bluuebunny/crossref_metadata_2025 huggingface dataset:
A Test of Numeric Formats for Communicating Risk Probabilities
Authors: Cuite Cara L. , Weinstein Neil D. , Emmons Karen , Colditz Graham
Published: May 2008

Background. Because people frequently encounter information about the probability of health risks, there is a need for research to help identify the best formats for presenting these probabilities. Methods. Three waves of participants were recruited from visitors to a cancer-related Internet site. Participants were presented with a hypothetical scenario that required them to perform 2 mathematical operations of the types that might be encountered in discussions of risk. Each wave encountered different operations. The operations used were compare, halve, triple, add, sequence, and tradeoff. Three numeric formats for communicating risk likelihoods were tested: percentages (e.g., 12%), frequencies (e.g., 12 in 100), and 1 in n (e.g., 1 in 8), and many levels of risk magnitude were crossed with the 3 formats. Results. The total sample of 16,133 individuals represented an overall participation rate of 36.1%. Although the relative performance of the formats varied by operation, aggregated across operations, the percentage and frequency formats had higher overall accuracy rates than the 1-in-n format (57% and 55% v. 45%, respectively). Participants with less education, African Americans, Hispanics, and women had more difficulty with the mathematical operations. Discussion. Percentage and frequency formats facilitate performance of simple operations on risk probabilities compared with the 1-in-n format, which should usually be avoided.
Quality Performance Measurement Using the Text of Electronic Medical Records
Authors: Pakhomov Serguei , Bjornsen Susan , Hanson Penny , Smith Steven
Published: May 2008

Background. Annual foot examinations (FE) constitute a critical component of care for diabetes. Documented evidence of FE is central to quality-of-care reporting; however, manual abstraction of electronic medical records (EMR) is slow, expensive, and subject to error. The objective of this study was to test the hypothesis that text mining of the EMR results in ascertaining FE evidence with accuracy comparable to manual abstraction. Methods. The text of inpatient and outpatient clinical reports was searched with natural-language (NL) queries for evidence of neurological, vascular, and structural components of FE. A manual medical records audit was used for validation. The reference standard consisted of 3 independent sets used for development (n=200 ), validation (n=118 ), and reliability (n=80 ). Results. The reliability of manual auditing was 91% (95% confidence interval [CI]= 85— 97) and was determined by comparing the results of an additional audit to the original audit using the records in the reliability set. The accuracy of the NL query requiring 1 of 3 FE components was 89% (95% CI= 83— 95). The accuracy of the query requiring any 2 of 3 components was 88% (95% CI= 82— 94). The accuracy of the query requiring all 3 components was 75% (95% CI= 68— 83). Conclusions. The free text of the EMR is a viable source of information necessary for quality of health care reporting on the evidence of FE for patients with diabetes. The low-cost methodology is scalable to monitoring large numbers of patients and can be used to streamline quality-of-care reporting.
Beyond the clearing: towards a dwelt animal geography
Authors: Johnston Catherine
Published: May 2008

This paper reviews recent developments at the intersection between culture—nature and animal geographies debates in order to consider the ways in which issues of anthropomorphism and beastliness have beset attempts to write the nonhuman. Seeking to move beyond the theoretical impasse that these two concepts have engendered, the paper explores engagement with the concept of dwelling developed by Ingold as a possible theoretical tool for a re-animated animal geography, one which seeks to take its cue from those individuals and groups whose lives depend on and are embedded in their daily connections and understandings with nonhumans.
Challenging heteronormativity in tourism studies: locating progress
Authors: Waitt Gordon , Markwell Kevin , Gorman-Murray Andrew
Published: May 2008

This article reviews work that challenges heteronormativity in tourism studies primarily from, but not restricted to, the discipline of geography. Indeed, tourism studies has benefited greatly from the growth of interdisciplinary research between geography, anthropology, sociology, as well as more recent interactions with queer, gender and leisure studies. In this context, as geographers, our aim is to use an explicitly geographical perspective to provide critical insights into recent research which contests, reinforces, or omits to challenge heteronormative positions in tourism studies. To this end, we provide four thematic `locations', or scales, through which to review progress of this inter-disciplinary and multi-disciplinary literature: the globalization of sexuality; marketing the (homo)sexualized nation; touring the (homo)sexualized city; and the tourist body as a gendered and sexed subject.
Categories, borders and boundaries
Authors: Jones Reece
Published: May 2008

In recent years, categories have been a topic of substantial research in the social sciences and humanities. Although many problematic categories such as culture, gender and scale have been criticized, moving beyond them has proved to be surprisingly difficult. This paper attributes this difficulty to what is termed the paradox of categories and argues that the key problems with categories emerge from the contradictory ways their boundaries are intellectually and cognitively understood. By integrating poststructural insights into the role categories play in ordering modern society with research from cognitive science on the role categories play as containers in cognitive processes, this paper argues that the boundaries of categories should be understood as always inchoate — only partially formed and incomplete. The paper concludes that research into categories and boundaries is unnecessarily fragmented across a wide range of disciplines and proposes expanding boundary studies in geography to be the field that investigates the bounding processes that result in all types of categories.
In Vitro Osteogenic Differentiation of Rat Mesenchymal Stem Cells in a Microgravity Bioreactor
Authors: Koç Aysel , Emin Nuray , Elçin A. Eser , Elçin Y. Murat
Published: May 2008

