Clinical Hemorheology and Microcirculation - Volume 27, issue 2

Authors: Capecchi, P.L. | Guideri, F. | Colafati, M. | Acampa, M. | Cuomo, A. | Lazzerini, P.E. | Pasini, F. Laghi

Article Type: Research Article

Abstract: Three episodes of 1 min ischemia in the lower limbs in humans reduced the metabolic debt repayment (expressed as AUC of reactive hyperaemia) following more prolonged ischemia (666.6±86.6 vs 500.0±33.5 ml/100 ml). The administration of the ATP‐dependent K+ channel blocker glibenclamide was associated with a significant reduction in the AUC of reactive hyperaemia (666.6±86.6 vs 563.1±76.6 ml/100 ml), and with the removal of the protective effect produced by 3 episodes of 1 min ischemia (563.1±76.6 vs 551.8±71.3 ml/100 ml). Plasma level of glibenclamide reached the peak value of 1.295±0.15 μmol/l 2 h after drug administration, ranging around the 1 …μmol/l concentration in the following 3 hours. Our findings produce indirect evidence that, similarly to the ischemic preconditioning of the heart, the protective effects towards ischemia of brief repeated episodes of sub‐maximal occlusion in the peripheral circulation of the lower limbs in humans are mediated by ATP‐dependent K+ channels. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 77-82, 2002

Authors: Caimi, G. | Montana, M. | Citarrella, R. | Porretto, F. | Catania, A. | Lo Presti, R.

Article Type: Research Article

Abstract: We examined the polymorphonuclear leukocyte (PMN) integrin pattern in 45 diabetic subjects without macrovascular complications, including 21 subjects with type 1 and 24 with type 2 diabetes mellitus. The PMN adhesion molecules (CD11a, CD11b, CD11c, CD18) were evaluated using indirect immunofluorescence and a flow cytometer, at baseline and after in vitro activation with 4‐phorbol 12‐myristate 13‐acetate (PMA) and N‐formyl‐methionyl‐leucyl‐phenyl‐alanine (fMLP). At baseline, in diabetic subjects the phenotypical expression of CD11a and CD11b was significantly reduced and CD11c was increased, whereas CD18 was unchanged in comparison with normals. Considering type 1 and 2 diabetic subjects separately, CD11a was reduced and CD11c …was increased in both subgroups, CD11b was decreased only in type 1 diabetics and CD18, decreased in type 1, was increased in type 2 subjects. After activation with PMA and fMLP, in normal subjects we observed a significant increase of all PMN adhesion molecules whereas in diabetic subjects only CD11c increased significantly with both activating agents, and CD11b increased only after PMA activation. In type 1 diabetic subjects only CD11c expression was increased, and in type 2 diabetic subjects an increase of CD11b (with PMA) and an increase of CD11c (with fMLP) were noted. In conclusion, we found in diabetic subjects of type 1 and 2 an altered behaviour pattern of PMN integrins both at baseline and, in particular, after in vitro activation. These data may help in explaining the role of PMN in the evolution of diabetic vascular complications. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 83-89, 2002

Authors: Manjunatha, M. | Singh, Megha

Article Type: Research Article

Abstract: Blood flow through frog mesenteric microvessel with multiple branching, at Reynolds number 0.022, is analyzed. After pre‐processing the images the velocity and erythrocyte distribution profiles by image velocimetry and axial tomography are obtained, respectively. The vascular parameters and shape descriptors are obtained by image processing techniques. The axial velocity shows the variation around branching areas associated with an increase in radial velocity, which is up to 10% of axial velocity. From the erythrocyte distribution profiles at various locations in the microvessel the tomograms are reconstructed. Based on these the contours of equal concentration are reconstructed. From these contours the point‐to‐point …variation in cell concentration throughout the microvessel is observed and regions where the cellular concentration varies from 3 to 5%, at zero axial velocity, are identified. The change in erythrocyte shape, determined by the shape descriptors, while passing through the capillary is significant. This passage of cells, depending on their orientation, also displaces the capillary walls by 1.5 to 2.5 μm. Show more

Keywords: Frog mesenteric microvessel, axial tomography, image velocimetry, erythrocyte shape descriptors

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 91-106, 2002

Authors: Konukoglu, D. | Ercan, M. | Hatemi, H.

