Correlation of zero echo time functional MRI with neuronal activity in rats.

Zero echo time (zero-TE) pulse sequences provide a quiet and artifact-free alternative to conventional functional magnetic resonance imaging (fMRI) pulse sequences. The fast readouts (<1 ms) utilized in zero-TE fMRI produce an image contrast with negligible contributions from blood oxygenation level-dependent (BOLD) mechanisms, yet the zero-TE contrast is highly sensitive to brain function. However, the precise relationship between the zero-TE contrast and neuronal activity has not been determined.

Controlled synthesis and characterization of porous silicon nanoparticles for dynamic nuclear polarization.

Si nanoparticles (NPs) have been actively developed as a hyperpolarized magnetic resonance imaging (MRI) contrast agent with an imaging window close to one hour. However, the progress in the development of NPs has been hampered by the incomplete understanding of their structural properties that correspond to efficient hyperpolarization buildup and long polarization decays. In this work we study dynamic nuclear polarization (DNP) of single crystal porous Si (PSi) NPs with defined doping densities ranging from nominally undoped to highly doped with boron or phosphorus.

Simultaneous fMRI and metabolic MRS of hyperpolarized [1-C]pyruvate during nicotine stimulus in rat.

Functional MRI (fMRI) and MRS (fMRS) can be used to noninvasively map cerebral activation and metabolism. Recently, hyperpolarized C spectroscopy and metabolic imaging have provided an alternative approach to assess metabolism. In this study, we combined H fMRI and hyperpolarized [1-C]pyruvate MRS to compare cerebral blood oxygenation level-dependent (BOLD) response and real-time cerebral metabolism, as assessed with lactate and bicarbonate labelling, during nicotine stimulation.

Changes in liver metabolic pathways demonstrate efficacy of the combined dietary and microbial therapeutic intervention in MASLD mouse model.

Objective: Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is the most prevalent liver disease globally, yet no therapies are approved. The effects of Escherichia coli Nissle 1917 expressing aldafermin, an engineered analog of the intestinal hormone FGF19, in combination with dietary change were investigated as a potential treatment for MASLD.

Methods: MASLD was induced in C57BL/6J male mice by American lifestyle-induced obesity syndrome diet and then switched to a standard chow diet for seven weeks.

Redox Properties and in Vivo Magnetic Resonance Imaging of Cyclodextrin-Polynitroxides Contrast Agents.

This paper reports the synthesis, characterization and in vivo application of water-soluble supramolecular contrast agents (Mw: 5-5.6 kDa) for MRI obtained from β-cyclodextrin functionalized with different kinds of nitroxide radicals, both with piperidine structure (CD2 and CD3) and with pyrrolidine structure (CD4 and CD5). As to the stability of the radicals in presence of ascorbic acid, CD4 and CD5 have low second order kinetic constants (≤0.

Axon fiber orientation as the source of T relaxation anisotropy in white matter: A study on corpus callosum in vivo and ex vivo.

Purpose: Recent studies indicate that T in white matter (WM) is influenced by fiber orientation in B . The purpose of the study was to investigate the interrelationships between axon fiber orientation in corpus callosum (CC) and T relaxation time in humans in vivo as well as in rat brain ex vivo.

Methods: Volunteers were scanned for relaxometric and diffusion MRI at 3 T and 7 T.

Associations of altered hepatic gene expression in American lifestyle-induced obesity syndrome diet-fed mice with metabolic changes during NAFLD development and progression.

Non-alcoholic fatty liver disease (NAFLD) pathogenesis remains poorly understood due to the complex metabolic and inflammatory changes in the liver. This study aimed to elucidate hepatic events related to inflammation and lipid metabolism and their linkage with metabolic alterations during NAFLD in American lifestyle-induced obesity syndrome (ALIOS) diet-fed mice. Forty-eight C57BL/6J male mice were fed with ALIOS diet (n=24) or control chow diet (n=24) for 8, 12, and 16 weeks.

