bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective dopamine D3 receptor antagonist SB‐277011‐A potentiates phMRI response to acute amphetamine challenge in the rat brain
Authors: Schwarz Adam , Gozzi Alessandro , Reese Torsten , Bertani Simone , Crestan Valerio , Hagan Jim , Heidbreder Christian , Bifone Angelo 
Published: July 2004

AbstractDopamine (DA) receptors are a major target for drugs employed in the treatment of neuropsychiatric disorders such as schizophrenia and drug dependence. The D3 subtype of the D2 DA receptor family presents a particularly focal distribution in limbic brain areas known to be associated with cognitive and emotional functions. This study examined the modulation of brain activation induced by acute administration of amphetamine in the rat by the highly selective DA D3 receptor antagonist SB‐277011‐A using relative cerebral blood volume (rCBV) pharmacological MRI (phMRI). The acute administration of D‐amphetamine (1 mg/kg i.v.) produced a widespread rCBV response that was strongest in cortical regions. SB‐277011‐A (20 mg/kg i.p.) itself did not produce significant changes in rCBV, but potentiated the phMRI response to 1 mg/kg i.v. D‐amphetamine in a regionally specific manner, involving a number of structures outside the focal distribution of the D3 receptor. Potentiated regions included the accumbens, dorsal caudate putamen, islands of Calleja, thalamus, cingulate cortex, ventral tegmental area, dorsal Raphe nucleus, and ventral subiculum. The increased response following D3 receptor antagonism is consistent with this receptor mediating an inhibitory action on brain activity following a dopaminergic stimulus. Synapse 54:1–10, 2004. © 2004 Wiley‐Liss, Inc.
Cocaine alters GABAB‐mediated G‐protein activation in the ventral tegmental area of female rats: Modulation by estrogen
Authors: Febo Marcelo , Segarra Annabell C. 
Published: July 2004

AbstractIn female rats, estrogen has been reported to enhance cocaine sensitization. Here we investigated the effect of estrogen and cocaine treatments on GABAB‐stimulated [35S]GTPγS binding. Ovariectomized rats without (OVX) and with estrogen treatment (OVX‐EB) were pretreated with saline or cocaine (15 mg/kg, i.p.) for 5 days and after 1 week of withdrawal challenged with cocaine. One hour after the final injection, animals were sacrificed, brains immediately frozen, and stored at −70°C for subsequent cryosectioning. In vitro functional autoradiography was performed using baclofen (300 μM), a GABAB receptor agonist, to stimulate [35S]GTPγS binding in tissue sections at the level of the ventral tegmental area (VTA). OVX‐EB rats showed lower levels of [35S]GTPγS binding in the VTA (−15%) and entorhinal cortex (EC) (−60%). The effect of cocaine on GABAB‐mediated G‐protein activation varied with the presence of estrogen. Repeated cocaine administration reduced [35S]GTPγS binding in the VTA and EC of OVX rats and increased it in OVX‐EB. Thus, our data suggest that estrogen reduces GABAB‐mediated G‐protein activation in female rats. The results also show that estrogen strongly influences cocaine‐induced alterations in GABAB function in the VTA and EC of female rats. Synapse 54:30–36, 2004. © 2004 Wiley‐Liss, Inc.
FI Catalysts: new olefin polymerization catalysts for the creation of value‐added polymers
Authors: Mitani Makoto , Saito Junji , Ishii Sei‐ichi , Nakayama Yasushi , Makio Haruyuki , Matsukawa Naoto , Matsui Shigekazu , Mohri Jun‐ichi , Furuyama Rieko , Terao Hiroshi , Bando Hideki , Tanaka Hidetsugu , Fujita Terunori 
Published: July 2004

