Izumi Nishidate

Hypoxic-ischemic encephalopathy (HIE), which precipitates during parturition, causes severe neurological sequelae in the neonate. We have previously reported an optical monitoring system based on diffuse reflectance spectroscopy to evaluate brain tissue damage that precedes HIE. This study aimed to evaluate the effects of resveratrol on the suppression of HIE development using this monitoring system. After left carotid artery ligation, neonatal rats were intraperitoneally injected with 20 or 40 mg/kg resveratrol and subjected to hypoxic stress. HIE lesions were assessed after 24 h using triphenyl tetrazolium chloride staining. HIE developed in the non-treated group and the group treated with 20 mg/kg administration. Optical parameter assessment during hypoxic stress revealed that HIE-induced brain damage was characterized by a decrease in scatter amplitude, an increase in total hemoglobin in the cerebral blood flow, and a reduction in tissue oxygen saturation. HIE development was completely suppressed in the 40 mg/kg group, in which the changes in the optical parameters were also suppressed. These findings suggest that resveratrol exerts protective effects against HIE by enhancing oxygen supply to the brain. Resveratrol administration could be a promising approach for preventing neonatal HIE.

丸ごとの生きた組織や細胞の形態，機能，動態を計測・イメージングする多種多様な光学技術が生み出され，生物学・医学分野への応用が進められている．これらの多くの技術の基本となるのが，光の吸収や光の散乱等の光と生体組織の相互作用を考える生体組織光学（Tissue Optics）である．本稿では，生体組織光学に基づく拡散反射スペクトル解析を利用した生理機能の計測・イメージング法について，著者らの研究結果の一端について述べる．

Background: Intraoperative monitoring plays a crucial role in reducing complications during neurosurgical procedures. However, effective methods to detect brain tissue viability changes due to blood flow alterations remain unsolved. Electrophysiological techniques, such as motor evoked potentials (MEPs), and fluorescent angiography using indocyanine green, are the primary methods for intraoperative assessment. Real-time intraoperative monitoring is essential for ensuring safe neurosurgical interventions. This study aims to develop a non-contact imaging system for brain tissue surface tissue oxygen saturation (StO2) using red-green-blue (RGB) imaging based on diffuse reflectance spectroscopy. Methods: Twelve patients with cerebrovascular diseases who underwent craniotomy were included. Six patients had Moyamoya disease, while the remaining six had unruptured cerebral aneurysms. StO2 was monitored in all patients using an RGB camera during surgery. Results: In Moyamoya disease cases, superficial temporal artery (STA)-middle cerebral artery bypass and encephalo-myo-synangiosis were performed. A significant increase in StO2 was observed after STA release, correlating with cerebral hyperperfusion syndrome as evaluated by ¹⁵O-Positron Emission Tomography scans 1 day post-surgery. In cerebral aneurysm cases, StO2 alterations were noted during internal carotid artery temporary occlusion, potentially impacting MEP outcomes. The effects of various intraoperative parameters on StO2 were evaluated. Conclusion: Real-time monitoring of StO2 using a highly versatile RGB camera mounted on the side scope of any surgical microscope, regardless of model, is a promising approach for enhancing the safety and efficacy of neurosurgical interventions. By capturing real-time changes in tissue oxygenation, this method may aid in predicting postoperative complications and preventing ischemic events.

The aim of this study is to validate an approach to monitor the spatial and temporal hemodynamics of intraperitoneal organs using a commercially available laparoscopic system. The approach to create a spatial map of tissue oxygen saturation (StO₂) and total hemoglobin concentration (C _HbT) is based on a multiple regression model using Monte Carlo simulation of light transport in tissues to specify relationships between RGB values, oxygenated hemoglobin concentration, and deoxygenated hemoglobin concentration. Experiments with an optical phantom are performed to confirm the ability of the approach to detect changes in StO₂ and C _HbT under different working distances of the endoscope that may occur during actual surgery. In vivo experiments in rats confirm that the proposed approach can quantitatively monitor changes in StO₂ and C _HbT induced in the small intestine, liver, and cecum. The proposed approach has the potential as a tool for monitoring intraperitoneal organs in real time during laparoscopy.

