bluuebunny/crossref_metadata_2025 huggingface dataset:
Fascins, a family of actin bundling proteins
Authors: Edwards Robert A. , Bryan Joseph
Published: February 2005

Fascin is an actin‐bundling protein that was first isolated from cytoplasmic extracts of sea urchin eggs [Kane, 1975: J. Cell Biol. 66:305–315] and was the first bundling protein to be charactrized in vitro. Subsequent work has shown that fascin bundles actin filaments in fertilized egg microvilli and filopodia of phagocytic coelomocytes [Otto et al., 1980: Cell Motil. 1:31–40; Otto and Bryan, 1981: Cell Motil. 1:179–192]. Fifteen years later, the molecular cloning of sea urchin fascin [Bryan et al., 1993: Proc. Natl. Acad. Sci. U.S.A. 90:9115–9119] has led to the identification and characterization of homologous proteins in Drosophila [Cant et al., 1994: J. Cell Biol. 125:369–380], Xenopus [Holthuis et al., 1994: Biochim. Biophys. Acta. 1219:184–188], rodents [Edwards et al., 1995: J. Biol. Chem. 270:10764–10770], and humans [Duh et al., 1994: DNA Cell Biol. 13:821–827; Mosialos et al., 1994: J. Virol. 68:7320–7328] that bundle actin filaments into structures which stabilize cellular processes ranging from mechanosensory bristles to the filopodia of nerve growth cones. Fascin has emerged from relative obscurity as an exotic invertebrate egg protein to being recognized as a widely expressed protein found in a broad spectrum of tissues and organisms. This purpose of this review is to relate the early studies done on sea urchin and HeLa cell fascins to the recent molecular biology that defines a family of bundling proteins, and discuss the current state of knowledge regarding fascin structure and function. © 1995 Wiley‐Liss, Inc.
Centrin in the photoreceptor cells of mammalian retinae
Authors: Wolfrum Uwe
Published: February 2005

Photoreceptor cells of vertebrate retinae are highly specialized ciliary cells. Their non‐motile ciliated structure is restricted to the so‐called connecting cilium at the joint between the light sensitive outer segment and the metabolically active inner segment. Extensive bidirectional intracellular transport between both segments is forced to occur through this tight connecting cilium. In the present study it is shown that the Ca2+‐binding, phospho‐protein centrin is present in mammalian retinae. Western blot and immunoprecipitation experiments reveal that anti‐centrin antibodies react with purified photoreceptor cell fractions of retinae in bands at a molecular weight of 20 kDa, the molecular weight of centrins found in other cells. Indirect immunofluorescence analysis of cryosections through retinae of different mammalian species show that centrin is present only in centrosomes and basal bodies but also more extensively at the linkage between the inner and the outer segment of the photoreceptor cells. Immunocytological studies on isolated rod cells and immunoelectron microscopy clearly demonstrate a unique presence of centrin in the connecting cilium of photoreceptor cells. High molecular identity between centrins in lower eukaryotes and mammals indicates that centrin may play a role in cellular motility and/or in microtubule severing in the mammalian retina. © 1995 Wiley‐Liss, Inc.
Dynein family of motor proteins: Present status and future questions
Authors: Gibbons I. R.
Published: February 2005

Analysis of sequence relationships in dynein heavy chains shows that dynein motor proteins comprise a single homologous family with three main branches, cytoplasmic dynein, axonemal dynein, and a third branch represented by DYH1B that lies between the other two. In all branches of the family the dynein heavy chain has four copies of the P‐loop motif for a nucleotide‐binding site spaced ∼300 residues apart in its midregion, with the amino acid sequence GPAGTGKT in the P‐loop of the hydrolytic ATP‐binding site. Cytoplasmic dyneins appear more primitive in that the heavy chain usually occurs as a homodimer, with traces of the early evolution of its four P‐loop motifs by gene duplication being recognizable. In the axonemal subfamily the heavy chains occur as heterodimers or heterotrimers encoded by multiple genes, and their non‐hydrolytic P‐loop motifs are much more divergent with little trace of their origin by gene duplication. The DYH1B subfamily is more closely related to the cytoplasmic dyneins in sequence, but appears related to axonemal dyneins in function since it becomes upregulated during reciliation and has not been found in organisms, such as yeast and Dictyostelium, that are totally without cilia or flagella.
Computer simulation of nerve growth cone filopodial dynamics for visualization and analysis
Authors: Buettner Helen M.
Published: February 2005

The neuronal growth cone plays a fundamental role in nerve development and regeneration. A sensory‐motile structure, it determines the path of axonal extension through its interactions with the extracellular environment, ultimately directing the formation of functional connections in the nervous system. Though several mechanisms of interaction have been proposed, these have been difficult to describe quantitatively due to the complexity of growth cone behavior, as manifested in the randomly and rapidly changing shape of the growth cone. The application of mathematical techniques to model growth cone shape and motility in terms of underlying processes represents a promising approach with untapped potential for helping to unravel this complexity while revealing new insights into axonal pathfinding events. This paper presents a simulation model for filopodial dynamics, a primary feature of the motile growth cone. The model produces realizations of dynamic filopodial structure on representative growth cones for a given set of model parameters, which include the rates of filopodial initiation, extension, and retraction, filopodial length at maximum extension, and angular orientation. These parameters are based on recent experimental characterization of filopodial dynamics [Buettner et al., 1994: Dev. Biol. 163:407–422]. The mathematical relationship between the model parameters and average filopodial number and length per growth cone is described, and the contribution of individual parameters to overall filopodial morphology is illustrated both visually and numerically. In addition, the model is used to simulate filopodial encounter with a target for various conditions of filopodial dynamics. The result is characterized in terms of a mean encounter time for a population of growth cones and provides an indication of the effect of individual parameters of filopodial dynamics on the encounter process. Future experimental testing will be required to develop the model further. However, in its current form, the model enables a first approximation analysis of many hypotheses of growth cone migration and pathfinding and offers insight into the the underlying mechanismes of nerve growth and regeneration. © 1995 Wiley‐Liss, Inc.
Plakoglobin: Kinetics of synthesis, phosphorylation, stability, and interactions with desmoglein and E‐cadherin
Authors: Pasdar Manijeh , Li Zhi , Chlumecky Vera
Published: February 2005

