Abstract To obtain a better understanding of the mechanisms underlying early changes in brain water apparent diffusion coefficient (ADC) observed cerebral ischemia, dynamic ADC and energy status were measured at postnatal day 8 or 9 neonatal rat brains after cardiac arrest using 1 H MRS/MRI 31 P MRS, respectively. The time courses MR parameters compared with extracellular space (ECS) volume fraction (α) tortuosity (λ), determined from concentration‐time profiles tetramethylammonium applied...

Amyotrophic lateral sclerosis (ALS) is a progressive untreatable neurodegenerative disorder, leading to the death of cortical and spinal motoneurons (MNs). Bone marrow-derived mesenchymal stem/stromal cells (BM-MSCs) may represent new approach slowing down progression ALS by providing neurotrophic support host MNs having an anti-inflammatory effect. We have designed prospective, nonrandomized, open-label clinical trial (phase I/IIa, EudraCT No. 2011-000362-35) assess safety efficacy...

Changes in the ability of substances to diffuse intersticial space brain are important factors pathophysiology cerebrovascular diseases. Extracellular (ECS) volume fraction α ( = ECS volume/total tissue volume), tortuosity λ 2 free diffusion coefficient/apparent coefficient), and nonspecific uptake k′) − three parameters were studied cortex subcortical white matter (WM) developing rat during anoxia. compared with rise extracellular potassium concentration ([K + ] e ), pH (pH ) shifts, anoxic...

At the nodes of Ranvier, excitable axon membranes are exposed directly to extracellular fluid. Cations accumulated and depleted in local nodal region during action potential propagation, but impact extranodal micromilieu on signal propagation still remains unclear. Brain-specific hyaluronan-binding link protein, Bral1, colocalizes forms complexes with negatively charged matrix (ECM) proteins, such as versican V2 brevican, at Ranvier myelinated white matter. The protein family, including...

Diffusion parameters of the extracellular space (ECS) are changed in many brain pathologies, disturbing synaptic as well extrasynaptic “volume” transmission, which is based on diffusion neuroactive substances ECS. Amyloid deposition, neuronal loss, and disturbed transmission considered to be main causes Alzheimer's disease dementia. We studied cerebral cortex transgenic APP23 mice, develop a pathology similar disease. The real-time tetramethylammonium (TMA) method diffusion-weighted MRI were...

Vořı́šek, Ivan and Eva Syková. Evolution of anisotropic diffusion in the developing rat corpus callosum. J. Neurophysiol. 78: 912–919, 1997. Diffusion anisotropy was investigated brain [postnatal day (P)6–29] with use ion-selective microelectrodes to measure three-dimensional distribution tetramethylammonium (TMA + ) iontophoresed into extracellular space (ECS). The parameters, ECS volume fraction α (α = volume/total tissue volume), tortuosity λ (λ 2 apparent coefficient/free coefficient),...

Already moderate alcohol consumption has detrimental long-term effects on brain function. However, how produces its potent addictive despite being a weak reinforcer is poorly understood conundrum that likely hampers the development of successful interventions to limit heavy drinking. In this translational study, we demonstrate widespread increased mean diffusivity in gray matter chronically drinking humans and rats. These alterations appear soon after initiation rats, persist into early...

Extracellular matrix (ECM) is a network of macromolecules which has two forms - perineuronal nets (PNNs) and diffuse ECM (dECM) both influence brain development, synapse formation, neuroplasticity, CNS injury progression neurodegenerative diseases. remodeling can extrasynaptic transmission, mediated by diffusion neuroactive substances in the extracellular space (ECS). In this study we analyzed how disrupted PNNs dECM diffusibility. Two months after oral treatment rats with...

To understand the structural alterations that underlie early and late changes in hippocampal diffusivity after hypoxia/ischemia (H/I), apparent diffusion coefficient of water (ADC W ) were studied 8-week-old rats H/I using diffusion-weighted magnetic resonance imaging (DW-MRI). In CA1 region, ADC analyses performed during 6 months reperfusion compared with cell number/cell-type composition, glial morphology, extracellular space (ECS) parameters obtained by real-time iontophoretic method....

Astrocytic Aquaporin 4 (AQP4) and Transient receptor potential vanilloid (TRPV4) channels form a functional complex that likely influences cell volume regulation, the development of brain edema, severity ischemic injury. However, it remains to be fully elucidated whether blocking these can serve as therapeutic approach alleviate consequences having stroke.In this study, we used in vivo magnetic resonance imaging (MRI) quantify extent lesions one day (D1) seven days (D7) after permanent...

