Role of β3-adrenergic receptors in the action of a tumour lipid mobilizing factor

Induction of lipolysis in murine white adipocytes, and stimulation of adenylate cyclase in adipocyte plasma membranes, by a tumour-produced lipid mobilizing factor, was attenuated by low concentrations (10-7-10-5M) of the specific β3-adrenoceptor antagonist SR59230A. Lipid mobilizing factor (250 nM) produced comparable increases in intracellular cyclic AMP in CHOKI cells transfected with the human β3-adrenoceptor to that obtained with isoprenaline (1 nM). In both cases cyclic AMP production was attenuated by SR59230A confirming that the effect is mediated through a β3-adrenoceptor. A non-linear regression analysis of binding of lipid mobilizing factor to the β3-adrenoceptor showed a high affinity binding site with a Kd value 78±45 nM and a Bmax value (282±1 fmole mg protein-1) comparable with that of other β3-adrenoceptor agonists. These results suggest that lipid mobilizing factor induces lipolysis through binding to a β3-adrenoceptor. © 2002 The Cancer Research Campaign.

Solidarity and power in German : language as political action : a contribution to the socio-cultural history of the German language

Germany's latest attempt at unification raises again the question of German nationhood and nationality. The present study examines the links between the development of the German language and the political history of Germany, principally in the nineteenth and twentieth centuries. By examining the role of language in the establishment and exercise of political power and in the creation of national and group solidarity in Germany, the study both provides insights into the nature of language as political action and contributes to the socio-cultural history of the German language. The language-theoretical hypothesis on which the study is based sees language as a central factor in political action, and opposes the notion that language is a reflection of underlying political 'realities' which exist independently of language. Language is viewed as language-in-text which performs identifiable functions. Following Leech, five functions are distinguished, two of which (the regulative and the phatic) are regarded as central to political processes. The phatic function is tested against the role of the German language as a creator and symbol of national identity, with particular attention being paid to concepts of the 'purity' of the language. The regulative function (under which a persuasive function is also subsumed) is illustrated using the examples of German fascist discourse and selected cases from German history post-1945. In addition, the interactions are examined between language change and socio-economic change by postulating that language change is both a condition and consequence of socio-economic change, in that socio-economic change both requires and conditions changes in the communicative environment. Finally, three politocolinguistic case studies from the eight and ninth decades of the twentieth century are introduced in order to demonstrate specific ways in which language has been deployed in an attempt to create political realities, thus verifying the initial hypothesis of the centrality of language to the political process.

The mode of action of a lipid mobilising factor in cancer cachexia

Cachexia is characterised by a progressive weight loss due to depletion of both skeletal muscle and adipose tissue. The loss of adipose tissue is due to the production of a tumour-derived lipid mobilising factor (LMF), which has been shown to directly induce lipolysis in isolated epididymal murine white adipocytes. The administration of LMF to a non-tumour bearing mice produced a rapid weight loss, with a specific reduction in carcass lipid with also some redistribution of lipid with the accumulation of lipid in the liver. There was also up-regulation of uncoupling protein-1 and -2 mRNA and protein expression in brown adipose tissue, suggesting that an adaptive process occurs due to increased energy mobilisation. There was also up-regulation of UCP-2 in the livers of LMF treated mice, suggesting a protective mechanism to the build up of lipid in the livers, which would produce free radical by-products. LMF was also shown to stimulate cyclic AMP production in CHO-K1 cells transfected with human -3 adrenergic receptors and inhibited by the -β3 antagonist SR59230A. LMF binding was also inhibited by SR59230A in isolated receptors. This suggests that LMF mediates its effects through a β3 adrenergic receptor. There were also changes in glucose and fatty acid uptake in LMF treated mice, which suggests metabolic changes are occurring. The study suggests that a tumour derived lipolytic factor acts through the 3 adrenoceptor producing effects on lipid mobilisation, energy expenditure and glucose metabolism.

