bluuebunny/crossref_metadata_2025 huggingface dataset:
Tesmin transcription is regulated differently during male and female meiosis
Authors: Olesen Christian , Møller Morten , Byskov Anne Grete
Published: December 2003

Tesmin is a protein with homology to the metal‐binding motif of the metallothionein protein family. Tesmin has been described as a testis‐specific transcript, which starts to accumulate in 8‐day‐old mouse spermatocytes. Herein, a differential display comparing meiotic gene expression in embryonic ovaries and mature testes also revealed the presence of the Tesmin transcript in fetal ovaries as well as in fetal and adult heart. Time‐course experiments showed that Tesmin was expressed in a characteristic development‐related manner in fetal ovaries. Only a weak expression was observed at E12½, the strongest signal was reached at E14½, whereas the signal declined between E14½ and E16½. This transitional expression coincides with the early stages of the female meiotic prophase I. In the male, however, Tesmin was expressed in all stages of meiotic prophase I except preleptonema and leptonema. In situ hybridization further showed that the mRNA level increased during prophase I in the male, with the strongest expression seen at the transition from mid‐ to late pachytema (Stage VII–VIII). Furthermore, initiation of Tesmin transcription paralleled that of the synaptonemal complex protein 1 transcript (Scp1) in the fetal ovary and prepubertal testis. We, therefore, propose that Tesmin is likely to have a function in both the male and female meiotic prophase I. Moreover, the distinct difference in both the timing and the level of mRNA accumulation in the two gender's meiotic prophase I suggests that Tesmin transcription may be controlled by two different mechanisms during male and female meiosis. Mol. Reprod. Dev. 67: 116–126, 2004. © 2004 Wiley‐Liss, Inc.
α and β spectrin distribution during the differentiation of pyriform cells in follicles of lizard Podarcis sicula
Authors: Ricchiari Loredana , Carmela Vaccaro Maria , Marina Prisco , Rosa Carotenuto , Annamaria Liguoro , Piero Andreuccetti
Published: December 2003

Using α and β spectrin mammalian antibodies on Western blotting, we demonstrated that lizard ovarian follicles contain two isoforms of α spectrin, Mr 94 and 134 kDa, and a 230 kDa β spectrin, and that their pattern modifies in relation to pyriform cell differentiation. In fact, a positive immunoreaction is firstly evident within follicular epithelium of previtellogenic follicles when small cells differentiate into pyriform cells via intermediate cells. Later on, immunostain is present in pyriform cells and in the oocyte cortex that previously appears unstained. It is noteworthy that immunostain is also present on small cells located in contact with the oocyte membrane, but not on those located under the basal lamina and among pyriform cells, not engaged in pyriform cell differentiation. During the subsequent stages of previtellogenic phase, spectrin immunostain over the follicular epithelium and in the oocyte cortex does not change. By contrast, in vitellogenic follicles, when the follicular epithelium is constituted only by small cells, immunostain is evident at the level of the oocyte cortex and the cytoplasm of regressing pyriform cells. The present data strongly suggest that the α and β spectrin pattern put in evidence during the different phases of lizard oocyte growth is related to the differentiation of small into pyriform cells, where such protein may guarantee a relationship between surface glycoproteins (Andreuccetti et al., 2001: Anat Rec 263:1–9), and the cytoskeleton distribution (Maurizii et al., 2000: Raf Mol Reprod Dev 57:159–166). Furthermore, the distribution of spectrin mRNA, similar to that observed for the protein, demonstrates that spectrin, once synthesized within pyriform cells, is transferred through intercellular bridges in the oocyte cortex, thus confirming that pyriform cells are nurse that significantly are involved in the oocyte growth. Finally, the present data demonstrate that α spectrin of lizard ovarian follicles has Mr quite different from those so far reported and may constitute a new group of isoforms. This important result will be the focus of future experiments. Mol. Reprod. Dev. 67: 101–107, 2004. © 2004 Wiley‐Liss, Inc.
Expression profiling of the developing testis in wild‐type and Dazl knockout mice
Authors: Maratou Klio , Forster Thorsten , Costa Yael , Taggart Mary , Speed Robert M. , Ireland John , Teague Peter , Roy Douglas , Cooke Howard J.
Published: December 2003

Genetic understanding of male‐factor infertility requires knowledge of gene expression patterns associated with normal germ cell differentiation. The mouse is one of the best models of mammalian fertility due to its well‐characterized genetics and the existence of many infertile mutants both naturally occurring and experimentally induced. We used cDNA microarrays firstly to investigate normal gene expression in the wild‐type (wt) testis and secondly to gain a better insight into the effect of the disruption of the Dazl gene on spermatogenesis. We constructed a cDNA microarray from a subtracted and normalized adult testis library and focused on six developmental time‐points during the initial synchronous wave of spermatogenesis. The results suggest that in the wild‐type testis, 89.5% of genes on our chip change expression dramatically during the time‐course. To identify patterns in the gene‐expression data, a k‐means clustering algorithm and principal component analysis were used. In the Dazl knockout testes, the majority of genes remain at baseline levels of expression, because absence of Dazl has a severe effect on cell‐types present in the testis. Although in the prepubescent Dazl‐null mice the final point reached in germ cell development is the leptotene‐zygotene stage, the microarray results suggest that lack of Dazl expression has a detectable effect on the mRNA complement of germ cells as early as day 5 when only type A spermatogonia are present. Mol. Reprod. Dev. 67: 26–54, 2004. © 2004 Wiley‐Liss, Inc.
Auditory neuropathy/dys‐synchrony: Diagnosis and management
Authors: Berlin Charles I. , Hood Linda , Morlet Thierry , Rose Kelly , Brashears Shanda
Published: December 2003

