Biomedical subjects
Publications and source records attributed to M B Simpson.
Samples of reconstituted frozen red blood cells, maintained at 4 C for 72 hours prior to culture, revealed a bacterial contamination rate of less than 0.2 per cent, suggesting that the present shelf life of 24 hours may be safely extended to 72 hours.
There is considerable controversy as to whether antigens of the Rh, Duffy, Kidd, Kell, or Lutheran red cell systems are present on human platelets. The majority of previous investigators of this topic have reported them to be present. We have used a sensitive two-stage radioimmunoassay to examine human platelets for the presence of antigens of these five red cell systems. Platelets from donors of appropriate red cell phenotype were incubated with monospecific anti-erythrocyte IgG, followed by a second-stage incubation with 125I-labeled mouse IgG monoclonal anti-human IgG (Fc). Analysis of ligand bound per cell demonstrated no significant difference in binding of erythrocyte antibodies to platelets from donors homozygous, heterozygous, or negative for D, C, c, E, e, Fya, Fyb, Jka, Jkb , K, k, and Lub antigens. These findings indicate that major antigens of the Rh, Duffy, Kidd, Kell, and Lutheran systems are not expressed on the surface of human platelets.
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We measured changes in A, B, 2H, PlA1, and HLA Class I antigens on human platelets stored as routine platelet concentrates (PCs) in 50 to 60 ml of citrate-phosphate-dextrose-adenine (CPDA-1) plasma in polyolefin (PL 732) bags at 22 degrees C with continuous cartwheel rotation. Samples were obtained at 1, 3, 5, and 10 days of storage; incubated with human IgG anti-A, -B, -HLA and -PlA1; incubated with mouse monoclonal 125I-labeled anti-human IgG; centrifuged through phthalate ester oils; and assayed in a gamma scintillation counter. Additionally, group O platelets were analyzed using 125I-labeled IgM mouse monoclonal anti-Type 2H. Mean values for molecules of Ig bound per platelet showed that platelet surface antigens A, B, 2H, PlA1, and HLA Class I showed no significant change during 10-day storage as routine PCs in CPD-A1 in PL 732 bags. Identical radioassays were performed with platelets incubated at 22 degrees C in plastic test tubes for 24 hours in homologous plasma from donors negative for the respective antigens and in a variety of artificial media with albumin and lipids. No significant changes occurred in any of the surface antigens, except for the loss of approximately 50 percent of the blood group A antigen from platelets stored in O plasma or in albumin media. These data indicate that HLA, PlA1, and type 2H structures do not readily dissociate from the platelet membrane during storage, while some blood group A antigens, presumably acquired passively from the plasma, will elute from the platelet under certain conditions. Routine storage conditions are unlikely to alter the immunogenicity of platelets due to a loss of antigen expression.
A sensitive and specific radioimmunoassay was used to determine whether human platelets possess antigens of the MNSs blood group. Mouse monoclonal IgG anti-M and anti-N were purified by Staphylococcus protein A chromatography, labeled with 125I, and incubated with platelet pellets from donors of various MN phenotypes. Human IgG anti-M, -S, and -s were purified by absorption-elution, incubated with platelet pellets from donors of different MNSs phenotypes, washed, and incubated with 125I-labeled mouse monoclonal anti-human IgG. In both assays, the platelet pellets were centrifuged through phthalate ester oils and the radioactivity in the pellets was counted. Dose-response curves and ligand bound per cell indicated no significant difference in the binding of mouse or human anti-M and anti-N to platelets from donors of the MM, MN, or NN phenotype or of human anti-S and anti-s to platelets from donors of the Ss or ss phenotype. Contrary to many previous studies, our data indicate that the MNSs antigens are not expressed on the circulating human platelet. Therefore, antibodies to these antigens probably do not play a role in refractoriness to platelet transfusion.
Prospective-concurrent audits and medical consultation were associated with a 56 percent decrease in the use of platelet concentrates at a tertiary care medical center. This study documents that mandatory pretransfusion review of component requests can alter hospital transfusion practices.
A semiautomated saline wash procedure using a blood cell processor was evaluated as a technique for removing plasma from platelet concentrates. In vitro studies demonstrated 92 to 99.6 percent (mean, 96%) removal of total plasma protein (n = 30) with 84 to 97 percent (mean, 90.8%) platelet recovery (n = 28) in post-wash units. Post-wash pH values changed by +0.2 to -0.86 (mean, -0.47) (n = 30); the level of recovery from hypotonic shock was 69 to 97 percent (mean, 86%) (n = 11) of pre-wash units; weighted morphology scores decreased from a mean of 248 to 223 (n = 9). Aggregation response to arachidonic acid, collagen, and adenosine diphosphate plus epinephrine showed essentially no change following the wash procedure, and electron microscopy demonstrated slight morphologic alteration. Autologous platelets labeled with indium-111 demonstrated 43 +/- 20 percent recovery (n = 11) for washed units, compared to 41 +/- 10 percent for control unwashed units (n = 5); mean survivals were 140 +/- 41 hours (n = 11) for washed platelets and 185 +/- 28 hours for unwashed units (n = 5). Thirteen alloimmunized patients receiving 55 washed platelet concentrates demonstrated a mean 1- to 4-hour corrected count increment of 3.99 X 10(3) per microliter, compared to 3.02 X 10(3) per microliter for 77 unwashed platelet units given to the same patients. This study documents that platelet concentrates maintain viability and efficacy following a semiautomated saline wash method using the Cobe 2991 Blood Cell Processor, a technique that may be helpful for patients who require plasma-depleted platelet transfusions.
We conducted a retrospective review of 155 spinal operations at our institution to determine the efficacy of intraoperative salvage. Addition of intraoperative salvage had little effect on the success of a preoperative autologous donation program. Only patients with operative blood loss > 2,000 ml (12% of patients) benefited from this expensive source of autologous blood. The technique tended to be most effective in children aged 16-18 years. Use of intraoperative salvage for all pediatric spinal procedures is neither necessary nor cost effective.