• Journal of Chest Surgery
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• v.43 no.6
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• pp.565-575
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• 2010

Background: Various decellularization methods have been studied in order to develop tissue graft which is less immunogenic and more durable. This study was performed to investigate the physico-dynamic and histological effect of trypsin pretreatment on decellularization protocols. Material and Method: Two groups of bovine pericardium specimen each underwent decellularization process based on SDS and Triton X-100 or N-lauroylsarcosinate and Triton X-100. Two more groups additionally underwent pretreatment with 0.1% Trypsin/0.1% EDTA. After decellularization process, mechanical tensile strength was tested, then biomechanical test of permeability and compliance was tested before and after fatigue test. Light microscopy and electron microscopy was performed to observe histological findings. Result: There was no difference in mechanical tensile strength between groups, but permeability and compliance was decreased in trypsin pretreated groups. Light microscopic and electron microscopic findings revealed damage of the extracellular matrix in trypsin pretreated groups and in groups which underwent the fatigue test also. Conclusion: Trypsin pretreatment in decellularizing process of bovine pericardium damages extracellular matrix and increases permeability and compliance of the bovine pericardium, but did not decrease tensile strength. Further studies are needed to use enzymatic treatments in decellularization protocols.

• The Korean Journal of Pharmacology
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• v.28 no.1
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• pp.49-60
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• 1992

This study was designed to evaluate the responses of cardiovascular system to endothelin (ET) and neuropeptide Y (NPY) in 12 week-old SHR treated with or without enalapril (ENP) for 6 weeks. The diastolic blood pressure and heart rate were lower in ENP-treated SHR than in control. The pressor response to intravenous, but not intracerebroventricular, ET or NPY was attenuated by ENP treatment. The chronotropic action induced by electrical stimulation was attenuated by ENP or ET. The negative chronotropic action of ET was blocked by yohimbine. The increase in aortic tension induced by electrical field stimulation (EFS) was depressed in ENP-treated group as compared with non-treated group, and enhanced by ET, but not NPY, in the non-treated group. The ET-induced increase in tension was enhanced by removal of endothelium in the control group but not in ENP-treated group. The plasma concentration of norepinephrine and ET-induced increase in concentration of norepinephrine and epinephrine in plasma were decreased in ENP-treated group. These results suggest that preventive effect of enalapril on the development of hypertension may result from depressing vasoactive action of endothelin and neuropeptide Y, and sympathetic neurotransmission at peripheral nervous system.

• Journal of Yeungnam Medical Science
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• v.10 no.1
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• pp.144-156
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• 1993

This study was performed to investigate the effect of octreotide on the contractility of rat vas deferens. The smooth muscle strips isolated from the prostatic portion were myographied in isolated organ bath, Electric field stimulation (monophasic square wave, duration: 1 mSec, voltage : 50 V, frequency : 5 Hz or 30 Hz, train: 10 Sec) produced reproducible contraction. The contraction was composed of two component, first phasic component (FPC) and second tonic component (STC). These contractions were abolished by tetrodotoxin ($1{\mu}M$). Octreotide inhibited the field stimulation induced contractions both FPC and STC concentration-dependently. The FPC was decreased by a desentization of purinergic receptor by pretreatment of mATP, and the STC was decreased by pretreatment of reserpine(3 mg/kg, IP) 24 hours before experiments. Octreotide reduced the field stimulation induced contraction in the presence of mATP and of reserpinized muscle strips. The inhibitory effect of octreotide was more potent at 5 Hz than at 30 Hz. Octreotide did not affect basal ton and exogenous norepinephrine- or ATP-induced contraction. These results suggest that octreotide inhibit the contractility of the isolated rat vas deferens by inhibition of the release of neurotransmitters, both ATP and norepinephrine from adrenergic nerve terminal.