Auditory brainstem responses (ABRs) and otoacoustic emissions (OAEs) are objective measures of auditory function, but are not hearing tests. Normal OAEs reflect normal cochlear outer hair cell function, and an ABR indicates a synchronous neural response. It is quite possible for a patient to have normal OAEs but absent or grossly abnormal ABR and a behavioral audiogram that is inconsistent with either test. These patients, who may constitute as much as 10% of the diagnosed deaf population, have auditory neuropathy/dys‐synchrony (AN/AD). To diagnose AN/AD accurately, ABRs are obtained in response to condensation and rarefaction clicks to distinguish cochlear microphonics (CM) from neural responses. Appropriate management is confounded by variation among patients and changes in auditory function in some patients over time. Recommendations for management include visual language exposure through methods such as American Sign Language (ASL), Cued Speech, or baby signs, and closely following patients. MRDD Research Reviews 2003;9:225–231. © 2003 Wiley‐Liss, Inc.
Early amplification options
Authors: Gabbard Sandra Abbott , Schryer Jennifer
Published: December 2003

Children with permanent hearing loss have been remediated with hearing amplification devices for decades. The influx of young infants identified with hearing loss through successful newborn hearing screening programs has established a need for amplification resources for infants within the first six months of life. For the approximately two of every 1000 infants born who are identified with bilateral hearing loss [Mehl and Thomson, 1998, Pediatrics 101, p. e4], the use of amplification is commonly the first step in treating the sequella of their loss. The use of hearing aids, combined with early intervention, has been shown to significantly improve the speech and language skills of young children with hearing loss [Yoshinaga‐Itano, 2000, Seminars in Hearing 21, p. 309]. Speech and language delays have contributed to compromised academic performance of school aged children with hearing loss [Johnson et al., 1997, Educational Audiology Handbook, Singular Publishing, San Diego]. Most hard‐of‐hearing and deaf children use hearing aids and other assistive listening devices every day throughout their lifetime and the life expectancy of a hearing aid is only five to eight years. The current challenge for pediatric audiologists is selecting and evaluating the available amplification to provide the best options for children and their families. Amplification technology has seen an explosion in growth the past few years and the options continue to expand rapidly. This article examines currently available amplification technology and reviews the selection criteria that may be used for infants and young children. Issues such as style, type, amplification features, signal processing strategies, and verification and validation tools are also discussed. MRDD Research Reviews 2003;9:236–242. © 2003 Wiley‐Liss, Inc.
Cochlear implants in young children
Authors: Niparko John K. , Blankenhorn Rebecca
Published: December 2003

The cochlear implant is best characterized as a device that provides access to the sound environment. The device enables the hearing pathway to respond to environmental and speech sounds, providing informational cues from the surroundings and from others that may escape visual detection. As the developmental effects of a profound hearing loss are multiple, cochlear implants have been applied to ever younger children in an attempt to promote a more normal level of developmental learning through audition. In deafness, transducer elements of the inner ear fail to trigger auditory nerve afferent nerves in the presence of sound input. However, large reserves of afferent fibers exist even in the auditory nerve of a profoundly deaf patient. Furthermore, these nerve fibers retain the ability to respond to prosthetic activation. Through developmental learning in the early, formative years, auditory centers of the brain appear capable of processing information from the implant to provide speech comprehension and oral language development. Multichannel implants have replaced original single channel designs. multichannel devices enable larger percentages of recipients to recognize the spoken word without visual cues because they provide spectral information in addition to temporal and intensity cues. Testing under conditions of auditory (implant)‐only input reveals significant open‐set speech understanding capabilities in more than 75% of children after three years of device use. The benefit provided by implants may vary with a number of conditions including: hearing history, age of deafness onset, age at implantation, etiology of deafness, linguistic abilities, and the presence of a motivated system of support of oral language development. Patient variables should be given individual consideration in judging candidacy for a cochlear implant and in planning rehabilitative and education services after surgery and activation of the device. MRDD Research Reviews 2003;9:267–275. © 2003 Wiley‐Liss, Inc.
Variation of the relaxographic “shutter‐speed” for transcytolemmal water exchange affects the CR bolus‐tracking curve shape
Authors: Yankeelov Thomas E. , Rooney William D. , Li Xin , Springer Charles S.
Published: December 2003

