Clinical Hemorheology and Microcirculation - Volume 17, issue 2

Authors: London, Morris

Article Type: Research Article

Abstract: Review of the role of blood rheology in regulating blood pressure discloses that macromolecular binding to the erythrocyte membrane is a significant factor. Evidence is summarized supporting the thesis that blood viscosity is a prime regulator of blood pressure. Macromolecules may bind to erythrocytes and other macromolecules forming structures that increase blood viscosity when the blood stream flow rate is decreased. Review of the nature and extent of RBC membrane binding and a model for relating these bonds to blood pressure are presented.

Citation: Clinical Hemorheology and Microcirculation, vol. 17, no. 2, pp. 93-106, 1997

Authors: Aggelopoulos, E.G. | Karabetsos, E. | Koutsouris, D.

Article Type: Research Article

Abstract: Aggregation of red blood cells (RBCs) is one of the principal hemorheological factors which plays an important role in capillary circulation. In order to study RBC’s aggregation, an ultrasound Doppler in vitro technique, using pulsed wave monoelement pencil 4 MHz probes, was designed. A hydraulic pump system has been implemented, using an electric step motor that establishes in a certain distance, a laminar blood flow profile into a rectangular cross‐section plexiglass tube. Blood coming from blood collection bags was used and following certain typical measuring protocols, red blood cells’ samples of various parameters and conditions were acquired. Adding dextrans to …the blood samples, red blood cells aggregation was achieved and observed for various hematocrit values. Both the emitted and the backscattered signals were driven to a system containing a multi‐channel digital oscilloscope – of high sampling rate and processing capabilities – and a powerful PC with a high acquisition A/D card and special control software. The estimation of mean aggregates size – by measuring the mean ultrasonic intensity scattered by the blood sample – led us to a qualitative, in vitro ultrasonic method. Show more

Keywords: Erythrocyte aggregation, PW Doppler ultrasound, in vitro

Citation: Clinical Hemorheology and Microcirculation, vol. 17, no. 2, pp. 107-115, 1997

Authors: Toth, K. | Bogar, L. | Juricskay, I. | Keltai, M. | Yusuf, S. | Haywood, L.J. | Meiselman, H.J.

Article Type: Research Article

Abstract: This study evaluated the hemorheological effects of a nonionic block copolymer surfactant, RheothRx Injection, on the hemorheological parameters in patients with acute myocardial infarction (AMI). For the in vitro study blood from 24 patients admitted with chest pains (mean age: 49 \pm 11 yrs) was sampled after admission and in AMI cases (15 patients, mean age: 53 \pm 13 yrs) a second sample was collected 48 hours later. Different concentrations of RheothRx were added (0.25, 0.5, 1, 2 and 5 mg/ml) and the blood was tested for RBC aggregation via our computerized Myrenne Aggregometer (at Hct …= 40%). Besides other routine laboratory parameters, fibrinogen levels were measured. In a substudy for CORE Trial, the hemorheological effects of RheothRx infusion was studied. Seven patients (mean age: 63 \pm 13 yrs) admitted with AMI and randomized for CORE Trial were studied. The samples were collected after admission, at 12, 24, 48 hours, and at day 8 and 35. In vitro we found a significant (p < 0.05 or better) concentration‐related decrease of RBC aggregation from 0.5 mg/ml drug concentration in the admission (both groups) and in the 48 hour (AMI) samples, in AMI patients with a mean decrease of 7 and 5% at 0.5 mg/ml, 13 and 8% at 1 mg/ml, 22 and 19% at 2 mg/ml and 39 and 33% at 5 mg/ml plasma concentration of the drug. In the CORE Trial patients hemorheological parameters (plasma and whole blood viscosity, RBC aggregation and fibrinogen level) decreased during and after the administration of RheothRx, but after 2–8 days their values returned to the baseline level. These findings indicate that this agent can significantly reduce RBC aggregation and other hemorheological parameters, and thus suggest its potential usefulness in clinical states associated with increased RBC aggregation. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 17, no. 2, pp. 117-125, 1997

Authors: Caimi, Gregorio | Assennato, Pasquale | Canino, Baldassare | Montana, Maria | Ventimiglia, Giuseppe | Lo Presti, Rosalia

Article Type: Research Article

Abstract: We evaluated, during an exercise test, the leukocyte flow properties, the polymorphonuclear leukocyte (PMN) membrane fluidity and PMN cytosolic Ca^{2+} content in normals, in subjects with previous acute myocardial infarction (AMI) and in subjects previously submitted to a aortocoronary by‐pass. Leukocyte flow properties were evaluated using the St.George filtrometer. Examination of the PMN membrane fluidity was effected employing the probe TMA‐DPH; while evaluation of the PMN cytosolic Ca^{2+} content was carried out using the probe Fura 2‐AM. At baseline, in both cardiopathic groups a significant difference in PMN filtration parameters and in PMN cytosolic Ca^{2+} …content was evident compared to normals. In normals, at peak of exercise, there was an evident reduction of mononuclear filtration parameters, while during recovery a slight increase of the PMN cytosolic Ca^{2+} content was observed. In subjects with previous AMI and in subjects with aortocoronary by‐pass, however, we observed, at peak of exercise, a decrease of the mononuclear filtration parameters, a reduction of the PMN membrane fluidity and an increase of the PMN cytosolic Ca^{2+} content. In both groups, the changes in PMN membrane fluidity and cytosolic Ca^{2+} content remained during recovery. The trend of the PMN membrane fluidity and cytosolic Ca^{2+} content found in the cardiopathic subjects during the exercise test suggest that PMN activation may be more evident in these subjects. Show more

Keywords: Acute myocardial infarction, aortocoronary by‐pass, exercise test, leukocyte rheology, PMN membrane fluidity, PMN cytosolic Ca^{2+}

Citation: Clinical Hemorheology and Microcirculation, vol. 17, no. 2, pp. 127-135, 1997

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 17, no. 2, pp. 137-171, 1997

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 17, no. 2, pp. 173-173, 1997