bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk of Acute Brain Injury Related to Cerebral Microembolism During Cardiac Catheterization Performed by Right Upper Limb Arterial Access
Authors: Hamon Michèle , Gomes Sophie , Clergeau Marie-Rose , Fradin Sabine , Morello Rémy , Hamon Martial
Published: May 2007

Background and Purpose—

The primary objective of this study was to assess the incidence of new cerebral infarcts related to cardiac catheterization in patients explored through the right transradial approach.

Methods—

This prospective study involved 41 consecutive patients with severe aortic valve stenosis. To assess the incidence of cerebral infarction, all patients underwent cerebral diffusion-weighted MRI before and after cardiac catheterization through the right transradial approach.

Results—

We detected only two patients (4.9%) with new, small, isolated acute cerebral diffusion abnormalities postcatheterization. All patients remained asymptomatic.

Conclusions—

New cerebral lesions on diffusion-weighted MRI are infrequent in patients explored through the right transradial approach. Randomized studies are warranted to confirm for potential advantages of transradial approach versus the femoral approach in cardiac catheterization.
Ocean Eddy Dynamics in a Coupled Ocean–Atmosphere Model*
Authors: Berloff P. , Dewar W. , Kravtsov S. , McWilliams J.
Published: May 2007

The role of mesoscale oceanic eddies is analyzed in a quasigeostrophic coupled ocean–atmosphere model operating at a large Reynolds number. The model dynamics are characterized by decadal variability that involves nonlinear adjustment of the ocean to coherent north–south shifts of the atmosphere. The oceanic eddy effects are diagnosed by the dynamical decomposition method adapted for nonstationary external forcing. The main effects of the eddies are an enhancement of the oceanic eastward jet separating the subpolar and subtropical gyres and a weakening of the gyres. The flow-enhancing effect is due to nonlinear rectification driven by fluctuations of the eddy forcing. This is a nonlocal process involving generation of the eddies by the flow instabilities in the western boundary current and the upstream part of the eastward jet. The eddies are advected by the mean current to the east, where they backscatter into the rectified enhancement of the eastward jet. The gyre-weakening effect, which is due to the time-mean buoyancy component of the eddy forcing, is a result of the baroclinic instability of the westward return currents. The diagnosed eddy forcing is parameterized in a non-eddy-resolving ocean model, as a nonstationary random process, in which the corresponding parameters are derived from the control coupled simulation. The key parameter of the random process—its variance—is related to the large-scale flow baroclinicity index. It is shown that the coupled model with the non-eddy-resolving ocean component and the parameterized eddies correctly simulates climatology and low-frequency variability of the control eddy-resolving coupled solution.
Wave–Current Interaction: A Comparison of Radiation-Stress and Vortex-Force Representations
Authors: Lane E. M. , Restrepo J. M. , McWilliams J. C.
Published: May 2007

The vortex-force representation of the wave-averaged effects on currents is compared to the radiation-stress representation in a scaling regime appropriate to coastal and shelf waters. Three-dimensional and vertically integrated expressions for the conservative current equations are obtained in both representations. The vortex-force representation decomposes the main wave-averaged effects into two physically understandable concepts—a vortex force and a Bernoulli head. The vortex force is shown to be the dominant wave-averaged effect on currents. This effect can occur at higher order than the apparent leading order for the radiation-stress representation. Excluding nonconservative effects such as wave breaking, the lowest-order radiation or interaction stress can be completely characterized in terms of wave setup, forcing of long (infragravity) waves, and an Eulerian current whose divergence cancels that of the primary wave Stokes drift. The leading-order, wave-averaged dynamical effects incorporate the vortex force together with material advection by Stokes drift, modified pressure-continuity and kinematic surface boundary conditions, and parameterized representations of wave generation by the wind and breaking near the shoreline.
Satellite-Derived Surface Current Divergence in Relation to Tropical Atlantic SST and Wind
Authors: Helber Robert W. , Weisberg Robert H. , Bonjean Fabrice , Johnson Eric S. , Lagerloef Gary S. E.
Published: May 2007

The relationships between tropical Atlantic Ocean surface currents and horizontal (mass) divergence, sea surface temperature (SST), and winds on monthly-to-annual time scales are described for the time period from 1993 through 2003. Surface horizontal mass divergence (upwelling) is calculated using surface currents estimated from satellite sea surface height, surface vector wind, and SST data with a quasi-linear, steady-state model. Geostrophic and Ekman dynamical contributions are considered. The satellite-derived surface currents match climatological drifter and ship-drift currents well, and divergence patterns are consistent with the annual north–south movement of the intertropical convergence zone (ITCZ) and equatorial cold tongue evolution. While the zonal velocity component is strongest, the meridional velocity component controls divergence along the equator and to the north beneath the ITCZ. Zonal velocity divergence is weaker but nonnegligible. Along the equator, a strong divergence (upwelling) season in the central/eastern equatorial Atlantic peaks in May while equatorial SST is cooling within the cold tongue. In addition, a secondary weaker and shorter equatorial divergence occurs in November also coincident with a slight SST cooling. The vertical transport at 30-m depth, averaged across the equatorial Atlantic Ocean between 2°S and 2°N for the record length, is 15(±6) × 106 m3 s−1. Results are consistent with what is known about equatorial upwelling and cold tongue evolution and establish a new method for observing the tropical upper ocean relative to geostrophic and Ekman dynamics at spatial and temporal coverage characteristic of satellite-based observations.
Diagnosis of the Vertical Motions in a Mesoscale Stirring Region
Authors: Legal Cédric , Klein Patrice , Treguier Anne-Marie , Paillet Jerome
Published: May 2007