Contrast reagents (CRs) may enter the tissue interstitium for a period after a vascular bolus injection. As the amount of interstitial CR increases, the longitudinal relaxographic NMR “shutter‐speed” (T–1) for the equilibrium transcytolemmal water exchange process increases. The quantity T–1 is given by |r1o[CRo] + R1o0 – R1i| (where r1o and [CRo] represent the interstitial (extracellular) CR relaxivity and concentration, respectively, and R1o0 and R1i are the extra‐ and intracellular 1H2O relaxation rate constants, respectively, in the absence of exchange). The increase of T–1 with [CRo] causes the kinetics of the water exchange equilibrium to appear to decrease. Here, analytical theory for two‐site‐exchange processes is combined with that for pharmacokinetic CR delivery, extraction, and distribution in a method termed BOLus Enhanced Relaxation Overview (BOLERO©). The shutter‐speed effect alters the shape of the bolus‐tracking (B‐T) time‐course. It is shown that this is mostly accounted for by the inclusion of only one additional parameter, which measures the mean intracellular lifetime of a water molecule. Simulated and real data demonstrate that the effect of shutter‐speed variation on pharmacokinetic parameters can be very significant: neglecting this effect can lead to an underestimation of the parameter values by 50%. This phenomenon can be heterogeneous. Within a tiny gliosarcoma implanted in the rat brain, the interstitial CR in the tumor core never rises to a level sufficient to cause apparent slowing of the exchange process. However, within the few microns needed to reach the proliferating rim, this occurs to a significant degree. Thus, even relative pharmacokinetic quantities can be incorrectly represented in a parametric map that neglects this effect. The BOLERO analysis shows promise for in vivo vascular phenotyping in pathophysiology. It also includes a provision for approximating the separation of the perfusion and permeability contributions to CR extravasation. Magn Reson Med 50:1151–1169, 2003. © 2003 Wiley‐Liss, Inc.
Investigation of the microstructure of the isolated rat heart: A comparison between T*2‐ and diffusion‐weighted MRI
Authors: Köhler Sascha , Hiller Karl‐Heinz , Waller Christiane , Bauer Wolfgang R. , Haase Axel , Jakob Peter M.
Published: December 2003

Myocardial fiber structure can be determined with diffusion‐weighted (DW) MRI as well as with high‐resolution T*2 imaging. The purpose of the present study was twofold: to provide a more quantitative description of T*2‐based myocardial fiber contrast, and to compare the T*2‐based fiber structure with high‐resolution (78 μm in‐plane, 1‐mm slice thickness) DW images of the isolated rat heart at 11.75 T. This study demonstrates that the static dephasing regime is responsible for visualization of myocardial microstructure, and that the dynamic dephasing regime can be neglected. In comparison with DW experiments, T*2 mapping and DW images yield almost equivalent information on myocardial fiber structure. Magn Reson Med 50:1144–1150, 2003. © 2003 Wiley‐Liss, Inc.
Real‐time volumetric flow measurements with complex‐difference MRI
Authors: Thompson Richard B. , McVeigh Elliot R.
Published: December 2003

Blood flow in large vessels can be noninvasively evaluated with phase‐contrast (PC) MRI by encoding the spin velocity to the image phase. Conventional phase‐difference processing of the flow‐encoded image data yields velocity images. Complex‐difference processing is an alternative to phase‐difference methods, and has the advantage of eliminating signal from stationary spins. In this study, two acquisitions with differential flow encoding are subtracted to yield a single projection that contains signal from only those spins moving in the direction of the flow‐encoding gradients. The increase in acquisition efficiency allows real‐time flow imaging with a temporal window as short as two acquisition lengths (60 ms). Validation of the complex‐difference method by comparison with conventional gated‐segmented PC‐MRI in a flow phantom yielded a correlation of r > 0.99. Peak arterial flow rates in the popliteal artery and desending aorta measured in vivo with the complex‐difference method were 0.92 ± 0.06 of the values measured with conventional PC imaging. Real‐time in vivo volumetric flow imaging of transient flow events is also presented. Magn Reson Med 50:1248–1255, 2003. Published 2003 Wiley‐Liss, Inc.
Comparison of longitudinal metabolite relaxation times in different regions of the human brain at 1.5 and 3 Tesla
Authors: Ethofer Thomas , Mader Irina , Seeger Uwe , Helms Gunther , Erb Michael , Grodd Wolfgang , Ludolph Albert , Klose Uwe
Published: December 2003

In vivo longitudinal relaxation times of N‐acetyl compounds (NA), choline‐containing substances (Cho), creatine (Cr), myo‐inositol (mI), and tissue water were measured at 1.5 and 3 T using a point‐resolved spectroscopy (PRESS) sequence with short echo time (TE). T1 values were determined in six different brain regions: the occipital gray matter (GM), occipital white matter (WM), motor cortex, frontoparietal WM, thalamus, and cerebellum. The T1 relaxation times of water protons were 26–38% longer at 3 T than at 1.5 T. Significantly longer metabolite T1 values at 3 T (11–36%) were found for NA, Cho, and Cr in the motor cortex, frontoparietal WM, and thalamus. The amounts of GM, WM, and cerebrospinal fluid (CSF) within the voxel were determined by segmentation of a 3D image data set. No influence of tissue composition on metabolite T1 values was found, while the longitudinal relaxation times of water protons were strongly correlated with the relative GM content. Magn Reson Med 50:1296–1301, 2003. © 2003 Wiley‐Liss, Inc.
Catheter‐directed contrast‐enhanced coronary MR angiography in swine using magnetization‐prepared True‐FISP
Authors: Green Jordin D. , Omary Reed A. , Schirf Brian E. , Tang Richard , Li Debiao
Published: December 2003

