bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of BDNF, NT‐3 and NT‐4 in the developing auditory brainstem
Authors: Hafidi Aziz 
Published: February 2003

AbstractThis study describes the developmental expression of three neurotrophins, brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT‐3) and neurotrophin (NT‐4) in the rat auditory brainstem using immunohistochemistry. At postnatal day 0 (PND 0), neurotrophins expression was virtually absent from all auditory nuclei in the brainstem, even though some positive neurons were observed in the mesencephalic trigeminal nucleus at this age. However, BDNF, NT‐3 and NT‐4 positive neurons were observed in most brainstem auditory nuclei by PND 6. At the following stages, there was a general increase in the intensity of the neurotrophins immunoreactivity and BDNF labeling was particularly prominent in most cochlear nucleus neurons. A differential pattern of staining emerged in cochlear nucleus subdivisions, with more intense staining present in the ventral part. The superior olivary complex nuclei followed a similar pattern of BDNF staining compared to the cochlear nucleus. In the adult, BDNF heavily labeled most neurons of the superior olivary nuclei and moderately labeled neurons of the inferior colliculus (IC). NT‐3 and NT‐4 showed a similar pattern of staining in most auditory brainstem nuclei. The first staining was observed by PND 6 in some neuronal cell bodies. NT‐3 and NT‐4 immunoreactivity increased in the following stages and in the adult moderate labelings were observed in most neurons of the cochlear nucleus, the superior olivary nuclei and the IC.These results show that neurotrophins are expressed 1 week before the onset of hearing and the increase of their expressions correlate with the appearance of sound‐evoked activity in the system. The temporal distribution of neurotrophins does not correlate with neuronal birth, axonal outgrowth or the formation of connection in the auditory structures, suggesting a role primarily in the maintenance and/or modulation of postnatal and adult functions.
Desensitization of β2‐adrenoceptor‐mediated responses by short‐acting β2‐adrenoceptor agonists in human lung mast cells
Authors: Chong Lee K , Suvarna Kim , Chess‐Williams Russell , Peachell Peter T 
Published: February 2003

The principal aim of the present study was to determine whether long‐term treatment of human lung mast cells (HLMC) with the clinically‐relevant β2‐adrenoceptor agonists, salbutamol and terbutaline, leads to desensitization of β2‐adrenoceptor‐mediated responses in these cells.
The non‐selective β‐adrenoceptor agonist, isoprenaline, and the selective β2‐adrenoceptor agonists, salbutamol and terbutaline, inhibited the IgE‐mediated release of histamine from HLMC. Salbutamol (pD2; 7.7±0.3) and terbutaline (pD2; 7.3±0.2) were roughly equipotent as inhibitors of histamine release although both agonists were less potent than isoprenaline (pD2; 8.6±0.2).
Isoprenaline (10−5 M), salbutamol (10−5 M) and terbutaline (10−5 M) enhanced total cell cAMP levels in HLMC over basal by 361±90, 150±38 and 165±35%, respectively.
Long‐term exposure (24 h) of HLMC to either salbutamol (10−7 M) or terbutaline (10−7 M) led to a subsequent reduction in the effectiveness of salbutamol and terbutaline (both 10−9–10−4 M) to inhibit histamine release. However, salbutamol was significantly (P<0.05) more effective than terbutaline at promoting the functional desensitization.
Radioligand binding studies, using iodinated cyanopindolol, were performed to determine β2‐adrenoceptor density in cell membranes after pretreatment (24 h) of cells with either salbutamol (10−6 M) or terbutaline (10−6 M). Both agonists reduced β2‐adrenoceptor density in membranes to about the same extent (∼25% reduction) but these changes in receptor density were not statistically significant (P>0.05).
These data indicate that long‐term exposure of mast cells to salbutamol causes greater levels of desensitization to β2‐adrenoceptor‐mediated responses in HLMC than terbutaline. These findings may have wider clinical significance in the context of asthma treatment as compromised mast cell inhibition could result following long‐term exposure of mast cells to short‐acting bronchodilators.

