| 1. |
- Beshara, Soheir, et al.
(författare)
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Anemia associated with advanced prostatic adenocarcinoma : Effects of recombinant human erythropoietin
- 1997
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Ingår i: The Prostate. - 0270-4137 .- 1097-0045. ; 31:3, s. 153-160
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND METHODS: Nine patients with hormone-refractory metastatic prostatic adenocarcinoma and anemia were treated with recombinant human erythropoietin (rHuEpo) at a median dose of 150 U/kg BW 3 times a week subcutaneously. Baseline hemoglobin (Hb) ranged from 70 to 116 g/L, and the study duration was 12 weeks (median patient participation period was 8 weeks). RESULTS: Four patients demonstrated a median Hb increase of 20 g/L and were considered responders. Three patients showed a median increase of 17 g/L but required blood transfusion once, and were therefore considered as partial responders. Baseline erythropoietic status showed a significant correlation between serum Epo and Hb. Inadequate Epo production, evaluated by the observed/predicted log Epo ratio, was found in two patients. Defective bone marrow activity, demonstrated by low transferrin receptor (TfR), and hypoferremia in spite of abundant iron stores were also shown. Hemorheological investigations showed elevated plasma viscosity. CONCLUSIONS: Our results indicate that suppression of erythropoiesis can be mainly explained by the depressed marrow activity. The altered hemorheology might contribute to the anemia. This anemia could possibly be corrected with rHuEpo.
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| 2. |
- Fadul, Jamal E., et al.
(författare)
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Effects of LDL apheresis on blood rheology in two patients with homozygous familial hypercholesterolaemia
- 1997
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Ingår i: Blood Purification. - 0253-5068 .- 1421-9735. ; 15:3, s. 182-187
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Tidskriftsartikel (refereegranskat)abstract
- Changes in haemorheological and lipid variables were investigated in 2 patients with homozygous familial hypercholesterolaemia (FH) treated with low-density lipoprotein (LDL) apheresis using dextran sulphate adsorbent. The immediate effect of LDL apheresis was a fall in plasma fibrinogen by 50%, total and LDL cholesterol by 60%, plasma viscosity by 12% and whole blood viscosity by 17%. Before the 12th treatment session, plasma fibrinogen concentration remained reduced by 22%, whole blood viscosity by 17% and the plasma viscosity by 11% compared with the initial values. Total and LDL cholesterol in plasma also remained reduced by about 50%. We conclude that LDL apheresis, using dextran sulphate adsorbent, improves blood rheology. The decrease in plasma fibrinogen concentrations, plasma viscosity and LDL cholesterol might be factors contributing to the improved haemorheological properties.
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| 3. |
- Fadul, Jamal E. M., et al.
(författare)
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Effects of extracorporeal hemapheresis therapy on blood rheology
- 1997
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Ingår i: Journal of clinical apheresis. - 0733-2459 .- 1098-1101. ; 12:4, s. 183-186
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Tidskriftsartikel (refereegranskat)abstract
- The blood flow property is one of the factors determining blood perfusion and oxygen supply. The viscosity of the blood is primarily related to the hematocrit, but also to the amount of fibrinogen and other macromolecules present in the blood. Patients with ischemic heart disease have shown a rapid and safe improvement in their hemorheological state when treated with heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP). In this study we used two extracorporeal hemapheresis methods, plasmapheresis (PP) and immunoadsorption (IA), in 15 patients (eight patients treated with PP and seven patients with IA) with various diseases. Hemorheological variables and plasma fibrinogen were measured before and after the first and before the third treatment performed at 3 consecutive days. The aim of our study was to investigate the immediate effects of these two treatment modalities on the flow properties of blood. Immediately after the first PP and IA session statistically significant declines in plasma fibrinogen concentration, plasma viscosity, whole blood viscosity, and erythrocyte aggregation tendency were found. These changes persisted before the third treatment session. The erythrocyte fluidity and hematocrit remained unchanged. We conclude that extracorporeal hemapheresis therapy, with plasmapheresis or immunoadsorption, affects the blood rheology by decreasing the plasma viscosity and erythrocyte aggregation tendency. The decrease in plasma fibrinogen is probably the main factor underlying that, but other factors such as a decrease in immunoglobulins may also be of importance.
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| 4. |
- Furuland, Hans, et al.
