bluuebunny/crossref_metadata_2025 huggingface dataset:
Proton MRI of lung parenchyma reflects allergen‐induced airway remodeling and endotoxin‐aroused hyporesponsiveness: A step toward ventilation studies in spontaneously breathing rats
Authors: Beckmann Nicolau , Cannet Catherine , Zurbruegg Stefan , Rudin Markus , Tigani Bruno
Published: July 2004

Proton signals from lung parenchyma were detected with the use of a gradient‐echo sequence to noninvasively obtain information on pulmonary function in models of airway diseases in rats. Initial measurements carried out in artificially ventilated control rats revealed a highly significant negative correlation between the parenchymal signal and the partial pressure of oxygen (pO2) in the blood, for different amounts of oxygen administered. The magnitude of the signal intensity variations caused by changes in the oxygen concentration was larger than expected solely from the paramagnetic properties of molecular oxygen. Inhomogeneous line‐broadening induced by lung inflation may explain the observed signal amplification. Experiments carried out in spontaneously breathing animals challenged with allergen or endotoxin revealed parenchymal signal changes that reflected the oxygenation status of the lungs and were consistent with airway remodeling or hyporesponsiveness. The results suggest that proton MRI of parenchymal tissue is a sensitive tool for probing the functional status of the lung in rat models of respiratory diseases. The method is complementary to the recently described noninvasive assessment by MRI of pulmonary inflammation in small rodents. Overall, these techniques provide invaluable information for profiling anti‐inflammatory drugs in models of airway diseases. Magn Reson Med 52:258–268, 2004. © 2004 Wiley‐Liss, Inc.
Effects of physiologic challenge on the ADC of intracellular water in the Xenopus oocyte
Authors: Sehy Jonathan V. , Zhao Lin , Xu Junqian , Rayala Heidi J. , Ackerman Joseph J.H. , Neil Jeffrey J.
Published: July 2004

The biophysical determinants of the intracellular water apparent diffusion coefficient (ADC) in mammalian tissues are poorly understood. Model systems that are more amenable to physical measurements may provide insights into the behavior of more complex systems. Toward that end, we used MRI to evaluate the effects of altered microtubule concentration, nuclear breakdown, and ATP depletion on intracellular water ADC in the Xenopus oocyte. Water ADC did not change in response to polymerization of microtubules with taxol or depolymerization with nocodazole. Water ADC did not change following the breakdown of the nucleus in healthy cells. Short‐term depletion of ATP (∼20% of normal levels following 4 hr of exposure to sodium azide and 2‐deoxy‐D‐glucose) was not associated with a change in intracellular ADC. Long‐term depletion of ATP (∼20% of normal levels following 2 days of exposure to antimycin A) was associated with a significant decrease in intracellular water ADC. These findings suggest that intracellular water diffusion in oocytes is not dependent on the state of microtubule polymerization or short‐term ATP depletion, although long‐term ATP depletion is associated with changes that lead to a decrease in intracellular water ADC. Magn Reson Med 52:239–247, 2004. © 2004 Wiley‐Liss, Inc.
Development of a compact MRI system for trabecular bone volume fraction measurements
Authors: Kose Katsumi , Matsuda Yoshimasa , Kurimoto Takeaki , Hashimoto Seitarou , Yamazaki Yukako , Haishi Tomoyuki , Utsuzawa Shin , Yoshioka Hiroshi , Okada Shigemasu , Aoki Masaaki , Tsuzaki Tsuyoshi
Published: July 2004

A compact MRI system for measuring trabecular bone volume fraction (TBVF) of the calcaneus was developed with the use of a 0.21 T permanent magnet and portable MRI console. The entire system weighed < 600 kg and was installed in a 2 m × 2 m space. Two cross‐sectional spin‐echo images of a heel acquired with external reference phantoms (total measurement time = 5 min) were used to quantify the TBVF of the calcaneus. The linearity and reproducibility of the measurements were evaluated by means of proton density‐adjusted phantoms. Comparative measurements with quantitative ultrasound (QUS) in groups of healthy female volunteers showed a relatively high positive correlation (R2 = 0.4539, 0.2693) between TBVF and the speed of sound (SOS). These results demonstrate the potential of this new system for measuring bone density. Magn Reson Med 52:440–444, 2004. © 2004 Wiley‐Liss, Inc.
Histochemical detection of ultrasmall superparamagnetic iron oxide (USPIO) contrast medium uptake in experimental brain ischemia
Authors: Schroeter Michael , Saleh Andreas , Wiedermann Dirk , Hoehn Mathias , Jander Sebastian
Published: July 2004

Recently, macrophage infiltration in different central nervous system (CNS) pathologies has been visualized with ultrasmall particles of iron oxide (USPIO) as a new cell‐specific contrast medium for MRI. However, validation of these findings at the histological level has been hampered by the fact that the in situ detection of iron uptake by conventional Prussian blue staining is not sensitive enough to detect low amounts of iron in the brain. Here, an improved method for the histochemical detection of USPIO uptake in ischemic brain lesions is reported. The procedure relies on the sequential enhancement of Prussian blue staining by diaminobenzidine and silver/gold impregnation. After photothrombotic cortical brain infarction, this method allowed sensitive in situ detection of iron‐laden macrophages which matched both macrophage immunostaining and USPIO‐induced signal alterations in high‐resolution 7 T MRI. This staining method provides a basis for correlative histological assessment of USPIO‐enhanced MRI in a broad spectrum of CNS pathologies. Magn Reson Med 52:403–406, 2004. © 2004 Wiley‐Liss, Inc.
Imaging oxygen consumption in forepaw somatosensory stimulation in rats under isoflurane anesthesia
Authors: Liu Zhaohui M. , Schmidt Karl F. , Sicard Kenneth M. , Duong Timothy Q.
Published: July 2004