We have analyzed the kinetics of synthesis, phosphorylation, and stability of the soluble and insoluble plakoglobin (PG) and their interactions with Dsg1 and E‐cadherin in Madin‐Darby canine kidney (MDCK) epithelial cells in the absence of cell adhesion and after the induction of cell‐cell contact. Using a combination of biochemical and morphological approaches, we show that newly synthesized PG enters a soluble:insoluble pool of proteins in a 60:40 ratio regardles of cell‐cell contact. Following synthesis, PG is increasingly found in the insoluble pool. Although cell‐cell contact does not effect either the size of each pool or the rate or efficiency of the transfer from the soluble into the insoluble pool, it results in a significant increase in the metabolic stability of the newly synthesized insoluble PG. The soluble PG initially forms separate complexes with E‐cadherin and Dsg1. PG‐Dsg1 complexes become insoluble and localize to the desmosome. PG‐E‐cadherin complexes remain soluble and are distributed intracellularly. The insoluble PG and E‐cadherin detected at the cell periphery remain distinctly separate, as demonstrated previously [Hinck et al., 1994:J. Cell Biol.125:1327–1340; Nathke et al., 1994:J. Cell Biol.125:1341–1352]. In addition, we detected a separate pool of PG which is not associated with either Dsg1 or E‐cadherin and after the induction of cell‐cell contact becomes primarily insoluble and is distributed along the lateral membrane. Phoshorylation analysis showed that there is a significantly greater amount of phosphorylated PG in the soluble pool than in the insoluble pool. In addition the soluble pool is both serine and theronine phosphorylated, whereas the insoluble PG is primarily phosphorylated on serine residues. © 1995 Wiley‐Liss, Inc.
Melting behavior and growth of colquiriite laser crystals
Authors: Klimm D. , Uecker R. , Reiche P.
Published: February 2005

Colquiriite‐type crystals like LiCaAlF6, LiSrAlF6, LiCaGaF6, and LiSrGaF6 are interesting host crystals for Cr3+ or Ce3+ laser ion doping. Although the Ca compounds show interesting optical properties, the growth of these crystals is difficult due to incongruent melting. LiCaGaF6 crystallizes with CaF2 deficiency and melts incongruently at 710–720 °C. Hydrolysis with traces of moisture is critical for all fluorides. AlF3 and GaF3 have the highest sensitivity among the main components of the colquiriites. Hydrolysis can only be slightly suppressed by hydrogen fluoride. Elementary fluorine or reactive gases as carbon tetrafluoride are more effective by several orders of magnitude. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray photoelectron spectroscopy investigations of Y3Al5O12:Yb single crystal
Authors: Kruczek M. , Talik E. , Sakowska H. , Gała M. , Świrkowicz M.
Published: February 2005

X‐ray photoelectron spectroscopy was used to study the chemical composition and electronic structure of the Y3Al5O12:Yb (YAG:Yb) crystals. The contamination of the crystal with carbon and oxygen in the broken under UHV sample was found. The dopant concentration of Yb, in the mixed valence state, was determined as 12 %. The aluminium concentration is lower than a nominal value. The chemical shift analysis shows more ionic bond of Y‐O than Al‐O. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman and Rayleigh scattering study of crystalline polyoxyethyleneglycols
Authors: Kozielski M. , Mühle M. , Błaszczak Z. , Szybowicz M.
Published: February 2005

Results of the study of Raman and Rayleigh scattering in crystalline polyoxyethyleneglycols (PEG) and PEG 1500 aqueous solution are reported. The conformational changes of the polymer chain have been studied as a function of PEG water solution concentration and molecular weight. Intensity ratios of the gauche and trans conformation around C–C and C–O bonds have been estimated from the Raman spectra. Moreover, from the Raman band parameters the values of the order parameters versus aqueous solution concentration have been determined. The influence of an external electric field on these parameters has been analysed. Mutual orientation of polyoxyethyleneglycol chains in the crystalline and liquid state has been studied on the basis of the angular correlation parameters obtained from the Rayleigh band intensity as a function of aqueous solution concentration and molecular weight. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical studies of defects generated in neutron‐irradiated Cz‐Si during HP‐HT treatment
Authors: Surma B. , Misiuk A. , Wnuk A. , Londos C. A. , Bukowski A.
Published: February 2005

