Read by QxMD icon Read

Blood Oxygenation Level Dependent

Richard Baumgartner, William Cho, Alexandre Coimbra, Christopher Chen, Zaiqi Wang, Arie Struyk, Narayanaswamy Venketasubramanian, May Low, Cindy Gargano, Fuqiang Zhao, Donald Williams, Torsten Reese, Stephanie Seah, Dai Feng, Sonya Apreleva, Esben Petersen, Jeffrey L Evelhoch
PURPOSE: To present the testretest and contrast dose effect results of cerebral blood volume (CBV) functional MRI (fMRI) in healthy human volunteers using ferumoxytol (Feraheme), an ultrasmall-superparamagnetic iron oxide (USPIO) nanoparticle. MATERIALS AND METHODS: This was an open-label, two-period, fixed-sequence study in healthy young volunteers. In eight subjects, using a 3 Tesla field strength system, blood oxygen level dependent (BOLD) and CBV fMRI were acquired in response to a visual black-and-white checkboard stimulation paradigm using an escalating ferumoxytol dose design (250, 350, and 510 mg iron)...
October 24, 2016: Journal of Magnetic Resonance Imaging: JMRI
Anusha Mishra, James P Reynolds, Yang Chen, Alexander V Gourine, Dmitri A Rusakov, David Attwell
Active neurons increase their energy supply by dilating nearby arterioles and capillaries. This neurovascular coupling underlies blood oxygen level-dependent functional imaging signals, but its mechanism is controversial. Canonically, neurons release glutamate to activate metabotropic glutamate receptor 5 (mGluR5) on astrocytes, evoking Ca(2+) release from internal stores, activating phospholipase A2 and generating vasodilatory arachidonic acid derivatives. However, adult astrocytes lack mGluR5, and knockout of the inositol 1,4,5-trisphosphate receptors that release Ca(2+) from stores does not affect neurovascular coupling...
October 24, 2016: Nature Neuroscience
Jean-Louis Vincent, Marc Leone
Distributive shock is associated with decreased systemic vascular resistance and altered oxygen extraction. Septic shock is the most frequent form of distributive shock. In shock states, duration of hypotension is associated with poor outcomes. The speed at which treatment to restore adequate perfusion pressure is initiated is, therefore, important to improve survival. Areas covered: This review presents an overview of the literature related to the management of vasopressor-dependent distributive shock, and in particular the relationship between arterial pressure and organ perfusion and function...
October 24, 2016: Expert Review of Anti-infective Therapy
Jaakko Paasonen, Raimo A Salo, Joanna K Huttunen, Olli Gröhn
PURPOSE: Anesthesia is a major confounding factor in functional MRI (fMRI) experiments attributed to its effects on brain function. Recent evidence suggests that parameters obtained with resting-state fMRI (rs-fMRI) are coupled with anesthetic depth. Therefore, we investigated whether parameters obtained with rs-fMRI, such as functional connectivity (FC), are also directly related to blood-oxygen-level-dependent (BOLD) responses. METHODS: A simple rs-fMRI protocol was implemented in a pharmacological fMRI study to evaluate the coupling between hemodynamic responses and FC under five anesthetics (α-chloralose, isoflurane, medetomidine, thiobutabarbital, and urethane)...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Mònica Giménez, Andrés Guinea-Izquierdo, Victoria Villalta-Gil, Ignacio Martínez-Zalacaín, Cinto Segalàs, Marta Subirà, Eva Real, Jesús Pujol, Ben J Harrison, Josep Maria Haro, Joao R Sato, Marcelo Q Hoexter, Narcís Cardoner, Pino Alonso, José Manuel Menchón, Carles Soriano-Mas
The extent of functional abnormalities in frontal-subcortical circuits in obsessive-compulsive disorder (OCD) is still unclear. Although neuroimaging studies, in general, and resting-state functional Magnetic Resonance Imaging (rs-fMRI), in particular, have provided relevant information regarding such alterations, rs-fMRI studies have been typically limited to the analysis of between-region functional connectivity alterations at low-frequency signal fluctuations (i.e., <0.08 Hz). Conversely, the local attributes of Blood Oxygen Level Dependent (BOLD) signal across different frequency bands have been seldom studied, although they may provide valuable information...
October 22, 2016: Brain Imaging and Behavior
Matilde M Vaghi, Petra E Vértes, Manfred G Kitzbichler, Annemieke M Apergis-Schoute, Febe E van der Flier, Naomi A Fineberg, Akeem Sule, Rashid Zaman, Valerie Voon, Prantik Kundu, Edward T Bullmore, Trevor W Robbins
BACKGROUND: A recent hypothesis has suggested that core deficits in goal-directed behavior in obsessive-compulsive disorder (OCD) are caused by impaired frontostriatal function. We tested this hypothesis in OCD patients and control subjects by relating measures of goal-directed planning and cognitive flexibility to underlying resting-state functional connectivity. METHODS: Multiecho resting-state acquisition, combined with micromovement correction by blood oxygen level-dependent sensitive independent component analysis, was used to obtain in vivo measures of functional connectivity in 44 OCD patients and 43 healthy comparison subjects...