Contrast‐enhanced (CE) coronary magnetic resonance angiography (MRA) following intraarterial (IA) injection of contrast agent was compared using two sequences in swine: magnetization‐prepared fast imaging with steady‐state precession (True‐FISP), and magnetization‐prepared fast low‐angle shot (FLASH). Thick‐slice projection images were acquired with submillimeter in‐plane spatial resolution (0.9 × 0.8 mm2). The magnetization‐preparation scheme provided a clear delineation of the major coronary arteries with excellent background suppression. The True‐FISP acquisition resulted in an increase in signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) by approximately a factor of 2 over FLASH (P < 0.05). Magnetization‐prepared True‐FISP is a promising technique for catheter‐directed CE thick‐slice projection coronary MRA. Magn Reson Med 50:1317–1321, 2003. © 2003 Wiley‐Liss, Inc.
Sickle red blood cells accumulate in tumor
Authors: Brown S.L. , Ewing J.R. , Nagaraja T.N. , Swerdlow P.S. , Cao Y. , Fenstermacher J.D. , Kim J.H.
Published: December 2003

The preferential accumulation of sickle blood cells in tumor vasculature is demonstrated noninvasively using MRI and sickle red blood cells loaded with Gd‐DTPA and invasively by two other techniques. The distribution of red blood cells in rat brain tumors relative to normal brains were measured using three separate techniques: MRI of Gd‐DTPA loaded cells, fluorescent microscopy detection of Oregon Green 488 fluorescence conjugated to a streptavidin‐biotin complex that binds to red blood cell surface proteins, and autoradiography using a technetium 99mTc‐labeling kit. Labeled red cells were infused intravenously in rats with brain tumors. Sickle cells preferentially accumulated in tumor relative to normal brain, with highest concentrations near the tumor / normal tissue boundary, whereas control normal red cells did not preferentially aggregate at the tumor periphery. This demonstrates the potential of sickle red blood cells to accumulate in the abnormal tumor vessel network, and the ability to detect their aggregation noninvasively and at high spatial resolution using MRI. The application of the noninvasive measurement of sickle cells for imaging tumor neovasculature, or as a delivery tool for therapy, requires further study. Magn Reson Med 50:1209–1214, 2003. © 2003 Wiley‐Liss, Inc.
Efficient k‐space sampling by density‐weighted phase‐encoding
Authors: Greiser Andreas , von Kienlin Markus
Published: December 2003

Acquisition‐weighting improves the localization of MRI experiments. An approach to acquisition‐weighting in a purely phase‐encoded experiment is presented that is based on a variation of the sampling density in k‐space. In contrast to conventional imaging or to accumulation‐weighting, where k‐space is sampled with uniform increments, density‐weighting varies the distance between neighboring sampling points Δk to approximate a given radial weighting function. A fast, noniterative algorithm has been developed to calculate the sampling matrix in one, two, and three dimensions from a radial weighting function w(k), the desired number of scans NAtot and the nominal spatial resolution Δxnom. Density‐weighted phase‐encoding combines the improved shape of the spatial response function and the high SNR of acquisition‐weighting with an extended field of view. The artifact energy that results from aliasing due to a small field of view is substantially reduced. The properties of density‐weighting are compared to uniform and to accumulation‐weighted phase‐encoding in simulations and experiments. Density‐weighted 31P 3D chemical shift imaging of the human heart is shown which demonstrates the superior performance of density‐weighted metabolic imaging. Magn Reson Med 50:1266–1275, 2003. © 2003 Wiley‐Liss, Inc.
Femoro‐tibial cartilage metrics from coronal MR image data: Technique, test–retest reproducibility, and findings in osteoarthritis
Authors: Glaser Christian , Burgkart Rainer , Kutschera Andrea , Englmeier Karl‐Hans , Reiser Maximilian , Eckstein Felix
Published: December 2003

MRI‐based measures of cartilage morphology are being increasingly used as surrogate markers in osteoarthritis. In contrast to other knee joint surfaces, quantitative analysis of the femoral condyles from sagittal MRI suffers from limited precision. The objective, therefore, was to develop a technique for reproducible assessment of femoral cartilage morphology from coronal image data. Coronal MR images (3D T1‐w FLASHwe) of the knee were obtained in 16 healthy volunteers and in 7 patients with severe osteoarthritis (OA, prior to knee arthroplasty), with repositioning between repeated scans. After segmentation the cartilage volume, thickness, and joint surface areas were quantified in the tibia and in an anatomically defined region of the femoral condyle. Immediate test‐retest interscan precision errors (CV%) for femoral cartilage volume were 3.0% (SD = 26 μl) and 3.2% (29 μl) medially and laterally in volunteers, and 3.0% (34 μl) and 7.0% (37 μl) in OA patients. The estimated loss, from cross sectional data, in the patients in the medial femoral condyle (–61%/–4.4 SD) was higher than that in the medial tibia (–45%/–3.1 SD) and compared favorably with precision errors (ratio > 16:1). The technique proposed overcomes some of the problems associated with sagittal scans and thus shows high promise for reliable assessment of femoro‐tibial cartilage loss in OA. Magn Reson Med 50:1229–1236, 2003. © 2003 Wiley‐Liss, Inc.
High‐resolution 1H NMR spectroscopy in a live mouse subjected to 1.5 Hz magic angle spinning
Authors: Wind Robert A. , Hu Jian Zhi , Rommereim Donald N.
Published: December 2003

It is demonstrated that the resolution of the 1H NMR metabolite spectrum in a live mouse can be significantly enhanced by an ultraslow magic angle spinning of the animal combined with a modified phase‐corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2 T field while spinning the animal at a speed of 1.5 Hz. It was found that even in this relatively low field, with PHORMAT an isotropic spectrum is obtained with line widths that are a factor of 4.6 smaller than those obtained in a stationary mouse. It is concluded that in vivo PHORMAT has the potential to significantly increase the utility of 1H NMR spectroscopy for biochemical and biomedical animal research. Magn Reson Med 50:1113–1119, 2003. © 2003 Wiley‐Liss, Inc.
Amide proton transfer (APT) contrast for imaging of brain tumors
Authors: Zhou Jinyuan , Lal Bachchu , Wilson David A. , Laterra John , van Zijl Peter C.M.
Published: December 2003

