bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperbaric oxygen solution infused into the anterior interventricular vein at reperfusion reduces infarct size in swine
Authors: Johnson Lynne L. , Schofield Lorraine , Bouchard Mark , Chaves Leonard , Poppas Athena , Reinert Steven , Zalesky Paul , Creech Jeffrey , Williams David O.
Published: June 2004

This study was designed to test the hypothesis that raising myocardial O2 via diffusion of a hyperbaric oxygen solution (AO) administered through the anterior interventricular vein (AIV) will reduce infarct size by reducing reperfusion injury associated with reduced neutrophil activation. In three pilot open-chest swine experiments, myocardial tissue Po2 was monitored using an oxygen probe during coronary occlusion (Occl) and reperfusion (Rep). One control experiment had no AIV infusion; a second control received arterial blood drawn from the femoral artery infused into the AIV during Rep. In a third open-chest experiment, AO mixed with arterial blood was infused through the AIV at Rep. In controls, tissue Po2 in the risk region (RR) rose early in Rep and then fell to Occl levels, whereas in AO-treated animals, myocardial Po2 remained above baseline. The following three groups of five swine then underwent 60 min of left anterior descending coronary artery Occl and Rep: 1) arterial blood infused at Rep as controls (Con), 2) AO infused beginning 30 min after Rep (AO 30 min), and 3) AO infused immediately at Rep (AO 0 min). There were no differences among the three groups in hemodynamics or myocardial blood flow during baseline (BL) or Occl or in RR size. However, endocardial blood flow was significantly higher in RR during Rep in AO 0 min vs. control and AO 30 min ( P = 0.01). Both infarct size (IS) as %heart and IS as %RR were lower in AO 0 min compared with Con and AO 30 min ( P < 0.01 for both), and myeloperoxidase values were lower for epicardial ( P < 0.001), midmyocardial ( P = 0.03), and endocardial ( P < 0.001) layers in AO 0 min. AO infused into the AIV immediately at Rep diffuses into the RR and reduces IS by reducing Rep injury associated with neutrophil activation.
Expression of genes participating in regulation of fatty acid and glucose utilization and energy metabolism in developing rat hearts
Authors: Lavrentyev Eduard N. , He Daifen , Cook George A.
Published: June 2004

The heart is a unique organ that can use several fuels for energy production. During development, the heart undergoes changes in fuel supply, and it must be able to respond to these changes. We have examined changes in the expression of several genes that regulate fuel transport and metabolism in rat hearts during early development. At birth, there was increased expression of fatty acid transporters and enzymes of fatty acid metabolism that allow fatty acids to become the major source of energy for cardiac muscle during the first 2 wk of life. At the same time, expression of genes that control glucose transport and oxidation was downregulated. After 2 wk, expression of genes for glucose uptake and oxidation was increased, and expression of genes for fatty acid uptake and utilization was decreased. Expression of carnitine palmitoyltransferase I (CPT I) isoforms during development was different from published data obtained from rabbit hearts. CPT Iα and Iβ isoforms were both highly expressed in hearts before birth, and both increased further at birth. Only after the second week did CPT Iα expression decrease appreciably below the level of CPT Iβ expression. These results represent another example of different expression patterns of CPT I isoforms among various mammalian species. In rats, changes in gene expression followed nutrient availability during development and may render cardiac fatty acid oxidation less sensitive to factors that influence malonyl-CoA content (e.g., fluctuations in glucose concentration) and thereby favor fatty acid oxidation as an energy source for cardiomyocytes in early development.
Duration of diastole and its phases as a function of heart rate during supine bicycle exercise
Authors: Chung Charles S. , Karamanoglu Mustafa , Kovács Sándor J.
Published: June 2004

The duration of diastole can be defined in terms of mechanical events. Mechanical diastolic duration (MDD) is comprised by the phases of early rapid filling (E wave), diastasis, and late atrial filling (A wave). The effect of heart rate (HR) on diastolic duration is predictable from kinematic modeling and known cellular physiology. To determine the dependence of MDD of each phase and the velocity time integral (VTI) on HR, simultaneous transmitral Doppler flow velocities and ECG were recorded during supine bicycle exercise in healthy volunteers. Durations, peak values, and VTI using triangular approximation for E- and A-wave shape were measured. MDD, defined as the interval from the start of the E wave to end of the A wave, was fit as an algebraic function of HR by MDD = BMDD + MLMDD·HR + MIMDD/HR, derivable from first principles, where BMDD is a constant, and MLMDD and MIMDD are the constant coefficients of the linear and inverse HR dependent terms. Excellent correlation was observed ( r2 = 0.98). E- and A-wave durations were found to be very nearly independent of HR: 100% increase in HR generated only an 18% decrease in E-wave duration and 16% decrease in A-wave duration. VTI was similarly very nearly independent of HR. Diastasis duration closely tracked MDD as a function of HR. We conclude that the elimination of diastasis and merging of E and A waves of nearly fixed durations primarily govern changes in MDD. These observations support the perspective that E- and A-wave durations are primarily governed by the rules of mechanical oscillation that are minimally HR dependent.
Persistent twenty-four hour changes in liver and bone marrow despite suprachiasmatic nuclei ablation in mice
Authors: Filipski Elisabeth , King Verdun M. , Etienne Marie-Christine , Li XiaoMei , Claustrat Bruno , Granda Teresa G. , Milano Gérard , Hastings Michael H. , Lévi Francis
Published: June 2004

