bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of microRNAs in cephalochordates reveals a correlation between microRNA repertoire homology and morphological similarity in chordate evolution
Authors: Dai Zhonghua , Chen Zuozhou , Ye Hua , Zhou Longhai , Cao Lixue , Wang Yiquan , Peng Sihua , Chen Liangbiao
Published: January 2009

SUMMARY
Cephalochordates, urochordates, and vertebrates comprise the three extant groups of chordates. Although higher morphological and developmental similarity exists between cephalochordates and vertebrates, molecular phylogeny studies have instead suggested that the morphologically simplified urochordates are the closest relatives to vertebrates. MicroRNAs (miRNAs) are regarded as the major factors driving the increase of morphological complexity in early vertebrate evolution, and are extensively characterized in vertebrates and in a few species of urochordates. However, the comprehensive set of miRNAs in the basal chordates, namely the cephalochordates, remains undetermined. Through extensive sequencing of a small RNA library and genomic homology searches, we characterized 100 miRNAs from the cephalochordate amphioxus, Branchiostoma japonicum, and B. floridae. Analysis of the evolutionary history of the cephalochordate miRNAs showed that cephalochordates possess 54 miRNA families homologous to those of vertebrates, which is threefold higher than those shared between urochordates and vertebrates. The miRNA contents demonstrated a clear correlation between the extent of miRNA overlapping and morphological similarity among the three chordate groups, providing a strong evidence of miRNAs being the major genetic factors driving morphological complexity in early chordate evolution.
The deep evolution of metazoan microRNAs
Authors: Wheeler Benjamin M. , Heimberg Alysha M. , Moy Vanessa N. , Sperling Erik A. , Holstein Thomas W. , Heber Steffen , Peterson Kevin J.
Published: January 2009

SUMMARYmicroRNAs (miRNAs) are approximately 22‐nucleotide noncoding RNA regulatory genes that are key players in cellular differentiation and homeostasis. They might also play important roles in shaping metazoan macroevolution. Previous studies have shown that miRNAs are continuously being added to metazoan genomes through time, and, once integrated into gene regulatory networks, show only rare mutations within the primary sequence of the mature gene product and are only rarely secondarily lost. However, because the conclusions from these studies were largely based on phylogenetic conservation of miRNAs between model systems likeDrosophilaand the taxon of interest, it was unclear if these trends would describe most miRNAs in most metazoan taxa. Here, we describe the shared complement of miRNAs among 18 animal species using a combination of 454 sequencing of small RNA libraries with genomic searches. We show that the evolutionary trends elucidated from the model systems are generally true for all miRNA families and metazoan taxa explored: the continuous addition of miRNA families with only rare substitutions to the mature sequence, and only rare instances of secondary loss. Despite this conservation, we document evolutionary stable shifts to the determination of position 1 of the mature sequence, a phenomenon we call seed shifting, as well as the ability to post‐transcriptionally edit the 5′ end of the mature read, changing the identity of the seed sequence and possibly the repertoire of downstream targets. Finally, we describe a novel type of miRNA in demosponges that, although shows a different pre‐miRNA structure, still shows remarkable conservation of the mature sequence in the two sponge species analyzed. We propose that miRNAs might be excellent phylogenetic markers, and suggest that the advent of morphological complexity might have its roots in miRNA innovation.
Anatomical transformation in mammals: developmental origin of aberrant cervical anatomy in tree sloths
Authors: Buchholtz Emily A. , Stepien Courtney C.
Published: January 2009

SUMMARY
Mammalian cervical count has been fixed at seven for more than 200 million years. The rare exceptions to this evolutionary constraint have intrigued anatomists since the time of Cuvier, but the developmental processes that generate them are unknown. Here we evaluate competing hypotheses for the evolutionary origin of cervical variants in Bradypus and Choloepus, tree sloths that have broken the seven cervical vertebrae barrier independently and in opposite directions. Transitional and mediolaterally disjunct anatomy characterizes the cervicothoracic vertebral boundary in each genus, although polarities are reversed. The thoracolumbar, lumbosacral, and sacrocaudal boundaries are also disrupted, and are more extreme in individuals with more extreme cervical counts. Hypotheses of homologous, homeotic, meristic, or associational transformations of traditional vertebral column anatomy are not supported by these data. We identify global homeotic repatterning of abaxial relative to primaxial mesodermal derivatives as the origin of the anomalous cervical counts of tree sloths. This interpretation emphasizes the strong resistance of the “rule of seven” to evolutionary change, as morphological stasis has been maintained primaxially coincident with the generation of a functionally longer (Bradypus) or shorter (Choloepus) neck.
Selection on defensive traits in a sterile caste – caste evolution: a mechanism to overcome life‐history trade‐offs?
Authors: Roux Estelle A. , Roux Maurice , Korb Judith
Published: January 2009

