julilili42/papers huggingface dataset:
Serum response factor is crucial for actin cytoskeletal organization and focal adhesion assembly in embryonic stem cells
2002-02-11

The activity of serum response factor (SRF), an essential transcription factor in mouse gastrulation, is regulated by changes in actin dynamics. Using Srf(−/−) embryonic stem (ES) cells, we demonstrate that SRF deficiency causes impairments in ES cell spreading, adhesion, and migration. These defects correlate with defective formation of cytoskeletal structures, namely actin stress fibers and focal adhesion (FA) plaques. The FA proteins FA kinase (FAK), β1-integrin, talin, zyxin, and vinculin were downregulated and/or mislocalized in ES cells lacking SRF, leading to inefficient activation of the FA signaling kinase FAK. Reduced overall actin expression levels in Srf(−/−) ES cells were accompanied by an offset treadmilling equilibrium, resulting in lowered F-actin levels. Expression of active RhoA-V14 rescued F-actin synthesis but not stress fiber formation. Introduction of constitutively active SRF-VP16 into Srf(−/−) ES cells, on the other hand, strongly induced expression of FA components and F-actin synthesis, leading to a dramatic reorganization of actin filaments into stress fibers and lamellipodia. Thus, using ES cell genetics, we demonstrate for the first time the importance of SRF for the formation of actin-directed cytoskeletal structures that determine cell spreading, adhesion, and migration. Our findings suggest an involvement of SRF in cell migratory processes in multicellular organisms.
Mutation A1555G in the 12S rRNA gene and its epidemiological importance in German, Hungarian, and Polish patients
2002-02-13

The A1555G mutation in the 12SrRNA gene has been associated with aminoglycoside induced and nonsyndromic sensorineural hearing impairment. In this study we analyzed Hungarian, Polish and German patients with nonsyndromic severe to profound hearing impairment of unknown origin for this mutation. The frequency of the A1555G mutation in the Hungarian hearing impaired population was below 1.8 %. Three out of 125 Polish patients carrying the A1555G mutation were identified. Among German patients one carrier was found (0.7 %) revealing a homoplastic A1555G mutation, whereas no mutation was detected in control individuals with normal hearing (frequency < 0.6%). In summary the frequencies of the A1555G mutation are low in the hearing impaired as well as in the normal population in Hungary, Poland and Germany. Since the importance of this mutation and its relationship with aminoglycoside exposure is not well understood yet, patients with nonsyndromic hearing impairment should be routinely screened for this mutation to avoid aminoglycoside induced hearing impairment due to increased sensitivity of maternal relatives.
Proteasome-Assisted Identification of a SSX-2-Derived Epitope Recognized by Tumor-Reactive CTL Infiltrating Metastatic Melanoma
2002-02-15

Abstract The tumor Ag SSX-2 (HOM-MEL-40) was found by serological identification of Ags by recombinant expression cloning and was shown to be a cancer/testis Ag expressed in a wide variety of tumors. It may therefore represent a source of CD8+ T cell epitopes useful for specific immunotherapy of cancer. To identify potential SSX-2-derived epitopes that can be recognized by CD8+ T cells, we used an approach that combined: 1) the in vitro proteasomal digestion of precursor peptides overlapping the complete SSX-2 sequence; 2) the prediction of SSX-2-derived peptides with an appropriate HLA-A2 binding score; and 3) the analysis of a tumor-infiltrated lymph node cell population from an HLA-A2+ melanoma patient with detectable anti-SSX-2 serum Abs. This strategy allowed us to identify peptide SSX-241–49 as an HLA-A2-restricted epitope. SSX241–49-specific CD8+ T cells were readily detectable in the tumor-infiltrated lymph node population by multimer staining, and CTL clones isolated by multimer-guided cell sorting were able to lyse HLA-A2+ tumor cells expressing SSX-2.
The double torus as a 2D cosmos: groups, geometry and closed geodesics
2002-02-18

The double torus provides a relativistic model for a closed 2D cosmos with topology of genus 2 and constant negative curvature. Its unfolding into an octagon extends to an octagonal tessellation of its universal covering, the hyperbolic space H^2. The tessellation is analysed with tools from hyperbolic crystallography. Actions on H^2 of groups/subgroups are identified for SU(1, 1), for a hyperbolic Coxeter group acting also on SU(1, 1), and for the homotopy group \\Phi_2 whose extension is normal in the Coxeter group. Closed geodesics arise from links on H^2 between octagon centres. The direction and length of the shortest closed geodesics is computed.
ChemInform Abstract: Interpenetrating Cluster Chains in the Structure of K0.77Nb6Cl15.
2002-02-19

