cold apheresis platelets in pas

Conditions: Platelet Transfusion

Summary: this is a platelet transfusion study. the purpose of this study is to measure the life span and quality of platelets stored in a refrigerator. participants will give platelets by apheresis. platelets will be stored for 3 -20 days. a small portion of the subject's own stored platelets will be tagged with a radioactive isotope and infused back into the participant. this will enable us to track how many transfused platelets survive after storage in the refrigerator.

a single hyperconcentrated apheresis platelet unit will be collected from a healthy adult volunteer subject using the trima accel® automated blood collection system. concurrent plasma will be collected. the platelet unit will be stored, not-agitated, for up to 20 days at 4°c in a suspension of 35% plasma and 65% pas (platelet additive solution). at the end of the storage period, the subject will return to receive an 111indium oxine (indium 111, in-111) radiolabeled aliquot of their 4°c stored platelets. follow-up samples from the subject will be collected approximately 2 hours post-infusion and on days 1 (2x), 2 (2x), and 3 to calculate recovery and survival of the subject's 4°c stored platelets. the day 1 and day 2 the sample draws will be 2 - 10 hours apart. in addition to radiolabeled platelet recovery and survival measurements, various in vitro assays will be performed on the day of collection at the end of 4°c storage. one week after the infusion of the radiolabeled aliquot, the subject will return to receive a second radiolabeled aliquot of fresh platelets. to facilitate this, on the morning of the second infusion, the subject will return for collection of a 43 ml blood sample. the blood will be processed to obtain a fresh sample of the subject's platelets to serve as a control comparator. the platelets will be radiolabeled with in-111. the subject will return later in the day for infusion of the radiolabeled fresh 'control' comparator aliquot. follow-up blood samples will be drawn at \~2 hours after the infusion on day 0 and then on days 1, 2, 3, 4 or 5, and 6 or 7 day post infusion to calculate recovery and survival of the subject's fresh vs. stored platelets.

Eligibility criteria:
inclusion criteria: * weight: ≥ 110 pounds * platelet count: ≥ 150x10\^3/ml * hematocrit: 38% for females, 39% for males, but not \>55% * temperature: ≤ 99.5 f * resting blood pressure: systolic ≤180 mmhg; diastolic ≤ 100 mmhg * resting heart rate: 40 to 100 beats per minute * subjects must be: at least 18 years old, of either sex * subjects must be able to read, understand and sign the informed consent document and commit to the study follow-up schedule. the ability to read and speak english is required for participation. * subjects must have good veins for apheresis platelet collection and drawing blood samples. * subjects of child-bearing potential (either male or female) must agree to use an effective method of contraception during the course of the study. the following methods of contraception are be considered effective; abstinence, intrauterine contraception devices, hormonal methods, barrier methods or history of sterilization. exclusion criteria: healthy subjects will be excluded from the study for any of the following reasons: * unable to achieve target platelet yield of 3.0 x 1011/unit per trima accel (apheresis machine) configuration parameters. * ever received radiation therapy. * already participated in 4 research studies involving radioisotopes within the contemporaneous calendar-year. * taken aspirin, non-steroidal anti-inflammatory, or other platelet affecting drugs within 72 hours of collection or infusion. subjects who have ever been prescribed anti-platelet medications (e.g. clopidogrel) will be excluded from study participation regardless of the interval to their last dose. * currently pregnant or nursing as assessed during interview. a urine pregnancy test prior to radioisotope infusion is required for women of childbearing potential. * unable to comply with the protocol in the opinion of the investigator. * donated granulocytes within the last 2 days. * donated whole blood within the last 7 days. * donated platelets or plasma within the last 28 days.

Keywords: platelets transfusion cold storage apheresis