Clinical Characteristics of Patients with SARS-CoV-2 N501Y Variants in General Practitioner Clinic in Japan.

The clinical characteristics of patients with N501Y mutation in SARS-CoV-2 variants (N501YV) is not fully understood, especially in the setting of general practice. In this retrospective cohort study, COVID-19 patients admitted to one general practitioner clinic between 26 March and 26 May 2021 were retrospectively analyzed. The characteristics, clinical symptoms and radiological findings before treatment were compared between N501YV and wild-type 501N. Twenty-eight patients were classified as wild-type 501N and 24 as N501YV. The mean (±standard deviation) age was 37.4 (±16.1) years, with no significant difference between groups. Among clinical symptoms, prevalence of fever of 38 degrees Celsius (°C) or higher was significantly higher in the N501YV group than in the wild-type 501N group (p = 0.001). Multivariate analysis showed that fever of 38 °C or higher remained significantly associated with N501YV (adjust odds ratio [aOR]: 6.07, 95% confidence interval [CI]: 1.68 to 21.94). For radiological findings, the lung involvement area was significantly larger in patients infected with N501YV (p = 0.013). In conclusion, in the N501YV group, fever of 38 °C or higher and extensive pneumonia were more frequently observed compared to the wild-type 501N group. There was no significant difference in terms of other demographics and clinical symptoms.

Phase I clinical study of NMB58, a novel positron emission tomography (PET)-myocardial perfusion imaging tracer, conducted to evaluate its safety and pharmacokinetics in Japanese healthy adult males.

OBJECTIVES: NMB58 is a novel positron emission tomography (PET) tracer containing flurpiridaz as an active ingredient and available as a myocardial perfusion imaging tracer that targets mitochondrial complex 1. A phase I clinical study of NMB58 was conducted to evaluate its safety and pharmacokinetics in healthy volunteers. METHODS: Ten healthy Japanese volunteers received bolus injection of NMB58 (111-167 MBq) intravenously and underwent imaging studies at rest on day 1. Of these subjects, 5 (day 2 cohort 1; exercise stress) and 5 (day 2 cohort 2; pharmacological stress) similarly underwent stress imaging studies on day 2. The safety of NMB58 was evaluated through monitoring of signs/symptoms, electrocardiography, vital signs, and laboratory examinations at baseline and several time points during 3 days. Sequential whole-body positron emission tomography-computed tomography (PET/CT) scan data were acquired for up to 5-h post-injection, with venous blood and urine samples collected for up to 8-h post-injection. Based on the results of the biodistribution study, the absorbed radiation dose (Rad) was estimated by the Medical Internal Radiation Dose method. RESULTS: On day 1, the kidneys were shown to have the highest Rad, followed by the myocardium. On day 2, the myocardium was shown to have the highest Rad, followed by the kidneys. The mean effective doses (EDs) per unit activity administered were 0.021, 0.017 and 0.021 mSv/MBq for overall subjects (day 1), day 2 cohort 1 and day 2 cohort 2, respectively. The estimated exposure dose of NMB58 was similar to or lower than those of radiotracers currently approved for clinical use, including 18F-Fludeoxyglucose. Biodistribution results indicated that NMB58 distributed to the myocardium exhibited high and sustained retention after administration. The cumulative urinary radioactivity excretion rate was shown to be 6.9, 2.3%, and 8.0% of the injected dose in overall subjects (day 1), day 2 cohort 1 and day 2 cohort 2. There were no drug-related adverse events, and the tracer was well tolerated in all subjects. CONCLUSIONS: Based on radiation dosimetry, biodistribution, and safety evaluations, NMB58 was found to be a suitable tracer for clinical use in PET myocardial perfusion imaging during exercise or pharmacological stress.

Predictive ability and interobserver reliability of computed tomography findings for angioembolization in patients with pelvic fracture.

BACKGROUND: The purpose of this study was to identify computed tomography (CT) findings that predict the need for angioembolization in patients with pelvic fracture. METHODS: This retrospective cross-sectional study was performed between April 2006 and October 2015 at two urban emergency medical centers in Japan. The study included patients who underwent CT within 3 hours of arrival and were diagnosed with a pelvic fracture. The study outcome was undergoing angioembolization within 24 hours of arrival. Four independent readers blinded to all clinical information interpreted the CT scans for blush, thickness of retroperitoneal hematoma, and diameter and laterality of muscle swelling around the pelvis. Receiver operating characteristics analyses provided area under the receiver-operating characteristic curves (AUROC) and diagnostic indicators at the estimated thresholds including sensitivity, specificity, positive and negative predictive values and diagnostic odds ratio (DOR). The interobserver reliability of all radiographic findings was also evaluated. RESULTS: Fifty-two of 244 eligible patients underwent angioembolization. The predictive ability in terms of DOR was relatively better with blush on CT scan (sensitivity, 0.57; specificity, 0.86; DOR, 8.05) than with laterality of muscle swelling of 12.9 mm or greater (sensitivity, 0.79; specificity, 0.55; DOR, 4.60; AUROC, 0.75) and thickness of retroperitoneal hematoma of 22.7 mm or greater (sensitivity, 0.65; specificity, 0.74; DOR, 5.39; AUROC, 0.73). The interobserver reliability of blush, laterality of muscle swelling, and thickness of retroperitoneal hematoma was 0.43, 0.54, and 0.70, respectively. CONCLUSION: All of the tested CT findings failed to show both sufficient predictive ability and sufficient interobserver agreement. Further diagnostic accuracy studies to validate these findings or establish a prediction model incorporating these findings are expected. LEVEL OF EVIDENCE: Diagnostic, level V.