• Journal of Pharmaceutical Investigation
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• 제27권1호
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• pp.57-64
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• 1997

$Amino-{\beta}-lactam$ antibiotics are absorbed by the dipeptide transporter in the small intestine. These uptakes are coupled to a proton influx. The inward proton gradient is partly induced by the $Na^+/H^+$ exchanger and calcium ion is involved in control of this antiport. Interaction between ampicillin which is one of the $Amino-{\beta}-lactam$ antibiotics and nifedipine which is one of calcium channel blocking agents was studied in rats in vivo and with rabbit jejunum mounted on the Sweetana/Grass diffusion cells in vitro. Bioavailability of ampicillin was increased significantly when nifedipine was co-administered orally in rats. There were no differences in the distribution phase and the elimination phase when ampicillin was given either alone or with nifedipine intravenously. Conditions for in vitro experiments were determined. The lift rate of $O_2/CO_2$ gas was controlled to 3 bubbles/sec and ampicillin was stable in the Kreb's buffer at pH 6.0. Absorption of ampicillin was the greatest when the completely-stripped serosal membrane was used. Transport of ampicillin from mucosal to serosal side in the rabbit jejunum was enhanced by 32% in the presence of nifedipine (p=0.059). Above results suggest that nifedipine might increase the plasma level of ampicillin via the improved absorption in the intestine rather than the reduction in the elimination or/and alteration in the distribution.

• 분석과학
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• 제11권4호
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• pp.266-270
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• 1998

활성탄의 특성을 이용하여 상업적으로 문제시되고 있는 수질 및 공기 정화용 항균성 Ag-활성탄을 제조하여 질소 흡착 특성, 표면구조 및 박테리아 저항성에 대하여 조사하였다. 높은 비표면적을 가진 활성탄에 대하여 $AgNO_3$을 사용하여 Ag-활성탄을 제조하였다. $AgNO_3$ 몰농도에 따라 침적된 Ag-활성탄의 비표면적 값은 $740-1112.2m^2/g$의 범위에 분포하고 있었으며, $AgNO_3$ 몰농도가 증가함에 따라 비표면적이 작아지는 경향을 나타내어 흡착된 Ag가 원료 활성탄의 표면구조에 영향을 주었다. SEM결과에 의하면, Ag 함침에 따라 흡착제의 외부 표면에 미세 동공에서 윈도우 블럭킹 효과를 나타내었다. 항균 실험을 위하여 박테리아로서 대장균(colon bacillus)의 일종인 Escherichia coli를 사용하였으며, Ag가 흡착되지 않은 활성탄의 경우에 있어서는 활성을 전혀 나타내지 않았으며, 흡착된 Ag의 양이 증가됨에 따라 활성의 범위가 증가함을 알 수 있었다.

• 대한약리학회지
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• 제8권2호
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• pp.35-39
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• 1972

Previous studies on the effect of the visible lights on the organism have shown the possible influences on the nervous system. It was reported that the illumination of blue beam increased the sympathetic tone and that of red beam increased the parasympathetic tone. The pharmacological actions of the sympathomimetics were also known to be altered by various visible lights. But their modes and mechanisms of actions on the nervous system have not been clarified and is obscure. To elucidate the precise mechanism of action of the visible lights on the nervous system, present study was made to observe the survival time of the mole living in the dark environment, under the illumination of the various visible lights and influences of several drugs. The results are summerized as follows: 1. The illumination of the natural sun light caused the survival time of the mole to be shortened and visible monochromatic beams (red, blue and green) even more markedly shortened the survival time. No significant difference was noted depending on the wave length of the chromatic beam. 2. The shortened survival time caused by the visible monochromatic lights was prolonged by strychnine but not affected by morphine. 3. The survival time under the illumination of the visible monochromatic lights was prolonged by acetylcholine and physostigmine. 4. The shortened survival time under the illumination of the monochromatic visible lights was not affected by adrenaline but prolonged by priscoline. It is suggested that the shortened survival time of the mole by the illumination of the visible lights can be prolonged by the stimulation of central and parasympathetic nervous system and blocking of the sympathetic nervous system.

• The Korean Journal of Physiology and Pharmacology
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• 제13권4호
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• pp.327-335
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• 2009