The cerebral metabolic rate of oxygen (CMRO2) was dynamically evaluated on a pixel‐by‐pixel basis in isoflurane‐anesthetized and spontaneously breathing rats following graded electrical somatosensory forepaw stimulations (4, 6, and 8mA). In contrast to α‐chloralose, which is the most widely used anesthetic in forepaw‐stimulation fMRI studies of rats under mechanical ventilation, isoflurane (1.1–1.2%) provided a stable anesthesia level over a prolonged period, without the need to adjust the ventilation volume/rate or sample blood gases. Combined cerebral blood flow signals (CBF) and blood oxygenation level‐dependent (BOLD) fMRI signals were simultaneously measured with the use of a multislice continuous arterial spin labeling (CASL) technique (two‐coil setup). CMRO2 was calculated using the biophysical BOLD model of Ogawa et al. (Proc Natl Acad Sci USA 1992;89:5951–5955). The stimulus‐evoked BOLD percent changes at 4, 6, and 8mA were, respectively, 0.5% ± 0.2%, 1.4% ± 0.3%, and 2.0% ± 0.3% (mean ± SD, N = 6). The CBF percent changes were 23% ± 6%, 58% ± 9%, and 87% ± 14%. The CMRO2 percent changes were 14% ± 4%, 24% ± 6%, and 43% ± 11%. BOLD, CBF, and CMRO2 activations were localized to the forepaw somatosensory cortices without evidence of plateau for oxygen consumption, indicative of partial coupling of CBF and CMRO2. This study describes a useful forepaw‐stimulation model for fMRI, and demonstrate that CMRO2 changes can be dynamically imaged on a pixel‐by‐pixel basis in a single setting with high spatiotemporal resolution. Magn Reson Med 52:277–285, 2004. © 2004 Wiley‐Liss, Inc.
Metabolite and diffusion changes in the rat brain after Leksell Gamma Knife irradiation
Authors: Herynek Vít , Burian Martin , Jirák Daniel , Liščák Roman , Náměstková Kateřina , Hájek Milan , Syková Eva
Published: July 2004

Our study describes the time course of necrotic damage to the rat brain resulting from Leksell Gamma Knife (LGK) irradiation at a dose that was previously considered to be subnecrotic. A lesion induced in the rat hippocampus by 35 Gy irradiation was monitored by MRI, MRS, and DW‐MRI for 16 months. T2‐weighted images revealed a large hyperintense area with an increased apparent diffusion coefficient of water (ADCw), which occurred 8 months after irradiation, accompanied by metabolic changes (increase of lactate (Lac) and choline (Cho), and decrease of creatine (Cr) and N‐acetyl aspartate (NAA), as determined by MRS) that indicated an edema. In two animals, the hyperintensity persisted and a postnecrotic cavity connected to enlarged lateral ventricles developed. In the rest of the animals, the hyperintensity started to decrease 9 months post‐irradiation (PI), revealing hypointense areas with a decreased ADCw. Histology confirmed the MRI data, showing either scar formation or the development of a postnecrotic cavity. Magn Reson Med 52:397–402, 2004. © 2004 Wiley‐Liss, Inc.
Factors affecting the accuracy of pressure measurements in vascular stenoses from phase‐contrast MRI
Authors: Nasiraei‐Moghaddam Abbas , Behrens Geoffrey , Fatouraee Nasser , Agarwal Ramesh , Choi Eric T. , Amini Amir A.
Published: July 2004

In this work the effects of noise, resolution, and velocity (flow) on the measurement of intravascular pressure from phase‐contrast (PC) MRI are discussed. To elucidate these effects, we employed an axisymmetric geometry that enabled us to calculate pressures in <2 min on a Sun Ultra SPARC 10 workstation. To determine the effects of vascular stenoses, we fabricated several stenotic phantom geometries (with 50%, 75%, and 90% area stenoses), and performed both MRI and computational fluid dynamics (CFD) simulations for various flow rates for these phantom geometries. Noise with Gaussian statistics was added to the velocity field obtained from the CFD simulations. The pressure maps obtained directly from CFD simulations for our phantom geometries were compared with pressure maps derived by our algorithm when 1) the input was noise‐corrupted velocity data from CFD, and 2) the input was PC‐MRI data collected from the phantoms. The quantitative effects of noise, resolution, and flow rate on the accuracy of pressure measurements were determined. We found that for flow rates below the Reynolds number for turbulent flow, resolution is a more significant determinant of accuracy than SNR. Furthermore, if other parameters remain constant, increased flow rates may result in decreased accuracy. Magn Reson Med 52:300–309, 2004. © 2004 Wiley‐Liss, Inc.
Contribution of oxygenation to BOLD contrast in exercising muscle
Authors: Jordan Bénédicte F. , Kimpalou José Zéfu , Beghein Nelson , Dessy Chantal , Feron Olivier , Gallez Bernard
Published: July 2004

