R&D of JAEA for the decommissioning of TEPCO's Fukushima Daiichi nuclear power station.

This paper does not necessarily reflect the views of the International Commission on Radiological Protection.Since the accident at Fukushima Daiichi nuclear power station in March 2011, Japan Atomic Energy Agency (JAEA) has been contributing actively to the environmental recovery of Fukushima and the decommissioning of Fukushima Daiichi nuclear power station from a technical aspect, through a wide range of research and development (R&D) activities including fundamental research and applicational technology development. JAEA has been conducting R&D such as the characterisation of fuel debris, and treatment and disposal of radioactive wastes based on the 'Mid-and-Long-Term Roadmap' authorised by the Japanese Government. This R&D is mainly promoted by Collaborative Laboratories for Advanced Decommissioning Science (CLADS) in Tomioka Town, and CLADS has also been promoting cooperation with domestic and foreign research institutes, related companies, universities, etc. In addition, Naraha Centre for Remote Control Technology Development in Naraha Town commenced full operation in April 2016 for the development and demonstration of remote control technologies planned for use in the decommissioning of Fukushima Daiichi nuclear power station and disaster response. Okuma Analysis and Research Centre in Okuma Town is under construction for the analysis and characterisation of fuel debris and various radioactive wastes. Ten years have passed since the Great East Japan Earthquake and the accident at Fukushima Daiichi nuclear power station, and environmental conditions in Fukushima have been improving. The evacuation zone has been lifted, and preparation of specific recovery areas in the difficult-to-return zone has progressed. However, the reconstruction of Fukushima and the decommissioning of Fukushima Daiichi nuclear power station are still in progress, and JAEA will continue its R&D for the decommissioning of Fukushima Daiichi nuclear power station with domestic and international expertise in order to further contribute to the reconstruction of Fukushima.

Multicenter Study of Intravenous Recombinant Tissue Plasminogen Activator Infusion around Hiroshima, Japan: The Hiroshima Acute Stroke Retrospective and Prospective Registry Study.

OBJECTIVE: Approximately 10 years have passed since intravenous (IV) recombinant tissue plasminogen activator therapy was approved in Japan. The aim of this retrospective study was to identify the effectiveness and safety of IV alteplase therapy with the Japanese original dose around Hiroshima via consideration of the patients' backgrounds, examination findings, and outcomes. METHODS: All consecutive patients with ischemic stroke who received IV alteplase therapy between October 2005 and October 2010 were registered. RESULTS: Four hundred twenty-nine patients with ischemic stroke (172 female [40.1%], mean age 73.7 ± 11.8 years) were registered. The proportion of patients over 75 years old was 51.5% (221 patients). The median National Institutes of Health Stroke Scale (NIHSS) scores at admission were 13 (interquartile range, 9-19), and the NIHSS scores 24 hours after alteplase infusion were 8 (interquartile range, 3-15). The proportion of intracerebral hemorrhage within the initial 36 hours was 20.2% (86 patients). After the multivariate regression analysis, a history of hypertension (odds ratio = 4.14; 95% confidence interval, 1.32-14.79; P = .01) and no recanalization (odds ratio = 10.10; 95% confidence interval, 3.03-39.33; P < .0001) were independently associated with a modified Rankin Scale (mRS) score of 2 or higher at 3 months. Patients over 75 years old were not significantly associated with an intracerebral hemorrhage within the initial 36 hours and an mRS score of 2 or higher at 3 months. CONCLUSIONS: The results of our study demonstrated that IV alteplase therapy with the Japanese original dose was effective and exhibited a safety profile similar to other studies. Moreover, we should not hesitate to IV alteplase therapy simply because of advanced age.

Subsequent vascular events after ischemic stroke: the Japan Statin Treatment Against Recurrent Stroke-Longitudinal.

