bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of winter road maintenance costs using climate data
Authors: Venäläinen Ari , Kangas Markku
Published: March 2003

In Finland, winter road maintenance has been privatised, and the use of reliable predictors to measure the harshness of winter conditions has become even more important. Several indices have been developed to estimate the difficulty of winter conditions; however, many of these indices require relatively complicated input data and are in that sense vulnerable –for example, to changes in the meteorological station network. In the current study the year‐to‐year variation of the climatological variables describing maintenance costs were compared with the variation in costs. This made it possible to make a qualitative interpretation of the costs. This approach is ‘simple enough’ for its use to be easily accepted both by the contractors responsible for winter road maintenance and also by the administrators responsible for covering the maintenance costs. Copyright © 2003 Royal Meteorological Society
Development and testing of a high resolution mountain‐wave forecasting system
Authors: Vosper Simon
Published: March 2003

A three‐dimensional numerical model for mountain waves is described and validated against radiosonde observations over the Isle of Arran, south‐west Scotland. The model is based on the Boussinesq equations of motion linearised about a background profile of wind, potential temperature and density. The equations are discretised using finite‐difference approximations and the time dependence is retained. Solutions are then computed by integrating forward the equations in time until a stationary mountain‐wave field is obtained. Data from radiosondes, launched during fieldwork on Arran during February and March 2000, are used to represent the background flow and model simulations of the wave field are compared directly with fluctuations in the ascent rates of the balloons. On average, the model reproduces the observed maximum peak‐to‐peak vertical velocity to within about 0.6 ms−1. In many cases the accuracy of the simulations is even better than this: the model vertical velocity along the path of the radiosondes agree well with fluctuations in the balloon ascent rate. The sensitivity of the model results to the wave ‘launching height’ is discussed. The model was also used to provide forecasts of wave activity during the field campaign. In this case, rather than using radiosonde data to represent the background flow, data were extracted from a global forecast model. The accuracy of these forecasts is examined and the viability of using such a model to provide routine operational high‐resolution mountain‐wave forecasts for specific sites is discussed. Copyright © 2003 Royal Meteorological Society
A diagnostic analysis of the Río de la Plata Superstorm, May 2000
Authors: Possia Norma , Bibiana Ceme S. , Campetella Claudia
Published: March 2003

On 16 May 2000, a low pressure system produced very intense winds over the Río de la Plata (RP) river, giving rise to floods within the region. In order to study this event, the synoptic evolution of the cyclone of 14–17 May 2000 is documented using conventional observations and the NCEP analysed data sets. The synoptic–dynamic overview reveals that the system starts as a usual cyclogenesis on the Chilean coast. The low level cyclone favours a convectively unstable environment within the central Argentinean region triggering convective storms and, consequently, a large amount of latent‐heat release. The latent heat and the vorticity advection both play an important role in determining the depth of the system and its movement. Another unusual feature of this event is the north‐eastward displacement of the cyclone, which is attributed to the interaction with other low‐pressure systems located in the South Atlantic Ocean. Copyright © 2003 Royal Meteorological Society
Animal colour vision — behavioural tests and physiological concepts
Authors: KELBER ALMUT , VOROBYEV MISHA , OSORIO DANIEL
Published: March 2003

Over a century ago workers such as J. Lubbock and K. von Frisch developed behavioural criteria for establishing that non‐human animals see colour. Many animals in most phyla have since then been shown to have colour vision. Colour is used for specific behaviours, such as phototaxis and object recognition, while other behaviours such as motion detection are colour blind. Having established the existence of colour vision, research focussed on the question of how many spectral types of photoreceptors are involved. Recently, data on photoreceptor spectral sensitivities have been combined with behavioural experiments and physiological models to study systematically the next logical question: ‘what neural interactions underlie colour vision ?‘This review gives an overview of the methods used to study animal colour vision, and discusses how quantitative modelling can suggest how photoreceptor signals are combined and compared to allow for the discrimination of biologically relevant stimuli.
Identification, measurement and interpretation of tree rings in woody species from mediterranean climates
Authors: CHERUBINI PAOLO , GARTNER BARBARA L. , TOGNETTI ROBERTO , BRÄKER OTTO U. , SCHOCH WERNER , INNES JOHN L.
Published: March 2003

We review the literature dealing with mediterranean climate, vegetation, phenology and ecophysiology relevant to the understanding of tree‐ring formation in mediterranean regions. Tree rings have been used extensively in temperate regions to reconstruct responses of forests to past environmental changes. In mediterranean regions, studies of tree rings are scarce, despite their potential for understanding and predicting the effects of global change on important ecological processes such as desertification. In mediterranean regions, due to the great spatio‐temporal variability of mediterranean environmental conditions, tree rings are sometimes not formed. Often, clear seasonality is lacking, and vegetation activity is not always associated with regular dormancy periods. We present examples of tree‐ring morphology of five species (Arbutus unedo, Fraxinus ornus, Quercus cerris, Q. ilex, Q. pubescens) sampled in Tuscany, Italy, focusing on the difficulties we encountered during the dating. We present an interpretation of anomalies found in the wood structure and, more generally, of cambial activity in such environments. Furthermore, we propose a classification of tree‐ring formation in mediterranean environments. Mediterranean tree rings can be dated and used for dendrochronological purposes, but great care should be taken in selecting sampling sites, species and sample trees.
A sigmoidal transcriptional response: cooperativity, synergy and dosage effects
Authors: VEITIA REINER A.
Published: March 2003