August 11, 2016: Biological Psychiatry
K Gerrit Held, Michael Jaeger, Jaro Rička, Martin Frenz, H Günhan Akarçay
Spectral optoacoustic (OA) imaging enables spatially-resolved measurement of blood oxygenation levels, based on the distinct optical absorption spectra of oxygenated and de-oxygenated blood. Wavelength-dependent optical attenuation in the bulk tissue, however, distorts the acquired OA spectrum and thus makes quantitative oxygenation measurements challenging. We demonstrate a correction for this spectral distortion without requiring a priori knowledge of the tissue optical properties, using the concept of multiple irradiation sensing: recording the OA signal amplitude of an absorbing structure (e...
June 2016: Photoacoustics
J Wu, S Dehkharghani, F Nahab, J Allen, D Qiu
BACKGROUND AND PURPOSE: Measuring cerebrovascular reactivity with the use of vasodilatory stimuli, such as acetazolamide, is useful for chronic cerebrovascular steno-occlusive disease. The purpose of this study was to evaluate the effects of acetazolamide on the assessment of hemodynamic impairment and functional connectivity by using noninvasive resting-state blood oxygen level-dependent MR imaging. MATERIALS AND METHODS: A 20-minute resting-state blood oxygen level-dependent MR imaging scan was acquired with infusion of acetazolamide starting at 5 minutes after scan initiation...
October 6, 2016: AJNR. American Journal of Neuroradiology
Theodore F Towse, Christopher P Elder, Emily C Bush, Samuel W Klockenkemper, Jared T Bullock, Richard D Dortch, Bruce M Damon
Muscle blood oxygenation-level dependent (BOLD) contrast is greater in magnitude and potentially more influenced by extravascular BOLD mechanisms at 7 T than it is at lower field strengths. Muscle BOLD imaging of muscle contractions at 7 T could, therefore, provide greater or different contrast than at 3 T. The purpose of this study was to evaluate the feasibility of using BOLD imaging at 7 T to assess the physiological responses to in vivo muscle contractions. Thirteen subjects (four females) performed a series of isometric contractions of the calf muscles while being scanned in a Philips Achieva 7 T human imager...
October 18, 2016: NMR in Biomedicine
Ursula F Bailer, Julie C Price, Carolyn C Meltzer, Angela Wagner, Chester A Mathis, Anthony Gamst, Walter H Kaye
OBJECTIVE: Individuals with anorexia nervosa (AN) have anxious and inhibited temperaments with high concern for consequences. Studies using either positron emission tomography (PET) or functional magnetic resonance imaging (fMRI) suggest involvement of the middle and dorsal caudate (DC) in individuals recovered (REC) from AN. For example, dopamine (DA) D2/D3 receptor binding in the middle caudate and DC was associated with anxiety and harm avoidance, and blood-oxygen-level-dependent (BOLD) response in the DC was positively related to trait anxiety...
October 18, 2016: International Journal of Eating Disorders
J C Pang, P A Robinson, K M Aquino, N Vasan
The effects of astrocytic dynamics on the blood oxygen-level dependent (BOLD) response are modeled. The dynamics are represented via an astrocytic response function that approximates the effects of astrocytic activity, including delay between neural activity and hemodynamic response. The astrocytic response function is incorporated into a spatiotemporal hemodynamic model to predict the BOLD response measured using functional magnetic resonance imaging (fMRI). Adding astrocytic dynamics is shown to significantly improve the ability of the model to robustly reproduce the spatiotemporal properties of the experimental data such as characteristic frequency and time-to-peak...
October 14, 2016: NeuroImage
Guangyong Chen, Yangdong Han, Wang He, Feng Liang
In the present study, we evaluated the protective effects of amentoflavone (AMF) against high-fat (HF) diet-induced metabolic dysfunction and focused on the influence of AMF on adipogenic differentiation during 3T3-L1 adipocyte differentiation. For this purpose, male Wistar rats were fed a HF diet or a HF diet with AMF (10 or 50 mg/kg). We found that AMF protected against HF diet-induced metabolic dysfunction in a dose-dependent manner, as evidenced by a decrease in the fasting blood glucose levels, fasting insulin levels and the homeostatic model assessment-insulin resistance index (HOMA‑IR), as well as by a decrease in the glucose level, as shown by the intraperitoneal glucose tolerance test and intraperitoneal insulin tolerance test...
October 14, 2016: International Journal of Molecular Medicine
Renee E Shimizu, Allan D Wu, Barbara J Knowlton
Effective learning results not only in improved performance on a practiced task, but also in the ability to transfer the acquired knowledge to novel, similar tasks. Using a modified serial reaction time (RT) task, the authors examined the ability to transfer to novel sequences after practicing sequences in a repetitive order versus a nonrepeating interleaved order. Interleaved practice resulted in better performance on new sequences than repetitive practice. In a second study, participants practiced interleaved sequences in a functional MRI (fMRI) scanner and received a transfer test of novel sequences...
