The fusion between spermatozoon and oocyte represents the final stage of fertilization in mammals.　Since only one of the extremely large number of spermatozoa fertilizes the oocyte, there should be a strictly regulated molecular mechanism in gamete fusion.　Oocyte CD9 was first identified as a key factor for gamete fusion, followed by sperm IZUMO1 and oocyte IZUMO1 receptor JUNO. Since 2020, with the recent emergence of genome editing technologies, new gamete fusion sperm factors, SPACA6, TMEM95, FIMP, SOF1, DCST1, and DCST2, have been reported one after another.　In this review, I would like to give an overview of mammalian gamete fusion based on the latest findings on these factors.

Background: The COVID-19 pandemic has had a significant impact on healthcare, including cancer management.　This study aimed to investigate the prognostic impact of the COVID-19 pandemic, throughout its duration, on patient care for pancreatic ductal adenocarcinoma (PDAC).

Methods: We collected clinical data of patients with unresectable PDAC who underwent palliative chemotherapy at five medical facilities in Fukushima, Japan.　The patients were divided into two groups: group A (nonpandemic cohort) and group B (pandemic cohort).　Survival analysis was performed for progression-free survival (PFS) and overall survival (OS) via the Kaplan‒Meier method with the log-rank test.

Results: In total, 249 patients were selected for the analysis.　Patients in Group B had significantly greater serum CA19-9 levels and proportions of patients selected for combination therapy; however, we did not find significant differences between the two groups in PFS (Group A vs. Group B: 5.6 months vs. 4.4 months, HR = 0.82 (95% CI, 0.6–1.1), p = 0.17) or OS (14.8 months vs. 12.3 months, HR = 0.81 (95% CI, 0.7–1.3), p = 0.81) in the survival analysis.

Conclusions: We did not observe a negative impact on the prognosis of patients with unresectable PDAC throughout the COVID-19 pandemic.

Introduction: Renal arteries vary in their number and arrangement.　Accessory renal arteries (ARA), termed by various names in the literature, can arise from different arterial sources and may be single, double, or multiple.　Understanding these variations is essential for various medical procedures.

Aim: To determine the presence of ARA in the cadavers of South Indian origin and their origin and termination and to discuss its relevant clinical anatomy.

Materials and Methods: This descriptive study utilized 36 adult cadavers of South Indian origin aged between 50 and 80 years.　The ARA observed were classified according to their origin and termination.　The Chi-square test was used to determine the variation in the distribution of accessory arteries between the sides.

Results: Among the 72 kidneys examined, 27.7% had ARA, with a left-sided preponderance.　Most accessory arteries had an aortic origin and hilar or superior polar termination.　Various forms of accessory arteries were observed, including those entering the anterior surface of the kidney, a rare phenomenon.

Conclusion: The incidence of accessory arteries supplying the kidney emphasizes the importance of understanding renal vascular anatomy for clinical practice.　Anatomical variations play a crucial role in selecting donors for renal transplantation and during various renal interventional procedures.

Objectives: To investigate the effect of dyslipidemia on the lower urinary tract function by examining the LDL-C/HDL-C ratio in patients without bladder outlet obstruction (BOO).

Methods: Patients who underwent urodynamic study before robot-assisted radical prostatectomy were included.　Exclusion criteria were diabetes mellitus (HbA1c > 6.2%) and BOO (Schäfer nomogram obstruction III - V).　The association between the preoperative LDL-C/HDL-C ratio and urodynamic findings were analyzed.　Patients were divided into two groups based on Schäfer nomogram: weak contraction group (W−, W+, N−) and strong contraction group (N+, ST) to assess the relationship between the LDL-C/HDL-C ratio and bladder contraction.

Results: A total of 52 patients entered the study.　The LDL-C/HDL-C ratio was 2.4 ± 0.8.　The preoperative international prostate symptom score was mild (6.7 ± 5.6).　Voided volume was significantly positively associated with the LDL-C/HDL-C ratio (P=0.041).　The LDL-C/HDL-C ratio was significantly less in the strong contraction group than in the weak contraction group (P=0.047).　Receiver operating characteristic (ROC) analysis showed a cut-off value of 2.15 for the LDL-C/HDL-C ratio in predicting weak bladder contraction.

Conclusions: Dyslipidemia-induced lower urinary tract dysfunction (LUTD) showed less bladder contractility with larger voided volume.　The LDL-C/HDL-C ratio ≥ 2.15 may be a useful marker of dyslipidemia-induced LUTD.