A sigmoidal transcriptional response (STR) is thought to act as amolecular switch to control gene expression. This nonlinear behaviour arises as a result of the cooperative recognition of a promoter/enhancer by transcription factors (TFs) and/or their synergy to attract the basal transcriptional machinery (BTM). Although this cooperation between TFs is additive in terms of energy, it leads to an exponential increase in affinity between the BTM and the pre‐initiation complexes. This exponential increase in the strength of interactions is the principle that governs synergistic systems. Here, I propose a minimalist quasi‐equilibrium model to explore qualitatively the STR taking into account cooperative recognition of the promoter/enhancer and synergy. Although the focus is on the effect of activators, a similar treatment can be applied to inhibitors. One of the main insights obtained from the model is that generation of a sigmoidal threshold is possible even in the absence of cooperative DNA binding provided the TFs synergistically interact with the BTM. On the contrary, when there is cooperative binding, the impact of synergy diminishes. It will also be shown that a sigmoidal response to a morphogenetic gradient can be used to generate a nested gradient of another morphogen. Previously, I had proposed that halving the amounts of TFs involved in sigmoidal transcriptional switches could account for the abnormal dominant phenotypes associated with some of these genes. This phenomenon, called haploinsufficiency (HI), has been recognised as the basis of many human diseases. Although a formal proof linking HI and a sigmoidal response is lacking, it is tempting to explore the model from the perspective of dosage effects.
Three optimisations for sharing
Authors: HOWE JACOB M. , KING ANDY
Published: March 2003

To improve precision and efficiency, sharing analysis should track both freeness and linearity.
The abstract unification algorithms for these combined domains are suboptimal, hence there
is scope for improving precision. This paper proposes three optimisations for tracing sharing
in combination with freeness and linearity. A novel connection between equations and sharing
abstractions is used to establish correctness of these optimisations even in the presence of
rational trees. A method for pruning intermediate sharing abstractions to improve efficiency
is also proposed. The optimisations are lightweight and therefore some, if not all, of these
optimisations will be of interest to the implementor.
Composing programs in a rewriting logic for
declarative programming
Authors: MOLINA-BRAVO J. M. , PIMENTEL E.
Published: March 2003

Constructor-Based Conditional Rewriting Logic is a general framework for integrating
first-order functional and logic programming which gives an algebraic semantics for nondeterministic
functional-logic programs. In the context of this formalism, we introduce a
simple notion of program module as an open program which can be extended together
with several mechanisms to combine them. These mechanisms are based on a reduced set of
operations. However, the high expressiveness of these operations enable us to model typical
constructs for program modularization like hiding, export/import, genericity/instantiation,
and inheritance in a simple way. We also deal with the semantic aspects of the proposal by
introducing an immediate consequence operator, and studying several alternative semantics
for a program module, based on this operator, in the line of logic programming: the operator
itself, its least fixpoint (the least model of the module), the set of its pre-fixpoints (term
models of the module), and some other variations in order to find a compositional and fully
abstract semantics w.r.t. the set of operations and a natural notion of observability.
A framework for compiling preferences
in logic programs
Authors: DELGRANDE JAMES P. , SCHAUB TORSTEN , TOMPITS HANS
Published: March 2003

We introduce a methodology and framework for expressing general preference information in
logic programming under the answer set semantics. An ordered logic program is an extended
logic program in which rules are named by unique terms, and in which preferences among
rules are given by a set of atoms of form s [pr ] t where s and t are names. An ordered logic
program is transformed into a second, regular, extended logic program wherein the preferences
are respected, in that the answer sets obtained in the transformed program correspond with
the preferred answer sets of the original program. Our approach allows the specification
of dynamic orderings, in which preferences can appear arbitrarily within a program. Static
orderings (in which preferences are external to a logic program) are a trivial restriction of
the general dynamic case. First, we develop a specific approach to reasoning with preferences,
wherein the preference ordering specifies the order in which rules are to be applied. We
then demonstrate the wide range of applicability of our framework by showing how other
approaches, among them that of Brewka and Eiter, can be captured within our framework.
Since the result of each of these transformations is an extended logic program, we can make
use of existing implementations, such as dlv and smodels. To this end, we have developed a
publicly available compiler as a front-end for these programming systems.
Two results for prioritized logic programming
Authors: ZHANG YAN
Published: March 2003

Prioritized default reasoning has illustrated its rich expressiveness and flexibility in knowledge
representation and reasoning. However, many important aspects of prioritized default
reasoning have yet to be thoroughly explored. In this paper, we investigate two properties of
prioritized logic programs in the context of answer set semantics. Specifically, we reveal a close
relationship between mutual defeasibility and uniqueness of the answer set for a prioritized
logic program. We then explore how the splitting technique for extended logic programs can
be extended to prioritized logic programs. We prove splitting theorems that can be used to
simplify the evaluation of a prioritized logic program under certain conditions.
Workplace trauma and the law
Authors: Tehrani Noreen
Published: March 2003

The law places increasing responsibilities on organizations to protect its workforce from psychological injury. This paper looks at the development of British law relating to traumatic stress and explores a growing concern of clinicians that the law and the legal processes themselves may increase the psychological injury of victims of traumatic stress. The statutory requirement for organizations to provide effective support for employees following a traumatic incident is enshrined in law. However organizations are confused by the conflicting statements on the effectiveness of debriefing and trauma counselling.
NOBEL LECTURE: Yeast and Cancer
Authors: Hartwell Leland H.
Published: March 2003

The discovery of genes that control cell division in yeast, and their relation to cancer, is reviewed.
German version of clinician‐administered PTSD scale
Authors: Schnyder Ulrich , Moergeli Hanspeter
Published: March 2003