Neutron‐irradiated Czochralski grown silicon subjected to heat treatment (HT) at 350 °C and 1000 °C under enhanced hydrostatic pressure (HP) was studied in this work. It has been shown that external hydrostatic pressure enhances the creation of VO2 defects in neutron irradiated silicon subjected to the HP ‐ HT treatment at 350 °C. Enhanced formation of platelet‐like oxygen precipitates was found in the samples treated at 1000 °C under 1.1 GPa. This effect was more pronounced in the samples with VO2 defects. Presented results seem to suggest that probably HP helps to transform VO2 to some kind of defects or change alone VO2 defects in the form that can act as an additional nucleus for an additional oxygen precipitation at 1000°C. No correlation between the plate‐like oxygen precipitates related absorption at 1225 cm‐1 and dislocation‐related emission has been confirmed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of InP layers prepared with the addition of Ce, Tm and Lu in the growth melt
Authors: Zavadil J. , Prochazkova O. , Gladkov P. S.
Published: February 2005

InP single crystals were grown by liquid phase epitaxy on semi‐insulating InP:Fe and n‐type InP:Sn substrates with cerium, thulium and lutetium additions to the growth melt. Grown layers were examined by low‐temperature photoluminescence spectroscopy and C‐V measurements. Layers prepared with the addition of Ce and Tm exhibit the change of electrical conductivity from n to p, while those grown with Lu admixture remain n‐type. Ce has been found to be incorporated into the InP lattice and sharp luminescence arising from 2F7/2 → 2F5/2 inner shell transitions of Ce3+ at 3600 nm was detected. The highest purifying effect due to RE addition has been found for Tm admixture, where the impurity concentration was decreased by three orders of magnitude and fine spectral features were revealed by photoluminescence spectroscopy. The addition of Tm into the growth melt enables to prepare thick and pure InP layers of p‐type conductivity – a material promising in the context of semiconductor radiation detectors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinetic Study of Ni2+ and Co2+ Complexation by PADA in AOT‐Based Water‐in‐Oil Microemulsions
Authors: Fernández Esperanza , García‐Río Luis , Knörl Astrid , Leis José Ramón
Published: February 2005

A kinetic study was carried out into the complexation of Ni2+ and Co2+ with the bidentate ligand pyridine‐2‐azo‐p′‐(N,N‐dimethylaniline) (PADA) in AOT/isooctane/water microemulsions [where AOT = sodium bis(2‐ethylhexyl)sulfosuccinate]. The results obtained show that the macroscopic rate constants for the formation of the Ni2+‐PADA and Co2+‐PADA complexes decrease as the surfactant concentration and the water content of the system increase. The rate constants are in all cases greater than those observed in an aqueous medium, with catalytic effects of up to 25 times. To interpret the kinetic results a model has been proposed which considers the distribution of PADA between the continuous medium and the interface of the microemulsion, and the distribution of the Nitest 2+ test2+ and the Co2+ cations between the aqueous microdroplet and the interface. The formation and dissociation reactions of the complexes take place only at the interface. On the basis of the model we obtained values for the rate constants for the formation, ki1, and decomposition, ki–1, of the complexes for various values of W (W = [H2O]/[AOT]). The results show that ki–1 is independent of the composition of the microemulsion and that ki1 increases as W decreases. The results also show that the rate constants for the formation of the Co2+‐PADA complex are approximately 50 times greater than those of the Ni2+‐PADA complex. These results are compatible with the fact that the reaction follows an Eigen–Wilkins‐type mechanism and that, in the presence of added salt, there is an increase in the rate constant of water exchange as the saline content of the microdroplet increases, that is, as W decreases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Direct Halogenation of Alcohols and Their Derivatives with tert‐Butyl Halides in the Ionic Liquid [pmIm]Br under Sonication Conditions – A Novel, Efficient and Green Methodology
Authors: Ranu Brindaban C. , Jana Ranjan
Published: February 2005

A novel halogenating reagent system for direct halogenation of alcohols has been developed. tert‐Butyl bromide, chloride and iodide in combination with the ionic liquid [pmIm]Br have been found to convert alcohols into the corresponding bromides, chlorides and iodides under sonication conditions (or heating) in good yields. Although a variety of primary and secondary alcohols participated in this reaction without any difficulty, tertiary alcohols remained inert. Several alcohol derivatives such as OTMS, OTBDMS, OAc, OTS and OTHP are also transformed into the corresponding halides in one‐pot fashion by this procedure. A plausible rationale for this transformation is also presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Total Synthesis of 3‐Hydroxydrimanes Mediated by Titanocene(III) – Evaluation of Their Antifeedant Activity
Authors: Justicia José , Oltra J. Enrique , Barrero Alejandro F. , Guadaño Ana , González‐Coloma Azucena , Cuerva Juan M.
Published: February 2005

We describe the first synthesis of 3β‐hydroxydihydroconfertifolin (3) and 3β‐hydroxycinnamolide (4), together with improved procedures for the preparation of other 3‐hydroxydrimanes (2 and 5) scarce in nature. The key step was the titanocene(III)‐promoted cyclization of epoxypolyprenes, readily prepared from commercial polyenes. In this way, we confirm the viability of our procedure for the synthesis of drimane sesquiterpenoids with different functionalization patterns. We also report on the antifeedant activity of 2–5 against four insect species with different feeding ecologies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Asymmetric Synthesis of Isoquinoline Derivatives from Amino Acids
Authors: Sieck Oxana , Ehwald Max , Liebscher Jürgen
Published: February 2005