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the ability to differentiate into osteoblasts, chondroblasts, myocytes, and adipocytes. They have potential for bone tissue engineering by the utilization of in vitro expanded cells with osteogenic capacity and their delivery to the appropriate sites via biomaterial scaffolds. The objective was to evaluate the potential of rat bone marrow MSCs to form 3D bone-like tissue by the use of mineralized poly(DL-lactic-co-glycolic acid) (PLGA) foam and osteoinductive medium under rotating culture conditions. PLGA foams were prepared by solvent casting and particulate leaching, then mineralized by incubating in simulated body fluid. MSCs isolated from the bone marrow of young Wistar rats were expanded and seeded on the mineralized scaffolds. The cell-polymer constructs were then cultured in a slow turning lateral vessel-type rotating bioreactor for 4 weeks under the effect of osteogenic inducers, β-glycerophosphate, ascorbic acid and dexamethasone. Mineralization was evaluated using FT-IR and increases in dry mass; morphology changes of the mineralized foams and cell adhesion was characterized by SEM; cell viability was monitored by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide). Osteogenic differentiation was determined by using immunohistochemistry (anti-osteopontin). Results indicate the feasibility of bone tissue engineering with MSCs and mineralized PLGA scaffolds supporting cell adhesion, viability and osteogenic differentiation properties of cells in hybrid structures under appropriate bioreactor conditions.
Synthesis, Characterization, and Antibacterial Effects of Trimethylated and Triethylated 6-NH2-6-Deoxy Chitosan
Authors: Sadeghi A.M.M. , Amini M. , Avadi M.R. , Siedi F. , Rafiee-Tehrani M. , Junginger H.E.
Published: May 2008

Chitosan, a biodegradable and biocompatible polymer, has attracted great attention in the pharmaceutical and biomedical fields especially due to its properties to reversibly open the tight junctions of the epithelial tissues and to allow for paracellular transport of hydrophilic macromolecules. However, chitosan exhibits low solubility at pH values above 6 that may prevent its enhancing effects at the sites of intestinal absorption. Hence, a number of alkylated chitosan salts have been synthesized and characterized. These derivatives have been shown to have good solubility at neutral pH and act as effective permeation enhancers. In this study, two new derivatives of chitosan, C2—C6 trimethyl 6-amino-6-deoxy chitosan and C2—C6 triethyl 6-amino-6-deoxy chitosan were synthesized and characterized using 1H-NMR and FTIR spectra. Moreover, the zeta potential and the antibacterial properties of these polymers were compared to chitosan, trimethyl chitosan (TMC) and triethyl chitosan (TEC). Our results suggest that both C2—C6 trimethyl and triethyl 6-amino-6-deoxy chitosan, as highly water soluble polymers, have higher positive surface charge than chitosan, TMC, and TEC. Moreover, the new synthesized polymers show higher antibacterial activity against Gram-positive Staphylococcus aureus bacteria. Consequently, these polymers with substitution degrees of 50—60% may be good candidates for the enhancement of peptides in mucosal drug delivery.
Nutrition‐Focused Evaluation and Management of Dysnatremias
Authors: Whitmire Susan J.
Published: May 2008

Alterations in sodium and water balance are commonplace and often occur concurrently. Dysnatremias (hyponatremia and hypernatremia) merely reflect a relative excess or deficit of plasma water in relation to plasma sodium. There is no predictable relationship between plasma sodium concentration, extracellular fluid volume, and total body sodium content. Evaluation and management of dysnatremias rely on an understanding of key terminology, normal body fluid composition and distribution, and regulation of water and sodium balance, combined with a directed history and physical and appropriate laboratory tests. Enteral and parenteral nutrition regimens can be modified to help restore normal plasma sodium concentrations. Response to treatment requires close monitoring to avoid potential complications associated with rapid correction of hyponatremia and hypernatremia.
Transnasal Endoscopic Placement of Nasoenteric Feeding Tubes: Outcomes and Limitations in Non–Critically Ill Patients
Authors: Mahadeva Sanjiv , Malik Abdul , Hilmi Ida , Qua Choon‐Seng , Wong Choon‐Heng , Goh Khean‐Lee
Published: May 2008

Transnasal endoscopic placement of nasoenteric tubes (NETs) has been demonstrated to be useful in the critical care setting, with limited data on its role in non–critically ill patients. The authors collected data on consecutive patients from a non–critical care setting undergoing transnasal endoscopic NET placement. All NETs were endoscopically placed using a standard over‐the‐guidewire technique, and positions were confirmed with fluoroscopy. Patients were monitored until the removal of NETs or death. Twenty‐two patients (median age = 62.5 years, 36.4% female) were referred for postpyloric feeding, with main indications of persistent gastrocutaneous fistula (n = 6), gastroparesis or gastric outlet obstruction (n = 5), duodenal stenosis (n = 6), acute pancreatitis (n = 4), and gastroesophageal reflux after surgery (n = 1). Postpyloric placement of NET was achieved in 19 of 22 (86.3%) patients, with 36.8% tube positions in the jejunum, 47.4% in the distal duodenum, and 15.8% in the second part of the duodenum. NET placement was least successful in cases with duodenal stenosis. NETs remained in situ for a median of 24 days (range, 2‐94), with tube dislodgement (n = 3) and clogging (n = 5) as the main complications. NET feeding resulted in complete healing of gastrocutaneous fistulae in 5 of 6 patients and provision of total enteral nutrition in 3 of 4 cases of acute pancreatitis and 9 of 11 cases of gastroparesis or proximal duodenal obstruction. Transnasal endoscopy has a role in the placement of NET in non–critically ill patients requiring postpyloric feeding. However, there are some limitations, particularly in cases with altered duodenal anatomy.
Low-dose radiation risk extrapolation fallacy associated with the linear-no-threshold model
Authors: Scott Bobby R
Published: May 2008

