bluuebunny/crossref_metadata_2025 huggingface dataset:
Readmission to a surgical intensive care unit: incidence, outcome and risk factors
Authors: Kaben Axel , Corrêa Fabiano , Reinhart Konrad , Settmacher Utz , Gummert Jan , Kalff Rolf , Sakr Yasser
Published: October 2008

Introduction

We investigated the incidence of, outcome from and possible risk factors for readmission to the surgical intensive care unit (ICU) at Friedrich Schiller University Hospital, Jena, Germany.

Methods

We conducted an analysis of prospectively collected data from all patients admitted to the postoperative ICU between September 2004 and July 2006.

Results

Of 3169 patients admitted to the ICU during the study period, 2852 were discharged to the hospital floor and these patients made up the study group (1828 male (64.1%), mean patient age 62 years). The readmission rate was 13.4% (n = 381): 314 (82.4%) were readmitted once, 39 (10.2%) were readmitted twice and 28 (7.3%) were readmitted more than twice. The first readmission to the ICU occurred within a median of seven days (range 5 to 14 days). Patients who were readmitted to the ICU had a higher simplified acute physiology II score (37 +/- 16 versus 33 +/- 16; p < 0.001) and sequential organ failure score (6 +/- 3 versus 5 +/- 3; p = 0.001) on initial admission to the ICU than those who were not readmitted. In-hospital mortality was significantly higher in patients readmitted to the ICU (17.1% versus 2.9%; p < 0.001) than in other patients. In a multivariate analysis, age (odds ratio (OR) = 1.13 per 10 years; 95% confidence interval (CI) = 1.03 to 1.24; p = 0.04), maximum sequential organ failure score (OR = 1.04 per point; 95% CI = 1.01 to 1.08; p = 0.04) and C-reactive protein levels on the day of discharge to the hospital floor (OR = 1.02; 95% CI = 1.01 to 1.04; p = 0.035) were independently associated with a higher risk of readmission to the ICU.

Conclusions

In this group of surgical ICU patients, readmission to the ICU was associated with a more than five-fold increase in hospital mortality. Older age, higher maximum sequential organ failure score and higher C-reactive protein levels on the day of discharge to the hospital floor were independently associated with a higher risk of readmission to the ICU.
Tamoxifen Use and Osteoporotic Fracture Risk: A Population-Based Analysis
Authors: Cooke Andrew L. , Metge Colleen , Lix Lisa , Prior Heather J. , Leslie William D.
Published: October 2008

Purpose

Although tamoxifen has been shown to increase bone mineral density in clinical trials, it is less clear whether this significantly affects fracture rates. Even fewer data are available on skeletal outcomes when tamoxifen is used outside of the context of a clinical trial. A population-based case-control study was undertaken to determine whether tamoxifen use is associated with osteoporotic fractures in routine clinical practice.

Patients and Methods

Population-based administrative data for the Province of Manitoba, Canada, were examined for tamoxifen use and nontraumatic fracture codes in women 50 years of age or older. Women with osteoporotic fractures (vertebral, wrist or hip; n = 11,096) from 1996 to 2004 were each compared with three controls without fracture, matched for age, ethnicity, and comorbidity (n = 33,209). Tamoxifen use was classified as never, past use, or current use.

Results

Lower osteoporotic fracture rates were associated with current tamoxifen use (univariate odds ratio [OR] = 0.68; 95% CI, 0.55 to 0.84). After controlling for demographic and medical diagnoses known to affect fracture risk, current use was associated with a significantly reduced overall osteoporotic fracture risk (adjusted OR = 0.68; 95% CI, 0.55 to 0.88) and of hip fractures (adjusted OR = 0.47; 95% CI, 0.28 to 0.77). Neither recent nor remote past tamoxifen use was associated with reduced osteoporotic fracture risk. Breast cancer was not independently associated with osteoporotic fractures (adjusted OR = 0.95; 95% CI, 0.81 to 1.12).

Conclusion

In a population-based case-control study, current tamoxifen use was associated with a substantial reduction in osteoporotic fractures.
Reduction and Cessation of Cigarette Smoking and Risk of Cancer: A Cohort Study of Korean Men
Authors: Song Yun-Mi , Sung Joohon , Cho Hong-Jun
Published: October 2008

Purpose

Reducing cigarette smoking has been proposed as a method of harm reduction. The effect of smoking reduction on cancer risk has not been studied in Asian populations.

Patients and Methods

A total of 479,156 Korean men, age 30 to 58 years, were stratified into nine groups based on smoking status in 1990 and 1992. From 1992 to 2003, patients were observed and tested for the occurrence of cancer.

Results

There was no association between smoking reduction and risk of all cancers. However, the risk of smoking-related cancers tended to decrease, though not significantly, when heavy smokers (≥ 20 cigarettes/d) became moderate smokers (10 to 19 cigarettes/d), with a hazard ratio (HR) of 0.91 (95% CI, 0.82 to 1.02). For lung cancer, patients who reduced from heavy to moderate smoking and from heavy to light smoking (< 10 cigarettes/d) had significantly decreased risks based on multivariable-adjusted HRs (HR = 0.72, 95% CI, 0.49 to 0.89; HR = 0.63, 95% CI, 0.46 to 0.84, respectively). Study participants who never smoked, sustained ex-smokers, and quitters had lower risks for all cancers, smoking-related cancers, and lung cancer in a dose-response manner as compared with heavy smokers.

