bluuebunny/crossref_metadata_2025 huggingface dataset:
DNA repair pathways involved in anaphase bridge formation
Authors: Acilan Ceyda , Potter Douglas M. , Saunders William S.
Published: March 2007

Cancer cells frequently exhibit gross chromosomal alterations such as translocations, deletions, or gene amplifications an important source of chromosomal instability in malignant cells. One of the better‐documented examples is the formation of anaphase bridges—chromosomes pulled in opposite directions by the spindle apparatus. Anaphase bridges are associated with DNA double strand breaks (DSBs). While the majority of DSBs are repaired correctly, to restore the original chromosome structure, incorrect fusion events also occur leading to bridging. To identify the cellular repair pathways used to form these aberrant structures, we tested a requirement for either of the two major DSB repair pathways in mammalian cells: homologous recombination (HR) and nonhomologous end joining (NHEJ). Our observations show that neither pathway is essential, but NHEJ helps prevent bridges. When NHEJ is compromised, the cell appears to use HR to repair the break, resulting in increased anaphase bridge formation. Moreover, intrinsic NHEJ activity of different cell lines appears to have a positive trend with induction of bridges from DNA damage. © 2007 Wiley‐Liss, Inc.
Genetic variation of antigen processing machinery components and association with cervical carcinoma
Authors: Mehta Akash M. , Jordanova Ekaterina S. , van Wezel Tom , Uh Hae‐Won , Corver Willem E. , Kwappenberg Kitty M. C. , Verduijn Willem , Kenter Gemma G. , van der Burg Sjoerd H. , Fleuren Gert J.
Published: March 2007

The antigen processing machinery (APM) plays an important role in immune recognition of virally infected and transformed cells. Defective expression of several APM components is associated with progression and clinical outcome in cervical carcinoma. Genetic variation in the genes encoding APM components is known to be associated with risk of occurrence of several malignancies. However, only limited evidence exists supporting the role of single nucleotide polymorphisms (SNPs) in APM components in cervical carcinoma. We have therefore investigated the occurrence of APM component SNP genotypes and haplotypes in cervical carcinoma. Thirteen coding SNPs in the LMP2, LMP7, TAP1, TAP2, and ERAP1 genes were genotyped in 127 cervical carcinoma patients and 124 controls. Individual genotype and allele distributions were assessed by single‐marker analysis. Effects of various SNP combinations were estimated by haplotype construction and subsequent haplotype interaction analysis. Significant haplotypes were modeled on disease risk. Allele distributions at the LMP7‐145, TAP2‐651, ERAP1‐127, and ERAP1‐730 loci differed significantly between cases and controls with the major allele at the LMP7 and TAP2 loci and the minor allele at both ERAP1 loci associated with increased cervical carcinoma risk. A combination of the two haplotypes spanning these loci was associated with a three‐fold increased risk (OR = 3.024; P << 0.001); approximately 12% of all cervical carcinoma occurrences were attributable to this combination. Our data indicate that combined genetic variation in the TAP2, LMP7, and ERAP1 genes is associated with increased cervical carcinoma risk. © 2007 Wiley‐Liss, Inc.
Application of the Baldrige model for innovation in higher education
Authors: Furst‐Bowe Julie A. , Bauer Roy A.
Published: March 2007

The Malcolm Baldrige Quality guideposts provide a comprehensive model for systematic quality improvement and innovation in colleges and universities.
Innovation in higher education: A case study of the western governors university
Authors: Kinser Kevin
Published: March 2007

Western Governors University shows how both foreseen and unforeseen challenges shape innovative management responses.
Universal design across the curriculum
Authors: Zeff Robbin
Published: March 2007

The concepts of the applied universal design movement have created fresh perspectives on management tasks and opportunities.
A challenging journey: From leadership courses to leadership foundation for higher education
Authors: Middlehurst Robin
Published: March 2007

Creating a new generation of leaders and managers has been the task of the innovative U.K. Leadership Foundation for Higher Education.
Information technology: A contributor to innovation in higher education
Authors: Dodds Ted
Published: March 2007

University administrators can use information technology to drive innovation through focusing institutional purpose and improving business practices.
Innovation in higher education: Implications for the future
Authors: White Susan C. , Glickman Theodore S.
Published: March 2007

This chapter, drawing from the previous chapters, synthesizes potential directions and implications of future innovation in higher education. The focus is on innovation to address critical issues that administrators face today: the adaptability, maturity, cost structure, and efficiency of the institution.
Measuring head and neck cancer symptom burden: The development and validation of the M. D. Anderson symptom inventory, head and neck module
Authors: Rosenthal David I. , Mendoza Tito R. , Chambers Mark S. , Asper Joshua A. , Gning Ibrahima , Kies Merrill S. , Weber Randal S. , Lewin Jan S. , Garden Adam S. , Ang K. Kian , S. Wang Xin , Cleeland Charles S.
Published: March 2007

Background.

The aim of this study was to develop and validate a symptom inventory for patients with head and neck cancer and to assess the occurrence and severity of symptoms, the overall symptom burden, and the interference the symptoms cause in daily life.

Methods.

Items were generated from a comprehensive literature review, our prior work, and focus groups with head and neck cancer patients, symptom researchers, and a multidisciplinary group of head and neck cancer health care workers. We selected 11 provisional head and neck cancer‐specific items for addition to the core M. D. Anderson Symptom Inventory (MDASI), and conducted a cross‐sectional validation study among patients with head and neck cancer.

