We previously reported that the plasma level of NOX, metabolites of nitric oxide, was markedly increased, but that of endothelin was slightly increased in the tissue factor(TF)-induced DIC model in rats, while both of them were markedly increased in the lipopolysac-charide(LPS)-induced DIC model. In this study, we investigated the effect of low molecular weight heparin (LMWH) on these vasoactive substances in both types of DIC models. For the introduction of DIC in the Wistar strain rats, either 30 mg/kg of LPS or 3.75 units/kg of TF was given to the animals via the tail vein over a period of 4 hours. To see the effect of LMWH, administration of 200 units/kg of LMWH was started 30 minutes prior to the administration of TF or LPS, and continued with TF or LPS for another 4 hours. In the TF-induced model, suppression by LMWH of the increase of NOX in plasma was nearly complete, while it was only slight in the LPS-induced model. On the other hand, plasma level of endothelin was not affected by LMWH in both TF-induced and LPS-induced models. It is thus suggested that increase of NOX in plasma in the TF-induced model is not due to the direct effect of TF but rather due to activation of the hemostatic system. On the other hand, persistently elevated plasma endothelin in the LPS-induced model may be attributed to the organ dysfunction in the animals.

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A boy of two years and seven months of age and his mother were clinically diagnosed as having type 2B von and disease (VWD) based on their increased ristocetin-induced platelet aggregation (RIPA) at a low concentration of ristocetin (0.5mg/mL). Except for the increased RIPA, the levels and multimeric pattern of von Willebrand factor (VWF) in their plasma were indistinguishable from those in type 1 VWD. Bleeding frequencies were low and bleeding symptoms were mild compared with their prolonged bleeding times. Diagnoses were made by direct sequencing of PCR products of A1 domains on the VWF gene derived from the proband and his mother. An Arg543 (CGG) to Trp (TGG) mutation, which is one of the most frequent mutations in type 2B VWD, was detected in both the proband and his mother, and they were heterozygous for this ahnormality. In order to establish a treatment plan for the bleeding episodes, RIPA should be carried out for the determination of indication for desmopressin (DDAVP) at an early stage of diagnosis. The gene analysis should be considered when incompatibility in laboratory findings exists.

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