bluuebunny/crossref_metadata_2025 huggingface dataset:
A placebo‐controlled trial of the 5‐HT1A agonist R‐137696 on symptoms, visceral hypersensitivity and on impaired accommodation in functional dyspepsia
Authors: Tack J. , Van Den Elzen B. , Tytgat G. , Wajs E. , Van Nueten L. , De Ridder F. , Boeckxstaens G.
Published: February 2009

Abstract  Acute studies suggested a therapeutic benefit for fundus‐relaxing drugs in functional dyspepsia (FD) with visceral hypersensitivity (VH) to gastric distention or impaired accommodation (IA), but long‐term studies are lacking. R‐137696 is a serotonin‐1A (5‐HT1A) receptor agonist which relaxes the proximal stomach in man. Our aim was to investigate the influence of R‐137696 on symptoms in FD with VH or IA. Randomized, double‐blind, placebo‐controlled, parallel group study of 4 weeks R‐137696 2 mg t.i.d. in FD with VH or IA. Symptoms were assessed using the patient assessment of upper gastrointestinal symptom severity index (PAGI‐SYM) total score and individual symptom subscales. Barostat studies were performed before and after 4 weeks of treatment. Fifty‐three patients (33 VH and 20 IA), 18 men, mean age 40 ± 13 years were recruited. Twenty‐four received placebo and 29 received R‐137696. In VH patients, both placebo and R‐137696 improved total symptom scores, with a tendency for superiority of placebo (−1.12 vs−0.51, P = 0.07). Placebo was superior for the subscales of early satiety, bloating, fullness and discomfort (all P < 0.05). In IA, both placebo and R‐137696 had no significant influence on total or individual symptom scores (−0.08 and −0.27). In VH, both placebo and R‐137696 increased the discomfort volume, without a statistical difference between both arms (+120 and +164 mL). In IA, both placebo and R‐137696 enhanced accommodation, without a statistical difference between both (+77 and +159 mL). Adverse events were similar for drug and placebo. A 4‐week administration of the fundus‐relaxing 5‐HT1A agonist R‐137696 failed to significantly improve symptoms, VH or gastric accommodation compared to placebo.
Pulmonary tuberculosis case detection through fortuitous cough screening during home visits
Authors: González‐Ochoa Edilberto , Brooks Jorge L. , Matthys Francine , Calisté Pausides , Armas Luisa , Van der Stuyft Patrick
Published: February 2009

Objective  To compare the yield of active tuberculosis (TB) case detection among risk groups during home visits with passive detection among patients at health services.

Methods  In April 2004, in a first phase, we introduced, active screening for coughing among all family members of patients that were visited at home by their family doctor or nurse for other reasons. Subsequently, from October 2004 onwards, active screening was restricted to family members belonging to groups at risk of TB.

Results  The overall detection rate of TB increased from 6.7/100 000 during passive detection at health services before the intervention to 26.2/100 000 inhabitants when passive detection was complemented by active case finding. Active screening among risk groups yielded 35 TB cases per 1000 persons screened compared to 20 TB cases per 1000 persons passively screened at health services. Active case finding was particularly efficient in those coughing for 3 weeks or more (107/1000 screened).

Conclusion  This study demonstrates that active case finding in groups at risk during home visits increases the case detection rate in the population and permits the identification of cases that may not be detected through passive case finding at health facility level.
Increased tolerance to oxidative stress in transgenic tobacco expressing a wheat oxalate oxidase gene via induction of antioxidant enzymes is mediated by H2O2
Authors: Wan Xiaoqing , Tan Jiali , Lu Shaoyun , Lin Chuyu , Hu Yihong , Guo Zhenfei
Published: February 2009

Hydrogen peroxide (H2O2) plays a key role in the regulation of plant responses to various environmental stresses and modulates the expression of related genes including those encoding antioxidant enzymes. A wheat oxalate oxidase (OxO) gene was transformed and expressed in tobacco for production of H2O2. The transgenic plants exhibited enhanced OxO activities and H2O2 concentrations, which was blocked by inhibitors of OxO. The transgenic plants showed increased tolerance to methyl viologen (MV) or high light‐induced oxidative stress in both short‐time and long‐time tests by measuring their maximal photochemical efficiency of PSII (Fv/Fm), ion leakage and malondialdehyde. Higher activities and transcripts of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) were observed in the transgenic plants compared to their wild‐type controls under normal growth conditions. Pretreatments with inhibitors of OxO and scavenger of H2O2 blocked the increase of tolerance to MV‐induced or high light‐induced oxidative stress, as well as the induction of antioxidant enzyme activities. Pretreatments with H2O2 increased tolerance to oxidative stresses and antioxidant enzyme activities. It is suggested that H2O2 produced by OxO in the transgenic tobacco plants triggers the signaling pathways to upregulate expressions of antioxidant enzyme genes, which in turn results in the increase of tolerance to MV‐induced and high light‐induced oxidative stresses.
Detection of urease in the cell wall and membranes from leaf tissues of bromeliad species
Authors: Aguetoni Cambuí Camila , Gaspar Marí lia , Mercier Helenice
Published: February 2009