Effect of dopamine on synchronous neuronal oscillations in the globus pallidus-subthalamic nucleus network

Changes in the pattern of activity of neurones within the basal ganglia are relevant in the pathophysiology and symptoms of Parkinson’s disease. The globus pallidus (GP) – subthalamic nucleus (STN) network has been proposed to form a pacemaker driving regenerative synchronous bursting activity. In order to test whether this activity can be sustained in vitro a 20o parasagittal slice of mouse midbrain was developed which preserved functional connectivity between the STN and GP. Mouse STN and GP cells were characterised electrophysiologically by the presence or absence of a voltage sag in response to hyperpolarising current steps indicative of Ih and the presence of rebound depolarisations. The presence of evoked and spontaneous post-synaptic GABA and glutamatergic currents indicated functional connectivity between the STN and GP. In control slices, STN cells fired action potentials at a regular rate, activity which was unaffected by bath application of the GABAA receptor antagonist picrotoxin (50 μM) or the glutamate receptor antagonist CNQX (10 μM). Paired extracellular recordings of STN cells showed uncorrelated firing. Oscillatory burst activity was induced pharmacologically using the glutamate receptor agonist, NMDA (20 μM), in combination with the potassium channel blocker apamin (50 -100 nM). The burst activity was unaffected by bath application of picrotoxin or CNQX while paired STN recordings showed uncorrelated activity indicating that the activity is not produced by the neuronal network. Thus, no regenerative activity is evident in this mouse brain preparation, either in control slices or when bursting is pharmacologically induced, suggesting the requirement of other afferent inputs that are not present in the slice. Using single-unit extracellular recording, dopamine (30 μM) produced an excitation of STN cells. This excitation was independent of synaptic transmission and was mimicked by both the Dl-like receptor agonist SKF38393 (10 μM) and the D2-like receptor agonist quinpirole (10 μM). However, the excitation was partially reduced by the D1-like antagonist SCH23390 (2 μM) but not by the D2-like antagonists sulpiride (10 μM) and eticlopride (10 μM). Using whole-recordings, dopamine was shown to induce membrane depolarisation. This depolarisation was caused either by a D1-like receptor mediated increase in a conductance which reversed at -34 mV, consistent with a non-specific cation conductance, or a D2-like receptor mediated decrease in conductance which reversed around -100 mV, consistent with a potassium conductance. Bath application of dopamine altered the pattern of the burst-firing produced by NMDA an apamin towards a more regular pattern. This effect was associated with a decrease in amplitude and ll1crease in frequency of TTX-resistant plateau potentials which underlie the burst activity.

Second messenger pathways in the action of cachectic factors

Cachexia in cancer is characterised by progressive depletion of both adipose tissue stores and skeletal muscle mass. Two catabolic factors produced by cachexia-inducing tumours have the potential for inducing these changes in body composition: (i) proteolysis-inducing factor (PIF) which acts on skeletal muscle to induce both protein degradation and inhibit protein synthesis, (ii) lipid-mobilising factor (LMF), which has been shown to directly induce lipolysis in isolated epididymal murine white adipocytes. Administration of lipid-mobilising factor (LMF) to mice produced a specific reduction in carcass lipid with a tendency to increase non-fat carcass mass. Treatment of murine myoblasts, myotubes and tumour cells with tumour-produced LMF, caused concentration dependent stimulation of protein synthesis, within a 24hr period. It produced an increase in intracellular cyclic AMP levels, which was linearly related to the increase in protein synthesis. The observed effect was attenuated by pretreating cells with the adenylate cyclase inhibitor, MDL12330A and was additive with stimulation produced by forskolin. Both propranolol and a specific 3 adrenergic antagonist SR59230A, significantly reduced the stimulation of protein synthesis induced by LMF. LMF also affected protein degradation in vitro, as demonstrated by a reduction in proteasome activity, a key component of the ubiquitin-dependent proteolytic pathway. These effects were opposite to those produced by PIF which caused both a decrease in the rate of protein synthesis and an elevation on protein breakdown when incubated in vitro.Incubation of LMF with a fat cell line produced alterations in the levels of guanine-nucleotide binding proteins (G proteins). This was also evident in adipocyte plasma membranes isolated from mice bearing the tumour model of cachexia, MAC16 adenocarcinoma and from patients with cancer cachexia. Progression through the cachectic state induced an upregulation of stimulatory G proteins paralleled with a downregulation of inhibitory G proteins. These changes would contribute to the increased lipid mobilisation seen in cancer cachexia.

