Clinical Hemorheology and Microcirculation - Volume 39, issue 1-4

Authors: Antonova, Nadia | Riha, Pavel | Ivanov, Ivan

Article Type: Research Article

Abstract: Time variation of whole human blood conductivity and shear stresses were investigated at rectangular and trapezium-shaped Couette viscometric flow under electric field of 2 kHz. The kinetics of conductivity signals were recorded both under transient flow and after the complete stoppage of shearing at shear rates from 0.94 to 94.5 s−1 and temperatures T=25°C and 37°C. Contraves Low Shear 30 rotational viscometer as a base unit and a concurrent measuring system, including a device, developed by the conductometric method with a software for measurement of conductivity of biological fluids (data acquisition system), previously described (IFMBE Proceedings Series, Vol. 11, …2005, pp. 4247–4252; Clin. Hemorheol. Microcirc. 35(1/2) (2006), 19–29), were used for the experiments. The obtained experimental relationships show that the human blood conductivity is time, shear rate, hematocrit and temperature dependent under transient flow. It is also dependent on the regime of the applied shear rates. Non-linear curve approximation of the growth and relaxation curves is done. The results show that valuable information could be received about the kinetics of “rouleaux formation” and the time dependences of the blood conductivity follow the structural transformations of RBC aggregates during the aggregation–disaggregation processes. The results suggest that this technique may be used to clarify the mechanism of dynamics of RBC aggregates. Show more

Keywords: RBC aggregation, blood conductivity, low shear rate viscometry

DOI: 10.3233/CH-2008-1114

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 69-78, 2008

Authors: Arató, E. | Jancsó, G. | Sínay, L. | Kürthy, M. | Lantos, J. | Ferencz, S. | Horváth, S. | Shafiei, M. | Kasza, G. | Verzár, Z. | Kollár, L. | Rőth, E. | Wéber, G. | Menyhei, G.

Article Type: Research Article

Abstract: After revascularization of an acute arterial occlusion the development of a serious ischaemic-reperfusion injury is a menacing challenge and a hard task in peripheral vascular surgery. A whale of evidences point to oxidative stress, as an important trigger, in the complex chain of events leading to reperfusion injury. In the present study authors aimed to examine oxidative stress parameters, antioxidant–prooxidant state and leukocyte adhesion molecules (CD11a and CD18) expression following acute revascularization surgery of lower limb. 10 patients were examined in the prospective randomized study. Peripheral blood sample was collected in ischaemic period, and after reperfusion in the 2nd …and 24th hours, and on 7th day. Superoxide-dismutase activity, reduced glutathion concentration and leukocytes free radical production were measured. The degree of lipidperoxidation was marked with the quantity of malondialdehyde. The expressions of adhesion molecules were measured with flowcytometry. The speed and rate of free radical production significantly increased in the early reperfusion (p<0.05). The level of antioxidant enzymes decreased after revascularization. The CD11a and CD18 expression of the granulocytes significantly (p<0.05) decreased right after the revascularization, but with a gradual elevation until the 7th day they exceed the ischaemic value. Our results showed a time specific turnover of the sensitive antioxidant–prooxidant balance after revascularization operation. Show more

Keywords: Ischaemia–reperfusion, vascular surgery, oxidative stress, reperfusion injury

DOI: 10.3233/CH-2008-1070

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 79-85, 2008

Authors: Katsanos, K. | Moutzouri, A. | Karnabatidis, D. | Siablis, D. | Athanassiou, G.

Article Type: Research Article

Abstract: Iodinated contrast media (CM) are widely used in diagnostic imaging and therapeutic interventional procedures of everyday clinical practice and are associated with multiple hemodynamic and hemorheological effects. The purpose of our work was to investigate the red blood cell (RBC) rheological properties after in vivo administration of low-osmolar or iso-osmolar CM by measuring their membrane deformability (Index of Rigidity, IR) using a filtration method. Blood samples were taken from patients who underwent digital subtraction angiography of the peripheral arteries at various times before and after intravenous administration of CM. CM included iso-osmolar Iodixanol, low-osmolar Iopromide and low-osmolar Iopentol. In the …whole patient group an IR increase of 59% was calculated 5 minutes after administration of CM followed by a normalization of elevated IR values within the following hour. The 5-min IR increase was strongest in the group treated with Iopromide, whereas administration of Iodixanol was associated with a more modest transient IR increase. Intravenous injection of CM in humans may be associated with a transient but considerable decrease of RBC membrane deformability and particularly for the iso-osmolar CM the induced changes in membrane deformability seem to be more moderate. Show more

