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Papers by Brett Schonekess

Research paper thumbnail of Energy metabolism in the hypertrophied heart

Research paper thumbnail of Regulation of fatty acid oxidation in the mammalian heart in health and disease

Biochimica et biophysica acta, Aug 1, 1994

Research paper thumbnail of Recovery of glycolysis and oxidative metabolism during postischemic reperfusion of hypertrophied rat hearts

American Journal of Physiology-heart and Circulatory Physiology, Aug 1, 1996

We investigated the source and extent of recovery of ATP production during postischemic reperfusi... more We investigated the source and extent of recovery of ATP production during postischemic reperfusion of isolated working hearts from abdominal aortic-banded rats. Rates of glycolysis, glucose oxidation, lactate oxidation, and palmitate oxidation were measured in hypertrophied and control hearts [perfused with (in mM) 11 glucose, 0.5 lactate, and 1.2 palmitate] during and after 30 min of no-flow ischemia. In the initial aerobic period glycolytic rates were 1.87-fold higher in hypertrophied hearts compared with control hearts (P < 0.05), with rates of carbohydrate and palmitate oxidation being similar. During reperfusion, hypertrophied hearts recovered 40% of preischemic function compared with 71% in control hearts. Rates of glycolysis during reperfusion of hypertrophied hearts remained accelerated compared with control hearts (2.01-fold higher, P < 0.05), whereas oxidative metabolism returned to preischemic values in both groups. The efficiency of converting ATP production into mechanical work decreased to 29% of preischemic values in hypertrophied hearts during the postischemic reperfusion compared with a decrease to only 59% of preischemic values in control hearts. This suggests that the recovery of glycolysis and oxidative metabolism in the hypertrophied heart during postischemic reperfusion is not impaired, but rather the efficiency of converting ATP produced into mechanical function decreases.

Research paper thumbnail of Propionyl <scp>l</scp> -Carnitine Improvement of Hypertrophied Heart Function Is Accompanied by an Increase in Carbohydrate Oxidation

Circulation Research, Oct 1, 1995

Propionyl l -carnitine (PLC) is a naturally occurring derivative of l -carnitine that can improve... more Propionyl l -carnitine (PLC) is a naturally occurring derivative of l -carnitine that can improve hemodynamic function of hypertrophied rat hearts. The mechanism(s) responsible for the beneficial effects of PLC is not known, although improvement of myocardial energy metabolism has been suggested. In this study, we determined the effect of PLC on carbohydrate and fatty acid metabolism in hypertrophied rat hearts. Myocardial hypertrophy was produced by partial occlusion of the suprarenal aorta of juvenile rats. Over a subsequent 8-week period, a mild hypertrophy developed, resulting in a 17% increase in heart weight in these animals compared with the sham-operated control animals. Myocardial carnitine was decreased in hypertrophied hearts compared with hearts from sham-operated animals (4155±383 versus 5924±570 nmol · g dry wt −1 , respectively; P ≤.05). Perfusion of isolated working hearts for 60 minutes with buffer containing 1 mmol/L PLC increased carnitine content in hypertrophied hearts from 4155±383 to 7081±729 nmol · g dry wt −1 ( P ≤.05). In the presence of 1.2 mmol/L palmitate, fatty acid oxidation rates were not decreased in the hypertrophied hearts compared with control hearts. PLC treatment did not alter rates of fatty acid oxidation in control hearts but did result in a small increase in rates in the hypertrophied hearts. The most dramatic effect of PLC treatment in hypertrophied hearts was an increase in glucose oxidation rates from 137±25 to 627±110 nmol · min −1 · g dry wt −1 ( P ≤.05) and an increase in lactate oxidation rates from 119±17 to 252±47 nmol · min −1 · g dry wt −1 ( P ≤.05). Glycolytic rates, which were already significantly elevated in hypertrophied hearts compared with control hearts, were not altered by PLC treatment. Overall ATP production from exogenous sources was increased by 64% in PLC-treated hypertrophic hearts and was accompanied by a significant increase in cardiac work. The main effect of PLC treatment was to increase the contribution of glucose oxidation to the relative rate of ATP production from 11.6% to 21.6%. The contribution of glucose and palmitate oxidation to ATP production was also determined in aortic-banded animals treated with 60 mg/kg PLC for an 8-week period. This treatment was also associated with a significant improvement in mechanical function in hearts isolated from these animals compared with untreated animals as well as an increase in the contribution of glucose oxidation to ATP production. Despite this improvement of cardiac work after chronic PLC treatment, no increase in palmitate oxidation was observed in hypertrophied hearts. These findings indicate that the beneficial effects of PLC in hypertrophied hearts can be accounted for by a stimulation of ATP production from carbohydrate oxidation rather than from fatty acid oxidation. The increase in carbohydrate oxidation may be a consequence of activation of the pyruvate dehydrogenase complex, by means of a reduction in the ratio of intramitochondrial acetyl coenzyme A to coenzyme A.