Managing radiation risks typically involves establishing regulations that limit radiation exposure. The linear-no-threshold (LNT) dose—response model has been the traditional regulatory default assumption. According to the LNT model, for low a linear-energy-transfer (LET) radiation-induced stochastic effects (e.g., neoplastic transformation and cancer), the risk increases linearly without a threshold. Any radiation exposure is predicted to increase the number of cancer cases among a large population of people. Cancer risk extrapolation from high to low doses based on this model is widespread. Here, indirect evidence is provided that the excess cancer risk calculated at very low doses of low-LET radiation (e.g., around 1 mGy), based on extrapolating from high dose data for an irradiated human population using the LNT model, is likely a phantom excess risk. Indirect evidence is provided, suggesting that for brief exposures to low-LET radiation doses on the order of 1 mGy, that a decrease below the spontaneous level is many orders of magnitude more probable than for any increase in risk as would be predicted by extrapolating from high to low doses using the LNT model. Such a decrease is, however, not expected after exposure to high-LET alpha radiation. The risk reduction has been largely attributed to the induction of a protective apoptosis-mediated (PAM) process that selectively eliminates cells that contain genomic instability (e.g., mutant and neoplastically transformed cells). The PAM process appears to require a dose-rate-dependent stochastic threshold for activation whose minimum is estimated to possibly be as low as 0.01 mGy for X-rays and gamma rays. However, if the dose is too high (e.g., above 250mGy for brief exposure at a high rate to X-rays or gamma rays), the PAM process is not expected to be activated. For protracted exposure to X-rays or gamma rays, doses as high as 400 mGy (and possibly higher) may activate the PAM process.
Hormesis and disease resistance: activation of cellular stress response pathways
Authors: Mattson Mark P
Published: May 2008

The survival of all organisms depends upon their ability to overcome stressful conditions, an ability that involves adaptive changes in cells and molecules. Findings from studies of animal models and human populations suggest that hormesis (beneficial effects of low levels of stress) is an effective means of protecting against many different diseases including diabetes, cardiovascular disease, cancers and neurodegenerative disorders. Such stress resistance mechanisms can be bolstered by diverse environmental factors including exercise, dietary restriction, cognitive stimulation and exposure to low levels of toxins. Some commonly used vitamins and dietary supplements may also induce beneficial stress responses. Several interrelated cellular signaling molecules are involved in the process of hormesis. Examples include the gases oxygen, carbon monoxide and nitric oxide, the neurotransmitter glutamate, the calcium ion and tumor necrosis factor. In each case low levels of these signaling molecules are beneficial and protect against disease, whereas high levels can cause the dysfunction and/or death of cells. The cellular and molecular mechanisms of hormesis are being revealed and include activation of growth factor signaling pathways, protein chaperones, cell survival genes and enzymes called sirtuins. Knowledge of hormesis mechanisms is leading to novel approaches for preventing and treating a range of human diseases.
Unintentional poisoning by phosphine released from aluminum phosphide
Authors: Shadnia S , Mehrpour O , Abdollahi M
Published: May 2008

Aluminum phosphide as a releaser of phosphine gas is used as a grain preservative. In this case report, we describe an accidental severe poisoning in a 35-year-old woman, her 18-year-old daughter, and 6-year-old son caused by inhalation of phosphine gas released from 20 tablets of aluminum phosphide stored in 15 rice bags. The boy died 2 days after exposure before admission to hospital and any special treatment, but the others were admitted 48 h after exposure. They had signs and symptoms of severe toxicity, and their clinical course included metabolic acidosis, electrocardiographic changes, and hypotension. They were treated by intravenous administration of sodium bicarbonate, magnesium sulfate, and calcium gluconate. The patients were discharged after 3 days and followed up for 1 week after discharge. Rapid absorption of phosphine by inhalation, induction of hyperglycemia, and surviving of patients are interesting issues of this case report.
Concept of REACH and impact on evaluation of chemicals
Authors: Foth H , Hayes AW
Published: May 2008

