Cellular contamination of plasma collected with various apheresis systems.

Efforts to improve the purity of blood products have mainly focused on reducing white blood cell (WBC) levels in cellular blood products. Relatively little attention has been given to the cellular purity of plasma. We evaluated plasma units collected on six apheresis systems: Dideco Excel, Haemonetics-MCS+, Fresenius-AS-Tech 204, Baxter-Amicus, Gambro BCT COBE Spectra and Gambro BCT-Trima. Collected plasma volumes averaged 300-350 ml for the various systems. Plasma samples were analyzed for platelet (PLT) content (Technicon H3, Bayer) and residual WBC (Imagn 2000). Results are given below. Platelet levels were consistently low for MCS+, COBE Spectra and Trima (all <50 x 10(3) microl(-1)), and were highest with AS204. Residual WBC levels were relatively low in all systems except MCS+. Extremely low levels were observed in Trima plasma. All of the Trima and Spectra units contained <1 x 10(6) WBC per product. With Excel, AS-Tech 204 and Amicus, 1 to 2 units were found to have >1 x 10(6) WBC, while almost all units from MCS+ exceeded this limit. Different levels of plasma purity were obtained with different apheresis systems. The Gambro BCT COBE Spectra and Trima systems were found to achieve consistently low levels of both platelets and WBC.

A new blood donation strategy: automated blood collection (ABC).

BACKGROUND: The aim of this study was to find out if Cobe Trima, a blood cell separator that automatically collects RBC, PLT and plasma, is adequate for routine multiple blood donation by apheresis. MATERIALS AND METHODS: Eighty donors underwent multiple blood component donations by Cobe Trima. Blood counts were determined on the apheresis products to analyze their quality. RESULTS: Eighty procedures were performed collecting 193 products. The average platelet yield was 3.5x10(11) (+/- 0.46) in the 54 single product (SP) procedures and 7x10(11) (+/- 0.88) in the 26 double product (DP) procedures. WBC contamination of the PLT products was 1.7 x 10(5) (1.2-4.2). The mean platelet efficiency was 60 +/- 8.35% for SP and 66 +/- 9.59% for DP. The hemoglobin (Hb) content per unit was 46.21 g (+/- 7.84) in 8 DP and 40.82 g (+/- 6.41) in 34 SP procedures. CONCLUSION: The production of standardized blood components with good PLT yield and low WBC contamination plus high efficiency makes Trima one of the best blood cell separators of the new generation.

Comparison of a new WBC-reduction system and the standard plateletpheresis protocol in the same donors.

BACKGROUND: A cell separator (Spectra, Gambro BCT) with an integrated leukoreduction system (LRS) for producing WBC-reduced single-donor platelet concentrates has been shown to result in a slightly reduced collection efficiency as compared to the former Spectra system without LRS. A novel modified system for improved collection efficiencies (LRS Turbo, Gambro BCT) was evaluated. STUDY DESIGN AND METHODS: Each of 37 donors underwent plateletpheresis using the LRS Turbo (LRS-T) and the standard LRS (LRS) of the Spectra cell separator. The collection efficiency and WBC contamination of the different techniques were compared. Platelets were counted automatically and WBCs were counted by using one or two full grids of a Nageotte chamber. RESULTS: The preseparation and postseparation numbers of RBCs, WBCs, and platelets, as well as the number of collected platelets, did not differ for the two techniques. In the LRS-T separations, the collection efficiency was 112 percent of that in the LRS procedures. Median residual WBCs in the platelet components were 0.0256 x 10(6) per LRS-T procedure and 0.0253 x 10(6) per LRS procedure. The purity of the LRS-T components was not less than that of the standard LRS components, whereas the collection efficiency of the LRS-T was significantly greater, 44.9 percent versus 40.7 percent. CONCLUSIONS: The LRS-T procedures produced platelet concentrates with WBC-reduction capacity that is comparable to that obtained with the standard LRS procedures, which have previously been described as satisfying the most stringent criteria for WBC-reduced platelets. The new technique significantly improved the collection efficiency of the plateletpheresis procedure.

Extrapolation of time series of EMG power spectrum parameters in isometric endurance tests of trunk extensor muscles.

The aim of the present study was to test the viability of using short isometric contractions of trunk extensor muscles to perform an assessment of their endurance capacity. To this aim two types of analysis were performed. First, electromyographic (EMG) mean power frequency (MPF) slopes with respect to time as estimated over shorter fixed periods were compared to slopes estimated over the full contraction period of a contraction sustained until the endurance time. Second, the relationship between MPF slope estimates as estimated over various periods and the endurance time of the muscle group was evaluated. Five subjects performed three isometric trunk endurance tests at 25%, 50% and 75% of their maximum voluntary contraction (MVC), respectively. EMG signals of the left and right multifidus, iliocostalis and longissimus muscles were continuously recorded and spectral parameters were calculated. The MPF appeared to decrease consistently during all endurance tests. The extrapolation from a MPF time series of half the estimated contraction period to the time series of the complete contraction period gave reasonable results at all force levels, when data from several electrode locations were incorporated in a single slope estimate (mean or steepest slope). The accuracy of the prediction of trunk extensor endurance on the basis of these parameters describing the MPF time series over half the estimated contraction period was satisfactory. Endurance time predictions from yet shorter periods were unreliable.