bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring the Impact of Promotions on Brand Switching When Consumers Are Forward Looking
Authors: Sun Baohong , Neslin Scott A. , Srinivasan Kannan
Published: November 2003

Logit choice models have been used extensively to study promotion response. This article examines whether brand-switching elasticities derived from these models are overestimated as a result of rational consumer adjustment of purchase timing to coincide with promotion schedules and whether a dynamic structural model can address this bias. Using simulated data, the authors first show that if the structural model is correct, brand-switching elasticities are overestimated by stand-alone logit models. A nested logit model improves the estimates, but not completely. Second, the authors estimate the models on real data. The results indicate that the structural model fits better and produces sensible coefficient estimates. The authors then observe the same pattern in switching elasticities as they do in the simulation. Third, the authors predict sales assuming a 50% increase in promotion frequency. The reduced-form models predict much higher sales levels than does the dynamic structural model. The authors conclude that reduced-form model estimates of brand-switching elasticities can be overstated and that a dynamic structural model is best for addressing the problem. Reduced-form models that include incidence can partially, though not completely, address the issue. The authors discuss the implications for researchers and managers.
Measuring Preferences for Really New Products
Authors: Hoeffler Steve
Published: November 2003

The goal of this research is to improve preference measurement for really new products. An initial assumption validated in the first study is that consumers have greater uncertainty when estimating the usefulness of really new products than they have with incremental new products. Consumers cope with this uncertainty by using certain inferential techniques that are not well captured by standard preference measurement techniques, such as conjoint. This research examines techniques for incorporating both mental simulation and analogies into an existing preference measurement technique and shows that some methods enhance and other methods hinder predictive accuracy.
Why Do Consumers Stop Viewing Television Commercials? Two Experiments on the Influence of Moment-to-Moment Entertainment and Information Value
Authors: Elpers Josephine L.C.M. Woltman , Wedel Michel , Pieters Rik G.M.
Published: November 2003

This research demonstrates the positive effects of moment-to-moment entertainment and the negative effects of moment-to-moment information value on consumers' likelihood to continue watching during a television commercial. A notable finding is that both the entertainment and the information value have a strong multiplicative effect on the probability to stop viewing.
Is 75% of the Sales Promotion Bump Due to Brand Switching? No, Only 33% Is
Authors: Van Heerde Harald J. , Gupta Sachin , Wittink Dick R.
Published: November 2003

Several researchers have decomposed sales promotion elasticities based on household scanner-panel data. A key result is that the majority of the sales promotion elasticity, approximately 74% on average, is attributed to secondary demand effects (brand switching) and the remainder is attributed to primary demand effects (timing acceleration and quantity increases). The authors demonstrate that this result does not imply that if a brand gains 100 units in sales during a promotion, the other brands in the category lose 74 units. The authors offer a complementary decomposition measure based on unit sales. The measure shows the ratio of the current cross-brand unit sales loss to the current own-brand unit sales gain during promotion; the authors report empirical results for this measure. They also derive analytical expressions that transform the elasticity decomposition into a decomposition of unit sales effects. These expressions show the nature of the difference between the two decompositions. To gain insight into the magnitude of the difference, the authors apply these expressions to previously reported elasticity decomposition results and find that approximately 33% of the unit sales increase is attributable to losses incurred by other brands in the same category.
Reno-vascular hypertension treated with percutaneous transluminal angioplasty
Authors: Dong Zong Jun , Zhang Jian , Yu Heng Xi , Li Jian Xin
Published: November 2003

Eighty seven cases of reno-vascular hypertension were treated with percutaneous transluminal angioplasty (PTA) between October 1981 and October 1997. Athrosclerosis was the etiology of renal artery lesions in 14 cases (16.1%), arthritis in 65 cases (74.7%), and fibromuscular dysplasia (FMD) in 8 cases (9.2%). There were 116 renal arteries suffered. Unilateral disease was in 48 cases, bilateral was in 39 cases. Average length of stenostic segment was 9.0 ± 5.75 mm (mean ± SD) before PTA, the wide was 1.81 ± 0.99 mm, after PTA, the average wide was 3.95 ± 1.29 mm. The systolic blood pressure was 198 ± 34 mmHg, diastolic was 124 ± 23 mmHg before treatment. At the follow-up period, 51 (1–168) months, the systolic blood pressure was 144 ± 15 mmHg, and diastolic pressure was 93 ± 13 mmHg. The morbidity rate in this series was 8% (one false aneurysm at the puncture site, one renal artery dissection, two renal artery thrombosed, and three bleeding at the puncture site). There was no mortality. The cure-improve rate in athrosclerosis cases was 57.1%, in arteritis cases was 81.6%, FMD was 87.5%. The conclusion was PTA should be considered as the first choice for the treatment of renovascular hypertension, especially for the arthritis patients.
Stress drops and radiated energies of aftershocks of the 1994 Northridge, California, earthquake
Authors: Mori Jim , Abercrombie Rachel E. , Kanamori Hiroo
Published: November 2003

We study stress levels and radiated energy to infer the rupture characteristics and scaling relationships of aftershocks and other southern California earthquakes. We use empirical Green functions to obtain source time functions for 47 of the larger (M ≥ 4.0) aftershocks of the 1994 Northridge, California earthquake (M6.7). We estimate static and dynamic stress drops from the source time functions and compare them to well‐calibrated estimates of the radiated energy. Our measurements of radiated energy are relatively low compared to the static stress drops, indicating that the static and dynamic stress drops are of similar magnitude. This is confirmed by our direct estimates of the dynamic stress drops. Combining our results for the Northridge aftershocks with data from other southern California earthquakes appears to show an increase in the ratio of radiated energy to moment, with increasing moment. There is no corresponding increase in the static stress drop. This systematic change in earthquake scaling from smaller to larger (M3 to M7) earthquakes suggests differences in rupture properties that may be attributed to differences of dynamic friction or stress levels on the faults.
Temperature‐dependent streaming potentials: 1. Theory
Authors: Reppert Philip M. , Morgan Frank Dale
Published: November 2003

