bluuebunny/crossref_metadata_2025 huggingface dataset:
Useful principles for adopting a market development approach for enterprise development organizations
Authors: Lusby Frank
Published: September 2006

Purpose

To provide a practitioner focused discussion for enterprise development organizations (EDOs) who are seeking to incorporate principles of sustainability into their strategies.

Design/methodology/approach

Presents general principles that can be useful to EDOs who are trying to take on a more market development (sustainable) approach to enterprise development.

Findings

The principles can be applied to economic development projects that target small, medium or large enterprises. They apply to programs promoting agricultural, manufacturing, and services – and also have application in other sectors such as health, conservation, and education.

Originality/value

Provides leading insights into EDO strategies.
Portrayals of F.W. Taylor across textbooks
Authors: Payne Stephanie C. , Youngcourt Satoris S. , Watrous Kristen M.
Published: September 2006

Purpose

To conduct a content analysis of the portrayal of Frederick W. Taylor in management and psychology textbooks to reveal differences both within and across disciplines.

Design/methodology/approach

Forty‐four textbooks from six sub‐disciplines within management and psychology were content analyzed for the amount and accuracy of the material presented about Taylor and the extent to which key terms were included in these descriptions.

Findings

The data show that more information is provided in the management texts and the majority of the information conveyed across disciplines appears accurate.

Research limitations/implications

Not all textbooks were examined within all sub‐disciplines within management or psychology or all sub‐disciplines to which Taylor ostensibly contributed. Future research is needed to determine why Taylor is portrayed differently across texts.

Practical implications

Results have important teaching implications as they reveal how accurately textbooks portray one controversial historical figure and what students are learning. Students might be encouraged to consult original sources and information beyond the text. Textbook authors should be held accountable for the accuracy of the information in their texts and may find the comparison information informative. Instructors may find the results useful when selecting a new text.

Originality/value

This paper depicts variability in how historical figures are depicted in textbooks, which is an important part of management history education.
Transfer of Taylorist ideas to China, 1910‐1930s
Authors: Morgan Stephen L.
Published: September 2006

Purpose

Management is a “hot field” in China, yet little has been written in English about the history of management in China. Contrary to contemporary management literature, the paper aims to show that Chinese entrepreneurs and managers were exposed to modern management ideas from the early twentieth century. The paper is an initial exploration of the transfer of managerial knowledge to China, especially Scientific Management, during the interwar period.

Design/methodology/approach

Draws on Chinese journal articles and books from 1910‐1930s, supplemented with archive materials and secondary sources in Chinese and English.

Findings

Chinese industrialists, officials and academics were attracted to Taylor's ideas of scientific management during the 1920s and 1930s, which were experimented with on a wider scale than is commonly realized. The interest in “new” management extended beyond industrialists and industry officials to reportage in the popular press.

Research limitations/implications

Future research should consider first how new ideas about management and organization were implemented on the shopfloor in individual Chinese enterprises, and second examine the role of social networks constituted by native place, industry ties and professional association membership in the diffusion of managerial ideas among the Chinese business elite of the period.

Originality/value

The paper shows that the transfer to China of modern management as an ideas system was not a recent phenomenon, but part of a century‐long process of transfer and adaptation of western management theory and practice.
Evaluating management accounting change according to the institutional theory approach
Authors: Guerreiro Reinaldo , Pereira Carlos Alberto , Frezatti Fábio
Published: September 2006

Purpose

The objective of this case study is to evaluate the change process, under the old institutional economics (OIE) approach, that had occurred within the management‐accounting system of Brazilian bank. The present study examines the efficacy of the change process in management accounting, from the perspective of system users, seven years after its beginning.

Design/methodology/approach

The research is based on a case study. The study presents a literature review of institutional theory and a case study of Banco do Brasil – a large Brazilian bank that has implemented profound changes in its management‐accounting system.

Findings

The results indicate that new concepts have been effectively institutionalised and converted into new values, habits, and routines inside the organisation. The study provides new insights into management‐accounting change.

Research limitations/implications

A single case study does not allow the results to be generalised to other organisations.

Originality/value

The study offers a conceptual structure and operational guidelines to evaluate institutionalisation of management‐accounting change processes. The main contribution of this study is to offer new operational insights on management‐ accounting institutionalisation using the conceptual framework proposed by Burns and Scapens.
Spreadsheets and the financial planning process: a case study of resistance to change
Authors: Howcroft Douglas
Published: September 2006

Purpose

The purpose of this paper is to identify and explain the barriers that prevented the case study organisation, a UK manufacturing and R&D subsidiary of a European transnational company, from improving its spreadsheet‐based financial planning process.

Design/methodology/approach

This is an insider action research case study, using qualitative semi‐structured interviews to ask accountants their opinions on budgeting and whether the present spreadsheet‐based budgeting system could be improved. In addition, a quantitative questionnaire was used to ask managers their views on whether budgeting was a help or a hindrance.

Findings

Changes to the existing financial planning process were not implemented because they threatened to alter the existing distribution of power within the finance organisation.

Research limitations/implications

The research project could not have proceeded into an implementation of change cycle due to financial constraints and because the manufacturing sites where the study took place were closed down. Further research into the organisational politics and culture of the case study organisation would have been an interesting challenge.

