bluuebunny/crossref_metadata_2025 huggingface dataset:
A consumer's guide to nestedness analysis
Authors: Ulrich Werner , Almeida‐Neto Mário , Gotelli Nicholas J.
Published: December 2008

Nestedness analysis has become increasingly popular in the study of biogeographic patterns of species occurrence. Nested patterns are those in which the species composition of small assemblages is a nested subset of larger assemblages. For species interaction networks such as plant–pollinator webs, nestedness analysis has also proven a valuable tool for revealing ecological and evolutionary constraints. Despite this popularity, there has been substantial controversy in the literature over the best methods to define and quantify nestedness, and how to test for patterns of nestedness against an appropriate statistical null hypothesis. Here we review this rapidly developing literature and provide suggestions and guidelines for proper analyses. We focus on the logic and the performance of different metrics and the proper choice of null models for statistical inference. We observe that traditional ‘gap‐counting’ metrics are biased towards species loss among columns (occupied sites) and that many metrics are not invariant to basic matrix properties. The study of nestedness should be combined with an appropriate gradient analysis to infer possible causes of the observed presence–absence sequence. In our view, statistical inference should be based on a null model in which row and columns sums are fixed. Under this model, only a relatively small number of published empirical matrices are significantly nested. We call for a critical reassessment of previous studies that have used biased metrics and unconstrained null models for statistical inference.
Limitations of entropy maximization in ecology: a reply to Haegeman and Loreau
Authors: Shipley Bill
Published: December 2008

Haegeman and Loreau published a paper that is primarily a criticism of a maximum entropy model of trait‐based community assembly (by Shipley et al.) and purports to show the limitations of this method in ecology. However, they misunderstood the basic purpose, logic and justification of the maximum entropy formalism and, because of this, leveled criticisms of Shipley et al. that are unfounded. Part of the confusion can be traced to sloppy presentation of the underlying approach in Shipley et al. The confusion arises because maximum entropy models are justified based on information theory and Bayesian logic while the interpretation that Haegeman and Loreau present is based on substantive empirical assumptions about microstate allocations and a combinatorial argument that do not apply to maximum entropy models and which I do not apply to my model in particular.
MAGNETIC RESONANCE IMAGING OF THE INITIAL ACTIVE STAGE OF EQUINE LAMINITIS AT 4.7 T
Authors: Arble Jason B. , Mattoon John S. , Drost Wm. Tod , Weisbrode Steven E. , Wassenaar Peter A. , Pan Xueliang , Hunt Robert J. , Belknap James K.
Published: December 2008

Equine laminitis is a severely debilitating disease. There is a poor understanding of the underlying pathophysiology, and traditional imaging modalities have limited diagnostic capacity. High field strength magnetic resonance (MR) imaging allows direct visualization of the laminae, which other modalities do not. This would prove useful both in assessment of clinical patients and in further investigation into the pathophysiology of the disease. The objective of this study was to characterize the anatomic changes within the equine foot associated with the initial active stage of laminitis. Images obtained using a 4.7 T magnet were compared with digital radiographs using histologic diagnosis as the reference standard. Objective measurements and subjective evaluation for both modalities were evaluated for the ability to predict the histologic diagnosis in horses with clinical signs of laminitis as well as in clinically normal horses and horses that were in a population at risk for developing laminitis. Signal intensity and architectural changes within the corium and laminae were readily seen at 4.7 T, and there was a strong association with the histologic diagnosis of active laminitis. Measurements obtained with MR imaging were more sensitive and specific predictors of laminitis than those obtained radiographically. Subjective evaluation with MR imaging was more sensitive than with radiography and should become more specific with greater understanding of normal anatomy.
OSSEOUS LESIONS IN THE METACARPO(TARSO)PHALANGEAL JOINT DIAGNOSED USING LOW‐FIELD MAGNETIC RESONANCE IMAGING IN STANDING HORSES
Authors: SHERLOCK CERI E. , MAIR TIMOTHY S. , TER BRAAKE FRERIK
Published: December 2008

We report the use of low‐field standing magnetic resonance imaging in the standing horse for the diagnosis of osseous lesions in the metacarpophalangeal (MCP) or metatarsophalangeal (MTP) joint that were not apparent using standard radiography. Thirteen horses were studied and all had thickening of the subchondral bone plate and abnormal signal intensity in the adjacent spongiosa in either the condyles of metacarpal/metatarsal III or the proximal phalanx or both. Abnormalities were characterized by diffuse decreased signal intensity on T1‐weighting adjacent to the subchondral bone and within the spongiosa in at least two imaging planes; in the absence of increases in signal intensity in fat‐suppressed images, this change was interpreted as bone sclerosis. Nine horses also had a diffuse decreased signal intensity on T2*‐weighting in the same areas and five had a diffuse increase in signal intensity in fat‐suppressed images in conjunction with a decrease in signal intensity on T1‐ and T2*‐weighted images; the increase in signal intensity in fat‐suppressed images was interpreted as fluid accumulation. Five horses had a focal area of change in signal intensity within the subchondral bone with apparent loss of definition between the subchondral bone and the articular cartilage. Eleven horses were available for follow up, of which eight were sound and three remained lame. We conclude that lameness originating from the MCP or MTP joint may be associated with osseous damage in horses of any signalment in the absence of radiographic changes.
MAGNETIC RESONANCE IMAGING FINDINGS OF DESMOPATHY OF THE COLLATERAL LIGAMENTS OF THE EQUINE DISTAL INTERPHALANGEAL JOINT
Authors: Gutierrez‐Nibeyro Santiago D. , White Nathaniel A. , Werpy Natasha M. , Tyrrell Laurie , Allen Kent A. , Sullins Kenneth E. , Mitchell Richard D.
Published: December 2008

