[Bedside pretransfusion compatibility testing fiability with cold agglutinins during cardiopulmonary bypass associated hypothermia for cardiac surgery]

This case report is an example of a bedside pretransfusion compatibility testing issue. An 81-years-old woman was admitted in the operating room for aortic valve replacement under cardiopulmonary bypass. A conflict occurred during the bedside pretransfusion compatibility testing between the results of the patient and the packed red blood cells. Afterwards, the patient was diagnosed with cold agglutinins. It might have produced false positive results with the anti-A and anti-B reagents.

Effects of clopidogrel and its inactive form, SR 25989, on plasma, liver and platelet lipids in the rat

The aim of the present study was to determine whether clopidogrel, one of the most potent antiplatelet compounds in vivo, could alter the lipid composition of plasma, liver tissue or platelet membranes in the rat. Animals treated (10 mg/kg per day for 7 days) with clopidogrel and its inactive analogue (R form, SR 25989) were compared with control animals. Neither compound altered plasma concentrations of triglycerides or free and esterified cholesterol, and no changes were observed in liver lipids. Clopidogrel treatment significantly lowered platelet cholesterol content and cholesterol to phospholipid ratio, while SR 25989 had comparatively smaller effects. Concerning platelet phospholipids, clopidogrel treatment reduced phosphatidylcholine(PC) but increased sphingomyelin (SP) content, whereas SR 25989 lowered PC and phosphatidylserine (PS) but raised phosphatidylethanolamine (PE) content. A significant increase in the arachidonic acid content of PE was observed only in the SR 25989 group. Clopidogrel and SR 25989 both induced an increase in the unsaturation level of platelet PC, accompanied by a decrease in the level of unsaturation in platelet SP, while a similar decrease was observed for phosphatidylinositol only in the clopidogrel group. These changes in platelet membrane composition in the clopidogrel group are probably unrelated to the antiaggregating properties of the drug, but could influence other platelet functions under long-term treatment.

Sensitivity and long-term prognostic value of cardiac troponin-I increase shortly after percutaneous transluminal coronary angioplasty

BACKGROUND

After successful coronary interventions, minor elevations of creatine kinase MB (CK-MB) identified a population with a worse long-term prognosis than that in patients without enzyme elevations. In that setting, cardiac troponin-I (cTn-I), a highly specific marker for myocardial injury, was considered for a small study; the results did not support the view that significant myocardial damage occurred during successful percutaneous transluminal coronary angioplasty (PTCA).

HYPOTHESIS

The present study was designed to assess the rate of elevated values of cTn-I after successful PTCA and to determine its prognostic value.

METHODS

CTn-I and CK-MB were measured in 44 patients before and daily for 3 days after PTCA. Two groups of patients were considered according to the presence or absence of elevated levels of cTn-I. The rate of free-event survival was estimated for the two groups using the Kaplan-Meier method and was compared with the log rank test.

RESULTS

Globally, 36% of patients had an increase in cTn-I (normal values 0.35 ng/ml) and 9% had an increase in CK-MB, p = 0.002. The mean time to maximal enzyme level was 1.8 days for cTn-I and 2.2 days for CK-MB. Over a follow-up of 1375 +/- 416 days, 18% of patients experienced adverse events, and cTn-I did not identify a population of worse long-term prognosis.

CONCLUSION

These results suggest that cTn-I is more sensitive than CK-MB in identifying minor myocardial damage after PTCA, but these elevated concentrations of cTn-I in the short-term aftermath of angioplasty do not seem to be a marker of worse long-term prognosis.

In vitro evaluation of Haemonetics MCS+ apheresis platelet concentrates treated with photochemical pathogen inactivation following plasma volume reduction using the INTERCEPT Preparation Set

Pathogen inactivation using the INTERCEPT Blood System requires platelet resuspension in InterSol and reduced plasma. Platelets in plasma collected on the Haemonetics MCS+ were processed on the INTERCEPT Preparation Set for plasma volume reduction and addition of InterSol. The use of the Preparation Set resulted in a mean platelet loss of 5.6 +/- 3.4%. Subsequent photochemical treatment (PCT) with amotosalen and ultraviolet A light, and 7 days of storage, resulted in acceptable changes for platelet swirling, lactate, lactate dehydrogenase (LDH), platelet factor-4 (PF4), p-selectin, glycoprotein V (GpV), pO2, pCO2, tumour necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8). All platelet units processed with the Preparation Set and PCT met European requirements for leucoreduction and pH values.

