bluuebunny/crossref_metadata_2025 huggingface dataset:
Uterine sarcomas versus leiomyomas: Gray‐scale and Doppler sonographic findings
Authors: Aviram Rami , Ochshorn Yifat , Markovitch Ofer , Fishman Ami , Cohen Ilan , Altaras Marco M. , Tepper Ron
Published: December 2004

Purpose

The aim of the study was to evaluate the contribution of gray‐scale sonography and Doppler flow studies in differentiating between uterine sarcomas of different histologic types and leiomyomas.

Patients and Methods

The study included 111 patients, divided retrospectively into 2 groups: 98 patients with leiomyomas and 13 with postoperative diagnosis of uterine sarcoma. This latter group was further divided into a group of 6 patients with uterine leiomyosarcoma and 7 with malignant mixed mesodermal tumor. The gray‐scale sonograms and Doppler parameters in the 3 groups were compared.

Results

The patients with leiomyomas were younger than those with sarcomas (52 years ± 11 versus 65 years ± 15, p < 0.05). No differences were noted between the 3 groups regarding gravidity, parity, symptoms upon admission, or findings during physical examination. The sonographic appearances of the leiomyomas were similar to those of the leiomyosarcomas, but in 6/7 cases, they were different from those of the malignant mixed mesodermal tumors. There was a significant difference between the mean resistance index in arterioles of the leiomyomas (0.59 ± 0.01) and that of the malignant mixed mesodermal tumors (0.41 ± 0.06) (P < 0.001) but not between those of the leiomyomas and the leiomyosarcomas (0.49 ± 0.18).

Conclusions

Doppler flow studies may assist in differentiating between leiomyomas and malignant mixed mesodermal tumors but not between leiomyomas and leiomyosarcomas. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 33:10–13, 2005
Color Doppler sonographic findings in penile fracture
Authors: Kervancioglu Selim , Ozkur Ayhan , Bayram M. Metin
Published: December 2004

We performed color Doppler sonographic examination on 4 patients, 3 of whom had preliminary diagnoses of penile fracture and 1 of whom had undergone an operation due to penile fracture a year previously. Color Doppler sonography helped evaluate the relationships between the hematoma and the vascular structures and aided in differential diagnosis of the vascular injuries that may accompany tunical rupture (or have similar clinical presentations) and Mondor's disease; thus, this method has a crucial role in choosing the treatment approach. Color Doppler sonography may also assist in the follow‐up of patients after surgical or conservative treatment. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 33:38–42, 2005
Transrectal sonographic features of prostatic intraepithelial neoplasia: Correlation with pathologic findings
Authors: Özden Eriz , Göğüş Çağatay , Karamürsel Tamer , Baltacı Sümer , Küpeli Sadettin , Göğüş Orhan
Published: December 2004

Purpose

This study was conducted to evaluate the transrectal sonographic (TRUS) features of prostatic intraepithelial neoplasia (PIN) by comparing the histopathologic results with TRUS findings in patients who had undergone TRUS‐guided prostate biopsy.

Methods

From an initial set of 307 patients who underwent TRUS‐guided prostate biopsy, TRUS findings for 44 patients whose pathologic results were consistent with PIN were reviewed retrospectively. Among these 44 patients, 12 had only PIN, 20 PIN associated with prostatitis, and 12 PIN associated with prostate cancer foci. After exclusion of the foci that included PIN associated with prostatitis and PIN associated with prostate cancer at the same site, the pathologic results for the core specimens from the 100 PIN foci were correlated with TRUS findings according to their location. The sonographic features sought were hypoechoic areas and regions of heterogeneous echogenicity.

Results

Positive TRUS findings were detected in 43% of PIN and 36% of high‐grade PIN (HGPIN) focise. For the HGPIN foci with positive TRUS findings, the detected sonographic features were clusters of millimetric hypoechoic foci (CMHF) (53%), hypoechoic areas with well‐defined borders (27%), and heterogeneous echogenicity (20%) (not significant). The sensitivity of the presence of CMHF for the diagnosis of HGPIN was only 19%.

Conclusions

TRUS‐detected CMHF may indicate HGPIN. Because of the limited sensitivity of this finding, TRUS detection of CMHF does not warrant biopsy, although these lesions warrant close monitoring. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 33:5–9, 2005
Prevalence of carotid artery stenosis in Taiwanese patients with one ischemic stroke
Authors: Tan Teng‐Yeow , Chang Ku‐Chou , Liou Chia‐Wei , Schminke Ulf
Published: December 2004

Purpose

Ethnic differences in the distribution of atherosclerosis in the brain‐supplying vessels are well described. However, only scarce data exist on the prevalence of extracranial carotid artery stenosis in Taiwanese patients who have had a single ischemic stroke.

Methods

Color‐coded duplex sonography was used to evaluate the carotid arteries in a hospital‐based study on 276 consecutive first‐time Taiwanese stroke patients. Significant atherosclerotic lesions of the internal carotid arteries (ICA) were defined as a stenosis of more than 50% or an occlusion.