Rest-activity or cortisol rhythms can be altered in cancer patients, a condition that may impair the benefits from a timed delivery of anticancer treatments. In rodents, the circadian pattern in rest-activity is suppressed by the destruction of the suprachiasmatic nuclei (SCN) in the hypothalamus. We sought whether such ablation would result in a similar alteration of cellular rhythms known to be relevant for anticancer drug chronopharmacology. The SCN of 77 B6D2F1mice synchronized with 12 h of light and 12 h of darkness were destroyed by electrocoagulation [SCN(−)], while 34 animals were sham operated. Activity and body temperature were recorded by telemetry. Blood and organs were sampled at one of six circadian times for determinations of serum corticosterone concentration, blood leukocyte count, reduced glutathione (GSH), and dihydropyrimidine dehydrogenase (DPD) mRNA expression in liver and cell cycle phase distribution of bone marrow cells. Sham-operated mice displayed significant 24-h rhythms in rest-activity and body temperature, whereas such rhythms were found in none and in 15% of the SCN(−) mice, respectively. SCN lesions markedly altered the rhythmic patterns in serum corticosterone and liver GSH, which became nonsinusoidal. Liver DPD mRNA expression and bone marrow cell cycle phase distribution displayed similar 24-h sinusoidal patterns in sham-operated and SCN(−) mice. These results support the existence of another light-dark entrainable pacemaker that can coordinate cellular functions in peripheral organs. They suggest that the delivery of anticancer treatments at an optimal time of day may still be beneficial, despite suppressed rest-activity or cortisol rhythms.
Selective deficits in the circadian light response in mice lacking PACAP
Authors: Colwell C. S. , Michel S. , Itri J. , Rodriguez W. , Tam J. , Lelièvre V. , Hu Z. , Waschek J. A.
Published: June 2004

Previous studies indicate that light information reaches the suprachiasmatic nucleus through a subpopulation of retinal ganglion cells that contain both glutamate and pituitary adenylyl cyclase-activating peptide (PACAP). Although the role of glutamate in this pathway has been well studied, the involvement of PACAP and its receptors is only beginning to be understood. To investigate the functions of PACAP in vivo, we developed a mouse model in which the gene coding for PACAP was disrupted by targeted homologous recombination. RIA was used to confirm a lack of detectable PACAP protein in these mice. PACAP-deficient mice exhibited significant impairment in the magnitude of the response to brief light exposures with both light-induced phase delays and advances of the circadian system impacted. This mutation equally impacted phase shifts induced by bright and dim light exposure. Despite these effects on phase shifting, the loss of PACAP had only limited effects on the generation of circadian oscillations, as measured by rhythms in wheel-running activity. Unlike melanopsin-deficient mice, the mice lacking PACAP exhibited no loss of function in the direct light-induced inhibition of locomotor activity, i.e., masking. Finally, the PACAP-deficient mice exhibited normal phase shifts in response to exposure to discrete dark treatments. The results reported here show that the loss of PACAP produced selective deficits in the light response of the circadian system.
Age-dependent changes in contraction and regional myocardial myosin heavy chain isoform expression in rats
Authors: Carnes Cynthia A. , Geisbuhler Timothy P. , Reiser Peter J.
Published: June 2004

The goals of this study were to measure the relative levels of the α- and β-isoforms of myosin heavy chain (MHC-α and MHC-β, respectively) in multiple, specific regions of the adult rat heart and to determine whether age-dependent changes in isoform levels in different regions are uniform. Relative amounts of MHC-α and MHC-β were determined in right and left atria and left ventricular (LV) Purkinje fibers (PF), papillary muscles, trabeculae, and endo-, mid-, and epicardial regions at 2, 5, 10, 16, and 21 mo. PFs contained substantial amounts of myosin and were striated and capable of generating force and shortening on activation. Levels of MHC-β increased in all LV compartments with age, especially between 2 and 5 mo. There was more MHC-β in PFs than other LV sites. There were regional differences in the level of MHC-β throughout the LV at all ages, and the rates of change within regions differed. Ca2+-activated tension in PFs and trabeculae was compared at 2 and 22 mo. PF tension was less than trabecula tension, and this difference may be explained by differences in MHC content. Vmax and tension-generating ability in PFs decreased with age. Maximal tension generated by trabeculae did not change during aging. A large proportion of the increase in the level of MHC-β that is normally associated with aging occurs at a relatively early age in rat LV. PFs, with their small diameters and short diffusion distance, should be considered for skinned multicellular myocardial studies.
Resistance exercise as a countermeasure to disuse-induced bone loss
Authors: Shackelford L. C. , LeBlanc A. D. , Driscoll T. B. , Evans H. J. , Rianon N. J. , Smith S. M. , Spector E. , Feeback D. L. , Lai D.
Published: June 2004

During spaceflight, skeletal unloading results in loss of bone mineral density (BMD). This occurs primarily in the spine and lower body regions. This loss of skeletal mass could prove hazardous to astronauts on flights of long duration. In this study, intense resistance exercise was used to test whether a training regimen would prevent the loss of BMD that accompanies disuse. Nine subjects (5 men, 4 women) participated in a supine maximal resistance exercise training program during 17 wk of horizontal bed rest. These subjects were compared with 18 control subjects (13 men, 5 women) who followed the same bed rest protocol without exercise. Determination of treatment effect was based on measures of BMD, bone metabolism markers, and calcium balance obtained before, during, and after bed rest. Exercisers and controls had significantly ( P < 0.05) different means, represented by the respective following percent changes: lumbar spine BMD, +3% vs. −1%; total hip BMD, +1% vs. −3%; calcaneus BMD, +1% vs. −9%; pelvis BMD, −0.5% vs. −3%; total body BMD, 0% vs. −1%; bone-specific alkaline phosphatase, +64% vs. 0%; alkaline phosphatase, +31% vs. +5%; osteocalcin, +43% vs. +10%; 1,25 dihydroxyvitamin D, +12% vs. −15%; parathyroid hormone intact molecule, +18% vs. −25%; and serum and ionized calcium, −1% vs. +1%. The difference in net calcium balance was also significant (+21 mg/day vs. −199 mg/day, exercise vs. control). The gastrocnemius and soleus muscle volumes decreased significantly in the exercise group, but the loss was significantly less than observed in the control group. The results indicate that resistance exercise had a positive treatment effect and thus might be useful as a countermeasure to prevent the deleterious skeletal changes associated with long-duration spaceflight.
Human muscle sarcoplasmic reticulum function during submaximal exercise in normoxia and hypoxia
Authors: Duhamel T. A. , Green H. J. , Perco J. G. , Sandiford S. D. , Ouyang J.
Published: June 2004