In this work we demonstrate that specific MR image contrast can be produced in the water signal that reflects endogenous cellular protein and peptide content in intracranial rat 9L gliosarcomas. Although the concentration of these mobile proteins and peptides is only in the millimolar range, a detection sensitivity of several percent on the water signal (molar concentration) was achieved. This was accomplished with detection sensitivity enhancement by selective radiofrequency (RF) labeling of the amide protons, and by utilizing the effective transfer of this label to water via hydrogen exchange. Brain tumors were also assessed by conventional T1‐weighted, T2‐weighted, and diffusion‐weighted imaging. Whereas these commonly‐used approaches yielded heterogeneous images, the new amide proton transfer (APT) technique showed a single well‐defined region of hyperintensity that was assigned to brain tumor tissue. Magn Reson Med 50:1120–1126, 2003. © 2003 Wiley‐Liss, Inc.
New hybrid technique for accurate and reproducible quantitation of dynamic contrast‐enhanced MRI data
Authors: Li Ka‐Loh , Jackson Alan
Published: December 2003

The accuracy and precision of two major approaches for analyzing dynamic MRI data from the first passage of a Gd‐DTPA contrast bolus are examined, using a Monte Carlo simulation. Method 1 fits the contrast concentration curve of the first pass to a two‐compartment kinetic model to determine the tissue pharmacokinetic parameters. Method 2 decomposes intravascular and interstitial components of the first‐pass curve based on a leakage profile (LP) model. Based on the results of these Monte Carlo simulations, a new “hybrid” method is proposed that combines both analytical approaches to optimize accuracy and precision of estimates of Ktrans, ve, and vp. The new method was evaluated by computer simulation and used on experimental results from a patient with primary brain tumors. The new method has the potential to provide more accurate quantification of tissue plasma volume and vessel permeability. Magn Reson Med 50:1286–1295, 2003. © 2003 Wiley‐Liss, Inc.
In vivo quantification of choline compounds in the breast with 1H MR spectroscopy
Authors: Bolan Patrick J. , Meisamy Sina , Baker Eva H. , Lin Joseph , Emory Timothy , Nelson Michael , Everson Lenore I. , Yee Douglas , Garwood Michael
Published: December 2003

This work describes a methodology for quantifying levels of total choline‐containing compounds (tCho) in the breast using in vivo 1H MR spectroscopy (MRS) at high field (4 Tesla). Water is used as an internal reference compound to account for the partial volume of adipose tissue. Peak amplitudes are estimated by fitting one peak at a time over a narrow frequency band to allow measurement of small metabolite resonances in spectra with large lipid peaks. This quantitative method significantly improves previously reported analysis methods by accounting for the variable sensitivity of breast 1H MRS measurements. Using this technique, we detected and quantified a tCho peak in 214 of 500 in vivo spectra. tCho levels were found to be significantly higher in malignancies than in benign abnormalities and normal breast tissues, which suggests that this technique could be used to diagnose suspicious lesions and monitor response to cancer treatments. Magn Reson Med 50:1134–1143, 2003. © 2003 Wiley‐Liss, Inc.
Evaluation of two‐dimensional L‐COSY and JPRESS using a 3 T MRI scanner: from phantoms to human brain in vivo
Authors: Thomas M. Albert , Hattori Noriaki , Umeda Masahiro , Sawada Tohru , Naruse Shoji
Published: December 2003

Localized versions of two‐dimensional (2D) magnetic resonance spectroscopic (MRS) sequences, namely JPRESS and L‐COSY, have been implemented on a whole‐body 3T MRI/MRS scanner. Volume selection was achieved using three slice‐selective radio‐frequency (RF) pulses: 90°–180°–180° in JPRESS and 90°–180°–90° in L‐COSY with a CHESS sequence prior to voxel localization for global water suppression. The last 180° RF pulse was used for resolving the J‐coupled cross peaks in JPRESS, whereas the last 90° RF pulse was used for coherence transfer between J‐coupled metabolites in L‐COSY. A head MRI coil for ‘transmission’ and a 4 inch receive surface coil for ‘reception’ or a head coil transmit/receive were used. A total of 16 healthy volunteers were investigated using these 2D MRS sequences. Voxel sizes of 18 and 27 ml were localized in the occipito‐parietal gray and white matter regions and the total duration for each 2D signal acquisition was typically 35 min. Compared with 2D L‐COSY, reduced spectral width along the second spectral dimension and shorter 2D spectral acquisition were the major advantages of 2D JPRESS. In contrast, increased spectral width along the new spectral dimension in L‐COSY resulted in an improved spectral dispersion enabling the detection of several brain metabolites at low concentrations that have not been resolved using the conventional one‐dimensional (1D) MRS techniques. Due to increased sampling rate, severe loss of metabolite signals due to T2 during t1 was a major drawback of 2D JPRESS in vivo. Copyright © 2003 John Wiley & Sons, Ltd.
REST‐PEEP: reduced scan time phase‐encoded echo planar imaging
Authors: Guilfoyle David N. , Hrabe Jan
Published: December 2003

