[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.

Large scale isolation of human blood monocytes by continuous flow centrifugation leukapheresis and counterflow centrifugation elutriation for adoptive cellular immunotherapy in cancer patients

The increasing interest in mononuclear phagocytes for adoptive cellular immunotherapy (ACI) trials in cancer patients led us to define a procedural approach to harvest reproducibly highly purified single-cell suspensions of large numbers of functional human circulating blood monocytes (Mo). A semiclosed counterflow centrifugal elutriation (CCE) system has been developed, using a new large capacity Beckman JE 5.0 rotor with one interchangeable 40 ml or 5 ml separation chamber, to purify Mo from mononuclear cell (MNC) concentrates of healthy donors and cancer patients obtained by continuous flow centrifugation leukapheresis (CFCL). This method does not require a Ficoll density gradient centrifugation step. A total of 115 leukapheresis procedures were carried out in 35 patients and in 30 healthy donors by either Cobe 2997 or Cobe Spectra, with a similar efficiency in MNC apheresis. The average yield per leukapheresis procedure was 5.6 x 10(9) MNC of purity 90-100% (25-45% Mo, 40-65% lymphocytes). The average yields per elutriation procedure (R/O fraction) were 1.1 x 10(9) cells (purity 93% Mo) using the 5 ml separation chamber, and 1.5 x 10(9) cells (purity 91%) using the 40 ml separation chamber, with a respective recovery of 82 +/- 7% and 78 +/- 8% Mo. In vitro analysis of the viability and function of the purified Mo shows that neither morphological integrity nor physiological activity was compromised by this two-step isolation procedure, which additionally provides highly purified human Mo suspensions, in a quantity suitable for ACl of cancer patients.

Prevalence and significance of anticardiolipin antibodies in Crohn's disease

Crohn's disease is a chronic inflammatory bowel syndrome in which thrombotic complications occur in the active phase. Phospholipid-binding antibodies such as anticardiolipin antibodies and lupus anticoagulants have been shown to be associated with thrombosis. Their presence has been assessed in a group of 50 patients with Crohn's disease among whom 44 had active disease. The overall prevalence of anticardiolipin antibodies was about 22%, while none of these patients had lupus anticoagulant. Anticardiolipin antibodies have been observed in both active and quiescent CD and their presence does not seem to be related to the site of CD lesions. The presence of phospholipid-binding antibodies could be a sign of vascular alterations that are potentially thrombogenic per se, and their predictive value with respect to the specific inflammatory syndrome of Crohn's disease is discussed.

Variation in von Willebrand's Factor according to the treatment of acute myocardial infarction: physiopathological and clinical implications

To investigate whether von Willebrand's Factor (vWF) changes as a result of the reperfusion strategy during acute myocardial infarction (AMI), vWF was measured on days 0, 1, 2, 3, 4, 5 and 15 in 34 patients with AMI. Thrombolysis was initiated in 22 patients and followed by a coronary angiogram 90 min later. In 13 patients the infarct-related artery was then patent (THR group). In nine patients the infarct-related artery was occluded and rescue percutaneous transluminal coronary angioplasty was performed (group THR+rPTCA). In 12 patients, primary PTCA was carried out (pPTCA group). Admission values of vWF were similarly high in the three groups, while changes in vWF over the following days were statistically different among the groups. No significant change was observed in THR, whereas a significant and prolonged increase was found after failed thrombolysis with PTCA (peak increase at day 5:1.54 +/- 0.04 U.ml-1). In the pPTCA group, a significant increase could only be found on day 3 (0.96 +/- 0.04 U.ml-1). Absence of a statistical rise in vWF might be a late indicator of successful thrombolysis. The prolonged increase in vWF after failed thrombolysis needing rescue PTCA probably reflects a higher resistance to thrombolysis, while the slight but significant increase in vWF following primary PTCA could be due to vascular injury.