The variation of streaming potentials (voltage/pressure cross‐coupling coefficient) with temperature is examined with particular emphasis on the effect of temperature on zeta potentials. The variation of streaming potential with temperature cannot be explained solely by the known temperature dependence of water viscosity, permittivity, and conductivity; the change of zeta potential with temperature must also be included. Many previous experimental studies show that the magnitude of the zeta potential increases with temperature. It was found in this study that the increase is controlled primarily by the surface charge density. These changes are influenced by the absorption properties of the surface and thus the surface charge, which in turn affects the Stern layer charge and properties of the electrical double layer. It is found that the slope of the temperature versus zeta potential curve is controlled by the change in enthalpy of the surface reactions. It was also found that viscosity is the most dominant term in the coupling coefficient, but changes in the conductivity model used to determine zeta potentials can also affect streaming potential coupling coefficient results. For the cases studied, the temperature‐dependent zeta potential is determined by the temperature‐dependent behavior of the Debye‐Hückel parameter, 4%; the diffuse layer of electrical double layer (EDL), 6%; and the surface charge, 90%. The Revil and Glover model was able to account for much of the change in the surface charge density caused by changes in temperature.
Low‐frequency tremors, intraslab and interplate earthquakes in Southwest Japan—from a viewpoint of slab dehydration
Authors: Seno Tetsuzo , Yamasaki Tadashi
Published: November 2003

Low‐frequency tremors (LFT) recently found in the Southwest Japan fore‐arc likely occur due to hydro‐fracturing from fluids leaving the dehydrating Philippine Sea slab. However, there are some places without such LFT; they are N. Izu‐Kanto, E. Shikoku, and S. Kyushu. These are the places where island‐arc type crust is subducting. We propose that dehydration of the subducted crust does not occur beneath these regions, because it is composed mainly of tonalite, lacking the quantity of hydrous minerals seen in normal subducting oceanic crust. We show that almost no earthquake occurs within the subducted crust in such regions, consistent with dehydration embrittlement hypothesis for intraslab seismicity. The lack of dehydration from the crust would also affect the mode of occurrence of interplate earthquakes, because pore fluid pressure is more difficult to rise at the thrust zone. This might be reflected in the irregular occurrence of great earthquakes in these regions.
Solar cycle modulation of the seasonal linkage of the North Atlantic Oscillation (NAO)
Authors: Ogi Masayo , Yamazaki Koji , Tachibana Yoshihiro
Published: November 2003

The influence of the winter NAO on the high‐latitude summer climate is examined by separating the years according to the 11‐year solar cycle. During the solar maximum years, the winter NAO has a significant relation with the spring‐summer climate, while the winter‐to‐summer linkage is very weak during the solar minimum years. During the solar maximum years, the winter NAO affects spring snow cover over the Eurasian continent and sea ice over the Barents Sea. In summer, the NAO signal shows a strong annular‐like structure only during solar maximum years. The results suggest that the influence of the winter NAO on the summer climate is modulated by the solar cycle through the surface cryospheric processes.
Groundwater level changes in a deep well in response to a magma intrusion event on Kilauea Volcano, Hawai'i
Authors: Hurwitz Shaul , Johnston Malcolm J. S.
Published: November 2003

On May 21, 2001, an abrupt inflation of Kilauea Volcano's summit induced a rapid and large increase in compressional strain, with a maximum of 2 μstrain recorded by a borehole dilatometer. Water level (pressure) simultaneously dropped by 6 cm. This mode of water level change (drop) is in contrast to that expected for compressional strain from poroelastic theory, and therefore it is proposed that the stress applied by the intrusion has caused opening of fractures or interflows that drained water out of the well. Upon relaxation of the stress recorded by the dilatometer, water levels have recovered at a similar rate. The proposed model has implications for the analysis of ground surface deformation and for mechanisms that trigger phreatomagmatic eruptions.
Modeling decadal variability of the Baltic Sea: 2. Role of freshwater inflow and large‐scale atmospheric circulation for salinity
Authors: Meier H. E. Markus , Kauker Frank
Published: November 2003

Hindcast simulations for the period 1902–1998 have been performed using a three‐dimensional coupled ice‐ocean model for the Baltic Sea. Daily sea level observations in Kattegat, monthly basin‐wide discharge data, and reconstructed atmospheric surface data have been used to force the Baltic Sea model. The reconstruction utilizes a statistical model to calculate daily sea level pressure and monthly surface air temperature, dew point temperature, precipitation, and cloud cover fields. Sensitivity experiments have been performed to explore the impact of the freshwater and saltwater inflow variability on the salinity of the Baltic Sea. The decadal variability of the average salinity is explained partly by decadal volume variations of the accumulated freshwater inflow from river runoff and net precipitation and partly by decadal variations of the large‐scale sea level pressure over Scandinavia. During the last century two exceptionally long stagnation periods are found, the 1920s to 1930s and the 1980s to 1990s. During these periods, precipitation, runoff, and westerly winds were stronger, and salt transports into the Baltic were smaller than normal. As the response timescale on freshwater forcing of the Baltic Sea is about 35 years, seasonal and year‐to‐year changes of the freshwater inflow are too short to affect the average salinity significantly. We found that the impact of river regulation, which changes the discharge seasonality, is negligible.
Interannual volume variability in the tropical Pacific
Authors: Holland Christina L. , Mitchum Gary T.
Published: November 2003

