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Despite the global implementation of COVID-19 mitigation measures, the disease continues to maintain transmission. Although mask wearing became one of the key measures for preventing the transmission of COVID-19 early in the pandemic period, many countries have relaxed the mandatory or recommended wearing of masks. The objective of the present study was to estimate the epidemiological impact of removing the mask-wearing recommendation in Japan. We developed a model to assess the consequences of declining mask-wearing coverage after the government revoked its recommendation in February 2023. The declining mask-wearing coverage was estimated using serial cross-sectional data, and a mathematical model was devised to determine the age-specific incidence of COVID-19 using the observed case count in Tokyo from week of October 3, 2022 to October 30, 2023. We explored model-based counterfactual scenarios to measure hypothetical situations in which the mask-wearing coverage decreases or increases relative to the observed coverage. The results show that mask-wearing coverage declined from 97% to 69% by the week of October 30, 2023, and that if the mask-wearing recommendation had continued, 427 lives could have been saved in Tokyo. If the mask-wearing coverage had declined to 25% of the observed level, the model suggests there might have been 1587 additional deaths. Thus, revoking the mask-wearing recommendation had a substantial epidemiological impact. In future pandemics, our proposed approach could provide a real-time quantification of the effects of relaxing countermeasures.

Background and Aims: Physiologic ICSI (PICSI) is a method of ICSI in which sperm attached to hyaluronic acid (HA) are selected. It is known that mature sperm express receptors for adhesion to the HA due to reconstruction of the protoplasmic membrane. In fact, it has been confirmed that sperm that can adhere to HA are mature sperm, and it has been reported that their DNA is highly normal. However, previous studies on the clinical outcomes of PICSI have shown inconsistent results. Therefore, the purpose of this study was to evaluate the clinical usefulness of PICSI using sibling oocytes. Method: The 365 cycles in which two or more mature oocytes were obtained in ICSI cycles were included, and the sibling oocytes of the same cycle were equally divided between conventional ICSI and PICSI methods. Sperm selection was based on sperm morphology and motility in the conventional method, while adhesion to HA was taken into account in the PICSI method. The evaluation items were embryonic developmental potential and clinical pregnancy and miscarriage rates after single frozen thawed blastocyst transfer. Results: The normal fertilization rates for the conventional and PICSI methods were 81.3% and 80.8%, respectively; the blastocyst rates were 64.7% and 68.2%, respectively; and the good blastocyst rates were 30.8% and 31.8%, respectively. There were no significant differences in any of the endpoints (Table 1). There were no significant differences between the two groups in clinical pregnancy and miscarriage rates after single frozen thawed blastocyst transfer (Table 2). Conclusion: In the patients in this study, the clinical outcomes of PICSI were equivalent to those of the conventional method, and the clinical benefit of PICSI was not demonstrated. In the future, it will be necessary to examine the conditions under which PICSI is effective.

Abstract Accumulating evidence suggests that elevated inflammation contributes to the pathophysiology of post-traumatic stress disorder (PTSD) and that anti-inflammatory drugs might be a new treatment strategy for PTSD. It has been reported that beta-hydroxybutyrate (BHB), one of the main ketone bodies produced, can have an anti-inflammatory and antidepressant effect. Here, we investigated the potential anti-anxiety and anti-inflammatory effects of BHB using a rodent PTSD model, induced by single prolonged stress (SPS). Male, Sprague–Dawley rats were employed in this study. Repeated administration of BHB attenuated SPS-induced anxiety-related behaviors evaluated by the elevated plus maze test. SPS increased the serum levels of TNF-α and IL-1β. In contrast, BHB administration partially attenuated the increase of serum TNF-α. These findings demonstrate that BHB exerts its anxiolytic effects, possibly by inhibiting systemic TNF-α. Hence, BHB may be a novel therapeutic candidate for the treatment of PTSD.

Abstract Aims Neuroinflammation is deeply related to the pathophysiology of depression. Beta‐hydroxybutyrate (BHB), which is an endogenous ketone body, exerts anti‐inflammatory effects, and peripheral administration of BHB induces antidepressant effects in an animal model of depression; however, it is unclear whether BHB specifically mediates these actions in the brain. Thus, we administered BHB directly into the brain in a rodent model of depression using a chronic unpredictable stress (CUS) paradigm. Methods BHB was continuously microinjected into the prefrontal cortex (PFC) using osmotic pumps for 21 days. Behavioral testing included the forced swim test (FST) and the open field test (OFT); the levels of pro‐inflammatory cytokines, such as interleukin 1β (IL‐1β) and tumor necrosis factor α (TNF‐α), were quantified in the PFC, and the concentration of corticosterone in blood serum was measured. Results BHB administration into the PFC significantly decreased immobility time in the FST, without significantly altering locomotor activity assessed in the OFT. Also, CUS significantly increased the levels of TNF‐α in the PFC and decreased serum corticosterone levels; these changes were attenuated by BHB administration. These findings suggest that a small amount of BHB administered into the PFC directly produces antidepressant effects, possibly through anti‐inflammatory mechanisms, and can improve hypothalamus‐pituitary‐adrenal axis responses. Conclusion BHB may be a novel therapeutic candidate for the treatment of depression based on the neuro‐inflammatory hypothesis, and the PFC is a region implicated in the antidepressant action of BHB.