[Von Willebrand factor in coronary disease]

The value of studying factors of haemostasis and thrombosis in patients with coronary artery disease is established. The endothelial lesion and evolution of the thrombus play key roles in acute coronary syndromes and coronary angioplasty. The von Willebrand factor (VWF) is known for its participation in primary haemostasis. Deficits of this factor lead to a haemorrhagic syndrome, von Willebrand's disease. This glycoprotein is mainly synthesised by the endothelial cells. Its polymeric composition allows identification of two types of multimeres. The high molecular weight, active multimeres are liberated from the endothelium after stimulation by thrombin. Low molecular weight multimeres are less active and are secreted continuously. The VWF promotes platelet adhesion and facilitates platelet aggregation. Experimental pig models with VWF deficiency show that this factor is essential for the constitution of an occlusive thrombus. Several physiopathological mechanisms interact to increase VWF concentrations during thrombosis: the endothelial lesion, adrenergic stimulation, acute phase reaction. Increased VWF concentrations have been reported in many clinical situations. The results are most demonstrative in coronary artery disease. The VWF is abnormally high from the time of hospital admission in patients with acute myocardial infarction and continues to increase up to the 5th day before falling, without returning to normal values, at the 15th day. It is a sensitive though not specific late diagnostic marker of myocardial infarction. Increased VWF concentrations are not proportional to the severity of coronary atherosclerosis. They are, however, related to the infarct size, to the inflammatory reaction and to the prothrombotic phase.(ABSTRACT TRUNCATED AT 250 WORDS)

[Gray platelet syndrome]

BACKGROUND

Gray platelet syndrome is a rare (about 40 cases published), inherited disorder characterized by a marked decrease or absence of platelet alpha-granules and platelet specific alpha-granule proteins.

CASE REPORT

A boy, aged 4 years, presented with frequent ecchymoses. Acute idiopathic thrombocytopenia purpura was diagnosed because of his reduced platelet count (36,000/mm3) and recent viral infection. Intravenous gammaglobulin infusion was followed by a small rise in the platelet count (125,000/mm3). The patient was reinvestigated a few months later because of persistent thrombocytopenia and the failure of the immunologic treatment. The bleeding time was long and the platelets on blood smears appeared gray. Electron microscopy revealed numerous vacuoles and very few or no alpha-granules. Platelet aggregation and adhesion were normal, but stimulated platelets failed to liberate factor 4 and beta-thromboglobulin, while the plasma levels of beta-thromboglobulin were elevated.

CONCLUSION

The frequency of gray platelet syndrome is probably underestimated in those diseases resulting in thrombocytopenia and this will continue until blood smears are thoroughly examined. Synthesis of platelet specific alpha-granule proteins seems normal; but these proteins cannot be stored as there are very few, or no alpha-granules. This abnormality could lead to increased levels of such proteins in the plasma.

Hemostatic changes in human adoptive immunotherapy with activated blood monocytes or derived macrophages

Human blood monocytes (Mo) and monocyte-derived macrophages (M psi) possess cytotoxic effects against tumor cell lines when appropriately stimulated by various biological response modifiers, e.g., gamma interferon (gamma IFN) and muramyltripeptide (MTP). Activated Mo/M psi represent a new tool for the treatment of human malignancies, termed "adoptive cellular immunotherapy". Activated Mo/M psi express tissue factor procoagulant activity (PCA), which is a physiological trigger of blood coagulation. PCA was evaluated in vitro using a modification of the one-stage recalcification clotting time, and hemostatic changes were studied in vivo in cancer patients. Nine patients with peritoneal carcinomatosis were injected intraperitoneally with activated Mo and 11 patients with non-small cell lung carcinomas were infused intravenously with activated M psi. Hemostatic changes were followed using activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen level, antithrombin III (ATIII) and protein C (PC) activities. Fibrinolytic activity was estimated by euglobulin lysis time and assays for plasminogen and fibrin/fibrinogen degradation products (FDP). These assays were performed before and after each autologous infusion and on days 2 and 3. Activated Mo and M psi expressed potent PCA (85.5 +/- 7.5 U/ml for MTP activated Mo and 50 +/- 5.3 U/ml for gamma IFN activated M psi suspensions). In both groups of patients, APTT, PT, and TT underwent no significant variations. There was no significant consumption of ATIII or PC, and fibrinolysis was not activated during the study period. In the group injected intraperitoneally with MTP-activated Mo, fibrinogen showed a significant and progressive increase in relation to the development of an inflammatory reaction, reaching a maximum average value of 6.1 g/l at the end of the therapy with a concomitant increase in FDP levels. This increase was not observed after intravenous therapy with gamma IFN-activated M psi. No patient suffered from hemorrhagic or thrombotic events. In our experience, repeated injections of activated Mo or M psi expressing potent tissue factor PCA did not induce significant in vivo activation of the coagulation system in cancer patients.