(författare)
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Hemorheological and hemodynamic changes in predialysis patients after normalization of hemoglobin with epoetin-alpha
- 2005
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Ingår i: Scandinavian Journal of Urology and Nephrology. - : Informa UK Limited. - 0036-5599 .- 1651-2065. ; 39:5, s. 399-404
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Changes in blood viscosity and total peripheral resistance may contribute to increased blood pressure during partial correction of renal anemia with erythropoietin. An increase in hemoglobin level is followed by decreases in cardiac output and left ventricular mass. We examined how normalization of hemoglobin in predialysis patients affects both hemorheological and hemodynamic variables. MATERIAL AND METHODS: Twelve moderately anemic predialysis patients (hemoglobin 115.9+/-7.8 g/l) received epoetin-alpha with the aim of achieving a normal hemoglobin level (135-160 g/l). Hemorheological variables were measured using rotational viscometry. Cardiac index was determined by means of Doppler echocardiography. RESULTS: After 48 weeks, the hematocrit level had increased from 37.9%+/-3.0% to 47.0%+/-3.1% (p<0.0001). Blood viscosity increased from 3.84+/-0.33 to 4.59+/-0.4 mPa x s (p<0.001). Blood viscosity standardized to a hematocrit level of 45% and a plasma viscosity of 1.31 mPa x s did not change. Plasma viscosity, erythrocyte aggregation tendency and erythrocyte fluidity remained unchanged. The cardiac index decreased from 2.64+/-0.57 to 2.19+/-0.72 l/min/m(2) (p<0.05). The total peripheral resistance index increased from 3270+/-985 to 4013+/-1046 (dyn x s/cm(5))m(2) (p<0.05). Blood pressure remained constant, but the amount of antihypertensive medication used increased by 30%. CONCLUSIONS: Hemoglobin normalization in predialysis patients raised blood viscosity and total peripheral resistance due to an increase in hematocrit level, without other consistent hemorheological changes. Antihypertensive therapy had to be increased in many patients to maintain an acceptable blood pressure. The cardiac index was reduced, which may have prevented further development of left ventricular hypertrophy.
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| 5. |
- Linde, Torbjörn, et al.
(författare)
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Blood viscosity and peripheral vascular resistance in patients with untreated essential hypertension
- 1993
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Ingår i: Journal of Hypertension. - 0263-6352 .- 1473-5598. ; 11:7, s. 731-736
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The viscosity of blood is increased in patients with essential hypertension. The aim of the present study was to investigate the importance of the different variables of blood rheology to total peripheral resistance, and to elucidate whether inappropriate regulation of the formation of erythropoietin could be important. DESIGN: Nineteen consecutive patients with untreated essential hypertension were examined and compared with a group of matched healthy volunteers. METHODS: The haemorheologic variables were assessed by rotational viscometry and the haemodynamic variables by bioimpedance cardiography. The serum concentrations of erythropoietin were determined by radioimmunoassay. RESULTS: The whole blood viscosity and peripheral resistance index were elevated in the hypertensive group. The two variables were positively correlated with each other (r = 0.68, P = 0.0015). The plasma viscosity and erythrocyte aggregation tendency were increased and the erythrocyte deformability, measured as fluidity, was decreased in the hypertensive patients. In the male subpopulation (n = 12) the aggregation tendency was positively, and the deformability negatively, correlated with body mass index. The serum concentrations of erythropoietin were equal in the two groups. CONCLUSIONS: The increased total peripheral resistance in patients with essential hypertension may in part be explained by an increased blood viscosity, but the possibility of an opposite cause-effect relationship must also be taken into consideration. The haemorheological abnormalities observed in the present patients cannot be explained by high serum levels of erythropoietin.
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| 6. |
- Linde, Torbjörn, et al.
(författare)
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Decreased blood viscosity and serum levels of erythropoietin after anti-hypertensive treatment with amlodipine or metoprolol : results of a cross-over study
- 1996
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Ingår i: Journal of Human Hypertension. - 0950-9240 .- 1476-5527. ; 10:3, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- The increased viscosity of blood of hypertensive patients can be assumed to be a risk factor for the development of cardiovascular diseases. The aim of the present study was to elucidate whether anti-hypertensive treatment has any impact on blood theology. Twenty patients with previously untreated hypertension who consecutively attended our outpatient hypertension clinic were included in this prospective, open, cross-over study. The patients were randomly selected to treatment with amlodipine or metoprolol. The antihypertensive therapy was switched after 4 months. Haemorheological and haemodynamic variables were measured with rotational viscometry and impedance cardiography, respectively. Fifteen and 16 patients could be evaluated after amlodipine or metoprolol treatment respectively. The mean blood pressure (BP) decreased from 159 +/- 22/105 +/- 7 to 139 +/- 21/91 +/- 6 mm Hg on amlodipine and from 162 +/- 22/104 +/- 5 to 145 +/- 24/90 +/- 8 mm Hg on metoprolol therapy. After amlodipine treatment, the total peripheral resistance index decreased whereas metoprolol treatment was accompanied by a decrease in the cardiac index. Decreases in whole blood viscosity, haematocrit and serum erythropoietin were found after amlodipine as well as metoprolol treatment. After amlodipine the plasma viscosity decreased and the erythrocyte deformability increased in the majority of patients. Plasma fibrinogen decreased after metoprolol treatment. Despite the differences in haemodynamic mechanisms underlying the decrease in BP, amlodipine and metoprolol exert beneficial effects on blood viscosity. Haemodilution and a decrease in serum erythropoietin may be factors underlying this decrease in blood viscosity.
