• 대한핵의학회:학술대회논문집
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• 1972.11a
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• pp.68.2-68.2
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• 1972

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.1
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• pp.99-103
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• 2002

Geopungdodam-tang(GDT) have been used in oriental medicine for many centuries as a therapeutic agent of apoplexy. The mechanism of GDT on the cerebral blood flow is not known. The purpose of this Study was to investigate effects of GDT on the pial arterial diameter and action mechanism of GDT-induced increased regional cerebral blood flow(rCBF). The changes of regional cerebral blood f1ow(rCBF) was determinated by Laser-Doppler Flowmetry(LDF), and the changes of pial arterial diametet were determinated by video microscopy methods and video analyzer. The results were as follows ; 1. Pial arterial diameter was significantly increased by GDT in a dose-dependent manner. 2. Pretreatment with L-NNA significantly inhibited GDT induced increased rCBF. 3. Pretreatment with methylene blue significantly inhibited GDT induced increased rCBF. 4. Pretreatment with indomethacin inhibited GDT induced increased rCBF. These results suggest that GDT causes a diverse response of cerebral hemodynamics(rCBF and pial arterial diameter). The cerebral hemodynamics is also mediated by nitric oxide synthase, cyclic GMP(guanylyl cydase) and prostaglandin(cyclooxygenase).

• Journal of computational fluids engineering
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• v.16 no.2
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• pp.81-87
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• 2011

The importance of shear thinning non-Newtonian blood rheology on the hemodynamic characteristics of idealized cerebral saccular aneurysms were investigated by carrying out CFD simulations assuming two different non-Newtonian rheology models (Carreau and Ballyk models). To explore effects of vessel curvature, a straight and a curved vessel geometry were considered. The wall shear stress(WSS), relative residence time(RRT) and velocity distribution were compared at the different phases of cardiac cycle. As expected, blood entered the aneurysm at the distal neck and created large vortex in both aneurysms, but with higher momentum on the curved vessel. Hemodynamic characteristics such as WSS, and RRT exhibited only minor effects by choice of different rheological models although Ballyk model produced relatively higher effects. We conclude that the assumption of Newtonian fluid is reasonable for studies aimed at quantifying the hemodynamic characteristics, in particular, WSS-based parameters, considering the current accuracy level of medical image of cerebral aneurysm.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1083-1088
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• 2004

This Study was designed to investigate the mechanism of Prescription for Treatment Abundant Expectoration due to Deficiency of Qi(Yukgunja-Tang, YGT) on cerebral hemodynamics [regional cerebral blood f1ow(rCBF) and pial arterial diameter(PAD)] in cerebral ischemia rats. The results were as follows: Both rCBF and PAD were significantly and stably decreased by YGT (10㎎/㎏, i.p.) during the period of cerebral reperfusion, which contrasted with the findings of rapid and marked increase in Control group. Pretreatment with indomethacin(1㎎/㎏, i.p.), an inhibitor of cyclooxygenase and methylene blue(10㎍/㎏, i.p.), an inhibitor of guanylate cyclase significantly but unstably increased the YGT-induced increases in rCBF during the period of cerebral reperfusion. Pretreatment with indomethacin significantly and stably decreased the YGT-induced increases in PAD during the period of cerebral reperfusion, but pretreatment with methylene blue increased unstably the YGT-induced increases in PAD during the period of cerebral reperfusion. In conclusion, the present authors thought that mechanism of YGT on cerebral hemodynamics was connected with guanylate cyclase in cerebral ischemia rats.

• The Journal of Internal Korean Medicine
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• v.26 no.3
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• pp.596-604
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• 2005

Objectives : Geopungjeseub-tang(Gufengchushi-tang) has been used in oriental medicine for many centuries as a therapeutic agent for hemiplegia caused by deficiency of qi(氣虛) and damp phlegm(濕痰). This study was performed to evaluate effects of Geopungjeseub-tang extract(GJT) on hemodynamics[regional cerebral blood flow(rCBF), pial arterial diameter(PAD), mean arterial blood pressure(MABP), heart rate(HR)] in normal rats and in rats with cerebral ischemia by middle cerebral artery(MCA) occlusion. Also, effects of adrenergic ${\beta}-receptor$, cyclooxygenase on response to GJT were evaluated. Methods : Laser-doppler flowmetry(LDF) measured changes of rCBF, MABP and HR. Video microscope and width analyzer measured changes in PAD. Results : rCBF and PAD increased after treatment with GJT(10mg/kg, i.v.) during the period of cerebral reperfusion, and pretreatment with indomethacin raised rCBF and PAD increased after treatment with GJT during the same period as above. Pretreatment with propranolol decreased rCBF, but increased after GJT treatment, but raised PAD increased after GJT treatment during this period of reperfusion. Conclusion : CR caused diverse responses were observed in rCBF and PAD after treatment with GJT. ACF action is mediated by adrenergic ${\beta}-receptor$ and cyclooxygenase. Result suggest that GJT has an anti-ischemic effect through the improvement of cerebral hemodynamics and has theraputic potential for cerebral apoplexy.

