bluuebunny/crossref_metadata_2025 huggingface dataset:
The tau Mutation in the Syrian Hamster Differentially Reprograms the Circadian Clock in the SCN and Peripheral Tissues
Authors: Dey J. , Carr A.-J. F. , Cagampang F. R. A. , Semikhodskii A. S. , Loudon A. S. I. , Hastings M. H. , Maywood E. S.
Published: April 2005

The hypothalamic suprachiasmatic nuclei (SCN), the principal circadian oscillator in mammals, are synchronized to the solar day by the light-dark cycle, and in turn, they coordinate circadian oscillations in peripheral tissues. The tau mutation in the Syrian hamster is caused by a point mutation leading to a deficiency in the ability of Casein Kinase 1ε to phosphorylate its targets, including circadian PER proteins. How this accelerates circadian period in neural tissues is not known, nor is its impact on peripheral circadian oscillators established. We show that this mutation has no effect on per mRNA expression nor the nuclear accumulation of PER proteins in the SCN. It does, however, accelerate the clearance of PER proteins from the nucleus to an extent sufficient to explain the shortened circadian period of behavioral rhythms. The mutation also has novel, unanticipated consequences for circadian timing in the periphery, including tissue-specific phase advances and/or reduced amplitude of circadian gene expression. The results suggest that the tau mutation accelerates a specific phase, during mid-late subjective night of the SCN circadian feedback loop, rather than cause a global compression of the entire cycle. This reprogrammed output from the clock is associated with peripheral desynchrony, which in turn could account for impaired growth and metabolic efficiency of the mutant.
Intrinsic Period and Light Intensity Determine the Phase Relationship between Melatonin and Sleep in Humans
Authors: Wright Kenneth P. , Gronfier Claude , Duffy Jeanne F. , Czeisler Charles A.
Published: April 2005

The internal circadian clock and sleep-wake homeostasis regulate the timing of human brain function, physiology, and behavior so that wakefulness and its associated functions are optimal during the solar day and that sleep and its related functions are optimal at night. The maintenance of a normal phase relationship between the internal circadian clock, sleep-wake homeostasis, and the light-dark cycle is crucial for optimal neurobehavioral and physiological function. Here, the authors show that the phase relationship between these factors—the phase angle of entrainment (ψ)—is strongly determined by the intrinsic period (τ) of the master circadian clock and the strength of the circadian synchronizer. Melatonin was used as a marker of internal biological time, and circadian period was estimated during a forced desynchrony protocol. The authors observed relationships between the phase angle of entrainment and intrinsic period after exposure to scheduled habitual wakefulness-sleep light-dark cycle conditions inside and outside of the laboratory. Individuals with shorter circadian periods initiated sleep and awakened at a later biological time than did individuals with longer circadian periods. The authors also observed that light exposure history influenced the phase angle of entrainment such that phase angle was shorter following exposure to a moderate bright light (~450 lux)–dark/wakefulness-sleep schedule for 5 days than exposure to the equivalent of an indoor daytime light (~150 lux)–dark/wakefulness-sleep schedule for 2 days. These findings demonstrate that neurobiological and environmental factors interact to regulate the phase angle of entrainment in humans. This finding has important implications for understanding physiological organization by the brain’s master circadian clock and may have implications for understanding mechanisms underlying circadian sleep disorders.
The Internationalisation of Higher Education: A Paradigm for Global Citizenry
Authors: Gacel-Ávila Jocelyne
Published: April 2005

This article presents internationalisation as a new educational vision able to provide global society with an education that meets current needs and that can respond efficiently to contemporary demands and challenges, which are characterized by globalisation, interdependence, and multiculturalism.
A Hermeneutical Study of Older Korean Graduate Students’ Experiences in American Higher Education: From Confucianism to Western Educational Values
Authors: Seo Seonjin , Koro-Ljungberg Mirka
Published: April 2005

In this hermeneutical study, the authors focus on understanding the experiences of older Korean students who have come to the United States to pursue academic degrees at American universities. The purpose of this study is to describe the critical events related to their adjustment processes as well as to address some of the specific concerns of the students who returned to higher education after a long professional career in their home countries. In particular, the authors find it important to describe some of the adjustment problems from the Korean cultural perspective relating to Confucianism, loyalty, and respect. The authors conclude by arguing that without situational cultural understandings or without respect for the cultural historicity of international students, the quality of the educational experience in higher education will not be promoted.
On Cooperation and Competition: A Comparative Analysis of National Policies for Internationalisation of Higher Education in Seven Western European Countries
Authors: Luijten-Lub Anneke , Van der Wende Marijk , Huisman Jeroen
Published: April 2005

The focus of this article is on a comparison of the national policies for internationalisation in seven Western European countries (Austria, Germany, Greece, the Netherlands, Norway, Portugal, and the United Kingdom). In this comparison, it will be shown that the trend suggested in previous research of increasing economical rationales for internationalisation and mainstreaming of higher education have persisted during the past few years. In addition, the approach to internationalization in the seven countries has broadened and is no longer mainly about student and staff mobility. Finally, the article shows that changes in the higher education policy context, including international and global developments, have brought about reforms in the higher education systems of the countries; these developments, however, have no uniform impact on the higher education policy and systems.
A Community-Based Depression Prevention Intervention With Low-Income Single Mothers
Authors: Peden Ann R. , Rayens Mary Kay , Hall Lynne A.
Published: April 2005

