bluuebunny/crossref_metadata_2025_split huggingface dataset:
ZCZ‐CDMA and OFDMA using M‐QAM for broadband wireless communications
Authors: Weng Jianfeng , Le‐Ngoc Tho , Xu Yinglin 
Published: June 2004

AbstractThis paper considers direct‐sequence code‐division multiple‐access with zero‐correlation zone sequences (ZCZ‐CDMA) and orthogonal frequency‐division multiple‐access (OFDMA) schemes using M‐ary QAM signaling for broadband wireless communications. Their system structures, complexities and performances in both AWGN and multipath frequency‐selective fading channels are evaluated and compared. For ZCZ‐CDMA, joint suppression of the multipath fading interference and multiple‐access interference can be achieved with a reduced family‐size of the spreading sequences. For OFDMA, analytical and simulation results indicate that it has the same performance as ZCZ‐CDMA in fast time‐varying multipath fading channels. In time‐invariant or slowly time‐varying channels, where the channel information can be made available to transmitters, OFDMA outperforms ZCZ‐CDMA, offers a higher capacity and is more flexible for system reconfiguration with a comparable computational complexity. Copyright © 2004 John Wiley & Sons, Ltd.
A queueing model with time‐varying QoS and call dropping for evaluating the performance of CDMA cellular systems
Authors: Liu Bin , Sule Alfa Attahiru 
Published: June 2004

AbstractIn this paper, we present a queueing model to evaluate the performance of CDMA reverse link in a multiple cell environment. Since CDMA capacity is interference limited, both the communication quality of ongoing calls and the admission condition of new arriving calls for each cell depend on the time‐varying signal‐to‐interference ratio (SIR). We use a quasi‐birth‐and‐death process to capture the variation of traffic loads in cells. After obtaining the stationary distribution of the system, we study some important performance indices such as the outage probability of existing calls, the blocking probability of new calls, the average carried traffic in a cell and the dropping frequency of ongoing calls. Numerical results reveal the effects of system parameters on its performance. Copyright © 2004 John Wiley & Sons, Ltd.
Channel‐estimate‐based frequency‐domain equalization (CE‐FDE) for broadband single‐carrier transmission
Authors: Zhang Qing , Le‐Ngoc Tho 
Published: June 2004

AbstractA channel‐estimate‐based frequency‐domain equalization (CE‐FDE) scheme for wireless broadband single‐carrier communications over time‐varying frequency‐selective fading channels is proposed. Adaptive updating of the FDE coefficients are based on the timely estimate of channel impulse response (CIR) to avoid error propagation that is a major source of performance degradation in adaptive equalizers using least mean square (LMS) or recursive least square (RLS) algorithms. Various time‐domain and frequency‐domain techniques for initial channel estimation and adaptive updating are discussed and evaluated in terms of performance and complexity. Performance of uncoded and coded systems using the proposed CE‐FDE with diversity combining in different time‐varying, multi‐path fading channels is evaluated. Analytical and simulation results show the good performance of the proposed scheme suitable for broadband wireless communications. For channels with high‐Doppler frequency, diversity combining substantially improves the system performance. For channels with sparse multi‐path propagation, a tap‐selection strategy used with the CE‐FDE systems can significantly reduce the complexity without sacrificing the performance. Copyright © 2004 John Wiley & Sons, Ltd.
Catecholamines restore myocardial contractility in dilated cardiomyopathy at the expense of increased coronary blood flow and myocardial oxygen consumption (MvO2 cost of catecholamines in heart failure)
Authors: Nikolaidis Lazaros A. , Trumble Dennis , Hentosz Teresa , Doverspike Aaron , Huerbin Rhonda , Mathier Michael A. , Shen You‐Tang , Shannon Richard P. 
Published: June 2004

AbstractTo investigate the metabolic cost of catecholamine use in heart failure, we administered intravenous dobutamine or norepinephrine to dogs with moderate and severe LV dysfunction until LV contractile function was restored to normal levels. Both drugs were associated with significant increases in myocardial O2 consumption, increased coronary blood flow requirements and decreased myocardial mechanical efficiency. These mechanisms may contribute to the deleterious effects of catecholamines in heart failure.
Echocardiographic indices of left ventricular diastolic dysfunction in 647 individuals with preserved left ventricular systolic function
Authors: Pedersen Frants , Raymond Ilan , Madsen Lene H. , Mehlsen Jesper , Atar Dan , Hildebrandt Per 
Published: June 2004