Production and action of local mediators in the rat gastric mucosa

This study concerns the production and action of the local mediators nitric oxide (NO) and prostaglandin E2 (PGE2) in the rat gastric mucosa. The major objectives were: (i) to determine which mucosal cell type(s) contained NO synthase activity, (ii) to establish the functional role(s) of NO in the gastric mucosa and (iii) to investigate regulation of gastric PGE2 production. Gastric mucosal cells were isolated by pronase digestion coupled with intermittent calcium chelation and were separated by either density-gradient centrifugation or by counterflow elutriation. The distribution of Ca2+ -dependent NO synthase activity, measured via the conversion of [14C]-L-arginine to [14C]-L- citrulline, paralleled the distribution of mucous cells in elutriated fractions. Pre-treatment of rats with lipopolysaccharide caused the induction of Ca2+ -independent NO synthase in the elutriator fractions enriched with mucous cells. Incubation of isolated cells with the NO donor isosorbide dinitrate (ISDN) produced a concentration-dependent increase in the guanosine 3',-5'-cyclic monophosphate (cGMP) content which was accompanied by a concentration-dependent increase in release of immunoreactive mucin. Intragastric administration of ISDN of dibutyryl cGMP in vivo increased the thickness of the mucus layer overlying the gastric mucosa. The NO donor S-nitroso-N-acetylpenicillamine (SNAP) produced a concentration-dependent inhibition (IC50 247 μM) of histamine-stimulated aminopyrine accumulation, a measure of secretory activity, in cell suspensions containing > 80% parietal cells. SNAP increased the cGMP content of the suspension but did not decrease cellular viability, glucose oxidation or adenosine 3',5'-cyclic monophosphate content. The inhibitory effect of SNAP was observed in permeabilised cells stimulated with ATP and was stereospecifically blocked by preincubation with Rp-8-bromoguanosine 3'-5'-monophosphorothioate, which inhibits activation of cGMP-dependent protein kinase. Stimulation of PGE2 release by bradykinin in a low density cell fraction, enriched with parietal cells and devoid of vascular endothelial cells and macrophages, involved a bradykinin B1 receptor. In summary, NO synthase activity is probably present in gastric mucous epithelial cells. NO may promote mucus secretion by elevation of cGMP. NO donors inhibit acid secretion at a specific site and their action may involve cGMP. The bradykinin B1 receptor is involved with PGE2 production in the gastric mucosa.

Organic synthesis and fungicidal activity of oxylipin-based compounds

Previous research has shown that the naturally occurring reactive electrophilic species (RES), 12-oxophytodienoic acid (OPDA), not only serves as a precursor for jasmonic acid but is also a potent antifungal compound. However, both the low amount present in plants and the multistep synthesis required to produce this compound on a scale viable for agrochemical use currently limits its practical value. The aim of this research was to generate a range of molecular mimics of OPDA with a minimum number of synthetic steps and screen for antifungal activity. Synthetic 4-octyl-cyclopentenone containing the cyclopentenone ring and an eight carbon alkyl chain was found to show the highest in vitro antifungal activity against C. herbarum and B. cinerea with minimum inhibition concentration (MIC) of 100-200µM. This indicates that structurally simplified 4-octyl-cyclopentenone can be successfully synthesised to mimic the antifungal activity of OPDA against specific fungal strains. Application of 4-octyl-cyclopentenone could act as surfactant by disrupting and disorganising the lipid membrane non-specifically, resulting in the leakage of potassium ions, which was the proposed mode of action of this compound. However, the sensitivity of fungi to this compound is not correlated to the lipid composition of fungal spores. (E)-2-alkenals were also studied for their antimicrobial activity and (E)-2-undecenal was found to have the highest antimicrobial activity against a range of pathogens. The hydrophilic moiety (the a,ß-unsaturated carbonyl group), common to both (E)-2-undecenal and 4-octyl-cyclentenone is essential to their bioactivity, and the hydrophobic moiety plays an important role in their antimicrobial activities. 4-Octyl-cyclopentenone showed no visible toxicity to the test plant, Arabidopsis thaliana, suggesting that its high antifungal activity against Botrytis and Cladosporium could be exploited for commercialisation as a new generation of agrochemical.