Urea is an important nitrogen source for some bromeliad species, and in nature it is derived from the excretion of amphibians, which visit or live inside the tank water. Its assimilation is dependent on the hydrolysis by urease (EC: 3.5.1.5), and although this enzyme has been extensively studied to date, little information is available about its cellular location. In higher plants, this enzyme is considered to be present in the cytoplasm. However, there is evidence that urease is secreted by the bromeliad Vriesea gigantea, implying that this enzyme is at least temporarily located in the plasmatic membrane and cell wall. In this article, urease activity was measured in different cell fractions using leaf tissues of two bromeliad species: the tank bromeliad V. gigantea and the terrestrial bromeliad Ananas comosus (L.) Merr. In both species, urease was present in the cell wall and membrane fractions, besides the cytoplasm. Moreover, a considerable difference was observed between the species: while V. gigantea had 40% of the urease activity detected in the membranes and cell wall fractions, less than 20% were found in the same fractions in A. comosus. The high proportion of urease found in cell wall and membranes in V. gigantea was also investigated by cytochemical detection and immunoreaction assay. Both approaches confirmed the enzymatic assay. We suggest this physiological characteristic allows tank bromeliads to survive in a nitrogen‐limited environment, utilizing urea rapidly and efficiently and competing successfully for this nitrogen source against microorganisms that live in the tank water.
AtMBD8 is involved in control of flowering time in the C24 ecotype of Arabidopsis thaliana
Authors: Stangeland Biljana , Maryann Rosenhave E. , Winge Per , Berg Anita , Amundsen Silja S. , Karabeg Mirela , Mandal Abul , Bones Atle M. , Grini Paul E. , Aalen Reidunn B.
Published: February 2009

The Arabidopsis thaliana accession C24 is a vernalization‐responsive, moderately late flowering ecotype. We report that a mutation in AtMBD8, which encodes a protein with a putative Methyl‐CpG‐Binding Domain (MBD), in C24 background, results in a delay in flowering time during both long and short days. The atmbd8‐1 mutant responded to vernalization as wild type (wt) plants. Consistent with a role in modulation of flowering time, an AtMBD8::GUS‐reporter construct was expressed in the shoot meristem region and developing leaves. Full‐genome transcriptional profiling revealed very few changes in gene expression between atmbd8‐1 and wt plants. The expression level of FLC, the major repressor of transition to flowering, was unchanged in atmbd8‐1, and in accordance with that, genes upstream of FLC were unaffected by the mutation. The expression level of CONSTANS, involved in photoperiodic control of flowering, was very similar in atmbd8‐1 and wt plants. In contrast, the major promoters of flowering, FT and SOC1, were both downregulated. As FT is a regulator of SOC1, we conclude that AtMBD8 is a novel promoter of flowering that acts upstream of FT in the C24 accession. In contrast to atmbd8‐1, the Colombia (Col) SALK T‐DNA insertion line, atmbd8‐2, did not display a delayed transition to flowering. Transcriptional profiling revealed that a substantial number of genes were differentially expressed between C24 and Col wt seedlings. Several of these genes are also differentially expressed in late flowering mutants. We suggest that these differences contribute to the contrasting effect of a mutation in AtMBD8 in the two ecotypes.
Characterization of a mutant of Chlamydomonas reinhardtii deficient in the molybdenum cofactor
Authors: Li Wenze , Fingrut Daniel R. , Maxwell Denis P.
Published: February 2009

Molybdenum (Mo) is an essential micronutrient for almost all organisms. In eukaryotes, it forms a part of the molybdenum cofactor (Moco), which is required for numerous enzymes involved in carbon, nitrogen and sulfur metabolism. Mo is taken up by cells in the form of molybdate and recently molybdate transporters have been identified in Arabidopsis thaliana and Chlamydomonas reinhardtii. Here, we report the characterization of a novel mutant (DB6) of C. reinhardtii generated by random insertional mutagenesis that is unable to assimilate nitrate as a nitrogen source because it lacks functional nitrate reductase (NR). Besides lacking NR, DB6 also lacks xanthine dehydrogenase activity; a common requirement of both enzymes is Moco. DB6 displays a ‘molybdate‐repairable’ phenotype—growth on nitrate is partially restored by supplementing media with high levels of molybdate. This phenotype is typically associated with mutants defective in either molybdate transport or insertion of Mo into the pterin precursor of Moco. Mo content was found to be significantly lower in DB6 than in the wild‐type strain, AOXR1, which suggests that DB6 is defective in Mo uptake. Genetic complementation with a variety of candidate genes that include the known molybdate transporter MOT1 and DNA that spans the site of mutation was unable to recover the wild‐type phenotype. Taken together, our results indicate that DB6 is a novel molybdate transport‐deficient mutant.
Candidemia following solid organ transplantation in the era of antifungal prophylaxis: the Australian experience
Authors: Van Hal S.J. , Marriott D.J.E. , Chen S.C.A. , Nguyen Q. , Sorrell T.C. , Ellis D.H. , Slavin M.A. ,   the Australian Candidaemia Study
Published: February 2009

