bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of femoral perfusion in a non‐traumatic rabbit osteonecrosis model with T2*‐weighted dynamic MRI
Authors: Tsuji Takashi , Sugano Nobuhiko , Sakai Takashi , Yoshikawa Hideki
Published: February 2003

We evaluated femoral perfusion in a non‐traumatic rabbit serum sickness osteonecrosis (ON) model, using serial repetitive T2*‐weighted (T2*W) dynamic magnetic resonance imaging (MRI) and investigated prediction of ON occurrence in early stages, comparing T2*W dynamic MRI with non‐enhanced (T2‐, T1‐ and fat suppression T1‐weighted) and contrast‐enhanced MRI. Early microcirculatory injury or necrotic lesion was detected in 0% of femora (extravasation, 0/6) at 72 h, 33% (necrotic, 4/12) at 1 week and 100% (necrotic, 14/14) at 3 weeks using non‐enhanced MRI, and in 67% of femora (extravasation, 4/6) at 72 h, 58% (necrotic, 7/12) at 1 week and 100% (necrotic, 14/14) at 3 weeks using contrast‐enhanced MRI. In contrast, microcirculatory injury or necrotic lesion was detected in 83% of femora (extravasation, 5/6) at 72 h, 92% (necrotic, 11/12) at 1 week and 100% (necrotic, 14/14) at 3 weeks using T2*W dynamic MRI as no transient decrease or less marked transient decrease in signal intensity of regions of interest (ROIs), compared to normal femora, which showed a clear transient decrease in signal intensity of ROIs. These results indicate that T2*W dynamic MRI with optimal imaging parameters and a dose of contrast agent is the most sensitive of these three MRI methods and may be clinically useful for evaluating femoral perfusion in artery phase and predicting ON occurrence.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
PMMA particles and pressure—a study of the osteolytic properties of two agents proposed to cause prosthetic loosening
Authors: Skoglund Björn , Aspenberg Per
Published: February 2003

Amongst the wear debris particles implicated in the particle hypothesis for prosthetic loosening are polymethylmethacrylate (PMMA), and particularly PMMA with barium sulphate contrast agent. Another suggested cause for loosening is hydrostatic pressure. PMMA particles were combined with hydrostatic pressure in a study to investigate whether there could be a synergistic or additive effect between these two factors. Titanium plates were fastened onto tibiae of 59 rats. After osseointegration, PMMA particles with barium sulphate were administered to the bone‐implant interface. Further, PMMA particles were introduced into a previously published model for hydrostatic pressure induced osteolysis. There was measurable resorption in response to the PMMA particles but no additive or synergistic effect from introducing particles to the pressure model, and the effect of pressure was far greater than that of particles. These results suggest that, whereas particles can be shown to elicit an osteolytic response, the much less studied osteolytic effects of pressure could be far more important.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Four‐year study of cobalt and chromium blood levels in patients managed with two different metal‐on‐metal total hip replacements
Authors: Lhotka Christian , Szekeres Thomas , Steffan Ilse , Zhuber Klaus , Zweymüller Karl
Published: February 2003

Background: Metal‐on‐metal total hip prostheses will produce a certain amount of wear debris. This results in increased whole‐blood metal levels, which may cause adverse effects. It is not known to what extent the problem has been overcome by advances in alloy technology.

Methods: In 259 patients who with total hip replacement, blood cobalt and chromium concentrations were measured with atomic absorption spectrophotometry over a period of four years after arthroplasty. Of the patients enrolled in the study, 131 had been managed with a METASUL® cobalt‐chromium alloy metal‐on‐metal bearing combination, while 128 had been given a SIKOMET®‐SM21® cobalt‐chromium alloy metal‐on‐metal combination. The control group consisted of 31 age‐ and gender‐matched subjects.

Results: Compared with the controls, all the patients had higher cobalt and chromium levels. Cobalt concentrations were up to 50 times higher, while chromium concentrations were up to 100 times higher.