Reaction of isoquinolines 1 with N‐arylsulfonylamino acid fluorides 2 provides a highly stereoselective access to new dihydroimidazo[2,1‐a]isoquinolin‐3‐ones 5 via intermediate N‐acylisoquinolinium salts 3. Addition reactions to the en‐amine double bond, such as hydrogenation or epoxidation with dimethyldioxirane, leads to tetrahydroimidazo[2,1‐a]isoquinoline‐3‐ones 6, 7 and oxiranes 8, respectively. Opening of the oxirane ring of the 8 with nucleophiles allows the synthesis of hydroxytetrahydroimidazo[2,1‐a]isoquinolin‐3‐ones 10 or 12 or of the polycyclic 1,4‐dioxane 13 in high stereoselectivity. The regioselectivity of the oxiran ring opening depends on the kind of nucleophile and the conditions. Reaction of dihydroisoquinoline with O‐TBDMS‐mandelic acid chloride 15 leads to a tetrahydrooxazolo[2,3‐a]isoquinoline 17 with opposite facial selectivity as compared with dihydroimidazo[2,1‐a]isoquinolin‐3‐ones 5. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Be(II) Graphite Coated Membrane Sensor Based on a Recently Synthesized Benzo‐9‐Crown‐3 Derivative
Authors: Ganjali Mohammad Reza , Akbar Vahideh , Norouzi Parviz , Moghimi Abolghasem , Sepehrifard Ali
Published: February 2005

A highly sensitive and selective membrane electrode with 9‐crown‐3 derivative (CD) as ionophore, potassium tetrakis‐(p‐chlorophenyl) borate as anionic additive (KTB), acetophenone (AP) as solvent mediator was prepared and investigated as a Be(II) sensor. The best performance was observed with the membrane having the percent ratio 30% PVC: 8% CD: 6% KTB: 56% Acetophenone. The poly(vinyl chloride) PVC membrane containing 9‐crown‐3 derivative (CD) directly coated on a graphite electrode, shows a Nernstian response for Be(II) ions over a very wide concentration range (1.0×10−1−1.0×10−7 M) with a detection limit of 8.0×10−8 M (ca. 0.72 ng/mL). It has a fast response time of ca. 20 s and can be used for at least 10 weeks without any major deviation in potential. The proposed sensor exhibits very good selectivity with respect to common alkali, alkaline earth, transition and heavy metal ions. The proposed sensor was used as end point indicator electrode in the titration of Be(II) ions with EDTA. It was also applied to determination of Be(II) in real sample.
An Electrochemical Biosensor with Cholesterol Oxidase/ Sol‐Gel Film on a Nanoplatinum/Carbon Nanotube Electrode
Authors: Qiaocui Shi , Tuzhi Peng , Yunu Zhu , Yang Catherine F.
Published: February 2005

The carbon nanotubes decorated nanoplatinum (CNT‐Pt) were prepared using a chemical reduction method and a novel base electrode was constructed by intercalating CNT‐Pt on the surface of a waxed graphite electrode. The results showed that the nano‐particles of platinum at a waxed graphite electrode exhibits high catalytic activity for the reduction of hydrogen peroxide. The cholesterol oxidase (ChOx), chosen as a model enzyme, was immobilized with sol‐gel on the CNT‐Pt base electrode to construct a biosensor. The current response of the biosensor for cholesterol was very rapid (<20 s). The linear range for cholesterol measurement was 4.0×10−6 mol/L −1.0×10−4 mol/L with a detection limit of 1.4×10−6 mol/L. The experiments also showed that the ChOx/sol‐gel/CNT‐Pt biosensor was sensitive and stable in detecting cholesterol in serum samples.
Stripping Voltammetry with Bismuth Modified Graphite‐Epoxy Composite Electrodes
Authors: Kırgöz Ülkü Anık , Marín Sergi , Pumera Martin , Merkoçi Arben , Alegret Salvador
Published: February 2005

The attractive performance of graphite‐epoxy composite electrodes (GECE) surface‐modified with a bismuth film (Bi‐GECE) for simultaneous and separate stripping determination of trace amounts of heavy metals (lead, cadmium and zinc) is described. Several key parameters have been optimized. Bi‐GECEi electrode shows superior accumulation properties when compared to bare GECE or even to Hg‐GECE. Bi‐GECE exhibits well‐defined, undistorted, reproducible and sharp stripping signals with RSD of 2.99%, 1.56% and 2.19% for lead, cadmium and zinc respectively. Detection limits of 23.1, 2.2 and 600 μg/L for lead, cadmium and zinc were obtained. Sharp peaks with high resolution (of neighboring signals) that permit convenient multi‐elemental measurements resulted. The applicability of the electrodes to the real samples (tap water and soil sample) was also tested and promising results with good recoveries were obtained.
Silicon Micromachined Infrared Thin‐Layer Cell for In Situ Spectroelectrochemical Analysis of Aqueous and Nonaqueous Solvent System
Authors: Yun Kwang‐Seok , Joo Segyeong , Kim Hong‐Jeong , Kwak Juhyoun , Yoon Euisik
Published: February 2005

This article reports in situ FTIR monitoring of electrochemical reactions using a silicon‐based thin‐layer cell realized by micromachining fabrication technologies. The proposed device contains a silicon micromachined cavity cell integrated with a gold working electrode, a counter electrode, and a Ag/AgCl reference electrode. Electrochemical, spectroscopic, and spectroelectrochemical characteristics of the fabricated cell have been experimentally measured and exhibited a comparable performance to commercialized CaF2 thin‐layer cells. In situ spectroelectrochemical characteristics have been successfully tested for both 2 mM K3Fe(CN)6 in an aqueous solution and 2 mM ferrocene in a dichloromethane solution using the fabricated thin‐layer cell.
Direct Simultaneous Determination of Cu, Ni and V in Seawater Using Adsorptive Cathodic Stripping Voltammetry with Mixed Ligands
Authors: Cobelo‐García A. , Santos‐Echeandía J. , Prego R. , Nieto O.
Published: February 2005