Doing action research in English language teaching:a guide for practitioners

This hands-on, practical guide for ESL/EFL teachers and teacher educators outlines, for those who are new to doing action research, what it is and how it works. Straightforward and reader friendly, it introduces the concepts and offers a step-by-step guide to going through an action research process, including illustrations drawn widely from international contexts. Specifically, the text addresses: •action research and how it differs from other forms of research •the steps involved in developing an action research project •ways of developing a research focus •methods of data collection •approaches to data analysis •making sense of action research for further classroom action. Each chapter includes a variety of pedagogical activities: •Pre-Reading questions ask readers to consider what they already know about the topic •Reflection Points invite readers to think about/discuss what they have read •action points ask readers to carry out action-research tasks based on what they have read •Classroom Voices illustrate aspects of action research from teachers internationally •Summary Points provide a synopsis of the main points in the chapter

Shaping strategic action through the rhetorical construction and exploitation of ambiguity

This paper extends existing understandings of how actors' constructions of ambiguity shape the emergent process of strategic action. We theoretically elaborate the role of rhetoric in exploiting strategic ambiguity, based on analysis of a longitudinal case study of an internationalization strategy within a business school. Our data show that actors use rhetoric to construct three types of strategic ambiguity: protective ambiguity that appeals to common values in order to protect particular interests, invitational ambiguity that appeals to common values in order to invite participation in particular actions, and adaptive ambiguity that enables the temporary adoption of specific values in order to appeal to a particular audience at one point in time. These rhetorical constructions of ambiguity follow a processual pattern that shapes the emergent process of strategic action. Our findings show that (1) the strategic actions that emerge are shaped by the way actors construct and exploit ambiguity, (2) the ambiguity intrinsic to the action is analytically distinct from ambiguity that is constructed and exploited by actors, and (3) ambiguity construction shifts over time to accommodate the emerging pattern of actions.

Dynamic learning as entrepreneurial action in the context of open innovation:an instrumental case from a communities-of-practice perspective

Recent scholarly discussion on open innovation put forward the notion that an organisation's ability to internalise external knowledge and learn from various sources in undertaking new product development is crucial to its competitive performance. Nevertheless, little attention has been paid to how growth-oriented small firms identify and exploit entrepreneurial opportunities (i.e. take entrepreneurial action) related to such development, in an open innovation context, from a social learning perspective. This chapter, based on an instrumental case-firm, demonstrates analytically how learning as entrepreneurial action takes place, drawing on situated learning theory. It is argued that such learning is dynamic in nature and is founded on specific organising principles that foster both inter- and intracommunal learning. © 2012, IGI Global.

5-Hydroxytryptamine induced excitation and inhibition in the subthalamic nucleus:action at 5-HT2C, 5-HT4 and 5-HT1A receptors

Extracellular single-unit recordings in mouse brain slices were used to determine the effect of exogenously applied 5-HT on STN neurones. Recordings were made from 74 STN cells which fired action potentials at a regular rate of 7.19 ± 0.5 Hz. In 61 cells (82%), 5-HT application increased STN neurone firing rate (10 μM, 180 ± 16.8%, n = 35) with an estimated EC 50 of 5.4 μM. The non-specific 5-HT2 receptor agonist α-methyl 5-HT (1-10 μM) mimicked 5-HT induced excitations (15 cells). These excitations were significantly reduced by pre-perfusion with the specific 5-HT2C receptor antagonist RS102221 (500 nM, 9 cells) and the 5HT4 antagonist GR113808 (500 nM, 7 cells). In 6 cells (8%) 5-HT induced biphasic responses where excitation was followed by inhibition, while in 7 cells (9%) inhibition of firing rate was observed alone. Inhibitory responses were reduced by the 5-HT1A antagonist WAY100135 (1 μM, 4 cells). No inhibitory responses were observed following α-methyl 5-HT applications. Both the excitations and inhibitions were unaffected by picrotoxin (50 μM, n = 5) and CNQX (10 μM, n = 5) indicative of direct postsynaptic effects. Thus, in STN neurones, 5-HT elicits two distinct effects, at times on the same neurone, the first being an excitation which is mediated by 5-HT 2C and 5-HT4 receptors and the second an inhibition which is mediated by 5-HT1A receptors. © 2005 Elsevier Ltd. All rights reserved.

Legitimacy building strategies in conditions of discretionary legal enforcement:a logic of social action approach

The present study explores strategies used to legitimize the transfer of organizational practices in a situation of institutional upheaval. We apply the logic of social action (Risse, 2000) to analyze the effectiveness of consequence-based action and communication-based action, in terms of higher coordination, lower conflict, and overall higher economic performance. Consequence-based legitimation is obtained by using a system of distributor incentives tied to performance of specific tasks, while communicative legitimation can be achieved by recommendations and warnings. Our setting is an export channel to European emerging economies. Our results indicate that in the absence of legitimacy, as manifested in discretionary legal enforcement, consequence-based legitimation is more effective than communicative legitimation in reducing conflict, increasing coordination, and ultimately in improving the performance of the export dyad. © 2014 Elsevier Inc.

