摘要:

In order to investigate changes in coagulation and fibrinolysis arising during and after laparoscopic surgery we studied 24 patients, who were operated on because of biliary lithiasis [21 females, three males, aged 36–69 (mean 50) years]. The reference group consisted of 17 patients, who were operated on traditionally [15 females, two males, aged 25–72 (mean 55) years]. Blood samples were taken from cubital vein 24 h prior to the operation, during the cholecystectomy, on the 1st and 3rd postoperative days. Additionally, before and during operation blood was sampled simultaneously from femoral vein. Both groups had similar perioperative values of platelet count, fibrinogen and t-PA Ag. Patients operated on laparoscopically had generally lower values of F1+2 and plasmin-α2-antiplasmin complexes, and intra-operative PAI-1 activity than those operated on traditionally. Test values in blood sampled simultaneously from femoral and cubital veins were not statistically different. The data obtained show that generation of thrombin and plasmin is lower in patients operated on laparoscopically compared with those having traditional surgery. Venous stasis during laparoscopic cholecystectomy in lower extremities does not cause local alterations in hemostasis.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Five patients with severe (type III) von Willebrand disease received, by continuous infusion, a solvent-detergent treated von Willebrand factor high purity concentrate to control haemostasis. The clinical indications for treatment included prophylaxis prior to orthopaedic, abdominal and tympanic membrane surgery, and treatment of epistaxis and trauma-related bleeding. Plasma vWf antigen and activity were normalized sooner than factor VIII:C levels after initial bolus followed by infusion of the concentrate. Haemostasis was established in all five patients. The degree of shortening of the bleeding time correlated with concentrate infusion rate and, therefore, with administered dose of high molecular weight multimers. Concentrate clearance decreased over time with continued infusion. The product was shown to be stable and sterile at 24 h after reconstitution with no evidence of neoantigen expression. This report illustrates the effectiveness of high purity vWf concentrate administered by continuous infusion and shows that high-molecular-weight multimers are required to shorten the bleeding time to within the normal range.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We studied five patients who developed a decrease in platelet count of more than 30 000 × 106/l within 24 h of heparin treatment and direct percutaneous transluminal coronary angioplasty and/or intracoronary thrombolytic therapy among 38 consecutive patients with acute myocardial infarction (AMI). Anti-platelet factor 4 (PF4)-heparin complex antibodies were detected in the sera of these five patients, although they had never previously been exposed to heparin. These patients might have had specific antibodies before heparin treatment. PF4 might be released from activated platelets and bind to endogenous heparin-like molecules, and antibodies with cross-reactivity to the PF4-heparin complex may have been generated by the endogenous complex before the first heparin treatment. We conclude that it is worthwhile to check the platelet count and screen for anti-PF4-heparin complex antibody in advance to prevent thrombotic complications due to heparin treatment in patients with AMI.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We investigated whether Hepchek™ heparin removal filters could remove residual platelets from platelet-poor plasma (PPP) without compromising samples for lupus anticoagulant (LA) testing. Furthermore we assessed what effect, if any, plasma filtration has on various clotting tests that form the foundation for LA testing. Citrated blood was obtained from 35 normal donors. Two sets of citrated tubes were processed in order to obtain PPP. Citrated blood was also obtained from a single donor to check the actual amounts of platelets removed by the Hepcheck™ filtration device. One set of PPP samples was filtered using the Hepchek™ filter device and the other was not processed, i.e. unfiltered. Prothrombin time (PT), activated partial thromboplastin time (APTT), and kaolin clotting time (KCT) were performed on both unfiltered and filtered samples that were tested immediately and after freezing at-70°C for 24 h. Platelet counts on the single donor's citrated plasma were dramatically reduced after filtration. PT and APTT values showed small but statistically significant differences between unfiltered and filtered plasmas whether these were fresh or frozen samples. However, these differences were not clinically significant. KCT data showed statistical and clinical differences between unfiltered and filtered plasmas whether fresh or frozen plasmas were used. In contrast, KCT values were similar if unfiltered, fresh plasmas or filtered, frozen plasmas were used. Coagulation factor assays for factors VIII, IX and X were performed on both sets of PPP samples after freezing to determine if the filtration device affected these levels and would as a result, compromise APTT based lupus testing. Factor IX levels demonstrated a loss of activity following use of the device but no change was observed in factor VIII or factor X. Von Willebrand factor antigen and function as well as multimer structure were not affected by the filtration device in 10 normal donors. Filtering plasmas of two donors with a history of an LA dramatically prolonged clotting times for APTT, Dilute Viper Venom Time, mixing studies, and STACLOT LA tests in comparison with unfiltered plasmas. The data indicate that plasma filtration using the Hepchek™ device does not adversely affect coagulation testing. Furthermore samples requiring testing for the lupus anticoagulant can be filtered and subsequently frozen and compare favorably with freshly processed samples.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Endothelial cells (EC) possess several protective thromboregulatory mechanisms that may be perturbed by cell activation or injury. Vascular ATP-diphosphohydrolase (ATPDase) has been demonstrated on both aortic EC and smooth muscle cells and may play a key regulatory role in hemostasis and platelet reactivity by converting extracellular ATP and ADP to AMP. We have examined the role of exogenous saturated or unsaturated tatty acids in the modulation of EC associated ATPDase activityin vitro.EC growth was not dramatically influenced by supplementation with fatty acids whereas viability was enhanced by oleic, butyrate and eicosapentaenoic acid. EC cultures supplemented with saturated or a monounsaturated (oleic acid) fatty acid(s) had markedly increased ATPDase activity, whereas those exposed to polyunsaturated fatty acids showed substantive decreases. Exogenous oleic acid could also protect against the significant loss of ATPDase activity, following exposure to reactive oxygen intermediatesin vitro.We conclude that endothelial ATPDase activity may be regulated by exogenous fatty acids and that underlying mechanisms include alterations in the nature of the phospholipid composition of EC membranes that influence responses to oxidative stress reactions.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

