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PubMed2006

Whole blood viscosity and erythrocyte hematometric indices in chronic heroin addicts.

Whole blood viscosity (WBV) and hematometric indices of erythrocytes as red blood cell count (RBC), mean erythrocyte volume (MCV), hemoglobin (HGB), hematocrit (HCT), mean hemoglobin content of erythrocytes (MCH), HGB/HCT values (MCHC) and red blood cell distribution width (RDW) have been studied in a group of 15 chronic opioid addicts under methadone maintenance therapy with mean age 26.53 +/- 7.34 years. WBV elevation and changes in MCV, HGB, HCT, RDW were found in intravenous drug users compared to healthy individuals. As well, RBC was decreased leading to an increase in MCH and MCHC values. Correlation analysis suggested that the correlation among the RBC, HGB, HCT and WBV was the closest. Heroin macrocytosis (heroin macrocytic anemia) was established, related with the increased RDW in chronic heroin abusers. The results are in accordance with data revealing abnormal effects of alcohol and other drugs on whole blood rheology and hematometric/morphometric characteristics of erythrocytes.

Adult↗
PubMed1978

[Blood viscosity during long-term intravenous infusion of low-molecular dextran (author's transl)].

The effect on whole-blood viscosity and haematocrit was investigated in 54 persons during intravenous infusion of 500 ml Rheomacrodex 10% or 500 ml 0.9% sodium chloride solution for two, four and six hours. Rheomacrodex 10% led to a significant decrease in whole-blood viscosity after all infusion periods and up to two hours afterwards. The decrease in viscosity was definitely more marked at lower degrees of shear than at higher ones and with long-term infusion (four and six hours) than short-term infusion (two hours). Physiological saline caused significant decrease in viscosity compared with initial values at the end of four and six-hour infusions and only at shear of 230 s-1. During all infusion periods and for all degrees of shear the decrease in viscosity was significantly greater with Rheomacrodex 10% than physiological saline.

Blood Viscosity↗
PubMed2003

Cognitive performance, SPECT, and blood viscosity in elderly non-demented people using Ginkgo biloba.

The aging process is associated with several cognitive alterations. This study looks at the effects of taking dried extract of Ginkgo biloba, which has been used in several countries in an attempt to minimize these effects. The subjects were 48 men aged 60 - 70 matched between control and experimental groups for educational level. Evaluation was based on a number of neuropsychological tests in an attempt to cover the largest possible number of functions including Single Photon Emission Computer Tomography (SPECT) and measures of blood viscosity. The study was run on a double-blind basis with placebo and Ginkgo biloba groups evaluated over a period of 8 months. After treatment, the experimental group showed a reduction in blood viscosity, improved cerebral perfusion in specific areas and improved global cognitive functioning. The control group showed the opposite - higher blood viscosity, a reduction in cerebral perfusion (in specific areas), and cognitive deterioration in different functions. Although the mechanisms by which Ginkgo biloba may contribute to overall enhancement of the parameters evaluated have not been specified, this plant extract certainly appears to be effective in the treatment of cognitive deficits in older people. Further research into its use is called for on the basis of the results obtained here.

Aged↗
PubMed1997

[Clinical implications of high blood viscosity and its reduction bu photo-hemotherapy].

The paper is concerned with an essential blood characteristic--viscosity which is considered in relation of mechanisms responsible for its normal and abnormal characteristics, its role in the onset of circulatory disorders. High blood viscosity may contribute to development of vascular disturbances. Efficient methods of normalizing high blood viscosity are analyzed with special emphasis on photochemotherapy. Effects of ultraviolet, blue and red laser radiation on blood viscosity are outlined.

Blood Transfusion, Autologous↗
PubMed2003

Is whole body impedance a predictor of blood viscosity?