Results

The prevalence of significant carotid lesions was 6% (35/552) in the entire cohort and 8% (17/224) in patients with hemispheric strokes. Among patients with large‐artery atheroscleroses, according to criteria of the Trial of Org 10172 in Acute Stroke Treatment, only 27% had significant extracranial ICA disease whereas 69% had intracranial vessel stenoses. Older patients tended to have more severe ICA lesions, while other risk factors were not correlated with carotid stenosis.

Conclusion

The prevalence of more than 50% ICA stenosis was low in Taiwanese patients with first hemispheric ischemic strokes, indicating that it is not a major cause of ischemic stroke in this population. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 33:1–4, 2005
Sonography in diagnosis and follow‐up of serosal eosinophilic gastroenteritis treated with corticosteroid
Authors: Buljevac Mladen , Crnčević Urek Marija , Štoos‐Veić Tajana
Published: December 2004

An 18‐year‐old patient presented with abdominal pain, nausea, and low‐grade fever. Sonography showed ascites in the region of the terminal ileum, and the presence of peritoneal nodules suggested peritoneal inflammation. Cytologic analysis of ascites revealed numerous eosinophils. Sonographic visualization of nodular peritoneal deposits associated with eosinophilic ascites permitted the diagnosis of the serosal form of eosinophilic gastroenteritis. The absence of mucosal and muscular involvement in the bowel wall was confirmed by endoscopy and CT. Two weeks of 20 mg/day oral prednisolone led to relief of the patient's symptoms, with normalization of laboratory parameters and sonographic findings. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 33:43–46, 2005
Outcomes Following Liver Transplantation for Seronegative Acute Liver Failure: Experience During a 12-Year Period With More Than 100 Patients
Authors: Wigg Alan J. , Gunson Bridget K. , Mutimer David J.
Published: December 2004

Seronegative hepatitis is a common cause of acute liver failure (ALF) requiring liver transplantation. The primary aim of this study was to examine outcomes following transplantation in this group and to identify factors associated with early (<2 months) mortality. Patients studied were 110 consecutive cases of seronegative ALF transplanted at the Queen Elizabeth Hospital, Birmingham, between January 1992 and January 2004. Univariate analysis of 44 pretransplantation recipient, donor, and operative variables was performed initially to identify factors associated with early posttransplantation mortality. Variables identified as significant or approaching significance were analyzed using stepwise multiple logistic regression analysis. Survival following transplantation for seronegative hepatitis was 83%, 81%, and 73% at 2, 12, and 60 months, respectively. The majority (71%) of deaths occurred within the 1st 2 months and sepsis / multiorgan dysfunction was the most common cause of early death. Univariate analysis revealed 9 variables predicting early death. Subsequent multivariate analysis identified high donor body mass index (BMI; a possible surrogate marker for hepatic steatosis) as the most important predictor of early death (

P

= .009; odds ratio, 1.2; 95% confidence interval, 1.0-1.3). Recipient age >50 (

P

= .015; odds ratio, 4.2; 95% confidence interval, 1.3-14.1) and non-Caucasian recipient ethnicity (

P

= .015; odds ratio, 4.9; 95% confidence interval, 1.2-19.2) were other variables associated with early death on multivariate analysis. This study specifically examined factors that determine the early outcome of transplanted seronegative ALF patients. In conclusion, we found that donor and recipient factors identify patients who have a high chance of early death after transplantation.
A Critical Review of the Health-Related Quality of Life of Children and Adolescents After Liver Transplantation
Authors: Taylor Rachel , Franck Linda S. , Gibson Faith , Dhawan Anil
Published: December 2004

We critically examined research on health-related quality of life (HRQL) in children and adolescents after liver transplantation. The specific aims were to identify research studies on HRQL after liver transplantation, to critique the methodological quality of the studies, to estimate overall HRQL after transplant, and to make recommendations for future research. Databases searched included Medline, Cumulative Index to Nursing and the Allied Health Literature, PsycINFO, EMBASE, Allied and Complementary Medicine, Institute for Scientific Information Web of Science, and Applied Social Sciences Index and Abstracts. Searches also were made on related Web sites and proceedings of transplantation and associated conferences. Eligible studies involved children between birth and 18 years of age who received isolated orthotopic, auxiliary, or living related liver transplantation. HRQL was assessed through 2 or more of the domains of physical health, psychological functioning, social functioning, family functioning, or general well-being. Eligible studies were abstracted, assessed for methodological quality, and synthesized using the sign test to provide an indication of the effect of liver transplantation on each HRQL domain. The synthesis of findings suggested an improvement in HRQL in comparison with pretransplant status; there was a trend toward a worse HRQL in comparison with the healthy population and better than those with other chronic illnesses. In conclusion, liver transplantation in childhood has a negative impact on some aspects of HRQL. However, this finding is tentative because of the small number of studies and variable study quality found.
Calibration of gradient propagation delays for accurate two‐dimensional radiofrequency pulses
Authors: Davies Nigel P. , Jezzard Peter
Published: December 2004