SUMMARY
During development and evolution individuals generally face a trade‐off between the development of weapons and gonads. In termites, characterized by reproductive division of labor, a caste evolved—the soldiers—which is completely sterile and which might be released from developmental trade‐offs between weapons and testes. These soldiers are exclusively dedicated to defense. First, we investigated whether defensive traits are under selection in sterile termite soldiers using allometric analyses. In soldiers of the genus Cryptotermes phragmotic traits such as a sculptured and foreshortened head evolve rapidly but were also lost twice. Second, we compared the scaling relationships of these weapons with those in solitary insects facing a trade‐off between weapons and gonads. Defensive traits consistently had lower slopes than nondefensive traits which supports the existence of stabilizing selection on soldier phragmotic traits in order to plug galleries. Moreover, soldier head widths were colony specific and correlated with the minimum gallery diameter of a colony. This can proximately be explained by soldiers developing from different instars. The scaling relationships of these termite soldiers contrast strikingly with those of weapons of solitary insects, which are generally exaggerated (i.e., overscaling) male traits. These differences may provide important insights into trait evolution. Trade‐offs constraining the development of individuals may have been uncoupled in termites by evolving different castes, each specialized for one function. When individuals in social insect are “released” from developmental constraints through the evolution of castes, this certainly contributed to the ecological and evolutionary success of social insects.
Methods for the analysis of developmental sequence data
Authors: Maxwell Erin E. , Harrison Luke B.
Published: January 2009

SUMMARY
Heterochrony, evolutionary changes in developmental timing, can be studied either by examining changes in growth or changes in the sequence of developmental events. Developmental sequence data has the potential to address many important questions in the field of developmental evolution, but methodological challenges remain due to the biological and logical dependence of events in a ranked sequence. In the past 10 years, the study of sequence heterochrony has undergone a rebirth, with the creation of several new methods for the analysis of this type of data. These methods can be divided into two broad categories: phenetic comparisons between terminal taxa that strive to uncover integrations within the developmental sequences and putative shared sequence heterochronies, and phylogeny‐based methods that derive ancestor‐descendent sequence heterochronies and establish statements of sequence evolution. In this review, we will discuss the strengths and weaknesses of the methodologies that have been proposed to quantitatively examine developmental sequence data, and studies that have attempted to implement them in an evolutionary context.
HABITAT DIFFERENCES IN THE TIMING OF REPRODUCTION OF THE INVASIVE ALGASARGASSUM MUTICUM(PHAEOPHYTA, SARGASSACEAE) OVER TIDAL AND LUNAR CYCLES1
Authors: Monteiro Carla , Engelen Aschwin H. , Serrão Ester A. , Santos Rui
Published: January 2009

Sargassum muticum(Yendo) Fensholt is an invasive species that is firmly established on intertidal and subtidal rocky shores of Europe and the Pacific coast of North America. Local success and spread ofS. muticumis thought to rely on its reproductive potential that seems dependent on exogenous factors like tidal and lunar cycles. This study is the first to compare the reproductive patterns (periodicity of egg expulsion and embryo settlement) of this invader in two different habitats: the middle and low intertidal. The combination of monthly, daily, and tidal samples at triplicate sites within each habitat showed a semilunar periodicity of egg expulsion and embryo settlement coincident with increasing tidal amplitude just before full and new moons. In both habitats, duration of each egg expulsion event was ∼1 week, and embryo settlement occurred during the first daily low tide and with the incoming high tide during spring tides. However, both expulsion and settlement started 1–2 d earlier, expulsion saturation was faster, and settlement was higher in the mid‐ compared to the low intertidal. Our results suggest that the exact timing of gamete expulsion and embryo release ofS. muticumresponds to local factors, including tidal cues, which result in differences between mid‐ and low‐intertidal habitats.
Price Clustering: Evidence Using Comprehensive Limit‐Order Data
Authors: Chiao Chaoshin , Wang Zi‐May
Published: January 2009

Employing comprehensive limit‐order data which identify investor types, this paper examines the clustering pattern of limit‐order prices. First, limit orders, particularly those submitted by individual investors (IIs), tend to cluster at integer and even prices. Second, nonmarketable limit‐order prices cluster more than marketable limit‐order prices, indicating that aggressive limit orders generally embed more information. Third, investors choosing even‐priced limit orders are not penalized by lower execution ratios. Fourth, investors (particularly IIs) strategically exhibit front‐running behavior. Fifth, price clustering indeed creates price barriers. Finally, the degree of price clustering using trade data is significantly underestimated, compared to that using limit‐order data.
Short Selling and the Weekend Effect in Nasdaq Stock Returns
Authors: Christophe Stephen E. , Ferri Michael G. , Angel James J.
Published: January 2009

We examine daily short selling of Nasdaq stocks to explore whether speculative short selling causes a significant portion of the weekend effect in returns. We identify a weekend effect in speculative short selling whereby it constitutes a larger percentage of trading volume on Mondays versus Fridays. We find an opposite effect in dealer short selling, consistent with market makers adding liquidity and stability. Our main finding is that speculative short selling does not explain an economically meaningful portion of the weekend effect in returns, even among the firms most that are most actively shorted. This finding contradicts some prior studies.
Pedigree or Placement? An Analysis of Research Productivity in Finance
Authors: Chan Kam C. , Chen Carl R. , Fung Hung‐Gay
Published: January 2009

