Clinical Hemorheology and Microcirculation - Volume 17, issue 4
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Clinical Hemorheology and Microcirculation, a peer-reviewed international scientific journal, serves as an aid to understanding the flow properties of blood and the relationship to normal and abnormal physiology. The rapidly expanding science of hemorheology concerns blood, its components and the blood vessels with which blood interacts. It includes perihemorheology, i.e., the rheology of fluid and structures in the perivascular and interstitial spaces as well as the lymphatic system. The clinical aspects include pathogenesis, symptomatology and diagnostic methods, and the fields of prophylaxis and therapy in all branches of medicine and surgery, pharmacology and drug research.
The endeavour of the Editors-in-Chief and publishers of
Clinical Hemorheology and Microcirculation is to bring together contributions from those working in various fields related to blood flow all over the world. The editors of
Clinical Hemorheology and Microcirculation are from those countries in Europe, Asia, Australia and America where appreciable work in clinical hemorheology and microcirculation is being carried out. Each editor takes responsibility to decide on the acceptance of a manuscript. He is required to have the manuscript appraised by two referees and may be one of them himself. The executive editorial office, to which the manuscripts have been submitted, is responsible for rapid handling of the reviewing process.
Clinical Hemorheology and Microcirculation accepts original papers, brief communications, mini-reports and letters to the Editors-in-Chief. Review articles, providing general views and new insights into related subjects, are regularly invited by the Editors-in-Chief. Proceedings of international and national conferences on clinical hemorheology (in original form or as abstracts) complete the range of editorial features.
The following professionals and institutions will benefit most from subscribing to
Clinical Hemorheology and Microcirculation: medical practitioners in all fields including hematology, cardiology, geriatrics, angiology, surgery, obstetrics and gynecology, ophthalmology, otology, and neurology. Pharmacologists, clinical laboratories, blood transfusion centres, manufacturing firms producing diagnostic instruments, and the pharmaceutical industry will also benefit.
Important new topics will increasingly claim more pages of
Clinical Hemorheology and Microcirculation: the role of hemorheological and microcirculatory disturbances for epidemiology and prognosis, in particular regarding cardiovascular disorders, as well as its significance in the field of geriatrics. Authors and readers are invited to contact the editors for specific information or to make suggestions.
Abstract: The application of principles of hemorheology on a process of blood coagulation was suggested by H.H. Hartert – inventor of the thromboelastograph which he introduced in 1947. These principles of applying of a mechanical force and detecting the response of coagulating blood enable to determine a functional evidence of the physiological process producing a hemostatic clot. The thromboelastography, as well as other rheological techniques used for this determination, are introduced evaluating the process in terms of the rate of coagulation, clot elasticity, deformability and permeability. Recent applications of the techniques to the diagnosis of disorders of hemostasis and the study…of drug effects on coagulation are presented as well.
Abstract: We compared blood viscosity and red blood cells (RBC) disaggregation shear stress in three mammalian species (humans, pigs and sheep) before and after adding water‐soluble iodinated contrast media (CM): Ioxaglate (ionic CM) and Iopromide (non ionic CM). The two CMs had a diluting effect on the blood of the three species, which resulted in a viscosity decrease at all shear rates. However, viscosity rose slightly at low shear rates (in relation to increase of RBC aggregation) and low CM concentrations (10%), regardless of the ionic or non ionic nature of the CM. The two CMs had a similar proaggregant effect…in human and pig’s bloods. The proaggregant effect was slightly more pronounced with the ionic CM. We concluded that the pig is more suitable than the sheep for in vivo assessment of blood/CM mixture.
Abstract: It has been reported that some rheologic abnormalities are associated with diabetes. However, it is difficult to realize the condition of microcirculation in men. We developed an intra‐vital video‐microscopic system (IVVMS) to observe microcirculation directly on the bulbar conjunctiva. Using this system, we investigated the effect of intravenous glucagon administration on microcirculatory parameters such as the internal diameter of venules, flow velocity and flow volumes in diabetic patients. Blood viscosity and rheology factors were also examined before and after glucagon administration. The time required for erythrocytes to pass through pores of 5 \mu m diameter, as well as whole…blood viscosity were decreased significantly after glucagon administration. Flow volumes of venules were increased significantly by glucagon. Leukocyte counts, platelet counts and fibrinogen did not change after glucagon administration. However, plasma glucose, insulin, C‐peptide and cyclic‐AMP were increased. In conclusion, glucagon administration improved blood fluidity and modified the microcirculation in patients with diabetes mellitus.
Abstract: Membrane and whole red cell deformability are essential for effective blood flow, oxygen uptake and release. Whole cell deformability (rheoscope with shear stresses of 0.6–30 Pa) and membrane shear elastic modulus (flow channel) of red blood cells (RBC) were studied in appropriate and small for gestational age preterm infants (28–32 wk of gestation), in healthy full‐term neonates and in adults. No significant differences were found between the two groups of preterm infants. The preterm infants showed significantly increased RBC deformation in the rheoscope when compared to the full‐term neonates who, in turn, showed more RBC deformation than adults. Correspondingly, the…membrane shear elastic modulus (i.e., the resistance to elastic membrane deformation) was lower in the preterm infants than in the full‐term neonates and lower in full‐term infants than in adults. Thus, both whole cell and membrane deformability appear to be increased in preterm infants. Improved RBC deformability may aid in the maintenance of adequate blood circulation in preterm infants in spite of low vascular pressures.
