Magnetic Resonance Spectroscopy (MRS)

MRS measures metabolism in the brain or in other parts of the body including the liver, heart, prostate or breast.

Serial changes in nuclear magnetic resonance relaxation times after myocardial infarction in the rabbit: relationship to water content, severity of ischemia, and histopathology over a six-month period

To determine the serial changes in T1 and T2 relaxation times of myocardial infarction, and their relationship to observed changes in water content, regional myocardial blood flow, and histopathology, rabbits were studied at 14 time intervals ranging from 30 min to 6 months after coronary artery ligation. All values were compared to a control group. Hearts were subdivided into infarct and normal segments for measurement of blood flow, water content, and relaxation times (20-MHz spectrometer); other hearts were excised intact for histopathologic studies.

Publication Type: 
Journal Articles
Journal: 
Magn Reson Med

The alterations of magnetic resonance relaxation parameters in excised myocardial tissue during NMR spectroscopy: the effects of time, environmental exposure and TTC staining

To investigate the potential impact of air exposure, time delay and vital tissue staining on the MR relaxation parameters in normal and pathological heart tissues, myocardial samples from a canine model of myocardial infarction were subject to (a) air exposure for up to 20 hours or (b) wrapping in Parafilm for up to 20 hours; immersion in (c) full strength pathological stain consisting of triphenyl tetrazolium chloride (TTC), or (d) half strength TTC, or (e) normal saline for 30 minutes.

Publication Type: 
Journal Articles
Journal: 
Magn Reson Imaging

Functional cerebral imaging by susceptibility-contrast NMR

In vivo measurement of cerebral physiology by dynamic contrast-enhanced NMR is demonstrated. Time-resolved images of the cerebral transit of paramagnetic contrast agent were acquired using a new ultrafast NMR imaging technique and a novel mechanism of image contrast based on microscopic changes in tissue magnetic susceptibility. Global hypercapnia in dogs was used to establish the relationship between susceptibility-induced signal change and brain blood volume, and the response of gray and white matter to this microvascular stimulus was measured.

Publication Type: 
Journal Articles
Journal: 
Magn Reson Med

Relationship of changes in pH and energy status to hypoxic cell fraction and hyperthermia sensitivity

The relative concentrations of nucleotide triphosphates, creatine phosphate, inorganic phosphate, and pH have been evaluated as a function of tumor volume in a murine fibrosarcoma (FSaII) by 31P NMR spectroscopy. As the tumor volume increased from 60-1250 mm3, the ratio of phosphocreatine to inorganic phosphate systemically decreased. This decrease paralleled a decrease in the ratio of nucleotide triphosphate to inorganic phosphate in the same tumor volume range. The tumor pH as measured by 31P NMR decreased slightly with tumor growth.

Publication Type: 
Journal Articles
Journal: 
Int J Radiat Oncol Biol Phys

The aerobic brain: lactate decrease at the onset of neural activity

The metabolic events of neuronal energetics during functional activity are still partially unexplained. In particular, lactate (and not glucose) was recently proposed as the main substrate for neurons during activity. By means of proton magnetic resonance spectroscopy, lactate was reported to increase during the first minutes of prolonged stimulation, but the studies reported thus far suffered from low temporal resolution.

Publication Type: 
Journal Articles
Journal: 
Neuroscience

Polarization-enhanced NMR spectroscopy of biomolecules in frozen solution

Large dynamic nuclear polarization signal enhancements (up to a factor of 100) were obtained in the solid-state magic-angle spinning nuclear magnetic resonance (NMR) spectra of arginine and the protein T4 lysozyme in frozen glycerol-water solutions with the use of dynamic nuclear polarization. Polarization was transferred from the unpaired electrons of nitroxide free radicals to nuclear spins through microwave irradiation near the electron paramagnetic resonance frequency.

Publication Type: 
Journal Articles
Journal: 
Science

Early brain injury in the SIV-macaque model of AIDS

OBJECTIVE: To specify the type and severity of cellular damage in the central nervous system soon after infection and at later stages of disease in the SIV-macaque model of AIDS.

Publication Type: 
Journal Articles
Journal: 
AIDS

Probing structure in the polymorphic domain of the L-enantiomer of N-benzoyl-phenylalanine by means of 2D solid-state NMR spectroscopy and DFT calculations

A study of polymorphism using a range of solid-state NMR techniques is presented. We demonstrate the existence of at least six polymorphs in a sample of N-benzoyl-L-phenylalanine. We also present methodology for the characterization of the protonation state, hydrogen bonding, and molecular conformation for the polymorphs, together with results of such a characterization for one of the polymorphs present in our sample. DFT modeling is used to investigate the separate effects hydrogen bonding and molecular conformation have on the chemical shift tensor.

Publication Type: 
Journal Articles
Journal: 
J Phys Chem B

Heterogeneous data fusion for brain tumor classification

Current research in biomedical informatics involves analysis of multiple heterogeneous data sets. This includes patient demographics, clinical and pathology data, treatment history, patient outcomes as well as gene expression, DNA sequences and other information sources such as gene ontology. Analysis of these data sets could lead to better disease diagnosis, prognosis, treatment and drug discovery.

Publication Type: 
Journal Articles
Journal: 
Oncol Rep

Combining magnetic resonance spectroscopy and molecular genomics offers better accuracy in brain tumor typing and prediction of survival than either methodology alone

Recent advents in magnetic resonance spectroscopy (MRS) techniques permit subsequent microarray analysis over the entire human transcriptome in the same tissue biopsies. However, extracting information from such immense quantities of data is limited by difficulties in recognizing and evaluating the relevant patterns of apparent gene expression in the context of the existing knowledge of phenotypes by histopathology. Using a quantitative approach derived from a knowledge base of pathology findings, we present a novel methodology used to process genome-wide transcription and MRS data.

Publication Type: 
Journal Articles
Journal: 
Int J Oncol

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