We examine pedigree and placement effects of research productivity in finance and find a notable placement effect: authors who are currently affiliated with “elite” institutions tend to be more productive, especially among the top three finance journals. The placement effect, however, weakens in more recent years. We also observe a pedigree effect in the top three journals, where there is a higher concentration of publications by authors with degrees from “elite” institutions. We provide rankings of the institutions that are best at developing and training scholars.
Entrepreneurial Financing and Costly Due Diligence
Authors: Yung Chris
Published: January 2009

In the traditional solution to the adverse selection problem, entrepreneurs indirectly signal quality via security choice, typically debt. This paper models an alternative solution. The costly due diligence of venture capitalists directly reveals the quality of projects, thereby reducing information asymmetry. It is shown that this mechanism necessitates profit‐sharing, a contractual feature usually associated in the literature with managerial agency costs rather than adverse selection.
Mesenchymal stem cells induce a weak immune response in the rat striatum after allo or xenotransplantation
Authors: Rossignol Julien , Boyer Cécile , Thinard Reynald , Remy Séverine , Dugast Anne‐Sophie , Dubayle David , Dey Nicolas D. , Boeffard Françoise , Delecrin Joël , Heymann Dominique , Vanhove Bernard , Anegon Ignacio , Naveilhan Philippe , Dunbar Gary L. , Lescaudron Laurent
Published: January 2009

Mesenchymal stem cells (MSCs) have attracted attention for their potential use in regenerative medicine such as brain transplantation. As MSCs are considered to be hypoimmunogenic, transplanted MSCs should not trigger a strong host inflammatory response. To verify this hypothesis, we studied the brain immune response after transplantation of human or rat MSCs into the rat striatum and MSC fate at days 5, 14, 21 and 63 after transplantation. Flow cytometry analysis indicated that both MSCs express CD90 and human leucocyte antigen (MHC) class I, but no MHC class II molecules. They do not express CD45 or CD34 antigens. However, MSC phenotype varies with passage number. Human MSCs have mRNAs for interleukin (IL)‐6, IL‐8, IL‐12, tumour necrosis factor (TNF)‐α and TGF‐β1, whereas rat MSCs express IL‐6‐, IL‐10‐, IL‐12‐ and TGF‐β1‐mRNAs. The quantification shows higher levels of mRNAs for the anti‐inflammatory molecules IL‐6 and TGF‐β1 than for pro‐inflammatory cytokines IL‐8 and IL‐12; ELISA analysis showed no IL‐12 whereas TGF‐β1 and IL‐6 were detected. Transplant size did not significantly vary between 14 and 63 days after transplantation, indicating an absence of immune rejection of the grafts. Very few mast cells and moderate macrophage and microglial infiltrations, observed at day 5 remained stable until day 63 after transplantation in both rat and human MSC grafts. The observations of very few dendritic cells, T αβ‐cells, and no T γδ‐lymphocytes, all three being associated with Tp rejection in the brain, support the contention that MSCs are hypoimmunogenic. Our results suggest that MSCs are of great interest in regenerative medicine in a (xeno)transplantation setting.
Oncogenesis and cancer stem cells: current opinions and future directions
Authors: Cheng Xiaoyu , O’Neill Helen C.
Published: January 2009

Introduction

Stem cells and haematopoiesis

The cancer stem cell hypothesis

Evidence form leukaemias and solid tumours

Cellular origin and the role of the niche

Molecular basis of self‐renewal and differentiation

Concluding remarks: cancer stem cells as a target for new cancer therapy

There is increasing evidence to show that only a subset of cancer cells drives the growth and progression of a tumour. These cells share similar properties with normal stem cells and are termed ‘cancer stem cells’. Cancer stem cells have been identified in acute myeloid leukaemia and in some solid tumours by their distinct expression of cell surface antigens. Their long‐term, self‐renewing capacity is thought to be a determining factor in the maintenance and regrowth of the tumour. Studies on haematopoietic cancers show that important signalling pathways and genes for normal haematopoiesis, such as Wnt, NF‐κB, Notch, hedgehog (Hh) and Bmi1, are oncogenic, thereby potentially involved in cancer stem cell regulation. Elimination of cancer stem cells in tumours could result in the degeneration of downstream cells, which makes them potential targets for new cancer therapies.
Congenital diaphragmatic hernia: an overview of the etiology and current management
Authors: Gaxiola Alejandra , Varon Joseph , Valladolid Genaro
Published: January 2009

Aim: To review provide an overview of the etiology and current strategies in the management of congenital diaphragmatic hernia (CDH).

Methods: We did a comprehensive review of research trends, evidence based studies and epidemiologic studies.

Results: CDH is a life‐threatening pathology in infants, and a major cause of death due to the pulmonary hypoplasia and pulmonary hypertension. There is much research related to elucidating the etiology of CDH and developing management strategies to improve the outcomes in these infants.