An analytical procedure is proposed for the direct simultaneous determination in a single scan of Cu, Ni and V in seawater by means of adsorptive cathodic stripping voltammetry (ACSV) with mixed ligands (DMG and catechol). Optimum conditions for the determination of these three elements were studied. Detection limits of the technique depended upon the reproducibility of the procedura blank, and were found to be 0.5 nM for Cu, 0.4 nM for Ni and 0.3 nM for V. The method is suitable for the analysis of estuarine, coastal and open‐ocean waters, and especially to study the metal contamination in areas subject to oil spill events.
Electrochemical Reduction of Pyridinic Herbicides Picloram and Clopyralid on a Mercury Pool Electrode
Authors: Rodríguez Mellado J. M. , Corredor M. C. , Pospíšil L. , Hromadová M.
Published: February 2005

This paper presents the identification by GC/MS of the products obtained after the total reduction of picloram and clopyralid on a mercury pool electrode. The products found in the strongly acidic media reduction of picloram are 4‐amino‐3,5,6‐trichloro‐2‐pyridinecarboxaldehyde, 4‐amino‐3,5,6‐trichloro‐2‐pyridinecarbinol and 4‐amino‐3,5‐dichloro‐2‐pyridinecarboxylic acid; at pH 3–4 the first compound is substituted by 4‐amino‐3,5‐dichloro‐2‐pyridinecarboxaldehyde. For clopyralid 3,6‐dichloro‐2‐pyridinecarbinol was detected. Under the light of such products the overall reduction processes are discussed showing the partial reductive cleavage of chlorine atoms in both cases.
EWSR1 is fused to POU5F1 in a bone tumor with translocation t(6;22)(p21;q12)
Authors: Yamaguchi Shuichi , Yamazaki Yukari , Ishikawa Yuichi , Kawaguchi Noriyoshi , Mukai Hiroyuki , Nakamura Takuro
Published: February 2005

POU5F1(OCT3/4) is a sequence‐specific transcription factor that is essential for keeping germ cells and embryonic stem cells in an immature and pluripotent status. In this article, we report that POU5F1 was fused to EWSR1 in a case of undifferentiated sarcoma derived from pelvic bone with chromosomal translocation t(6;22)(p21;q12). The EWSR1–POU5F1 chimera consists of exons 1–6 of EWSR1 and exons 2–5 and a part of exon 1 of POU5F1. The predicted amino acid sequence indicates that the chimera is composed of the N‐terminal QSY domain of EWS that functions as a transcriptional activation domain and the C‐terminal POU DNA‐binding domains derived from POU5F1. The t(6;22) tumor does not belong to any known categories of bone and soft‐tissue tumors (BSTs). It is suggested that EWS–POU5F1 may act as an oncogenic transcription factor and that its expression may contribute to undifferentiated and immature phenotypes of BST. © 2005 Wiley‐Liss, Inc.
Reduced risk of prostate cancer in men who are childless as compared to those who have fathered a child: A population based case‐control study
Authors: Giwercman Aleksander , Richiardi Lorenzo , Kaijser Magnus , Ekbom Anders , Akre Olof
Published: February 2005

Androgens are believed to play a major role in the etiology of prostate cancer, but studies of sex‐hormone exposure in relation to risk for prostate cancer have been inconclusive. Male fertility may be an indicator of long‐term androgen status. To study the role of testicular function in prostate cancer development, we have assessed number of biological children in relation to risk for this malignancy. We carried out a population‐based case‐control study with retrospective ascertainment of cases occurring in Sweden between 1958–98. In total, 48,850 cases of prostate cancer were identified through the nation‐wide Cancer Registry. For each case, one control, matched by year of birth, was randomly selected from the Swedish population. Information on offspring was obtained from the Swedish Multi‐Generation Registry. We estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between number of offspring and risk for subsequent prostate cancer. Being childless or having fathered one child only were associated with reduced risks for prostate cancer compared to having fathered 2 or more children (OR = 0.83; 95% CI = 0.81–0.86 and OR = 0.93; 95% CI = 0.90–0.96, respectively). There was no further change in risk associated with fathering of more than 2 children. The risk for prostate cancer is reduced among childless men. A dysfunctioning reproductive apparatus fueling to a lesser extent prostatic growth, could be a plausible mechanism of this association. © 2005 Wiley‐Liss, Inc.
Pilot screening programme for small molecule activators of p53
Authors: Berkson Rachel G. , Hollick Jonathan J. , Westwood Nicholas J. , Woods Julie A. , Lane David P. , Lain Sonia
Published: February 2005