Effect of insulin on von Willebrand factor release in normal and diabetic subjects: in vivo and in vitro studies

The aim of this study was to evaluate the effect of insulin on the release of vWf in vivo during an oral glucose tolerance test (OGTT) performed in normal, glucose-intolerant and diabetic subjects and in vitro on human endothelial cells. Twenty-eight subjects exhibiting risk factors for diabetes underwent an OGTT: 11 subjects proved to be normal, 7 were glucose-intolerant and 10 diabetic. In each group, the vWf and PAI-1 plasmatic levels were measured at t = 0, 30 min and 180 min after the beginning of the test. Human endothelial cells from non-diabetic and diabetic subjects were incubated in the presence of human insulin at various concentrations (0.25, 2.5, 25 and 250 mUI/ml). After 1, 4, and 24 hours of incubation, the release of vWf and endothelin 1 was measured in the cell supernatant and the intracellular amount of vWf in the cell lysate. During the OGTT, the vWf levels in plasma were not affected despite a 4.5-, 6-, and 2.5-fold increase in insulin levels in normal, glucose-intolerant and diabetic subjects, respectively. Although raised in all three groups, PAI-1 plasmatic levels remained constant during the test. After 24 hours of exposure to insulin (0.25 mU/ml), the release of vWf by endothelial cells reached 35.94 +/- 23.08 % of the basal value for non-diabetic subjects, and 27.57 +/- 10.05 % for diabetic patients. Similar results were observed in non-stimulated cells. Insulin had no influence on intracellular vWf content, which remained comparable to control values. Regardless of its concentration, insulin failed to stimulate the release of vWf by endothelial cells of non-diabetic and diabetic subjects, while its ability to stimulate the release of endothelin 1 was preserved. In conclusion, hyperinsulinemia had no adverse effect on circulating vWf in normal or diabetic subjects. Neither release nor intracellular vWf content in non-diabetic or diabetic endothelial cells was influenced by insulin in vitro.

Long-chain n-3 fatty acids specifically affect rat coagulation factors dependent on vitamin K: relation to peroxidative stress

Fatty acids of marine origin have been shown to affect blood coagulation in the rat. In an attempt to gain insight into the mechanisms of this phenomenon, we studied the effects of dietary linseed and fish oils on the liver antioxidant status and plasma coagulation parameters in rats on a time-course basis. Dietary enrichment in eicosapentaenoic and docosahexaenoic acids resulted in strong hypocoagulation after only 1 week and a concomitant increase in liver lipid peroxidation and tocopherolquinone content. Enrichment in linolenic acid induced similar increases in lipid peroxidation and tocopherol catabolism but negligible alteration of coagulation. A significant correlation between plasma factor II coagulant activity and liver tocopherolquinone was found in fish oil- but not in linseed oil-fed rats. Although ingestion of tocopherolquinone led to high levels of this compound in the liver, it had only marginal effects on coagulation factors. Thus, it seems unlikely that this vitamin E metabolite could be involved in the lowering of vitamin K-dependent clotting factors through inhibition of gamma-glutamylcarboxylase. Rather, our results indicate that the effects of the n-3 fatty acids of fish oil on vitamin K-dependent coagulation factors are specific and independent of liver tocopherolquinone levels.

Antiphospholipid antibodies and preeclampsia: a case-control study

OBJECTIVE

To assess the association between the occurrence first of preeclampsia and antiphospholipid antibodies.