Conclusion

Smoking reduction was associated with a significant decrease in the risk of lung cancer, but the size of risk reduction was disproportionately smaller than that expected from the reduced amount of cigarette consumption. Although smoking cessation should be the cornerstone of preventing smoking-related cancers, smoking reduction could be considered as a strategy to supplement smoking cessation for those who are unable to quit smoking immediately.
Glycerolipid Metabolism and Signaling in Health and Disease
Authors: Prentki Marc , Madiraju S. R. Murthy
Published: October 2008

Maintenance of body temperature is achieved partly by modulating lipolysis by a network of complex regulatory mechanisms. Lipolysis is an integral part of the glycerolipid/free fatty acid (GL/FFA) cycle, which is the focus of this review, and we discuss the significance of this pathway in the regulation of many physiological processes besides thermogenesis.

GL/FFA cycle is referred to as a “futile” cycle because it involves continuous formation and hydrolysis of GL with the release of heat, at the expense of ATP. However, we present evidence underscoring the “vital” cellular signaling roles of the GL/FFA cycle for many biological processes. Probably because of its importance in many cellular functions, GL/FFA cycling is under stringent control and is organized as several composite short substrate/product cycles where forward and backward reactions are catalyzed by separate enzymes. We believe that the renaissance of the GL/FFA cycle is timely, considering the emerging view that many of the neutral lipids are in fact key signaling molecules whose production is closely linked to GL/FFA cycling processes.

The evidence supporting the view that alterations in GL/FFA cycling are involved in the pathogenesis of “fatal” conditions such as obesity, type 2 diabetes, and cancer is discussed. We also review the different enzymatic and transport steps that encompass the GL/FFA cycle leading to the generation of several metabolic signals possibly implicated in the regulation of biological processes ranging from energy homeostasis, insulin secretion and appetite control to aging and longevity. Finally, we present a perspective of the possible therapeutic implications of targeting this cycling.
Thyroid Function and Structure Are Affected in Childhood Obesity
Authors: Radetti Giorgio , Kleon Wolfgang , Buzi Fabio , Crivellaro Claudio , Pappalardo Lucia , di Iorgi Natascia , Maghnie Mohamad
Published: October 2008

Objective: Alterations in thyroid function are reported in obesity, although no relevant data exist on the thyroid structure of these patients and the frequency of autoimmunity. The aim of our study was to evaluate the involvement of the thyroid gland in a large group of obese children.

Design: This was a cross-sectional study.

Methods: The study was conducted between March 2004 and December 2007 in 186 overweight and obese children. In all subjects, serum free T3, free T4, TSH, antithyroid antibodies, and a thyroid ultrasound were assessed. A total ot 40 healthy children matched for age and of normal weight for height served as controls.

Results: A total of 23 children (12.4%) showed antithyroid antibodies and an ultrasound pattern suggestive of Hashimoto’s thyroiditis (group A). Of them, 20 (10.8%) showed antithyroid antibodies and normal ultrasound (group B). A total of 70 subjects (37.6%) showed absent antithyroid antibodies and an ultrasound pattern suggestive of Hashimoto’s thyroiditis (group C), and 73 children (39.2%) showed no thyroid antibodies with normal ultrasound (group D). TSH was higher in groups A and C compared with groups B and C, and controls (P < 0.05). Mean free T4 was lower in group B (P < 0.05) than in controls, whereas free T3 was higher in group C than in controls (P < 0.05). TSH and body mass index sd scores were significantly correlated in group C (P < 0.001), and TSH was also significantly associated with the degree of thyroid structure alterations (P < 0.05).

Conclusion: Obese children frequently show alterations of thyroid structure and function that are not completely explained by the presence of an autoimmune involvement.
The Majority of Adrenocorticotropin Receptor (Melanocortin 2 Receptor) Mutations Found in Familial Glucocorticoid Deficiency Type 1 Lead to Defective Trafficking of the Receptor to the Cell Surface
Authors: Chung T. T. , Webb T. R. , Chan L. F. , Cooray S. N. , Metherell L. A. , King P. J. , Chapple J. P. , Clark A. J. L.
Published: October 2008

Context: There are at least 24 missense, nonconservative mutations found in the ACTH receptor [melanocortin 2 receptor (MC2R)] that have been associated with the autosomal recessive disease familial glucocorticoid deficiency (FGD) type 1. The characterization of these mutations has been hindered by difficulties in establishing a functional heterologous cell transfection system for MC2R. Recently, the melanocortin 2 receptor accessory protein (MRAP) was identified as essential for the trafficking of MC2R to the cell surface; therefore, a functional characterization of MC2R mutations is now possible.

Objective: Our objective was to elucidate the molecular mechanisms responsible for defective MC2R function in FGD.

