Challenging

Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Challenging

  • diagnostically challenging
  • very challenging

  • Terms modified by Challenging

  • challenging application
  • challenging area
  • challenging aspect
  • challenging behavior
  • challenging behaviour
  • challenging case
  • challenging condition
  • challenging environment
  • challenging issue
  • challenging issues
  • challenging nature
  • challenging problem
  • challenging procedure
  • challenging process
  • challenging question
  • challenging situation
  • challenging task

  • Selected Abstracts


    Predictors of smoking relapse by duration of abstinence: findings from the International Tobacco Control (ITC) Four Country Survey

    ADDICTION, Issue 12 2009
    Natalie Herd
    ABSTRACT Aim To explore predictors of smoking relapse and how predictors vary according to duration of abstinence. Design, setting and participants A longitudinal survey of 1296 ex-smokers recruited as part of the International Tobacco Control (ITC) Four Country Survey (Australia, Canada, United Kingdom and United States). Measurements Quitters were interviewed by telephone at varying durations of abstinence (from 1 day to approximately 3 years) and then followed-up approximately 1 year later. Theorized predictors of relapse (i.e. urges to smoke; outcome expectancies of smoking and quitting; and abstinence self-efficacy) and nicotine dependence were measured in the survey. Findings Relapse was associated with lower abstinence self-efficacy and a higher frequency of urges to smoke, but only after the first month or so of quitting. Both these measures mediated relationships between perceived benefits of smoking and relapse. Perceived costs of smoking and benefits of quitting were unrelated to relapse. Conclusions Challenging perceived benefits of smoking may be an effective way to increase abstinence self-efficacy and reduce frequency of urges to smoke (particularly after the initial weeks of quitting), in order to reduce subsequent relapse risk. [source]


    Multiresponsive, Hierarchically Structured Membranes: New, Challenging, Biomimetic Materials for Biosensors, Controlled Release, Biochemical Gates, and Nanoreactors

    ADVANCED MATERIALS, Issue 2 2009
    Ihor Tokarev
    Multifunctional responsive gel membranes present a new and promising platform for the development of "smart" devices for bioseparation, biosensors, and "smart" drug release. These membranes combine the functions of stimuli-responsive control and regulation of the mass transport with a range of properties, such as storage, catalysis of chemical reactions, antimicrobial activity, and optical signal transduction. [source]


    Ectopic pregnancy: Challenging accepted management strategies

    AUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 4 2009
    George CONDOUS
    Ectopic pregnancy is still the number one cause of maternal deaths in early pregnancy. The diagnostic capabilities of transvaginal ultrasound to confirm an EP are well founded. In fact, ultrasound technology, particularly the introduction of high-resolution transvaginal probes, has been the driving force behind the revolutionary change towards conservative management strategies in ectopic pregnancy care. Clinically stable women, however, with a scan diagnosis of a tubal ectopic pregnancy still routinely undergo surgery or are given methotrexate (MTX) at presentation. Conservative management for ectopic pregnancy may be considered in the context of clinical stability. Reassessment at 48 h allows evaluation of the trophoblast activity or ,trophoblastic load'. Falling serum hCG levels at 48 h suggest that the ectopic trophoblast is resolving spontaneously and it may be possible to avoid methotrexate administration in this sub-group. Women with increasing serum hCG levels at 48 h, indicating the trophoblast is still active, should be targeted for methotrexate. By calculating the pre-treatment hCG ratio (hCG 48 h/hCG 0 h), it is possible to triage women with an ectopic pregnancy for conservative management. There are, however, no randomised data to support the use of MTX over expectant management. In this review, some of the current management strategies in ectopic pregnancy management will be challenged. [source]


    Emotion Work and Emotion Space: Using a Spatial Perspective to Explore the Challenging of Masculine Emotion Management Practices

    BRITISH JOURNAL OF MANAGEMENT, Issue 2008
    Patricia Lewis
    This paper sets out to investigate the possibility that employees may challenge management through their colonization of work space, facilitated by the transportation of ,private' behaviours and activities into the ,public' world of organization. It does this within the context of a broader project on the management of emotions within a special care baby unit characterized as a high risk, emergency working environment. Focusing on the experience of night nurses and drawing on the concept of differential space the article seeks to demonstrate how the dominant form of emotion work (characterized as masculine) on the unit may be contested. This is done through the creation of the unit at night as a space of empowerment, achieved through the visible enactment of a feminized form of emotion work. In this sense the analysis explores how the performance of feminine emotion work can be understood as acts of spatial resistance to the authority of the masculine emotion regime. In other words night nurses make the special care baby unit into a space which challenges the masculinist emotion management which dominates the unit. It will be suggested that our understanding of the performance of emotion management practices in particular and management practices in general may be limited if space is ignored. [source]