The potential physiological and therapeutic applications of functional MRI (fMRI) in skeletal muscle will depend on our ability to identify factors that may contribute to fluctuations in the BOLD signal. Until now, interpretations of signal changes in fMRI studies of muscle have mostly relied on the increase in muscle T2 associated with osmotically driven fluid shifts. However, recent studies have documented increases in BOLD signal intensity (SI) after single contractions, coinciding with increases in muscle hemoglobin saturation. In this study, the factors that contribute to variations in the intensity of the BOLD signal in exercising muscle are further addressed. For this purpose, BOLD imaging was performed during and after a moderate electrical stimulation was applied to the sciatic nerve in mice. In addition, oxygen pressure (pO2), blood flow, and skeletal muscle T2 (fast and slow components: T2 and T, respectively) were monitored. A comparison between mice lacking eNOS (eNOS−/− mice) and their wild‐type (WT) littermates was performed. In WT mice, the BOLD SI, as well as muscle oxygenation and T, were significantly increased for a prolonged time in response to this moderate exercise protocol. Blood flow immediately dropped after the electrical stimulation was stopped. In eNOS−/− mice, the high BOLD SI did not persist after the exercise protocol ended. This finding correlates well with the evolution of muscle oxygenation, which progressively decreases after stimulation in eNOS−/− mice. However, T remained high for a prolonged time after stimulation. We therefore concluded that the maintenance of BOLD SI in moderately exercising skeletal muscle depends mainly on changes in pO2, rather than on blood flow or T2 effects. Magn Reson Med 52:391–396, 2004. © 2004 Wiley‐Liss, Inc.
Coherence‐induced artifacts in large‐flip‐angle steady‐state spin‐echo imaging
Authors: Vasilic Branimir , Song Hee Kwon , Wehrli Felix W.
Published: July 2004

High‐resolution imaging of trabecular bone aimed at analyzing the bone's microarchitecture is preferably performed with spin‐echo‐type pulse sequences. Unlike gradient echoes, spin‐echoes are immune to artifactual broadening of trabeculae caused by local static field gradients near the bone–bone marrow interface and signal loss from chemical shift dephasing at k‐space center. However, the previously practiced 3D fast large‐angle spin‐echo (FLASE) pulse sequence was found to be prone to a low‐frequency modulation artifact in both the readout and slice direction. The artifact is caused by deviations in the effective flip angle of the nonselective 180° pulse, which converts a fraction of the phase‐encoded transverse magnetization to longitudinal magnetization. The latter recurs as transverse magnetization in the subsequent pulse sequence cycle forming a spurious stimulated echo. The objective of this work was to perform a k‐space analysis of this steady‐state artifact and propose two modifications of the original 3D FLASE that effectively remove it. The results of the simulations were in exact agreement with the experiments and the proposed remedy was found to eliminate the artifact. Magn Reson Med 52:346–353, 2004. © 2004 Wiley‐Liss, Inc.
Multiprocessor scheduling implementation of the simultaneous multiple volume (SMV) navigator method
Authors: Kolmogorov Vladimir , Nguyen Thanh D. , Nuval Anthony , Spincemaille Pascal , Prince Martin R. , Zabih Ramin , Wang Yi
Published: July 2004

The simultaneous multiple volume (SMV) approach in navigator‐gated MRI allows the use of the whole motion range or the entire scan time for the reconstruction of final images by simultaneously acquiring different image volumes at different motion states. The motion tolerance range for each volume is kept small, thus SMV substantially increases the scan efficiency of navigator methods while maintaining the effectiveness of motion suppression. This article reports a general implementation of the SMV approach using a multiprocessor scheduling algorithm. Each motion state is regarded as a processor and each volume is regarded as a job. An efficient scheduling that completes all jobs in minimal time is maintained even when the motion pattern changes. Initial experiments demonstrated that SMV significantly increased the scan efficiency of navigator‐gated MRI. Magn Reson Med 52:362–367, 2004. © 2004 Wiley‐Liss, Inc.
Fast three‐dimensional k‐space trajectory design using missile guidance ideas
Authors: Mir Roberto , Guesalaga Andres , Spiniak Juan , Guarini Marcelo , Irarrazaval Pablo
Published: July 2004

Three‐dimensional (3D) k‐space trajectories are needed to acquire volumetric images in MRI. While scan time is determined by the trajectory efficiency, image quality and distortions depend on the shape of the trajectories. There are several 3D trajectory strategies for sampling the k‐space using rectilinear or curve schemes. Since there is no evidence about their optimality in terms of image quality and acquisition time, a new design method based on missile guidance ideas is explored. Since air‐to‐air missile guidance shares similar goals and constraints with the problem of k‐space trajectory design, a control approach for missiles is used to design a 3D trajectory. The k‐space is divided into small cubes, and each one is treated as a target to be sampled. The main goal is to cover the entire space as quickly and efficiently as possible, with good performance under different conditions. This novel design method is compared to other trajectories using simulated and real data. As an example, a trajectory that requires 0.11 times the number of shots needed by the cylindrical 3DFT acquisition was designed. This trajectory requires more shots (1.66 times) than the stack of spirals, but behaves better under nonideal conditions, such as off‐resonance and motion. Magn Reson Med 52:329–336, 2004. © 2004 Wiley‐Liss, Inc.
Multiple spin‐echo spectroscopic imaging for rapid quantitative assessment of N‐acetylaspartate and lactate in acute stroke
Authors: Stengel Astrid , Neumann‐Haefelin Tobias , Singer Oliver C. , Neumann‐Haefelin Claudia , Zanella Friedhelm E. , Lanfermann Heinrich , Pilatus Ulrich
Published: July 2004