Research paper thumbnail of Molecular cloning of chicken calcyclin (S100A6) and identification of putative isoforms

Biochemistry and Cell Biology, 1997

A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, usi... more A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, using reverse transcription - polymerase chain reaction techniques. The deduced amino acid sequence contains 92 residues with 12 substitutions and a 2 amino acid C-terminal extension when compared with human calcyclin. Calcyclin was purified from chicken gizzard by Ca2+-dependent hydrophobic chromatography, heat treatment, and anion-exchange chromatography. N-terminal sequencing of two CNBr peptides confirmed its identity as calcyclin. Two isoforms of calcyclin (A and B), which differ with respect to the presence or absence of a C-terminal lysine, were identified and the native protein was shown to exist as noncovalently associated homodimers (AA and BB) and heterodimers (AB). Incubation of purified calcyclin AA with an extract of chicken gizzard did not result in degradation of calcyclin A or appearance of calcyclin B, suggesting that calcyclin B is a bona fide isoform rather than a proteolytic fragment generated during purification. Western blotting of chicken tissues with anti-(gizzard calcyclin) indicated abundant expression of calcyclin in smooth muscle tissues, including esophagus, large intestine, and trachea, with lower levels in lung, heart, kidney, and brain, and none detectable in liver or skeletal muscle.Key words: Ca2+-binding proteins, calcyclin, smooth muscle, cDNA cloning, isoforms.

Research paper thumbnail of Lopaschuk G. Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts

Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts. Am... more Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts. Am. J. Physiol. 267 (Heart Circ. Physiol. 36): H742-H750, 1994.-The contribu-tion of glycolysis and oxidative metabolism to ATE) production was determined in isolated working hypertrophied hearts perfused with Krebs-Henseleit buffer containing 3 % albumin, 0.4 mM palmitate, 0.5 mM lactate, and 11 mM glucose. Glycolysis and glucose oxidation were directly measured by perfusing hearts with [5-3H/U-14C]glucose and by measuring “Hz0 and 14C02 production, respectively. Palmitate and lac-tate oxidation were determined by simultaneous measurement of “Hz0 and 14COz in hearts perfused with [9,10-3H]palmitate and [U-14C]lactate. At low workloads (60 mmHg aortic after-load), rates of palmitate oxidation were 47 % lower in hypertro-phied hearts than in control hearts, but palmitate oxidation

Research paper thumbnail of Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts

American Journal of Physiology-Heart and Circulatory Physiology, 1994

The contribution of glycolysis and oxidative metabolism to ATP production was determined in isola... more The contribution of glycolysis and oxidative metabolism to ATP production was determined in isolated working hypertrophied hearts perfused with Krebs-Henseleit buffer containing 3% albumin, 0.4 mM palmitate, 0.5 mM lactate, and 11 mM glucose. Glycolysis and glucose oxidation were directly measured by perfusing hearts with [5–3H/U-14C]glucose and by measuring 3H2O and 14CO2 production, respectively. Palmitate and lactate oxidation were determined by simultaneous measurement of 3H2O and 14CO2 in hearts perfused with [9,10–3H]palmitate and [U-14C]lactate. At low workloads (60 mmHg aortic after-load), rates of palmitate oxidation were 47% lower in hypertrophied hearts than in control hearts, but palmitate oxidation remained the primary energy source in both groups, accounting for 55 and 69% of total ATP production, respectively. The contribution of glycolysis to ATP production was significantly higher in hypertrophied hearts (19%) than in control hearts (7%), whereas that of glucose and...

Research paper thumbnail of Regulation of fatty acid oxidation in the mammalian heart in health and disease

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1994

Research paper thumbnail of Calcium regulation of glycolysis, glucose oxidation and fatty acid oxidation in the aerobic and ischemic heart

Canadian Journal of Physiology and Pharmacology, 1995

Although Ca2+is an important regulator of energy metabolism, the effects of increasing extracellu... more Although Ca2+is an important regulator of energy metabolism, the effects of increasing extracellular [Ca2+] on energy substrate preference are not clear. We determined the relationship between [Ca2+], fatty acids, and ischemia on rates of glycolysis, glucose oxidation, and palmitate oxidation in isolated working rat hearts. Hearts were perfused with Krebs–Henseleit buffer containing 11 mM glucose, 100 μU/mL insulin, and either 1.25 or 2.5 mM Ca2+, in the presence or absence of 1.2 mM palmitate. Rates of glycolysis and glucose oxidation or palmitate oxidation were measured in the hearts using [5-3H,14C(U)]glucose or [1-14C]palmitate, respectively. In the absence of fatty acids, glycolysis and glucose oxidation rates were similar, regardless of whether [Ca2+] was 1.25 or 2.5 mM. Addition of 1.2 mM palmitate to the perfusate of hearts perfused with 1.25 mM Ca2+significantly decreased rates of both glycolysis (from 4623 ± 438 to 1378 ± 238 nmol∙min−1∙g−1dry weight) and glucose oxidation...

Research paper thumbnail of Stem Cell Mobilization With HYC750

Biology of Blood and Marrow Transplantation, 2010

Research paper thumbnail of Propionyl-carnitine improvement of hypertrophied rat heart function is associated with an increase in cardiac efficiency

European journal of …, 1995

... Ingwall, JS, 1984, The hypertrophied myocardium accumulates the MBcreatine kinase isozyme, Eu... more ... Ingwall, JS, 1984, The hypertrophied myocardium accumulates the MBcreatine kinase isozyme, Eur. ... King, MT, PD Reiss and NW Cornell, 1988, Determination of shortchain coenzyme A compounds by ... Lysiak, W., K. Lilly, F. Di Lisa, PP Tith and LL Bieber, 1988, Quantification of ...

