bluuebunny/crossref_metadata_2025 huggingface dataset:
Proteomic analysis of human prostate cancer†
Authors: Ahram Mamoun , Best Carolyn J. M. , Flaig Michael J. , Gillespie John W. , Leiva Isabel M. , Chuaqui Rodrigo F. , Zhou Ge , Shu Hungjun , Duray Paul H. , Linehan W. Marston , Raffeld Mark , Ornstein David K. , Zhao Yingming , Petricoin Emanuel F. , Emmert‐Buck Michael R.
Published: August 2002

Proteomics is a promising approach in the identification of proteins and biochemical pathways involved in tumorigenesis. In an effort to discover such proteins and pathways that are deregulated in prostate tumorigenesis, cellular proteomes of matched normal prostate epithelial cells and high‐grade prostate cancer cells were analyzed by tissue microdissection, two‐dimensional electrophoresis, and mass spectrometry. Forty protein alterations were detected in the tumors; however, the majority of these changes were not shared among the 12 neoplasms. In contrast, parallel cDNA microarray analysis identified a number of common gene expression changes. The marked heterogeneity of the observed protein alterations may have significance with regard to tumor biology and research strategies for molecular profiling analyses of human prostate cancer. Published 2002 Wiley‐Liss, Inc.
Enhanced apoptosis under low serum conditions in human glioblastoma cells by connexin 43 (Cx43)
Authors: Huang Ruochun , Liu Ya‐Guang , Lin Ying , Fan Yan , Boynton Alton , Yang Dongzi , Huang Ruo‐Pan
Published: August 2002

Connexin 43 (Cx43), a structural component of gap junctions, is believed to function as a tumor suppressor gene. Previously, we showed that expression of Cx43 suppresses cell proliferation and tumorigenicity of human glioblastoma cells [Huang et al., Cancer Res 58:5089–5096, 1998] and enhances apoptosis in response to chemotherapeutic agents [Huang et al., Int J Cancer 92:130–138, 2001]. In the present study, we demonstrated that expression of Cx43 in human glioblastoma cells potentiated an apoptotic program under low‐serum conditions. The Cx43‐mediated effect was coupled with a decreased expression of the specific apoptosis‐inhibitor bcl‐2. Overexpression of bcl‐2 in Cx43‐transfected cells conferred resistance to apoptosis induced under low‐serum conditions, suggesting that the Cx43‐mediated apoptosis under low‐serum conditions is regulated, in part, through the downregulation of bcl‐2 expression. Furthermore, application of the phosphatidylinositol‐3′‐OH kinase inhibitor LY294002 specifically induced apoptosis in Cx43‐transfected cells. Our results demonstrate a new role of Cx43 in the mediation of apoptosis under low serum conditions. © 2001 Wiley‐Liss, Inc.
Association of chorea and motor neuron disease
Authors: Pradat Pierre‐François , Salachas François , Lacomblez Lucette , Patte Nathalie , Leforestier Nadine , Gaura Véronique , Meininger Vincent
Published: August 2002

Amyotrophic lateral sclerosis (ALS) is classically characterized by the presence of symptoms or signs of upper and lower motor neuron impairment and sparing of other neuronal systems.1 We report on a patient who was primarily diagnosed as typical ALS and developed chorea 10 years after the onset of motor neuron signs. © 2002 Movement Disorder Society.
Intrafamilial phenotypic variability of the DYT1 dystonia: From asymptomatic TOR1A gene carrier status to dystonic storm
Authors: Opal Puneet , Tintner Ron , Jankovic Joseph , Leung Joanne , Breakefield Xandra O. , Friedman Jennifer , Ozelius Laurie
Published: August 2002

When primary torsion dystonia is caused by a GAG deletion in the TOR1A gene (DYT1 dystonia), it typically presents with an early‐onset dystonia involving distal limbs, subsequently spreading to a generalized dystonia. We describe a large family with an unusually broad variability in the clinical features of their dystonia both with regard to severity and age of onset. The proband of this family succumbed in his second decade to malignant generalized dystonia, whereas other family members carrying the same mutation are either asymptomatic or display dystonia that may be focal, segmental, multifocal, or generalized in distribution. One family member had onset of her dystonia at age 64 years, probably the oldest reported in genetically confirmed DYT1 dystonia. We conclude that marked phenotypic heterogeneity characterizes some families with DYT1 dystonia, suggesting a role for genetic, environmental, or other modifiers. These findings have implications for genetic testing and counseling. © 2002 Movement Disorder Society.
Dystonia in Wilson's disease
Authors: Svetel Marina , Kozić Duško , Stefanova Elka , Semnic Robert , Dragaševič Nataša , Kostič Vladimir S.
Published: August 2002

The frequency and type of dystonic movements, as well as brain abnormalities, as depicted with magnetic resonance imaging (MRI), which might correlate with dystonia, were studied in 27 consecutive patients with a neurologic form of Wilson's disease (WD) and optimized treatment. Dystonia was found in 10 patients (37%), being generalized in half of them, while two patients had segmental, two patients multifocal dystonia, and one patient bilateral foot dystonia. Dystonia was a presenting sign in four patients and developed later in the course of the disease in six patients, despite the administered therapy for WD. Putamen was the only structure significantly more frequently lesioned in dystonic (80%) in comparison to WD patients without dystonia (24%), suggesting a relation between abnormalities in this brain region and dystonic movements in WD. © 2001 Movement Disorder Society.
Corticobasal syndrome with tau pathology
Authors: Cordato N.J. , Halliday G.M. , McCann H. , Davies L. , Williamson P. , Fulham M. , Morris J.G.L.
Published: August 2002

