Acute ischemic stroke induces magnetic resonance susceptibility signs dominated by endothelial nitric oxide synthase activation.

Purpose: Acute ischemic stroke induces deoxyhemoglobin accumulation around the ischemic region while activating endothelial nitric oxide synthase (eNOS) coupling and the subsequent release of nitric oxide (NO). Because deoxyhemoglobin is a natural NO spin trap, its interplay with NO could be prominent during acute stroke. Its interaction with NO has been shown to induce overt paramagnetic signals in vitro; our goal was to investigate whether this interplay can be detected using MRI.

Neuroimaging Spectrum at Pre-, Early, and Late Symptomatic Stages of SCA17 Mice.

Spinocerebellar ataxia (SCA) is a hereditary neurodegenerative disease. We have generated SCA17 transgenic mice bearing human TBP with 109 CAG repeats under the Purkinje cell-specific L7/pcp2 promoter. These mice recapitulate the patients' phenotypes and are suitable for the study of the SCA17 pathomechanism.

Gender interactions between vertebral bone mineral density and fat content in the elderly: Assessment using fat-water MRI.

Background: Adipose tissue is closely related to bone mass, bone quality, and bone fractures, but the connection between fat and bone is complex and gender-related. Fat-water magnetic resonance imaging (MRI) and MR spectroscopy (MRS) are very useful tools for identifying tissue fat.

Purpose: To assess gender interactions between bone mineral density (BMD), bone marrow fat, and body mass index (BMI) in the elderly using fat-water MRI and MRS.

fMRI indicates cortical activation through TRPV1 modulation during acute gouty attacks.

Gout is one of the most painful disease conditions. The central mechanism of pain processing in this condition remains elusive. Cerebral blood volume (CBV) responses are faithful correlates of brain activity changes; the application of CBV-weighted functional magnetic resonance imaging (fMRI) may shed light on the issue of interest.

Temporal assessment of vascular reactivity and functionality using MRI during postischemic proangiogenenic vascular remodeling.

Postischemic angiogenesis is an important recovery mechanism. Both arteries and veins are upregulated during angiogenesis, but eventually there are more angiogenic veins than arteries in terms of number and length. It is critical to understand how the veins are modulated after ischemia and then transitioned into angiogenic vessels during the proangiogenic stage to finally serve as a restorative strength to the injured area.

Aberrant astrocytes impair vascular reactivity in Huntington disease.

Objective: Huntington disease (HD) is an inherited neurodegenerative disease caused by the mutant huntingtin gene (mHTT), which harbors expanded CAG repeats. We previously reported that the brain vessel density is higher in mice and patients with HD than in controls. The present study determines whether vascular function is altered in HD and characterizes the underlying mechanism.

Promoted Growth of Brain Tumor by the Transplantation of Neural Stem/Progenitor Cells Facilitated by CXCL12.

The targeted migration of neural stem/progenitor cells (NSPCs) is a prerequisite for the use of stem cell therapy in the treatment of pathologies. This migration is regulated mainly by C-X-C motif chemokine 12 (CXCL12). Therefore, promotion of the migratory responses of grafted cells by upregulating CXCL12 signaling has been proposed as a strategy for improving the efficacy of such cell therapies.

White matter tracts for the trafficking of neural progenitor cells characterized by cellular MRI and immunohistology: the role of CXCL12/CXCR4 signaling.

White matter tracts are important for the trafficking of neural progenitor cells (NPCs) in both normal and pathological conditions, but the underlying mechanism is not clear. The directionality of white matter is advantageous for molecules or cells to distribute over a long distance, but this feature is unlikely solely responsible for efficient migration. The present study hypothesizes that the efficient migration of NPCs into white matter is under the influences of neurochemical attraction—CXCL12/CXCR4 signaling, a major mechanism underlying the targeted migration of NPCs.

Negative cerebral blood volume fMRI response coupled with Ca²⁺-dependent brain activity in a dopaminergic road map of nociception.