Research paper thumbnail of Molecular cloning of chicken calcyclin (S100A6) and identification of putative isoforms

Biochemistry and Cell Biology, 1997

A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, usi... more A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, using reverse transcription - polymerase chain reaction techniques. The deduced amino acid sequence contains 92 residues with 12 substitutions and a 2 amino acid C-terminal extension when compared with human calcyclin. Calcyclin was purified from chicken gizzard by Ca2+-dependent hydrophobic chromatography, heat treatment, and anion-exchange chromatography. N-terminal sequencing of two CNBr peptides confirmed its identity as calcyclin. Two isoforms of calcyclin (A and B), which differ with respect to the presence or absence of a C-terminal lysine, were identified and the native protein was shown to exist as noncovalently associated homodimers (AA and BB) and heterodimers (AB). Incubation of purified calcyclin AA with an extract of chicken gizzard did not result in degradation of calcyclin A or appearance of calcyclin B, suggesting that calcyclin B is a bona fide isoform rather than a proteolytic fragment generated during purification. Western blotting of chicken tissues with anti-(gizzard calcyclin) indicated abundant expression of calcyclin in smooth muscle tissues, including esophagus, large intestine, and trachea, with lower levels in lung, heart, kidney, and brain, and none detectable in liver or skeletal muscle.Key words: Ca2+-binding proteins, calcyclin, smooth muscle, cDNA cloning, isoforms.

Research paper thumbnail of HYC750: A Novel Stem Cell Mobilizer

Blood, 2009

3220 Poster Board III-157 Hyaluronic acid (HA) is a repeating disaccharide polymer having various... more 3220 Poster Board III-157 Hyaluronic acid (HA) is a repeating disaccharide polymer having various biological activities depending on size: high molecular weight HA performs structural functions, whereas low molecular weight HA induces systemic cytokine-like effects. HYC750 is a Good Manufacturing Practices (GMP)-generated HA with a maximum molecular weight of 750 kDA that is currently in development as a hematopoietic stem cell mobilizer. Given the potential for proinflammatory activities of various very low MW HA fragments we sought to determine whether HYC750 may possess properties detrimental to clinical use. Dose-dependent administration of HYC750 to bone marrow stromal cells, the monocytic cell line RAW, and differentiated THP-1 cells did not result in alteration of proliferation or viability. Treatment of said cells with HYC750 did not elicit production of TNF-alpha as assessed by the L929 assay. In contrast, LPS treatment induced a dose dependent cytokine response. These data...

Research paper thumbnail of Contribution of Glycogen and Exogenous Glucose to Glucose Metabolism During Ischemia in the Hypertrophied Rat Heart

Circulation Research, Oct 1, 1997

Although hypertrophied hearts have increased rates of glycolysis under aerobic conditions, it is ... more Although hypertrophied hearts have increased rates of glycolysis under aerobic conditions, it is controversial as to whether glucose metabolism during ischemia is altered in the hypertrophied heart. Because endogenous glycogen stores are a key source of glucose during ischemia, we developed a protocol to label the glycogen pool in hearts with either [ 3 H]glucose or [ 14 C]glucose, allowing for direct measurement of both glycogen and exogenous glucose metabolism during ischemia. Cardiac hypertrophy was produced in rats by banding the abdominal aorta for an 8-week period. Isolated hearts from aortic-banded and sham-operated rats were initially perfused under substrate-free conditions to decrease glycogen content to 40% of the initial pool size. Resynthesis and radiolabeling of the glycogen pool with [ 3 H]glucose or [ 14 C]glucose were accomplished in working hearts by perfusion for a 60-minute period with 11 mmol/L [ 3 H]glucose or [ 14 C]glucose, 0.5 mmol/L lactate, 1.2 mmol/L palmitate, and 100 μmol/mL insulin. Although glycolytic rates during the aerobic perfusion were significantly greater in hypertrophied hearts compared with control hearts, glycolytic rates from exogenous glucose were not different during low-flow ischemia. The contribution of glucose from glycogen was also not different in hypertrophied hearts compared with control hearts during ischemia (1314±665 versus 776±310 nmol · min −1 · g dry wt −1 , respectively). Glucose oxidation rates decreased during ischemia but were not different between the two groups. However, in both hypertrophied and control hearts, the ratio of glucose oxidation to glycolysis was greater for glucose originating from glycogen than from exogenous glucose. Our data demonstrate that glycogen is a significant source of glucose during low-flow ischemia, but the data do not differ between hypertrophied and control hearts.

