• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권5호
• /
• pp.326-331
• /
• 2001

With the aim of developing of pH-sensitive controlled drug release system, a poly(Llysine) (PLL) based cationic semi-interpenetrating polymer network (semi-IPN) has been synthesized. This cationic hydrogel was designed to swell at lower pH and de-swell at higher pH and therefore be applicable for achieving regulated drug release at a specific pH range. In addition to the pH sensitivity, this hydrogel was anticipated to interact with an ionic drug, providing another means to regulate the release rate of ionic drugs. This semi-IPN hydrogel was prepared using a free-radical polymerization method and by crosslinking of the polyethylene glycol (PEG)-methacrylate polymer through the PLL network. The two polymers were penetrated with each other via interpolymer complexation to yield the semi-IPN structures. The PLL hydrogel thus prepared showed dynamic swelling/de-swelling behavior in response to pH change, and such a behavior was influenced by both the concentrations of PLL and PEG-methacrylate. Drug release from this semi-IPN hydrogel was also investigated using a model protein drug, streptokinase. Streptokinase release was found to be dependent on its ionic interaction with the PLL backbones as well as on the swelling of the semi-IPN hydrogel. These results suggest that a PLL semi-IPN hydrogel could potentially be used as a drug delivery platform to modulate drug release by pH-sensitivity and ionic interaction.

• Bulletin of the Korean Chemical Society
• /
• 제33권11호
• /
• pp.3676-3680
• /
• 2012

An Epstein-Barr virus (EBV)-based plasmid contains the EBV nuclear antigen 1 (EBNA1) gene and EBV replication origin (oriP) sequence. Since EBNA1 (the only EBV-encoded protein) is combined with oriP, it is replicated simultaneously with chromosomal DNA in human, primate, and canine cells and is faithfully segregated at a stable copy number upon cell division. Consequently, it can be used to stably express gene inserts over a prolonged time in target cells. We have previously shown that the polyamidoamine (PAMAM) dendrimer can be surface-modified with L-arginine. Arginine is present at a high frequency in the transactivator of transcription (Tat) sequences of human immunodeficiency virus (HIV). It presents high membrane permeability and permits effective transfer of DNA inside the cells. In this study, we constructed two kinds of recombinant DNA by inserting the luciferase gene and enhanced green fluorescence protein (eGFP) gene as reporter genes into the pCEP4 plasmid vector. We measured dynamic light scattering (DLS) and zeta potential after preparing PAMAM-based cationic polymer/EBV-based plasmid complexes. We performed transfection of HEK 293 cell lines with the polyplexes, and monitored luciferase activity and green fluorescence protein (GFP) expression. Our results show that PAMAM-based cationic polymer/EBV plasmid complexes provide enhanced and sustained gene expression.

• 한국축산식품학회지
• /
• 제24권1호
• /
• pp.80-85
• /
• 2004

본 연구에서는 역미셀을 이용한 단백질 추출공정에서 적극적으로 활용되지 못했던 양이온 계면활성제에 의한 단백질 추출 가능성을 제시하였으며 초유로부터 IgG의 분리를 위한 반응조건을 조사하였다. IgG의 분리에 적합한 조건은 반응 수용액상의 경우 pH 8, 50 mM KCl었으며 유기용매상의 계면활성제(CDAB) 농도는 100 mM로 나타났다. 위의 조건에서는 초기시료에 존재하는 IgG의 90%이상이 회수되었으며 회수된 단백질의 93%가 IgG로 나타났다. 또한 본 연구는 기존의 역미셀을 이용한 일반적인 단백질 추출공정인 정추출 및 역추출 공정을 이용하지 않고 정추출 공정만을 이용함으로써 추출과정을 단순화하였다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제2권3호
• /
• pp.353-359
• /
• 1998

In gastrointestinal smooth muscle, muscarinic stimulation by carbachol (CCh) activates nonselective cation channel current ($I_{CCh}$) which is facilitated by intracellular [$Ca^{2+}$] increase. Caffeine is widely used in experiments to mobilize $Ca^{2+}$ from intracellular stores. This study shows a strong inhibitory effect of caffeine on $I_{CCh}$ in guinea-pig gastric myocyte. In this study, the underlying mechanism of the inhibitory effect of caffeine was investigated. $I_{CCh}$ was completely suppressed by the addition of caffeine (10 mM) to the superfusing solution. Inhibition of $I_{CCh}$ by caffeine was not related to the intracellular cAMP accumulation which was expected from the phosphodiesterase-inhibiting effect of caffeine. The blockade of $InsP_3-induced$ $Ca^{2+}$ release by heparin had no significant effects on the activation of $I_{CCh}$. When the same cationic current had been induced by intracellular dialysis of $GTP[{\gamma}S]$ in order to bypass the muscarinic receptor, the inhibitory effect of caffeine was significantly attenuated. The results of this study indicate that both intracellular signalling pathways for $I_{CCh}$, proximal and distal to G-protein activation, are suppressed by caffeine. A major inhibition was observed at the proximal level.

