Abstract:
:The MMQ cell line is a unique prolactin-secreting rat pituitary cell line. MMQ cells entrapped in agarose gel threads are metabolically active, as determined by the uptake and phosphorylation of creatine and the maintenance of high energy phosphates for over 15 h. Forskolin activates the catalytic subunit of adenylyl cyclase and, in MMQ cells, elevates the level of cAMP and stimulates prolactin secretion. 31P NMR spectroscopy was used to investigate the energy metabolism of the MMQ cells during stimulation by forskolin. The ability to measure small changes in the energy status of these cells was enhanced by increasing the PCr levels in the cells. Administration of forskolin to the perifused MMQ cells resulted in acute, reversible, and dose-dependent changes in the 31P NMR spectra of the cells within 12 to 24 min of the beginning of forskolin exposure. Several lines of evidence indicate that the changes observed in the MMQ cells are the composite result of the interaction of forskolin with adenylyl cyclase and the plasma membrane glucose transporter. Also, preincubation of the MMQ cells with the dopamine agonist, bromocriptine, attenuates the forskolin-stimulated decrease in the PCr resonance by approximately 50%. This attenuation indicates that the forskolin-stimulated changes in energy metabolism are probably related to the prolactin secretion process.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Goger MJ,Login IS,Fernandez EJ,Grisham CMdoi
10.1002/mrm.1910320507subject
Has Abstractpub_date
1994-11-01 00:00:00pages
584-91issue
5eissn
0740-3194issn
1522-2594journal_volume
32pub_type
杂志文章abstract:PURPOSE:To test and implement a motion-robust and respiratory-resolved 3D Radial Flow framework that addresses the need for rapid, high resolution imaging in neonatal patients with congenital heart disease. METHODS:A 4-point velocity encoding and 3D radial trajectory with double-golden angle ordering was combined with...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27945
更新日期:2020-02-01 00:00:00
abstract::In the recently proposed technique Sweep Imaging with Fourier Transform (SWIFT), frequency-modulated radiofrequency pulses are used in concert with simultaneous acquisition to facilitate MRI of samples with very short transverse relaxation time. In the present work, sweep MRI is reviewed from a reconstruction perspect...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22516
更新日期:2010-12-01 00:00:00
abstract::The myelin sheath, which is wrapped around the axons in the brain, can be affected by many diseases, resulting in cognitive and physical disability. Other work showed water in the myelin sheath has a T2 approximately 15 ms. The current standard technique to estimate the fraction of myelin water in vivo is to collect m...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.10713
更新日期:2004-03-01 00:00:00
abstract::The use of the minimum stored energy current density map-based methodology of designing closed-bore symmetric superconducting magnets was described recently. The technique is further developed to cater for the design of interventional-type MRI systems, and in particular open symmetric magnets of the double-doughnut co...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22189
更新日期:2010-01-01 00:00:00
abstract:PURPOSE:A ghost correction strategy for Simultaneous Multi-Slice (SMS) EPI methods that provides improved ghosting artifact reduction compared to conventional methods is presented. Conventional Nyquist ghost correction methods for SMS-EPI rely on navigator data that contain phase errors from all slices in the simultane...
journal_title:Magnetic resonance in medicine
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更新日期:2018-10-01 00:00:00
abstract::The assumption of linear time-invariance (LTI) in the human primary somatosensory cortex (SI) is assessed for fMRI signals generated by variable-duration vibrotactile stimuli. Predictions based on time-shifted summation (TSS) of responses to 2 s stimuli overestimate observed BOLD signal amplitudes in response to longe...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
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更新日期:2005-02-01 00:00:00
abstract::A method of post-processing to enhance the image resolution of the distribution of free radical molecules obtained with continuous-wave electron paramagnetic resonance (CW-EPR) imaging is reported. The low spatial resolution of EPR imaging, which has created difficulties in biomedical applications, was overcome by the...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22029
更新日期:2009-09-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910220254
更新日期:1991-12-01 00:00:00
abstract::A method for the acquisition of localized 2D shift-correlated spectra, based on the combination of the stimulated-echo volume-selection and gradient-enhanced COSY experiments, is described. The sequence can be modified to perform a number of localized experiments including HOHAHA and DQF-COSY. The method is demonstrat...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910320216
更新日期:1994-08-01 00:00:00
abstract:PURPOSE:To develop a method for retrospective artifact elimination of MRS data. This retrospective method was based on an approach that combines jackknife analyses with the correlation of spectral windows, and therefore termed "JKC." METHODS:Twelve healthy volunteers performed 3 separate measurement protocols using a ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27590
更新日期:2019-04-01 00:00:00
abstract::A stimulated echo sequence was used to obtain 19F NMR spectra from within a 4-ml voxel in a cat brain. The time dependence of the 19F NMR signal from an inert gas (CHF3) was used to calculate the blood flow in the voxel. The position of the voxel was selected using a 1H MR image. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910160316
更新日期:1990-12-01 00:00:00
abstract::The somatotopical organization of the human somatosensory cortex was analyzed with echo-planar imaging at 1.5 Tesla, utilizing deoxyhemoglobin as an endogenous contrast medium. Scrubbing stimulation at a frequency of 3 Hz was applied to one of three cutaneous areas: toes, fingertips, and tongue tip. Parasagittal echo-...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330521
更新日期:1995-05-01 00:00:00
abstract:PURPOSE:The diseased myocardium lacks metabolic flexibility and responds to stimuli differently compared with healthy hearts. Here, we report the use of hyperpolarized 13C NMR spectroscopy to detect sudden changes in cardiac metabolism in isolated, perfused rat hearts in response to adrenergic stimulation. METHODS:Met...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25419
更新日期:2015-08-01 00:00:00