The question of whether or not the volume of the tropical Pacific changes over the course of an El Niño event has potentially important consequences for our understanding of the dynamical mechanisms responsible for El Niño‐Southern Oscillation (ENSO) events. In this study, we examine the volume variability of the tropical Pacific, defined as the areal integral of the sea surface height variability, using TOPEX/Poseidon altimetric sea surface heights and the output of a numerical model. We find that volume gradually builds up in the tropical Pacific prior to a typical ENSO event and rapidly decreases during the event due to volume flux out of the tropics. However, our results confirm the findings of previous studies showing that volume change over the entire tropical Pacific does occur on ENSO timescales, but that this variability is small when compared to the volume redistribution within the tropical Pacific. In particular, there is a large volume flux into and out of the equatorial waveguide. Furthermore, we find that the volume variability of the tropical Pacific during ENSO can be almost entirely accounted for by variations in the temperature field.
Massive Solar Storms Inflict Little Damage on Earth
Authors: Simpson Sarah
Published: November 2003

The face of the Sun had been peaceful and blemish‐free for much of 2003. But space weather forecasters knew trouble was brewing on 24 October when Jupiter‐sized sunspot 486 rotated into full view. Combined with two other unusually large spots, number 486 would kick up the most intense solar activity in 30 years according to several NOAA and NASA officials who were interviewed during the accompanying flurry of media coverage.
N‐Salicyloyltryptamine, a new anticonvulsant drug, acts on voltage‐dependent Na+, Ca2+, and K+ ion channels
Authors: Araújo Demétrius Antonio Machado , Mafra Roberta Amaral , Rodrigues Andréia Laura Prates , Miguel‐Silva Válter , Beirão Paulo Sérgio Lacerda , De Almeida Reinaldo Nóbrega , Quintans Lucindo , Souza Maria Fátima Vanderlei de , Cruz Jader Santos
Published: November 2003

The aim of this work was to study the effects of N‐salicyloyltryptamine (STP), a novel anticonvulsant agent, on voltage‐gated ion channels in GH3 cells.

In this study, we show that STP at 17 μM inhibited up to 59.2±10.4% of the Ito and 73.1±8.56% of the IKD K+ currents in GH3 cells. Moreover, the inhibitory activity of the drug STP on K+ currents was dose‐dependent (IC50=34.6±8.14 μM for Ito) and partially reversible after washing off.

Repeated stimulation at 1 Hz (STP at 17 μM) led to the total disappearance of Ito current, and an enhancement of IKD.

In the cell‐attached configuration, application of STP to the bath increased the open probability of large‐conductance Ca2+‐activated K+ channels.

STP at 17 μM inhibited the L‐type Ca2+ current by 54.9±7.50% without any significant changes in the voltage dependence.

STP at 170 μM inhibited the TTX‐sensitive Na+ current by 22.1±2.41%. At a lower concentration (17 μM), no effect on INa was observed.

The pharmacological profile described here might contribute to the neuroprotective effect exerted by this compound in experimental ‘in vivo’ models.

British Journal of Pharmacology (2003) 140, 1331–1339. doi:10.1038/sj.bjp.0705471
Acute exposure of ceramide enhances cardiac contractile function in isolated ventricular myocytes
Authors: Relling David P , Hintz Kadon K , Ren Jun
Published: November 2003

The sphingolipid ceramide, a primary building block for all other sphingolipids, is associated with growth arrest, apoptosis, and lipotoxic dysfunction. Interestingly, ceramide may attenuate high glucose‐induced myocyte dysfunction, produce Ca2+ influx, and augment smooth muscle contraction. To determine the role of ceramide on cardiac excitation–contraction (E–C) coupling, electrically paced adult rat ventricular myocytes were acutely exposed to a cell‐permeable ceramide analog (10 pM–100 μM) and the following indices were determined: peak shortening (PS), time‐to‐P., time‐to‐90% relengthening, and the maximal velocity of shortening and relengthening (±dLdt). Intracellular Ca2+ properties were assessed using fura‐2AM fluorescent microscopy.

Our results revealed a concentration‐ and time‐dependent increase of PS in ventricular myocytes in response to ceramide associated with an increase in ±dLdt. The maximal increase in PS was ∼35% from control value and was maintained throughout the first 20 min of ceramide exposure. However, the ceramide‐induced increase in PS was not maintained once the exposure time was beyond 20 min. Acute exposure of ceramide significantly enhanced intracellular Ca2+ release, although at a much lower concentration range. The ceramide‐induced augmentation of PS was not significantly affected by inhibition of phosphatidylinositol (PI)‐3‐kinase, protein kinase C (PKC), ceramide‐activated protein phosphatase (CAPP), and nitric oxide (NO) synthase.

Our data suggest that ceramide acutely augments the contractile function of cardiac myocytes through an alternative mechanism(s) rather than PI‐3‐kinase, PKC, CAPP, or NO.

British Journal of Pharmacology (2003) 140, 1163–1168. doi:10.1038/sj.bjp.0705510
ATP and UTP responses of cultured rat aortic smooth muscle cells revisited: dominance of P2Y2 receptors
Authors: Kumari Rajendra , Goh Gareth , Ng Leong L , Boarder Michael R
Published: November 2003

It has previously been shown that ATP and UTP stimulate P2Y receptors in vascular smooth muscle cells (VSMCs), but the nature of these receptors, in particular the contribution of P2Y2 and P2Y4 subtypes, has not been firmly established. Here we undertake a further pharmacological analysis of [3H]inositol polyphosphate responses to nucleotides in cultured rat VSMCs.

ATP generated a response that was partial compared to UTP, as reported earlier.

In the presence of a creatine phosphokinase (CPK) system for regenerating nucleoside triphosphates, the response to ATP was increased, the response to UTP was unchanged, and the difference between UTP and ATP concentration–response curves disappeared. Chromatographic analysis showed that ATP was degraded slightly faster than UTP.

The response to UDP was always smaller than that to UTP, but with a shallow slope and a high potency component. In the presence of hexokinase (which prevents the accumulation of ATP/UTP from ADP/UDP), the maximum response to UDP was reduced and the high‐potency component of the curve was retained. By contrast, the response to ADP was weaker throughout in the presence of hexokinase.

