bluuebunny/crossref_metadata_2025_split huggingface dataset:
RECURSIVE GENERALIZED M ESTIMATES FOR AUTOREGRESSIVE MOVING‐AVERAGE MODELS
Authors: Allende Hector , Heiler Siegfried 
Published: May 2008

Abstract.Outliers in time series seriously affect conventional parameter estimates. In this paper a robust recursive estimation procedure for the parameters of auto‐regressve moving‐average models with additive outliers is proposed. Using ‘cleaned’ residuals from an initial robust fit of an autoregression of high order as input, bounded influence regression is applied recursively. The proposal follows certain ideas of Hannan and Rissanen, who suggested a three‐stage procedure for order and parameter estimation in a conventional setting.A Monte Carlo study is performed to investigate the robustness properties of the proposed class of estimates and to compare them with various other suggestions, including least squares, M estimates, residual autocovariance and truncated residual autocovariance estimates. The results show that the recursive generalized M estimates compare favourably with them. Finally, possible modifications to master even vigourous situations are suggested.
Labour Demand, Flexible Contracts and Financial Factors: Firm‐Level Evidence from Spain*
Authors: Benito Andrew , Hernando Ignacio 
Published: May 2008

AbstractWe estimate models of labour demand for a panel of 3,400 Spanish manufacturing firms over the period 1985–2001. We examine the roles of fixed‐term contracts, financial factors and a policy reform in 1997 affecting permanent contracts by lowering payroll taxes and dismissal costs. Compared with permanent employment, the demand for flexible labour displays: (i) greater sensitivity to financial factors; (ii) greater cyclical sensitivity; (iii) a larger average wage elasticity; and (iv) less inertia. Our analysis of the 1997 policy reform suggests that a 5 percentage point reduction in the payroll tax is associated with an 8% increase in permanent labour demand.
Lipoprotein(a) in patients initiating antiretroviral therapy
Authors: Mauss S , Berger F , Schmutz G , Henke J , Richter WO 
Published: May 2008

ObjectivesThe interaction between lipoprotein(a), an emerging cardiovascular risk factor, and antiretrovirals (ARVs) has been less well studied than the interaction between either cholesterol or triglycerides and these drugs. In this study we assessed the effect of initiating antiretroviral therapy (ART) on lipoprotein(a) levels.MethodsFasting samples from 95 patients initiating ART with nucleoside/nucleotide reverse transcriptase inhibitors plus nonnucleoside reverse transcriptase inhibitors or protease inhibitors were obtained. Lipids and lipoproteins were determined until week 48.ResultsAs in the general population, the study population showed a highly skewed lipoprotein(a) distribution (median 9.9 mg/dL, range 0.1–110 mg/dL). The study population was divided into individuals with lipoprotein(a) ≥30 mg/dL at baseline (n=28) and those with <30 mg/dL (n=67). Almost exclusively, patients with high lipoprotein(a) at baseline (median 51.6 mg/dL) showed a profound increase of median 26.7 mg/dL (week 24). This effect was not associated with specific ARVs and was independent of changes in other lipids. The low‐lipoprotein(a) group (baseline median 7 mg/dL) showed a small increase of median 2.6 mg/dL (week 24).ConclusionsMarked increases in lipoprotein(a) after initiation of ART were mainly restricted to patients with high baseline levels. This may have clinical implications as patients with high lipoprotein(a) are at higher risk for myocardial infarction and stroke.
Adrenal suppression and Cushing's syndrome secondary to an interaction between ritonavir and fluticasone: a review of the literature
Authors: Foisy MM , Yakiwchuk EMK , Chiu I , Singh AE 
Published: May 2008

ObjectiveThe purpose of this article is to provide a systematic overview of the literature on adrenal suppression and Cushing's syndrome secondary to an interaction between inhaled/intranasal fluticasone and ritonavir. The clinical presentation, diagnosis and management will be discussed.MethodsA literature search using Medline and EMBASE and a search of abstracts of the three previous years of major HIV‐related conferences were carried out.ResultsThere were 25 cases (15 adult and 10 paediatric) of significant adrenal suppression secondary to an interaction between ritonavir and inhaled fluticasone, and three cases involving ritonavir and intranasal fluticasone. Cases with other steroids were not reported; however, there were cases of adrenal suppression with itraconazole [also a potent cytochrome p (CYP) 3A4 inhibitor] and inhaled budesonide. Clinicians need to differentiate between antiretroviral‐induced lipodystrophy syndrome and iatrogenic Cushing's syndrome secondary to glucocorticoid use. Long‐term fluticasone and ritonavir should be avoided. If ritonavir is required, another inhaled steroid such as low‐dose budesonide or beclomethasone can be used cautiously. Upon discontinuation of inhaled corticosteroids, close monitoring for symptoms of adrenal insufficiency is warranted. The need for steroid replacement therapy at physiological doses should be assessed.ConclusionsThe combination of ritonavir and fluticasone should be avoided. Budesonide, beclomethasone, triamcinolone and flunisolide appear to be safer options.
Explaining Attitudes towards Self‐employment among Immigrants: A Canadian Case Study
Authors: Bauder Harald 
Published: May 2008