AbstractThis contribution reports the discovery and application of phenoxy–imine‐based catalysts for olefin polymerization. Ligand‐oriented catalyst design research has led to the discovery of remarkably active ethylene polymerization catalysts (FI Catalysts), which are based on electronically flexible phenoxy–imine chelate ligands combined with early transition metals. Upon activation with appropriate cocatalysts, FI Catalysts can exhibit unique polymerization catalysis (e.g., precise control of product molecular weights, highly isospecific and syndiospecific propylene polymerization, regio‐irregular polymerization of higher α‐olefins, highly controlled living polymerization of both ethylene and propylene at elevated temperatures, and precise control over polymer morphology) and thus provide extraordinary opportunities for the syntheses of value‐added polymers with distinctive architectural characteristics. Many of the polymers that are available via the use of FI Catalysts were previously inaccessible through other means of polymerization. For example, FI Catalysts can form vinyl‐terminated low molecular weight polyethylenes, ultra‐high molecular weight amorphous ethylene–propylene copolymers and atactic polypropylenes, highly isotactic and syndiotactic polypropylenes with exceptionally high peak melting temperatures, well‐defined and controlled multimodal polyethylenes, and high molecular weight regio‐irregular poly(higher α‐olefin)s. In addition, FI Catalysts combined with MgCl2‐based compounds can produce polymers that exhibit desirable morphological features (e.g., very high bulk density polyethylenes and highly controlled particle‐size polyethylenes) that are difficult to obtain with conventionally supported catalysts. In addition, FI Catalysts are capable of creating a large variety of living‐polymerization‐based polymers, including terminally functionalized polymers and block copolymers from ethylene, propylene, and higher α‐olefins. Furthermore, some of the FI Catalysts can furnish living‐polymerization‐based polymers catalytically by combination with appropriate chain transfer agents. Therefore, the development of FI Catalysts has enabled some crucial advances in the fields of polymerization catalysis and polymer syntheses. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 137–158; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20010
Metal‐catalyzed living radical polymerization: discovery and developments
Authors: Kamigaito Masami , Ando Tsuyoshi , Sawamoto Mitsuo 
Published: July 2004

AbstractControl of radical polymerization has been one of the most challenging frontiers in polymerization chemistry. This review presents the discovery of metal‐catalyzed living radical polymerization and recent developments in the evolution of catalysts in terms of versatility and activity, scope of monomers, controlled polymerization in water, catalyst removal, and precision synthesis of well‐controlled polymers such as random, block, end‐functionalized, and star polymers. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 159–175; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20011
A novel electrochemical approach to the characterization of oxidoreductase reactions
Authors: Ikeda Tokuji 
Published: July 2004

AbstractElectrochemical methods based on enzyme‐electrochemical reactions have been developed for studying oxidoreductase reactions. The methods measure a current resulting from an oxidoreductase reaction with an electrode serving as a final electron acceptor (or donor) in the reaction. A theoretical equation for the enzyme‐electrochemical reaction, called bioelectrocatalysis, is derived, which enables kinetic analysis of the reaction. In combination with spectrophotometry, the electrochemical method provides a method for determining the redox potentials of proteins and enzymes. An alternative method based on bulk electrolysis in a quartz cell for UV‐vis spectroscopy has been developed for the measurements of protein redox potentials on a conventional spectrophotometer. The electrochemical methods are applied to kinetic and thermodynamic analyses for the reactions of a variety of enzymes including a newly discovered enzyme, quinohemoprotein amine dehydrogenase (QH‐AmDH), and bilirubin oxidase (BOD) [EC 1.3.3.5, from Myrothecium verrucaria], a copper‐containing enzyme useful for bioelectrocatalytic O2 reduction in biofuel cells. The electrochemical method for kinetic analysis has been successfully applied to the analysis of oxidoreductase reactions in vivo, as demonstrated by the reaction of glucose dehydrogenase in Escherichia coli. The advantages of the electrochemical methods are discussed. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 192–203; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20014
Remote access virtual private network architecture for high‐speed wireless internet users
Authors: Elkeelany O. , Matalgah M. M. , Qaddour J. 
Published: August 2004