[Antiphospholipid antibodies (aPL): detection and clinical significance]

Phospholipid-binding antibodies are heterogeneous immunoglobulins of G and/or M and/or A class which can be detected in association with a variety of pathologies. However they can also occur in the absence of any clinical manifestations. Despite their paradoxical in vitro anticoagulant activity, phospholipid-binding antibodies, either primary or secondary, are frequently associated with venous and/or arterial thrombotic events. Hence, their detection has to be performed in several major clinical situations, cerebral attack, myocardial infarction, recurrent fetal loss, deep vein thrombosis ... Their course has to be controlled at least every six months. Since the incidence of phospholipid-binding antibodies in auto-immune pathologies is high, immunological disorders should also be considered. As yet there is no standardized assay of phospholipid-binding antibodies, either functional with respect to their anticoagulant activity, or immunological (ELISA). It is not established whether they possess an own pathogenic potential or appear as a secondary response following cellular alterations known to be thrombogenic. However it has been suggested that they could participate in the disruption of the hemostatic balance towards procoagulant tendency resulting in thrombosis.

Electrophoretic studies on molecular defects of von Willebrand factor and platelet glycoprotein IIb-IIIa with antibodies produced in egg yolk from laying hens

Immunoglobulins isolated from egg yolk (IgYs) are a convenient source of polyclonal antibodies. Their purification is simple and the yields important (50 mg immunoglobulins/egg). Nevertheless their biochemical characteristics are different from those of rabbit antibodies generally used for the study of molecular defects of plasmatic and platelet proteins. Provided standardization is achieved, IgYs can be used for immunoelectrophoresis, immunoprecipitation or immunoblotting assays. We describe here the electrophoretic and immunoblotting conditions employed to explore human plasmatic and platelet von Willebrand factor (vWF) and human platelet GP IIb-IIIa using IgYs. These two proteins are involved in primary hemostasis and their absence or abnormality is responsible for hereditary bleeding disorders. The methods were applied to the characterization of patients with vWF or GP IIb-IIIa defects and compared to classical mammalian IgG immunoelectrophoretic techniques. Results were further confirmed by flow cytometric analysis.

The catalytic role of anionic phospholipids in the activation of protein C by factor Xa and expression of its anticoagulant function in human plasma

Phospholipids bearing a proportion of anionic species such as phosphatidylserine are necessary to promote the anticoagulant potential of the protein C pathway. Factor Xa (200 or 350 pM) was found to activate protein C in a thrombomodulin-independent reaction requiring only phospholipids in Al(OH)3,-adsorbed plasma resupplemented with physiological concentrations of protein C (70 nM) and protein S (130 nM). All experiments were performed in the presence of an excess of hirudin. The activity of activated protein C was assessed by the survival of factor Va. The optimal phospholipid concentration range was 5 to 25 microM with a proportion of phosphatidylserine of 50% (mol/mol) resulting in a half-life of factor Va of 7.5 min in the absence of protein S and 4.2 min in its presence. Dns-EGR-Xa, an inactive derivative of factor Xa, behaved as an apparent protector of factor Va. When replacing factor Xa, thrombin at 10 nM was not an efficient protein C activator in the absence of purified human placenta thrombomodulin. In the presence of 100 pM activated protein C, factor Va half-life was 2 min in the absence of protein S and 1.1 min in its presence in the above optimal phospholipid concentration range. The presence of protein S allowed reduction of phospholipid requirements. Annexin-V (placental anticoagulant protein-I), a potent phospholipid antagonist, fully protected factor Va from degradation by phospholipid-dependent mechanisms. Factor Va was partially protected in the plasma of a patient having experienced thrombosis associated with lupus-like anticoagulant and anti-phospholipid auto-antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Phase I study of liposomal MTP-PE-activated autologous monocytes administered intraperitoneally to patients with peritoneal carcinomatosis

