Abstract Accurate knowledge of the magnetic properties human blood is required for precise modeling functional and vascular flow‐related MRI. Herein are reported determinations relaxation parameters blood, employing in vitro samples that well representative situ. The envelope 1 H 2 O free‐induction decay signal magnitude during first 100 msec following a spin echo at time TE well‐ described empirically by an expression form, S ( t ) = o · exp{– R – TE) AR * }. increase as function square...

Abstract BACKGROUND: Glyphosate‐resistant (GR) weed species are now found with increasing frequency and threaten the critically important GR management system. RESULTS: The reported 31 P NMR experiments on glyphosate‐sensitive (S) glyphosate‐resistant (R) horseweed, Conyza canadensis (L.) Cronq., show significantly more accumulation of glyphosate within R biotype vacuole. CONCLUSIONS: Selective sequestration into vacuole confers observed horseweed resistance to glyphosate. This observation...

Abstract The biophysical mechanism(s) underlying diffusion‐weighted MRI contrast following brain injury remains to be elucidated. Although it is generally accepted that water apparent diffusion coefficient (ADC) decreases after injury, unknown whether this associated with a decrease in intracellular or extracellular displacement, both. To address question, 2‐[ 19 F]luoro‐2‐deoxyglucose‐6‐phosphate (2FDG‐6P) was employed as compartment‐specific marker normal and globally ischemic rat brain....

A general statistical model that can describe a rather large number of experimental results related to the structure diffusion-attenuated MR signal in biological systems is introduced. The theoretical framework relies on phenomenological introduces distribution function for tissue apparent diffusion coefficients (ADC). It shown at least two parameters--the position maxima (ADC) and width (sigma)--are needed most regions human brain. substantial width, order 36% ADC, was found practically all...

A fundamental discovery of modern human brain imaging with positron-emission tomography that the blood flow to activated regions normal increases substantially more than oxygen consumption has led a broad discussion in literature concerning possible mechanisms responsible for this phenomenon. Presently no consensus exists. It is well known delivery not only function systemic circulation. Additional roles include nutrients and other required substances tissue, waste removal, temperature...

Lolium spp., ryegrass, variants from Australia, Brazil, Chile, and Italy showing differing levels of glyphosate resistance were examined by (31)P NMR. Extents (i) (LD(50)), (ii) inhibition 5-enopyruvyl-shikimate-3-phosphate synthase (EPSPS) activity (IC(50)), (iii) translocation quantified for glyphosate-resistant (GR) glyphosate-sensitive (GS) multiflorum Lam. Chile Brazil. For comparison, LD(50) IC(50) data rigidum Gaudin also analyzed. All showed similar cellular uptake GR sequestration...

Global cardiac function has been studied in small animals with methods such as echocardiography, cine-magnetic resonance imaging (MRI), and catheterization. However, these modalities make little impact on delineation of pathophysiology at the tissue level. The advantage tagged cine-MRI technique is that twisting motion ventricle, referred to torsion, can be measured noninvasively, reflecting underlying shearing individual planes myofibrils generate wall thickening ventricular ejection. Thus...

Abstract In the brain, on a macroscopic scale, diffusion of intraneuronal constituent N ‐acetyl‐L‐aspartate (NAA) appears to be isotropic. contrast, microscopic NAA is likely highly anisotropic, with displacements perpendicular neuronal fibers being markedly hindered, and parallel less so. this report we first substantiate that local anisotropy influences in vivo by observing differing diffusivities human corpus callosum axonal fibers. We then extend our measurements large voxels within rat...

This report describes the measurement of water preexchange lifetimes and intra/extracellular content in intact, functioning mammalian brain. Intra- extracellular magnetic resonance (MR) signals from rat brain vivo were quantitatively resolved longitudinal relaxation domain following administration an MR agent into space. The estimated intracellular fraction was 81% +/- 8%, intra- to exchange rate constant 1.81 0.89 s(-1) (mean SD, N = 9), corresponding lifetime approximately 550 ms. These...

Quantitative characterization of the intracellular water (1)H MR signal from cultured cells will provide critical biophysical insight into tissues in vivo. Microbeads a robust immobilization substrate for many mammalian cell lines that adhere to surfaces and also sufficient density observation signal. However, selective perfused, microbead-adherent requires highly effective suppression extracellular We describe how high-velocity perfusion results short apparent longitudinal transverse...