The diffusion parameters in rat cortex were studied 3-35 days following a cortical stab wound, using diffusion-weighted MR to determine the apparent coefficient of water (ADC(W)) tissue, and real-time iontophoretic tetramethylammonium (TMA) method measure extracellular space (ECS) parameters: ECS volume fraction alpha ADC TMA(+) (ADC(TMA)). Severe astrogliosis was found close mild ipsilateral but not contralateral cortex. Chondroitin sulfate proteoglycan (CSPG) expression increased...

The structural properties of brain extracellular space (ECS) are summarised by the tortuosity (λ) and volume fraction (α). To determine if these two parameters were independent, we varied size ECS changing NaCl content to alter osmolality bathing media for rat cortical slices. Values λ α extracted from diffusion measurements using real‐time ionophoretic method with tetramethylammonium (TMA + ). In normal medium (305 mosmol kg −1 ), average value was 1.69 0.24. Reducing 150 , increased 1.86...

Abstract Tenascin‐R (TN‐R), a large extracellular glycoprotein, is an important component of the adult brain's matrix (ECM); tenascin‐C (TN‐C) expressed mainly during early development, while human natural killer 1 (HNK‐1) sulphated carbohydrate epitope that attaches to these molecules, modifying their adhesive properties. To assess influence on space (ECS) volume and geometry, we used real‐time iontophoretic method measure ECS fraction α tortuosity λ , diffusion‐weighted magnetic resonance...

Huntington's disease (HD) is an inherited neurodegenerative disorder with progressive impairment of motor, behavioral and cognitive functions. The clinical features HD are closely related to the degeneration basal ganglia, predominantly striatum. main striatal output structure, globus pallidus, strongly accumulates metalloprotein-bound iron, which was recently shown influence diffusion tensor scalar values. To test hypothesis that this effect dominates in iron-rich ganglia patients, we...

Aquaporin-4 (AQP4) is the primary cellular water channel in brain and abundantly expressed by astrocytes along blood-brain barrier brain-cerebrospinal fluid interfaces. Water transport via AQP4 contributes to activity-dependent volume changes of extracellular space (ECS), which affect solute concentrations neuronal excitability. anchored α-syntrophin (α-syn), deletion leads reduced levels perivascular subpial membranes. We used real-time iontophoretic method and/or diffusion-weighted...

The proper function of the nervous system is dependent on balance ions and water between intracellular extracellular space (ECS). It has been suggested that interaction aquaporin-4 (AQP4) transient receptor potential vaniloid isoform 4 (TRPV4) channels play a role in cell volume regulation, indirectly, ECS volume. Using real-time iontophoretic method, we studied changes diffusion parameters: fraction α (α = fraction/total tissue volume) tortuosity λ (λ2 free/apparent coefficient) mice with...

Abstract Bral2 is a link protein stabilizing the binding between lecticans and hyaluronan in perineuronal nets axonal coats (ACs) specific brain regions. Using real‐time iontophoretic method diffusion‐weighted magnetic resonance, we determined extracellular space (ECS) volume fraction ( α ), tortuosity λ apparent diffusion coefficient of water ADC W ) thalamic ventral posteromedial nucleus (VPM) sensorimotor cortex young adult (3–6 months) aged (14–20 Bral2‐deficient (Bral2 −/− mice...

Changes in the extracellular space diffusion parameters during ischemia are well known, but information about changes postischemic period is lacking. Extracellular volume fraction (alpha) and tortuosity (lambda) were determined rat somatosensory cortex using real-time iontophoretic method; diffusion-weighted magnetic resonance imaging was used to determine apparent coefficient of water. Transient induced by bilateral common carotid artery clamping for 10 or 15 mins concomitant ventilation...

Diffusion‐weighted magnetic resonance (DW‐MR) is an important diagnostic tool in Huntington disease (HD), a fatal hereditary neurodegenerative disorder. To clarify the nature of diffusivity changes HD, we compared apparent diffusion coefficient water (ADC W ) acquired by DW‐MR with extracellular space volume fraction α and tortuosity λ, measured iontophoretic method R6/2 mouse model HD wild‐type controls (WT). In anisotropic globus pallidus (GP), measurements were performed mediolateral ( x...

Abstract Functional recovery after transplantation of dopaminergic cells into the lesioned striatum is dependent on widespread diffusion transmitter released by graft. In present study, we investigated parameters extracellular space in control, 6‐hydroxydopamine‐lesioned, intrastriatally grafted, and sham‐grafted rats vivo. We used two types grafts—single macrografts or multiple micrografts. The real‐time iontophoretic tetramethylammonium method enabled us to extract three parameters: volume...