bluuebunny/crossref_metadata_2025 huggingface dataset:
Candidate mechanical stimuli for hypertrophy during volume overload
Authors: Holmes Jeffrey W.
Published: June 2004

A myocyte system that senses and responds to mechanical inputs might be activated by any number of features of the time-varying length or force signals experienced by the myocytes. We therefore characterized left ventricular volume and wall stress signals during early volume overload with high spatial and temporal resolution. Left ventricular pressure and volume were measured in open-chest isoflurane-anesthetized male Sprague-Dawley rats 4 and 7 days after surgical creation of an infrarenal arteriovenous fistula or sham operation. Mean wall stresses were calculated by using a simple thick-walled ellipsoidal model. Consistent with previous reports, this surgical model produced a 66% increase in cardiac output and a 10% increase in left ventricular mass by day 7. A number of features of the time-varying volume signal (maximum, mean, amplitude, rates of rise and fall) were significantly altered during early volume overload, whereas many other proposed hypertrophic stimuli, including peak systolic wall stress and diastolic strain, were not. Treating hemodynamic variables more generally as time-varying signals allowed us to identify a wider range of candidate mechanical stimuli for hypertrophy (including some not previously proposed in the literature) than focusing on standard time points in the cardiac cycle. We conclude that features of the time-varying ventricular volume signal and related local deformations may drive hypertrophy during volume overload and propose that those features of the volume signal that also change during pressure overload might be the most interesting candidates for further exploration.
Sex-specific changes in platelet aggregation and secretion with sexual maturity in pigs
Authors: Jayachandran Muthuvel , Okano Hiroya , Chatrath Ritu , Owen Whyte G. , McConnell Joseph P. , Miller Virginia M.
Published: June 2004

Cardiovascular disease may begin early in adolescence. Platelets release factors contributing to vascular disease. Experiments were designed to test the hypothesis that hormonal transitions associated with sexual maturity differentially affect platelet aggregation and secretion in males and females. Platelets were collected from juvenile (2–3 mo) and sexually mature (adult; 5–6 mo) male and female pigs ( n = 8/group). Maturation was evidenced by increased weight of reproductive tissue and changes in circulating levels of gonadal hormones. Aggregation to ADP (10 μM) and collagen (6 μg/ml) and ATP secretion to 50 nM thrombin were determined by turbidimetric analysis and bioluminescence, respectively. Total platelet counts, platelet turnover, and mean platelet volume did not change with maturity. Platelet aggregation and ATP secretion decreased in females but increased in males with maturity, whereas total ATP content remained unchanged in platelets from females but increased in platelets from males. Platelet fibrinogen receptor, P-selectin expression, and receptors for sex steroids did not change with sexual maturation. Plasma C-reactive protein and brain-type natriuretic peptide also did not change. Results indicate that changes in platelet aggregation and secretion change with sexual maturity differently in females and males. These observations provide evidence on which clinical studies could be designed to examine platelet characteristics in human children and young adults.
Severity of sepsis alters the effects of superoxide anion inhibition in a rat sepsis model
Authors: Cui Xizhong , Parent Chantal , Macarthur Heather , Ochs Scott D. , Gerstenberg Eric , Solomon Steve , Fitz Yvonne , Danner Robert L. , Banks Steven M. , Natanson Charles , Salvemini Daniela , Eichacker Peter Q.
Published: May 2004

Previous analysis showed that selective inhibitors of five different host inflammatory mediators administered for sepsis, although beneficial with severe sepsis and high-control mortality rates, were ineffective or harmful with less severe sepsis. We hypothesized that severity of sepsis would also influence inhibition of superoxide anion, another inflammatory mediator. To test this, 6-h infusions of M40401, a selective SOD mimetic, or placebo were given to antibiotic-treated rats ( n = 547) starting 3 h after challenge with differing doses of intravenous Escherichia coli designed to produce low- or high-control mortality rates. There was a positive and significant ( P = 0.0008) relationship between the efficacy of M40401 on survival rate and control mortality rates. M40401 increased or decreased the log (odds ratio of survival) (means ± SE), dependent on whether control mortality rates were greater or less than the median (66%) (+0.19 ± 0.12 vs. −0.25 ± 0.10, P = 0.01). In a subset of animals examined ( n = 152) at 9 h after E. coli challenge, M40401 increased (mean effect ± SE compared with control) mean arterial blood pressure (8 ± 5 mmHg) and decreased platelets (−37 ± 22 cells × 103/ml) with high-control mortality rates but had opposing effects on each parameter (−3 ± 3 mmHg and 28 ± 19 cells × 103/ml, respectively) with low rates ( P ≤ 0.05 for the differing effects of M40401 on each parameter with high- vs. low-control mortality rates). A metaregression analysis of published preclinical sepsis studies testing SOD preparations and SOD mimetics showed that most (16 of 18) had control mortality rates >66%. However, across experiments from published studies, these agents were less beneficial as control mortality rate decreased ( P = 0.03) in a relationship not altered ( P = not significant) by other variables associated with septic challenge or regimen of treatment and which was similar, compared with experiments with M40401 ( P = not significant). Thus, in these preclinical sepsis models, possibly related to divergent effects on vascular function, inhibition of superoxide anion improved survival with more severe sepsis and high-control mortality rates but was less effective or harmful with less severe sepsis. Extrapolated clinically, inhibition of superoxide anion may be most efficacious in septic patients with severe sepsis and a high risk of death.
Noninvasive determination of upper airway resistance and flow limitation
Authors: Mansour Khaled F. , Rowley James A. , Badr M. Safwan
Published: May 2004