METHODS

We conducted a prospective case-control study of 180 pregnant women with their first incidents of preeclampsia and no histories of thrombosis or systemic autoimmune diseases. Preeclampsia (n = 180) was defined as blood pressure (BP) at least 140/90 mmHg after 20 weeks' gestation and proteinuria at least 0.3 g per 24 hours. Two control subjects were matched to each case (n = 360). They were pregnant women without hypertension or proteinuria and without histories of thrombosis or systemic autoimmune disease. Lupus anticoagulant (activated partial thromboplastin time, diluted thromboplastin time, platelet neutralization procedure) and anticardiolipin antibodies (immunoenzymatic assays) were assessed in both groups, and the coagulation state (levels of thrombin-antithrombin III complexes, fragments 1 + 2 of prothrombin) was also evaluated. The analysis design was a sequential plan with 5% type I error and 95% power.

RESULTS

There was no association between antiphospholipid antibodies and preeclampsia. The odds ratio for the association was 0.95 (95% confidence interval 0.45, 2.61). Antiphospholipid antibodies were detected in eight of 180 preeclamptic women and in 19 of 360 controls. In contrast, there was a clear, confirmed activation of coagulation during preeclampsia.

CONCLUSION

Despite evidence of a prothrombotic state during preeclampsia, it is unlikely that antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies) represent risk factors for preeclampsia among women with no previous preeclampsia and no histories of thrombosis or systemic autoimmune disease.

Cardiovascular morbidity and endothelial dysfunction in chronic haemodialysis patients: is homocyst(e)ine the missing link?

BACKGROUND

Haemodialysis patients exhibit an excessive burden of atherothrombotic disease, which is not explained adequately by traditional risk factors. Hyperhomocyst(e)inaemia, a consistent finding in uraemic patients, is now widely recognized as an independent risk factor for vascular disease. The aim of this study was to examine the hypothesis that hyperhomocyst(e)inaemia is associated with cardiovascular complications in dialysed patients.

METHODS

In a cohort of 63 stable chronic haemodialysis patients, we examined the causal relationship between hyperhomocyst(e)inaemia and vascular endothelial and haemostatic function. All their markers were determined before and after an 8-week course of a 10 mg per day oral folate supplementation, a manoeuvre known to decrease hyperhomocyst(e)inaemia in uraemic patients.

RESULTS

History of at least one cardiovascular atherothrombotic event was present in 47.6% of the haemodialysed patients, and radiographic evidence of vascular calcifications in 70%. Hyperhomocyst(e)inaemia was found in all patients, averaging 3.5-fold the upper limit of normal values (P<0.001), despite the lack of clinical and biological evidence of malnutrition. Fibrinogen, von Willebrand factor and plasminogen activator inhibitor type 1, but not endothelin 1, were significantly higher in haemodialysis patients than in controls. After adjustment for all variables, past history of cardiovascular events was independently associated with higher levels of homocyst(e)inaemia only (odds ratio (OR) 1.06; 95% confidence interval (CI) 1.01-1.12; P<0.026). The presence of aortic calcifications was independently and significantly associated with age (OR 1.37; 95% CI 1.07-1.75; P<0.025), homocyst(e)inaemia (OR 1.14; 95% CI 1.02-1.27; P<0.05) and fibrinogen concentration only (OR 9.74; 95% CI 1.25-75.2; P<0.05). None of the endothelial haemostatic factors was, however, related to homocyst(e)ine levels. Mid-term folate supplementation decreased plasma homocyst(e)ine levels significantly without achieving normal values. No significant change of endothelial-haemostatic markers was observed, however, despite the drop in plasma homocyst(e)ine.

CONCLUSIONS

Hyperhomocyst(e)inaemia is associated with increased cardiovascular risk in haemodialysis patients. Folate supplementation was partially effective in lowering hyperhomocyst(e)inaemia, but its usefulness in terms of reduction in cardiovascular morbidity and mortality remains to be determined in prospective trials.