This study assessed the reliability of a German translation of the Clinician‐Administered PTSD Scale (CAPS) by using data from 45 survivors of accidents who were hospitalized at the department of traumatology of a university hospital. Assessments were carried out 5 days (Time 1) and 6 months (Time 2) after the accident. Internal consistency proved to be comparable to that of the original English version: Cronbach's alpha was .88 at'T1 and .92 at T2 for the CAPS total score. The CAPS correlated significantly with the validated German version of the Impact of Event Scale (lES) (T1: r = .56, T2: r = .78). The data suggest that the German version of the CAPS is a reliable instrument for the assessment of posttraumatic stress disorder symptomatology in accident victims. Further studies are necessary' to validate further the questionnaire.
Making sense of repetition phenomena by integrating psychotraumatology and psychodynamic psychotherapy
Authors: Ørner Roderick J. , Stolz Peter
Published: March 2003

Psychotherapy and psychotraumatology share a preoccupation with repetition phenomena, manifested as transference, compulsions to repeat, or intrusive reexperiencing. Terminological diversity obscures compelling similarities between these repetition phenomena and discourages speculation about processes involved in their genesis. This paper remedies these oversights by integrating recent empirical evidence pertaining to memory with European intellectual traditions embraced by its pioneering dynamic psychotherapists. Using dreams as a prototype repetition, the phenomenological diversity of repetition phenomena is shown to be reconcilable with current evidence about memory encoding, storage, and retrieval. Differences in persistence, intensity, pervasiveness, and treatment resilience of repetition phenomena are explained using concepts derived from psychological and biological sciences. Implications for psychotherapeutic theory, practice, and evaluation are considered.
Posttraumatic sequelae in a community hit by an avalanche
Authors: Finnsdottir Thorunn , Elklit Ask
Published: March 2003

The posttraumatic sequelae for 104 adult inhabitants from the town of Flateyri. Iceland, were studied 10 weeks after an avalanche hit the town killing 20 people. Eighty‐seven adults from the neighboring town of Thingeyri constituted a control group. On the basis of the General Health Questionnaire (GHQ‐30), 25% of the Flateyri group (twice as many than in Thingeyri) reached a level of psychiatric caseness. The most common symptoms were intrusive thoughts and feelings, tension, sadness, and anxiety. The loss of family members was associated with symptomatology. A high number of former life events correlated more strongly with distress symptoms than with the individual appraisal of these events. Distress symptoms were related to gender, age, and education.
Unknown peaks in GC‐MS analyses of Guthrie cards blood samples might be the result of sample contamination by the black markings of the card
Authors: Brune T. G. , Lambrecht A. Ch. , Koch H. G.
Published: March 2003

Azelaic acid, sometimes found during analysis of Guthrie card blood samples, may be derived from the printing ink used to mark the spotting area.
Introduction of a ketogenic diet in young infants
Authors: Klepper J. , Leiendecker B. , Bredahl R. , Athanassopoulos S. , Heinen F. , Gertsen E. , Flörcken A. , Metz A. , Voit T.
Published: March 2003

The ketogenic diet is a rational treatment for pyruvate dehydrogenase complex deficiency (McKusick 312170) and GLUT1 deficiency syndrome (McKusick 138140). An increasing number of patients are diagnosed in early infancy, but few data are available on the introduction of a ketogenic diet in this age group. GLUT1 deficiency syndrome was suspected in four infants presenting with seizures and unexplained hypoglycorrhachia. A ketogenic diet was introduced at 6–28 weeks of age. Ketosis was initiated by fasting, monitored by bedside blood glucose and 3‐hydroxybutyrate determinations, and was maintained successfully using supplemented carbohydrate‐free infant formula and emulgated triglycerides. All patients developed ketosis within 24 h. 3‐Hydroxybutyrate concentrations available at the bedside correlated inversely with the base excess. At glucose levels ≤40 mg/dl patients remained asymptomatic in the presence of ketones. The ketogenic formula was tolerated well, parental compliance was good, and all patients remained seizure‐free on the diet. GLUT1 deficiency was confirmed in two patients; the diet was discontinued in the other two patients. In one infant, failure to thrive on medium‐chain triglycerides was effectively reversed using long‐chain triglycerides. Urine dipstick analyses failed to detect ketosis in another infant. Adverse effects of the diet were limited to renal stones in one patient. The ketogenic diet can be introduced and maintained successfully in young infants using long‐chain fat emulsion. Monitoring 3‐hydroxybutyrate at the bedside was useful for metabolic control and superior to urine dipstick analysis. Seizure control was effective and adverse effects were limited, but evaluation of the long‐term effects of the ketogenic diet in this age group must await ongoing studies.
Ramipril treatment in a patient with glycogen storage disease I non‐A
Authors: Giannì M. L. , Bonvissuto M. , Gallieni M. , Testolin C. , Racchi E. , Riva E.
Published: March 2003

We studied the effect of ramipril on proteinuria and mild hypertension in a 21‐year‐old patient affected by glycogen storage disease type I non‐A. After few months of therapy we obtained a decrease in total urine protein excretion that later re‐increased in spite of the high dose of ACE inhibitor. Even if ACE inhibitors are the only effective therapy for GSD I nephropathy, further studies are requested.
CblE type of homocystinuria due to methionine synthase reductase deficiency: Clinical and molecular studies and prenatal diagnosis in two families
Authors: Zavaď'áková P. , Fowler B. , Zeman J. , Suormala T. , Pšistoupilová K. , Kožich V.
Published: March 2003