ABSTRACTImplicit in Canada's immigration policies is that some immigrants are endowed with a particular entrepreneurial spirit, and that this spirit relates to immigrants’ origin. This paper examines whether attitudes towards entrepreneurship indeed relate to origin, or whether they can be explained through labour market circumstances at the place of settlement and/or Canada's immigrant selection procedure. The empirical study focuses on the reported attitudes towards entrepreneurship. A survey of 509 Vancouver residents of a predominantly Chinese immigrant neighbourhood, a predominantly South Asian immigrant neighbourhood, and a neighbourhood of non‐immigrants reveals that ethnic origin is a weak indicator of entrepreneurial attitudes. Instead, urban or rural background emerges as a more powerful predictor. The results also raise doubts about whether the Canadian government's immigration policy, which selects immigrants on the basis of economic potential, indeed selects immigrants with a greater desire to become self‐employed. Furthermore, the amount of time immigrants have spent in Canada does not significantly affect attitudes towards entrepreneurship.
Consumption of foods and foodstuffs processed with hazardous chemicals: a case study of Bangladesh
Authors: Hossain Md. Motaher , Heinonen Visa , Islam K. M. Zahidul 
Published: May 2008

AbstractDetermining the best way to persuade consumers to consume more healthy foods is challenging. In Bangladesh, however, daily newspapers consistently show that various hazardous chemicals (e.g. calcium carbide, sodium cyclamate, cyanide and formalin, etc.) are mixed with or added to foods and foodstuffs. These chemicals are very dangerous to humans. This present study examines the reasons behind the use of hazardous chemicals in foods as well as the extent to which food producers/sellers use such chemicals. In addition, this study assesses consumer perceptions of and attitudes towards these contaminated food items and explores how adulterated foods and foodstuffs affect consumer health. The empirical data were collected from 110 consumers, 25 sellers or producers, seven doctors and seven pharmacists in Dhaka, the capital of Bangladesh. This study shows that nearly every consumer (93.7%) is aware that various foods and foodstuffs contain hazardous chemicals, and that 95.5% of consumers are aware that these adulterated foods and foodstuffs are harmful to their health. This paper explores the myriad reasons why consumers nevertheless feel compelled to consume such chemically treated foods.
Effects of retinoic acids on the dendritic morphology of cultured hippocampal neurons
Authors: Liu Ying , Kagechika Hiroyuki , Ishikawa Junko , Hirano Hitoshi , Matsukuma Satoshi , Tanaka Kazuko , Nakamura Shoji 
Published: May 2008

AbstractVitamin A‐derived retinoic acids (RAs) are known to exert a variety of biological actions, including modulatory effects on cell differentiation and apoptosis. A recent study has demonstrated that 13‐cis‐RA and all‐trans‐RA suppressed neurogenesis in the dentate gyrus of the hippocampus in adult mice. The present experiments were performed to see whether 13‐cis‐RA and all‐trans‐RA could alter the dendritic morphology of cultured hippocampal neurons via RA receptors: retinoic acid receptor (RAR) and retinoid X receptor (RXR). High doses of 13‐cis‐RA and all‐trans‐RA exerted a negative effect on the cultured hippocampal neurons, while a low dose of 13‐cis‐RA but not all‐trans‐RA caused a positive effect. The negative changes induced by 13‐cis‐RA and all‐trans‐RA were antagonized by RXR antagonists and RAR antagonists, respectively. The positive changes induced by a low dose of 13‐cis‐RA were blocked by both RXR antagonists and RAR antagonists. These results suggest that RAs at high concentrations cause a negative effect on the dendritic morphology of cultured hippocampal neurons through RA receptors, while RAs at low concentrations exert a positive influence on cultured hippocampal neurons.
Neuroadaptive changes in the mesocortical glutamatergic system during chronic nicotine self‐administration and after extinction in rats
Authors: Wang Fan , Chen Hao , Sharp Burt M. 
Published: May 2008

