Linda Jelicks - Profile on Academia.edu (original) (raw)
Papers by Linda Jelicks
Depletion of intracellular free magnesium in rat hearts during acute alcohol perfusion: a 31P nuclear magnetic resonance study
Magnesium and trace elements
ABSTRACT
NMR Measurement of Cytosolic Free Calcium, Free Magnesium, and Intracellular Sodium in the Aorta of the Normal and Spontaneously Hypertensive Rat
Journal of Biological Chemistry
We have utilized multinuclear NMR spectroscopy to examine the relationship between cytosolic free... more We have utilized multinuclear NMR spectroscopy to examine the relationship between cytosolic free Ca2+ ([Ca2+]in), free Mg2+ ([Mg2+]in) and intracellular Na+ ([Na+]in) levels of the intact thoracic aorta and primary hypertension using the Wistar-Kyoto and Sprague-Dawley rats as controls and the spontaneously hypertensive rat as a model for genetic hypertension. Cytosolic free [Ca2+] was measured using 19F NMR of the intracellular Ca2+ indicator 5,5'-difluoro-1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, free [Mg2+] using the 31P resonances of intracellular ATP, and intracellular [Na+] by 23Na NMR in combination with the extracellular shift reagent dysprosium tripolyphosphate. We have found that both the [Na+]in and [Ca2+]in levels were significantly increased in the hypertensive animals relative to normotensive controls (p less than 0.01). Mean systolic blood pressures (using tail cuff method) of control and hypertensive rats were 123 +/- 8 mm Hg (mean +/- 2 S.E., n = 7) and 159 +/- 6 mm Hg (mean +/- 2 S.E., n = 7), respectively. [Na+]in and [Ca2+]in were 21.9 +/- 6.4 mM (mean +/- 2 S.E., n = 7) and 277 +/- 28 nM (mean +/- 2 S.E., n = 5) for the spontaneously hypertensive rats versus 10.1 +/- 1.8 mM (mean +/- 2 S.E., n = 7) and 151 +/- 26 nM (mean +/- 2 S.E., n = 5) for control rats, respectively. A slight difference observed between intracellular free Mg2+ levels in hypertensives (180 +/- 38 microM, mean +/- 2 S.E., n = 4) and controls (246 +/- 76 microM, mean +/- 2 S.E., n = 4) was not statistically significant (p greater than 0.1). These data indicate alterations in the cell membrane ion transport function of the aortic smooth muscle in primary hypertension.
Diabetes, 2014
Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyper... more Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyperglycemia, and insulin resistance. In addition, carbohydrate utilization as a fuel is substantially inhibited. Correction or reversal of these effects during high-fat diet (HFD) intake is of exceptional interest in light of widespread occurrence of diet-associated metabolic disorders in global human populations. Here we report that mangiferin (MGF), a natural compound (the predominant constituent of Mangifera indica extract from the plant that produces mango), protected against HFD-induced weight gain, increased aerobic mitochondrial capacity and thermogenesis, and improved glucose and insulin profiles. To obtain mechanistic insight into the basis for these effects, we determined that mice exposed to an HFD combined with MGF exhibited a substantial shift in respiratory quotient from fatty acid toward carbohydrate utilization. MGF treatment significantly increased glucose oxidation in musc...