Conclusions: Both systems showed evidence, in the whole‐blood samples, of wear debris production by the implants. Therefore, patients managed with metal‐on‐metal bearing combinations should be carefully monitored in order to ensure that any local or systemic complications are detected early on.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The use of intra‐articular Na‐hyaluronate as a potential chondroprotective device in experimentally induced acute articular cartilage injury and repair in rabbits
Authors: Williams James M. , Rayan Vineeta , Sumner D. Rick , Thonar Eugene J.‐M. A.
Published: February 2003

Objective: This study examined if viscosupplementation from intra‐articular administration of a commercially available form of hyaluronan (HA) could promote the restoration of proteoglycan (PG) depletion induced by chymopapain and then if the repair could be maintained once HA treatment was discontinued.

Methods: Animals received cartilage injury with intra‐articular chymopapain (2.0 mg) followed by weekly treatment with intra‐articular HA. HA treated animals were compared to injured animals with no treatment, contralateral untreated joints and joints from normal controls. The effect of intra‐articular HA alone on articular cartilage was also examined.

Results: Serum keratan sulfate levels confirmed degradation of the cartilage PGs in the chymopapain‐injected knees. Intra‐articular chymopapain resulted in marked loss of PGs. There were no significant differences among the control groups (untreated control, HA/800 treatment only). HA treatment did not affect the loss of PGs caused by chymopapain after 42 days. However, in animals receiving chymopapain injury followed by weekly HA treatment for 42 days and then 42 days of free cage activity without HA, cartilage PG contents were significantly increased. Intra‐articular HA alone had no effect on the articular cartilage.

Conclusion: The results in the present study suggest a potential protective effect of HA on chymopapain‐induced acute articular cartilage injury in rabbits that, in time, permits damaged cartilage to resynthesize matrix PGs after the HA treatment is discontinued.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Mesencephalic innervation of the vibrissal follicle–sinus complex in the mouse embryo
Authors: Croydon Andrew T. , Millar Brian J. , Linden Roger W.A. , Maden Malcolm
Published: February 2003

Peripheral projections of neurones whose cell bodies lie in the mesencephalic nucleus of the fifth cranial nerve, situated between the central grey and mesencephalic reticular formation, were studied in mouse embryos aged between day 9 and 15 and in postnatal day 1 mice. Nonspecific neural antibody staining allowed visualisation of the developing cranial nerves, in particular the descending mesencephalic tract. This facilitated successful dissection of the descending mesencephalic tract and trigeminal ganglion in the heads of fresh mouse embryos and postnatal mice. The fluorescent dye, 1,1′‐dioctadecyl‐3,3,3′,3′‐tetramethylindocarbocyanine perchlorate (DiI), was injected into the descending mesencephalic tract in mouse embryos aged 12.5, 13.5 and 15 days of gestation and also into postnatal day 1 mice. Following a period of incubation, 100 μm sections were viewed under visible light and episcopic fluorescence. Mesencephalic neurones were observed to pass superiorly over the trigeminal ganglion and enter the maxillary division to innervate vibrissal follicle–sinus complexes, whilst none was observed innervating mandibular and maxillary intraoral structures. There was no fluorescent labelling in non‐DiI injected control specimens.

Using a highly specific neuronal tracer, this study shows that mesencephalic neurones in the periphery project exclusively to follicle–sinus complexes in the developing mouse embryo and remain at least until postnatal day 1. These observations, contrary to those made in other animals, indicate a species specificity of mesencephalic peripheral projections.
Differential effects of prepubertal chronic oestrogen treatment on the synthesis of noradrenaline in uterine myometrial and perivascular sympathetic nerves
Authors: Brauer M.M. , Llodrá J. , Scorza M.C. , Chávez R. , Burnstock G. , Thrasivoulu C. , Cowen T.
Published: February 2003