In this study, the response of the sarcoplasmic reticulum (SR) to prolonged exercise, performed in normoxia (inspired O2fraction = 0.21) and hypoxia (inspired O2fraction = 0.14) was studied in homogenates prepared from the vastus lateralis muscle in 10 untrained men (peak O2consumption = 3.09 ± 0.25 l/min). In normoxia, performed at 48 ± 2.2% peak O2consumption, maximal Ca2+-dependent ATPase activity was reduced by ∼25% at 30 min of exercise compared with rest (168 ± 10 vs. 126 ± 8 μmol·g protein−1·min−1), with no further reductions observed at 90 min (129 ± 6 μmol·g protein−1·min−1). No changes were observed in the Hill coefficient or in the Ca2+concentration at half-maximal activity. The reduction in maximal Ca2+-dependent ATPase activity at 30 min of exercise was accompanied by oxalate-dependent reductions ( P < 0.05) in Ca2+uptake by ∼20% (370 ± 22 vs. 298 ± 25 μmol·g protein−1·min−1). Ca2+release, induced by 4-chloro- m-cresol and assessed into fast and slow phases, was decreased ( P < 0.05) by ∼16 and ∼32%, respectively, by 90 min of exercise. No differences were found between normoxia and hypoxia for any of the SR properties examined. It is concluded that the disturbances induced in SR Ca2+cycling with prolonged moderate-intensity exercise in human muscle during normoxia are not modified when the exercise is performed in hypoxia.
Stretch-induced ventricular arrhythmias during acute ischemia and reperfusion
Authors: Parker Kevin Kit , Lavelle James A. , Taylor L. Katherine , Wang Zifa , Hansen David E.
Published: June 2004

Mechanical stretch has been demonstrated to have electrophysiological effects on cardiac muscle, including alteration of the probability of excitation, alteration of the action potential waveform, and stretch-induced arrhythmia (SIA). We demonstrate that regional ventricular ischemia due to coronary artery occlusion increases arrhythmogenic effects of transient diastolic stretch, whereas globally ischemic hearts showed no such increase. We tested our hypothesis that, during phase Ia ischemia, regionally ischemic hearts may be more susceptible to triggered arrhythmogenesis due to transient diastolic stretch. During the first 20 min of regional ischemia, the probability of eliciting a ventricular SIA ( PSIA) by transient diastolic stretch increased significantly. However, after 30 min, PSIA decreased to a value comparable with baseline measurements, as expected during phase Ib, where most ventricular arrhythmias are of reentrant mechanisms. We also suggest that mechanoelectrical coupling may contribute to the nonreentrant mechanisms underlying reperfusion-induced arrhythmia. When coronary artery occlusion was relieved after 30 min of ischemia, we observed an increase in PSIA and the maintenance of this elevated level throughout 20 min of reperfusion. We conclude that mechanoelectrical coupling may underlie triggered arrhythmogenesis during phase 1a ischemia and reperfusion.
Matching coronary blood flow to myocardial oxygen consumption
Authors: Tune Johnathan D. , Gorman Mark W. , Feigl Eric O.
Published: June 2004

At rest the myocardium extracts ∼75% of the oxygen delivered by coronary blood flow. Thus there is little extraction reserve when myocardial oxygen consumption is augmented severalfold during exercise. There are local metabolic feedback and sympathetic feedforward control mechanisms that match coronary blood flow to myocardial oxygen consumption. Despite intensive research the local feedback control mechanism remains unknown. Physiological local metabolic control is not due to adenosine, ATP-dependent K+channels, nitric oxide, prostaglandins, or inhibition of endothelin. Adenosine and ATP-dependent K+channels are involved in pathophysiological ischemic or hypoxic coronary dilation and myocardial protection during ischemia. Sympathetic β-adrenoceptor-mediated feedforward arteriolar vasodilation contributes ∼25% of the increase in coronary blood flow during exercise. Sympathetic α-adrenoceptor-mediated vasoconstriction in medium and large coronary arteries during exercise helps maintain blood flow to the vulnerable subendocardium when cardiac contractility, heart rate, and myocardial oxygen consumption are high. In conclusion, several potential mediators of local metabolic control of the coronary circulation have been evaluated without success. More research is needed.
Upper airway afferents are sufficient to evoke the early components of respiratory-related cortical potentials in humans
Authors: Donzel-Raynaud Christine , Straus Christian , Bezzi Michela , Redolfi Stefania , Raux Mathieu , Zelter Marc , Derenne Jean-Philippe , Similowski Thomas
Published: June 2004