AbstractBackground:Knowledge about the occurrence of isolated diastolic dysfunction (DD) in the general population is limited.Aims:This population study was performed to assess the frequency and distribution pattern of echocardiographic indices of left ventricular (LV) DD in an elderly population aged 50–89 years in which LV systolic function is preserved.Methods and results:The study population (n=764) recruited from the background population answered a heart failure questionnaire and underwent echocardiography. Excluding subjects with a LV ejection fraction <50% or atrial fibrillation, diastolic function was evaluated in 647 subjects. The frequency of impaired relaxation according to earlier guidelines was 0.5%, vs. 2.5% using age‐ and gender‐specific normal values of ‘E/A‐ratio’ and ‘deceleration time’. In a subpopulation of 167 participants, 6.6% had ‘pseudonormalisation’. No difference was found in the frequency of dyspnea in subjects with impaired relaxation or ‘pseudonormalisation’ compared to subjects with normal filling pattern.Conclusion:The prevalence of LV impaired relaxation was highly dependent on the choice of normal (cut‐off) values for Doppler indices. Furthermore, our findings suggest that either isolated DD is often asymptomatic, or that Doppler flow derived parameters as a diagnostic method for assessing DD have a low specificity when used as a screening tool in the general population.
Tolerability of carvedilol and ACE‐Inhibition in mild heart failure. Results of CARMEN (Carvedilol ACE‐Inhibitor Remodelling Mild CHF EvaluatioN)
Authors: Komajda Michel , Lutiger Beatrix , Madeira Hugo , Thygesen Kristian , Bobbio Marco , Hildebrandt Per , Jaarsma Wybren , Riegger Günter , Rydén Lars , Scherhag Armin , Soler‐Soler Jordi , Remme Willem J. ,   On behalf of the CARMEN investigators and co‐ordinators
Published: June 2004

AbstractBackground:Management guidelines for heart failure recommend ACE‐I and β‐blockers. The perception of difficult up‐titration might have added to the slow uptake of β‐blockers despite their mortality and morbidity benefits.Aims:CARMEN offered a possibility to study safety and tolerability of enalapril against carvedilol and their combination.Methods:Five hundred and seventy‐two patients were blindly up‐titrated on carvedilol (target 25 mg bid) and/or enalapril (target 10 mg bid), and continued for 18 months. In the combination arm, carvedilol was up‐titrated before enalapril.Results:There was no group related difference in adverse events during up‐titration. Withdrawal rates were 31, 30 and 30%, and serious adverse events 28, 29 and 34% in the combination, carvedilol and enalapril arms. Mortality was similar in all groups (all‐cause N=14, 14 and 14; cardiovascular N=9, 13 and 14). All‐cause and cardiovascular hospitalizations occurred in 26, 27 and 32%, and in 12, 16 and 22% in the combination, carvedilol and enalapril arms, respectively.Conclusion:The safety profile was similar in all treatment arms. In contrast to common perception, there was no difference in tolerability between the ACE‐I and carvedilol. This result is even more remarkable as the high prestudy use of ACE‐I (65%) might have introduced a bias by selecting ACE‐I tolerant patients, who were only switched from their former ACE‐I to enalapril.
Studies on intragastric PCO2 at rest and during exercise as a marker of intestinal perfusion in patients with chronic heart failure
Authors: Krack Andreas , Richartz Barbara M. , Gastmann Anja , Greim Kasia , Lotze Ulrich , Anker Stefan D. , Figulla Hans R. 
Published: June 2004

AbstractAims:The aim of this study was to investigate mesenteric ischaemia by determining intragastric PCO2 (iPCO2) with gastric tonometry during rest and exercise stress testing in patients with chronic heart failure (CHF). In CHF inflammatory immune activation is hypothesized to result from a chronic endotoxin challenge due to bacterial translocation of hypoperfused intestinal mucosa.Methods and Results:In 10 patients with CHF and ten healthy controls a tonometry catheter was inserted into the stomach. IPCO2 was measured at rest and during bicycle exercise every 5 min. At rest arterial pCO2 (aPCO2), intragastric pCO2 (iPCO2) and the intragastric/arterial gap did not differ between patients and controls. During low level exercise (25 W), patients showed an increase in iPCO2 compared to resting iPCO2, whereas controls did not show an increase in iPCO2 (change in iPCO2: 12±2% vs. 1±0.4%, P<0.001). In CHF, iPCO2 during peak exercise was 25±3% higher than at rest, compared to controls (increase 2±1, P<0.0001).Conclusions:Patients with CHF already at low level exercise develop an increase in iPCO2. This is likely to reflect hypoperfusion of the intestinal mucosa, which may contribute to the development of bacterial translocation.
Clinical characteristics and treatment response in poor and good insight obsessive–compulsive disorder
Authors: Ravi Kishore V. , Samar R. , Janardhan Reddy Y.C. , Chandrasekhar C.R. , Thennarasu K. 
Published: June 2004