Decreased cerebral blood volume/flow (CBV/CBF) contributes to negative blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) signals. But it is still strongly debated whether these negative BOLD or CBV/CBF signals are indicative of decreased or increased neuronal activity. The fidelity of Ca(2+) signals in reflecting neuronal excitation is well documented.

High-resolution structural and functional assessments of cerebral microvasculature using 3D Gas ΔR2*-mMRA.

The ability to evaluate the cerebral microvascular structure and function is crucial for investigating pathological processes in brain disorders. Previous angiographic methods based on blood oxygen level-dependent (BOLD) contrast offer appropriate visualization of the cerebral vasculature, but these methods remain to be optimized in order to extract more comprehensive information. This study aimed to integrate the advantages of BOLD MRI in both structural and functional vascular assessments.

In vivo evidence of increased nNOS activity in acute MPTP neurotoxicity: a functional pharmacological MRI study.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin commonly used to produce an animal model of Parkinson's disease. Previous studies have suggested a critical role for neuronal nitric oxide (NO) synthase- (nNOS-) derived NO in the pathogenesis of MPTP. However, NO activity is difficult to assess in vivo due to its extremely short biological half-life, and so in vivo evidence of NO involvement in MPTP neurotoxicity remains scarce.

Neurovascular abnormalities in humans and mice with Huntington's disease.

Cerebral microvascular aberrations have recently become recognized as a source of pathologies in neurodegenerative disorders, but this concept has not been fully examined with respect to Huntington's disease (HD). A novel in vivo technique, three-dimensional microscopic magnetic resonance angiography (μMRA), allows visualization of the neurovascular system in exquisite detail and provides quantitative structural and functional information. This technique was applied in the present study, in parallel with immunohistological analysis and behavioral assessment, to a well-characterized mouse model of HD (R6/2).

Neurovascular abnormalities in brain disorders: highlights with angiogenesis and magnetic resonance imaging studies.

The coupling between neuronal activity and vascular responses is controlled by the neurovascular unit (NVU), which comprises multiple cell types. Many different types of dysfunction in these cells may impair the proper control of vascular responses by the NVU. Magnetic resonance imaging, which is the most powerful tool available to investigate neurovascular structures or functions, will be discussed in the present article in relation to its applications and discoveries.

Hyperglycemia exacerbates intracerebral hemorrhage via the downregulation of aquaporin-4: temporal assessment with magnetic resonance imaging.

Background And Purpose: Intracerebral hemorrhage (ICH) is associated with high mortality and neurological deficits, and concurrent hyperglycemia usually worsens clinical outcomes. Aquaporin-4 (AQP-4) is important in cerebral water movement. Our aim was to investigate the role of AQP-4 in hyperglycemic ICH.

Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles.

In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2 -RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities.

Simple SPION incubation as an efficient intracellular labeling method for tracking neural progenitor cells using MRI.

Cellular magnetic resonance imaging (MRI) has been well-established for tracking neural progenitor cells (NPC). Superparamagnetic iron oxide nanoparticles (SPIONs) approved for clinical application are the most common agents used for labeling. Conventionally, transfection agents (TAs) were added with SPIONs to facilitate cell labeling because SPIONs in the native unmodified form were deemed inefficient for intracellular labeling.

Dopaminergic imaging of nonmotor manifestations in a rat model of Parkinson's disease by fMRI.

Nonmotor manifestations determine the life quality of patients with Parkinson's disease (PD). Identification of the nonmotor symptoms in PD as definite changes will represent a milestone in its diagnosis. Outcome measures that characterize nonmotor manifestations with specificity for dopaminergic deficiency are essential to that goal.

MR phase imaging: sensitive and contrast-enhancing visualization in cellular imaging.

The successful translation of stem-cell therapies requires a detailed understanding of the fate of transplanted cells. Magnetic resonance imaging (MRI) has provided a noninvasive means of imaging cell dynamics in vivo by prelabeling cell with T(2) shortening iron oxide particles. However, this approach suffers from a gradual loss of sensitivity since active cell mitosis could decrease the cellular contrast agent (CA) concentration below detection level.

A lifespan MRI evaluation of ventricular enlargement in normal aging mice.