Abstract: Solid organ transplant (SOT) recipients have high rates of invasive fungal infections, with Candida species the most commonly isolated fungi. The aim of this study was to identify differences between incidence rates, risk factors, clinical presentations, and outcomes of candidemia in SOT recipients and non‐SOT patients. Data from the multicenter prospective Australian Candidaemia Study were examined. From August 2001 to July 2004, 24 episodes (2.2%; 24/1068) of candidemia were identified in SOT recipients. During this period, the numbers of transplanted organs included liver (n=455), kidney (n=1605), single lung (n=57), bilateral lung (n=183), heart and lung (n=18), heart (n=157), and pancreas (n=62). The overall annual estimated incidence of candidemia in SOT recipients was higher (3 per 1000 transplant admissions) than in non‐SOT patients (incidence 0.21 per 1000 admissions; P<0.001). The incidence and timing of candidemia post transplant was influenced by the transplanted organ type, with the majority of episodes (n=14, 54%) occurring >6 months after renal transplantation. Risk factors for candidemia in the month preceding diagnosis were similar to non‐SOT recipients except for corticosteroid therapy (P<0.001). Antifungal prophylaxis did not select for more resistant or non‐albicans Candida species in the SOT group. The 30‐day all‐cause mortality was similar to non‐SOT patients with candidemia and remains high at 21%. All deaths in SOT recipients occurred early (within 5 days of diagnosis), underlining a need for better diagnostic tests, targeted prevention, and early treatment strategies.
Unilateral versus bilateral endoscopic metal stenting for malignant hilar biliary obstruction
Authors: Naitoh Itaru , Ohara Hirotaka , Nakazawa Takahiro , Ando Tomoaki , Hayashi Kazuki , Okumura Fumihiro , Okayama Yasutaka , Sano Hitoshi , Kitajima Yasuhiro , Hirai Masaaki , Ban Tessin , Miyabe Katsuyuki , Ueno Koichiro , Yamashita Hiroaki , Joh Takashi
Published: February 2009

Background and Aim:  The extent of liver drainage for palliative treatment of malignant hilar biliary obstruction is controversial. The aim of this study was to compare endoscopic unilateral versus bilateral drainage in patients with malignant hilar biliary obstruction using a self‐expanding metal stent (SEMS).

Methods:  We carried out a retrospective review of 46 consecutive patients with malignant hilar biliary obstruction who were treated by endoscopic biliary drainage using SEMS between 1997 and 2005. Unilateral metal stenting (group A) was performed in 17 patients between 1997 and 2000, and bilateral metal stenting (group B) was performed in 29 patients between 2001 and 2005. The successful stent insertion, successful drainage, early complications, late complications, stent patency, and survival rate for groups A and B were evaluated and compared retrospectively.

Results:  There were no significant differences between the two groups in successful stent insertion (100% vs 90%, group A vs B, respectively), successful drainage (100% vs 96%), early complications (0% vs 10%), or late complications (65% vs 54%). Cumulative stent patency was significantly better in group B than in group A (P = 0.009). In cases of cholangiocarcinoma, cumulative stent patency was significantly better in group B than in group A (P = 0.009), whereas there were no inter‐group differences for gallbladder carcinoma. Cumulative survival did not differ significantly between the groups.

Conclusions:  Endoscopic bilateral drainage using SEMS for malignant hilar biliary obstruction is more effective than unilateral drainage in terms of cumulative stent patency, especially in cases of cholangiocarcinoma.
Thromboelastographic evaluation of coagulation in patients with extrahepatic portal vein thrombosis and non‐cirrhotic portal fibrosis: A pilot study
Authors: Kapoor Sorabh , Pal Sujoy , Sahni Peush , Chattopadhyay Tushar K
Published: February 2009

Background and Aims:  Non‐cirrhotic portal hypertension due to extrahepatic portal vein thrombosis (EHO) and non‐cirrhotic portal fibrosis (NCPF) is a major cause of upper gastrointestinal hemorrhage in India. Hypercoagulability has been proposed to explain the thrombosis in the portal vein in EHO and intrahepatic portal vein radicals in NCPF. However, some authors have reported hypocoagulability in these patients. Thromboelastography (TEG), which gives a dynamic assessment of coagulation, has potential for evaluating coagulation in these patients but has not been used so far. It was the aim of this study to evaluate the coagulation status in patients of EHO and NCPF using TEG.

Methods:  Thirty patients with EHO and 19 patients with NCPF were studied. TEG was done in all patients. R (reaction time), K (constant), α (angle), MA (maximal amplitude), A 60 (width of tracing after 60 min) were recorded and TEG index calculated and compared to controls.

Results:  Seven patients (23.3%) in the EHO group and eight (42.1%) in the NCPF group had severe thrombocytopenia (platlets, < 50 000 cells/dL). TEG showed significantly shorter R, higher MA and larger A in both EHO and NCPF compared to controls (P < 0.01). Thrombocytopenia normalized A but R continued to be significantly shorter in EHO and NCPF. Overt hypercoagulability (TEG index, > +2.5) was seen in two patients with EHO and one patient with NCPF.