BACKGROUND: There is growing support that cognitive-behavioral interventions may prevent the onset of clinical depression in at-risk individuals. OBJECTIVES: This article describes the long-term effects of a cognitive-behavioral group intervention in reducing depressive symptoms, negative thinking, and chronic stressors in low-income single mothers at risk for clinical depression. STUDY DESIGN: One hundred thirty-six women were randomly assigned to either an experimental or no-treatment control group. The experimental group participated in a 6-hour cognitive-behavioral group intervention targeting identification and reduction of negative thinking. Data were collected on depressive symptoms, negative thinking, and chronic stressors at 1, 6, and 12 months postintervention. RESULTS: The women in the intervention group experienced a greater reduction in depressive symptoms, negative thinking, and the perception of chronic stressors. These positive effects continued over a 12-month period. CONCLUSIONS: Negative thinking can be reduced using thought stopping and affirmations. These interventions are also cost-effective and easy to administer.
The Lived Experience of Choosing Bariatric Surgery to Lose Weight
Authors: Wysoker Amy
Published: April 2005

BACKGROUND: Surgical treatment for morbid obesity is becoming an increasingly sought out intervention for weight loss. Bariatric surgery is a life-changing procedure that requires a long-term commitment from the individual. OBJECTIVE: The purpose of this research was to explore issues relating to having a surgical procedure performed to lose weight. STUDY DESIGN: A phenomenological study was conducted. The sample included five females and three males who had undergone surgery to reduce weight at least 1 year prior to the study participation. RESULTS: Qualitative data analysis revealed the following four themes: last resort, surgery provides structure, reality setsin, and positive about the decision to have the surgery. CONCLUSION: Understanding these themes offers much needed information for health professionals when treating the morbidly obese person. Psychiatric nurses and psychiatric advanced practice nurses can offer a holistic approach and implement programs that incorporate study findings into individual treatment plans. Nurse psychotherapists can explore these findings in therapy sessions and focus on the impact they have on the person’s goals to maintain weight loss.
A Comparison of On-Site and Telepsychiatry Supervision
Authors: Heckner Coleen , Giard April
Published: April 2005

Telemedicine has been used in rural settings for more than 25 years to provide services for patients and educational opportunities for practitioners. There is little documentation in the literature about using telepsychiatry for supervising psychiatric nurse practitioners. This article discusses the supervision experiences of two groups of psychiatric nurse practitioners. One group of four nurses met weekly with a psychiatrist on-site. The other group of four nurses, working in three different clinical locations in Maine, met via a two-way interactive television connection with a psychiatrist based in Boston, Massachusetts.
The Burden of Disease in Those With Serious Mental and Physical Illnesses
Authors: Kennedy Carol , Salsberry Pamela , Nickel Jennie , Hunt Chantal , Chipps Esther
Published: April 2005

BACKGROUND: Clients with severe mental illness are known to have higher morbidity than the general population, but little is known about their perception of disease burden. OBJECTIVE: This study examined the disease burden in a cohort of community-dwelling persons diagnosed with severe mental illness. STUDY DESIGN: This was a descriptive study that included: interviews, measures of blood pressure, height and weight, and chart audits from 109 volunteers. RESULTS: Mean scores on the Medical Outcomes Study Short Form–12 (MOS SF-12) were compared by gender and five chronic illnesses. The participants had lower scores on the physical (PCS) and mental (MCS) health components of the MOS SF-12 than the general population. Participants with depression, hypertension, arthritis, diabetes, and chronic lung disease scored lower than the general population on the PCS and MCS. CONCLUSION: This study suggests that clients with severe mental illness and physical health problems experience a greater disease burden than do their counterparts in the general population.
Treating Postpartum Depression in Immigrant Muslim Women
Authors: Fonte Julia , Horton-Deutsch Sara
Published: April 2005

Distinct challenges face psychiatric-mental health nurses who treat a growing population of ethnically, racially, and culturally diverse patients. Nurses must be educated about the cultural beliefs and health practices within specific patient populations to provide comprehensive health care to patients. The purpose of this article is to educate nurses on postpartum depression among immigrant Muslim women.
Intelligent automation of electron beam physical vapour deposition
Authors: Cho S. , Lewis S. , Prabhu V. , Fuke I.
Published: April 2005

The present paper presents an intelligent automation of the electron beam physical vapour deposition (EBPVD) process to achieve high quality and cost efficient coatings for low volume part production, using realtime feedback control. A computational model of EBPVD for predicting coating thickness is used with an optimisation heuristic for reducing coating thickness variance and feedback control approaches for substrate temperature control and melt pool control. The computational model can be readily generated using a standard computer aided design (CAD) model of the workpiece, which makes the method applicable to workpieces with complex three-dimensional geometry. Based on this model, an optimisation heuristic for the EBPVD process is developed to control workpiece motion systematically with the objective of reducing coating thickness variance, i.e. providing a uniform coating. These computational developments are illustrated using a simulation of a turbine blade coating in which the coating thickness variance is reduced significantly. Process level intelligence is incorporated using realtime feedback control for substrate temperature and melt pool control using an open architecture control system. Results using thermocouple based temperature control and realtime vision for melt pool control are presented. Video images of the melt pool are analysed on a block by block basis, using a technique to identify critical regions of the melt pool. Simulation results demonstrate the feasibility of automating the electron gun beam steering sequence. The proposed methods offer the prospect of eliminating dedicated tooling/fixtures and improving the cost effectiveness of the process, especially for low volume production.
Influence of laser beam guiding and overlapping on residual stress in remelting process
Authors: Grum J. , Šturm R.
Published: April 2005