Hardware‐related delays between the requested and actual start times of the gradient waveforms on each physical axis are of particular importance for multidimensional selective excitation in which the synchronization of gradient and radiofrequency (RF) waveforms is critical. A method is proposed for the accurate calibration of gradient propagation delays to optimize the spatial accuracy of 2D RF pulses, although the results may also be used to reduce artifacts in other MR techniques. The sensitivity of 2D RF pulses to uncorrected time shifts between the gradient and RF waveforms was exploited to calibrate accurately the propagation delays on each physical gradient axis. This was achieved using a technique that relates the effect of gradient delays in the component waveforms of a constant‐angular rate spiral k‐space trajectory 2D RF pulse to the spatial location of the subsequent excitation profile. Comparison was also made with a procedure based on a previously described k‐space plotting method, showing broad agreement, but with some discrepancies that illustrate the value of a self‐referenced correction method for multidimensional RF pulses. Magn Reson Med 53:231–236, 2005. © 2004 Wiley‐Liss, Inc.
Analysis and correction of gradient nonlinearity and B0 inhomogeneity related scaling errors in two‐dimensional phase contrast flow measurements
Authors: Peeters Johannes M. , Bos Clemens , Bakker Chris J. G.
Published: December 2004

Phase contrast flow measurements will be increasingly biased at eccentric positions, where nonlinearity of gradients and inhomogeneity of the main field become important. In theory, they scale the result of phase contrast flow values in two ways: incorrect velocity encoding of moving spins and geometric distortion of the vessel cross‐sectional area. A flow phantom, consisting of a 3D grid of interconnected tubes, was used to determine the spatial dependence of the associated scaling factors, which demonstrate that scaling errors in flow can be as large as 20% within the examined volume of 336 × 336 × 336 mm3. The same phantom was also used to determine and minimize concomitant gradient effects. Correction of the off‐center flow values with the local scaling factors and the concomitant gradient phase improves the measurement accuracy substantially, both in the flow phantom and in a volunteer study. Magn Reson Med 53:126–133, 2005. © 2004 Wiley‐Liss, Inc.
Accelerating MR diffusion tensor imaging via filtered reduced‐encoding projection‐reconstruction
Authors: Jiang Yi , Hsu Edward W.
Published: December 2004

MR diffusion tensor imaging (DTI) is a promising tool for characterizing the microstructure of ordered tissues. However, its practical applications are hampered by relatively low signal‐to‐noise‐ratio and spatial and temporal resolution. Reduced‐encoding imaging (REI) via k‐space sharing with constrained reconstruction has previously been shown to be effective for accelerating DTI, although the implementation was based on rectilinear k‐space sampling. Due to the intrinsic oversampling of central k‐space and allowance for isotropic downsampling, projection‐reconstruction (PR) imaging may be better suited for REI. In this study, regularization procedures, including radial filtering and baseline signal correction to adequately reconstruct reduced encoded PR imaging data, are investigated. The proposed filtered reduced‐encoding projection‐reconstruction (FREPR) technique is applied to DTI tissue fiber orientation and fractional anisotropy (FA) measurements. Results show that FREPR offers improved reconstructions of the reduced encoded images and on an equal total scan‐time basis provides more accurate fiber orientation and FA measurements compared to rectilinear k‐space sampling‐based REI methods or a control experiment consisting of only fully encoded images. These findings suggest a potentially significant role of FREPR in accelerating repeated imaging and improving the data acquisition‐time efficiency of DTI experiments. Magn Reson Med 53:93–102, 2005. © 2004 Wiley‐Liss, Inc.
Use of phased array coils for a determination of absolute metabolite concentrations
Authors: Natt Oliver , Bezkorovaynyy Vitaliy , Michaelis Thomas , Frahm Jens
Published: December 2004

This work describes the use of phased array coils for a quantification of absolute metabolite concentrations. The method is demonstrated for single‐voxel localized proton MRS of human brain with an eight‐element receive‐only head coil. It is based on the transmitter reference amplitude of the body coil used for RF transmission. A relative sensitivity of every element of the phased array coil is derived from a combination of two reference scans without water suppression that correspond to either the body coil in transmit‐receive mode or the phased array coil in conjunction with body coil excitation. Experimental results were obtained at 2.9 T for both phantoms and 12 human subjects in different locations of gray and white matter. The data demonstrate that the procedure is technically robust and without a penalty in measuring time. Moreover, it takes full advantage of the signal‐to‐noise gain for quantitative proton MRS and may be extended to other phased array coils without the need for a recalibration. Magn Reson Med 53:3–8, 2005. © 2004 Wiley‐Liss, Inc.
Successful intramuscular neurotization is dependent on the denervation period. A histomorphological study of the gracilis muscle in rats
Authors: Keilhoff Gerburg , Fansa Hisham
Published: December 2004

To characterize the extent to which reinnervation potential depends on the duration of denervation, intramuscular neurotization of the gracilis muscle was performed either immediately or 2, 4, 6, and 8 weeks after transection of the obturator nerve. For neurotization, the sciatic nerve was split into three fascicle groups and fixed intramuscularly. Muscle morphology after 6 weeks of regeneration was identified with anti‐myosin immunohistochemistry and NADH staining. Newly formed motor endplates were characterized using acetylcholinesterase staining and electron microscopy. Wet muscle weight ratio indicated the functional state of synapses. Depending on the denervation period, three levels of regenerative outcome were evident. Best results were seen after immediate neurotization or after 2 weeks of denervation. Regeneration, although at a significantly lower level, also occurred after denervation periods of 4 and 6 weeks. Regeneration following neurotization after 8 weeks of denervation was negligible. Quantity and quality of motor endplate formation depended on the denervation period. Thus, in special clinical situations intramuscular neurotization within a distinct time window provides a good reconstructive option. Muscle Nerve, 2005
Motor evoked potentials (MEP) and evoked pressure curves (EPC) from the urethral compressive musculature (UCM) by functional magnetic stimulation in healthy volunteers and patients with neurogenic incontinence
Authors: Schmid Daniel M. , Curt A. , Hauri D. , Schurch B.
Published: December 2004