Echo planar methodology can be used for rapid acquisition in three dimensions of k‐space. There are two groups of sequences which have thus far been implemented. The first group is characterized by three‐dimensional acquisition from a single RF excitation. Echo planar shift mapping and echo volumar imaging are single‐shot chemical shift imaging and three‐dimensional spatial imaging techniques, respectively. Even though these methods are extremely fast, their spatial and spectral resolutions are poor. In the second group of sequences, echo planar imaging acquisition is repeated for every phase‐encode gradient step to improve upon the spatial resolution and signal‐to‐noise ratio at the expense of acquisition time. Here we report a novel combination of these two groups of sequences aimed at providing additional flexibility in trade‐offs between the spectral bandwidth, signal‐to‐noise ratio, spatial resolution and imaging time. Preliminary results for both chemical shift imaging and three‐dimensional spatial imaging are presented. The chemical shift imaging was optimized for excitation of the N‐acetyl aspartate (NAA). An interesting consequence of our approach is that the Nyquist ghost is transferred from the spectrum to the metabolite image. Copyright © 2001 John Wiley & Sons, Ltd.
Three‐dimensional MRI of cerebral projections in rat brain in vivo after intracortical injection of MnCl2
Authors: Allegrini Peter R. , Wiessner Christoph
Published: December 2003

In this study we investigated the potential of in vivo MRI detection of axonal Mn2+ transport for tracing neuronal projections originating in the sensorimotor cortex in healthy and lesioned rat brains. Special attention was given to the potential of visualizing neuronal sprouting of central nervous system across the midline. After injecting unchelated MnCl2 into the forelimb area of sensorimotor cortex of 18 healthy and 10 lesioned rats corticofugal projections could be traced through the internal capsule to the cerebral peduncle and the pyramidal decussation. Although the neuronal tract was visible as early as 6 h after MnCl2 injection, best contrast was achieved after 24–48 h. Beside the cortico‐spinal tract, the cortico‐thalamic fibres were also visualized by anterograde Mn2+ transport. Cortico‐striatal fibres were partially masked by the very high signal near the MnCl2 injection site but could be discerned as well. Slight, diffuse signal enhancement of cortical tissue contralateral to the MnCl2 injection site in healthy rat brains suggests interhemispheric connections or passive diffusion of Mn2+. However, enhanced fibre tract contrast connecting both hemispheres was visible 16 weeks after onset of focal photothrombotic cortical injury. In conclusion our study has shown that we were able to visualize reproducibly the main descending corticofugal projections and interhemispheric connections by non‐invasive MRI after localized injection of MnCl2. The appearence of interhemispheric Mn2+‐enhanced fibres after photothrombotic focal injury indicates that the method may bear potential to follow non‐invasively gross plastic changes of connectivity in the brain after injury. Copyright © 2001 John Wiley & Sons, Ltd.
An adaptive survivability admission control algorithm using backup path for high‐speed networks
Authors: Lo Chi‐Chun , Chuang Bin‐Wen
Published: December 2003

In this paper, we propose an adaptive survivability admission control algorithm using a backup path for high‐speed networks. For each call request, the proposed algorithm selects a combination of working path and backup path. Two BP selection methods, min‐cost and min‐expectation, are suggested. Computational experiments indicate that the proposed algorithm significantly reduces the consumption of backup capacity while still maintaining 100% survivability upon a single link failure and near 80% survivability upon double link failures. Copyright © 2003 John Wiley & Sons, Ltd.
Network capacity allocation for traffic with time priorities
Authors: Liu Xian
Published: December 2003

The packet switching techniques are undergoing evolution. The conventional ‘best effort’ approach will no longer be the dominant service. The next generation of IP networks must provide QoS to customers. Inadequacy is obvious when the conventional capacity allocation (CA) models are applied to the new IP architecture. In this paper, we propose several CA models that characterize: (1) the service priority scheme; (2) the service preemption scheme; and (3) the non‐Poisson traffic in which the packets follow heavy tailed distributions. Copyright © 2003 John Wiley & Sons, Ltd.
A scalable key‐management scheme with minimizing key storage for secure group communications
Authors: Tseng Yuh‐Min
Published: December 2003

Recently, many group communication services have become the focus for future developments in the Internet and wireless network applications, such as video‐conferencing, collaborative work, networking games or online videos. In particular, these applications require data delivery from one sender to a large number of authorized receivers. Therefore, secure multicast communication will become an important networking issue in the future. Using a common encryption key only known by authorized members to encrypt transmitted data is a practical approach. But, whenever a group member joins or leaves the group, the common encryption key must be updated to ensure both past and future secrecy. As a result, minimizing key update communication cost and the key storage requirement of a group controller is a critical issue in a scalable and dynamically changing large group. A new key‐management scheme is proposed to reduce the key storage requirement of a group controller to a constant size, which is far better than that of the previously proposed schemes, while retaining the same key update communication cost. In addition, the correlation between the key storage requirement of each group member and key update communication cost are also presented. Copyright © 2003 John Wiley & Sons, Ltd.
Consistency adjustments for pairwise comparison matrices
Authors: Farkas András , Lancaster Peter , Rózsa Pál
Published: December 2003

