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Erythrocyte deformability studies by viscometry and filtrometry
Department of Medicine, University Hospital of Lund, Lund, Sweden.
1994 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

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.

Place, publisher, year, edition, pages
Lund, Sweden: Lunds Universitet , 1994. , 110 p.
Series
ISRN LUMEDW/MEMA--1042--SE
Keyword [en]
Erythrocyte deformability; viscometry; Filtrometry; Red cell membrane; Buffer; Filtration pressure; stress factors; Mean corpuscular volume; Sodium-potassium pump, Ouabain, Corticosteroids; Blood storage; Transfusion
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:lnu:diva-11785OAI: oai:DiVA.org:lnu-11785DiVA: diva2:418119
Public defence
1994-06-08, Föreläsningssal 3, Centralblocket, Universitetssjukhuset i Lund, Lund, 09:00 (Swedish)
Opponent
Supervisors
Note
Doktorsexamen i experimentell medicinAvailable from: 2011-06-07 Created: 2011-05-19 Last updated: 2011-06-07Bibliographically approved
List of papers
1. Studies on red cell filterability: Significance of buffer media
Open this publication in new window or tab >>Studies on red cell filterability: Significance of buffer media
1991 (English)In: Clinical Hemorheology, ISSN 0271-5198/91, Vol. 11, 317-324 p.Article in journal (Refereed) Published
Abstract [en]

Abstract

Blood cell deformability, most often measured as filterability through a polycarbonate filter, is a major determinant of the rheological properties of whole blood. In this study the influence of the suspension medium on the filterability of red cells was studied. We found a considerable variation in filterability between suspensions of red cells in media of different kinds. Thus the cells were suspended in phosphate buffered saline (PBS), pH 7.4, alone, in PBS with glucose 0.9 g/l, in PBS with bovine serum albumin (BSA) 2.5, 5.0 and 50 g/l, in PBS w i t h BSA 50 g/l,  fibrinogen 0.02 g/l and cholesterol 0.025 g/l, PBS with human plasma 19:1 (i.e. 1 ml plasma added to 19 ml of PBS) and in plasma alone. Photographs of cells in different suspension media were taken in the microscope. The filterability of red cells in PBS was greatly increased by addition of BSA and also the reproducibility was increased, specially at low concentrations of BSA. Red cells suspended in PBS alone, gave visually grossly distorted appearance but the addition of BSA or human plasma, normalized the morphology of the cells.

With human plasma, however, difficulties in reproducing the results were found. It is concluded that the choice of buffer medium is a critical point in blood cell filtration studies. The present study indicates that phosphate buffered saline with low concentration of bovine serum albumin might be a suitable choice.

Key words: Blood rheology; Blood viscosity; Blood cell filtration; Red cell deformability; Phosphate buffered saline; Buffer.

 

Place, publisher, year, edition, pages
New York, USA: Pergamon Press, 1991
Keyword
Blood rheology; Blood viscosity; Blood cell filtration; Red cell deformability; Phosphate buffered saline; Buffer.
National Category
Medical and Health Sciences
Research subject
Natural Science, Biomedical Sciences; Health and Caring Sciences, Caring Science
Identifiers
urn:nbn:se:lnu:diva-11656 (URN)
Available from: 2011-05-11 Created: 2011-05-11 Last updated: 2011-06-09Bibliographically approved
2. Erythrocyte deformability measured by filtrometry: Influences of variations in filtration pressure, MCV and MCHC
Open this publication in new window or tab >>Erythrocyte deformability measured by filtrometry: Influences of variations in filtration pressure, MCV and MCHC
1993 (English)In: Clinical Hemorheology, ISSN 0271-5198/93, Vol. 13, 791-801 p.Article in journal (Refereed) Published
Abstract [en]