Aims

The aim of this study is to assess neurogenic lesions of the somatomotor efferent nervous pathway to the urethral compressive musculature (UCM) by means of motor evoked potentials (MEP) and simultaneously recorded evoked pressure curves (EPC).

Methods

Nine healthy subjects and 33 patients (15 spinal cord injury, 14 cauda equina lesion, and 4 multiple sclerosis (MS)) with neurogenic urinary incontinence were prospectively examined by means of urodynamics and electrophysiology. MEP responses from the UCM were evoked after transcranial (tc) and lumbosacral (ls) single pulse magnetic stimulation. A ratio out of tc/ls latencies was calculated to distinguish between central (i.e., spinal) and peripheral lesions. The mechanical UCM pressure responses ( = EPC) were recorded simultaneously with electromyographic (EMG) recordings using a microtip pressure transducer catheter with integrated bipolar surface electrodes.

Results

In nine healthy subjects the central latency was 19.0 msec, the peripheral latency was 4.25 msec, and the ratio was 4.4. In patients with incomplete spinal cord lesion the central latency was significantly delayed (22.7 msec), whereas the peripheral latency was normal. The ratio (5.5) was increased. Thirteen of these 15 patients suffered from neurogenic incontinence. Patients with a complete spinal lesion showed no UCM reaction after tc stimulation, whereas peripheral responses were normal. Patients with MS showed significantly prolonged central latencies (25.5 msec). The increased ratio of 6.0 indicated a spinal lesion. Ten patients with incomplete cauda equina lesions and urinary incontinence had normal central latencies but prolonged peripheral latencies of 6.7 msec. The ratio of 3.4 indicated a lesion of the sacral caudal roots. In patients with complete cauda injury neither central nor peripheral responses could be evoked. Tc evoked mechanical pressure responses (i.e., contractions) from the UCM could only be recorded in intact or incompletely injured spinal and peripheral motor nervous pathways, whereas they could be evoked after ls stimulation only in cases with partially preserved sacral caudal roots independent of a spinal lesion.

Conclusions

MEP and EPC from the UCM proved to be a well tolerated diagnostic tool in patients with neurogenic incontinence that distinguished central and peripheral lesions of the motor efferent pathways to the UCM. © 2004 Wiley‐Liss, Inc.
A high‐fidelity numerical method for the simulation of compressible flows in cylindrical geometries
Authors: Keiderling F. , Müller S. B. , Kleiser L.
Published: December 2004

A wide range of flows of practical interest occur in cylindrical geometries. In order to simulate such flows, an available compact finite‐difference simulation code [1] was adapted by introducing a mapping that expresses cylindrical coordinates as generalized coordinates. This formulation is conservative and avoids problems associated with the classical formulation of the Navier‐Stokes equations in cylindrical coordinates. The coordinate singularity treatment follows [2] and is modified for generalized coordinates. To retain high‐order numerical accuracy, a Fourier spectral method is employed in the azimuthal direction combined with mode clipping to alleviate time‐step restrictions due to a very fine grid spacing near the singularity at the axis (r = 0). An implementation of this scheme was successfully validated by a simulation of a tripolar vortex formation and by comparison with linear stability theory. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Partial Differential Algebraic Dynamic Model of a Molten Carbonate Fuel Cell
Authors: Sternberg Kati , Chudej Kurt , Pesch Hans Josef
Published: December 2004

Fuel cells convert chemical energy of hydrogen directly into electrical energy providing a clean and highly efficient source of electricity. In this paper we present a partial differential algebraic equation model that describes the gas flow, temperature and electrical potential depending on the reaction kinetics in a molten carbonate fuel cell.

Furthermore we will present results for the numerical simulation of this time dependent two dimensional model. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Categorical View to Structural Complexity
Authors: Aparecida dos Santos Leal Liara , Moraes Claudio Dalcidio , Vieira Toscani Laira
Published: December 2004

In the present work we are interested in to provide a universal language for supporting formalisms to specify the approximation hierarchy system for an abstract NP‐hard optimization problem. This work grew from the idea of providing a categorical view of structural complexity to optimization problems. The direction is aimed towards actually exploring the connections among the structural complexity aspects and categorical concepts, which may be viewed in a high‐level, in a structuralistic sense. After introducing the optimization problems categories OPTS and OPT, as well as related questions, a formal system modelling the approximation hierarchy of a given optimization problem is provided, based on categorical shape theory. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of Aeroelastic Instabilities for Systems with Random Parameters
Authors: Löhr Michael , Dinkler Dieter
Published: December 2004

