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Biomedical subjects

Harry Taylor

Publications and source records attributed to Harry Taylor.

5 recordsLinked to original sources
PubMed2006

Reevaluation of the resting time period when preparing whole blood-derived platelet concentrates with the platelet-rich plasma method.

BACKGROUND: The resting of platelet (PLT) pellets during the preparation of whole blood-derived PLT concentrates (PCs) is considered an essential step. A reevaluation of the rest period was conducted because preparation and storage conditions have been modified during the past 20 years. STUDY DESIGN AND METHODS: A two-site in vitro study (Study 1) was conducted with rest times of 0 to 5 minutes, 1 hour, and 4 hours (n = 31-33 per rest period). Leukoreduced PCs were stored for 5 days. A second study (Study 2) measuring in vivo viability was conducted at a third site (14 paired studies). PCs were prepared from 2 units of whole blood on the same day to simultaneously compare viability following storage and radioisotopic labeling. RESULTS: In Study 1, comparable in vitro parameters and swirling were observed with the three rest periods. The mean (+/-1 SD) values after storage for the extent of shape change and hypotonic stress parameters were 0 to 5 minutes, 16.7 +/- 7.2 and 66.0 +/- 15.7%; 1 hour, 19.1 +/- 6.9 and 69.3 +/- 17.9%; and 4 hours, 17.6 +/- 5.5 and 64.1 +/- 11.3%. In Study 2, the in vivo recovery was 49.9 +/- 15.3 and 50.9 +/- 20.2% with 0- to 5-minute and 1-hour rest periods, respectively. The corresponding survival time was 111.2 +/- 50.7 and 114.9 +/- 43.8 hours. CONCLUSION: These studies indicate comparable in vitro and in vivo viability properties with 0- to 5-minute and 1-hour rest periods and at 4 hours (in vitro only).

Anticoagulants↗
PubMed2005

Efficacy of apheresis platelets treated with riboflavin and ultraviolet light for pathogen reduction.

BACKGROUND: Pathogen reduction technologies for platelet (PLT) components offer a means to address continued viral transmission risks and imperfect bacterial detection systems. The efficacy of apheresis PLTs treated with riboflavin (vitamin B2) plus ultraviolet (UV) light (Mirasol, Navigant Biotechnologies) was investigated in a single-blind, crossover study in comparison to untreated PLTs. STUDY DESIGN AND METHODS: Normal subjects (n = 24) donated PLTs by apheresis on two occasions at least 2 weeks apart. Units were randomized to control or test arms, the latter receiving the addition of 28 mL of 500 micromol per L B2 and exposure to 6.2 J per mL UV light. PLTs were stored for 5 days with biochemical and hematologic analyses performed before and after illumination on Day 0 and at the end of storage. An aliquot of each unit was radiolabeled and returned to determine recovery and survival. RESULTS: The PLT content of treated units was maintained from Day 0 (4.1 x 10(11) +/- 0.4 x 10(11)) to Day 5 (4.0 x 10(11) +/- 0.4 x 10(11)). Treatment with B2 plus UV light was associated with an increase in lactate production with concomitant increases in glucose consumption. pH (control, 7.38 +/- 0.07; test, 7.02 +/- 0.10) was well maintained throughout storage. Recovery of treated PLTs (50.0 +/- 18.9%) was reduced from that of control PLTs (66.5 +/- 13.4%); survival was similarly shortened (104 +/- 26 hr vs. 142 +/- 26 h; p < 0.001). CONCLUSIONS: PLTs treated with B2 plus UV light demonstrate some alterations in in vitro measures but retain in vitro and in vivo capabilities similar to pathogen-reduced and licensed PLT components that have been shown to have useful clinical applicability. The recovery, survival, and metabolic properties of Mirasol PLTs should provide sufficient hemostatic support in thrombocytopenia to justify patient clinical trials.

Adult↗
PubMed2005

In vitro and in vivo evaluation of leukoreduced platelets stored for 7 days in CLX containers.

BACKGROUND: Extension of platelet (PLT) storage and concomitant use of a bacterial detection system would provide logistical advantages by reducing outdating and improving patient care through promotion of the use of sensitive detection systems. This study evaluated the in vitro characteristics and in vivo viability of leukoreduced PLT units derived from PLT-rich plasma stored for 5 days (control) versus 7 days (test) in CLX plastic containers. STUDY DESIGN AND METHODS: Two whole-blood units were collected from each subject into a leuko-reduction filtration system (Leukotrap RC-PL system, Pall Medical) in a paired design, the second 2 days after the first. These were leukoreduced (Leukotrap PL) and stored for 7 and 5 days. Poststorage samples from test and control units were randomly labeled with (51)Cr or (111)In and simultaneously infused autologously to determine recovery and survival. RESULTS: Small but significant (p < 0.05, paired t test) differences between 5 and 7 days of storage were seen in in vitro variables such as extent of shape change, hypotonic shock response, morphology, and P-selectin expression. In vivo recovery declined on average 11 percent with the two additional days of storage from 54.4 +/- 13.6 to 48.7 +/- 15.0 percent (p < 0.002); survival decreased on average 19 percent from 6.7 +/- 1.0 to 5.4 +/- 1.7 days (p < 0.002). CONCLUSION: Storage for 7 days was associated with reduced recovery and survival and in vitro variables, suggestive of extension of the storage lesion. These differences, however, were small in magnitude and unlikely to have significant clinical effects. Current collection and storage systems provide PLTs that are as functional at 7 days as those licensed for 7-day storage two decades ago.

Blood Platelets↗
PubMed2003

Collection of two units of leukoreduced RBCs from a single donation with a portable multiple-component collection system.

BACKGROUND: A portable automated component collection system that produces double (2) units of leukoreduced RBCs (DRBCs) from a single donation was evaluated. This study analyzed quality of the collected and final products, the efficacy of automated leukoreduction, and donor safety. STUDY DESIGN AND METHODS: The system was used to collect 120 DRBCs. WBCs were removed from 90 products with machine-controlled filtration. DRBCs were collected in ACD-A and stored in AS-1 for 42 days at 1 to 6 degrees C. Pre- and postprocedure donor vital signs and hematologic parameters were measured. Procedure time, product characteristics, and adverse events were also recorded. In vitro studies were performed on all products on Day 0 and at end of storage. In vivo recoveries of 28 leukoreduced and 9 nonleukoreduced products were measured on Day 42. RESULTS: Day 0 mean percentage of hemolysis for leukoreduced and nonleukoreduced units was 0.05 percent. DRBCs had residual WBC counts of less than 1 x 106 cells per unit and mean RBC recovery after filtration of 91.9 +/- 2.7 percent. Mean 24-hour recovery after infusion for leukoreduced units at end of storage was 80.9 +/- 6.9 percent and nonleukoreduced units was 77.6 +/- 5.8 percent (p> 0.05). No clinically significant changes in donor vital signs or serious adverse events were observed. CONCLUSIONS: The quality of leukoreduced RBCs collected with this portable automated component collection system met or exceeded FDA requirements. This automated system is safe and effective for collection and processing of 2 units of RBCs suitable for transfusion.

Blood Banking↗