British Journal of Pharmacology (2003) 138, 512–520. doi:10.1038/sj.bjp.0705050
Heterogeneity of presynaptic muscarinic receptors mediating inhibition of sympathetic transmitter release: a study with M2‐ and M4‐receptor‐deficient mice
Authors: Trendelenburg Anne‐Ulrike , Gomeza Jesus , Klebroff Werner , Zhou Hongxia , Wess Jürgen 
Published: February 2003

Presynaptic muscarinic receptors modulate sympathetic transmitter release. The goal of the present study was to identify the muscarinic receptor subtype(s) mediating inhibition of sympathetic transmitter release in mouse atria, urinary bladder and vas deferens. To address this question, electrically evoked noradrenaline release was assessed using tissue preparations from NMRI, M2‐ and M4‐knockout, and the corresponding M2‐ and M4‐wildtype mice, after preincubation with 3H‐noradrenaline.
The muscarinic agonist carbachol decreased evoked tritium overflow (20 pulses/50 Hz) in each tissue and strain investigated. After deletion of the M2‐receptor the maximal inhibition by carbachol was significantly reduced (by 41–72%), but not abolished, in all tissues. After deletion of the M4‐receptor a moderate and significant reduction of the maximal inhibition by carbachol (by 28%) was observed only in the vas deferens.
Experiments with the muscarinic antagonists methoctramine and pirenzepine confirmed that the presynaptic muscarinic receptors were predominantly M2 in atria and bladder and probably a mixture of M2 and M4 in the vas deferens.
Experiments in the urinary bladder with the cholinesterase inhibitor physostigmine and the muscarinic antagonist ipratropium demonstrated that endogenously released acetylcholine predominantly acted through M2‐receptors to inhibit noradrenaline release. However, the results do not exclude a minor contribution of M4‐receptors to this endogenous inhibition.
In conclusion, our results clearly indicate that the release‐inhibiting muscarinic receptors on postganglionic sympathetic axons in mouse atria, bladder and vas deferens represent mixtures of M2‐ and non‐M2‐receptors. The non‐M2‐receptors remain unknown in atria and the bladder, and may represent primarily M4‐receptors in the vas deferens. These results reveal an unexpected heterogeneity among the muscarinic receptors mediating inhibition of noradrenaline release.

British Journal of Pharmacology (2003) 138, 469–480. doi:10.1038/sj.bjp.0705053
The anti‐inflammatory actions of methotrexate are critically dependent upon the production of reactive oxygen species
Authors: Phillips Darren C , Woollard Kevin J , Griffiths Helen R 
Published: February 2003

The mechanism of action by which methotrexate (MTX) exerts its anti‐inflammatory and immunosuppressive effects remains unclear. The aim of this study is to investigate the hypothesis that MTX exerts these effects via the production of reactive oxygen species (ROS).
Addition of MTX (100 nM–10 μM) to U937 monocytes induced a time and dose dependent increase in cytosolic peroxide [peroxide]cyt from 6–16 h. MTX also caused corresponding monocyte growth arrest, which was inhibited (P<0.05) by pre‐treatment with N‐acetylcysteine (NAC; 10 mM) or glutathione (GSH; 10 mM). In contrast, MTX induction of [peroxide]cyt in Jurkat T cells was more rapid (4 h; P<0.05), but was associated with significant apoptosis at 16 h at all doses tested (P<0.05) and was significantly inhibited by NAC or GSH (P<0.05).
MTX treatment of monocytes (10 nM–10 μM) for 16 h significantly reduced total GSH levels (P<0.05) independently of dose (P>0.05). However, in T‐cells, GSH levels were significantly elevated following 30 nM MTX treatment (P<0.05) but reduced by doses exceeding 1 μM compared to controls (P<0.05).
MTX treatment significantly reduced monocyte adhesion to 5 h and 24 h LPS (1 μg ml−1) activated human umbilical vein endothelial cells (HUVEC; P<0.05) but not to resting HUVEC. Pre‐treatment with GSH prevented MTX‐induced reduction in adhesion.
In conclusion, ROS generation by MTX is important for cytostasis in monocytes and cytotoxicity T‐cells. Furthermore, MTX caused a reduction in monocyte adhesion to endothelial cells, where the mechanism of MTX action requires the production of ROS. Therefore its clinical efficacy can be attributed to multiple targets.