Conclusion:  A latent hypercoagulable state exists in patients with EHO and NCPF which is partially masked by the thrombocytopenia secondary to splenomegaly and hypersplenism.
Role of the Oestrogen Receptors GPR30 and ERα in Peripheral Sensitization: Relevance to Trigeminal Pain Disorders in Women
Authors: Liverman CS , Brown JW , Sandhir R , McCarson KE , Berman NEJ
Published: February 2009

Oestrogen increases facial allodynia through its actions on activation of the MAPK extracellular-signal regulated kinase (ERK) in trigeminal ganglion neurons. This goal of study was to determine which oestrogen receptor is required for behavioural sensitization. Immunohistochemical studies demonstrated the presence of oestrogen receptor alpha (ERα) in nuclei of larger neurons and cytoplasm of smaller neurons, and the novel oestrogen receptor G-protein coupled receptor 30 (GPR30) in small diameter neurons that also contained peripherin, a marker of unmyelinated C-fibres. Specific agonists for ERα (PPT) and GPR30 (G-1), but not ERβ (DPN), activated ERK in trigeminal ganglion neurons in vitro. Both G-1 and PPT treatment increased allodynia after CFA injections into the masseter of ovariectomized Sprague-Dawley rats. Treatment with oestrogen increased expression of ERα but not GPR30, while masseter inflammation increased GRP30 but not ER α. Differential modulation of these ERK-coupled receptors by oestrogen and inflammation may play a role in painful episodes of temporomandibular disorder and migraine.
The Phosphorus Indicators Tool: a simple model of diffuse P loss from agricultural land to water
Authors: Heathwaite A.L. , Fraser A.I. , Johnes P.J. , Hutchins M. , Lord E. , Butterfield D.
Published: February 2009

Abstract. The Phosphorus Indicators Tool provides a catchment‐scale estimation of diffuse phosphorus (P) loss from agricultural land to surface waters using the most appropriate indicators of P loss. The Tool provides a framework that may be applied across the UK to estimate P loss, which is sensitive not only to land use and management but also to environmental factors such as climate, soil type and topography. The model complexity incorporated in the P Indicators Tool has been adapted to the level of detail in the available data and the need to reflect the impact of changes in agriculture. Currently, the Tool runs on an annual timestep and at a 1 km2 grid scale.

We demonstrate that the P Indicators Tool works in principle and that its modular structure provides a means of accounting for P loss from one layer to the next, and ultimately to receiving waters. Trial runs of the Tool suggest that modelled P delivery to water approximates measured water quality records. The transparency of the structure of the P Indicators Tool means that identification of poorly performing coefficients is possible, and further refinements of the Tool can be made to ensure it is better calibrated and subsequently validated against empirical data, as it becomes available.
The use of land evaluation information by land use planners and decision‐makers: a case study in Santa Catarina, Brazil
Authors: Bacic I.L.Z. , Rossiter D.G. , Bregt A.K.
Published: February 2009

Abstract. Land evaluation is the prediction of land performance over time under specific uses, to guide strategic land use decisions. Modern land evaluation has a 30 year history, yet the results have often been disappointing. Land users and planners have been reported to ignore land evaluations, perhaps reflecting poor quality, low relevance, or poor communication. To test the success of a large land evaluation exercise undertaken as part of micro‐catchment project in Santa Catarina State, southern Brazil, we queried agricultural extensionists, considered as the primary land evaluation clients. We used a questionnaire with both structured and open questions, to determine their experiences with, and attitudes to, the current land evaluation method. The soil resource inventory and associated land evaluation had some usefulness, but were not in general used for their intended purpose, namely farm planning. This was mainly because they did not contain crucial information necessary to such planning in the actual context of the farmer taking decisions. The primary deficiencies were identified as:

no estimate of environmental degradation risk;

no financial analysis;

no social analysis of decision‐makers' attitudes and preferences;

no risk assessment for weather, yields, profits and market; and

insufficiently‐specific alternative land uses.

These deficiencies could have been avoided with a demand‐driven approach, evaluating and reporting according to the true needs and opportunities of the decision‐makers.
Modelling of Cd, Cu, Ni, Pb and Zn uptake, by winter wheat and forage maize, from a sewage disposal farm
Authors: Hough R.L. , Hough R.L. , Young S.D. , Crout N.M.J.
Published: February 2009

Abstract. A predictive model of metal concentrations in crops was developed to optimize soil liming and sludge application strategies at a dedicated sewage sludge disposal site. Predictions of metal concentrations in plant tissue were derived from measured values of soil metal concentration, humus content and soil pH. The plant and soil data used to parameterize the model were collected on site using quadrat sampling of mature crop and underlying topsoil. The uptake model was used to map predicted metal concentrations in wheat grain and forage maize based upon a database of soil characteristics (metal content, % humus and pH) measured as part of a routine geochemical survey of the site. The effect of a management strategy to modify uptake of Cd by wheat by changing soil pH was investigated. The effect of soil dust adhering to maize plants at harvest was also simulated to investigate the importance of this pathway for Cd transfer to animal feed such as silage.

The model gave satisfactory predictions for uptake of Cd and Zn but less useful simulations for Pb, Cu and Ni. The results for Cd uptake showed a greater dependence on soil pH in the case of wheat in comparison to maize. It is suggested that, for the study site, liming to pH 7.0 will reduce Cd concentrations in wheat grain to within EC legal standards. However the Cd content of maize may still exceed these guidelines, with a relatively minor contribution from contamination with soil dust.
Effectiveness of different precipitated phosphates as phosphorus sources for plants
Authors: Johnston A.E. , Richards I.R.
Published: February 2009