    Setting the agenda: social inclusion, children and young people

    CHILDREN & SOCIETY, Issue 2 2004
    ESRC Seminar Series Participants
    This paper was prepared collectively by participants of the third seminar in a series with the title Challenging ,Social Inclusion': Perspectives for and from Children and Young People. Three 3-day seminars took place at the Universities of Edinburgh, Glasgow and Stirling in 2002,3 attended by academics, professionals from voluntary sector children's agencies, young people, representatives from central government and postgraduate students. Funding was provided by the Economic and Social Research Council (ESRC) and the Children's Society. [source]


    Curve skeleton skinning for human and creature characters

    COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2006
    Xiaosong Yang
    Abstract The skeleton driven skinning technique is still the most popular method for animating deformable human and creature characters. Albeit an industry de facto due to its computational performance and intuitiveness, it suffers from problems like collapsing elbow and candy wrapper joint. To remedy these problems, one needs to formulate the non-linear relationship between the skeleton and the skin shape of a character properly, which however proves mathematically very challenging. Placing additional joints where the skin bends increases the sampling rate and is an ad hoc way of approximating this non-linear relationship. In this paper, we propose a method that is able to accommodate the inherent non-linear relationships between the movement of the skeleton and the skin shape. We use the so-called curve skeletons along with the joint-based skeletons to animate the skin shape. Since the deformation follows the tangent of the curve skeleton and also due to higher sampling rates received from the curve points, collapsing skin and other undesirable skin deformation problems are avoided. The curve skeleton retains the advantages of the current skeleton driven skinning. It is easy to use and allows full control over the animation process. As a further enhancement, it is also fairly simple to build realistic muscle and fat bulge effect. A practical implementation in the form of a Maya plug-in is created to demonstrate the viability of the technique. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Computer programs for estimating substrate flux into steady-state biofilms from pseudoanalytical solutions

    COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2002
    Chetan T. Goudar
    Abstract Fixed-film processes employing microorganisms attached to an inert surface (biofilms) are widely used for biological treatment of municipal and industrial wastewater. For optimal design and analysis of these processes, mathematical models are necessary that describe the dynamics of contaminant transport within these biofilms and the associated contaminant utilization by the microorganisms. However, these governing equations that typically involve Fickian diffusion for contaminant transport and Monod kinetics for contaminant utilization are inherently nonlinear and have no closed form solutions except under special conditions. This can restrict their use in the classroom as cumbersome numerical techniques must be used for their solution. This problem is well documented in the literature and several authors have presented pseudoanalytical solutions that replace numerical solutions with algebraic equations. In the present study, we present pseudoanalytical solution-based computer programs for estimating substrate flux and biofilm thickness for a steady-state biofilm. Depending upon the intended end use, these programs can either partially or totally automate the solution process. In the partial automation mode, they can serve to enhance student understanding of important concepts related to steady-state biofilms, while complete automation can help bring more challenging and realistic problems associated with steady-state biofilms into the classroom. The programs have been tested on MATLAB version 5.0 and are available as freeware for educational purposes. © 2002 Wiley Periodicals, Inc. Comput Appl Eng Educ 10: 26,32, 2002; Published online in Wiley InterScience (www.interscience.wiley.com.); DOI 10.1002/cae.10017 [source]


    Parallel programming on a high-performance application-runtime

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 18 2008
    Wojtek James Goscinski
    Abstract High-performance application development remains challenging, particularly for scientists making the transition to a heterogeneous grid environment. In general areas of computing, virtual environments such as Java and .Net have proved to be successful in fostering application development, allowing users to target and compile to a single environment, rather than a range of platforms, instruction sets and libraries. However, existing runtime environments are focused on business and desktop computing and they do not support the necessary high-performance computing (HPC) abstractions required by e-Scientists. Our work is focused on developing an application-runtime that can support these services natively. The result is a new approach to the development of an application-runtime for HPC: the Motor system has been developed by integrating a high-performance communication library directly within a virtual machine. The Motor message passing library is integrated alongside and in cooperation with other runtime libraries and services while retaining a strong message passing performance. As a result, the application developer is provided with a common environment for HPC application development. This environment supports both procedural languages, such as C, and modern object-oriented languages, such as C#. This paper describes the unique Motor architecture, presents its implementation and demonstrates its performance and use. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Pulmonary Regurgitation after Tetralogy of Fallot Repair: Clinical Features, Sequelae, and Timing of Pulmonary Valve Replacement