In this paper we describe the effect of activated protein C (APC) on thrombin generation initiated in platelet-poor plasma via the extrinsic or the intrinsic pathway. Thrombin was determined with a specific chromogenic substrate and quantitated by calculating the time integral of the thrombin generation curve, i.e. the endogenous thrombin potential (ETP). Addition of APC to normal plasma after both extrinsic and intrinsic initiation of coagulation resulted in a dose-dependent inhibition of thrombin generation as reflected by the decrease in ETP. Data obtained in intrinsically triggered plasma of normal individuals were subject to large variation. Therefore, the effect of APC on thrombin generation in APC-resistant plasmas was only studied in extrinsically stimulated reaction systems. APC had much less effect on the ETP of plasma from individuals that were heterozygous or homozygous for the mutation Arg506→ Gln506in factor V (APC resistance). There appears to be a linear relationship between the ETP and the amount of α2-macro-globulin-thrombin complex (α2M-IIa) that accumulates in plasma during thrombin formation. Since the α2M-IIa complex possesses amidolytic activity, we measured the effect of APC on thrombin generation via the so-called normalized APC sensitivity ratio (APC-sr). The latter was defined as the ratio of the end levels of amidolytic activity of the α2M-IIa complex determined in the presence and absence of 50 nM APC (α2M-IIa+APC/(α2M-IIa-APC) divided by the ratio of a normal plasma pool. Significant differences (P< 0.001) were observed between APC-sr of plasmas from normal individuals (APC-sr: 0.5–1.9,n= 25) and of plasmas from individuals that were heterozygous (APC-sr: 2.1–6.7,n= 17) or homozygous APC resistant (APC-sr: 3.9–5.9,n= 5). There was no overlap between APC-sr of normal plasmas and plasma from individuals, bearing the factor V mutation. Abnormal APC-sr in certain plasmas (pregnancy, use of oral contraceptives, anticoagulant therapy, protein S deficiency or lupus anticoagulant) were corrected by performing the assay on a plasma sample that was diluted 10-fold in factor V-deficient plasma. Our data show that measurement of the effect of APC on the ETP yields valuable information about the (pro)thrombotic status of plasma (e.g. APC resistance, pregnancy, use of oral contraceptives).