Objectives: This study investigated whether preoperative patient characteristics and surgery-related factors affect postoperative de novo overactive bladder (OAB) after robot-assisted radical prostatectomy (RARP), and identified three predictive markers.

Methods: Patients without preoperative OAB who underwent RARP at our hospital between February 2013 and October 2020 were included.　At 12 months post-RARP, patients were divided into OAB-free and de novo OAB groups based on the presence of overactive bladder.　Preoperative patient characteristics and surgery-related factors were compared between the two groups.

Results: A total of 404 patients were analyzed (OAB-free group, 338; de novo OAB group, 66).　The preoperative Overactive Bladder Symptom Score (OABSS) and the percentage of patients with dyslipidemia were significantly higher in the de novo OAB group than in the OAB-free group (OABSS, 3.2 ± 1.6 points vs 2.1 ± 1.4, P<0.01; dyslipidemia, 45.5% vs 32.0%, P=0.04).　Nerve-sparing surgery was significantly less common in the de novo OAB group (10.6% vs 27.1%, P<0.01).　Preoperative age, blood pressure, BMI, HbA1c, uroflowmetry parameters, prostate volume, operative time and blood loss showed no significant differences between two groups.

Conclusions: High preoperative OABSS, preoperative dyslipidemia and non-nerve-sparing surgery may be predictive markers for de novo OAB after RARP.

Disasters are becoming more common, and their types are more varied.　This study investigated the extent to which medical students would like to be engaged in different types of disasters to help recruit personnel for future disaster medicine based on a web-based survey.　The study was conducted using existing data.　The results revealed that students’ intention to engage in chemical, biological, radiological, nuclear, and explosive (CBRNE) disasters was lower than that for natural and human-made disasters.　Further, differences in the intention to engage and perceptions of disasters were observed.　We hypothesized that the low intention to engage in CBRNE disasters was due, in part, to the fear of unknown hazards and the belief that disaster response was not part of the university’s mission.　Thus, each university should train healthcare professionals to imagine the social needs of risk and educate students about their intention to engage.　This can be done by showing them how to respond to disasters in the social context of societal demands in case of future crises.

Human herpesvirus 7 (HHV-7) is ubiquitous and infects most children.　Severe HHV-7 infection was considered to be rare.　In this case series, we report the clinical findings and clinical courses of three immunocompetent children who had severe HHV-7 infection: two fatal cases of encephalopathy and one patient with severe sequelae after myocarditis.　In all three patients, HHV-7 DNA was detected in acute phase specimens, including serum by real-time PCR.　In the myocarditis case, HHV-7 DNA was also detected in myocardial tissue, suggesting that HHV-7 was the cause.　Patient 1 was a 6-year-old Japanese girl with encephalopathy who died one day after onset.　Patient 2 was a 4-year-old Japanese girl with encephalopathy whose absence of brainstem reflexes was confirmed and died 29 days after onset.　Patient 3 was a 22-month-old Japanese girl with myocarditis who managed with extracorporeal membrane oxygenation and survived but was left with severe neurological sequelae.　Because HHV-7 can cause serious outcomes in children, a virological search for HHV-7 in severe infections needs to be aggressive, and cases should be accumulated.

Abatacept (ABT) is effective in the treatment of rheumatoid arthritis (RA).　However, there is no consensus regarding the treatment of patients with RA and idiopathic inflammatory myopathy (IIM).　Here, we describe the case of a 55-year-old Japanese female with a 5-year history of RA who developed anti-Jo1 antibody-positive IIM.　She developed myalgia and dyspnea while receiving a combination therapy of methotrexate and a Janus kinase inhibitor for RA.　Chest computed tomography imaging revealed bilateral middle-to-lower lung frosted shadows.　Magnetic resonance imaging of the lower limbs showed a high short tau inversion recovery signal in the bilateral thigh muscle groups.　Needle electromyography revealed myogenic changes in the proximal muscles of both the upper and lower extremities.　Symmetric proximal muscle weakness, elevated serum muscle enzymes, and the presence of anti-Jo1 antibodies were noted.　The diagnosis of IIM was made according to the European Alliance of Associations for Rheumatology diagnostic criteria.　The myositis symptoms stabilized with glucocorticoids; however, RA worsened during steroid tapering.　After ABT initiation, RA clinical symptoms and functional outcomes improved and myositis remained in remission.　In conclusion, ABT may be an effective treatment option for patients with RA and IIM.