A high-resolution survey was conducted as part of the 2001 Programme Ocean Multidisciplinaire Meso Echelle (POMME 2) experiment in a region of the northeast Atlantic Ocean characterized by a large number of strongly interacting mesoscale eddies. The survey was located between mesoscale eddies in an area where the horizontal stirring processes were dominant. Diagnosis, using SeaSoar data combined with the analysis of altimeter data, reveals an energetic vertical velocity field involving elongated thin structures with alternate signs and amplitude up to 20 m day−1. The 3D dynamics involved in the appearance of these vertical motions is the restoration of the thermal wind balance within the small-scale density filaments that are elongated by the stirring processes. These experimental results reinforce the conclusions of previous numerical studies pointing out the necessity to explicitly include the effects of the filamentation process in ocean models.
Oceanic Isopycnal Slope Spectra. Part I: Internal Waves
Authors: Klymak Jody M. , Moum James N.
Published: May 2007

Horizontal tow measurements of internal waves are rare and have been largely supplanted in recent decades by vertical profile measurements. Here, estimates of isotherm displacements and turbulence dissipation rate from a towed vehicle deployed near Hawaii are presented. The displacement data are interpreted in terms of horizontal wavenumber spectra of isopycnal slope. The spectra span scales from 5 km to 0.1 m, encompassing both internal waves and turbulence. The turbulence subrange is identified using a standard turbulence fit, and the rest of the motions are deemed to be internal waves. The remaining subrange has a slightly red slope (ϕ ∼ k−1/2x) and vertical coherences compatible with internal waves, in agreement with previous towed measurements. However, spectral amplitudes in the internal wave subrange exhibit surprisingly little variation despite a four-order-of-magnitude change in turbulence dissipation rate observed at the site. The shape and amplitude of the horizontal spectra are shown to be consistent with observations and models of vertical internal wave spectra that consist of two subranges: a “linear” subrange (ϕ ∼ k0z) and a red “saturated” subrange (ϕ ∼ k−1z). These two subranges are blurred in the transformation to horizontal spectra, yielding slopes close to those observed. The saturated subrange does not admit amplitude variations in the spectra yet is an important component of the measured horizontal spectra, explaining the poor correspondence with the dissipation rate.
Leadership, Authority, and Collective Action
Authors: Einwohner Rachel L.
Published: May 2007

This article examines leadership and its role in the emergence of collective action with a comparison of resistance activities in two Jewish ghettos in Nazi-occupied Europe. In the Warsaw Ghetto, Jews rose up in armed rebellion against the Nazis twice during 1943; in contrast, Jewish activists in the Vilna Ghetto planned for similar resistance, but a sustained uprising never took place. The author argues that these different outcomes can be attributed in part to the resistance fighters' “authority work,” or efforts made to establish their credibility in the eyes of each community; activists in Warsaw performed this work successfully, whereas those in Vilna did not engage in this work at all. The lack of authority work in Vilna was especially damaging because of the actions of another authoritative ghetto leader, who persuaded the community to oppose resistance efforts. The findings suggest that authority work varies across different movement settings and is particularly important in the context of uncertainty.
Leading Tasks in a Leaderless Movement
Authors: Earl Jennifer
Published: May 2007

Leadership has proven a difficult concept to define, with the proliferation of definitions of leadership being more notable than any individual definition. This article takes a different approach to understanding leadership dynamics by identifying and studying “leading tasks.” Specifically, tasks associated with leadership in existing research are enumerated. Using data on two “strategic voting” mobilizations in 2000 and 2004, the empirical salience of various leading tasks to key organizers is traced and explained. The data suggest that although leadership was not evident in strategic voting, organizers did identify, prioritize, and take action on specific leading tasks.
Edward Shils' Theory of Tradition
Authors: Jacobs Struan
Published: May 2007

Edward Shils presented his book Tradition (1981) as the first extensive study of the subject. This article casts light on Shils' multifaceted understanding of tradition, comprising pragmatic, Burkean, veridical, and evolutionist perspectives. His typology of traditions is noted, and his view of institutional bearers of tradition described. In assessing Shils' theory, however, we find that it overreaches, collapsing differences that exist between traditions, transmissions, and the traditional.
Do We Need Mechanisms in the Social Sciences?
Authors: Reiss Julian
Published: May 2007

A recent movement in the social sciences and philosophy of the social sciences focuses on mechanisms as a central analytical unit. Starting from a pluralist perspective on the aims of the social sciences, I argue that there are a number of important aims to which knowledge about mechanisms—whatever their virtues relative to other aims—contributes very little at best and that investigating mechanisms is therefore a methodological strategy with fairly limited applicability.
Popper's Theory of the Closed Society Conflicts with His Theory of Research
Authors: Wettersten John
Published: May 2007

