• Korea-Australia Rheology Journal
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• v.21 no.2
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• pp.127-133
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• 2009

Hemorheological results may be influenced by the time between blood sampling and measurement, and storage conditions (e.g., temperature, time) during sample delivery between laboratories may further affect the resulting data. This study examined possible hemorheological alterations subsequent to storage of rat and dog blood at room temperature ($22^{\circ}C$) or with cooling ($4{\sim}10^{\circ}C$) for 2, 4, 6, 24, 48 and 72 hours. Measured hemorheological parameters included hematological indices, RBC aggregation and RBC deformability. Our results indicate that marked changes of RBC deformability and of RBC aggregation in whole blood can occur during storage, especially for samples stored at room temperature. The patterns of deformability and aggregation changes at room temperature are complex and species specific, whereas those for storage at the lower temperature range are much less complicated. For room temperature storage, it thus seems logical to suggest measuring rat and dog cell deformability within 6 hours; aggregation should be measured immediately for rat blood or within 6 hours for dog blood. Storage at lower temperatures allows measuring EI up to 72 hours after sampling, while aggregation must be measured immediately, or if willing to accept a constant decrease, over 24~72 hours.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.844-849
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• 2008

We present a novel cell deformability monitoring chip based on the digitally measured cell lysis rate which is dependent on the areal strain of the cell membrane. This method offers simple cell deformability monitoring by automated high-throughput testing system. We suggest the filter design considering the areal strain imposed on the cell membrane passing through the filter array having gradually increased orifice length. In the experiment using erythrocytes, we characterized the cell deformability in terms of average fracture areal strain which was $0.24{\pm}0.014\;and\;0.21{\pm}0.002$ for normal and chemically treated erythrocytes, respectively. We also verified that the areal strain of 0.15 effectively discriminates the deformability difference of normal and chemically treated erythrocytes, which can be applied to the clinical situation. We compared the lysis rates and their difference for the samples from different donors and found that the present chips can be commonly used without any calibration process. The experimental results demonstrate the simple structure and high performance of the present cell deformability monitoring chips, applicable to simple and cost-effective cell aging process monitoring.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1682-1686
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• 2004

A slit-flow apparatus with laser diffraction method has been developed with significant advances in ektacytometry design, operation and data analysis. In the slit-flow ektacytometry (or laser-diffractometry), the deformation of red blood cells subjected to continuously decreasing shear stress in slit flow is measured. A laser beam traverses a diluted blood suspension flowing through a slit and is diffracted by RBCs in the volume. The diffraction patterns are captured by a CCD-video camera, linked to a frame grabber integrated with a computer, while the differential pressure variation is measured by a pressure transducer. Both measurements of laser-diffraction image and pressure with respect to time enable to determine deformation index and the shear stress. The range of shear stress of 0 ${\sim}$ 35 Pa and measuring time is less than 2 min. When deforming under decreasing shear stress, RBCs change gradually from the prolate ellipsoid towards a circular biconcave morphology. The Deformation Index (DI) as a measure of RBC deformability is determined from an isointensity curve in the diffraction pattern using an ellipse-fitting program. The advantages of this design are simplicity, i.e., ease of operation and no moving parts, low cost, short operating time, and the disposable kit which is contacted with blood sample.

• Archives of Pharmacal Research
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• v.11 no.2
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• pp.149-154
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• 1988

Impaired erythrocyte deformability was considered to paly an important role in microcirculatory disturbances. We recently confirmed that the brazilin, the main active principle of Caesalpinia sappan, enhanced activity of erythrocyte deformability and reduced blood viscosity. In this study, we examined the effects of brazilin on three biochemical parameters (ATP, 2, 3-diphosphoglycerate, and calcium) which influenced erythrocyte deformability. Treatment with barzilin increased erythrocyte deformability and ATP concentrations in streptozotocin-induced diabetic rats. Concentrations of 2, 3-diphosphoglycerate and calcium in diabetic rats following brazilin administration were decreased significantly compared to those of diabetic control rats. The results suggest that brazilin have a potential effect to improve rheological abnormalities in diabetes.