Results.

Construct validity was established using principal axis factoring with direct oblimin rotation, and tests of concurrent and known‐groups validity were conducted. Two items were dropped because of low severity scores and low frequency of complaint, leaving 9 final head and neck cancer‐specific items. The coefficient α reliabilities were 0.88, 0.83, and 0.92 for the 13 core MDASI items, the 9 head and neck cancer‐specific items, and the 6 interference items, respectively. The most prevalent severe symptoms were problems with mucus, mouth/throat sores, tasting food, difficulty with chewing or swallowing, dry mouth, pain, and fatigue.

Conclusions.

The M. D. Anderson Symptom Inventory‐Head and Neck (MDASI‐HN) is a reliable and valid instrument to measure head and neck cancer symptom burden, and the interference symptoms cause in the major aspects of a patient's daily life. A subset of specifically distressing symptoms was identified, many of which are not included in commonly used head and neck cancer quality of life instruments. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Hydrology of cave drip waters at varying bedrock depths from a karst system in southeastern Australia
Authors: McDonald Janece , Drysdale Russell
Published: March 2007

The study of how cave drip‐water discharge responds to recharge events is fundamental to evaluating the potential of actively forming speleothems as high‐resolution climate archives. Most previous research has focused on caves of the Northern Hemisphere middle latitudes, where recharge is strongly seasonal. Few studies have explored drip‐water behaviour from regions where the expected seasonal rainfall pattern is significantly perturbed on an irregular basis by changing regional atmospheric circulation patterns. Here, we report the results of a 4‐year study of cave drip‐water–climate relationships from two caves in eastern Australia. The discharge of 10 drip sites located beneath bedrock thicknesses of 12, 22 and 45 m was monitored either continuously (using automated infrared sensors) or at discrete approximately monthly intervals and compared with local rainfall and water balance data. The study period traversed two major droughts, including the severe 2002–2003 El Niño. Drips at 12 and 22 m depths responded almost simultaneously to individual recharge events, although the time lag between individual events varied according to the volume of recharge and pre‐event storage. Overall, a steady decline in discharge is evident through the moisture‐deficit period, with increased flows through phases of positive water balance. Speleothems growing at these and similar shallow‐chamber sites have potential for reconstructing palaeo‐rainfall trends at high‐resolution, although the highly variable nature of year‐to‐year recharge would make it difficult to obtain data on a calendrical time‐scale. Drips at 45 m depth did not respond consistently to individual recharge events and displayed hydrological behaviour markedly dissimilar to one another and to the near‐surface drip sites, indicating great complexity in karst architecture and the absence of fissure flow. Although speleothems at this depth may well preserve information on longer‐term rainfall trends, their potential to encode a palaeo‐rainfall variability signal at interannual resolution is poor. Copyright © 2007 John Wiley & Sons, Ltd.
Using economic concepts to inform enrollment management
Authors: DesJardins Stephen L. , Bell Allison
Published: March 2007

This chapter demonstrates how institutional researchers at institutions of higher education can use economic theory for enrollment management.
Preventive effect of rutin on lipids, lipoproteins, and ATPases in normal and isoproterenol‐induced myocardial infarction in rats
Authors: Stanely Mainzen Prince P. , Karthick M.
Published: March 2007

The present study was designed to evaluate the preventive role of rutin on lipids, lipoproteins, and ATPases in normal and isoproterenol (ISO)‐induced myocardial infarction in rats. Rutin (40 and 80 mg/kg) was orally administered to rats for a period of 42 days. After that period, isoproterenol (150 mg/kg) was injected subcutaneously to male wistar rats at an interval of 24 h for 2 days. The weight of heart and the concentrations of total cholesterol, triglycerides, and free fatty acids were increased significantly (p < 0.05), and the concentration of phospholipids was decreased significantly (p < 0.05) in the heart of ISO‐treated rats. ISO‐treated rats also showed a significant increase (p < 0.05) in the levels of total cholesterol, triglycerides, phospholipids, low‐density lipoprotein cholesterol (LDL‐C), and very low‐density lipoprotein cholesterol (VLDL‐C) with a significant decrease (p < 0.05) in high‐density lipoprotein cholesterol (HDL‐C) level in serum. The activities of sodium potassium dependent adenosine triphosphatase (Na+/K+ ATPase) and magnesium‐dependent adenosine triphosphatase (Mg2+ ATPase) were decreased significantly (p < 0.05), and the activity of calcium‐dependent adenosine triphosphatase (Ca2+ATPase) was increased significantly (p < 0.05) in the heart in ISO‐treated rats. Pretreatment with rutin at doses of 40 or 80 mg/kg to ISO‐treated rats showed a significant (p < 0.05) effect in all the parameters studied. Oral administration of rutin to normal rats did not show any significant effect. Thus, the results of our study show that pretreatment with rutin maintained the levels of lipids, lipoproteins, and ATPases in ISO‐induced myocardial infarcted rats. The observed effects might be due to the antioxidant potential of rutin. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:1–6, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20151
Inactivation of phospholipase A2 and metalloproteinase from Crotalus atrox venom by direct current
Authors: Panfoli Isabella , Ravera Silvia , Calzia Daniela , Dazzi Elisa , Gandolfo Simona , Pepe Isidoro M. , Morelli Alessandro
Published: March 2007

