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Biomedical subjects

M Hornblower

Publications and source records attributed to M Hornblower.

15 recordsLinked to original sources
PubMed1991

Refrigerated storage of washed red cells.

Red cells washed and stored in a citrate-phosphate-glucose-adenine solution at pH 7.4-7.6 demonstrate excellent maintenance of adenosine triphosphate, elevation of 2,3-diphosphoglycerate well above normal levels for more than 6 weeks, reduced hemolysis and 24-hour in vivo survival comparable to that of cells stored in ADSOL. These results can be attributed in part to a chloride shift in which the washout of intracellular chloride is associated with an influx of OH-, which increases intracellular pH and thereby increases the rate of glycolysis. The phosphate functions primarily as a buffer to maintain both extra- and intracellular pH. Reducing the effective osmolality of the storage solution reduces hemolysis and improves cell morphology.

Adenosine Triphosphate↗
PubMed1991

Manipulating red cell intra- and extracellular pH by washing.

Washing red cells with solutions containing no anions capable of entering the cells is known to result in the loss of intracellular chloride and a counterflow of OH- which raises intracellular and lowers extracellular pH. Elevating the intracellular pH improves the quality of the cells during 4 degrees C storage. The extent to which intracellular pH can be raised and extracellular pH reduced depends not only on the inability of extracellular anions to enter the cells but also on the buffering capacity of the wash solution. Both intra- and extracellular pH can be manipulated by the judicious selection of anions or combinations of anions used in the wash solution.

Blood Preservation↗
PubMed1981

Freeze preservation of sickle erythrocytes.

The effect of short-term cryopreservation on metabolic, functional, and survival characteristics of erythrocytes from patients with sickle cell disease was examined. Post-thaw hemolysis of glycerolized sickle (SS) erythrocytes was greater (mean 12.9%) than in hemoglobin-AA cells (mean 4.7%). Freeze preservation had no apparent effect on red cell morphology, percent irreversibly sickled cells, and fetal hemoglobin content. There were modest reductions in ATP and 2,3-diphosphoglycerate in thawed, washed sickle erythrocytes (12.7% and 29.7%, respectively). However, the autologous survival of 51Cr-labelled SS red cells was not shortened by cryopreservation. The safety and efficacy of autotransfusion of cryopreserved red cells in alloimmunized sickle cell disease patients with anemic episodes unrelated to sickling need to be determined.

Adenosine Triphosphate↗
PubMedDate not supplied

Freezing and deglycerolizing sickle-trait red blood cells.

Sickle-trait red blood cells respond to freezing and thawing like normal cells, but during deglycerolization by centrifugal methods, they pack and hemolyze. This appears to be the result of changes in surface characteristics with suspension in hyperosmotic saline and even modest increases in osmolality result in packing with centrifugation. Modifications to permit deglycerolization of sickle-trait cells have been designed for use with both the Haemonetics and the IBM cell washing systems. Sickle-trait cells do not agglomerate satisfactorily but we were unable to devise a modification of this deglycerolizing system that would accommodate sickle-trait cells.

Anemia, Sickle Cell↗
PubMedDate not supplied

A simplified procedure for deglycerolizing red blood cells frozen in a high glycerol concentration.

Although the high (40 to 50 per cent) glycerol method of freezing red blood cells has many advantages, no feasible procedure for deglycerolizing with only a clinical centrifuge has been available. Thus this method has been restricted to blood centers that distribute a sufficient number of frozen cells to warrant the installation of automated cell washing equipment. However, by sedimenting the glycerolized cells prior to freezing and discarding the excess glycerol solution, postthaw deglycerolizing can be simplified to consist of an initial double dilution with hypertonic NaCl and isotonic saline-glucose followed by two cycles of sedimentation and resuspension in isotonic saline-glucose. The method is applicable to units frozen either at -80 C or in liquid nitrogen vapor. Units frozen in this way can also be deglycerolized in commercial automated cell washers using suitably modified protocols.

Blood Preservation↗
PubMedDate not supplied

Quality control for deglycerolized red blood cells.

A quality-control procedure to detect inadequately deglycerolized red blood cells is feasible, although the cost-effectiveness of routinely employing such a test needs to be considered by each individual blood bank. When the standard deglycerolizing protocol is meticulously followed by experienced personnel, the chances of an error that would result in inadequate deglycerolization are remote. The administration of cells with excess residual glycerol can result only in intravascular lysis of the infused cells. However, if a blood bank feels the need for a quality-control test for deglycerolized red blood cells, resuspending cells in 0.7% NaCl and estimating the per cent hemolysis using a color comparator is a simple and effective test.

Blood Preservation↗
PubMedDate not supplied

The preparation of red cells depleted of leukocytes. Review and evaluation.

The most commonly used methods for depleting red cells of leukocytes are the inverted spin procedure, which results in excessive red cell loss and poor leukocyte depletion, and washing, which is expensive and yields a product with a 24-hour shelf life. Clinical data now available suggest that nonhemolytic febrile transfusion reactions can be prevented in most clinical situations by microaggregate filtration of red cells during transfusion using the spin-cool-filter procedure with a screen filter. This procedure holds advantages for leukocyte removal, red cell recovery, cost, normal shelf-life, and simplicity over other washing and buffy coat removal procedures currently used. For highly alloimmunized patients requiring virtually total leukocyte removal and where alloimmunization is to be avoided at any cost, adhesion filtration or freezing and deglycerolization should be used.

Cell Separation↗