ATPγS was an effective agonist with a similar EC50 to UTP, but with a lower maximum. ITP was a weak agonist compared with UTP.

Suramin was an effective antagonist of the response to UTP (pA2=4.48), but not when ATP was the agonist. However, suramin was an effective antagonist (pA2=4.45) when stimulation with ATP was in the presence of the CPK regenerating system.

Taken together with the results of others, these findings indicate that the response of cultured rat VSMCs to UTP and to ATP is predominantly at the P2Y2 receptor, and that there is also a response to UDP at the P2Y6 receptor.

British Journal of Pharmacology (2003) 140, 1169–1176. doi:10.1038/sj.bjp.0705526
Rabbit aortic endothelial dysfunction by low‐density lipoprotein is attenuated by L‐arginine, L‐ascorbate and pyridoxine
Authors: Ji Yong , Han Yi , Diao Jianxin , Huang Yan , Chen Qi , Ferro Albert
Published: November 2003

We investigated the relative effectiveness of L‐arginine, L‐ascorbate and pyridoxine in preventing the impairment of endothelium‐mediated vasorelaxation induced by native low‐density lipoprotein (nLDL) from healthy subjects, oxidised LDL (oxLDL, formed by oxidation of nLDL) or nLDL from type II diabetic patients (dLDL).

Rabbit aortic rings were exposed to nLDL, dLDL or oxLDL (50–200 mg protein l−1), or corresponding vehicle, following which they were constricted with noradrenaline 10−6 M; concentration–relaxation curves were determined to acetylcholine (ACh), A23187, or sodium nitroprusside (NP), in the absence or presence of L‐arginine (10−5–10−3 M), L‐ascorbate (10−5–10−3 M) and pyridoxine (0.5–2.0 mM).

nLDL, dLDL and oxLDL all inhibited relaxant responses to ACh and A23187, but not to NP, in a concentration‐dependent manner (oxLDL>dLDL>nLDL).

In the presence of all LDL preparations, L‐arginine, L‐ascorbate or pyridoxine each improved ACh and A23187 responses, although none completely normalised endothelium‐dependent relaxations. The maximal effect of L‐arginine occurred at 10−4 M. The combination of L‐arginine 10−4 M, L‐ascorbate 10−5 M and pyridoxine 2.0 mM was equally effective as L‐arginine 10−4 M alone.

Our results confirm that nLDL, dLDL and oxLDL exert inhibitory effects on endothelium dependent, but not endothelium independent, relaxation of rabbit aorta. ACh and A23187 responses in the presence of any LDL species can be ameliorated by supplementation with L‐arginine, L‐ascorbate or pyridoxine, either singly or in combination, with no agent or combination proving superior to L‐arginine alone. Nevertheless, ACh and A23187 responses are not completely normalised with such supplements, suggesting that there also exists a component of LDL‐induced inhibition of endothelium‐mediated vasorelaxation that is independent of the nitric oxide system.

British Journal of Pharmacology (2003) 140, 1272–1282. doi:10.1038/sj.bjp.0705545
Hyper‐reactivity of cerebral arteries from ovariectomized rats: therapeutic benefit of tamoxifen
Authors: Thorin Eric , Pham‐Dang Mylan , Clement Robert , Mercier Isabelle , Calderone Angelino
Published: November 2003

An increased incidence of systemic hypertension has been documented in postmenopausal women and identified as an independent risk factor in the development of cerebrovascular stroke. The present study examined whether cerebrovascular reactivity was increased in the hypertensive ovariectomized rat, and explored the potential therapeutic benefit of the partial estrogen receptor agonist tamoxifen.

Female Sprague–Dawley rats were subjected to bilateral ovariectomy (OVX, n=16) or a sham operation (n=8). At 6‐week postsurgery, rats were anesthetized to assess ventricular contractility and blood pressure. In a second series of experiments, OVX rats (n=8) were given tamoxifen starting 3 weeks postsurgery, and continued for 3 weeks. At the end of each protocol, the middle cerebral artery was harvested and rings were mounted in wire‐myographs to measure isometric tension.

Systolic arterial pressure (SAP) was significantly increased (P<0.05) in the OVX rat (174±8 mmHg), as compared to sham (135±6 mmHg). The resting tension of isolated cerebral arteries from OVX rats (186±15 mg) was significantly elevated (P<0.05), as compared to sham (129±9 mg). Phenylephrine treatment did not elicit a constriction of cerebral arteries isolated from sham rats, whereas a potent response (P<0.05) was observed in OVX rats. Nitric oxide (NO) synthase inhibition with L‐NNA led to a limited contraction in sham rats (8±3% of Emax), whereas a significant (P<0.05) increase was observed in OVX rats (34±12% of Emax). Lastly, vascular sensitivity (pD2) to sodium nitroprusside was significantly increased (P<0.05) in OVX rats, as compared to sham.

Tamoxifen therapy normalized the resting tension of isolated cerebral arteries from OVX rats, abrogated phenylephrine‐mediated contraction, and modestly reduced SAP. By contrast, tamoxifen treatment of OVX rats did not attenuate L‐NNA‐mediated contractile response of cerebral arteries.

These data demonstrate that the cerebral artery isolated from the OVX rat was associated with an exaggerated vasoconstrictor response to phenylephrine, and altered NO‐dependent vascular reactivity. The administration of tamoxifen to OVX rats normalized cerebral artery reactivity to phenylephrine. These findings provide the impetus to examine the potential therapeutic benefit of the partial estrogen receptor agonist tamoxifen to reduce the incidence of cerebrovascular stroke in postmenopausal women.