Keywords: Iodinated contrast media, red blood cell, membrane, deformability, rheology, microcirculation

DOI: 10.3233/CH-2008-1071

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 87-91, 2008

Authors: Aydogan, Sami | Yapislar, Hande | Artis, Seda | Aydogan, Burcu

Article Type: Research Article

Abstract: Impaired red blood cell deformability is a hemorheological perturbation induced by many kinds of diseases. An increase in free radicals causes a reduction in erythrocyte flexibility and deformability. Carnosine is a dipeptide abundant in skeletal muscle and brain of humans. One of the main function of carnosine is its antioxidant and free-radical scavenger effect. In this study our aim is to investigate the protective effect of L-carnosine on RBCs in H2 O2 -induced oxidative stress in vitro conditions. Twenty male wistar albino rats, 10 were 3 months old, 10 were 12 months old used. The blood from each rat …were divided into ten tubes and these blood samples divided into two groups. The first tube of the first group was the control and the rest 4 tubes were treated with different concentrations of L-carnosine. All tubes in the second group were incubated with H2 O2 additively. The deformability indexes of the erythrocytes were measured by a laser diffractometer (Myrenne Rheodyne SSD). L-carnosine has improved the RBC deformability significantly which is impaired by H2 O2 treatment (p<0.05). Increase in deformability is more significant in young rat group when compared to old rat group. L-carnosine, as an antioxidant molecules, has a dose dependent positive effect on RBC deformability and has improved or protect the deformability of erythrocytes, especially in young rat group which impaired by H2 O2 -induced oxidative stress in vitro conditions. The results of this study first suggest that L-carnosine supplemention can be used to improve the RBC quality or to protect them from oxidative damage in survival of RBC in the circulation. Show more

Keywords: L-carnosine, erythrocytes deformability, oxidative stress, H_2O_2

DOI: 10.3233/CH-2008-1072

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 93-98, 2008

Authors: Birnbaum, J. | Lehmann, Ch. | Klotz, E. | Hein, O. Vargas | Blume, A. | Jubin, F. | Polze, N. | Luther, D. | Spies, C.D.

Article Type: Research Article

Abstract: Introduction: The study's objective was to determine the effects of the administration of N-acetylcysteine (NAC) and of tirilazad mesylate (TM) on intestinal functional capillary density, mesenteric plasma extravasation, leukocyte adherence and on cytokine release during experimental endotoxemia in rats. Methods: In a prospective, randomized, controlled animal study, 80 male Wistar rats were examined in 2 test series. Both series were divided into 4 groups. Group 1 served as control group (CON group). Group 2 (LPS group), group 3 (NAC group) and group 4 (TM group) received endotoxin infusions (10 mg/kg over 2 h). In NAC group 150 mg/kg body …weight NAC was administered after the first 30 minutes of endotoxemia intravenously. In TM group, 10 mg/kg body weight TM was administered after the first 30 minutes of endotoxemia intravenously. Animals of the series 1 underwent studies of leukocyte adherence on submucosal venular endothelium of the small bowel wall and intestinal functional capillary density (FCD) in the intestinal mucosa and the circular as well as the longitudinal muscle layer by intravital fluorescence microscopy (IVM). Plasma levels of interleukin 1β (IL-1β), interferone γ (IFN-γ) and soluble intercellular adhesion molecule1 (s-ICAM 1) as well as white blood cell count (WBC) were estimated. In the animals of the series 2 mesenteric plasma extravasation was determined by IVM and plasma levels of tumor necrosis factor α (TNF-α), IL-4, IL-6, IL-10 and malondialdehyde (MDA) were estimated. Results: After LPS administration, FCD in the villi intestinales was unchanged and in the longitudinal muscularis layer it was increased. There was no effect of NAC or TM administration on FCD. Although the plasma extravasation was not significantly influenced by LPS administration, TM administration resulted in a lower plasma extravasation in the TM group compared to the other groups. After endotoxin challenge, the firmly adherence of leukocytes to vascular endothelium as a parameter of leukocyte activation in endotoxemia was increased but NAC or TM administration had no influence on leukocyte adherence. The plasma levels of IL-1β, IL-6, IL-10, TNF-α, IFN-γ and sICAM-1 were increased in the endotoxemic groups (LPS group, NAC group and TM group) and the WBC was decreased compared to controls. IL-4 levels were unchanged during observation period. Plasma MDA levels were not influenced by LPS administration compared to controls. The administration of NAC resulted in lower sICAM-1 and MDA levels compared to the LPS group. The IL-1β, IL-6, IL-10, TNF-α and IFN-γ plasma levels were not influenced by NAC or TM administration. Conclusions: In this posttreatment sepsis model in rats, NAC administration resulted in lower sICAM-1 and MDA levels compared to the LPS treated animals. TM administration reduced the plasma extravasation in this model. Show more

