Bile Acid Analysis in Biliary Tract Cancer

The etiology of biliary tract cancer is obscure, but there are evidences that bile acid plays a role in carcinogenesis. To find the association between biliary tract cancer and bile acid, this study compared the bile acid concentration and composition among patients with biliary cancer, biliary tract stones, and no biliary disease. Bile was compared among patients with biliary tract cancer (n = 26), biliary tract stones (n = 29), and disease free controls (n = 9). Samples were obtained by percutaneous transhepatic biliary drainage, endoscopic nasobiliary drainage, or gallbladder puncture, and analyzed for cholic, deoxycholic, chenodeoxycholic, lithocholic, and ursodeoxycholic acid composition. Total bile acid concentration was lower in the cancer group than the biliary stone and control groups; the proportions of deoxycholic (2.2% vs. 10.2% and 23.6%, p < 0.001 and p < 0.001, respectively) and lithocholic acid (0.3% vs. 0.6% and 1.0%, p = 0.065 and p < 0.001, respectively) were also lower. This result was similar when disease site was limited to bile duct or gallbladder. Analysis of cases with bilirubin ≤ 2.0 mg/dL also showed lower total bile acid concentration and deoxycholic acid composition in the cancer group compared to controls (5.7% vs. 23.6%, p = 0.003). Although the presence of bile duct obstruction explains some of the difference in total concentration and composition of bile acid, there are other contributing mechanisms. We suspect the alteration of bile acid transport might decrease bile acid excretion and cause the accumulation of carcinogenic bile acid in bile duct epithelium

Differential Regional Immune Response in Chagas Disease

Following infection, lymphocytes expand exponentially and differentiate into effector cells to control infection and coordinate the multiple effector arms of the immune response. Soon after this expansion, the majority of antigen-specific lymphocytes die, thus keeping homeostasis, and a small pool of memory cells develops, providing long-term immunity to subsequent reinfection. The extent of infection and rate of pathogen clearance are thought to determine both the magnitude of cell expansion and the homeostatic contraction to a stable number of memory cells. This straight correlation between the kinetics of T cell response and the dynamics of lymphoid tissue cell numbers is a constant feature in acute infections yielded by pathogens that are cleared during the course of response. However, the regional dynamics of the immune response mounted against pathogens that are able to establish a persistent infection remain poorly understood. Herein we discuss the differential lymphocyte dynamics in distinct central and peripheral lymphoid organs following acute infection by Trypanosoma cruzi, the causative agent of Chagas disease. While the thymus and mesenteric lymph nodes undergo a severe atrophy with massive lymphocyte depletion, the spleen and subcutaneous lymph nodes expand due to T and B cell activation/proliferation. These events are regulated by cytokines, as well as parasite-derived moieties. In this regard, identifying the molecular mechanisms underlying regional lymphocyte dynamics secondary to T. cruzi infection may hopefully contribute to the design of novel immune intervention strategies to control pathology in this infection

Current status of space gravitational wave antenna DECIGO and B-DECIGO

The Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is a future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could have been produced during the inflationary period right after the birth of the Universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the Universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry-Pérot Michelson interferometers with an arm length of 1000 km. Three DECIGO clusters will be placed far from each other, and the fourth will be placed in the same position as one of the other three to obtain correlation signals for the detection of primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder for DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand multi-messenger astronomy