The cblE type of homocystinuria is a rare autosomal recessive disorder, which manifests with megaloblastic anaemia and developmental delay in early childhood. This disease is caused by a defect in reductive activation of methionine synthase (MTR). Our study was directed at clinical, biochemical, enzymatic and molecular characterization of two Czech patients with the cblE type of homocystinuria. Case 1 involves a 20‐year‐old mentally retarded patient who presented with megaloblastic anaemia at 10 weeks of age. She was treated with folates and vitamin B12, and subsequent attempts to cease administration of folates led to recurrence of megaloblastic anaemia. Biochemical features included severe hyperhomocysteinaemia and hypomethioninaemia and in fibroblasts defective formation of methionine from formate, and no complementation with cblE cells. Subsequent molecular analysis of the methionine synthase reductase (MTRR) gene revealed compound heterozygosity for a transition c.1459G>A (G487R) and a 2 bp insertion (c.1623–1624insTA). Case 2 involves an 8‐year‐old girl with nystagmus and developmental delay in whom megaloblastic anaemia was detected at 11 weeks of age. Severe hyperhomocysteinaemia with normal methionine levels was found and enzymatic and complementation studies confirmed the cblE defect. This patient is homozygous for a 140 bp insertion (c.903–904ins140). The insertion is caused by a T>C transition within intron 6 of the MTRR gene, which presumably leads to activation of an exon splicing enhancer. In the families of both patients, enzymatic and mutation analyses were successfully used for prenatal diagnosis. Our study expands the knowledge of the phenotypic and genotypic variability of the cblE type of homocystinuria and supports the concept that this disorder is caused by mutations in the MTRR gene.
Implementability of Liouville Evolution, Koopman and Banach-Lamperti Theorems in Classical and Quantum Dynamics
Authors: Antoniou I. , Majewski W. A. , Suchanecki Z.
Published: March 2003

We extend the concept of implementability of semigroups of evolution operators associated with dynamical systems to quantum case. We show that such an extension can be properly formulated in terms of Jordan morphisms and isometries on non-commutative Lp spaces. We focus our attention on a non-commutative analog of the Banach-Lamperti theorem.
Cooling Load Density Optimization of an Irreversible Simple Brayton Refrigerator
Authors: Zhou Shengbing , Chen Lingen , Sun Fengrui , Wu Chih
Published: March 2003

The performance optimization of an irreversible simple Brayton refrigerator coupled to constant-temperature heat reservoirs is carried out by taking the cooling load density, i.e., the ratio of cooling load to the maximum specific volume in the cycle, as the optimization objective using finite-time thermodynamics (FTT) or entropy generation minimization (EGM) in this paper. The analytical formulae about the relations between cooling load density and pressure ratio, as well as between coefficient of performance (COP) and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers, and the irreversible compression and expansion losses in the compressor and expander. The influences of the effectiveness of the heat exchangers, the temperature ratio of the reservoirs, and the efficiencies of the compressor and expander on the cooling load density versus COP are provided by numerical examples. The cooling load density optimization is performed by searching the optimum pressure ratio of the compressor, and searching the optimum distribution of heat conductance of the hot- and cold-side heat exchangers for the fixed total heat exchanger inventory. The influences of some design parameters, including the effectiveness of the heat exchangers between the working fluid and heat reservoirs, the efficiencies of compressor and expander, the temperature ratio of heat reservoirs, on the maximum cooling load density, the optimum heat conductance distribution and the optimum pressure ratio are provided by numerical examples. The refrigeration plant design with optimization leads to a smaller size including the compressor, expander, and the hot- and cold-side heat exchangers.
Mechanisms of endothelial dysfunction after ionized radiation: selective impairment of the nitric oxide component of endothelium‐dependent vasodilation
Authors: Soloviev Anatoly I , Tishkin Sergey M , Parshikov Alexander V , Ivanova Irina V , Goncharov Eugene V , Gurney Alison M
Published: March 2003

Gamma radiation impairs vascular function, leading to the depression of endothelium‐dependent vasodilatation. Loss of the nitric oxide (NO) pathway has been implicated, but little is known about radiation effects on other endothelial mediators.

This study investigated the mechanisms of endothelial dysfunction in rabbits subjected to whole‐body irradiation from a cobalt60 source.

The endothelium‐dependent relaxation of rabbit aorta evoked by acetylcholine (ACh) or A23187 was impaired in a dose‐dependent manner by irradiation at 2 Gy or above. Inhibition was evident 9 days post‐irradiation and persisted over the 30 day experimental period.

Endothelium‐independent responses to glyceryl trinitrate (GTN), sodium nitroprusside (SNP) and 3‐morpholino‐sydnonimine (SIN‐1) were suppressed over a similar dose range at 7–9 days post‐irradiation, but recovered fully by 30 days post‐irradiation.

In healthy vessels, ACh‐induced relaxation was inhibited by L‐Nω‐nitroarginine (L‐NA; 3×10−4 M) and charybdotoxin (10−8 M) plus apamin (10−6 M) but resistant to indomethacin, indicating the involvement of NO and endothelium‐derived hyperpolarizing factor (EDHF). Supporting this, ACh caused smooth muscle hyperpolarization that was reduced by L‐NA and charybdotoxin plus apamin.

In irradiated vessels, responses to ACh were insensitive to L‐NA but abolished by charybdotoxin plus apamin, indicating selective loss of NO‐mediated relaxation.

In animals treated shortly after irradiation with the antioxidant, α‐tocopherol acetate, the NO‐dependent relaxation was restored without effect on the EDHF‐dependent component.

The results imply that radiation selectively impairs the NO pathway as a consequence of oxidative stress, while EDHF is able to maintain endothelium‐dependent relaxation at a reduced level.

