Charcot-Marie-Tooth disease type 1A (CMT1A) is a hereditary neuropathy caused by the duplication of the PMP22 gene, leading to Schwann cell dysfunction and peripheral demyelination. We developed a Schwann cell lineage model derived from induced pluripotent stem cells (iPSCs) obtained from a CMT1A patient. This model exhibited disease-specific phenotypes, providing a valuable platform for investigating the pathophysiology of CMT1A and exploring therapeutic strategies.

　The prevalence of diabetes continues to increase globally, posing a pressing issue for healthcare. Diabetes is primarily characterized by hyperglycemia, resulting from an absolute or relative deficiency in insulin activity, and is associated with systemic micro- and macro-vascular complications. Although diabetes encompasses multiple pathophysiological conditions based on its underlying mechanisms, pancreatic β-cell dysfunction is a common feature.

　Pancreatic β-cells play a critical role in maintaining normal blood glucose levels by producing and secreting insulin in response to blood glucose concentrations. However, when β-cell dysfunction occurs, the cells fail to supply sufficient insulin to meet peripheral insulin demands, resulting in elevated blood glucose levels. Although multiple mechanisms contribute to β-cell impairment, these mechanisms often share overlapping pathways and can interact to exacerbate their detrimental effects.

　Understanding the causes of β-cell dysfunction is essential for the prevention and treatment of diabetes. This review highlights the primary functions of pancreatic β-cells, including insulin biosynthesis and secretion, and provides an overview of the molecular mechanisms underlying β-cell dysfunction.

　I (the author) received the 44th Juntendo Medical School Alumni Association Academic Encouragement Award in May 2022. After graduating from Juntendo University School of Medicine in 2002, I trained in the Department of Coloproctological Surgery at Juntendo University, led by Professor Toshiki Kamano and Professor Kazuhiro Sakamoto. I then studied DNA methylation in cancer at Johns Hopkins University in Maryland in the United States of America from December 2013 to July 2016. I worked in the laboratory of Professor Malcolm V Brock, a thoracic surgeon, in the Department of Thoracic Surgery. The subject of this translational research was ‘Epigenetics’, and specifically DNA methylation in lung and esophageal cancer. Epigenetics is the study of potentially heritable changes in gene expression that do not involve changes to the underlying DNA sequence, while genetics involves changes to the underlying DNA sequence. In epigenetic alterations, methyl marks added to certain bases repress gene activity by tightly packing the chromatin. Recently, there have been many attempts to apply epigenetics to clinical diagnosis, treatment and prevention.

　Colorectal cancer is a global cause of death and an increasingly common disease worldwide. To predict and improve long-term outcomes in CRC, a wide variety of perioperative biomarkers, including imaging markers, blood markers, and pathological and molecular markers, have been reported as prognostic factors. This review includes a description of three of our previous studies on DNA methylation and summarizes the potential clinical usefulness of the findings in precision medicine for colorectal cancer.

Objectives Although the opioid system is critical for regulating itch within the central nervous system, its role in managing severe, treatment-resistant itch related to skin diseases is unclear. Serum lipocalin-2 (LCN-2) levels are associated with the visual analogue scale score of itch in patients with psoriasis vulgaris (PSO), but not other itchy skin diseases. Therefore, we herein investigated the relationship between opioids and LCN-2 with itch in pruritic skin diseases.

Methods We assessed plasma levels of β-endorphin and dynorphin A and serum levels of LCN-2 in patients with pruritic skin diseases using enzyme-linked immunosorbent assays.

Results Plasma dynorphin A levels were significantly reduced in patients with urticaria, and asteatotic dermatitis (AsD), while β-endorphin levels were significantly elevated in those with AsD. The plasma β-endorphin-to-dynorphin A ratio was markedly higher in AsD patients than in healthy controls. Among the patients examined, only those with PSO had significantly elevated serum LCN-2 levels, which correlated with VAS and severity index scores and also with the area of affected skin.

Conclusions The present results suggest that the ratio of plasma opioids is involved in itch control in AsD patients, and serum LCN-2 levels may be a biomarker for itch and its severity in those with PSO.

Objectives Healthcare workers must take stringent infection control measures against coronavirus disease. Previous reports have indicated that N95 respirators cause fatigue, discomfort, and physical symptoms, such as headaches. We aimed to comparatively analyze the effect of the use of surgical and N95 respirators for long hours on the performance of healthcare workers. This is the first study to validate the effect of wearing N95 respirators on work efficiency.

Materials and Methods This study was conducted from April 2021 to October 2021 during the COVID-19 pandemic in Japan. Healthy healthcare workers at an emergency department were subjected to a performance task program comprising four tasks conducted before and after wearing a surgical mask/N95 respirator for at least 4 h, and the results were compared.

Results The study included 17 (male, 8 [47.1%]) healthcare workers. The age ranged from 22 to 32 (mean, 26.6) years. For each task, the rate of change in the percentage of correct responses, rate of decline in reaction time, and rate of decline in reaction time for correct responses were calculated before and after wearing the two types of masks. There was no statistically significant difference in the rate of decline in reaction time between the masks for all tasks. However, there was a trend toward a high rate of decline in the alphanumeric detection task.

Conclusions Using an N95 respirator for 4 h continuously did not adversely affect work efficiency. Although prolonged work under conditions of discomfort should be avoided, it is unlikely that N95 respirators will adversely affect the performance of healthcare workers.