Six cases with a clinical corticobasal syndrome (progressive asymmetric apraxia and parkinsonism unresponsive to levodopa) and tau pathology were selected from 97 brain donors with parkinsonism. Postmortem volumetric measures of regional brain atrophy (compared with age/sex‐matched controls) were correlated with clinical features and the degree of underlying cortical and subcortical histopathology. At death, no significant asymmetry of pathology was detected. All cases had prominent bilateral atrophy of the precentral gyrus (reduced by 22–54%) with other cortical regions variably affected. Subcortical atrophy was less severe and variable. Two cases demonstrated widespread atrophy of basal ganglia structures (44–60% atrophy of the internal globus pallidus) and substantial subcortical pathology consistent with a diagnosis of progressive supranuclear palsy (PSP). The remaining four cases had typical pathology of corticobasal degeneration. In all cases, neuronal loss and gliosis corresponded with subcortical atrophy, while the density of cortical swollen neurons correlated with cortical volume loss. Atrophy of the internal globus pallidus was associated with postural instability, while widespread basal ganglia histopathology was found in cases with gaze palsy. This study confirms the involvement of the precentral gyrus in the corticobasal syndrome and highlights the variable underlying pathology in these patients. © 2001 Movement Disorder Society
Treatment of neuroleptic malignant syndrome with subcutaneous apomorphine monotherapy
Authors: Wang Han‐Cheng , Hsieh Yoloung
Published: August 2002

A 20‐year‐old psychiatric patient receiving haloperidol treatment developed acute‐onset fever, rigidity, and mental changes. Subcutaneous apomorphine was given alone for treatment. The patient had rapid clinical improvement after the treatment. Serial blood examinations showed decline and subsequent normalization of the creatine phosphokinase levels.
Hand orthosis as a writing aid in writer's cramp
Authors: Taş Nihal , Karataş Gülçin Kaymak , Sepici Vesile
Published: August 2002

Writer's cramp is a focal, task‐specific dystonia of the hand and wrist. It primarily affects people who do a significant amount of writing, and causes difficulties in writing. We present five cases with writer's cramp who showed improvement in their writing ability with an applied hand orthosis. © 2001 Movement Disorder Society.
Botulinum toxin antibody type A titres after cessation of botulinum toxin therapy
Authors: Dressler Dirk , Bigalke Hans
Published: August 2002

In some patients, therapy with botulinum toxin type A (BT‐A) becomes ineffective due to formation of antibodies (BT‐A‐AB). The time course of BT‐A‐AB titres after cessation of BT‐A therapy was quantitatively studied to determine whether and when they might drop. Thirteen patients (eight women, five men) with various dystonic syndromes and complete secondary therapy failure (CSTF) were included in this study (age at initiation of BT‐A therapy, 48.2 ± 11.3 years; number of injection series, 7.7 ± 2.9; treatment time, 678.8 ± 385.6 days; mean interinjection interval, 90.4 ± 35.5 days; mean single dose, 546.7 ± 336.9 EMU; cumulative dose, 4185.1 ± 3375.7 EMU [1 EMU = 1 botox MU = 3 dysport MU]). During a monitoring period of at least 750 days after occurrence of CSTF, two or more BT‐A‐AB tests using the quantitative mouse diaphragm assay were performed. Eight of 13 BT‐A‐AB titres decreased. The onset of decrease could be detected after between approximately 500 and 1,750 days. After 1,250 to 2,250 days they had dropped below a level of 0.002 U/ml, where CSTF is unlikely. Five of 13 BT‐A‐AB titres did not decrease. For three of these five, the monitoring period was less than 1,500 days; a chance to drop remained. The other two were monitored for up to 2,400 days. Patients with decreasing and nondecreasing BT‐A‐AB titres did not exhibit statistically significant differences in either clinical characteristics or treatment parameters. When BT‐A therapy was stopped the majority of BT‐A‐AB titres eventually decreased, allowing reinitiation of BT‐A therapy. Application of new BT‐A preparations with low antigenic potency might then become an interesting treatment option. © 2002 Movement Disorder Society.
X‐linked dystonia (“Lubag”) presenting predominantly with parkinsonism: A more benign phenotype?
Authors: Evidente Virgilio Gerald H. , Gwinn‐Hardy Katrina , Hardy John , Hernandez Dena , Singleton Andrew
Published: August 2002

“Lubag,” or Filipino X‐linked dystonia, typically presents with either pure dystonia (that inexorably becomes generalized) or combined dystonia–parkinsonism. We report on three cases of Lubag presenting with isolated parkinsonism without dystonia or late‐onset dystonia and a slower course. © 2001 Movement Disorder Society.
Bimanual coordination in Parkinson's disease: Deficits in movement frequency, amplitude, and pattern switching
Authors: Byblow Winston D. , Summers Jeffery J. , Lewis Gwyn N. , Thomas Julie
Published: August 2002