British Journal of Pharmacology (2003) 138, 837–844. doi:10.1038/sj.bjp.0705079
Inhibition by pentoxifylline of TNF‐α‐stimulated fractalkine production in vascular smooth muscle cells: evidence for mediation by NF‐κB down‐regulation
Authors: Chen Yung‐Ming , Tu Chao‐Jung , Hung Kung‐Yu , Wu Kwan‐Dun , Tsai Tun‐Jun , Hsieh Bor‐Shen
Published: March 2003

Fractalkine is a CX3C chemokine for mononuclear leukocytes that is expressed mainly by vascular cells, and regulated by pro‐inflammatory cytokines. This study investigated signal transduction mechanisms by which tumor necrosis factor (TNF)‐α stimulated fractalkine expression in cultured rat vascular smooth muscle cells (VSMCs), and the modulatory effect of a haemorrheologic agent, pentoxifylline, on its production.

TNF‐α (1–50 ng ml−1) stimulated fractalkine mRNA and protein expression in concentration‐ and time‐dependent manners. Pretreatment with calphostin C (0.4 μM, a selective inhibitor of protein kinase C (PKC), and PD98059 (40 μM), a specific inhibitor of p42/44 mitogen‐activated protein kinase (MAPK) kinase, attenuated TNF‐α‐stimulated fractalkine mRNA and protein expression. In contrast, H‐89 (2 μM), a selective inhibitor of cAMP‐dependent protein kinase, wortmannin (0.5 μM), a selective inhibitor of phosphatidylinositol 3‐kinase, and SB203580 (40 μM), a specific inhibitor of p38 MAPK, had no discernible effect.

The ubiquitin/proteosome inhibitors, MG132 (10 μM) and pyrrolidine dithiocarbamate (200 μM), suppressed activation of NF‐κB as well as stimulation of fractalkine mRNA and protein expression by TNF‐α.

TNF‐α‐activated phosphorylation of PKC was blocked by calphostin C, whereas TNF‐α‐augmented phospho‐p42/44 MAPK and phospho‐c‐Jun levels were reduced by PD98059. Neither calphostin C nor PD98059 affected TNF‐α‐induced degradation of I‐κBα or p65 nuclear translocation.

Pretreatment with pentoxifylline (0.1–1 mg ml−1) decreased TNF‐α‐stimulated fractalkine mRNA and protein expression, which was preceded by a reduction in TNF‐α‐activated phosphorylation of PKC, p42/44 MAPK and c‐Jun as well as degradation of I‐κBα and p65/NF‐κB nuclear translocation.

These data indicate that activation of PKC, p42/44 MAPK kinase, and NF‐κB are involved in TNF‐α‐stimulated fractalkine production in VSMCs. Down‐regulation of the PKC, p42/44 MAPK, and p65/NF‐κB signals by PTX may be therapeutically relevant and provide an explanation for the anti‐fractalkine effect of this drug.

British Journal of Pharmacology (2003) 138, 950–958. doi:10.1038/sj.bjp.0705088
Identification of the di‐pyridyl ketone isonicotinoyl hydrazone (PKIH) analogues as potent iron chelators and anti‐tumour agents
Authors: Becker Erika M , Lovejoy David B , Greer Judith M , Watts Ralph , Richardson Des R
Published: March 2003

In an attempt to develop chelators as potent anti‐tumour agents, we synthesized two series of novel ligands based on the very active 2‐pyridylcarboxaldehyde isonicotinoyl hydrazone (PCIH) group. Since lipophilicity and membrane permeability play a critical role in Fe chelation efficacy, the aldehyde moiety of the PCIH series, namely 2‐pyridylcarboxaldehyde, was replaced with the more lipophilic 2‐quinolinecarboxaldehyde or di‐2‐pyridylketone moieties. These compounds were then systematically condensed with the same group of acid hydrazides to yield ligands based on 2‐quinolinecarboxaldehyde isonicotinoyl hydrazone (QCIH) and di‐2‐pyridylketone isonicotinoyl hydrazone (PKIH). To examine chelator efficacy, we assessed their effects on proliferation, Fe uptake, Fe efflux, the expression of cell cycle control molecules, iron‐regulatory protein‐RNA‐binding activity, and 3H‐thymidine, 3H‐uridine and 3H‐leucine incorporation.

Despite the high lipophilicity of the QCIH ligands and the fact that they have the same Fe‐binding site as the PCIH series, surprisingly none of these compounds were effective. In contrast, the PKIH analogues showed marked anti‐proliferative activity and Fe chelation efficacy. Indeed, the ability of these ligands to inhibit proliferation and DNA synthesis was similar or exceeded that found for the highly cytotoxic chelator, 311. In contrast to the PCIH and QCIH analogues, most of the PKIH group markedly increased the mRNA levels of molecules vital for cell cycle arrest.

In conclusion, our studies identify structural features useful in the design of chelators with high anti‐proliferative activity. We have identified a novel class of ligands that are potent Fe chelators and inhibitors of DNA synthesis, and which deserve further investigation.

British Journal of Pharmacology (2003) 138, 819–830. doi:10.1038/sj.bjp.0705089
Identification of MEK1 as a novel target for the treatment of neuropathic pain
Authors: Ciruela A , Dixon A K , Bramwell S , Gonzalez M I , Pinnock R D , Lee K
Published: March 2003

In the present study we have attempted to identify changes in gene expression which are associated with neuropathic pain using subtractive suppression hybridization analysis of the lumbar spinal cord of animals suffering streptozocin induced diabetic neuropathy.

Using this approach, we found a significant up‐regulation of several key components of the extracellular signal‐regulated kinase (ERK) cascade. These findings were confirmed by Western blot analysis, which demonstrated that the levels of active ERK1 and 2 correlated with the onset of streptozocin‐induced hyperalgesia.

