bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluoxetine‐induced pressor response in freely moving rats: a role for vasopressin and sympathetic tone
Authors: Lazartigues Eric , Brefel‐Courbon Christine , Bagheri Haleh , Costes Sandrine , Gharib Claude , Tran Marie‐Antoinette , Senard Jean‐Michel , Montastruc Jean‐Louis
Published: August 2009

Abstract— The present study was performed in order to assess, in freely moving rats, the cardiovascular effects of central administration of fluoxetine, a serotonin reuptake inhibitor. Two kinds of experiments were performed: 1) acute central administration of fluoxetine, and 2) chronic intraperitoneal administration of fluoxetine plus selegiline, a monoamine oxidase B inhibitor. Intracerebroventricular (i.c.v.) administration of fluoxetine (5–50 μg) induced an increase in blood pressure. This fluoxetine‐induced pressor response reached its maximal 1 hour after injection without any significant change in heart rate. At the dose of 10 μg i.c.v., fluoxetine significantly increased mean blood pressure by 16 ± 4 mmHg. This pressor response was reduced by an intravenous (i.v.) pretreatment with the α1‐adrenoceptor antagonist, prazosin (500 μg kg−1) (+ 7 ± 4 mmHg, P < 0.05) or with the V1A‐vasopressin receptor antagonist (20 μg kg−1) (+ 5 ± 3 mmHg, P < 0.05). The pressor response was completely abolished by a concomitant pretreatment with prazosin plus the V1A‐vasopressin receptor antagonist. Pretreatment with the β‐adrenoceptor antagonist, propranolol (1 mg kg−1i.v.), or the 5‐HT2 receptor antagonist, ketanserine (5 mg kg−1i.v.), did not modify the fluoxetine‐induced pressor response. In freely moving rats receiving fluoxetine (10 μg i.c.v.), vasopressin plasma levels were significantly higher (39 ± 5 pg mL−1) than in rats receiving 10 μL i.c.v. saline (14 ± 4 pg mL−1). A 30 day intraperitoneal (i.p.) administration of fluoxetine in association with selegiline induced an increase in noradrenaline plasma levels and locomotor activity without any significant change in blood pressure and heart rate. These data suggest that, the pressor response elicited by central acute administration of fluoxetine is mediated by both an increase in sympathetic tone and vasopressin release. This observation could suggest the putative interest of α1‐adrenoceptor and/or V1A‐vasopressin receptor antagonists in the treatment of “Serotonin Syndrome”.
Clotrimazole inhibits smooth muscle cell proliferation and has a vasodilator effect on resistance arteries
Authors: Raicu Monica , Florea Stela , Costache Gabriela , Popov Doina , Simionescu Maya
Published: August 2009

Abstract— Clotrimazole (CLT) is a drug known to interfere with cellular calcium homeostasis, which in turn is reported to intervene in cell proliferation and in the reactivity of small blood vessels. Experiments were designed to test the influence of CLT on the proliferative and vasorelaxant effect of bradykinin (BK) and on calcium homeostasis in smooth muscle cells (SMC). To this purpose two model systems were employed: (i) cultured human smooth muscle cells (HSMC), and (ii) isolated resistance arteries maintained in an organ bath. The effect of various concentrations of CLT (2–15 μM) on BK‐induced proliferation of HSMC was quantitated by spectrometry following [3H]‐thymidine incorporation, and intracellular calcium [Ca2+]i was determined by spectrofluorimetry using Fura 2‐AM assay. In other experiments the roles of BK receptor (AB2) and of thapsigargin were assessed. The reactivity of the resistance arteries was measured by the myograph technique, and the effects of BK, CLT, and NO synthase blocker, L‐NAME were evaluated. The results showed that 10 μM CLT: (i) inhibits the BK‐induced proliferation of HSMC by 45–50%; (ii) prevents the rise of[Ca2+]i induced by BK (120.8 ± 12.4 nM vs. 235.8 ± 34.1 nM), an effect similar to that of “classic” L‐type calcium channels blockers; (iii) reduces the release of Ca2+entry induced by thapsigargin suggesting a possible inhibition of the capacitative Ca2+entry. Organ bath assays showed that CLT enhanced the BK‐induced relaxation of the resistance arteries by an endothelium NO‐independent pathway. Together, these data suggest that the mechanism of action of CLT on SMC implies mainly a modification of intracellular calcium homeostasis, with a minor contribution of BK B2 receptors. These new distinctive features of CLT effects suggest the potential use of this drug in the therapy of cardiovascular diseases associated with SMC increased proliferation and impeded relaxation in small arteries, such as atherosclerosis and restenosis.
Low glucocorticoid concentrations decrease oxidative phosphorylation of isolated rat brain mitochondria: an additional effect of dexamethasone
Authors: Morin Christophe , Zini Roland , Simon Nicolas , Charbonnier Peggy , Tillement Jean‐Paul , Louet Hervé Le
Published: August 2009

Abstract— The effects of hydrocortisone, triamcinolone, prednisolone and dexamethasone have been investigated in vitro using mitochondria isolated from rat brain. Respiratory control ratio (RCR). oxygen consumption. ATP synthesis, enzymatic activities of involved complexes and superoxide anion generation have been measured to assess the effects of these drugs. Our data showed that the decrease of RCR induced by glucocorticoids was due to a common inhibition of oxidative phosphorylation (State 3) and of complex V activity and a modification of the proton‐fluxes through the mitochondrial inner membrane. These effects were quantitatively limited, since they occurred at concentrations lower than 2 nM. Dexamethasone was the only one able to induce a specific inhibition of complex I activity and to decrease the superoxide anion radical generation. Inhibition of complex V and partial reversion of uncoupling seem to be common properties of glucocorticoids. The theoretical consequence of these inhibitions could be the modulation of the mitochondrial function, oxygen consumption rate. ATP synthase activity and superoxide anion radical production, involved in many patho‐physiological phenomena.
Induction and inhibition of cicletanine metabolism in cultured hepatocytes and liver microsomes from rats
Authors: Menard Christophe , Lamiable Denis , Vistelle Richard , Morin Elisabeth , Ratanasavanh Damrong
Published: August 2009