Previous studies have shown that chronic administration of oestrogen to prepubertal rats reduces the total content of noradrenaline in the uterine horn, abolishes myometrial noradrenergic innervation and reduces noradrenaline‐fluorescence intensity of intrauterine perivascular nerve fibres. The mechanisms underlying these changes are not known. In the present study we have analysed the effects of prepubertal chronic oestrogen treatment on the synthesis of noradrenaline in the rat uterine sympathetic nerves using biochemical and immunohistochemical approaches. Tyrosine hydroxylase activity was evaluated biochemically, by measuring the in vivo accumulation of dihydroxyphenylalanine (DOPA) in the presence of a DOPA‐decarboxylase inhibitor. In addition, nerve fibres were visualised immunohistochemically using antibodies against tyrosine hydroxylase (TH), dopamine‐β‐hydroxylase (DβH) and the general marker protein gene product 9.5 (PGP 9.5). After chronic oestrogen treatment, the total content of noradrenaline of the uterine horn was reduced, whereas the total content of DOPA was increased. In controls, TH‐immunoreactive, DβH‐immunoreactive and PGP 9.5‐immunoreactive nerve fibres were distributed in both the circular and longitudinal myometrial layers and in the blood vessels of the intra‐myometrial region. After chronic oestrogen treatment the only fibres recognised by the three antibodies were those associated with the blood vessels, but no myometrial‐associated fibres could be recognised. These results suggest that noradrenaline synthesis is selectively reduced in myometrial‐associated uterine sympathetic nerves, but is preserved in perivascular sympathetic nerves. The increased DOPA levels measured after chronic exposure to oestrogen was interpreted as the consequence of the substantial increase in size and number of blood vessels observed in the uterus of oestrogen‐treated animals. A possible neurodegenerative effect of oestrogen on myometrial sympathetic fibres is discussed.
Distribution of BDNF, NT‐3 and NT‐4 in the developing auditory brainstem
Authors: Hafidi Aziz
Published: February 2003

This 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
Architects' Conceptions of the Human Body
Authors: Imrie Rob
Published: January 2003

In this paper I develop the contention that architects rarely relate their design conceptions to the human body and its multiple forms of embodiment. Where the body is conceived of, it is usually in terms of a conception of the ‘normal body’, or a body characterised by geometrical proportions arranged around precise Cartesian dimensions. I describe and evaluate the content and implications of architects' conceptions of the body and embodiment, and consider the possibilities for, and problems in, challenging the dominance of bodily reductive conceptions in architecture.
Baudrillard's Nonrepresentational Theory: Burn the Signs and Journey without Maps
Authors: Smith Richard G
Published: January 2003

Can we burn the signs and journey without maps? In other words, can we travel from representational theories, through Baudrillard's critique of representation, to forms of theory that are somehow nonrepresentational? In this paper I hijack and go beyond Baudrillard's concepts of the precession and orders of simulacra to illustrate two main things: first, how the history of geographical thought has been one of representational theory, where there was seen to be a relationship, and then commutation, of theory and the real world; second, how representational theories are perhaps out of tune, unable to explain adequately, or change, our digital and commodity—sign soaked culture of simulacra, simulations, and reproductions. Overall, I attempt to show clearly how, through his poststructuralist critique of representation, Baudrillard is challenging us to rethink theory as doubly nonrepresentational.
Spectral Returns of Domesticity
Authors: Baydar Gülsüm
Published: January 2003

This is a study of the link between the house and the city, based on a close reading of three historical statements from Western urban theory by Leone Batisti Alberti, Le Corbusier, and Paul Virilio. Sexualized metaphors of the house as the feminine, private realm and the city as the masculine, public realm proliferate in the modern period. However, rather than conforming to this conventional opposition, these three authors define the city in terms of the house. Their statements provide a curious link across temporal and geographical boundaries, with significant theoretical implications. In all three cases both the feminine figure and themes of loss and death underlie the desire to project the ideal city. In this paper I argue that these themes intertwine in complicated ways to assert urban identification in terms of a masculine desire of total control and mastery by silencing the feminine figure.
The Region in the Boot: Mobilising Lone Subjects and Multiple Objects
Authors: Laurier Eric , Philo Chris
Published: January 2003

