bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moving in the right direction—Nanoimaging in cancer cell motility and metastasis
Authors: Soon Lilian , Braet Filip , Condeelis John 
Published: February 2007

AbstractAlthough genetic and protein manipulations have been the cornerstone for the study and understanding of biological processes for many decades, complimentary nanoscale observations have only more recently been achieved in the live‐imaging mode. It is at the nano measurement level that events such as protein–protein interactions, enzymatic conversions, and single‐molecule stochastic behavior take place. Therefore, nanoscale observations allow us to reinterpret knowledge from large‐scale or bulk techniques and gain new insight into molecular events that has cellular, tissue, and organismal phenotypic manifestations. This review identifies pertinent questions relating to the sensing and directional component of cancer cell chemotaxis and discusses the platforms that provide insight into the molecular events related to cell motility. The study of cell motility at the molecular imaging level often necessitates the use of devices such as microinjection, microfluidics, in vivo/intravital and in vitro chemotaxis assays, as well as fluorescence methods like uncaging and FRET. The micro‐ and nanofabricated devices that facilitate these techniques and their incorporation to specialized microscopes such as the multiphoton, AFM, and TIR‐FM, for high‐resolution imaging comprise the nanoplatforms used to explore the mechanisms of carcinogenesis. In real‐time observations, within a milieu of physiological protein concentrations, true states of dynamic and kinetic fluxes can be monitored. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Spot Counting to Locate Fetal Cells in Maternal Blood and Tissue: A Comparison of Manual and Automated Microscopy
Authors: Johnson Kirby L. , Stroh Helene , Khosrotehrani Kiarash , Bianchi Diana W. 
Published: February 2007

AbstractBackground: Fetal cell detection in maternal tissue requires an accurate, efficient, and reproducible microscopy method. Our objective was to compare manual scoring to a commercially available automated scanning system for the detection of chromosome signals by fluorescence in situ hybridization (FISH). Methods: X and Y chromosome FISH signals were detected on slides of calibrated mixtures of blood, paraffin‐embedded liver sections, and post‐termination blood. For manual scoring (400× magnification), the number of cells located and duration of scoring were recorded. For automated scanning using the Metasystems Metafer3/Metafer4 Scanning System (200× magnification), duration of scanning, number of gallery images generated, duration of manual review of gallery images, and number of confirmed fetal cells were recorded. Results: From all slides the number of target fetal cells located by manual and automated microscopy was highly correlated (r = 0.90). However, automated scanning required on average 4‐fold more time than manual scoring (P < 0.0001), with an average automated scanning time of 9.7 h per slide compared with 2.4 h per slide when scored manually. Conclusions: In general, the accuracy of automated and manual microscopy is comparable, although manual scoring is more efficient because of the level of magnification necessary for automated scanning of cells, and a large number of gallery images generated by automated scanning that must then be reviewed manually. This suggests that when rapid analysis is required (i.e., clinical situations), manual microscopy is preferable. In contrast, automated scanning may have advantages over manual microscopy when time constraints are less imposed (i.e., research situations). Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Histatin‐induced Alterations in Candida albicans: A Microscopic and Submicroscopic Comparison
Authors: Isola Raffaella , Isola Michela , Conti Gabriele , Lantini Maria Serenella , Riva Alessandro 
Published: February 2007

AbstractDespite the numerous studies performed in an attempt to clarify the issue, the mechanism of action of salivary histatins remains unclear. The aim of the present study was to correlate histatin‐induced morphological changes in Candida albicans by fluorescence microscopy (FM), transmission electron microscopy (TEM), and high resolution scanning electron microscopy (HRSEM). Each of the fluorescent dyes used by FM (i.e., tetramethylrhodamine methyl ester perchlorate for mitochondrial potential, Lysotracker for lysosome acidic compartment, and 4′,6‐diamino‐2‐phenylindole dihydrochloride for DNA) exhibited a specific staining in control cells. Following histatin treatment, we observed a recurring staining pattern, corresponding to fluorescence concentration along the cell periphery, suggesting a loss of dye specificity. To assess histatin‐induced cytoplasmic modifications, ultrastructural analysis was then carried out. After treatments with histatins, TEM revealed characteristic intracellular modifications including: vacuole overgrowth, nuclear disappearance, loss of organelle identity, as well as the appearance of electron‐dense membranes, likely of mitochondrial origin. Additionally, structures resembling autophagosomes were occasionally observed. By HRSEM, mitochondrial swelling was invariably the first sign of a histatin‐induced effect. Other modifications included intracellular membrane disarrangement, organelles in disarray, and a large central cavity with deformed bodies displaced to the cell periphery, similar to what was detected by TEM. In summary, our study illustrates the occurrence of ultrastructural modifications following administration of histatins. Observations made with FM, TEM, and HRSEM provided different views of the same signs, demonstrating a definite action of histatins on C. albicans morphology. The possible functional meanings of these morphological results is discussed in light of the most recent biochemical data on histatin fungicidal activity. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Homomorphism bounds for oriented planar graphs
Authors: Marshall T. H. 
Published: February 2007