We have conducted a phase I study with autologous monocytes activated ex vivo and administered intraperitoneally in nine patients with peritoneal carcinomatosis. Blood monocytes were collected by leukapheresis and then purified by counterflow elutriation (up to 10(9) cells, with a purity of greater than 90%). Ex vivo activation was obtained by incubating these cells with 1 micrograms liposomal MTP-PE/10(6) monocytes for 18 hours in hydrophobic culture bags at 37 degrees C in 5% carbon dioxide humidified air. The activated monocytes were then infused in the peritoneal cavity once a week for 5 consecutive weeks through an implanted peritoneal infusion system, Port-A-Cath (Pharmacia Deltec, St Paul, MN), on an intrapatient dose-escalating schedule (10(7) to 10(9) monocytes). No severe adverse reactions occurred. Toxicity was mild, the chief acute reactions being fever (27%), chills (13%), and abdominal pain (25%). None of the side effects led to dose reduction. No consistent change in hemostatic function, liver function, or renal function was observed. Significant increases in granulocyte counts, neopterine, and acute phase reactants (fibrinogen, C-reactive protein) occurred in the peripheral blood. In vitro monocyte activation was demonstrated by the relapse of procoagulant activity and monokines (interleukin-1 [IL-1], IL-6, and tumor necrosis factor-alpha [TNF alpha]) in the supernatants of cultured monocytes. Evidence for in vivo monocyte activation was provided by the increase of these monokines in the peritoneal fluids. Kinetic studies with indium-111 (111In)-labeled activated autologous monocytes in five patients suggest that these infused monocytes may remain in the peritoneal cavity for up to 7 days. This locoregional immunotherapeutic approach seems to be encouraging in view of adjuvant therapeutic modality in ovarian cancer patients with minimal residual intraabdominal disease following second-look laparotomy.

Novel point mutations leading to type 1 antithrombin deficiency and thrombosis

Direct sequencing of antithrombin III (AT) gene fragments specifically amplified by the polymerase chain reaction was utilized to identify the molecular basis of type 1 AT deficiency in two unrelated kindreds, both with thrombotic disease. Two novel point mutations were identified, deletion of a T from the second position of codon 81 in one propositus and insertion of a G in codon 424 in the second kindred. The AT 81(-T) frameshift mutation leads to a premature stop signal in codon 89, while the AT 424(+G) allele has a premature stop only one codon short of the normal gene. The latter mutation changes the eight carboxy terminal residues of AT, including 429Cys, and increases the proportion of polar amino acids in this region. We suggest that altered folding of the mutant protein may explain the AT deficiency.

[Influence of protein S deficiency on the arterial thrombosis risk]

Protein S is the cofactor of activated protein C which, together with the antithrombin system, is a major regulator of coagulation. Congenital protein S deficiency is an important risk factor for venous thrombosis. In this study of 105 patients with protein S deficiency, 64 had one of several thromboembolic accidents, including 14 arterial thrombotic accidents involving the central nervous system or the myocardium. These accidents occurred in young subjects (mean age: 25 +/- 13 years) only one-third of whom had another risk factor. This high frequency of arterial thrombosis associated with protein S deficiency calls for a prospective study in young subject with cerebral vascular accident or myocardial infarction.