Nuclear magnetic resonance measurement of intracellular sodium in the perfused normotensive and spontaneously hypertensive rat heart
American Journal of Hypertension
We have used 23Na nuclear magnetic resonance spectroscopy to examine the relationship between int... more We have used 23Na nuclear magnetic resonance spectroscopy to examine the relationship between intracellular sodium and cardiac muscle alterations in genetic hypertension. In the spontaneously hypertensive rat (SHR) compared with the normotensive Wistar-Kyoto rat (WKY) (aged 15 to 19 weeks), mean systolic blood pressures (measured using the tail-cuff method) were significantly (P < .05) different (WKY: 118 +/- 8 mm Hg, n = 5; SHR: 185 +/- 9 mm Hg, n = 5). Heart weights were also increased significantly (P < .05) in SHR (grams dry heart to kilograms body weight ratio was 0.73 +/- 0.04, n = 5, for SHR and 0.55 +/- 0.02, n = 5, for WKY). Intracellular sodium levels, measured using shift-reagent-aided and triple quantum filtered (TQF) nuclear magnetic resonance techniques, were significantly increased (P < .05) in the isolated Langendorff perfused hypertensive rat hearts (17.3 +/- 3.6 mmol/L, n = 5) compared with normotensive rat hearts (8.4 +/- 2.3 mmol/L, n = 5). These data demonstrate increased sodium in cardiac muscle in essential hypertension. We also investigated the effect of pacing on cardiac TQF 23Na nuclear magnetic resonance and found an increase in TQF Na+ content in both WKY and SHR hearts on stepped up pacing. These results support the existence of sodium pump lag in the rat heart perfused at physiologic Ca2+ concentration and suggest that the hypertensive rat heart has adapted to compensate for increased basal intracellular Na+ and maintain a normal response to increased heart rate. Our data appear to suggest an ionic contribution to the cardiac hypertrophy of genetic hypertension in the rat.
31P-NMR of high-energy phosphates in perfused rat heart during metabolic acidosis
The American journal of physiology
Intracellular pH (pHi), intracellular free magnesium concentration ([Mg2+]i), and high-energy pho... more Intracellular pH (pHi), intracellular free magnesium concentration ([Mg2+]i), and high-energy phosphates in Langendorff perfused rat hearts were evaluated by 31P-nuclear magnetic resonance (NMR) during metabolic acidosis. During acidosis, cardiac pHi approached that of the perfusing solution (pH approximately 6.7) and [Mg2+]i increased. In hearts perfused with glucose as the sole carbon source, the ratio of [phosphocreatine] to [ATP] decreased during acidosis. In contrast, in hearts supplemented with pyruvate (either 2.8 or 10 mM) this ratio increased during acidosis. Oxygen consumption decreased in hearts perfused with glucose only and with pyruvate-glucose. Using the creatine kinase equilibrium constant, we find that [MgADP] is significantly decreased in pyruvate-perfused hearts but is not significantly altered in glucose-perfused hearts during metabolic acidosis. These data indicate that [MgADP] may be the regulator of cardiac oxidative phosphorylation in the presence of excess pyruvate; however, during metabolic acidosis in hearts perfused with glucose only, ATP synthesis appears limited by the availability of pyruvate via glycolysis.
Observation of intracellular sodium ions by double-quantum-filtered 23Na NMR with paramagnetic quenching of extracellular coherence by gadolinium tripolyphosphate
Journal of Magnetic Resonance (1969), 1989
Journal of Magnetic Resonance (1969), 1989
It has been suggested that a double-quantum filter may allow the noninvasive discrimination of di... more It has been suggested that a double-quantum filter may allow the noninvasive discrimination of different pools of Na+ in vivo (l-3). For quadrupolar nuclei (I > :) double-quantum coherence can be excited by biexponential relaxation (4). Biexponential relaxation is observed for 23Na+ when the extreme narrowing condition does not hold. Under such conditions the outer transitions (-i -P -f and 4 + f) decay more quickly than the inner transition ( -4 + $) (3). Biexponential relaxation induces violations of the coherence transfer selection rules that can be described by representing the evolution of coherence in terms of irreducible spherical tensor operators (5). Double-quantum coherence can be detected using the phase-cycled "INAD-EQUATE" double-quantum filter of Bax (6) :
Roles of Mg2+ and Ca2+ in beneficial vs. detrimental actions of alcohol on heart
Biomedical Vibrational Spectroscopy and Biohazard Detection Technologies, 2004