Keywords: Circulation, erythrocyte deformability, erythrocyte membrane, preterm infants, small‐for‐gestational age
Abstract: Blood rheological properties were examined in patients before, during and after neurosurgical operations of arterial aneurisms, as well as in patients where no operation was carried out, and in healthy volunteers. Erythrocyte aggregability was quantified by using the “Georgian technique” and compared with other indices of blood rheological disorders. Prior to the operations the erythrocyte aggregability did not differ significantly in both healthy probands and neurosurgical patients. In the course of surgery the index increased gradually and became almost two times higher than before operation in the same patients. Evidence was obtained that this effect was accounted for the mannitol…administration, since in the control cases, without operations, its infusion into the circulation produced a comparable increase of the aggregability. Other indices of hemorheological disorders did manifest no regular and significant changes in the same patients. The enhanced erythrocyte aggregability might be a factor disturbing to a degree the blood rheological properties in cerebral microvessels of neurosurgical patients operated with mannitol.
Keywords: Neurosurgical operations of arterial aneurisms, hemorheological disorders, effect of mannitol, erythrocyte aggregability, effect of mannitol, mannitol and hemorheological disorders
Abstract: In the present study, we investigate the effect of glutaraldehyde incorporation on the erythrocyte deformability, membrane fluidity and process of molecular oxygen diffusion. The erythrocyte deformability variations were inversely related with the glutaraldehyde concentration incorporated. The membrane fluidity, as assessed by a method based on the kinetics of pyrene dodecanoic acid excimers formation, decreased as the glutaraldehyde concentration increased. So, we verified that glutaraldehyde incorporation was accompanied by membrane rigidification. In the presence of glutaraldehyde, decreased absorption of hemoglobin heme group (420 nm) and decreased hemoglobin‐dependent quenching of pyrene butyric acid (PBA) fluorescence would result from hemoglobin polymerization. Using a…technique of fluorescence intensity quenching by molecular oxygen (accessibility to oxygen), we showed that oxygen diffusion was decreased in the presence of glutaraldehyde. To conclude, membrane rigidification induced by glutaraldehyde incorporation would affect oxygen molecular process.
Abstract: There is a need for quality assurance procedures in hemorheology, especially for clinical and pharmacological studies, which require reliable and well‐calibrated instruments to be interpretable and comparable. Preliminary investigations allowed preparation of standardized SM (normal NS and hyperaggregable HS), and checking of storage conditions (in accordance with the guidelines of the SSC of ISTH) of RBC in nutritive SAG mannitol for at least 2 or 3 weeks with subsequent washings and resuspension in SM. In our study, we compared erythro‐aggregometers of the same brand in 6 laboratories, using the same red blood cells (RBC) and suspending media (SM) for each…series of tests. EA was measured by laser backscattering with determination of aggregation time (AT), partial dissociation threshold (PDT) and aggregation index (AI). Prior to the study, devices were set up on the same day with the same standardized blood, and calibration data were then analyzed. Within‐assay precision (WAP) was assessed on 3 days for the 2 types of SM (n=18\times2 ). Between‐assay precision (BAP) was assessed on 6 occasions, once every month (n=6\times2\times 6 ). Accuracy was studied with 3 series of RBC resuspended in 10 SM of “unknown” aggregability. Good agreement was observed between 5/6 centers for the 3 parameters of EA. WEP was good: CV of AT ranging from 1.4 to 2.5% for the NS and from 1.4 to 2.4% for the HS. In each center, BAP was slightly lower than WEP (CV: 8–11.8% for the NS and 3.8–4.7% for the HS over the 6‐month study), with no drift, except for one center. Precision was always better with the HS than with the NS which seemed a better tool to assess it. As to accuracy, non‐significant differences were generally found between centers, with similar data to the reference values. This work also stressed the importance of the RBC parameter itself in rheological data. For the first time, a protocol for standardization of EA has been developed and evaluated, permitting the Quality Control of this technique.
Abstract: Discoid red blood cells (RBCs) deposited irreversibly on a horizontal glass surface are studied by means of optical microscopy and image analysis. The relative surface covered by the RBCs, as well as the variance of this surface coverage as a function of the cell concentration, are analyzed and compared to the results derived from the ballistic deposition (BD) model. This model describes the irreversible deposition of spherical particles under the influence of an infinitely large gravitation force and does not allow for overlaps between adsorbed particles. In spite of these characteristics, the BD model permits, surprisingly, to reproduce our experimental…observations on the deposition of RBCs on a flat surface. This finding is dicussed, in particular in respect to a former study where a model was developed for colloidal particles of this particular geometric shape.
Keywords: Erythrocytes, image processing, random deposition models