Von Willebrand factor in diabetic angiopathy

Diabetes mellitus is a complex disease characterised by chronic hyperglycaemia responsible for complications affecting the kidneys, eyes, peripheral nerves and micro- and macrovascular systems. Von Willebrand factor (vWf), a multimeric glycoprotein mainly synthesised by endothelial cells, is involved in platelet adhesion and aggregation and acts as the carrier of coagulation factor VIII in plasma. Increased levels of vWf, reflecting activation of or damage to endothelial cells, have been described in association with atherosclerosis and diabetes. vWf appears to be a predictive marker of diabetic nephropathy and neuropathy, although not of retinopathy, which suggests that endothelial dysfunction precedes the onset of diabetic microangiopathy. This dysfunction could be especially involved in the pathogenesis of renal abnormalities of diabetes. vWf is not a predictive marker of macroangiopathy when diabetes is associated with atherosclerotic risk factors. In the presence of chronic diabetic complications, vWf levels are not associated with any grade of retinopathy but increase with the severity of nephropathy and would appear to be a risk factor for macrovascular mortality in these patients. The endothelial dysfunction of diabetes can generate atherosclerotic lesions responsible for damage to the arterial wall, atheroma and formation of platelet microaggregates. Concomitant with high vWf levels, other possible mechanisms of endothelial damage include reduced synthesis or release of nitric oxide, hyperglycaemic pseudohypoxia and protein kinase-C activation, increased synthesis of proteins bearing advanced glycosylation end-products or transforming growth factor-beta (TGF-beta) activation of coagulation and inhibition of fibrinolysis. At present, it is not known whether high vWf levels are inherent to the physiopathology of diabetes, nor whether diabetes induces endothelial dysfunction through other pathways. However, since angiopathy resulting from endothelial dysfunction is the main cause of morbidity and mortality in diabetic patients, appropriate therapy is necessary to reduce these complications. Glycaemic control seems to be insufficient to normalise plasma vWf, whereas a decrease can be obtained by ingestion of diets rich in oleic acid or by treatment with statins. Inhibition of the binding of vWf to the GPlba receptor by synthetic peptides, aurin tricarboxylic acid or monoclonal antibodies has been proposed to prevent the thrombosis induced by high levels of plasma vWf. Thus, vWf probably represents an interesting target for the inhibition of thrombosis in diabetes.

One-step assay for the determination of free protein S antigen in plasma using real-time biospecific interaction analysis

Real-time biospecific interaction analysis based on optical detection by surface plasmon resonance was used to develop an accurate one-step method for the direct measurement of free protein S in human plasma. This assay was validated, compared with classical immunological methods and shown to be suitable for the routine clinical diagnosis of protein S deficiency. The method relies on the specific capture of free protein S directly from plasma by a monoclonal antibody (mAb), 34G2, immobilized on a sensor chip surface. A calibration curve was established with serial dilutions of standard plasma (working range 5-50%) and a linear relationship was found to exist between the relative response in resonance units (RU) and the concentration of free protein S expressed as percentage plasma dilution (r = 0.99). The specificity of the assay was confirmed using purified human protein S and polyethylene glycol treated plasma. In addition, it could be demonstrated that no dissociation of C4b-BP-protein S complexes occurred under the chosen experimental conditions. The technique was reproducible with inter-assay, intra-assay and inter-sensor chip variation coefficients of 1.5-5.4%, 2-3.1% and 4.4-4.9%, respectively, as evaluated in two different plasma samples. Since all tests are automatic and long series of analyses can be performed with the same sensor chip, the method was applied to the determination of free protein S antigen in plasma from 20 normal blood donors and 38 thrombophilic patients. Results displayed excellent correlation with those of free protein S enzyme-linked immunosorbent assay (r = 0.99) and rocket immunoelectrophoresis of polyethylene glycol-treated plasma (r = 0.93).

