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Biomedical subjects

K Hedlund

Publications and source records attributed to K Hedlund.

17 recordsLinked to original sources
PubMed1988

The bottom and top system: a new technique for blood component preparation and storage.

A new, automated technique for the preparation of blood components is described. A system of 3 or 4 integrally connected plastic containers (Optipac) is handled by a new type of extractor (Optipress). The container in which the blood is collected has an outlet at the top and another at the bottom. After normal centrifugation to obtain separation of the blood components, these are squeezed out from the top and bottom simultaneously under control of a photocell. The primary separation step results in three components: a leukocyte-poor red-cell suspension in SAGM medium, CPD plasma, and a buffy-coat preparation. The system has been tested in two laboratories (lab A and lab B). A 'heavy-spin' centrifugation to obtain a maximum yield of cell-poor plasma gave the best removal of leukocytes from the red cells; the remaining leukocyte content was 0.46 +/- 0.25 (lab A) and 0.5 +/- 0.4 (lab B) x 10(9)/red-cell unit. Platelet concentrates can be prepared either the normal way via platelet-rich plasma or from buffy coat. Red-cell 24-hour autologous posttransfusion survival using labeling with 51Cr was 87.5 +/- 4.1% (lab A) after 35 days, and 84.2 +/- 4.2% (lab A) and 77.5 +/- 1.5% (lab B) after 42 days. Red-cell morphology and fluidity compared favorably to previous studies using the same additive solution in traditional plastic-bag systems. The total adenine nucleotide concentration was maintained normal for 42 days.(ABSTRACT TRUNCATED AT 250 WORDS)

2,3-Diphosphoglycerate↗
PubMed1986

Effects of oxygen on red cells during liquid storage at +4 degrees C.

Red cells collected in CPD and suspended in SAGM medium were stored in plastic (PVC) containers for 42 days at +4 degrees C. Comparison was made between aerobic storage (normal air exposure) and anaerobic storage (exposure to nitrogen gas). The air-exposed units showed a strong increase in pO2 and oxygen saturation as a result of oxygen penetration into the bags from outside. This resulted in a decrease in ATP and adenylate energy charge, a slower metabolization of adenine and hypoxanthine to AMP and IMP, respectively, and a faster decrease in red cell fluidity. To explain the findings it is concluded that aerobic storage causes an increased need of high-energy phosphate groups, possibly used for replacement of the phospholipid membrane bilayer or in repair of phosphate bonds in the cytoskeleton. It is further proposed that a slight formation of hydrogen peroxide from free oxygen radicals moderately increases the oxidation of reduced (GSH) to oxidized (GSSG) glutathione and slightly enhances the need for reduced nicotinamide-adenine dinucleotides mainly provided by increased flux through the pentose phosphate shunt.

Adenosine Triphosphate↗
PubMed1985

Studies on the mechanism of human red cell loss of viability during storage at +4 degrees C in vitro. I. Cell shape and total adenylate concentration as determinant factors for posttransfusion survival.

Red cells stored in SAGM medium for 42 days at +4 degrees C were rejuvenated by bicarbonate, pyruvate and adenosine. Autologous 24-hour posttransfusion survival was determined in untreated as well as rejuvenated cells and showed an improvement from 77.4 +/- 4.7 to 89.2 +/- 7.2%. The erythrocyte adenylate energy charge decreased relatively more than the total adenylate concentration during storage, but the latter correlated better with posttransfusion red cell survival. Considerable deteriorations in red cell morphology (expressed as morphology index) and in deformability (measured as red cell fluidity) were observed during storage but were partly reversed by rejuvenation. The morphology index and the posttransfusion survival showed a significant correlation (r = 0.95, p less than 0.005) after, but not before, rejuvenation, indicating that the remaining changes are more permanent and decisive of survival. It is suggested that, in the proportion of stored erythrocytes which respond to rejuvenation, the capacity and time dependence of recovery of normal shape and flexibility are important.

Adenine↗
PubMed1985

Storage of red cells in a CPD/SAGM system using Teruflex PVC.

A quadruple plastic bag system made of Teruflex PVC (Terumo) was tested. Red cells separated from plasma and buffy coat were resuspended in SAGM solution. After storage for 42 days, the 24-hour posttransfusion autologous survival was 73.3 +/- 6.6% (means +/- SD), range 61.8-80.7%, n = 10. The shape of the cells was changed so that normal or slightly abnormal morphology was found in 37 +/- 7% of the cells after 42 days. Spontaneous in vitro hemolysis was 0.63 +/- 0.32% (range 0.28-1.13). A sufficient glucose reserve still remained at the end of storage, but glucose consumption and lactate production were impaired during the last 2 weeks due to the increasing acidity. By extrapolation from other studies it is suggested that 35 days is a more suitable shelf life than 42 days in this system.

Adenosine Triphosphate↗
PubMed1983

Red cell suspensions in SAGM medium. Further experience of in vivo survival of red cells, clinical usefulness and plasma-saving effects.