This paper presents a method for the numerical investigation of aeroelastic systems considering random properties of aerodynamic forces. The numerical analysis of aeroelastic instabilities is based on an eigenvalue problem with random coefficients, thus enabling the analysis of the random characteristics of critical wind velocities, respectively. The aerodynamic coefficients are treated as normally distributed random variables. An expansion in terms of a polynomial chaos scheme is applied in order to describe the statistical properties of the critical wind velocities. Hence, the reliability of structures against aeroelastic vibration phenomena can be estimated. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A decomposition approach for optimal control problems with integer innerpoint state constraints
Authors: Glocker Markus
Published: December 2004

A large class of optimal control problems for hybrid dynamic systems can be formulated as mixed‐integer optimal control problems (MIOCPs). A decomposition approach is suggested to solve a special subclass of MIOCPs with mixed integer inner point state constraints. It is the intrinsic combinatorial complexity of the discrete variables in addition to the high nonlinearity of the continuous optimal control problem that forms the challenges in the theoretical and numerical solution of MIOCPs.

During the solution procedure the problem is decomposed at the inner time points into a multiphase problem with mixed integer boundary constraints and phase transitions at unknown switching points. Due to a discretization of the state space at the switching points the problem can be decoupled into a family of continuous optimal control problems (OCPs) and a problem similar to the asymmetric group traveling salesman problem (AGTSP).

The OCPs are transcribed by direct collocation to large‐scale nonlinear programming problems, which are solved efficiently by an advanced SQP method. The results are used as weights for the edges of the graph of the corresponding TSP‐like problem, which is solved by a Branch‐and‐Cut‐and‐Price (BCP) algorithm.

The proposed approach is applied to a hybrid optimal control benchmark problem for a motorized traveling salesman. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Two Phase Mixture Model based on Bone Observation
Authors: Kühn R.‐R. , Hauger W. , Staat M. , Sponagel S.
Published: December 2004

An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff's law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanical properties of phenolic composites reinforced with jute/cotton hybrid fabrics
Authors: de Medeiros Eliton S. , Agnelli José A. M. , Joseph Kuruvilla , de Carvalho Laura H. , Mattoso Luiz H.C.
Published: December 2004

Mechanical properties (tensile, flexural, impact, and dynamic mechanical thermal analysis) of novolac type phenolic composites reinforced with jute/cotton hybrid woven fabrics were investigated as a function of fiber orientation and roving/fabric characteristics. Scanning electron microscopy (SEM) was carried out to investigate the fiber‐matrix adhesion. Results showed that the composite properties are strongly influenced by test direction and rovings/fabric characteristics. The anisotropy degree was shown to increase with test angle and to strongly depend on the type/architecture of fabric used, i.e., jute rovings diameter, relative fiber content, etc. It was possible to obtain composites with higher mechanical properties and lower anisotropy degree by producing cross‐ply laminates. Best overall mechanical properties were obtained for the composites tested along the jute rovings direction. Composites tested at 45° and 90° with respect to the jute roving direction exhibited a controlled brittle failure combined with a successive fiber pullout, while those tested in the longitudinal direction (0°) exhibited a catastrophic failure mode. Our results indicate that jute promotes a higher reinforcing effect and cotton avoids catastrophic failure. Therefore, this combination of natural fibers is suitable to product composites for lightweight structural applications. POLYM. COMPOS., 26:1–11, 2005. © 2004 Society of Plastics Engineers.
The electrical behavior of thermosetting polymer composites containing metal plated ceramic filler
Authors: Bar Hedva , Narkis Moshe , Boiteux Gisele
Published: December 2004

This paper describes the electrical behavior of a thermosetting system, based on epoxy resin, containing metal plated fillers. Ceramic fillers such as chopped glass fibers and mica flakes were coated with copper by electroless plating and incorporated into an epoxy resin based on di‐glycidyl ether of bisphenol A (DGEBA) with tri‐ethylenetetramine (TETA) curing agent. The percolation threshold in these systems is obtained at very low copper contents of 0.11–0.44 vol%. The epoxy/copper coated mica system is characterized by an extremely large positive temperature coefficient (PTC) effect, which is not followed by a negative temperature coefficient (NTC) effect. Increasing the copper coated mica concentration raises the PTC temperature of the first temperature cycle, and exposing the material to continuous heating‐cooling cycles results in a decrease in the PTC temperature and an increase of its room temperature resistivity. Inverse relations were found between the coefficient of thermal expansion and the PTC temperature. Accordingly, the mechanism governing the PTC effect in the epoxy/copper coated mica composite is based on a larger thermal expansion coefficient of the matrix compared with the ceramic filler. POLYM. COMPOS., 26:12–19, 2005. © 2004 Society of Plastics Engineers.
The fetal circulation
Authors: Kiserud Torvid , Acharya Ganesh
Published: December 2004

Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow. Copyright © 2004 John Wiley & Sons, Ltd.
18O‐labeling quantitative proteomics using an ion trap mass spectrometer
Authors: Sakai Jun , Kojima Shinich , Yanagi Kazunori , Kanaoka Masaharu
Published: December 2004