Methods: Stable cell lines expressing human MRAPα were established and transiently transfected with wild-type or mutant MC2R. Functional characterization of mutant MC2R was performed using a cell surface expression assay, a cAMP reporter assay, confocal microscopy, and coimmunoprecipitation of MRAPα.

Results: Two thirds of all MC2R mutations had a significant reduction in cell surface trafficking, even though MRAPα interacted with all mutants. Analysis of those mutant receptors that reached the cell surface indicated that four of six failed to signal, after stimulation with ACTH.

Conclusion: The majority of MC2R mutations found in FGD fail to function because they fail to traffic to the cell surface.
Bartolomé García Correa and the Politics of Maya Identity in Postrevolutionary Yucatán, 1911-1933
Authors: Fallaw Ben
Published: October 2008

This political biography explores the ambiguous ethnicity of Bartolomé García Correa (1893-1978), the first person of Maya descent to govern Yucatán since the Spanish Conquest. Son of an upwardly mobile, Maya-speaking, afromestizo middle-class family, García Correa's normal education and ties to the Church set him on a path to socioeconomic success in the autumn of the Porfiriato. During the Mexican Revolution, he reinvented himself as a revolutionary politico and embraced indigenism. Using the latter, he could celebrate the Maya in the abstract while urging acculturation. Indeed, he represented himself as an authority on the Maya and as a model outcome of indigenista assimilation. Part revolutionary cacique (or boss), part ethnic broker, he used his mastery of Yucatec Maya and populist style to parry demands from below and to accommodate the new political and old economic elites. Still, he resisted self-identifying as Maya, which would have compromised his hard-won mestizo status. His rise culminated in the governorship in 1930. White enemies' attacks on García Correa's Maya background helped undo his administration, although his influence over postrevolutionary politics endured for decades.
Expression of pro- and anti-angiogenic isoforms of VEGF is differentially regulated by splicing and growth factors
Authors: Nowak Dawid G. , Woolard Jeanette , Amin Elianna Mohamed , Konopatskaya Olga , Saleem Moin A. , Churchill Amanda J. , Ladomery Michael R. , Harper Steven J. , Bates David O.
Published: October 2008

Vascular endothelial growth factor A (VEGFA; hereafter referred to as VEGF) is a key regulator of physiological and pathological angiogenesis. Two families of VEGF isoforms are generated by alternate splice-site selection in the terminal exon. Proximal splice-site selection (PSS) in exon 8 results in pro-angiogenic VEGFxxx isoforms (xxx is the number of amino acids), whereas distal splice-site selection (DSS) results in anti-angiogenic VEGFxxxb isoforms. To investigate control of PSS and DSS, we investigated the regulation of isoform expression by extracellular growth factor administration and intracellular splicing factors. In primary epithelial cells VEGFxxxb formed the majority of VEGF isoforms (74%). IGF1, and TNFα treatment favoured PSS (increasing VEGFxxx) whereas TGFβ1 favoured DSS, increasing VEGFxxxb levels. TGFβ1 induced DSS selection was prevented by inhibition of p38 MAPK and the Clk/sty (CDC-like kinase, CLK1) splicing factor kinase family, but not ERK1/2. Clk phosphorylates SR protein splicing factors ASF/SF2, SRp40 and SRp55. To determine whether SR splicing factors alter VEGF splicing, they were overexpressed in epithelial cells, and VEGF isoform production assessed. ASF/SF2, and SRp40 both favoured PSS, whereas SRp55 upregulated VEGFxxxb (DSS) isoforms relative to VEGFxxx. SRp55 knockdown reduced expression of VEGF165b. Moreover, SRp55 bound to a 35 nucleotide region of the 3′UTR immediately downstream of the stop codon in exon 8b. These results identify regulation of splicing by growth and splice factors as a key event in determining the relative pro-versus anti-angiogenic expression of VEGF isoforms, and suggest that p38 MAPK-Clk/sty kinases are responsible for the TGFβ1-induced DSS selection, and identify SRp55 as a key regulatory splice factor.
Identification of ANKRD11 as a p53 coactivator
Authors: Neilsen Paul M. , Cheney Kelly M. , Li Chia-Wei , Chen J. Don , Cawrse Jacqueline E. , Schulz Renée B. , Powell Jason A. , Kumar Raman , Callen David F.
Published: October 2008