Abstract— Cicletanine, a racemic furopyridine derivative synthesized as racemate, is used as an antihypertensive agent. Its two enantiomers are involved in the pharmacological effects of the drug. Cicletanine is metabolized by conjugation enzyme systems (phase II) into sulfoconjugated or glucuroconjugated enantiomers. This study reports on the use of both the induction with 3‐methylcholanthrene (3‐MC) or phenobarbital (PB) and inhibition with selective compounds to determine and identify UGT isoenzymes involved in the metabolism of cicletanine enantiomers. PB and 3‐MC both enhanced the cicletanine enantiomer glucuronidation. These two compounds being known as inducing agents of UGT2B1 and UGT1A6 isoforms, respectively, this suggests an implication of UGT2B1 and UGTIA6 isoforms in the metabolism of the two cicletanine enantiomers: (+)‐cicletanine and (‐)‐cicletanine. The use of selective compounds for inhibition study evidenced, in addition to UGT2BI and UGT1A6 isoforms, the involvement of other UGT isoforms such as UGTIAI, UGT2B7 and UGT2B15 in cicletanine metabolism.
Cardiovascular effects of chronic ifenprodil in a model of central sympathetic stimulation
Authors: Catelli Marcelo , Monassier Laurent , Feldman Josiane , Tibiriçá Eduardo
Published: August 2009

Abstract— In the present study we investigated the effects of a long‐term treatment (14 days) with ifenprodil on the excitatory haemodynamic responses induced by central pharmacological stimulation in anaesthetised rabbits. The intracerebroventricular injection of L‐glutamate (3 mg/kg) induced important rises in dP/dtmax (32.9%), mean arterial pressure (42.6%) and in the myocardial oxygen consumption index: the triple product (84.2%). Ifenprodil (1.5, 3 and 6 mg/kg/day, i.p.) reduced the increases in myocardial oxygen demand induced by intracerebral L‐glutamate in a dose‐related manner. Interestingly, ifenprodil also reduced in a dose‐dependent manner the maximum values of the oxygen demand indices reached during the central nervous system stimulation. These results indicate that the long‐term treatment with ifenprodil can reduce the myocardial oxygen consumption induced by central nervous system stimulation without significant depression of the resting cardiac function. This favourable effect of ifenprodil is in fact a consequence of the association of mild inhibitory effects on the three parameters taken into account in the triple product index of myocardial oxygen consumption.
Calcium and bicarbonate ions mediate the inhibition of mast cell histamine release by Avène spa water
Authors: Joly Francine , Galoppin Lysiane , Bordat Pascal , Cousse Henri , Neuzil Eugène
Published: August 2009

Abstract— Avène spa water (ASW) inhibits the histamine release induced in mast cells by substance P; the inhibition is reversed by EDTA and by EGTA. Calcium and magnesium ions, the major cations present in ASW, were experimented in simple saline solutions in the presence of various counter‐ions. Only calcium salts inhibited the peptidergic stimulation, with different potencies ruled by the nature of the counter‐anion (HCO3‐> Cl‐> SO24). On a Ca2+concentration basis, ASW was, however, more inhibitory, suggesting that other compounds present in ASW potentiate the effect of calcium.
Provision of NHS‐funded spectacles in South London
Authors: Jessa Zahra , Evans Bruce J.W. , Thomson David W. , Rowlands Gill
Published: August 2009

Background:  In the UK the National Health Service (NHS) funds primary eyecare in the form of General Ophthalmic Services (GOS) mostly via ‘sight tests’ with community optometrists. Eligible groups include those aged 60 years or more and many are also entitled to an NHS optical voucher to be used to fund spectacles. Only some optical practices provide spectacles whose cost is fully covered by the voucher value which we describe as voucher value spectacles (VVS). As part of a larger study investigating vision screening in the older population, we sought to investigate the proportion of practices that provide VVS.

Methods:  A questionnaire was sent to all optical practices in South London and also a more national sample of optometrists using the UK optometry e‐mail discussion list.

Results:  All 75 respondents provide NHS sight tests. VVS were provided by 59% of the total sample (70% of the South London sample). For those who supply VVS, the number of frames that were provided for patients to choose from ranged from 1 to 100, with a median of 16.5. Of those practitioners who did not supply VVS, 13% provided spectacles whose lens cost was fully covered by the NHS Voucher.