AbstractIf ${\cal C}$ is a class of oriented graphs (directed graphs without opposite arcs), then an oriented graph is a homomorphism bound for ${\cal C}$ if there is a homomorphism from each graph in ${\cal C}$ to H. We find some necessary conditions for a graph to be a homomorphism bound for the class of oriented planar graphs and prove that such a graph must have maximum degree at least 16; thus there exists an oriented planar graph with oriented chromatic number at least 17. © 2007 Wiley Periodicals, Inc. J Graph Theory 55: 175–190, 2007
Design and development of a prototype endocavitary probe for high‐intensity focused ultrasound delivery with integrated magnetic resonance imaging
Authors: Wharton Iain P. , Rivens Ian H. , ter Haar Gail R. , Gilderdale David J. , Collins David J. , Hand Jeff W. , Abel Paul D. , deSouza Nandita M. 
Published: February 2007

AbstractPurposeTo integrate a high intensity focused ultrasound (HIFU) transducer with an MR receiver coil for endocavitary MR‐guided thermal ablation of localized pelvic lesions.Materials and MethodsA hollow semicylindrical probe (diameter 3.2 cm) with a rectangular upper surface (7.2 cm × 3.2 cm) was designed to house a HIFU transducer and enable acoustic contact with an intraluminal wall. The probe was distally rounded to ease endocavitary insertion and was proximally tapered to a 1.5‐cm diameter cylindrical handle through which the irrigation tubes (for transducer cooling) and electrical connections were passed. MR compatibility of piezoceramic and piezocomposite transducers was assessed using gradient‐echo (GRE) sequences. The radiofrequency (RF) tuning of identical 6.5 cm × 2.5 cm rectangular receiver coils on the upper surface of the probe was adjusted to compensate for the presence of the conductive components of the HIFU transducers. A T1‐weighted (T1‐W) sliding window dual‐echo GRE sequence monitored phase changes in the focal zone of each transducer. High‐intensity (2400 W/cm–2), short duration (<1.5 seconds) exposures produced subtherapeutic temperature rises.ResultsFor T1‐W images, signal‐to‐noise ratio (SNR) improved by 40% as a result of quartering the conductive surface of the piezoceramic transducer. A piezocomposite transducer showed a further 28% improvement. SNRs for an endocavitary coil in the focal plane of the HIFU trans‐ducer (4 cm from its face) were three times greater than from a phased body array coil. Local shimming improved uniformity of phase images. Phase changes were detected at subtherapeutic exposures.ConclusionWe combined a HIFU transducer with an MR receiver coil in an endocavitary probe. SNRs were improved by quartering the conductive surface of the piezoceramic. Further improvement was achieved with a piezocomposite transducer. A phase change was seen on MR images during both subtherapeutic and therapeutic HIFU exposures. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Head and neck imaging: The role of CT and MRI
Authors: Wippold Franz J. 
Published: February 2007

AbstractHigh‐resolution computed tomography (CT) and magnetic resonance imaging (MRI) have become indispensable tools for the evaluation of conditions involving the head and neck. Complex anatomic structures and regions, such as the orbit, skull base, paranasal sinuses, deep spaces of the neck, larynx, and lymph nodes, require that the radiologist be familiar with the imaging modalities available and their appropriate applications. The purpose of this article is to review the techniques of CT and MRI and the roles they play in clinical practice, including head and neck disorders. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Measurement of MR signal and T2* in lung to characterize a tight skin mouse model of emphysema using single‐point imaging
Authors: Olsson Lars E. , Lindahl Maria , Önnervik Per‐Ola , Johansson Lars B. , Palmér Malin , Reimer Martina Kvist , Hultin Leif , Hockings Paul D. 
Published: February 2007

