Publications by authors named "Akira Sumiyoshi"

Lipopolysaccharide (LPS) is a bacterial endotoxin that induces innate immune responses. The present study aimed to elucidate alterations in cerebral cortical surface morphology induced by neonatal exposure to LPS using gyrencephalic ferrets. Male ferret pups received a subcutaneous injection of LPS (500 µg/g of body weight) on Postnatal Day (P)6 and P7.

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A noninvasive method to estimate oxygenation and oxygen (O) consumption rates in mouse brain tissue based on T-weighted tissue oxygen level-dependent (TOLD) MRI was developed. The aim of the present study was to estimate the kinetics of O in tissue in order to facilitate the planning of radiation therapy. The relationship between the proton T relaxation rate and O concentrations was examined in water and corn oil samples, which are models of the aqueous and lipidic phases of cell components.

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Hemoglobin shows different contrasts on magnetic resonance imaging (MRI) depending on the iron and oxygenation states of heme. Functional brain MRI utilizes the differences in the concentrations of oxyhemoglobin and deoxyhemoglobin in cerebral blood vessels; blood clots produce strong magnetic susceptibility effects. We hypothesized that methemoglobin (MetHb)-based nanoparticles can act as MRI contrast agents because MetHb levels in red blood cells affect relaxivity and are strictly regulated to <1% in the blood.

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A method to simulate the dipole moment mode of the scanning nonlinear dielectric microscope (SNDM) has been developed. This method has been applied to the so-called [Formula: see text] dimer-adatom-stacking-fault (DAS) structure and a [Formula: see text] surface with one adatom and one restatom, which are the main motifs of the DAS structure. It has been revealed that a local upward dipole moment is observed at the adatom site, consistent with the SNDM experiments.

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Abnormalities and alterations in the glycolytic pathway in the pathology of neurodegenerative diseases and brain aging have received much attention, as clinical applications of proton-based magnetic resonance spectroscopy (MRS) have recently illuminated the elevation of lactate concentrations in the brains of patients with neurodegenerative diseases, including Alzheimer's disease. Hyperpolarized [1-C]pyruvate MRS has shown promise for neurological applications because it enables the real-time detection of glycolysis and oxidative phosphorylation flux. In studies of the mouse brain using hyperpolarized [1-C]pyruvate, there are few reports that the signal of [C]bicarbonate, a product of oxidative phosphorylation metabolized from [1-C]pyruvate, was detected using MR spectroscopic imaging (MRSI) that allows spatial mapping of metabolism, although there have been reports of [C]bicarbonate signals being detected by pulse-acquire sequences in the entire brain.

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Article Synopsis
  • Copy number variants (CNVs) are linked to psychiatric disorders and brain structure changes, but the specific gene effects within the CNV regions, like 22q11.2, are still unclear.
  • This study focuses on Tbx1, a gene in the 22q11.2 region, exploring how it influences brain volume and behaviors through a detailed analysis of Tbx1 heterozygous mice using magnetic resonance imaging.
  • Results showed decreased volumes in key brain areas associated with social behavior and learning, while some auditory regions were larger, highlighting the nuanced impacts of Tbx1 on brain structure and function.
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Adult neurogenesis confers the hippocampus with unparalleled neural plasticity, essential for intricate cognitive functions. The specific influence of sparse newborn neurons (NBNs) in modulating neural activities and subsequently steering behavior, however, remains obscure. Using an engineered NBN-tetanus toxin mouse model (NBN-TeTX), we noninvasively silenced NBNs, elucidating their crucial role in impulse inhibition and cognitive flexibility as evidenced through Morris water maze reversal learning and Go/Nogo task in operant learning.

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Nano-sized contrast agents (NCAs) hold potential for highly specific tumor contrast enhancement during magnetic resonance imaging. Given the quantity of contrast agents loaded into a single nano-carrier and the anticipated relaxation effects, the current molecular design approaches its limits. In this study, a novel molecular mechanism to augment the relaxation of NCAs is introduced and demonstrated.

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  • * In experiments on glioblastoma mice, Q0/A significantly reduced tumor growth and improved survival rates, demonstrated by increased oxidative stress specifically in the tumor and increased blood flow to the tumor.
  • * The treatment showed stronger anticancer effects compared to a previous method (menadione/ascorbate) and had no noticeable side effects, suggesting it could be a safe option for targeted glioblastoma therapy.
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Article Synopsis
  • Copy number variants (CNVs), especially those in the 22q11.2 region, are linked to psychiatric disorders and brain structure changes, but the exact relationship between specific genes and these issues isn't fully understood.
  • This study focuses on a gene within the 22q11.2 CNV, suggesting it plays a significant role in social interaction, memory, and cognitive flexibility.
  • Using brain imaging in mice with this genetic variant, researchers found reduced volumes in certain brain areas and linked these changes to difficulties in social interactions, highlighting the impact of genetic loss-of-function variants.
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Copy number variants (CNVs) are robustly associated with psychiatric disorders and their dimensions and changes in brain structures and behavior. However, as CNVs contain many genes, the precise gene-phenotype relationship remains unclear. Although various volumetric alterations in the brains of 22q11.

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Allergic asthma is a common chronic inflammatory condition associated with psychiatric comorbidities. Notably depression, correlated with adverse outcomes in asthmatic patients. Peripheral inflammation's role in depression has been shown previously.