The laser remelting process is a very promising hardening method for ferrous and non-ferrous alloys which do not show a homogeneous microstructural state after being heat treated in a traditional way. Consequently, the alloys concerned do not achieve the required hardness of the surface layer and do not provide the required wear resistance. The present paper deals with residual stress and strain changes in thin flat specimens of nodular cast iron 500-7 in the laser remelting process. In the process of gradual remelting of the specimen surface, i.e. during its heating and cooling, volume changes in the specimen occur due to thermal and microstructural changes. To find out more about volume changes in the thin surface layer of specimens, the latter were monitored by strain measurement at the lower side of the specimens during the remelting process and by residual stress measurement in the thin surface layer after the remelting process. The strain was measured using a resistance rosette, placed on the opposite side of the remelted layer, and the temperature was measured in the same place simultaneously. In laser remelting of a workpiece, such remelting conditions should ensure that a uniform thickness of the modified layer is obtained, in spite of several laser beam passages across the workpiece surface. Owing to the multiple passage of the laser beam across the workpiece surface, the state of internal stress in the workpiece changes and, consequently, undesired strain may occur. Such strain may result in greater consumption of material and additional machining which, in turn, may result in higher cost of the machined parts. The results obtained confirmed that on the basis of knowing the strain occurring during the remelting process and the residual stress, the process could be successfully optimised. On the basis of knowing the strains occurring during the remelting process and the residual stress, optimal laser surface remelting conditions were chosen, while the method of guiding the laser beam over the surface of the flat samples and the degree of overlap were varied.
Residual stresses and adhesion of thermal spray coatings
Authors: Araujo P. , Chicot D. , Staia M. , Lesage J.
Published: April 2005

Residual stresses generated in coatings during thermal spraying could have very different inside intensity and distribution, depending on the materials and processing conditions. As it is recognised that residual stresses play a major role in the adhesion of coatings, it is necessaryto evaluate precisely their influence. It is not possible to conduct these measurements directly, and no indication on how the stresses should be taken into account has been reported in the literature. Moreover, depending on the test used to evaluate adhesion, different volumes of the coatingcan participate in the delamination process. In order to take into account these observations, it is proposed to define two stress parameters related either to the stresses in the coating or to the stresses at the interfacial zone. In these conditions, it is possible to explain the variationin adhesion as a function of the coating thickness, i.e. to explain the maximum value obtained for the bonding strength deduced from tensile tests and the monotonic increase in adhesion toughness deduced from interfacial indentation tests.
Role of gold in high temperature oxidation of titanium alloy
Authors: Zhang Z.X. , Dong H. , Bell T.
Published: April 2005

Oxidation of titanium and its alloys at a high temperature for a short time was carried out with gold and platinum predeposition. Preliminary results show gold can improve the quality of the oxide and the bond strength of the metal/oxide. Gold predeposition leads to a thicker oxide layer and more absorption of oxygen. Further investigations show that the existence of the thin gold layer is beneficial for the outward diffusion of titanium during oxidation at 800°C and 850°C.
Adhesion prediction on metal thermal spray coatings
Authors: Chis M. C. , Cojocaru M. O.
Published: April 2005

Bonding prediction (presence or absence of adhesion) of metal thermal spray coatings is of theoretical and practical interest. The present paper introduces a simple method for estimating the adhesion performance of metal thermal spray coatings. To improve the conditions expected in the case of poor adhesion, the proposed method can also provide and anticipate suitable types of metal thermal spray coatings to overcome the problem. The expansion coefficient is inventively used as a quality indication for bonding performance of metal thermal spray coatings.
Thermal oxidation treatment of iron aluminide for improved tribological properties
Authors: Xia J.
Published: April 2005

A major setback in the industrial applications of high strength to weight ratio iron aluminides is their poor tribological properties under dynamically loaded conditions. A surface modification technique, namely thermal oxidation (TO) treatment, was developed in the present study toimprove the load bearing capacity and tribological properties of a B2 structured iron aluminide (Fe40Al). The treatment was performed at 1000°C for various time from 10 to 150 h. The composition, microstructure and mechanical properties of the TO treated surfaces were characterised bya number of analytical techniques. The load bearing capacities and antiscuffing properties of the TO treated samples were evaluated by an Amsler block on wheel machine. The tribological properties of the TO treated and untreated iron aluminide were investigated using a pin on disc wear tester.It was shown that a hard and dense α-Al2O3 layer is formed on the iron aluminide surface after TO treatment, which has an increase in surface hardness from 5.5 GPa to 26.3 GPa and in elastic modulus from 200 GPa to 340 GPa. The improved hardness, reduced value of Er/ H and the ceramic nature of the oxide layer has considerably improved the load bearing capacity and tribological properties of the iron aluminide. The coefficient of friction of the TO treated alloy is low and stable, and the wear rate for the TO treated alloy canbe more than 16 times less than that for the untreated alloy.
Effect of porosity on thermal response, hardness, hardenability and microstructure of powder metallurgy steels
Authors: Stiles D. J.
Published: April 2005