• The Journal of Internal Korean Medicine
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• v.31 no.3
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• pp.578-585
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• 2010

Objectives : Coldness of hands and feet has been regarded to be associated with blood circulation. This study was performed to assess the correlation between erythrocyte deformability and coldness of hands and feet. Methods : 145 patients who had taken an erythrocyte deformability test were selected for this study among hospitalized patients within 4 weeks after their cerebral infarction at the Internal Medical Department at Kyunghee Oriental Medical Center from August 2008 to August 2009. We divided the selected patients into two groups, with and without of coldness of hands and feet groups. The two groups were compared on risk factors for atherosclerosis and examined for variables including erythrocyte deformability. Results : 1. On demographic variables of the patients, only body mass index was significantly lower in the coldness of hands and feet group than the control group. There was no significant difference of the rate of hypertension, diabetes mellitus, hyperlipidemia, ischemic heart disease, smoking, drinking and carotid artery stenosis between the two groups. 2. According to blood test, the coldness of hands and feet group showed significantly lower erythrocyte deformability index than the control group. 3. Body mass index and erythrocyte deformability index showed a close relationship with coldness of hands and feet in multivariate analysis. Conclusions : The correlation between the erythrocyte deformability and coldness of hands and feet in cerebral infarction patients were decreased erythrocyte deformability participated in the mechanism of coldness of hands and feet.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2791-2796
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• 2007

In their long journey through the cardiovascular circuit, erythrocytes are coerced to shape transform and assume different shapes on account of varying flow conditions in different blood vessels. The present work was aimed to visualize these erythrocyte shape transformations by an invitro microcirculatory model, and assess multi-shape erythrocyte deformability. The model uses an in-house fabricated, inexpensive disposable micro flow channel to mimic certain invivo conditions and a fast frame video microscopic system for imaging the shape changes in erythrocytes. Results show the multi-shape transformation of erythrocyte christened as discoidal shape, the asymmetrically deformed 'hat' and 'bullet-like' shapes, and the axially deformed 'slipper' and 'spindle-like' shapes. Specific erythrocyte showed the shape transition and transformation while passing through the observed window. The obtained erythrocyte shapes very analyzed for deformability index using image processing techniques that varied significantly (p <0.001) for different shapes as compared with the resting shape.

• Korea-Australia Rheology Journal
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• v.16 no.3
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• pp.141-146
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• 2004

Shear-induced damage of Red Blood Cell (RBC) is an imminent problem to be solved for the practical application of artificial organs in extra corporeal circulation, as it often happens and affects physiological homeostasis of a patient. To design and operate artificial organs in a safe mode, many investigations have been set up to correlate shear and shear-induced cell damage. Most studies were focused on hemolysis i.e. the extreme case, however, it is important as well to obtain a clear understanding of pre-hemolytic mechanical damage. In this study, the change in deformability of RBC was measured by ektacytometry to investigate the damage of RBC caused by shear. To a small magnitude of pre-shear, there is little difference, but to a large magnitude of pre-shear, cell damage occurs and the effect of shear becomes significant depending on both the magnitude and imposed time of shearing. The threshold stress for cell damage was found to be approximately 30 Pa, which is much less than the threshold of mechanical hemolysis but is large enough to occur in vitro as in the extra corporeal circulation during open-heart surgery or artificial heart. In conclusion, it was found and suggested that the decrease of deformability can be used as an early indication of cell damage, in contrast to measuring plasma hemoglobin. As cell damage always occurs during flow in artificial organs, the results as well as the approach adopted here will be helpful in the design and operation of artificial organs.

• The Journal of Korean Medicine
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• v.44 no.4
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• pp.87-103
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• 2023

Backgrounds and objectives: Cardiotonic Pills^® (CP) are used for vascular diseases such as coronary diseases, atherosclerosis, and cerebral infarction. This study aimed to determine the transient effects of CP on cerebrovascular CO₂ reactivity (CVR) and erythrocyte deformability in normal subjects. Methods: This study had a crossover design and included 10 participants who were randomly allocated to 2 groups. The experimental group was given CP with water, while the control group was given only water. CVR was measured by hyperventilation-induced CVR of the middle cerebral artery (MCA) using transcranial Doppler (TCD). Erythrocyte deformability was measured using a Rheoscan-D microfluidic ektacytometer. All measurements were performed prior to and 1, 2, and 3 hours after CP or water administration. Blood pressure and heart rate were also measured before and after administration. Results: CP significantly improved CVR 3 hours after administration in the experimental group compared to the control group (p = 0.042). The corrected blood flow velocity at partial pressure of end-tidal carbon dioxide (PETCO₂) = 40mmHg (CV40) was also significantly improved 2 and 3 hours after administration in the CP group compared to the control group (p = 0.036 and p = 0.021, respectively). CP significantly improved erythrocyte deformability 3 hours after administration in the experimental group compared to the control group (p = 0.027). Mean heart rate and mean blood pressure showed no change. Conclusions: This study demonstrated that CP increases CVR and erythrocyte deformability. These results suggested that CP improves cerebral microcirculation which provide evidence for the future use of CP for prevention of ischemic stroke and neurodegenerative diseases.

• 순환기질환의공학회:학술대회논문집
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• 2004.11a
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• pp.52-53
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• 2004

• 순환기질환의공학회:학술대회논문집
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• 2003.11a
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• pp.42-43
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• 2003