Clinical Hemorheology and Microcirculation - Volume 43, issue 4

Authors: Wang, Xifu | Wang, Xianwei | Wen, Tao | Guan, Li | Zhang, Yanlin | Zhu, Mingxia | Zhao, Jinyuan

Article Type: Research Article

Abstract: Carbon monoxide (CO) poisoning is a leading cause of poison-related morbidity and mortality. The severe complication of delayed neuropsychiatric sequelae seriously affects patient's living quality, but its mechanism remains controversial. In this study, we established an animal model by intraperitoneal injection of CO in rabbits at regular interval and kept the carboxyhemoglobin (HbCO) level in blood above 50% for at least 24 h. We investigated the dynamic changes in the hemorheological and coagulative properties of blood taken from venae jugularis interna before CO injection and at 30 min, 1–5 days after the last CO exposure. We found that RBC count, …hemoglobin (Hb) concentration, and hematocrit (Hct) increased on 1 day and remained high level till 5 day. Whole blood viscosities at different shear rates decreased significantly at 30 min and then increased 1 day later until day 4. RBC deformation index (DI) and aggregation index decreased at 30 min and recovered to normal on day 3. Plasma viscosity and fibrinogen augmented from 30 min until day 5. Prothrombin time (PT) and active partial thromboplastin time (APTT) prolonged remarkably at 30 min and went back to normal on 3 day, plasma [Ca2+ ] decreased at 30 min and approached to normal level on 3 day. The level of malondialdehyde (MDA) in RBCs at 30 min was significantly higher than that of control and recovered to normal on day 3. Our results suggest that the changes in hemorheology participate in the development of acute CO poisoning, which may play a role in delayed encephalopathy after acute CO poisoning. Show more

Keywords: Carbon monoxide poisoning, hemorheology, rabbit

DOI: 10.3233/CH-2009-1239

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 271-282, 2009

Authors: Baskurt, Oguz K. | Uyuklu, Mehmet | Ulker, Pinar | Cengiz, Melike | Nemeth, Norbert | Alexy, Tamas | Shin, Sehyun | Hardeman, Max R. | Meiselman, Herbert J.

Article Type: Research Article

Abstract: The International Society for Clinical Hemorheology organized a workshop to compare three instruments for measuring RBC aggregation: LORCA, Myrenne Aggregometer and RheoScan-A. The Myrenne Aggregometer provides indices at stasis (M) and at low shear (M1), with four indices obtained with the LORCA and RheoScan-A: amplitude (AMP), half-time (T1/2 ), surface area (SA) above (LORCA) or below (RheoScan-A) the syllectogram, and the ratio (AI) of the area above (LORCA) or below (RheoScan-A) the syllectogram to total area (AI). Intra-assay reproducibility and biological variability were determined; also studied were RBC in diluted plasma and in 1% 500 kDa dextran, and 0.003% glutaradehyde …(GA)-treated cells in plasma. All measurements were performed at 37°C. Standardized difference values were used as a measure of power to detect differences. Salient results were: (1) intra-assay variations below 5% except for RheoScan-A AMP and SA; (2) biological variability greatest for T1/2 with other indices similar for the three devices; (3) all instruments detected progressive changes with plasma dilution; (4) the Myrenne and LORCA, but not the RheoScan-A, detected differences for cells in dextran; (5) GA-treatment significantly affected the LORCA (AMP, T1/2 , SA, AI), the RheoScan-A (AMP, SA, AI) and the Myrenne M parameter. It is concluded that: (a) the LORCA, Myrenne and the RheoScan-A have acceptable precision and suitable power for detecting reduced aggregation due to plasma dilution; (b) greatly enhanced RBC aggregation may not be sensed by the RheoScan-A while the Myrenne M1 index may be insensitive to minor increases of cell rigidity; (c) future studies should define each instrument's useful range for detecting RBC aggregation. Show more

Keywords: Erythrocyte aggregation, light transmittance, light reflectance, intrumentation, standardized difference