• Journal of Chest Surgery
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• v.31 no.2
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• pp.102-107
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• 1998

It has not been clear whether L-arginine plays solely a role contributing to vascular nitric oxide (NO) synthesis. To investigate the mechanisms by which L-arginine induces vasorelaxation, effects of L-arginine on the isometric tension, and tissue NOx and cyclic guanosine monophosphate(cGMP) contents were examined in the isolated rat thoracic aorta. L-Arginine induced a dose-dependent relaxation of aortic rings only with intact endothelium only. The vasorelaxation response to low concentrations of L-arginine was abolished by the pretreatment with NG-nitro-L-arginine methyl ester(L-NAME, 10-4 mol/L), whereas the relaxation caused by higher concentrations L-arginine(10-5-10-3 mol/L) was maintained and even more pronounced in the presence of L-NAME. L-Arginine did not affect the vascular tension precontracted with KCl. The vascular tissue contents of NOx/cGMP were not significantly affected by L-arginine, while they were decreased by L-NAME. L-Arginine could not completely recover the NOx/cGMP decreased by L-NAME. Methylene blue only partially antagonized the relaxation response to L-arginine. Indomethacin did not affect the L-arginine-induced vasorelaxation, whereas ouabain markedly attenuated the relaxation. It is suggested that L-arginine induces vasorelaxation not only through its contribution to NO synthesis, but also through enhancing another endothelium-dependent mechanism which is NO/cGMP-independent and cyclooxygenase- independent.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.83-91
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• 2006

Background : For unknown reasons, the serum ferritin concentrations are higher in patients with acute lung injury. A pretreatment with aspirin reduces the acute lung injury in rats subjected severe hemorrhage, and increases the rate of ferritin synthesis in vitro. This study investigated the effect of aspirin on the serum ferritin changes in rats subjected to severe hemorrhage. Methods : Hemorrhagic shock was induced by withdrawing blood (20 ml/kg of B.W.) through the femoral artery for 5 min. The rats were pretreated with aspirin (10 mg/kg, i.v.) 30 min before hemorrhage. Results : The protein content and leukocyte count in the bronchoalveolar lavage fluid, lung tissue myeloperoxidase activities were significantly higher after hemorrhage. The aspirin pretreatment prevented these changes. The serum and lavage fluid ferritin concentrations were elevated higher after hemorrhage. These were also attenuated by the aspirin pretreatment. Conclusion : The changes in the serum and lung lavage ferritin level might be closely related to the severity of hemorrhage-induced acute lung injury. Therefore, the serum and lavage ferritin concentrations can be a useful biomarker for patients with precipitating conditions.

• The Korean Journal of Pharmacology
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• v.20 no.2
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• pp.7-14
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• 1984

In pithed rats, rising in diastolic blood pressure by clonidine, when intravenously injected, is expressed as the postsynaptic action, and inhibitory action on electrical stimulation-induced tachycardia by clonidine is expressed as the presynaptic inhibitory action. In this study it was aimed to observe the inhibitory effect of imipramine caused by a single and chronic administration on both postsynaptic and presynaptic action of clonidine in pithed rats, and discussed in relation with the mechanism of antidepressant action of imipramine. 1) A rise of diastolic blood pressure by clonidine was not antagonized by prazosin, but by both phentolamine and piperoxan. 2) The inhibition by clonidine of tachycardia which was induced by electrical stimulation was also antagonized by phentolamine and piperoxan, but not by prazosin. 3) The increase in diastolic blood pressure in response to clonidine was inhibited by both a single or chronic administration with imipramine (20 mg/kg). It was more pronounced in the latter. 4) The inhibitory action of clonidine on the tachycardia was markedly inhibited by both types of administration with imipramine, between which there showed little difference. It is concluded that the presynaptic ${\alpha}_2-adrenoceptor$ is rather sensitively affected by a single administration with imipramine, and a long-term imipramine treatment may inhibit both pre- and postsynaptic ${\alpha}_2-adrenoceptors$, simultaneously. Furthermore, it was seemed unlikely that these results provide the evidence :to support the fact that the subsensitivity of presynaptic ${\alpha}_2-adrenoceptor$ may be the mechanism of action of tricyclic antidepressant.

• 기계와재료
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• v.23 no.4
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• pp.74-83
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• 2011

풍력발전기 동적 시뮬레이션 프로그램 개발을 위해 미국풍력기술연구센터(NWTC)의 프로그램군에 대해 분석하고 이를 소개하였다. 본 편에서는 에어포일 데이터를 생성하는 AirfoilPrep, IEC 61400-1 기준의 극한 조건에 해당하는 허브 높이의 바람 데이터를 생성하는 IECWind, 통계적인 방법에 의해 전 영역에 대한 난류 바람 데이터를 생성하는 TurbSim, 복합재료 블레이드의 구조적 특성치를 계산하는 PreComp, 블레이드와 타워의 모드 형상을 구하는 BModes와 같은 전처리기를 중심으로 설명하였다.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.8-13
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• 1998

Change of IgG production of feline mononuclear cell(MNC) was evalual vitro. MNC was treated with lipopolysaccharide(LPS) before cortisol administration. tisol induced change of B cell subpopulation with surface IgG and reduced IgG prods against virus. However, before treatment o$\ulcorner$ MNC with LPS induced increasement of subpopulation with surface IgG and IgG production against virus. These results impel: diminution of IgG production by cortisol is well again by LPS treatment.

