Clinical Hemorheology and Microcirculation - Volume 38, issue 4

Authors: Erdem, T.Y. | Ercan, M. | Ugurlu, S. | Balcı, H. | Acbay, O. | Gundogdu, S.

Article Type: Research Article

Abstract: Objective: It is controversial, if subclinical hypothyroidism increases cardiovascular risk. Plasma viscosity is a hemorheological parameter, which is accepted as an early cardiovascular risk factor. We investigated the alterations in plasma viscosity in women with subclinical hypothyroidism. Design: 40 female patients with subclinical hypothyroidism and 31 age- and weight-matched healthy women were included. Free thyroxine (FT4), thyroid stimulating hormone (TSH), lipid parameters, fibrinogen, C-reactive protein (CRP) levels, hematocrit and plasma viscosity were measured in all subjects. Main outcome: Plasma viscosity, total cholesterol and low density lipoprotein were significantly increased and high density lipoprotein was significantly decreased in patients with subclinical …hypothyroidism. No significant correlation was found among the parameters. Conclusion: Increased plasma viscosity in patients' group suggests that cardiovascular risk might be increased in patients with subclinical hypothyroidism. As far as we could reach, this is the first study concerning plasma viscosity in subclinical hypothyroidism. Show more

Keywords: Plasma viscosity, subclinical hypothyroidism, cardiovascular risk factors

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 219-225, 2008

Authors: Ercan, M. | Konukoglu, D.

Article Type: Research Article

Abstract: Obesity is associated with atherosclerotic risk factors, including reduced blood flow, endothelial dysfunction, lipid disorders and hyperinsulinemia. In recent years, several studies have demonstrated that elevated homocysteine is a risk factor for atherosclerosis. This study was aimed at determining whether any relationship between plasma viscosity and homocysteine levels in patients with normo and hyperinsulinemic obese patients. Obese women (n=75) and healthy, age-matched non-obese women (n=70) was included in our study. Plasma viscosity, tHcy, insulin level, total-C, LDL-C, HDL-C, triglyceride and glucose level were significantly higher in obese subjects than in non-obese subjects. Obese subjects were also divided into two groups, …according to the basal insulin levels as normo and hyper insulinemic. Hyperinsulinemic obese subjects had significantly higher PV level compared with normoinsulinemic subjects. When correlation analyses were performed normoinsulinemic obese subjects, significant correlations were found between PV and total-C (r: 0.776) and insulin level (r: 0.752), BMI (r: 0.580), HOMA-IR (r: 0.510). PV was positively correlated with total-C (r: 0.485), insulin level (r: 0.624), BMI (r: 0.624) and HOMA-IR ratio (r: 0.707), in hyperinsulinemic obese subjects. Hcy was positively correlated BMI in both groups. In conclusion that, it is point out that elevated homocysteine and increased PV are two factors that may act separately and probably do not affect each other. Show more

Keywords: Plasma viscosity, homocysteine, obesity, hyperinsulinemia

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 227-234, 2008

Authors: Kasiyaphat, Atchareeya | Siriviriyakul, Prasong | Patumraj, Suthiluk

Article Type: Research Article

Abstract: This study was aimed to examine effects of genistein on leukocyte adhesion in femur microcirculation in relation to bone-loss induced in ovariectomized female rats. Sixty-four female Wistar rats were divided into 4 groups: sham (daily treated with vehicle; DMSO, sc; 100 μl/day), ovariectomized rat treated with vehicle (OVXveh ), 17β-estradiol treated-ovariectomized rat (OVXE2 , 5 μg/kg/day, sc) and genistein treated-ovariectomized rat (0.25 mg/kg/day, sc; OVXgen ). One and three weeks after the ovariectomy, blood flow perfusion (BF) in femur tissue was measured using laser Doppler flowmetry. Leukocyte adhesion in femur venules (15–30 μm in diameter) of each group was evaluated …by intravital fluorescence videomicroscopy. The bone mineral content (BMC) was measured and expressed in terms of ratio of ash-to-dry matter weight. Serum osteocalcin and alkaline phosphatase levels were determined using chemiluminescence immunoassay. In both one and three week-OVXveh , leukocyte adhesion increased significantly, compared to their age-matched sham groups, but it decreased significantly in OVXgen , compared to OVXveh (p<0.05). In three week-OVXgen , both BF and BMC increased significantly, but osteocalcin and alkaline phosphatase levels decreased, compared to those of three week-OVXveh . In conclusion, genistein supplementation could effectively prevent bone-loss and microvascular endothelial dysfunction induced by estrogen deficiency. Show more

Keywords: Genistein, leukocyte adhesion, bone blood flow perfusion, bone loss, ovariectomized rat