Abstract

 Erythrocyte deformability can be measured as filterability through a polycarbonate filter. To evaluate the influence of variations in filtration pressures the present study was performed as filtration of red cell suspensions with a pore size of 5 μm at constant negative pressures of -10, -20, -30, -40 and -50 mm H2O in the St. George's Filtrometer. Filtration parameters were expressed as passage time, flow rate, flow resistance, initial relative filtration rate (IrFR), red cell transit time (RCTT) and clogging particles (CP). Passage time was decreased and flow rate was increased significantly at all filtration pressures compared to preceding pressure level (p<0.001). In the pressure range -10 to -30 mm H2O flow resistance decreased significantly (p<0.001), but was almost constant in the range -30 to -50 mm H2O. Also IrFR and RCTT showed a significantly greater change (p<0.001) when the pressure was increased from -10 to -20 mm H2O compared to the same pressure change in the range -30 to -50 mm H2O. CP varied more with pressure, but the greatest change was found in the range -10 to -20 mm H2O. Variations of MCV within the normal range were associated with changes in passage time, flow resistance and CP in the pressure range -20 to -50 mm H2O.

It is concluded that the filtration pressure is an important factor in studies on blood cell filterability. For the St. George's Filtrometer the optimal pressure range seems to be -30 to -50 mm H2O.

Key words:  Erythrocyte filterability; Filtration test; Stress factors; Filtration pressure; Wall shear stress;  Mean corpuscular volume; Mean corpuscular haemoglobin concentration.  

 

Place, publisher, year, edition, pages
New York, USA: Pergamon Press, 1993
Keyword
Erythrocyte filterability; Filtration test; Stress factors; Filtration pressure; Wall shear stress; Mean corpuscular volume; Mean corpuscular haemoglobin concentration.
National Category
Medical and Health Sciences
Research subject
Natural Science, Biomedical Sciences; Health and Caring Sciences, Caring Science
Identifiers
urn:nbn:se:lnu:diva-11709 (URN)
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-09-14Bibliographically approved
3. Changes in the functional state of the erythrocyte membrane: Significance for red cell filterability and blood viscosity
Open this publication in new window or tab >>Changes in the functional state of the erythrocyte membrane: Significance for red cell filterability and blood viscosity
1990 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, Vol. 50, 177-181 p.Article in journal (Refereed) Published
Abstract [en]

Abstract

Blood samples from nine healthy men were studied to determine the effect of ouabain and elevated serum calcium concentration on blood viscosity, measured by a rotational viscometer, and on red cell filterability by the St George's Filtrometer, giving values for clogging particles (CP) and red cell transit time (RCTT).  Blood viscosity at a standardized haematocrit of 45% and red cell filterability was investigated in blood samples incubated for 1 h with Ringer's solution only (control), with ouabain (0.70 mmol/l) in plasma, or with serum calcium concentration increased by 3.0 mmol/l by addition of CaCl2 Incubation with ouabain significantly reduced erythrocyte K+ concentration and increased that of Na+. Ouabain caused a decrease in blood viscosity (p<0.05-0.005) compared to controls, although there was no decrease in red cell filterability parameters. When incubating with calcium, CP and RCTT increased significantly indicating ”stiffer” red cells, but there was no increase in blood viscosity.

It is concluded that blood viscosity may be influenced by red cell factors not detected by CP or RCTT, which in turn appear to reflect red cell deformability with greater sensitivity and specificity than blood viscosity.  It is concluded also that the functional state of the cell membrane may be of significance for the rheological properties of erythrocytes. 

Key words: Blood cell deformability; Blood rheology; Calcium; Ouabain; Plasma viscosity; Red cell membrane; Sodium-potassium pump.

Keyword
Blood cell deformability; Blood rheology; Calcium; Ouabain; Plasma viscosity; Red cell membrane; Sodium-potassium pump.
National Category
Medical and Health Sciences
Research subject
Natural Science, Biomedical Sciences; Health and Caring Sciences, Caring Science
Identifiers
urn:nbn:se:lnu:diva-11650 (URN)
Available from: 2011-05-11 Created: 2011-05-11 Last updated: 2011-09-14Bibliographically approved
4. Effects of corticosteroids on erythrocyte filterability and blood viscosity in vitro
Open this publication in new window or tab >>Effects of corticosteroids on erythrocyte filterability and blood viscosity in vitro
1993 (English)In: Clinical Hemorheology, ISSN 0271-5198/93, Vol. 13, 237-243 p.Article in journal (Refereed) Published
Abstract [en]