Conclusion: An early diagnosis with increased understanding of this disease is a crucial factor for a timely approach to managing the critically ill infant, and to offer the potential for improved outcomes and substantial reductions in morbidity.
Negotiating a New Role in a Gendered Order: A Cultural Lens
Authors: Golden‐Biddle Karen , Reay Trish
Published: January 2009

This article examines how advocates for the nurse practitioner (NP) role negotiated its implementation in a large urban health system that differentiates nursing from medicine on the basis of gender. Using a cultural perspective, analyses show how advocates envisioned the NP role as liminal—neither traditional nursing nor medical—and as expanding the boundaries of nursing work through appropriation of some medical work. Four key negotiation strategies are profiled that advocates used to successfully implement and sustain this role in most settings. The conclusion examines whether and how this new role altered or maintained the gendered arrangements and more generally points to the significance of liminal phenomena in producing fundamental change.
Gendered Bodies: Negotiating Normalcy and Support
Authors: Putnam Linda L. , Bochantin Jaime
Published: January 2009

Research on gender and negotiation typically focuses on formal bargaining about salary and compensation. This work needs to be expanded to everyday negotiations in the workplace, especially negotiations on organizational issues deemed germane to women. Drawing from research on work‐life issues, this study focuses on how women frame problems about menopause at work in ways that make them open to negotiation. Specifically, it examines message board posts on an online discussion board to see how issues are named, blamed, and claimed and how this framing situates them as interests, rights, or power concerns that foster or hinder opportunities for negotiation.
A Rainbow Coalition or Separate Wavelengths? Negotiations Among Employee Network Groups
Authors: Scully Maureen A.
Published: January 2009

Employee network groups are increasingly common in the workplace, such as a women’s network, an African American caucus, or a GLBT resource group. These groups may seem like natural allies for addressing inequality at work, particularly subtle forms of second generation discrimination. However, they often compete for attention, resources, and the limited political will of top managers to make changes. This article examines four cases in which employee groups were able to negotiate effective alliances across their own differences. They do so by reframing areas of shared interests, using and adapting social movement tactics, and reaching for outcomes with broader societal significance for equal economic opportunity.
Gendered Organizational Order and Negotiations Research
Authors: Sondak Harris , Stuhlmacher Alice F.
Published: January 2009

The study of negotiations can be informed by conceptualizing gender, as well as negotiation, within the larger organizational and societal order. Expanding the definition of negotiation and gender begins with consideration of who negotiates, what is negotiated, when negotiations are undertaken, how negotiations proceed, and finally, why this research proceeds. By considering this broad set of questions, researchers can incorporate a wider range of perspectives about negotiation, gender, and organizational contexts into their work.
Effects of Light Exposure and Use of Intraocular Lens on Retinal Pigment Epithelial Cells In Vitro
Authors: Hui Sheng , Yi Lu , Fengling Qing L.
Published: January 2009

To investigate the effect of a blue light‐filtering intraocular lens (IOL) and a UV‐absorbing IOL on light‐induced damage to retinal pigment epithelial (RPE) cells laden with the lipofuscin fluorophore N‐retinylidene‐N‐retinylethanolamine (A2E), A2E‐laden RPE cells were exposed to white light which was filtered by either a blue light‐filtering IOL or a UV‐absorbing IOL. After 30 min of illumination the cell viability and the level of reactive oxygen species (ROS), free glutathione (GSH), vascular endothelial growth factor (VEGF) and pigment epithelium‐derived factor (PEDF) were determined. In the absence of an IOL, the white light exposure decreased cell viability to 37.2% of the nonirradiated control. The UV‐absorbing IOL tended to reduce light‐induced cell death; however, the decrease was not significant. The blue light‐filtering IOL significantly attenuated light‐induced cell damage, increasing cell viability to 79.5% of the nonirradiated control. The presence of the blue light‐filtering IOL significantly increased GSH and PEDF levels, and decreased ROS and VEGF levels. This study suggests that a blue light‐filtering IOL may be more protective against A2E‐induced light damage and inhibit more light‐induced ROS and VEGF production than a conventional UV‐absorbing IOL.
How do People Evaluate Objects? A Brief Review
Authors: Houwer Jan De
Published: January 2009

Evaluation can be defined either as the process of determining the liking of an object or as responding in an evaluative manner to objects. It can be studied by examining the evaluative responses that objects evoke. After justifying these definitions and this approach to the study of evaluation, I present a brief overview of what is known about the variables that influence evaluative responding. Finally, I describe the Associative‐Propositional Evaluation model as an example of a theory about the mental processes that are assumed to underlie evaluative responding.
Synthesis of glycine betaine from choline in the moderate halophile Halobacillus halophilus: co‐regulation of two divergent, polycistronic operons
Authors: Burkhardt Janin , Sewald Xaver , Bauer Bettina , Saum Stephan H. , Müller Volker
Published: January 2009

The moderately halophilic bacterium Halobacillus halophilus can synthesize glycine betaine from choline. Oxidation of choline is induced by salinity and repressed by exogenous glycine betaine. The genes encoding the choline dehydrogenase (gbsB) and the glycine betaine aldehyde dehydrogenase (gbsA) were identified and shown to constitute an operon. Divergent to this operon is another operon containing gbsR and gbsU that encode proteins with similarities to a transcriptional regulator and a glycine betaine‐binding protein respectively. Synthesis of the four Gbs proteins was strictly dependent on the choline concentration of the medium. Salinity was essential for the production of GbsB and increased the production of GbsA, GbsR and GbsU. Glycine betaine repressed the production of all four Gbs proteins with half maximal inhibition at 0.1 mM glycine betaine.
The gut microbiota of toll‐like receptor 2‐deficient mice exhibits lineage‐specific modifications
Authors: Albert Eric J. , Sommerfeld Katrin , Gophna Sharon , Marshall Jean S. , Gophna Uri
Published: January 2009

