Contribution of intercellular adhesion molecule 1 (ICAM-1) to the pathogenesis of splanchnic artery occlusion shock in the rat.

1. It has been suggested that leukocytes play a key role in the pathogenesis of splanchnic artery occlusion shock. Intercellular adhesion molecule 1 (ICAM-1) is an adhesion molecule of crucial importance in the phenomenon of leukocyte accumulation. 2. We investigated the involvement of ICAM-1 in the pathogenesis of splanchnic artery occlusion shock. Splanchnic artery occlusion (SAO) shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham-operated animals were used as controls. Survival time, serum tumour necrosis factor-alpha (TNF-alpha), white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase activity (MPO; studied as a quantitative means to assess leukocyte accumulation) and the responsiveness to acetylcholine of aortic rings were investigated. SAO shocked rats had a decreased survival time (90 +/- 9.5 min, while sham-shocked rats survived more than 4 h), reduced mean arterial blood pressure, increased serum levels of TNF-alpha (201 +/- 10 mu ml-1) and MPO activity in the ileum (0.15 +/- 0.03 mu x 10(-3) per g tissue) and in the lung (1.9 +/- 0.8 mu x 10(-3) per g tissue), leukopenia and reduced responsiveness to acetylcholine (ACh, 10 nM-10 microM) of aortic rings. 3. Administration of monoclonal antibody raised against rat ICAM-1 significantly increased survival time (225 +/- 9 min), reduced leukopenia and MPO activity both in the ileum (0.031 +/- 0.003 mu x 10(-3) per g tissue) and in the lung 0.23 +/- 0.03 mu x 10(-3) per g tissue), improved the cardiovascular changes and restored the responsiveness to ACh of aortic rings. 4. Our findings are consistent with an involvement of adhesion mechanisms in vivo in the pathogenesis of SAO shock and suggest that specific adhesion mechanisms, which support leukocyte accumulation,may represent potentially important therapeutic targets in circulatory shock.

Protective effects of G 619, a dual thromboxane synthase inhibitor and thromboxane A2 receptor antagonist, in splanchnic artery occlusion shock.

Splanchnic artery occlusion (SAO) shock was induced in anesthetized rats by clamping the celiac trunk and the superior mesenteric artery for 45 min. The arteries were then released and survival rate, mean survival time, mean arterial blood pressure (MAP), plasma levels of thromboxane B2 (TxB2) and 6-keto-PGF1 alpha, and the phagocytotic activity of peritoneal macrophages were evaluated. Shocked animals died within 89 +/- 10 min, while all sham-shocked rats survived greater than 3 h. SAO shock produced relevant changes in MAP, significantly increased plasma levels of TxB2 and 6-keto-PFG1 alpha, and decreased peritoneal macrophage phagocytotic activity. The administration of G 619, a dual thromboxane synthase inhibitor/thromboxane A2 receptor antagonist (50 mg/kg, 15 min before SAO shock) significantly increased survival time (190 +/- 13 min) and survival rate, reduced plasma levels of TxB2, and partially restored the impairment in peritoneal macrophage phagocytosis. Finally, the administration of G 619 had beneficial effects on changes in MAP-induced bay SAO shock. These data further confirm the involvement of TxA2 in SAO shock and suggest that G 619 may have positive effects in low-flow states.

No effect of thioridazine on plasma concentrations of carbamazepine and its active metabolite carbamazepine-10,11-epoxide.

The effect of an oral treatment with thioridazine (100 or 200 mg daily) on plasma concentrations of carbamazepine (CBZ) and its active metabolite carbamazepine-10,11-epoxide (CBZ-E) was studied in eight epileptic patients stabilized on CBZ therapy. No significant changes in steady-state plasma levels of CBZ and CBZ-E occurred, suggesting that CBZ metabolism is not apparently affected by thioridazine.