Ventricular enlargement has been proposed as a structural biomarker for the progression of Alzheimer's disease (AD). This biomarker, established in human patients, needs to be translated to animals to facilitate drug development for the disease. However, ventricular enlargement is not exclusive to AD, since the ventricle size increases during normal aging.

A new scenario for negative functional magnetic resonance imaging signals: endogenous neurotransmission.

Functional magnetic resonance imaging (fMRI) has revolutionized investigations of brain functions. Increases in fMRI signals are usually correlated with neuronal activation, but diverse explanations have been proposed for negative fMRI responses, including decreases in neuronal activity, the vascular-steal effect, and large increases in oxygen consumption. These possible scenarios, although encompassing a wide range of potential neurovascular responses, cannot yet be used to interpret certain types of negative fMRI signals.

Whole-brain functional magnetic resonance imaging mapping of acute nociceptive responses induced by formalin in rats using atlas registration-based event-related analysis.

Nociceptive neuronal activation in subcortical regions has not been well investigated in functional magnetic resonance imaging (fMRI) studies. The present report aimed to use the blood oxygenation level-dependent (BOLD) fMRI technique to map nociceptive responses in both subcortical and cortical regions by employing a refined data processing method, the atlas registration-based event-related (ARBER) analysis technique. During fMRI acquisition, 5% formalin (50 mul) was injected into the left hindpaw to induce nociception.

Neuroaxonal ion dyshomeostasis of the normal-appearing corpus callosum in experimental autoimmune encephalomyelitis.

Atrophy of the corpus callosum (CC) is a well-documented observation in clinically definite multiple sclerosis (MS) patients. One recent hypothesis for the neurodegeneration that occurs in MS is that ion dyshomeostasis leads to neuroaxonal damage. To examine whether ion dyshomeostasis occurs in the CC during MS onset, experimental autoimmune encephalomyelitis (EAE) was utilized as an animal MS model to induce autoimmunity-mediated responses.

Neuronal dysfunction of a long projecting multisynaptic pathway in response to methamphetamine using manganese-enhanced MRI.

Rationale: Manganese (Mn2+)-enhanced magnetic resonance imaging (MEMRI) is an emerging in vivo MR approach for pharmacological research. One new application of MEMRI in this area is to characterize functional changes of a specific neural circuit that is essential to the central effects of a drug challenge.

Objectives: To develop and validate such use of MEMRI in neuropharmacology, the current study applied MEMRI to visualize functional changes within a multisynaptic pathway originating from fasciculus retroflexus (FR) that is central to a commonly abused psychostimulant, methamphetamine (MA).

Organization of immune-responsive medullary projections to the bed nucleus of the stria terminalis, central amygdala, and paraventricular nucleus of the hypothalamus: evidence for parallel viscerosensory pathways in the rat brain.

Immune-responsive neurons in the brainstem, primarily in the nucleus of the solitary tract (NTS) and ventrolateral medulla (VLM), contribute to a significant drive on forebrain nuclei responsible for brain-mediated host defense responses. The current study investigated the relative contribution of brainstem-derived ascending pathways to forebrain immune-responsive nuclei in the rat by means of retrograde tract tracing and c-Fos immunohistochemistry. Fluorogold was iontophoresed into the bed nucleus of stria terminalis (BST), central nucleus of the amygdala (CEA), paraventricular nucleus of the hypothalamus (PVN), and the pontine lateral parabrachial nucleus (PBL; an important component of ascending viscerosensensory pathways) followed 2 weeks later by intraperitoneal injection of lipopolysaccharide (LPS, 0.

Pre- and post-training infusion of prazosin into the bed nucleus of the stria terminalis impaired acquisition and retention in a Morris water maze task.

The bed nucleus of the stria terminalis (BNST) is interconnected with the amygdala that is implicated in memory modulation. In view of the innervation of this structure by the hippocampus and brain stem noradrenergic nuclei, this study examined the role of BNST noradrenergic activity in acquisition, formation and expression of spatial memory. Male Wistar rats with indwelling cannulae in the BNST were trained on a spatial navigation task in the Morris water maze.