IL-1ß and IL-6 activate inflammatory responses of astrocytes against Naegleria fowleri infection via the modulation of MAPKs and AP-1.

Naegleria fowleri, a free-living amoeba, has been found in diverse habitats throughout the world. It causes primary amoebic meningoencephalitis in children and young adults. The amoeba attaches to nasal mucosa, migrates along olfactory nerves and enters the brain. Astrocytes are involved in the defence against infection and produce inflammatory responses. In this study, we focus on the mechanism of immune responses in astrocytes. We showed, using RNase protection assay, RT-PCR and ELISA in an in vitro culture system, that N. fowleri lysates induce interleukin-1beta (IL-1ß) and IL-6 expression of astrocytes. In addition, cytokine levels of astrocytes gradually decreased due to extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 inhibitors. To determine the transcription factor, we used transcription inhibitor (AP-1 inhibitor), which downregulated IL-1ß and IL-6 expression. These results show that AP-1 is related to IL-1ß and IL-6 production. N. fowleri-mediated IL-1ß and IL-6 expression requires ERK, JNK and p38 mitogen-activated protein kinases (MAPKs) activation in astrocytes. These findings show that N. fowleri-stimulated astrocytes in an in vitro culture system lead to AP-1 activation and the subsequent expressions of IL-1ß and IL-6, which are dependent on ERK, JNK and p38 MAPKs activation. These results may imply that proinflammatory cytokines have important roles in inflammatory responses to N. fowleri infection.

Endoscopic treatment of difficult bile duct stones by using a double-lumen basket for laser lithotripsy--a case series.

Laser lithotripsy is an effective and safe method for difficult common bile duct (CBD) stones. However, radiolucent laser fibers make accurate fragmentation difficult and require continuous visual control or an accessory for effective targeting. The newly developed double-lumen basket may promote effective laser lithotripsy after stone capture. We performed laser lithotripsy using a double-lumen basket in 14 patients with CBD stones refractive to conventional endoscopic treatment, and evaluated the feasibility and efficacy of this procedure. Stones were successfully fragmented in 13 of 14 patients, and 13 patients eventually became stone-free. Mechanical lithotripsy was applied in two patients with biliary strictures. Minor complications were noted in three patients, including transient hemobilia in one patient. For a selected group of patients with difficult CBD stones, laser lithotripsy using a double-lumen basket appears to be an effective and safe method. However, continuous development of basket protocols to increase the success rate of lithotripsy is needed.