Repeated inspiratory occlusions in humans elicit respiratory-related cortical potentials, the respiratory counterpart of somatosensory-evoked potentials. These potentials comprise early components (stimulus detection) and late components (cognitive processing). They are considered as the summation of several afferent activities from various part of the respiratory system. This study assesses the role of the upper airway as a determinant of the early and late components of the potentials, taking advantage of the presence of a tracheotomy in patients totally or partially deafferented. Eight patients who could breathe either through the mouth or through a tracheotomy orifice (whole upper airway bypassed) were studied (4 quadriplegic patients with phrenic pacing, 4 patients with various sources of inspiratory pump dysfunction). Respiratory-related evoked potentials were recorded in CZ-C3 and CZ-C4. They were consistently present after mouth occlusions, with a first positive P1 and a first negative N1 components of normal latencies (P1: 40.4 ± 6.1 ms in CZ-C3 and 47.6 ± 7.6 ms in CZ-C4; N1: 84.4 ± 27.1 ms in CZ-C3 and 90.2 ± 17.4 ms in CZ-C4) and amplitudes. Tracheal occlusions did not evoke any cortical activity. Therefore, in patients with inspiratory pump dysfunction, the activation of upper airway afferents is sufficient to produce the early components of the respiratory-related evoked cortical potentials. Per contra, in this setting, pulmonary afferents do not suffice to evoke these components.
Convergency of the fuzzy vectors in the pseudo‐fuzzy vector space over Fp1(1)
Authors: Wu Kweimei
Published: June 2004

In 2003, we considered the pseudo‐fuzzy vector space SFR over
. Here, we further discuss the convergency of the fuzzy
vectors in SFR.
On long exact (π¯,ExtΛ)‐sequences in module theory
Authors: Su C. Joanna
Published: June 2004

In (2003), we proved the injective homotopy exact
sequence of modules by a method that does not refer to any
elements of the sets in the argument, so that the duality applies
automatically in the projective homotopy theory (of modules)
without further derivation. We inherit this fashion in this paper
during our process of expanding the homotopy exact sequence. We
name the resulting doubly infinite sequence the long exact-sequence in the second variable—it
links the (injective) homotopy exact sequence with the long exact
ExtΛ‐sequence in the second variable through a
connecting term which has a structure containing traces of both a
‐homotopy group and an ExtΛ‐group. We then
demonstrate the nontriviality of the injective/projective
relative homotopy groups (of modules) based on the results ofs
Su (2001). Finally, by inserting three
‐sequences into a one‐of‐a‐kind diagram,
we establish the long exact ‐sequence of
a triple, which is an extension of the homotopy sequence of a
triple in module theory.
Basic Fibroblast Growth Factor Antagonizes Transforming Growth Factor-β1–Induced Smooth Muscle Gene Expression Through Extracellular Signal–Regulated Kinase 1/2 Signaling Pathway Activation
Authors: Kawai-Kowase Keiko , Sato Hiroko , Oyama Yuko , Kanai Hiroyoshi , Sato Mahito , Doi Hiroshi , Kurabayashi Masahiko
Published: June 2004

Objective—

Transforming growth factor-β1 (TGFβ1) and fibroblast growth factor (FGF) families play a pivotal role during vascular development and in the pathogenesis of vascular disease. However, the interaction of intracellular signaling evoked by each of these growth factors is not well understood. The present study was undertaken to examine the molecular mechanisms that mediate the effects of TGFβ1 and basic FGF (bFGF) on smooth muscle cell (SMC) gene expression.

Methods and Results—

TGFβ1 induction of SMC gene expression, including smooth muscle protein 22-α (SM22α) and smooth muscle α-actin, was examined in the pluripotent 10T1/2 cells. Marked increase in these mRNA levels by TGFβ1 was inhibited by c-Src-tyrosine kinase inhibitors and protein synthesis inhibitor cycloheximide. Functional studies with deletion and site-directed mutation analysis of the SM22α promoter demonstrated that TGFβ1 activated the SM22α promoter through a CC(A/T-rich)
6
GG (CArG) box, which serves as a serum response factor (SRF)–binding site. TGFβ1 increased SRF expression through an increase in transcription of the SRF gene. In the presence of bFGF, TGFβ1 induction of SMC marker gene expression was significantly attenuated. Transient transfection assays showed that bFGF significantly suppressed induction of the SM22α promoter–driven luciferase activity by TGFβ1, whereas bFGF had no effects on the TGFβ1-mediated increase in SRF expression and SRF:DNA binding activity. Mitogen-activated protein kinase kinase-1 (MEK1) inhibitor PD98059 abrogated the bFGF-mediated suppression of TGFβ1-induced SMC gene expression.

Conclusion—

Our data suggest that bFGF-induced MEK/extracellular signal-regulated kinase signaling plays an antagonistic role in TGFβ1-induced SMC gene expression through suppression of the SRF function. These data indicate that opposing effects of bFGF and TGFβ1 on SMC gene expression control the phenotypic plasticity of SMCs.
Effects of Long-Term Daily Low-Dose Supplementation With Antioxidant Vitamins and Minerals on Structure and Function of Large Arteries
Authors: Zureik Mahmoud , Galan Pilar , Bertrais Sandrine , Mennen Louise , Czernichow Sébastien , Blacher Jacques , Ducimetière Pierre , Hercberg Serge
Published: June 2004

Objective—

Limited data exist from randomized trials evaluating, noninvasively, the impact of antioxidant supplementation on vascular structure and function.

Methods and Results—

This is a substudy of the SU.VI.MAX Study, which is a randomized, double-blind, placebo-controlled, cardiovascular and cancer primary prevention trial. Eligible participants (free of symptomatic chronic diseases and apparently healthy) were randomly allocated to daily receive either a combination of antioxidants (120 mg vitamin C, 30 mg vitamin E, 6 mg beta carotene, 100 μg selenium, and 20 mg zinc) or placebo and followed-up over an average of 7.2±0.3 years. At the end-trial examination, the carotid ultrasound examination and carotid–femoral pulse-wave velocity (PWV) measurement were performed blindly in 1162 subjects aged older than 50 years and living in the Paris area. The percentage of subjects with carotid plaques was higher in the intervention group compared with the placebo group (35.2% versus 29.5%,
P
=0.04). Common carotid intima-media thickness (mean±SD) was not different between the 2 groups (0.70±0.08 versus 0.70±0.08 mm,
P
=0.38). Mean PWV tended to be lower (indicating less stiff aortic arteries) in the intervention group but the difference did not reach statistical significance (
P
=0.13).