Article Type: Research Article

Abstract: Hypothyroidism is associated with atherosclerotic events, however, the mechanism is unclear. We investigated the effects of oxidative stress and cholesterol on plasma viscosity in female patients with hypothyroidism (n=20; mean age: 45.5±5.5 years) at baseline and after L‐thyroxine replacement therapy (average daily dose being 0.1 to 0.15 mg). Two blood samples were taken after 2.3±1.2 months. In hypothyroid state plasma viscosity and thiobarbituric acid reactive substance (TBARS; marker of oxidative stress were significantly higher (p<0.001 and p<0.001), and plasma protein thiol (antioxidants) levels were significantly lower (p<0.001) than in the healthy state (female; n=15). After L‐thyroxine replacement therapy, patients reached …to euthyroid state. In this state, the levels of plasma viscosity and TBARS were decreased (p<0.001 and p<0.001), and protein thiol levels were significantly elevated (p<0.001). There was a significant correlation between plasma cholesterol and viscosity (r=0.64, p<0.001), as well as plasma protein thiol (r=−0.59, p<0.001) in the patients. The correlation between viscosity and TBARS was weak (r=0.29, p<0.01). Therefore hypothyroidism may be associated with atherosclerotic process by different mechanisms. Show more

Keywords: Atherosclerosis, hypothyroidism, lipid peroxidation, oxidative stress, plasma viscosity, thiol

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 107-113, 2002

Authors: Gaudard, A. | Varlet‐Marie, E. | Monnier, J.F. | Janbon, Ch. | Quéré, I. | Bressolle, F. | Brun, J.‐F.

Article Type: Research Article

Abstract: Exercise‐induced impairment in blood fluidity has been supposed to increase cardiovascular risk but there is no data to support this hypothesis. We report the case of a 50 yr old marathon runner who underwent a central retinal vein thrombosis after a marathon run. We investigated his rheological response to exercise compared to control subjects of previous studies. During a standardized sub‐maximal exercise‐test, the increase in blood viscosity (+28%) and hematocrit (+25%) exceeded the control range but the most striking differences were found for red cell aggregation (Myrenne +47%) and disaggregation thresholds (Affibio +37%). Although some of this post‐exercise hyperviscosity pattern …may be due to the previous vascular event, these findings may also support the hypothesis of a role for hemorheological alterations during exercise in the pathogenesis of this marathon‐induced retinal thrombosis, and indicate that after such an event hemorheological adaptation to exercise remains markedly disturbed. Show more

Keywords: Blood viscosity, plasma viscosity, exercise, hemorheology, retinal vein occlusion, case report, eye injuries, human, male

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 115-122, 2002

Authors: Karsch, Uwe | Henn, Wolfram | Seyfert, Ulrich Theo | Steudel, Wolf‐Ingo | Reif, Johannes

Article Type: Research Article

Abstract: Objective: The goal of this study was to develop an in vitro model system in which the hemostatic effects of high power ultrasound applied to the outer surface of blood vessels during tumor dissection can be simulated and measured. Methods: Monolayers of endothelial cells (HUVEC, ATCC) in cell culture plates were sonicated with an ultrasound dissector (SONOCA II, Soering) at a frequency of 23.5 kHz. The dissector was equipped with a cooling circuit. The cell cultures were exposed to 2 minutes of continuous ultrasound with intensities of 10, 50, or 100 W/cm2 . To differentiate between heat and sound effects, …selected monolayers were warmed for 2 minutes. Finally, the cell cultures were stained with trypan blue to assess for cell death due to membrane disruption. Cytomorphological alterations and changes in the concentration of coagulation parameters in the cell culture medium were evaluated. Results: The cytomorphological alterations were found to depend on ultrasound intensity. They included detachment of single endothelial cells, cell cluster formation and cytoplasmic cavitation. Disruption of the cell membrane integrity was infrequently observed. Of 14 screened coagulation parameters, thromboxane B2 (TXB2 ), prostaglandin F1α (PGF1α ), plasminogen activator inhibitor type 1 (PAI‐1), thrombomodulin (TM), and thrombospondin (TSP) were found to be ultrasound sensitive. TXB2 concentrations in the medium increased beginning at low ultrasound intensities (p<0.01) and were independent of temperature. PGF1α concentrations peaked at high ultrasound intensities (p<0.05), and heat alone produced a significant increase in concentration (p<0.05). At high intensities, the ratio of TXB2 to PGF1α shifted in favour of PGF1α . PAI‐1 was most strongly secreted at low ultrasound intensities (p<0.01), and heat resulted in a decrease of concentration (p<0.05). TM and TSP concentrations correlated strongly and reached a non significant peak at low intensities. Conclusion: The results demonstrate that during sonication of endothelial cells in vitro, coagulation parameters are released from distant undamaged cells. HUVEC‐cells exhibit a differential hemostaseological response at different ultrasound intensities, and the response is also influenced by heat. Additionally, massive morphological damage can be induced at the endothelium. Show more

