bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic process of phospholipid–protein interaction studied by capillary isoelectric focusing with whole‐column imaging detection
Authors: Bo Tao , Pawliszyn Janusz
Published: January 2006

Liposomes are vesicles formed by the aggregation of amphiphilic phospholipid molecules, which can mimic natural cell membranes. Interaction between liposome and protein is important for the structure and function of natural cell membranes. In this study, a CIEF method with whole‐column imaging detection was developed for monitoring the dynamic process of phospholipid–protein interactions. The CIEF profiles at successive interaction times clearly displayed the formation of the different conjugates between phospholipid and protein at different stages. Due to the diversity of the chemical and physical properties of targeted proteins in this study (trypsin inhibitor, β‐lactoglobulin B, phosphorylase b, and trypsinogen), different dynamic processes of phospholipid–protein interactions were exhibited. The type of phospholipids played an important role in the dynamic process of phospholipid–protein interaction, as noted by the use of zwitterionic phospholipid (phosphatidylcholine) and acidic phospholipid (phosphatidylserine). Mechanisms involved in these interactions were discussed by monitoring the dynamic processes in this study.
Application of a geographic information system to explore associations between air pollution and micronucleus frequencies in African American children and adults
Authors: Huen Karen , Gunn Laura , Duramad Paurene , Jeng Michael , Scalf Russell , Holland Nina
Published: January 2006

Exposure to air pollution has been associated with adverse respiratory and cardiovascular health outcomes in both children and adults. In this study, we used geographic information systems (GISs) to explore possible associations between chromosomal damage in 65 African American children and their mothers from Oakland, California, and both proximity to traffic and regional ozone levels. Study participants were interviewed at the Healthy Child Clinic of Children's Hospital, Oakland, and their blood and buccal cells were collected for assessment of chromosomal damage by the micronucleus (MN) assay. Regional ozone levels, which decreased from April to November with a secondary peak in late summer, were highly correlated with season by month (r = −0.84, P = 0.02) and strongly associated with MN frequency (frequency ratio (FR): 3.37, 95% confidence interval (CI): 1.30–8.72) in both cell types of children and adults. Additionally, MN frequencies were modestly associated with individual measures of traffic density in children (FR = 2.45, 95% CI= 0.86–7.10), but not in adults; this suggests a greater vulnerability to traffic‐related air pollution in children. Smoking in the household also increased MN frequency in the lymphocytes of children (FR: 1.13, 95%CI: 1.01–1.24) and adults (FR: 1.06, 95%CI: 0.99–1.13), whereas vitamin use in adults decreased MN frequency in both lymphocytes and buccal cells (FR: 0.17, 95%CI: 0.02–1.31; FR: 0.18, 95%CI: 0.03–1.18, respectively). Our data indicate that GIS‐generated measures of traffic density for individual households augment regional ozone monitoring data used to assess effects of air pollution. This approach helped to demonstrate elevated cytogenetic damage in exposed minority children. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Searching PubMed for molecular epidemiology studies: The case of chromosome aberrations
Authors: Ugolini Donatella , Neri Monica , Knudsen Lisbeth E. , Bonassi Stefano , Merlo Domenico Franco
Published: January 2006

The available tools for searching literature in the field of Molecular Epidemiology are largely unsatisfactory. To identify major problems in retrieving information on this discipline, we comment here on the results of a literature search on cytogenetic biomarkers in children exposed to environmental pollutants. The search, done on the PubMed/MedLine database, was based on a strategy combining descriptors listed in the PubMed Medical Subject Headings (MeSH) Thesaurus and other available tools (free text or phrase search tools). 178 articles were retrieved by searching the period from January 1, 1980 to November 30, 2004. Only 2 of the 178 articles were indexed by the MeSH term “Epidemiology, molecular” (introduced in 1994) and 30 of 178 by the MeSH term “Biological markers” (introduced in 1989). The case of chromosome aberration (CA) was emblematic of the problem: 44 of 78 articles (56.4%) were not pertinent to the search. The reasons for this poor performance are reported and discussed. Authors and indexers may be able to improve the efficiency of article retrieval in the field of molecular epidemiology by using relevant terms in the title and abstract. This may suggest appropriate MeSH terms to the indexers for the indexing process. As regards the difficulty in identifiyng population studies using CA, the introduction of a specific MeSH term for chromosome aberrations when used as a biomarker would improve the search process. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Quercetin reduces chromosome aberrations induced by atrazine in theAllium cepatest
Authors: Mastrangelo Sabina , Tomassetti Massimiliano , Carratù Maria Rosaria , Evandri Maria Grazia , Bolle Paola
Published: January 2006

Quercetin is a widely distributed plant flavonoid possessing a variety of chemical and biological activities, including chelation, free‐radical scavenging, and antioxidant activity. Atrazine is a selective triazine herbicide that has been the subject of an international revision program for human and ecological health risks because of its persistence in the environment. In a previous study, we demonstrated that atrazine was clastogenic in theAllium cepatest. In this present study, we investigated whether quercetin affords protection from the chromosome breaks induced by atrazine. In a preliminary assay, 0.1–20 μg/ml quercetin produced no toxicity or clastogenic activity in theAllium cepatest. Subsequently, we evaluated the effects of 0.5 and 5 μg/ml quercetin on the clastogenicity of 2.5, 5.0, and 7.5 μg/l atrazine. Quercetin (0.5 μg/ml) significantly reduced the frequency of total aberrations induced by 7.5 μg/l atrazine, while both concentrations of quercetin significantly decreased the frequency of fragments induced by 7.5 μg/l atrazine. The results of this study indicate that plant flavonoids such as quercetin may protect against the genotoxic effects of atrazine. Efforts to understand the extent to which plant flavonoids influence the biological activities of genotoxicants and the mechanisms involved in the interactions could help to better discern the advantages and disadvantages of their use and to clarify their possible protective role against pollutants. Environ. Mol. Mutagen., 2006 © 2006 Wiley‐Liss, Inc.
No association of endometriosis with galactose‐1‐phosphate uridyl transferase mutations in a Chinese population
Authors: He Chunni , Song Yanfeng , He Xiaoyu , Zhang Wenju , Liao Lianming
Published: January 2006