AbstractThe new emerging broadband wireless network (BWN) technologies with high‐speed wireless internet access promotes corporations to provide their roaming employees with high‐speed wireless access to the computing resources on their corporate networks. Thus, a value added service to broadband wireless network is the remote access virtual private network (VPN), where the corporate legitimate users can connect to their offices wirelessly from different locations and get secure services as if they were connected to the corporate local area network (LAN). One of the most important challenges is to block out illegitimate user requests, which are wirelessly received, to protect corporate privacy. Registration (adding new users) and authentication (accepting current users) functions should be implemented with highly secured wireless connection. These functions are accomplished by encapsulating (i.e. tunneling) the user information in a secured form to the corporate authentication server through the internet traffic. The corporate authentication server then grants or denies the user access. In this paper, we propose a new operational design algorithm for remote access wireless VPN authentication and registration protocols that depends on modifying tunnel establishment as compared to existing dial‐in VPN mechanisms. The modifications proposed in this paper are made to support successful deployment of the remote access VPN services over high‐speed wireless network. The paper presents an overview of two tunneling approaches using Layer 3 and Layer 2 separately for implementing these functions. Then we propose how we establish the tunnel in both approaches, and compare it to similar operation steps previously reported for the dial‐in VPN protocols. The proposed algorithms are distinguished from previously developed dial‐in VPN protocols by using L2TP and IPSEC instead of mobile IP. It is also shown that the steps involved in the establishment of the tunnel are functionally different and more appropriate to our applications using communication environment of the BWN. Finally, a qualitative analysis of the added functions, and a comparison between L2TP‐based and IPSec‐based approaches are established. Copyright © 2004 John Wiley & Sons, Ltd.
Fundamental limitations of power control and radio resource management in wireless networks
Authors: Gunnarsson Fredrik 
Published: August 2004

AbstractThe ultimate resource in wireless networks is transmission power. The system stability and the resource sharing algorithms all rely on well functioning power control. To realistically address resource management algorithms, it is important to consider fundamental limitations of the radio resource and of power control. Exact and approximate capacity expressions are derived and related to Quality of Service (QoS) requirements of services. Power control is subject to limited update rate, limited feedback bandwidth, time delays, measurement errors, feedback errors and filtering effects which all affect the resulting performance. Simulations further illustrate the hampering effects and motivates models of power control inaccuracies. Copyright © 2004 John Wiley & Sons, Ltd.
Sex‐related bedside clinical variables associated with survival of older inpatients with heart failure
Authors: Cohen Natan , Ilgiyaev Eduard , Almoznino‐Sarafian Dorit , Alon Irena , Shteinshnaider Miriam , Chachashvily Shulamit , Modai David , Gorelik Oleg 
Published: August 2004

AbstractBackground:Little is known about sex‐related differences in factors affecting prognosis of heart failure (HF). We prospectively investigated the relationship between bedside clinical variables and survival of older females vs. males with HF.Methods:Included were consecutive unselected inpatients, age ≥60 years, admitted for various acute conditions. HF was chronic and of diverse etiologies. Follow‐up extended up to 5 years. All‐cause mortality was registered and statistically analyzed for association with in‐hospital clinical variables.Results:Included were 162 females and 200 males. Survival rates were 52.4% and 59%, respectively, (P=0.1). Advanced age and renal dysfunction (RD) were associated with low survival in both sexes (P<0.03 and 0.02, P<0.001 and 0.01, respectively). An association with low survival was found with respect to; admission for pulmonary edema (P<0.02), using furosemide ≥80 mg/day (P<0.005) and severe HF [NYHA class III–IV (P<0.01)] in females, as well as for hypokalemia (P<0.03) and hypocalcemia (P<0.03) in males. On multivariate analysis RD (P<0.001), increasing age (P=0.008) and furosemide dosage ≥80 mg (P=0.02) were most significantly associated with low survival in females, while RD only was significantly associated with low survival in males (P=0.03).Conclusions:Several clinical variables, which affect prognosis in older HF patients are sex‐related and probably carry practical significance.
Bedside tests of B‐type natriuretic peptide in the diagnosis of left ventricular diastolic dysfunction in hypertensive patients
Authors: Wei Tiemin , Zeng Chunlai , Chen Liping , Chen Qunying , Zhao Ruiying , Lu Ganxin , Lu Chunling , Wang Lexin 
Published: August 2004

