Clinical Hemorheology and Microcirculation - Volume 34, issue 1-2

Authors: Chanawirat, Atchareeya | Khemapech, Sirima | Patumraj, Suthiluk | Siriviriyakul, Prasong

Article Type: Research Article

Abstract: The objective of this study is to examine roles of genistein in postmenopausal induced-endothelial dysfunction and bone loss, the ovariectomized (OVX) rat model was used. The animals were divided into three groups of sham treated with vehicle (DMSO 100 μl/day; Shamveh ), OVX treated with vehicle (OVXveh ) and OVX treated with genistein (0.25 mg/kg/day; OVXgen ). At 3 and 7 weeks after the surgery, endothelial dysfunction in mesenteric microcirculation of each group was determined by using intravital fluorescence microscopy and analyzed with digital image software. The parameters of bone mass density (BMD) and bone formation marker were represented by …percentage of ash/dry matter and osteocalcin activity (using radioimmunoassay (RIA)), respectively. Mean arterial pressures (MAP) in OVXveh groups were significantly increased compared to their aged-matched sham groups (p<0.05). Interestingly, the treatment of genistein could significantly attenuate this abnormality (p<0.001). Besides, it could increase the vascular response to acetylcholine (Ach; 10−6 M) significantly compared to OVX-rats (p<0.05). Moreover, BMD and osteocalcin activity were significantly increased in Ovxgen as well. Therefore, our findings suggested that genistein supplementation could effectively prevent endothelial dysfunction and bone loss in OVX-rat model. Show more

Keywords: Genistein, endothelial dysfunction, bone, ovariectomized rat

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 309-314, 2006

Authors: Sridulyakul, Pattrin | Chakraphan, Daroonwan | Patumraj, Suthiluk

Article Type: Research Article

Abstract: This paper was aimed to study whether vitamin C supplementation reverses the diabetes-induced endothelial cell dysfunction occurred in streptozotocin (STZ)-rats or not. The animals were divided into four groups: control and diabetes rats (DM, using iv. injection of 50 mg/kg.bw STZ), and two DM rats treated with vitamin C (1 g/l) starting on day 2 (DM + VitCday2 ) and week 6th after STZ-injection (DM + VitC6wks ). The mesenteric microcirculation was observed using fluorescence videomicroscopy. Based on the recorded videoimages, microvascular responses to acetylcholine (Ach; 10–5 M) and number densities of leukocyte adhesion in venules were evaluated using the …Global Lab II image software. In DM group, blood glucose and glycosylated hemoglobin were significantly increased, while the body weight and plasma vitamin C levels were decreased significantly compared to their controls. Ach-induced vasodilation was decreased, while the number of leukocyte adhesion was increased significantly compared to their controls (p<0.01). These abnormalities induced by DM were prevented by supplementation of vitamin C in DM + VitCday2 group. Six-weeks delayed treatment of vitamin C (DM + VitC6wks ) demonstrated increase in the Ach-induced vasodilation with significant decrease in the leukocyte adhesion. It was indicated that vitamin C supplementation could reverse diabetes-induced endothelial cell dysfunction in mesenteric microcirculation. Show more

Keywords: Diabetes, endothelial dysfunction, leukocyte adhesion, vitamin C, vasodilation

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 315-321, 2006

Authors: Cheung, Anthony T. | Duong, Patricia L. | Driessen, Bernd | Chen, Peter C. | Jahr, Jonathan S. | Gunther, Robert A.

Article Type: Research Article

Abstract: Systemic function and oxygenation changes during hemorrhagic shock treatment were continuously monitored and correlated with real-time microvascular changes. After splenectomy, each dog (n=12) was hemorrhaged (MAP=∼50 mmHg; ∼40% blood loss=32–36 ml/kg) and randomly assigned to 4 resuscitation groups: autologous/shed blood, hemoglobin-based oxygen-carrier/Oxyglobin® , crystalloid/saline, and colloid/Hespan® . Systemic function and oxygenation changes were continuously monitored and measured using standard operating room protocols. Computer-assisted intravital microscopy was used to non-invasively videotape and objectively analyze and quantify real-time microvascular changes in the conjunctival microcirculation. All measurements were made during pre-hemorrhagic (baseline), post-hemorrhagic and post-resuscitation phases of the study. Pre-hemorrhagic microvascular changes were …similar in all 12 dogs (venular diameter=43±12 μm; red-cell velocity=0.6±0.2 mm/s). All dogs showed similar significant (P<0.01) post-hemorrhagic microvascular changes: ∼20% decrease in venular diameter; ∼80% increase in red-cell velocity. These microvascular changes correlated with post-hemorrhagic systemic function and oxygenation changes. The resuscitations restored microvascular changes to pre-hemorrhagic values; the microvascular reversals also correlated with post-resuscitation systemic function changes in all groups. However, only shed blood resuscitation restored oxygenation level close to pre-hemorrhagic values. All 12 dogs survived resuscitation treatments despite differences in oxygen-carrying capability between groups. Show more

Keywords: Systemic function, oxygenation, hemorrhagic shock, blood substitutes

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 325-334, 2006

Authors: Sakai, Hiromi | Tsuchida, Eishun

Article Type: Research Article

Abstract: Hemoglobin-Vesicles (HbV; diameter, 250 nm) are artificial O2 carriers encapsulating purified and concentrated human Hb solution in phospholipid vesicles (liposomes), and their safety and efficacy, as a transfusion alternative, have been studied. In this paper, we summarized the characteristics of HbV that have been clarified by the microcirculatory observations.

