Biomedical subjects
J L MacPherson
Publications and source records attributed to J L MacPherson.
Complications related to equipment and technique.
Automated cytapheresis, when performed by experienced operators using modern equipment, is remarkably free of adverse effects. A declining pattern of equipment failure and related problems has been recorded in the 220,000 procedures performed by the American Red Cross in the past 5 years. Other cytapheresis centers report similar findings. Current CBCS are safe and reliable, and defects in plastic disposables, while irritating, result in little danger to the donor. Operator vigilance and careful attention to the details of the procedure can eliminate the majority of serious potential complications that have been encountered to date.
The leukokinetic changes and complement activation associated with filtration leukapheresis.
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Inhibition of granulocyte erythrophagocytosis by HLA antisera.
The ability of HLA antisera to inhibit granulocyte erythrophagocytosis (EP) of opsonized red blood cells (RBC) was evaluated. Human granulocytes (PMN) were separated from heparinized whole blood by the Ficoll-Isopaque technique and suspended in McCoy's medium. EP occurred when the PMN were incubated with opsonized RBC. For six HLA antibody specificities evaluated, prior incubation of PMN with HLA antisera resulted in significant inhibition of EP without cytolysis when the PMN donor was positive for the specific HLA antigen, but not when the donor was negative for the antigen. The inhibition was time- and dose-dependent. Prior absorption of HLA antisera with HLA-specific platelets reduced or abolished the inhibition. An example of anti-NB1 also inhibited EP in 4 individuals. These data suggest that HLA antibody may adversely affect granulocyte phagocytic function. Inhibition of EP might be useful in evaluating compatibility prior to granulocyte transfusion.
Granulocyte bactericidal capacity and chemotaxis as affected by continuous-flow centrifugation and filtration leukapheresis, steroid administration, and storage.
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Nylon fiber leukapheresis: associated complement component changes and cranulocytopenia.
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Plateletpheresis using the haemonetics model 30 cell separator.
Plateletpheresis using the Haemonetics Model 30 cell separator results in a mean collection of 5.5 X 10(11) platelets. This product contains substantial numbers of erythrocytes and mononuclear cells which can be effectively removed by centrifugation but with a 23% loss of platelets as well. The mean decrement in donor's platelet count during the procedure, which is 78,000/mm3, is not commensurate with the number of platelets collected suggesting donor platelet mobilization. Platelets collected by this technic, when transfused into unselected recipients, give platelet increments comparable to platelets produced in the standard batch manner.
Granulocyte kinetics in donors undergoing filtration leukapheresis.
Normal blood donors undergoing filtration leukapheresis (FL) have a profound transient neutropenia early in the procedure which is followed by a "rebound" neutrophilia. This phenomenon occurs in unstimulated donors as well as in donors pretreated with either prednisone or dexamethasone. The mechanism for development of the neutropenia was investigated in volunteers throug a nylon filter at 37 C, a significant but transient neutropenia was observed. Plasma rendered cell and stroma-free achieved the same result indicating that plasma alone, when exposed to nylon fibers, is capable of producing neutropenia.
The acquisition of granylocytes by leukapheresis: a comparison of continuous flow centrifugation and filtration leukapheresis in normal and corticosteroid-stimulated donors.
Leukapheresis by continuous flow centrifugation (CFC) or filtration (FL) were compared in untreated and corticosteroid-treated donors. The administration of prednisone 60 mg orally 10 to 12 hours before leukapheresis increased significantly both the donor's prepheresis WBC counts and the total granulocyte yields by CFC or FL. Dexamethasone 6 mg iv at the start of FL did not increase granulocyte yields significantly. In untreated donors FL yielded 0.25 x 10(10) granulocytes per liter donor blood processed as compared with 0.05 x 10(10) per liter in CFC donors. Corticosteroid premedication has a greater relative effect in increasing yields by CFC than by FL. Donor reaction rates were between 4 and 6 per cent for both procedures.
Plateletpheresis residues: a source of large quantities of human blood lymphocytes.
The residue from single-donor plateletpheresis contains a large number of human mononuclear cells. We have been able to harvest more than 1 X 10(9) viable lymphocytes for laboratory study from the leukocyte-rich sediment that previously had been discarded. Prior to removal by adherence 5 X 10(8) monocytes were also available for future purification, if desired. The physical properties and response to phytohemagglutinin were very similar when lymphocytes isolated from plateletpheresis residues were compared with those obtained directly from veneous blood.
Abdominal pain in donors during filtration leukapheresis.
An unusual donor reaction characterized primarily by lower abdominal and/or perineal pain occurs in 1.2 per cent of donors during filtration leukapheresis (FL). The reaction occurs almost exclusively in female donors. Corticosteroid pretreatment appears to be highly effective in preventing the reaction. The pathogenesis of this donor problem is speculative.
Cryoprecipitated antihemophilic factor production from blood collected in quad packs or from blood with delayed processing. The importance of plasma thawing method.
Two alternate approaches to increasing the supply of plasma suitable for the production of cryoprecipitated AHF (cryo) were evaluated. In the first, cryo was prepared from blood collected in quadruple packs from which red cells and platelets also were made. This procedure resulted in a mean reduction of starting plasma volume of about 25 percent with a concomitant decrease in factor VIII coagulant activity (FVIII:C) of cryo when compared to approximately 2000 cryos made in triple packs assayed in our laboratory during the past year. However, American Red Cross (ARC) regions using a higher yield waterbath method of thawing plasma successfully produced quadruple pack cryos with a mean potency of 109 international units per container and about 90 percent of them met federal potency requirements. This was not the case for ARC regions using the lower yield method of thawing plasma in a refrigerator. The second approach involved cryo production from plasma frozen following 15 hours of cold storage of either the separated plasma or whole blood. Cold storage of plasma resulted in small but insignificant decreases in FVIII:C potency and yield in the cryo. However, there was a 20 percent decrease in FVIII:C yield in cryo produced from frozen plasma following 15 hours of cold storage of whole blood. Again, the decrease in FVIII:C yield resulting from interim blood storage was compensated for by the use of the higher yield waterbath method.
Application of biosafety principles in blood establishments.
In light of increasing public and employee concern over potential infectious hazards associated with blood and other body fluids, several government agencies (the Food and Drug Administration, the Centers for Disease Control, the Occupational Safety and Health Administration, the Environmental Protection Agency, the Health Care Financing Administration and the National Heart, Lung and Blood Institute) cosponsored a Biosafety Workshop in April 1988. The objective of the workshop was to identify appropriate biosafety practices and standard control procedures to protect workers involved in the collection, storage, and transportation of human blood donations with the least possible disruption of the nation's blood supply. Speakers focused on human immunodeficiency virus (HIV) and hepatitis B virus (HBV); however, the safety principles discussed were considered equally applicable to other known (e.g., non-A, non-B hepatitis and human T-lymphotropic virus type I (HTLV-1) blood-transmitted infections. The resulting consensus included the need for blood establishments to develop and apply thoughtful biosafety programs to address staff training, accident prevention, HBV vaccination, handling spills, managing contaminated waste and transporting blood specimens. There was lack of agreement, however, on the usefulness of gloves during the phlebotomy of healthy blood donors.
Markers for transfusion-transmitted disease in different groups of blood donors.
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