    CONGENITAL HEART DISEASE, Issue 6 2007
    Naser M. Ammash MD
    ABSTRACT Pulmonary regurgitation following repair of tetralogy of Fallot is a common postoperative sequela associated with progressive right ventricular enlargement, dysfunction, and is an important determinant of late morbidity and mortality. Although pulmonary regurgitation may be well tolerated for many years following surgery, it can be associated with progressive exercise intolerance, heart failure, tachyarrhythmia, and late sudden death. It also often necessitates re-intervention. Identifying the appropriate timing of such intervention could be very challenging given the risk of prosthetic valve degeneration and the increased risk of reoperation. Comprehensive informed and regular assessment of the postoperative patient with tetralogy of Fallot, including evaluation of pulmonary regurgitation, right heart structure and function, is crucial to the optimal care of these patients. Pulmonary valve replacement performed in an experienced tertiary referral center is associated with low operative morbidity and mortality and very good long-term results. Early results of percutaneous pulmonary valve replacement are also promising. [source]


    Do early therapeutic alliance, motivation, and stages of change predict therapy change for high-risk, psychopathic violent prisoners?

    CRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 2 2010
    Devon L. L. Polaschek
    Background,Examination of the extent of offenders' engagement in change, and in rehabilitation programmes, is important to understanding success or failure following rehabilitation. In treatment programmes, the alliance between therapist and offender, and the therapy process itself appear central to progress offenders make that may reduce their criminal risk. But research with offenders seldom has measured therapeutic alliance and clinical writing suggests that it is difficult to form an alliance with those not ready to change their behaviour; especially with higher risk and psychopathic offenders. Aims and Methods,This study outlines the course of the therapeutic alliance in an 8-month treatment programme for high-risk, PCL-psychopathic violent prisoners. It examines relationships between early-treatment therapeutic alliance, therapists' global ratings of motivation to change, and initial stage of change on dynamic risk factors. In addition, it investigates which factors best predict who will complete treatment and change behaviourally during treatment. Conclusion,In this challenging, high-needs client group, early-programme stage of change, therapists' perceptions of motivation, therapeutic alliance and psychopathy did not predict how much change prisoners made. Regardless of initial levels, prisoners whose alliance increased the most over the course of treatment made the most change. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    CPA assessment , the regional assessors' experience

    CYTOPATHOLOGY, Issue 2007
    G. Guthrie
    With the introduction in January 2006 of the new posts of Regional Assessors, the process and focus of CPA assessment changed to reflect the inclusion in the current standards of Quality Management systems and processes. Regional Assessors, trained in Quality Management Systems and their assessment against international standards, now form a vital part of the CPA assessment teams, looking specifically at this aspect of laboratory service provision. Their role in the new assessment process will be explained. The presentation will cover differences and similarities in the nature and number of non-compliances experienced since April 2006 when the new format of assessment was introduced. It will also look at a new format of timetable for assessment visits and explain the benefits of good two-way communication between all parties involved in the process - the laboratory, the assessors, particularly the Regional Assessor assigned to that site, and CPA Office staff. Understanding what is required by the standards, particularly in terms of evidential material, their interpretation and their classification of status , Critical, Non-Critical or Observation - is an aspect of assessment which is often not well understood. The presentation will seek to clarify these issues. The successful and timely clearance by laboratories of any non-compliances raised during the visits is vital to the achievement of accredited status and the presentation will give guidance as to how this is best achieved. The current standards, based on the international ISO 15189 standards, are considerably more challenging than the old ones. There is now a significant emphasis on Quality Management and its understanding, ethos and implementation within the laboratory, a key element which underpins all aspects of a laboratory's service. The achievement of accredited status assures our users of,the type of client and patient focused service expected of a modern laboratory. [source]