British Journal of Pharmacology (2003) 138, 501–511. doi:10.1038/sj.bjp.0705054
Regulated and constitutive activation of specific signalling pathways by the human S1P5 receptor
Authors: Niedernberg Anke , Blaukat Andree , Schöneberg Torsten , Kostenis Evi 
Published: February 2003

We tested the hypothesis, whether G Protein‐coupled receptors (GPCRs) may differentially regulate specific signalling pathways by constitutive and agonist‐induced activation using the human sphingosine 1‐phosphate receptor S1P5 as a model.
S1P5 receptor‐expressing HEK293 cells exhibited a high degree of basal activity for both inhibition of adenylyl cyclase and extracellular signal regulated kinase (ERK) when cultured in serum, which contains high levels of sphingosine 1‐phosphate (S1P). However, basal activity was independent of the presence of S1P: (i) constitutive activity remained when cells were cultured in delipidated serum, (ii) addition of S1P to delipidated serum did not increase basal S1P5 receptor signalling.
Conversely, constitutive inhibition of forskolin‐stimulated adenylyl cyclase was further enhanced by S1P in S1P5‐HEK293 cells.
Transfection of several mammalian cell lines (CHO‐K1, HEK293, NIH‐3T3, RH7777) with the S1P5 receptor induced cell rounding, which was more pronounced in the presence of S1P‐containing serum. Rounded cell morphology did not correlate with apoptotic cell death, but led to detachment of cells.
Cell surface ELISA assays showed that a fraction of plasma membrane S1P5 receptors were dose‐dependently internalized with S1P.
These data reveal that intrinsic inhibition of unstimulated adenylyl cyclase or ERK activity by the S1P5 receptor is insensitive to ligand modulation. Conversely, effects on forskolin‐stimulated adenylyl cyclase, cell morphology and internalization can be further augmented with S1P. Our results suggest that different signal transduction pathways are not equally activated through constitutively active GPCRs with promiscuous signalling characteristics.

British Journal of Pharmacology (2003) 138, 481–493. doi:10.1038/sj.bjp.0705055
Characterization of human 5‐HT4(d) receptor desensitization in CHO cells
Authors: Mialet Jeanne , Fischmeister Rodolphe , Lezoualc'h Frank 
Published: February 2003

Serotonin 5‐HT4 receptor isoforms differ in their C‐terminal tail and yet little is known about their regulation. In this study, we investigated the desensitization of two human 5‐HT4 receptors stably expressed in CHO cells, with a special emphasis on the h5‐HT4(d) isoform.
Exposure of h5‐HT4(d) and h5‐HT4(e) receptors to 1 μM 5‐HT induced a rapid desensitization of the adenylyl cyclase response. The h5‐HT4(d) receptor desensitized with a faster rate (t1/2<5 min) than the h5‐HT4(e) receptor (t1/2=15 min) and after 10 min 5‐HT treatment cAMP production was reduced by ∼70%.
5‐HT‐induced h5‐HT4(d) receptor desensitization was mimicked by 8‐Bromo‐cAMP, a cAMP analogue, and was inhibited by [n‐[2‐(p‐bromocinnamylamino)ethyl]‐5‐isoquinolinesulphonamide, 2HCl] (H‐89), an inhibitor of cAMP‐dependent protein kinase (PKA). Inhibitors of endocytosis (sucrose, 0.45 M and concanavaline A, 0.25 mg ml−1) partially reversed the h5‐HT4(d) receptor desensitization process.
Given the prominent role of PKA in agonist‐induced desensitization, we mutated the four putative PKA phosphorylation sites present in the third intracellular loop (Ser242, Thr253, Thr255) and the C terminal tail (Ser338) of the h5‐HT4(d) receptor. Surprisingly, mutated receptors in which either one or all four putative phosphorylation sites were substituted to alanine did not impair receptor desensitization suggesting that PKA might act on nonconsensus sites.
Altogether, our data demonstrate that the C‐terminal tail of h5‐HT4 receptors may influence the rate of agonist‐induced desensitization and we provide evidence for a major role of PKA in h5‐HT4(d) receptor desensitization.