To achieve our aim of understanding the interactions between direct current and enzymes in solution, we exposed reconstituted Crotalus atrox venom to direct electric current by immersing two platinum thread electrodes connected to a voltage generator (between 0 and 8 V) into a reaction mixture for a few seconds. Then, we assayed the residual activity of phospholipases A2 (PLA2),metalloproteinases, and phosphodiesterases, abundant in crotaline snake venoms and relevant in the pathophysiology of envenomation, characterized by hemorrhage, pain, and tissue damage. C. atrox venom phospholipase A2 and metalloproteinases were consistently and irreversibly inactivated by direct current (between 0 and 0.7 mA) exposure. In contrast, C. atrox venom phosphodiesterases were not affected. Total protein content and temperature of the sample remained the same. Secretory pancreatic phospholipase A2, homologue to snake venom phospholipases A2, was also inactivated by direct current treatment. In order to understand the structural reasoning behind PLA2 inactivation, circular dichroism measurements were conducted on homogeneous commercial pancreatic phospholipase A2, and it was found that the enzyme undergoes structural alterations upon direct current exposure. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:7–12, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20152
Cloning, tissue expression, and inducibility of CYP 3A79 from sea bass (Dicentrarchus labrax)
Authors: Vaccaro E. , Salvetti A. , Carratore R. Del , Nencioni S. , Longo V. , Gervasi P. G.
Published: March 2007

Multiple members of the CYP3A subfamily have been identified and intensively studied in mammals as they represent prominent CYP enzymes involved in drug metabolism. Also in fish, some CYP3A genes have been identified by cDNA cloning and immunological techniques, but relatively little is known about their function, distribution, and inducibility. In this study, a novel CYP3A, designated as CYP3A79 was isolated from adult male sea bass, an economically valuable species in fisheries. The sea bass CYP3A79 that was cloned contained an open‐reading frame of 1512 bp that encoded a 504 amino acid protein and shared a high‐sequence identity with medaka, killifish, and trout CYP3As. Interestingly, CYP3A79 also shares five of six substrate recognition sites (SRS) with the SRS of other fish CYP3As, suggesting an evolutionary conservation of the function of these enzymes. In this fish, we also investigated the expression of CYP3A79 and its susceptibility to induction by various compounds including clotrimazole and dehydroepiandrosterone, two strong ligands of zebrafish PXR. The expression of CYP3A79 mRNA was detected by RT‐PCR only in the intestine and liver. The immunoblot analysis by antitrout CYP3A27 confirmed the presence of a CYP3A‐like protein in the microsomes of these tissues, but, in addition, a immunoreactive protein with this antibody was also observed in the heart microsomes, suggesting the presence of other CYP3A isoforms in this fish. Accordingly, the southern blot analysis of genomic DNA indicated that multiple CYP 3As may be present in sea bass. All attempts to induce 6β‐testosterone hydroxylase, as a marker of CYP3A79, by dexametasone, 17β‐estradiol, pregnenolone 16α‐carbonitrile, corticosterone, clotrimazole, and dehydroepiandrosterone failed. On the contrary, the administration of 17β‐estradiol, pregnenolone 16α‐carbonitrile, and corticosterone strongly inhibited this activity and, in parallel, reduced the expression of CYP3A79 transcript. Thus, the sea bass CYP3A79 appears to be resistant to induction, suggesting that this enzyme and likely other CYP3As are regulated differently compared to those of mammals. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:32–40, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20153
Galactosamine‐induced hepatotoxic effect and hepatoprotective role of a protein isolated from the herb Cajanus indicus L in vivo
Authors: Manna Prasenjit , Sinha Mahua , Sil Parames C.
Published: March 2007

dd(+)‐Galactosamine is a well‐known experimental hepatotoxin. The present study was conducted to determine the protective role of a 43‐kD protein isolated from the leaves of the herb Cajanus indicus L against dd(+)‐galactosamine (GalN) induced liver damage in mice. Both preventive and curative effects of the protein have been investigated in the study. The protein was administered intraperitoneally at a dose of 2 mg/kg body weight for 4 days before and after GalN intoxication at a dose of 800 mg/kg body weight for 3 days. The increased activities of serum marker enzymes, alanine aminotransferase, and alkaline phosphatase because of GalN administration, were significantly reduced by the protein treatment. The protein also normalized the altered activities of antioxidant enzymes superoxide dismutase, catalase, glutathione reductase, and glutathione‐S‐transferase as well as the levels of cellular metabolites, reduced glutathione, glutathione disulfide, and total thiols. In addition, the enhanced hepatic lipid peroxidation because of GalN intoxication was also effectively inhibited by the protein treatment. Results suggest that GalN caused hepatic damages via oxidative insult and that the protein provided protection through its antioxidant mechanism. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:13–23, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20154
Hemoperitoneum from ruptured cyst in a hyperstimulated ovary: A sonographic mimic of ovarian hyperstimulation syndrome
Authors: Gunabushanam Gowthaman , Mandal Kavita , Lal Suman
Published: March 2007

