Removal of Phenolic Compounds from Mainstream Cigarette Smoke by Plasticizer

A series of compounds were applied as plasticizer in the cellulose acetate filter of cigarette. The data showed that the tested filters with proper plasticizers could effectively remove phenolic compounds from mainstream cigarette smoke. In the test models, Triethyl citrate (TEC) exhibited significant absorption capacity to phenolic compounds in cigarette smoke, and the removal efficiency exceeded 49% in contrast to triacetin. Similar result was obtained in different type of cigarette with TEC tips. The removal efficiency of phenolic compounds was significantly affected by the loading of TEC when the loading of TEC was less than 9 wt%. However, when the loading of TEC was between 9-15 wt%, the removal efficiency showed only slight difference.

The Influence of Different Filter Parameters on the Semivolatile Composition of Mainstream Smoke

The semivolatile fraction of cigarette smoke contains the most important aroma and taste compounds which contribute to the smoker's enjoyment. Obviously, the semivolatile composition is strongly affected by cigarette filters and consequently by the material which is used for filter manufacturing. We have studied the effect of cellulose acetate and polypropylene as filter material on the smoke semivolatiles. Further, the effect of other parameters like pressure drop and the use of additives has been investigated. Smoke condensate was collected on a Cambridge filter pad, the semivolatiles were evaporated using a headspace apparatus and subsequently collected in a cold trap. Semivolatile analyses were performed by high-resolution GC/MS. The cellulose acetate filter, due to its polar structure, selectively retains polar compounds such as phenols and furans while the non-polar polypropylene filter shows a non-selective retention behaviour. The addition to polypropylene filters of a polar compound such as triacetin, which is used as plasticiser in the manufacturing of cellulose acetate filters, does not affect the retention behaviour towards the semivolatiles.

Clinical experience with transfusion of leukocyte-poor platelet concentrates prepared by filtration with prostacyclin

Repeated transfusions with platelets from randomly selected donors lead to HLA alloimmunization in about 50% of patients due to lymphocyte contamination of platelet concentrates. Attempts to remove the leukocytes from the platelet concentrates by additional centrifugation steps led to substantial loss of platelets. We report a new procedure for removal of almost all leukocytes with excellent platelet recoveries. Single donor concentrates are treated with 50 ng/mL prostacyclin to inactivate the platelets transiently. The concentrates are then passed through a cellulose-acetate filter to remove the leukocytes. In 30 concentrates this treatment reduced the contamination by leukocytes to less than 0.1 million per concentrate with a platelet recovery of 89% +/- 1% (mean +/- SEM). Thirty filtered platelet concentrates transfused to ten thrombocytopenic patients within one hour after filtration were well tolerated and led to corrected count increments of (22.0 +/- 1.1) X 10(6)/mL blood after one hour and normal survival thereafter. In four of five patients these concentrates reduced the bleeding time. We conclude that transient inactivation of platelets by prostacyclin enables optimal removal of leukocytes and may help to reduce alloimmunization during frequent transfusions with platelet concentrates.

Clinical experience with transfusion of leukocyte-poor platelet concentrates prepared by filtration with prostacyclin

Repeated transfusions with platelets from randomly selected donors lead to HLA alloimmunization in about 50% of patients due to lymphocyte contamination of platelet concentrates. Attempts to remove the leukocytes from the platelet concentrates by additional centrifugation steps led to substantial loss of platelets. We report a new procedure for removal of almost all leukocytes with excellent platelet recoveries. Single donor concentrates are treated with 50 ng/mL prostacyclin to inactivate the platelets transiently. The concentrates are then passed through a cellulose-acetate filter to remove the leukocytes. In 30 concentrates this treatment reduced the contamination by leukocytes to less than 0.1 million per concentrate with a platelet recovery of 89% +/- 1% (mean +/- SEM). Thirty filtered platelet concentrates transfused to ten thrombocytopenic patients within one hour after filtration were well tolerated and led to corrected count increments of (22.0 +/- 1.1) X 10(6)/mL blood after one hour and normal survival thereafter. In four of five patients these concentrates reduced the bleeding time. We conclude that transient inactivation of platelets by prostacyclin enables optimal removal of leukocytes and may help to reduce alloimmunization during frequent transfusions with platelet concentrates.

CLINICAL EXPERIENCE WITH TRANSFUSION OF LEUKOCYTE-POOR PLATELET CONCENTRATES PREPARED BY FILTRATION WITH PROSTACYCLIN

Repeated transfusions with platelets from randomly selected donors lead to HLA alloimmunization in about 50% of thepatients. This is caused by lymphocytes that contaminate the platelet concentrates. Attempts to remove the leukocytes from the platelet concentrates by additional centrifugation steps lead to substantial loss of platelets.We report here a new procedure for removal of almost all leukocytes with excellent platelet recoveries. Single donor concentrates are treated with 50 ng/ml prostacyclin in order to inactivate the platelets transiently. The concentrates are then passed through a cellulose acetate filter to remove the leukocytes. In 30 fresh concentrates this treatment reduced the contamination by leukocytes to less than 0.1 million per concentrate with a platelet recovery of 89± 1% (mean ±SEM). In concentrates stored for 3 days the contamination was reduced to about 5 million per concentrate. Thirty filtered platelet concentrates, obained from single donors by platelet apheresis using a Haemonetics U 50, were transfused to ten thrombocytopenic patients within 1 hour after filtration and were well tolerated. No signs of hypotension or other side effects were observed. The transfusions led to corrected count increments of (22.0±1.1) x 10 per ml blood after one hour and normal survival thereafter. In four out of five patients these concentrates reduced the bleeding time.We conclude that transient inactivation of platelets by prostacyclin enables optimal removal of leukocytes and may help to reduce alloimmunization during frequent transfusions with platelet concentrates.Supported by the Praeventionfund (grant 28953), The Hague.