AbstractThe DSM-IV criteria recognize the existence of obsessive–compulsive disorder (OCD) with poor insight. However, there is paucity of literature on the clinical correlates and treatment response in poor and good insight OCD. In this study, insight is measured by using the Brown Assessment of Beliefs Scale (BABS) developed specifically to assess insight. One hundred subjects with DSM-IV OCD were ascertained from the OCD clinic of a large psychiatric hospital in India. All subjects were evaluated extensively by using structured instruments and established measures of psychopathology. The subjects were treated with adequate doses of drugs for adequate period. The results showed that 25% of the subjects had poor insight. Poor insight was associated with earlier age-at-onset, longer duration of illness, more number of obsessive–compulsive symptoms, more severe illness and higher comorbidity rate, particularly major depression. Of the subjects who were treated adequately (N = 73), 44 (60%) were treatment responders. Poor insight was associated with poor response to drug treatment. In the step-wise logistic regression analysis, baseline BABS score was highly predictive of poor treatment response. Poor insight appears to be associated with specific clinical correlates and poor response to drug treatment. Further studies are needed in larger samples to replicate our findings.
Effect of adrenalectomy and corticosterone replacement on prepulse inhibition and locomotor activity in mice
Authors: Van Den Buuse Maarten , Morris Margaret , Chavez Carolina , Martin Sally , Wang JianHong 
Published: June 2004

Stress is a risk factor in psychiatric illnesses such as schizophrenia. The aim of the present study was to investigate the effect of different circulating levels of the adrenal steroid corticosterone (CORT) on locomotor hyperactivity and prepulse inhibition of acoustic startle, two behavioural animal models of aspects of schizophrenia.
Male C57BL/6J mice (n=10 per group) were anaesthetised with isoflurane and sham‐operated or adrenalectomised (ADX). ADX mice were implanted with 50 mg pellets consisting of 100% cholesterol, or 2, 10 or 50 mg of CORT mixed with cholesterol. CORT pellet implantation dose dependently increased plasma CORT levels 3 weeks after surgery. Starting 1 week after surgery, mice were tested for prepulse inhibition after injection of saline or 5 mg kg−1 of haloperidol.
In intact mice and in mice implanted with 10 mg of CORT, haloperidol treatment significantly increased prepulse inhibition (average values from 38 – 42 to 52%). Similar results were observed when testing the mice for amphetamine‐induced locomotor hyperactivity (5 mg kg−1). In contrast, there was no significant effect of haloperidol in mice implanted either with cholesterol or 2 or 50 mg of CORT.
These results in behavioural animal models of schizophrenia suggest an important role of the stress hormone CORT in modulating dopaminergic activity in this illness.

British Journal of Pharmacology (2004) 142, 543–550. doi:10.1038/sj.bjp.0705511
Protective effect of edaravone against hypoxia–reoxygenation injury in rabbit cardiomyocytes
Authors: Yamawaki Masahiro , Sasaki Norihito , Shimoyama Masaki , Miake Junichiro , Ogino Kazuhide , Igawa Osamu , Tajima Fumito , Shigemasa Chiaki , Hisatome Ichiro 
Published: June 2004

We examined whether edaravone (Eda), a clinically available radical scavenger, directly protects cardiomyocytes from ischemia/reperfusion (I/R) injury, and whether the timing of its application is critical for protection.
Cardioprotective effects of edaravone were tested in the modified cell‐pelleting model of ischemia and under exogenous oxidative stress (hydrogen peroxide: H2O2) in isolated adult rabbit ventricular cells. Cell death and reactive oxygen species (ROS) generation were detected using propidium iodide (PI) and DCFH‐DA, respectively. These parameters were evaluated objectively using flow cytometory.
Hypoxia and reoxygenation aggravated the proportion of dead cells from 32.2±1.8% (Baseline) to 51.3±2.7% (Control). When 15 μM edaravone was applied either throughout the entire experiment (Through) or only at reoxygenation (Reox), cell death was significantly reduced to 39.9±1.8% (P<0.01 vs Control) and 43.3±2.5% (P<0.05 vs Control), respectively. In contrast, when edaravone was applied 10 min after reoxygenation, its protective effect disappeared. Cardioprotection by edaravone was more remarkable than that afforded by other free radical scavengers, such as ascorbate and superoxide dismutase (SOD). There is a positive correlation between the cardioprotective effect of edaravone and the extent of ROS reduction.
Edaravone blunted the H2O2‐induced changes in electrical properties, and significantly prolonged the time to contracture induced by H2O2 in single ventricular myocytes.
Taken together, edaravone directly protects cardiomyocytes from I/R injury by attenuating ROS production, even when applied at the time of reoxygenation, suggesting that edaravone could be a potent cardioprotective therapeutic agent against hypoxia–reoxygenation injury.

