Industrial separation of oxygen isotopes by oxygen distillation

¹⁸O‐labeled water (Water‐¹⁸O) is a widely used starting material of ¹⁸F‐labeled diagnostic agents in positron emission tomography (PET). Conventionally, Water‐¹⁸O has been separated from other stable oxygen isotope species (¹⁶O, ¹⁷O) by water distillation or nitric oxide distillation. However, conventional methods are costly and may have safety issues. In 2004, we developed the first unit of our novel oxygen isotope separation process by cryogenic oxygen distillation to overcome these issues. To meet the needs of the market, we built a second unit in 2013 and a third in 2016. We are now operating three commercially viable separation units with a total capacity of 600 kg of Water‐¹⁸O per year.     

Inhibitory Effects of Pepstatin A and Mefloquine on the Growth of Babesia Parasites

We evaluated the inhibitory effects of pepstatin A and mefloquine on the in vitro and in vivo growths of Babesia parasites. The in vitro growth of Babesia bovis, B. bigemina, B. caballi, and B. equi was significantly inhibited (P < 0.05) by micromolar concentrations of pepstatin A (50% inhibitory concentrations = 38.5, 36.5, 17.6, and 18.1 μM, respectively) and mefloquine (50% inhibitory concentrations = 59.7, 56.7, 20.7, and 4 μM, respectively). Furthermore, both reagents either alone at a concentration of 5 mg/kg or in combinations (2.5/2.5 and 5/5 mg/kg) for 10 days significantly inhibited the in vivo growth of B. microti in mice. Mefloquine treatment was highly effective and the combination treatments were less effective than other treatments. Therefore, mefloquine may antagonize the actions of pepstatin A against babesiosis and aspartic proteases may play an important role in the asexual growth cycle of Babesia parasites.     

A case of malignant peritoneal mesothelioma successfully treated with systemic chemothrapy

A 64-year-old man with a 2-month history of abdominal distension was admitted for transient cerebral ischemic attack. A CT scan revealed massive ascites. Laparoscopy showed multiple whitish nodules on the visceral peritoneum and the omentum. Peritoneal biopsy revealed tumor cells consistent with malignant peritoneal mesothelioma (MPeM). Pemetrexed in combination with cisplatin was administered because it has been reported to be active in patients with MPeM. However his disease progressed. As second-line therapy paclitaxel was tried which yielded a complete response (CR). Eighteen months later he developed abdominal pain of the right upper region where a CT scan showed a mass with surrounding inflammation. As third-line therapy, gemcitabine was administered and again resulted in a CR. He is alive at 3 years from first presenting. Searches for case studies published in medical journals on MPeM were carried out, and 59 cases were analyzed in comparison with this case.     

Successful radiofrequency catheter ablation of common atrial flutter at the bottom of a coronary sinus diverticulum

We describe a patient who underwent radiofrequency (RF) catheter ablation of cavo-tricuspid isthmus-dependent atrial flutter (AFL). Extensive ablation at the isthmus failed to terminate the AFL. A coronary sinus (CS) diverticulum arising from the proximal portion of the middle cardiac vein was found near the isthmus. An RF energy application at the bottom of the CS diverticulum resulted in completion of a bidirectional block line at the isthmus, as well as AFL termination.     

Case of immunoglobulin G4-related cholangitis accompanying autoimmune pancreatitis: diagnosis by peroral cholangioscopy and treatment by endoscopic biliary stenting

Recently, the progress of endoscopy has made it possible to evaluate bile duct mucosa by peroral cholangioscopy. Herein, we report a case of immunoglobulin G4-related sclerosing cholangitis accompanying autoimmune pancreatitis in a patient who improved with treatment by steroid therapy and endoscopic biliary stenting, and observed the bile duct mucosa by peroral cholangioscopy before and after treatment.     

Strategy to differentiate autoimmune pancreatitis from pancreas cancer

Autoimmune pancreatitis (AIP) is a newly described entity of pancreatitis in which the pathogenesis appears to involve autoimmune mechanisms. Based on histological and immunohistochemical examinations of various organs of AIP patients, AIP appears to be a pancreatic lesion reflecting a systemic "IgG4-related sclerosing disease". Clinically, AIP patients and patients with pancreatic cancer share many features, such as preponderance of elderly males, frequent initial symptom of painless jaundice, development of new-onset diabetes mellitus, and elevated levels of serum tumor markers. It is of uppermost importance not to misdiagnose AIP as pancreatic cancer. Since there is currently no diagnostic serological marker for AIP, and approach to the pancreas for histological examination is generally difficult, AIP is diagnosed using a combination of clinical, serological, morphological, and histopathological features. Findings suggesting AIP rather than pancreatic cancer include: fluctuating obstructive jaundice; elevated serum IgG4 levels; diffuse enlargement of the pancreas; delayed enhancement of the enlarged pancreas and presence of a capsule-like rim on dynamic computed tomography; low apparent diffusion coefficient values on diffusion-weighted magnetic resonance image; irregular narrowing of the main pancreatic duct on endoscopic retrograde cholangiopancreatography; less upstream dilatation of the main pancreatic duct on magnetic resonance cholangiopancreatography, presence of other organ involvement such as bilateral salivary gland swelling, retroperitoneal fibrosis and hilar or intrahepatic sclerosing cholangitis; negative work-up for malignancy including endoscopic ultrasound-guided fine needle aspiration; and steroid responsiveness. Since AIP responds dramatically to steroid therapy, accurate diagnosis of AIP can avoid unnecessary laparotomy or pancreatic resection.