The linkage between endometriosis and galactose‐1‐phosphate uridyl transferase gene (GALT) mutations is controversial. In this study, the prevalence of the most common GALT mutations, Q188R and N314D, was assessed in women with endometriosis in a Chinese population. Three hundred twenty five unrelated women with endometriosis were enrolled. Samples of umbilical cord blood obtained from 310 female newborn infants were used as population controls. Genomic DNA isolated from endometriosis patients and controls were subjected to multiple polymerase chain reactions to determine the Q188R and N314D mutations. There was no significant difference in the frequencies of the Q188R and N314D mutations between endometriosis patients and controls. The endometriosis patients were further divided into subgroups of stage III and IV disease, but still no statistically significant differences were observed in the frequency of the Q188R and N314D mutations between any of these groups and the controls. These findings suggest that Q188R and N314D mutations are not likely to be associated with an increased risk of endometriosis among Chinese Women. Environ. Mol. Mutagen., 2006 © 2006 Wiley‐Liss, Inc.
Solar photocatalytic degradation of groundwater contaminated with petroleum hydrocarbons
Authors: Cho Il‐Hyoung , Kim Lee‐Hyung , Zoh Kyung‐Duk , Park Jae‐Hong , Kim Hyun‐Yong
Published: January 2006

To evaluate the potential use for ex situ remediation, a solar‐driven, photocatalyzed reactor system was constructed and applied to the treatment of groundwater contaminated with benzene, toluene, ethylbenzene, and xylene (BTEX) and total petroleum hydrocarbons (TPHs) near a gas station using selected advanced oxidation processes such as H2O2/solar light, TiO2 slurry/solar light, and immobilized TiO2/solar light. Groundwater samples containing BTEX and TPH, loaded with H2O2 or slurry and immobilized TiO2 catalyst, were exposed to solar light (37° N and 128° E) in winter with an average intensity of 1.6 mW/cm2 measured at 365 nm. Whereas the solar light/TiO2 slurry system achieved >70% degradation of BTEX and TPH within 4 h, the solar light/immobilized TiO2 and solar light/H2O2 systems did not show significant removal within the same time. However, both TiO2 slurry and immobilized systems were able to reduce BTEX and TPH levels effectively if H2O2 (10 mM) was added. The degradation rates of low molecular weight gasoline (BTEX) and n‐alkanes ranging from C10 to C15 were higher than those of n‐alkanes ranging from C16 to C20. The removal efficiency of BTEX and TPH in the groundwater samples also increased with a larger solar collector area of the reactor. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Some indicators of socio‐economic status may not be reliable and use of indices with these data could worsen equity
Authors: Onwujekwe Obinna , Hanson Kara , Fox‐Rushby Julia
Published: January 2006

Socio‐economic status (SES) indices are increasingly being used to characterise (in)equity, with the assumption that SES indices are reliable. However, the accuracy of such SES indices is questionable if they are unreliable. We examined the inter‐rater and test–retest reliability of a range of indicators commonly used to generate SES indices as well as the composite SES indices. Results from research in southeast Nigeria showed considerable variation, with some indicators having only low to moderate reliability (reliability coefficients 0.25–0.77). Inter‐rater and test–retest reliability of SES indices was 0.63 in both cases. Many households were misclassified because of the unreliable SES indices. Analyses of the distribution of resources based on such indicators could lead to inaccuracies in benefit incidence estimates and policy decisions based on low to moderately reliable SES indicators could worsen equity in access to and use of resources. Greater rigour is needed in conceptualising as well as undertaking SES measurements. Copyright © 2006 John Wiley & Sons, Ltd.
Non‐linearity in the cost‐effectiveness frontier
Authors: Lord Joanne , Laking George , Fischer Alastair
Published: January 2006

Conventional cost‐effectiveness decision rules rely on the assumptions that all health care programmes are divisible and exhibit constant returns to scale for a homogeneous population; hence, the path between adjacent programmes on a cost‐effectiveness frontier must be linear. In this paper we build a framework to analyse non‐linear ‘expansion’ paths. We model the impact of two key sources of non‐linearity: economies of scale or scope in the production of health care; and prioritisation of patients who are most likely to benefit from more expensive and more effective treatments. We conclude that the expansion path might be linear, convex or concave, depending on the situation. The path might also exhibit vertical discontinuity due to fixed costs or horizontal discontinuity due to indivisibility. The efficiency of resource allocation might be improved by empirical estimation of expansion paths. We discuss the advantages and disadvantages of this approach compared with a standard stratified analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Amino acids as carbon, energy and nitrogen sources for Penicillium camembertii
Authors: Adour Lydia , Aziza Majda , Couriol Catherine , Amrane Abdeltif
Published: January 2006