Abstract. Eleven precipitated phosphates were evaluated as sources of phosphorus (P) for plant growth by comparing their effectiveness with that of monocalcium phosphate, a source of water soluble P that is generally considered to be fully plant available. The precipitated phosphates comprised struvites recovered from waste water discharges (mainly magnesium ammonium phosphate), laboratory synthesised struvites, a synthetic iron phosphate and a recovered calcium phosphate. Precipitating phosphates in these forms could be a way for removing P from waste water before it is discharged to rivers, so reducing the risk of eutrophication. Application to agricultural land would be one potential use for such phosphates. Evaluation was by pot experiments with a sandy loam soil and with a sandy clay loam soil using perennial ryegrass (Lolium perenne) as the test crop. The soils differed in pH (6.6 and 7.1) and in Olsen P (28 and 11 mg L−1). Measured variables were grass dry matter (DM) yield and grass P concentration which were used to calculate offtake of P in the harvested grass. DM yields of ryegrass and P offtakes given by the synthetic and recovered struvites were not significantly different statistically either between themselves or to MCP applied at the same rate. On this basis these struvites could be used to recycle P to similar soils and the effect of the P on crop yield should be similar to that of MCP
A simple procedure for assessing soil structural, rooting and surface conditions
Authors: Ball B.C. , Douglas J.T.
Published: February 2009

Abstract. We present a semi‐quantitative visual and tactile method for assessing soil physical fertility in terms of soil structure, root growth and soil surface condition. A block of topsoil is dug out with a spade. Horizontal layers (usually 2–4) are then identified as they appear. A brief one‐page description of the soil is produced. Using a key, structural and rooting scores are assigned to each soil layer from the appearance of the soil and from its response to tactile assessment. These scores are then combined across depths, with weighting appropriate for the depth of each layer. A separate score was made of soil surface condition. Thus, overall soil physical fertility is assessed as three scores for topsoil structure, rooting and surface condition. The usefulness and sensitivity of the procedure were tested in two ley‐arable organic rotation experiments on sandy loams in northeast Scotland.
Methane fluxes on agricultural and forested boreal organic soils
Authors: Maljanen M. , Liikanen A. , Silvola J. , Martikainen P.J.
Published: February 2009

Abstract. Annual methane fluxes from an organic soil in eastern Finland, originally drained and planted with birch (Betula pendula) and then later cultivated, were studied for two years using a chamber technique. The agricultural soils growing grass or barley or without vegetation, generally acted as sinks for CH4. Surprisingly, the agricultural soils emitted CH4 during a warm dry summer. The CH4 oxidation capacity and CH4 uptake rate of the forested site was three times that of agricultural soils. Also, the forest soil better retained its capacity to take up CH4 during a dry summer. Despite periods of CH4 emission, the agricultural soils were annual sinks for CH4, with uptake rate of CH4‐C varying from 0.1 to 3.7 kg ha−1 yr−1. The forested soil had a methane uptake rate of 3.9 kg CH4‐C ha−1 yr−1. All the soils acted as sinks for CH4 during winter, which contributed up to half of the annual CH4 uptake. The capacity of soils to transport gases did not explain the larger CH4 uptake rate in the forest soil. At the same gas filled porosity, the forest soil had a much larger CH4 uptake rate than the agricultural soil. Neither the soil acidity (pH 4.5 and 6.0) nor high ammonium content appeared to limit CH4 uptake. The results suggest that CH4 oxidation in agricultural organic soil is more sensitive to soil drying than CH4 oxidation in forested organic soil.
Incentive Contracting and Value Relevance of Earnings and Cash Flows
Authors: BANKER RAJIV D. , HUANG RONG , NATARAJAN RAMACHANDRAN
Published: February 2009

Accounting performance measures such as earnings and cash flows are useful for both valuation and performance evaluation purposes. However, little evidence exists on whether there is any association between these two roles. In this study, we provide large sample empirical evidence that the value relevance of earnings explains a significant amount of the cross‐sectional variation in the pay‐sensitivity of earnings and the incremental value relevance of cash flows explains variation in the marginal pay‐sensitivity of cash flows. We document that while both value relevance and compensation weight on earnings decline from the subperiod of 1993 to 1997 to the subperiod of 1998 to 2003, both value relevance and compensation weight on cash flows increase from the earlier subperiod to the later subperiod. Overall, our results provide additional evidence that value relevance of a performance measure plays a significant role in its use for performance evaluation.
Shared Memories, Common Vision: Generations, Sociopolitical Consciousness and Resistance among Cuban Women*
Authors: Krull Catherine , Kobayashi Audrey
Published: February 2009

Much has been written about modern Cuba's problems, but little about what it means to be part of a society that believes in “the Revolution” and the possibility of a new order. The challenge is not only to understand why some Cubans do not believe but to also recognize the commitment of those who do. Based on how they identify key events in Cuban history, we focus on two distinct generations of Cuban women: an older “Revolution” generation and a younger “Special Period” generation. Analyzing transcripts from in‐depth focus group conversations and face‐to‐face interviews, we argue that depending on their historical location, Cuban women differ both within and between generations in terms of their sociopolitical world views, especially in how they conceptualize their place in the Revolution and in their strategies of resistance throughout Cuba's current economic crisis, a period known by Cubans as the Special Period. Their words describe in detail what their beliefs mean to them, and how they live them.
Identification of the amino acid residues in the extracellular domain of rat P2X7 receptor involved in functional inhibition by acidic pH
Authors: Liu X , Ma W , Surprenant A , Jiang L‐H
Published: February 2009

Background and purpose:  P2X7 receptors are potently inhibited by extracellular acidification. The underlying molecular basis remains unknown. This study aimed to examine the role of extracellular histidine, lysine, aspartic acid and glutamic acid residues in the functional inhibition of rat P2X7 receptors by acidic pH.