Activation of the p53 tumour suppressor is predicted to have therapeutically beneficial effects. Many current anti‐cancer therapies activate the p53 response via DNA damage. Non‐genotoxic activation of the p53 pathway would open the way to long‐term and possibly prophylactic treatments. We have established a simple protocol to screen small compound libraries for activators of p53‐dependent transcription, and to select and characterise the most interesting hits, which include non‐genotoxic activators. These compounds or their derivatives are of potential clinical interest. This approach may also lead to the identification of novel p53‐activating compound families and possibly to the description of novel molecular pathways regulating p53 activity. © 2005 Wiley‐Liss, Inc.
Ly6 family member C4.4A binds laminins 1 and 5, associates with galectin‐3 and supports cell migration
Authors: Paret Claudia , Bourouba Mehdi , Beer Alexander , Miyazaki Kaoru , Schnölzer Martina , Fiedler Sabine , Zöller Margot
Published: February 2005

C4.4A is a member of the Ly6 family, with low homology to uPAR. It has been detected mainly on metastasizing carcinoma cells and proposed to be involved in wound healing. So far, C4.4A has been observed as an orphan receptor, and its functional activity has not been explored. Using recombinant rat C4.4A (rrC4.4A) made in a eukaryotic expression system, we demonstrate by immunohistology that C4.4A ligands are strongly expressed in tissues adjacent to squamous epithelia of, e.g., tongue and esophagus, the expression pattern partly overlapping with laminin (LN) and complementing the C4.4A expression that is found predominantly on the basal layers of squamous epithelium. ELISA screening of several components of the extracellular matrix revealed selective binding of rrC4.4A to LN1 and LN5 and that transfection of the BSp73AS tumor line with C4.4A cDNA (BSp73AS‐1B1) promoted LN1 and LN5 binding. Binding of BSp73AS‐1B1 to LN5 and, less markedly, LN1 induced spreading, lamellipodia formation and migration. C4.4A also associates with galectin‐3 in nontransformed tissues and tumor lines. There is evidence that the association of C4.4A with galectin‐3 influences LN adhesion. C4.4A was described originally as a metastasis‐associated molecule. Our findings that LN1 and LN5 are C4.4A ligands, that galectin‐3 associates with C4.4A and that C4.4A ligand binding confers a migratory phenotype are well in line with the supposed metastasis association. © 2005 Wiley‐Liss, Inc.
Enzymatic detection of precursor cell populations of preneoplastic foci positive for γ‐glutamyltranspeptidase in rat liver
Authors: Satoh Kimihiko , Takahashi Gen , Miura Tomisato , Hayakari Makoto , Hatayama Ichiro
Published: February 2005

An improved staining method for γ‐glutamyltranspeptidase (GGT) was developed using Vibratome‐prepared microslices. Microscopic precursor cell populations of preneoplastic foci positive for the marker enzyme were detectable sequentially in rat liver by tracing back from 5 to 1 week after carcinogen injection in a hepatocarcinogenesis model. Mirror‐image comparisons of serial sections stained for GGT activity and immunocytochemically stained for GST‐P (glutathione S‐transferase P‐form) revealed that GGT expression was confined within GST‐P+ cell populations (GST‐P+ minifoci), which are induced in the periportal area (zone 1) of the liver. GGT expression level differed from one minifocus to another, and the larger the GST‐P+ focus, the stronger was the GGT expression in it, indicating that GST‐P+/GGT− phenotypes are convertible into proliferating GST‐P+/GGT+ ones. Our results suggest that there are at least 2 closely related precursors, GST‐P+/GGT− and GST‐P+/GGT+ phenotypes, of preneoplastic foci in rat chemical hepatocarcinogenesis. © 2005 Wiley‐Liss, Inc.
How does Sarbanes‐Oxley affect outsourcing?
Authors: Cannon David M. , Growe Glenn A.
Published: February 2005

Outsourcing has been a favorite way for many companies to cut costs. But the recently passed Sarbanes‐Oxley Act may mean problems. Management must maintain an effective system of internal control over financial reporting. And this responsibility cannot be transferred to external entities. © 2005 Wiley Periodicals, Inc.
Liquid nitrogen‐based quick freezing: Experiences with bounce‐free delivery of cholinergic nerve terminals to a metal surface
Authors: Phillips Thomas E. , Boyne Alan F.
Published: February 2005

The limitations of chemical fixation in permitting the 1:1 quantitative correlations required for convincing ultrastructural explanations of cell biological processes are noted. We describe techniques for obtaining highly reproducible direct quick freezing on the polished surface of pure copper bars dipping into a static dewar of liquid N2. The importance and the ease of testing and obtaining bounce suppression with commerically available equipment is emphasized. Artefacts caused by tissue damage and bad freezing are illustrated, and a hitherto unrecognized population of presynaptic membrane attached vesicles is described in Torpedine electric organ. Between 15 and 20% of the synaptic vesicles are attached to ca. 30% of the cytoplasmic face of the presynaptic terminal membrane. There is a close correlation between the occurrence of such attachments and the application of electrocyte basal lamina to the external face. We suggest that these vesicles are the ‘membrane operators,’ ‘vesigates,’ and ‘highly active subpopulation’ of vesicles whose existence has been invoked to explain biochemical data in other laboratories. We further speculate that relatively selective Ca pumping by this immediately submembranous population leads to displacement of acetylcholine (ACh) and reloading with newly synthesized ACh. The preferential release of the latter would then be expected.
The preparation of cross‐section specimens for transmission electron microscopy
Authors: Bravman John C. , Sinclair Robert
Published: February 2005