The ability of p53 to act as a transcription factor is critical for its function as a tumor suppressor. Ankyrin repeat domain 11, ANKRD11 (also known as ANR11 or ANCO1), was found to be a novel p53-interacting protein that enhanced the transcriptional activity of p53. ANKRD11 expression was shown to be downregulated in breast cancer cell lines. Restoration of ANKRD11 expression in MCF-7 (wild-type p53) and MDA-MB-468 (p53R273H mutant) cells suppressed their proliferative and clonogenic properties through enhancement of CDKN1A (p21waf1/CIP1) expression. ShRNA-mediated silencing of ANKRD11 expression reduced the ability of p53 to activate CDKN1A expression. ANKRD11 was shown to associate with the p53 acetyltransferases and cofactors, P/CAF and hADA3. Exogenous ANKRD11 expression enhanced the levels of acetylated p53 in both MCF-7 and MDA-MB-468 cells. ANKRD11 enhanced the DNA-binding properties of mutant p53R273H to the CDKN1A promoter, suggesting that ANKRD11 can mediate the restoration of normal p53 function in some cancer-related p53 mutations. In addition, ANKRD11 itself was found to be a novel p53 target gene. These findings demonstrate a role for ANKRD11 as a p53 coactivator and suggest the involvement of ANKRD11 in a regulatory feedback loop with p53.
Hypermethylation of yeast telomerase RNA by the snRNA and snoRNA methyltransferase Tgs1
Authors: Franke Jacqueline , Gehlen Jessica , Ehrenhofer-Murray Ann E.
Published: October 2008

Telomerase in Saccharomyces cerevisiae consists of three protein subunits and the RNA moiety TLC1, which together ensure the complete replication of chromosome ends. TLC1 shares several features with snRNA, among them the presence of a trimethylguanosine (m3G) cap structure at the 5′ end of the RNA. Here, we report that the yeast snRNA and snoRNA methyltransferase Tgs1 is responsible for TLC1 m3G cap formation. The absence of Tgs1 caused changes in telomere length and structure, improved telomeric silencing and stabilized telomeric recombination. Genetic analyses implicated a role for the TLC1 m3G cap in the coordination between telomerase and DNA polymerase for end replication. Furthermore, tgs1Δ cells displayed a shortened replicative lifespan, suggesting that the loss of the m3G cap of TLC1 causes premature aging.
Light-dependent magnetoreception: orientation behaviour of migratory birds under dim red light
Authors: Wiltschko Roswitha , Munro Ursula , Ford Hugh , Stapput Katrin , Wiltschko Wolfgang
Published: October 2008

Magnetic compass orientation in migratory birds has been shown to be based on radical pair processes and to require light from the short wavelength part of the spectrum up to 565 nm Green. Under dim red light of 645 nm wavelength and 1 mW m–2 intensity, Australian silvereyes and European robins showed a westerly tendency that did not change between spring and autumn, identifying it as a `fixed direction' response. A thorough analysis revealed that this orientation did not involve the inclination compass, but was a response based on the polarity of the magnetic field. Furthermore, in contrast to the orientation under short-wavelength light, it could be disrupted by local anaesthesia of the upper beak where iron-containing receptors are located, indicating that it is controlled by these receptors. The similarity of the response under dim red light to the response in total darkness suggests that the two responses may be identical. These findings indicate that the observed `fixed direction' response under dim red light is fundamentally different from the normal compass orientation, which is based on radical pair processes.
The influence of oxygen and high-energy phosphate diffusion on metabolic scaling in three species of tail-flipping crustaceans
Authors: Jimenez Ana Gabriela , Locke Bruce R. , Kinsey Stephen T.
Published: October 2008

We examined the influence of intracellular diffusion of O2 and high-energy phosphate (HEP) molecules on the scaling with body mass of the post-exercise whole-animal rate of O2 consumption(V̇O2) and muscle arginine phosphate (AP) resynthesis rate, as well as muscle citrate synthase(CS) activity, in three groups of tail-flipping crustaceans. Two size classes in each of three taxa (Palaemonetes pugio, Penaeus spp. and Panulirus argus) were examined that together encompassed a 27,000-fold range in mean body mass. In all species, muscle fiber size increased with body mass and ranged in diameter from 70±1.5 to 210±8.8 μm. Thus, intracellular diffusive path lengths for O2 and HEP molecules were greater in larger animals. The body mass scaling exponent, b, for post-tail flipping V̇O2(b=–0.21) was not similar to that for the initial rate of AP resynthesis (b=–0.12), which in turn was different from that of CS activity (b=0.09). We developed a mathematical reaction–diffusion model that allowed an examination of the influence of O2 and HEP diffusion on the observed rate of aerobic flux in muscle. These analyses revealed that diffusion limitation was minimal under most conditions, suggesting that diffusion might act on the evolution of fiber design but usually does not directly limit aerobic flux. However, both within and between species, fibers were more diffusion limited as they grew larger,particularly when hemolymph PO2 was low, which might explain some of the divergence in the scaling exponents of muscle aerobic capacity and muscle aerobic flux.
Ionic determinants of pH of acidic compartments under hypertonic conditions in trout hepatocytes
Authors: Ahmed Khaled H. , Pelster Bernd
Published: October 2008