Company regions are forms of space busy with the sorting and distributing of objects from one location to another. We argue here, in sympathy with actor-network theory and nonrepresentational theory, that space is formulated by and formulative of its objects in mutually elaborating occasions and chains of action. The handling of objects that produces regions requires not simply that they are put in a place, but that they are put in a relevant place. Finding the relevant where is bound to the relevant when in the sense that the uses of objects are bound to sequential considerations of the kind: what happens next? Regions are cultural, social, political, and sometimes theoretical entities for economists, geographers, and other professional social scientists, but they are also topics of concern to regional managers of business companies, who are unavoidably and pervasively involved in the practical activities of spatial organisation. In this paper we are pursuing the situated replication of sociospatial technologies, or, in other words, how the same thing is done over and over again by local employees, with both the materials that they have at hand and the contingent circumstances in which they locate themselves. In pursuing our analysis we follow one particular mobile worker as she goes about her daily work of managing her region. What we attempt to excavate from our ethnographic material is the order that is endogenous to those activities. It is an everyday order that does not turn on spectacular technologies but turns, rather, on mundane ones such as stacking cardboard boxes, arranging items in the boot of a car, and driving around a city.
Last of the ‘Real Geordies’? White Masculinities and the Subcultural Response to Deindustrialisation
Authors: Nayak Anoop
Published: January 2003

In this historical ethnography I investigate how a group of young white men are negotiating the transition to a postindustrial society. Their insular, subcultural practices are seen as complex, materially orchestrated responses to the ‘new times’ of the changing local—global economy. In the context of deindustrialisation I consider how a white, industrial masculinity could be recuperated in the field of consumption, notably through embodied rituals of football support, drinking, and going out. I conclude by arguing that geographers need to be more attentive to local nuances and regional identities in their theoretical analysis of economic restructuring and globalisation.
‘Putting on a Face’: Sartre, Goffman, and Agoraphobic Anxiety in Social Space
Authors: Davidson Joyce
Published: January 2003

In this paper I attempt a hermeneutics of agoraphobic experience, presenting a reading of sufferers' accounts of the social and spatial phenomenology of this disorder in terms of managing existential anxieties. I seek to combine the philosophical insights of Sartre's account of ‘anguish’ with Goffman's sociotheoretical account of the individual's employment of techniques of ‘front management’ and ‘self-presentation’. Such techniques might, I argue, be regarded as a form of coping mechanism for dealing with the anxieties of social existence, especially those stemming from what Sartre terms the ‘look’ of Others. Agoraphobics' testimonies illustrate their difficulties in successfully deploying such techniques in the face of the anxieties they experience in social spaces. Interpreting agoraphobic experiences in this way adds a sociospatial theoretical dimension to existing accounts of the disorder, accounts that are currently of a predominantly psychological nature.
Lower blood glucose, hyperglucagonemia, and pancreatic α cell hyperplasia in glucagon receptor knockout mice
Authors: Gelling R. W. , Du X. Q. , Dichmann D. S. , Rømer J. , Huang H. , Cui L. , Obici S. , Tang B. , Holst J. J. , Fledelius C. , Johansen P. B. , Rossetti L. , Jelicks L. A. , Serup P. , Nishimura E. , Charron M. J.
Published: February 2003