Popper's theory of the attraction of closed societies conflicts with his theory of research: the former sees rational thought as contrary to man's nature, whereas the latter sees it as an innate psychological process. This conflict arose because Popper developed a theory of the movement from the closed society—Heimat—to civilized society, which sees civilized society as a burden, before he adapted Selz's view of directed thought processes as problem solving, which sees rationality as natural. Rejecting the earlier view and retaining the latter one opens up possibilities for better explanations of closed societies and better means of combating them.
Cutaneous Hemangioma Associated With Persistence of the Trigeminal and Both Proatlantal Arteries
Authors: Pascual-Castroviejo I. , Lopez-Gutierrez J.C.
Published: May 2007

The authors describe a girl who was evaluated at 7 years old because of facial segmental hemangioma associated with unilateral persistent trigeminal artery, bilateral proatlantal arteries, hypoplasia of 1 posterior cerebral artery, kinking of 1 internal carotid artery at 2 different levels, and transdural collateral vascularization supplying the posterior areas of the cerebral hemispheres. This is the first patient known to have a cutaneous hemangioma associated with bilateral proatlantal arteries despite having a unilateral facial hemangioma.
Carpal Tunnel Syndrome in Children With Mucopolysaccaridoses
Authors: Yuen Alex , Dowling Guy , Johnstone Bruce , Kornberg Andrew , Coombs Christopher
Published: May 2007

Carpal tunnel syndrome in children is uncommon. Mucopolysaccharidosis is the most common cause of carpal tunnel syndrome in this age group. With new treatment modalities available for mucopolysaccaridoses, the prognosis of the disease has greatly improved. The musculoskeletal manifestations including carpal tunnel syndrome now assume more importance. Early diagnosis and treatment of carpal tunnel syndrome in these children are important to achieve a good outcome. The authors present their experience in the management of children with mucopolysaccharidosis and carpal tunnel syndrome.
Postterm Closure of the Cavum Septi Pellucidi and Developmental Outcome in Premature Infants
Authors: Needelman Howard , Schroeder Bruce , Sweeney Matthew , Schmidt John , Bodensteiner John B. , Schaefer G.B.
Published: May 2007

The authors report the natural history of closure of the cavum Septi pellucidi in premature infants 26 to 27 weeks postconception at birth and compare the developmental outcome in these infants who had closure by 42 weeks postconception to those who still had a cavum septum pellucidi visualized on ultrasound at approximately term (35-42 weeks). Of 72 patients, 35 patients still had a cavum septum pellucidi visualized on the last ultrasound done between 35 and 42 weeks postconception, and the developmental outcome of these patients was no different from those with earlier closure. The authors conclude that persistence of a cavum septi pellucidi through term is not an independent risk factor for developmental delay.
Prognosis of Patients With Seizures Occurring in the First 2 Years
Authors: Altunbaşak Şakir , Incecik Faruk , Hergüner Özlem , Refik Burgut H.
Published: May 2007

The aim of this study is to determine the prognosis of patients with seizure onset from 1 to 24 months of age in respect to epilepsy, developmental outcome, and neurological status. It also aims to determine predictive factors regarding an unfavorable prognosis. Seventy-five patients were retrospectively analyzed. Univariate analysis revealed the following findings: (1) mental retardation at initial admission, abnormal neurological finding, infantile spasm, use of more than 1 antiepileptic drug, epileptic activity on electroencephalography (EEG) of neonatal seizure, and perinatal anoxia were significant risk factors with regard to developmental outcome; (2) mental retardation at initial admission, abnormal neurological finding, infantile spasm, use of more than 1 antiepileptic drug, epileptic activity on EEG, symptomatic etiology, history of neonatal seizure, and perinatal anoxia were significant risk factors regarding neurological status; and (3) mental retardation at initial admission, neurological abnormality, infantile spasm, use of more than 1 antiepileptic drug, epileptic activity on EEG, status epilepticus, symptomatic etiology, seizure frequency of more than once per week, history of perinatal anoxia, and neonatal seizure were significant risk factors regarding epilepsy prognosis. In addition, multivariate analysis revealed that neurological abnormality and use of more than 1 antiepileptic drug were significant for developmental outcome, that epileptic activity on EEG and use of more than 1 antiepileptic drug were significant for neurological status, and that perinatal anoxia, infantile spasm, and status epilepticus were significant for epilepsy prognosis. These findings suggest that neurological abnormality, use of more than 1 antiepileptic drug, infantile spasm, status epilepticus, and perinatal anoxia are unfavorable predictive risk factors regarding the prognosis of patients with seizures that have an onset from 1 to 24 months of age.
Explaining Responses to Volunteering: An Ecological Model
Authors: Kulik Liat
Published: May 2007