Experimental approach:  We introduced point mutations into rat P2X7 receptor by site‐directed mutagenesis, expressed wild type (WT) and mutant receptors in human embryonic kidney (HEK293) cells and, using patch clamp recording, characterized the effects of acidic pH on BzATP [2′‐3′‐O‐(4‐benzoylbenzoyl) adenosine 5′‐triphosphate]‐evoked ionic currents.

Key results:  Reducing extracellular pH, that is, increasing extracellular proton concentrations, inhibited BzATP‐evoked currents in cells expressing WT P2X7 receptors, with IC50 value (half‐maximal antagonist or inhibitor concentration) for protons of 0.2 µmol·L−1. The major effect of acidification was suppression of the maximal current response without altering the agonist sensitivity. Five residues in the receptor extracellular domain (His85, Lys110, Lys137, Asp197 and His219) were mutated to alanine and current inhibition by protons assessed. Compared with WT, the H85A, H219A, K137A mutants were two‐ to threefold more sensitive, whereas the K110A and D197A mutants were 2.5‐ and 9‐fold less sensitive. Double‐alanine substitution of Lys110 and Asp197 resulted in 23‐fold decreased sensitivity to inhibition by protons. Furthermore, charge neutralization (K110M, K110F, D197N and D197F), but not charge conserving mutation (K110R and D197E), attenuated the inhibition of currents by protons.

Conclusions and implications:  Functional inhibition of rat P2X7 receptors by acidic pH was variably affected by the extracellular His85, Lys110, Lys137, Asp197 and His219 residues, with the Asp197 residue being most critical for this inhibition.
Effect of Δ9‐tetrahydrocannabinol, a cannabinoid receptor agonist, on the triggering of transient lower oesophageal sphincter relaxations in dogs and humans
Authors: Beaumont H , Jensen J , Carlsson A , Ruth M , Lehmann A , Boeckxstaens GE
Published: February 2009

Background and purpose:  Transient lower oesophageal sphincter relaxations (TLESRs) are the main mechanism underlying gastro‐oesophageal reflux and are a potential pharmacological treatment target. We evaluated the effect of the CB1/CB2 receptor agonist Δ9‐tetrahydrocannabinol (Δ9‐THC) on TLESRs in dogs. Based on these findings, the effect of Δ9‐THC was studied in healthy volunteers.

Experimental approach:  In dogs, manometry was used to evaluate the effect of Δ9‐THC in the presence and absence of the CB1 receptor antagonist SR141716A on TLESRs induced by gastric distension. Secondly, the effect of 10 and 20 mg Δ9‐THC was studied in 18 healthy volunteers in a placebo‐controlled study. Manometry was performed before and for 3 h after meal ingestion on three occasions.

Key results:  In dogs, Δ9‐THC dose‐dependently inhibited TLESRs and reduced acid reflux rate. SR141716A significantly reversed the effects of Δ9‐THC on TLESRs. Similarly, in healthy volunteers, Δ9‐THC significantly reduced the number of TLESRs and caused a non‐significant reduction of acid reflux episodes in the first postprandial hour. In addition, lower oesophageal sphincter pressure and swallowing were significantly reduced by Δ9‐THC. After intake of 20 mg, half of the subjects experienced nausea and vomiting leading to premature termination of the study. Other side‐effects were hypotension, tachycardia and central effects.

Conclusions and implications:  Δ9‐THC significantly inhibited the increase in meal‐induced TLESRs and reduced spontaneous swallowing in both dogs and humans. In humans, Δ9‐THC significantly reduced basal lower oesophageal sphincter pressure. These findings confirm previous observations in dogs and indicate that cannabinoid receptors are also involved in the triggering of TLESRs in humans.
Characterization of BK channel splice variants using membrane potential dyes
Authors: Saleem F , Rowe ICM , Shipston MJ
Published: February 2009

Background and purpose:  Large conductance calcium‐ and voltage‐activated potassium (BK) channels are encoded by a single gene that displays extensive pre‐mRNA splicing. Here we exploited a membrane potential assay to investigate the sensitivity of different BK splice variants to elevations in intracellular free calcium and their inhibition by the BK channel blocker paxilline.

Experimental approach:  Murine BK channel splice variants were expressed in human embryonic kidney 293 cells and their properties analysed in response to ionomycin‐induced calcium influx in both fluorescent membrane potential (fluorescent‐imaging plate reader) and patch clamp electrophysiological assays. The dose‐dependent inhibition of distinct splice variants by the BK channel‐specific blocker paxilline was also investigated.

Key results:  Ionomycin‐induced calcium influx induced a robust hyperpolarization of human embryonic kidney 293 cells expressing distinct BK channel splice variants: stress regulated exon (STREX), e22 and ZERO. Splice variant expression resulted in membrane hyperpolarization that displayed a rank order of potency in response to calcium influx of STREX > e22 > ZERO. The BK channel inhibitor paxilline exhibited very similar potency on all three splice variants with IC50s in membrane potential assays of 0.35 ± 0.04, 0.37 ± 0.03 and 0.70 ± 0.02 µmol·L−1 for STREX, ZERO and e22 respectively.