Practical implications

Consistent with previous research that existing power distribution and organisation cultures may stifle creativity and be the cause of resistance, preventing changes to accounting systems being implemented.

Originality/value

Why management systems are resistant to change has occupied researchers in recent times. However, there has been a dearth of action research on budgeting and financial planning, particularly insider action research. This paper contributes to the developing body of action research literature on management accounting systems.
The crystal structure of the E. coli stress protein YciF
Authors: Hindupur Aditya , Liu Deqian , Zhao Yonghong , Bellamy Henry D. , White Mark A. , Fox Robert O.
Published: September 2006

YciF is a protein that is up‐regulated when bacteria experience stress conditions, and is highly conserved in a range of bacterial species. YciF has no known structure or biochemical function. To learn more about its potential molecular function and its role in the bacterial stress response, we solved the crystal structure of YciF at 2.0 Å resolution by the multiple wavelength anomalous diffraction (MAD) technique. YciF is a dimer in solution, and forms a homodimer in the crystal asymmetric unit. The two monomers form a dimer with a molecular twofold axis, with a significant burial of solvent‐accessible surface area. The protein is an all‐alpha protein composed of five helices: a four‐helix bundle, and a short additional helix at the dimer interface. The protein is structurally similar to portions of the diiron‐containing proteins, rubrerythrin and the Bacillus anthracis Dlp‐2.
Stabilization of a binary protein complex by intein‐mediated cyclization
Authors: Jeffries Cy M. , Graham Stephen C. , Stokes Philippa H. , Collyer Charles A. , Guss J. Mitchell , Matthews Jacqueline M.
Published: September 2006

The study of protein–protein interactions can be hampered by the instability of one or more of the protein complex components. In this study, we showed that intein‐mediated cyclization can be used to engineer an artificial intramolecular cyclic protein complex between two interacting proteins: the largely unstable LIM‐only protein 4 (LMO4) and an unstructured domain of LIM domain binding protein 1 (ldb1). The X‐ray structure of the cyclic complex is identical to noncyclized versions of the complex. Chemical and thermal denaturation assays using intrinsic tryptophan fluorescence and dynamic light scattering were used to compare the relative stabilities of the cyclized complex, the intermolecular (or free) complex, and two linear versions of the intramolecular complex (in which the interacting domains of LMO4 and ldb1 were fused, via a flexible linker, in either orientation). In terms of resistance to denaturation, the cyclic complex is the most stable variant and the intermolecular complex is the least stable; however, the two linear intramolecular variants show significant differences in stability. These differences appear to be related to the relative contact order (the average distance in sequence between residues that make contacts within a structure) of key binding residues at the interface of the two proteins. Thus, the restriction of the more stable component of a complex may enhance stability to a greater extent than restraining less stable components.
Prediction of residues in discontinuous B‐cell epitopes using protein 3D structures
Authors: Haste Andersen Pernille , Nielsen Morten , Lund Ole
Published: September 2006

Discovery of discontinuous B‐cell epitopes is a major challenge in vaccine design. Previous epitope prediction methods have mostly been based on protein sequences and are not very effective. Here, we present DiscoTope, a novel method for discontinuous epitope prediction that uses protein three‐dimensional structural data. The method is based on amino acid statistics, spatial information, and surface accessibility in a compiled data set of discontinuous epitopes determined by X‐ray crystallography of antibody/antigen protein complexes. DiscoTope is the first method to focus explicitly on discontinuous epitopes. We show that the new structure‐based method has a better performance for predicting residues of discontinuous epitopes than methods based solely on sequence information, and that it can successfully predict epitope residues that have been identified by different techniques. DiscoTope detects 15.5% of residues located in discontinuous epitopes with a specificity of 95%. At this level of specificity, the conventional Parker hydrophilicity scale for predicting linear B‐cell epitopes identifies only 11.0% of residues located in discontinuous epitopes. Predictions by the DiscoTope method can guide experimental epitope mapping in both rational vaccine design and development of diagnostic tools, and may lead to more efficient epitope identification.
A fast method for the determination of fractional contributions to solvation in proteins
Authors: Talavera David , Morreale Antonio , Meyer Tim , Hospital Adam , Ferrer‐Costa Carles , Gelpi Josep Lluis , de la Cruz Xavier , Soliva Robert , Luque F. Javier , Orozco Modesto
Published: September 2006

A fast method for the calculation of residue contributions to protein solvation is presented. The approach uses the exposed polar and apolar surface of protein residues and has been parametrized from the fractional contributions to solvation determined from linear response theory coupled to molecular dynamics simulations. Application of the method to a large subset of proteins taken from the Protein Data Bank allowed us to compute the expected fractional solvation of residues. This information is used to discuss when a residue or a group of residues presents an uncommon solvation profile.
Crystal structures of the DNA‐binding domain of Escherichia coli proline utilization A flavoprotein and analysis of the role of Lys9 in DNA recognition
Authors: Larson John D. , Jenkins Jermaine L. , Schuermann Jonathan P. , Zhou Yuzhen , Becker Donald F. , Tanner John J.
Published: September 2006

