Changes in haemostasis after laparoscopic surgery in gynaecology: contribution of the thrombin generation test.

Surgery induces immediate hypercoagulability by direct alteration of the vascular bed, release of procoagulant substances from the extravascular spaces and blood flow decrease, and delayed hypercoagulation in response to tissue damage which triggers inflammatory responses. Thus, the postoperative period represents a high-risk time for thrombosis. Recognition of high-risk individuals would make it possible to improve thromboembolism prevention. We studied in women undergoing laparoscopic surgery a series of markers known to be related to the thrombotic risk and confronted their results with those of a global test, the thrombin generation test (TGT) described by Hemker's group. Our results show that two groups of patients can be distinguished according to usual risk markers (PAI-1, TAT, body mass index): the higher risk group demonstrates higher initial TGT values, but also a postoperative decrease of the TGT values whose mechanisms remain to be defined.

Sensitization decreases relaxation in human isolated airways.

Passively sensitized human isolated airways provide an opportunity to study some aspects of bronchial hyperresponsiveness in vitro. Since it has been suggested that excessive airway narrowing could be due to impaired relaxation, we examined the effect of a variety of agents producing relaxation via different mechanisms, i.e., verapamil and lemakalim (a calcium channel antagonist and a potassium channel opener, respectively) and isoproterenol, forskolin, and dibutyryl cAMP (modulators of the beta-adrenoceptor signal transduction pathway). Human bronchial rings, obtained at thoracotomy, were passively sensitized by incubation in serum from atopic asthmatic patients, and control rings were incubated in serum from nonatopic subjects. We also studied bronchial rings from five spontaneously sensitized human lung specimens. Responses to the relaxant compounds were measured isometrically. Passive sensitization significantly decreased the efficacy of verapamil in maximally contracted tissues from 60 +/- 10 to 45 +/- 7% of the maximal carbachol response (n = 6, p < 0.05) and that of lemakalim from 51 +/- 16 to 38 +/- 14% (n = 7, p < 0.05) in tissues at baseline tone. Similarly, spontaneously sensitized tissues relaxed less to lemakalim (64 +/- 6% of the maximal response to isoproterenol, n = 5, p < 0.05) than did nonsensitized tissues (80 +/- 4%). Sensitization did not alter responses to isoproterenol, forskolin, and dibutyryl cAMP. We conclude that sensitization of human isolated airways reduces relaxation responses that depend upon activation of ion channels but not those that depend upon activation of beta-adrenoceptors and transduction processes directly coupled to these receptors.