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Blood monocytes spontaneously activate endothelial cells in culture, leading to adhesion of monocytic cells onto the endothelial surface and overproduction of endothelial proteins such as von Willebrand factor (vWf) and plasminogen activator inhibitor type 1 (PAI-1). To overcome the difficulty in obtaining quiescent monocytes, we studied the ability of promonocytic THP-1 cells to activate endothelial cells. Lipopolysaccharide (LPS)-prestimulated and untreated THP-1 cells were cocultured with resting human umbilical vein endothelial cells (HUVEC) for 3 and 24 h in the presence of colimycin to neutralize LPS traces. Addition of untreated THP-1 cells had little effect on HUVEC adhesiveness. Addition of prestimulated THP-1 cells was followed by a noticeable adhesion after 3 h which reversed to basal values within 24 h. Under these conditions HUVEC adhesion molecules, E-sefectin, VCAM-1 and ICAM-1, were increased at 3 h with only ICAM-1 remaining overexpressed at 24 h. Diffusible endothelial proteins such as soluble E-selectin, PAI-1 and vWf to a minimal extent, increased in supernatants from HUVEC cocultured for 24 h with prestimulated THP-1 cells. In those cocultures, TNFα concentrations peaked at 3 h whereas IL-1β levels progressively rose until 24 h. Addition of an anti-TNFα antibody decreased by 40% E-selectin and ICAM-1 induction and suppressed PAI-1 overproduction with a weak effect on vWf. An anti-IL-1β antibody had negligible effects on HUVEC adhesion molecules, PAI-1 or vWf production. These results provide evidence that promonocytic THP-1 cells require prestimulation in order to activate HUVEC and that TNFα contributes to this phenomenon.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Monitoring of oral anticoagulant therapy is usually undertaken with the prothrombin time (PT), which is influenced by factors II, X, and VII. A number of studies have suggested that the prothrombin (factor II) level may be the most important determinant of the therapeutic efficacy of these drugs. Although some studies suggest that oral anticoagulants induce a similar residual level of plasma vitamin K-dependent proteins, others have called this into question. We therefore measured plasma levels of factors II, X, and VII in 50 patients undergoing chronic Warfarin therapy. The plasma levels of factors II, X, and VII were significantly different. Although the factor X levels of all plasmas were < 30%, levels of factors II and VII were > 30% in 14% and 50% of the samples, respectively. Multivariable analysis showed factor II levels to be the least significant of the three factors measured in determining the international normalized ratio of plasma or whole blood. Thus, plasma levels of the vitamin K-dependent coagulation factors are not equal in patients on chronic Warfarin therapy. If factor II (prothrombin) levels are indeed the major determinants of the therapeutic efficacy of Warfarin, alternative means of monitoring that more accurately reflects prothrombin levels should be evaluated.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We describe a case of a 70-year-old male who underwent coronary artery bypass surgery which was complicated by multiple thrombotic events associated with HIT. The thrombotic events were treated with intravenous argatroban (Novastan®). During the hospitalization the patient was found to require percutaneous bilateral renal artery revascularization for acute renal failure. The revascularization procedure was successfully accomplished with a high dose argatroban regimen. We present our report of a successful anticoagulation strategy during a peripheral intervention in a patient with HIT and the laboratory data which support this strategy.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Immune thrombocytopenic purpura (ITP) patients have characteristic anti-platelet antibodies in their circulation. To assess the interaction between such antibodies adhering on to a non-physiological surface and human platelets, normal anticoagulated blood was perfused over ITP patient plasma-coated surfaces in a parallel plate flow chamber. At 300 s-1, platelet adhesion to patient plasma-coated glass coverslips (24.0 ± 10%) was significantly higher than the adhesion to normal plasma-coated surfaces (9.8 ± 7%). When perfused at 1300 s-1, the adhesion to patient plasma-(5.1 ± 1.3%) and to normal plasma-(2.5 ± 1.2%) coated coverslips were significantly weaker. Furthermore, patient platelet binding depended on simultaneous contributions by antibodies and fibrinogen present on the plasma-coated surface, since adherence was antagonized both by normal immunoglobulins added to the perfusate, as well as by the anti-GPIIb/IIIa monoclonal antibody 16N7C2, which competes with fibrinogen for binding to its receptor on the platelet. Accordingly, platelet adhesion was only observed to coverslips coated with the plasma but not the serum of ITP patients. Hence, perfusion of normal platelets over surfaces coated with ITP patient plasma enables a functional assessment of the presence in this plasma of anti-platelet antibodies.

ISSN:0957-5235    

出版商:OVID    

年代:1997

数据来源: OVID