Keywords: Blood substitutes, liposome, microcirculation, EDRF, oxygenation

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 335-340, 2006

Authors: Maeda, Nobuji | Cicha, Iwona | Tateishi, Norihiko | Suzuki, Yoji

Article Type: Research Article

Abstract: The effect of triglyceride in plasma on RBC aggregation was examined, and the prospective influence on the flow of RBCs in microcirculation and the O2 release was discussed. To minimize the individual differences, blood samples were collected from one subject 2 hrs after high-fat and low fat meals. Triglyceride content in plasma was measured by an enzymatic method, and the rate of rouleaux formation was measured with a low shear rheoscope. The rate of rouleaux formation was increased with the increase of triglyceride concentration. Our previous findings suggested some functional impairment in microcirculation. (1) The enhanced RBC aggregation tends …to reduce flow resistance in arterioles, but results in inhomogeneous flow of RBCs in capillaries. (2) The sclerotic change of microvessels alters flow behavior of RBCs, and thereby flow resistance is increased. (3) The enhanced RBC aggregation reduces O2 release from RBCs flowing in microvessels. In conclusion, high triglyceride level in plasma not only changes flow behavior of RBCs in microcirculation and thus increases flow resistance, but also prevents homogeneous tissue oxygenation. Show more

Keywords: Red blood cell aggregation, plasma triglycerides, cell-free layer, flow resistance, O$_{2}$ release

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 341-346, 2006

Authors: Zheng, Xiaoxiang | Ning, Gangmin | Yang, Yong

Article Type: Research Article

Abstract: To reveal the intracellular distribution of nitric oxide (NO) in single cell and to detect NO quantitatively in animal models, various methods are developed. A confocal microscope and 3D visualization technique were applied to visualize NO concentration in arbitrary directions and in different sections of cells. It was shown that NO distributions in cultured neurons of rat hipopocampus were not homogeneous. A kind of highly sensitive and selective NO electrode was utilized to measure the NO concentration in SD rat hippocampus, simultaneously with blood pressure and ECG recording. By the administration of NG -nitro-L-arginine methylester (L-NAME), the changes of NO …level in the hippocampus in vivo were detected. It was shown that the NO level decreased greatly when NOS was inhibited by L-NAME with significant increase in blood pressure. The developed methods may be helpful to investigate the physiological mechanism of NO and its role in pathology. Show more

Keywords: NO detection, confocal microscope, NO electrode

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 347-352, 2006

Authors: Shin, S. | Park, M.S. | Ku, Y.H. | Suh, J.S.

Article Type: Research Article

Abstract: Though the aggregation of red blood cells (RBCs) is a major determinant of blood viscosity, there have not been any available techniques to measure the effect of RBC aggregation on blood viscosity over a range of shear rates. The microfluidic shearing technique with vibration has been applied to an aggregometer for measuring the dynamic aggregation characteristic of RBCs. In measuring backscattered light intensity I(t) and pressure p(t) over time, both aggregation and the stress–shear rate information can be determined simultaneously. The feasibility and accuracy of the new aggregation measurement technique has been demonstrated to correlate with blood viscosity for normal …and heated blood. We found that RBC aggregability showed shear-dependent behavior, which can be correlated directly with shear-thinning blood viscosity. The present measurements of the dynamic aggregation characteristic over shear rate enable the interpretation of the shear-rate dependent blood viscosity, which is greatly affected by RBC aggregation. Show more

Keywords: Microfluidics, shear, aggregation, red blood cell, vibration

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 353-361, 2006

Authors: Ning, Gangmin | Bai, Yan | Yan, Weimin | Zheng, Xiaoxiang

Article Type: Research Article

Abstract: This paper was aimed to apply telemetry technology to investigate the cardiovascular activity of rats. A subminiature radio transducer was implanted in the body of rat to measure beat to beat blood pressure, ECG, body temperature, as well as the activity of rat continuously. Mathematic tools were developed to extract beat to beat cardiovascular parameters. Accordingly, spectral analysis of blood pressure variability and heart rate variability was performed to analyze cardiovascular activity in both normotensive and hypertensive rats. New indices were also established to assess the fluctuation of blood pressure of hypertensive rats and thus the effect of anti-hypertensive medication. …The ratio of low frequency power to high frequency power in heart rate variability of normotensive rats was much lower than that of hypertensive rats. In hypertensive rats, the blood pressure variability demonstrated significant increase. Furthermore, the circadian rhythm of blood pressure and heart rate variability also altered in hypertensive rats. After the treatment, the blood pressure of hypertensive rats dropped significantly. Meanwhile, the developed indices, such as 24h smoothness index were consistent with the behavior of blood pressure satisfactorily. The results suggest that the developed methods are powerful in studying cardiovascular system as well as evaluating the effects of antihypertensive medication objectively. Show more

Keywords: Telemetry, cardiovascular activity, blood pressure variability, heart rate variability, smoothness index

Citation: Clinical Hemorheology and Microcirculation, vol. 34, no. 1-2, pp. 363-371, 2006