ADAMTS13によるvon Willebrand因子の切断増加は、本態性血小板血症患者における後天性von Willebrand症候群の発症に強く寄与する。

Background: Patients with essential thrombocythemia (ET) often experience bleeding associated with acquired von Willebrand syndrome (AVWS) when the platelet count is markedly increased. Objective: We investigated whether von Willebrand factor (VWF) degradation is enhanced in patients with ET. Methods: Seventy patients with ET underwent VWF multimer (VWFM) analysis and measurement of VWF-related parameters. We calculated the VWFM index, defined as the ratio of intensities of a patient's molecular weight-categorized VWFMs, and those of a healthy subject's, using densitometric analysis. VWF degradation product (DP) was measured via ELISA using a monoclonal antibody that specifically recognizes Y1605 at the C-terminal boundary, which is exposed following ADAMTS13-mediated cleavage of the Y1605-M1606 bond of the VWF A2 domain. Results: Patients with higher platelet counts had a significantly reduced high molecular weight (HMW)-VWFM index and an increased VWF-DP: VWF antigen (Ag) ratio compared to those with lower platelet counts. On multivariate analysis, the VWF-DP/ VWF:Ag ratio was an independent predictor of the HMW-VWFM index. Patients who underwent cytoreductive therapy had a significantly higher HMW-VWFM index and lower VWF-DP/ VWF:Ag ratio than those who did not. Among individual patients, there was also a significant increase in the HMW-VWFM index and a decrease in the VWF-DP/ VWF:Ag ratio after cytoreductive therapy compared to pre-therapy values. Conclusion: In patients with ET, an increased platelet count is associated with enhanced cleavage of VWF at the Y1605-M1606 bond, primarily by ADAMTS13, leading to AVWS. Cytoreductive therapy reduces the platelet count, prevents excessive VWF cleavage, and improves VWFM distributions.博士（医学）・甲第881号・令和5年3月15

Three-dimensional sodium chloride (NaCl) model for simulated mandibular reconstruction surgery : a new environmentally friendly material

Background : Mandibular reconstruction using a fibular graft is a difficult procedure that requires technical expertise to enable adequate occlusal function and restore an aesthetic appearance. Here we used three-dimensional (3D) sodium chloride (NaCl) models for simulated mandibular reconstruction surgery. This study aimed to reveal the accuracy of mandibular reconstruction with fibular grafts using this model. Methods : Mandibular reconstructions using 3D NaCl models were performed in 5 cases. The maxilla, mandible, and fibular models were developed using computed tomography (CT) data. We performed preoperative cutting and simulation surgery using this model. Angles between the body of the corpus and symphysis were measured from the axial view (n = 4). Angles between the ramus and the body of the corpus were measured from the lateral and axial views (n = 6). These angles were measured on simulated models and postoperative CT images were compared. Results : Differences between the angles measured on the simulated models and postoperative CT images were 0-5°(mean, 1.9°). Conclusions : We were able to reproduce the neomandibles with precise osteotomies using the 3D NaCl models. We believe that simulated mandibular reconstruction surgery using this model might help reduce the number of intraoperative neomandibular segment adjustments

Successful Emergency Endoscopic Treatment of Gastric Outlet Obstruction due to Gastric Bezoar with Gastric Pneumatosis

Gastric bezoars are rare and are usually found incidentally. They can sometimes cause severe complications, including gastric outlet obstruction (GOO) or gastric pneumatosis (GP). In cases of bezoars with GP, the optimal treatment strategy has not yet been defined. We report the case of an 89-year-old man with a history of type 2 diabetes mellitus and hypertension who presented to our emergency room with a 2-day history of upper abdominal pain, nausea, and vomiting. Physical examination revealed no rebound tenderness or guarding, and laboratory values revealed no elevation of the serum lactate level. A computed tomography scan of the abdomen showed a dilated stomach with significant fluid collection, GOO, and GP due to a 42 × 40 mm mass composed of fat and air densities. Emergency esophagogastroduodenoscopy revealed two gastric bezoars, one of which was incarcerated in the pyloric region. We used various endoscopic devices to successfully break and remove the bezoars. We used endoscopic forceps and a water jet followed by an endoscopic snare to cut the bezoars into several pieces and remove them with an endoscopic net. Follow-up endoscopy confirmed that the gastric bezoar had been completely removed. As seen in this case, endoscopic treatment may be a safe and viable option for the extraction of gastric bezoars presenting with GOO and GP

Development of an Automated Chemiluminescent Enzyme Immunoassay for Measuring Thrombopoietin in Human Plasma

Plasma thrombopoietin (TPO) measurements help distinguish between different types of thrombocytopenia but are not feasible in routine clinical practice. We developed a fully automated quantitative chemiluminescent enzyme immunoassay (CLEIA) for measuring TPO (TPO-CLEIA), which is a one-step sandwich-type assay. This assay utilizes a mouse monoclonal capture antibody, which has the neutralizing epitope of the interaction between TPO and the TPO receptor, and a newly generated rabbit monoclonal detector antibody. In analytical performance studies, this assay showed good linearity over the measuring range and high sensitivity. The limit of quantification (LoQ) of this assay was 3.4 pg/mL; low TPO concentration values of almost all healthy individuals exceeded the LoQ value. In clinical validation studies, TPO levels obtained from patients with aplastic anemia (AA) significantly increased, whereas those of patients with immune thrombocytopenia (ITP) were normal or slightly increased. The cutoff value for TPO-CLEIA corresponding to the previously reported values was useful for distinguishing between ITP and AA. These results suggest that TPO-CLEIA can quantify human plasma TPO levels with high accuracy and sensitivity and has the potential to facilitate routine clinical measurement of TPO in patients with various types of thrombocytopenia