The author examined responses to volunteering as expressed in satisfaction with volunteering and burnout. The research sample consisted of 275 volunteers (212 women and 63 men) in various types of social service organizations in Israel. Based on Bronfenbrenner's ecological model, the author examined the contribution of variables from three ecological systems to explaining the outcome variables: (a) the ontogenic system (gender, age, education, and economic situation) and personality characteristics (self-esteem and empowerment), (b) the micro system (family context and volunteer context), and (c) the macro system, including variables reflecting cultural norms, as expressed in ethnic origin. Empowerment, self-esteem, and sociodemographic variables were the main variables related to satisfaction and burnout.
Public Policy Grant Making: Building Organizational Capacity Among Nonprofit Grantees
Authors: Mandeville John
Published: May 2007

Federal restrictions deter the involvement of private foundations in public policy making. In the 2000 grant year, public policy grant makers funded approximately 15,000 public policy grants worth more than $2.4 billion. These funds support the actions of nonprofit “policy actors.” Previous research suggests that funders that are committed to exerting influence in a policy system will invest in policy actor capacity development. This study seeks to identify the practice of funder investment in policy actor capacity. Three areas of capacity development are considered: research and communication capacity, resources acquisition capacity, and management and governance capacity. Consideration is also given to the concept of “holistic investment.” Are funders concerned with the overall capacity of the organization or just with specific dimensions of capacity? Records of grants made by 407 of the largest foundations in the United States serve as the data for the study.
Dielectric and Electromechanical Behaviors of PMN—PT Ceramic Samples
Authors: Skulski Ryszard , Wawrzała Paweł , Ćwikiel Krzysztof , Bochenek Dariusz
Published: May 2007

The results of the investigations on (1 — x)PMN-xPT ceramic samples obtained by sol—gel (SG) technology are presented in this study. In the (1 — x)PMN-xPT samples, the temperature Tm (at which real part of dielectric permittivity reaches its maximum) increases from ~270 K for x = 0 to ~500 K for x = 0.5. At room temperature, the samples with low values of x exhibit relaxor properties, while with increasing x the transition to normal ferroelectric properties takes place. Usually 0.9PMN-0.1PT or 0.925PMN-0.075PT solid solutions are considered as boundary compositions between relaxor and ferroelectric properties at room temperature.This study presents the analysis of X-ray diffraction patterns, fracture microphotographs, electromechanical parameters, and hysteresis loops for ceramics obtained from SG PMN—PT powders densified by the hot pressing method with a composition range, x = 0—0.37.
Strength Problem in the Design of Smart Structures
Authors: Piening Matthias
Published: May 2007

It is a common practice to design an actuator system for maximum structural efficiency. Thus the design is driven by the ratio of output to input in terms of force and stroke. As the action of the actuator and the reaction of the elastic body are dependent on the material properties, it is mandatory to know the stress distributions within the elastic body system and the associated strength limits. In order to avoid local failure and degradation due to fatigue, it is necessary to consider the local stress conditions in the early design process. The integrated actuator is an elastic body like the surrounding body system, with individual structural behavior and strength properties. Both together are exposed to the stresses and strains caused by the action of the actuator and the operational loads which act on the whole system at the same time, i.e., mechanical, thermal, or moisture loads. The presently used 2D models are well suited to predict the strength behavior of homogeneous metallic structures. But as soon as the elastic body system becomes inhomogeneous, has a complex shape, or is anisotropic, the solutions are at least questionable. Transverse stresses cannot be calculated and the effect of changes in the layer stacking sequence can not be estimated. But the results of static and fatigue tests showed a strong dependence of the failure behavior on the stacking order. The inverse physical problem is the action of active layers in a laminate. The placement of active layers within the cross section has a decisive effect on the long-term efficiency of the active laminate. Therefore it is to be taken into account in the early design phase.
Numerical Analysis of Nonlocal Anisotropic Continuum Damage
Authors: Ricci Sabine , Brünig Michael
Published: May 2007

This article deals with the numerical analysis of anisotropic continuum damage in ductile metals based on thermodynamic laws and nonlocal theories. The proposed model is based on a generalized macroscopic theory within the framework of nonlinear continuum damage mechanics taking into account the kinematic description of the damage. A generalized yield condition is employed to describe the plastic flow characteristics of the matrix material, whereas the damage criterion provides a realistic representation of material degradation. The nonlocal theory of inelastic continua is established, which incorporates the macroscopic interstate variables and their higher-order gradients which properly describe the change in the internal structure and investigate the size effect of statistical inhomogeneity of the heterogeneous material. The idea of bridging length scales is made by using the higher-order gradients only in the evolution equations of the equivalent inelastic strain measures. This leads to a system of elliptic partial differential equations which is solved using the finite difference method. The applicability of the proposed continuum damage theory is demonstrated by finite element analyses of the inelastic deformation process of tension specimens.
Elasto-damage Model for High Strength Concrete Subjected to Multiaxial Loading
Authors: Khan A.R. , Al-Gadhib A.H. , Baluch M.H.
Published: May 2007