Monitoring the signal levels of lactate (Lac) and N‐acetylaspartate (NAA) by chemical shift imaging can provide additional knowledge about tissue damage in acute stroke. Despite the need for this metabolic information, spectroscopic imaging (SI) has not been used routinely for acute stroke patients, mainly due to the long acquisition time required. The presented data demonstrate that the application of a fast multiple spin‐echo (MSE) SI sequence can reduce the measurement time to 6 min (four spin echoes per echo train, 32 × 32 matrix). Quantification of Lac and NAA in terms of absolute concentrations (i.e., mmol/l) can be achieved by means of the phantom replacement approach, with correction terms for the longitudinal and transversal relaxation adapted to the multiple spin‐echo sequence. In this pilot study of 10 stroke patients (symptom onset < 24 hr), metabolite concentrations obtained from MSE‐SI add important information regarding tissue viability that is not provided by other sequences (e.g., diffusion‐weighted imaging (DWI) and perfusion‐weighted imaging (PWI)). Metabolic changes extended beyond the borders of the apparent diffusion coefficient (ADC) lesion in nine of the 10 patients, showing a rise in Lac concentrations up to 18 mmol/l, while NAA levels sometimes dropped below the detection level. Considerable differences among the patients in terms of the Lac concentrations and the size of the SI‐ADC mismatch were observed. Magn Reson Med 52:228–238, 2004. © 2004 Wiley‐Liss, Inc.
Off‐resonance effects in the transient response of SSFP sequences
Authors: Ganter Carl
Published: July 2004

A previously developed eigenvector formalism is adapted to off‐resonance in the transient response of quasiperiodic steady‐state free precession (SSFP) sequences, including TrueFISP as a special case. The effective relaxation rates for essentially parallel and perpendicular deviations from the steady state are determined analytically in leading order perturbation theory. The latter are a known cause of oscillatory artifacts and therefore constitute the main target of a variety of preparation techniques. In addition, the former also play a dominating role in applications such as inversion recovery (IR) TrueFISP, which intentionally measure far away from the equilibrium. For both components, the approach toward equilibrium turns out to depend sensitively on field inhomogeneities, especially for smaller ratios of T2/T1. For the perpendicular deviations, the calculations show that—except very close to banding artifacts, where the steady‐state signal is almost zero—field inhomogeneities additionally increase their effective relaxation rate almost as much as in the free induction decay (FID). The analytical results are tested against numerical simulation and MR measurements. Magn Reson Med 52:368–375, 2004. © 2004 Wiley‐Liss, Inc.
Electrodynamics and ultimate SNR in parallel MR imaging
Authors: Wiesinger Florian , Boesiger Peter , Pruessmann Klaas P.
Published: July 2004

The purpose of this article is to elucidate inherent limitations to the performance of parallel MRI. The study focuses on the ultimate signal‐to‐noise ratio (SNR), which refers to the maximum SNR permitted by the electrodynamics of the signal detection process. Using a spherical model object, it is shown that the behavior of the ultimate SNR imposes distinct limits on the acceleration rate in parallel imaging. For low and moderate acceleration, the ultimate SNR performance is nearly optimal, with geometry factors close to 1. However, for high reduction factors beyond a critical value, the ultimate performance deteriorates rapidly, corresponding to exponential growth of the geometry factor. The transition from optimal to deteriorating performance depends on the electrodynamic characteristics of the detected RF fields. In the near‐field regime, i.e., for low B0 and small object size, the critical reduction factor is constant and approximately equal to four for 1D acceleration in the sphere. In the far‐field wave regime the critical reduction factor is larger and increases both with B0 and object size. Therefore, it is concluded that parallel techniques hold particular promise for human MR imaging at very high field. Magn Reson Med 52:376–390, 2004. © 2004 Wiley‐Liss, Inc.
The Brazilian experience with a photovoltaic powered reverse osmosis plant
Authors: de Carvalho Paulo Cesar Marques , Riffel Douglas Bressan , Freire Cristiano , Montenegro Francisco Fabio Damasceno
Published: July 2004

This article describes a system that combines the technologies of reverse osmosis and photovoltaics to realize a pioneer project for drinking water supply to a rural community in semi‐arid Brazil (latitude 3°44′S), with a local yearly average temperature of 28°C and a yearly solar potential of about 2000 kW h m−2. Two strategies are investigated: first the PV‐RO (photovoltaic powered reverse osmosis) plant is equipped with a DC motor; and second, a three‐phase induction motor is used. Through the analysis of the stored data the second option is chosen as the better alternative. This strategy has a specific electrical consumption (energy required to produce 1 m3 drinking water) of 3·03 kW h m−3, a recovery ratio of 27% (relation between drinking water product flow and brackish water input flow) and a drinking water cost of US$ 12·76 per m3. Copyright © 2004 John Wiley & Sons, Ltd.
Light‐modulated lock‐in thermography for photosensitivepn‐structures and solar cells
Authors: Kaes M. , Seren S. , Pernau T. , Hahn G.
Published: July 2004

Lock‐in thermography (LIT) is a well‐established tool for defect analysis of solar cells, but so far has been restricted to the measurement of metallized samples. The new light‐modulated lock‐in thermography (LimoLIT) described in this paper overcomes this restriction by generating the voltage modulation needed for detection from photovoltaic conversion of modulated light. Thus wafers can be measured during all stages of fabrication, apn‐junction provided. The contactless LimoLIT method shows a stronger measurement signal and invokes a current flow close to illuminated operating conditions of solar cells, whereas conventional LIT is only comparable to a darkI–Vmeasurement. Copyright © 2004 John Wiley & Sons, Ltd.
Solar cell efficiency tables (version 24)
Authors: Green Martin A. , Emery Keith , King David L. , Igari Sanekazu , Warta Wilhelm
Published: July 2004