British Journal of Pharmacology (2003) 140, 1187–1192. doi:10.1038/sj.bjp.0705547
T‐1032, a cyclic GMP phosphodiesterase‐5 inhibitor, acutely blocks physiologic insulin‐mediated muscle haemodynamic effects and glucose uptake in vivo
Authors: Mahajan Hema , Richards Stephen M , Rattigan Stephen , Clark Michael G
Published: November 2003

Cyclic GMP phosphodiesterase‐5 inhibitors have been shown to alter blood flow in specific tissues by potentiating local NO‐dependent vasodilatory mechanisms. Since the haemodynamic effects of physiologic insulin, particularly capillary recruitment, may be critical for muscle glucose uptake in vivo and are blocked by inhibitors of nitric oxide synthase, we have explored the acute effects of the specific cGMP phosphodiesterase‐5 inhibitor T‐1032 on physiologic insulin action in anaesthetized healthy rats in vivo.

Whole‐body glucose infusion (GIR), femoral blood flow (FBF), hind leg vascular resistance (VR), hind leg glucose uptake (HGU), 2‐deoxyglucose uptake into muscles of the lower leg (R′g), hind leg metabolism of infused 1‐methylxanthine (1‐MX), a measure of capillary recruitment, and muscle cGMP were determined. The experimental groups were T‐1032 (10 μg min−1 kg−1) infused for 1 h before and during a euglycaemic insulin clamp (3 mU min−1 kg−1 × 2 h), T‐1032 infused for 3 h with saline, T‐1032 during a 2 h clamp, T‐1032 with saline for 2 h, and a 2 h saline control.

Insulin increased GIR from zero to 13 mg min−1 kg−1, HGU from 0.1±0.01 to 0.43±0.05 μmol min−1, R′g and 1‐MX, marginally increased FBF, and had no effect on blood pressure or heart rate. T‐1032 alone had no effect on blood pressure, heart rate, FBF, VR, HGU, R′g or 1‐MX, but increased muscle cGMP. T‐1032 1 h before and during insulin completely blocked GIR (1 h), HGU (2 h), R′g (2 h), and 1‐MX (2 h). T‐1032 commenced with insulin had only partial blocking activity against insulin.

We conclude that T‐1032 is a potent acutely acting inhibitor of the muscle effects of physiologic insulin on capillary recruitment and glucose uptake in vivo. These, together with inhibition of whole‐body glucose infusion during insulin, may caution against the use of isoenzyme‐5‐specific cyclic GMP phosphodiesterase inhibitors as therapeutic agents.

British Journal of Pharmacology (2003) 140, 1283–1291. doi:10.1038/sj.bjp.0705548
Rho kinase inhibitors block activation of pancreatic stellate cells
Authors: Masamune Atsushi , Kikuta Kazuhiro , Satoh Mashiro , Satoh Kennichi , Shimosegawa Tooru
Published: November 2003

In response to pancreatic injury and in cell culture, pancreatic stellate cells (PSCs) are transformed (‘activated’) into highly proliferative myofibroblast‐like cells, which express α‐smooth muscle actin (α‐SMA), and produce type I collagen and other extracellular matrix components. There is accumulating evidence that activated PSCs play important roles in pancreatic fibrosis and inflammation.

The small GTP‐binding protein Rho has emerged as an important regulator of the actin cytoskeleton and cell morphology through the downstream effector Rho kinase (ROCK). But, the roles of Rho‐ROCK pathway in PSCs are unknown. Here, we examined the effects of (+)‐(R)‐trans‐4‐(1‐aminoethyl)‐N‐(4‐pyridyl) cyclohexanecarboxamide (Y‐27632) and HA‐1077 (fasudil), specific inhibitors of ROCK, on the activation of PSCs.

PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase P. The actin cytoskeleton was analyzed by phalloidin staining. Expression of RhoA and ROCK was examined by immunostaining and Western blotting. Effects of Y‐27632 and HA‐1077 on α‐SMA expression, platelet‐derived growth factor‐induced proliferation and chemotaxis, and collagen production were assessed.

Culture‐activated PSCs developed a well‐spread cell shape, with extended stress fiber formation. PSCs expressed RhoA, ROCK‐1, and ROCK‐2.

Y‐27632 caused disassembly of stress fibers. Y‐27632 and HA‐1077 inhibited α‐SMA expression, proliferation, chemotaxis, and type I collagen production in culture‐activated PSCs.

In addition, Y‐27632 and HA‐1077 inhibited spontaneous activation of freshly isolated PSCs in culture on plastic.

These findings suggest a role of Rho‐ROCK pathway in the activation process of PSCs by regulating the actin cytoskeleton, and a potential application of Rho‐ROCK pathway inhibitors for the treatment of pancreatic inflammation and fibrosis.

British Journal of Pharmacology (2003) 140, 1292–1302. doi:10.1038/sj.bjp.0705551
Possible role of the protein kinase C/CPI‐17 pathway in the augmented contraction of human myometrium after gestation
Authors: Ozaki Hiroshi , Yasuda Katsuhiko , Kim Yoon‐Sun , Egawa Makoto , Kanzaki Hideharu , Nakazawa Hiroshi , Hori Masatoshi , Seto Minoru , Karaki Hideaki
Published: November 2003

Activation of protein kinase C (PKC) by phorbol 12,13‐dibutylate (PDBu, 1 μM) induced sustained contractions with no increase in [Ca2+]i in nonpregnant and pregnant human myometria. The contractile effects of PDBu in pregnant myometrium were much greater than those in nonpregnant myometrium, and the contractions in pregnant myometrium were accompanied by an increase in myosin light chain (MLC) phosphorylation at Ser19.

The contraction induced by PDBu in pregnant myometrium was inhibited by the inhibitors of conventional PKC isoforms, bisindolylmaleimides and indolocarbazole, such as Go6976, Go6983, and Go6850 (1 μM). LY333531 (1 μM), a specific inhibitor of PKCβ, also inhibited the PDBu‐induced contraction in the pregnant myometrium.

In the pregnant myometrium permeabilized with α‐toxin, PDBu increased the contractions induced at fixed Ca2+ concentration (0.3 μM) both in nonpregnant and pregnant myometria, indicating Ca2+ sensitization of contractile elements.

