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BACKGROUND: The importance of transfusing WBC-reduced blood components is widely recognized, as it reduces the risk of alloimmunization and transfusion-transmitted CMV infections. The latest generation of cell separators allows the collection of WBC-reduced apheresis platelet concentrates (APCs). MATERIALS AND METHODS: Consecutive APCs (n = 232) were retrospectively evaluated: 163 collected with the Spectra LRS [leukocyte-reduction system] Version 5.1 (Group A) and 69 with the LRS Turbo Version 7.0 (Group B) (both: COBE BCT). Donor peripheral blood count, procedure data, platelet yield, collection efficiency (CE), and residual WBC count in APCs were recorded. RESULTS: The platelet yield was higher in Group B than in Group A: 5.5 ± 1.4 versus 4.4 ± 1.1, p<0.0001; residual WBCs were <5 × 10 6 in 99.4 percent of Group A APCs and in 97.1 percent of Group B APCs. CE was higher in Group B than in Group A: 51.4 ± 8.7 versus 43.6 ± 6.3, p<0.0001. Moreover, a correlation between predonation platelet count and platelet yield was observed in both groups. A double product (platelet yield >6.0 × 10 11 ) was obtained in 28.9 percent of Group B APCs and in 9.2 percent of Group A APCs. CONCLUSIONS: The Spectra LRS Turbo version 7.0 release showed a better CE and resulted in a higher platelet harvest than did the LRS version 5.1. High predonation platelet counts allow a higher platelet yield.

Labeled and unlabeled (endogenous) free and phosphorylated thiamine were measured in isolated everted rings of rat jejunumin vitro during short incubation periods (1–10 min). Shortly after the addition of thiamine-14C to the incubation medium, the intracellular specific activity of the free form was higher than the specific activity of the phosphorylated fraction. In the course of time this difference diminished and finally the two specific activities became equal. The conclusion was reached that free thiamine is the likely precursor of intracellular phosphorylated thiamine.

In plasma of normal rats the presence of thiamine monophosphate, in a completely dialyzable form, was demonstrated by chromatographic procedures. Its content (16.2 ± 0.47 μg/100 ml) accounted for 64% of plasma total thiamine, the rest being free thiamine. Both thiamine compounds of plasma were rapidly and greatly affected by dietary thiamine deficiency. Administration of thiamine or its monophosphate by various routes apparently modified only the free thiamine content. Phosphorylated thiamine (most likely monophosphate) was present in the plasma of all the animal species studied.

Simple dietary thiamin deficiency (8 days) caused a greater decrease (68%) in free thiamin content in the brain than in thiamin phosphates (27%), without bringing about any neurological symptoms of athiaminosis. Injection of 0.03, 0.15 or 0.60 μmole of pyrithiamin into the brains of rats fed a thiamin-deficient diet caused an increase in free thiamin cerebral content in proportion to the dose injected. At the same time, the cerebral content of thiamin phosphates decreased. The oral administration of thiamin for 8 days (0.15 μmole daily) tended to cancel this modification.

In order to improve the process control of bedside filtration, a multisampling procedure was evaluated. Serial samples of postfiltration blood were collected, and white blood cells (WBCs) were counted by a microdroplet fluorochromatic assay. The kinetics of the bedside filter efficiency was shown to be nonlinear, with a saturation-like pattern owing to leukocyte escaping mostly during the second half of the filtration procedure. Multisample procedure allows the computation of the actual amount of filter-escaping leukocytes, while evaluation of filter-escaping leukocytes computed on the basis of a single-point sample (postfiltration terminal segment) may give misleading results and an overestimation of the number of filter-escaping WBCs.