Clinical Hemorheology and Microcirculation - Volume 21, issue 1

Authors: Martínez, M. | Vayá, A. | Alvariño, J. | Barberá, J.L. | Ramos, D. | López, A. | Aznar, J.

Article Type: Research Article

Abstract: The rheological profile of 45 patients who had kidney failure and were undergoing periodical hemodialysis was studied to ascertain whether they showed rheological alterations and if these alterations improved after hemodialysis. Our results indicate that the patients studied suffer rheological alterations with respect to the control group, specifically increased plasma fibrinogen (436 \pm 119 vs 271 \pm 43 mg/dl, p<{} 0.001), increased plasma viscosity (1.30 \pm 0.10 vs 1.22 \pm 0.05 mPa.s, p<{} 0.001), higher erythrocyte aggregability (8.3 \pm 1.2 vs 7.4 \pm 1.4, p<{} …0.01) and a lower hematocrit (31.2 \pm 5.9 vs 43.4 \pm 3.7, p<{} 0.001). In contrast, erythrocyte deformability did not seem to be altered with respect to the control group. The analyses carried out immediately after hemodialysis showed that in general the rheological profile worsened during this treatment; there was a significant increase in fibrinogen and in plasma viscosity. The rheological alterations detected may play a role in the development of the atherosclerosis processes often experienced by these patients. Show more

Keywords: Hemorheology, renal failure, hemodialysis

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 1, pp. 1-6, 1999

Authors: Wautier, Jean‐Luc | Schmid‐Schönbein, Geert W. | Nash, Gerard B.

Article Type: Research Article

Abstract: The measurement of leukocyte rheology in vascular disease is a recent development with a wide range of new opportunities. The International Society of Clinical Hemorheology has asked an expert panel to propose guidelines for the investigation of leukocyte rheology in clinical situations. This article first discusses the mechanical, adhesive and related functional properties of leukocytes (especially neutrophils) which influence their circulation, and establishes the rationale for clinically‐related measurements of parameters which describe them. It is concluded that quantitation of leukocyte adhesion molecules, and of their endothelial receptors may assist understanding of leukocyte behaviour in vascular disease, along with measurements of …flow resistance of leukocytes, free radical production, degranulation and gene expression. For instance, vascular cell adhesion molecule (VCAM‐1) is abnormally present on endothelial cells in atherosclerosis, diabetes mellitus and inflammatory conditions. Soluble forms of intercellular adhesion molecule (ICAM‐1) or VCAM can be found elevated in the blood of patients with rheumatoid arthritis or infections disease. In the second part of the article, possible technical approaches are presented and possible avenues for leukocyte rheological investigations are discussed. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 1, pp. 7-24, 1999

Authors: Jung, F. | Keßler, H. | Pindur, G. | Sternitzky, R. | Franke, R.P.

Article Type: Research Article

Abstract: The oxygen partial pressure (pO_2 ) in the anterior tibial muscle was measured in n={} 12 (6 physically active and 6 sedentary) apparently healthy subjects. This was the first time a flexible micro catheter with an outer diameter of 0.45 mm was used during skeletal muscular activity in men. A two level tread mill test which is used in the diagnosis of peripheral arterial occlusive disease was chosen to induce physical stress. In the healthy volunteers a pO_2 increase was noted at the beginning of exercise. This was followed by a pO_2 decrease …because of an increased O_2 demand in the working muscle. The initial pO_2 increase was thought to be due to the recruitment of capillaries and not the subsequently increased heart rate. At rest and during activity pO_2 values were higher in physically active subjects than in the sedentary and the exercise induced decrease of pO_2 values was slower and in addition to this the compensation to baseline values quicker. Show more

Keywords: Oxygen partial pressure, skeletal muscle, exercise

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 1, pp. 25-33, 1999

Authors: Pfafferott, Conrad | Moessmer, Georg | Ehrly, Albrecht M. | Bauersachs, Rupert M.

Article Type: Research Article

Abstract: The objective of the study was to identify the relative importance of erythrocyte flow resistance and aggregation in acute and chronic coronary syndromes. 117 subjects in five groups were studied: (1) 34 patients shortly after acute myocardial infarction (AMI) before reperfusion therapy; (2) 27 patients with unstable and (3) 21 with stable angina pectoris (AP); (4) 14 age‐matched control patients and (5) 21 healthy volunteers. Single erythrocyte transit times were measured using the Cell Transit Analyser. Shear dependent elongation and aggregation was measured by a modified computerized Myrenne aggregometer. Leukocyte count was increased in coronary artery disease (CAD), especially in …acute syndromes (mean \pm SD for groups 1–5): 12.2 \pm 4.5; 10.0 \pm 5.4; 8.0 \pm 2.0; 8.0 \pm 3.7; 7.0 \pm 2.0 (pl^{-1} )). Platelets, hematocrit, fibrinogen, \alpha_{2} ‐macroglobulin did not differ between the groups. Plasma viscosity (mPa s) was elevated in AMI and stable AP: 1.34 \pm 0.10; 1.30 \pm 0.09; 1.32 \pm 0.08; 1.27 \pm 0.07; 1.27 \pm 0.05. Erythrocyte filtrability was not different as was the shear dependent deformation. Aggregation parameters such as \gamma T_{\min} were elevated in CAD: 180 \pm 70; 159 \pm 60; 166 \pm 59; 115 \pm 43; 113 \pm 51 (s^{-1} ). Erythrocyte deformability, measured with two independent methods, does not appear to contribute to the pathophysiology of acute coronary syndromes. Erythrocyte aggregation and plasma viscosity were again found increased both in unstable and stable coronary disease. It is unlikely that increased red cell aggregation contributes to emergence of AMI. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 1, pp. 35-43, 1999

Authors: Riha, P. | Wang, X. | Liao, R. | Stoltz, J.F.

Article Type: Research Article

Abstract: The measurement of clot elasticity and fracture strain is carried out using a rotational rheometer with a controlled stress system. The elasticity is quantified by a shear elastic modulus and fracture strain by a critical strain (deformation) when the clot begins to break up. The results indicate a decrease of elasticity and increase of fracture strain of the clot with increasing hematocrit. Moreover, the elastic modulus of the clot is not constant but increasing with deformation.

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 1, pp. 45-49, 1999

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 21, no. 1, pp. 51-77, 1999