Blood oxygen saturation (SpO2) is a crucial vital sign routinely monitored in medical settings. Traditional methods require dedicated contact sensors, limiting accessibility and comfort. This study presents a deep learning framework for contactless SpO2 measurement using an off-the-shelf camera, addressing challenges related to lighting variations and skin tone diversity. We conducted two large-scale studies with diverse participants and evaluated our method against traditional signal processing approaches in intra- and inter-dataset scenarios. Our approach demonstrated consistent accuracy across demographic groups, highlighting the feasibility of camera-based SpO2 monitoring as a scalable and non-invasive tool for remote health assessment.

As one of the most important and common forms of injury worldwide, burns can be caused by heat, chemicals, electricity, and friction. This injury is characterized by prolonged hospitalization, disfigurement, disability, and social rejection. Burns occur more frequently in the least developed and developing countries than in developed countries.^1,2 Based on tissue involvement, burns are classified into four degrees. First-degree burns (superficial burns) affect only the epidermis. Second-degree burns also affect the dermis and are further subdivided into superficial dermal burns (SDBs) affecting the epidermis and a small portion of the dermis and deep dermal burns (DDBs) affecting the epidermis and the full thickness of the dermis. Third-degree burns, or deep burns (DBs), result in complete loss of the dermis and necrosis requiring surgical removal.^{3 – 5}

In the past decade, signature clinical neuropathology of blast-induced traumatic brain injury has been under intense debate, but interface astroglial scarring (IAS) seems to be convincing. In this study, we examined whether IAS could be replicated in the rat brain exposed to a laser-induced shock wave(s) (LISW[s]), a tool that can produce a pure shock wave (primary mechanism) without dynamic pressure (tertiary mechanism). Under certain conditions, we observed astroglial scarring in the subpial glial plate (SGP), gray-white matter junctions (GM-WM), ventricular wall (VW), and regions surrounding cortical blood vessels, accurately reproducing clinical IAS. We also observed shock wave impulse-dependent meningeal damage (dural microhemorrhage) in vivo by transcranial near-infrared (NIR) reflectance imaging. Importantly, there were significant correlations between the degree of dural microhemorrhage and the extent of astroglial scarring more than 7 days post-exposure, suggesting an association of meningeal damage with astroglial scarring. The results demonstrated that the primary mechanism alone caused the IAS and meningeal damage, both of which are attributable to acoustic impedance mismatching at multi-layered tissue boundaries. The time course of glial fibrillary acidic protein (GFAP) immunoreactivity depended not only on the LISW conditions but also on the regions. In the SGP, significant increases in GFAP immunoreactivity were observed at 3 days post-exposure, whereas in the GM-WM and VW, GFAP immunoreactivity was not significantly increased before 28 days post-exposure, suggesting different pathological mechanisms. With the high-impulse single exposure or the multiple exposure (low impulse), fibrotic reaction or fibrotic scar formation was observed, in addition to astroglial scarring, in the cortical surface region. Although there are some limitations, this seems to be the first report on the shock-wave-induced IAS rodent model. The model may be useful to explore potential therapeutic approaches for IAS.

Burns are one of the most serious, dangerous, and unpredictable forms of trauma. In the management and treatment of burns patients, assessment of burn depth is crucial. Clinicians typically classify burns according to depth as superficial burns, superficial dermal burns (SDBs), deep dermal burns (DDBs), and deep burns (DBs).¹ Superficial burns affect only the superficial layer of the epidermis² and so are typically painful, but they heal without scarring and require no special care.³ SDBs are also associated with the epidermal layer, but are more painful, involving blister formation, weeping, and scar tissue. SDBs are very susceptible to infection and therefore require special treatment and care to prevent infection, but do not require surgery.^3,4 DDBs, also known as deep partial-thickness burns, involve the epidermis and a portion of the dermis, extending 2 to 3 mm into the deep dermis.⁴ While less painful, DDBs form more scar tissue. Special care is needed, and surgery may be required.³ DBs, also known as full-thickness burns, involve all layers of the epidermis and dermis, resulting in little to no pain due to massive nerve damage. Large areas of skin grafting and special care are required.³