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 235-243, 2008

Authors: Sakai, Jiro | Karino, Takeshi | Niwa, Koichi

Article Type: Research Article

Abstract: To elucidate the roles of blood flow and transmural filtration flow in localized LDL accumulation in vascular walls, we studied the effects of flow velocity on LDL concentration at the cell surface and LDL uptake by co-cultures of vascular endothelial cells (ECs) and smooth muscle cells using a parallel-plate flow cell with or without filtration flow. Co-cultures were prepared on porous membranes. In the presence of filtration flow through the cell layer, the LDL concentration at the cell surface increased when the perfusion velocity was decreased (shear stress was decreased from 1.5 to 0.2 Pa). In the absence of filtration …flow, LDL concentration remained unchanged despite changes in flow velocity. LDL uptake by the cells was proportional to its surface concentration that varied inversely with flow velocity. Therefore, in the presence of filtration flow, LDL accumulation was greater under conditions of low shear stress (0.2 Pa) than with high shear stress (1.5 Pa). In contrast, in the absence of filtration flow, LDL uptake was almost proportional to the magnitude of shear stress. These results suggest that shear stress-induced biological responses of ECs and transmural filtration flow, both play important roles in localized LDL accumulation in vascular walls. Show more

Keywords: LDL, filtration flow, vascular walls, shear stress, atherosclerosis

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 245-256, 2008

Authors: Connes, Philippe | Hue, Olivier | Hardy-Dessources, Marie-Dominique | Boucher, John H. | Pichot, Vincent | Barthélémy, Jean-Claude

Article Type: Research Article

Abstract: The aim of the present study was to test the relationships between hemorheology and autonomic nervous system (ANS) activity in 23 sickle cell trait (SCT) carriers and 17 control subjects. Hemorheological parameters were assessed at rest. Nocturnal ANS activity was calculated from heart rate variability indices. Impairment was observed in both domains in SCT carriers as they showed higher blood viscosity, higher red blood cell rigidity and a lower index of oxygen supply to tissues, as well as lower ANS activity. The index of oxygen supply to tissues was positively correlated with some of the indices of parasympathetic activity and …global ANS activity. Negative correlations were found between blood viscosity and the very low frequency of the spectrum (VLF) that contains partial parasympathetic activity and between red blood cell rigidity and the percentage of differences between adjacent normal RR intervals more than 50 ms (PNN50), which also describes parasympathetic activity. These results support the hypothesis that autonomic nervous system equilibrium is affected by perturbations in blood rheology. Mechanisms have yet to be elucidated. Show more

Keywords: Blood viscosity, red blood cell rigidity, autonomic nervous system activity, heart rate variability, parasympathetic activity

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 257-265, 2008

Authors: Evans, P.A. | Hawkins, K. | Lawrence, M. | Barrow, M.S. | Williams, P.R. | Williams, R.L.

Article Type: Research Article

Abstract: We report studies of the coagulation of samples of whole human blood by oscillatory shear techniques, including Fourier Transform Mechanical Spectroscopy (FTMS). These techniques are used herein to identify the Gel Point of coagulating blood in terms of the Chambon–Winter Gel Point criterion which provides a rheometrical basis for detecting the establishment of an incipient clot. A comparison of the results of FTMS with those obtained from measurements involving a Thromboelastograph (TEG) and a Free Oscillation Rheometer (FOR) indicate that the latter techniques are not capable of detecting the incipient clot, whose establishment occurs several minutes prior to TEG or …FOR-based assessments of clot formation time. The results of the present study suggest that FTMS is a useful tool in blood clotting research, being capable of providing a global coagulation profile in addition to detecting the instant of incipient clot formation. Show more

Keywords: Incipient blood clot, gel point, clotting time, clot microstructure, fractal dimension

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 267-277, 2008

Authors: Häfner, Hans-Martin | Schmid, Ute | Moehrle, Matthias | Strölin, Anke | Breuninger, Helmut

Article Type: Research Article

Abstract: Vascular effects of local anesthetics are especially important in dermatological surgery. In particular, adequate perfusion must be ensured in order to offset surgical manipulations during surgical interventions at the acra. However, the use of adrenaline additives appears fraught with problems when anesthesia affects the terminal vascular system, particularly during interventions at the fingers, toes, penis, outer ears, and tip of the nose. We studied skin blood flux at the fingerpads via laser Doppler flowmetry over the course of 24 hours in a prospective, double-blind, randomized, placebo-controlled study with 20 vascularly healthy test persons following Oberst's-method anesthetic blocks. In each …case, 6 ml ropivacaine (7.5 mg/ml) (A), lidocaine 1% without an additive (B), and lidocaine 1% with an adrenaline additive (1:200,000) (C) was used respectively as a verum. Isotonic saline solution was injected as a placebo (D). Measurements were carried out with the aid of a computer simultaneously at D II and D IV on both hands. Administration of (A) led to increased blood flux (+155.2%); of (B) initially to a decrease of 27%; of (C) to a reduction of 55% which was reversible after 40 minutes and of (D) to no change. (A) resulted in sustained vasodilatation which was still demonstrable after 24 h. (B) had notably less vasodilative effect, although comparison with (D) clearly showed that (B) is indeed vasodilative. (C) resulted in only a passing decrease in perfusion; this was no longer measurable when checked after 6 and 24 h. This transient inadequacy of blood flux also appeared after administration of (D). These tests show that adrenaline additive in local anesthesia does not decrease blood flow more than 55% for a period of 16 min. Following these results an adrenaline additive can be safely used for anesthetic blocks at the acra in healthy persons. Show more

Keywords: Local anesthesia, finger, adrenaline, blood perfusion

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 279-288, 2008

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 4, pp. 289-293, 2008