Raman and FTIR microprobe spectroscopy have been used to characterize the atherosclerotic process... more Raman and FTIR microprobe spectroscopy have been used to characterize the atherosclerotic process in Apo E and wild type mice. The Apo E null mouse is being studied in parallel with a healthy strain as a model of the human atherosclerotic disease. Preliminary Raman microprobe spectra have been recorded from the lumen of the aorta vessels from a normal black
![Research paper thumbnail of Effects of hypertrophy and heart failure on [Na+]i in pressure-overloaded guinea pig heart](https://attachments.academia-assets.com/55158925/thumbnails/1.jpg)
](American journal of hypertension, 1995
Intracellular free sodium levels ([Na+]i) were assessed with 23Na nuclear magnetic resonance (NMR... more Intracellular free sodium levels ([Na+]i) were assessed with 23Na nuclear magnetic resonance (NMR) spectroscopy in isolated, Langendorff-perfused normal, compensated hypertrophied, and hypertrophied failing guinea pig hearts under several conditions. Baseline [Na+]i measured with a shift reagent was significantly greater than normal in the compensated hypertrophied hearts (12.8 +/- 1.2 mmol/L v 6.4 +/- 0.7 mmol/L, means +/- SEM, P < .01), but not in the hypertrophied failing hearts (8.7 +/- 1.9 mmol/L, P = N.S.). Moreover, the highest levels of [Na+]i were seen just 3 to 4 weeks after aortic constriction. [Na+]i was inversely related to both time after aortic constriction (R = -0.71, P < .03) and to the degree of left ventricular hypertrophy (R = -0.79, P < .01), suggesting that the hypertrophied failing heart is capable of maintaining relatively normal [Na+]i. In addition, triple quantum filtered NMR measurements were made to assess changes in [Na+]i subsequent to altered ...
Intracellular free magnesium and high energy phosphates in the perfused normotensive and spontaneously hypertensive rat heart. A 31P NMR study
American journal of hypertension, 1991
We have employed 31P nuclear magnetic resonance (NMR) spectroscopy to examine the relationship be... more We have employed 31P nuclear magnetic resonance (NMR) spectroscopy to examine the relationship between cytosolic free Mg2+ ([Mg2+]in), intracellular pH, high energy phosphates, and genetic hypertension using the Wistar-Kyoto rat (WKY) as a control and the spontaneously hypertensive rat (SHR) as a model for essential hypertension. The mean systolic blood pressures (measured using the tail cuff method) of control and hypertensive rats (aged 7 to 12 weeks) were 113 +/- 4 mm Hg (mean +/- 2 SE, n = 14) and 162 +/- 5 mm Hg (mean +/- 2 SE, n = 17), respectively. Intracellular free Mg2+ levels were significantly depleted in the isolated Langendorff perfused hypertensive rat hearts (452 +/- 39 mumol/L, mean +/- 2 SE, n = 17) compared to control hearts (756 +/- 52 mumol/L, n = 14); however, intracellular pH did not differ in the SHR hearts (7.02 +/- 0.03, mean +/- 2 SE, n = 7) compared with controls (7.03 +/- 0.03, n = 7). Although we could not demonstrate a statistically significant differen...
Synthesis and Conformational Studies of O 5′ , 6-Methanouridine—A New Type of Pyrimidine Cyclonucleoside
Nucleosides and Nucleotides, 1992
RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...
Detection of Cartilage Degradation with Sodium NMR
Rheumatology, 1991
Use of Vibrational Spectroscopy to Elucidate the Atherosclerotic Disease Process in the Apo E Knock-out Mouse Model
Microscopy and Microanalysis, 2004
Biophysical Journal, 1995
The proximal histidine NH proton of deoxymyoglobin experiences a large hyperfine shift resulting ... more The proximal histidine NH proton of deoxymyoglobin experiences a large hyperfine shift resulting in its 'H nuclear magnetic resonance (NMR) signal appearing at -76 ppm (at 350C), downfield of the diamagnetic spectral region. 'H NMR of this proton is used to monitor sarcoplasmic oxygen pressure in isolated perfused rat heart. This method monitors intracellular oxygenation in the whole heart and does not reflect oxygenation in a limited region. The deoxymyoglobin resonance intensity is reduced upon conversion of myoglobin to the ferric form by sodium nitrite. 'H resonances of the N8H protons of the a and subunits of bovine deoxyhemoglobin do not interfere with the measurement of myoglobin deoxygenation in blood-perfused rat heart. We find that steady-state myoglobin deoxygenation is increased progressively (and reversibly) as oxygenation of the perfusing medium is decreased in both saline and red blood cell-perfused hearts at constant work output. An eightfold increase in the heart rate of the blood-perfused heart resulted in no change in the deoxymyoglobin signal intensity. Intracellular P02 of myoglobin-containing cells is maintained remarkably constant in changing work states.