We have shown that a polynomial equation, F(P) = AP3 + BP2 + CP + D, where F is flow and P is pressure, can accurately determine the presence of inspiratory flow limitation (IFL). This equation requires the invasive measurement of supraglottic pressure. We hypothesized that a modification of the equation that substitutes time for pressure would be accurate for the detection of IFL and allow for the noninvasive measurement of upper airway resistance. The modified equation is F( t) = At3 + Bt2 + Ct + D, where F is flow and t is time from the onset of inspiration. To test our hypotheses, data analysis was performed as follows on 440 randomly chosen breaths from 18 subjects. First, we performed linear regression and determined that there is a linear relationship between pressure and time in the upper airway ( R2 0.96 ± 0.05, slope 0.96 ± 0.06), indicating that time can be a surrogate for pressure. Second, we performed curve fitting and found that polynomial equation accurately predicts the relationship between flow and time in the upper airway ( R2 0.93 ± 0.12, error fit 0.02 ± 0.08). Third, we performed a sensitivity-specificity analysis comparing the mathematical determination of IFL to manual determination using a pressure-flow loop. Mathematical determination had both high sensitivity (96%) and specificity (99%). Fourth, we calculated the upper airway resistance using the polynomial equation and compared the measurement to the manually determined upper airway resistance (also from a pressure-flow loop) using Bland-Altman analysis. Mean difference between calculated and measured upper airway resistance was 0.0 cmH2O·l−1·s−1 (95% confidence interval −0.2, 0.2) with upper and lower limits of agreement of 2.8 cmH2O·l−1·s−1 and −2.8 cmH2O·l−1·s−1. We conclude that a polynomial equation can be used to model the flow-time relationship, allowing for the objective and accurate determination of upper airway resistance and the presence of IFL.
Sympathetic Influence on Capsaicin-Evoked Enhancement of Dorsal Root Reflexes in Rats
Authors: Wang Jing , Ren Yong , Zou Xiaoju , Fang Li , Willis William D. , Lin Qing
Published: May 2004

A series of experiments by our group suggest that the initiation and development of neurogenic inflammation in rats are mainly mediated by dorsal root reflexes (DRRs), which are conducted centrifugally from the spinal dorsal horn in primary afferent nocieptors. In this study, DRRs were recorded in anesthetized rats from single afferent fibers in the proximal ends of cut dorsal root filaments at the L4–L6 level and tested for responses to intradermal injection of capsaicin. Sympathectomy combined with pharmacological manipulations were employed to determine if the capsaicin-evoked enhancement of DRRs was subject to sympathetic modulation. DRRs could be recorded from both myelinated (Aβ and Aδ) and unmyelinated (C) afferent fibers. After capsaicin was injected intradermally into the plantar foot, a significant enhancement of DRRs was seen in C- and Aδ-fibers but not in Aβ-fibers. This enhancement of DRRs evoked by capsaicin injection was almost completely prevented by sympathectomy. However, if peripheral α1-adrenoceptors were activated by intra-arterial injection of phenylephrine, the enhancement of DRRs evoked by capsaicin could be restored, whereas no such restoration was seen following pretreatment with an α2-adrenoceptor agonist, UK14,304. Under sympathetically intact conditions, the enhanced DRRs following capsaicin injection could be blocked by administration of terazosin, an α1-adrenoceptor antagonist, but not by administration of yohimbine, an α2-adrenoceptor antagonist. These results provide further evidence that the DRR-mediated neurogenic inflammation depends in part on intact sympathetic efferents acting on peripheral α1-adrenoceptors, which augment the sensitization of primary afferent nociceptors induced by capsaicin injection, helping trigger DRRs that produce vasodilation.
Functional Properties of Grasping-Related Neurons in the Dorsal Premotor Area F2 of the Macaque Monkey
Authors: Raos Vassilis , Umiltá Maria-Alessandra , Gallese Vittorio , Fogassi Leonardo
Published: May 2004

We investigated the properties of neurons located in the distal forelimb field of dorsal premotor area F2 of macaque monkey using a behavioral paradigm for studying the neuronal discharge during observation (object fixation condition) and grasping of different 3-dimensional objects with and without visual guidance of the movement (movement in light and movement in dark conditions, respectively). The main result is that almost all studied neurons were selective for both the type of prehension and the wrist orientation required for grasping an object. Three categories of neurons were found: purely motor, visually modulated, and visuomotor neurons. The discharge of purely motor neurons was not affected by either object presentation or by the visual feedback of the hand approaching to and interacting with the object. Visually modulated neurons presented a different discharge in the 2 movement conditions, this determining a decrease in selectivity for the grip and wrist orientation in the movement in dark condition. Visuomotor neurons typically discharged during the object fixation task even in the absence of any grasping movement. Nine of them also displayed a different discharge rate between the 2 movement conditions. Congruence was observed between the neuron response during the most effective type of prehension and the neuron response during observation of the object requiring that particular prehension. These results indicate an important role of F2 in the control of goal-related hand movements.
A Possible Role of Midbrain Dopamine Neurons in Short- and Long-Term Adaptation of Saccades to Position-Reward Mapping
Authors: Takikawa Yoriko , Kawagoe Reiko , Hikosaka Okihide
Published: May 2004