Conclusion—

These results suggest no beneficial effects of long-term daily low-dose supplementation of antioxidant vitamins and minerals on carotid atherosclerosis and arterial stiffness.
Genetic and Environmental Determinants of Fibrin Structure and Function
Authors: Scott Eleanor M. , Ariëns Robert A.S. , Grant Peter J.
Published: June 2004

The formation of a fibrin clot is one of the key events in atherothrombotic vascular disease. The structure of the fibrin clot and the genetic and environmental factors that modify it have effects on its biological function. Alterations in fibrin structure and function have implications for the clinical presentation of vascular disease. This review briefly describes the key features involved in the formation of a fibrin clot, its typical structure, and function. This is followed by a review of the current literature on genetic and environmental influences on fibrin structure/function and the relationship to clinical disease.
Asymmetric Dimethylarginine Produces Vascular Lesions in Endothelial Nitric Oxide Synthase–Deficient Mice
Authors: Suda Osamu , Tsutsui Masato , Morishita Tsuyoshi , Tasaki Hiromi , Ueno Susumu , Nakata Sei , Tsujimoto Takashi , Toyohira Yumiko , Hayashida Yoshiaki , Sasaguri Yasuyuki , Ueta Yoichi , Nakashima Yasuhide , Yanagihara Nobuyuki
Published: June 2004

Objective—

Asymmetric dimethylarginine (ADMA) is widely believed to be an endogenous nitric oxide synthase (eNOS) inhibitor. However, in this study, we examined our hypothesis that the long-term vascular effects of ADMA are not mediated by inhibition of endothelial NO synthesis.

Methods and Results—

ADMA was infused in wild-type and eNOS-knockout (KO) mice by osmotic minipump for 4 weeks. In wild-type mice, long-term treatment with ADMA caused significant coronary microvascular lesions. Importantly, in eNOS-KO mice, treatment with ADMA also caused an extent of coronary microvascular lesions that was comparable to that in wild-type mice. These vascular effects of ADMA were not prevented by supplementation of
l
-arginine, and vascular NO production was not reduced by ADMA treatment. Treatment with ADMA caused upregulation of angiotensin-converting enzyme (ACE) and an increase in superoxide production that were comparable in both strains and that were abolished by simultaneous treatment with temocapril (ACE inhibitor) or olmesartan (AT
1
receptor antagonist), which simultaneously suppressed vascular lesion formation.

Conclusions—

These results provide the first direct evidence that the long-term vascular effects of ADMA are not solely mediated by simple inhibition of endothelial NO synthesis. Direct upregulation of ACE and increased oxidative stress through AT
1
receptor appear to be involved in the long-term vascular effects of ADMA in vivo.
Valvular Myofibroblast Activation by Transforming Growth Factor-β
Authors: Walker Gennyne A. , Masters Kristyn S. , Shah Darshita N. , Anseth Kristi S. , Leinwand Leslie A.
Published: June 2004

The pathogenesis of cardiac valve disease correlates with the emergence of muscle-like fibroblasts (myofibroblasts). These cells display prominent stress fibers containing α-smooth muscle actin (α-SMA) and are believed to differentiate from valvular interstitial cells (VICs). However, the biological factors that initiate myofibroblast differentiation and activation in valves remain unidentified. We show that transforming growth factor-β1 (TGF-β1) mediates differentiation of VICs into active myofibroblasts in vitro in a dose-dependent manner, as determined by a significant increase in α-SMA and the dramatic augmentation of stress fiber formation and alignment. Additionally, TGF-β1 and increased mechanical stress function synergistically to enhance contractility. In turn, contractile valve myofibroblasts exert tension on the extracellular matrix, resulting in a dramatic realignment of extracellular fibronectin fibrils. TGF-β1 also inhibits valve myofibroblast proliferation without enhancing apoptosis. Our results are consistent with activation of a highly contractile myofibroblast phenotype by TGF-β1 and are the first to connect valve myofibroblast contractility with pathological valve matrix remodeling. We suggest that the activation of contractile myofibroblasts by TGF-β1 may be a significant first step in promoting alterations to the valve matrix architecture that are evident in valvular heart disease.
Differential and Opposing Regulation of PAI-1 Promoter Activity by Estrogen Receptor α and Estrogen Receptor β in Endothelial Cells
Authors: Smith Layton Harris , Coats Stephen R. , Qin Hao , Petrie Matthew S. , Covington Joseph W. , Su Ming , Eren Mesut , Vaughan Douglas E.
Published: June 2004

To investigate the molecular mechanisms involved in the estrogen-dependent control of plasminogen activator inhibitor-1 (PAI-1) gene expression in vascular cells, we compared the transactivation properties of estrogen receptors (ERα and ERβ) in regulating the activity of a human PAI-1 promoter reporter construct in transfected bovine aortic endothelial cells (BAECs). ERα increased PAI-1 promoter activity in BAECs by an estrogen-dependent mechanism, whereas ERβ suppressed PAI-1 promoter activity by an estrogen-independent mechanism. The suppressive activity of ERβ was dominant over the inductive activity of ERα. Mutation of a putative estrogen response element (ERE) located at position −427 in the proximal promoter abolished the ERα action without influencing the suppressive effects of ERβ. Mutation of either AP1-like site did not eliminate the ERα or ERβ actions at the PAI-1 promoter, suggesting that other promoter elements are involved in these responses. These mutations significantly reduced the −3.4kbp PAI-1 promoter response to serum. We concluded that ERα and ERβ exert differential effects on the PAI-1 promoter activity in transfected BAECs. ERα activated the PAI-1 promoter through a proximal ERE (−427) and possibly additional EREs located within the PAI-1 promoter, whereas ERβ suppressed the promoter construct via an unidentified mechanism. This is the first demonstration of the differential regulation of a vascular gene promoter by ERα and ERβ.
Partial Inhibition of Sodium/Calcium Exchange Restores Cellular Calcium Handling in Canine Heart Failure
Authors: Hobai Ion A. , Maack Christoph , O’Rourke Brian
Published: June 2004