Apheresis-elutriation program for adoptive immunotherapy with autologous activated monocytes in cancer patients

Human blood monocytes (Mo) and monocyte-derived macrophages (M phi) are known to be potent antitumor cytotoxic effector cells through activation with recombinant human interferon gamma (rIFN-gamma), bacterial muramyldipeptide or the synthetic derivative muramyltripeptide phosphatidylethanolamine entrapped in liposomes (L-MTP-PE). Large-scale generation of ex vivo activated Mo from the blood of cancer patients proved feasible. We report our experience with a fixed rotor speed counterflow centrifugation elutration (CEE) procedure using the newly available Beckman high capacity JE-5.0 rotor system that reproducibly isolates up to 1.0-1.5 x 10(9) Mo with greater than 90% purity, in suspension and functionally intact derived from peripheral blood mononuclear cell-enriched suspensions obtained by leukapheresis (LP) from healthy volunteers and cancer patients. The semiclosed, easy to handle CCE system, was adapted to a sterile technique that permitted clinical trials in adoptive monocyte immunotherapy. Freshly isolated Mo did not lose morphological or functional integrity and had no spontaneous activation. Their abilities to become activated to the cytotoxic state after 18-h stimulation with 500 U/ml rIFN-gamma or 1 microgram/ml L-MTP-PE and to differentiate into matured M phi in vitro were not altered. The system was therefore used to isolate large numbers of Mo for a phase I clinical trial of intraperitoneal immunotherapy with L-MTP-PE activated autologous Mo in nine patients with peritoneal carcinomatosis. Each patient received weekly Mo infusions (n = 5) with an intrapatient dose escalation schedule (from 10(7) to 10(9) Mo). Toxicities were mild including fever, chills and abdominal pain. There was no treatment-induced thromboembolic event or capillary leak syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA amplification of HIV genome in hemophiliacs and in newborns from seropositive mothers

We evaluated the validity of DNA enzymatic amplification (PCR) in a population at risk for HIV-1 infection, consisting of hemophiliacs and children born to seropositive mothers. All but one of the seropositive hemophiliacs and controls were found positive with the three sets of primers. All the seronegative patients and controls were found negative in PCR. No correlation with the anti-nef serology was found, one seropositive being anti-nef negative and three seronegative anti-nef positive. The results obtained with PCR are in good agreement with classical serology, and this would suggest that the possible period of latency may not be as long as suspected. No seroconversion has been described in hemophiliacs since solvent-detergent inactivated blood products have been in use, and seronegative hemophiliacs no longer constitute a population at risk. Studies on seronegative sexual partners of seropositive patients would be of great interest. For newborns from seropositive mothers, PCR is the only possible technique in early age before seronegativation of the healthy children. Further studies will be required to determine the fiability and sensitivity of the test.

A randomized study of on-line plasma perfusion over protein A-sepharose and 5-fluorouracil chemotherapy in patients with metastatic colorectal carcinoma

To evaluate the safety of on-line plasma perfusion over protein-A sepharose and the therapeutic advantage of combining plasma perfusion (PP) over protein-A sepharose with 5-fluorouracil (5-FU) chemotherapy in patients with metastatic colorectal carcinoma (MCRC), thirty patients were randomized after surgery of primary CRC to receive a combination of 5-FU and PP over protein-A sepharose (group A), or a combination of 5-FU and PP over sepharose (group B), or 5-FU alone (group C). Bi-weekly on-line PP over 200 ml protein-A sepharose gel (group A) or 200 ml sepharose gel (group B) were performed with a Cobe 2997 blood cell separator for a maximum of 19 treatments per patient. 5-FU was given at 1000 mg/m2/d on days 1-5 of a 4-weekly cycle until progression. PP was well tolerated and no severe or life-threatening toxicity was observed. Mild clinical side-effects consisted of fever and chills (36% in group A, 23% in group B). The most common biological effects of PP over protein-A sepharose were significant drops in IgG (66% of pre-PP values), CH50 and C3 (73% of pre-PP values) and a significant generation of C3a and C5a anaphylatoxins. Tumor response rates were 40% for group A, 0% for group B and 20% for group C. The median survival times tended to be longer in group A (17 months) than in group B (10 months) and in group C (9 months). This is the first randomized trial showing some therapeutic advantage in combining PP over protein-A sepharose with conventional chemotherapy in MCRC.