Glucagon, the counter-regulatory hormone to insulin, is secreted from pancreatic α cells in response to low blood glucose. To examine the role of glucagon in glucose homeostasis, mice were generated with a null mutation of the glucagon receptor (Gcgr
−/−
). These mice display lower blood glucose levels throughout the day and improved glucose tolerance but similar insulin levels compared with control animals. Gcgr
−/−
mice displayed supraphysiological glucagon levels associated with postnatal enlargement of the pancreas and hyperplasia of islets due predominantly to α cell, and to a lesser extent, δ cell proliferation. In addition, increased proglucagon expression and processing resulted in increased pancreatic glucogen-like peptide 1 (GLP-1) (1–37) and GLP-1 amide (1–36 amide) content and a 3- to 10-fold increase in circulating GLP-1 amide. Gcgr
−/−
mice also displayed reduced adiposity and leptin levels but normal body weight, food intake, and energy expenditure. These data indicate that glucagon is essential for maintenance of normal glycemia and postnatal regulation of islet and α and δ cell numbers. Furthermore, the lean phenotype of Gcgr
−/−
mice suggests glucagon action may be involved in the regulation of whole body composition.
Involvement of bone morphogenetic protein 4 (BMP-4) in pituitary prolactinoma pathogenesis through a Smad/estrogen receptor crosstalk
Authors: Páez-Pereda Marcelo , Giacomini Damiana , Refojo Damian , Nagashima Alberto Carbia , Hopfner Ursula , Grübler Yvonne , Chervin Alberto , Goldberg Victoria , Goya Rodolfo , Hentges Shane T. , Low Malcolm J. , Holsboer Florian , Stalla Günter K. , Arzt Eduardo
Published: February 2003

Pituitary tumor development involves clonal expansion stimulated by hormones and growth factors/cytokines. Using mRNA differential display, we found that the bone morphogenetic protein (BMP) inhibitor noggin is down-regulated in prolactinomas from dopamine D2-receptor-deficient mice. BMP-4 is overexpressed in prolactinomas taken from dopamine D2-receptor-deficient female mice, but expression of the highly homologous BMP-2 does not differ in normal pituitary tissue and prolactinomas. BMP-4 is overexpressed in other prolactinoma models, including estradiol-induced rat prolactinomas and human prolactinomas, compared with normal tissue and other pituitary adenoma types (Western blot analysis of 48 tumors). BMP-4 stimulates, and noggin blocks, cell proliferation and the expression of c-Myc in human prolactinomas, whereas BMP-4 has no action in other human pituitary tumors. GH3 cells stably transfected with a dominant negative of Smad4 (Smad4dn; a BMP signal cotransducer) or noggin have reduced tumorigenicity in nude mice. Tumor growth recovered
in vivo
when the Smad4dn expression was lost, proving that BMP-4/Smad4 are involved in tumor development
in vivo
. BMP-4 and estrogens act through overlapping intracellular signaling mechanisms on GH3 cell proliferation and c-myc expression: they had additive effects at low concentrations but not at saturating doses, and their action was inhibited by blocking either pathway with the reciprocal antagonist (i.e., BMP-4 with ICI 182780 or 17β-estradiol with Smad4dn). Furthermore, coimmunoprecipitation studies demonstrate that under BMP-4 stimulation Smad4 and Smad1 physically interact with the estrogen receptor. This previously undescribed prolactinoma pathogenesis mechanism may participate in tumorigenicity in other cells where estrogens and the type β transforming growth factor family have important roles.
A segmental nearest neighbor normalization and gene identification method gives superior results for DNA-array analysis
Authors: Yang He , Haddad Hadar , Tomas Christopher , Alsaker Keith , Papoutsakis E. Terry
Published: February 2003

An intuitive normalization and gene identification method is proposed. After segmentation of the entire expression range into intensity intervals, the mean and standard deviation of the logarithm of expression ratios are calculated for each interval using the nearest neighbor genes. Genes with high differential expression are excluded from these calculations. For glass arrays, normalization is performed for each interval by using the mean of the logarithm of expression ratios in the interval. For nylon/plastic membranes, the average of the means of the logarithm of ratios across the intervals of higher intensities is used for normalization. Compared with other normalization methods, this method delivered the smallest normalization errors for 42 nylon/plastic arrays used to analyze cultured T cells and 22
Clostridium acetobutylicum
glass arrays. For identifying differentially expressed genes, upper and lower boundaries are constructed for each interval by using the standard deviation of the expression ratio logarithms. When a
C. acetobutylicum
pSOL1 megaplasmid-deficient strain M5 was used, this method identified more “down-regulated” pSOL1 genes with fewer misidentifications in a comparative array analysis of M5 versus the parent strain. A comparison of quantitative RT-PCR results with different gene identification methods indicates that the proposed method is superior to other methods.
Reduction of cholera in Bangladeshi villages by simple filtration
Authors: Colwell Rita R. , Huq Anwar , Islam M. Sirajul , Aziz K. M. A. , Yunus M. , Khan N. Huda , Mahmud A. , Sack R. Bradley , Nair G. B. , Chakraborty J. , Sack David A. , Russek-Cohen E.
Published: February 2003