The aim of this study was to determine whether losartan, an angiotensin II (Ang II) type 1 ($AT_1$) receptor could influence the CA release from the isolated perfused model of the rat adrenal medulla. Losartan (5${\sim}$50 ${\mu}$M) perfused into an adrenal vein for 90 min produced dose- and time-dependent inhibition of the CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM, a direct membrane depolarizer), DMPP (100 ${\mu}$M) and McN-A-343 (100 ${\mu}$M). Losartan failed to affect basal CA output. Furthermore, in adrenal glands loaded with losartan (15 ${\mu}$M) for 90 min, the CA secretory responses evoked by Bay-K-8644 (10 ${\mu}$M, an activator of L-type $Ca^{2+}$ channels), cyclopiazonic acid (10 ${\mu}$M, an inhibitor of cytoplasmic $Ca^{2+}$ -ATPase), veratridine (100 ${\mu}$M, an activator of $Na^+$ channels), and Ang II (100 nM) were markedly inhibited. However, at high concentrations (150${\sim}$300 ${\mu}$M), losartan rather enhanced the CA secretion evoked by ACh. Collectively, these experimental results suggest that losartan at low concentrations inhibits the CA secretion evoked by cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization from the rat adrenal medulla, but at high concentration it rather inhibits ACh-evoked CA secretion. It seems that losartan has a dual action, acting as both agonist and antagonist to nicotinic receptors of the rat adrenal medulla, which might be dependent on the concentration. It is also thought that this inhibitory effect of losartan may be mediated by blocking the influx of both $Na^+$ and $Ca^{2+}$ into the rat adrenomedullary chromaffin cells as well as by inhibiting the $Ca^{2+}$ release from the cytoplasmic calcium store, which is thought to be relevant to the $AT_1$ receptor blockade, in addition to its enhancement of the CA release.

• 한국콘텐츠학회논문지
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• 제9권7호
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• pp.37-44
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• 2009

디지털 워터마킹은 디지털 콘텐츠에 워터마크를 삽입함으로써 불법적인 복제를 방지하고, 지적재산권 및 저작권을 보호하며, 소유권을 주장할 수 있는 근거를 제시하는 기술이다. 일반적으로 워터마킹 기법에서는 워터마크를 삽입함으로써 데이터 왜곡과 품질 저하가 불가피하다는 단점이 있다. 이를 극복하기 위하여 원래 데이터를 변경하지 않는 제로-워터마킹 기법들이 최근 제시되고 있다. 이 논문에서는 VQ(Vector Quantization) 방식의 블록 효과를 줄이고, 압축 비율과 품질을 향상시킨 SMVQ(Side Match Vector Quantization) 방식에 대한 제로-워터마킹 체계인 CSMVQ(Chaotic SMVQ)를 제안한다. SMVQ 이미지 압축에서는 동일하게 두 이웃 블록의 접면 정보를 이용하기 위하여 좌측 상단에서 우측 하단으로 진행되므로, 임의의 순서로 블록을 선택하여 워터마크를 삽입할 수 없다. CSMVQ에서는 이전 에 부호화된 (1개에서 4개까지의) 이웃 블록들의 접면 정보를 동적으로 고려하여 부호화를 진행하므로, 무질서한 방식으로 워터마크가 삽입되도록 지원할 수 있다. 이 기법을 적용한 이미지의 품질이 SMVQ보다 우수하며, 샤프닝, 메디안 필터링 등을 이용한 공격에도 워터마크가 강인함을 보여준다.

• The Korean Journal of Physiology and Pharmacology
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• 제14권6호
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• pp.407-412
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• 2010

3-Deazaadenosine (DZA), a potent inhibitor of S-adenosylhomocysteine hydrolase, was previously proposed to induce intrinsic apoptosis in human leukemic cells. In the present study, we analyzed the mechanism underlying the DZA-induced intrinsic apoptotic pathway. DZA activated typical caspase-dependent apoptosis in HL-60 cells, as demonstrated by an accumulation of hypo-diploidic cells, the processing of multiple procaspases and an inhibitory effect of z-VAD-Fmk on this cell death. During DZA-induced apoptosis, cytochrome c (cyt c) was released into the cytosol. This was neither prevented by z-VAD-Fmk and nor was it associated with the dissipation of mitochondrial membrane potential (${\Delta}{\Psi}_m$). Prior to the release of cyt c, BAX was translocated from the cytosol to mitochondria and underwent oligomerization. Finally, the overexpression of BCL-XL protected HL-60 cells from apoptosis by blocking both the cyt c release and BAX oligomerization. Collectively, these findings suggest that DZA may activate intrinsic apoptosis by stimulating BAX activation and thereby the release of cyt c.

• The Korean Journal of Physiology and Pharmacology
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• 제22권6호
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• pp.617-625
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• 2018

Neddylation is a post-translational protein modification process. MLN4924 is a newly discovered pharmaceutical neddylation inhibitor that suppresses cancer growth with several cancer types. In our study, we first investigated the effect of MLN4924 on colon cancer cells (HCT116 and HT29). MLN4924 significantly inhibited the neddylation of cullin-1 and colon cancer cell growth in a time and dose-dependent manner. MLN4924 induced G2/M cell cycle arrest and apoptosis in HCT116 and HT29 cells. Moreover, MLN4924 also triggered autophagy in HCT116 and HT29 cells via suppressing the PI3K/AKT/mTOR pathway. Inhibiting autophagy by autophagy inhibitor 3-MA or ATG5 knockdown reversed the function of MLN4924 in suppressing colon cancer cell growth and cell death. Interestingly, MLN4924 suppresses colon cell growth in a xenograft model. Together, our finding revealed that blocking neddylation is an attractive colon cancer therapy strategy, and autophagy might act as a novel anti-cancer mechanism for the treatment of colon cancer by MLN4924.