AbstractPurposeTo evaluate whether MRI signal and T2* measurements of lung tissue acquired at ultrashort detection times (tds) can detect emphysematous changes in lungs.Materials and MethodsMR signal intensity of in vivo mouse lungs was measured at 4.7 T at tds of 0.2 and 0.4 msec using single‐point imaging (SPI). T2* was calculated from the measurements obtained at the two tds. Two groups of 8‐ and 30‐week‐old Tight Skin (TS) and aged‐matched CB57BL/6 mice were examined. The TS mice spontaneously developed emphysema‐like alveolar enlargement. In vivo micro‐computed tomography (μCT) scanning and histology were used as reference methods.ResultsMR signal and T2* were significantly lower in the lungs of TS mice than in controls. There were no significant differences between the different age groups. MR signal in lung parenchyma correlated linearly (P < 0.0001, r = 0.89) with μCT mass density, and T2* correlated linearly (P < 0.0001, r = –0.91) with the alveoli size (mean linear intercept [MLI]).ConclusionThe MR signal intensity and T2* measured at short tds can be used as imaging biomarkers to characterize parenchyma density and alveolar size, respectively. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Evaluation of intrarenal oxygenation in mice by BOLD MRI on a 3.0T human whole‐body scanner
Authors: Li Lu‐Ping , Ji Lin , Lindsay Scott , Prasad Pottumarthi V. 
Published: February 2007

AbstractPurposeTo extend observations on intra‐renal oxygenation with blood oxygen level‐dependent (BOLD) MRI in human and rats to mouse kidneys imaged with a human whole‐body scanner.Materials and MethodsRenal BOLD MRI studies were performed on a 3.0T scanner using a multiple gradient‐echo (mGRE) sequence with a custom‐designed 2.0‐cm surface coil to acquire six T2*‐weighted images in mice (N = 8) at an in‐plane resolution of 156 × 156 μm2. BOLD MRI data were obtained before and after administration of furosemide (10 mg/kg intravenously [i.v.]).ResultsThe mean weight of eight mice was 24.6 ± 1.0 g. The baseline renal R2* (mean ± standard error [SE]) was 28.6 ± 2.1 seconds–1 in the renal cortex (CO), 35.4 ± 2.2 in the outer medulla (OM), and 21.2 ± 2.1 seconds–1 in the inner medulla (IM). The BOLD response to furosemide (ΔR2*) was 4.1 ± 1.4 in the CO, 10.1 ± 2.1 seconds–1 in the OM, and 3.4 ± 0.8 seconds–1 in the IM in mice.ConclusionIntrarenal BOLD MR images with sufficiently high resolution can be obtained on a human whole‐body scanner when combined with a small receiver coil to allow studies in mice. Both baseline R2* and ΔR2* values following administration of furosemide were consistent with previous experience in humans and rats. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Differential expression of tissue inhibitor of metalloproteinases‐3 in cultured astrocytes and neurons regulates the activation of matrix metalloproteinase‐2
Authors: Liu Wenlan , Furuichi Takamitsu , Miyake Minoru , Rosenberg Gary A. , Liu Ke Jian 
Published: February 2007

AbstractMatrix metalloproteinases (MMPs) degrade the extracellular matrix and are implicated in the pathogenesis of several neurological diseases. Secreted in proforms, the MMPs require activation. Tissue inhibitors of matrix metalloproteinases (TIMPs) regulate the activity of MMPs. We investigated the expression of MMP‐2 and ‐9, and the role of the TIMP‐3 in MMP‐2 activation, using cultures of cortical neurons and astrocytes. Under basal conditions, astrocytes and neurons produced low levels of pro‐MMP‐2, and ‐9. Stimulation with lipopolysaccharide (LPS) markedly increased pro‐MMP‐9 production in astrocytes, with only a slight increase in neurons. Pro‐MMP‐2 were constitutively expressed in both cell types, but with a much higher level in the astrocytes. Real‐time RT‐PCR showed that the mRNA levels of MMP‐2 and ‐9 paralleled their gelatinolytic activities in the gelatin zymograms. Interestingly, active MMP‐2 was observed only in neuronal cultures. TIMP‐2 and TIMP‐3 are constitutively expressed in astrocytes and neurons. However, astrocytes expressed much higher levels of TIMP‐3 mRNA and protein than neurons. Knockdown of TIMP‐3 with small interfering RNA (siRNA) significantly increased MMP‐2 activation in astrocytes. These results indicate that astrocytes are a more important intrinsic cellular source of MMP‐2 and ‐9 than neurons under normal and neuroinflammatory conditions. TIMP‐3 may be the key factor determining the differential activation of MMP‐2 in astrocytes and neurons. © 2007 Wiley‐Liss, Inc.
Lack of hippocalcin causes impairment in Ras/extracellular signal‐regulated kinase cascade via a Raf‐mediated activation process
Authors: Noguchi Hajime , Kobayashi Masaaki , Miwa Naofumi , Takamatsu Ken 
Published: February 2007