Research paper thumbnail of Letter to the Editor: 1 H, 15 N and 13 C resonance assignments of rabb

Research paper thumbnail of Propionyl l-carnitine improvement of hypertrophied rat heart function is associated with an increase in cardiac efficiency

European Journal of Pharmacology, Nov 14, 1995

Propionyl L-carnitine (PLC) is a naturally occurring derivative of L-carnitine that can improve h... more Propionyl L-carnitine (PLC) is a naturally occurring derivative of L-carnitine that can improve hemodynamic function of hypertrophied rat hearts. The mechanism(s) responsible for the beneficial effects of PLC is not known, although improvement of myocardial energy metabolism has been suggested. In this study, we determined the effect of PLC on carbohydrate and fatty acid metabolism in hypertrophied rat hearts. Myocardial hypertrophy was produced by partial occlusion of the suprarenal aorta of juvenile rats. Over a subsequent 8-week period, a mild hypertrophy developed, resulting in a 17% increase in heart weight in these animals compared with the sham-operated control animals. Myocardial carnitine was decreased in hypertrophied hearts compared with hearts from sham-operated animals (4155 +/- 383 versus 5924 +/- 570 nmol.g dry wt-1, respectively; P &lt; or = .05). Perfusion of isolated working hearts for 60 minutes with buffer containing 1 mmol/L PLC increased carnitine content in hypertrophied hearts from 4155 +/- 383 to 7081 +/- 729 nmol.g dry wt-1 (P &lt; or = .05). In the presence of 1.2 mmol/L palmitate, fatty acid oxidation rates were not decreased in the hypertrophied hearts compared with control hearts. PLC treatment did not alter rates of fatty acid oxidation in control hearts but did result in a small increase in rates in the hypertrophied hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Contribution of Glycogen to Aerobic Myocardial Glucose Utilization

Circulation, Apr 1, 1996

Background We determined glycogen turnover and the contribution of glycogen as a source of glucos... more Background We determined glycogen turnover and the contribution of glycogen as a source of glucose for aerobic myocardial glycolysis and glucose oxidation in parallel series of isolated, working rat hearts subjected to pulse-chase perfusions. Methods and Results Myocardial glycogen of isolated, working rat hearts was radiolabeled, after 30 minutes of substrate-free glycogen depletion, by perfusion for 60 minutes with buffer designed to stimulate resynthesis of glycogen (1.2 mmol/L palmitate, 11 mmol/L [U- 14 C]- or [5- 3 H]-glucose, 0.5 mmol/L lactate, and 100 μU/mL insulin). Rates of glucose oxidation ( 14 CO 2 production) and glycolysis ( 3 H 2 O production) were then measured by perfusing the hearts for 40 minutes with buffer designed to simulate physiological conditions (0.4 mmol/L palmitate, 0.5 mmol/L lactate, 11 mmol/L [5- 3 H]- or [U- 14 C]-glucose, 100 μU/mL insulin) containing radiolabeled glucose different from that used during resynthesis. During the chase perfusion, rates of glycolysis and glucose oxidation from exogenous glucose were significantly greater than those from endogenous glycogen. Nevertheless, glycogen contributed significantly to myocardial energy production (41% of the overall ATP produced from glucose), and a significantly greater fraction of the glucose from glycogen that passed through glycolysis was oxidized (&gt;50%) compared with the fraction oxidized from exogenous glucose (&lt;20%, P

Research paper thumbnail of The effects of carnitine on myocardial carbohydrate metabolism

Developments in Cardiovascular Medicine, 1995

Research paper thumbnail of 1H, 15N and 13C resonance assignments of rabbit apo-S100A11

Journal of biomolecular NMR, 2002

S100 proteins belong to the EF-hand family of calcium binding proteins. Upon calcium binding, the... more S100 proteins belong to the EF-hand family of calcium binding proteins. Upon calcium binding, these proteins undergo a conformational change to expose a hydrophobic region necessary for target protein interaction. One member of the S100 protein family is S100A11, first isolated from chicken gizzard and termed calgizzarin. It was later isolated from other organisms and tissues including human placenta, pig heart and rabbit lung. The physiological target of S100A11 is thought to be annexin I, a phospholipid-binding protein involved in EGF receptor sorting. This work reports the 1H, 15N and 13C resonance assignments of rabbit apo-S100A11 determined using 15N, 13C-labelled protein and multidimensional NMR spectroscopy.

Research paper thumbnail of The importance of glycolysis versus glucose oxidation on rates of mechanical failure of rat hearts subjected to low flow ischemia

Journal of Molecular and Cellular Cardiology, 1992

Myocardial function and glucose utilization was measured in isolated working hearts obtained from... more Myocardial function and glucose utilization was measured in isolated working hearts obtained from partially normoglycemic Wistar Furth rats (blood glucose 118178 mg/dl). Islets ('1200) were transplanted beneath the kidney capsule 2 weeks after a single i.v. dose of streptozotocin (55 mg/kgl. The study consisted of 3 groups; 1) islet-transplanted diabetic rats, 2) untreated diabetic controls, and 3) normal controls. Following 11 weeks of monitoring, working hearts were perfused at a 11.5 mmHg preload and 80 mmHg afterload, with buffer containing 11 mM (5-3H/U-14C)-glucose, 1.2 mM palmitate, and 100 pU/ml insulin. Glycolysis and glucose oxidation fnmol glucose/g dry wtmin), and mechanical function (heart rate x A pressure product) in these hearts is shown below: Control Diabetic Parameter untreated islet-transplants Glycolysis 2720&265 1944&436 1836+242 Glucose Oxidation 51&68 XX4 23&39' HRxAP 4.8&l .3 1 .6ti.9 4 .8+1.5' t, significantly different than untreated diabetics The data supports our previous data, which suggests that increasing glucose oxidation can improve function in diabetic rat hearts.