DOI: 10.3233/CH-2009-1240

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 283-298, 2009

Authors: Lind, Lars | Andersson, Jessika | Larsson, Anders | Sandhagen, Bo

Article Type: Research Article

Abstract: It has previously been shown that the degree of shear stress (SS) in the carotid artery is related to both plaque occurrence and intima-media thickness (IMT). Since the echogenecity also is an important feature of plaques, we investigated if a reduced shear stress also is related to the echolucency of plaque and the intima-media complex. In the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study, a population-based study of 1016 subjects aged 70, left common carotid artery diameter, IMT, the grey scale median (GSM) of the intima-media complex (IM-GSM) and the blood flow velocity were measured by ultrasound. …Occurrence of plaque was noted, and the echogenecity of the plaques was visually estimated by the Gray–Weale classification. Shear stress was inversely related to both IMT and IM-GSM (p=0.0084 and p=0.003, respectively), independently of gender and coronary risk, estimated by the Framingham risk score. Shear stress was lower in subjects with carotid plaque (44% of the sample) than in those without (p=0.0013), and was inversely related to the echogenecity in the subjects with plaque (p=0.0092), independently of gender and coronary risk. A low shear stress in the common carotid artery was associated with both a thick IMT and an echolucent intima-media complex. A similar picture was seen when overt plaques were evaluated, suggesting that shear stress is of importance for both the extent and composition of atherosclerosis. Show more

Keywords: Blood viscosity, intima-media thickness, plaques, shear stress

DOI: 10.3233/CH-2009-1241

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 299-308, 2009

Authors: Ginsbourg, Shay | Levin, Shlomo | Einav, Shmuel | Korenstein, Rafi

Article Type: Research Article

Abstract: In this study, the human RBC capillary flow has been modeled by passing 11 μl of RBC suspension (Hematocrit = 6%) in phosphate buffer solution (PBS) of a viscosity of 1 and 2.6 cP (in the presence of 2% Dextran) through 5 μm pore diameter polycarbonate Nuclepore filters. We have developed a digitally controlled experimental system for measuring the RBC filterability at a constant driving pressure, in the range of 10–400 Pa, producing a wall shear stress range of 1–50 Pa. The RBC filterability was evaluated by measuring the cell suspension flow rate normalized by the PBS flow rate. The …RBC filterability has been found to be a nonlinear function of the driving pressure, having a single minimum locus at 25 Pa. Lowering the driving pressure below 25 Pa revealed an unexpected increase of the RBC filterability. The maximal RBC filterability (near unity) was detected at the lowest driving pressure (10 Pa) and the corresponding estimated RBC linear velocity while traveling through the capillary pore was as high as 800 μm/s. Increasing the driving pressure above 25 Pa confirmed previous results, where RBC filterability is monotonically and asymptotically increasing. Increasing the PBS medium viscosity from 1 to 2.26 cP significantly attenuated the RBC filterability and led to the anomalous increase of RBC deformability at the 10 Pa pressure range. We propose that the anomalous increase in RBC deformability was caused by RBCs undergoing spontaneous mechanical fluctuations. Show more

Keywords: RBC deformability, low Reynolds number, spontaneous mechanical fluctuations, Dextran solution viscosity, polycarbonate Nuclepore filters, wall shear stress

DOI: 10.3233/CH-2009-1242

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 309-319, 2009

Authors: Koutsiaris, Aristotle G.

Article Type: Research Article

Abstract: An empirical parametric equation with 2 bluntness parameters was introduced for describing the velocity profile of blood in the small arterioles and venules of small mammals, in vivo, with the basic approximations of the axisymmetric flow in cylindrical geometry, zero velocity at the wall and a blunter than parabolic flow profile. The purpose was to evaluate the usefulness of this equation in describing the velocity profile and in estimating the volume flow when only one velocity measurement is available near the vessel axis. The equation was tested on 17 velocity profiles (9 arteriolar and 8 venular) previously measured by particle …image velocimetry (PIV) techniques, at diameters ranging from 17 to 38.6 μm. The correlation coefficients of each experimental profile were higher than 0.96. The average relative error-bias measured at 10 radial segments ranged between −5% to 1%, leading to an average relative volume flow estimation error for all the 17 velocity profiles of −1.8% with a standard deviation of 4.3%. Show more

Keywords: Velocity profile, in vivo, microvascular hemodynamics

DOI: 10.3233/CH-2009-1243

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 321-334, 2009

Authors: Famodu, A.A. | Awodu, O.A.