• Toxicological Research
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• v.17
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• pp.117-125
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• 2001

Envenoming by Russells viper causes a broad spectrum of renal impairment. Renal failure is an important complication in patients bitten by Russells viper. Experimental work in animals and in vitro has elucidated pathophysiological mechanisms that contribute to life threatening complications and have suggested possibilities for therapeutic intervention. The evidence in experimental animals regarding mechanisms of venom action in relation to changes in either extrarenal or intrarenal factors is presented. The cardiovascular system and renal hemodynamics are affected by venom. Reductions of renal function including renal hemodynamics are associated directly with changes in general circulation during envenomation. Possible endogenous mechanisms for releasing the hormone inducing renal vasoconstriction after envenomation are evident. Hormonal factor such as the catecholamine, prostaglandin and renin angiotensin systems induce these changes. Direct nephrotoxicity of venom action is studied in the isolated per-fused kidney. Characteristic polarization of the cell membrane, changes of mitochondrial activity and Na-K ATPase in renal tubular cells are observed. Changes in renal function and the cardiovascular system are observed of ter envenomation and are reversed by the administration of Russells viper antivenom (purified equine immunoglobulin, $Fab_2$ fragment). The neutralizing effects are more efficient when the intravenous injection of antivenom is given within 30 min after the envenomation.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.3
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• pp.137-141
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• 2006

The systolic and diastolic pressures in anesthetized Sprague-Dawley male rats were greatly decreased after single-dose of Cd treatment without significant changes in heart rate. There was a fluid-shift into the third space and/or -loss through the kidney, since plasma $Na^+$ concentration and hematocrit ratio were significantly increased by acute Cd exposure. The present study showed that the sustained hypotensive effect of single-dose Cd on the cardiovascular system might have resulted from the systemic hypovolemia. Furthermore, renal excretion of electrolytes, including $Na^+$ and $K^+$, and urine flow rate were increased by Cd intoxication. Interestingly, the ratio of $Na^+/K^+$ excretion was increased and reached the maximum level 3 hours after Cd injection and returned to the normal level after 7 hours. Nevertheless, there was no difference in the regression analysis of $Na^+$ excretion and urine flow rate in both groups. Therefore, the increase in the urine volume seemed to enhance the excretion of $Na^+$. This study strongly suggest that the hypotensive effect of Cd is mediated by systemic $Na^+$ loss through the kidney and/or hypovolemia via fluid-shift.

• Journal of Mechanical Science and Technology
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• v.19 no.9
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• pp.1761-1772
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• 2005

In blood flow passing through the mechanical heart valve (MHV) and elastic blood vessel, hemolysis and platelet activation causing thrombus formation can be seen owing to the shear stress in the blood. Also, fracture and deformation of leaflets can be observed depending on the shape and material properties of the leaflets which is opened and closed in a cycle. Hence, comprehensive study is needed on the hemodynamics which is associated with the motion of leaflet and elastic blood vessel in terms of fluid-structure interaction. In this paper, a numerical analysis has been performed for a three-dimensional pulsatile blood flow associated with the elastic blood vessel and curved bileaflet for multiple cycles in light of fluid-structure interaction. From this analysis fluttering phenomenon and rebound of the leaflet have been observed and recirculation and regurgitation have been found in the flow fields of the blood. Also, the pressure distribution and the radial displacement of the elastic blood vessel have been obtained. The motion of the leaflet and flow fields of the blood have shown similar tendency compared with the previous experiments carried out in other studies. The present study can contribute to the design methodology for the curved bileaflet mechanical heart valve. Furthermore, the proposed fluid-structure interaction method will be effectively used in various fields where the interaction between fluid flow and structure are involved.

• Journal of computational fluids engineering
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• v.15 no.4
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• pp.1-8
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• 2010

This article describes the numerical investigation of turbulent blood flow in the stenosed artery bifurcation under periodic acceleration of the human body. Numerical analyses for turbulent blood flow were performed with different magnitude of periodic accelerations using a modified turbulence model which was considering drag reduction of non-Newtonian fluid. The blood was considered to be a non-Newtonian fluid which was based on the power-law viscosity. In order to validate the modified $k-{\varepsilon}$ model, numerical simulations were compared with the standard $k-{\varepsilon}$ model and the Malin's low Reynolds number turbulence model for power-law fluid. As results, the modified $k-{\varepsilon}$ model represents intermediate characteristics between laminar and standard $k-{\varepsilon}$ model, and the modified $k-{\varepsilon}$ model showed good agreements with Malin's verified power law model. Moreover, the computing time and computer resource of the modified $k-{\varepsilon}$ model were reduced about one third than low Reynolds number model including Malin's model.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1127-1133
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• 2002

Cheonghunhwadam-tang(CHT) have been used in oriental medicine for many centuries as a therapeutic agent of vertigo by wind, fire and phlegm. CHTGR was CHT adding Gastrodae Rhizoma. The effects of CHTGR on the regional cerebral blood flow(rCBF) and mean arterial blood pressure(MABP) is not known. A comparative Study of action-mechanism of CHT and CHTGR on the cerebral hemodynamics is not known too. Therefore, purpose of this Study was to investigate effects of CHT and CHTGR on the rCBF and MABP, compare action-mechanism of CHT and CHTGR on the rCBF and MABP. The changes of rCBF and BP was determinated by Laser-Doppler Flowmetry(LDF). The results were as follows ; CHT extract was increased rCBF in a dose-dependent, but was not changed MABP compared with CHT non-treated group. CHTGR extract was decreased rCBF and MABP compared with CHTGR non-treated group in a dose-dependent. Action of CHT is not related with adrenergic β-receptor, cyclooxygenase and guanylate cyclase, but action of CHTGR is related with guanylate cyclase.