British Journal of Pharmacology (2003) 138, 445–452. doi:10.1038/sj.bjp.0705061
Sphingosylphosphorylcholine, a naturally occurring lipid mediator, inhibits human platelet function
Authors: Altmann Christoph , Meyer zu Heringdorf Dagmar , Böyükbas Dilek , Haude Michael , Jakobs Karl H , Michel Martin C 
Published: February 2003

The lysophospholipids, lysophosphatidic acid and sphingosine 1‐phosphate, have been reported to activate platelets. Here we examined effects of the naturally occurring related sphingosylphosphorylcholine (SPC) on human platelet function.
Platelet activation was determined as aggregation, elevation of intracellular Ca2+ concentrations, surface expression of P‐selectin, GP 53, and GP IIb/IIIa neoepitope PAC‐1, and of fibrinogen binding to the platelet surface.
Platelets were activated by ADP (5 and 20 μM), the thrombin receptor‐activating peptide TRAP‐6 (5 and 20 μM), the thromboxane A2 mimetic U‐46619 (1 μM) and collagen (20 and 50 μg ml−1) but not by SPC (up to 20 μM).
SPC concentration‐dependently (IC50 approximately 1–10 μM) inhibited activation of washed human platelets in response to all of the above agonists, with almost complete inhibition occurring at 20 μM SPC.
The SPC stereoisomers, D‐erythro SPC and L‐threo SPC, exhibited similar concentration–response curves in inhibiting 20 μM ADP‐induced platelet aggregation, suggesting that SPC did not act via specific lysophospholipid receptors.
Although SPC slightly activated platelet protein kinase A (as assessed by VASP phosphorylation), this effect could not explain the marked platelet inhibition. Possible protein kinase C inhibition also did not explain the inhibition of platelet activation by SPC. On the other hand, SPC suppressed agonist‐induced Ca2+ mobilization and phospholipase C stimulation.
These results indicate that the lysophospholipid SPC is an effective inhibitor of human platelet activation, apparently primarily by uncoupling agonist‐activated receptors from their effectors.

British Journal of Pharmacology (2003) 138, 435–444. doi:10.1038/sj.bjp.0705063
Interleukin‐1β inhibits ATP‐induced protein kinase B activation in renal mesangial cells by two different mechanisms: the involvement of nitric oxide and ceramide
Authors: Rölz Waltraud , Xin Cuiyan , Ren Shuyu , Pfeilschifter Josef , Huwiler Andrea 
Published: February 2003