Based on results of ecological studies demonstrating that
Vibrio cholerae
, the etiological agent of epidemic cholera, is commensal to zooplankton, notably copepods, a simple filtration procedure was developed whereby zooplankton, most phytoplankton, and particulates >20 μm were removed from water before use. Effective deployment of this filtration procedure, from September 1999 through July 2002 in 65 villages of rural Bangladesh, of which the total population for the entire study comprised ≈133,000 individuals, yielded a 48% reduction in cholera (
P
< 0.005) compared with the control.
Placental mammal diversification and the Cretaceous–Tertiary boundary
Authors: Springer Mark S. , Murphy William J. , Eizirik Eduardo , O'Brien Stephen J.
Published: February 2003

Competing hypotheses for the timing of the placental mammal radiation focus on whether extant placental orders originated and diversified before or after the Cretaceous-Tertiary (K/T) boundary. Molecular studies that have addressed this issue suffer from single calibration points, unwarranted assumptions about the molecular clock, and/or taxon sampling that lacks representatives of all placental orders. We investigated this problem using the largest available molecular data set for placental mammals, which includes segments of 19 nuclear and three mitochondrial genes for representatives of all extant placental orders. We used the Thorne/Kishino method, which permits simultaneous constraints from the fossil record and allows rates of molecular evolution to vary on different branches of a phylogenetic tree. Analyses that used different sets of fossil constraints, different priors for the base of Placentalia, and different data partitions all support interordinal divergences in the Cretaceous followed by intraordinal diversification mostly after the K/T boundary. Four placental orders show intraordinal diversification that predates the K/T boundary, but only by an average of 10 million years. In contrast to some molecular studies that date the rat–mouse split as old as 46 million years, our results show improved agreement with the fossil record and place this split at 16–23 million years. To test the hypothesis that molecular estimates of Cretaceous divergence times are an artifact of increased body size subsequent to the K/T boundary, we also performed analyses with a “K/T body size” taxon set. In these analyses, interordinal splits remained in the Cretaceous.
Identification of an endogenous ligand that activates pregnane X receptor-mediated sterol clearance
Authors: Dussault Isabelle , Yoo Hye-Dong , Lin Min , Wang Eric , Fan Ming , Batta Ashok K. , Salen Gerald , Erickson Sandra K. , Forman Barry M.
Published: February 2003

The nuclear receptor PXR (pregnane X receptor) is a broad-specificity sensor that recognizes a wide variety of synthetic drugs and xenobiotic agents. On activation by these compounds, PXR coordinately induces a network of transporters, cytochrome P450 enzymes, and other genes that effectively clear xenobiotics from the liver and intestine. Like PXR, the majority of its target genes also possess a broad specificity for exogenous compounds. Thus, PXR is both a sensor and effector in a well integrated and generalized pathway for chemical immunity. Although it is clear that PXR responds to numerous foreign compounds, it is unclear whether it possesses an endogenous ligand. To address this issue, we noted that there is substantial overlap in the substrate specificities of PXR and its critical
CYP3A
target gene. This prompted us to ask whether endogenous CYP3A substrates also serve as PXR ligands. We demonstrate that 5β-cholestane-3α,7α,12α-triol (triol), a cholesterol-derived CYP3A substrate, is a potent PXR agonist that effectively induces
cyp3a
expression in mice. This defines a critical salvage pathway that can be autoinduced to minimize triol accumulation. In contrast, triol can accumulate to very high levels in humans, and unlike mice, these people develop the severe clinical manifestations of cerebrotendinous xanthomatosis. The reason for these dramatic species differences has remained unclear. We now demonstrate that triol fails to activate human PXR or induce the
CYP3A
-salvage pathway. This explains why humans are more susceptible to sterol accumulation and suggests that synthetic ligands for human PXR could be used to treat cerebrotendinous xanthomatosis and other disorders of cholesterol excess.
Endocannabinoid signaling via cannabinoid receptor 1 is involved in ethanol preference and its age-dependent decline in mice
Authors: Wang Lei , Liu Jie , Harvey-White Judith , Zimmer Andreas , Kunos George
Published: February 2003