We report the use of a low‐field magnetic resonance (MR) imaging system for the detection of desmopathy of the collateral ligament of the distal interphalangeal joint and the long‐term outcome. Twenty horses were studied and their medical records and MR images were reviewed retrospectively. Long‐term follow‐up information was obtained by telephonic questionnaires of owners, trainers, or referring veterinarians. Desmopathy of the medial collateral ligament (80%) and enthesopathy of the affected collateral ligament (80%) were common MR imaging features. Treatment consisted of stall rest followed by a rehabilitation period. Additional treatments included shoeing, extracorporeal shock wave therapy, application of a half limb or foot cast, and medication of the distal interphalangeal joint. Twelve (60%) horses returned to their previous level of exercise and maintained their previous level, whereas eight horses had a poor outcome. Low‐field MR imaging in the standing patient can be used to detect collateral ligament desmopathy of the distal interphalangeal joint without a need for general anesthesia.
QUANTITATIVE COMPUTED TOMOGRAPHY EVALUATION OF PULMONARY DISEASE
Authors: McEVOY FINTAN J. , BUELUND LENE , STRATHE ANDERS B. , WILLESEN JAKOB L. , KOCH JØRGEN , WEBSTER PIA , HØRLYCK LASSE , SVALASTOGA EILIV
Published: December 2008

Objective assessment of pulmonary disease from computed tomography (CT) examinations is desirable but difficult. When such assessments can be made, it is important that they are related to some part of the pathophysiologic process present. Herein we propose that automated volume histogram analysis can yield data that allow differentiation of normal from abnormal lung, and that the magnitude of disease will have an association with objective CT indices. Data from pulmonary CT images from 34 foxes (six uninfected controls and 28 infected with Angiostrongylus vasorum, subdivided by age and infective dose) were available. Lung tissue was segmented from surrounding tissue using an automated segmentation method. A volume histogram showing voxel frequency for each CT number in the range −1024 to −250 HU was created from the entire image stack from each fox. Using these data, the inter‐quartile range and the CT number at the 95th percentile were determined. The results showed that segmentation could be readily achieved but that areas of severely diseased lung were excluded. Based on two‐way analysis of variance for both the inter‐quartile range and the CT number at the 95th percentile, both quantities were significantly affected by the infection status of the animal and were related to worm burden (P<0.001). The study shows that this form of analysis is readily achieved and provides quantitative data that can be used to assess disease severity, progression, and response to treatment.
MULTIPHASE TIME‐RESOLVED CONTRAST‐ENHANCED PORTAL MRA IN NORMAL DOGS
Authors: MAI WILFRIED
Published: December 2008

Portal vein anomalies are common in dogs and cats. Diagnostic imaging is central in their diagnosis and fundamental with regard to choosing the best therapeutic option. Various imaging techniques are used in veterinary medicine to assess the portal vein. Each has individual advantages and disadvantages. Contrast‐enhanced magnetic resonance angiography (CE‐MRA) is used routinely in humans to image the portal system and has excellent spatial and temporal resolution and three‐dimensional (3D) acquisition. Herein, we report the development of a CE‐MRA protocol that resulted in fast 3D imaging of the arterial splanchnic and portal venous system in normal dogs. Multiphase acquisition strategy allowed acquiring the same volume several times during one single breath‐hold, thereby capturing the portal venous phase with excellent signal. Excellent depiction of the vascular anatomy, especially the portal afferent vessels and branches, was observed. Elliptical centric view ordering of k‐space was used to acquire the contrast‐sensitive data faster. Parallel imaging was used to increase coverage in the dorsal to ventral direction while keeping imaging time short. It is anticipated that 3D CE‐MRA is a fast and noninvasive imaging method that could be used to diagnose various portal vascular anomalies in small animals.
TIME‐RESOLVED RENAL CONTRAST‐ENHANCED MRA IN NORMAL DOGS
Authors: CAVRENNE ROMAIN , MAI WILFRIED
Published: December 2008

In humans, contrast‐enhanced magnetic resonance angiography (CE‐MRA) is a documented method to quantitatively and qualitatively evaluate renal vessels. It offers a safer alternative to computed tomography angiography. The aim of this study was to establish a renal MRA protocol in dogs using a 3D multiphase Fast Spoiled Gradient Recalled echo CE‐MRA sequence (3D FSPGR CE‐MRA). We used an elliptical centric ordering of k‐space to acquire the contrast‐sensitive data faster. Four to five consecutive 3D dorsal slabs, encompassing both kidneys, could be acquired in 40–65 s. The renal arterial and venous phases were obtained separately during phases 1 or 2, and 2 or 3, respectively without the need for any contrast medium bolus timing. The renal arteries and veins were clearly visualized. In conclusion, multiphase FSPGR 3D CE‐MRA with an elliptical centric k‐space ordering allows distinguishing renal arterial and venous phases in dogs, and can be used as a noninvasive diagnostic imaging alternative to map renal vessels in this species. Potential applications include the screening of renal donors in renal transplantation programs, and the pretreatment evaluation of animals with invasive renal neoplasia or renal vascular anomalies when surgery or embolization are contemplated.
IMAGING DIAGNOSIS—PULMONARY INTERSTITIAL EMPHYSEMA IN A DOG
Authors: BERTOLINI GIOVANNA , STEFANELLO CRISTIANO , CALDIN MARCO
Published: December 2008