Six patients with idiopathic Parkinson's disease (PD) and six age‐matched controls participated in a variety of rhythmic bimanual coordination tasks. The main goal of the task was to perform inphase or antiphase patterns of pronation and supination of the forearms at a specified tempo, and to switch from one pattern to the other upon presentation of a visual cue. The availability of advance information was varied to examine whether deficits would emerge under choice versus pre‐cue constraints. In pre‐cue conditions, the subjects knew in advance which hand would be cued to initiate pattern change. In choice conditions, the cued hand was not known until the imperative stimulus was presented. Overall, the PD patients made movements with significantly lower frequencies and smaller amplitudes relative to controls. Patients exhibited spontaneous pattern switching from antiphase to inphase at significantly lower movement frequencies than controls. During intentional switching trials, the control group was significantly faster at initiating pattern change. PD and control groups differed in the time to initiate pattern switching to a greater extent under choice conditions, suggesting that patients used advance information to increase the speed of their response. The control group exhibited a preference for spontaneous switching and intentional switching through the subdominant hand. Patients exhibited a switching preference using the impaired limb (whether or not it was subdominant). The control group made more correct responses when the subdominant side was either pre‐cued or presented in choice conditions. The patients maintained the subdominant/impaired side advantage under pre‐cue conditions but not choice. In the maintenance of rhythmic movement, individuals with PD were able to use advance information in terms of both speed and accuracy. © 2001 Movement Disorder Society.
A new consistent discrete‐velocity model for the Boltzmann equation
Authors: Panferov Vladislav A. , Heintz Alexei G.
Published: August 2002

This paper discusses the convergence of a new discrete‐velocity model to the Boltzmann equation. First the consistency of the collision integral approximation is proved. Based on this we prove the convergence of solutions for a modified model to renormalized solutions of the Boltzmann equation. In a numerical example, the solutions to the discrete problems are compared with the exact solution of the Boltzmann equation in the space‐homogeneous case. Copyright © 2002 John Wiley & Sons, Ltd.
A variational calculation of TE and TM cutoff wavenumbers in circular eccentric guides by conformal mapping
Authors: Yang Hyunkieu , Lee Sangseol
Published: August 2002

The cutoff wavenumbers of higher order modes in circular eccentric guides are computed with the variational analysis combined with a conformal mapping. A conformal mapping is applied to the variational formulation, and the variational equation is solved by the finite‐element method. Numerical results for TE and TM cutoff wavenumbers are presented for different distances between the centers and ratio of the radii. Comparisons with numerical results found in the literature validate the presented method. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 381–384, 2001.
A practical technique for optimum matching of two‐element antenna arrays
Authors: Ozdemir Caner
Published: August 2002

A fast and effective method for the matching of two‐ element symmetric antenna arrays is presented. The full geometry is subdivided into two half‐space problems with the help of an even‐ and odd‐mode (EOM) analysis scheme. An interpretation based on the EOM representation is made for any radiation pattern mode that is constructed by arbitrarily exciting the antenna ports. Also, a relationship between the radiation efficiency for the full geometry and the even‐ and odd‐mode S‐parameters is derived. A unique technique for matching the two‐element antenna arrays is developed by exploiting the EOM representation. Numerical examples that illustrate the effectiveness of our matching technique for different radiation pattern modes are provided. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 224–229, 2002.
Dependence of optical power confinement on core/cladding chiralities in chirofibers
Authors: Choudhury P. K. , Yoshino T.
Published: August 2002

An analytical study of the optical power confinement of a chirofiber is presented. Using Maxwell's field equations and considering the cases of meridional and skew modes, variation of the power confinement is presented in two events, viz. 1) with the change in cladding chirality (for fixed values of core chirality), and 2) with the change in core chirality (for fixed values of cladding chirality). Studies are made for two different fiber core diameters, and it is found that, in general, the power confinement in the core section reduces with the increase in its chirality admittance. Further, the amount of transmitted power increases with the mode index. However, as the core cross‐sectional size increases, the skew modes present almost similar behavior, and the power transported by them is much higher as compared to that by the meridional modes. Thus, the skew modes in such chirofibers with a little larger size present an event close to degeneracy, which is useful in integrated‐optic applications and optical‐communication systems. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 359–364, 2002.
MMIC medium‐power amplifier in K band with matching and power‐divider/combiner networks implemented with the use of lumped elements
Authors: Álvarez L. , Portilla J. , de la Fuente M.L. , Artal E.
Published: August 2002

The design and measurements of a monolithic K‐band medium‐power amplifier are reported. The matching, biasing, and power‐splitter networks have been implemented with the use of lumped elements, reducing the chip size. The model predictions of passive circuitry have been tested through electromagnetic simulations. The amplifier has shown interesting performance in K band. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 397–400, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10334
Genetic determinants of basal cell carcinoma risk*
Authors: Epstein Ervin
Published: August 2002

Basal cell carcinomas are can be induced by ionizing radiation, in particular in patients with the rare autosomal dominant basal cell nevus syndrome (BCNS). These patients also are prone to medulloblastomas, and curative ionizing radiation therapy for the latter is followed soon by the development of sheets of basal cell carcinomas in the overlying skin. Positional cloning of the gene mutant is BCNS patients has identified the hedgehog signaling pathway as crucial to the development of all basal cell carcinomas and presumably to this susceptibility to post‐ionizing radiation carcinogenesis. Thus this pathway is a candidate for susceptibility to second, post‐therapy cancers in the broader population. Med. Pediatr. Oncol. 36:555–558, 2001. © 2001 Wiley‐Liss, Inc.
Extraction of T2 from NMR linewidths in simple spin systems by use of reference deconvolution
Authors: Mladenov G. , Dimitrov V. S.
Published: August 2002