We describe a method for simultaneous identification and quantitation of proteins within complex mixtures. The method consists of 18O‐labeling, a simple stable isotope‐coding that requires merely enzymatic digestion in 18O‐water, in combination with a capillary‐liquid chromatography electrospray ion‐trap mass spectrometer. In a separate experiment using the same sample and a spike test, we demonstrate that the difference ratio was calculated accurately using the 18O‐labeling method even if the protein was part of a complex mixture. Our data also suggest that the accuracy of the quantitation can be improved by averaging the difference ratios of several peptides. In comparing our method with the isotope‐coded affinity tag (ICAT) method, we show that the 18O‐labeling method has the advantages of better recovery and fewer isotope effects. Therefore, the 18O‐labeling method is a powerful tool for large‐scale proteomics applications.
PRIME: A graphical interface for integrating genomic/proteomic databases
Authors: Facius Axel , Englbrecht Claudia , Birzele Fabian , Groscurth Andreas , Schmid Benjamin , Wanka Steffi , Mewes Werner
Published: December 2004

Data mining, finding and integration of information about proteins of interest, is an essential component in modern biological and biomedical research. Even when focusing on a single organism and on only a small number of proteins, there are often dozens of data sources containing relevant information. We are developing PRIME, a protein information environment, to serve as a virtual central database which integrates distributed heterogeneous information about proteins (linked by a common identifier). PRIME has powerful capabilities to visualize all kinds of protein annotation in specialized views. These views can be displayed side by side at the same time and can be synchronized in order to show simultaneously different aspects of identical proteins. These features allow a quick and comprehensive overview of properties of single proteins or protein sets.
The impact of blood contamination on the proteome of cerebrospinal fluid
Authors: You Jin‐Sam , Gelfanova Valentina , Knierman Michael D. , Witzmann Frank A. , Wang Mu , Hale John E.
Published: December 2004

Human cerebrospinal fluid (CSF) is in direct contact with the brain extracellular space. Beside the secretion of CSF by the choroid plexus the fluid also derives directly from the brain by the ependymal lining of the ventricular system and the glial membrane and from blood vessels in the arachnoid. Therefore, biochemical changes in the brain may be reflected in the CSF. CSF is a potential source of protein molecular indices of central nervous system function and pathology. However, various amounts of blood contamination in CSF may arise during sample acquisition. The concentration of protein in the CSF is only 0.2 to 0.5% that of blood. Minor contamination of CSF with blood during collection of the fluid may dramatically alter the protein profile confounding the identification of potential biomarkers. We have analyzed CSF and CSF spiked with increasing amounts of whole blood using proteomic techniques. We detected at least four blood specific highly abundant proteins: hemoglobin, catalase, peroxiredoxin and carbonic anhydrase I. These proteins can be used as blood contamination markers for proteomic analysis of CSF. Proteins in blood contaminated CSF samples were less stable compared to neat CSF at 37°C suggesting that blood borne proteases may induce protein degradation in CSF during sample acquisition. This analysis was aimed at identification of proteins found primarily in CSF, those found primarily in blood and assessment of the impact of blood contamination on those proteins found in both fluids.
NdPASA: A novel pairwise protein sequence alignment algorithm that incorporates neighbor‐dependent amino acid propensities
Authors: Wang Junwen , Feng Jin‐An
Published: December 2004

Sequence alignment has become one of the essential bioinformatics tools in biomedical research. Existing sequence alignment methods can produce reliable alignments for homologous proteins sharing a high percentage of sequence identity. The performance of these methods deteriorates sharply for the sequence pairs sharing less than 25% sequence identity. We report here a new method, NdPASA, for pairwise sequence alignment. This method employs neighbor‐dependent propensities of amino acids as a unique parameter for alignment. The values of neighbor‐dependent propensity measure the preference of an amino acid pair adopting a particular secondary structure conformation. NdPASA optimizes alignment by evaluating the likelihood of a residue pair in the query sequence matching against a corresponding residue pair adopting a particular secondary structure in the template sequence. Using superpositions of homologous proteins derived from the PSI‐BLAST analysis and the Structural Classification of Proteins (SCOP) classification of a nonredundant Protein Data Bank (PDB) database as a gold standard, we show that NdPASA has improved pairwise alignment. Statistical analyses of the performance of NdPASA indicate that the introduction of sequence patterns of secondary structure derived from neighbor‐dependent sequence analysis clearly improves alignment performance for sequence pairs sharing less than 20% sequence identity. For sequence pairs sharing 13–21% sequence identity, NdPASA improves the accuracy of alignment over the conventional global alignment (GA) algorithm using the BLOSUM62 by an average of 8.6%. NdPASA is most effective for aligning query sequences with template sequences whose structure is known. NdPASA can be accessed online at http://astro.temple.edu/∼feng/Servers/BioinformaticServers.htm. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Evolution of mitochondrial uncoupling proteins: novel invertebrate UCP homologues suggest early evolutionary divergence of the UCP family
Authors: Sokolova I.M. , Sokolov E.P.
Published: December 2004