Exposure of trout hepatocytes to hypertonicity induced a decrease in acridine orange (AO) fluorescence, indicating a corresponding decrease in pH inside the lumen of acidic compartments (pHL). Pre-exposure of cells to the specific V-ATPase inhibitor bafilomycin A1 (0.3 μmol l–1) increased AO fluorescence – unmasking H+ leaks under steady-state conditions – and partially removed the hypertonicity-induced pHL decrease. The sustainability of the luminal acidification, but not the acidification itself, appeared to depend on a low K+ and a high Cl– conductance under hypertonic conditions. Increasing K+ conductance using the specific ionophore valinomycin (10 μmol l–1) or removal of extracellular Cl– after an instant drop in AO fluorescence resulted in a reversal of luminal acidity. The alkalinization measured under hypertonic conditions in the absence of Cl– was largely attenuated when cells were bathed in HCO3–-free medium, signifying the possible presence of Cl–/HCO3– exchange. Under steady-state conditions, while a slight and brief pHL increase was measured upon exposure of cells to valinomycin, Cl– removal,unexpectedly, induced a decrease in pHL, indicating a role for extracellular Cl– in limiting luminal acidification. This was confirmed by the substantial pHL decrease measured upon exposure of cells to the anion exchanger inhibitor SITS (0.5 mmol l–1). Furthermore, hypertonicity-induced acidification was still noticeable in the presence of SITS. On the other hand, the hypertonicity-induced acidification was significantly reduced in the absence of extracellular Na+ or Ca2+. However, BAPTA-AM induced an increase in steady-state pHL that was independent of V-ATPase inhibition. Moreover, the BAPTA-induced alkalinization was still apparent after depletion of intracellular Ca2+ using the Ca2+ ionophore A23187 in Ca2+-free medium. We conclude that pHL of trout hepatocytes is sensitive to hypertonicity and ionic determinants of hypertonicity. Thus, changes in pHL should be considered when studying pH adaptations to hypertonic stress.
Integrating the determinants of suction feeding performance in centrarchid fishes
Authors: Holzman Roi , Day Steven W. , Mehta Rita S. , Wainwright Peter C.
Published: October 2008

When suction-feeding vertebrates expand their buccal cavity to draw water into their mouth, they also exert a hydrodynamic force on their prey. This force is key to strike success, directly countering forces exerted by escaping or clinging prey. While the ability to produce high flow accelerations in front of the mouth is central to the predator's ability to exert high forces on the prey, several mechanisms can contribute to the disparity between the potential and realized performance through their effect on flow and acceleration as experienced by the prey. In the present study, we test how interspecific variation in gape size, mouth displacement speed and the fish's ability to locate prey at the optimal position affect variation in the force exerted on attached prey. We directly measured these forces by allowing bluegill sunfish and largemouth bass to strike at ghost shrimp tethered to a load cell that recorded force at 5000 Hz, while synchronously recording strikes with a 500 Hz video. Strike kinematics of largemouth bass were slower than that of bluegill, as were estimated flow speeds and the force exerted on the prey. This difference in force persisted after taking into account the faster suction flows and accelerations of bluegill, and was only accounted for by considering interspecific differences in gape size, mouth displacement speed and fish's ability to locate the prey at the optimal position. The contribution to interspecific differences in the force exerted on the prey was estimated to be 42% for flow speed, 25% for strike efficiency, 3% for gape size and 30% for mouth displacement speed. Hence, kinematic diversity results in substantial differences in suction performance, beyond those expected based on the capacity to generate a high flow velocity. This functional complexity,in the form of biomechanically independent mechanisms that are recruited for one function, can potentially mitigate performance trade-offs in suction-feeding fishes.
Tips for teaching evidence-based medicine in a clinical setting: lessons from adult learning theory. Part one
Authors: Das Kausik , Malick Sadia , Khan Khalid S
Published: October 2008

Summary

Evidence-based medicine (EBM) is an indispensable tool in clinical practice. Teaching and training of EBM to trainee clinicians is patchy and fragmented at its best. Clinically integrated teaching of EBM is more likely to bring about changes in skills, attitudes and behaviour. Provision of evidence-based health care is the most ethical way to practice, as it integrates up-to-date, patient-oriented research into the clinical decision making process, thus improving patients' outcomes. In this article, we aim to dispel the myth that EBM is an academic and statistical exercise removed from practice by providing practical tips for teaching the minimum skills required to ask questions and critically identify and appraise the evidence and presenting an approach to teaching EBM within the existing clinical and educational training infrastructure.
The effect of ketamine/xylazine and carbon dioxide on plasma luteinizing hormone releasing hormone and testosterone concentrations in the male Norway rat
Authors: Gould E M
Published: October 2008

The effect of a commonly used anaesthetic, ketamine/xylazine and/or carbon dioxide (CO2) on plasma luteinizing hormone releasing hormone (LHRH) and testosterone concentrations was determined in male Sprague-Dawley rats. These values were compared with values obtained from pre-anaesthetic control samples. Ketamine/xylazine treatment did not significantly affect testosterone concentrations. In contrast, LHRH started to decrease one hour after ketamine/xylazine administration and continued to significantly decrease after 24 h. In addition, in the CO2euthanasia-only group, LHRH concentrations were also significantly decreased. These results suggest that ketamine/xylazine anaesthesia followed by CO2euthanasia 24 h later is exerting a significant effect on LHRH concentrations 24 h after anaesthetizing, while only having a slight effect on testosterone, and that CO2is exerting an immediate significant effect on LHRH. In conclusion, LHRH analysis should be avoided after ketamine/xylazine anaesthesia and CO2euthanasia.
Animal models of chronic lung infection withPseudomonas aeruginosa: useful tools for cystic fibrosis studies
Authors: Kukavica-Ibrulj I , Levesque R C
Published: October 2008