British Journal of Pharmacology (2004) 142, 618–626. doi:10.1038/sj.bjp.0705775
LNP 906, the first high‐affinity photoaffinity ligand selective for I1 imidazoline receptors
Authors: Dragan Urosevic , Stephan Schann , Jean‐Daniel Ehrhardt , Pascal Bousquet , Hugues Greney 
Published: June 2004

The hypotensive effect of imidazoline‐like drugs, such as clonidine, was attributed both to α2‐adrenergic receptors and nonadrenergic imidazoline receptors, which are divided into I1, I2 and I3 subtypes.
We have recently synthesized a derivative of (2‐(2‐chloro‐4‐iodo‐phenylamino)‐5‐methyl‐pyrroline (LNP 911), the first high‐affinity and selective ligand for I1 receptors (I1R), with a photoactivable function (LNP 906).
This work aims to test whether this derivative retained the binding properties of LNP 911 and bound irreversibly to I1R.
Binding studies showed that LNP 906 exhibited nanomolar affinity for I1R and was selective for I1R over I2 receptors and α2‐adrenergic receptors (α2Ars).
Upon exposure to u.v. light, LNP 906 irreversibly blocked the binding of [125I]‐paraiodoclonidine (PIC) to I1R, time‐ and dose‐dependently, on PC12 cell membranes and interacted with I1R in a reversible and competitive manner in the absence of light. Pharmacological studies showed that this blockade was prevented by the concomitant presence of rilmenidine (a well‐known I1 agonist), but not by rauwolscine (an α2 antagonist).
Finally, LNP 906 clearly antagonized the decrease in forskolin‐stimulated cAMP level induced by rilmenidine, but not by melatonin.
These results indicate that LNP 906 is the first high‐affinity and selective photoaffinity ligand for I1R and that it behaves as an I1R antagonist.

British Journal of Pharmacology (2004) 142, 609–617. doi:10.1038/sj.bjp.0705784
Functional M3 muscarinic acetylcholine receptors in mammalian hearts
Authors: Wang Zhiguo , Shi Hong , Wang Huizhen 
Published: June 2004

In contrast to most peripheral tissues where multiple subtypes of muscarinic acetylcholine receptor (mAChR) coexist, with each of them playing its part in the orchestra of parasympathetic innervation, the myocardium has been traditionally considered to possess a single mAChR subtype. Although there is much evidence to support the notion that one receptor subtype (M2) orchestrates myocardial muscarinic transduction, there is emerging evidence that M1 and M3 receptors are also expressed and are of potential physiological, pathophysiological and pharmacological relevance. Clarifying this issue has a profound impact on our thinking about the cholinergic control of the heart function and disease and approaches to new drug development for the treatment of heart disease associated with parasympathetic dysfunction. This review article presents evidence for the presence of the M3 receptor subtype in the heart, and analyzes the controversial data from published pharmacological, functional and molecular studies. The potential roles of the M3 receptors, in parasympathetic control of heart function under normal physiological conditions and in heart failure, myocardial ischemia and arrhythmias, are discussed. On the basis of these considerations, we have made some proposals concerning the future of myocardial M3 receptor research.British Journal of Pharmacology (2004) 142, 395–408. doi:10.1038/sj.bjp.0705787
Influence of sodium substitutes on 5‐HT‐mediated effects at mouse 5‐HT3 receptors
Authors: Barann M , Schmidt K , Göthert M , Urban B W , Bönisch H 
Published: June 2004