Mutations in toll‐like receptors that mediate bacterial recognition by the mammalian innate immune system have the potential to substantially alter the composition of an individual's microbiota. Here we tested this hypothesis by comparing the intestinal microbiota of toll‐like receptor 2‐deficient mice, both young and middle aged, with that of wild‐type mice of the same genetic background, housed together under specific pathogen‐free conditions. Bacterial DNA was extracted from mouse caecal tissue samples, amplified using universal bacterial 16S ribosomal RNA gene primers, and cloned into a plasmid vector. Insert‐containing colonies were picked for high‐throughput sequencing, and sequence data were analysed yielding species‐level phylogenetic data. Clone libraries were compared by phylogenetic composition analysis using UniFrac. While pairwise differences in phylogenetic population structure between mutant and wild‐type mice were not statistically significant, anosim analysis did demonstrate a significant difference between toll‐like receptor 2‐deficient mice and their wild‐type counterparts. The difference observed was probably due to a high level of colonization of the toll‐like receptor 2‐deficient mice by two distinct Helicobacter phylotypes that were totally absent from wild‐type mice. Principal coordinate analysis clustering indicated that age is a weaker determinate than genotype and maternal heritage in the mouse caecal microbiota. The findings suggest that although mutations in toll‐like receptors may cause increased susceptibility to specific opportunistic bacteria, they do not dramatically alter the phylogenetic structure of microbiota.
Prevalence and Risk Factors for Bacterial Food‐Borne Zoonotic Hazards in Slaughter Pigs: A Review
Authors: Fosse J. , Seegers H. , Magras C.
Published: January 2009

The Hygiene Package and Regulation EC‐2160/2003 require information flow from farm to slaughterhouse to enhance European consumers protection in a ‘farm to fork’ approach. This obligation especially concerns food‐borne zoonotic hazards transmitted to humans through pork consumption, such as thermophilicCampylobacterspp.,Listeria monocytogenes,Salmonella entericaandYersinia enterocolitica. Prevalence estimates of these four hazards are affected by the sampling strategy and diagnostic procedure. Individual prevalence estimates for pig carriage (from digestive contents or lymph nodes collected at slaughterhouse) were higher than individual prevalence estimates for pig shedding (from faeces). Among risk factors described in the literature, poor pen cleaning and disinfection after pig departure to slaughterhouse and poor bio‐security measures are of major significance. Moreover, whereas wet feed increases the risk of pig infection byL. monocytogenes, dry feed is a risk factor forSalm. enterica. Mixing batches of pigs, notably in fattening herds, represents a risk for the transmission ofSalm. entericaandY. enterocolitica. Whereas small herds are more infected by thermophilic campylobacters andY. enterocolitica, higher prevalence ofSalmonellais observed in large herds due to a more frequent mixing of batches. Antibiotic treatment during the finishing period increases the risk of transmission ofSalm. enterica. The forenamed elements should be taken into account to characterize farms in a risk assessment approach and to improve zoonotic hazard management in the pork food chain.
Risk Factors for Encephalitis from West Nile Virus: A Matched Case‐Control Study Using Hospitalized Controls
Authors: Murray K. O. , Koers E. , Baraniuk S. , Herrington E. , Carter H. , Sierra M. , Kilborn C. , Arafat R.
Published: January 2009

We conducted a case‐control study to determine risk factors for developing encephalitis among West Nile virus cases when compared with age‐, gender‐ and race/ethnicity‐matched hospitalized controls. In the multivariable conditional logistic regression analysis, we identified the following independent risk factors associated with being an encephalitis case: hypertension (OR 4.0; P = 0.005), immunosuppressing conditions (OR 5.6; P = 0.001) and cardiovascular disease (OR = 28.3; P < 0.001). Individuals with these comorbidities should be targeted for education on protecting themselves from mosquito exposures.
Occurrence of hepatocellular carcinoma after hepatoblastoma resection in an adult with hepatitis C virus
Authors: Masuda Toshiro , Beppu Toru , Horino Kei , Komori Hiroyuki , Hayashi Hiromitsu , Okabe Hirohisa , Ootao Ryuu , Horlad Hasita , Baba Yoshifumi , Miyase Shiho , Takamori Hiroshi , Baba Hideo
Published: January 2009