Discussion:  In South London nearly a third of the practices do not provide VVS and it has been suggested that this is because the voucher values are uneconomic. The limited availability of VVS may act as one of the barriers that result in so many older people in the UK having poor vision simply through lack of appropriate spectacles.
Morphospace occupation in thalattosuchian crocodylomorphs: skull shape variation, species delineation and temporal patterns
Authors: PIERCE STEPHANIE E. , ANGIELCZYK KENNETH D. , RAYFIELD EMILY J.
Published: August 2009

Abstract: Skull shape variation in thalattosuchians is examined using geometric morphometric techniques in order to delineate species, especially with respect to the classification of Callovian species, and to explore patterns of disparity during their evolutionary history. The pattern of morphological diversity in thalattosuchian skulls was found to be very similar to modern crocodilians: the main sources of variation are the length and the width of the snout, but these broad changes are correlated with size of supratemporal fenestra and frontal bone, length of the nasal bone, size of the orbit and premaxilla and position of the narial opening. Patterns of shape variation, in combination with discrete‐state morphology and stratigraphic and geographic range data were used to distinguish nine species of teleosaurid and 14 species of metriorhynchid, with the four currently recognized Callovian species being split into eight. Metriorhynchids were found to be more disparate from the average shape of morphospace than teleosaurids. However, short‐snouted metriorhynchids and long‐snouted teleosaurids showed the greatest amount of disparity with respect to snout morphotypes, indicating that each group tended to explore opposite areas of morphospace. Phylogeny was found to have a moderate influence on the pattern of morphospace occupation in metriorhynchids, but little effect in teleosaurids suggesting that other factors or constraints control the pattern of skull shape variation in thalattosuchians. A comparison of thalattosuchians with dyrosaur/pholidosaurids shows that thalattosuchians have a unique skull morphology, implying that there are multiple ways to construct a ‘long snout’. Moreover, the skull geometry of the problematic speciesPelagosaurus typuswas found to converge on the teleosaurid area of morphospace. Finally, the temporal distribution of thalattosuchian species and morphotypes demonstrate a clear and highly correlated relationship with sea level curves and mass extinction events through the Jurassic and the Early Cretaceous.
META‐ANALYSIS OF GRAZER CONTROL OF PERIPHYTON BIOMASS ACROSS AQUATIC ECOSYSTEMS1
Authors: Hillebrand Helmut
Published: August 2009

Grazer control of periphyton biomass has been addressed in numerous experimental studies in all kinds of aquatic habitats. In this meta‐analysis, the results of 865 experiments are quantitatively synthesized in order to address the following questions: (i) Do lotic, lentic, and marine ecosystems differ in their degree of grazer control of periphyton biomass? (ii) Which environmental variables affect the degree of grazer control? (iii) How much does the result of these experiments depend on facets of experimental design? Across all ecosystems, the grazers removed on average 59% of the periphyton biomass, with grazing being significantly stronger for laboratory (65%) than for field (56%) experiments. Neither field nor lab experiments showed a significant difference among lotic, lentic, and coastal habitats. Among different taxonomic consumer groups, crustaceans (amphipods and isopods) and trichopteran larvae removed the highest proportion of periphyton biomass. Grazer effects increased with increasing algal biomass, with decreasing resource availability and with increasing temperature, especially in field experiments. Grazer effects also increased with increasing total grazer biomass in field experiments but showed the opposite trend in lab experiments, indicating a tendency toward overcrowded lab experiments. Other aspects of experimental design, such as cage type, size, and duration of the study, strongly affected the outcome of the experiments, suggesting that much care has to be placed on the choice of experimental design.
MIXOTROPHIC ALGAE CONSTRAIN THE LOSS OF ORGANIC CARBON BY EXUDATION1
Authors: Kamjunke Norbert , Tittel Jörg
Published: August 2009

Algae of various taxonomic groups are capable of assimilating dissolved organic carbon (DOC) from their environments (mixotrophy). Recently, we reported that, with increasing biomass of mixotrophs, heterotrophic bacteria did not increase. We hypothesized that algal uptake of external DOC may outweigh their release of DOC by exudation (H1). Here, we addressed an alternative hypothesis that algae did not assimilate external DOC but constrained the release of DOC (H2). In chemostat experiments, we cultured the mixotrophic Chlamydomonas acidophila Negoro together with heterotrophic bacteria. As external substrates, we used glucose, which was potentially available for both bacteria and algae, or fructose, which was available only for bacteria. We increased the biomass of algae by the stepwise addition of phosphorus. Bacterial biomass did not increase in experiments using glucose or when fructose was offered, suggesting that mechanisms other than algal mixotrophy (H1) kept concentrations of bacteria low. Measured exudation rates (percent extracellular release, PER) of mixotrophic algae (Cd. acidophila, Chlorella protothecoides W. Krüger) were very low and ranged between 1.0% and 3.5% at low and moderately high phosphorus concentrations. In contrast, an obligately phototrophic alga (Chlamydomonas segnis H. Ettl) showed higher exudation rates, particularly under phosphorus limitation (70%). The results support H2. If mixotrophy is considered as a mechanism to recycle organic exudates from near the cell surface, this would explain why algae retained mixotrophic capabilities although they cannot compete with bacteria for external organic carbon.
CELL‐WALL DEVELOPMENT AND BIPOLAR GROWTH IN THE DESMID PENIUM MARGARITACEUM (ZYGNEMATOPHYCEAE, STREPTOPHYTA). ASYMMETRY IN A SYMMETRIC WORLD1
Authors: Domozych David S. , Lambiasse Laura , Kiemle Sarah N. , Gretz Michael R.
Published: August 2009