Bioelectrical impedancemetry (BIA) has received a widespread interest as a non-invasive approach to body fluid volumes. Since similar techniques have been studied to assess in vitro rheological properties of blood, we investigated the relationships between whole body impedance and blood viscosity parameters in order to determine possible predictive equations. 30 sportsmen (24.6+/-1.01 years; 73.96+/-1.62 kg; 177.73+/-1.33 cm) were enrolled into the study. Body composition was assessed with a multifrequency bioelectrical impedancemeter (Dietosystem Human IM Scan) using low intensity at the following frequencies: 1, 5, 10, 50 and 100 kHz. Viscometric measurements were done at 1000 s(-1) with a falling ball viscometer (MT 90 Medicatest). Hematocrit (Hct) was measured with microcentrifuge. A standardized exercise test was performed on a cycloergometer during 25 minutes. Physical working capacity (W170) was calculated and VO2max was evaluated with Astrand nomograms. Two hemorheological parameters were independently correlated with impedance (Z) measurements: whole blood viscosity (WBV) at 100 kHz (r=0.518; p=0.01) and Hct at 1 kHz (r=-0.485; p=0.01). Plasma viscosity was correlated multilinearly with water/fat free mass and Z at 10 kHz (r=0.441; p=0.02). In addition both WBV and Z at 100 kHz exhibited correlations with aerobic working capacity (VO2max ) with r=-0.482 and r=-0.475 (p</=0.05), respectively. A stepwise regression analysis selects Z at 100 kHz instead of WBV as a predictor of VO2max. These findings confirm our previous reports about relationships between whole body conductance for high frequency and aerobic working capacity and suggest a new approach for non-invasive evaluation of blood rheology with BIA.

Adult↗
PubMed2006

[Blood viscosity profile in rapidly progressive sensorineural hearing loss with positive Western-blot].

OBJECTIVE: To value a possible association between disorders in blood viscosity of patients with rapidly progressive sensorineural hearing loss (RPSHL) of autoimmune origin. PATIENTS AND METHODS: We studied the viscoelastic properties of blood in 43 subjects bearing of RPSHL and a positive Western-blot for anticochlear antibodies: whole blood viscosity (WBV) at different shear rates and erythrocyte filterability (EF). These results were related to hearing loss initially detected and recovery average one year later from steroid therapy. RESULTS: Just WBV at 230 sec(-1) shear rate was significatively higher in cases than in controls (p < 0.01). Hearing recovery degree correlated in an statistically way to increased values of EF (p < 0.01). There was no relation between initial hearing loss level and any rheology parameter. CONCLUSIONS: Autoimmune RPSHL does not show a pathophysiology mechanism associated to blood hyperviscosity. So, rheoactive therapies as plasmapheresis warrant no clinical improvement.

Adult↗
PubMed2004

Effects of a moderate-intensity aerobic program on blood viscosity, platelet aggregation and fibrinolytic balance in young and middle-aged sedentary subjects.

Regular physical activity is associated with reduced risk of cardiovascular disease although the mechanisms are unclear. Recent population-based studies suggest that the effect of physical activity may be at least partly a result of action on hemostasis. We tested the hypothesis that moderate-intensity aerobic training improves fibrinolytic activity and reduces platelet aggregation and blood viscosity. In 15 young (11 males and four females; age, 24-32 years) and 15 middle-aged (11 males and four females; age, 45-65 years) healthy, non-smoker, sedentary subjects, the maximum oxygen consumption, adenosine diphosphate-induced platelet aggregation, tissue plasminogen activator and plasminogen activator inhibitor type 1, antigen, hematocrit and blood viscosity were measured at baseline and after 12 weeks of aerobic exercise training (40 min three times a week at a training intensity adjusted to 60% of the individual heart rate reserve). After training, the maximum oxygen consumption was increased by 9% (P < 0.01) in the young group and by 7.3% (P < 0.05) in the middle-aged group. Adenosine diphosphate-platelet aggregation significantly decreased in the young (-30%; P < 0.05). The middle-aged group showed a 10.4% decrease in hematocrit (P < 0.05), and a 11.6 and 16.6% decrease in blood viscosity at 450/s and at 90/s rates of shear, respectively (P < 0.05), while the plasminogen activator inhibitor type 1 antigen plasma level increased 135% (P < 0.01). These data, some not consistent with others, only partially support the hypothesis that the beneficial effects of physical activity result from action on hemostatic balance. In particular, the changes in the fibrinolytic system in middle-aged subjects might suggest increased thrombotic risk. Thus a simple, straightforward conclusion is not possible at present, and further studies are required.