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| 7. |
- Linde, Torbjörn, et al.
(författare)
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The required dose of erythropoietin during renal anaemia treatment is related to the degree of impairment in erythrocyte deformability
- 1997
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Ingår i: Nephrology, Dialysis and Transplantation. - 0931-0509 .- 1460-2385. ; 12:11, s. 2375-2379
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Renal anaemia is rapidly corrected by recombinant human erythropoietin (rHuEpo) therapy, but the dose required varies greatly. Since impaired erythrocyte deformability may be one factor contributing to the development of renal anaemia, the interrelationship between that variable and the rHuEpo requirement was examined. METHODS: Twenty-five patients treated with hemodialysis and rHuEpo for at least 6 months were included in the study. The Hb value had been stable and the rHuEpo dose unchanged the last two months. Using a rotational viscometer, the fluidity of erythrocytes, separated from plasma and re-suspended in isotonic buffered saline to a standardized haematocrit, was taken as a measure of erythrocyte deformability. RESULTS: The average weekly dose of s.c. epoetin alpha was 186 +/- 93 U/kg body weight (range 56-370). The dose was correlated to the reticulocyte fraction (R = 0.69, P = 0.0001). When the rHuEpo dose was used as dependent variable and blood haemoglobin concentration, serum (S) albumin, S ferritin, S aluminium, S PTH, S urea, Kt/V/week, erythrocyte fluidity, and plasma viscosity were used as independent variables in a stepwise multiple regression analysis, only erythrocyte fluidity remained significantly negatively correlated to the rHuEpo dose (R = 0.5, P = 0.01). Despite a tendency towards higher doses of rHuEpo in patients with a C-reactive protein concentration exceeding 20 mg/l, the Hb was lower in these patients. CONCLUSIONS: We conclude that the interindividual differences in bone marrow response to rHuEpo were small in these patients. Impaired erythrocyte deformability and inflammation seem to be factors associated with increased rHuEpo requirement.
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| 8. |
- Metry, George, et al.
(författare)
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Effect of normalization of hematocrit on brain circulation and metabolism in hemodialysis patients
- 1999
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 10:4, s. 854-863
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Tidskriftsartikel (refereegranskat)abstract
- Full correction of anemia with recombinant human erythropoietin (rhEPO) has been reported to reduce the risk of cardiovascular morbidity and mortality and improve the quality of life in hemodialysis (HD) patients. Effects of normalization of hematocrit on cerebral blood flow and oxygen metabolism were investigated by positron emission tomography. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction ratio (rOER), and metabolic rate for oxygen (rCMRO2) were measured in seven HD patients before and after correction of anemia and compared with those in six healthy control subjects. In addition, blood rheology before and on rhEPO therapy was measured in HD patients, which included blood viscosity, plasma viscosity, erythrocyte fluidity, and erythrocyte aggregability. The results showed that plasma viscosity was high (1.51+/-0.19 mPa x s) and erythrocyte fluidity was low (85.8+/-4.8 Pa(-1) x s(-1)), while whole blood viscosity was within the normal range (3.72+/-0.38 mPa x s) before rhEPO therapy. After treatment, the hematocrit rose significantly from 29.3+/-3.3 to 42.4+/-2.2% (P<0.001), accompanied by a significant increase in the whole blood viscosity to 4.57+/-0.16 mPa x s, nonsignificant decrease in erythrocyte fluidity to 79.9+/-7.4 mPa(-1) x s(-1) and nonsignificant change in plasma viscosity (1.46+/-1.3 mPa x s). Positron emission tomography measurements revealed that by normalization of hematocrit, rCBF significantly decreased from 65+/-11 to 48+/-12 ml/min per 100 cm3 (P<0.05). However, arterial oxygen content (caO2) significantly increased from 5.7+/-0.7 to 8.0+/-0.4 mmol/L (P<0.0001), rOER of the hemispheres significantly increased from 44+/-3 to 51+/-6% (P<0.05) and became significantly higher than healthy control subjects (P<0.05). In addition, rCBV significantly increased from 3.5+/-0.5 to 4.6+/-0.6 ml/100 cc brain tissue. The results showed that oxygen supply to the brain tissue increased with normalization of hematocrit, but it was accompanied by increased oxygen extraction in the brain tissue. This may be assumed to be related to the decrease of erythrocyte velocity in the cerebral capillaries as a result of the decreased blood deformability and the increased plasma viscosity.