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since January 2004 are reviewed. Copyright © 2004 John Wiley & Sons, Ltd.
Analysis of the humoral immune response to immunoselected phage‐displayed peptides by a microarray‐based method
Authors: Cekaite Lina , Haug Ola , Myklebost Ola , Aldrin Magne , Østenstad Bjørn , Holden Marit , Frigessi Arnoldo , Hovig Eivind , Sioud Mouldy
Published: July 2004

We describe a novel approach for high‐throughput analysis of the immune response in cancer patients using phage‐based microarray technology. The recombinant phages used for fabricating phage arrays were initially selected via the use of random peptide phage libraries and breast cancer patient serum antibodies. The peptides displayed by the phages retained their ability to be recognized by serum antibodies after immobilization. The recombinant phage microarrays were screened against either breast cancer or healthy donor serum antibodies. A model‐based statistical method is proposed to estimate significant differences in serum antibody reactivity between patients and normals. A significant tumor effect was found with most of the selected phage‐displayed peptides, suggesting that recombinant phage microarrays can serve as a tool in monitoring humoral responses towards phage‐displayed peptides.
Proteomic analysis of differential protein expression in neuropathic pain and electroacupuncture treatment models
Authors: Sung Ho Joong , Kim Yoon Suk , Kim In Sik , Jang Sung‐Wuk , Kim Yoon Rim , Na Doe Sun , Han Ki Hoon , Hwang Byung Gil , Park Dong Suk , Ko Jesang
Published: July 2004

Acupuncture has long been used for pain relief. Although recent studies have shown that acupuncture can reduce neuropathic pain, the mechanism of this effect is not clear and little information is available regarding proteins that are involved in the development of neuropathic pain and the effects of acupuncture. We have developed an animal model for neuropathic pain using young adult male Sprague‐Dawley rats. The model was confirmed by behavioral tests. Electroacupuncture (EA) treatment was applied to Zusanli (ST36) of neuropathic pain model to examine the analgesic effect of EA. The protein expression profile of the hypothalamus in both neuropathic pain and EA treatment models was analyzed using two‐dimensional electrophoresis‐based proteomics. We detected thirty‐six proteins that were differentially expressed in the neuropathic pain model compared with normal rats and that restored to normal expression levels after EA treatment. Twenty‐one of these proteins were identified in the MS‐FiT database and are involved in a number of biological processes, including inflammation, enzyme metabolism and signal transduction. Potential applications of our results include the identification and characterization of signaling pathways involved in EA treatment and further exploration of the role of selected identified proteins in the animal model.
Surface‐enhanced laser desorption/ionization‐time of flight‐mass spectrometry approach to biomarker discovery in blue mussels (Mytilus edulis) exposed to polyaromatic hydrocarbons and heavy metals under field conditions
Authors: Knigge Thomas , Monsinjon Tiphaine , Andersen Odd‐Ketil
Published: July 2004

Proteomics provide potential in the discovery of new sensitive biomarkers for environmental pollution. To evaluate this potential, we have utilized ProteinChip® technology to analyze the proteomic profile of blue mussels (Mytilus edulis) from polluted marine habitats surrounding the island of Karmøy, Norway. Two different types of contamination, heavy metals and polyaromatic hydrocarbons (PAHs), were compared to a clean reference site. Differentially expressed proteins/peptides were found, which showed a specific induction or a general suppression associated with the field site of origin. By combining sets of protein markers in a tree‐building algorithm, we were able to correctly classify samples from these sites with an accuracy of 90%.
Two‐dimensional electrophoresis for the isolation of integral membrane proteins and mass spectrometric identification
Authors: Rais Isam , Karas Michael , Schägger Hermann
Published: July 2004

Acrylamide concentration, urea content, and the trailing ion used for sodium dodecyl sulfate (SDS)‐gels modify electrophoretic protein mobilities in a protein‐dependent way. Varying these parameters we coupled two SDS‐gels to a two‐dimensional (2‐D) electrophoresis system. Protein spots in 2‐D gels are dispersed around a diagonal. Hydrophobic proteins are well separated from water‐soluble proteins which is the essential advantage of the novel technique. Mass spectrometric identification of previously unaccessible hydrophobic proteins is now possible.
Initiation of free‐radical polymerization by peroxypivalates studied by electrospray ionization mass spectrometry
Authors: Buback Michael , Frauendorf Holm , Vana Philipp
Published: July 2004

Initiation by tert‐butyl peroxypivalate (TBPP), tert‐amyl peroxypivalate (TAPP), 1,1,3,3‐tetramethylbutyl peroxypivalate (TMBPP), or 1,1,2,2‐tetramethylpropyl peroxypivalate (TMPPP) of radical polymerization of methyl methacrylate in toluene solution at 90 °C was studied via polymer end‐group analysis using electrospray ionization mass spectrometry (ESI‐MS). Conclusive peak assignments allowed for measuring the type and concentration of the fragments that actually initiate macromolecular growth after thermal decomposition of these peroxypivalates. It was found that the pivaloyloxy radical moiety undergoes instantaneous decarboxylation to yield an initiating tert‐butyl radical. The alkoxy radical moiety, on the other hand, may generate, via β‐scission reaction, different types of carbon‐centered radicals (together with a ketone) or may undergo a 1,5‐H‐shift reaction, by which reaction an oxygen‐centered radical is transformed into a carbon‐centered hydroxy radical. This hydrogen shift reaction was found in case of TMBPP. Surprisingly, no evidence for initiating alkoxy radicals could be found, not even in case of initiation by TBPP, where the intermediate tert‐butoxy radical undergoes a rapid chain‐transfer reaction with the solvent toluene. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4266–4275, 2004
Obesity and the risk of prostate cancer
Authors: Porter Michael P. , Stanford Janet L.
Published: July 2004

Background

Prostate cancer and obesity are common diseases among men in the United States. A link between obesity and prostate cancer risk has potential implications in understanding prostate cancer genesis and screening strategies.