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Separation of Structural Isomers of 2(3),9(10),16(17),23(24)‐Tetrasubstituted Phthalocyanines.
2002-02-19

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Detecting Planets in Protoplanetary Disks: A Prospective Study
2002-02-20

We investigate the possibility to find evidence for planets in circumstellar disks by infrared and submillimeter interferometry. We present simulations of a circumstellar disk around a solar-type star with an embedded planet of 1 Jupiter mass. The three-dimensional (3D) density structure of the disk results from hydrodynamical simulations. On the basis of 3D radiative transfer simulations, images of this system were calculated. The intensity maps provide the basis for the simulation of the interferometers VLTI (equipped with the mid-infrared instrument MIDI) and ALMA. While MIDI/VLTI will not provide the possibility to distinguish between disks with or without a gap on the basis of visibility measurements, ALMA will provide the necessary basis for a direct gap detection.
Localization of metals in cells of saprophagous soil arthropods (Isopoda, Diplopoda, Collembola)
2002-02-21

Abstract This review summarizes results on the intracellular distribution of metals in cells of woodlice (Isopoda), millipedes (Diplopoda), and springtails (Collembola), which are three major groups of saprophagous arthropods contributing to the turnover of soil organic matter. Although the impact of metals and also metal pollution has inevitably been shown at levels of higher biological organization than subcellular mechanisms in these animal groups, the aim of this review is to focus exclusively on storage sites and aspects of intracellular metal metabolism. Thus, methodologically, results obtained by microscopical techniques such as histochemistry, X‐ray microanalysis, energy filter transmission electron microscopy, or laser microprobe mass spectrometry were given preference. Results from atomic absorption spectrophotometry of cellular fractions were kept to a minimum. In all three taxa, the main intracellular metal storage sites are various types of “granules” which are widely distributed throughout cell types associated with the digestive system. Microsc. Res. Tech. 56:393–401, 2002. © 2002 Wiley‐Liss, Inc.
Quantitative phase analysis of PBSCCO 2223 precursor powders—an XRD/Rietveld refinement study
2002-02-22

We analysed x-ray powder diffraction data of spray pyrolytic precursor powders for the oxide-powder-in-tube (OPIT) technology by means of the Rietveld method. For calcinations in air we find a typical phase composition of 2212, 14-24, 11, CP and 3321 at 800 °C (13 h). At 820 °C 2212 is in equilibrium with 14-24 and CP after 48 h calcination. In 8% O2 at 800 °C 2212 exists together with 14-24, 21, CP and CuO, in 99.999% N2 at 760 °C the stable phase assemblage consists of 2212, 21 and CuO. The highest amount of 2212 can be found in the powder calcined at 8% O2 (72.4 wt%) compared with 68.9 wt% for the powder calcined in 21% O2 and 69.3 wt% for the powder calcined in flowing N2. A first trace of 2223 can be observed in powders calcined in air at temperatures of 838 °C and 842 °C. The crystallographic features of the 2212 phase correlate with the calcination atmosphere: under reducing atmospheres the satellite reflections of the x-ray powder diffractogram disappear and the orthorhombic lattice distortion z increases due to Pb2+-incorporation into 2212. With increasing O-content the c lattice parameter becomes significantly shorter in samples calcined in oxidizing atmospheres. It is possible to infer a cationic ratio of Sr:(Sr + Ca) ≈ 0.12 for the 11 phase and Ca:(Ca + Sr + Bi) ≈ 0.57 for 14-24 in precursors from lattice parameter data.
Thyroid hormone is a critical determinant for the regulation of the cochlear motor protein prestin
2002-02-26