    An Evaluation of Flexible Workday Policies in Job Shops,

    DECISION SCIENCES, Issue 2 2002
    Kum-Khiong Yang
    ABSTRACT Job shops have long faced pressures for improvement in a challenging and volatile environment. Today's trends of global competition and shortening of product life cycles suggest that both the challenges and the intensity of market volatility will only increase. Consequently, the study of tactics for maximizing the flexibility and responsiveness of a job shop is important. Indeed, there is a significant body of literature that has produced guidelines on when and how to deploy tactics such as alternate routings for jobs and transfers of cross-trained workers between machines. In this paper we consider a different tactic by adjusting the length of workdays. Hours in excess of a 40-hour week are exchanged for compensatory time off at time and a half, and the total amount of accrued compensatory time is limited to no more than 160 hours in accordance with pending legislation. We propose several simple flexible workday policies that are based on an input/output control approach and investigate their performance in a simulated job shop. We find significant gains in performance over a fixed schedule of eight hours per day. Our results also provide insights into the selection of policy parameters. [source]


    "Reading Man Flap" Design for Reconstruction of Circular Infraorbital and Malar Skin Defects

    DERMATOLOGIC SURGERY, Issue 11 2008
    TAMER SEYHAN MD
    BACKGROUND Surgical complications such as lid retraction and ectropion from graft or flap scar contracture make reconstruction of skin defects in the malar and infraorbital regions challenging. OBJECTIVE A new flap design, the reading man flap, was used to overcome these problems. The Limberg and bilobed flap were compared with the reading man flap. METHODS The reading man flap consists mainly of a superiorly based quadrangular flap and an inferiorly based triangular flap. Malar and infraorbital circular skin defects measuring 14 × 14 to 40 × 40 mm were reconstructed with a reading man flap in 13 patients. The defects occurred after basal cell carcinoma in all patients. The Limberg flap, bilobed flap, and reading man flap were planned for same-sized defects on the abdominoplasty resection material. The results were compared in terms of total scar area, scar length, and total healthy skin area discarded. RESULTS When comparing the 3 flap designs, the reading man flap was the most suitable flap in terms of total scar area and length. CONCLUSION The reading man flap can be used to reconstruct malar and infraorbital circular defects with good cosmetic results and without creating any tractional forces to the eyelids. [source]


    The oral pathology report: submission of specimens and interpretation of results

    DERMATOLOGIC THERAPY, Issue 3 2002
    Carl M. Allen
    The most accurate histopathologic interpretation of an oral biopsy specimen is often dependent on a variety of factors that may influence the pathologist's analysis of the disease process. Clinical data are often as important as proper sampling or appropriate handling of the biopsy specimen. The oral and maxillofacial pathology laboratory should be considered a useful resource for the diagnosis of oral lesions, particularly those which seem to be more challenging. [source]


    Managing Design for Competitive Advantage A Process Approach

    DESIGN MANAGEMENT REVIEW, Issue 4 2000
    Eric M. Olson
    FOR EXECUTIVES who want to strengthen the design/ business relationship, Eric Olson, Stanley Slater, and Rachel Cooper make some clear recommendations. Make sure designers and design managers understand the organization's competitive strategy; enumerate the design elements inherent in that strategy; nurture open communication between design and other functions; develop design briefs that stimulate creativity at the same time they reinforce business strategy; and measure performance. It's advice that's both sound and challenging. [source]


    MRI-based morphometric analysis of typical and atypical brain development

    DEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 3 2003
    David N. Kennedy
    Abstract The neuroinformatics landscape in which human brain morphometry occurs has advanced dramatically over the past few years. Rapid advancement in image acquisition methods, image analysis tools and interpretation of morphometric results make the study of in vivo anatomic analysis both challenging and rewarding. This has revolutionized our expectations for current and future diagnostic and investigative work with the developing brain. This paper will briefly cover the methods of morphometric analysis that available for neuroanatomic analysis, and tour some sample results from a prototype retrospective database of neuroanatomic volumetric information. From these observations, issues regarding the anatomic variability of developmental maturation of neuroanatomic structures in both typically and atypically developing populations can be discussed. MRDD Research Reviews 2003;9:155,160. © 2003 Wiley-Liss, Inc. [source]


    How can structured self-management patient education improve outcomes in people with type 2 diabetes?