Sodium/calcium (Na
+
/Ca
2+
) exchange (NCX) overexpression is common to human heart failure and heart failure in many animal models, but its specific contribution to the cellular Ca
2+
([Ca
2+
]
i
) handling deficit is unclear. Here, we investigate the effects of exchange inhibitory peptide (XIP) on Ca
2+
handling in myocytes isolated from canine tachycardic pacing-induced failing hearts. Whole-cell patch-clamped left ventricular myocytes from failing hearts (F) showed a 52% decrease in steady-state sarcoplasmic reticulum (SR) Ca
2+
load and a 44% reduction in the amplitude of the [Ca
2+
]
i
transient, as compared with myocytes from normal hearts (N). Intracellular application of XIP (30 μmol/L) normalized the [Ca
2+
]
i
transient amplitude in F (3.86-fold increase), concomitant with a similar increase in SR Ca
2+
load. The degree of NCX inhibition at this concentration of XIP was ≈27% and was selective for NCX: L-type Ca
2+
currents and plasmalemmal Ca
2+
pumps were not affected. XIP also indirectly improved the rate of [Ca
2+
]
i
removal at steady-state, secondary to Ca
2+
-dependent activation of SR Ca
2+
uptake. The findings indicate that in the failing heart cell, NCX inhibition can improve SR Ca
2+
load by shifting the balance of Ca
2+
fluxes away from trans-sarcolemmal efflux toward SR accumulation. Hence, inhibition of the Ca
2+
efflux mode of the exchanger could potentially be an effective therapeutic strategy for improving contractility in congestive heart failure.
Stroke Risk Profile Predicts White Matter Hyperintensity Volume
Authors: Jeerakathil Tom , Wolf Philip A. , Beiser Alexa , Massaro Joseph , Seshadri Sudha , D’Agostino Ralph B. , DeCarli Charles
Published: June 2004

Background and Purpose—

Previous studies of cardiovascular risk factors and white matter hyperintensity (WMH) on brain MRI have been limited by the failure to exclude symptomatic cerebrovascular disease and dementia or by the use of semiquantitative rather than quantitative methods to measure WMH volume (WMHV). We examined the relationship between Framingham Stroke Risk Profile (FSRP) and WMHV measured quantitatively in a stroke and dementia-free subset of the Framingham Offspring Cohort.

Methods—

Brain MRI was performed in 1814 members of the Framingham Offspring Cohort. Pixel-based quantitative measures of WMHV corrected for head size were obtained using a semiautomated algorithm. WMHV was not normally distributed and therefore was log-transformed (LWMHV). The FSRP and its component risk factors measured a mean of 7.5 years before MRI were related to both continuous measures of LWMHV and to the presence of large volumes of LWMHV (LWMHV-large). All analyses were adjusted for age and sex.

Results—

FSRP was strongly associated with LWMHV and LWMHV-large. Age, smoking, history of cardiovascular disease, hypertension, and left ventricular hypertrophy by electrocardiogram were all significantly related to LWMHV or LWMHV-large.

Conclusions—

FSRP and several cardiovascular risk factors were related to both WMHV measured continuously and to a categorical designation of large volumes of WMH. These findings provide strong evidence of a vascular basis for WMH.
Impact of Premorbid Undernutrition on Outcome in Stroke Patients
Authors: Davis James P. , Wong Andrew A. , Schluter Philip J. , Henderson Robert D. , O’Sullivan John D. , Read Stephen J.
Published: June 2004

Background and Purpose—

To assess the prevalence of premorbid undernutrition and its impact on outcomes 1 month after stroke.

Methods—

The study recruited from consecutive stroke admissions during a 10-month period. Premorbid nutritional status (using the subjective global assessment [SGA]), premorbid functioning (modified Rankin scale [MRS]), and stroke severity (National Institutes of Health Stroke Scale [NIHSS] score) were assessed at admission. The associations between premorbid nutritional status, poor outcome (defined as MRS ≥3), and mortality were examined before and after adjustment for confounding variables, including age, gender, stroke risk factors, stroke severity, and admission serum albumin.

Results—

Thirty of 185 patients were assessed as having undernutrition at admission. Significant unadjusted associations were observed between undernutrition and poor outcome (odds ratio [OR], 3.4; 95% CI, 1.3 to 8.7;
P
=0.01), and mortality (OR, 3.1, 95% CI, 1.3 to 7.7;
P
=0.02) at 1 month. NIHSS, age, and premorbid MRS were also significantly associated with poor outcomes. After adjustment for these factors, the effect size of associations remained important but not significant (poor outcome: OR, 2.4; 95% CI, 0.7 to 9.0,
P
=0.18; mortality: OR, 3.2; 95% CI, 1.0 to 10.4,
P
=0.05).

