Optogenetic Stimulation of 5-HT Neurons in the Median Raphe Nucleus Affects Anxiety and Respiration

Anxiety affects respiration, and in turn perturbs the internal environment, although the neuronal systems controlling anxiety-related respiration remain unclear. Recent reports indicate that serotonin（5-HT）neurons in the median raphe nucleus（MRN）enhance anxiety. In the present study, we aimed to clarify the contribution of 5-HT neurons in the MRN to anxiety and respiratory control using mice expressing a channelrhodopsin-2 variant-enhanced yellow fluorescent protein（ChR2 ［C128S］-EYFP; a step-function opsin）in the central 5-HT neurons. We applied an optogenetic method to bigenic mice expressing ChR2［C128S］-EYFP in 5-HT neurons and to monogenic mice without such expression. Photostimulation of free-moving mice was performed using a wireless system through an optical fiber pre-inserted above the MRN, and respiratory variables were measured using whole-body plethysmography. Anxiety was evaluated using an elevated-plus maze test. In the bigenic mice, we confirmed ChR2［C128S］-EYFP expression in tryptophan hydroxylase 2（a brain 5-HT synthase）-positive neurons in the raphe nuclei of the mesopontine, such as the MRN and the dorsal raphe nucleus. Blue light illumination to the MRN of the bigenic mice significantly increased respiratory rate and minute ventilation without affecting tidal volume, and significantly decreased the time spent in the open arms of the elevated plus maze without changing distance traveled, compared with monogenic mice. These results suggest that 5-HT neuron activity in the MRN increases anxiety-like behavior without affecting locomotor activity, enhances respiratory rhythm and minute ventilation without changing tidal volume, and can mimic anxiety-related respiratory responses in humans

Effect of neutron irradiation on Nb3Sn wire

A Nb3Sn wire which was manufactured for the ITER toroidal field coil conductor by a bronze route process was prepared for this study to investigate the effect of neutron irradiation on the critical current in a high magnetic field. The critical current of the virgin wire was measured in liquid helium with a 28 T hybrid superconducting magnet at the High Field Laboratory for Superconducting Materials in Tohoku University. It was also measured in vacuum with a heat conduction type variable temperature insert (VTI) at the International Research Center for Nuclear Materials Science at Tohoku University. The wire was irradiated at below 100 °C by fission neutrons at up to 4.9 × 1022 neutrons m−2 (>0.1 MeV) at BR2 in Belgium, and the critical current after the irradiation was evaluated with a VTI in the range of 8–15.5 T. The difference of the critical current measured with two facilities was discussed, focussing on Joule heating of the sample holder which was made of pure copper, and the neutron irradiation effect on the critical current was investigated in the range of up to 15.5 T. The results show that the critical current measured in vacuum becomes lower than that in liquid helium because of the temperature rise of the sample holder where the sample was soldered, the critical current was increased by the neutron irradiation, and the current ratio (IC/IC0) was almost constant of 1.75 in the range of 8–15.5 T at around 4 K

Mice with Calr mutations homologous to human CALR mutations only exhibit mild thrombocytosis

Shide, K., Kameda, T., Kamiunten, A. et al. Mice with Calr mutations homologous to human CALR mutations only exhibit mild thrombocytosis. Blood Cancer J. 9, 42 (2019). https://doi.org/10.1038/s41408-019-0202-

Exit Site Infection due to Mycobacterium chelonae in an Elderly Patient on Peritoneal Dialysis

Nontuberculous mycobacteria (NTM) are rarely isolated from peritoneal dialysis (PD)-associated catheter infections. However, NTM infection is usually difficult to treat and leads to catheter loss. Prompt diagnosis is essential for appropriate treatment. A 70-year-old Japanese man who had been on PD for 2 years and with a medical history of 2 episodes of exit site infections (ESIs) due to methicillin-resistant Staphylococcus aureus was admitted to the hospital due to suspected ESI recurrence. However, Gram staining of the pus revealed no gram-positive cocci. Instead, weakly stained gram-positive rods were observed after 7 days of incubation, which were also positive for acid-fast staining. Rapidly growing NTM Mycobacterium chelonae was isolated on day 14. Despite administering a combination antibiotic therapy, ESI could not be controlled, and catheter removal surgery was performed on day 21. Although PD was discontinued temporarily, the patient did not require hemodialysis, without any uremic symptoms. The catheter was reinserted on day 48, and PD was reinitiated on day 61. The patient was discharged on day 65. Antibiotic therapy was continued for 3 months after discharge, with no indications of recurrent infections observed. It is important to consider the risk of NTM infections in patients on PD. Acid-fast staining could be a key test for prompt diagnosis and provision of an appropriate treatment