Use of paclitaxel-coated balloons in clinical setting is not associated with increased mortality compared with plain balloon angioplasty in femoropopliteal lesions.

Objective: To investigate mortality and causes of death associated with the use of paclitaxel-coated balloon (PCB) compared with plain balloon (PB) angioplasty in the treatment of femoropopliteal artery lesions in real-world clinical setting.

Methods: This retrospective, single-center study included patients who underwent percutaneous femoropopliteal artery angioplasty without stenting between years 2014 and 2020. Patients were stratified into PCB and PB groups according to the index procedure.

Sensitive, Efficient and Portable Analysis of Molecular Exchange Processes by Hyperpolarized Ultrafast NMR.

Molecular exchange processes are ubiquitous in nature. Here, we introduce a method to analyze exchange processes by using low-cost, portable, single-sided NMR instruments. The inherent magnetic field inhomogeneity of the single-sided instruments is exploited to achieve diffusion contrast of exchange sites and spatial encoding of 2D data.

Magnetically Assisted Drug Delivery of Topical Eye Drops Maintains Retinal Function In Vivo in Mice.

Barded-Biedl syndrome (BBS) is a rare genetic disorder with an unmet medical need for retinal degeneration. Small-molecule drugs were previously identified to slow down the apoptosis of photoreceptors in BBS mouse models. Clinical translation was not practical due to the necessity of repetitive invasive intravitreal injections for pediatric populations.

Metabolism of hyperpolarised [1- C]pyruvate in awake and anaesthetised rat brains.

The use of hyperpolarised C pyruvate for nononcological neurological applications has not been widespread so far, possibly due to delivery issues limiting the visibility of metabolites. First proof-of-concept results have indicated that metabolism can be detected in human brain, and this may supersede the results obtained in preclinical settings. One major difference between the experimental setups is that preclinical MRI/MRS routinely uses anaesthesia, which alters both haemodynamics and metabolism.

Data-Driven Regularization Parameter Selection in Dynamic MRI.

In dynamic MRI, sufficient temporal resolution can often only be obtained using imaging protocols which produce undersampled data for each image in the time series. This has led to the popularity of compressed sensing (CS) based reconstructions. One problem in CS approaches is determining the regularization parameters, which control the balance between data fidelity and regularization.

Inflammatory reaction in the retina after focal non-convulsive status epilepticus in mice investigated with high resolution magnetic resonance and diffusion tensor imaging.

Pathophysiological consequences of focal non-convulsive status epilepticus (fNCSE) have been difficult to demonstrate in humans. In rats fNCSE pathology has been identified in the eyes. Here we evaluated the use of high-resolution 7 T structural T-weighted magnetic resonance imaging (MRI) and 9.

Alcohol Co-Administration Changes Mephedrone-Induced Alterations of Neuronal Activity.

Mephedrone (4-MMC), despite its illegal status, is still a widely used psychoactive substance. Its effects closely mimic those of the classical stimulant drug methamphetamine (METH). Recent research suggests that unlike METH, 4-MMC is not neurotoxic on its own.

Cyclodextrin-Based Organic Radical Contrast Agents for in vivo Imaging of Gliomas.

Cyclodextrins (CDs), a class of cyclic oligosaccharides formed by α-(1,4) linked glucopyranose units, were functionalized with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) radicals to prepare water soluble supramolecular organic radical contrast agents (ORCAs) for the in vivo detection of glioma tumor in animal models. A first set of molecules (CDn1, n=6,7,8 is the number of both TEMPO and glucopyranose units) was studied by superconducting quantum interference devices (SQUID) magnetometry in order to define the role of the CD macrocycle on the effective magnetic moment (μ ). The μ value increased from 3.

Assessment of the Relaxation-Enhancing Properties of a Nitroxide-Based Contrast Agent TEEPO-Glc with Magnetic Resonance Imaging.