PutA (proline utilization A) from Escherichia coli is a 1320‐amino‐acid residue protein that is both a bifunctional proline catabolic enzyme and an autogenous transcriptional repressor. Here, we report the first crystal structure of a PutA DNA‐binding domain along with functional analysis of a mutant PutA defective in DNA binding. Crystals were grown using a polypeptide corresponding to residues 1–52 of E. coli PutA (PutA52). The 2.1 Å resolution structure of PutA52 mutant Lys9Met was determined using Se‐Met MAD phasing, and the structure of native PutA52 was solved at 1.9 Å resolution using molecular replacement. Residues 3–46 form a ribbon–helix–helix (RHH) substructure, thus establishing PutA as the largest protein to contain an RHH domain. The PutA RHH domain forms the intertwined dimer with tightly packed hydrophobic core that is characteristic of the RHH family. The structures were used to examine the three‐dimensional context of residues conserved in PutA RHH domains. Homology modeling suggests that Lys9 and Thr5 contact DNA bases through the major groove, while Arg15, Thr28, and His30 may interact with the phosphate backbone. Lys9 is shown to be essential for specific recognition of put control DNA using gel shift analysis of the Lys9Met mutant of full‐length PutA. Lys9 is disordered in the PutA52 structure, which implies an induced‐fit binding mechanism in which the side chain of Lys9 becomes ordered through interaction with DNA. These results provide new insights into the structural basis of DNA recognition by PutA and reveal three‐dimensional structural details of the PutA dimer interface.
Interactions between plant growth and soil nutrient cycling under elevated CO2: a meta‐analysis
Authors: De GRAAFF MARIE‐ANNE , Van GROENIGEN KEES‐JAN , SIX JOHAN , HUNGATE BRUCE , Van KESSEL CHRIS
Published: September 2006

free air carbon dioxide enrichment (FACE) and open top chamber (OTC) studies are valuable tools for evaluating the impact of elevated atmospheric CO2 on nutrient cycling in terrestrial ecosystems. Using meta‐analytic techniques, we summarized the results of 117 studies on plant biomass production, soil organic matter dynamics and biological N2 fixation in FACE and OTC experiments. The objective of the analysis was to determine whether elevated CO2 alters nutrient cycling between plants and soil and if so, what the implications are for soil carbon (C) sequestration. Elevated CO2 stimulated gross N immobilization by 22%, whereas gross and net N mineralization rates remained unaffected. In addition, the soil C : N ratio and microbial N contents increased under elevated CO2 by 3.8% and 5.8%, respectively. Microbial C contents and soil respiration increased by 7.1% and 17.7%, respectively. Despite the stimulation of microbial activity, soil C input still caused soil C contents to increase by 1.2% yr−1. Namely, elevated CO2 stimulated overall above‐ and belowground plant biomass by 21.5% and 28.3%, respectively, thereby outweighing the increase in CO2 respiration. In addition, when comparing experiments under both low and high N availability, soil C contents (+2.2% yr−1) and above‐ and belowground plant growth (+20.1% and+33.7%) only increased under elevated CO2 in experiments receiving the high N treatments. Under low N availability, above‐ and belowground plant growth increased by only 8.8% and 14.6%, and soil C contents did not increase. Nitrogen fixation was stimulated by elevated CO2 only when additional nutrients were supplied. These results suggest that the main driver of soil C sequestration is soil C input through plant growth, which is strongly controlled by nutrient availability. In unfertilized ecosystems, microbial N immobilization enhances acclimation of plant growth to elevated CO2 in the long‐term. Therefore, increased soil C input and soil C sequestration under elevated CO2 can only be sustained in the long‐term when additional nutrients are supplied.
Levels of expression of complement regulatory proteins CD46, CD55 and CD59 on resting and activated human peripheral blood leucocytes
Authors: Christmas Stephen E. , De La Mata Espinosa Claudia T. , Halliday Deborah , Buxton Cheryl A. , Cummerson Joanne A. , Johnson Peter M.
Published: September 2006

The cell surface complement regulatory (CReg) proteins CD46, CD55 and CD59 are widely expressed on human lymphoid and non‐lymphoid cells. This study aimed to compare systematically levels of CReg expression by different leucocyte subsets and to determine whether levels were increased following activation in vitro. Levels of each CReg protein were similar on freshly isolated monocytes and all major lymphocyte subsets, except that CD4+ cells expressed significantly less CD46 than CD8+ cells (P < 0·05) while the reverse was observed for CD55 (P < 0·02). CD56+ cells, predominantly natural killer cells, expressed significantly lower levels of CD59 than T cells (P < 0·02). CD45RO+ cells had higher levels of surface CD46 and CD59, but lower levels of CD55, than CD45RO– cells (P < 0·02); CD25+ cells also expressed significantly less CD55 than CD25– cells (P < 0·002). Neutrophils expressed higher levels of CD59, but lower levels of CD55, than monocytes. Following activation with phytohaemagglutinin, CD46 was up‐regulated on all leucocyte subsets with the exception of CD56+ cells. Both CD55 and CD59 were also markedly up‐regulated on monocytes, and CD55 expression was greater on CD8+ than CD4+ cells following activation (P < 0·02). Lipopolysaccharide treatment did not significantly alter B‐cell expression of CReg proteins whereas CD55 and CD59, but not CD46, were significantly up‐regulated on monocytes (P < 0·02). These observations that CReg proteins are up‐regulated on certain activated leucocyte subsets indicate that levels would be increased following immune responses in vivo. This could enhance both protection against local complement activation at inflammatory sites and also the immunoregulatory properties of these leucocytes.
Leakage along apical root fillings with and without smear layer using two different leakage models: a two‐month longitudinal ex vivo study
Authors: Shemesh H. , Wu M.‐K. , Wesselink P. R.
Published: September 2006

Aim  To compare two different experimental models when measuring leakage along root fillings with or without smear layer.