We investigated the possibility of obtaining transverse relaxation times through linewidth measurements in NMR spectra of simple spin systems (subsystems). The spectra are subjected to reference deconvolution and subsequently to time domain data analysis. The time for the experiment is usually short; stringent instrumental stability should be maintained during the experiment. The approach described here produces correct results if the lineshape is Lorentzian. Rough width estimation is achievable in other cases. As an additional result, detection of very small couplings is possible. Copyright © 2001 John Wiley & Sons, Ltd.
Expression of glutamate‐cysteine ligase during mouse development
Authors: Díaz Dolores , Krejsa Cecile M. , Kavanagh Terrance J.
Published: August 2002

The tripeptide glutathione (GSH), which plays a crucial role in protecting cells against oxidative stress, is synthesized in a two‐step process. The rate‐limiting step is the binding of glutamate and cysteine, which is catalyzed by the enzyme glutamate‐cysteine ligase (GCL). This enzyme is composed of two subunits: a large catalytic subunit (GCLc) and a smaller modifying subunit (GCLm), originating from different genes. Control of cellular GSH levels is essential for normal development. In the current study, we investigated the tissue distribution of Gclc and Gclm transcripts, as well as GCLc protein, in the developing mouse embryo. We found that both mRNAs were highly expressed in the liver and CNS at gestational day 10 (gd 10) and gd 12, with Gclm being more abundant than Gclc in the liver relative to other tissues. Also, the expression of the two subunit mRNAs was not always parallel in the embryo, in that some tissues expressed one of the subunits preferentially, suggesting that the two genes are differentially expressed during mouse development. The GCLc protein was also widely expressed throughout the embryo, and, in general, it co‐localized with the Gclc mRNA. Mol. Reprod. Dev. 62: 83‐91, 2002. © 2002 Wiley‐Liss, Inc.
Flow cytometric sperm sorting: Effects of varying laser power on embryo development in swine*
Authors: Guthrie H.D. , Johnson L.A. , Garrett W.M. , Welch G.R. , Dobrinsky J.R.
Published: August 2002

This study was conducted to determine fertilization rate and embryo development using the Beltsville Sperm Sexing Technology with two different laser power outputs, 25 and 125 milliwatts (mW). Freshly ejaculated boar semen was diluted; one aliquot was not stained or sorted (nonsort) and a second aliquot was stained with Hoechst 33342 and sorted as a complete population, not separated into X and Y populations (all‐sort). Ovulation controlled gilts were surgically inseminated with 2 × 105 spermatozoa (44–46 hr after human chorionic gonadotropin (hCG)) into the isthmus of each oviduct, one oviduct receiving nonsort and the other all‐sort at 25 or 125 mW. A total of 426 embryos were flushed from oviducts at slaughter 43 hr after laparotomy and prepared for determination of fertilization and cleavage rates using confocal laser microscopy for analysis of actin cytoskeleton and chromatin configuration. The percentage of fertilized eggs and embryos was less for the 25 mW all‐sort compared to nonsort or the 125 mW all‐sort (77.9 vs. 96.3 and 96.2%, P < 0.05). The percentage of fragmented embryos was greater for the 25 mW all‐sort than the nonsort (15.2 vs. 4.5%, P < 0.05), but did not differ significantly from 125 mW all‐sort mean (7.2%). The percentage of normal embryos (80.4% overall) did not differ (P > 0.05) among treatments. However, the rate of embryo development was slower (P < 0.05) after insemination with the 25 mW all‐sort spermatozoa compared to nonsort spermatozoa. Embryos in the 3–4 and 5–9 cell stages for the 25‐mW all‐sort and nonsort were 78 and 20% vs. 49 and 50%, respectively. The embryo percentages for the 125 mW (3–4 and 5–9 cell stages, 59 and 35%) did not differ significantly (P > 0.05) from the nonsort or 25 mW all‐sort. We conclude that the use of 125 mW laser power for sorting boar spermatozoa is advantageous to maintain high resolution separation and has no detrimental effect on embryo development compared to 25 mW. Mol. Reprod. Dev. 61: 87–92, 2002. © 2002 Wiley‐Liss, Inc.
Detection of lymph node metastases by contrast‐enhanced MRI in an experimental model
Authors: Wunderbaldinger Patrick , Josephson Lee , Bremer Christoph , Moore Anna , Weissleder Ralph
Published: August 2002

Lymph node size, the accumulation of a nodal lymphotrophic contrast agent (LCDIO), and MRI were compared as methods for detecting nodal metastases in an experimental murine model. Lymph node metastases (B16‐F1 melanoma expressing green fluorescent protein (GFP) and C57BL/6 mice) were generated to obtain a wide spectrum of nodes, including normal nodes and nodes bearing micrometastases, small metastases, or large metastases. Nodal uptake of LCDIO was measured using 111Indium‐labeled LCDIO and was found to be lower in micrometastastic nodes (4.20 ± 1.4%ID/gm) than in normal nodes (8.60 ± 0.22% ID dose/gram, P < 0.005). Nodal tumor burden was quantified from the amount of GFP present in nodes measured using the Western blot method, and was found to correlate with the decrease of LCDIO uptake. By MRI, nodes bearing small and large metastases contained regions of high signal intensity (SI) that corresponded to the visual pattern of tumor in nodes. Micrometastatic nodes were distinguishable from normal nodes based on a diffuse pattern of inhomogeneous SI. The signal‐to‐background ratio (SBR) of normal nodes (0.0112 ± 0.0061) was different from micrometastatic nodes (0.179 ± 0.080, P < 0.00046) and nodes bearing small metastases (0.723 ± 0.269, P < 0.00013), with high degrees of significance. Magn Reson Med 47:292–297, 2002. © 2002 Wiley‐Liss, Inc.
Self‐calibrating parallel imaging with automatic coil sensitivity extraction
Authors: McKenzie Charles A. , Yeh Ernest N. , Ohliger Michael A. , Price Mark D. , Sodickson Daniel K.
Published: August 2002