Current hypothesis about the evolution of uncoupling proteins (UCPs) proposed by Hának and Jezek (2001) [FEBS Lett. 495, 137–141] suggests that UCP4 is the earliest form of UCP ancestral to all other UCP orthologues. However, this hypothesis is difficult to reconcile with a narrow tissue distribution of UCP4 (which is a brain‐specific isoform), suggesting highly specialized rather than anfcestral function for this protein. We searched for UCP2, UCP3, and UCP5 homologues in invertebrate genomes using amplification with degenerate primers designed against UCP2‐specific conserved sequences and/or BLASTP search with stringent ad hoc criteria to distinguish between homologues and orthologues of different UCPs. Our study identified invertebrate UCP homologues similar to UCP2 and 3 (which we termed UCP6) and an invertebrate homologue of UCP5. Phylogenetic analysis indicates that there are at least three clades of UCPs in invertebrates, which are closely related to vertebrate UCP1‐3, UCP4, and UCP5, respectively, and shows early evolutionary divergence of UCPs, which pre‐dates the divergence of protostomes and deuterostomes. It also suggests that the newly identified UCP6 proteins from invertebrates are ancestral to the vertebrate UCP1, UCP2, and UCP3, and that divergence of these three vertebrate orthologues occurred late in evolution of the vertebrates. This study refutes the hypothesis of Hának and Jezek (2001) that UCP4 is an ancestral form for all UCPs, and shows early evolutionary diversification of this protein family, which corresponds to their proposed functional diversity in regulation of proton leak, antioxidant defense and apoptosis.
Thermodynamic and EPR studies of slowly relaxing ubisemiquinone species in the isolated bovine heart complex I
Authors: Ohnishi Tomoko , Johnson Jerry E. , Yano Takahiro , LoBrutto Russell , Widger William R.
Published: December 2004

Previously, we investigated ubisemiquinone (SQ) EPR spectra associated with NADH‐ubiquinone oxidoreductase (complex I) in the tightly coupled bovine heart submitochondrial particles (SMP). Based upon their widely differing spin relaxation rate, we distinguished SQ spectra arising from three distinct SQ species, namely SQNf (fast), SQNs (slow), and SQNx (very slow). The SQNf signal was observed only in the presence of the proton electrochemical gradient , while SQNs and SQNx species did not require the presence of . We have now succeeded in characterizing the redox and EPR properties of SQ species in the isolated bovine heart complex I. The potentiometric redox titration of the g

z,y,x

= 2.00 semiquinone signal gave the redox midpoint potential (E
m) at pH 7.8 for the first electron transfer step [E
m1(Q/SQ)] of −45 mV and the second step [E
m2(SQ/QH2)] of −63 mV. It can also be expressed as [E
m(Q/QH2)] of −54 mV for the overall two electron transfer with a stability constant (K
stab) of the SQ form as 2.0. These characteristics revealed the existence of a thermodynamically stable intermediate redox state, which allows this protein‐associated quinone to function as a converter between n
= 1 and n
= 2 electron transfer steps. The EPR spectrum of the SQ species in complex I exhibits a Gaussian‐type spectrum with the peak‐to‐peak line width of ∼6.1 G at the sample temperature of 173 K. This indicates that the SQ species is in an anionic Q
▪− state in the physiological pH range. The spin relaxation rate of the SQ species in isolated complex I is much slower than the SQ counterparts in the complex I in situ in SMP. We tentatively assigned slow relaxing anionic SQ species as SQNs, based on the monophasic power saturation profile and several fold increase of its spin relaxation rate in the presence of reduced cluster N2. The current study also suggests that the very slowly relaxing SQNx species may not be an intrinsic complex I component. The functional role of SQNs is further discussed in connection with the SQNf species defined in SMP in situ.
The biosynthetic routes for carbon monoxide and cyanide in the Ni–Fe active site of hydrogenases are different
Authors: Roseboom Winfried , Blokesch Melanie , Böck August , Albracht Simon P.J.
Published: December 2004

The incorporation of carbon into the carbon monoxide and cyanide ligands of [NiFe]‐hydrogenases has been investigated by using 13C labelling in infrared studies of the Allochromatium vinosum enzyme and by 14C labelling experiments with overproduced Hyp proteins from Escherichia coli. The results suggest that the biosynthetic routes of the carbon monoxide and cyanide ligands in [NiFe]‐hydrogenases are different.
Modes of remodeling in the cortical cytoskeleton of vascular endothelial cells
Authors: Pesen Devrim , Hoh Jan H.
Published: December 2004

The cortical cytoskeleton of vascular endothelial cells plays an important role in responding to mechanical stimuli and controlling the distribution of cell surface proteins. Here, we have used atomic force microscopy to visualize the dynamics of cortical cytoskeleton in living bovine pulmonary artery endothelial cells. We demonstrate that the cortical cytoskeleton, organized as a complex polygonal mesh, is highly dynamic and shows two modes of remodeling: intact‐boundary‐mode where mesh element boundaries remain intact but move at ∼0.08 μm/min allowing the mesh element to change shape, and altered‐boundary‐mode where new mesh boundaries form and existing ones disappear.
A role for the non‐phosphorylated form of yeast Snf1: tolerance to toxic cations and activation of potassium transport
Authors: Portillo Francisco , Mulet José M. , Serrano Ramón
Published: December 2004