We report a case of a ruptured cyst in a hyperstimulated ovary that was initially misinterpreted as ovarian hyperstimulation syndrome (OHSS). A 22‐year‐old woman who was on oral clomiphene citrate for primary infertility presented with pain in the lower abdomen, hypotension, and tachycardia. Sonographic examination revealed multiple cysts in both ovaries and free fluid in the abdomen, and the initial diagnosis was OHSS. However, sonographically guided aspiration of free fluid revealed a hemoperitoneum, and the patient underwent emergent surgery. At laparotomy, an actively bleeding ruptured cyst in a hyperstimulated ovary was found to be the cause of the hemoperitoneum. Radiologists must be familiar with the imaging features of this condition to avoid misdiagnosing it as OHSS, because this could potentially delay urgently required surgery. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Resistance and pulsatility index increase in capsular branches of testicular artery: Indicator of impaired testicular microcirculation in varicocele?
Authors: Ünsal Alparslan , Turgut Ahmet Tuncay , Taşkin Füsun , Koşar Uğur , Karaman Can Zafer
Published: March 2007

Purpose.

To evaluate the effect of clinical varicocele on testicular microcirculation using spectral Doppler analysis.

Methods.

Forty‐nine young and healthy volunteers were enrolled in this prospective study. Varicocele grades were determined according to sonographic parameters. Patients with left‐sided clinical varicocele were classified as the patient group (n = 15), while the remaining patients served as controls (n = 34). Spectral Doppler measurements of testicular arteries (peak systolic/end diastolic velocity, resistance index, pulsatility index) were measured from capsular and intratesticular branches.

Results.

No statistically significant difference was found between the Doppler parameters obtained from the intratesticular branches of both testes and the capsular branches of the right testis. On the other hand, in left‐sided clinical varicocele cases, the average resistance index (RI) and pulsatility index (PI) of capsular branches of the left testes (RI, 0.68 ± 0.04; PI, 1.22 ± 0.15) were significantly greater than in the control group (RI, 0.64 ± 0.06; PI, 1.07 ± 0.18) (p < 0.05 and p < 0.01, respectively).

Conclusions.

Increased RI and PI of capsular branches of testicular arteries on spectral Doppler examination may be an indicator of impaired testicular microcirculation in patients with clinical varicocele. Further studies addressing the correlations with sperm counts are needed to determine the cut‐off values for these indices. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
SLIM: A new method for molecular imaging
Authors: Rück A. , Hülshoff CH. , Kinzler I. , Becker W. , Steiner R.
Published: March 2007

We used spectrally resolved fluorescence lifetime imaging (SLIM) to investigate the mitochondria staining dye rhodamine 123 and binding of DAPI to RNA and DNA in cells. Moreover, different components of the photosensitizer Photofrin were resolved in cell cultures by SLIM. To record lifetime images (τ‐mapping) with spectral resolution we used a laser scanning microscope equipped with a spectrograph, a 16 channel multianode PMT, and multidimensional time‐correlated single photon counting. A Ti:Saphir laser was used for excitation or alternatively a ps diode laser. With this system the time‐ and spectral‐resolved fluorescence characteristics of different fluorophores were investigated in cell cultures. As an example, the mitochondria staining dye rhodamine I23 could be easily distinguished from DAPI, which binds to nucleic acids. Also different binding sites of DAPI could be discriminated. This was proved by the appearance of different lifetime components within different spectral channels. Moreover, we were able to detect monomeric and aggregated forms of Photofrin in cells. Different lifetimes could be attributed to the various compounds. In addition, a detailed analysis of the autofluorescence by SLIM could explain changes of mitochondrial metabolism during Photofrin‐PDT. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Rapid hyperspectral fluorescence lifetime imaging
Authors: Beule Pieter De , Owen Dylan M. , Manning Hugh B. , Talbot Clifford B. , Requejo‐Isidro Jose , Dunsby Christopher , Mcginty James , Benninger Richard K.P. , Elson Daniel S. , Munro Ian , John Lever M. , Anand Praveen , Neil Mark A.A. , French Paul M.W.
Published: March 2007

We report a rapid hyperspectral fluorescence lifetime imaging (FLIM) instrument that exploits high‐speed FLIM technology in a line‐scanning microscope. We demonstrate the acquisition of whole‐field optically sectioned hyperspectral fluorescence lifetime image stacks (with 32 spectral bins) in less than 40 s and illustrate its application to unstained biological tissue. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Estimating the active metabolic rate (AMR) in fish based on tail beat frequency (TBF) and body mass
Authors: Ohlberger Jan , Staaks Georg , Hölker Franz
Published: March 2007

Tail beat frequency (TBF) was measured for carp (Cyprinus carpio) and roach (Rutilus rutilus), during steady swimming at five different speeds and for fish of various body masses. A multiple stepwise linear regression analysis resulted in models for the prediction of TBFs depending on swimming speed as an independent variable. Speed explained 72 and 86% of the variance in TBF for carp and roach, respectively. By using these data to predict TBF from speed and substituting values into a model from a previous study that predicts active metabolic rates (AMR) from body mass and swimming speed, we can calculate AMR from only fish mass and TBF. Thus, the derived models can be used to estimate the AMR in fish by measuring TBFs in the field using biotelemetry. The approach presented here is a useful and relatively simple tool for estimating the activity metabolism in free‐swimming fish. In future studies this method should be applied to a larger and more representative sample size to test the applicability and the validity for a broader range of species. J. Exp. Zool. 307A:296–300, 2007. © 2007 Wiley‐Liss, Inc.
Factors that influence VSV‐G pseudotyping and transduction efficiency of lentiviral vectors—in vitro and in vivo implications
Authors: Farley Daniel C. , Iqball Sharifah , Smith Joanne C. , Miskin James E. , Kingsman Susan M. , Mitrophanous Kyriacos A.
Published: March 2007