An effective compliance matrix Č is proposed to model the behavior of concrete based on phenomenological evidence and physical insight. Three parameters α, β, and γ are introduced in the effective compliance matrix Č. α and β are introduced to model the different behavior of concrete in tension and compression, while the third parameter γ is introduced to account for volumetric change. The predictive capability of the proposed elasto-damage model for uniaxial and multiaxial stress paths is investigated for uniaxial compression, biaxial compression, triaxial compression, uniaxial tension, and tension—compression— compression. The simulative capability of the model to capture the phenomenological behavior of concrete such as strain softening, stiffness degradation, biaxial strength envelope, volumetric dilatation, different behavior in tension and compression, and gain in strength under increasing confinement is reflected. The predicted results correlate well with the available experimental data.
Determination of Functional Outcome Following Upper Extremity Arterial Trauma
Authors: Joshi Vijay , Harding Gregory E.J. , Bottoni David A. , Lovell Marge B. , Forbes Thomas L.
Published: May 2007

Upper extremity arterial trauma may lead to significant disability with a poor functional outcome. This study represents a retrospective review of all trauma patients presenting to a university-affiliated medical center. Patients suffering from upper extremity arterial injuries requiring treatment were identified. The injured vessels were identified along with the mechanism of injury and method of repair. The degree of functional disability was evaluated by using a previously validated questionnaire, the Disabilities of the Arm, Shoulder, and Hand (DASH) Outcome Measure. Between September 1999 and December 2004, 17 patients presented with traumatic arterial injury to the upper extremity, with 9 and 8 patients suffering from blunt and penetrating traumas, respectively. One patient required amputation representing a limb salvage rate of 94%. The mean length of hospitalization was significantly shorter for penetrating trauma (5.1 vs 12 days, P = .03), with blunt trauma victims being more prone to coexisting orthopedic injuries ( P = .009). Length of follow-up did not differ between the 2 groups and ranged from 1-60 months. Patients with blunt trauma tended, although not statistically significant, to have higher DASH scores (61.8 vs 22.8, P = .08), indicating a greater degree of disability. By utilizing a validated disability questionnaire, this study confirms that patients suffering from blunt injuries to upper extremity arteries are more likely to have greater degrees of disability affecting everyday activities.
Is Incidental Renal Arteriography Justified in a Population of Patients with Symptomatic Peripheral Arterial Disease?
Authors: Androes Mark P. , Langan Eugene M. , Kalbaugh Corey A. , Blackhurst Dawn W. , Taylor Spence M. , Youkey Jerry R.
Published: May 2007

Renal artery stenosis is a consequence of generalized atherosclerosis and many specialists perform routine selective renal angiography to detect and treat renal artery stenosis. The incidence of clinically important renal artery stenosis is not well defined in patients with symptomatic peripheral arterial disease. The purpose of this study was to better delineate the incidence of and the risk factors associated with renal artery stenosis, renovascular hypertension, and ischemic nephropathy incidentally discovered during angiography for symptomatic peripheral arterial disease. Two hundred consecutive patients undergoing angiographic evaluation of symptomatic lower extremity peripheral arterial disease were studied retrospectively. Angiograms were reviewed for the presence of renal artery stenosis (defined as ≥ 25% diameter reduction in either renal artery) and findings were then correlated to the clinical diagnosis of renovascular hypertension (> 50% renal artery stenosis and ≥ 3-drug resistive hypertension) and ischemic nephropathy (defined as > 50% bilateral renal artery stenosis, 3-drug hypertension, and creatinine ≥ 1.5). Angiographic findings were also correlated with risk factors to determine if a relationship correlated to the presence of and degree of renal artery stenosis. Data were analyzed using the Student's t test, Chi-square model, and multiple logistic regression analysis. The overall incidence of any degree of renal artery stenosis in this study population was 26% (52 patients). Only 24 (12%) patients had an incidental finding of ≥ 50% stenosis in either renal artery. Six (3%) of these patients were found to have associated renovascular hypertension. Additionally, 9 (4.5%) patients had coexistent renal insufficiency and significant renal artery stenosis; five with end-stage renal disease on chronic hemodialysis. Only one patient with end-stage renal disease had poorly controlled 3-drug hypertension. Thus definitive ischemic nephropathy was present in only one (0.5%) patient. Statistically significant risk factors associated with the presence of renal artery stenosis include hypertension ( P < .001), coronary disease ( P = .024), female gender ( P = .010), diabetes ( P = .039), aorto-iliac disease ( P = .031), multiple levels of peripheral arterial disease ( P < .001), and age over 60 ( P < .001). While the incidence of renal artery stenosis in patients being evaluated for symptomatic peripheral arterial disease is similar to that reported in the cardiology literature, the incidence of renovascular hypertension and ischemic nephropathy is exceedingly low (3% and 0.5%, respectively)—findings similar to data reported in the general hypertensive population. These data suggest that incidental selective renal angiography is not justified in patients with symptomatic peripheral arterial disease.
Systemic Thrombolysis Using Tissue Plasminogen Activator for a Patient with Paradoxic Embolism: A Case Report
Authors: Fan Zhen , Roedersheimer Richard , Lohr Joann
Published: May 2007