Dopamine (DA) neurons respond to sensory stimuli that predict reward. To understand how DA neurons acquire such ability, we trained monkeys on a one-direction-rewarded version of memory-guided saccade task (1DR) only when we recorded from single DA neurons. In 1DR, position-reward mapping was changed across blocks of trials. In the early stage of training of 1DR, DA neurons responded to reward delivery; in the later stages, they responded predominantly to the visual cue that predicted reward or no reward (reward predictor) differentially. We found that such a shift of activity from reward to reward predictor also occurred within a block of trials after position-reward mapping was altered. A main effect of long-term training was to accelerate the within-block reward-to-predictor shift of DA neuronal responses. The within-block shift appeared first in the intermediate stage, but was slow, and DA neurons often responded to the cue that indicated reward in the preceding block. In the advanced stage, the reward-to-predictor shift occurred quickly such that the DA neurons' responses to visual cues faithfully matched the current position-reward mapping. Changes in the DA neuronal responses co-varied with the reward-predictive differentiation of saccade latency both in short-term (within-block) and long-term adaptation. DA neurons' response to the fixation point also underwent long-term changes until it occurred predominantly in the first trial within a block. This might trigger a switch between the learned sets. These results suggest that midbrain DA neurons play an essential role in adapting oculomotor behavior to frequent switches in position-reward mapping.
Response Properties of Whisker-Related Neurons in Rat Second Somatosensory Cortex
Authors: Kwegyir-Afful Ernest E. , Keller Asaf
Published: May 2004

In addition to a primary somatosensory cortex (SI), the cerebral cortex of all mammals contains a second somatosensory area (SII); however, the functions of SII are largely unknown. Our aim was to explore the functions of SII by comparing response properties of whisker-related neurons in this area with their counterparts in the SI. We obtained extracellular unit recordings from narcotized rats, in response to whisker deflections evoked by a piezoelectric device, and compared response properties of SI barrel (layer IV) neurons with those of SII (layers II to VI) neurons. Neurons in both cortical areas have similar response latencies and spontaneous activity levels. However, SI and SII neurons differ in several significant properties. The receptive fields of SII neurons are at least five times as large as those of barrel neurons, and they respond equally strongly to several principal whiskers. The response magnitude of SII neurons is significantly smaller than that of neurons in SI, and SII neurons are more selective for the angle of whisker deflection. Furthermore, whereas in SI fast-spiking (inhibitory) and regular-spiking (excitatory) units have different spontaneous and evoked activity levels and differ in their responses to stimulus onset and offset, SII neurons do not show significant differences in these properties. The response properties of SII neurons suggest that they are driven by thalamic inputs that are part of the paralemniscal system. Thus whisker-related inputs are processed in parallel by a lemniscal system involving SI and a paralemniscal system that processes complimentary aspects of somatosensation.
A-Current Expression is Regulated by Activity but not by Target Tissues in Developing Lumbar Motoneurons of the Chick Embryo
Authors: Casavant Reema H. , Colbert Costa M. , Dryer Stuart E.
Published: June 2004

The functional expression of A-type K+ channels ( IA) was examined in chick lumbar motoneurons (LMNs) at embryonic days 6 and 11 (E6 and E11). We observed a threefold increase in IA density between E6 and E11 in spinal cord slices and acutely dissociated LMNs. There was no change in current density, kinetics, or voltage dependence of IA in E11 homozygous limbless mutants or in E11 embryos in which hindlimbs were surgically removed at E6. Moreover, chronic in ovo administration of d-tubocurarine, which causes an increase in motoneuron branching on the surface of target muscles, had no effect on IA. Electrical activity played an important role in IA regulation in LMNs in vitro and in ovo. Blocking spontaneous electrical activity of LMNs by chronic in ovo application of mecamylamine or muscimol reduced IA by 80%. LMNs cultured in the presence of TTX also failed to express normal densities of IA, even when the cultures also contained target tissues. The portion of IA that remained after in ovo or in vitro blockade of activity inactivated more quickly than the IA of LMNs that were allowed to discharge spikes. The developmental expression of LMN IA increases significantly during development, and this increase is activity dependent but does not require interactions with target tissues. Ongoing activity also seems to regulate the kinetics of IA inactivation.
Auditory Saccades From Different Eye Positions in the Monkey: Implications for Coordinate Transformations
Authors: Metzger Ryan R. , Mullette-Gillman O'Dhaniel A. , Underhill Abigail M. , Cohen Yale E. , Groh Jennifer M.
Published: June 2004

Auditory spatial information arises in a head-centered coordinate frame, whereas the saccade command signals generated by the superior colliculus (SC) are thought to specify target locations in an eye-centered frame. However, auditory activity in the SC appears to be neither head- nor eye-centered but in a reference frame that is intermediate between both of these reference frames. This neurophysiological finding suggests that auditory saccades might not fully compensate for changes in initial eye position. Here, we investigated whether the accuracy of saccades to sounds is affected by initial eye position in rhesus monkeys. We found that, on average, a 12° horizontal shift in initial eye position produced only a 0.6 to 1.6° horizontal shift in the endpoints of auditory saccades made to targets at a range of locations along the horizontal meridian. This shift was similar in size to the modest influence of eye position on visual saccades. This virtually complete compensation for initial eye position implies that auditory activity in the SC is read out in a manner that is appropriate for generating accurate saccades to sounds.
Lamina I, but not Lamina V, Spinothalamic Neurons Exhibit Responses That Correspond With Burning Pain
Authors: Craig A. D.
Published: June 2004