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  • The study introduces a new approach to cancer treatment that targets cancerous mitochondria using "mitocans," specifically redox-cycling quinone/ascorbate (Q/A) pairs, which primarily harm cancer cells while sparing normal cells.
  • Eleven different Q/A combinations were tested on both cultured cancer cells and mice with tumors, leading to a significant reduction in cancer cell growth and survival without major negative effects on healthy cells.
  • The findings highlight that certain Q/A pairs, particularly benzoquinone/ascorbate, induce harmful oxidative stress in cancer cells while showing tolerable impacts on normal cells, attributed to changes in mitochondrial behavior and specific interactions within cancer cells.
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Article Synopsis
  • * It introduces StandardRat, a standardized fMRI acquisition protocol for rats that has been tested across 20 research centers to enhance data integration.
  • * The standardized protocol and processing pipeline improve the reliability of detecting functional connectivity patterns and are made publicly available to foster collaboration in the neuroimaging field.
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Objectives: To establish a CT lymphangiography method in mice via direct lymph node puncture.

Methods: We injected healthy mice (n = 8) with 50 µl of water-soluble iodine contrast agent (iomeprol; iodine concentration, 350 mg/mL) subcutaneously into the left-rear foot pad (interstitial injection) and 20 µl of the same contrast agent directly into the popliteal lymph node (direct puncture) 2 days later. Additionally, we performed interstitial MR lymphangiography on eight mice as a control group.

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Purpose: The development of magnetic resonance imaging (MRI) contrasting agents (CAs) that are safer and have a higher relaxivity than Gd(III)-based agents is a significant research topic. Herein, we propose the use of a Mn-based metal organic framework (MOF), Mn-MOF-74, characterized by a safe paramagnetic center, a coordinatively unsaturated site (CUS) for aquation, and a long rotational correlation time, endowing high relaxivity. Furthermore, biocompatibility and delivery to the tumor are generally expected for MOFs that are obtainable in the nanometer size range.

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A curcumin derivative conjugated with Gd-DO3A (Gd-DO3A-Comp.B) was synthesised as an MRI contrast agent for detecting the amyloid-β (Aβ) fibrillation process. Gd-DO3A-Comp.

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A considerable amount of data have accumulated in the last decade on the pronounced mitochondrial fatty acid oxidation (mFAO) in many types of cancer cells. As a result, mFAO was found to coexist with abnormally activated fatty acid synthesis (FAS) and the mevalonate pathway. Recent studies have demonstrated that overactivated mitochondrial β-oxidation may aggravate the impaired mitochondrial redox state and vice versa.

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Article Synopsis
  • Glioblastoma is a highly aggressive brain tumor with an imbalance in redox states, making its treatment challenging due to its unique oxidative nature.
  • The study investigates a new treatment approach using a redox-active drug combination (menadione/ascorbate) to specifically target glioblastoma in both animal models and cell cultures, leading to reduced tumor growth and improved survival without harmful side effects.
  • Results showed that the treatment increased oxidative stress and disrupted the cancer cells' functionality while selectively harming glioblastoma cells, as opposed to normal cells, highlighting the potential for targeted therapies in cancer treatment.
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Article Synopsis
  • - The study introduces a new drug combo, menadione/ascorbate (M/A), aimed at selectively targeting glioblastoma, comparing its effectiveness to the standard chemotherapy, temozolomide (TMZ).
  • - Experiments on glioblastoma mice showed that M/A treatment slowed tumor growth and improved survival rates without the side effects common with TMZ, though M/A's tumor shrinkage was not as significant.
  • - M/A was found to selectively harm glioblastoma cells by increasing mitochondrial superoxide production while leaving normal cells unharmed, suggesting a potential use alongside surgery and traditional treatments for better patient outcomes.
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Copy number variants (CNVs) have provided a reliable entry point to identify the structural correlates of atypical cognitive development. Hemizygous deletion of human chromosome 22q11.2 is associated with impaired cognitive function; however, the mechanisms by which the CNVs contribute to cognitive deficits via diverse structural alterations in the brain remain unclear.

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Glucose sensors for NMR relaxometry and magnetic resonance imaging (MRI) can be used for the direct measurement of glucose in turbid biological specimens. Here, we proposed a magnetic glucose sensor based on superparamagnetic iron oxide (SPIO) nanoparticles conjugated to a mannopyranoside derivative and concanavalin A (ConA). The binding of mannopyranoside groups to ConA produced a nanoparticle cluster that was dissociated by competitive binding of glucose to ConA, resulting in changes in the transverse relaxation time (T) in a glucose-dependent manner.

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Magnetic Resonance Imaging (MRI) contrast agents with rapid renal excretion that do not penetrate the blood brain barrier (BBB) and blood cerebrospinal fluid barrier (BCFB) are preferred for safer and low-risk diagnosis. Gadolinium (Gd)-conjugated nanoparticles have been proposed for use as contrast agents; however, the particle size must range between 1 to 7 nm to ensure rapid renal excretion. In this study, three types of gelatin, dissolved in water at varying concentrations of 0.

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Alzheimer's disease (AD), a neurodegenerative disease, causes behavioural abnormalities such as disinhibition, impulsivity, and hyperphagia. Preclinical studies using AD model mice have investigated these phenotypes by measuring brain activity in awake, behaving mice. In this study, we monitored the behavioural alterations of impulsivity and hyperphagia in middle-aged AD model mice.

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