Endoscopic ultrasonography (EUS) and magnetic resonance imaging (MRI) are becoming popular methods for examining tumorous lesions along the upper gastrointestinal tract. Though duplication cysts are uncommon, EUS findings from gastric duplication cysts have accumulated and proven very useful for preoperative diagnosis. There have been few reports, however, concerning MRI findings from these cysts. We report herein the case of a 25-year-old man with a gastric duplication cyst. EUS demonstrated a cystic mass adjacent to the fourth layer of the stomach wall. MRI revealed a cyst containing low signal-intensity fluid and high signal-intensity fluid separated by levels. In addition to the characteristic findings from preoperative examinations, the unique histological findings from the cyst are also described.

Wild-derived mice have long offered invaluable experimental models for mouse genetics because of their high evolutionary divergence from laboratory mice. A number of wild-derived strains are available from the RIKEN BioResource Center (BRC), but they have been maintained as living stocks because of the unavailability of assisted reproductive technology (ART). In this study, we sought to devise ART for 37 wild-derived strains from five subspecies of Mus musculus maintained at the BRC. Superovulation of females was effective (more than 15 oocytes per female) for 34 out of 37 strains by treatment with either equine chorionic gonadotropin or anti-inhibin serum, depending on their genetic background (subspecies). The collected oocytes could be fertilized in vitro at mean rates of 79.0% and 54.6% by the optimized protocol using fresh or frozen-thawed spermatozoa, respectively. They were cryopreserved at the 2-cell stage by vitrification with an ethylene glycol-based solution. In total, 94.6% of cryopreserved embryos survived the vitrification procedure and restored their normal morphology after warming. A conventional embryo transfer protocol could be applied to 25 out of the 35 strains tested. In the remaining 10 strains, live offspring could be obtained by a modified embryo transfer protocol using cyclosporin A treatment and co-transfer of ICR (laboratory mouse strain) embryos. Thus, ART for 37 wild-derived strains was devised successfully and is now routinely used for their preservation and transportation. The information provided here might facilitate broader use and wider distribution of wild-derived mice for biomedical research.

The stainability of proliferating cells with monoclonal antibodies to both bromodeoxyuridine (BrdU) and Ki-67 were compared in 22 malignant lymphomas and six related conditions. A significant correlation was observed (r = 0.78) between the positivities of proliferating cells determined using these two monoclonal antibodies. The growth fractions determined with the antibodies were usually related to the histologic classification, but labelling index was more varied in diffuse large cell type lymphoma. BrdU labelling was well correlated with the Working Formulation, and more useful as a prognostic indicator. On the other hand, Ki-67 was useful for broad recognition of cell proliferative ability.

We describe herein the case of a 45-year-old man who developed a periosteal chondroma in a rib at the site of a thoracotomy that had been performed 24 years previously. To our knowledge, this is only the third case of a periosteal chondroma in a rib to be documented in the world literature. Some authors have suggested that trauma, including that of surgery, may induce chondroma formation and this association could have been an important contributing factor in the induction of the tumor in this patient.

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