Familial hypobetalipoproteinemia (FHBL) subjects may develop fatty liver. Liver fat was assessed in 21 FHBL with six different apolipoprotein B (apoB) truncations (apoB-4 to apoB-89) and 14 controls by magnetic resonance spectroscopy (MRS). percentages were 16.7 ± 11.5 3.3 2.9 (mean SD) (P = 0.001). percentage positively correlated body mass index, waist circumference, areas under the insulin curves of 2 h glucose tolerance tests, suggesting that obesity affect severity liver accumulation...

Abstract Evaluation of water diffusion in the brain has revealed both fast‐ and slow‐diffusing populations. It been suggested that these populations represent extra‐ intracellular water, respectively. We have identified characterized space Xenopus oocyte. also determined their T 1 2 relaxation properties. The fast slow coefficients 1.06 ± 0.05 μm /ms 0.16 0.02 /ms, respectively, with fraction representing 89% 1% total signal. These values are quite similar to those for observed absence...

Severe bloodstream-borne infection--i.e., sepsis--and the resulting multiorgan failure are now most common cause of death in many intensive care units. One fundamentally important and controversial issues concerning pathophysiology sepsis is role intracellular free calcium concentration ([Ca2+]i) this disorder. Because critical as an second messenger a potential cellular toxin, resolution issue crucial. Using 19F NMR spectroscopy indicator...

High-resolution 31P nuclear magnetic resonance spectra at 73.83 MHz are reported for rat heart in vivo. In live rats, it was possible to observe the cardiac content of ATP, phosphocreatine, and Pi. Only a small amount whole-blood 2,3-diphosphoglycerate observed spectra, precluding possibility that blood phosphate compounds were masking compounds. The vivo perfused hearts similar support utilization as model system studying high-energy metabolism dynamic flux investigated by subjecting...

The use of deuterium oxide (2H2O) is proposed as a freely diffusible nuclear magnetic resonance (NMR) blood flow and tissue perfusion tracer potential clinical utility. Deuterium stable, nonradiative isotope commercially available 2H2O at enrichment levels essentially 100%--i.e., 110 molar equivalent deuterium. This high concentration, together with the short relaxation time spin 1 (quadrupole) nuclide, provides substantial sensitivity for NMR spectroscopy. As result, when administered in...

Abstract The contrast provided by diffusion‐sensitive magnetic resonance offers the promise of improved tumor localization in organ‐confined human prostate cancer (PCa). Diffusion tensor imaging (DTI) measurements PCa were performed vivo, patients undergoing radical prostatectomy, and later, ex same patients' prostatectomy specimens. data coregistered to histological sections specimens, thereby enabling unambiguous characterization diffusion parameters cancerous benign tissues. Increased...

Abstract BACKGROUND: Horseweed has been the most invasive glyphosate‐resistant (GR) weed, spreading to 16 states in United States and found on five continents. The authors have previously reported that GR horseweed employs rapid vacuolar sequestration of glyphosate, presumably via a tonoplast transporter, substantively reduce cytosolic glyphosate concentrations. 1 It was hypothesized herbicide resistance mechanism. If is indeed endowed by sequestration, suppression offers potential for...

Objective: The infant temperament behavioral inhibition is a potent risk factor for development of an anxiety disorder. It difficult to predict at birth, however, and the neural underpinnings are poorly understood. authors hypothesized that neonatal functional connectivity ventral attention network related age 2 years beyond sociodemographic familial factors. This hypothesis supported by network's role in novelty, key feature inhibition. Method: Using longitudinal design (N=45), measured...

Abstract Purpose: To quantify the effectiveness of anti-VEGF antibodies (bevacizumab and B20-4.1.1) as mitigators radiation-induced, central nervous system (brain) necrosis in a mouse model. Experimental Design: Cohorts mice were irradiated with single-fraction 50- or 60-Gy doses radiation targeted to left hemisphere using Leksell Perfexion Gamma Knife. The onset progression monitored longitudinally by vivo, small-animal MRI, beginning 4 weeks after irradiation. MRI-derived necrotic volumes...