Calibration of the spatial sensitivity functions of coil arrays is a crucial element in parallel magnetic resonance imaging (PMRI). The most common approach has been to measure coil sensitivities directly using one or more low‐resolution images acquired before or after accelerated data acquisition. However, since it is difficult to ensure that the patient and coil array will be in exactly the same positions during both calibration scans and accelerated imaging, this approach can introduce sensitivity miscalibration errors into PMRI reconstructions. This work shows that it is possible to extract sensitivity calibration images directly from a fully sampled central region of a variable‐density k‐space acquisition. These images have all the features of traditional PMRI sensitivity calibrations and therefore may be used for any PMRI reconstruction technique without modification. Because these calibration data are acquired simultaneously with the data to be reconstructed, errors due to sensitivity miscalibration are eliminated. In vivo implementations of self‐calibrating parallel imaging using a flexible coil array are demonstrated in abdominal imaging and in real‐time cardiac imaging studies. Magn Reson Med 47:529–538, 2002. © 2002 Wiley‐Liss, Inc.
Detunable transverse electromagnetic (TEM) volume coil for high‐field NMR
Authors: Vaughan J.T. , Adriany G. , Garwood M. , Yacoub E. , Duong T. , DelaBarre L. , Andersen P. , Ugurbil K.
Published: August 2002

Most high‐field MRI systems do not have the actively detuned body coils that are integral to clinical systems operating at 1.5T and lower field strengths. Therefore, many clinical applications requiring homogeneous volume excitation in combination with local surface coil reception are not easily implemented at high fields. To solve this problem for neuroimaging applications, actively detunable transverse electromagnetic (TEM) head coils were developed to be used with receive‐only surface coils for signal‐to‐noise ratio (SNR) gains and improved spatial coverage from homogeneously excited regions. These SNR and field of view (FOV) gains were achieved by application of a detunable TEM volume coil to human brain imaging at 4T. Magn Reson Med 47:990–1000, 2002. © 2002 Wiley‐Liss, Inc.
Improved efficiency in double‐inversion fast spin‐echo imaging
Authors: Parker Dennis L. , Goodrich K. Craig , Masiker Marilyn , Tsuruda Jay S. , Katzman Gregory L.
Published: August 2002

Double‐inversion fast spin‐echo (FSE) pulse sequences can be designed to provide excellent suppression of blood signal in black‐blood MRI. However, because a nonselective inversion is used, these sequences typically have been highly inefficient. In this work it is demonstrated that the efficiency of double‐inversion sequences can be greatly improved by a form of interleaving in which all of the slices to be imaged in a single pass are reinverted each time a signal is obtained from any single slice. To date, several studies have demonstrated a high level of blood suppression with these more efficient techniques. Magn Reson Med 47:1017– 1021, 2002. © 2002 Wiley‐Liss, Inc.
MRA of hemodialysis access grafts and fistulae using selective contrast injection and flow interruption
Authors: Bos Clemens , Smits Johannes H.M. , Zijlstra Jan J. , van der Mark Wil A.M.A. , Blankestijn Peter J. , Bakker Chris J.G. , Viergever Max A. , Mali Willem P.Th.M.
Published: August 2002

MR is a potentially attractive modality for evaluating hemodialysis access anatomy and function. However, the wide range of flow rates in the hemodialysis access complicates interpretation of phase contrast, time‐of‐flight, and even contrast‐enhanced MR angiograms. At high flow rates, signal voids may easily arise at mild narrowings or sharp‐angled anastomoses. A method is proposed which visualizes hemodialysis accesses without flow artifacts. Diluted Gd‐DTPA is hand‐injected directly into the access, while a cuff is used to reduce and subsequently interrupt access flow. Filling of the access is monitored using a fast projection technique with complex subtraction. When filling is satisfactory, a 3D acquisition is started. The feasibility of this selective contrast‐enhanced MR angiography technique is demonstrated in four Cimino‐fistulae and four PTFE grafts. Magn Reson Med 45:557–561, 2001. © 2001 Wiley‐Liss, Inc.
Whole body detection and imaging of nitric oxide generation in mice following cardiopulmonary arrest: Detection of intrinsic nitrosoheme complexes
Authors: Kuppusamy Periannan , Shankar Ravi A. , Roubaud Valerie M. , Zweier Jay L.
Published: August 2002