Cell‐wall (CW) development in the desmid Penium margaritaceum (Ehrenb.) Bréb. was studied using immunofluorescence labeling of living cells with the monoclonal antibodies (mAbs) JIM5 and JIM7, which recognize unesterified and methyl‐esterified homogalacturonan (HG), respectively. During cell expansion, HG was secreted in a high‐esterified form at a narrow band, called the HG secretion band or HGSB, at the isthmus or the polar tip of a daughter semicell. As newly secreted HG is displaced outward on the cell surface, deesterification and subsequent calcium (Ca2+)‐complexing occurred to yield a rigid covering. HG secretion and CW/cell expansion were reversibly inhibited by dark, brefeldin A (BFA), and incubation in 0.24–0.36 M sucrose but were not altered by treatment with actin/microfilament drugs. The HGSB was detected near the nucleus during most cell‐cycle events. Centrifugation displaced the nucleus away from the HGSB, but HG synthesis was not affected. HGSB activity was preceded by, and coordinated with, Calcofluor labeling, which suggests that cellulose production in CW/cell‐expansion sites was critical to expansion control. In many first‐cell‐division products, asymmetric patterning of HG was noted in the CW. These asymmetric patterns most likely were a result of timing mechanisms and displacement of the nucleus‐HGSB during the cell cycle.
RECENT VERSUS RELIC: DISCERNING THE GENETIC SIGNATURE OF FUCUS VESICULOSUS (HETEROKONTOPHYTA; PHAEOPHYCEAE) IN THE NORTHWESTERN ATLANTIC1
Authors: Muhlin Jessica F. , Brawley Susan H.
Published: August 2009

Fucus vesiculosus L. is one of the most widespread macrophytes in the northwestern Atlantic, ranging from North Carolina (USA) to Greenland (DK). We investigated genetic diversity, population differentiation, patterns of isolation by distance, and putative glacial refugial populations across seven locations from North Carolina (USA) to Cape Breton Island, Nova Scotia (Canada), with microsatellite analyses. Distinct northern versus southern (Delaware–North Carolina) populations were revealed by microsatellite data. Five of six microsatellite loci were fixed in populations in North Carolina, suggesting a recent founder event or a bottleneck, and the same homozygous genotype was found in herbarium materials collected on the North Carolina coast from more than 60 years ago. An additional set of individuals from the northern limit in Greenland was included in our analysis of mitochondrial intergenic spacer (mt IGS) haplotypes in the northwestern Atlantic. Remarkably, 184 of 188 F. vesiculosus specimens from North Carolina to Greenland shared the same haplotype. Recent colonization of the North American shore from Europe is hypothesized based upon the ubiquity of this common haplotype, which was earlier reported from Europe.
A SCAR MOLECULAR MARKER SPECIFICALLY RELATED TO THE FEMALE GAMETOPHYTES OF SACCHARINA (LAMINARIA) JAPONICA (PHAEOPHYTA)1
Authors: Liu Y.‐S. , Li L.‐H. , Wu W.‐K. , Zhou Z.‐G.
Published: August 2009

PCR amplification was employed to identify female or male gametophyte associated markers in Saccharina japonica (Aresch.) C. E. Lane, C. Mayes et G. W. Saunders (=Laminaria japonica Aresch.). One pair of the primers, P5, was screened from five pairs designed based on a specific sequence (GenBank accession no. AB069714) of Marchantia polymorpha Y chromosome, resulting in a differential band ∼500 bp in size between female and male gametophytes of Rongfu strain of S. japonica. According to the SCAR (sequence‐characterized amplified regions) strategies, one pair of primers, P51, was designed on the basis of the sequence of this band that was only present in female gametophytes. A SCAR marker, designated FRML‐494 (494‐bp Female‐Related Marker of S. japonica, GenBank accession no. EU931619), was developed successfully by PCR amplification using the designed P51 primer pair. The SCAR marker was verified to be present only in female gametophytes of another variety 901 of this kelp that was a hybrid between S. japonica as paternal and S. longissima (Miyabe) C. E. Lane, C. Mayes, Druehl et G. W. Saunders (=Laminaria longissima Miyabe) as maternal, suggesting that the FRML‐494 marker was specifically related to female gametophytes of the genus. This marker is the first molecular tool reported for sex identification in kelps. This study was beneficial for identifying gametophyte gender during vegetative growth and for judging whether the monogenetic sporophytes came from exclusive male or female gametophytes, as well as for further research on sex determination at the molecular level in kelps.
CONSTRUCTION AND CHARACTERIZATION OF A TENTATIVE AMPLIFIED FRAGMENT LENGTH POLYMORPHISM–SIMPLE SEQUENCE REPEAT LINKAGE MAP OF LAMINARIA (LAMINARIALES, PHAEOPHYTA)1
Authors: Yang Guanpin , Sun Ying , Shi Yuanyuan , Zhang Linan , Guo Shanshan , Li Bingjun , Li Xiaojie , Li Zhiling , Cong Yizhou , Zhao Yushan , Wang Wenquan
Published: August 2009

A tentative amplified fragment length polymorphism–simple sequence repeat (AFLP–SSR) linkage map of Laminaria was constructed using a haploid population of 40 gametophyte clones isolated from an individual of Dongfang No. 2, the first commercially cultured hybrid of a female gametophyte clone of L. japonica Aresch. [=Saccharina japonica (Aresch.) C. E. Lane, C. Mayes et G. W. Saunders] and a male one of L. longissima Miyabe [=Saccharina longissima (Miyabe) C. E. Lane, C. Mayes et G. W. Saunders]. To the map, 263 markers (255 AFLP, seven SSR, and the gametophyte sex) were assigned. The map consisted of 25 linkage groups (LGs) with ≥ four markers, five triplets, and 15 doublets, which is 1,629.0 centiMorgans (cM) in length, covering 66% of Laminaria genome. The maximum space between loci is 24.63 cM. A putative sex‐determining region was identified in LG2, which was characterized by a dense marker distribution around the gametophyte sex locus. The linkage map itself and the methodology associated with its construction will facilitate the genetic study and further trials of the linkage map construction of Laminaria.
The efficacy of individual‐donation and minipool testing to detect low‐level hepatitis B virus DNA in Taiwan
Authors: Yang Meng‐Hua , Li Lei , Hung Ying‐Shen , Hung Cheng‐Shen , Allain Jean‐Pierre , Lin Kuo‐Sin , Tsai Su‐Jen Lin
Published: August 2009

BACKGROUND: Financial constraints are the main concern in implementing nucleic acid testing (NAT) as routine blood screening in Taiwan. The PROCLEIX ULTRIO assay (Ultrio) on the TIGRIS System (Novartis Diagnostics) was evaluated for its operational performance both for individual‐donation testing (IDT) and in minipools of 4 (MP4) to develop a feasible solution.

