대체로 명도, 적색도, 황색도가증가하였으며, 육안으로는 점점 더 투명하게 되었다. 이러한 결과는 초음파와 French press를 이용한 가압 처리로 나노 크기의 리포솜을 얻을 수 있음을 의미한다.