Methodology  One hundred and twenty single‐rooted teeth were prepared to size 50 and allocated to two groups: fluid transport model (n = 60) and glucose penetration model (n = 60). The roots in each group were divided into three subgroups of 20 teeth each. Smear layer was left in place in group 1 but removed in groups 2 and 3. In groups 1 and 2 canals were filled with laterally compacted gutta‐percha cones and AH 26. Group 3 was laterally compacted with Resilon cones and Epiphany sealer. The coronal portion of the filling was removed to assure only 4 mm of filling remained in the canal. Leakage of glucose was evaluated by measuring its concentration once a week for a total period of 56 days using a glucose penetration model. Fluid transport was evaluated by measuring the movement of an air‐bubble using a fluid transport model, 1 and 8 weeks after canal filling. Differences between the groups in glucose concentrations and fluid transport were statistically analysed with the Kruskal–Wallis and the Mann–Whitney tests. The level of significance was set at α = 0.05.

Results  Glucose penetration was significantly different between the three groups after the first 8 days (P < 0.05). Resilon leaked the most throughout the experiment period. No significant difference (P > 0.05) existed between the two gutta‐percha groups at all time intervals (Mann–Whitney test). In the fluid transportation model, no statistically significant differences were observed between all three experimental groups (P > 0.05) at either 1 or 8 weeks after filling (Kruskal–Wallis test).

Conclusions  Under the conditions of this study, the glucose penetration model was more sensitive in detecting leakage along root fillings. Removing the smear layer before filling did not improve the sealing of the apical 4 mm of filling. Resilon allowed more glucose penetration but the same amount of fluid transport as the gutta‐percha root fillings.
Haemodynamic and metabolic effects of resuscitation with Ringer’s ethyl pyruvate in the acute phase of porcine endotoxaemic shock
Authors: Andersson A. , Fenhammar J. , Frithiof R. , Sollevi A. , Hjelmqvist H.
Published: September 2006

Background:  Ethyl pyruvate has been shown to possess anti‐inflammatory and free radical scavenging properties. However, the haemodynamic effects of ethyl pyruvate have not been studied in detail. We investigated the systemic, regional and microcirculatory haemodynamic and metabolic effects of resuscitation with Ringer’s ethyl pyruvate solution (REPS) vs. Ringer’s acetate (RA) in an acute model of porcine endotoxaemic shock.

Methods:  Fourteen anaesthetized pigs received an infusion of endotoxin that was increased stepwise over 30 min to a rate of 2.5 μg/kg/h. After 60 min of endotoxaemia, the animals were resuscitated with either ethyl pyruvate 40 mg/kg, given as REPS, or the equivalent volume of RA, administered over 10 min. Thereafter, an infusion of either ethyl pyruvate 40 mg/kg/h, given as REPS, or the equivalent volume of RA, was started, and the maintenance fluid was reduced so that the total amount of fluid given was kept constant. The experiment was terminated after 300 min of endotoxaemia.

Results:  Endotoxin infusion led to a hypodynamic state that was reversed by fluid resuscitation after 60 min. Progressive deterioration ensued and, after 300 min, all animals were again hypodynamic. No differences in response to treatment were found between the groups with regard to systemic haemodynamics, renal artery or portal vein flow or microcirculatory flow in the liver, kidney, ileal serosa or mucosa. Metabolic acidosis and increased arterial blood lactate developed in both groups, but, in the REPS group, the base excess was significantly lower from 150 min and the anion gap was significantly higher at 150 and 210 min.

Conclusion:  We could not demonstrate any difference between REPS and RA for resuscitation in this model of acute porcine endotoxaemic shock.
COMPUTER SIMULATIONS OF TRANSPORT THROUGH MEMBRANES: PASSIVE DIFFUSION, PORES, CHANNELS AND TRANSPORTERS
Authors: Tieleman D Peter
Published: September 2006

A key function of biological membranes is to provide mechanisms for the controlled transport of ions, nutrients, metabolites, peptides and proteins between a cell and its environment.

We are using computer simulations to study several processes involved in transport.

In model membranes, the distribution of small molecules can be accurately calculated; we are making progress towards understanding the factors that determine the partitioning behaviour in the inhomogeneous lipid environment, with implications for drug distribution, membrane protein folding and the energetics of voltage gating.

Lipid bilayers can be simulated at a scale that is sufficiently large to study significant defects, such as those caused by electroporation.

Computer simulations of complex membrane proteins, such as potassium channels and ATP‐binding cassette (ABC) transporters, can give detailed information about the atomistic dynamics that form the basis of ion transport, selectivity, conformational change and the molecular mechanism of ATP‐driven transport.