• 대한의생명과학회지
• /
• 제10권3호
• /
• pp.187-194
• /
• 2004

A short peptide corresponding to the nuclear localization signal (NLS) of human immunodeficiency virus (HIV)-l Tat protein, Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg, was employed to improve the efficiency of cellular uptake of nucleic acids. The peptide was first mixed with a reporter plasmid and then with cationic liposomes to form a tripartite complex of DNA/peptide/liposomes (DPL). Transfection efficiency of the DPL complex was compared with that of the conventional DNA/liposomes (DL) complex. When the DPL complex was formed with various cationic liposomes, DOTAP/DOPE (DP) liposome exhibited superior transfection efficiency to other liposomes tested in vitro. With the inclusion of the peptide, the DPL complex showed much enhanced transfection in various cancer cell lines. Particularly, transfection of the DPL complex in serum increased cellular uptake of a transgene up to 2 fold when compared with that in a serum free condition. Further, when the DPL complex was infused through the ureteric route of a rat, transfection efficiency was shown to be better in reporter gene expression than that obtained with the DL complex. This study shows that the DPL complex that is easy to formulate can be employed for much enhanced cellular uptake of a trans gene.

• Archives of Pharmacal Research
• /
• 제9권2호
• /
• pp.111-114
• /
• 1986

Bretylium tosylate is a quaternary ammonium compound used for the treatment of ventricular fibrilation in humans. It is advantageous to other cationic compound in the study of biliary excretion in that negligible amount is bound to plasma protein and metabolite is not likely is to be formed. Some researchers reported that the formation of ion-pair complex caused to increase the lipothilicity of cationic compound. The partition of bretylium between water and organic phase was increased with the addition of sodium taurodeoxycholate. Also sensitive gas chromatographical assay procedure using flame ionization detector was studied. This procedure can detect as low as 0.1 mg/ml using 0.1 ml biological sample, but contamination by previous injection is the major problem of this method.

• KSBB Journal
• /
• 제5권3호
• /
• pp.215-221
• /
• 1990

양이온 계변활성제의 역미셀을 이용하여 단백질을 선택적으로 분리할 수 있는 분리조건을 밝히기 위해서 분자량과 등전점이 다른 여러 단백질의 용해에 미치는 pH, 이온 및 강도, 계면활성제의 종류 등 system para-meter 틀에 대해 연구 검토하였다. 등전점이 낮은 pepSIn 은 pH 5-7 이상에서, 등전점이 높은 ribotluclease-a 나 lisozym$\xi$은 pH 11-12 이상에서 용해되어 단백질이 계면 활성제의 (+)전하와 반대전하언 (-)를 띠는 등전점 이상의 pH영역에서 용해가 가능하였다. KCI을 이용하여 이온강도를 증가시킴에 따라 단백질의 용해 정도는 전반적으로 감소하였다. 친수성부분은 동일하나 소수성 무분이 다콘 양이온계면활성제 CTAB, DDAB, TOMAC 을 이용하여 역미셀제를 변화시켰을 때, 소수성 탄화수 소사슬이 3개 인 TOMAC(Wo=5) 이 탄화수소사슬이 1개인 CTAB(Wo=28)와 2개인 DDAB(Wo=7-12)에 비해 작은 역셀을 형성하여 낮은 용해 정도플 보였 다. 찬은 DDAB에 대해서도 유기용매의 종류에 따라 W Wo가 달랐는데 benzene(Wo=7)에 비하여 t$\xi$trachloro-ethylene (Wo= 12)이 보다 큰 역미젤을 형성하고 용해 능력도 높았다.