STUDY DESIGN AND METHODS: Analytical sensitivity was determined by testing WHO international standards. We tested 10,290 blood donors, 4210 in IDT and 6080 in MP4. Potential hepatitis B virus (HBV) yield donors (hepatitis B surface antigen [HBsAg] negative/NAT reactive) were evaluated for up to 9 months' follow‐up. Discordant results between the Ultrio assay and the HBsAg tests were further analyzed by HBV antibody serology, alternative NATs, HBV DNA quantification, and sequencing.

RESULTS: The 95% limits of detection in IU/mL (95% confidence interval) were as follows: human immunodeficiency virus Type 1 (HIV‐1), 18 (12‐34); hepatitis C virus (HCV), 4.4 (2.8‐8.9); and HBV, 6.3 (4.4‐11). The retest rates were 0.55% for IDT and 0.33% for MP4. No HIV or HCV yield cases were found, while there were 12 potential HBV yield cases, nine from IDT and three from MP4 testing. Eleven of them were successfully genotyped as B2. Ten of them returned for follow‐up and mostly were determined as occult HBV infection (OBI). The IDT yield rate of 9 in 4210 (0.21%) was fourfold greater than the MP4 yield rate of 3 in 6080 (0.05%; p < 0.05).

CONCLUSION: The higher yield rate for IDT versus MP4 demonstrates the benefit to implement a more sensitive NAT strategy in regions having significant OBI carriers such as Taiwan.
Number of Accidents or Number of Claims? An Approach with Zero‐Inflated Poisson Models for Panel Data
Authors: Boucher Jean‐Philippe , Denuit Michel , Guillen Montserrat
Published: August 2009

Abstract

The hunger for bonus is a well‐known phenomenon in insurance, meaning that the insured does not report all of his accidents to save bonus on his next year's premium. In this article, we assume that the number of accidents is based on a Poisson distribution but that the number of claims is generated by censorship of this Poisson distribution. Then, we present new models for panel count data based on the zero‐inflated Poisson distribution. From the claims distributions, we propose an approximation of the accident distribution, which can provide insight into the behavior of insureds. A numerical illustration based on the reported claims of a Spanish insurance company is included to support this discussion.
Increasing Convergence Between U.S. and International Securitized Property Markets: Evidence Based on Cointegration Tests
Authors: Yunus Nafeesa
Published: August 2009

This article examines the degree of interdependence among the securitized property markets of six major countries and the United States. Long‐run results indicate that, over a period beginning January 1990 and ending August 2007, the property markets of Australia, Hong Kong, Japan, the United Kingdom and the United States are tied together, implying that from the perspective of the U.S. investor the markets of the Netherlands and France provide the greater diversification benefits. Further, the United States and Japan are found to be the sources of the common trends, suggesting that the two larger property markets lead the five (cointegrated) markets toward the long‐run equilibrium relationships.
The Liquidity of Property Shares: An International Comparison
Authors: Brounen Dirk , Eichholtz Piet , Ling David
Published: August 2009

This article investigates the magnitude and determinates of share liquidity over the 1990–2007 period in the world's four largest securitized real estate markets: the United States, the United Kingdom, Continental Europe and Australia. We document a significant and consistent role for market capitalization, nonretail share ownership and dividend yield as drivers of liquidity across markets. We also document significant differences in liquidity across countries and between property and nonproperty companies. Also striking is the lack of correlation among our three measures of liquidity across property firms and time. This supports the notion that share price liquidity is multifaceted and therefore reliance on any one measure of liquidity in empirical work may produce misleading conclusions. Although we find some evidence of a connection between liquidity and firm value, it is less conclusive than prior studies.
REIT Capital Budgeting and Equity Marginal q
Authors: Ambrose Brent W. , Lee Dong Wook
Published: August 2009

Equity marginal q is the change in the market value of a company's equity in response to a one‐unit unexpected change in its asset base. Hence, it is a profitability index that evaluates a firm's capital budgeting decisions at the margin. We estimate the equity marginal q for real estate–managing public corporations, namely, real estate investment trusts (REITs), in an attempt to understand how the various costs and benefits of being a public corporation play a role in managing this important asset class. Using the universe of equity REITs for the period from 1993 to 2005, we find that REITs with greater idiosyncratic volatility, higher stock turnover and smaller bid‐ask spread have a higher equity marginal q. In addition, both the holdings of institutional investors and their investment horizons are respectively positively related to equity marginal q. With these firm characteristics taken into account, firm size is found to be negatively related to equity marginal q. Our findings are economically important as well, because the equity marginal q ratio alone accounts for approximately one‐third of the total REIT shareholder wealth change during the study period.
REIT Auditor Fees and Financial Market Transparency
Authors: Danielsen Bartley R. , Harrison David M. , Van Ness Robert A. , Warr Richard S.
Published: August 2009

