Initial gastrointestinal endocrine cells (GIECs) likely appear at the proximal and distal sites of abdominal intestines and may take a close topographical relation with neural elements in the gut. We examined immunohistochemically-stained sections from 10 fetuses at approximately 8–18 weeks of gestational age (36–155 mm of crown-rump length). Irrespective of whether physiological herniation was present (early 5 specimens) or absent (the other 5), the duodenum and jejunum had well-developed mucosa with villi containing abundant flask-like chromogranin-positive cells. In the earlier 5 specimens, the rectum, standing up to a level of the umbilicus, had a lumen and villi with a few positive cells, but the colon carried neither the lumen or chromogranin-positive cells. The initial GIECs seemed to appear in the basal payer of the epithelium at the distal and proximal foci depending on double pathways of neural crest cell migration. Less number of the colic chromograninpositive cells, more than 5-times difference in density relative to small intestine, was seen in the larger 5 specimens. The appearance of GIECs was delayed at the anal transitional zone (a border area between the columnar and squamous epithelia).The reactivity of neuronal nitric oxide synthase was restricted in the myenteric plexus, whereas clusters of slender calretininpositive cells existed in the lamina propria or core of villi in the duodenum and colon. Relatively small, round or oval positive cells were also seen in the basal layer of the columnar epithelium. Therefore, calretinin-positive cells might exist closely to GIECs in the developing villi.

The occipital bone squamosa (OCS) is unique because of its double origin from both endochondral and membranous bones. The present study attempted to demonstrate the process of connection between these two bone types. We examined sagittal and frontal histological sections from 29 human fetuses with a crown-rump length ranging from 38 to 328 mm (approximately 7–39 weeks of gestational age [GA]). An initial cartilage plate appeared in the posterior side of the fourth ventricle at GA 7–8 weeks and extended inferiorly to connect with the cartilaginous basioccipital and condyle. At GA 9–10 weeks, on the superior side of the cartilage plate, membranous bone fragments appeared and adopted an arrangement resembling a chain of irregularly-shaped beads.They did not form a complete plate-like bone until late-term. At GA 11–12 weeks, endochondral ossification centers appeared at the upper and lower ends of the cartilage plate. At GA 12–15 weeks, a bar-like periosteal bone developed near and superior to the upper ossification center. Notably, sinusoidal structures, which were surrounded by growing periosteal bones, contained islandlike clusters of calcified cartilage fragments. Therefore, the upper ossification center appeared likely to “migrate” downward and become distant from membranous bones. The extending periosteal bone reached and joined the membranous bone fragments.Consequently, the periosteal bones connected between the endochondral and membranous bones in the OCS. This connection was quite different from the other components of the calvaria, where membranous bones overlap the skull base cartilages at the margin.

The establishment of enhanced surveillance systems for mass gatherings to detect infectious diseases that may be imported during an event is recommended. The World Health Organization Regional Office for the Western Pacific contributed to enhanced event-based surveillance for the Tokyo 2020 Olympic and Paralympic Games (the Games) by using Epidemic Intelligence from Open Sources (EIOS) to detect potential imported diseases and report them to the National Institute of Infectious Diseases (NIID), Japan. Daily screening of media articles on global infectious diseases was conducted using EIOS, which were systematically assessed to determine the likelihood of disease importation, spread and significant impact to Japan during the Games. Over 81 days of surveillance, 103 830 articles were screened by EIOS, of which 5441 (5.2%) met the selection criteria for initial assessment, with 587 (0.6%) assessed as signals and reported to NIID. None of the signals were considered to pose a significant risk to the Games based on three risk assessment criteria. While EIOS successfully captured media articles on infectious diseases with a likelihood of importation to and spread in Japan, a significant manual effort was required to assess the articles for duplicates and against the risk assessment criteria. Continued improvement of artificial intelligence is recommended to reduce this effort.

In 2021, the National Institute of Infectious Diseases, Japan, undertook enhanced event-based surveillance (EBS) for infectious diseases occurring overseas that have potential for importation (excluding coronavirus disease 2019 [COVID-19]) for the Tokyo 2020 Olympic and Paralympic Summer Games (the Games). The pre-existing EBS system was enhanced using the World Health Organization Epidemic Intelligence from Open Sources system and the BlueDot Epidemic Intelligence platform. The enhanced EBS before and during the Games did not detect any major public health event that would warrant action for the Games. However, information from multiple sources helped us identify events, characterize risk and improve confidence in risk assessment. The collaboration also reduced the surveillance workload of the host country, while ensuring the quality of surveillance, even during the COVID-19 pandemic.

We have developed a new gait assisting device for patients with hemiplegia, by which a single therapist alone can work with : 1) swing of the paretic limb, 2) stance of the paretic limb, and 3) alternate lateral weight-shift during gait. This device (ASSWS : Assistance of Swing, Stance and Weight Shift) imitates the kinesiological complex (patellar ligament, quadriceps, iliotibial ligament and gluteus maximus) to maintain a standing posture for the lower extremities. We compared the results of a gait analysis using a motion analyzer for gait with ASSWS and gait without ASSWS. With ASSWS, the walking speed was faster, stride length was longer, and stride duration was shorter. No differences in floor reaction force were identified. With ASSWS, the flexion peak of the hip joint became larger and the knee joint was in a more flexed position throughout the walking cycle. Also, the joint moment of hip extension, hip flexion and knee extension all increased with use of the ASSWS.