In humans, pulmonary interstitial emphysema is most frequently seen in ventilated preterm newborns with severe lung disease; it is less frequently reported in adults. We report on a mature dog with pneumopathy that underwent computed tomography (CT) imaging to further characterize the lung disease. A bronchiolar pattern and lobar opacification were seen on the CT images. Moreover, gas was detected along the course of the pulmonary vessels, presumably in the interstitium, as seen in pulmonary interstitial emphysema in humans. Sever lung disease and/or hyperventilation during anesthesia could be a possible explanation of pulmonary interstitial emphysema in this dog.
SREBPs: protein interaction and SREBPs
Authors: Sato Ryuichiro
Published: December 2008

Sterol regulatory element‐binding proteins (SREBPs) are tightly controlled by various mechanisms, including intracellular localization, protein processing, limited proteolysis, post‐translational modifications and interaction with associated proteins. Here, I review the regulatory mechanisms of SREBP activity through the interaction with various kinds of protein.
SREBPs: SREBP function in glia–neuron interactions
Authors: Camargo Nutabi , Smit August B. , Verheijen Mark H. G.
Published: December 2008

The mammalian nervous system is relatively autonomous in lipid metabolism. In particular, Schwann cells in the peripheral nervous system, and oligodendrocytes and astrocytes in the central nervous system, are highly active in lipid synthesis. Previously, enzymatic lipid synthesis in the liver has been demonstrated to be under the control of the sterol regulatory element‐binding protein (SREBP) transcription factors. Here, we put forward the view that SREBP transcription factors in glia cells control the synthesis of lipids involved in various glia–neuron interactions, thereby affecting a range of neuronal functions. This minireview compiles current knowledge on the involvement of Schwann cell SREBPs in myelination of axons in the peripheral nervous system, and proposes a role for astrocyte SREBPs in neuronal functioning in the central nervous system.
Amino acid limitation regulates the expression of genes involved in several specific biological processes through GCN2‐dependent and GCN2‐independent pathways
Authors: Deval Christiane , Chaveroux Cédric , Maurin Anne‐Catherine , Cherasse Yoan , Parry Laurent , Carraro Valérie , Milenkovic Dragan , Ferrara Marc , Bruhat Alain , Jousse Céline , Fafournoux Pierre
Published: December 2008

Evidence has accumulated that amino acids play an important role in controlling gene expression. Nevertheless, two components of the amino acid control of gene expression are not yet completely understood in mammals: (a) the target genes and biological processes regulated by amino acid availability, and (b) the signaling pathways that mediate the amino acid response. Using large‐scale analysis of gene expression, the objective of this study was to gain a better understanding of the control of gene expression by amino acid limitation. We found that a 6 h period of leucine starvation regulated the expression of a specific set of genes: 420 genes were up‐regulated by more than 1.8‐fold and 311 genes were down‐regulated. These genes were involved in the control of several biological processes, such as amino acid metabolism, lipid metabolism and signal regulation. Using GCN2−/− cells and rapamycin treatment, we checked for the role of mGCN2 and mTORC1 kinases in this regulation. We found that (a) the GCN2 pathway was the major, but not unique, signaling pathway involved in the up‐ and down‐regulation of gene expression in response to amino acid starvation, and (b) that rapamycin regulates the expression of a set of genes that only partially overlaps with the set of genes regulated by leucine starvation.
Characterization of the rice carotenoid cleavage dioxygenase 1 reveals a novel route for geranial biosynthesis
Authors: Ilg Andrea , Beyer Peter , Al‐Babili Salim
Published: December 2008

Carotenoid cleavage products – apocarotenoids – include biologically active compounds, such as hormones, pigments and volatiles. Their biosynthesis is initiated by the oxidative cleavage of C–C double bonds in carotenoid backbones, leading to aldehydes and/or ketones. This step is catalyzed by carotenoid oxygenases, which constitute an ubiquitous enzyme family, including the group of plant carotenoid cleavage dioxygenases 1 (CCD1s), which mediates the formation of volatile C13 ketones, such as β‐ionone, by cleaving the C9–C10 and C9′–C10′ double bonds of cyclic and acyclic carotenoids. Recently, it was reported that plant CCD1s also act on the C5–C6/C5′–C6′ double bonds of acyclic carotenes, leading to the volatile C8 ketone 6‐methyl‐5‐hepten‐2‐one. Using in vitro and in vivo assays, we show here that rice CCD1 converts lycopene into the three different volatiles, pseudoionone, 6‐methyl‐5‐hepten‐2‐one, and geranial (C10), suggesting that the C7–C8/C7′–C8′ double bonds of acyclic carotenoid ends constitute a novel cleavage site for the CCD1 plant subfamily. The results were confirmed by HPLC, LC‐MS and GC‐MS analyses, and further substantiated by in vitro incubations with the monocyclic carotenoid 3‐OH‐γ‐carotene and with linear synthetic substrates. Bicyclic carotenoids were cleaved, as reported for other plant CCD1s, at the C9–C10 and C9′–C10′ double bonds. Our study reveals a novel source for the widely occurring plant volatile geranial, which is the cleavage of noncyclic ends of carotenoids.
THERMAL BEHAVIOR PREDICTION OF FOOD PARTICULATES UNDER AMBIENT AND CRYOGENIC CONDITIONS
Authors: SRIDHAR B.S. , MANOHAR B. , SOMMER K.
Published: December 2008

