The Platelet Monitoring System (PMS) and the Non-invasive Assessment of Platelet Shape and Concentration (NAPSAC) instruments which relate light scattering characteristics of platelet concentrates (PC) to platelet concentration and shape, were evaluated to determine their accuracy in assessing platelet quality during storage from 1 to 7 days. The results were correlated with platelet concentration, % discs and pH on 121 PC stored in PL732 containers. NAPSAC output is in the form of platelet concentration and % discs. When NAPSAC and standard method values were compared, correlation coefficients (r) did not exceed 0.76 for counts and 0.62 for % discs. PMS output is in the form of lights with red indicating poor quality and green or amber indicating acceptable quality. Sensitivity of the PMS instrument did not exceed 83% and specificity did not exceed 63%. Mean platelet number, % discs and pH were comparable for units triggering red versus green or amber lights. In a separate study, 13 PL732 PC stored 5 days and transfused autologously were evaluated on the PMS. Three red light units exhibited recovery and survival times similar to those observed with PC triggering green/amber lights. These data indicate that neither instrument adequately assesses the quality of PL732 PC.

Blood Platelets↗

PubMedDate not supplied

Inactivation of viruses in platelet suspensions that retain their in vitro characteristics: comparison of psoralen-ultraviolet A and merocyanine 540-visible light methods.

The ability of two fundamentally different photochemical procedures to inactivate model viruses in platelet suspensions was compared. Merocyanine 540 (MC 540) with visible light was used as an example of an oxygen-dependent chemical-directed at the viral membrane, and aminomethyl trimethyl psoralen (AMT) with ultraviolet A light (UVA) was used as an example of a nucleic acid-directed system. Antiviral conditions in petri dishes were identified and the effects of these procedures on platelet suspensions in plastic storage containers were studied. Concentrations of photochemicals in the 10 to 150 mumol range with 30 to 60 minutes of visible light (MC 540) or 1 to 2 minutes of UVA (AMT) readily inactivated 5 to 6 log10 of vesicular stomatitis virus (VSV) and other model viruses in platelet suspensions, provided the plasma concentration was reduced to about 15 percent by the use of a synthetic platelet storage medium. Extracellular pH, morphology scores, and aggregation response dropped markedly when platelets were treated with MC 540 and visible light. However, treatment with 136 mumol per L of AMT and 1 to 3 minutes of UVA could inactivate 5 log10 of VSV in platelet suspensions with retention of platelet characteristics for 4 days, particularly if oxygen levels were reduced during treatment. These studies demonstrate that AMT-UVA treatment meets the initial requirements for virus inactivation in platelet suspensions.

Blood Platelets↗

PubMedDate not supplied

[Does a specific withdrawal syndrome from non-dopaminergic antiparkinson agents exist?].

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Adult↗

PubMedDate not supplied

[Withdrawal of non-dopaminergic antiparkinson drugs].

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Adult↗