AbstractNicotine self‐administration causes adaptation in the mesocorticolimbic glutamatergic system, including the up‐regulation of ionotropic glutamate receptor subunits. We therefore determined the effects of nicotine self‐administration and extinction on NMDA‐induced glutamate neurotransmission between the medial prefrontal cortex (mPFC) and ventral tegmental area (VTA). On day 19 of nicotine SA, both regions were microdialyzed for glutamate while mPFC was sequentially perfused with Kreb’s Ringer buffer (KRB), 200 μM NMDA, KRB, 500 μM NMDA, KRB, and 100 mM KCl. Basal glutamate levels were unaffected, but nicotine self‐administration significantly potentiated mPFC glutamate release to 200 μM NMDA, which was ineffective in controls. Furthermore, in VTA, nicotine self‐administration significantly amplified glutamate responses to both mPFC infusions of NMDA. This hyper‐responsive glutamate neurotransmission and enhanced glutamate subunit expression were reversed by extinction. Behavioral studies also showed that a microinjection of 2‐amino‐5‐phosphonopentanoic acid (NMDA‐R antagonist) into mPFC did not affect nicotine or sucrose self‐administration. However, in VTA, NBQX (AMPA‐R antagonist) attenuated both nicotine and sucrose self‐administration. Collectively, these studies indicate that mesocortical glutamate neurotransmission adapts to chronic nicotine self‐administration and VTA AMPA‐R may be involved in the maintenance of nicotine self‐administration.
Leptin neuroprotection in the CNS: mechanisms and therapeutic potentials
Authors: Signore Armando P. , Zhang Feng , Weng Zhongfang , Gao YanQin , Chen Jun 
Published: May 2008

AbstractLeptin is well known as a hormone important in the central control of appetitive behaviors via receptor‐mediated actions in the hypothalamus, where leptin adjusts food intake to maintain homeostasis with the body’s energy stores. Recent evidence has shown that leptin and its receptors are widespread in the CNS and may provide neuronal survival signals. This review summarizes our current knowledge of how leptin functions in the brain and then focuses on the ability of leptin to mitigate neuronal damage in experimental models of human neurological disorders. Damage to the brain by acute events such as stroke, or long‐term loss of neurons associated with neurodegenerative diseases, including Parkinson’s and Alzheimer’s disease, may be amenable to treatment using leptin to limit death of susceptible cells. Leptin‐mediated pro‐survival signaling is now known to prevent the death of neurons in these models. The signaling cascades that leptin generates are shared by other neuroprotective molecules including insulin and erythropoietin, and are thus a component of the neurotrophic effects mediated by endogenous hormones. Coupled with evidence that leptin dysregulation in human disease also results in enhanced neuronal susceptibility to damage, development of leptin as a therapeutic methodology is an attractive and viable possibility.
Lovastatin effect in rat neuroblasts of the CNS: inhibition of cap‐dependent translation
Authors: Santa‐Catalina Marta Olivera , Garcia‐Marin Luis Jesus , Bragado María Julia 
Published: May 2008

AbstractMevalonate biosynthesis pathway is important in cell growth and survival and its blockade by 3‐hydroxy‐3‐methylglutaryl CoA reductase inhibitors, statins, arrest brain neuroblasts growth and induce apoptosis. Translation is among the main biochemical mechanisms that controls gene expression and therefore cell growth or apoptosis. In the CNS, translation regulates synaptic plasticity. Thus, our aim was to investigate the effect of lovastatin in protein translation in rat neuroblasts of the CNS and the biochemical pathways involved. Lovastatin treatment in rat brain neuroblasts causes a significant time‐ and concentration‐inhibition of protein synthesis, which is partially mediated by phosphatydilinositol 3‐kinase/mammalian target of rapamycin (mTOR) pathway inhibition. Lovastatin treatment decreases the phosphorylation state of mTOR substrates, p70S6K and eukaryotic translation initiation factor (eIF) 4E‐binding protein 1 and simultaneously increases eIF4E‐binding protein 1 in a time‐dependent manner. Concomitantly, lovastatin causes a decrease in eIF4G cellular amount, which is partially mediated by caspase(s) activity excluding caspase 3. These biochemical pathways affected by lovastatin might explain the protein translation inhibition observed in neuroblasts. Cycloheximide treatment, which blocked protein synthesis, does not induce neuroblasts apoptosis. Therefore, we suggest that lovastatin‐induced protein synthesis inhibition might not contribute to the concomitant neuroblasts apoptosis previously observed.
The ketogenic diet increases mitochondrial glutathione levels
Authors: Jarrett Stuart G. , Milder Julie B. , Liang Li‐Ping , Patel Manisha 
Published: May 2008

