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Biomedical subjects

R A Kahn

Publications and source records attributed to R A Kahn.

151 records · Page 9Linked to original sources
PubMedDate not supplied

Recovery, lifespan, and function of CPD-Adenine (CPDA-1) platelet concentrates stored for up to 72 hours at 4 C.

We studied the in vivo recovery, lifespan, and hemostatic effectiveness of CPDA-1 platelet concentrates stored for up to 72 hours at 4 C. A total of 120 CPDA-1 concentrates containing an average (+/- 1 S.D.) of 6.6 +/- 2.0 x 10(10) platelets were prepared. The pH of the units following storage at 4 C was 6.8 +/- 0.2; no unit had a pH below 6.3. Autologous transfusion of six normal volunteers showed that platelets stored at 4 C for 72 hours had an in vivo recovery of 40 +/- 18 per cent and a lifespan of 5.1 +/- 1.5 days. The hemostatic effectiveness of CPDA-1 platelets was determined by platelet counts and template bleeding time measurements in 10 thrombocytopenic patients. Patients receiving 48-hour-stored platelets had a four- to six-hour posttranfusion corrected platelet increment averaging 15,300 +/- 3,200/microliter which was 67 +/- 34 per cent of expected recovery. Four of the five patients transfused with this preparation showed an improved bleeding time. In contrast, three patients receiving 72-hour-stored platelets had a four- to six-hour posttransfusion increment of 5,800 +/- 2,400/microliter that was only 26 +/- 13 per cent of the expected recovery; furthermore, only one of these patients showed any correction of the bleeding time. These data indicate that CPDA-1 platelets are hemostatically effective when stored at 4 C for up to 48 hours.

Adenine↗
PubMedDate not supplied

Donor platelet response and product quality assurance in plateletpheresis.

Retrospective analysis of 352 donors who underwent plateletpheresis at least four times, each using the Haemonetics Model 30 Blood Processor, indicated that a postpheresis platelet count of less than 100,000/microliter occurred in only 2.7 per cent of phereses. Restricting pheresis to those with a prepheresis platelet count of greater than 150,000/microliter would have lowered this to 1.3 per cent and eliminated only 3.7 per cent of donations. The donors' platelet counts returned to baseline approximately four days and rebounded above baseline eight to eleven days after pheresis. To minimize the chance of a donor having a postpheresis platelet count less than 100,000/microliter, the prepheresis platelet count should be greater than 150,000/microliter. A platelet count greater than 150,000/microliter immediately following the previous pheresis can be used instead of the prepheresis platelet count. The yield was related to the prepheresis platelet count, number of cycles, sex, type of procedure (platelet or platelet-leukapheresis), and the yield recorded during an individual's previous procedures. Seventy-five per cent of plateletpheresis products contained more than 3.3 x 10(11) platelets. This might be a satisfactory standard for quality assurance.

Blood Donors↗
PubMedDate not supplied

Impact of the anticoagulant-preservative citrate-phosphate-adenine (CPDA-1) on blood services.

The introduction of CPDA-1, as opposed to CPD, has allowed blood banks to store red blood cells for up to 35 days. The Missouri-Illinois Regional Blood Services studied the impact of CPDA-1 in three areas: reduction in blood outdating, change in distribution pattern, and the potential increase in the age of the products transfused. Our eighteen month study showed a reduction in blood outdating from 7.9 per cent to 3.9 per cent. Additionally, each unit of blood was distributed less frequently (from an average of 1.21 to 1.08 times from collection to transfusion). At the same time there was only a small increase in the mean age of the products transfused. It is our conclusion that the benefits of CPDA-1 can be attained with limited impact on the age of the products transfused.

Adenine↗
PubMedDate not supplied

Survival and biochemical characteristics of stored red cells preserved with citrate-phosphate-dextrose-adenine-one and two and prepared from whole blood maintained at 20 to 24 degrees C for eight hours following phlebotomy.

Studies were conducted to evaluate the characteristics of red cells stored for 35 days following preparation from units of whole blood anticoagulated with citrate-phosphate-dextrose-adenine-one and two (CPDA-1 and CPDA-2) and maintained at 20 to 24 degrees C for 8 hours after phlebotomy. The mean (+/- 1 SD) 24-hour survival for transfused CPDA-1 autologous red cells with hematocrit levels of 78.1 +/- 2.3 percent was 78.0 +/- 8.1 percent (n = 9). The 24-hour survival of red cells from units preserved with CPDA-2 with hematocrit levels of 79.3 +/- 4.5 percent was 74.8 +/- 8.6 percent (n = 15). This difference in survival was not significant. Red cells from control units stored for 1 day showed a 24-hour survival of 91.9 +/- 4.2 percent (n = 7). During the 8-hour holding, red cell adenosine triphosphate levels increased by 15 to 25 percent in units drawn into both CPDA-1 and CPDA-2. After the initial 8-hour period, the red cell 2,3 diphosphoglycerate levels were 54 +/- 12 percent (mean +/- 1 SD) of initial levels in units drawn into CPDA-1 and 58 +/- 8 percent of initial levels in units drawn into CPDA-2. Following 35 days of storage, units of red cells prepared from whole blood drawn into CPDA-1 and CPDA-2 had comparable plasma cation and ammonia levels and similar amounts of cell-free hemoglobin. These data indicate that red cells can be stored satisfactorily for 35 days when prepared from whole blood held at 20 to 24 degrees C for 8 hours.

2,3-Diphosphoglycerate↗
PubMedDate not supplied

Ultraviolet irradiation of platelet concentrate abrogates lymphocyte activation without affecting platelet function in vitro.

We studied the effect of ultraviolet (UV) radiation on platelet concentrates. Samples irradiated at 310 mm for 30 minutes at a dose of 1782 J per m2 showed no loss of platelet function in vitro as determined by adenosine diphosphate, collagen, or ristocetin-induced aggregation. Lymphocytes isolated from irradiated units were unable to act as responders or stimulators in a mixed-lymphocyte reaction. These data suggest that UV radiation of platelet concentrates may result in a cell suspension that is unable to evoke an immunological response.

Adenosine Diphosphate↗