Single-unit recordings from monkey spinothalamic tract (STT) neurons reveal that the responses of polymodal nociceptive lamina I STT neurons correspond with the profile of burning pain elicited in human subjects by repeated brief-contact heat. In contrast, lamina V wide-dynamic-range (WDR) neurons show a significantly different response pattern. This finding indicates that burning pain is signaled by modality-selective lamina I neurons and not convergent lamina V WDR neurons.
Contribution ofIhand GABABto Synaptically Induced Afterhyperpolarizations in CA1: A Brake on the NMDA Response
Authors: Otmakhova Nonna A. , Lisman John E.
Published: June 2004

CA1 pyramidal cells receive two major excitatory inputs: the perforant path (PP) terminates in the most distal dendrites, whereas the Schaffer collaterals (SC) terminate more proximally. We have examined the mechanism of the afterhyperpolarization (AHP) that follows single subthreshold excitatory postsynaptic potentials (EPSPs) in these inputs. The AHPs were not reduced by a GABAAantagonist or by agents that block Ca2+entry. Application of the Ihblocker, ZD7288, partially blocked the AHP in the PP; the substantial remaining component was blocked by 2-hydroxysaclofen, a GABABantagonist. In contrast, the AHP in the SC depends nearly completely on Ih, with almost no GABABcomponent. Thus postsynaptic GABABreceptors appear to be preferentially involved at distal synapses, consistent with the spatial distribution of GABABreceptors and g protein-coupled inward rectifying potassium (GIRK) channels. GABABdoes, however, play a role at proximal synapses through presynaptic suppression of glutamate release, a mechanism that is much weaker at distal synapses. Experiments were conducted to explore the functional role of the AHP in the PP, which has a higher N-methyl-d-aspartate (NMDA)/AMPA ratio than the SC. Blockade of the AHP converted a response that had a small NMDA component to one that had a large component. These results indicate that the Ihand postsynaptic GABABconductances act as a brake on distally generated NMDA responses.
Properties of Primary Motor Cortex Output to Forelimb Muscles in Rhesus Macaques
Authors: Park Michael C. , Belhaj-Saïf Abderraouf , Cheney Paul D.
Published: May 2004

Stimulus-triggered averaging (StTA) of electromyographic (EMG) activity from 24 simultaneously recorded forelimb muscles was used to investigate properties of primary motor cortex (M1) output in the macaque monkey. Two monkeys were trained to perform a reach-to-grasp task requiring multijoint coordination of the forelimb. EMG activity was recorded from 24 forelimb muscles including 5 shoulder, 7 elbow, 5 wrist, 5 digit, and 2 intrinsic hand muscles. Microstimulation (15 μA at 15 Hz) was delivered throughout the movement task. From 297 stimulation sites in M1, a total of 2,079 poststimulus effects (PStE) were obtained including 1,398 poststimulus facilitation (PStF) effects and 681 poststimulus suppression (PStS) effects. Of the PStF effects, 60% were in distal and 40% in proximal muscles; 43% were of extensors and 47% flexors. For PStS, the corresponding numbers were 55 and 45% and 36 and 55%, respectively. M1 output effects showed extensive cofacilitation of proximal and distal muscles (96 sites, 42%) including 47 sites that facilitated at least one shoulder, elbow, and distal muscle, 45 sites that facilitated an elbow muscle and a distal muscle, and 22 sites that facilitated at least one muscle at all joints. The muscle synergies represented by outputs from these sites may serve an important role in the production of coordinated, multijoint movements. M1 output effects showed many similarities with red nucleus output although red nucleus effects were generally weaker and showed a strong bias toward facilitation of extensor muscles and a greater tendency to facilitate synergies involving muscles at noncontiguous joints.
Patterns of Muscle Activity Underlying Object-Specific Grasp by the Macaque Monkey
Authors: Brochier T. , Spinks R. L. , Umilta M. A. , Lemon R. N.
Published: June 2004

During object grasp, a coordinated activation of distal muscles is required to shape the hand in relation to the physical properties of the object. Despite the fundamental importance of the grasping action, little is known of the muscular activation patterns that allow objects of different sizes and shapes to be grasped. In a study of two adult macaque monkeys, we investigated whether we could distinguish between EMG activation patterns associated with grasp of 12 differently shaped objects, chosen to evoke a wide range of grasping postures. Each object was mounted on a horizontal shuttle held by a weak spring (load force 1–2 N). Objects were located in separate sectors of a “carousel,” and inter-trial rotation of the carousel allowed sequential presentation of the objects in pseudorandom order. EMG activity from 10 to 12 digit, hand, and arm muscles was recorded using chronically implanted electrodes. We show that the grasp of different objects was characterized by complex but distinctive patterns of EMG activation. Cluster analysis shows that these object-related EMG patterns were specific and consistent enough to identify the object unequivocally from the EMG recordings alone. EMG-based object identification required a minimum of six EMGs from simultaneously recorded muscles. EMG patterns were consistent across recording sessions in a given monkey but showed some differences between animals. These results identify the specific patterns of activity required to achieve distinct hand postures for grasping, and they open the way to our understanding of how these patterns are generated by the central motor network.
Cerebral Areas Processing Swallowing and Tongue Movement Are Overlapping but Distinct: A Functional Magnetic Resonance Imaging Study
Authors: Martin Ruth E. , MacIntosh Bradley J. , Smith Rebecca C. , Barr Amy M. , Stevens Todd K. , Gati Joseph S. , Menon Ravi S.
Published: May 2004