Pores in sintered steels influence thermal characteristics and hardenability. Instrumented Jominy end quench tests were performed on bars containing thermocouples to measure the cooling rate 5, 25, 45 and 65 mm from the water quenched end of the bar. A three-dimensional finite differencemodel was developed to predict steady state cooling curves at selected sintered densities. Initial results showed a discrepancy between actual and predicted cooling rates, possibly due to the entry of water or steam into the open pores at the quenched face of the sintered Jominy bar. Experimentaldata from instrumented Jominy tests showed that sintered steels, with porosity levels. >10 vol.-% cooled more rapidly than a comparable wrought alloy. Additional instrumented Jominy end quench tests were conducted to determine the role of porosity with respect to the cooling rate, hardness,hardenability and microstructure of two hybrid powder metallurgy (P/M) steels. Several of the Jominy bars were fabricated with the water quenched face sealed by shot peening. Hot isostatic pressing (HIP) was employed to fabricate pore free Jominy specimens, which were used as a baseline forthermal response. Pores enhance the measured cooling rate near the water quenched end of the Jominy bar. Based on a simple heat transfer model, cooling rates increase with decreasing thermal conductivity near the water quenched end of a Jominy bar. The bulk effect of porosity is the opposite.Predictions made by three-dimensional models are consistent with experimentally measured cooling rates in as sintered, shot peened and HIPed P/M steels.
Engagement of specific T-cell surface molecules regulates cytoskeletal polarization in HTLV-1–infected lymphocytes
Authors: Barnard Amanda L. , Igakura Tadahiko , Tanaka Yuetsu , Taylor Graham P. , Bangham Charles R.M.
Published: April 2005

Cell-cell contact is required for efficient transmission of human T-lymphotropic virus type 1 (HTLV-1). An HTLV-1–infected cell polarizes its microtubule-organizing center (MTOC) toward the cell-cell junction; HTLV-1 core (Gag) complexes and the HTLV-1 genome accumulate at the point of contact and are then transferred to the uninfected cell. However, the mechanisms involved in this cytoskeletal polarization and transport of HTLV-1 complexes are unknown. Here, we tested the hypothesis that engagement of a specific T-cell surface ligand is synergistic with HTLV-1 infection in causing polarization of the MTOC to the cell contact region. We show that antibodies to intercellular adhesion molecule-1 (ICAM-1; CD54) caused MTOC polarization at a higher frequency in HTLV-1–infected cells. ICAM-1 is upregulated on HTLV-1–infected cells, and, in turn, ICAM-1 on the cell surface upregulates HTLV-1 gene expression. We propose that a positive feedback loop involving ICAM-1 and HTLV-1 Tax protein facilitates the formation of the virologic synapse and contributes to the T-cell tropism of HTLV-1. In contrast, MTOC polarization induced in T cells by antibodies to CD3 or CD28 was significantly inhibited by HTLV-1 infection.
Lentiviral delivery of short hairpin RNAs protects CD4 T cells from multiple clades and primary isolates of HIV
Authors: Lee Sang-Kyung , Dykxhoorn Derek M. , Kumar Priti , Ranjbar Shahin , Song Erwei , Maliszewski Laura E. , François-Bongarçon Vanessa , Goldfeld Anne , Swamy N. Manjunath , Lieberman Judy , Shankar Premlata
Published: April 2005

Viral heterogeneity is a major hurdle for potential therapeutic use of RNA interference (RNAi) against HIV-1. To determine the extent of RNAi tolerance to mutations, we tested 3 viral target sites with differing propensity for mutations: a highly variable rev sequence, a gag sequence conserved only among clade B isolates, and a vif sequence highly conserved across clades. Lentiviral expression of all 3 shRNAs inhibited replication of the homologous HIVIIIB strain. However, they differed in their ability to protect primary CD4 T cells against multiple isolates within and across HIV clades. The least conserved rev sequence inhibited only 2 of 5 clade B isolates. The gag sequence (conserved within clade B) protected 5 of 5 clade B isolates but not other clade viruses with 2 or 3 mutations in the central region. In contrast, the vif sequence, which was conserved across clades except for single mutations at positions 14 and 17, inhibited viruses from 5 different clades. Moreover, siRNAs with introduced mutations at sites of gag sequence polymorphisms showed reduced antiviral activity, whereas mutations in vif siRNA only modestly decreased silencing. Thus, although 1 or 2 mutations at peripheral sites are tolerated, mutations in the central target cleavage region abolish RNAi activity.
Negative regulation of platelet function by a secreted cell repulsive protein, semaphorin 3A
Authors: Kashiwagi Hirokazu , Shiraga Masamichi , Kato Hisashi , Kamae Tsuyoshi , Yamamoto Naoko , Tadokoro Seiji , Kurata Yoshiyuki , Tomiyama Yoshiaki , Kanakura Yuzuru
Published: April 2005