Gated magnetic resonance imaging of normal and hypertrophied murine hearts
American Journal of …, 1997
Transgenic murine models are being used increasingly to explore the molecular basis of heart dise... more Transgenic murine models are being used increasingly to explore the molecular basis of heart disease. Until recently, there were no means for noninvasive assessment of changes in mass and function of the murine heart because of its very small size and high heart rate. Transthoracic echocardiography has now been utilized to obtain noninvasive estimates of murine left ventricular (LV) wall thicknesses, internal dimension, and mass. However, this approach is based on one-dimensional (M-mode) measurements of the LV at its midwall that take no account of variations in LV chamber and wall dimensions along other minor axes and at other anatomic levels. Thus asymmetries in LV geometry, which can affect LV mass estimates, may be undetected. In this study, gated (diastolic) magnetic resonance imaging (MRI) was utilized to obtain two-dimensional images of the LV at four anatomic levels in intact, anesthetized mice. In 17 normal CD-1 mice (body mass, 18-47 g; gravimetric LV mass, 51-135 mg), LV mass estimates produced from the MRI data correlated well (r = 0.87) with LV mass determined gravimetrically. In addition, this approach identified changes in LV mass and wall thickness-to-chamber diameter ratio in a group of seven aortic-constricted mice (body mass, 32-39 g; gravimetric LV mass, 119-198 mg) with compensated and decompensated LV hypertrophy. These findings suggest that utility of MRI for serial, noninvasive assessment of experimentally induced alterations in mass and geometry of the murine heart.
Correction: Optimized labeling of bone marrow mesenchymal cells with superparamagnetic iron oxide nanoparticles and in vivo visualization by magnetic resonance imaging
Journal of Nanobiotechnology, 2011
Background Stem cell therapy has emerged as a promising addition to traditional treatments for a... more Background Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label and visualize
Journal of Nanobiotechnology, 2011
Background: Stem cell therapy has emerged as a promising addition to traditional treatments for a... more Background: Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label and visualize various cell types with magnetic resonance imaging (MRI). In this study we performed experiments designed to investigate the biological properties, including proliferation, viability and differentiation capacity of mesenchymal cells (MSCs) labeled with clinically approved SPIONs.
Hepatology
Human obesity is associated with abnormal hepatic cholesterol homeostasis and resistance to lepti... more Human obesity is associated with abnormal hepatic cholesterol homeostasis and resistance to leptin action. Because leptin administration to rodents promotes the biliary elimination of plasma cholesterol, this study was designed to elucidate a pathophysiological role for leptin during the development of obesity. We fed mice diets containing high or low saturated fat contents. Before and after the onset of obesity, we measured downstream targets of leptin action and evaluated plasma, hepatic, and biliary cholesterol metabolism. Although not obese at 28 days, mice fed a high fat diet became hyperleptinemic. Sensitivity to leptin was evidenced by downregulation of both hepatic stearoyl CoA desaturase-1 and fatty acid synthase. Due principally to upregulation of adenosine triphosphate-binding cassette proteins A1 and G5, plasma high density lipoprotein (HDL) cholesterol concentrations increased, as did relative secretion rates of biliary cholesterol. A smaller, more hydrophilic bile salt pool decreased intestinal cholesterol absorption. In this setting, hepatic cholesterol synthesis was downregulated, indicative of increased uptake of plasma cholesterol. After 56 days of high fat feeding, obesity was associated with leptin resistance, as evidenced by marked hyperleptinemia without downregulation of stearoyl CoA desaturase-1 or fatty acid synthase and by upregulation of hepatic cholesterol and bile salt synthesis. Hypercholesterolemia was attributable to overproduction and decreased clearance of large HDL 1 particles. In conclusion, before the onset of obesity, preserved leptin sensitivity promotes biliary elimination of endogenous cholesterol in response to dietary fat. Leptin resistance due to obesity leads to a maladaptive response whereby newly synthesized cholesterol in the liver is eliminated via bile. (HEPATOLOGY 2005;41:887-895.)