Intrathecal administration of the selective MAPK/ERK‐kinase (MEK) inhibitor PD 198306 dose‐dependently (1–30 μg) blocked static allodynia in both the streptozocin and the chronic constriction injury (CCI) models of neuropathic pain.

The antihyperalgesic effects of PD 198306, in both the streptozocin and CCI models of neuropathic pain, correlated with a reduction in the elevated levels of active ERK1 and 2 in lumbar spinal cord.

Intraplantar administration of PD 198306 had no effect in either model of hyperalgesia, indicating that changes in the activation of ERKs and the effect of MEK inhibition are localized to the central nervous system.

In summary, we have demonstrated for the first time that the development of neuropathic pain is associated with an increase in the activity of the MAPK/ERK‐kinase cascade within the spinal cord and that enzymes in this pathway represent potential targets for the treatment of this condition.

British Journal of Pharmacology (2003) 138, 751–756. doi:10.1038/sj.bjp.0705103
Preservation of vascular contraction during ageing: dual effect on calcium handling and sensitization
Authors: Matz Rachel L , Sotomayor Maria Alvarez de , Schott Christa , Andriantsitohaina Ramaroson
Published: March 2003

The present study was aimed to characterize the effects of ageing on vascular contraction by noradrenaline in rat isolated arteries. The existence of vascular bed heterogeneity was investigated in endothelium‐denuded conductance (aorta) and resistance (small mesenteric artery, SMA) arteries, with respect to Ca2+handling, Ca2+sensitization or Ca2+‐independent mechanisms.

In both arteries, contractions to noradrenaline were not different between adult and aged rats.

In Ca2+‐ free medium, noradrenaline elicited a transient increase in tension that was reduced by the Ca2+mobilizing agents, ryanodine and thapsigargin, in arteries from adult rats. A loss of the thapsigargin‐ but not the ryanodine‐sensitive component of noradrenaline‐induced contraction was observed in the two arteries from aged rats.

After depletion of Ca2+stores with noradrenaline, addition of exogenous CaCl2produced a sustained contraction that was decreased to the same extent by the protein kinase C inhibitor, GF 109203X and the tyrosine kinase inhibitor, tyrphostin A‐23, in arteries from adult and aged rats. The Rho‐associated protein kinase inhibitor, Y‐27632, caused identical relaxation of noradrenaline pre‐contracted arteries from both age groups.

Basal intracellular calcium ([Ca2+]i) was higher in SMA from aged than from adult rats. In addition, the noradrenaline [Ca2+]i‐force relationship was significantly shifted to the right in the SMA from aged rats.

Altogether, these data indicate that responsiveness to noradrenaline is preserved both in conductance and resistance arteries with ageing. The latter results from the association of increased basal [Ca2+]i, changes in Ca2+handling at the level of thapsigargin‐sensitive sarcoplasmic reticulum Ca2+‐ATPases and decreased myofilament sensitivity to Ca2+.

British Journal of Pharmacology(2003)138, 745–750. doi:10.1038/sj.bjp.0705104
Role of Th2 responses in the development of allergen‐induced airway remodelling in a murine model of allergic asthma
Authors: Komai Masato , Tanaka Hiroyuki , Masuda Taisei , Nagao Koichi , Ishizaki Masayuki , Sawada Masatsugu , Nagai Hiroichi
Published: March 2003

To clarify the involvement of Th2 responses in the development of allergen‐induced airway remodelling, we investigated the effect of anti‐CD4 monoclonal antibody (mAb) and anti‐CD8 mAb, and the responses of IL‐4 gene‐knockout (KO) mice in a murine model of allergic asthma.

Mice were immunized twice by intraperitoneal injections of ovalbumin (OA), and exposed to aeroallergen (OA, 1% w v−1) for 3 weeks. Twenty‐four hours after the final challenge, airway responsiveness to acetylcholine was measured, and bronchoalveolar lavage (BAL) and histological examinations were carried out.

Anti‐CD4 mAb (1 mg kg−1) clearly inhibited allergen‐induced increases in airway responsiveness to acetylcholine, the number of eosinophils in BAL fluid, serum OA‐specific IgE levels, IL‐13 and transforming growth factor‐β1 levels in BAL fluid, and amount of hydroxyproline in the lung by 100, 99, 100, 100, 84, and 60%, respectively. Furthermore, the antibody (1 mg kg−1) also attenuated allergen‐induced goblet cell hyperplasia in the epithelium and subepithelial fibrosis by 72 and 83%, respectively. In contrast, anti‐CD8 mAb (1 mg kg−1) showed no effect on each parameter. Furthermore, all these parameters were attenuated in IL‐4KO mice by 57, 93, 100, 45, 84 and 60%, and also 72 and 83%, respectively.

These findings suggest that Th2 responses play a critical role for the development of allergen‐induced airway remodelling, and that the inhibition of Th2 responses, e.g. using anti‐CD4 mAb, is a therapeutic approach for the treatment of airway remodelling in asthma.

British Journal of Pharmacology (2003) 138, 912–920. doi:10.1038/sj.bjp.0705105
Protease‐activated receptor (PAR)‐independent growth and pro‐inflammatory actions of thrombin on human cultured airway smooth muscle
Authors: Tran Thai , Stewart Alastair G
Published: March 2003

Thrombin, a mitogen for human cultured airway smooth muscle (HASM), has many actions that have been attributed to activation of protease‐activated receptor (PARs). However, the role of PARs in the proliferative action has not been clearly identified. Moreover, thrombin elicits cytokine production in a number of cell types, but these effects have not been characterized in human ASM.

Thrombin (0.03–3 U ml−1)‐stimulated increases in the levels of the pro‐inflammatory and fibrogenic cytokine, granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) were observed over the same concentration range observed for thrombin‐stimulated mitogenesis.

