Biomedical subjects

A M Suontaka

Publications and source records attributed to A M Suontaka.

3 recordsLinked to original sources

PubMed1992

Proteolytic activity during storage of platelets in plasma.

Proteolytic activity was studied in platelet concentrates (PC) stored in plasma at 22 degrees C. In experiment 1, two PC with a higher (A) and a lower (B) white cell concentration were prepared from each of nine donors by centrifugation. Aliquots of the cell-free plasma, PPP, were stored as a control. Samples for the assay of fibrinopeptide A (FPA), elastase, spontaneous proteolytic activity (SPA), kallikrein-inhibiting activity, thrombin-antithrombin complexes (TAT) and D-dimers were collected initially and on days 1, 3, 5 and 7 of storage. Consumption of glucose, pH and concentrations of lactate dehydrogenase (LDH) and ATP were determined to investigate the metabolic status of the PC. The decrease in pH correlated to the leucocyte count, r = -0.74, P < 0.001 and to the increase in LDH, r = -0.74, P < 0.01. The levels of elastase and the SPA were consistently low in the PPP bags. In the PC elastase had increased by day 5 and the SPA by day 3; the levels in PC A were significantly higher than in PC B, P < 0.01. The leucocyte count correlated with the elastase activity, r = 0.71, P < 0.01, and with the SPA, r = 0.65, P < 0.01. A minor increase in FPA was demonstrated while no TAT and D-dimers could be detected. The cause of the formation of FPA was studied in experiment 2; three bags of PC and four of PPP were prepared from each of 16 donors. To the PC and three of the PPP bags either hirudin, aprotinin or no enzyme inhibitor (control) was added.(ABSTRACT TRUNCATED AT 250 WORDS)

Antithrombin III↗

PubMed1992

Blood component processing technique and plasma quality.

To maintain a closed system during the preparation of blood components, including the removal of buffy coat, many centers use a quadruple blood bag additive solution system which in this study has been reduced to a cheaper triple bag system. The buffy coat and plasma were after centrifugation transferred to the first satellite bag and, after a second spin, the plasma separated from the buffy coat was transferred to the second satellite bag and stored for a fortnight at 4 degrees C. This resulted in a statistically significant increase in platelet factor 4 and elastase activity levels. No significant changes were found in the levels of C1-esterase inhibitor and kallikrein inhibiting activity, thrombin-antithrombin complexes, soluble fibrin, fibrinopeptide A and spontaneous proteolytic activity. The changes observed must be regarded as clinically insignificant. The platelet count is low enough to meet the requirements for platelet poor plasma. Using this blood component separation technique, one can reduce the CPD/additive solution 4-pack blood bag system to a less expensive 3-pack blood bag system.

Blood Banks↗

PubMed1992

Freezing technique and quality of fresh-frozen plasma.

Cell-poor plasma was prepared by apheresis from 10 donors. From each donor, an amount of 200 ml was frozen rapidly to -40 degrees C in standard blood bags, and a further 200 ml was frozen slowly to -20 degrees C. Before freezing and after thawing, plasma samples were collected and frozen to -70 degrees C pending analysis. Coagulation factor VIII activity was reduced to 90% by rapid freezing and to 80% by slow freezing. Factor V was not influenced by rapid freezing, but slow freezing reduced the levels to 92% of the pre-freezing levels. In some of the plasma bags a slight increase in fibrinopeptide A occurred. However, soluble fibrin, thrombin-antithrombin complexes and spontaneous proteolytic activity were not altered by freezing. The beta-thromboglobulin increased slightly with slow freezing. Moreover, in a separate experiment, evaluating the possible effects of refreezing plasma samples, an increase in beta-thromboglobulin was also recorded, while the levels of factors VIII and V and von Willebrand factor were not affected. The changes in some variables, which were recorded in the cell-poor plasma, frozen soon after the blood donation at a slow freezing rate, must be regarded as insignificant in most clinical situations.

Antithrombin III↗