Risk factors and prediction of bleeding after gastric endoscopic submucosal dissection in patients on antithrombotic therapy: newly developed bleeding prediction application software,SAMURAI model

Bleeding after gastric endoscopic submucosal dissection (ESD) remains problematic, especially in patients receiving antithrombotic therapy. Therefore, this study aimed to identify the risk factors. In this retrospective study, patients (n = 1,207) who underwent gastric ESD while receiving antithrombotic therapy were enrolled at Osaka Medical and Pharmaceutical University Hospital and 18 other referral hospitals in Japan. Risks of post-ESD bleeding were calculated using multivariable logistic regression. The dataset was divided into a derivation cohort and a validation cohort. We created a prediction model using the derivation cohort. The accuracy of the model was evaluated using the validation cohort. Post-ESD bleeding occurred in 142 (11.8%) participants. Multivariable analysis yielded an odds ratio of 2.33 for aspirin, 4.90 for P2Y12 receptor antagonist, 1.79 for cilostazol, 0.95 for other antithrombotic agents, 6.53 for warfarin, 5.65 for dabigatran, 7.84 for apixaban, 10.45 for edoxaban, 6.02 for rivaroxaban, and 1.46 for heparin bridging. The created prediction model was called safe ESD management using the risk analysis of post-bleeding in patients with antithrombotic therapy (SAMURAI). This model had good predictability, with a C-statistic of 0.77. In conclusion, use of the SAMURAI model will allow proactive management of post-ESD bleeding risk in patients receiving antithrombotic therapy.     

Effect of retinoic acid on osteopontin expression in rat clonal dental pulp cells

We studied the effect of retinoic acid on osteopontin synthesis and the mRNA expression in rat clonal dental pulp cells, RPC-C2A. An immunoprecipitation assay clarified that retinoic acid caused an increase in phosphorylated osteopontin synthesis that was dose-dependent, and marked increases were observed at retinoic acid concentrations of 10(-6) to 10(-5) M (1.7-fold). A Northern blotting analysis revealed a similar pattern of increase in osteopontin mRNA expression of up to 6.2-fold of control levels. Because osteopontin has an important role in the mineralization process, these results suggest that retinoic acid regulates mineralization, which takes place in the pulp cavity, including reparative dentin formation.     

Enhanced tumor growth and invasiveness in vivo by a carboxyl-terminal fragment of alpha1-proteinase inhibitor generated by matrix metalloproteinases: a possible modulatory role in natural killer cytotoxicity

Matrix metalloproteinases (MMPs) are believed to contribute to the complex process of cancer progression. They also exhibit an alpha1-proteinase inhibitor (alphaPI)-degrading activity generating a carboxyl-terminal fragment of approximately 5 kd (alphaPI-C). This study reports that overexpression of alphaPI-C in S2-020, a cloned subline derived from the human pancreas adenocarcinoma cell line SUIT-2, potentiates the growth capability of the cells in nude mice. After stable transfection of a vector containing a chimeric cDNA encoding a signal peptide sequence of tissue inhibitor of metalloproteinase-1 followed by cDNA for alphaPI-C into S2-020 cells, three clones that stably secrete alphaPI-C were obtained. The ectopic expression of alphaPI-C did not alter in vitro cellular growth. However, subcutaneous injection of the alphaPI-C-secreting clones resulted in tumors that were 1.5 to 3-fold larger than those of control clones with an increased tendency to invasiveness and lymph node metastasis. These effects could be a result of modulation of natural killer (NK) cell-mediated control of tumor growth in nude mice, as the growth advantage of alphaPI-C-secreting clones was not observed in NK-depleted mice, and alphaPI-C-secreting clones showed decreased NK sensitivity in vitro. In addition, production of alphaPI and generation of the cleaved form of alphaPI by MMP were observed in various human tumor cell lines and in a highly metastatic subline of SUIT-2 in vitro. These results provide experimental evidence that the alphaPI-degrading activity of MMPs may play a role in tumor progression not only via the inactivation of alphaPI but also via the generation of alphaPI-C.     

Morphometric investigation of the hippocampal formation in Ihara's genetically epileptic rats using magnetic resonance images and histopathology

The newly developed Ihara's genetically epileptic rat (IGER) is thought to be a useful tool for studying epilepsy of the limbic type. Morphological changes in the hip-pocampus, which is one of the characteristic findings in the brains of patients with temporal lobe epilepsy, were presumed to occur also in IGER during the course of epileptic activities. We investigated chronological changes in volume of the IGER hippocampal formation using mag-netic resonance (MR) imaging. The experiment consisted of two protocols. First, MR imaging was performed for volumetric measurement of the cerebrum and the hippocampus in four male IGER, each at 2, 4, 6, 8, 10 and 12 months of age. After MR examination, the brains were subjected to histological and morphometric examinations. Second, changes in the hippocampal volume were traced chronologically in three IGER at the ages of 2, 4, 6, 8 and 10 months. Age-matched Wistar rats were used as controls. In IGER, the volume of the cerebrum, especially of the hippocampus, and the ratio of the hippocampal to the cerebral volume increased, in concert with the increase in seizure activities. Histological and morphometric invest-igations revealed that there was mild astrogliosis and marked microgliosis with hypertrophic change in the hippocampal formation with aging, but no loss of neurons was observed. Neither an increase in volume nor gliosis was found in the brains of control rats. The enlargement of the hippocampal formation in IGER brains was assumed to be partially due to gliosis of astrocyte and microglia with hypertrophy.