Depletion of intracellular free magnesium in rat hearts during acute alcohol perfusion: a 31P nuclear magnetic resonance study
Magnesium and trace elements
ABSTRACT
NMR Measurement of Cytosolic Free Calcium, Free Magnesium, and Intracellular Sodium in the Aorta of the Normal and Spontaneously Hypertensive Rat
Journal of Biological Chemistry
We have utilized multinuclear NMR spectroscopy to examine the relationship between cytosolic free... more We have utilized multinuclear NMR spectroscopy to examine the relationship between cytosolic free Ca2+ ([Ca2+]in), free Mg2+ ([Mg2+]in) and intracellular Na+ ([Na+]in) levels of the intact thoracic aorta and primary hypertension using the Wistar-Kyoto and Sprague-Dawley rats as controls and the spontaneously hypertensive rat as a model for genetic hypertension. Cytosolic free [Ca2+] was measured using 19F NMR of the intracellular Ca2+ indicator 5,5'-difluoro-1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, free [Mg2+] using the 31P resonances of intracellular ATP, and intracellular [Na+] by 23Na NMR in combination with the extracellular shift reagent dysprosium tripolyphosphate. We have found that both the [Na+]in and [Ca2+]in levels were significantly increased in the hypertensive animals relative to normotensive controls (p less than 0.01). Mean systolic blood pressures (using tail cuff method) of control and hypertensive rats were 123 +/- 8 mm Hg (mean +/- 2 S.E., n = 7) and 159 +/- 6 mm Hg (mean +/- 2 S.E., n = 7), respectively. [Na+]in and [Ca2+]in were 21.9 +/- 6.4 mM (mean +/- 2 S.E., n = 7) and 277 +/- 28 nM (mean +/- 2 S.E., n = 5) for the spontaneously hypertensive rats versus 10.1 +/- 1.8 mM (mean +/- 2 S.E., n = 7) and 151 +/- 26 nM (mean +/- 2 S.E., n = 5) for control rats, respectively. A slight difference observed between intracellular free Mg2+ levels in hypertensives (180 +/- 38 microM, mean +/- 2 S.E., n = 4) and controls (246 +/- 76 microM, mean +/- 2 S.E., n = 4) was not statistically significant (p greater than 0.1). These data indicate alterations in the cell membrane ion transport function of the aortic smooth muscle in primary hypertension.
Diabetes, 2014
Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyper... more Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyperglycemia, and insulin resistance. In addition, carbohydrate utilization as a fuel is substantially inhibited. Correction or reversal of these effects during high-fat diet (HFD) intake is of exceptional interest in light of widespread occurrence of diet-associated metabolic disorders in global human populations. Here we report that mangiferin (MGF), a natural compound (the predominant constituent of Mangifera indica extract from the plant that produces mango), protected against HFD-induced weight gain, increased aerobic mitochondrial capacity and thermogenesis, and improved glucose and insulin profiles. To obtain mechanistic insight into the basis for these effects, we determined that mice exposed to an HFD combined with MGF exhibited a substantial shift in respiratory quotient from fatty acid toward carbohydrate utilization. MGF treatment significantly increased glucose oxidation in musc...