Conclusions and implications:  BK channel splice variants can be rapidly discriminated using membrane potential based assays, based on their sensitivity to calcium. BK channel splice variants are inhibited by the specific blocker paxilline with similar IC50s. Thus, paxilline may be used in functional assays to inhibit BK channel function, irrespective of the variant expressed.
Inhibition of the phosphatase PTEN protects mice against oleic acid‐induced acute lung injury
Authors: Lai Ju‐Ping , Bao Shengying , Davis Ian C. , Knoell Daren L.
Published: February 2009

Background and purpose:  Injury to the lung parenchyma is a constitutional feature shared by many lung diseases. The protein, phosphatase and tensin homologue deleted on chromosome Ten (PTEN) is a major suppressor of phosphoinositide‐3 kinase/Akt signalling, a vital survival pathway in lung parenchymal cells. Based on this, we hypothesized that PTEN inhibition in vivo would enhance cell tolerance to stress thereby preventing acute lung injury.

Experimental approach:  We evaluated the ability of a PTEN inhibitor, potassium bisperoxo (1,10‐phenanthroline) oxovanadate [bpV(phen)], to prevent acute lung injury induced by oleic acid (OA) in adult C57BL/6 mice. Lung assessments included bronchoalveolar lavage, tissue morphology, immunostaining for markers of cell death, cell identity, phospho‐Akt and phospho‐ERK levels and oximetry.

Key results:  OA induced acute lung injury in a dose‐ and time‐dependent manner. No injury was observed in the vehicle control or bpV(phen) treatment groups. PTEN inhibition by bpV(phen) increased lung tissue levels of phospho‐Akt and ERK and but not focal adhesion kinase. This occurred in conjunction with a statistically significant reduction in protein content, lactate dehydrogenase, as well as tumour necrosis factor‐α and chemokines in bronchoalveolar lavage fluid when compared with OA treatment alone. The incidence of alveolar lesions, consistent with acute lung injury, and terminal uridine deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)‐positive cells was also significantly reduced. Importantly, PTEN suppression maintained pulmonary function.

Conclusions and implications:  Treatment with bpV(phen) significantly reduced the severity of acute lung injury in mice indicating that additional investigation is warranted to understand the important role that this phosphatase may play in the lung.
Etanercept prevents airway hyperresponsiveness by protecting neuronal M2 muscarinic receptors in antigen‐challenged guinea pigs
Authors: Nie Zhenying , Jacoby David B. , Fryer Allison D.
Published: February 2009

Background and purpose:  Increased tumour necrosis factor‐α (TNF‐α) is associated with airway hyperreactivity in antigen‐challenged animals. In human asthmatics, TNF‐α is increased and blocking it prevents airway hyperreactivity in some asthmatic patients. However, the mechanisms by which TNF‐α mediates hyperreactivity are unknown. Airway hyperreactivity can be caused by dysfunction of neuronal M2 muscarinic receptors that normally limit acetylcholine release from parasympathetic nerves. Here we test whether blocking TNF‐α receptors with etanercept prevents M2 receptor dysfunction and airway hyperreactivity in antigen‐challenged guinea pigs.

Experimental approach:  Ovalbumin‐sensitized guinea pigs were challenged by inhalation of antigen. Some animals received etanercept (3 mg kg−1 i.p.) 3 h before challenge. 24 h after challenge, airway hyperreactivity and M2 receptor function were tested. Inflammatory cells in bronchoalveolar lavage, blood and lung were counted. TNF‐α and its receptors were detected by real‐time RT‐PCR and immunocytochemistry in parasympathetic nerves from humans and guinea pigs and in human neuroblastoma cells.

Key results:  Antigen‐challenged animals were hyperreactive to vagal stimulation and neuronal M2 receptors were dysfunctional. Both M2 receptor dysfunction and airway hyperreactivity were prevented by etanercept. Etanercept reduced eosinophils around airway nerves, and in blood, bronchoalveolar lavage and airway smooth muscle. Also, TNF‐α decreased M2 receptor mRNA in human and guinea pig parasympathetic neurons.

Conclusions and implications:  Tumour necrosis factor‐α may contribute to M2 receptor dysfunction and airway hyperreactivity directly by decreasing receptor expression and indirectly by promoting recruitment of eosinophils, containing major basic protein, an M2 antagonist. This suggests that etanercept may be beneficial in treatment of allergic asthma.
Nonparametric Estimation of Oligopsony Power in First‐Price Auction
Authors: Chung Chanjin , Tostão Emílio
Published: February 2009

This paper proposes a nonparametric procedure to estimate market power for first‐price auction data and applies the procedure to cattle procurement markets. Most previous studies have used parametric methods, which require specific functional forms for retail demand, input supply and processors’ cost equations. However, researchers often find that market power estimates from parametric methods are sensitive to the choice of functional forms and specifications. An application to data from cattle procurement experiments shows that our nonparametric approach greatly outperforms commonly used parametric methods in estimating the degree of market power. While parametric estimates are sensitive to functional form specification and are at least 90% smaller than ‘true’ market power indices, estimates from our nonparametric procedure deviate from the actual value by no more than 25%.
Heterogeneous Risk Preferences, Discount Rates and Land Contract Choice in Ethiopia
Authors: Bezabih Mintewab
Published: February 2009