This article describes experiments to quantitatively characterize the thermal effects of solid food particulates in terms of temperature increment as a function of particle size under ambient and cryogenic conditions using turmeric (Curcuma longa L.) as a model material. The log‐normal function was used to characterize the thermal behavior. Cylindrical specimens of turmeric were impacted diametrally, and the resulting particle size distributions and cumulative volume fraction were measured by computerized inspection particle size analyzer. The various model parameters estimated under the said conditions, such as surface‐volume ratio, energy density and combined strength parameter, were found to be in the range of 3.5 × 103–1.14 × 106 (m−1), 2.4 × 105–6.6 × 107 J/m3 and 174.1–229.5 J/m2, respectively. The temperature change ΔT (C) was calculated in terms of log‐normal parameters and material properties such as the specific heat and local energy density. The calculated ΔT was plotted as a function of size of particles. Local temperature rise up to 114.5 and 67.2C was found for the particle size of 12 µm or lower for ambient and cryogenic conditions, respectively. A novel mathematical model has been proposed to correlate the size distributions of solid particles under fracture to the temperature changes.

PRACTICAL APPLICATIONS

During the size reduction of solid food materials, intensive energy degradation into heat takes place during fracture before resulting into fragments. Because fracture is a rate process with random fluctuation of stresses, the thermal effects cannot be calculated from classical approaches. The article describes a novel approach to quantitatively characterize the thermal effects of solid food particulates in terms of temperature change as a function of particle size under different treatment conditions. These characterizations can serve as a principled basis for modeling effects in a field where classical approaches are not applicable. The proposed approach can also be extended to nanoparticle and molecular characterization, which otherwise necessitates the usage of expensive instrumentation and also in biological processing such as in cancer research wherein if the cell size and its material properties are known, it may be possible to control the temperature induced during cell division.
DEFINING STILL PARAMETERS USING CHEMCAD BATCH DISTILLATION MODEL FOR MODELING FRUIT SPIRITS DISTILLATIONS
Authors: CLAUS MICHAEL J. , BERGLUND KRIS A.
Published: December 2008

Fruit spirits production has always been and continues to be heavily dependent upon the sensory evaluation of the distillate by the distiller. Sensory fatigue can lead to many problems of analysis for the distiller during production. As such, it is desirable to have a method of analysis that is not heavily dependent upon the senses of the distiller. Modeling of the distillation process is difficult because of the number of components present in the fruit mash and distillate, as well as because of the constantly changing thermodynamic interactions present on each tray as a result of the batch distillation process. This paper identifies a method for identifying the still parameters needed to perform predictive modeling. This involves setting a distillate flow rate and reflux ratio, as well as time or volume cutoff frames of analysis. After identifying the still characteristics, it is possible to model the distillation using the CHEMCAD batch distillation program.

PRACTICAL APPLICATIONS

Utilizing computer modeling in distilled spirits production has the potential to improve quality control and reduce errors in the distillation process.
SUPERCRITICAL CARBON DIOXIDE SELECTIVITY TO FRACTIONATE PHENOLIC COMPOUNDS FROM THE DRY ETHANOLIC EXTRACT OF PROPOLIS
Authors: PAVIANI LOSIANE C. , DARIVA CLAUDIO , MARCUCCI MARIA C. , CABRAL FERNANDO A.
Published: December 2008

The global yield and composition of extracts obtained by supercritical carbon dioxide (SC‐CO2) extraction from a dry ethanolic extract of propolis were measured in order to determine the possibility of using SC‐CO2 to fractionate components of interest present in these extracts. The global yield extraction was measured, and also the concentrations of the following phenolic compounds in the resulting supercritical fluid extracts (SFEs): 3,5‐diprenyl‐4‐hydroxycinnamic acid (known as artepillin C), 3‐prenyl‐4‐hydroxycinnamic acid, 4‐hydroxycinnamic acid (p‐coumaric acid) and 4‐methoxy‐3,5,7‐trihydroxyflavone (kaempferide), of which artepillin C was the target component of greatest interest. The results showed extraction yields between 3.82 (at 150 bar) and 13.07% (at 350 bar), which could be highly correlated with the density of the SC‐CO2 at a constant temperature of 60C. The resulting concentrations in the SFE indicated that the selectivity of the carbon dioxide could be manipulated, and it was more selective at lower pressures, although with lower extraction yields.

PRACTICAL APPLICATIONS

Supercritical fluid extraction is an interesting process for the production of natural extracts because it is a clean process, and extractions using carbon dioxide (CO2) as the solvent have been gaining attention in recent years. This study presented important aspects with respect to the fractionation of a dry ethanolic extract of propolis using supercritical carbon dioxide, and it is important to explore the potential applications of propolis extracts and the biological properties of its fractions in the food, pharmaceutical and cosmetic industries, such as in dental hygiene products, wound healing creams and antibacterial soaps.
Do Children in Rural Areas Still Have Different Access to Health Care? Results from a Statewide Survey of Oregon's Food Stamp Population
Authors: DeVoe Jennifer E. , Krois Lisa , Stenger Rob
Published: December 2008