Cystic fibrosis (CF) is caused by a defect in the transmembrane conductance regulator (CFTR) protein that functions as a chloride channel. Dysfunction of the CFTR protein results in salty sweat, pancreatic insufficiency, intestinal obstruction, male infertility and severe pulmonary disease. In most patients with CF life expectancy is limited due to a progressive loss of functional lung tissue. Early in life a persistent neutrophylic inflammation can be demonstrated in the airways. The cause of this inflammation, the role of CFTR and the cause of lung morbidity by different CF-specific bacteria, mostly Pseudomonas aeruginosa, are not well understood. The lack of an appropriate animal model with multi-organ pathology having the characteristics of the human form of CF has hampered our understanding of the pathobiology and chronic lung infections of the disease for many years. This review summarizes the main characteristics of CF and focuses on several available animal models that have been frequently used in CF research. A better understanding of the chronic lung infection caused particularly by P. aeruginosa, the pathophysiology of lung inflammation and the pathogenesis of lung disease necessitates animal models to understand CF, and to develop and improve treatment.
Repeated anaesthesia with isoflurane and xylazine/levomethadone/fenpipramide premedication in female Beagle dogs: Influence on general health and wellbeing
Authors: Bert B , Hartje I , Voigt J-P , Arndt G , Ulbrich H-F , Fink H , Hauff P
Published: October 2008

Beagle dogs continue to be used in experimental studies and preclinical and clinical trials, many of which address the usage of anaesthesia. In order to reduce the number of animals, researchers tend to conduct several experiments on a single animal. The question arises, however, as to whether or not this frequent usage involves more than simply additional stress and discomfort for the individual animal. Within the framework of an existing study involving six female Beagle dogs, we investigated the effects of repeated (5) isoflurane anaesthesia with xylazine/levomethadone/fenpipramide premedication carried out at short intervals (2 weeks) and compared these with the effects of two treatments intermitted by a longer resting period (8 weeks). To verify our hypothesis that frequent anaesthesia affects the dog's wellbeing more than the occasional anaesthesia, the following parameters were measured at regular intervals: body weight, body temperature, respiratory rate, blood pressure, reflexes and heart rate, both at rest and during a treadmill exercise. In addition, recovery behaviour subsequent to anaesthesia was monitored for one hour. Our observations indicate that the anaesthetic effects are most prominent 24 h after the anaesthetic treatment. However, crossover analysis of our data cannot show that there is no statistical difference of whether dogs were anaesthetized occasionally or frequently. In our study, it appears that frequent anaesthesia within a two-week period did not affect the wellbeing and general health of Beagle dogs in a super-additive manner and that a minimum of two-week testing-free period is sufficient to ensure complete recovery from the unwanted effects induced by anaesthesia.
Slippage in Rebate Programs and Present-Biased Preferences
Authors: Gilpatric Scott M.
Published: October 2008

Present-biased preferences capture the idea that individuals may find immediate payoffs significantly more salient than any future payoffs, rather than simply discounting the future in a time-consistent manner. In this paper we show that consumers' present-biased preferences can generate slippage, and we explore whether this can explain firms' use of mail-in rebates. We assume that the consumer population comprises members who have various degrees of present bias. The model demonstrates that if consumers have homogeneous willingness to pay for a product (and thus rebates do not serve as a mechanism for traditional price discrimination) rebates may still profitably exploit slippage, but to do so they must generate very high slippage rates. This is, because the rebate must greatly exceed the price markup because the rebate must compensate consumers for the cost of redemption and the delay in receiving the rebate. The ability of rebate programs to take advantage of present-biased consumers is quite limited in settings where there is significant variance in the degree of present bias within the population unless the extent of consumers' present bias is highly correlated with their rebate redemption costs.
The Value of Partial Resource Pooling: Should a Service Network Be Integrated or Product-Focused?
Authors: Ata Barış , Van Mieghem Jan A.
Published: October 2008

We investigate how dynamic resource substitution in service systems impacts capacity requirements and responsiveness. Inspired by the contrasting network strategies of FedEx and United Parcel Service (UPS), we study when two service classes (e.g., express or regular) should be served by dedicated resources (e.g., air or ground) or by an integrated network (e.g., air also serves regular). Using call center terminology, the question is whether to operate two independent queues or one N-network. We present analytic expressions for the delay distributions and the value of network integration through partial resource pooling. These show how the value of network integration depends on service quality (speed and reliability of service) and demand characteristics (volume averages and covariance matrix). Our results suggest that network integration is of little value and operating dedicated networks is a fine strategy if the firm primarily serves express requests with high reliability and if the correlation with regular requests is not strongly negative. In contrast, network integration offers significant gains for firms serving primarily regular requests, almost independent of correlation. Our analysis provides the intuition behind these findings in terms of three main drivers of integration value: arrival pooling, the substitution effect, and the correlation effect.
Satisficing Measures for Analysis of Risky Positions
Authors: Brown David B. , Sim Melvyn
Published: October 2008