Adenosine Diphosphate↗
PubMed1980

Blood viscosity and the overnight fast.

A 12-hour overnight fast in 17 subjects did not result in a significant increase in blood viscosity, as occurs after a 24-hour fast. The usual preoperative fast does not therefore appear to have any adverse rheological effect. However, when it is necessary to prolong the fast, intravenous fluids should be given to prevent the expected increase in blood viscosity which then might have clinical effects as a result of decreased organ perfusion.

Adolescent↗
PubMed1979

Blood viscosity during fluid infusion in the preterm infant.

Whole blood viscosity, haematocrit and plasma osmolality were measured in a group of preterm infants receiving a standard infusion (60 ml/kg/d) of 10,7% dextrose water with 4% sodium bicarbonate. There were no significant changes in the three parameters during the infusion period. It was concluded that although the infused solution was hypertonic, it did not result in a hyperviscous or hyperosmolar state.

Acid-Base Equilibrium↗
PubMed1992

Blood viscosity and retinopathy of prematurity: a preliminary report.

Whole blood viscosity (WBV) and haematocrit (Hct) were measured in 8 very low birth weight premature neonates developing acute severe retinopathy of prematurity (ROP) and 7 control neonates without retinopathy or mild ROP. Single samples were collected at 32-34 weeks conceptual age. There was no statistically significant difference in WBV or Hct between the two groups. The results of this preliminary report suggest that WBV does not appear to play a major role in the development of advanced ROP, though larger studies are required to investigate this further.

Blood Viscosity↗
PubMed1988

Longitudinal changes in blood viscosity are correlated with fetal outcome.

The importance of longitudinal changes in maternal Whole Blood Viscosity (WBV) for fetal well-being was investigated. Consecutive WBV data were available, obtained from 44 pregnancies before 36 0/7 weeks. An increase in WBV was found to be associated with an unfavorable fetal outcome. This result might be considered as clinical evidence supporting the hypothesis that maternal WBV contains information on the efficacy of placental perfusion.

Adult↗
PubMed1990

Correlation of umbilical cord whole blood viscosity and the presence of fetal distress at birth: a mathematical modelling study.

This study was designed to investigate the relationship between umbilical cord blood viscosity and clinical parameters such as maternal parity, maternal smoking, mode of delivery, sex of infant and the incidence of fetal distress at birth using mathematical modelling. The results demonstrated vaginal delivery, male infants, infants of primigravidas and low cord whole blood viscosity at a high shear rate were covariables and were associated with an increased incidence of fetal distress and low Apgar scores.

Adult↗
PubMed2001

Modulation of red blood cell aggregation and blood viscosity by the covalent attachment of Pluronic copolymers.

