A high titer of acquired factor V inhibitor in a hemodialysis patient who developed arterial thrombosis.

An 87-year-old man with diabetes mellitus was admitted to control recurrent bleeding from hemodialysis puncture sites. He was a smoker and had been diagnosed with arteriosclerosis obliterans. His PT and APTT were markedly prolonged, and all coagulation factors were markedly decreased (factor V [FV] activity < 1%) or below the measurement threshold, with the exception of fibrinogen and factor XIII. Neither PT nor APTT were corrected upon mixing with normal plasma. A high titer of FV inhibitor was found at 415 BU/mL, and anti-FV autoantibody was detected by both immunoblot assay and ELISA. Prednisolone administration and plasma exchange partially improved prolonged PT and APTT and decreased the FV inhibitor level. Five months later, he manifested symptoms of severe ischemia in both legs. Angiography revealed diffuse stenosis downstream of both common iliac arteries. Endovascular therapy was repeated four times, the prednisolone dose was reduced, and low-dose antiplatelet therapy was initiated. After the final successful endovascular therapy, arterial thrombosis was detected using ultrasound and angiography. Aspiration thrombectomy and thrombolytic therapy failed to achieve recanalization, and necrosis of the legs worsened. Despite the severe coagulation abnormalities, vascular interventions should have been performed with regular-dose antiplatelet therapy, as the patient exhibited multiple risk factors for atherothrombosis.

Lipopolysaccharide transport system across colonic epithelial cells in normal and infective rat.

To clarify whether lipopolysaccharide (LPS) is transported in rat intestinal epithelial cells, the transport of FITC-LPS across colonic epithelial cells in normal and LPS-exposured rats using a diffusion chamber was examined. The expression of CD14 and Toll-like receptor 4 (TLR4) was also examined. Rats were given 10 mg/kg LPS i.p. injection at 4 hr prior to the isolation of colonic epithelial tissues. The permeation rate across colonic mucosa by FITC-LPS was several times greater in the mucosal to serosal (M to S) direction than in the opposite direction in both normal and LPS-exposured rats. Increased M to S permeation by FITC-LPS was evident at 37 degrees C, but not at 4 degrees C. The permeability of FITC-LPS in both the M to S and S to M directions was inhibited by unlabeled LPS, anti-CD14 antibody or anti-TRL4 antibody in normal rat. In LPS-exposured rat, the inhibition in the M to S direction was observed by anti-TLR4 antibody, but not by unlabeled LPS and anti- CD14 antibody. In contrast, the permeability in the S to M direction was decreased only by unlabeled LPS in LPS-exposured rat. In normal rat, the expression of CD14 and TLR4 was found in the mucosal and serosal sides. In LPS-exposured rat, the expression of CD14 was not observed in the mucosal side. The electrophysiological parameters by LPS exposure remain unchanged. These findings suggest the possibility that colonic epithelial cells contain specific transport systems for LPS, one of which shows some degree of substrate specificity with the interaction of CD14 and/or that of TLR4.

Comparative study of flux of FITC-labeled Dextran 4000 on normal (iso)- and hyper-osmolarity in basal side in caco-2 cell monolayers.

We have shown previously that the flux of fluorescein isothiocyanate dextran 4000 (FD-4) is transported across the Caco-2 cell monolayers in a polarized fashion favoring the basal to apical direction under normal conditions (i.e., isotonic solution in basal side). Furthermore, FD-4 transport may occur via a process that included a certain degree of substrate specificity for polysaccharide and transcytosis. In the present study, we compared the flux of FD-4 in the basal to apical direction (efflux) and the apical to basal direction (influx) in stress conditions (i.e., hyperosmolarity in basal side) to those in normal conditions (i.e., iso-osmolarity in basal side). The efflux of FD-4 was increased by hyperosmolarity in basal side, but the influx was decreased when compared with normal conditions. Neither dextran 10, 000 nor colchicine inhibited the efflux of FD-4 in hyperosmolarity conditions. The inhibition of efflux of FD-4 was observed not by S-nitroso-N-acetylpenicillamine but by sodium nitroprusside and sodium ferrocyanide. These results collectively suggest that hyperosmolarity in basal side accelerates the efflux of FD-4 across the transcellular route but not across the paracellular route in Caco-2 cell monolayers. And it is indicated that cyanide rather than nitric oxide is involved in dysfunction of the FD-4 efflux system irrespective of conditions such as normal osmolarity or hyperosmolarity.