Red cells depleted of buffy coat and more than 90% of the plasma were suspended and stored in a medium composed of sodium chloride, adenine, glucose and mannitol (SAGM). The 24-hour posttransfusion survival of 51Cr-labeled red cells was 83.5 +/- 5.3% (n = 4) after storage for 35 days and 77.4 +/- 4.7% (n = 6) after 42 days. No abnormal in vivo hemolysis occurred as judged from posttransfusion haptoglobin consumption studies. No abnormal body temperature elevation was found at continuous pertransfusion recordings. The frequency of febrile or urticarial transfusion reactions was 0.19% as compared to 0.68% during a whole-blood transfusion period. Since a mean of 280 ml of plasma can be collected from each blood unit the plasma-saving effects of the system are considerable. Favorable large-scale clinical experience is reported.

Adenine↗
PubMed1983

Assessing a quality control program for erythrocyte preservation and attempts to improve quality of cells after storage at +4 degree C.

About 22 in vitro parameter values were used to evaluate the condition of erythrocytes stored at +4 degrees C in SAGM (1) medium for 28 and 42 d. The parameters were related to such different functions of the erythrocyte, as glycolysis, ion transport, purine metabolism, membrane function and membrane morphology immediately after storage and after subsequent incubation at physiological conditions for 30 min. The evaluation included comparison with posttransfusion viability after 42 d of storage. The investigation gives information in statistical terms about relations between the parameter values and their change with storage time. Total adenylates are superior to ATP in predicting post transfusion viability. There is a good correlation between the in vitro parameters: total adenylates, morphology score and erythrocyte fluidity.

Adenine Nucleotides↗
PubMed1983

Cell shape and total adenylate concentration as important factors for posttransfusion survival of erythrocytes.

Red cells were stored for 42 days in a CPD/SAGM plastic bag system and then rejuvenated with bicarbonate, pyruvate and slow addition of adenosine. The reversibility and the time dependence of metabolic and morphologic changes were compared with autologous, posttransfusion survival. Total adenylates correlated better (r = 0.88) than ATP with viability in vivo ATP was better maintained when the blood was stored under anaerobic than aerobic conditions. A high correlation between morphology and viability was found in rejuvenated cells (r = 0.95). It is suggested that the time needed for reversal of changes is essential for viability.

Adenine Nucleotides↗
PubMed1980

Red blood cell preservation in protein-poor media. 2. Studies of changes in red cell shape during storage.

Red cells stored for up to 35 days have been studied by scanning electron microscopy. Formation of spicules occurred under all storage conditions in CPD and CPD-adenine whole blood, CPD-adenine red cell concentrate, and saline-adenine-glucose red cell concentrate. The number of cells with normal or near normal shape was larger if the blood was stored as a moderately concentrated suspension in saline-adenine-glucose medium or in autologous plasma as compared to the storage as whole blood. The occurrence of echinocytes during storage at +4 degrees C was not correlated to red cell ATP. It was shown that a drastic reduction of ATP leads to an increased formation of both spherocytes and echinocytes. The change of red cell shape during storage at +4 degrees C thus can be due to two processes, one unrelated to ATP and another related to ATP. Why storage as red cell concentrate is superior is not fully understood.

Blood Specimen Collection↗
PubMed1978

Clinical usefulness of red cells preserved in protein-poor mediums.

Blood is normally collected into a combined anticoagulating and preserving medium. We performed a study to ascertain whether improvements could be made by separation of these two functions. Addition of saline-adenine-glucose solutions (40 to 100 ml per blood unit) to buffy-coat-poor red-cell concentrates allowed storage for as long as 35 days with 24-hour erythrocyte post-transfusion survival of 83 +/- 6.8 per cent (+/0 S.D.). Potassium leakage was lower, and in vitro hemolysis somewhat higher than that of whole blood. The microaggregate content after 21 days was 16 per cent of that in whole blood. In over-pressure transfusions the flow rate of red cells was the same with red-cell concentrates to which 80 to 100 ml of suspension medium had been added (hematocrit less than or equal to 60 per cent) as with whole blood. Removal of the buffy coat was essential to reduce hemolysis. We conclude that red cells can be successfully stored in a simple protein-poor medium.

Adenine↗
PubMed1975

Simple procedure for the removal of nonspecific inhibitors of rubella virus hemagglutination.

The adsorption of serum lipoproteins onto an insoluble matrix of colloidal silicic acid results in the removal of nonspecific inhibitors of rubella virus hemagglutinin. The procedure can be performed in 15 min at room temperature. Comparative studies using both the dextran sulfate-CaCl2 and heparin-MnCl2 methods for removal of inhibitors demonstrated that the colloidal silicic acid procedure yielded identical hemagglutination inhibition titers. In addition, it is technically feasible to read titers below 1:8.

Adsorption↗
PubMedDate not supplied

Red cell preservation in protein-poor media. III. Protection against in vitro hemolysis.

Red cells stored under blood bank conditions normally show less than 1% spontaneous in vitro hemolysis even after 5 weeks; larger hemolysis may be found if the cells are suspended and stored in a saline-adenine-glucose (SAG) solution with very little trapped plasma. Delay of the addition of the suspension medium, return of 25 ml plasma after a maximal plasma harvest, addition of mannitol 10-30 mmol.1(-1) to the suspension medium were alternative and effective ways of keeping the spontaneous lysis within normal limits. Mechanical traumatization (centrifugation or shaking) caused considerably more damage to the red cells when these were highly concentrated than when they were diluted. A cell suspension in SAG is a more suitable product for hemotherapy than strongly packed red cell concentrates.

Adenine↗