Diets enriched in (n-3) fatty acids affect rat coagulation factors dependent on vitamin K

The effects of dietary lipids on haemostasis were investigated in rats fed high fat diets enriched in saturated fatty acids (SAT), oleic acid (OLEIC), MaxEPA oil (MaxEPA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) and results were compared to those for rats fed standard chow (ST). Coagulant activities of factor IIc and factor VII-Xc were reduced by about 70% in the MaxEPA group and 50% in the EPA and DHA groups relative to the OLEIC, SAT and ST groups. Liver vitamin K levels were five times lower in the experimental groups than in the ST group, which would indicate an effect of high fat diets on vitamin K metabolism. However, only (n-3) fatty acids prolonged the prothrombin time. These components could act at the post-translational modification level of vitamin K-dependent plasma clotting factors. The changes in haemostatic factors found in the MaxEPA group were counteracted by vitamin K supplementation.

Significance of diminished factor XIII in Crohn's disease

OBJECTIVE

Coagulation factor XIII is a plasma transglutaminase involved in crosslinking of fibrin, the last step of the coagulation system and a connective tissue factor contributing to the wound healing process. It circulates as a heterotetrameric molecule consisting of two identical proenzyme subunits (factor XIIIA) and two carrier protein subunits (factor XIIIS). The aim of this study was to determine the disease features associated with the diminution of factor XIII in Crohn's disease.

METHODS

Factor XIIIA and factor XIIIS levels were assessed in patients presenting with Crohn's disease, ulcerative colitis, infectious colitis, or diverticulitis, in patients with rheumatoid arthritis, and in control subjects. Prothrombin fragment 1 + 2 assay, as a marker of the generation of thrombin and measurement of C-terminal telopeptide of type I collagen as an estimate of degradation of collagen type I, were performed.

RESULTS

Factor XIIIA was significantly decreased in Crohn's disease, in ulcerative colitis, and in infectious colitis by comparison with subjects presenting with diverticulitis, normal, and rheumatoid subjects p = 0.0001). Factor XIIIS was unmodified in patients with Crohn's disease by comparison with controls but was reduced in those presenting with intestinal bleeding (p = 0.0002). In Crohn's disease, the lowest level of factor XIIIA was observed in patients with intestinal bleeding (p = 0.0003). Factor XIIIA was correlated with the Van Hees index (r = -0.5661; p = 0.0001) and with the C-terminal telopeptide of type I collagen (r = -0.4110; p = 0.0011) but not with prothrombin fragment 1 + 2. The multiple regression analysis showed that only Van Hees index and intestinal bleeding were independent variables for explaining the diminution of Factor XIIIA in Crohn's disease.

CONCLUSIONS

Factor XIIIA subunit is an indicator of Crohn's disease activity. Our study suggests that a low factor XIIIA level is related to the presence of intestinal lesions and might be linked to intestinal repair mechanisms; loss in intestinal lumen could be also involved, especially in patients with intestinal bleeding.

Possible involvement of Von Willebrand factor in pancreatic graft thrombosis after kidney-pancreas transplantation: a retrospective study

Early postoperative graft thrombosis remains the second cause of failure in pancreas transplantation. Thus, the aim of this study was to compare retrospectively coagulation and fibrinolysis in type I diabetic recipients of simultaneous kidney pancreas transplants having or not experienced thrombosis of their pancreatic graft. From December 1990 to August 1996, 30 simultaneous kidney pancreas transplants were performed in 30 uremic type I diabetic patients. Acute thrombosis of the pancreatic graft was observed among 6 patients (group A), whereas 24 did not develop thrombosis (group B) although 4 died from other causes. The control groups were composed of kidney transplant (group C) or haemodialysed (group D) non-diabetic patients, type I diabetics with HbA1C < 8% (group E) or > or = 8% (group F) who were not in end-stage renal failure and kidney transplant type I diabetic patients (group G). Beginning at least 6 months after transplantation, we analysed hemostatic factors (fibrinogen, thrombin, and prothrombin times), coagulation inhibitors (proteins C and S), fibrinolysis (plasminogen activator inhibitor) and endothelial cell abnormalities (Von Willebrand factor: VWf). Micro and macrovascular complications were evaluated on a score ranging from 0 to 12. Hemostatic factors, coagulation inhibitors and fibrinolysis were similar in groups A and B whereas VWf differed significantly in group A (3.49 +/- 0.93 IU/ml) as compared to group B (2.04 +/- 0.92 IU/ml) (p < 0.05). VWf was also significantly increased in group A relative to the control groups C, D, E, F, and G. The score of vascular complications was increased in groups A and B and significantly higher in group A (9 +/- 0.81 vs. 6.07 +/- 1.75) (p < 0.01), while a correlation (r = 0.812, p > 0.05) was observed between VWf levels and the severity of vascular complications. These results point out the possible involvement of VWf in the pathogenesis of pancreatic vein thrombosis in kidney-pancreas transplantation.