In this work we introduce a class of measures for evaluating the quality of financial positions based on their ability to achieve desired financial goals. In the spirit of Simon (Simon, H. A. 1959. Theories of decision-making in economics and behavioral science. Amer. Econom. Rev. 49(3) 253–283), we call these measures satisficing measures and show that they are dual to classes of risk measures. This approach has the advantage that aspiration levels, either competing benchmarks or fixed targets, are often much more natural to specify than risk tolerance parameters. In addition, we propose a class of satisficing measures that reward diversification. Finding optimal portfolios for such satisficing measures is computationally tractable. Moreover, this class of satisficing measures has an ambiguity interpretation in terms of robust guarantees on the expected performance because the underlying distribution deviates from the investor's reference distribution. Finally, we show some promising results for our approach compared to traditional methods in a real-world portfolio problem against a competing benchmark.
The Power of Stars: Do Star Actors Drive the Success of Movies?
Authors: Elberse Anita
Published: October 2008

Is the involvement of stars critical to the success of motion pictures? Film studios, which regularly pay multimillion-dollar fees to stars, seem to be driven by that belief. This article sheds light on the returns on this investment using an event study that considers the impact of more than 1200 casting announcements on trading behavior in a simulated and real stock market setting. The author finds evidence that the involvement of stars affects movies' expected theatrical revenues and provides insight into the magnitude of this effect. For example, the estimates suggest that, on average, stars are worth approximately $3 million in theatrical revenues. In a cross-sectional analysis grounded in the literature on group dynamics, the author also examines the determinants of the magnitude of stars' impact on expected revenues. Among other things, the author shows that the stronger a cast already is, the greater is the impact of a newly recruited star with a track record of box office successes or with a strong artistic reputation. Finally, in an extension to the study, the author does not find that the involvement of stars in movies increases the valuation of film companies that release the movies, thus providing insufficient grounds to conclude that stars add more value than they capture. The author discusses implications for managers in the motion picture industry.
Friendship versus Business in Marketing Relationships
Authors: Grayson Kent
Published: October 2008

Although combining friendship and business in the same relationship can be beneficial, it can also create conflict. A source of this conflict is incompatible relational expectations. True friends are expected to be unmotivated by benefits that can be used beyond the relationship (e.g., money, status), whereas business partners are, by definition, at least partly motivated by these more “instrumental” concerns. Using a role theory framework and data collected from a survey of 685 direct-selling agents, this article reports evidence that a conflict between friendship and instrumentality can undermine some of the business outcomes that friendship might otherwise foster. It also suggests that this conflict is more severe for friendships that become business relationships than for business relationships that become friendships. Study conclusions do not suggest that friendship is entirely “bad” for business and, instead, propose that friendship's influence can be both positive and negative.
Optimal Design of Consumer Contests
Authors: Liu De , Geng Xianjun , Whinston Andrew B.
Published: October 2008

A consumer contest is a sales promotion technique that requires participants to apply certain skills as they compete for prizes or awards. This article is the first to employ a game-theoretical approach to investigate consumer contest design issues, including prize structure, segmentation, and handicapping. First, the authors find that both skill distribution and the number of contestants play an important role in determining the optimal prize structure in consumer contests. Specifically, if the skill distribution has the increasing hazard-rate property, it is optimal for a marketer to use a winner-take-all design. In large contests, for the winner-take-all approach to be optimal, it suffices to have the increasing hazard-rate property only at the high end of the skill distribution. Second, increasing contest size is beneficial to the marketer. Third, a less dispersive skill distribution leads to higher consumption by consumers at all skill levels and thus is beneficial to the marketer. The marketer may achieve less dispersive skill distributions by (1) segmenting or screening contestants according to their skill levels and (2) adopting a performance evaluation scheme that handicaps high-skilled contestants.
Strategic Change Implementation and Performance Loss in the Front Lines
Authors: Ye Jun , Marinova Detelina , Singh Jagdip
Published: October 2008

Adopting a frontline employee (FLE) perspective, this study models a performance loss process during an organization's strategic change implementation. The process is activated by changes in unit management's emphases on cost containment and revenue-generating strategies and is governed by FLE detachment. The authors also examine an intervention mechanism for mitigating performance loss by including the influence of FLE participation in change decisions. The model is tested with data from five service organizations that employ 843 FLEs. The results indicate that (1) FLE detachment is effective in separating out the negative and positive effects of change, (2) FLE change perceptions are sensitive to the focus of strategic change (cost containment versus revenue enhancement strategies), and (3) FLE participation significantly enhances the positive effects of change and mitigates performance loss.
Customer Equity: An Integral Part of Financial Reporting
Authors: Wiesel Thorsten , Skiera Bernd , Villanueva Julián
Published: October 2008