This paper is concerned with the development of a ‘best’ rank one transitive approximation to a general paired comparison matrix in a least‐squares sense. A direct attack on the non‐linear problem is frequently replaced by a sub‐optimal linear problem and, here, the best procedure of this kind is obtained. The Newton–Kantorovich method for the solution of the non‐linear problem is also studied, including the role of the best linear approximation as a starting point for this method. Numerical examples are included. Copyright © 2002 John Wiley & Sons, Ltd.
A centrosymmetric matrix based technique for the interpolation of a Hermitian signal
Authors: Hanna Magdy Tawfik , Mansoori Sana Ahmed
Published: December 2003

This work is concerned with the signal interpolation problem, i.e. given only samples of a signal, a method is derived for evaluating its samples on finer grids. The derivation is based on a discrete‐time decimation formula. In the special case where the known samples have the Hermitian property, two schemes are presented and mathematically proved to result in interpolated points having the same property. The first scheme does not utilize the known sample at the origin and results in a square system of equations to be solved for the unknown interpolated points of the signal. The second scheme has the merit of utilizing all the known samples, but it results in an overdetermined system of equations to be solved by the least squares method. The exploitation of the elegant properties of the involved centrosymmetric matrices is central to the treatment presented here. Copyright © 2002 John Wiley & Sons, Ltd.
The impact of state governance structures on management and performance of public organizations: A study of higher education institutions
Authors: Knott Jack H. , Payne A. Abigail
Published: December 2003

Legislative statutes are passed by political majorities which support structures that insulate the implementing
agency from its political opponents over time. Political actors also respond to different constituencies.
Depending on the broad or narrow base of these constituencies, actors favor different kinds of governance
structures. We apply this theoretical framework to the question of whether the state governance structures of
boards of higher education affect the way university managers allocate resources, develop sources of revenue, and
promote research and undergraduate education. Over the past two decades state governments have given considerable
attention to state governance issues, resulting in many universities operating in a more regulated setting today.
This paper develops a classification of higher education structures and shows the effects of differences in these
structures on university management and performance using a data set that covers the period from 1987 to 1998. The
analysis suggests that, for most of the measures, productivity and resources are higher at universities with a
statewide board that is more decentralized and has fewer regulatory powers. © 2004 by the Association for
Public Policy Analysis and Management.
Will empowering developers to challenge exclusionary zoning increase suburban housing choice?
Authors: Mitchell James L.
Published: December 2003

The municipal zoning process in the United States has come under increasing attack as a tool to create and maintain suburban socioeconomic homogeneity by mandating sprawl‐producing single‐family detached houses at the expense of less costly townhouses, apartments, and mobile homes. Beginning in the 1970s, the Supreme Courts of the neighboring states of Pennsylvania and New Jersey addressed municipal exclusionary zoning in different ways: Pennsylvania empowered residential developers to compel municipalities practicing exclusionary zoning to authorize market‐rate development of all types of housing, while developer empowerment in New Jersey was conditioned upon inclusion of low‐ and moderate‐income units. Using aerial survey and housing census data over a 20‐year period, this article finds that outcomes by housing type over a 20‐year period in Pennsylvania municipalities around Philadelphia were more diverse than those in adjacent New Jersey municipalities. © 2004 by the Association for Public Policy Analysis and Management.
Public wage differentials and the treatment of occupational differences
Authors: Belman Dale , Heywood John S.
Published: December 2003

Past research demonstrates that the estimated size of the federal government earnings differential shrinks
substantially with the addition of detailed occupational controls. Possible explanations for this reduction are:
controlling for the differing sectoral distributions of common occupations, and controlling for detailed
occupations unique to each sector. While occupational detail does not eliminate the federal differential, more
than two‐thirds of the reduction in the federal differential comes from controlling for unique occupations
and, moreover, this is equivalent to excluding all observations in unique occupations. This finding is contrasted
with that for the local sector in which the differing distribution of common occupations largely explains the
pattern of the differential. © 2004 by the Association for Public Policy Analysis and Management.
Not just angiogenesis—wider roles for the angiopoietins
Authors: Jones Pamela F
Published: December 2003

Since the discovery of the angiopoietins, much interest has been focused on their biological actions and their potential use as therapeutic targets. It is generally accepted that the angiopoietins play an important role in angiogenesis and hence are described as angiogenic factors. However, it is becoming increasingly clear that this is not their only role and it is likely that the angiopoietins have important roles in a wider range of biological and pathological functions. Copyright © 2003 John Wiley & Sons, Ltd.
NOV (CCN3) regulation in the growth plate and CCN family member expression in cartilage neoplasia
Authors: Yu Chunying , Le Anh‐Thy , Yeger Herman , Perbal Bernard , Alman Benjamin A
Published: December 2003

Growth plate chondrocytes undergo a coordinated differentiation process resulting in terminal differentiation and new bone formation. Enchondromas are pre‐malignant, benign cartilaginous lesions that arise from growth plate chondrocytes that fail to undergo terminal differentiation. NOV (nephroblastoma overexpressed) is a member of the CCN family of proteins, which share a common multi‐modular organization. While the role of NOV in chondrocyte development and cartilage neoplasia is not known, other CCN family members play a role in chondrocyte differentiation, or are differentially regulated in cartilage neoplasia. In embryonic murine growth plates, NOV was expressed in pre‐hypertrophic and early hypertrophic chondrocytes. PTHrP treatment (which inhibits terminal differentiation) decreased NOV expression in murine femurs maintained in organ culture, and decreased the activity of a NOV reporter construct in vitro. Expression of the CCN family members NOV, CTGF, CYR61, and WISP‐1 was examined in 15 chondrosarcomas of various grades and in three enchondromas. Expression of all of the family members was lower in the higher‐grade tumours. As identification of the grade of cartilage neoplasia can sometimes be difficult using histology alone, the level of expression of CCN family members could be a useful adjunct in the determination of tumour grade. Copyright © 2003 John Wiley & Sons, Ltd.
Cyclin E gene (CCNE) amplification and hCDC4 mutations in endometrial carcinoma
Authors: Cassia Raúl , Moreno‐Bueno Gema , Rodríguez‐Perales Sandra , Hardisson David , Cigudosa Juan C , Palacios José
Published: December 2003