ABSTRACT: 
Purpose: To determine if rural residence is independently associated with different access to health care services for children eligible for public health insurance. Methods: We conducted a mail‐return survey of 10,175 families randomly selected from Oregon's food stamp population (46% rural and 54% urban). With a response rate of 31%, we used a raking ratio estimation process to weight results back to the overall food stamp population. We examined associations between rural residence and access to health care (adjusting for child's age, child's race/ethnicity, household income, parental employment, and parental and child's insurance type). A second logistic regression model controlled for child's special health care needs. Findings: Compared with urban children (reference = 1.00), rural children were more likely to have unmet medical care needs (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.07‐2.04), problems getting dental care (OR 1.36, 95% CI 1.03‐1.79), and at least one emergency department visit in the past year (OR 1.42, 95% CI 1.10‐1.81). After adjusting for special health care needs (more prevalent among rural children), there was no rural‐urban difference in unmet medical needs, but physician visits were more likely among rural children. There were no statistically significant differences in unmet prescription needs, delayed urgent care, or having a usual source of care. Conclusions: These findings suggest that access disparities between rural and urban low‐income children persist, even after adjusting for health insurance. Coupled with continued expansions in children's health insurance coverage, targeted policy interventions are needed to ensure the availability of health care services for children in rural areas, especially those with special needs.
Presence of a Community Health Center and Uninsured Emergency Department Visit Rates in Rural Counties
Authors: Rust George , Baltrus Peter , Ye Jiali , Daniels Elvan , Quarshie Alexander , Boumbulian Paul , Strothers Harry
Published: December 2008

ABSTRACT: 
Context: Community health centers (CHCs) provide essential access to a primary care medical home for the uninsured, especially in rural communities with no other primary care safety net. CHCs could potentially reduce uninsured emergency department (ED) visits in rural communities. Purpose: We compared uninsured ED visit rates between rural counties in Georgia that have a CHC clinic site and counties without a CHC presence. Methods: We analyzed data from 100% of ED visits occurring in 117 rural (non‐metropolitan statistical area [MSA]) counties in Georgia from 2003 to 2005. The counties were classified as having a CHC presence if a federally funded (Section 330) CHC had a primary care delivery site in that county throughout the study period. The main outcome measure was uninsured ED visit rates among the uninsured (all‐cause ED visits and visits for ambulatory care sensitive conditions). Poisson regression models were used to examine the relationship between ED rates and the presence of a CHC. To ensure that the effects were unique to the uninsured population, we ran similar analyses on insured ED visits. Findings: Counties without a CHC primary care clinic site had 33% higher rates of uninsured all‐cause ED visits per 10,000 uninsured population compared with non‐CHC counties (rate ratio [RR] 1.33, 95% confidence interval [CI] 1.11‐1.59). Higher ED visit rates remained significant (RR 1.21, 95% CI 1.02‐1.42) after adjustment for percentage of population below poverty level, percentage of black population, and number of hospitals. Uninsured ED visit rates were also higher for various categories of diagnoses, but remained statistically significant on multivariate analysis only for ambulatory care sensitive conditions (adjusted RR = 1.22, 95% CI 1.01‐1.47). No such relationship was found for ED visit rates of insured patients (RR 1.06, 95% CI 0.92‐1.22). Conclusions: The absence of a CHC is associated with a substantial excess in uninsured ED visits in rural counties, an excess not seen for ED visit rates among the insured.
Research and theory on high‐performance work systems: progressing the high‐involvement stream
Authors: Boxall Peter , Macky Keith
Published: December 2008

The notion of a high‐performance work system (HPWS) constitutes a claim that there exists a system of work practices for core workers in an organisation that leads in some way to superior performance. In this article, we dissect this fuzzy notion and examine its companion terminology: high‐involvement work systems and high‐commitment management. We argue that a focus on the high‐involvement stream usefully grounds HPWS studies in an important area of workplace change in the current context and takes us away from eclectic and contentious selections of ‘best practices’. We review research models and findings in this stream. The path to better research lies in examining the underpinning processes experienced by workers when management seeks to pursue high‐involvement systems, and charting their links to employee and operational outcomes.
HR, perceived organisational support and organisational identification: an analysis after organisational formation
Authors: Edwards Martin R.
Published: December 2008

Academic research has rarely investigated the role that people management plays in encouraging employees to identify with their employing organisation. This article reports on a study investigating the role that employee perceptions of the HR environment plays in encouraging organisational identification and the importance of perceived organisational support in this relationship. Two research surveys are discussed, one carried out shortly after the formation of the new organisation within the UK National Health Service, and one is a replication study undertaken 13 months later. The results show that key HR‐related factors predict organisational identification; this effect is both direct and indirect through perceptions of organisational support. The findings also demonstrate that, as the organisation matures, there are some interesting changes in which aspects of the HR environment predict identification and perceptions of organisational support.
Prospective cohort comparison of bioactive glass implants and conchal cartilage in reconstruction of the posterior canal wall during tympanomastoidectomy
Authors: Abramovich S. , Hannan S.A. , Huins C.T. , Georgalas C. , McGuinness J. , Vats A. , Thompson I.
Published: December 2008

Objective:  To compare the effectiveness of bioactive glass implants and conchal cartilage in reconstructing the posterior canal wall during tympanomastoidectomy.

Study design:  Prospective cohort clinical study.

Setting:  Teaching hospital.

Patients:  Patients with clinically diagnosed chronic suppurative otitis media and cholesteatoma awaiting tympanomastoidectomy were recruited.

Intervention:  All patients underwent tympanomastoidectomy by the same surgeon. A first cohort of 12 patients underwent posterior canal wall reconstruction with autogenous conchal cartilage. A second cohort of 12 patients underwent such reconstruction with prefabricated bioactive glass.

