PMID- 8292721
OWN - NLM
STAT- MEDLINE
DCOM- 19940228
LR  - 20061115
IS  - 0957-5235 (Print)
IS  - 0957-5235 (Linking)
VI  - 4
IP  - 5
DP  - 1993 Oct
TI  - Effects of low molecular weight heparins on fibrin polymerization and clot 
      sensitivity to t-PA-induced lysis.
PG  - 721-7
AB  - We have previously demonstrated that therapeutic concentrations of unfractionated 
      heparin (UFH) impair fibrin polymerization leading to the formation of clots 
      which are more sensitive to lysis induced by tissue plasminogen activator (t-PA). 
      The aim of this study was to compare the effect of UFH with that of three 
      different low molecular weight heparins (LMWHs) on clot sensitivity to 
      t-PA-induced lysis. Labelled fibrin clots, prepared from plasma containing UFH, 
      Fraxiparine, Reviparine, Enoxaparine or saline, were incubated in phosphate 
      buffer containing t-PA (0.1 and 0.5 microgram/ml) and plasminogen (20 
      micrograms/ml). The extent of clot lysis was quantified by counting the residual 
      radioactivity of the clots and by measuring D-dimer levels released into the 
      medium. Fibrin polymerization and clot structure were evaluated by means of a 
      turbidimetric assay and by electron microscopic scanning. Pre-incubation of 
      plasma with 0.5 or 1.0 U/ml UFH resulted in a marked dose-dependent acceleration 
      of lysis induced by 0.1 or 0.5 microgram/ml t-PA. In contrast, lysis rates 
      induced by 0.5 microgram/ml t-PA were not modified by pre-incubation of plasma 
      with LMWHs. When exposed to 0.1 microgram/ml t-PA clots formed from plasma 
      containing 0.5-2 IU/ml of Fraxiparine, Reviparine and Enoxaparine showed only a 
      minor increase in lysis rates compared to control clots. There was not a clear 
      dose-response curve with LMWHs. Furthermore, lysis rates obtained with 
      UFH-treated clots were always significantly higher than those seen with 
      LMWHs-treated clots.(ABSTRACT TRUNCATED AT 250 WORDS)
FAU - Parise, P
AU  - Parise P
AD  - Institute of Internal and Vascular Medicine, University of Perugia, Italy.
FAU - Morini, M
AU  - Morini M
FAU - Agnelli, G
AU  - Agnelli G
FAU - Ascani, A
AU  - Ascani A
FAU - Nenci, G G
AU  - Nenci GG
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - England
TA  - Blood Coagul Fibrinolysis
JT  - Blood coagulation & fibrinolysis : an international journal in haemostasis and 
      thrombosis
JID - 9102551
RN  - 0 (Enoxaparin)
RN  - 0 (Fibrin Fibrinogen Degradation Products)
RN  - 0 (Nadroparin)
RN  - 0 (Polymers)
RN  - 0 (fibrin fragment D)
RN  - 9001-31-4 (Fibrin)
RN  - 9005-49-6 (Heparin)
RN  - EC 3.4.21.68 (Tissue Plasminogen Activator)
SB  - IM
MH  - Blood Coagulation/*drug effects
MH  - Enoxaparin/pharmacology
MH  - Fibrin/chemistry/*metabolism
MH  - Fibrin Fibrinogen Degradation Products/metabolism
MH  - Fibrinolysis/drug effects
MH  - Heparin/*pharmacology
MH  - Humans
MH  - Microscopy, Electron, Scanning
MH  - Nadroparin/pharmacology
MH  - Nephelometry and Turbidimetry
MH  - Polymers/*chemistry
MH  - Tissue Plasminogen Activator/*pharmacology
EDAT- 1993/10/01 00:00
MHDA- 1993/10/01 00:01
CRDT- 1993/10/01 00:00
PHST- 1993/10/01 00:00 [pubmed]
PHST- 1993/10/01 00:01 [medline]
PHST- 1993/10/01 00:00 [entrez]
PST - ppublish
SO  - Blood Coagul Fibrinolysis. 1993 Oct;4(5):721-7.