Ischemic tissues generate nitric oxide (NO) by direct reduction of tissue nitrite under the acidic conditions that occur during ischemia. In view of the important implications of this enzyme‐independent mechanism of NO generation on the pathogenesis and treatment of tissue injury, the NO formation in mice subjected to cardiopulmonary arrest was measured and imaged. Real‐time measurement of NO generation was performed by detection of naturally generated NO‐heme complexes in tissues using L‐band electron paramagnetic resonance (EPR) spectroscopy. To distinguish NO generated from nitrite, animals were labeled with isotopically enriched 15N‐nitrite. Mice were infused with nitrite (70 mg/kg, intravenous), cardiopulmonary arrest induced by an overdose of phenobarbital, and transferred to the EPR resonator. Measurements of NO generation were performed on the intact animal at the levels of the head, thorax, and abdomen. At the end of 3 hr, major organs were isolated and analyzed for their NO signal. The NO complexes were found to have maximum levels in lung, heart, and liver. Three‐dimensional spatial mapping of the NO complex in the intact animal subjected to cardiopulmonary arrest was performed using EPR imaging techniques. The images also confirmed the maximum formation in the lungs, heart, and liver. The present data reveal that mice subjected to cardiopulmonary arrest generate large amounts of NO, which is nitrite mediated. The observed signal was largely due to heme‐bound NO, which accounted for the high concentrations found in these organs. This increased NO formation during cardiopulmonary arrest could contribute to the difficulty of resuscitation after long periods of arrest. Magn Reson Med 45:700–707, 2001. © 2001 Wiley‐Liss, Inc.
Detection of an intense resonance at 2.4 ppm in 1H MR spectra of patients with severe late‐delayed, radiation‐induced brain injuries
Authors: Yeung David K.W. , Chan Yu‐leung , Leung Sing‐fai , Poon Priscilla M.K. , Pang Chi‐pui
Published: August 2002

Proton MRS and MRI were used to monitor the progression of severe cerebral radiation injuries in 10 patients over a period of 18 months. An unknown resonance (Px) in the 2.37–2.40 ppm region was consistently detected in the affected temporal lobes of four patients. The detection of Px was only confined to spectra with lactate (Lac) and in patients with the highest severity grading of radiation injury. The incidence of Px in Lac‐positive spectra was 42.8% (15/35) and in lesions with highest injury grading was 46.8% (15/32). Lesions with Px had significantly higher Lac/creatine (Cr) ratios and more extensive mass effect changes when compared to lesions without Px. The probable identity of Px was examined in the context of anaerobic glycolysis producing pyruvate (2.37 ppm) and the model of metabolic changes in brain abscess formation implicating succinate (2.40 ppm). Magn Reson Med 45:994–1000, 2001. © 2001 Wiley‐Liss, Inc.
New devices to deliver somatosensory stimuli during functional MRI
Authors: Graham S.J. , Staines W.R. , Nelson A. , Plewes D.B. , McIlroy W.E.
Published: August 2002

A new class of devices are described for improving investigation of somatosensory neuronal activation using fMRI. Dubbed magnetomechanical vibrotactile devices (MVDs), the principle of operation involves driving wire coils with small oscillatory currents in the large static magnetic field inherent to MRI scanners. The resulting Lorentz forces can be oriented to generate large vibrations that are easily converted to translational motions as large as several centimeters. Representative data demonstrate the flexibility of MVDs to generate different well‐controlled vibratory and tactile stimuli to activate special proprioceptive and cutaneous somatosensory afferent pathways. The implications of these data are discussed with respect to the literature on existing devices for producing sensorimotor activation, as well as expanding the scope of current fMRI investigations. Magn Reson Med 46:436–442, 2001. © 2001 Wiley‐Liss, Inc.
Sensitivity‐encoded spectroscopic imaging
Authors: Dydak Ulrike , Weiger Markus , Pruessmann Klaas P. , Meier Dieter , Boesiger Peter
Published: August 2002

Sensitivity encoding (SENSE) offers a new, highly effective approach to reducing the acquisition time in spectroscopic imaging (SI). In contrast to conventional fast SI techniques, which accelerate k‐space sampling, this method permits reducing the number of phase encoding steps in each phase encoding dimension of conventional SI. Using a coil array for data acquisition, the missing encoding information is recovered exploiting knowledge of the distinct spatial sensitivities of the individual coil elements. In this work, SENSE is applied to 2D spectroscopic imaging. Fourfold reduction of scan time is achieved at preserved spectral and spatial resolution, maintaining a reasonable SNR. The basic properties of the proposed method are demonstrated by phantom experiments. The in vivo feasibility of SENSE‐SI is verified by metabolic imaging of N‐acetylaspartate, creatine, and choline in the human brain. These results are compared to conventional SI, with special attention to the spatial response and the SNR. Magn Reson Med 46:713–722, 2001. © 2001 Wiley‐Liss, Inc.
Repetition time in echo planar functional MRI
Authors: Constable R. Todd , Spencer Dennis D.
Published: August 2002

To date, surprisingly little attention has been directed toward determining the optimum TR in a functional imaging experiment. A survey of the literature reveals a wide range of TRs, but little justification for a specific TR. Long‐TR functional imaging experiments provide maximum signal‐to‐noise ratio (SNR) in the raw images; allow for the collection of a large number of slice locations; and decrease the size of the data set acquired, simplifying storage and handling. This work, however, demonstrates that long‐TR imaging sacrifices statistical power when the paradigm timing is held fixed. That is, for a fixed‐run duration consisting of multiple activation/control blocks, shorter TR acquisitions (on the order of 1000 ms) provide better discrimination between the activated and nonactivated brain tissue regions than do long‐TR acquisitions (on the order of 4000 ms). Results are shown for modeling the functional imaging experiment and for three different paradigms performed on normal subjects. Magn Reson Med 46:748–755, 2001. © 2001 Wiley‐Liss, Inc.
Motor conduction studies in Miller Fisher syndrome with severe tetraparesis
Authors: Katsuno Masahisa , Ando Tetsuo , Hakusui Shigetaka , Yanagi Tsutomu , Sobue Gen
Published: August 2002