Three groups of amino acids were previously characterized on their ability to be assimilated as carbon source by Penicillium camembertii. In view of a deeper understanding of their metabolic behaviour, growth of P. camembertii on glucose, the limiting substrate, and an amino acid was examined in batch culture. Amino acids from the first group (Cys, His, Lys, Met, Trp and Val) are convenient nitrogen sources, but cannot be assimilated as carbon sources. However, they are also dissimilated, namely used for energy supply by oxidation into CO2, during stationary phase, after glucose depletion, as shown for lysine; and the corresponding nitrogen was released as ammonium. Growth exhibited diauxic behaviour for the second group of amino acids (Arg, Leu), since they can be assimilated as carbon sources, in addition to their assimilation as nitrogen sources, but only after glucose depletion, as shown for arginine. A clear differentiation between the assimilated and the dissimilated carbon was demonstrated for the third group of amino acids (Ala, Asp, Glu, Gly, Pro, Ser, Thr); it was shown that the carbon from glutamic acid was assimilated, while the carbon from glucose was dissimilated. Copyright © 2006 Society of Chemical Industry
Mathematical modeling of the batch fermentation of Zoogloea sp. GY3 used for synthesizing polyhydroxyalkanoates
Authors: Yang JinShui , Huang JianXin , Ni JinRen
Published: January 2006

A mathematical model that describes strain growth, product formation and medium consumption is used to predict the performance of batch fermentation of Zoogloea sp. GY3, screened from activated sludge. Zoogloea sp. GY3 is useful in synthesizing polyhydroxyalkanoates (PHAs). The model is based on the Logistic equation for microorganism growth, the Luedeking–Piret equation for production of PHAs and a Luedeking–Piret‐like equation for sucrose consumption, and appears to provide a reasonable description of the behavior of each parameter during the growth phase. The results show that the production of PHAs is growth‐associated, and the model predictions are in satisfactory agreement with measured data. Copyright © 2006 Society of Chemical Industry
Compression of fluorescence microscopy images based on the signal‐to‐noise estimation
Authors: Bernas Tytus , Asem Elikplimi K. , Robinson J. Paul , Rajwa Bartek
Published: January 2006

Modern microscopic techniques like high‐content screening (HCS), high‐throughput screening, 4D imaging, and multispectral imaging may involve collection of thousands of images per experiment. Efficient image‐compression techniques are indispensable to manage these vast amounts of data. This goal is frequently achieved using lossy compression algorithms such as JPEG and JPEG2000. However, these algorithms are optimized to preserve visual quality but not necessarily the integrity of the scientific data, which are often analyzed in an automated manner. Here, we propose three observer‐independent compression algorithms, designed to preserve information contained in the images. These algorithms were constructed using signal‐to‐noise ratio (SNR) computed from a single image as a quality measure to establish which image components may be discarded. The compression efficiency was measured as a function of image brightness and SNR. The alterations introduced by compression in biological images were estimated using brightness histograms (earth's mover distance (EMD) algorithm) and textures (Haralick parameters). Furthermore, a microscope test pattern was used to assess the effect of compression on the effective resolution of microscope images. Microsc. Res. Tech. 69:1–9, 2006. © 2006 Wiley‐Liss, Inc.
Image adaptive point‐spread function estimation and deconvolution for in vivo confocal microscopy
Authors: Von Tiedemann M. , Fridberger A. , Ulfendahl M. , De Monvel J. Boutet
Published: January 2006

Visualizing deep inside the tissue of a thick biological sample often poses severe constraints on image conditions. Standard restoration techniques (denoising and deconvolution) can then be very useful, allowing one to increase the signal‐to‐noise ratio and the resolution of the images. In this paper, we consider the problem of obtaining a good determination of the point‐spread function (PSF) of a confocal microscope, a prerequisite for applying deconvolution to three‐dimensional image stacks acquired with this system. Because of scattering and optical distortion induced by the sample, the PSF has to be acquired anew for each experiment. To tackle this problem, we used a screening approach to estimate the PSF adaptively and automatically from the images. Small PSF‐like structures were detected in the images, and a theoretical PSF model reshaped to match the geometric characteristics of these structures. We used numerical experiments to quantify the sensitivity of our detection method, and we demonstrated its usefulness by deconvolving images of the hearing organ acquired in vitro and in vivo. Microsc. Res. Tech. 69:10–20, 2006. © 2006 Wiley‐Liss, Inc.
NADPH‐diaphorase activity in the superficial layers of the superior colliculus of rats during aging
Authors: Díaz Florentina , Villena Alicia , Vidal Lourdes , Moreno Mercedes , De Vargas Ignacio Pérez
Published: January 2006