Semaphorin 3A (Sema3A) is a secreted disulfide-bound homodimeric molecule that induces growth cone collapse and repulsion of axon growth in the nervous system. Recently, it has been demonstrated that Sema3A is produced by endothelial cells and inhibits integrin function in an autocrine fashion. In this study, we investigated the effects of Sema3A on platelet function by using 2 distinct human Sema3A chimera proteins. We detected expression of functional Sema3A receptors in platelets and dose-dependent and saturable binding of Sema3A to platelets. Sema3A dose-dependently inhibited activation of integrin αIIbβ3byall agonists examined including adenosine diphosphate (ADP), thrombin, convulxin, phorbol 12-myristate 13-acetate, and A23187. Sema3A inhibited not only platelet aggregation induced by thrombin or collagen but also platelet adhesion and spreading on immobilized fibrinogen. Moreover, Sema3A impaired αIIbβ3-independent spreading on glass coverslips and aggregation-independent granular secretion. Sema3A inhibited agonist-induced elevation of filamentous action (F-actin) contents, phosphorylation of cofilin, and Rac1 activation. In contrast, Sema3A did not affect the levels of cyclic nucleotides or agonist-induced increase of intracellular Ca2+ concentrations. Thus, the extensive inhibition of platelet function by Sema3A appears to be mediated, at least in part, through impairment of agonist-induced Rac1-dependent actin rearrangement.
Production and characterization of erythropoietic protoporphyric heterodimeric ferrochelatases
Authors: Najahi-Missaoui Wided , Dailey Harry A.
Published: April 2005

Mutations resulting in diminished activity of the dimeric enzyme ferrochelatase are a prerequisite for the inherited disorder erythropoietic protoporphyria (EPP). Patients with clinical EPP have only 10% to 30% of normal levels of ferrochelatase activity, and although many patients with EPP have one mutant allele and one “low-expression” normal allele, the possibility remains that, for some, low ferrochelatase activity may result from an EPP mutation that has an impact on both subunits of the wild-type/mutant heterodimer. Here we present data for 12 ferrochelatase wild-type/EPP mutant heterodimers showing that some mutations result in heterodimers with the residual activity anticipated from individual constituents, whereas others result in heterodimers with significantly lower activity than would be predicted. Although the data do not allow an a priori prediction of heterodimeric residual activity based solely on the in vitro activity of EPP homodimers or the position of the mutated residue within ferrochelatase, mutations that affect the dimer interface or [2Fe-2S] cluster have a significantly greater impact on residual activity than would be predicted. These data suggest that some EPP mutations may result in clinically overt EPP in the absence of a low-expression, wild-type allele; this is of potential significance for genetic counseling of patients with EPP.
CD144 (VE-cadherin) is transiently expressed by fetal liver hematopoietic stem cells
Authors: Kim Injune , Yilmaz Ömer H. , Morrison Sean J.
Published: April 2005

Hematopoietic stem cells (HSCs) and endothelial progenitors arise from a common embryonic precursor. However, these populations diverge prior to the onset of definitive hematopoiesis, as HSCs become CD45+ and are thought to lose the expression of endothelial markers. After the onset of definitive hematopoiesis, CD144 (vascular endothelial [VE]–cadherin) has been considered a specific marker of endothelial cells. In contrast, we found that virtually all HSC activity from embryonic day 13.5 (E13.5) fetal liver was CD144+. CD144 expression declined on E16.5 fetal liver HSCs and was absent from adult bone marrow HSCs. This identified a new marker that is differentially expressed between fetal and adult HSCs, and enhanced the purification of HSCs from the E13.5 fetal liver. These results emphasize the close developmental relationship between hematopoietic and endothelial cells, while indicating that CD144 is not a specific marker of endothelial cells during fetal development.
Acute myeloid leukemia bearing cytoplasmic nucleophosmin (NPMc+ AML) shows a distinct gene expression profile characterized by up-regulation of genes involved in stem-cell maintenance
Authors: Alcalay Myriam , Tiacci Enrico , Bergomas Roberta , Bigerna Barbara , Venturini Elisa , Minardi Simone P. , Meani Natalia , Diverio Daniela , Bernard Loris , Tizzoni Laura , Volorio Sara , Luzi Lucilla , Colombo Emanuela , Lo Coco Francesco , Mecucci Cristina , Falini Brunangelo , Pelicci Pier Giuseppe ,   for the Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto (GIMEMA) Acute Leukemia Working Party
Published: April 2005

Approximately one third of acute myeloid leukemias (AMLs) are characterized by aberrant cytoplasmic localization of nucleophosmin (NPMc+ AML), consequent to mutations in the NPM putative nucleolar localization signal. These events are mutually exclusive with the major AML-associated chromosomal rearrangements, and are frequently associated with normal karyotype, FLT3 mutations, and multilineage involvement. We report the gene expression profiles of 78 de novo AMLs (72 with normal karyotype; 6 without major chromosomal abnormalities) that were characterized for the subcellular localization and mutation status of NPM. Unsupervised clustering clearly separated NPMc+ from NPMc– AMLs, regardless of the presence of FLT3 mutations or non–major chromosomal rearrangements, supporting the concept that NPMc+ AML represents a distinct entity. The molecular signature of NPMc+ AML includes up-regulation of several genes putatively involved in the maintenance of a stem-cell phenotype, suggesting that NPMc+ AML may derive from a multipotent hematopoietic progenitor.
Resistance to hepcidin is conferred by hemochromatosis-associated mutations of ferroportin
Authors: Drakesmith Hal , Schimanski Lisa M. , Ormerod Emma , Merryweather-Clarke Alison T. , Viprakasit Vip , Edwards Jon P. , Sweetland Emma , Bastin Judy M. , Cowley Diana , Chinthammitr Yingyong , Robson Kathryn J. H. , Townsend Alain R. M.
Published: April 2005