This is illustrated in the present review with recent simulation studies of the voltage‐gated potassium channel KvAP and the ABC transporter BtuCD.
PARADOXICALLY ENHANCED HEART TOLERANCE TO ISCHAEMIA IN TYPE 1 DIABETES AND ROLE OF INCREASED OSMOLARITY
Authors: Chen Hong , Shen Wei‐Li , Wang Xu‐Hui , Chen Hong‐Zhuan , Gu Jian‐Zhong , Fu Jie , Ni Ya‐Feng , Gao Ping‐Jin , Zhu Ding‐Liang , Higashino Hideaki
Published: September 2006

There is considerable controversy regarding the tolerance of diabetic hearts to ischaemia and the underlying mechanisms responsible for the increased heart tolerance to ischamia remain uncertain. In the present study, we observed, in vitro, type 1 diabetic heart responses to ischaemia and reperfusion at different degrees of hyperglycaemia. In addition, the possible role of increased osmolarity in cardioprotection due to hyperglycaemia was evaluated.

Hearts from 3 week streptozocin‐induced diabetic rats were isolated and perfused in a Langendorff apparatus and subjected to 30 min ischaemia and 30 min reperfusion. Cardiac function and the electrocardiogram were recorded. Myocardial content of osmolarity associated heat shock protein (hsp) 90, heme oxygenase (HO)‐1 and anti‐oxidant enzymes were determined in diabetic or hyperosmotic solution‐perfused hearts using western blot. The hsp90 inhibitor 17‐allylamino‐17‐demethoxygeldanamycin (17‐AAG; 2 × 10−7 mol/L) or the nitric oxide synthase (NOS) inhibitor Nω‐nitro‐l‐arginine methyl ester (1 × 10−5 mol/L) was added to the perfusate to observe the effects of hsp90 inhibition and hsp90‐associated endothelial NOS on ischaemic responses of diabetic hearts.

Compared with normal control rats, diabetic hearts with severe hyperglycaemia (blood glucose > 20 mmol/L) showed markedly improved postischaemic heart function with fewer reperfusion arrhythmias. Mild hyperglycaemia (< 12 mmol/L) exhibited no significant cardioprotection.

Elevated expression of hsp90 accompanied the enhanced resistance to ischaemia in diabetic hearts, which was abrogated by 17‐AAG. In the presence of the NOS inhibitor, heart function was preserved, whereas reperfusion arrhythmias were increased in diabetes. Diabetic hearts also had markedly elevated HO‐1 and catalase, with no significant change in superoxide dismutase. Hyperosmotic perfusion with glucose or mannitol also increased myocardial hsp90 and catalase.

The present findings reveal that heart resistance to ischaemia is increased in short‐term type 1 diabetes with severe hyperglycaemia. Elevated osmolarity caused by significant hyperglycaemia may contribute to the enhanced myocardial activity against oxidative injury during ischaemia and reperfusion.
HEPATOPROTECTIVE AND HYPOLIPIDAEMIC EFFECTS OF GLYCOPROTEIN ISOLATED FROM GARDENIA JASMINOIDES ELLIS IN MICE
Authors: Lee Sei‐Jung , Oh Phil‐Sun , Lim Kye‐Taek
Published: September 2006

The present study was performed to investigate the hepatoprotective and hypolipidaemic effects of a 27 kDa glycoprotein isolated from Gardenia jasminoides Ellis (GJE glycoprotein) in glucose/glucose oxidase (G/GO)‐treated BNL CL.2 cells, as well as in CCl4, Triton WR‐1339 and corn oil‐treated mice.

In G/GO‐treated BNL CL.2 cells, the results showed that GJE glycoprotein has an inhibitory effect on G/GO‐induced cytotoxicity and intracellular reactive oxygen species production. In addition, GJE glycoprotein has an anti‐oxidant effect against the lipid peroxidation process in the Fe2+/ascorbic acid system.

In CCl4 (1.0 mL/kg)‐treated mice, pretreatment with GJE glycoprotein (80 mg/kg) blocked lactate dehydrogenase release and the formation of thiobarbituric acid‐reactive substances. In addition, in these mice GJE resulted in increased nitric oxide production and the activation of anti‐oxidant enzymes, accompanied by the inhibition of the cytotoxic‐related signals hepatic cytochrome c, nuclear factor‐κB and activator protein‐1.

In both Triton WR‐1339 (400 mg/kg) and corn oil (1.0 g/kg)‐treated mice, pretreatment with GJE glycoprotein (80 mg/kg) lowered the levels of plasma lipoproteins (triglyceride, total cholesterol and low‐density lipoprotein).

On the basis of these results, we assume that GJE glycoprotein can ameliorate liver function, because it has hepatoprotective and hypolipidaemic activities.
DOCOSAHEXAENOIC ACID‐INDUCED PROTECTIVE EFFECT AGAINST IMPAIRED LEARNING IN AMYLOID β‐INFUSED RATS IS ASSOCIATED WITH INCREASED SYNAPTOSOMAL MEMBRANE FLUIDITY
Authors: Hashimoto Michio , Hossain Shahdat , Shimada Toshio , Shido Osamu
Published: September 2006

In the present study, we investigated the relationship between the docosahexaenoic acid (DHA)‐induced protection of learning deficit of amyloid β(1−40)‐infused Alzheimer's disease (AD) model rats and changes in synaptosomal plasma membrane fluidity of the cerebral cortex.