Western immunoblot analysis indicated that pregnant myometrium contained PKC isozymes such as conventional PKC (α, β, γ), novel PKC (δ, ɛ, θ), and atypical PKC (ζ but not ι and λ). RT‐PCR and real‐time RT‐PCR analysis indicated that, among the conventional PKC, the levels of mRNA of β isoform in pregnant human myometrium were greater than those in nonpregnant myometrium.

CPI‐17 is a substrate for PKC, and the phosphorylated CPI‐17 is considered to inhibit myosin phosphatase. The levels of CPI‐17 mRNA and protein expression were also greater in the pregnant myometrium.

These results suggest that the PKC‐mediated contractile mechanism is augmented in human myometrium after gestation, and that this augmentation may be attributable to the increased activity of the β PKC isoform and CPI‐17.

British Journal of Pharmacology (2003) 140, 1303–1312. doi:10.1038/sj.bjp.0705552
Alkylglycerol opening of the blood–brain barrier to small and large fluorescence markers in normal and C6 glioma‐bearing rats and isolated rat brain capillaries
Authors: Erdlenbruch Bernhard , Alipour Mehrnaz , Fricker Gert , Miller David S , Kugler Wilfried , Eibl Hansjörg , Lakomek Max
Published: November 2003

The blood–brain barrier (BBB) represents the major impediment to successful delivery of therapeutic agents to target tissue within the central nervous system. Intracarotid alkylglycerols have been shown to increase the transfer of chemotherapeutics across the BBB.

We investigated the spatial distribution of intracarotid fluorescein sodium and intravenous lissamine‐rhodamine B200 (RB 200)–albumin in the brain of normal and C6 glioma‐bearing rats after intracarotid co‐administration of 1‐O‐pentylglycerol (200 mM). To elucidate the mechanisms involved in the alkylglycerol‐mediated BBB opening, intraluminal accumulation of fluorescein isothiocyanate (FITC)–dextran 40,000 was studied in freshly isolated rat brain capillaries using confocal microscopy during incubation with different alkylglycerols. Furthermore, 1‐O‐pentylglycerol‐induced increase in delivery of methotrexate (MTX) to the brain was evaluated in nude mice.

Microscopic evaluation showed a marked 1‐O‐pentylglycerol‐induced extravasation of fluorescein and RB 200–albumin in the ipsilateral normal brain. In glioma‐bearing rats, increased tissue fluorescence was found in both tumor tissue and brain surrounding tumor. Confocal microscopy revealed a time‐ and concentration‐dependent accumulation of FITC–dextran 40,000 within the lumina of isolated rat brain capillaries during incubation with 1‐O‐pentylglycerol and 2‐O‐hexyldiglycerol, indicating enhanced paracellular transfer via tight junctions. Intracarotid co‐administration of MTX and 1‐O‐pentylglycerol (200 mM) in nude mice resulted in a significant increase in MTX concentrations in the ipsilateral brain as compared to controls without 1‐O‐pentylglycerol (P<0.005).

In conclusion, 1‐O‐pentylglycerol increases delivery of small and large compounds to normal brain and brain tumors and this effect is mediated at least in part by enhanced permeability of tight junctions.

British Journal of Pharmacology (2003) 140, 1201–1210. doi:10.1038/sj.bjp.0705554
Ouabain exerts biphasic effects on connexin functionality and expression in vascular smooth muscle cells
Authors: Martin Patricia E M , Hill Nathan S , Kristensen Bo , Errington Rachael J , Griffith Tudor M
Published: November 2003

We have compared the effects of ouabain on the maintenance of gap junctional communication in rat aortic A7r5 smooth muscle cells, monkey COS‐1 fibroblasts and human HeLa epithelial cells.

Ouabain (1 mM) interrupted dye coupling between confluent A7r5 cells within ∼1 h, and high concentrations of ouabain were similarly required to reduce coupling between COS‐1 cells selected to express the rat α1 Na+/K+‐ATPase subunit, which is ouabain resistant. By contrast, low concentrations of ouabain (1–10 μM) attenuated dye transfer in wild‐type COS‐1 and HeLa cells, whose endogenous α1 subunits possess relatively high affinity for the glycoside (Ki∼0.3 vs ∼100 μM) Ouabain‐induced reductions in dye transfer therefore correlated with the ability of the glycoside to bind to the Na+/K+‐ATPase isoenzymes expressed in these different cell lines.

No consistent relationship between inhibition of intercellular dye transfer and secondary changes in [Ca2+]i or pHi could be identified following incubation with ouabain.

In separate experiments, the effects of ouabain on real‐time trafficking of connexin protein were monitored by time‐lapse microscopy of A7r5 cells transfected to express a fluorescent Cx43‐green fluorescent protein (GFP) and the ability of the glycoside to modulate endogenous expression of connexins (Cx) 40 and 43 evaluated in A7r5 cells by immunochemical and Western blot analysis.

Ouabain (1 mM) depressed vesicular trafficking of Cx43‐GFP after ∼1 h, and caused a time‐dependent loss of endogenous Cx40 and Cx43 protein that was first evident at 2 h and almost complete after 4 h. These effects of ouabain on Cx expression were reversed ∼90 min following washout of the glycoside.

We conclude that ouabain exerts biphasic effects on the intercellular communication that involve an initial decrease in gap junctional permeability followed by a global reduction in the expression of Cx protein. Further studies are necessary to establish to what extent these actions of ouabain reflect inversion of the normal [Na+]i/[K+]i ratio and/or conversion of the Na+/K+‐ATPase into a general signal transducer that regulates downstream protein synthesis.