Although multiple regions of the cerebral cortex have been implicated in swallowing, the functional contributions of each brain area remain unclear. The present study sought to clarify the roles of these cortical foci in swallowing by comparing brain activation associated with voluntary saliva swallowing and voluntary tongue elevation. Fourteen healthy right-handed subjects were examined with single-event–related functional magnetic resonance imaging (fMRI) while laryngeal movements associated with swallowing and tongue movement were simultaneously recorded. Both swallowing and tongue elevation activated 1) the left lateral pericentral and anterior parietal cortex, and 2) the anterior cingulate cortex (ACC) and adjacent supplementary motor area (SMA), suggesting that these brain regions mediate processes shared by swallowing and tongue movement. Tongue elevation activated a larger total volume of cortex than swallowing, with significantly greater activation within the ACC, SMA, right precentral and postcentral gyri, premotor cortex, right putamen, and thalamus. Although a contrast analysis failed to identify activation foci specific to swallowing, superimposed activation maps suggested that the most lateral extent of the left pericentral and anterior parietal cortex, rostral ACC, precuneus, and right parietal operculum/insula were preferentially activated by swallowing. This finding suggests that these brain areas may mediate processes specific to swallowing. Approximately 60% of the subjects showed a strong functional lateralization of the postcentral gyrus toward the left hemisphere for swallowing, whereas 40% showed a similar activation bias for the tongue elevation task. This finding supports the view that the oral sensorimotor cortices within the left and right hemispheres are functionally nonequivalent.
Modulation of Locomotor Activity by Multiple 5-HT and Dopaminergic Receptor Subtypes in the Neonatal Mouse Spinal Cord
Authors: Madriaga M. A. , McPhee L. C. , Chersa T. , Christie K. J. , Whelan P. J.
Published: June 2004

Recently, it has been shown that bath-applied 5-HT can elicit fictive locomotion from perinatal mouse preparations. Since 5-HT acts on multiple receptor subtypes, the focus of this study was to examine which receptor families contribute to the genesis and modulation of locomotor activity. Blockade of 5-HT2 (ketanserin or N-desmethylclozapine) or 5-HT7 receptors (SB-269970) could reversibly block or modulate the locomotor-like pattern. A 5-HT2 agonist (α-methyl-5-HT) was shown to be capable of activating the rhythm. Bath application of 5-HT7 agonists (5-CT) generally led to a tonic increase in neurogram discharge, accompanied by bouts of rhythmic activity. Blockade of dopaminergic receptors {D1 [ R-(+)-SCH-23390 or LE 300]/D2 [(±)-sulpiride or L-741,626] } could reversibly disrupt the rhythm and most effectively did so when the D1 and D2 antagonists were added together. Conversely, 5-HT2 and D1/D2 agonists can interact to evoke locomotor activity. Overall, our data show that, in the neonatal mouse preparation, 5-HT evoked locomotion is partly dependent on activation of 5-HT2, 5-HT7, and dopaminergic receptor subtypes.
Increased measurement accuracy for sequence-verified microarray probes
Authors: Mecham Brigham H. , Wetmore Daniel Z. , Szallasi Zoltan , Sadovsky Yoel , Kohane Isaac , Mariani Thomas J.
Published: June 2004

Microarrays have been extensively used to investigate genome-wide expression patterns. Although this technology has been tremendously successful, it has suffered from suboptimal individual measurement precision. Significant improvements in this respect have been recently made. In an effort to further explore the underlying variability, we have attempted to globally assess the accuracy of individual probe sequences used to query gene expression. For mammalian Affymetrix microarrays, we identify an unexpectedly large number of probes (greater than 19% of the probes on each platform) that do not correspond to their appropriate mRNA reference sequence (RefSeq). Compared with data derived from inaccurate probes, we find that data derived from sequence-verified probes show 1) increased precision in technical replicates, 2) increased accuracy translating data from one generation microarray to another, 3) increased accuracy translating data from oligonucleotide to cDNA microarrays, and 4) improved capture of biological information in human clinical specimens. The logical conclusion of this work is that probes containing the most reliable sequence information provide the most accurate results. Our data reveal that the identification and removal of inaccurate probes can significantly improve this technology.
Real-time RT-PCR analysis of housekeeping genes in human skeletal muscle following acute exercise
Authors: Mahoney Douglas J. , Carey Kate , Fu Ming-Hua , Snow Rodney , Cameron-Smith David , Parise Gianni , Tarnopolsky Mark A.
Published: June 2004

Studies examining gene expression with RT-PCR typically normalize their mRNA data to a constitutively expressed housekeeping gene. The validity of a particular housekeeping gene must be determined for each experimental intervention. We examined the expression of various housekeeping genes following an acute bout of endurance (END) or resistance (RES) exercise. Twenty-four healthy subjects performed either a interval-type cycle ergometry workout to exhaustion (∼75 min; END) or 300 single-leg eccentric contractions (RES). Muscle biopsies were taken before exercise and 3 h and 48 h following exercise. Real-time RT-PCR was performed on β-actin, cyclophilin (CYC), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and β2-microglobulin (β2M). In a second study, 10 healthy subjects performed 90 min of cycle ergometry at ∼65% of V̇o2 max, and we examined a fifth housekeeping gene, 28S rRNA, and reexamined β2M, from muscle biopsy samples taken immediately postexercise. We showed that CYC increased 48 h following both END and RES exercise (3- and 5-fold, respectively; P < 0.01), and 28S rRNA increased immediately following END exercise (2-fold; P = 0.02). β-Actin trended toward an increase following END exercise (1.85-fold collapsed across time; P = 0.13), and GAPDH trended toward a small yet robust increase at 3 h following RES exercise (1.4-fold; P = 0.067). In contrast, β2M was not altered at any time point postexercise. We conclude that β2M and β-actin are the most stably expressed housekeeping genes in skeletal muscle following RES exercise, whereas β2M and GAPDH are the most stably expressed following END exercise.
Genetic linkage of albuminuria and renal injury in Dahl salt-sensitive rats on a high-salt diet: comparison with spontaneously hypertensive rats
Authors: Siegel Anja-Kristin , Kossmehl Peter , Planert Michael , Schulz Angela , Wehland Markus , Stoll Monika , Bruijn Jan A. , de Heer Emile , Kreutz Reinhold
Published: June 2004