Despite many years of research, the physiologic or possible pathologic significance of RBC aggregation remains to be clearly determined. As a new approach to address an old question, we have recently developed a technique to vary the aggregation tendency of RBCs in a predictable and reproducible fashion by the covalent attachment of nonionic polymers to the RBC membrane. A reactive derivative of each polymer of interest is prepared by substitution of the terminal hydroxyl group with a reactive moiety, dichlorotriazine (DT), which covalently bonds the polymer molecule to membrane proteins. Pluronics are block copolymers of particular interest as these copolymers can enhance or inhibit RBC aggregation. Pluronics exhibit a critical micellization temperature (CMT): a phase transition from predominantly single, fully hydrated copolymer chains to micelle-like structures. The CMT is a function of both copolymer molecular mass and concentration. This micellization property of Pluronics has been utilized to enhance or inhibit RBC aggregation and hence to vary low-shear blood viscosity. Pluronic-coated RBCs were prepared using reactive DT derivatives of a range of Pluronics (F68, F88, F98 and F108) and resuspended in autologous plasma at 40% hematocrit. Blood viscosity was measured at a range of shear rates (0.1-94.5 s(-1)) and at 25 and 37 degrees C using a Contraves LS-30 couette low shear viscometer. RBC aggregation and whole blood viscosity was modified in a predictable manner depending upon the CMT of the attached Pluronic and the measurement temperature: below the CMT, RBC aggregation was diminished; above the CMT it was enhanced. This technique provides a novel tool to probe some basic research questions. While certainly of value for in vitro mechanistic studies, perhaps the most interesting application may be for in vivo studies: typically, intravital experiments designed to examine the role of RBC aggregation in microvascular flow require perturbation of the suspending plasma to promote or reduce aggregation (e.g., by the addition of dextran). By binding specific Pluronics to the surface, we can produce RBCs that intrinsically have any desired degree of increased or decreased aggregation when suspended in normal plasma, thereby eliminating many potential artifacts for in vivo studies. The copolymer coating technique is simple and reproducible, and we believe it will prove to be a useful tool to help address some of the longstanding questions in the field of hemorheology.

Blood Viscosity↗
PubMed1998

Increased blood viscosity in iron-depleted elite athletes.

Since iron deficiency is associated with abnormal erythrocyte rheology, we investigated relationships between plasma ferritin and blood rheology in 36 male elite sportsmen (age: 22.38+/-0.9 years). On the whole, ferritin was negatively correlated with blood viscosity (r = -0.36, p < 0.05). When 23 subjects with low ferritin levels suggesting mild iron deficiency were compared with 13 matched sportsmen with normal ferritin levels, iron-deficient sportsmen were shown to have a higher blood viscosity at 1000 s(-l) (3.17+/-0.09 vs. 2.85+/-0.06 mPas, p < 0.05), explained by a higher plasma viscosity (1.38+/-0.02 vs. 1.31+/-0.02 mPa s, p < 0.05), while hematocrit and RBC rigidity index Tk were similar in the two groups. RBC aggregability index M (4.59+/-0.58 vs. 2.95+/-0.43 mPas, p < 0.05) and M1 (8.46+/-0.58 vs. 6.07+/-0.55, p < 0.01) were higher in iron-deficient subjects. Serum zinc was lower in iron-deficient sportsmen (0.73+/-0.02 vs. 0.83+/-0.02 mg/l, p < 0.01), but the score of early signs of overtraining was higher in this group (10.84+/-1.61 vs. 4.08+/-1.11, p < 0.01). These data suggest that mild iron deficiency as commonly seen in athletes, before anemia occurs, is associated with an increase in plasma viscosity and RBC aggregation, together with an increased subjective feeling of exercise overload.

Adult↗
PubMed1976

Increased whole blood viscosity on cooling in a patient with cold hemoagglutinin disease.

The whole blood and plasma viscosities have been evaluated in a patient with cold hemoagglutinin disease at different temperatures and at different shear rates. At 37 and 42 degrees C, whole blood viscosity values, regardless of the shear rate applied, resulted to be correspondent to the hematocrit value (31%). The values observed were similar to those noted in a patient with chronic bleeding anemia and an approximately equivalent hematocrit (33%). The same was true for plasma viscosity. At 32 degrees C, whole blood viscosity, regardless of the shear rate, resulted to be higher than expected. The values observed were similar to those noted in a normal subject with a clearly higher hematocrit value (44%) and definitely higher than those noted in the chronic anemia patient. On the contrary, plasma viscosity remained unchanged. These studies indicate that in cold hemoagglutinin disease, red cell aggregation and piling are capable of increasing blood viscosity.

Aged↗
PubMedDate not supplied

Fibrinogen, blood viscosity, and cerebral ischemia.