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| 9. |
- Baskurt, Oguz, et al.
(författare)
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New guidelines for hemorheological laboratory techniques
- 2009
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Ingår i: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 42:2, s. 75-97
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Tidskriftsartikel (refereegranskat)abstract
- This document, supported by both the International Society for Clinical Hemorheology and the European Society for Clinical Hemorheology and Microcirculation, proposes new guidelines for hemorheological methods used in experimental and clinical studies. It is based on a similar document entitled: "Guidelines for measurement of blood viscosity and erythrocyte deformability" published in 1986 by the Expert Panel on Blood Rheology of the International Committee for Standardization in Hematology. Recent methods techniques and instruments, as well as new approaches to interpretation of results, are added to these new guidelines; wide spread adoption should improve comparability between hemorheological laboratories and increase the reliability of rheological tests.
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| 10. |
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| 11. |
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| 12. |
- Lind, Lars, et al.
(författare)
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Shear stress in the common carotid artery is related to both intima-media thickness and echogenecity : the prospective investigation of the vasculature in Uppsala seniors study
- 2009
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Ingår i: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 43:4, s. 299-308
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Tidskriftsartikel (refereegranskat)abstract
- It has previously been shown that the degree of shear stress (SS) in the carotid artery is related to both plaque occurrence and intima-media thickness (IMT). Since the echogenecity also is an important feature of plaques, we investigated if a reduced shear stress also is related to the echolucency of plaque and the intima-media complex. In the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study, a population-based study of 1016 subjects aged 70, left common carotid artery diameter, IMT, the grey scale median (GSM) of the intima-media complex (IM-GSM) and the blood flow velocity were measured by ultrasound. Occurrence of plaque was noted, and the echogenecity of the plaques was visually estimated by the Gray-Weale classification. Shear stress was inversely related to both IMT and IM-GSM (p=0.0084 and p=0.003, respectively), independently of gender and coronary risk, estimated by the Framingham risk score. Shear stress was lower in subjects with carotid plaque (44% of the sample) than in those without (p=0.0013), and was inversely related to the echogenecity in the subjects with plaque (p=0.0092), independently of gender and coronary risk. A low shear stress in the common carotid artery was associated with both a thick IMT and an echolucent intima-media complex. A similar picture was seen when overt plaques were evaluated, suggesting that shear stress is of importance for both the extent and composition of atherosclerosis.
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| 13. |
- Linde, Torbjörn, et al.
(författare)
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Altered flow properties of blood and increased plasma fibrinogen in cyclosporin treated renal allograft recipients
- 1999
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Ingår i: Nephrology, Dialysis and Transplantation. - 0931-0509 .- 1460-2385. ; 14:6, s. 1525-1529
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Abnormalities in blood rheology may be factors contributing to cardiovascular complications and the progression of renal failure in kidney allograft recipients. The haemorheological variables haematocrit, fibrinogen, whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency and fluidity were measured in 27 cyclosporin A (CyA)-treated patients who had received a renal graft at least 6 months previously. Their creatinine clearance was in the range of 12-92 ml/min/1.73 m2 (mean 55+/-19). The values were compared with those obtained from a control group comprising 20 healthy subjects matched according to age, sex and smoking habits. RESULTS: The haematocrit, plasma fibrinogen, whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency, body mass index (BMI), mean arterial pressure (MAP) and serum triglycerides were increased in the transplanted patients, and the serum high density lipoprotein (HDL)-cholesterol and erythrocyte fluidity decreased. The haemorheological variables were used as dependent variables in a stepwise regression analysis with age, MAP, BMI, urinary albumin excretion rate, blood CyA concentration, creatinine clearance, and serum triglycerides, cholesterol and HDL-cholesterol as independent variables. Plasma fibrinogen was positively correlated with BMI and blood CyA. The whole blood viscosity was positively correlated with blood CyA and negatively with serum HDL-cholesterol. Only serum triglycerides remained correlated with erythrocyte aggregation tendency. CONCLUSIONS: All variables with a known impact on blood viscosity were altered in the present group of renal transplant recipients. Inappropriate regulation of erythrocyte formation, overweight, the use of CyA, high triglycerides and low HDL-cholesterol levels may be factors contributing to this. The importance of impaired flow properties of blood for the development of cardiovascular diseases and transplant glomerulosclerosis needs to be examined.