Our aim was to study the effects of high-salt diet on the genetics of albuminuria and renal injury in the Dahl salt-sensitive (SS) rat. We compared SS with salt-resistant spontaneously hypertensive rats (SHR) and with genetically related salt-sensitive stroke-prone SHR (SHRSP). Moreover, we performed genome-wide linkage analysis to identify quantitative trait loci (QTL) contributing to salt-induced renal injury in an F2population derived from SS and SHR ( n = 230). In response to high-salt diet SS and SHRSP developed a striking increase in systolic blood pressure, urinary albumin excretion (UAE), and renal damage indices compared with SHR. Both SHRSP and SS developed severe glomerulosclerosis, whereas microangiopathy, tubulointerstitial fibrosis, and inflammation were more pronounced in SHRSP. We detected two QTL with significant linkage to UAE on rat chromosomes (RNO) 6 and 19. Comparison with the recently identified salt-independent UAE QTL in young animals revealed that the UAE QTL on RNO6 is unique to high-salt conditions, whereas RNO19 plays a significant role during both low- and high-salt conditions. Some F2animals demonstrated severe microangiopathy and tubulointerstitial injury, which exceeded the degree observed in the parental SS strain. Three loci demonstrated suggestive linkage to these phenotypes on RNO3, RNO5, and RNO20, whereas no linkage to glomerular damage was found. Further analyses at these loci indicated that the severity of renal injury was attributable to the SHR allele. Our data suggest that the SHR genetic background confers greater susceptibility for the development of microangiopathy and tubulointerstitial injury in salt-sensitive hypertension than the SS background.
Glycan arrays lead to the discovery of autoimmunogenic activity of SARS-CoV
Authors: Wang Denong , Lu Jiahai
Published: June 2004

Using carbohydrate microarrays, we characterized the carbohydrate binding activity of SARS-CoV neutralizing antibodies elicited by an inactivated SARS-CoV vaccine. In these antibodies, we detected undesired autoantibody reactivity specific for the carbohydrate moieties of an abundant human serum glycoprotein asialo-orosomucoid (ASOR). This observation provides important clues for the selection of specific immunologic probes to examine whether SARS-CoV expresses antigenic structures that mimic the host glycan. We found that lectin PHA-L ( Phaseolus vulgaris L.), which is specific for a defined complex carbohydrate of ASOR, stained the SARS-CoV-infected cells specifically and intensively. Taken together, we present immunologic evidence that a carbohydrate structure of SARS-CoV shares antigenic similarity with host glycan complex carbohydrates. The experimental approaches we applied in this study are likely applicable for the identification of immunologic targets of other viral pathogens.
A mixed problem with only integral boundary conditions for ahyperbolic equation
Authors: Bouziani Abdelfatah
Published: June 2004

We investigate an initial boundary value problem for a
second‐order hyperbolic equation with only integral conditions.
We show the existence, uniqueness, and continuous dependence of a
strongly generalized solution. The proof is based on an energy
inequality established in a nonclassical function space, and on
the density of the range of the operator associated to the
abstract formulation of the studied problem by introducing
special smoothing operators.
Behaviour of passage time for a queueing network model withfeedback: a simulation study
Authors: Medya Bidyut K.
Published: June 2004

The study of the queueing system presented in this note was
motivated by its possible application to a multiprogramming
computer system. The paper considers a closed network with two
service centres with feedback. The steady‐state behaviour of the
passage time, the random times for a job to traverse a portion of
the network, is examined through simulation. The model can be
applied to a twin‐processor multiprogramming computer system.
Nonlinear connections and spinor geometry
Authors: Vacaru Sergiu I. , Vicol Nadejda A.
Published: June 2004

We present an introduction to the geometry of higher‐order vector
and covector bundles (including higher‐order generalizations of
the Finsler geometry and Kaluza‐Klein gravity) and review the
basic results on Clifford and spinor structures on spaces with
generic local anisotropy modeled by anholonomic frames with
associated nonlinear connection structures. We emphasize strong
arguments for application of Finsler‐like geometries in modern
string and gravity theory, noncommutative geometry and
noncommutative field theory, and gravity.
S‐plane analysis for the fundamental problems of a stretchedinfinite plate weakened by curvilinear holes
Authors: Ismail I. S.
Published: June 2004

Complex variable methods are used to obtain exact and closed
expressions for Goursat′s functions for the stretched infinite
plate weakened by two inner holes which are free from stresses.
The plate considered is conformally mapped on the area of the
right half‐plane. Previous work is considered as special cases of
this work. Cases of different shapes of holes are
included. Also, many new cases are discussed using this mapping.
Fuzzy multiply positive implicative hyper BCK‐ideals of hyperBCK‐algebras
Authors: Zhan Jianming , Xiang Dajing , Tan Zhisong
Published: June 2004