Article Type: Research Article

Abstract: Background: Some epidemiological studies have found anthropometric indices to be related to cardiovascular disease risk factors. Fibrinogen – an acute phase reactant protein – is central in the haemostatic system. Its associations with cardiovascular diseases have been well documented. A possible association between measures of body fat and fibrinogen has been reported. Aims: To study the relationship of fibrinogen (PFC), plasma viscosity (PV) and haematocrit (HCT) with measures of obesity (body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR)) in apparently healthy Nigerians living in Ilisan-Remo, a semi-urban community. Subjects and methods: The study population comprised …of apparently healthy mono-ethnic Nigerians living in Ilisan-Remo town. Obesity was measured using the body mass index, waist circumference, waist-to-hip ratio and waist-to-height ratio. Blood samples were analyzed for rheological parameters (plasma fibrinogen, plasma viscosity, haematocrit and the erythrocyte sedimentation rate (ESR) using standard methods. Results: A total of 122 subjects were studied, 46 males (mean age 57±15.7 years) and 76 females (mean age 58.92±17.99 years). The mean systolic blood pressure was 138.5 mmHg for males and 135.2 mmHg for females respectively. The independent variables (BMI, waist-to-hip ratio) were divided into 2 groups using the 75th percentile cut off. In the BMI group, the diastolic blood pressure, haematocrit and plasma viscosity were significantly higher in males (p<0.0001) in the >75th percentile group but not in females. Using the waist circumference; plasma viscosity and diastolic blood pressure were higher in males (p<0.0001) in the >75th percentile group. In females the haematocrit and blood viscosity were significantly higher (p=0.0074, p=0.0434) respectively in the >75th percentile group. Using stepwise multiple regression analysis, the waist circumference and BMI were found to be significant determinant for systolic and diastolic blood pressure. The BMI was significant determinant for the haemorheological cardiovascular disease (HCVD) risk factors except fibrinogen. While the waist circumference was a significant predictor of all the haemorheological cardiovascular disease risk factors (p<0.0001). Conclusion: While the BMI and the WHR may be good predictors of CVD (cardiovascular disease) risk factors, we have shown that the waist circumference may be a better predictor of haemorheological cardiovascular disease risk factors than the BMI in Nigerians. Show more

Keywords: Anthropometric indices, haemorheological cardiovascular disease risk factors, Nigerians

DOI: 10.3233/CH-2009-1244

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 335-344, 2009

Authors: Kung, Chien-Min | Tseng, Zu-Lin | Wang, Hai-Lung

Article Type: Research Article

Abstract: Background: This study examines that erythrocyte was fragility-susceptible in diabetes. Methods: Forty-five outpatients with type 2 diabetes mellitus (aged 46 ± 13 years) and 20 healthy individuals with no history of diabetes disorders (aged 43 ± 7 years) were randomly selected in this study. All subjects were analysis for blood glucose, glycosylated hemoglobin and erythrocyte osmotic fragility tests. Results: The data for blood glucose (p<0.001), glycosylated hemoglobin (p<0.001), start hemolysis of erythrocyte (p<0.001), medium corpuscle hemolysis (p<0.001) and complete hemolysis (p=0.001) were significantly higher for diabetes than that of non-diabetes. The erythrocyte osmotic fragility in start hemolysis (r=0.479, …p<0.001), medium corpuscle hemolysis (r=0.454, p<0.001) and complete hemolysis (r=0.277, p=0.025) were closely correlated with red blood cell glycosylated hemoglobin. Investigation of associations with red cell fragility-susceptible, diabetic patients had significantly increased risks of cell hemolysis on start hemolysis (ORs, 32.67; 95% CIs, 7.201–148.19), medium corpuscle hemolysis (ORs, 2.53; 95% CIs, 0.831–7.695) and complete hemolysis (ORs, 4.28; 95% CIs, 1.386–13.202) (all p<0.05 for linear trends) of erythrocyte to non-diabetes controls. Conclusions: This study demonstrated that osmotic fragility of erythrocyte was greater in type 2 diabetic subjects compared to non-diabetic controls and red blood cell fragility was positively correlated with glycosylated hemoglobin. Hence, it is necessary to emphasize increasing investigations of pathogenic mechanisms exacerbated by red cell fragility to prevent complications of diabetes mellitus. Show more

Keywords: Diabetes, glycosylated hemoglobin, HbA1c, hyperglycemia

DOI: 10.3233/CH-2009-1245

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 345-351, 2009

Authors: Baskurt, Oguz K. | Meiselman, Herbert J.

Article Type: Other

DOI: 10.3233/CH-2009-1255

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 353-354, 2009

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 43, no. 4, pp. 355-360, 2009