Nuclear magnetic resonance measurement of intracellular sodium in the perfused normotensive and spontaneously hypertensive rat heart
American Journal of Hypertension
We have used 23Na nuclear magnetic resonance spectroscopy to examine the relationship between int... more We have used 23Na nuclear magnetic resonance spectroscopy to examine the relationship between intracellular sodium and cardiac muscle alterations in genetic hypertension. In the spontaneously hypertensive rat (SHR) compared with the normotensive Wistar-Kyoto rat (WKY) (aged 15 to 19 weeks), mean systolic blood pressures (measured using the tail-cuff method) were significantly (P < .05) different (WKY: 118 +/- 8 mm Hg, n = 5; SHR: 185 +/- 9 mm Hg, n = 5). Heart weights were also increased significantly (P < .05) in SHR (grams dry heart to kilograms body weight ratio was 0.73 +/- 0.04, n = 5, for SHR and 0.55 +/- 0.02, n = 5, for WKY). Intracellular sodium levels, measured using shift-reagent-aided and triple quantum filtered (TQF) nuclear magnetic resonance techniques, were significantly increased (P < .05) in the isolated Langendorff perfused hypertensive rat hearts (17.3 +/- 3.6 mmol/L, n = 5) compared with normotensive rat hearts (8.4 +/- 2.3 mmol/L, n = 5). These data demonstrate increased sodium in cardiac muscle in essential hypertension. We also investigated the effect of pacing on cardiac TQF 23Na nuclear magnetic resonance and found an increase in TQF Na+ content in both WKY and SHR hearts on stepped up pacing. These results support the existence of sodium pump lag in the rat heart perfused at physiologic Ca2+ concentration and suggest that the hypertensive rat heart has adapted to compensate for increased basal intracellular Na+ and maintain a normal response to increased heart rate. Our data appear to suggest an ionic contribution to the cardiac hypertrophy of genetic hypertension in the rat.
31P-NMR of high-energy phosphates in perfused rat heart during metabolic acidosis
The American journal of physiology
Intracellular pH (pHi), intracellular free magnesium concentration ([Mg2+]i), and high-energy pho... more Intracellular pH (pHi), intracellular free magnesium concentration ([Mg2+]i), and high-energy phosphates in Langendorff perfused rat hearts were evaluated by 31P-nuclear magnetic resonance (NMR) during metabolic acidosis. During acidosis, cardiac pHi approached that of the perfusing solution (pH approximately 6.7) and [Mg2+]i increased. In hearts perfused with glucose as the sole carbon source, the ratio of [phosphocreatine] to [ATP] decreased during acidosis. In contrast, in hearts supplemented with pyruvate (either 2.8 or 10 mM) this ratio increased during acidosis. Oxygen consumption decreased in hearts perfused with glucose only and with pyruvate-glucose. Using the creatine kinase equilibrium constant, we find that [MgADP] is significantly decreased in pyruvate-perfused hearts but is not significantly altered in glucose-perfused hearts during metabolic acidosis. These data indicate that [MgADP] may be the regulator of cardiac oxidative phosphorylation in the presence of excess pyruvate; however, during metabolic acidosis in hearts perfused with glucose only, ATP synthesis appears limited by the availability of pyruvate via glycolysis.
Observation of intracellular sodium ions by double-quantum-filtered 23Na NMR with paramagnetic quenching of extracellular coherence by gadolinium tripolyphosphate
Journal of Magnetic Resonance (1969), 1989
Journal of Magnetic Resonance (1969), 1989
It has been suggested that a double-quantum filter may allow the noninvasive discrimination of di... more It has been suggested that a double-quantum filter may allow the noninvasive discrimination of different pools of Na+ in vivo (l-3). For quadrupolar nuclei (I > :) double-quantum coherence can be excited by biexponential relaxation (4). Biexponential relaxation is observed for 23Na+ when the extreme narrowing condition does not hold. Under such conditions the outer transitions (-i -P -f and 4 + f) decay more quickly than the inner transition ( -4 + $) (3). Biexponential relaxation induces violations of the coherence transfer selection rules that can be described by representing the evolution of coherence in terms of irreducible spherical tensor operators (5). Double-quantum coherence can be detected using the phase-cycled "INAD-EQUATE" double-quantum filter of Bax (6) :
Roles of Mg2+ and Ca2+ in beneficial vs. detrimental actions of alcohol on heart
Biomedical Vibrational Spectroscopy and Biohazard Detection Technologies, 2004
Raman and FTIR microprobe spectroscopy have been used to characterize the atherosclerotic process... more Raman and FTIR microprobe spectroscopy have been used to characterize the atherosclerotic process in Apo E and wild type mice. The Apo E null mouse is being studied in parallel with a healthy strain as a model of the human atherosclerotic disease. Preliminary Raman microprobe spectra have been recorded from the lumen of the aorta vessels from a normal black
American journal of hypertension, 1995
Intracellular free sodium levels ([Na+]i) were assessed with 23Na nuclear magnetic resonance (NMR... more Intracellular free sodium levels ([Na+]i) were assessed with 23Na nuclear magnetic resonance (NMR) spectroscopy in isolated, Langendorff-perfused normal, compensated hypertrophied, and hypertrophied failing guinea pig hearts under several conditions. Baseline [Na+]i measured with a shift reagent was significantly greater than normal in the compensated hypertrophied hearts (12.8 +/- 1.2 mmol/L v 6.4 +/- 0.7 mmol/L, means +/- SEM, P < .01), but not in the hypertrophied failing hearts (8.7 +/- 1.9 mmol/L, P = N.S.). Moreover, the highest levels of [Na+]i were seen just 3 to 4 weeks after aortic constriction. [Na+]i was inversely related to both time after aortic constriction (R = -0.71, P < .03) and to the degree of left ventricular hypertrophy (R = -0.79, P < .01), suggesting that the hypertrophied failing heart is capable of maintaining relatively normal [Na+]i. In addition, triple quantum filtered NMR measurements were made to assess changes in [Na+]i subsequent to altered ...