Synaptosomal membrane lateral and rotational fluidity were measured using pyrene excimer spectroscopy and fluorescence polarization of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH), respectively.

Avoidance learning ability, as assessed by a two‐way active avoidance paradigm, decreased significantly in the AD model rats.

Pyrene‐determined annular/non‐annular fluidity ratio and the DPH‐determined bulk fluidity of the synaptosomal plasma membrane decreased in the amyloid β(1−40)‐infused rats. Oral pre‐administration of DHA (300 mg/kg per day for 12 weeks) significantly increased both lateral and rotational fluidity.

The synaptosomal membrane DHA content increased and the cholesterol to phospholipid molar ratio and lipid peroxidation decreased.

The annular to non‐annular fluidity ratio of the synaptic plasma membrane was positively correlated with total avoidance learning.

The present results indicate that DHA‐induced alterations in synaptic plasma membrane fluidity may contribute to the synaptic plasma membrane‐related functions that constitute avoidance learning‐related memory in amyloid β(1−40)‐infused rats.
PROSTAGLANDINS, CAPSAICIN‐SENSITIVE SENSORY NERVES AND NEUTROPHIL INFILTRATION, BUT NOT NITRIC OXIDE, CONTRIBUTE TO COLD RESTRAINT STRESS‐INDUCED GASTRIC ADAPTATION IN RATS
Authors: Tan Ruken , Bülbül Mehmet , Öngüt Gözde , Tosun Özgür , İzgüt‐Uysal V Nimet
Published: September 2006

The aim of the present study was to determine the role of prostaglandins (PG), nitric oxide (NO) and capsaicin‐sensitive sensory nerves in neutrophil infiltration in gastric adaptation to cold restraint stress in rats.

Wistar rats were exposed to single or repeated cold restraint stress for 3.5 h every other day for up to 4 days. Prior to repeated stress, rats were pretreated with NG‐nitro‐l‐arginine methyl ester (l‐NAME; 10 mg/kg, s.c.), indomethacin (10 mg/kg, s.c.) or capsaicin (125 mg/kg, s.c.). The extent of gastric mucosal lesions was evaluated histologically and myeloproxidase (MPO) activity, PGE2, NO and calcitonin gene‐related peptide (CGRP) levels were measured in gastric tissue.

Cold restraint stress produced haemorrhagic lesions and reduced PGE2 and CGRP levels in the stomach, with an increase in MPO activity and NO levels. Repeated stress insults reduced stress‐induced gastric damage, NO production and MPO activity, with an increase in PGE2 and CGRP levels compared with rats exposed to single cold restraint stress. Adaptation to cold restraint stress was prevented by indomethacin and capsaicin pretreatment, but not by l‐NAME.

We conclude that the stomach has the ability to adapt to repeated exposure to cold restraint stress and that the adaptation, via inhibition of neutrophil infiltration, is mediated, at least in part, by endogenous PG and CGRP.
INTRARENAL OXYGEN IN DIABETES AND A POSSIBLE LINK TO DIABETIC NEPHROPATHY
Authors: Palm Fredrik
Published: September 2006

Diabetic nephropathy is a major cause of morbidity and mortality. The exact mechanism mediating the negative influence of hyperglycaemia on renal function remains unclear, although several hypotheses have been postulated. The cellular mechanisms include glucose‐induced excessive formation of reactive oxygen species, increased glucose flux through the polyol pathway and formation of advanced glycation end‐products. The renal effects in vivo of each and every one of these mechanisms are even less clear. However, there is growing evidence that hyperglycaemia results in altered renal oxygen metabolism and decreased renal oxygen tension and that these changes are linked to altered kidney function.

Clinical data regarding renal oxygen metabolism and oxygen tension are currently rudimentary and our present understanding regarding renal oxygenation during diabetes is predominantly derived from data obtained from animal models of experimental diabetic nephropathy.

This review will present recent findings regarding the link between hyperglycaemia and diabetes‐induced alterations in renal oxygen metabolism and renal oxygen availability.

A possible link between reduced renal oxygen tension and the development of diabetic nephropathy includes increased polyol pathway activity and oxidative stress, which result in decreased renal oxygenation and subsequent activation of hypoxia‐inducible factors. This initiates increased gene expression of numerous genes known to be involved in development of diabetic nephropathy.
HYPOXIA‐INDUCED ERYTHROPOIETIN PRODUCTION: A PARADIGM FOR OXYGEN‐REGULATED GENE EXPRESSION
Authors: Stockmann Christian , Fandrey Joachim
Published: September 2006

The mechanisms controlling the expression of the gene encoding for the hormone erythropoietin (EPO) are exemplary for oxygen‐regulated gene expression. In humans and other mammals, hypoxia modulates EPO levels by increasing expression of the EPO gene. An association between polycythaemia and people living at high altitudes was first reported more than 100 years ago.

Since the identification of EPO as the humoral regulator of red blood cell production and the cloning of the EPO gene, considerable progress has been made in understanding the regulation of EPO gene expression. This has finally led to the identification of a widespread cellular oxygen‐sensing mechanism. Central to this mechanism is the transcription factor complex hypoxia‐inducible factor (HIF)‐1.