The most impressive property of outer hair cells (OHCs) is their ability to change their length at high acoustic frequencies, thus providing the exquisite sensitivity and frequency-resolving capacity of the mammalian hearing organ. Prestin, a protein related to a sulfate/anion transport protein, recently has been identified and proposed as the OHC motor molecule. Homology searches of 1.5 kb of genomic DNA 5′ of the coding region of the prestin gene allowed the identification of a thyroid hormone (TH) response element (TRE) in the first intron upstream of the prestin ATG codon. Prestin TRE bound TH receptors as a monomer or presumptive heterodimer and mediated a triiodothyronine-dependent transactivation of a heterologous promotor in response to triiodothyronine receptors α and β. Retinoid X receptor-α had an additive effect. Expression of prestin mRNA and prestin protein was reduced strongly in the absence of TH. Although prestin protein typically was redistributed to the lateral membrane before the onset of hearing, an immature pattern of prestin protein distribution across the entire OHC membrane was noted in hypothyroid rats. The data suggest TH as a first transcriptional regulator of the motor protein prestin and as a direct or indirect modulator of subcellular prestin distribution.
ChemInform Abstract: Syntheses of Hapalosin Analogues by Solid‐Phase Assembly of Acyclic Precursors.
2002-02-26

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Density-functional calculations in a two-dimensional finite-element basis for atoms in very strong magnetic fields: Energy values
2002-02-27

Results of density-functional calculations for atoms in very strong magnetic fields using a two-dimensional finite-element basis set are reported for ground-state energies of helium, carbon, and neon, and for some excited states of helium. We give results obtained by using three different local-density functionals. A comparison with multi-Landau-channel Hartree-Fock calculations shows reasonable agreement for helium.
Multiple Equilibria
2002-02-27

Diffusion Interaction of Ligands and Macromolecules Binding Constants Derivation of the Binding Equation Macromolecules with Identical Independent Binding Sites General Binding Equation Graphic Representation of the General Binding Equation Binding of Various Ligands, Competition Macromolecules with Non-Identical, Independent Binding Sites Macromolecules with Identical, Interacting Binding Sites, Cooperativity The Hill Equation The Adair Equation The Pauling Model Allosteric Enzymes The Symmetry Model The Sequential Model and Negative Cooperativity Physiological Aspects of Cooperativity Analysis of Cooperativity Examples of Allosteric Enzymes Non-Identical, Interacting Binding Sites References
Successful Combined Modality Therapy of Primary Suprasellar Malignant Melanoma
2002-02-27

Bei einem 42-jährigen Patienten mit rechts temporaler Anopsie, verschwommenem Sehen und Geruchseinschränkung wurde der Verdacht auf einen suprasellar gelegenen Tumor mit Beteiligung des Sehnervs und des Chiasma opticus geäußert. Die histopathologische Aufarbeitung konnte ein primär suprasellär gelegenes malignes Melanom sichern. Die enge Lagebeziehung und Infiltration der Sehbahn erlaubte keine radikale Resektion, so dass eine postoperative lokale Strahlentherapie der suprasellären Region mit einer Gesamtdosis von 55.8 Gy, Einzeldosis 1.8 Gy, indiziert wurde. 78 Monate nach Therapie konnte eine anhaltende lokale Tumorkontrolle mittels MRT und klinischer Untersuchung ohne Hinweis für signifikante Spätreaktionen am zentralen Nervensystem nachgewiesen werden. Die kombinierte Behandlung aus eingeschränkter Operation und nachfolgender Strahlentherapie kann bei dieser seltenen suprasellär gelegenen Tumorentität in kurativer Intention eingesetzt werden.
Methods
2002-02-27

Methods for the Investigation of Multiple Equilibria Equilibrium Dialysis and General Aspects of Binding Measurements Continuous Equilibrium Dialysis Ultrafiltration Gel Filtration Ultracentrifugation Methods Electrochemical Methods The Oxygen Electrode The CO2 Electrode Potentiometry, Oxidation-Reduction Potentials The pH-Stat Polarography Calorimetry Spectroscopic Methods Absorption Spectroscopy Bioluminescence Fluorescence Circular Dichroism and Optical Rotation Dispersion Infrared and Raman Spectroscopy Electron Spin Resonance Spectroscopy Measurement of Fast Reactions Flow Methods Relaxation Methods Flash Photolysis, Pico- and Femtoseconds Spectroscopy Evaluation of Rapid Kinetic Reactions (Transient Kinetics) References
Destruction of neurons by cytotoxic T cells: A new pathogenic mechanism in rasmussen's encephalitis
2002-02-28