We consider the fuzzification of the notion of fuzzy multiply
positive implicative hyper BCK‐ideals of
BCK‐algebras and then some related results are
obtained. Using the concept of level subsets, we give a
characterization of a fuzzy multiply positive implicative hyper
BCK‐ideal. We state a relation between a fuzzy hyper
BCK‐ideal and a fuzzy multiply positive implicative
hyper BCK‐ideal. Moreover, we introduce the notions
of Noetherian hyper BCK‐algebras and hyper
homomorphisms of hyper BCK‐algebras and investigate
some related properties. Finally, we introduce the concept of
hyper normalization of hyper BCK‐algebras and
discuss related properties.
Vascular Protection
Authors: Faraci Frank M. , Didion Sean P.
Published: June 2004

Blood vessels express 3 isoforms of superoxide dismutase (SOD): cytosolic or copper-zinc SOD (CuZn-SOD), manganese SOD (Mn-SOD) localized in mitochondria, and an extracellular form of CuZn-SOD (EC-SOD). Because there are no selective pharmacological inhibitors of individual SOD isoforms, the functional importance of the different SODs has been difficult to define. Recent molecular approaches, primarily the use of genetically-altered mice and viral-mediated gene transfer, have allowed investigators to begin to define the role of specific SOD isoforms in vascular biology. This review will focus mainly on the role of individual SODs in relation to endothelium under normal conditions and in disease states. This area is important because reactive oxygen species and superoxide anion are thought to play major roles in changes in vascular structure and function in pathophysiology.
Smad Expression in Human Atherosclerotic Lesions
Authors: Kalinina Natalia , Agrotis Alex , Antropova Yulia , Ilyinskaya Olga , Smirnov Vladimir , Tararak Eduard , Bobik Alex
Published: June 2004

Objective—

Transforming growth factor-beta (TGF-β) has been implicated in the pathogenesis of human atherosclerosis but its actions during lesion progression are poorly understood. Smad2, Smad3, and Smad4 proteins are signaling molecules by which TGF-β modulates gene transcription. Our objective was to define the actions of TGF-β during lesion progression in humans by examining the expression of Smads in relation to TGF-β–mediated responses.

Methods and Results—

Immunohistochemistry and reverse-transcription polymerase chain reaction demonstrated Smad2, Smad3, and Smad4 expression in macrophages of fibrofatty lesions and their upregulation after differentiation of monocytes to macrophages. The major Smad splice variants expressed by the macrophages were those that are transcriptionally most active. Macrophages also expressed cyclin inhibitors whose expression is induced via Smad proteins. The cytoplasmic location of p21
Waf1
suggests it may protect macrophages from apoptosis. Smooth muscle cells (SMCs) within the fibrofatty lesions did not express the Smad proteins or the cyclin inhibitors. SMCs of fibrous plaques expressed all 3 Smad proteins.

Conclusions—

In human atherosclerotic lesions, the actions of TGF-β appear restricted to SMCs in fibrous plaques and macrophages in fatty streaks/fibrofatty lesions. The lack of key TGF-β signaling components in SMCs of fibrofatty lesions indicates impaired ability of these cells to initiate TGF-β–mediated Smad-dependent transcriptional responses.
Lipid Inflammatory Mediators in Diabetic Vascular Disease
Authors: Natarajan Rama , Nadler Jerry L.
Published: June 2004

Type 2 diabetes is associated with significantly accelerated rates of macrovascular complications such as atherosclerosis. Emerging evidence now indicates that atherosclerosis is an inflammatory disease and that certain inflammatory markers may be key predictors of diabetic atherosclerosis. Proinflammatory cytokines and cellular adhesion molecules expressed by vascular and blood cells during stimulation by growth factors and cytokines seem to play major roles in the pathophysiology of atherosclerosis and diabetic vascular complications. However, more recently, data suggest that inflammatory responses can also be elicited by smaller oxidized lipids that are components of atherogenic oxidized low-density lipoprotein or products of phospholipase activation and arachidonic acid metabolism. These include oxidized lipids of the lipoxygenase and cyclooxygenase pathways of arachidonic acid and linoleic acid metabolism. These lipids have potent growth, vasoactive, chemotactic, oxidative, and proinflammatory properties in vascular smooth muscle cells, endothelial cells, and monocytes. Cellular and animal models indicate that these enzymes are induced under diabetic conditions, have proatherogenic effects, and also mediate the actions of growth factors and cytokines. This review highlights the roles of the inflammatory cyclooxygenase and 12/15-lipoxygenase pathways in the pathogenesis of diabetic vascular disease.
Effects of Conventional or Lower Doses of Hormone Replacement Therapy in Postmenopausal Women
Authors: Koh Kwang Kon , Shin Mi-Seung , Sakuma Ichiro , Ahn Jeong Yeal , Jin Dong Kyu , Kim Hyung Sik , Kim Dae Sung , Han Seung Hwan , Chung Wook-Jin , Shin Eak Kyun
Published: June 2004

Objective—

The effects of hormone replacement therapy (HRT) can affect many aspects relevant to cardiovascular disease, including vasomotor function, inflammation, and hemostasis. Recent studies have demonstrated that current doses of HRT exert a mixture of both protective and adverse effects. In the current study, we compared the effects of lower doses of HRT (L-HRT) and conventional doses of HRT (C-HRT) on a variety of relevant cardiovascular parameters.