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| 14. |
- Linde, Torbjörn, et al.
(författare)
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Impaired erythrocyte fluidity during treatment of renal anaemia with erythropoietin
- 1992
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Ingår i: Journal of Internal Medicine. - 0954-6820 .- 1365-2796. ; 231:6, s. 601-606
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Tidskriftsartikel (refereegranskat)abstract
- Seventeen haemodialysis patients with renal anaemia were treated with recombinant human erythropoietin (rhEPO) and observed for 30 weeks. The viscosity of whole blood and plasma, the erythrocyte aggregation tendency, and the erythrocyte deformability, measured as fluidity, were analysed every second week. All patients responded with increasing haematocrit and whole-blood viscosity. The plasma viscosity and the erythrocyte aggregation tendency were already increased before the start of treatment, and remained unchanged during treatment. The basal erythrocyte fluidity tended to be impaired, although not significantly so. During treatment, significant impairment of fluidity was observed at the beginning of the treatment period. After 24 weeks the fluidity started to increase, and it later reached values observed before the start of treatment. Hence, the quality of the erythrocytes formed during the corrective phase of rhEPO treatment differs in some respects from that of cells formed at a normal production rate. The impaired fluidity might have important implications for the flow resistance in small vessels, and contribute to the development or aggravation of hypertension that is often seen during rhEPO treatment.
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| 15. |
- Linde, Torbjörn, et al.
(författare)
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Improved hemorheological properties during infusion of a lipid emulsion(Intralipid) in healthy subjects
- 2000
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Ingår i: Intensive Care Medicine. - 0342-4642 .- 1432-1238. ; 26:10, s. 1462-1465
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Lipid emulsions are commonly used for nutrition in critically ill patients. In these patients interventions resulting in deteriorated blood rheology and thereby an impaired microcirculation may be deleterious. This study examined the acute hemorrheological effects of the lipid emulsion Intralipid. We have recently shown that hyperinsulinemia exerts a negative effect on erythrocyte deformability, and here the effect of hyperinsulinemia combined with Intralipid was studied. SUBJECTS AND INTERVENTIONS: Eleven healthy subjects received Intralipid (200 mg/ml) intravenously as a bolus injection (0.5 ml/kg) over 10 min and thereafter as a continuous intravenous infusion (90 ml/h) for 4 h combined with heparin (200 U/h) to stimulate lipolysis. During the final 2 h an euglycemic hyperinsulinemic clamp was added. Five subjects underwent the same protocol with the exception that saline was given instead of Intralipid and heparin. MEASUREMENTS AND RESULTS: Whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency and fluidity were measured by rotational viscometry. Compared with basal and control values the Intralipid infusion caused greater erythrocyte fluidity (p < 0.05) and less aggregation tendency (p < 0.05). Whole blood and plasma viscosity remained unchanged. Hyperinsulinemia had no significant effect on the hemorrheological variables measured. CONCLUSIONS: Intralipid has no deleterious effects on blood rheology in healthy subjects. Instead, it leads to improved erythrocyte aggregation tendency and fluidity. If the emulsion exerts the same effects in patients with impaired circulation, the use of Intralipid may be beneficial in these patients.
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| 16. |
- Linde, Torbjörn, et al.
(författare)
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Reduced oxygen affinity contributes to improved oxygen releasing capacityduring erythropoietin treatment of renal anaemia
- 1993
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Ingår i: Nephrology, Dialysis and Transplantation. - 0931-0509 .- 1460-2385. ; 8:6, s. 524-529
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Tidskriftsartikel (refereegranskat)abstract
- In addition to haemoglobin concentration, haemoglobin oxygen affinity plays a major role in the oxygen releasing capacity of the blood. In this study we have measured oxygen affinity as P50 and calculated the oxygen releasing capacity of blood from 10 haemodialysis patients treated with erythropoietin (rHuEpo). The patients were examined with different assays before start of treatment, after 11 weeks, and after 27 weeks. During the first phase of treatment the oxygen releasing capacity improved because of an increase in the haemoglobin concentration and P50. During the second phase there was a further significant increase in haemoglobin concentration, but due to a decrease in the P50 value the oxygen releasing capacity remained unchanged. Despite an unchanged oxygen releasing capacity and total blood volume, the antihypertensive treatment had to be increased during that phase of treatment. An increase in whole-blood viscosity may explain the increased need of antihypertensive drugs. The increase in P50 during the first phase of rHuEpo treatment can probably be explained by decreased mean age of the erythrocyte population and implies that the beneficial effect is greater than could be concluded from the increase in haemoglobin concentration.