Intracellular free magnesium and high energy phosphates in the perfused normotensive and spontaneously hypertensive rat heart. A 31P NMR study
American journal of hypertension, 1991
We have employed 31P nuclear magnetic resonance (NMR) spectroscopy to examine the relationship be... more We have employed 31P nuclear magnetic resonance (NMR) spectroscopy to examine the relationship between cytosolic free Mg2+ ([Mg2+]in), intracellular pH, high energy phosphates, and genetic hypertension using the Wistar-Kyoto rat (WKY) as a control and the spontaneously hypertensive rat (SHR) as a model for essential hypertension. The mean systolic blood pressures (measured using the tail cuff method) of control and hypertensive rats (aged 7 to 12 weeks) were 113 +/- 4 mm Hg (mean +/- 2 SE, n = 14) and 162 +/- 5 mm Hg (mean +/- 2 SE, n = 17), respectively. Intracellular free Mg2+ levels were significantly depleted in the isolated Langendorff perfused hypertensive rat hearts (452 +/- 39 mumol/L, mean +/- 2 SE, n = 17) compared to control hearts (756 +/- 52 mumol/L, n = 14); however, intracellular pH did not differ in the SHR hearts (7.02 +/- 0.03, mean +/- 2 SE, n = 7) compared with controls (7.03 +/- 0.03, n = 7). Although we could not demonstrate a statistically significant differen...
Synthesis and Conformational Studies of O 5′ , 6-Methanouridine—A New Type of Pyrimidine Cyclonucleoside
Nucleosides and Nucleotides, 1992
RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...
Detection of Cartilage Degradation with Sodium NMR
Rheumatology, 1991
Use of Vibrational Spectroscopy to Elucidate the Atherosclerotic Disease Process in the Apo E Knock-out Mouse Model
Microscopy and Microanalysis, 2004
Biophysical Journal, 1995
The proximal histidine NH proton of deoxymyoglobin experiences a large hyperfine shift resulting ... more The proximal histidine NH proton of deoxymyoglobin experiences a large hyperfine shift resulting in its 'H nuclear magnetic resonance (NMR) signal appearing at -76 ppm (at 350C), downfield of the diamagnetic spectral region. 'H NMR of this proton is used to monitor sarcoplasmic oxygen pressure in isolated perfused rat heart. This method monitors intracellular oxygenation in the whole heart and does not reflect oxygenation in a limited region. The deoxymyoglobin resonance intensity is reduced upon conversion of myoglobin to the ferric form by sodium nitrite. 'H resonances of the N8H protons of the a and subunits of bovine deoxyhemoglobin do not interfere with the measurement of myoglobin deoxygenation in blood-perfused rat heart. We find that steady-state myoglobin deoxygenation is increased progressively (and reversibly) as oxygenation of the perfusing medium is decreased in both saline and red blood cell-perfused hearts at constant work output. An eightfold increase in the heart rate of the blood-perfused heart resulted in no change in the deoxymyoglobin signal intensity. Intracellular P02 of myoglobin-containing cells is maintained remarkably constant in changing work states.