BACKGROUND: We undertook a multicenter cohort observational study to investigate the frequency and type of subsequent vascular events after an ischemic stroke and to compare the rates of vascular events between patients with and without hyperlipidemia. METHODS: This nationwide study was conducted in 19 hospitals participating in the Japan Standard Stroke Registry Study. We enrolled ischemic stroke patients, including those with a transient ischemic attack, who had not experienced any vascular events before enrollment after their ischemic stroke events. Each subject was observed prospectively from September 1, 2003, to October 1, 2005, or until a primary end point or death. Primary end points included subsequent fatal or nonfatal vascular events: stroke, angina pectoris, acute myocardial infarction, aortic aneurysm, or arteriosclerosis obliterans. RESULTS: A total of 449 patients (mean age, 67.6 years; 64.8% men) were enrolled in this study. Of the 41 vascular events observed during follow-up, 40 were stroke. The median observation period was 568 days. We found that patients with hyperlipidemia had a significantly higher rate of vascular events compared with those without hyperlipidemia according to the Kaplan-Meier method and the log-rank test (P = .013). Hyperlipidemia significantly increased the risk of vascular events (hazard ratio, 2.169 [1.125-4.312]; P = .021) according to the Cox proportional hazard model after adjusting for confounding factors (age, sex, days from ischemic stroke until enrollment, smoking habits, and daily drinking habits). CONCLUSIONS: This study demonstrated that stroke was the most common subsequent vascular event after ischemic stroke; the study also indicated that hyperlipidemia could be a risk factor for subsequent vascular events after ischemic stroke.

Relationship between neuronal loss and tangle formation in neurons and oligodendroglia in progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a progressive degenerative disorder characterized by neuronal loss, gliosis and abnormal fibril formation of abnormally phosphorylated tau protein in neurons and glia cells, but the cause is not clear at present. For the purpose of clarifying the pathological significance of accumulation of tau protein in neurons and oligodendroglia in PSP, we morphologically classified neurofibrillary tangles (NFT) and coiled bodies (CB) in oligodendroglia in three PSP brains into four stages, using double staining for immunohistochemistry with AT8 antibody and modified Gallyas-Braak (GB) staining. AT8-positive neurons without abnormal fibril structure with GB staining were classified as stage I, AT8-positive neurons containing a few fibril structures with GB staining were classified stage II, AT8-positive neurons containing mature fibril structures were classified as stage III, and AT8 negative neurons containing abnormal fibril structures stained only with GB staining were classified as stage IV (ghost tangles). These stages were also assessed for CB. Then we counted the number of cells of each stage in various brain regions to investigate the relationship of NFT and CB with neuronal loss and gliosis. The results showed that there were very few stage IV NFT and CB, which reflect cell death, but that stage III NFT and CB were abundant. Moreover, CB were abundant in regions with severe neuronal loss. These results suggest that appearance of CB is closely associated with degenerative regions.

An unexpected outbreak of Japanese encephalitis in the Chugoku district of Japan, 2002.

Six patients unexpectedly presented with Japanese encephalitis (JE) from early August to mid-September 2002 in the Chugoku district of Japan. The mean age was 67.5 years (range 42 - 89 years); the onset period in two patients shifted to the middle of September. The JE virus was isolated from the cerebrospinal fluid samples from two patients, and the strain isolated in the one was identified as genotype III. Neurologically, consciousness impairment, meningeal signs, rigidity, hemiparesis, tetraparesis, and convulsive seizures were commonly observed. Magnetic resonance imaging uniformly revealed high signal intensities in the bilateral thalami, brainstem (substantia nigra), hippocampi, and brain cortices. In all patients, acyclovir was used, due to the unexpected outbreak of JE. Five patients, except for one without sequelae, had a severe outcome, including one death. This report indicates that JE in Japan is still a threat to adults and the elderly with decreased or absent immunity to the JE virus.

Light and Electron Microscopic Studies on Fertilization of Pelmatohydra Robusta I. Sperm Entry to a Specialized Region of the Egg.

Fertilization of a fresh water polyp, Pelmatohydra robusta, was studied by light and electron microscopy. A small depression was observed in the animal pole of the unfertilized egg. The egg pronucleus was always situated in close contact with the bottom of the depression. Microvilli which were covered with an egg coat consisting of filamentous components were observed on the egg surface. Microvilli and the egg coat were not detected on the surface of the depression. Sperm were associated with the egg plasma membrane and entered the egg only at the bottom of the depression. Excess sperm aggregated around the depression of inseminated eggs. After fertilization, the egg made a protrusion in the region where the egg pronucleus and sperm were in close contact with each other. A new egg coat was formed on the entire surface of the fertilized egg. The restriction of sperm-egg interactions to a specialized region of the hydra egg is discussed in connection with the micropyle of Pisces eggs and the animal dimple of Discoglossus (Anura) eggs.