Intercellular mitochondrial transfer is an emerging therapeutic strategy for restoring cellular function in diseases associated with damaged mitochondrial DNA (mtDNA). However, elucidating the precise dynamics of this process requires robust and long-term tracking tools. Conventional chemical dyes suffer from phototoxicity and signal fading, whereas DsRed, a commonly used red fluorescent protein, forms toxic multimers that accumulate in lysosomes, leading to potential false-negative transfer analyses and a rapid loss of expression over time. To overcome these limitations, we evaluated TurboRFP equipped with a mitochondrial targeting signal (TurboRFPmt) as a superior tracking alternative. Compared to DsRed, TurboRFPmt demonstrated precise mitochondrial colocalization, significantly reduced nonspecific aggregation, higher brightness, and long-term stability without impairing cell proliferation. To validate its efficacy, we employed human amniotic epithelial cells (hAECs)—selected for their stemness and high genomic stability—as mitochondrial donors, and H₂O₂-treated HEK293T cells or HLE r 0 cells as mtDNA damage models. Using 3D confocal microscopy and 24-hour time-lapse imaging, we successfully captured the active transfer and stable cytoplasmic integration of TurboRFP-labeled healthy mitochondria from hAECs into damaged recipient cells. These findings establish TurboRFPmt as a highly reliable and essential tool for advancing the study of intercellular mitochondrial transfer.

Intracellular calcium (Ca²⁺) imaging in living animals has emerged as a powerful approach for examining how cellular activity is integrated into organ-level and whole-body physiology. Unlike ex vivo preparations, in vivo imaging preserves native tissue architecture, blood flow, autonomic input, endocrine regulation, and other systemic influences that shape cellular Ca²⁺ signals. This is particularly important in peripheral organs, although imaging these tissues remains technically challenging due to motion artifacts and optical scattering, which often obscure subtle fluorescence changes. Recent advances in genetically encoded Ca²⁺ indicators (GECIs), genetic targeting strategies, and optical and computational technologies have greatly expanded the feasibility of these experiments. In particular, ratiometric GECIs reduce motion-dependent artifacts and improve measurement reliability in moving tissues. Combined with transgenic strategies, they enable high-level, cell type-specific expression suitable for quantitative in vivo analysis. In this article, we outline the technical background and conceptual basis of mouse in vivo Ca²⁺ imaging, with emphasis on peripheral organs. As an example, we present our approach to in vivo Ca²⁺ imaging of mouse hepatocytes. This application illustrates both the technical challenges of imaging in moving visceral organs and the unique physiological insights obtainable only under intact in vivo conditions.

 Advances in perinatal medicine have markedly improved the survival of preterm infants; however, these children remain at a higher risk of neurodevelopmental impairments (NDIs) than term-born peers. Japan has one of the world's lowest neonatal mortality rates, including those for extremely preterm infants born at 22-24 weeks' gestation, and bears the responsibility of evaluating long-term neurodevelopmental outcomes in this population. Notably, despite high survival rates, the incidence of severe NDIs, such as cerebral palsy, has declined, and overall, NDI rates in Japan are comparable to or lower than those in other high-income countries, suggesting that factors beyond neonatal illness severity contribute to NDI development.

 NDIs include autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder, learning disabilities, and related conditions. In preterm infants, the risk of ASD increases with decreasing gestational age and often presents with atypical features distinct from term-born ASD, known as the “preterm behavioral phenotype.” These characteristics complicate the early detection of ADHD using conventional behavioral and interview-based diagnostic tools.

 Visual cognitive function has emerged as a promising objective marker for early detection. Eye-tracking studies have indicated that preterm infants exhibit atypical gaze patterns, impaired audiovisual integration, and delayed maturation of frontoparietal networks. Using the Gazefinder^® eye-tracking system, our institution demonstrated that the reliable assessment of visual attention in preterm infants becomes feasible from the corrected age of 13-18 months, with chronic lung disease identified as a risk factor for delayed visual cognition. Furthermore, preference-based gaze paradigms have revealed that preterm infants show reduced attention to social stimuli compared with term controls, suggesting a mix of ASD-like and non-ASD characteristics.

 Early developmental intervention is effective for improving cognitive outcomes in preterm children, particularly before the school age. Therefore, integrating visual cognitive assessments with standard neurological examinations and family centered early intervention programs may facilitate the early identification of at-risk infants and enable timely support, ultimately improving long-term social and developmental outcomes.

A 90-year-old man presented with altered consciousness and neck stiffness. Cerebrospinal fluid (CSF) analysis revealed pleocytosis (9,550/μL), elevated protein (3,282 mg/dL), and decreased glucose (1 mg/dL), consistent with bacterial meningitis. The FilmArray^® Meningitis/Encephalitis Panel rapidly identified Streptococcus agalactiae (group B Streptococcus: GBS) in the CSF within approximately 70 min of sample submission on the day of admission, enabling bacterial identification 19 h earlier than the blood culture results. Brain MRI performed on hospital day 11 revealed diffusion-weighted hyperintensities in the fourth ventricle, the posterior horns of both lateral ventricles, and the cerebral sulci, indicating pyogenic ventriculitis. The patient was successfully treated with penicillin G and levofloxacin for 6 weeks. Early diagnosis enables prompt de-escalation to appropriate antibiotics and favorable outcomes. This case highlights the utility of multiplex PCR panels for rapid pathogen identification in bacterial meningitis and suggests that it is particularly important in elderly patients with GBS infections who are at high risk of complications.