Methods

We conducted a population‐based case‐control study examining the relationship between body mass index (BMI) and prostate cancer risk. Incident cases of prostate cancer were identified in King County, Washington, using the Surveillance, Epidemiology, and End Results (SEER) cancer registry. Interviews were completed with 753 men ages 40–64 that were diagnosed with prostate cancer between 1993 and 1996. Interviews were also completed with 703 age‐matched controls identified from the same population through random digit dialing. Logistic regression was performed to generate odds ratios and 95% confidence intervals while controlling for age, race, education, smoking, family history, prostate cancer screening, dietary fat, and caloric intake.

Results

BMI was inversely related to prostate cancer risk (P for trend = 0.04). Men with a BMI > 29 kg/m2 had the lowest risk of prostate cancer (odds ratio = 0.77; 95% confidence interval = 0.56, 1.06). Weight was also inversely associated with prostate cancer risk (P for trend = 0.03), however, height was not.

Conclusions

The results of this study support the hypothesis that obesity is inversely associated with prostate cancer risk in middle‐aged men. © 2004 Wiley‐Liss, Inc.
Expression of Foxa transcription factors in the developing and adult murine prostate
Authors: Mirosevich Janni , Gao Nan , Matusik Robert J.
Published: July 2004

Background

The Foxa family (a1, a2, and a3) of proteins are transcription factors that are central to endodermal development. Recently, Foxa1 has been shown to regulate the transcription of several murine and human prostate specific genes involved in differentiated function by interacting with DNA promoter sequences and androgen receptors. Currently, the developmental expression pattern of Foxa proteins in the murine prostate is unknown.

Methods

Male CD‐1 mice (embryonic, prepubertal, pubertal, and adult) were used for immunohistochemical analysis of Foxa1, a2, and a3. Immunofluorescence was also performed for androgen receptor and cytokeratin 14 expression. Prostate tissue from pre‐pubertal, pubertal, and adult mice were analyzed by Western blot and RT‐PCR analysis for Foxa1, a2, and a3 expression.

Results

Strong Foxa1 immunoreactivity was observed in epithelial cells throughout prostate development, growth, and adult differentiation. Prominent Foxa2 protein expression was only observed in the early stages of prostate development and was exclusively localized to epithelial cells of the forming buds. RT‐PCR analysis identified low Foxa2 mRNA expression levels in the ventral and dorsolateral lobes of the adult prostate, with Foxa2 epithelial cell expression being localized to periurethral regions of the murine adult prostatic complex. Foxa3 expression was not observed in the murine prostate.

Conclusions

Foxa proteins represent epithelial cell markers in the murine prostate gland. The early expression of Foxa1 and a2 proteins in prostate formation suggests that these proteins play an important role in normal prostate development, in addition to differentiated secretory function. © 2004 Wiley‐Liss, Inc.
Histone deacetylase inhibitors differentially mediate apoptosis in prostate cancer cells
Authors: Frønsdal Katrine , Saatcioglu Fahri
Published: July 2004

Background

Histone deacetylase (HDAC) inhibitors have shown significant anti‐proliferative and apoptotic properties on various cancer cells, including prostate cancer, and are therefore being evaluated as treatment modalities. However, the specific effect of HDAC inhibitors on androgen‐sensitive and androgen‐independent cell lines have not been thoroughly studied which we hypothesized could be different. We therefore assessed whether three structurally unrelated HDAC inhibitors, trichostatin A (TSA), depsipeptide (FR901228), and sodium butyrate, affect cell death in the prostate cancer cell lines LNCaP, DU‐145, and PC‐3.

Methods

To investigate the extent and the nature of cell death, we used Trypan blue exclusion assay, phase‐contrast light microscopy, fluorescence microscopy, and Western blot analyses.

Results

At concentrations where they potentiate transcriptional activation, all three HDAC inhibitors induced cell death in LNCaP and DU‐145 cells, but not in PC‐3 cells, within the timeline of the experiments. HDAC inhibitor‐induced cell death in LNCaP and DU‐145 cells showed several characteristic apoptotic features, such as cell shrinkage, nuclear condensation, and poly(ADP) ribose polymerase cleavage. However, there were differences in the way LNCaP and DU‐145 cells responded to treatment with various HDAC inhibitors. For example, whereas TSA and FR901228 were more effective in inducing apoptosis in LNCaP cells compared with DU‐145 cells, the reverse was true for sodium butyrate. Moreover, within the same cell line, TSA, FR901228, and sodium butyrate exhibited different potencies for induction of apoptosis.