• Geomechanics and Engineering
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• 제14권5호
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• pp.467-477
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• 2018

Estimation of hydraulic parameters is a critical step during design of foundation dewatering works. When many piles are installed in an aquifer, estimation of the hydraulic conductivity should consider the blocking of groundwater seepage by the piles. Based on field observations during a dewatering project in Shanghai, hydraulic conductivities are back-calculated using a numerical model considering the actual position of each pile. However, it is difficult to apply the aforementioned model directly in field due to requirement to input each pile geometry into the model. To develop a simple numerical model and find the optimal hydraulic conductivity, three scenarios are examined, in which the soil mass containing the piles is considered to be a uniform porous media. In these three scenarios, different sub-regions with different hydraulic conductivities, based on either automatic inverted calculation, or on effective medium theory (EMT), are established. The results indicate that the error, in the case which determines the hydraulic conductivity based on EMT, is less than that determined in the automatic inversion case. With the application of EMT, only the hydraulic conductivity of the soil outside the pit should be inverted. The soil inside the pit with its piles is divided into sub-regions with different hydraulic conductivities, and the hydraulic conductivity is calculated according to the volume ratio of the piles. Thus, the use of EMT in numerical modelling makes it easier to consider the effect of piles installed in an aquifer.

• Journal of Yeungnam Medical Science
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• 제6권2호
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• pp.57-62
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• 1989

지연성 호흡저하의 위험성이 없으며 중추신경계에 작용하는 혈압강하제인 Clonidine을 경막외강으로 주입한 강우의 진통효과를 알아보고자 미추마취를 시행할 항문질환 환자 40명을 대상으로 I군(1.33% Lidocaine 15ml)과 II군(1.33% Lidocaine 15ml+Clonidine $75{\mu}g$.)으로 나누어 수술후 진통효과를 관찰해 보았던 바 다음과 같은 결론을 얻었다. 1. Lidocaine단독 주입한 I군에서는 평균 마취시간이 2.42시간이었다. 2. Clonidine $75{\mu}g$을 혼합 주입한 II군의 경우에는 평균 진통시간이 7.32시간이었다. 3. Clonidine을 혼합 주입한 미추마취경우에 진정제 정주로 환자가 수면상태로 된 후 심한 혈압강하 및 맥박감소가 있었으나 Clonidine의 효과인지 진정효과에 인한 변화인지는 알 수 없었으며 진정제를 투여하지 않은 경우에는 혈압강하 및 맥박 감소가 초래되지 않았다. 4. 수술후 Clonidine과 관련된 특별한 증상은 관찰되지 않았다. 이상의 결과로 보아 항문질환 수술후 특히 외래환자의 차원에서 술후 진통을 위한 방법으로는 지연성 호흡저하 및 뇨정체등의 부작용이 없는 Clonidine의 천골강내 투여방법이 바람직한 것으로 사료된다.

• Clinical and Experimental Pediatrics
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• 제59권1호
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• pp.8-15
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• 2016

Purpose: Nephrogenesis is normally accompanied by a tightly regulated and efficient vascularization. We investigated the effect of angiotensin II inhibition on angiogenesis in the developing rat kidney. Methods: Newborn rat pups were treated with enalapril (30 mg/kg/day) or vehicle (control) for 7 days after birth. Renal histological changes were checked using Hematoxylin & Eosin staining. We also investigated the intrarenal expression of vascular endothelial growth factor (VEGF)-A, VEGF receptor 1 (VEGFR1), VEGFR2, platelet-derived growth factor (PDGF)-B, and PDGF receptor-${\beta}$ with Western blotting and immunohistochemical staining at postnatal day 8. Expression of the endothelial cell marker CD31 was examined to determine glomerular and peritubular capillary density. Results: Enalapril-treated rat kidneys showed disrupted tubules and vessels when compared with the control rat kidneys. In the enalapril-treated group, intrarenal VEGF-A protein expression was significantly higher, whereas VEGFR1 protein expression was lower than that in the control group (P<0.05). The expression of VEGFR2, PDGF-B, and PDGF receptor-${\beta}$ was not different between the 2 groups. The increased capillary CD31 expression on the western blots of enalapril-treated rat kidneys indicated that the total endothelial cell protein level was increased, while the cortical capillary density, assessed using CD31 immunohistochemical staining, was decreased. Conclusion: Impaired VEGF-VEGFR signaling and altered capillary repair may play a role in the deterioration of the kidney vasculature after blocking of angiotensin II during renal development.