    DIABETES OBESITY & METABOLISM, Issue 1 2010
    J. Jarvis
    Type 2 diabetes (T2DM) is a long-term chronic condition that is complex to manage, with the majority of management being done by the person with diabetes outside of the clinical setting. Because of its complexities, effective self-management requires skills, confidence and the ability to make decisions and choices about treatments and lifestyle on a day-to-day basis. Equipping a person with these self-management skills is in itself challenging and it is now widely accepted that structured education is an integral part of the management of T2DM. This paper explores whether structured self-management education can improve outcomes in people with diabetes. The authors explore what self-management education is, why it is needed and then go on to examine the recent evidence from clinical trials from 2006 onwards. [source]


    Effect of weight-reducing agents on glycaemic parameters and progression to Type 2 diabetes: a review

    DIABETIC MEDICINE, Issue 10 2008
    C. Lloret-Linares
    Abstract Weight loss is associated with improvements in glycaemic control and cardiovascular disease risk factors. However, in the diabetic population, weight management is more challenging, in part because of the weight-promoting effects of the majority of glucose-lowering therapies. This review summarizes evidence from 23 placebo-controlled randomized trials, of at least 1 year duration, on the effects of drugs promoting weight loss (orlistat, sibutramine and rimonabant) on glycaemic variables, diabetes incidence and diabetes control. Fifteen studies of non-diabetic subjects were found, eight of which included a longer treatment period. Eight studies in diabetic patients were reviewed. In non-diabetic subjects, weight loss agents led to a significant improvement in fasting glucose, fasting insulin and insulin resistance. In the diabetic population, glycated haemoglobin decreased by 0.28,1.1% with orlistat and 0.6% with sibutramine and rimonabant. Orlistat reduces progression to diabetes in patients with glucose intolerance treated for 4 years (risk reduction of 45%). In summary, despite leading to only modest weight loss after 12 months, agents promoting weight loss have beneficial effects on glycaemic parameters, glycaemic control and progression to diabetes. These additional benefits of weight loss agents need to be highlighted in order to increase their judicious use in clinical practice, although this may be limited by their well-known adverse side effects. The longer-term safety of these agents beyond a few years is yet to be established. [source]


    Human islet cell transplantation , future prospects

    DIABETIC MEDICINE, Issue 2 2001
    S. A. White
    Summary Background Islet transplantation has the potential to cure diabetes mellitus. Nevertheless despite successful reversal of diabetes in many small animal models, the clinical situation has been far more challenging. The aim of this review is to discuss why insulin-independence after islet allotransplantation has been so difficult to achieve. Methods A literature review was undertaken using Medline from 1975 to July 2000. Results reported to the International Islet Transplant Registry (ITR) up to December 1998 were also analysed. Results Up to December 1998, 405 islet allotransplants have been reported the ITR. Of those accurately documented between 1990 and 1998 (n = 267) only 12% have achieved insulin-independence (greater than 7 days). However with refined peri-transplant protocols insulin indepedence at 1 year can reach 20%. Conclusions There are many factors which can explain the failure of achieving insulin-independence after islet allotransplantation. These include the use of diabetogenic immunosuppressive agents to abrogate both islet allo-immunity and auto-immunity, the critical islet mass to achieve insulin-independence and the detrimental effects of transplanting islets in an ectopic site. However recent evidence most notably from the Edmonton group demonstrates that islet allotransplantation still has great potential to become an established treatment option for diabetic patients. [source]


    Respiratory cytology: Differential diagnosis and pitfalls

    DIAGNOSTIC CYTOPATHOLOGY, Issue 4 2010
    F.R.C.P.C., Ph.D., Reda S. Saad M.D.
    Abstract Pulmonary cytology can be challenging and has its share of diagnostic pitfalls. Reactive atypia can occasionally be alarming, leading to diagnostic pitfall for a false-positive diagnosis of malignancy, even for experienced cytopathologists (Naryshkin and Young, Diagn Cytopathol 1993;9:89,97). In addition, cytologic preparations can show an absence of architectural clues, leading to diagnostic difficulties. Some conditions can cytologically as well as clinically and radiographically mimic malignancies, making these pitfalls even more frequent (Bedrossian et al., Lab Med 1983;14:86,95). A recent report stated that "no laboratory that aims to make definitive diagnoses in pulmonary cytology can be spared from false-positive results"(Policarpio-Nicolas and Wick, Diagn Cytopathol 2008;36:13,19). A false-positive finding could produce unnecessary treatment and morbidity, whereas false-negative diagnosis could result in delayed diagnosis and treatment. This review analyzes and illustrates cellular changes and benign entities that can mimic malignancy in respiratory cytology as well as neoplasms that could lead to a false-negative diagnosis. In addition, some specific challenging and difficult aspects in classification of pulmonary malignancies will be discussed. Guidelines and clues are presented to avoid such pitfalls. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source]