β-cell-specific glucocorticoid reactivation attenuates inflammatory β-cell destruction

Progression and severity of type 1 diabetes is dependent upon inflammatory induction of nitric oxide production and consequent pancreatic β-cell damage. Glucocorticoids (GCs) are highly effective anti-inflammatory agents but have been precluded in type 1 diabetes and in islet transplantation protocols because they exacerbated insulin resistance and suppressed β-cell insulin secretion at the high-doses employed clinically. In contrast, physiological-range elevation of GC action within β-cells ameliorated lipotoxic β-cell failure in transgenic mice overexpressing the intracellular enzyme 11β-hydroxysteroid dehydrogenase type 1 (MIP-HSD1^tg/+ mice). Here, we tested the hypothesis that elevated β-cell 11beta-HSD1 protects against the β-cell destruction elicited by streptozotocin (STZ), a toxin that dose-dependently mimics aspects of inflammatory and autoimmune β-cell destruction. MIP-HSD1^tg/+ mice exhibited an episodic protection from the severe hyperglycemia caused by a single high dose of STZ associated with higher and sustained β-cell survival, maintained β-cell replicative potential, higher plasma and islet insulin levels, reduced inflammatory macrophage infiltration and increased anti-inflammatory T regulatory cell content. MIP-HSD1^tg/+ mice also completely resisted mild hyperglycemia and insulitis induced by multiple low-dose STZ administration. In vitro, MIP-HSD1^tg/+ islets exhibited attenuated STZ-induced nitric oxide production, an effect reversed with a specific 11beta-HSD1 inhibitor. GC regeneration selectively within β-cells protects against inflammatory β-cell destruction, suggesting therapeutic targeting of 11beta-HSD1 may ameliorate processes that exacerbate type 1 diabetes and that hinder islet transplantation.

Diabetes management in care homes:steps in the right direction?

Aims: Previous research has identified several inadequacies in management of diabetes within care homes many of which were highlighted in Diabetes UK’s report Diabetes in care homes:awareness, screening, training. The aim of this study was to see if this was still the case and to identify specific areas for improvement. Methods: Thirty care homes in Birmingham were invited to participate in the study. Data were collected using a standard questionnaire based on the Diabetes UK national survey of care homes comprising questions relating to screening, self-management, care planning and local authority support. All returned responses were analysed. Results: Responses were received from 20 of the 30 care homes approached. The mean percentage of residents with diabetes in the care homes sampled was 13.7%. None of the homes screened for diabetes on admission and only 5% screened residents annually.80% of homes acknowledged providing diabetes-specific training to staff. Residents in 95% of homes had a medical review in the last 12 months: 70% with a GP, 20% with a diabetes specialist nurse/nurse. 65% of homes provided support for self-management.45% of care homes did not have individualised care plans for residents with diabetes. 35% of managers reported poor support and guidance from their local authority.Conclusions: Improvements were noted in the care provided to individuals with diabetes living in care homes in Birmingham. Aspects relating to screening, individualised care plans and support to care home staff still need attention.

CloudMPL:a domain specific language for describing management policies for an autonomic cloud infrastructure

To benefit from the advantages that Cloud Computing brings to the IT industry, management policies must be implemented as a part of the operation of the Cloud. Among others, for example, the specification of policies can be used for the management of energy to reduce the cost of running the IT system or also for security policies while handling privacy issues of users. As cloud platforms are large, manual enforcement of policies is not scalable. Hence, autonomic approaches for management policies have recently received a considerable attention. These approaches allow specification of rules that are executed via rule-engines. The process of rules creation starts by the interpretation of the policies drafted by high-rank managers. Then, technical IT staff translate such policies to operational activities to implement them. Such process can start from a textual declarative description and after numerous steps terminates in a set of rules to be executed on a rule engine. To simplify the steps and to bridge the considerable gap between the declarative policies and executable rules, we propose a domain-specific language called CloudMPL. We also design a method of automated transformation of the rules captured in CloudMPL to the popular rule-engine Drools. As the policies are changed over time, code generation will reduce the time required for the implementation of the policies. In addition, using a declarative language for writing the specifications is expected to make the authoring of rules easier. We demonstrate the use of the CloudMPL language into a running example extracted from a management energy consumption case study.