Neurons in the superficial layers of the superior colliculus are key elements in the visual system of rodents since they receive extensive afferent projections from retinal ganglion cells. The NADPH‐diaphorase histochemical technique was used to detect differences in neuronal nitric oxide synthase (nNOS) in the superficial layers of the superior colliculus (sSC) of young adult (3 months) and aged (24 and 26 months) rats. The orientation of the dendritic processes of NADPH‐diaphorase‐positive neurons, cross‐sectional area, and number of neurons per mm2 were analyzed. NADPH‐d histochemistry revealed a high number of NADPH‐d‐positive cells in the stratum zonale and stratum griseum superficiale in adult and aged animals. NADPH‐d‐positive neurons were classified into the following morphological types: marginal, horizontal, pyriform, narrow‐field vertical, wide‐field vertical, and stellate. During aging, narrow field vertical and wide field vertical neurons present somatic atrophy and an increase in dendritic processes with dorsoventral orientation, whereas wide field vertical neurons show a decrease in those with lateromedial orientation. Marginal neurons undergo somatic hypertrophy at 26 months when compared with those at 3 months. The remaining types of neurons do not undergo size changes. Finally, the number of NADPH‐d‐positive neurons per mm2 in the various types of morphology does not significantly change with age. It is suggested to be likely that the aging process in the nitrergic neurons of the sSC does not lead to significant changes in the synthesis of NO from the constitutive NOS isoforms. Microsc. Res. Tech. 69:21–28, 2006. © 2006 Wiley‐Liss, Inc.
Arrangement and fine structure of collagen fibrils in the decidualized mouse endometrium
Authors: Carbone Karin , Pinto Nilda M.P. , Abrahamsohn Paulo A. , Zorn Telma M.T.
Published: January 2006

The adaptations of the mouse uterus to pregnancy include extensive modifications of the cells and extracellular matrix of the endometrial connective tissue that surround the embryos. Around each implanted embryo this tissue redifferentiates into a transient structure called decidua, which is formed by polygonal cells joined by intercellular junctions. In the mouse, thick collagen fibrils with irregular profile appear in decidualized areas of the endometrium but not in the nondecidualized stroma and interimplantation sites. The fine organization of these thick fibrils has not yet been established. This work was addressed to understand the arrangement and fine structure of collagen fibrils of the decidua of pregnant mice during the periimplantation stage. Major modifications occurred in collagen fibrils that surrounded decidual cells: (1) the fibrils, which were arranged in parallel bundles in nonpregnant animals, became organized as baskets around decidual cells; (2) very thick collagen fibrils with very irregular profiles appeared around decidual cells. Analysis of replicas and serial sections suggests that the thick collagen fibrils form by the lateral aggregation of thinner fibrils to a central fibril resulting in very irregular profile observed in cross sections of thick fibrils. The sum of modifications of the collagen fibrils seem to represent an adaptation of the endometrium to better support the decidual cells while they hold the embryos during the beginning of their development. The deposition of thick collagen fibrils in the decidua may contribute to form a barrier that impedes leukocyte migration within the decidua, preventing immunological rejection of genetically dissimilar embryonic tissues. Microsc. Res. Tech. 69:36–45, 2006. © 2006 Wiley‐Liss, Inc.
Effects of aging and HIF‐1α deficiency on permeability of hippocampal vessels
Authors: Ueno Masaki , Tomita Shuhei , Nakagawa Toshitaka , Ueki Masaaki , Iwanaga Yasuyuki , Ono Jun‐Ichiro , Onodera Masayuki , Huang Cheng‐Long , Kanenishi Kenji , Shimada Atsuyoshi , Maekawa Nobuhiro , Sakamoto Haruhiko
Published: January 2006

We examined age‐related changes in the blood–brain barrier (BBB) of neural cell‐specific hypoxia inducible factor‐1α (HIF‐1α) deficient mice, which showed hydrocephalus with neuronal cell loss, to investigate an effect of neural cell‐specific HIF‐1α deficiency or hydrocephalus on vascular function. Vascular permeability of horseradish peroxidase (HRP) and binding of cationized ferritin (CF) particles to the endothelial cell luminal surface, as a marker of glycocalyx, were investigated. The thickness of CF‐labeled glycocalyx was significantly decreased in the cortex in mutant mice compared with that of control mice, although it was not paralleled by increased vascular permeability. In addition, strong staining for HRP was seen around vessels located along the hippocampal fissure in 24‐month‐old mutant mice. The reaction product of HRP appeared in an increasing number of the endothelial cell abluminal vesicles and within the thickened basal lamina of arterioles in the hippocampus, showing increased vascular permeability. There were no leaky vessels in 10‐week‐old mutant mice or 10‐week‐old and 24‐month‐old control mice. These findings suggest the necessity of two factors, aging and hydrocephalus, for BBB dysfunction in HIF‐1α deficient mice. Microsc. Res. Tech. 69:29–35, 2006. © 2006 Wiley‐Liss, Inc.
Dynamic‐SIMS imaging and quantification of inorganic ions in frozen‐hydrated plant samples
Authors: Dérue Cedric , Gibouin David , Demarty Maurice , Verdus Marie‐Claire , Lefebvre Fabrice , Thellier Michel , Ripoll Camille
Published: January 2006

We present here SIMS images of the distribution of inorganic cations (Na, K, Mg and Ca) in frozen‐hydrated samples of three plant species, ivy, camomile, and flax. The samples were cryofixed using fast plunge‐freezing. Stigmatic images were obtained, at 100 K, under dynamic SIMS conditions by fast atom bombarding (FAB). Even though the images obtained with the frozen‐hydrated plant samples are still not of upper quality, they show that the method used to prepare these samples preserves existing ionic gradients between the outer and the inner part of the cells, between adjacent cells, including cells with the same type of differentiation, and between tissues. We also describe the quantification of the relative proportions of the ions in the vacuoles of flax. The reasonable accuracy achieved for quantification of the vacuole ion ratios permitted to show (i) that radial gradients of ion ratios in hypocotyls change when the plant is becoming older and (ii) that large differences may exist between adjacent cortical cells of the same type. The role of these substantial differences in vacuole ion balance ratios is a largely unexplored issue in plant physiology. Microsc. Res. Tech. 69:53–63, 2006. © 2006 Wiley‐Liss, Inc.
Antennal and Cephalic organelles in the social wasp Paravespula germanica (Hymenoptera, Vespinae): Form and possible function
Authors: Agmon Ifaat , Plotkin Marian , Ermakov Natalya Y. , Barkay Zahava , Ishay Jacob S.
Published: January 2006

