Clinical Hemorheology and Microcirculation - Volume 36, issue 3

Authors: Saldanha, Carlota | Silva, Ana S. | Gonçalves, Sónia | Martins-Silva, João

Article Type: Research Article

Abstract: The objective of the present work was to study the effects of erythrocyte proteins phosphorylation in erythrocyte aggregation and deformability. Human whole blood samples were incubated in vitro in absent and in presence of the phosphorylation/dephosphorilation band 3 inhibitors and also with adenylyl cyclase, guanylate cyclase and PI3K inhibitors and the erythrocyte aggregation index (AIE) and deformability were assayed. The results show that when band 3 is phosphorylated in presence of a PTP inhibitor an increase in erythrocyte aggregation index is observed (p<0.0001). A partial dephosphorylation band 3 state, induced by PTK inhibitors, show a decrease in the erythrocyte aggregation …index (p<0.002). However both manipulated states induced lower EAI values than blood samples aliquots controls. The guanylate cyclase and PI3-K inhibitors significantly decrease the erythrocyte aggregation index in relation with the control blood samples. Erythrocyte deformability in presence of all the inhibitors did not showed significant changes. PTP and PI3-K inhibitors showed a significantly increase in the plasma potassium concentrations not associated with EAI values. Methehemoglobin levels were increased significantly when guanylate cyclase inhibitor is present in the blood samples. In conclusion, the results suggest that erythrocyte aggregation index is dependent of the phosphorylated/dephosphorylated state of band 3. Show more

Keywords: Band 3, erythrocyte, phosphorylation, dephosphorylation, protein tyrosine kinase, protein tyrosine phosphatase

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 183-194, 2007

Authors: Eugster, M. | Häusler, K. | Reinhart, W.H.

Article Type: Research Article

Abstract: Viscosity measurements on very small capillary blood samples could be of considerable clinical interest. We have developed an oscillating viscometer for very small volumes, which consists of a glass capillary containing 7 μl of blood, which is part of an oscillating torsional resonator. The damping of the sinusoidal oscillations depends on the density and viscosity of the fluid, which allows blood viscosity measurements. The instrument was first evaluated in comparison with a standard blood viscometer (Contraves LS 30). Blood from healthy volunteers anticoagulated with EDTA was adjusted to hematocrit levels of 20, 30, 40, 50, and 60%, respectively. A strong …correlation was found between hematocrit and oscillating viscosity (y=0.17x−2.05, r=0.969, p<0.0001) and between oscillating and conventional high shear viscosity (y=1.11x−0.62, r=0.971, p<0.0001). Blood viscosity measured in venous or capillary blood of normal subjects was similar (p=0.63). Bedside viscosity measurements on capillary blood drawn from a finger prick during routine blood glucose measurements in patients with diabetes mellitus showed lower blood viscosity than controls (3.62±0.87 vs 4.79±0.59 mPa.s, p=0.0007), which is in contrast to earlier publications, and may be explained by the lower hematocrit in our diabetic patients (34.7±6.0% vs. 43.1±1.9%, p<0.0001). Blood viscosity was independent of the actual glucose level (range 3–17 mmol/l). Capillary blood anticoagulated with EDTA was drawn by heel prick from 23 newborns. Blood viscosity was higher (5.66 ±2.47 mPa.s) than in adult controls (see above), which could be explained by the dependence on the higher hematocrit (46.4 ±8.6%). We conclude that viscosity measurements can be made on very small samples such as capillary blood from diabetic patients or newborn babies with this new oscillating viscometer. It remains to be determined if such new informations have clinical implications. Show more

Keywords: Blood, diabetes mellitus, hematocrit, newborns, viscosity

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 195-202, 2007

Authors: Prantl, L. | Pfister, K. | Kubale, R. | Schmitt, St. | Stockhammer, V. | Jung, W. | Zorger, N. | Herold, T. | Nerlich, M. | Stehr, A. | Jung, E.M.