This article examines the relationship between overinvestment in audit services, abnormal nonaudit fees paid to the auditor and market‐based measures of firm transparency. Because real estate investment trusts (REITs) must distribute 90% of their earnings as dividends, many are repeat participants in the seasoned equity market. Thus, REITs have unusually strong incentives to strive for security market transparency. We find that the capital markets reward REITs that overinvest in audit services with better liquidity as measured by bid‐ask spreads. However, firms with abnormally high nonaudit expenditures appear to be penalized with wider spreads, consistent with the notion that such fees may compromise auditor independence.
Long‐Term Performance of the Attain Model 4193 Left Ventricular Lead
Authors: JOHNSON W. BEN , ABRAHAM WILLIAM T. , YOUNG JAMES B. , WHEELAN KEVIN , SMITH ANDREW L. , CHANG YANPING , BRINKMAN PAULA ,   For the InSync Registry Investigators
Published: August 2009

Background: Cardiac resynchronization therapy (CRT) has proven to be a valuable therapy addition for patients with drug‐refractory heart failure and a ventricular conduction delay. Delivery of CRT is dependent upon the successful implantation and chronic performance of a left ventricular (LV) pacing lead. This study assessed the long‐term electrical performance and safety of a steroid‐eluting, transvenous, over‐the‐wire, cardiac vein pacing lead.

Methods: The Attain Model 4193 LV lead (Medtronic, Inc, Minneapolis MN, USA) was successfully implanted in 1,070 patients with 286 patients completing 3 years of follow‐up. Clinical data were collected at pre‐implant, implant, and at 6‐month intervals for 3 years.

Results: Over 3 years, the mean chronic pacing threshold ranged from 1.9 V to 2.1 V, the mean R‐wave sensing amplitudes ranged between 13.6 mV and 15.0 mV, and the mean pacing impedance ranged between 562 ohms and 590 ohms. Additionally, the observed freedom from first post‐implant LV‐lead‐related complications was 90.4%. Of 1,070 total patients, 82 experienced 89 LV‐lead‐related adverse events requiring invasive interventions or resulting in the termination of the CRT therapy. The LV lead was repositioned in 31 patients, replaced in 21 patients, and explanted/capped in four patients. There were no deaths related to the LV lead during implantation or during the follow‐up period.

Conclusions: The data suggest that the 4193 LV lead is safe and effective over time. The LV lead electrical measurements remained stable through follow‐up, demonstrating reliable long‐term performance within the recommended value range at 36 months and had an acceptable complication rate.
Long‐term Stability of Endocardial Left Ventricular Pacing Leads Placed via the Coronary Sinus
Authors: LIN GRACE , ANAVEKAR NANDAN S. , WEBSTER TRACY L. , REA ROBERT F. , HAYES DAVID L. , BRADY PETER A.
Published: August 2009

Background: Left ventricular endocardial pacing leads placed via the coronary sinus (CS) are increasingly implanted to achieve cardiac resynchronization therapy (CRT); however, the long‐term stability of these leads is unknown. We sought to determine the implant success and long‐term stability of CS leads in our single center experience.

Methods: All consecutive patients who underwent CRT via implantation of the CS lead between January 1999 and December 2005 were included. Pacing thresholds at implant and during long‐term follow‐up were reviewed and the rate of acute (within 24 hours of implant) and chronic (>24 hours) lead failure was determined.

Results: A total of 512 patients (mean age 68 ± 12 years; 409 [80%] male) underwent CRT device implantation and were included. The CS lead implantation was successful on the initial implantation in 487 patients (95%) and subsequently successful in six patients (24%) in whom initial attempts were unsuccessful. Acute lead failure occurred in 25 patients (5.1%) and was most commonly due to persistent extra‐cardiac stimulation. The rate of chronic lead failure was 4% in the first year and remained stable during long‐term follow‐up. The CS lead pacing thresholds remained stable with only minimal increase (1.42 ± 0.85 V/0.42 ± 0.25 ms vs 1.51 ± 1.05 V/0.47 ± 0.29 ms; P = 0.04).

Conclusions: Placement of a left ventricular pacing lead via the CS is feasible and safe in the vast majority of patients. Once placed, the CS leads remain stable with excellent pacing thresholds over the longer term.
Use of Radiofrequency Perforation for Lead Placement in Biventricular or Conventional Endocardial Pacing after Mustard or Senning Operations for D‐Transposition of the Great Arteries
Authors: CHAKRABARTI SANTABHANU , SZANTHO GERGELY , TURNER MARK S , STUART GRAHAM , MARTIN ROBIN P
Published: August 2009

Background: Endocardial pacemaker lead placement can be challenging after Mustard and Senning operations for transposition of the great arteries (D‐TGA), if there is atresia of the systemic venous pathways and because the coronary sinus cannot be used for cardiac resynchronization therapy. Radiofrequency (RF)‐assisted perforation techniques have been used in congenital heart disease but have not been reported for use in pacemaker implantation.

Methods and Results: We describe RF perforation of an atretic superior systemic venous pathway and systemic venous baffles in three patients after Senning and Mustard operations to implant endocardial pacing systems to achieve conventional or biventricular pacing.

Conclusions: RF‐energy‐assisted perforation is feasible and effective tool to facilitate endocardial lead placement during dual‐chamber and biventricular pacemaker implantation in patients with Mustard or Senning operations for D‐TGA.
Management Strategies When Implanted Cardioverter Defibrillator Leads Fail: Survey Findings
Authors: XU WENJIE , MOORE HANS J. , KARASIK PAMELA E. , FRANZ MICHAEL R. , SINGH STEVE N. , FLETCHER ROSS D.
Published: August 2009

Background:

Defibrillator implanters have adopted different approaches to managing failures of multicomponent implanted cardioverter defibrillator (ICD) leads. Although recent publications identified single‐component failures as common mechanisms of failure, there are no published data regarding how best to manage these failures.

Methods:

An internet‐based survey was conducted to identify current management strategies. Questions were asked regarding isolated failure of a high‐voltage coil or of a pace/sense electrode, in order to identify the frequency of various techniques to correct these failures.