Ferroportin (FPN) mediates iron export from cells; FPN mutations are associated with the iron overloading disorder hemochromatosis. Previously, we found that the A77D, V162del, and G490D mutations inhibited FPN activity, but that other disease-associated FPN variants retained full iron export capability. The peptide hormone hepcidin inhibits FPN as part of a homeostatic negative feedback loop. We measured surface expression and function of wild-type FPN and fully active FPN mutants in the presence of hepcidin. We found that the Y64N and C326Y mutants of FPN are completely resistant to hepcidin inhibition and that N144D and N144H are partially resistant. Hemochromatosis-associated FPN mutations, therefore, either reduce iron export ability or produce an FPN variant that is insensitive to hepcidin. The former mutation type is associated with Kupffer-cell iron deposition and normal transferrin saturation in vivo, whereas patients with the latter category of FPN mutation have high transferrin saturation and tend to deposit iron throughout the liver parenchyma. FPN-linked hemochromatosis may have a variable pathogenesis depending on the causative FPN mutant.
Nonhemolytic antibody-induced loss of erythrocyte surface antigen
Authors: Zimring James C. , Hair Gregory A. , Chadwick Traci E. , Deshpande Seema S. , Anderson Kimberly M. , Hillyer Christopher D. , Roback John D.
Published: April 2005

Transfusion of red blood cells (RBCs) into patients with anti–donor RBC antibodies (crossmatch-incompatible transfusion) can result in lethal antibody-mediated hemolysis. Less well appreciated is the ability of anti-RBC antibodies to specifically remove their target antigen from donor RBCs without compromising cell survival or adversely affecting the transfusion recipient. In an effort to elucidate the mechanistic details of this process, we describe the first animal model of nonhemolytic antibody-induced RBC antigen loss. RBCs from transgenic mHEL mice express surface hen egg lysozyme (HEL) as a transmembrane protein. Transfusion of mHEL RBCs into mice immunized with HEL results in selective loss of HEL antigen from donor RBCs without affecting other blood group antigens or reducing the circulatory life span of the transfused RBCs. While this process does not require the presence of a spleen, it requires both anti-RBC immunoglobulin G (IgG) antibodies and the FcγIII receptor. These studies provide mechanistic insight into the phenomenon of antigen loss during incompatible transfusion in humans.
Subfunctionalization of duplicated genes as a transition state to neofunctionalization
Authors: Rastogi Shruti , Liberles David A
Published: April 2005

Background

Gene duplication has been suggested to be an important process in the generation of evolutionary novelty. Neofunctionalization, as an adaptive process where one copy mutates into a function that was not present in the pre-duplication gene, is one mechanism that can lead to the retention of both copies. More recently, subfunctionalization, as a neutral process where the two copies partition the ancestral function, has been proposed as an alternative mechanism driving duplicate gene retention in organisms with small effective population sizes. The relative importance of these two processes is unclear.

Results

A set of lattice model genes that fold and bind to two peptide ligands with overlapping binding pockets, but not a third ligand present in the cell was designed. Each gene was duplicated in a model haploid species with a small constant population size and no recombination. One set of models allowed subfunctionalization of binding events following duplication, while another set did not allow subfunctionalization. Modeling under such conditions suggests that subfunctionalization plays an important role, but as a transition state to neofunctionalization rather than as a terminal fate of duplicated genes. There is no apparent selective pressure to maintain redundancy.

Conclusion

Subfunctionalization results in an increase in the preservation of duplicated gene copies, including those that are neofunctionalized, but never represents a substantial fraction of duplicate gene copies at any evolutionary time point and ultimately leads to neofunctionalization of those preserved copies. This conclusion also may reflect changes in gene function after duplication with time in real genomes.
Use of adenoviral E1A protein to analyze K18 promoter deregulation in colon carcinoma cells discloses a role for CtBP1 and BRCA1
Authors: Delouis Cécile , Prochasson Philippe , Laithier Madeleine , Brison Olivier
Published: April 2005

Background

The promoter of the keratin 18 (K18) gene is 5- to 10-fold more active in tumorigenic (T-type) cell clones derived from the SW613-S human colon carcinoma cell line than in non-tumorigenic (NT-type) clones. We have reported previously that the mechanism responsible for this differential activity is acting on the minimal K18 promoter (TATA box and initiation site). This mechanism does not require the binding of a factor to a specific site on the DNA but involves the acetylation of a non-histone substrate. To get further insight into this mechanism, we investigated the effect of the adenovirus E1A protein on the activity of the K18 promoter, both in T and NT cells.

Results

Wild type adenovirus E1A protein and C-terminal deletion mutants inhibit the K18 promoter, specifically in T-type cells. The domain responsible for this inhibitory effect is located in the 12–25 region of the viral protein. E1A mutants that have lost this region but retain the PLDLS motif (the C-terminal binding site for CtBP1) stimulate the K18 promoter, specifically in NT cells. The inhibitory or stimulatory effects of the different E1A mutants are not dependent on a particular sequence of the promoter. An E1A N-terminal deletion mutant carrying point mutations in the PLDLS motif cannot stimulate the K18 promoter. CtBP1 interacts with CtIP, which is a known partner of BRCA1, itself a component of the RNA polymerase II holoenzyme. The stimulatory effect of two BRCA1 mutants, specifically in NT cells, implicates a tripartite BRCA1-CtIP-CtBP1 complex in the regulation of the K18 promoter.