When thrombotic material that originates from deep venous thrombosis of the lower extremities is washed out into the pulmonary vasculature, pulmonary embolization occurs. Pulmonary embolism and associated acute peripheral ischemia suggest the diagnosis of paradoxic embolism, which is most often associated with a patent foramen ovale. Therapeutic options include anticoagulation, mechanical/chemical thrombus dissolution, inferior vena cava filtration, and closure of the intracardiac defect. The diagnosis and treatment are described of an elderly female who presented with lower extremity deep venous thrombosis and massive pulmonary embolism complicated by paradoxic emboli to the left subclavian artery as well as the celiac artery.
Basic Science Review: Characterization of Endoleak Following Endovascular Repair of Abdominal Aortic Aneurysms
Authors: Chaer Rabih A. , DeRubertis Brian G. , Trocciola Susan , Hynecek Robert , Lin Stephanie C. , Lam Russell , Kent K. Craig , Faries Peter L.
Published: May 2007

Aneurysm models have been developed to study the pathobiology of abdominal aortic aneurysm and to evaluate the efficacy of endovascular therapy. The purpose of this review is to describe the use and limitations of current animal and experimental models for the characterization of endoleak following endovascular repair of abdominal aortic aneurysms.
Spiral Saphenous Vein Graft for Portal Vein Reconstruction in Pancreatic Cancer Surgery
Authors: Chiu Kuan-Ming , Chu Shu-Hsun , Chen Jer-Shen , Li Shao-Jung , Chan Chih-Yang , Chen Kuo-Shin
Published: May 2007

The curative strategy for most pancreatic cancer is surgical resection. Extensive resection with lymph node dissection is the key to providing long-term survival. However, early diagnosis of pancreatic cancer is not always possible (ie, resectability is limited). One reason for such a nonresectable condition is vascular invasion or encasement. Portal vein involvement has been a contraindication for pancreatic cancer surgery for most general surgeons. Combining oncologic and vascular surgeons in the procedure has been a good solution. A multidisciplinary approach that includes general and vascular surgeons is appropriate in selected patients requiring vascular reconstruction at the time of pancreatectomy. The objective of this paper is to report a case in which spiral saphenous vein was used for portal vein reconstruction during pancreatic cancer resection.
Endovascular Stent Exclusion of a Hepatic Artery Pseudoaneurysm
Authors: deFreitas Dorian , Phade Sachin , Stoner Michael , Bogey William , Powell Charles S. , Parker Frank
Published: May 2007

Presented is a patient with an iatrogenic hepatic artery pseudoaneurysm that was treated by endovascular stent grafting. Endovascular stent grafting of a hepatic artery pseudoaneurysm offers a safe and potentially less morbid alternative to an open repair. The report stresses the necessity of careful preoperative evaluation with angiography to determine the feasibility of the procedure. An aggressive approach to treating hepatic artery pseudoaneurysms is advocated because of the poor correlation between size and their tendency to rupture. With an increasing rate of diagnosis of visceral artery aneurysms in elderly, debilitated patients, endovascular repair is anticipated to have an increasing role and should be considered a first-line therapy in anatomically suitable candidates.
Multipotent cells can be generated in vitro from several adult human organs (heart, liver, and bone marrow)
Authors: Beltrami Antonio P. , Cesselli Daniela , Bergamin Natascha , Marcon Patrizia , Rigo Silvia , Puppato Elisa , D'Aurizio Federica , Verardo Roberto , Piazza Silvano , Pignatelli Angela , Poz Alessandra , Baccarani Umberto , Damiani Daniela , Fanin Renato , Mariuzzi Laura , Finato Nicoletta , Masolini Paola , Burelli Silvia , Belluzzi Ottorino , Schneider Claudio , Beltrami Carlo A.
Published: May 2007

The aims of our study were to verify whether it was possible to generate in vitro, from different adult human tissues, a population of cells that behaved, in culture, as multipotent stem cells and if these latter shared common properties. To this purpose, we grew and cloned finite cell lines obtained from adult human liver, heart, and bone marrow and named them human multipotent adult stem cells (hMASCs). Cloned hMASCs, obtained from the 3 different tissues, expressed the pluripotent state–specific transcription factors Oct-4, NANOG, and REX1, displayed telomerase activity, and exhibited a wide range of differentiation potential, as shown both at a morphologic and functional level. hMASCs maintained a human diploid DNA content, and shared a common gene expression signature, compared with several somatic cell lines and irrespectively of the tissue of isolation. In particular, the pathways regulating stem cell self-renewal/maintenance, such as Wnt, Hedgehog, and Notch, were transcriptionally active. Our findings demonstrate that we have optimized an in vitro protocol to generate and expand cells from multiple organs that could be induced to acquire morphologic and functional features of mature cells even embryologically not related to the tissue of origin.
A2A adenosine receptors and C/EBPβ are crucially required for IL-10 production by macrophages exposed to Escherichia coli
Authors: Csóka Balázs , Németh Zoltán H. , Virág László , Gergely Pál , Leibovich S. Joseph , Pacher Pál , Sun Chun-Xiao , Blackburn Michael R. , Vizi E. Sylvester , Deitch Edwin A. , Haskó György
Published: May 2007