Keywords: Coagulation parameters, cytoplasmic cavitation, endothelial lesions, heat, HUVEC, ultrasound dissection

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 123-135, 2002

Authors: Mesquita, Rui | Piçarra, Bruno | Saldanha, Carlota | Martins e Silva, J.

Article Type: Research Article

Abstract: NO is present in the blood at 10−7 M under physiological conditions, but at concentrations higher than 10−6 M during inflammatory disease states. The aim of this study was to characterize what are the effects of these different NO concentrations on erythrocyte structural and functional properties. Blood was collected from eleven healthy men and incubated with SpermineNONOate in order to expose it during incubation time to NO concentrations between 10−7 M and 10−3 M. We measured erythrocyte aggregation and deformability, membrane lipid peroxidation and fluidity, p50, hemoglobin, oxyhemoglobin, methemoglobin concentrations and plasma pH, pO2 , pCO2 …, Na+ , K+ and Ca2+ . When blood was exposed to NO 10−7 M erythrocyte deformability increase and p50 decrease. In presence of NO 10−5 M lipid fluidity and p50 decrease. When blood was exposed to NO 10−3 M methemoglobin concentration increase and erythrocyte deformability and p50 decrease but membrane fluidity and lipid peroxidation were similar to control. In conclusion, dependent of NO concentrations there is different effects on erythrocytes structural and functional properties. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 137-147, 2002

Authors: Bogar, L. | Tarsoly, P. | Jakso, P.

Article Type: Research Article

Abstract: Whole blood gravity sedimentation technique can be modified for studying leukocyte sedimentation properties. Previously, we demonstrated that the displacement rate of leukocytes was associated with activation of leukocytes during traditional gravity sedimentation of the whole blood. The plasma flow as well as the difference between the specific gravity of leukocytes and plasma propel the leukocytes upward in the sedimentation tube while the erythrocyte aggregates are descending. The leukocyte ascension rate can be described as the increment of leukocyte concentration in the upper half section of the blood column after one‐hour sedimentation. The aim of the present study was to characterize …the ascending and non‐ascending leukocytes using a flow cytometric technique. Venous blood samples were taken from 8 healthy controls and 8 septic patients after major thoracic or abdominal surgical procedures. The upper and lower halves sections of venous blood column were separately removed from the sedimentation tube after one hour gravity sedimentation. Using flow cytometry, the leukocyte subsets were identified by their CD45 density and side scatter parameters followed by characterization of their cellular size and cytoplasmic granularity. The size indices of septic patients' ascending polymorphonuclear leukocytes (PMNs) were significantly lower than that of the non‐ascending ones (253±22 versus 387±12 (SEM), p<0.002) or the ascending PMN fraction taken from healthy individuals (382±28, p<0.005). Septic patients' ascending PMNs presented significantly lower cytoplasmic granularity indices compared to non‐ascending (447±23 versus 538±18, p<0.05) or healthy ascending PMNs (539±20, p<0.05). The cellular size and cytoplasmic granularity indices of heavy and light monocytes as well as lymphocytes were similar in both groups. It can be assumed that venous blood samples of septic patients contain significantly smaller PMNs with less cytoplasmic granularity than healthy control cells. Show more

Keywords: Sedimentation, flow cytometry, polymorphonuclear leukocytes, monocytes, lymphocytes, cellular size, cytoplasmic granularity

Citation: Clinical Hemorheology and Microcirculation, vol. 27, no. 2, pp. 149-153, 2002