Abstract Rasmussen's encephalitis is a progressive epileptic disorder characterized by unihemispheric lymphocytic infiltrates, microglial nodules, and neuronal loss leading to the destruction of the affected hemisphere. In this study, immunohistochemical evaluation of specimens from 11 patients revealed lymphocytic infiltrates that consisted mainly of CD3 + CD8 + T cells. Of these cells, 7.0% lay in direct apposition to MHC class I + neurons. Confocal laser microscopy revealed that these lymphocytes contained granzyme B in a polar orientation toward these perikarya. Single neurons underwent apoptosis. These findings indicate that a T‐cell–mediated cytotoxic reaction induces neuronal death in Rasmussen's encephalitis. This study directly shows, for what we believe is the first time, that a cytotoxic T‐cell mechanism contributes to loss of neurons in human brain disease.
Protein surveillance machinery in brains with spinocerebellar ataxia type 3: Redistribution and differential recruitment of 26S proteasome subunits and chaperones to neuronal intranuclear inclusions
2002-02-28

Abstract Intracellular aggregates commonly forming neuronal intranuclear inclusions are neuropathological hallmarks of spinocerebellar ataxia type 3 and of other disorders characterized by expanded polyglutamine‐(poly‐Q) tracts. To characterize cellular responses to these aggregates, we performed an immunohistochemical analysis of neuronal intranuclear inclusions in pontine neurons of patients affected by spinocerebellar ataxia type 3, using a panel of antibodies directed against chaperones and proteasome subunits. A subset of the neuronal intranuclear inclusions stained positively for the chaperones Hsp90α and HDJ‐2, a member of the Hsp40 family. Most neuronal intranuclear inclusions were ubiquitin positive, suggesting degradation by ubiquitin‐dependent proteasome pathways. Surprisingly, only a fraction of neuronal intranuclear inclusions were immunopositive for antibodies directed against subunits of the 20S proteolytic core, whereas most inclusions were stained by antibodies directed against subunits of the 11S and 19S regulatory particles. These results suggest that the proteosomal proteolytic machinery that actively degrades neuronal intranuclear inclusions is assembled in only a fraction of pontine neurons in end stage spinocerebellar ataxia type 3. The dissociation between regulatory subunits and the proteolytic core and the changes in subcellular subunit distribution suggest perturbations of the proteosomal machinery in spinocerebellar ataxia type 3 brains.
Intracranial oscillations of cerebrospinal fluid and blood flows: Analysis with magnetic resonance imaging
2002-02-28

Abstract Purpose To detect oscillations of the cerebrospinal fluid (CSF) flow related to the heartbeat and frequencies lower than 0.6 Hz and to compare these oscillations of CSF and blood flow in cerebral vessels by using echo planar imaging in real time mode. The existence of such waves has been well known but has not yet been shown by MRI. Materials and Methods In a slice perpendicular to the aqueduct, CSF flow as well as CBF, could be determined in sagittal sinus, basilar artery, and capillary vessels. After Fourier analysis, four frequency bands were assigned. Results In the very high‐frequency (heart rate) range, the integrals under the CSF curves were more closely related to arterial CBF than to changes in the sinus. Also, in the high‐frequency (respiration rate), low‐frequency (0.05–0.15 Hz), and very‐low‐frequency (0.008–0.05 Hz) ranges, the integrals under the CSF curves corresponded with arterial and capillary CBF. Conclusion Slow and fast oscillations in CSF flow are detectable in healthy persons with a proportional allotment to arterial and capillary CBF. J. Magn. Reson. Imaging 2002;15:251–258. © 2002 Wiley‐Liss, Inc.
marvin: A Platform for Chemoinformatics Software Development
2002-02-28

A strategy for a new type of platform for chemoinformatics software development and its first implementation are presented. The basic task of such a platform is to apply sequences of computational methods to high numbers of molecules. The implementation presented is based on four major components: (a) the application manager, responsible for running programs and for data management; (b) executable applications that supply limited pieces of functionality; (c) syntax definitions for data and control files and (d) the runtime library which comprises routines for data handling and user interface. This simple concept is implemented in the software package marvin. Different computational methods are available within marvin, including parts of commercial software packages (e.g. molecular modeling, bioinformatics, statistics, etc.) as well as newly developed and innovative algorithms. The basic layout of marvin is described and a simple example illustrates its application.
1,3-Bis(2,4-dibromophenyl)triazene
2002-02-28