Hepatoblastoma is a rare malignancy in adults. It is often diagnosed after the appearance of symptoms, therefore, the tumor size tends to be larger. In patients with no indication for a hepatic resection, the prognosis of adult hepatoblastoma is quite poor. A 54‐year‐old man with hepatitis C virus‐associated liver cirrhosis was initially treated with a hepatic resection for a hepatic tumor, 3 cm in diameter. The tumor consisted of osteoid‐like and cartilaginous foci, myxomatous stroma, and poorly differentiated hepatocellular carcinomatous cells and was diagnosed as a mixed epithelial and mesenchymal hepatoblastoma. Two years after the first operation, multicentric hepatocellular carcinomas developed in the remnant liver and were successfully treated with a secondary hepatic resection combined with radio‐frequency ablation. The patient is now alive with no recurrence at 5 years after the initial hepatectomy. To the best of our knowledge, the primary hepatoblastoma was the smallest such tumor reported and this is the first report of a metachronous hepatoblastoma and hepatocellular carcinoma in an adult hepatitis patient.
Co‐ordination of spontaneous swallowing with respiratory airflow and diaphragmatic and abdominal muscle activity in healthy adult humans
Authors: Hårdemark Cedborg Anna I. , Sundman Eva , Bodén Katarina , Hedström Hanne Witt , Kuylenstierna Richard , Ekberg Olle , Eriksson Lars I.
Published: January 2009

Co‐ordination of breathing and swallowing is essential for normal pharyngeal function and to protect the airway. To allow for safe passage of a bolus through the pharynx, respiration is interrupted (swallowing apnoea); however, the control of airflow and diaphragmatic activity during swallowing and swallowing apnoea are not fully understood. Here, we validated a new airflow discriminator for detection of respiratory airflow and used it together with diaphragmatic and abdominal electromyography (EMG), spirometry and pharyngeal and oesophageal manometry. Co‐ordination of breathing and spontaneous swallowing was examined in six healthy volunteers at rest, during hypercapnia and when breathing at 30 breaths min–1. The airflow discriminator proved highly reliable and enabled us to determine timing of respiratory airflow unambiguously in relation to pharyngeal and diaphragmatic activity. During swallowing apnoea, the passive expiration of the diaphragm was interrupted by static activity, i.e. an ‘active breath holding’, which preserved respiratory volume for expiration after swallowing. Abdominal EMG increased throughout pre‐ and post‐swallowing expiration, more so during hyper‐ than normocapnia, possibly to assist expiratory airflow. In these six volunteers, swallowing was always preceded by expiration, and 93 and 85% of swallows were also followed by expiration in normo‐ and hypercapnia, respectively, indicating that, in man, swallowing during the expiratory phase of breathing may be even more predominant than previously believed. This co‐ordinated pattern of breathing and swallowing potentially reduces the risk for aspiration. Insights from these measurements in healthy volunteers and the airflow discriminator will be used for future studies on airway protection and effects of disease, drugs and ageing.
Acute volume expansion preserves orthostatic tolerance during whole‐body heat stress in humans
Authors: Keller David M. , Low David A. , Wingo Jonathan E. , Brothers R. Matthew , Hastings Jeff , Davis Scott L. , Crandall Craig G.
Published: January 2009

Whole‐body heat stress reduces orthostatic tolerance via a yet to be identified mechanism(s). The reduction in central blood volume that accompanies heat stress may contribute to this phenomenon. The purpose of this study was to test the hypothesis that acute volume expansion prior to the application of an orthostatic challenge attenuates heat stress‐induced reductions in orthostatic tolerance. In seven normotensive subjects (age, 40 ± 10 years: mean ±s.d.), orthostatic tolerance was assessed using graded lower‐body negative pressure (LBNP) until the onset of symptoms associated with ensuing syncope. Orthostatic tolerance (expressed in cumulative stress index units, CSI) was determined on each of 3 days, with each day having a unique experimental condition: normothermia, whole‐body heating, and whole‐body heating + acute volume expansion. For the whole‐body heating + acute volume expansion experimental day, dextran 40 was rapidly infused prior to LBNP sufficient to return central venous pressure to pre‐heat stress values. Whole‐body heat stress alone reduced orthostatic tolerance by ∼80% compared to normothermia (938 ± 152 versus 182 ± 57 CSI; mean ±s.e.m., P < 0.001). Acute volume expansion during whole‐body heating completely ameliorated the heat stress‐induced reduction in orthostatic tolerance (1110 ± 69 CSI, P < 0.001). Although heat stress results in many cardiovascular and neural responses that directionally challenge blood pressure regulation, reduced central blood volume appears to be an underlying mechanism responsible for impaired orthostatic tolerance in the heat‐stressed human.
Amphotericin B-Induced Renal Tubular Cell Injury Is Mediated by Na+Influx through Ion-Permeable Pores and Subsequent Activation of Mitogen-Activated Protein Kinases and Elevation of Intracellular Ca2+Concentration
Authors: Yano Takahisa , Itoh Yoshinori , Kawamura Eiko , Maeda Asuka , Egashira Nobuaki , Nishida Motohiro , Kurose Hitoshi , Oishi Ryozo
Published: January 2009