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| 17. |
- Norberg, Åke, et al.
(författare)
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Do ethanol and deuterium oxide distribute into the same water space in healthy volunteers?
- 2001
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Ingår i: Alcoholism. - 0145-6008 .- 1530-0277. ; 25:10, s. 1423-1430
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Tidskriftsartikel (refereegranskat)abstract
- Background: The volume of distribution at steady state for ethanol (VSS) is thought to be identical to the total body water (TBW). We compared a two-compartment pharmacokinetic model with parallel Michaelis-Menten and first-order renal elimination with the classical one-compartment zero-order elimination model. Ethanol concentration-time profiles were established for breath, venous blood, and urine. The values of VSS obtained for ethanol were compared with TBW determined by deuterium oxide dilution. Methods: Sixteen healthy volunteers each received a 30-min intravenous infusion of ethanol on two occasions. Ethanol was measured in breath by a quantitative infrared analyzer and in blood and urine by headspace gas chromatography. Deuterium oxide was given as an intravenous injection and measured in serum by isotope-ratio mass spectrometry. Components of variation were calculated by ANOVA to determine the precision of the estimates of VSS and TBW. Results: Mean TBW, determined by deuterium oxide dilution, was 44.1 ▒ 3.9 liters (▒SD) for men, corresponding to 0.61 liters/kg, and 37.4 ▒ 3.2 liters for women, or 0.54 liters/kg. Estimates of VSS from blood-ethanol pharmacokinetics were 87.6% of TBW according to isotope dilution and 84.4% for breath analysis with the two-compartment model. This compares with 95.1% and 95.4% for blood and breath alcohol, respectively, when the classical zero-order kinetic analysis is used. The precision of the estimates of VSS and TBW was between ▒1.56 and ▒2.19 liters (95% confidence interval). Conclusions: Ethanol does not distribute uniformly into the TBW. The precision of measuring VSS by ethanol dilution was comparable to estimates of TBW by isotope dilution. Results of noninvasive breath ethanol analysis compared well with use of venous blood for estimating VSS. The sophisticated two-compartment model was much superior to the classical one-compartment model in explaining the total concentration-time course of intravenously given ethanol.
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| 18. |
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| 19. |
- Persson, Sylvi
(författare)
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Erythrocyte deformability studies by viscometry and filtrometry
- 1994
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- DOCTORAL DISSERTATION Abstract The present thesis concerns factors of major importance in filtrometric studies of human erythrocytes, e.g. influence of buffer media, importance of filtration pressure for filtration through micropores and possible effects of damaged and hemolyzed blood cells. The reproducibility of results from haemorheological studies has also been studied. Furthermore the rheological effects on erythrocytes from experimental, functional manipulation have been studied, e.g. by adding of digitalis glycosides and corticosteroids. Finally, the rheological properties of blood, that has been stored in frozen form, have been evaluated. The first paperof this thesis shows that red cell morphology, flow behaviour and also the reproducibility of measurements are strongly dependent on the composition of the surrounding buffer medium. Paper 2points out the importance of a carefully chosen filtration pressure to make the experimental settings to come as close to the in vivo capillary circulatory conditions as possible. Influence from variations in MCV is also demonstrated in this paper. In paper 3the function of the sodium/potassium pump has, by adding of ouabain, been interfered with, thus creating changes of the intracellular ion and charge conditions. This, in turn, influences on blood viscosity. When incubating erythrocytes with calcium ions a more direct effect on erythrocyte deformability is seen. In paper 4is described the complex effect of corticosteroids on flow properties of red blood cells. Thus it is shown that the over all effect of adding a corticosteroid to a suspension of blood cells seems to be a decreased viscosity, in spite of the fact that a reduced deformability of red blood cells can be seen as a parallel phenomenon. Finally, paper 5indicates that the damage caused on red blood cells during preservation by glycerol and in frozen form may be of a haemorheological kind. Filtration through micropores seem: to be an adequate method for evaluation of damage caused to cells by freezing and parallels to the in vivo conditions in the spleen can be seen. The St George's Filtrometer, which was used in this study, seems to be able to find damaged cells in as low concentrations as 1/1000. It is concluded that a buffer solution, with a small amount of albumin added should be used in studies on filterability of red blood cells. It is also concluded that the cells are sensible to the pressure conditions used in the filtration process. A negative pressure around 30 mm H20 seems to be suitable in this type of filtration studies. Haemorheological effects of digitalis glycosides and corticosteroids are elucidated and so is the effect of blood preservation through glycerol treatment and freezing on red blood cells.