Pseudotyping viral vectors with vesicular stomatitis virus glycoprotein (VSV‐G) enables the transduction of an extensive range of cell types from different species. We have discovered two important parameters of the VSV‐G‐pseudotyping phenomenon that relate directly to the transduction potential of lentiviral vectors: (1) the glycosylation status of VSV‐G, and (2) the quantity of glycoprotein associated with virions. We measured production‐cell and virion‐associated quantities of two isoform variants of VSV‐G, which differ in their glycosylation status, VSV‐G1 and VSV‐G2, and assessed the impact of this difference on the efficiency of mammalian cell transduction by lentiviral vectors. The glycosylation of VSV‐G at N336 allowed greater maximal expression of VSV‐G in HEK293T cells, thus facilitating vector pseudotyping. The transduction of primate cell lines was substantially affected (up to 50‐fold) by the degree of VSV‐G1 or VSV‐G2 incorporation, whereas other cell lines, such as D17 (canine), were less sensitive to virion‐associated VSV‐G1/2 quantities. These data indicate that the minimum required concentration of virion‐associated VSV‐G differs substantially between cell species/types. The implications of these data with regard to VSV‐G‐pseudotyped vector production, titration, and use in host‐cell restriction studies, are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and structure‐activity relationships of a series of increasingly hydrophobic cationic steroid lipofection reagents
Authors: Gruneich Jeffrey A. , Diamond Scott L.
Published: March 2007

The use of cholesterol‐based cationic lipids and the ability of glucocorticoids to reduce local inflammatory response to lipoplexes motivated an investigation of structure‐activity relationships for cationic steroids. A one‐step synthetic scheme using iminothiolane was developed to link spermine to the 21‐OH position of steroids via an amidine linkage. Five steroids (cortisol, dexamethasone, corticosterone, 11‐deoxycortisol, and 11‐deoxycorticosterone) with increasing hydrophobicity of the parent steroid (Log Pster from 1.51 to 3.01) were conjugated with spermine, formulated with dioleoylphosphatidylethanolamine (DOPE) at DOPE : steroid mole ratios (R) of R = 0.5 to 2, and then complexed with 1 µg enhanced green fluorescent protein (EGFP) plasmid DNA at charge ratios (CR) = 2 to 24 amines per phosphate (0.5 to 6 steroids per phosphate). The resulting 105 different formulations of the cationic steroid series were used to lipofect bovine aortic endothelial cells. Transgene expression data at either 24 or 48 h post‐lipofection for all formulations was collapsed onto master curves when plotted against a single empirical dimensionless parameter, the lipofection index (LI) = CR (Log Pliposome)(Log Pster/|ΔLog P|) [R/(R + 1)] where ΔLog P = Log PDOPE− Log Pster and Log Pliposome is a mole‐weighted average of the DOPE/cationic steroid liposome hydrophobicity. For 7 < LI < 29, the EGFP expression at 24 or 48 h post‐lipofection increased linearly with LI (EGFP ∼0 for LI < 7), but did not increase further for LI > 29, thus providing a predictive design rule based on Log P of the hydrophobic moiety of the cationic steroid lipid. Copyright © 2007 John Wiley & Sons, Ltd.
Erratum: Bare knuckle and better technics: trajectories of access to safe water in history and in the global south
Authors: Crow Ben
Published: March 2007

Bare Knuckle and Better Technics: Trajectories of Access to Safe Water in History and in the Global South. B. Crow. Journal of International Development (19)1: 83–98.

The author would like to include the following reference: Nickson A, Franceys R. 2003. Tapping the Market: The Challenge of Institutional Reform in the Urban Water Sector. Palgrave Macmillan: Basingstoke.
Local histogram correction of MRI spatially dependent image pixel intensity nonuniformity
Authors: Decarli C. , Murphy D. G. M. , Teichberg D. , Campbell G. , Sobering G. S.
Published: March 2007

We describe a computationally straightforward post‐hoc statistical method of correcting spatially dependent image pixel intensity nonuniformity based on differences in local tissue intensity distributions. Pixel intensity domains for the various tissues of the composite image are identified and compared to the distributions of local samples. The nonuniformity correction is calculated as the difference of the local sample median from the composite sample median for the tissue class most represented by the sample. The median was chosen to reduce the effect ers on determining the sample statistic and to allow a sample size small enough to accurately estimate the spatial variance of the image intensity nonuniformity. The method was designed for application to two‐dimensional images. Simulations were used to estimate optimal conditions of local histogram kernel size and to test the accuracy of the method under known spatially dependent nonuniformities. The method was also applied to correct a phantom image and cerebral MRIs from 15 healthy subjects.

Results show that the method accurately models simulated spatially dependent image intensity differences. Further analysis of clinical MR data showed that the variance of pixel intensities within the cerebral MRI slices and the variance of slice volumes within individuals were significantly reduced after nonuniformity correction. Improved brain‐cerebrospinal fluid segmentation was also obtained. The method significantly reduced the variance of slice volumes within individuals, whether it was applied to the native images or images edited to remove nonbrain tissues.