Conclusions

Collectively, these results suggest that the response of prostate cancer cells to HDAC inhibitors is not uniform, but cell line and inhibitor specific. Given that prostate cancer is generally a multiclonal disease representing different cell lineages, it is important to develop HDAC inhibitors that will be effective against all of these cell types. © 2004 Wiley‐Liss, Inc.
Constitutive activation of gp130 leads to neuroendocrine differentiation in vitro and in vivo
Authors: Palmer Jodie , Ernst Matthias , Hammacher Annet , Hertzog Paul J.
Published: July 2004

Background

Neuroendocrine (NE) differentiation in prostate tumors has been correlated with androgen independent disease and increased risk of death. In vitro, IL‐6 initiates NE differentiation utilizing the signal transduction initiated by the interaction with IL‐6R alpha and gp130. In this study we analysed the NE differentiation process in vitro and in vivo using the LNCaP androgen dependent cell line via ligand independent induction of NE differentiation.

Methods

LNCaP cells were transfected with a constitutively active gp130 subunit, gp130act. Cell proliferation rate was determined and clones were examined for neuroendocrine differentiation by morphological change, upregulation of CgA and serotonin and formation of dense core vesicles with LNCaP parental cells as the control. Xenograft formation was examined and compared in immunocompromised mice.

Results

Gp130act expression promoted significant neuroendocrine differentiation in vitro as determined by a NE like morphology change (increased neurite like extension formation), elevated CgA expression and the formation of dense core vesicles (DCV). These measures concurred with those examined in LNCaP cells following 100 ng/ml IL‐6 treatment. Further investigation of the LNCaP gp130act cells in vivo, in immunocompromised androgen intact mice, confirmed that the NE like morphology, as determined by histological and high resolution transmission electron microscopy, was maintained.

Conclusions

NE differentiation was initiated by the expression of gp130act in a ligand independent manner, highlighting the importance of gp130 in the neuroendocrine differentiation process. Further investigation of upregulated/downregulated gene expression in these cells may provide valuable insight into the NE differentiation process. © 2004 Wiley‐Liss, Inc.
Loss of heterozygosity in chromosomal region 16q24.3 associated with progression of prostate cancer
Authors: Härkönen Päivi , Kyllönen Atte P. , Nordling Stig , Vihko Pirkko
Published: July 2004

Background

The molecular mechanisms underlying the development and progression of prostate cancer have remained poorly understood. To find out potential genetic markers likely to underlie tumor progression, the pattern of allelic loss on chromosome arm 16q in matched primary, locally recurrent, and metastatic prostate cancer specimens was analyzed in the present study.

Methods

The frequency of loss of heterozygosity (LOH) in 74 tumor specimens (62 primary cancer foci and 12 metastatic tumors) collected from 33 prostate cancer patients was determined by fragment analysis using 17 polymorphic microsatellite markers.

Results

The overall frequency of patients showing allelic loss at one or more loci on 16q was 68% (21/31) in primary tumors and 90% (28/31) in recurrent tumors. Of the individual markers, D16S520, locating in region 16q24.3, exhibited a statistically significant development of LOH during disease recurrence (P < 0.01). Regarding distant metastases, instead, there seemed to be no allelic loss events exclusively typical of metastatic tumors at 16q.

Conclusions

The data suggest the location of gene(s) related to prostate cancer progression at 16q24.3. © 2004 Wiley‐Liss, Inc.
Comparison of the zones of the human prostate with the seminal vesicle: Morphology, immunohistochemistry, and cell kinetics
Authors: Laczkó István , Hudson David L. , Freeman Alex , Feneley Mark R. , Masters John R.
Published: July 2004

Background

The prostate contains three glandular zones (central, peripheral, transition) with widely differing susceptibilities to cancer and benign prostatic hyperplasia (BPH). Most of the prostate is derived from urogenital sinus, but the central zone may be derived from Wolffian duct, in common with the seminal vesicles (SV). The peripheral zone is the most frequent site of cancer and the transition zone is the almost exclusive site of BPH.

Method

We compared the histology and immunohistochemistry of the SV with those of the prostate zones in order to identify differences associated with susceptibility to disease or different embryological origins. Sections from the prostates of nine organ donors (aged 15–36) were stained for tissue‐specific markers, antigens previously shown to stain differentially between the zones and markers of cell proliferation and cell death.

Results

Neuroendocrine cells were absent from the SV and significantly fewer neuroendocrine cells were seen in the central zone compared to the peripheral zone. Most of the SV epithelium stained for lactoferrin, compared to approximately one‐third of central zone and only 2% of peripheral zone epithelial cells. The proliferative index of the central zone was approximately 50% lower and the incidence of apoptotic cells approximately half that of the peripheral and transition zones.

Conclusions

The central zone has features in common with both the SV and the other zones of the prostate. The higher incidence of proliferative diseases in the transition and peripheral zones may be associated with the higher rate of cell turnover observed in these zones. © 2004 Wiley‐Liss, Inc.
Giant magnetic moment dynamics in Pd
Authors: Tovar Costa M. V. , de Castro Barbosa A. C. , Costa A. T.
Published: July 2004

We investigate the magnetic behavior of one substitutional Fe impurity on a Pd host, near the surface and in the bulk. We employ an itinerant electron picture and an underlying realistic electronic structure including the five d bands and the sp electrons. The ferromagnetic ground state is obtained by treating the on‐site Coulomb repulsion self‐consistently in mean field approximation. We obtain the spectrum of magnetic excitations by calculating the transverse dynamic susceptibility in the Random Phase Approximation. Our results reproduce qualitatively the strong polarization observed in such systems. We show that the magnetic excitations of the cluster formed by the Fe impurity and the surrounding polarized Pd atoms are strongly damped. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auger neutralization of He ions on Ag surfaces: surface type and azimuthal orientation dependence
Authors: Bandurin Yu. , Esaulov V. A. , Guillemot L. , Monreal R. C.
Published: July 2004