Article Type: Research Article

Abstract: Objective: The aim of this study was to evaluate the clinical value of color coded Doppler sonography (CCDS) and contrast-enhanced harmonic imaging (CHI) for ultrasound (US) monitoring the integrity of free-flap vascular grafts. Patency of microvascular anastomoses and perfusion as well as microcirculation of the transplanted tissue were analysed. Patients and methods: Fifteen free parascapular flap grafts performed over a period of three years by a single surgeon were examined with CCDS and CHI. The patients (12 male, 3 female) ranged in age from 16 to 60 years (average age 40±12). The follow-up period ranged from two weeks to 2.5 …years. CCDS were performed with a multifrequency linear transducer (5–10 MHz, Logiq 9, GE) with 3D flow detection. For detection and characterization, B scan of the flap tissue was compared to tissue harmonic imaging (THI) and Cross Beam with Speckle Reduction Imaging (SRI). US Pulse Inversion Harmonic Imaging (PIHI) after bolus injection of 2.5 ml Sonovue® was used for contrast enhancement. Results: Border and tissue structure of the flaps could be detected best in all 15/15 cases using Cross Beam Technology with SRI and THI. Correlations were found for flow parameters of the common femoral artery, popliteal artery and lower leg artery to the anastomotic vessels. 3D imaging with CCDS facilitated flow detection of elongated and small anastomotic vessels in 4/15 cases. Contrast-enhanced US with PIHI allowed dynamic flow detection of the microcirculation of the transplanted tissue over a depth of up to 3 cm with quantitative perfusion curves of the tissue microcirculation. Reduced US contrast enhancement with modified perfusion curves was seen in 2/15 cases with low anastomic flow in CCDS. Conclusion: Assessment of microvascular perfusion with contrast-enhanced ultrasound can provide valuable information on free flap viability. Contrast-enhanced US enables dynamic and quantitative flow detection of free flap tissue. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 203-216, 2007

Authors: Das, Bigyani | Bishop, Jeffrey J. | Kim, Sangho | Meiselman, Herbert J. | Johnson, Paul C. | Popel, Aleksander S.

Article Type: Research Article

Abstract: Knowledge of the effects of red blood cell aggregation on blood flow in small vessels is crucial to a better understanding of resistance changes in the venous microcirculation. Recent studies on rat spinotrapezius muscle indicate that enhanced red blood cell aggregation, induced by dextran 500, significantly affects velocity profiles at pseudoshear rates (the ratio of mean velocity to diameter) less than 40 s−1 . Since the use of a power-law model to describe these profiles does not provide a consistent rheological description, we have evaluated using the Casson model that has been widely used to characterize in vitro blood rheology. …In the present study, we report experimental values of rat blood viscosity in the presence of dextran 500 and combine these in vitro measurements with previously obtained in vivo venular velocity profiles to determine whether the Casson model can provide a valid description of in vivo velocity profiles. Our analysis shows that the two-phase Casson model with a peripheral plasma layer is in quantitative agreement with experimentally obtained velocity profiles obtained in venules of rat spinotrapezius muscle under low flow rate. These results have implications for pathological low-flow conditions, such as hemorrhage and sepsis, and they quantitatively describe blunted velocity profiles and elevated flow resistance in postcapillary venules. Show more

Keywords: Red blood cell aggregation, computational model, Casson model, two-phase flow, hemorheology, rat blood viscosity

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 217-233, 2007

Authors: Silva, A.S. | Saldanha, C. | Martins e Silva, J.