This paper deals with hairs and organelles present on the head and antennae of the German wasp, Paravespula germanica, and their possible role in sensing the physical and chemical ambience, as well as in intercommunicating both while in flight outside or in the nest. Via scanning electron microscope photography, we detected on the frons plate of the wasp's head, hairs that were about 300 μm long and comprised the longest hairs on the body of the wasps. Additionally, the two antennae bore along their entire length photoreceptors, placoids, campaniforms, trichoids, and agmons. These organelles are located at high but variable density along the antennal segments. The paper provides the dimensions of each of the mentioned organelles, and discusses the possible functions of the organelles as well as of the hairs on the frons. Photographs taken via atomic force microscope reveal that the epicuticle of the antenna is of two typical shapes; one, bearing both longitudinal stripes as well as transverse bands that are about 1 μm in width, and a second granulated form. Conceivably, the wasp uses the various organelles mentioned to communicate with its mates that are some distance away, somewhat like the use of radar by humans. Microsc. Res. Tech. 69:46–52, 2006. © 2006 Wiley‐Liss, Inc.
Interembryonic regions of the uterus of the viviparous lizard Mabuya brachypoda (Squamata: Scincidae)
Authors: Uribe‐Aranzábal Mari Carmen , Hernández‐Franyutti Arlette , Guillette Louis J.
Published: January 2006

Analysis of the structure and physiology of the uterine incubation chambers of viviparous squamates has provided insight concerning adaptations for gestation. However, the literature addressing the biology of the interembryonic regions of the uterus is very limited, presumably because it has been assumed that this area has little role in the development and support of embryos in viviparous squamates. This study was undertaken to examine the histology of the interembryonic regions of Mabuya brachypoda, a viviparous lizard with microlecithal ova and consequently substantial matrotrophic activity. The incubation chambers are oval, distended zones of the uterus, adjacent to the interembryonic regions. The wall of the interembryonic regions includes: mucosa, formed by a cubodal or columnar epithelium with ciliated and nonciliated cells, and a lamina propria of vascularized connective tissue containing abundant acinar glands; myometrial smooth muscle consisting of inner circular and outer longitudinal layers; and serosa. The segment of the interembryonic region adjacent to the incubation chamber forms a transitional segment that displays folds of the mucosa that protrude into the uterine lumen. The limit of the incubation chamber is well defined by the long mucosal folds of the transitional segment. Long and thin extensions of extraembryonic membranes are present in the lumen of the transitional segment, outside of the incubation chamber region. The presence of abundant uterine glands and extraembryonic membranes in the interembryonic regions during gestation suggests uterine secretory activity and histotrophic transfer of nutrients to embryos in these regions. J. Morphol. © 2006 Wiley‐Liss, Inc.
Optimized clinical T2 relaxometry with a standard CPMG sequence
Authors: Pell Gaby S. , Briellmann Regula S. , Waites Anthony B. , Abbott David F. , Lewis David P. , Jackson Graeme D.
Published: January 2006

Purpose

To optimize the accuracy and precision of T2 measurements using the standard Carr‐Purcell‐Meiboom‐Gill (CPMG) sequence. T2 values obtained with this technique are normally sensitive to imperfect refocusing due to the formation of unwanted stimulated echoes.

Materials and Methods

Modifications are made to the refocusing slice selection width and the interleaving scheme. A widened refocusing slice improves the uniformity of the refocusing flip angle across the slice. A slow spin echo acquisition provided “gold standard” T2 values. Repeated T2 measurements in phantom and human studies are used to compare the accuracy and precision of the optimized and non‐optimized CPMG implementations.

Results

The required slice thickness ratio between refocusing and excitation slice widths is found to be 3:1 for typical optimized radiofrequency pulses. T2 values obtained using this optimized implementation more closely correspond to “gold standard” values. Repeated T2 measurements indicate significantly improved correspondence between data and model. A reduction in the fitting error of approximately 70% is demonstrated for phantoms.

Conclusion

We demonstrate that a relatively simple change to the CPMG relaxometry sequence parameters from the default setup yields significant improvements in the accuracy and precision of T2 measurements. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Hepatocellular carcinoma missed on gadolinium enhanced MR imaging, discovered in liver explants: Retrospective evaluation
Authors: Karadeniz‐Bilgili Mirace Y. , Braga Larissa , Birchard Katherine R. , Gerber David , Firat Zeynep , Woosley John T. , Shrestha Roshan , Semelka Richard C.
Published: January 2006

The main purpose of this study was to determine if hepatocellular carcinomas (HCCs) missed on prospective magnetic resonance (MR) study could be identified on retrospective MR analysis, and to determine the cause for misdiagnosis. Among 555 patients who underwent liver transplantation between 1993 and 2004, 279 were imaged with MR imaging and four of these revealed HCCs in explanted livers that were not reported on prospective MR reading. The main cause of missed lesions were suboptimal image quality due to inability of patients to suspend respiration; other causes were HCC misinterpreted as high‐grade dysplastic nodule and isoenhancement of HCC on early phase images. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
A parallel approach to STAP implementation for fMRI data
Authors: Thompson Elizabeth A.
Published: January 2006

Purpose

To exploit the capabilities of parallel processing in applying the space‐time adaptive processing (STAP) algorithm, previously explored on a small scale for functional magnetic resonance imaging (fMRI) applications, to conventional size fMRI data sets.