Neutralization of He+ ions in grazing incidence scattering on Ag(111) and Ag(110) surfaces is studied. These measurements reveal the existence of an order of magnitude difference in the probability of ion survival on Ag(110) and Ag(111). The effect of changing the direction of ion scattering along the surface azimuthal orientation is investigated. The experimental results are discussed in terms of survival from Auger neutralization, whose rates are derived theoretically. Molecular dynamics simulation of scattered ion trajectories are performed and the surviving ion fractions are then calculated using the theoretical Auger neutralization rates, without adjustable parameters. The calculations agree quite well with the experimental data and show that the observed differences in the neutralization probabilities on these surfaces are related to different extensions of the electron density beyond the surface, resulting from different atomic packing. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐local versus local neutralization of slow He ions in surface scattering
Authors: Draxler M. , Beikler R. , Taglauer E. , Zeppenfeld P. , Bauer P.
Published: July 2004

When an ion of kinetic energyEis scattered at a large angle from a surface atom, different types of charge exchange processes may occur: (i) capture of an electron by the ion on the incoming trajectory (Auger neutralization AN), (ii) capture or loss of an electron during the close encounter (collision induced neutralization CIN or reionization CIR). The relative importance of these processes depends on the ion‐target combination and the impact energy. In particular, collision‐induced processes need a close encounter and thus occur only above a certain threshold energyEth. This has consequences forP+, the yield of ions amongst all projectiles scattered into a fixed solid angle: as long asEEththe scaling properties ofP+are more complex, since thenP+depends on both,v⟂andE, due to the contribution of local charge exchange processes. We present experimental results for the neutralization of slow He ions backscattered from a polycrystalline Cu surface and discuss the relative importance of local and nonlocal processes in the energy regime 1–7 keV. Usually, it is assumed that the projectiles are scattered by surface atoms in a single binary collision. In many cases, this assumption is a good approximation, but it is not completely valid: to some extent also double and multiple scattering processes contribute to the scattered intensity. We show that the ion yield is hardly affected by double scattering, due to the high neutralization probability in the high density electron gas at the surface. By means of Monte‐Carlo simulations we discuss how the presence of plural scattering influences the determination ofP+. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic studies of metal high‐k dielectrics: transition metal oxides and silicates, and complex rare earth/transition metal oxides
Authors: Lucovsky G. , Hong J. G. , Fulton C. C. , Zou Y. , Nemanich R. J. , Ade H. , Scholm D. G. , Freeouf J. L.
Published: July 2004

This paper uses X‐ray absorption spectroscopy to the study of electronic structure of the transition metal oxides TiO2, ZrO2 and HfO2, Zr and Hf silicate alloys, and the complex oxides, GdScO3, DyScO3 and HfTiO4. Qualitative and quantitative differences are identified between dipole allowed intra‐atomic transitions from core p‐states to empty d*‐ and s*‐states, and inter‐atomic transitions from transition metal and oxide 1s states to O 2p* that are mixed with transition metal d*‐ and s*‐states for transition metal oxides and silicate alloys. The complex oxide studies have focused on the O K1 edge spectra. Differences between the spectral peak energies of the lowest d*‐features in the respective O K1 spectra are demonstrated to scale with optical band gap differences for TiO2, ZrO2 and HfO2, as well as the complex oxides providing important information relevant to applications of TM oxides as high‐k gate dielectrics in advanced Si devices. This is demonstrated through scaling relationships between (i) conduction band offset energies between Si and the respective dielectrics, and the optical band gaps, and (ii) the optical band gaps, the conduction band offset energies, and the electron tunneling masses as functions of the atomic d‐state energies of the transition metal atoms. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface chemistry effects on vacancy and interstitial annihilation on Si(001)
Authors: Kirichenko Taras A. , Banerjee Sanjay K. , Hwang Gyeong S.
Published: July 2004

Using density functional theory slab calculations we have investigated the effect of surface passivation on vacancy and interstitial annihilation on the Si(001) surface. We find that interstitials and vacancies are both stabilized at the clean and H‐/Cl‐terminated surfaces, with an energy gain of about 2–3 eV relative to those at the fifth subsurface layer where the surface effect becomes insignificant. This suggests that the Si surface is an effective sink for vacancies and interstitials, irrespective of surface passivation. However, our calculations show that the stability of vacancies and interstitials within the topmost three subsurface layers is greatly influenced by surface passivation, due to (i) strong interaction with surface Si dangling orbitals and (ii) rearrangement of surface atoms in the clean surface case. The chemical effect of adsorbates itself appears to be unimportant in the defect surface annihilation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Valence and conduction band offsets of a ZrO2/SiOxNy/n‐Si CMOS gate stack: A combined photoemission and inverse photoemission study
Authors: Sayan S. , Bartynski R. A. , Zhao X. , Gusev E. P. , Vanderbilt D. , Croft M. , Banaszak Holl M. , Garfunkel E.
Published: July 2004

The densities of states above and below the Fermi energy for the ZrO2/SiOxNy/n‐Si system are examined by photoemission and inverse photoemission and compared with results from first principles calculations. The measured band gap of ZrO2 is 5.68 eV and the valence and conduction band offsets relative to silicon are 3.40 and 1.16 eV respectively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)