Amphotericin B (AMB) is one of the most effective antifungal agents; however, its use is often limited by the occurrence of adverse events, especially nephrotoxicity. The present study was designed to determine the possible mechanisms underlying the nephrotoxic action of AMB. The exposure of a porcine proximal renal tubular cell line (LLC-PK1 cells) to AMB caused cell injury, as assessed by mitochondrial enzyme activity, the leakage of lactate dehydrogenase, and tissue ATP depletion. Propidium iodide uptake was enhanced, while terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was not affected by AMB, suggesting a lack of involvement of apoptosis in AMB-induced cell injury. The cell injury was inhibited by the depletion of membrane cholesterol with methyl-β-cyclodextrin, which lowered the extracellular Na+concentration or the chelation of intracellular Ca2+. The rise in the intracellular Ca2+concentration may be mediated through the activation of the ryanodine receptor (RyR) on the endoplasmic reticulum and the mitochondrial Na+-Ca2+exchanger, since cell injury was attenuated by dantrolene (an RyR antagonist) and CGP37157 (an Na+-Ca2+exchanger inhibitor). Moreover, AMB-induced cell injury was reversed by PD169316 (a p38 mitogen-activated protein [MAP] kinase inhibitor), c-Jun N-terminal kinase inhibitor II, and PD98059 (a MEK1/2 inhibitor). The phosphorylations of these MAP kinases were enhanced by AMB in a calcium-independent manner, suggesting the involvement of MAP kinases in AMB-induced cell injury. These findings suggest that Na+entry through membrane pores formed by the association of AMB with membrane cholesterol leads to the activation of MAP kinases and the elevation of the intracellular Ca2+concentration, leading to renal tubular cell injury.
Use of a Bacteriophage Lysin, PlyC, as an Enzyme Disinfectant againstStreptococcus equi
Authors: Hoopes J. Todd , Stark Caren J. , Kim Han Ah , Sussman Daniel J. , Donovan David M. , Nelson Daniel C.
Published: January 2009

Streptococcus equiis the causative agent of the purulent infection equine strangles. This disease is transmitted through shedding of live bacteria from nasal secretions and abscess drainage or by contact with surfaces contaminated by the bacteria. Disinfectants are effective againstS. equi, but inactivation by environmental factors, damage to equipment, and toxicity are of great concern. Bacteriophage-encoded lysins (cell wall hydrolases) have been investigated as therapeutic agents due to their ability to lyse susceptible gram-positive organisms. Here, we investigate the use of one lysin, PlyC, as a narrow-spectrum disinfectant againstS. equi. This enzyme was active against >20 clinical isolates ofS. equi, including bothS. equisubsp.equiandS. equisubsp.zooepidemicus. Significantly, PlyC was 1,000 times more active on a per weight basis than Virkon-S, a common disinfecting agent, with 1 μg of enzyme able to sterilize a 108CFU/ml culture ofS. equiin 30 min. PlyC was subjected to a standard battery of tests including the Use Dilution Method for Testing Disinfectants and the Germicidal Spray Products Test. Results indicate that aerosolized PlyC can eradicate or significantly reduce theS. equiload on a variety of materials found on common stable and horse-related equipment. Additionally, PlyC was shown to retain full activity under conditions that mimic a horse stable, i.e., in the presence of nonionic detergents, hard water, or organic materials. We propose PlyC as the first protein-based, narrow-spectrum disinfectant againstS. equi, which may augment or supplement the use of broad-spectrum disinfectants in barns and stables where equine strangles is prevalent.
Coinfection with Two Closely Related Alphaherpesviruses Results in a Highly Diversified Recombination Mosaic Displaying Negative Genetic Interference
Authors: Muylkens Benoît , Farnir Frédéric , Meurens François , Schynts Frédéric , Vanderplasschen Alain , Georges Michel , Thiry Etienne
Published: January 2009

Phylogenetic studies of the emergence and spread of natural recombinants in herpesviruses infecting humans and animals have been reported recently. However, despite an ever-increasing amount of evidence of recombination in herpesvirus history, the recombination process and the consequences on the genetic diversity of the progeny remain poorly characterized. We addressed this issue by using multiple single-nucleotide polymorphisms (SNPs) differentiating the two subtypes of an alphaherpesvirus, bovine herpesvirus 1 (BoHV-1). Analysis of a large sample of progeny virions obtained in a single growth cycle of coinfected BoHV-1 strains provided a prospective investigation of the recombination dynamics by using SNPs as recombination markers. We found that the simultaneous infection with two closely related herpesviruses results in a highly diversified recombination mosaic. From the analysis of multiple recombinants arising in the progeny, we provide the first evidence of genetic interference influencing the recombination process in herpesviruses. In addition, we report striking differences in the levels of recombination frequency observed along the BoHV-1 genome. With particular emphasis on the genetic structure of a progeny virus population rising in vitro, our data show to which extent recombination participates to the genetic diversification of herpesviruses.
Eosinophilia-associated muscle disorders: an immunohistological study with tissue localisation of major basic protein in distinct clinicopathological forms
Authors: Cantarini L , Volpi N , Carbotti P , Greco G , Aglianò M , Bellisai F , Giannini F , Alessandrini C , Grasso G , Galeazzi M
Published: January 2009

Aims:

(a) To evaluate tissue eosinophil density, location of eosinophil cytotoxic products, histopathological muscle changes and inflammatory cell types in different eosinophilia-associated myopathies that are clinicopathologically heterogeneous. (b) To determine the immunohistological range of tissue eosinophil density in non-eosinophilic inflammatory myopathies.