Phase I trial of intravenous infusion of ex-vivo-activated autologous blood-derived macrophages in patients with non-small-cell lung cancer: toxicity and immunomodulatory effects

The purpose of this phase I study was to evaluate the toxicity and biological activity of autologous blood-derived macrophages activated ex-vivo with recombinant human interferon gamma (rhuIFN gamma) [monokine-activated killer (MAK) cells] and administered intravenously to 11 lung cancer patients once a week for 6 consecutive weeks. Peripheral blood monocytes were collected by leukapheresis and then purified by counterflow elutriation. The MAK cells were generated by culturing the purified monocytes in Teflon bags for 7 days and adding rhuIFN gamma to the cultured cells for the last 18 h. These MAK cells expressed differentiation-associated surface antigen MAX1, and were cytotoxic in vitro against tumour cell line U937. The MAK cells were infused at dose levels from 1 x 10(7) to 5 x 10(8) on an intrapatient dose-escalating schedule. No severe adverse side-effects occurred. Toxicity was mild to moderate [primarly fever (75%) and chills (32%)], non-dose-dependent, and non-cumulative. No consistent change in haemostatic function, or liver or renal function was observed. Dose-limiting toxicity was not reached at 5 x 10(8) cells (optimal dose reproduced for each patient). The maximum tolerated dose was not determined. The immunomodulatory activity of i.v. infused MAK cells was demonstrated both in vivo by significant increases in granulocyte count and neopterin level in the patients' peripheral blood post-infusion and in vitro by secretory products (IL-1. TNF alpha, neopterin, and thromboplastin-like substance) in the culture supernatants. The in vivo traffic patterns of autologous MAK cells labelled ex-vivo with 111In oxine were studied in 7 patients. Gamma imaging showed an immediate but transient lung uptake (less than 24 h), and a progressive uptake of radioactivity in the liver and spleen was seen from 6 h to 72 h post-infusion. Our results indicate that the preparation of high numbers of autologous, blood-derived MAK cells is a feasible procedure, and their transfusion is safe for patients. This immunotherapeutic approach seems to be encouraging from the point of view of establishing an adjuvant therapeutic modality in cancer patients with minimal residual disease.

[Congenital deficiencies of natural anticoagulant systems responsible for recurrent thromboembolism]

The main characteristics of the blood coagulation system is its high potential of autoamplification. Cascade reactions consisting of successive activations of zymogens into their respective serine-proteinase active form culminate in the generation of thrombin, the central enzyme of the system. Blood coagulation is under control of two major natural regulatory mechanisms limiting the extension of the thrombus. The first one with antithrombin III as the central element, directly inhibits thrombin and other activated clotting factors in cooperation with heparans synthetized by the vascular wall. The second one, the protein C pathway, limits thrombin generation, through its ability to block the amplification potential of feedback reactions. The physiological significance of these regulatory mechanisms is clearly emphasized by the frequency of recurrent thrombotic episodes affecting subjects presenting an inherited deficiency of one of these components, estimated between 50 and 70%. Patients with protein S deficiency, the essential cofactor of activated protein C, exhibit a surprisingly high tendency to arterial thrombosis. The biological investigation of thromboembolic disease must be focused on antithrombin III, protein C and protein S deficiency using functional assays when available or feasible in order to detect both qualitative and quantitative defects.