abstract:PURPOSE:To improve quantification of myocardial blood flow using a fast T1 mapping technique using highly constrained back projection reconstruction (HYPR)-accelerated acquisition. METHODS:A major source of error in the measurement of myocardial blood flow (MBF) using MRI is the nonlinear relationship between image si...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24958
更新日期:2014-09-01 00:00:00
abstract::The ability to directly detect neuronal magnetic fields by MRI would help investigators achieve the "holy grail" of neuroimaging, namely both high spatial and temporal resolution. Both positive and negative findings have been reported in the literature, with no clear consensus as to the feasibility of direct detection...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21129
更新日期:2007-02-01 00:00:00
abstract:PURPOSE:Cross-term spatiotemporal encoding (xSPEN) is a single-shot approach with exceptional immunity to field heterogeneities, the images of which faithfully deliver 2D spatial distributions without requiring a priori information or using postacquisition corrections. xSPEN, however, suffers from signal-to-noise ratio...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26824
更新日期:2018-03-01 00:00:00
abstract::We have developed a method for measuring the electrocardiogram (ECG) continuously during MR examinations. In contrast to ECG acquisition by wires, our new method is to amplify and convert the ECG into an optical signal directly above the patient's heart. The optical signal is transmitted out of the magnet bore by opti...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910320416
更新日期:1994-10-01 00:00:00
abstract::Double wave vector diffusion weighting uses gradients along two different directions between excitation and acquisition. It has been shown theoretically that for restricted diffusion the signal amplitude in such an experiment can depend on the angle between the two gradient vectors. The highest amplitude is obtained w...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.21514
更新日期:2008-07-01 00:00:00
abstract::Stimulated-echo localized spectroscopy was combined with phase- and frequency-encoding gradients to obtain "zoom" or magnified images of specific organs in situ. The technique requires neither surface coils nor an imaging coil arrangement that exclusively isolates the target organ. This technique can be readily applie...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910050412
更新日期:1987-10-01 00:00:00
abstract::The recently developed technique of gradient, high-resolution magic-angle spinning NMR (g-hr-MAS-NMR) spectroscopy was applied to the study of ex vivo human lipoma and liposarcoma tissue. Compared with conventional 1H-NMR, the g-hr-MAS method yielded a large improvement in spectral resolution and permitted the detecti...
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doi:10.1002/mrm.1910380307
更新日期:1997-09-01 00:00:00
abstract::Transmit and receive RF coil arrays have proven to be particularly beneficial for ultra-high-field MR. Transmit coil arrays enable such techniques as B(1) (+) shimming to substantially improve transmit B(1) homogeneity compared to conventional volume coil designs, and receive coil arrays offer enhanced parallel imagin...
journal_title:Magnetic resonance in medicine
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更新日期:2010-06-01 00:00:00
abstract::Proton-electron double-resonance imaging (PEDRI) was used to assess renal function by monitoring the flow of the exogenous nitroxide free radical proxyl carboxylic acid (PCA) through normal and injured kidneys in the living rat. Kidney damage was induced by treatment with 2-bromoethylamine (BEA), which provides a well...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910400214
更新日期:1998-08-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.10622
更新日期:2003-12-01 00:00:00
abstract::We used deuterium magnetic resonance imaging (2H MRI) to visualize water movement in the rabbit eye. Dynamic 2H MRI was obtained every 3.5 min at 2 tesla by FLASH pulse sequence (TR, 300 ms; TE, 10 ms; alpha = 90 degrees) with a slice thickness of 10 mm using a surface coil (4 cm in diameter). After topical administra...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910330417
更新日期:1995-04-01 00:00:00
abstract:PURPOSE:Waveguide elastography (WGE) combines magnetic resonance elastography (MRE), diffusion tensor imaging (DTI), and anisotropic inversions for a determination of the elastic properties of white matter. Previously, the method evaluated the anisotropic elastic properties of the corticospinal tracts (CSTs) of healthy...
journal_title:Magnetic resonance in medicine
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更新日期:2014-12-01 00:00:00
abstract::Comparative NMR studies of normal and pathologically altered human stomach tissues were performed on the basis of proton T1 relaxation time measurements in the presence of high external concentrations of relaxation (contrast) agents manganese ethylenediaminetetraacetic acid (Mn-EDTA) and gadolinium diethylenetriaminep...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
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更新日期:1990-09-01 00:00:00
abstract::In order to determine if an increase in myocardial oxygen consumption is accompanied by changes in high energy phosphates in normal subjects and patients with dilated cardiomyopathy, phosphorus-31 spectra were acquired under resting conditions and during dobutamine infusion. In seven normal subjects, dobutamine raised...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910250205
更新日期:1992-06-01 00:00:00
abstract:PURPOSE:T2 -weighted sequences are particularly sensitive to the radiofrequency (RF) field inhomogeneity problem at ultra-high-field because of the errors accumulated by the imperfections of the train of refocusing pulses. As parallel transmission (pTx) has proved particularly useful to counteract RF heterogeneities, u...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.27001
更新日期:2018-07-01 00:00:00
abstract::The advent of event-related functional magnetic resonance imaging (fMRI) has resulted in many exciting studies that have exploited its unique capability. However, the utility of event-related fMRI is still limited by several technical difficulties. One significant limitation in event-related fMRI is the low signal-to-...
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doi:10.1002/1522-2594(200011)44:5<746::aid-mrm13>3.0.c
更新日期:2000-11-01 00:00:00
abstract:PURPOSE:A systematic study of the short-term and long-term variability of regional alveolar partial pressure of oxygen tension (pA O2 ) measurements using (3) He magnetic resonance imaging was presented. Additionally, the repeatability of the average evaluated pA O2 was compared with that of the standard pulmonary func...
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更新日期:2013-12-01 00:00:00