Some patients with Miller Fisher syndrome (MFS) have a severe tetraparesis such as that observed in Guillain–Barré syndrome (GBS). To determine whether pathophysiologic differences exist between the tetraparesis in MFS and that in GBS, we compared clinical and motor conduction findings in 4 MFS patients who developed severe tetraparesis with those in 5 MFS patients without tetraparesis, and 14 GBS patients. MFS patients with or without tetraplegia had normal motor conduction velocities, distal motor latencies, compound muscle action potential (CMAP) amplitudes, and F‐wave latencies. CMAP amplitude tended to be lower in tetraparetic MFS patients than in MFS patients without tetraparesis, but not significantly. F‐wave occurrence was slightly reduced in 1 MFS patient with tetraparesis and 1 MFS patient without tetraparesis. Motor conduction parameters were abnormal in 13 of 14 patients with GBS, and showed demyelinating features in 10. Our results suggest that the pathophysiology of tetraparesis in MFS differs from that in GBS. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Diabetic and nondiabetic lumbosacral radiculoplexus neuropathies: New insights into pathophysiology and treatment
Authors: Dyck P. James B. , Windebank Anthony J.
Published: August 2002

Diabetic lumbosacral radiculoplexus neuropathy (DLRPN) (also called diabetic amyotrophy) is a well‐recognized subacute, painful, asymmetric lower‐limb neuropathy that is associated with weight loss and type II diabetes mellitus. Nondiabetic lumbosacral radiculoplexus neuropathy (LRPN) has received less attention. Comparison of large cohorts with DLRPN and LRPN demonstrated that age at onset, course, type and distribution of symptoms and impairments, laboratory findings, and outcomes are similar. Both conditions are lumbosacral radiculoplexus neuropathies that are associated with weight loss and begin focally with pain but that evolve into widespread, bilateral paralytic disorders. Although both are monophasic illnesses, patients have prolonged morbidity from pain and weakness, and many patients become wheelchair‐dependent. Although motor‐predominant, there is unequivocal evidence that autonomic and sensory nerves are also involved. Cutaneous nerves from patients with DLRPN and LRPN show pathological evidence of ischemic injury (multifocal fiber loss, perineurial thickening and degeneration, neovascularization, microfasciculation, and swollen axons with accumulated organelles) and microvasculitis (mural and perivascular inflammation, separation and fragmentation of mural smooth muscle layers of microvessels and hemosiderin‐laden macrophages). Controlled trials with immune‐modulating therapies in DLRPN are in progress, and preliminary data suggest that such therapy may be beneficial in LRPN. It is likely that DLRPN and LRPN are immune‐mediated neuropathies that should be separated from chronic inflammatory demyelinating polyneuropathy and from systemic necrotizing vasculitis. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Length dependence of variables associated with temporal dispersion in human motor nerves
Authors: Schulte‐Mattler Wilhelm J. , Müller Tobias , Georgiadis Dimitrios , Kornhuber Malte E. , Zierz Stephan
Published: August 2002

Temporal dispersion in motor nerves is associated with changes of amplitude, area, duration, and Fourier spectra of compound muscle action potentials (CMAPs) when comparing responses to proximal and distal stimulation. These changes depend on the length of the nerve segment. To quantitatively assess this dependence, motor conduction studies of nerve segments of various lengths were performed in the median, ulnar, and tibial nerves of 86 test subjects, aged 4 to 73 years. Amplitude, area, duration, and spectral energy above 49 Hz of CMAPs were measured. Values after distal and proximal stimulation of each nerve segment were compared to determine amplitude decay, area decay, protraction, and high‐frequency attenuation. A significant length dependence of amplitude decay was found in the tibial and ulnar nerves, of area decay in the median and ulnar nerves, and of CMAP duration in the ulnar and tibial nerves. The length dependence of the high‐frequency attenuation was significant in all nerves studied. This report provides normative data for variables associated with temporal dispersion. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 527–533, 2001
Reproducibility of neurophysiological and myometric measurement in the ulnar nerve–abductor digiti minimi system
Authors: de Carvalho Mamede , Lopes Arminda , Scotto Manuel , Swash Michael
Published: August 2002

Reliability in strength and neurophysiological measurements is important in evaluating progression of neuromuscular diseases. No data are available on the variability of neurophysiological parameters as compared with maximal voluntary isometric contraction (MVIC) in the same muscles, in healthy subjects. A control population of 26 healthy subjects was studied twice on different days. We evaluated the reliability of neurophysiological parameters obtained from bilateral ulnar nerve stimulation, recording the response over the abductor digiti minimi (ADM) muscle, including distal motor latency, compound muscle potential amplitude and area, F‐wave frequency and mean F‐wave latency, and the derived neurophysiological index that we have described previously. MVIC force was measured in each session in both ADM muscles. The variances between the grouped data obtained in the two recording sessions were identical, indicating a low intrinsic variability with this experimental methodology. Comparison of the mean values obtained in the two sessions revealed no statistically significant differences. The reliability of these neurophysiological and strength measurements in the same nerve/muscle system suggests they may be useful in comparing the dynamics of weakness and neurophysiological change in neuromuscular disease. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1391–1395, 2001
Motor unit recruitment during lengthening contractions of human wrist flexors
Authors: Stotz Paula J. , Bawa Parveen
Published: August 2002