This statistical method was well behaved under the assumptions and the images tested. The general utility of the method was not determined, but conditions for testing the method under a variety of imaging sequences is discussed. We believe that this algorithm can serve as a method for improving MR image segmentation for clinical and research applications.
Multilevel wavelet‐transform encoding in MRI
Authors: Peters Robert D. , Wood Michael L.
Published: March 2007

This paper explores an alternative to standard Fourier MRI called wavelet‐transform encoding. Spatially selective radiofrequency (RF) pulses are used to excite slice profiles in the shape of the wavelet‐basis functions of a discrete wavelet transform. Our implementation on a standard commercial whole body MRI system resolves one spatial dimension through wavelet encoding and orthogonal directions through conventional frequency encoding and rectangular‐slice selection. The wavelet transform is described as a method for multiresolution analysis, and we show how a high resolution MR image can be constructed from lower resolution images, representing the approximation and detail structures of the object. A multiple level architecture of the wavelet reconstruction is described, thereby allowing wavelet‐encoded images to be reconstructed through several modes. Multilevel wavelet‐encoded images of a gel phantom are presented that show comparable image quality to Fourier‐encoded images of similar signal‐to‐noise ratio. However, a chemical‐shift artifact is identified with this particular implementation.
Velocity‐encoded, phase‐difference cine MRI measurements of coronary artery flow: Dependence of flow accuracy on the number of cine frames
Authors: Clarke Geoffrey D. , Hundley W. Gregory , McColl Roderick W. , Eckels Robin , Chaney Dorothy Smith Curtis , Li Hong‐Fang , Peshock Ronald M.
Published: March 2007

Phase‐contrast magnetic resonance imaging (PC‐MRI) can be used to produce multiframe cine flow images of the coronary arteries. Accurate coronary flow measurement requires the elimination of respiratory motion artifacts using k‐space segmentation to acquire the data in a single breath‐hold. However, the duration of the breath‐hold is proportional to the number of cine frames. In the present study, the number of cine frames was varied and the accuracies of the coronary flow measurements were assessed using perivascular US. For the range of flows studied (2 ml/min to 147 ml/min), the correlation coefficients for PC‐MRI and US increased (.70–.98) and the limits of agreement improved (±45 ml · min−1 to ± 10 ml · min−1) as the number of cine frames increased from one to six. The results suggest that the accuracy of breath‐hold cine PC‐MRI measurements of coronary artery flow improves as the number of cine frames increases.
Application of a quantitative model to differentiate benign from malignant breast lesions detected by dynamic, gadolinium‐enhanced MRI
Authors: Kelcz Frederick , Santyr Giles E. , Cron Greg O. , Mongin Steven J.
Published: March 2007

Both benign and malignant breast lesions may exhibit intense contrast enhancement when imaged using gadolinium‐enhanced MRI. We propose a quantitative approach for fitting dynamic signal intensity (SI) data that may distinguish benign from malignant lesions. We studied 78 lesions in 75 women (18 malignancies, 16 fibroadenomas, and 44 other benign breast lesions) to determine the potential of this model for decreasing false‐positive MR results. Twenty‐eight lesions showed no enhancement; all were benign. One lesion showed a complex pattern not amenable to region‐of‐interest analysis and was considered a false positive. SI versus time data for the remaining 49 lesions were fit to the proposed model. We found that one parameter, M, the normalized slope of the SI enhancement profile evaluated at half the maximal signal intensity, seemed to be highly correlated with malignancy and offered improved discrimination between malignant and benign lesions compared to a previously published two‐point slope method.
Segmentation strategies for breast tumors from dynamic MR images
Authors: Lucas‐Quesada Flora Ann , Sinha Usha , Sinha Shantanu
Published: March 2007

This paper describes two semiautomated methods of segmentation of breast tumors from dynamic MR images obtained subsequent to administration of gadopentate dimeglumine. The first method, based on temporal correlation, generates a similarity map from the dynamic scans in which the value of each pixel is determined by its temporal similarity to a reference region of interest. The second method uses multispectral analysis and generates a feature map from a scatterplot of pixel intensities in the pre‐ and postcontrast images. The segmentation methods were tested on malignant and benign breast lesions in 11 patients with a range of tumor volumes and percentage contrast enhancement. The accuracy of both segmentation techniques and reproducibility of the multispectral method were investigated. A comparison of the two methods established that the temporal correlation method was superior based on accuracy, extent of user interaction, and speed of segmentation.
Hepatic parenchymal hyperperfusion abnormalities detected with multisection dynamic MR imaging: Appearance and interpretation
Authors: Ito Katsuyoshi , Honjo Kazumitsu , Fujita Takeshi , Awaya Hitomi , Matsumoto Tsuneo , Matsunaga Naofumi
Published: March 2007