Conclusions—

Premorbid undernutrition, as assessed using the SGA, appears to be an independent predictor of poor stroke outcome. Stroke prevention strategies should target undernutrition in the population at risk for stroke to improve outcomes.
Breeding behavior of the leaf-frog Phyllomedusa burmeisteri (Anura: Hylidae)
Authors: Abrunhosa Patrícia , Wogel Henrique
Published: June 2004

Phyllomedusa burmeisteri was studied during breeding aggregations in a temporary pond in southeastern Brazil. Males were territorial and aggressive. Behavioral patterns exhibited by them included acoustical and visual communication, chase, and wrestling, the latter when the intruder did not retreat with the preceding threats. Females also performed visual displays, however in different contexts, before approaching toward a calling male. The vocal repertoire of P. burmeisteri consisted of two types of advertisement call (short type and long type), territorial call and encounter call. Information about spatial-temporal distribution, courtship, and mating behavior are presented.
Envenomated-invertebrate prey preference of the viperid Agkistrodon contortrix during strike-induced chemosensory searching
Authors: Greenbaum Eli , Jorgensen Michael
Published: June 2004

Many crotaline snakes exhibit envenomated-prey preference in laboratory experiments. We examined the ability of copperheads (Agkistrodon contortrix) to distinguish between envenomated and nonenvenomated tobacco hornworm larvae (Manduca sexta). Snakes directed significantly more tongue flicks at envenomated hornworms than at nonenvenomated hornworms, and snakes consumed envenomated hornworms more frequently than nonenvenomated prey. These results support the hypothesis that envenomated tissue is an important stimulus to copperheads during strike-induced chemosensory searching. Copperheads preferred hornworms envenomated by conspecifics in the relative order: Louisiana > Texas > Kansas; this preference matches the relative order of preference and venom potency documented in a previous study of copperheads for envenomated mice. We conclude that the venom protein-prey tissue interaction responsible for the observed behaviour is similar in both invertebrate and rodent prey items.
Targeting mitochondria to overcome conventional and bortezomib/proteasome inhibitor PS-341 resistance in multiple myeloma (MM) cells
Authors: Chauhan Dharminder , Li Guilan , Podar Klaus , Hideshima Teru , Mitsiades Constantine , Schlossman Robert , Munshi Nikhil , Richardson Paul , Cotter Finbarr E. , Anderson Kenneth C.
Published: June 2004

Bortezomib (PS-341), a selective inhibitor of proteasomes, induces apoptosis in multiple myeloma (MM) cells; however, prolonged drug exposure may result in cumulative toxicity and the development of chemoresistance. Here we show that combining PK-11195 (PK), an antagonist to mitochondrial peripheral benzodiazepine receptors (PBRs), with bortezomib triggers synergistic anti-MM activity even in doxorubicin-, melphalan-, thalidomide-, dexamethasone-, and bortezomib-resistant MM cells. No significant cytotoxicity was noted in normal lymphocytes. Low-dose combined PK and bortezomib treatment overcomes the growth, survival, and drug resistance conferred by interleukin-6 or insulin growth factor within the MM bone marrow milieu. The mechanism of PK + bortezomib–induced apoptosis includes: loss of mitochondrial membrane potential; superoxide generation; release of mitochondrial proteins cytochrome-c (cyto-c) and Smac; and activation of caspases-8/-9/-3. Furthermore, PK + bortezomib activates c-Jun NH2 terminal kinase (JNK), which translocates to mitochondria, thereby facilitating release of cyto-c and Smac from mitochondria to cytosol. Blocking JNK, by either dominant-negative mutant (DN-JNK) or cotreatment with a specific JNK inhibitor SP600125, abrogates both PK + bortezomib–induced release of cyto-c/Smac and induction of apoptosis. Together, these preclinical studies suggest that combining bortezomib with PK may enhance its clinical efficacy, reduce attendant toxicity, and overcome conventional and bortezomib resistance in patients with relapsed refractory MM.
Kit and FcϵRI mediate unique and convergent signals for release of inflammatory mediators from human mast cells
Authors: Hundley Thomas R. , Gilfillan Alasdair M. , Tkaczyk Christine , Andrade Marcus V. , Metcalfe Dean D. , Beaven Michael A.
Published: June 2004

In human mast cells, derived from CD34+ peripheral blood cells, we observed that Kit ligand (KL) failed to induce degranulation but acted in synergy with antigen to markedly enhance degranulation, levels of cytokine gene transcripts, and production of cytokines. Further examination revealed that antigen and KL activated common and unique signaling pathways to account for these varied responses. KL, unlike antigen, failed to activate protein kinase C but activated phospholipase Cγ and calcium mobilization and augmented these signals as well as degranulation when added together with antigen. Both KL and antigen induced signals that are associated with cytokine production, namely phosphorylation of the mitogen-activated protein kinases, phosphatidylinositol 3–kinase–dependent phosphorylation of protein kinase B (also known as Akt), and phosphorylation of nuclear factor κB (NFκB). However, only KL stimulated phosphorylation of signal transducer and activator of transcription 5 (STAT5) and STAT6, whereas antigen weakly stimulated the protein kinase C–dependent induction and phosphorylation of c-Jun and associated activating protein-1 (AP-1) components, an action that was markedly potentiated by costimulation with KL. Interestingly, most signals were down-regulated on continuous exposure to KL but were reactivated along with cytokine gene transcription on addition of antigen. The findings, in total, indicated that a combination of FcϵRI and Kit-mediated signals and transcriptional processes were required for optimal physiologic responses of human mast cells to antigen.
FCGR3A and FCGR2A polymorphisms may not correlate with response to alemtuzumab in chronic lymphocytic leukemia
Authors: Lin Thomas S. , Flinn Ian W. , Modali Rama , Lehman Teresa A. , Webb Jennifer , Waymer Sharon , Moran Mollie E. , Lucas Margaret S. , Farag Sherif S. , Byrd John C.
Published: June 2004