This paper analyses the role of risk and rate of time preference in the choice of land contracts. The analysis builds on the risk‐sharing and imperfect market explanations of contract choice. Unique data from Ethiopia, which contain land contract information and experimental risk and rate of time preference measures on matched landlord–tenant partners, are employed in the empirical analysis. The results show that landlord and tenant time preferences are significant determinants of contract choice. For landlords (but not tenants), risk preference is also significant, indicating the importance of financial constraints and production risk in the determination of contract choice. The results are of particular relevance to land market policy in Ethiopia, where production is risk‐prone, financial markets are imperfect, and where there is a major need for the development of vibrant land rental markets.
Production Efficiency of Jasmine Rice Producers in Northern and North‐eastern Thailand
Authors: Rahman Sanzidur , Wiboonpongse Aree , Sriboonchitta Songsak , Chaovanapoonphol Yaovarate
Published: February 2009

The paper jointly evaluates the determinants of switching to Jasmine rice and its productivity while allowing for production inefficiency at the level of individual producers. Model diagnostics reveal that serious selection bias exists, justifying use of a sample selection framework in stochastic frontier models. Results from the probit variety selection equation reveal that gross return (mainly powered by significantly higher Jasmine rice price), access to irrigation and education are the important determinants of choosing Jasmine rice. Results from the stochastic production frontier reveal that land, irrigation and fertilisers are the significant determinants of Jasmine rice productivity. Significantly lower productivity in Phitsanulok and Tung Gula Rong Hai provinces demonstrate the influence of biophysical and environmental factors on productivity performance. The mean level of technical efficiency is estimated at 0.63 suggesting that 59% [(100 − 63)/63] of the productivity is lost due to technical inefficiency. Policy implications include measures to keep Jasmine rice price high, increase access to irrigation and fertiliser availability, as well as investment in education targeted to farm households which will synergistically increase adoption of Jasmine rice as well as farm productivity.
Restoration of a Mediterranean Postfire Shrubland: Plant Functional Responses to Organic Soil Amendment
Authors: Larchevêque Marie , Ballini Christine , Baldy Virginie , Korboulewsky Nathalie , Ormeño Elena , Montès Nicolas
Published: February 2009

We investigated the potential of plant functional responses to speed up restoration in a postfire ecosystem. The patterns of change in plant nutrient uptake and water potential after compost amendment were monitored for 2 years in a 7‐year‐old postfire shrubland in southeastern France. We studied four different stress‐tolerant species with contrasting life traits: three shrub species and a perennial herb. Three treatments were applied: control, 50 and 100 Mg/ha of fresh cocomposted sewage sludge and green waste. In both compost treatments, concentrations of all the macronutrients increased. The amendment improved N and cation nutrition, but the positive effect of compost on plant nutrient status was most apparent on leaf P concentrations, indicating that P was a limiting nutrient in this shrubland. Compost had no significant short‐term effect on trace metal concentrations in plants. The plant nutrition response of different species to the compost varied; the nutritional status of Brachypodium retusum and Cistus albidus improved the most, whereas that of Quercus coccifera and Ulex parviflorus improved the least. Woody species exhibited no increase in N stocks. Phosphorus accumulation was also about three times higher in plots amended at 50 Mg/ha than in control plots for B. retusum and C. albidus. The severe summer drought of 2003 altered the compost effect. Contrary to our expectations, plants on amended plots did not exhibit a better water status in summer: the effect of the summer drought had a greater effect on water status than did the compost treatment.
Different patterns of neuronal activation and neurodegeneration in the thalamus and cortex of epilepsy‐resistant Proechimys rats versus Wistar rats after pilocarpine‐induced protracted seizures
Authors: Andrioli Anna , Fabene Paolo F. , Spreafico Roberto , Cavalheiro Esper A. , Bentivoglio Marina
Published: February 2009

Purpose:  To analyze cellular mechanisms of limbic‐seizure suppression, the response to pilocarpine‐induced seizures was investigated in cortex and thalamus, comparing epilepsy‐resistant rats Proechimys guyannensis with Wistar rats.

Methods:  Fos immunoreactivity revealing neuronal activation, and degenerating neurons labeled by Fluoro‐Jade B (FJB) histochemistry were analyzed on the first day after onset of seizures lasting 3 h. Subpopulations of γ‐aminobutyric acid (GABA)ergic cells were characterized with double Fos‐parvalbumin immunohistochemistry.

Results:  In both cortex and thalamus, degenerating neurons were much fewer in Proechimys than Wistar rats. Fos persisted at high levels at 24 h only in the Proechimys thalamus and cortex, especially in layer VI where corticothalamic neurons reside. In the parietal cortex, about 50% of parvalbumin‐containing interneurons at 8 h, and 10–20% at 24 h, were Fos‐positive in Wistar rats, but in Proechimys, Fos was expressed in almost all parvalbumin‐containing interneurons at 8 h and dropped at 24 h. Fos positivity in cingulate cortex interneurons was similar in both species. In the Wistar rat thalamus, Fos was induced in medial and midline nuclei up to 8 h, when <30% of reticular nucleus cells were Fos‐positive, and then decreased, with no relationship with cell loss, evaluated in Nissl‐stained sections. In Proechimys, almost all reticular nucleus neurons were Fos‐positive at 24 h.

Discussion:  At variance with laboratory rats, pilocarpine‐induced protracted seizures elicit in Proechimys limited neuronal death, and marked and long‐lasting Fos induction in excitatory and inhibitory cortical and thalamic cell subsets. The findings implicate intrathalamic and intracortical regulation, and circuits linking thalamus and cortex in limbic seizure suppression leading to epilepsy resistance.