Cyclin E overexpression occurs in a subset of endometrial carcinomas (ECs), but the molecular mechanisms underlying this alteration remain to be established. The present study has analysed amplification of the cyclin E gene (CCNE) and mutation in hCDC4, the gene coding for the F‐box protein, which tags phosphorylated cyclin E for proteosomal degradation, to ascertain whether these alterations might be responsible for cyclin E overexpression in ECs. Cyclin E and p53 expression was studied by immunohistochemistry in eight atypical endometrial hyperplasias (AEHs), 51 endometrioid endometrial carcinomas (EECs), and 22 non‐endometrioid endometrial carcinomas (NEECs). CCNE amplification was analysed by fluorescence in situ hybridization (FISH). Mutations in exons 2–11 of the hCDC4 gene were screened by PCR–SSCP–sequencing. Finally, the polymorphic marker D4S1610 was used to assess loss of heterozygosity (LOH) in the hCDC4 gene. Cyclin E overexpression was found in 26/81 (32%) cases and was associated with the histological type of the lesion, since it was not found in any AEHs but was present in 27% of EECs and 54.5% of NEECs (p = 0.035). Cyclin E overexpression was associated with histological grade (p = 0.011) and p53 immunostaining in EECs (p = 0.033). CCNE amplification was found in 6 of 37 (16%) ECs examined. There was a significant association between CCNE amplification and the histological type of the lesion, since five (83%) of the six cases with amplification were NEECs (p = 0.008). One EEC harboured an hCDC4 mutation: a CGA to CAA (Arg/Gln) change at codon 479. In addition, D4S1610 LOH was found in 7 of 23 (30%) informative cases analysed, but no correlation with cyclin E overexpression was found. However, the tumour with hCDC4 mutation also showed LOH. This is the first study demonstrating that cyclin E overexpression is associated with gene amplification in ECs, these alterations being more frequent in NEECs. Although hCDC4 exhibits a low mutation frequency in ECs overexpressing cyclin E, it seems to function as a tumour suppressor gene that is involved in endometrial carcinogenesis. Copyright © 2003 John Wiley & Sons, Ltd.
The presence of high‐risk HPV combined with specific p53 and p16INK4a expression patterns points to high‐risk HPV as the main causative agent for adenocarcinoma in situ and adenocarcinoma of the cervix
Authors: Zielinski G Denise , Snijders Peter JF , Rozendaal Lawrence , Daalmeijer Nathalie Fransen , Risse Elle KJ , Voorhorst Feja J , Jiwa N Medi , van der Linden Hans C , de Schipper Frits A , Runsink Arnold P , Meijer Chris JLM
Published: December 2003

Adenocarcinoma in situ (ACIS) and adenocarcinoma (AdCA) of the cervix are frequently missed in population‐based screening programmes. Adding high‐risk HPV (hrHPV) testing to cervical cancer screening might improve the detection rate of ACIS and AdCA. Since the exact proportion of AdCAs of the cervix that can be attributed to hrHPV infection is still a matter of debate, a comprehensive study was performed of hrHPV presence in ACIS and AdCA of the cervix. Archival formalin‐fixed specimens of indisputable ACIS (n = 65) and AdCA (n = 77) of the cervix were tested for hrHPV DNA by GP5+/6+ PCR‐enzyme immunoassay (EIA) and type‐specific E7 PCR for 14 hrHPV types. Further immunostaining for p16INK4A and p53 was performed to assess alternative pathways of carcinogenesis potentially unrelated to HPV. hrHPV DNA was found in all (100%) ACISs and 72 (94%) cervical AdCAs, whereas none of 20 endometrial AdCAs scored hrHPV‐positive. HPV 18 was most prevalent and found as single or multiple infection in 68% of ACISs and 55% of cervical AdCAs. Diffuse immunostaining for p16INK4a, a potential marker of hrHPV E7 function, was significantly more frequent in hrHPV‐positive cervical AdCAs (19/20; 95%) than in those without hrHPV (1/5; 20%; p < 0.001). Immunostaining for p53, pointing to stabilized wild‐type or mutant p53 protein, was significantly more frequent in hrHPV cervical AdCAs negative for hrHPV (p = 0.01). No difference in p16INK4a and p53 immunostaining was found between hrHPV‐negative cervical AdCAs and endometrial AdCAs. Hence, only a minority of cervical AdCAs displayed absence of HPV DNA and immunostaining profiles suggestive of an aetiology independent of HPV. Since all ACISs and nearly all cervical AdCAs were hrHPV‐positive, the incorporation of hrHPV testing in cervical cancer screening programmes is likely to decrease markedly the incidence of cervical AdCA. Copyright © 2003 John Wiley & Sons, Ltd.