Industrial chemicals have been in use for many decades and new products are regularly invented and introduced to the market. Also for decades, many different chemical laws have been introduced to regulate safe handling of chemicals in different use patterns. The patchwork of current regulation in the European Union is to be replaced by the new regulation on industrial chemical control, REACH. REACH stands for registration, evaluation, and authorization of chemicals. REACH entered force on June 1, 2007. REACH aims to overcome limitations in testing requirements of former regulation on industrial chemicals to enhance competitiveness and innovation with regard to manufacture safer substances and to promote the development of alternative testing methods. A main task of REACH is to address data gaps regarding the properties and uses of industrial chemicals. Producers, importers, and downstream users will have to compile and communicate standard information for all chemicals. Information sets to be prepared include safety data sheets (SDS), chemical safety reports (CSR), and chemical safety assessments (CSA). These are designed to guarantee adequate handling in the production chain, in transport and in use and to prevent the substances from being released to and distributed within the environment. Another important aim is to identify the most harmful chemicals and to set incentives to substitute them with safer alternatives. On one hand, REACH will have substantial impact on the basic understanding of the evaluation of chemicals. However, the toxicological sciences can also substantially influence the workability of REACH that supports the transformation of data to the information required to understand and manage acceptable and non acceptable risks in the use of industrial chemicals. The REACH regulation has been laid down in the main document and 17 Annexes of more than 849 pages. Even bigger technical guidance documents will follow and will inform about the rules for application and work out of dossiers. The following article gives a comprehensive overview on the concept of REACH to give deeper insight into this document. Members of the scientific community will have to define their own position as researchers, teachers, and experts to support the efforts to protect human health and the environment. The concept of REACH as well as new approaches to adapt standard testing regimes to foster a risk oriented approach in required work load to decrease animal based tests and to strengthen weight of evidence are explained in detail in this article.
Long-term exposure to gaseous formaldehyde promotes allergen-specific IgE-mediated immune responses in a murine model
Authors: Gu YH , Fujimiya Y , Kunugita N
Published: May 2008

It has long been questioned that whether exposure to formaldehyde in indoor environments may be a risk factor for developing allergen-specific IgE-mediated inflammatory responses, because there is limited clinical or experimental evidence that formaldehyde is involved in the cascade for IgE production. There is no known lower limit, below which there is no threat of serious allergic symptoms. The present study illustrates that the threshold limit of formaldehyde, 0.08 ppm (as defined by the World Health Organization), did not cause ovalbumin-specific IgE inflammatory immune responses, but higher than threshold concentrations of formaldehyde gas result in both enhanced allergen-specific IgE responses and NK (Natural Killer)-cell activity in peripheral blood cells in a murine model. Thus, formaldehyde gas may be involved in promoting allergic inflammatory effects in subjects primed with specific allergens by NK-cell activation. These results indicate that even threshold concentrations of formaldehyde gas may play a regulatory role for ‘systemic’ cell-mediated immune responses. The extensive use of adhesives for building materials has resulted in higher levels of indoor air pollutants. It is conceivable that increased time indoors may enhance pre-existing allergic symptoms by concomitant exposure to volatile organic compounds and formaldehyde. The affordable limit for formaldehyde might be much lower than currently established levels in indoor environments.
N,N-diethyl-2-[4-(phenylmethyl) phenoxy] ethanamine (DPPE; tesmilifene), a chemopotentiating agent with hormetic effects on DNA synthesis in vitro, may improve survival in patients with metastatic breast cancer
Authors: Brandes Lorne J
Published: May 2008

N,N-diethyl-2-[4-(phenylmethyl) phenoxy] ethanamine (DPPE; tesmilifene) is a novel anti-histaminic and chemopotentiating agent that has a hormetic effect on DNA synthesis in MCF (Michigan Cancer Foundation)-7 human breast cancer cells in vitro and stimulates the growth of experimental tumors in rodents. In a prospectively randomized phase three trial (NCIC MA.19), 152 patients who were co-administered DPPE and doxorubicin survived 50% longer ( P < 0.03) than 153 patients who were administered the same dose and schedule of doxorubicin alone. At clinically relevant in vitro concentrations that do not inhibit the P-glycoprotein (P-gp) pump, DPPE selectively sensitizes the cancer cells that express the multiple drug resistance phenotype, making them more susceptible to the cytotoxic effects of chemotherapeutic agents, including anthracyclines and taxanes. Based on its previously demonstrated interaction with histamine at CYP3A4, a P450 that metabolizes arachidonic acid, and its induction of high levels of prostacyclin in the gut of rodents, modulation by DPPE of the intracellular concentration of arachidonate products, such as hydroxyeicosatetraeinoic acids, implicated in increased cancer cell proliferation and metastasis, is postulated.
Should we explore the clinical utility of hormesis?
Authors: Jonas Wayne B , Ives John A
Published: May 2008

The idea that low-dose adaptive effects as described in hormesis can be used clinically has been discussed for hundreds if not thousands of years. Paracelsus famous adage that `the dose makes the poison' and the common folk saying that one can be cured by `the hair of the dog that bit you' speak to this idea. So why has so little research been done on the possible clinical utility of hormesis? What areas of clinical hormesis seem to be the most promising to explore? This article examines these concepts and proposes some initial areas or research where the possible utility of hormeiss might be investigated.
Experimental Identification of the Nonlinear Parameters of an Industrial Translational Guide for Machine Performance Evaluation
Authors: Dhupia Jaspreet S. , Ulsoy A. Galip , Katz Reuven , Powalka Bartosz
Published: May 2008