On arterial‐dominant‐phase images in multisection dynamic MR imaging, early‐enhancing areas that are perfusion abnormalities rather than tumor deposit are sometimes encountered. The purpose of this article was to determine the frequency, location, and appearance of these hepatic parenchymal hyperperfusion abnormalities and to discuss possible causes of these abnormalities. Multisection dynamic MR images obtained in 415 patients with suspected hepatobiliary diseases were reviewed for the presence of hyperperfusion abnormalities. A total of 96 hyperperfusion abnormalities were identified in 88 (21%) of 415 patients. They were characterized from their shape, distribution, or location as lobar or segmental (n = 36 [38%]), subsegmental (n = 32 [33%]), or subcapsular (n = 28 [29%]) hyperperfusion abnormalities. Presumable etiologies were considered as follows: (a) compression, obstruction, or ligation of the portal vein; (b) siphoning effect by tumor; (c) aberrent cystic venous drainage; (d) percutaneous ethanol injection; (e) percutaneous needle biopsy; (f) rapid drainage by the subcapsular vein; or (g) cirrhosis or unknown. A significant percentage of patients had hepatic hyperperfusion abnormalities. Familiarity with these hyperperfusion abnormalities on multisection dynamic MR images is important to prevent false‐positive diagnoses.
High resolution MR imaging and localization of laser‐induced thermal injury in the vascular wall
Authors: Ahmad Asif , Roberts Cynthia , Herderick Edward E.
Published: March 2007

With the increasing use of lasers in surgical procedures, there is need for a noninvasive imaging modality to monitor laser–tissue interactions. MRI can be used readily for imaging human anatomy and holds the potential to map laser‐induced thermal injury. This study investigates high resolution T1‐weighted MR imaging of human aorta samples (in vitro) that have been damaged thermally using an argon ion laser and the corresponding histology. High resolution T1‐weighted MR images (voxel size, .156 × .156 × .700 mm) clearly detected residual thermal injury as areas of bright signal intensity. Effective localization of thermal injury was achieved by subtraction of preinjury and postinjury slices with pseudocoloring of positive and negative differences. The results may serve as a basis from which to guide future in vivo studies.
Application of keyhole imaging to interventional MRI: A simulation study to predict sequence requirements
Authors: Duerk Jeffrey L. , Lewin Jonathan S. , Wu Dee H.
Published: March 2007

A wide variety of techniques have been proposed recently to improve the temporal resolution of MRI. These include echo‐planar imaging methods, wavelet encoding, singular value decomposition encoding, and k‐space sharing methods known as „keyhole”︁ imaging. In this work, we use a simulation study to investigate the phase‐encoding ordering and data‐sharing methods required for the application of keyhole imaging to interventional MRI (I‐MRI). The advantages of keyhole imaging over other methods are its simplicity and the use of conventional phase encoding and Fourier transform reconstruction found on virtually all modern MR imagers. Our analysis has predicted that conventional keyhole methods that repeatedly acquire only the center portion of k space, and those that sequentially progress from the center of k space outward, will not meet the combination of temporal and spatial resolution required for tip localization during I‐MRI needle insertion. Instead, acquisitions that acquire both high and low k‐space data, in ranked order, should provide acceptable tip position and needle width accuracy in both temporal and spatial domains for use in I‐MRI.
Cancellation of metal‐induced MRI artifacts with dual‐component paramagnetic and diamagnetic material: Mathematical modelization and experimental verification
Authors: Chauvel Brice , Cathelineau Guy , Balac Stéaphane , Lecerf Jean , De Certaines Jacques D.
Published: March 2007

A mathematical model of dual‐component paramagnetic and diamagnetic material to cancel metal‐induced MRI artifacts was developed and verified experimentally. The magnetization produced by metallic material and then the gradient linearity distortion can be cancelled by using such materials with opposing paramagnetic and diamagnetic properties. This concept of dual‐component materials provides a novel solution to the problem of MRI artifacts.
Automatic removal of extrameningeal tissues from MR images of human brain
Authors: Bedell Barry J. , Narayana Ponnada A.
Published: March 2007

An automatic technique for removal of extrameningeal tissues from MR images of human brain is described. The algorithm is based on the segmentation of images acquired with a fast dual‐echo pulse sequence, which incorporates both fluid attenuation and magnetization transfer contrast for superior brain/extrameningeal tissue contrast compared to conventional MR sequences. Evaluation of this technique using MR images of six volunteers indicates rapid and consistent removal of extrameningeal tissues.
High resolution MR imaging of the bilateral hips with dual phased‐array coil
Authors: Niitsu Mamoru , Mishima Hajime , Miyakawa Shumpei , Itai Yuji
Published: March 2007

We applied dual‐flex coils in a phased‐array configuration to obtain high resolution MR images of the bilateral hips and compared the image quality with non‐phased‐array imaging. Multiple fast spin‐echo images of both hips were obtained in a single acquisition. Two consecutive acquisitions with and without phased‐array capability were performed in 22 hips and a fluid‐filled phantom. The signal‐to‐noise ratio (S/N) enhancement values were calculated. Subjective image analysis was also obtained from three independent reviewers. High quality MR images were obtained using dual‐array coils with a S/N enhancement value of 1.40 for a phantom and 1.83 to 2.22 for subject hips. On subjective analysis, the dual array enhanced delineation of the acetabular labrum, articular cartilage, and retained fluid. The dual array may be of diagnostic value with a higher S/N enhancement and subjective superiority of the images obtained.
MR imaging contrast agents — what's in a name?
Authors: Mitchell Donald G.
Published: March 2007