Conclusion

Since we have shown previously that the K18 promoter is stimulated by deacetylase inhibitors, specifically in NT cells, we conclude that the activity of the promoter is repressed in NT cells by a mechanism involving the recruitment, by a BRCA1/CtIP complex, of CtBP1 and associated deacetylases to the preinitiation complex. We propose a model depicting the mechanism responsible for the differential activity of the K18 promoter between T and NT cells of the SW613-S cell line.
Comparing protocols for preparation of DNA-free total yeast RNA suitable for RT-PCR
Authors: Del Aguila Eduardo M , Dutra Marcio B , Silva Joab T , Paschoalin Vânia MF
Published: April 2005

Background

Preparation of RNA free from DNA is a critical step before performing RT-PCR assay. Total RNA isolated from several sources, including those obtained from Saccharomyces cerevisiae, using routine methodologies are frequently contaminated with DNA, which can give rise to amplification products that mimic the amplicons expected from the RNA target.

Results

We investigated the efficiency of two DNase I based protocols for eliminating DNA contaminations from RNA samples obtained from yeast cells. Both procedures are very efficient in eliminating DNA contamination from RNA samples and entail three main steps, which involve treating of RNA samples with DNase I, inhibition of the enzyme by EDTA and its subsequent inactivation at 65°C. The DNase I treated samples were further purified with phenol: chloroform followed by precipitation with ice-cold ethanol (protocol I) or, alternatively, they were directly used in RT-PCR reactions (protocol II). Transcripts from ACT1, PDA1, CNA1, CNA2, TPS1 and TPS2 analyzed after each treatment showed that all mRNAs tested can be amplified if total RNA was extracted and purified after DNase I treatment, however, only TPS1, TPS2 and ACT1 mRNAs were amplified without extraction/purification step.

Conclusion

Although more laborious and requiring a higher initial amount of material, the inclusion of an extraction and purification step allows to prepare RNA samples that are free from DNA and from low molecular contaminants and can be applied to amplify any Saccharomyces cerevisiae mRNA by RT-PCR.
Identifying future models for delivering genetic services: a nominal group study in primary care
Authors: Elwyn Glyn , Edwards Adrian , Iredale Rachel , Davies Peter , Gray Jonathon
Published: April 2005

Background

To enable primary care medical practitioners to generate a range of possible service delivery models for genetic counselling services and critically assess their suitability.

Methods

Modified nominal group technique using in primary care professional development workshops.

Results

37 general practitioners in Wales, United Kingdom too part in the nominal group process. The practitioners who attended did not believe current systems were sufficient to meet anticipated demand for genetic services. A wide range of different service models was proposed, although no single option emerged as a clear preference. No argument was put forward for genetic assessment and counselling being central to family practice, neither was there a voice for the view that the family doctor should become skilled at advising patients about predictive genetic testing and be able to counsel patients about the wider implications of genetic testing for patients and their family members, even for areas such as common cancers. Nevertheless, all the preferred models put a high priority on providing the service in the community, and often co-located in primary care, by clinicians who had developed expertise.

Conclusion

There is a need for a wider debate about how healthcare systems address individual concerns about genetic concerns and risk, especially given the increasing commercial marketing of genetic tests.
Cerebral infarction in diabetes: Clinical pattern, stroke subtypes, and predictors of in-hospital mortality
Authors: Arboix Adrià , Rivas Antoni , García-Eroles Luis , de Marcos Lourdes , Massons Joan , Oliveres Montserrat
Published: April 2005

Background

To compare the characteristics and prognostic features of ischemic stroke in patients with diabetes and without diabetes, and to determine the independent predictors of in-hospital mortality in people with diabetes and ischemic stroke.

Methods

Diabetes was diagnosed in 393 (21.3%) of 1,840 consecutive patients with cerebral infarction included in a prospective stroke registry over a 12-year period. Demographic characteristics, cardiovascular risk factors, clinical events, stroke subtypes, neuroimaging data, and outcome in ischemic stroke patients with and without diabetes were compared. Predictors of in-hospital mortality in diabetic patients with ischemic stroke were assessed by multivariate analysis.

Results

People with diabetes compared to people without diabetes presented more frequently atherothrombotic stroke (41.2% vs 27%) and lacunar infarction (35.1% vs 23.9%) (P < 0.01). The in-hospital mortality in ischemic stroke patients with diabetes was 12.5% and 14.6% in those without (P = NS). Ischemic heart disease, hyperlipidemia, subacute onset, 85 years old or more, atherothrombotic and lacunar infarcts, and thalamic topography were independently associated with ischemic stroke in patients with diabetes, whereas predictors of in-hospital mortality included the patient's age, decreased consciousness, chronic nephropathy, congestive heart failure and atrial fibrillation

Conclusion

Ischemic stroke in people with diabetes showed a different clinical pattern from those without diabetes, with atherothrombotic stroke and lacunar infarcts being more frequent. Clinical factors indicative of the severity of ischemic stroke available at onset have a predominant influence upon in-hospital mortality and may help clinicians to assess prognosis more accurately.
Comparison of SPECT bone scintigraphy with MRI for diagnosis of meniscal tears
Authors: Tahmasebi Mohammad-naghi , Saghari Mohsen , Moslehi Masoud , Gholamrezanezhad Ali
Published: April 2005

Background

Scintigraphy has been considered as competitive to MRI, but limited data are available on the accuracy of single photon emission tomography (SPECT) compared with MRI for the assessment of meniscal tears. Our objective was to assess the value of SPECT in comparison to MRI.

