Conjugated bile salts regulate turnover of rat intestinal brush border membrane hydrolases

The mechanisms whereby the conjugated bile salts regulate the activities of the brush border membrane hydrolases and its physiological significance were investigated in rat small intestine, and comparisons were made with the action of pancreatic protease. Rat brush border membrane proteins were metabolically labeled with [³⁵S]methionine, and isolated brush border membrane was incubated with taurocholate or pancreatic elastase. The activity of solubilized hydrolases was assayed and the molecular forms of the hydrolases were examined by SDS-PAGE. The activity and protein bands of alkaline phosphatase and sucrase-isomaltase were solubilized by taurocholate, while alkaline phosphatase was not solubilized by elastase. Solubilized sucrase-isomaltase molecules were proteolytically degraded by elastase, whereas the intact molecule of sucrase-isomaltase was solubilized by taurocholate. Next the physiological role of bile salts in brush border membrane hydrolase turnover were investigated using metabolic labeling of brush border membrane hydrolase and immunoprecipitation in biliary diversion rats. After three days of biliary diversion, a significant increase in alkaline phosphatase activity was observed. Although synthesis of alkaline phosphatase in biliary diversion rats was similar to that observed in control rats, biliary diversion rats showed 1.5-fold slower turnover of alkaline phosphatase when compared with control rats. These results suggest that conjugated bile salts in the intestinal lumen may cause a rapid turnover of brush border membrane hydrolases, which may be increased by the enhanced enzyme degradation. The mechanisms for the enhanced degradation appeared to be solubilization of hydrolases caused by the detergent activity of bile salts. Therefore, conjugated bile salts may play an important physiological role in the regulation of expression of the protease-resistant enzymes such as alkaline phosphatase.     

A case of bullous pemphigoid associated with Pneumocystis pneumonia and Cytomegalovirus pneumonia]

A 68-year-old man was admitted to our hospital presenting cutaneous pruritic lesions consisting of tense blisters with serous content on his arms and legs. Histological findings of skin biopsy confirmed a diagnosis of bullous pemphigoid in March 2005. After 10 weeks of prednisone therapy for bullous pemphigoid, he presented with increasing breathlessness and high fever. He was admitted to our hospital because of severe hypoxemia on May 29, 2005, and mechanical ventilation was started from the first hospital day. Chest computed tomography showed marked ground-glass opacities in both lungs. The levels of beta-D glucan and KL-6 in his sera were elevated. We suspected Pneumocystis pneumonia and Cytomegalovirus pneumonia. Under mechanical ventilation, he received steroid pulse therapy, and sulfamethoxazole-trimethoprim and ganciclovir. A polymerase chain reaction assay of bronchoalveolar lavage fluid showed Pneumocysitis DNA and Cytomegalovirus DNA. On the 12th hospital day, he was weaned from mechanical ventilation. Follow-up chest computed tomography showed marked resolution of diffuse ground-glass opacity in both lungs. We need to consider the development of Pneumocystis pneumonia and Cytomegalovirus pneumonia during steroid therapy for bullous pemphigoid.     

Role of platelets in chronic liver disease and acute liver injury

Platelets contain not only hemostatic factors but also many growth factors that play important roles in wound healing and tissue repair. Platelets have already been used for the promotion of tissue regeneration in the clinical setting, such as dental implantation and plastic surgery. Thrombocytopenia, which is frequently found in patients with chronic liver disease and cirrhosis, is due to various causes such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism. However, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in chronic liver disease are poorly understood. In acute liver injury, it is reported that platelets are recruited to the liver and contribute to liver damage by promoting the induction of chemotactic factors and the accumulation of leukocytes in the liver, whereas platelets or mediators released by platelets can have a protective effect against liver injury. In this review, we highlight the recent accumulated knowledge concerning the role of platelets in chronic liver disease and acute liver injury.     

Plasma Exchange Therapy to Reduce Mortality in Japanese Patients With Diffuse Alveolar Hemorrhage and Microscopic Polyangiitis

Diffuse alveolar hemorrhage (DAH) is well known as a serious complication of microscopic polyangiitis (MPA). We examined the effectiveness of plasma exchange (PLEX) therapy to reduce mortality in Japanese DAH patients with MPA. This retrospective, double‐center, observational cohort study included 20 DAH patients with MPA who were admitted to Juntendo University Hospital or Juntendo Koto Geriatric Medical Center between April 1998 and March 2018. The primary outcome was non–disease‐specific mortality. The 1‐year survival rate of patients with PLEX therapy (N = 4) was higher than that of patients with conventional therapy (N = 16, 75% and 13%, respectively, P = 0.037). Higher values of the 1996 Five‐Factor Score (FFS) and 2009 FFS were associated with increased mortality, with hazard ratios of 2.29 (P = 0.040) and 2.41 (P = 0.043), respectively, by Cox univariate analysis. We investigated PLEX therapy for reducing mortality in DAH patients with MPA, and the 1996 FFS and 2009 FFS were both independent prognostic factors.     

Tensile Properties and Fracture Behavior of Aluminum Alloy Foam Fabricated from Die Castings without Using Blowing Agent by Friction Stir Processing Route

Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%–78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT) observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE) analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis.     

Severe liver injury associated with simeprevir plus pegylated interferon/ribavirin therapy in a patient with treatment-naïve genotype 1b hepatitis C virus: a case report

A second-generation direct-acting antiviral agent, simeprevir, now provides a new treatment option for hepatitis C virus (HCV) infection with good safety profile in combination with pegylated interferon and ribavirin. We herein report a rare case of severe liver injury under simeprevir plus pegylated interferon/ribavirin therapy. We initiated this therapy in a 65-year-old male with treatment-naïve genotype 1b HCV. On day 28, the patient’s HCV-RNA was successfully eliminated, and his liver function was fully restored. However, on day 49, the serum alanine aminotransferase level was elevated at 700 IU/L. The HCV-RNA titer was still undetectable and the involvement of other possible viruses was negligible. A liver biopsy performed on day 60 showed an acute hepatitis pattern. The discontinuation of therapy alone successfully improved his liver damage on day 84. No other treatments such as steroids were required. According to the diagnostic criteria for drug-induced liver injury in Japan (DDW-J2004), the liver injury observed in this case can be associated with the administration of simeprevir plus pegylated interferon/ribavirin therapy. In conclusion, simeprevir plus pegylated interferon/ribavirin should be used with caution, as these agents may cause unreported serious adverse events including severe liver injury, despite their clinical safety profile.