    Diagnosis of metastatic pancreatic mesenchymal tumors by endoscopic ultrasound-guided fine-needle aspiration,

    DIAGNOSTIC CYTOPATHOLOGY, Issue 11 2009
    Linda Varghese M.D.
    Abstract Involvement of the pancreas by metastatic sarcoma is rare, and can prove challenging to differentiate from sarcomatoid carcinomas which occur more commonly. The endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) technique has been successfully used for the diagnosis of pancreatic carcinomas whether primary or metastatic, and is now considered the most effective noninvasive method for the identification of pancreatic metastases. However, to date very few reports detail the diagnosis of mesenchymal neoplasms by EUS-FNA. Herein, we report a series of four patients who underwent EUS-FNA of the pancreas, where the diagnosis of metastatic sarcoma was made based on morphology and ancillary studies. The cases include metastases of leiomyosarcoma, liposarcoma, alveolar rhabdomyosarcoma, and solitary fibrous tumor. The history of a primary sarcoma of the chest wall, mediastinum, and respectively lower extremity was known for the first three of these patients while in the case of the solitary fibrous tumor a remote history of a paraspinal "hemangiopericytoma" was only elicited after the EUS-FNA diagnosis was made. We conclude that EUS-FNA is efficient and accurate in providing a diagnosis of sarcoma, even in patients without a known primary sarcoma, thus allowing institution of therapy without additional biopsies. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source]


    Mixed metaplastic carcinoma of the breast associated with pregnancy: Diagnostic dilemmas in fine-needle aspiration cytology

    DIAGNOSTIC CYTOPATHOLOGY, Issue 10 2009
    Lazaros Skagias M.D.
    Abstract Metaplastic carcinoma of the breast represents a rare entity characterized by the simultaneous presence of ductal, squamous, and/or mesenchymal components in several proportions. There are limitations in fine-needle aspiration diagnosis due to its pathological heterogeneity. When it develops under pregnancy and lactation influence, the cytologic evaluation appears to be more difficult and accurate diagnosis often proves challenging. We describe a case of mixed metaplastic carcinoma with dominant areas of squamous metaplasia, sarcomatoid stroma with spindle cells, and a minor component of cartilaginous metaplasia. We notify our experience in diagnostic approach of this entity focusing on differential diagnosis. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source]


    Differentiating reactive mesothelial cells from metastatic adenocarcinoma in serous effusions: The utility of immunocytochemical panel in the differential diagnosis,

    DIAGNOSTIC CYTOPATHOLOGY, Issue 5 2009
    F.I.A.C., Husain A. Saleh M.D., M.B.A.
    Abstract Differentiating reactive mesothelial cells (RMs) from metastatic adenocarcinoma cells (MAC) in serous fluids based on cytomorphologic features alone can be very challenging. Various immunocytochemical (ICC) markers have been used to maximize the diagnostic accuracy, however, cytopathologists still encounter difficulties in effusion cytologic diagnosis. The aim of this study was to evaluate previous and recent ICC stains to identify the most sensitive and specific markers and the best panel for differentiating RM from MAC. Cell block sections from 41 MAC and 43 RM effusions cases were subjected to ICC staining for MOC-31, BerEp4, carcinoembryonic antigen (CEA), calretinin, HBME-1, CK5/6, and D2-40. For the MAC cases, the sensitivity of BerEp4, MOC-31, and CEA was 82.9, 92.6, and 17%, respectively, and the specificity was 95.3, 93, and 100%, respectively. For the RM cases, the sensitivity of calretinin, CK5/6, D2-40, and HBME-1 was 95.3, 27.9, 58.1, and 93%, respectively, and the specificity was 70.7, 73.1, 75.6, and 82.9%, respectively. The results show that BerEp4 and MOC-31 are highly sensitive and specific for detecting MAC, whereas calretinin and HBME1 are highly sensitive but only modestly specific for detecting RM cases (P < 0.05). Forced entry logistic regression revealed that using MOC-31, BerEp4, HBME-1, and calretinin, is an excellent panel for making correct diagnosis with 97.6% sensitivity in detecting MAC and 90.7% specificity in detecting RM. We conclude that adding a panel of MOC-31, BerEp4, calretinin, and HBME-1 immunostains to routine cytomorphologic features can greatly enhance the diagnostic accuracy of serous effusions. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source]


    Pancreatic mucinous lesions: A retrospective analysis with cytohistological correlation