Extracellular nucleotides, like ATP and UTP, have been shown to activate the protein kinase B (PKB) pathway in mesangial cells. In this study we report that the pro‐inflammatory cytokine interleukin‐1β (IL‐1β) inhibits ATP‐induced PKB activation.
Pretreatment of mesangial cells with IL‐1β leads to a time‐dependent decrease of ATP‐induced PKB phosphorylation. Maximal inhibition is seen after 6 h of pretreatment. Incubating cells with IL‐1β in the presence of the NO synthase inhibitor, N‐monomethyl‐L‐arginine (L‐NMMA), reversed the IL‐1β inhibition of PKB activity. A similar decrease in ATP‐evoked PKB activation is obtained when cells were pretreated with the nitric oxide (NO) donor, (Z)‐1‐[2‐Aminoethyl)‐N‐(2‐ammonioethyl)amino]diazen‐1‐ium‐1,2‐diolate (Deta‐NO), but not with the cell‐permeable cGMP analogue, 8‐bromo‐cGMP.
The NO‐ and IL‐1β‐mediated delayed inhibition of PKB activity is completely reversed by the phosphatase inhibitor calyculin A, but not by ocadaic acid, suggesting that NO upregulates a protein phosphatase activity, which most probably belongs to the group of protein phosphatases type 1.
In addition, IL‐1β also triggers a short‐term and transient inhibitory effect on ATP‐induced PKB activation which is maximal after 2–5 min of pre‐incubation with IL‐1β. This effect occurs independently of NO generation, because no NO synthase is expressed at that time, and consequently, L‐NMMA does not reverse the effect. Rather an involvement of the sphingolipid ceramide is likely, since IL‐1β triggers rapid ceramide formation and incubation of cells with the cell‐permeable C6‐ceramide blocked ATP‐induced PKB phosphorylation.
In summary, our data show that IL‐1β exerts both short‐term and long‐term inhibitory effects on ATP‐stimulated PKB activation, the short‐term effect probably involves ceramide formation, whereas the long‐term effect is due to inducible NO synthase induction and subsequent NO formation. These results reveal a further facet in the mechanisms of ceramide‐ and NO‐induced cell death, i.e. by turning off the survival signal elicited by PKB.

British Journal of Pharmacology (2003) 138, 461–468. doi:10.1038/sj.bjp.0705064
A Sociocultural Approach to Exclusion
Authors: Sellman Edward , Bedward Julie , Cole Ted , Daniels Harry 
Published: January 2003

ABSTRACTThis essay review presents an overview of the issues surrounding young people and exclusion, with a focus on the formal procedure of permanent exclusion from school. In so doing, recent literature on the issues is critiqued amongst wider reading. It is suggested that theorisation of the processes of exclusion cannot be done at any one level of analysis. A sociocultural approach requires attention to analysis at individual, cultural, historical and institutional levels.Book reviewed in this article:Inclusive Education: policy, contexts and comparative perspectivesFelicityArmstrong, DerrickArmstrong& LenBarton(Eds)Why Pick On Me? School Exclusion and Black YouthMaudBlairChallenges to School ExclusionNevilleHarris, KarenEden& AnnBlairTackling Disaffection and Social Exclusion: education perspectives and policiesAnnetteHayton(Ed.)Defying Disaffection: how schools are winning the hearts and minds of reluctant studentsRevaKleinAlternatives to Exclusion from SchoolPamelaMunn, GwyneddLloyd& MairiAnnCullenEducation, Exclusion and CitizenshipCarlParsonsExperiencing ExclusionEvaPomeroy
Susceptibility patterns of bacteria causing community-acquired respiratory infections in Spain: the SAUCE project
Authors:   the Spanish Surveillance Group for Respiratory Pathogens, García-de-Lomas J. , García-Rey C. , López L. , Gimeno C. 
Published: January 2003

Abstract
Multicentre surveillance is essential in order to monitor the prevalence of certain resistance phenotypes and to identify rapidly the emergence of new ones. However, many surveillance studies are based either on a relatively small number of isolates from a single country, or on a large number of isolates from many different countries and so are not equally meaningful. Extensive national multicentre surveillance would provide a more reliable strategy for assessing the extent of antimicrobial resistance in individual countries. This article describes Spanish experience with the surveillance network SAUCE, and summarizes the main results on antimicrobial resistance in the three key bacterial pathogens involved in community-acquired respiratory tract infections in Spain: Streptococcus pneumoniae , Haemophilus influenzae and Streptococcus pyogenes .
Nasopharyngeal carriage of Streptococcus pneumoniae: a review of the potential role of pharmacokinetics and pharmacodynamics
Authors: Wise R. 
Published: January 2003

