Inconsequentiality of surface properties for initial platelet adhesion.
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Biomedical subjects
Publications and source records attributed to L I Friedman.
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The initial phase of a computerized on-line donor processing system was developed and demonstrated at the American National Red Cross, Washington Regional Donor Center and at bloodmobile operations. It was used for entry of donor registration information and for screening donors early in the donation procedure against a list of deferred donors. This demonstration took place with the computerized donor processing system running in parallel with the present manual operations. Since volunteer staff usually assist in the operation of most blood collection facilities, it was necessary to demonstrate that nontechnical personnel could operate the computerized system.
Units of whole blood were centrifuged for various periods of times and at various speeds to prepare platelet-rich plasma. It was found that several sets of centrifugation conditions resulted in an optimum yield of platelets and plasma. This optimum was approximately 8.3 x 10(10) platelets in 245 ml of plasma. When platelet-rich plasma was centrifuged, a maximum of approximately 95 per cent of the platelets could be recovered in the concentrate. Although this maximum was also achieved by several sets of centrifugation conditions, the most efficient method was 3,800 RPM (3731 x g) for four minutes at speed.
A continuous-flow filtration plasmapheresis system has been developed as an alternative to conventional techniques for conducting plasmapheresis from blood donors. The system was tested in two stages, nonreinfusion and continuous reinfusion. Donor safety, separation efficiency, and plasma quality were examined. These studies indicate that membrane plasmapheresis is feasible, safe to the donor, and yields sufficient plasma for either therapeutic or component therapy use.
A study was designed to test the hypothesis that cooling blood before it enters a continuous-flow blood cell separator would result in increased granulocyte yields. Fifty-four granulocyte collections performed with cooling were compared with 58 collections performed on alternate days in the same donors. In blood cooled to 15 degrees C we were unable to demonstrate improved yields of granulocytes.
The direct costs of ABO, Rh, Du, syphilis, and antibody screening tests were investigated. Questionnaires from 58 blood centers were analyzed to compare cost-effectiveness among methods of testing and annual collection volume as well as differences in cost of the various methods of testing within the same-size center. We found that "expensive" automated equipment cannot be justified on the basis of direct costs in centers processing less than 100,000 units of blood per year and that there is a wide variation in costs among centers using the same equipment.
A survey of the extent of automation and data processing in the blood banking community was conducted by questionnaire. The likelihood that a facility had some type of automation was related to the volume of blood products produced or transfused. Facilitates that collected blood or collected and transfused blood were more likely to have automation for ABO and Rh testing than those that only transfused blood. Automation for many other blood bank tests is unavailable. Many facilities had data processing capability, which is used primarily for accounting.
The safety of the nation's blood supply has improved over the last several years as a result of more intensive donor screening and viral testing. Concurrently, there has been more judicious use of blood components. Although the risk is small, transmission of blood borne viruses, bacteria and parasites can occur. Investigators have studied a myriad of processes for pathogen depletion and/or inactivation, including the use of chemicals, extended storage, filtration, heating, irradiation, photochemicals and washing. Pasteurization, methylene blue and solvent-detergent processes have been introduced in parts of Europe for improving the safety of plasma used for transfusion. The FDA is reviewing a license application for the solvent-detergent process. For red cells, use of highly efficient leukodepletion filters is believed to be equivalent to antibody testing for the prevention of CMV disease transmission. Otherwise, no successful treatments have yet been identified for red cells or platelets. Several photochemicals, which may be useful for treating these components, are being studied. However, there appear to be trade-offs between the extent of pathogen inactivation, platelet or red cell damage, and genotoxicity. These as well as other biological parameters and operational issues will need to be further evaluated before implementation can be considered.
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