AbstractHippocalcin (Hpca) is a member of the neuronal calcium sensor protein family and is highly expressed in hippocampal neurons. Hpca‐deficient (Hpca–/–) mice display a defect in cAMP response element‐binding protein (CREB) activation associated with impaired spatial and associative memory. Here we examine the involvement of Hpca in the extracellular signal‐regulated kinase (ERK) cascade leading to CREB activation, because application of PD98059, a broad ERK cascade inhibitor, has resulted in similar levels of CREB activation in Hpca–/– hippocampus. N‐methyl‐D‐aspartate (NMDA)‐ and KCl‐induced phosphorylation of ERK was significantly attenuated in Hpca–/– hippocampal slices, as was ionomycin‐induced phosphorylation of ERK, whereas forskolin and 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) stimulation yielded indistinguishable levels of ERK phosphorylation in both wild‐type and Hpca–/– slices. In an in vitro reconstitution assay system, recombinant Hpca affected neither Raf‐1 protein kinase activity with recombinant MEK‐1 as a substrate nor MEK‐1 kinase activity with ERK2 as a substrate. Activation of Ras by NMDA and KCl stimulation of hippocampal slices showed no obvious changes between the two genotypes; however, phosphorylation of Raf‐1 was significantly lower in Hpca–/– slices. These results suggest that Hpca plays an important role in the activation of Raf conducted by Ras. © 2007 Wiley‐Liss, Inc.
Intermediate chain subunit as a probe for cytoplasmic dynein function: Biochemical analyses and live cell imaging in PC12 cells
Authors: Myers Kenneth R. , Lo Kevin W.‐H. , Lye R. John , Kogoy John M. , Soura Violetta , Hafezparast Majid , Pfister K. Kevin 
Published: February 2007

AbstractCytoplasmic dynein 1 is a multi‐subunit motor protein responsible for microtubule minus end‐directed transport in axons. The cytoplasmic dynein intermediate chain subunit has a scaffold‐like role in the dynein complex; it directly binds to four of the other five subunits, the heavy chain and the three light chains. The intermediate chain also binds the p150 subunit of dynactin, a protein that is essential for many dynein functions. We reexamined the generation of rat cytoplasmic dynein intermediate chain isoforms by the alternative splicing of the two genes that encode this subunit and identified an additional splicing site in intermediate chain gene 1. We reinvestigated the expression of the intermediate chain 1 isoforms in cultured cells and tissues. The Loa mouse, which is homozygote lethal, contains a missense mutation in the region of the cytoplasmic dynein heavy chain gene that binds the intermediate chain. Protein binding studies showed that all six intermediate chains were able to bind to the mutated heavy chain. GFP‐tagged intermediate chains were constructed and PC12 cell lines with stable expression of the fusion proteins were established. Live cell imaging and comparative immunocytochemical analyses show that dynein is enriched in the actin rich region of growth cones. © 2007 Wiley‐Liss, Inc.
The influence of temperature on the relations between thermal death, growth and yield in Candida utilis
Authors: Madeira‐Lopes A. 
Published: February 2007

AbstractIn the yeast Candida utilis an associative temperature profile was found with respect to thermal death and growth. The cardinal temperatures were the following: optimum temperature for growth, 36°C, minimum temperature of thermal death, 37.9°C; final maximum temperature for growth, 40.1°C; initial maximum temperature for growth, 40.7°C. The growth yield on glucose only decreased near the final maximum temperature for growth.
Abbau von Mischsubstraten durch Hefen III. Wachstumsparameter
Authors: Bachmann Beate , Siegel J. , Krauel H. H. , Weide H. 
Published: February 2007

AbstractThe growth characteristics of two Candida strains W1, W2, have been examined on the single substrates d‐glucose, d‐galactose, d‐xylose, d‐arabinose in batch culture. The importance of growth parameters μmax, KS and Y with regard to possible functions of single strains in mixed populations during degradation of mixed substrates has been discussed.
The effect of growth substrate on the levels of citric acid cycle enzymes in the facultative methylotroph Arthrobacter 2B2
Authors: Paddon C. J. , Payton M. A. , Hartley B. S. 
Published: February 2007