Methods:

Muscle biopsy specimens from seven patients with blood and/or tissue eosinophilia and clinicolaboratory myopathic signs (five chronic course myopathies, one subacute onset fasciitis/myositis, one acute myositis), and from 18 non-eosinophilic inflammatory myopathies, underwent routine staining, inflammatory infiltrate immunophenotyping, immunostaining for eosinophil major basic protein (MBP) and transmission electron microscopy examination. Eosinophil and total inflammatory cell counts were statistically analysed.

Results:

Histological examination showed occasional or no infiltrating eosinophils in all cases. MBP staining showed that tissue eosinophil density and percentages in eosinophilia-associated myopathies were significantly higher than in idiopathic myositides. Extracellular MBP diffusion, the hallmark of eosinophil cytotoxicity, was recurrent on sarcolemma and endothelium. Electron microscopy showed eosinophils close to sarcolemma, abundant mast cells, and capillary endothelial swelling. Immunostaining detected a higher mean eosinophil density in idiopathic myositides than previously assessed histologically.

Conclusions:

MBP immunohistology on skeletal muscle, previously performed only for acute eosinophilic polymyositis, suggests that eosinophil-mediated injury of muscle cells may occur in a wider spectrum of less aggressive eosinophilia-associated myopathies than previously thought. As conventional histology is likely to underestimate this leucocyte subset, MBP staining may be a useful tool in the analysis of tissue infiltration of eosinophils as a possible treatment target.
Fungi and diseases — natural components of healthy forestsThis article is one of a collection of papers based on a presentation from the Stem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversity session of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.
Authors: Ostry M. E. , Laflamme G.
Published: January 2009

Forest health is described and perceived in different ways by the general public, land owners, managers, politicians, and scientists, depending on their values and objectives. Native tree pathogens and diseases are often associated with negative impacts even though damage is limited or not widespread. Too often, the concepts of tree health and forest health are used interchangeably and are not related to scale. Similar to fire, occurrences of disease outbreaks focus on the negative effects. However, native pathogens often exist in equilibrium with natural forest communities so their critical ecological roles are not easily discernible. Examined holistically, native fungi and diseases, dead and dying trees, and the many complex ecological interactions among them provide valuable benefits that ultimately contribute to sustainable, healthy forest ecosystems.
Determinants of parasitic plant distribution: the role of host qualityThis article is one of a collection of papers based on a presentation from theStem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversitysession of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.
Authors: Watson David M.
Published: January 2009

Parasitic plants are less affected by resource constraints than other plants and most exhibit broad host tolerances, occupy large distributional ranges, and produce high numbers of propagules. Yet, parasitic plants are characteristically rare in undisturbed habitats, and patterns of distribution within host populations are often highly nonuniform. Previous work on root and shoot parasites has identified strict germination requirements for many species but, while explaining host ranges and site–microsite preferences for particular species, this cannot account for the highly clumped spatial structure of many parasitic plant populations. Other research has examined the role of seed vectors, but in most systems studied, dispersers are not limiting and their dietary breadth, substrate use, habitat preferences, and distributional ranges exceed the extent of the parasitic plant. Here, I propose the “host-quality hypothesis,” suggesting that variation in the quality of potential hosts can account for nonrandom occurrence patterns of parasitic plants in many systems. “Quality” can relate to access to water, nutrients, or other resources that are generally limiting to hosts, whereby parasites are more likely to establish and survive on hosts with greater access (i.e., higher quality from the parasite’s perspective). Rather than supplanting germination requirements operating at the individual host plant scale or disperser behaviour operating at the landscape scale, this resource-based hypothesis applies at stand and population scales, explaining why some individuals within a stand or population are infected, while other apparently similar hosts are not susceptible. This hypothesis is explored using case studies on root and shoot hemiparasites, and is consistent with a diverse array of findings from a range of temperate and arid systems.
Contrasting research approaches to managing mistletoes in commercial forests and wooded pasturesThis minireview is one of a collection of papers based on a presentation from the Stem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversity session of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.
Authors: Reid Nick , Shamoun Simon F.
Published: January 2009

Many mistletoe species are pests in agricultural and forest ecosystems throughout the world. Mistletoes are unusual “weeds” as they are generally endemic to areas where they achieve pest status and, therefore, classical biological control and broad-scale herbicidal control are usually impractical. In North American coniferous forests, dwarf mistletoe ( Arceuthobium spp.) infection results in major commercial losses and poses a public liability in recreation settings. Hyperparasitic fungi have potential as biological control agents of dwarf mistletoe, including species which attack shoots, berries, and the endophytic systems of dwarf mistletoe. Development of an inundative biological control strategy will be useful in situations where traditional silvicultural control is impractical or undesirable. In southern Australia, farm eucalypts are often attacked and killed by mistletoes ( Amyema spp.) in grazed landscapes where tree decline and biodiversity loss are major forms of land degradation. Although long-term strategies to achieve a balance between mistletoe and host abundance are promoted, many graziers want short-term options to treat severely infected trees. Recent research has revisited the efficiency and efficacy of silvicultural treatments and selective herbicides in appropriate situations. The results of recent research on these diverse management strategies in North America and Australia are summarized.