Inhibition of thrombin proteolytic activity, with either D‐phenylalanyl‐L‐prolyl‐L‐arginine chloromethyl ketone (PPACK)‐ or hirudin‐treated thrombin (0.3 U ml−1) or in the presence of the thrombin serine protease‐selective inhibitor, SDZ 217‐766 (0.15 μM), reduced the thrombin‐stimulated GM‐CSF levels by 91±3, 65±12 and 83±9% (n=8, P<0.05), respectively. PPACK treatment, hirudin and SDZ 217‐766 inhibited thrombin‐stimulated increase in cell number by 70±8, 63±11 and 69±8%, respectively.

PAR‐selective peptides SFLLRN (PAR1; 10 μM), SLIGKV (PAR2; 10 μM), GYPGQV (PAR4; 100 μM) or the combination of SFLLRN and GYPGQV elicited mitogenic responses of only 15% of that to thrombin and surprisingly, had no effect on GM‐CSF levels (n=8). Nevertheless, inhibition of thrombin responses by pertussis toxin (50 ng ml−1) suggests that the PAR‐independent actions also involve a G‐protein‐coupled receptor.

PAR1 receptor expression was evident by immunohistochemistry and these receptors were coupled to increases in intracellular calcium, but not to the phosphorylation of ERK or the increases in cyclin D1 protein levels that are essential for cell proliferation. Cross‐desensitization of intracellular calcium increases by thrombin and the PAR1‐selective peptide provides evidence that the PAR1 receptor responds to both ligands.

The failure of PAR‐selective peptides to mimic thrombin responses together with the inhibition of thrombin responses by serine protease inhibitors suggest the involvement of novel proteolytic receptor targets for thrombin‐induced mitogenesis and cytokine production.

British Journal of Pharmacology (2003) 138, 865–875. doi:10.1038/sj.bjp.0705106
Local anaesthetics have different mechanisms and sites of action at the recombinant N‐methyl‐D‐aspartate (NMDA) receptors
Authors: Sugimoto Masahiro , Uchida Ichiro , Mashimo Takashi
Published: March 2003

Although the principal pharmacological targets of local anaesthetics (LAs) are voltage‐gated Na+ channels, other targets have also been suggested. Here we examined the effects of LAs on the N‐methyl‐D‐aspartate (NMDA) receptor, a receptor involved in the process of nociception.

LAs (bupivacaine, lidocaine, procaine, and tetracaine) reversibly and concentration‐dependently inhibited recombinant ε1/ζ1 and ε2/ζ1 NMDA receptors expressed in Xenopus oocytes (IC50s for bupivacaine, lidocaine, procaine, and tetracaine were 1032.0, 1174.1, 642.1 and 653.8 μM at the ε1/ζ1 receptor; and 1090.8, 1821.3, 683.0 and 662.5 μM respectively (at the ε2/ζ1 receptor). Bupivacaine and procaine were non‐competitive antagonists; bupivacaine possesses non‐competitive and competitive actions when interacting with glycine, whereas procaine has only non‐competitive action.

Mutation of asparagine residue at position 598 (Asp598) in the ζ1 subunit, a residue associated with the blockade site for Mg2+ and ketamine, to glutamine or arginine reduced the sensitivity to procaine but not to bupivacaine. Thus, procaine may interact with sites of action that are closely related to those of Mg2+ and ketamine blockade.

These results suggest that LAs inhibit the NMDA receptor by various mechanisms.

British Journal of Pharmacology (2003) 138, 876–882. doi:10.1038/sj.bjp.0705107
Role of nuclear factor‐κB activation in acute ischaemia‐reperfusion injury in myocardium
Authors: Kis Adrienn , Yellon Derek M , Baxter Gary F
Published: March 2003

Our aims were to characterize activation of the transcription factor, nuclear factor kappa‐B(NF‐κB), during myocardial ischaemia‐reperfusion and to assess its functional role in the evolution of acute ischaemia‐reperfusion injury in intact myocardium in vivo.

Under pentobarbitone anaesthesia, rabbits underwent sham operation, 30 min left coronary artery occlusion followed by 0, 10 or 180 min reperfusion. Saline or NF‐κB inhibitor diethyldithiocarbamic acid (DDTC, 50, 100 or 200 mg kg−1) was given intravenously 5 min prior to reperfusion.

Electromobility shift assay revealed that 30 min ischaemia alone did not activate NF‐κB compared to time‐matched sham‐operated controls (85±13% vs 100±28%, respectively). However, ischaemia plus 10 min reperfusion markedly increased activation of NF‐κB (295±77%). DDTC 50 mg kg−1 did not inhibit NF‐κB activation (278±67%) but at the higher doses complete inhibition was observed (54±20%, 31±16%, respectively).

Infarct to risk ratio was determined by triphenyltetrazolium chloride staining after 30 min ischaemia and 180 min reperfusion. DDTC 50 or 100 mg kg−1 significantly reduced infarct size compared to the saline‐treated control group (34.9±5.2%, 37.1±5.9%, vs 51.3±3.6%, P<0.05, respectively), whereas there was no protection with 200 mg kg−1 (45.6±5.3%).

We conclude that ischaemia alone does not activate NF‐κB, but post‐ischaemic reperfusion robustly activates NF‐κB in the myocardium. DDTC limited irreversible injury at low doses, but this effect appears to be dissociated from inhibition of NF‐κB. Thus, activation of NF‐κB during reperfusion does not appear to play a role in the evolution of myocardial infarction during the early phase of reperfusion.