Magnetic resonance imaging examinations are frequently carried out using contrast agents to improve the image quality. Practically all clinically used contrast agents are based on paramagnetic metals and lack in selectivity and specificity. A group of stable organic radicals, nitroxides, has raised interest as new metal-free contrast agents for MRI.

Hyperpolarized MRI for Studying Tumor Metabolism.

Hyperpolarized magnetic resonance imaging (MRI) can be used to detect real-time in vivo tumor metabolism. Dissolution dynamic nuclear polarization method increases polarization of C-labeled molecules, typically [1-C]pyruvate, which can be injected into an animal during MRI scanning. Increased polarization leads to a higher observed signal, which allows for the detection and imaging of the transfer of C-label between the injected marker molecule, pyruvate, and its metabolic products, most importantly lactate.

Designed inorganic porous nanovector with controlled release and MRI features for safe administration of doxorubicin.

The inability of traditional chemotherapeutics to reach cancer tissue reduces the treatment efficacy and leads to adverse effects. A multifunctional nanovector was developed consisting of porous silicon, superparamagnetic iron oxide, calcium carbonate, doxorubicin and polyethylene glycol. The particles integrate magnetic properties with the capacity to retain drug molecules inside the pore matrix at neutral pH to facilitate drug delivery to tumor tissues.

Cu(atsm) Attenuates Neuroinflammation.

Neuroinflammation and biometal dyshomeostasis are key pathological features of several neurodegenerative diseases, including Alzheimer's disease (AD). Inflammation and biometals are linked at the molecular level through regulation of metal buffering proteins such as the metallothioneins. Even though the molecular connections between metals and inflammation have been demonstrated, little information exists on the effect of copper modulation on brain inflammation.

Loss of NRF-2 and PGC-1α genes leads to retinal pigment epithelium damage resembling dry age-related macular degeneration.

Age-related macular degeneration (AMD) is a multi-factorial disease that is the leading cause of irreversible and severe vision loss in the developed countries. It has been suggested that the pathogenesis of dry AMD involves impaired protein degradation in retinal pigment epithelial cells (RPE). RPE cells are constantly exposed to oxidative stress that may lead to the accumulation of damaged cellular proteins, DNA and lipids and evoke tissue deterioration during the aging process.

Analysis of C and C labeling in pyruvate and lactate in tumor and blood of lymphoma-bearing mice injected with C- and C-labeled pyruvate.

Measurements of hyperpolarized C label exchange between injected [1- C]pyruvate and the endogenous tumor lactate pool can give an apparent first-order rate constant for the exchange. The determination of the isotope flux, however, requires an estimate of the labeled pyruvate concentration in the tumor. This was achieved here by measurement of the tumor uptake of [1- C]pyruvate, which showed that <2% of the injected pyruvate reached the tumor site.

Behavioral and stereological characterization of Hdc KO mice: Relation to Tourette syndrome.

A premature termination codon in the human histidine decarboxylase (Hdc) gene has been identified in a family suffering from Guilles de la Tourette syndrome (GTS). In the current study we investigated if mice lacking the histamine producing enzyme HDC share the morphological and cytological phenotype with GTS patients by using magnetic resonance (MRI) and diffusion tensor imaging (DTI), unbiased stereology and immunohistochemistry. Behavior of Hdc knock-out (Hdc KO) mice was assessed in an open field test.

Analysis of heterogeneity in T2-weighted MR images can differentiate pseudoprogression from progression in glioblastoma.

Purpose: To develop an image analysis technique that distinguishes pseudoprogression from true progression by analyzing tumour heterogeneity in T2-weighted images using topological descriptors of image heterogeneity called Minkowski functionals (MFs).

Methods: Using a retrospective patient cohort (n = 50), and blinded to treatment response outcome, unsupervised feature estimation was performed to investigate MFs for the presence of outliers, potential confounders, and sensitivity to treatment response. The progression and pseudoprogression groups were then unblinded and supervised feature selection was performed using MFs, size and signal intensity features.