The structure and chemistry of thin solid films are best studied by transmission electron microscopy (TEM) when they are viewed in cross‐section—that is, when the surface normal of the film is made perpendicular to the electron beam. In this orientation, the substrate, the thin film layers, and the interfaces between them can be imaged either simultaneously or individually. Further, information from each of these regions remains distinct from that obtained from the others, eliminating the problems of superimposition that are a consequence of viewing a layered structure in the conventional manner (i.e., parallel to the surface normal). A technique for fabricating TEM specimens that can be viewed in cross‐section is described here. Although the majority of our work is with silicon‐based materials, the technique can be readily adapted to the study of other systems.
Continuous serial thin sectioning for electron microscopy
Authors: Fahrenbach Wolf H.
Published: February 2005

The process of serial sectioning for electron microscopy has been refined such that loss of thin sections is kept below 0.1% and the series is continued at will. The method relies on microscopic control of all manipulative steps, Formvar casting on plate glass for coated slot grids, coating of the block with contact cement for reliable ribboning, pickup by a one‐step method with grid support in the diamond knife trough, staining in LKB grid holders, gentle treatment of grids in the electron microscope, and a slight modification to the microscope for safe grid withdrawal. The results are particularly applicable to the reconstruction of neuronal microcircuits and larger volumes of neuropil.
Ion milling of materials science specimens for electron microscopy: A review
Authors: Howitt D. G.
Published: February 2005

Ion bombardment to perforation is a common technique in the materials sciences by which thin specimens can be prepared for transmission electron microscopy. The process is not without complication and involves radiation damage to the specimen and tends not to preserve the initial specimen topology. Some of the more important facets of the ion‐milling process, pertinent to such specimen preparations, are described.
Some aspects of field emission and field ion microscopy
Authors: Tsong T. T.
Published: February 2005

The field emission microscope can reveal the work function variation of an emitter surface with a spatial resolution of ∼ 25 Å. It is particularly powerful for studying adsorption‐desorption and surface diffusion phenomena. The field ion microscope can resolve single atoms on solid surfaces. Structures of deeper surface layers can be revealed by field evaporation. The chemical identity of surface atoms can be analyzed one by one by time‐of‐flight mass spectrometry in the atom probe. Using these two instruments, behavior of single atoms on metal surface, compositional variations in the surface layers of alloys, and the atomic structures as well as compositional variations of various phases in alloys and materials can be studied with true single atomic layer, spatial resolution. Some aspects of field emission techniques and applications of them to surface science and material characterization are described here.
Maximum‐likelihood estimation applied to electron microscopic autoradiography
Authors: Miller Michael I. , Larson Kenneth B. , Saffitz Jeffrey E. , Snyder Donald L. , Thomas Lewis J.
Published: February 2005

A new method for analysis of electron microscope autoradiographs is described which is based on the maximum‐likelihood method of statistics for estimating the intensities of radioactivity in organelle structures. We adopted a Poisson statistical model to describe the autoradiographic grain distributions that we prove results from the underlying Poisson nature of the radioactive decays as well as the additive errors introduced during the formation of grains. Within the model, an interative procedure derived from the expectation‐maximization algorithm of mathematical statistics is used to generate the maximum‐likelihood estimates. The algorithm has the properties that at every stage of the iteration process the likelihood of the data increases; and for all initial nonzero starting points the algorithm converges to the maximum‐likelihood estimates of the organelle intensities.

The maximum‐likelihood approach differs from the mask‐analysis method, and other published quantitative algorithms in the following ways: (1) In deriving estimates of the radioactivity intensities the maximum‐likelihood algorithm requires that we obtain the actual locations of the grains as well as the micrograph geometries; each micrograph is digitized so that both the grain locations as well as the geometries of the organelle structures can be used. (2) The maximum‐likelihood algorithm iteratively computes the minimum‐meansquared‐error estimate of the underlying emission locations that resulted in the observed grain distributions, from which intensity estimates are generated; this algorithm does not minimize a chi‐squared error statistic. (3) The maximum‐likelihood approach is based on a Poisson model and is therefore valid for low‐count experiments; there are no minimum constraints on data collection for any single organelle compartment. (4) The maximum‐likelihood algorithm requires the form of the point‐spread function describing the emission spread; a probability matrix based on the use of overlay masks is not required. (5) The maximum‐likelihood algorithm does not change for different organelle geometries; arbitrary geometries are incorporated by maximizing the likelihood‐function subject to the geometry constraints.

We have performed a preliminary evaluation of the quantitative accuracy of the maximum‐likelihood and mask‐analysis algorithms. Based on two different phantoms in which we compared the squared error resulting from the two algorithms, we find that the new maximum‐likelihood approach provides substantially improved estimates of the radioactivity intensities of the phantoms.
Transmission electron microscopy of catalysts
Authors: Sanders J. V.
Published: February 2005

The determination of the structures of catalysts is an important step in understanding their behaviour and in developing new or improved catalysts. By their nature, catalysts mostly have a structure which can be resolved only by transmission electron microscopy (TEM) used near its limit of applicability. This article discusses recent selected examples of the use of TEM to examine materials used as catalysts, such as clusters of atoms, small crystalline particles, the materials (oxides) on which these are supported, zeolites, and deposits of carbon which often form on catalysts during catalytic reactions. Interpretation of the images is often aided by the techniques of image processing.
Professor Hashimoto and the theory of two‐beam lattice fringes
Authors: Amelinckx S.
Published: February 2005

A simple theory is presented to explain the origin of two‐beam lattice fringes and to show how they can be used to derive the displacement vector of planar interfaces. The theory may have some value for pedagogical purposes since it provides some insight and emphasizes the similarity with optical interference experiments.
Application of ion beam sputtering for high‐resolution electron microscopy
Authors: Kanaya Koichi , Baba Norio , Muranaka Yoshinori , Adachi Koichi
Published: February 2005

Ion beam sputtering for high‐resolution electron microscopy has basically provided miscellaneous operational features such as atomic shadowing, uncoated observation, and etching of biological specimens coupled with tungsten sputter coating and thinning of solid materials.

