• 동아시아식생활학회지
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• 제9권3호
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• pp.378-385
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• 1999

A reduced NaCl intake for the general population of the world has been recommended to reduce the overall blood pressure level and hence to reduce the overall incidence of cardiovascular disease. A high NaCl diet convincingly contributes to elevated arterial pressure in humans and animal models of hypertension. Among individuals there is considerable variability of blood pressure responsiveness to NaCl intake. In normotensive as well as hypertensive subjects, blood pressure can be judged to be salt sensitivity (SS) when observed to vary directly and substantially with the net intake of NaCl. The prevalence of SS in normotensive adults in the U.S. ranges from 15% to 42% and in hypertensive adults from 28% to 74%. SS is a risk factor for hypertension and may be an important marker in the identification of children for hypertension prevention programs. High NaCl intakes produce expansion of the extracellular fluid volume and thus increase blood pressure. Nonchloride salts of sodium does not expand the extracellular fluid volume and does not alter blood pressure. Blood pressure response to NaCl may be modified by other components of the diet. Low dietary intakes of potassium or calcium augment NaCl-induced increases of blood pressure. Conversely, high dietary intakes of potassium or calcium attenuate NaCl-induced hypertension. A greater intakes of potassium or calcium may prevent or delay the occurrence of hypertension. SS occurs when dietary potassium is even marginally deficient but is dose-dependently suppressed when dietary potassium is increased within its normal range. Orally administered KHCO$_3$, abundant in fruits and vegetates, but not KCl has a calcium-retaining effect which may contributed to its reversal of pressor effect of dietary NaCl. Since nutrients other than NaCl also affect blood pressure levels, a reduced NaCl intake should be only one component of a nutritional strategy to lower blood pressure.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제13권2호
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• pp.123-140
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• 2009

The effect of a solute concentration difference on the osmotic transport of water through the semi-permeable membrane of a simple cell model is investigated. So far, most studies on osmotic phenomena are described by simple diffusion-type equations ignoring all fluid motion or described by Stokes flow. In our work, as the governing equations, we consider the coupled full Navier-Stokes equations which describe the fluid motion and the full transport equation that takes into account of convection and diffusion effects. A two dimensional finite difference model has been developed to simulate the velocity field, concentration field, and semi-permeable membrane movement. It is shown that the cell swells to regions of lower solute concentration due to the uneven water flux through the semi-permeable membrane. The simulation is applied on a red blood cell geometry and the relevant results are presented.

• 대한의용생체공학회:의공학회지
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• 제33권3호
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• pp.114-127
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• 2012

Recent technical advancement allows noninvasive measurement of blood glucose. In this literature, we reviewed various noninvasive techniques for measuring glucose concentration. Optical or electrical methods have been investigated. Optical techniques include near-infrared spectroscopy, Raman spectroscopy, optical coherence technique, polarization, fluorescence, occlusion spectroscopy, and photoacoustic spectroscopy. Electrical methods include reverse iontophoresis, impedance spectroscopy, and electromagnetic sensing. Ultrasound, detection from breath, or fluid harvesting technique can be used to measure blood glucose level. Combination of various methods is also promising. Although there are many interesting and promising technologies and devices, there need further researches until a commercially available non-invasive glucometer is popular.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1869-1875
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• 2001

The paper presents computational and flow visualization results on a centrifugal blood pump. 4 impeller designs were tested at a rotational speed of 2000 rpm using blood analog as working fluid. All impellers have seven blades but of different geometry (Impellers A3, A4, B2 and R7). Flow visualization within the impeller passages was conducted using an image de-rotation system. A pair of large scale vortices was found within the blades of impeller R7 while a single vortex was found in most of the passages of backward facing impellers (Impellers A3, A4 and B2). To establish the effects of blade geometry on blood cells, CFD was used to simulate the blade to blade flow to provide an estimate of the maximum shear stress. The results showed that though most of the stresses within the blade passages are below a threshold level of 150 N/m$^2$for extensive erythrocyte damage to occur, there are some regions near to the leading edge of the pressure side where the shear stresses a abode threshold level.