AbstractAll enzymes of the citric acid cycle were found to be present in cell‐free extracts of the facultative methylotroph Arthrobacter 2B2 except 2‐oxoglutarate dehydrogenase and pyruvate dehydrogenase. The dehydrogenase (E1) and lipoamide dehydrogenase (E2) component of 2‐oxoglutarate could be detected indicating that the complex was present, but may be very labile. No great differences in enzyme levels were detected between cells grown on trimethylamine and those on multicarbon substrates. Citrate synthase was found to be insensitive to inhibition by NADH or 2‐oxoglutarate, but some inhibition was observed with ATP.
Auswirkungen von Mutanteninduktion und Protoplastenfusion auf ausgewählte Dehydrogenase‐Muster von Pichia guilliermondii
Authors: Büttner Martina , Birnbaum D. , Böttcher F. 
Published: February 2007

AbstractWe investigated the enzyme patterns of two wild‐type strains, two auxotrophic mutants and some fusion hybrids of Pichia guilliermondii after the electrophoretic separation of their crude cell extracts in dependence on the cultivation on mineral salt medium with different carbon sources. The wild‐type strains showed a constitutive synthesis of one NAD‐specific and some NADP‐specific enzymes and their ability to oxidize primary alcohols with a chain length from C2 to C8. After the induction of mutants auxotroph for amino acids, nicotinic acid or adenine we found different enzyme patterns, too. Prototrophic fusion hybrids obtained via protoplast fusion of the two double auxotrophic mutants showed behaviour either characteristic for the wild‐type strains or characteristics of their parental strains and in some cases also combination of parental enzyme patterns. The behaviour of the hybrids seems to be dependent on the quantity of DNA transferred into each fusion hybrid from the parental mutant strains.So the method of protoplast fusion allows to get qualitatively different hybrids.
A radioimmunoassay for (p)ppGpp and its application to Streptomyces hygroscopicus
Authors: Riesenberg D. 
Published: February 2007

AbstractAradioimmunoassay for (p)ppGpp was set up and applied to Streptomyces hygroscopicus. The (p)ppGpp specific antibodies obtained from rabbits immunized with ppGpp‐human serum albumin could not distinguish between guanosine‐5′‐triphosphate‐3′‐diphosphate (pppGpp) and guanosine‐5′‐diphosphate‐3′‐diphosphate (ppGpp) whereas the cross reacitivity against structurally related nucleotides was negligible. Therefore, the antibodies were used for determination of (p)ppGpp, i. e. the sum of pppGpp and ppGpp. The pretreatment of biological samples for quantification of (p)ppGpp included formic acid extraction of cell pool followed by step gradient elution on DEAE‐Sephadex A25 (Cl−) column for separation of (p)ppGpp from nucleotides with three or less phosphate groups. The very sensitive radioimmunoassay allowed determination of very low amounts: 1–50 pmoles (p)ppGpp per assay tube. The application of the RIA to S. hygroscopicus revealed a basal level in exponentially growing mycelium of about 2 pmoles (p)ppGpp per mg dry weight. The equilibrated pool size after induction of stringent response with serine hydroxamate was found to be about 30 pmoles (p)ppGpp per mg dry weight.
A stable L‐form variant of a Rhodococcus strain (B 245)
Authors: Das T. K. , Banerjee A. K. 
Published: February 2007

AbstractA stable L‐form variant was isolated from a soil‐inhabiting, orange red‐pigment coryneform bacterium belonging to the genus Rhodococcus. The variant differed from the parental strain in colony and cell morphology, in growth rate and obligatory requirement of B‐vitamins and amino acids, in temperature sensitivity, in susceptibility to antibiotics affecting cell wall synthesis, and in the inability to utilize hydrocarbons as sole carbon sources for growth.
Localization of a streptothricin acetyl transferase in cells of Escherichia coli K‐12
Authors: Seltmann G. , Wolter E.‐J. 
Published: February 2007

AbstractStreptothricin acetyl transferase coded for by plasmids pIE636 and pIE637 in Escherichia coli K‐12 was found to be located at the inner side of the cytoplasmic membrane.
Morphological characterization of the Serratia marcescens bacteriophage SLP
Authors: Viñas M. C. , Gargallo D. , Lorén J. G. , Guinea J. 
Published: February 2007

AbstractSLP is a lambda‐like bacteriophage specific for Serratia marcescens. strains. Morphological studies have demonstrated that SLP virions present two cross‐bar structures on its tail not described in bacteriophages specific for Enterobacteriaceae. SDS‐polyacrylamide gel electrophoresis of major capsid proteins as well as electron micrographs are reported.