Biomedical subjects

G Moroff

Publications and source records attributed to G Moroff.

58 records · Page 4Linked to original sources

PubMedDate not supplied

Evaluation of two instruments for noninvasive platelet concentrate quality assessment.

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

Effect of an 8-hour holding period on in vivo and in vitro properties of red cells and factor VIII content of plasma after collection in a red cell additive system.

Extension of the holding time for whole blood units from 6 to 8 hours at ambient temperature should provide enhanced flexibility in the preparation of platelet concentrates (PCs). A paired study was conducted to evaluate the characteristics of stored red cells (RBCs) and plasma prepared from whole blood collected into a red cell additive system (CPD-ADSOL) after an extended holding time. An individual donated a unit of whole blood on two occasions; 1 unit was held for 6 hours before processing and the other for 8 hours. Autologous RBC 24-hour survival levels after 42 days of storage were comparable. Laboratory A, using a 99mTc-51Cr technique, found mean survival levels of 79 percent (6-hour hold) and 78 percent (8-hour hold) (n = 8). Analysis by the single-label procedure found the mean levels to be 82 and 81 percent. Laboratory B, using an albumin 125I-51Cr technique, found mean survival levels of 74 and 72 percent (n = 10). Mean hemolysis and ATP levels were found to be comparable after 42 days of storage following 6- and 8-hour holding periods. 2,3 DPG levels were reduced to a greater degree during the longer hold. The factor VIII levels in plasma frozen for at least a month after 6- and 8-hour holding periods were comparable; thawed plasma contained mean levels of 0.77 and 0.76 units per mL (n = 21). These studies indicate that components prepared by using a CPD-ADSOL system after holding periods of 6 and 8 hours have comparable properties.

Blood↗

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

Bacteria levels in components prepared from deliberately inoculated whole blood held for 8 or 24 hours at 20 to 24 degrees C.

BACKGROUND: An increase from 8 to 24 hours in the time that units of whole blood can be held at room temperature after phlebotomy would give blood centers more flexibility in component manufacturing and might allow receipt of many infectious disease test results prior to component preparation. However, the potential for bacterial growth during prolonged holding periods requires further study. STUDY DESIGN AND METHODS: In the Phase I study, 2-unit pools of ABO-identical whole blood were deliberately inoculated on Day 0 with Staphylococcus aureus or Pseudomonas fluorescens. They were then divided in half and stored at 20 to 24 degrees C. Red cells (RBCs) with additive solution, platelet concentrates (PCs), and frozen plasma were prepared after 8 and 24 hours. Bacteria levels in PCs and RBCs were monitored on Day 1; bacteria levels were measured in plasma after thawing. In the Phase II study, the same basic design as in Phase I was used, except that 10 bacterial species were studied, lower inocula were used, and RBCs prepared after a 24-hour room-temperature whole-blood hold were white cell-reduced by filtration. Bacterial growth was monitored during 42-day storage of RBCs (1 - 6 degrees C) and 5-day storage of PCs (20 - 24 degrees C) and after thawing of frozen plasma. RESULTS: For Phase I, significantly higher bacteria levels were observed in RBCs prepared after a prolonged hold (p < 0.05); higher levels were not observed in PCs and thawed plasma units. In Phase II, prior to white cell reduction by filtration, 8 of 10 organisms had significantly higher levels in RBCs prepared after a 24-hour hold than in RBCs prepared after an 8-hour hold, when both were examined on Day 1 (p < 0.05). For seven of eight organisms examined on Days 1, 21, and 42, filtration (white cell reduction) reduced the bacteria in RBCs prepared from 24-hour whole blood units to those levels found in unfiltered RBCs prepared from whole blood units held at 8 hours. A prolongation of the holding time from 8 to 24 hours resulted in significantly lower bacteria levels (p < 0.05) in PCs early in storage (Days 1, 1 - 2, or 1 - 3) for seven organisms, with no significant difference for two organisms, and a small but significant increase for one organism (Day 3, p < 0.05). There was no difference in bacteria or endotoxin levels in thawed units of plasma prepared from whole blood after 8- or 24-hour holding times. CONCLUSION: The levels of bacteria present in components after deliberately inoculated whole blood units are held for 8 and 24 hours depended on the organisms tested, the whole-blood holding period, and the blood component assayed; for RBCs, they also depended on whether WBC reduction by filtration was performed.

Bacteremia↗