Screening of protein S deficiency using a functional assay in patients with venous and arterial thrombosis

Protein S is the vitamin K-dependent cofactor of activated protein C which functions as a potent anticoagulant by degrading activated factors V and VIII in a Ca2+ and phospholipid-dependent reaction. Protein S circulates under two forms, free (approximately 40%) or bound to C4b-binding protein (C4b-bp); only the free form supports the cofactor activity for activated protein C. Total protein S antigen is usually measured by rocket immunoelectrophoresis. Free protein S antigen is measured by the same technique but after precipitation of the protein S-C4b-bp complex by PEG 8000. However, these immunological assays do not detect functional alterations of protein S which can be responsible for thrombosis. This paper describes a functional assay for free protein S based on its ability to promote the prolongation of clotting time following factor Va inactivation by activated protein C when coagulation is triggered by factor Xa. Using this assay a prolongation of about 100 s between 0 and 1 U/ml protein S is measured, allowing a reliable and rapid determination of functional protein S. The correlation coefficient between functional protein S and free antigenic protein S is 0.921. This functional protein S assay has allowed the detection of 34 cases of protein S deficiency, confirmed by immunological assays, and their classification. The striking observation is the high frequency (approximately 25%) of arterial thrombosis in these patients. The rapid determination of functional protein S in patients with venous or arterial thrombosis is of diagnostic interest and should allow the detection of mutant protein S in combination with an immunological assay.

A randomized study of combined 5-fluorouracil and plasma perfusion over protein A-sepharose in human advanced colorectal carcinoma

To evaluate the advantage with regard to toxicity, response rate, time to progression and survival of combination chemoimmunotherapy over single-agent chemotherapy in patients with metastatic colorectal carcinoma (CRC), 30 patients were randomized to receive a combination of 5-fluorouracil (5-FU) by continuous i.v. infusion and plasma perfusion (PP) over protein A-Sepharose (group A), or a combination of 5-FU and PP over sepharose (group B) or 5-FU alone (group C). 5-FU was given at 1,000 mg/m2/d on days 1-5 of a 4-weekly cycle until progression. Patients of groups A and B received bi-weekly on-line PPs until disease progression or for a maximum of 19 treatments. PP was well tolerated and no severe or life-threatening toxicity was observed. The response rates were 10% for the group A (1 PR), 0% for the group B and 20% for the group C (1 CR + 1 PR). The times to tumor progression for patients in groups A and C were 22 months, 12 and 11 months, respectively and the median survival times were 17 months, 10 months and 9 months. Although the time to progression and survival tended to be higher in patients treated with protein A. PP, these differences were not statistically significant. This is the first report of a randomized trial showing some therapeutic advantage in combining protein A. PP with 5-FU in CRC patients. Further randomized studies are required to demonstrate the real true value of this chemoimmunotherapeutic approach.

[Relation of an increase of von Willebrand factor in the blood, acute myocardial infarction, unstable angina and coronary thrombosis]

Forty six patients admitted for precordial chest pain were included in this study. The clinical, electrocardiographic, enzymatic and angiographic features allowed retrospective identification of 6 subgroups (nos 1 to 6): all transmural myocardial infarction (Q-MI) (Group 1), Q-MI without intracoronary thrombus (Group 2), Q-MI with intracoronary thrombus (Group 3), acute non-Q wave infarction (non Q-MI) (Group 4), unstable angina (Group 5) and atypical chest pain (Group 6). Several blood clotting factors were studied; von Willebrand factor (VWF), fibrinogen, tissue plasminogen activator (t-PA) and its inhibitor (PAI-1) and factor VII. There was no significant difference in the fibrinogen, t-PA, PAI-1 or factor VII levels between the 6 groups. On the other hand, the VWF was increased in the all transmural myocardial infarction (Q-MI) groups (n. 1). In Group 3 with visible intracoronary thrombus the VWF was high or very high in all patients, attaining three times the normal values. The values were lower in Group 5 (unstable angina) patients in whom no thrombus was observed on coronary angiography. The differences between Group 1 and Groups 4, 5 and 6 were statistically significant (p less than 0.05). The VWF was higher in the Q-MI group with intracoronary thrombus than in the group without thrombus, but the difference was not statistically different. In conclusion, the VWF may be considered to be a marker for thrombus and/or endothelial activation but a larger study population would be required to identify more accurately the subgroups with thrombosis or risk of thrombosis.