Main outcome measures:  Primary– All patients underwent out‐patient review at 1, 3, 6 and 12 months postoperatively, after which a second‐look procedure was performed. Reconstructions were inspected for evidence of epithelialization, granulation, infection, stenosis, depression and extrusion. Secondary– All patients had perioperative serial pure‐tone audiometry to check for any change in hearing levels upto 1 year postoperatively.

Results:  By 1 year postoperatively, both reconstructive graft materials showed good epithelialization, no granulation, no infection, no ear canal stenosis, no depression and no extrusion. At operative second‐looks, bioactive glass particularly showed good tissue bonding, including both neovascularization and connective tissue integration. Overall clinical outcome was equivalent for both materials. Both graft materials showed no statistically significant difference in postoperative hearing levels.

Conclusions:  Bioactive glass and conchal cartilage showed equivalent clinical outcome in reconstructing the posterior canal wall without significantly affecting hearing levels. As bioactive glass does not require second site morbidity and thus also reduces operative time, we prefer it for reconstructing the posterior canal wall following tympanomastoidectomy.
Altered expressions of trefoil peptides genes in squamous cell carcinoma of the larynx
Authors: Sipaul F. , Corfield A. , Wood S. , Upile T. , Sheffield E. , Birchall M.A.
Published: December 2008

Aim.  Trefoil peptides (TFF) are secretory products of mucin‐producing cells and influence the rheological properties of mucous gels.1 They are thought to be important for the repair of mucosa damage.2 We hypothesised that TFF genes would be expressed in laryngeal mucosa and that this would be altered by smoking and neoplasia.

Methods.  The expressions of TFF1‐3 were examined using 35S‐dATP in situ hybridisation. Biopsies were obtained from the supraglottic mucosa of non‐smokers (normal, n = 14) and smokers (smokers, n = 14) without laryngeal disease undergoing routine surgery and compared with tissue from archival squamous cell carcinoma (SCC: laryngectomy) specimens (n = 14). Autoradiographic intensity was scored (semi‐quantitatively) by two independent observers and compared to positive and negative control tissue.

Results.  Scores are medians for each gene.

TFF gene
Normal (n = 14)
Smokers (n = 14)
SCC (n = 14)

TFF1
0
0
+

TFF2
0/+
0
+

TFF3
++
+
++

Expression was scored as 0–+++; 0 = absent, +++ strongly positive.

Discussion.  Major expression of TFF3 and weak expression of TFF2 are found in normal laryngeal mucosa. TFF3 appears to be down‐regulated in smokers and then up‐regulated again in the cancer group (SCC). The significant findings are that TFF1 and 2 appear to be expressed or up‐regulated in the cancer group. These findings suggest that laryngeal squamous cell carcinogenesis is associated with abnormal TFF1 and TFF2 genes expressions.

References.  1 Kutta H., Steven P., Varoga D. et al. (2004) TFF peptides in the human false vocal folds of the larynx. Peptides. 25(5), 811–818

2 Taupin D. & Podolsky D.K. (2003) Trefoil factors: initiators of mucosal healing. Nat Rev Mol Cell Biol. 4(9), 721–732
The use of Nutlin‐3 as a radiosensitiser in laryngeal carcinoma cells harbouring wild‐type p53
Authors: Arya A.K. , Devlin T. , El‐Fert A. , Banfield M. , Rubbi C. , Lloyd B. , Fenwick J. , Jones T.M. , Boyd M.T.
Published: December 2008

Objectives.  Radiotherapy is one of the mainstays of treatment for squamous cell carcinoma of the larynx but is often associated with severe morbidity. Providing patients with targeted treatment according to tumour type is a major goal of clinicians treating the disease. It has previously been shown that p53 is a critical mediator of radiation response and thus we investigated its influence on radiosensitivity and also whether Nutlin‐3 (the small molecule inhibitor of p53/MDM2 interaction) could radiosensitise tumours.

Methods.  Seven cell lines derived exclusively from patients with laryngeal carcinoma and with defined p53 status (determined by direct sequencing of exons 2–11 and intron/exon boundaries) were examined. Radiosensitivity was determined by clonogenic assays following treatment with gamma irradiation in the presence and absence of Nutlin‐3. Flow cytometry was used to determine cell cycle characteristics and the levels of apoptosis and senescence were also measured.

Results.  Cells with p53 homozygous mutations were relatively radiosensitive (SF2 < 20%). Cell lines with wild‐type p53, heterozygous and homozygous non‐sense mutations were relatively radioresistant (SF2 > 60%). Wild‐type p53 cells were made significantly more radiosensitive after treatment with Nutlin‐3. Neither apoptosis nor cell cycle responses corresponded with radiosensitivity. Interestingly, cells that displayed senescence were radioresistant whereas those that did not were radiosensitive suggesting a possible role for senescence in determining radiosensitivity.

Conclusions.  This is the first study to demonstrate that Nutlin‐3 may be an effective radiosensitiser in laryngeal cancer cell lines with wild‐type p53. The clinical application of Nutlin‐3 might improve survival rates or reduce therapeutic doses in these patients.
Proteomic analysis of metastatic laryngeal squamous cell carcinoma
Authors: Goodyear P.W.A. , Boyd M.T. , Jenkins R. , Hamlett J. , Kitteringham N. , Jones T.M.
Published: December 2008

Objectives.  Patients presenting with head and neck cancer may have no clinical or radiological evidence of cervical lymph node metastasis – the N0 neck. Despite this, histo‐pathological data has confirmed the presence of occult metastases in up to 30% of N0 necks (i.e. N+), depending on the site of the primary tumour. Currently there is no way of identifying affected individuals and consequently, 70% may be overtreated.1 Using proteomic and immuno‐histochemical (IHC) techniques, we attempted to identify a primary tumour phenotype, which would allow the discrimination of laryngeal squamous cell carcinoma (LSCC) with metastatic potential.