• Asian-Australasian Journal of Animal Sciences
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• 제5권1호
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• pp.33-37
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• 1992

Napier grass (Pennisetum purpureum Schum.) harvested at an early growth stage was ensiled with 4% of molasses in a polyethylene bag silo which contained 15 kg of chopped forage each. Dry matter (DM) content of the silage was so low as 14.75%, although chemical quality of the silage was very high. Ratio of ammonia nitrogen to total nitrogen was 6.59%, and the pH value of the silage was 3.79. Nutritive value of the silage was estimated using goats and compared to that of a timothy hay as a reference ration. Feeding level of each rations was adjusted to a level of nitrogen (N) recommendation. DM and N digestibilities of the silage were 65.0 and 54.5%, respectively, but those of the timothy hay were 37.6 and 37.2%. Feeding of the napier grass silage maintained body weight and kept positive N retention. Ammonia N concentration in the rumen fluid in goats fed the napier grass silage increased after feeding, but blood urea concentration was constant. Feeding of the timothy hay did not increase ammonia N concentration in the rumen fluid, but increased blood urea concentration. These facts indicated that the napier grass silage had enough digestible DM and N for maintenance ration to goats.

• Journal of Chest Surgery
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• 제10권2호
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• pp.281-294
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• 1977

Superior vena cava to pulmonary arterial shunting operation was made between the superior vena cava and the right pulmonary artery in the fashion of end-to-end anastomosis in 20 mongrel dogs. The experimental animals were divided into three group and blood flow in the superior vena cava was occluded for 20, 30 and 60 minutes respectively, and observations were made for the changes in caval pressure and cerebrospinal fluid pressure. And pathologic examinations were also performed. On occluding the caval blood flow, the superior vena caval pressure was sharply and immediately elevated from $103.5{\pm}19.8mmH_2O$ at thoracotomy to $556.4{\pm}86.lmmH_2O$ within 2 minutes to make its plateau thereafter, and the cerebrospinal fluid pressure followed closely the changes of the superior vena caval pressure in its level and pattern being elevated from $102.0{\pm}19.9mmH_2O$ to $490.5{\pm}79.9mmH_2O$. The drops of both the caval and cerebrospinal fluid pressures were definite and marked on opening the shunt flow through the anastomosis, but these postoperative pressures retained still higher ones above their levels measured at thoracotomy. The pathological examinations of the brain and the spinal cord were also performed in six animals. Characteristic changes uniformly seen in all area and in all animals were the findings of capillary congestion and perivascular edema. On the other hand, ischemic nerve cell changes were rather evident, revealing their degrees and extents being related to the prolongation of the time of caval occlusion which has followed by the sustained high pressures in both the superior vena and the cerebrospinal fluid. The experiment suggests the safety of this surgical procedure with minimal, if any, permanent damage as long as the occlusion of the caval blood flow is not prolonged beyond the expected.

• 동의생리병리학회지
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• 제27권4호
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• pp.343-349
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• 2013

This article is a study on to which categories of modern diseases blood deficiency pattern types are assigned by reference to modern clinical papers. Clinical papers were searched in China National Knowledge Infrastructure(CNKI) from 1994 to 2013. Results are as follows. First, diverse diseases classified in qi-blood depletion pattern and pattern of blood deficiency and wind-dryness are reported and pattern types designated by the name of viscera are the minority. Second, among pattern types in Korean Standard Classification of Diseases(KCD), diseases classified in heart blood deficiency pattern, liver blood deficiency pattern and heart-liver blood deficiency pattern are a few. Third, the level of designation by the combined patterns such as qi deficiency, fluid deficiency, yin deficiency, kidney deficiency, essence deficiency, wind-cold, cold-dampness, dampness-heat, liver hyperactivity, liver depression and static blood is more specific than KCD, which makes pattern types more useful to clinical application. The detailed relation between modern diseases and pattern types can be an another topic.