Research paper thumbnail of Energy metabolism in the hypertrophied heart

Research paper thumbnail of Regulation of fatty acid oxidation in the mammalian heart in health and disease

Biochimica et biophysica acta, Aug 1, 1994

Research paper thumbnail of Recovery of glycolysis and oxidative metabolism during postischemic reperfusion of hypertrophied rat hearts

American Journal of Physiology-heart and Circulatory Physiology, Aug 1, 1996

We investigated the source and extent of recovery of ATP production during postischemic reperfusi... more We investigated the source and extent of recovery of ATP production during postischemic reperfusion of isolated working hearts from abdominal aortic-banded rats. Rates of glycolysis, glucose oxidation, lactate oxidation, and palmitate oxidation were measured in hypertrophied and control hearts [perfused with (in mM) 11 glucose, 0.5 lactate, and 1.2 palmitate] during and after 30 min of no-flow ischemia. In the initial aerobic period glycolytic rates were 1.87-fold higher in hypertrophied hearts compared with control hearts (P &lt; 0.05), with rates of carbohydrate and palmitate oxidation being similar. During reperfusion, hypertrophied hearts recovered 40% of preischemic function compared with 71% in control hearts. Rates of glycolysis during reperfusion of hypertrophied hearts remained accelerated compared with control hearts (2.01-fold higher, P &lt; 0.05), whereas oxidative metabolism returned to preischemic values in both groups. The efficiency of converting ATP production into mechanical work decreased to 29% of preischemic values in hypertrophied hearts during the postischemic reperfusion compared with a decrease to only 59% of preischemic values in control hearts. This suggests that the recovery of glycolysis and oxidative metabolism in the hypertrophied heart during postischemic reperfusion is not impaired, but rather the efficiency of converting ATP produced into mechanical function decreases.

Research paper thumbnail of Propionyl <scp>l</scp> -Carnitine Improvement of Hypertrophied Heart Function Is Accompanied by an Increase in Carbohydrate Oxidation

Circulation Research, Oct 1, 1995

Propionyl l -carnitine (PLC) is a naturally occurring derivative of l -carnitine that can improve... more Propionyl l -carnitine (PLC) is a naturally occurring derivative of l -carnitine that can improve hemodynamic function of hypertrophied rat hearts. The mechanism(s) responsible for the beneficial effects of PLC is not known, although improvement of myocardial energy metabolism has been suggested. In this study, we determined the effect of PLC on carbohydrate and fatty acid metabolism in hypertrophied rat hearts. Myocardial hypertrophy was produced by partial occlusion of the suprarenal aorta of juvenile rats. Over a subsequent 8-week period, a mild hypertrophy developed, resulting in a 17% increase in heart weight in these animals compared with the sham-operated control animals. Myocardial carnitine was decreased in hypertrophied hearts compared with hearts from sham-operated animals (4155±383 versus 5924±570 nmol · g dry wt −1 , respectively; P ≤.05). Perfusion of isolated working hearts for 60 minutes with buffer containing 1 mmol/L PLC increased carnitine content in hypertrophied hearts from 4155±383 to 7081±729 nmol · g dry wt −1 ( P ≤.05). In the presence of 1.2 mmol/L palmitate, fatty acid oxidation rates were not decreased in the hypertrophied hearts compared with control hearts. PLC treatment did not alter rates of fatty acid oxidation in control hearts but did result in a small increase in rates in the hypertrophied hearts. The most dramatic effect of PLC treatment in hypertrophied hearts was an increase in glucose oxidation rates from 137±25 to 627±110 nmol · min −1 · g dry wt −1 ( P ≤.05) and an increase in lactate oxidation rates from 119±17 to 252±47 nmol · min −1 · g dry wt −1 ( P ≤.05). Glycolytic rates, which were already significantly elevated in hypertrophied hearts compared with control hearts, were not altered by PLC treatment. Overall ATP production from exogenous sources was increased by 64% in PLC-treated hypertrophic hearts and was accompanied by a significant increase in cardiac work. The main effect of PLC treatment was to increase the contribution of glucose oxidation to the relative rate of ATP production from 11.6% to 21.6%. The contribution of glucose and palmitate oxidation to ATP production was also determined in aortic-banded animals treated with 60 mg/kg PLC for an 8-week period. This treatment was also associated with a significant improvement in mechanical function in hearts isolated from these animals compared with untreated animals as well as an increase in the contribution of glucose oxidation to ATP production. Despite this improvement of cardiac work after chronic PLC treatment, no increase in palmitate oxidation was observed in hypertrophied hearts. These findings indicate that the beneficial effects of PLC in hypertrophied hearts can be accounted for by a stimulation of ATP production from carbohydrate oxidation rather than from fatty acid oxidation. The increase in carbohydrate oxidation may be a consequence of activation of the pyruvate dehydrogenase complex, by means of a reduction in the ratio of intramitochondrial acetyl coenzyme A to coenzyme A.