The in vivo mechanism of action of alemtuzumab (anti-CD52; Campath-1H) remains unclear. With rituximab, FCGR3A and FCGR2A high-affinity polymorphisms have been associated with clinical response in lymphoma but not in CLL, suggesting potential divergent mechanisms of action between these 2 diseases. Herein, we examined FCGR3A (V/V, n = 4; V/F, n = 10; F/F, n = 19) and FCGR2A (A/A, n = 5; H/A, n = 22; H/H, n = 6) polymorphisms in 36 patients with relapsed CLL who were treated with thrice-weekly alemtuzumab for 12 weeks to assess the potential influence these high-affinity FcγR receptor polymorphisms had on response to alemtuzumab. Response to alemtuzumab was similar regardless of FCGR3A polymorphism (V/V, 25%; V/F, 40%; F/F, 32%) or FCGR2A polymorphism (A/A, 40%; H/A, 32%; H/H, 33%). These findings indicate that FCGR3A and FCGR2A polymorphisms may not predict response to alemtuzumab in CLL. Future studies examining larger cohorts of alemtuzumab-treated patients with CLL will be required to definitively determine the predictive value of specific FCGR polymorphisms to treatment response. (Blood. 2005;105:289-291)
Chronic lymphocytic leukemia B cells of more than 1% of patients express virtually identical immunoglobulins
Authors: Widhopf George F. , Rassenti Laura Z. , Toy Traci L. , Gribben John G. , Wierda William G. , Kipps Thomas J.
Published: June 2004

We examined the immunoglobulin (Ig) heavy chain variable region genes (VH genes) used by leukemia cells of 1220 unrelated patients with chronic lymphocytic leukemia (CLL). We found 1188 (97%) expressed Ig encoded by a single Ig VH subgroup, the most common of which was VH3 (571 or 48.1%), followed by VH1 (319 or 26.8%) and VH4 (241 or 20.2%). Using allele-specific primers, we found 13.8% of all samples (n = 164) used one major VH1-69 allele, designated 51p1, 163 of which were not somatically mutated. For these cases, there was marked restriction in the structure of the Ig third complementarity determining regions (CDR3s), which were encoded by a small number of unmutated D and JH gene segments. Strikingly, 15 of the 163 cases had virtually identical CDR3s encoded by the second reading frame of D3-16 and JH3. Further analysis revealed that each of these 15 samples used the same unmutated Ig kappa light-chain gene, namely A27. These data reveal that approximately 1.3% (15/1220) of all patients had leukemia cells that expressed virtually identical Ig. This finding provides compelling evidence that the Ig expressed by CLL B cells are highly selected and not representative of the Ig expressed by naive B cells.
PTX-sensitive signals in bone marrow homing of fetal and adult hematopoietic progenitor cells
Authors: Bonig Halvard , Priestley Gregory V. , Nilsson Lina M. , Jiang Yi , Papayannopoulou Thalia
Published: June 2004

Several examples suggest a relationship between in vitro migratory capacity and bone marrow (BM) homing. Pertussis toxin (PTX) is a potent inhibitor of serpentine receptor–associated inhibitory trimeric guanidine nucleotide binding (Gi) protein signals. As such, it blocks hematopoietic progenitor cell migration in vitro, but contrary to expectation, no effects on BM homing were observed in previous studies. We therefore re-examined the effect of PTX on homing of murine BM and fetal liver (FL). We found that BM homing of PTX-incubated progenitor cells (colony-forming cells in culture [CFU-Cs]) from BM or FL in irradiated and nonirradiated recipients was reduced by more than 75%, with a concomitant increase in circulating CFU-Cs in peripheral blood. Additional studies confirmed the functional significance of this reduction in homing: PTX-treated cells did not provide radioprotection, and their short-term engraftment in BM and spleen was drastically reduced. Furthermore, several approaches show that cell-intrinsic rather than host-derived mechanisms are responsible for the PTX-induced homing defect. In summary, we show that Gi protein signals are required for BM homing and, as such, provide a new example of the association between BM homing and in vitro migration. Moreover, our data suggest that the behavior of hematopoietic progenitors in obeying Gi signaling does not diverge from that of mature leukocytes.
Diazepam-binding inhibitor-related protein 1: a candidate autoantigen in acquired aplastic anemia patients harboring a minor population of paroxysmal nocturnal hemoglobinuria–type cells
Authors: Feng Xingmin , Chuhjo Tatsuya , Sugimori Chiharu , Kotani Takeharu , Lu Xuzhang , Takami Akiyoshi , Takamatsu Hiroyuki , Yamazaki Hirohito , Nakao Shinji
Published: June 2004

To identify candidate antigens in aplastic anemia (AA), we screened proteins derived from a leukemia cell line with serum of an AA patient and identified diazepam-binding inhibitor-related protein 1 (DRS-1). Enzyme-linked immunosorbent assay (ELISA) revealed high titers of anti–DRS-1 antibodies (DRS-1 Abs) in 27 (38.0%) of 71 AA patients displaying increased paroxysmal nocturnal hemoglobinuria (PNH)–type cells (PNH+), 2 (6.3%) of 32 PNH– AA patients, 5 (38.5%) of 13 PNH+ myelodysplastic syndrome (MDS) patients, and none of 42 PNH– MDS patients. DRS-1 gene was abundantly expressed in myeloid leukemia cell lines and in CD34+ cells derived from healthy individuals. Stimulation of T cells from an AA patient displaying high DRS-1 Abs with a putative CD4+ T-cell epitope (amino acid residues [aa's] 191-204) presented by HLA-DR15, which overlapped with a hot spot (aa's 173-198) of DRS-1 Ab epitopes, gave rise to T cells cytotoxic for L cells (murine fibroblasts) that were transfected with DRB1*1501 and DRS-1. Enzyme-linked immunospot assay demonstrated increased frequency of T-cell precursors specific to the DRS-1 peptide in other HLA-DR15+ AA patients displaying high DRS-1 Ab titers. These findings indicate that DRS-1 may serve as an autoantigen eliciting immune attack against hematopoietic stem cells in a subset of AA patients characterized by increased PNH-type cells.