Based on the power‐potential law of Lindhard for ionic impact phenomena on metal surfaces, the universal yield‐energy relationship has been derived. Thereby the sputtering deposition rate with reference to the sputtering removal rate was obtained as a function of sputtering yield, and the most important angular distribution of sputtering yield could be measured by using the hemicylindrical specimen stage.

Evidence is presented to show that ion beam sputtering has become one of the most powerful tools for high‐resolution electron microscopy.
Cross‐Section preparation for tem of film‐substrate combinations with a large difference in sputtering yields
Authors: Helmersson Ulf , Sundgren Jan‐Eric
Published: February 2005

The preparation of cross‐section samples of thin films for TEM, may be difficult and tedious, especially if the difference in chemical or physical etching rates is large between the film and the substrate. In this paper, a method is presented whereby cross‐sections can be prepared even if the film and the substrate have a large difference in sputtering yield. By utilizing the strong angular dependence of the sputtering yield and sputter at a low ion incidence angle with respect to the substrate surface of 7–12° and, furthermore, by avoiding sputtering parallel to the interface, samples with homogeneous thickness can be obtained. The technique is demonstrated on reactively sputtered titanium nitride coatings on high speed steel substrates. The difference in sputtering yields is about three for this film‐substrate combination with the substrate being sputtered fastest.
Contamination of thin sections: Some observations on the cause and elimination of “embedding pepper”
Authors: Mollenhauer Hilton H.
Published: February 2005

A method is described for eliminating a form of contamination called embedding pepper that appears in, or on, thin sections following poststaining in lead citrate. The pepper is present most often in the matrixes of mitochondria, peroxisomes, and red blood cells. Formation of pepper can be prevented by treating the section with 0.5 N HCl or 1.0% ethylenediaminete‐traacetic acid (EDTA) for 1–5 min before staining in uranyl acetate or lead citrate.
Observations on the ultrastructural preservation of the nucleus in the myxomycete Physarum polycephalum as observed in resinless sections
Authors: Lachapelle Mario , Lafontaine Jean G.
Published: February 2005

The ultrastructural preservation of the nucleus in both myxamoebae and macroplasmodia of the slime mold Physarum polycephalum was investigated using specimens processed with diethylene glycol distearate or Plexiglass. Following specimen embedding in either of these media, the polymers were dissolved from the semithin sections, which were then dried by the critical point process. In these resinless preparations, nuclei appeared to be pervaded by a complex network of fibrils of various diameters among which granules of different sizes were scattered. At least five different types of fibrils were detected in plasmodial as well as in amoebal nuclei. Resinless preparations obtained from diethylene glycol distearate processed specimens showed a number of easily recognized artifacts, some of which were noticeably less conspicuous when samples were embedded in Plexiglass. In both cases, no indication was obtained that extensive extraction of material had occurred during resin removal by solvents. The various artifacts that were produced following processing with these two media thus seem to have mostly developed during infiltration and hardening, rather than during dissolution of the polymers or critical point drying of the sections.
Principles for the construction and operation of a device for rapidly freezing suspensions for cryo‐electron microscopy
Authors: Murray John M. , Ward Rob
Published: February 2005

Details are given concerning the construction and use of a simple device for preparing samples of frozen‐hydrated biological material embedded in thin films of vitreous ice. The control of humidity around the sample and rate of freezing are of prime importance to obtain good specimens for cryo‐electron microscopy. Symptoms of ill performance of such an apparatus and poor cryo‐manipulation are discussed.
Determination of the crystallographic directions and planes of features and of the misorientations of crystals with high accuracy and internal estimation of errors
Authors: Chen Fu‐Rong , King A. H.
Published: February 2005

Techniques are given for maximizing the accuracy of crystallographic measurements in the transmission electron microscope. In particular, line directions, plane orientations, and crystal misorientations are treated, and for each case the methods of data collection, refinement, and error estimation are given. These methods represent generalizations of Ball's optimizing crystallographic technique (Ball: Philos. Mag. A44:1307–1317, 1981), and we also provide extensions to hexagonal lattice applications.
Microvascular casting of the lung: Effects of various fixation protocols
Authors: Schraufnagel Dean E. , Schmid Aloisia
Published: February 2005

Although techniques for preparing specimens for light and electron microscopy are well established, few studies have sought to establish methods for corrosion casting of the microscopic vessels of the lung. The effects of two concentrations of glutaraldehyde, formaldehyde, and no fixative (saline control) on the filling and structure of the microvascular casts of the lung were studied. All fixatives were infused 5 minutes before casting.

Formaldehyde's fixation effects were intermediate between those of glutaraldehyde and no fixation. Leakage of casting material was increased in the animals that were fixed less. Digestion time was prolonged and more undigested tissue was found in the group receiving the concentrated glutaraldehyde, although the difference in neither of these features alone reached statistical significance. Circumferential bands occurred more frequently in the large vessel casts of the less fixed animals, which may account for the less filling microvasculature in these lungs. However, good quality casts were obtained with each method.