Materials and Methods

STAP is a two‐dimensional filter that is able to locate fMRI activations in both space and frequency. It is applied here for the construction of brain activation maps in fMRI using Visual Age® C, incorporating Engineering and Scientific Subroutine Library (ESSL®) functions, compiled in 64‐bit, and executed on an IBM SP supercomputer.

Results

Computer simulations incorporating actual MRI noise indicate that STAP, incorporated using the method of steepest descent, is feasible on conventional size data sets and exhibits an improvement in detecting activations over the more traditional cross correlation method of fMRI analysis when the response is unknown.

Conclusion

STAP is feasible on traditional size fMRI data sets and useful in elucidating spatial and temporal connectivity. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Repeatability of functional MRI for conformal avoidance radiotherapy planning
Authors: Garcia‐Alvarez Roberto , Liney Gary P. , Beavis Andrew W.
Published: January 2006

Purpose

To establish the repeatability of functional magnetic resonance imaging (fMRI) examinations in order to develop an appropriate margin for functional organs at risk (fOAR) in the radiotherapy planning process.

Materials and Methods

This work investigates the variability of motor cortex activation in the left and right hemispheres of 15 normal subjects. The uncertainty of the absolute position and volume of the activation was determined for each volunteer by repeating the fMRI examination three times in a single scan session.

Results

Our study proposes the use of 2.9 mm and 2.2 mm margins for the left and right motor cortices, respectively.

Conclusion

From the sample of 15 volunteers we established an appropriate planning margin that is considered to represent the uncertainty in spatially measuring the fOAR for a single fMRI examination. The work will be of interest to anyone investigating the clinical robustness of fMRI. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Feasibility of k‐t BLAST technique for measuring “seven‐dimensional” fluid flow
Authors: Marshall Ian
Published: January 2006

Purpose

To investigate the feasibility of rapid MR measurement of “seven‐dimensional” (three velocity components, three dimensions, and time) fluid flow using the k‐t Broad‐use Linear Acquisition Speed‐Up Technique (BLAST).

Materials and Methods

Complete k‐space data were acquired for pulsatile fluid flow in a model of a stenosed carotid bifurcation. The data was subsampled to simulate “training” and “accelerated acquisition” data for reconstruction using k‐t BLAST.

Results

Flow waveforms estimated from k‐t BLAST reconstructions were in good agreement with those measured from the full data set for overall speedup factors up to approximately four times when slice‐by‐slice undersampling in ky was used. Accuracy was better than 25 mm/second or 7% (root‐mean‐square error) for individual time frames under these conditions. Flow patterns in the plane of symmetry, near the bifurcation, and in the stenosis were also in good agreement with those reconstructed from the full data set. Improved performance was obtained from undersampling in both ky and kz, when acceleration factors up to 12 times gave acceptable results.

Conclusion

The k‐t BLAST technique can be applied to flow quantification, and may make feasible the acquisition of time‐resolved blood flow from extended arterial regions within acceptable examination times. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Toward rapid high resolution in vivo intravascular MRI: Evaluation of vessel wall conspicuity in a porcine model using multiple imaging protocols
Authors: Hillenbrand Claudia M. , Jesberger John A. , Wong Eddy Y. , Zhang Shaoxiong , Chang David T. , Wacker Frank K. , Lewin Jonathan S. , Duerk Jeffrey L.
Published: January 2006

Purpose

To assess magnetic resonance (MR) pulse sequences for high resolution intravascular imaging.

Materials and Methods

Intravascular imaging of the abdominal aorta and iliac arteries was performed in vivo in a porcine model at 1.5 T using catheter‐mounted micro‐receive coils. Ten protocols, including spin‐echo (SE)‐echo planar imaging (SE‐EPI), segmented EPI, half‐Fourier single‐shot turbo spin‐echo (HASTE), fast imaging with steady‐state free precession (TrueFISP), turbo spin‐echo (TSE), and SE acquisition schemes were employed in 13 trials. Images were analyzed by six expert raters with respect to wall‐conspicuity, wall‐to‐lumen/tissue contrast, visible layers of the arterial wall, anticipated clinical usefulness, and overall image quality. Mean differences between sequence‐types were evaluated using analysis of variance (ANOVA) between groups with planned comparisons.

Results

The vessel wall was delineated in almost all protocols. Motion artifacts from physiological and device motion were reduced in fast techniques. The best contrast between the wall and surrounding tissue was provided by a HASTE protocol. Anatomic layers of the vessel wall were best depicted on dark blood T2‐weighted TSE. Overall, TrueFISP was ranked highest on the remaining measures.

Conclusion

Dedicated catheter‐coils combined with fast sequences have potential for in vivo characterization of vessel walls. TrueFISP offered the best overall image quality and acquisition speed, but suffered from the inability to delineate the multiple layers of the wall, which seems associated with dark blood‐ and T2‐weighted contrast. We believe future intra‐arterial trials should proceed from this study in normal artery imaging and initially focus on fast T2‐weighted dark blood techniques in trials with pathology. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Quantitative phase‐contrast flow MRI measurements in the presence of a second vessel closely positioned to the examined vessel
Authors: Lagerstrand Kerstin M. , Vikhoff‐Baaz Barbro , Starck Göran , Forssell‐Aronsson Eva
Published: January 2006

Purpose

To examine the influence of the truncated sampling of k‐space data on the accuracy of phase‐contrast (PC) flow quantifications in the presence of nearby vessels.