Methods

Between January 2003 and March 2004, sixteen patients were studied with both modalities and the accuracy rates of SPECT scan results, and MRI findings in the diagnosis of meniscal tears were compared. Arthroscopy was the gold standard.

Results

The respective sensitivity rate, specificity rate, and positive and negative predictive accuracies of MRI were 89%, 94%, 93%, and 79% and for SPECT those were 78%, 94%, 94%, and 88%. There was good agreement on the presence or absence of tears between two modalities (κ statistic = 0.699).

Conclusion

SPECT and MRI are both valuable imaging techniques. SPECT is a useful alternative when MRI is unavailable or unsuitable and it is beneficial when more possible accuracy is desired (such as when MRI results are either inconclusive or conflict with other clinical data).
Rare mutations predisposing to familial adenomatous polyposis in Greek FAP patients
Authors: Mihalatos Markos , Apessos Angela , Dauwerse Hans , Velissariou Voula , Psychias Aristidis , Koliopanos Alexander , Petropoulos Konstantinos , Triantafillidis John K , Danielidis Ioannis , Fountzilas George , Agnantis Niki J , Nasioulas Georgios
Published: April 2005

Background

Familial Adenomatous Polyposis (FAP) is caused by germline mutations in the APC (Adenomatous Polyposis Coli) gene. The vast majority of APC mutations are point mutations or small insertions / deletions which lead to truncated protein products. Splicing mutations or gross genomic rearrangements are less common inactivating events of the APC gene.

Methods

In the current study genomic DNA or RNA from ten unrelated FAP suspected patients was examined for germline mutations in the APC gene. Family history and phenotype were used in order to select the patients. Methods used for testing were dHPLC (denaturing High Performance Liquid Chromatography), sequencing, MLPA (Multiplex Ligation – dependent Probe Amplification), Karyotyping, FISH (Fluorescence In Situ Hybridization) and RT-PCR (Reverse Transcription – Polymerase Chain Reaction).

Results

A 250 Kbp deletion in the APC gene starting from intron 5 and extending beyond exon 15 was identified in one patient. A substitution of the +5 conserved nucleotide at the splice donor site of intron 9 in the APC gene was shown to produce frameshift and inefficient exon skipping in a second patient. Four frameshift mutations (1577insT, 1973delAG, 3180delAAAA, 3212delA) and a nonsense mutation (C1690T) were identified in the rest of the patients.

Conclusion

Screening for APC mutations in FAP patients should include testing for splicing defects and gross genomic alterations.
Immune function biomarkers in children exposed to lead and organochlorine compounds: a cross-sectional study
Authors: Karmaus Wilfried , Brooks Kevin R , Nebe Thomas , Witten Jutta , Obi-Osius Nadia , Kruse Hermann
Published: April 2005

Background

Different organochlorines and lead (Pb) have been shown to have immunomodulating properties. Children are at greater risk for exposure to these environmental toxicants, but very little data exist on simultaneous exposures to these substances.

Methods

We investigated whether the organochlorine compounds (OC) dichlorodiphenylethylene (DDE), hexachlorobenzene (HCB), hexachlorocyclohexane (γ-HCH), the sum of polychlorinated biphenyls (ΣPCBs) and Pb were associated with immune markers such as immunoglobulin (Ig) levels, white blood cell (WBC), counts of lymphocytes; eosinophils and their eosinophilic granula as well as IgE count on basophils. The investigation was part of a cross-sectional environmental study in Hesse, Germany. In 1995, exposure to OC and Pb were determined, questionnaire data collected and immune markers quantified in 331 children. For the analyses, exposure (OC and Pb) concentrations were grouped in quartiles (γ-HCH into tertiles). Using linear regression, controlling for age, gender, passive smoking, serum lipids, and infections in the previous 12 months, we assessed the association between exposures and immune markers. Adjusted geometric means are provided for the different exposure levels.

Results

Geometric means were: DDE 0.32 μg/L, ΣPCBs 0.50 μg/L, HCB 0.22 μg/L, γ-HCH 0.02 μg/L and Pb 26.8 μg/L. The ΣPCBs was significantly associated with increased IgM levels, whereas HCB was inversely related to IgM. There was a higher number of NK cells (CD56+) with increased γ-HCH concentrations. At higher lead concentrations we saw increased IgE levels. DDE showed the most associations with significant increases in WBC count, in IgE count on basophils, IgE, IgG, and IgA levels. DDE was also found to significantly decrease eosinophilic granula content.

Conclusion

Low-level exposures to OC and lead (Pb) in children may have immunomodulating effects. The increased IgE levels, IgE count on basophils, and the reduction of eosinophilic granula at higher DDE concentrations showed a most consistent pattern, which could be of clinical importance in the etiology of allergic diseases.