British Journal of Pharmacology (2003) 140, 1261–1271. doi:10.1038/sj.bjp.0705556
IL‐13 enhances agonist‐evoked calcium signals and contractile responses in airway smooth muscle
Authors: Tliba Omar , Deshpande Deepak , Chen Hang , Van Besien Christopher , Kannan Mathur , Panettieri Reynold A , Amrani Yassine
Published: November 2003

Growing evidence suggests that interleukin (IL)‐13, a Th2‐type cytokine, plays a critical role in the development of bronchial hyper‐responsiveness (BHR), an essential feature of asthma, although the underlying mechanisms remain unknown. In the present study, we investigated whether IL‐13 directly affects airway smooth muscle (ASM) function. In murine tracheal rings, IL‐13 (100 ng ml−1, 24 h) significantly increased both the carbachol‐ and KCl‐induced maximal force generation without affecting ASM sensitivity. In cultured human ASM cells, IL‐13 (50 ng ml−1, 24 h) also augmented cytosolic calcium levels to bradykinin, histamine and carbachol by 60, 35 and 26%, respectively. The present study demonstrates that IL‐13 may promote BHR by directly modulating ASM contractility, an effect that may be due to enhanced G protein‐coupled receptor (GPCR)‐associated calcium signaling.

British Journal of Pharmacology (2003) 140, 1159–1162. doi:10.1038/sj.bjp.0705558
Verotoxin activates mitogen‐activated protein kinase in human peripheral blood monocytes: role in apoptosis and proinflammatory cytokine release
Authors: Cameron Pamela , Smith Susan J , Giembycz Mark A , Rotondo Dino , Plevin Robin
Published: November 2003

In this study, we examined the role of mitogen‐activated protein (MAP) kinases in the effects of verotoxins (VTs), from Escherichia coli O157:H7, upon both apoptosis and the release of tumour necrosis factor alpha (TNF‐α) and granulocyte–macrophage colony‐stimulated factor (GM‐CSF) from human monocytes.

Both VT1 and VT2 stimulated a weak, transient increase in c‐Jun‐N‐terminal kinase (JNK) activity and a strong activation of both p38 mitogen‐activated protein kinase (MAP kinase) and extracellular‐regulated kinase (ERK) activity in human monocytes, which was sustained in the case of p38 MAP kinase.

Stimulation of human monocytes with VT2 (100 ng ml−1) did not result in an increase in apoptosis; however, the toxin stimulated the release of both TNF‐α and GM‐CSF.

Pretreatment of human monocytes with the p38 MAP kinase inhibitor SB203580, at concentrations from 100 nM to 10 μM, significantly decreased the VT1‐ and VT2‐induced TNF‐α and GM‐CSF release from monocytes. In contrast, inhibition of MEK1 with PD98059 only significantly decreased GM‐CSF release.

Pretreatment of monocytes with SP600125 inhibited both GM‐CSF and TNF‐α production; however, significant effects upon p38 MAP kinase and ERK activation were observed.

Taken together, these results suggest a role for p38 MAP kinase and ERK in cytokine generation in response to the verotoxins. A role for JNK remains undetermined.

British Journal of Pharmacology (2003) 140, 1320–1330. doi:10.1038/sj.bjp.0705560
Characterisation of marrubenol, a diterpene extracted from Marrubium vulgare, as an L‐type calcium channel blocker
Authors: El Bardai Sanae , Wibo Maurice , Hamaide Marie‐Christine , Lyoussi Badiaa , Quetin‐Leclercq Joëlle , Morel Nicole
Published: November 2003

The objective of the present study was to investigate the mechanism of the relaxant activity of marrubenol, a diterpenoid extracted from Marrubium vulgare. In rat aorta, marrubenol was a more potent inhibitor of the contraction evoked by 100 mM KCl (IC50: 11.8±0.3 μM, maximum relaxation: 93±0.6%) than of the contraction evoked by noradrenaline (maximum relaxation: 30±1.5%).

In fura‐2‐loaded aorta, marrubenol simultaneously inhibited the Ca2+ signal and the contraction evoked by 100 mM KCl, and decreased the quenching rate of fura‐2 fluorescence by Mn2+.

Patch‐clamp data obtained in aortic smooth muscle cells (A7r5) indicated that marrubenol inhibited Ba2+ inward current in a voltage‐dependent manner (KD: 8±2 and 40±6 μM at holding potentials of −50 and −100 mV, respectively).

These results showed that marrubenol inhibits smooth muscle contraction by blocking L‐type calcium channels.

British Journal of Pharmacology (2003) 140, 1211–1216. doi:10.1038/sj.bjp.0705561
Docosahexaenoic acid and other fatty acids induce a decrease in pHi in Jurkat T‐cells
Authors: Aires Virginie , Hichami Aziz , Moutairou Kabirou , Khan Naim Akhtar
Published: November 2003

Docosahexaenoic acid (DHA) induced rapid (t1/2=33 s) and dose‐dependent decreases in pHi in BCECF‐loaded human (Jurkat) T‐cells. Addition of 5‐(N,N‐dimethyl)‐amiloride, an inhibitor of Na+/H+ exchanger, prolonged DHA‐induced acidification as a function of time, indicating that the exchanger is implicated in pHi recovery.

Other fatty acids like oleic acid, arachidonic acid, eicosapentaenoic acid, but not palmitic acid, also induced a fall in pHi in these cells.

To assess the role of calcium in the DHA‐induced acidification, we conducted experiments in Ca2+‐free (0% Ca2+) and Ca2+‐containing (100% Ca2+) buffer. We observed that there was no difference in the degree of DHA‐induced transient acidification in both the experimental conditions, though pHi recovery was faster in 0% Ca2+ medium than that in 100% Ca2+ medium.

In the presence of BAPTA, a calcium chelator, a rapid recovery of DHA‐induced acidosis was observed. Furthermore, addition of CaCl2 into 0% Ca2+ medium curtailed DHA‐evoked rapid pHi recovery. In 0% Ca2+ medium, containing BAPTA, DHA did not evoke increases in [Ca2+]i, though this fatty acid still induced a rapid acidification in these cells. These observations suggest that calcium is implicated in the long‐lasting DHA‐induced acidosis.