The purpose of this study was to revisit the question of recruitment of motor units during lengthening contractions because of conflicting views in the literature on this subject. Motor unit activity was recorded from the flexor carpi radialis muscle of four human subjects to compare the patterns of recruitment during lengthening and isometric contractions. Lengthening contractions were produced either when the subject voluntarily stopped opposing a background load or when an additional load was imposed on the already contracting muscle. In both cases, lengthening of the active muscle was produced at a variety of speeds, from quite slow to “as fast as possible.” No differences in recruitment order were observed between isometric and lengthening contractions at any speed of lengthening contraction. It is concluded that all contractions in normal humans recruit motor units in an orderly fashion from small to large, according to the size principle of motor unit recruitment. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1535–1541, 2001
Three‐dimensional analysis of the seismic behaviour of micropiles used in the reinforcement of saturated soil
Authors: Ousta R. , Shahrour I.
Published: August 2002

This paper includes a numerical study of the behaviour of micropiles used for the reinforcement of saturated soil. Analysis is carried out using the (u–p) formulation (displacement for the solid phase and pore‐pressure for the fluid phase) implemented in a three‐dimensional finite element program. The soil behaviour is described by means of a cyclic elastoplastic constitutive relation which was developed within the framework of the bounding surface concept. The paper is composed of three parts. The first one is concerned with a presentation of the numerical model; the second includes analysis of the seismic behaviour of a single micropile; the last part deals with the group effect under seismic loading. Copyright © 2001 John Wiley & Sons, Ltd.
Optimization routine for identification of model parameters in soil plasticity
Authors: Mattsson Hans , Klisinski Marek , Axelsson Kennet
Published: August 2002

The paper presents an optimization routine especially developed for the identification of model parameters in soil plasticity on the basis of different soil tests. Main focus is put on the mathematical aspects and the experience from application of this optimization routine. Mathematically, for the optimization, an objective function and a search strategy are needed. Some alternative expressions for the objective function are formulated. They capture the overall soil behaviour and can be used in a simultaneous optimization against several laboratory tests. Two different search strategies, Rosenbrock's method and the Simplex method, both belonging to the category of direct search methods, are utilized in the routine. Direct search methods have generally proved to be reliable and their relative simplicity make them quite easy to program into workable codes. The Rosenbrock and simplex methods are modified to make the search strategies as efficient and user‐friendly as possible for the type of optimization problem addressed here. Since these search strategies are of a heuristic nature, which makes it difficult (or even impossible) to analyse their performance in a theoretical way, representative optimization examples against both simulated experimental results as well as performed triaxial tests are presented to show the efficiency of the optimization routine. From these examples, it has been concluded that the optimization routine is able to locate a minimum with a good accuracy, fast enough to be a very useful tool for identification of model parameters in soil plasticity. Copyright © 2001 John Wiley & Sons, Ltd.
Influence of gender on the diurnal variation of urine production and micturition characteristics of the rat
Authors: Schmidt Frank , Yoshimura Yasukuni , Ni Rong‐Xiang , Kneesel Shawna , Constantinou Christos E.
Published: August 2002

The diurnal variation in the frequency/volume characteristics of male and female conscious rats was evaluated with reference to fluid consumption and urine production. Baseline values of the micturition volume and frequency of nine male and 10 female SD adult rats were measured over a 24‐hour time period. The level of initial hydration conditions was standardized with 5 ml of water administered orally. With animals in a metabolism chamber having free access to water, the total volume of water consumed, the frequency/volume characteristics during micturition and the urine production rate were derived from the measurements of voided volume as detected by a digital balance. To establish reliability of measurements two separate micturition studies were done per rat at an interval of 1 week. Mean frequency of micturition and mean volume voided per micturition and urine production rate were computed in 3‐hour time bins and represented over the 24‐hour period. In addition the mean values of the number of micturitions and mean micturated volumes during the day/dark cycle were evaluated. The results show significant gender specificity in water consumption, urine production, and diurnal variations in micturition frequency/volume characteristics. Females consistently consume significantly larger amounts of water (83%) than males while urine production rate was correspondingly higher in females. It is concluded that water consumption and urine production are gender‐specific. Because higher volumes of water are imbibed by females than males, the frequency/volume characteristic of micturition in the rat is also gender‐specific. Data suggest that the volume voided per micturition depends on the urine production rate.Neurourol. Urodynam. 20:287–295, 2001. © 2001 Wiley‐Liss, Inc.
Monitoring cytotoxic tumour treatment response by diffusion magnetic resonance imaging and proton spectroscopy
Authors: Kauppinen Risto A.
Published: August 2002

Exposure of tumours to anti‐cancer drugs, gene or radiation therapy consistently leads to an increase in water diffusion in the cases expressing favourable treatment response. The diffusion change coincides cytotoxic cell eradication and precedes volume reduction in drug or gene therapy‐treated experimental tumours. Interestingly, the recent studies from human brain tumour patients undergoing chemotherapy show similar behaviour of diffusion, suggesting important application for MRI in patient management. In this review observations from diffusion MRI and MRS in the tumours during cytotoxic treatment are summarized and the cellular mechanisms affecting molecular mobility are discussed in the light of tissue microenvironmental and microdynamic changes. Copyright © 2002 John Wiley & Sons, Ltd.