Clinical Hemorheology and Microcirculation - Volume 28, issue 4

Authors: Jung, F. | Mrowietz, C. | Seyfert, U.T. | Grewe, R. | Franke, R.P.

Article Type: Research Article

Abstract: It was investigated whether the NO‐donor SIN‐1, the active metabolite of molsidomine, influenced the activation of platelets, the formation of circulating platelet aggregates, the spontaneous aggregation of platelets and the activation of the clotting system triggered by a body foreign surface in an in vitro closed‐loop perfusion model. With human platelet‐rich plasma at micromolar concentrations SIN‐1 exerted pronounced effects on the interaction between platelets and an exogenous surface. In the absence of SIN‐1, the number of circulating single platelets decreased significantly, which could be due either to the formation of circulating platelet aggregates or to the adhesion of platelets to …the stent. Both these processes were blocked by the addition of SIN‐1. Moreover, the platelets exhibited hyperaggregability in the absence of SIN‐1 whereas the NO‐donor was able to completely inhibit spontaneous platelet aggregation. Similar results were obtained in flow cytometry experiments. Without SIN‐1, high platelet surface densities of both the GPIb/IX and GPIIb/IIIa receptors were observed. In addition, the density of the fibrinogen receptor increased significantly with the number of perfusion cycles. SIN‐1 was able to suppress the augmented GPIIb/IIIa receptor expression significantly. Molsidomine seemed to have the potential to reduce the incidence of thrombotic processes triggered by the exogenous surface of the stent. Show more

Keywords: Haemocompatibility, coronary stents, in vitro, platelet aggregation, platelet activation

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 189-199, 2003

Authors: Szikszai, Zita | Ujhelyi, László | Imre, Sándor G.

Article Type: Research Article

Abstract: Deformability and lipid peroxidation (LP) have been compared in erythrocytes of 45 chronic hemodialysis patients and 30 healthy subjects. The relative cell transit time (RCTT), correlating negatively to deformability, was measured using a St. George filtrometer. Thiobarbituric acid reactive material was measured and expressed as nanomoles of malondialdehyde (MDA) per gram of hemoglobin as a marker of LP. RCTT and MDA were found to be significantly higher not only before but also after HD compared with controls. Weak negative correlations were found between RCTT and the dosage of EPO as well as between RCTT and the daily amount of …urine. These observations indicate the importance of residual renal function and the beneficial effect of EPO on erythrocyte deformability. The mean values of results suggest that HD does not affect the erythrocyte injury. The individual modifications of RCTT and MDA are also discussed. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 201-207, 2003

Authors: Birnbaum, Jürgen | Lehmann, Christian | Stauss, Harald M. | Weber, Mathias | Georgiew, Alexander | Lorenz, Björn | Pulletz, Sven | Gründling, Matthias | Pavlovic, Dragan | Wendt, Michael | Kox, Wolfgang J.

Article Type: Research Article

Abstract: Impairment of the intestinal microcirculation has been recognized as an important factor in the pathogenesis of endotoxin related sepsis syndrome. We investigated the effects of endotoxemia on the variability of intestinal microvascular blood flow (IMBF) and arterial blood pressure (BP) in a prospective, randomized, controlled animal study. Recordings of IMBF (laser Doppler fluxmetry) and BP were performed before, two and four hours after i.v. injection of either placebo or endotoxin (5 mg/kg b.w. lipopolysaccharide from E. coli, serotype O55:B5). Control experiments were performed with systemic (clonidine) and local intestinal (surgery) sympathectomy. Spectral analysis was performed using the autoregressive approach. Spectral …power was determined in two frequency bands (low frequency (LF): 0.27–0.74 Hz; high frequency (HF): 0.76–3.00 Hz). Two hours after endotoxin challenge a significant decrease in IMBF was observed. LF spectral power of IMBF and BP increased significantly in the endotoxin challenged group, while no effects were observed in the placebo group. Four hours after endotoxin administration IMBF decreased further and LF spectral power of IMBF and BP remained elevated. Denervation prevented the decrease in IMBF but did not abolish the LF power increase. Clonidine administration attenuated the IMBF decrease and significantly diminished the increase in LF spectral power of IMBF and BP. We conclude that endotoxemia is associated with increased sympathetic outflow to the systemic vasculature, as indicated by the increase in LF spectral power of arterial blood pressure. The increase in LF variability of IMBF is secondary to the increase in LF spectral power of BP, since it could be attenuated by systemic and not by local intestinal sympathectomy. Show more