Methods and Results—

This randomized, double-blind, crossover study included 57 women who received micronized progesterone 100 mg with either conjugated equine estrogen 0.625 mg (C-HRT) or 0.3 mg (L-HRT) daily for 2 months. L-HRT showed comparable effects to C-HRT on high-density lipoprotein cholesterol and triglyceride levels, but not on low-density lipoprotein cholesterol levels. C-HRT and L-HRT significantly improved the percent flow-mediated dilator response to hyperemia from baseline values (both
P
<0.001) by a similar degree (
P
=0.719). C-HRT significantly increased high-sensitivity C-reactive protein (hsCRP) levels from baseline values (
P
<0.001); however, L-HRT did not significantly change hsCRP (
P
=0.874). C-HRT and L-HRT significantly decreased antithrombin III from baseline values (
P
<0.001 and
P
=0.042, respectively). C-HRT significantly increased prothrombin fragment 1+2 (F1+2) from baseline values (
P
<0.001); however, L-HRT did not significantly change F1+2 (
P
=0.558). Of interest, the effects of C-HRT and L-HRT on hsCRP, antithrombin III, and F1+2 were significantly different (all
P
<0.001). C-HRT and L-HRT significantly reduced plasma PAI-1 antigen levels from baseline values (
P
=0.002 and
P
=0.038, respectively) to a similar degree (
P
=0.184).

Conclusions—

Compared with C-HRT, L-HRT has comparable effects on lipoproteins, flow-mediated dilation, and PAI-1 antigen levels. However, L-HRT did not increase hsCRP or F1+2 levels, and it decreased antithrombin III less than C-HRT.
Apolipoprotein B100 Metabolism in Autosomal-Dominant Hypercholesterolemia Related to Mutations inPCSK9
Authors: Ouguerram Khadija , Chetiveaux Maud , Zair Yassine , Costet Philippe , Abifadel Marianne , Varret Mathilde , Boileau Catherine , Magot Thierry , Krempf Michel
Published: June 2004

Objective—We have reported further heterogeneity in familial autosomal-dominant hypercholesterolemia (FH) related to mutation in proprotein convertase subtilisin/kexin type 9 (PCSK9) gene previously named neural apoptosis regulated convertase 1 (Narc-1). Our aim was to define the metabolic bases of this new form of hypercholesterolemia.

Methods and Results—In vivo kinetics of apolipoprotein B100-containing lipoproteins using a 14-hour primed constant infusion of [2H3] leucine was conducted in 2 subjects carrying the mutation S127R inPCSK9, controls subjects, and FH subjects with known mutations on the low-density lipoprotein (LDL) receptor gene (LDL-R). Apo B100 production, catabolism, and transfer rates were estimated from very LDL (VLDL), intermediate-density lipoprotein (IDL), and LDL tracer enrichments by compartmental analysis.PCSK9mutation dramatically increased the production rate of apolipoprotein B100 (3-fold) compared with controls or LDL-R mutated subjects, related to direct overproduction of VLDL (3-fold), IDL (3-fold), and LDL (5-fold). The 2 subjects also showed a decrease in VLDL and IDL conversion (10% to 30% of the controls). LDL fractional catabolic rate was slightly decreased (by 30%) compared with controls but still higher than LDL-R–mutated subjects.

Conclusion—These results showed that the effect of the S127R mutation ofPCSK9on plasma cholesterol homeostasis is mainly related to an overproduction of apolipoprotein B100.
Air Pollution and Cardiovascular Disease
Authors: Brook Robert D. , Franklin Barry , Cascio Wayne , Hong Yuling , Howard George , Lipsett Michael , Luepker Russell , Mittleman Murray , Samet Jonathan , Smith Sidney C. , Tager Ira
Published: June 2004

Air pollution is a heterogeneous, complex mixture of gases, liquids, and particulate matter. Epidemiological studies have demonstrated a consistent increased risk for cardiovascular events in relation to both short- and long-term exposure to present-day concentrations of ambient particulate matter. Several plausible mechanistic pathways have been described, including enhanced coagulation/thrombosis, a propensity for arrhythmias, acute arterial vasoconstriction, systemic inflammatory responses, and the chronic promotion of atherosclerosis. The purpose of this statement is to provide healthcare professionals and regulatory agencies with a comprehensive review of the literature on air pollution and cardiovascular disease. In addition, the implications of these findings in relation to public health and regulatory policies are addressed. Practical recommendations for healthcare providers and their patients are outlined. In the final section, suggestions for future research are made to address a number of remaining scientific questions.
The Clinician as Investigator
Authors: Lader Ellis W. , Cannon Christopher P. , Ohman E. Magnus , Newby L. Kristin , Sulmasy Daniel P. , Barst Robyn J. , Fair Joan M. , Flather Marcus , Freedman Jane E. , Frye Robert L. , Hand Mary M. , Jesse Robert L. , Van de Werf Frans , Costa Fernando
Published: June 2004

The rapid development of new drugs, therapies, and devices has created a dramatic increase in the number of trials needed to properly evaluate them. The majority of patients treated today, many of whom could be eligible for participation in these studies, are seen in community hospitals and medical practices that are not affiliated with an academic medical center. Thus, there is a demonstrable need for physicians in private practice to enlist as investigators in these trials. This article is intended to encourage those physicians by describing the need and providing the rationale for their participation. It covers basic requirements for participating in clinical trials and outlines ethical, regulatory, financial, and other logistical issues of importance for the potential investigator and provides an algorithm for selecting a study for participation. Finally, the appendices review basic elements of study design and statistical principles, which may be of interest to a potential investigator.