• The Korean Journal of Pharmacology
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• v.10 no.1 s.15
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• pp.31-40
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• 1974

1. The authors investigated the effects of $PGE_1$ on the action of sympathomimetics in the vas deferens of guinea-pig, comparing with those in the rat vas deferens, and also the action of $PGE_1$ on the motility of nerve-free smooth muscle of chick amnion. 2. In the isolated guinea-pig vas deferens, the actions of phenylephrine and norepinephrine were much potentiated by pretreatment with $PGE_1$. Futher, in the isolated hypogastric nerve-vas deferens preparation of guinea-pig, effects of phenylephrine, norepinephrine and tyramine on the contractile response of vas to the hypogastric nerve stimulation and to the transmural stimulation were also augumented especially in tension by $PGE_1$-pretreatment. 3. In the isolated hypogastric nerve-vas preparation of rat, both contractile responses to hypogastric nerve and transmural stimulation were slowly reduced by treatment with $PGE_1$ and the potentiated effect of phenylephrine or norepinephrine was not observed in spite of pretreatment with $PGE_1$. 4. The actions of phenylephrine and norepinephrine on the denervated vas deferens of guinea-pig were also enhanced by $PGE_1$ as it were in the intact vas deferens, but there was no significant effect by $PGE_1$ on the action of norepinephrine in the denervated rat vas deferens. 5. $PGE_1$ in low concentration $(10^{-8}g/ml)$ did not affect the spontaneous motility of nerve-free smooth muscle of chick amnion ($9{\sim}11$ th day incubated chick), but in large concentration $(5{\times}10^{-8}g/ml)$ it caused irregular and slightly inhibitory movement. Pretreatment with $PGE_1$ on chick amnion did not exert any change on the action of phenylephrine applied. However, the stimulatory action of physostigmine on the chick amnion was a little antagonized by the low concentration of $PGE_1$. 6. It might be summarized that there is species difference between the actions of $PGE_1$ on the vas deferens of guinea-pig and that of rat, and the action of $PGE_1$ on the guinea-pig vas deferens might be mediated by the other mechanism rather than by direct action on the vas musculature.

• Journal of Yeungnam Medical Science
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• v.8 no.2
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• pp.84-94
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• 1991

The purpose of this study was to evaluate the influence of high does carbon tetrachloride($CCl_4$) on the hepatotoxic effect of dimethylnitrosamine(DMN) which induces acute hemorrhagic necrosis in liver. Rats were injected intraperitoneally DMN dissolved in physiologic saline by a dose of 40mg/kg. For changes related to $CCl_4$ pretreatment, rats were injected intraperitoneally $CCl_4$ dissolved in olive oil by a dose of 0.4mg/kg, and then injected DMN. The livers were extracted from the rats 3, 6, 12, 24, 48, 72, and 120 hours after $CCl_4$ and/or DMN injection. Liver tissues were examined with light and electron microscopes. The results were summarized as follows ; Light microscopic findings : Severe centrilobular hemorrhagic necrosis developed from 12 hours after injection of DMN and continued to 120 hours. On injection of DMN after $CCl_4$ pretreatment, Massive necrosis occurred early. But active regenerative changes were produced in 24 hours. In 120 hours, the liver recovered in almost normal appearance. The degree of necrosis in pretreated group was similar to that in DMN injection only, and the time of recovery was faster in preteated group. Electron microscopic findings ; The early change was mainly disorganization of RER in DMN injection, and clumping and vesicular dilatation of ER in injection of $CCl_4$. In pretreatment group the early change was similar in appearance with $CCl_4$ group, but severer in degree. According to the results, it was revealed that acute toxic effect of DMN was recovered more rapidly in pretreatment group. Thus it was suggested that $CCl_4$ had protective effect in DMN hepatotoxicity.