The abundance and activity of HIF‐1, a heterodimer of an α‐ and β‐subunit, is predominantly regulated by oxygen‐dependent post‐translational hydroxylation of the α‐subunit. Non‐heme ferrous iron containing hydroxylases use dioxygen and 2‐oxoglutarate to specifically target proline and an asparagine residue in HIF‐1α. As such, the three prolyl hydroxylases (prolyl hydroxylase domain‐containing protein (PHD) 1, PHD2 and PHD3) and the asparagyl hydroxylase (factor inhibiting HIF (FIH)‐1) act as cellular oxygen sensors. In addition to erythropoiesis, HIF‐1 regulates a broad range of physiologically relevant genes involved in angiogenesis, apoptosis, vasomotor control and energy metabolism. Therefore, the HIF system is implicated in the pathophysiology of many human diseases.

In addition to the tight regulation by oxygen tension, temporal and tissue‐specific signals limit expression of the EPO gene primarily to the fetal liver and the adult kidney.
INTRARENAL OXYGENATION IN CHRONIC RENAL FAILURE
Authors: Norman Jill T , Fine Leon G
Published: September 2006

In chronic renal failure (CRF), renal impairment correlates with tubulointerstitial fibrosis characterized by inflammation, interstitial expansion with accumulation of extracellular matrix (ECM), tubular atrophy and vascular obliteration. Tubulointerstitial injury subsequent to glomerular sclerosis may be induced by proteinuria, leakage of glomerular filtrate or injury to the post‐glomerular peritubular capillaries (hypoxia).

In vivo data in animal models suggest that CRF is associated with hypoxia, with the decline in renal Po2 preceding ECM accumulation.

Chronic renal failure is characterized by loss of microvascular profiles but, in the absence of microvascular obliteration, hypoxia can occur by a variety of complementary mechanisms, including anaemia, decreased capillary flow, increased vasoconstriction, increased metabolic demand and increased diffusion distances due to ECM deposition.

Hypoxia regulates a wide array of genes, including many fibrogenic factors. Hypoxia‐inducible factors (HIF) are the major, but not the sole, transcriptional regulators in the hypoxic response.

In CRF, hypoxia may play a role in the sustained inflammatory response.

In vitro studies in tubulointerstitial cells suggest that hypoxia can induce profibrogenic changes in proximal tubular epithelial cells and interstitial fibroblasts consistent with changes observed in CRF in vivo. The effect of hypoxia on renal microvascular cells warrants investigation.

Hypoxia may play a role in the recruitment, retention and differentiation of circulating progenitor cells to the kidney contributing to the disease process and may also affect intrinsic stem cell populations.

Chronic hypoxia in CRF fails to induce a sustained angiogenic response.

Therapeutic manipulation of the hypoxic response may be of benefit in slowing progression of CRF. Potential therapies include correction of anaemia, inhibition of the renin–angiotensin system, administration of exogenous pro‐angiogenic factors to protect the microvasculature, activation of HIF and hypoxia‐mediated targeting of engineered progenitor cells.
INTRARENAL OXYGEN AND HYPERTENSION
Authors: Welch William J
Published: September 2006

The kidney has a unique environment that results in relatively low tissue oxygen tension (Po2). However, recent studies have shown that renal hypoxia is more severe during hypertension and may reflect changes in the way O2 is used. The present review summarizes studies that explore the relationship between renal oxygen tension (Po2), oxygen consumption and hypertension.

More recent studies suggest that oxidative stress accompanying hypertension, rather than the elevated blood pressure per se reduces Po2. The Po2 in various sections of the kidney often reflects the level of oxygen consumption, which varies depending on the sites of Na+ reabsorption, a process that consumes nearly 90% of total renal oxygen.

The efficient use of oxygen for the transport of Na+ in the kidney is reduced during hypertension, which may contribute to the resulting hypoxia. Conversely, the defect in renal oxygen usage due to oxidative stress may exacerbate hypertension in animal models. The goal of many of these studies is to determine the impact of renal hypoxia in the generation of hypertension.
Ecological studies to assess the efficacy of biological control on populations of alligator weed and lippia
Authors: Schooler Shon , Clech‐Goods Céline , Julien Mic
Published: September 2006

Abstract  The risk of non‐target effects from biological control agents can be reduced if we can better identify effective agents prior to release. Introducing only those agents with high potential for effective control will reduce the number of agents released and reduce the probability of both direct and indirect non‐target impacts. Identifying effective agents requires understanding the roles that resources, disturbances and herbivory play in regulating plant populations under natural field conditions. Here we propose a series of experiments that will contrast the mechanisms of population regulation of two invasive wetland plants, alligator weed (Alternanthera philoxeroides) and lippia (Phyla canescens), with native congener species, Alternanthera denticulata and Phyla nodiflora. We hypothesise that the native plants will have greater growth rates when nutrients are low and herbivores are present, whereas the introduced plants will exhibit greater growth rates when nutrients are high and herbivores are absent.
Maximising the contribution of native‐range studies towards the identification and prioritisation of weed biocontrol agents
Authors: Goolsby John A , Van Klinken Rieks D , Palmer William A
Published: September 2006