Research paper thumbnail of Molecular cloning of chicken calcyclin (S100A6) and identification of putative isoforms

Biochemistry and Cell Biology, 1997

A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, usi... more A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, using reverse transcription - polymerase chain reaction techniques. The deduced amino acid sequence contains 92 residues with 12 substitutions and a 2 amino acid C-terminal extension when compared with human calcyclin. Calcyclin was purified from chicken gizzard by Ca2+-dependent hydrophobic chromatography, heat treatment, and anion-exchange chromatography. N-terminal sequencing of two CNBr peptides confirmed its identity as calcyclin. Two isoforms of calcyclin (A and B), which differ with respect to the presence or absence of a C-terminal lysine, were identified and the native protein was shown to exist as noncovalently associated homodimers (AA and BB) and heterodimers (AB). Incubation of purified calcyclin AA with an extract of chicken gizzard did not result in degradation of calcyclin A or appearance of calcyclin B, suggesting that calcyclin B is a bona fide isoform rather than a proteolytic fragment generated during purification. Western blotting of chicken tissues with anti-(gizzard calcyclin) indicated abundant expression of calcyclin in smooth muscle tissues, including esophagus, large intestine, and trachea, with lower levels in lung, heart, kidney, and brain, and none detectable in liver or skeletal muscle.Key words: Ca2+-binding proteins, calcyclin, smooth muscle, cDNA cloning, isoforms.

Research paper thumbnail of Lopaschuk G. Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts

Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts. Am... more Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts. Am. J. Physiol. 267 (Heart Circ. Physiol. 36): H742-H750, 1994.-The contribu-tion of glycolysis and oxidative metabolism to ATE) production was determined in isolated working hypertrophied hearts perfused with Krebs-Henseleit buffer containing 3 % albumin, 0.4 mM palmitate, 0.5 mM lactate, and 11 mM glucose. Glycolysis and glucose oxidation were directly measured by perfusing hearts with [5-3H/U-14C]glucose and by measuring “Hz0 and 14C02 production, respectively. Palmitate and lac-tate oxidation were determined by simultaneous measurement of “Hz0 and 14COz in hearts perfused with [9,10-3H]palmitate and [U-14C]lactate. At low workloads (60 mmHg aortic after-load), rates of palmitate oxidation were 47 % lower in hypertro-phied hearts than in control hearts, but palmitate oxidation

Research paper thumbnail of Contribution of oxidative metabolism and glycolysis to ATP production in hypertrophied hearts

American Journal of Physiology-Heart and Circulatory Physiology, 1994

The contribution of glycolysis and oxidative metabolism to ATP production was determined in isola... more The contribution of glycolysis and oxidative metabolism to ATP production was determined in isolated working hypertrophied hearts perfused with Krebs-Henseleit buffer containing 3% albumin, 0.4 mM palmitate, 0.5 mM lactate, and 11 mM glucose. Glycolysis and glucose oxidation were directly measured by perfusing hearts with [5–3H/U-14C]glucose and by measuring 3H2O and 14CO2 production, respectively. Palmitate and lactate oxidation were determined by simultaneous measurement of 3H2O and 14CO2 in hearts perfused with [9,10–3H]palmitate and [U-14C]lactate. At low workloads (60 mmHg aortic after-load), rates of palmitate oxidation were 47% lower in hypertrophied hearts than in control hearts, but palmitate oxidation remained the primary energy source in both groups, accounting for 55 and 69% of total ATP production, respectively. The contribution of glycolysis to ATP production was significantly higher in hypertrophied hearts (19%) than in control hearts (7%), whereas that of glucose and...

Research paper thumbnail of Regulation of fatty acid oxidation in the mammalian heart in health and disease

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1994

Research paper thumbnail of Calcium regulation of glycolysis, glucose oxidation and fatty acid oxidation in the aerobic and ischemic heart

Canadian Journal of Physiology and Pharmacology, 1995

Although Ca2+is an important regulator of energy metabolism, the effects of increasing extracellu... more Although Ca2+is an important regulator of energy metabolism, the effects of increasing extracellular [Ca2+] on energy substrate preference are not clear. We determined the relationship between [Ca2+], fatty acids, and ischemia on rates of glycolysis, glucose oxidation, and palmitate oxidation in isolated working rat hearts. Hearts were perfused with Krebs–Henseleit buffer containing 11 mM glucose, 100 μU/mL insulin, and either 1.25 or 2.5 mM Ca2+, in the presence or absence of 1.2 mM palmitate. Rates of glycolysis and glucose oxidation or palmitate oxidation were measured in the hearts using [5-3H,14C(U)]glucose or [1-14C]palmitate, respectively. In the absence of fatty acids, glycolysis and glucose oxidation rates were similar, regardless of whether [Ca2+] was 1.25 or 2.5 mM. Addition of 1.2 mM palmitate to the perfusate of hearts perfused with 1.25 mM Ca2+significantly decreased rates of both glycolysis (from 4623 ± 438 to 1378 ± 238 nmol∙min−1∙g−1dry weight) and glucose oxidation...

Research paper thumbnail of Stem Cell Mobilization With HYC750

Biology of Blood and Marrow Transplantation, 2010

Research paper thumbnail of Propionyl-carnitine improvement of hypertrophied rat heart function is associated with an increase in cardiac efficiency

European journal of …, 1995

... Ingwall, JS, 1984, The hypertrophied myocardium accumulates the MBcreatine kinase isozyme, Eu... more ... Ingwall, JS, 1984, The hypertrophied myocardium accumulates the MBcreatine kinase isozyme, Eur. ... King, MT, PD Reiss and NW Cornell, 1988, Determination of shortchain coenzyme A compounds by ... Lysiak, W., K. Lilly, F. Di Lisa, PP Tith and LL Bieber, 1988, Quantification of ...