British Journal of Pharmacology (2003) 138, 894–900. doi:10.1038/sj.bjp.0705108
Expression and functional role of Rho‐kinase in rat urinary bladder smooth muscle
Authors: Wibberley Alexandra , Chen Zunxuan , Hu Erding , Hieble J Paul , Westfall Timothy D
Published: March 2003

The involvement of Rho‐kinase (ROCK) in the contractile mechanisms mediating smooth muscle contraction of the rat urinary bladder was investigated using expression studies and the ROCK inhibitor Y‐27632.

Both isoforms of ROCK (ROCK I and ROCK II) were detected in high levels in rat urinary bladder.

Y‐27632 (10 μM) significantly attenuated contractions of rat urinary bladder strips evoked by the G‐protein coupled receptor agonists carbachol (58.1±10.5% at 0.3 μM) and neurokinin A (68.6±12.7% at 1 μM) without affecting contractions to potassium chloride (10–100 mM). In addition, basal tone was reduced by 47.8±2.0% by 10 μM Y‐27632 in the absence of stimulation.

Contractions of urinary bladder strips evoked by the P2X receptor agonist α,β‐methylene ATP (α,β‐mATP; 10 μM) were also attenuated by Y‐27632 (30.0±7.2% at 10 μM).

Y‐27632 (10 μM) significantly attenuated contractions evoked by electrical field stimulation (2–16 Hz). The effect of Y‐27632 on the tonic portion of the neurogenic response (4–16 Hz) was not significantly different from the effect of atropine (1 μM) alone.

While the mechanism underlying the ability of Y‐27632 to inhibit α,β‐mATP‐evoked contractions remains undetermined, the results of the present study clearly demonstrate a role for ROCK in the regulation of rat urinary bladder smooth muscle contraction and tone.

British Journal of Pharmacology (2003) 138, 757–766. doi:10.1038/sj.bjp.0705109
Neurogenic responses mediated by vanilloid receptor‐1 (TRPV1) are blocked by the high affinity antagonist, iodo‐resiniferatoxin
Authors: Rigoni Michela , Trevisani Marcello , Gazzieri David , Nadaletto Riccardo , Tognetto Michele , Creminon Christophe , Davis John B , Campi Barbara , Amadesi Silvia , Geppetti Pierangelo , Harrison Selena
Published: March 2003

Stimulation of the vanilloid receptor‐1 (TRPV1) results in the activation of nociceptive and neurogenic inflammatory responses. Poor specificity and potency of TRPV1 antagonists has, however, limited the clarification of the physiological role of TRPV1.

Recently, iodo‐resiniferatoxin (I‐RTX) has been reported to bind as a high affinity antagonist at the native and heterologously expressed rat TRPV1. Here we have studied the ability of I‐RTX to block a series of TRPV1 mediated nociceptive and neurogenic inflammatory responses in different species (including transfected human TRPV1).

We have demonstrated that I‐RTX inhibited capsaicin‐induced mobilization of intracellular Ca2+ in rat trigeminal neurons (IC50 0.87 nM) and in HEK293 cells transfected with the human TRPV1 (IC50 0.071 nM).

Furthermore, I‐RTX significantly inhibited both capsaicin‐induced CGRP release from slices of rat dorsal spinal cord (IC50 0.27 nM) and contraction of isolated guinea‐pig and rat urinary bladder (pKB of 10.68 and 9.63, respectively), whilst I‐RTX failed to alter the response to high KCl or SP.

Finally, in vivo I‐RTX significantly inhibited acetic acid‐induced writhing in mice (ED50 0.42 μmol kg−1) and plasma extravasation in mouse urinary bladder (ED50 0.41 μmol kg−1).

In in vitro and in vivo TRPV1 activated responses I‐RTX was ∼3 log units and ∼20 times more potent than capsazepine, respectively. This high affinity antagonist, I‐RTX, may be an important tool for future studies in pain and neurogenic inflammatory models.

British Journal of Pharmacology (2003) 138, 977–985. doi:10.1038/sj.bjp.0705110
Apoptosis and necrosis: two distinct events induced by cadmium in cortical neurons in culture
Authors: López E , Figueroa S , Oset‐Gasque M J , González M P
Published: March 2003

Cadmium is an extremely toxic metal commonly found in industrial workplaces, a food contaminant and a major component of cigarette smoke. Cadmium can severely damage several organs, including the brain. In this work, we have studied both the cadmium toxicity on rat cortical neurons in culture and the possible protective effect of serum.

Our results indicate that: (1) cadmium is taken up by the neurons in a dose and serum dependent way; (2) cadmium, at concentrations from 1 μM or 10 μM (depending on the absence or the presence of serum) up to 100 μM, decreases the metabolic capacity, which was evaluated by the XTT (tetrazolium salt) test; (3) cadmium induces apoptosis and LDH (lactate dehydrogenase) release in a dose dependent way; (4) in a serum‐free medium, the cadmium‐induced apoptosis is accompanied by caspase‐3 activation; (5) both the caspase‐3 activation and the cadmium‐induced apoptosis are reversed by N‐acethyl‐Asp‐Glu‐Val‐Asp‐aldehyde (Ac‐DEVD‐CHO), a selective caspase‐3 inhibitor, indicating that the caspase‐3 pathway is involved in cadmium‐induced apoptosis in cortical neurons; and (6) the cadmium concentrations which produce caspase‐3 activation do not modify the intracellular ATP levels; however, higher cadmium concentrations lead to both intracellular ATP depletion and ATP release, but do not increase the caspase‐3 activity, indicating that cadmium also produces cellular death by necrosis.

These results suggest that cadmium induces either apoptosis or necrosis in rat cortical neurons, depending on the cadmium concentration.

British Journal of Pharmacology (2003) 138, 901–911. doi:10.1038/sj.bjp.0705111