Keywords: Endotoxin, rat, NAC, tirilazad mesylate, intravital microscopy, intestine, mesentery, perfusion, extravasation, sepsis, cytokines

DOI: 10.3233/CH-2008-1073

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 99-111, 2008

Authors: Cicha, Iwona | Goppelt-Struebe, Margarete | Yilmaz, Atilla | Daniel, Werner G. | Garlichs, Christoph D.

Article Type: Research Article

Abstract: Atherosclerosis results from a combination of local blood flow patterns and systemic risk factors. We investigated whether non-uniform shear stress at bifurcations induces pro-atherogenic endothelial dysfunction and monocyte recruitment. Bifurcating flow-through cell culture slides were used to expose HUVECs to laminar or non-uniform shear stress for 18 h at 10 dyne/cm2 . For the adhesion assay, HUVECs were subsequently perfused with medium containing THP-1 monocytes for 1 h. Protein expression was determined by immunofluorescence. In areas exposed to laminar shear stress, alignment of endothelial cells with the flow was observed, accompanied by upregulation of eNOS and downregulation of connective …tissue growth factor (CTGF). In contrast, cells exposed to non-uniform shear stress near the outer walls of bifurcations were characterized by irregular, unaligned shape, induction of endothelin-1 and CTGF, as well as reduced eNOS expression. These atherogenic effects of non-uniform shear stress were prevented when cells were treated with statins (1 μmol/l) during flow. Under non-uniform shear stress, a slight induction of VCAM-1, ICAM-1, and E-/P-selectin was observed. In agreement with this, monocyte recruitment, which was nearly undetectable under laminar shear stress, was moderately induced by non-uniform shear stress (P<0.02). In conclusion, inhibition of antioxidative eNOS and upregulation of atherogenic proteins is the first step in non-uniform shear stress-mediated endothelial dysfunction, which in vivo in the presence of atherogenic risk factors may further enhance monocyte recruitment into the artery wall. Show more

Keywords: Shear stress, endothelial dysfunction, monocyte adhesion, statins

DOI: 10.3233/CH-2008-1074

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 113-119, 2008

Authors: Clevert, D.-A. | Minaifar, N. | Weckbach, S. | Kopp, R. | Meimarakis, G. | Clevert, D.-A. | Reiser, M.

Article Type: Research Article

Abstract: The purpose of this study was to compare Color Duplex Ultrasound (CDU), Contrast-Enhanced Ultrasound (CEUS) and Multislice Computed Tomography (MS-CT) angiography in the routine follow up of patients following Endovascular Repair (EVAR) of Abdominal Aortic Aneurysm (AAA). 43 consecutive patients with AAA underwent endovascular aneurysm repair and were imaged with CDU, CEUS and MS-CT angiography at regular intervals after the procedure. Each imaging modality was evaluated for the detection of endoleaks. The presence of endoleaks was analyzed and the conspicuity of findings was assessed. CTA was used as gold standard in determining the presence of endoleaks. CDU was …true positive for endoleaks in 5/43 patients (11.6%) and false positive for endoleaks in 2/43 patients (4.6%). The sensitivity of CDU was therefore 33.3% and its specificity 92.8%; the positive and negative predictive values were 0.71 and 0.72, respectively. CEUS was true positive for the detection of endoleaks in 15/43 patients (34.9%) and false positive in 2/43 patients (4.6%). The sensitivity of CEUS was therefore 100% and its specificity 93%; the positive and negative predictive values were 0.88 and 1. In the follow up the two false positive endoleaks in CEUS were confirmed as true positive endoleaks by CEUS and MS-CT. In our small patient group, contrast-enhanced ultrasound seemed to be more accurately in demonstrating endoleaks after EVAR than MS-CT angiography and may be considered as a primary surveillance modality whereas duplex ultrasound scanning alone is not as sensitive as CEUS and MS-CT angiography in detection of endoleaks. Especially in patients with contraindications for CT contrast agents (e.g. due to renal failure or severe allergy) CEUS provides a good alternative to MS-CT. Show more

Keywords: Endoleak, contrast enhanced ultrasound, MS-CT, color duplex ultrasound

DOI: 10.3233/CH-2008-1075

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 121-132, 2008

Authors: Clevert, D.-A. | Graser, A. | Jung, E.M. | Stickel, M. | Reiser, M.