AbstractAims:To investigate the value of B‐type natriuretic peptide (BNP) in diagnosing left ventricular diastolic dysfunction in patients with hypertension.Methods:The left ventricular diastolic function and plasma BNP levels were assessed prospectively in 135 hypertensive patients.Results:The plasma BNP in patients with (n=61) and without (n=74) diastolic dysfunction was 122±105 and 18±16 pg/ml, respectively (p<0.001). Increased BNP levels were associated with systolic blood pressure (p<0.05), left ventricular mass index (p<0.001), the E/A ratio of transmitral flow (p<0.01) and the isovolumic relaxation time (p<0.01). A receiver‐operator characteristic curve showing the sensitivity and specificity of BNP against the echocardiography diagnosis of diastolic dysfunction revealed an area under the curve (accuracy) of 0.904 (p<0.01). Using a cut‐off value of >40 pg/ml, the sensitivity and specificity of plasma BNP in diagnosing left ventricular diastolic dysfunction were 79% and 92%, respectively.Conclusions:The plasma BNP levels in patients with hypertension are closely related to left ventricular hypertrophy and filling impairment. Plasma BNP may be used to facilitate the diagnosis of left ventricular diastolic dysfunction.
The effects of long‐term β‐blockade on the ventilatory responses to exercise in chronic heart failure
Authors: Witte Klaus K.A. , Thackray Simon , Nikitin Nikolay P. , Cleland John G.F. , Clark Andrew L. 
Published: August 2004

Aims:Chronic heart failure (CHF) patients complain of breathlessness and fatigue. Beta‐blockers improve symptoms, echocardiograpahic variables and prognosis in CHF, but their effect on exercise capacity remains unclear. The aim of this study was to describe the effects of long‐term beta‐blocker therapy on metabolic gas exchange variables and ventilation during exercise in CHF patients.Methods:42 patients with symptomatic heart failure due to left ventricular systolic dysfunction (ejection fraction 33.2 (8.2)) on loop diuretics and angiotensin‐converting enzyme inhibitors or angiotensin II antagonists, underwent exercise testing with metabolic gas exchange. They were then initiated onto and uptitrated to the maximum tolerated dose of beta‐blockers. After 1 year of follow‐up, patients were invited back for repeat testing.Results:35 patients attended for repeat exercise testing. Four patients had died, and three had not tolerated beta‐blockade. After 1 year, exercise time was increased (487 (221) vs. 500 (217), p<0.05), and peak oxygen consumption and VE/VCO2 slope were unchanged (20.9 (5.0) vs. 20.0 (5.4), p=0.15 and 36.7 (8.3) vs. 37.3 (7.8), p=0.70). Peak ventilation, (61.5 (12.9) vs. 57.1 (13.4), p<0.05), peak carbon dioxide production (1629 (404) vs. 1496 (375), p<0.02) and hence respiratory exchange ratio (1.02 (0.08) vs. 0.98 (0.06) p<0.02) and p<0.05) were reduced. Submaximal oxygen consumption and carbon dioxide production were lower at matched workloads. The slope relating symptoms to ventilation (Borg/VE slope) was less steep following beta‐blockade (0.18 (0.09) vs. 0.15 (0.06), p<0.05).Conclusion:Long term beta‐blocker therapy increases exercise time but not peak oxygen consumption, and reduces peak carbon dioxide production. CHF patients are less symptomatic for a given ventilation during exercise following beta‐blocker treatment.
Inhibition of Na+–H+ exchange by cariporide reduces inflammation and heart failure in rabbits with myocardial infarction
Authors: Rungwerth Katrin , Schindler Ursula , Gerl Martin , Schäfer Stefan , Licher Thomas , Busch Andreas E , Ruetten Hartmut 
Published: July 2004