Results:

A worldwide query collected strategies from 376 physicians identifying themselves as ICD‐implanting physicians. Replies came from 28 countries, with the USA accounting for 83.2%. The survey was completed by 85.6% of respondents. Implant experience was >10 years for 61.1%, 3–10 years for 29.1%, and <3 years for 10.4%. When the right ventricular coil failed, 52% abandoned and 48% explanted the failed lead. In superior vena cava coil failure, 61.2% chose to simply exclude this coil, using the other intact lead components. For pace/sense defects, 53.1% chose to implant a new pace/sense lead or switch sensing electrodes, using the intact lead components. Medical literature (76.1%), personal experience (67.6%), and professional guidelines (63.7%) were strong decision‐making influences.

Conclusions:

(1) Management decisions for single‐component failures of ICD leads are complex; (2) Significant differences in management strategy exist among physicians; (3) Medical literature and professional guidelines are strong influences for these decisions; (4) A lead failure registry could help identify reasons for such differences and help guide management.
Strength Duration Curve for Left Ventricular Epicardial Stimulation in Patients Undergoing Cardiac Resynchronization Therapy
Authors: DHAR SUNIL K. , HESTON KAREN J. , MADRAK LINDA J. , SHAH BINDI K. , DEGER FLORIN T. , GREENBERG RICHARD M.
Published: August 2009

Introduction:

The strength duration curve has been studied for right ventricular endocardial stimulation. There are differences between left ventricular epicardial and right ventricular endocardial stimulation due to different electrophysiologic properties and different electrode‐tissue interface. The strength duration curve for epicardial left ventricular stimulation has not been studied so far.

Methods:

One hundred and three patients were studied. The strength duration curves were determined for left ventricular epicardial and right ventricular endocardial stimulation. The studied points were chronaxie, rheobase, and voltage threshold at 0.5 ms. Left ventricular leads Guidant 4512, 4513, 4537, 4538 (unipolar, area 3.5 mm2; Guidant Corp., St. Paul, MN, USA), Medtronic 4193 (unipolar, area 5.8 mm2; Medtronic Inc., Minneapolis, MN, USA), Guidant 4518, 4542, 4543 (bipolar, area 4 mm2), St. Jude Medical (bipolar, area 4.8 mm2; St. Jude Medical, St. Paul, MN, USA), and Medtronic 4194 (bipolar, area 5.8 mm2) were studied.

Results:

The Guidant unipolar leads with a distal electrode area of 3.5 mm2 had a lower chronaxie than the other studied leads. The left ventricular epicardial and right ventricular endocardial chronaxie for 15 patients with Medtronic left ventricular leads 4194 or 4193 (5.8 mm2) and right ventricular leads 6947 (5.7 mm2) were 0.52 ± 0.36 ms and 0.62 ± 0.46 ms (P > 0.05).

Conclusion:

The left ventricular epicardial chronaxie depends on the lead. The left ventricular epicardial chronaxie is similar to the right ventricular endocardial chronaxie for leads with similar electrode stimulation area.
Sudden Cardiac Death in China
Authors: ZHANG SHU
Published: August 2009

Preliminary data suggest that sudden cardiac death (SCD) occur at a rate of 41.8/100,000 population in China, accounting for over 544,000 deaths annually. While about 70% of SCD are due to underlying coronary artery disease, several specific cardiomyopathies and hereditary heart diseases are endemic in China. Pharmacological treatment is the main treatment strategy, and both community resuscitation and implantable cardioverter defibrillator therapy are limited by socioeconomic conditions. There is increasing use of catheter ablation for some ventricular arrhythmias. A national project has been started recently for SCD prevention.
The Association between T‐Wave Morphology and Life‐Threatening Ventricular Tachyarrhythmias in Patients with Congestive Heart Failure
Authors: LIN YEN‐HUNG , LIN LIAN‐YU , CHEN YING‐SHREN , HUANG HUI‐CHUN , LEE JEN‐KUANG , HO YI‐LWUN , LIAO LIN‐CHU , CHEN WEN‐JONE
Published: August 2009

Background:

Whether T‐wave morphology descriptors on the 12‐lead electrocardiogram (ECG) can predict the occurrence of life‐threatening ventricular arrhythmia in patients with advanced congestive heart failure is unclear.

Methods:

Standard 12‐lead ECGs were photoscanned and digitized for analysis in 27 heart failure patients with ventricular tachycardia/ventricular fibrillation (VT/VF; study group), as well as in 54 age‐ and sex‐matched heart failure patients without life‐threatening ventricular arrhythmia as a control group. Novel T‐wave morphology descriptors were compared.

Results:

The results showed that the temporal descriptor, the lead dispersion (LD; 426.5 ± 279.8 vs 189.0 ± 125.7, P < 0.001), was significantly higher in the study than in the control group. The other T‐wave morphology parameters, such as the T‐wave morphology dispersion (45.7 ± 20.1 vs 44.9 ± 18.6), the total cosine between QRS and T wave (TCRT; −0.4 ± 0.4 vs −0.5 ± 0.3), and the normalized T‐loop area (NTLA; 0.5 ± 0.1 vs 0.4 ± 0.1), were not significantly different between the two groups (all P value > 0.05). After an adjustment for other clinical variables, increased LD (odds ratio: 9.9, 95% confidence interval [CI]: 2.9–33.4, P < 0.001) or decreased NTLA (odds ratio: 0.4, 95% CI: 0.1–1.0, P =0.05) was associated with VT/VF.