• Journal of Chest Surgery
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• 제26권6호
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• pp.441-451
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• 1993

Protective effect of superoxide dismutase[SOD] and substrates on acute ischemic and reperfused myocardium was assessed by cardiac microdialysis. 30 Rabbits were divided into 4 groups; normal control group [group I, n=5], ischemic group [group II, n=5], SOD treated group [group III, n=10], and substrates treated group [group IV, n=10]. After a microdialysis apparatus was implanted in rabbit myocardium, coronary artery was occuluded for 5 minutes and reperfusion was performed for 30 minutes. Hemodynamic changes, CK-MB isoenzyme level and adenine ring compound level in effluent dialysates [equilibrated with interstitial fluid], and ultrastructural changes of myocardial cell were analysed. Systolic blood pressure at 10 and 30 minutes after reperfusion was higher in group III and IV than in group II [p<.05]. Also percent recovery of systolic blood pressure in group III [p<.01] and IV [p<.02] was higher than in group II. CK-MB isoenzyme level in effluent dialysates was peaked at 10 minutes after reperfusion, thereafter decreased in group II, III and IV. At 30 minutes after reperfusion, its level was lower in group III and IV than in group II[p<.05]. Adenine ring compound level in effluent dialysates increased till 10 minutes after reperfusion and progressively decreased. At 10 and 30 minutes after reperfusion, its level was lower in group III and IV than in group II without significance. Degree of myocardial damage was estimated by scoring of mitochondrial injury. Group I was within normal range and most severe injury was seen in group II. And the score of mitochondrial injury in group III and IV was lower than in group II. In conclusion, SOD and substrates[KMP solution] had protective effect on stunned myocardium. The microdialysis appratus was a good device for studying stunned myocardium, and cardiac microdialysis might be a unique technique for analysis of regional intramyocardial interstitial fluid.

• 한국전산유체공학회지
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• 제16권2호
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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.

• 대한수혈학회지
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• 제29권3호
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• pp.229-239
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• 2018

순환계는 혈액의 흐름이 원활하게 되도록 그 해부학적 구조와 혈류의 물리학적 특성이 연결되어있다. 혈액의 흐름에 영향을 주는 혈액의 물리학적 특성을 혈유변학적 인자(Hemorheologic factors)라 하며, 혈액의 점도(blood viscosity) 및 적혈구 응집도(erythrocyte aggregation)와 같은 혈유변학적 특성은 헤마토크리트(hematocrit; Hct)와 밀접한 관계를 가진다. 헤마토크리트가 높을수록 혈액 점도가 증가하고 적혈구 응집도는 증가하며 순환을 저해하고 조직에 산소 전달 능력을 방해한다. 혈청 페리틴은 과도하게 있을 경우 산화유리기(oxygen free radial)를 통하여 혈관 내피세포(vascular endothelial cell)와 혈구 세포(blood cell)에 산화 손상을 유발하여 심혈관계 손상을 유발한다. 이러한 기전을 근거로 사혈 혹은 헌혈을 심혈관계 질환의 예방 및 치료에 응용하려는 시도가 오랫동안 있었다. 사혈은 의학에 있어 오랜 역사를 가지면서 특히 한방의 치료적 개념으로 최근까지도 사용되고 있으나 그 과학적 근거가 불충분하고 아직까지 논란의 여지도 있어 근거 중심의 의학을 근간으로 하는 의학에서는 도외시되어왔다. 하지만 혈액량이 증가하면 혈유변학적 인자들(hemorheological factors) 역시 악화되면서 대 순환에서 동맥경화의 발생 및 진행에 영향을 주고, 모세순환(microcirculation)을 악화시키는 것으로 알려져 있으며 심뇌혈관 사건에 영향을 주는 것으로 보고되고 있다. 정기적인 헌혈자(regular blood donors)에게 혈유변학적 인자들을 저명하게 호전시키고 과도한 철분의 함량을 줄여서 산화유리기에 의한 혈구 및 내피세포의 산화 손상을 줄임으로써, 순환계내에서 혈액순환을 촉진시킬 수 있다는 증거들이 보고되고 있다. 헌혈의 효과가 심혈관계 질환에 이익이 된다는 확고한 장기적 코호트 연구결과가 도출된다면 절대적으로 헌혈 혈액량이 부족한 현실과 심혈관계 질환의 예후를 호전시킬 수 있다는 측면에서 중요한 역할을 할 수 있다고 생각된다.