The purpose of this brief review is to reduce the confusion surrounding the nomenclature of MRI contrast agents. There are several different categories of contrast agents for potential use in human diagnosis and several alternative names for each contrast agent, an array of choices that actually changes over time. This review describes the general process by which these various agents are named, presents one general categorization by which these agents can be considered, and provides a concise table to which readers can refer to identify the proper name to use for each of the agents that has thus far been administered to humans.
Application of contrast agents in the evaluation of stroke: Conventional MR and echo‐planar MR imaging
Authors: Maeda Masayuki , Maley Joan E. , Crosby Daniel L. , Quets Jerome P. , Zhu Ming‐Wang , Lee Ghi Jai , Lawler Gregory J. , Ueda Toshihiro , Bendixen Birgitte H. , Yuh William T. C.
Published: March 2007

The availability of new therapeutic interventions, including neuroprotective agents and endovascular thrombolysis, has given new hope to patients suffering an acute stroke. Early intervention remains a key factor in the effectiveness of these new and traditional treatments. More importantly, the capability to assess the viability and reversibility of the ischemic tissue became essential for better delineation and differentiation of infarcted versus ischemic tissue and patient management. Abnormal MR imaging (MRI) findings during acute stroke usually reflect the underlying pathophysiologic changes, which can be classified into three sequential stages: (a) hypoperfusion, (b) cellular dysfunction and (c) breakdown of the blood‐brain barrier. The first stage is a kinetic phenomenon (not biologic) and, therefore, can be detected immediately. Contrast agents accentuate the abnormal flow kinetics and facilitate the early diagnosis of ischemia using either conventional MRI or newly developed echo‐planar perfusion imaging (EPPI). The demonstration of abnormal arterial or parenchymal enhancement on conventional MRI during acute stroke provides the earliest sign of vascular occlusion/stenosis. EPPI, in contrast, provides information related to microcirculation (< 100 microns) and tissue reserve (cerebral blood volume) that cannot be obtained by conventional angiography and is directly related to the target end‐organ. Further information obtained from both contrast MRI and EPPI may have a predictive value in the clinical outcome of acute stroke patients.
Contrast‐enhanced MR imaging in the evaluation of treatment response and prediction of outcome in multiple sclerosis
Authors: Simon Jack H.
Published: March 2007

MR imaging is becoming increasingly important in the evaluation of multiple sclerosis based on its sensitivity to acute, often subclinical events in the brain and because it provides a basis for measuring the accumulation of disease over time. Contrast‐enhanced MR imaging in particular evaluates disease at the fundamental level of events affecting the blood‐brain barrier. This review emphasizes (a) recent developments in the use of contrast‐enhanced MR imaging as a measure of disease in patient groups and individuals and (b) its emerging role in evaluating new therapies.
Contrast agents in functional MR imaging
Authors: Sorensen A. Gregory , Tievsky Andrew L. , Ostergaard Leif , Weisskoff Robert M. , Rosen Bruce R.
Published: March 2007

Contrast agents have greatly expanded the role of MR imaging (MRI) to allow assessment of physiologic, or “functional,” parameters. Although activation mapping generally does not require contrast agents, other forms of functional MRI, including mapping of cerebral hemodynamics (eg, perfusion imaging), are best done with the use of contrast agents. Serial echo planar images are obtained after bolus injection of lanthanide chelates. Application of susceptibility contrast physics and standard tracer kinetic principles permits generation of relative cerebral blood volume maps. Deconvolution of cerebral blood flow and mean transit time parameters is also possible within technical limitations. By using diffusion and perfusion pulse sequences, an imaging correlate to the ischemic penumbra can be identified. Functional MRI perfusion imaging of intraaxial tumors is analogous to positron emission tomography for delineation of metabolic activity, yet may be even more sensitive to neovascularity and possesses improved image quality. Clinical applications include biopsy site selection and postirradiation follow‐up. Further improvements in data analysis and map generation techniques may improve diagnostic accuracy and utility.
Physiologic measurements by contrast‐enhanced MR imaging: Expectations and limitations
Authors: Roberts Timothy P. L.
Published: March 2007

Contrast‐enhanced magnetic resonance imaging (MRI) offers the opportunity to quantitatively assess physiologic properties of tissue, such as perfusion, blood volume, and capillary permeability. Use of such quantitation potentially allows tissues to be characterized in terms of pathophysiology and to be monitored over time, during the course of therapeutic intervention. The degree to which such quantitation is applicable relies heavily on simplified model descriptions of the tissue space and assumptions relating the signal intensity observed to the contrast agent concentration. This article presents a perspective on the use of quantitative contrast‐enhanced MRI, analysis of the accuracy of derived physiologic parameters, and recommendations for pulse sequence choice.
Assessment of tumor microcirculation: A new role of dynamic contrast MR imaging
Authors: Griebel Jürgen , Mayr Nina A. , De Vries Alexander , Knopp Michael V. , Gneiting Thomas , Kremser Christian , Essig Marco , Hawighorst Hans , Lukas Peter H. , Yuh William T. C.
Published: March 2007

With the advances in MR techniques, information related to tumor microcirculation now can be obtained in the clinical setting. This information can be valuable in the assessment of tumor blood supply/oxygenation status and tumor response to therapy. In this article, we review the tracer‐kinetic modeling for tumor microcirculatory parameters derived from dynamic contrast MR imaging and report several preliminary results from both an animal model and early experience with human tumors. Despite the application of different MR protocols and tracer‐kinetic models, the initial results of these pioneer studies consistently support the role of MR‐derived microcirculatory tumor parameters, in providing prognostic information to assess and predict the response of cancers to cytotoxic therapy.