We recently showed that A2A adenosine receptor activation by endogenous adenosine contributes to interleukin-10 (IL-10) production in polymicrobial sepsis. Here we investigated the molecular mechanisms underpinning this interaction between adenosine receptor signaling and infection by exposing macrophages to Escherichia coli. We demonstrated using receptor knockout mice that A2A receptor activation is critically required for the stimulatory effect of adenosine on IL-10 production by E coli–challenged macrophages, whereas A2B receptors have a minor role. The stimulatory effect of adenosine on E coli–induced IL-10 production did not require toll-like receptor 4 (TLR4) or MyD88, but was blocked by p38 inhibition. Using shRNA we demonstrated that TRAF6 impairs the potentiating effect of adenosine. Measuring IL-10 mRNA abundance and transfection with an IL-10 promoter-luciferase construct indicated that E coli and adenosine synergistically activate IL-10 transcription. Sequential deletion analysis and site-directed mutagenesis of the IL-10 promoter revealed that a region harboring C/EBP binding elements was responsible for the stimulatory effect of adenosine on E coli–induced IL-10 promoter activity. Adenosine augmented E coli–induced nuclear accumulation and DNA binding of C/EBPβ. C/EBPβ-deficient macrophages failed to produce IL-10 in response to adenosine and E coli. Our results suggest that the A2A receptor–C/EBPβ axis is critical for IL-10 production after bacterial infection.
ATF2 impairs glucocorticoid receptor–mediated transactivation in human CD8+ T cells
Authors: Li Ling-bo , Leung Donald Y. M. , Strand Matthew J. , Goleva Elena
Published: May 2007

Chronic inflammatory diseases often have residual CD8+ T-cell infiltration despite treatment with systemic corticosteroids, which suggests divergent steroid responses between CD4+ and CD8+ cells. To examine steroid sensitivity, dexamethasone (DEX)–induced histone H4 lysine 5 (K5) acetylation and glucocorticoid receptor α (GCRα) translocation were evaluated. DEX treatment for 6 hours significantly induced histone H4 K5 acetylation in normal CD4+ cells (P = .001) but not in CD8+ cells. DEX responses were functionally impaired in CD8+ compared with CD4+ cells when using mitogen-activated protein kinase phosphatase (1 hour; P = .02) and interleukin 10 mRNA (24 hours; P = .004) induction as a readout of steroid-induced transactivation. Normal DEX-induced GCRα nuclear translocation and no significant difference in GCRα and GCRβ mRNA expression were observed in both T-cell types. In addition, no significant difference in SRC-1, p300, or TIP60 expression was found. However, activating transcription factor-2 (ATF2) expression was significantly lower in CD8+ compared with CD4+ cells (P = .009). Importantly, inhibition of ATF2 expression by small interfering RNA in CD4+ cells resulted in inhibition of DEX-induced transactivation in CD4+ cells. The data indicate refractory steroid-induced transactivation but similar steroid-induced transrepression of CD8+ cells compared with CD4+ cells caused by decreased levels of the histone acetyltransferase ATF2.
Diverse histone modifications on histone 3 lysine 9 and their relation to DNA methylation in specifying gene silencing
Authors: Wu Jiejun , Wang Shu-Huei , Potter Dustin , Liu Joseph C , Smith Laura T , Wu Yue-Zhong , Huang Tim H-M , Plass Christoph
Published: May 2007

Background

Previous studies of individual genes have shown that in a self-enforcing way, dimethylation at histone 3 lysine 9 (dimethyl-H3K9) and DNA methylation cooperate to maintain a repressive mode of inactive genes. Less clear is whether this cooperation is generalized in mammalian genomes, such as mouse genome. Here we use epigenomic tools to simultaneously interrogate chromatin modifications and DNA methylation in a mouse leukemia cell line, L1210.

Results

Histone modifications on H3K9 and DNA methylation in L1210 were profiled by both global CpG island array and custom mouse promoter array analysis. We used chromatin immunoprecipitation microarray (ChIP-chip) to examine acetyl-H3K9 and dimethyl-H3K9. We found that the relative level of acetyl-H3K9 at different chromatin positions has a wider range of distribution than that of dimethyl-H3K9. We then used differential methylation hybridization (DMH) and the restriction landmark genome scanning (RLGS) to analyze the DNA methylation status of the same targets investigated by ChIP-chip. The results of epigenomic profiling, which have been independently confirmed for individual loci, show an inverse relationship between DNA methylation and histone acetylation in regulating gene silencing. In contrast to the previous notion, dimethyl-H3K9 seems to be less distinct in specifying silencing for the genes tested.

Conclusion

This study demonstrates in L1210 leukemia cells a diverse relationship between histone modifications and DNA methylation in the maintenance of gene silencing. Acetyl-H3K9 shows an inverse relationship between DNA methylation and histone acetylation in regulating gene silencing as expected. However, dimethyl-H3K9 seems to be less distinct in relation to promoter methylation. Meanwhile, a combination of epigenomic tools is of help in understanding the heterogeneity of epigenetic regulation, which may further our vision accumulated from single-gene studies.
Absidia Corymbiferain an immune competent accident victim with multiple abdominal injuries: case report
Authors: Belfiori Rita , Terenzi Adelmo , Marchesini Laura , Repetto Antonella
Published: May 2007

Background

We report a case of mucormycosis in a healthy 17-year-old accident victim with multiple abdominal injuries which was caused by infection with Absidia Corymbifera, a ubiquitous saphrophyte in the ground.