The crystal structure of the title compound, C(12)H(7)Br(4)N(3), shows that the stereochemistry about the N[double bond]N double bond of the N[double bond]N-N(H) moiety is trans. The whole molecule deviates slightly from planarity (r.m.s. deviation 0.164 A). While one of the aryl substituents is almost coplanar with the triazene chain, weak intermolecular Br...C contacts cause the second aryl substituent to deviate by an angle of 9.1 (8) from the plane defined by the N[double bond]N-N group. Weak intermolecular N-H...Br interactions between molecules related by the diagonal glide plane give rise to chains, which are stacked along the [100] crystallographic direction. An unequal distribution of double-bond character between the N atoms suggests a delocalization of pi electrons over the diazoamino group and the adjacent aryl groups.
The prevalence of radiologic TMJ findings and self-reported orofacial pain in a patient group wearing implant dentures.
2002-02-28

Radiologic signs of TMJ-OA were common findings. The study gave no indication that long-term wearing of an implant prosthesis has a negative effect on TMJ-OA. It was not possible to predict orofacial pain from radiologic TMJ-OA signs.
Staphylococcus and biofilms
2002-03-01

Summary The genetic and molecular basis of biofilm formation in staphylococci is multifaceted. The ability to form a biofilm affords at least two properties: the adherence of cells to a surface and accumulation to form multilayered cell clusters. A trademark is the production of the slime substance PIA, a polysaccharide composed of β ‐1,6‐linked N ‐acetylglucosamines with partly deacetylated residues, in which the cells are embedded and protected against the host’s immune defence and antibiotic treatment. Mutations in the corresponding biosynthesis genes ( ica operon) lead to a pleiotropic phenotype; the cells are biofilm and haemagglutination negative, less virulent and less adhesive on hydrophilic surfaces. ica expression is modulated by various environmental conditions, appears to be controlled by SigB and can be turned on and off by insertion sequence (IS) elements. A number of biofilm‐negative mutants have been isolated in which polysaccharide intercellular adhesin (PIA) production appears to be unaffected. Two of the characterized mutants are affected in the major autolysin ( atlE ) and in D ‐alanine esterification of teichoic acids ( dltA ). Proteins have been identified that are also involved in biofilm formation, such as the accumulation‐associated protein (AAP), the clumping factor A (ClfA), the staphylococcal surface protein (SSP1) and the biofilm‐associated protein (Bap). Concepts for the prevention of obstinate polymer‐associated infections include the search for new anti‐infectives active in biofilms and new biocompatible materials that complicate biofilm formation and the development of vaccines.
Astrophysical Reaction Rate of12C(α, γ)16O
2002-03-01

A new astrophysical reaction rate of 12C(α, γ)16O has been calculated based on our recent determination of the E1- and E2-capture cross sections. The R-matrix method has been applied to describe the SE1- and SE2-factor functions as well as the data of elastic α scattering and the β-delayed α decay of 16N from other experiments. The resulting reaction rate for stellar temperatures of T9 = 0.04-10 is presented in both tabular form and an analytic expression. A new temperature dependence of the reaction rate was obtained when compared with reported evaluations. The associated uncertainties were reduced considerably in comparison to previous determinations.
Imported Falciparum Malaria in Europe: Sentinel Surveillance Data from the European Network on Surveillance of Imported Infectious Diseases
2002-03-01

Malaria continues to have a high morbidity rate associated among European travelers. Thorough recording of epidemiological and clinical aspects of imported malaria has been helpful in the detection of new outbreaks and areas of developing drug resistance. Sentinel surveillance of data collected prospectively since 1999 has begun within TropNetEurop, a European network focusing on imported infectious diseases. TropNetEurop appears to cover approximately 10% of all patients with malaria seen in Europe. Reports of 1659 immigrants and European patients with Plasmodium falciparum malaria were analyzed for epidemiological information and data on clinical features. Regional data were quite diverse, reflecting local patterns of immigration and international travel. By far, the most infections were imported from West Africa. Europeans had more clinical complications; consequently, all deaths occurred in this group. Compared with European standards, the mortality rate was low (0.6% in Europeans). Data from TropNetEurop member sites can contribute to our understanding of the epidemiological and clinical findings regarding imported falciparum malaria.