Abstract

 The primary effects of steroid hormones are on gene expression, but steroids have also been reported to interact with cellular membranes and affect their properties. The aim of the present study was to elucidate the hemorheolqical effects of treatment with hydrocortisone. Blood samples from 10 healthy subjects were incubated with Ringer's solution (control) or Ringer´s solution + hydrocortisone (10 mg/L). Whole blood viscosity was studied in a rotational viscometer and erythrocyte filterability was measured in the St. George´s  Filtrometer. Addition of hydrocortisone resulted in a decreased whole blood viscosity (p<0.005), and a deteriorated erythrocyte filterability (p<0.005). An increased concentration of plasma triglycerides (p<0.02) and plasma total cholesterol (p<0.01) was also found upon addition of hydrocortisone. The concentration of sodium and potassium in plasma did not change. It is concluded that addition of hydrocortisone to concentrations occuring after commonly used therapeutic administration in man produces multiple hemorheological changes.

A reduced red cell deformability seems to be balanced by other rheological changes to produce a net reduction of blood viscosity.

Key words: Corticosteroids; Blood rheology; Blood viscosity; Erythrocyte filterability; Erythrocyte membrane.

Place, publisher, year, edition, pages
New York, USA: Pergamon Press, 1993
Keyword
Corticosteroids; Blood rheology; Blodd viscosity; Erythrocyte filterability; erythrocyte membrane
National Category
Medical and Health Sciences
Research subject
Natural Science, Biomedical Sciences; Health and Caring Sciences, Caring Science
Identifiers
urn:nbn:se:lnu:diva-11706 (URN)
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-09-14Bibliographically approved
5. A filtrometric study on red blood cells after storage in frozen form
Open this publication in new window or tab >>A filtrometric study on red blood cells after storage in frozen form
1994 (English)In: Clinical Hemorheology, ISSN 0271-5198/94, Vol. 14, no 6, 831-840 p.Article in journal (Refereed) Published
Abstract [en]

Abstract

 Background: For transfusion purpose, red blood cells can be frozen with glycerol for a long time. After thawing the red cells are washed, the intracellular glycerol is exchanged with water, and then the cells can be transfused. Most of the red blood cells that have been frozen have a potential for normal longterm survival after transfusion, but some of them become altered during the preservation procedure and are removed from the recipient's circulation, one possible mechanism for this being trapping of red cells in the spleen due to reduced deformability.

The aim of this study was to investigate the sensitivity of the St George's filtrometer to detect possible deformability defects in frozen, thawed and deglycerolized red blood cells.

Results: The suspension of deglycerolized cells showed a significant reduction in filterability indicating the presence of cells with reduced deformability. IrFR was decreased (p<0.05), RCTT increased (p<0.05) and CP increased (p<0.001) .

We found a reduction of filterability in these cells roughly corresponding to the presence of 0.01-0.1% glutaraldehyde treated cells. When 10% of the erythrocytes in a blood sample were hemolyzed and thus in ghost form IrFR and RCTT were unaffected, while CP was significantly increased (p<0.05) .

Conclusions: A suitable sampling technique may, however, minimize the influence from ghosts in blood samples used for filtrometry after freezing. Thus, in evaluating different freezing techniques filtrometry with the St George's instrument seems to have a high capacity to detect and quantify preservation injuries leading to decreased deformability in the red blood cells.

Key words: Blood storage; Erythrocyte deformability; Erythrocyte membrane; Glycerol; Hemorheology; Transfusion.

 

Place, publisher, year, edition, pages
New York, USA: Pergamon Press, 1994
Keyword
Blood storage; Erythrocyte deformability; Erythrocyte membrane; Glycerol; Hemorheology; Transfusion
National Category
Medical and Health Sciences
Research subject
Natural Science, Biomedical Sciences; Health and Caring Sciences, Caring Science
Identifiers
urn:nbn:se:lnu:diva-11707 (URN)
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-09-15Bibliographically approved

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