Gated magnetic resonance imaging of normal and hypertrophied murine hearts
American Journal of …, 1997
Transgenic murine models are being used increasingly to explore the molecular basis of heart dise... more Transgenic murine models are being used increasingly to explore the molecular basis of heart disease. Until recently, there were no means for noninvasive assessment of changes in mass and function of the murine heart because of its very small size and high heart rate. Transthoracic echocardiography has now been utilized to obtain noninvasive estimates of murine left ventricular (LV) wall thicknesses, internal dimension, and mass. However, this approach is based on one-dimensional (M-mode) measurements of the LV at its midwall that take no account of variations in LV chamber and wall dimensions along other minor axes and at other anatomic levels. Thus asymmetries in LV geometry, which can affect LV mass estimates, may be undetected. In this study, gated (diastolic) magnetic resonance imaging (MRI) was utilized to obtain two-dimensional images of the LV at four anatomic levels in intact, anesthetized mice. In 17 normal CD-1 mice (body mass, 18-47 g; gravimetric LV mass, 51-135 mg), LV mass estimates produced from the MRI data correlated well (r = 0.87) with LV mass determined gravimetrically. In addition, this approach identified changes in LV mass and wall thickness-to-chamber diameter ratio in a group of seven aortic-constricted mice (body mass, 32-39 g; gravimetric LV mass, 119-198 mg) with compensated and decompensated LV hypertrophy. These findings suggest that utility of MRI for serial, noninvasive assessment of experimentally induced alterations in mass and geometry of the murine heart.
Correction: Optimized labeling of bone marrow mesenchymal cells with superparamagnetic iron oxide nanoparticles and in vivo visualization by magnetic resonance imaging
Journal of Nanobiotechnology, 2011
Background Stem cell therapy has emerged as a promising addition to traditional treatments for a... more Background Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label and visualize
Journal of Nanobiotechnology, 2011
Background: Stem cell therapy has emerged as a promising addition to traditional treatments for a... more Background: Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label and visualize various cell types with magnetic resonance imaging (MRI). In this study we performed experiments designed to investigate the biological properties, including proliferation, viability and differentiation capacity of mesenchymal cells (MSCs) labeled with clinically approved SPIONs.
Hepatology
Human obesity is associated with abnormal hepatic cholesterol homeostasis and resistance to lepti... more Human obesity is associated with abnormal hepatic cholesterol homeostasis and resistance to leptin action. Because leptin administration to rodents promotes the biliary elimination of plasma cholesterol, this study was designed to elucidate a pathophysiological role for leptin during the development of obesity. We fed mice diets containing high or low saturated fat contents. Before and after the onset of obesity, we measured downstream targets of leptin action and evaluated plasma, hepatic, and biliary cholesterol metabolism. Although not obese at 28 days, mice fed a high fat diet became hyperleptinemic. Sensitivity to leptin was evidenced by downregulation of both hepatic stearoyl CoA desaturase-1 and fatty acid synthase. Due principally to upregulation of adenosine triphosphate-binding cassette proteins A1 and G5, plasma high density lipoprotein (HDL) cholesterol concentrations increased, as did relative secretion rates of biliary cholesterol. A smaller, more hydrophilic bile salt pool decreased intestinal cholesterol absorption. In this setting, hepatic cholesterol synthesis was downregulated, indicative of increased uptake of plasma cholesterol. After 56 days of high fat feeding, obesity was associated with leptin resistance, as evidenced by marked hyperleptinemia without downregulation of stearoyl CoA desaturase-1 or fatty acid synthase and by upregulation of hepatic cholesterol and bile salt synthesis. Hypercholesterolemia was attributable to overproduction and decreased clearance of large HDL 1 particles. In conclusion, before the onset of obesity, preserved leptin sensitivity promotes biliary elimination of endogenous cholesterol in response to dietary fat. Leptin resistance due to obesity leads to a maladaptive response whereby newly synthesized cholesterol in the liver is eliminated via bile. (HEPATOLOGY 2005;41:887-895.)