[Acrosyndromes induced by bleomycin in HIV 1 related Kaposi's disease. 5 cases]

OBJECTIVES

Raynaud's syndromes may be observed in HIV-infected patients, particularly those with Kaposi disease treated with bleomycin. This complication occurs in 10% of patients given bleomycin although only 7 cases have been reported in the literature. The aim of this study was to determine the frequency of certain biological abnormalities observed in HIV patients with Kaposi disease given bleomycin and who develop Raynaud's syndromes.

PATIENTS AND METHODS

A survey was conducted from 1989 to 1995 among 1074 patients infected with HIV-1. There were 121 patients with Kaposi disease and 73 of these were treated with bleomycin. The clinical features and laboratory results (cryoglobulinemia, free protein-S, protein-C, anticardiolipin antibodies, von Wille-brand factor (vWF.ag) endothelin-1) were obtained in 5 patients who developed biomycin-induced Raynaud's syndrome.

RESULTS

Amont the 73 patients with Kaposi disease treated with bleomycin (total mean dose = 227 mg (120-380 mg)), 5 patients (12.6%) developed a severe Raynaud's synchrome including two who suffered digital necrosis Withdrawal of bleomycin led to improved symptomatology (n = 2) or an aggravation (n = 1) in the 3 patients followed.

CONCLUSION

Raynaud's syndromes are frequent (12.6%) in HIV patients with Kaposi disease treated with bleomycin. The vascular toxicity of bleomycin, demonstrated in animals, would appear to be the causal factor among others. Release of endothelial factors (vWF.ag endothelin-1) and perturbed hemostasis related to the HIV infection (protein-S deficiency, anti-cardiolipin antibodies) could be an expression of and aggravate the vascular toxicity of bleomycin.

The treatment of deep vein thrombosis with continuous intravenous low-molecular-weight dermatan sulphate (Desmin). A pilot study

Eight patients with femoro-popliteal or sural DVT, confirmed by phlebography, were treated with intravenous Desmin (LMW-dermatan sulphate): on the first day, after an initial i.v. injection of 400 mg, all patients received an infusion of 800 mg in 500 ml of saline, during 24 hours; this infusion was repeated in each of the subsequent 9 days (global treatment period: 10 days). To monitor efficacy of the antithrombotic treatment a phlebography, with calculation of Marder score, was repeated at the end of treatment. Laboratory tests monitoring blood coagulation were carried out: aPTT, TT, PT. Factor Xa inhibition (by chronometric and chromogenic method), Stachrom DS, fibrinogen, prothrombin fragments F1 + 2 and TAT. Seven patients completed the ten-day treatment: 6 patients evidenced good improvement of the phlebographic patterns, 1 remained stationary and 1 patient was withdrawn due to adverse events. During the ten days treatment we did not observe any variation of blood coagulation tests. Desmin tolerability was good and no haemorrhagic episodes were registered. The collected results point to a good antithrombotic activity of the new LMW-dermatan sulphate, that deserves to be further evaluated with controlled investigations on larger number of patients.