The influence of sodium ion substitutes on the 5‐hydroxytryptamine (5‐HT)‐induced flux of the organic cation [14C]guanidinium through the ion channel of the mouse 5‐HT3 receptor and on the competition of 5‐HT with the selective 5‐HT3 receptor antagonist [3H]GR 65630 was studied, unless stated otherwise, in mouse neuroblastoma N1E‐115 cells.
Under physiological conditions (135 mM sodium), 5‐HT induced a concentration‐dependent [14C]guanidinium influx with an EC50 (1.3 μM) similar to that in electrophysiological studies.
The stepwise replacement of sodium by increasing concentrations of the organic cation hydroxyethyl trimethylammonium (choline) concentration dependently caused both a rightward shift of the 5‐HT concentration–response curve and an increase in the maximum effect of 5‐HT. Complete replacement of sodium resulted in a 34‐fold lower potency of 5‐HT and an almost two times higher maximal response. A low potency of 5‐HT in choline buffer was also observed in other 5‐HT3 receptor‐expressing rodent cell lines (NG 108‐15 or NCB 20).
Replacement of Na+ by Li+ left the potency and maximal effects of 5‐HT almost unchanged. Replacement by tris (hydroxymethyl) methylamine (Tris), tetramethylammonium (TMA) or N‐methyl‐D‐glucamine (NMDG) caused an increase in maximal response to 5‐HT similar to that caused by choline. The potency of 5‐HT was only slightly reduced by Tris, to a high degree decreased by TMA (comparable to the decrease by choline), but not influenced by NMDG.
The potency of 5‐HT in inhibiting [3H]GR65630 binding to intact cells was 35‐fold lower when sodium was completely replaced by choline, but remained unchanged after replacement by NMDG.
The results are compatible with the suggestion that choline competes with 5‐HT for the 5‐HT3 receptor; the increase in maximal response may be partly due to a choline‐mediated delay of the 5‐HT‐induced desensitization. For studies of 5‐HT‐evoked [14C]guanidinium flux through 5‐HT3 receptor channels, NMDG appears to be an ‘ideal’ sodium substituent since it increases the signal‐to‐noise ratio without interfering with 5‐HT binding.

British Journal of Pharmacology (2004) 142, 501–508. doi:10.1038/sj.bjp.0705788
Noladin ether, a putative endocannabinoid, attenuates sensory neurotransmission in the rat isolated mesenteric arterial bed via a non‐CB1/CB2 Gi/o linked receptor
Authors: Duncan Marnie , Millns Paul , Smart Darren , Wright James E , Kendall David A , Ralevic Vera 
Published: June 2004

Noladin ether has recently been reported to be an endocannabinoid, with selectivity for the cannabinoid (CB) CB1 receptor. In the present study, we investigated the effects of noladin ether in the rat isolated mesenteric arterial bed, cultured dorsal root ganglia (DRG) cells and human vanilloid (TRPV1)‐receptor‐expressing HEK293 cells (TRPV1‐HEK293 cells).
Electrical field stimulation of the mesenteric bed evoked frequency‐dependent vasorelaxation due to the action of calcitonin gene‐related peptide (CGRP) released from sensory nerves. Noladin ether (0.1–3 μM) attenuated sensory neurogenic relaxation in a concentration‐dependent manner. Noladin ether (1 μM) reduced vasorelaxation at a submaximal frequency (8 Hz), from 57.3±6.8 to 23.3±3.8% (P<0.05, n=4).
The inhibitory effects of noladin ether were unaffected by the CB1 antagonists SR141716A and LY320135, and the CB2 antagonist SR144528 (1 μM).
Noladin ether had no effect on vasorelaxation elicited by exogenous CGRP or capsaicin. These data suggest that noladin ether is acting at a prejunctional site and no interaction with TRPV1 is involved.
In mesenteric beds from pertussis toxin (PTX)‐pretreated rats, the inhibitory actions of noladin ether on sensory neurotransmission were abolished, indicating the involvement of Gi/o protein‐coupled receptors.
Noladin ether evoked a concentration‐dependent increase in intracellular Ca2+ concentration in TRPV1‐HEK293 cells at 10 μM (36.5±3.2% of maximal capsaicin‐induced response), but it was a less potent agonist than both capsaicin and anandamide and at 1 μM it was essentially inactive. Noladin ether (1 μM) had no effect on capsaicin‐evoked Ca2+ responses in DRG cells, and produced no response alone, indicating it neither modulates nor acts directly on TRPV1 receptors.
These data demonstrate that noladin ether attenuates sensory neurotransmission in rat mesenteric arteries via a non‐CB1 non‐CB2 PTX‐sensitive prejunctional site, independently of TRPV1 receptors.

British Journal of Pharmacology (2004) 142, 509–518. doi:10.1038/sj.bjp.0705789