The aim of this study was to assess the effects of the Na+–H+ exchange inhibitor cariporide on left ventricular (LV) morphology and function as well as inflammation in rabbits with heart failure.
Rabbits with myocardial infarction (MI) and sham controls were randomized to receive either standard chow or chow supplemented with cariporide for 9 weeks. LV morphology was determined by echocardiography. LV systolic and diastolic function was assessed under load‐dependent and ‐independent conditions by analysis of LV pressure–volume loops using piezo‐electric crystals.
Plasma concentrations of C‐reactive protein and aldosterone were measured.
Rabbits with MI developed LV dilatation that was reduced by cariporide. Systolic and diastolic LV function was impaired in rabbits with MI when compared to sham, as indicated by a decreased dP/dtmax (MI: 3537±718 mmHg s−1, sham: 5839±247 mmHg s−1, P<0.05), the load‐independent preload recruitable stroke work (PRSW)(MI: 22±7 mmHg, sham: 81±23 mmHg, P<0.05) and a reduction in the time constant of relaxation tau (τ) (MI: 27±1 ms, sham: 17±1 ms, P<0.05), and significantly improved by cariporide (dP/dtmax: 4586±374 mmHg s−1, PRSW: 67±18 mmHg, τ: 20±2 ms; P<0.05 vs MI/control).
Induction of MI was associated with an increase in aldosterone and CRP, indicating activation of the neurohormonal and the inflammatory system that were largely reduced by cariporide.
Cariporide improves LV morphology and function post MI and suppresses inflammation and neurohormonal activation in congestive heart failure (CHF). Na+–H+ exchange inhibition may represent a new pharmaceutical approach for the treatment of CHF.

British Journal of Pharmacology (2004) 142, 1147–1154. doi:10.1038/sj.bjp.0705746
Vanilloid receptors mediate adrenergic nerve‐ and CGRP‐containing nerve‐dependent vasodilation induced by nicotine in rat mesenteric resistance arteries
Authors: Eguchi Shinji , Tezuka Satoko , Hobara Narumi , Akiyama Shinji , Kurosaki Yuji , Kawasaki Hiromu 
Published: July 2004

Previous studies showed that nicotine induces adrenergic nerve‐dependent vasodilation that is mediated by endogenous calcitonin gene‐related peptide (CGRP) released from CGRP‐containing (CGRPergic) nerves. The mechanisms underlying the nicotine‐induced vasodilation were further studied.
Rat mesenteric vascular beds without endothelium were contracted by perfusion with Krebs solution containing methoxamine, and the perfusion pressure was measured with a pressure transducer.
Perfusion of nicotine (1–100 μM) for 1 min caused concentration‐dependent vasodilation. Capsazepine (vanilloid receptor‐1 antagonist; 1–10 μM) and ruthenium red (inhibitor of vanilloid response; 1–30 μM) concentration‐dependently inhibited the nicotine‐induced vasodilation without affecting the vasodilator response to exogenous CGRP.
Nicotine‐induced vasodilation was not inhibited by treatment with 3,4‐dihydroxyphenylalanine (DOPA) receptor antagonist (L‐DOPA cyclohexyl ester; 0.001–10 μM), dopamine D1 receptor‐selective antagonist (SCH23390; 1–10 μM), dopamine D2 receptor antagonist (haloperidol; 0.1–0.5 μM), ATP P2x receptor‐desensitizing agonist (α,β‐methylene ATP; 1–10 μM), adenosine A2 receptor antagonist (8(p‐sulfophenyl)theophylline; 10–50 μM) or neuropeptide Y (NPY)‐Y1 receptor antagonist (BIBP3226; 0.1–0.5 μM).
Immunohistochemical staining of the mesenteric artery showed dense innervation of CGRP‐ and vanilloid receptor‐1‐positive nerves, with both immunostainings appearing in the same neuron. The mesenteric artery was also densely innervated by NPY‐positive nerves. Double immunostainings showed that both NPY and CGRP immunoreactivities appeared in the same neuron of the artery.
These results suggest that nicotine acts on presynaptic nicotinic receptors to release adrenergic neurotransmitter(s) or related substance(s), which then stimulate vanilloid receptor‐1 on CGRPergic nerves, resulting in CGRP release and vasodilation.

British Journal of Pharmacology (2004) 142, 1137–1146. doi:10.1038/sj.bjp.0705773