DHA‐induced rapid acidification may be due to its deprotonation in the plasma membrane (flip‐flop model), as suggested by the following observations: (1) DHA with a –COOH group induced intracellular acidification, but this fatty acid with a –COOCH3 group failed to do so, and (2) DHA, but not propionic acid, ‐induced acidification was completely reversed by addition of fatty acid‐free bovine serum albumin in these cells.

These results suggest that DHA induces acidosis via deprotonation and Ca2+ mobilization in human T‐cells.

British Journal of Pharmacology (2003) 140, 1217–1226. doi:10.1038/sj.bjp.0705563
Affinity adsorbents for the vancomycin group of antibiotics
Authors: Yan Husheng , Zhao Qingxiang , Yuan Jing , Cheng Xiaohui , He Binglin
Published: November 2003

The vancomycin group of antibiotics kill Gram‐positive bacteria by binding to nascent bacterial cell‐wall peptidoglycan bearing the C‐terminal sequence‐D‐Ala‐D‐Ala. In this paper, affinity adsorbents for the vancomycin group of antibiotics were prepared by immobilizing the peptidoglycan analogues ‐D‐Ala‐D‐Ala, ‐succinyl‐D‐Ala and ‐succinyl‐Gly on to crosslinked poly(N,N‐dimethylacrylamide). The adsorption capacities of the three adsorbents for demethylvancomycin were 0.59, 0.35 and 0.29 mmol/g, respectively. The adsorption capacity of the adsorbent with‐D‐Ala‐D‐Ala for vancomycin was 0.53 mmol/g. In contrast, the adsorbent bearing ‐succinyl‐L‐Ala hardly adsorbed demethylvancomycin. Aqueous sodium carbonate (0.4 M)/acetonitrile (7/3, v/v) completely desorbed demethylvancomycin adsorbed on the adsorbents.
Bioconversion of D‐galactose into D‐tagatose by expression of L‐arabinose isomerase
Authors: Roh Hoe J. , Kim Pil , Park Yong C. , Choi Jin H.
Published: November 2003

D‐Tagatose is a potential bulking agent in food as a non‐calorific sweetener. To produce D‐tagatose from cheaper resources, plasmids harbouring the L‐arabinose isomerase gene (araA) fromEscherichia coli,Bacillus subtilisandSalmonella typhimuriumwere constructed because L‐arabinose isomerase was suggested previously as an enzyme that mediates the bioconversion of galactose into tagatose as well as that of arabinose to ribulose. The constructed plasmids were named pTC101, pTC105 and pTC106, containingaraAfromE. coli,B. subtilisandS. typhimuriumrespectively. In the cultures of recombinantE. coliwith pTC101, pTC105 and pTC106, tagatose was produced from galactose in 9.9, 7.1 and 6.9% yields respectively. The enzyme extract ofE. coliwith the plasmid pTC101 also converted galactose into tagatose with a 96.4% yield.
Endoxylanase II from Trichoderma reesei has several isoforms with different isoelectric points
Authors: Lappalainen Arja , Siika‐Aho Matti , Kalkkinen Nisse , Fagerström Richard , Tenkanen Maija
Published: November 2003

Two minor xylanases present in Trichoderma reesei Rut C30 cultivation broth were purified as a mixture using ion‐exchange, hydrophobic‐interaction and gel chromatography. The purified enzyme preparation contained two active xylanases with pI values of 7.1 and 8.1. Both components had a molecular mass of 20 kDa. The purified xylanase preparation exhibited properties very similar to those of the previously isolated XYL II (pI 9.0) of T. reesei Rut C30. The activity and stability properties, apparent kinetic parameters as well as the titration curve forms were similar. The major difference in enzymic properties was the significantly lower specific activity of the pI‐7.1+8.1 xylanase mixture (3350 nkat/mg) compared with the specific activity of XYL II (13500 nkat/mg). Amino acid sequences of tryptic peptides (34% of the total amino acid sequence was determined) were identical to the amino acid sequence of XYL II. Furthermore, in vitro modification of the pI‐9.0 form of XYL II to pI‐8.1 and pI‐7.1 forms was demonstrated. Thus the purified xylanase preparation most probably contained two modified forms of XYL II. The primary amino acid sequence of XYL II contains 28 glutamine and asparagine residues and theoretically deamination of one of them lowers the pI to 8.06 and deamination of two amino acids lowers the pI to 7.02.
Effective induction, purification and characterization of Trichoderma koningii G‐39 β‐xylosidase with high transferase activity
Authors: Li Yaw‐Kuen , Yao Hsin‐Jan , Cho Yi‐tzu
Published: November 2003

A β‐xylosidase was induced and purified from the culture filtrate of Trichoderma koningii G‐39, grown in a medium containing 1% oat spelts xylan and 0.1% xylose. The presence of xylose unequivocally enhanced the induction of β‐xylosidase. The purified enzyme, which exhibited a significant α‐arabinosidase activity, was obtained with high yield simply via ethanol precipitation and a single anion‐exchange chromatography and was characterized as a monomeric glycoprotein with an estimated molecular mass of 104 kDa and a pI of 4.6. The Km values towards p‐nitrophenyl β‐D‐xylopyranoside and p‐nitrophenyl α‐L‐arabinopyranoside are 0.04 and 7.5 mM, respectively. It is stable at pH 2.5–7.4, 37 °C. The pH and temperature optima are in the range of 3.5–4.0 and 55–60 °C, respectively. Contrary to most β‐xylosidases from other sources, Hg2+ (up to 25 mM) has no effect on enzyme activity. Xylose was shown to inhibit the purified enzyme with a moderate Ki value of 5 mM. The enzyme exhibited transxylosylation activity and was characterized as a ‘retaining’ enzyme, catalysing the hydrolysis of substrate with the retention of anomeric configuration.