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| 20. |
- Purins, Karlis, et al.
(författare)
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Brain tissue oxygen monitoring : a study of in vitro accuracy and stability of Neurovent-PTO and Licox sensors
- 2010
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 152:4, s. 681-688
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Tidskriftsartikel (refereegranskat)abstract
- OBJECT: Periods of brain tissue ischemia are common after severe head injury, and their occurrence and duration are negatively correlated with outcome. Accurate and reliable measurement of brain tissue oxygenation (B(ti) pO(2)) may be a key to improve patient outcome after severe head injury. Knowledge of stability and accuracy of the B(ti) pO(2) systems is crucial. We have therefore conducted a bench test study of new Neurovent-PTO(R) (NV) and Licox(R) (LX) oxygen tension catheters to evaluate the sensor accuracy, response time to different oxygen tensions, response to temperature changes and long-term stability. METHODS: For all experiments five new fluorescent NV sensors and five new electrochemical LX sensors were used. The catheter probes were placed into a container filled with a buffer solution. The solution was equilibrated with five high precision calibration gases. The accuracy of the probes was recorded after an equilibration period of 20 min in O(2) concentrations of 5, 10, 20, 30 and 40 mmHg at 37.0 +/- 0.2 degrees C. The probe response to an increase in temperature from 37.0 degrees C to 38.5 degrees C to 40.0 degrees C in two different gases with O(2) concentrations of 10 and 20 mmHg were analysed. We also recorded the time for reaching 90% of a new oxygen concentration level when switching from one concentration to another. Finally, to test if there was a time-dependant drift in pO(2) recordings, all sensors were left in 10 mmHg O(2) solution for 10 days, and recordings were taken every 24 h. RESULTS: In all gas concentrations, NV and LX sensors measured pO(2) with high accuracy and stability in vitro (mean differences from calculated values were for NV 0.76-1.6 mmHg and for LX -0.46-0.26 mmHg). Both sensors showed a shorter response time to pO(2) increase (for NV 56 +/- 22 s and for LX 78 +/- 21 s) compared to pO(2) decrease (for NV 131 +/- 42 s and for LX 215 +/- 63 s). NV pO(2) values were more stable for changes in temperature, while LX sensors showed larger standard deviations with increasing temperature (the difference from the calculated values in 19.7 mmHg O(2) at 40 degrees C were for NV probes between 0.5 and 1.7 mmHg and LX between -2.3 and 1.9 mmHg). Both sensors gave stable results with low standard deviations during long-term (10 days) use, but with a slight elevation of measured pO(2) levels by time. CONCLUSIONS: Both NV and LX were accurate in detecting different oxygen tensions, and they did not deviate over longer recording times. However, LX needed a significantly longer time to detect changes in pO(2) levels compared to NV. Furthermore, LX probes showed an increased standard deviation with higher temperatures.
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| 23. |
- Sandhagen, Bo
(författare)
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Reologi
- 2006
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Ingår i: Svenskt Njurmedicinskt vårmöte.
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Konferensbidrag (populärvet., debatt m.m.)
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| 24. |
- Sandhagen, Bo, et al.
(författare)
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Whole blood viscosity and erythrocyte deformability are related to endothelium-dependent vasodilation and coronary risk in the elderly : The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study
- 2012
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Ingår i: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 50:4, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- It has previously been shown that a high hemoglobin value, a major determinant of whole blood viscosity (WBV), predicts cardiovascular events. One putative mechanism might be an impaired endothelial function. Erythrocyte deformability is another rheologic feature of the erythrocyte being of importance for the flow properties of the blood, especially in the capillaries. The present study evaluates the relationships between blood viscosity, erythrocyte deformability assessed as erythrocyte fluidity (EF), coronary risk and endothelial vasodilatory function. In the population-based PIVUS study (1016 subjects aged 70); endothelium-dependent vasodilation (EDV) was evaluated by the invasive forearm technique with acetylcholine given in the brachial artery and the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD). WBV, plasma viscosity (PV) and EF were measured in a random sample of 573 subjects. WBV and PV were positively and EF negatively related to Framingham risk score. EDV was inversely related to both whole blood and plasma viscosity. FMD was not related to any rheologic variable. In multiple regression analyses WBV and EF were significantly related to EDV independently of gender, hypertension, smoking, hypercholesterolemia, obesity and diabetes. Acetylcholine-induced vasodilation in the forearm, but not FMD, was negatively related to whole blood viscosity and positively related to EF independently of traditional risk factors in elderly subjects, indicating a pathophysiological link between impaired hemorheology and coronary risk.