Conclusion:

The novel T‐wave morphology analysis may help in identifying heart failure patients at high risk for VT/VF.
The Effect of Acute Psychological Stress on QT Dispersion in Patients with Coronary Artery Disease
Authors: HASSAN MUSTAFA , MELA APRIL , LI QIN , BRUMBACK BABETTE , FILLINGIM ROGER B. , CONTI JAMIE B. , SHEPS DAVID S.
Published: August 2009

Background: An acute psychological stress can precipitate ventricular arrhythmias and sudden cardiac death in patients with coronary artery disease (CAD). However, the physiologic mechanisms by which these effects occur are not entirely clear. Mental stress‐induced myocardial ischemia occurs in a significant percentage of the CAD population. It is unknown if the proarrhythmic effects of psychological stress are mediated through the development of myocardial ischemia.

Objectives: To examine the effects of psychological stress on QT dispersion (QTd) among CAD patients and whether these effects are mediated via the development of myocardial ischemia.

Methods: Psychological stress was induced using a public speaking task. Twelve‐lead electrocardiograms (ECG) were recorded at rest, during mental stress, and during recovery. QTd was calculated as the difference between the longest and the shortest QT interval in the 12‐lead ECG. Rest‐stress myocardial perfusion imaging was also performed to detect mental stress‐induced myocardial ischemia.

Results: Mental stress induced a significant increase in QTd compared to the resting condition (P < 0.001). This effect persisted beyond the first 10 minutes of recovery (P < 0.001). QTd was significantly associated with the development of mental stress ischemia with ischemic patients having significantly higher QTd during mental stress than nonischemic patients (P = 0.006). This finding remained significant after controlling for possible confounding factors (P = 0.01).

Conclusion: An acute psychological stress induces a significant increase in QTd, which persists for more than 10 minutes after the cessation of the stressor. This effect seems to be, at least partially, mediated by the development of mental stress‐induced myocardial ischemia.
Carotid Sinus Hypersensitivity is Common in Patients Presenting with Hip Fracture and Unexplained Falls
Authors: SACHPEKIDIS VASILEIOS , VOGIATZIS IOANNIS , DADOUS GEORGE , KANONIDIS IOANNIS , PAPADOPOULOS CONSTANTINOS , SAKADAMIS GEORGE
Published: August 2009

Background:

We tried to determine the prevalence of carotid sinus hypersensitivity (CSH) in patients with hip fractures with and without a clear history of an accidental fall.

Methods:

We studied 51 patients hospitalized for a hip fracture and 51 matched controls from our outpatients department. All patients were subjected to a carotid sinus massage in the supine and upright position
. Patients were categorized in accidental (Group A) and unexplained (Group B) fallers.

Results:

Six of 33 (18.2%) patients in Group A and 12 of 18 (66.7%) patients in Group B (P < 0.001) had a positive response to the carotid sinus massage. Nine controls (17.6%) also demonstrated CSH. Patients in Group B were older (A: 75.5 ± 8.5 years vs B: 80.1 ± 5.9 years, P =0.029) and were more likely to have a history of unexplained falls or syncope in the past (A: 0% vs B: 66.7%, P < 0.0001) than individuals in group A. Vasodepressor/mixed forms accounted for the majority of CSH responses in Group B (75%). When compared with the control group, CSH was still more common in Group B (B: 66.7% vs control: 17.6%, P < 0.0001) but not in Group A (A: 18.2% vs control: 17.6%, P =1.000).

Conclusions:

The prevalence of CSH is increased in elderly patients with hip fractures, only in those who present with an unexplained fall and report a history of syncope or unexplained falls in the past. The vasodepressor/mixed forms account for the majority of CSH responses in the group of unexplained fallers.
Modern Pacemakers: Hope or Hype?
Authors: DAS MITHILESH K. , DANDAMUDI GOPI , STEINER HILLEL A.
Published: August 2009

In recent years, the role of implantable pacing devices has expanded beyond the arrhythmia horizon and contemporary pacemakers’ attempt to meet the physiological needs of patients. Modern pacemakers' functions include various modes of dual‐chamber pacing, rate‐response algorithms with dual sensors for optimum physiological response, cardiac resynchronization therapy (CRT), arrhythmia‐prevention algorithms, antitachycardia pacing, and hemodynamic monitoring. The automaticity features of pacemakers enable continuous or intermittent monitoring of various pacemaker parameters including battery voltage, pacing impedance, sensing levels, pacing thresholds, and daily activity log. Modern pacemakers offer “physiological pacing” algorithms that minimize ventricular pacing and reduce the incidence of atrial fibrillation significantly. Ventricular pacing in patients with intact atrioventricular (AV) conduction or intermittent advanced AV block should be minimized with a hope to reduce heart failure hospitalization and mortality. A reduction in all‐cause mortality due to physiological pacing, except for the CRT, has yet to be demonstrated in a randomized trial. Overall, modern pacemakers have acceptable performances to fulfill the clinical needs and have a reasonable safety margin. Promising new technologies are currently under development and offer hope to patients who may one day derive both symptomatic and mortality benefit from these devices.
Alternation of Right Bundle Branch Block with Beats Showing Normal Conduction and with a Less Complete Right Bundle Branch Block Pattern
Authors: VERECKEI ANDRÁS , TENCZER JÓZSEF , HICKMAN MICHAEL
Published: August 2009

We report the case of an 80‐year‐old man with a preexistent right bundle branch block (RBBB) who underwent dobutamine stress echocardiography. As the sinus cycle length gradually decreased during the stress test, he first developed a 2:1 RBBB pattern alternating with beats showing normal conduction and then an alternating 2:1 less complete and more complete RBBB pattern. An elucidation of the potential mechanism of the latter very rare phenomenon is provided.