Abstract
Much antibiotic prescribing is based upon irrational practice rather than scientific principles. The advent and the better understanding of the pharmacokinetics and pharmacodynamics of antimicrobials are slowly leading to a change whereby antibiotics are prescribed with a better rationale. The fundamental understanding of the pharmacokinetics of the antimicrobial, for example how well it is absorbed, metabolized, distributed and eliminated from the body, should lead to an appreciation of the correct dosing interval. Pharmacodynamic factors, in particular, appreciation of the MIC of an antimicrobial for an infecting pathogen and whether time-independent or -dependent killing occurs, will also have a profound influence upon how an antimicrobial is used. This review attempts to consider these features as they apply to nasopharyngeal carriage of Streptococcus pneumoniae . The reason for the dosing and dosing frequency of a number of agents is discussed and an attempt is made to point the way to more judicious antibiotic prescribing so as to maximize clinical efficacy yet minimize the possibility of resistance emerging during therapy.
Twinning in natural melilite simulating a fivefold superstructure
Authors: Bindi Luca , Rees Leigh H. , Bonazzi Paola 
Published: January 2003

Additional reflections seemingly leading to a tetragonal fivefold supercell have been observed in a number of melilites. A careful examination of the collected intensity data reveals that this feature is due to the coexistence of two twin domains related by a (1\bar20) twin plane. Reflections of the first domain (I) with h_{\rm b}^2+k_{\rm b}^2=5n overlap those of the second domain (II) when both the following additional conditions are verified: −h
b + 2k
b = 5n and 2h
b + k
b = 5n. Indices of the superimposed reflections are h
b,I k
b,I l
b,I for the first domain, and h
b,II = \textstyle{3\over5}\,h
b,I + \textstyle{4\over5}\,k
b,I, k
b,II = \textstyle{4\over5}\,h
b,I − \textstyle{3\over5}\,k
b,I, l
b,II = l
b,I for the second domain. The non-crystallographic pseudosymmetry in the melilite structure is discussed.
Mechanism of Reduced T-Cell Effector Functions and Class-Switched Antibody Responses to Herpes Simplex Virus Type 2 in the Absence of B7 Costimulation
Authors: Thebeau Lydia G. , Morrison Lynda A. 
Published: January 2003

ABSTRACTT-cell costimulation molecules B7-1 and B7-2 play an important role in activation of T cells to cytolytic effector function and production of cytokines. Interaction with B7 also causes T cells to upregulate surface molecules, such as CD40L, that effectively stimulate antibody responses in conjunction with cytokines. We have shown that mice lacking both B7-1 and B7-2 (B7KO mice), when infected intravaginally with virulent herpes simplex virus type 2 (HSV-2), developed more severe disease and higher mortality than their wild-type counterparts. We have now investigated the effects of B7 costimulation deficiency on induction of immune responses to HSV-2 infection of the genital tract. Fewer gamma interferon (IFN-γ)-producing T cells were present in the genital lymph nodes of B7KO mice compared to wild-type mice, either acutely after primary infection or in recall responses. Less IFN-γ and especially interleukin-10 were produced by B7KO mice, and cytolytic T-lymphocyte activity was also attenuated. Reduced expression of CD25 on CD4+T cells after infection of B7KO mice was consistent with deficits in T-cell activation to effector functions. Although HSV-specific immunoglobulin M (IgM) titers were comparable for both B7KO mice and wild-type mice, B7KO mice had significant deficits in HSV-specific serum IgG responses, with markedly reduced levels of IgG2a and IgG1. In addition, significantly less IgG was detected in the vaginal secretions of B7KO mice than in those from wild-type mice. CD4+T-cell expression of CD40L was depressed in B7KO mice in vivo and in vitro. Together with reduced cytokine production, these results suggest a mechanism for decreased IgG class switching or production. Thus, in the absence of B7 costimulation, naïve T cells fail to undergo proper activation in response to HSV-2, which limits T-cell cytokine production, cytotoxic T lymphocyte activity, and provision of help for class-switched antibody responses.