Research paper thumbnail of Molecular cloning of chicken calcyclin (S100A6) and identification of putative isoforms

Biochemistry and Cell Biology, 1997

A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, usi... more A full-length cDNA encoding smooth muscle calcyclin (S100A6) was cloned from chicken gizzard, using reverse transcription - polymerase chain reaction techniques. The deduced amino acid sequence contains 92 residues with 12 substitutions and a 2 amino acid C-terminal extension when compared with human calcyclin. Calcyclin was purified from chicken gizzard by Ca2+-dependent hydrophobic chromatography, heat treatment, and anion-exchange chromatography. N-terminal sequencing of two CNBr peptides confirmed its identity as calcyclin. Two isoforms of calcyclin (A and B), which differ with respect to the presence or absence of a C-terminal lysine, were identified and the native protein was shown to exist as noncovalently associated homodimers (AA and BB) and heterodimers (AB). Incubation of purified calcyclin AA with an extract of chicken gizzard did not result in degradation of calcyclin A or appearance of calcyclin B, suggesting that calcyclin B is a bona fide isoform rather than a proteolytic fragment generated during purification. Western blotting of chicken tissues with anti-(gizzard calcyclin) indicated abundant expression of calcyclin in smooth muscle tissues, including esophagus, large intestine, and trachea, with lower levels in lung, heart, kidney, and brain, and none detectable in liver or skeletal muscle.Key words: Ca2+-binding proteins, calcyclin, smooth muscle, cDNA cloning, isoforms.

Research paper thumbnail of HYC750: A Novel Stem Cell Mobilizer

Blood, 2009

3220 Poster Board III-157 Hyaluronic acid (HA) is a repeating disaccharide polymer having various... more 3220 Poster Board III-157 Hyaluronic acid (HA) is a repeating disaccharide polymer having various biological activities depending on size: high molecular weight HA performs structural functions, whereas low molecular weight HA induces systemic cytokine-like effects. HYC750 is a Good Manufacturing Practices (GMP)-generated HA with a maximum molecular weight of 750 kDA that is currently in development as a hematopoietic stem cell mobilizer. Given the potential for proinflammatory activities of various very low MW HA fragments we sought to determine whether HYC750 may possess properties detrimental to clinical use. Dose-dependent administration of HYC750 to bone marrow stromal cells, the monocytic cell line RAW, and differentiated THP-1 cells did not result in alteration of proliferation or viability. Treatment of said cells with HYC750 did not elicit production of TNF-alpha as assessed by the L929 assay. In contrast, LPS treatment induced a dose dependent cytokine response. These data...

Research paper thumbnail of Contribution of Glycogen and Exogenous Glucose to Glucose Metabolism During Ischemia in the Hypertrophied Rat Heart

Circulation Research, Oct 1, 1997

Although hypertrophied hearts have increased rates of glycolysis under aerobic conditions, it is ... more Although hypertrophied hearts have increased rates of glycolysis under aerobic conditions, it is controversial as to whether glucose metabolism during ischemia is altered in the hypertrophied heart. Because endogenous glycogen stores are a key source of glucose during ischemia, we developed a protocol to label the glycogen pool in hearts with either [ 3 H]glucose or [ 14 C]glucose, allowing for direct measurement of both glycogen and exogenous glucose metabolism during ischemia. Cardiac hypertrophy was produced in rats by banding the abdominal aorta for an 8-week period. Isolated hearts from aortic-banded and sham-operated rats were initially perfused under substrate-free conditions to decrease glycogen content to 40% of the initial pool size. Resynthesis and radiolabeling of the glycogen pool with [ 3 H]glucose or [ 14 C]glucose were accomplished in working hearts by perfusion for a 60-minute period with 11 mmol/L [ 3 H]glucose or [ 14 C]glucose, 0.5 mmol/L lactate, 1.2 mmol/L palmitate, and 100 μmol/mL insulin. Although glycolytic rates during the aerobic perfusion were significantly greater in hypertrophied hearts compared with control hearts, glycolytic rates from exogenous glucose were not different during low-flow ischemia. The contribution of glucose from glycogen was also not different in hypertrophied hearts compared with control hearts during ischemia (1314±665 versus 776±310 nmol · min −1 · g dry wt −1 , respectively). Glucose oxidation rates decreased during ischemia but were not different between the two groups. However, in both hypertrophied and control hearts, the ratio of glucose oxidation to glycolysis was greater for glucose originating from glycogen than from exogenous glucose. Our data demonstrate that glycogen is a significant source of glucose during low-flow ischemia, but the data do not differ between hypertrophied and control hearts.