AbstractThe ketogenic diet (KD) is a high‐fat, low carbohydrate diet that is used as a therapy for intractable epilepsy. However, the mechanism(s) by which the KD achieves neuroprotection and/or seizure control are not yet known. We sought to determine whether the KD improves mitochondrial redox status. Adolescent Sprague–Dawley rats (P28) were fed a KD or control diet for 3 weeks and ketosis was confirmed by plasma levels of β‐hydroxybutyrate (BHB). KD‐fed rats showed a twofold increase in hippocampal mitochondrial GSH and GSH/GSSG ratios compared with control diet‐fed rats. To determine whether elevated mitochondrial GSH was associated with increased de novo synthesis, the enzymatic activity of glutamate cysteine ligase (GCL) (the rate‐limiting enzyme in GSH biosynthesis) and protein levels of the catalytic (GCLC) and modulatory (GCLM) subunits of GCL were analyzed. Increased GCL activity was observed in KD‐fed rats, as well as up‐regulated protein levels of GCL subunits. Reduced CoA (CoASH), an indicator of mitochondrial redox status, and lipoic acid, a thiol antioxidant, were also significantly increased in the hippocampus of KD‐fed rats compared with controls. As GSH is a major mitochondrial antioxidant that protects mitochondrial DNA (mtDNA) against oxidative damage, we measured mitochondrial H2O2 production and H2O2‐induced mtDNA damage. Isolated hippocampal mitochondria from KD‐fed rats showed functional consequences consistent with the improvement of mitochondrial redox status i.e. decreased H2O2 production and mtDNA damage. Together, the results demonstrate that the KD up‐regulates GSH biosynthesis, enhances mitochondrial antioxidant status, and protects mtDNA from oxidant‐induced damage.
Cerebellar granule cells cultured from adolescent rats express functional NMDA receptors: anin vitromodel for studying the developing cerebellum
Authors: Popp R. Lisa , Reneau Jason C. , Dertien Janet S. 
Published: May 2008

AbstractIn the developing rat cerebellum functional NMDA receptors (NMDARs) expressing the NR2C subunit have been identified on or after postnatal day 19. We obtained primary cultured cells from 19‐ to 35‐day‐old rat cerebellum that expressed few oligodendrocytes or astrocytes. Cultured cells were immunoreactive for neuron‐specific proteins thus indicating a neuronal population. The primary neuron present was the granule cell as indicated by immunofluorescence for the GABAAalpha 6 subunit. Whole‐cell patch‐clamp experiments indicated that functional NMDARs were present. Functional characteristics of NMDARs expressed in cerebellar granule cells (CGCs) obtained from adolescent animals were similar to those previously reported for NMDARs expressed in CGCs obtained from neonatal rats. Cultured CGCs obtained from older animals contained NMDARs that were inhibited by EtOH and were less sensitive to the NR2B subunit‐specific antagonist Ro 25‐6981. Furthermore, NMDA‐induced currents were smaller than those observed in CGCs. Western blot analysis indicated the presence of the NMDA NR2A and NR2C subunits, but not the NR2B in cultures obtained from the adolescent rats. CGCs obtained from adolescent rats express functional NMDARs consistent with a developmental profile observedin vivo.
Does Doctor–Patient Communication Affect Patient Satisfaction with Hospital Care? Results of an Analysis with a Novel Instrumental Variable
Authors: Clever Sarah L. , Jin Lei , Levinson Wendy , Meltzer David O. 
Published: May 2008