Prediction of machine dynamics at the design stage is a challenge due to lack of adequate methods for identifying and handling the nonlinearities in the machine joints, which appear as the nonlinear restoring force function of relative displacement and relative velocity across the joint. This paper discusses identification of such a nonlinear restoring force function for an industrial translational guide for use with the Nonlinear Receptance Coupling Approach (NLRCA) to evaluate machine dynamic characteristics. Translational guides are among the most commonly used joints in machine tools. Both parametric and nonparametric techniques have been employed to identify the nonlinearities. A novel parametric model based on Hertzian contact mechanics has been derived for the translational guide. A nonparametric method based on two-dimensional Chebyshev polynomials is also used. The models derived from the two techniques, i.e., parametric and nonparametric, are fitted to the experimental data derived from static and dynamic tests to get the restoring force as a function of relative displacement and relative velocity across the joint. The nonlinear representation obtained from both techniques is later converted into the describing function representation which is needed for evaluation of machine dynamic characteristics using the NLRCA. The describing function representations obtained from the two approaches are compared. The design of experiments for evaluating the nonlinearities in such industrial machine tool joints is a challenge, requiring careful alignment and calibration, because they are typically very stiff. This constrains the dynamic experiments to be carried out at high frequencies (e.g. 2000—7000 Hz) where the experimental readings are very sensitive to errors in geometry and calibration.
Damping by Parametric Stiffness Excitation: Resonance and Anti-Resonance
Authors: Dohnal F.
Published: May 2008

Investigations are presented into the stability of vibration suppression employing variable-stiffness actuators. Systems with an arbitrary number of degrees of freedom are considered, and are subject to both parametric excitation and self-excitation. Analytical conditions of stability and instability are derived by applying a singular perturbation technique. These conditions enable a stability classification that naturally leads to the description parametric anti-resonance. The influence of the symmetry property of the parametric excitation matrix on the location of the parametric anti-resonance is discussed. Additionally, the influence of parametric resonance and anti-resonance on the eigenvalues corresponding to the slow motion of a generic system are analysed. A geometric interpretation is presented, enabling deeper insight into the mechanism of vibration suppression, and leading to the interpretation of coupling modes using parametric anti-resonance and amplification of system damping. The basic results obtained can be used for design of a control strategy for variable-stiffness actuators.
Scalable and Invertible PMNN Model for MagnetoRheological Fluid Dampers
Authors: Cao M. , Wang K.W. , Lee Kwang Y.
Published: May 2008

To advance the state of the art of physical-principle-enhanced hybrid artificial neural network (ANN) modeling, network configurations with parallel modules (PMNN) reflecting the structural information of the physical principles have been developed (Cao, 2001). In this paper, the PMNN configuration is applied to develop a scalable and invertible dynamic magneto-rheological (MR) fluid damper model. To advance the state of the art and address issues of the current ANN-based MR damper models found in the open literature, two ANN-based MR damper models are developed in this study. The first one is a conventional first-principle-enhanced hybrid neural network model (defined as the baseline model in the current study) that improves upon the previous ANN-based MR damper models by introducing feedback loops to represent the dynamic behaviors of the MR damper. A PMNN-based MR damper model is then derived to further improve the control-input-output scalability and realize the invertible model concept. “Input-output scalability” refers to the model's capability to accurately estimate the system response with input profiles significantly different from the training data. “Invertible model” means that the resultant forward model can be directly transformed into an inverse model through a simple algebraic operation. The network training/testing results indicate that while both models provide satisfactory performance, the PMNN model outperforms the baseline model by showing superior control-input-output scalability. The candidacy of PMNN as a control-oriented actuator modeling tool is further strengthened by the fact that it is invertible, in other words, the inverse model with desired force as input and the control signal—voltage as output can be easily established by algebraically manipulating the forward model. This study indicates that PMNN, as a scalable and invertible dynamic modeling tool, is feasible for developing system-design-oriented models of vibration control purposes.
Principles of Servant-Leadership in Community Health Nursing
Authors: Sturm Bonnie A.
Published: May 2008

This article discusses the outcomes of a secondary analysis of ethnographic research data, focusing specifically on management issues and behaviors which can help the reader to visualize evidence-based examples of servant-leadership, a transformational leadership model that seeks to empower members of an organization to act as both servants and leaders within a work environment of mutual respect, trust, and collaboration. Participants included nurses, supervisors, administrators, and others observed and interviewed in the agency and nurses accompanied on home visits. Analysis revealed leadership behaviors and issues which are clarified through example(s) and sorted into three thematic categories: respect and valuing of one as a unique individual, affirmation of professional judgment and fair treatment regarding workload, and collaboration with supervisors and administrators in a spirit of willingness. A servant-leadership model can support personal and professional growth, empowering nurses to play a leadership role and thereby increasing nurse collaboration, satisfaction, and retention.
Molecular profiling of LGL leukemia reveals role of sphingolipid signaling in survival of cytotoxic lymphocytes
Authors: Shah Mithun Vinod , Zhang Ranran , Irby Rosalyn , Kothapalli Ravi , Liu Xin , Arrington Ty , Frank Bryan , Lee Norman H. , Loughran Thomas P.
Published: May 2008