• Journal of Plant Biology
• /
• 제31권3호
• /
• pp.227-237
• /
• 1988

Effects of putrescine on senescence in detached leaves of Chinese cabbage (Brassica campestris L.) in the light were investigated. The putrescine as a potent antisenescence substane markedly inhibited chlorophyll and protein loss at the 10mM concentraton in the detached leaves during the dark incubation. In the light, however, putrescine showed the opposite effects to dark incubation. The chlorphyll loss by putrescine in the light was stopped with darktransfer, and inhibited competitively by a divalent cation Ca2+. In the light, putrescine reduced the protease activity. Putrescine, in the light, increased H2O2 content and reduced the activities of enzymes -superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6-involved in inhibiting the accumulation of free radicals. These results suggest that the effects of puterscine on chlorophyll and protein loss in detached leaves of Chinese cabbage in the light are related to the cationic nature of putrescine and the accumulation of free radicals.

• Rapid Communication in Photoscience
• /
• 제4권2호
• /
• pp.41-44
• /
• 2015

Biomolecular photo-damaging activity of a water-soluble cationic porphyrin was examined using human serum albumin (HSA), a water-soluble protein as a target biomolecule model by a fluorometry. Dichlorophosphorus(V) tetraphenylporphyrin ($Cl_2P(V)TPP$), was synthesized and used as a photosensitizer. This porphyrin could bind to HSA and cause the photosensitized oxidation of HSA through the singlet oxygen generation and the oxidative photo-induced electron transfer (ET). Near infrared emission spectroscopy demonstrated the photosensitized singlet oxygen generation by this porphyrin. Decrement of the fluorescence lifetime of $Cl_2P(V)TPP$ by HSA supported the ET mechanism. Furthermore, the estimated Gibb's energy indicated that the ET mechanism is possible in the terms of energy. Because oxygen concentration in cancer cell is relatively low, ET mechanism is considered to be advantageous for photosensitizer of photodynamic therapy.

• Tuberculosis and Respiratory Diseases
• /
• 제50권2호
• /
• pp.196-204
• /
• 2001

기관지 천식은 가역적인 기도수축과 기도과민성 및 기도 염증을 특정으로 하는 만성염증성 질환으로 이중 호산구는 기관지천식의 병태생리 기전 중에서 기관지점막 상피세포의 손상을 초래하여 궁국적으로 기도과민성을 초래하는 것으로 알려져 있다. 또한 천식환자의 혈액, 기관지 폐포세척액 및 기관지 점막내의 호산구 증가는 기관지 폐쇄정도 및 기도과민성과 연관성이 있다고 보고되고 있으며, 활성화된 호산구 수와 혈중 ECP는 유의한 상관관계를 보인다고 보고하고 있고, 기관지천식의 경과 판정에 유용한 지표로 제시되었으나, 정확한 임상적 유용성이 확립된 바는 없다. 이에 혈중 ECP 농도를 측정하여, 즉시형의 가역적인 기도확장반응과 기도과민성($PC_{20}$)과의 관계를 알아보고 말초혈액 호산구수와 비교하여 혈중 ECP의 유용성을 평가하고자 하였다. 기관지천식으로 진단되었던 환자 중 일초간 호기량의 에측치($FEV_1$ % p)가 80% 이하이었던 중등증 및 중증 천식환자 71명을 대상으로 하여, 말초혈액을 채취하여 호산구수와 총 IgE농도, ECP를 측정하였고, 기관지확장제에 대한 반응과 메타콜린 기관지 유발검사를 시행하였다. 기관지확장제에 대한 반응군과 비반응군간에 나이, 성별에 통계적 차이는 없었으며, 총 IgE, $FEV_1$/FVC(%), $FEV_1$(% to predictive value) 등에도 통계적 차이는 없었으며 호산구수도 두 군간의 유의한 차이를 보이지 않았다. 하지만 ECP농도는 통계적으로 반응군에서 유의하게 반응군에서 높았으며 $PC_{20}$은 반응군에서 의미있게 낮았다. 그리고 기관지 확장제의 반응 정도와 혈중 ECP농도 및 기도과민성과의 관계에서 혈중 ECP 농도는 순 상관관계를 보였고 기도과민성($PC_{20}$)과는 역 상관관계를 보였다. 또한 혈중 ECP농도와 기도과민성과도 통계적으로 의미 있는 상관관계를 보였다. 이상의 결과로 혈중 ECP농도는 중등증 및 중증 기관지천식환자에서 급성 기도수축 정도와 기도과민성을 잘 반영하며, 천식의 치료와 임상경과 및 예후에 의미있는 지표로 이용될 수 있을 것으로 생각되며, 기관지 확장제의 반응성은 기관지의 염증과 연관될 것으로 생각된다. 또한 추후로 환자의 임상상과 천식의 정도 및 약물치료에 따른 ECP의 변화에 대한 연구가 필요할 것으로 생각된다.