Article Type: Research Article

Abstract: Aneurysms of the extracranial carotid arteries are a rare abnormalitiy and may represent a diagnostic challenge in examination of the patients. B-flow is a new digital vascular ultrasound technique and is an especially reliable method in the diagnosis of the extracranial portion of the internal carotid arteries as it shows less flow artifacts than color-coded Doppler sonography (CCDS) and power Doppler (PD). This review compares color-coded Doppler sonography, power Doppler and B-flow findings in extracranial ICA and CA aneurysm to emphasize the usefulness of B-flow in this clinical condition.

Keywords: B-flow, extracranial carotid artery aneurysm, color-coded Doppler sonography, power Doppler

DOI: 10.3233/CH-2008-1076

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 133-146, 2008

Authors: Clevert, D.-A. | Stickel, M. | Kopp, R. | Weidenhagen, R. | Fink, C. | Jauch, K.W. | Reiser, M.

Article Type: Research Article

Abstract: We report the case of a 61-year-old patient admitted to our hospital owing to recent nonspecific abdominal pain. Five years earlier he had been treated with a graft owing to thoracic and abdominal aortic aneurysm with dissection. He now showed a left renal vein aneurysm with a diameter of 11×7.5 cm. This case demonstrates that contrast enhanced ultrasound (CEUS), employed in addition to computed tomography angiography, offers a promising new option for diagnosis and preoperative treatment planning in patients with abdominal vascular diseases. The results were compared with operative findings.

Keywords: Renal vein aneurysm, AV fistula, abdominal aortic aneurysm, contrast-enhanced ultrasound, abdominal aortic dissection

DOI: 10.3233/CH-2008-1077

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 147-154, 2008

Authors: Clevert, D.-A. | Weckbach, S. | Minaifar, N. | Clevert, D.-A. | Stickel, M. | Reiser, M.

Article Type: Research Article

Abstract: To evaluate the effectiveness of contrast-enhanced ultrasound (CEUS) in the diagnosis and characterization of hepatic, renal and splenic traumatic injuries versus conventional ultrasound (US) and multislice computed tomography (MS-CT). Between January 2005 and January 2007, 78 patients (48 males, 30 females, mean age 56 years) with blunt abdominal trauma were examined by conventional US, CEUS and MS-CT. CEUS employed a low-MI technique using 1.2 to 2.4 ml of SonoVue (Bracco, Italy) i.v. and a multifrequency transducer (2–4 MHz, Siemens, Sequoia, Acuson). CT examinations were performed on a 64 detector CT scanner (Somatom Sensation 16 or 64, Siemens Medical Systems, …Forchheim, Germany) before and after administration of 120 ml intravenous contrast agent (Solutrast® , Bracco, Milan, Italy) followed by 50 ml saline. The presence of hepatic, renal and splenic injuries was analyzed and the conspicuousness of findings was assessed. In 15 of the 78 patients conventional US identified solid organ injuries: 8 hepatic, 2 renal and 5 splenic injuries. CEUS identified 3 more injuries (2 hepatic and 1 splenic) that had been missed by conventional US. CEUS identified traumatic lesions in 18/78 patients. In one of the 18 patients even active bleeding could be identified by CEUS. In CEUS solid organ injuries appeared hypoechoic. MS-CT identified 18 solid organ injuries in 78 patients, corroborating the CEUS results. CEUS greatly improves the visualization and characterization of hepatic, renal and splenic injuries compared to conventional ultrasound and correlates well with MS-CT. The imaging technique detects even minor blood flow and is able to depict vascular structures in detail. At our institution it is used as an additional examination technique which supplements MS-CT in unclear cases. Owing to its bedside availability, CEUS provides a good alternative to MS-CT, especially in patients with contraindications to CT contrast agents (e.g. due to renal failure or severe allergy) and in hemodynamically compromised patients. Show more

Keywords: Trauma, contrast-enhanced ultrasound, multislice computed tomography

DOI: 10.3233/CH-2008-1080

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 155-169, 2008