The Snf1/AMP‐activated protein kinases play a key role in stress responses of eukaryotic cells. In the yeast Saccharomyces cerevisiae Snf1 is regulated by glucose depletion, which triggers its phosphorylation at Thr210 and concomitant increase in activity. Activated yeast Snf1 is required for the metabolic changes allowing starvation tolerance and utilization of alternative carbon sources. We now report a function for the non‐activated form of Snf1: the regulation of the Trk high‐affinity potassium transporter, encoded by the TRK1 and TRK2 genes. A snf1Δ strain is hypersensitive in high‐glucose medium to different toxic cations, suggesting a hyperpolarization of the plasma membrane driving increased cation uptake. This phenotype is suppressed by the TRK1 and HAL5 genes in high‐copy number consistent with a defect in K+ uptake mediated by the Trk system. Accordingly, Rb+ uptake and intracellular K+ measurements indicate that snf1Δ is unable to fully activate K+ import. Genetic analysis suggests that the weak kinase activity of the non‐phosphorylated form of Snf1 activates Trk in glucose‐metabolizing yeast cells. The effect of Snf1 on Trk is probably indirect and could be mediated by the Sip4 transcriptional activator.
RETRACTED: Contribution of the PI3K/Akt/PKB signal pathway to maintenance of self‐renewal in human embryonic stem cells
Authors: Kim Sun Jong , Cheon Seon Hye , Yoo Seung Jun , Kwon Jinie , Park Jong Hyuk , Kim Chul Geun , Rhee KunSoo , You Seungkwon , Lee Joo-Yong , Roh Sung Il , Yoon Hyun Soo
Published: December 2004

Reason: upon re‐examination of their work, the authors have found that the data in Figure 2A was intentionally fabricated (the blots of the 3rd and 4th rows are duplicated and are mirror images). As a result, the authors have elected to withdraw the complete article with apologies to the scientific community.
In vivo three‐dimensional wrist motion analysis using magnetic resonance imaging and volume‐based registration
Authors: Goto Akira , Moritomo Hisao , Murase Tsuyoshi , Oka Kunihiro , Sugamoto Kazuomi , Arimura Takehiro , Masumoto Jun , Tamura Shinichi , Yoshikawa Hideki , Ochi Takahiro
Published: December 2004

This study represents a new attempt to non‐invasively analyze three‐dimensional motions of the wrist in vivo. A volume‐based registration method using magnetic resonance imaging (MRI) was developed to avoid radiation exposure. The primary aim was to evaluate the accuracy of volume‐based registration and compare it with surface‐based registration. The secondary aim was to evaluate contributions of the scaphoid and lunate to global wrist motion during flexion‐extension motion (FEM), radio‐ulnar deviation (RUD) and radial‐extension/ulnoflexion, “dart‐throwing” motion (DTM) in the right wrists of 12 healthy volunteers. Volume‐based registration displayed a mean rotation error of 1.29° ± 1.03° and a mean translation error of 0.21 ± 0.25mm and was significantly more accurate than surface‐based registration in rotation. Different patterns of contribution of the scaphoid and lunate were identified for FEM, RUD, and DTM. The scaphoid contributes predominantly in the radiocarpal joint during FEM, in the midcarpal joint during RUD and almost equally between these joints during DTM. The lunate contributes almost equally in both joints during FEM and predominantly in the midcarpal joint during RUD and DTM. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Evolution of an in vivo bioreactor
Authors: Holt Ginger E. , Halpern Jennifer L. , Dovan Thomas T. , Hamming David , Schwartz Herbert S.
Published: December 2004

The ideal bone graft substitute requires osteoconductive, osteoinductive, and osteogenic components. This study introduces an “in vivo bioreactor,” a model in which pluripotent cells are recruited from circulating blood to a vascularized coralline scaffold supplemented with bone morphogenetic protein‐2 (BMP‐2). The bioreactor generates new, ectopic host bone with the capability of vascularized tissue transfer. More importantly, bone is reproducibly formed in a closed and malleable environment. In a rat model, the superficial inferior epigastric vessels were isolated, ligated, and then threaded through a prefabricated coral cylinder (hydroxyapatite, ProOsteon 500). Experimental groups were characterized by the following variables: (1) with/without incorporation of vascular pedicle; (2) with/without addition of BMP‐2 (0.02 mg/cm3). Scaffolds were harvested 6 weeks after implantation, embedded and sectioned. Tissue samples were decalcified, fixed, and stained with H&E, trichrome green, and CD31/PECAM‐1 (a marker of endothelial cells). Vascularized coral scaffolds supplemented with BMP‐2 presumably recruited circulating mesenchymal stem cells to generate bone. Bone formation was quantified through histological analysis, and reported as a percentage, area bone/area cross section scaffold × 100. Mean bone formation was 11.30% ± 1.19. All scaffolds supplied by the vascular pedicle, regardless of BMP‐2 supplementation, demonstrated neo‐vascular ingrowth. Scaffolds lacking a pedicle showed no evidence of vascular ingrowth or bone formation. This paper introduces a model of a novel “in vivo bioreactor” that has future clinical and research applications. The tissue engineering applications of the “bioreactor” include treatment of skeletal defects (nonunion, tumor post‐resection reconstruction). The bioreactor also may serve as a unique model in which to study primary and metastatic cancers of bone. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.