This study examines the effect of fibrinogen and consequent blood viscosity reduction on cerebral blood flow and cellular injury following severe cerebral ischemia for 30 minutes in 78 Wistar rats. In half of these rats 10 to 15 cc's of blood was removed and replaced with a mixture of 5% albumin and autologous red blood cells maintaining a constant hematocrit but resulting in a 30% decrease in fibrinogen and corresponding reduction in viscosity. Fibrinogen reduction in a slight increase in baseline CBF and the elimination of post-ischemic hyperemia at 24 hours. Both study and control animals showed a similar decrease in CBF at 30 minutes and 2 hours. There was no significant difference in the severity of ischemic cellular change between the fibrinogen reduction group and controls, although there was a significant inverse relationship between the amount of viscosity change and severity of cellular injury within the treatment group. Fibrinogen reduction alone cannot significantly ameliorate ischemic injury in this model. Viscosity reduction therapy should include reduction of hematocrit and alteration of red cell deformability.

Animals↗
PubMed2000

Blood viscosity and red cell morphology in subjects suffering from cirrhosis before and after treatment with S-adenosyl-L-methionine (SAM).

Alterations of fluidity of the hepatocytic membrane and of the transport related systems are the basis of the cholesteatic syndrome and favour the tissue accumulation of cytotoxic metabolites. S-Adenosyl-L-Methionine (SAM) is a natural molecule which acts as a giver of methylic groups and as an enzymatic activator in several enzymatic actions of transmethylase and of transulphuration and plays a key role in biochemical processes of hepatic cell. The aim of our study was to evaluate the effects of SAM on the restoration of the membrane fluidity and on the hepatic function in general. In studying the fluidity of the cell membrane we evaluated some hemorheological parameters (total blood viscosity and red cell morphology). Fluidity of the red cell membrane is one of the most important elements of red cell rheology. We studied 15 patients (Group A) suffering from micro- and macro-nodular cirrhosis verified through hepatic biopsy, with alcoholic or post-viral causes. We evaluated the values of: blood viscosity (with a cone-plate rheometer by Carri-med), haematocrit, plasma fibrinogen and the erythrocytic morphology at the optical microscope with the Zipursky-Forconi method before and after 7 days of therapy with SAM i.v.. Data were compared with those of a similar group (Group B) treated with traditional therapy only (hyposodic and hypoprotein diet supplemented with multivitamin preparations, vitamin K in particular, if necessary, and potassium sparing diuretics). We also measured biliary salts, alkaline phosphatase, transaminase and gamma-GT. In the first group we observed a statistically significant reduction of blood viscosity, haematocrit didn't change significantly; biliary salts reduced in a statistically significant way. Evaluation of red cell morphology showed in all cases a pathological percentage (>15%) of echinocytes and knizocytes which reduced to a mean of 5% after SAM therapy. We observed no further modifications of the other hemorheological parameters. Results demonstrate that SAM has a positive action on the fluidity of the membrane, as indicated by the improvement of haemorheological parameters and by the significant decrease of biliary salts, indicating the presence of cholesteasis.

Blood Viscosity↗
PubMed1988

Study of the factors affecting blood viscosity in patients with thromboangiitis obliterans. A preliminary report.

Hematocrit values, plasma fibrinogen levels, and erythrocyte deformability are well-recognized factors affecting blood viscosity. We studied the incidence of abnormalities in these factors among 17 patients suffering from thromboangiitis obliterans (Buerger's disease) compared with 14 normal age- and sex-matched control subjects. Hematocrit values and fibrinogen levels were higher, whereas the erythrocyte filterability index was lower among the patients with Buerger's disease (p less than 0.001). Incubation of washed erythrocytes from these patients with control plasma of blood type AB produced an improvement of the filterability index (p less than 0.005). Our findings suggest that patients suffering from Buerger's disease show, in addition to the well-recognized arterial lesions, an abnormality in the factors affecting blood viscosity. This may contribute to a worsening of the clinical manifestations. Evidence is presented suggesting that a plasmatic factor may be responsible for the impaired erythrocyte filterability.

Blood Viscosity↗