    DIAGNOSTIC CYTOPATHOLOGY, Issue 11 2006
    Jing Zhai M.D., Ph.D.
    Abstract The diagnosis of mucinous pancreatic lesions, which include mucinous noncystic adenocarcinoma, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), and mucinous metaplasia, is critical, given different clinical management and prognosis. This retrospective study is done to assess the cytological features and pitfalls associated with these entities in cytological samples. A search for pancreatic cytology specimens with histological confirmation of the various pancreatic mucinous lesions was done from 1988 to 2005: 9 mucinous adenocarcinoma, 14 IPMN, 11 MCN, and 3 mucinous metaplasia. The majority (35/37) had been endoscopic ultrasound-guided fine-needle aspirations. The cellularity, background extracellular mucin, epithelial architecture, mucinous nature of the epithelium, cell shape, and nuclear features were evaluated on the cytology material. Of the 22 cytological features evaluated, the presence of three-dimensional clusters, micropapillary structures, and nuclear atypia, which includes nuclear crowding, increased N/C ratio, anisonucleosis, nuclear membrane contour irregularity, clumpy chromatin, and prominent nucleoli, was found to be consistently associated with mucinous adenocarcinoma. There were no statistically significant cytological features, which helped in differentiating IPMN, MCN, and mucinous metaplasia. There was a relatively high false-positive rate in the IPMN group (5/14, 36%). Review of the histological specimen showed severe dysplastic epithelial change in these cases. One false-positive case of mucinous metaplasia (1/3, 33%) showed marked intraepithelial acute inflammation. The cytological diagnosis of mucinous pancreatic lesions remains challenging, except for mucinous noncystic adenocarcinoma. The findings were largely nonspecific in the differentiation between IPMN, MCN, mucinous metaplasia, and incidentally sampled gastrointestinal epithelium. False-positive diagnosis of adenocarcinoma occurs not infrequently in the setting of IPMN with severe dysplastic epithelial change and in lesions with associated acute inflammation, and can be a pitfall in the diagnosis of these lesions. Diagn. Cytopathol. 2006;34: 724,730. © 2006 Wiley-Liss, Inc. [source]


    Nodular fasciitis of parotid region: A pitfall in the diagnosis of pleomorphic adenomas on fine-needle aspiration cytology

    DIAGNOSTIC CYTOPATHOLOGY, Issue 3 2005
    Ph.D., Reda S. Saad M.D.
    Abstract Fine-needle aspiration cytology (FNAC) is routinely employed for the preoperative diagnosis of salivary gland lesions. Although most cases show morphologic features characteristic of specific entities, some lesions can be diagnostically challenging. We report two parotid aspirates, initially diagnosed as pleomorphic adenoma on FNA. The patients, a 33-yr-old white man, and a 24-yr-old white woman, presented with indurated lesions arising in the parotid gland region. The aspirates from both patients were markedly hypercellular. Smears showed a mixture of spindle cells with a well-demarcated cytoplasm showing occasional long cytoplasmic process; and cells with abundant cytoplasm with round to oval eccentric nuclei, giving the impression of plasmacytoid cells of pleomorphic adenoma. The nuclear chromatin was evenly distributed and finely granular with one or two occasional small nucleoli. Intermingled with the tumor cells were scattered neutrophils, eosinophils, and macrophages. Aggregates of spindle cells were also seen embedded in a mucoid background with occasional small tufts of a fibrillar mucoid stroma. These fibrillar tufts were magenta red in the Diff-Quik stain, giving the impression of matrix of pleomorphic adenoma. Both cases were later diagnosed on histologic examination as nodular fasciitis. Nodular fasciitis should be considered in the differential diagnosis of a mass arising in association with the parotid gland. Diagn. Cytopathol. 2005;33:191,194. © 2005 Wiley-Liss, Inc. [source]