Artifact of blood pressure recording using heparin-filled catheter: effects on blood pressure and coagulation parameters

A usual complication of catheterization procedures of arteries for blood pressure recording is the clogging of catheters due to activation of coagulation. This is usually avoided by filling the catheters with a heparinized saline solution. We have studied rats implanted with four catheters, one of which was used to monitor blood pressure for 6 h. Catheters were filled with 100 IU/ml heparin in saline. Using this standard protocol, approximately 50-200 IU of heparin were injected into the animals. This induces significant anticoagulation. The activated partial thromboplastin time (APTT) increased from 27 s to more than 240 s. We devised a modified "low heparin" protocol, in which the concentration of heparin in the wash solution of the catheters was lowered from 100 to 0.1 IU/ml, and the pressor transducer was back-perfused with saline solution without heparin. Using this new protocol, no significant modification of the APTT was observed, indicating that only trace amounts of heparin were injected. Subsequent controlled administration of heparin induced a significant decrease in blood pressure. To avoid all effects associated with this unwanted infusion of heparin, mainly a decrease in blood pressure and a major anticoagulant effect, we suggest the use of such "low heparin" catheterization protocol.

Prothrombin fragment 1 + 2 and thrombin-antithrombin III complex as markers of activation of blood coagulation in inflammatory bowel diseases

OBJECTIVES AND METHODS

The aims of the present work were to assess the presence of thrombin generation in Crohn's disease and in ulcerative colitis by using the prothrombin fragment 1 + 2 and the thrombin-antithrombin III complex assays and to study the possible relationships between these markers and disease activity.

RESULTS

Prothrombin fragment 1 + 2 and thrombin-antithrombin III complex were significantly raised in patients with Crohn's disease (n = 69) and with ulcerative colitis (n = 25) as compared with healthy controls (n = 50). In Crohn's disease these two markers of thrombin generation were correlated with the Van Hees index (P < 0.05 and P < 0.001, respectively); values were significantly different from controls even in the patient group displaying the lowest disease activity (P < 0.001). No correlation was found with tumour necrosis factor alpha and C-reactive protein; nevertheless patients with C-reactive protein less than or equal to 10 mg/l had significant lower values of prothrombin fragment 1 + 2 (P < 0.03). In ulcerative colitis prothrombin fragment 1 + 2 and thrombin-antithrombin III complex were significantly increased by comparison with controls, were higher in patients with pancolitis and correlated with C-reactive protein (P < 0.002 and P < 0.009, respectively).

CONCLUSION

These data show that prothrombin fragment 1 + 2 and thrombin-antithrombin III complex are increased in inflammatory bowel diseases and suggest that thrombin generation might be an early event in their pathogenesis.

Thrombin does not alter vascular hyporeactivity in models of endotoxin-induced septic shock in rats

1. Hypotension and vascular hyporesponsiveness to vasoconstrictors are observed during endotoxic shock, and are associated with increased production of nitric oxide in the vascular wall. Disseminated intravascular coagulation is another feature of septicaemia. We hypothesized that thrombin generated during disseminated intravascular coagulation might modulate the changes in vascular tone induced by endotoxin. 2. Incubation of rat aortic rings for 4 h with alpha-thrombin (0.003-3.0 NIH units/ml) did not change their reactivity to noradrenaline. Incubation for 4 h with lipopolysaccharide increased the EC50 for noradrenaline, whereas co-incubation of thrombin (0.5 NIH units/ml) with lipopolysaccharide did not alter this hyporeactivity to noradrenaline. 3. In vivo in rats, lipopolysaccharide caused early (1 h) and late (4-6 h) hyporeactivity to noradrenaline. In rats infused with lipopolysaccharide and heparin (1 U min-1 kg-1, 0.4 ml/h) or hirudin (2.2 mg ml-1 kg-1, 0.8 ml/h), vasopressor responses to noradrenaline were not different from those after infusion of lipopolysaccharide alone. Aortic rings taken from rats receiving both anticoagulant treatment and lipopolysaccharide had the same sensitivity to noradrenaline as those obtained from rats receiving lipopolysaccharide alone. 4. Our results suggest that, in vivo, disseminated intravascular coagulation does not modify the early and late effects of lipopolysaccharide on arterial pressure and that, in vitro, thrombin neither induces hyporeactivity to noradrenaline nor modifies lipopolysaccharide-induced hyporeactivity. We propose that thrombin generated during disseminated intravascular coagulation in rats does not play a major role in the alterations of vascular tone observed during endotoxic shock.