Case presentation

The patient was admitted to hospital with massive abdominal trauma. During an 8-hour emergency operation he received transfusions of compacted red blood cells, plasma, platelets and hemagel. He developed a crush syndrome with acute renal failure, resolved with extra-corporeal dialysis and had to undergo splenectomy because of spleen hematoma. As wound secretion and central venous catheter (CVC) blood cultures and drainage fluid were positive for Enterococcus Faecium, Providentia Rettgeri, Hafnia Alvei and Candida Albicans, tecoplanin, metronidazole, imipenem, and flucanozole were administered.

Although the CVC was changed high fever persisted and discharge continued from the large abdominal wound. Repeated tampons in different sections and wound secretion smears were positive for A. corymbifera. Flucanozole was stopped and liposomal amphotericin (Ambisome; 5 mg/Kg i.v.) given for over 3 months.

The patient improved; fever gradually disappeared. After 8 days, tampons and wound secretion smears were negative for A. corymbifera. No other fungal infections developed. Drainage fluid was later positive for tecoplanin-resistant E. faecium and Pseudomonas Aeroginosa responding only to meropenem and ciprofloxacin. Abdominal computerized tomography visualized fluid accumulation around the iliac-femoral bypass. Abcess was ruled out when scintigraphy showed no tracer uptake. The lesion was drained. Drainage fluid cultures were negative for bacteria and fungi. Fluid accumulation gradually disappeared with prolonged antibiotic and antifungal therapy.

One year after the accident the patient is in good health, with normal quality of life.

Conclusion

Successful outcome was due to early, specific antifungal therapy, at sufficiently high dosage which was prolonged for an adequate period of time. Early diagnosis of mucormycosis is essential for efficacious anti-fungal treatment and prevention of irreversible spread of mucormycosis to vital organs. It presupposes awareness that A. corymbifera infection can develop in healthy individuals who are stressed and traumatized through skin-ground contact in accidents.
Expression of inflammatory host genes in Chlamydia trachomatis-infected human monocytes
Authors: Schrader Sina , Klos Andreas , Hess Simone , Zeidler Henning , Kuipers Jens G , Rihl Markus
Published: May 2007

The aim of this study was to perform a comprehensive gene expression analysis of cytokines, chemokines, and their receptors in Chlamydia trachomatis-infected human monocytes in order to elucidate molecular aspects of their involvement in the host response. Peripheral blood mononuclear cells from three healthy donors were separated and infected with C. trachomatis elementary bodies serovar K (UW/31/Cx) at a multiplicity of infection of 5:1. Three time points of infection were studied by gene expression analysis using microarray: 4 hours (active infection), 1 day (transition), and 7 days (persistent infection). Expression levels of selected genes were confirmed by quantitative real-time reverse transcription-polymerase chain reaction. Transcripts encoding 10 cytokines, chemokines, and receptors were found to be upregulated exclusively in the early, active phase of the infection as compared to four genes in the late, persistent state of the infection. Apart from receptors, both the level and the number of transcripts encoding inflammatory products decreased with ongoing infection. Four genes (interferon-gamma, macrophage inflammatory protein [MIP]-1-alpha, MIP-1-beta, and interleukin-2 receptor-gamma) were constantly expressed over a period of 7 days. The current study provides data on the induction of mRNA encoding cytokines, chemokines, and their receptors in C. trachomatis-infected human monocytes. This pro-inflammatory gene expression profile of the monocytic host cell showed several differences between active and persistent chlamydial infections.
Stat3 is tyrosine-phosphorylated through the interleukin-6/glycoprotein 130/Janus kinase pathway in breast cancer
Authors: Berishaj Marjan , Gao Sizhi Paul , Ahmed Simi , Leslie Kenneth , Al-Ahmadie Hikmat , Gerald William L , Bornmann William , Bromberg Jacqueline F
Published: May 2007

Introduction

Signal transducer and activator of transcription 3 (Stat3) is constitutively tyrosine-phosphorylated in approximately 50% of primary breast carcinomas. A number of different mechanisms responsible for Stat3 activation, including abnormal activation of receptor tyrosine kinases, Src, and Janus kinases (Jaks), have been implicated in breast cancer.

Methods

We examined six breast cancer-derived cell lines expressing high or low levels of tyrosine-phosphorylated Stat3 (pStat3) as well as primary breast cancer specimens.

Results

Inhibition of Src or EGFR (epidermal growth factor receptor) tyrosine kinases had no effect on pStat3 levels, whereas pan-Jak inhibitor P6 resulted in complete abrogation of Stat3 phosphorylation and inhibition of growth. Jaks are required for cytokine signaling, and the glycoprotein 130 (gp130) receptor-associated Jaks are known mediators of Stat3 phosphorylation. Blockade of the gp130 receptor or sequestration of the interleukin-6 (IL-6) ligand led to a decrease of pStat3 levels. Conditioned media from those cell lines expressing high levels of pStat3 contained IL-6 and were capable of stimulating Stat3 phosphorylation. We examined IL-6 levels in primary breast tumors and found a positive correlation between pStat3 and IL-6 expression.

Conclusion

In summary, a principal mechanism of Stat3 activation in breast cancer is through the IL-6/gp130/Jak pathway.