Keywords: Laser Doppler fluxmetry, power spectral analysis, sepsis, clonidine, sympathectomy

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 209-220, 2003

Authors: Nagel, Edgar | Vilser, Walthard | Lanzl, Ines

Article Type: Research Article

Abstract: Background: The present study investigates the possible application of a commercially available on‐line measuring device of retinal vessels for conjunctival vessel assessment. Methods: Repeated measurements in one randomly chosen eye were performed in 11 healthy volunteers (mean age 42.9±10 years). Measurements of one conjunctival vessel were obtained first without a stimulus followed by measurements after the application of one drop of a topical vasoconstrictor. The examinations were performed by Retinal Vessel Analyzer (RVA® , IMEDOS/Germany). This system determines automatically on‐line the vessel diameter along a chosen vessel segment. Results: Measurements in the native state without eye drop application showed …an intraclass correlation coefficient of 0.97 and a mean variation coefficient of 1.8%. After application of the topical vasoconstrictor a short acting vasodilatation was observed with a magnitude of +10.9%±14.9 (p<0.001), followed by an increasing vasoconstriction (after 4 min −12.0%±7.6; p=0.004). One volunteer had no measurable conjunctival vessels in the baseline measurements and was therefore excluded from the study. Discussion: The suggested technique allows the measurement of changes in conjunctival vessel diameter with high precision. The method represents a non invasive technique for the assessment of effects on conjunctival vessels caused by topical or systemic drugs. Show more

Keywords: Conjunctival microcirculation, vessel diameter, retinal vessel analyzer

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 221-227, 2003

Authors: Franke, R.P.

Article Type: Abstract

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 229-243, 2003

Authors: Falcó, C. | Vayá, A. | Iborra, J. | Moreno, I. | Palanca, S. | Aznar, J.

Article Type: Research Article

Abstract: Erythrocyte aggregability was determined by a laser backscattering light technique in 23 β minor thalassemia carriers and in 36 age and sex matched controls. The aggregation time (Ta) was statistically higher in cases than in controls (2.8±1.0 vs 2.3±0.4, p<0.05) and the aggregation index at 10 sec (AI10 ) was statistically lower (25.1±5.7 vs 28.2±3.8, p<0.05), suggesting both parameters a statistically lower erythrocyte aggregability tendency. However, the total disaggregation threshold (γD) was statistically higher in cases than in controls (134.4±34.1 vs 105.1±33.1, p<0.05), indicating that once aggregates are formed a higher shear rate is needed to break them up. No …differences were observed in plasmatic factors, i.e., fibrinogen, total cholesterol and triglycerides, that could have influenced erythrocyte aggregation. A negative statistically significant correlation was found between erythrocyte indexes and the total disaggregation threshold. The lower erythrocyte aggregation found in minor thalassemia carriers could be attributed in part to the morphological alterations, although others mechanisms such as modifications in the membrane structure of the RBC can not be ruled out. Show more

Keywords: Thalassemia, erythrocyte aggregability, erythrocyte disaggregability, laser backscattering aggregometer

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 245-249, 2003

Authors: Nowak‐Piszczek, Ewa | Wyrwicz, Grażyna | Dąbrowski, Zbigniew | Smoleński, Olgierd | Spodaryk, Krzysztof

Article Type: Research Article

Abstract: These studies were focused on the influence of two treatment methods of patients with chronic renal disease on RBC deformability. In peritoneal dialysed‐patients (PD) erythrocytes exhibited a decrease in their deformability as compared to control subjects whereas this parameter in RBC deriving from hemodialysed patients (HD) was not altered. The alleviating effect of plasma components on deformability of erythrocytes was confirmed after the isolation of a pure faction of these cells as the parameter became worse. The activity of studied enzymes: acetylcholinesterase (Ache), dehydrogenase glucose‐6‐phosphate (G‐6‐PD) and glutathione reductase (GR) maintained their physiological values in both dialysis groups.

Keywords: Hemodialysis, peritoneal dialysis, erythrocyte deformability, acetylcholinesterase, dehydrogenase glucose‐6‐phosphate, glutathione reductase

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 251-257, 2003

Authors: Li, Min | Liu, Liang | Zhang, Xiaohui | Yeh, Mei‐Ling | Liao, Fulong

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 259-261, 2003

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 263-263, 2003

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 28, no. 4, pp. 265-269, 2003