T-cell large granular lymphocyte (LGL) leukemia is characterized by clonal expansion of CD3+CD8+ cells. Leukemic LGLs correspond to terminally differentiated effector-memory cytotoxic T lymphocytes (CTLs) that escape Fas-mediated activation-induced cell death (AICD) in vivo. The gene expression signature of peripheral blood mononuclear cells from 30 LGL leukemia patients showed profound dysregulation of expression of apoptotic genes and suggested uncoupling of activation and apoptotic pathways as a mechanism for failure of AICD in leukemic LGLs. Pathway-based microarray analysis indicated that balance of proapoptotic and antiapoptotic sphingolipid-mediated signaling was deregulated in leukemic LGLs. We further investigated sphingolipid pathways and found that acid ceramidase was constitutively overexpressed in leukemic LGLs and that its inhibition induced apoptosis of leukemic LGLs. We also showed that S1P5 is the predominant S1P receptor in leukemic LGLs, whereas S1P1 is down-regulated. FTY720, a functional antagonist of S1P-mediated signaling, induced apoptosis in leukemic LGLs and also sensitized leukemic LGLs to Fas-mediated death. Collectively, these results show a role for sphingolipid-mediated signaling as a mechanism for long-term survival of CTLs. Therapeutic targeting of this pathway, such as use of FTY720, may have efficacy in LGL leukemia.
Improved microarray gene expression profiling of virus-infected cells after removal of viral RNA
Authors: Raaben Matthijs , Whitley Penn , Bouwmeester Diane , Setterquist Robert A , Rottier Peter JM , de Haan Cornelis AM
Published: May 2008

Background

Sensitivity and accuracy are key points when using microarrays to detect alterations in gene expression under different conditions. Critical to the acquisition of reliable results is the preparation of the RNA. In the field of virology, when analyzing the host cell's reaction to infection, the often high representation of viral RNA (vRNA) within total RNA preparations from infected cells is likely to interfere with microarray analysis. Yet, this effect has not been investigated despite the many reports that describe gene expression profiling of virus-infected cells using microarrays.

Results

In this study we used coronaviruses as a model to show that vRNA indeed interferes with microarray analysis, decreasing both sensitivity and accuracy. We also demonstrate that the removal of vRNA from total RNA samples, by means of virus-specific oligonucleotide capturing, significantly reduced the number of false-positive hits and increased the sensitivity of the method as tested on different array platforms.

Conclusion

We therefore recommend the specific removal of vRNA, or of any other abundant 'contaminating' RNAs, from total RNA samples to improve the quality and reliability of microarray analyses.
Suspension culture combined with chemotherapeutic agents for sorting of breast cancer stem cells
Authors: Li Hai-zhi , Yi Tong-bo , Wu Zheng-yan
Published: May 2008

Background

Cancer stem cell (CSC) hypothesis has not been well demonstrated by the lack of the most convincing evidence concerning a single cell capable of giving rise to a tumor. The scarcity in quantity and improper approaches for isolation and purification of CSCs have become the major obstacles for great development in CSCs. Here we adopted suspension culture combined with anticancer regimens as a strategy for screening breast cancer stem cells (BrCSCs). BrCSCs could survive and be highly enriched in non-adherent suspension culture while chemotherapeutic agents could destroy most rapidly dividing cancer cells and spare relatively quiescent BrCSCs.

Methods

TM40D murine breast cancer cells were cultured in serum-free medium. The expression of CD44+CD24- was measured by flow cytometry. Cells of passage 10 were treated in combination with anticancer agents pacilitaxel and epirubicin at different peak plasma concentrations for 24 hours, and then maintained under suspension culture. The rate of apoptosis was examined by flow cytometry with Annexin-V fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining method. Selected cells in different amounts were injected subcutaneously into BALB/C mice to observe tumor formation.

Results

Cells of passage 10 in suspension culture had the highest percentage of CD44+CD24- (about 77 percent). A single tumor cell in 0.35 PPC could generate tumors in 3 of 20 BALB/C mice.

Conclusion

Suspension culture combined with anticancer regimens provides an effective means of isolating, culturing and purifying BrCSCs.
Isolation and characterization of cidofovir resistant vaccinia viruses
Authors: Becker Marie N , Obraztsova Maria , Kern Earl R , Quenelle Debra C , Keith Kathy A , Prichard Mark N , Luo Ming , Moyer Richard W
Published: May 2008

Background

The emergence of drug resistant viruses, together with the possibility of increased virulence, is an important concern in the development of new antiviral compounds. Cidofovir (CDV) is a phosphonate nucleotide that is approved for use against cytomegalovirus retinitis and for the emergency treatment of smallpox or complications following vaccination. One mode of action for CDV has been demonstrated to be the inhibition of the viral DNA polymerase.

Results

We have isolated several CDV resistant (CDVR) vaccinia viruses through a one step process, two of which have unique single mutations within the DNA polymerase. An additional resistant virus isolate provides evidence of a second site mutation within the genome involved in CDV resistance. The CDVR viruses were 3–7 fold more resistant to the drug than the parental viruses. The virulence of the CDVR viruses was tested in mice inoculated intranasally and all were found to be attenuated.

