Positive Ratio of Polymerase Chain Reaction (PCR) and Validity of Pre-Screening Criteria at an Outpatient Screening Center during the Early Phase of the COVID-19 Epidemic in Japan.

Despite the increase in COVID-19 cases globally, the number of cases in Japan has been relatively low, and an explosive surge in the prevalence has not occurred. In March 2020, the Ministry of Health, Labour and Welfare (MHLW) in Japan recommended the original criteria for polymerase chain reaction (PCR) testing, although there was a lack of evidence for appropriate targets for COVID-19 testing. This study aimed to evaluate the COVID-19 positive ratio and pre-screening criteria in Tokyo immediately after the insurance-covered SARS-CoV-2 PCR testing became available in Japan. We subjected 277 individuals with mild symptoms in metropolitan Tokyo (positive: 9.0%) from March 9 to 29, 2020, to SARS-CoV-2 PCR testing. The results revealed that 25 (9.0%) of them were PCR-positive. The sensitivity and specificity of the MHLW criteria were 100% and 10.7%, respectively. When the criteria excluded nonspecific symptoms, fatigue, and dyspnea, the sensitivity slightly decreased to 92%, and the specificity increased to 22.2%. The specificity was highest when the fever criterion was ≥37.5°C for ≥4 days, and exposure/travel history, including age and underlying comorbidities, was considered. Our findings suggest that the MHLW criteria, including the symptoms and exposure/travel history, may be useful for COVID-19 pre-screening.

A breathing movement sensor for chest radiography during inspiration in children aged less than 3 years: a prospective randomized controlled study.

Chest radiographs should be obtained at the peak of inspiration so that radiological findings can be precisely interpreted. However, this is not easily achieved, particularly in young children who do not follow the instruction to hold their breath. We developed a sensor that detects the breathing movements and conducted a randomized controlled study to determine whether the sensor would increase the proportion of chest radiographs obtained in the inspiration phase. We recruited 124 infants and children aged less than 3 years, who visited the pediatric department of a general hospital in Tokyo, Japan, and allocated them into one of two groups: with-sensor and without-sensor groups. Overall, 81% of all images were obtained during inspiration. The proportion of chest radiographs taken during inspiration was not statistically different between the two groups (81% vs. 82%). In the with-sensor group, radiologic technologists were able to obtain chest radiographs of the same quality while not observing the chest movement, but the sensor. The use of the sensor did not increase the proportion of chest radiographs taken in the inspiration phase in this study. However, this null result may indicate the possibility of utilizing the sensor for automatizing chest radiography in the future.

[A case of anaphylaxis caused by enokitake (Flammulina velutipes) ingestion].

Enokitake (Flammulina velutipes, winter mushroom) is a common edible mushroom in Japan. We experienced a case of anaphylaxis after enokitake ingestion. There are no reports describing anaphylaxis caused by the ingestion of this mushroom. Enokitake allergen has also not been reported. We thus attempted to identify enokitake allergen using the patient's serum. The patient was a seventeen-year-old woman who had had no episodes of food allergy and experienced anaphylaxis after the ingestion of sukiyaki (beef, pork, tofu, vegetables, enokitake, etc.). She had previously eaten sukiyaki (the same ingredients) without any symptoms. The result of enokitake skin prick to prick test was positive. Oral food challenge was positive, inducing anaphylaxis. We performed western blotting with enokitake extract and the patient's serum. Three enokitake protein bands (18 kDa, 39 kDa, 50 kDa) reacted specifically with the patient's IgE.