Cannabinoids and ethanol can activate the same reward pathways, which could suggest endocannabinoid involvement in the rewarding effects of ethanol. The high ethanol preference of young (6–10 weeks) C57BL/6J mice is reduced by the cannabinoid receptor 1 (CB1) antagonist SR141716A to levels observed in their CB1 knockout littermates or in old (26–48 weeks) wild-type mice, in both of which ethanol preference is unaffected by SR141716A. Similarly, SR141716A inhibits food intake in food-restricted young, but not old, wild-type mice. There are no age-dependent differences in the tissue levels of the endocannabinoids anandamide and 2-arachidonoylglycerol or the density of CB1 in the hypothalamus, limbic forebrain, amygdala, and cerebellum. CB1-stimulated guanosine 5′-[γ-thio]triphosphate (GTP[γS]) binding is selectively reduced in the limbic forebrain of old compared with young wild-type mice. There is no age-dependent difference in Gior Gosubunit protein expression in the limbic forebrain, and the selective reduction in GTP[γS] labeling in tissue from old mice is maintained in a receptor/G protein reconstitution assay by using functional bovine brain G protein. These findings suggest that endocannabinoids acting at CB1 contribute to ethanol preference, and decreased coupling of CB1 to G proteins in the limbic forebrain by mechanisms other than altered receptor or G protein levels may be involved in the age-dependent decline in the appetite for both ethanol and food.
Deficiency of acyl CoA:cholesterol acyltransferase 2 prevents atherosclerosis in apolipoprotein E-deficient mice
Authors: Willner Emily L. , Tow Bryan , Buhman Kimberly K. , Wilson Martha , Sanan David A. , Rudel Lawrence L. , Farese Robert V.
Published: February 2003

Deficiency of acyl CoA:cholesterol acyltransferase 2 (ACAT2) in mice results in a reduction in cholesterol ester synthesis in the small intestine and liver, which in turn limits intestinal cholesterol absorption, hepatic cholesterol gallstone formation, and the accumulation of cholesterol esters in the plasma lipoproteins. Here we examined the contribution of ACAT2-derived cholesterol esters to atherosclerosis by crossing ACAT2-deficient (ACAT2
–/–
) mice with apolipoprotein (apo) E-deficient (ApoE
–/–
) mice, an atherosclerosis-susceptible strain that has impaired apoE-mediated clearance of apoB-containing lipoproteins. ACAT2
–/–
ApoE
–/–
mice and ACAT2
+/+
ApoE
–/–
(control) mice had similar elevations of plasma apoB and total plasma lipids; however, the lipid cores of the apoB-containing lipoproteins in ACAT2
–/–
ApoE
–/–
mice contained primarily triglycerides rather than cholesterol esters. At 30 wk of age, only the control mice had significant atherosclerosis, which was nearly absent in ACAT2
–/–
ApoE
–/–
mice. ACAT2 deficiency in the apoE-deficient background also led to a compensatory increase in the activity of lecithin/cholesterol acyltransferase, the major plasma cholesterol esterification enzyme, which increased high-density lipoprotein cholesterol esters. Our results demonstrate the crucial role of ACAT2-derived cholesterol esters in the development of atherosclerosis in mice and suggest that triglyceride-rich apoB-containing lipoproteins are not as atherogenic as those containing cholesterol esters. Our results also support the rationale of pharmacological inhibition of ACAT2 as a therapy for atherosclerosis.