Conclusion

Resistance to CDV in vaccinia virus can be conferred individually by at least two different mutations within the DNA polymerase gene. Additional genes may be involved. This one step approach for isolating resistant viruses without serial passage and in the presence of low doses of drug minimizes unintended secondary mutations and is applicable to other potential antiviral agents.
Leukocyte numbers and function in subjects eating n-3 enriched foods: selective depression of natural killer cell levels
Authors: Mukaro Violet R , Costabile Maurizio , Murphy Karen J , Hii Charles S , Howe Peter R , Ferrante Antonio
Published: May 2008

Introduction

While consumption of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) has been recommended for those at risk of inflammatory disease such as rheumatoid arthritis, the mechanism of their anti-inflammatory effect remains to be clearly defined, particularly in relation to the dose and type of n-3 LCPUFA. The objective of this study was to determine whether varying the levels of n-3 LCPUFA in erythrocyte membrane lipids, following dietary supplementation, is associated with altered numbers and function of circulating leukocytes conducive to protection against inflammation.

Methods

In a double-blind and placebo-controlled study, 44 healthy subjects aged 23 to 63 years consumed either standard or n-3 LCPUFA-enriched versions of typical processed foods, the latter allowing a target daily consumption of 1 gram n-3 LCPUFA. After six months, peripheral blood leukocyte and subpopulation proportions and numbers were assessed by flow cytometry. Leukocytes were also examined for lymphoproliferation and cytokine production, neutrophil chemotaxis, chemokinesis, bactericidal, adherence and iodination activity. Erythrocytes were analyzed for fatty-acid content.

Results

Erythrocyte n-3 LCPUFA levels were higher and absolute leukocyte and lymphocyte numbers were lower in subjects consuming n-3 enriched foods than in controls. There were no changes in the number of neutrophils, monocytes, T cells (CD3+), T-cell subsets (CD4+, CD8+) and B cells (CD19+). However, natural killer (NK) (CD3-CD16+CD56+) cell numbers were lower in n-3 supplemented subjects than in controls and were inversely related to the amount of eicosapentaenoic acid or docosahexaenoic acid in erythrocytes. No significant correlations were found with respect to lymphocyte lymphoproliferation and production of IFN-γ and IL-2, but lymphotoxin production was higher with greater n-3 LCPUFA membrane content. Similarly, neutrophil chemotaxis, chemokinesis, bactericidal activity and adherence did not vary with changes in erythrocyte n-3 LCPUFA levels, but the iodination reaction was reduced with higher n-3 LCPUFA content.

Conclusion

The data show that regular long-term consumption of n-3 enriched foods leads to lower numbers of NK cells and neutrophil iodination activity but higher lymphotoxin production by lymphocytes. These changes are consistent with decreased inflammatory reaction and tissue damage seen in patients with inflammatory disorders receiving n-3 LCPUFA supplementation.
Estrogen, not intrinsic aging, is the major regulator of delayed human wound healing in the elderly
Authors: Hardman Matthew J , Ashcroft Gillian S
Published: May 2008

Background

Multiple processes have been implicated in age-related delayed healing, including altered gene expression, intrinsic cellular changes, and changes in extracellular milieu (including hormones). To date, little attempt has been made to assess the relative contribution of each of these processes to a human aging phenomenon. The objective of this study is to determine the contribution of estrogen versus aging in age-associated delayed human wound healing.

Results

Using an Affymetrix microarray-based approach we show that the differences in gene expression between male elderly and young human wounds are almost exclusively estrogen regulated. Expression of 78 probe sets was significantly decreased and 10 probe sets increased in wounds from elderly subjects (with a fold change greater than 7). A total of 83% of down-regulated probe sets and 80% of up-regulated probe sets were estrogen-regulated. Differentially regulated genes were validated at the level of gene and protein expression, with genes identified as estrogen-regulated in human confirmed as estrogen-dependent in young estrogen depleted mice in vivo. Moreover, direct estrogen regulation is demonstrated for three array-identified genes, Sele, Lypd3 and Arg1, in mouse cells in vitro.

Conclusion

These findings have clear implications for our understanding of age-associated cellular changes in the context of wound healing, the latter acting as a paradigm for other age-related repair and maintenance processes, and suggest estrogen has a more profound influence on aging than previously thought.
Costimulatory effects of IL-1 on the expansion/differentiation of CD4+CD25+Foxp3+ and CD4+CD25+Foxp3– T cells
Authors: Brinster Carine , Shevach Ethan M
Published: May 2008

CD4+CD25+forkhead box p3 (Foxp3)+ regulatory T cells (Treg) control peripheral tolerance. Although Treg are anergic when stimulated through the TCR, mature bone marrow-derived, but not splenic, dendritic cells (DC) can induce their proliferation after TCR stimulation in the absence of IL-2. One possibility is that the DC produce proinflammatory cytokines such as IL-1 or IL-6 that function as growth factors for Treg. We have analyzed the costimulatory effects of IL-1 on the expansion of Foxp3+ Treg in vitro. When CD4+CD25+ T cells were cultured in the presence of splenic DC and IL-1, marked expansion of the Foxp3+ T cells was observed. The effects of IL-1 were mediated on CD4+CD25+Foxp3– T cells present in the starting population rather than on the DC or on the CD4+CD25+Foxp3+ T cells. In contrast, stimulation of CD4+CD25+ T cells with plate-bound anti-CD3 and IL-1 in the absence of DC resulted in the outgrowth of a CD4+CD25+Foxp3– T cell population composed of NKT cells and non-NKT, IL-17-producing cells. Foxp3+ Treg purified from mice expressing the reporter gene enhanced GFP in the Foxp3 locus failed to proliferate when costimulated with IL-1. These findings have important implications for the design of protocols for the expansion of CD4+CD25+ T cells for cellular biotherapy.
Immunostaining evidence for PI(4,5)P2 localization at the leading edge of chemoattractant-stimulated HL-60 cells
Authors: Sharma Ved P , DesMarais Vera , Sumners Colin , Shaw Gerry , Narang Atul
Published: May 2008

