Speed of Intracranial Clot Lysis With Intravenous Tissue Plasminogen Activator Therapy

SummaryAn international collaborative study involving ten laboratories located in eight different countries was undertaken in order to replace the current International Standard (I.S.) for tissue plasminogen activator (t-PA). Two lyophilised candidate preparations of high purity were assessed in comparison with the current I.S. for t-PA using only a clot lysis assay. One preparation (coded 861670) was purified from a cultured melanoma cell supernatant and was about 98% single chain t-PA while the other preparation (coded 861624) was derived from Chinese hamster ovary (CHO) cells following DNA recombinant procedures and was 75% single chain t-PA.Both candidate preparations of t-PA compared in quite a satisfactory manner with the current I.S. from the viewpoint of the biometrics of parallel line bioassays and both preparations were quite stable for long periods at low temperatures and stable from up to 1 month at temperatures of 20° and 38° C. Both fultil the criteria to serve as a satisfactory Znd International Standard for t-PA. The Fibrinolysis Subcommittee of the International Committee for Thrombosis and Haemostasis recommended the melanoma source t-PA (861670) as the next I.S. in order to maintain continuity with the 1st I.S. which was also a melanomatype preparation. The data from the ten laboratories indicated that each ampoule of the new proposed standard contains 850 international units of t-PA activity by the clot lysis assay. It is planned to present the results of this study to the Expert Committee on Biological Standardization of the World Health Organization at its next meeting and to request that the preparation of t-PA, coded 861670, be established as the 2ndlnternational Standard for t-PA.

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A Collaborative Study of a Proposed International Standard for Tissue Plasminogen Activator (t-PA)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661253 ◽

1985 ◽

Vol 53 (01) ◽

pp. 134-136 ◽

Cited By ~ 70

Author(s):

P J Gaffney ◽

A D Curtis

Keyword(s):

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Collaborative Study ◽

International Committee ◽

World Health ◽

Clot Lysis ◽

Expert Committee ◽

International Standard ◽

Tissue Plasminogen ◽

Health Organization

SummaryAn international collaborative study involving seven laboratories was undertaken to assess which of three lyophilised preparations might serve as an International Standard (I.S.) for tissue plasminogen activator (t-PA). Two of the preparations were isolates from human melanoma cell cultures while one was of pig heart origin. A clot lysis assay was used by all participants in the study.The data suggested that both preparations of human cell origin were comparable, in that their log dose-response lines were parallel, while that of the porcine preparation was not. Accelerated degradation studies indicated that one melanoma extract (denoted 83/517) was more stable than the other and it was decided to recommend preparation 83/517 as the standard for t-PA. The International Committee for Thrombosis and Haemostasis (Stockholm 1983) has recommended the use of this material as a standard and it has been established by the Expert Committee on Biological Standardization of the World Health Organization as the International, Standard for tissue plasminogen activator, with an assigned potency of 1000 International Units per ampoule.

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Faculty Opinions recommendation of Time to treatment with intravenous tissue plasminogen activator and outcome from acute ischemic stroke.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718021390.793479381 ◽

2013 ◽

Author(s):

Patrick Ray

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Time To Treatment ◽

Intravenous Tissue Plasminogen Activator ◽

Tissue Plasminogen

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PHYSICAL ACTIVITY RELEASES TISSUE PLASMINOGEN ACTIVATOR FROM EXERCISING PARTS OF BODY

10.1055/s-0038-1643117 ◽

1987 ◽

Author(s):

I Keber ◽

K Potisk ◽

D Keber ◽

M Stegnar ◽

N Vene

Keyword(s):

Physical Activity ◽

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Fibrinolytic Activity ◽

Venous Occlusion ◽

Clot Lysis ◽

Lysis Time ◽

Tissue Plasminogen ◽

Euglobulin Clot Lysis Time ◽

The Difference

To determine the origin of tissue plasminogen activator (t-PA) release during physical activity, we studied the separate and combined effects of venous occlusion and acute physical activity on t-PA release in arm and leg. In 15 healthy volunteers 20 min venous occlusions of arm and leg were performed simultaneously before physical activity ( maximal stress testing on treadmill)(occlusion I), immediately after physical activity and 45 min later (occlusion II). Blood samples were drawn from unoccluded arm before occlusion and after physical activity, and from occluded arm and leg after occlusion. Fibrinolytic activity was measured by euglobulin clot lysis time (ECLT) and t-PA activity assay. The amount of released t-PA during different stimuli (fibrinolytic potential) was calculated as the difference between post- and prestimulation fibrinolytic activity. Before physical activity there was a great increase in fibrinolytic activity due to t-PA in the occluded arm but no increase in the occluded leg. Physical activity itself caused a similar increase of systemic fibrinolytic activity as arm occlusion locally. After physical activity arm occlusion evoked equally good response than before it. Fibrinolytic activity during leg occlusion behaved differently: there was an increase in t-PA activity in the occluded leg which persisted one hour after physical activity, when systemic fibrinolytic activity already fell to initial level.These results demonstrated that walking and running triggered t-PA release from the leg vessels. Since leg occlusion was not a stimulus for t-PA release, it served only as a method to demonstrate the effect of physical activity.

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