Recent initiatives demand information that supplements and complements a firm's financial statements to bridge the gap between financial statement capabilities and financial reporting objectives. Such information assists investors' decision making by explaining the main trends and factors that underlie the development, performance, and position of the firm's business. Firms that aim to increase the value of their customer base should report forward-looking customer metrics because such reports align customer management with corporate goals and investors' perspectives. The authors propose a means to report customer equity that enables investors—the “consumers” of financial reports—to monitor firms' performance with respect to their customer assets. Furthermore, they develop a specific model for Netflix and apply it to quarterly data from September 2001 to September 2006.
Configurations of Marketing and Sales: A Taxonomy
Authors: Homburg Christian , Jensen Ove , Krohmer Harley
Published: October 2008

Little is known about the interface between separate marketing units and sales units. This article develops a multidimensional model of the marketing and sales interface. The model integrates a broad range of conceptual domains, including information sharing, structural linkages, power, orientations, and knowledge of marketing and sales. The authors empirically explore the conceptual model through a cross-industry study of 337 European Union–based companies. They identify five empirical archetypes of the marketing and sales interface. The taxonomy shows that the role and characteristics of marketing and sales vary a great deal. This finding challenges existing stereotypes about marketing and sales. Finally, the article explores organizational outcomes of the five configurations. The findings suggest that the most successful configurations are characterized by strong structural linkages between marketing and sales and a high extent of market knowledge in marketing.
Demand-Based Pricing versus Past-Price Dependence: A Cost–Benefit Analysis
Authors: Srinivasan Shuba , Pauwels Koen , Nijs Vincent
Published: October 2008

The authors develop a conceptual framework of the factors that motivate a retailer's decision to rely on demand conditions and past prices in setting current and future prices. Specifically, they examine the circumstances under which retailers choose demand-based pricing versus past-price dependence for different brands and categories. Given scarce resources and costs of price adjustments, demand-based pricing is more likely when the customer-driven and firm-driven costs of adjusting pricing patterns are low or when the benefits of such adjustments are high. First, the customer-driven benefits of demand-based pricing are expected to be greater in categories with higher penetration and for brands with higher market share and higher demand sensitivity to price. Second, the firm-driven benefits are greater for categories with higher private-label share. Finally, the customer-driven costs are greater for expensive categories, whereas the firm-driven costs are greater for categories with many stockkeeping units. The empirical findings support the conceptual framework, implying that customer-driven and firm-driven benefits are the main stimulants in the retailer's choice of demand-based pricing. In contrast, customer-driven and firm-driven costs significantly hinder retailer implementation of demand-based pricing. These insights enable retailers to identify problem areas and opportunities to improve the allocation of scarce pricing resources. The results also contribute to the ongoing debate in economics and marketing on the rationality of observed past-price dependence. Whereas previous research points to the negative impact on gross margins of this practice, the authors find that retailers weigh the costs and benefits of demand-based pricing rather than adhere to past-pricing patterns.
Do Frontline Mechanisms Matter? Impact of Quality and Productivity Orientations on Unit Revenue, Efficiency, and Customer Satisfaction
Authors: Marinova Detelina , Ye Jun , Singh Jagdip
Published: October 2008

This study identifies a frontline mechanism comprising autonomy, cohesion, and feedback that helps explain when and why the simultaneous pursuit of quality and productivity orientations has positive or negative effects on unit revenue, efficiency, and customer satisfaction. An empirical test of the proposed framework using data from 423 employees in 30 strategic business units and longitudinal unit-level performance data indicates that frontline autonomy mediates the positive impact of productivity and quality orientations on unit revenue and customer satisfaction and their negative impact on unit efficiency. Feedback amplifies the influence of frontline autonomy by simultaneously enhancing its positive effect on satisfaction and its negative effect on efficiency. In contrast, unit cohesion strengthens the positive effect of frontline autonomy on revenue and customer satisfaction without augmenting its negative effect on unit efficiency. The results urge managers to shift their focus toward unit-level mechanisms to find clues for managing strategic dilemmas that stem from multiple goal pursuit in face-to-face service settings.
Convergent Products: What Functionalities Add More Value to the Base?
Authors: Gill Tripat
Published: October 2008

Convergence in the electronics sector has enabled the addition of disparate new functionalities to existing base products (e.g., adding mobile television to a cell phone or Internet access to a personal digital assistant). This research investigates the role of two factors—(1) the goal congruence between the added functionality and the base and (2) the nature of the base product (utilitarian versus hedonic)—on the evaluation of such convergent products (CPs). The author proposes that the evaluation of CPs with a utilitarian versus hedonic base is subject to an asymmetric additivity effect. Specifically, whereas CPs with a utilitarian base gain more from adding an incongruent, hedonic functionality than a congruent, utilitarian one, CPs with a hedonic base gain less from an incongruent, utilitarian addition than a congruent, hedonic one. This asymmetry is because hedonic additions enhance the pleasure of using a utilitarian base, whereas utilitarian additions may dilute the existing hedonic image of a hedonic base. The moderating role of prior ownership of the base of a CP is also explored. The author proposes that the effects of goal congruence are stronger for owners than for nonowners, but only for CPs with a hedonic base, not for those with a utilitarian base. The author verifies the proposed effects in an experimental study conducted with a large-scale, representative sample of the target market population. Further research on other (moderating) factors affecting the evaluation of CPs is also suggested.