October 17, 2016: Behavioral Neuroscience
Shunichi Suzuki, Eduardo Enrique Castrillon-Watanabe, Taro Arima, Yoshimasa Kitagawa, Peter Svensson
BACKGROUND: Myofascial pain associated with temporomandibular disorders has often been linked to pathological muscle hyperactivity. As a result, localized disturbances of intramuscular blood flow could lead to a lower level of oxygen distribution, hypoxia and microcirculatory changes. AIM: To assess hemodynamic changes in the masseter muscle during sustained elevated muscle activity (SEMA). MATERIALS AND METHODS: Sixteen healthy participants performed thirty 1-minute bouts of SEMA with intervals of 1-minute "rest" periods between the bouts on a bite force transducer device...
October 15, 2016: Journal of Oral Rehabilitation
Benedikt Wiestler, Anne Kluge, Mathias Lukas, Jens Gempt, Florian Ringel, Jürgen Schlegel, Bernhard Meyer, Claus Zimmer, Stefan Förster, Thomas Pyka, Christine Preibisch
Non-invasive, imaging-based examination of glioma biology has received increasing attention in the past couple of years. To this end, the development and refinement of novel MRI techniques, reflecting underlying oncogenic processes such as hypoxia or angiogenesis, has greatly benefitted this research area. We have recently established a novel BOLD (blood oxygenation level dependent) based MRI method for the measurement of relative oxygen extraction fraction (rOEF) in glioma patients. In a set of 37 patients with newly diagnosed glioma, we assessed the performance of a machine learning model based on multiple MRI modalities including rOEF and perfusion imaging to predict WHO grade...
October 14, 2016: Scientific Reports
Anna Nigri, Eleonora Catricalà, Stefania Ferraro, Maria Grazia Bruzzone, Ludovico D'Incerti, Davide Sattin, Davide Rossi Sebastiano, Silvana Franceschetti, Giorgio Marotta, Riccardo Benti, Matilde Leonardi, Stefano F Cappa
There is a growing interest in the use of functional imaging to assess brain activity in the absence of behavioural responses in patients with disorders of consciousness (DOC). In the present study, we applied a hierarchical auditory stimulation paradigm to functional magnetic resonance (fMRI) in a group of long-term DOC adult patients. Brain response to pairs of pseudowords, of unrelated words and of semantically related words, i.e. stimuli differing in lexical status (words vs. pseudowords) and semantic relatedness (related vs...
October 13, 2016: Brain Imaging and Behavior
M J Paldino, F Golriz, M L Chapieski, W Zhang, Z D Chu
BACKGROUND AND PURPOSE: The biologic basis for intelligence rests to a large degree on the capacity for efficient integration of information across the cerebral network. We aimed to measure the relationship between network architecture and intelligence in the pediatric, epileptic brain. MATERIALS AND METHODS: Patients were retrospectively identified with the following: 1) focal epilepsy; 2) brain MR imaging at 3T, including resting-state functional MR imaging; and 3) full-scale intelligence quotient measured by a pediatric neuropsychologist...
October 13, 2016: AJNR. American Journal of Neuroradiology
Peipei Zhang, Kohsuke Tsuchiya, Takeshi Kinoshita, Hiroko Kushiyama, Sofya Suidasari, Mizuki Hatakeyama, Hisanori Imura, Norihisa Kato, Takashi Suda
Vitamin B6 includes six water-soluble vitamers: pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), and their phosphorylated forms. Pyridoxal 5'-phosphate (PLP) is an important cofactor for many metabolic enzymes. Several lines of evidence demonstrate that blood levels of PLP are significantly lower in patients with inflammation than in control subjects, and that vitamin B6 has anti-inflammatory effects, with therapeutic potential for a variety of inflammatory diseases. Although one of our group (NK) previously demonstrated that PL inhibits the NF-κB pathway, the molecular mechanism by which vitamin B6 suppresses inflammation is not well understood...
October 12, 2016: Journal of Biological Chemistry
Daniel P Herbst
The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design...
September 2016: Journal of Extra-corporeal Technology
Laura D Lewis, Kawin Setsompop, Bruce R Rosen, Jonathan R Polimeni
Oscillatory neural dynamics play an important role in the coordination of large-scale brain networks. High-level cognitive processes depend on dynamics evolving over hundreds of milliseconds, so measuring neural activity in this frequency range is important for cognitive neuroscience. However, current noninvasive neuroimaging methods are not able to precisely localize oscillatory neural activity above 0.2 Hz. Electroencephalography and magnetoencephalography have limited spatial resolution, whereas fMRI has limited temporal resolution because it measures vascular responses rather than directly recording neural activity...
October 11, 2016: Proceedings of the National Academy of Sciences of the United States of America
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"