Objective. To determine the relationship between physicians' communication behaviors and patients' overall satisfaction with hospital care using a novel instrumental variable to address possible confounding of this association by patient attributes.Data Sources/Study Setting. Administrative records and postdischarge survey data were obtained from patients discharged from the General Medicine service at an urban tertiary‐care academic hospital between July 1, 1997 and June 30, 2000. Administrative data included comorbidities, demographic data, and payer status. In the discharge survey, patients rated their attending physician on four communication behaviors, other aspects of their hospital stay, and their overall hospital care.Study Design. The primary outcome was patients' ratings of their overall satisfaction with hospital care, and the primary independent variable was patients' ratings of their physicians' communication behaviors. To remove possible confounding of the association between patient ratings of physician communication and overall satisfaction by other patient‐specific attributes, we created an instrumental variable (IV) in a two‐stage linear regression. The IV was the mean of the communication ratings given to each physician by the other patients cared for by that physician.Principle Findings/Conclusions. Three thousand one hundred and twenty‐three patients were included in the analysis. In the ordinary least squares regression, there was a significant positive relationship between overall satisfaction and overall ratings of attendings' communication behaviors, with an increase in overall satisfaction of 0.58 points on a 5‐point scale for each 1‐point increase in overall attendings' communication behaviors, p<.001. This relationship was maintained but attenuated in the IV regression, with a coefficient of 0.40, p=.046. Although we find that the relationship between patient communication ratings and overall patient satisfaction may be confounded by patient‐level factors, we nevertheless continue to find evidence of a statistically significant and sizable relationship between physicians' communication behaviors and overall patient satisfaction after controlling for such factors.
Pesticides, Preference Heterogeneity and Environmental Taxes
Authors: Chalak Ali , Balcombe Kelvin , Bailey Alastair , Fraser Iain 
Published: May 2008

AbstractIn this paper we present results from two choice experiments (CE), designed to take account of the different negative externalities associated with pesticide use in agricultural production. For cereal production, the most probable impact of pesticide use is a reduction in environmental quality. For fruit and vegetable production, the negative externality is on consumer health. Using latent class models we find evidence of the presence of preference heterogeneity in addition to reasonably high willingness to pay (WTP) estimates for a reduction in the use of pesticides for both environmental quality and consumer health. To place our WTP estimates in a policy context we convert them into an equivalent pesticide tax by type of externality. Our tax estimates suggest that pesticide taxes based on the primary externality resulting from a particular mode of agricultural production are a credible policy option that warrants further consideration.
The use of hyperbaric oxygen therapy to treat chronic wounds: A review
Authors: Thackham Jennifer A. , McElwain D.L. Sean , Long Robert J. 
Published: May 2008

ABSTRACTChronic wounds, defined as those wounds which fail to proceed through an orderly process to produce anatomic and functional integrity, are a significant socioeconomic problem. A wound may fail to heal for a variety of reasons including the use of corticosteroids, formation of squamous cell carcinoma, persistent infection, unrelieved pressure, and underlying hypoxia within the wound bed. Hypoxia appears to inhibit the wound healing process by blocking fibroblast proliferation, collagen production, and capillary angiogenesis and to increase the risk of infection. Hyperbaric oxygen therapy (HBOT) has been shown to aid the healing of ulcerated wounds and demonstrated to reduce the risk of amputation in diabetic patients. However, the causal reasons for the response of the underlying biological processes of wound repair to HBOT, such as the up‐regulation of angiogenesis and collagen synthesis are unclear and, consequently, current protocols remain empirical. Here we review chronic wound healing and the use of hyperbaric oxygen as an adjunctive treatment for nonhealing wounds. Databases including PubMed, ScienceDirect, Blackwell Synergy, and The Cochrane Library were searched for relevant phrases including HBOT, HBO/HBOT, wound healing, and chronic/nonhealing wounds/ulcers.
Delay of tympanic membrane wound healing in rats with topical application of a tyrosine kinase inhibitor
Authors: Kaftan Holger , Reuther Lars , Miehe Bärbel , Hosemann Werner , Herzog Michael 
Published: May 2008

ABSTRACTAn animal model of chronic tympanic membrane (TM) perforation is needed for experiments on supporting wound healing of TM perforations. The epidermal growth factor receptor (EGFR) has been implicated in the regulation of wound healing. The object of this study was to investigate the efficacy of topical EGFR‐inhibitor (erlotinib) to arrest wound healing of experimental TM perforation in rats. Bilateral instrumental myringotomies were performed in 13 male rats. A solution of erlotinib (10 mg/mL) was applied to one TM of each animal and vehicle only (control group) to the other side. The application procedure was repeated on both sides daily for 12 consecutive days. Thereafter, tympanic membranes were observed weekly for a total of 30 days. The mean healing period was found to be 12.1 days in the group with erlotinib and 6.4 days in the control group. The difference was significant. We observed differences in the histologic parameters between erlotinib group and control group. The inhibition of EGFR by topical application of erlotinib did delay the healing rate of myringotomies but seems not to be suitable to create a chronic TM perforation in rat.