Method.  Six fresh frozen primary LSCC samples; three each from patients with a histopathologically confirmed N+ or N0 neck were used. Following homogenisation of the tumour tissue, protein separation using 2D gel electrophoresis was performed. Differences in individual protein expression between N0 and N+ groups were identified using Progenesis SameSpots® gel analysis software. Differentially expressed proteins were extracted from the gels and identification was achieved using a combination of matrix‐assisted laser desorption and ionization mass spectrometry (MS) (MALDI) and liquid chromatography tandem MS (LC‐MS/MS).

Results.  Ten strongly differentially expressed proteins were identified. Those identified included heat shock protein 90, T complex protein 1 gamma, Bromodomain PHD finger protein 3 and lactate dehyrogenase A, which were up‐regulated and thymidine phosphorylase which was down‐regulated in N+ samples.

Conclusions.  These proteins represent potential biomarkers of metastatic potential in LSCC. Further investigation of their worth as biomarkers is necessary using, in the first instance, large sample tissue microarrays.

Reference. 1 Yarbrough W.G., Slebos R.J.C. & Liebler D. (2006) Proteomics: clinical applications for head and neck squamous cell carcinoma. Head Neck. 28, 549–558
Raised EGFR in combination with low cyclin D1 is associated with radioresistance in laryngeal carcinoma cells
Authors: Banfield M.C. , Arya A.K. , Behrendt A. , El‐Fert A. , Devlin T. , Rubbi C. , Munir N. , Boyd M.T. , Jones T.M.
Published: December 2008

Introduction.  Radiotherapy is one of the mainstays of treatment for squamous cell carcinoma. Identifying tumour markers able to predict tumour sensitivity to radiotherapy could enable patient/tumour specific treatment targeting and/or dose modification. In a recent study we demonstrated that high levels of EGFR and cyclin D1 were associated with disease recurrence after radiotherapy for patients with T2 laryngeal cancer.1 The aim of this study was to investigate this relationship in a panel of cell lines derived from laryngeal squamous cell carcinomas (LSCC).

Methods.  Six LSCC cell lines were exposed to 2Gy of gamma irradiation from a 147Caesium source. Following irradiation, a clonogenic assay was used to define the relative radiosensitivity (SF2) of each cell line. Western blot analysis, followed by densitometry measurement, was used to determine the relative expression of EGFR and cyclin D1 in each cell line.

Results.  Levels of EGFR and cyclin D1 were individually not strongly predictive for radiosensitivity. However, cell lines with a combination of high expression of EGFR and low expression of cyclin D1 were found to correlate strongly with a radioresistant phenotype (P = 0.95).

Conclusions.  This study accords with previous evidence that the cyclin D1/ EGFR axis is important in determining radiation susceptibility. However, in contrast to previous work we found that low, as opposed to high levels of cyclin D1, were associated with radioresistance. Our studies provide an opportunity for functional investigation of the roles of EGFR and cyclin D1 in determining radioresistance in LSCC cells.
The effect of macrolides on allergic rhinitis versus chronic rhinosinusitis – An in vitro study
Authors: Kuchai R. , Wedzicha W. , Alusi G.
Published: December 2008

Objectives.  The aims of this study were to explore the differences in the pathophysiological mechanisms of allergic rhinitis and chronic rhinosinusitis and their interactions with macrolides. The first hypothesis is that there are fundamental differences in the process that results in allergic rhinitis and chronic rhinosinusitis. These differences were investigated by analysing baseline levels of cytokine and subsequent effects of bacterial endotoxin on human nasal epithelial cells (HNECs) within three patient subgroups:‐Normal (non‐atopic); allergic rhinitics and chronic rhinosinusitics. The second hypothesis is that there is a difference in the cytokine responses mounted by macrolides in allergic rhinitis, chronic rhinosinusitis. A comparative study of cytokine reactivity in these three groups has not previously been undertaken.

Method.  Human nasal epithelial cells were grown from nasal turbinate biopsy as explant cultures. Nasal tissue was obtained from three groups of patients:‐ (1). Normal, non‐atopics (2). Allergic rhinitics (AR) (3). Chronic rhinosinusitics(CRS). The HNECs were stimulated by LPS endotoxin and then exposed to macrolides.

Results.  Erythromycin significantly reduced IL‐6 and IL‐8 levels (P < 0.05) in allergic rhinitics as well as unstimulated CRS. LPS had no significant effect on stimulated CRS however significantly reduced IL‐6 and IL‐8 in unstimulated cells. Erythromycin may either inhibit the expression or release of these inflammatory mediators.