Abstract  Effective study in the native range to identify potential agents underpins all efforts in classical biological control of weeds. Good agents that demonstrate both a high degree of host specificity and the potential to be damaging are a very limited resource and must therefore be carefully studied and considered. The overseas component is often operationally difficult and expensive but can contribute considerably more than a list of herbivores attacking a particular target. While the principles underlying this foreign component have been understood for some time, recently developed technologies and methods can make very significant contributions to foreign studies. Molecular and genetic characterisations of both target weed and agent organism can be increasingly employed to more accurately define the identity and phylogeny of them. Climate matching and modelling software is now available and can be utilised to better select agents for particular regions of concern. Relational databases can store collection information for analysis and future enquiry while quantification of sampling effort, employment of statistical survey methods and analysis by techniques such as rarefaction curves contribute to efficient and effective searching. Obtaining good and timely identifications for discovered agent organisms is perhaps the most serious issue confronting the modern explorer. The diminishing numbers of specialist taxonomists employed at the major museums while international and national protocols demand higher standards of identity exacerbates the issue. Genetic barcoding may provide a very useful tool to overcome this problem. Native‐range work also offers under‐exploited opportunities for contributing towards predicting safety, abundance and efficacy of potential agents in their target environment.
Selection of biological control agents for bridal creeper: a retrospective review
Authors: Morin Louise , Edwards Penelope B
Published: September 2006

Abstract  We reviewed in retrospect the selection process of agents for the biological control of bridal creeper (Asparagus asparagoides) in Australia. Selection of agents was facilitated by first investing resources, mostly in South Africa, to clarify identification of the target weed, locate most suitable areas to search for natural enemies, make preliminary observations on phenology, host range and impact of natural enemies and experimentally demonstrate indirect impact of a foliage feeder on below‐ground biomass of bridal creeper. Although only limited climate modelling was performed to predict abundance of prioritised agents in Australia, their widespread distribution in South Africa was a good indication that they were likely to establish. No attempts were made to predict possible levels of parasitism that could be encountered in Australia and no formal assessment was undertaken to decide in what order prioritised agents should be released. Three of the four agents prioritised have now been released in Australia. The rust fungus Puccinia myrsiphylli (Thüm.) G. Winter and leafhopper Zygina sp. have widely established and have already demonstrated their capacity to reduce significantly density of bridal creeper populations. It is still too early to determine the contribution that the third agent released, the Crioceris sp. leaf beetle, will make to the program.
Use of CLIMEX modelling to identify prospective areas for exploration to find new biological control agents for prickly acacia
Authors: Senaratne K A D Wilmot , Palmer William A , Sutherst Robert W
Published: September 2006

Abstract  Selection of biocontrol agents that are adapted to the climates in areas of intended release demands a thorough analysis of the climates of the source and release sites. We present a case study that demonstrates how use of the CLIMEX software can improve decision making in relation to the identification of prospective areas for exploration for agents to control the woody weed, prickly acacia Acacia nilotica ssp. indica in the arid areas of north Queensland.
A systematic approach to biological control agent exploration and prioritisation for prickly acacia (Acacia nilotica ssp. indica)
Authors: Dhileepan K , Senaratne K A D Wilmot , Raghu S
Published: September 2006

Abstract  Agent selection for prickly acacia has been largely dictated by logistics and host specificity. Given that detailed ecological information is available on this species in Australia, we propose that it is possible to select agents based on agent efficacy and desired impact on prickly acacia demography. We propose to use the ‘plant genotype’ and ‘climatic’ similarities as filters to identify areas for future agent exploration; and plant response to herbivory and field host range as ‘predictive’ filters for agent prioritisation. Adopting such a systematic method that incorporates knowledge from plant population ecology and plant–herbivore interactions makes agent selection decisions explicit and allow more rigorous evaluations of agent performance and better understanding of success and failure of agents in weed biological control.
Sources of Bias in the Recall of Self‐Generated Data: The Role of Anchoring1
Authors: Fraser Stuart , Greene Francis J. , Mole Kevin F.
Published: September 2006

This study examines two issues. First, we assess the reliability of employment data self‐generated by respondents using a survey panel of 280 firms surveyed in 1999 and again in 2002. Our results show that there is a close correlation between self‐generated and archival secondary data. Second, we test for bias in the recall of previous years' employment levels and the sources of such bias. We assess three reasons for recall bias: respondent‐level factors; firm‐level factors; and anchoring. Our regression results indicate that: owners and new respondents; those in firms that changed legal status and/or location; those in smaller firms; and those in growing or declining firms were biased in their recall of prior employment. In addition, growing firms tended to underestimate their growth, which points to anchoring as an explanation for these biases. These biases imply that we have to be careful in delineating performance measures and cautious about how we interpret self‐generated managerial information.
1. Another Look at the Stratification of Educational Transitions: The Logistic Response Model with Partial Proportionality Constraints
Authors: Hauser Robert M. , Andrew Megan
Published: September 2006

In this paper we reanalyze Robert D. Mare's highly influential work on educational transitions among American men born in the first half of the 20th century. Contrary to previous belief Mare found that the effects of socioeconomic background variables decline regularly across educational transitions in conditional logistic regression analyses. We have reconfirmed Mare's findings and tested them by introducing a modified logistic response model that constrains selected social background effects to vary proportionally across educational transitions. We refer to our preferred model as the logistic response model with partial proportionality constraints (LRPPC). The model can easily be estimated in Stata or using other standard statistical software. Partial proportionality constraints may also prove useful in interpopulation comparisons based on other linear models.