    ENDOSCOPIC SUBMUCOSAL DISSECTION IN THE UPPER GASTROINTESTINAL TRACT: PRESENT AND FUTURE VIEW OF EUROPE

    DIGESTIVE ENDOSCOPY, Issue 2009
    Horst Neuhaus
    In Western countries endoscopic mucosal resection (EMR) has been widely accepted for treatment of early Barrett`s neoplasia and flat or depressed colorectal adenomas. In contrast endoscopic submucosal dissection (ESD) is infrequently performed for several reasons. It seems to be difficult to overcome the learning curve of this difficult technique because of the low case volume of early gastric cancer. On the other hand ESD of esophageal or colorectal lesions is even more challenging and is considered to be inappropriate for learning. In addition the indication for esophageal or colorectal ESD is controversial in view of excellent results of the well established EMR technique which is less time-consuming and safer than ESD. A recent survey of leading Western endoscopy centers indicated the limited experience with ESD with a low number of cases for all potential indications. Only a few training courses have been established and the number of ongoing clinical studies is limited. Only 12 out of 340 published articles on "endoscopic mucosal dissection" were reported from Western countries. A better acceptance of ESD requires improvement of the technique to allow an easier, faster and safer approach. There is a strong demand for structured training courses and limitations of human cases to selected centers which participate in prospective trials. A close collaboration between Western and Asian centers is recommended for improvement of the ESD technique and its clinical application. [source]


    On quantitative measures of indirect interactions

    ECOLOGY LETTERS, Issue 4 2007
    Toshinori Okuyama
    Abstract Indirect effects, whether density-mediated (DMII) or trait-mediated (TMII), have been recognized as potentially important drivers of community dynamics. However, empirical studies that have attempted to detect TMII or to quantify the relative strength of DMII and TMII in short-term studies have used a range of different metrics. We review these studies and assess both the consistency of a variety of different metrics and their robustness to (or ability to detect) ecological phenomena such as the dependence of forager behaviour on conspecific density. Quantifying indirect effects over longer time scales when behaviour and population density vary is more challenging, but also necessary if we really intend to incorporate indirect effects into predictions of long-term community dynamics; we discuss some problems associated with this effort and conclude with general recommendations for quantifying indirect effects. [source]


    Interest Rates, Stock Returns and Credit Spreads: Evidence from German Eurobonds

    ECONOMIC NOTES, Issue 1 2005
    Niklas Wagner
    We investigate daily variations in credit spreads on investment-grade Deutschemark-denominated Eurobonds during the challenging 1994,1998 period. Empirical results from a Longstaff and Schwartz (1995) two-factor regression, extended for correlated spread changes and heteroskedasticity, indicate strong persistence in spread changes. Consistent with theory and previous findings, changes in spreads are significantly negatively related to the term-structure level while, contrary to theory, the proxy for asset value does not yield a significant negative contribution. We even find a significant positive relation for Eurobonds with long maturity. Tentative interpretations are portfolio-rebalancing activities or differing risk factor sensitivities on short- vs. long-maturity bonds. [source]


    THE SCHOOL AS AN EXCEPTIONAL SPACE: RETHINKING EDUCATION FROM THE PERSPECTIVE OF THE BIOPEDAGOGICAL

    EDUCATIONAL THEORY, Issue 2 2006
    Tyson E. LewisArticle first published online: 3 MAY 200
    Agamben's theory of the camp provides a challenging, critical vantage point for looking at the ambiguities that emerge from the complex field of disciplinary procedures now prevalent in inner-city, low-income, minority schools, and helps to clarify what exactly is at stake in the symbolic and sometimes physical violence of schooling. Key to understanding the primary relation between camp and classroom is Agamben's framework of the biopolitical, which paradoxically includes life as a political concern through its exclusion from the political sphere. Here Lewis appropriates Agamben's terminology in order to theorize the biopedagogical, wherein educational life is included in schooling through its abandonment. For Lewis, the theory of the camp is necessary to recognizing how schools function and, in turn, how they could function differently. [source]


    A study on video performance of multipoint-to-point video streaming with multiple description coding over ad hoc networks

    ELECTRICAL ENGINEERING IN JAPAN, Issue 4 2010
    Keisuke Utsu
    Abstract Supporting multimedia applications over wireless networks has become a very active research topic recently because video applications are forecast to receive high demand in future wireless networks, such as ad hoc networks. However, enabling video transmission over wireless ad hoc networks is more challenging than over other wireless networks due to node mobility, interference, and the absence of a supporting infrastructure. This paper addresses the problem of video transmission over ad hoc networks. We propose to combine Multiple Description Coding (MDC) with multiple source transport (Multipoint-to-Point transfer: MP2P) in order to maintain smooth video streaming over wireless ad hoc networks. In this paper, we describe a comprehensive simulation and test bed experiment designed to show the effect of the proposed MP2P video transfer with MDC for two description cases of video streaming over wireless ad hoc networks. The results show that the proposed mechanism successfully improves video transfer performance in terms of video packet reachability and throughput. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 43,50, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20999 [source]