Conclusions.  The results help formulate an improved understanding of potential anti‐inflammatory effects and thereby potential applications in the management of both allergic rhinitis and chronic rhinosinosinusitis. The anti‐inflammatory effects of erythromycin require further in vivo analysis.
Progress in the Understanding of the Genetic Etiology of Vertebral Segmentation Disorders in Humans
Authors: Giampietro Philip F. , Dunwoodie Sally L. , Kusumi Kenro , Pourquié Olivier , Tassy Olivier , Offiah Amaka C. , Cornier Alberto S. , Alman Benjamin A. , Blank Robert D. , Raggio Cathleen L. , Glurich Ingrid , Turnpenny Peter D.
Published: December 2008

Vertebral malformations contribute substantially to the pathophysiology of kyphosis and scoliosis, common health problems associated with back and neck pain, disability, cosmetic disfigurement, and functional distress. This review explores (1) recent advances in the understanding of the molecular embryology underlying vertebral development and relevance to elucidation of etiologies of several known human vertebral malformation syndromes; (2) outcomes of molecular studies elucidating genetic contributions to congenital and sporadic vertebral malformation; and (3) complex interrelationships between genetic and environmental factors that contribute to the pathogenesis of isolated syndromic and nonsyndromic congenital vertebral malformation. Discussion includes exploration of the importance of establishing improved classification systems for vertebral malformation, future directions in molecular and genetic research approaches to vertebral malformation, and translational value of research efforts to clinical management and genetic counseling of affected individuals and their families.
Effect of Oxygen Concentration on Photo‐oxidation and Photosensitizer Bleaching in Butter
Authors: Wold Jens Petter , Veberg Dahl Annette , Lundby Frank , Nilsen Asgeir Nikolai , Juzeniene Asta , Moan Johan
Published: December 2008

The effect of headspace oxygen concentration and color of light on photo‐oxidation and degradation of photosensitizers in butter was studied. Butter samples were stored under 0%, 0.4%, 0.8%, 1.6%, 3.0%, 5.0%, 21% oxygen, and exposed to violet, green or red light. Storage time was 36 h. Degree of photo‐oxidation was measured by a trained sensory panel. Photobleaching of six different photosensitizers was estimated based on front face fluorescence excitation and emission landscapes and spectral curve resolution (parallel factor analysis). The higher oxygen concentration, the more sensory degraded were the samples. Violet light resulted in slightly higher degrees of photo‐oxidation than green and red light for low oxygen concentrations. Bleaching rate and course as function of O2 concentration differed between the photosensitizers. It is suggested that the rate of photobleaching is a balance between type I and type II photoreactions.
Simple Photodynamic Therapy Dose Models Fail to Predict the Survival of MLL Cells After HPPH–PDTIn Vitro
Authors: Weston Mark A. , Patterson Michael S.
Published: December 2008

Fluorescence photobleaching, photodynamic therapy (PDT) oxygen consumption and clonogenic cell survival were investigated during 2‐(1‐hexyloxethyl)‐2‐devinyl pyropheophoribde‐a (HPPH) PDT of MAT‐LyLu cellsin vitro. Cells were incubated with HPPH concentrations of 0.24, 1.2, 3.6 or 12 μmfor 4 h and then treated with 650 nm light under oxygenated and hypoxic conditions. Fluorescence spectra were acquired during treatment and photobleaching was quantified using singular value decomposition of the spectra. Cell survival was measured at set times during the treatment using a colony forming assay. Intracellular fluorescence lifetime measurements were also performed at each incubation concentration. The photobleaching kinetics did not follow first‐ or second‐order kinetics and the fluorescence lifetime was similar for all intracellular concentrations. As the intracellular concentration of drug was increased, the amount of singlet oxygen and the absorbed quanta per cell required to achieve the same cell kill increased. Singlet oxygen dose was calculated using one‐ and two‐compartment models of HPPH intracellular distribution. It was found that a two‐compartment model, in which a PDT‐sensitive binding site saturates at low concentrations, accounts for the observed photobleaching, oxygen consumption and cell survival.
Depth Profile of Protoporphyrin IX Fluorescence in an Amelanotic Mouse Melanoma Model
Authors: Juzenas Petras , Juzeniene Asta , Iani Vladimir , Moan Johan
Published: December 2008

Protoporphyrin IX (PpIX) fluorescence was measured at different depths in a subcutaneous amelanotic melanoma model (LOX) in mice. PpIX was induced by topical application of 5‐aminolevulinic acid (ALA) and two of its derivatives, the methylester (MAL) and hexylester (HAL) onto the normal skin covering the tumor. The PpIX fluorescence intensity on the surface of the tumors was the highest for HAL, followed by ALA and MAL. Using equimolar concentrations (0.5 mmol g−1), HAL induced nearly twice as much fluorescence as ALA did. The depth profile of PpIX fluorescence was measured at different layers of the tumor, which was carefully sliced and controlled in situ ex vivo. The PpIX fluorescence was mainly localized within the upper 2 mm of the tissue for ALA and within 1 mm for MAL and HAL. There were no significant differences in the shape of the fluorescence excitation spectra, but the long wavelength excitation peak (633 nm) was so weak that these results are unreliable for depth estimation. When considering the low fluorescence intensity (around 5% of the intensity at the tumor surface), the actual penetration depth of HAL was comparable to that of ALA. The fluorescence after topical application of ALA and HAL was significantly above the background level down to a depth of around 6 mm, and there were traces of PpIX fluorescence even at the tumor base (10 mm). The fluorescence after topical application of MAL was detectable down to 1 mm. In the depth of 2–6 mm, the fluorescence was slightly higher for HAL than for ALA. Using the estimated diffusion coefficients for topically applied ALA (0.16 ± 0.03 mm2 h−1), MAL (0.045 ± 0.005 mm2 h−1) and HAL (0.037 ± 0.003 mm2 h−1), the behavior of the drugs after different application times could be estimated in this tumor model.