It is well known that in fMLP-stimulated neutrophils, phosphatidyl inositol 3,4,5-trisphosphate [PI(3,4,5)P3] localizes at the leading edge of the cells. However, no effort has been made to study the PI 4,5-bisphosphate [PI(4,5)P2] distribution in these cells. In fact, it has been suggested that PI(4,5)P2 is unlikely to localize, as its basal level is orders of magnitude higher than that of PI(3,4,5)P3. We developed an optimized immunostaining protocol for studying the endogenous distribution of PI(4,5)P2 in neutrophil-like HL-60 cells. We show that PI(4,5)P2 localizes sharply at the leading edge with an intensity gradient similar to that for PI(3,4,5)P3. The enzymes for the production of PI(4,5)P2, namely, PI5KIα and PI5KIγ, were also found to localize at the leading edge, further supporting our finding that PI(4,5)P2 localizes at the leading edge. These results imply that complementary regulation of PI3K and phosphate and tensin homolog (PTEN) is not the sole or dominant mechanism of PI(3,4,5)P3 polarization in HL-60 cells.
Islet Amyloid in Type 2 Diabetes, and the Toxic Oligomer Hypothesis
Authors: Haataja Leena , Gurlo Tatyana , Huang Chang J. , Butler Peter C.
Published: May 2008

Type 2 diabetes (T2DM) is characterized by insulin resistance, defective insulin secretion, loss of β-cell mass with increased β-cell apoptosis and islet amyloid. The islet amyloid is derived from islet amyloid polypeptide (IAPP, amylin), a protein coexpressed and cosecreted with insulin by pancreatic β-cells. In common with other amyloidogenic proteins, IAPP has the propensity to form membrane permeant toxic oligomers. Accumulating evidence suggests that these toxic oligomers, rather than the extracellular amyloid form of these proteins, are responsible for loss of neurons in neurodegenerative diseases. In this review we discuss emerging evidence to suggest that formation of intracellular IAPP oligomers may contribute to β-cell loss in T2DM. The accumulated evidence permits the amyloid hypothesis originally developed for neurodegenerative diseases to be reformulated as the toxic oligomer hypothesis. However, as in neurodegenerative diseases, it remains unclear exactly why amyloidogenic proteins form oligomers in vivo, what their exact structure is, and to what extent these oligomers play a primary or secondary role in the cytotoxicity in what are now often called unfolded protein diseases.
Cerebrospinal Fluid Dehydroepiandrosterone Levels Are Correlated with Brain Dehydroepiandrosterone Levels, Elevated in Alzheimer’s Disease, and Related to Neuropathological Disease Stage
Authors: Naylor Jennifer C. , Hulette Christine M. , Steffens David C. , Shampine Lawrence J. , Ervin John F. , Payne Victoria M. , Massing Mark W. , Kilts Jason D. , Strauss Jennifer L. , Calhoun Patrick S. , Calnaido Rohana P. , Blazer Daniel G. , Lieberman Jeffrey A. , Madison Roger D. , Marx Christine E.
Published: May 2008

Objective: It is currently unknown whether cerebrospinal fluid (CSF) neurosteroid levels are related to brain neurosteroid levels in humans. CSF and brain dehydroepiandrosterone (DHEA) levels are elevated in patients with Alzheimer’s disease (AD), but it is unclear whether CSF DHEA levels are correlated with brain DHEA levels within the same subject cohort. We therefore determined DHEA and pregnenolone levels in AD patients (n = 25) and cognitively intact control subjects (n = 16) in both CSF and temporal cortex.

Design: DHEA and pregnenolone levels were determined by gas chromatography/mass spectrometry preceded by HPLC. Frozen CSF and temporal cortex specimens were provided by the Alzheimer’s Disease Research Center at Duke University Medical Center. Data were analyzed by Mann-Whitney U test statistic and Spearman correlational analyses.

Results: CSF DHEA levels are positively correlated with temporal cortex DHEA levels (r = 0.59, P < 0.0001) and neuropathological disease stage (Braak and Braak) (r = 0.42, P = 0.007). CSF pregnenolone levels are also positively correlated with temporal cortex pregnenolone levels (r = 0.57, P < 0.0001) and tend to be correlated with neuropathological disease stage (Braak) (r = 0.30, P = 0.06). CSF DHEA levels are elevated (P = 0.032), and pregnenolone levels tend to be elevated (P = 0.10) in patients with AD, compared with cognitively intact control subjects.

Conclusions: These findings indicate that CSF DHEA and pregnenolone levels are correlated with temporal cortex brain levels of these neurosteroids and that CSF DHEA is elevated in AD and related to neuropathological disease stage. Neurosteroids may thus be relevant to the pathophysiology of AD.