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| 25. |
- Sandhagen, Bo
(författare)
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Whole blood viscosity and erythrocyte fluidity are related to endothelium-dependent vasodilation and coronary risk in the elderly
- 2007
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Ingår i: 14th Conference of the European Society for Clinical Hemorheology and Microcirculation. Dresden, 27-30 juni, 2007..
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Konferensbidrag (populärvet., debatt m.m.)abstract
- Background: It has been shown that an elevated blood viscosity predicts cardiovascular events. One putative mechanism might be an impaired endothelial function. Further, erythrocyte fluidity, representing erythrocyte deformability, is a characteristic rheologic feature of importance for the flow properties of the blood, especially in the smallest vessels.The present study evaluates the relationships between erythrocyte fluidity, whole blood and plasma viscosity, coronary risk and endothelial vasodilatory function.Methods and results: In a population-based study on 1016 subjects aged 70, endothelium-dependent vasodilatation (EDV) was evaluated by a) the invasive forearm technique with acetylcholine given in the brachial artery, b) the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD) and c) pulse wave analysis with beta-2-agonist (terbutaline) provocation. Erythrocyte fluidity, and whole blood and plasma viscosity were measured in a random sample of 573 subjects.Whole blood and plasma viscosity were related to Framingham risk score (r=0.20, p< 0.0001). EDV was inversely related to both whole blood and plasma viscosity (r= -0.16, p=0.0004 and r= -0.14, p=0.0015, respectively). So was also the pulse wave response (r= -0.20, p<0.0001 and r= -0.09, p=0.045, respectively), but not FMD (r= 0.01-0.02).Erythrocyte fluidity was inversely related to the Framingham risk score (r= - 0.12, p=0.0009), EDV (r= 0.12, p=0.0064) and to the pulse wave response (r= -0.17, p=0.0002), but not to FMD (r= -0.01).Multiple regression analysis showed whole blood viscosity and erythrocyte fluidity to be significantly related to EDV and the pulse wave response independently of haematocrit, gender, hypertension, smoking, hypercholesterolemia, obesity and diabetes.Conclusion: Whole blood and plasma viscosity as well as erythrocyte fluidity were related to coronary risk. Acetylcholine-induced vasodilatation in the forearm and terbutaline-induced changes in pulse wave reflection were both inversely related to whole blood viscosity and erythrocyte fluidity independently of traditional risk factors in elderly subjects, indicating a pathophysiological link between impaired haemorheology and coronary risk.
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| 26. |
- Xu, H., et al.
(författare)
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Lipophilic index, kidney function, and kidney function decline
- 2016
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Ingår i: NMCD. Nutrition Metabolism and Cardiovascular Diseases. - : Elsevier BV. - 0939-4753 .- 1590-3729. ; 31, s. 177-177
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Unhealthy dietary fats are associated with faster kidney function decline. The cell membrane composition of phospholipid fatty acids (FAs) is a determinant of membrane fluidity and rheological properties. These properties, which have been linked to kidney damage, are thought to be reflected by the lipophilic index (LI). We prospectively investigated the associations of LI with kidney function and its decline. Methods and results: Observational study from the Prospective Investigation of Vasculature in Uppsala Seniors including 975 men and women with plasma phospholipid FAs composition and cystatin-C estimate glomerular filtration rate (eGFR). Of these, 780 attended reexamination after 5 years, and eGFR changes were assessed. Participants with a 5-year eGFR reduction >= 30% were considered chronic kidney disease (CKD) progressors (n = 198). LI was calculated as the sum of the products of the FA proportions with the respective FAs melting points. Blood rheology/viscosity measurements were performed in a random subsample of 559 subjects at baseline. Increased LI showed a statistically significant but overall weak association with blood, plasma viscosity (both Spearman rho = 0.16, p < 0.01), and erythrocyte deformability (rho = -0.09, p < 0.05). In cross-sectional analyses, LI associated with lower eGFR (regression coefficient 3.00 ml/min/1.73 m(2) 1-standard deviation (SD) increment in LI, 95% CI: -4.31, -1.69, p < 0.001). In longitudinal analyses, LI associated with a faster eGFR decline (-2.13 [95% CI -3.58, -0.69] ml/min/1.73 m(2), p < 0.01) and with 32% increased odds of CKD progression (adjusted OR 1.32 [95%, CI 1.05-1.65]). Conclusions: A high LI was associated with lower kidney function, kidney function decline, and CKD progression.
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