Article Type: Research Article

Abstract: The expression of acetylcholinesterase in proinflammatory cells has supported the hypothesis that this protein plays a role in intercellular adhesion. Previous results of our group show that velnacrine, an acetylcholinesterase inhibitor, increases the number of adherent leukocytes in post-capillary venules of Wistar rats' mesentery muscle. This works intends to evaluate the local application of velnacrine and acetylcholine in the inflammatory response at the microcirculatory network by studying the leukocytes/endothelium interactions in post-capillary venules of Wistar rats' cremaster muscle. The number and the speed of the rolling leukocytes, the number of adherent leukocytes and hemodynamic parameters were determined and also the …plasma levels of IL-1β. The results have shown that in the presence of velnacrine there is a significant increase of the rolling leukocytes (1.28±0.39 vs 1.93±0.20), as well as an increase of the adherent ones (0.86±0.72 vs 1.02±0.83). When acetylcholine is adding with velnacrine the number of rolling and adherent leukocytes decreases without changing the IL-1β plasma circulation induced by velnacrine. Our results suggest an anti-inflammatory role induced by ACh without full efficiency because the rolling leukocytes velocity was reduced without changes in the plasma level of IL-1β. Show more

Keywords: Inflammation, leukocytes, endothelium, velnacrine, acetylcholine

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 235-246, 2007

Authors: Tamer, Sule | Cefle, Kivanc | Gokkusu, Cahide | Ademoglu, Evin | Ozturk, Sukru | Vatansever, Sezai | Palanduz, Sukru | Guler, Kerim

Article Type: Research Article

Abstract: It is well known that various constituents of blood, especially lipids and proteins, and hematological parameters are altered in chronic liver diseases. These alterations have been shown to affect rheological parameters in various studies. However, it is not clear whether the etiology of chronic liver has any specific influence on flow dynamics of blood. In the present study, we analysed erythrocyte rigidity (ER), whole blood and plasma viscosity, and other factors related to blood rheology (including hematological parameters, plasma lipids and proteins) in healthy controls (n=20) and patients with post hepatitic and alcoholic cirrhosis (n=15 in each group). ER was …significantly higher (p<0.05) in both groups compared to controls. Although blood viscosity was found to be low in both groups, the difference reached statistical significance only in patients with alcoholic cirrhosis. On the other hand, when compared to controls, plasma viscosity was significantly lower in patients with alcoholic cirrhosis and significantly higher in patients with posthepatitic cirrhosis (p<0.05). When we compare post hepatic and alcoholic cirrhosis with each other, there was no significant difference in ER between the two groups. Show more

Keywords: erythrocyte rigidity, posthepatitic cirrhosis, alcoholic cirrhosis

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 247-252, 2007

Authors: Shin, Sehyun | Ku, Yun-Hee | Ho, Jian-Xun | Kim, Yu-Kyung | Suh, Jang-Soo | Singh, Megha

Article Type: Research Article

Abstract: The erythrocyte deformability of blood samples, of diabetes mellitus (DM) patients with and without microangiopathic complications such as nephropathy and retinopathy, is determined and is compared with that of healthy control. The erythrocyte deformability is measured in terms of elongation index (EI) with microfluidic ektacytometer, which is very sensitive to detect changes in EI of erythrocytes due to hyperglycemic process. Each measurement of diffraction pattern of erythrocyte suspension in a highly viscous polyvinyl pyrroridone (PVP) solution in a disposable microchannel is carried out. The results show that EI is well correlated with the levels of glycated hemoglobin and creatinine, as …determined from the blood samples of patients. A significant decrease in the EI in DM patients compared with that in normal control is observed. In patients with complications of chronic renal failure, end stage renal disease, retinopathy and with combination of retinopathy and nephropathy, the EI is significantly decreased in comparison with that of diabetes patients without these complications. Further reduction in EI is corresponded to the changes induced by the microangiopathy process despite the maintenance of blood glucose and glycated hemoglobin by drug therapy. Show more

Keywords: Erythrocyte deformability, nephropathy, retinopathy, creatinine, glycated hemoglobin

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 253-261, 2007

Authors: Hardeman, Max R.

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 263-263, 2007

Authors: Futrakul, Narisa | Sila-asna, Monnipha

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 36, no. 3, pp. 265-266, 2007