Materials and Methods

Computer simulations were performed along with some experimental validations on a flow phantom and a normal subject.

Results

The accuracy of the PC flow quantification decreased when a second vessel was positioned closely to the examined vessel. The effect strongly depended on the peak flow velocity in the second vessel relative to the velocity encoding (venc) level of the MRI acquisition, and on the position and area of the second vessel.

Conclusion

Due to the truncated sampling of the k‐space data, signal leaked from nearby vessels and distorted the PC flow quantification in the examined vessel. The presented results suggest specific experimental conditions to minimize this flow quantification error. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Subjects' expectations in neuroimaging research
Authors: Kirschen Matthew P. , Jaworska Agnieszka , Illes Judy
Published: January 2006

Purpose

To explore subjects' attitudes and expectations concerning the detection and management of incidental findings in neuroimaging research.

Materials and Methods

Healthy control subjects (N = 105) who previously participated in neuroimaging studies in medical and nonmedical settings were surveyed about their expectations and attitudes toward unexpected clinical findings on their research brain scans. We hypothesized that even though the participants consented to a scanning procedure for research purposes alone, they would still expect pathology, if present, to be detected and reported to them.

Results

Fifty‐four percent of participants reported that they expected research scans to detect abnormalities if they existed. Nearly all subjects (>90%) reported that they would want findings communicated to them, and many (59%) preferred this to be done by a physician affiliated with the research team. The participants responded in similar ways whether they were scanned in medical or nonmedical settings.

Conclusion

Clarity about procedures for handling incidental findings when obtaining written and verbal informed consent is essential to ensure that the subjects' expectations are consistent with the purpose and scope of the research. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Magnetic resonance imaging of myocardial infarction using a manganese‐based contrast agent (EVP 1001‐1): Preliminary results in a Dog model
Authors: Storey Pippa , Chen Qun , Li Wei , Seoane Peter R. , Harnish Phillip P. , Fogelson Laura , Harris Kathleen R. , Prasad Pottumarthi V.
Published: January 2006

Purpose

To investigate the MRI characteristics of an intracellular manganese‐based contrast agent, EVP 1001‐1 (Eagle Vision Pharmaceutical Corp.), in a canine model of myocardial infarction.

Materials and Methods

Three dogs were imaged 14–37 days following permanent ligation of the left anterior descending coronary artery (LAD). Measurements of the longitudinal relaxation rate R1 were made prior to EVP 1001‐1 administration (20 μmol/kg i.v.) and for one hour thereafter. Triphenyl tetrazolium chloride (TTC) staining was used to document infarction.

Results

In normal myocardium, EVP 1001‐1 produced a substantial increase in the longitudinal relaxation rate, which remained fairly constant over the postcontrast imaging period (ΔR1= 1.47 ± 0.58 sec−1 (mean ± SD) at 35 minutes, P < 0.05). In the infarct, the response to EVP 1001‐1 was small or negligible (ΔR1= 0.27 ± 0.28 sec−1). This resulted in a significant postcontrast difference in relaxation rate between normal and infarcted tissue (R1(normal) − R1(infarct) = 1.08 ± 0.26 sec−1, P < 0.05). The infarct remained clearly delineated in all animals throughout the steady‐state imaging period, and qualitatively matched TTC results.

Conclusion

The persistent enhancement pattern revealed by MRI following EVP 1001‐1 administration may be beneficial for identifying and characterizing myocardial infarction. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Monoclonal antibodies to distinct regions of human myelin proteolipid protein simultaneously recognize central nervous system myelin and neurons of many vertebrate species
Authors: Greenfield Edward A. , Reddy Jayagopala , Lees Andrew , Dyer Charissa A. , Koul Omanand , Nguyen Khuong , Bell Shannon , Kassam Nasim , Hinojoza Julian , Eaton Mary Jane , Lees Marjorie B. , Kuchroo Vijay K. , Sobel Raymond A.
Published: January 2006

Myelin proteolipid protein (PLP), the major protein of mammalian CNS myelin, is a member of the proteolipid gene family (pgf). It is an evolutionarily conserved polytopic integral membrane protein and a potential autoantigen in multiple sclerosis (MS). To analyze antibody recognition of PLP epitopes in situ, monoclonal antibodies (mAbs) specific for different regions of human PLP (50–69, 100–123, 139–151, 178–191, 200–219, 264–276) were generated and used to immunostain CNS tissues of representative vertebrates. mAbs to each region recognized whole human PLP on Western blots; the anti‐100–123 mAb did not recognize DM‐20, the PLP isoform that lacks residues 116–150. All of the mAbs stained fixed, permeabilized oligodendrocytes and mammalian and avian CNS tissue myelin. Most of the mAbs also stained amphibian, teleost, and elasmobranch CNS myelin despite greater diversity of their pgf myelin protein sequences. Myelin staining was observed when there was at least 40% identity of the mAb epitope and known pgf myelin proteins of the same or related species. The pgf myelin proteins of teleosts and elasmobranchs lack 116–150; the anti‐100–123 mAb did not stain their myelin. In addition to myelin, the anti‐178–191 mAb stained many neurons in all species; other mAbs stained distinct neuron subpopulations in different species. Neuronal staining was observed when there was at least approximately 30% identity of the PLP mAb epitope and known pgf neuronal proteins of the same or related species. Thus, anti‐human PLP epitope mAbs simultaneously recognize CNS myelin and neurons even without extensive sequence identity. Widespread anti‐PLP mAb recognition of neurons suggests a novel potential pathophysiologic mechanism in MS patients, i.e., that anti‐PLP antibodies associated with demyelination might simultaneously recognize pgf epitopes in neurons, thereby affecting their functions. © 2006 Wiley‐Liss, Inc.
Inhibitors of the α‐ketoglutarate dehydrogenase complex alter [1‐13C]glucose and [U‐13C]glutamate metabolism in cerebellar granule neurons
Authors: Santos Sónia Sá , Gibson Gary E. , Cooper Arthur J.L. , Denton Travis T. , Thompson Charles M. , Bunik Victoria I. , Alves Paula M. , Sonnewald Ursula
Published: January 2006