Research paper thumbnail of Letter to the Editor: 1 H, 15 N and 13 C resonance assignments of rabb

Research paper thumbnail of Propionyl l-carnitine improvement of hypertrophied rat heart function is associated with an increase in cardiac efficiency

European Journal of Pharmacology, Nov 14, 1995

Propionyl L-carnitine (PLC) is a naturally occurring derivative of L-carnitine that can improve h... more Propionyl L-carnitine (PLC) is a naturally occurring derivative of L-carnitine that can improve hemodynamic function of hypertrophied rat hearts. The mechanism(s) responsible for the beneficial effects of PLC is not known, although improvement of myocardial energy metabolism has been suggested. In this study, we determined the effect of PLC on carbohydrate and fatty acid metabolism in hypertrophied rat hearts. Myocardial hypertrophy was produced by partial occlusion of the suprarenal aorta of juvenile rats. Over a subsequent 8-week period, a mild hypertrophy developed, resulting in a 17% increase in heart weight in these animals compared with the sham-operated control animals. Myocardial carnitine was decreased in hypertrophied hearts compared with hearts from sham-operated animals (4155 +/- 383 versus 5924 +/- 570 nmol.g dry wt-1, respectively; P &lt; or = .05). Perfusion of isolated working hearts for 60 minutes with buffer containing 1 mmol/L PLC increased carnitine content in hypertrophied hearts from 4155 +/- 383 to 7081 +/- 729 nmol.g dry wt-1 (P &lt; or = .05). In the presence of 1.2 mmol/L palmitate, fatty acid oxidation rates were not decreased in the hypertrophied hearts compared with control hearts. PLC treatment did not alter rates of fatty acid oxidation in control hearts but did result in a small increase in rates in the hypertrophied hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Contribution of Glycogen to Aerobic Myocardial Glucose Utilization

Circulation, Apr 1, 1996

Background We determined glycogen turnover and the contribution of glycogen as a source of glucos... more Background We determined glycogen turnover and the contribution of glycogen as a source of glucose for aerobic myocardial glycolysis and glucose oxidation in parallel series of isolated, working rat hearts subjected to pulse-chase perfusions. Methods and Results Myocardial glycogen of isolated, working rat hearts was radiolabeled, after 30 minutes of substrate-free glycogen depletion, by perfusion for 60 minutes with buffer designed to stimulate resynthesis of glycogen (1.2 mmol/L palmitate, 11 mmol/L [U- 14 C]- or [5- 3 H]-glucose, 0.5 mmol/L lactate, and 100 μU/mL insulin). Rates of glucose oxidation ( 14 CO 2 production) and glycolysis ( 3 H 2 O production) were then measured by perfusing the hearts for 40 minutes with buffer designed to simulate physiological conditions (0.4 mmol/L palmitate, 0.5 mmol/L lactate, 11 mmol/L [5- 3 H]- or [U- 14 C]-glucose, 100 μU/mL insulin) containing radiolabeled glucose different from that used during resynthesis. During the chase perfusion, rates of glycolysis and glucose oxidation from exogenous glucose were significantly greater than those from endogenous glycogen. Nevertheless, glycogen contributed significantly to myocardial energy production (41% of the overall ATP produced from glucose), and a significantly greater fraction of the glucose from glycogen that passed through glycolysis was oxidized (&gt;50%) compared with the fraction oxidized from exogenous glucose (&lt;20%, P

Research paper thumbnail of The effects of carnitine on myocardial carbohydrate metabolism

Developments in Cardiovascular Medicine, 1995

Research paper thumbnail of 1H, 15N and 13C resonance assignments of rabbit apo-S100A11

Journal of biomolecular NMR, 2002

S100 proteins belong to the EF-hand family of calcium binding proteins. Upon calcium binding, the... more S100 proteins belong to the EF-hand family of calcium binding proteins. Upon calcium binding, these proteins undergo a conformational change to expose a hydrophobic region necessary for target protein interaction. One member of the S100 protein family is S100A11, first isolated from chicken gizzard and termed calgizzarin. It was later isolated from other organisms and tissues including human placenta, pig heart and rabbit lung. The physiological target of S100A11 is thought to be annexin I, a phospholipid-binding protein involved in EGF receptor sorting. This work reports the 1H, 15N and 13C resonance assignments of rabbit apo-S100A11 determined using 15N, 13C-labelled protein and multidimensional NMR spectroscopy.

Research paper thumbnail of The importance of glycolysis versus glucose oxidation on rates of mechanical failure of rat hearts subjected to low flow ischemia

Journal of Molecular and Cellular Cardiology, 1992

Myocardial function and glucose utilization was measured in isolated working hearts obtained from... more Myocardial function and glucose utilization was measured in isolated working hearts obtained from partially normoglycemic Wistar Furth rats (blood glucose 118178 mg/dl). Islets ('1200) were transplanted beneath the kidney capsule 2 weeks after a single i.v. dose of streptozotocin (55 mg/kgl. The study consisted of 3 groups; 1) islet-transplanted diabetic rats, 2) untreated diabetic controls, and 3) normal controls. Following 11 weeks of monitoring, working hearts were perfused at a 11.5 mmHg preload and 80 mmHg afterload, with buffer containing 11 mM (5-3H/U-14C)-glucose, 1.2 mM palmitate, and 100 pU/ml insulin. Glycolysis and glucose oxidation fnmol glucose/g dry wtmin), and mechanical function (heart rate x A pressure product) in these hearts is shown below: Control Diabetic Parameter untreated islet-transplants Glycolysis 2720&265 1944&436 1836+242 Glucose Oxidation 51&68 XX4 23&39' HRxAP 4.8&l .3 1 .6ti.9 4 .8+1.5' t, significantly different than untreated diabetics The data supports our previous data, which suggests that increasing glucose oxidation can improve function in diabetic rat hearts.