Diminished activity of the α‐ketoglutarate dehydrogenase complex (KGDHC), an important component of the tricarboxylic acid (TCA) cycle, occurs in several neurological diseases. The effect of specific KGDHC inhibitors [phosphonoethyl ester of succinyl phosphonate (PESP) and the carboxy ethyl ester of succinyl phosphonate (CESP)] on [1‐13C]glucose and [U‐13C]glutamate metabolism in intact cerebellar granule neurons was investigated. Both inhibitors decreased formation of [4‐13C]glutamate from [1‐13C]glucose, a reduction in label in glutamate derived from [1‐13C]glucose/[U‐13C]glutamate through a second turn of the TCA cycle and a decline in the amounts of γ‐aminobutyric acid (GABA), aspartate, and alanine. PESP decreased formation of [U‐13C]aspartate and total glutathione, whereas CESP decreased concentrations of valine and leucine. The findings are consistent with decreased KGDHC activity; increased α‐ketoglutarate formation; increased transamination of α‐ketoglutarate with valine, leucine, and GABA; and new equilibrium position of the aspartate aminotransferase reaction. Overall, the findings also suggest that some carbon derived from α‐ketoglutarate may bypass the block in the TCA cycle at KGDHC by means of the GABA shunt and/or conversion of valine to succinate. The results suggest the potential of succinyl phosphonate esters for modeling the biochemical and pathophysiological consequences of reduced KGDHC activity in brain diseases. © 2006 Wiley‐Liss, Inc.
Optimization of chronic stress paradigms using anxiety‐ and depression‐like behavioral parameters
Authors: Kim Kyoung‐Shim , Han Pyung‐Lim
Published: January 2006

Chronic stress is a risk factor for psychiatric illnesses, such as anxiety and depression disorders. To understand the underlying mechanism regarding how chronic stress triggers such psychiatric dysfunctions, restraint‐based chronic stress models have been attempted in the past. However, total durations of repeated restraint stress and the evaluation time points used after the last restraint application vary from experiment to experiment. One reason for these methodological heterogeneities is related to considerable ambiguity concerning the definition of chronic stress, particularly in animal models. In the present study, we used behavioral traits, anxiety and depression, as stress‐assessment parameters that meet operationally useful requirements for the definition of the chronic stress state. We demonstrate that restraint treatment for 2 or 8 hr daily for 14 days is enough to produce anxiety‐ and depression‐like behaviors, whereas a 2 hr‐10 days restraint was marginally effective. cDNA microarray analysis identified 34 genes in the hippocampus and 72 genes in the amygdala with expression levels that were up‐ or down‐regulated by >2.0‐fold. Among the wide range of genes identified in this analysis, genes required for energy metabolism, signal transduction, transcription, synaptic plasticity, and remodeling of the brain architecture were notable. Our results suggest that the psychiatric criteria of anxiety and depression can be used as chronic stress‐assessment parameters and that a restraint stress paradigm consisting of restraint treatment for 2 or 8 hr daily for 14 days could be used as a prototype paradigm for chronic stress studies. © 2006 Wiley‐Liss, Inc.
Pigment identification of colored drawings from Wuying Hall of the Imperial Palace by micro‐Raman spectroscopy and energy dispersive X‐ray spectroscopy
Authors: Shen Ai Guo , Wang Xiao Hua , Xie Wei , Shen Jing , Li Hua Yuan , Liu Zhen An , Hu Ji Ming
Published: January 2006

Four ancient colored drawings (CDs), namely in black, blue, white and green, of Wuying Hall in the Imperial Palace, China, were analyzed by micro‐Raman spectroscopy (MRS) in combination with energy dispersive X‐ray spectroscopy (EDX) in order to identify the pigments in each case. The pigments lampblack (a pigment based on amorphous carbon), ultramarine blue/lapis lazuli (Na8[Al6Si6O24]Sn), dolomite (CaMg(CO3)2), emerald green (Cu(C2H3O2)2·3Cu(AsO2)2), gypsum (CaSO4·2H2O) were detected in the CDs, and these will be useful with regard to the restoration of the paintings at Wuying Hall. Furthermore, it is important to take into account the dating of some rare pigments, i.e., ultramarine blue and emerald green, in order to validate that there was a fire that destroyed more than 30 houses of Wuying Hall in 1869 (Tong‐Zhi, 8th year of Qing Dynasty). The results demonstrate that micro‐Raman spectroscopy can provide valuable information for the characterization, restoration and preservation of the cultural relic. Copyright © 2006 John Wiley & Sons, Ltd.